Predictors and outcomes of peritoneal dialysis-related infections due to filamentous molds (MycoPDICS).

INTRODUCTION: We sought to evaluate the predictors and outcomes of mold peritonitis in patients with peritoneal dialysis (PD).
METHODS: This cohort study included PD patients from the MycoPDICS database who had fungal peritonitis between July 2015-June 2020. Patient outcomes were analyzed by Kaplan Meier curves and the Log-rank test. Multivariable Cox proportional hazards model regression was used to estimating associations between fungal types and patients' outcomes.
RESULTS: The study included 304 fungal peritonitis episodes (yeasts n = 129, hyaline molds n = 122, non-hyaline molds n = 44, and mixed fungi n = 9) in 303 patients. Fungal infections were common during the wet season (p <0.001). Mold peritonitis was significantly more frequent in patients with higher hemoglobin levels, presentations with catheter problems, and positive galactomannan (a fungal cell wall component) tests. Patient survival rates were lowest for non-hyaline mold peritonitis. A higher hazard of death was significantly associated with leaving the catheter in-situ (adjusted hazard ratio [HR] = 6.15, 95%confidence interval [CI]: 2.86-13.23) or delaying catheter removal after the diagnosis of fungal peritonitis (HR = 1.56, 95%CI: 1.00-2.44), as well as not receiving antifungal treatment (HR = 2.23, 95%CI: 1.25-4.01) or receiving it for less than 2 weeks (HR = 2.13, 95%CI: 1.33-3.43). Each additional day of antifungal therapy beyond the minimum 14-day duration was associated with a 2% lower risk of death (HR = 0.98, 95%CI: 0.95-0.999).
CONCLUSION: Non-hyaline-mold peritonitis had worse survival. Longer duration and higher daily dosage of antifungal treatment were associated with better survival. Deviations from the 2016 ISPD Peritonitis Guideline recommendations concerning treatment duration and catheter removal timing were independently associated with higher mortality.

Introduction

Fungal peritonitis is substantially more common in patients with peritoneal dialysis (PD) compared to the general population [1] and has high mortality ranging between 4.0 and 60.5% [2-16]. Retrospective studies and registries have demonstrated that fungal peritonitis accounts for between 1% and 24% of all peritonitis episodes in people undergoing PD, with absolute rates ranging from 0.01–0.09 episode/patient-year [2-17]. The highest prevalence has been reported in tropical countries, such as India, where the rates are as high as 24% (0.09 episodes/year) [7,9]. Although approximately 80 fungal species have been demonstrated as potentially causative organisms, Candida spp. is the predominant pathogen causing fungal peritonitis [2-11,13-16], whilst filamentous mold-associated peritonitis variably accounts for between 0% and 32% of fungal peritonitis episodes [2-4,7,9,11,14,16]. Clinically, both types of fungal peritonitis seem to manifest similarly in the literature. Therefore, the 2016 International Society for Peritoneal Dialysis (ISPD) Peritonitis Guidelines strongly recommend removing the PD catheter immediately after fungi are identified in PD patients with fungal peritonitis (1C), followed by a continuation of antifungal agents for an additional 2 more weeks (2C). No specific recommendations are made regarding the type and dose of antifungal medications to be administered [18]. However, these clinical speculation and recommendations are based mainly on studies of Candida peritonitis.

To date, only 3 retrospective studies have compared peritonitis outcomes between different causative fungal species. Wong et al. [4] demonstrated similar mortality rates between Candida and non-Candida species (47% vs. 37%). In contrast, Lo et al. [6] showed that C. parapsilosis was associated with higher mortality than other Candida species. Chang et al. [11] found that C. albicans infection was a predictor of mortality compared to non-Candida fungi in univariate analysis but not in multivariable analysis. However, the results of previous studies should be interpreted with caution because of the comparatively small number of filamentous mold peritonitis episodes (less than 20 episodes) in each group. We leveraged the comprehensive Thailand Fungal PD-related Infectious Complications Surveillance (MycoPDICS) database to overcome these limitations. This surveillance registry was specifically designed to capture fastidious organisms causing PD-related infection, to conduct adequately powered, multivariable-adjusted comparisons of types of pathogens in PD patients with fungal peritonitis to better elucidate predictors and outcomes of mold peritonitis in patients with PD.

Materials and methods

Study design and population

This study included adult PD patients (≥18 years) recorded in the MycoPDICS database who had fungal peritonitis and catheter-related fungal infection between July 2015-June 2020. Written informed consent was obtained from all the participants or their legal substitute decision-makers. The study was approved by the Chulalongkorn University Institutional Review Board. To be eligible for inclusion, participants had to fulfill the 2016 ISPD Peritonitis Guidelines diagnostic criteria for peritonitis [18] by the presence of at least 2 of the following: 1) clinical symptoms of peritoneal inflammation, including abdominal pain and cloudy dialysate; 2) more than 100 leukocytes/mm3 in PD effluent (PDE) with at least 50% neutrophils; 3) documentation of fungi in PDE or PD catheter by either smear or culture. The study was also registered in the Thai Clinical Trials Registry (Registration Number TCTR20210521009).

Data collection

The MycoPDICS database is a national registry designed to survey the incidence of PD-related infections with fungus or environmental organisms under the Nephrology Society of Thailand (NST). It has been launched since the perceived burden of fungal peritonitis was high. The objectives of this surveillance include 1) monitoring fungal and environmental infections in PD patients, disease trends, and risk factors; 2) estimating the burden of disease; 3) providing pathogen isolates, detecting new pathogens, and monitoring for emerging antifungal resistance; and 4) supporting treatment platforms. The single case investigation involves 1) communication with the index patient and/or their caregivers using a semi-structured questionnaire on possible risk factors for infection and describing the household environment; 2) transportion of the suspected PD specimens to the central laboratory within 24 hours in an ice-shield container for organism identification, including PD bag, serum, and PD catheter (as needed). Identified species and antifungal agent susceptibility summaries are distributed back to the reporting units as soon as the results are available. The treatment regimen and schedule is under the attending physician’s clinical judgment. 3) Collecting patient-level and facility-level information using a standard protocol and data collection instruments in all voluntary participating facilities. NST also undertakes a verification procedure through communication with the primary physicians and reference PD nurses to confirm the index case.

The retrieved data for this study included patient demographics, comorbidities at the start of dialysis, presenting symptoms and signs, presence of coexisting bacterial peritonitis, antibiotic use within the 3 months before fungal peritonitis, laboratory data at the onset of peritonitis, species of pathologic fungus and fungal characteristics, the initial and subsequent antimicrobial treatment, catheter removal and the time of removal, and patient outcomes.

Definition

PD catheter malfunction was defined as mechanical failure to attain and maintain dialysate inflow or outflow sufficient to perform PD. Death related to fungal peritonitis was defined as the death of a patient with active peritonitis or sepsis secondary to peritonitis or within 4 weeks of initial diagnosis of fungal peritonitis [18]. According to wet smear, fungi were categorized into 3 groups: yeast, hyaline mold, and non-hyaline mold. For polymicrobial infections, fungal peritonitis was included if a fungus was at least one of the isolated organisms. Mixed fungal infection was defined as a concomitant infection with more than one species of fungus.

Organism identification

At the central laboratory, 3 bottles of 50 mL of PDE obtained from the submitted PD bags were centrifuged at 3,500g for 15 minutes, and the supernatants were subsequently discarded. The remaining solution (around 5 mL) was mixed up with pellet and injected into bacterial and mycobacterial broths/agars to exclude concomitant bacterial/mycobacterial infection, including Bactec Plus Aerobic/F, BACTEC Plus Anaerobic/F vials (Dun Laoghaire, Ireland), BACTEC MGIT 960 media, Ogawa medium slants, blood agar, MacConkey agar (Oxoid, Basing-stoke, UK), Chocolate agar (Oxoid, Basing-stoke, UK), and specific agar plates (as needed) for 5–7 days (bacteria) and 2 months (mycobacteria) at 37°C. For fungal culture, the pellet from another 50 mL of centrifuged PDE was streaked on Sabouraud dextrose agar (SDA) and specific agar plates (as needed), then incubated at 25°C and 37°C for 15–30 days. Yeast-form fungi were identified by API20c AUX kit (bioM´erieux, Marcy l’Etoile, France) based on biochemical reactions. Mold-form fungi were classified based on their sexual spores and conidia morphology.

Species were confirmed by molecular phylogeny using nucleotide sequences of internal transcribed spacer (ITS1/ITS4 primer; White et al., 1990) and large subunit region (5.8SR/LR7 primer; Vilgalys lab, Duke University) of the ribosomal RNA gene. The reaction mixture with fungal DNA was utilized as a positive control, and the reaction mixture without a template was used as a negative control. The experiments were repeated twice. The purified PCR products were then outsourced for Sanger sequencing service (First BASE Laboratories, Singapore Science Park II, Singapore). The sequencing results were subjected to BLASTN (National Center for Biotechnology Information Internet homepage) search against the GenBank database for homology identities. Antifungal susceptibility patterns of yeast and mold against common antifungal medications were assessed by Epsilometer test (bioMérieux, Marcy l’ Etoile, France) and broth dilution technique (according to the CLSI document M38-A2 protocol), respectively.

Statistical analysis

Results were expressed as frequencies and percentages for categorical variables and median and IQR for continuous variables. Differences between the three groups of patients were analyzed by the χ2-test and Fisher’s exact test for categorical data and the Kruskal-Wallis test for continuous data. Only variables with missing less than 20% were included for analysis. After excluding mixed fungal infection, all primary patient outcomes were analyzed by survival analyses using Kaplan Meier curves together with the Log-rank test. Associations between variables and patient outcomes were first analyzed by univariate Cox proportional hazard regression. All variables with p values of 0.20 or less were candidates for the multivariable Cox model with adjustment for age, gender, diabetes, employment status, PD vintage, hemoglobin, serum albumin, and high PDE leukocyte count. The assumption of proportional hazards was verified using Schoenfeld residuals and plots. Data were analyzed using the software packages Stata 16.1 (College Station, TX) and R 4.0.5 (R Core Team, Vienna). P-values less than 0.05 were considered statistically significant.

Results and discussion

Study population and distribution of fungal categories

Of 349 PD patients with fungal peritonitis (352 episodes) from 48 facilities in the MycoPDICS database, 305 episodes (304 participants) were fulfilled the criteria of diagnosis of fungal peritonitis. After excluding a case with an unknown patient outcome, 304 episodes in 303 participants were included in the current study (Fig 1). According to fungal morphology in wet smear, isolates included yeast (n = 129, 42%), hyaline mold (n = 122, 40%), non-hyaline mold (n = 44, 15%), and mixed fungi (n = 9, 3%). The most common yeast was C. parapsilosis (35%), followed by C. tropicalis (12%), and C. albicans (11%). Non-candida yeasts were found in 19% (n = 24). The three most common hyaline molds were Aspergillus (n = 52), Fusarium (n = 29), and Penicillium (n = 15). Dematiaceous mold (is termed if the fungal morphology or colonies appear as black or off-black colors) was the predominant non-hyaline mold (91%), including Curvularia (n = 15), Cladosporium (n = 8), Exophiala (n = 5), and Bipolaris (n = 3). A list of all fungal species isolated and categorized based on a wet smear is depicted in Table 1.

Fig 1

Patient flow diagram.

Table 1

Spectrum of fungal organisms isolated from fungal peritonitis episodes.

Yeast (n = 129)		Hyaline mold (n = 122)		Non-hyaline mold (n = 44)
• Candida (C. parapsilosis, 45; C. tropicalis, 15; C. albicans, 14; C. guillermondii, 10; C. krusei, 2; others, 11)	105	• Aspergillus (A. flavus, 30; A. niger, 6; A. terreus, 3; A. fumigatus, 3;A. versicolor, 2; Others 8)	52	• Curvularia (C. lunata, 8; Curvularia spp., 4; C. hawaiiensis, 2; C. geniculate, 1)	15
• Trichosporon* (T. asahii, 6; other, 1)	7	• Fusarium (F. solani, 15; others 14)	29	• Cladosporium (Cladosporium spp., 6; C. sphaerospermum, 1; C. tenuissimum, 1)	8
• Kodamaea (K. ohmeri, 6)	6	• Penicillium (P. citrinum, 6; P. rubens, 1; Others 8)	15	• Exophiala (Exophiala spp., 2; E. spinifera, 2; E. dermatitidis, 1)	5
• Blastobotrys (B. adeninivorans, 3; B. raffinosifermentans, 2)	5	• Paecilomyces (Paecilomyces spp., 3; P. formosus, 2; P. variotii, 1)	6	• Bipolaris (Bipolaris spp., 3)	3
• Cryptococcus* (C. laurentii, 1; other, 1)	2	• Acremonium (A. implicatum, 1; A. obclavatum, 1, Others, 3)	5	• Exserohilum (Exserohilum spp., 1; E. rostratum, 1)	2
• Hyphopichia (H. burtonii, 1)	1	• Scedosporium (Scedosporium spp., 2; S. apiospermum, 1)	3	• Alternaria (A. alternate, 1)	1
• Rhodotorula* (R. minuta, 1)	1	• Trichothecium (Trichothecium spp., 2)	2	• Cunninghamella** (C. bertholletiae, 1; C. echinulata, 1)	2
• Others (2)	1	• Others (C. intermedia, 1)	10	• Others	7

Patient and clinical characteristics by fungal category

The mean age was 58 [49-66] years. The average PDE leukocyte count was 1,200 [400-3,100] cells/μL with neutrophil predominance (83 [70-91]%). Exposure to antibiotics within 3 months prior to peritonitis was found in 42% of episodes. Of note, 8% of episodes (n = 24) had concomitant bacterial infection (Acinetobacter baumannii, 4; Enterococcus faecium, 3; others, 17). The median time from peritonitis onset to diagnosis of fungal peritonitis was 10 [6-17] days. Hypokalemia (defined as serum potassium <3.5 mEq/L) was found in 48% (n = 132) while hypoalbuminemia (defined as serum albumin <3.5 g/dL) was found in 83% (n = 226). Fungal infections—both yeasts and molds—were significantly more common during the wet season (Fig 2). Compared with yeast peritonitis, mold peritonitis was significantly more frequent in patients with higher hemoglobin levels, presentations with catheter malfunction or intraluminal colonization, and positive galactomannan (a fungal cell wall component that is shed by fungi during their growth and death) tests. Hyaline mold peritonitis had the lowest PD effluent (PDE) neutrophil percentage (Table 2).

Fig 2

Seasonal variation in the prevalence of fungal peritonitis episode according to fungal type by wet smear.

Table 2

Demographic, clinical and laboratory characteristics, and treatment of PD patients with fungal peritonitis according to fungal type.

Variables	Total (304)	Yeast (129)	Hyaline Mold (122)	Non-Hyaline Mold (44)	P value**
Demographics
Age, years	58 [49–66]	58 [49–67]	56 [47–65]	60 [53–64]	0.40a
Male gender, %	154 (50.7)	65 (50.4)	61 (50.0)	24 (54.6)	0.87b
Diabetes, %	130 (44.4)	47 (37.6)	54 (46.2)	22 (52.4)	0.18b
Employed, %	169 (60.4)	74 (63.3)	67 (60.4)	23 (53.5)	0.53b
Automated PD, %	5 (1.7)	3 (2.4)	2 (1.7)	0 (0.0)	0.85c
PD vintage, years	2.0 [1.0–3.6]	2.1 [1.0–3.9]	1.9 [0.8–3.7]	2.1 [1.1–4.4]	0.66a
Clinical characteristics
Peritonitis only, %	112 (36.8)	77 (59.7)	25 (20.5)	7 (15.9)	< 0.001b
Visible catheter colonization*, %	189 (62.2)	49 (38.0)	98 (80.3)	36 (81.8)	< 0.001b
Presence of catheter malfunction, %	43 (14.1)	2 (1.6)	27 (22.1)	11 (25.0)	< 0.001b
PDE leukocyte count, x1,000 cells/μL	1.2 [0.4–3.1]	1.2 [0.4–2.6]	1.1 [0.4–4.1]	1.1 [0.3–1.8]	0.65a
PDE neutrophil, %	83 [70–91]	87 [75–93]	80 [64–88]	86 [70–92]	0.004a
Preexisting exposure to antibiotics	127 (41.8)	56 (43.4)	48 (39.3)	20 (45.5)	0.71b
Season*, %					0.80b
Summer	55 (18.1)	22 (17.1)	23 (18.9)	10 (22.7)
Wet	189 (62.2)	78 (60.5)	77 (63.1)	27 (61.4)
Winter	60 (19.7)	29 (22.5)	22 (18.0)	7 (15.9)
Blood chemistries
Hemoglobin, g/dL	9.4 [8.1–10.7]	9.0 [7.6–10.4]	9.5 [8.3–10.7]	9.8 [8.9–11.0]	0.03a
Leukocyte count, x1,000 cells/μL	8.9 [6.6–11.4]	8.8 [6.6–11.5]	8.7 [6.3–11.2]	9.1 [7.1–11.1]	0.76a
Albumin, g/dL	2.6 [2.1–3.2]	2.6 [2.1–3.2]	2.6 [2.1–3.4]	2.8 [2.4–3.1]	0.77a
Potassium, mEq/L	3.5 [3.0–4.2]	3.5 [3.0–4.3]	3.5 [2.9–4.2]	3.4 [3.0–4.3]	0.88a
Fungal characteristics
Bacterial coinfection, %	24 (7.9)	12 (9.3)	6 (4.9)	5 (11.4)	0.27b
Positive galactomannan, %	154 (71.3)	57 (61.3)	70 (79.6)	22 (75.9)	0.02b
Onset to fungal identification (from peritonitis), days	10 [6–19]	10 [7–19]	11 [6–19]	8 [4–15]	0.37a
PD catheter treatment
Receiving PDC removal, %	271 (89.1)	114 (88.4)	110 (90.2)	38 (86.4)	0.77b
Onset to PDC removal (from peritonitis), days	8 [4–17]	7 [4–15]	9 [5–19]	7 [3–12]	0.24a
Onset to PDC removal (from FP diagnosis), days	5 [2–10]	5 [3–12]	5 [2–9]	4 [1–8]	0.20a
Immediate PDC removal (7 days from FP diagnosis)*, %	173 (56.9)	72 (55.8)	71 (58.2)	26 (59.1)	0.90b
Antifungal therapy
Receiving treatment, %	264 (86.8)	111 (86.1)	111 (91.0)	35 (79.6)	0.14b
Duration of treatment, days	14 [14–16]	14 [10–17]	14 [14–16]	14 [7–15]	0.08a
Adequate duration of treatment (14 days after PDC removal), %	156 (51.3)	69 (53.5)	63 (51.6)	19 (43.2)	0.49b
Amphotericin B, %	214 (70.4)	81 (62.8)	96 (78.7)	31 (70.5)	0.02b
Amphotericin B total dosage***, mg	700 [500–700]	700 [490–700]	700 [595–700]	700 [490–700]	0.19a
Amphotericin B***, mg/day	50 [40–50]	50 [35–50]	50 [40–50]	50 [45–50]	0.70a
Amphotericin B duration***, days	14 [14–14]	14 [14–14]	14 [14–14]	14 [14–14]	0.07a
Fluconazole, %	53 (17.4)	37 (28.7)	10 (8.2)	5 (11.4)	< 0.001b
Voriconazole, %	25 (8.2)	7 (5.4)	15 (12.3)	2 (4.6)	0.09b
Combination of antifungal agent*, %	47 (15.6)	15 (11.6)	24 (19.8)	7 (15.9)	0.20b

Abbreviations: FP, fungal peritonitis; PDC, peritoneal dialysis catheter, PDE, peritoneal dialysis effluent.

Categorical values are represented as number and percentages. Continuous values are represented as median [IQR].

*Total percentage is not equal to 100% due to rounding.

**Nine participants with mixed fungal peritonitis are excluded from analysis.

***Only patients who received Amphotericin B included.

aKruskal-Wallis test.

bPearson’s χ2 test.

cFisher’s exact test.

Treatment characteristics

Of interest, 11% (n = 33) and 13% (n = 40) of the fungal episodes did not receive PD catheter removal and antifungal medication, respectively. The average onset of PD catheter removal after the fungal diagnosis was 5 [2-10] days. The duration of antifungal therapy was 14 [14-16] days. Amphotericin B was the most common antifungal agent (70%), with an average dosage of 40 mg/day (0.7 mg/kg/day) and a duration of 14 days. It was combined with 5-flucytosine (5-FC) in 11 episodes (5%). Fluconazole, voriconazole, and itraconazole were used in 53 (17%), 25 (8%), and 8 (3%) episodes, respectively. Sequential therapy was prescribed in 32 episodes (11%), generally starting with amphotericin B and followed by fluconazole (n = 19), voriconazole (n = 9), or itraconazole (n = 4). Mold peritonitis was commonly treated with amphotericin B, whilst fluconazole was more frequently prescribed in yeast peritonitis (Table 2).

Fungal peritonitis and subsequent death

The median follow-up time of the participants was 12.0 [3.6–26.2] months that there was no significant difference among groups. The all-cause mortality rates of fungal peritonitis at 1, 3, 6, and 12 months after diagnosis of peritonitis were 11%, 23%, 31%, and 36%, respectively. Using multivariable Cox proportional hazards model analysis, every year increase in age and PD vintage were associated with 2% and 18% higher risks of death (HR = 1.02, 95%CI:1.00–1.04 and HR = 1.18, 95%CI 1.07–1.30), whilst every 1 gm/dL decrease in serum albumin and hemoglobin levels at baseline were associated with 68% and 22% greater risks of mortality (HR = 1.68, 95%CI:1.17–2.42 and HR = 1.22, 95%CI:1.08–1.38). Presences of catheter problems (catheter colonization and malfunction) were associated with lower risks of death (HR = 0.55, 95%CI 0.33–0.89 and HR = 0.52, 95%CI:0.32–0.83). A higher hazard of death was significantly associated with leaving the catheter in situ (HR = 6.15, 95%CI:2.86–13.23) and delaying catheter removal after the diagnosis of fungal peritonitis (HR = 1.56, 95%CI:1.00–2.44). Mortality was also associated with not receiving antifungal treatment (HR = 2.23, 95%CI:1.25–4.01) and duration of antifungal treatment less than 2 weeks (HR = 2.13, 95%CI:1.33–3.43). Each additional day of antifungal therapy beyond the minimum 14-day duration was associated with a 2% reduction in the risk of death (HR = 0.98, 95%CI:0.95–0.999). Each 100 mg/day increase in total dosage of triazole was associated with an 18% lower risk of death (HR = 0.82, 95%CI 0.69–0.97)(Table 3). Kaplan Meier curves for patient survival in each category of fungal peritonitis are demonstrated in Fig 3.

Table 3

Factors associated with mortality in patients with fungal peritonitis using univariable and multivariate analyses.

Variables	Unadjusted HR	95% CI	P value	Adjusted HR modela	95% CI	P value
Age per 1-year increment	1.02	1.01–1.04	0.008	1.02	1.00–1.04	0.03
Male gender	1.06	0.72–1.56	0.76	1.28	0.82–2.01	0.28
Diabetes	1.25	0.84–1.84	0.27	1.33	0.82–2.15	0.25
Employed state	0.69	0.46–1.03	0.07	0.70	0.44–1.12	0.14
Automated PD modality	2.68	0.85–8.46	0.09	1.18	0.26–5.31	0.83
PD vintage per 1-year increment	1.08	1.00–1.17	0.05	1.18	1.07–1.30	< 0.001
Clinical characteristics
Visible catheter colonization	0.66	0.44–0.97	0.03	0.55	0.33–0.89	0.01
Presence of catheter malfunction	0.62	0.42–0.91	0.02	0.52	0.32–0.83	0.006
PDE leukocyte count >1,090 cells/μL	1.11	0.75–1.63	0.61	1.17	0.75–1.83	0.49
PDE neutrophil count per 1% increment	1.01	1.00–1.02	0.08	1.01	1.00–1.02	0.11
Onset of FP diagnosis, 1 day incremental    from first peritonitis date	1.01	1.00–1.02	0.11	1.01	0.99–1.02	0.35
Blood chemistries
Hemoglobin per 1 g/dL decrement	1.13	1.03–1.25	0.01	1.22	1.08–1.38	0.001
Albumin per 1 g/dL decrement	1.86	1.38–2.51	< 0.001	1.68	1.17–2.42	0.005
Fungal characteristics (yeast as reference)
Hyaline mold	0.64	0.41–1.00	0.05	0.63	0.38–1.06	0.08
Non-Hyaline mold	1.31	0.79–2.19	0.30	1.21	0.70–2.16	0.52
PD catheter treatment
Not receiving PDC removal	3.20	1.73–5.93	< 0.001	6.15	2.86–13.23	< 0.001
Delay onset of PDC removal after FP diagnosis    (>7 days)	1.73	1.17–2.55	0.006	1.56	1.00–2.44	0.049
Onset of PDC removal, 1 day incremental from    date of FP diagnosis	1.01	1.00–1.03	0.08	1.01	1.00–1.03	0.14
Antifungal therapy
Not receiving treatment	3.67	2.38–5.66	< 0.001	2.23	1.25–4.01	0.007
Inadequate duration of treatment (after PDC    removal)	2.45	1.64–3.65	< 0.001	2.13	1.33–3.43	0.002
Duration of antifungal treatment per 1-day    increment from start of antifungal	0.97	0.94–0.99	0.003	0.98	0.95–0.999	0.04
Amphotericin B treatment	0.57	0.38–0.84	0.005	0.84	0.51–1.37	0.48
Amphotericin B dosage per 100 mg increment	0.93	0.88–0.98	0.004	0.96	0.90–1.01	0.13
Amphotericin B dosage per 10 mg/day increment	0.88	0.81–0.95	0.002	0.95	0.86–1.04	0.28
Amphotericin B duration per 1-day increment	0.97	0.95–0.99	0.03	0.98	0.96–1.01	0.24
Voriconazole treatment	0.39	0.14–1.06	0.07	0.40	0.13–1.29	0.13
Triazoles dosage per 1,000 mg increment	0.93	0.87–0.996	0.04	0.94	0.88–1.01	0.10
Triazole dosage per 100 mg/day increment	0.78	0.67–0.92	0.003	0.82	0.69–0.97	0.02
Triazole duration per 1-day increment	0.98	0.96–0.999	0.04	0.98	0.96–1.00	0.12
Combination of antifungal	0.66	0.36–1.20	0.17	0.59	0.28–1.24	0.16

Abbreviations: CI, confidence interval; FP, fungal peritonitis; HR, hazard ratio; PDC, peritoneal dialysis catheter, PDE, peritoneal dialysis effluent.

aAdjusted for age, gender, diabetes, employed state, PD vintage, hemoglobin, serum albumin, PDE leukocyte count > 1,090 cells/μL, and fungal type.

Fig 3

Kaplan-Meier curves comparing patient survival according to different types of fungal peritonitis.

In sensitivity analyses comparing combination vs. single and 2 weeks vs. > 2–4 (>2, >3, or >4) weeks of antifungal therapy, treatment duration of > 4 weeks was associated with significantly lower mortality than a 2-week course in univariable analysis. However, the results were no longer statistically significant after applying multivariable adjustments (S1 Table). Combination and single antifungal regimens were comparable with respect to patient survival.

The findings from this study differ somewhat from those of previous investigations. Specifically, the proportions of fungal peritonitis caused by hyaline molds (40%) and non-hyaline molds (15%) were relatively high, whilst the proportion due to Candida (35%) was relatively low compared with other published reports [2-17]. Generally, the reported prevalence of mold-associated peritonitis has varied from 0–32%, with the highest rate reported by the Australian and New Zealand Dialysis and Transplant (ANZDATA) Registry [10]. The reasons for the intriguingly high prevalence of mold peritonitis in our study are unclear but may have been related to climatic issues and the source of retrieved data used in this study. Thailand is located in a tropical area with hot and humid climates all year long, particularly in the wet season, usually accompanied by high precipitation rates and ambient temperatures. The contribution of climatic factors to the observed fungal peritonitis rates was supported by the high observed seasonal variations in fungal peritonitis, particularly during the wet season in both our study and the Australian study [19]. In the high-risk season, hot and humid climates may promote higher rates of skin perspiration, patient participation in outdoor activities, and the growth and virulence of environmental mold pathogens [19]. Additionally, our study involved surveillance registry data specifically designed to optimize capture of fastidious organisms, including environmental molds, through specialized media, conditions, and techniques. This may have augmented detection of filamentous mold infections in peritonitis episodes in more recent years that would have previously been categorized as culture-negative [20].

Our study further demonstrated that mold peritonitis, both hyaline and non-hyaline molds, was significantly more frequent than yeast peritonitis in patients presenting with catheter problems. The explanation may involve fungal properties, growth, and characteristics. Generally, mold colonies are more easily recognized by their profuse growth of hyphae. In addition, they often exhibit larger variably-colored, with hair-like diffuse edges, and central foci, while yeast colonies are white to off-white smaller translucent with defined edges and no foci, which is similar to bacterial colonies [21-23]. These unique manifestations are intriguing because previous studies have not shown these distinctions, possibly related to lower observed numbers of mold peritonitis with reduced statistical power [2,8,9,11,15]. This distinct feature might alert the physician to suspicion of fungal peritonitis, resulting in an early prescription of antifungal medication and performing PD catheter removal. Therefore, the presence of catheter problems was a protective factor on patients’ mortality in our study. Not surprisingly, a positive galactomannan test (a diagnostic marker for invasive fungal infections and PD-related peritonitis [24,25] and a prognostic marker for invasive aspergillosis in critical illness patients [26]) was detected less frequently in PDE from patients with yeast peritonitis (61%) than those with mold peritonitis (76–81%). Generally, yeasts contain a low amount of galactomannan in their cell walls, and Pneumocystis jiroveci and Candida spp. have absent galactomannan content in their cell walls. [24,25].

Although preexisting exposure to antibiotics was not different among 3 groups, almost half of each group (39–46%) had been received antibiotics in the past 3 months. Exposure to antibiotics has been known as one of the predictors of fungal peritonitis, particularly Candida infection. Unfortunately, only 5 episodes (1.5%) received antifungal prophylaxis, all of which were nystatin orally. According to the PDOPPS result, routine antifungal prophylaxis during antibiotic therapy varied considerably between countries, ranging from 7% in Japan and 23% in Thailand to 89% in Australia. However, most of the prophylaxis was employed in events with prolonged or broad-spectrum antibiotic uses, including peritonitis; the minority was used in all antibiotic courses, besides Australia [27]. Our finding supports the 2016 ISPD Peritonitis Guideline that “antifungal prophylaxis should be prescribed when PD patients receive all antibiotic courses to prevent fungal peritonitis (1B),” [18] particularly in countries with high prevalence fungal peritonitis.

Although the onset of fungal peritonitis diagnosis did not reach a statistical significance by both univariable and multivariable analyses, there were trends toward higher mortality in every extra day delay diagnosis of fungal peritonitis. Generally, the onset of fungal peritonitis is challenging to define in clinical practice, particularly in concomitant bacterial infection or secondary fungal infection cases. The fungus may colonize harmlessly inside the catheter. Nevertheless, if conditions are suitable, they can multiply and start to cause symptoms.

We found that a greater risk of death was associated with patients with older age, longer PD vintage, anemia, and hypoalbuminemia. Hypoalbuminemia has been revealed as a predictor for mortality in fungal peritonitis by Ram et al [9]. and as a negligible predictor by the other groups [11,14]. The previous studies did not find PD vintage and anemia to be risks factors of mortality in fungal peritonitis patients [11,14]. However, Nadeau-Fredette et al. found a trend of longer PD vintage in non-survived patients (2.5 and 5.0 years) [14]. These disparities are likely attributed to a small number of deaths in previous studies [9,11,14]. The results might be imprecise as the analyses were based on less than 30 deaths, whereas our analysis incorporated 70 (at 3 months) and 94 deaths (at 6 months). The sample size limitation might mask other possible interactions and associations among patient characteristics, laboratories, and clinical outcomes.

This study strongly supported the 2016 ISPD Peritonitis Guidelines’ recommendation for “immediate catheter removal when fungi are identified in PD effluent (1C)” [18] by demonstrating that leaving the catheter in situ or delaying catheter removal after the diagnosis of fungal peritonitis was strongly and independently associated with a higher mortality rate. A similar finding has been reported by previous studies [4,9,11]. Ram et al. [9] demonstrated that the mortality rate increases exponentially with increasingly delayed onset of the catheter removal, 19% (1 day), 67% (1 week), and 94% (1 month). However, the definition of delay onset used was varied across the literature [2-17]. Attempting to treat fungal peritonitis with the catheter in situ might leave an ongoing source of infection and impair the effectiveness of antifungals.

Of note, 11% of the fungal episodes in our study did not receive PD catheter removal despite the strong ISPD recommendation [18] of catheter removal in fungal peritonitis episodes soon after diagnosis. This finding may have reflected a lack of clinician appreciation of the virulence of mold peritonitis in Thailand. Since most Thai PD facilities (91%) have limited ability to culture filamentous mold [28], the attending nephrologists may also have had limited experience treating fungal peritonitis and limited access to infectious disease specialists. Moreover, some facilities might have had limited facility HD backup support, resulting in a reluctance to remove the PD catheter and subsequent deviation in practice from the ISPD Guideline recommendation. This will require further exploration.

Our study also found that longer durations of antifungal treatment beyond 2 weeks and higher dosages were associated with lower mortality rates. These findings support and extend the 2016 ISPD Peritonitis Guidelines recommendation that "treatment with an appropriate antifungal agent be continued for at least 2 weeks after catheter removal (2C). "[18] The optimal duration, dose, and choice of antifungal agents have not been previously established, probably due to previous studies’ sparsity and small sample sizes [18,29-31]. Our findings would guide the clinicians’ treatment decisions and prevent deleterious outcomes. A future revision of the guidelines concerning the finding of 2% decrease in mortality for every extra day beyond the minimum 14-day duration of antifungal medication is warranted.

The strengths of this study include its long length of follow-up (median 12.0, IQR 3.6–26.2 months), large sample size (304 fungal peritonitis episodes), and high cumulative number of death events (109 cases in 1 year), which helped to augment statistical power. However, some limitations also need to be highlighted. Firstly, participation in the surveillance registry was voluntary and not subjected to external audits. Consequently, the possibilities of ascertainment biases cannot be excluded. Despite adjusting for several demographic and clinical factors, the possibility of residual confounding also cannot be excluded. Secondly, the high detection rate of environmental mold raises a concern of specimen contamination during specimen sampling and handling in the registry data. However, the surveillance registry was well conducted, with orientation provided at all sites collecting and handling the specimens with strict aseptic technique. Of interest, colonization of the fungus was observed inside the catheter collected from most cases with filamentous fungus (80–82%), and subsequently, cultivation of the removed catheter confirmed its presence, thereby supporting its role as a genuine pathogen. In addition, the fungal cell wall in the PDE was tested in some cases to confirm the true positives. Finally, the observational design of this study means that causal inferences cannot be drawn.

Conclusions

In conclusion, mold peritonitis was more frequently associated with higher hemoglobin levels, presentations with catheter malfunction or intraluminal colonization, and a positive galactomannan test. Non-hyaline mold peritonitis was associated with the worst survival rates. Deviations from the 2016 ISPD Peritonitis Guideline recommendations concerning treatment duration and catheter removal timing were independently associated with higher mortality. Longer duration and higher daily dosage of antifungals were associated with lower mortality. Further investigation to identify more effective interventions that are specific to fungus type is warranted.

Kaplan-Meier curves comparing patient survival following treatment of fungal peritonitis with and without PD catheter removal.

(DOCX)

Click here for additional data file.

Sensitivity analyses of duration of antifungal therapies and mortality among patients with fungal peritonitis using univariable and multivariate analyses.

(DOCX)

Click here for additional data file.

(DOCX)

Click here for additional data file.

31 Jan 2022

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TK has received consultancy fees from VISTERRA as a country investigator and current recipient of the National Research Council of Thailand and received speaking honoraria from Astra Zeneca and Baxter Healthcare. JP has received speaking honoraria from Astra Zeneca, Baxter Healthcare, DaVita Healthcare Partners, Fresenius Medical Care, Dialysis Clinics Incorporated, Satellite Healthcare, and served as a Baxter consultant Healthcare, DaVita Healthcare Partners, Fresenius Medical Care, and LiberDi. DJ has previously received consultancy fees, research grants, speaker's honoraria, travel sponsorships from Baxter Healthcare and Fresenius Medical Care, consultancy fees from AstraZeneca, Bayer, and AWAK and speaker's honoraria from Ono and BI & Lilly, and travel sponsorships from Amgen. He is also supported by an Australian National Health and Medical Research Council (NHMRC) Leadership Investigator Grant. All other authors have no financial conflicts of interest to declare. All funders and pharmaceutical companies did not have any role in the study design, data collection, data analysis, data reporting, and the decision to submit for publication. This study was supported by Rachadaphiseksompot Endorsement Fund (CU-GRS_60_12_30_05), Chulalongkorn University, National Research Council of Thailand (156/2560), and Thailand Research Foundation (IRG5780017).

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Reviewer #1: Fungal Peritonitis is a dreaded complication of CAPD associated with technique failure, catheter removal, morbidity and mortality. This is a Multi centric study from Thailand whose experience with CAPD is huge given its PD First Policy. Multiple Risk factors were analysed well and my suggestions :

1. In the Materials and Methods section, a paragraph should be added about the specific specialised techniques used in isolation of these fastidious fungal pathogens. There is a passing mention about it in the Discussion section . But more details are required so that it can be corroborated by other centres

2. In the Discussion section , the first para can be omitted since it is a repetition of Results .

3. As a Recommendation based on this Paper do the Authors feel that additional week or two of anti fungal therapy will improve the survival? If they feel so, then it can be added as a recommendation

Reviewer #2: The study “Predictors and Outcomes of PD-Related Infections due to Filamentous Molds” is an interesting study. This cohort study included PD patients from the MycoPDICS database of Thailand who had fungal peritonitis between July 2015-June 2020. Authors conclude that Non-hyaline-mold peritonitis had worse survival. Longer duration and higher daily dosage of antifungal treatment were associated with better survival.

Comments:

1. The study included 304 fungal peritonitis episodes (yeasts n=133, hyaline molds n=122, and non-hyaline molds n=44) in 303 patients. A total sum of all episodes 133+122+44=299, not 304.

2. Authors have described the causative organism and outcomes of fungal peritonitis episodes only; however, it would be of interest to know the overall peritonitis rate and fungal peritonitis rate in that cohort of patients.

3. Authors have written that 11% (n=33) and 13% (n=40) of the fungal episodes did not receive PD catheter removal and antifungal medication, respectively. Overall, this percentage is a large number, can the authors mention that despite the recommendation of catheter removal in fungal peritonitis episodes soon after diagnosis, why catheters were not removed and antifungals were not given.

4. How many patients were treated with anti-fungal with catheters in situ and their success if any?

5. Each additional day of antifungal therapy beyond the minimum 14-day duration was associated with a 2% reduction in the risk of death (HR=0.98, 95%CI:0.95-0.999). Can authors identify, why these patients’ received antifungals beyond 14 days? was It a persistent ongoing fungal infection or something else? Can authors suggest an optimal duration of anti-fungal therapy?

6. Anti-fungal choices varied? Only 70% received Amphotericin- B, which was the basis of choosing other antifungals and combinations.

The only strength of the article is a large number of fungal episodes, and mortality predictors. Authors need to address the above mentioned comments to improve the manuscript.

**********

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Reviewer #1: Yes: Krishnaswamy Sampathkumar

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6 Apr 2022

Responses to Comments from Editor and Reviewers:

Reviewer #1

Fungal Peritonitis is a dreaded complication of CAPD associated with technique failure, catheter removal, morbidity and mortality. This is a Multi centric study from Thailand whose experience with CAPD is huge given its PD First Policy. Multiple Risk factors were analysed well and my suggestions :

1) In the Materials and Methods section, a paragraph should be added about the specific specialised techniques used in isolation of these fastidious fungal pathogens. There is a passing mention about it in the Discussion section . But more details are required so that it can be corroborated by other centres

Response: A paragraph about the specific specialised techniques used in the isolation of these fastidious fungal pathogens has been added to the MATERIALS AND METHODS section accordingly, as below.

“At the central laboratory, 3 bottles of 50 mL of PDE obtained from the submitted PD bags were centrifuged at 3,500g for 15 minutes, and the supernatants were subsequently discarded. The remaining solution (around 5 mL) was mixed up with pellet and injected into bacterial and mycobacterial broths/agars to exclude concomitant bacterial/mycobacterial infection, including Bactec Plus Aerobic/F, BACTEC Plus Anaerobic/F vials (Dun Laoghaire, Ireland), BACTEC MGIT 960 media, Ogawa medium slants, blood agar, MacConkey agar (Oxoid, Basing-stoke, UK), Chocolate agar (Oxoid, Basing-stoke, UK), and specific agar plates (as needed) for 5-7 days (bacteria) and 2 months (mycobacteria) at 37°C. For fungal culture, the pellet from another 50 mL of centrifuged PDE was streaked on Sabouraud dextrose agar (SDA) and specific agar plates (as needed), then incubated at 25°C and 37°C for 15-30 days. Yeast-form fungi were identified by API20c AUX kit (bioM´erieux, Marcy l’Etoile, France) based on biochemical reactions. Mold-form fungi were classified based on their sexual spores and conidia morphology.

Species were confirmed by molecular phylogeny using nucleotide sequences of internal transcribed spacer (ITS1/ITS4 primer; White et al., 1990) and large subunit region (5.8SR/LR7 primer; Vilgalys lab, Duke University) of the ribosomal RNA gene. The reaction mixture with fungal DNA was utilized as a positive control, and the reaction mixture without a template was used as a negative control. The experiments were repeated twice. The purified PCR products were then outsourced to Sanger sequencing service (First BASE Laboratories, Singapore Science Park II, Singapore). The sequencing results were subjected to BLASTN (National Center for Biotechnology Information Internet homepage) search against the GenBank database for homology identities. Antifungal susceptibility patterns of yeast and mold against common antifungal medications were assessed by Epsilometer test (bioMérieux, Marcy l’ Etoile, France) and broth dilution technique (according to the CLSI document M38-A2 protocol), respectively.”

2) In the Discussion section , the first para can be omitted since it is a repetition of Results.

Response: The first paragraph of the DISCUSSION section has been omitted accordingly.

3) As a Recommendation based on this Paper do the Authors feel that additional week or two of anti fungal therapy will improve the survival? If they feel so, then it can be added as a recommendation.

Response: The power of this study is not adequate to address this issue. The sensitivity analyses of 2 vs. > 2-4 (>2, >3, or >4) weeks and single vs. combination of antifungal therapy are shown in S1 Table and have been added to the RESULTS AND DISCUSSION section, as below.

“In sensitivity analyses comparing combination vs. single and 2 weeks vs. > 2-4 (>2, >3, or >4) weeks of antifungal therapy, treatment duration of > 4 weeks was associated with a significantly lower mortality than a 2-week course in univariable analysis. However, the results were no longer statistically significant after applying multivariable adjustments (S1 Table). Combination and single antifungal regimens were comparable with respect to patient survival.”

Reviewer #2

The study “Predictors and Outcomes of PD-Related Infections due to Filamentous Molds” is an interesting study. This cohort study included PD patients from the MycoPDICS database of Thailand who had fungal peritonitis between July 2015-June 2020. Authors conclude that Non-hyaline-mold peritonitis had worse survival. Longer duration and higher daily dosage of antifungal treatment were associated with better survival.

1) The study included 304 fungal peritonitis episodes (yeasts n=133, hyaline molds n=122, and non-hyaline molds n=44) in 303 patients. A total sum of all episodes 133+122+44=299, not 304.

Response: We sincerely apologize for the typographical errors in the ABSTRACT section. According to fungal morphology in wet smear, isolates included yeast (n=129, 42%), hyaline mold (n=122, 40%), non-hyaline mold (n=44, 15%), and mixed fungi (n=9, 3%). The ABSTRACT section has been revised accordingly as below.

“The study included 304 fungal peritonitis episodes (yeasts n=129, hyaline molds n=122, non-hyaline molds n=44, and mixed fungi n=9) in 303 patients.”

2) Authors have described the causative organism and outcomes of fungal peritonitis episodes only; however, it would be of interest to know the overall peritonitis rate and fungal peritonitis rate in that cohort of patients.

Response: Since the registry is voluntary, not all peritonitis episodes were submitted and reported to it. However, almost half of the reported centers (22 out of 48 centers) were participating in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS), a large prospective international cohort study in PD, in collaboration with the International Society for Peritoneal Dialysis (ISPD), which has recruited participants from many countries, including Thailand. We, therefore, have calculated the total and fungal peritonitis rates from the Thailand PDOPPS data during the same period. We found that the overall and fungal peritonitis rates were 0.24 and 0.02 episodes/patient-year, respectively.

3) Authors have written that 11% (n=33) and 13% (n=40) of the fungal episodes did not receive PD catheter removal and antifungal medication, respectively. Overall, this percentage is a large number, can the authors mention that despite the recommendation of catheter removal in fungal peritonitis episodes soon after diagnosis, why catheters were not removed and antifungals were not given.

Response: The uptake of the 2016 ISPD Peritonitis Guidelines recommendation [18] is low in Thailand, particularly in the rural and provincial areas. According to the PDOPPS study, center adherence to this guideline was generally suboptimal in Thailand. Example of such a practice deviations are that fungal prophylaxis during all antibiotic courses and exit-site prophylaxis were used in only 23% and 21% of facilities, despite this being level 1B and 1A recommendations by the ISPD guidelines, respectively [Boudville N et al. NDT 2019]. The following text has been added to the DISCUSSION section.

“Of note, 11% of the fungal episodes in our study did not receive PD catheter removal despite the strong ISPD recommendation [18] of catheter removal in fungal peritonitis episodes soon after diagnosis. This finding may have reflected a lack of clinician appreciation of the virulence of mold peritonitis in Thailand. Since most Thai PD facilities (91%) have limited ability to culture filamentous mold [28], the attending nephrologists may also have had limited experience treating fungal peritonitis and limited access to infectious disease specialists. Moreover, some facilities might have had limited facility HD backup support, resulting in a reluctance to remove the PD catheter and subsequent deviation in practice from the ISPD Guideline recommendation. This will require further exploration.”

4) How many patients were treated with antifungal with catheters in situ and their success if any?

Response: In 264 participants who received antifungal medication, there were 27 PD catheters left in-situ. The participants with PD catheters left in-situ tended to have a higher mortality at 3-month follow-up than participants who had their PD catheters removed (33% vs. 18%, p = 0.052). Ram et al. [19] demonstrated that the mortality rate increases exponentially with increasingly delayed onset of catheter removal: 19% (1 day), 67% (1 week), and 94% (1 month) [19]. Therefore, attempting to treat fungal peritonitis with the catheter in-situ might leave an ongoing source of infection and impair the effectiveness of antifungals, such that it should be discouraged.

5) Each additional day of antifungal therapy beyond the minimum 14-day duration was associated with a 2% reduction in the risk of death (HR=0.98, 95%CI:0.95-0.999). Can authors identify, why these patients' received antifungals beyond 14 days? was It a persistent ongoing fungal infection or something else? Can authors suggest an optimal duration of antifungal therapy?

Response: The basic approach to the duration and type of antifungal regimen used was determined according to the attending physician’s judgment. Although an antifungal treatment duration of > 4 weeks was significantly associated with lower mortality than a 2-week course in univariable analysis, the finding was no longer statistically significant after applying multivariable adjustments (S1 Table). This information has been added to the RESULTS AND DISCUSSION section, as below.

“In sensitivity analyses comparing combination vs. single and 2 weeks vs. > 2-4 (>2, >3, or >4) weeks of antifungal therapy, treatment duration of > 4 weeks was associated with a significantly lower mortality than a 2-week course in univariable analysis. However, the results were no longer statistically significant after applying multivariable adjustments (S1 Table). Combination and single antifungal regimens were comparable with respect to patient survival.”

6) Antifungal choices varied? Only 70% received Amphotericin- B, which was the basis of choosing other antifungals and combinations.

Response: The prescribed antifungal regimens in our study varied greatly in relation to the choice, duration, and dose of antifungal agent and the use of single or combined therapy, probably due to the lack of specific recommendations made in the 2016 ISPD Peritonitis Guidelines [18]. Moreover, the guidelines do not make specific treatment recommendations according to fungal type. Recommendations that are made are based on studies of Candida peritonitis. Therefore, in the absence of high certainty evidence and clear recommendations, the approach to treatment in this study was somewhat variable. Moreover, antifungal susceptibility tests are limited in Thailand; only 2 (9%) laboratories performed antimicrobial susceptibility tests for fungi [Kanjanabuch et al. Kidney Int Rep 2021]. Our result affirms the existence of treatment variation and demonstrates the association of such variations wtih mortality rate.

7) The only strength of the article is a large number of fungal episodes, and mortality predictors. Authors need to address the above mentioned comments to improve the manuscript.

Response: Thank you for your valuable comments.

Journal Requirements:

1) Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

2) Please provide additional details regarding participant consent.

3) We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match.

4) When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section.

5) Thank you for stating the following in the Acknowledgments/ Disclosure Section of your manuscript. Please note that funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

6) One of the noted authors is a group or consortium [Nephrology Society of Thailand]. In addition to naming the author group, please list the individual authors and affiliations within this group in the acknowledgments section of your manuscript. Please also indicate clearly a lead author for this group along with a contact email address.

Response: The manuscript’s format has been revised accordingly. Please revises the funding statement in the online submission form as shown below.

“This study was supported by the Thailand Science research and Innovation Fund Chulalongkorn University CU_FRB65_hea (19)_026_30_07, Chulalongkorn University, Thailand and the National Research Council of Thailand (156/2560). TK has received consultancy fees from VISTERRA as a country investigator and is a current recipient of the National Research Council of Thailand and received speaking honoraria from Astra Zeneca and Baxter Healthcare. JP has received speaking honoraria from Astra Zeneca, Baxter Healthcare, DaVita Healthcare Partners, Fresenius Medical Care, Dialysis Clinics Incorporated, Satellite Healthcare, and served as a Baxter consultant Healthcare, DaVita Healthcare Partners, Fresenius Medical Care, and LiberDi. DJ has previously received consultancy fees, research grants, speaker's honoraria, travel sponsorships from Baxter Healthcare and Fresenius Medical Care, consultancy fees from AstraZeneca, Bayer, and AWAK, and speaker's honoraria from Ono and BI & Lilly, and travel sponsorships from Amgen. He is also supported by an Australian National Health and Medical Research Council (NHMRC) Leadership Investigator Grant. All other authors have no financial conflicts of interest to declare. All funders and pharmaceutical companies did not have any role in the study design, data collection, data analysis, data reporting, and the decision to submit for publication.”

We hope that we have satisfactorily addressed the reviewers’ comments. Please do not hesitate to contact us if you require any further clarifications or information.

Thank you very much for your kind consideration.

Sincerely yours,

Prof. Talerngsak Kanjanabuch, MD

On behalf of the authors

Submitted filename: Responses to Reviewers MycoPDICS-28-Mar-2022.docx

Click here for additional data file.

10 May 2022

Predictors and outcomes of peritoneal dialysis-related infections due to filamentous molds (MycoPDICS)

PONE-D-21-30246R1

Dear Dr. Kanjanabuch,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Rebecca A Hall

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: (No Response)

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: (No Response)

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

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Reviewer #1: (No Response)

Reviewer #2: Yes

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Reviewer #1: (No Response)

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: (No Response)

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Reviewer #1: Yes: Dr.Krishnaswamy Sampathkumar

Reviewer #2: Yes: Narayan Prasad

16 May 2022

PONE-D-21-30246R1

Predictors and outcomes of peritoneal dialysis-related infections due to filamentous molds (MycoPDICS)

Dear Dr. Kanjanabuch:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Rebecca A Hall

Academic Editor

PLOS ONE