Skin and soft-tissue infections associated with Aeromonas species in French Guiana: an 11-year retrospective study.

Editor

Aeromonas species are Gram‐negative bacilli, commonly found in salted and fresh water, food and soil. Skin and soft‐tissue infections (SSTIs) are frequent and have been reported in Australia, Asia and the Indian Ocean. However, data from South America are scarce. We investigated the exposures, clinical characteristics and antimicrobial susceptibilities of Aeromonads involved in SSTIs in French Guiana. We looked for risk factors of unfavourable outcome.

We retrospectively included all patients with skin or soft‐tissue infections and a positive culture with Aeromonas spp, seen in the Cayenne Hospital between 2007 and 2018.

A total of 81 patients were included. Clinical and epidemiological data are gathered in Table 1. Numbers of infections for each month of the year are presented in Fig. 1. The more frequent exposures were road trauma (n = 22) and snake bites (n = 16). Clinical presentations were often severe, including necrotizing fasciitis (n = 17) and abscesses (n = 15). Eleven patients required amputation.

Table 1

Clinical characteristics of the 81 patients with skin and soft‐tissue infections (SSTIs) caused by Aeromonas species, French Guiana, 2007‐2018

Characteristics	No. (%) of patients. n = 81
Age (years)	40 [7‐80]
Male gender	64 (79)
Female gender	17 (21)
Geographic origin
Cayenne metropolitan area	44 (54)
Upper Maroni	25 (31)
Coastal region	8 (10)
Other	4 (5)
Underlying condition
Diabetes mellitus	10 (12)
Organ failure	7 (9)
Wound location
Lower limb	58 (72)
Upper limb	12 (15)
Chest	5 (6)
Head	5 (6)
Abdomen	1 (1)
Exposure
Road trauma	22 (27)
Snake bite	16 (20)
Chronic wound	9 (11)
Water exposure	8 (10)
Burn	7 (9)
Metallic foreign object	7 (9)
Firearm	6 (7)
Stingray stabbing	3 (4)
Unknown	3 (4)
Wood foreign object	2 (2)
Dog bite	1(1)
Clinical presentation
Localized wound infection	36 (44)
Necrotizing fasciitis	17 (21)
Abscess	15 (19)
Cellulitis	8 (10)
Infected ulcer	5 (6)
Organism
A. hydrophila	76 (94)
A. caviae	4 (5)
A. jandaei	1 (1)
Type of infection
Polymicrobial infection	63 (79)
Monomicrobial infection	18 (21)
Management
Antibiotic therapy only	42 (52)
Wound debridement	28 (35)
Amputation	11 (14)
Issue
Complete healing	60 (74)
Amputation	11 (14)
Evacuation to mainland France	6 (7)
Death	2 (3)
Chronic evolution	2 (3)

Figure 1

Seasonal variations of infections caused by Aeromonas spp in French Guiana, 2007–2018.

Antibiotic resistance profile was known for 77 patients (95%). Most strains were resistant to ticarcillin (72%). Less than 5% were resistant to ciprofloxacin, imipenem or gentamicin. None were resistant to ceftazidime or amikacin.

Aeromonas hydrophila was the most common pathogen (n = 76, 94%). The majority of patients had polymicrobial infections, mostly with enterobacteriae (n = 27, 33%) and Staphylococcus aureus (n = 15, 19%). One half of monomicrobial infections (n = 18, 22%) were caused by snake bites.

Concerning the outcome, two patients died, including a 61‐year‐old woman with A. hydrophila bacteraemia and a 71‐year‐old diabetic woman with a necrotizing fasciitis growing A. hydrophila and Klebsiella pneumonia. They both received amoxicillin–clavulanate though both germs were resistant. In multivariate analysis, the presence of burn as a route of entry (7 patients, 9%) was the only factor associated with unfavourable outcome (OR 6.54, 95% CI [1.13‐37.95]).

As in previous studies, A. hydrophila was the most common species responsible for skin and soft‐tissue infection and infections occurred mostly during the rainy season. , The predominance of men and lower limbs is common in Aeromonads and should be linked to the role of outdoor activities as routes of entry. Among these exposures, burns were incriminated in 7 patients, possibly due to the use of contaminated water in primary care against burns. Aeromonas spp are a classic component of the oral microbiota of snakes, and we report here the largest series of Aeromonads infection after snake bite (n = 16, 20%).

Concerning clinical features, the proportion of necrotizing fasciitis (n = 17, 21%) was higher than in most previous studies, excepting a report of Aeromonads infections after a tsunami in Thailand. This frequent severity could be explained by a delay in treatment due to a lack of healthcare access in remote areas of French Guiana. Though previous studies reported an important proportion of immunocompromised patients, , such a feature was not observed in our cohort. Thus, Aeromonads infections should also be expected in healthy young men performing at‐risk outdoor activities.

In multivariate analysis, burns were associated with unfavourable issue, mirroring previous case reports of high mortality in burned patients infected with Aeromonads. The only two deaths occurred when antibiotics were not adapted to antibiograms. These results highlight the importance of antibiotic stewardship in circumstances of burns, waterborne or telluric contaminations. Antibiotics covering Aeromonas and frequent co‐pathogens should then be contemplated (third‐generation cephalosporin or fluoroquinolone). Patients with burns in rainforest areas should be closely monitored due to the high risk of unfavourable outcome.