Bacteremia caused by Elizabethkingia meningoseptica in a mechanically ventilated patient successfully treated with imipenem-cilastatin and ciprofloxacin.

Changhua, February 14, 2017

Dear editor

Elizabethkingia meningoseptica is ubiquitous in soil and water as well as in hospital environments,,. Thus, nosocomial outbreaks of E. meningoseptica can result from exposure to contaminated water sources or medical devices. Due to the therapeutic challenge resulting from multi-drug resistance, recognition and treatment of E. meningoseptica is of paramount importance for clinicians,. We report a case of bacteremia due to a multi-drug resistant E. meningoseptica in a patient who required assisted ventilation due to respiratory failure.

A 62-year-old male, who had had a history of oral cancer with operation and concurrent chemoradiotherapy, diabetes mellitus, bilateral vocal palsy, upper airway obstruction followed by tracheostomy and chronic obstructive pulmonary disease, developed cough with shortness of breath prior to admission. He was admitted to the intensive care ward because of impending respiratory failure. Ventilation support with Evita 4 (Dräger, Lubeck, Germany) was used, and he was transferred to the respiratory care center (RCC) for weaning twenty-one days later, because of fluctuations in his respiratory condition associated with underlying pulmonary problems. A new fever episode appeared on the 11th day after transfer to RCC (Figure 1). The lungs showed crackles on the right side. Laboratory analyses revealed a white blood cell count of 10,800 cells/ mm. The serum creatinine level was 2.3 mg/dL. The chest X-ray showed a new pneumonic patch over the left lower lobe. E. meningoseptica (2/2 sets) was identified by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (bioMerieux, Hazlewood, Mo.). An antimicrobial drug susceptibility test was conducted for E. meningoseptica by using the bioMérieux VITEK 2 system (bioMerieux, Hazlewood, MO.), and the minimum inhibitory concentration (MIC) was measured for each of the following antimicrobial drugs: piperacillin-tazobactam, cefotaxime, flomoxef, ceftazidime, cefepime, cefoperazone, amikacin, gentamicin, ciprofloxacin, levofloxacin, imipenem-cilastatin, meropenem, trimethoprim-sulfamethoxazole, doxycycline and colistin (Table 1). In addition, MIC results determined by the Epsilometer test (AB Biodisk, Sweden system) were: ciprofloxacin ≧4 μg/mL; levofloxacin ≧8 μg/mL; imipenem-cilastatin ≧16 μg/mL; meropenem ≧16 μg/mL; trimethoprim-sulfamethoxazole ≧4/ 76 μg/mL; and vancomycin ≧16 μg/mL. The patient received a combination of intravenous ciprofloxacin (200 mg every 12 hours) and imipenem-cilastatin (250 mg every 6 hours). His condition stabilized gradually and the follow-up chest X-ray showed improvement. Due to difficulty in weaning, he was transferred to a respiratory care ward after 42 days of hospitalization at RCC. No outbreak of E. meningoseptica infection was reported during the period of hospitalization at RCC. The follow-up of microbiological analyses for this patient did not show E. meningoseptica infection.

Figure 1

Timeline of the Elizabethkingia meningoseptica infection, serial chest X-ray images and serial antibiotics history

Table 1

Susceptibilities of this isolate to the antimicrobial agents

	E-test 3	VITEK 24	MIC interpretation criteria (μg/mL)
Antimicrobial agent 1	This isolate		S	I	R
Amikacin		≧64	≤ 16	32	≥ 64
Cefepime		≧32	≤ 8	16	≥ 32
Cefoperazone		≧64	≤ 16	32	≥ 64
Cefotaxime		≧32	≤ 8	16-32	≥ 32
Flomoxef		≧64	(pending)
Ceftazidime		≧32	≤ 8	16	≥ 32
Ciprofloxacin	≧4	≧4	≤ 1	2	≥ 4
Colistin		≧16	≤ 2	4	≥ 8
Doxycycline		≧16	≤ 4	8	≥ 16
Gentamicin		≧16	≤ 4	8	≥ 16
Imipenem	≧16	≧16	≤ 4	8	≥ 16
Levofloxacin	≧8	≧8	≤ 2	4	≥ 8
Meropenem		≧16	≤ 4	8	≥ 16
Minocycline		≧16	≤ 4	8	≥ 16
Piperacillin/tazobactam		≧128	≤ 16/4	32/4-64/4	≥ 32/4
Trimethoprim/sulfamethoxazole	≧4/76	≧4/76	≤ 2/38	-	≥ 4/76
Vancomycin2	≥ 16		≤ 2	4-8	≥ 16

Notes:The Clinical and Laboratory Standards Institute (CLSI) minimum inhibitory concentration (MIC) breakpoints for non-Enterobacteriaceae were applied for all antimicrobial agents except for vancomycin and flomoxef [Clinical and Laboratory Standards Institute. 2016. M100-S26: performance standards for antimicrobial susceptibility testing, 26th informational supplement. CLSI, Wayne, PA.]. The CLSI MIC breakpoint for Staphylococcus spp. was applied to vancomycin. Antimicrobial drug susceptibility test was conducted by using the Epsilometer test (AB Biodisk, Sweden system). Antimicrobial drug susceptibility test was conducted by using the bioMérieux VITEK 2 system (bioMerieux, Hazlewood, MO.). Abbreviation: CLSI: Clinical and Laboratory Standards Institute; I: intermediate; MIC: minimal inhibitory concentration; S: susceptible; R: resistant.

The appropriate choice of antibiotics for treatment of E. meningoseptica infection is difficult because optimal antimicrobial guidelines remain to be established,. Herein, the antimicrobial drug susceptibility test of this E. meningoseptica showed resistance to all the antibiotics, including trimethoprim-sulfamethoxazole and vancomycin. However, the bacteremia caused by E. meningoseptica was successfully treated in this case with a two-week administration of imipenem-cilastatin and ciprofloxacin. In terms of generalization, this case description is limited by the restricted number of clinical studies in the literature,, the lack of minimum inhibitory concentration breakpoints of antimicrobial agents to E. meningoseptica, and the paucity of 16S rRNA sequencing data due to the inability to perform a reliable 16S rRNA sequencing analysis without a valid positive control.

We suggest a combination therapy as an alternative for treatment of multi-drug resistant E. meningoseptica infection and undertaking active surveillance of E. meningoseptica infections because E. meningoseptica outbreaks could subsequently result from exposure to contaminated water sources or medical devices.