ANTIBIOTIC SUSCEPTIBILITY OF CITROBACTER KOSERI IN NEONATAL INFECTIONS

Abstract

The background is that Citrobacter koseri is a recently recognized opportunistic pathogen of NICUs, which causes meningitis, brain abscesses and sepsis. It is intrinsically resistant to some antibiotics and the ability to develop ESBLs (Extended-Spectrum Beta-lactamases) makes it harder to treat. Methods: Antibiotic susceptibility profile of C. koseri isolated from neonatal infections was determined. Design: Cross-sectional study in a tertiary care NICU was performed for a period of 6 months. A total of 40 C. koseri isolates were obtained from newborns (0-28 days old) with blood, CSF, and urine samples. Gram staining, biochemical tests (catalase, oxidase, citrate, TSI) and API 20E system were used for identification. Susceptibility was determined by performing Kirby-Bauer disc diffusion on Mueller-Hinton agar as per CLSI 2024. 17 antibiotics belonging to 8 different classes were tested. The double-disc synergy test (DDST) was used to confirm the production of ESBL. Results: All isolates were meropenem (100%), imipenem (100%) and amikacin (95%) susceptible. The highest level of resistance was noted with ampicillin (100%), amoxicillin-clavulanate (85 %), cefazolin (82.5 %) and cefuroxime (77.5 %). 27.5% of the isolates were found to produce ESBL. Thirty-two and a half percent of isolates were multidrug resistant (MDR). Conclusions: C. koseri is reliably treated with carbapenems and amikacin in neonates. The emergence of ESBL and MDR is increasing the need for routine susceptibility testing. The empirical use of ampicillin or cephalosporins is not recommended