The Antibiotic Resistance Pattern in Citrobacter Species: an Emerging Nosocomial Pathogen in a Tertiary Care Hospital

Members of genus, Citrobacter, a gram negative, non sporing rod which belongs to the family, Enterobacteriaceae are emerging as important nosocomial pathogens. In health care setting Citrobacter species have become an increasing cause of concern as they are multi drug resistant and associated with high mortality between 30–60%. Recently there has been an increase in isolation of Citrobacter species from various clinical specimens from different patients in our hospital. The current study was done to find out the antibiotic sensitivity pattern of Citrobacter species from various clinical specimens.

Study was conducted in Vydehi institute of medical sciences and research centre, Bangalore over a period of 2 years 3 months. Samples were collected from patients in accordance with standard protocols. Citrobacter species were isolated and identified by conventional methods. Antibiotic susceptibility of the isolates was done by disc diffusion method according to clinical and laboratory standards institute (CLSI) guidelines.

Out of 128 isolates of Citrobacter, majority were isolated from pus (32.81%) and sputum (32.81%) followed by tracheal aspirate (12.5%), blood (10.15%), catheter tip (7.03%), throat swab (2.34%), conjunctival swab (0.78%), pleural fluid (0.78%), vaginal swab (0.78%). Citrobacter koseri was the predominant species (70.31%) isolated. Antibiogram of Citrobacter isolates revealed that effective agent against Citrobacter isolates was imipenem (85.8%). Among 128 isolates one Citrobacter koseri isolate was sensitive to all drugs, 5 Citrobacter koseri isolates were resistant to all drugs and 12 Citrobacter koseri isolates were sensitive only to imipenem.

The Citrobacter isolates resistant to multiple antimicrobial agents have emerged, including strains resistant to imipenem, making it an emerging nosocomial pathogen.