Objectives: This prospective study was carried out to look for the frequency of isolation of Citrobacter species from clinical specimens and study their antimicrobial susceptibility pattern.
Methods: Patients from whom Citrobacter species were isolated during routine diagnostic testing from January to December 2004 were included in the study. Isolates were identified by standard biochemical tests. Antimicrobial susceptibility testing was performed by disk diffusion method as per National Committee of Clinical Laboratory Standards (NCCLS) guidelines.
Results: Citrobacter species were isolated from a total of 205 patients. Infection was nosocomially acquired in 94.6% patients. One hundred eighty one (88.3%) patients had significant underlying illnesses. Culture yielded Citrobacter koseri in 185 (90.2%) and Citrobacter freundii in 20 (9.8%) patients. The distribution of isolates was as follows: urine (46.2%), respiratory tract (16.3%), blood (15.8%), pus (12.1%) and sterile body fluids (9.3%). Drug resistance was observed to be more in C. koseri as compared to C. freundii.
Conclusions: Citrobacter infections are often nosocomially acquired, seen in patients with significant underlying diseases and isolates are commonly drug-resistant. Adoption of hospital infection control practices and a good antibiotic policy may prevent their spread.