Prevalence and risk factors for colonisation with extended spectrum β-lactamase producing enterobacteriacae vis-à-vis usage of antimicrobials

Purpose: A point prevalence study was carried out in a teaching hospital in Assam to determine the prevalence, sensitivity profile and risk factors for acquisition of extended spectrum β-lactamase (ESBL) producing enterobacteriacae vis- -vis amount and pattern of antibiotic use. Materials and Methods: ESBL was detected by double disc synergy method. Defined daily dose and bed-days were calculated. Result: Colonisation rate of ESBL producing enterobacteriacae ranged from 14% (n=73) in medicine to the highest 41% (n=29) in orthopaedic with an intermediate 23% (n=80) in surgery. Presence of ESBL was found to be strongly associated with resistance to specific classes of antimicrobials. Exposure to cefotaxime and gentamicin, and surgery were risk factors for acquiring ESBL producing enterobacteriacae. Non-ESBL producing community isolates were found to be considerably more sensitive to different antibiotics with no resistance detected to trimethoprim, co-trimoxazole, ciprofloxacin and aminoglycosides. Conclusion: The study confirms the role of certain ′high risk′ antimicrobials in acquisition of ESBL producing Enterobacteriaceae and shows that periodic cohort studies could be an effective strategy in surveillance of antimicrobial resistance in hospitals of resource poor countries to inform antibiotic policy and treatment guidelines.