Role of Imipenem-resistant metallo-beta-lactamase positive pseudomonas aeruginosa carriers in nosocomial infections

BACKGROUND: Imipenem-resistant metallo-beta-lactamase Positive Pseudomonas aeruginosa (IR-MBLP-PA) infections occur as outbreaks and epidemics with a potential to spread within and between hospitals and intercontinentally. Limited data is available on IR-MBLP-PA carriers and their role as source and/or reservoir of nosocomial infection. OBJECTIVES: Detection and antibiogram typing of IR-MBLP-PA from healthy healthcare workers (HCW) from different areas of hospital and to assess role of carriers as source and/or reservoir of nosocomial infections. MATERIAL AND METHODS: Specimens from 200 HCWs [ICUs (120), General wards (40) and OPDs (40)] were collected from axilla, hands, stool and throat and processed by standard laboratory procedures. IR-MBLP-PA detection is done by IMIPENEM+EDTA combined disc test. Antibiogram typing is done. Association of carriers with clinical cases is done by IR-MBLP-PA with identical antibiogram type from carriers and cases. Distribution of carriers was assessed by Chi-square test. RESULTS: Incidence of P. aeruginosa and IR-MBLP-PA carriers among HCWs was 25%, 3.21% in ICUs, 10% from general wards and 0% from OPDs. A total of five IR-MBLP-PA antibiogram types were observed from four carriers and none from general wards and OPDs. Distribution of P. aeruginosa and IR-MBLP-PA carriers in different areas of hospital was not statistically significant with P values of 0.058 and 0.76, respectively. CONCLUSIONS: Role of IR-MBLP-PA carriers as source and/or reservoirs of infections could not be assessed with certainty; however, the possibility cannot be ruled out. Periodic carrier studies in targeted high risk areas of hospital should be undertaken.