Characterization and Antibiotic Susceptibility Testing Of Acinetobacter Species in a Tertiary Care Hospital with Special Reference to NDM and OXA Genes
Background-Acinetobacter has emerged as a nosocomial pathogen. It was sensitive to most antibiotics, but today it exhibits resistance to most first line antibiotics. Carbapenems are the drug of choice for treating this infection but now resistance to carbapenems is being reported worldwide. Antibiotic susceptibility pattern of Acinetobacter may vary geographically and between various units of the same hospital at various point of time. The variation in antibiogram necessitates a periodic surveillance. Hence this study was conducted to understand the difference in phenotypic and genotypic methods by detection of OXA and NDM genes for accurate identification of antibiotic resistance, thus enabling successful implementation of antibiotic policy. METHODS- 70 isolates of Acinetobacter were collected and speciated. Antibiotic susceptibility pattern of all the isolates was determined and the carbapenem resistant isolates were subjected to real-time PCR for identification of NDM and OXA genes. RESULTS- A baumannii was the most common (74.3%) species, followed by A. lwoffii (25.7%). A. lwoffii was 100% sensitive to carbapenems. 50 strains of A. baumannii were carbapenems resistant and remaining were susceptible. In Carbapenem resistant A baumannii OXA 23 and OXA 51 are the most common gene detected by realtime PCR, followed by OXA 48 and OXA 58, while NDM was detected in 100% strains. DISCUSSION AND CONCLUSION- Knowledge of NDM and OXA producing Acinetobacter is imperative in formulating Institutional antibiotic stewardship program and infection control practices to control the spread of carbapenem resistant strains of Acinetobacterbaumanii. This information is extremely valuable for pharmaceutical companies towards development of newer antibiotics.