IN VITRO TESTING OF TIGECYCLINE AMONG THE CLINICALLY SIGNIFICANT BACTERIAL ISOLATES OBTAINED FROM BLOOD STREAM INFECTION IN A TERTIARY CARE CENTRE OF EASTERN NEPAL

BACKGROUND Multidrug resistant organisms like methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant enterococci (VRE) and extended spectrum beta lactamase (ESBL) producing organisms are being encountered as the causative agents of blood stream infection. Tigecycline has been designed to overcome resistant mechanisms of these agents. Therefore, this study was carried out to identify Methicillin resistant Staphylococcus aureus, vancomycin resistant enterococci and extended spectrum beta lactamase producing organisms in blood culture isolates at Microbiology Laboratory and to determine the antimicrobial susceptibility of tigecycline against them. MATERIALS AND METHODS A descriptive study was carried out in Microbiology Laboratory, BP Koirala Institute of Health Sciences, Dharan, Nepal. Altogether 125 Staphylococcus aureus, 60 Enterococci and 150 Gram Negative Bacteria (GNB) were obtained during 1 year period (July 2011 June 2012). Laboratory detection of MRSA, VRE and ESBL producers and antimicrobial testing of tigecycline were done following standard protocol. RESULTS Overall analysis determined 24% were MRSA, 3% VRE and 47% of ESBL producing bacterial isolates respectively. Tigecycline showed 100% sensitivity among MRSA and VRE, whereas 12.6% of ESBL producing GNB were resistant to tigecycline. CONCLUSION MRSA, VRE and ESBL producing bacteria are identified in blood culture isolates at BPKIHS. Tigecycline demonstrated the excellent antimicrobial activity against MRSA and VRE, but the decreased performance on gram negative isolates including ESBL producers which is indeed another alarming issue for further use of new drug.