Surveillance Report (Atlas) on Antimicrobial Activity of Aztreonam-avibactam and Comparator Agents Tested against MBL-positive Carbapenem-resistant Klebsiella Spp. Isolated From India (2022)

INTRODUCTION: Antimicrobial resistance is a growing concern in India, with increasing resistance to last resort antibiotics. Carbapenems are generally considered the drugs of choice for serious infections due to Gram-negative bacteria including Enterobacterales, however their use has substantially increased the spread of carbapenem resistance.(1) Klebsiella spp is one of the most prevalent bacteria that cause nosocomial infections, particularly in critically ill patients in the intensive care unit (ICU).(2) OBJECTIVES: This ATLAS (The Antimicrobial Testing Leadership and Surveillance) report analyses the susceptibility for aztreonam-avibactam and comparator agents among MBL-positive Klebsiella spp. isolates and further analyses the carbapenemase genes. MATERIALS AND METHODS: Non-duplicate clinical isolates of Klebsiella spp. (n=504) were collected from ten Indian tertiary care centres across the country. Susceptibility was performed at an IHMA (International Health Management Associates) laboratory using broth microdilution method according to CLSI guidelines (EUCAST for Aztreonam avibactam and Colistin). RESULTS: Among carbapenem-resistant (CR) Klebsiella spp. (n=280; 56%), 186 (66%) were MBL-positive Molecular analysis of CR isolates for MBL using multiplex PCR assays. Below are the in vitro activities of the commonly used antibiotics against the MBL-positive CR isolates. DISCUSSIONS/CONCLUSIONS: The current data highlight the potent activity of aztreonam–avibactam against MBL-positive K. pneumoniae. Among Klebsiella spp. co production of NDM with OXA-48 is the predominant carbapenemase mechanism followed by NDM. Among the comparators, tigecycline followed by colistin showed the highest susceptibilities however tigecycline attains very low plasma concentrations and is not licensed for use in blood stream infections, while the use of colistin may be limited by the lack of CLSI susceptibility breakpoints and safety concerns. As therapeutic options to treat serious infections caused by MBL carriers are presently extremely limited, aztreonam–avibactam represents a potentially effective option.