Epidemiology and antimicrobial susceptibility profiles of aerobic and facultative Gram-negative bacilli isolated from patients with intra-abdominal infections in the Asia-Pacific region: 2008 results from SMART (Study for Monitoring Antimicrobial Resistance Trends)

Abstract

During 2008, the Study for Monitoring Antimicrobial Resistance Trends (SMART) collected 2370 unique aerobic and facultative Gram-negative bacilli associated with intra-abdominal infections (IAIs) from 32 centres in 11 countries in the Asia-Pacific region and tested their in vitro susceptibility to 12 antimicrobial agents using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. Enterobacteriaceae comprised 88.1% of the isolates, of which Escherichia coli was the most commonly isolated species (47.2%). Very low susceptibility rates to ampicillin/sulbactam were noted, particularly from China (27.4%) and India (28.8%). High rates of extended-spectrum β-lactamase (ESBL)-producing E. coli and Klebsiella pneumoniae were observed in China (59.1% and 34.4%, respectively), India (61.2% and 46.8%, respectively) and Thailand (53.0% and 23.1%, respectively), particularly those causing hospital-associated IAIs. The persistently high rates of E. coli isolates non-susceptible to fluoroquinolones were alarming, especially in Thailand (>50%), China (≥70%) and India (>80%). Twenty percent of ESBL-producing E. coli and 10% of ESBL-producing K. pneumoniae were susceptible to ceftazidime based on the CLSI 2010 guidelines. Carbapenems were the most reliably active in vitro against Enterobacteriaceae. However, isolates of ESBL-producing K. pneumoniae exhibiting non-susceptibility to ertapenem (7.5%) and imipenem (1.9%) emerged, particularly from community-associated IAIs and those isolated from patients in intensive care units. Regular updates of epidemiology and antimicrobial resistance profiles of pathogens associated with IAIs as well as regional treatment guidelines are necessary to ensure optimal antimicrobial therapy.