A comparison of the antimicrobial activity of meropenem and selected broad-spectrum antimicrobials tested against multi-drug resistant Gram-negative bacilli including bacteraemic Salmonella spp.:: Initial studies for the MYSTIC programme in India

The evolution in India of multi-drug resistant pathogens possessing extended-spectrum beta-lactamases (ESBLs) threatens to compromise the clinical utility of third-generation cephalosporims and monobactams. Using selected resistant strains from a recent Indian 10 centre surveillance study that measured the prevailing incidence of resistance to P-lactam antibiotics, the potential clinical utility of meropenem was assessed against nine other antimicrobial agents. A total of 212 Gram-negative bacilli were tested, of which 125 were confirmed by reference methods to be ESBL-producers. Meropenem was the most active of the test antimicrobials against these strains and the rank order of susceptibility was meropenem (99.1% susceptible) > piperacillin/tazobactam (76.9%) > ciprofloxacin (42.5%) > antinoglycosides (34.4-39.6%) = other beta-lactarris (30.0-39.6%). Of the tested strains only two (Acinetobacter spp. and Pseudomonas putida) showed an intermediate susceptibility (8 mg/l) to meropenem. Of the 57 tested strains of Salmonella spp., three had an ESBL phenotype, confirmed two of the strains. This study confirms the high levels of resistance to beta-lactams agents in India reported elsewhere and also demonstrates, for Escherichia coli and Klebsiella spp., high levels of coresistance between the tested beta-lactam agents and ciprofloxacin and the aminoglycosides, gentamicin and tobramycin. However, carbapenems such as meropenem, remain a therapeutic option. (C) 2002 Published by Elsevier Science B.V. and International Society of Chemotherapy.