Antimicrobial Resistance Pattern among Community-Acquired Gram-Positive and Gram-Negative Bacterial Bloodstream Isolates in India

Aim: To perform a retrospective analysis to assess the antimicrobial resistance pattern of grampositive- and negative- organisms involved in causing bloodstream infections. Antimicrobial susceptibility was performed using broth microdilutionmethodologies and results were interpreted using Clinical and Laboratory Standards Institute guidelines. Results: This study included 1825 gram-positive and 2986 gram-negative isolates. Twenty-nine percent (108/372) of the Staphylococcus aureus isolates were methicillin resistant with high rate of susceptibility for glycopeptides(>95%). Among the Enterococcus species, 12.1% (18/154) isolates were vancomycin resistant; also conferring resistance to linezolid(3.3%, 5/154). Most gramnegative organisms recorded high level resistance to cephalosporins (>70%), fluoroquinolones (>50%) and β-lactum agents (>65%). Extended-spectrum β-lactamases (ESBLs) were reported among 52.8% (346/655) of Escherichia coli; and of these, 5.3% (18/346) isolates conferred carbapenemresistance. Similarly, reduced carbapenemsusceptibility was reported against Acinetobacterspp. (62-83%; [ Acinetobacter baumannii, ~85%]) and Pseudomonas spp. (62%; [Pseudomonas aeroginosa, <50%]). Conclusion: Thus, glycopeptidesand carbapenemsretain high antimicrobial activity against most grampositive- and gramnegative- pathogens.