Objectives: Cephalosporin resistance in Enterobacteriaceae has become an international concern. This article studies the distribution and trends of resistance of E. coli and Klebsiella species isolated from clinical specimens representing community-acquired infections.
Methods: E. coli, K. pneumoniae and K. oxytoca specimen strains were collected from patients presenting to three acute care hospitals in Lebanon. The study period extended from January 2010 to January 2011 and included patients presenting with community-acquired infections only. Automated microbiological system (VITEK 2) was used for identification and antimicrobial susceptibilities.
Results: Data from consecutive non-duplicate 589 E. coli, 54 K. pneumoniae and 40 K. oxytoca strains were collected of which 69.5%, 74.0% and 67.5% were susceptible to 3rd generation cephalosporins (3GC), respectively. Out of the 3GC-resistant E. coli strains, around 90% were susceptible to nitrofurantoin, 46% were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX) and 53% to ciprofloxacin. The patterns of antimicrobial susceptibility in the two Klebsiella species did not parallel those in the E. coli strains. Yet, the number of Klebsiella strains was much lower than that of E. coli. Of note is that the 3GC-resistant strains of both Klebsiella species were less susceptible to nitrofurantoin compared to the overall groups reaching a maximum of 30%. However, susceptibility to TMP/SMX was much higher reaching 79% and that of ciprofloxacin reaching 86%.
Conclusion: Clinical specimens of E. coli, Klebsiella pneumoniae and Klebsiella oxytoca, causing community-acquired infections in Lebanon showed that these organisms are significantly resistant to many antibiotics. These patterns of resistance were mainly to internationally recommended drugs for empiric treatment of community-acquired infections like community-acquired urinary tract infections (UTIs) and intra-abdominal infections. Therefore, continuous antimicrobial susceptibility surveillance is advisable to track emerging resistance in Enterobacteriaceae and national guidelines would be tailored accordingly.