AmpC beta-lactamases in Klebsiella pneumoniae: An emerging threat to the paediatric patients.

OBJECTIVE

To determine the burden of AmpC beta-lactamase producing Klebsiella pneumoniae and its antimicrobial profile among paediatric patients.

METHODS

This cross-sectional study was conducted at the Microbiology Department of The Children's Hospital and the Institute of Child Health in Lahore, Pakistan, from May 2014 to April 2015, in which isolates of Klebsiella pneumoniae were screened by using the cefoxitin disc. Confirmation was done by inhibitor-based method using 400 micro grams of boronic acid dispensed on the cefoxitin discs. The zone sizes of cefoxitin with and without the boronic acid were compared. The antimicrobial susceptibility testing was performed using Kirby Bauer disc diffusion method.

RESULTS

Positive cultures yielded 585 Klebsiella pneumoniae out of which 220(37.6%) strains were AmpC beta-lactamase-positive on the basis of cefoxitin screening and 126(21.53%) were positive on the basis of inhibitor-based confirmatory method. Most of the infected patients 73(57.9%) were neonates. All AmpC beta-lactamase-producing strains were resistant to cephalosporins. They also exhibited resistance to ciprofloxacin 109(86.5%), amikacin 98(77.8%), levofloxacin 8(77.8%), cefoperazone-sulbactam 81(64.3%), piperacillin-tazobactam 82(65.1%), meropenem, 56(44.4%) and imipenem 32(25.4%).

CONCLUSIONS

Prompt identification of AmpC beta-lactamases using inhibitor-based confirmatory test can help reduce the burden of these pathogens.