PCR Detection of Extended Spectrum β-Lactamase from Some Gram Negative Bacteria of Clinical Source

Abstract

Beta-lactamase-producing microorganisms present distinct challenges in health care systems around the world as a result of the  extensive utilization of broad-spectrum antibiotics. The objective of this research endeavor was to ascertain the antibiotic resistance  profile and presence of β-lactamase genes in Gram-negative bacteria that had been previously identified and collected from laboratory  work benches at the Department of Microbiology and Parasitology, UCH, located in Ibadan, South-West Nigeria. The Kirby-Bauer disc  diffusion method was used to assess antibiotic susceptibility on all the isolates, and the double disc synergy test was used to validate  extended spectrum beta-lactamase (ESBL) production phenotypically. The PCR techniques were used to detect β-lactamase genes. The  sample distribution of the forty clinical isolates were collected from the work benches and the distribution was: urine (17), blood (9),  wound (6), sputum (4), amniotic fluid (3) and tracheal aspirate (1). Klebsiella pneumoniae was the most prevalent organism with 17  isolates ( 42.5% ). Out of the 40 isolates that were obtained, 21 were ESBL producers and the distribution was as follows: Klebsiella  pneumoniae (9), Escherichia coli (6), Enterobacter cloacae (2), Enterobacter aerogenes (1), Pseudomonas aeruginosa (1), Acinetobacter  baumannii (1) and Hafnia alvei (1). The majority of the clinical isolates showed considerable resistance to antibiotic classes that were  tested, with amoxicillin-clavulanate showing the highest resistance rate at 65%. Out of all the ESBL producers, 35.3% had blaTEM, 29.4%  had blaCTX-M, 23.5% had blaSHV, and 11.8% had blaCMY. AmpC β-lactamases, Antibiotic resistance, Disc diffusion, Gram-negative  bacteria, Polymerase chain reaction.