Detection of β-Lactamases among Bacteria Isolated from Stethoscopes

Abstract

β-lactamases are increasing in number and diversification of the group of enzymes is occurring that inactivates β-lactam type of antibacterial agents. The present study was essentially designed to detect β-lactamases among bacteria isolated from stethoscopes. The isolates were obtained from the Research Laboratory, Collegeof Medical LaboratoryScience,SudanUniversityofScienceand Technology (SUST). The study was carried out in the period from April to November 2014. The isolates were checked for purity by streaking on nutrient agar and simple stain. Re-identification was done by conventional bacteriological methods including colonial morphology, Gram’s stain and biochemical tests.β-lactamases were detected by iodometric method. Re-identification of the isolates revealed 13 Staphylococcus aureus, 5 S.saprophyticus, 38 S.epidermidis, 11 S.haemolyticus, 13 S.warneri, 6 S.lugdunensis, 7 S.hominis, 10 Escherichia coli, 11 Klebsiellapneumoniae, 11 Pseudomonasaeruginosa and 6 Proteus spp. Of the total bacterial isolates (n=131) investigated forβ-lactamases production, 127(96.9%) were β-lactamases producers. The rest 4(3.1%) were non β-lactamases producers. The study concluded that the production of β-lactamases amongst bacteria isolated from stethoscopes was very high (96.9%). Both Gram-positive and Gram-negative are β-lactamases producers. Regular detection of β-lactamases among clinical isolates recovered from hospitalized patients is highly recommended.