Extended Spectrum β-Lactamases Producing Klebsiella pneumoniae from the Neonatal Intensive Care Unit at the University Teaching Hospital in Lusaka, Zambia

Abstract

Klebsiella pneumoniae is one of the major causes of blood-stream infections in neonatal intensive care units. Treatment has been a challenge due to the development of multidrug resistant strains, which are mainly attributed to the ability of the organism to produce extended spectrum β-lactamases that confer resistance to second and third generation cephalosporins. This laboratory-based cross-sectional study was aimed at determining the extent of extended spectrum β-lactamase production among invasive K. pneumoniae isolates from blood culture specimens at the University Teaching Hospital in Lusaka. The production of the extended spectrum β-lactamases was detected using the combination disc method, and by detecting genes encoding extended spectrum β-lactamases using Polymerase Chain Reaction. The drug resistance profile was determined using the Kirby-Bauer disc diffusion method against tetracycline, chloramphenicol, amikacin, gentamicin, co-trimoxazole, ciprofloxacin, cefotaxime, ceftazidime, cefpodoxime and imipenem. All the 45 isolates were found to be ESBL producers, and out of these 33/45 (73%) were found to have detectable ESBL-encoding genes: BlaSHV (27/45, 60%) and BlaTEM (6/45, 13%). No BlaCTX-Mgene was detected. Antimicrobial susceptibility testing revealed a high frequency of antimicrobial resistance: cefotaxime (100%), ceftazidime (100%), cefpodoxime (100%), co-trimoxazole (100%), tetracycline (100%),gentamycin (97.8%) and chloramphenicol (97.8%), and ciprofloxacin (95.6%). The antimicrobial resistance profile indicated that all the isolates were multidrug resistant, with each being resistant to at least 5 antibiotics. However, all the isolates were susceptible to amikacin andimipenem. In conclusion, there is high prevalence extended spectrum β-lactamases producing invasive K. pneumoniae isolates, which are also multidrug resistant, in the intensive care unit at the University Teaching Hospital. It is, therefore, recommended that all K. pneumoniae isolates should be screened for production of extended spectrum β-lactamases, and that infection control measures should be instituted at the University Teaching Hospital to curtail this problem.