Assessment of the susceptibility of Klebsiella pneumoniae to beta-lactams

Abstract

Background and Objective: Klebsiella pneumoniae is a Gram negative bacilli causing infections related to health care. In recent years, it has become a multiressistente microorganism, because of the production spectrum beta-lactamase enzymes extended and carbapenemases. Therefore, the aim of this study was to evaluate the susceptibility profile of K. pneumoniae in relation to carbapenems; identifying carbapenemase production and to determine the susceptibility profile of the isolates compared to other β -lactams. Methods: This is research on naexperimental basis with quantitative and qualitative approach, which used 27 isolates from different clinical specimens ofpatients whit infection, assigned by reference laboratories. Prior to susceptibility testing, the saples were re-isolated on MacConckey Agar culture meddium and the plates were incubated with semeios at 37° C for 24 hours. Susceptibility testing to carbapenems and other beta-lactams were performed according to the method of Kirby-Bauer. The antibiotic disks used in the tests were amoxicillin - clavulanate, cefoxitin, cefotaxime, ceftazidime, cefepime, imipenem, meropenem and ertapenem. The test for the detection of the enzyme carbapenemase was performed by the use of antibiotics: meropenem, and ertapenem, by Modified Hodge test. Results:All isolates were susceptible to beta-lactam group of carbapenems and no production of carbapenemases, but 18.5 % produced extend-spectrum beta- lactamase extended spectrum and 40.7 % of the strains were resistant to other beta-lactams. Conclusion: The production of beta- lactamase extended spectrum was one of the main factors involved in resistance to antibiotics tested , but other resistance mechanisms were not identified possibly involved. KEY WORDS: Klebsiella pneumoniae. Disease Susceptibility. Beta-lactams.