Phenotypic and genotypic detection of -lactams resistance in Klebsiella species from Egyptian hospitals revealed carbapenem resistance by OXA and NDM genes

The β-lactams are frequently used antibiotics and are essential in treatment of serious bacterial infections. The emergence of β-lactamases has been an ongoing serious therapeutic problem. To overcome this problem, scientists utilized several β-lactamases inhibitors such as clavulanic acid and tazobactam that are used in combination with antibiotics. However, pathogenic bacteria have acquired additional mechanisms of resistance such as the acquisition of extended spectrum beta-lactamases (ESBL) and carbapenemases that cannot be inhibited by current inhibitors. Carbapenem-resistant Enterobacteriaceae (CRE) has become an international health threat. In the present work, 100 clinical Klebsiella strains were isolated, identified, and their antibiotic profiles were determined by the disc diffusion method. β-lactam resistance was evaluated using phenotypic and genotypic methods. More than 50% of the Klebsiella isolates exhibited resistance to tetracyclin, ceftriaxone, (pipracillin/tazobactam), azetreonam, ofloxacin, cefepime and cefoperazone/sulbactam. Klebsiella isolates were less resistant to gentamicin (32.4%) and amikacin (14.7%). Few isolates were resistant to meropenem and imipenem (6.86%). Among the 100 clinical isolates, 50% were ESBL producers and 32% were AmpC producers. The 7 imipenem resistant isolates were carbapenemase producers. PCR showed that carbapenem resistance may be due to NDM gene that was present in 43% of the isolates and OXA gene that was found in 28% of the isolates. KPC genes were not detected in any of the isolates. Antibiotic resistance is a worldwide problem that poses a major threat to therapeutic efficacy of available antibiotics, including carbapenem. Determination of causes of resistance is essential for better treatment options. Key words: Klebsiella, beta-lactams, ESBLs, carbapenem-resistant, NDM, OXA, antibiotic resistance