Background: Klebsiella pneumoniae can be defined as one of the clinically relevant pathogens that is a common cause of community-acquired and hospital-acquired urinary tract infections (UTI). Objective: The current study was conducted to investigate most common members of 5 classes of efflux pumps among K. Pneumonia isolates. Methodology: K. Pneumonia isolates was diagnosed on EMB and confirmed by tyrB gene. Antibiotic susceptibility test has been done based on the CLSI-2019. Efflux pumps genes were examined via PCR. Results: All isolates were high resist to ceftazidime, Amoxicillin, cefotaxime, ceftriaxone, Cefixime, cefepime, streptomycin and trimethoprime. Moderate resistance were showed to nitrofurantion, Aztreonam, Kanamycin, Cefoxitin, Gentamycine and Tobramycine. Low resistance was exhibited to Ciprofloxacine, Azithromycin, Doxycycline, piperacillin, Nalidixic acid, Imipenem and Amikacine. High sensitivity were exploited to Levofloxacine, ofloxacine, Meropenem and Netilamicin Concern antibiotic resistance patterns PDR, XDR and MDR), the results revealed that (10%) isolates were non-MDR while MDR compile (90%). Results of molecular investigation of efflux pumps in K pneumonia revealed that, AcrAB-TolC, AcrAD-TolC and AcrFE-TolC genes, EmrAB-TolC, EmrD and MdfA, EmrE, YnfA and TehA, MacAB-TolC and MdlAB-TolC, MdtK and DinF) genes were investigated for K. pneumoniae. Results of biofilm formation revealed that 100% were biofilm former (40% weak biofilm, 44% moderate and 16% strong biofilm former). Conclusion: The study concludes that, all efflux pumps may be highly associated with resistance to penicillins and cephalosporins and moderately with streptomycin, trimethoprime, nitrofuraniton, Aztreonam, Kanamycin. Additionally, biofilm formation was highly related to presence of studied pumps.
