Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 12 2 2020 04 01 98 106 Elghar Soltani Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran AND Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Alka Hasani Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran AND Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Mohammad Ahangarzadeh Rezaee Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran AND Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Tahereh Pirzadeh Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Mahin Ahangar Oskouee Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Akbar Hasani Drug and Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Arezoo Noie Oskouie Department of Bacteriology and Virology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Ehsan Binesh Department of Infectious Disease, School of Medicine, Shahroud University of Medical Science, Shahroud, Iran 2019 10 17 2020 01 01 Background and Objectives: Trend analysis reveals that Klebsiella pneumoniae has witnessed a steep enhancement in the antibiotic resistance and virulence over the last few decades. The present investigation aimed at a comprehensive approach investigating antibiotic susceptibility including, extended spectrum beta-lactamase (ESBL) and AmpC β-lactamase (AmpC) resistance and the prevalence of virulence genes among the K. pneumoniae isolates. Materials and Methods: Sixty-one K. pneumoniae isolates were obtained from various clinical infections. Antimicrobial susceptibility was performed by disk diffusion method. The Mast® D68C test detected the presence of ESBLs and AmpCs phenotypically, and later presence of ESBL and AmpC genes was observed by polymerase chain reaction (PCR). Multiplex-PCR was performed to investigate various virulence genes. Results: Amongst 61 K. pneumoniae isolates, 59% were observed as ESBL and 14.7% as AmpC producers. All ESBL producers were positive for blaCTX-M-15, while blaCTX-M-14 was observed in 54.1% isolates. The frequency of AmpC genes was as follows: blaCMY-2 (60.7%) and blaDHA-1 (34.4%). The most frequent virulence genes were those encoding enterobactin and lipopolysaccharide. Presence of mrkD was associated with blaDHA-1 gene, while blaCMY-2 significantly (p≤0.05) correlated with the presence of iutA and rmpA virulence genes. blaDHA-1 positive isolates had urine as a significant source, while blaCMY-2 positive isolates were mainly collected from wound exudates (p≤0.05). Conclusion: Our results highlight that ESBL and AmpC production along with a plethora of virulence trait on K. pneumoniae should be adequately considered to assess its pathogenesis and antibiotic resistance. https://ijm.tums.ac.ir/index.php/ijm/article/view/2367 https://ijm.tums.ac.ir/index.php/ijm/article/download/2367/1228