Genotyping of Pseudomonas aeruginosa strains as a multidrug resistant (MDR) bacterium and evaluating the prevalence of ESBLs and some virulence factors encoding genes by PFGE and ERIC-PCR methods

Document Type: Research article


1 Department of Microbiology, Faculty of Specialized Veterinary Science, Islamic Azad University, Science and Research Branch, Tehran, Iran.

2 Department of Microbiology, School of Basic Sciences, Saveh Branch, Islamic Azad University, Saveh, Iran.


Pseudomonas aeruginosa is an important multi-drug resistant (MDR) opportunistic bacterium. 102 strains of Pseudomonas aeruginosa equally isolated from human and cow milk were subjected to Multiplex-PCR for detection of ESBLs and exoenzymes of U, T, S, OprI, and OprL, Integrons class A encoding genes and genotyping by the ERIC-PCR and PFGE methods. The disc diffusion and E-test based on CLSI (Clinical and Laboratory Standards Institute) were performed to identify the antibiotics’ resistant strains. Exotoxin A encoding gene was detected in more than 90% of the studied strains, exoenzyme S prevalence in isolated samples from animal (cow milk) was negative and the frequency of Exo Y, Exo T, and Exo U were 25%, 68.6%, and 68.6%, respectively. The frequency of VEB and GES encoding genes in human strains were detected as 3.9% and 0 by Multiplex-PCR, respectively. The highest resistance was seen to Ampicillin and Cefepime (100%) while the lowest was observed to Amikacin (80.3%). E-Test results on human and animal strains showed complete resistance to Meropenem and Ampicillin, respectively. Dendrogram of ERIC-PCR method on human isolated samples revealed 22 different groups. Frequency of Integron I encoding gene was detected as 21.5% and 1.96% in human and animal strains, respectively. In general, the present study showed the high value of genetic diversity among isolates from animal and human samples with different progenitors, but the clones classified in one cluster revealed the same source of infection.


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