Phenotypic and molecular characterization of fluoroquinolone resistant Pseudomonas aeruginosa isolates in Palestine

Fluoroquinolones are important antimicrobial agents for the treatment of Pseudomonas infections. A total of 11 isolates of P. aeruginosa were collected from different clinical samples from different medical centers in the North West Bank-Palestine during 2017. In this study, resistance to fluoroquinolones and secretions of β-lactamases were detected by phenotypic methods, while presence of β-lactamase gene sequences and other virulence factors were detected by PCR technique. PCR product for gyrA, parC and parE genes were sequenced for further analyses. The phylogenetic analyses, population diversity indices and haplotypes determination were conducted using computer programs MEGA version 6, DnaSP 5.1001 and median-joining algorithm in the program Network 5, respectively. Results of this study showed that the MIC for ciprofloxacin and norfloxacin had a range of 32-256 µg/ml. In addition, all isolates carried either exoT or exoT and exoY genes, different β-lactamase genes and 82% of these isolates harbored class 1 integrons. Analyses of the gyrA, parC and parE sequences were found to be polymorphic, had high haplotype diversity (0.945-0.982), low nucleotide diversity (0.01225-0.02001) and number of haplotypes were 9 for each gyrA and parE genes and 10 haplotypes for parC gene. The founder haplotypes being Hap-1 (18%), Hap-2 (27.3%) and Hap-6 (9.1%) for gyrA, parC and parE genes, respectively. Two of ParE haplotypes were detected as indel haplotypes. The Median-joining- (MJ) networks constructed from haplotypes of these genes showed a star-like expansion. The neutrality tests (Tajima’s D test and Fu’s Fs test) for these genes showed negative values. Palestinian fluoroquinolone resistant P. aeruginosa strains showed high MIC level for fluoroquinolones, β-lactamase producers, carried type III secretion exotoxin-encoding genes, most of them had integrase I gene and had high level of mutations in QRDR regions in gyrA, parC and parE genes. All these factors may play an important role in the invasiveness of these strains and make them difficult to treat. Isolation of these strains from different medical centers, indicate the need for a strict application of infection control measures in Medical centers in the North West Bank-Palestine that aim to reduce expense and damage caused by P. aeruginosa infections. Molecular analyses showed that Palestinian fluoroquinolone resistant P. aeruginosa haplotypes are not genetically differentiated; however, more mutations may exist in these strains.