Evaluation of resistance to ciprofloxacin and identification of mutations in topoisomerase genes in Escherichia coli and Klebsiella pneumonia isolated from pediatric urinary tract infections

INTRODUCTION: Urinary tract infection (UTI) is one of the common infectious diseases of children. Due to the limited use of fluoroquinolones in children, they still have no resistance problems as the same as the adult population. However, recent reports suggested an increase in resistance to fluoroquinolones among bacteria caused UTI in children. Therefore, the aim of this study is to evaluate the prevalence of Escherichia coli and Klebsiella pneumoniae isolates resistant to ciprofloxacin and to detect mutations in their gyrA and parC genes.
METHODS: The present study was conducted on 78 bacterial strains isolated from the children with UTI during 2016-2017 at Imam Reza Hospital in Kermanshah, Iran. The bacteria were identified based on microbiological methods and antibiotic susceptibility test using disc diffusion and broth microdilution methods. Then, PCR and sequencing were performed to investigate mutations in gyrA and parC genes.
RESULTS: In general, 15.3 of isolates of E. coli and K. pneumonia were resistant to ciprofloxacin. Sequence analysis confirmed mutations in gyrA and parC genes in all of the isolates resistant to ciprofloxacin. The results showed changes in amino acids (ser83leu, ser83phe and Asp87Asn) in codons 83 and 87 in the QRDR region of the gyrA gene, three substitutions in both the 80 and 84 positions in the parC, ser80Ile, Glu84val and Glu84lys genes.
DISCUSSION AND CONCLUSION: The results of this study revealed resistance to ciprofloxacin in the pediatric population. Given that the use of ciprofloxacin in children is limited, this resistance cannot be due to the antibiotic selective pressure. On the other hand, the mutations in the gyrA and parC genes in children was similar to adults which indicate that these resistant isolates can be transmitted from adults to children.