title: Molecular Evaluation of High Fluoroquinolone Resistant Genes in Endemic Cases of Shigellosis, Northeast Part of Karnataka, India.
abstract: Shigellosis is an acute infection of the intestine caused by bacteria in the genus Shigella and also an important cause of diarrhea in developing countries. This study was carried out to find the extent and nature of the emerging resistance in north part of Karnataka, India, and surrounding region with huge population, and also focused on the molecular mechanism of development of resistance against different generations of fluoroquinolones and explored the diversity of restriction endonucleases; we also tried to establish the significance of reduced minimal inhibitory concentrations (MIC) values.
  
  
  
  A total of 32 multidrug-resistant Shigella species (isolated from infants' stools) were subjected to MICs of fluoroquinolone-resistant isolates done by both broth dilution and E-test method. The genes implicated in resistance to fluoroquinolone generations ciprofloxacin, ofloxacin, and gatifloxacin (gyrA, gyrB, parC, and parE) were amplified using polymerase chain reaction (PCR) method and restriction digestion analysis of PCR product were performed using PvuI and HaeII enzymes.
  
  
  
  Fluoroquinolone-resistant Shigella species (n = 32) comprising S dysenteriae, S flexneri, and S sonnei were selected for MIC; 90.6% (29/32), 93.75% (30/32), and 93.75% (30/32) of isolates were ciprofloxacin, ofloxacin, and gatifloxacin resistant and showed the MIC range from 4-128 μg/mL. The PCR amplification results were positive for all species and asserted the presence of gyrA, gyrB, parC, and pare and sizes of the amplified products. The restriction banding patterns of amplified resistant genes were employed to detect differences among the Shigella species.
  
  
  
  The present study found that the genetic basis and its characterization of fluoroquinolone resistance in Shigella isolates was considered for the common resistant genes, namely, gyrA, gyrB, parC, and pare, and had mutations at position 83 of gyrA and at position 80 of parC of the quinolone-resistant determining regions and associated molecular mechanism. Our study beneficial in identification of the causative agents of the infections, careful control and cautions use of antibiotics must be promoted, particularly to monitor the emergence of isolates that are fully resistant to fluoroquinolones.
authors.affiliation: Medical Biotechnology and Phage Therapy Laboratory, Department of Post Graduate Studies and Research in Biotechnology, Gulbarga University, Gulbarga, Karnataka, India.
authors.forename: Prabhurajeshwar
authors.initials: P
authors.lastname: C
authors.affiliation: Medical Biotechnology and Phage Therapy Laboratory, Department of Post Graduate Studies and Research in Biotechnology, Gulbarga University, Gulbarga, Karnataka, India.
authors.forename: Pramod
authors.initials: P
authors.lastname: Desai
authors.affiliation: Medical Biotechnology and Phage Therapy Laboratory, Department of Post Graduate Studies and Research in Biotechnology, Gulbarga University, Gulbarga, Karnataka, India. Electronic address: ckelmani64@gmail.com.
authors.forename: Kelmani Chandrakanth
authors.initials: KC
authors.lastname: R
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics; D004405:Dysentery, Bacillary / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D019353:Endemic Diseases; D005243:Feces / Q000382:microbiology; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D007194:India / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D012760:Shigella / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D024841:Fluoroquinolones
keywords: PCR amplification; QRDRs; Shigella species; and parE; fluoroquinolone genes; genomic DNA; gyrA; gyrB; minimal inhibitory concentration (MICs); parC; restriction digestion and shigellosis