Carriage of Class 1 integrons and molecular characterization of intI1 gene in multidrug-resistant Salmonella spp. isolates from broilers.

Renu Gupta,N K Mahajan,Sneh Lata Chauhan,V G Joshi,Naresh Jindal,Sunil Kumar

doi:10.14202/vetworld.2019.609-613

Renu Gupta, N K Mahajan + Show 4 more

Open Access

https://doi.org/10.14202/vetworld.2019.609-613

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Abstract

Aim:The present study was conducted with the following aims: (i) To screen the Salmonella spp. isolates recovered from suspected cases of fowl typhoid for carriage of Class 1 integrons and analyze their association with antimicrobial resistance and (ii) to carry out molecular characterization and phylogenetic analysis of Class 1 integron-integrase (intI1) gene.Materials and Methods:A total of 43 Salmonella isolates were subjected to polymerase chain reaction (PCR) assay to determine the presence of Class1 intI1. Differences between different serotypes in relation to their carriage of integrons and the differences between strains containing or not containing an integron and being resistant to different antimicrobials were analyzed by Fisher exact test using STATA™ (StataCorp, College Station, TX). Phylogenetic analysis was carried out using MEGA6 software.Results:Out of 43 isolates, 40 (93.02%) were found positive for Class 1 integrons. 35/40 (87.5%) intI1-positive isolates were multidrug resistance (MDR) (resistant to ≥4 antibiotics), which support the hypothesis of an association between the presence of Class 1 integrons and emerging MDR in Salmonella. There was no significant difference among isolates resistant to different antimicrobials in Class 1 integron carrying isolates and the Class 1 integron negative isolates (p<0.05). Further, there was no significant difference among different serotypes in respect of their carriage of Class 1 integrons.Conclusion:It can be concluded that the high prevalence of Class 1 integrons indicates a high potential of Salmonella isolates for horizontal transmission of antimicrobial genes, especially among Gram-negative organisms.

Highlights

Integron system is one of the important dynamic mechanisms in the evolution of multidrug resistance (MDR) which helps bacteria to acquire resistance genes in novel combinations enabling them to resist several antimicrobial agents and is frequently associated with the development of MDR in Gram-negative bacteria [1]
Out of 43 isolates, 40 (93.02%) were found positive for Class 1 integrons. 35/40 (87.5%) intI1-positive isolates were multidrug resistance (MDR), which support the hypothesis of an association between the presence of Class 1 integrons and emerging MDR in Salmonella
It can be concluded that the high prevalence of Class 1 integrons indicates a high potential of Salmonella isolates for horizontal transmission of antimicrobial genes, especially among Gram-negative organisms

Summary

Introduction

Integron system is one of the important dynamic mechanisms in the evolution of multidrug resistance (MDR) which helps bacteria to acquire resistance genes in novel combinations enabling them to resist several antimicrobial agents and is frequently associated with the development of MDR in Gram-negative bacteria [1]. Class 1 integrons, the most common type, mostly found as part of the Tn21 or Tn402 transposon family, have been detected in bacteria in many regions and have been identified as a primary source of antimicrobial resistance (AMR) genes and suspected to serve as reservoirs capable of exchanging resistance genes in a variety of Gram-negative bacteria [3,4]. They contain a 5′ conserved segment (5′CS) and a 3′ conserved segment (3′CS) [5]

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