Dataset Information

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

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.

SUBMITTER: Gupta R

PROVIDER: S-EPMC6515832 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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

Gupta Renu R Chauhan Sneh Lata SL Kumar Sunil S Jindal Naresh N Mahajan N K NK Joshi V G VG

Veterinary world 20190425 4

<h4>Aim</h4>The present study was conducted with the following aims: (i) To screen the <i>Salmonella</i> 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 (<i>intI1</i>) gene.<h4>Materials and methods</h4>A total of 43 <i>Salmonella</i> isolates were subjected to polymerase chain reaction ...[more]

PMID: 31190719

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Project description:Salmonella enterica subsp. enterica serovar Infantis is the most prevalent serovar found in broilers and broiler meat and is among the top five serovars responsible for human infections in Europe. In 2008, a multidrug-resistant S. Infantis isolate emerged in Israel with a mosaic megaplasmid named pESI, associated with increased virulence, biofilm formation, and multidrug resistance. Since then, S. Infantis clones with pESI-like plasmids have been reported worldwide, replacing pESI-free clones. Here, we typed 161 S. Infantis isolates of poultry (n = 133) and human clinical (n = 28) origin using whole-genome sequencing. The isolates were collected between 2007 and 2021. In addition, we performed PacBio/Illumina sequencing for two representative pESI-like plasmids and compared them with publicly available sequences. All isolates belonged to sequence type 32 (ST32), except for one isolate that represented a novel single-locus variant of ST32. Core genome MLST (cgMLST) analysis revealed 14 clusters of genetically closely related isolates, of which four suggested broiler-to-human transmission of S. Infantis. pESI-like plasmids were present in 148/161 (91.9%) isolates; all were highly similar to the publicly available pESI-like sequences but lacked extended-spectrum beta-lactamase (ESBL) genes. PacBio/Illumina hybrid assembly allowed the reconstruction of two novel complete pESI variants. The present study revealed that the multidrug-resistant, pESI-positive S. Infantis clone became the predominant S. Infantis clone in Slovenian broilers and humans during the last decade. Continued surveillance of resistant S. Infantis clones along the food chain is needed to guide public health efforts. IMPORTANCE Salmonella Infantis clones with pESI-like plasmids harboring several virulence and resistance genes have been reported worldwide. In the present study, we compared the population structure of 161 Salmonella Infantis isolates obtained from humans and broilers in Slovenia from 2007 to 2021. Whole-genome sequencing showed that most human isolates clustered apart from broiler isolates, suggesting an alternative source of infection. Most isolates were multidrug resistant due to the presence of pESI-like plasmids, of which two variants (pS89 and pS19) were fully reconstructed using long-read sequencing. Both exhibited high similarity with the original Israeli pESI plasmid and German p2747 plasmid. The prototype plasmid pS89 harbored the typical pESI-associated resistance genes aadA1, qacEΔ1, sul1, and tet(A), which were absent in the truncated plasmid pS19.

Project description:Salmonella enterica serovar Indiana (S. Indiana) has aroused widespread concern as an important zoonotic pathogen. The molecular mechanism of multidrug resistance (MDR) in S. Indiana is not known and should be assessed. We aim to investigate the molecular mechanism of MDR and the importance of large plasmids carried class 1 integrons in the MDR of foodborne S. Indiana. Class 1 integrons in 48 S. Indiana isolates and 200 isolates of 7 other Salmonella serotypes were detected by polymerase chain reaction (PCR). To analyze the antimicrobial resistance genes (ARGs) of two S. Indiana isolates, designated S. Indiana 15 and S. Indiana 222, next-generation sequencing (NGS) was performed, and the resulting sequences were compared with the complete nucleotide sequences of S. Indiana D90 and S. Indiana C629. Comparative functional analysis was conducted between the intI1 (1,014 bp) of S. Indiana 222 and the intI1 (699 bp) of S. Indiana 15. Plasmid conjugation transfer analysis was performed to analyze the horizontal gene transfer of the integrons-related resistance genes with integron-positive and integron-negative Salmonella isolates. 64.58% of S. Indiana isolates carried class 1 integrons, which was significantly higher than that of other Salmonella serotypes (p < 0.001). The NGS results showed that the S. Indiana 15 and S. Indiana 222 isolates carried a large plasmid with a class 1 integron and multiple ARGs, similar to S. Indiana D90 and S. Indiana C629. Two integrases found in S. Indiana isolates belong to class 1 integrases and could integrate resistance genes into specific integration sites of the integrons. The conjugation frequency of intI1 (1,014 bp) was 6.08 × 10-5, which was significantly higher than that of intI1 (699 bp) (p < 0.01). The large plasmids carrying a class 1 integron and the number of ARGs were strongly correlated (p < 0.001). The conjugation frequency of integron-positive S. Indiana recipient isolates was significantly higher than that of integron-negative recipient isolates (p < 0.05). S. Indiana containing large plasmids carrying a class 1 integron more easily captured resistance genes from other bacteria (S. Enteritidis and S. Derby), which could be an important cause of the emerging pandemic of MDR clones. Graphical abstractS. Indiana containing large plasmids carrying a class 1 integron more easily captured resistance genes from other bacteria (S. Enteritidis and S. Derby), which could be an important cause of the emerging pandemic of MDR clones.

Project description:BACKGROUND:The worldwide increase of food-borne infections with antibiotic resistant pathogens constitutes a major public health problem. Therefore, this study aimed to determine the prevalence, antibiogram, virulence genes profiles and integron characteristics of non-typhoidal Salmonella spp. isolated from poultry meat and diarrhoeic patients in Egypt. METHODS:A total of 150 samples comprising (100 poultry meat and 50 diarrhoeic patients' stool) were examined for the presence of Salmonella spp. using culture methods followed by biochemical and serological identification of the isolates. All Salmonella strains were tested for their susceptibility to the antibiotics using disk diffusion method and screened for the presence of virulence genes and class I integrons using PCR. RESULTS:The overall prevalence of Salmonella spp. in poultry meat samples was 10 % compared to 4 % in diarrhoeic patients. All the isolates were serologically identified into Salmonella Typhimurium (seven isolates), S. Derby, S. Kiel, S. Rubislaw (one isolate, each) and untypable strains (two isolates). Antibiotic susceptibility testing showed a higher resistance of the total isolates to erythromycin and tetracycline (100 %, each), followed by amoxicillin-clavulanic acid (91.7 %), trimethoprim-sulfamethoxazole (83.3 %), streptomycin, nalidixic acid, ampicillin-sulbactam (75 %, each), gentamycin, ampicillin (66.7 %, each), chloramphenicol (58.3 %), ciprofloxacin (25 %) and ceftriaxone (16.7 %). Virulence genes profiles revealed the presence of sopB gene in five Salmonella strains isolated from poultry meat (n = 3) and humans (n = 2). Moreover, pefA was only identified in three isolates from poultry meat. On the other hand, S. Kiel and S. Typhimurium (one isolate, each) were harboring hilA and stn genes, respectively. Class 1 integrons were detected in all Salmonella spp. with variable amplicon sizes ranged from 650-3000 bp. Sequencing of these amplicons revealed the presence of gene cassettes harboring aac(3)-Id, aadA2, aadA4, aadA7, sat, dfrA15, lnuF and estX resistance genes. Nucleotide sequence analysis showed point mutations in the aac(3)-Id of S. Derby, aadA2, estX-sat genes of S. Typhimurium. Meanwhile, frame shift mutation was observed in aadA7 genes of S. Typhimurium. CONCLUSIONS:Increasing rate of antimicrobial resistance and class 1 integrons among multidrug resistant Salmonella spp. has prompted calls for the reduction of antimicrobial use in livestock to prevent future emergence of resistance.

Dataset Information

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

Publications

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

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