Class 1 integrons and resistance gene cassettes among multidrug resistant Salmonella serovars isolated from slaughter animals and foods of animal origin in Ethiopia

Acta Tropica ◽  
2007 ◽  
Vol 103 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Bayleyegn Molla ◽  
Angelika Miko ◽  
Karin Pries ◽  
Goetz Hildebrandt ◽  
Josef Kleer ◽  
...  
2001 ◽  
Vol 67 (12) ◽  
pp. 5675-5682 ◽  
Author(s):  
Anja S. Schmidt ◽  
Morten S. Bruun ◽  
Inger Dalsgaard ◽  
Jens L. Larsen

ABSTRACT A collection of 313 motile aeromonads isolated at Danish rainbow trout farms was analyzed to identify some of the genes involved in high levels of antimicrobial resistance found in a previous field trial (A. S. Schmidt, M. S. Bruun, I. Dalsgaard, K. Pedersen, and J. L. Larsen, Appl. Environ. Microbiol. 66:4908–4915, 2000), the predominant resistance phenotype (37%) being a combined oxytetracycline (OTC) and sulphadiazine/trimethoprim resistance. Combined sulphonamide/trimethoprim resistance (135 isolates) appeared closely related to the presence of a class 1 integron (141 strains). Among the isolates containing integrons, four different combinations of integrated resistance gene cassettes occurred, in all cases including a dihydrofolate reductase gene and a downstream aminoglycoside resistance insert (87 isolates) and occasionally an additional chloramphenicol resistance gene cassette (31 isolates). In addition, 23 isolates had “empty” integrons without inserted gene cassettes. As far as OTC resistance was concerned, only 66 (30%) out of 216 resistant aeromonads could be assigned to resistance determinant class A (19 isolates), D (n = 6), or E (n = 39); three isolates contained two tetracycline resistance determinants (AD, AE, and DE). Forty OTC-resistant isolates containing large plasmids were selected as donors in a conjugation assay, 27 of which also contained a class 1 integron. Out of 17 successful R-plasmid transfers to Escherichia coli recipients, the respective integrons were cotransferred along with the tetracycline resistance determinants in 15 matings. Transconjugants were predominantly tetApositive (10 of 17) and contained class 1 integrons with two or more inserted antibiotic resistance genes. While there appeared to be a positive correlation between conjugative R-plasmids andtetA among the OTC-resistant aeromonads, tetEand the unclassified OTC resistance genes as well as class 1 integrons were equally distributed among isolates with and without plasmids. These findings indicate the implication of other mechanisms of gene transfer besides plasmid transfer in the dissemination of antibiotic resistance among environmental motile aeromonads.


2005 ◽  
Vol 49 (3) ◽  
pp. 1194-1197 ◽  
Author(s):  
Laura Villa ◽  
Alessandra Carattoli

ABSTRACT A virulence plasmid was identified in a multidrug-resistant Salmonella enterica serotype Typhimurium strain carrying the spvC, rck, and pefA virulence genes and two class 1 integrons linked to the Tn21 and Tn1696 transposons. A novel trimethoprim resistance gene, designated dfrA23, was also identified within the integron region. The association of multidrug resistance and virulence determinants represents an interesting example of virulence plasmid evolution.


2000 ◽  
Vol 44 (5) ◽  
pp. 1315-1321 ◽  
Author(s):  
Anders Dalsgaard ◽  
Anita Forslund ◽  
Oralak Serichantalergs ◽  
Dorthe Sandvang

ABSTRACT In this study, 176 clinical and environmental Vibrio cholerae strains of different O serotypes isolated in Thailand from 1982 to 1995 were selected and studied for the presence of class 1 integrons, a new group of genetic elements which carry antibiotic resistance genes. Using PCR and DNA sequencing, we found that 44 isolates contained class 1 integrons harboring the aadB,aadA2, blaP1, dfrA1, anddfrA15 gene cassettes, which encode resistance to gentamicin, kanamycin, and tobramycin; streptomycin and spectinomycin; β-lactams; and trimethoprim, respectively. Each cassette array contained only a single antibiotic resistance gene. Although resistance genes in class 1 integrons were found in strains from the same epidemic, as well as in unrelated non-O1, non-O139 strains isolated from children with diarrhea, they were found to encode only some of the antibiotic resistance expressed by the strains. Serotype O139 strains did not contain class 1 integrons. However, the appearance and disappearance of the O139 serotype in the coastal city Samutsakorn in 1992 and 1993 were associated with the emergence of a distinct V. cholerae O1 strain which contained the aadA2resistance gene cassette. A 150-kb self-transmissible plasmid found in three O1 strains isolated in 1982 contained the aadB gene cassette. Surprisingly, several strains harbored two integrons containing different cassettes. Thus, class 1 integrons containing various resistance gene cassettes are distributed among differentV. cholerae O serotypes of mainly clinical origin in Thailand.


2005 ◽  
Vol 68 (12) ◽  
pp. 2693-2697 ◽  
Author(s):  
L. D. CAMPBELL ◽  
H. M. SCOTT ◽  
K. M. BISCHOFF ◽  
R. C. ANDERSON ◽  
R. B. HARVEY

The prevalence of antimicrobial resistance genotypic characteristics (class 1 integrons and antimicrobial resistance gene cassettes) among commensal Escherichia coli isolated from humans and swine in a semiclosed, integrated farrow-to-fork population was evaluated in a cross-sectional study. The objective of this study was to establish baseline antimicrobial resistance patterns of enteric bacteria from animals and humans within the study population; specifically, genotypic traits both unique and common to commensal E. coli derived from the different sources were evaluated. There were significant differences between host species; swine isolates were more likely to harbor integrons (odds ratio = 2.33, P = 0.0487). No significant differences were found for facility location, facility type, human housing cohort, or time of day (P > 0.05). There were significant differences (P = 0.006) among swine production groups (fecal samples from boars, dry sows, finishers, growers, intake boars, lactating sows, the lagoon, nursery piglets, influent, and piglets); the grower group was less likely than the nursery group to harbor a class 1 integron (nursery as referent: odds ratio = 0.22, P = 0.04). Among all isolates with an integron present, human isolates were more likely to harbor an antimicrobial resistance gene cassette (odds ratio = 6.36, P = 0.003). When isolates that possessed gene cassettes coding for resistance to specific antimicrobials were compared, no significant differences between host species (P > 0.05) were observed.


2020 ◽  
Vol 20 (2) ◽  
pp. 160-166
Author(s):  
Seyedeh Hanieh Eshaghi Zadeh ◽  
Hossein Fahimi ◽  
Fatemeh Fardsanei ◽  
Mohammad Mehdi Soltan Dallal

Background: Salmonellosis is a major food-borne disease worldwide. The increasing prevalence of antimicrobial resistance among food-borne pathogens such as Salmonella spp. is concerning. Objective: The main objective of this study is to identify class 1 integron genes and to determine antibiotic resistance patterns among Salmonella isolates from children with diarrhea. Methods: A total of 30 Salmonella isolates were recovered from children with diarrhea. The isolates were characterized for antimicrobial susceptibility and screened for the presence of class 1 integron genes (i.e. intI1, sulI1, and qacEΔ1). Results: The most prevalent serotype was Enteritidis 36.7%, followed by Paratyphi C (30%), and Typhimurium (16.7%). The highest rates of antibiotic resistance were obtained for nalidixic acid (53.3%), followed by streptomycin (40%), and tetracycline (36.7%). Regarding class 1 integrons, 36.7%, 26.7%, and 33.3% of the isolates carried intI1, SulI, and qacEΔ1, respectively, most of which (81.8%) were multidrug-resistant (MDR). Statistical analysis revealed that the presence of class 1 integron was significantly associated with resistance to streptomycin and tetracycline (p = 0.042). However, there was no association between class 1 integron and other antibiotics used in this study (p > 0.05). Conclusion: The high frequency of integron class 1 gene in MDR Salmonella strains indicates that these mobile genetic elements are versatile among different Salmonella serotypes, and associated with reduced susceptibility to many antimicrobials.


2003 ◽  
Vol 47 (3) ◽  
pp. 249-253 ◽  
Author(s):  
J.C. Park ◽  
J.C. Lee ◽  
J.Y. Oh ◽  
Y.W. Jeong ◽  
J.W. Cho ◽  
...  

Coliform bacteria isolated from the aquatic environment were investigated for antibiotic susceptibility and detailed structures of class 1 integrons. A high proportion of isolates were found to be resistant to sulfamethoxazole, aminoglycosides, and β-lactams. The 750 (53.6%) isolates were resistant to one or more of the antibiotics tested out of 1,400 coliform bacteria. Based on the MIC of antibiotics and antibiogram, 150 isolates were selected and further studied for class 1 integrons. The intI1 gene was found in 36 (24.0%) of the 150 isolates. Twelve isolates carried the gene cassettes responsible for antibiotic resistance, while no gene cassettes were found in 24 isolates. Seven different genes, dfrA5, dfrA7, dfrA12, dfrA17, aaA2, aaA5, and aad(3’), were detected in gene cassettes. The dfrA and aad genes located on class 1 integrons were responsible for resistance to trimethoprim and aminoglycosides. The remaining 24 coliform bacteria had the incomplete or non-functional class 1 integrons. These results indicated that antibiotic selective pressures may play an important role to maintain gene cassettes of class 1 integrons and in the absence of sustained antibiotic pressures, such as the aquatic environment, coliform bacteria may carry empty or non-functional class 1 integrons.


2011 ◽  
Vol 77 (20) ◽  
pp. 7147-7150 ◽  
Author(s):  
Kristina Kadlec ◽  
Ellen von Czapiewski ◽  
Heike Kaspar ◽  
Jürgen Wallmann ◽  
Geovana Brenner Michael ◽  
...  

ABSTRACTSulfonamide-trimethoprim-resistantAeromonas salmonicidaand motileAeromonasspp. from diseased fish of the GERM-Vet study carried thesul1gene together with mostly cassette-borne trimethoprim resistance genes, including the novel genedfrA28. The sevendfrAanddfrBgenes identified were located mostly in class 1 integrons which commonly harbored other gene cassettes.


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