Identification and characterization of class 1 integron-mediated antibiotics resistance among Shiga toxin-producing Escherichia coli isolates

ABSTRACT Further characterization of the genetic environment of the gene encoding the Escherichia coli extended-spectrum β-lactamase, bla VEB-1, revealed the presence of a plasmid-located class 1 integron, In53, which carried eight functional resistance gene cassettes in addition tobla VEB-1. While the aadB and the arr-2 gene cassettes were identical to those previously described, the remaining cassettes were novel: (i) a novel nonenzymatic chloramphenicol resistance gene of the cmlAfamily, (ii) a qac allele encoding a member of the small multidrug resistance family of proteins, (iii) a cassette,aacA1b/orfG, which encodes a novel 6′-N-acetyltransferase, and (iv) a fused gene cassette,oxa10/aadA1, which is made of two cassettes previously described as single cassettes. In addition, oxa10 andaadA1 genes were expressed from their own promoter sequence present upstream of the oxa10 cassette.arr-2 coded for a protein that shared 54% amino acid identity with the rifampin ADP-ribosylating transferase encoded by thearr-1 gene from Mycobacterium smegmatisDSM43756. While in M. smegmatis, the main inactivated compound was 23-ribosyl-rifampin, the inactivated antibiotic recovered from E. coli culture was 23-O-ADP-ribosyl-rifampin. The integrase gene of In53 was interrupted by an IS26 insertion sequence, which was also present in the 3′ conserved segment. Thus, In53 is a truncated integron located on a composite transposon, named Tn2000, bounded by two IS26 elements in opposite orientations. Target site duplication at both ends of the transposon indicated that the integron likely was inserted into the plasmid through a transpositional process. This is the first description of an integron located on a composite transposon.

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Identification and Characterization of Class 1 Integron Resistance Gene Cassettes among Salmonella Strains Isolated from Imported Seafood

Applied and Environmental Microbiology ◽

10.1128/aem.02054-08 ◽

2008 ◽

Vol 75 (4) ◽

pp. 1192-1196 ◽

Cited By ~ 27

Author(s):

Ashraf A. Khan ◽

Elizabeth Ponce ◽

M. S. Nawaz ◽

Chorng-Ming Cheng ◽

Junaid A. Khan ◽

...

Keyword(s):

Salmonella Enterica ◽

Southern Hybridization ◽

Multidrug Resistant ◽

The Philippines ◽

Streptomycin Resistance ◽

Class 1 Integron ◽

Class 1 ◽

Identification And Characterization ◽

Multiple Antibiotics

ABSTRACT A total of 210 Salmonella isolates, representing 64 different serovars, were isolated from imported seafood samples, and 55/210 isolates were found to be resistant to at least one antibiotic. Class 1 integrons from three multidrug-resistant Salmonella enterica strains (Salmonella enterica serovars Newport [strain 62], Typhimurium var. Copenhagen [strain 629], and Lansing [strain 803], originating from Hong Kong, the Philippines, and Taiwan, respectively) were characterized. Southern hybridization of plasmids isolated from these strains, using a class 1 integron probe, showed that trimethoprim-sulfamethoxazole and streptomycin resistance genes were located on a megaplasmid in strain 629. Our study indicates that imported seafood could be a reservoir for Salmonella isolates resistant to multiple antibiotics.

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Identification and Characterization of a New Variant of Shiga Toxin 1 in Escherichia coli ONT:H19 of Bovine Origin

Journal of Clinical Microbiology ◽

10.1128/jcm.41.5.2106-2112.2003 ◽

2003 ◽

Vol 41 (5) ◽

pp. 2106-2112 ◽

Cited By ~ 60

Author(s):

C. Burk ◽

R. Dietrich ◽

G. Acar ◽

M. Moravek ◽

M. Bulte ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

New Variant ◽

Identification And Characterization

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Identification and characterization of two novel ISCR1-associated genes dfrA42 and dfrA43 encoding trimethoprim resistant dihydrofolate reductases

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02010-20 ◽

2021 ◽

Author(s):

Ling Li ◽

Mengge Zhang ◽

Wenjia Wang ◽

Ruirui Xia ◽

Yanan Ma ◽

...

Keyword(s):

Escherichia Coli ◽

Complex Class ◽

Class 1 Integrons ◽

Class 1 ◽

Dihydrofolate Reductases ◽

High Level ◽

Identification And Characterization

Two novel ISCR1-associated dfr genes, dfrA42 and dfrA43, were identified from trimethoprim (TMP)-resistant Proteus strains and were shown to confer high level TMP resistance (MIC ≥ 1024 mg/L) when cloned into Escherichia coli. These genes were hosted by complex class 1 integrons suggesting their potentials for dissemination. Analysis of enzymatic parameters and TMP affinity were performed, suggesting that the mechanism of TMP resistance for these novel DHFRs is the reduction of binding with TMP.

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Identification and characterization of class 1 integrons among multidrug-resistant uropathogenic Escherichia coli strains in Mexico

Microbial Pathogenesis ◽

10.1016/j.micpath.2021.105348 ◽

2022 ◽

Vol 162 ◽

pp. 105348

Author(s):

Edgar González-Villalobos ◽

Rosa María Ribas-Aparicio ◽

Laura Belmont-Monroy ◽

Gerardo Aparicio-Ozores ◽

H. Ángel Manjarrez-Hernández ◽

...

Keyword(s):

Escherichia Coli ◽

Multidrug Resistant ◽

Uropathogenic Escherichia Coli ◽

Class 1 Integrons ◽

Class 1 ◽

Identification And Characterization

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Identification and Molecular Characterization of Class 1 Integrons in Multiresistant Escherichia coli Isolates from Poultry Litter

Applied and Environmental Microbiology ◽

10.1128/aem.00660-12 ◽

2012 ◽

Vol 78 (15) ◽

pp. 5444-5447 ◽

Cited By ~ 7

Author(s):

Elizabeth Ponce-Rivas ◽

María-Enriqueta Muñoz-Márquez ◽

Ashraf A. Khan

Keyword(s):

Escherichia Coli ◽

Poultry Litter ◽

Class 1 Integron ◽

Content Type ◽

Gene Cassettes ◽

E Coli ◽

Class 1 ◽

Chicken Litter ◽

Diverse Origin

ABSTRACTThis study describes the prevalence of arrays of class 1 integron cassettes and Qnr determinants (A, B, and S) in 19 fluoroquinolone-resistantEscherichia coliisolates from chicken litter.qnrSandqnrAwere the predominant genes in these fluoroquinolone-resistant isolates, and an uncommon array ofaacA4-catB3-dfrA1gene cassettes from a class1 integron was found. Additionally,aadA1anddfrA1gene cassettes, encoding resistance to streptomycin and trimethoprim, constituted the most common genes identified and was located on megaplasmids as well on the chromosome. Antibiotic resistance, pulsed-field gel electrophoresis (PFGE), and plasmid data suggest a genetically diverse origin of poultryE. coliisolates.

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Identification and Characterization of Shiga Toxin Type 2 Variants in Escherichia coli Isolates from Animals, Food, and Humans

Applied and Environmental Microbiology ◽

10.1128/aem.00503-08 ◽

2008 ◽

Vol 74 (18) ◽

pp. 5645-5652 ◽

Cited By ~ 31

Author(s):

Jie Zheng ◽

Shenghui Cui ◽

Louise D. Teel ◽

Shaohua Zhao ◽

Ruby Singh ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Gene Encoding ◽

Intestinal Mucus ◽

One Step ◽

A Subunit ◽

Pcr Method ◽

Identification And Characterization

ABSTRACT There is considerable heterogeneity among the Shiga toxin type 2 (Stx2) toxins elaborated by Shiga toxin-producing Escherichia coli (STEC). One such Stx2 variant, the Stx2d mucus-activatable toxin (Stx2dact), is rendered more toxic by the action of elastase present in intestinal mucus, which cleaves the last two amino acids of the A2 portion of the toxin A subunit. We screened 153 STEC isolates from food, animals, and humans for the gene encoding Stx2dact by using a novel one-step PCR procedure. This method targeted the region of stx 2dact that encodes the elastase recognition site. The presence of stx 2dact was confirmed by DNA sequencing of the complete toxin genes. Seven STEC isolates from cows (four isolates), meat (two isolates), and a human (one isolate) that carried the putative stx 2dact gene were identified; all were eae negative, and none was the O157:H7 serotype. Three of the isolates (CVM9322, CVM9557, and CVM9584) also carried stx 1, two (P1332 and P1334) carried stx 1 and stx 2c, and one (CL-15) carried stx 2c. One isolate, P1130, harbored only stx 2dact. The Vero cell cytotoxicities of supernatants from P1130 and stx 1 deletion mutants of CVM9322, CVM9557, and CVM9584 were increased 13- to 30-fold after treatment with porcine elastase. Thus, Stx2dact-producing strains, as detected by our one-step PCR method, can be isolated not only from humans, as previously documented, but also from food and animals. The latter finding has important public health implications based on a recent report from Europe of a link between disease severity and infection with STEC isolates that produce Stx2dact.

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Identification and Characterization of Integron-Mediated Antibiotic Resistance among Shiga Toxin-Producing Escherichia coli Isolates

Applied and Environmental Microbiology ◽

10.1128/aem.67.4.1558-1564.2001 ◽

2001 ◽

Vol 67 (4) ◽

pp. 1558-1564 ◽

Cited By ~ 147

Author(s):

Shaohua Zhao ◽

David G. White ◽

Beilei Ge ◽

Sherry Ayers ◽

Sharon Friedman ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Shiga Toxin ◽

Antibiotic Resistance Gene ◽

Gene Encoding ◽

Gene Cassettes ◽

E Coli ◽

Class 1 Integrons ◽

Class 1

ABSTRACT A total of 50 isolates of Shiga toxin-producing Escherichia coli (STEC), including 29 O157:H7 and 21 non-O157 STEC strains, were analyzed for antimicrobial susceptibilities and the presence of class 1 integrons. Seventy-eight (n = 39) percent of the isolates exhibited resistance to two or more antimicrobial classes. Multiple resistance to streptomycin, sulfamethoxazole, and tetracycline was most often observed. Class 1 integrons were identified among nine STEC isolates, including serotypes O157:H7, O111:H11, O111:H8, O111:NM, O103:H2, O45:H2, O26:H11, and O5:NM. The majority of the amplified integron fragments were 1 kb in size with the exception of one E. coli O111:H8 isolate which possessed a 2-kb amplicon. DNA sequence analysis revealed that the integrons identified within the O111:H11, O111:NM, O45:H2, and O26:H11 isolates contained the aadA gene encoding resistance to streptomycin and spectinomycin. Integrons identified among the O157:H7 and O103:H2 isolates also possessed a similaraadA gene. However, DNA sequencing revealed only 86 and 88% homology, respectively. The 2-kb integron of the E. coli O111:H8 isolate contained three genes, dfrXII,aadA2, and a gene of unknown function, orfF, which were 86, 100, and 100% homologous, respectively, to previously reported gene cassettes identified in integrons found inCitrobacter freundii and Klebsiella pneumoniae. Furthermore, integrons identified among the O157:H7 and O111:NM strains were transferable via conjugation to another strain of E. coli O157:H7 and to several strains of Hafnia alvei. To our knowledge, this is the first report of integrons and antibiotic resistance gene cassettes in STEC, in particular E. coliO157:H7.

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