Emergence of multidrug-resistant Salmonella enterica serovar Typhi associated with a class 1 integron carrying the dfrA7 gene cassette in Nepal

2007 ◽  
Vol 30 (4) ◽  
pp. 330-335 ◽  
Author(s):  
Migma Dorji Tamang ◽  
Jae Young Oh ◽  
Sung Yong Seol ◽  
Hee Young Kang ◽  
Je Chul Lee ◽  
...  
2003 ◽  
Vol 47 (6) ◽  
pp. 2006-2008 ◽  
Author(s):  
Hyunjoo Pai ◽  
Jeong-hum Byeon ◽  
Sunmi Yu ◽  
Bok Kwon Lee ◽  
Shukho Kim

ABSTRACT Six strains of Salmonella enterica serovar Typhi which were resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, streptomycin, tetracycline, and gentamicin were isolated in Korea. This multidrug resistance was transferred by a conjugative plasmid of about 50 kb. The plasmid harbored a class 1 integron, which included six resistance genes, aacA4b, catB8, aadA1, dfrA1, aac(6′)-IIa, and the novel blaP2, in that order. All of the isolates showed the same-size plasmids and the same ribotyping patterns, which suggests a clonal spread of these multidrug-resistant isolates.


2010 ◽  
Vol 76 (11) ◽  
pp. 3657-3667 ◽  
Author(s):  
Janine Beutlich ◽  
Irene Rodr�guez ◽  
Andreas Schroeter ◽  
Annemarie K�sbohrer ◽  
Reiner Helmuth ◽  
...  

ABSTRACT Recently, Salmonella enterica subsp. enterica serovar Saintpaul has increasingly been observed in several countries, including Germany. However, the pathogenic potential and epidemiology of this serovar are not very well known. This study describes biological attributes of S. Saintpaul isolates obtained from turkeys in Germany based on characterization of their pheno- and genotypic properties. Fifty-five S. Saintpaul isolates from German turkeys and turkey-derived food products isolated from 2000 to 2007 were analyzed by using antimicrobial agent, organic solvent, and disinfectant susceptibility tests, isoelectric focusing, detection of resistance determinants, plasmid profiling, pulsed-field gel electrophoresis (PFGE), and hybridization experiments. These isolates were compared to an outgroup consisting of 24 S. Saintpaul isolates obtained from humans and chickens in Germany and from poultry and poultry products (including turkeys) in Netherlands. A common core resistance pattern was detected for 27 German turkey and turkey product isolates. This pattern included resistance (full or intermediate) to ampicillin, amoxicillin-clavulanic acid, gentamicin, kanamycin, nalidixic acid, streptomycin, spectinomycin, and sulfamethoxazole and intermediate resistance or decreased susceptibility to ciprofloxacin (MIC, 2 or 1 μg/ml, respectively) and several third-generation cephalosporins (including ceftiofur and cefoxitin [MIC, 4 to 2 and 16 to 2 μg/ml, respectively]). These isolates had the same core resistance genotype, with bla TEM-1, aadB, aadA2, sul1, a Ser83→Glu83 mutation in the gyrA gene, and a chromosomal class 1 integron carrying the aadB-aadA2 gene cassette. Their XbaI, BlnI, and combined XbaI-BlnI PFGE patterns revealed levels of genetic similarity of 93, 75, and 90%, respectively. This study revealed that a multiresistant S. Saintpaul clonal line is widespread in turkeys and turkey products in Germany and was also detected among German human fecal and Dutch poultry isolates.


2013 ◽  
Vol 7 (12) ◽  
pp. 929-940 ◽  
Author(s):  
Amna Afzal ◽  
Yasra Sarwar ◽  
Aamir Ali ◽  
Abbas Maqbool ◽  
Muhammad Salman ◽  
...  

Introduction: This study aimed to determine the drug susceptibility patterns and genetic elements related to drug resistance in isolates of Salmonella enterica serovar Typhi (S. Typhi) from the Faisalabad region of Pakistan. Methodology: The drug resistance status of 80 isolates were evaluated by determining antimicrobial susceptibility, MICs, drug resistance genes involved, and the presence of integrons. Nalidixic acid resistance and reduced susceptibility to ciprofloxacin were also investigated by mutation screening of the gyrA, gyrB, parC, and parE genes. Results: Forty-seven (58.7%) isolates were multidrug resistant (MDR). Among the different resistance (R) types, the most commonly observed (13/80) was AmChStrTeSxtSmzTmp, which is the most frequent type observed in India and Pakistan. The most common drug resistant genes were blaTEM-1, cat, strA-strB, tetB, sul1, sul2, and dfrA7. Among the detected genes, only dfrA7 was found to be associated in the form of a single gene cassette within the class 1 integrons. Conclusions: MIC determination of currently used drugs revealed fourth-generation gatifloxacin as an effective drug against multidrug-resistant S. Typhi, but its clinical use is controversial. The Ser83→Phe substitution in gyrA was the predominant alteration in nalidixic acid-resistant isolates, exhibiting reduced susceptibility and increased MICs against ciprofloxacin. No mutations in gyrB, parC, or parE were detected in any isolate.


Author(s):  
Jinru Chen ◽  
Joycelyn Quansah

Fresh produce-borne enteric bacterial pathogens with resistance to antibiotics have posed serious challenges to food safety and public health worldwide.  This study examined the antibiotic resistance profile of Salmonella enterica (n=33), previously isolated from exotic and indigenous leafy green vegetable samples (n=328) collected from 50 vegetable farms in 12 farming areas and 37 vegetable sellers in 4 market centers in Accra, Ghana during the period of March 2016 to March 2017, and determined the distribution of integrons among antibiotic-resistant isolates.  The susceptibility of the Salmonella isolates to 12 antibiotics was assayed using the standard disc diffusion assay.  The minimum inhibitory concentrations (MICs) of the five most resisted antibiotics were determined using the twofold macro dilution method.  PCR assay was used to detect the presence of integrons in Salmonella cells, and PCR product with amplified integron gene cassette was purified and sequenced using the Sanger sequencing technology.  The Salmonella isolates used in the study resisted at least one tested antibiotic, and multi-drug resistant (MDR) isolates were 30.3% (10/33).  Most isolates (81.8%) were resistant to sulfisoxazole.  The MICs of tetracycline, cefoxitin, streptomycin, ampicillin, and sulfisoxazole were 16, 32, 64, 64, and > 1,024 µg/ml, respectively.  A total of five different patterns of MDR were observed among the Salmonella isolates, and the common MDR patterns were AAuFox (30.3%) and AAuFoxSSu (18.1%).  One out of the 33 (3.0%) Salmonella isolates tested positive for class 1 integron with a gene cassette of about 800 bp.  Nucleotide sequencing revealed the class 1 integron carried a single gene dfrA7 .  Future studies are needed to confirm whether the consumption of contaminated leafy green vegetables is a route of acquiring antibiotic-resistant Salmonella by consumers in Accra, Ghana.


2004 ◽  
Vol 48 (11) ◽  
pp. 4130-4135 ◽  
Author(s):  
Kyungwon Lee ◽  
Dongeun Yong ◽  
Jong Hwa Yum ◽  
Young Sik Lim ◽  
Hyun Sook Kim ◽  
...  

ABSTRACT A chloramphenicol-resistant strain of Salmonella enterica serovar Typhi was first noted in Korea in 1992, when a resistant isolate was detected in a returned traveler. Continued isolation of multidrug-resistant (MDR) strains thereafter in other settings prompted a retrospective analysis of laboratory records and phenotypic and genotypic analyses of 12 chloramphenicol-resistant isolates. Among these, one isolate was resistant only to chloramphenicol, and the other isolates were also resistant to ampicillin and co-trimoxazole. MDR was transferred by conjugation from 9 of the 11 isolates. PCR showed that all isolates had an incompatible group HI1 plasmid, and oriT was detected in 10 isolates, which included strains with an unsuccessful transfer of resistance. All of the ampicillin-resistant isolates had a β-lactamase band of pI 5.4 and bla TEM alleles. A PCR amplicon from an isolate showed that the sequences were identical to those of bla TEM-1, suggesting that all isolates had a TEM-1 β-lactamase. All isolates had class 1 integrons: 10 isolates had integrons of ca. 1.2 kb with dhfr7 gene cassettes, and 1 isolate had an integron of ca. 2.3 kb with aacA4 and bla OXA-1-like gene cassettes. The pulsed-field gel electrophoresis patterns of 7 of 11 MDR isolates were identical and indistinguishable from those reported for isolates in India and Indonesia. In conclusion, some of the MDR strains in Korea are related to those in other Asian countries. Susceptibility testing became necessary for selection of antimicrobial agents for the optimal treatment of patients with the emergence of MDR Salmonella serovar Typhi in Korea.


2005 ◽  
Vol 49 (2) ◽  
pp. 503-511 ◽  
Author(s):  
Wondwossen A. Gebreyes ◽  
Siddhartha Thakur

ABSTRACT Salmonella serovars are important reservoirs of antimicrobial resistance. Recently, we reported on multidrug-resistant (MDR) Salmonella enterica serovar Typhimurium strains among pigs with resistance to ampicillin, kanamycin, streptomycin, sulfamethoxazole, and tetracycline (resistance [R] type AKSSuT) and resistance to amoxicillin-clavulanic acid, ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (R type AxACSSuT). In the present study, 67 isolates (39 from humans and 28 from pigs) of clinically important Salmonella serovar Muenchen were characterized. Among the porcine isolates, 75% showed resistance to seven antimicrobials: ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, amoxicillin-clavulanic acid, and kanamycin (R type ACSSuTAxK). One isolate from humans showed resistance to 10 of the 12 antimicrobials: ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, amoxicillin-clavulanic acid, kanamycin, gentamicin, cephalothin, and ceftriaxone (R type ACSSuTAxKGCfCro). Pulsed-field gel electrophoresis revealed no clonality between the porcine and the human strains. The porcine and the human MDR strains carried class 1 integrons of 2.0 and 1.0 kb, respectively. Genes specific to the porcine strain included aadA2, aphA1-Iab, and tetA(B). DNA sequencing revealed that the porcine isolates carried bla OXA-30 on a class 1 integron. Genes specific to the human strain included bla TEM, strA, strB, cmlA, tetA(A), and aadA2. No bla CMY-2 gene was detected. Serovar Muenchen strains of porcine and human origin were able to transfer resistance genes to laboratory strain Escherichia coli MG1655 by conjugation. Plasmid restriction with four restriction enzymes, EcoRI, BamHI, HindIII, and PstI, showed that the conjugative plasmids from porcine Salmonella serovar Muenchen and Typhimurium R-type MDR strains isolated from the same farms at the same time were similar on the basis of the sizes and the numbers of bands and Southern hybridization. The plasmid profiles among the Salmonella serovar Muenchen isolates from the two host species were different. This is the first report to show a high frequency of MDR Salmonella serovar Muenchen strains from pigs and a human strain that is similar to the MDR isolates with the AmpC enzyme previously reported among Salmonella serovars Newport and Typhimurium strains. The MDR strains from the two host species independently represent public health concerns, as Salmonella serovar Muenchen is among the top 10 causes of salmonellosis in humans.


2009 ◽  
Vol 53 (6) ◽  
pp. 2640-2642 ◽  
Author(s):  
Nick J. Evershed ◽  
Renee S. Levings ◽  
Neil L. Wilson ◽  
Steven P. Djordjevic ◽  
Ruth M. Hall

ABSTRACT IncA/C plasmids carrying an unusual cassette configuration in a class 1 integron and five further shared resistance genes, aacC4, aphA1, hph, sul2, and tetA(D) were found in Salmonella enterica serovars Senftenberg and Ohio. A deletion formed using a short region of homology in the 5′ conserved segment and the orfF cassette created an array with only part of orfF followed by the aadA2 cassette. The IncA/C plasmids were not recoverable by conjugation, but additional conjugative resistance plasmids were present in some strains.


2010 ◽  
Vol 54 (8) ◽  
pp. 3471-3474 ◽  
Author(s):  
Ruirui Xia ◽  
Xianhu Guo ◽  
Yuzhen Zhang ◽  
Hai Xu

ABSTRACT A qnrVC-like gene, qnrVC4, was found in a novel complex class 1 integron gene cassette array following the ISCR1 element and bla PER-1 in a multidrug-resistant strain of the aquatic bacterium Aeromonas punctata. The deduced QnrVC4 protein sequence shares 45% to 81% amino acid identity with quinolone resistance determinants QnrB6, QnrA1, QnrS1, QnrC, QnrVC1, and QnrVC3. A Ser-83 to Ile amino acid substitution in gyrase A may be mainly responsible for ciprofloxacin resistance in this strain.


2008 ◽  
Vol 75 (4) ◽  
pp. 1192-1196 ◽  
Author(s):  
Ashraf A. Khan ◽  
Elizabeth Ponce ◽  
M. S. Nawaz ◽  
Chorng-Ming Cheng ◽  
Junaid A. Khan ◽  
...  

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.


1999 ◽  
Vol 43 (3) ◽  
pp. 693-696 ◽  
Author(s):  
Vincenzo Falbo ◽  
Alessandra Carattoli ◽  
Fabio Tosini ◽  
Cristina Pezzella ◽  
Anna Maria Dionisi ◽  
...  

ABSTRACT Multidrug-resistant Vibrio cholerae O1 El Tor strains isolated during the 1994 outbreak of cholera in Albania and Italy were characterized for the molecular basis of antibiotic resistance. All strains were found to be resistant to tetracycline, streptomycin, spectinomycin, trimethoprim, sulfathiazole, and the vibriostatic compound O/129 (2,4-diamino-6,7-diisopropylteridine). Resistance genes were self-transferable by a conjugative plasmid of about 60 MDa, with the exception of spectinomycin resistance, which was conferred by theaadA1 gene cassette located in the bacterial chromosome within a class 1 integron. The resistance to trimethoprim and O/129 was conferred by the dfrA1 gene, which was present on the plasmid. Although the dfrA1 gene is known to be borne on an integron cassette, class 1, 2, or 3 intI genes were not detected as part of the plasmid DNA from the strains studied.


Sign in / Sign up

Export Citation Format

Share Document