Molecular Characterization of Antibiotic-Resistant Salmonella Isolates from Retail Meat from Markets in Northern Vietnam

2012 ◽  
Vol 75 (9) ◽  
pp. 1709-1714 ◽  
Author(s):  
TRUONG HA THAI ◽  
RYOJI YAMAGUCHI

A total of 118 Salmonella isolates were detected from 283 retail meat samples (135 pork and 148 chicken meat) purchased at retail markets in Northern Vietnam. Thirteen serovars, including Infantis, Anatum, Rissen, Reading, Emek, Typhimurium, Blockley, London, Newport, Derby, Weltevreden, Albany, and Hadar, were determined. Resistance to tetracycline (54.2%), sulfonamides (52.5%), streptomycin (41.5%), trimethoprim (36.4%), chloramphenicol (35.6%), and ampicillin (33.1%) was commonly seen in the Salmonella isolates. Fourteen [blaTEM, blaOXA-1, blaPSE-1, aadA1, sul1, tetA, tetB, tetG, cmlA1, floR, dfrA1, dfrA12, aac(3)-IV, and aphA1-1AB] of 17 resistance genes were detected from the isolates demonstrating resistance. Genes for plasmid-mediated quinolone resistance, such as qnrA, qnrB, qnrS, qepA, and acc(6′)-1b-cr, were not detected in 23 quinolone-resistant isolates. The substitution TCC to TTC at codon 83 of gyrA was found in the 18 quinolone-resistant isolates. The data revealed that resistant Salmonella strains were widely distributed in Northern Vietnam via the food chain and that they might contain multiple genes specifying identical resistance phenotypes. Thus, further studies are necessary to clarify the mechanisms of antibiotic resistance in Salmonella strains and their spread in the livestock market.

2013 ◽  
Vol 295-298 ◽  
pp. 630-634 ◽  
Author(s):  
Ni Ni Han ◽  
Song He Zhang ◽  
Pei Fang Wang ◽  
Chao Wang

The aims of this study are to evaluate multiple antibiotic resistant Escherichia coli isolated from surface water and to investigate the presence and distribution antibiotic resistance genes (ARGs) in sediments of Taihu Lake. The results show that the presentence of four ARGs concentrations in the sediments of the lake was in sequence: strB>qnrB>strA>qnrS, as determined by realtime-PCR technique. The southwest and east areas of Taihu Lake were polluted seriously than other areas from all kinds of antibiotics. The screening Escherichia coli had a higher resistance to streptomycin, tetracycline and ampicillin than other four antibiotics, and had a lowest resistance to levofloxacin.


2021 ◽  
Author(s):  
Bahare Moghimi ◽  
Maryam Ghobadi Dana ◽  
Reza Shapouri

Abstract Purpose: Given the increasing use of antibiotics on humans and livestock for treatment or as a growth stimulant, antibiotic resistance has become a general concern. The food chain and specially fermented foods could be a source of antibiotic-resistant bacteria and resistance genes. Lactic Acid Bacteria (LAB) and Lactobacilli are considered safe to use as starter culture or probiotic strains. Recently, however, antibiotic-resistant genes isolated from LABs showed the necessity of setting international regulations to reduce the risk of antibiotic resistance genes transmission via the food chain. The current study aimed to investigate the antibiotic resistance of Lactobacilli isolated from traditional yogurt samples from Zanjan province in Iran.Methods: Lactobacilli characterization and identification were carried out through biochemical and molecular methods. The disk diffusion method was applied to determine phenotype resistance using 13 antibiotic disks resistance genes presence were investigated in the isolates to determine transferability risk, respectively.Results: Based on biochemical and molecular methods, 24 isolates have been identified as Lactobacilli with multiple antibiotic-resistant phenotypes. Vancomycin resistance was a typical phenotype and genotype among isolates. On investigated Lactobacilli chromosome, Tetracycline resistance genes Chloramphenicol (cat), beta-lactam, aminoglycosides (aph (3’)-III), and aadA resistance genes have been detected. While the examined resistance genes have not been detected on the plasmids, they were all on the bacterial chromosome.Conclusion: The results showed that the investigated isolates did not carry the resistance genes on their plasmids. It, therefore, would be a good point since they probably do not transfer resistance genes to other bacteria, and they would be proper candidates to do more investigation for introducing new safe starter culture or probiotic strain to food industries.


2012 ◽  
Vol 57 (No. 4) ◽  
pp. 193-197 ◽  
Author(s):  
H. Momtaz ◽  
E. Rahimi ◽  
S. Moshkelani

This study was carried out to detect the distribution of antibiotic-resistant genes in Escherichia coli isolates from slaughtered commercial chickens in Iran by PCR. The investigated genes included aadA1, tet(A), tet(B), dfrA1, qnrA, aac(3)-IV, sul1, bla<sub>SHV</sub>, bla<sub>CMY</sub>, ere(A), catA1 and cmlA. According to biochemical experiments, 57 isolates from 360 chicken meat samples were recognized as E. coli. The distribution of antibiotic-resistance genes in the E. coli isolates included tet(A) and tet(B) (52.63%), dfrA1, qnrA, catA1 and cmlA (36.84%) and sul1 and ere(A) (47.36%), respectively. Nine strains (15.78%) were resistant to a single antimicrobial agent and 11 strains (19.29%) showed resistance to two antimicrobial agents. Multi-resistance which was defined as resistance to three or more tested agents was found in 64.91% of E. coli strains. The results indicate that all isolates harbour one or more of antibiotic resistance genes and that the PCR technique is a fast, practical and appropriate method for determining the presence of antibiotic-resistance genes. &nbsp;


2006 ◽  
Vol 72 (6) ◽  
pp. 4028-4035 ◽  
Author(s):  
Lilia Macovei ◽  
Ludek Zurek

ABSTRACT In this project, enterococci from the digestive tracts of 260 houseflies (Musca domestica L.) collected from five restaurants were characterized. Houseflies frequently (97% of the flies were positive) carried enterococci (mean, 3.1 � 103 CFU/fly). Using multiplex PCR, 205 of 355 randomly selected enterococcal isolates were identified and characterized. The majority of these isolates were Enterococcus faecalis (88.2%); in addition, 6.8% were E. faecium, and 4.9% were E. casseliflavus. E. faecalis isolates were phenotypically resistant to tetracycline (66.3%), erythromycin (23.8%), streptomycin (11.6%), ciprofloxacin (9.9%), and kanamycin (8.3%). Tetracycline resistance in E. faecalis was encoded by tet(M) (65.8%), tet(O) (1.7%), and tet(W) (0.8%). The majority (78.3%) of the erythromycin-resistant E. faecalis isolates carried erm(B). The conjugative transposon Tn916 and members of the Tn916/Tn1545 family were detected in 30.2% and 34.6% of the identified isolates, respectively. E. faecalis carried virulence genes, including a gelatinase gene (gelE; 70.7%), an aggregation substance gene (asa1; 33.2%), an enterococcus surface protein gene (esp; 8.8%), and a cytolysin gene (cylA; 8.8%). Phenotypic assays showed that 91.4% of the isolates with the gelE gene were gelatinolytic and that 46.7% of the isolates with the asa1 gene aggregated. All isolates with the cylA gene were hemolytic on human blood. This study showed that houseflies in food-handling and -serving facilities carry antibiotic-resistant and potentially virulent enterococci that have the capacity for horizontal transfer of antibiotic resistance genes to other bacteria.


Author(s):  
Juan He ◽  
Cui Li ◽  
Pengfei Cui ◽  
Hongning Wang

Abstract Background: This study was aimed to investigate the prevalence and structure of Tn7-like in Enterobacteriaceae from livestock and poultry as well as their possible role as reservoir of antibiotic resistance genes (ARGs).Methods: Polymerase chain reaction (PCR) and DNA sequencing analyses were used for the characterization of Tn7-like, associated integrons and ARGs. The antimicrobial resistance profile of the isolates was examined by using disc diffusion test.Results: Three hundred and seventy-eight Tn7-like-positive strains of Enterobacteriaceae were isolated, and included E. coli (128), Proteus(150), K. pneumonia(17), Salmonella(13), M. morganii (21) and A. baumannii(1), wherein high resistance was observed for Trimethoprim/Sulfamethoxazole and Streptomycin, and fifty percent of the strains were multidrug-resistant. Integrons class 2 were detected in all of the isolates and there are high frequency mutation sites especially in 535, a stop mutation. Variable region of class 2 integrons carried same gene cassettes, namely aadA1-sat2-dfrA1. From the 378 isolated strains, we found a new type of Tn7-like on a plasmid, named Tn6765.Conclusions: These findings proved that the Tn7-like can contribute to the horizontal transmission of antibiotic resistant genes in livestock and poultry. As potential vessels for antibiotic resistance genes (ARGs), Tn7-like could not be ignored due to their efficient transfer ability in environments.


2005 ◽  
Vol 68 (7) ◽  
pp. 1408-1413 ◽  
Author(s):  
SHIN-HEE KIM ◽  
CHENG-I WEI ◽  
HAEJUNG AN

Sixty-four multidrug-resistant isolates of Proteus mirabilis were collected from retail meat products in Oklahoma. The isolates showed four different patterns of antibiotic resistance based on their resistant phenotype and genotypes. Most of these isolates were resistant to ampicillin, tetracycline, gentamycin, and kanamycin. Class 1 integrons were detected as a common carrier of the antibiotic-resistant genes, such as aadA1, aadB, and aadA2. A few isolates (9%) contained class 2 integrons with three gene cassettes included: dhfr1, sat1, and aadA1. These isolates were even resistant to nalidixic acid due to mutations in gyrA and parC. All ampicillin-resistant isolates contained blaTEM-1. Plasmids that contained class 1 or 2 integrons and blaTEM-1 were able to be transferred from P. mirabilis isolates into Escherichia coli by conjugation, indicating that conjugal transfer could contribute to the dissemination of antibiotic resistance genes between the Enterobacteriaceae species.


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