Antimicrobial resistance gene expression associated with multidrug resistant Salmonella spp. isolated from retail meat in Hanoi, Vietnam.

The purpose of this study was to further characterize the multi-antimicrobial resistance and antibiotic resistance gene expression associated with multi-drug resistance (MDR) in Salmonella spp. isolates from retail meats in Hanoi, Vietnam. A total of 14 Salmonella spp. belonging to 9 serotypes (e.g., Warragul, London, Derby, Indiana, Meleagridis, Give, Rissen, Assine, and Typhimurium) were tested for sensitivity to 8 antibiotics. Resistance to at least one antibiotic was shown in 13 strains (92.85%). The multiple antimicrobial resistances accounted for 64.29% of isolates (9/14). One hundred percent of MDR isolates possessed antibiotic resistant genes, in which 17, 16 and 11 genes were found in Salmonella (Salm) Typhimurium S360, S384, S181 respectively; 12 genes in each strain as Indiana, Warragul, and Meleagridis; 11 genes in Give, 8 genes in Derby and 6 genes in Rissen. Three antibiotic resistance genes (ssaQ, aadA, and gyrB) were present in all isolates, whereas Cephalosporin-resistant gene (e.g., CTX-M3-like) was not detected in any isolates. The results suggest that retail meats could constitute a source of human exposure to multi-drug resistant Salmonella and future research should focus on the impact of these MDR source on the human genome. [Int Microbiol 20(2): 85-93 (2017)].

Antimicrobial resistance gene expression associated with multidrug resistant Salmonella spp isolated from retail meat in Hanoi, Vietnam

The purpose of this study was to further characterize the multi-antimicrobial resistance and antibiotic resistance gene expression associated with multi-drug resistance (MDR) in Salmonella spp. isolates from retail meats in Hanoi, Vietnam. A total of 14 Salmonella spp. belonging to 9 serotypes (e.g., Warragul, London, Derby, Indiana, Meleagridis, Give, Rissen, Assine, and Typhimurium) were tested for sensitivity to 8 antibiotics. Resistance to at least one antibiotic was shown in 13 strains (92.85%). The multiple antimicrobial resistances accounted for 64.29% of isolates (9/14). One hundred percent of MDR isolates possessed antibiotic resistant genes, in which 17, 16 and 11 genes were found in Salmonella (Salm) Typhimurium S360, S384, S181 respectively; 12 genes in each strain as Indiana, Warragul, and Meleagridis; 11 genes in Give, 8 genes in Derby and 6 genes in Rissen. Three antibiotic resistance genes (ssaQ, aadA, and gyrB) were present in all isolates, whereas Cephalosporinresistant gene (e.g., CTX-M3-like) was not detected in any isolates. The results suggest that retail meats could constitute a source of human exposure to multi-drug resistant Salmonella and future research should focus on the impact of these MDR source on the human genome (AU)

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A Simple, Single Triplex PCR of IS6110, IS1081, and 23S Ribosomal DNA Targets, Developed for Rapid Detection and Discrimination of Mycobacterium from Clinical Samples.

Tuberculosis (TB) is the most common mycobacterial infection in developing countries, requiring a rapid, accurate, and well-differentiated detection/diagnosis. For the rapid detection and discrimination of Mycobacterium tuberculosis complex (MTC) from nontuberculous mycobacteria (NTM), a novel, simple, and primer-combined single-step multiplex PCR using three primer pairs (6110F-6110R, 1081F-1081R, and 23SF-23SR; annealing on each of IS6110, IS1081, and 23S rDNA targets), hereafter referred to as a triplex PCR, has been developed and evaluated. The expected product for IS6110 is 416 bp, for IS1081 is 300 bp, and for 23S rDNA is 206 bp by single PCR, which was used to verify the specificity of primers and the identity of MTC using DNA extracted from the M. tuberculosis H37Rv reference strain (ATCC, USA) and other mycobacteria other than tuberculosis (MOTT) templates. The triplex PCR assay showed 100% specificity and 96% sensitivity; the limit of detection for mycobacteria was ~100 fg; and it failed to amplify any target from DNA of MOTT (50 samples tested). Of 307 blinded clinical samples, overall 205 positive M. tuberculosis samples were detected by single PCR, 142 by conventional culture, and 90 by AFB smear methods. Remarkably, the triplex PCR could subsequently detect 55 positive M. tuberculosis from 165 culture-negative and 115 from 217 AFB smear-negative samples. The triplex PCR, targeting three regions in the M. tuberculosis genome, has proved to be an efficient tool for increasing positive detection/ discrimination of this bacterium from clinical samples.

Viral distribution and life strategies in the Bach Dang Estuary, Vietnam.

Although the structure and dynamics of planktonic viruses in freshwater and seawater environments are relatively well documented, little is known about the occurrence and activity of these viruses in estuaries, especially in the tropics. Viral abundance, life strategies, and morphotype distribution were examined in the Bach Dang Estuary (Vietnam) during the dry season in 2009. The abundance of both viruses and their prokaryotic hosts decreased significantly from upstream to downstream, probably as the result of nutrient dilution and osmotic stress faced by the freshwater communities. The antibiotic mitomycin-C revealed that the fraction of lysogenic cells was substantially higher in the lower seawater part of the estuary (max 27.1%) than in the upper freshwater area where no inducible lysogens were observed. The question of whether there is a massive, continuous induction of marine lysogens caused by the mixing with freshwater is considered. Conversely, the production of lytic viruses declined as salinity increased, indicating a spatial succession of viral life strategies in this tropical estuary. Icosahedral tailless viruses with capsids smaller than 60 nm dominated the viral assemblage throughout the estuary (63.0% to 72.1% of the total viral counts), and their distribution was positively correlated with that of viral lytic production. Interestingly, the gamma-proteobacteria explained a significant portion of the variance in the <60 nm and 60 to 90 nm tailless viruses (92% and 80%, respectively), and in the Myoviridae (73%). Also, 60% of the variance of the tailless larger viruses (>90 nm) was explained by the beta-proteobacteria. Overall, these results support the view that the environment, through selection mechanisms, probably shapes the structure of the prokaryotic community. This might be in turn a source of selection for the virioplankton community via specific affiliation favoring particular morphotypes and life strategies.