Detection of chromosome-mediated blaNDM-1-carrying Aeromonas spp. in the intestinal contents of fresh water river fish in Ho Chi Minh City, Vietnam.

The spread of antibiotic-resistant bacteria is a global problem that should be addressed through the perspective of the "one health" concept. The purpose of this study was to determine the contamination rate of antibiotic-resistant Aeromonas spp. in fresh water river fish purchased from a fish market in Vietnam. We then defined the pattern of antibiotic resistance to assess antibiotic-resistant contamination. Antibiotic-resistant Aeromonas spp. were detected in the intestinal contents of 32 of 80 fish. blaNDM-1 was detected in seven strains. Extended-spectrum ß-lactamase and AmpC ß-lactamase-related genes were detected in 28 strains, including blaCTX-M-55, blaCTX-M-15, blaCTX-M-1, and blaDHA,blaFOX, and blaMOX. The blaNDM-1 detected in the seven Aeromonas spp. strains were found chromosomally. This finding suggests that the blaNDM gene is stable in the natural environment and may spread widely into animals and humans via Aeromonas spp. with a transposon. Our results suggest the importance of continuing to monitor carbapenemase genes in Aeromonas spp. to evaluate the possibility that they may spread in other Enterobacterales, and to elucidate the mechanism of spread.

Early centralized isolation strategy for all confirmed cases of COVID-19 remains a core intervention to disrupt the pandemic spreading significantly.

BACKGROUND: In response to the spread of the coronavirus disease 2019 (COVID-19), plenty of control measures were proposed. To assess the impact of current control measures on the number of new case indices 14 countries with the highest confirmed cases, highest mortality rate, and having a close relationship with the outbreak's origin; were selected and analyzed. METHODS: In the study, we analyzed the impact of five control measures, including centralized isolation of all confirmed cases, closure of schools, closure of public areas, closure of cities, and closure of borders of the 14 targeted countries according to their timing; by comparing its absolute effect average, its absolute effect cumulative, and its relative effect average. RESULTS: Our analysis determined that early centralized isolation of all confirmed cases was represented as a core intervention in significantly disrupting the pandemic's spread. This strategy helped in successfully controlling the early stage of the outbreak when the total number of cases were under 100, without the requirement of the closure of cities and public areas, which would impose a negative impact on the society and its economy. However, when the number of cases increased with the apparition of new clusters, coordination between centralized isolation and non-pharmaceutical interventions facilitated control of the crisis efficiently. CONCLUSION: Early centralized isolation of all confirmed cases should be implemented at the time of the first detected infectious case.

Enterococcus saigonensis sp. nov., isolated from retail chicken meat and liver.

Two Gram-stain-positive strains, VE80T and VE116, which were resistant to vancomycin, were isolated from retail chicken meat and liver in Ho Chi Minh, Vietnam, respectively. These strains were characterized by sequence analyses of 16S rRNA, RNA polymerase α-subunit (rpoA), ATP synthase α-subunit (atpA), and phenylalanyl-tRNA synthase α-subunit (pheS) genes, determination of DNA G+C content, cellular fatty acid methyl ester analysis, DNA-DNA hybridization, and conventional morphological and biochemical tests. Strains VE80T and VE116 had 99.6 % 16S rRNA gene sequence similarity with Enterococcus canintestini LMG 13590T, and 99.1 % 16S rRNA gene sequence similarity with Enterococcus dispar ATCC 51266T. However, the two isolates could be clearly differentiated from these reference strains by the low sequence similarities (86.1-86.8 %) of the atpA gene, low DNA-DNA relatedness (<22.8 %), and differences in the production of acid from melezitose and methyl α-d-glucoside. Based on the results obtained in the present study, these two isolates are considered to represent a novel species of the genus Enterococcus, for which the name Enterococcus saigonensis sp. nov., is proposed. The type strain is VE80T (=JCM 31193T=CCUG 68827T).

Dissemination of Extended-Spectrum ß-Lactamase- and AmpC ß-Lactamase-Producing Escherichia coli within the Food Distribution System of Ho Chi Minh City, Vietnam.

To investigate the dissemination of ESBL/pAmpC-producing E. coli within the food distribution system of Ho Chi Minh City (HCMC), Vietnam, the prevalence of ESBL/pAmpC-producing E. coli strains in chicken meat, pork, beef, and fish/shrimp samples obtained from slaughterhouses, a wholesale market, and supermarkets was examined. Among the total of 330 collected food samples, ESBL/pAmpC-producing E. coli was detected in 150 samples (45.5%). The highest prevalence of these isolates was in chicken meat (76/82, 92.7%), followed by pork (32/92, 34.8%), beef (18/74, 34.3%), and fish/shrimp (24/82, 29.3%). A total of 342 strains of ESBL/pAmpC-producing E. coli were isolated from 150 positive food samples. The most prevalent genes responsible for ESBL or pAmpC activity belonged to the CTX-M-9 (110/342, 31.2%), CTX-M-1 (102/342, 29.8%), and CIT (118/342, 34.5%) groups. To our knowledge, this is the first report of the high occurrence of pAmpC (37.1%) in animal-based food in Vietnam. Among the 342 total ESBL/pAmpC-producing E. coli isolates, 276 (80.7%) were resistant to at least 6 antibiotic agents. Notably, high percentages of resistance to ciprofloxacin and fosfomycin were found in isolates from chicken (80.5% and 50.8%, resp.). These findings demonstrate that animal-based food products in HCMC represent a major reservoir of ESBL/pAmpC-producing E. coli.

Prevalence and Antimicrobial Susceptibility of Enterobacteriaceae Isolated from Retail Pepper in Vietnam.

To investigate the microbial quality of retail pepper in Vietnam, the enumeration and detection of Enterobacteriaceae and the screening of cefotaxime (CTX)-resistant coliforms were performed by using 84 commercial samples. Although Enterobacteriaceae were isolated from 78 samples, the number of Enterobacteriaceae was lower than 1.0 log CFU/g in 46 samples. For the detection of Enterobacteriaceae with the International Organization for Standardization methods, Salmonella spp., Escherichia coli, Klebsiella pneumoniae, Cronobacter sakazakii, and Enterobacter cloacae complex were isolated from 5, 12, 36, 19, and 30 samples, respectively. During screening of CTX-resistant coliforms, K. pneumoniae, C. sakazakii, and E. cloacae complex were isolated from 8, 1, and 21 samples, respectively. Seven K. pneumoniae and seven E. cloacae complex isolates obtained in the screening of CTX-resistant coliforms were resistant to at least one of the three third-generation cephalosporins (CTX, ceftazidime, and cefpodoxime). Moreover, one E. cloacae complex cluster IV and all K. pneumoniae isolates were positive for extended-spectrum ß-lactamase genes or plasmid-mediated AmpC ß-lactamase genes or both. Additionally, two extended-spectrum ß-lactamase-producing K. pneumoniae isolates and one AmpC ß-lactamase-producing E. cloacae complex cluster IV isolate were positive for the plasmid-mediated quinolone resistance determinants and also had amino acid alterations in the quinolone resistance-determining regions of GyrA and ParC. Furthermore, 10 E. cloacae complex isolates were positive for the plasmid-mediated fosfomycin resistance gene fosA. As pepper is often consumed without a heating process, the possible spread to humans of foodborne, opportunistic, and nosocomial infection pathogens or resistance genes from foods prepared or seasoned with pepper cannot be excluded. Therefore, it is necessary to handle pepper by using hygienic conditions during the cultivation, harvesting and processing steps.