A systematic review and meta-analysis of integrated studies on antimicrobial resistance in Vietnam, with a focus on Enterobacteriaceae, from a One Health perspective

A review and meta-analysis of non-typhoidal Salmonella in Vietnam: Challenges to the control and antimicrobial resistance traits of a neglected zoonotic pathogen

Non-typhoidal Salmonella (NTS) is a food-borne zoonotic pathogen with important implications for human health. Despite its importance, the burden of NTS infections in Vietnam is unknown. We conducted a systematic review and a meta-analysis to describe the prevalence and phenotypic antimicrobial resistance (AMR) for NTS over time in Vietnam. Following PRISMA guidelines, we identified 72 studies from PubMed and Google Scholar containing data relevant to 'Salmonella', 'Salmonellosis', and 'Vietnam', or 'Viet Nam'. Of those, forty-two papers reporting prevalence of NTS, and twenty-six including data on phenotypic resistance were selected for meta-analysis. The prevalence of NTS ranged from 2% to 5% in humans and from 30% to 41% in samples from animals and the farm/slaughterhouse environment. Between 2000 and 2020 we observed a 27.3% (p = 0.044) increase in absolute terms in prevalence among individuals with enteric diseases and a 12.0% (p = 0.047) increase in aquaculture/seafood samples. The most commonly serovars identified across studies included S. Weltevreden (12.0%), followed by S. Typhimurium (10.1%), S. Derby (6.4%), S. London (5.8%), S. Anatum (4.4%), S. Rissen (3.9%), S. Enteritidis (3.7%), S. Albany (3.3%) and S. 4,[5],12:i:- (3.0%). Over the same period, there was an increasing trend in the pooled AMR prevalence for quinolones (15.6% relative increase), 3rd-, 4th-, and 5th-generation cephalosporins (23.7%), penicillins (16.1%), tetracyclines (12.9%), sulfonamides (8.8%), amphenicol (17.8%), and multidrug resistance (11.4%) (all p ≤ 0.014). A broad range of AMR genes (ARGs) were detected in both human and animal populations. The observed prevalence and AMR trends in Vietnam underscore the need of adopting a One Health strategy encompassing surveillance systems, research initiatives, and awareness campaigns to effectively address the challenges posed by NTS.

A systematic review and meta-analysis of the global prevalence and relationships among Burkholderia pseudomallei sequence types isolated from humans, animals, and the environment

Background and Aim

Burkholderia pseudomallei, a highly pathogenic bacterium responsible for melioidosis, exhibits ecological ubiquity and thrives within soil and water reservoirs, posing significant infection risks to humans and animals through direct contact. The aim of this study was to elucidate the genetic diversity and prevalence patterns of B. pseudomallei sequence types (STs) across a global spectrum and to understand the relationships between strains isolated from different sources.

Materials and Methods

We performed a systematic review and meta-analysis in this study. Extensive research was carried out across three comprehensive databases, including PubMed, Scopus, and ScienceDirect with data collected from 1924 to 2023.

Results

A total of 40 carefully selected articles contributed 2737 B. pseudomallei isolates attributed to 729 distinct STs and were incorporated into the systematic review. Among these, ST46 emerged as the most prominent, featuring in 35% of the articles and demonstrating a dominant prevalence, particularly within Southeast Asia. Moreover, ST51 consistently appeared across human, animal, and environmental studies. Subsequently, we performed a meta-analysis, focusing on nine specific STs: ST46, ST51, ST54, ST70, ST84, ST109, ST289, ST325, and ST376. Surprisingly, no statistically significant differences in their pooled prevalence proportions were observed across these compartments for ST46, ST70, ST289, ST325, and ST376 (all p > 0.69). Conversely, the remaining STs, including ST51, ST54, ST84, and ST109, displayed notable variations in their prevalence among the three domains (all p < 0.04). Notably, the pooled prevalence of ST51 in animals and environmental samples surpassed that found in human isolates (p < 0.01).

Conclusion

To the best of our knowledge, this study is the first systematic review and meta-analysis to investigate the intricate relationships between STs and their sources and contributes significantly to our understanding of B. pseudomallei diversity within the One Health framework.

Salmonella Typhimurium with Eight Tandem Copies of blaNDM-1 on a HI2 Plasmid

Carbapenem-resistant Salmonella has recently aroused increasing attention. In this study, a total of four sequence type 36 Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates were consecutively isolated from an 11-month-old female patient with a gastrointestinal infection, of which one was sensitive to carbapenems and three were resistant to carbapenems. Via antibiotic susceptibility testing, a carbapenemases screening test, plasmid conjugation experiments, Illumina short-reads, and PacBio HiFi sequencing, we found that all four S. Typhimurium isolates contained a blaCTX-M-14-positive IncI1 plasmid. One carbapenem-sensitive S. Typhimurium isolate then obtained an IncHI2 plasmid carrying blaNDM-1 and an IncP plasmid without any resistance genes during the disease progression. The blaNDM-1 gene was located on a new 30 kb multiple drug resistance region, which is flanked by IS26 and TnAs2, respectively. In addition, the ST_F0903R isolate contained eight tandem copies of the ISCR1 unit (ISCR1-dsbD-trpF-ble-blaNDM-1-ISAba125Δ1), but an increase in MICs to carbapenems was not observed. Our work further provided evidence of the rapid spread and amplification of blaNDM-1 through plasmid. Prompting the recognition of carbapenem-resistant Enterobacterales and the initiation of appropriate infection control measures are essential to avoid the spread of these organisms.

Antimicrobial resistance and biofilm formation of Escherichia coli in a Vietnamese Pangasius fish processing facility

This study aimed to investigate the occurrence, antibiotic resistance, and biofilm formation of Escherichia coli in the Vietnamese Pangasius fish processing facility. Among 144 samples including Pangasius fish, wash water, food contact surfaces, and personnel gloves, 18 E. coli isolates was detected and characterized. The E. coli was detected most frequently in wash water samples (22%, 8/36), followed by Pangasius fish (18%, 8/45). According to the antibiotic susceptibility test by the disc diffusion method, isolates showed the highest resistance against sulfamethoxazole/trimethoprim (45%), followed by tetracycline (39%), whereas all the E. coli isolates were susceptible to meropenem and fosfomycin. Notably, 39% of the isolates (7/18) were found to be multidrug resistant while no E. coli isolates were confirmed as extended-spectrum β-lactamase producers by the double-disk synergy test. The potency to form biofilm on the polystyrene surface of E. coli isolates indicated that 44% of the isolates (8/18) were classified as weak, 39% (7/18) as moderate, and 17% (3/18) as strong biofilm formers. Interestingly, multidrug resistant E. coli isolates were observed in moderate and strong biofilm producers. Additionally, either slightly acidic hypochlorous water with 40 mg/L of available chlorine or sodium hypochlorite with 100 mg/L of available chlorine exhibited a significant reduction in biofilm mass and biofilm cells of E. coli isolates. This study may provide helpful information about the actual state of E. coli isolates for effective control in the fish processing plant.