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Cholera is still an important public health problem in several countries, including Thailand. In this study, a collection of clinical and environmental V. cholerae serogroup O1, O139, and non-O1/non-O139 strains originating from Thailand (1983 to 2013) was characterized to determine phenotypic and genotypic traits and to investigate the genetic relatedness. Using a combination of conventional methods and whole genome sequencing (WGS), 78 V. cholerae strains were identified. WGS was used to determine the serogroup, biotype, virulence, mobile genetic elements, and antimicrobial resistance genes using online bioinformatics tools. In addition, phenotypic antimicrobial resistance was determined by the minimal inhibitory concentration (MIC) test. The 78 V. cholerae strains belonged to the following serogroups O1: (n = 44), O139 (n = 16) and non-O1/non-O139 (n = 18). Interestingly, we found that the typical El Tor O1 strains were the major cause of clinical cholera during 1983-2000 with two Classical O1 strains detected in 2000. In 2004-2010, the El Tor variant strains revealed genotypes of the Classical biotype possessing either only ctxB or both ctxB and rstR while they harbored tcpA of the El Tor biotype. Thirty O1 and eleven O139 clinical strains carried CTXϕ (Cholera toxin) and tcpA as well four different pathogenic islands (PAIs). Beside non-O1/non-O139, the O1 environmental strains also presented chxA and Type Three Secretion System (TTSS). The in silico MultiLocus Sequence Typing (MLST) discriminated the O1 and O139 clinical strains from other serogroups and environmental strains. ST69 was dominant in the clinical strains belonging to the 7th pandemic clone. Non-O1/non-O139 and environmental strains showed various novel STs indicating genetic variation. Multidrug-resistant (MDR) strains were observed and conferred resistance to ampicillin, azithromycin, nalidixic acid, sulfamethoxazole, tetracycline, and trimethoprim and harboured variants of the SXT elements. For the first time since 1986, the presence of V. cholerae O1 Classical was reported causing cholera outbreaks in Thailand. In addition, we found that V. cholerae O1 El Tor variant and O139 were pre-dominating the pathogenic strains in Thailand. Using WGS and bioinformatic tools to analyze both historical and contemporary V. cholerae circulating in Thailand provided a more detailed understanding of the V. cholerae epidemiology, which ultimately could be applied for control measures and management of cholera in Thailand.

Background: The global emergence and spread of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales, especially Escherichia coli and Klebsiella pneumoniae, have been recognized as a public health concern as severe infections caused by these microorganisms increase morbidity and mortality. This study aimed to assess the prevalence of ESBL-positive E. coli and K. pneumoniae strains isolated from hospitalized patients in Chiangrai Prachanukroh hospital, Chiangrai province, Thailand.Methods: This retrospective analysis was conducted from January 2016 to December 2020. A total of 384,001 clinical specimens were collected aseptically and further cultivated on an appropriate medium. All clinical isolates (one isolate per patient) were identified based on standard laboratory methods. Antibiotic susceptibility testing was performed by the Kirby Bauer disc diffusion technique following CLSI guidelines. ESBL production was screened with ceftazidime and cefotaxime discs based on the CLSI recommendations. Phenotypic confirmation of ESBL production was carried out using a double-disc synergy technique following the CLSI standard.Results: Of a total of 384,001 clinical samples analyzed for bacterial species identification, 11,065 (2.9%) tested positive for E. coli and 5,617 (1.5%) for K. pneumoniae. Approximately 42.5% (4,706/11,065) of E. coli and 30.2% (1,697/5,617) of K. pneumoniae isolates were classified as ESBL producers. A higher proportion of ESBL producers was found in patients older than 60 years and male groups. The highest infection rates of ESBL-positive pathogens were observed among patients in a medical unit. ESBL-producing E. coli and K. pneumoniae isolates were predominantly found in urine and sputum, respectively. ESBL producers exhibited a high resistance rate to ampicillin (99.8–100%), cefazolin (100%), cefotaxime (100%), fluoroquinolones, and trimethoprim/sulfamethoxazole.Conclusions: This study demonstrated the high prevalence and emerging antibiotic resistance of ESBL-positive E. coli and K. pneumoniae isolates from patients admitted to a provincial hospital in northern Thailand. Most ESBL-producing strains were highly resistant to several antimicrobial agents apart from carbapenems and aminoglycosides. These findings indicated that carbapenems and aminoglycosides should be advised as the first-line drugs of choice for serious infections with ESBL-producing Enterobacterales.

The spread of multidrug-resistant (MDR) Vibrio cholerae necessitates the development of novel prevention and treatment strategies. This study aims to evaluate the in vitro antibacterial activity of green tea polyphenol (−)-epigallocatechin-3-gallate (EGCG) against MDR V. cholerae. First, MIC and MBC values were evaluated by broth microdilution techniques against 45 V. cholerae strains. The checkerboard assay was then used to determine the synergistic effect of EGCG and tetracycline. The pharmaceutical mode of action of EGCG was clarified by time-killing kinetics and membrane disruption assay. Our results revealed that all of the 45 clinical isolates were susceptible to EGCG, with MIC and MBC values in the range of 62.5–250 µg/mL and 125–500 µg/mL, respectively. Furthermore, the combination of EGCG and tetracycline was greater than either treatment alone, with a fractional inhibitory concentration index (FICI) of 0.009 and 0.018 in the O1 and O139 representative serotypes, respectively. Time-killing kinetics analysis suggested that EGCG had bactericidal activity for MDR V. cholerae after exposure to at least 62.5 µg/mL EGCG within 1 h. The mode of action of EGCG might be associated with membrane disrupting permeability, as confirmed by scanning electron microscopy. This is the first indication that EGCG is a viable anti-MDR V. cholerae treatment.

Computer devices in university settings are frequently shared and repeatedly handled, making them potential reservoirs for pathogenic bacteria. This study aimed to investigate the prevalence, virulence determinants, and antimicrobial resistance profiles of Staphylococcus aureus and Escherichia coli isolated from computer devices used by staff and students at a university in Northern Thailand. A total of 400 computer devices were sampled, with each device defined as a single sampling unit comprising both the keyboard and computer mouse. Bacterial identification was performed using PCR, while staphylococcal enterotoxin (se) genes and diarrheagenic E. coli (DEC)-associated virulence genes were detected by PCR. Antimicrobial susceptibility was assessed using the disk diffusion method. Overall, 74 (18.5%) S. aureus isolates and 6 (1.5%) E. coli isolates were recovered. The highest prevalence of S. aureus was observed among personal-use student computer devices (29%; p < 0.001), whereas E. coli was most frequently detected on public-use staff computer devices (4%). Among S. aureus isolates, 24.3% (18/74) carried at least one se gene, with sec being the most prevalent (13.5%). Half of the E. coli isolates harbored the astA gene. Low resistance rates (<10%) were observed among S. aureus; however, four isolates (5.4%) were classified as MRSA, three of which exhibited multidrug resistance. All E. coli isolates were resistant to ampicillin, and 50% displayed multidrug-resistant phenotypes. These findings suggest that computer devices can act as occasional reservoirs of potentially pathogenic and antimicrobial-resistant bacteria in university environments.

Background Mobile phones are widely used and may cause bacterial pathogens to spread among various professionals. Staphylococcus aureus from the mobile phones can contaminate the hands of food vendors and food during the cooking or packaging process. This research aimed to determine the prevalence, enterotoxin genes, and antimicrobial resistance (AMR) profiles of S. aureus contaminating the vendors’ mobile phones. Methods In this study, 266 mobile phone samples were randomly collected from food vendors selling food on walking streets (n = 139) and in food centers (n = 127) in Phayao province. All samples were identified as S. aureus by the conventional culture method and confirmed species-specific gene by polymerase chain reaction (PCR). Then, all identified S. aureus isolates were tested for antimicrobial susceptibility by broth microdilution method and for the presence of staphylococcal enterotoxin (SE) genes by PCR. Results The results showed that 12.8% of the mobile phones collected were contaminated with S. aureus . Of 49 S. aureus isolates obtained, 30 (61.2%) were positive for SE genes. The most common SE gene was sea followed by sec , seb , sem , seq , and sel . Moreover, S. aureus was most frequently resistant to penicillin, followed by chloramphenicol and tetracycline, erythromycin, clindamycin, and gentamicin. Methicillin-resistant S. aureus (MRSA), vancomycin-resistant S. aureus (VRSA), and multidrug - resistant (MDR) strains were also detected. Conclusions This study showed that mobile phones were an intermediate surface for the transmission of S. aureus , including MDR variants. It indicates that hand hygiene and the decontamination of mobile phones are essential to prevent cross-contamination of S. aureus in food settings.

Northern Thai culture offers a rich variety of traditional fermented foods beneficial for gastrointestinal health. In this study, we characterized lactic acid bacteria (LAB) from various indigenous fermented foods as potential probiotic candidates and determined their properties for application in commercial synbiotic formulation. Five isolates demonstrating high tolerance to low pH (2.0) and 0.3% bile salts were collected and characterized. These included three strains of Lactiplantibacillus plantarum isolated from nham (NB1, NP2, and NP11) and two strains of Limosilactobacillus fermentum isolated from pla-som (PS4 and PS7). All the selected LAB isolates exhibited γ-hemolytic activity, strong antimicrobial activity, and high resistance to gastric and duodenal digestion conditions. Among the LAB isolates, L. plantarum NB1 demonstrated the highest capacity for adhesion to Caco-2 cells, auto-aggregation, and antioxidant activity, differing significantly (p < 0.05) from the other isolates. Furthermore, the NB1 strain exhibited preferential growth in the presence of commercial prebiotics (fructooligosaccharide, lactose, and inulin) and good survival after lyophilization, which is a desirable characteristic for a powdered ingredient. Therefore, the NB1 strain is a suitable probiotic candidate for applications in synbiotic formulation or as a functional food ingredient.

Multidrug-resistant (MDR) bacteria, especially Escherichia coli, are a major contributor to healthcare-associated infections globally, posing significant treatment challenges. This study explores the efficacy of (−)-epigallocatechin gallate (EGCG), a natural constituent of green tea, in combination with ampicillin (AMP) to restore the effectiveness of AMP against 40 isolated MDR E. coli strains. Antimicrobial activity assays were conducted to determine the minimum inhibitory concentrations (MIC) of EGCG using the standard microdilution technique. Checkerboard assays were employed to assess the potential synergistic effects of EGCG combined with AMP. The pharmacodynamic effects of the combination were evaluated through time-kill assays. Outer membrane disruption was analyzed by measuring DNA and protein leakage and with assessments using N-phenyl-1-naphthylamine (NPN) and rhodamine 123 (Rh123) fluorescence dyes. Biofilm eradication studies involved biofilm formation assays and preformed biofilm biomass and viability assays. Scanning electron microscopy (SEM) was used to examine changes in cellular morphology. The results indicated that EGCG demonstrated activity against all isolates, with MICs ranging from 0.5 to 2 mg/mL, while AMP exhibited MIC values between 1.25 and 50 mg/mL. Importantly, the EGCG-AMP combination showed enhanced efficacy compared to either treatment alone, as indicated by a fractional inhibitory concentration index between 0.009 and 0.018. The most pronounced synergy was observed in 13 drug-resistant strains, where the MIC for EGCG dropped to 8 µg/mL (from 1 mg/mL alone) and that for AMP to 50 µg/mL (from 50 mg/mL alone), achieving a 125-fold and 1000-fold reduction, respectively. Time-kill assays revealed that the bactericidal effect of the EGCG-AMP combination occurred within 2 h. The mechanism of EGCG action includes the disruption of membrane permeability and biofilm eradication in a dose-dependent manner. SEM confirmed that the combination treatment consistently outperformed the individual treatments. This study underscores the potential of restoring AMP efficacy in combination with EGCG as a promising strategy for treating MDR E. coli infections.

Extensively drug-resistant (XDR) Acinetobacter baumannii poses a serious clinical challenge due to its resistance to nearly all available antibiotics, including carbapenems and colistin. Cannabidiol (CBD), a non-psychoactive phytochemical from Cannabis sativa L., has recently shown promising antimicrobial activity. This study evaluates the antibacterial and anti-biofilm effects of CBD against XDR A. baumannii isolates and explores its mechanism of action and potential as an adjunct therapeutic agent. Twenty-six A. baumannii isolates collected from ICU medical devices were identified using MALDI-TOF/MS. Antimicrobial susceptibility was assessed by disk diffusion and broth microdilution to determine MICs and MBCs for CBD and standard antibiotics. Synergistic effects were evaluated via checkerboard assays and FICI values. Biofilm inhibition and eradication were assessed using crystal violet and MTT assays. Time-kill studies, membrane integrity assays (DNA/protein leakage, NPN uptake, membrane depolarization), and scanning electron microscopy (SEM) were employed to investigate bactericidal kinetics and membrane-disruptive mechanisms. CBD exhibited activity against antimicrobial resistance isolates (MIC: 3.9 to > 500 µg/mL). Remarkably, CBD synergized with gentamicin, meropenem, and colistin, reducing their effective concentrations by up to 1,000-fold. Combination therapy significantly inhibited and eradicated biofilms. Time-kill assays demonstrated rapid, concentration-dependent killing, with complete bacterial clearance at 4× MIC within 2 h. Mechanistic assays and SEM confirmed that CBD induces extensive membrane damage. These findings highlight CBD’s potential as an effective adjunct to conventional antibiotics for treating XDR A. baumannii infections, offering a novel strategy to counteract antimicrobial resistance.

The prevalence of reported cholera was relatively low around the Lake Chad basin until 1991. Since then, cholera outbreaks have been reported every couple of years. The objective of this study was to investigate the 2010/2011 Vibrio cholerae outbreak in Cameroon to gain insight into the genomic make-up of the V. cholerae strains responsible for the outbreak. Twenty-four strains were isolated and whole genome sequenced. Known virulence genes, resistance genes and integrating conjugative element (ICE) elements were identified and annotated. A global phylogeny (378 genomes) was inferred using a single nucleotide polymorphism (SNP) analysis. The Cameroon outbreak was found to be clonal and clustered distant from the other African strains. In addition, a subset of the strains contained a deletion that was found in the ICE element causing less resistance. These results suggest that V. cholerae is endemic in the Lake Chad basin and different from other African strains.

Lung cancer, especially non-small cell lung cancer (NSCLC), is one of the most complex diseases, despite the existence of effective treatments such as chemotherapy and immunotherapy. Since cancer stem cells (CSCs) are responsible for chemo- and radio-resistance, metastasis, and cancer recurrence, finding new therapeutic targets for CSCs is critical. Dinactin is a natural secondary metabolite produced by microorganisms. Recently, dinactin has been revealed as a promising antitumor antibiotic via various mechanisms. However, the evidence relating to cell cycle progression regulation is constrained, and effects on cancer stemness have not been elucidated. Therefore, the aim of this study is to evaluate the new function of dinactin in anti-NSCLC proliferation, focusing on cell cycle progression and cancer stemness properties in Lu99 and A549 cells. Flow cytometry and immunoblotting analyses revealed that 0.1–1 µM of dinactin suppresses cell growth through induction of the G0/G1 phase associated with down-regulation of cyclins A, B, and D3, and cdk2 protein expression. The tumor-sphere forming capacity was used to assess the effect of dinactin on the cancer stemness potential in NSCLC cells. At a concentration of 1 nM, dinactin reduced both the number and size of the tumor-spheres. The quantitative RT-PCR analyses indicated that dinactin suppressed sphere formation by significantly reducing expression of CSC markers (i.e., ALDH1A1, Nanog, Oct4, and Sox2) in Lu99 cells. Consequently, dinactin could be a promising strategy for NSCLC therapy targeting CSCs.