Prevalence, virulence characteristics, and antimicrobial resistance of Vibrio parahaemolyticus isolates from raw seafood in a province in Northern Thailand

Vibrio parahaemolyticus (V. parahaemolyticus) is commonly found in seawater and seafood products, but evidence is limited of its presence in seafood marketed in locations very distant from coastal sources. This study determined the prevalence and characterization of V. parahaemolyticus in seafood from markets in landlocked Phayao province, Northern Thailand. Among 120 samples, 26 (21.7%) were positive for V. parahaemolyticus, being highest in shrimp (43.3%), followed by shellfish (36.7%), and squid (6.7%), but was not found in fish. V. parahaemolyticus comprised 33 isolates that were non-pathogenic and non-pandemic. Almost all isolates from shrimp and shellfish samples were positive for T3SS1. Only five isolates (15.2%) showed two antimicrobial resistance patterns, namely, kanamycin-streptomycin (1) carrying sul2 and ampicillin-kanamycin-streptomycin (4) that carried tetA (2), tetA-sul2 (1), as well as one negative. Antimicrobial susceptible V. parahaemolyticus isolates possessing tetA (67.9%) and sul2 (3.5%) were also found. Six isolates positive for integron class 1 and/or class 2 were detected in 4 antimicrobial susceptible and 2 resistant isolates. While pathogenic V. parahaemolyticus was not detected, contamination of antimicrobial resistance V. parahaemolyticus in seafood in locations distant from coastal areas requires ongoing monitoring to improve food safety in the seafood supply chain.

Exploration of the novel fluoroquinolones with high inhibitory effect against quinolone-resistant DNA gyrase of Salmonella Typhimurium

IMPORTANCE

Quinolone-resistant nontyphoidal Salmonella is a pressing public health concern, demanding the exploration of novel treatments. In this study, we focused on two innovative synthetic fluoroquinolones, WQ-3034 and WQ-3154. Our findings revealed that these new compounds demonstrate potent inhibitory effects, even against mutant strains that cause resistance to existing quinolones. Hence, WQ-3034 and WQ-3154 could potentially be effective therapeutic agents against quinolone-resistant Salmonella Typhimurium. Furthermore, the data obtained in this study will be baseline information for antimicrobial drug development.

Prevalence, antimicrobial resistance, and enterotoxin gene profiles of Staphylococcus aureus isolated from mobile phones of the food vendors in Phayao province, Thailand

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.

Direct detection of Mycobacterium bovis by a dry loop-mediated isothermal amplification assay in cattle samples collected during routine abattoir examination in Malawi

The lack of quick, accurate, and low-cost detection methods has hindered the active control strategies for bovine tuberculosis (bTB) in resource-limited countries with a high burden of disease. We developed a dry loop-mediated isothermal amplification (LAMP) assay for rapid and specific detection of Mycobacterium bovis, the principal causative agent of bTB, and evaluated the efficacy of the assay using suspected bTB samples collected during routine meat inspection at major regional abattoirs in Malawi. Template genomic DNA was extracted directly from the granulomatous bTB-like lesion (crude extracted DNA), as well as growth from the incubated mycobacterial growth indicator tubes (MGIT). Field results were visualized by the naked eye within 40 min following a color change of the amplified products. The sensitivity and specificity of the dry LAMP assay while using 152 DNA samples extracted from MGIT with confirmed M. bovis results were 98% and 88%, respectively. When 43 randomly selected crude DNA samples from lesions were used, the sensitivity and specificity of the dry LAMP assay were 100% and 75%, respectively. Our LAMP assay offers the potential to meet the demands for a low-cost and rapid field detection tool for bTB in resource-limited countries in which bTB is endemic.