Vibrio parahaemolyticus is a marine seafood-borne pathogen causing gastrointestinal disorders in humans. Thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) are known as major virulence determinants of V. parahaemolyticus. Most V. parahaemolyticus isolates from the environment do not produce TDH or TRH. Total V. parahaemolyticus has been used as an indicator for control of seafood contamination toward prevention of infection. Detection of total V. parahaemolyticus using conventional culture- and biochemical-based assays is time-consuming and laborious, requiring more than three days. Thus, we developed a novel and highly specific loop-mediated isothermal amplification (LAMP) assay for the sensitive and rapid detection of Vibrio parahaemolyticus.

We developed a loop-mediated isothermal amplification (LAMP) assay for the rapid and simple detection of Campylobacter jejuni and Campylobacter coli. The assay provides a specific LAMP product for each of these two species. The assay correctly identified 65 C. jejuni and 45 C. coli strains, but not 75 non-C. jejuni/coli strains. The sensitivity of the LAMP assay for C. jejuni and C. coli in spiked human stool specimens was 5.6×10³ c.f.u. g⁻¹ (1.4 c.f.u. per test tube) and 4.8×10³ c.f.u. g⁻¹ (1.2 c.f.u. per test tube), respectively. When 90 stool specimens from patients with diarrhoea were tested by LAMP and direct plating, the LAMP results showed 81.3 % sensitivity and 96.6 % specificity compared to isolation of C. jejuni and C. coli by direct plating. Further, the LAMP assay required less than 2 h for detection of C. jejuni and C. coli in stool specimens. This LAMP assay is a rapid and simple tool for the detection of C. jejuni and C. coli and will be useful in facilitating the early diagnosis of food poisoning incidents caused by these organisms.

We investigated the efficacy of a loop-mediated isothermal amplification (LAMP) assay for detection of chicken meat samples naturally contaminated with Campylobacter jejuni and Campylobacter coli . A total of 144 Preston enrichment broth cultures from chicken meat samples were assessed by using the LAMP assay and conventional culture methods, which consist of a combination of Preston enrichment culturing and plating onto Butzler and modified charcoal cefoperazone deoxycholate agars. Compared with C. jejuni - C. coli isolation using the conventional culture test, the LAMP results showed 98.5% (67/68) and 97.4% (74/76) sensitivity and specificity, respectively, and the positive and negative predictive values were 97.1% (67/69) and 98.7% (74/75), respectively. The conventional culture test required more than 3 to 4 days to isolate and identify C. jejuni and C. coli in the Preston enrichment cultures. In contrast, the LAMP assay was markedly faster, requiring less than 90 min from the beginning of DNA extraction to final detection and differentiation of C. jejuni and C. coli . In total, the LAMP assay required 23.5 to 25.5 h from the beginning of the enrichment culture to final determination. These results suggest that our LAMP assay is a powerful tool for rapid, sensitive, and practical detection of C. jejuni and C. coli which may facilitate surveillance and control of C. jejuni-C. coli contamination in chicken, as well as investigations of food poisoning incidents caused by these organisms. This is the first report of a highly sensitive and specific LAMP assay to detect and differentiate C. jejuni and C. coli in chicken meat samples.

Vibrio cholerae is widely acknowledged as one of the most important waterborne pathogen causing gastrointestinal disorders. Cholera toxin (CT) is a major virulence determinant of V. cholerae. Detection of CT-producing V. cholerae using conventional culture-, biochemical- and immunological-based assays is time-consuming and laborious, requiring more than three days. Thus, we developed a novel and highly specific loop-mediated isothermal amplification (LAMP) assay for the sensitive and rapid detection of cholera toxin (CT)-producing Vibrio cholerae.

Campylobacter fetus is a venereal pathogen of cattle and sheep, and an opportunistic human pathogen. It is often assumed that C. fetus infection occurs in humans as a zoonosis through food chain transmission. Here we show that mammalian C. fetus consists of distinct evolutionary lineages, primarily associated with either human or bovine hosts. We use whole-genome phylogenetics on 182 strains from 17 countries to provide evidence that C. fetus may have originated in humans around 10,500 years ago and may have “jumped” into cattle during the livestock domestication period. We detect C. fetus genomes in 8% of healthy human fecal metagenomes, where the human-associated lineages are the dominant type (78%). Thus, our work suggests that C. fetus is an unappreciated human intestinal pathobiont likely spread by human to human transmission. This genome-based evolutionary framework will facilitate C. fetus epidemiology research and the development of improved molecular diagnostics and prevention schemes for this neglected pathogen.