Detection of non-culturable Shigella dysenteriae 1 from artificially contaminated volunteers' fingers using fluorescent antibody and PCR techniques.

Epidemiological studies have demonstrated that hands may be an important vehicle for transmission of shigellosis. The present study was carried out to find out the survival potential of Shigella dysenteriae 1 on fingers of volunteers. Finger surface was inoculated with 10(5) cfu of S. dysenteriae 1 and then the bacteria were detected using conventional culture, PCR and fluorescent antibody (FA) techniques after different time intervals. It was found that S. dysenteriae 1 survived for up to one hour in culturable form but up to four hours in non-culturable form on human fingers. The non-culturable S. dysenteriae was detected by PCR and FA techniques. This study elaborates on the role that fingers have in the transmission of shigellae.

Spatial distribution of watery diarrhoea in children: identification of "risk areas" in a rural community in Bangladesh.

To assess the geographic variation of acute watery diarrhoea in children 0 to 5 years old in rural Bangladesh, all cases of "cholera-like" diarrhoea were plotted on the map. A clustering pattern was noticed, and validated by a nonparametric clustering test for in-homogeneous population. Several risk areas for the disease were identified. In these areas, the point prevalence (8.7/1000) was notably higher than outside the areas (0.41/1000), (95% confidence interval, 15.55-29.30). Parents' education, population density and use of sanitary latrines were significantly related to the risk areas (p < or = 0.001). The results of this study indicate that computer-assisted mapping may be useful in defining and monitoring risk areas for watery diarrhoea in children.

Short communication: Detection of non-culturable Vibrio cholerae O139, by PCR and fluorescent antibody methods, in laboratory microcosms.

Non-culturable Vibrio cholerae O139 was detected in microcosms by PCR and fluorescent-antibody (FA) techniques. When survival of V. cholerae O139 in microcosms was assessed by viable counting on culture media, the vibrio became non-culturable after 44 days and remained non-culturable for an additional 7 weeks.

Use of the polymerase chain reaction and fluorescent-antibody methods for detecting viable but nonculturable Shigella dysenteriae type 1 in laboratory microcosms.

Epidemiological studies of shigellosis in Bangladesh have demonstrated that surface-water sources can act as foci of infection. Studies of laboratory microcosms have shown that shigellae become nonculturable but remain viable when exposed to environmental samples of water. The present study was carried out to detect viable but nonculturable Shigella dysenteriae 1 from laboratory microcosms by the polymerase chain reaction and the fluorescent-antibody techniques. S. dysenteriae 1 was inoculated into laboratory microcosms consisting of water samples collected from ponds, lakes, rivers, and drains in Bangladesh. The survival of S. dysenteriae in microcosms was assessed by viable counting on MacConkey agar. After 2 to 3 weeks, S. dysenteriae 1 became nonculturable but remained viable. After 6 weeks, this nonculturable but viable S. dysenteriae 1 was detected by both the polymerase chain reaction and the fluorescent-antibody methods. The viable but nonculturable state of S. dysenteriae 1 demonstrated in this study may be important for understanding the epidemiology of shigellosis.