Application of PFGE to source tracking of faecal pollution in coastal recreation area: a case study in Aoshima Beach, Japan

Abstract

Aims: The development of a microbial source tracking (MST) method is strongly desired to ensure public health and bacteriological safety in coastal recreation areas. We try to specify the source of faecal pollution by applying pulsed‐field gel electrophoresis (PFGE) to the study of the aquatic environment on Aoshima Beach, Japan. Methods and Results: Enterococcus faecium, an enterococcus, was used as a faecal indicator bacterium in this study. Enterococcus faecium strains were isolated and identified from each water sample collected from Aoshima Beach and five rivers (Oyodo, Kiyotake, Kaeda, Chifuku and Tsukunami Rivers) that might be potential sources of faecal pollution. Enterococcus faecium strains collected from water samples were analysed using PFGE. The similarities of all the PFGE types of the Ent. faecium strains were compared using dendrogram analysis. The PFGE types of the strains isolated from Aoshima Beach showed a high similarity to those of the strains isolated from the Oyodo River at a 0·9 similarity level. It was suggested that the Oyodo River is the source of faecal pollution on Aoshima Beach. Conclusions: The PFGE analysis using enterococci is a potential tool for the MST of faecal indicator bacteria that can be applied to the study of the coastal environment. Significance and Impact of the Study: This is one of the studies that PFGE was applied to the coastal environment. The approach using PFGE could estimate the river that is source of faecal pollution in Aoshima Beach. By applying PFGE as a tool of MST method, detailed information of faecal pollution in coastal area can be provided.

Distributions of Salmonella Subtypes Differ between Two U.S. Produce-Growing Regions

“…While subtyping can yield information on likely potential hosts of Salmonella, studies (18)(19)(20)(21)(22) have also demonstrated the application of subtyping to track specific food-borne pathogen subtypes in the environment. One study (22) investigating the source of fecal pollution on a Japanese beach showed a strong association between Enterococcus faecium isolated in samples from the beach and one of the suspected contamination sources (a river that drains into the beach) by PFGE typing.…”

“…One study (22) investigating the source of fecal pollution on a Japanese beach showed a strong association between Enterococcus faecium isolated in samples from the beach and one of the suspected contamination sources (a river that drains into the beach) by PFGE typing. Cooley et al (18) used PFGE typing to track Escherichia coli O157:H7 in a California produce-growing region and found that the same PFGE type of E. coli O157:H7 was isolated from feral swine, cattle, surface water, sediment, and soil from one of the spinach farms that had been implicated in the 2006 spinach-borne E. coli O157:H7 outbreak.…”

Antibiotic Resistance Profiling and Genotyping of Vancomycin-Resistant Enterococci Collected from an Urban River Basin in the Provincial City of Miyazaki, Japan

“…The enterococci counts tended to decrease at St.2 and St.3 rather than St.1, suggesting that the number of enterococci were decreased by the dilution effect of river water due to the inflow of seawater and a lot of tributaries, or influence of salt. In the Miyazaki city study area, E. faecalis and E. faecium were previously detected in river, estuarine, and coastal areas [29], suggesting that enterococci are ubiquitously present in the water environments of Miyazaki, a provincial seaside city. This study confirmed these findings.…”

Assessing host-specificity of Escherichia coli using a supervised learning logic-regression-based analysis of single nucleotide polymorphisms in intergenic regions

“…Given that such Table 4 Logic regression analysis of E. coli samples classified according to host animal of origin and evaluation of logic models using fivefold cross validation and permutation testing. cluster-based statistical methods that are commonly used in 555 microbial systematics (White et al, 2011;Furukawa et al, 2011;556 Carson et al, 2001;Ruecker et al, 2012) Alternatively, this small population may, in fact, be truly 573 host-specific to deer, but for which the intergenic sequences used 574 in our analysis may be insufficient in resolving this association. The interactive iTOL online tool was used for tree editing to overlay animal host grouping information onto the tree.…”