Time trends in the prevalence of Escherichia coli and enterococci in bivalves harvested in Norway during 2007–2012

Lunestad, Bjørn Tore; Frantzen, Sylvia; Svanevik, Cecilie Smith; Roiha, Irja Sunde; Duinker, Arne

doi:10.1016/j.foodcont.2015.08.001

Cited by 16 publications

(10 citation statements)

References 28 publications

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“…Maximum E. coli concentrations in mussels and seawater were regularly recorded at all stations in the summer, and minimum concentrations were recorded in the winter. This fi nding is in agreement with the results of previous environmental studies showing that bacterial cell numbers typically increase during the summer and when the temperature rises [31,18,9,30,22]. At the same concentration of E. coli in seawater, mussels concentrated more E. coli during winter than during the summer period, that is at lower temperature [31].…”

Section: Discussion / Raspravasupporting

confidence: 92%

“…During heavy rainfall or surcharge of sewage waters there is an overfl ow to the city port. According to research in Norway [22] one additional complicating factor is precipitation in the form of snow, which will only bring land borne faecal material into the sea after thawing. Similar results of low heterotrophic bacterial counts were recorded previously in the river Ombla estuary [3] and in the bay of Gruž [38].…”

Section: Discussion / Raspravamentioning

confidence: 99%

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Microbiological Quality of Seawater and Mussels (Mytilus galloprovincialis, Lamarck 1819) in the Dubrovnik Coastal Area (Southeastern Adriatic)

et al. 2021

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This research was conducted between March 2016 and March 2017 as the first study on the water and mussel quality in the coastal area of Dubrovnik (Croatia). Bacteriological analyses were conducted simultaneously on wild mussels (Mytilus galloprovincialis) tissue and their ambient water. The total numbers of heterotrophic bacteria, total coliforms, faecal coliforms and faecal streptococci in the water were determined. Concentrations of Escherichia coli were measured in mussel. The investigated stations are located in coastal water, which is particularly influenced by climatic and anthropogenic factors interacting at the boundaries between the land and freshwater and seawater environments. Seasonal variables, such as rainfall and riverine network characteristics, determine the delivery of bacteria (including E.coli) to coastal water. Direct methods of assessing the density of heterotrophic bacteria at all sampling stations showed the characteristics of an oligotrophic area. The abundance of faecal coliform bacteria was in all cases higher within mussel tissue than in the surrounding water where levels were sometimes undetectable. Maximum E. coli concentrations in mussels and seawater were regularly recorded through the summer, with the exceptions of April 2016 and January 2017 at two stations following precipitation. Minimum faecal coliform concentrations were recorded in the winter.

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Section: Discussion / Raspravasupporting

confidence: 92%

Section: Discussion / Raspravamentioning

confidence: 99%

Microbiological Quality of Seawater and Mussels (Mytilus galloprovincialis, Lamarck 1819) in the Dubrovnik Coastal Area (Southeastern Adriatic)

et al. 2021

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“…Several studies have investigated the factors that can alter E. coli concentrations in seawater. Rainfall is recognizably one of the main factors (Lunestad et al, 2016) affecting the increased exposure of bacterial pathogens in bivalves (Campos et al, 2011). During rainfall, the water washes animal wastes (containing E. coli) from contaminated areas and finds its way into water bodies.…”

Section: Survival Of E Coli In the Marine Environmentmentioning

confidence: 99%

Isolation and characterisation of Shiga toxin-producing Escherichia coli from Norwegian bivalves

et al. 2019

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P a g e | 1 P a g e | 2 ABSTRACT Only few studies concerning Shiga toxin-producing E. coli (STEC) detection in coastal environments and bivalves have been reported and there have been no reported outbreaks by STEC from bivalves in the world.The aim of this thesis was to investigate the occurrence of STEC in Norwegian bivalves, and to characterize potential STEC isolates obtained from the samples.To improve our understanding of STEC, the occurrence was investigated in 269 bivalves collected from harvesting areas along the Norwegian coast in 2016/17. Microbial enrichment of the samples followed by DNA extraction with subsequent screening of STEC-associated genes was performed as described in ISO/TS -13136. Real-time PCR assays were conducted for genes encoding Shiga toxin (stx1 and stx2), intimin (eae) and the five major serogroups of concern (O157, O26, O111, O145 and O103). The screening results revealed the presence of the virulence genes (eae and stx) in 19 of the 269 samples. These 19 samples were selected for isolation of STEC. Colonies obtained from enrichment were screened for presence of stx and positive isolates were further characterized to determine their serotype and virulence profile. For two samples, automated immuno-magnetic separation (AIMS) was performed to facilitate isolation of STEC associated serogroups.Presumptive positive colonies from different serogroups were isolated by AIMS and the serogroup O157 was confirmed by real-time PCR but lacked the virulence genes. A total of three samples from 269 analyzed harbored STEC isolates, therefore, there seems to be a low risk of human infection by STEC in Norwegian bivalves.

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“…These findings are supported by the study from Scopel et al which found that, on average, the accumulation of E. coli in seawater increased up to 2 log colony forming unit (CFU) with the observed highest concentration at 4500 CFU/100 mL after precipitation at a beach [25]. A positive correlation between the impact of precipitation and concentrations of E. coli was also observed among blue mussels [26]. This study suggests that precipitation can introduce microbial contaminants to coastal areas and other locations of oyster cultivation.…”

Section: Discussionmentioning

confidence: 57%

Modelling of Indicator Escherichia coli Contamination in Sentinel Oysters and Estuarine Water

Jeamsripong

Atwill

2019

IJERPH

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This study was performed to improve the ability to predict the concentrations of Escherichia coli in oyster meat and estuarine waters by using environmental parameters, and microbiological and heavy metal contamination from shellfish growing area in southern Thailand. Oyster meat (n = 144) and estuarine waters (n = 96) were tested for microbiological and heavy metal contamination from March 2016 to February 2017. Prevalence and mean concentrations of E. coli were 93.1% and 4.6 × 103 most probable number (MPN)/g in oyster meat, and 78.1% and 2.2 × 102 MPN/100 mL in estuarine water. Average 7-day precipitation, ambient air temperature, and the presence of Salmonella were associated with the concentrations of E. coli in oyster meat (p < 0.05). Raw data (MPN/g of oyster meat and MPN/100 mL of estuarine water) and log-transformed data (logMPN/g of oyster meat and logMPN/100 mL of estuarine water) of E. coli concentrations were examined within two contrasting regression models. However, the more valid predictions were conducted using non-log transformed values. These findings indicate that non-log transformed data can be used for building more accurate statistical models in microbiological food safety, and that significant environmental parameters can be used as a part of a rapid warning system to predict levels of E. coli before harvesting oysters.

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Time trends in the prevalence of Escherichia coli and enterococci in bivalves harvested in Norway during 2007–2012

Cited by 16 publications

References 28 publications

Microbiological Quality of Seawater and Mussels (Mytilus galloprovincialis, Lamarck 1819) in the Dubrovnik Coastal Area (Southeastern Adriatic)

Microbiological Quality of Seawater and Mussels (Mytilus galloprovincialis, Lamarck 1819) in the Dubrovnik Coastal Area (Southeastern Adriatic)

Isolation and characterisation of Shiga toxin-producing Escherichia coli from Norwegian bivalves

Modelling of Indicator Escherichia coli Contamination in Sentinel Oysters and Estuarine Water

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