Levels of Indicator Bacteria and Characteristics of Foodborne Pathogens from Carcasses of Cattle Slaughterhouses in Korea

The initial microbial contamination of carcasses during slaughtering adversely affects spoilage and shelf life and is of global concern for food safety and meat quality. This study evaluated the hygiene and quality using the prevalence of foodborne pathogens and the level of indicator bacteria on 200 carcasses, collecting 10 from each of 20 cattle slaughterhouses in Korea. The distribution of aerobic bacterial count in carcasses was significantly highest at 2.0-3.0 log10 CFU/cm2 (34.1%), whereas the Escherichia coli count was significantly highest at under 1.0 log10 CFU/cm2 (94.0%) (P < 0.05). Clostridium perfringens was most prevalent (60.0% of slaughterhouses; 17.5% of carcasses), followed by Yersinia enterocolitica (30.0% of slaughterhouses; 6.5% of carcasses), Staphylococcus aureus (15.0% of slaughterhouses; 4.0% of carcasses), Listeria monocytogenes 1/2a (5.0% of slaughterhouses; 1.0% of carcasses), Salmonella enterica subsp. enterica serovar Infantis (5.0% of slaughterhouses; 1.0% of carcasses), and Shiga toxin-producing E. coli O:66 (5.0% of slaughterhouses; 0.5% of carcasses). Although 28 C. perfringens isolates from 11 slaughterhouses were divided into 21 pulsotypes, all isolates showed the same toxinotype as type A and only carried the cpa. Interestingly, 83.3% of isolates from two slaughterhouses located in the same province showed resistance to tetracycline. Furthermore, 13 Y. enterocolitica isolates from six slaughterhouses were divided into seven pulsotypes that were divided into biotypes 1A and 2 and serotypes O:5 and O:8, except for isolates that could not be typed. Twelve (92.3%) isolates only carried ystB, but one (7.7%) isolate carried ail and ystA. Moreover, 46.2% of Y. enterocolitica isolates showed multidrug resistance against ampicillin, cefoxitin, and amoxicillin/clavulanic acid. This study supports the need for continuous monitoring of slaughterhouses and hygiene management to improve the microbiological safety of carcasses.

Assessment of the content of macronutrients and microbiological safety of dry dog foods

In Europe, there are no legal regulations specifying maximum allowable limits for pathogenic bacteria or fungi and yeasts in dog food. For proximate composition, the European Pet Food Industry Federation (FEDIAF) nutritional guidelines provide minimum recommended levels for protein and fat only, not for other ingredients and no safe maximum levels. Therefore, the aim of this study was to evaluate the microbiological safety of 35 dry dog foods, taking into account the division into foods with grains as the main plant ingredient and those described as grain-free. We assumed that grain-included foods are more susceptible to the presence of the total number of aerobic bacteria. This parameter is an essential, hygienic criterion informing about the microbiological safety of the pet food. It also inform about the microbiological quality of the food ingredients used, the effectiveness of decontamination during the production process, sanitary and hygienic conditions during the acquisition, processing and marketing of pet food and its components. In the case of macronutrients, the results in some cases were multiples of the minimum recommended levels. The most important microorganisms that presence was found in the analyzed dog foods were indicator bacteria (E. coli and coliform bacteria, Clostridium perfringens), whose presence in feed constitutes microbiological contamination. They inform about sanitary and hygienic conditions during the production and storage of the pet food. The current guidelines recommend microbiological testing of food for the presence of Salmonella bacilli as the basic indicator for assessing the sanitary quality. No Salmonella spp. was detected in any of the foods. The remaining analyzed bacteria (Proteus spp., Enterococcus spp., Staphylococcus spp.) as well as molds and yeasts, were present in both grain-included and grain-free foods. The obtained results showed that in terms of microbiological safety, grain-included foods come out worse, because microorganisms were detected more frequently in this type of dry dog food.

Tracking spatio-temporal distribution and transmission of antibiotic resistance in aquatic environments by using ESBL-producing Escherichia coli as an indicator

Wastewater treatment plants (WWTPs) play an important role in the production, and transmission of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) as a convergence for human, animal, and environmental wastewater. The aim of this study was to investigate the spatio-temporal variation and influencing factors of ARB in different functional areas of the urban WWTP and the connecting rivers for 1-year monitoring using extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) as an indicator bacteria, and to study the transmission patterns of ARB in the aquatic environment. The results showed that ESBL-Ec isolates were identified from the WWTP (n = 219), including influent (n = 53), anaerobiotic tank (n = 40), aerobiotic tank (n = 36), activated sludge tank (n = 31), sludge thickner tank (n = 30), effluent (n = 16), and mudcake storage area (n = 13). The dehydration process can significantly remove the ESBL-Ec isolates; however, ESBL-Ec was still detected in samples collected from the effluent of the WWTP (37.0%). The detection rate of ESBL-Ec was significantly different across seasons (P < 0.05), and ambient temperature was negatively correlated with the detection rate of ESBL-Ec (P < 0.05). Furthermore, a high prevalence of ESBL-Ec isolates (29/187, 15.5%) was detected in samples collected from the river system. These findings emphasize that the high majority of ESBL-Ec in aquatic environments is alarming because it poses a significant threat to public health. Clonal transmission of ESBL-Ec isolates between the WWTP and rivers based on the spatio-temporal scale was observed by pulsed-field gel electrophoresis analysis, ST38 and ST69 ESBL-Ec clone were selected as prioritized isolates for antibiotic resistance monitoring in the aquatic environment. Further phylogenetic analysis showed human-associated (feces, blood) E. coli was the main source contributing to the presence of antibiotic resistance in aquatic environments. Longitudinal and targeted monitoring of ESBL-Ec in WWTPs and the development of effective wastewater disinfection strategies before effluent discharge from WWTPs are urgently required, to prevent and control the spread of antibiotic resistance in the environment.

Assessment of ATP-Bioluminescence and Dipslide Sampling to Determine the Efficacy of Slaughterhouse Cleaning and Disinfection Compared with Total Aerobic and Enterobacterales Counts

Inadequate cleaning and disinfection (C&D) in slaughterhouses can cause bacterial contamination of meat, resulting in foodborne disease and reduced meat quality. Different methods for monitoring the efficacy of C&D procedures are available, but few studies have assessed their reliability. This study examined C&D efficacy in slaughterhouses and evaluated the diagnostic performance of methods for measuring surface hygiene. One red meat and one poultry slaughterhouse in Sweden were each visited on six occasions before and six occasions after C&D. Sampling points were sampled with: swabbing and plating for total aerobic bacteria (TAB) and Enterobacterales (EB); dipslides for total viable count; and ATP-bioluminescence tests. To evaluate the diagnostic performance of the dipslide and ATP-bioluminescence methods, the results were compared with (TAB) as a reference. In total, 626 samples were collected. For the majority of samples, TAB was lower after than before C&D and EB were mainly detected before C&D, indicating C&D efficacy. Greater reductions in mean TAB were observed in processing areas (2.2 and 2.8 log CFU/100 cm2 in red meat and poultry slaughterhouse, respectively) than in slaughter areas (1.3 log CFU/100 cm2 in both slaughterhouses). Approximately half of all samples were assessed as non acceptably clean (52% for red meat and 46% for poultry slaughterhouse) according to previously published thresholds. Critical food contact surfaces that were insufficiently cleaned and disinfected were plucking fingers, shackles, and a post-dehairing table. Cleaning and disinfection of drains and floors were inadequate. The ATP-bioluminescence method showed low specificity compared with the reference (TAB) in both the red meat (0.30) and poultry slaughterhouses (0.64). The sensitivity of dipslides was low (0.26) in the red meat slaughterhouse compared with TAB. A combination of ATP-bioluminescence and dipslides could provide more accurate estimates of C&D efficacy.

Microbial indicators in municipal solid waste compost and their fate after land application of compost

Despite the extensive agricultural use of municipal solid waste (MSW) compost, there is little information about microbial characteristics of the MSW compost and fate of microorganisms following land application. This study was designed to determine the microbial quality and germination index (GI) of the MSW compost as well as fate of indicator microorganisms after application of MSW compost. The results showed a high fraction of samples are immature (GI < 80). In 27% and 16% of samples fecal coliforms and Salmonella were detected in a range exceeding the recommended value for unrestricted application of compost, respectively. HAdV was also detected in 62% of samples. Fecal enterococci were detected with relatively high concentrations in all samples and showed higher survival rate than other indicators in land-applied MSW compost. The results showed that climate condition significantly contributed to the decline of indicator bacteria in land-applied compost. The results highlight the need for further quality monitoring of compost to ensure that its application does not lead to environmental or human health problems. Furthermore, because of the high concentrations and high survival rate of enterococci in compost samples, they can be specifically proposed as an indicator microorganism for MSW compost quality monitoring.

The hidden diversity of microbes in ballast water and sediments revealed by metagenomic sequencing

With the rapid globalization of trade, the worldwide spread of pathogens through ballast water is becoming a major concern. Although the international maritime organization (IMO) convention has been adopted to prevent the spread of harmful pathogens, the limited species resolution of the current microbe-monitoring methods challenged the ballast water and sediments management (BWSM). In this study, we explored metagenomic sequencing to investigate the species composition of microbial communities in four international vessels for BWSM. Our results showed the largest species diversity (14,403) in ballast water and sediments, including bacteria (11,710), eukaryotes (1007), archaea (829), and viruses (790). A total of 129 phyla were detected, among which the Proteobacteria, followed by Bacteroidetes, and Actinobacteria were the most abundant. Notably, 422 pathogens that are potentially harmful to marine environments and aquaculture were identified. The co-occurrence network analysis showed that most of these pathogens were positively correlated with the commonly used indicator bacteria Vibrio cholerae, Escherichia coli, and intestinal Enterococci species, validating the D-2 standard in BWSM. The functional profile showed prominent pathways of methane and sulfur metabolism, indicating that the microbial community in the severe tank environment still utilizes the energy to sustain such a high level of microbe diversity. In conclusion, metagenomic sequencing provides novel information for BWSM.

Repeated hydrogen peroxide dosing briefly reduces cyanobacterial blooms and microcystin while increasing fecal bacteria indicators in a eutrophic pond

This study explored the effects of H₂O₂ on Cyanobacteria and non-target microbes using fluorometry, microscopy, flow cytometry, and high throughput DNA sequencing of the 16S rRNA gene during a series of mesocosm and whole-ecosystem experiments in a eutrophic pond in NY, USA. The addition of H₂O₂ (8 mg/L) significantly reduced Cyanobacteria concentrations during a majority of experiments (66%; 6 of 9) and significantly increased eukaryotic green and unicellular brown algae in 78% and 45% of experiments, respectively. While heterotrophic bacteria declined significantly following H₂O₂ addition in all experiments, bacteria indicative of potential fecal contamination (Escherichia coli, Enterococcus, fecal coliform bacteria) consistently and significantly increased in response to H₂O₂, evidencing a form of 'pollution swapping'. H₂O₂ more effectively reduced Cyanobacteria in enclosed mesocosms compared to whole-ecosystem applications. Ten whole-pond H₂O₂ applications over a two-year period temporarily reduced cyanobacterial levels but never reduced concentrations below bloom thresholds and populations always rebounded in two weeks or less. The bacterial phyla of Cyanobacteria, Actinobacteria, and Planctomycetes were the most negatively impacted by H₂O₂. Microcystis was always reduced by H₂O₂, as was the toxin microcystin, but Microcystis remained dominant even after repeated H₂O₂ treatments. Although H₂O₂ favored the growth of eukaryotic algae over potentially harmful Cyanobacteria, the inability of H₂O₂ to end cyanobacterial blooms in this eutrophic waterbody suggests it is a non-ideal mitigation approach in high biomass ecosystems and should be used judiciously due to potential negative impacts on non-target organisms and promotion of bacteria indicative of fecal contamination.

Assessment on impact of sewage in coastal pollution and distribution of fecal pathogenic bacteria with reference to antibiotic resistance in the coastal area of Cape Comorin, India

Sewage is one of the biggest contributors to coastal pollution. The study was aimed to assess the impact of sewage on coastal water quality of Kanyakumari, the southernmost part of India. A bacteriological survey was made on distribution and abundance of fecal indicators and human pathogenic bacteria and seasonal influence on the bacterial load and antibiotic resistance of the isolates. Samples were collected from sewage discharge point along the eastern shore of Kanyakumari Coast from February 2019 to January 2020. Nine pollution indicator bacteria and pathogenic species such as Escherichia coli, Klebsiella spp., Enterococcus faecalis, Aeromonas spp., Proteus mirabilis, Salmonella typhi, Vibrio cholerae, Shigella spp. and Flavobacterium spp. were isolated from the samples. These isolates were tested against 10 antibiotics, using Kirby Bauer method. All the isolates were resistant to at least two antibiotics. The presence of antibiotic resistant bacteria has been used as bio-indicators of pollution. Hence it is clear that the domestic sewage entering the coast is untreated which might lead a serious impact on human and marine wildlife along coastlines.

Comparative stability of assay results of enterococci measured by culture and qPCR over time in bathing beach waters

The diurnal presence of the culturable bacterial indicators of fecal contamination in the water environment has been shown to be highly variable over time due to natural die-off and injury from effects of sunlight and other environmental stressors. Molecular analytes of a quantitative polymerase chain reaction (qPCR) method for measuring fecal contamination degrade considerably slower than the alternative of culturable fecal indicator bacteria. The rapid qPCR method holds the promise of more timely notification decisions with respect to postings or closure being made on the basis of microbial water quality samples collected earlier on the same day. In the case of culture-based methods requiring a 24 h or longer incubation period, decisions must be based on samples collected no sooner than the previous day. To examine the effect of this lag in assay results, temporal stability of a molecular Enterococci target analyte with that of traditional culture-based cells is compared using data from USEPA studies conducted between 2003 and 2007 on seven freshwater and marine beaches that were impacted by publicly-owned treatment works. Generally, levels of the molecular indicator were more consistent throughout the day between 8:00 am and 3:00 pm. The difference in temporal consistency is even more pronounced when the 24-h lag in culture-based results is taken into account.

Spatial and temporal variations of faecal indicator bacteria in Lake Bunyonyi, South-Western Uganda

Background Microbial water quality serves to indicate health risks associated with the consumption of contaminated water. Nevertheless, little is known about the microbiological characteristics of water in Lake Bunyonyi. This study was therefore undertaken to examine the spatial and temporal variations of faecal indicator bacteria (FIB) in relation to physicochemical parameters in Lake Bunyonyi. Result The FIB concentration was consistently measured during sampling months and correlated with each other showing the presumed human faecal pollution in the lake. The highest concentration values for E. coli (64.7 ± 47.3 CFU/100 mL) and enterococci (24.6 ± 32.4 CFU/100 mL were obtained in the station close to the Mugyera trading centre. On a temporal basis, the maximum values were recorded during the rainy season in October 2019 (70.7 ± 56.5 CFU/100 mL for E. coli and 38.44 ± 31.8 CFU/100 mL for enterococci. FIB did not differ significantly among the study stations (p > 0.05) but showed significant temporal variations among the months (p < 0.05) with concentrations being significantly high in wet season than dry season (U = 794, p < 0.0001 for E. coli; U = 993.5, p = 0.008 for enterococci). Spearman’s rank correlation revealed that FIB concentrations were significantly positively correlated with turbidity and DO concentration levels (p < 0.05). Approximately 97.2% of the water samples had E. coli and enterococci concentrations levels below USEPA threshold for recreational waters. Likewise, 98.1 and 90.7% of samples recorded E. coli and enterococci counts exceeding the UNBS, APHA, WHO and EU threshold values for drinking water. Conclusion The FIB counts show that the Lake Bunyonyi water is bacteriologically unsuitable for drinking unless it is treated since the FIB pose health risks to consumers. Besides, the water can be used for recreational purposes.

Influence of anthropogenic activities on the spatial distribution of heterotrophic, indicator and pathogenic bacteria around Andaman and Nicobar Islands

To examine the influence of anthropogenic activities on the marine ecosystem around the Andaman and Nicobar Islands, a study was conducted to investigate the abundance of heterotrophic, indicator and pathogenic bacteria during the monsoon season. We noticed the higher abundance of heterotrophic, indicator (Escherichia coli and Enterococcus faecalis) and pathogenic bacterial counts (Aeromonas hydrophila, Enterobacter aerogens, Escherichia coli strain O157:H7, Shigella dysenteriae and Vibrio parahaemolyticus) near the 10^o channel, which is the principal route to reach Andaman mainland. Most of the stations are offshore (chosen to cover shipping tracks) at a distance ranging from 41 to 266 km from the coast. The nearest station to the coast was at 21 km away. Apart from those mentioned above, several other pathogenic bacteria were also detected such as Klebsiella pneumoniae, Salmonella paratyphi, Vibrio cholera and Vibrio vulnificus but they are sparsely detected at few stations only.

Interaction of bacterial communities and indicators of water quality in shoreline sand, sediment, and water of Lake Michigan

Shoreline sand harbors high concentrations of fecal indicator bacteria (FIB) that may be resuspended into the water column through washing and resuspension. Studies have explored coastal processes that influence this sand-water flux for FIB, but little is known about how microbial markers of contamination or the bacterial community interact in the sand-water interface. In this study, we take a three-tiered approach to explore the relationship between bacteria in sand, sediment, and overlying water at three shoreline sites and two associated rivers along an extended freshwater shoreline. Samples were collected over two years and analyzed for FIB, two microbial source tracking (MST) markers (Catellicoccus marimammalium, Gull2; Bacteroides HF183), and targeted metagenomic 16S rRNA gene analysis. FIB was much higher in sand than in water at all three sites. Gull2 marker was abundant in shoreline sand and water while HF183 marker was mostly present in rivers. Overall bacterial communities were dissimilar between sand/sediment and water, indicating little interaction. Sediment composition was generally unfavorable to bacterial resuspension. Results show that FIB and MST markers were effective estimates of short-term conditions at these locations, and bacterial communities in sand and sediment reflected longer-term conditions. Findings are useful for locating contamination sources and targeting restoration by evaluating scope of shoreline degradation.

The composition of cultivable bacteria, bacterial pollution, and environmental variables of the coastal areas: an example from the Southeastern Black Sea, Turkey

The composition and metabolic properties of cultivable heterotrophic aerobic bacteria, the levels of indicator bacteria, and physicochemical parameters were investigated in the seawater samples collected from 20 stations in coastal areas of the eastern part of the Black Sea, Turkey, between May 2017 and February 2018. The levels of indicator bacteria were detected above the national limit values during the study period. Thirty-five different bacterium species were identified. Enterobacteriaceae was recorded as the most dominant family (34.2%), and Gammaproteobacteria was recorded as the most dominant class (74.2%). Bacteriological threats on human and ecosystem health were determined in coastal areas of the Southeastern Black Sea. The determination of the high levels of indicator bacteria, the high ratio of fecal coliform/fecal streptococci (FC/FS ratio), and pathogenic bacteria regarding human and ecosystem health showed that these coastal areas under the influences of terrestrial and human-sourced bacteriological pollution. This study has contributed to the increase of knowledge of understanding the protection and rehabilitation ways of the Black Sea coastal regions against land-based pollution sources considering the interdependent structure of all Black Sea countries. Coastal areas are accepted as the most fragile part of the marine environments and our findings showed the potential bacteriological risks in coastal areas of the Southeastern Black Sea as an important example. Serious precautions should be taken for the protection in this area and such coastal ecosystems to prevent hazardous problems.

Species-specific effects of arsenic on the soil collembolan gut microbiota

It is well established that arsenic (As) pollution has a severe threat to food security and soil non-target organisms, however, its influences on soil fauna gut microbiota are poorly understood. The gut microbiota of soil fauna play an important role in host health and nutrient cycling. Here, we used dietary exposure to investigate the effects of As on the mortality and gut microbiota of two model soil collembolans (Folsomia candida and Onychiurus yodai) and determine the accumulation of As in collembolan body tissues. The results showed that, although As exposure did not induce the mortality of the two species, dose dependence of As accumulation was indeed detected in their body tissues. Oral As exposure (500 μg g^-1 yeast) significantly altered the community structure (P < 0.05) of F. candida gut microbiota and reduced its diversity (by more than 20%; P < 0.05) compared to the control; however, no significant effects were observed in O. yodai gut microbiota. The two collembolan species possess significantly different gut microbiota (P < 0.05), which may partly explain the differences of the two collembolan gut microbiota response to As exposure. We further found that the genera Ochrobactrum, Geobacter and Staphylococcus were sensitive to As exposure in F. candida (P < 0.05), but these bacteria were low abundance and not altered in O. yodai. Moreover, the relative abundance of these bacteria was significantly correlated with As bioaccumulation in F. candida body tissues (P < 0.05, R² > 0.6). Higher As bioaccumulation factor was also found in O. yodai body tissues compared to the F. candida. These results indicate that collembolan gut microbiota present a species-specific response to As and may be a more sensitive indicator than the mortality of collembolan.

Diversity and antibiotic resistance among Escherichia coli populations in hospital and community wastewater compared to wastewater at the receiving urban treatment plant

Bacterial diversity and antimicrobial resistance patterns among the indicator organism Escherichia coli were monitored in wastewater samples collected over one year from a hospital (HW), a community (CW) and the receiving urban (UW) wastewater treatment plant (WWTP). We compared levels of antibiotic resistance in the different types of wastewater, and identified whether resistant strains were endemic in the wastewater system. If so, implementation of local treatment at certain resistance hotspots (e.g. hospital outlets) could be used to decrease the amount of resistant bacteria in the wastewater. E. coli from HW (n = 2644), CW (n = 2525) and UW (n = 2693) were analyzed by biochemical phenotyping (PhenePlate System) and antimicrobial susceptibility testing to nine antibiotics (AREB System). The phenotypic diversities of the total E. coli populations were similar for all three sites (Simpson's Diversity index, Di = 0.973), however for individual samples, HW showed low diversities (Median Di = 0.800) and the E. coli flora was often dominated by strains that may have originated from the fecal flora of single individuals. The diversities in CW samples was higher (Median Di = 0.936), and UW samples showed similar diversities as the whole collection of isolates (Median Di = 0.971). Resistance to at least one of the nine antibiotics was observed in 45% of the HW isolates, 44% of CW isolates, and 33% of UW isolates. Resistance to gentamicin and chloramphenicol was uncommon (3.2 and 5.3%, respectively), whereas resistance to tetracycline and ampicillin was most common (24% and 31%, respectively). Extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) were more common in HW (11.5%) and in CW (6.9%) compared to UW (3.7%). A high diversity (Di = 0.974) was observed among ESBL-EC isolates from UW (n = 99), indicating absence of any clonal structure among these isolates. Common PhP types of ESBL-EC often dominated in each HW sample, but were not identified across different samples, whereas ESBL-EC in CW showed low diversity (Di = 0.857) and were dominated by a specific PhP type that was found across almost all CW samples. The antibiotic resistance rates were highest in hospital wastewater, but surprisingly they were also high in the studied community wastewater, compared to the urban wastewater. The relative contribution of HW seemed low in terms of dissemination of antibiotic resistant bacteria to the WWTP.

Differences in antimicrobial resistance of commensal Escherichia coli isolated from caecal contents of organically and conventionally raised broilers in Austria, 2010-2014 and 2016

The prevalence of antimicrobial resistance in commensal Escherichia coli isolated from organically raised broiler flocks was compared to the prevalence in isolates from conventional flocks. From 2010 to 2014, and in 2016, resistance trends and multidrug resistance in isolates from the caecal contents of flocks from both broiler production forms were analyzed. Samples were taken in four abattoirs accounting for at least 90% of the national slaughtered broiler population. In total, 962 commensal E. coli were obtained from organically raised broiler flocks (n = 142) and from conventionally raised broiler flocks (n = 820). The mean prevalence of commensal E. coli isolates, which were fully susceptible to the antimicrobials tested, was 43.3% in organically raised broiler flocks and thus significantly higher (P < 0.001) compared to 16.7% in conventionally operated flocks. During the study period, the proportion of fully susceptible isolates increased significantly in both broiler populations. Antimicrobial resistance rates were significantly lower in commensal E. coli isolated from organic compared to conventional production regarding ciprofloxacin (33.3% versus 69.1%), nalidixic acid (33.7% versus 67.4%), sulfamethoxazole (26.7% versus 39.9%), ampicillin (19.0% versus 33.8%) and trimethoprim (12.8% versus 24.9%). Regarding tetracycline, tigecycline and ceftazidime resistance rates were slightly but not significantly higher in isolates from organic flocks (27.6% versus 25.9%; 4.0% versus 1.4%; 2.0% versus 1.9%). This fact is surprising for tetracycline, as none of the investigated organic flocks had been treated with this antimicrobial during their lifetime. No resistances were found in isolates from both production forms against colistin and meropenem, and from organic flocks against azithromycin. The annual prevalence of resistance against ciprofloxacin and nalidixic acid decreased significantly in isolates from both broiler production forms. In isolates from organic flocks, it also decreased regarding ampicillin and sulfamethoxazole. Significant increasing trends were observed in the resistance prevalence against trimethoprim and borderline significantly for ampicillin in commensal E. coli from conventional flocks. Multidrug resistance was detected at a significantly higher prevalence in isolates from conventionally raised flocks (35.1%) compared to organic flocks (22.7%). Findings from this study clearly indicate the influences of organic compared to conventional broiler production practices on the prevalence of antimicrobial resistance in commensal E. coli from broiler flocks.

Bacteriological quality, heavy metal and antibiotic resistance in Sapanca Lake, Turkey

Sapanca Lake is important as a source of drinking water. In this study, we aimed to detect the bacterial quality, the frequency of bacterial antibiotic and heavy metal resistance, and bioindicator bacteria in the water samples taken from Sapanca Lake in the period between 2008 and 2010. The resistance of bacterial isolates to certain antibiotics and heavy metal salts was investigated using disc diffusion and minimum inhibitory concentration techniques. Bacterial metabolic reactions were tested using the VITEK 2 Compact 30 micro identification system for identification of cultivable bacteria. Twenty-seven bacteria species belonging to three classes-Gammaproteobacteria, Bacilli, Flavobacteria-were recorded for the first time in Sapanca Lake. The highest indicator bacteria were recorded as 71 ± 3.1 × 10⁴ CFU/100 ml in the summer season. The highest bacterial resistance was recorded as 90.47% against vancomycin in a total of 84 strains. Ampicillin (88.10%) and amoxicillin-clavulanate (64.29%) followed them. The resistance varied between 10.71 and 59.52% against cefuroxime, kanamycin, aztreonam, ceftazidime, cefotaxime, and oxacillin. The highest frequency against heavy metal salts was recorded as 74.19% against NiCl₂. The heavy metal resistance against Cu, Zn, Hg, and Cd detected as 52.38%, 46.42%, 33.33%, and 26.19%, respectively. The results showed that the occurrence of heavy metals and antibiotic sources in Sapanca Lake induced a tolerance in bacteria for the metal salts and antibiotic derivatives tested. The fluctuations in the indicator bacteria and the occurrence of pathogenic bacteria also showed the possibility that the coastal areas of Sapanca Lake had been exposed to contamination due to inadequate sewage treatment.

Intraseasonal variation of E. coli and environmental covariates in two irrigation ponds in Maryland, USA

The microbial quality of irrigation water is typically assessed by measuring the concentrations of E. coli in irrigation water reservoirs that are variable in space and time. E. coli concentrations are affected by water quality parameters that co-vary with E. coli concentrations and may be easily measured with currently available sensors. The objective of this work was to identify the most influential environmental covariates affecting E. coli concentrations during a three-month biweekly monitoring period within two irrigation ponds in Maryland during the summer of 2017. E. coli levels as well as sensor-based water quality parameters including turbidity, pH, dissolved oxygen, dissolved fluorescent organic matter, conductivity, and chlorophyll were measured at 23 and 34 locations in ponds 1 and 2, respectively. Regression tree analyses were used to determine the most influential water quality parameters for the prediction of E. coli levels. Correlations between E. coli and water quality covariates were not strong and were inconsistently significant. Shoreline sample locations had higher E. coli concentrations than interior pond samples and significant differences were observed when comparing these two groups. Regression trees provided fairly accurate predictions of E. coli levels based on water quality parameters with R² values ranging from 0.70 to 0.93. Factors identified via the regression trees varied by sampling date but common leading covariates included cyanobacteria, organic matter, and turbidity. Results indicated environmental covariates, sensed either remotely or in situ, could be useful to delineate areas with different E. coli survival conditions across irrigation ponds and potentially other water bodies such as lakes, rivers, or bays.

Presence of bacteria and bacteriophages in full-scale trickling filters and an aerated constructed wetland

Aerated Constructed Wetlands are a state-of-the-art design that provides a different physical and chemical environment (compared to traditional passive wetland designs) for the wastewater treatment processes and, thus, may have different pathogen removal characteristics. In order to establish the fate of bacterial and viral indicators, a field study was carried out at a Sewage Treatment Works (STW) in the UK (serving 20,000 pe). The STW consists of primary and secondary sedimentation tanks and trickling filters (TF) as the biological stage. A large (1,160 m²) pilot aerated Vertical Flow Constructed Wetland (AVFCW) was constructed at the STW as tertiary stage receiving ¼ of the total flow rate, i.e., 1250 m³/day. Effluent quality of the AVFCW complied with national and international standards for environmental discharge and reuse. For the first time, two sets of bacterial (Faecal coliforms, E.coli and intestinal enterococci) and viral indicators (Somatic coliphages, F-RNA specific bacteriophages and human-specific B. fragilis GB124 phages) were simultaneously investigated in an AVFCW and TF. High elimination rates were detected (up to 3.7 and 2.2 log reduction for bacteria indicators and phages, respectively) and strong correlations between the two sets were found. The superior efficiency of the aerated Constructed Wetlands in microbiological contamination removal compared to passive wetland systems was established for the first time, which may have implications for process selection for wastewater reuse. This field study therefore provides new evidence on the fate of bacteriophages and a first indication of their potential use for performance evaluation in TF and aerated Constructed Wetlands. It also demonstrates that the combination of TF with aerated constructed wetlands could be a novel and effective treatment scheme for new STW or for the upgrade of existing STW.

Incidence of fecal indicator and pathogenic bacteria in reclaimed and return flow waters in Arizona, USA

The quality of irrigation water used to cultivate produce that is consumed raw is an important issue with regard to food safety. In this study, the microbiological quality of potential irrigation water sources in Arizona was evaluated by testing for the presence of indicator and pathogenic bacteria. Reclaimed water samples were collected from two wastewater treatment plants and return flow samples were collected from two drainage canals and one return flow pond. Standard membrane filtration methods were used for detection of indicator bacteria. Water samples (n = 28) were filtered through cellulose ester membrane filters and bacterial populations were enumerated by placing the filters on selective agar. For detection of pathogens (Salmonella enterica, Listeria monocytogenes and Shiga toxin-producing E. coli (STEC)), water samples were filtered through Modified Moore swabs and enriched in Universal Pre-enrichment Broth, followed by selective enrichment broth for each pathogen. The enriched broth was streaked onto agar media selective for each pathogen. Presumptive colonies were confirmed by PCR/real-time PCR. Among the 14 reclaimed water samples from two sites, the ranges of recovered populations of E. coli, total coliforms, and enterococci were 0-1.3, 0.5-8.3 × 10³, and 0-5.5 CFU/100 mL, respectively. No L. monocytogenes, Salmonella or STEC were found. In the 13 return flow water samples from 3 sites, the ranges of recovered populations of E. coli, total coliforms and enterococci were 1.9-5.3 × 10², 6.5 × 10²-9.1 × 10⁴, and 2.9-3.7× 10³ CFU/100 mL, respectively. All samples were negative for L. monocytogenes. One (7.1%) of the return flow samples was positive for E. coli O145. Nine (64.3%) of the samples were positive for Salmonella. Both real-time PCR and culture-based methods were used for the detection of Salmonella and L. monocytogenes, and the results from the two methods were comparable. The findings of this study provide evidence that irrigation waters in Arizona, including reclaimed water and return flows, could be potential sources of bacterial contamination of produce. Additional work is needed to evaluate whether bacteria present in irrigation water sources transfer to the edible portion of irrigated plants and are capable of persisting through post-harvest activities.

Evaluation of harvested rainwater quality at primary schools of southwest coastal Bangladesh

Rainwater is a typical source of drinking water in the coastal areas of Bangladesh given the acute scarcity of drinking water. This study assessed potability of harvested rainwater of primary schools in southwest coastal Bangladesh. Water samples collected from 23 primary schools of Mongla sub-district under Bagerhat district were evaluated for indicator bacteria (total coliform (TC) and E. coli) and physico-chemical parameters (pH, electrical conductivity, turbidity, total dissolved solid, Fe, Zn, Pb, and Cd). Median concentrations of TC and E. coli in the harvested rainwater samples were respectively 3000 cfu/100 ml and 6 cfu/100 ml. However, concentrations of these indicator bacteria were lower at the consumption points which received a prior treatment. Concentration of Pb exceeded the maximum allowable limit for drinking water indicated by WHO and Bangladesh drinking water guideline value in 92% and 61% of the samples respectively, and the mean concentration was 0.08 mg/l (8 times higher than the WHO guideline value). The Pb contamination possibly occurred from the painting on roof railing and roof stair room. Therefore, consumption of harvested rainwater at primary schools may cause substantial health risk for the school-going children.

Long term development of Bathing Water Quality at the German Baltic coast: spatial patterns, problems and model simulations

Bathing water quality plays a key role for public health, is highly important for recreational tourism and therefore monitored in the EU-Directive 2006/7/EC. To identify pollution hot spots, sources and impacts of the directive-change in 2006, including a change of indicator organisms, we evaluated monitoring data of the past 15 years, collected own data, determined survival rates of indicator organisms and applied hydrodynamic modelling in a micro-tidal-system. Due to higher survival rates under turbid conditions and restricted water exchange, shallow, eutrophic bays and lagoons are hot spots of microbial pollution. Rain events cause high microbial emission and distribution. Based on different decay rates, the ratio of E. coli to Enterococci can hint towards a pollution source. Including rain predictions, currents and winds, hydrodynamic models can then assess the daily risk of microbial pollution at each bathing site. They are an important tool to modify beach management and event-based monitoring.

Precipitation thresholds for fecal bacterial indicators in the Chesapeake Bay

Many coastal states of the United States restrict harvest of shellfish from select areas based on some environmental trigger. Such areas are classified as being conditionally approved. In Maryland, the trigger is an inch or more of rainfall that has fallen in the last 24 h. This study used 11 years of monitoring data to test the relationship between daily rainfall totals and densities of fecal indicators in Maryland shellfish harvest waters. Precipitation and fecal coliform (FC) water monitoring data from 2004 to 2014 were matched by date and watershed. The influence of antecedent rainfall conditions (i.e. rainfall in the preceding days or weeks) and the distance of each monitoring station to land were compared to the percent of samples exceeding the FDA criterion for managing shellfish harvest areas. Sample stations beyond 1000m from land had FC densities consistently below the FDA criterion and were excluded from further analysis. Rainfall events greater than an inch tended to result in significantly elevated FC for the following two days, followed by lower levels thereafter. The total amount of rain in the last three weeks was positively related to the proportion of samples with FC greater than the FDA criterion. Bay-wide, the percent of samples exceeding the FDA criterion rose from seven percent for rainfall less than an inch to 37% following one or more inches of rain. Watersheds were classified based on the percent of FC densities over the criterion when rainfall was an inch or more, with 41 of 81 watersheds showing FC responses indicative of potential conditionally approved areas, those shellfish growing areas where the one inch precipitation trigger may be applied. These areas largely overlapped the current conditionally approved areas defined by Maryland. The percent of open water, wetlands, and poorly drained soils explained a significant amount of the variability (R² = 0.72) in the difference in percent of samples exceeding the FDA criterion when rainfall was greater than an inch and when it was less than an inch. Logistic regression analysis showed that the current trigger of one inch of rain in 24 h is predictive of FC densities over the FDA criterion, though the appropriate threshold will most likely depend on how far the particular shellfish growing area is from land and antecedent rain conditions. In watersheds with relatively high percentages of open water to total watershed size, higher rainfall thresholds might be appropriate. The approach taken in this study could be applied to individual stations and sub-watersheds, potentially allowing the reclassification of some shellfish harvest areas.

Anaerobic co-digestion of pig manure and food waste; effects on digestate biosafety, dewaterability, and microbial community dynamics

This study assessed the effect of varying pig manure (PM)/food waste (FW) mixing ratio and hydraulic retention time (HRT) on methane yields, digestate dewaterability, enteric indicator bacteria and microbial communities during anaerobic co-digestion. Three 10 L digesters were operated at 39 °C, each with a PM/FW feedstock composition of 85%/15%, 63%/37% and 40%/60% (volatile solids basis). While the PM/FW ratio was different among reactors, the organic loading rate applied was equal, and increased stepwise with reducing HRT. The effects of three different HRTs were studied: 41, 29, and 21 days. Increasing the proportion of FW in the feedstock significantly increased methane yields, but had no significant effect on counts of enteric indicator bacteria in the digestate or specific resistance to filtration, suggesting that varying the PM/FW feedstock composition at the mixing ratios studied should not have major consequences for digestate disposal. Decreasing HRT significantly increased volumetric methane yields, increased digestate volatile solids concentrations and increased the proportion of particles >500 µm in the digestate, indicating that decreasing HRT to 21 days reduced methane conversion efficiency High throughput 16S rRNA sequencing data revealed that microbial communities were just slightly affected by changes in digester operating conditions. These results would provide information useful when optimizing the start-up and operation of biogas plants treating these substrates.

Inactivation of microbiota from urban wastewater by single and sequential electrocoagulation and electro-Fenton treatments

This work aims at comparing the ability of two kinds of electrochemical technologies, namely electrocoagulation (EC) and electro-Fenton (EF), to disinfect primary and secondary effluents from municipal wastewater treatment plants. Heterotrophic bacteria, Escherichia coli, enterococci, Clostridium perfringens spores, somatic coliphages and eukaryotes (amoebae, flagellates, ciliates and metazoa) were tested as indicator microorganisms. EC with an Fe/Fe cell at 200 A m^-2 and natural pH allowed >5 log unit removal of E. coli and final concentration below 1 bacteria mL^-1 of coliphages and eukaryotes from both effluents in ca. 60 min, whereas heterotrophic bacteria, enterococci and spores were more resistant. A larger removal was obtained for the primary effluent, probably because the flocs remove higher amount of total organic carbon (TOC), entrapping more easily the microbiota. EF with a boron-doped diamond (BDD) anode and an air-diffusion cathode that produces H₂O₂ on site was first performed at pH 3.0, with large or even total inactivation of microorganisms within 30 min. A more effective microorganism removal was attained as compared to EC thanks to ^•OH formed from Fenton's reaction. A quicker disinfection was observed for the secondary effluent owing to its lower TOC content, allowing the attack of greater quantities of electrogenerated oxidants on microorganisms. Wastewater disinfection by EF was also feasible at natural pH (∼7), showing similar abatement of active microorganisms as a result of the synergistic action of generated oxidants like active chlorine and coagulation with iron hydroxides. A sequential EC/EF treatment (30 min each) was more effective for a combined decontamination and disinfection of urban wastewater.

Monitoring bacterial contamination of piped water supply in rural coastal Bangladesh

Safe drinking water is scarce in southwest coastal Bangladesh because of unavailability of fresh water. Given the high salinity of both groundwater and surface water in this area, harvested rainwater and rain-fed pond water became the main sources of drinking water. Both the government and non-government organizations have recently introduced pipe water supply in the rural coastal areas to ensure safe drinking water. We assessed the bacteriological quality of water at different points along the piped water distribution system (i.e., the source, treatment plant, household taps, street hydrants, and household storage containers) of Mongla municipality under Mongla Upazila in Bagerhat district. Water samples were collected at 2-month interval from May 2014 to March 2015. Median E. coli and total coliform counts at source, treatment plant, household taps, street hydrants, and household storage containers were respectively 225, 4, 7, 7, and 15 cfu/100 ml and 42,000, 545, 5000, 6150, and 18,800 cfu/100 ml. Concentrations of both of the indicator bacteria reduced after treatment, although it did not satisfy the WHO drinking water standards. However, re-contamination in distribution systems and household storage containers indicate improper maintenance of distribution system and lack of personal hygiene.

Assessing the seawater quality of a coastal city using fecal indicators and environmental variables (eastern Aegean Sea)

The presence of fecal bacteria in seawater is one of the most important bio-indicator parameters of fecal pollution. In this study, the Bay of İzmir (in the eastern Aegean Sea), which is a critical area because of its relationship with marine transportation and industrial and commercial activities, was evaluated for its microbiological and physicochemical parameters through a monitoring program. The data were obtained from seasonally assembled surface seawater samples from 2015 to 2017 at 23 sampling stations. Bacteriological investigations were performed by membrane filtration technique. During the monitoring period, for stations at the inner and middle-outer part, it was found that the inner part is exposed to more number of fecal coliforms (8.8×10²cfu/100mL) and fecal streptococci (1.1×10³cfu/100mL). The monitoring analysis performed in this study showed that there was negative correlation between physicochemical parameters and the level of fecal bacteria, but no significance was recorded by the Pearson correlation test. Fecal contamination parameters should be routinely monitored for improving the environmental conditions of coastal cities.

Bacteriological safety assessment, hygienic habits and cross-contamination risks in a Nigerian urban sample of household kitchen environment

Urban household kitchen environment was assessed for safety by determining their levels of indicator bacteria, hygienic habits and risk of cross-contamination. Household kitchens (60) were selected in Warri Town, Nigeria, by the multi-stage sampling technique. Contact surfaces, water and indoor kitchen air were analysed for aerobic plate counts, total and faecal coliforms using Nutrient and McConkey media by swab/rinse method, membrane filtration and sedimentation methods, respectively. Hygienic habits and risk of cross-contamination were assessed with structured questionnaire which included socio-demographic variables. On the basis of median counts, the prevalence of high counts (log cfu/cm²/m³/100 mL) of aerobic plate counts (>3.0), total coliforms (>1.0) and faecal coliforms (>0) on contact surfaces and air was high (58.0-92.0%), but low in water (30.0-40.0%). Pots, plates and cutleries were the contact surfaces with low counts. Prevalence of poor hygienic habits and high risk of cross-contamination was 38.6 and 67.5%, respectively. Education, occupation and kitchen type were associated with cross-contamination risk (P = 0.002-0.022), while only education was associated with hygienic habits (P = 0.03). Cross-contamination risk was related (P = 0.01-0.05) to aerobic plate counts (OR 2.30; CL 1.30-3.17), total coliforms (OR 5.63; CL 2.76-8.25) and faecal coliforms (OR 4.24; CL 2.87-6.24), while hygienic habit was not. It can be concluded that urban household kitchens in the Nigerian setting are vulnerable to pathogens likely to cause food-borne infections.

Indicator bacteria community in seawater and coastal sediment: the Persian Gulf as a case

BACKGROUND

The aim of present work was to assess the concentration levels as well as vertical distribution of indicator bacteria including total coliform, fecal coliform, Pseudomonas aeruginosa, and Heterotrophic Plate Count (HPC) in the marine environment (seawater and coastal sediments) and evaluate the correlation between indicator bacteria and some physicochemical parameters of surface sediments as well as seawaters.

METHODS

A total number of 48 seawater and sediment samples were taken from 8 stations (each site 6 times with an interval time of 2 weeks) between June and September 2014. Seawater and sediment samples were collected from 30 cm under the surface samples and different sediment depths (0, 4, 7, 10, 15, and 20 cm) respectively, along the Persian Gulf in Bushehr coastal areas.

RESULTS

Based on the results, the average numbers of bacterial indicators including total coliform, fecal coliform, and Pseudomonas aeruginosa as well as HPC in seawater samples were 1238.13, 150.87, 8.22 MPN/100 ml and 1742.91 CFU/ml, respectively, and in sediment samples at different depths (from 0-20 cm) varied between 25 × 10³ to 51.67 × 10³, 5.63 × 10³ to 12.46 × 10³, 17.33 to 65 MPN/100 ml, 36 × 10³ to 147.5 × 10³ CFU/ml, respectively. There were no statistically significant relationships between the indicator organism concentration levels with temperature as well as pH value of seawater. A reverse correlation was found between the level of indicator bacteria and salinity of seawater samples. Also results revealed that the sediment texture influenced abundance of indicators bacteria in sediments. As the concentration levels of indicators bacteria were higher in muddy sediments compare with sandy ones.

CONCLUSION

Result conducted Bushehr coastal sediments constitute a reservoir of indicator bacteria, therefore, whole of the indicators determined were distinguished to be present in higher levels in sediments than in the overlying seawater. It was concluded that the concentration levels of microbial indicators decreased with depth in sediments. Except total coliform, the numbers of other bacteria including fecal coliform, Pseudomonas aeruginosa and HPC bacteria significantly declined in the depth between 10 and 15 cm.

Detection of hepatitis E virus and other livestock-related pathogens in Iowa streams

Manure application is a source of pathogens to the environment. Through overland runoff and tile drainage, zoonotic pathogens can contaminate surface water and streambed sediment and could affect both wildlife and human health. This study examined the environmental occurrence of gene markers for livestock-related bacterial, protozoan, and viral pathogens and antibiotic resistance in surface waters within the South Fork Iowa River basin before and after periods of swine manure application on agricultural land. Increased concentrations of indicator bacteria after manure application exceeding Iowa's state bacteria water quality standards suggest that swine manure contributes to diminished water quality and may pose a risk to human health. Additionally, the occurrence of HEV and numerous bacterial pathogen genes for Escherichia coli, Enterococcus spp., Salmonella sp., and Staphylococcus aureus in both manure samples and in corresponding surface water following periods of manure application suggests a potential role for swine in the spreading of zoonotic pathogens to the surrounding environment. During this study, several zoonotic pathogens were detected including Shiga-toxin producing E. coli, Campylobacter jejuni, pathogenic enterococci, and S. aureus; all of which can pose mild to serious health risks to swine, humans, and other wildlife. This research provides the foundational understanding required for future assessment of the risk to environmental health from livestock-related zoonotic pathogen exposures in this region. This information could also be important for maintaining swine herd biosecurity and protecting the health of wildlife near swine facilities.

Evaluation of the distribution of fecal indicator bacteria in a river system depending on different types of land use in the southern watershed of the Baltic Sea

The aim of the study was to determine the effects of land use management on changes in the fecal contamination of water in the Łyna River, one of the main lowland watercourses in the southern watershed of the Baltic Sea (northern Poland). A total of 120 water samples were collected in different seasons of 2011 and 2012 at 15 sites where the river intersected forest (FA), agricultural (AA), and urbanized (UA) areas. Fecal indicator bacteria (FIB), the counts of Enterobacteriaceae and Escherichia coli, total bacterial counts (TBCs), and domain Bacteria (EUB338) were determined by culture-dependent and culture-independent methods. Temperature, pH, chemical oxygen demand, dissolved oxygen, total dissolved solids, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, orthophosphate, and total phosphorus were also determined. The lowest bacterial counts were noted in water samples collected in FA, and the highest in samples collected in UA. Statistically significant differences were determined between bacterial populations across the analyzed land use types and in different sampling seasons. Significant correlations were also observed between the populations of FIB and physicochemical parameters. The results indicate that land use type influenced FIB concentrations in river water. The combined use of conventional and molecular methods improves the accuracy of fecal contamination analyses in river ecosystems.

Irrigation waters and pipe-based biofilms as sources for antibiotic-resistant bacteria

The presence of antibiotic-resistant bacteria in environmental surface waters has gained recent attention. Wastewater and drinking water distribution systems are known to disseminate antibiotic-resistant bacteria, with the biofilms that form on the inner-surfaces of the pipeline as a hot spot for proliferation and gene exchange. Pipe-based irrigation systems that utilize surface waters may contribute to the dissemination of antibiotic-resistant bacteria in a similar manner. We conducted irrigation events at a perennial stream on a weekly basis for 1 month, and the concentrations of total heterotrophic bacteria, total coliforms, and fecal coliforms, as well as the concentrations of these bacterial groups that were resistant to ampicillin and tetracycline, were monitored at the intake water. Prior to each of the latter three events, residual pipe water was sampled and 6-in. sections of pipeline (coupons) were detached from the system, and biofilm from the inner-wall was removed and analyzed for total protein content and the above bacteria. Isolates of biofilm-associated bacteria were screened for resistance to a panel of seven antibiotics, representing five antibiotic classes. All of the monitored bacteria grew substantially in the residual water between irrigation events, and the biomass of the biofilm steadily increased from week to week. The percentages of biofilm-associated isolates that were resistant to antibiotics on the panel sometimes increased between events. Multiple-drug resistance was observed for all bacterial groups, most often for fecal coliforms, and the distributions of the numbers of antibiotics that the total coliforms and fecal coliforms were resistant to were subject to change from week to week. Results from this study highlight irrigation waters as a potential source for antibiotic-resistant bacteria, which can subsequently become incorporated into and proliferate within irrigation pipe-based biofilms.

Carriage of Clostridium perfringens by benthic crabs in a sewage-polluted estuary

The Estuary of Bahía Blanca (EBB), Argentina, is an important wetland under intense sewage pollution. We investigated the occurrence of Clostridium perfringens (CP) in populations of two benthic crabs (Neohelice granulata and Cyrtograpsus angulatus) and in sediment from the EBB. CP was found in 49.1% of the crabs and all of the isolates were identified as type A. The alpha (cpa) and enterotoxin (cpe) encoding genes were identified. Genetic analyses identified 13 novel sequence types, and found no clustering among isolates, suggesting that CP is not part of the crabs' commensal flora. CP carriage was 51 times more likely in crabs from the area nearest sewage outfalls compared with crabs from a reference site. Our in vitro experiments suggest that the carriage of CP in crabs is transient. The use of these benthic crabs as monitoring organisms of sewage pollution in coastal habitats is proposed.

Distinct behaviors of infectious F-specific RNA coliphage genogroups at a wastewater treatment plant

The present study aimed to determine the differences in the behaviors of four F-specific RNA (F-RNA) coliphage genogroups (GI-GIV) during wastewater treatment. Raw sewage, aeration tank effluent, secondary-treated sewage, and return activated sludge were collected from a wastewater treatment plant in Japan at monthly intervals between March and December 2011 (n=10 each). F-specific coliphages were detected by plaque assay in all tested samples, with a concentration ranging from -0.10 to 3.66 log10 plaque-forming units/ml. Subsequently, eight plaques were isolated from each sample, followed by genogroup-specific reverse-transcription quantitative PCR (qPCR) for F-RNA coliphages and qPCR for F-specific DNA (F-DNA) coliphages. GI F-RNA coliphages were the most abundant in the secondary-treated sewage samples (73% of the plaque isolates), while GII F-RNA coliphages were the most abundant in the other three sample types (41-81%, depending on sample type). Based on the results of the quantification and genotyping, the annual mean concentrations of each F-specific coliphage type were calculated, and their reduction ratios during wastewater treatment were compared with those of indicator bacteria (total coliforms and Escherichia coli) and enteric viruses (human adenoviruses and GI and GII noroviruses). The mean reduction ratio of GI F-RNA coliphages was the lowest (0.93 log10), followed by those of the indicator bacteria and enteric viruses (1.59-2.43 log10), GII-GIV F-RNA coliphages (>2.60-3.21 log10), and F-DNA coliphages (>3.41 log10). These results suggest that GI F-RNA coliphages may be used as an appropriate indicator of virus reduction during wastewater treatment.

Relationships among hygiene indicators and enteric pathogens in irrigation water, soil and lettuce and the impact of climatic conditions on contamination in the lettuce primary production

Eight Belgian lettuce farms located in the West Flanders were sampled to establish the relationships between levels of indicator bacteria, detection of enteric zoonotic pathogens and the temperature and precipitation during primary production. Pathogenic bacteria (PCR EHEC positives, Salmonella spp. or Campylobacter spp.) and indicator bacteria (total psychrotrophic aerobic plate count (TPAC), total coliforms, Escherichia coli, enterococci) were determined over a period of one and a half year from seedling leaves, peat-soil of the seedling, lettuce crops, field soil and irrigation water. Neither Salmonella isolates nor PCR EHEC signals were detected from lettuce although one out of 92 field soil samples contained Salmonella spp. and five soil samples provided PCR positives for EHEC virulence factors (vt1 or vt2 and eae gene). A low prevalence of Campylobacter (8/88) was noted in lettuce. It was shown that irrigation water is a major risk factor with regard to the bacterial contamination of the fresh produce as the water samples showed on a regular basis E. coli presence (59.2% of samples≥1CFU/100ml) and occasionally detection of pathogens (25%, n=30/120), in particular Campylobacter spp. The highest correlations between indicator bacteria, pathogens, temperature and the amount of precipitation were observed for the water samples in contrast to the soil or lettuce samples where no correlations were observed. The high correlations between E. coli, total coliforms and enterococci in the water implicated redundancy between analyses. Presence of elevated levels of E. coli increased the probability for the presence of pathogens (Campylobacter spp., EHEC and Salmonella spp.), but had a low to moderate predictive value on the actual presence of pathogens. The presence of pathogens and indicator bacteria in the water samples showed a seasonal effect as they tend to be more present during the months with higher temperature.

Fast coliform detection in portable microbe enrichment unit (PMEU) with Colilert(®) medium and bubbling

Laboratory strains of coliforms Escherichia coli and Klebsiella mobilis were used to artificially contaminate water samples in two different cultivation and detection systems, without and with bubble flow. Samples were collected with an automated system (ASCS). The positive coliform signal caused the color change into yellow (at 550-570nm). This signal could also be transmitted on-line to cell phones. E. coli containing samples emitted UV fluorescence at 480-560nm when activated by UV light. If cultivation was started with inocula varying from 10,000 to 1cfu/ml, the positive detection was obtained between 2 and 18h, respectively, in Colilert medium using Coline PMEU device without gas bubbling. Accordingly, a single K. mobilis cell produced detectable growth in 18h. Various clinical E. coli strains were compared to each other with equal inoculum sizes, and they showed slight variations in the initiation and speed of growth. The gas bubble flow in PMEU Spectrion promoted the mixing and interaction of bacteria and indicator media and speeded the onset of growth. Carbon dioxide also accelerated bacterial growth. In the presence of vancomycin, the onset of E. coli culture growth was speeded up by the volatile outlet flow from previous cultures. In the last cultivation syringe in a series of five, the lag phase disappeared and the growth of the inoculum continued without major interruption.

IN CONCLUSION

the stimulation of the cultures by the gas flow turned out to be a useful means for improving the detection of indicator bacteria. It could also be used in combination with antibiotic selection in the broth medium.