An integrated appraisement of multiple faecal indicator bacteria and sterols in the detection of sewage contamination in subtropical tidal creeks

The quality of water bodies has been regulated by national environmental agencies and based on faecal indicator bacteria, such as thermotolerant coliforms Escherichia coli and Enterococcus sp. Additionally, faecal sterols (mainly coprostanol) have been used to corroborate sewage discharge in marine environments. In this study, faecal material input was evaluated in two sampling campaigns in transects of two tidal creeks using bacterial and chemical indicators to both compare and establish the water quality in a South Atlantic subtropical estuary. The Itiberê tidal creek (S1) was classified as “contaminated” by faecal material, while the Peças tidal creek (S2) presented variable water quality according to the sampling period and sewage indicators considered in this evaluation. Then, the integrated application of chemical and bacterial indicators was applied for tidal creeks with different sewage contamination levels and under distinct environmental conditions and confirmed that Enterococcus sp. and coprostanol are the most suitable for estuarine environments.     

Food Safety Issues: A Summary Report of a Panel Session Addressing Pre- and Post-Harvest Strategies to Improve Public Health

ABSTRACT

The paper presents a summary of a panel presentation by animal scientists and public health veterinarians on food safety methods to improve public health of the public consuming beef and poultry. Pre-harvest methods discussed include vaccination to decrease shedding of Esherichia coli O157:H7, direct-fed microbials (DFMs), calving methods, and responsible use of antimicrobials. Post-harvest methods discussed include increased sampling and use of hazard analysis and critical control point (HACCP) methods, test-and-hold of meat products prior to release for public consumption, development of attainment categories, the use of pulsed field gel electrophoresis (PFGE) for genotyping and serotyping, and an 11-step surveillance program. The public health concern and financial consequences of contamination with E. coli O157:H7 is discussed. A “carrot and stick” approach for both producers and processors to increase vaccination and product testing is recommended.     

Evaluation of the Colilert® Test for Detection of Verotoxin-Producing Escherichia coli in Water

ABSTRACT

The objective of this study was to estimate the sensitivity of the Colilert® test for detection of different isolates of Escherichia coli (E. coli) O157:H7 and other verotoxin-producing E. coli (VTEC) serotypes from water for potential on-farm food safety application. E. coli isolates evaluated were of human, bovine, porcine, or food origin. The sensitivity of the Colilert® test was 92% overall for the verotoxin-producing serotypes of E. coli. However, none of the E. coli O157:H7 isolates were identified as E. coli. No false-positive results for E. coli were detected. The Colilert® test could be used to screen water supplies for E. coli on the farm, however, an important pathogenic E. coli sero-type is not detected by the Colilert® test.     

Variations in microbial indicator densities in beach waters and health-related assessment of bathing water quality

Daily and hourly variations in microbial indicators densities in the beach-waters of Hong Kong have been described. The levels of Escherichia coli at a number of beaches was observed to be influenced by tide, and for staphylococci, by bather numbers. The tidal influence was most obvious during spring tides; and for the effect of bathers, during neap tides. Both organisms are present in high densities in external sources of faecal pollution of bathing beaches, with the average staphylococci to E. coli ratios being 0.04-3. Staphylococci may serve as an indicator of bather density and the risk of cross-infection amongst bathers (rather than as another indicator of faecal contamination) when the average staphylococci to E. coli ratio for a bathing beach is considerably higher than 3. The variability of microbial indicator densities means the routine sampling of bathing beaches should be carried out on weekend days with maximum numbers of swimmers exposed to the water, and spread throughout the bathing season.     

上海市2012－2013年4种致泻性大肠埃希菌监测

目的 基于临床医院开展4种致泻性大肠埃希菌(DEC)人群监测,探讨公共卫生实验室对临床实验室需求的直接技术指导的实践模式。方法 设立哨点医院,以标准化方法筛选和鉴定DEC菌型;构建DEC流行特征基线;对疑似暴发病例开展基于实验室和流行病学调查。结果 2012－2013年选择上海地区4家哨点医院检测7 204份腹泻标本确认的712例DEC感染病例,阳性率为9.9%。其中肠致病性大肠埃希菌(EPEC)感染351例;肠产毒性大肠埃希菌(ETEC)感染292例;肠侵袭性大肠埃希菌(EIEC)感染32例;产志贺样毒素大肠埃希菌(STEC/EHEC)感染6例;DEC混合感染31例。EPEC感染以1～5岁儿童最多见,菌型均为aEPEC;ETEC流行峰值在8月,阳性率>20%,感染病例2012年聚集于1～28日龄和2013年的20～60岁人群(P< 0.05),菌型以耐热肠毒素(ST)型最多(59.6%),其次为不耐热肠毒素(LT)型(27.8%)和ST/LT型(12.6%);2013年儿童感染EIEC病例明显增加(P< 0.01);未监测到EHEC O157 : H7,但确认2例EHEC O26 : H11(eae-hlyA-stx1a)儿童病例;调查确认2012年上海地区15例新生儿ETEC聚集性感染病例与四川省自贡市新生儿病例属于同一克隆(STh-CS21-CFA/I-ClyA-EatA-ST2332- SHNL0005)。结论 上海地区DEC型谱特征已发生改变,ETEC对新生儿院内感染和食源性感染性腹泻构成潜在暴发风险,需加强实验室主动监测。     

Tidal Cycles of Total Particulate Mercury in the Jade Bay, Lower Saxonian Wadden Sea, Southern North Sea

In this study, we evaluate the nature of the relationship between particulate matter and total mercury concentrations. For this purpose, we estimate both of the two values in water column over 12–h tidal cycles of the Jade Bay, southern North Sea. Total particulate mercury in 250 mL water samples was determined by oxygen combustion-gold amalgamation. Mercury contents varied from 63 to 259 ng/g suspended particulate matter (SPM) or 3.5–52.8 ng/L in surface waters. Total particulate mercury content (THg_p) was positively correlated with (SPM), indicating that mercury in tidal waters is mostly associated with (SPM), and that tidal variations of total particulate mercury are mainly due to changes in (SPM) content throughout the tidal cycle. Maximum values for THg_p were observed during mid-flood and mid-ebb, while the lowest values were determined at low tide and high tide. These data suggest that there are no mercury point sources in the Jade Bay. Moreover, the THg_p content at low tide and high tide were significantly lower than the values recorded in the bottom sediment of the sampling site (>200 ng/g DW), while THg_p content during the mid-flood and mid-ebb were comparable to the THg content in the surface bottom sediments. Therefore, changes in THg_p content in the water column due to tidal forcing may have resulted from re-suspension of underlying surface sediments with relatively high mercury content.     

Detection and source tracking of Escherichia coli,harboring intimin and Shiga toxin genes,isolated from the Little Bighorn River,Montana

The Little Bighorn River flows through the Crow Indian Reservation in Montana. In 2008, Escherichia coli concentrations as high as 7179 MPN/100 ml were detected in the river at the Crow Agency Water Treatment Plant intake site. During 2008, 2009, and 2012, 10 different serotypes of E. coli, including O157:H7, harboring both intimin and Shiga toxin genes were isolated from a popular swim site of the Little Bighorn River in Crow Agency. As part of a microbial source tracking study, E. coli strains were isolated from river samples as well as from manure collected from a large cattle feeding operation in the upper Little Bighorn River watershed; 23% of 167 isolates of E. coli obtained from the manure tested positive for the intimin gene. Among these manure isolates, 19 were identified as O156:H8, matching the serotype of an isolate collected from a river sampling site close to the cattle feeding area.     

Assessing spatial fluctuations, temporal variability, and measurement error in estimated levels of disinfection by-products in tap water: implications for exposure assessment

Aims: To assess spatial fluctuations, temporal variability, and errors due to sampling and analysis in levels of disinfection by-products in routine monitoring tap water samples and in water samples collected in households within the same distribution system for an exposure assessment study.

Methods: Mixed effects models were applied to quantify seasonal effects and the degree to which trihalomethane (THM) levels vary among households or locations relative to variation over time within seasons for any given location. In a separate analysis, the proportion of total variation due to measurement error arising from sampling and analysis was also quantified.

Results: THM levels were higher in the summer relative to other seasons. Differences in the relative magnitude of the intra- and inter-household components of variation were observed between the two sets of THM measurements, with a greater proportion of the variation due to differences within seasons for the routine monitoring data and a greater proportion of the variation due to differences across locations for the exposure assessment study data. Such differences likely arose due to differences in the strategies used to select sites for sampling and in the time periods over which the data were collected. With the exception of bromodichloromethane, measurement errors due to sampling and analysis contributed a small proportion of the total variation in THM levels.

Conclusions: The utility of routine monitoring data in assigning exposure in epidemiological studies is limited because such data may not represent the magnitude of spatial variability in levels of disinfection by-products across the distribution system. Measurement error contributes a relatively small proportion to the total variation in THM levels, which suggests that gathering a greater number of samples over time with fewer replicates collected at each sampling location is more efficient and would likely yield improved estimates of household exposure.

     

Improving cardiovascular health in the German CINDI area: Methods and results of the practice-based ‘Three-Level Strategy’ (CINDI equals; Countrywide Integrated Noncommunicable Diseases Intervention programme of the WHO)

Objectives: To evaluate the German intervention model of ‘Three-Level Strategy’ especially in reducing cardiovascular risk during a major prevention study (study phase I) and to investigate the feasibility and efficiency of a new system that provides continuous ‘self-evaluation’ of general practitioners cooperating in intervention (study phase II).

Methods: Primary care setting in the CINDI intervention area with a population of about 45,000 and a control town in phase I, subsequently (phase II) in a smaller part of this area. Cross-sectional investigations by means of random sampling on the population level (phase I) and in practices (phase II). Intervention with the ‘Three-Level Strategy of General Practitioners’ method comprising individual health consultation (1st level), supplemented by groupwork with the patients (2nd level) and community-oriented influencing of lifestyle by GPs at the 3rd level. Evaluation of this intervention strategy within the German Cardiovascular Prevention Study (GCP, 1985–1992) in phase I; since 1992, intervention, monitoring, and evaluation in seven practices in one community (phase II).

Main outcome measures were besides assessing health behaviour by a questionnaire, reduction of the four CVD risk factors, namely smoking, obesity (BMI ≥30), hypertension (WHO criteria), and hypercholesterolaemia (≥250 mg/dl).

Results: In the intervention town of phase I (GCP evaluation), in contrast to the control town, the cardiovascular risk factors were reduced: smoking (-9.4%), obesity (-17.1%), hypertension (-51.4%) and hypercholesterolaemia (-12.8%). In the practices of the smaller area, from 1992 to 1994, (phase II), the prevalence of smoking (-23.2%, p <0.01) as well as hypertension (-22.1%, p<0.01) decreased too; there was no further reduction of hypercholesterolaemia and obesity. Special health groups improved health behaviour.

Conclusions: The practice-based intervention model of general practitioners proved to be effective (GCP, phase I). Close cooperation of GPs enables the setting up of a continuous monitoring and evaluation system and facilitates further success without noticeable costs (phase II). The annual determination and analysis of medical data and health services give information on the health-related behaviour in the GP clientele and approximate information on the local population.     

Screening of tropical estuarine water in south-west coast of India reveals emergence of ARGs-harboring hypervirulent Escherichia coli of global significance

The goal of this study was to investigate the involvement of a tropical Indian estuary in the emergence of antibiotic resistance genes (ARGs)-harboring hypervirulent E. coli of global significance. A total of 300 E. coli isolates was tested for antibiotic susceptibility to β-lactams, aminoglycosides, chloramphenicol, quinolones, sulphonamides, tetracyclines, and trimethoprim. The E. coli isolates were screened for the presence of antibiotic resistance genes (bla_TEM, bla_CTX-M, tetA, tetB, sul1, sul2, strA, aphA2, catI, dhfr1, and dhfr7), integrase (int1, int2, and int3), Shiga toxin genes (stx1 and stx2) and extraintestinal virulence genes (papAH, papC, sfa/focDE, kpsMT II, and iutA). The highest prevalence of antibiotic resistance was observed for ampicillin, followed by tetracycline, and nalidixic acid. Among E. coli isolates, 64% were resistant to at least one of the 15 antibiotics tested, and approximately 40% were multiple antibiotic-resistant (MAR). More than 40% (n?=?122) of E. coli isolates had ARGs. Integrase 1 (int1) was found in 7.6% of E. coli isolates. Among E. coli isolates, 16.3% (n?=?49) were extraintestinal pathogenic E. coli (ExPEC), and approximately 34.6% (n?=?17) of ExPEC had ARGs. A hypervirulent ARGs-harboring STEC was isolated. The prevalence of Shiga toxin-producing E. coli (STEC) was low (n?=?1). The prevalence of ARGs-harboring pathogenic E. coli isolates was higher in stations close to the City (urban area), than that of other stations. ERIC-PCR (enterobacterial repetitive intergenic consensus sequence polymerase chain reaction) analysis revealed a high degree of genetic diversity among the ARGs-harboring E. coli isolates. The results demonstrate a high prevalence of ARGs-harboring E. coli in estuarine water and confirm the need for a better wastewater treatment facility and proper control measures to reduce the discharge of sewage and wastewater into the aquatic environments.     

Mercury Distribution in Contaminated Surface Sediments from Four Estuaries,Khuzestan Shore,North Part of Persian Gulf

The distribution of mercury in surface sediment from four estuaries along the Khuzestan shore, north part of Persian Gulf, was measured. The concentration of mercury varied among sampling stations (p < 0.05). The concentrations of mercury in all estuaries were from 0.01 to 2.16 µg g^?1. Relatively high mercury concentrations were observed in sediments from Musa estuary. The percentage of mercury associated with different fractions in the sediment from all stations were in the order of residual (70.4 %) > organic matter (16.6 %) > easily and exchangeable (2.2 %) > acid reduction (0.8 %). I _geo values calculated for mercury (1.5) showed higher values in Musa estuary than in the other stations. The bioavailability of mercury in sediments could be controlled by physicochemical factors such as pH, oxidation and reduction potential, organic carbon content and cation exchange capacity.     

The effects of urbanization on small high salinity estuaries of the southeastern United States

Future development in coastal areas of the southeastern United States (US) will likely result from urbanization (housing and tourist/service related activities) rather than industrialization. In an effort to identify potential impacts associated with urbanization, field studies were conducted in two small, high salinity estuaries of coastal South Carolina. The sites selected for study were Murrells Inlet, an estuary with a history of significant urbanization and North Inlet, a relatively pristine, undisturbed estuary. During field studies conducted in the fall of 1990, a series of 96-h in situ bioassays were undertaken at each of the sites. The species used were the grass shrimp, Palaemonetes pugio, and the mummichog, Fundulus heteroclitus. Water samples were collected at the site during these bioassays and analyzed for polyaromatic hydrocarbons (PAH) residues. Adult oysters, Crassostrea virginica, were also deployed at each of the sites during the in situ bioassays and analyzed for tissue PAH residues. Physicochemical water quality and rainfall were also monitored. Mean waterborne PAH levels were significantly higher at the urbanized Murrells Inlet site than at the more pristine North Inlet. Additionally, oysters deployed at the Murrells Inlet site showed increased PAH levels in comparison to baseline values while those deployed at the North Inlet had PAH levels well below baseline concentrations. No siterelated mortality was observed in the two species used in the bioassays. Fluctuations in salinity, dissolved oxygen, and pH were much less extreme at the urbanized Murrells Inlet site than at North Inlet. The less dynamic physicochemical environment at the Murrells Inlet site may be due in part to urban influences (i.e., jetty construction and bulkheading). Additional work is needed to better define the significance of these observations.     

The impact of rainfall and seasonal variability on the removal of bacteria by a point-of-use drinking water treatment intervention in Chennai,India

Point-of-use water treatment has received widespread application in the developing world to help mitigate waterborne infectious disease. This study examines the efficacy of a combined filter and chemical disinfection technology in removing bacterial contaminants, and more specifically changes in its performance resulting from seasonal weather variability. During a 12-month field trial in Chennai, India, mean log-reductions were 1.51 for E. coli and 1.67 for total coliforms, and the highest concentration of indicator bacteria in treated water samples were found during the monsoon season. Analysis of variance revealed significant differences in the microbial load of indicator organisms (coliforms and E. coli) between seasons, storage time since treatment (TST), and samples with and without chlorine residuals. Findings indicate that the bacteriological quality of drinking water treated in the home is determined by a complex interaction of environmental and sociological conditions. Moreover, while the effect of disinfection was independent of season, the impact of storage TST on water quality was found to be seasonally dependent.     

Faecal contamination of a tropical river in Nigeria and possible health risks

Information on the hygienic status of surface water is a major public health priority in tropical developing countries. The incidence and occurrence of indicator organisms and pathogenic Salmonellae were studied in a tropical river, the Kaduna, Nigeria, affected by urban waste‐water discharges mainly through open surface drains. The results indicate gross faecal contamination of both the urban waste‐water discharges and the receiving river. By using FC:FS ratios to determine the faecal pollution origin, it was evident that both human and animal sources pollute the river. This signifies that both sources of pollution should be considered in setting bacteriological standards for the waste‐water‐receiving surface water. Klebsiella and Escherichia spp. had similar frequencies of occurrence in the river. The urban effluent receiving river also carried Klebsiella pneumonia, Escherichia coli and pathogenic Salmonella spp. It was concluded that the use of urban waste‐water discharges and the receiving river for irrigation, recreation and water supply poses health risks to the public.     

Multiple water source use in rural Vanuatu: are households choosing the safest option for drinking?

Households in low- and middle-income countries commonly make use of multiple water sources. However, it remains unclear to what extent their drinking water choices are optimal from a health perspective. This matched cohort study across 10 islands in Vanuatu examined communities with both a groundwater and rainwater source to determine whether their preferred drinking option was the safest in microbial terms. In communities that preferred to drink rainwater, 56.5% of rainwater sources had ‘high-risk’ or ‘very high risk’ Escherichia coli contamination (> 10 MPN/100 mL) compared with 26.1% of groundwater sources (p = 0.092). Moreover, a preference for drinking rainwater was significantly associated with rainwater sources having ‘high-risk’ or ‘very high risk’ levels of E. coli contamination (p = 0.045). Results show that communities do not necessarily choose the safest water source for drinking. Findings also highlight the need to bolster local capacity to manage water quality risks and for Sustainable Development Goal monitoring to distinguish between protected and unprotected rainwater tanks.     

A review of surface wipe sampling compared to biologic monitoring for occupational exposure to antineoplastic drugs

The potential for adverse health effects from occupational exposure to antineoplastic drugs (AD) is well known. Control measures recommended by the NIOSH Alert^[3] NIOSH: Preventing occupational exposures to antineoplastic and other hazardous drugs in healthcare settings 2004. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health DHHS (NIOSH) Publication No 2004 (165) (2004). [Google Scholar] include medical and biologic monitoring, and environmental monitoring where available. At present no guidelines or published best practices exist to guide EHS managers on how to carry out this biologic or environmental monitoring. Studies investigating surface wipe sampling for AD have been numerous in the past decade, but very limited research exists to correlate surface contamination with actual absorption by pharmacists and nurses.

This article reviews the studies with concurrent surface wipe sampling and urine monitoring for the same AD, and tests their correlation. Methodologic limitations are reviewed.

Twenty-one studies were identified that concurrently measured surface contamination by AD by wipe sampling and AD absorption by urine monitoring. Two studies directly evaluated the AD by wipe sampling and urine levels and neither found a statistically significant correlation. Six studies reported a decrease in both surface and urine levels following interventions to reduce contamination or exposure. Only one study directly evaluated the personal protective equipment and handling techniques employed by the studied workers, which can be viewed as a major confounder of absorption.

While no statistically significant correlation was found between wipe sampling and urine monitoring for AD, decreases in urine and wipe levels following interventions to reduce exposure were noted. Limitations in the data and recommendations for future research are reviewed.     

Different responses of Ross River virus to climate variability between coastline and inland cities in Queensland,Australia

Aims: To examine the potential impact of climate variability on the transmission of Ross River virus (RRv) infection, and to assess the difference in the potential predictors of RRv incidence in coastline and inland regions, Queensland, Australia.

Methods: Information on the RRv cases notified between 1985 to 1996 was obtained from the Queensland Department of Health. Climate and population data were supplied by the Australian Bureau of Meteorology and the Australia Bureau of Statistics, respectively. The function of cross correlations was used to compute a series of correlations between climate variables (rainfall, maximum temperature, minimum temperature, relative humidity, and high tide) and the monthly incidence of RRv disease over a range of time lags. Time series Poisson regression models were performed to adjust for the autocorrelations of the monthly incidences of RRv disease and the confounding effects of seasonality, the case notification time, and population sizes.

Results: The cross correlation function shows rainfall, maximum temperature, minimum temperature, and relative humidity at a lag of 1–2 months and high tide in the current month were significantly associated with the monthly incidence of RRv in the coastline region. Relative humidity and rainfall at a lag of two months was also significantly associated with the monthly incidence of RRv in the inland region. The results of Poisson regressive models show that the incidence of RRv disease was significantly associated with rainfall, maximum temperature, minimum temperature, relative humidity, and high tide in the coastline region, and with rainfall and relative humidity in the inland region. There was a significant interaction between climate variables and locality in RRv transmission.

Conclusions: Climate variability may have played a significant role in the transmission of RRv. There appeared to be different responses of RRv to climate variability between coastline and inland cities in Queensland, Australia. Maximum temperature appeared to exhibit a greater impact on the RRv transmission in coastline than in inland cities. Minimum temperature and relative humidity at 3 pm inland seemed to affect the RRv transmission more than at the coastline. However, the relation between climate variables and RRv needs to be viewed within a wider context of other social and environmental factors, and further research is needed.

     

国家人体生物监测项目抽样方法及误差估计

目的 探讨国家人体生物监测项目抽样方法,并通过计算抽样误差来评估抽样设计。方法 该监测采用多阶段复杂抽样方法,并以贵州省抽样结果为例,应用多阶段不等概率抽样误差计算方法计算贵州省抽样误差及变异系数,探讨多阶段抽样设计下误差估计方法。结果 该监测覆盖全国31个省（自治区、直辖市）的152个监测点,抽取21 888名3~79岁城乡居民,三个阶段置换率分别为5.26%、6.35%及40.6%。经计算贵州省抽样误差为3 207 594人,变异系数为0.097。结论 根据多阶段不等概率抽样方法计算,贵州省抽样变异系数较小,精度较高,但该计算方法未考虑人群缺失率、应答率等非抽样误差的权重调整,大型公共卫生监测项目多阶段抽样误差计算方法有待继续研究。     

Monocyte-derived extracellular trap (MET) formation induces aggregation and affects motility of human spermatozoa in vitro

ABSTRACT

The presence of bacteria and/or leukocytes can alter semen quality resulting in low sperm quality and infertility. Inflammation or infection increases the numbers of PMN or macrophages/monocytes in male genital tract. Release of extracellular traps (ETs) by leukocytes has been recognized as a novel mechanism of early host innate immunity, in response to invasive pathogens. This is the first work that evaluated the mechanism of triggered ETs in monocytes co-incubated with spermatozoa or bacteria and the effect on sperm function. Selected spermatozoa and human monocytes isolated from peripheral blood were obtained by healthy donors. Two experimental models were developed, one aseptic (non-infectious) incubating spermatozoa and monocytes, and septic models (infectious) incubating spermatozoa with monocytes and uropathogenic Escherichia coli (E. coli). ETs of monocytes (METs) (DNA, global histone and citrullinated histones) were visualized by scanning electron microscopy (SEM) and immunofluorescence analyses. Progressive motility was performed at 0, 10, 30, 60, and 180 min after co-incubation with CASA system. SEM- and immunofluorescence-analyses revealed human spermatozoa alone or in the presence of E. coli as strong inducers METs. In aseptic model, the motility decreased to 65.2 ± 3.5% at 10 min of incubation and 29.3 ± 3.3% at 30 min (p < 0.001). In septic model, motility decreased to 44.5 ± 5.9% (10 min) and 12.7 ± 2.2% (30 min) (p < 0.001). MET-derived small spermatozoa aggregations were observed in both models. METs might physically block spermatozoa and decrease motility after a brief contact. This may impair male fertility, especially in patients with genital tract infections or chronic inflammation.

Abbreviations: PMN: polymorphonuclear; ETs: extracellular traps; E. coli: Escherichia coli; METs: ETs of monocytes; SEM: scanning electron microscopy; NE: neutrophil elastase; MPO: myeloperoxidase; MAGI: male accessory gland infection; PBMC: peripheral blood mononuclear cells; RT: room temperature; CFU: colony forming units; CASA: computer-aided sperm analysis; H4Cit3: histone H4 citrullinated 3     

Antimicrobial activity of selected synbiotics targeted for the elderly against pathogenic Escherichia coli strains

The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.