Human Enteric α-Defensin 5 Promotes Shigella Infection by Enhancing Bacterial Adhesion and Invasion.

Shigella is a Gram-negative bacterium that causes bacillary dysentery worldwide. It invades the intestinal epithelium to elicit intense inflammation and tissue damage, yet the underlying mechanisms of its host selectivity and low infectious inoculum remain perplexing. Here, we report that Shigella co-opts human α-defensin 5 (HD5), a host defense peptide important for intestinal homeostasis and innate immunity, to enhance its adhesion to and invasion of mucosal tissues. HD5 promoted Shigella infection in vitro in a structure-dependent manner. Shigella, commonly devoid of an effective host-adhesion apparatus, preferentially targeted HD5 to augment its ability to colonize the intestinal epithelium through interactions with multiple bacterial membrane proteins. HD5 exacerbated infectivity and Shigella-induced pathology in a culture of human colorectal tissues and three animal models. Our findings illuminate how Shigella exploits innate immunity by turning HD5 into a virulence factor for infection, unveiling a mechanism of action for this highly proficient human pathogen.

A human pathogenic bacterium Shigella proliferates in plants through adoption of type III effectors for shigellosis.

Shigella, which infects primates, can be transmitted via fresh vegetables; however, its molecular interactions with plants have not been elucidated. Here, we show that four Shigella strains, Shigella boydii, Shigella sonnei, Shigella flexneri 2a, and S. flexneri 5a, proliferate at different levels in Arabidopsis thaliana. Microscopic studies revealed that these bacteria were present inside leaves and damaged plant cells. Green fluorescent protein (GFP)-tagged S. boydii and S. flexneri 5a colonized leaves only, whereas S. flexneri 2a colonized both leaves and roots. Using Shigella mutants lacking type III secretion systems (T3SSs), we found that T3SSs that regulate the pathogenesis of shigellosis in humans also play a central role in bacterial proliferation in Arabidopsis. Strikingly, the immunosuppressive activity of two T3S effectors, OspF and OspG, was required for proliferation of Shigella in Arabidopsis. Of note, delivery of OspF or OspG effectors inside plant cells upon Shigella inoculation was confirmed using a split GFP system. These findings demonstrate that the human pathogen Shigella can proliferate in plants by adapting immunosuppressive machinery used in the original host human.

Occurrence of enteropathogenic bacteria in birds of prey in Italy.

The importance of wild birds as potential vectors of disease has received recent renewed empirical interest, especially regarding human health although information regarding the enteropathogenic bacteria in birds of prey continue to be scant. This study was performed with the aim to evaluate the occurrence of enteropathogenic bacteria (i.e. Campylobacter spp. Escherichia coli, Salmonella spp.) in birds of prey carcasses in Southern Italy. The results of the present study showed a prevalence of 33·1% (49/148) for Campylobacter spp. where all positive isolates (49/49) were identified as Campylobacter jejuni, and among these positive 12/49 were also identified as Campylobacter coli. Thus, 12/49 birds of prey showed mixed infections for both Campylobacter species. Differences in Campylobacter spp. prevalence between diurnal and nocturnal birds were statistically significant (P = 0·016). Escherichia coli showed a prevalence of 6·8% (10/148) and were serogrouped as O26 (n = 3), O55 (n = 2), O145 (n = 5). Salmonella spp. showed a prevalence of 6·8% (10/148) and were serotyped as S. Napoli (n = 4), Salmonella salamae (n = 3) and S. Typhimurium (n = 3). Although wildlife disease outbreaks have often been underreported in the broader context of global epidemiology, results of the present study suggest that birds of prey may serve as a reservoir of pathogens for livestock and human health, acting at the animal-human-ecosystem interface. SIGNIFICANCE AND IMPACT OF THE STUDY: This study confirms the role of birds of prey as a reservoir of enteropathogenic bacteria (i.e. Campylobacter spp., Escherichia coli, Salmonella spp.). Wild birds can contaminate environment with their faeces and play a crucial role in the transmission of pathogens to poultry and livestock farms and aquifers supplying water to humans. Furthermore, wild birds could disseminate pathogens within rescue and rehabilitation centres where they are admitted.

Study of enteropathogenic bacteria in children with acute diarrhoea aged from 7 to 10 years in Xuzhou, China.

BACKGROUND: Acute diarrhoea is a common infectious disease among children in many countries and it has different kinds of clinical symptoms including vomiting, abdominal cramps, or fever of 38 °C. Some specific intestinal bacteria and their quantities can result in relevant symptoms. AIM: To analyze the correspondence between enteropathogenic bacteria and acute diarrhoea at family-level using high-throughput sequencing approach. METHODS: Every 30 children of acute diarrhoea with abdominal cramps, vomiting, and fever of 38 °C was regarded as a group, respectively. Stools samples were collected from each group and the DNA of stool was examined by E.Z.N.A.(®) Stool DNA Kit. The 16S rRNA genes sequencing was performed on an Illumina Miseq platform. FINDINGS: The sequencing dataset comprised 65,092 valid reads sequences that affiliated to the 18 phylogenetic families. The four dominant taxonomic groups in all three samples were Streptococcaceae, Veillonellaceae, Enterobacteriaceae and Lactobacillaceae. The stools of children with high fever presented higher pathogenic bacterial diversities and more complex community structures than other two groups. Lactobacillaceae was the enteric predominant microflora that could reduce the severity of acute diarrhoea. CONCLUSION: The reduction of predominant microflora or the aberrant proliferation of sub-dominant microflora can break the intestinal operation mechanism and cause intestinal diseases. What's more, people's living habits are also correlative about acute diarrhoea and parents should prepare light food for their children in order to protect their tender gastrointestinal mucosa.

Separation and Identification of Four New Compounds with Antibacterial Activity from Portulaca oleracea L.

The Portulaca oleracea L. (P. oleracea) has been used to treat bacillary dysentery for thousands of years in China. Pharmacology studies on P. oleracea have also showed its significant antibacterial effects on the enteropathogenic bacteria, which might reveal the treatment of P. oleracea in cases of bacillary dysentery to some extent. To date, however, the therapeutic basis of P. oleracea treating on bacillary dysentery remains unknown. We determined the antibacterial effective fraction of P. oleracea in a previous study. The current study, which is based on our previous study, was first designed to isolate, identify and screen antibacterial active constituents from P. oleracea. As a result, four new compounds (1-4), portulacerebroside B (1), portulacerebroside C (2), portulacerebroside D (3) and portulaceramide A (4) along with five known compounds (5-9) were isolated, and structures were established by their physico-chemical constants and spectroscopic analysis. The antibacterial activities against common enteropathogenic bacteria were evaluated for all compounds and the new compounds 1-4 showed significant antibacterial effect on enteropathogenic bacteria in vitro, which might contribute to revealing the treatment of P. oleracea in cases of bacillary dysentery.

Novel Insights into the Interaction between Enteropathogenic Bacteria, Pyroptosis and IBD.

Inflammatory bowel disease (IBD) is a chronic and recurrent inflammatory disease of the intestinal tract. The complex pathophysiological mechanisms of IBD include genetic susceptibility, environmental factors, and abnormal immune response of the gut microbiota. Gut microbiota forms a metabolic organ that contributes to human health by performing various physiological functions. The development of IBD is closely linked to the imbalance of gut microbiota. In IBD patients, this imbalance is mainly characterized by an increased abundance of pro-inflammatory microorganisms, specifically enteropathogenic bacteria. Pyroptosis is a form of programmed cell death that can be initiated by microbial infection or host factors. It occurs mostly after intracellular infection with bacteria or pathogens. Other than cell death, its primary effect is to release inflammatory mediators that trigger an inflammatory response in the host. Pyroptosis is an important component of innate immunity and can protect against intracellular risk factors via the inflammatory response. However, excessive activation can cause disease. Previous studies of IBD have indicated a complex relationship between gut microbiota and pyroptosis. Some enteropathogenic bacteria can activate the host's immune system to clear infected cells. This inhibits the proliferation of enteropathogenic bacteria by inducing pyroptosis and restoring the balance of gut microbiota. However, the initial inflammatory response and damage to the integrity of the intestinal barrier are crucial factors that elicit the onset of IBD and favor its progression. This review summarizes research on the role of several common enteropathogenic bacteria in the development of IBD through their induction of host cell pyroptosis. A better understanding of the complex interactions between gut microbiota and pyroptosis should lead to the identification of new targets and treatment options for IBD.

Impact of COVID-19 Restrictions on Incidence of Enteropathogenic Bacteria, Virus, and Parasites in Denmark: A National, Register-Based Study.

Diarrheal diseases caused by enteric pathogens are a significant public health concern. It is widely considered that close contact between persons, poor hygiene, and consumption of contaminated food are the primary causes of gastroenteritis. Clinical microbiology laboratory observations indicate that the incidence of enteropathogenic microorganisms may have been reduced in Denmark during the COVID-19 pandemic. All Departments of Clinical Microbiology in Denmark provided data on the monthly incidence of Salmonella spp., Escherichia coli, Campylobacter spp., Clostridioides difficile, Norovirus GI+GII, Giardia duodenalis, and Cryptosporidium from March 2018 to February 2021. The data were divided into three periods as follows: Control Period 1 (March 2018 to February 2019); Control Period 2 (March 2019 to February 2020); and the Restriction (pandemic) Period (March 2020 to February 2021). The incidences of pathogenic Salmonella spp.-, Escherichia coli-, and Campylobacter spp.-positive samples decreased by 57.3%, 48.1%, and 32.9%, respectively, during the restriction period. No decrease in C. difficile was observed. Norovirus GI+GII-positive samples decreased by 85.6%. Giardia duodenalis-positive samples decreased by 66.2%. Cryptosporidium species decreased by 59.6%. This study demonstrates a clear decrease in the incidence of enteropathogenic bacteria (except for C. difficile), viruses, and parasites during the SARS-CoV-2 restriction period in Denmark.

Monitoring of enteropathogenic Gram-negative bacteria in wastewater treatment plants: a multimethod approach.

The wastewater treatment processes are associated with the emission of microbial aerosols, including enteropathogenic bacteria. Their presence in this work environment poses a real threat to the health of employees, both through the possibility of direct inhalation of the contaminated air and indirectly through the pollution of all types of surfaces with such bioaerosol particles. This study aimed to investigate the prevalence of enteropathogenic bacteria in the air, on surfaces, and in wastewater samples collected in four wastewater treatment plants (WWTPs). The effectiveness of conventional culture-biochemical, as well as spectrometric and molecular methods for the rapid detection of enteropathogenic bacteria at workstations related to particular stages of wastewater processing, was also evaluated. Bioaerosol, surface swab, and influent and effluent samples were collected from wastewater plants employing mechanical-biological treatment technologies. The air samples were collected using MAS-100 NT impactor placed at a height of 1.5 m above the floor or ground, simulating aspiration from the human breathing zone. Surface samples were collected with sterile swabs from different surfaces (valves, handles, handrails, and coveyor belts) at workplaces. The raw influent and treated effluent wastewater samples were aseptically collected using sterile bottles. The identification of bacterial entheropathogens was simultaneously conducted using a culture-based method supplemented with biochemical (API) tests, mass-spectrometry (MALDI TOF MS), and molecular (multiplex real-time PCR) methods. This study confirmed the common presence of bacterial pathogens (including enteropathogenic and enterotoxigenic Escherichia coli, Salmonella spp., Campylobacter spp., and Yersinia enterocolitica) in all air, surface, and wastewater samples at studied workplaces. Higher concentrations of enteropathogenic bacteria were observed in the air and on surfaces at workplaces where treatment processes were not hermetized. The results of this study underline that identification of enteropathogenic bacteria in WWTPs is of great importance for the correct risk assessment at workplaces. From the analytical point of view, the control of enteropathogenic bacterial air and surface pollution using rapid multiplex-PCR method should be routinely performed as a part of hygienic quality assessment in WWTPs.

Isocaloric diets with varying protein levels affected energy metabolism in young adult Sprague-Dawley rats via modifying the gut microbes: A lipid imbalance was brought on by a diet with a particularly high protein content.

Protein is the most important macro-nutrient when it comes to maximizing health, body composition, muscle growth, and recovery of body tissue. In recent years, it has been found that protein also plays an important role in metabolism and gut microbiota. This study was performed to investigate the effects of an isocaloric diet with different crude protein contents on the energy metabolism of Sprague-Dawley (SD) rats. Results revealed that compared with the 20% crude protein (CP; control) diet, the 38% CP diet improved serum parameters that are associated with dyslipidemia and glucose metabolic disorders in SD rats, whereas the 50% CP diet increased liver injury indicators and fatty acid synthesis-related genes and protein expression in the liver. Compared with the control diet, the 14% CP diet increased the abundance of colonic short-chain fatty acid-producing bacteria (Lachnospiraceae_NK4A136_group and Ruminiclostridium_9) and promoted colonic microbial cysteine and methionine metabolism, the 38% CP diet up-regulated colonic microbial lysine biosynthesis and degradation pathways, and the 50% CP diet down-regulated colonic mucosal cholesterol metabolism. Furthermore, the increase of multiple colonic enteropathogenic bacteria in the 50% CP group was associated with higher palmitic acid and stearic acid concentrations in the colonic microbes and lower cholesterol and arachidonic acid concentrations in the colonic mucosa. These findings revealed that the 14% CP and 38% CP diets improved rats' energy metabolism, while the 50% CP diet was accompanied by lipid metabolism imbalances and an increase in the abundance of multiple enteropathogenic bacteria.

A microfluidic chip-based multiplex PCR-reverse dot blot hybridization technique for rapid detection of enteropathogenic bacteria.

Diarrhea caused by enteropathogenic bacteria is a major public health issue worldwide, especially in developing countries. In this study, a microfluidic chip-based multiplex polymerase chain reaction (PCR)-reverse dot blot hybridization technology for the rapid and simultaneous detection of 11 enteropathogenic bacteria was developed and the entire process was completed within 3-4 h. The specificity of this method was analyzed using 11 types of pure target bacterial colonies and another 7 types of pure bacterial colonies, and its sensitivity was evaluated with the serial 10-fold dilution of 11 types of pure target bacterial colonies. The detection limit of this method was as low as 103-102 CFU/mL, and it exhibited high specificity for enteropathogenic bacteria. A total of 60 clinical diarrheal fecal samples were detected using this method, the results of which were compared with those of the conventional reference method, which resulted in a positive coincident rate of 100% and a negative coincident rate of 93.75%. Based on the findings, it could be concluded that multiplex PCR-reverse dot blot hybridization based on the microfluidic chip is a rapid, economical, sensitive, specific, and high-throughput method for detecting enteropathogenic bacteria.

Molecular mechanisms of multidrug resistance in clinically relevant enteropathogenic bacteria (Review).

Multidrug resistant (MDR) enteropathogenic bacteria are a growing problem within the clinical environment due to their acquired tolerance to a wide range of antibiotics, thus causing severe illnesses and a tremendous economic impact in the healthcare sector. Due to its difficult treatment, knowledge and understanding of the molecular mechanisms that confer this resistance are needed. The aim of the present review is to describe the mechanisms of antibiotic resistance from a genomic perspective observed in bacteria, including naturally acquired resistance. The present review also discusses common pharmacological and alternative treatments used in cases of infection caused by MDR bacteria, thus covering necessary information for the development of novel antimicrobials and adjuvant molecules inhibiting bacterial proliferation.

Non-Digestible Oligosaccharides and Short Chain Fatty Acids as Therapeutic Targets against Enterotoxin-Producing Bacteria and Their Toxins.

Enterotoxin-producing bacteria (EPB) have developed multiple mechanisms to disrupt gut homeostasis, and provoke various pathologies. A major part of bacterial cytotoxicity is attributed to the secretion of virulence factors, including enterotoxins. Depending on their structure and mode of action, enterotoxins intrude the intestinal epithelium causing long-term consequences such as hemorrhagic colitis. Multiple non-digestible oligosaccharides (NDOs), and short chain fatty acids (SCFA), as their metabolites produced by the gut microbiota, interact with enteropathogens and their toxins, which may result in the inhibition of the bacterial pathogenicity. NDOs characterized by diverse structural characteristics, block the pathogenicity of EPB either directly, by inhibiting bacterial adherence and growth, or biofilm formation or indirectly, by promoting gut microbiota. Apart from these abilities, NDOs and SCFA can interact with enterotoxins and reduce their cytotoxicity. These anti-virulent effects mostly rely on their ability to mimic the structure of toxin receptors and thus inhibiting toxin adherence to host cells. This review focuses on the strategies of EPB and related enterotoxins to impair host cell immunity, discusses the anti-pathogenic properties of NDOs and SCFA on EPB functions and provides insight into the potential use of NDOs and SCFA as effective agents to fight against enterotoxins.

Antioxidants, inhibits the growth of foodborne pathogens and reduces nitric oxide activity in LPS-stimulated RAW 264.7 cells of nipa palm vinegar.

Nipa palm vinegar (NPV) made from the sap of nipa palm (Nypa fruticans Wurmb.) has long been used as a local food seasoning and folk medicine. This study compared the bioactive compounds, antioxidant, in vitro anti-inflammatory and antimicrobial activities of three NPVs obtained from different plantations based on varied soil and water salinity levels, including fresh water NPV, brackish water NPV and saline water NPV. The analysis results revealed that total phenolic content of saline water NPV had statistically significantly lower than both fresh water and brackish water NPV (p < 0.0001). Furthermore percentage of acetic acid in brackish water NPV had statistically significantly lower than both fresh water and saline water. NPV (p = 0.002). Nevertheless, total flavonoid and pH, were not significantly different (p = 0.144 and 0.066, respectively). The antioxidant activities using three ABTS, DPPH and FRAP methods displayed similar patterns, in which saline water NPV showed the highest antioxidant activities, followed by brackish water and fresh water NPV, respectively. Antimicrobial activity was examined for seven enteropathogenic bacteria. The tested NPVs were found inhibitive against all test cultures with a minimum inhibitory concentration (MIC) of ≤ 7.8 µL/mL. The cytotoxicity of the NPV obtained from different plantations by MTT assay revealed low cytotoxicity. Anti-inflammatory activity was also carried out through the inhibition of nitric oxide production. The fresh water NPV exhibited the highest anti-inflammatory activity with IC50 17.59 ± 0.17 µL/mL, followed by saline and brackish water NPV with IC50 18.12 ± 0.49 and 28.29 ± 2.64 µL/mL, respectively. The findings indicated that NPV from different soil salinities could potentially be natural functional food and developed to antimicrobial and anti-inflammatory medicinal agents with safety.

Surveillance of enteropathogenic bacteria, protozoa and helminths in travellers returning from the tropics.

Diarrhoea is a frequent symptom associated with travelling to tropical regions, but the cause is often not found. Epidemiology was assessed including up-to-date real-time PCR approaches.We analysed datasets of 528 patients who presented at the Bernhard Nocht Institute for Tropical Medicine in Hamburg, Germany, between 2006 and 2010 for screening purposes or because of diarrhoea. Stool samples were obtained and investigated by microscopy, bacterial culture, two PCR assays targeting Entamoeba histolytica, Entamoeba dispar, Giardia duodenalis, and Cryptosporidium parvum, or Salmonella spp., Shigella/EIEC spp., Campylobacter jejuni, and Yersinia spp.Among patients with gastrointestinal symptoms, 51% tested positive for bacteria or parasites, of which 66% had a known enteropathogenic potential. In patients without diarrhoea, 53% (n = 80) were positive, and 33% of these cases harboured agents of pathogenic potential. Association with clinical symptoms was primarily found for bacterial infections. Blastocystis hominis, however, was more frequent in asymptomatic than in symptomatic travellers.In conclusion, the study stresses the etiological relevance of bacterial gastroenteritis in travellers returning from the tropics, the need for molecular approaches to increase diagnostic sensitivity and demonstrates that asymptomatic carriage of enteropathogens after prolonged stays in the tropics is similarly frequent compared with symptomatic infections in travellers.

The 3-day rule for stool cultures: should all patients with haematological malignancies be excluded?

OBJECTIVES: The '3-day rule' for stool culture ordering suggests that only selected inpatients with nosocomial diarrhoea should have stool cultures for enteropathogenic bacteria (EPBs). Patients with haematological malignancies are not included in this group. We have analysed the ordering of stool cultures at Laikon Hospital to investigate whether all patients with haematological malignancies should be excluded from the 3-day rule. METHODS: We have retrospectively analysed all inpatient stool specimens sent to the microbiology laboratory for enteropathogenic bacteria culture at Laikon Hospital, Athens, Greece, between January 1, 2014 and December 31, 2014. We classified stool cultures sent after the third day as 'appropriate', 'excluded' with standard rule, 'excluded' with haematological malignancies, and 'inappropriate'. RESULTS: During the study period, 1101/1593 inpatient stool cultures (69.1%) had been ordered after the third day of hospitalization. The total yield for inpatient EPB stool cultures was 0.7% (11/1593). The yield for 'appropriate' cultures was significantly higher than the yield of all 'excluded' specimens (3.7% (3/81) versus 0.3% (2/585), p 0.018) and to 'inappropriate' orders (3.7% (3/81) versus 0.0% (0/485), p 0.0028). There was no difference in the yield between specimens 'excluded' with the standard rule and 'excluded' with haematological malignancies. CONCLUSIONS: In our hospital, the yield of stool cultures from patients with haematological malignancies is similar to that of patients 'excluded' from the standard 3-day rule. If patients with haematological malignancies were not excluded from the rule, we would reduce the inpatient stool cultures by 13.6% (217/1593) at the cost of missing one positive stool culture.

Diarrheagenic Escherichia coli and Shigella with High Rate of Extended-Spectrum Beta-Lactamase Production: Two Predominant Etiological Agents of Acute Diarrhea in Shiraz, Iran.

This study was conducted to find the etiology of acute diarrhea in Iranian children and determine the antimicrobial resistance patterns. The pathogenic bacteria were recovered from 110/269 (40.9%) diarrheal fecal samples with the following profiles: the most predominant pathogen was diarrheagenic Escherichia coli (DEC) (43.6%), comprising enteroaggregative E. coli (23.6%), enteropathogenic E. coli (10.9%), enteroinvasive E. coli (5.5%), and enterotoxigenic E. coli (3.6%); Shigella spp. (37.3%), Salmonella spp. (12.7%) and Campylobacter jejuni (6.4%) were ranked second and fourth in terms of prevalence, respectively. The rates of extended-spectrum beta-lactamase (ESBL) production were 66.7% and 53.7% in DEC and Shigella, respectively. Resistance to ampicillin (AMP) (95.1%), trimethoprim/sulfamethoxazole (SXT) (73.2%), azithromycin (ATH) (21.9%), and ciprofloxacin (CIP) (14.6%) was observed among Shigella isolates. Multidrug resistance phenotype was observed in 24.4% (10/41) of Shigella isolates, with the most common pattern of resistance to cefotaxime, ceftriaxone, ceftazidime, AMP, SXT, and ATH. This study indicates an alarming increase in the ESBL production of DEC and Shigella spp. and identifies them as the two most prevalent diarrhea-causing enteropathogens in the region. The results show that CIP could be an alternative to third-generation cephalosporins against these two pathogens. Therefore, it is proposed that further investigation be done in the pursuit of alternative antibiotics that are effective against the resistant cases. For instance, one study could look into the comparative clinical effectiveness of third-generation cephalosporins versus CIP, the latter not being presently the drug of choice for the treatment of acute diarrhea in children in Iran.

Quantitative microbial risk assessment (QMRA) shows increased public health risk associated with exposure to river water under conditions of riverbed sediment resuspension.

Although higher microbial concentrations have been reported in sediments than in the overlying water column, most quantitative microbial risk assessment (QMRA) studies have not clearly indicated the contribution of sediment-borne pathogens to estimated risks. Thus, the present study aimed at determining the public health risk associated with exposure to pathogenic bacteria in polluted river water under undisturbed conditions and conditions of sediment resuspension in the Apies River, Gauteng, South Africa. Microbial pathogens were isolated and identified using culture and molecular methods. The beta-Poisson dose-response model was used to estimate the probability of infection (Pi) with the various pathogens, following accidental/intentional ingestion of 1mL or 100mL (or 50mL) of untreated river water. Mean wet season Escherichia coli counts ranged between 5.8E+01 and 8.8E+04MPN/100mL (water column) and between 2.40E+03 and 1.28E+05MPN/100mL (sediments). Mean dry season E. coli counts ranged between 5.11E+00 and 3.40E+03MPN/100mL (water column) and between 5.09E+00 and 6.30E+03MPN/100mL (sediments). Overall (water and sediments) Vibrio cholerae was the most detected pathogen (58.8%) followed by Salmonella spp. (23.9%) and Shigella (10.1%). Ingestion of 1mL of river water could lead to 0%-4% and 1%-74% Pi with E. coli during the dry and wet season, respectively. During the dry season, the Pi with V. cholerae, Salmonella spp. and Shigella spp. were 0%-1.39%, 0%-4.11% and 0%-0.16% respectively, depending on volume of water ingested. The risks of infections with all microorganisms increased during the wet season. A 2-log increase in water E. coli count following sediments disturbance led to approximately 10 times higher Pi with E. coli than when sediments were undisturbed. Therefore, the use of the untreated water from the Apies River for drinking, household purposes or recreational activities poses a potential health risk to the users of the river.

Impact of urban contamination of the La Paz River basin on thermotolerant coliform density and occurrence of multiple antibiotic resistant enteric pathogens in river water, irrigated soil and fresh vegetables.

La Paz River in Andean highlands is heavily polluted with urban run-off and further contaminates agricultural lowlands and downstream waters at the Amazon watershed. Agricultural produce at this region is the main source of vegetables for the major Andean cities of La Paz and El Alto. We conducted a 1 year study, to evaluate microbial quality parameters and occurrence of multiple enteropathogenic bacteria (Enterohemorrhagic E. coli-EHEC, Enteroinvasive E. coli or Shigella-EIEC/Shigella, Enteroaggregative E. coli-EAEC, Enteropathogenic E. coli-EPEC Enterotoxigenic E. coli-ETEC and Salmonella) and its resistance to 11 antibiotics. Four sampling locations were selected: a fresh mountain water reservoir (un-impacted, site 1) and downstream sites receiving wastewater discharges (impacted, sites 2-4). River water (sites 1-4, N = 48), and soil and vegetable samples (site 3, N = 24) were collected during dry (April-September) and rainy seasons (October-March). Throughout the study, thermotolerant coliform density values at impacted sites greatly exceeded the guidelines for recreational and agricultural water uses. Seasonal differences were found for thermotolerant coliform density during dry season in water samples nearby a populated and hospital compound area. In contrast to the un-impacted site, where none of the tested enteropathogens were found, 100 % of surface water, 83 % of soil and 67 % of vegetable samples at impacted sites, were contaminated with at least one enteropathogen, being ETEC and Salmonella the most frequently found. ETEC isolates displayed different patterns of toxin genes among sites. The occurrence of enteropathogens was associated with the thermotolerant coliform density. At impacted sites, multiple enteropathogens were frequently found during rainy season. Among isolated enteropathogens, 50 % were resistant to at least two antibiotics, with resistance to ampicillin, nalidixic acid, trimethoprim-sulfamethoxazole and tetracycline commonly present. Moreover, some Salmonella isolates were distinguished by their multi-resistance to ≥8 antibiotics, within soil and vegetable samples. Overall, this study demonstrates that La Paz River-an affluent of the Amazon macrobasin-is heavily polluted along the year with a high density of thermotolerant coliforms and is a reservoir of multiple antibiotic resistant enteropathogens, present in river water, soil and vegetables. These data highlight health risk associated with food and waterborne diseases at the region.

Antagonistic activity of probiotic lactobacilli against human enteropathogenic bacteria in homemade tvorog curd cheese from Azerbaijan.

INTRODUCTION: Human health is deemed to be maintained by the crosstalk among the body and probiotic bacteria. Disruptions in this composition are associated with the pathogenesis of numerous diseases. Through modernization, traditional foods consumption has been abandoned and native food starters have been substituted with industrial products. Hence, we aimed to isolate and evaluate probiotic bacteria from traditional fermented foods which can be used as probiotics as well as starter cultures in food industry and in medicine against antibiotic resistant pathogenes. To this end, an intact village was recognized in the Republic of Azerbaijan with traditional dairy products, yielding a variety of potential probiotics. METHODS: In this study, tvorog as a traditional dairy product from Dashkasan, Ismailli and khachmaz regions in Azerbaijan was characterized for the isolation of Lactobacilli with probiotic potentiality. The bacteria were tested for the resistance to the acid, bile, and the antagonistic effect of human pathogenic bacteria. The isolates were identified by 16s rDNA sequencing with a blast to the databank. RESULTS: Three species with higher homology to the L. planetarium, L. rhamnosus, and L. casei with high probiotic potentiality and antibacterial effects were isolated. CONCLUSION: Homemade tvorog curd cheese in Azerbaijan harbor a variety of probiotics with industrial applications as well as potentiality to be preserved in a biobank for the future medicinal applications especially against antibiotic resistant pathogenes.

Prevalence of enteropathogenic bacteria in treated effluents and receiving water bodies and their potential health risks.

The failure of wastewater treatment plants to produce effluents of a high microbiological quality is a matter of great concern in terms of water resource pollution. A more serious concern is that this water source is used by communities in developing countries for multiple purposes, which include drinking, recreation and agriculture. The current study investigated the prevalence and potential health risks of enteropathogenic bacteria (Salmonella typhimurium, Shigella dysenteriae and Vibrio cholerae) in the treated effluents of three selected South African Wastewater Treatment Works as well as their receiving water bodies. Culture-based and polymerase chain reaction techniques were used to detect and identify the pathogenic bacteria. The conventional methods revealed that of the 272 water samples collected, 236 samples (86.8%) tested presumptively positive for Salmonella spp., 220 samples (80.9%) for Shigella spp. and 253 samples (93.0%) for V. cholerae. Molecular test results indicated that out of the randomly selected presumptive positive samples (145), zero to 60% of samples were positive for S. typhimurium and S. dysenteriae and 20% to 60% for V. cholerae. For the health risk assessment, the daily combined risk of S. typhimurium, S. dysenteriae and V. cholerae infection was above the lowest acceptable risk limit of 10(-4) as estimated by the World Health Organization for drinking water. This study showed that the target treated wastewater effluents and their receiving water bodies could pose a potential health risk to the surrounding communities.