Fecal Bacteria Concentrations Research Articles

Detection and modeling of Staphylococcus aureus and fecal bacteria in Hawaiian coastal waters and sands.

Microbial pollution of recreational waters leads to millions of skin, respiratory, and gastrointestinal illnesses globally. Fecal indicator bacteria (FIB) are monitored to assess recreational waters but may not reflect the presence of Staphylococcus aureus, a global leader in bacterial fatalities. Since many community-acquired S. aureus skin infections are associated with high recreational water usage, this study measured and modeled S. aureus, methicillin-resistant S. aureus (MRSA), and FIB (Enterococcus spp., Clostridium perfringens) concentrations in seawater and sand at six beaches in Hilo, Hawai'i, USA, over 37 sample dates from July 2016 to February 2019 using culturing techniques. Generalized linear models predicted bacterial concentrations with physicochemical and environmental data. Beach visitors were also surveyed on their preferred activities. S. aureus and FIB concentrations were roughly 6-78 times higher at beaches with freshwater discharge than at those without. Seawater concentrations of Enterococcus spp. were positively associated with MRSA but not S. aureus. Elevated S. aureus was associated with lower tidal heights, higher freshwater discharge, onsite sewage disposal system density, and turbidity. Regular monitoring of beaches with freshwater input, utilizing real-time water quality measurements with robust modeling techniques, and raising awareness among recreational water users may mitigate exposure to S. aureus, MRSA, and FIB. PRACTITIONER POINTS: Staphylococcus aureus and fecal bacteria concentrations were higher in seawater and sand at beaches with freshwater discharge. In seawater, Enterococcus spp. positively correlated with MRSA, but not S. aureus. Freshwater discharge, OSDS density, water turbidity, and tides significantly predicted bacterial concentrations in seawater and sand. Predictive bacterial models based upon physicochemical and environmental data developed in this study are readily available for user-friendly application.

Assessing viability of Escherichia coli in mining-impacted surface waters

Multiple threats to surface water quality, including both fecal pollution and acid mine drainage (AMD) are frequently coincident in mining regions, such as parts of the Appalachian region of the U.S. While it has been established that AMD can have toxic effects to fecal bacteria in surface waters, there is also evidence that AMD may induce a viable but non-culturable (VBNC) state, leaving fecal bacteria undetectable by common standard methods. This study aims to better understand the occurrence of VBNC Escherichia coli in mining-impacted waters (MIW) through three objectives: (1) assess the relationship between MIWs and concentrations of culturable fecal bacteria, (2) compare standard methods for quantification of E. coli in MIW, and (3) investigate whether MIW can induce a VBNC state in E. coli. An analysis of historic data from the Deckers Creek and West Run Watersheds of West Virginia revealed a moderate correlation between pH and E. coli abundance determined via culture and enzyme-based methods. In samples collected from sites within the two watersheds impacted by historic mining activities, the E. coli uidA gene was measured via quantitative polymerase chain reaction (qPCR) and found to be significantly more abundant than E. coli concentrations measured via culture or enzyme substrate coliform test. However, this discrepancy between methods was greatest in samples with a low pH. Further, experiments in which an environmental strain of E. coli was dosed into samples of MIW diluted with saline at different concentrations confirmed that the culturability of E. coli significantly decreased with increasing MIW concentration, while the total number of intact cells, determined via "live/dead” staining and microscopy, remained high. This finding suggests that culture and enzyme methods may underestimate viable E. coli levels in AMD-impacted waters.

Environmental variables and its association with faecal coliform at Madh Island beaches of megacity Mumbai, India

The abundance of fecal-indicating bacteria in water bodies are said to be influenced by environmental conditions. The effect of environmental parameters on the changing microbial population plays an important role in coastal water quality assessment. It's crucial to comprehend these patterns in order to support management initiatives for pollution control. There are studies on faecal bacteria contamination of surface water and how environmental conditions affect it, however majority of them are based on large river basins and temperate regions of developed countries. In this paper, we study the different physicochemical and physical factors of the five recreational beaches in Mumbai, India and examine how these environmental factors affect the levels of faecal indicating bacteria, namely, coliforms in the region. A relatively high number of coliform was identified from the water and sediment samples of Marve Beach (>1600 MP N/100 ml or g), followed by Erangal Beach and Danapani Beach (∼150–350 MP N/100 ml or g), exceeding the normal standard limits of <100 MP N/100 ml set by the Central Pollution Control Board (CPCB) of India. Of the physiochemical parameters examined, BOD showed to have a strong positive correlation with the coliform bacteria. The nutrients and heavy metal concentrations did not show any major effect on the microbial population. The MIKE CMAP predicted tide, MIKE3 Flow Model FM simulated coastal current, ERA5 hourly wind, as well as SWAN model simulated nearshore wave together considerably exhibit alliance of microbial behavior in the beaches with ambient physical processes. This study reveals that Mumbai's coastal water contain significant concentrations of faecal bacteria, which, if not monitored regularly could have future consequences on the recreational activities of the region, thereby on public health. This assessment might help in simulation of water quality prediction, and for optimizing the coastal zone management and development across recreational beaches.

Model-based prediction of bathing water quality in a lake polluted by fecal coliform bacteria from combined sewer overflows

In the European Union, recreational water quality is regulated by the bathing water directive, which requires authorities to regularly take water samples to identify fecal bacterial pollution, which can compromise the bathing water quality at designated recreational bathing water areas. Using a case study from Lake Knudsøin Denmark, this paper shows that the bathing water quality occasionally is compromised by overflows from combined sewer systems. Due to the randomness in the frequency of overflow occurrences, the entailing decrease in bathing water quality is not normally detected by the regulatory sampling campaigns. By dedicated sampling campaigns conducted in this project in the proximity of outlets and recreational bathing areas and by hydrodynamical transport modeling, it is shown that the transport patterns of pollutants are crucially and rapidly dependent on dynamic conditions. The occasional short-term pollution by fecal bacteria and consequent decrease in bathing water quality are, therefore, challenging to capture (both spatially and temporally) by regular water sampling. Rather than increasing the frequency of water sampling, an online model-based warning system for fecal bacteria contamination in bathing areas is proposed. This warning system framework includes: (1) dynamical modeling of combined sewer overflow based on rainfall over a catchment area, (2) a hydrodynamical model that simulates current fields in multiple vertical layers based on wind forcing and water fluxes, and (3) a particle dispersion model which provides an estimate of pollutant concentrations. The output from the model has shown potential to issue bathing prohibition if there is a risk of fecal bacteria concentrations below the criteria for good bathing water quality.

Prairie strips reduce fecal indicator bacteria concentrations in simulated runoff

AbstractVegetative filter strips (VFS) have shown promising results in reducing the downstream transport of many agroecosystem contaminants. A recently developed type of VFS, prairie strips, has been shown to significantly reduce the impact of corn and soybean production systems on water quality in terms of sediment, nitrogen, and phosphorus losses. This study assessed potential additional benefits of prairie strips to include the reduction of pathogens. To assess the impact of prairie strips on manure‐laden agricultural runoff, we utilized a physical model of prairie strips in a laboratory flume to conduct highly controlled overland flow experiments. Escherichia coli and Enterococcus concentration reductions of up to 45% and 65% were observed for runoff and infiltration flows, respectively, while mass load reductions of up to 65% were observed for surficial runoff flows. The degree of concentration or mass load reductions was dependent on the residence time of the flow within the strip and the partitioning of overland flow running onto the strip to infiltration and runoff flows. Based on our results and a review of the literature, we developed a design method to provide guidance on the width of prairie strip buffer needed to achieve a user‐defined reduction of fecal bacteria concentration.

Two-year monitoring of enterovirus and rotavirus A in recreational freshwater from an island region, Pará State, northern Brazil

Enteric viruses are major causes of waterborne diseases and are present in large quantities in the stools of infected individuals. Its viability in the environment lasts for months, favoring the contamination of water used for consumption and recreation. The study aimed to monitor monthly the circulation of enterovirus (EV) and group A rotavirus (RVA) in recreational freshwater from an island region used as a bathhouse in northern Brazil, from January 2012 to December 2013. The viral RNA was obtained using guanidine isothiocyanate/silica after viral concentration by adsorption-elution method. The molecular detection was carried out by semi (EV) and nested-PCR (RVA) and the amplicons were sequenced on automated sequencer. At least one of these viruses was detected on 40.4% (42/104) of the samples. RVA was the most frequent (n = 32; 30.8%) when compared to EV (n = 20; 19.2%). Co-circulation between both was identified in 9.6% (n = 10). The highest viral positivity was found in SP02 (46.1%). The highest viral positivity was observed during high tides (57.7%; 60/104). Most EV samples were characterized as coxsackievirus (CV) A5 (85.7%, 12/14) and others as Sabin 1 poliovirus (14.2%, 2/14). The RVA positive samples were genotyped as G2, G3, G9, G12, P[8], P[4], and P[6]. These viruses were detected in 35.6% (37/104) of the samples with an acceptable concentration of fecal coliform bacteria. These results demonstrate the contamination of surface water intended for recreation by enteric viruses of Public Health concern even when bacterial indicators are within the tolerated limit, a factor that confirms the need for public policies aimed the sewage treatment before its release into water bodies.

Escherichia coli and Enterococci Bacteria in Lake Michigan Beach Sand

Fecal indicator bacteria can be used as a surrogate to pathogenic microorganisms to monitor fecal contamination in water bodies. Increased concentrations of fecal bacteria may pose public health ri...

Staphylococci and fecal bacteria as bioaerosol components in animal housing facilities in the Zoological Garden in Chorz\xf3w

Zoos are places open for a large number of visitors, adults and children, who can admire exotic as well as indigenous animal species. The premises for animals may contain pathogenic microbes, including those exhibiting antibiotic resistance. It poses a threat to people remaining within the zoo premises, both for animal keepers who meet animals on a daily basis and visitors who infrequently have contact with animals. There are almost no studies concerning the presence on the concentration of airborne bacteria, especially staphylococci and fecal bacteria in animal shelters in the zoo. There is no data about antibiotic resistance of staphylococci in these places. The results will enable to determine the scale of the threat that indicator bacteria from the bioaerosol pose to human health within zoo premises. This study conducted in rooms for 5 animals group (giraffes, camels, elephants, kangaroos, and Colobinae (species of monkey)) in the Silesian Zoological Garden in Chorzów (Poland). The bioaerosol samples were collected using a six-stage Andersen cascade impactor to assess the concentrations and size distribution of airborne bacteria. Staphylococci were isolated from bioaerosol and tested for antibiotic resistance. In our study, the highest contamination of staphylococci and fecal bacteria was recorded in rooms for camels and elephants, and the lowest in rooms for Colobinae. At least 2/3 of bacteria in bioaerosol constituted respirable fraction that migrates into the lower respiratory tract of the people. In investigated animal rooms, the greatest bacteria contribution was recorded for bioaerosol fraction sized 1.1–3.3μm. Bacterial concentrations were particularly strong in spring and autumn, what is related to shedding fur by animals. Among the isolated staphylococci which most often occurred were Staphylococcus succinus, S. sciuri, and S. vitulinus. The highest antibiotic resistance was noted in the case of Staphylococcus epidermidis, while the lowest for S. xylosus. In addition to standard cleaning of animal rooms, periodic disinfection should be considered. Cleaning should be carried out wet, which should reduce dust, and thus the concentrations of bacteria in the air of animal enclosures.

Wastewater Discharge through a Stream into a Mediterranean Ramsar Wetland: Evaluation and Proposal of a Nature-Based Treatment System

Impacts on wetlands are becoming more pressing every day. Among them, habitat loss, overexploitation of aquifers and changes in land use are considered the most important. However, the impacts linked to wastewater discharges are increasing worldwide. In this context, this study analyses the impacts of input of wastewater to a Mediterranean Ramsar temporary wetland (Fuente de Piedra, south of Spain). To this end, systematic sampling was carried out in the Charcón stream which receives water from a wastewater treatment plant (WWTP) and discharges it into the wetland. The results showed a slight decrease in the nutrient concentrations, particularly for nitrogen compounds. Heterotrophic and fecal bacteria concentration, as well as phytoplankton and zooplankton abundance and biomass, all significantly decreased from the treatment plant to the wetland. When comparing the effect of this discharge with other similar occurring to the same wetland, it was evident that the Charcón stream was responsible for a greater impact. At this point, it is relevant to note that the main difference among both treated wastewater discharges lies in the different water retention time once the wastewater was released from the WWTP. In fact, we recommend an increase in the water retention time by building seminatural ponds, together with the use of biofilters, which will notably contribute to improve the processes of assimilation of nutrients and to decrease the impact generated in the wetland by this spill.

Performance of sludge degradation, mineralization and electro-energy harvesting in a sludge treatment electro-wetland: Insight into the sludge loading rate

In order to enhance the performance of sludge treatment wetland (STW), microbial electrochemical system (MES) was introduced into a conventional sludge treatment wetland. A sludge treatment electro-wetland (STEW) was specially developed and investigated for its performance in sludge treatment and bioenergy production. The study investigated the performance of the STEW in terms of sludge organic degradability, sludge stabilization and the capability of bioelectricity generation at different sludge loading rates (SLR) of 50, 95, 125 kg TS/year·m2. The quality of the final residual sludge product for agricultural reuse was also characterized. Results revealed that the highest power output (0.790 V of voltage and 0.229 W/m3 of power density) of STEW was achieved with the highest SLR (125 kg TS/year·m2). The best sludge treatment efficiency (7.07 % of dewatering rate, 40.43 % of volatile solid (VS) removal and 80.95 % of total chemical oxygen demand (TCOD) removal) of STEW were achieved with proper SLR of 95 kg TS/year·m2. After resting period, the nutrient concentrations in the residual sludge were quite low (total nitrogen of 2.86 % total solid (TS) and total phosphorous of 0.93 %TS), and heavy metals and faecal bacteria (Salmonella spp. and Escherichia coli) concentrations remained within the current legal limits for land application of the sludge. Experiments showed that the STEW system demonstrated a satisfactory efficiency for sludge dewatering and mineralization in spite of the high sludge loading rate and recycled the bioenergy simultaneously. The results also illustrated that the STEW was a promising technology for simultaneous sludge treatment and energy recovery.

Spread Patterns of Antibiotic Resistance in Faecal Indicator Bacteria Contaminating an Urbanized Section of the Brda River

This paper presents the spatio-temporal distribution of faecal indicator bacteria (FIB) in the river section subject to anthropogenic stress and describes spread patterns of antibiotic resistance in the studied bacterial groups. The analysis involved 58 strains of Escherichia coli and 61 strains of enterococci. Antibiotic resistance profiles were prepared in accordance with the recommendations of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The results indicated a correlation between the location of a sampling site and the concentration of faecal bacteria. The highest average concentrations were recorded at the site located in the city centre, where the river is used mainly for recreation. Antibiotic resistance profiles showed that Escherichia coli had 100% sensitivity to tigecycline, levofloxacin and imipenem. The highest percentaage of strains (17%) were resistant to piperacillin. Enterococci were 100% sensitive to levofloxacin. No strains were vancomycin-resistant (VRE). The highest percentage of strains was resistant to imipenem (23%), and the lowest, to ampicillin (2%). The spatio-temporal distribution of antibiotic-resistant strains (ARS) indicated a high concentration of drug-resistant Escherichia coli (47%) in the summer season at the sampling site located in the last part of the river. At the same time, drug resistance in enterococci increased along the river course and was considerably higher in spring. There were no significant relationships between physico-chemical parameters of water and the levels of faecal bacteria. On the other hand, strong relationships were observed between the percentage of strains showing resistance to the applied antibiotics and physico-chemical and biological parameters of water. The percentage of antibiotic resistant strains of Escherichia coli was negatively correlated with dissolved oxygen concentration (r = − 0.9; p < 0.001) and BOD5 (r = − 0.85; p < 0.05). The percentage of antibiotic resistant strains of enterococci was most strongly correlated with water pH (r = − 0.92; p < 0.001).

Stable nitrogen isotopes in octocorals as an indicator of water quality decline from the northwestern region of Cuba.

Eutrophication is one of the causes of the degradation of reefs worldwide. The aim of this research is to determine if sewage discharge reaches the fore reefs at northwest of Cuba using δ15N in tissues of the octocorals Eunicea flexuosa and Plexaura kuekenthali and the concentration of microbiological and physical-chemical variables. Thirteen reefs at 10-m depth were selected near river basins and far from the urban and industrial development of Havana City. Branch tips of both species were collected, the concentrations of nutrient and microorganisms in water samples were quantified, and horizontal visibility in the water (Vis) was determined. Overall, δ15N of E. flexuosa ranged from 1.5 to 6.3‰ and P. kuekenthali from 1.7 to 6.7‰. The tissue of both species was significantly enriched in 15N in reefs near polluted watersheds compared with reefs far from pollution by anthropogenic activities. The δ15N of both species showed a positive and significant correlation with the concentration of fecal and total coliform bacteria, heterotrophic bacteria, and NH4+ and a negative and significant correlation with the Vis. The δ15N of the two species and microbiological and physical-chemical variables evidenced water quality decline by sewage discharge that reached reefs near polluted watersheds.

Apple polysaccharide could promote the growth of Bifidobacterium longum

It is widely accepted that regulating microbiome could improve human health. We previously observed apple polysaccharide (AP) reversed high-fat-induced microbial dysbiosis, but the mechanism remains to be elucidated.In this study, the function of AP in vitro was evaluated in Bifidobacterium longum (B. longum) and Lactobacillus rhamnosus (L. rhamnosus). The effects of AP on the composition of fecal bacteria of normal SD rats were investigated by qPCR, TA cloning and 16S sequencing. 0.125–2% AP showed no significant effect on the growth of B. longum and L. rhamnosus. DNA concentration of fecal bacteria cultured with 1% AP was significantly higher than that of control group. qPCR revealed that the number of Bifidobacterium and Lactobacillus in fecal flora incubated by 1% AP was significantly higher than that of control group. Three strains of escherichia coli (E. coli) in fecal bacteria were screened out and analyzed. AP can be utilized by one E. coli and the metabolic products of AP could enhance the proliferation of B. longum.These data suggest that AP could promote the growth of B. longum indirectly, and provide another basis to understand the health care function of apple.

Combined Domestic and Hospital Wastewaters Treatment by Natural Lagoon System in Tropical Area, Korhogo, Ivory Coast

Wastewaters discharged into surface waters highly impacted humans and living aquatic organisms particularly when the treatment applied to reduce chemical and biological pollution is not appropriated. Biological treatment systems are often applied for the treatment of domestic wastewaters. These systems are limited when applied to the treatment of hospital wastewaters. In this study, we evaluated the efficiency of natural lagoon system, applied to treat combined wastewaters from hospital and from residences of nursing students. Results show that the lagoon system remove 98% of COD, 87% of BOD, 95% of TSS and 92% of total nitrogen. Arsenic and copper are removed (40%), but lead and cadmium concentrations increase in the effluent. Globally, the concentrations of nutrients and heavy metals, in the effluents, are inferiors to the limit values proposed by the Ivorian guidelines for water pollution. However, the reuse of effluents for irrigation of crops likely to be eaten uncooked is not recommended because of the high concentration of fecal bacteria (1.00 x 10⁵ CFU <i>E. coli.</i> 100 mL^-1. The disinfection process must be implemented after biological treatment to ensure the elimination of pathogenic microorganisms present in the effluent and sludge, before their reuse in agriculture.<div><br></div>

Antibiotic Resistance in Enterobacteriaceae from Surface Waters in Urban Brazil Highlights the Risks of Poor Sanitation.

Surface waters are an unappreciated reservoir of antimicrobial resistance (AMR). Poor sanitation brings different species of environmental bacteria into contact, facilitating horizontal gene transfer. To investigate the role of surface waters as potential reservoirs of AMR, we studied the point prevalence of fecal contamination, AMR genes, and Enterobacteriaceae in an urban lake and rural river system in Northeast Brazil in comparison with a lake and sewer system in Northeast Ohio in the United States. Surface water samples were examined for evidence of human fecal contamination using microbial source tracking and screened for plasmid-mediated fluoroquinolone resistance and carbapenemase genes. Enterobacteriaceae were detected using selective agar followed by antimicrobial susceptibility testing and detection of AMR genes by microarray, and classified by repetitive sequence-based polymerase chain reaction and multilocus sequence typing. Concentrations of human fecal bacteria in the Brazilian urban lake and sewage in Northeast Ohio were similarly high. Filtered water samples from the Brazilian urban lake, however, showed the presence of bla OXA-48, bla KPC, bla VIM-2, qnrS, and aac(6')-lb-cr, whereas only bla VIM-2 was identified in raw sewage from Northeast Ohio. From the Brazilian urban lake, 85% of the Enterobacteriaceae (n = 40) cultured were resistant to at least one clinically important antibiotic, including ST131 Escherichia coli harboring the extended-spectrum beta-lactamase CTX-M. Although two isolates demonstrated polymyxin resistance, mcr-1/2 was not detected. Our findings indicate that surface waters in an urban Brazilian site can serve as an environmental reservoir of AMR and that improving wastewater treatment and sanitation generally may ameliorate AMR dissemination.

Wastewater Treatment Potentials of Vegetated Beds with &amp;lt;i&amp;gt;Brillantaisia cf. bauchiensis&amp;lt;/i&amp;gt; Hutch &amp;amp; Dalz and &amp;lt;i&amp;gt;Polygonum salicifolium&amp;lt;/i&amp;gt; Brouss ex Wild in the Western Highlands of Cameroon

The objective of this study was to evaluate the potentials of beds vegetated with medicinal species (Brillantaisia bauchiensis and Polygonum salicifolium) in a constructed wetland for domestic wastewater treatment in the Western Highlands of Cameroon. The study was carried out between March and September 2017 on plants collected from a natural wetland in Penka-Michel. The two plants species selected based on their ethnobotanical importance were transplanted and allowed to grow to maturity in a prepared natural wetland at Penka-Michel and a constructed wetland for domestic wastewater treatment on the campus of the University of Dschang. Growth parameters were followed for the two plants species in both wetlands. The physicochemical parameters and faecal bacteria concentrations were measured only for the vegetated and non-vegetated/control beds in the constructed wetland. Overall, the two plants species showed increased growth in height, diameter, leaf number and plants density. The change in diameter and density were very significantly influenced by species type in the constructed wetland than in the natural wetland. Generally, plant growth in height, diameter and density were higher with B. bauchiensis in the constructed wetland than with P. salicifolium in both wetlands. The mean faecal bacteria removal was higher in the vegetated beds for some bacteria than in the non-vegetated/control bed. There was a significant difference in the reduction efficiency of TSS, turbidity, BOD, Faecal streptococci and Total coliforms bacteria between the inflow and the outflow of some treatment beds especially the bed vegetated with Brillantaisia bauchiensis. There were correlations between the two plants species as concerns increased plants height, diameter, leave number, shoot number and nutrients uptake in the constructed wetland beds compared with the natural wetland.

Bacterial quality evaluation on the shellfish-producing area along the south coast of Korea and suitability for the consumption of shellfish products therein

BackgroundTo confirm whether shellfish are suitable for consumption, the quality of seawater and shellfish in shellfish-producing areas must be assessed regularly. This study was conducted to evaluate the bacterial quality on the Changseon area, containing a designated shellfish-producing area, in Korea during 2011–2013.ResultEven though many inland pollutants near the area were identified, they showed no significant impact on the designated area and the shellfish therein. The concentrations of fecal bacteria in all the seawater and mussel samples from the designated area during the harvesting season were within the standards of various countries. Pathogenic bacteria were not detected in any of the mussel samples. In our previous study, the hazardous metal levels in all the mussels from the same area were also within the limits of different countries.ConclusionThe mussel products in this area are suitable for consumption based on fecal pollution, pathogenic bacteria, and also heavy metals.

Occurrence of fecal and non-fecal sources bacteria during several overlap rainfall events at Fujiazhuang bathing beach in Dalian, China

With an aim to provide guidance for public health swimming in the beach, as well as provide a scientific basis for beach safety management, a continuous 16-day monitoring after the first rainfall and 6-day monitoring after the last rainfall in the swimming season in 2015 was carried out at Fujiazhuang bathing beach in Dalian to evaluate the effects of rainfall on typical fecal sources (enterococci, human specific bacteroides) and non-fecal bacteria (staphylococcus aureus) contamination. The results showed that the concentration of enterococci using culture dependent method and human bacteroides using real-time PCR always fluctuated with six overlap rainfalls, which had a severe impact on fecal bacteria indicators. During sampling period, the water quality exceeded the single sample standard for enterococci (<35 cfu/100 mL) and human specific bacteroides (<8.6 × 102 copies/100 mL) in 100% and 96% of the samples, respectively, higher concentrations were consistently distributed near the drain outlet, indicating that most of the stormwater flowed to the drainage system discharging into the marine. The fecal sources bacteria, enterococci and human specific bacteroides were significantly correlated with each other, both of them have a strong relationship with rainfall (p<0.01), while non-fecal contaminated bacterial concentration showed no correlation with rainfall (p>0.05). Swimmer density is another major factor affecting the concentration of both fecal and non-fecal sources bacteria in seawater. Considering from the public health, it is recommended to reduce the swimming frequence during continuous rainfall period, as well as to increase periodic surveying of highly frequented beaches, especially during periods of peak bather density.

Environmental isotope \(^18 O\) in coastal karst spring waters as a possible predictor of marine microbial pollution

We tested the validity of the traditional hypothesis of a causal effect between rainfall occurrence, groundwater discharging into the sea, and marine microbial contamination. For groundwater characterization, we used the \(^18 O\) isotope. This stable isotope, together with 2 H, proved to be a useful physical, naturally occurring tracer primarily due to its abundance variations at different stages of water cycle. Test locations include Bakar Bay and selected adjacent Rijeka city beaches (Croatia). To test for statistical associations, we used the Panel Data Pairwise Granger Causality test. At examined locations, we found statistically significant relationships between the amount of rainfall and the abundance of \(^18 O\) isotope in groundwater, as well as relationships between the abundance of \(^18 O\) isotope in groundwater and faecal bacteria concentrations. Accordingly, \(^18 O\) isotope, when used as an indicator for the functioning of karstic groundwater systems, may also be used as the predictor of faecal contamination of bathing waters in associated karst littoral areas. We believe this physical method could be a valuable addition to present methods of predicting microbiological contamination and economic allocation of stock and flow pollutants in scarce common pool resources as fresh water basins, springs and beaches.

Effect of ceftriaxone on the intestinal epithelium and microbiota in neonatal mice

To investigate the effect of ceftriaxone on the intestinal epithelium and microbiota in mice in the early-life stage, as well as the recovery of the intestinal epithelium and reconstruction of intestinal microbiota in adult mice. A total of 36 BALB/C neonatal mice were randomly divided into control group and experimental group, with 18 mice in each group. The mice in the experimental group were given ceftriaxone 100 mg/kg every day by gavage within 21 days after birth. Those in the control group were given an equal volume of normal saline by gavage. Immunohistochemistry was used to measure the expression of Ki67, Muc2, and ZO-1 in the intestinal epithelium. qPCR and next-generation sequencing were used to analyze the overall concentration and composition of fecal bacteria. After 21 days of ceftriaxone intervention, the experimental group had a significant reduction in body weight, a significant reduction in the expression of Ki67 and ZO-1 and a significant increase in the expression of Muc2 in intestinal epithelial cells, a significant reduction in the overall concentration of fecal bacteria, and a significant increase in the diversity of fecal bacteria compared with the control group (P&lt;0.05). Firmicutes was the most common type of fecal bacteria in the experimental group, and there were large amounts of Staphylococcus and Enterococcus. The experimental group had a certain degree of recovery of the intestinal epithelium, but there were still significant differences in body weight and the structure of intestinal microbiota between the two groups at 56 days after birth (P&lt;0.05). Early ceftriaxone intervention significantly affects the development of the intestinal epithelium and the construction of intestinal microbiota in the early-life stage. The injury of the intestinal microbiota in the early-life stage may continue to the adult stage and affect growth and development and physiological metabolism.