Search Results (61)

Background/Objectives: Water pollution caused by human activities disrupts ecosystems and promotes the spread of antimicrobial resistance genes (ARGs), posing a public health threat. This study investigated the presence of resistant Gram-negative bacteria and resistance genes in water from two sites occasionally exposed to domestic and hospital effluents, the Carioca River (CR) and Rodrigo de Freitas Lagoon (RFL), both used for recreation. Methods: Physicochemical parameters and coliform levels were measured. Bacterial isolates were identified by Matrix-Assisted Laser Desorption Ionization–Time-of-Flight Mass Spectrometry (MALDI-TOF MS) and tested for antimicrobial susceptibility using disk diffusion. The Minimum Inhibitory Concentration (MIC) was determined using the E-test^® and broth microdilution methods. PCR was used to detect carbapenem resistance and other ARGs from the DNA of bacterial isolates obtained from water samples. Results: CR presented signs of environmental degradation, with low dissolved oxygen and high coliform counts. One Citrobacter braakii isolate showed resistance to all tested antimicrobials, raising concern for untreatable infections. Carbapenem-resistant isolates accounted for 49.4% of the total, harboring bla_KPC (20%), bla_TEM (5%), bla_VIM (5%), and bla_SPM (5%). The intl1 gene was found in 10% of isolates, indicating potential horizontal gene transfer. Conclusions: The findings from a one-day sampling reveal the presence of multidrug-resistant bacteria that carry antimicrobial resistance genes in polluted aquatic systems. These highlight the connection between water contamination and antimicrobial resistance. The evidence underscores the urgent need for environmental monitoring and effective management strategies to reduce public health risks. Full article

Quality control of drinking water is essential for safeguarding public health, particularly in densely populated urban environments. Environmental microbiological monitoring can complement conventional surveillance by providing deeper insights into the dissemination of pathogens and antimicrobial resistance genes within aquatic systems. In this study, we assessed the quality of wastewater and treated water from two urban water supply systems, representing the southern and northern regions of Porto Alegre, Rio Grande do Sul, Brazil, across four climatic seasons between 2024 and 2025. Fifteen water samples were analyzed, including raw water from Guaíba Lake and treated water collected from public distribution points. The Water Quality Index was calculated, microbiological indicators were quantified, and carbapenem resistance genes were detected using molecular assays. Most treated water samples complied with established bacteriological standards; however, the bla_OXA-48-like gene was recurrently detected in both wastewater and treated water. No resistance genes were identified during the summer, whereas the bla_VIM gene was detected exclusively in spring samples. The presence of carbapenem resistance genes in the absence of cultivable coliforms suggests the persistence of extracellular DNA or viable but non-culturable bacteria, highlighting limitations inherent to conventional microbiological monitoring. Integrating classical microbiological methods with molecular assays enables a more comprehensive assessment of water quality and strengthens evidence-based decision-making within a One Health framework. Full article

Composting represents a sustainable and effective strategy for converting organic waste into nutrient-rich soil amendments, providing a safer alternative to raw manure, which poses significant risks of soil, crop, and water contamination through pathogenic microorganisms. This study, conducted under semi-arid Moroccan conditions, investigated the efficiency of co-composting green garden waste with sheep manure in an open window system, with the objective of assessing pathogen inactivation and evaluating compost quality. The process, conducted over 120 days, maintained thermophilic temperatures exceeding 55 °C, effectively reducing key pathogens including Escherichia coli, total coliforms, Staphylococcus aureus, and sulfite-reducing Clostridia (SRC), while Salmonella was not detected throughout the composting period. Pathogen reductions exceeded 3.52-log despite moderate temperature fluctuations, indicating that additional sanitization mechanisms beyond heat contributed to inactivation. Compost quality, assessed using the CQI, classified Heap 2 (fallen leaves + sheep manure) as good quality (4.06) and Heap 1 (green waste + sheep manure) as moderate quality (2.47), corresponding to differences in microbial dynamics and compost stability. These findings demonstrate that open windrow co-composting is a practical, low-cost, and effective method for safe organic waste management. It supports sustainable agriculture by improving soil health, minimizing environmental and public health risks, and providing guidance for optimizing composting protocols to meet regulatory safety standards. Full article

The accelerating pace of global population growth, urbanization, and industrialization is exerting considerable pressure on freshwater resources. In developing countries, where infrastructure constraints often hinder the adoption of advanced treatment technologies, cost-effective and efficient wastewater solutions are essential. Algal–bacterial bioremediation represents a promising, eco-friendly method for removing organic pollutants through biological processes. This study evaluates a hybrid treatment system composed of three ponds: a covered anaerobic pond for organic matter digestion, a microalgal pond equipped with rotating biological contactors (RBCs) that facilitate interactions between heterotrophic bacteria and diatoms, and a final settling pond. Granular activated carbon embedded within the RBC enhances biofilm formation by attracting heterotrophic bacteria, thereby increasing treatment efficiency. Under optimal conditions—10 g of activated carbon and 1.7 d hydraulic retention time—the system achieved removal efficiencies of 95.8% for total suspended solids (TSS), 96.3% for turbidity, 85% for biological oxygen demand (BOD), and 99.9% for Escherichia coli. Bacteriological analysis showed complete removal of fecal coliform and total coliform. The characteristics of the outflow treated wastewater are 3 mg/L, 0.9 NTU, and 3.2 mg/L for TSS, turbidity, and BOD, respectively, while E. coli detection is under detection limit. The treated effluent complies with Category A for the reuse of treated wastewater in the Egyptian code for the reuse of treated municipal wastewater for agricultural purposes, offering a scalable and sustainable solution for wastewater management in resource-constrained regions. Full article

Traditional pork meat products produced through artisanal smoking and drying techniques are highly appreciated for their distinctive sensory characteristics; however, such practices may raise concerns regarding both chemical and microbiological safety. The present study aimed to assess the occurrence of selected polycyclic aromatic hydrocarbons (PAHs) and hygiene- and safety-related microorganisms in traditionally processed pork meat products collected from local markets and small-scale producers. A total of 140 samples were analyzed for four marker PAHs—benzo[a]pyrene (BaP), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), and chrysene (Chr)—using gas chromatography–mass spectrometry (GC–MS). Microbiological contamination was evaluated through standard plate count techniques, and the presence of Listeria monocytogenes and Salmonella serovars was determined using selective isolation methods, followed by PCR confirmation of pathogenic strains. PAH concentrations varied widely: BaP (0.3–1.8 µg/kg), BaA (0.5–2.4 µg/kg), BbF (0.8–3.1 µg/kg) and Chr (0.4–2.0 µg/kg), with ΣPAH₄ (Sum of PAH4, referring to the total concentration of the four-priority polycyclic aromatic hydrocarbons) ranging from 2.5 to 8.3 µg/kg. Smoked sausages showed the highest contamination (BaP: 1.8 µg/kg; ΣPAH₄: 8.3 µg/kg), significantly exceeding levels in dry-cured ham (BaP: 1.2 µg/kg; ΣPAH₄: 6.1 µg/kg) and smoked bacon (BaP: 0.9 µg/kg; ΣPAH₄: 5.4 µg/kg) (Kruskal–Wallis, p < 0.0001). Although all samples complied with the EU ΣPAH₄ limit (12 µg/kg), 15% exceeded the BaP limit of 2.0 µg/kg, primarily among artisanal sausages. Microbiological analyses revealed total coliform counts between 1.5 × 10² and 6.2 × 10⁴ CFU/g, while Enterobacteriaceae ranged from 2.0 × 10² to 4.9 × 10⁴ CFU/g. Samples obtained from unregulated producers exhibited higher bacterial loads, indicating suboptimal hygiene during processing and storage. A moderate positive correlation was identified between total coliform and Enterobacteriaceae counts (r = 0.59, p < 0.05). Moreover, Salmonella serovars was detected in ten sausage samples, and Listeria monocytogenes was confirmed in three samples of traditional products. Overall, the findings suggest that although PAH contamination generally complied with EU safety limits, occasional exceedances of benzo[a]pyrene and elevated microbial indicators underscore the need for stricter control of smoking parameters, fuel sources, and hygienic handling. Implementation of standardized smoking protocols and good manufacturing practices (GMP) is recommended to enhance the safety and quality of traditional pork meat products Full article

Wastewater-based epidemiology (WBE) is an effective tool for assessing health risks in rural areas with limited access to health care. Wastewater treatment plants (WWTPs) allow for the monitoring of pathogenic microorganisms, which is key to detecting viral integrity and bacterial viability to assess health risks. This study evaluated five rural WWTPs in Chile during 2022 in two seasons (autumn–winter and spring–summer). SARS-CoV-2, norovirus GI/GII, and HAdV-F40/41 was analyzed, along with antibiotic-resistant coliforms. Influent and effluent samples were used, with viral integrity analysis by propidium monoazide and culture methods to assess bacterial resistance. Despite the low number of clinical cases, SARS-CoV-2 was detected in all influent samples. Intact viral particles of NoV GI (78%), NoV GII (72%), and HAdV-F40/41 (65%) were found. This suggests that they may still be infectious. Viral removal ranged from 74% to 100%, although intact HAdV was detected in effluent (6.2%). Coliforms resistant to various antibiotics were detected and partially removed (22–100%). Removal efficiency depends on the type of treatment and the season of the year. WWTPs act as temporary reservoirs of infectious agents. This study reinforces the usefulness of WBE in rural contexts and WWTPs as barriers or not to these contaminants to the environment. Full article

Background: Dental unit water lines (DUWLs) can harbor microbial contamination, posing risks for cross-infection to patients and dental staff. This study assessed the prevalence of bacterial contamination in DUWLs at primary healthcare centers in Kuwait during 2022–2023 and examined variation by year, governorate, and sampling outlet. Methods: A retrospective cross-sectional analysis was conducted using 3290 water test results from six governorates. Data were obtained from the Environmental Health Department, Ministry of Health, and analyzed using STATA 17. Contamination was defined as a total plate count (TPC) > 100 CFU/mL or presence of coliforms, Escherichia coli, Pseudomonas aeruginosa, or fecal streptococci. Descriptive and logistic regression analyses were performed. Results: Overall contamination prevalence was 16.8%. Rates were higher in 2023 (19.8%) than in 2022 (13.7%) and higher in Mubarak Alkabeer governorate (23%) and cup filler outlets (18.9%). Logistic regression showed significantly increased odds of contamination in 2023 (OR = 1.6; 95% CI: 1.3–2.0), Mubarak Alkabeer (OR = 1.4; 95% CI: 1.1–1.9), and cup fillers (OR = 1.3; 95% CI: 1.1–1.6). P. aeruginosa was detected in 1.3% of samples. Conclusions: One in six DUWL samples exceeded Kuwait’s strict microbial safety threshold. Findings highlight spatial and procedural variations in contamination and underscore the need for enhanced disinfection protocols, preventive maintenance, and targeted staff training to ensure waterline safety. Full article

This study provides a comprehensive characterization of the microbiological, chemical, and sensory profiles of Sicilian Canestrato Fresco (SCF) cheese, a traditional agri-food product (TAP) made from raw cow’s milk using artisanal methods and typically consumed after 20 d of ripening. Plate count analyses confirmed high levels of mesophilic lactic acid bacteria (LAB) exceeding 10⁸ CFU/g. Both rod- and coccus-shaped LAB populations were present at these elevated levels. Pathogens such as Listeria monocytogenes and Salmonella spp. were not detected, although potential contaminants including Enterobacteriaceae, total coliforms, and Escherichia coli were detected at levels of 1.0–3.5 log CFU/g. High-throughput sequencing confirmed LAB as the dominant taxa, comprising the majority of the bacterial community, which accounted for 78.12% to 99.63% of the total relative abundance (RA) across all cheese samples. The fatty acid profile was typical of cow’s milk cheeses, with long-chain fatty acids (C15–C18) representing ~75% of the total, followed by medium- (~17%) and short-chain (<8%) fatty acids. Volatile organic compound analysis showed free fatty acids as the most abundant class, followed by esters, alcohols, ketones, and aldehydes. These findings highlight the role of traditional practices in preserving the sensory and chemical identity of SCF cheese. However, the presence of hygiene indicators suggests a need for improving sanitary measures along the production chain. Future research should explore the impact of targeted microbial management and packaging conditions to enhance both safety and product standardization without compromising artisanal traits. Full article

Coastal fecal contamination is a global public health concern, particularly due to waterborne protozoan parasites such as Giardia duodenalis and Blastocystis sp. Concepcion Bay (Chile) is an important recreational and productive area in Chile. Nevertheless, it is impacted by two submarine outfalls and a rural sewage treatment plant, which may contribute to fecal pollution. This study evaluated the presence of waterborne parasites in Aulacomya atra mussels intended for human consumption. The mussels were collected from three sectors of the bay: northern, central, and southern. A total of 600 mussels were analyzed as accumulators using PCR targeting SSU-rDNA and β-giardin genes for the detection of Blastocystis sp. and G. duodenalis, respectively. Additionally, thermotolerant coliforms were quantified using the most probable number (MPN) method. Both parasites and coliforms were detected in all sectors, with the southern zone showing the highest number of positive samples, indicating a localized public health concern. This is the first report of these protozoa in mussels from Concepción Bay. The findings highlight the need for regulatory frameworks to control protozoan discharge and reduce pathogen transmission risks in coastal ecosystems, especially in areas with high recreational and economic activity, both in Chile and worldwide. Full article

(1) Background: The Guarapiranga reservoir, located in the metropolitan region of São Paulo (RMSP), plays an important role in supplying water to the population. However, the growing urbanization in the region, which has occurred in a disorderly manner and lacks basic sanitation infrastructure, has had a detrimental impact on the reservoir’s conditions. The aim of this study was to evaluate the physicochemical parameters and detect coliforms to determine the water quality of the Guarapiranga reservoir, as well as to characterize the microbial diversity and antimicrobial-resistance genes (ARGs) present in the reservoir water. (2) Methods: Four sampling campaigns of the Guarapiranga reservoir were carried out between October 2020 and July 2022. Physicochemical analyses, and selective microbiological culture for coliforms, as well as the extraction of bacterial DNA for subsequent sequencing and search for ARGs were carried out. (3) Results: Analysis of the physicochemical results showed a progressive reduction in the quality of the reservoir’s water, and the microbiological tests consistently showed the presence of Escherichia coli, Salmonella spp., Shigella spp. and Klebisiella spp. in the water samples collected from the reservoir. Analyses of the sequencing data showed the predominant presence of the phyla Proteobacteria, Cyanobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, and 12 ARGs were detected in the reservoir. (4) Conclusions: The increase in sewage discharge, mainly due to the growth of irregular housing, has affected the quality of the water, as indicated by the physicochemical analysis and detection of coliforms and ARGs. Full article

The preservation of fermented stinky sea bass (FSSB) has always been a major challenge. In this study, four preservation methods, including partial freezing (PF), freezing (F), irradiation + partial freezing (IPF), and irradiation + freezing (IF), were employed, and their effects on the storage quality of vacuum-packed fermented stinky sea bass were investigated. The results revealed that histamines and coliforms were not detected in any of the four preservation methods. Meanwhile, the TVB-N, peroxide value, pH, and cooking loss showed an increasing trend, while the hardness, springiness, and chewiness showed a decreasing trend, following FSSB vacuum packaging during the 30-day preservation period. Compared with PF or F only, irradiation significantly reduced the total plate number, TVB-N, pH, L*, and whiteness of the FSSB samples but increased the peroxide value content while maintaining the cohesiveness, gumminess, and chewiness. Furthermore, the of 1-butanol, propanal, and (E)-2-pentenal contents increased. In contrast, IPF preservation showed a better ability to maintain the texture quality of the FSSB. The safety index of the FSSB samples complied with the Chinese Standard GB10136-2015 National Food Safety Standards Animal Aquatic Products, following the 30-day preservation period under the four preservation methods. Overall, the experimental results suggest that the IPF preservation method is the most preferable approach to preserving FSSB, which can significantly maintain the product quality and save energy. Full article

This study investigated the microbiological and parasitic quality of sewage sludge treated in drying beds in Algeria, aiming to contribute to a better understanding of the factors influencing sludge safety for potential agricultural applications in the Algerian context. The research focused on various sludge types (liquid, semi-solid, and solid) and their behavior across different seasons. Standard microbiological methods were employed to quantify total coliforms, fecal streptococci, E. coli, and Clostridium. Controls were implemented to ensure accuracy, with positive controls validating detection methods using known quantities of microorganisms and parasites, while negative controls confirmed the absence of contamination in the testing environment. Parasitic contamination was assessed through microscopic examination for protozoa and helminths. Results revealed substantial variation in microbial concentrations across sludge types and seasons. Liquid sludge, particularly during summer, exhibited the highest levels of total coliforms (up to 7.021 log10) and E. coli (up to 6.049 log10), while solid sludge showed lower counts. Seasonal trends indicated increased microbial levels during warmer months. Parasitic contamination was prevalent in 81% of samples, with protozoan cysts (e.g., Giardia intestinalis and Endolimax nanus) and helminth eggs detected. Despite reducing microbial loads, drying processes alone were insufficient, leaving significant contamination. Enhanced protocols are needed, such as longer drying periods, chemical disinfectants, or advanced technologies like anaerobic digestion or composting. This highlights the need for locally adapted treatment strategies. Furthermore, this research provides specific recommendations for improving sewage sludge management practices in Algeria, taking into account the unique environmental and agricultural context of the country. Full article

Background/Objectives: Waste milk harbors many bacteria and antibiotic residues. Calves fed with untreated waste milk have a higher incidence of scours and an increased risk of developing antimicrobial-resistant bacteria. This study aimed to evaluate the efficacy of treatment with copper ions on bacteria and antibiotics contained in bovine waste milk. Methods: Waste milk samples were collected from a dairy farm for seven weeks and were subjected to treatment with copper ions. Total bacterial counts, coliforms, Streptococcus, and Staphylococcus were assessed before and after treatment. Additionally, metagenomic analysis was performed to determine microbial diversity. Results: Before treatment, the total bacterial count average was 4.0 × 10⁶ CFU/mL, 1.7 × 10⁴ CFU/mL for coliforms, 2.6 × 10⁶ CFU/mL for Streptococcus, and 5.4 × 10² CFU/mL for Staphylococcus Copper treatment significantly reduced bacterial counts within 15 min. Total bacteria decreased from 4.0 × 10⁶ CFU/mL to 1.1 × 10² CFU/mL after 30 min; meanwhile, other groups were not detected. The most abundant groups were Lactococcus (29.94%), Pseudomonas (28.89%), and Enterobacteriaceae (21.19%). Beta-lactams were detected in five-sevenths samples, and in one sample they were detected before and at 15 min of treatment but not after 30 min. Conclusions: The effect of treatment with copper ions on the different bacterial groups was significantly effective but showed limited effect on the detection of antibiotics. Full article

Canada is a leading producer of wild lowbush blueberries, most of which are mechanically harvested, washed, individually quick frozen (IQF), and bulk packaged. Still, some berries are harvested by more gentle methods and sold as fresh-packed products. These berries do not undergo a wash step, nor are subjected to antimicrobial treatments. The purpose of this study was to conduct a microbiological survey of berries harvested in the province of Nova Scotia to assess their potential for harborage of bacterial foodborne pathogens. A combination of standardized plate count methods and 3M-Petrifilm protocols were used to enumerate total aerobic mesophilic bacteria (APC), yeasts and molds (YMC), coliforms, and generic E. coli, the latter being an indicator of fecal contamination. Overall, APC and YMC levels were 1.2 and 0.5 log greater, respectively, for berries collected early in the harvest season versus those acquired late season and varied significantly (p < 0.05) between farm (location) and harvest practices used. Berries harvested by our team using sanitized hand rakes (SH) had consistently lower APC and YMC levels than those harvested by farm crews. Yet, when gentle harvesting (GH) methods (hand-raking, walk-behind or modified mechanical harvesters) were employed on farms, lower numbers were generally observed compared to berries harvested by traditional tractor-mounted mechanized harvesters (MH). The presence of coliforms (and their levels) was also impacted by the harvest method, with detection rates of ~29%, 73%, and 92% in SH, GH, and MH samples, respectively. Mean counts were < 2.5 log₁₀ CFU/g for both SH and GH berries, but significantly higher (p < 0.05) on MH berries (3.6 log₁₀ CFU/g). Although ~56% of all berry samples collected (n = 350) contained coliforms, only 12 were positive for E. coli, 9 of which were MH samples. Only the latter had numbers > 2 log₁₀ CFU/g, but none tested positive for Shiga toxin-producing serotype O157 (STEC O157) or Salmonella spp. when using internationally recognized selective enrichment and plating methods. ATP luminescence was used to assess the general hygiene of processing lines, whereby “hot spots” for microbial activity were identified, even after cleaning., Standard selective enrichment and plating methods were used for the detection of Listeria monocytogenes on 61 swab samples taken from berry totes or conveyor belts at different times during processing; 4 swabs tested positive for L. monocytogenes. However, the pathogen could not be detected by direct plating on selective agar without prior enrichment; this indicated its numbers were low. The results from this work demonstrated that alternative gentle harvest methods can reduce microbial numbers on wild blueberries. Although the frequency of fecal contamination in berry samples appeared to be low and targeted human pathogens were not detected; this represents a single study conducted over one harvest season. Therefore, it would be prudent for processors to seek effective antimicrobial technologies prior to packaging, while consumers should use caution and thoroughly wash produce before consumption. Where sporadic detection of L. monocytogenes was observed on environmental samples from the processing line, processors must ensure that effective sanitation programs are implemented to avoid potential food safety risks. Full article

The conditions in livestock housing are suitable for the survival of airborne microorganisms, mainly due to high temperatures, humidity, and the presence of organic material. The total count of airborne bacteria concentrations in cattle farms ranged from 3.01 log₁₀ CFU/mL to 6.90 log₁₀ CFU/mL; for coliform bacteria, they were from 2.18 log₁₀ CFU/mL to 3.34 log₁₀ CFU/mL; and for molds, they ranged from 3.00 log₁₀ CFU/mL to 4.57 log₁₀ CFU/mL. Bacteria resistant to antimicrobial substances and resistance genes can be spread on animal farms. Antimicrobial resistance in ubiquitous Escherichia coli isolated from cattle feces was investigated. Minimum inhibitory concentration (MIC) testing was utilized to identify phenotypic resistance profiles, and the PCR method was employed to detect the presence of resistant genes. A higher percentage of resistance was found to amikacin (65%), tetracycline (61%), streptomycin (56%), ampicillin (55%), and nalidixic acid (45%). Multidrug resistance was determined in up to 64.3% of the isolates studied. The most widespread resistance genes were bla_TEM (85.7%), sul2 (66.7%), tetB (52.38%), and sul1 (47.6%). We found that 4.8% of the E. coli isolates had the bla_CMY gene. We found that, despite phenotypic resistance, E. coli isolates do not necessarily carry genes conferring resistance to that particular antimicrobial agent. Full article