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Antimicrobial resistance (AMR) is recognized as a global threat. AMR bacteria accumulate in sewage sludge however, knowledge on the persistence of human pathogens and AMR in the sludge line of the wastewater treatment is limited. Sludge can be used, with or without additional treatment, as fertilizer in agricultural fields. The aim of this study is to obtain knowledge about presence of human pathogens and AMR in the sewage sludge, before and after the anaerobic digestion (AD) applying innovative combinations of methods. Fifty sludge samples were collected. Cultivation methods combined with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and Antibiotic Susceptibility Test (AST) were used obtaining knowledge about the microbial community, pathogens, and antibiotic resistant bacteria while the droplet digital Polymerase Chain Reaction (ddPCR) was performed to detect most common AMR genes. In total, 231 different bacterial species were identified in the samples. The most abundant species were spore-forming facultative anaerobic bacteria belonging to Bacillus and Clostridium genera. The AD causes a shift in the microbial composition of the sludge (p = 0.04). Seven pathogenic bacterial species constituting 188 colonies were isolated and tested for susceptibility to Clindamycin, Meropenem, Norfloxacin, Penicillin G, and Tigecycline. Of the Clostridium perfringens and Bacillus cereus isolates 67 and 50 %, respectively, were resistant to Clindamycin. Two B. cereus and two C. perfringens isolates were also resistant to other antibiotics showing multidrug resistance. ARGs (blaOXA, blaTEM, ermB, qnrB, tet(A)-(W), sulI-II) were present at 7–8 Log gene copies/kg of sludge. AD is the main driver of a reduction of some ARGs (1 Log) but resistant bacteria were still present. The results showed the usefulness of the integration of the proposed analytical methods and suggest a decrease in the risk of presence of cultivable pathogens including resistant isolates after AD but a persistent risk of ARGs’ horizontal transmission.

Background: Urban air pollution is recognized as a critical problem for public health and is classified as a carcinogen for humans. A great number of studies have focused on the monitoring of urban air mutagenicity. One of the best-known and applied methods for assessing mutagenicity is the Ames test, a bacterial reverse mutation test. The classic protocol for assessing air mutagenicity involves the concentration of particulate matter (PM) on filters and subsequent extraction using organic solvents. This work aimed to develop a method for the evaluation of air mutagenicity directly impacted by air on microbial plates already containing an Ames’ microbial sensor. Methods: A specific six-month sampling campaign was carried out in Turin in a period with high air pollution. Samples were tested for mutagenicity on Salmonella typhimurium strains TA98, TA100, and YG1024 with the traditional method and with the new direct method. Results: The new protocol is able to evaluate the mutagenicity of the sampled air and obtain repeatable results. The final sensitivity is similar to the traditional method (≈10 net revertants/m3); however, the mutagenic response is due to the complete air pollution mixture, including volatile and semivolatile pollutants avoiding the concentration of filters and the following laborious extraction procedures. Conclusions. Despite some critical issues in contamination control, the method is easier, faster, and less expensive than traditional methods.

IntroductionType 1 diabetes (T1D) risk involves genetic susceptibility but also epigenetics, environment, and behaviors. Appropriate metabolic control, especially quickly after the diagnosis, is crucial for the patient quality of life.MethodsThis study aimed to produce a quantitative comparison of the behavior, nutrition habits, and gut microbiota composition between the onset and the 1-year follow-up in 35 children with T1D.Results and discussionAt follow-up, with the metabolic control, many parameters improved significantly, with respect to the onset, such as glycated hemoglobin (−19%), body mass index (BMI), and also nutritional behaviors, such as normal calorie intake (+6%), carbohydrate intake (−12%), extra portion request (−4%), and meals distribution during the day. Moreover, glycated hemoglobin decrement correlated with both total and rapid absorption carbohydrate intake (Spearman's rho = 0.288, 95% CI 0.066–0.510, p = 0.013), showing as the nutritional behavior supported the insulin therapy efficiency. The next-generation sequencing (NGS) analysis of microbiota revealed abundance differences for Ruminococcus bromii and Prevotella copri (higher at onset, p < 0.001) and the genera Succinivibrio and Faecalibacterium (lower at onset, p < 0.001), as a consequence of nutritional behavior, but it was not the only changing driver. The qRT-PCR analysis showed significant variations, in particular for Bacteroidetes and Bifidobacterium spp. (+1.56 log gene copies/g stool at follow-up, p < 0.001). During the year, in 11% of the patients, severe clinical episodes occurred (hypoglycemic or ketoacidosis). The likelihood of a severe hypoglycemic episode was modulated when the Methanobrevibacter smithii amount increased (odds ratio 3.7, 95% CI 1.2–11.4, p = 0.026). Integrated evaluation, including nutritional behavior and microbiota composition, could be considered predictive of the metabolic control management for children cohort with a recent diagnosis of T1D.

Rapid population growth and urbanization have led to increased waste generation rates. Avoiding, reducing and reusing waste is imperative in the international approach to avoid impacting disposals. Composting plants are crucial for better organic waste management, although one of their environmental impacts is bioaerosol production, which can lead to adverse health effects. This work analyzed bioaerosol contamination in composting plants through multiple analytic methods, including culture-based techniques and qPCR, subfractionated PM10, and PM4.5 sampling. The aim was to identify indicators useful for assessing the human health risk associated with bioaerosol exposure during organic waste treatment. Two composting plants and four different areas (reception/selection, methanization, composting and refinement) were selected for sampling. The analysis revealed high contamination levels and large microbial heterogeneity both for PM (until to 3 times above the guideline value) and bioaerosol samples (until to 3 magnitude orders above the proposed reference value). Bacillus spp., Saccharopolyspora, and Thermomyces always showed detectable but highly variable concentrations (ranging from 2.12 to 4.86, from 3.65 to 7.30 and from 3.45 to 6.94 Log gene copies/m3 respectively). They correlated positively and significantly with other measured microbial parameters, suggesting their potential use as indicators of biological contamination in composting plants. Moreover, the integration of culture indipendent methods can increase the monitoring sensitivity and improve the bioaerosol risk assessment. The reduction of bioaerosol exposure levels in composting plants remains a primary goal but it requires in-depth characterization of the complex bioaerosol composition, its airborne dispersion, and its association with specific adverse health outcomes.

Urban air pollutants are a major public health concern and include biological matters which composes about 25% of the atmospheric aerosol particles. Airborne microorganisms were traditionally characterized by culture-based methods recognizing just 1.5–15.3% of the total bacterial diversity that was evaluable by genome signature in the air environment (aerobiome). Despite the large number of exposed people, urban aerobiomes are still weakly described even if recently advanced literature has been published. This paper aims to systematically review the state of knowledge on the urban aerobiome and human health effects. A total of 24 papers that used next generation sequencing (NGS) techniques for characterization and comprised a seasonal analysis have been included. A core of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroides and various factors that influenced the community structure were detected. Heterogenic methods and results were reported, for both sampling and aerobiome diversity analysis, highlighting the necessity of in-depth and homogenized assessment thus reducing the risk of bias. The aerobiome can include threats for human health, such as pathogens and resistome spreading; however, its diversity seems to be protective for human health and reduced by high levels of air pollution. Evidence of the urban aerobiome effects on human health need to be filled up quickly for urban public health purposes.

Environmentally sustainable methods of waste disposal are a strategic priority. For organic waste management and innovative biological treatments present advantageous opportunities, although organic waste treatment also includes environmental drawbacks, such as bioaerosol production. This study aims to evaluate bioaerosol spread during an innovative experimental treatment. The process consists of two anaerobic steps: acidogenesis, which includes polyhydroxyalkanoate accumulation, followed by methanogenesis. Bioaerosol, PM10, and endotoxin concentrations were measured at three sampling points during different campaigns to evaluate: (1) the background levels, (2) the contamination produced in the pre-treatment stage, and (3) the residual contamination of the outgoing digested sludge. Environmental PM10 seemed to be generally quite contained, while the endotoxin determination was close to 90 EU/m3. Significant microbial concentrations were detected during the loading of the organic fraction of municipal solid waste (fungi > 1300 CFU/m3, Bacillus genus (≈103 CFU/m3), higher Clostridium spp. and opportunistic human pathogens such as Pseudomonas aeruginosa and Klebsiella pneumoniae), suggesting a significant contamination level. Such results are useful for hazard identification in the risk assessment of innovative processes, as they reveal contaminants potentially harmful to both workers’ health and the environment.

Bioaerosol characterization represents a major challenge for the risk assessment and management of exposed people. One of the most important bioaerosol sources is the organic waste collection and treatment. This work analyzed and discussed the literature with the purpose of investigating the main techniques used nowadays for bioaerosol monitoring during organic waste treatment. The discussion includes an overview on the most efficient sampling, DNA extraction, and analysis methods, including both the cultural and the bio-molecular approach. Generally, an exhaustive biological risk assessment is not applied due to the organic waste heterogeneity, treatment complexity, and unknown aerosolized emission rate. However, the application of bio-molecular methods allows a better bioaerosol characterization, and it is desirable to be associated with standardized cultural methods. Risk assessment for organic waste workers generally includes the evaluation of the potential exposition to pathogens and opportunistic pathogens or to other microorganisms as biomarkers. In most cases, Saccharopolyspora rectivirgula, Legionella spp., Aspergillus spp., and Mycobacterium spp. are included. Future perspectives are focused on identifying common composting biomarkers, on investigating the causality process between chronic bioaerosol exposure and disease onset, and finally, on defining common exposure limits.