Human enteric viruses, such as enteric adenoviruses (HAdV), are known to be involved with gastrointestinal disorders, especially acute gastroenteritis. Several studies have used HAdV as an indicator of water quality, since they are considered highly stable and widely distributed viruses in water matrices. The aim of this study was to detect and genotype HAdVs in water matrices impacted by discharges of treated effluents from wastewater treatment plants (WWTPs). Wastewater treatment plants from the sanitary system of the Brazilian Federal District were assessed in 2018 and 2019. Samples were collected upstream and downstream from discharge points for each WWTP. Viral concentration based on adsorption-elution and conventional PCR was used for molecular detection, and positive samples were sequenced for phylogenetic analysis. Pluviosity data for the period in which the samples were collected were obtained. Our results demonstrated the presence of HAdVs in 27.2% (61/224) of the samples. The positivity was significantly higher in downstream samples compared to upstream. Moreover, the HAdV positivity was higher in downstream samples collected from receiving water bodies impacted by secondary-level WWTPs in comparison with those impacted by tertiary-level WWTPs. Phylogenetic analysis demonstrated the presence of genotypes 40 and 41, with prevalence of HAdV genotype 41. Despite the predominance of HAdV-41, an increasing frequency of the HAdV-40 was associated with higher pluviosity. In conclusion, this study is the first documentation in the Brazilian Federal District dealing with the prevalence and diversity of HAdVs in several WWTP, along with their correlation with rainfall index.
Background
Aquatic matrices impacted by sewage may shelter carbapenem-resistant (CR) Gram-negative bacilli (GNB) harboring resistance genes of public health concern. In this study, sewage treatment plants (STPs) servicing well-defined catchment areas were surveyed for the presence of CR-GNB bearing carbapenemase genes (blaKPC or blaNDM).
Results
A total of 325 CR-GNB were recovered from raw (RS) and treated (TS) sewage samples as well as from water body spots upstream (UW) and downstream (DW) from STPs. Klebsiella-Enterobacter (KE) group amounted to 116 isolates (35.7%). CR-KE isolates were recovered from TS, DW (35.7%) and RS samples (44.2%) (p = 0.001); but not from UW samples. KE isolates represented 65.8% of all blaKPC or blaNDM positive strains. The frequency of blaKPC-or-NDM strains was positively associated with the occurrence of district hospitals located near STPs, as well as with the number of hospitalizations and of sewer connections serviced by the STPs. blaKPC-or-NDM strains were recovered from ST samples in 7 out of 14 STPs, including four tertiary-level STPs; and from 6 out of 13 DW spots whose RS samples also had blaKPC-or-NDM strains.
Conclusions
Clinically relevant GNB bearing blaKPC-or-NDM resist sewage treatments and spread into environmental aquatic matrices mainly from STPs impacted by hospital activities.
Noroviruses (NVs) are responsible for most cases of human nonbacterial
gastroenteritis worldwide. Some parameters for the purification of NV virus-like
particles (VLPs) such as ease of production and yield were studied for future
development of vaccines and diagnostic tools. In this study, VLPs were produced by
the expression of the VP1 and VP2 gene cassette of the Brazilian NV isolate, and two
purification methods were compared: cesium chloride (CsCl) gradient centrifugation
and ion-exchange chromatography (IEC). IEC produced more and purer VLPs of NV
compared to CsCl gradient centrifugation.
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