Detection of SARS-CoV-2 RNA in hospital wastewater from a low COVID-19 disease prevalence area

Previous studies on SARS-CoV and MERS-CoV reported the detection of viral RNA in the stool of both symptomatic and asymptomatic individuals. These clinical observations suggest that municipal and hospital wastewater from affected communities may contain SARS-CoV-2 RNA. Recent studies have also reported the presence of SARS-CoV-2 RNA in human feces. Wastewater-based epidemiology (WBE) is a promising approach to understand the prevalence of viruses in a given catchment population, as wastewater contains viruses from symptomatic and asymptomatic individuals. The current study reports the first detection of SARS-CoV-2 RNA in untreated wastewater in Slovenia. Two sizes of centrifugal filters were tested: 30 kDa and 10 kDA AMICON® Ultra-15 Centrifugal Filters, where 10 kDA resulted in a higher concentration factor and higher recovery efficiency. The results in hospital wastewater show that WBE can be used for monitoring COVID -19 and could be applied in municipal wastewater treatment plants as a potential complementary tool for public health monitoring at population level.

Antimicrobial Resistance and Molecular Characterization of Extended-Spectrum β-Lactamases and Other Escherichia coli Isolated from Food of Animal Origin and Human Intestinal Isolates

Antibiotics have always appeared miraculous, saving innumerable lives. However, the unwise use of antimicrobial drugs has led to the appearance of resistant bacteria. The purpose of this study was to evaluate antimicrobial resistance in Escherichia coli (n =160) isolated from food of animal origin. The focus was on E. coli -producing extended-spectrum β-lactamases. E. coli was chosen because it is a part of the normal microbiota in mammals and can enter the food chain during slaughtering and food manipulation. Subsequently, its resistance genes can be transferred to pathogenic bacteria and human microbiota. Phenotypic and genotypic analyses of selected antimicrobial resistances were carried out together with a molecular analysis of virulence genes. E. coli isolates from food of animal origin were compared with clinical E. coli strains isolated from the human intestinal tract. Extended-spectrum β-lactamase-producing E. coli isolates were found in 9.4% of food isolates and in 1.8% of intestinal isolates. Phylogenetically, the majority of food (86.3%) and intestinal E. coli (58.1%) isolates were found to belong to the commensal phylogenetic groups A and B1. The distribution of 4 of 14 analyzed virulence factors was similar in the food and intestinal isolates. Strains isolated from food in Slovenia harbored resistance genes and virulence factors, which can constitute a problem for food safety if not handled properly.

High genetic similarity of ciprofloxacin-resistant Campylobacter jejuni in central Europe

Campylobacteriosis is the leading zoonosis in the European Union with the majority of cases attributed to Campylobacter jejuni. Although the disease is usually self-limiting, some severe cases need to be treated with antibiotics, primarily macrolides and quinolones. However, the resistance to the latter is reaching alarming levels in most of the EU countries. To shed light on the expansion of antibiotic resistance in central Europe, we have investigated genetic similarity across 178 ciprofloxacin-resistant C. jejuni mostly isolated in Slovenia, Austria and Germany. We performed comparative genetic similarity analyses using allelic types of seven multilocus sequence typing housekeeping genes, and single nucleotide polymorphisms of a quinolone resistance determining region located within the DNA gyrase subunit A gene. This analysis revealed high genetic similarity of isolates from clonal complex ST-21 that carry gyrA allelic type 1 in all three of these central-European countries, suggesting these ciprofloxacin resistant isolates arose from a recent common ancestor and are spread clonally.

An improved 16S rRNA based PCR method for the specific detection of Salmonella enterica

A molecular method for the detection of Salmonella enterica strains based on 16S rRNA sequence analysis was developed by a modification of the previously described PCR primer 16SFI [J. Appl. Bacteriol. 80 (1996) 659], which was combined with a newly developed primer annealing at the position 66-82. Only approximately two thirds of now determined Salmonella 16S rRNA sequences contained a region identical to the 16SFI primer sequence and the reverse primer 16SIII was also not specific. Combined, these two primers have been claimed to allow the specific detection of all Salmonella; however, in this study, they did not recognize S. bongori and 3 out of 78 tested S. enterica strains. They also identified some of the tested Enterobacter cloacae strains as Salmonella. On the contrary, the new primer pair, MINf and MINr, made it possible to recognize correctly all of the 78 tested S. enterica strains, representing 31 different Salmonella serovars. None of the 23 non-Salmonella strains from the related gamma-proteobacterial genera was incorrectly recognized as belonging to S. enterica.

Preliminary characterization of a tentatively novel rumen bacterial species from the genus Treponema

A new spirochetal strain was isolated from the rumen of a black-and-white Holstein cow and preliminarily characterized. The sugar fermentation tests and morphological observations indicated this organism to be a member of a novel, as yet undescribed spirochetal rumen species. The small subunit ribosomal RNA genes were amplified and the PCR products were cut with the restriction endonucleases TaqI, DdeI, HhaI and Sau3AI. The comparison of the observed RFLP with the hypothetical fragment lengths of the computer analyzed 16S rRNA sequences from the type strains of the ruminal spirochetes Treponema bryantii and T. saccharophilum confirmed the tentative novel identification. Transmission electron microscopy showed that the bacterium has the typical spirochetal structures, i.e. the outer sheath, the protoplasmic cylinder and the axial filament (it is not yet clear how many flagella compose the filament). An additional extracellular structure was observed which appeared as an exocytoplasmic polar flagellum, approximately 2 microns long and protruding from one tip of the cell. The average size of the cells was 0.5 x 10-15 microns and the wavelengths and the amplitudes of the primary coils were 2.9 and 1.3 microns, respectively.