Countrywide multi-serotype outbreak of Salmonella Bovismorbificans ST142 and monophasic Salmonella Typhimurium ST34 associated with dried pork sausages in France, September 2020* to January 2021.

The French National Reference Centre for Escherichia coli, Shigella and Salmonella (FNRC-ESS) detected two human clusters of 33 cases (median age: 10 years; 17 females) infected by Salmonella enterica serotype Bovismorbificans, ST142, HC5_243255 (EnteroBase HierCC­cgMLST scheme) in September-November 2020 and of 11 cases (median age: 11 years; seven males) infected by S. enterica serotype 4,12:i:-, ST34, HC5_198125 in October-December 2020. Epidemiological investigations conducted by Santé publique France linked these outbreaks to the consumption of dried pork sausages from the same manufacturer. S. Bovismorbificans and S. 4,12:i:- were isolated by the National Reference Laboratory from different food samples, but both strains were identified in a single food sample only by qPCR. Three recalls and withdrawals of dried pork products were issued by the French general directorate of food of the French ministry for agriculture and food in November 2020, affecting eight supermarket chains. A notification on the European Rapid Alert System for Food and Feed and a European urgent enquiry on the Epidemic Intelligence Information System for Food and Waterborne Diseases and Zoonoses (EPIS-FWD) were launched. No cases were reported outside France. Outbreaks caused by multiple serotypes of Salmonella may go undetected by protocols in standard procedures in microbiology laboratories.

Workers' exposure to bioaerosols from three different types of composting facilities.

Composting is a natural dynamic biological process used to valorise putrescible organic matter. The composting process can involve vigorous movements of waste material piles, which release high concentrations of bioaerosols into the surrounding environment. There is a lack of knowledge concerning the dispersal of airborne microorganisms emitted by composting plants (CP) as well as the potential occupational exposure of composting workers. The aim of this study was to investigate the workers exposure to bioaerosols during working activities in three different types of composting facilities (domestic, manure, carcass) using two different quantification methods (cultivation and qPCR) for bacteria and moulds concentrations. As expected, even if there are differences between all CP frameworks, independently of the type of the raw compost used, the production of bioaerosols increases significantly during handling activities. Important concentrations of mesophilic moulds and mesophilic bacteria were noted in the working areas with a respective maximal concentration of 2.3 × 105 CFU/m3 and 1.6 × 105 CFU/m3. A. fumigatus and thermophilic Actinomycetes were also detected in all working areas for the 3 CP. This study emphases the risks for workers to being in contact with aerosolized pathogens such as Mycobacterium and Legionella and more specifically, L. pneumophila. The presence of high concentration of these bacteria in CP suggests a potential occupational health risk. This study may lead to recommendations for the creation of limits for occupational exposure. There is a need for identifying the standards exposure limits to bioaerosols in CP and efficient recommendation for a better protection of workers' health.

Detection and quantification of airborne norovirus during outbreaks in healthcare facilities.

BACKGROUND: Noroviruses are responsible for at least 50% of all gastroenteritis outbreaks worldwide. Noroviruses GII can infect humans via multiple routes including direct contact with an infected person, fecal matter, or vomitus, and contact with contaminated surfaces. Although norovirus is an intestinal pathogen, aerosols could, if inhaled, settle in the pharynx and later be swallowed. The aims of this study were to investigate the presence of norovirus GII bioaerosols during gastroenteritis outbreaks in healthcare facilities and to study the in vitro effects of aerosolization and air sampling on the noroviruses using murine norovirus as a surrogate. METHODS: A total of 48 air samples were collected during norovirus outbreaks in 8 healthcare facilities. Samples were taken 1 m away from each patient, in front of the patient's room and at the nurses' station. The resistance to aerosolization stress of murine norovirus type 1 (MNV-1) bioaerosols was also tested in vitro using an aerosol chamber. RESULTS: Norovirus genomes were detected in 6 of 8 healthcare centers. The concentrations ranged from 1.35 × 10(1) to 2.35 × 10(3) genomes/m(3) in 47% of air samples. MNV-1 preserved its infectivity and integrity during in vitro aerosol studies. CONCLUSIONS: Norovirus genomes are frequently detected in the air of healthcare facilities during outbreaks, even outside patients' rooms. In addition, in vitro models suggest that this virus may withstand aerosolization.

Candidate proteomic biomarkers for three genogroups of the swine pathogen Streptococcus suis serotype 2.

BACKGROUND: Streptococcus suis, more specifically serotype 2, is a major swine pathogen and an emerging zoonotic agent that causes severe infections such as meningitis, endocarditis, and septicemia. In this study, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI) was used to investigate the protein expression profiles of 45 strains of S. suis serotype 2 that had previously been clustered by multilocus sequence typing (MLST) into three sequence types (ST1, ST25, and ST28) (n = 15 for each ST). RESULTS: The SELDI data were analyzed using the univariate Mann-Whitney and Kruskal-Wallis tests and multivariate statistical methods (heatmap/hierarchical clustering). The heatmap identified 136 cell proteins, and hierarchical clustering provided a 100% correct classification of all fifteen ST1 and ST25 strains and thirteen of the fifteen ST28 strains (87% correct). The univariate statistical analyses of the SELDI protein expression profiles identified nine significant proteins that discriminated the strains of the three STs of S. suis. Of these proteins, two were overexpressed in ST1 (5958 Da and 10249 Da), four in ST25 (5989 Da, 6646 Da, 7421 Da, and 9825 Da), and three in ST28 (4516 Da, 7833 Da, and 9342 Da). Two of the proteins associated with the ST28 strains (p4516 and p9342) were purified and were identified as a putative ABC transporter and a nucleoid-DNA-binding protein, respectively. CONCLUSIONS: SELDI analysis of 45 strains of S. suis allowed to identify nine statistically significant proteins that can be specifically correlated with either ST1, ST25 or ST28. The possible involvement of the overexpressed proteins in the pathology of S. suis infections will require further investigation.

Detection of Streptococcus suis in bioaerosols of swine confinement buildings.

Streptococcus suis is an important swine pathogen that can cause septicemia, meningitis, and pneumonia. Also recognized as an emerging zoonotic agent, it is responsible for outbreaks of human infections in Asian countries. Serotype 2 is the predominant isolate from diseased animals and humans. The aerosolization of S. suis in the air of swine confinement buildings (SCB) was studied. The presence of S. suis in bioaerosols was monitored in SCB where cases of infection had been reported and in healthy SCB without reported infections. Using a quantitative-PCR (qPCR) method, we determined the total number of bacteria (1 × 10(8) to 2 × 10(8) airborne/m(3)), total number of S. suis bacteria (4 × 10(5) to 10 × 10(5) airborne/m(3)), and number of S. suis serotype 2 and 1/2 bacteria (1 × 10(3) to 30 × 10(3) airborne/m(3)) present in the air. S. suis serotypes 2 and 1/2 were detected in the air of all growing/finishing SCB that had documented cases of S. suis infection and in 50% of healthy SCB. The total number of bacteria and total numbers of S. suis and S. suis serotype 2 and 1/2 bacteria were monitored in one positive SCB during a 5-week period, and it was shown that the aerosolized S. suis serotypes 2 and 1/2 remain airborne for a prolonged period. When the effect of aerosolization on S. suis was observed, the percentage of intact S. suis bacteria (showing cell membrane integrity) in the air might have been up to 13%. Finally S. suis was found in nasal swabs from 14 out of 21 healthy finishing-SCB workers, suggesting significant exposure to the pathogen. This report provides a better understanding of the aerosolization, prevalence, and persistence of S. suis in SCB.

Simultaneous Detection of Salmonella spp. and Quantification of Campylobacter spp. in a Real-Time Duplex PCR: Myth or Reality?

In Europe, there is a process hygiene criterion for Salmonella and Campylobacter on broiler carcasses after chilling. The criterion gives indicative contamination values above which corrective actions are required by food business operators. The reference methods for verifying compliance with the criterion for Salmonella and Campylobacter are international standards EN ISO 6579-1 (2017) and EN ISO 10272-2 (2017), respectively. These methods are time-consuming and expensive for food business operators. Therefore, it would be advantageous to simultaneously detect Salmonella spp. and quantify Campylobacter in the same analysis, using the same sample after the pre-enrichment step for Salmonella recovery. A duplex PCR for Salmonella detection and Campylobacter spp. enumeration was developed. Considering the method as a whole, the LOD and LOQ for Campylobacter enumeration were slightly over the limit of 3 log CFU/g set by the process hygiene criterion. A comparison of the duplex PCR method developed with the ISO method on artificially contaminated bacterial suspensions and on naturally contaminated samples demonstrated a good correlation of the results for Campylobacter enumeration when the duplex PCR was performed on samples taken before or after the pre-enrichment step, but revealed a slight bias with a large standard deviation resulting in widely spaced limits of agreement.

Tell me if you prefer bovine or poultry sectors and I'll tell you who you are: Characterization of Salmonella enterica subsp. enterica serovar Mbandaka in France.

Introduction: In north-western France, Salmonella enterica susp. enterica serovar Mbandaka (S. Mbandaka) is most frequently isolated from bovine and dairy samples. While this serovar most often results in asymptomatic carriage, for a number of years it has caused episodes of abortions, which have serious economic consequences for the sector. Interestingly, this serovar is also isolated from Gallus gallus in the same geographic zone. Despite its prevalence in bovines in north-western France, S. Mbandaka has not been broadly studied at the genomic level, and its prevalence and host adaptation are still not fully understood. Methods: In this study, we analyzed the genomic diversity of 304 strains of S. Mbandaka isolated from the bovine and poultry sectors in this area over a period of 5 years. A phylogenetic analysis was carried out and two approaches were followed to identify conserved genes and mutations related to host associations. The first approach targeted the genes compiled in the MEGARESv2, Resfinder, VFDB and SPI databases. Plasmid and phage contents were also investigated. The second approach refers to an in-house algorithm developed for this study that computes sensitivity, specificity, and accuracy of accessory genes and core variants according to predefined genomes groups. Results and discussion: All the analyzed strains belong to the multi-locus sequence type profile ST413, and the phylogenomic analysis revealed main clustering by host (bovine and poultry), emphasizing the circulation of 12 different major clones, of which seven circulate in poultry and five in the bovine sector in France and a likely food production chain adaptation of these clones. All strains present resistance determinants including heavy metals and biocides that could explain the ability of this serovar to survive and persist in the environment, within herds, and in food processing plants. To explore the wild animal contribution to the spread of this serovar in north-western France, we retrieved S. Mbandaka genomes isolated from wild birds from EnteroBase and included them in the phylogenomic analysis together with our collection. Lastly, screening of accessory genes and major variants allowed us to identify conserved specific mutations characteristic of each major cluster. These mutations could be used to design useful probes for food safety surveillance.

Genome sequence of the swine pathogen Streptococcus suis serotype 2 strain S735.

Streptococcus suis is a major swine pathogen responsible for significant, worldwide economic losses in the swine industry, in addition to being an emerging zoonotic agent. Strains of serotype 2 are the most commonly associated with infections causing meningitis, endocarditis, and septicemia. Here we present the genome sequence of S. suis serotype 2 strain S735.

Survival of Campylobacter jejuni Co-Cultured with Salmonella spp. in Aerobic Conditions.

Campylobacter and Salmonella are responsible for the two major foodborne zoonotic diseases in Europe; poultry is the main infection source. Campylobacter cannot grow under aerobic conditions, but can show aerobic survival when co-cultured with other microorganisms; however, its interaction with Salmonella has not been studied yet. In this study, these two bacteria were co-cultured under controlled aerobic conditions. Different concentrations and strains of C. jejuni were incubated with or without different Salmonella serotypes (10 CFU) at 37 °C for 16 h. C. jejuni did not grow after incubation with or without Salmonella. The survival of C. jejuni was observed only for the highest initial concentration of 6 log CFU/mL with or without Salmonella. However, its survival was significantly higher when co-cultured with Salmonella. No survival was observed at lower concentrations. C. jejuni survival was positively affected by the presence of Salmonella but depended on the Salmonella serotype, the C. jejuni strain and the initial concentration. On the other hand, the Salmonella enumerations were not affected by C. jejuni. Our results suggest potential interactions between Salmonella and C. jejuni that require further investigations for a clearer understanding of their behavior in natural habitats.

A national study through a 'Farm-to-fork' Approach to determine Salmonella dissemination along with the Lebanese poultry production chain.

This cross-sectional study was conducted to determine the prevalence of Salmonella at different stages of the broiler production chain and layer flocks in addition to their antibiotic resistance profile and molecular patterns. Over a period of 3 years, different sample matrices were collected from Lebanese farms, slaughterhouses and retail markets. Out of 672 Salmonella serotyped, 514 were analysed for antimicrobial resistance and 214 for clonality using Pulsed-field gel electrophoresis (PFGE). The results highlighted an important prevalence of Salmonella, 30% in farms, 35.8% in slaughterhouses and 22.4% at retail level. A large diversity of serotypes was identified with predominance among Salmonella Infantis (32.9%), Salmonella Enteritidis (28.4%) and Salmonella Kentucky (21.4%). High resistance to nalidixic acid was revealed in all the isolates. The most prominent resistance was exhibited in S. Kentucky and S. Infantis. The latter was resistant to tetracycline (99%), streptomycin (88.2%) and remarkable multi-drug resistance (MDR) (89.7%). All S. Kentucky isolates were resistant to ciprofloxacin, MDR (62.4%) and 6% were resistant to extended-spectrum cephalosporin (ESCs). One persistent clone of S. Enteritidis was found common between poultry and humans. Similar genomic profiles were detected between farms, slaughterhouses and retail suggesting the dissemination of identical clones throughout the food chain possibly due to weak barriers preventing such transmission.

Amoeba host model for evaluation of Streptococcus suis virulence.

The Gram-positive bacterium Streptococcus suis is a major swine pathogen worldwide that causes meningitis, septicemia, and endocarditis. In this study, we demonstrate that the amoeba Dictyostelium discoideum can be a relevant alternative system to study the virulence of S. suis.

The SspA subtilisin-like protease of Streptococcus suis triggers a pro-inflammatory response in macrophages through a non-proteolytic mechanism.

BACKGROUND: Streptococcus suis is a major swine pathogen worldwide that causes meningitis, septicemia, arthritis, and endocarditis. Using animal models, a surface-associated subtilisin-like protease (SspA) has recently been shown to be an important virulence factor for S. suis. In this study, we hypothesized that the S. suis SspA subtilisin-like protease may modulate cytokine secretion by macrophages thus contributing to the pathogenic process of meningitis. RESULTS: Phorbol 12-myristate 13-acetate-differentiated U937 macrophages were stimulated with recombinant SspA prior to monitor cytokine secretion by ELISA. Our results indicated that the recombinant SspA was able to dose-dependently induce IL-1ß, IL-6, TNF-α, CXCL8 and CCL5 secretion in macrophages. The heat-inactivated protease was still able to induce cytokine secretion suggesting a non-proteolytic mechanism of macrophage activation. Using specific kinase inhibitors, evidence were bought that cytokine secretion by macrophages stimulated with the recombinant SspA involves the mitogen-activated protein kinase signal transduction pathway. While stimulation of macrophages with low concentrations of recombinant SspA was associated to secretion of high amounts of CCL5, the use of recombinant SspA at a high concentration resulted in low amounts of CCL5 detected in the conditioned medium. This was found to be associated with a proteolytic degradation of CCL5 by SspA. The ability of SspA to induce cytokine secretion in macrophages was confirmed using a mutant of S. suis deficient in SspA expression. CONCLUSION: In conclusion, this study identified a new mechanism by which the S. suis SspA may promote central nervous system inflammation associated with meningitis.

Occurrence of Salmonella in the Cattle Production in France.

Salmonella is among the most common foodborne pathogens worldwide, and can lead to acute gastroenteritis. Along with poultry, cattle production is recognized as an important source of human infection. Salmonella transmission from cattle to humans can occur through the environment, or through close contact with sick animals or their derived products. This study aimed to investigate the intestinal carriage of Salmonella spp. within French cattle production. A total of 959 cattle intestinal samples, from one of the largest French slaughterhouses, were analyzed. Isolated strains were genotyped by pulsed field gel electrophoresis (PFGE), and a sub-selection was taken by whole genome sequencing (WGS). Twenty-nine samples were positive for Salmonella spp., yielding an estimated prevalence of 3% in cattle production. Eight different Salmonella serotypes were found: Montevideo was the most prevalent (34%), followed by Mbandaka (24%) and Anatum (14%). PFGE genotyping allowed the clustering of Salmonella isolates according to their serotype. Within the clusters, some isolates presented 100% similarity. To investigate potential epidemiological links between them, WGS and core genome multilocus sequence typing (cgMLST) were used, revealing identical profiles between isolates originating from different areas and/or different animal breeds. This investigation provides new insights on Salmonella serotype epidemiology in cattle production in France.

Closed Genome Sequence of a Salmonella enterica Serovar Bovismorbificans Strain Isolated from Dried Pork Sausage Associated with an Outbreak in France.

We report here the closed genome sequence of one Salmonella enterica subsp. enterica serovar Bovismorbificans strain isolated from dried pork sausage consumed by a patient suffering from salmonellosis.

The cell envelope subtilisin-like proteinase is a virulence determinant for Streptococcus suis.

BACKGROUND: Streptococcus suis is a major swine pathogen and zoonotic agent that mainly causes septicemia, meningitis, and endocarditis. It has recently been suggested that proteinases produced by S. suis (serotype 2) are potential virulence determinants. In the present study, we screened a S. suis mutant library created by the insertion of Tn917 transposon in order to isolate a mutant deficient in a cell surface proteinase. We characterized the gene and assessed the proteinase for its potential as a virulence factor. RESULTS: Two mutants (G6G and M3G) possessing a single Tn917 insertion were isolated. The affected gene coded for a protein (SSU0757) that shared a high degree of identity with Streptococccus thermophilus PrtS (95.9%) and, to a lesser extent, with Streptococcus agalactiae CspA (49.5%), which are cell surface serine proteinases. The SSU0757 protein had a calculated molecular mass of 169.6 kDa and contained the catalytic triad characteristic of subtilisin family proteinases: motif I (Asp200), motif II (His239), and motif III (Ser568). SSU0757 also had the Gram-positive cell wall anchoring motif (Leu-Pro-X-Thr-Gly) at the carboxy-terminus, which was followed by a hydrophobic domain. All the S. suis isolates tested, which belonged to different serotypes, possessed the gene encoding the SSU0757 protein. The two mutants devoid of subtilisin-like proteinase activity had longer generation times and were more susceptible to killing by whole blood than the wild-type parent strain P1/7. The virulence of the G6G and M3G mutants was compared to the wild-type strain in the CD1 mouse model. Significant differences in mortality rates were noted between the P1/7 group and the M3G and G6G groups (p < 0.001). CONCLUSION: In summary, we identified a gene coding for a cell surface subtilisin-like serine proteinase that is widely distributed in S. suis. Evidences were brought for the involvement of this proteinase in S. suis virulence.

Cranberry polyphenols: potential benefits for dental caries and periodontal disease.

Over the past decade, cranberries and their molecular components have received increasing attention from researchers in human health. In particular, the properties of the high-molecular-weight polyphenols isolated from cranberries have shown promise with regard to dental caries and periodontal disease. These potential anticaries agents inhibit the production of organic acids and the formation of biofilms by cariogenic bacteria. In addition, cranberry polyphenols may reduce the inflammatory response, as well as the production and activity of proteolytic enzymes contributing to the destruction of the extracellular matrix in periodontal disease. The polyphenols of cranberries also interfere with various activities (including formation of biofilm and adhesion) of Porphyromonas gingivalis, the main etiologic agent in chronic periodontitis. This article summarizes the scientific evidence supporting the potential of cranberry polyphenols to prevent and/or treat diseases of the mouth.

Epidemiological and Bacteriological Investigations Using Whole-Genome Sequencing in a Recurrent Outbreak of Pullorum Disease on a Quail Farm in France.

An outbreak of pullorum disease causing septicemia and high mortality was diagnosed in 2019 on a quail farm in western France. An initial episode had been detected in another building at the same site eight months earlier. Given the exceptional nature and the extent of the potential economic consequences of pullorum disease, epidemiological and bacteriological investigations using molecular sequencing tools were carried out. Salmonella Gallinarum and Salmonella Infantis were isolated (using the NF U 47-101 reference method) from samples taken from birds at the infected site. A resurgence of the initial episode by horizontal transmission of S. Gallinarum is the most likely hypothesis, supported by whole-genome sequencing (WGS) of the strains isolated during the two episodes. Risk health practices have been identified, including the rearing of animals of different ages and species on the same site. Recurrence is explained by the probable persistence of reservoirs of the pathogen on the site (manure, lesser mealworm beetles). The article also highlights the importance of decontamination measures, including pest control, as a key element in the success of the disease control protocol.

Probiotics for oral health: myth or reality?

For some decades now, bacteria known as probiotics have been added to various foods because of their beneficial effects for human health. The mechanism of action of probiotics is related to their ability to compete with pathogenic microorganisms for adhesion sites, to antagonize these pathogens or to modulate the host"s immune response. The potential application of probiotics for oral health has recently attracted the attention of several teams of researchers. Although only a few clinical studies have been conducted so far, the results to date suggest that probiotics could be useful in preventing and treating oral infections, including dental caries, periodontal disease and halitosis. This article summarizes the currently available data on the potential benefits of probiotics for oral health.

Fibrinogen induces biofilm formation by Streptococcus suis and enhances its antibiotic resistance.

In this study, we showed that supplementing the culture medium with fibrinogen induced biofilm formation by Streptococcus suis in a dose-dependent manner. Biofilm-grown S. suis cells were much more resistant to penicillin G than planktonic cells. S. suis bound fibrinogen to its surface, a property that likely contributes to biofilm formation.

A next generation sequencing approach with a suitable bioinformatics workflow to study fungal diversity in bioaerosols released from two different types of composting plants.

Composting is used all over the world to transform different types of organic matter through the actions of complex microbial communities. Moving and handling composting material may lead to the emission of high concentrations of bioaerosols. High exposure levels are associated with adverse health effects among compost industry workers. Fungal spores are suspected to play a role in many respiratory illnesses. There is a paucity of information related to the detailed fungal diversity in compost as well as in the aerosols emitted through composting activities. The aim of this study was to analyze the fungal diversity of both organic matter and aerosols present in facilities that process domestic compost and facilities that process pig carcasses. This was accomplished using a next generation sequencing approach that targets the ITS1 genomic region. Multivariate analyses revealed differences in the fungal community present in samples coming from compost treating both raw materials. Furthermore, results show that the compost type affects the fungal diversity of aerosols emitted. Although 8 classes were evenly distributed in all samples, Eurotiomycetes were more dominant in carcass compost while Sordariomycetes were dominant in domestic compost. A large diversity profile was observed in bioaerosols from both compost types showing the presence of a number of pathogenic fungi newly identified in bioaerosols emitted from composting plants. Members of the family Herpotrichiellaceae and Gymnoascaceae which have been shown to cause human diseases were detected in compost and air samples. Moreover, some fungi were identified in higher proportion in air compared to compost. This is the first study to identify a high level of fungal diversity in bioaerosols present in composting plants suggesting a potential exposure risk for workers. This study suggests the need for creating guidelines that address human exposure to bioaerosols. The implementation of technical and organizational measure should be a top priority. However, skin and respiratory protection for compost workers could be used to reduce the exposure as a second resort.