Identification of prosthetic joint infections with 16S amplicon metagenomic sequencing - comparison with standard cultivation approach

Prosthetic joint infections (PJIs) are commonly diagnosed via culture-based methods, which may miss hard-to-grow pathogens. This study contrasts amplicon metagenomic sequencing (16S AS) with traditional culture techniques for enhanced clinical decision-making. We analyzed sonicate fluid from 27 patients undergoing revision arthroplasty using both methods, emphasizing the distinction between contaminants and true positives. Our findings show moderate agreement between the two methods, with a Cohen's kappa of 0.490, varying across bacterial genera (Cohen's kappa -0.059 to 1). The sensitivity of 16S AS compared to culture was 81% (95% CI, 68% to 94%). Sequencing revealed greater microbial diversity, including anaerobic genera like Anaerococcus and Citrobacter. Interestingly, several culture-negative PJI samples showed diverse bacteria via 16S AS. Despite rigorous controls and algorithms to eliminate contaminants, confirming bacteria presence with 16S AS remains a challenge. This highlights the need for improved PJI diagnostic methods, while also pointing out the limitations of next-generation sequencing (NGS) as a clinical diagnostic tool.

Rapid Isothermal Detection of Pathogenic Clostridioides difficile Using Recombinase Polymerase Amplification

Nosocomial-associated diarrhea due to Clostridioides difficile infection (CDI) is diagnosed after sample precultivation by the detection of the toxins in enzyme immunoassays or via toxin gene nucleic acid amplification. Rapid and direct diagnosis is important for targeted treatment to prevent severe cases and recurrence. We developed two singleplex and a one-pot duplex fluorescent 15 min isothermal recombinase polymerase amplification (RPA) assays targeting the toxin genes A and B (tcdA and tcdB). Furthermore, we adapted the singleplex RPA to a 3D-printed microreactor device. Analytical sensitivity was determined using a DNA standard and DNA extracts of 20 C. difficile strains with different toxinotypes. Nineteen clostridial and gastrointestinal bacteria strains were used to determine analytical specificity. Adaptation of singleplex assays to duplex assays in a 50 μL volume required optimized primer and probe concentrations. A volume reduction by one-fourth (12.4 μL) was established for the 3D-printed microreactor. Mixing of RPA was confirmed as essential for optimal analytical sensitivity. Detection limits (LOD) ranging from 119 to 1411 DNA molecules detected were similar in the duplex tube format and in the singleplex 3D-printed microreactor format. The duplex RPA allows the simultaneous detection of both toxins important for the timely and reliable diagnosis of CDI. The 3D-printed reaction chamber can be developed into a microfluidic lab-on-a-chip system use at the point of care.

Non-human Clostridioides difficile Reservoirs and Sources: Animals, Food, Environment

Clostridioides difficile is ubiquitous and is found in humans, animals and in variety of environments. The substantial overlap of ribotypes between all three main reservoirs suggests the extensive transmissions. Here we give the overview of European studies investigating farm, companion and wild animals, food and environments including water, soil, sediment, wastewater treatment plants, biogas plants, air, and households. Studies in Europe are more numerous especially in last couple of years, but are still fragmented in terms of countries, animal species, or type of environment covered. Soil seem to be the habitat of divergent unusual lineages of C. difficile. But the most important aspect of animals and environment is their role in C. difficile transmissions and their potential as a source for human infection is discussed.

New treatment approaches for Clostridioides difficile infections: alternatives to antibiotics and fecal microbiota transplantation

Clostridioides difficile causes a range of debilitating intestinal symptoms that may be fatal. It is particularly problematic as a hospital-acquired infection, causing significant costs to the health care system. Antibiotics, such as vancomycin and fidaxomicin, are still the drugs of choice for C. difficile infections, but their effectiveness is limited, and microbial interventions are emerging as a new treatment option. This paper focuses on alternative treatment approaches, which are currently in various stages of development and can be divided into four therapeutic strategies. Direct killing of C. difficile (i) includes beside established antibiotics, less studied bacteriophages, and their derivatives, such as endolysins and tailocins. Restoration of microbiota composition and function (ii) is achieved with fecal microbiota transplantation, which has recently been approved, with standardized defined microbial mixtures, and with probiotics, which have been administered with moderate success. Prevention of deleterious effects of antibiotics on microbiota is achieved with agents for the neutralization of antibiotics that act in the gut and are nearing regulatory approval. Neutralization of C. difficile toxins (iii) which are crucial virulence factors is achieved with antibodies/antibody fragments or alternative binding proteins. Of these, the monoclonal antibody bezlotoxumab is already in clinical use. Immunomodulation (iv) can help eliminate or prevent C. difficile infection by interfering with cytokine signaling. Small-molecule agents without bacteriolytic activity are usually selected by drug repurposing and can act via a variety of mechanisms. The multiple treatment options described in this article provide optimism for the future treatment of C. difficile infection.

Genomic insights into antibiotic resistance and mobilome of lactic acid bacteria and bifidobacteria

Lactic acid bacteria (LAB) and Bifidobacterium sp. (bifidobacteria) can carry antimicrobial resistance genes (ARGs), yet data on resistance mechanisms in these bacteria are limited. The aim of our study was to identify the underlying genetic mechanisms of phenotypic resistance in 103 LAB and bifidobacteria using whole-genome sequencing. Sequencing data not only confirmed the presence of 36 acquired ARGs in genomes of 18 strains, but also revealed wide dissemination of intrinsic ARGs. The presence of acquired ARGs on known and novel mobile genetic elements raises the possibility of their horizontal spread. In addition, our data suggest that mutations may be a common mechanism of resistance. Several novel candidate resistance mechanisms were uncovered, providing a basis for further in vitro studies. Overall, 1,314 minimum inhibitory concentrations matched with genotypes in 92.4% of the cases; however, prediction of phenotype based on genotypic data was only partially efficient, especially with respect to aminoglycosides and chloramphenicol. Our study sheds light on resistance mechanisms and their transferability potential in LAB and bifidobacteria, which will be useful for risk assessment analysis.

SARS-CoV-2 molecular epidemiology in Slovenia, January to September 2021

BackgroundSequencing of SARS-CoV-2 PCR-positive samples was introduced in Slovenia in January 2021. Our surveillance programme comprised three complementary schemes: (A) non-targeted sequencing of at least 10% of samples, (B) sequencing of samples positive after PCR screening for variants of concern (VOC) and (C) sequencing as per epidemiological indication.AimWe present the analysis of cumulative data of the non-targeted surveillance of SARS-CoV-2 and variant-dependent growth kinetics for the five most common variants in Slovenia for the first 9 months of 2021.MethodsSARS-CoV-2 PCR-positive samples, from January to September 2021, were selected for sequencing according to the national surveillance plan. Growth kinetics studies were done on Vero E6 cells.ResultsAltogether 15,175 genomes were sequenced and 64 variants were detected, of which three successively prevailed. Variant B.1.258.17 was detected in ca 80% of samples in January and was replaced, within 9 weeks, by the Alpha variant. The number of cases decreased substantially during the summer of 2021. However, the introduction of the Delta variant caused a fourth wave and completely outcompeted other variants. Other VOC were only detected in small numbers. Infection of Vero E6 cells showed higher replication rates for the variants Alpha and Delta, compared with B.1.258.17, B.1.258, and B.1.1.70, which dominated in Slovenia before the introduction of the Alpha and Delta variants.ConclusionInformation on SARS-CoV-2 variant diversity provided context to the epidemiological data of PCR-positive cases, contributed to control of the initial spread of known VOC and influenced epidemiological measures.

Gut Microbiome Composition in Patients with Chronic Urticaria: A Review of Current Evidence and Data

Recent studies have linked gut microorganism composition and chronic urticaria (CU); however, the underlying mechanisms responsible for this connection are unknown. Since the human immune system is in homeostasis with microbiota, and the composition of the microbiome regulates the development and function of the immune system, it is likely that an alteration of microbiota components (a dysbiosis) could influence the course of chronic spontaneous urticaria (CSU), including disease severity, patient quality of life and treatment outcome. To date, several studies have identified changes in the gut microbiota composition of patients with CSU, though only a few have exhibited metabolic abnormalities associated with gut dysbiosis. The studies on CSU patients predominantly showed that the relative abundance of beneficial bacteria was decreased (Firmicutes and Bacteroides), while that of opportunistic bacteria was increased (Enterobacteria and Proteobacteria). In addition, serum metabolome analysis revealed that gut microbiota-associated alterations in unsaturated fatty acids and the butanoate metabolism pathway may play a role in CSU. These findings are potentially associated with inflammation mediated by the imbalance of Th1/Th2/Th17 cytokines, which might contribute to CSU pathogenesis. Further research in this field could improve clinical, diagnostic, and therapeutic approaches to patients with CSU. By applying new knowledge on gut microbial communities and metabolomics, future CSU therapies could modify the microbiota composition using agents such as probiotics or other similar agents, which, in combination with current standard therapies, could hopefully lead to a reduction in symptoms and an improved quality of life for CSU patients.

European survey on the current surveillance practices, management guidelines, treatment pathways and heterogeneity of testing of Clostridioides difficile, 2018-2019: results from The Combatting Bacterial Resistance in Europe CDI (COMBACTE-CDI)

BACKGROUND

Awareness and compliance with international guidelines for diagnosis and clinical management of Clostridioides difficile infection (CDI) are unknown.

AIM

To compare the awareness and compliance with the recommended strategies for diagnosis and clinical management of CDI across Europe in 2018-2019.

METHODS

Hospital sites and their associated community practices across 12 European countries completed an online survey in 2018-2019, to report on their practices in terms of surveillance, prevention, diagnosis, and treatment of CDI. Responses were collected from 105 hospitals and 39 community general practitioners (GPs).

FINDINGS

Hospital sites of 11 countries reported participation in national surveillance schemes compared with six countries for international schemes. The European Society of Clinical Microbiology and Infectious Diseases (ESCMID)-recommended CDI testing methodologies were used by 82% (86/105) of hospitals, however countries reporting the highest incidence of CDI used non-recommended tests. Over 75% (80/105) of hospitals were aware of the most recent European CDI treatment guidelines at the time of this survey compared with only 26% (10/39) of surveyed GPs. However, up to 15% (16/105) of hospitals reported using the non-recommended metronidazole for recurrent CDI cases, sites in countries with lower awareness of CDI treatment guidelines. Only 37% (39/105) of hospitals adopted contact isolation precautions in case of suspected CDI.

CONCLUSION

Good awareness of guidelines for the management of CDI was observed across the surveyed European hospital sites. However, low compliance with diagnostic testing guidelines, infection control measures for suspected CDI, and insufficient awareness of treatment guidelines continued to be reported in some countries.

Clostridioides difficile infection (CDI): A pan-European multi-center cost and resource utilization study, results from the Combatting Bacterial Resistance in Europe CDI (COMBACTE-CDI)

OBJECTIVES

Clostridioides difficile infection (CDI) is one of the leading nosocomial infections worldwide, resulting in a significantly increasing burden on the healthcare systems. However, Pan-European data about cost and resource utilization of CDI treatment do not exist.

METHODS

A retrospective analysis within the Combatting Bacterial Resistance in Europe CDI project was conducted based on resource costs for inpatient treatment and productivity costs. Country-specific cost values were converted to EURO referred to 1 January, 2019 values. Differences in price levels for healthcare services among the participating countries were adjusted by using an international approach of the Organisation for Economic Co-operation and Development. As the study focused on patients with recurrent CDI, the observed study population was categorized into (a) patients with CDI but without CDI recurrence (case group), (b) patients with CDI recurrence (recurrence group), and (c) patients without CDI (control group).

RESULTS

Overall, 430 hospitalized patients from 12 European countries were included into the analysis between July 2018 and November 2018. Distribution of mean hospital length of stay and mean overall costs per patient between the case group, recurrence group, and control group were as follows: 22 days (95% CI 17-27 days) vs. 55 days (95% CI 17-94 days) vs. 26 days (95% CI 22-31 days; p 0.008) and € 15 242 (95% CI 10 593-19 891) vs. € 52 024 (95% CI 715-103 334) vs. € 21 759 (95% CI 16 484-27 035; p 0.010), respectively. The CDI recurrence rate during the observational period was 18%. Change escalation in CDI medication (OR 3.735) and treatment in an intensive care unit (OR 5.454) were found to be the most important variables associated with increased overall costs of patients with CDI.

CONCLUSIONS

Treatment of patients with recurrent CDI results in a significant burden. Prevention of CDI recurrences should be in focus of daily patient care to identify the most cost-effective treatment strategy.

Children gut microbiota exhibits a different composition and metabolic profile after in vitro exposure to Clostridioides difficile and increases its sporulation

Clostridioides difficile (Clostridium difficile) infection (CDI) is one of the main public health concerns in adults, while children under 2 years of age are often colonized asymptomatically. In both adults and children, CDI is strongly associated with disturbances in gut microbiota. In this study, an in-vitro model of children gut microbiota was challenged with vegetative cells or a conditioned media of six different toxigenic C. difficile strains belonging to the ribotypes 027, 078, and 176. In the presence of C. difficile or conditioned medium the children gut microbiota diversity decreased and all main phyla (Bacteroidetes, Firmicutes, and Proteobacteria) were affected. The NMR metabolic spectra divided C. difficile exposed children gut microbiota into three clusters. The grouping correlated with nine metabolites (short chain fatty acids, ethanol, phenolic acids and tyramine). All strains were able to grow in the presence of children gut microbiota and showed a high sporulation rate of up to 57%. This high sporulation rate in combination with high asymptomatic carriage in children could contribute to the understanding of the reported role of children in C. difficile transmissions.

Broad host range may be a key to long-term persistence of bacteriophages infecting intestinal Bacteroidaceae species

The longitudinal studies have found that the human gut microbiota is stable over time with some major bacterial lineages or even strains persisting for years. This was recently extended to gut bacteriophages using the metagenomic data. Here, we focused on cultivation of the major Bacteroidetes of human gut, the Bacteroides and Phocaeicola strains, and their bacteriophages from two healthy donors. The persistence of Bacteroides and Phocaeicola species and strains was confirmed. We isolated 28 genetically different phages grouped into seven distinct clusters, two of these were new. Moreover, the bacteriophages from several groups, although being genetically quite homogeneous, had the ability to infect the strains belonging to different species isolated from several sampling time-points and different donors. We propose that the ability to infect several host species, which differ in their nutritional niches, may promote long-term persistence of dominant gut bacteriophage groups.

Low Clostridioides difficile positivity rate in wild animal shelter in Slovenia

Here we review literature on Clostridioides difficile in captive wild animals and describe results from a single wild animal shelter in Slovenia. C. difficile was found in four out of 22 samples from animals of 15 different species (mammals n = 3; birds n = 12). Isolates were cultured only from bird samples and typed as RT 078, 002, 014 and additional unknown type. All three known ribotypes are commonly shared between humans and/or animals and environment.

Gut community alterations associated with Clostridioides difficile colonization in hospitalized gastroenterological patients with or without inflammatory bowel disease

Clostridioides difficile colonization and development of infection commonly occur in inflammatory bowel disease (IBD) patients and can trigger flare-ups. Both conditions are inherently linked to disrupted gut microbiota. This study included 149 hospitalized gastrointestinal patients, which were divided into IBD (n = 48) and non-IBD patients (n = 101). Patients were tested for C. difficile colonization (qPCR and selective plating), and gut bacterial communities were analyzed with 16S amplicon sequencing. Blood test results were retrospectively collected from the medical records. IBD and non-IBD patients had comparable C. difficile colonization rates (31.7 and 33.3%, respectively). Compared to non-IBD C. difficile-non-colonized patients, IBD and C. difficile-colonized patients shared multiple common bacterial community characteristics including decreased diversity and reduced abundance of strict anaerobic bacteria. Furthermore, certain microbiota alterations were enhanced when IBD was accompanied by C. difficile colonization, indicating a synergistic effect between both medical complications. Conversely, certain microbial patterns were specific to C. difficile colonization, e.g., co-occurrence with Enterococcus, which was most common in IBD patients (81.3%).

Accuracy of Allplex SARS-CoV-2 assay amplification curve analysis for the detection of SARS-CoV-2 variant Alpha

Aim: To evaluate the accuracy of two PCR-based techniques for detecting SARS-CoV-2 variant Alpha (B.1.1.7). Materials & methods: A multicenter prospective cohort with 1137 positive specimens from Slovenia was studied. A mutation-based assay (rTEST-COVID-19 qPCR B.1.1.7 assay) and amplification curve pattern analysis of the Allplex SARS-CoV-2 assay were compared with whole-genome sequencing. Results: SARS-CoV-2 variant Alpha was detected in 155 samples (13.6%). Sensitivity and specificity were 98.1 and 98.0%, respectively, for the rTEST-COVID-19 qPCR B.1.1.7 assay and 97.4 and 97.5%, respectively, for amplification curve pattern analysis. Conclusion: The good analytical performance of both methods was confirmed for the preliminary identification of SARS-CoV-2 variant Alpha. This cost-effective principle for screening SARS-CoV-2 populations is also applicable to other emerging variants and may help to conserve some whole-genome sequencing resources.

A point-prevalence study on community and inpatient Clostridioides difficile infections (CDI): results from Combatting Bacterial Resistance in Europe CDI (COMBACTE-CDI), July to November 2018

BackgroundThere is a paucity of data on community-based Clostridioides difficile infection (CDI) and how these compare with inpatient CDI.AimTo compare data on the populations with CDI in hospitals vs the community across 12 European countries.MethodsFor this point-prevalence study (July-November 2018), testing sites sent residual diagnostic material on sampling days to a coordinating laboratory for CDI testing and PCR ribotyping (n = 3,163). Information on whether CDI testing was requested at the original site was used to identify undiagnosed CDI. We used medical records to identify differences between healthcare settings in patient demographics and risk factors for detection of C. difficile with or without free toxin.ResultsThe CDI positivity rate was 4.4% (country range: 0-16.2) in hospital samples, and 1.3% (country range: 0-2.2%) in community samples. The highest prevalence of toxinotype IIIb (027, 181 and 176) was seen in eastern European countries (56%; 43/77), the region with the lowest testing rate (58%; 164/281). Different predisposing risk factors were observed (use of broad-spectrum penicillins in the community (OR: 8.09 (1.9-35.6), p = 0.01); fluoroquinolones/cephalosporins in hospitals (OR: 2.2 (1.2-4.3), p = 0.01; OR: 2.0 (1.1-3.7), p = 0.02)). Half of community CDI cases were undetected because of absence of clinical suspicion, accounting for three times more undiagnosed adults in the community compared with hospitals (ca 111,000 vs 37,000 cases/year in Europe).ConclusionThese findings support recommendations for improving diagnosis in patients presenting with diarrhoea in the community, to guide good practice to limit the spread of CDI.

Clostridioides difficile positivity rate and PCR ribotype distribution on retail potatoes in 12 European countries, January to June 2018

Background

While human-to-human transmission of Clostridioides difficile occurs often, other infection sources, including food, animals and environment, are under investigation.

Aim

We present a large study on C. difficile in a food item in Europe, encompassing 12 European countries (Austria, France, Greece, Ireland, Italy, the Netherlands, Poland, Slovakia, Spain, Sweden, Romania and the United Kingdom).

Methods

Potato was selected because of availability, ease of sampling and high C. difficile positivity rates. Identical protocols for sampling and isolation were used, enabling a direct comparison of the C. difficile positivity rate.

Results

From C. difficile-positive potato samples (33/147; 22.4%), we obtained 504 isolates, grouped into 38 PCR ribotypes. Positivity rates per country varied (0–100%) and were at least 10% in 9/12 countries. No geographical clustering of samples with high positivity rates or in PCR ribotype distribution was observed. The most frequently detected PCR ribotypes (014/020, 078/126, 010 and 023) are also commonly reported in Europe among human clinically relevant isolates, in animal isolates and in the environment. Whole genome sequencing revealed several genetically related strain pairs (Spain/RT126, France/RT010, Austria and Sweden/RT276) and a cluster of very similar strains in RT078/126.

Conclusion

Our results suggest, the high potato contamination rates could have public health relevance. They indicate potatoes can serve as a vector for introducing C. difficile spores in the household environment, where the bacterium can then multiply in sensitive hosts with disrupted or unmature microbiota. Potato contamination with PCR ribotypes shared between humans, animals and soil is supportive of this view.

Identification of novel, cryptic Clostridioides species isolates from environmental samples collected from diverse geographical locations

Clostridioides difficile is a pathogen often associated with hospital-acquired infection or antimicrobial-induced disease; however, increasing evidence indicates infections can result from community or environmental sources. Most genomic sequencing of C. difficile has focused on clinical strains, although evidence is growing that C. difficile spores are widespread in soil and water in the environment. In this study, we sequenced 38 genomes collected from soil and water isolates in Flagstaff (AZ, USA) and Slovenia in an effort targeted towards environmental surveillance of C. difficile. At the average nucleotide identity (ANI) level, the genomes were divergent to C. difficile at a threshold consistent with different species. A phylogenetic analysis of these divergent genomes together with Clostridioides genomes available in public repositories confirmed the presence of three previously described, cryptic Clostridioides species and added two additional clades. One of the cryptic species (C-III) was almost entirely composed of Arizona and Slovenia genomes, and contained distinct sub-groups from each region (evidenced by SNP and gene-content differences). A comparative genomics analysis identified multiple unique coding sequences per clade, which can serve as markers for subsequent environmental surveys of these cryptic species. Homologues to the C. difficile toxin genes, tcdA and tcdB, were found in cryptic species genomes, although they were not part of the typical pathogenicity locus observed in C. difficile, and in silico PCR suggested that some would not amplify with widely used PCR diagnostic tests. We also identified gene homologues in the binary toxin cluster, including some present on phage and, for what is believed to be the first time, on a plasmid. All isolates were obtained from environmental samples, so the function and disease potential of these toxin homologues is currently unknown. Enzymatic profiles of a subset of cryptic isolates (n=5) demonstrated differences, suggesting that these isolates contain substantial metabolic diversity. Antimicrobial resistance (AMR) was observed across a subset of isolates (n=4), suggesting that AMR mechanisms are intrinsic to the genus, perhaps originating from a shared environmental origin. This study greatly expands our understanding of the genomic diversity of Clostridioides. These results have implications for C. difficile One Health research, for more sensitive C. difficile diagnostics, as well as for understanding the evolutionary history of C. difficile and the development of pathogenesis.

Comparison Between Cultivation and Sequencing Based Approaches for Microbiota Analysis in Swabs and Biopsies of Chronic Wounds

Chronic wounds are a prominent health concern affecting 0.2% of individuals in the Western population. Microbial colonization and the consequent infection contribute significantly to the healing process. We have compared two methods, cultivation and 16S amplicon sequencing (16S-AS), for the characterization of bacterial populations in both swabs and biopsy tissues obtained from 45 chronic wounds. Using cultivation approach, we detected a total of 39 bacterial species, on average 2.89 per sample (SD = 1.93), compared to 5.9 (SD = 7.1) operational taxonomic units per sample obtained with 16S-AS. The concordance in detected bacteria between swab and biopsy specimens obtained from the same CWs was greater when using cultivation (58.4%) as compared to 16S-AS (25%). In the entire group of 45 biopsy samples concordance in detected bacterial genera between 16S-AS and cultivation-based approach was 36.4% and in swab samples 28.7%. Sequencing proved advantageous in comparison to the cultivation mainly in case of highly diverse microbial communities, where we could additionally detect numerous obligate and facultative anaerobic bacteria from genera Anaerococcus, Finegoldia, Porphyromonas, Morganella, and Providencia. Comparing swabs and biopsy tissues we concluded, that neither sampling method shows significant advantage over the other regardless of the method used (16S-AS or cultivation). In this study, chronic wound microbiota could be distributed into three groups based on the bacterial community diversity. The chronic wound surface area was positively correlated with bacterial diversity in swab specimens but not in biopsy tissues. Larger chronic wound surface area was also associated with the presence of Pseudomonas in both biopsy and swab specimens. The presence of Corynebacterium species at the initial visit was the microbial marker most predictive of the unfavorable clinical outcome after one-year follow-up visit.

Novel Siphoviridae Bacteriophages Infecting Bacteroides uniformis Contain Diversity Generating Retroelement

Intestinal phages are abundant and important components of gut microbiota, yet the isolated and characterized representatives that infect abundant gut bacteria are sparse. Here we describe the isolation of human intestinal phages infecting Bacteroidesuniformis. Bacteroides is one of the most common bacterial groups in the global human gut microbiota; however, to date not many Bacteroides specific phages are known. Phages isolated in this study belong to a novel viral genus, Bacuni, within the Siphoviridae family. Their genomes encode diversity-generating retroelements (DGR), which were shown in other bacteriophages to promote phage adaptation to rapidly changing environmental conditions and to broaden their host range. Three isolated phages showed 99.83% genome identity but one of them infected a distinct B. uniformis strain. The tropism of Bacuni phages appeared to be dependent on the interplay of DGR mediated sequence variations of gene encoding putative phage fimbrial tip proteins and mutations in host genes coding for outer-membrane proteins. We found prophages with up to 85% amino acid similarity over two-thirds of the Bacuni phage genome in the B. acidifaciens and Prevotella sp. genomes. Despite the abundance of Bacteroides within the human microbiome, we found Bacuni phages only in a limited subset of published gut metagenomes.

High contamination rates of shoes of veterinarians, veterinary support staff and veterinary students with Clostridioides difficile spores

Clostridioides difficile is often found in animals and their environment. However, not much has been reported on veterinary clinics environment in terms of the spore load, prevalence and PCR ribotype diversity. The aim of this study was to assess the prevalence of C. difficile on shoe soles of veterinarians, veterinary support staff and veterinary students at the Veterinary Faculty campus. Altogether, 50 shoe sole swabs were collected, and the positivity rates ranged from 86.7% in swabs from veterinarians to 100% in swabs from support staff and students. Non‐toxigenic and toxigenic strains representing toxinotypes 0, IV and XIX were isolated and distributed into 17 different PCR ribotypes, most common being 010, 014/020, SLO002 and 009. PCR ribotype 010 was the most prevalent and isolated from shoe soles sampled in 6/7 areas. Students' shoes had highest ribotype diversity (15/17 PCR ribotypes) but showed a low overlap with ribotype isolated from vets and support staff shoes. Veterinary students are likely the main vectors of C. difficile spores transmissions among veterinary teaching clinics and the hospital.

Latent brain infection with Moraxella osloensis as a possible cause of cerebral gliomatosis type 2: A case report

BACKGROUND

The gram-negative aerobic bacterium Moraxella osloensis is an opportunistic pathogen in brain tissues.

CASE SUMMARY

The gram-negative aerobic bacterium Moraxella osloensis was isolated from a patient’s brain tissue during a stereotactic biopsy.

CONCLUSION

This is the first report of a brain tissue infection with Moraxella osloensis possibly causing brain gliomatosis.

Comparative genomics of Clostridioides difficile toxinotypes identifies module-based toxin gene evolution

Clostridioides difficile is a common cause of nosocomial diarrhoea. Toxins TcdA and TcdB are considered to be the main virulence factors and are encoded by the PaLoc region, while the binary toxin encoded in the CdtLoc region also contributes to pathogenicity. Variant toxinotypes reflect the genetic diversity of a key toxin-encoding 19 kb genetic element (the PaLoc). Here, we present analysis of a comprehensive collection of all known major C. difficile toxinotypes to address the evolutionary relationships of the toxin gene variants, the mechanisms underlying the origin and development of variability in toxin genes and the PaLoc, and the relationship between structure and function in TcdB variants. The structure of both toxin genes is modular, composed of interspersed blocks of sequences corresponding to functional domains and having different evolutionary histories, as shown by the distribution of mutations along the toxin genes and by incongruences of domain phylogenies compared to overall C. difficile cluster organization. In TcdB protein, four mutation patterns could be differentiated, which correlated very well with the type of TcdB cytopathic effect (CPE) on cultured cells. Mapping these mutations to the three-dimensional structure of the TcdB showed that the majority of the variation occurs in surface residues and that point mutation at residue 449 in alpha helix 16 differentiated strains with different types of CPE. In contrast to the PaLoc, phylogenetic trees of the CdtLoc were more consistent with the core genome phylogenies, but there were clues that CdtLoc can also be exchanged between strains.

Ribotype Classification of Clostridioides difficile Isolates Is Not Predictive of the Amino Acid Sequence Diversity of the Toxin Virulence Factors TcdA and TcdB

Clostridioides (Clostridium) difficile is the most commonly recognized cause of infectious diarrhea in healthcare settings. Currently there is no vaccine to prevent initial or recurrent C. difficile infection (CDI). Two large clostridial toxins, TcdA and TcdB, are the primary virulence factors for CDI. Immunological approaches to prevent CDI include antibody-mediated neutralization of the cytotoxicity of these toxins. An understanding of the sequence diversity of the two toxins expressed by disease causing isolates is critical for the interpretation of the immune response to the toxins. In this study, we determined the whole genome sequence (WGS) of 478 C. difficile isolates collected in 12 countries between 2004 and 2018 to probe toxin variant diversity. A total of 44 unique TcdA variants and 37 unique TcdB variants were identified. The amino acid sequence conservation among the TcdA variants (≥98%) is considerably greater than among the TcdB variants (as low as 86.1%), suggesting that different selection pressures may have contributed to the evolution of the two toxins. Phylogenomic analysis of the WGS data demonstrate that isolates grouped together based on ribotype or MLST code for multiple different toxin variants. These findings illustrate the importance of determining not only the ribotype but also the toxin sequence when evaluating strain coverage using vaccine strategies that target these virulence factors. We recommend that toxin variant type and sequence type (ST), be used together with ribotype data to provide a more comprehensive strain classification scheme for C. difficile surveillance during vaccine development objectives.

Clostridioides difficile ribotype distribution in a large teaching hospital in Serbia

Background

The global epidemic of nosocomial diarrhea caused by Clostridioides (Clostridium) difficile started in 2000, with high mortality rates and emergence of a new hypervirulent strain NAP1/BI/027. The aim of this study was to assess the presence of ribotype 027 and other C. difficile ribotypes in a Serbian University Hospital, compare the temporal variability of ribotypes 3 years apart, as well as to compare clinical, demographic and laboratory characteristics and disease outcome among patients infected with 027 and non-027 ribotype. This was a prospective observational cohort study addressing 4-month intervals during 2014/2015 and 2017/2018.

Results

Ribotyping was performed in 64 non-duplicate C. difficile strains. Ribotype 027 was the most prevalent, and was detected in 53 (82.8%) patients (43/45 and 10/19 patients in 2014-2015 and 2017/2018, respectively). Other detected ribotypes were 001/072 in 4 (6.3%), 002 in 4 (6.3%), 014/020 in 2 (3.1%) and 176 in 1 (1.5%) patient. The percentage of the patients infected with ribotype 027 significantly decreased during the 3-year period, from 95.6 to 52.6% (p < 0.001). Ribotype 027 infection was associated with fluoroquinolone treatment more frequently than infection with other ribotypes [33 (62.3%) vs. 2 (18.2%), p = 0.010)]. A severe C. difficile infection was diagnosed more often in patients with the detected ribotype 027 compared to those infected with non-027 ribotypes (p = 0.006). No significant difference in the mortality and recurrence rates was found between the patients infected with ribotype 027 and those infected with other ribotypes [10/53 (18.8%) vs. 2/11 (18.2%), p = 0.708, and 10/35 (28.6%) vs. 0/2 (0%), p = 1.000, respectively].

Conclusion

Clostridium difficile ribotype 027 was the most prevalent ribotype among patients in a large Serbian hospital, but there is a clear decreasing trend.

Microbiota in vitro modulated with polyphenols shows decreased colonization resistance against Clostridioides difficile but can neutralize cytotoxicity

While the knowledge on gut microbiota - C. difficile interactions has improved over the years, the understanding of the underlying mechanisms providing colonization resistance as well as preventative measures against the infection remain incomplete. In this study the antibiotic clindamycin and polyphenol extracts from pomegranate and blueberries were used individually and in combination to modulate fecal microbial communities in minibioreactor arrays (MBRA). Modulated communities were inoculated with C. difficile (ribotype 027). Subsequent 7-day periodical monitoring included evaluation of C. difficile growth and activity of toxins TcdA and TcdB as well as analysis of MBRA bacterial community structure (V3V4 16 S metagenomics). Polyphenols affected multiple commensal bacterial groups and showed different synergistic and antagonistic effects in combination with clindamycin. Exposure to either clindamycin or polyphenols led to the loss of colonization resistance against C. difficile. The successful growth of C. difficile was most significantly correlated with the decrease in Collinsella and Lachnospiraceae. Additionally, we demonstrated that Clostridium sporogenes decreased the activity of both C. difficile toxins TcdA and TcdB. The feature was shown to be common among distinct C. sporogenes strains and could potentially be applicable as a non-antibiotic agent for the alleviation of C. difficile infection.

Clostridioides difficile in national food surveillance, Slovenia, 2015 to 2017

BackgroundClostridioides difficile is an important human and animal intestinal pathogen. Because of increasing indications of an association between C. difficile and food, in 2015, the Administration of the Republic of Slovenia for Food Safety, Veterinary Sector and Plant Protection (UVHVVR) included C. difficile in its national food surveillance.AimWe aim to report the results and experience with a nationwide and long-term testing of food for C. difficile as a part of a regular national food surveillance programme.MethodsRetail minced meat and meat preparations (beef, pork and poultry) were sampled within a three-year period, 2015 to 2017. Selected raw retail vegetables, leaf salads and root vegetables, and ready-to-eat salads were only sampled during 2016 and 2017. Seafood was only sampled in 2017.ResultsAltogether, 434 samples were tested, with 12 of 336 (3.6%) meat samples and 6 of 98 (6.1%) raw vegetables contaminated with C. difficile. Twelve of 18 recovered food isolates were toxigenic (toxinotypes 0, III, V, XII). The isolates belonged to 13 different PCR ribotypes, 001 being most common (5 isolates). Several food types with an increased potential of being contaminated with C. difficile were detected by surveillance.ConclusionThe three-year C. difficile testing within the national food surveillance revealed a low proportion of C. difficile-contaminated food and high genotype variability. Because the risk of C. difficile infection associated with C. difficile-contaminated food is unknown, no measures were recommended in the case of positive results.

Isolation of Clostridioides difficile from different outdoor sites in the domestic environment

Clostridioides difficile was isolated from 12 of 25 samples collected from the gardens of five individual houses and 132 isolates belonged to 12 PCR ribotypes. Compost material had the highest positivity rate and the highest PCR ribotype diversity in comparison to soil from vegetable and flower gardens. Isolated PCR ribotypes overlap with common human and animal types but also with divergent C. difficile lineages common for the soil environment.

Distinct Types of Gut Microbiota Dysbiosis in Hospitalized Gastroenterological Patients Are Disease Non-related and Characterized With the Predominance of Either Enterobacteriaceae or Enterococcus

Typical disease-associated microbiota changes are widely studied as potential diagnostic or therapeutic targets. Our aim was to analyze a hospitalized cohort including various gastroenterological pathologies in order to fine-map the gut microbiota dysbiosis. Bacterial (V3 V4) and fungal (ITS2) communities were determined in 121 hospitalized gastrointestinal patients from a single ward and compared to 162 healthy controls. Random Forest models implemented in this study indicated that the gut community structure is in most cases not sufficient to differentiate the subjects based on their underlying disease. Instead, hospitalized patients in our study formed three distinct disease non-related clusters (C1, C2, and C3), partially explained by antibiotic use. Majority of the subjects (cluster C1) closely resembled healthy controls, showing only mild signs of community disruption; most significantly decreased in this cluster were Faecalibacterium and Roseburia. The remaining two clusters (C2 and C3) were characterized by severe signs of dysbiosis; cluster C2 was associated with an increase in Enterobacteriaceae and cluster C3 by an increase in Enterococcus. According to the cluster affiliation, subjects also showed different degrees of inflammation, most prominent was the positive correlation between levels of C-reactive protein and the abundance of Enterococcus.

Evaluation of Human Milk Microbiota by 16S rRNA Gene Next-Generation Sequencing (NGS) and Cultivation/MALDI-TOF Mass Spectrometry Identification

The aim of the present study was to characterize human milk microbiota (HMM) with 16S rRNA gene amplicon next-generation sequencing and cultivation/matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) identification approaches. We analyzed 31 human milk samples from healthy Slovenian mothers. To check the accuracy of MALDI-TOF MS identification, several colonies representing most abundant genera and those, which could not be reliably identified by MALDI-TOF, were subjected to Sanger sequencing of their 16S rRNA gene. We showed that cultivation/MALDI-TOF MS was a suitable tool for culture-dependent determination of HMM. With both approaches, Staphylococcus and Streptococcus were found as predominant genera in HMM and the abundance of Staphylococcus was associated with decreased microbial diversity. In addition, we characterized factors that might influence HMM. The use of a breast pump was significantly associated with composition of HMM, lower microbial load, and higher abundance of cultivable staphylococci. Moreover, our study suggests that administration of probiotics to the suckling infant might influence HMM by increased abundance of lactobacilli and the presence of viable probiotic bacteria in human milk. However, since our study was observational with relatively small sample size, more targeted studies are needed to study possible transfer of probiotics to the mammary gland via an external route and the physiological relevance of these events.

Development and Implementation of Whole Genome Sequencing-Based Typing Schemes for Clostridioides difficile

Clostridioides difficile is an important nosocomial pathogen increasingly observed in the community and in different non-human reservoirs. The epidemiology and transmissibility of C. difficile has been studied using a variety of typing methods, including more recently developed whole-genome sequence (WGS) analysis that is becoming used routinely for bacterial typing worldwide. Here we review the schemes for WGS-based typing methods available for C. difficile and their applications in the field of human C. difficile infection (CDI). The two main approaches to discover genomic variations are single nucleotide variant (SNV) analysis and methods based on gene-by-gene comparisons (frequently called core genome or whole genome MLST, cgMLST, or wgMLST). SNV analysis currently provides the ultimate resolution, however, typing nomenclature and standardized methodology are missing. On the other hand, gene-by-gene approaches allow portability and standardized nomenclature, and are therefore becoming increasingly popular in bacterial epidemiology and outbreak investigation. Two commercial software packages (BioNumerics and Ridom SeqSphere+) and an open source database (EnteroBase) for allele and sequence type determination for C. difficile are currently available. Proof-of-concept WGS studies have already enabled advances in the investigation of the population structure of C. difficile species, microevolution within the epidemic strains, intercontinental transmission over time and in tracking of transmission events. WGS of clinical C. difficile isolates demonstrated a considerable genetic diversity suggesting diverse reservoirs for CDI. WGS was also shown to aid in resolving relapses and reinfections in recurrent CDI and has potential for use as a tool for assessing hospital infection prevention and control performance.

Proteotyping of Clostridioides difficile as Alternate Typing Method to Ribotyping Is Able to Distinguish the Ribotypes RT027 and RT176 From Other Ribotypes

Clostridioides difficile, a Gram-positive spore-forming bacterium, is the leading cause of nosocomial diarrhea worldwide and therefore a substantial burden to the healthcare system. During the past decade, hypervirulent PCR-ribotypes (RT) e.g., RT027 or RT176 emerged rapidly all over the world, associated with both, increased severity and mortality rates. It is thus of great importance to identify epidemic strains such as RT027 and RT176 as fast as possible. While commonly used diagnostic methods, e.g., multilocus sequence typing (MLST) or PCR-ribotyping, are time-consuming, proteotyping offers a fast, inexpensive, and reliable alternative solution. In this study, we established a MALDI-TOF-based typing scheme for C. difficile. A total of 109 ribotyped strains representative for five MLST clades were analyzed by MALDI-TOF. MLST, based on whole genome sequences, and PCR-ribotyping were used as reference methods. Isoforms of MS-detectable biomarkers, typically ribosomal proteins, were related with the deduced amino acid sequences and added to the C. difficile proteotyping scheme. In total, we were able to associate nine biomarkers with their encoding genes and include them in our proteotyping scheme. The discriminatory capacity of the C. difficile proteotyping scheme was mainly based on isoforms of L28-M (2 main isoforms), L35-M (4 main isoforms), and S20-M (2 main isoforms) giving rise to at least 16 proteotyping-derived types. In our test population, five of these 16 proteotyping-derived types were detected. These five proteotyping-derived types did not correspond exactly to the included five MLST-based C. difficile clades, nevertheless the subtyping depth of both methods was equivalent. Most importantly, proteotyping-derived clade B contained only isolates of the hypervirulent RT027 and RT176. Proteotyping is a stable and easy-to-perform intraspecies typing method and a promising alternative to currently used molecular techniques. It is possible to distinguish the group of RT027 and RT176 isolates from non-RT027/non-RT176 isolates using proteotyping, providing a valuable diagnostic tool.

MRSA diversity and the emergence of LA-MRSA in a large teaching hospital in Slovenia

The methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of a variety of infections in hospitals and the community. One of the most prominent changes in the MRSA epidemiology is the emergence of livestock-associated MRSA (LA-MRSA) strains in the human population. The aim of this study was to follow the MRSA epidemiology in a large teaching hospital during an 8-year time period (2006-2013). Altogether 519 MRSA, cultured from screening or clinical samples, were distributed into 77 spa types, of which three (t003 and t001, associated with CC5; and t015; associated with CC45) were the most common. LA-MRSA-associated spa types (t011, t034, t108, t899; associated with CC398) started to emerge in the year 2009 and continued to be found annually at a frequency from 3.9% to 12.7% of all MRSA strains examined. Only 6 of 27 LA-MRSA strains were associated with infections.

Clostridium (Clostridioides) difficile shedding by polar bears (Ursus maritimus) in the Canadian Arctic

Clostridium (Clostridioides) difficile has been identified in humans and a wide range of animal species, but there has been little study of remote animal populations with limited human contact. The objective of this study was to determine the prevalence and types of C. difficile in wild and captive polar bears (Ursus maritimus). Fecal samples were collected from two populations of wild polar bears in Nunavut Canada; M'Clintock Channel and Hudson Strait (Davis Strait or Foxe Basin), as well as from a facility (PBJ) in Churchill, Manitoba that temporarily houses nuisance polar bears and from captive bears in a zoological park. Enrichment culture was performed and isolates were characterized by ribotyping and toxinotyping. Clostridium difficile was isolated from 24/143 (16.8%) of samples; 18/120 (15%) wild bear samples, 4/7 (57%) from the PBJ and 2/16 (13%) samples from three zoo bears. The prevalence of C. difficile was significantly higher in bears that were housed at the PBJ vs wild bears (P = 0.0042), but there was no difference between wild bears from M'Clintock Channel (14/100, 14%) and those from Hudson Strait (4/20, 20%) (P = 0.50). Fourteen of the 24 (58%) isolates were toxigenic; 13/18 (72%) wild bear isolates, 0/4 PBJ isolate and 1/2 zoo isolates. Four toxigenic ribotypes were identified, with one that possessed tcdB and cdtA predominating. None of the toxigenic isolates were ribotypes that have been identified previously by the authors. There was no overlap in toxigenic ribotypes between the different populations. Clostridium difficile was not uncommonly identified in polar bears, with differences in type distribution amongst the different regions. The presence of strains that have not been identified in humans or domestic animals suggests that polar bears may be a natural reservoir of unique strains of this important bacterium.

Different host factors are associated with patterns in bacterial and fungal gut microbiota in Slovenian healthy cohort

Gut microbiota in a healthy population is shaped by various geographic, demographic and lifestyle factors. Although the majority of research remains focused on the bacterial community, recent efforts to include the remaining microbial members like viruses, archaea and especially fungi revealed various functions they perform in the gut. Using the amplicon sequencing approach we analysed bacterial and fungal gut communities in a Slovenian cohort of 186 healthy volunteers. In the bacterial microbiome we detected 253 different genera. A core microbiome analysis revealed high consistency with previous studies, most prominently showing that genera Faecalibacterium, Bacteroides and Roseburia regularly comprise the core community. We detected a total of 195 fungal genera, but the majority of these showed low prevalence and are likely transient foodborne contaminations. The fungal community showed a low diversity per sample and a large interindividual variability. The most abundant fungi were Saccharomyces cerevisiae and Candida albicans. These, along with representatives from genera Penicillium and Debaryomyces, cover 82% of obtained reads. We report three significant questionnaire-based host covariates associated with microbiota composition. Bacterial community was associated with age and gender. More specifically, bacterial diversity was increased with age and was higher in the female population compared to male. The analysis of fungal community showed that more time dedicated to physical activity resulted in a higher fungal diversity and lower abundance of S. cerevisiae. This is likely dependent on different diets, which were reported by participants according to the respective rates of physical activity.

Prevalence and Strain Characterization of Clostridioides (Clostridium) difficile in Representative Regions of Germany, Ghana, Tanzania and Indonesia - A Comparative Multi-Center Cross-Sectional Study

Clostridioides (Clostridium) difficile infections (CDI) are considered worldwide as emerging health threat. Uptake of C. difficile spores may result in asymptomatic carrier status or lead to CDI that could range from mild diarrhea, eventually developing into pseudomembranous colitis up to a toxic megacolon that often results in high mortality. Most epidemiological studies to date have been performed in middle- and high income countries. Beside others, the use of antibiotics and the composition of the microbiome have been identified as major risk factors for the development of CDI. We therefore postulate that prevalence rates of CDI and the distribution of C. difficile strains differ between geographical regions depending on the regional use of antibiotics and food habits. A total of 593 healthy control individuals and 608 patients suffering from diarrhea in communities in Germany, Ghana, Tanzania and Indonesia were selected for a comparative multi-center cross-sectional study. The study populations were screened for the presence of C. difficile in stool samples. Cultured C. difficile strains (n = 84) were further subtyped and characterized using PCR-ribotyping, determination of toxin production, and antibiotic susceptibility testing. Prevalence rates of C. difficile varied widely between the countries. Whereas high prevalence rates were observed in symptomatic patients living in Germany and Indonesia (24.0 and 14.7%), patients from Ghana and Tanzania showed low detection rates (4.5 and 6.4%). Differences were also obvious for ribotype distribution and toxin repertoires. Toxin A⁺/B⁺ ribotypes 001/072 and 078 predominated in Germany, whereas most strains isolated from Indonesian patients belonged to toxin A⁺/B⁺ ribotype SLO160 and toxin A^-/B⁺ ribotype 017. With 42.9–73.3%, non-toxigenic strains were most abundant in Africa, but were also found in Indonesia at a rate of 18.2%. All isolates were susceptible to vancomycin and metronidazole. Mirroring the antibiotic use, however, moxifloxacin resistance was absent in African C. difficile isolates but present in Indonesian (24.2%) and German ones (65.5%). This study showed that CDI is a global health threat with geographically different prevalence rates which might reflect distinct use of antibiotics. Significant differences for distributions of ribotypes, toxin production, and antibiotic susceptibilities were observed.

Interactions Between Clostridioides difficile and Fecal Microbiota in in Vitro Batch Model: Growth, Sporulation, and Microbiota Changes

Disturbance in gut microbiota is crucial for the development of Clostridioides difficile infection (CDI). Different mechanisms through which gut microbiota influences C. difficile colonization are known. However, C. difficile could also affect gut microbiota balance as previously demonstrated by cultivation of fecal microbiota in C. difficile conditioned medium. In current study, the interactions of C. difficile cells with gut microbiota were addressed. Three different strains (ribotypes 027, 014/020, and 010) were co-cultivated with two types of fecal microbiota (healthy and dysbiotic) using in vitro batch model. While all strains showed higher sporulation frequency in the presence of dysbiotic fecal microbiota, the growth was strain dependent. C. difficile either proliferated to comparable levels in the presence of dysbiotic and healthy fecal microbiota or grew better in co-culture with dysbiotic microbiota. In co-cultures with any C. difficile strain fecal microbiota showed decreased richness and diversity. Dysbiotic fecal microbiota was more affected after co-culture with C. difficile than healthy microbiota. Altogether, 62 OTUs were significantly changed in co-cultures of dysbiotic microbiota/C. difficile and 45 OTUs in co-cultures of healthy microbiota/C. difficile. However, the majority of significantly changed OTUs in both types of microbiota belonged to the phylum Firmicutes with Lachnospiraceae and Ruminococcaceae origin.

Zoonotic Transfer of Clostridium difficile Harboring Antimicrobial Resistance between Farm Animals and Humans

The emergence of Clostridium difficile as a significant human diarrheal pathogen is associated with the production of highly transmissible spores and the acquisition of antimicrobial resistance genes (ARGs) and virulence factors. Unlike the hospital-associated C. difficile RT027 lineage, the community-associated C. difficile RT078 lineage is isolated from both humans and farm animals; however, the geographical population structure and transmission networks remain unknown. Here, we applied whole-genome phylogenetic analysis of 248 C. difficile RT078 strains from 22 countries. Our results demonstrate limited geographical clustering for C. difficile RT078 and extensive coclustering of human and animal strains, thereby revealing a highly linked intercontinental transmission network between humans and animals. Comparative whole-genome analysis reveals indistinguishable accessory genomes between human and animal strains and a variety of antimicrobial resistance genes in the pangenome of C. difficile RT078. Thus, bidirectional spread of C. difficile RT078 between farm animals and humans may represent an unappreciated route disseminating antimicrobial resistance genes between humans and animals. These results highlight the importance of the "One Health" concept to monitor infectious disease emergence and the dissemination of antimicrobial resistance genes.

The incidence of Clostridioides difficile and Clostridium perfringens netF-positive strains in diarrheic dogs

The aim of this study was to examine the incidence of Clostridioides (previously Clostridium) difficile and Clostridium perfringens in the feces of diarrheic and non-diarrheic dogs. Also, the presence of other common canine enteropathogens was examined. Toxigenic C. difficile and C. perfringens positive for the NetF-encoding gene (netF) were detected in 11 (11.9%) and seven (7.6%) diarrheic dogs, respectively. Three dogs were diagnosed simultaneously with toxigenic C. difficile and netF-positive C. perfringens. Among other enteropathogens, Giardia sp. was the most common agent detected in dogs positive for toxigenic C. difficile or netF-positive C. perfringens. The results suggest that C. difficile and C. perfringens occur more frequently as a primary cause of diarrhea.

Low overlap between carbapenem resistant Pseudomonas aeruginosa genotypes isolated from hospitalized patients and wastewater treatment plants

The variability of carbapenem-resistant Pseudomonas aeruginosa strains (CRPA) isolated from urine and respiratory samples in a large microbiological laboratory, serving several health care settings, and from effluents of two wastewater treatment plants (WWTP) from the same region was assessed by PFGE typing and by resistance to 10 antibiotics. During the 12-month period altogether 213 carbapenem-resistant P. aeruginosa isolates were cultured and distributed into 65 pulsotypes and ten resistance profiles. For representatives of all 65 pulsotypes 49 different MLSTs were determined. Variability of clinical and environmental strains was comparable, 130 carbapenem-resistant P. aeruginosa obtained from 109 patients were distributed into 38 pulsotypes, while 83 isolates from WWTPs were classified into 31 pulsotypes. Only 9 pulsotypes were shared between two or more settings (hospital or WWTP). Ten MLST were determined for those prevalent pulsotypes, two of them (ST111 and ST235) are among most successful CRPA types worldwide. Clinical and environmental carbapenem-resistant P. aeruginosa strains differed in antibiotic resistance. The highest proportion of clinical isolates was resistant to piperacillin/tazobactam (52.3%) and ceftazidime (42.3%). The highest proportion of environmental isolates was resistant to ceftazidime (37.1%) and ciprofloxacin (35.5%). The majority of isolates was resistant only to imipenem and/or meropenem. Strains with additional resistances were distributed into nine different patterns. All of them included clinically relevant strains, while environmental strains showed only four additional different patterns.