Production of tumor necrosis factor-α and interleukin-6 in whole blood stimulated by live Gram-negative and Gram-positive bacteria

ObjectiveTo investigate the production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) induced by live Gram-negative and Gram-positive bacteria in whole blood in vitro.MethodsIn all, 49 different isolates were studied. Each of the 49 different isolates was incubated for 4 h with whole blood at a ratio of one monocyte per 1-5 bacteria. Plasma was then separated and frozen, and the concentrations of TNF-α and IL-6 were measured by enzyme immunoassays.ResultsThere was a positive correlation between TNF-α and IL-6 values, r= 0.9. Gram-negative bacteria induced higher levels of both TNF-α and IL-6 than Gram-positive bacteria. Group G streptococci (GGS) induced higher levels of TNF-α than Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and group A streptococci (GAS). Klebsiella pneumoniae induced higher levels of TNF-α than Haemophilus influenzae, Escherichia coli and Neisseria meningitidis. GGS induced higher levels of IL-6 than Staphylococcus epidermidis, Staphylococcus aureus and GAS. When the relative amounts of cytokine induced by the strains were compared to serum concentrations measured on admission in patients with bacteremia caused by the same bacterial isolates there was no significant correlation.ConclusionSpecies- and strain-related differences in cytokine-inducing properties were found which may have significance in clinical infections

Related carbapenemase-producing Klebsiella isolates detected in both a hospital and associated aquatic environment in Sweden

Carbapenem antibiotics are one of the last-resort agents against multidrug-resistant (MDR) bacteria. The occurrence of carbapenemase-producing Enterobacteriaceae (CPE) in wastewater and aquatic environments is an indication of MDR bacteria in the community. This study evaluated CPE in aquatic environments and compared them to the local hospital isolates in Sweden. Phenotypic and genotypic analyses of antibiotic resistance of environmental and clinical CPE were performed. The relatedness of the isolates and possible clonal dissemination was evaluated using phylogenetic and phyloproteomic analysis. Klebsiella oxytoca carrying carbapenemase genes (blaVIM-1, blaIMP-29) were isolated from wastewater and the recipient river, while K. oxytoca (blaVIM-1) and Klebsiella pneumoniae (blaVIM-1, blaOXA-48, blaNDM-1, blaKPC-3) were isolated from patients at the local clinics or hospital. The K. oxytoca classified as sequence type 172 (ST172) isolated from the river was genotypically related to two clinical isolates recovered from patients. The similarity between environmental and clinical isolates suggests the dispersion of blaVIM-1 producing K. oxytoca ST172 from hospital to aquatic environment and the likelihood of its presence in the community. This is the first report of CPE in aquatic environments in Sweden; therefore, surveillance of aquatic and hospital environments for CPE in other urban areas is important to determine the major transfer routes in order to formulate strategies to prevent the spread of MDR bacteria

Prevalence and Diversity of Antibiotic Resistance Genes in Swedish Aquatic Environments Impacted by Household and Hospital Wastewater

Antibiotic-resistant Enterobacteriaceae and non-lactose fermenting Gram-negative bacteria are a major cause of nosocomial infections. Antibiotic misuse has fueled the worldwide spread of resistant bacteria and the genes responsible for antibiotic resistance (ARGs). There is evidence that ARGs are ubiquitous in non-clinical environments, especially those affected by anthropogenic activity. However, the emergence and primary sources of ARGs in the environment of countries with strict regulations for antibiotics usage are not fully explored. The aim of the present study was to evaluate the repertoire of ARGs of culturable Gram-negative bacteria from directionally connected sites from the hospital to the wastewater treatment plant (WWTP), and downstream aquatic environments in central Sweden. The ARGs were detected from genomic DNA isolated from a population of selectively cultured coliform and Gram-negative bacteria using qPCR. The results show that hospital wastewater was a reservoir of several class B β-lactamase genes such as blaIMP-1, blaIMP-2, and blaOXA-23, however, most of these genes were not observed in downstream locations. Moreover, β-lactamase genes such as blaOXA-48, blaCTX-M-8, and blaSFC-1, blaV IM-1, and blaV IM-13 were detected in downstream river water but not in the WWTP. The results indicate that the WWTP and hospital wastewaters were reservoirs of most ARGs and contribute to the diversity of ARGs in associated natural environments. However, this study suggests that other factors may also have minor contributions to the prevalence and diversity of ARGs in natural environments

Long-Term Sinonasal Carriage of Staphylococcus aureus and Anti-Staphylococcal Humoral Immune Response in Patients with Chronic Rhinosinusitis

We investigated Staphylococcus aureus diversity, genetic factors, and humoral immune responses against antigens via genome analysis of S. aureus isolates from chronic rhinosinusitis (CRS) patients in a long-term follow-up. Of the 42 patients who provided S. aureus isolates and serum for a previous study, 34 could be included for follow-up after a decade. Clinical examinations were performed and bacterial samples were collected from the maxillary sinus and nares. S. aureus isolates were characterized by whole-genome sequencing, and specific anti-staphylococcal IgG in serum was determined using protein arrays. S. aureus was detected in the nares and/or maxillary sinus at both initial inclusion and follow-up in 15 of the 34 respondents (44%). Three of these (20%) had S. aureus isolates from the same genetic lineage as at inclusion. A low number of single-nucleotide polymorphisms (SNPs) were identified when comparing isolates from nares and maxillary sinus collected at the same time point. The overall change of antibody responses to staphylococcal antigens over time showed great variability, and no correlation was found between the presence of genes encoding antigens and the corresponding anti-staphylococcal IgG in serum; thus our findings did not support a role, in CRS, of the specific S. aureus antigens investigated

Long-term sinonasal carriage of staphylococcus aureus and anti-staphylococcal humoral immune response in patients with chronic rhinosinusitis

We investigated Staphylococcus aureus diversity, genetic factors, and humoral immune responses against antigens via genome analysis of S. aureus isolates from chronic rhinosinusitis (CRS) patients in a long-term follow-up. Of the 42 patients who provided S. aureus isolates and serum for a previous study, 34 could be included for follow-up after a decade. Clinical examinations were performed and bacterial samples were collected from the maxillary sinus and nares. S. aureus isolates were characterized by whole-genome sequencing, and specific anti-staphylococcal IgG in serum was determined using protein arrays. S. aureus was detected in the nares and/or maxillary sinus at both initial inclusion and follow-up in 15 of the 34 respondents (44%). Three of these (20%) had S. aureus isolates from the same genetic lineage as at inclusion. A low number of single-nucleotide polymorphisms (SNPs) were identified when comparing isolates from nares and maxillary sinus collected at the same time point. The overall change of antibody responses to staphylococcal antigens over time showed great variability, and no correlation was found between the presence of genes encoding antigens and the corresponding anti-staphylococcal IgG in serum; thus our findings did not support a role, in CRS, of the specific S. aureus antigens investigated

Expert Opinion on Dose Regimen and Therapeutic Drug Monitoring for Long-Term Use of Dalbavancin: Expert Review Panel

Background: Dalbavancin is a lipoglycopeptide with a long elimination half-life, currently licensed for the treatment of acute bacterial skin and skin structure infections (ABSSSI) in adults. Dalbavancin's potential in treating off-label complex gram-positive infections is promising and real-world experience in treating such infections is growing. However, clear guidance on extended dosing regimens is lacking. Objectives: We aim to provide clear expert opinion based on recent pharmacokinetic literature and expert and real-world experience in infection areas that require >2 weeks of treatment. Methods: A single face-to-face meeting was held in September 2022 to collate expert opinion and present safety data of dalbavancin use in these clinical indications. A survey was completed by all authors on their individual experience with dalbavancin which highlighted the heterogeneity in the regimens used. Results: After review of the survey data and recent literature, we present expert panel proposals which accommodate different healthcare settings and resource availability, and centre around the length of treatment duration including up to, or exceeding, 6 weeks. To achieve adequate dalbavancin concentrations for up to 6 weeks, 3,000mg of dalbavancin should be given over 4 weeks for the agreed complex infections requiring >2 weeks treatment. Therapeutic drug monitoring (TDM) is advised for longer treatment durations and in case of renal failure. Specific dosing recommendations for other special populations require further investigation. Conclusions: These proposals based on expert opinion have been defined to encourage best practice with dalbavancin to optimise its administration beyond the current approved licenced dose across different healthcare settings

Molecular investigations on a chimeric strain of Staphylococcus aureus sequence type 80

A PVL-positive, methicillin-susceptible Staphylococcus aureus was cultured from pus from cervical lymphadenitis of a patient of East-African origin. Microarray hybridisation assigned the isolate to clonal complex (CC) 80 but revealed unusual features, including the presence of the ORF-CM14 enterotoxin homologue and of an ACME-III element as well as the absence of etD and edinB. The isolate was subjected to both, Illumina and Nanopore sequencing allowing characterisation of deviating regions within the strain´s genome. Atypical features of this strain were attributable to the presence of two genomic regions that originated from other S. aureus lineages and that comprised, respectively, 3% and 1.4% of the genome. One deviating region extended from walJ to sirB. It comprised ORF-CM14 and the ACME-III element. A homologous but larger fragment was also found in an atypical S. aureus CC1/ST567 strain whose lineage might have served as donor of this genomic region. This region itself is a chimera comprising fragments from CC1 as well as fragments of unknown origin. The other deviating region comprised the region from htsB to ecfA2, i.e., another 3% of the genome. It was very similar to CC1 sequences. Either this suggests an incorporation of CC1 DNA into the study strain, or alternatively a recombination event affecting “canonical” CC80. Thus, the study strain bears witness of several recombination events affecting supposedly core genomic genes. Although the exact mechanism is not yet clear, such chimerism seems to be an additional pathway in the evolution of S. aureus. This could facilitate also a transmission of virulence and resistance factors and therefore offer an additional evolutionary advantage

Staphylococcus saccharolyticus Isolated From Blood Cultures and Prosthetic Joint Infections Exhibits Excessive Genome Decay

The slow-growing, anaerobic, coagulase-negative species Staphylococcus saccharolyticus is found on human skin and in clinical specimens but its pathogenic potential is unclear. Here, we investigated clinical isolates and sequenced the genomes of seven strains of S. saccharolyticus. Phylogenomic analyses showed that the closest relative of S. saccharolyticus is Staphylococcus capitis with an average nucleotide identity of 80%. Previously sequenced strains assigned to S. saccharolyticus are misclassified and belong to S. capitis. Based on single nucleotide polymorphisms of the core genome, the population of S. saccharolyticus can be divided into two clades that also differ in a few larger genomic islands as part of the flexible genome. An unexpected feature of S. saccharolyticus is extensive genome decay, with over 300 pseudogenes, indicating ongoing reductive evolution. Many genes of the core metabolism are not functional, rendering the species auxotrophic for several amino acids, which could explain its slow growth and need for fastidious growth conditions. Secreted proteins of S. saccharolyticus were determined; they include stress response proteins such as heat and oxidative stress-related factors, as well as immunodominant staphylococcal surface antigens and enzymes that can degrade host tissue components. The strains secrete lipases and a hyaluronic acid lyase. Hyaluronidase as well as urease activities were detected in biochemical assays, with clade-specific differences. Our study revealed that S. saccharolyticus has adapted its genome, possibly due to a recent change of habitat; moreover, the data imply that the species has tissue-invasive potential and might cause prosthetic joint infections

Erratum to: Frequency and typing of Propionibacterium acnes in prostate tissue obtained from men with and without prostate cancer

Background: Prostate cancer is the most common cancer among men in Western countries but the exact pathogenic mechanism of the disease is still largely unknown. An infectious etiology and infection-induced inflammation has been suggested to play a role in prostate carcinogenesis and Propionibacterium acneshas been reported as the most prevalent microorganism in prostatic tissue. We investigated the frequency and types of P. acnes isolated from prostate tissue samples from men with prostate cancer and from control patients without the disease. Methods: We included 100 cases and 50 controls in this study. Cases were men diagnosed with prostate cancer undergoing radical prostatectomy and controls were men undergoing surgery for bladder cancer without any histological findings of prostate cancer. Six biopsies taken from each patient’s prostate gland at the time of surgery were used for cultivation and further characterization of P. acnes. Results: The results revealed that P. acnes was more common in men with prostate carcinoma than in controls, with the bacteria cultured in 60 % of the cases vs. 26 % of the controls (p = 0.001). In multivariable analyses, men with P. acnes had a 4-fold increase in odds of a prostate cancer diagnosis after adjustment for age, calendar year of surgery and smoking status (OR: 4.46; 95 % CI: 1.93–11.26). To further support the biologic plausibility for a P. acnes infection as a contributing factor in prostate cancer development, we subsequently conducted cell-based experiments. P. acnes- isolates were co-cultured with the prostate cell line PNT1A. An increased cell proliferation and cytokine/chemokine secretion in infected cells was observed. Conclusion: The present study provides further evidence for a role of P. acnes in prostate cancer development