Effects of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans on Modeling Subgingival Microbiome and Impairment of Oral Epithelial Barrier.

Periodontitis is an exemplar of dysbiosis associated with the coordinated action of multiple members within the microbial consortium. The polymicrobial synergy and dysbiosis hypothesis proposes a dynamic host-microbiome balance, with certain modulators capable of disrupting eubiosis and driving shifts towards dysbiosis within the community. However, these factors remain to be explored. We established a Porphyromonas gingivalis- or Aggregatibacter actinomycetemcomitans-modified subgingival microbiome model and 16S rRNA sequencing revealed that P. gingivalis and A. actinomycetemcomitans altered the microbiome structure and composition indicated by α and ß diversity metrics. P. gingivalis increased the subgingival dysbiosis index (SDI), while A. actinomycetemcomitans resulted in a lower SDI. Furthermore, P. gingivalis-stimulated microbiomes compromised epithelium function and reduced expression of tight junction proteins, whereas A. actinomycetemcomitans yielded mild effects. In conclusion, by inoculating P. gingivalis, we created dysbiotic microcosm biofilms in vitro resembling periodontitis-related subgingival microbiota, exhibiting enhanced dysbiosis and impaired epithelium integrity.

Association of pneumococcal conjugate vaccination with SARS-CoV-2 infection among older adult recipients of COVID-19 vaccines: a longitudinal cohort study.

BACKGROUND: Pneumococcal carriage is associated with increased acquisition and duration of SARS-CoV-2 infection among adults. While pneumococcal conjugate vaccines (PCVs) prevent carriage of vaccine-serotype pneumococci, their potential impact on COVID-19 related outcomes remains poorly understood in populations with prevalent immunity against SARS-CoV-2. METHODS: We undertook a retrospective cohort study of adults aged ≥65 years in the Kaiser Permanente Southern California (KPSC) healthcare system who had received ≥2 COVID-19 vaccine doses, comparing risk of SARS-CoV-2 infection between 1 January, 2021 and 31 December, 2022 among recipients and non-recipients of PCV13. We estimated adjusted hazard ratios via Cox proportional hazards models, employing multiple strategies to mitigate bias from differential test-seeking behavior. RESULTS: The adjusted hazard ratio (aHR) of confirmed SARS-CoV-2 infection comparing PCV13 recipients to non-recipients was 0.92 (95% confidence interval: 0.90-0.95), corresponding to prevention of 3.9 (2.6-5.3) infections per 100 person-years. Following receipt of 2, 3, and ≥4 COVID-19 vaccine doses, aHRs were 0.85 (0.81-0.89), 0.94 (0.90-0.97), and 0.99 (0.93-1.04), respectively. The aHR for persons who had not received COVID-19 vaccination in the preceding 6 months was 0.90 (0.86-0.93), versus 0.94 (0.91-0.98) within 6 months after receipt of any dose. Similarly, the aHR was 0.92 (0.89-0.94) for persons without history of documented SARS-CoV-2 infection, versus 1.00 (0.90-1.12) for persons with documented prior infection. CONCLUSIONS: Among older adults who had received ≥2 COVID-19 vaccine doses, PCV13 was associated with modest protection against SARS-CoV-2 infection. Protective effects of PCV13 were greater among individuals expected to have weaker immune protection against SARS-CoV-2 infection.

The growth-stimulating factor of Treponema phagedenis from bovine digital dermatitis lesions.

Bovine digital dermatitis (BDD) is an infectious skin disease of the hoof characterized by painful ulcerations that cause lameness in dairy cattle. Cell-free supernatants (CFS) of Falsiporphyromonas endometrii predominantly isolated from BDD lesions had the highest growth-stimulating effect on Treponema phagedenis among BDD-associated bacteria. Butyric acid was detected at a concentration of 45.4 mM in CFS of F. endometrii, and the growth of T. phagedenis was significantly promoted by butyric acid supplementation.

Etiology and antimicrobial resistance patterns in chronic osteomyelitis of the tibia: an 11-year clinical experience.

PURPOSE: To analyze changes in tendency of etiology and of antimicrobial resistance patterns to most common local and systemic antibiotics in chronic osteomyelitis of the tibia (COM-T) in a Level I trauma center over an 11-year period. METHODS: A retrospective review including all patients with COM-T who were surgically treated from January 2009 to December 2019. Patients were divided into two period groups: 2009-2014 and 2015-2019. Microbiologic etiology was analyzed. Bacterial resistance patterns evaluation was based on the Magiorakos et al. classification, including proportions of multidrug-resistant organisms (MDROs, acquired non-susceptibility to at least one agent in three or more antimicrobial categories), extensively drug-resistant (XDR) and pan drug-resistant (PDR) organisms encountered. RESULTS: A total of 173 episodes of COM-T were identified. Monomicrobial infections represented 47.4% of all cases, while 28.3% had polymicrobial infections. Negative deep-bone cultures were identified in 24.3% of the patients. The most commonly isolated microorganisms were coagulase-negative Staphylococci (24.5%) and S. aureus (20.5%). No differences were found when comparing Gram-positive infections between periods (58.3% for 2009-2014 vs. 46.7% for 2015-2019; p = 0.10). Findings were similar for Gram-negative infections (37% vs. 33.7%; p = 0.62), although more polymicrobial infections were detected (24.7% vs. 33.3%, respectively; p = 0.359). MDROs were involved in 15% of the cases, with an upward trend when comparing both periods (12.8% vs. 23.6%; p = 0.07). The most-used combination of local antibiotics-glycopeptide (vancomycin) plus aminoglycoside (gentamicin or tobramycin)-was met with low rates of resistance in the most frequently isolated microorganisms. CONCLUSION: According to the results of the present study, rates of Gram-positive and Gram-negative infections remained consistent during the two study periods, but with an upward trend in MDRO and polymicrobial infections detected. The local combination of a glycopeptide plus an aminoglycoside was effective in treating the most frequently isolated microorganisms.

Angular cheilitis-an oral disease with many facets.

Cheilitis is a common inflammatory disorder of the vermillion and adjacent skin of the lips. A special type is angular cheilitis. The disease has a mixed etiology, mostly with bacterial and fungal components. Angular cheilitis may be a clinical sign of an underlying disease. It has two age peaks: one during childhood and another in adults. It becomes more frequent with aging. Clinical presentation, differential diagnoses, and treatment are discussed. Angular cheilitis is of importance in primary care of patients, in geriatrics, dentistry, pediatrics, internal medicine, and in dermatology.

What came first, the virus or the egg: Innate immunity during viral coinfections.

Infections with any pathogen can be severe and present with numerous complications caused by the pathogen or the host immune response to the invading microbe. However, coinfections, also called polymicrobial infections or secondary infections, can further exacerbate disease. Coinfections are more common than is often appreciated. In this review, we focus specifically on coinfections between viruses and other viruses, bacteria, parasites, or fungi. Importantly, innate immune signaling and innate immune cells that facilitate clearance of the initial viral infection can affect host susceptibility to coinfections. Understanding these immune imbalances may facilitate better diagnosis, prevention, and treatment of such coinfections.

The polymicrobial infection affects the infection recurrence rate (not failure) in treating femoral and tibial bone defects with the Masquelet technique-a comparative retrospective analysis of 54 patients with mono- and polymicrobial infections.

INTRODUCTION: This study evaluated whether polymicrobial infection affects reoperation rates due to infection recurrence and treatment failure with the Masquelet technique in infected posttraumatic segmental bone defects of the femur and tibia. METHODS:  We retrospectively analyzed patients treated between 2012 and 2021 in two trauma referral centers. We evaluated demographic data, injury, treatment, infection recurrence, failures, and bone healing rates according to whether the infection was mono- or polymicrobial. After uni-bivariate analysis between patients with polymicrobial and monomicrobial infection, we identified the variables associated with infection recurrence and failure through multivariate analysis. RESULTS:  We analyzed 54 patients, 30 (55.55%) with tibial and 24 (44.44%) femoral segmental bone defects, with a mean follow-up of 41.7 ± 15.0 months. Forty-four (81.48%) presented monomicrobial, and 10 (18.51%) polymicrobial infections. Comparatively, the need for soft tissue reconstruction and the infection recurrence rate was significantly higher in patients with polymicrobial infections. There was no significant difference in the failure rate (20 vs. 6.81% p = 0.23). Multivariable logistic regression analysis identified the polymicrobial infection as the only independent variable associated with infection recurrence (Odds Ratio = 11.07; p = 0.0017). CONCLUSION:  Our analysis suggests that polymicrobial infection is associated with a higher risk of infection recurrence in treating the femur and tibia segmental bone defects with the Masquelet technique. This information can help surgeons to inform patients about this and give them a realistic expectation of the outcome and the possibility of reoperation.

Protection against lethal sepsis following immunization with Candida species varies by isolate and inversely correlates with bone marrow tissue damage.

Protection against lethal Candida albicans (Ca)/Staphylococcus aureus (Sa) intra-abdominal infection (IAI)-mediated sepsis can be achieved by a novel form of trained innate immunity (TII) involving Gr-1+ myeloid-derived suppressor cells (MDSCs) that are induced by inoculation (immunization) with low virulence Candida species [i.e., Candida dubliniensis (Cd)] that infiltrate the bone marrow (BM). In contrast, more virulent Candida species (i.e., C. albicans), even at sub-lethal inocula, fail to induce similar levels of protection. The purpose of the present study was to test the hypothesis that the level of TII-mediated protection induced by Ca strains inversely correlates with damage in the BM as a reflection of virulence. Mice were immunized by intraperitoneal inoculation with several parental and mutant strains of C. albicans deficient in virulence factors (hyphal formation and candidalysin production), followed by an intraperitoneal Ca/Sa challenge 14 d later and monitored for sepsis and mortality. Whole femur bones were collected 24 h and 13 d after immunization and assessed for BM tissue/cellular damage via ferroptosis and histology. While immunization with standard but not sub-lethal inocula of most wild-type C. albicans strains resulted in considerable mortality, protection against lethal Ca/Sa IAI challenge varied by strain was usually less than that for C. dubliniensis, with no differences observed between parental and corresponding mutants. Finally, levels of protection afforded by the Ca strains were inversely correlated with BM tissue damage (R 2 = -0.773). TII-mediated protection against lethal Ca/Sa sepsis induced by Candida strain immunization inversely correlates with BM tissue/cellular damage as a reflection of localized virulence.

Comparative genomics of clinical Stenotrophomonas maltophilia isolates reveals genetic diversity which correlates with colonization and persistence in vivo.

Stenotrophomonas maltophilia is a Gram-negative emerging opportunistic pathogen often present in people with respiratory diseases such as cystic fibrosis (CF). People with CF (pwCF) experience lifelong polymicrobial infections of the respiratory mucosa. Our prior work showed that Pseudomonas aeruginosa promotes persistence of S. maltophilia in mouse respiratory infections. As is typical for environmental opportunistic pathogens, S. maltophilia has a large genome and a high degree of genetic diversity. In this study, we evaluated the genomic content of S. maltophilia, combining short and long read sequencing to construct nearly complete genomes of 10 clinical isolates. The genomes of these isolates were then compared with all publicly available S. maltophilia genome assemblies, and each isolate was then evaluated for colonization/persistence in vivo, both alone and in coinfection with P. aeruginosa. We found that while the overall genome size and GC content were fairly consistent between strains, there was considerable variability in both genome structure and gene content. Similarly, there was significant variability in S. maltophilia colonization and persistence in experimental mouse respiratory infections in the presence or absence of P. aeruginosa. Ultimately, this study gives us a greater understanding of the genomic diversity of clinical S. maltophilia isolates, and how this genomic diversity relates to both interactions with other pulmonary pathogens and to host disease progression. Identifying the molecular determinants of infection with S. maltophilia can facilitate development of novel antimicrobial strategies for a highly drug-resistant pathogen.

Identification of contributing factors, microorganisms and antimicrobial resistance involved in the complication of diabetic foot ulcer treatment.

Diabetic foot ulcer (DFU) is a neurological and peripherical complication of diabetes with unknown etiology that is often associated with polymicrobial infections. The present study was conducted to investigate the contributing factors in 285 DFU patients, which included 200 patients with diabetic foot infections (DFI). Identification and characterization of infecting bacterial isolates were done followed by assessment of their pattern of susceptibility to commonly used antibiotics. Among the studied subjects, type 2 diabetes mellitus (T2DM), ulcer type, depth, grade, loss of sensation, infection type, affected foot, recurrence, smoking status, Body Mass Index (BMI), and obesity levels revealed significant disease risk association. Ulcer grades 1 and 2 were more common in males while grade 3 in females. Recurrent infections were significantly higher in females (P = 0.03). Diabetic duration, hyperglycemia, ulcer type, infection type and BMI were positively correlated with delayed wound healing. In DFI samples, 40.2% consisted of gram-negative bacteria, with Pseudomonas aeruginosa (37.5%) being the most common, while in the 60% gram-positive isolates Staphylococcus aureus (40.5%) was the predominant species. Staphylococcus epidermidis was found more frequently in females (P = 0.05). The isolated bacterial strains presented higher resistance against the tested antibiotics; however, ceftriaxone was effective against most of the pathogens. In the current study T2DM along with diabetes duration, obesity, ulcer severity with polymicrobial infection was found to play a strong role in DFI development, where gender predisposition was also observed in ulcer grade and infection. DFI was correlated with loss of sensation, infection type, affected foot, smoking status, BMI and obesity levels.

Characterization of periprosthetic environment microbiome in patients after total joint arthroplasty and its potential correlation with inflammation.

AIMS: Periprosthetic joint infection (PJI) is one of the most serious complications after total joint arthroplasty (TJA) but the characterization of the periprosthetic environment microbiome after TJA remains unknown. Here, we performed a prospective study based on metagenomic next-generation sequencing to explore the periprosthetic microbiota in patients with suspected PJI. METHODS: We recruited 28 patients with culture-positive PJI, 14 patients with culture-negative PJI, and 35 patients without PJI, which was followed by joint aspiration, untargeted metagenomic next-generation sequencing (mNGS), and bioinformatics analysis. Our results showed that the periprosthetic environment microbiome was significantly different between the PJI group and the non-PJI group. Then, we built a "typing system" for the periprosthetic microbiota based on the RandomForest Model. After that, the 'typing system' was verified externally. RESULTS: We found the periprosthetic microbiota can be classified into four types generally: "Staphylococcus type," "Pseudomonas type," "Escherichia type," and "Cutibacterium type." Importantly, these four types of microbiotas had different clinical signatures, and the patients with the former two microbiota types showed obvious inflammatory responses compared to the latter ones. Based on the 2014 Musculoskeletal Infection Society (MSIS) criteria, clinical PJI was more likely to be confirmed when the former two types were encountered. In addition, the Staphylococcus spp. with compositional changes were correlated with C-reactive protein levels, the erythrocyte sedimentation rate, and the synovial fluid white blood cell count and granulocyte percentage. CONCLUSIONS: Our study shed light on the characterization of the periprosthetic environment microbiome in patients after TJA. Based on the RandomForest model, we established a basic "typing system" for the microbiota in the periprosthetic environment. This work can provide a reference for future studies about the characterization of periprosthetic microbiota in periprosthetic joint infection patients.

Interspecies interactions in mixed-species biofilms formed by Enterococcus faecalis and gram-negative bacteria isolated from polymicrobial diabetic foot ulcers.

Diabetic foot ulcers (DFU) are exacerbated by bacterial colonisation. Here, a high prevalence of Enterococcus faecalis was observed in DFU patients from an Argentinean hospital. E. faecalis was frequently co-isolated with Escherichia coli, Morganella morganii, and Pseudomonas aeruginosa. The effect of interspecies interactions on bacterial growth was investigated in mixed-species macrocolony biofilms developed in Lubbock-Glc-agar. Similar cell counts were found for E. faecalis and M. morganii growing in mixed and single-species biofilms. An E. faecalis strain showed 1 Log higher cell counts in mixed biofilms with E. coli. Remarkably, E. faecalis strains showed 2 to 4 Log higher cell counts in mixed biofilms with P. aeruginosa. This effect was not observed in planktonic growth or biofilms developed in tryptic soy agar. The present findings reveal bacterial interactions that benefit E. faecalis in mixed-species biofilms, mainly with P. aeruginosa, in a medium that partially mimics the nutrients found in DFU.

Effectiveness of conservative instrumentation in root canal disinfection.

OBJECTIVES: The impact of conservative instrumentation on the disinfection of root canals with different curvatures has not yet been determined. This ex vivo study aimed to evaluate and compare the effect of conservative instrumentation with TruNatomy (TN) and Rotate and a conventional rotary system, ProTaper Gold (PTG), on root canal disinfection during chemomechanical preparation of straight and curved canals. MATERIALS AND METHODS: Ninety mandibular molars with straight (n = 45) and curved (n = 45) mesiobuccal root canals were contaminated with polymicrobial clinical samples. Teeth were divided into three subgroups (n = 14) according to the file systems and the curvature. Canals were instrumented with TN, Rotate, and PTG, respectively. Sodium hypochlorite and EDTA were used as irrigants. Intracanal samples were taken before (S1) and after (S2) instrumentation. Six uninfected teeth were used as negative controls. The bacterial reduction between S1 and S2 was measured by ATP assay, flow cytometry, and culture methods. Kruskal-Wallis and ANOVA tests were followed by the Duncan post hoc test (p < 0.05). RESULTS: Bacterial reduction percentages were similar for the three file systems in straight canals (p > 0.05). However, PTG showed a lower reduction percentage of intact membrane cells in flow cytometry than TN and Rotate (p = 0.036). For the curved canals, no significant differences were obtained (p > 0.05). CONCLUSION: Conservative instrumentation of straight and curved canals using TN and Rotate files resulted in similar bacterial reduction compared to PTG. CLINICAL RELEVANCE: The disinfection efficacy of conservative instrumentation is similar to conventional instrumentation in straight and curved root canals.

The Outcomes of Hip and Knee Fungal Periprosthetic Joint Infections: A Retrospective Cohort Study.

BACKGROUND: Fungal infections are a rare cause of periprosthetic joint infection (PJI), identified in 1% of all of these cases. Outcomes are not well-established due to small cohort sizes in the published literature. The aims of this study were to establish the patient demographics and infection-free survival of patients presenting to 2 high-volume revision arthroplasty centers who had fungal infection of either a hip or knee arthroplasty. We sought to identify risk factors for poor outcomes. METHODS: A retrospective analysis was performed of patients at 2 high-volume revision arthroplasty centers who had confirmed fungal PJI of the total hip arthroplasty (THA) and total knee arthroplasty (TKA). Consecutive patients treated between 2010 and 2019 were included. Patient outcomes were classified as infection eradication or persistence. A total of 67 patients who had 69 fungal PJI cases were identified. There were 47 cases involving the knee and 22 of the hip. Mean age at presentation was 68 years (THA mean 67, range 46 to 86) (TKA mean 69, range, 45 to 88). A history of sinus or open wound was present in 60 cases (89%) (THA 21 cases, TKA 39 cases). The median number of operations prior to the procedure at which fungal PJI was identified was 4 (range, 0 to 9), THA 5 (range, 3 to 9), and TKA 3 (range, 0 to 9). RESULTS: At a mean follow-up 34 months (range, 2 to 121), remission rates were 11 of 24 (45%) and 22 of 45 (49%) for hip and knee, respectively. There were 7 TKA (16%) and 1 THA cases (4%) that failed treatment resulting in amputations. During the study period, 7 THA and 6 TKA patients had died. Two deaths were directly attributable to PJI. Patient outcome was not associated with the number of prior procedures, patient comorbidities, or organisms. CONCLUSION: Eradication of fungal PJI is achieved in less than half of patients, and outcomes are comparable for TKA and THA. The majority of patients who have fungal PJI present with an open wound or sinus. No factors were identified that increase the risk of persistent infection. Patients who have fungal PJI should be informed of the poor outcomes.

Activation of TLRs Triggers GLP-1 Secretion in Mice.

The gastrointestinal tract constitutes a large interface with the inner body and is a crucial barrier against gut microbiota and other pathogens. As soon as this barrier is damaged, pathogen-associated molecular patterns (PAMPs) are recognized by immune system receptors, including toll-like receptors (TLRs). Glucagon-like peptide 1 (GLP-1) is an incretin that was originally involved in glucose metabolism and recently shown to be rapidly and strongly induced by luminal lipopolysaccharides (LPS) through TLR4 activation. In order to investigate whether the activation of TLRs other than TLR4 also increases GLP-1 secretion, we used a polymicrobial infection model through cecal ligation puncture (CLP) in wild-type and TLR4-deficient mice. TLR pathways were assessed by intraperitoneal injection of specific TLR agonists in mice. Our results show that CLP induces GLP-1 secretion both in wild-type and TLR4-deficient mice. CLP and TLR agonists increase gut and systemic inflammation. Thus, the activation of different TLRs increases GLP-1 secretion. This study highlights for the first time that, in addition to an increased inflammatory status, CLP and TLR agonists also strongly induce total GLP-1 secretion. Microbial-induced GLP-1 secretion is therefore not only a TLR4/LPS-cascade.

Interplay between Candida albicans and Lactic Acid Bacteria in the Gastrointestinal Tract: Impact on Colonization Resistance, Microbial Carriage, Opportunistic Infection, and Host Immunity.

Emerging studies have highlighted the disproportionate role of Candida albicans in influencing both early community assembly of the bacterial microbiome and dysbiosis during allergic diseases and intestinal inflammation. Nonpathogenic colonization of the human gastrointestinal (GI) tract by C. albicans is common, and the role of this single fungal species in modulating bacterial community reassembly after broad-spectrum antibiotics can be readily recapitulated in mouse studies. One of the most notable features of C. albicans-associated dysbiotic states is a marked change in the levels of lactic acid bacteria (LAB). C. albicans and LAB share metabolic niches throughout the GI tract, and in vitro studies have identified various interactions between these microbes. The two predominant LAB affected are Lactobacillus species and Enterococcus species. Lactobacilli can antagonize enterococci and C. albicans, while Enterococcus faecalis and C. albicans have been reported to exhibit a mutualistic relationship. E. faecalis and C. albicans are also causative agents of a variety of life-threatening infections, are frequently isolated together from mixed-species infections, and share certain similarities in clinical presentation-most notably their emergence as opportunistic pathogens following disruption of the microbiota. In this review, we discuss and model the mechanisms used by Lactobacillus species, E. faecalis, and C. albicans to modulate each other's growth and virulence in the GI tract. With multidrug-resistant E. faecalis and C. albicans strains becoming increasingly common in hospital settings, examining the interplay between these three microbes may provide novel insights for enhancing the efficacy of existing antimicrobial therapies.

Prevention of Coronavirus Disease 2019 Among Older Adults Receiving Pneumococcal Conjugate Vaccine Suggests Interactions Between Streptococcus pneumoniae and Severe Acute Respiratory Syndrome Coronavirus 2 in the Respiratory Tract.

BACKGROUND: While secondary pneumococcal pneumonia occurs less commonly after coronavirus disease 2019 (COVID-19) than after other viral infections, it remains unclear whether other interactions occur between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Streptococcus pneumoniae. METHODS: We probed potential interactions between these pathogens among adults aged ≥65 years by measuring associations of COVID-19 outcomes with pneumococcal vaccination (13-valent conjugate vaccine [PCV13] and 23-valent pneumococcal polysaccharide vaccine [PPSV23]). We estimated adjusted hazard ratios (aHRs) using Cox proportional hazards models with doubly robust inverse-propensity weighting. We assessed effect modification by antibiotic exposure to further test the biologic plausibility of a causal role for pneumococci. RESULTS: Among 531 033 adults, there were 3677 COVID-19 diagnoses, leading to 1075 hospitalizations and 334 fatalities, between 1 March and 22 July 2020. Estimated aHRs for COVID-19 diagnosis, hospitalization, and mortality associated with prior PCV13 receipt were 0.65 (95% confidence interval [CI], .59-.72), 0.68 (95% CI, .57-.83), and 0.68 (95% CI, .49-.95), respectively. Prior PPSV23 receipt was not associated with protection against the 3 outcomes. COVID-19 diagnosis was not associated with prior PCV13 within 90 days following antibiotic receipt, whereas aHR estimates were 0.65 (95% CI, .50-.84) and 0.62 (95% CI, .56-.70) during the risk periods 91-365 days and >365 days, respectively, following antibiotic receipt. CONCLUSIONS: Reduced risk of COVID-19 among PCV13 recipients, transiently attenuated by antibiotic exposure, suggests that pneumococci may interact with SARS-CoV-2.

Analysis of host-pathogen gene association networks reveals patient-specific response to streptococcal and polymicrobial necrotising soft tissue infections.

BACKGROUND: Necrotising soft tissue infections (NSTIs) are rapidly progressing bacterial infections usually caused by either several pathogens in unison (polymicrobial infections) or Streptococcus pyogenes (mono-microbial infection). These infections are rare and are associated with high mortality rates. However, the underlying pathogenic mechanisms in this heterogeneous group remain elusive. METHODS: In this study, we built interactomes at both the population and individual levels consisting of host-pathogen interactions inferred from dual RNA-Seq gene transcriptomic profiles of the biopsies from NSTI patients. RESULTS: NSTI type-specific responses in the host were uncovered. The S. pyogenes mono-microbial subnetwork was enriched with host genes annotated with involved in cytokine production and regulation of response to stress. The polymicrobial network consisted of several significant associations between different species (S. pyogenes, Porphyromonas asaccharolytica and Escherichia coli) and host genes. The host genes associated with S. pyogenes in this subnetwork were characterised by cellular response to cytokines. We further found several virulence factors including hyaluronan synthase, Sic1, Isp, SagF, SagG, ScfAB-operon, Fba and genes upstream and downstream of EndoS along with bacterial housekeeping genes interacting with the human stress and immune response in various subnetworks between host and pathogen. CONCLUSIONS: At the population level, we found aetiology-dependent responses showing the potential modes of entry and immune evasion strategies employed by S. pyogenes, congruent with general cellular processes such as differentiation and proliferation. After stratifying the patients based on the subject-specific networks to study the patient-specific response, we observed different patient groups with different collagens, cytoskeleton and actin monomers in association with virulence factors, immunogenic proteins and housekeeping genes which we utilised to postulate differing modes of entry and immune evasion for different bacteria in relationship to the patients' phenotype.

Subsequent infection differentially affects the proteome of Caenorhabditis elegans by abrogating the intestinal cell proliferation.

With a wide range of bacterial infections growing, it has become a big challenge to the research field to combat the newly emerging diseases. Immuno-compromised patients are vulnerable to opportunistic infections. P. mirabilis, an opportunistic pathogen infects the nematode when the immune system is compromised. In the present study, the C. elegans was pre-exposed to S. aureus for a short term, and then consecutively infected with P. mirabilis. The primary infection caused by S. aureus makes the immune system of C. elegans vulnerable making it easy for P. mirabilis to colonize efficiently during subsequent exposure, thereby stimulating the immune system of the nematode. In this study, the C. elegans exposed to the pathogens (S. aureus 4 h/P. mirabilis 40 h and S. aureus 8 h/P. mirabilis 60 h time points) showed a substantial difference in the banding patterns of SDS-PAGE gel, when compared to their respective OP50 fed controls. 2-DE identified a total of 235 proteins from all the time points which had >2 fold regulation. The regulated protein spots were identified by MALDI-ToF/ToF analysis and one common protein CDC-25.1 was found to be regulated in all the comparative time points. CDC-25.1 seemed to down regulate during subsequent infection and up regulate in single infection. The transcriptomic regulation of cdc-25.1 also reflects the protein regulation. In addition to it, survival assay in cdc-25.1 mutant nematodes confirm the susceptibility of host during subsequent infection.

Effective Treatment of Single-Stage Revision Using Intra-Articular Antibiotic Infusion for Polymicrobial Periprosthetic Joint Infection.

BACKGROUND: The treatment of polymicrobial periprosthetic joint infection (PJI) confronted distinct challenges. No reports have assessed the efficacy of local antibiotic delivery combined with 1-stage exchange in polymicrobial PJI. METHODS: Between January 2013 and December 2018, we retrospectively analyzed the data of 126 patients, including 19 polymicrobial PJIs and 107 monomicrobial PJIs, who underwent single-stage revision using intra-articular antibiotic infusion. The risk factors, microbiology, infection control rate, and clinical outcomes were compared between the 2 groups. RESULTS: Higher body mass index, presence of a sinus tract, and prior revisions were the risk factors for polymicrobial PJI. Isolation of Staphylococcus epidermidis, Streptococcus, Enterococcus, and Gram-negative pathogens was highly associated with polymicrobial PJI. Of the 19 polymicrobial PJIs, only 2 patients occurred infection recurrence, which is similar with the result of 6 of 107 patients in the monomicrobial PJI (P = .225). The Harris Hip Score of the polymicrobial group showed no difference from that of the monomicrobial group (78 vs 80; P = .181). Nevertheless, the polymicrobial group exhibited inferior Hospital for Special Surgery knee score relative to the monomicrobial group (77 vs 79; P = .017). CONCLUSION: With rational and targeted use of antibiotics, single-stage revision can effectively control polymicrobial infections, and achieve favorable outcomes similar to that in monomicrobial patients. However, this regimen is still needed to be further confirmed, especially in the infections with different microbial species simultaneously. Additionally, obese patients with a sinus tract and those who had prior revisions had a greater risk of polymicrobial PJI.