Frontiers in Cellular and Infection Microbiology
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Preprints posted in the last 30 days, ranked by how well they match Frontiers in Cellular and Infection Microbiology's content profile, based on 109 papers previously published here. The average preprint has a 0.11% match score for this journal, so anything above that is already an above-average fit.
Maust, B. S.; Griswold, K. A.; Khim, M.; Subramanian, S.; Staker, B.; Myler, P. J.; Kullin, B. R.; Happel, A.-U.; Varsani, A.; Jaspan, H. B.
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The Gardnerella genus includes a complex sub-taxonomy of bacterial species and subgroups which have been implicated in bacterial vaginosis. We analyzed G. leopoldii, G. swidsinski, G. piotii, and G. vaginalis genomes available in public databases and predicted proviral sequences using Cenote-Taker3. We clustered 266 prophage sequences into 140 viral genera level groupings that encode four distinct gene clusters and 19 different lysin proteins. Analysis of the bacterial and prophage sequence phylogenies reveals that while there were no specific prophage sequence lineages that infected each bacterial host, there is clustering of the prophage sequences by bacterial species within the Gardnerella genus.
Shi, X. C.; Olagoke, O.; Titiheruw, B. R.; Chung, S.; Mengistie, H. D.; Asfaha, K.; Read, T. D.; Dean, D.
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ABSTRACT Background: Trachoma remains the leading infectious cause of blindness. Over 100M people are at risk, and 1.9M already live with visual impairment or blindness. Ethiopia bears the greatest burden of disease with ~61M or 59% of the known affected global population. Although Chlamydia trachomatis (Ct) infection initiates disease, infection alone fails to explain why inflammation resolves in some but progresses to irreversible scarring and vision loss in others. Previous studies have largely examined gene expression or limited protein panels, leaving the conjunctival immune protein environment poorly characterized. We hypothesized that distinct conjunctival immune states capture these pathogenic processes and could reveal biomarkers for selecting treatment and surveillance strategies. Methods and Findings: We conducted a cross-sectional study of 667 participants residing in the hyperendemic Amhara region of Ethiopia at least one year after the most recent azithromycin mass drug administration to treat Ct. The upper tarsal conjunctivae was graded for TF and TI, trachomatous inflammation-follicular or intense, respectively; I-TS/TT, inflammation with scarring with or without trichiasis, defined as one or more eyelashes touching the globe of the eye; and TS and TT, scarring with or without trichiasis but no inflammation. T0 represented no trachoma. The protein concentrations of 41 immune mediators were quantified using Meso Scale Discovery electrochemiluminescence immunoassays. Associations with infection and grade were evaluated using covariate-adjusted models with false discovery rate correction. Bernoulli mixture modeling (BMM) revealed four distinct Immune State Types (ISTs). Both approaches supported a shared biological framework characterized by selective immune activation in Ct infection, broad inflammation in TF/TI, and chemokine remodeling versus immune quiescence in the scarred conjunctiva. Ct infection was associated with a focused IFN-{gamma}-centered response. IST1 captured this immune response where 51.9% of the participants had Ct; we therefore termed IST1 Quiescent Infection. In contrast, TF/TI was associated with higher concentrations of proinflammatory, Th1/Th17, chemokine, regulatory, and remodeling pathways mediators. This profile fit well within IST2, termed Broad Inflammation, where 72.4% of the participants had TF/TI. TS/TT retained considerable chemokine activity, whereas I-TS/TT showed a narrower, IL-17A-dominant inflammatory profile. BMM separated scarring into two states characterized by distinct profiles: IST3, Conjunctival Remodeling, with significantly stronger chemokine and T-cell maintenance signals; and IST4, Quiescent Scarring, with the majority of chemokines being significantly downregulated. This suggests that scarred conjunctiva can retain substantial immune activity or shift toward a more attenuated state. Conclusions: This study establishes the first IST framework for trachoma, revealing biologically distinct immune states with different potential clinical implications. IST1 indicates the need for antibiotic treatment, whereas IST2 suggests that novel immunotherapeutics might be effective in thwarting disease progression. The upregulated chemokines in IST3 may indicate risk of progression to TT necessitating prospective studies and potential novel antifibrotic interventions. Together, our findings provide a strong biological foundation for stratifying patients by immune state and matching them to preventive and therapeutic care. Prospective validation and streamlined biomarker panels will support the translation of this framework into field settings to help avert disease progression and blindness.
Govindarajan, R.; Gowri Sankar, S.; Rahi, M.; Philip Samuel, P.; Alwin Prem Anand, A.
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Orientia tsutsugamushi is the causative agent of scrub typhus infection in humans. This pathogen is transmitted into mammalian hosts including humans through Leptotrombidium mites. Till date, detection of O. tsutsugamushi in human was performed using PCR assay with 56kDa type specific antigen (TSA56), 47kDa outer membrane protein (47kDa-OMP) and groEL chaperonin gene. To understand the efficiency of different genes for the detection of O. tsutsugamushi in Leptotrombidium mites, we performed a comparative PCR assay with various universal primers targeting different genes including TSA56, 47kDa-OMP and groEL gene. We have collected 500 Leptotrombidium mites from Vellore, Tamil Nadu and, the mites were segregated into 50 pools with 10 mites in each pool were used for DNA extraction. The molecular detection of O. tsutsugamushi was performed using PCR assays (including conventional, nested and duplex PCR). The comparative PCR analysis showed nested PCR of groEL gene has high efficiency in detecting the presence of O. tsutsugamushi in chigger samples compared to other genes. Interestingly, groEL target demonstrated high efficiency for detection of O. tsutsugamushi in chigger samples and, when used with nested primers, can facilitate differentiation of O. tsutsugamushi from other rickettsial pathogens. Thus, we conclude groEL gene nested PCR assay can be used routinely to detect O. tsutsugamushi in trombiculid mites.
Novak, J.; Vik, V.; Drahos, M.; Langerova, A.; Thon, V.; Kratka, Z.
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Background: European Association of Urology (EAU) Guidelines identify urogenital infections as a possible treatable cause of infertility, yet the current recommendation for antibiotic treatment remains weak due to a lack of high-quality evidence. We evaluated the effect of antibiotic treatment of asymptomatic urogenital infections on both conventional and apoptosis-related (flow cytometry sperm apoptosis test, FACS-APO) sperm parameters, as well as on pregnancy outcomes, in infertile couples. Methods: In this retrospective, single-centre study, we analysed 265 couples with an asymptomatic urogenital infection (Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma genitalium, and Chlamydia trachomatis) confirmed in at least one partner by first-void urine testing, who received simultaneous antibiotic treatment. Paired conventional semen analysis and FACS-APO were performed before and 0-9 months after treatment completion. Partner infection concordance, the effect of follow-up timing on treatment response, and pregnancy outcomes within 12 months were also assessed. Results: Sperm concentration, total sperm count, total and progressive motility, and the proportion of viable sperm increased significantly after treatment, while the proportion of late apoptotic / necrotic sperm and calculated sperm DNA fragmentation decreased significantly (all p<0.05); the proportion of early apoptotic sperm remained unchanged, and semen volume did not change. Among 244 couples with complete bilateral microbiological testing, Ureaplasma urealyticum was by far the most prevalent pathogen (57.8% of men, 87.7% of women), and female partner positivity given male positivity was 83.0%. The improvement in sperm concentration and total sperm count was most pronounced within 3 months after treatment and diminished, or reversed, beyond 6 months. Pregnancy was achieved in 127 of 265 couples (47.9%; per-protocol rate 53.4%) within 12 months, most commonly following in vitro fertilization (72/127) or spontaneously (21/127). Conclusions: Antibiotic treatment of asymptomatic urogenital infections in infertile couples was associated with significant improvement in conventional semen parameters and a reduction in sperm apoptosis and calculated DNA fragmentation. Given the retrospective, uncontrolled design, these findings should be regarded as hypothesis-generating rather than definitive proof of a causal, fertility-enhancing effect, and warrant confirmation in prospective controlled studies.
Botchorichvili, H.; Massier, S.; Chassaing, B.; Birer, A.; Chevarin, C.; Sevrin, G.; Rodrigues, M.; Denis, S.; Wawrzyniak, I.; Peyretaillade, E.; Bonnet, R.; Pereira, B.; Allez, M.; Seksik, P.; Denizot, J.; The Remind Group, ; Buisson, A.; Journet, L.; Barnich, N.; BILLARD, E.
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Adherent Invasive Escherichia coli (AIEC) colonize the ileal mucosa of Crohn's disease patients. Among bacterial virulence factors potentially implicated, type 6 secretion systems (T6SS) are molecular machineries sending effectors in prokaryotic or eukaryotic target cells. Two T6SS have been reported in AIEC LF82 reference strain. Here, we show that T6SS genes are more prevalent in Crohn's disease patients' microbiota compared to healthy controls, and that T6SS are more frequent in AIEC pathovar compared to E. coli in general and associated with FimH pathoadaptive polymorphism. The use of an in vitro gastrointestinal system coupled with T6SS promoter reporter assay highlighted expression of LF82 T6SS under gastrointestinal conditions, with a major role for bile salts. In mice infected with AIEC LF82 versus T6SS-deleted mutants, T6SS showed a functional impact in modulating the composition of mucosa-associated gut microbiota. Thus, AIEC may use their T6SS to compete with endogenous microbiota to colonize host mucosa.
RUFFIOT, T.; HICHAM, S.; OLIVEIRA PAIVA, A.; LEGERET, B.; SENG, D.; LI-BEISSON, Y.; GOMPERTS BONECA, I.; BUDDELMEIJER, N.
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Pre-prolipoprotein phosphatidylglycerol diacylglyceryl transferase (Lgt) catalyzes the first step in the lipoprotein modification pathway and is essential for growth and viability of Helicobacter pylori. We explored the fate of H. pylori cells under Lgt depletion conditions to obtain insight into Lgt function on morphology and physiology. Downregulation of lgt expression led to growth arrest and a heterogenous population of small rod-shaped cells and small round cells with spiky protrusions, a loose outer membrane and disintegrated flagella. H. pylori overcomes a defect in lipoprotein modification through alteration of its gene expression profile resulting in so-called revertants. Outer membrane protein synthesis, carbon metabolism and nutrient uptake was reduced, and protein translation and flagellar biogenesis increased. Lgt specific regulation was observed in phospholipid biosynthesis resulting in an initial increase in cardiolipin followed by an increase in lysophospholipids at the time of adaptation. Suppressors of {Delta}lgt that were selected on solid media under restrictive conditions either lacked chromosomal mutations or had mutations in the cagUT-tetR regulon controlling the expression of lgt. A suppressor without mutations had an altered expression profile that led to downregulation of a DNA methyltransferase and upregulation of HP_0014, a motility associated glycosyltransferase family protein. Transmission electron microscopy and single cell video microscopy showed that a subpopulation of cells is motile in the revertant while the suppressor regained full motility with higher average speed compared to the wild type strain. Overall, our data show that lipoprotein modification by Lgt is important for membrane and flagellar integrity and that the heterogenous character of H. pylori cultures allows individual cells to overcome this cell envelope stress and survive. Our findings are important for antibacterial development strategies targeting essential integral membrane enzymes involved in lipoprotein modification and stimulate exploration of synergetic activity between known antibiotics and novel antibacterial agents targeting novel cellular pathways.
Lindon, A. K.; Pearah, A. N.; Dominguez, K.; John-Lewis Edwards, N.; Williams, O. M.; Natarajan, O.; Handel, R.; Zelaya Aparicio, C. N.; Dishaw, L. J.; Darch, S. E.; Randis, T. M.
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Background Group B Streptococcus (GBS) is a leading cause of bacterial sepsis globally. Late-onset (LO) GBS disease is preceded by colonization within the gastrointestinal tract in vulnerable neonates. Previous studies demonstrate that Candida albicans (C. albicans) promotes GBS colonization of host tissues including the bladder and vagina. However, its impact on GBS colonization of the intestinal tract is unknown. Methods We established a new animal model to study GBS and C. albicans co-colonization model in the context of the newborn host to examine C. albicans impact on GBS and further evaluated fluconazole prophylactic treatment to these same outcomes. Physical interactions between organisms in vivo were imaged and GBS gene expression was evaluated. Results C. albicans increased GBS burden in the neonatal gut and GBS was physically colocalized with C. albicans hyphae as evidenced by the colocalization analysis. Fluconazole treatment of co-colonized mice decreased extraintestinal GBS dissemination. C. albicans presence upregulated genes encoding proteins responsible for GBS adhesion and invasion of intestinal epithelial cells. Conclusion C. albicans enhances GBS burden and pathogenicity in the neonatal gut. These findings highlight the need for further investigation into C. albicans as a potential risk factor for GBS colonization and LO disease in human infants.
Gilliland, R.; Valdes-Tresanco, M. E.; Plakhotnyk, A.; Westlund, A.; Smith, J. T.; Pham, T. M.; Mortimer, T. D.; Walker, B. J.; Earl, A. M.; Grad, Y. H.; MacDonald, M. E.; Lewis, I. A.; PRIME Consortium,
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Bloodstream infection (BSI) is a life-threatening condition where the risk of dying is affected by both patient- and pathogen-related factors. Certain microbial traits (e.g., virulence genes) are thought to affect survival rates from BSIs, but the magnitude of their impact on human mortality remains unclear. To address this, we analyzed the microbial genomes, quantitative proteomes, and electronic medical records (EMRs) from 35,746 BSIs from Calgary, Canada (2006-2022). We show that EMR-based machine learning models accurately predict 30-day mortality (AUC=0.83), but surprisingly, integrating >70,000 microbial genes/proteins does not improve this performance. We demonstrate that microbial factors co-segregate with specific patient cohorts and are therefore not independent predictors of risk. We conclude that microbial virulence factors have minimal impact on mortality rates from BSIs.
Lee, J.; Cox, J. V.; Ouellette, S. P.
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Chlamydia trachomatis is an obligate intracellular, developmentally regulated pathogen with a reduced genome as a consequence of adapting to the host cell environment. Despite possessing only eight transcription factors, its developmental cycle is tightly regulated. Hence, we hypothesize that factors like post-transcriptional and post-translational modifications play significant roles in controlling developmental progression. Chlamydia encodes serine/threonine kinases, including an ortholog of Pkn1. In this study, we characterized the function of Pkn1 in chlamydial biology and revealed its role as a cell division regulator. We designed an anhydrotetracycline (aTc)-inducible construct encoding Pkn1 tagged with six histidines at the C-terminus (Pkn1_6xH). Wild-type Pkn1 localized primarily at the division septum whereas a kinase-null Pkn1 isoform localized in the cytosol. To further explore the association of Pkn1 with the divisome, we designed a plasmid encoding an aTc-inducible CRISPRi system targeting pkn1(pkn1KD). Intriguingly, decreased pkn1 transcript levels resulted in enlarged chlamydial cells with irregular coccoid shapes akin to penicillin-treated cells, indicating a block in cell division when pkn1 transcripts are reduced. These effects were complemented by expressing an additional wild-type copy, but not a kinase-null copy, of pkn1 during knockdown. Using a bacterial two hybrid system, we identified an interaction between Pkn1 and MreB, a cytoskeletal protein forming a ring at the septum in Chlamydia. We showed the co-localization of these proteins in Chlamydia and that inhibition of MreB function disrupts Pkn1 localization. Overall, our data indicate an essential function for Pkn1 activity in regulating cell division in Chlamydia.
Savas, L.; Pekok, A. U.; Pekok, B. S.; Eser, Z. S.
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Aim: Brucellosis remains endemic throughout the Mediterranean basin, the Middle East and Central Asia. Genitourinary involvement is an uncommon but clinically consequential focal complication that closely mimics urological emergencies and may precipitate unnecessary surgery. Contemporary data describing its frequency, laboratory signature and treatment outcomes in endemic settings remain limited. Material-Methods: We retrospectively screened all adults ([≥]18 years) with confirmed brucellosis managed at a tertiary infectious diseases unit between January 2008 and December 2020. Genitourinary involvement was defined as epididymo-orchitis, orchitis, epididymitis and/or brucellar pyelonephritis. Clinical, laboratory, ultrasonographic, therapeutic and outcome variables were abstracted using a standardised form. Proportions are reported with Wilson score 95% confidence intervals (CI). Reporting followed the STROBE statement. Result: Genitourinary involvement was identified in 18 of 125 patients with brucellosis (14.4%; 95% CI 9.3-21.6); 16 (88.9%) were men and the mean age was 35.2 years (range 22-62). Scrotal disease dominated the male presentation: epididymo-orchitis in 10 of 16 men (62.5%; 95% CI 38.6-81.5), orchitis in 4 (25.0%) and epididymitis in 2 (12.5%). Both women presented with pyelonephritis, one of whom developed a tubo-ovarian abscess requiring drainage. Constitutional features were near-universal (fatigue 100%, night sweats 88.9%, fever 77.8%). Leukocyte counts remained within the reference interval in every patient (mean 5,680/mm3), whereas erythrocyte sedimentation rate (mean 32 mm/h) and C-reactive protein (mean 24.2 mg/L) were only mildly to moderately raised. The Coombs anti-Brucella test was positive in 18 of 18 patients (100%) and the standard agglutination test in 17 of 18 (94.4%), whereas blood culture yielded Brucella melitensis in only 1 of 18 (5.6%). Concomitant extragenitourinary focal disease was present in 8 patients. All patients received doxycycline plus rifampicin; none required modification of the regimen or orchiectomy, and no treatment failure occurred (0 of 18; 95% CI 0-17.6). Median follow-up was 12 weeks (range 6-52) and no relapse was documented within this interval. Conclusions: In endemic regions, genitourinary brucellosis should be suspected in any patient with acute scrotal or flank symptoms accompanied by constitutional complaints, even when the leukocyte count is normal and acute-phase reactants are only marginally elevated. Coombs anti-Brucella serology rather than blood culture is the diagnostic cornerstone, and prompt doxycycline-rifampicin therapy averts surgical intervention.
Davis, A. J.; Hochberg, C. H.; Aziz, K. B.; Yan, L.; Sahetya, S.; Hager, D. N.; Iwashyna, T. J.
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Objective: To test the hypothesis that selected SIRS and SOFA criteria measured at ICU admission have divergent associations with (1) the development of new culture-confirmed infections and (2) early empiric broad-spectrum antibiotic receipt in critically ill patients with cirrhosis. Design: Retrospective, observational study using electronic health record (EHR) data. Setting: Both community and academic ICUs within a five-hospital health system between July 2017 and December 2025. Subjects: Adult patients >18 years of age diagnosed with cirrhosis admitted to the ICU within 96 hours of hospital admission. Patients transferred from outside facilities and those with positive cultures collected >24 hours before ICU admission were excluded. Interventions: None. Measurements: Multivariable logistic regression tested the association of the most aberrant values in nine SIRS/SOFA vital sign and laboratory parameters measured during the 24 hours prior to ICU admission with (1) the development a newly positive culture collected during the 24 hours before through the 96 hours after ICU admission and (2) receipt of broad-spectrum antibiotics during the 24 hours before through the 24 hours after ICU admission. Main Results: The presence of hyperthermia, hypothermia, hypoxia, or hypotension at ICU admission was associated with both culture positivity and antibiotic receipt. The presence of leukocytosis was associated with antibiotic receipt but not culture positivity. Among patients in the 21.6% of encounters with newly positive cultures, normothermia and normal WBC were common (respectively present in 97.2% and 77.5% of encounters) and associated with antibiotic omission at ICU admission despite the subsequent development culture positivity. Conclusions: Traditional physiologic markers of infection are often absent in critically ill patients with cirrhosis who develop new culture-confirmed infections at ICU admission, possibly contributing to delayed antibiotics. There may be opportunities to improve antibiotic delivery and stewardship at ICU admission in this high-risk population.
Paik, P.; tilak, R.; Tiwari, P.; Rai, A. k.; Gupta, M. K.; Varnika, S.
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Invasive candidiasis has become more common in recent decades, particularly within ICUs. Identifying specific Candida spp., and testing their sensitivity to antifungal drugs is crucial for effective treatment that helps healthcare providers to detect potential treatment challenges early. This study aimed to identify Candida spp. at their spp. level present in blood, assess their susceptibility to antifungal agents, and apply a random forest classifier to predict the best antifungal drug for a given species. The isolates were classified at the species complex level through MALDI-TOF MS. The strains' susceptibility to antifungal agents such as AMB, FLZ, VOZ, ITZ, POZ, CAS, MFN, and ANF was assessed using CLSI guidelines. Out of the 354 Candida spp. isolated from blood, C. utilis was found to be the predominant species, followed by C. tropicalis, and C. albicans. This study demonstrated that MFN and ANF exhibited high potency, with an impressive MIC90 of 0.12 {micro}g/mL against all isolates, surpassing CAS, which had a slightly higher overall MIC90 of 0.25 {micro}g/mL. FLZ exhibited the highest MIC90 value among the azoles at 16 {micro}g/mL, while VOZ, ITZ, and POZ all had MIC90 values of 0.5 {micro}g/mL. AMB MIC90 values were 2 {micro}g/mL against all isolated Candida species. The Random Forest AI/ML model showed perfect overall prediction, with the actual and predicted best antifungal drugs matching for all fungal species. This study is particularly essential because rare Candida spp. becoming more common and exhibiting higher MICs to AMB and FLZ and required suitable remedies for controlling the infection.
Hallström, E.; Kandavalli, V.; Marino Miguelez, M. H.; Elf, J.; Wählby, C.
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Antibiotic resistance is an increasingly serious problem worldwide. Identifying the bacterial species can help guide antibiotic selection and improve patient outcomes. In sepsis, where every minute counts, rapid identification is particularly important, and new approaches are needed. In this study, deep learning models were trained to identify bacterial species from phase-contrast time-lapse images of cells growing in microfluidic traps, without fluorescent labels. We demonstrated this approach in two previous studies using laboratory strains. Here, the previous work is extended to clinical bacterial isolates, evaluating performance on isolates not seen during training. Furthermore, it was tested whether autofluorescence could aid species identification. Two validation sets were acquired in separate experiments from the training data, the first containing clinical-isolate traps with five species (Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Staphylococcus aureus and Enterobacter cloacae), imaged every two minutes, and the second containing clinical isolates of two species (E. coli and K. pneumoniae) recovered from spiked donor blood, imaged every minute. Training with the best previous CNN method achieved unsatisfactory results. Therefore, vision transformers were explored, and a self-supervised adaptation procedure was developed for pretrained DINOv3 using a frozen teacher, followed by supervised classification using time-lapse montages. Mean macro-F1 was 93.6 {+/-} 1.3% for isolates precultured in Mueller-Hinton medium using 60 frames (118 minutes) and 87.2 {+/-} 2.7% for isolates precultured in blood using 55 frames (54 minutes) (mean {+/-} sample standard deviation across training seeds). Performance was evaluated over time by increasing the number of frames available to the model during testing, and Fourier-domain filtering approximated reduced numerical aperture. The results are promising and suggest that the aperture can be decreased while retaining good results. However, further evaluation on independent isolates, experiments and patient samples is needed to establish generalization. Together with previous findings, these results bring us closer to rapid image-based diagnostics that could transform the initial treatment of acute bacterial infections by enabling better-informed antibiotic selection.
Hulyalkar, N. V.; Salaudeen, I. O.; Gull, H.; Hau, I. N.; Sawant, N. V.; Zimmern, P. E.; Meloni, G.; De Nisco, N. J.
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Cytolysin is a toxin-bacteriocin commonly encoded by Enterococcus faecalis that can target erythrocytes, neutrophils, and macrophages as well as other Gram-positive bacteria. Cytolysin can lyse human, horse, rabbit, and mouse erythrocytes, but not sheep erythrocytes (SEs). It is hypothesized that SEs are resistant to cytolysin because they lack phosphatidylcholine (PC) in their membranes, while susceptible erythrocytes have PC-rich membranes, suggesting PC as a cytolysin binding target. Here, we isolated a urinary E. faecalis strain C33 that can efficiently lyse SEs and found that this activity was conserved among several E. faecalis clinical isolates. We demonstrated that although C33 cytolysin was necessary for SE lysis, it was not sufficient, suggesting a secondary factor enhances cytolysin activity against SEs. Through liposome assays we found that while PC was required for the activity of DS16 cytolysin, PC was dispensable for C33 cytolysin activity. To assess the biological significance of C33 cytolysin in the bladder microenvironment, we assessed C33 cytolysin activity against bladder epithelial cells and the urinary microbiota. We found that C33 cytolysin was more cytotoxic to human bladder epithelial cells than the canonical DS16 cytolysin. We also found greater inhibition of co-isolated urinary microbiota species Streptococcus parasanguinis, Enterococcus raffinosus, Staphylococcus capitis, and Corynebacterium coyleae by C33 cytolysin. Interestingly, E. faecalis C33 also inhibited the protective urogenital taxa Lactobacillus crispatus and Bifidobacterium longum. Together, these results reveal a new PC-independent cytolysin activity among clinical E. faecalis isolates that may support survival and competition in the urinary microenvironment.
Tejada-Arranz, A.; Sunder, V.; Basler, E.; Lanner, U.; Antelo-Varela, M.; Biehlmaier, O.; Fernando, R. C.; Jenal, U.; Schmidt, A.; Basler, M.
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P. aeruginosa is a Gram-negative, ubiquitous, opportunistic pathogen that can colonize open wounds and the respiratory airways and is particularly problematic for patients suffering from cystic fibrosis (CF) where it can cause chronic infections. One factor contributing to P. aeruginosa diversity during infection is phenotypic heterogeneity. Phenotypic heterogeneity is the ability of bacteria to express different levels of selected pathways, giving rise to multiple bacterial subpopulations in the same environment. The prevalence and relevance of this phenomenon have been poorly characterized in infection models. In this study, we developed strategies to detect these subpopulations via single cell reporters, flow cytometry and fluorescence microscopy, in simple infection models and a physiologically relevant, transwell-based model of the bronchial epithelium. Next, we optimized cell sorting coupled to low input proteomics approaches to characterize the physiological state of the identified subpopulations, and genetically manipulated P. aeruginosa to lock them in ON or OFF states of expression of phenotypically heterogeneous pathways. We identify that type IVc/Tad pili are expressed in a subset of P. aeruginosa cells and inflict damage to the host tissue, while type Tad pili-negative subpopulations express other virulence factors instead. Lastly, we validated the heterogeneous expression of this machinery across clinical strains. Our findings uncovered the diversity of strategies employed by P. aeruginosa for pathogenesis, where distinct bacterial subpopulations use different virulence factors to damage respiratory epithelia.
Zumba, M. A.; S., M.; A., J.; E., L.; H., M.; A., O.; F, R.; M., E.
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Sepsis is a global health problem. Patients in the Intensive Care Unit (ICU) are at risk of having sepsis because of their vulnerability and use of invasive medical devices. Emerging antimicrobial-resistance complicates treatment. Understanding bacterial profiles and antibiotic sensitivity patterns in the ICU plays an important role in managing sepsis, optimizing antimicrobial use, and improving patient outcomes. The aim of this study was to show bacterial profiles and antibiotic sensitivity patterns among patients who were admitted to the ICU at Mbeya Zonal Referral Hospital for 12 months. This was a prospective cross-sectional study among 187 sepsis-suspected patients. Data analysis was performed using SPSS Version 27. Categorical data were summarized by frequency and percentage. Fishers exact test, chi-square test, and modified Poisson regression were used to show the association between patients clinical variables and culture positivity at a 95% CI. Statistical significance was set at a p-value < 0.05. Out of 187 samples, 41.7% were culture positive. Gram-negative bacteria were commonly isolated (65.4%, with Klebsiella pneumoniae and Escherichia coli being commonly isolated. Commonly isolated Gram-positive bacteria were Coagulase-negative Staphylococcus species (19%). 100% of gram-positive bacteria and 96% of gram-negative bacteria were Multi-Drug Resistant (MDR), respectively. In multivariable analysis, patients who were intubated and mechanically ventilated (aPR = 2.208, 95% CI: 1.133-4.305, p = 0.020) and post-laparotomy patients (aPR = 3.241,95% CI: 1.320-7.958, p = 0.010) independently had a higher proportion of Gram-negative bacteria. The study reveals a high level of resistance to commonly used antimicrobials in our setting, necessitating strengthening of the antimicrobial stewardship program and routine surveillance of antimicrobial resistance patterns.
Phacharoen, S.; Prawang, A.; Kanchanasurakit, S.; Phonphok, K.; Duangrithi, D.; Petchcharee, P.; Sangsanit, W.; Jintasataporn, R.
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Background/Aims: In medical practice, the rising prevalence of infections in kidney transplant recipients (KTRs) is a notable concern. However, understanding the incidence and risk factors associated with infections in KTRs remains limited. This study aims to assess the incidence and factors associated infection among KTRs. Additionally, we also investigate the median time of each infection among KTRs. Methods: A retrospective cohort study was conducted from 1 January 2018- 31 December 2022 at Thailand's tertiary hospital. We performed univariable and multivariable logistic regression analyses to identify potential risk factors related infection and investigated for the incidence and median time of each infection among KTRs. Results: A total of 179 participants were included in this study. Our findings reveal the kidney from living donor was protective factor for infection among KTRs (aOR 0.063, 95% CI 0.005-0.792; p = 0.032). Urinary tract infections (UTIs)showed as the predominant pathogenic manifestation among KTRs (43%). The median time of UTIs, cytomegalovirus (CMV) infection and pneumocystis pneumonia (PCP) were 16, 57 and 94.5 days, respectively. Conclusions: Our study establishes that receiving a kidney from a living donor is a protective factor against post-kidney transplant infections. Particularly urinary tract infections were most common of infection. Monitoring urinary tract infections post-transplantation is recommended. Moreover, awareness of UTI, CMV infection and PCP should be concerned during 2-3 months after transplantation. However, due to a small sample size; we recommend to increase the number of particular participants in further investigations.
Khoo, J. J.; Beliavskaia, A. Y.; Ludwig, A.; Whitehead, M. A.; Al-Khafaji, A. M.; Hartley, C. S.; Kazimirova, M.; Bah, G. S.; Frederik, A.; Cahyani, I.; Loose, M. W.; Bell-Sakyi, L.; Darby, A. C.; Makepeace, B.
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Lateral gene transfer (LGT) from organellar to eukaryotic genomes is ubiquitous, resulting in the presence of widespread nuclear mitochondrial DNA segments (NUMTs) and/or plastid gene transfers. While LGT from bacterial associates of eukaryotes is generally less common, many arthropod genomes are littered with LGT originating from Wolbachia (order Rickettsiales) - a vertically transmitted, obligate intracellular symbiont of invertebrates. This contrasts with Rickettsia, a related genus including many important human pathogens, which has not been shown to promulgate LGT within its arthropod vectors. Here, we present the 8.6 Gb genome of a cell line derived from A. variegatum (the tropical bont tick), which is the primary vector of Rickettsia africae (agent of African tick-bite fever). In addition to numerous NUMTs and diverse families of transposable elements, an almost-complete chromosome of R. africae origin was identified in the cell line genome, localised to the putative sex chromosome. Sequencing of field-collected A. variegatum confirmed the presence of this large LGT in wild ticks, although the absence of transferred genes from the R. africae plasmid provided a means to differentiate LGT from genuine rickettsial infections. These findings highlight the imperative to consider the possibility of LGT when screening vectors for pathogens by PCR.
Boaitey, Y. A.; OWUSU-OFORI, A.; Bosshard, P. P.; AGHAKHANIAN, F.; Hennelly, C. M.; Raheem, S.; Arora, N.; Parr, J. B.; Gerbault, P.
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Skin ulcers, such as those observed in cases of the non-venereal disease yaws and the venereal disease syphilis, are traditionally diagnosed based on their anatomical location and visible appearance. Yet various evidence suggests that the pathogens that cause these ulcers may not be restricted to genital or non-genital body sites. We explored this by profiling the bacterial communities of genital and non-genital skin ulcers collected in Ghana using 16S rRNA gene amplicon sequencing. Swab samples were collected from 156 clinically diagnosed skin lesions (110 non-genital and 46 genital). The V1-V2 region of the 16S rRNA gene was sequenced to characterize bacterial communities. Microbial diversity, community composition, differential abundance, and associations between lesion diversity and common skin bacteria were analysed using bioinformatics and statistical methods. Following quality filtering, 135 samples were retained, revealing 23 bacterial phyla, 143 families, and 406 genera. Alpha diversity indicated similar bacterial richness and diversity in genital and non-genital skin lesions. Beta diversity analyses indicated differences between genital and non-genital lesions, accompanied by significant differences in within group dispersion. A log2 fold change analysis evidenced genital lesions were enriched in Gardnerella, whereas non-genital lesions showed more abundance of Staphylococcus, Streptococcus, Corynebacterium, Bradyrhizobium, and Pelomonas. Clinically important genera, including Treponema, Haemophilus, and Mycobacterium, were also detected, even in samples with low sequencing depths. Statistical modelling indicated that greater microbial diversity was associated with intermediate abundances of common skin taxa, particularly Corynebacteriaceae, Micrococcaceae, Cutibacterium, and Staphylococcaceae, thereby attesting the presence of polymicrobial communities in skin ulcers. Overall, genital and non-genital skin lesions showed similar microbial diversity but differed in composition. Our findings support the view of skin lesions as ecological niches containing diverse bacterial communities rather than being consistently dominated by a single bacterial taxon. They provide a basis for investigating possible polymicrobial interactions in skin ulcers.
Vidal, B.; Neves, S. O.; Santos, I. P.; Sardi, S. I.; Campos, G. s.
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Introduction: Acute gastroenteritis (AGE) is a global public health problem and a major cause of mortality in low- and lower-middle-income countries. Human bocavirus (HBoV) is among the viral agents associated with this condition. Therefore, investigating the presence of HBoV in cases of AGE in Salvador, Bahia, as well as its prevalence and circulating strains, is important. Objective: To investigate the occurrence of HBoV infection during an AGE outbreak in Salvador. Methods: A total of 178 samples were analyzed for HBoV using nested polymerase chain reaction (nested PCR), and the amplification products were visualized by agarose gel electrophoresis. HBoV was detected in 5.7% of the samples analyzed. Conclusion: This study contributes to the understanding of HBoV epidemiology as a secondary agent associated with acute gastroenteritis during a norovirus outbreak in Salvador. Continued investigation and identification of the etiological agents involved in outbreaks are essential for evaluating the causes of AGE. These findings also highlight the need for broader diagnostic approaches and the importance of phylogenetic analysis for monitoring and controlling viral infections.