The obligate intracellular bacterium Chlamydia trachomatis is the most common bacterial STD agent in the US. This bacterium has a unique biphasic developmental cycle in which the infectious elementary body (EB) infects a host mucosal epithelial cell and differentiates into the replicative form (the reticulate body or RB) within a modified vacuole called an inclusion. The RB later divides and develops back into an EB and is released, perpetuating the infectious cycle. When developing chlamydiae are exposed to unfavorable environmental conditions, they deviate from the normal developmental cycle into a non-infectious but viable state termed persistence. Previous data from our laboratory indicate that i) during C. trachomatis/HSV co-infection, the chlamydiae become persistent and ii) HSV gD interaction with host cell surface is sufficient to induce this response. During viral entry, HSV gD interacts with one of four host co-receptors, one of which is the host adhesion molecule nectin-1. Interestingly, Western blotting demonstrated that nectin-1 is significantly decreased in C. trachomatis-infected HeLa cells. Additional studies indicated that active C. trachomatis replication is required for nectin-1 down-regulation and nectin-1 is likely down-regulated post-translationally. CPAF, a chlamydia-secreted protease, is responsible for degrading several host proteins. Both in vivo experiments using CPAF-specific chemical inhibitors and cell-free cleavage assays using recombinant CPAF indicate that nectin-1 is degraded by CPAF in C. trachomatis-infected cells. Further studies suggest that nectin-1 is the most likely candidate involved in triggering HSV-induced chlamydial persistence. Co-infection experiments using nectin-1-specific HSV-1 mutants suggest that nectin-1 is, indeed, required for persistence induction. Additional studies in single co-receptor-expressing CHO cells demonstrate that, despite the fact that HSV-1 enters both HVEM- and nectin-1-expressing cells, viral co-infection reduces chlamydial infectivity only in the CHO-nectin-1 cell line. These data confirm that HSV/nectin-1 interaction is sufficient for chlamydial persistence induction. Although nectin-1 ligation is known to activate Cdc42, pull-down assays indicate that Cdc42 is not activated in co-infected HeLa cells. Taken together, these data suggest that: i) HSV gD-nectin-1 binding activates a novel host epithelial cell pathway that restricts chlamydial development and ii) the chlamydiae may degrade nectin-1 to evade this inhibitory host response.

Bacterial sexually transmitted infections (STIs), notably syphilis, gonorrhea, and chlamydia, have been increasing among men who have sex with men (MSM) in the United States. The rise has been attributed to various factors, including increased condomless sexual acts due to the high uptake of pre-exposure prophylaxis (PrEP) for HIV prevention. To address this concerning trend, post-exposure prophylaxis with doxycycline (Doxy-PEP) has emerged as a potential biomedical intervention. This study aimed to assess the effectiveness of Doxy-PEP in preventing bacterial STIs among MSM in Central Florida, a region with rising STI rates. A de-identified dataset from Pineapple Health Clinic in Orlando, Florida, was analyzed (n = 73) participants who received Doxy-PEP for bacterial STIs between July 01, 2022, and June 30, 2023. Results revealed elevated rates of any bacterial STI and syphilis incidence among both HIV-negative and HIV-positive individuals, contrary to expectations from previous literature. Notably, the HIV-positive cohort showed significantly higher incidence rates of syphilis. The study also found discrepancies in gonorrhea incidence and resistance profiles, raising questions about the effectiveness of Doxy-PEP against gonorrhea in this population. The older age of the HIV-positive cohort and differences in medication regimens further complicated the analysis. These findings suggest the effectiveness of Doxy-PEP may vary in real-world settings compared to controlled trials. Limitations include the small sample size, single healthcare clinic setting, differences in medication regimens, and the investigational status of Doxy-PEP. However, the study highlights the need for interventions considering diverse demographics and local antibiotic resistance patterns. Future research should explore these factors to develop effective strategies for reducing STI incidence among MSM in Central Florida.

Clostrioides difficile is a common cause of nosocomial (hospital-acquired) infections. Patients receiving antibiotic treatment experience dysbiosis of gut microbiota, and C. difficile, normally held in check by the various other organisms, takes this opportunity to propagate. Symptoms of infection generally include diarrhea, colitis, dehydration, and fever. Understanding that C. difficile generally only causes illness when it is the dominant bacterium (i.e. when growth is relatively unchecked by other microbes), it is appropriate to investigate potential competitive organisms that may be introduced after antibiotic courses or during active C. difficile infection to effectively displace it. Fecal samples from the University of Central Florida Lift fecal collection station were aseptically plated onto modified cycloserine cefoxitin fructose agar (CCFA). Visually remarkable colonies (certain colonies that looked unique in comparison to others) were restreaked on new plates of the same media to verify growth, then transferred to brain heart infusion-supplemented (BHIS) plates for propagation. Colonies were inoculated in glycerol stocks for storage, then grown in BHIS liquid media to prepare for identification. Genomic extraction was performed on each sample, and spectrophotometric quantification and gel electrophoresis were executed to confirm successful extraction. Genomic samples will be sent to an external laboratory for identification via polymerase chain reaction and Sanger sequencing. We hypothesize that at least one bacterial strain from the fecal collection station will potentially inhibit C. difficile infection. Should such an organism be identified, it follows that the efficacy of its application in conventional hospital settings may be examined. Current regulation of fecal microbiota transplants, an effective therapeutic practice, is cumbersome, and changing the classification of fecal transplants may improve timeliness and effectiveness of treatment.

Cryptococcus neoformans is an encapsulated yeast responsible for severe meningoencephalitis. The importance of epidemiological studies on cryptococcosis has increased since the beginning of the AIDS epidemic. C. neoformans exists in two varieties containing four serotypes, C. neoformans var. neoformans (serotypes A and D) and C. neoformans var. gattii (serotypes B and C). Locally C. neoformans var. neoformans has been associated with pigeon feces during those months having an average temperature of 64.2°F j(17.8°C) and above. Clinical and environmental isolates of C. neoformans obtained from regional hospitals and environmental samplings, respectively, have been grouped into their variety status utilizing canavanine-glycine-bromthymol blue agar. Polyclonal antisera against C. neoformans serotypes A, B, C and D were isolated from challenged rabbits. Serotyping C. neofromans isolates using the polyclonal antisera resulted in 57% (20 of 35) of the serotypes confirmed with a direct immunofluorescent assay utilizing a single monoclonal antibody (E1). Data from the immunofluorescence assay suggest all C. neoformans obtained from regional hospitals (26 of 26) and those isolated from the environment (9 of 9) belong to the A serotype group. These data have provided information leading to the origin of infection for cryptococcosis in our region, which may be beneficial to immunocompromised individuals.

M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Science), Vaal University of Technology| / Pigeon droppings, found in abundance in most cities and towns where pigeons are found, are a source of potential yeast and molds into the environment. Invasive fungal infections are a cause of morbidity and often mortality in immunocompromised individuals. The objective of this study was to the identification of bacterial and mold agents from pigeon droppings. Pigeon droppings samples were collected from three locations during the winter and summer months and studied for the occurrence of bacteria, yeast and molds by utilising culture-independent techniques. Amplification of the 16S rDNA gene and the internal transcribed spacer (ITS) region, cloning and ARDRA and DGGE were used for the characterisation of the microbial populations followed by sequencing. Several mold and yeasts, as well as bacteria were found to be present in pigeon droppings, which can spread into the environment and be transmitted to immunocompromised individuals and children. DGGE analysis of the bacterial communities revealed banding patterns that clustered all but one winter samples and all summer samples, showing a high similarity among the microbial members in both seasons and sample locations. Fungal DGGE analysis revealed clusters that grouped summer and winter samples from Johannesburg and Pretoria while VUT samples were clustered on their own. From the identification of fungal and bacterial DNA, Cryptococcus species was the majority of fungi isolated from the dropping samples. Geotrichum, Kazachstania and Fusarium species were isolated from phylotypes obtained from ITS amplicons analysed by ARDRA. Lactobacillus and Enteroccoccus species, organisms usually found in the gastrointestinal tract were the common bacterial members identified. The results showed no difference in microbial communities across all sample locations, while seasonal changes also had no impact in microbial community patterns.

Scrub typhus is a potentially fatal infection that threatens one billion persons in the Asia-Pacific region and is caused by the obligate intracellular bacterium, Orientia tsutsugamushi. How this organism facilitates its intracellular survival and pathogenesis is poorly understood. Intracellular bacterial pathogens utilize the Type 1 (T1SS) or Type 4 secretion system (T4SS) to translocate ankyrin repeat-containing proteins (Anks) into the host cell to modulate host cell processes. The O. tsutsugamushi genome encodes one of the largest known bacterial Ank libraries as well as Type 1 and Type 4 secretion systems (T1SS and T4SS), which are expressed during infection. In silico analyses of the Anks’ C-termini revealed that they possess characteristics of T1SS secretion signals. Escherichia coli expressing a functional T1SS was able to secrete chimeric hemolysin proteins bearing the C-termini of 19 of 20 O. tsutsugamushi Anks. In addition to infecting endothelial cells, O. tsutsugamushi infects professional phagocytes. To better understand why these innate immune cells are unable to eliminate O. tsutsugamushi, we addressed the activity of host NF-κB proinflammatory transcription factor. Screening of O. tsutsugamushi infected cells at an MOI of 1 revealed inhibition of NF-κB nuclear accumulation as early as 8 hours in HeLa and bone-marrow derived macrophage cells. When stimulating infected cells with TNF-α, IκBα degradation still occurs, however NF-κB dependent gene transcription remains downregulated. Immunofluorescence microscopic analysis of TNF-α treated cells ectopically expressing all O. tsutsugamushi Anks revealed that two nuclear trafficking Anks, Ank1 and Ank6, result in a significant decrease in NF-κB nuclear accumulation. Additionally, these Anks also significantly inhibited NF-κB dependent gene transcription. Co-immunoprecipitation experiments revealed that both Anks interact with importin-β1, exportin-1, and the p65 NF-κB subunit. Treating cells with importazole significantly reduces the nuclear accumulation of Ank1 and Ank6. Finally, treating infected cells or cells ectopically expressing Ank1 or Ank6 with leptomycin B resulted in restoration of NF-κB nuclear accumulation. With these data, we propose that O. tsutsugamushi secretes Ank1 and Ank6 to initially interact with importin-β1, which permits their nuclear entry where they then interact with NF-κB and subsequently exportin-1 to prevent NF-κB nuclear accumulation.

A newly discovered cysteine protease, Prp, has been shown to perform an essential, site-specific cleavage of ribosomal protein L27 in Staphylococcus aureus. In Firmicutes and related bacteria, ribosomal protein L27 is encoded with a conserved N-terminal extension that must be removed to expose residues critical for ribosome function. Uncleavable and pre-cleaved variants were unable to complement an L27 deletion in S. aureus, indicating that this N-terminal processing event is essential and likely plays an important regulatory role. The gene encoding the responsible protease (prp) has been shown to be essential, and is found in all organisms encoding the N-terminal extension of L27. Cleavage of L27 by Prp represents a new target for potential antibiotic therapy. In order to characterize this protease, Prp has been overexpressed and purified. Using an assay we have developed, based on cleavage of a fluorogenic peptide derived from the conserved L27 cleavage sequence, we have undertaken an analysis of the enzyme kinetics and substrate specificity for Prp cleavage and tested predictions made based on a structural model using active-site mutants.

Introdução: Em estudo prospectivo, os efeitos da gastroplastia redutora com reconstrução em Y de Roux sobre a flora bacteriana e produção de citoquinas nas câmaras gástricas proximal e excluída foram estudados. Métodos: pacientes bariátricos (n=37) foram submetidos à avaliação endoscópica em ambos reservatórios gástricos,7,3+-1,4 anos após a gastroplastia. Idade foi de 42,4+-9,9 anos (70,2% sexo feminino), IMC pré-operatório de 53,5+-10,6, e IMC atual de 32,6+-7,8kg/m2. TNFalfa e TGF-beta foram medidos pelo método ELISA em biópsias da mucosa gástrica., assim como cultura quantitativa da secreção gástrica, com pH gástrico e teste respiratório lactulose/hidrogênio.Resultados: Nenhum dos pacientes apresentou queixas sugestivas de supercrescimento bacteriano gastrointestinal. Todavia, contagens elevadas de bactérias e fungos foram identificadas nas duas câmaras, principalmente no estômago proximal. Gram-positivos representaram a maioria dos isolados. O pH foi neutro na câmara proximal, enquanto que também na câmara distal nem sempre conservou-se em níveis esperados. Conclusões: 1)Produção elevadas de TNF-alfa e TGF-beta, com a colonização de aeróbios, anaeróbios e fungos em ambas câmaras gástricas foram identificadas; 2)O pH gástrico como a contagem bacteriana foram maiores no estômago proximal funcionante; 3)Teste respiratório foi positivo para supercrescimento bacteriano em 40,5% dos pacientes,entretanto não foram identificadas manifestações clínicas de supercrescimento bacteriano gastrointestinal. / Background: In a prospective study, the effect of Roux-en-Y gastric bypass (RYGBP) on bacterial flora and cytokines production in the used (proximal pouch) and unused (large bypassed) gastric chamber was analysed. Methods: Bariatric subjects (n=37) were submitted to endoscopic examination of both gastric reservoirs, 7.3 ± 1.4 years after RYGBP. Age was 42.4 ± 9.9 years (70.2% females), preoperative BMI was 53.5 ± 10.6, and current BMI was 32.6 ± 7.8 kg/m2.TNF-alpha and TGF-beta were meausured by enzyme-linked immunosorbent assay (ELISA) from gastric mucosal biopsies. Quantitative culture of gastric secretion along with gastric pH and actulose/hydrogen breath test were also investigated.Results: None of the subjects displayed complaints suggestive of GI bacterial overgrowth. Elevated counts of bacteria and fungi were identified in both chambers, mostly in the proximal stomach. Gram-positives represented the majority of the isolates. Gastric pH was neutral in the proximal pouch, whereas the distal chamber mostly but not always onserved the expected acidity. Conclusions: 1)Increased TNF-alpha and TGFbeta production, as aerobes, anaerobes and fungi colonization of both gastric chambers was detected; 2) Gastric pH as well as bacterial count was higher in the functioning proximal stomach; 3) Breath test was positive for bacterial overgrowth in 40.5% of the subjects, however clinical manifestation of GI bacterial overgrowth were not demonstrated

Introdução: Em estudo prospectivo, os efeitos da gastroplastia redutora com reconstrução em Y de Roux sobre a flora bacteriana e produção de citoquinas nas câmaras gástricas proximal e excluída foram estudados. Métodos: pacientes bariátricos (n=37) foram submetidos à avaliação endoscópica em ambos reservatórios gástricos,7,3+-1,4 anos após a gastroplastia. Idade foi de 42,4+-9,9 anos (70,2% sexo feminino), IMC pré-operatório de 53,5+-10,6, e IMC atual de 32,6+-7,8kg/m2. TNFalfa e TGF-beta foram medidos pelo método ELISA em biópsias da mucosa gástrica., assim como cultura quantitativa da secreção gástrica, com pH gástrico e teste respiratório lactulose/hidrogênio.Resultados: Nenhum dos pacientes apresentou queixas sugestivas de supercrescimento bacteriano gastrointestinal. Todavia, contagens elevadas de bactérias e fungos foram identificadas nas duas câmaras, principalmente no estômago proximal. Gram-positivos representaram a maioria dos isolados. O pH foi neutro na câmara proximal, enquanto que também na câmara distal nem sempre conservou-se em níveis esperados. Conclusões: 1)Produção elevadas de TNF-alfa e TGF-beta, com a colonização de aeróbios, anaeróbios e fungos em ambas câmaras gástricas foram identificadas; 2)O pH gástrico como a contagem bacteriana foram maiores no estômago proximal funcionante; 3)Teste respiratório foi positivo para supercrescimento bacteriano em 40,5% dos pacientes,entretanto não foram identificadas manifestações clínicas de supercrescimento bacteriano gastrointestinal. / Background: In a prospective study, the effect of Roux-en-Y gastric bypass (RYGBP) on bacterial flora and cytokines production in the used (proximal pouch) and unused (large bypassed) gastric chamber was analysed. Methods: Bariatric subjects (n=37) were submitted to endoscopic examination of both gastric reservoirs, 7.3 ± 1.4 years after RYGBP. Age was 42.4 ± 9.9 years (70.2% females), preoperative BMI was 53.5 ± 10.6, and current BMI was 32.6 ± 7.8 kg/m2.TNF-alpha and TGF-beta were meausured by enzyme-linked immunosorbent assay (ELISA) from gastric mucosal biopsies. Quantitative culture of gastric secretion along with gastric pH and actulose/hydrogen breath test were also investigated.Results: None of the subjects displayed complaints suggestive of GI bacterial overgrowth. Elevated counts of bacteria and fungi were identified in both chambers, mostly in the proximal stomach. Gram-positives represented the majority of the isolates. Gastric pH was neutral in the proximal pouch, whereas the distal chamber mostly but not always onserved the expected acidity. Conclusions: 1)Increased TNF-alpha and TGFbeta production, as aerobes, anaerobes and fungi colonization of both gastric chambers was detected; 2) Gastric pH as well as bacterial count was higher in the functioning proximal stomach; 3) Breath test was positive for bacterial overgrowth in 40.5% of the subjects, however clinical manifestation of GI bacterial overgrowth were not demonstrated

O principal mecanismo de defesa de hospedeiros infectados pelo Paracoccidioides brasiliensis (Pb), fungo dimórfico que causa a mais importante micose sistêmica da América Latina, é a imunidade celular. Neste processo participam macrófagos ativados por IFN-<font face=\"Symbol\">g e a IL-10 parece ser a citocina que se contrapõe a esta ativação. Tanto na patologia humana como em modelos experimentais há fortes indicações de que a IL-10 age como supressora da imunidade celular causando efeitos deletérios aos hospedeiros; entretanto, estudos diretos sobre a função da IL-10 na paracoccidiodomicose (PCM) não tinham sido ainda realizados. Então o objetivo fundamental deste trabalho foi estudar a função da IL-10 nos mecanismos da imunidade inata e adaptativa contra o Pb utilizando como modelo experimental camundongos geneticamente deficientes de IL-10 (IL-10 nocaute, IL-10 KO) em comparação com seus controles normais (WT). Demonstramos in vitro que macrófagos peritoneais normais de camundongos IL-10 KO apresentam uma maior atividade fagocítica e fungicida que os macrófagos de camundongos WT e isto esteve associado à maior produção de IFN-<font face=\"Symbol\">g, TNF-<font face=\"Symbol\">&#945, óxido nítrico (NO) e da quimiocina MCP-1. Verificamos, entretanto, que a produção de IFN-<font face=\"Symbol\">g era realizada por células NKT contaminantes de macrófagos aderentes nos camundongos IL-10 KO, sugerindo uma possível participação destas células na ativação de macrófagos e de células T de camundongos IL-10 KO. Estudos in vivo revelaram que a partir da 2ª semana de infecção os camundongos IL-10 KO apresentaram uma resposta imune precoce em relação aos WT, pois os pulmões dos primeiros apresentavam carga fúngica significativamente menor, associada com aumento da maioria dos isótipos de anticorpos (IgM, IgG1, IgG2a, IgG2b) específicos contra o fungo. Observamos também a inibição total da produção das citocinas IL-4 e IL-5, mostrando a ação reguladora da IL-10 na síntese de citocinas Th2. Na 4ª semana pós-infecção a carga fúngica continuou menor nos animais IL-10 KO, mas não foram observadas as diferenças quanto à síntese de anticorpos entre as duas linhagens. A análise dos leucócitos infiltrantes nos pulmões revelou um aumento na frequência de linfócitos T CD4+ ativados nos camundongos IL-10 KO em relação aos WT. A partir da 8ª semana, a carga fúngica pulmonar dos camundongos IL-10 KO reduziu consideravelmente e não ocorreu disseminação para outros órgãos. Observou-se também, nesta linhagem, um aumento na resposta de hipersensibilidade do tipo tardio (HTT), confirmando o padrão de resposta desviado para um perfil Th1. A análise histológica dos órgãos dos camundongos IL-10 KO revelou ausência de granulomas e fungos no pulmão em contraste aos seus controles WT que apresentavam elevado número de granulomas e fungos neste órgão. A análise dos linfócitos infiltrantes nos pulmões dos camundongos IL-10 KO mostrou redução na frequência de células B, o que é coerente com a baixa síntese de anticorpos observada. Houve aumento marcante na freqüência de células T CD4+ e T CD8+ memória/efetora, caracterizando mais uma vez a eficiente resposta imune celular nesses animais associada à ausência do papel regulador negativo da IL-10. Em fase mais tardia (16 semanas pós-infecção) a regressão da infecção nos camundongos IL-10 KO continuou evidente pelo pequeno número de fungos recuperados do pulmão, acompanhada de baixa síntese de citocinas (IL-5 e IL-2) e de anticorpos anti- P. brasiliensis. Na 23ª semana de infecção além da baixa carga fúngica nos camundongos IL-10 KO, associada à baixa frequência de células responsáveis pela imunidade celular ocorreu também redução na freqüência de células Treg, indicando o papel regulador da IL-10 nesta subpopulação celular. A elevada sobrevida (90%) dos animais IL-10 KO foi coerente com a baixa carga fúngica e eficiente resposta imune no curso da infecção. Em conjunto, nosso trabalho demonstra o importante papel regulador da IL-10 na imunidade da PCM. / Cellular immunity is the main defense mechanism of hosts infected by the Paracoccidioide brasiliensis (Pb), a dimorphic fungus that causes the most important systemic mycosis in Latin America. IFN-<font face=\"Symbol\">g activated macrophages participate in this activity that is antagonized by IL-10 an anti-inflammatory cytokine. Both, in the human pathology and in experimental models, there are a number of evidences indicating that IL-10 acts as a suppressor of cellular immunity leading to deleterious effects to the hosts. However, direct studies aimed at investigating the function of IL-10 in the immunity to paracoccidioidomycosis (PCM) have not been performed. Thus, the fundamental objective of this work was to study the function of IL-10 in the mechanisms of innate and adaptive immunity against Pb using as experimental model IL-10 deficient mice (IL-10 Knockout, IL-10 KO) compared to their respective wild type (WT) controls. We demonstrated in vitro that normal peritoneal macrophages of IL-10 KO mice presented increased phagocytic and microbicidal activities than macrophages of WT mice and this was associated witch an elevated production of IFN-<font face=\"Symbol\">g, TNF-<font face=\"Symbol\">&#945, nitric oxide (NO) and the chemokine MCP-1. However, the production of IFN-<font face=\"Symbol\">g seen to be performed by NTK cells contaminating adherent macrophages, suggesting a possible participation of these cells in the activation of macrophages and T cells of IL-10 KO mice. In vivo studies revealed that at the second week of infection IL-10 KO mice presented an earlier immune response when compared to wild-type mice, since their lungs exhibited a significantly reduced fungal burden and an increased production of almost all antibodies isotypes (IgM, IgG1, IgGM, IgG2b). This effect was accompanied by a total absence of IL-4 and IL-5, showing a regulatory action of IL-10 in the synthesis of Th2 cytokines. Four weeks post-infection, the fungal load was still lower in the IL-10 KO mice but no differences in antibody synthesis was observed. However, the analysis of lung infiltrating leukocytes revealed an increased frequency of TCD4+ and TCD4+CD44 high lymphocytes in IL-10 KO mice, again demonstrating an early activation of cellular immunity in IL-10 KO mice. When compared with WT mice, the pulmonary fungal loads of IL-10 KO mice at week 8 of infection were drastically reduced and no dissemination to other organs were observed. The histopathological analysis revealed an absence of granulomas and fungi in the lungs of IL-10 KO in comparison with WT mice. The analysis of lung infiltrating leukocytes showed that IL-10 KO mice had a reduction in the frequency of B cells, in agreement with the reduced synthesis of immunoglobulins. An increased frequency of activated T CD4+ and a drastic increase of TCD4+ and T CD8+ effector/memory cells charactering once again an efficient immune response associated with IL-10 deficiency. In later stages, sixteen weeks after infection, a regressive infection of IL-10 KO mice was further characterized by low numbers of fungi in the lung, reduced synthesis of cytokines (IL-4 and IL-5) and anti- P. brasiliensis antibodies. By week 23 after infection, in addition to the characteristic reduction of fungal loads and reduced frequency of immune cells, we observed a decrease in the frequency of Treg cells, demonstrating the implication of IL-10 in the control of this T cell population. The elevated survival (90%) of IL-10 KO mice was in total agreement with the low fungal burdens and efficient immune response observed during infection. In conclusion, our work demonstrates for the first time that IL-10 plays a major role in the control of innate and adaptive immunity to Pb infection.