scholarly journals Persistent Mycoplasma genitalium Infection of Human Endocervical Epithelial Cells Elicits Chronic Inflammatory Cytokine Secretion

2012 ◽  
Vol 80 (11) ◽  
pp. 3842-3849 ◽  
Author(s):  
Chris L. McGowin ◽  
Rochelle S. Annan ◽  
Alison J. Quayle ◽  
Sheila J. Greene ◽  
Liang Ma ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Cytokine ◽  
Mycoplasma Genitalium ◽  
Clinical Findings ◽  
Cytokine Secretion ◽  
Host Cells ◽  
Content Type ◽  
Sexually Transmitted ◽  
Host Immune Responses ◽  
Tract Infections

ABSTRACTInfection withMycoplasma genitaliumhas been associated with male and female urogenital disease syndromes, including urethritis, cervicitis, pelvic inflammatory disease (PID), and tubal factor infertility. Basic investigations of mucosal cytotoxicity, microbial persistence, and host immune responses are imperative to understanding these inflammatory urogenital syndromes, particularly in females, considering the potential severity of upper tract infections. Here, we report thatM. genitaliumcan establish long-term infection of human endocervical epithelial cells that results in chronic inflammatory cytokine secretion and increased responsiveness to secondary Toll-like receptor (TLR) stimulation. Using a novel quantitative PCR assay,M. genitaliumwas shown to replicate from 0 to 80 days postinoculation (p.i.), during which at most time points the median ratio ofM. genitaliumorganisms to host cells was ≤10, indicating that low organism burdens are capable of eliciting chronic inflammation in endocervical epithelial cells. This observation is consistent with clinical findings in women. Persistently secreted cytokines predominately consisted of potent chemotactic and/or activating factors for phagocytes, including interleukin-8 (IL-8), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1β (MIP-1β). Despite persistent cytokine elaboration, no host cell cytotoxicity was observed except with superphysiologic loads ofM. genitalium, suggesting that persistent infection occurs with minimal direct damage to the epithelium. However, it is hypothesized that chronic chemokine secretion with leukocyte trafficking to the epithelium could lead to significant inflammatory sequelae. Therefore, persistentM. genitaliuminfection could have important consequences for acquisition and/or pathogenesis of other sexually transmitted infections (STIs) and perhaps explain the positive associations between this organism and human immunodeficiency virus (HIV) shedding.

scholarly journals Fur Represses Adhesion to, Invasion of, and Intracellular Bacterial Community Formation within Bladder Epithelial Cells and Motility in Uropathogenic Escherichia coli

2016 ◽  
Vol 84 (11) ◽  
pp. 3220-3231 ◽  
Author(s):  
Kumiko Kurabayashi ◽  
Tomohiro Agata ◽  
Hirofumi Asano ◽  
Haruyoshi Tomita ◽  
Hidetada Hirakawa
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Antimicrobial Agents ◽  
Host Cells ◽  
Type I ◽  
Wild Type ◽  
Content Type ◽  
Type I Fimbriae ◽  
Tract Infections

Uropathogenic Escherichia coli (UPEC) is a major pathogen that causes urinary tract infections (UTIs). This bacterium adheres to and invades the host cells in the bladder, where it forms biofilm-like polymicrobial structures termed intracellular bacterial communities (IBCs) that protect UPEC from antimicrobial agents and the host immune systems. Using genetic screening, we found that deletion of the fur gene, which encodes an iron-binding transcriptional repressor for iron uptake systems, elevated the expression of type I fimbriae and motility when UPEC was grown under iron-rich conditions, and it led to an increased number of UPEC cells adhering to and internalized in bladder epithelial cells. Consequently, the IBC colonies that the fur mutant formed in host cells were denser and larger than those formed by the wild-type parent strain. Fur is inactivated under iron-restricted conditions. When iron was depleted from the bacterial cultures, wild-type UPEC adhesion, invasion, and motility increased, similar to the case with the fur mutant. The purified Fur protein bound to regions upstream of fimA and flhD , which encode type I fimbriae and an activator of flagellar expression that contributes to motility, respectively. These results suggest that Fur is a repressor of fimA and flhD and that its repression is abolished under iron-depleted conditions. Based on our in vitro experiments, we conclude that UPEC adhesion, invasion, IBC formation, and motility are suppressed by Fur under iron-rich conditions but derepressed under iron-restricted conditions, such as in patients with UTIs.

scholarly journals Immunomodulatory Effects of Pneumococcal Extracellular Vesicles on Cellular and Humoral Host Defenses

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Mario Codemo ◽  
Sandra Muschiol ◽  
Federico Iovino ◽  
Priyanka Nannapaneni ◽  
Laura Plant ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Plasma Membrane ◽  
Streptococcus Pneumoniae ◽  
Extracellular Vesicles ◽  
Factor H ◽  
Host Cells ◽  
Immunomodulatory Effects ◽  
Content Type ◽  
Associated Proteins ◽  
Tract Infections

ABSTRACTGram-positive bacteria, including the major respiratory pathogenStreptococcus pneumoniae, were recently shown to produce extracellular vesicles (EVs) that likely originate from the plasma membrane and are released into the extracellular environment. EVs may function as cargo for many bacterial proteins, however, their involvement in cellular processes and their interactions with the innate immune system are poorly understood. Here, EVs from pneumococci were characterized and their immunomodulatory effects investigated. Pneumococcal EVs were protruding from the bacterial surface and released into the medium as 25 to 250 nm lipid stained vesicles containing a large number of cytosolic, membrane, and surface-associated proteins. The cytosolic pore-forming toxin pneumolysin was significantly enriched in EVs compared to a total bacterial lysate but was not required for EV formation. Pneumococcal EVs were internalized into A549 lung epithelial cells and human monocyte-derived dendritic cells and induced proinflammatory cytokine responses irrespective of pneumolysin content. EVs from encapsulated pneumococci were recognized by serum proteins, resulting in C3b deposition and formation of C5b-9 membrane attack complexes as well as factor H recruitment, depending on the presence of the choline binding protein PspC. Addition of EVs to human serum decreased opsonophagocytic killing of encapsulated pneumococci. Our data suggest that EVs may act in an immunomodulatory manner by allowing delivery of vesicle-associated proteins and other macromolecules into host cells. In addition, EVs expose targets for complement factors in serum, promoting pneumococcal evasion of humoral host defense.IMPORTANCEStreptococcus pneumoniaeis a major contributor to morbidity and mortality worldwide, being the major cause of milder respiratory tract infections such as otitis and sinusitis and of severe infections such as community-acquired pneumonia, with or without septicemia, and meningitis. More knowledge is needed on how pneumococci interact with the host, deliver virulence factors, and activate immune defenses. Here we show that pneumococci form extracellular vesicles that emanate from the plasma membrane and contain virulence properties, including enrichment of pneumolysin. We found that pneumococcal vesicles can be internalized into epithelial and dendritic cells and bind complement proteins, thereby promoting pneumococcal evasion of complement-mediated opsonophagocytosis. They also induce pneumolysin-independent proinflammatory responses. We suggest that these vesicles can function as a mechanism for delivery of pneumococcal proteins and other immunomodulatory components into host cells and help pneumococci to avoid complement deposition and phagocytosis-mediated killing, thereby possibly contributing to the symptoms found in pneumococcal infections.

scholarly journals Initial Characterization of the Two ClpP Paralogs ofChlamydia trachomatisSuggests Unique Functionality for Each

2018 ◽  
Vol 201 (2) ◽  
Author(s):  
Nicholas A. Wood ◽  
Krystal Y. Chung ◽  
Amanda M. Blocker ◽  
Nathalia Rodrigues de Almeida ◽  
Martin Conda-Sheridan ◽  
...  
Keyword(s):  
Host Cells ◽  
Developmental Cycle ◽  
Intracellular Bacteria ◽  
Clp Protease ◽  
Content Type ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Developmental Form ◽  
Obligate Intracellular Bacteria

ABSTRACTMembers ofChlamydiaare obligate intracellular bacteria that differentiate between two distinct functional and morphological forms during their developmental cycle, elementary bodies (EBs) and reticulate bodies (RBs). EBs are nondividing small electron-dense forms that infect host cells. RBs are larger noninfectious replicative forms that develop within a membrane-bound vesicle, termed an inclusion. Given the unique properties of each developmental form of this bacterium, we hypothesized that the Clp protease system plays an integral role in proteomic turnover by degrading specific proteins from one developmental form or the other.Chlamydiaspp. have five uncharacterizedclpgenes,clpX,clpC, twoclpPparalogs, andclpB. In other bacteria, ClpC and ClpX are ATPases that unfold and feed proteins into the ClpP protease to be degraded, and ClpB is a deaggregase. Here, we focused on characterizing the ClpP paralogs. Transcriptional analyses and immunoblotting determined that these genes are expressed midcycle. Bioinformatic analyses of these proteins identified key residues important for activity. Overexpression of inactiveclpPmutants inChlamydiaspp. suggested independent function of each ClpP paralog. To further probe these differences, we determined interactions between the ClpP proteins using bacterial two-hybrid assays and native gel analysis of recombinant proteins. Homotypic interactions of the ClpP proteins, but not heterotypic interactions between the ClpP paralogs, were detected. Interestingly, protease activity of ClpP2, but not ClpP1, was detectedin vitro. This activity was stimulated by antibiotics known to activate ClpP, which also blocked chlamydial growth. Our data suggest the chlamydial ClpP paralogs likely serve distinct and critical roles in this important pathogen.IMPORTANCEChlamydia trachomatisis the leading cause of preventable infectious blindness and of bacterial sexually transmitted infections worldwide. Chlamydiae are developmentally regulated obligate intracellular pathogens that alternate between two functional and morphologic forms, with distinct repertoires of proteins. We hypothesize that protein degradation is a critical aspect to the developmental cycle. A key system involved in protein turnover in bacteria is the Clp protease system. Here, we characterized the two chlamydial ClpP paralogs by examining their expression inChlamydiaspp., their ability to oligomerize, and their proteolytic activity. This work will help understand the evolutionarily diverse Clp proteases in the context of intracellular organisms, which may aid in the study of other clinically relevant intracellular bacteria.

scholarly journals The Repeat-In-Toxin Family Member TosA Mediates Adherence of Uropathogenic Escherichia coli and Survival during Bacteremia

2011 ◽  
Vol 80 (2) ◽  
pp. 493-505 ◽  
Author(s):  
Patrick D. Vigil ◽  
Travis J. Wiles ◽  
Michael D. Engstrom ◽  
Lev Prasov ◽  
Matthew A. Mulvey ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factors ◽  
Upper Urinary Tract ◽  
Host Cells ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Novel Target ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) is responsible for the majority of uncomplicated urinary tract infections (UTI) and represents the most common bacterial infection in adults. UPEC utilizes a wide range of virulence factors to colonize the host, including the novel repeat-in-toxin (RTX) protein TosA, which is specifically expressed in the host urinary tract and contributes significantly to the virulence and survival of UPEC.tosA, found in strains within the B2 phylogenetic subgroup ofE. coli, serves as a marker for strains that also contain a large number of well-characterized UPEC virulence factors. The presence oftosAin anE. coliisolate predicts successful colonization of the murine model of ascending UTI, regardless of the source of the isolate. Here, a detailed analysis of the function oftosArevealed that this gene is transcriptionally linked to genes encoding a conserved type 1 secretion system similar to other RTX family members. TosA localized to the cell surface and was found to mediate (i) adherence to host cells derived from the upper urinary tract and (ii) survival in disseminated infections and (iii) to enhance lethality during sepsis (as assessed in two different animal models of infection). An experimental vaccine, using purified TosA, protected vaccinated animals against urosepsis. From this work, it was concluded that TosA belongs to a novel group of RTX proteins that mediate adherence and host damage during UTI and urosepsis and could be a novel target for the development of therapeutics to treat ascending UTIs.

scholarly journals In Vitro Activity of Lefamulin against Sexually Transmitted Bacterial Pathogens

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Susanne Paukner ◽  
Astrid Gruss ◽  
Jørgen Skov Jensen
Keyword(s):  
Chlamydia Trachomatis ◽  
Bacterial Pathogens ◽  
Mycoplasma Genitalium ◽  
Standard Of Care ◽  
Multidrug Resistant ◽  
In Vitro Activity ◽  
First Line ◽  
Content Type ◽  
Sexually Transmitted

ABSTRACT The pleuromutilin antibiotic lefamulin demonstrated in vitro activity against the most relevant bacterial pathogens causing sexually transmitted infections (STI), including Chlamydia trachomatis (MIC 50/90 , 0.02/0.04 mg/liter; n = 15), susceptible and multidrug-resistant Mycoplasma genitalium (MIC range, 0.002 to 0.063 mg/liter; n = 6), and susceptible and resistant Neisseria gonorrhoeae (MIC 50/90 , 0.12/0.5 mg/liter; n = 25). The results suggest that lefamulin could be a promising first-line antibiotic for the treatment of STI, particularly in populations with high rates of resistance to standard-of-care antibiotics.

scholarly journals Levels ofMycoplasma genitaliumAntimicrobial Resistance Differ by Both Region and Gender in the State of Queensland, Australia: Implications for Treatment Guidelines

2019 ◽  
Vol 57 (3) ◽  
Author(s):  
E. L. Sweeney ◽  
E. Trembizki ◽  
C. Bletchly ◽  
C. S. Bradshaw ◽  
A. Menon ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Treatment Guidelines ◽  
Mycoplasma Genitalium ◽  
Macrolide Resistance ◽  
Quinolone Resistance ◽  
Resistance Mutations ◽  
Transmitted Infection ◽  
Content Type ◽  
Sexually Transmitted ◽  
And Gender

ABSTRACTMycoplasma genitaliumis frequently associated with urogenital and rectal infections, with the number of cases of macrolide-resistant and quinolone-resistantM. genitaliuminfection continuing to increase. In this study, we examined the levels of resistance to these two common antibiotic treatments in geographically distinct locations in Queensland, Australia. Samples were screened for macrolide resistance-associated mutations using a commercially available kit (ResistancePlus MG; SpeeDx), and quinolone resistance-associated mutations were identified by PCR and DNA sequencing. Comparisons between antibiotic resistance mutations and location/gender were performed. The levels ofM. genitaliummacrolide resistance were high across both locations (62%). Quinolone resistance mutations were found in ∼10% of all samples, with a number of samples harboring mutations conferring resistance to both macrolides and quinolones. Quinolone resistance was higher in southeast Queensland than in north Queensland, and this was consistent in both males and females (P = 0.007). TheM. genitaliumisolates in rectal swab samples from males harbored high levels of macrolide (75.9%) and quinolone (19%) resistance, with 15.5% harboring resistance to both classes of antibiotics. Overall, the lowest observed level of resistance was to quinolones in females from north Queensland (1.6%). These data highlight the high levels of antibiotic resistance inM. genitaliumisolates within Queensland and the challenges faced by sexually transmitted infection clinicians in managing these infections. The data do, however, show that the levels of antibiotic resistance may differ between populations within the same state, which has implications for clinical management and treatment guidelines. These findings also support the need for ongoing antibiotic resistance surveillance and tailored treatment.

scholarly journals Seroprevalence of Antibodies against Pkn1, a Novel Potential Immunogen, inChlamydia trachomatis-InfectedMacaca nemestrinaand Human Patients

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Achchhe L. Patel ◽  
Prashant K. Mishra ◽  
Divya Sachdev ◽  
Uma Chaudhary ◽  
Dorothy L. Patton ◽  
...  
Keyword(s):  
Immune Responses ◽  
Genital Tract ◽  
Protein A ◽  
Macaca Nemestrina ◽  
Sexually Transmitted ◽  
Host Immune Responses ◽  
Bioinformatic Tools ◽  
Genital Tract Infections ◽  
Tract Infections

Chlamydia trachomatis(CT) is an important cause of sexually transmitted genital tract infections (STIs) and trachoma. Despite major research into chlamydial pathogenesis and host immune responses, immunoprotection has been hampered by the incomplete understanding of protective immunity in the genital tract. Characterized vaccine candidates have shown variable efficacy ranging from no protection to partial protectionin vivo. It is therefore a research priority to identify novel chlamydial antigens that may elicit protective immune responses against CT infection. In the present study we assessed the seroprevalence of antibodies against protein kinase1 (Pkn1), DNA ligaseA (LigA), and major outer membrane protein A (OmpA) following natural CT infection in humans and in experimentally induced CT infection inMacaca nemestrina. Antigenic stretches of Pkn1, LigA, and OmpA were identified using bioinformatic tools.Pkn1,LigA, andOmpAgenes were cloned in bacterial expression vector and purified by affinity chromatography. Our results demonstrate significantly high seroprevalence of antibodies against purified Pkn1 and OmpA in sera obtained from the macaque animal model and human patients infected with CT. In contrast no significant seroreactivity was observed for LigA. The seroprevalence of antibodies against Pkn1 suggest that nonsurface chlamydial proteins could also be important for developing vaccines forC. trachomatis.

scholarly journals Structure and Metal Binding Properties of Chlamydia trachomatis YtgA

2019 ◽  
Vol 202 (1) ◽  
Author(s):  
Zhenyao Luo ◽  
Stephanie L. Neville ◽  
Rebecca Campbell ◽  
Jacqueline R. Morey ◽  
Shruti Menon ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Transition Metal ◽  
Metal Binding ◽  
Developed Countries ◽  
Biochemical Properties ◽  
Host Cells ◽  
Transmitted Infection ◽  
Content Type ◽  
Sexually Transmitted ◽  
Serious Disease

Chlamydia trachomatis is the most common bacterial sexually transmitted infection in developed countries, with an estimated global prevalence of 4.2% in the 15- to 49-year age group. Although infection is asymptomatic in more than 80% of infected women, about 10% of cases result in serious disease. Infection by C. trachomatis is dependent on the ability to acquire essential nutrients, such as the transition metal iron, from host cells. In this study, we show that iron is the most abundant transition metal in C. trachomatis and report the structural and biochemical properties of the iron-recruiting protein YtgA. Knowledge of the high-resolution structure of YtgA will provide a platform for future structure-based antimicrobial design approaches.

scholarly journals Mycoplasma genitalium Detection in Urogenital Specimens from Symptomatic and Asymptomatic Men and Women by Use of the cobas TV/MG Test

2020 ◽  
Vol 58 (6) ◽  
Author(s):  
Barbara Van Der Pol ◽  
Ken B. Waites ◽  
Li Xiao ◽  
Stephanie N. Taylor ◽  
Arundhati Rao ◽  
...  
Keyword(s):  
United States ◽  
Trichomonas Vaginalis ◽  
Mycoplasma Genitalium ◽  
The United States ◽  
Clinical Samples ◽  
Men And Women ◽  
Content Type ◽  
Sexually Transmitted ◽  
Asymptomatic Individuals ◽  
Asymptomatic Men

ABSTRACT Mycoplasma genitalium (MG) infections are a growing concern within the field of sexually transmitted infections. However, diagnostic assays for M. genitalium have been limited in the United States. As most infections are asymptomatic, individuals can unknowingly pass the infection on, and the prevalence is likely to be underestimated. Diagnosis of M. genitalium infection is recommended using a nucleic acid test. This multicenter study assessed the performance of the cobas Trichomonas vaginalis (TV)/MG assay (cobas) for the detection of M. genitalium, using 22,150 urogenital specimens from both symptomatic and asymptomatic men and women collected at geographically diverse sites across the United States. The performance was compared to a reference standard of three laboratory-developed tests (LDTs). The specificity of the cobas assay for M. genitalium ranged from 96.0% to 99.8% across symptomatic and asymptomatic men and women. The sensitivities in female vaginal swabs and urine samples were 96.6% (95% confidence interval [CI], 88.5 to 99.1%) and 86.4% (95% CI, 75.5 to 93.0%), respectively. The sensitivities in male urine and meatal swab samples were 100% (95% CI, 94.0 to 100%) and 85.0% (95% CI, 73.9 to 91.9%), respectively. This study demonstrated that the cobas assay was highly sensitive and specific in all relevant clinical samples for the detection of M. genitalium.

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