RESUMEN
The egress of intracellular bacteria from host cells and cellular tissues is a critical process during the infection cycle. This process is essential for bacteria to spread inside the host and can influence the outcome of an infection. For the obligate intracellular Gram-negative zoonotic bacterium Chlamydia psittaci, little is known about the mechanisms resulting in bacterial egress from the infected epithelium. Here, we describe and characterize Chlamydia-containing spheres (CCSs), a novel and predominant type of non-lytic egress utilized by Chlamydia spp. CCSs are spherical, low-phase contrast structures surrounded by a phosphatidylserine-exposing membrane with specific barrier functions. They contain infectious progeny and morphologically impaired cellular organelles. CCS formation is a sequential process starting with the proteolytic cleavage of a DEVD tetrapeptide-containing substrate that can be detected inside the chlamydial inclusions, followed by an increase in the intracellular calcium concentration of the infected cell. Subsequently, blebbing of the plasma membrane begins, the inclusion membrane destabilizes, and the proteolytic cleavage of a DEVD-containing substrate increases rapidly within the whole infected cell. Finally, infected, blebbing cells detach and leave the monolayer, thereby forming CCS. This sequence of events is unique for chlamydial CCS formation and fundamentally different from previously described Chlamydia egress pathways. Thus, CCS formation represents a major, previously uncharacterized egress pathway for intracellular pathogens that could be linked to Chlamydia biology in general and might influence the infection outcome in vivo.IMPORTANCEHost cell egress is essential for intracellular pathogens to spread within an organism and for host-to-host transmission. Here, we characterize Chlamydia-containing sphere (CCS) formation as a novel and predominant non-lytic egress pathway of the intracellular pathogens Chlamydia psittaci and Chlamydia trachomatis. CCS formation is fundamentally different from extrusion formation, the previously described non-lytic egress pathway of C. trachomatis. CCS formation is a unique sequential process, including proteolytic activity, followed by an increase in intracellular calcium concentration, inclusion membrane destabilization, plasma membrane blebbing, and the final detachment of a whole phosphatidylserine-exposing former host cell. Thus, CCS formation represents an important and previously uncharacterized egress pathway for intracellular pathogens that could possibly be linked to Chlamydia biology, including host tropism, protection from host cell defense mechanisms, or bacterial pathogenicity.
Asunto(s)
Chlamydophila psittaci , Chlamydophila psittaci/genética , Chlamydophila psittaci/fisiología , Humanos , Células HeLa , Cuerpos de Inclusión/microbiología , Cuerpos de Inclusión/metabolismo , Membrana Celular/metabolismo , Interacciones Huésped-Patógeno , Células Epiteliales/microbiología , Infecciones por Chlamydia/microbiologíaRESUMEN
Physcion, a natural anthraquinone derivative, has been reported to exert remarkable antibacterial activities against Staphylococcus aureus,Staphylococcus epidermidis and Pseudomonas aeruginosa. However, it is not fully illustrated as anti-Chlamydia substance. In the present study, minimum inhibitory concentration(MIC)values for physcion against Chlamydia psittaci(C.psittaci) 6BC, C.psittaci SBL and C.psittaci HJ were 128 µg/mL,256 µg/mL and 128 µg/mL while minimum bactericidal concentration (MBC) values were 256 µg/mL,512 µg/mL and 256 µg/mL,respectively. Moreover, Chlamydial adhesion to Hela 229 cells was blocked in a dose-dependent manner and RB-to-EB differentiation was inhibited by physcion from 28 to 48 hpi.Post treatment,upregulation of LC3-II was in a dose-dependent manner, indicating physcion activated autophagy and bacterial clearance.To validate clinical efficacy,49 SPF chickens aged 21days were divided into 5 groups and infected intra-laryngeally with 0.2 mL of 1 × 107 IFU/mL C.psittaci 6 BCE.Three days later, birds received orally with serial doses of physcion (4 mg/kg to 9 mg/kg), or 3 mg/kg of doxycycline for 6 days.Chickens with difficulty in breathing were alleviated significantly with increasing concentrations of physicon.Postmortem,lesions of air sacs were reduced significantly in a dose-dependent manner.More importantly,birds with 9 mg/kg of physcion could alleviate lesions of air sacs and lungs, and reduce bacterial loads in spleens, which was comparable to doxycycline treatment. Based on above evidences, physcion is a promising cost-effective natural drug by blocking Chlamydial adhesions to host cells, RB-to-EB differentiation and activating bacterial autophagy and it will be a good alternative to doxycycline combating virulent C.psittaci infection, contributing to eradication of Chlamydial transmission from animals to human beings.
Asunto(s)
Chlamydia , Chlamydophila psittaci , Psitacosis , Humanos , Animales , Chlamydophila psittaci/fisiología , Antraquinonas , Doxiciclina , Pollos , Psitacosis/microbiología , Psitacosis/veterinariaRESUMEN
Chlamydia psittaci is a multi-host zoonotic pathogen, which mainly infects poultry and inflicts an appreciable economic burden on the livestock farming industry. C. psittaci inclusion membrane proteins are uniquely positioned at the host-pathogen interface and are important virulence proteins. We have previously confirmed that Incs regulate host cell survival to help Chlamydia sp. evade host-cell-mediated defense mechanisms. However, the role of the Inc, CPSIT_0842, in the regulation of cell death following the establishment of persistent C. psittaci infection remains unknown. This study explored the effect of CPSIT_0842 on the crosstalk between the autophagic and apoptotic pathways in macrophages. Results showed that CPSIT_0842 initiated autophagy and blocked autophagic flux in human macrophages, as indicated by autophagy-related protein LC3-II, Beclin-1, and p62 upregulation, autophagosome accumulation, and lysosomal protein LAMP1 diminution. We also showed that the disruption of autophagic flux had a regulatory effect on CPSIT_0842-induced apoptosis. Moreover, the suppression of autophagy initiation by 3-methyladenine attenuated CPSIT_0842-induced apoptosis. By contrast, the induction of autophagic flux by rapamycin did not significantly affect CPSIT_0842-induced apoptosis. Taken together, these findings demonstrate that CPSIT_0842 induced macrophage apoptosis by initiating incomplete autophagy through the MAPK/ERK/mTOR signaling pathway, which may be instrumental to the ability of C. psittaci to evade the host innate immune response and establish persistent infection. The improved understanding of the autophagic and cell death pathways triggered upon bacterial inclusion will likely help in the development of novel treatment strategies for chlamydia infection.
Asunto(s)
Chlamydophila psittaci , Psitacosis , Humanos , Chlamydophila psittaci/fisiología , Proteínas de la Membrana , Psitacosis/metabolismo , Psitacosis/microbiología , Autofagia , ApoptosisRESUMEN
Presented is a patient with dyspnea and painful ulcers finally resulting in multi-organ failure. A detailed history resulted in positive PCR testing for Chlamydia psittaci. We emphasize the importance of a definitive history in establishing the correct diagnosis. When clinicians observe dyspnea with multi-organ failure, they should be aware of psittacosis.
Asunto(s)
Chlamydophila psittaci/fisiología , Insuficiencia Multiorgánica/complicaciones , Psitacosis/complicaciones , Chlamydophila psittaci/genética , Humanos , Necrosis/complicaciones , Reacción en Cadena de la Polimerasa , Psitacosis/diagnóstico , Psitacosis/patologíaRESUMEN
The zoonotic intracellular bacterium Chlamydia psittaci causes life-threatening pneumonia in humans. During mouse lung infection, complement factor C3 and the anaphylatoxin C3a augment protection against C. psittaci by a so far unknown mechanism. To clarify how complement contributes to the early, innate and the late, specific immune response and resulting protection, this study addresses the amount of C3, the timing when its presence is required as well as the anaphylatoxin receptor(s) mediating its effects and the complement-dependent migration of dendritic cells. Challenge experiments with C. psittaci on various complement KO mice were combined with transient decomplementation by pharmacological treatment, as well as the analysis of in vivo dendritic cells migration. Our findings reveal that a plasma concentration of C3 close to wildtype levels was required to achieve full protection. The diminished levels of C3 of heterozygote C3+/- mice permitted already relative effective protection and improved survival as compared to C3-/- mice, but overall recovery of these animals was delayed. Complement was in particular required during the first days of infection. However, additionally, it seems to support protection at later stages. Migration of CD103+ dendritic cells from the infected lung to the draining lymph node-as prerequisite of antigen presentation-depended on C3 and C3aR and/or C5aR. Our results provide unique mechanistic insight in various aspects of complement-dependent immune responses under almost identical, rather physiological experimental conditions. Our study contributes to an improved understanding of the role of complement, and C3a in particular, in infections by intracellular bacteria.
Asunto(s)
Movimiento Celular/inmunología , Infecciones por Chlamydiaceae/inmunología , Chlamydophila psittaci/inmunología , Complemento C3a/inmunología , Células Dendríticas/inmunología , Pulmón/inmunología , Anafilatoxinas/inmunología , Anafilatoxinas/metabolismo , Animales , Línea Celular , Infecciones por Chlamydiaceae/metabolismo , Infecciones por Chlamydiaceae/microbiología , Chlamydophila psittaci/fisiología , Activación de Complemento/inmunología , Complemento C3a/genética , Complemento C3a/metabolismo , Células Dendríticas/citología , Células Dendríticas/microbiología , Pulmón/metabolismo , Pulmón/microbiología , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Complemento/genética , Receptores de Complemento/inmunología , Receptores de Complemento/metabolismo , Transducción de Señal/inmunología , Análisis de SupervivenciaRESUMEN
Chlamydia psittaci is an obligate intracellular zoonotic pathogen that can enter a persistence state in host cells. While the exact pathogenesis is not well understood, this persistence state may play an important role in chronic Chlamydia disease. Here, we assess the effects of chlamydial persistence state in vitro and in vivo by transmission electron microscopy (TEM) and cDNA microarray assays. First, IFN-γ-induced C. psittaci persistence in HeLa cells resulted in the upregulation of 68 genes. These genes are involved in protein translation, carbohydrate metabolism, nucleotide metabolism, lipid metabolism and general stress. However, 109 genes were downregulated following persistent C. psittaci infection, many of which are involved in the TCA cycle, expression regulation and transcription, protein secretion, proteolysis and transport, membrane protein, presumed virulence factor, cell division and late expression. To further study differential gene expression of C. psittaci persistence in vivo, we established an experimentally tractable mouse model of C. psittaci persistence. The C. psittaci-infected mice were gavaged with either water or amoxicillin (amox), and the results indicated that the 20 mg/kg amox-exposed C. psittaci were viable but not infectious. Differentially expressed genes (DEGs) screened by cDNA microarray were detected, and interestingly, the results showed upregulation of three genes (euo, ahpC, prmC) and downregulation of five genes (pbp3, sucB_1, oppA_4, pmpH, ligA) in 20 mg/kg amox-exposed C. psittaci, which suggests that antibiotic treatment in vivo can induce chlamydial persistence state and lead to differential gene expression. However, the discrepancy on inducers between the two models requires more research to supplement. The results may help researchers better understand survival advantages during persistent infection and mechanisms influencing C. psittaci pathogenesis or evasion of the adaptive immune response.
Asunto(s)
Chlamydophila psittaci/fisiología , Psitacosis/metabolismo , Amoxicilina/administración & dosificación , Amoxicilina/uso terapéutico , Animales , Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Citocinas/genética , Citocinas/metabolismo , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Femenino , Regulación de la Expresión Génica/fisiología , Vida Libre de Gérmenes , Células HeLa , Humanos , Ratones , Ratones Endogámicos BALB C , Microscopía Electrónica de Transmisión , Psitacosis/tratamiento farmacológico , Psitacosis/inmunología , Psitacosis/microbiología , Transcriptoma , Regulación hacia ArribaRESUMEN
Chlamydia psittaci (C. psittaci) is an obligate intracellular, gram-negative bacterium, and mainly causes systemic disease in psittacine birds, domestic poultry, and wild fowl. The pathogen is threating to human beings due to closely contacted to employees in poultry industry. The polymorphic membrane proteins (Pmps) enriched in C. psittaci includes six subtypes (A, B/C, D, E/F, G/I and H). Compared to that of the 1 pmpG gene in Chlamydia trachomatis (C. trachomatis), the diverse pmpG gene-coding proteins of C. psittaci remain elusive. In the present study, polymorphic membrane protein 17G (Pmp17G) of C. psittaci mediated adhesion to different host cells. More importantly, expression of Pmp17G in C. trachomatis upregulated infections to host cells. Afterwards, crosstalk between Pmp17G and EGFR was screened and identified by MALDI-MS and Co-IP. Subsequently, EGFR overexpression in CHO-K1 cells and EGFR knockout in HeLa 229 cells were assessed to determine whether Pmp17G directly correlated with EGFR during Chlamydial adhesion. Finally, the EGFR phosphorylation was recognized by Grb2, triggering chlamydial invasion. Based on above evidence, Pmp17G possesses adhesive property that serves as an adhesin and activate intracellular bacterial internalization by recognizing EGFR during C. psittaci infection.
Asunto(s)
Chlamydophila psittaci/fisiología , Receptores ErbB/metabolismo , Interacciones Huésped-Patógeno , Proteínas de la Membrana/metabolismo , Psitacosis/metabolismo , Psitacosis/microbiología , Adhesión Celular , Línea Celular , Receptores ErbB/agonistas , Humanos , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/genética , Fosforilación , Unión ProteicaRESUMEN
Chlamydia psittaci (order: Chlamydiales) is a globally distributed zoonotic bacterium that can cause potentially fatal disease in birds and humans. Parrots are a major host, yet prevalence and risk factors for infection in wild parrots are largely unknown. Additionally, recent research suggests there is a diverse range of novel Chlamydiales circulating in wildlife. We therefore sampled seven abundant parrot species in south-eastern Australia, taking cloacal swabs and serum from n = 132 wild adults. We determined C. psittaci and Chlamydiales prevalence and seroprevalence, and tested for host species, sex, geographical and seasonal differences, and temporal changes in individual infection status. Across all species, Chlamydiales prevalence was 39.8% (95% CI 31.6, 48.7), C. psittaci prevalence was 9.8% (95% CI 5.7, 16.3) and C. gallinacea prevalence was 0.8% (95% CI 0.1, 4.5). Other Chlamydiales species were not identified to species level. We identified two C. psittaci strains within the 6BC clade, which is highly virulent in humans. Seroprevalence was 37.0% (95% CI 28.5, 46.4). Host species (including crimson rosellas, galahs, sulphur-crested cockatoos and blue-winged parrots) differed in seroprevalence and Chlamydiales prevalence. Galahs had both highest Chlamydiales prevalence (54.8%) and seroprevalence (74.1%). Seroprevalence differed between sites, with a larger difference in males (range 20-63%) than females (29-44%). We reveal a higher chlamydial prevalence than previously reported in many wild parrots, with implications for potential reservoirs, and transmission risks to humans and other avian hosts.
Asunto(s)
Enfermedades de las Aves/epidemiología , Enfermedades de las Aves/microbiología , Chlamydophila psittaci/fisiología , Geografía , Loros/microbiología , Psitacosis/epidemiología , Psitacosis/veterinaria , Caracteres Sexuales , Animales , Femenino , Interacciones Huésped-Patógeno , Masculino , Prevalencia , Estaciones del Año , Estudios Seroepidemiológicos , Especificidad de la Especie , Factores de TiempoRESUMEN
PURPOSE: Chlamydia psittaci infection in humans can lead to serious clinical manifestations, including severe pneumonia, adult respiratory distress syndrome, and, rarely, death. Implementation of metagenomic next-generation sequencing (mNGS) gives a promising new tool for diagnosis. The clinical spectrum of severe psittacosis pneumonia is described to provide physicians with a better understanding and to highlight the rarity and severity of severe psittacosis pneumonia. METHODS: Nine cases of severe psittacosis pneumonia were diagnosed using mNGS. Retrospective analysis of the data on disease progression, new diagnosis tool, treatments, and outcomes, and the findings were summarised. RESULTS: Frequent symptoms included chills and remittent fever (100%), cough and hypodynamia (100%), and headache and myalgia (77.8%). All patients were severe psittacosis pneumonia developed respiratory failure, accompanied by sepsis in 6/9 patients. mNGS takes 48-72 h to provide the results, and help to identify diagnosis of psittacosis. Laboratory data showed normal or slightly increased leucocytes, neutrophils, and procalcitonin but high C-reactive protein levels. Computed tomography revealed air-space consolidation and ground-glass opacity, which began in the upper lobe of one lung, and spread to both lungs, along with miliary, nodular, or consolidated shadows. One patient died because of secondary infection with Klebsiella pneumoniae, while the other eight patients experienced complete recoveries. CONCLUSIONS: The use of mNGS can improve accuracy and reduce the delay in diagnosis of psittacosis. Severe psittacosis pneumonia responds well to the timely use of appropriate antibiotics.
Asunto(s)
Chlamydophila psittaci/fisiología , Neumonía/diagnóstico , Psitacosis/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Masculino , Metagenómica , Persona de Mediana Edad , Neumonía/microbiología , Psitacosis/complicaciones , Psitacosis/microbiología , Estudios RetrospectivosRESUMEN
Chlamydophila psittaci (C. psittaci) is an avian pathogen associated with systemic wasting disease in birds, as well as a public health risk. Although duck-related cases of psittacosis have been reported, the pathogenicity and shedding status of C. psittaci in ducks are unclear. In this study, we reported that C. psittaci (genotype A) is responsible for a disease outbreak characterized by poor laying performance and severe lesions in multiple organs of ducks. Oral administration of antibiotic, doxycycline, was found to effectively control the C. psittaci infection in laying ducks. Collectively, our new findings provide evidence that C. psittaci was the major pathogen responsible for the outbreak of this disease in ducks. In order to reduce economic losses incurred by this disease, effective control measures must be taken to prevent infection in laying duck farms.
Asunto(s)
Chlamydophila psittaci/fisiología , Patos , Enfermedades de las Aves de Corral/patología , Psitacosis/patología , Animales , Antibacterianos/administración & dosificación , China , Chlamydophila psittaci/clasificación , Chlamydophila psittaci/efectos de los fármacos , Doxiciclina/administración & dosificación , Femenino , Enfermedades de las Aves de Corral/tratamiento farmacológico , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/fisiopatología , Psitacosis/tratamiento farmacológico , Psitacosis/microbiología , Psitacosis/fisiopatología , ReproducciónRESUMEN
The present study evaluated the immune-protective efficacy of the Chlamydia psittaci (C. psittaci) plasmid protein CPSIT_p7 and analyzed the potential mechanisms of this protection. The current study used recombinant CPSIT_p7 protein with Freund's complete adjuvant and Freund's incomplete adjuvant to vaccinate BALB/c mice. Adjuvants alone or PBS formulated with the same adjuvants was used as negative controls. Mice were intranasally challenged with 105 inclusion-forming units (IFU) of C. psittaci. We found that CPSIT_p7 vaccination significantly decreased the mouse lung chlamydial load, interferon-γ (IFN-γ) level, and pathological injury. This protection correlated well with specific humoral and cellular immune responses against C. psittaci. In vitro or in vivo neutralization of C. psittaci with sera harvested from immunized mice did not reduce the number of recoverable C. psittaci in the infected lungs, but CD4+ spleen cells collected from CPSIT_p7-immunized mice significantly decreased the chlamydial load via adoptive transfer to native mice. These results reveal that the protection conferred by CPSIT_p7 is dependent on CD4+ T cells.
Asunto(s)
Antígenos Bacterianos/inmunología , Vacunas Bacterianas/inmunología , Linfocitos T CD4-Positivos/inmunología , Chlamydophila psittaci/fisiología , Pulmón/patología , Psitacosis/inmunología , Vacunas Sintéticas/inmunología , Animales , Antígenos Bacterianos/genética , Carga Bacteriana , Femenino , Inmunidad Celular , Inmunización , Interferón gamma/sangre , Pulmón/microbiología , Ratones , Ratones Endogámicos BALB C , Plásmidos/genética , VacunaciónRESUMEN
Psittacosis (infection with Chlamydia psittaci) can have diverse presentations in humans, ranging from asymptomatic infection to severe systemic disease. Awareness of psittacosis and its presentations are low among clinicians and the general public. Therefore, underdiagnosis and thereby underestimation of the incidence and public health importance of psittacosis is very likely. We used the methodology developed for the Burden of communicable diseases in Europe toolkit of the European Centre for Disease Prevention and Control, to construct a model to estimate disease burden in disability-adjusted life years (DALYs) attributable to psittacosis. Using this model, we estimated the disease burden caused by psittacosis in the Netherlands to have been 222 DALY per year (95% CI 172-280) over the period 2012-2014. This is comparable with the amount of DALYs estimated to be due to rubella or shigellosis in the same period in the Netherlands. Our results highlight the public health importance of psittacosis and identify evidence gaps pertaining to the clinical presentations and prognosis of this disease.
Asunto(s)
Chlamydophila psittaci/fisiología , Costo de Enfermedad , Psitacosis/epidemiología , Años de Vida Ajustados por Calidad de Vida , Humanos , Incidencia , Modelos Teóricos , Países Bajos/epidemiología , Psitacosis/microbiologíaRESUMEN
The JAK-STAT3 signaling pathway is a key regulator of cell growth, motility, migration, invasion and apoptosis in mammalian cells. Infection with intracellular pathogens of the genus Chlamydia can inhibit host cell apoptosis, and here we asked whether the JAK-STAT3 pathway participates in chlamydial anti-apoptotic activity. We found that, compared with uninfected cells, levels of JAK1 and STAT3 mRNA as well as total and phosphorylated JAK1 and STAT3 protein, were significantly increased in C. psittaci-infected HeLa cells. Moreover, the apoptosis rate of infected cells was higher after treatment with the tyrosine kinase inhibitor AG-490 (2-cyano-3-(3, 4-dihydroxyphenyl)-N-(phenylmethyl)-2-propenamide). Immunoblotting of apoptosis-related proteins showed that C. psittaci infection reduces Bax, but increases Bcl-2, protein levels, resulting in reduced activation of caspase-3, caspase-7, caspase-9 and PARP; AG490 attenuates these effects. Together, our data suggest that the JAK/STAT3 signaling pathway facilitates the anti-apoptotic effect of C. psittaci infection by reducing the Bax/Bcl-2 apoptotic switch ratio, and by inhibiting the intracellular activation of key pro-apoptotic enzymes.
Asunto(s)
Apoptosis , Chlamydophila psittaci/fisiología , Quinasas Janus/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Apoptosis/genética , Caspasas/metabolismo , Células Cultivadas , Expresión Génica , Células HeLa , Interacciones Huésped-Patógeno/genética , Humanos , Quinasas Janus/genética , Poli(ADP-Ribosa) Polimerasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Psitacosis/genética , Psitacosis/metabolismo , Psitacosis/microbiología , Factor de Transcripción STAT3/genética , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Chlamydia psittaci, an obligate intracellular gram-negative bacteria, causes an important zoonotic disease in humans, namely, psittacosis. The objective of this study was to determine the persistent viability of C. psittaci at various temperature conditions. The cloacal swab samples were collected from feral and racing pigeons to find a C. psittaci field strain. The bacterial isolation showed that 1.3% of feral pigeons were PCR positive, while all samples of racing pigeons were PCR negative. Also, bacterial characterization suggested that it belonged to genotype B, which had bacterial titers 3.2 and 3.89 log 50% lethal dose/ml, respectively. A bacterial persistence test was performed, and the results showed that C. psittaci could survive at 56 C for up to 72 hr. In conclusion, C. psittaci could be found in feral pigeons in central Thailand. The bacteria can survive in equatorial temperature areas. This study was the first to report that C. psittaci could survive and has infectivity at 56 C for 72 hr. Therefore, awareness of C. psittaci infection in humans is necessary and should be a public health concern.
Asunto(s)
Enfermedades de las Aves/microbiología , Chlamydophila psittaci/fisiología , Psitacosis/veterinaria , Animales , Aves , Chlamydophila psittaci/clasificación , Chlamydophila psittaci/genética , Chlamydophila psittaci/aislamiento & purificación , Columbidae/microbiología , Genotipo , Filogenia , Reacción en Cadena de la Polimerasa , Psitacosis/microbiología , Temperatura , TailandiaRESUMEN
Eggshell penetration by pathogens is considered a potential route for their transmission in poultry flocks. Additionally, in case of zoonotic pathogens, contact with infected eggs or their consumption can result in human infection. Chlamydia psittaci is a zoonotic bacterium that causes a respiratory disease in poultry and humans. In this study, we provide an experimental evidence for eggshell penetration by C. psittaci. Additionally, we show that after eggshell penetration, C. psittaci could eventually infect the growing embryo. Our findings portend the potential of horizontal trans-shell transmission as a possible route for the spread of C. psittaci infection in poultry flocks. Considering that horizontal transmission of pathogens via eggs mainly occurs in hatcheries and hatching cabinets, we suggest the latter as critical control points in the transmission of C. psittaci to hatching chicks and broilers, as well as to the hatchery workers and consumers of table eggs.
Asunto(s)
Pollos , Chlamydophila psittaci/fisiología , Enfermedades de las Aves de Corral/transmisión , Psitacosis/veterinaria , Animales , Cáscara de Huevo/microbiología , Enfermedades de las Aves de Corral/microbiología , Psitacosis/microbiología , Psitacosis/transmisiónRESUMEN
Chlamydia psittaci causes psittacosis/ornithosis in birds and is an economically important pathogen for poultry farming. It also infects nonavian domestic animals as well as rodents, and is a zoonotic human pathogen responsible for atypical pneumonia. The bacterium efficiently disseminates in host organisms causing pulmonary and systemic disease. Its rapid entry, fast replication cycle, and tight control of intracellular transport routes contribute to the host-to-host transmission and efficient growth observed with C. psittaci. Recent studies have revealed that the pathogen copes better than other chlamydial strains with proinflammatory effectors produced during the early immune reaction of infected hosts. These features likely contribute to successful infections and might explain the potent adaptation and evasion characteristics of the agent. Current findings on cell-autonomous, innate, and adaptive defenses against C. psittaci provide novel insights into the concerted immune mechanisms involved in the clearance of the pathogen. Further in-depth studies on C. psittaci and other related agents in cellular as well as animal models are needed to develop more efficient antichlamydial therapies and vaccination strategies.
Asunto(s)
Chlamydophila psittaci/fisiología , Chlamydophila psittaci/patogenicidad , Psitacosis/transmisión , Adaptación Fisiológica , Animales , Chlamydophila psittaci/genética , Genoma Bacteriano , Interacciones Huésped-Patógeno , Humanos , Evasión Inmune , Psitacosis/inmunología , Psitacosis/veterinariaRESUMEN
Enteric infections caused by Chlamydia (C.) psittaci are frequent in ducks, but mostly remain subclinical under field conditions. To emulate natural infection, we investigated the pathogenic potential of a C. psittaci field strain in orally inoculated 4-day-old ducklings. Three different challenge doses were tested and seven contact animals were also mock-inoculated with buffer in each group. Over the course of ten days, the birds were monitored for clinical symptoms and chlamydial dissemination before final examination of tissues using histopathology and immunohistochemistry. While the challenge strain disseminated systemically to all internal organs, mild signs of diarrhea were confined to ducklings inoculated with the highest dose (4.3 x 108 IFU/mL, Group 1). No other clinical symptoms or histopathological lesions were seen. The chlamydial load in internal organs as measured by PCR depended on the challenge dose and was unevenly distributed, i.e. high loads in spleen, liver, and distal small and large intestinal tract (ileum, cecum and rectum) vs. ten times lower values in lungs and proximal small intestinal tract (duodenum and jejunum). Notably, the C. psittaci infection of contact birds became evident on day 10 post-infection, with bacterial loads comparable to those of experimentally-infected animals, thus suggesting rapid bird-to-bird transmission of the challenge strain.
Asunto(s)
Chlamydophila psittaci/fisiología , Patos/microbiología , Psitacosis/transmisión , Psitacosis/veterinaria , Animales , Carga Bacteriana , Chlamydophila psittaci/genética , Chlamydophila psittaci/aislamiento & purificación , Inmunohistoquímica , Especificidad de Órganos , Psitacosis/microbiología , Psitacosis/patologíaRESUMEN
Chlamydia (C.) psittaci is an economically relevant pathogen in poultry and pet birds, where it causes psittacosis/ornithosis, and also a human pathogen causing atypical pneumonia after zoonotic transmission. Despite its well-documented prevalence, the agent has received less attention by researchers than other Chlamydia spp. in the last decades. In the present paper, we review recently published data on C. psittaci infection and attempt to single out characteristic features distinguishing it from related chlamydial agents. It is remarkable that C. psittaci is particularly efficient in disseminating in the host organism causing systemic disease, which occasionally can take a fulminant course. At the cellular level, the pathogen's broad host cell spectrum (from epithelial cells to macrophages), its rapid entry and fast replication, proficient use of intracellular transport routes to mitochondria and the Golgi apparatus, the pronounced physical association of chlamydial inclusions with energy-providing cell compartments, as well as the subversive regulation of host cell survival during productive and persistent states facilitate the characteristic efficient growth and successful host-to-host spread of C. psittaci. At the molecular level, the pathogen was shown to upregulate essential chlamydial genes when facing the host immune response. We hypothesize that this capacity, in concert with expression of specific effectors of the type III secretion system and efficient suppression of selected host defense signals, contributes to successful establishment of the infection in the host. Concerning the immunology of host-pathogen interactions, C. psittaci has been shown to distinguish itself by coping more efficiently than other chlamydiae with pro-inflammatory mediators during early host response, which can, to some extent, explain the effective evasion and adaptation strategies of this bacterium. We conclude that thorough analysis of the large number of whole-genome sequences already available will be essential to identify genetic markers of the species-specific features and trigger more in-depth studies in cellular and animal models to address such vital topics as treatment and vaccination.
Asunto(s)
Chlamydophila psittaci/fisiología , Interacciones Huésped-Patógeno , Animales , Aves , Chlamydophila psittaci/inmunología , Genoma Bacteriano , Humanos , Factores de Virulencia/genética , Factores de Virulencia/metabolismoRESUMEN
Chlamydia (C.) psittaci, the causative agent of ornithosis, is an obligate intracellular pathogen with a unique developmental cycle and a high potential for zoonotic transmission. Various mammalian hosts, such as cattle, horse, sheep and man that are in close contact with contaminated birds can get infected (referred to as psittacosis). Since little is known about long-term sequelae of chronic disease and the molecular mechanisms of chlamydial pathogenesis, a key step in understanding the in vivo situation is the identification of C. psittaci infection-associated proteins. For this, we investigated sera of infected calves. Using the immunoscreening approach In Vivo Induced Antigen Technology (IVIAT) including all relevant controls, we focused on C. psittaci proteins, which are induced in vivo during infection. Sera were pooled, extensively adsorbed against in vitro antigens to eliminate false positive results, and used to screen an inducible C. psittaci 02DC15 genomic expression library. Screening and control experiments revealed 19 immunogenic proteins, which are expressed during infection. They are involved in transport and oxidative stress response, heme and folate biosynthesis, DNA replication, recombination and repair, cell envelope, bacterial secretion systems and hypothetical proteins of so far unknown functions. Some of the proteins found may be considered as diagnostic markers or as candidates for the development of vaccines.
Asunto(s)
Antígenos Bacterianos/biosíntesis , Proteínas Bacterianas/biosíntesis , Infecciones por Chlamydia/veterinaria , Chlamydophila psittaci/fisiología , Perfilación de la Expresión Génica , Regulación Bacteriana de la Expresión Génica , Activación Transcripcional , Animales , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Bovinos , Infecciones por Chlamydia/microbiología , Chlamydophila psittaci/genética , Pulmón/microbiologíaRESUMEN
PURPOSE: To compare genome-wide DNA methylation profiles according to Chlamydophila psittaci (Cp) infection status and the response to doxycycline treatment in Korean patients with ocular adnexal extranodal marginal zone B-cell lymphoma (EMZL). METHODS: Twelve ocular adnexal EMZL cases were classified into two groups (six Cp-positive cases and six Cp-negative cases). Among the 12 cases, eight were treated with doxycycline as first-line therapy, and they were divided into two groups according to their response to the treatment (four doxy-responders and four doxy-nonresponders). The differences in the DNA methylation states of 27,578 methylation sites in 14,000 genes were evaluated using Illumina bead assay technology. We also validated the top-ranking differentially methylated genes (DMGs) with bisulfite direct sequencing or pyrosequencing. RESULTS: The Infinium methylation chip assay revealed 180 DMGs in the Cp-positive group (74 hypermethylated genes and 106 hypomethylated genes) compared to the Cp-negative group. Among the 180 DMGs, DUSP22, which had two significantly hypomethylated loci, was validated, and the correlation was significant for one CpG site (Spearman coefficient=0.6478, p=0.0262). Regarding the response to doxycycline treatment, a total of 778 DMGs were revealed (389 hypermethylated genes and 336 hypomethylated genes in the doxy-responder group). In a subsequent replication study for representative hypomethylated (IRAK1) and hypermethylated (CXCL6) genes, the correlation between the bead chip analysis and pyrosequencing was significant (Spearman coefficient=0.8961 and 0.7619, respectively, p<0.05). CONCLUSIONS: Ocular adnexal EMZL showed distinct methylation patterns according to Cp infection and the response to doxycycline treatment in this genome-wide methylation study. Among the candidate genes, DUSP22 has a methylation status that was likely attributable to Cp infection. Our data also suggest that the methylation statuses of IRAK1 and CXCL6 may reflect the response to doxycycline treatment.