RESUMEN
Pediculus humanus capitis is a small ectoparasitic insect that has lived and feds on human beings for thousands of years. Molecular techniques have been used for Pediculus species identification and evolutionary, phylogenic, and ecological studies. A total of 23 adults of P. h. capitis were collected in Gaziantep, located in southeast Turkey, and DNA was isolated from all P. h. capitis using DNA extraction kit. All DNA samples were screened for investigate of Ricettsia prowazekii, Bartonella quintana and Borrelia recurrentis with real-time polymerase chain reaction. In addition, we investigated genetic variation in DNA samples of Pediculus humanus capitis using the cytochrome oxidase I genetic DNA sequence. We found 4 (17.4%) Ricettsia prowazekii and 3 (13.1%) Bartonella quintana in DNA samples of Pediculus humanus capitis, while we did not find any Bartonella recurrentis in any of the DNA samples. We demonstrated 1.8% genetic variations in DNA samples of Pediculus humanus capitis with Bartonella quintana. The phylogenetic tree based on the cytochrome oxidase I gene revealed that P. h. capitis in southeast Turkey are classified into two clades (clade A, clade B) and Bartonella quintana was found in only clade B. However, we did not find any genetic variations in other DNA samples in this region. The genetic variations may be related to P. h.capitis vector of Bartonella quintana has found in this study. In addition, this study was shown that P. h. capitis do transmit Rickettsia prowazekii and Bartonella quintana to people, epidemic typhus and trench fever may emergence in Gaziantep southeast of Turkey in the future.
Asunto(s)
Salud Pública , Fiebre de las Trincheras/epidemiología , Tifus Epidémico Transmitido por Piojos/epidemiología , Adulto , Animales , Bartonella quintana/aislamiento & purificación , Humanos , Pediculus/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Rickettsia prowazekii/aislamiento & purificación , Riesgo , Fiebre de las Trincheras/genética , Turquía/epidemiología , Tifus Epidémico Transmitido por Piojos/genéticaRESUMEN
AbstractFlea-borne (murine) typhus is a global rickettsiosis caused by Rickettsia typhi. Although flea-borne typhus is no longer nationally notifiable, cases are reported for surveillance purposes in a few U.S. states. The infection is typically self-limiting, but may be severe or life-threatening in some patients. We performed a retrospective review of confirmed or probable cases of fatal flea-borne typhus reported to the Texas Department of State Health Services during 1985-2015. When available, medical charts were also examined. Eleven cases of fatal flea-borne typhus were identified. The median patient age was 62 years (range, 36-84 years) and 8 (73%) were male. Patients presented most commonly with fever (100%), nausea and vomiting (55%), and rash (55%). Respiratory (55%) and neurologic (45%) manifestations were also identified frequently. Laboratory abnormalities included thrombocytopenia (82%) and elevated hepatic transaminases (63%). Flea or animal contact before illness onset was frequently reported (55%). The median time from hospitalization to administration of a tetracycline-class drug was 4 days (range, 0-5 days). The median time from symptom onset to death was 14 days (range, 1-34 days). Flea-borne typhus can be a life-threatening disease if not treated in a timely manner with appropriate tetracycline-class antibiotics. Flea-borne typhus should be considered in febrile patients with animal or flea exposure and respiratory or neurologic symptoms of unknown etiology.
Asunto(s)
Rickettsia prowazekii/patogenicidad , Rickettsia typhi/patogenicidad , Tifus Endémico Transmitido por Pulgas/diagnóstico , Tifus Epidémico Transmitido por Piojos/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Animales , Antibacterianos/administración & dosificación , Exantema/diagnóstico , Exantema/fisiopatología , Resultado Fatal , Femenino , Fiebre/diagnóstico , Fiebre/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Náusea/diagnóstico , Náusea/fisiopatología , Rickettsia prowazekii/aislamiento & purificación , Rickettsia typhi/aislamiento & purificación , Texas , Trombocitopenia/diagnóstico , Trombocitopenia/fisiopatología , Tiempo de Tratamiento , Transaminasas/metabolismo , Insuficiencia del Tratamiento , Tifus Endémico Transmitido por Pulgas/tratamiento farmacológico , Tifus Endémico Transmitido por Pulgas/microbiología , Tifus Endémico Transmitido por Pulgas/patología , Tifus Epidémico Transmitido por Piojos/tratamiento farmacológico , Tifus Epidémico Transmitido por Piojos/microbiología , Tifus Epidémico Transmitido por Piojos/patología , Vómitos/diagnóstico , Vómitos/fisiopatologíaRESUMEN
AbstractRickettsial infections are recognized as important causes of fever throughout southeast Asia. Herein, we determined the seroprevalence to rickettsioses within rural and urban populations of northern Vietnam. Prevalence of individuals with evidence of prior rickettsial infections (IgG positive) was surprisingly low, with 9.14% (83/908) testing positive to the three major rickettsial serogroups thought to circulate in the region. Prevalence of typhus group rickettsiae (TG)-specific antibodies (6.5%, 58/908) was significantly greater than scrub typhus group orientiae (STG)- or spotted fever group rickettsiae (SFG)-specific antibodies (P < 0.05). The majority of TG seropositives were observed among urban rather than rural residents (P < 0.05). In contrast, overall antibody prevalence to STG and SFG were both very low (1.1%, 10/908 for STG; 1.7%, 15/908 for SFG), with no significant differences between rural and urban residents. These results provide data on baseline population characteristics that may help inform development of Rickettsia serological testing criteria in future clinical studies.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Infecciones por Rickettsia/epidemiología , Tifus por Ácaros/epidemiología , Tifus Epidémico Transmitido por Piojos/epidemiología , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Orientia tsutsugamushi/clasificación , Orientia tsutsugamushi/aislamiento & purificación , Prevalencia , Rickettsia/clasificación , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/sangre , Infecciones por Rickettsia/diagnóstico , Rickettsia prowazekii/clasificación , Rickettsia prowazekii/aislamiento & purificación , Población Rural , Tifus por Ácaros/sangre , Tifus por Ácaros/diagnóstico , Estudios Seroepidemiológicos , Serotipificación , Tifus Epidémico Transmitido por Piojos/sangre , Tifus Epidémico Transmitido por Piojos/diagnóstico , Población Urbana , Vietnam/epidemiologíaRESUMEN
Epidemic typhus caused by Rickettsia prowazekii is one of the oldest pestilential diseases of humankind. The disease is transmitted to human beings by the body louse Pediculus humanus corporis and is still considered a major threat by public health authorities, despite the efficacy of antibiotics, because poor sanitary conditions are conducive to louse proliferation. Epidemic typhus has accompanied disasters that impact humanity and has arguably determined the outcome of more wars than have soldiers and generals. The detection, identification, and characterization of microorganisms in ancient remains by paleomicrobiology has permitted the diagnosis of past epidemic typhus outbreaks through the detection of R. prowazekii. Various techniques, including microscopy and immunodetection, can be used in paleomicrobiology, but most of the data have been obtained by using PCR-based molecular techniques on dental pulp samples. Paleomicrobiology enabled the identification of the first outbreak of epidemic typhus in the 18th century in the context of a pan-European great war in the city of Douai, France, and supported the hypothesis that typhus was imported into Europe by Spanish soldiers returning from America. R. prowazekii was also detected in the remains of soldiers of Napoleon's Grand Army in Vilnius, Lithuania, which indicates that Napoleon's soldiers had epidemic typhus. The purpose of this article is to underscore the modern comprehension of clinical epidemic typhus, focus on the historical relationships of the disease, and examine the use of paleomicrobiology in the detection of past epidemic typhus outbreaks.
Asunto(s)
Brotes de Enfermedades , Fósiles/microbiología , Paleopatología/métodos , Rickettsia prowazekii/aislamiento & purificación , Tifus Epidémico Transmitido por Piojos/epidemiología , Tifus Epidémico Transmitido por Piojos/historia , Animales , Técnicas Bacteriológicas/métodos , Salud Global , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Pediculus/crecimiento & desarrollo , Pediculus/microbiología , Reacción en Cadena de la Polimerasa/métodos , Rickettsia prowazekii/genéticaRESUMEN
In August 2012, laboratory tests confirmed a mixed outbreak of epidemic typhus fever and trench fever in a male youth rehabilitation center in western Rwanda. Seventy-six suspected cases and 118 controls were enrolled into an unmatched case-control study to identify risk factors for symptomatic illness during the outbreak. A suspected case was fever or history of fever, from April 2012, in a resident of the rehabilitation center. In total, 199 suspected cases from a population of 1,910 male youth (attack rate = 10.4%) with seven deaths (case fatality rate = 3.5%) were reported. After multivariate analysis, history of seeing lice in clothing (adjusted odds ratio [aOR] = 2.6, 95% confidence interval [CI] = 1.1-5.8), delayed (≥ 2 days) washing of clothing (aOR = 4.0, 95% CI = 1.6-9.6), and delayed (≥ 1 month) washing of beddings (aOR = 4.6, 95% CI = 2.0-11) were associated with illness, whereas having stayed in the rehabilitation camp for ≥ 6 months was protective (aOR = 0.20, 95% CI = 0.10-0.40). Stronger surveillance and improvements in hygiene could prevent future outbreaks.
Asunto(s)
Bartonella quintana/aislamiento & purificación , Brotes de Enfermedades , Phthiraptera/microbiología , Rickettsia prowazekii/aislamiento & purificación , Fiebre de las Trincheras/epidemiología , Tifus Epidémico Transmitido por Piojos/epidemiología , Adolescente , Adulto , Animales , Bartonella quintana/patogenicidad , Estudios de Casos y Controles , Coinfección , Humanos , Incidencia , Masculino , Oportunidad Relativa , Centros de Rehabilitación , Rickettsia prowazekii/patogenicidad , Factores de Riesgo , Rwanda/epidemiología , Análisis de Supervivencia , Fiebre de las Trincheras/diagnóstico , Fiebre de las Trincheras/mortalidad , Fiebre de las Trincheras/transmisión , Tifus Epidémico Transmitido por Piojos/diagnóstico , Tifus Epidémico Transmitido por Piojos/mortalidad , Tifus Epidémico Transmitido por Piojos/transmisiónRESUMEN
Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate intracellular bacterium that replicates only within the cytosol of a eukaryotic host cell. Despite the barriers to genetic manipulation that such a life style creates, rickettsial mutants have been generated by transposon insertion as well as by homologous recombination mechanisms. However, progress is hampered by the length of time required to identify and isolate R. prowazekii transformants. To reduce the time required and variability associated with propagation and harvesting of rickettsiae for each transformation experiment, characterized frozen stocks were used to generate electrocompetent rickettsiae. Transformation experiments employing these rickettsiae established that fluorescent rickettsial populations could be identified using a fluorescence activated cell sorter within one week following electroporation. Early detection was improved with increasing amounts of transforming DNA. In addition, we demonstrate that heterogeneous populations of rickettsiae-infected cells can be sorted into distinct sub-populations based on the number of rickettsiae per cell. Together our data suggest the combination of fluorescent reporters and cell sorting represent an important technical advance that will facilitate isolation of distinct R. prowazekii mutants and allow for closer examination of the effects of infection on host cells at various infectious burdens.
Asunto(s)
Separación Celular/métodos , Rickettsia prowazekii/aislamiento & purificación , Animales , Fluorescencia , Proteínas Fluorescentes Verdes/genética , RatonesRESUMEN
Sylvatic typhus is an infrequent, potentially life-threatening emerging zoonotic disease. In January of 2009, the New York State Department of Health was notified of a familial cluster of two suspected cases. Due to the paucity of typhus cases in New York, epidemiologic and environmental investigations were conducted to establish rickettsial etiology and determine potential sources of infection. Patients presented with symptoms consistent with typhus, and serologic testing of each patient confirmed infection with typhus group rickettsiae. Serologic analysis of blood obtained from southern flying squirrels (Glaucomys volans) captured from the attic crawlspace above an enclosed front porch of the cases' residence indicated evidence of infection with Rickettsia prowazekii, with 100% seroprevalence (n=11). Both patients reported spending significant time on the porch and hearing animal activity above the ceiling prior to onset of illness, implicating these flying squirrels as the likely source of infection.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Inmunoglobulina G/sangre , Rickettsia prowazekii/inmunología , Sciuridae/microbiología , Tifus Epidémico Transmitido por Piojos/epidemiología , Animales , Reservorios de Enfermedades , Femenino , Humanos , Masculino , Persona de Mediana Edad , New York/epidemiología , Rickettsia prowazekii/aislamiento & purificación , Estudios Seroepidemiológicos , Tifus Epidémico Transmitido por Piojos/microbiología , Adulto Joven , ZoonosisAsunto(s)
Antibacterianos/administración & dosificación , Reservorios de Enfermedades , Inmunoglobulina G/sangre , Rickettsia prowazekii , Tifus Epidémico Transmitido por Piojos , Zoonosis , Animales , Distribución de Chi-Cuadrado , Cloranfenicol/administración & dosificación , Reservorios de Enfermedades/microbiología , Reservorios de Enfermedades/estadística & datos numéricos , Ensayo de Inmunoadsorción Enzimática , Humanos , Rickettsia prowazekii/efectos de los fármacos , Rickettsia prowazekii/aislamiento & purificación , Factores de Riesgo , Sciuridae/microbiología , Determinación de Anticuerpos Séricos Bactericidas/métodos , Determinación de Anticuerpos Séricos Bactericidas/estadística & datos numéricos , Tetraciclina/administración & dosificación , Tifus Epidémico Transmitido por Piojos/diagnóstico , Tifus Epidémico Transmitido por Piojos/epidemiología , Tifus Epidémico Transmitido por Piojos/microbiología , Tifus Epidémico Transmitido por Piojos/fisiopatología , Tifus Epidémico Transmitido por Piojos/transmisión , Estados Unidos/epidemiología , Zoonosis/epidemiología , Zoonosis/microbiología , Zoonosis/transmisiónAsunto(s)
Infestaciones por Piojos/complicaciones , Pediculus/microbiología , Phthirus/microbiología , Fiebre Recurrente/transmisión , Fiebre de las Trincheras/transmisión , Tifus Epidémico Transmitido por Piojos/transmisión , Animales , Bartonella quintana/aislamiento & purificación , Ropa de Cama y Ropa Blanca , Vestuario , Reservorios de Enfermedades , Fiebre/etiología , Francia/epidemiología , Personas con Mala Vivienda , Humanos , Higiene , Huésped Inmunocomprometido , Mordeduras y Picaduras de Insectos/microbiología , Infestaciones por Piojos/epidemiología , Infestaciones por Piojos/prevención & control , Fiebre Recurrente/diagnóstico , Fiebre Recurrente/epidemiología , Fiebre Recurrente/prevención & control , Rickettsia prowazekii/aislamiento & purificación , Sepsis/etiología , Sepsis/microbiología , Condiciones Sociales , Fiebre de las Trincheras/diagnóstico , Fiebre de las Trincheras/epidemiología , Fiebre de las Trincheras/prevención & control , Tifus Epidémico Transmitido por Piojos/diagnóstico , Tifus Epidémico Transmitido por Piojos/epidemiología , Tifus Epidémico Transmitido por Piojos/prevención & control , Poblaciones VulnerablesRESUMEN
Recrudescent Rickettsia prowazekii infection, also known as Brill-Zinsser disease, can manifest decades after untreated primary infection but is rare in contemporary settings. We report the first known case of Brill-Zinsser disease in a patient originally infected with a zoonotic strain of R. prowazekii acquired from flying squirrels.
Asunto(s)
Rickettsia prowazekii/aislamiento & purificación , Sciuridae/microbiología , Tifus Epidémico Transmitido por Piojos/diagnóstico , Anciano , Animales , Anticuerpos Antibacterianos/sangre , Humanos , Inmunoglobulina G/sangre , Masculino , Tifus Epidémico Transmitido por Piojos/patología , Estados Unidos , Zoonosis/transmisiónRESUMEN
Brill-Zinsser disease, the relapsing form of epidemic typhus, typically occurs in a susceptible host years or decades after the primary infection; however, the mechanisms of reactivation and the cellular reservoir during latency are poorly understood. Herein we describe a murine model for Brill-Zinsser disease, and use PCR and cell culture to show transient rickettsemia in mice treated with dexamethasone >3 months after clinical recovery from the primary infection. Treatment of similarly infected mice with cyclosporine failed to produce recrudescent bacteremia. Therapy with doxycycline for the primary infection prevented recrudescent bacteremia in most of these mice following treatment with dexamethasone. Rickettsia prowazekii (the etiologic agent of epidemic typhus) was detected by PCR, cell culture, and immunostaining methods in murine adipose tissue, but not in liver, spleen, lung, or central nervous system tissues of mice 4 months after recovery from the primary infection. The lungs of dexamethasone-treated mice showed impaired expression of beta-defensin transcripts that may be involved in the pathogenesis of pulmonary lesions. In vitro, R. prowazekii rickettsiae infected and replicated in the murine adipocyte cell line 3T3-L1. Collectively these data suggest a role for adipose tissue as a potential reservoir for dormant infections with R. prowazekii.
Asunto(s)
Tejido Adiposo/microbiología , Modelos Animales de Enfermedad , Rickettsia prowazekii/aislamiento & purificación , Tifus Epidémico Transmitido por Piojos/microbiología , Animales , Secuencia de Bases , Cartilla de ADN , Dexametasona/uso terapéutico , Femenino , Pulmón/metabolismo , Ratones , Ratones Endogámicos BALB C , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tifus Epidémico Transmitido por Piojos/tratamiento farmacológico , Tifus Epidémico Transmitido por Piojos/metabolismo , beta-Defensinas/metabolismoAsunto(s)
Bartonella quintana/aislamiento & purificación , Infestaciones por Piojos/parasitología , Pediculus/microbiología , Animales , Proteínas Bacterianas/genética , ADN Bacteriano/genética , ADN Espaciador Ribosómico/genética , Glutamato Sintasa/genética , Humanos , México , Reacción en Cadena de la Polimerasa , Prevalencia , Rickettsia prowazekii/aislamiento & purificaciónRESUMEN
In February 2006, a diagnosis of sylvatic epidemic typhus in a counselor at a wilderness camp in Pennsylvania prompted a retrospective investigation. From January 2004 through January 2006, 3 more cases were identified. All had been counselors at the camp and had experienced febrile illness with myalgia, chills, and sweats; 2 had been hospitalized. All patients had slept in the same cabin and reported having seen and heard flying squirrels inside the wall adjacent to their bed. Serum from each patient had evidence of infection with Rickettsia prowazekii. Analysis of blood and tissue from 14 southern flying squirrels trapped in the woodlands around the cabin indicated that 71% were infected with R. prowazekii. Education and control measures to exclude flying squirrels from housing are essential to reduce the likelihood of sylvatic epidemic typhus.
Asunto(s)
Sciuridae/microbiología , Tifus Epidémico Transmitido por Piojos/epidemiología , Adulto , Animales , Reservorios de Enfermedades , Educación Médica Continua , Humanos , Entrevistas como Asunto , Masculino , Pennsylvania , Rickettsia prowazekii/aislamiento & purificación , Encuestas y Cuestionarios , Tifus Epidémico Transmitido por Piojos/complicaciones , Tifus Epidémico Transmitido por Piojos/transmisiónRESUMEN
Genetic traits of five Rickettsia prowazekii isolates, including the first from Africa and North America, and representatives from human and flying squirrels were compared using multilocus sequence typing. Four rickettsial genes encoding 17 kDa genus-common antigen (17 kDa gene), citrate synthase (gltA), OmpB immunodominant antigen (ompB) and 120 kDa cytoplasmic antigen (sca4) were examined. Sequence identities of 17 kDa gene and gltA were 100% among the isolates. Limited sequence diversity of ompB (0.02-0.11%) and sca4 (0.03-0.20%) was enough to distinguish the isolates, and evaluation of the combined four genes provided a method to easily differentiate R. prowazekii from other rickettsiae.
Asunto(s)
Rickettsia prowazekii/clasificación , Rickettsia prowazekii/genética , Tifus Epidémico Transmitido por Piojos/microbiología , Animales , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Secuencia de Bases , ADN Bacteriano/genética , Humanos , Datos de Secuencia Molecular , Rickettsia prowazekii/aislamiento & purificación , Sciuridae , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Tifus Epidémico Transmitido por Piojos/veterinariaRESUMEN
The presence of R. prowazekii in lice using R. prowazekii-specific qPCR cassettes showed the changes of the rickettsial burden in the lice post-infection.
Asunto(s)
Phthiraptera/microbiología , Reacción en Cadena de la Polimerasa/métodos , Rickettsia prowazekii/genética , Tifus Epidémico Transmitido por Piojos/diagnóstico , Animales , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Modelos Animales de Enfermedad , Rickettsia prowazekii/aislamiento & purificaciónRESUMEN
Rickettsia prowazekii is the causative agent of epidemic typhus and a potential bioterrorism agent. Sensitive and specific rapid assays are needed to complement existing methods of detecting this organism. We developed a real-time quantitative polymerase chain reaction assay by using a species-specific probe targeting the gltA gene. This assay, which was rapid, specific for R. prowazekii only, and sensitive (cutoff detection of 1 to 5 copies per sample), detected and directly identified R. prowazekii in blood of 12 experimentally infected mice sampled at day 3 and 6 postinfection or in naturally or experimentally infected lice. Because our assay is highly standardized and easily adaptable, it could improve epidemic typhus surveillance in public health programs, especially for countries with underdiagnosed or unrecognized human cases.
Asunto(s)
Reacción en Cadena de la Polimerasa/métodos , Rickettsia prowazekii/genética , Rickettsia prowazekii/aislamiento & purificación , Animales , Proteínas Bacterianas/genética , Chlorocebus aethiops , Femenino , Ratones , Ratones Endogámicos BALB C , Phthiraptera/microbiología , Sensibilidad y Especificidad , Especificidad de la Especie , Células VeroRESUMEN
BACKGROUND: Many soldiers in Napoleon's Grand Army died of infectious diseases during its retreat from Russia. Because soldiers were commonly infested with body lice, it has been speculated that louse-borne infectious diseases, such as epidemic typhus (caused by Rickettsia prowazekii), were common. METHODS: We investigated this possibility during recent excavations of a mass grave of Napoleon's soldiers in Vilnius, Lithuania. Segments of 5 body lice, identified morphologically and by polymerase chain reaction (PCR) amplification and sequencing, were found in earth from the grave that also contained fragments of soldiers' uniforms. RESULTS: DNA of Bartonella quintana (the agent of trench fever) was identified by PCR and sequencing in 3 of the lice. Similarly, PCR and sequencing of dental pulp from the remains of 35 soldiers revealed DNA of B. quintana in 7 soldiers and DNA of R. prowazekii in 3 other soldiers. CONCLUSIONS: Our results show that louse-borne infectious diseases affected nearly one-third of Napoleon's soldiers buried in Vilnius and indicate that these diseases might have been a major factor in the French retreat from Russia.
Asunto(s)
Bartonella quintana/aislamiento & purificación , Infestaciones por Piojos/historia , Personal Militar/historia , Rickettsia prowazekii/aislamiento & purificación , Fiebre de las Trincheras/historia , Tifus Epidémico Transmitido por Piojos/historia , Animales , Bartonella quintana/clasificación , Bartonella quintana/genética , Secuencia de Bases , ADN Bacteriano/análisis , Pulpa Dental/microbiología , Francia/epidemiología , Historia del Siglo XIX , Humanos , Infestaciones por Piojos/complicaciones , Infestaciones por Piojos/epidemiología , Lituania/epidemiología , Masculino , Datos de Secuencia Molecular , Paleodontología , Pediculus/microbiología , Reacción en Cadena de la Polimerasa , Rickettsia prowazekii/clasificación , Rickettsia prowazekii/genética , Análisis de Secuencia de ADN , Fiebre de las Trincheras/epidemiología , Tifus Epidémico Transmitido por Piojos/epidemiologíaRESUMEN
OBJECTIVE: To develop a quantitative real-time polymerase chain reaction (PCR) for detecting Rickettsia prowazekii. METHODS: Primers and TaqMan-MGB probes designed based on ompB gene of R. prowazekii, were used to develop this method. RESULTS: For the quantitative real-time PCR, the relationship between the values of threshold cycle (Ct) and the DNA copy number was linear (r = 0.999) and the sensitivity was about 100 times higher than that of the nested PCR for detecting the same DNA sample. The results of the genomic DNA samples of other rickettsial and bacterial agents detected by real-time PCR were all negative. DNAs extracted from blood samples of guinea pig infected with R. prowazekii were examined by real-time PCR and the positive results were obtained from some of these samples. However, the results of some samples in nested PCR assay were all negative. CONCLUSION: These results suggested that the real-time PCR was highly specific and sensitive for detection of R. prowazekii that was useful for the detection of tiny DNA of R. prowazekii in blood samples from patients suspected of having epidemic typhus.
Asunto(s)
Reacción en Cadena de la Polimerasa/métodos , Rickettsia prowazekii/genética , Cartilla de ADN , ADN Bacteriano/análisis , Humanos , Rickettsia prowazekii/aislamiento & purificación , Sensibilidad y Especificidad , Tifus Epidémico Transmitido por Piojos/diagnósticoRESUMEN
Currently, there is no tool for typing Rickettsia prowazekii, the causative agent of epidemic typhus, currently considered a potential bioterrorism agent, at the strain level. To test if the multispacer typing (MST) method could differentiate strains of R. prowazekii, we amplified and sequenced the 25 most variable intergenic spacers between the R. prowazekii and R. conorii genomes in five strains and 10 body louse amplicons of R. prowazekii from various geographic origins. Two intergenic spacers, i.e., rpmE/tRNA(fMet) and serS/virB4, were variable among tested R. prowazekii isolates and allowed identification of three and two genotypes, respectively. When the genotypes obtained from the two spacers were combined, we identified four different genotypes. MST demonstrated that several R. prowazekii strains circulated in human body lice during an outbreak of epidemic typhus in Burundi. This may help to discriminate between natural and intentional outbreaks. Our study supports the usefulness of MST as a versatile method for rickettsial strain genotyping.
Asunto(s)
Técnicas de Tipificación Bacteriana , ADN Espaciador Ribosómico/análisis , Rickettsia prowazekii/clasificación , Tifus Epidémico Transmitido por Piojos/epidemiología , Animales , Proteínas Bacterianas , ADN Bacteriano , Brotes de Enfermedades , Variación Genética , Humanos , Datos de Secuencia Molecular , Phthiraptera/microbiología , Reacción en Cadena de la Polimerasa , Rickettsia prowazekii/genética , Rickettsia prowazekii/aislamiento & purificación , Análisis de Secuencia de ADN , Tifus Epidémico Transmitido por Piojos/microbiologíaRESUMEN
Species of the genus Rickettsia are small, obligate intracelular, gramnegative bacteria, many of which are considered nowadays a paradigm of emergent pathogens. With the exception of R. prowazekii, they are maintained in the natural environment through a cycle involving different hosts (mainly mammals), and arthropod vectors (in general ticks, and fleas); humans are affected only by incidental transmission due to arthropod bites. The common pathogenesis of these diseases lie on the predominantly infection of endotelial cells, that determines the development of multisistemic small vessel vasculitis, which may affect lungs (interstitial pneumonitis), heart (miopericarditis), skin (rash), central nervous system (meningoencephalitis), as well as liver, and kidneys. They are classified in two groups: spotted-fever group, and typhus group rickettsia. In Spain the most prevalent rickettsioses of both groups are mediterranean spotted fever (caused by R. conorii), and murine typhus (caused by R. typhi), respectively. This review focuses mainly in these two diseases, and also in other rickettsioses of interest due to their recently emergence or reemergence (R. slovaca, R. africae, R. prowazekii, R. felis), or to their high incidence in other areas (R. rickettsii, Orientia tsutsugamushi).