RESUMEN
The diagnosis of Lyme neuroborreliosis (LNB) is based on neurological symptoms, cerebrospinal fluid (CSF) pleocytosis, and intrathecally produced Borrelia-specific antibodies. In most cases, the presence of intrathecally produced Borrelia-specific antibodies is determined by using an enzyme-linked immunosorbent assay (ELISA). The edge effect is a known phenomenon in ELISAs and can negatively influence the assay reproducibility and repeatability, as well as index calculations of sample pairs which are tested in the same run. For LNB diagnostics, an index calculation is used for which the relative amounts of Borrelia-specific antibodies in CSF and serum are measured to calculate a CSF/serum quotient, which is needed to calculate the Borrelia-specific antibody index (AI). The presence of an edge effect in an ELISA used for LNB diagnostics may thus have implications. In this study, we investigated the intra-assay variation of the commercial Enzygnost Lyme link VlsE/IgG ELISA used for LNB diagnostics and showed the presence of an edge effect. Minor adaptations in the ELISA protocol decreased this effect. The adapted protocol was subsequently used to test 149 CSF-serum pairs of consecutive patients received in a routine diagnostic laboratory. By simulation, we showed that, if the standard protocol would have been used, then the edge effect for this study population could have resulted in 15 (10.1%) false-pathological and two (1.3%) false-normal Borrelia-specific IgG AIs. Thus, the observed edge effect can lead to inaccurate LNB diagnoses. Our study underlines that the edge effect should be investigated when ELISAs are implemented in routine diagnostics, as this phenomenon can occur in any ELISA.
Asunto(s)
Neuroborreliosis de Lyme , Anticuerpos Antibacterianos , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunoglobulina M , Neuroborreliosis de Lyme/diagnóstico , Reproducibilidad de los ResultadosRESUMEN
Recent studies have shown elevated levels of the B-cell chemokine (C-X-C motif) ligand 13 (CXCL13) in the cerebrospinal fluid (CSF) of patients with early Lyme neuroborreliosis (LNB). In this retrospective study, we evaluated the diagnostic performance of the Quantikine CXCL13 enzyme-linked immunosorbent assay (ELISA) (R&D Systems, Inc., MN, USA) and the recomBead CXCL13 assay (Mikrogen, Neuried, Germany) for the detection of CXCL13 in CSF. All consecutive patients from whom a CSF and a serum sample had been collected between August 2013 and June 2016 were eligible for inclusion. Patients suspected of LNB were classified as definite, possible, or non-LNB according to the guidelines of the European Federation of Neurological Societies (EFNS). Due to the limited number of LNB patients in the predefined study period, additional LNB patients were included from outside this period. In total, 156 patients (150 consecutive patients and 6 additional LNB patients) were included. Seven (4.5%) were classified as definite, eight (5.1%) as possible, and 141 (90.4%) as non-LNB patients. Receiver operating characteristic (ROC) curve analysis comparing definite-LNB patients with non-LNB patients showed a cutoff value of 85.9 pg/ml for the Quantikine CXCL13 ELISA and 252.2 pg/ml for the recomBead CXCL13 assay. The corresponding sensitivity was 100% (95% confidence interval [CI], 100% to 100%) for both, and the corresponding specificities were 98.6% (95% CI, 96.5% to 100%) for the CXCL13 ELISA and 97.2% (95% CI, 93.6% to 100%) for the recomBead CXCL13 assay. This study showed that CXCL13 in CSF can be of additional value for the diagnosis of LNB.
Asunto(s)
Neuroborreliosis de Lyme , Quimiocina CXCL13 , Ensayo de Inmunoadsorción Enzimática , Humanos , Pruebas Inmunológicas , Neuroborreliosis de Lyme/diagnóstico , Curva ROC , Estudios RetrospectivosRESUMEN
Young children cannot easily produce sputum for diagnosis of pulmonary tuberculosis (TB). Alternatively, Mycobacterium tuberculosis complex bacilli can be detected in stool by using the Xpert MTB/RIF (Ultra) assay (Xpert). Published stool processing methods contain somewhat complex procedures and require additional supplies. The aim of this study was to develop a simple one-step (SOS) stool processing method based on gravity sedimentation only, similar to Xpert testing of sputum samples, for the detection of M. tuberculosis in stool samples. We first assessed whether the SOS stool method could provide valid Xpert results without the need for bead-beating, dilution, and filtration steps. We concluded that this was the case, and we then validated the SOS stool method by testing spiked stool samples. By using the SOS stool method, 27 of the 29 spiked samples gave valid Xpert results, and M. tuberculosis was recovered from all 27 samples. The proof of principle of the SOS stool method was demonstrated in routine settings in Addis Ababa, Ethiopia. Nine of 123 children with presumptive TB had M. tuberculosis-positive results for nasogastric aspiration (NGA) samples, and 7 (77.8%) of those children also had M. tuberculosis-positive Xpert results for stool samples. Additionally, M. tuberculosis was detected in the stool samples but not the NGA samples from 2 children. The SOS stool processing method makes use of the standard Xpert assay kit, without the need for additional supplies or equipment. The method can potentially be rolled out to any Xpert site, bringing a bacteriologically confirmed diagnosis of TB in children closer to the point of care.
Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Preescolar , Etiopía , Humanos , Mycobacterium tuberculosis/genética , Sistemas de Atención de Punto , Sensibilidad y Especificidad , Esputo , Tuberculosis/diagnósticoRESUMEN
Lyme disease is a common multisystem disease caused by infection with a tick-transmitted spirochete, Borrelia burgdorferi and related Borrelia species. The monoglycosylated diacylglycerol known as B. burgdorferi glycolipid II (BbGL-II) is a major target of antibodies in sera from infected individuals. Here, we show that CD1b presents BbGL-II to human T cells and that the TCR mediates the recognition. However, we did not detect increased frequency of CD1b-BbGL-II binding T cells in the peripheral blood of Lyme disease patients compared to controls. Unexpectedly, mapping the T cell specificity for BbGL-II-like molecules using tetramers and activation assays revealed a concomitant response to CD1b-expressing APCs in absence of BbGL-II. Further, among all major classes of self-lipid tested, BbGL-II responsive TCRs show strong cross-reactivity to diacylglycerol, a self-lipid antigen with structural similarities to BbGL-II. Extending prior work on MHC and CD1b, CD1c, and CD1d proteins, this study provides evidence for cross-reactive CD1b-restricted T cell responses to bacterial and self-antigens, and identifies chemically defined targets for future discovery of self and foreign antigen cross-reactive T cells.
Asunto(s)
Presentación de Antígeno/inmunología , Antígenos CD1/metabolismo , Borrelia burgdorferi/inmunología , Enfermedad de Lyme/inmunología , Enfermedad de Lyme/metabolismo , Linfocitos T/inmunología , Linfocitos T/metabolismo , Antígenos Bacterianos/inmunología , Autoantígenos/inmunología , Reacciones Cruzadas/inmunología , Diglicéridos/inmunología , Epítopos de Linfocito T/inmunología , Humanos , Enfermedad de Lyme/microbiología , Activación de Linfocitos/inmunología , Unión Proteica , Receptores de Antígenos de Linfocitos T/química , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismoRESUMEN
BACKGROUND: After antibiotic treatment of Lyme borreliosis, a subset of patients report persistent symptoms, also referred to as post-treatment Lyme disease syndrome. The reported prevalence of persistent symptoms varies considerably, and its pathophysiology is under debate. The LymeProspect study has been designed to investigate the prevalence, severity, and a wide range of hypotheses on the etiology of persistent symptoms among patients treated for Lyme borreliosis in the Netherlands. METHODS: LymeProspect is a prospective, observational cohort study among adults with proven or probable Lyme borreliosis, either erythema migrans or disseminated manifestations, included at the start of antibiotic treatment. During one year of follow-up, participants are subjected to questionnaires every three months and blood is collected repeatedly during the first three months. The primary outcome is the prevalence of persistent symptoms after treatment, assessed by questionnaires online focusing on fatigue (CIS, subscale fatigue severity), pain (SF-36, subscale pain) and neurocognitive dysfunction (CFQ). Potential microbiological, immunological, genetic, epidemiological and cognitive-behavioral determinants for persistent symptoms are secondary outcome measures. Control cohorts include patients with long-lasting symptoms and unconfirmed Lyme disease, population controls, and subjects having reported a tick bite not followed by Lyme borreliosis. DISCUSSION: This article describes the background and design of the LymeProspect study protocol. This study is characterized by a prospective, explorative and multifaceted design. The results of this study will provide insights into the prevalence and determinants of persistent symptoms after treatment for Lyme borreliosis, and may provide a rationale for preventive and treatment recommendations. TRIAL REGISTRATION: NTR4998 (Netherlands Trial Register). Date of registration: 13 February 2015.
Asunto(s)
Enfermedad de Lyme/tratamiento farmacológico , Enfermedad de Lyme/epidemiología , Adulto , Anciano , Animales , Antibacterianos/uso terapéutico , Mordeduras y Picaduras/complicaciones , Protocolos Clínicos , Estudios de Cohortes , Eritema Crónico Migrans/tratamiento farmacológico , Eritema Crónico Migrans/epidemiología , Eritema Crónico Migrans/etiología , Fatiga/etiología , Humanos , Enfermedad de Lyme/etiología , Persona de Mediana Edad , Países Bajos/epidemiología , Prevalencia , Estudios Prospectivos , Encuestas y Cuestionarios , GarrapatasRESUMEN
To review the latest information about levels of anti-tuberculosis (TB) drug resistance in the European Region of the World Health Organization (WHO) and time-trends in multidrug-resistant TB (resistance to isoniazid and rifampicin; MDR-TB) over the past fifteen years. We analysed data on drug resistance among new and previously treated TB cases reported from 1997 to 2012. Data are collected in surveys of representative samples of TB patients or from surveillance systems based on diagnostic drug susceptibility testing. A total of 15.7% (95% confidence limits (CI): 9.5-21.9) of new and 45.3% (95%CI: 39.2-51.5) of previously treated TB cases are estimated to have MDR-TB in the Region. Extensively drug-resistant TB (MDR-TB and resistance to fluoroquinolones and second-line injectables; XDR-TB) had been reported by 38 of the 53 countries of the region (72%). The proportion of MDR-TB cases with XDR-TB is 11.4% (95%CI: 8.6-14.2). Between 1997 and 2012, population rates of MDR-TB declined in Estonia, Latvia and Germany and increased in the United Kingdom, Sweden and Tomsk Oblasts of the Russian Federation. Surveillance of drug resistance has been strengthened in the WHO European Region, which has the highest proportions of MDR-TB and XDR-TB ever reported globally. More complete data are needed particularly from the Russian Federation.
Asunto(s)
Antituberculosos/farmacología , Tuberculosis Extensivamente Resistente a Drogas/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Europa (Continente)/epidemiología , Tuberculosis Extensivamente Resistente a Drogas/tratamiento farmacológico , Humanos , Isoniazida/farmacología , Pruebas de Sensibilidad Microbiana , Vigilancia de la Población , Rifampin/farmacología , Factores de Tiempo , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Organización Mundial de la SaludRESUMEN
BACKGROUND: In Vietnam, the Mycobacterium tuberculosis Beijing genotype is associated with multi-drug resistance and is emerging. A possible explanation for this genotype's success is an increased rate of relapse. METHODS: In a prospective cohort study, isolates from patients with smear-positive tuberculosis were subjected to drug susceptibility testing and to spoligotyping and variable number of tandem repeats typing before treatment and after recurrence of tuberculosis. RESULTS: Among 1068 patients who were actively followed up over 18 months for recurrence, 23 relapse cases occurred (1.39 cases/100 person-years). After adjustment for genotype, tuberculosis treatment history, and drug resistance, relapse was significantly associated with the Beijing genotype (adjusted hazard ratio [aHR], 5.48; 95% confidence interval [CI], 2.06-14.55) and isoniazid resistance (aHR, 5.91; 95% CI, 2.16-16.16). CONCLUSIONS: The strongly increased relapse rate in tuberculosis cases caused by Beijing strains probably contributes to the successful spread of this genotype in Vietnam and elsewhere.
Asunto(s)
Mycobacterium tuberculosis/aislamiento & purificación , Mycobacterium tuberculosis/patogenicidad , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/prevención & control , Adulto , Anciano , Antituberculosos/uso terapéutico , Estudios de Cohortes , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Femenino , Estudios de Seguimiento , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/genética , Niacina/uso terapéutico , Prevalencia , Estudios Prospectivos , Recurrencia , Rifampin/uso terapéutico , Población Rural , Estreptomicina/uso terapéutico , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Vietnam/epidemiologíaRESUMEN
Isoniazid resistance is highly prevalent in Vietnam. We investigated the molecular and epidemiological characteristics and the association with first-line treatment outcomes of the main isoniazid resistance mutations in Mycobacterium tuberculosis in codon 315 of the katG and in the promoter region of the inhA gene. Mycobacterium tuberculosis strains with phenotypic resistance to isoniazid from consecutively diagnosed smear-positive tuberculosis patients in rural Vietnam were subjected to Genotype MTBDRplus testing to identify katG and inhA mutations. Treatment failure and relapse were determined by sputum culture. In total, 227 of 251 isoniazid-resistant strains (90.4%) had detectable mutations: 75.3% in katG codon 315 (katG315) and 28.2% in the inhA promoter region. katG315 mutations were significantly associated with pretreatment resistance to streptomycin, rifampin, and ethambutol but not with the Beijing genotype and predicted both unfavorable treatment outcome (treatment failure or death) and relapse; inhA promoter region mutations were only associated with resistance to streptomycin and relapse. In tuberculosis patients, M. tuberculosis katG315 mutations but not inhA mutations are associated with unfavorable treatment outcome. inhA mutations do, however, increase the risk of relapse, at least with treatment regimens that contain only isoniazid and ethambutol in the continuation phase.
Asunto(s)
Antituberculosos/farmacología , Farmacorresistencia Bacteriana Múltiple , Isoniazida/farmacología , Mutación , Mycobacterium tuberculosis/genética , Tuberculosis/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Catalasa/genética , Catalasa/metabolismo , Codón , Etambutol/farmacología , Femenino , Estudios de Seguimiento , Genotipo , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/patogenicidad , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Regiones Promotoras Genéticas , Recurrencia , Rifampin/farmacología , Estreptomicina/farmacología , Resultado del Tratamiento , Tuberculosis/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Vietnam , Adulto JovenRESUMEN
In order to switch from IS6110 and polymorphic GC-rich repetitive sequence (PGRS) restriction fragment length polymorphism (RFLP) to 24-locus variable-number tandem-repeat (VNTR) typing of Mycobacterium tuberculosis complex isolates in the national tuberculosis control program in The Netherlands, a detailed evaluation on discriminatory power and agreement with findings in a cluster investigation was performed on 3,975 tuberculosis cases during the period of 2004 to 2008. The level of discrimination of the two typing methods did not differ substantially: RFLP typing yielded 2,733 distinct patterns compared to 2,607 in VNTR typing. The global concordance, defined as isolates labeled unique or identically distributed in clusters by both methods, amounted to 78.5% (n = 3,123). Of the remaining 855 cases, 12% (n = 479) of the cases were clustered only by VNTR, 7.7% (n = 305) only by RFLP typing, and 1.8% (n = 71) revealed different cluster compositions in the two approaches. A cluster investigation was performed for 87% (n = 1,462) of the cases clustered by RFLP. For the 740 cases with confirmed or presumed epidemiological links, 92% were concordant with VNTR typing. In contrast, only 64% of the 722 cases without an epidemiological link but clustered by RFLP typing were also clustered by VNTR typing. We conclude that VNTR typing has a discriminatory power equal to IS6110 RFLP typing but is in better agreement with findings in a cluster investigation performed on an RFLP-clustering-based cluster investigation. Both aspects make VNTR typing a suitable method for tuberculosis surveillance systems.
Asunto(s)
Elementos Transponibles de ADN , Repeticiones de Minisatélite , Tipificación Molecular/métodos , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/genética , Polimorfismo de Longitud del Fragmento de Restricción , Análisis por Conglomerados , ADN Bacteriano/genética , Humanos , Epidemiología Molecular/métodos , Mycobacterium tuberculosis/aislamiento & purificación , Países Bajos , Tuberculosis/microbiologíaRESUMEN
BACKGROUND: In comparison to restriction fragment length polymorphism (RFLP) typing, variable number of tandem repeat (VNTR) typing is easier to perform, faster and yields results in a simple, numerical format. Therefore, this technique has gained recognition as the new international gold standard in typing of Mycobacterium tuberculosis. However, some reports indicated that VNTR typing may be less suitable for Beijing genotype isolates. We therefore compared the performance of internationally standardized RFLP and 24 loci VNTR typing to discriminate among 100 Beijing genotype isolates from the Southern Vietnam. METHODS: Hundred Beijing genotype strains defined by spoligotyping were randomly selected and typed by RFLP and VNTR typing. The discriminatory power of VNTR and RFLP typing was compared using the Bionumerics software. RESULTS: Among 95 Beijing strains available for analysis, 14 clusters were identified comprising 34 strains and 61 unique profiles in 24 loci VNTR typing ((Hunter Gaston Discrimination Index (HGDI = 0.994)). 13 clusters containing 31 strains and 64 unique patterns in RFLP typing (HGDI = 0.994) were found. Nine RFLP clusters were subdivided by VNTR typing and 12 VNTR clusters were split by RFLP. Five isolates (5%) revealing double alleles or no signal in two or more loci in VNTR typing could not be analyzed. CONCLUSIONS: Overall, 24 loci VNTR typing and RFLP typing had similar high-level of discrimination among 95 Beijing strains from Southern Vietnam. However, loci VNTR 154, VNTR 2461 and VNTR 3171 had hardly added any value to the level of discrimination.
Asunto(s)
Genotipo , Repeticiones de Minisatélite , Mycobacterium tuberculosis/genética , Polimorfismo de Longitud del Fragmento de Restricción , Análisis por Conglomerados , Femenino , Humanos , Masculino , Tipificación de Secuencias Multilocus , Mycobacterium tuberculosis/clasificación , VietnamRESUMEN
BACKGROUND: Mycobacterium tuberculosis is characterised by limited genomic diversity, which makes the application of whole genome sequencing particularly attractive for clinical and epidemiological investigation. However, in order to confidently infer transmission events, an accurate knowledge of the rate of change in the genome over relevant timescales is required. METHODS: We attempted to estimate a molecular clock by sequencing 199 isolates from epidemiologically linked tuberculosis cases, collected in the Netherlands spanning almost 16 years. RESULTS: Multiple analyses support an average mutation rate of ~0.3 SNPs per genome per year. However, all analyses revealed a very high degree of variation around this mean, making the confirmation of links proposed by epidemiology, and inference of novel links, difficult. Despite this, in some cases, the phylogenetic context of other strains provided evidence supporting the confident exclusion of previously inferred epidemiological links. CONCLUSIONS: This in-depth analysis of the molecular clock revealed that it is slow and variable over short time scales, which limits its usefulness in transmission studies. However, the superior resolution of whole genome sequencing can provide the phylogenetic context to allow the confident exclusion of possible transmission events previously inferred via traditional DNA fingerprinting techniques and epidemiological cluster investigation. Despite the slow generation of variation even at the whole genome level we conclude that the investigation of tuberculosis transmission will benefit greatly from routine whole genome sequencing.
Asunto(s)
Genoma Bacteriano , Mycobacterium tuberculosis/genética , Filogenia , Tuberculosis Pulmonar/transmisión , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Tasa de Mutación , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/aislamiento & purificación , Países Bajos/epidemiología , Polimorfismo de Nucleótido Simple , Factores de Tiempo , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/microbiologíaRESUMEN
PURPOSE: To provide an overview of the tuberculosis (TB) and multi-drug resistant tuberculosis (MDR-TB) in the WHO European Region and evolution of public health response with focus on extra-pulmonary tuberculosis and Pott's disease. METHODS: Authors reviewed regional strategic documents related to TB. The epidemiologic data were reviewed and analyzed. RESULTS: In the absence of associated pulmonary TB, Pott's disease is reported as extra-pulmonary TB (up to 47 % of all TB cases in some settings). Due to limitations of the surveillance system, the epidemiology of Pott's disease and its treatment success are unknown. The Stop TB Strategy and Consolidated Action Plan to Prevent and Combat M/XDR-TB provide comprehensive roadmaps to address all types of TB. CONCLUSIONS: There is a need to further analyze country data to document the extent of Pott's disease and develop specific guidelines for timely diagnosis and treatment of Pott's disease.
Asunto(s)
Salud Pública , Tuberculosis/epidemiología , Antituberculosos/uso terapéutico , Europa (Continente)/epidemiología , Humanos , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Organización Mundial de la SaludRESUMEN
BACKGROUND: Patients treated for Lyme borreliosis (LB) frequently report persistent symptoms. Little is known about risk factors and etiology. METHODS: In a prospective observational cohort study with a follow-up of one year, we assessed a range of microbiological, immunological, genetic, clinical, functional, epidemiological, psychosocial and cognitive-behavioral variables as determinants of persistent symptoms after treatment for LB. Between 2015 and 2018 we included 1135 physician-confirmed LB patients at initiation of antibiotic therapy, through clinical LB centers and online self-registration. Two reference cohorts of individuals without LB (n = 4000 and n = 2405) served as a control. Prediction analyses and association studies were used to identify determinants, as collected from online questionnaires (three-monthly) and laboratory tests (twice). FINDINGS: Main predictors of persistent symptoms were baseline poorer physical and social functioning, higher depression and anxiety scores, more negative illness perceptions, comorbidity, as well as fatigue, cognitive impairment, and pain in 295 patients with persistent symptoms. The primary prediction model correctly indicated persistent symptoms in 71.0% of predictions (AUC 0.79). In patients with symptoms at baseline, cognitive-behavioral responses to symptoms predicted symptom persistence. Of various microbiological, immunological and genetic factors, only lower IL-10 concentrations in ex vivo stimulation experiments were associated with persistent symptoms. Clinical LB characteristics did not contribute to the prediction of persistent symptoms. INTERPRETATION: Determinants of persistent symptoms after LB were mainly generic, including baseline functioning, symptoms and cognitive-behavioral responses. A potential role of host immune responses remains to be investigated. FUNDING: Netherlands Organisation for Health Research and Development (ZonMw); the Dutch Ministry of Health, Welfare and Sport (VWS).
Asunto(s)
Enfermedad de Lyme , Humanos , Estudios Prospectivos , Enfermedad de Lyme/diagnóstico , Enfermedad de Lyme/tratamiento farmacológico , Enfermedad de Lyme/epidemiología , Antibacterianos/uso terapéutico , Países Bajos , Encuestas y CuestionariosRESUMEN
To determine differences in the ability of Mycobacterium tuberculosis strains to withstand antituberculosis drug treatment, we compared the activity of antituberculosis drugs against susceptible Beijing and East-African/Indian genotype M. tuberculosis strains. Beijing genotype strains showed high rates of mutation within a wide range of drug concentrations, possibly explaining this genotype's association with multidrug-resistant tuberculosis.
Asunto(s)
Antituberculosos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Amicacina/farmacología , Compuestos Aza/farmacología , Proteínas Bacterianas/genética , Fluoroquinolonas , Genotipo , Isoniazida/farmacología , Pruebas de Sensibilidad Microbiana , Moxifloxacino , Mutación , Mycobacterium tuberculosis/genética , Quinolinas/farmacología , Rifampin/farmacología , Estadísticas no ParamétricasRESUMEN
Although variable-number tandem-repeat (VNTR) typing has gained recognition as the new standard for the DNA fingerprinting of Mycobacterium tuberculosis complex (MTBC) isolates, external quality control programs have not yet been developed. Therefore, we organized the first multicenter proficiency study on 24-locus VNTR typing. Sets of 30 DNAs of MTBC strains, including 10 duplicate DNA samples, were distributed among 37 participating laboratories in 30 different countries worldwide. Twenty-four laboratories used an in-house-adapted method with fragment sizing by gel electrophoresis or an automated DNA analyzer, nine laboratories used a commercially available kit, and four laboratories used other methods. The intra- and interlaboratory reproducibilities of VNTR typing varied from 0% to 100%, with averages of 72% and 60%, respectively. Twenty of the 37 laboratories failed to amplify particular VNTR loci; if these missing results were ignored, the number of laboratories with 100% interlaboratory reproducibility increased from 1 to 5. The average interlaboratory reproducibility of VNTR typing using a commercial kit was better (88%) than that of in-house-adapted methods using a DNA analyzer (70%) or gel electrophoresis (50%). Eleven laboratories using in-house-adapted manual typing or automated typing scored inter- and intralaboratory reproducibilities of 80% or higher, which suggests that these approaches can be used in a reliable way. In conclusion, this first multicenter study has documented the worldwide quality of VNTR typing of MTBC strains and highlights the importance of international quality control to improve genotyping in the future.
Asunto(s)
Técnicas de Tipificación Bacteriana/métodos , Técnicas de Tipificación Bacteriana/normas , Repeticiones de Minisatélite , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/genética , Automatización/métodos , Humanos , Control de Calidad , Reproducibilidad de los ResultadosRESUMEN
The development of a rapid test to identify Mycobacterium tuberculosis Beijing isolates and specifically strain GC1237, coming from a sub-Saharan country, is needed due to its alarming wide spread on Gran Canaria Island (Spain). A rapid test that detects IS6110 present between dnaA and dnaN in the Beijing strains and in a specific site for GC1237 (Rv2180c) has been developed. This test would be a useful tool in the surveillance of subsequent cases.
Asunto(s)
Técnicas Bacteriológicas/métodos , Técnicas de Diagnóstico Molecular/métodos , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis/diagnóstico , Elementos Transponibles de ADN , ADN Bacteriano/genética , Genes Bacterianos , Humanos , Mycobacterium tuberculosis/genética , EspañaRESUMEN
Tuberculosis patients may be infected with or have disease caused by more than one Mycobacterium tuberculosis strain, usually referred to as "mixed infections." These have mainly been observed in settings with a very high tuberculosis incidence and/or high HIV prevalence. We assessed the rate of mixed infections in a population-based study in rural Vietnam, where the prevalences of both HIV and tuberculosis are substantially lower than those in previous studies looking at mixed infections. In total, 1,248 M. tuberculosis isolates from the same number of patients were subjected to IS6110 restriction fragment length polymorphism (RFLP) typing, spoligotyping, and variable-number-tandem-repeat (VNTR) typing. We compared mixed infections identified by the presence of (i) discrepant RFLP and spoligotype patterns in isolates from the same patient and (ii) double alleles at ≥ 2 loci by VNTR typing and assessed epidemiological characteristics of these infections. RFLP/spoligotyping and VNTR typing identified 39 (3.1%) and 60 (4.8%) mixed infections, respectively (Cohen's kappa statistic, 0.57). The number of loci with double alleles in the VNTR pattern was strongly associated with the proportion of isolates with mixed infections according to RFLP/spoligotyping (P < 0.001). Mixed infections occurred more frequently in newly treated than in previously treated patients, were significantly associated with minor X-ray abnormalities, and were almost significantly associated with lower sputum smear grades. Although the infection pressure in our study area is lower than that in previously studied populations, mixed M. tuberculosis infections do occur in rural South Vietnam in at least 3.1% of cases.
Asunto(s)
Coinfección/epidemiología , Coinfección/microbiología , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis/epidemiología , Tuberculosis/microbiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Elementos Transponibles de ADN , ADN Bacteriano/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Repeticiones de Minisatélite , Tipificación Molecular , Polimorfismo de Longitud del Fragmento de Restricción , Prevalencia , Población Rural , Vietnam , Adulto JovenRESUMEN
A young female health professional was diagnosed with pulmonary tuberculosis caused by Mycobacterium bovis. Source finding and contact tracing was initiated by the regional municipal health service using both tuberculin skin test and QuantiFERON(®)-TB Gold (QFT-GIT (IGRA). The strain appeared near-identical to that of an elderly Dutch patient.
Asunto(s)
Transmisión de Enfermedad Infecciosa de Paciente a Profesional , Mycobacterium bovis/genética , Enfermeras y Enfermeros , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/transmisión , Animales , Bovinos , Trazado de Contacto , Elementos Transponibles de ADN/genética , Femenino , Humanos , Interferón gamma/metabolismo , Mycobacterium bovis/clasificación , Mycobacterium bovis/inmunología , Casas de Salud , Polimorfismo de Longitud del Fragmento de Restricción , Juego de Reactivos para Diagnóstico , Prueba de Tuberculina , Tuberculosis Pulmonar/microbiología , Adulto JovenRESUMEN
BACKGROUND: Tuberculosis (TB) transmission is associated with patient-related risk factors. However, DNA fingerprint analysis has provided anecdotal evidence suggesting a role for bacteriological factors. METHODS: To examine the importance of the bacteriological component in TB transmission, we investigated the number of tuberculin skin test-positive (TST induration, ≥ 10 mm) contacts and secondary cases observed in contact investigations around TB cases in relation to the size of the genotype cluster the patient belonged to at the time of diagnosis. We also compared the number of TST-positive contacts and secondary cases of patients with drug-resistant and drug-susceptible TB. RESULTS: Larger clusters were independently associated with an increased number of positive contacts. The mean number of positive contacts ranged from 3.8 for clusters of 2 cases, to 4.7 for clusters of 3-10 cases, to 6.0 for cases in clusters of >10 cases (mean increase in number of positive contacts for every extra case in the cluster, 0.21; 95% confidence interval, 0.09-0.26). The mean number of positive contacts was significantly lower among index cases with isoniazid-monoresistant TB (1.6) than among index cases with pan-susceptible TB (4.6; relative number, 0.45; 95% confidence interval, 0.22-0.92). CONCLUSION: These results suggest that spread of tuberculosis also depends on bacteriological factors.
Asunto(s)
Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidad , Tuberculosis/microbiología , Tuberculosis/transmisión , Adulto , Anciano , Anciano de 80 o más Años , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , Trazado de Contacto , Dermatoglifia del ADN , ADN Bacteriano/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tipificación Molecular , Mycobacterium tuberculosis/clasificación , Prueba de Tuberculina , Factores de Virulencia/genéticaRESUMEN
In this retrospective study, the performance of nine serological screening assays for Lyme borreliosis (LB) diagnostics was evaluated using a study population of LB cases and controls. Sera derived from 74 well-defined LB cases and 122 controls were included. The LB cases were diagnosed with erythema migrans (EM; n = 11), Lyme neuroborreliosis (LNB; n = 35), Lyme arthritis (LA; n = 20), or acrodermatitis chronica atrophicans (ACA; n = 8). Controls comprised 74 age- and gender-matched healthy individuals and 48 patients with other diseases with anticipated high rates of cross-reactivity. The assays under evaluation were selected based on a literature review and expected continued availability with CE marking under the new in vitro diagnostic regulation (European Union) 2017/746. The overall sensitivity (IgG and IgM results combined) among LB cases ranged between 54.5% (6 of 11) and 90.9% (10 of 11) for EM patients and between 97.1% (34 of 35) and 100% for patients with LNB, LA, and ACA. The positivity rate ranged between 8.1% (6 of 74) and 29.7% (22 of 74) among the healthy controls and between 22.9% (11 of 48) and 64.6% (31 of 48) among the cross-reactivity controls. The IgM results were more heterogeneous than the IgG and IgM/IgG results and did not contribute to the overall sensitivity but substantially increased the positivity rates among the controls. In conclusion, all evaluated Borrelia serological screening assays performed comparably with respect to early- and late-disseminated LB. The addition of an IgM assay to the screening of Borrelia-specific IgG antibodies had no added value for the diagnosis of Lyme borreliosis. IMPORTANCE Serology plays an important role in the diagnosis of Lyme borreliosis. Guidelines prescribe a two-tier testing algorithm in which a highly sensitive screening assay is used for screening and reactive sera are retested with an immunoblot to reduce false positivity rates. Recently, two commonly used screening assays were discontinued, including the very well-performing C6 Lyme enzyme-linked immunosorbent assay (ELISA) (Immunetics). This study provides an evaluation of the performance of nine different Borrelia serology screening assays, eight with expected future availably and the C6 Lyme ELISA, using a well-defined study panel of Lyme borreliosis patients, healthy population controls, and cross-reactivity controls. Evaluation data on multiple assays aid diagnostic laboratories in their choice for a reliable Borrelia serology screening assay to improve their diagnostic algorithm for Lyme borreliosis.