RESUMEN
Genotyping of Mycobacterium tuberculosis isolates has been widely used to support investigations of outbreaks and as a tool for studying transmission dynamics and other aspects of tuberculosis epidemiology. Its applications to contact investigations are more limited. Targeted typing can be used to confirm or disprove suspected relationships among cases. Universal typing of isolates can be used to identify unsuspected transmission and broaden the scope of contact investigations. In order to properly use the results, one must understand the nature of the changes in the M. tuberculosis genome that produce the heterogeneity reflected in the genotypes, and understand the discriminatory power of the various methods. IS6110 fingerprinting provides the highest discriminatory power, but can be a slow process. Spoligotyping and MIRU-VNTR are PCR-based methods that provide faster turnaround and produce digital results that facilitate comparisons. Appropriately used, isolate genotyping can be a useful adjunct to standard contact investigations.
Asunto(s)
Centers for Disease Control and Prevention, U.S. , Trazado de Contacto/métodos , Mycobacterium tuberculosis/genética , Tuberculosis/microbiología , Tuberculosis/transmisión , Dermatoglifia del ADN , ADN Bacteriano/genética , Genotipo , Humanos , Estados UnidosRESUMEN
SETTING: An outbreak of tuberculosis caused by Mycobacterium tuberculosis resistant to isoniazid and streptomycin (HS-resistant) was documented in Boston's homeless population in 1984. Isolate relatedness was confirmed at the time by phage typing. In the late 1990s, cases of HS-resistant tuberculosis in the homeless were also documented, confirmed by RFLP typing using IS6110. None of the phage typed isolates from the 1980s were viable for performing RFLP analysis. We attempted to determine, using mixed-linker PCR (M-L PCR) finger-printing, whether or not these cases were all due to the same strain of M. tuberculosis. DESIGN: Isolates from 10 HS-resistant patients-four non-viable isolates from the 1980s and six viable isolates from 1996-1997-were sent to the Centers for Disease Control and Prevention for M-L PCR fingerprinting. These results were combined with record reviews of older cases and an ongoing epidemiologic investigation. RESULTS: Eight of 10 of the isolates were clonal, and the other two were strongly suspected matches. Epidemiologic investigation determined that transmission continued to occur after the initial outbreak in 1984-1985, and that a streptomycin-monoresistant variant of the strain was also circulating. CONCLUSION: M-L PCR fingerprinting combined with epidemiology was able to document links between cases across 15 years.
Asunto(s)
Células Clonales , Brotes de Enfermedades , Personas con Mala Vivienda/estadística & datos numéricos , Mycobacterium tuberculosis/genética , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/genética , Antibióticos Antituberculosos/uso terapéutico , Antituberculosos/uso terapéutico , Boston/epidemiología , Femenino , Humanos , Isoniazida/uso terapéutico , Masculino , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Estreptomicina/uso terapéutico , Factores de Tiempo , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológicoRESUMEN
Drug-susceptible and drug-resistant isolates of Mycobacterium tuberculosis were recovered from 2 patients, 1 with isoniazid-resistant tuberculosis (patient 1) and another with multidrug-resistant tuberculosis (patient 2). An investigation included patient interviews, record reviews, and genotyping of isolates. Both patients worked in a medical-waste processing plant. Transmission from waste was responsible for at least the multidrug-resistant infection. We found no evidence that specimens were switched or that cross-contamination of cultures occurred. For patient 1, susceptible and isoniazid-resistant isolates, collected 15 days apart, had 21 and 19 restriction fragments containing IS6110, 18 of which were common to both. For patient 2, a single isolate contained both drug-susceptible and multidrug-resistant colonies, demonstrating 10 and 11 different restriction fragments, respectively. These observations indicate that simultaneous infections with multiple strains of M. tuberculosis occur in immunocompetent hosts and may be responsible for conflicting drug-susceptibility results, though the circumstances of infections in these cases may have been unusual.
Asunto(s)
Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis Pulmonar/microbiología , Adulto , Antituberculosos/farmacología , Dermatoglifia del ADN , Resistencia a Múltiples Medicamentos , Femenino , Humanos , Isoniazida/farmacología , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/genética , Especificidad de la Especie , Esputo/microbiologíaRESUMEN
Spacer oligonucleotide typing (spoligotyping) is widely used for differentiation of bacteria of the Mycobacterium tuberculosis complex. However, the absence of any standardised method for concise description of spoligotypes makes it difficult to compare the results from different laboratories. This paper describes unambiguous, interconvertible systems for the designation of spoligotype patterns, the adoption of which will be beneficial to mycobacterial research.
Asunto(s)
Mycobacterium tuberculosis/clasificación , Terminología como Asunto , Bases de Datos Factuales , Humanos , Oligonucleótidos , SerotipificaciónRESUMEN
We have developed an amplification-based reverse dot blot assay for the detection of specific sites of insertion of the Mycobacterium tuberculosis insertion sequence IS6110. In this assay, a set of biotin-labeled amplicons representing the various copies of IS6110 and their flanking sequences is generated by linker-mediated PCR. The amplicons are then hybridized to immobilized oligonucleotide probes that are specific for known IS6110 insertion sites. The method was evaluated using an array of oligonucleotide probes corresponding to IS6110 insertion sites from M. tuberculosis strains CDC1551, Erdman, and H37Rv, and multidrug-resistant strain W. A set of 72 DNA samples from 60 M. tuberculosis clinical isolates was analyzed for the presence or absence of these insertion sites, and the assay was found to be highly reproducible. This method of identifying insertion sites has been named "insite" and can be used for the genotyping of M. tuberculosis complex strains based on IS6110 insertion site profiles.
Asunto(s)
Elementos Transponibles de ADN/genética , Mycobacterium tuberculosis/clasificación , Sondas de Oligonucleótidos/genética , Reacción en Cadena de la Polimerasa/métodos , Tuberculosis Pulmonar/microbiología , Técnicas de Tipificación Bacteriana , Amplificación de Genes , Genoma Bacteriano , Humanos , Mycobacterium tuberculosis/genética , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Mycobacterium bovis is naturally resistant to the antituberculosis drug pyrazinamide (PZA). To determine whether all Mycobacterium tuberculosis complex isolates demonstrating PZA monoresistance were truly M. bovis, we examined the phenotype and genotype of isolates reported as PZA monoresistant in five counties in California from January 1996 through June 1999. Isolates reported by local laboratories to be PZA monoresistant were sent to the state reference laboratory for repeat susceptibility testing using the BACTEC radiometric method and to the Centers for Disease Control and Prevention for pncA sequencing and PCR-restriction fragment length polymorphism (RFLP) analysis of the oxyR gene. Of 1,916 isolates, 14 were reported as PZA monoresistant and 11 were available for retesting. On repeat testing, 6 of the 11 isolates were identified as PZA-susceptible M. tuberculosis, 1 was identified as PZA-monoresistant M. bovis, and 1 was identified as M. bovis BCG. The three remaining isolates were identified as PZA-monoresistant M. tuberculosis. Sequencing of the pncA and oxyR genes genotypically confirmed the two M. bovis and the six susceptible M. tuberculosis species. Each of the three PZA-monoresistant M. tuberculosis isolates had different, previously unreported, pncA gene mutations: a 24-bp deletion in frame after codon 88, a base substitution at codon 104 (Ser104Cys), and a base substitution at codon 90 (Ile90Ser). This study demonstrates that PZA monoresistance is not an absolute marker of M. bovis species but may also occur in M. tuberculosis, associated with a number of different mutational events in the pncA gene. It is the first report of PZA-monoresistant M. tuberculosis in the United States.
Asunto(s)
Antituberculosos/farmacología , Proteínas de Unión al ADN , Farmacorresistencia Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , Polimorfismo de Longitud del Fragmento de Restricción , Pirazinamida/farmacología , Tuberculosis/microbiología , Amidohidrolasas/genética , Proteínas Bacterianas/genética , California , Centers for Disease Control and Prevention, U.S. , Genotipo , Humanos , Mycobacterium bovis/clasificación , Mycobacterium bovis/efectos de los fármacos , Mycobacterium bovis/genética , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/genética , Fenotipo , Reacción en Cadena de la Polimerasa/métodos , Proteínas Represoras/genética , Factores de Transcripción/genética , Estados UnidosRESUMEN
Resistance to rifampin in Mycobacterium tuberculosis results from mutations in the gene coding for the beta subunit of RNA polymerase (rpoB). At least 95% of rifampin-resistant isolates have mutations in rpoB, and the mutations are clustered in a small region. About 40 distinct point mutations and in-frame insertions and deletions in rpoB have been identified, but point mutations in two codons, those coding for Ser(531) and His(526), are seen in about 70% of rifampin-resistant clinical isolates, with Ser(531)-to-Leu (TCG-to-TGG) mutations being by far the most common. To explore this phenomenon, we isolated independent, spontaneous, rifampin-resistant mutant versions of well-characterized M. tuberculosis laboratory strain H37Rv by plating 100 separate cultures, derived from a single low-density inoculum, onto rifampin-containing medium. Rifampin-resistant mutants were obtained from 64 of these cultures. Although we anticipated that the various point mutations would occur with approximately equal frequencies, sequencing the rpoB gene from one colony per plate revealed that 39 (60.9%) were Ser(531) to Leu. We conclude that, for unknown reasons, the associated rpoB mutation occurs at a substantially higher rate than other rpoB mutations. This higher mutation rate may contribute to the high percentage of this mutation seen in clinical isolates.
Asunto(s)
Antibióticos Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Proteínas de Plantas/genética , Rifampin/farmacología , ARN Polimerasas Dirigidas por ADN , Farmacorresistencia Microbiana/genética , Humanos , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/aislamiento & purificación , Mutación PuntualRESUMEN
A previously uncharacterized, slowly growing, scotochromogenic Mycobacterium species was detected by HPLC analysis of the cell-wall-bound mycolic acids. The mycolic acid pattern standard was shown to be a late-eluting, contiguous peak cluster occurring at approximately 8-9 min. The mycolic acid pattern was noted to be most similar in number of peaks and range of elution to that reported previously for Mycobacterium asiaticum. However, the relative distribution of peaks within the elution range demonstrated a pattern with prominent peaks that started to emerge later than the characteristic M. asiaticum pattern. Standard biochemical identification test results were similar to those of the photochromogenic species M. asiaticum. Comparative 16S rRNA gene sequence analysis confirmed the genetic uniqueness of the strains and demonstrated the unclassified mycobacteria to be in a unique, intermediate position between slow and rapid growers in the phylogenetic tree of Mycobacterium. The name Mycobacterium kubicae sp. nov. is proposed for this taxon. The type strain is CDC 941078T (= ATCC 700732T = CIP 106428T).
Asunto(s)
Mycobacterium/clasificación , Mycobacterium/crecimiento & desarrollo , Pigmentos Biológicos/análisis , Secuencia de Bases , Cromatografía Líquida de Alta Presión , ADN Ribosómico/análisis , ADN Ribosómico/genética , Genes de ARNr , Datos de Secuencia Molecular , Mycobacterium/química , Mycobacterium/fisiología , Ácidos Micólicos/análisis , Filogenia , ARN Ribosómico 16S/genética , Alineación de Secuencia , Análisis de Secuencia de ADNRESUMEN
We examined the correlation of mutations in the pyrazinamidase (PZase) gene (pncA) with the pyrazinamide (PZA) resistance phenotype with 60 Mycobacterium tuberculosis isolates. PZase activity was determined by the method of Wayne (L. G. Wayne, Am. Rev. Respir. Dis. 109:147-151, 1974), and the entire pncA nucleotide sequence, including the 74 bp upstream of the start codon, was determined. PZA susceptibility testing was performed by the method of proportions on modified Middlebrook and Cohn 7H10 medium. The PZA MICs were > or =100 microg/ml for 37 isolates, 34 of which had alterations in the pncA gene. These mutations included missense substitutions for 24 isolates, nonsense substitutions for 3 isolates, frameshifts by deletion for 4 isolates, a three-codon insertion for 1 isolate, and putative regulatory mutations for 2 isolates. Among 21 isolates for which PZA MICs were <100 microg/ml, 3 had the same mutation (Thr47-->Ala) and 18 had the wild-type sequence. For the three Thr47-->Ala mutants PZA MICs were 12.5 microg/ml by the method of proportions on 7H10 agar; two of these were resistant to 100 microg of PZA per ml and the third was resistant to 800 microg of PZA per ml by the BACTEC method. In all, 30 different pncA mutations were found among the 37 pncA mutants. No PZase activity was detected in 35 of 37 strains that were resistant to > or =100 microg of PZA per ml or in 34 of 37 pncA mutants. Reduced PZase activity was found in the three mutants with the Thr47-->Ala mutation. This study demonstrates that mutations in the pncA gene may serve as a reliable indicator of resistance to > or =100 microg of PZA per ml.
Asunto(s)
Amidohidrolasas/genética , Mycobacterium tuberculosis/genética , Amidohidrolasas/metabolismo , Antituberculosos/farmacología , ADN Bacteriano/análisis , Farmacorresistencia Microbiana/genética , Humanos , Pruebas de Sensibilidad Microbiana , Mutación , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/enzimología , Mycobacterium tuberculosis/metabolismo , Fenotipo , Pirazinamida/farmacología , Análisis de Secuencia de ADNRESUMEN
We developed a scheme for the rapid identification of Mycobacterium species based upon PCR amplification of polymorphic genetic regions with fluorescent primers followed by restriction and analysis by fluorescence capillary electrophoresis. Mycobacterium species were identified by restriction enzyme analysis of a 439-bp segment of the 65-kDa heat shock protein gene (labeled [both strands] at the 5' end with 4,7,2',7'-tetrachloro-6-carboxyfluorescein) using HaeIII and BstEII and of a 475-bp hypervariable region of the 16S rRNA gene (labeled [both strands] at the 5' end with 6-carboxyfluorescein) using HaeIII and CfoI. Samples were analyzed on an automated fluorescence capillary electrophoresis instrument, and labeled fragments were sized by comparison with an internal standard. DNA templates were prepared with pure cultures of type strains. In all, we analyzed 180 strains, representing 22 Mycobacterium species, and obtained distinctive restriction fragment length polymorphism (RFLP) patterns for 19 species. Three members of the Mycobacterium tuberculosis complex had a common RFLP pattern. A computerized algorithm which eliminates subjectivity from pattern interpretation and which is capable of identifying the species within a sample was developed. The convenience and short preparatory time of this assay make it comparable to conventional methodologies such as high-performance liquid chromatography and hybridization assays for identification of mycobacteria.
Asunto(s)
Técnicas de Tipificación Bacteriana , Electroforesis Capilar/métodos , Mycobacterium/clasificación , Mycobacterium/genética , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo de Longitud del Fragmento de Restricción , Proteínas Bacterianas/genética , Secuencia de Bases , Chaperonina 60 , Chaperoninas/genética , Cartilla de ADN/genética , Estudios de Evaluación como Asunto , Humanos , Mycobacterium/aislamiento & purificación , Infecciones por Mycobacterium/diagnóstico , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Especificidad de la Especie , Espectrometría de Fluorescencia , Tuberculosis/diagnósticoRESUMEN
A new insertion element, IS1549, was identified serendipitously from Mycobacterium smegmatis LR222 during experiments using a vector designed to detect the excision of IS6110 from between the promoter region and open reading frame (ORF) of an aminoglycoside phosphotransferase gene. Six of the kanamycin-resistant isolates had a previously unidentified insertion element upstream of the ORF of the aph gene. The 1,634-bp sequence contained a single ORF of 504 amino acids with 85% G+C content in the third codon position. The putative protein sequence showed a distant relationship to the transposase of IS231, which is a member of the IS4 family of insertion elements. IS1549 contains 11-bp terminal inverted repeats and is characterized by the formation of unusually long and variable-length (71- to 246-bp) direct repeats of the target DNA during transposition. Southern blot analysis revealed that five copies of IS1549 are present in LR222, but not all M. smegmatis strains carry this element. Only strains with a 65-kDa antigen gene with a PCR-restriction fragment length polymorphism type identical to that of M. smegmatis 607 contain IS1549. None of 13 other species of Mycobacterium tested by PCR with two sets of primers specific for IS1549 were positive for the expected amplified product.
Asunto(s)
Elementos Transponibles de ADN , Micobacterias no Tuberculosas/genética , Secuencias Repetitivas de Ácidos Nucleicos , Secuencia de Aminoácidos , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , Composición de Base , Secuencia de Bases , Southern Blotting , Farmacorresistencia Microbiana , Genes Bacterianos , Kanamicina/farmacología , Kanamicina Quinasa/genética , Datos de Secuencia Molecular , Mutación , Micobacterias no Tuberculosas/clasificación , Micobacterias no Tuberculosas/efectos de los fármacos , Sistemas de Lectura Abierta , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
Nontuberculous mycobacterial lymphadenitis presents an increasing clinical problem in immunocompetent young children. A slowly growing, nonphotochromogenic mycobacterium was recovered twice (isolates 2553/91 and 2554/91) from the lymphatic tissue of a child with recurrent cervical lymphadenitis. It could be differentiated biochemically from described Mycobacterium species, although it most closely resembled Mycobacterium malmoense by thin-layer chromatography and high-performance liquid chromatography of mycolic acids. A striking characteristic of the isolate was its high degree of susceptibility to antituberculous drugs in vitro, including isoniazid. Direct determination of the 16S rRNA gene sequence revealed a unique sequence and positioned the strain phylogenetically on a branch separate from M. malmoense within a group of slowly growing mycobacteria that show a high degree of similarity to M. simiae at the 16S rRNA gene level. Despite 99.6% sequence identity with M. simiae at the 16S rRNA gene level, DNA-DNA hybridization studies (hydroxyapatite method) demonstrated DNA relatedness of less than 40%. We conclude that this organism is a new species for which we propose the name M. heidelbergense. A culture of the type strain, strain 2554/91, has been deposited in the American Type Culture Collection as strain ATCC 51253.
Asunto(s)
Linfadenitis/etiología , Linfadenitis/microbiología , Infecciones por Mycobacterium/etiología , Infecciones por Mycobacterium/microbiología , Mycobacterium/patogenicidad , Antituberculosos/farmacología , Secuencia de Bases , Niño , Preescolar , ADN Bacteriano/genética , ADN Ribosómico/genética , Farmacorresistencia Microbiana , Genes Bacterianos , Humanos , Isoniazida/farmacología , Datos de Secuencia Molecular , Mycobacterium/clasificación , Mycobacterium/genética , Cuello , Filogenia , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Especificidad de la EspecieRESUMEN
Large-restriction-fragment pattern comparison of Mycobacterium avium from 85 blood, stool, and respiratory specimens from 25 human immunodeficiency virus-infected San Francisco patients revealed 4 strains that infected multiple people (3 groups of 2 patients and 1 group of 3 patients). Most patients harbored a single M. avium strain, but 2 strains were recovered from 8 patients. The significance of recovering 2 strains is not clear, since the second strain was seldom recovered more than once. The strain recovered from blood was recovered from stool of 4 patients and respiratory secretions of 6 patients >4 weeks before detection of bacteremia, indicating that the intestinal and respiratory tracts are entry portals from which M. avium can disseminate. M. avium from 21 cities outside of California served as controls. Thus, a single M. avium strain can cause disseminated infection in multiple patients. This may represent infection from a common environmental source or person-to-person spread.
Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/microbiología , ADN Bacteriano/análisis , Complejo Mycobacterium avium/genética , Infección por Mycobacterium avium-intracellulare/genética , Infecciones Oportunistas Relacionadas con el SIDA/epidemiología , California/epidemiología , Heces/microbiología , Humanos , Epidemiología Molecular , Infección por Mycobacterium avium-intracellulare/sangre , Infección por Mycobacterium avium-intracellulare/epidemiología , Polimorfismo de Longitud del Fragmento de Restricción , San Francisco/epidemiología , Esputo/microbiologíaRESUMEN
A commercial line probe assay kit (Inno-LiPA Rif.TB) for rapid identification of mutations in the rpoB gene associated with rifampin resistance in Mycobacterium tuberculosis was evaluated with a collection of 51 rifampin-resistant strains. Nine distinct rpoB mutations were identified. Concordances with automated sequence results for five wild-type kit probes and four probes for specific mutations were 94.1 and 100%, respectively. Overall concordance of the line probe assay kit with phenotypic rifampin susceptibility testing results was 90.2%.
Asunto(s)
Antibióticos Antituberculosos/farmacología , ARN Polimerasas Dirigidas por ADN/genética , Farmacorresistencia Microbiana/genética , Mycobacterium tuberculosis/aislamiento & purificación , Rifampin/farmacología , Tuberculosis/microbiología , Humanos , Técnicas de Sonda Molecular , Mutación , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/genética , Ciudad de Nueva York/epidemiología , Tuberculosis/epidemiologíaRESUMEN
BACKGROUND: A 1991 survey showed high levels of drug resistance among tuberculosis patients in New York, NY. As a result, the tuberculosis control program was strengthened, including expanded use of directly observed therapy and improved infection control. METHODS: We collected isolates from every patient in New York City with a positive culture for Mycobacterium tuberculosis during April 1994; results were compared with those in the April 1991 survey. RESULTS: From 1991 to 1994, the number of patients decreased from 466 to 332 patients. The percentage with isolates resistant to 1 or more antituberculosis drugs decreased from 33% to 24% (P < .01); with isolates resistant to at least isoniazid decreased from 26% to 18% (P < .05); and with isolates resistant to both isoniazid and rifampin decreased from 19% to 13% (P < .05). The number of patients with isolates resistant to both isoniazid and rifampin decreased by more than 50%. Among never previously treated patients, the percentage with resistance to 1 or more drugs decreased from 22% in 1991 to 13% in 1994 (P < .05). The number of patients with consistently positive culture results for more than 4 months decreased from 130 to 44. A history of antituberculosis treatment was the strongest predictor of drug resistance (odds ratio = 3.1; P < .001). Human immunodeficiency virus infection was associated with drug resistance among patients who never had been treated for tuberculosis. CONCLUSIONS: Drug-resistant tuberculosis declined significantly in New York City from 1991 to 1994. Measures to control and prevent tuberculosis were associated with a 29% decrease in the proportion of drug resistance and a 52% decrease in the number of patients with multidrug-resistant tuberculosis.
Asunto(s)
Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/microbiología , Infecciones Oportunistas Relacionadas con el SIDA/epidemiología , Infecciones Oportunistas Relacionadas con el SIDA/microbiología , Adolescente , Adulto , Antibióticos Antituberculosos/farmacología , Farmacorresistencia Microbiana , Resistencia a Múltiples Medicamentos , Femenino , Humanos , Isoniazida/farmacología , Masculino , Persona de Mediana Edad , Ciudad de Nueva York/epidemiología , Oportunidad Relativa , Rifampin/farmacología , Factores de Riesgo , Insuficiencia del Tratamiento , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/mortalidadRESUMEN
Polyphasic taxonomic methods were employed to characterize a new species of slowly growing, nonpigmented mycobacteria. We propose the name Mycobacterium triplex sp. nov. for this new taxon. Conventional identification testing demonstrated a group of similar organisms that were geographically widespread in the United States. Commercially available nucleic-acid probes specific for the Mycobacterium avium complex were unreactive for these strains. High-performance liquid chromatography analysis of the mycolic acids revealed mycolate profiles that closely resembled Mycobacterium simiae. Comparative 16S rRNA sequence data confirmed the phylogenetic relationship of the strains with the slowly growing mycobacteria. Representative-type strains have been deposited in the American Type Culture Collection as strain ATCC 700071 [corrected].
Asunto(s)
Mycobacterium/clasificación , Mycobacterium/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Secuencia de Bases , Cartilla de ADN/genética , Humanos , Datos de Secuencia Molecular , Mycobacterium/genética , Infecciones por Mycobacterium/epidemiología , Infecciones por Mycobacterium/microbiología , Complejo Mycobacterium avium/clasificación , Filogenia , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie , Terminología como Asunto , Estados Unidos/epidemiologíaRESUMEN
OBJECTIVE: To investigate a multi-institutional outbreak of highly resistant tuberculosis and evaluate patient outcome. DESIGN: Epidemiologic investigation of every tuberculosis case reported in New York City. SETTING: Patients cared for at all public and nonpublic institutions from January 1, 1990, to August 1, 1993 (43 months). PATIENTS: We reviewed medical and public health records and conducted clinical, epidemiologic, drug susceptibility, and restriction fragment length polymorphism (RFLP) analyses. A case was defined as tuberculosis in a patient with an isolate resistant to isoniazid, rifampin, ethambutol hydrochloride, and streptomycin (and rifabutin, if sensitivity testing included it), and, if RFLP testing was done, a pattern identical to or closely related to strain W. MAIN OUTCOME MEASURES: Patient survival and the conversion of sputum cultures from positive to negative. RESULTS: Of the 357 patients who met the case definition, 267 had identical or nearly identical RFLP patterns; isolates from the other 90 patients were not available for RFLP testing. Among these 267 patients, 86% were human immunodeficiency virus (HIV)-infected, 7% were HIV-negative, and 7% had unknown HIV status. All-cause mortality was 83%. Epidemiologic linkages were identified for 70% of patients, of whom 96% likely had nosocomially acquired disease at 11 hospitals. Survival was prolonged among patients who received medications to which their isolate was susceptible, especially capreomycin sulfate, and among patients with a CD4+ T-lymphocyte count greater than 0.200 x 10(9)/L (200/microL). Treatment with isoniazid and a fluoroquinolone antibiotic was also independently associated with longer survival. CONCLUSIONS: This outbreak accounted for nearly one fourth of the cases of multidrug-resistant tuberculosis in the United States during a 43-month period. Most patients had nosocomially acquired disease, were infected with HIV, and unless promptly and appropriately treated, died rapidly. With appropriate directly observed treatment, especially combinations including an injectable medication, even severely immunocompromised patients had culture conversion and prolonged, tuberculosis-free survival.