RESUMEN
We used DNA fingerprinting to analyse tuberculosis (TB) epidemiology in immigrant patients living in two major northern Italian urban areas. The study population included 1999 TB patients (1500 Italian-born and 499 immigrants). Univariate and multivariate logistic regression models were used to identify risk factors related to clustering similar proportions of immigrant and Italian-born patients (46%) had infection with TB strains that belonged to genetic clusters. This supports the hypothesis that the disease in foreign patients is more likely to have arisen from reactivation of latent infection acquired in the country of origin than from recent transmission. Gender, age, human immunodeficiency virus infection and drug resistance were not significantly linked to TB clustering. Risk factors associated with strain clustering were country of origin (Somalia, adjusted OR (AOR) 3.19, p 0.017; Peru, AOR 2.86, p 0.014; and Senegal, AOR 2.60, p 0.045) and city of residence. Immigrant status in the larger urban area was an independent risk factor for infection with clustered TB, as reinforced by a subanalysis of the Senegalese group. In conclusion, variations in TB transmission were observed among immigrants from different countries and even within national groups, where living conditions have been found to exert a profound impact. These results emphasize the importance of improving social integration of immigrant subjects in order to limit risks of TB transmission in developed countries.
Asunto(s)
Emigrantes e Inmigrantes , Mycobacterium tuberculosis/clasificación , Mycobacterium tuberculosis/genética , Tuberculosis/epidemiología , Tuberculosis/transmisión , Adulto , Anciano , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , Dermatoglifia del ADN , Femenino , Humanos , Italia/epidemiología , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Mycobacterium tuberculosis/aislamiento & purificación , Polimorfismo de Longitud del Fragmento de Restricción , Factores de Riesgo , Tuberculosis/microbiología , Población UrbanaRESUMEN
BACKGROUND: Correct identification of individuals with latent tuberculosis infection (LTBI) is a crucial element of the elimination strategy, allowing their adequate treatment. In addition to tuberculin skin test (TST), the Quantiferon test (QFT, based on whole blood gamma-interferon release) had been recently proposed. Aim of the study is to compare this test to TST for identification of LTBI in a non-selected population, in order to verify their value in identifying truly infected individuals (entitled to receive preventive chemotherapy), and to exclude from treatment those having a positive TST for other reasons (e.g. after BCG vaccination). METHODS: 136 consecutive persons (78 males, mean age 34 +/- 9 years) referred to the clinic for TST were recruited (78 born in low--or middle--income countries). Based on their history, the cases were divided into 4 groups: 1) recently traced contacts of whom 18 TST negative and 28 TST positive; 2) 22 screening subjects, all TST negative; 3) BCG vaccinated subjects (14); and 4) 54 subjects already undergoing treatment of LTBI for exposure to TB. RESULTS: The overall agreement between TST and QFT was 72% (64% in TST positive and 88.4% in TST negative subjects). The proportion of TST positive/QFT negative BCG vaccinated individuals was 23.1%. The K coefficient was 0.474 in recently traced contacts, 0.366 in BCG vaccinated individuals and 0.451 overall. CONCLUSIONS: The study results suggest that agreement between TST and QFT is lower in TST positive than in negative subjects, being lower in individuals treated for LTBI. Quantiferon does not seem to have brought significant improvement in the diagnosis of LTBI.
Asunto(s)
Anticuerpos Antibacterianos/análisis , Interferón gamma/inmunología , Mycobacterium tuberculosis/inmunología , Prueba de Tuberculina/métodos , Tuberculosis/diagnóstico , Adulto , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Humanos , Interferón gamma/sangre , Masculino , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , Estudios Retrospectivos , Tuberculosis/sangreRESUMEN
Two commercial assays that detect Mycobacterium tuberculosis complex (MTB) in clinical specimens by rRNA target amplification (AMTDII) and ligase chain reaction (LCx) were evaluated. The tests were applied to 457 respiratory (n = 273) and extrapulmonary (n = 184) specimens collected from 357 patients. The results were compared with those of acid-fast staining and culture. The combination of culture and clinical diagnosis was considered to be the "gold standard." Seventy specimens were from patients with pulmonary tuberculosis and 28 specimens were from patients with extrapulmonary tuberculosis. After resolution of discrepant results, the overall sensitivities, specificities, and positive and negative predictive values for respiratory specimens were 92.8, 99.4, 98.5, and 97%, respectively, for AMTDII and 75.7, 98.8, 96.4, and 90.5%, respectively, for LCx. With extrapulmonary specimens, the overall sensitivities, specificities, and positive and negative predictive values were 78.6, 99.3, 95.6, and 96.2%, respectively, for AMTDII and 53.6, 99.3, 93.7, and 92.1%, respectively, for LCx. The level of agreement between AMTDII and LCx assay results was 78.2%. We conclude that although both nucleic acid amplification methods are rapid and specific for the detection of MTB in clinical specimens, AMTDII is significantly more sensitive than LCx with both respiratory (P = 0.005) and extrapulmonary (P = 0.048) specimens.
Asunto(s)
Mycobacterium tuberculosis/aislamiento & purificación , Bronquios/microbiología , Amplificación de Genes , Humanos , Mycobacterium tuberculosis/genética , ARN Ribosómico/genética , Sensibilidad y Especificidad , Esputo/microbiologíaRESUMEN
We describe the case of a patient with a chronic pulmonary infection due to a mycobacterium tentatively identified as Mycobacterium flavescens, but finally shown to be Mycobacterium szulgai; this is the first M. szulgai infection reported in Italy. The patient responded to treatment with multiple antituberculosis drugs only after two cycles of 10 and 6 months, respectively. The literature concerning previous case reports in which M. szulgai is involved is revised and the difficulty concerning the identification of this rare mycobacterium, along with its in vitro and in vivo susceptibility, are discussed.
Asunto(s)
Infecciones por Mycobacterium no Tuberculosas/microbiología , Tuberculosis Pulmonar/microbiología , Humanos , Masculino , Persona de Mediana Edad , Micobacterias no Tuberculosas/aislamiento & purificaciónRESUMEN
The use of high-performance liquid chromatography (HPLC) revealed four previously unreported profiles within a group of mycobacteria consisting of 14 clinical isolates. These mycobacteria, whose identification by conventional tests appeared problematic, mostly resembled Mycobacterium avium complex or Mycobacterium simiae. Genetic analysis revealed, within this group, six different nucleic acid sequences in a hypervariable 16S rRNA segment, but all the isolates appeared to be phylogenetically related to M. simiae. Six isolates representing the largest of groups defined by means of genetic sequencing turned out to belong to the newly described species Mycobacterium lentiflavum. Furthermore, three such clusters precisely coincided with three of those defined by HPLC, while the three remaining clusters shared almost identical HPLC profiles. All but one strain (which, although clearly not belonging to the M. avium complex, hybridized with specific commercial DNA probes) showed high-grade resistance to the majority of antimycobacterial drugs. Three of the isolates were clinically significant according to stringent criteria. Sophisticated techniques, like genetic sequencing or HPLC, by now seem indispensable for differentiating unusual and new mycobacteria from well-established ones.
Asunto(s)
Técnicas Bacteriológicas , Mycobacterium/clasificación , Mycobacterium/genética , Filogenia , Adulto , Anciano , Secuencia de Bases , Niño , Preescolar , Cromatografía Líquida de Alta Presión , ADN Bacteriano/genética , Femenino , Humanos , Lípidos/aislamiento & purificación , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Mycobacterium/aislamiento & purificación , Infecciones por Mycobacterium/diagnóstico , Infecciones por Mycobacterium/microbiología , Reacción en Cadena de la Polimerasa , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Homología de Secuencia de Ácido NucleicoRESUMEN
A mycobacterium isolated form a cultured snakehead with nodular lesions was identified on the basis of high performance liquid chromatography (HPLC) profile of cell wall mycolic acids, and confirmed by conventional tests, as Mycobacterium poriferae, a species previously isolated only from a marine sponge. The profiles of M. poriferae, Mycobacterium aurum and Mycobacterium parafortuitum are here reported for the first time.
Asunto(s)
Enfermedades de los Peces/microbiología , Mycobacterium/aislamiento & purificación , Tuberculosis/microbiología , Animales , Cromatografía Líquida de Alta Presión , Peces , Mycobacterium/química , Ácidos Micólicos/análisisRESUMEN
A case of mycobacterial lymphadenitis due to Mycobacterium malmoense was recently diagnosed in a 5-year-old girl. The organism was isolated from pus and tissue fragments obtained by surgical excision of the affected nodes. This is the first documented case of human infection due to this organism in Italy.
Asunto(s)
Linfadenitis/microbiología , Infecciones por Mycobacterium no Tuberculosas/microbiología , Micobacterias no Tuberculosas/aislamiento & purificación , Preescolar , Femenino , HumanosRESUMEN
Mycobacterium celatum is a recently described species which, on the basis of conventional tests, may be misidentified as Mycobacterium xenopi or as belonging to the Mycobacterium avium complex. Only genomic sequencing or high-performance liquid chromatography of cell wall mycolic acids can presently allow a correct identification of this mycobacterium. Two cases of infection due to M. celatum, in AIDS patients, are described here. The quantitative susceptibility pattern of the isolates to a wide spectrum of drugs is also reported.
Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/microbiología , Síndrome de Inmunodeficiencia Adquirida/microbiología , Infecciones por Mycobacterium/microbiología , Mycobacterium/aislamiento & purificación , Síndrome de Inmunodeficiencia Adquirida/complicaciones , Adulto , Técnicas de Tipificación Bacteriana , Femenino , Humanos , Huésped Inmunocomprometido , Masculino , Pruebas de Sensibilidad Microbiana , Mycobacterium/clasificación , Mycobacterium/efectos de los fármacos , Infecciones por Mycobacterium/complicaciones , Ácidos Micólicos/análisisRESUMEN
Previous studies revealed heterogeneous behavior within the species Mycobacterium kansasii against commercially available DNA probes (Accuprobe M. kansasii culture identification test; Gen-Probe); several isolates, conventionally identified as M. kansasii, failed in fact to hybridize. Looking for a possible association with phenotypic features, we tested a fully characterized panel of 69 clinical isolates of M. kansasii (19 of which were Accuprobe negative) with a semiquantitative micromethod which tests for 19 enzymatic activities (Api Zym; BioMérieux). The strains were from 25 hospitals in 18 Italian towns; 20 isolates came from human immunodeficiency virus type 1-positive patients who fulfilled the Centers for Disease Control criteria for AIDS diagnosis. On the basis of the whole set of phenotypic traits, our strains clustered in two groups, allowing the differentiation of biotypes within the species. There was a perfect association between biotype 2 and hybridization failures with Accuprobe and a very significant association between this novel biotype 2 and AIDS status, which suggests that it differs in virulence.
Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/microbiología , Seropositividad para VIH/complicaciones , Infecciones por Mycobacterium no Tuberculosas/microbiología , Micobacterias no Tuberculosas/clasificación , Análisis por Conglomerados , Sondas de ADN , Humanos , Infecciones por Mycobacterium no Tuberculosas/complicaciones , Micobacterias no Tuberculosas/enzimología , Fenotipo , Especificidad de la EspecieRESUMEN
A commercially available DNA probe (the AccuProbe Mycobacterium kansasii culture identification test, Gen-Probe, USA) for the identification of Mycobacterium kansasii was tested on a panel of 143 fully characterized mycobacterial strains. The isolates included 70 Mycobacterium kansasii and 73 mycobacteria other than kansasii. The specificity was 100% while the sensitivity was 72.8%. This sensitivity is unusually low in comparison with that of commercial DNA probes for other mycobacteria and confirms a previous study that found genetic heterogeneity within the species Mycobacterium kansasii. Strains that do not hybridize with the AccuProbe are particularly prevalent in Italy and perhaps elsewhere in Europe.
Asunto(s)
Sondas de ADN , Micobacterias no Tuberculosas/aislamiento & purificación , Sensibilidad y EspecificidadRESUMEN
The authors present 44 patients operated for hernias (inguinal and/or femoral) with a median pre-peritoneal approach positioning a mersilene mesh with Stoppa's technique. The results are very interesting considering that the hernias treated are all at high risk of recurrence. We had 4 complications (1 bleeding and 3 wound infections) that were conservatively treated, no mortality at all. The follow-up was of 12 months (mean) and no recurrence was discovered.
Asunto(s)
Hernia Femoral/cirugía , Hernia Inguinal/cirugía , Tereftalatos Polietilenos , Mallas Quirúrgicas , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Métodos , Persona de Mediana Edad , Peritoneo , Complicaciones Posoperatorias/epidemiología , RecurrenciaRESUMEN
A new biphasic system (MB Check, Roche) for isolation of mycobacteria from clinical specimens was evaluated by eight different microbiological laboratories in comparison with methods routinely used in the respective laboratories. Altogether 1125 clinical specimens were processed; pretreatment, if performed, was by a variety of methods. Mycobacteria were recovered from 167 specimens with the biphasic system and 165 specimens with the other methods. The average time required for isolation of Mycobacterium tuberculosis was 22.6 days with the biphasic system and 24.7 days with egg-based media; for other mycobacterial species it was 23.5 versus 20.8 days. The inclusion of a chocolate agar section in the biphasic system facilitated the early detection of contaminants, while the NAP-containing section appeared unable to differentiate Mycobacterium tuberculosis from other mycobacterial species. The biphasic system, which enables recovery of mycobacteria in small laboratories without specialized equipment, is more practical than conventional methods and at least as sensitive.
Asunto(s)
Técnicas Bacteriológicas , Infecciones por Mycobacterium/microbiología , Mycobacterium/aislamiento & purificación , Derrame Pleural/microbiología , Esputo/microbiología , Líquido del Lavado Bronquioalveolar/microbiología , Humanos , Infecciones por Mycobacterium/sangre , Infecciones por Mycobacterium/orina , Mycobacterium tuberculosis/aislamiento & purificación , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
A case of gastrointestinal bleeding in an 83 y.o. white female is reported. The source of bleeding was from a solitary jejunal diverticulum. The Authors discuss the clinical findings, the pathogenetic hypothesis, the diagnostic approach and the surgical therapy.
Asunto(s)
Divertículo/complicaciones , Hemorragia Gastrointestinal/etiología , Enfermedades del Yeyuno/complicaciones , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Divertículo/diagnóstico , Divertículo/cirugía , Femenino , Hemorragia Gastrointestinal/cirugía , Humanos , Enfermedades del Yeyuno/diagnóstico , Enfermedades del Yeyuno/cirugíaAsunto(s)
Gangrena , Escroto , Anciano , Ampicilina/administración & dosificación , Clindamicina/administración & dosificación , Diverticulitis del Colon/complicaciones , Quimioterapia Combinada , Gangrena/etiología , Gangrena/cirugía , Enfermedades de los Genitales Masculinos/etiología , Enfermedades de los Genitales Masculinos/cirugía , Gentamicinas/administración & dosificación , Humanos , Masculino , Escroto/cirugía , Enfermedades del Sigmoide/complicaciones , SíndromeRESUMEN
We have tested in the IUTM egg medium the susceptibility against amikacin (AKC) of 147 strains of Mycobacterium tuberculosis (M.t.) isolated from the sputum of patients affected with pulmonary Tb. Only five strains showed resistance at 5 and 10 mcg/ml: they were also resistant to other main anti-tubercular drugs (MATD). The other 59 strains resistant to MATD and the 82 ones without any resistance to MATD were found normally susceptible to AKC at 5 mcg/ml in IUTM m. The parallel test performed on a synthetic medium (7H10) with 10 firstly-observed strains, allowed us to define that AKC undergoes a 60% inactivation in the egg medium. Two patients suffering from chronic pulmonary Tb, with M.t. constantly isolable in their sputum, assumed a twice-weekly treatment (TWT) with AKC alone (total 26 gr). This management induced in them improvement of the radiological and bacteriological findings, without alteration of the checking parameters.