RESUMEN
The role of the species Mycobacterium haemophilum as a pathogenic non-tuberculous microorganism is becoming better defined with the use of specific detection methods. However, epidemiological investigations of this species are still scarce. We analysed the genetic diversity of M. haemophilum by amplified fragment length polymorphism (AFLP) typing and compared isolates from different parts of the world. In total, 128 isolates, including 41 from the USA, 51 from Australia, 28 from Europe and eight from Israel were compared using AFLP methodology. Two restriction enzymes (MseI and EcoRI) and one selective primer were applied and provided a high discriminatory power. Clusters of isolates with identical AFLP patterns, which could indicate a possible common source, were observed from the Netherlands, New York and Australia. No clear clustering on the basis of continental origin was observed; however, types were restricted to geographical areas and not found on other continents. A high genetic stability within the species was demonstrated by the long-term existence of a single type.
Asunto(s)
Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Infecciones por Mycobacterium/epidemiología , Infecciones por Mycobacterium/microbiología , Mycobacterium haemophilum/clasificación , Mycobacterium haemophilum/genética , Adulto , Australia/epidemiología , Técnicas de Tipificación Bacteriana , Niño , Preescolar , Análisis por Conglomerados , Dermatoglifia del ADN , Europa (Continente)/epidemiología , Femenino , Variación Genética , Genotipo , Humanos , Israel/epidemiología , Masculino , Epidemiología Molecular , Mycobacterium haemophilum/aislamiento & purificación , Estados Unidos/epidemiología , Adulto JovenRESUMEN
OBJECTIVE: To study the presence of bacterial factors in clinical isolates of Acinetobacter species in order to identify markers of epidemic potential. DESIGN: Case-control study. METHODS: Forty-six isolates of Acinetobacter species, including 23 epidemic and 23 sporadic strains from different outbreaks in nine European countries, were compared for the presence of the following factors: hemagglutination, presence of capsules and fimbriae, binding to salivary mucins, resistance to drying, and antibiogram typing. Genotyping of all strains was performed by amplified fragment-length polymorphism (AFLP). RESULTS: All outbreak strains except two (91%) were identified as Acinetobacter baumannii. Binding to salivary mucins and resistance to antibiotics were significantly associated with epidemic behavior. Antibiogram typing showed clustering of predominantly A baumannii strains within one group, and these strains were significantly more resistant to antibiotics than sporadic strains. AFLP genotyping revealed a great heterogeneity among the different European Acinetobacter strains. Cluster analysis of AFLP fingerprints showed several small clusters of different A baumannii outbreak strains. AFLP genotyping could not identify a common epidemic marker within the strains studied. CONCLUSIONS: Antibiogram typing can be used in routine clinical laboratories as a screening method to recognize potentially epidemic A baumannii strains. Several other factors were found, both in different outbreaks as well as in sporadic Acinetobacter isolates. These characteristics were unable to predict epidemic behavior and therefore cannot be used as discriminative epidemic markers. AFLP genotyping demonstrated no common clonal origin of European epidemic A baumannii strains. This indicates that any clinical A baumannii isolate with resistance to multiple antibiotics can be a potential nosocomial outbreak strain.
Asunto(s)
Infecciones por Acinetobacter/epidemiología , Acinetobacter/clasificación , Acinetobacter/efectos de los fármacos , Acinetobacter/genética , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/microbiología , Técnicas de Tipificación Bacteriana , Estudios de Casos y Controles , Farmacorresistencia Microbiana , Genotipo , Humanos , Modelos Logísticos , Pruebas de Sensibilidad Microbiana , Factores de RiesgoRESUMEN
Forty-eight clinical Acinetobacter isolates with different epidemic behavior were investigated for the presence of integrons and plasmids and for antibiotic susceptibility. Integrons were demonstrated in 50% of the strains by an integrase gene PCR. Epidemic strains of Acinetobacter baumannii were found to contain significantly more integrons than nonepidemic strains. Also, the presence of integrons was significantly correlated with simultaneous resistance to several antibiotics. Plasmids were detected in 42% of the strains. However, there was no significant correlation between the numbers of plasmids and integrons in Acinetobacter species strains, no significant difference in the number of plasmids between epidemic and nonepidemic A. baumannii strains, and no significant correlation between the presence of plasmids and antibiotic resistance. Hence, it is likely that integrons play an important role in antibiotic resistance and thereby in the epidemic behavior of A. baumannii. Because the integrase gene PCR identified almost three-quarters of the epidemic A. baumannii isolates (17 of 23), this seems to be a rapid and simple technique for the routine screening and identification of clinical A. baumannii isolates with epidemic potential.
Asunto(s)
Infecciones por Acinetobacter/microbiología , Acinetobacter/clasificación , Brotes de Enfermedades , Integrasas/genética , Reacción en Cadena de la Polimerasa/métodos , Acinetobacter/efectos de los fármacos , Acinetobacter/genética , Infecciones por Acinetobacter/epidemiología , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Secuencia de Bases , Farmacorresistencia Microbiana/genética , Humanos , Pruebas de Sensibilidad Microbiana , Plásmidos/genéticaRESUMEN
The presence of Helicobacter pylori in the oral cavity (6 sites), oesophagus, stomach and bowel of 20 dyspeptic patients was investigated. Samples were cultured on three selective media and analyzed by 16S rDNA polymerase chain reaction (PCR) and southern hybridization. Helicobacter pylori DNA was detected by PCR from oral-cavity samples of three (20%) and from faeces samples of only one (7%) of the patients whose stomach biopsies were positive for Helicobacter pylori. When culture was used, the microorganism's rate of recovery from the oral cavity and faeces was 13% and 7%, respectively. One patient had a Helicobacter pylori-like organism in samples collected from the tongue and palate. Both strains were urease, catalase and oxidase positive and grew microaerophilically but were negative on PCR analysis. This demonstrates the possibility of false identification of Helicobacter pylori by use of routine enzyme reactions. Interestingly, specimens collected from the cheeks of three patients were positive for Helicobacter pylori by PCR analysis. This is the first instance of detection of this microorganism in the cheek.
Asunto(s)
Gastritis/diagnóstico , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/aislamiento & purificación , Adulto , Anciano , Endoscopía del Sistema Digestivo , Esófago/microbiología , Heces/microbiología , Femenino , Gastritis/etiología , Humanos , Masculino , Persona de Mediana Edad , Boca/microbiología , Reacción en Cadena de la Polimerasa , Estómago/microbiologíaRESUMEN
The role of neuraminidase in haemagglutination and adherence to colon WiDr cells by eight strains of Bacteroides fragilis and four strains of oral black-pigmented gram-negative anaerobes was studied. Neuraminidase treatment resulted in a very small increase of haemagglutination by some of the strains but had no effect on adherence to WiDr cells by all bacterial strains tested except one strain of Prevotella intermedia (HG 110). Inhibition of neuraminidase had no effect on haemagglutination or adherence, nor was any correlation found between haemagglutinating ability and neuraminidase activity in the B. fragilis strain. The results indicated that haemagglutination and adherence of B. fragilis to WiDr cells were not mediated by neuraminidase.