RESUMO
We evaluated the BACTEC MGIT 960 system, which is a fully automated, non-invasive, continuous monitoring system for the growth and detection of mycobacteria. Including respiratory and other specimens, 1,742 specimens were processed and inoculated into the BACTEC MGIT 960 and the BACTEC 460 TB Systems, as well as onto Lowenstein-Jensen (L-J) media. A total of 104 isolates of mycobacteria were recovered from all culture systems. This included Mycobacterium tuberculosis complex, Mycobacterium avium-intracellulare (MAI) complex and other mycobacteria (MOTT). The isolation rates for M. tuberculosis complex and MAI complex were comparable for the BACTEC 460 (54.8% and 13.5%) and the BACTEC MGIT 960 (51.9% and 13.5%). The overall isolation rate was less for BACTEC MGIT 960 (76.9%) which was due to lesser number of MOTT isolates recovered from this system. The mean times to detection (TTD) for all mycobacteria were 9.3 days for the BACTEC MGIT, 14.6 days for the BACTEC 460 and 21.6 days for L-J. A significant difference was observed when TTD was tested in relation to degree of positivity in smears, with the BACTEC MGIT maintaining the short TTD even with less number of bacilli in the smear. The contamination rates were, 6.4% for BACTEC MGIT, 2.9% for BACTEC 460 and 12.1% for L-J medium. The BACTEC MGIT 960 system shows performances comparable to the BACTEC 460 and seems to be a dependable, user friendly system.
Assuntos
Infecções por Mycobacterium/microbiologia , Mycobacterium/isolamento & purificação , Meios de Cultura , Estudos de Avaliação como Assunto , Humanos , Técnicas Microbiológicas , Mycobacterium/crescimento & desenvolvimento , Infecções por Mycobacterium/diagnóstico , Complexo Mycobacterium avium/crescimento & desenvolvimento , Complexo Mycobacterium avium/isolamento & purificação , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/isolamento & purificação , Hidróxido de Sódio , Fatores de TempoRESUMO
A 7-year-old girl had a 4 X 3 X 3 cm nodule on the left wrist with axillary lymphadenopathy. Acid-fast bacilli were seen on a smear from a biopsy specimen of this granulomatous skin lesion. A Rhodococcus species grew on culture. Skin infections caused by Rhodococcus may be more common than the few prior case reports suggest.
Assuntos
Infecções por Actinomycetales/patologia , Linfadenite/etiologia , Rhodococcus , Dermatopatias Infecciosas/patologia , Infecções por Actinomycetales/complicações , Infecções por Actinomycetales/diagnóstico , Criança , Feminino , Humanos , Pele/patologia , Dermatopatias Infecciosas/diagnóstico , Dermatopatias Infecciosas/etiologiaRESUMO
Three cases of mycobacterial infection were confirmed in our laboratory by exclusive isolation of the pathogen in Middlebrook 7H9 broth medium. The mycobacteria failed to grow in all three cases on three different solid media. In one patient Mycobacterium tuberculosis was isolated from a pleural biopsy; a lymph node biopsy from another patient also yielded M. tuberculosis and M. avium-intracellulare was isolated from the spinal fluid of a patient with acquired immunodeficiency syndrome (AIDS). Only the broth culture was positive in all three cases. We suggest these findings emphasise the need for laboratories to use a liquid medium in addition to egg-based or agar media, especially for isolation of mycobacteria from specimens with small numbers of bacilli.
