This study found FQ resistance in 3.3% of all clinical isolates of M. tuberculosis. FQ resistance was correlated with first-line drug resistance and prior anti-tuberculous treatment, suggesting the need for routine FQ susceptibility testing in patients with these characteristics.

An increasing number of clinical isolations of rapidly growing mycobacteria (RGM) at the National Taiwan University Hospital were noted from 1992 to 2001. Broth microdilution MICs of 15 antimicrobial agents were determined for 200 clinical isolates of RGM, including the Mycobacterium fortuitum group (69 isolates), M. chelonae (39 isolates), and M. abscessus (92 isolates). Our results showed that the resistance rates of these isolates to the currently available agents were remarkably high. Amikacin was active against nearly all RGM isolates. Clarithromycin was usually active against M. abscessus (79% susceptibility) and the M. fortuitum group (65% susceptibility). The majority of M. fortuitum group isolates were susceptible to ciprofloxacin (62%) and imipenem (61%). The susceptibilities to other conventional anti-RGM agents of these isolates were poor but differed markedly by species. The newer fluoroquinolones (levofloxacin, moxifloxacin, and gatifloxacin) and meropenem showed better in vitro activities against the M. fortuitum group isolates than against the other two species of RGM. Linezolid had fairly good activity against these RGM isolates, particularly against M. chelonae isolates (82% susceptible). Telithromycin had poor activity against these RGM isolates (the MICs at which 50% of the isolates tested are inhibited [MIC 50 s] were 32 to 64 g/ml, and the MIC 90 s were >64 g/ml). (1,10,11,14,15,21,29). These organisms cause a variety of disseminated or localized diseases, particularly pulmonary infections as well as primary skin and soft tissue infections (1,7,21,22). Pseudo-outbreaks of infection due to these organisms caused by contaminated medical equipment have been reported (30, 31). These organisms are resistant to the conventional antituberculous agents, and their susceptibilities to other antimycobacterial agents varied with different members of this group of mycobacteria (4-6, 17, 18, 22-25, 27, 32). Some investigators have reported that in vitro susceptibilities to several of these agents correlated with clinical response to therapy (18,20). Furthermore, some recent in vitro susceptibility studies have demonstrated activity of newly developed antimicrobials (linezolid, telithromycin, tigecycline, and newer fluoroquinolones) against these organisms (3,8,26,28,32).With the increasing clinical importance of RGM responsible for clinical infections at the National Taiwan University Hospital (NTUH) and with an effort to identify potentially useful agents to treat these infections (9, 14, 30), we investigated the in vitro susceptibilities of recent RGM isolates to 15 antimicrobial agents, including those developed recently. MATERIALS AND METHODS Bacterial isolates.From January 1997 to June 2002, a total of 200 nonduplicate isolates (only one isolate per patient) of RGM, including 69 isolates of the M. fortuitum group, 92 of M. abscessus, and 39 of M. chelonae, that were recovered from various clinical samples were collected for the study (Table 1). These organisms were stored in Mueller-Hinton broth (B...

Disseminated tuberculosis remains a diagnostic challenge because the presentations are nonspecific. In the current retrospective study we describe the clinical characteristics and outcome of disseminated tuberculosis. From January 1995 to December 2004, patients with culture-confirmed tuberculosis who fulfilled the criteria for disseminated tuberculosis were selected and their medical records reviewed. Their clinical isolates were genotyped. Of the 3058 patients with culture-confirmed tuberculosis, 164 (5.4%) had disseminated disease; 14.0% of patients had acquired immunodeficiency syndrome. The most common radiographic finding was miliary lung lesions (47.0%); 31.1% of patients died at the end of the study. Poor prognostic factors included hypoalbuminemia, hyperbilirubinemia, renal insufficiency, and delayed antituberculosis treatment. Clinical findings suggestive of disseminated tuberculosis were miliary lung lesions, serum ferritin >1000 microg/L, infiltrative liver disease, and adjusted calcium >2.6 mmol/L. Simultaneously performing mycobacterial culture and histopathologic examination of bone marrow biopsy was more sensitive and faster than just performing mycobacterial blood culture in diagnosing disseminated tuberculosis. Of the 64 preserved Mycobacterium tuberculosis isolates, 47 (73.4%) were clustered and 27 (42.2%) were Beijing family. Since prognosis was worse in patients with delayed treatment, a high index of suspicion is required, especially in those with clinical findings suggestive of disseminated tuberculosis.

The performance of a nested PCR-based assay (the RAPID BAP-MTB; AsiaGen, Taichung, Taiwan) and the BD ProbeTec ET (DTB) system (Becton Dickinson, Sparks, Md.) for detection of Mycobacterium tuberculosis was evaluated with 600 consecutive clinical samples. These samples, including 552 respiratory specimens and 48 nonrespiratory specimens, were collected from 333 patients treated at National Taiwan University Hospital from September to October 2003. The results of both assays were compared to the gold standard of combined culture results and clinical diagnosis. The overall sensitivity and specificity of the RAPID BAP-MTB assay for respiratory specimens were 66.7% and 97.2%, respectively, and for the DTB assay they were 56.7% and 95.3%, respectively. The positive and negative predictive values for the RAPID BAP-MTB were 74.1% and 96.0%, respectively, and for the DTB assay they were 59.6% and 94.7%, respectively. For smear-negative samples, the sensitivity of the RAPID BAP-MTB and DTB assays was 57.1% and 40.5%, respectively. The RAPID BAP-MTB assay produced 14 false-positive results in 14 samples, including one of the six samples yielding Mycobacterium abscessus, one of the six samples yielding Mycobacterium avium intracellulare, one sample from a patient with a history of pulmonary tuberculosis with complete treatment, and three samples from three patients with a previous diagnosis of tuberculosis who were under treatment at the time of specimen collection. Among the 48 nonrespiratory specimens, the RAPID BAP-MTB assay was positive in one biopsy sample from a patient with lumbar tuberculous spondylitis and one pus sample from a patient with tuberculous cervical lymphadenopathy. Our results showed that the RAPID BAP-MTB assay is better than the DTB assay for both respiratory specimens and nonrespiratory specimens. The overall time for processing this assay is only 5 h. In addition, its diagnostic accuracy in smear-negative samples is as high as in smear-positive samples.