Outbreak of cryptosporidiosis in a child day-care centre in Gipuzkoa, Spain, October to December 2011.

From October to December 2011, an outbreak of 26 cases of cryptosporidiosis occurred in a day-care centre in Gipuzkoa, Spain. The infection spread from person to person and affected 24 children under two years of age (attack rate: 38%) and two caregivers. Cryptosporidium oocysts were observed in 10 of 15 samples. During 2010, only four cases of cryptosporidium were detected in Gipuzkoa, and 27 overall in Spain.

Evaluation of two different cell lysis methods for releasing mycobacterial nucleic acids in the INNO-LiPA mycobacteria test.

The INNO-LiPA Mycobacteria Test (Innogenetics, N.V., Belgium) is a PCR-based reverse hybridization assay for the simultaneous identification of several mycobacterial species. We evaluated two simplified lysis methods for mycobacterial DNA release for application in the INNO-LiPA Mycobacteria Test. The two methods were based on either (i) heat treatment or (ii) sonication. Both methods were performed directly on 45 positive liquid cultures (MB-BacT, BioMérieux, Marcy l'Etoile, France) containing 17 different mycobacterial species. These two simple lysis procedures demonstrated similar effectiveness (100%) to that recommended by the manufacturer. They also significantly shortened the time required for mycobacterial DNA release.

Comparison of the sodium dodecyl sulfate-sodium hydroxide specimen processing method with the C18-carboxypropylbetaine specimen processing method using the MB/BacT liquid culture system.

The ability of physicians to diagnose tuberculosis is impacted by the use of smear and culture techniques combined with specimen processing methods. The objective of this study was to evaluate the effects of specimen processing on smear and culture sensitivity by comparing the specimen processing method that uses C(18)-carboxypropylbetaine with the method that combines sodium dodecyl sulfate and sodium hydroxide. A total of 1,201 specimens were entered into this study. Specimens were split approximately equally such that one-half of each specimen was processed with sodium dodecyl sulfate-sodium hydroxide, while the other half was processed with C(18)-carboxypropylbetaine. All sediments were subjected to acid-fast staining and then analyzed using the MB/BacT liquid culture system (bioMérieux, France) and solid media. The sensitivity of smear following processing with sodium dodecyl sulfate-sodium hydroxide and C(18)-carboxypropylbetaine was 61.2% and 58.6% (P>0.05), respectively, while the specificities were identical (99.7%). The sensitivity of culture was 84.2% and 96.1% (P<0.05), respectively. The time to detection in the MB/BacT liquid culture system was 13.2+/-5.6 and 15.0+/-8.8 days (P>0.05), respectively, and 20.0+/-7.6 and 15.7+/-8.9 days (P<0.05), respectively, on solid media. The contamination rates in the MB/BacT system were 0.8% and 8.7%, respectively, whereas the contamination rates on solid media were 2.6% and 4.3%, respectively. C(18)-carboxypropylbetaine specimen processing was less labor-intensive than sodium dodecyl sulfate-sodium hydroxide processing and improved the ability of laboratory staff to detect the presence of mycobacteria by culture.

Rapid detection of several mycobacterial species using a polymerase chain reaction reverse hybridisation assay.

The ability of a polymerase-chain-reaction-based technique combined with a reverse hybridisation line-probe assay to detect and identify eight of the most clinically significant mycobacterial species directly from cultures in liquid medium was evaluated. The line-probe assay allows simultaneous identification of eight different mycobacterial species. Ninety-seven mycobacterial strains belonging to 22 different species were evaluated. All strains were previously inoculated into MB/BacT bottles (Organon Teknika, USA). The sensitivity and specificity of the test when applied on positive MB/BacT liquid cultures containing isolates from mycobacterial species included as specific probes on the line-probe assay strip was 100% and 100%, respectively. These results further support the potential clinical usefulness of this technique in the diagnosis of mycobacterial infections.

Detection of mycobacterium tuberculosis in paraffin-embedded pleural biopsy specimens by commercial ribosomal RNA and DNA amplification kits.

STUDY OBJECTIVES: To evaluate the utility of two gene amplification systems in historical paraffin-embedded pleural biopsy (PEB) tissues from patients with pleural tuberculosis, and to compare the results to those obtained with conventional histologic and microbiological methods. DESIGN: A retrospective study. PATIENTS AND METHODS: Seventy-four formalin-fixed PEB tissues collected and stored over 12 years (1984 through 1995) were retrieved. Gene amplifications were performed in 57 tissues from patients with diagnoses of pleural tuberculosis and in 17 from patients with carcinoma as controls, using the first version of the Amplified Mycobacterium tuberculosis Direct Test (AMTDT; Gen-Probe; San Diego, CA) and the LCx Mycobacterium tuberculosis Assay (LCxMTB; Abbott Laboratories; Abbott Park, IL). RESULTS: The sensitivities of the AMTDT and LCxMTB were 52.6% and 63.2%, respectively (p = not statistically significant). The specificity of both tests was 100%. Twenty tissue samples (35.1%) were positive by both systems, and 10 tissues (17.5%) were positive only by the AMTDT, while 16 tissues (28.1%) were positive only by the LCxMTB. Both tests gave negative results for 11 specimens (19.3%). When both tests were used, a positive diagnosis was achieved in 80.7% of the samples. Diagnosis of 73.7% of patient conditions had previously been made by smear examination of pleural biopsy and sputum, pleural liquid, or biopsy culture. The overall diagnostic yield with both culture and amplification techniques was 96.5% (55 of 57 patients) for pleural tuberculosis, with amplification techniques adding 22.8% of the diagnoses. CONCLUSIONS: Amplification techniques are useful in archival PEB tissues, providing additional diagnoses beyond culturing, although the sensitivity should be improved, possibly by standardizing protocols.

Evaluation of a fluorescence hybridisation assay using peptide nucleic acid probes for identification and differentiation of tuberculous and non-tuberculous mycobacteria in liquid cultures.

The performance was evaluated of a fluorescence in situ hybridisation assay using peptide nucleic acid probes (Dako Probe MTB Culture Confirmation Test; Dako, Denmark) for identification of Mycobacterium tuberculosis complex (MTC) organisms and differentiation between tuberculous and non-tuberculous mycobacteria (NTM) in material taken directly from Bactec 12B (Becton Dickinson, USA) and MB/BacT (Organon Teknika, USA) bottles. The test was applied to 129 smear-positive (Ziehl-Neelsen stain) clinical specimens, 48 previously identified clinical strains of mycobacteria (12 MTC and 36 NTM), and 51 reference strains (7 MTC and 44 NTM) which were all previously inoculated into Bactec 12B and MB/BacT bottles. The sensitivity and specificity of the assay for MTC-positive cultures was 87.6% and 100%, respectively, for Bactec 12B, and 100%, respectively, for MB/BacT. The sensitivity and specificity of the assay for NTM-positive cultures was 100% for both media.

Serovars of Mycobacterium avium complex isolated from AIDS and non-AIDS patients in Spain.

Antigen fingerprinting based on surface glycolipid antigens was applied to the epidemiology of clinical isolates of the Mycobacterium avium complex from 128 acquired immunodeficiency syndrome (AIDS) and 31 non-AIDS patients from several different regions of Spain. The application of thin-layer chromatography, gas chromatography-mass spectrometry and monoclonal antibodies, combined with ELISA, allowed a facile identification, differentiation and classification of the isolates. The cumulative results demonstrate that, among the clinical isolates, serovar 4 was predominant in both AIDS (33.6%) and non-AIDS (22.6%) isolates. In general, the results demonstrate geographical as well as disease-related differences in the distribution of Myco. avium complex serovars of clinical importance.

[Drug resistance in Mycobacterium tuberculosis. A multicenter study of the Barcelona area. Grupo de Trabajo sobre Resistencias en Tuberculosis]. / Farmacorresistencia de Mycobacterium tuberculosis. Estudio multicéntrico en el area de Barcelona. Grupo de Trabajo sobre Resistencias en Tuberculosis.

BACKGROUND: The aims of this multicenter study was to establish the level of primary and acquired drug resistance of M. Tuberculosis strains isolated in Barcelona and to identify possible risk groups using clinical data. PATIENTS AND METHODS: All tuberculosis patients with isolation and identification of M. tuberculosis strains from October 1995 to September 1997 were included. Susceptibility tests isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide were performed using the Bactec 460 system and the proportions method on solid medium. Logistic progression was used for statistical analysis. RESULTS: The total number of patients included was 1,749 (1,535 non-treated and 214 previously treated). Primary drug resistance was 5.7% (isoniazid 3.8%; rifampin 1.0%, streptomycin 2.1%, ethambutol 0.3% and pyrazinamide 1.0%). Acquired drug resistance was 20.5% (isoniazid 17.3%, rifampin 9.8%, ethambutol 1.9%, streptomycin 4.7% and pyrazinamide 6.5%). Primary drug resistance was associated with people over 60 years old and women. CONCLUSIONS: The low level of drug resistance enables antituberculosis treatment of non-treated patients to start with the standardised three-drug regimes except in the case of foreign people from countries with a high level of drug resistance. Susceptibility tests are recommended on all M. tuberculosis strains isolated, together with controlled studies of drug resistance surveillance.

[The usefulness of the bone marrow examination in the etiological diagnosis of prolonged fever in patients with HIV infection]. / Utilidad del examen de la médula ósea en el diagnóstico etiológico de la fiebre prolongada en los pacientes con infección por el virus de la inmunodeficiencia humana.

BACKGROUND: To analyze the usefulness of bone marrow (BM) study in the diagnosis of fever of unknown origin (FUO) in patients infected by the human immunodeficiency virus (HIV) in a single center during a period of 42 months. PATIENTS AND METHODS: 182 episodes of FUO in 162 patients p3th HIV infection were studied. Age, sex, risk factor for HIV infection, hemoglobin level, counts of leucocytes, neutrophils, lymphocytes, CD4 positive lymphocytes, platelets and levels of hepatic enzymes, albumin and beta 2-microglobulin were studied. BM aspirate was performed in all episodes for cytologic and microbiologic examination, and BM biopsy was done in 43. Analysis of factors related with the probability of diagnosis by BM examination was carried out. RESULTS: The median age was 33 years (range, 22-70), and 123 were males. Drug abuse was the most frequent risk factor for HIV infection (63%). One hundred thirty patients had previous AIDS diagnosis before they were evaluated for unexplained fever. A specific diagnosis was achieved in 161 episodes (88%) and the most frequent diagnoses were Mycobacterium spp. (55%) and Leishmania spp. (14%) infections. Fifty-four episodes (30%) were diagnosed by BM examination, and in 36 (20%) BM study was the only diagnostic tool. Examination of the BM aspirate yielded the diagnosis in 40 out of the 178 episodes (13%), whereas BM biopsy was a diagnostic tool in 8 (19%); in 9 additional cases (21%) granulomas were observed. Microbiologic study of BM smears for mycobacterial infections was positive in 28 of the 143 episodes (19%), and the culture for Leishmania was positive in 2 out of the 42 cases. The presence of thrombocytopenia (< 75 x 10(9)/l) and elevated serum levels of aspartate-aminotransferase (AST) (> 100 U/l) were the factors associated with a high probability to obtain the diagnosis through BM study. CONCLUSIONS: In patients infected by the HIV and unexplained fever, BM examination is an useful procedure for the diagnosis, particularly in areas where infections by Mycobacterium spp. and Leishmania are prevalent. So that, in our setting, systematic use of this procedure is justified for diagnosis of FUO in those patients.

Prospective study of community-acquired pneumonia of bacterial etiology in adults.

The aim of this study was to prospectively analyze the bacterial etiology of community-acquired pneumonia in adults in Spain. From May 1994 to February 1996, 392 episodes of CAP diagnosed in the emergency department of a 600-bed university hospital were studied. An etiological diagnosis based on noninvasive microbiological investigations was achieved in 228 cases (58%); 173 of these diagnoses were definitive and 55 probable. Streptococcus pneumoniae, which caused 23.9% of the episodes, was the predominant pathogen observed, followed by Chlamydia pneumoniae (13.5%) and Legionella pneumophila (12.5%). Other less frequent pathogens found were Haemophilus influenzae (2.3%), Pseudomonas aeruginosa (1.5%), Mycoplasma pneumoniae (1.3%), Coxiella burnetii (1%), Moraxella catarrhalis (2 cases), Nocardia spp. (2 cases), and Staphylococcus aureus (2 cases). Streptococcus pneumoniae was significantly more frequent in patients with underlying disease and/or age > or =60 years (28% vs. 13%, P = 0.002), while Legionella pneumophila was more frequent in patients below 60 years of age and without underlying disease (20% vs. 9%, P = 0.006). Likewise, Streptococcus pneumoniae and Legionella pneumophila were the most frequent etiologies in patients requiring admission to the intensive care unit, occurring in 29% and 26.3% of the patients, respectively. In addition to Streptococcus pneumoniae, other microorganisms such as Chlamydia pneumoniae and Legionella spp. should be seriously considered in adults with community-acquired pneumonia when initiating empiric treatment or ordering rapid diagnostic tests.

[The impact of bronchial colonization in the quality of life of patients with chronic, stable bronchitis]. / Impacto de la colonización bronquial en la calidad de vida del paciente con bronquitis crónica estable.

BACKGROUND: The aim of this study was to determine the impact of respiratory function and bacterial colonization of the lower airway on the quality of life of patients with chronic, stable bronchitis (CB). MATERIALS AND METHODS: A series of 41 patients with stable CB was studied (age: 63.8; standard deviation (SD) 9.1 years; FVC% 91.0 (18.9); FEV1% 74.6 (23.7); FEV1/FEC 62.8 (11.2) with normal thoracic radiography. Patients with previous diagnosis of bronchiectasia, bronchial asthma and/or positive bronchodilatory tests (> 15%) were not included in the study. Bacterial growth in a sputum sample of grade 4-5 of the Murray-Washington scale was considered diagnostic of bronchial colonization. Measurement of the quality of life was performed with the Nottingham Health Profile (NHP) and the St. George Respiratory Questionnaire (SGRQ). RESULTS: The patients presented a moderate alteration in their quality of life with scores over 25 in most of the dimensions of the NHP and the SGRQ. In 9 out of 41 cases (22%), the sputum cultures demonstrated bronchial colonization with the most frequently isolated bacterias being Haemophilus influenzae and Moraxella catarrhalis. Multivariate analysis performed with the quality of life as the dependent variable showed an association between FEV1/FEC1 and the SGRQ score (R2 = 0.18), and energy (R2 = 0.09) and physical mobility (R2 = 0.05) of NHP. CONCLUSIONS: Bronchial obstruction is the main determinant in the quality of life in patients with stable CB. Colonization of the lower airway is observed in 22% of the patients and also influences the quality of life of the patients but to a much lesser extent.

Comparison of the Binax Legionella urinary antigen enzyme immunoassay (EIA) with the Biotest Legionella Urin antigen EIA for detection of Legionella antigen in both concentrated and nonconcentrated urine samples.

We evaluated a newly commercial enzyme immunoassay (EIA) (Biotest Legionella Urin Antigen EIA; Biotest AG, Dreieich, Germany) for detection of antigens of all Legionella pneumophila serogroups with a relatively wide spectrum of cross-reactivity as well as antigens of other Legionella spp. by comparing its sensitivity and specificity with those of an EIA for detection of L. pneumophila serogroup 1 antigen (Legionella urinary antigen EIA; Binax, Portland, Maine). Both tests were performed with both concentrated and nonconcentrated urine samples. We also evaluated the capabilities of both EIAs to detect extracted soluble antigens of American Type Culture Collection (ATCC) Legionella strains (L. pneumophila serogroups 1 to 14, L. bozemanii, and L. longbeachae). The sensitivity of the Biotest EIA was 66.66% in nonconcentrated urine and 86.66% in concentrated urine. The sensitivity of the Binax EIA was 63.76% and 88.88% in nonconcentrated and concentrated urine, respectively. The specificity was 100% in nonconcentrated and concentrated urine for both assays. The Binax EIA and Biotest EIA detected extracted soluble antigens of L. pneumophila serogroups 1 to 14 and L. bozemanii ATCC strains. The cross-reactions observed with the Binax EIA were probably due to common epitopes directly related to lipopolysaccharide. Further studies are required to determine the usefulness of the Binax EIA for detection of urinary antigens from Legionella species and serogroups other than L. pneumophila serogroup 1. The Biotest EIA proved to be as rapid, sensitive, and specific as the Binax EIA for the diagnosis of legionellosis. Concentration of antigen present in urine increased the sensitivities of both techniques with no reduction in specificity.

Comparative evaluation of two commercial assays for direct detection of Mycobacterium tuberculosis in respiratory specimens.

Two commercial systems for the amplification and detection of Mycobacterium tuberculosis directly from respiratory samples were compared. The Roche Cobas Amplicor MTB Test and the Roche manual Amplicor MTB Test (Roche Diagnostic Systems, USA) were applied to 755 decontaminated respiratory specimens collected from 470 patients. Results were compared with those of acid-fast staining and culture. A total of 251 specimens were collected from 156 patients diagnosed with pulmonary tuberculosis, including 28 specimens corresponding to 13 patients that were receiving antituberculous treatment. Given the overall positivity rate of 33.2% (251/755), the sensitivity, specificity, and positive and negative predictive values were 92.4, 100, 100, and 96.5%, respectively, for the Cobas Amplicor MTB Test and 90.8, 100, 100, and 95.8%, respectively, for the Amplicor MTB Test. For 204 (81.3%) smear positive specimens and 47 (19.7%) smear negative specimens, the sensitivity values were 100 and 59.6%, respectively, for the Cobas Amplicor MTB Test and 100 and 51%, respectively, for the Amplicor MTB Test. There were no statistically significant differences in sensitivity or specificity between the two assays and culture (p>0.05). The overall results of both assays were concordant for 99.5% of the samples. It is concluded that although both nucleic acid amplification methods are rapid and specific for the detection of Mycobacterium tuberculosis complex in respiratory specimens, the Cobas Amplicor MTB Test appears to be slightly more sensitive than the Amplicor MTB Test when smear negative specimens are investigated.

Evaluation of a commercial probe assay for detection of rifampin resistance in Mycobacterium tuberculosis directly from respiratory and nonrespiratory clinical samples.

A commercial assay (Inno-Line Probe Assay; Innogenetics, Belgium) was evaluated to determine its ability to detect rifampin resistance in Mycobacterium tuberculosis directly from clinical specimens. Fifty-nine selected specimens (42 respiratory and 17 nonrespiratory) culture positive for Mycobacterium tuberculosis were tested along with their corresponding isolates in culture. The results were compared with those obtained by in vitro susceptibility testing. The results of the line probe assay to detect rifampin resistance in Mycobacterium tuberculosis present in clinical specimens and in cultured isolates were concordant for 58 of 59 (98.3%) isolates (95% confidence limits = 90.9-99.9%). The line probe assay failed only once, when a fecal specimen was tested; no amplification was observed due to the presence of inhibitory compounds. The most frequently observed mutation was His526-->Asp (58.7%), followed by the His526-->Tyr (23.9%); together, they represented 82.6% of rifampin-resistant samples. In conclusion, the Inno-Line Probe Assay is a rapid, useful method for detecting the presence of Mycobacterium tuberculosis complex and its resistance to rifampin directly from clinical specimens and culture. Moreover, since rifampin resistance is a potential marker for multidrug resistance in Mycobacterium tuberculosis, this assay may constitute an important tool for the control of tuberculosis.

Rapid diagnosis of extrapulmonary tuberculosis by ligase chain reaction amplification.

A rapid amplification-based test for the diagnosis of extrapulmonary tuberculosis, the LCx Mycobacterium tuberculosis Assay from Abbott Laboratories, was evaluated. Results from the LCx M. tuberculosis Assay were compared with those from culture and the final clinical diagnosis for each patient. A total of 526 nonrespiratory specimens from 492 patients were tested. The specimens included urine; feces; lymph node exudates; pleural, cerebrospinal, articular, and ascitic fluids; tissue biopsies; gastric aspirates; purulent exudates; blood; and bone marrow aspirates. After combination of the culture results and the patient's clinical data, a total of 135 specimens were collected from 122 patients with a diagnosis of extrapulmonary tuberculosis. The sensitivity, specificity, and positive and negative predictive values for the LCx M. tuberculosis Assay were 77.7, 98.7, 95.2, and 93.1%, respectively; these values rose in resolved cases of TB to 78.5, 100, 100, and 93.1%, respectively. For 37 (27.4%) specimens from patients smear positive for the disease and 98 (72.6%) specimens from patients smear negative for the disease, the sensitivities of the LCx M. tuberculosis Assay were 100 and 71.1%, respectively. Statistically significant differences (P < 0.01) in sensitivities were found between culture and the LCx M. tuberculosis Assay. These differences were even greater among smear-negative specimens. The results demonstrate that the LCx M. tuberculosis Assay will provide rapid and valuable information for the diagnosis of extrapulmonary tuberculosis.

Comparative evaluation of initial and new versions of the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test for direct detection of Mycobacterium tuberculosis in respiratory and nonrespiratory specimens.

We evaluated the initial version of the Amplified Mycobacterium Tuberculosis Direct Test (Gen-Probe) (AMTDT 1) and the new version of AMTDT (AMTDT 2) for the detection of Mycobacterium tuberculosis directly from respiratory and nonrespiratory samples and compared the results with those of culture and staining methods. The assays were applied to 410 respiratory and 272 nonrespiratory samples collected from 515 patients. The combination of the culture results and clinical diagnosis was considered to be the "gold standard." Ninety-five respiratory specimens were collected from 67 patients with a diagnosis of pulmonary tuberculosis (TB) and 68 nonrespiratory specimens were collected from 61 patients with a diagnosis of extrapulmonary TB. With respiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 96%, respectively, for AMTDT 1 and 94.7, 100, 100, and 98.4%, respectively, for AMTDT 2. With nonrespiratory specimens, the sensitivity, specificity, and positive and negative predictive values were 83, 100, 100, and 94%, respectively, for AMTDT 1 and 86.8, 100, 100, and 98.4%, respectively, for AMTDT 2. The overall results of AMTDT 1 and AMTDT 2 were concordant for 97% (661 of 682) of the samples. Statistically significant differences in sensitivities were found between AMTDT 1 and AMTDT 2 with respiratory specimens. It was concluded that although both nucleic acid amplification methods are rapid, sensitive, and specific for the detection of M. tuberculosis complex in all types of clinical samples, AMTDT 2 appeared to be more sensitive than AMTDT 1 when applied to smear-negative specimens. In contrast AMTDT 2 is more susceptible than AMTDT 1 to inhibitory substances in the amplification reaction. The turnaround time of AMTDT 2 is shorter (3.5 h) than that for AMTDT 1 (5 h).

Role of immunosuppression in the evolution of Legionnaires' disease.

The clinical course of legionella pneumonia in immunosuppressed patients is uncertain. This study was undertaken to determine the clinical evolution of legionellosis on the basis of the immune state and to establish the variables associated with death directly related to legionellosis. The study included 78 patients: 28 with chronic disease who had received immunosuppressive treatment (group 1), 24 with chronic disease without immunosuppressive treatment (group 2), and 26 controls. Inclusion criteria were the occurrence of nosocomially acquired pneumonia, Legionella pneumophila infection, and erythromycin therapy that was initiated within 72 hours following diagnosis. Respiratory and extrarespiratory complications were observed more frequently in groups 1 and 2. Bilateral radiological involvement was most frequent in group 1, and recurrence of legionella pneumonia was observed exclusively in group 1. None of these variables achieved statistical significance. The global mortality of the series was 11.5% (17.9%, 12.5%, and 3.8% in groups 1, 2, and 3, respectively). Variables statistically related to mortality were acute renal failure, shock, and need for mechanical ventilation. Although many of the variables analyzed lacked statistical significance, a trend was seen between complications and basal immunosuppression, as previously suggested.

Comparison of a nonradiometric system with Bactec 12B and culture on egg-based media for recovery of mycobacteria from clinical specimens.

The MB/BacT (Organon-Teknika, USA) is a fully automated, rapid, nonradiometric system for the culture of mycobacteria from clinical samples. The rate of recovery of mycobacteria and the time to detection obtained with the MB/ BacT were compared with those obtained with Löwenstein-Jensen and Coletsos solid media and Bactec 7H12 (12B) (Becton-Dickinson, USA) broth when 600 processed specimens were inoculated into all media in parallel. Specimens included 383 respiratory samples, 20 urine samples, 23 purulent exudates, 13 stool samples, 103 blood samples, 14 bone marrow aspirates, and 44 body fluid samples or aspirates. Overall, 106 mycobacterial isolates comprising six species were recovered, of which 100 (94.3%) were detected with MB/BacT, 98 (92.5%) with egg-based media, and 96 (90.2%) with Bactec 12B. The recovery rates of Mycobacterium tuberculosis complex with MB/BacT, egg-based media, and Bactec 12B were 98.7%, 93.7, and 89.9%, respectively. The average number of days to detection of single mycobacterial isolates was 14.2 days for MB/BacT, 26.1 days for egg-based media, and 11.7 days for Bactec 12B. The contamination rates were higher in MB/BacT (5%) than in Bactec 12B (1.8%) or egg-based media (1.5%). MB/BacT is a reliable, nonradiometric, less labor-intensive alternative to Bactec 12B for recovery of mycobacteria, but, as with other liquid culture methods, MB/BacT should be used in combination with a solid medium, not on its own.