An alternative method for sputum storage and transport for mycobacterium tuberculosis drug resistance surveys.

SETTING: A district level tuberculosis (TB) programme in Indonesia. OBJECTIVE: To evaluate whether a single sputum specimen could be stored by refrigeration for an extended period of time, then transported to a reference laboratory and successfully cultured for Mycobacterium tuberculosis. METHODS: Single sputum specimens were collected from newly diagnosed smear-positive pulmonary TB patients, refrigerated at the study site without addition of 1% cetylpyridinium chloride, batched and sent to the reference laboratory, where they were decontaminated and inoculated into BACTEC MGIT 960 liquid media. RESULTS: One hundred and seven patients were enrolled. The median specimen storage time was 12 days (range 1-38) and median transportation time was 4 days (2-12). The median time from specimen collection until processing was 18 days (4-42). Only 4 (3.7%) specimens failed to grow Mycobacterium species and M. tuberculosis was isolated from 101 (94.4%) specimens. Six specimens with breakthrough contamination successfully grew M. tuberculosis after a second decontamination procedure. CONCLUSIONS: Single sputum specimens collected at a remote setting, refrigerated for relatively long periods without preservatives and transported without refrigeration to a reference laboratory can yield a high positive culture rate. These findings offer potential logistic simplification and cost savings for drug resistance surveys in low-resource countries.     

From microscopy centre to culture laboratory: a viable ride for mycobacteria.

SETTINGS: Culture and drug susceptibility testing of Mycobacterium tuberculosis is required for the treatment of drug-resistant tuberculosis. Cetylpyridinium chloride-sodium chloride (CPC-NaCl) solution is recommended for the preservation of sputum during transport. OBJECTIVE: To study the possibility of sputum preservation and transport in CPC-NaCl and its effect on culture. DESIGN: Sputum specimens preserved with CPC-NaCl were transported to the laboratory for culture from remote microscopy centres of Andhra Pradesh and Orissa states, India. RESULTS: Of the 175 specimens, 140 (80%) yielded mycobacteria, 21 (12%) did not yield any growth, 11 (6.2%) grew contaminants and 3 (1.7%) were lost due to leakage. Culture positivity was greater in specimens stored for 1 week. Culture results from specimens stored for 2 weeks are encouraging. CONCLUSION: The CPC-NaCl preservation technique can be used for effective preservation and transport of     

Broth culture: the modern 'guinea-pig' for isolation of mycobacteria

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.     

Evaluation of a polymerase chain reaction for the diagnosis of tuberculosis

A polymerase chain reaction for the specific detection of Mycobacterium tuberculosis has been developed and evaluated for clinical applicability. Primers were designed to amplify a 240 base pair region in the MPB 64 protein coding gene (nts 460-700). From among 15 different DNA templates tested (including 10 species of mycobacteria) PCR amplified the DNA from M. tuberculosis complex only, demonstrating its exquisite specificity. Sensitivity studies using serial ten-fold dilutions of M. tuberculosis bacilli determined the limit of detectability to be 10 organisms. A total of 143 clinical specimens were analysed. This consisted of 26 known non-tuberculous specimens (control group) and 117 specimens received at the Tuberculosis Diagnostic Service of AIIMS (test group). None of the specimens in the control group was positive by PCR. Out of 117 specimens in the test group, 19 were culture positive for mycobacteria and 17 of these isolates were identified as M. tuberculosis. All the specimens from which M. tuberculosis was grown were also PCR positive. The remaining two isolates were identified as mycobacteria other than M. tuberculosis and these two specimens were PCR negative. An additional 14 culture negative specimens were PCR positive yielding an overall M. tuberculosis positivity rate of 26.5% (31/117) compared to 14.5% (17/117) by culture. The superior sensitivity of PCR over culture was more evident in non-pulmonary cases where PCR picked up 10 cases in addition to three culture positives out of 69 specimens. On the other hand, out of 48 pulmonary specimens only four cases in addition to 14 culture positives were picked up by PCR.     

Line probe assay in the rapid detection of rifampin-resistant Mycobacterium tuberculosis directly from clinical specimens.

The sensitivity of a PCR-based line probe assay (Inno-LiPA Rif. TB Assay; Innogenetics NV Zwijndrecht, Belgium) was studied by using nested-PCR technique. A total of 75 specimens, representing various body locations from 70 suspected tuberculosis patients were obtained. LiPA yielded 30 Mycobacterium tuberculosis complex positive results (sensitivity 58.8%, compared with final diagnoses) whereas culture for M. tuberculosis was positive in 18 specimens (sensitivity 35.3%). Genotypic rifampin resistance testing by LiPA showed that 7 specimens contained rpoB mutations associated with RMP resistance, and sequencing data of the rpoB gene and LiPA patterns agreed in 29 of 30 M. tuberculosis positive specimens (96.7%). This indicates reliable performance, which makes the test suitable for the rapid determination of resistance to rifampin directly in clinical samples. However, the best results are obtained if LiPA is combined with conventional staining and culture methods.     

Evaluation of the Idaho Technology LightCycler PCR for the direct detection of Mycobacterium tuberculosis in respiratory specimens.

SETTING: The rapid detection of Mycobacterium tuberculosis (TB) in clinical samples is an important goal. The LightCycler heralds an advance in thermal cycle technology combining rapid cycle DNA amplification with fluorimetry, eliminating the need to perform amplification and product analysis separately. OBJECTIVES: To evaluate the LightCycler for direct detection of M. tuberculosis complex in respiratory specimens. To evaluate a DNA extraction method based on Chelex 100 resin, heating and ultrasonication for the prevention of endogenous inhibitions in respiratory samples. DESIGN: DNA was extracted from sputum samples using the Chelex method and polymerase chain reaction (PCR) for TB performed with the LightCycler. RESULTS: For 88 sputum samples positive by microscopy and culture for M. tuberculosis, 95% were PCR-positive. None of the five sputum samples that were smear-negative but culture-positive for M. tuberculosis, the 79 culture-negative sputum samples and the 29 sputum samples that were culture-positive for mycobacteria other than TB yielded positive PCR results. PCR inhibitors were not detected in any of the samples. CONCLUSION: The LightCycler proved a simple, reproducible and rapid system, reducing the time to result from weeks (culture) or days (conventional PCR) to hours. The Chelex 100 resin method produced good results for the smear-positive specimens. However, a larger study is required to determine the efficacy of the method with smear-negative specimens and for specimens known to contain endogenous inhibitors.     

肺结核患儿胃液样本结核分枝杆菌培养阳性率提高方法的探讨

目的:建立提高肺结核患儿胃液样本结核分枝杆菌(Mycobacterium tuberculosis,MTB)培养阳性率的方法,同时,探讨培养液的pH值对MTB抗原-胶体金检测试剂正确判读结果的影响和磷酸盐缓冲液(phosphate buffer solution, PBS)对结核样本前处理液pH值的调节作用。方法:将70份疑似肺结核患儿胃液样本同时用两步培养法、传统培养法和Xpert Ultra进行检测。两步培养法为先将胃液样本直接接种到罗氏培养基上,约20～30 d后收集可疑MTB菌落再行常规的碱处理-中和离心法处理进行分离培养(传统培养法)。比较传统培养法和两步法阳性检出率的差异;以样本的Xpert Ultra检测结果作为菌载量标准,分析两步法在不同菌载量样本中的阳性检出率差异。同时,配制系列pH值梯度的溶液,确定MTB抗原-胶体金检测试剂获得最佳显示结果的最适pH值范围;用系列体积的PBS缓冲液(pH=6.8)中和3%或4%NaOH与等体积样本的混合液,确定pH值至7～9时所需的体积稀释倍数。结果:传统培养法阳性检出率为26.5%(18/68),两步法阳性检出率为23.1%(15...     

结核病房空气中结核分支杆菌检测方法研究

目的探索空气中结核分支杆菌检测的有效方法。方法选用ＬＷＣ－Ⅰ型空气微生物采样器，对菌阳肺结核病房进行空气采样，３０份采样标本分别用不同方法检测结核分支杆菌。结果聚合酶链反应（ＰＣＲ）阳性１４份，阳性率４７％；Ｓｏｕｔｈｅｒｎ转印杂交阳性１８份，阳性率６０％；动物接种实验组３０只豚鼠有２只结核分支杆菌培养阳性，另１只病理组织学检查阳性，而对照组１０只豚鼠脏器培养及病理组织学检查全部阴性；罗氏培养和ＢＡＣＴＥＣ快速培养均呈阴性。结论用空气采样的方法进行空气中结核分支杆菌的监测是可行的。ＰＣＲ和Ｓｏｕｔｈｅｒｎ转印杂交最敏感，动物实验也可提供有意义的参考。     

A multicenter study of a new Helicobacter pylori selective medium. Columbia horse blood agar HP

We conducted a study for the growth of and selectivity for the desired microorganisms using a newly developed selective culture medium for Helicobacter pylori, Columbia horse blood agar HP (CHBHP), at three different Japanese clinical laboratories, Hokkaido, Kanto and Kyusyu. When standard strains and clinical isolates of H. pylori were examined, the recovery of the organism on the CHBHP media was comparable to that of conventional selective and nonselective media. However, colonies were obviously larger on the CHBHP media. These media yielded the highest H. pylori positive rate for clinical specimens at all the three laboratories. The detection rate of the CHBHP media in H. pylori-positive specimens was higher than that of media commonly used at the three laboratories (98.1% to 100% vs. 88.0% to 96.2%). The CHBHP media also achieved a higher detection rate for specimens from H. pylori-infected animals. CHBHP media have an excellent growth supporting ability and selectivity originating from Columbia agar base and do not require the combined use of non-selective media for the growth and isolation of the organism, resulting in lower cost. Thus, they are useful media for the selective culture and isolation of H. pylori from clinical and animal specimens.     

Efficacy of Amplicor PCR for the diagnosis of tuberculosis in respiratory specimens other than sputum.

A total of 832 respiratory specimens not including the sputum (402 bronchial lavages, 241 bronchial brushing specimens, 136 pumping lavages, 41 pleural effusions, and 12 others) from 462 patients were assayed using the Roche Amplicor Mycobacterium tuberculosis test for amplification and identification of M. tuberculosis, M. avium and M. intracellulare (Amplicor PCR). The results were compared with those obtained using conventional microscopy and cultivation methods. Each patient had little or no sputum and showed an abnormal chest X-ray shadowing of unknown cause. No patients had previously undergone antituberculous therapy. Of the specimens obtained, 24 were both PCR and culture positive, 786 were both PCR and culture negative, 11 were PCR positive and culture negative, and 11 were PCR negative and culture positive. Based on these results, the sensitivity and specificity of Amplicor PCR were determined to be 68.67% and 98.6%, respectively, when compared with culture of respiratory specimens not including the sputum. After correcting for discrepancies due to differences in patient clinical data, the sensitivity of Amplicor PCR was found to be 68.6%, and the specificity to be 99.9%; the corresponding values for culture were 66.7% and 100%, and those for smear were 9.8% and 100%. Thus, Amplicor PCR was shown to possess a similar sensitivity to culture and to be a highly specific technique for the diagnosis of tuberculosis in the respiratory system using non-sputum specimens within hours in patients showing little or no sputum and abnormal chest X-ray shadowing of an indeterminant cause.     

Evaluation of the FASTPlaqueTB assay for direct detection of Mycobacterium tuberculosis in sputum specimens.

SETTING: Sputum samples were collected from suspected tuberculosis patients attending out-patient clinics at the Ojha Institute of Chest Diseases, Karachi, Pakistan. OBJECTIVE: To evaluate the performance of the FASTPlaqueTB assay for rapid diagnosis of pulmonary tuberculosis. DESIGN: A comparative study of 584 sputum samples using acid-fast smear microscopy, Lowenstein-Jensen culture and FASTPlaqueTB. RESULTS: A total of 514 samples yielded complete results. Seventy specimens were lost to analysis due to the overgrowth of contaminants. The addition of antimicrobials inhibited growth of gram-positive contaminants, and reduced the overall contamination rate from 18.2% to 7.2%. Mycobacterium tuberculosis was isolated from 175 smear-positive and 70 smear-negative specimens. FASTPlaqueTB detected M. tuberculosis in 81.6% of specimens, with a specificity of 97.7%. The sensitivity and specificity of the assay for smear-positive specimens were respectively 87.4% and 88.2%. For smear-negative specimens, the sensitivity of the assay was 67.1% and the specificity was 98.4%. The combined sensitivity of smear and FASTPlaqueTB for M. tuberculosis was 90%. Test results were available in 48 hours. CONCLUSION: FASTPlaqueTB is a sensitive and specific test for rapid diagnosis of pulmonary tuberculosis in high prevalence areas. The test is sensitive enough to confirm a large number of clinically suspected smear-negative cases and improve case finding.     

标本处理方法对聚合酶链反应检测结核分支杆菌结果的影响

目的探讨应用十二烷基硫酸钠（SDS）处理标本在结核分支杆菌聚合酶链反应（PCR）中的价值。方法从186例活动性结核病人收集痰、胸腹水、脑脊液、尿、血液等标本266份,标本分别用SDS和常规方法进行处理。两种方法处理的标本同时用PCR-反相膜杂交试验检测结核分支杆菌,并将结果进行比较。结果用SDS和常规方法处理的标本,PCR-反相膜杂交试验结核分支杆菌的检出率分别为65.0%（173/266）和51.5%（136/266）。通过配对计数资料卡方检验,SDS法和常规法之间的差异具有非常显著性意义（χ     

Microbiology of pediatric primary pulmonary tuberculosis

OBJECTIVE: To determine the sensitivity of bacteriologic studies in pediatric pulmonary tuberculosis. PATIENTS AND METHODS: Between January 1988 and December 1996, 104 consecutive patients aged 0 to 18 years received a diagnosis of primary pulmonary tuberculosis at our institution. Demographic, clinical, laboratory, and bacteriologic data were collected. Clinical specimens were studied for acid-fast bacilli detection by Ziehl-Neelsen stain and cultured for Mycobacterium recovery by Lowenstein-Jensen culture medium. Statistical analysis was performed utilizing chi(2), t tests, and multivariate logistic regression analysis. RESULTS: Bacteriologic results were available for 57 patients (54.8%). A positive smear or culture result for Mycobacterium tuberculosis was obtained in 9 of 54 patients (16.6%) and 25 of 50 patients (50%), respectively. Confirmation of M tuberculosis disease was achieved in 28 patients (49.1%). Ziehl-Neelsen stain and Lowenstein-Jensen culture recovery rates were 10.3% (14 of 135) and 52% (48 of 92) of specimens studied, respectively. Sputum, pleural fluid, and biopsy material cultures yielded M tuberculosis in 55%, 75%, and 63% of patients, respectively. Mean +/- SD age (13.7 +/- 4.5 years vs 9.6 +/- 4.5 years) and number of samples submitted for culture (1.93 +/- 0.94 vs 1.31 +/- 0.97) were significantly higher in the confirmed tuberculosis disease group (p < 0.05). The presence of a pleural effusion was also more commonly found in the confirmed tuberculosis disease group (p < 0.05). CONCLUSION: The sensitivity of bacteriologic studies in pediatric pulmonary tuberculosis disease was 49.1%. Age is the main factor associated with the positivity of culture results.     

Rapid and efficient detection of extra-pulmonary Mycobacterium tuberculosis by PCR analysis.

SETTING: The diagnosis of extra-pulmonary tuberculosis (EPTB) remains an important clinical problem, primarily because of the inadequate sensitivity of conventional bacteriologic methods for detecting Mycobacterium tuberculosis in extra-pulmonary specimens. OBJECTIVE: To evaluate whether a IS6110-based polymerase chain reaction (PCR) method can be utilized to detect M. tuberculosis in non-pulmonary specimens. DESIGN: Specimens from 286 Mexican patients with a presumptive clinical diagnosis of EPTB were prospectively examined by Ziehl-Neelsen staining, mycobacterial culture on L?wenstein-Jensen slants, and by PCR. The DNA for PCR was extracted by the buffer lysis method and phenol-guanidine thiocyanate-chloroform. Primers that amplify a 200 bp fragment from the insertion-like M. tuberculosis sequence element IS6110 were utilized. RESULTS: Our results demonstrate that this PCR method is highly specific (100%) for identifying M. tuberculosis from a variety of specimens including cerebrospinal fluid (CSF), pleural fluid, ascitic fluid, pericardial fluid, urine, and lymph node exudate. Moreover, the sensitivity of PCR for detecting M. tuberculosis in CSF (94%), pleural fluid (94%), ascitic fluid and other extrapulmonary specimens (93%) greatly exceeds the sensitivity of conventional smear and culture methods. CONCLUSION: These results demonstrate that PCR can be a highly specific and sensitive aid in the detection of M. tuberculosis from extra-pulmonary specimens.     

Costs and cost-effectiveness of tuberculosis cultures using solid and liquid media in a developing country

SETTING: The expansion of culture has been proposed to aid tuberculosis (TB) control in developing countries. OBJECTIVES: To examine the cost and cost-effectiveness at the Zambian National TB Reference Laboratory of homemade and commercially produced L?wenstein-Jensen culture (HLJ and CLJ) as well as automated and manually read liquid culture (AMGIT and MMGIT). DESIGN: Costs were estimated from the provider's perspective and based on the average monthly throughput. Cost-effectiveness estimates were based on yield during the study period. RESULTS: All techniques show comparable costs per culture (between US$28 and $32). Costs per Mycobacterium tuberculosis specimen detected were respectively US$197, $202, $312 and $340 for MMGIT, AMGIT, CLJ and HLJ. When modelled for the maximum throughput, costs were above US$95 per M. tuberculosis specimen detected for all techniques. When only performed among smear-negative specimens, costs per additionally identified M. tuberculosis would be US$487 for MMGIT and higher for other methods. CONCLUSION: Based on cost-effectiveness grounds, liquid media compare well with conventional solid media, especially where yield of MGIT is substantially higher than that of LJ media. The results indicate high overall costs per culture; the expansion of culture to decentralised levels with lower throughputs may result in even higher costs.     

Assessment of the Mycobacteria Growth Indicator Tube for the bacteriological diagnosis of tuberculosis.

Fast, accurate diagnosis is necessary for rapid treatment of patients and to prevent the spread of Mycobacterium tuberculosis strains. The rate of recovery, mean time to detection and contamination rates of the Mycobacteria Growth Indicator Tube (MGIT) were compared with Lowenstein-Jensen (LJ) medium for mycobacterial cultures performed on 405 clinical specimens decontaminated by the trisodium phosphate method without benzalkonium chloride. The recovery rate of M. tuberculosis using MGIT was 45/61 (73.8%) compared with the reference LJ. The mean times to detection of M. tuberculosis in smear-positive specimens were 11.9 days with MGIT and 20 days with LJ. For smear-negative samples, the mean times were respectively 18.6 and 31 days, and the contamination rates were respectively 4% and 1.2%. When the trisodium phosphate decontamination method is used, MGIT cannot be used alone for isolation of mycobacteria, but may be used in combination with LJ.     

The role of simultaneous combination culture with solid and liquid media for diagnosis of pulmonary tuberculosis

PURPOSE: To study the usefulness of simultaneous combination culture with egg-based Ogawa medium (1 slant) and MGIT (Mycobacterium growth indicator tube/Becton-Dickinson) for detection of M. tuberculosis from sputum in sputum-culture proven pulmonary tuberculosis patients. OBJECT AND METHOD: Retrospective study of sputum-culture-positive pulmonary tuberculosis cases in our hospital (with tuberculosis ward) from Jan. 2002 to Sept. 2003. RESULT: In 1103 sputum culture for the diagnosis of 370 sputum-culture proven pulmonary tuberculosis cases, 86.0% were MGIT positive and 79.5% were Ogawa positive. Among sputa contaminated on MGIT, 56.1% (23/41) were positive on Ogawa. Among sputa culture-negative on MGIT, 2.7% (3/113) were positive on Ogawa. Those 3 sputa were obtained from 3 different patients, and in 2 of them, other sputa were positive on MGIT. Frequency of "M. tuberculosis strain which can be cultured only by Ogawa" was supposed to be at maximum 0.27% (1/370). Of 41 sputa contaminated on MGIT, 15 sputum specimens were re-treated and re-cultured by MGIT. Of these specimens 46.7% (7/15) were positive on Ogawa, and 73.3% (11/15) were positive on re-treated MGIT, and the difference was not statistically different. CONCLUSION: From the standpoint of detection of M. tuberculosis from sputum in sputum-culture proven pulmonary tuberculosis patients, simultaneous combination culture of Ogawa medium with MGIT is useful, mainly for risk management of MGIT contamination. But, if re-treated MGIT is done for cases of contaminated on MGIT, simultaneous combination culture of Ogawa medium with MGIT is not necessary.     

Measurement of sputum Mycobacterium tuberculosis messenger RNA as a surrogate for response to chemotherapy.

Effective treatment regimens for pulmonary tuberculosis are difficult to assess because of the slow growth rate of Mycobacterium tuberculosis in culture and its protracted clearance from sputum. A rapid method that reflects effective antimicrobial activity would markedly advance evaluation of treatment and promote the assessment of new antituberculosis drugs. Conventional methods measure the progressive reduction of numbers of acid-fast bacilli in the sputum smear and the clearance of organisms in sputum culture. In this study, we measured levels of M. tuberculosis 85B (alpha antigen) messenger RNA (mRNA), 16S ribosomal RNA (rRNA), and IS6110 DNA in patients' sputa to ascertain whether they could serve as potential surrogate markers of response to chemotherapy. Sputum specimens were sequentially collected for up to a year from 19 smear-positive pulmonary tuberculosis patients receiving an optimal drug treatment regimen. Nucleic acids were isolated from these specimens, and two M. tuberculosis molecular targets (mRNA, DNA) were quantified, using the ABI Prism 7700 Sequence Detection System. The Mycobacterium genus-specific 16S rRNA was quantified with a limiting dilution RT-PCR assay. Results show that levels of 85B mRNA declined after initiation of therapy, as did viable M. tuberculosis colony counts, with 90% of patients becoming negative for both markers after 2 mo of treatment. The rapid disappearance of M. tuberculosis mRNA from sputum suggests that it is a good indicator of microbial viability and a useful marker for rapid assessment of response to chemotherapy.     

Evaluations of MTD and Amplicor Mycobacterium for direct detection of Mycobacteria from clinical specimens]

MTD (GEN-PROBE AMPLIFIED MYCOBACTERIUM TUBERCULOSIS DIRECT TEST) for Mycobacterium tuberculosis, and Amplicor Mycobacterium for Mycobacteria (AMP-M. tb for M. tuberculosis, AMP-M. av for M. avium and AMP-M. in for M. intracellulare) were used for the detection of relevant Mycobacterium. Their sensitivity and specificity were evaluated. Total 244 clinical specimens including 164 sputa were examined by the above two tests. The results were compared with those obtained by the conventional methods. Of 244 samples, number of the M. tuberculosis positive samples by microscopy, cultural test, MTD and AMP-M. tb were 32, 33, 38 and 35, respectively. Among 33 culture positive samples, 25 were MTD positive and 26 were AMP-M. tb positive. Therefore, sensitivity of MTD and AMP-M. tb were 75.8% and 78.8%, and their specificity were 93.8% and 95.7%, respectively. When only sputa were used for the tests as the clinical specimens, both sensitivity of MTD and AMP-M. tb were increased to 94.4%. For MAC, positive samples of M. avium complex by culture, M. avium by AMP-M. av and M. intracellulare by AMP-M. in were 13, 16, and 8, respectively. Sensitivity and specificity of AMP-M. av/M. in were 100% and 95.2%, respectively. Clinical findings of the patients whose MTD tests were positive but negative by culture were reexamined. Three of 9 specimens were also positive in AMP-M. tb. From the records of the isolations of tubercle bacilli or other important pathogens from the other kind of clinical specimens, smear tests and patients' response to tuberculosis chemotherapy, four of 9 specimens were confirmed as true positive, three were suspected as positive, and two other specimens were false positive which might be caused by contamination. From these observations, it could be concluded that MTD and AMP-M. tb are more sensitive than conventional culture method, and MTD is more sensitive than AMP-M. tb but needs more careful treatment to avoid the contamination.     

Improved recovery of Mycobacterium tuberculosis from pleural aspirates: bedside inoculation, heparinized containers and liquid culture media

The effects of bedside inoculation, heparinized containers and liquid culture media on the recovery of Mycobacterium tuberculosis from pleural aspirates were evaluated in this study. Of 155 patients, 63 were diagnosed to have pleural effusion tuberculous in origin. The overall recovery of M. tuberculosis was 57.1%. Bedside inoculation of the specimens produced a significantly higher yield than laboratory inoculation using non-heparinized specimens. When the pleural aspirates were transported in heparinized containers, the recovery rate was comparable to that from bedside inoculation, but lower when non-heparinized containers were used. No significant difference was found in recovery rate between the two liquid media, but the rate was significantly higher with the use of liquid media than conventional solid media. Thus, bedside inoculation of pleural aspirates, use of heparinized containers for transport for delayed inoculation in the laboratory and use of liquid culture media are recommended.