Impact of quality improvement in tuberculosis laboratories in low- and lower-middle-income countries: a systematic review.

BACKGROUND: The effect of quality improvement measures on the performance of diagnostic tuberculosis (TB) laboratories in low- and lower-middle-income countries is not known, and is the subject of this review. METHODS: Three databases were searched for quality improvement studies presenting data on performance parameters before and after the implementation of quality improvement interventions. RESULTS: Twenty-one studies were included in this review. Quality improvement measures were most frequently implemented by an external organization; settings targeted ranged from microscopy centers, hospitals, districts, regional and national reference laboratories. Quality improvement interventions and outcome measurements were highly heterogeneous. Most studies investigated interventions aimed at improving smear microscopy (n = 17). Two studies evaluated comprehensive quality improvement measures (n = 2) and another three studies focused on mycobacterial culture and drug susceptibility testing. Most studies showed an improvement in outcomes measured on before-after or time trend analysis. CONCLUSION: Quality improvement measures implemented in TB laboratories showed a positive impact on various outcomes. Due to the high heterogeneity of outcome reporting and interventions and the low quality of the studies, the effect size was not clear. Identification of standardized quality indicators and their link to the quality of patient care would improve knowledge in this field.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children

BACKGROUND: Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain. METHODS: A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS: Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional. CONCLUSIONS: These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

Three cases of donor-derived pulmonary tuberculosis in lung transplant recipients and review of 12 previously reported cases: opportunities for early diagnosis and prevention.

INTRODUCTION: Solid organ transplant recipients have a higher frequency of tuberculosis (TB) than the general population, with mortality rates of approximately 30%. Although donor-derived TB is reported to account for <5% of TB in solid organ transplants, the source of Mycobacterium tuberculosis infection is infrequently determined. METHODS: We report 3 new cases of pulmonary TB in lung transplant recipients attributed to donor infection, and review the 12 previously reported cases to assess whether cases could have been prevented and whether any cases that might occur in the future could be detected and investigated more quickly. Specifically, we evaluate whether opportunities existed to determine TB risk on the basis of routine donor history, to expedite diagnosis through routine mycobacterial smears and cultures of respiratory specimens early post transplant, and to utilize molecular tools to investigate infection sources epidemiologically. FINDINGS: On review, donor TB risk was present among 7 cases. Routine smears and cultures diagnosed 4 asymptomatic cases. Genotyping was used to support epidemiologic findings in 6 cases. CONCLUSION: Validated screening protocols, including microbiological testing and newer technologies (e.g., interferon-gamma release assays) to identify unrecognized M. tuberculosis infection in deceased donors, are warranted.

Mediastinal mass mimicking a tumor in a patient with bladder cancer after Bacillus Calmette-Guerin treatment.

We describe the case of a 78-year-old male with bladder cancer who developed a mediastinal mass after intravesical immunotherapy with live Mycobacterium bovis BCG. The clinical diagnosis was mediastinal tumor suggestive for lymphoma. However, cultures of the biopsy specimens grew an acid-fast organism, which was identified as M. bovis BCG. To the best of our knowledge, this is the first reported case in which a post-instillation BCG infection induced a mediastinal mass that mimicked a tumor in a patient with bladder cancer.

TB and HIV in St Petersburg, Russia: a looming catastrophe?

BACKGROUND: After decades of improved tuberculosis (TB) control in Russia, notification rates started to rise in 1992. Russia also faces a fast growing human immunodeficiency virus (HIV) epidemic. OBJECTIVE: To document the extent and characteristics of HIV co-infection in TB patients in St Petersburg, Russia. DESIGN: A prospective cross-sectional study of HIV coinfected culture-positive TB cases. Between 15 June 2002 and 31 March 2003, TB cases at the St Petersburg City TB hospitals and dispensaries were screened for HIV infection. At the HIV Prevention and Treatment Center, HIV-infected individuals were offered TB screening. RESULTS: Forty-nine HIV-infected culture-positive TB cases were identified, mainly at TB hospitals and dispensaries. Most were new pulmonary TB cases. The majority were young (69% < or = 30 years of age), male (84%), unemployed (94%) individuals with a history of injection drug use (IDU) (92%), and, in 35% of cases a history of incarceration. Active case finding was high among contacts of cases (9%), but was not successful in HIV-infected IDUs. CONCLUSION: Although the HIV seroprevalence rate is rising among TB patients, HIV does not yet appear to be driving the St Petersburg TB epidemic. Aggressive collaborative TB-HIV control efforts may still avert adverse effects of HIV on the TB epidemic.

Analysis of tuberculosis surveillance in Hungary in 2000.

SETTING: Hungary, Central Europe, with a population of 10.3 million living in 20 administrative districts (19 counties and the capital). OBJECTIVE: To summarize the results of the first year of the revised National Tuberculosis Surveillance System. DESIGN: Retrospective survey of the National Tuberculosis Surveillance Center (NTSC) database. METHODS: Analysis of data on all tuberculosis cases reported to the NTSC in 2000. Drug susceptibility results were evaluated in line with WHO and IUATLD definitions. RESULTS: During 2000, a total of 3598 patients with tuberculosis were reported. Only 40% of these were bacteriologically confirmed. Although susceptibility testing has been required for previously untreated culture-positive cases, only 801 (67.8% of the bacteriologically confirmed cases) were tested in 2000. Drug resistance was detected in 10.7% of previously untreated and in 23.5% of previously treated patients. Multidrug-resistant (MDR) cases were not common: only 1.5% of the isolates from previously untreated patients and 4.9% of those from previously treated patients were MDR. CONCLUSIONS: The results suggest that the NTSC should work towards increasing the numbers of cases that are bacteriologically confirmed. In addition, some form of surveillance system should be instituted to ensure that mandatory susceptibility testing is performed on all isolates from previously untreated tuberculosis patients.

The molecular basis of resistance to isoniazid, rifampin, and pyrazinamide in Mycobacterium tuberculosis.

Multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have emerged worldwide. In many countries and regions, these resistant strains constitute a serious threat to the efficacy of tuberculosis control programs. An important element in gaining control of this epidemic is developing an understanding of the molecular basis of resistance to the most important antituberculosis drugs: isoniazid, rifampin, and pyrazinamide. On the basis of this information, more exacting laboratory testing, and ultimately more appropriate and timely treatment regimens, can be developed.

Molecular characterization of rifampin-resistant isolates of Mycobacterium tuberculosis from Hungary by DNA sequencing and the line probe assay.

Two regions of rpoB associated with rifampin resistance were sequenced in 29 rifampin-resistant (determined by the proportion method) isolates of Mycobacterium tuberculosis obtained from patients from three counties in Hungary. Of the 29 resistant strains, 27 had a mutation in either the 81-bp region (26 strains) or the N-terminal region (1 strain), while the other 2 strains had no mutations in either region. The locations and frequencies of the mutations differed from those previously reported. The most common mutation in this study, D516V, was found in 38% of the Hungarian strains, a frequency 2 to 10 times higher than that found in studies from other countries. These same 29 isolates were also evaluated with the Inno-LiPA Rif. TB test (LiPA), a reverse hybridization assay for the rapid detection of rifampin resistance. Although LiPA detected the presence of an rpoB mutation in 26 of the resistant isolates, the type of mutation could not be determined in 4 isolates because the mutations present were not among those included on the LiPA strip. In addition, a silent mutation in one of the rifampin-susceptible control strains was interpreted as rifampin resistant by LiPA. These findings demonstrate the importance of validating this rapid molecular test by comparison with DNA sequence results in each geographic location before incorporating the test into routine diagnostic work.

Laboratory diagnosis of mycobacterial infections: new tools and lessons learned.

Even in the 21st century, tuberculosis continues to be a problem. Although the number of cases continues gradually to decrease in the United States, cases get more difficult to treat, specifically those that are multiple-drug resistant. Infection of one-third of the world's population ensures that tuberculosis will not disappear in the near future. In light of this, it will be useful to know the goals for the health care system and how these goals may be accomplished. Laboratory testing in the mycobacteriology field is experiencing more changes today than ever before. Determining what assays will be most useful to the clinician is a challenge, and acceptance of the new technology by the medical community an even greater one. Clinicians must use the best available resources to determine the most appropriate care for their patients and work together with the laboratory to ensure that the communication channels are open. This review focuses on current state-of-the-art resources useful for accurate and rapid laboratory diagnosis of mycobacterial infections.

Lessons from a proficiency testing event for acid-fast microscopy.

OBJECTIVES: To evaluate the routine performance and the technical parameters of different acid-fast staining methods: Kinyoun, Ziehl-Neelsen (ZN), auramine, and auramine-rhodamine. DESIGN AND PARTICIPANTS: The performance of 167 laboratories was analyzed using prestained and unstained slides. SETTING: Laboratories holding New York State permits. RESULTS: The results revealed that Kinyoun's cold carbol fuchsin method is inferior to both the ZN and fluorochrome (auramine and/or auramine-rhodamine) methods. Even though 91% of the participants used commercial staining kits, the study identified unexpected errors concerning the concentration of carbol fuchsin, time for staining and counterstaining, and the concentration of acid alcohol for decolorization, which may significantly influence the sensitivity. Besides these findings, the present study showed that the examination of < 300 view fields may also decrease the sensitivity of acid-fast microscopy. In addition, we found that the sensitivity and specificity of the ZN and fluorochrome methods are comparable if the procedural standards are followed. CONCLUSIONS: The strict and ongoing quality control of the "simple to perform" acid-fast microscopy and the immediate review of commercially available staining kits are necessary. Because of the rapidity of the fluorochrome method, laboratories with large specimen numbers should use this technique. In all other cases, the ZN method should be used. Moreover, all clinicians should be aware of the method of acid-fast microscopy used and the proficiency of the laboratory in performing the assay.

Cluster of tuberculosis cases in North Carolina: possible association with atomizer reuse.

BACKGROUND: Three patients with identical strains of M tuberculosis (TB) underwent bronchoscopy on the same day at hospital A. METHODS: We reviewed each patient's clinical history, hospital A's infection control practices for bronchoscopies, and specimen and isolate handling at each of 3 laboratories involved. We searched for possible community links between patients. Restriction fragment length polymorphism was performed on TB isolates. RESULTS: The first patient who underwent bronchoscopy had biopsy-confirmed granulomatous pulmonary TB. A sputum sample collected from the third patient 6 weeks after the bronchoscopy produced an isolate with an identical restriction fragment length polymorphism pattern to isolates collected during the bronchoscopies. No evidence existed for community transmission or laboratory contamination; the only common link was the bronchoscopy. Different bronchoscopes were used for each patient. Hospital ventilation and wall-suctioning were functioning well. Respiratory technicians reported sometimes reusing the nozzles of atomizers on more than one patient. A possible mechanism for transmission was contamination from the first patient of the atomizer if it was used to apply lidocaine to the pharynx and nasal passages of other patients. CONCLUSIONS: A contaminated atomizer may have caused TB transmission during bronchoscopy. Hospital A changed to single-use atomizers after this investigation.

Use of the National Committee for Clinical Laboratory Standards guidelines for disk diffusion susceptibility testing in New York state laboratories.

Accurate antimicrobial susceptibility testing is vital for patient care and surveillance of emerging antimicrobial resistance. The National Committee for Clinical Laboratory Standards (NCCLS) outlines generally agreed upon guidelines for reliable and reproducible results. In January 1997 we surveyed 320 laboratories participating in the New York State Clinical Evaluation Program for General Bacteriology proficiency testing. Our survey addressed compliance with NCCLS susceptibility testing guidelines for bacterial species designated a problem (Staphylococcus aureus and Enterococcus species) or fastidious (Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae) organism. Specifically, we assessed compliance with guidelines for inoculum preparation, medium choice, number of disks per plate, and incubation conditions for disk diffusion tests. We also included length of incubation for S. aureus and Enterococcus species. We found overall compliance with the five characteristics listed above in 80 of 153 responding laboratories (50.6%) for S. aureus and 72 of 151 (47.7%) laboratories for Enterococcus species. The most common problem was an incubation time shortened to less than 24 h. Overall compliance with the first four characteristics was reported by 92 of 221 (41.6%) laboratories for S. pneumoniae, 49 of 163 (30.1%) laboratories for H. influenzae, and 11 of 77 (14.3%) laboratories for N. gonorrhoeae. Laboratories varied from NCCLS guidelines by placing an excess number of disks per plate. Laboratories also reported using alternative media for Enterococcus species, N. gonorrhoeae, and H. influenzae. This study demonstrates a need for education among clinical laboratories to increase compliance with NCCLS guidelines.

False-positive results for Mycobacterium celatum with the AccuProbe Mycobacterium tuberculosis complex assay.

Mycobacterium celatum type 1 was found to cross-react in the AccuProbe Mycobacterium tuberculosis complex assay. Subsequently, we found a statistically significant increase in the relative light units with lower temperatures, suggesting that it is necessary to perform this AccuProbe assay at between 60 and 61 degrees C. We also recommend the inclusion of M. celatum type 1 as a negative control.

Access to newer laboratory procedures: a call for action.

Healthy People 2010, an initiative from the federal government, calls for action from tuberculosis controllers and tuberculosis laboratories in the fight to eliminate tuberculosis. Many patients, such as immunocompromised patients and those infected with multidrug-resistant tuberculosis strains, pose a challenge for care and diagnosis. Fortunately, many changes have occurred in the last decade to facilitate more rapid and accurate testing to assist with the care of these patients. California, Florida, New York and Texas have almost 50% of the tuberculosis cases in the United States, and their public health laboratories utilize different approaches to meet the same goal of rapid and accurate testing of specimens. With the targets of Healthy People 2010 (e.g., to reduce the average time for a laboratory to confirm and report tuberculosis cases to 2 days for 75% of cases) already looming on the horizon, innovative methods for achieving these goals should be evaluated. Using these public health laboratories as models, rapid, gold-standard testing methods should be provided to all patients in the United States. Soon it will be the year 2010..., are you ready to swiftly move forward?

Multicenter laboratory validation of susceptibility testing of Mycobacterium tuberculosis against classical second-line and newer antimicrobial drugs by using the radiometric BACTEC 460 technique and the proportion method with solid media.

In a large multicenter study involving six major study sites in the United States, Canada, and Europe, the susceptibilities of 272 Mycobacterium tuberculosis strains to classical second-line antituberculosis (anti-TB) drugs (capreomycin, cycloserine, ethionamide, and kanamycin) and newer compounds (amikacin, clofazimine, ofloxacin, and rifabutin) were determined by the radiometric BACTEC 460 procedure and the conventional proportion method on Middlebrook 7H10 agar. Previously established critical concentrations for classical second-line anti-TB drugs were compared with several concentrations in liquid medium to establish equivalence. MICs of newer compounds determined in liquid medium were either the same or up to four times lower than those determined in agar medium. After establishing critical concentrations (breakpoints) in the extended testing of clinical isolates, we obtained an excellent overall correlation between the two systems, with no errors with amikacin, kanamycin, and ofloxacin and very few major or very major errors with the other drugs; however, for cycloserine, no breakpoint concentration could be recommended due to repeatedly inconsistent results by both methods. Based on these data we conclude that the BACTEC 460 procedure is a simple and rapid method requiring 4 to 8 days on average to generate accurate antimicrobial susceptibility testing (AST) results for eight anti-TB drugs other than those considered primary ones. These data not only fill a major gap of knowledge regarding the critical test concentrations of secondary anti-TB drugs but also provide a baseline for future evaluations of M. tuberculosis AST with the more recently developed, nonradiometric broth-based culture systems.

Evaluation of mycology laboratory proficiency testing.

Changes over the last decade in overt proficiency testing (OPT) regulations have been ostensibly directed at improving laboratory performance on patient samples. However, the overt (unblinded) format of the tests and regulatory penalties associated with incorrect values allow and encourage laboratorians to take extra precautions with OPT analytes. As a result OPT may measure optimal laboratory performance instead of the intended target of typical performance attained during routine patient testing. This study addresses this issue by evaluating medical mycology OPT and comparing its fungal specimen identification error rates to those obtained in a covert (blinded) proficiency testing (CPT) program. Identifications from 188 laboratories participating in the New York State mycology OPT from 1982 to 1994 were compared with the identifications of the same fungi recovered from patient specimens in 1989 and 1994 as part of the routine procedures of 88 of these laboratories. The consistency in the identification of OPT specimens was sufficient to make accurate predictions of OPT error rates. However, while the error rates in OPT and CPT were similar for Candida albicans, significantly higher error rates were found in CPT for Candida tropicalis, Candida glabrata, and other common pathogenic fungi. These differences may, in part, be due to OPT's use of ideal organism representatives cultured under optimum growth conditions. This difference, as well as the organism-dependent error rate differences, reflects the limitations of OPT as a means of assessing the quality of routine laboratory performance in medical mycology.

Diagnostic tools in tuberculosis. Present and future.

Leadership will play a major role in the management of tuberculosis in the future. Many populations, such as immunocompromised patients and immigrants from countries with a higher prevalence of tuberculosis, create a challenge for care and diagnosis. Mycobacterial laboratory testing has undergone many changes in the past 10 years with the advent of nucleic acid probes for identification of Mycobacterium tuberculosis, and more recently nucleic acid amplification and beyond where computer technology meets molecular biology. In the past, changes for tuberculosis testing were not incorporated rapidly, sometimes taking 20 years or more to be fully implemented. The dynamics of acceptance of change and more rapid implementation need to be understood. With the use of such programs as Fast Track for Tuberculosis Testing, this can be accomplished more readily. New technologies can be provided to all users of such a network within a short amount of time and health care providers can equally benefit from this novel approach. The tuberculosis laboratory cannot stand alone. It must work together with other players, in order to eliminate tuberculosis.

Evaluation of a polymerase chain reaction-based universal heteroduplex generator assay for direct detection of rifampin susceptibility of Mycobacterium tuberculosis from sputum specimens.

In a double-blind study, 655 sputum specimens were obtained from individuals suspected of having tuberculosis and were analyzed for the presence of Mycobacterium tuberculosis and rifampin susceptibility with use of a polymerase chain reaction (PCR)-based universal heteroduplex generator assay (PCR/UHG-Rif). Of the specimens containing viable M. tuberculosis, 100% of the smear-positive (n = 41) and 50% of the smear-negative (n = 6) specimens tested positive for the organism by PCR/UHG-Rif. Nineteen of 537 culture-negative specimens tested positive for M. tuberculosis by PCR/UHG-Rif and were from patients with confirmed tuberculosis who were receiving antituberculosis therapy at the time of specimen collection. Thirty-five specimens contained nontuberculous mycobacteria and were negative by PCR/UHG-Rif. Genotypic evidence of rifampin resistance in five of six culture-confirmed, rifampin-resistant isolates was obtained by PCR/UHG-Rif, yielding a sensitivity and specificity for the assay of 83% and 98.2%, respectively. These results demonstrate the feasibility of using a PCR-based assay directly on sputum specimens for simultaneous detection of M. tuberculosis and rifampin susceptibility, and they suggest that patients with smear-positive, untreated tuberculosis and those presenting with suspected drug-resistant tuberculosis are the most appropriate groups for testing by PCR/UHG-Rif.