Identification Of Acid-fast Bacilli Research Articles

Localization and phenotyping of tuberculosis bacteria using a combination of deep learning and SVMs

Successful treatment of pulmonary tuberculosis (TB) depends on early diagnosis and careful monitoring of treatment response. Identification of acid-fast bacilli by fluorescence microscopy of sputum smears is a common tool for both tasks. Microscopy-based analysis of the intracellular lipid content and dimensions of individual Mycobacterium tuberculosis (Mtb) cells also describe phenotypic changes which may improve our biological understanding of antibiotic therapy for TB. However, fluorescence microscopy is a challenging, time-consuming and subjective procedure. In this work, we automate examination of fields of view (FOVs) from microscopy images to determine the lipid content and dimensions (length and width) of Mtb cells. We introduce an adapted variation of the UNet model to efficiently localising bacteria within FOVs stained by two fluorescence dyes; auramine O to identify Mtb and LipidTox Red to identify intracellular lipids. Thereafter, we propose a feature extractor in conjunction with feature descriptors to extract a representation into a support vector multi-regressor and estimate the length and width of each bacterium. Using a real-world data corpus from Tanzania, the proposed method i) outperformed previous methods for bacterial detection with a 8% improvement (Dice coefficient) and ii) estimated the cell length and width with a root mean square error of less than 0.01%. Our network can be used to examine phenotypic characteristics of Mtb cells visualised by fluorescence microscopy, improving consistency and time efficiency of this procedure compared to manual methods.

Sharma's parachute sign a new laparoscopic sign in abdomino pelvic tuberculosis

AimsTo demonstrate a new laparoscopic sign “Sharma's Parachute sign” in abdominopelvic tuberculosis in women with infertility. MethodsA total of 104 women who were diagnosed to have abdominopelvic tuberculosis, on endometrial sampling or on laparoscopy were enrolled in this ongoing study on tuberculosis in infertility. A new laparoscopic “Sharma's parachute sign” was looked for in these cases on laparoscopy. ResultsThe mean age, pairty and duration of infertility was 27.6 years, 0.58 and 4.1 years respectively. Menstrual dysfuction were common especially hypomenorrhoea (34.61%), oligomenorrhoea (36.53%) along with constitutional symptoms and abdomino pelvic pain or lump. Diagnosis of abdominopelvic tuberculosis was made by identification of acid fast bacilli (AFB) on microscopy or culture of endometrial aspirate or peritoneal biopsy or positive gene Xpert or positive polymerase chain reaction (PCR) or histopathological demonstration of epithelioid granuloma on endometrial or peritoneal biopsy, various laparoscopic findings on pelvic and abdominal organs were tubercles and shaggy areas (white deposits, caseous nodules encysted ascites, abdominal and pelvic adhesions, tubal findings (hydrosalpinx, pyosalpinx, beaded or calcified tubes). A new “Sharma's parachute sign”in which ascending colon was totally adherent to anterior abdominal wall with its mesocolon looking like an open parachute with small caseous nodule was seen in 11 (10.5%) cases. ConclusionDiagnostic laparoscopy is an important investigation for abdominopelvic tuberculosis showing various adhesions including new parachute sign.

Possible Immunological Alterations in the Plasma Levels of TNF-α and IL-10 in the Traditional Application of Vernonia Amygdalina (Ewuro) Leaves in the Treatment of Diabetes Mellitus

Diabetes mellitus can induce release of free radicals and oxidative stress, which can trigger production of cytokines. Vernonia amygdalina has antidiabetic activity due to its phytochemical constituents. This work was designed to determine possible immunological alterations in the plasma levels of TNF-α and Interleukin-10 (IL-10) in the traditional application of V. amygdalina (Ewuro) leaves in the treatment of diabetes mellitus. The study populations include all 33 diabetes mellitus patients (51-67 years; male, 21; female, 12) who had not commenced any form of medication or treatment and received herbal treatment in 10 herbal homes of Saki West, a local government area in Nigeria. Twenty-seven agematched volunteers who were treated on insulin medication in the hospital almost within the same period were also investigated. Patients who were positive to acid-fast bacilli sputum test, Plasmodium spp., identification, HBsAg, anti-HCV, and HIV-1 p24 assays were not included. Plasma TNF-α, IL-10, HBsAg, anti-HCV, and HIV-1 p24 were determined in the patients by ELISA while identification of acid-fast bacilli and Plasmodium spp. were carried out by Ziehl-Neelsen and Giemsa thick blood-film staining, respectively. There was a significant decrease in the plasma levels of TNF-α, IL-10, and glucose in diabetes mellitus patients after the administration of raw liquid extract of V. amygdalina and insulin compared to their basal samples before the commencement of the treatment (p < 0.05). The work revealed a significant increase in plasma TNF-α, IL-10, and glucose in diabetes patients, which returned to normal plasma values after treatment using raw liquid extract of V. amygdalina leaves and insulin.

Nasal Tuberculosis in a Teenage Female.

Although cutaneous tuberculosis (TB) is a rare form of extra-pulmonary TB, lupus vulgaris is the commonest variant of cutaneous TB. We present a 14year female with non-healing ulcer over the upper lip extending and destroying the collumela and part of anterior nasal septum. Histopathological examination revealed TB as a possible cause of the lesion. Identification of acid-fast bacilli on direct stained smears confirms the diagnosis of TB. Complete healing of the ulcer was achieved with anti-tuberculous regime leaving a residual fibrosis over the site of the ulcer.

Comparison between tests for tuberculosis diagnosis in slaughtered bovines

ABSTRACT: Our goal for this article is to compare several different diagnosis tests for bovine tuberculosis identification. We have performed bacterial isolation, histopathological characterization, acid-fast bacilli (AFB) identification and M. bovis DNA detection. Lesions suggestive of Tuberculosis were sampled from bovine lymph nodes during slaughtering of bovines at an abattoir that operates under federal inspection. The bacterial isolation was performed in solid culture mediums, the histopathological characterization was made by Hematoxylin-eosinstaining, and AFB identification by Ziehl-Neelsen staining. Bacterial DNA detection was performed by Polymerase Chain Reaction (PCR) using DNA from two different sources, directly collected from the tuberculosis-like lesions (PCR followed by nested PCR) and from isolated bacteria. We have concluded that the multi-step approach, including histopathological characterization, bacterial isolation and AFB identification, is strongly recommended to diagnose tuberculosis in bovines. Furthermore, PCR assays using specimens of lesions suggestive of tuberculosis are a faster and more promising way to diagnose the disease. However, it should not be used alone due to the low sensitivity shown in this study.

Isolation and identification of Mycobacterium bovis in cattle slaughtered from an abattoir in Garanhuns, Pernambuco

Tuberculosis is a chronic infectious disease caused by the Mycobacterium tuberculosis complex (CMT), members including M. bovis. The sanitary inspection in slaughterhouses has a great importance on public health for the removal of contaminated meat with pathological lesions. Cattle slaughtered in the abattoir of Garanhuns were subjected to macroscopic, histological, bacteriological, and molecular analyses. Lung inspection revealed gross lesions suggestive of tuberculosis. The characterization of tuberculous granulomas was performed by histopathology and hematoxylin and eosin (HE) staining. The identification of acid-fast bacilli (AFB) was performed on smears with fresh material and histological staining using Ziehl-Neelsen stain. Bacteriological diagnosis was carried out using Stonebrink and Lowenstein-Jensen media, and polymerase chain reaction (PCR) was performed from the DNA extracted from colonies for the identification of Mycobacterium spp. We found that 1% (32/3,.180) of the collected lungs showed lesions suggestive of tuberculosis. Histopathological analysis revealed that 65.62% (21/32) samples had granulomatous pneumonia. AFB was detected in 46.88% (15/32) smears and 4.16% (1/24) histological sections, as analyzed by Ziehl-Neelsen staining. Moreover, 68.75% (22/32) samples showed bacterial growth and molecular identification 90% (18/20) of the samples were positive for M. bovis and 10% (2/20) for Mycobacterium sp. Thus, microbiological culture and PCR analyses revealed the high rate of bovine tuberculosis in this region, indicative of the need to disclose these results in the interest of public health. Consequently, we emphasize the need for an accurate macroscopic evaluation of lesions suggestive of bovine tuberculosis.

Difficulties in diagnosis of bovine tuberculosis in suggestive lesions on post-mortem inspection in carcasses

The bovine tuberculosis is a zoonotic disease with importance to the public health. The post mortem identification and its fast and accurate diagnosis combined with the epidemiology knowledge are essential to fight against the advance of this disease. Therefore, the present study aimed to perform the diagnosis of Mycobacterium bovis, by molecular detection and also by histopathologic lesion characterization and identification of acid-fast bacilli (AFB), seeking to compare them. During slaughter of cattle in slaughter plants, under Federal Inspection Service in Sao Paulo State, were collected and identified, in duplicate, tissue samples with suggestive lesions of tuberculosis. One of the samples was intended for histopathology, being performed the hematoxylin-eosin (HE) staining for lesion characterization and the Ziehl-Neelsen (ZN) staining to identification the AFB. The other sample was separated to the molecular diagnosis, Polymerase Chain Reaction (PCR) and nested PCR. The bacterial DNA present in the lesion was extracted and the PCR was performed, showing 20.84% (10/48) of positive samples. However, when the results were compared with more sensitive tests (nested PCR) and cheapest ones (histopathologycal characterization of lesions and the AFB identification), different results were found. When performing nested PCR in negative samples by conventional PCR (38/48), it was found more 18.74% (9/38) of positive samples resulting in 39.58% (19/48) of positive samples by molecular diagnosis from tissue lesions. However, histopathological characterization by hematoxylin-eosin resulted in 66.67% (32/48) of positive samples and the identification of AFB by Ziehl-Neelsen, 54.17% (26/48) of positive samples for bovine tuberculosis. The molecular tissue diagnosis from lesions is possible, but it should not be the only method used for bovine tuberculosis diagnosis.

NILAI DIAGNOSTIK ANTIGEN TB DENGAN RAPID TEST DEVICE (TB AG) UNTUK TUBERKULOSIS PARU

In Indonesia, the diagnosis of pulmonary tuberculosis relies primarily on an identification of acid-fast bacilli on sputum smears. However, microscopic device has several limitations. The sensitivity of microscopic examination is variable. The quality of smear microscopic results is heavily depend on the workload, and the skill of the technician's reading the slide. TB antigen rapid test device (TB Ag) is fast, easy and does not either need skillness of the operator. The kit detects specific secreted antigen M.tuberculosis coded by: RD (Region of Difference) 1, RD2 and RD3. These RD1−3 were found deleted from BCG (Bacille Calmette-Guerine) vaccine strain. In the present study, the diagnostic value of TB Ag was assessed. Sputum samples were examined from 59 suspected tuberculosis patients and 22 non tuberculosis patients. The samples of the suspected tuberculosis patients were collected as three consecutive sputum specimens (spot, morning, spot). The total 199 specimens were examined by sputum smear microscopy and TB Ag. M.tuberculosis culture by using Lowenstein Jensen media, which was used as a gold standard. The sensitivity and specificity of microscopic sputum smear were 83.8% (95% CI: 70.0–89.4) and 96.3% (95% CI: 89.8–98.7), respectively. While, the sensitivity and specificity of TB Ag were 72.6% (95% CI: 63.9–79.9) and 90.9% (95% CI: 72.2–97.5), respectively. The concordance between microscopic sputum smear and TB Ag was 70.8%. TB Ag can be considered as a new diagnostic tool for the diagnosis of pulmonary tuberculosis, especially at the health services where there is no expert technician available for microscopic sputum smear examination.

An unusual cause of breast lump: isolated tuberculosis of the breast.

A 60-year-old woman presented with a painful lump of 4 months duration in her right breast. She denied any history of breast trauma or family history of breast cancer. Physical examination detected a firm, tender mass in the upper inner quadrant of her right breast without an associated sinus tract. Cytology from fine-needle aspiration of the swelling showed epithelioid cells, lymphohistocytic aggregates, and necrosis. Diagnosis was confirmed by the identification of acid-fast bacilli in tissue sections using Ziehl-Neelsen staining.

Clinical considerations on Buruli ulcer employing two molecular tests for the detection of Mycobacterium ulcerans in 100 skin biopsies

Buruli ulcer (BU) is an infected cutaneous lesion, the etiological agent of which is Mycobacterium ulcerans. Diagnosis is confirmed by the identification of acid-fast bacilli and culture. In clinically suspicious forms with negative bacteriological or Ziehl-Neelsen (ZN) findings, molecular tests are used. This study compared the concordance of nested polymerase chain reaction (PCR) (targeting IS2404) and PCR (targeting IS2606) in different clinical situations. A total of 57 samples were sourced from 39 BU patients. Control samples (n = 43) were obtained from non-BU ulcers in 38 patients. Samples were divided into two pieces and submitted to, respectively, histological examination and ZN staining, and PCR. Subsamples submitted to PCR were divided and submitted to nested PCR IS2404 and PCR IS2606, respectively. Of the 57 BU biopsies, positive results were obtained by nested PCR in 18 (31.6%) and by IS2606 PCR in 37 (64.9%) cases. Sequencing of the positive samples confirmed the specificity of amplicons in all nested PCR samples and in 26 of 37 (70.2%) samples positive to IS2606. Hence, nested PCR was more specific (100% vs. 93%) and less sensitive (32% vs. 46%) than IS2606 PCR. In the BU samples, nested PCR was negative in 15 instances, and IS2606 PCR was negative in 11 instances in which ZN histology had been positive (false negatives). Both PCRs were positive in six ZN-negative smears. We considered 57 samples from 39 BU patients in various clinical stages and at different times after the beginning of therapy. These provided positive results in 18 cases with IS2404 nested PCR and in 37 cases with PCR IS2606; only 26 of the latter remained positive subsequent to sequencing. Hence, even if IS2404 PCR is considered more specific, in subjects who appear to fail to respond to therapy, it is advisable to also carry out IS2606 PCR. A possible interpretation of the discordance between the two techniques due to unavoidable technical errors as well as to different sensitivity of the two tests at M. ulcerans DNA low concentration (i.e. in recent infection and in well-treated cases) is discussed.

Aquarium-borne Mycobacterium marinum skin infection. Report of 15 cases and review of the literature

Mycobacterium marinum is a non-tuberculous photochromogenic mycobacterium, commonly responsible for fish and amphibious infections world-wide. Contagion in humans typically follows minor hand trauma from aquarium keeping and manifests as a granulomatous infection of the skin. Dissemination is rare and almost exclusive to immunosuppressed hosts. 15 cases of M. marinum fish tank related infection are hereby reported. The site of infection was the upper limbs in all cases. 3 patients presented a single papulo-verrucous lesion, while the remaining 12 showed a sporotrichoid clinical pattern. Diagnosis was reached by history and clinical examination and further supported by one or more of the following criteria: histology, culture, acid fast bacilli identification from histologic specimen and PCR. 2 to 3 months minocycline treatment showed efficacy in 13 individuals, another case was treated with rifampicin-isoniazid association, yet another showed spontaneous regression over a 3 month period.

Usefulness of Interferon-Gamma Release Assay for Diagnosis of Tuberculous Fistulae in Ano

Purpose: Interferon gamma release assays (QuantiFERON-TB Gold in Tube test [QFT-GIT]); Cellestis Limited, Victoria, Australia) have been studied for diagnosing pulmonary tuberculosis (TB) or latent TB but there have been no reports on the usefulness of this assay in diagnosing tuberculous anal fistula in actual clinical practices. In this study, we evaluated its diagnostic usefulness in patients with suspected tuberculous anal fistula. Methods: We conducted a retrospective analysis of 119 patients with suspected tuberculous anorectal fistula from May 2007 to May 2009. Diagnosis of tuberculous fistula was concluded by identification of acid-fast bacilli, typical caseating granuloma and successful clinical response to anti-TB chemotherapy. All patients underwent the QFT-GIT and all patients diagnosed with tuberculous anal fistula were analyzed. Results: Of the 119 patients with suspected TB fistula, 51 (43%) patients were classified as having TB fistula, including 31 with confirmed tuberculosis and 20 with probable tuberculosis, and other 68 (57%) were classified as not having tuberculosis. Among the 51 patients with TB fistula, Chronic caseating granuloma, acid-fast bacilli stain, and successful clinical response to anti-TB treatment were positive in 27 (52.9%), 4 (7.8%), and 20 (39.2%), respectively. Of the 51 with TB fistula, 44 had positive QFT-GIT results and 7 had negative results. The sensitivity and specificity of the assay were 86% and 85%, and positive predictive value (PPV) and negative predictive value (NPV) were 81% and 89%, respectively. Conclusion: QFT-GIT is a simple, sensitive, and specific method for the diagnosis of clinically highly suspected TB fistula.

Identification of acid-fast bacilli using pyrosequencing analysis

Pyrosequence identification of 117 isolates of acid-fast bacilli (AFB) was compared to both routine phenotypic methods and Sanger sequencing. Two (2) vendor-provided pyrosequencing primers specific for AFB were used for the study. Pyrosequence analysis correctly identified 114 (98%) of the tested 117 AFB isolates. Among the test Mycobacterium spp., 18 of 20 Mycobacterium spp. were identified correctly to the species level. All rapidly growing mycobacteria were correctly identified to species by pyrosequencing. Other slowly growing mycobacteria such as Mycobacterium tuberculosis, Mycobacterium kansasii, Mycobacterium avium– intracellulare, and others were easily identified by pyrosequencing. Only Mycobacterium simiae and Mycobacterium scrofulaceum were not identifiable by the pyrosequence method. Among the 25 Nocardia isolates, all were correctly identified to the genus level. Identification of AFB by pyrosequence analysis provides both a rapid and accurate method for this group of organisms.

Granulomas in acquired immunodeficiency syndrome‐associated cutaneous Kaposi sarcoma: evidence for a role for Mycobacterium tuberculosis

Co-lesional acquired immunodeficiency syndrome-associated cutaneous Kaposi sarcoma (AIDS-KS) and Mycobacterium tuberculosis-associated granulomatous inflammation are undocumented. Retrospective appraisal of skin biopsies with co-lesional AIDS-KS and microscopic tuberculosis (TB). Sixteen biopsies from nine males and seven females form the study cohort. Histological assessment confirmed nodular and plaque KS in 12 and 4 cases each, respectively. Necrotizing, non-necrotizing and a combination of necrotizing and non-necrotizing granulomatous inflammation were present in nine, two and five biopsies each, respectively. The identification of acid fast bacilli on Ziehl-Neelsen staining and M. tuberculosis on polymerase chain reaction confirmed co-lesional TB in 15/16 biopsies. Co-lesional AIDS-KS and lichen scrofulosorum, hitherto undocumented, were confirmed in one biopsy. The histopathological findings served as a marker of human immunodeficiency virus (HIV) infection, visceral TB, therapeutic noncompliance and multidrug resistant pulmonary TB in nine, eight, five and one patient, respectively. M. tuberculosis was cultured from sputum or nodal tissue of all patients. Granulomatous inflammation in KS requires optimal histopathological and molecular investigation to confirm an M. tuberculosis origin. The cutaneous co-lesional occurrence of AIDS-KS and microscopic TB may serve as the sentinel clue to HIV infection, systemic TB, therapeutic noncompliance or multidrug resistant TB.

Usefulness of the Paralens™ Fluorescent Microscope Adaptor for the Identification of Mycobacteria in Both Field and Laboratory Settings

The presence of acid-fast bacilli (AFB) in laboratories has traditionally been demonstrated using the fluorochrome method, which requires a fluorescent microscope or the Ziehl-Neelsen (ZN) method employing light microscopy. Low sensitivity of the ZN method and high costs of fluoroscopy make the need for a more effective means of diagnosis a top priority, especially in developing countries where the burden of tuberculosis is high. The QBC ParaLens™ attachment (QBC Diagnostic Inc., Port Matilda, PA) is a substitute for conventional fluoroscopy in the identification of AFB. To evaluate the efficacy of the ParaLens LED (light-emitting diode) system, the authors performed a two-part study, looking at usefulness, functionality and durability in urban/rural health clinics around the world, as well as in a controlled state public health laboratory setting. In the field, the ParaLens was durable and functioned well with various power sources and lighting conditions. Results from the state laboratory indicated agreement between standard fluorescent microscopy and fluorescent microscopy using the ParaLens. This adaptor is a welcome addition to laboratories in resource-limited settings as a useful alternative to conventional fluoroscopy for detection of mycobacterial species.

IgM and IgG Antibodies in Tuberculosis

Introduction: The diagnosis of tuberculosis relies on the identification of acid-fast bacilli on unprocessed sputum smears using conventional light microscopy. Microscopy has high specificity in tuberculosis-endemic countries, but modest sensitivity which varies among laboratories (range 20% to 80%). Moreover, the sensitivity is poor for paucibacillary disease (e.g., pediatric and HIVassociated tuberculosis). Many supportive investigations including serolological tests being utilized for tuberculosis diagnosis have wide variations in sensitivity, specificity in different studies. The aim of study was to evaluate the recombinant 38 KDa antigen from M. tuberculosis - based Enzyme Immunoassays (EIA) test for its sensitivity, specificity and other statistical parameters. Methods: This hospital based prospective cross-sectional study was conducted at Tribhuvan University Teaching Hospital, Kathmandu, from April 28, 2009 to November 30,2009. Sera from total 90 patients, pulmonary tuberculosis, extrapulmonary tuberculosis and non-tubercular chest infection patients who did not have past TB or exposure history , 30 in each group were used for Pathozyme Myco kit evalution to determine the IgM and IgG antibodies activity against the recombinant 38 KDa antigen of Mycobacteria Results: In overall tuberculosis, IgM TB had sensitivity 48.3%,specificity 76.7%, positive predictive value 80.6% which was statistically significant(p=0.025) . The IgG TB had sensitivity 66.7%,specificity 83.3%,positive predictive value 88.9% which is statistically highly significant(p<0.001) to diagnose tuberculosis. Utilizing IgM and IgG both together, sensitivity decreased to 44.3%, but specificity increased to 90.0% and positive predictive value 88.5%, which was statistically significant (p=0.006) for the diagnosis of tuberculosis. Conclusions: IgG TB antibody has high sensitivity and specificity for tuberculosis diagnosis, but IgM antibody should also be evaluated along with IgG antibody to increase specificity. Keywords: Extrapulmonary tuberculosis (EPTB), 38 kDa antigen, IgM, IgG TB antibody, Pathozyme-Myco, Pulmonary tuberculosis (PTB). DOI: 10.3126/joim.v31i3.2995 Journal of Institute of Medicine, December, 2009; 31(3) 34-40

Comparison of the modified fluorescent method and conventional Ziehl–Neelsen method in the detection of acidfast bacilli in lymphnode aspirates

Objectives:The objectives were to correlate the modified fluorescent method with the conventional Ziehl–Neelsen (ZN) method for the detection of acid-fast bacilli (AFB) and, also to study the efficacy and advantages of using the auramine–rhodamine stain on lymph node aspirates under fluorescent microscopy.Methods:In 108 consecutive patients with a clinical suspicion of tuberculosis (TB) presenting with lymphadenopathy, fine needle aspirations were performed. Smears from the aspirates were processed for routine cytology, the conventional ZN method, and the modified fluorescent method. The significance of the modified fluorescent method over the conventional ZN method was analyzed using the chi-square test.Results:Out of 108 aspirates, 102 were studied and remaining 6 were excluded from the study due to diagnosis of malignancy in 4.04% (4/6) and inadequate aspiration in 2.02% (2/6). Among the 102 aspirates, 44.11% (45/102) were positive for AFB on the conventional ZN method, 58.9% (60/102) were indicative of TB on cytology, while the smear positive increased to 81.37% (83/102) on the modified fluorescent method.Conclusions:Fluorescent microscopy has the advantage of speed and ease of screening, and reduces observer fatigue. The modified fluorescent method was found to be more advantageous than routine cytology and conventional ZN method, particularly in paucibacillary cases. The bacillary positivity rates were higher in the modified fluorescent method than in the ZN method. Hence, the modified fluorescent method can be an adjuvant when used with routine cytology for the identification of AFB.

An update on lower urinary tract tuberculosis

Tuberculosis of the genitourinary tract presents with atypical manifestations. Only 20% to 30% of patients with genitourinary tuberculosis have a history of pulmonary infection. Tuberculosis often affects the lower genitourinary system rather than the kidney. Tuberculosis of the lower genitourinary tract most commonly affects the epididymis and the testis, followed by bladder, ureter, prostate, and penis. Use of bacillus Calmette-Guérin therapy for bladder cancer can cause symptomatic tubercular infections of the lower genitourinary tract. Tuberculosis of the lower genitourinary tract can present with irritative voiding symptoms, hematuria, epididymo-orchitis, prostatitis, and fistulas. Tuberculosis of the seminal vesicles, vas, fallopian tubes, and the uterus can cause infertility. Urinalysis may demonstrate sterile pyuria, hematuria, or albuminuria. Identification of acid-fast bacilli in culture or tissue or by polymerase chain reaction studies is diagnostic. Medical treatment may not result in resolution of symptoms. Surgical intervention and reconstruction of the urinary tract are frequently indicated.

Commercial Serological Antibody Detection Tests for the Diagnosis of Pulmonary Tuberculosis: A Systematic Review

BackgroundThe global tuberculosis epidemic results in nearly 2 million deaths and 9 million new cases of the disease a year. The vast majority of tuberculosis patients live in developing countries, where the diagnosis of tuberculosis relies on the identification of acid-fast bacilli on unprocessed sputum smears using conventional light microscopy. Microscopy has high specificity in tuberculosis-endemic countries, but modest sensitivity which varies among laboratories (range 20% to 80%). Moreover, the sensitivity is poor for paucibacillary disease (e.g., pediatric and HIV-associated tuberculosis). Thus, the development of rapid and accurate new diagnostic tools is imperative. Immune-based tests are potentially suitable for use in low-income countries as some test formats can be performed at the point of care without laboratory equipment. Currently, dozens of distinct commercial antibody detection tests are sold in developing countries. The question is “do they work?”Methods and FindingsWe conducted a systematic review to assess the accuracy of commercial antibody detection tests for the diagnosis of pulmonary tuberculosis. Studies from all countries using culture and/or microscopy smear for confirmation of pulmonary tuberculosis were eligible. Studies with fewer than 50 participants (25 patients and 25 control participants) were excluded. In a comprehensive search, we identified 68 studies. The results demonstrate that (1) overall, commercial tests vary widely in performance; (2) sensitivity is higher in smear-positive than smear-negative samples; (3) in studies of smear-positive patients, Anda-TB IgG by enzyme-linked immunosorbent assay shows limited sensitivity (range 63% to 85%) and inconsistent specificity (range 73% to 100%); (4) specificity is higher in healthy volunteers than in patients in whom tuberculosis disease is initially suspected and subsequently ruled out; and (5) there are insufficient data to determine the accuracy of most commercial tests in smear microscopy–negative patients, as well as their performance in children or persons with HIV infection.ConclusionsNone of the commercial tests evaluated perform well enough to replace sputum smear microscopy. Thus, these tests have little or no role in the diagnosis of pulmonary tuberculosis. Lack of methodological rigor in these studies was identified as a concern. It will be important to review the basic science literature evaluating serological tests for the diagnosis of pulmonary tuberculosis to determine whether useful antigens have been described but their potential has not been fully exploited. Activities leading to the discovery of new antigens with immunodiagnostic potential need to be intensified.

CONCURRENT WEST NILE VIRUS AND MYCOBACTERIUM AVIUM INFECTION IN A BLACK-NECKED SWAN (CYGNUS MELANOCORYPHUS)

An adult male black-necked swan (Cygnus melanocoryphus) was evaluated for a routine physical examination and West Nile virus vaccination. Nine days later, the swan was hospitalized for weakness, dehydration, tremors, and leukocytosis. Gradual clinical improvement was seen over a 2-wk course of supportive care. However, the animal became acutely weak and was found dead. Histopathology revealed severe granulomatous pneumonia and air sacculitis with dissemination to the liver, spleen, intestine, and coelom. Mycobacterial infection was confirmed by identification of acid-fast bacilli within tissue sections and by polymerase chain reaction. Concurrent West Nile virus infection was identified in sections of brain by using immunohistochemistry.