Mycobacterial Culture Results Research Articles

Evaluation of the SD Bioline TB Ag MPT64 test for identification of Mycobacterium tuberculosis complex from liquid cultures in Southwestern Uganda.

BackgroundTo confirm presence of Mycobacterium tuberculosis complex, some tuberculosis culture laboratories still rely on para-nitrobenzoic acid (PNB), a traditional technique that requires sub-culturing of clinical isolates and two to three weeks to give results. Rapid identification tests have improved turnaround times for mycobacterial culture results. Considering the challenges of the PNB method, we assessed the performance of the SD Bioline TB Ag MPT64 assay by using PNB as gold standard to detect M. tuberculosis complex from acid-fast bacilli (AFB) positive cultures.ObjectivesThe aim of this study was to determine the sensitivity, specificity and turnaround time of the SD MPT64 assay for identification of M. tuberculosis complex, in a setting with high prevalence of tuberculosis and HIV.MethodsA convenience sample of 690 patients, with tuberculosis symptoms, was enrolled at Epicentre Mbarara Research Centre between April 2010 and June 2011. The samples were decontaminated using NALC-NaOH and re-suspended sediments inoculated in Mycobacterium Growth Indicator Tubes (MGIT) media, then incubated at 37 °C for a maximum of eight weeks. A random sample of 50 known negative cultures and 50 non-tuberculous mycobacteria isolates were tested for specificity, while sensitivity was based on AFB positivity. The time required from positive culture to reporting of results was also assessed with PNB used as the gold standard.ResultsOf the 138 cultures that were AFB-positive, the sensitivity of the SD MPT64 assay was 100.0% [95% CI: 97.3 – 100] and specificity was 100.0% (95% CI, 96.4 – 100). The median time from a specimen receipt to confirmation of strain was 10 days [IQR: 8–12] with SD MPT64 and 24 days [IQR: 22–26] with PNB.ConclusionThe SD MPT64 assay is comparable to PNB for identification of M. tuberculosis complex and reduces the time to detection.

26-Year-Old Man With Nausea, Delirium, and Fever

Resident in Internal Medicine, Mayo School of Graduate Medical Education, Rochester, MN (H.L.T.); Advisor to resident and Consultant in Infectious Diseases, Mayo Clinic, Rochester, MN (L.M.B.). A 26-year-old-man who had been living in Indonesia until 4 months previously presented to our hospital for evaluation of fever, agitation, and altered mental status. He had been seen previously at another facility for vague abdominal pain, nausea, and fever. He had become subacutely agitated and was transferred to our institution because of altered mental status and vomiting. On admission, he was febrile (temperature, 39.3 C) and tachycardic (heart rate, 118 beats/ min); his blood pressure was 134/96 mm Hg, and his oxygen saturation was 100% while breathing room air. Physical examination findings were notable for intermittent altered mental status with restlessness, agitation, inattention, and pain with neck flexion and posterior neck palpation. Findings on work-up at the outside facility included a sodium level of 118 mmol/L and no abnormalities detected on head computed tomography (CT) and chest radiography. His pupils were mildly constricted but responded to light. Admission laboratory studies yielded a normal white blood cell count of 10.1 10/L and an improved sodium concentration of 133 mmol/L.

A descriptive analysis of nontuberculous mycobacterial infections (NTM) of the upper extremity

ObjectivesNontuberculous mycobacterial (NTM) infections are frequently reported as a cause of bone and soft-tissue infection of the upper extremity, primarily in the hand and wrist. Limited information exists on clinical characteristics and treatment outcomes of patients with NTM infection of the upper extremity. The clinical and radiological characteristic of these infections in a large group of patients with upper extremity NTM infections are described herein. MethodsA retrospective analysis was conducted of NTM infections of the upper extremity at Mayo Clinic Florida from December 2000 through December 2012. Only patients with positive mycobacterial cultures from the upper extremities were included. Data collection included demographics, radiologic and clinical characteristics, mycobacterial culture results, time to diagnosis and treatment outcomes. ResultsForty-two patients were included; 71% were male and the mean age was 60±18years. Eighteen (43%) patients were diagnosed with skin/soft tissue infections and 15 (36%) had tenosynovitis. Twenty-six (62%) patients were immunosuppressed. The most common underlying medical conditions were rheumatologic disorders (40%) and diabetes mellitus (17%). Sixteen (38%) patients were taking glucocorticosteroids, and 11 (26%) patients were receiving tumor necrosis factor alpha (TNF-α) inhibitors at the time of diagnosis. Injuries to the affected extremity were reported in 62% of patients. Fishing (21%) and gardening (14%) were the most common reported exposures. Signs and symptoms of infection were localized to the skin in 62% and extended to the joints in 52%.Mycobacterium marinum (36%) and Mycobacterium chelonae/abscessus (33%) were the two most commonly identified organisms. Radiologic studies were available in 30 (71%) patients.Average time to clinical evaluation from onset of symptoms was 2.6 (±3.5) months and time to diagnosis from initial clinical evaluation was 4.5 (±4.5) months. Forty-one (98%) patients were treated. Twenty-eight (68%) patients were treated with both antimicrobial and surgical debridement, nine (21%) with antimicrobial treatment alone, and four (10%) with surgical debridement alone. Twenty-six (62%) patients were cured, four (9%) relapsed after the first round of treatment, two (5%) failed all treatment modalities, and three (7%) patients died. ConclusionDiagnosis of NTM infection of the upper extremity is often delayed due to its indolent presentation and lack of clinical suspicion. Healthcare professionals should be aware of the increasing incidence of soft tissue NTM infection after percutaneous injury, especially in immunosuppressed patients, to improve diagnostic promptness and treatment outcome.

Is routine bronchoscopic culture indicated in areas with low tuberculosis prevalence?

Tertiary care university-affiliated medical centre. To determine the value of routine culture of bronchoscopy samples for mycobacteria even when tuberculosis (TB) is not strongly suspected in low TB prevalence areas. A prospective study of 362 consecutive patients who underwent a bronchoscopy procedure. All demographic, clinical and computed tomography findings, and bacterial and mycobacterial culture results were collected. A total of 217 men and 145 women, with a mean age of 63 ± 15 years, were included in the study. All underwent bronchoscopy with routine culture for TB. Ten cultures (2.8%) grew mycobacteria: 2 (0.55%) Mycobacterium tuberculosis and 8 (2.2%) non-tuberculous mycobacteria (NTM). The NTM included M. avium complex (MAC) in six patients and M. simiae in two patients. Two patients had two different mycobacteria species: 1 patient with M. simiae and MAC and the other with TB and MAC. All eight patients were negative for microscopy. Based on our results, we suggest that routine culture of bronchial specimens for TB is not indicated in patients with a low clinical suspicion of active TB in countries with a low TB burden.

VIPoma in a 37-year-old man

In September, 2011, a 37-year-old man with a past history of pulmonary tuberculosis came to our hospital with persistent watery diarrhoea, weight loss, and hypokalaemia of 2 years’ duration. The diarrhoea did not stop with fasting, and serum potassium had remained at 2∙5 mmol/L despite multiple cycles of intravenous potassium replacement. Physical examination and routine blood investigations were normal, as were both upper and lower gastrointestinal tract endoscopies. An abdominal CT showed a 5∙9 × 3∙4 cm lesion in the pancreatic tail and a solitary hepatic metastasis, confi rmed by MRI (fi gure). However, in view of the patient’s past history of tuberculosis, the medical team waited for mycobacterial culture results before making a diagnosis of probable stage IV pancreatic adeno carcinoma. Meanwhile, an endocrine referral was made to address the hypokalaemia. The patient’s signs and symptoms made the clinical team consider the extremely rare diagnosis of a vasoactive intestinal peptide endocrine tumour— VIPoma, also known as Verner-Morrison syndrome. We requested serum chromogranin A and 24-h urinary 5-hydoxyindoleacetic acid, which were both negative. The news of Steve Jobs’s death from a neuroendocrine tumour, which occurred around this time, prompted the clinical team to reconsider this diagnosis despite initial negative results. Endoscopic ultrasound-guided pancreatic tail biopsy was therefore done next, and immunohistochemistry of the tumour tissue stained positive for cytokeratin AE1/3, synaptophysin, and chromo granin. Blood samples were taken for vasoactive intestinal peptide ELISA assay, before a trial of octreotide was initiated. His diarrhoea resolved within 3 days, accompanied by the resolution of hypokalaemia. The plasma vasoactive intestinal peptide was 175 pmol/L (normal 3 cm in diameter. About 75% occur in the pancreatic tail, and 60–80% are already metastasised at diagnosis. Being slow growing, VIPomas are generally compatible with long survival of 5–10 years. Most adult patients are diagnosed between 30–50 years of age. High volume secretory diarrhoea (>700 mL/day) that persists with fasting is virtually universal. Hypo kalaemia occurs in 70–100% of patients. Investigations include serum vasoactive intestinal peptide, pancreatic polypeptide, and chromogranin A. Functional PET imaging such as 68-Ga DOTA fusion PET/CT scans have sensitivity of about 97%, compared with about 80% in CT scans, and 85% in MRIs. This higher accuracy facilitates much earlier detection of metastases. When used therapeutically, peptide receptor radionuclide therapy was reported in one case report to reduce widespread metastatic disease down to a single liver metastasis at 1-year follow-up. A limitation of peptide receptor radionuclide therapy is the potential lack of somatostatin receptor expression by the tumour. In such cases, sunitinib and everolimus (both in phase III trials) are among the most promising alternatives to traditional hepatic-directed therapies including resection, ablation, hepatic artery embolisation, and liver transplantation. Surgery remains the defi nitive treatment for VIPoma. Octreotide is useful in suppressing VIP secretion, and interferon-alpha and glucocorticoids are sometimes used in refractory cases to improve symptoms of hormonal secretion.

Short-Term Storage Does Not Affect the Quantitative Yield of Mycobacterium tuberculosis in Sputum in Early-Bactericidal-Activity Studies

Early-bactericidal-activity (EBA) studies measure the change in mycobacterial load in sputum over time to evaluate antituberculosis drugs. We investigated whether a delay in sputum processing influences the quantitative results of sputum mycobacterial culture. We identified pretreatment smear-positive sputum samples collected overnight and processed at a single laboratory. Sputum volume, time from sputum collection to processing, CFU counts/ml of sputum, and time to culture positivity (TTP) data were retrieved. We obtained 817 TTP and 794 CFU results from a total of 844 sputum samples. Contamination did not occur more frequently with prolonged storage (TTP, 2.0%; CFU, 2.4%). Sample volumes were <5 ml in 5%, 5 to 10 ml in 46%, and >10 ml in 49%. Delays to processing were 0, 1, 2, and 3 days in 696 (43.2%), 722 (44.8%), 128 (7.9%), and 65 (4.0%) samples, respectively. TTP and CFU did not significantly differ between days of delay to processing (P = 0.098 and P = 0.908, respectively), but there was a nonsignificant trend toward a prolonged TTP over time (P = 0.052, Jonckheere-Terpstra trend test). Sputa of <5 ml in volume showed a significantly prolonged TTP compared to sputum of >5 ml (113 h versus 99 h; P < 0.01) but no significant decrease in CFU. Sputum can be stored under refrigerated conditions for deferred processing for at least 3 days. This means that central laboratories can be used for quantitative mycobacterial study endpoints when delays to processing are not expected to exceed a few days. Care should be taken to collect sputum of sufficient volume.

An Evaluation of MAPIA in Michigan as an Ante-Mortem Supplemental Test for Use in Suspect Tuberculosis Cattle

The objective of this study was to make use of bovine tuberculosis suspect cattle from the state of Michigan to validate a multiantigen print immunoassay for use on sera to serve as an improved supplementary ante-mortem test to increase specificity of current tuberculosis testing methods. Over a 27-month period, 234 sera were collected and tested by MAPIA method, which was evaluated using four different interpretation criteria. These results were subsequently compared to final mycobacterial culture and PCR results obtained by the National Veterinary Services Laboratories, Ames, IA, which served as the true indicator of the cattle's tuberculosis infection status. This study indicates that an interpretation criterion which includes 3 or more positive reactions to the 11 different mycobacteria antigens utilized provided both an acceptable sensitivity (69.39%) and a high specificity (90.27%). This MAPIA technique shows potential for eventual application as a supplementary ante-mortem tuberculosis serologic test following one of the various current or soon-to-be-approved whole herd screening assays as part of a tuberculosis eradication program.

The frequency and potential clinical impact of non-analytical errors in the RCPA Microbiology QAP 1987-2008

Reliable reporting of laboratory results is an important component in the diagnosis and management of infectious diseases. We investigated the frequency of pre- and post-analytical errors by participants in the Royal College of Pathologists of Australasia (RCPA) Microbiology Quality Assurance Program (MQAP). We retrospectively reviewed MQAP data 1987-1991 and 2004-2008. Pre-analytical error rates were based on participants' detection rate of clerical error for patient name and identification number for the given test item. Fictitious errors were defined as the reporting of a labelling error when in fact there was no discrepancy. Post-analytical error rates were based on clear transcription errors resulting in the test result being incorrectly assigned to another test item. When there was one clerical error 10.6% of participants failed to report it. When there were two errors 5.3% failed to report either error and 8.8% only reported one error. Fictitious errors were reported by 1.1% of participants. Pre-analytical errors have not decreased over time. Of the 106 items where direct transposition errors were possible, 73 (69%) had at least one participant who transposed the results. During 2004-2008 transposition of mycobacterial smear and culture results occurred in 18% and 16% of participants, respectively. Pre- and post-analytical errors are not rare amongst participants in the RCPA MQAP. These non-analytical components of the testing pathway require improvement because of their potential to adversely affect patient care.

Comparison of Sampling Methods, Culture, Acid-fast Stain, and Polymerase Chain Reaction Assay for the Diagnosis of Mycobacteriosis in Ring-neck Doves (Streptopelia risoria)

Even when different diagnostic modalities are available, mycobacteriosis is difficult to diagnose in a live bird. To investigate the diagnostic value of sampling different tissues and using different diagnostic methods, we evaluated results of mycobacterial culture, Ziehl-Neelsen (ZN) staining, and single-amplification polymerase chain reaction assay (PCR) of 18 ring-neck doves (Streptopelia risoria) with confirmed natural infection with Mycobacterium avium avium. Results of testing liver biopsy, duodenal aspirate, and bone marrow aspirate samples and liver and spleen samples collected at necropsy were compared. Results showed the use of one single technique did not allow identification of all infected birds. In liver biopsy and bone marrow aspirate samples, culture had the highest sensitivity, whereas PCR assay and ZN staining had low sensitivity, and their combination was less sensitive than culture alone. Examination of ZN staining of the intestinal aspirate samples failed to detect infection in most birds. More splenic lesions contained acid-fast organisms than did liver lesions, suggesting that splenic biopsy may have the greatest potential for diagnosis of mycobacterial infection antemortem. Sensitivity was higher for postmortem examination of multiple liver sections than of a single biopsy section; therefore, obtaining multiple liver biopsy sections may increase detection of mycobacteria. Examination of multiple tissues and the use of several different diagnostic techniques significantly increases the probability of diagnosis of mycobacteriosis.

Pleural tuberculosis: an update

Pleural tuberculosis accounts for fewer than 1% of all exudative effusions in western countries, occurring in only 3-5% of tuberculous patients. However, in developing countries like India, it is responsible for 30-80% of all pleural effusions encountered and may complicate tuberculosis in 31% of all cases. Thus, tuberculous pleuritis remains a major contributor to global morbidity and mortality. Tuberculous pleurisy presents a diagnostic and therapeutic problem due to the low sensitivity of the diagnostic tools. There have been many advances in the field that we have attempted to update. Due to the limitations of conventional tests and the delay of several weeks for mycobacterial culture results, there has been a resurgence of interest in newer rapid tests and biomarkers. This review highlights the deficiencies of the traditional tests, while providing an overview of the newer tests. In addition, we provide an update on the changing epidemiology, clinical features and current treatment options. Newer immunological tests and scoring systems will revolutionize the way tuberculous pleurisy is diagnosed in the years ahead. Future research needs include validating the available diagnostic tests in larger randomized studies, finding newer specific biomarkers that are simple, accurate and cost-effective for the developing world and determining treatment regimens specific for tuberculous pleurisy.

Predicting results of mycobacterial culture on sputum smear reversion after anti-tuberculous treatment: a case control study

BackgroundLittle is currently known regarding sputum smear reversion (acid-fast smear becomes positive again after negative conversion) during anti-tuberculous treatment. This study aimed to evaluate its occurrence in patients with pulmonary tuberculosis (TB) and identify factors predicting results of mycobacterial culture for smear-reversion of sputum samples.MethodsThe retrospective review was performed in a tertiary referral center and a local teaching hospital in Taiwan. From 2000 to 2007, patients with smear-positive culture-confirmed pulmonary TB experiencing smear reversion after 14 days of anti-tuberculous treatment were identified.ResultsThe 739 patients with smear-positive pulmonary TB had 74 (10%) episodes of sputum smear reversion that grew Mycobacterium tuberculosis in 22 (30%) (Mtb group). The remaining 52 episodes of culture-negative sputum samples were classified as the non-Mtb group. The anti-tuberculous regimen was modified after confirming smear reversion in 15 (20%). Fourteen episodes in the Mtb group and 15 in the non-Mtb group occurred during hospitalization. All were admitted to the negative-pressure rooms at the time of smear reversion. Statistical analysis showed that any TB drug resistance, smear reversion within the first two months of treatment or before culture conversion, and the absence of radiographic improvement before smear reversion were associated with the Mtb group. None of the smear reversion was due to viable M. tuberculosis if none of the four factors were present.ConclusionsSputum smear reversion develops in 10% of patients with smear-positive pulmonary TB, with 30% due to viable M. tuberculosis bacilli. Isolation and regimen modification may not be necessary for all drug-susceptible patients who already have radiographic improvement and develop smear reversion after two months of treatment or after sputum culture conversion.

Comparison of Various Detection Methods of Mycobacterium Species in Formalin-Fixed Paraffin-Embedded Tissue with Chronic Granulomatous Inflammation

BACKGROUNDTo determine the most effective method for detecting mycobacteria in formalin- fixed paraffin-embedded (FFPE) tissue, we compared the results of Ziehl-Neelsen stain (ZNS) and mycobacterial culture with those of polymerase chain reaction (PCR) and real-time quantitative PCR (RQ-PCR).METHODSWe analyzed 54 cases diagnosed as chronic granulomatous inflammation. In all cases, ZNS and nested PCR using three different primers, IS6110, Mpb64 and IS6110/Rpobeta were done. RQ-PCR with the IS6110/Rpobeta primer was done in 51 cases.RESULTSMycobacteria were identified by ZNS in 15/54 (27.8%) cases. RQ-PCR had the highest sensitivity (80.0%) compared to PCR with IS6110 (73.3%), Mpb64 (60.0%) and IS6110/Rpobeta (73.3%). Specificity was higher in all PCR experiments (79.5-82.1%) than in RQ-PCR (69.4%) experiments. The false negative rate was lowest for RQ-PCR (20.0%) than for PCR with IS6110 (26.7%), Mpb64 (40.0%) and IS6110/Rpobeta (26.7%). The false positive rate was highest for RQ-PCR (30.6%) compared to PCR with IS6110 (20.5%), Mpb64 (17.9%) and IS6110/Rpobeta (20.5%).CONCLUSIONSRQ-PCR had the highest sensitivity, and the lowest false negative rate, but it also had a higher false positive rate than PCR for detection of mycobacteria in FFPE tissues.

Culture result of smear-positive sputum samples after 2 months of antituberculous treatment

To the Editors: The correlation between sputum smear for acid-fast bacilli (AFB) and culture for Mycobacterium tuberculosis is usually good before antituberculous treatment (ATT), but it is not so good after treatment has started. In previous studies, up to 23.5% of patients had sputum that remained smear positive after 2 months of ATT 1. Old age, high bacillary load, presence of pulmonary cavitary lesions, treatment interruption and emergence of resistant strains are risk factors of persistent smear positivity. Determining whether these sputum samples contain viable tuberculosis (TB) bacilli is crucial because it indicates higher rates of relapse 2, 3. Meanwhile, for patients without viable TB bacilli, modifying treatment regimens and isolation appears to be redundant. However, the results of mycobacterial culture are only available after 2 weeks, even when using fluorometric liquid culture technique. Despite having good sensitivity and specificity, commercialised nucleic acid amplification tests are expensive and do not discriminate between viable and dead bacilli and, therefore, are not recommended for TB patients receiving ATT. Thus, we conducted a study to identify clinical factors for predicting the culture results of the persistent smear-positive sputum samples in a 2,100 bed, tertiary-care referral centre in northern Taiwan and an 800 bed local teaching hospital in southern Taiwan. In the two hospitals, all sputum specimens were processed by adding NaOH-citrate- N -acetyl-l-cysteine at room temperature for 15 min. After centrifugation, the precipitate was resuspended 4. Before October 2006, smears for AFB of the processed samples were stained using the Kinyoun method. From November 2006, the smear was stained with auramine-rhodamine fluorochrome 5. Smears were graded according to guidelines established by the American Thoracic Society 6 and the highest smear grading was recorded. All collected …

Direct real-time PCR examination for Mycobacterium tuberculosis in respiratory samples can be cost effective

Aim: To assess whether the use of direct realtime polymerase chain reaction (PCR) on smear-positive sputa can be cost-effective, by speciating mycobacteria earlier than current methods and thereby preventing unnecessary screening tests as part of the contact tracing process. Methods: A retrospective study of all patients with smear-positive sputa in a Liverpool teaching hospital between 2004 and 2007. All the PCRs performed on these patients were reviewed and compared them with their mycobacterial culture results. Unit costs for PCR, chest X-ray (CXR), tuberculin skin test (TST), interferon-gamma (IFN-γ) and medical/nursing time were conservatively estimated at £50, £11, £10, £40 and £30 respectively. The total PCR costs were compared with the costs of unnecessary follow up of patients, negative for Mycobacterium tuberculosis (MTB) by PCR, subsequently confirmed to be MTB culture negative. Results: 203 smear-positive patients underwent direct PCR testing. 126 (62%) patients grew Mycobacterium tuberculosis (MTB), 74 (37%) had environmental mycobacterial infection (EMI) and 3 (1%) were culture negative. Of the 126 patients’ culture positive MTB patients, 123 were PCR positive and 3 PCR negative. Of the 77 patients that were culture negative for MTB, 75 were PCR negative and 2 PCR positive The sensitivity, specificity, positive and negative predictive values for direct PCR versus MTB culture were 98%, 96%, 98% and 97% respectively. Total costs of all PCRs performed amounted to £10,150. The cost of contact procedures for PCR-negative and MTB culturenegative index cases was estimated at £19,650. This equated to a total saving of £9,500 in contact tracing costs. Conclusions: Direct PCR examination testing of smear-positive patients can be cost-effective in areas where there is a high incidence of EMI.

EVALUATION OF BLOOD ASSAYS FOR DETECTION OF MYCOBACTERIUM BOVIS IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) IN MICHIGAN

Surveillance and control activities related to bovine tuberculosis (TB) in free-ranging, Michigan white-tailed deer (Odocoileus virginianus) have been underway for over a decade, with significant progress. However, foci of higher TB prevalence on private lands and limited agency ability to eliminate them using broad control strategies have led to development and trial of new control strategies, such as live trapping, testing, and culling or release. Such strategies require a prompt, accurate live animal test, which has thus far been lacking. We report here the ability of seven candidate blood assays to determine the TB infection status of Michigan deer. Our aims were twofold: to characterize the accuracy of the tests using field-collected samples and to evaluate the feasibility of the tests for use in a test-and-cull strategy. Samples were collected from 760 deer obtained via five different surveys conducted between 2004 and 2007. Blood samples were subjected to one or more of the candidate blood assays and evaluated against the results of mycobacterial culture of the cranial lymph nodes. Sensitivities of the tests ranged from 46% to 68%, whereas specificities and negative predictive values were all >92%. Positive predictive values were highly variable. An exploratory analysis of associations among several host and sampling-related factors and the agreement between blood assay and culture results suggested these assays were minimally affected. This study demonstrated the capabilities and limitations of several available blood tests for Mycobacterium bovis on specimens obtained through a variety of field surveillance methods. Although these blood assays cannot replace mass culling, information on their performance may prove useful as wildlife disease managers develop innovative methods of detecting infected animals where mass culling is publicly unacceptable and cannot be used as a control strategy.

Evaluation of the results of Mycobacterium tuberculosis direct test (MTD) and Mycobacterial culture in urine samples

Tuberculosis remains a public health problem in Turkey. Rapid detection of Mycobacterium tuberculosis plays a key role in control of infection. In this article, the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (MTD) was evaluated for detection of M. tuberculosis in urine samples. The performance of the MTD was very good and appropriate for routine laboratory diagnosis.

Outcomes of a Standardized Triple‐Drug Regimen for the Treatment of Nontuberculous Mycobacterial Pulmonary Infection

The treatment of fibrocavitatory pulmonary infection due to Mycobacterium avium complex and Mycobacterium malmoense poses a challenge. This study assessed microbial, inflammatory, radiographic, and clinical outcomes for a standardized 24-month triple-drug regime. Following treatment completion, all patients had fewer symptoms, experienced a reduction in systemic inflammation, and had negative sputum mycobacterial culture results.

The Interval Between Initiation of Anti-tuberculosis Treatment in Patients with Culture-positive Pulmonary Tuberculosis and Receipt of Drug-susceptibility Test Results

Although mycobacterial culture and the subsequent drug-susceptibility test (DST) for anti-tuberculosis (TB) drugs take several months to complete using solid media, there are no reports on the turnaround times of these tests under clinical conditions. The aim of this study was to determine the interval between initiation of anti-TB treatment and receipt of DST requested at an outpatient clinic. We prospectively enrolled patients with culture-positive pulmonary TB at Seoul National University Hospital from September 2002 to December 2004. Patients were followed up monthly. Mycobacterial cultures were done using Ogawa media at Seoul National University Hospital. DST were performed at the Korean Institute of Tuberculosis. Of the 104 patients enrolled, 54 were male. The median age was 41 yr. The median interval from initiation of anti-TB treatment to receipt of mycobacterial culture results by clinicians was 37 days (range, 0-89 days). The median interval from initiation of treatment to confirmation of DST by requesting clinicians was 80.5 days (range, 28-145 days). Clinicians only received the results of DST more than two months after initiation of treatment when they followed up patients monthly and mycobacterial culture was performed using solid media.

Prevalence of and risk factors for paratuberculosis in purebred beef cattle

To estimate the prevalence of paratuberculosis in purebred beef cattle in Texas and identify risk factors for seropositivity. Epidemiologic survey. 4,579 purebred cattle from 115 beef ranches in Texas. Blood was collected, and serum was analyzed for antibodies with a commercial ELISA. Fecal samples were collected and frozen at -80 degrees C until results of the ELISA were obtained, and feces from seropositive cattle were submitted for mycobacterial culture. Herd owners completed a survey form on management factors. Results of the ELISA were positive for 137 of the 4,579 (3.0%) cattle, and 50 of the 115 (43.8%) herds had at least 1 seropositive animal. Results of mycobacterial culture were positive for 10 of the 137 (7.3%) seropositive cattle, and 9 of the 50 (18%) seropositive herds had at least 1 animal for which results of mycobacterial culture were positive. Risk factors for seropositivity included water source, use of dairy-type nurse cows, previous clinical signs of paratuberculosis, species of cattle (Bos taurus vs Bos indicus), and location. Results suggested that seroprevalence of paratuberculosis among purebred beef cattle in Texas may be greater than seroprevalence among beef cattle in the United States as a whole; however, this difference could be attributable to breed or regional differences in infection rates or interference by cross-reacting organisms. Veterinarians should be aware of risk factors for paratuberculosis as well as the possibility that unexpected serologic results may be found in some herds.

Evaluation of enzyme-linked immunosorbent assays performed on milk and serum samples for detection of paratuberculosis in lactating dairy cows

To determine whether results obtained for milk and serum samples with ELISAs intended for diagnosis of paratuberculosis in dairy cows were comparable to results obtained by means of mycobacterial culture of fecal samples. Cross-sectional study. 689 lactating dairy cows in 9 Ontario herds. Milk, serum, and fecal samples were obtained from all cows. Fecal samples were submitted for mycobacterial culture. Serum samples were tested with a commercially available ELISA for antibodies against Mycobacterium paratuberculosis, and preserved milk samples were tested with an indirect ELISA for antibodies against M paratuberculosis. Results were positive for 130 of the 689 (18.9%) serum samples, 77 of the 689 (11.1%) milk samples, and 72 of the 689 (10.4%) fecal samples. The level of agreement between results for milk and serum samples was only moderate. Proportions of positive results for serum and fecal samples were significantly different, but proportions of positive results for milk and fecal samples were not significantly different. In addition, results for milk samples had a higher level of agreement with results of mycobacterial culture than did results for serum samples. Results suggest that the indirect ELISA used on milk samples may be a convenient method of detecting paratuberculosis in dairy herds.