Increased production of IL-4 and IL-12p40 from bronchoalveolar lavage cells are biomarkers of Mycobacterium tuberculosis in the sputum

BACKGROUND

Tuberculosis (TB) causes 1.45 million deaths annually world wide, the majority of which occur in the developing world. Active TB disease represents immune failure to control latent infection from airborne spread. Acid-fast bacillus (AFB) seen on sputum smear is a biomarker for contagiousness.

METHODS

We enrolled 73 tuberculosis patients with extensive infiltrates into a research study using bronchoalveolar lavage (BAL) to sample lung immune cells and assay BAL cell cytokine production. All patients had sputum culture demonstrating Mycobacterium tuberculosis and 59/73 (81%) had AFB identified by microscopy of the sputum. Compared with smear negative patients, smear positive patients at presentation had a higher proportion with smoking history, a higher proportion with temperature >38.5(0) C, higher BAL cells/ml, lower percent lymphocytes in BAL, higher IL-4 and IL-12p40 in BAL cell supernatants. There was no correlation between AFB smear and other BAL or serum cytokines. Increasing IL-4 was associated with BAL PMN and negatively associated with BAL lymphocytes. Each 10-fold increase in BAL IL-4 and IL-12p40 increased the odds of AFB smear positivity by 7.4 and 2.2-fold, respectively, in a multi-variable logistic model.

CONCLUSION

Increasing IL-4 and IL-12p40 production by BAL cells are biomarkers for AFB in sputum of patients who present with radiographically advanced TB. They likely reflect less effective immune control of pathways for controlling TB, leading to patients with increased infectiousness.

Evidence-based consensus on the insertion of central venous access devices: definition of minimal requirements for training

There is a lack of standard minimal requirements for the training of insertion techniques and maintenance of central venous access devices (CVADs). An international evidence-based consensus task force was established through the World Congress of Vascular Access (WoCoVA) to provide definitions and recommendations for training and insertion of CVADs. Medical literature published from February 1971 to April 2012 regarding 'central vascular access', 'training', 'competency', 'simulation', and 'ultrasound' was reviewed on Pubmed, BioMed Central, ScienceDirect, and Scopus databases. The GRADE and the GRADE-RAND methods were utilized to develop recommendations. Out of 156 papers initially identified, 83 papers described training for central vascular access placement. Sixteen recommendations are proposed by this task force, each with an evidence level, degree of consensus, and recommendation grade. These recommendations suggest central venous access education include didactic or web-based teaching with insertion procedure, infection prevention, complications, care, and maintenance of devices, along with laboratory models and tools for simulation practice incorporating ultrasound. Clinical competence should be determined by observation during clinical practice using a global rating scale rather than by the number of procedures performed. Ensuring safe insertion and management of central venous devices requires standardized education, simulation practice, and supervised insertions.

Development of a simple reliable radiographic scoring system to aid the diagnosis of pulmonary tuberculosis

Rationale

Chest radiography is sometimes the only method available for investigating patients with possible pulmonary tuberculosis (PTB) with negative sputum smears. However, interpretation of chest radiographs in this context lacks specificity for PTB, is subjective and is neither standardized nor reproducible. Efforts to improve the interpretation of chest radiography are warranted.

Objectives

To develop a scoring system to aid the diagnosis of PTB, using features recorded with the Chest Radiograph Reading and Recording System (CRRS).

Methods

Chest radiographs of outpatients with possible PTB, recruited over 3 years at clinics in South Africa were read by two independent readers using the CRRS method. Multivariate analysis was used to identify features significantly associated with culture-positive PTB. These were weighted and used to generate a score.

Results

473 patients were included in the analysis. Large upper lobe opacities, cavities, unilateral pleural effusion and adenopathy were significantly associated with PTB, had high inter-reader reliability, and received 2, 2, 1 and 2 points, respectively in the final score. Using a cut-off of 2, scores below this threshold had a high negative predictive value (91.5%, 95%CI 87.1,94.7), but low positive predictive value (49.4%, 95%CI 42.9,55.9). Among the 382 TB suspects with negative sputum smears, 229 patients had scores <2; the score correctly ruled out active PTB in 214 of these patients (NPV 93.4%; 95%CI 89.4,96.3). The score had a suboptimal negative predictive value in HIV-infected patients (NPV 86.4, 95% CI 75,94).

Conclusions

The proposed scoring system is simple, and reliably ruled out active PTB in smear-negative HIV-uninfected patients, thus potentially reducing the need for further tests in high burden settings. Validation studies are now required.

14-day bactericidal activity of PA-824, bedaquiline, pyrazinamide, and moxifloxacin combinations: a randomised trial

BACKGROUND

New drugs, but also shorter, better-tolerated regimens are needed to tackle the high global burden of tuberculosis complicated by drug resistance and retroviral disease. We investigated new multiple-agent combinations over the first 14 days of treatment to assess their suitability for future development.

METHODS

In this prospective, randomised, early bactericidal activity (EBA) study, treatment-naive, drug-susceptible patients with uncomplicated pulmonary tuberculosis were admitted to hospitals in Cape Town, South Africa, between Oct 7, 2010, and Aug 19, 2011. Patients were randomised centrally by computer-generated randomisation sequence to receive bedaquiline, bedaquiline-pyrazinamide, PA-824-pyrazinamide, bedaquiline-PA-824, PA-824-moxifloxacin-pyrazinamide, or unmasked standard antituberculosis treatment as positive control. The primary outcome was the 14-day EBA assessed in a central laboratory from the daily fall in colony forming units (CFU) of M tuberculosis per mL of sputum in daily overnight sputum collections. Bilinear regression curves were fitted for each group separately and groups compared with ANOVA for ranks, followed by pair-wise comparisons adjusted for multiplicity. Clinical staff were partially masked but laboratory personnel were fully masked. This study is registered, NCT01215851.

FINDINGS

The mean 14-day EBA of PA-824-moxifloxacin-pyrazinamide (n=13; 0·233 [SD 0·128]) was significantly higher than that of bedaquiline (14; 0·061 [0·068]), bedaquiline-pyrazinamide (15; 0·131 [0·102]), bedaquiline-PA-824 (14; 0·114 [0·050]), but not PA-824-pyrazinamide (14; 0·154 [0·040]), and comparable with that of standard treatment (ten; 0·140 [0·094]). Treatments were well tolerated and appeared safe. One patient on PA-824-moxifloxacin-pyrazinamide was withdrawn because of corrected QT interval changes exceeding criteria prespecified in the protocol.

INTERPRETATION

PA-824-moxifloxacin-pyrazinamide is potentially suitable for treating drug-sensitive and multidrug-resistant tuberculosis. Multiagent EBA studies can contribute to reducing the time needed to develop new antituberculosis regimens.

FUNDING

The Global Alliance for TB Drug Development (TB Alliance).

A systematic review on the use of prophylactic mesh during primary stoma formation to prevent parastomal hernia formation

AIM

Despite advances in surgical technique, parastomal herniation is common. This systematic review aims to assess the efficacy of prophylactic mesh at primary operation in reducing the incidence of parastomal hernia.

METHOD

Medline, EMBASE and CENTRAL were searched for relevant publications between January 1980 and January 2010. The search strategy included text terms and MESH headings for parastomal hernia, mesh and prevention and/or prophylaxis of hernia. No language restrictions were applied. Bibliographies from the papers requested in full were manually checked. All randomized controlled trials were included regardless of the language of publication. Results were extracted from the papers by two observers independently on a predefined data sheet. Disagreements were resolved by discussion. REVMAN 5 was used for statistical analysis.

RESULTS

Of 27 possible studies three randomized controlled trials fulfilled the criteria for systematic review, with a total of 128 patients (mesh 64, no mesh 64). The two study groups were well matched demographically. The incidence of parastomal hernia in the mesh group was 12.5% (8/64) compared with 53% (34/64) in the control group (P < 0.0001). There was no difference in mesh related morbidity in the two groups.

CONCLUSION

Although only three trials with 128 patients fulfilled the criteria for this systematic review, the data suggest that the use of prophylactic prosthetic mesh at the time of primary stoma formation reduces the incidence of parastomal hernia.

Laparoscopic fellowship training can deliver a competent laparoscopic surgeon and trainer

AIM

The study investigated whether experience gained during a UK laparoscopic colorectal fellowship enabled the fellow subsequently to train consultant colleagues in laparoscopic surgery.

METHOD

In one unit a newly appointed post-laparoscopic fellowship consultant (PFC) mentored his other two colleagues. Prospectively collected data regarding surgical outcome were compared with those of the year preceding the PFC appointment.

RESULTS

In the preceding year 18.5% of 260 resections were attempted laparoscopically. This increased to 92.6% (of 270) in the year after (P < 0.0001). Respective conversion rates were 4.2% and 8.4% (P = 0.5524). In the first 6 months after PFC appointment, mentored consultants performed 23 supervised cases. In the second 6 months they carried out 58 procedures independently and trainees performed 38 supervised cases. There was no significant difference in anastomotic leakage and readmission and 30-day mortality rates between the pre- and post-PFC periods.

CONCLUSION

A laparoscopic fellowship enables the PFC to mentor consultant colleagues safely and effectively.

Early bactericidal activity of delamanid (OPC-67683) in smear-positive pulmonary tuberculosis patients

BACKGROUND

Delamanid (OPC-67683) is a novel mycolic acid biosynthesis inhibitor active against Mycobacterium tuberculosis at a low minimum inhibitory concentration.

METHODS

Forty-eight patients with smear-positive tuberculosis (63% male; 54.7 ± 9.9 kg; 30.7 ± 10.8 years) were randomly assigned to receive delamanid 100, 200, 300 or 400 mg daily for 14 days. Colony forming units (cfu) of M. tuberculosis were counted on agar plates from overnight sputum collections to calculate early bactericidal activity (EBA), defined as fall in log(10) cfu/ml sputum/day.

RESULTS

The EBA of delamanid was monophasic and not significantly different between dosages; however, more patients receiving 200 mg (70%) and 300 mg (80%) experienced a response of ≥0.9 log(10) cfu/ml sputum decline over 14 days than those receiving 100 mg (45%) and 400 mg (27%). The average EBA of all dosages combined (0.040 ± 0.056 log(10) cfu/ml sputum/day) was significant from day 2 onward. Delamanid exposure was less than dosage-proportional, reaching a plateau at 300 mg, likely due to dose-limited absorption. Moderate but significant correlation was found between C(max) and EBA, indicating exposure dependence. Delamanid was well tolerated without significant toxicity.

CONCLUSIONS

Delamanid at all dosages was safe, well tolerated and demonstrated significant exposure-dependent EBA over 14 days, supporting further investigation of its pharmacokinetics and anti-tuberculosis activity.

Predominance of interleukin-22 over interleukin-17 at the site of disease in human tuberculosis

The inflammatory response to Mycobacterium tuberculosis (M.tb) at the site of disease is Th1 driven. Whether the Th17 cytokines, IL-17 and IL-22, contribute to this response in humans is unknown. We hypothesized that IL-17 and IL-22 contribute to the inflammatory response in pleural and pericardial disease sites of human tuberculosis (TB). We studied pleural and pericardial effusions, established TB disease sites, from HIV-uninfected TB patients. Levels of soluble cytokines were measured by ELISA and MMP-9 by luminex. Bronchoalveolar lavage or pericardial mycobacteria-specific T cell cytokine expression was analyzed by intracellular cytokine staining. IL-17 was not abundant in pleural or pericardial fluid. IL-17 expression by mycobacteria-specific disease site T cells was not detected in healthy, M.tb-infected persons, or patients with TB pericarditis. These data do not support a major role for IL-17 at established TB disease sites in humans. IL-22 was readily detected in fluid from both disease sites. These IL-22 levels exceeded matching peripheral blood levels. Further, IL-22 levels in pericardial fluid correlated positively with MMP-9, an enzyme known to degrade the pulmonary extracellular matrix. We propose that our findings support a role for IL-22 in TB-induced pathology or the resulting repair process.

Are interferon-γ release assays useful for diagnosing active tuberculosis in a high-burden setting?

Although interferon-γ release assays (IGRAs) are intended for diagnosing latent tuberculosis (TB), we hypothesised that in a high-burden setting: 1) the magnitude of the response when using IGRAs can distinguish active TB from other diagnoses; 2) IGRAs may aid in the diagnosis of smear-negative TB; and 3) IGRAs could be useful as rule-out tests for active TB. We evaluated the accuracy of two IGRAs (QuantiFERON®-TB Gold In-tube (QFT-GIT) and T-SPOT®.TB) in 395 patients (27% HIV-infected) with suspected TB in Cape Town, South Africa. IGRA sensitivity and specificity (95% CI) were 76% (68-83%) and 42% (36-49%) for QFT-GIT and 84% (77-90%) and 47% (40-53%) for T-SPOT®.TB, respectively. Although interferon-γ responses were significantly higher in the TB versus non-TB groups (p<0.0001), varying the cut-offs did not improve discriminatory ability. In culture-negative patients, depending on whether those with clinically diagnosed TB were included or excluded from the analysis, the negative predictive value (NPV) of QFT-GIT, T-SPOT®.TB and chest radiograph in smear-negative patients varied between 85 and 89, 87 and 92, and 98% (for chest radiograph), respectively. Overall accuracy was independent of HIV status and CD4 count. In a high-burden setting, IGRAs alone do not have value as rule-in or -out tests for active TB. In smear-negative patients, chest radiography had better NPV even in HIV-infected patients.

High prevalence of smoking among patients with suspected tuberculosis in South Africa

There is growing evidence that tobacco smoking is an important risk factor for tuberculosis (TB). There are no data validating the accuracy of self-reported smoking in TB patients and limited data about the prevalence of smoking in TB patients from high-burden settings. We performed a cross-sectional analysis of 500 patients with suspected TB in Cape Town, South Africa. All underwent comprehensive diagnostic testing. The accuracy of their self-reported smoking status was determined against serum cotinine levels. Of the 424 patients included in the study, 56 and 60% of those with active and latent TB infection (LTBI), respectively, were current smokers. Using plasma cotinine as a reference standard, the sensitivity of self-reported smoking was 89%. No statistically significant association could be found between smoking and active TB or LTBI. In Cape Town, the prevalence of smoking among patients with suspected and confirmed TB was much higher than in the general South African population. Self-reporting is an accurate measure of smoking status. These results suggest the need to actively incorporate tobacco cessation programmes into TB services in South Africa.

Fusion of local and global detection systems to detect tuberculosis in chest radiographs

Automatic detection of tuberculosis (TB) on chest radiographs is a difficult problem because of the diverse presentation of the disease. A combination of detection systems for abnormalities and normal anatomy is used to improve detection performance. A textural abnormality detection system operating at the pixel level is combined with a clavicle detection system to suppress false positive responses. The output of a shape abnormality detection system operating at the image level is combined in a next step to further improve performance by reducing false negatives. Strategies for combining systems based on serial and parallel configurations were evaluated using the minimum, maximum, product, and mean probability combination rules. The performance of TB detection increased, as measured using the area under the ROC curve, from 0.67 for the textural abnormality detection system alone to 0.86 when the three systems were combined. The best result was achieved using the sum and product rule in a parallel combination of outputs.

Inflammatory bowel disease in young people: the case for transitional clinics

BACKGROUND

The incidence of inflammatory bowel disease (IBD) is increasing among adolescents. In all, 25% of patients are diagnosed before the age of 16, when they are traditionally transferred from the pediatric to the adult service.

METHODS

We conducted a retrospective case-controlled study to characterize patients treated in a novel transitional adolescent-young adult IBD clinic. This compared disease extent, radiation exposure, therapeutic strategy, and requirement for surgery in 100 adolescents with controls from our adult IBD clinic matched for disease duration.

RESULTS

The median (range) ages for the adolescent and adult population was 19 (16-28) and 43 (24-84), with a median age at diagnosis of 15 (3-26) and 39 (13-82) respectively (P < 0.001). Crohn's disease was significantly more common in the adolescents. Disease distribution was ileocolonic in 69% of adolescents and 28% of adults, restricted to the ileum in 20% of adolescents and 47% of adults, and colonic only in 11% and 22%, respectively. Upper gastrointestinal involvement occurred in 23% of adolescents, but was not seen in adults (P < 0.01). Total ulcerative colitis was seen in 67% of adolescents and 44% of adults (P < 0.01). Contrary to previous data adolescents did not receive more ionizing radiation than adults. Requirement for immunosuppressive therapy was higher in the adolescent group (53% versus 31%, respectively, P < 0.01). Likewise, 20% of adolescents had required biological therapy compared to only 8% in the adult cohort (P < 0.05).

CONCLUSIONS

Gastroenterologists should recognize that IBD is more complex when presenting in adolescence and our data support the creation of specific adolescent transitional clinics.

Clinical utility of a commercial LAM-ELISA assay for TB diagnosis in HIV-infected patients using urine and sputum samples

BACKGROUND

The accurate diagnosis of TB in HIV-infected patients, particularly with advanced immunosuppression, is difficult. Recent studies indicate that a lipoarabinomannan (LAM) assay (Clearview-TB(R)-ELISA) may have some utility for the diagnosis of TB in HIV-infected patients; however, the precise subgroup that may benefit from this technology requires clarification. The utility of LAM in sputum samples has, hitherto, not been evaluated.

METHODS

LAM was measured in sputum and urine samples obtained from 500 consecutively recruited ambulant patients, with suspected TB, from 2 primary care clinics in South Africa. Culture positivity for M. tuberculosis was used as the reference standard for TB diagnosis.

RESULTS

Of 440 evaluable patients 120/387 (31%) were HIV-infected. Urine-LAM positivity was associated with HIV positivity (p = 0.007) and test sensitivity, although low, was significantly higher in HIV-infected compared to uninfected patients (21% versus 6%; p<0.001), and also in HIV-infected participants with a CD4 <200 versus >200 cells/mm(3) (37% versus 0%; p = 0.003). Urine-LAM remained highly specific in all 3 subgroups (95%-100%). 25% of smear-negative but culture-positive HIV-infected patients with a CD4 <200 cells/mm(3) were positive for urine-LAM. Sputum-LAM had good sensitivity (86%) but poor specificity (15%) likely due to test cross-reactivity with several mouth-residing organisms including actinomycetes and nocardia species.

CONCLUSIONS

These preliminary data indicate that in a high burden primary care setting the diagnostic usefulness of urine-LAM is limited, as a rule-in test, to a specific patient subgroup i.e. smear-negative HIV-infected TB patients with a CD4 count <200 cells/mm(3), who would otherwise have required further investigation. However, even in this group sensitivity was modest. Future and adequately powered studies in a primary care setting should now specifically target patients with suspected TB who have advanced HIV infection.

Chest radiograph reading and recording system: evaluation for tuberculosis screening in patients with advanced HIV

SETTING

An antiretroviral treatment (ART) service in Gugulethu township, Cape Town, South Africa.

OBJECTIVE

To assess the inter-observer agreement when using the chest radiographic reading and reporting system (CRRS) to detect radiographic abnormalities in patients with advanced human immunodeficiency virus (HIV) associated immunodeficiency being actively screened for tuberculosis (TB). Second, to assess the associated performance characteristics of radiology as a routine screening test for detection of culture-confirmed pulmonary TB.

DESIGN

Radiographs from a study in which patients were actively screened for TB just before starting ART were independently reported by two CRRS-certified readers blinded to clinical status.

RESULTS

Good kappa statistic agreements between observers were found when reporting any radiological abnormality consistent with TB among all patients (n = 203, kappa = 0.63, 95%CI 0.52-0.73) and among those with culture-confirmed TB (n = 53, kappa = 0.61, 95%CI 0.40-0.83). However, in comparison with sputum culture, the sensitivity (0.68, 95%CI 0.54-0.79) and specificity (0.53, 95%CI 0.45-0.61) of radiology in this patient group were low.

CONCLUSION

This study provides evidence of the good inter-observer agreement using the CRRS standardised reporting methodology when used among patients with advanced HIV-associated immunodeficiency and a high prevalence of culture-proven pulmonary TB. The utility of radiology as a screening test for TB in this patient group, however, remains limited.

HIV-1 infection impairs the bronchoalveolar T-cell response to mycobacteria

RATIONALE

The risk of developing active tuberculosis in persons with latent Mycobacterium tuberculosis infection is substantially increased shortly after HIV-1 seroconversion. Immune responses in the lung are important to restrict the growth of M. tuberculosis to prevent the development of disease.

OBJECTIVES

To investigate innate and adaptive immune responses to M. tuberculosis in bronchoalveolar lavage from HIV-1-infected persons without active tuberculosis.

METHODS

Peripheral blood was drawn and bronchoalveolar lavage (BAL) performed on healthy, HIV-1-uninfected (n = 21) and HIV-1-infected (n = 15) adults. Growth of M. tuberculosis was assessed in monocytes and alveolar macrophages. Cytokine expression by mycobacteria-specific CD4 and CD8 T cells was measured by intracellular cytokine staining or IFN-gamma ELISpot.

MEASUREMENTS AND MAIN RESULTS

Mycobacterial growth in monocytes or alveolar macrophages from HIV-1-infected and -uninfected persons did not differ. Total CD4 T-cell frequencies in BAL were lower in HIV-1-infected than in HIV-1-uninfected persons (P < 0.001). Mycobacteria (bacillus Calmette-Guérin)-specific CD4 T-cell responses in BAL were severely impaired: Frequencies of cells expressing IFN-gamma or tumor necrosis factor (TNF)-alpha, as well as polyfunctional cells, expressing IFN-gamma, TNF-alpha, and IL-2 together, were lower in HIV-1-infected persons than in uninfected controls (P < 0.01 for all).

CONCLUSIONS

In addition to a total CD4 T-cell deficit, the function of mycobacteria-specific CD4 T cells is significantly impaired in the lung of HIV-1-infected persons, which may account for the HIV-1-associated elevated risk for developing tuberculosis.

Shipboard testing of the efficacy of SeaKleen as a ballast water treatment to eliminate non-indigenous species aboard a working tanker in Pacific waters

Trials were conducted aboard the tanker Seabulk Mariner to test a natural product, SeaKleen, as a biocide controlling non-indigenous populations of plankton and bacteria in ballast water. SeaKleen was dosed into matched ballast tanks at two different concentrations, 0.8 mg L(-1) active ingredient (a.i.) and 1.6 mg L(-1) a.i. during ballasting off the Oregon coast during a three-day passage to Prince William Sound, Alaska. Live organism counts from treated ballast water were compared with those from untreated (control tank) water collected from the same source location. Shipboard chemical analyses were made to verify dose and quantify chemical degradation and residuals following dilution. Results indicated that both SeaKleen doses resulted in complete zooplankton and phytoplankton mortality and that the higher dose (1.6 mg L(-1) a.i.) caused a two-log removal of culturable bacteria over a 92 h grow-out period. Spectrophotometry confirmed initial dosing to within 5% of nominal values. Shipboard bioassays were conducted using larval fish (Cyprinodon variegatus), brine shrimp (Artemia salina) and the bioluminescent dinoflagellate Pyrocystis lunula. Exposure of the test organisms to water drawn from treated ballast tanks 48 h after SeaKleen was added to the tanks resulted in 100% mortalities in Cyprinodon and Pyrocystis at both doses. Corresponding mortalities for Artemia larvae were 100% and 60% for high and low SeaKleen doses, respectively. Toxicity testing of treated water, subjected to varying dilutions, indicated that residual toxicity to even the most sensitive organisms would be eliminated once the discharge had dispersed beyond 100 feet from the vessel.