Gunnar Bjune

Persistence of DNA from Mycobacterium tuberculosis in superficially normal lung tissue during latent infection

BACKGROUND A third of the worlds population has latent infection with Mycobacterium tuberculosis, and in areas of low endemicity, most cases of active tuberculosis arise as a result of reactivation of latent bacilli. We sought to establish the cellular location of these latent organisms to facilitate their elimination. METHODS We applied in-situ PCR to sections of macroscopically normal lung tissue from 13 individuals from Ethiopia and 34 from Mexico who had died from causes other than tuberculosis. Sections of lung tissue from six Norwegian individuals (ie, individuals from a non-endemic population) acted as negative controls, and six Ethiopian tuberculosis cases acted as positive controls. FINDINGS Control necropsy samples from the Norwegian individuals were all negative by in-situ PCR and conventional PCR, whereas all samples from known Ethiopian tuberculosis cases were positive by both methods. However, in macroscopically normal lung tissue from Ethiopian and Mexican individuals without tuberculous lesions, the in-situ PCR revealed five of 13 and ten of 34 positive individuals, respectively. These results were confirmed by conventional PCR with extracted DNA. Positive cells included alveolar and interstitial macrophages, type II pneumocytes, endothelial cells, and fibroblasts. INTERPRETATION M. tuberculosis can persist intracellularly in lung tissue without histological evidence of tuberculous lesions. M. tuberculosis DNA is situated not only in macrophages but also in other non-professional phagocytic cells. These findings contradict the dominant view that latent organisms exist in old classic tuberculous lesions, and have important implications for strategies aimed at the elimination of latent and persistent bacilli.

Spread of Drug-Resistant Mycobacterium tuberculosis Strains of the Beijing Genotype in the Archangel Oblast, Russia

ABSTRACT A collection of 119 strains of Mycobacterium tuberculosis isolated from patients with pulmonary tuberculosis in the Archangel Oblast, Russia, in 1998 and 1999 were studied by using restriction fragment length polymorphism (RFLP) analysis with the IS6110 probe and spoligotyping. Resistance of the strains to antituberculosis drugs was analyzed by the BACTEC method, and mutations associated with rifampin resistance were detected by using the Inno-LiPA Rif. TB test. RFLP analysis and spoligotyping demonstrated that 53 (44.5%) of the strains belonged to the Beijing genotype. These strains showed a significantly higher rate of resistance than M. tuberculosis strains of other genotypes circulating in the region. In particular, 43.4% of the strains of the Beijing genotype were multidrug resistant; in contrast, only 10.6% of the other strains were. Of the strains of the Beijing genotype, 92.5% were part of a cluster, while only 33.3% of the remaining strains were clustered. Analysis of the medical records of the patients demonstrated that individuals infected with a strain of the Beijing genotype were significantly more likely to be alcohol abusers and to have chronic obstructive pulmonary disease prior to the tuberculosis diagnosis. Multivariate analysis showed that both variables were independently associated with infection by strains belonging to the Beijing genotype. Our study demonstrated that strains of the Beijing genotype are an important cause of tuberculosis in the Archangel Oblast and that dissemination of these strains is associated with the high incidence of drug resistance.

The protective role of antibody responses during Mycobacterium tuberculosis infection

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is one of the most important infectious diseases globally. Immune effector mechanisms that lead to protection or development of clinical disease are not fully known. It is generally accepted that cell‐mediated immunity (CMI) plays a pivotal role in controlling Mtb infection, whereas antibody responses are believed to have no protective role. This generalization is based mainly on early classical experiments that lacked standard protocols, and the T helper type 1 (Th1)/Th2 paradigm. According to the Th1/Th2 paradigm Th1 cells protect the host from intracellular pathogens, whereas Th2 cells protect form extracellular pathogens. During the last two decades, the Th1/Th2 paradigm has dominated not only our understanding of immunity to infectious pathogens but also our approach to vaccine design. However, the last few years have seen major discrepancies in this model. Convincing evidence for the protective role of antibodies against several intracellular pathogens has been established. Studies of B cell‐deficient mice, severe combined immunodeficiency (SCID) mice, passive immunization using monoclonal (mAb) and polyclonal antibodies and immune responses against specific mycobacterial antigens in experimental animals reveal that, in addition to a significant immunomodulatory effect on CMI, antibodies play an essential protective role against mycobacterial infections. In this review, our current understanding of the essential role of antibodies during Mtb infections, limitations of the Th1/Th2 model and the unfolding interdependence and mutual regulatory relationships between the humoral and CMI will be presented and discussed.

Risk factors for incomplete vaccination and missed opportunity for immunization in rural Mozambique

BackgroundInadequate levels of immunization against childhood diseases remain a significant public health problem in resource-poor areas of the globe. Nonetheless, the reasons for incomplete vaccination and non-uptake of immunization services are poorly understood. This study aimed at finding out the reasons for non-vaccination and the magnitude of missed opportunities for vaccination in children less than two years of age in a rural area in southern Mozambique.MethodsMothers of children under two years of age (N = 668) were interviewed in a cross-sectional study. The Road-to-Health card was utilized to check for completeness and correctness of vaccination schedule as well as for identifying the appropriate use of all available opportunities for vaccination. The chi-square test and the logistic regression were used for statistical analysis.ResultsWe found that 28.2% of the children had not completed the vaccination program by two years of age, 25.7% had experienced a missed opportunity for vaccination and 14.9% were incorrectly vaccinated. Reasons for incomplete vaccination were associated with accessibility to the vaccination sites, no schooling of mothers and children born at home or outside Mozambique.ConclusionEfforts to increase vaccination coverage should take into account factors that contribute to the incomplete vaccination status of children. Missed opportunities for vaccination and incorrect vaccination need to be avoided in order to increase the vaccine coverage for those clients that reach the health facility, specially in those countries where health services do not have 100% of coverage.

Patient and health care system delays in the start of tuberculosis treatment in Norway

BackgroundDelay in start of tuberculosis (TB) treatment has an impact at both the individual level, by increasing the risk of morbidity and mortality, and at the community level, by increasing the risk of transmission. The aims of this study were to assess the delays in the start of treatment for TB patients in Oslo/Akershus region, Norway and to analyze risk factors for the delays.MethodsThis study was based on information from the National TB Registry, clinical case notes from hospitals and referral case notes from primary health care providers. Delays were divided into patient, health care system and total delays. The association with sex, birthplace, site of the disease and age group was analyzed by multiple linear regression.ResultsAmong the 83 TB patients included in this study, 71 (86%) were born abroad. The median patient, health care system and total delays were 28, 33 and 63 days respectively, with a range of 1–434 days. In unadjusted analysis, patient delay and health care system delay did not vary significantly between men and women, according to birthplace or age group. Patients with extra-pulmonary TB had a significantly longer patient, health care system and total delay compared to patients with pulmonary TB. Median total delay was 81 and 56 days in the two groups of TB patients respectively. The health care system delay exceeded the patient delay for those born in Norway. The age group 60+ years had significantly shorter patient delay than the reference group aged 15–29 years when adjusted for multiple covariates. Also, in the multivariate analysis patients born in Norway had significantly longer health care system delay than patients born abroad.ConclusionA high proportion of patients had total delays in start of TB treatment exceeding two months. This study emphasizes the need of awareness of TB in the general population and among health personnel. Extra-pulmonary TB should be considered as a differential diagnosis in unresolved cases, especially for immigrants from high TB prevalence countries.

Molecular Epidemiology and Drug Resistance of Mycobacterium tuberculosis Isolates in the Archangel Prison in Russia: Predominance of the W-Beijing Clone Family

Prisons play a significant role in the epidemiology of drug-resistant tuberculosis. A total of 114 Mycobacterium tuberculosis isolates recovered from patients in the Archangel prison (Archangel, Russia) in 2001 were studied using restriction fragment-length polymorphism analysis and spoligotyping. Drug susceptibility was analyzed by the radiometric broth method (BACTEC; Becton Dickinson Diagnostic Systems). According to genotyping studies, 87 (76.3%) of the isolates belonged to the W-Beijing family. Nearly all (96.6%) W-Beijing isolates were part of a cluster, whereas only 25.9% of the other isolates were clustered (P<.001). The largest cluster comprised 43 patients. Multidrug resistance was high among new (34.0%) and previously treated (55.0%) cases. Resistance to ethambutol (OR, 3.4; 95% CI, 1.0-12.7; P=.03) and streptomycin (OR, 4.2; 95% CI, 1.5-11.6; P=.001) was significantly associated with infection with W-Beijing isolates. Tuberculosis due to drug-resistant W-Beijing isolates is a major problem in the Archangel prison.

The emergence of Beijing family genotypes of Mycobacterium tuberculosis and low‐level protection by bacille Calmette–Guérin (BCG) vaccines: is there a link?

The world is confronted with major tuberculosis (TB) outbreaks at a time when the protection of bacillus Calmette–Guérin (BCG) vaccine has become inconsistent and controversial. Major TB outbreaks are caused by a group of genetically similar strains of Mycobacterium tuberculosis (Mtb) strains, including the Beijing family genotypes. The Beijing family genotypes exhibit important pathogenic features such high virulence, multi‐drug resistance and exogenous reinfection. These family strains have developed mechanisms that modulate/suppress immune responses by the host, such as inhibition of apoptosis of infected macrophages, diminished production of interleukin (IL)‐2, interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α and elevated levels of IL‐10 and IL‐18. They demonstrate distinct expression of proteins, such as several species of α‐crystallin (a known Mtb virulence factor), but decreased expression of some antigens such as heat shock protein of 65 kDa, phosphate transport subunit S and a 47‐kDa protein. In addition, the Beijing family strains specifically produce a highly bioactive lipid (a polyketide synthase)‐derived phenolic glycolipid. This altered expression of proteins/glycolipids may be important factors underlying the success of the Beijing family strains. The Beijing family strains are speculated to have originated from South‐east Asia, where BCG vaccination has been used for more than 60 years. The hypothesis that mass BCG vaccination may have been a selective factor that favoured genotypic and phenotypic characteristic acquired by the Beijing family strains is discussed.

Assessing immunization data quality from routine reports in Mozambique

BackgroundWorldwide immunization coverage shows an increase in the past years but the validity of the official reports for measuring change over time has been questioned. Facing this problem, donor supported initiatives like the Global Alliance for Vaccine and Immunizations, have been putting a lot of effort into assessing the quality of data used, since accurate immunization information is essential for the Expanded Program on Immunization managers to track and improve program performance. The present article, discusses the practices on record keeping, reporting and the support mechanism to ensure data quality in Mozambique.MethodsA process evaluation study was carried out in Mozambique in one district (Cuamba) in Niassa Province, between January and March 2003. The study was based on semi-structured interviews, participant observation and review of the data collection materials.ResultsDifferences were found for all vaccine types when comparing facility reports with the tally sheets. The same applies when comparing facility reports with district reports. The study also showed that a routine practice during supervision visits was data quality assessment for the outpatient services but none related to data consistency between the tally sheets and the facility report. For the Expanded Program on Immunization, supervisors concentrated more on the consistency checks between data in the facility reports and the number of vaccines received during the same period. Meetings were based on criticism, for example, why health workers did not reach the target. Nothing in terms of data quality was addressed nor validation rules.ConclusionIn this paper we have argued that the quality of data, and consequently of the information system, must be seen in a broader perspective not focusing only on technicalities (data collection tools and the reporting system) but also on support mechanisms. Implications of a poor data quality system will be reflected in the efficiency of health services facing increased demands, with stagnant or decreasing resources.

Diagnostic evaluation of urinary lipoarabinomannan at an Ethiopian tuberculosis centre.

Direct capture enzyme-linked immunosorbent assay (ELISA) for lipoarabinomannan (LAM) was performed on urine samples from 200 tuberculosis (TB) patients and 800 non-TB patients routinely diagnosed among consecutive suspects in an Ethiopian TB centre. 50 healthy Ethiopians, 50 healthy individuals and 100 non-TB patients from Norway served as controls. Of the TB patients, 139 (69.5%) were positive for acid-fast bacilli (AFB). In the remaining cases the diagnosis was based on suggestive clinical findings. All Ethiopian non-TB patients were AFB negative and showed no clinical evidence of TB. In the Ethiopian groups, 148 (74%) of the TB patients, 105 (13.1%) of the non-TB patients and 5 (10%) of the healthy controls were positive by the LAM-ELISA. 113 (81.3%) of AFB positives and 35 (57.4%) of AFB-negative TB patients had positive LAM-ELISA. In the Norwegian groups all were LAM negative. The sensitivity and specificity of the LAM-ELISA for TB patients versus Ethiopian non-TB patients were 74% and 86.9%, respectively; the positive and negative predictive values were 58.5% and 93.0%. This study suggests that detection of LAM in the urine of TB patients may improve case finding and that diagnostic tests based on this principle may serve as valuable supplemental tools in TB control.Direct capture enzyme-linked immunosorbent assay (ELISA) for lipoarabinomannan (LAM) was performed on urine samples from 200 tuberculosis (TB) patients and 800 non-TB patients routinely diagnosed among consecutive suspects in an Ethiopian TB centre. 50 healthy Ethiopians, 50 healthy individuals and 100 non-TB patients from Norway served as controls. Of the TB patients, 139 (69.5%) were positive for acid-fast bacilli (AFB). In the remaining cases the diagnosis was based on suggestive clinical findings. All Ethiopian non-TB patients were AFB negative and showed no clinical evidence of TB. In the Ethiopian groups, 148 (74%) of the TB patients, 105 (13.1%) of the non-TB patients and 5 (10%) of the healthy controls were positive by the LAM-ELISA. 113 (81.3%) of AFB positives and 35 (57.4%) of AFB-negative TB patients had positive LAM-ELISA. In the Norwegian groups all were LAM negative. The sensitivity and specificity of the LAM-ELISA for TB patients versus Ethiopian non-TB patients were 74% and 86.9%, respectively; the positive and negative predictive values were 58.5% and 93.0%. This study suggests that detection of LAM in the urine of TB patients may improve case finding and that diagnostic tests based on this principle may serve as valuable supplemental tools in TB control.

Psychosocial determinants of sexual activity and condom use intention among youth in Addis Ababa, Ethiopia.

Determinants of sexual activity and intentions for condom use were examined guided by the Attitude, Social influences, and Self-efficacy (ASE) model as a theoretical framework. A total of 561 in and out-of-school youth (15–24 years) in Addis Ababa completed a self-administered questionnaire. A third of them reported sexual intercourse in the past and half of the sexually active used condoms during recent intercourse. Being out-of-school, male, aged 20–24 years, alcohol use and khat (amphetamine-like substance) consumption predicted the likelihood of engagement in sexual activity. Of these variables, however, male sex was more associated with reported condom use during recent sexual intercourse. Self-efficacy, skills, and barriers predicted 23% of the variance in intentions to use condoms. Self-efficacy was also associated with past condom use. Psychosocial constructs predicted more variations in condom use intention for males than for females. In general, self-efficacy was found to be the strongest predictor of the constructs, whereas attitude and social influences were the weakest. The study implies that HIV/AIDS prevention programmes for young people in Ethiopia need to emphasize building assertive communication skills in sexual negotiations and condom use. Minimizing the gender gap in sexual relationships forms the cornerstone for such educational strategies.