A novel derivative of the fungal antimicrobial peptide plectasin is active against Mycobacterium tuberculosis.

Tuberculosis has been reaffirmed as the infectious disease causing most deaths in the world. Co-infection with HIV and the increase in multi-drug resistant Mycobacterium tuberculosis strains complicate treatment and increases mortality rates, making the development of new drugs an urgent priority. In this study we have identified a promising candidate by screening antimicrobial peptides for their capacity to inhibit mycobacterial growth. This non-toxic peptide, NZX, is capable of inhibiting both clinical strains of M. tuberculosis and an MDR strain at therapeutic concentrations. The therapeutic potential of NZX is further supported in vivo where NZX significantly lowered the bacterial load with only five days of treatment, comparable to rifampicin treatment over the same period. NZX possesses intracellular inhibitory capacity and co-localizes with intracellular bacteria in infected murine lungs. In conclusion, the data presented strongly supports the therapeutic potential of NZX in future anti-TB treatment.

Performance of QuantiFERON-TB Gold Plus for detection of latent tuberculosis infection in pregnant women living in a tuberculosis- and HIV-endemic setting.

We evaluated the performance of QuantiFERON-TB Gold Plus (QFT-Plus), which includes two Mycobacterium tuberculosis antigen formulations (TB1 and TB2), for detection of latent tuberculosis infection during pregnancy. Eight-hundred-twenty-nine Ethiopian pregnant women (5.9% HIV-positive) were tested with QFT-Plus, with bacteriological sputum analysis performed for women with clinically suspected tuberculosis and HIV-positive women irrespective of clinical presentation. QFT-Plus read-out was categorized according to the conventional cut-off (0.35 IU/ml) for both antigen formulations. In addition, we analysed the distribution of QFT-Plus results within a borderline zone (0.20-0.70 IU/ml), and interferon-γ response in relation to HIV infection and gestational age. Two-hundred-seventy-seven women (33%) were QFT-Plus-positive (HIV-positive 16/49 [33%]; HIV-negative 261/780 [33%]). There was a strong agreement between the two antigen formulations (κ = 0.92), with discordant results in 29 cases (3.5%). Whereas discordant QFT-Plus results were rare in pregnancy, several results with both TB1 and TB2 within the borderline range were observed (11/49 [22%] vs. 43/780 [5.5%] in HIV-positive and HIV-negative women, respectively; p<0.0001). HIV-positive women had lower absolute interferon-γ levels (TB1: 0.47 vs. 2.16 IU/ml; p<0.001, TB2: 0.49 vs. 2.24 IU/ml, p<0.001, considering results ≥0.20 IU/ml) compared to HIV-negative women. QFT-Plus-positive women who submitted samples at later stages of pregnancy had lower mitogen- (p<0.001) but higher TB-antigen-specific (p = 0.031 for TB1, p = 0.061 for TB2) interferon-γ response. Considering their lower capacity to produce TB-specific interferon-γ, a lower cut-off level for defining QFT-Plus-positivity may be considered in HIV-positive pregnant women.

ESX-1 exploits type I IFN-signalling to promote a regulatory macrophage phenotype refractory to IFNγ-mediated autophagy and growth restriction of intracellular mycobacteria.

The ability of macrophages to eradicate intracellular pathogens is normally greatly enhanced by IFNγ, a cytokine produced mainly after onset of adaptive immunity. However, adaptive immunity is unable to provide sterilizing immunity against mycobacteria, suggesting that mycobacteria have evolved virulence strategies to inhibit the bactericidal effect of IFNγ-signalling in macrophages. Still, the host-pathogen interactions and cellular mechanisms responsible for this feature have remained elusive. We demonstrate that the ESX-1 type VII secretion systems of Mycobacterium tuberculosis and Mycobacterium marinum exploit type I IFN-signalling to promote an IL-12(low) /IL-10(high) regulatory macrophage phenotype characterized by secretion of IL-10, IL-27 and IL-6. This mechanism had no impact on intracellular growth in the absence of IFNγ but suppressed IFNγ-mediated autophagy and growth restriction, indicating that the regulatory phenotype extends to function. The IFNγ-refractory phenotype was partly mediated by IL-27-signalling, establishing functional relevance for this downstream cytokine. These findings identify a novel macrophage-modulating function for the ESX-1 secretion system that may contribute to suppress the efficacy of adaptive immunity and provide mechanistic insight into the antagonistic cross talk between type I IFNs and IFNγ in mycobacterial infection.

Outcome of tuberculosis treatment in HIV-positive adults diagnosed through active versus passive case-finding.

BACKGROUND: The World Health Organization strongly recommends regular screening for tuberculosis (TB) in HIV-positive individuals. OBJECTIVE: To compare the outcome of anti-tuberculosis treatment (ATT) in HIV-positive adults diagnosed with TB through active case-finding (ACF) or passive case-finding (PCF). DESIGN: Antiretroviral therapy (ART)-naïve adults diagnosed with TB were included from two prospective cohort studies conducted in Ethiopia between September 2010 and March 2013. The PCF cohort was based at out-patient TB clinics, whereas participants in the ACF cohort were actively screened for TB by bacteriological sputum testing (smear microscopy, Xpert MTB/RIF assay, and liquid culture) without pre-selection on the basis of symptoms and signs. Outcomes of ATT were compared between participants in the two cohorts; characteristics at diagnosis and predictors of adverse outcomes were analysed. RESULTS: Among 439 TB/HIV co-infected participants, 307 and 132 belonged to PCF and ACF cohorts, respectively. Compared with the ACF participants, hemoptysis, conjunctival pallor, bedridden status, and low mid upper-arm circumference (MUAC) were significantly more common in participants identified through PCF. Sputum smear-positivity rates among pulmonary TB cases were 44.2% and 21.1% in the PCF and ACF cohorts, respectively (p<0.001). Treatment success was ascertained in 247 (80.5%) of the participants in the PCF cohort and 102 (77.2%) of the participants in the ACF cohorts (p=0.223). Low MUAC (p=0.001) independently predicted mortality in the participants in both cohorts. CONCLUSION: Although patients identified through ACF had less advanced TB disease, ATT outcome was similar to the patients identified through PCF. To achieve a better outcome, case management in ACF strategy should be strengthened through enhanced patient-centred counselling and adherence support.

Intensified tuberculosis case-finding in HIV-positive adults managed at Ethiopian health centers: diagnostic yield of Xpert MTB/RIF compared with smear microscopy and liquid culture.

BACKGROUND: Detection of active tuberculosis (TB) before antiretroviral therapy (ART) initiation is important, but optimal diagnostic methods for use in resource-limited settings are lacking. We assessed the prevalence of TB, evaluated the diagnostic yield of Xpert MTB/RIF in comparison with smear microscopy and culture, and the impact of Xpert results on clinical management in HIV-positive adults eligible for ART at health centers in a region of Ethiopia. METHODS: Participants were prospectively recruited and followed up at 5 health centers. Trained nurses collected data on socio-demographic characteristics, medical history and symptoms, and performed physical examination. Two paired morning sputum samples were obtained, and lymph node aspirates in case of lymphadenopathy. Diagnostic yield of Xpert MTB/RIF in sputum was compared with smear microscopy and liquid culture. RESULTS: TB was diagnosed in 145/812 participants (17.9%), with bacteriological confirmation in 137 (16.9%). Among bacteriologically confirmed cases, 31 were smear-positive (22.6%), 96 were Xpert-positive (70.1%), and 123 were culture-positive (89.8%). Xpert MTB/RIF increased the TB detection rate by 64 cases (47.4%) compared with smear microscopy. The overall sensitivity of Xpert MTB/RIF was 66.4%, and was not significantly lower when testing one compared with two samples. While Xpert MTB/RIF was 46.7% sensitive among patients with CD4 cell counts >200 cells/mm(3), this increased to 82.9% in those with CD4 cell counts ≤100 cells/mm(3). Compared with Xpert-positive TB patients, Xpert-negative cases had less advanced HIV and TB disease characteristics. CONCLUSIONS: Previously undiagnosed TB is common among HIV-positive individuals managed in Ethiopian health centers. Xpert MTB/RIF increased TB case detection, especially in patients with advanced immunosuppression. An algorithm based on the use of a single morning sputum sample for individuals with negative sputum smear microscopy could be considered for intensified case finding in patients eligible for ART. However, technical and cost-effectiveness issues relevant for low-income countries warrant further study.

Risk of inflammatory bowel disease following Bacille Calmette-Guérin and smallpox vaccination: a population-based Danish case-cohort study.

BACKGROUND: Childhood immunology has been suggested to play a role in development of inflammatory bowel disease (IBD) based on the studies of childhood vaccinations, infections, and treatment with antibiotics. Bacille Calmette-Guérin (BCG) and smallpox vaccinations were gradually phased-out in Denmark for children born between 1965 and 1976, hence allowing the study of subsequent risk of Crohn's disease and ulcerative colitis in a unique prospective design. METHODS: The Copenhagen School Health Records Register contains detailed documentation of vaccination. Among the background cohort of individuals born between 1965 and 1976 (N = 47,622), cases with Crohn's disease (n = 218) and ulcerative colitis (n = 256) were identified through linkage to the Danish National Patient Registry. The vaccination status of the cases was compared with that of a subcohort (n = 5741) of the background cohort and analyzed in a case-cohort design. RESULTS: No difference in risk of IBD was observed between individuals vaccinated and unvaccinated with BCG (hazard ratio = 0.95; 95% confidence interval, 0.75-1.19) or smallpox vaccine (hazard ratio = 1.01; 95% confidence interval, 0.77-1.32). This was also the case for Crohn's disease and ulcerative colitis separately. However, BCG given before 4 months of age may decrease the risk of IBD (hazard ratio = 0.43; 95% confidence interval, 0.20-0.93). CONCLUSIONS: This prospective long-term case-cohort study shows that BCG and smallpox vaccination do not cause IBD later in life. These findings are important for the etiological understanding of IBD and of clinical importance because BCG is still one of the most commonly used childhood vaccinations, smallpox vaccine has been reintroduced in the U.S. military, and both vaccines may be used as vectors in new vaccines.

Human papillomavirus typing in reporting of condyloma.

BACKGROUND: Monitoring of condylomas is an early evidence of population effectiveness of human papillomavirus (HPV) vaccination programs. If reporting could include HPV typing, the contribution by vaccine HPV types to condyloma burden could be monitored. METHODS: A sentinel site for reporting of condyloma including HPV typing was established at the Centre for Sexual Health in Malmö, Sweden. In 2006 to 2009, when there were few HPV vaccines, 621 subjects with condyloma were reported and HPV genotyped. RESULTS: Ninety-four percent of the condylomas contained genital HPV types. Thirty-five different genital HPV types were identified, with HPV6 (62%), HPV16 (13%), and HPV11 (10%) being the most common. At least 1 of the 4 HPV types in the HPV6/11/16/18 vaccine was detected in 77%. High-risk HPV types were more common in females (45%) than among males (27%) (odds ratio, 1.9; confidence interval, 1.3-2.8). Extended testing among subjects initially negative for HPV found 21 patients with cutaneous types of HPV, including a novel type (HPV153). CONCLUSIONS: This report provides a baseline distribution of HPV types in condylomas before the introduction of an HPV vaccination program in this population. Human papillomavirus typing is feasible in routine condyloma reporting.

A case of Mycobacterium goodii prosthetic valve endocarditis in a non-immunocompromised patient: use of 16S rDNA analysis for rapid diagnosis.

BACKGROUND: Mycobacterium goodii is a rare cause of significant infection. M. goodii has mainly been associated with lymphadenitis, cellulitis, osteomyelitis, and wound infection. CASE PRESENTATION: A case of a 76-year-old Caucasian female is presented. The patient developed a prosthetic valve endocarditis caused by M. goodii. She had also suffered from severe neurological symptoms related to a septic emboli that could be demonstrated as an ischemic lesion found on CT of the brain. Transesophageal echocardiography verified a large vegetation attached to the prosthetic valve. Commonly used blood culture bottles showed growth of the bacteria after 3 days. CONCLUSIONS: Although M. goodii is rarely involved in these kinds of severe infections, rapidly growing mycobacteria should be recognized during conventional bacterial investigations and identified by molecular tools such as analysis of 16S rDNA. Species identification of nontuberculous mycobacteria is demanding and is preferably done in collaboration with a mycobacterial laboratory. An early diagnosis provides the opportunity for adequate treatment. In the present case, prolonged antimicrobial treatment and surgery with replacement of the prosthetic valve was successful.

Swedish moist snuff accelerates gastric cancer development in Helicobacter pylori-infected wild-type and gastrin transgenic mice.

The Swedish variant of moist oral smokeless tobacco (snus) is popular in Sweden and Norway, banned from sale within the European Union and is currently being introduced in USA. The aim of the present study was to determine if snus is carcinogenic to the stomach, particularly in Helicobacter pylori (H.P.)-infected hosts at increased risk for gastric cancer development. Snus (Generaltrade mark; Swedish Match, Sweden) was mixed with powdered standard mouse chow at a concentration of 5-9% (wt/wt) and given to wild-type (WT, FVB) and gastrin transgenic (INS-GAS, FVB) mice for 6 months with or without H.P. (strain 67:21, CagA+, VacA+) infection. At necropsy, pathological evaluation of stomachs from uninfected snus-treated WT mice showed mild morphological changes, whereas 50% snus-treated INS-GAS mice developed carcinoma in situ (CIS), compared with 25% not exposed to snus. When snus was given to H.P.-infected mice, 9 of 17 WT mice developed CIS with intramucosal invasion, and the remaining 8 of 17 WT mice developed high-grade dysplasia (score >1.5) that was associated with increased gastritis, epithelial defects, oxyntic atrophy, hyperplasia and intestinal metaplasia. Twelve of 12 H.P.-infected INS-GAS mice developed CIS with intramucosal invasion and submucosal herniation. We suggest that snus is a potential gastric carcinogen in mice. The development of CIS was associated with increased rates of the epithelial cell proliferation and apoptosis, common features of gastric carcinogenesis.

Gastric bypass surgery does not increase susceptibility to Helicobacter pylori infection in the stomach of rat or mouse.

Gastric bypass is a clinical option for obesity surgery. An increased susceptibility to Helicobacter pylori infection in the bypassed stomach has been speculated. The aim of the present study was to examine the susceptibility of the bypassed stomach to H. pylori infection in rats and mice. Adult Sprague-Dawley and Wistar rats and NMRI mice were subjected to either gastric bypass or laparotomy only as control. The animals were inoculated with the CagA- and VacA- positive H. pylori strain 67/21 (not mouse-adapted) in the first experiment and with 9 additional isolates in the second, by injection into the bypassed stomach or the control stomach during surgery. The stomach of each animal was collected for H. pylori culture 2-3 weeks later. While all the rats were H. pylori negative, 54% of gastric bypassed mice and 75% of controls were positive (P = 0.4). We conclude that susceptibility to H. pylori infection in the stomach is not increased by gastric bypass surgery.