María Patricia Arbeláez

IFNγ Response to Mycobacterium tuberculosis, Risk of Infection and Disease in Household Contacts of Tuberculosis Patients in Colombia

Objectives Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNγ produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNγ levels in HHCs correlate with tuberculosis development. Methods A cohort of 2060 HHCs was followed for 2–3 years after exposure to a tuberculosis case. Besides TST, IFNγ responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination. Results Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNγ response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNγ responders to CFP-10 (HR 1.82 95% CI 0.79–4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNγ producers was observed (trend Log rank p = 0.007). Discussion CFP-10-induced IFNγ production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high tuberculosis incidence amongst children supports administration of chemoprohylaxis to child contacts regardless of BCG vaccination.

Safety and immunogenicity of a killed Leishmania (L.) amazonensis vaccine against cutaneous leishmaniasis in Colombia: a randomized controlled trial

The safety and immunogenicity of an intramuscular (i.m.) and intradermal (ID) formulation of autoclaved Leishmania (Leishmania) amazonensis vaccine was evaluated in 296 volunteers in a randomized, placebo-controlled, double-blind trial in Colombia. There were 4 vaccination groups: i.m. vaccine, i.m. placebo, ID vaccine, and ID placebo. The ID formulations were mixed with BCG as adjuvant at the time of injection. For each group, 3 vaccinations were given with a 20-day interval between injections, and adverse events were monitored at 20 min, and at 2, 7 and 21 days after each injection. BCG-induced adverse reactions resulted in cancellation of the third vaccine administration in the ID groups. Antibody titres did not differ significantly between the groups. Montenegro skin-test conversion was achieved by 86.4% and 90% of the i.m. vaccine group and by 25% and 5% of the i.m. placebo group 80 days and 1 year after vaccination, respectively. A significant increase in mean Leishmania-antigen lymphocyte proliferation indexes was observed after i.m. vaccine immunization, but not after i.m. placebo immunization, 80 days and 1 year after vaccination. Significant levels of IFN gamma but not IL-10 were observed 1 year after vaccination in the i.m. vaccine group compared to the i.m. placebo group. The good safety profile and evidence of Th1 immune reactions due to i.m. vaccination in this phase-I/II study suggest that a population-based phase-III efficacy trial of the i.m. vaccine should be initiated.

Evidence for a role of the NOS1AP (CAPON) gene in schizophrenia and its clinical dimensions: an association study in a South American population isolate.

Background/Aims: Recent studies have implicated a region on chromosome 1q21-23, including the NOS1AP gene, in susceptibility to schizophrenia. However, replication studies have been inconsistent, a fact that could partly relate to the marked psychopathological heterogeneity of schizophrenia. The aim of this study is to evaluate association of polymorphisms in the NOS1AP gene region to schizophrenia, in patients from a South American population isolate, and to assess if these variants are associated with specific clinical dimensions of the disorder. Methods: We genotyped 24 densely spaced SNPs in the NOS1AP gene region in a schizophrenia trio sample. The transmission disequilibrium test (TDT) was applied to single marker and haplotype data. Association to clinical dimensions (identified by factor analysis) was evaluated using a quantitative transmission disequilibrium test (QTDT). Results: We found significant association between eight SNPs in the NOS1AP gene region to schizophrenia (minimum p value = 0.004). The QTDT analysis of clinical dimensions revealed an association to a dimension consisting mainly of negative symptoms (minimum p value 0.001). Conclusions: Our findings are consistent with a role for NOS1AP in susceptibility to schizophrenia, especially for the ‘negative syndrome’ of the disorder.

High Incidence of Tuberculosis, Low Sensitivity of Current Diagnostic Scheme and Prolonged Culture Positivity in Four Colombian Prisons. A Cohort Study

Objective To determine the incidence of pulmonary tuberculosis (TB) in inmates, factors associated with TB, and the time to sputum smear and culture conversion during TB treatment. Methods Prospective cohort study. All prisoners with respiratory symptoms (RS) of any duration were evaluated. After participants signed consent forms, we collected three spontaneous sputum samples on consecutive days. We performed auramine-rhodamine staining, culturing with the thin-layer agar method, Löwestein-Jensen medium and MGIT, susceptibility testing for first-line drugs; and HIV testing. TB cases were followed, and the times to smear and culture conversion to negative were evaluated. Results Of 9,507 prisoners held in four prisons between April/30/2010 and April/30/2012, among them 4,463 were screened, 1,305 were evaluated for TB because of the lower RS of any duration, and 72 were diagnosed with TB. The annual incidence was 505 cases/100,000 prisoners. Among TB cases, the median age was 30 years, 25% had <15 days of cough, 12.5% had a history of prior TB, and 40.3% had prior contact with a TB case. TB-HIV coinfection was diagnosed in three cases. History of prior TB, contact with a TB case, and being underweight were risk factors associated with TB. Overweight was a protective factor. Almost a quarter of TB cases were detected only by culture; three cases were isoniazid resistant, and two resistant to streptomycin. The median times to culture conversion was 59 days, and smear conversion was 33. Conclusions The TB incidence in prisons is 20 times higher than in the general Colombian population. TB should be considered in inmates with lower RS of any duration. Our data demonstrate that patients receiving adequate anti-TB treatment remain infectious for prolonged periods. These findings suggest that current recommendations regarding isolation of prisoners with TB should be reconsidered, and suggest the need for mycobacterial cultures during follow-up.

Population Structure among Mycobacterium tuberculosis Isolates from Pulmonary Tuberculosis Patients in Colombia

Background Phylogeographic composition of M. tuberculosis populations reveals associations between lineages and human populations that might have implications for the development of strategies to control the disease. In Latin America, lineage 4 or the Euro-American, is predominant with considerable variations among and within countries. In Colombia, although few studies from specific localities have revealed differences in M. tuberculosis populations, there are still areas of the country where this information is lacking, as is a comparison of Colombian isolates with those from the rest of the world. Principal Findings A total of 414 M. tuberculosis isolates from adult pulmonary tuberculosis cases from three Colombian states were studied. Isolates were genotyped using IS6110-restriction fragment length polymorphism (RFLP), spoligotyping, and 24-locus Mycobacterial interspersed repetitive units variable number tandem repeats (MIRU-VNTRs). SIT42 (LAM9) and SIT62 (H1) represented 53.3% of isolates, followed by 8.21% SIT50 (H3), 5.07% SIT53 (T1), and 3.14% SIT727 (H1). Composite spoligotyping and 24-locus MIRU- VNTR minimum spanning tree analysis suggest a recent expansion of SIT42 and SIT62 evolved originally from SIT53 (T1). The proportion of Haarlem sublineage (44.3%) was significantly higher than that in neighboring countries. Associations were found between M. tuberculosis MDR and SIT45 (H1), as well as HIV-positive serology with SIT727 (H1) and SIT53 (T1). Conclusions This study showed the population structure of M. tuberculosis in several regions from Colombia with a dominance of the LAM and Haarlem sublineages, particularly in two major urban settings (Medellín and Cali). Dominant spoligotypes were LAM9 (SIT 42) and Haarlem (SIT62). The proportion of the Haarlem sublineage was higher in Colombia compared to that in neighboring countries, suggesting particular conditions of co-evolution with the corresponding human population that favor the success of this sublineage.

Molecular characterization of hepatitis c virus in multi-transfused Colombian patients

BackgroundHepatitis C virus (HCV) infects 170 million persons worldwide and is a public health problem. Considering that HCV is principally transmitted by exposure to infected blood, multi-transfused patients constitute one of the most important risk groups in developing countries. To explore the dynamics of this infection in Colombia, we performed a study to determine the genotypes of HCV in a cohort of multi-transfused patients.ResultsThe serum samples from patients positive for anti-HCV were evaluated for HCV RNA by nested-PCR of the 5’untranslated region (5’UTR). Viral genotype was determined by RFLP and/or automated sequencing. HCV subtype 1b was found in eight cases (66.7%) and subtype 1a in two cases (16.7%); seven isolates of subtype 1b were obtained from patients who had received the first transfusion before 1986. Either genotypes 2b (8.3%) or 3a (8.3%) were found in the remaining positive specimens.ConclusionsThis is the first HCV genotyping study developed in multi-transfused patients in Colombia where HCV subtype 1b was the most prevalent. The mutation G235A in the 5’UTR of three isolates generated an additional restriction site and an RFLP pattern different from those previously described for genotype 1.

Prevalence of specific herpes simplex virus-2 antibodies and associated factors in women of a rural town of Colombia

There is lack of age-specific seroprevalence surveys and identification of factors associated with herpes simplex virus type-2 seropositivity (HSV-2) in rural populations in Colombia. A random sample of 869 women was interviewed about socio-demographic aspects, sexual and reproductive history. Antibodies to HSV-2 were determined by a specific type immunoenzymatic technique (ELISA). Participants had a mean age of 38±16.1 years, 67% were married, 60% monogamous and 47% reported use of condoms. HSV-2 seroprevalence was 19.1% (95% CI: 16.6-21.9) and it was strongly associated with increasing age (Ptrend<0.001). In the logistic regression analysis, women who reported between two or three lifetime sexual partners (OR=2.4; 95% CI: 1.5-3.7), >31 years of sexual activity with regular or occasional sexual partners (OR=4.3; 95% CI: 1.2-15.7) and not using condoms with regular sexual partners (OR=2.1; 95% CI: 1.4-3.3) were more likely to be HSV-2 seropositive. The overall seroprevalence rate of women of Pueblorrico, Colombia, is lower than that reported in other Latin American countries especially in women>45 years. The difference may be explained by higher prevalence of condom use in this population or lower exposure to herpes infection in male as well as females in the past.

High prevalence and risk factors associated with latent tuberculous infection in two Colombian prisons.

SETTING Two prisons in Medellín and Itagüí, Colombia. OBJECTIVE To determine the prevalence of tuberculin skin test (TST) positivity in prisoners and the annual risk of tuberculous infection (ARTI), to identify risk factors associated with a positive result, and to describe progression to active disease. DESIGN Cross-sectional study. Inmates were included if time of incarceration was ⩾1 year and excluded if subjects had had previous or active tuberculosis (TB), or conditions that could hamper TST administration or interpretation. RESULTS We screened 1014 inmates. The overall prevalence of TST positivity was 77.6%. The first TST administration resulted in 66% positivity, and the second TST an additional 11.6%. In Prison One, the ARTI was 5.09% in high TB incidence cell blocks and 2.72% in low TB incidence blocks. In Prison Two, the ARTI was 2.77%. Risk factors associated with TST positivity were history of previous incarceration and length of incarceration. Among all those included in the study, four individuals developed active pulmonary TB. CONCLUSION Prevalence of TST positivity in prisoners and the ARTI were higher than in the general population, but differed between prisons; it is important to apply a second TST to avoid an overestimation of converters during follow-up.

Hepatitis B and Hepatitis C Infection Biomarkers and TP53 Mutations in Hepatocellular Carcinomas from Colombia

Hepatocellular Carcinoma (HCC) is a leading cause of cancer-related death worldwide. Globally, the most important HCC risk factors are Hepatitis B Virus (HBV) and/or Hepatitis C Virus (HCV), chronic alcoholism, and dietary exposure to aflatoxins. We have described the epidemiological pattern of 202 HCC samples obtained from Colombian patients. Additionally we investigated HBV/HCV infections and TP53 mutations in 49 of these HCC cases. HBV biomarkers were detected in 58.1% of the cases; HBV genotypes F and D were characterized in three of the samples. The HCV biomarker was detected in 37% of the samples while HBV/HCV coinfection was found in 19.2%. Among TP53 mutations, 10.5% occur at the common aflatoxin mutation hotspot, codon 249. No data regarding chronic alcoholism was available from the cases. In conclusion, in this first study of HCC and biomarkers in a Colombian population, the main HCC risk factor was HBV infection.

Hepatitis E Virus Genotype 3 in Colombia: Survey in Patients with Clinical Diagnosis of Viral Hepatitis.

Background Hepatitis E virus is a major cause of outbreaks as well as sporadic hepatitis cases worldwide. The epidemiology of this enterically transmitted infection differs between developing and developed countries. The aims of this study were to describe HEV infection in Colombian patients and to characterize the genotype. Methods A prospective study was carried out on 40 patients aged over 15 with a clinical diagnosis of viral hepatitis, recruited from five primary health units in the city of Medellin, Colombia. Fecal samples obtained from the 40 consecutives cases were analyzed for HEV RNA using nested reverse transcription PCR for both ORF1 and ORF2-3. The amplicons were sequenced for phylogenetic analyses. Results Nine (22.5%) cases of HEV infection were identified in the study population. Three HEV strains obtained from patients were classified as genotype 3. No significant association was found between cases of Hepatitis E and the variables water drinking source, garbage collection system and contact with pigs. Conclusions This is the first prospective study of hepatitis E in Colombian patients. The circulation of the genotype 3 in this population is predictable considering the reports of the region and the identification of this genotype from pigs in the state of Antioquia, of which Medellin is the capital. Further studies are necessary to establish whether zoonotic transmission of HEV is important in Colombia.