In-vitro activity of rifabutin against rifampicin-resistant Mycobacterium tuberculosis isolates with known rpoB mutations

The relationship between resistance to rifampicin and rifabutin and genetic alterations in the rpoB gene of 41 rifampicin-resistant isolates of Mycobacterium tuberculosis was evaluated. Although 35 isolates with rifampicin MICs > or = 32 mg/L were also rifabutin-resistant, six isolates with rifampicin MICs of 2-16 mg/L were susceptible to rifabutin (MIC < or = 0.5 mg/L). Mutations Asp516Val, Asp516Tyr, Leu533Pro and the double mutation Met515Ile and Leu533Pro influenced susceptibility to rifampicin, but not to rifabutin. All mutations at codons 531 and 526, except one isolate with a His526Cys mutation, correlated with resistance to both compounds.     

Incarceration and the acquired immunodeficiency syndrome: Autopsy results in Texas prison inmates

The Texas Department of Criminal Justice (TDCJ) houses many subjects with acquired immunodeficiency syndrome (AIDS) who receive medical care in a comprehensive AIDS treatment center. In this case-control autopsy survey, we compared pathological outcomes of TDCJ inmates treated at the center (n = 155) with nonincarcerated patients who died during the same period (n = 155). Using multiple regression analysis and a proportional hazards model, survival time in the prisoners was equivalent to that in the controls. With few exceptions, the prevalences of opportunistic viral, fungal, protozoal, and bacterial infections contributing to mortality were equivalent between groups. Mycobacterium tuberculosis was isolated more frequently in the inmates, and M avium intracellulare was isolated less frequently (P < .0001). The inmates had a higher prevalence of bacterial infection of the central nervous system (CNS) (9.1% v 1.4%; P < .006); half of all CNS bacterial infections were caused by M tuberculosis. Inmates had significantly lower prevalences of vacuolar myelopathy (P < .006) and severe wasting disease (P < .0009). We conclude that survival of prison inmates with AIDS treated in a comprehensive AIDS treatment center was equivalent to that of nonincarcerated subjects with AIDS. Prevalences of certain complications of AIDS differed in the inmates, showing that the prison environment influenced some of the underlying causes of AIDS morbidity and mortality.     

Comparative cytological study of lymph node tuberculosis in HIV-infected individuals and in patients with diabetes in a developing country

Tuberculosis (TB) is a common infection affecting patients with human immunodeficiency virus (HIV) and diabetes mellitus (DM). With the increasing incidence of HIV infection and DM in a developing country like India, TB is definitely on the rise. In a given population, one expects to see these three diseases in varying combinations, such as HIV and TB, DM and TB, HIV and DM with TB. In such combinations TB may lack the characteristic clinical and histological picture due to the associated depressed cell-mediated immunity seen in both diseases and TB may have an unusual clinical presentation and cytology picture. In this retrospective study of 36 months, from January 1997 to December 1999, 109 cases diagnosed cytologically as tuberculous lymphadenitis and tested for HIV infection and investigated as well for DM were selected. Forty-six (42%) were nondiabetic HIV patients, 13 (12%) were non-HIV DM patients, and 50 (46%) had TB without HIV infection or DM. The coexistence of both HIV and DM was not noted. The cytomorphological characteristics supplemented by culture studies of each of these three groups were compared in detail and based on these four cytological patterns, Pattern 1, Pattern 2, Pattern 3, and Pattern 4 emerged and were characterized. This study highlights the usefulness of cytomorphology of the lymph nodes to characterize the cytopathological profile of TB in both HIV and DM, which have many clinical and immunological similarities, and indirectly postulate the extent of immune suppression and evolve effective strategies in the management of coexisting diseases. Such a comparative study has not been carried out in the past.     

Public health impact of isoniazid-resistant Mycobacterium tuberculosis strains with a mutation at amino-acid position 315 of katG: a decade of experience in The Netherlands

A previous limited study demonstrated that Mycobacterium tuberculosis isolates with a mutation at amino-acid position 315 of katG (Delta315) exhibited high-level resistance to isoniazid and were more frequently resistant to streptomycin. In the present study, isoniazid-resistant M. tuberculosis isolates from 8,332 patients in The Netherlands (1993-2002) were screened for the Delta315 mutation. Isoniazid resistance was found in 592 (7%) isolates, of which 323 (55%) carried Delta315. IS6110 restriction fragment length polymorphism analysis showed that Delta315 isolates occurred in clusters, suggesting recent transmission, at the same frequency as isoniazid-susceptible isolates. In contrast, other isoniazid-resistant isolates clustered significantly less frequently. Delta315 isolates were high-level isoniazid-resistant, streptomycin-resistant and multidrug-resistant significantly more often, and may have a greater impact on public health, than other isoniazid-resistant isolates.     

结核分枝杆菌联合DNA疫苗初免-BCG加强的免疫效果观察

目的:研究并比较结核分枝杆菌免疫保护性抗原DNA(Ag85A和ESAT-6)疫苗联合免疫,BCG免疫以及联合DNA疫苗初免-BCG加强免疫等不同的免疫策略,诱导免疫应答效果观察.方法:健康雌性BALB/c小鼠24只,随机分成PBS 阴性对照组,DNA初免-BCG异源加强组,DNA(Ag85A和ESAT-6)初免DNA同源加强组和BCG阳性对照组,共进行3次免疫,初免2次,最后1次加强,间隔2周1次.PBS组3次均注射PBS 溶液;DNA/BCG组以质粒DNA免疫2次,最后1次以BCG加强免疫;DNA/DNA组3次均以质粒DNA进行免疫;BCG组则注射PBS溶液2次后以BCG免疫.末次免疫后4、6、8周分别分离血清测定总IgG水平,同时分离小鼠脾细胞,体外经TB-PPD刺激后进行淋巴细胞增殖实验(XTT法)并测定脾细胞培养上清中IFN-γ和IL-4水平.结果:DNA/BCG、DNA/DNA、BCG组体外经TB-PPD刺激后均检测到特异性IgG抗体产生,3组平均效价为1:120、1:160、1:80,DNA/DNA组的抗体效价高于另外2组;小鼠脾细胞体外经TB-PPD刺激后,均能产生特异性淋巴细胞增殖并诱生较强的IFN-γ反应,其中DNA/BCG组IFN-γ的分泌水平高于DNA/DNA组和BCG组(P<0.05).结论:联合DNA疫苗初免-BCG加强的免疫策略能在小鼠体内诱导较强的特异性细胞免疫反应,产生高水平的IFN-γ.     

Detection of mutations in Mycobacterium tuberculosis genome determining resistance to fluoroquinolones by hybridization on biological microchips

We developed a method of identification of Mycobacterium tuberculosis with simultaneous evaluation of the sensitivity to fluoroquinolones on a biological microchip array. The method of multiplex two-staged PCR followed by hybridization of a biochip makes it possible to detect 8 mutant variants of gyrA gene occurring in fluoroquinolone-resistant strains (∼85% all resistant forms) within 1 day. Using this method we analyzed 107 cultures isolated from patients with tuberculosis and 78 sputum samples. Mutations in gyrA gene were detected in 48 (92%) resistant strains. Natural S95T polymorphism in gyrA gene was detected in all resistant and in 76% sensitive strains. The sensitivity and specificity of the proposed method calculated on the basis of the analysis of sputum samples (n=78) were 94 and 100%, respectively. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 1, pp. 115–120, January, 2008     

HIV coinfections with tuberculosis among HIV-1 infected individuals in old cross river state,Nigeria

ABSTRACT

Human immunodeficiency virus (HIV) and Tuberculosis (TB) are two main global public health threats that dent development in low and middle-income countries. This study evaluated the HIV/TB co-infection rate among HIV-1 infected individuals in old Cross River State, Nigeria. A total of 417 HIV-infected individuals participated in this study, 241 (57.8%) from Calabar, Cross River State, Nigeria and 176 (42.2%) from Uyo, Akwa-Ibom State, Nigeria. The age range of the 417 HIV-1 positive individuals who participated in the study was 4–72 years with an average age of 39.1 years. Plasma samples were analyzed for HIV and TB using fourth-generation Enzyme-Linked immunosorbent Assay. The CD4 count was enumerated using the Partec CyFlow® Counter. Plasma viral loads (PVL) were determined using the Abbott Real-Time HIV-1 assay. Results showed that 230 (55.2%) of the participants were in the 31–45 years age range. The majority (67.4%) of the HIV-1 infected individuals were females and 32.6% were males. An overall prevalence of HIV/TB coinfection in Old Cross River State, Nigeria was 1.4%, with Akwa Ibom State (0.6%) and Cross River State (1.2%). A higher prevalence of HIV/TB coinfection was observed among females (1.8%) than in males (0.7%). Higher prevalences of HIV/TB coinfections was observed in patients above 45 years of age (2.2%), married (2.3%), tertiary education (1.8%) followed by those with secondary education (1.4%), traders and civil servants (3.1%), patients with CD4 counts 200–349 and ≥500 cells/μl (1.9%), and those with viral load <40 copies/mL (2.7%). This study confirmed the presence of HIV/TB co-infection in old Cross River State, Nigeria. Although the prevalence rate of HIV/TB coinfection was low, its presence alone among HIV-1 infected individuals makes it a major source of concern. This finding highlights the need for a well-structured approach to the management of co-infection, and this includes both the social and medical aspects of the problem.     

结核分枝杆菌Ag85B基因疫苗免疫保护作用的初步研究

目的:研究编码结核分枝杆菌分泌蛋白Ag85B的基因疫苗pTB30m和pTB30s对免疫动物的保护作用。方法:以基因疫苗pTB30m和pTB30s肌注免疫BALB/c小鼠。免疫完成6 wk后,用5×105 CFU的MTB H37Rv毒株经小鼠尾静脉攻击感染。同时用尼龙毛柱分离基因免疫BALB/c小鼠的T细胞,并以5×106 T细胞/只小鼠过继免疫正常BALB/c小鼠,立即用105 CFU的MTB毒株经小鼠尾静脉攻击感染。4 wk后分别计数脾脏中的细菌负荷。结果:与生理盐水对照组相比较,pTB30m及pTB30s质粒免疫组BALB/c小鼠脾脏中的细菌负荷均减少,分别为0.645(log10 CFU,P<0.01)和0.839(log10CFU,P<0.001);而空质粒对照组小鼠脾脏中的细菌负荷减少较少。经质粒pTB30m和pTB30s免疫的BALB/c小鼠的T细胞,过继免疫的正常BALB/c小鼠,对攻击感染的MTB H37Rv毒株在脾脏中的增殖具有部分抑制作用。结论:pTB30s免疫的BALB/c小鼠,对MTB H37 Rv毒株攻击的保护作用优于pTB30m质粒免疫,有望进一步用于结核病的防治研究。     

High antibody levels to the mycobacterial fibronectin-binding antigen of 30-31 kD in tuberculosis and lepromatous leprosy.

Immunoblot assays showed that mycobacterial fibronectin-binding antigens are important targets of the humoral immune response in tuberculosis and leprosy. Using culture filtrate antigens of Mycobacterium tuberculosis, strong reactivity with the fibronectin-binding of 30-31 kD (Fn 30-31) was demonstrated in 55.9% of tuberculosis sera and in 56.5% of lepromatous leprosy sera. Sera from patients with tuberculoid leprosy and control sera gave very weak binding. Reactivity of tuberculosis and lepromatous leprosy sera with the fibronectin-binding antigen of 58-60 kD (Fn 58-60) was less conspicuous. The ability to react with fibronectin of the antigens of 58-60 and 30-31 kD was demonstrated by parallel labelling with a fibronectin-biotin conjugate. Fn 30-31 was purified to homogeneity by a two-step procedure and used for ELISA. Positive titres were found in 63% out of 65 tuberculosis sera and in 60.5% out of 43 lepromatous leprosy sera. Antibody titres in lepromatous leprosy sera were higher than in tuberculosis sera. Our observations indicate indirectly that M. leprae possess a highly immunogenic molecule homologous to M. tuberculosis Fn 30-31, which elicits a high antibody response in lepromatous leprosy but not in tuberculoid leprosy. In this investigation, direct evidence for the presence of this antigen in M. leprae was obtained by immunochemistry of lepromatous leprosy lesions with a monospecific antibody raised against M. tuberculosis Fn 30-31.     

The effect of passive smoking on asthma symptoms,atopy,and airway hyperresponsiveness in schoolchildren

Passive smoking is a major cause of respiratory morbidity, and is associated with increased bronchial responsiveness in children. To evaluate the effect of smoking by a parent on asthma symptoms, atopy, and airway hyperresponsiveness (AHR), we conducted a cross-sectional survey of 503 schoolchildren that involved questionnaires, spirometry, allergy testing, and a bronchial challenge test. If the PC20 methacholine was less than 16 mg/mL, the subject was considered to have AHR. The prevalence of a parent who smoked was 68.7%. The prevalence of AHR was 45.0%. The sensitization rate to common inhalant allergens was 32.6%. Nasal symptoms such as rhinorrhea, sneezing, nasal itching, and nasal obstruction were present in 42.7%. Asthma symptoms such as cough and wheezing were present in 55.4%. The asthma symptoms were significantly more prevalent in children who had a parent who smoked than in those whose parents did not. The nasal symptoms, atopy, and AHR did not differ according to whether a parent smoked. In a multiple logistic regression model, the asthma symptoms and atopy were independently associated with AHR, when adjusted for confounding variables. Passive smoking contributed to asthma symptoms in schoolchildren and was not an independent risk factor of airway hyperresponsiveness in an epidemiological survey.