Pediatric tuberculous meningitis: Model-based approach to determining optimal doses of the anti-tuberculosis drugs rifampin and levofloxacin for children

Pediatric tuberculous meningitis (TBM) is a highly morbid, often fatal disease. Standard treatment includes isoniazid, rifampin, pyrazinamide, and ethambutol. Current rifampin dosing achieves low cerebrospinal fluid (CSF) concentrations, and CSF penetration of ethambutol is poor. In adult trials, higher-dose rifampin and/or a fluoroquinolone reduced mortality and disability. To estimate optimal dosing of rifampin and levofloxacin for children, we compiled plasma and CSF pharmacokinetic (PK) and outcomes data from adult TBM trials plus plasma PK data from children. A population PK/pharmacodynamic (PD) model using adult data defined rifampin target exposures (plasma area under the curve (AUC)0-24 = 92 mg*h/L). Levofloxacin targets and rifampin pediatric drug disposition information were literature-derived. To attain target rifampin exposures, children require daily doses of at least 30 mg/kg orally or 15 mg/kg intravenously (i.v.). From our pediatric population PK model, oral levofloxacin doses needed to attain exposure targets were 19-33 mg/kg. Our results provide data-driven guidance to maximize pediatric TBM treatment while we await definitive trial results.

Diagnosis of tuberculous meningitis: challenges and promises

Tuberculosis (TB) which is caused by Mycobacterium tuberculosis infects primarily the lungs but it also affects other parts of the body. Tuberculous meningitis (TBM) is the most severe form of TB and has the highest mortality and morbidity rate compared to other forms of TB. It is common in young children and HIV-infected patients, but is also seen in adults. Despite anti-tuberculosis treatment, TBM is still a major cause of death and neurological sequelae as treatment given to the patients is often delayed. Early diagnosis is challenging due to the non-specific symptoms of TBM and the low number of tubercle bacilli in cerebrospinal fluid (CSF). Until now, there is no established diagnostic method that can rapidly detect M. tuberculosis in TBM patients with high sensitivity and specificity. The emergence of drug resistant M. tuberculosis strains further complicates the diagnosis and treatment regimen of TBM. This review summarizes challenges of the currently used diagnostic methods and the potential future use of molecular diagnostic methods for TBM.

Kinetics of T-cell-based assays on cerebrospinal fluid and peripheral blood mononuclear cells in patients with tuberculous meningitis

BACKGROUND/AIMS

The goal of this study was to monitor tuberculosis (TB)-specific T-cell responses in cerebrospinal fluid-mononuclear cells (CSF-MCs) and peripheral blood mononuclear cells (PBMCs) in patients with tuberculous meningitis (TBM) over the course of anti-TB therapy.

METHODS

Adult patients (≥ 16 years) with TBM admitted to Asan Medical Center, Seoul, South Korea, were prospectively enrolled between April 2008 and April 2011. Serial blood or CSF samples were collected over the course of the anti-TB therapy, and analyzed using an enzyme-linked immunosorbent spot (ELISPOT) assay.

RESULTS

Serial ELISPOT assays were performed on PBMCs from 17 patients (seven definite, four probable, and six possible TBM) and CSF-MC from nine patients (all definite TBM). The median number of interferon-gamma (IFN-γ)-producing T-cells steadily increased during the first 6 months after commencement of anti-TB therapy in PBMCs. Serial CSF-MC ELISPOT assays revealed significant variability in immune responses during the first 6 weeks of anti-TB therapy, though early increases in CSF-MC ELISPOT results were associated with treatment failure or paradoxical response.

CONCLUSIONS

Serial analysis of PBMCs by ELISPOT during the course of treatment was ineffective for predicting clinical response. However, increases in TB-specific IFN-γ-producing T-cells in CSF-MC during the early phase of anti-TB therapy may be predictive of clinical failure.

Modeling tuberculous meningitis in zebrafish using Mycobacterium marinum

Tuberculous meningitis (TBM) is one of the most severe extrapulmonary manifestations of tuberculosis, with a high morbidity and mortality. Characteristic pathological features of TBM are Rich foci, i.e. brain- and spinal-cord-specific granulomas formed after hematogenous spread of pulmonary tuberculosis. Little is known about the early pathogenesis of TBM and the role of Rich foci. We have adapted the zebrafish model of Mycobacterium marinum infection (zebrafish-M. marinum model) to study TBM. First, we analyzed whether TBM occurs in adult zebrafish and showed that intraperitoneal infection resulted in granuloma formation in the meninges in 20% of the cases, with occasional brain parenchyma involvement. In zebrafish embryos, bacterial infiltration and clustering of infected phagocytes was observed after infection at three different inoculation sites: parenchyma, hindbrain ventricle and caudal vein. Infection via the bloodstream resulted in the formation of early granulomas in brain tissue in 70% of the cases. In these zebrafish embryos, infiltrates were located in the proximity of blood vessels. Interestingly, no differences were observed when embryos were infected before or after early formation of the blood-brain barrier (BBB), indicating that bacteria are able to cross this barrier with relatively high efficiency. In agreement with this observation, infected zebrafish larvae also showed infiltration of the brain tissue. Upon infection of embryos with an M. marinum ESX-1 mutant, only small clusters and scattered isolated phagocytes with high bacterial loads were present in the brain tissue. In conclusion, our adapted zebrafish-M. marinum infection model for studying granuloma formation in the brain will allow for the detailed analysis of both bacterial and host factors involved in TBM. It will help solve longstanding questions on the role of Rich foci and potentially contribute to the development of better diagnostic tools and therapeutics.

Chronic meningitis in immunocompromised adult Ethiopians visiting Tikur Anbessa Teaching Hospital and Ye'huleshet Clinic from 2003-2004

BACKGROUND

Chronic meningitis is inflammation of the meninges where signs and symptoms develop and last for at least four weeks without alleviation. Little is known about the current etiology and incidence of the disease in adults living in developing countries.

OBJECTIVE

The objective of this study was to elucidate the most common etiologies of chronic meningitis in adult Ethiopian patients and give an aid in the empiric therapy.

METHODOLOGY

A total of 53 adult patients (median age 32 years) having chronic meningitis and who were admitted at Tikur Anbessa Teaching Hospital and Ye'huleshet Clinic, Addis Ababa, Ethiopia were recruited between 2003 and 2004. Of the 53 patients, bacteriological, molecular and immunological investigations were done for 52 of the study participants to detect Cryptococcus neoformans, Mycobacterium tuberculosis, Toxoplasma gondii, Brucella and Neisseria meningitides infections.

RESULTS

Forty eight of the participants were HIV positive and 15% (8/52) of the CSF were positive with Cryptococcal latex antigen detection test; in addition, M. tuberculosis DNA was detected using PCR from CSF ofpatients infew of the patients. Multiple infections were observed in studyparticipants with < 0.1 to 1 CD4 to CD8 ratio.

CONCLUSION

Chronic meningitis mostly occurred in HIV infected patients, where most of the infections were attributed to Cryptococcus neoformans whereas M. tuberculosis appeared secondary.

Stroke in patients with tuberculous meningitis in a low TB endemic country: an increasing medical emergency?

Stroke due to brain vascular disease is a serious complication of tuberculous meningitis (TBM). This study evaluated the frequency, clinical characteristics, risk factors and outcomes of patients with TBM complicated by stroke admitted to the Infectious Disease Clinic, University of Perugia Hospital, Italy from 1971 to 2010. Over four decades, 419 patients were admitted with tuberculosis, of these 30 (7.1%) were diagnosed with TBM: 20 definite, one probable and nine possible. Twenty-six were evaluable for stroke and six (23%) had stroke. The latter six had advanced stages of meningitis, two tested HIV positive, three HIV negative and in one HIV was not performed. Of seven patients without stroke tested for HIV, only one resulted positive. No differences were found regarding CSF cell count, sugar, protein, microscopy or growth of Mycobacterium tuberculosis among patients with or without stroke. The overall survival rate at discharge was 83% in patients with stroke and 95% in those without stroke. It was found that stroke can be frequent among patients with TBM and the presence of HIV infection might be associated with a higher rate of stroke. Further research is needed on these findings, especially in low TB endemic countries.

Cranial nerve palsy as a factor to differentiate tuberculous meningitis from acute bacterial meningitis

Tuberculous meningitis (TBM) and acute bacterial meningitis (ABM) cause substantial mortality and morbidity in both children and adults. Identification of poor prognostic factors at patient's admission could prepare physicians for more aggressive monitoring of patients with meningitis. The objective of this study was to determine the predictive value of neurological features to differentiate ABM and TBM. A retrospective study was conducted between patients affected with ABM or TBM admitted to three teaching hospitals during the last 14 years in Zahedan the central city of Sistan and Balouchestan province (Iran). The neurological features include seizure, level of consciousness, stroke, focal neurologic deficit and cranial nerve palsy at the time of admission. Mean age for patients with TBM and ABM were 41 ± 22.4 and 24 ± 18.5 years respectively. In univariate analysis, all measured variables revealed significant difference between ABM and TBM patients except for seizure episodes. Multivariate logistic regression analysis showed positive predictive effect of cranial nerve palsy (AOR=1.980, CI 95%: 1.161-3.376) on the diagnosis of TBM. In our study cranial nerve palsies was the most important neurological predictor factor to differentiate TBM from ABM.

Tuberculous meningitis: do modern diagnostic tools offer better prognosis prediction?

BACKGROUND

The British Medical Research Council (BMRC) staging has been extensively used to evaluate the disease severity and establish the approximate prognosis of tuberculous meningitis.

AIMS

This study aimed at analyzing the predictive accuracy for mortality and neurological sequelae of a set of clinical features, laboratory tests and imaging.

METHODS

We compared the British Medical Research Council (BMRC) staging with a new scoring proposal to predict the prognosis of patients with Central Nervous System Tuberculosis. Data from Ecuador was collected. A score was built using a Spiegelhalter and Knill-Jones method and compared with BMRC staging with a ROC curve.

RESULTS

A total of 213/310 patients (68.7%) were in BMRC stage II or III. Fifty-seven patients died (18.3%) and 101 (32.5%) survived with sequelae. The associated predictors were consciousness impairment (p = 0.010), motor deficit (p = 0.003), cisternal effacement (p = 0.006) and infarcts (p = 0.015). The new score based on these predictors yielded a larger area under the curve of 0.76 (95% CI: 0.70-0.82), but not significantly different from the BMRC (0.72: 95% CI: 0.65-0.77).

CONCLUSIONS

This modern score is easy to apply and could be a sound predictor of poor prognosis. However, the availability of modern tests did not improve the ability to predict a bad outcome.

Detection of Mycobacterium tuberculosis GlcB or HspX Antigens or devR DNA impacts the rapid diagnosis of tuberculous meningitis in children

Background

Tuberculous meningitis (TBM) is the most common form of neurotuberculosis and the fifth most common form of extrapulmonary TB. Early diagnosis and prompt treatment are the cornerstones of effective disease management. The accurate diagnosis of TBM poses a challenge due to an extensive differential diagnosis, low bacterial load and paucity of cerebrospinal fluid (CSF) especially in children.

Methodology/Principal Findings

We describe the utility of ELISA and qPCR for the detection of Mycobacterium tuberculosis (M. tb) proteins (GlcB, HspX, MPT51, Ag85B and PstS1) and DNA for the rapid diagnosis of TBM. CSF filtrates (n = 532) derived from children were classified as ‘Definite’ TBM (M. tb culture positive, n = 29), ‘Probable and Possible’ TBM (n = 165) and ‘Not-TBM’ including other cases of meningitis or neurological disorders (n = 338). ROC curves were generated from ELISA and qPCR data of ‘Definite’ TBM and Non-Tuberculous infectious meningitis (NTIM) samples and cut-off values were derived to provide ≥95% specificity. devR qPCR, GlcB, HspX and PstS1 ELISAs showed 100% (88;100) sensitivity and 96–97% specificity in ‘Definite’ TBM samples. The application of these cut-offs to ‘Probable and Possible’ TBM groups yielded excellent sensitivity (98%, 94;99) and specificity (98%, 96;99) for qPCR and for GlcB, HspX and MPT51 antigen ELISAs (sensitivity 92–95% and specificity 93–96%). A test combination of qPCR with GlcB and HspX ELISAs accurately detected all TBM samples at a specificity of ∼90%. Logistic regression analysis indicated that these tests significantly added value to the currently used algorithms for TBM diagnosis.

Conclusions

The detection of M. tb GlcB/HspX antigens/devR DNA in CSF is likely to improve the utility of existing algorithms for TBM diagnosis and also hasten the speed of diagnosis.

Tuberculous meningitis, an unusual presentation in a young lady

A 37-year-old Persian-speaking woman presented with epigastric pain, vomiting and non-specific frontal headache. Examination was unremarkable except for an isolated sixth nerve palsy found a few days after admission. Blood results were normal, as was the chest radiograph and the CT scan of the head. Initial cerebrospinal fluid (CSF) analysis revealed a significantly elevated protein level with reduced glucose, as well as CSF lymphocytosis. Tuberculosis (TB) meningitis was considered and she was commenced on anti-TB treatment before confirmation of the diagnosis. A full contact tracing was performed with regular follow-up with TB nurses. When she was seen in the clinic a month later, her symptoms had subsided completely.

[Tuberculous cranial pachymeningitis presenting with long-standing diffuse brain dysfunction]

We report a 59-year-old immunocompetent man presenting with slowly progressive gait unsteadiness, dysarthria, and clumsiness in writing over 6 months. There were bilateral pyramidal signs, pseudobulbar palsy, and attention deficits. Cerebrospinal fluid examination showed mild mononuclear pleocytosis, and magnetic resonance imaging revealed pachymeningeal pattern of contrast enhancement beneath the calvarium and the posterior cranial fossa. Interferon-gamma release assay in whole blood after stimulation by specific tuberculosis antigens was positive and repeat polymerase chain reaction assay detected Mycobacterium tuberculosis genome in the cerebrospinal fluid. After combination therapy with anti-tuberculous agents and corticosteroids, the patient's pachymeningitis regressed. Tuberculous cranial pachymeningitis may present with chronic diffuse brain dysfunction without headache, fever, or cranial nerve dysfunction.

In silico children and the glass mouse model: clinical trial simulations to identify and individualize optimal isoniazid doses in children with tuberculosis

Children with tuberculosis present with high rates of disseminated disease and tuberculous (TB) meningitis due to poor cell-mediated immunity. Recommended isoniazid doses vary from 5 mg/kg/day to 15 mg/kg/day. Antimicrobial pharmacokinetic/pharmacodynamic studies have demonstrated that the ratio of the 0- to 24-h area under the concentration-time curve (AUC(0-24)) to the MIC best explains isoniazid microbial kill. The AUC(0-24)/MIC ratio associated with 80% of maximal kill (80% effective concentration [EC(80)]), considered the optimal effect, is 287.2. Given the pharmacokinetics of isoniazid encountered in children 10 years old or younger, with infants as a special group, and given the differences in penetration of isoniazid into phagocytic cells, epithelial lining fluid, and subarachnoid space during TB meningitis, we performed 10,000 patient Monte Carlo simulations to determine how well isoniazid doses of between 2.5 and 40 mg/kg/day would achieve or exceed the EC(80). None of the doses examined achieved the EC(80) in ≥90% of children. Doses of 5 mg/kg were universally inferior; doses of 10 to 15 mg/kg/day were adequate only under the very limited circumstances of children who were slow acetylators and had disease limited to pneumonia. Each of the three disease syndromes, acetylation phenotype, and being an infant required different doses to achieve adequate AUC(0-24)/MIC exposures in an acceptable proportion of children. We conclude that current recommended doses for children are likely suboptimal and that isoniazid doses in children are best individualized based on disease process, age, and acetylation status.

Meningoencephalitis with Aspergillus and mycobacterium tuberculosis in a renal transplant recipient

OBJECTIVES

We report a case of central nervous system coinfection with 2 types of opportunistic organisms-Aspergillus and Mycobacterium tuberculosis-in a 33-year-old woman who underwent a renal transplant.

MATERIALS AND METHODS

She developed a high-grade fever and right-sided weakness 1 month after the transplant while on mycophenolate mofetil, prednisolone, and cyclosporine.

RESULTS

Brain magnetic resonance imaging revealed multiple mass lesions with peripheral ring enhancement. Colony-stimulating factor polymerase chain reaction was positive for Aspergillus and Mycobacterium tuberculosis.

CONCLUSIONS

Broad-spectrum antibiotics, antituberculous agents, and amphotericin were started. Unfortunately, the woman's condition deteriorated, and she died 2 weeks after admission to the hospital.

Predictors of mortality in tuberculous meningitis: a multivariate analysis of 160 cases

OBJECTIVE

To evaluate predictors of mortality in 160 patients with tuberculous meningitis (TBM).

DESIGN

One hundred and sixty patients with TBM who had been followed for 11 years in a tertiary referral centre hospital were assessed retrospectively. Features considered as predictors of mortality in TBM were studied by multivariate logistic regression to develop a prognostic rule.

RESULTS

Of 160 patients, 84% were in Stages II and III; 27 (17%) died. In univariate analysis, age, stage, altered sensorium, underlying comorbidities, pulmonary tuberculosis, leukocytosis and cerebrospinal fluid (CSF)/blood glucose < 0.30 and rise in CSF protein were associated with an increased risk of death. In multivariable analysis, age (OR 4.64, 95%CI 1.03-24.74, P = 0.046), altered sensorium (OR 8.62, 95%CI 1.25-110.0, P = 0.036), underlying comorbidity (OR 9.75, 95%CI 1.58-59.95, P = 0.014) and leukocytosis (OR 9.74, 95%CI 1.67-56.7, P = 0.011) were shown to be the best predictors of mortality in TBM.

CONCLUSIONS

We observed that TBM patients who died were more likely to be older and have altered mental status on admission, underlying comorbidities and leukocytosis than TBM patients who survived. These factors were the most important predictors of mortality from TBM.

Determination of polymerase chain reaction efficiency for diagnosis of tuberculous meningitis in Chelex-100 extracted DNA samples

SETTING

Polymerase chain reaction (PCR) offers great promise for the rapid, sensitive and specific diagnosis of tuberculous meningitis (TBM). However, the isolation of DNA of high quantity and quality from cerebrospinal fluid (CSF) samples is critical for successful PCR assays.

OBJECTIVE

To develop and use a single-tube method for the isolation of PCR-compatible DNA from Mycobacterium tuberculosis using Chelex-100 chelating resin, which does not require organic solvents or detergents.

DESIGN

The study focused on the standardisation of a suitable Chelex protocol and its evaluation in 32 CSF samples from TBM and non-TBM subjects. A simultaneous comparison was made with the conventional phenol/chloroform extraction method.

RESULT

PCR was found to be more sensitive, more rapid and less technically demanding with the Chelex protocol than the conventional phenol/chloroform extraction method (sensitivity 84.2% vs. 73.6%).

CONCLUSION

The single-tube method and the simplicity of the procedure permits early and reliable diagnosis of TBM and makes it an attractive method for routine laboratory assays.

Specific bacterial genotypes of Mycobacterium tuberculosis cause extensive dissemination and brain infection in an experimental model

Meningeal tuberculosis is a severe type of extrapulmonary disease, which is thought to begin with respiratory infection, followed by hematogenous dissemination and brain infection. Host genetic susceptibility factors and specific mycobacterial substrains could be involved in its development. From an epidemiological study in Colombia, we selected three Mycobacterium tuberculosis clinical strains isolated from the cerebrospinal fluid (CSF) of patients with meningeal tuberculosis, and used them to infect BALB/c mice through the intratracheal route. These strains showed a distinctive spoligotype pattern. The course of infection in terms of strain virulence (mice survival, bacillary loads in lungs), bacilli dissemination and extrapulmonary infection (bacilli loads in blood, brain, liver, kidney and spleen), and immune responses (cytokine expression determined by real time PCR in brain and lung) was studied and compared with that induced by the laboratory strain H37Rv and other five clinical strains isolated from patients with pulmonary TB. All the clinical isolates from meningeal TB patients disseminated extensively through the hematogenous route infecting the brain, producing inflammation in the cerebral parenchyma and meninges, whereas H37Rv and clinical isolates from pulmonary TB patients showed very limited efficiency to infect the brain. Thus, it seems that mycobacterial strains with a distinctive genotype are able to disseminate extensively after the respiratory infection and infect the brain.

[A systematic review on the protective efficacy of BCG against children tuberculosis meningitis and millet tuberculosis]

OBJECTIVE

To Understand the protective efficacy of Bacillus Calmette Guerin (BCG) vacciation against children tuberculosis meningitis and millet tuberculosis, to provide the data to improve immune tactics of BCG.

METHODS

A search CHKD full text database (1979-2007) and CHKD meeting paper database (1999-2008) and WANGFANG database (1982-2007), with BCG, tuberculosis meningitis, millet tuberculosis, then to analyze information from qualified literatures.

RESULTS

28 paper were involved. 25 were correlated with tuberculosis meningitis, 1 correlated with millet tuberculosis, 2 correlated with both. The study about protections of BCG against tuberculosis meningitis showed that BCG has protective action in ecology study. The inoculation of BCG in tuberculosis meningitis cases was 0-69.08%, millet tuberculosis BCG inoculating with 82.76%. Result of Mete analysis showed that it was 81% to the protection tuberculosis meningitis, 95% CI is 57%-91%.

CONCLUSION

BCG vaccine has protective effect for preventing tuberculous meningitis. Due to lack of case-control study, cases in vaccinated and unvaccinated ratio should not an objective description of the effect of BCG vaccination. Protective effect of miliary tuberculosis research literature was less, unable to come to precise conclusions.

rpoB nested PCR and sequencing for the early diagnosis of tuberculous meningitis and rifampicin resistance

SETTING

The prognosis of tuberculous meningitis (TBM) is linked to early diagnosis and prescription of adequate treatment.

OBJECTIVE

To evaluate the efficacy of the rpoB nested polymerase chain reaction (PCR) and sequencing assay to detect and identify Mycobacterium tuberculosis complex (MTC) strains and strains resistant to rifampicin (RMP) in cerebrospinal fluid specimens (CSF) from patients with highly suspected TBM.

DESIGN

Retrospective blinded hospital-based study.

RESULTS

rpoB nested PCR and sequencing assay detected MTC in 31/36 CSF specimens from 16 patients with clinically suspected TBM. All of the control CSF specimens from 25 patients with non-TBM showed negative results. One of the 16 patients had a mutation at codon C526G as compared to the rpoB sequences in GenBank. This corresponds to a diagnostic sensitivity of 86% (95%CI 71-95) and a specificity of 100% (95%CI 86-100).

CONCLUSION

Our results suggest that rpoB nested PCR and sequencing assay can detect MTC and simultaneously determine its RMP susceptibility in CSF from patients with highly suspected TBM.

Aspergillus fumigatus meningitis in immunosuppressed patients; diagnosis, management, prevention and control

Aspergillosis is a fungal disease that may be expressed by a diversity of clinical syndromes being produced by several of more than 170 Aspergillus species. The "Matei Balş" National Institute for Infectious Diseases has a long experience in diagnostic procedures and treatment of the immunosuppressed patients. Irrespective of the place of their residence, most patients with HIV infection and AIDS were investigated in the Institute in the last two decades. The first case of double central nervous infection (Mycobacterium tuberculosis and Aspergillus fumigatus) in a HIV positive patient is discussed.

[A meningitis case of Brucella and tuberculosis co-infection]

Turkey is located at an endemic area for brusellosis and tuberculosis which are both important public health problems. Meningitis caused by Brucella and Mycobacterium spp. may be confused since the clinical and laboratory findings are similar. In this report, a meningitis case with Brucella and tuberculosis co-infection has been presented. A 19-years-old woman was admitted to our clinic with severe headache, fever, vomiting, meningeal irritation symptoms, confusion and diplopia. The patient was initially diagnosed as Brucella meningitis based on her history (stockbreeding, consuming raw milk products, clinical symptoms concordant to brucellosis lasting for 4-5 months), physical examination and laboratory findings of cerebrospinal fluid (CSF). Standard tube agglutination test for brucellosis was positive at 1/80 titer in CSF and at 1/640 titer in serum, whereas no growth of Brucella spp. was detected in CSF and blood cultures. Antibiotic therapy with ceftriaxone, rifampicin and doxycyclin was started, however, there was no clinical improvement and agitation and confusion of the patient continued by the end of second day of treatment. Repeated CSF examination yielded acid-fast bacteria. The patient was then diagnosed as meningitis with double etiology and the therapy was changed to ceftriaxone, streptomycin, morphozinamide, rifampicin and isoniazid for thirty days. Tuberculosis meningitis was confirmed with the growth of Mycobacterium tuberculosis on the 14th day of cultivation (BACTEC, Becton Dickinson, USA) of the CSF sample. On the 30th day of treatment she was discharged on anti-tuberculous treatment with isoniazid and rifampicin for 12 months. The follow-up of the patient on the first and third months of treatment revealed clinical and laboratory improvement. Since this was a rare case of Brucella and tuberculosis co-infection, this report emphasizes that such co-infections should be kept in mind especially in the endemic areas for tuberculosis and brucellosis.

The influence of host and bacterial genotype on the development of disseminated disease with Mycobacterium tuberculosis

The factors that govern the development of tuberculosis disease are incompletely understood. We hypothesized that some strains of Mycobacterium tuberculosis (M. tuberculosis) are more capable of causing disseminated disease than others and may be associated with polymorphisms in host genes responsible for the innate immune response to infection. We compared the host and bacterial genotype in 187 Vietnamese adults with tuberculous meningitis (TBM) and 237 Vietnamese adults with uncomplicated pulmonary tuberculosis. The host genotype of tuberculosis cases was also compared with the genotype of 392 cord blood controls from the same population. Isolates of M. tuberculosis were genotyped by large sequence polymorphisms. The hosts were defined by polymorphisms in genes encoding Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP) and Toll-like receptor-2 (TLR-2). We found a significant protective association between the Euro-American lineage of M. tuberculosis and pulmonary rather than meningeal tuberculosis (Odds ratio (OR) for causing TBM 0.395, 95% confidence intervals (C.I.) 0.193–0.806, P = 0.009), suggesting these strains are less capable of extra-pulmonary dissemination than others in the study population. We also found that individuals with the C allele of TLR-2 T597C allele were more likely to have tuberculosis caused by the East-Asian/Beijing genotype (OR = 1.57 [95% C.I. 1.15–2.15]) than other individuals. The study provides evidence that M. tuberculosis genotype influences clinical disease phenotype and demonstrates, for the first time, a significant interaction between host and bacterial genotypes and the development of tuberculosis.

Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, kills over 2 million people each year. It is estimated that approximately one-third of the world population is infected with M. tuberculosis, though the majority will never develop active disease. The most severe form of tuberculosis occurs when the bacterium spreads to the brain to cause meningitis. We examined whether the genetic variation of the person and the bacteria influenced the type of disease a person develops. We have previously shown that certain mutations in genes of the human immune system can predispose adults in Vietnam to developing tuberculous meningitis. In this study we show that some strains of M. tuberculosis commonly found in Europe and America are less likely to cause tuberculous meningitis in Vietnamese adults than strains predominantly found in Asia. We then looked at the interaction between M. tuberculosis strains and mutations in human immune genes and show that a particular mutation, TLR2 T597C, is more commonly found in patients infected with the East-Asian/Beijing strains of M. tuberculosis. This is the first study to look at both the host and pathogen genotypes together in tuberculosis infection, and the findings suggest that the outcome of exposure to M. tuberculosis can depend on both the human genotype and the bacterial genotype.

Drug susceptibility profiling of tuberculous meningitis

Drug-resistant tuberculosis is an increasing problem worldwide. There are few reports of drug susceptibility patterns of Mycobacterium tuberculosis isolated from cases of tuberculous meningitis. A 5-year retrospective study aimed at analysing the drug susceptibility profile of M. tuberculosis isolated from tuberculous meningitis cases was conducted. A total of 366 isolates were analysed. Among these, 301 (82.2%) were sensitive to all the four primary drugs tested, while 65 (17.8%) showed resistance. There were 46 (12.5%) isolates resistant to isoniazid (INH), while 9 (2.4%) demonstrated multidrug resistance. These data suggest that multidrug resistance in tuberculous meningitis is not yet a serious problem. However, a periodic review is required to ascertain the global incidence of drug-resistant tuberculous meningitis.

[Gamma interferon testing in blood and cerebrospinal fluid--rapid method for the diagnosis of tuberculous meningitis]

AIM

To evaluate the benefit of this early method of diagnosis of tuberculous meningitis, gamma-interferon levels comparatively in blood and cerebrospinal fluid (CSF).

MATERIAL AND METHOD

We have studied 50 patients with tuberculous meningitis admitted in the Clinic of Infectious Diseases Iaşi between 2006-2007, from the epidemiological, clinical, diagnosis and therapeutical points of view.

RESULTS

Tuberculous meningitis was more frequent in males, with a mean ration of 2.5. The age of patients varied between 2 and 78 years of age, with a mean value of 30.5 years. 35.6% of patients were children. In 32 cases the meningeal infection was secondary, disseminated from a primary site, most frequently from the lungs (68,7%). The bacteriologic confirmation was through culture in 13.3%, with an average of 23.4 days of incubation. In whole blood the sensitivity Quantiferon TB Gold assay (QTF) was 78.57%. In CSF the specificity was higher than in blood (96.1 vs. 88.4%), having a positive prediction value over 90%. Antituberculous therapy prior to QTF testing had a negative impact, 50 to 6 cases having negative QTF results.

CONCLUSION

The performance indicators of TB Gold Quantiferon Test in serum or CSF are high, being more sensitive and rapid than the direct exam of CSF or BK culture.