Cerebrospinal fluid concentrations of antituberculosis agents in adults and children

Impact of drug resistance on clinical outcome in children with tuberculous meningitis

BACKGROUND

Tuberculous meningitis (TBM) is associated with delayed diagnosis and poor outcome in children. This study investigated the impact of drug resistance on clinical outcome in children with TBM.

METHODS

All children (0-13 years) were included if admitted to Tygerberg Children's Hospital, Cape Town, South Africa, from January 2003 to April 2009 with a diagnosis of either confirmed TBM, or probable TBM with mycobacterial isolation from a site other than cerebrospinal fluid. Mycobacterial samples underwent drug susceptibility testing to rifampin and isoniazid. Children were treated with isoniazid, rifampin, pyrazinamide and ethionamide according to local guidelines.

RESULTS

One hundred twenty-three children were included; 13% (16 of 123) had any form of drug resistance, and 4% (5 of 123) had multidrug-resistant tuberculosis. Time from start of symptoms to appropriate treatment was longer in children with any drug resistance (median: 31 days versus 9 days; P=0.001). In multivariable analysis, young age (P=0.013) and multidrug-resistant tuberculosis (adjusted odds ratio: 12.4 [95% confidence interval: 1.17-132.3]; P=0.037) remained risk factors for unfavorable outcome, and multidrug-resistant tuberculosis remained a risk for death (adjusted odds ratio: 63.9 [95% confidence interval: 4.84-843.2]; P=0.002). We did not detect any difference in outcome between those with isolates resistant to only isoniazid and those with fully susceptible strains (adjusted odds ratio: 0.22 [confidence interval: 0.03-1.87]; P=0.17).

CONCLUSION

Multidrug-resistant TBM in children has poor clinical outcome and is associated with death. We did not find any difference in the outcomes between children with isoniazid monoresistant TBM and those with drug-susceptible TBM. One explanation could be the local treatment regimen. Further investigation of this regimen is indicated.

Influence of antituberculosis drug resistance and Mycobacterium tuberculosis lineage on outcome in HIV-associated tuberculous meningitis

HIV-associated tuberculous meningitis (TBM) has high mortality. Aside from the devastating impact of multidrug resistance (MDR) on survival, little is understood about the influence of other bacterial factors on outcome. This study examined the influence of Mycobacterium tuberculosis drug resistance, bacterial lineage, and host vaccination status on outcome in patients with HIV-associated TBM. Mycobacterium tuberculosis isolates from the cerebrospinal fluid of 186 patients enrolled in two studies of HIV-associated TBM in Ho Chi Minh City, Vietnam, were tested for resistance to first-line antituberculosis drugs. Lineage genotyping was available for 122 patients. The influence of antituberculosis drug resistance and M. tuberculosis lineage on 9-month mortality was analyzed using Kaplan-Meier survival analysis and Cox multiple regression models. Isoniazid (INH) resistance without rifampin resistance was associated with increased mortality (adjusted hazard ratio [HR], 1.78, 95% confidence interval [CI], 1.18 to 2.66; P = 0.005), and multidrug resistance was uniformly fatal (n = 8/8; adjusted HR, 5.21, 95% CI, 2.38 to 11.42; P < 0.0001). The hazard ratio for INH-resistant cases was greatest during the continuation phase of treatment (after 3 months; HR, 5.05 [95% CI, 2.23 to 11.44]; P = 0.0001). Among drug-susceptible cases, patients infected with the "modern" Beijing lineage strains had lower mortality than patients infected with the "ancient" Indo-Oceanic lineage (HR, 0.29 [95% CI, 0.14 to 0.61]; P = 0.001). Isoniazid resistance, multidrug resistance, and M. tuberculosis lineage are important determinants of mortality in patients with HIV-associated TBM. Interventions which target these factors may help reduce the unacceptably high mortality in patients with TBM.

Tuberculous meningitis: diagnosis and treatment overview

Tuberculous meningitis (TBM) is the most common form of central nervous system tuberculosis (TB) and has very high morbidity and mortality. TBM is typically a subacute disease with symptoms that may persist for weeks before diagnosis. Characteristic cerebrospinal fluid (CSF) findings of TBM include a lymphocytic-predominant pleiocytosis, elevated protein, and low glucose. CSF acid-fast smear and culture have relatively low sensitivity but yield is increased with multiple, large volume samples. Nucleic acid amplification of the CSF by PCR is highly specific but suboptimal sensitivity precludes ruling out TBM with a negative test. Treatment for TBM should be initiated as soon as clinical suspicion is supported by initial CSF studies. Empiric treatment should include at least four first-line drugs, preferably isoniazid, rifampin, pyrazinamide, and streptomycin or ethambutol; the role of fluoroquinolones remains to be determined. Adjunctive treatment with corticosteroids has been shown to improve mortality with TBM. In HIV-positive individuals with TBM, important treatment considerations include drug interactions, development of immune reconstitution inflammatory syndrome, unclear benefit of adjunctive corticosteroids, and higher rates of drug-resistant TB. Testing the efficacy of second-line and new anti-TB drugs in animal models of experimental TBM is needed to help determine the optimal regimen for drug-resistant TB.

[Synthesis and antituberculosis activity of the derivatives of glycoside steviolbioside from the plant Stevia rebaudiana and diterpenoid isosteviol containing hydrazone, hydrazide and pyridinoyl moieties]

Conjugates of antitubercular drug Isoniazid (hydrazide of isonicotinic acid), nicotinic and alpha-picolinic acid hydrazides and glycoside steviolbioside from the plant Stevia rebaudiana as well as the product of its acid hydrolysis, diterpenoid isosteviol, were synthesized. Besides, isosteviol hydrazide and hydrazone derivatives as well as conjugates containing two isosteviol moieties connected by dihydrazide linker were also obtained. Both initial compounds and their synthetic derivatives inhibit the growth of Mycobacterium tuberculosis (H37Rv in vitro). The minimum concentration at which the growth of M. tuberculosis was inhibited by 100% (MIC) for stevioside and steviolbioside equals 7.5 and 3.8 microg/mL, respectively. MIC values for conjugates of the hydrazides of pyridine carbonic acids and steviolbioside as well as isosteviol are in the ranges 5-10 and 10-20 microg/mL, respectively. Maximum inhibitory effect against M. tuberculosis showed the conjugates of isosteviol and adipic acid dihydrazide (MIC values ranged from 1.7 to 3.1 microg/mL). Antitubercular activity of the compounds studied is higher than the activity of antitubercular drug Pyrizanamide (MIC = 12.5-20 microg/mL) but lower than the activity of antitubercular drug Isoniazid (MIC = 0.02-0.04 microg/mL).

Aetiology, clinical presentation, and outcome of meningitis in patients coinfected with human immunodeficiency virus and tuberculosis

We conducted a retrospective review of confirmed HIV-TB coinfected patients previously enrolled as part of the SAPiT study in Durban, South Africa. Patients with suspected meningitis were included in this case series. From 642 individuals, 14 episodes of meningitis in 10 patients were identified. For 8 patients, this episode of meningitis was the AIDS defining illness, with cryptococcus (9/14 episodes) and tuberculosis (3/14 episodes) as the commonest aetiological agents. The combination of headache and neck stiffness (78.6%) was the most frequent clinical presentation. Relapsing cryptococcal meningitis occurred in 3/7 patients. Mortality was 70% (7/10), with 4 deaths directly due to meningitis. In an HIV TB endemic region we identified cryptococcus followed by tuberculosis as the leading causes of meningitis. We highlight the occurrence of tuberculous meningitis in patients already receiving antituberculous therapy. The development of meningitis heralded poor outcomes, high mortality, and relapsing meningitis despite ART.