Evaluation of the Performance of the Loopamp Trypanosoma cruzi Detection Kit for the Diagnosis of Chagas Disease in an Area Where It Is Not Endemic, Spain.

In Spain, PCR is the tool of choice for the diagnosis of congenital Chagas disease (CD) and serology for diagnosing chronic CD. A loop-mediated isothermal amplification test for Trypanosoma cruzi DNA detection showed good analytical performance and ease of use. We aimed to evaluate the performance of the Loopamp Trypanosoma cruzi detection kit (Eiken Chemical Co. Ltd., Japan) (Tcruzi-LAMP) for congenital and chronic CD diagnosis using well-characterized samples. We included samples from 39 congenital and 174 chronic CD cases and from 48 uninfected children born to infected mothers and 34 nonchagasic individuals. The sensitivity, specificity, and accuracy of Tcruzi-LAMP were estimated using standard case definitions for congenital CD (positive result by parasitological or PCR tests or serology after 9 months of age) and chronic CD (positive serology by at least two tests). The Tcruzi-LAMP results were read by visual examination and a real-time fluorimeter. For congenital CD, Tcruzi-LAMP sensitivity was 97% for both types of reading; specificity was 92% by visual examination and 94% by fluorimeter. For chronic CD, sensitivity was 47% and specificity 100%. The accuracy in congenital CD was >94% versus 56% in chronic CD. The agreement of Tcruzi-LAMP with PCR tests was better in congenital CD (kappa, 0.86 to 0.91) than in chronic CD (kappa, 0.67 to 0.83). The Loopamp Trypanosoma cruzi detection kit showed good performance for the diagnosis of congenital CD. Tcruzi-LAMP, like PCR, can be useful for the screening and early diagnosis of congenital infection.

Molecular characterization of rpoB gene mutations in isolates from tuberculosis patients in Cubal, Republic of Angola.

BACKGROUND: The importance of Mycobacterium tuberculosis strains with disputed rpoB mutations remains to be defined. This study aimed to assess the frequency and types of rpoB mutations in M. tuberculosis isolates from Cubal, Angola, a country with a high incidence of tuberculosis. METHODS: All isolates included (n = 308) were analyzed using phenotypic drug susceptibility testing and GenoType MTBDRplus assay. DNA sequencing of the rpoB gene and determination of rifampicin MIC by macrodilution method were additionally performed on isolates yielding discordant results (n = 12) and those in which the mutation detected was not characterized (n = 8). RESULTS: In total, 85.1% (74/87) of rifampicin-resistant strains had undisputed rpoB mutations -S450L (49), D435V (15), H445D (3), H445Y (2), Q432ins (1), L449M plus S450F (1), S450F (1), S450W (1) and S450Y (1)-; 10.3% (9/87) had disputed rpoB mutations-L430P plus S493L (1), N437del (1), H445L (3), D435Y (2), L452P (2)-, 2.3% (2.3%) showed no rpoB mutations and 2.3% (2/87) showed heteroresistance-D435Y plus L452P and L430P plus S493L-. CONCLUSION: Disputed rpoB mutations were common, occurring in 10.3% of rifampicin resistant isolates. Current phenotyping techniques may be unable to detect this resistance pattern. To increase their sensitivity, a lower concentration of RIF could be used in these tests or alternatively, rpoB mutations could be screened and characterized in all M. tuberculosis strains.

Three-year multicenter surveillance of community-acquired Listeria monocytogenes meningitis in adults.

BACKGROUND: Listeria monocytogenes is the third most frequent cause of bacterial meningitis. The aim of this study is to know the incidence and risk factors associated with development of acute community-acquired Lm meningitis in adult patients and to evaluate the clinical features, management, and outcome in this prospective case series. METHODS: A descriptive, prospective, and multicentric study carried out in 9 hospitals in the Spanish Network for Research in Infectious Diseases (REIPI) over a 39-month period. All adults patients admitted to the participating hospitals with the diagnosis of acute community-acquired bacterial meningitis (Ac-ABM) were included in this study. All these cases were diagnosed on the basis of a compatible clinical picture and a positive cerebrospinal fluid (CSF) culture or blood culture. The patients were followed up until death or discharge from hospital. RESULTS: Two hundred and seventy-eight patients with Ac-ABM were included. Forty-six episodes of Lm meningitis were identified in 46 adult patients. In the multivariate analysis only age (OR 1.026; 95% CI 1.00-1.05; p = 0.042), immunosuppression (OR 2.520; 95% CI 1.05-6.00; p = 0.037), and CSF/blood glucose ratio (OR 39.42; 95% CI 4.01-387.50; p = 0.002) were independently associated with a Lm meningitis. The classic triad of fever, neck stiffness and altered mental status was present in 21 (49%) patients, 32% had focal neurological findings at presentation, 12% presented cerebellum dysfunction, and 9% had seizures. Twenty-nine (68%) patients were immunocompromised. Empirical antimicrobial therapy was intravenous ampicillin for 34 (79%) of 43 patients, in 11 (32%) of them associated to aminoglycosides. Definitive ampicillin plus gentamicin therapy was significantly associated with unfavourable outcome (67% vs 28%; p = 0.024) and a higher mortality (67% vs 32%; p = 0.040).The mortality rate was 28% (12 of 43 patients) and 5 of 31 (16.1%) surviving patients developed adverse clinical outcome. CONCLUSIONS: Elderly or immunocompromised patients, and a higher CSF/blood glucose ratio in patients with Ac-ABM must alert clinicians about Lm aetiology. Furthermore, we observed a high incidence of acute community-acquired Lm meningitis in adults and the addition of aminoglycosides to treatment should be avoid in order to improve the patients' outcome. Nevertheless, despite developments in intensive care and antimicrobial therapy, this entity is still a serious disease that carries high morbidity and mortality rates.