Search

Point-of-care tests for tuberculous meningitis (TBM) are needed. We studied the diagnostic accuracy of the lipoarabinomannan (LAM) lateral flow assay (LFA), LAM enzyme-linked immunosorbent assay (ELISA), and Xpert MTB/RIF in cerebrospinal fluid (CSF) in an autopsy cohort of Ugandan HIV-infected adults. We obtained written informed consent postmortem from the next of kin. A complete autopsy was done and CSF obtained. We performed LAM LFA (on unprepared and supernatant CSF after heating and spinning), LAM ELISA, and Xpert MTB/RIF on the CSF samples. Accuracy parameters were calculated for histopathological TBM and also for the composite standard, including Xpert MTB/RIF-positive cases. We tested CSF of 91 patients. LAM LFA had a sensitivity of 75% for definite histopathological TBM, ELISA a sensitivity of 43%, and Xpert MTB/RIF a sensitivity of 100% and specificities of 87%, 91%, and 87%, respectively. LAM LFA had a sensitivity of 50% for definite and probable histopathological TBM, ELISA a sensitivity of 38%, and Xpert MTB/RIF a sensitivity of 86% and specificities of 70%, 91%, and 87%, respectively. LAM LFA had a sensitivity of 68% for the composite standard and ELISA a sensitivity of 48% and specificities of 78% and 98%, respectively. The rapid diagnostic tests detected TBM in 22% to 78% of patients not on anti-TB treatment. Point-of-care tests have high accuracy in diagnosis of TBM in deceased HIV-infected adults. LAM LFA in CSF is a useful additional diagnostic tool., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Objective: The detection of urinary lipoarabinomannan (LAM), a mycobacterial cell wall component, is used to diagnose tuberculosis (TB). How LAM enters the urine is not known. To investigate if urinary LAM-positivity is the result of renal TB infection we correlated the outcomes of urinary LAM-antigen testing to renal histology in an autopsy cohort of hospitalized, Ugandan, HIV-infected adults., Methods: We performed a complete autopsy, including renal sampling, in HIV-infected adults that died during hospitalization after written informed consent was obtained from the next of kin. Urine was collected postmortem through post-mortem catheterisation or by bladder puncture and tested for LAM with both a lateral flow assay (LFA) and an ELISA assay. Two pathologists assessed the kidney histology. We correlated the LAM-assay results and the histology findings., Results: Of the 13/36 (36%) patients with a positive urinary LAM ELISA and/or LFA, 8/13 (62%) had renal TB. The remaining 5 LAM-positive patients had disseminated TB without renal involvement. Of the 23 LAM-negative patients, 3 had disseminated TB without renal involvement. The remaining LAM-negative patients had no TB infection and died mostly of fungal and bacterial infections. LAM LFA had a sensitivity of 81% and specificity of 100% to diagnose TB at any location, and the LAM ELISA a sensitivity of 63% and a specificity of 100%. 54% (7/13) LAM LFA-positive patients were not on anti-TB treatment at the time of death., Conclusion: Renal TB infection explained LAM-positivity in the majority of patients. Patients with disseminated TB without renal involvement can also be diagnosed with LAM. This suggests that other mechanisms that lead to urinary LAM-positivity exist in a minority of patients.

Introduction: Minimal invasive but accurate methods to establish the cause of death in HIV-infected patients are needed. We studied the agreement in cause of death between blind and ultrasound-guided needle autopsy and complete autopsy in HIV-infected patients in Uganda., Methods: We subsequently performed a blind and ultrasound-guided needle autopsy followed by a complete autopsy in HIV-infected adults who died during hospitalization. Two teams of pathologists reviewed the tissue from either the needle autopsies or the complete autopsy and formulated the major diagnoses, that is, diseases directly contributing to death. The primary outcome was concordance in major diagnosis between needle and complete autopsies., Results: We performed 96 blind needle and complete autopsies and 95 ultrasound-guided needle autopsies. Concordance in major diagnosis between blind needle and complete autopsy was 50%. For the main major diagnosis, tuberculosis (TB) concordance was higher (71%; P < 0.01). Blind needle autopsy identified at least 1 major diagnosis in 60% of patients; and in 46%, there was complete concordance for all major diagnoses. The main reason for discordance was sampling error of the lesion. Concordance with the addition of ultrasound guidance was 52% for all major diagnoses and 79% for TB. Major diagnoses were mainly identified in tissue cores from the liver (76%) and the spleen (82%)., Discussion: Blind needle autopsy identified half of the major diagnosis. The addition of ultrasound guidance did not significantly improve the performance of needle autopsy. Needle autopsy is a valuable method to confirm causes of death in HIV-infected patients, especially for highly prevalent diseases like TB.

Background: Information on causes of death in HIV-infected patients in Sub-Saharan Africa is mainly derived from observational cohort and verbal autopsy studies. Autopsy is the gold standard to ascertain cause of death. We conducted an autopsy study to describe and compare the clinical and autopsy causes of death and contributory findings in hospitalized HIV-infected and HIV-uninfected patients in Uganda., Methods: Between May and September 2009 a complete autopsy was performed on patients that died on a combined infectious diseases gastroenterology ward in Mulago Hospital in Kampala, Uganda. Autopsy cause of death and contributing findings were based on the macro- and microscopic post-mortem findings combined with clinical information. Clinical diagnoses were reported by the ward doctor and classified as confirmed, highly suspected, considered or not considered, based on information derived from the medical chart. Results are reported according to HIV serostatus., Results: Fifty-three complete autopsies were performed in 66% HIV-positive, 21% HIV-negative and 13% patients with an unknown HIV serological status. Infectious diseases caused death in 83% of HIV-positive patients, with disseminated TB as the main diagnosis causing 37% of deaths. The spectrum of illness and causes of death were substantially different between HIV-positive and HIV-negative patients. In HIV-positive patients 12% of postmortem diagnoses were clinically confirmed, 27% highly suspected, 16% considered and 45% not considered. In HIV-negative patients 17% of postmortem diagnoses were clinically highly suspected, 42% considered and 42% not considered., Conclusion: Autopsy examination remains an important tool to ascertain causes of death particularly in settings with limited access to diagnostic testing during life. HIV-positive patients continue to die from treatable and clinically undiagnosed infectious diseases. Until rapid-point of care testing is available to confirm common infections, empiric treatment should be further investigated.

The point mutations in the Plasmodium falciparum dihydrofolate reductase (dhfr) and the dihydropteroate synthase (dhps) genes that are linked to sulphadoxine-pyrimethamine (SP) resistance in vitro have been well characterised. To determine whether a few of these mutations could predict SP treatment failure in vivo, two mutations (Asn-108 and Arg-59) in the dhfr gene and one (Glu-540) in the dhps gene were analysed according to the risk of SP parasitological failure (RI-RIII) at day 28 in pre-treatment isolates in 79 Ugandan children aged 6-59 (mean = 18.4, S.D. = 8.8) months with uncomplicated falciparum malaria. Neither the dhfr-108 (P = 0.3) nor the dhps-540 (P = 0.6) or dhfr-108 + dhps-540 (P = 0.04) mutations were significantly associated with SP parasitological failure. However, the dhfr-108 + dhfr-59 (P = 0.04), the dhfr-59 + dhps-540 (P = 0.04) and the dhfr-108 + dhfr-59 + dhps-540 (P = 0.02) mutations significantly increased the risk for SP parasitological failure. Our findings confirm an earlier report that the dhfr-59 and the dhps-540 mutations could be useful genetic markers for rapid screening of populations at high risk of SP resistance.

The rapid development of falciparum resistance to sulphadoxine-pyrimethamine (SP) in East and Central Africa has raised concerns as to the efficacy of combining it with another drug. In 2002, we assessed the efficacy of SP alone and combined with amodiaquine (AQ/SP) or chloroquine (CQ/SP) in Ugandan children with uncomplicated falciparum malaria. At day 14, adequate clinical response was 100% (84/84) for AQ/SP, 93% (92/101) for CQ/SP and 91% (73/80) for SP. At day 28, parasitological failure (RI-RIII) occurred in 16% (13/80) of children treated with AQ/SP, in 48% (48/100) of those treated with CQ/SP and in 61% (48/79) of those treated with SP alone. Compared with the AQ/SP arm, the odds for parasitological failure at day 28 were five times higher (95% CI, 2-10) in the CQ/SP group and sevenfold higher (95% CI, 3-17) in that of SP alone. CQ/SP does not offer any significant added benefit over SP alone while AQ/SP is an efficacious low-cost combination. These findings have important policy implications for Uganda and other resource-constrained African countries faced with the problematic choice of a new first-line antimalarial treatment in a context of high CQ resistance.

Mutations in the dihydrofolate reductase gene (dhfr) of Plasmodium falciparum have been proposed as molecular markers for the surveillance of sulfadoxine-pyrimethamine (SP)-resistant malaria, but such proposals have not been validated. At 7 Ugandan sites in 1999, we determined the population-based prevalence of infections with mutations and the mutant allele frequency of dhfr codons 108, 51, and 59 using a random sample of infected individuals aged 1-45 years. Sulfadoxine-pyrimethamine treatment failure was independently estimated by in vivo tests in 327 children aged 6-59 months with clinical malaria. The prevalence of infections with the single point mutations and the dhfr codons 108 and 51 mutant allele frequency were not correlated to SP treatment failure. However, the dhfr codon 59 mutant allele frequency was positively correlated to SP treatment failure (r = 0.72, P = 0.06). The ratio of the infections with the mutant to wild genotype (M/W) and that of the mutant to wild allele (MA/WA) had the same values. Both dhfr codon 59 M/W and MA/WA ratio were significantly and positively correlated to SP treatment failure (r = 0.73, P = 0.05). Moreover, the prevalence of infections with only 2 mutations (Asn-108 plus Ile-51) was significantly and inversely correlated to the prevalence of infections with 3 mutations (Asn-108 plus Ile-51 plus Arg-59) (r = 0.92, P = 0.004), suggesting the stepwise accumulation of the dhfr mutations is Asn-108 Ile-51 Arg-59 and further supporting the idea of using the dhfr codon 59 M/W ratio as a molecular index for the prediction of SP treatment failure. Atthe population level, the dhfr codon 59 M/W ratio is a simple and stable index for the estimation of SP treatment failure.

The mutant genotype at codon 76 of the pfcrt gene (T76) has been proposed as a molecular marker for surveillance of chloroquine (CQ)-resistant Plasmodium falciparum malaria but this proposal has not been validated by population-based surveys. In 1998-99, in 6 Ugandan sentinel sites, the prevalence of P. falciparum infections with the T76 genotype and the level of CQ use were measured by community surveys, and CQ resistance was determined by in-vivo tests on 6-59-month-old children with clinical malaria. The prevalence of T76 was not related to the overall clinical (early and late treatment failure: ETF + LTF; r = 0.14, P = 0.78) or parasitological (RI + RII + RIII; r = 0.17, P = 0.73) CQ resistance. However, the percentage of individuals carrying only infections with the T76 genotype (T76 alone) increased with increasing ETF (r = 0.76, P = 0.07) and type RIII parasitological failure (r = 0.69, P = 0.12). Similarly, the ratio between T76 and K76 (the wild type) prevalences (T76/K76) was strongly and positively correlated with ETF (r = 0.85, P = 0.03) and RIII (r = 0.82, P = 0.04). Moreover, T76 alone (r = 0.90, P = 0.01) as well as T76/K76 (r = 0.90, P = 0.01) significantly increased with increasing community CQ use. T76 alone and T76/K76 can be useful markers to estimate the ETF and RIII prevalence as well as the amount of CQ use in the community.

We studied (in 1998 and 1999) some factors that may be linked to the spread of chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) resistance in 7 discrete communities in Uganda. Exposure to malaria infection was measured by parasitological surveys in children aged 1-9 years, drug use by community surveys and drug resistance by in-vivo tests on children aged 6-59 months with clinical malaria. CQ use was inversely related to parasite prevalence (r = -0.85, P = 0.01). CQ and SP treatment failure rates varied significantly according to parasite prevalence (P = 0.001 and 0.04 respectively). The highest CQ (42.4%, 43.8%) and SP (12.5%, 14.8%) treatment failure rates were observed in sites characterized by high parasite prevalence. Using areas with medium parasite prevalence as reference, the relative risk (RR) for CQ treatment failure was 3.2 (95% CI 1.6-6.4) in high parasite prevalence sites and 3.1 (95% CI 1.2-7.7) in low parasite prevalence sites. The RR for SP treatment failure was also higher in sites with high parasite prevalence but low in those with low parasite prevalence. According to our findings, drug resistance seems to spread faster in higher transmission areas, regardless of drug pressure. In low transmission areas, drug pressure seems to be the critical factor. A decrease in transmission coupled with rational use of drugs may delay the spread of resistance.