Characterization of genotypes of Enterocytozoon bieneusi in immunosuppressed and immunocompetent patient groups.

A retrospective phylogenetic analysis was performed on isolates of Enterocytozoon bieneusi to characterize the genotypes in different patient cohorts. Fifty-seven isolates, collected from patients living in Malawi and the Netherlands, were classified by age and immune status of the hosts. Sequence analysis of the internal transcribed spacer (ITS) region identified 16 genotypes; nine have not previously been described. Genotypes K and D were most prevalent among patient groups, whereas genotype C was restricted to transplantation patients receiving immunosupressives and genotype B showed a predisposition toward patients living with HIV/AIDS. Different genotypes showed more dispersion among isolates from Malawi compared with those from the Netherlands. A constructed map estimating the genealogy of the ITS region reveals a dynamic evolutionary process between the genotypes.

Real-time polymerase chain reaction for detection of Isospora belli in stool samples.

A real-time polymerase chain reaction (PCR) assay targeting the internal transcribed spacer 2 region of the ribosomal RNA gene was developed for the detection of Isospora belli DNA in fecal samples, including an internal control to detect inhibition during the amplification process. The assay was performed on species-specific DNA controls (n = 27) and a range of positive (n = 21) and negative (n = 120) stool samples, and achieved 100% specificity and sensitivity. The simple fecal sample collection procedure, the high-throughput potential, and the possibility of quantification makes the I. belli real-time PCR assay a powerful diagnostic tool for epidemiologic studies with possibilities for extension to other helminthes and protozoa using additional molecular targets. In addition, this Isospora PCR could augment the clinical laboratory diagnosis of isosporiasis, in particular, in patients with a travel history to developing countries.

Pneumocystis pneumonia in HIV-positive adults, Malawi.

In a prospective study of 660 HIV-positive Malawian adults, we diagnosed Pneumocystis jirovecii pneumonia (PcP) using clinical features, induced sputum for immunofluorescent staining, real-time PCR, and posttreatment follow-up. PcP incidence was highest in patients with the lowest CD4 counts, but PcP is uncommon compared with incidences of pulmonary tuberculosis and bacterial pneumonia.

Observational cohort study of HIV-infected African children.

BACKGROUND: Most information about children living with HIV is based on follow up from children identified through mother-to-child transmission studies. Children identified through voluntary counseling and testing (VCT) represent a unique cohort that has not been previously described in the literature. METHODS: Children who were found to have HIV infection through VCT were offered enrollment in this study. They were evaluated monthly and encouraged to return to the clinic any time they were ill. Thorough evaluation was performed for every illness. RESULTS: Forty-five children were enrolled in the study. Many of the participants (33%) had a serious acute disease at the time of enrollment. The most common diagnoses were symptomatic malaria and pneumonia. The children were more ill than adults who were enrolled in a simultaneous study and had a higher death rate (37 versus 15 deaths per 100 person-years of observation). The mortality rate was 22%. Undernutrition and low CD4 cell count were independently associated with increased risk of death. CONCLUSIONS: Malawian children found to be HIV-infected through VCT had a high morbidity and mortality rate, highlighting the potential benefit of trimethoprim-sulfamethizole prophylaxis and available antiretroviral therapy.

A community-based study of the incidence of trimethoprim-sulfamethoxazole-preventable infections in Malawian adults living with HIV.

The benefits of trimethoprim-sulfamethoxazole (TS) prophylaxis reported for persons living with HIV in Cote d'Ivoire are difficult to extrapolate to sub-Saharan African countries where bacterial resistance to TS is higher and cross-resistance between TS and sulfadoxine-pyrimethamine (SP) may impair SP efficacy for malaria treatment. We conducted a community-based cohort study to measure the incidence of potentially TS-preventable illnesses in Blantyre, Malawi. We found a high incidence of malaria, invasive bacterial infections, and probable bacterial pneumonias but low rates of Pneumocystis jiroveci pneumonia, isosporiasis, and Toxoplasma encephalitis. Most bacterial isolates were resistant to TS but sensitive to azithromycin, a possible alternative to TS. Clinical trials are needed to determine the role of TS or alternative regimens for prophylaxis against secondary infections among people living with HIV in sub-Saharan Africa. These should also assess benefit in patients receiving antiretroviral therapy.