Bacterial infections in Lilongwe, Malawi: aetiology and antibiotic resistance.

BACKGROUND: Life-threatening infections present major challenges for health systems in Malawi and the developing world because routine microbiologic culture and sensitivity testing are not performed due to lack of capacity. Use of empirical antimicrobial therapy without regular microbiologic surveillance is unable to provide adequate treatment in the face of emerging antimicrobial resistance. This study was conducted to determine antimicrobial susceptibility patterns in order to inform treatment choices and generate hospital-wide baseline data. METHODS: Culture and susceptibility testing was performed on various specimens from patients presenting with possible infectious diseases at Kamuzu Central Hospital, Lilongwe, Malawi. RESULTS: Between July 2006 and December 2007 3104 specimens from 2458 patients were evaluated, with 60.1% from the adult medical service. Common presentations were sepsis, meningitis, pneumonia and abscess. An etiologic agent was detected in 13% of patients. The most common organisms detected from blood cultures were Staphylococcus aureus, Escherichia coli, Salmonella species and Streptococcus pneumoniae, whereas Streptococcus pneumoniae and Cryptococcus neoformans were most frequently detected from cerebrospinal fluid. Haemophilus influenzae was rarely isolated. Resistance to commonly used antibiotics was observed in up to 80% of the isolates while antibiotics that were not commonly in use maintained susceptibility. CONCLUSIONS: There is widespread resistance to almost all of the antibiotics that are empirically used in Malawi. Antibiotics that have not been widely introduced in Malawi show better laboratory performance. Choices for empirical therapy in Malawi should be revised accordingly. A microbiologic surveillance system should be established and prudent use of antimicrobials promoted to improve patient care.

Prevention of mother-to-child transmission: program changes and the effect on uptake of the HIVNET 012 regimen in Malawi.

OBJECTIVE(S): To evaluate uptake of HIV testing in a prevention of mother-to-child transmission program (PMTCT) in Lilongwe, Malawi from April 2002 until December 2006. DESIGN: Retrospective analysis of monthly reports from the beginning of the program. SETTING: Four antenatal clinics in Lilongwe, Malawi. METHODS: Pregnant women attending urban antenatal clinics in Lilongwe were invited to participate in a PMTCT program. Women were given information and education on antenatal care and PMTCT in groups of 8 to 12. Written informed consent for HIV testing was obtained privately. Women returned for the test result 1-2 weeks later. Mothers and infants were given the HIVNET 012 regimen. Rapid HIV testing and 'opt-out' testing were instituted in July 2003 and April 2005, respectively. Infants were tested using HIV DNA PCR and, if HIV positive, a CD4 cell percentage was obtained and the infants were referred for further medical evaluation and treatment. RESULTS: The program reached 20 000 pregnant women in the first 12 months. Acceptance of HIV testing increased from 45% to 73% (P < 0.001) when rapid, same day testing was instituted. When opt-out testing was instituted, 99% of the mothers agreed to testing. Of the infants tested, 15.5% were HIV positive. CONCLUSION: Rapid HIV testing using the opt-out method increased acceptance of HIV testing in the PMTCT program to 99% in urban Lilongwe, Malawi.

Amplified transmission of HIV-1: comparison of HIV-1 concentrations in semen and blood during acute and chronic infection.

OBJECTIVES: This study was conducted to compare viral dynamics in blood and semen between subjects with antibody negative, acute HIV-1 infection and other subjects with later stages of infection. DESIGN: A prospective cohort study was embedded within a cross-sectional study of HIV screening in a Lilongwe, Malawi STD clinic. METHODS: Blood samples from HIV antibody negative or indeterminate volunteers were used to detect HIV RNA in plasma using a pooling strategy. Blood and seminal plasma HIV-1 RNA concentrations were measured over 16 weeks. RESULTS: Sixteen men with acute HIV infection and 25 men with chronic HIV infection were studied. Blood viral load in subjects with acute HIV infection was highest about 17 days after infection (mean +/- SE, 6.9 +/- 0.5 log10 copies/ml), while semen viral load peaked about 30 days after infection (4.5 +/- 0.4 log10 copies/ml). Semen viral load declined by 1.7 log10 to a nadir by week 10 of HIV infection. Semen and blood viral loads were more stable in chronically infected subjects over 16 weeks. Higher semen levels of HIV RNA were noted in subjects with low CD4 cell counts. CONCLUSIONS: These results provide a biological explanation for reported increases in HIV transmission during the very early (acute) and late stages of infection. Recognizing temporal differences in HIV shedding in the genital tract is important in the development of effective HIV prevention strategies.

HIV and parasitic infection and the effect of treatment among adult outpatients in Malawi.

We measured enteric parasitic infection prevalence and the effect of treatment on human immunodeficiency virus (HIV) RNA levels to assess their importance to HIV primary care in resource-limited settings. Adults in Lilongwe, Malawi, were evaluated, treated, and followed-up for parasitic and HIV infections. Of 389 patients, 266 (68%) were HIV infected. Helminth infections were more common in HIV-uninfected than in HIV-infected patients (39% vs. 17%). Among HIV-infected patients, helminth infections were associated with higher CD4 cell counts but not with higher HIV RNA levels. Successful treatment of parasitic infections had no effect on HIV RNA levels. Although common, parasitic infections did not impact HIV RNA levels.

Low absolute neutrophil counts in African infants.

Infants of African origin have a lower normal range of absolute neutrophil counts than white infants; this fact, however, remains under appreciated by clinical researchers in the United States. During the initial stages of a clinical trial in Malawi, the authors noted an unexpectedly high number of infants with absolute neutrophil counts that would be classifiable as neutropenic using the National Institutes of Health's Division of AIDS toxicity tables. The authors argue that the relevant Division of AIDS table does not take into account the available evidence of low absolute neutrophil counts in African infants and that a systematic collection of data from many African settings might help establish the absolute neutrophil count cutpoints to be used for defining neutropenia in African populations.

A prospective study of bloodstream infections as cause of fever in Malawi: clinical predictors and implications for management.

OBJECTIVE: To determine the contribution of a blood culture service to the diagnosis of fever in a resource-poor setting and to identify clinical predictors of specific bloodstream infections (BSI). METHODS: In a descriptive, prospective study at the Medical Wards at Queen Elizabeth Central Hospital, Blantyre, Malawi, we tried to identify a specific cause of fever in febrile patients, comparing the use of routinely available diagnostic methods with the same methods plus blood culture. Clinical predictors of specific BSIs were sought. RESULTS: A total of 352 patients admitted with fever (axillary temperature > or =37.4 degrees C) or a history of fever within the last 4 days were enrolled. Tuberculosis (TB) was the diagnosis most commonly suspected initially on clinical grounds (28%), followed by lower respiratory tract infection (16%), malaria (12%) and gastroenteritis (5%). Blood cultures were positive in 128 patients (36%); Mycobacterium tuberculosis was the most commonly isolated organism (57 patients). In most cases the diagnosis of TB had already been made using routinely available diagnostic methods, including chest radiography. In all 16 cases of Streptococcus pneumoniae bacteraemia, infection with this agent was clinically suspected, usually on the basis of pulmonary symptoms and signs. In contrast, in 30 of 65 patients (65%) with non-typhi salmonellae (NTS) bacteraemia, there were no symptoms or signs specifically suggestive of this diagnosis. Fever > or =39 degrees C and splenomegaly predicted NTS bacteraemia with an odds ratio of 8.4 (95% confidence interval 3.4-20.6, P < 0.001). CONCLUSION: BSIs are common among patients admitted with fever. While BSI with mycobacteraemia and S. pneumoniae can usually be predicted on clinical grounds and with routinely available diagnostic methods, NTS bacteraemia often presents as a primary BSI without localizing symptoms and signs. Splenomegaly in this population indicates NTS bacteraemia rather than malaria.