Eduard E. Zijlstra

Epidemics of Invasive Salmonella enterica Serovar Enteritidis and S. enterica Serovar Typhimurium Infection Associated with Multidrug Resistance among Adults and Children in Malawi

BACKGROUND Nontyphoidal salmonellae (NTS) have become the most common cause of bacteremia in tropical Africa, particularly among susceptible children and HIV-infected adults. METHODS We describe 4956 episodes of NTS bacteremia (2439 episodes in adults and 2517 episodes in children) that occurred in Blantyre, Malawi, during the 7-year period 1998-2004. RESULTS A total of 75% of the cases of NTS bacteremia were due to Salmonella enterica serovar Typhimurium, and 21% were due to S. enterica serovar Enteritidis. Epidemic increases in the incidence of NTS bacteremia were seen sequentially, occurring first among cases caused by S. Enteritidis and then among cases caused by S. Typhimurium. Increased incidence of bacteremia was temporally associated with the acquisition of multidrug resistance to ampicillin, cotrimoxazole, and chloramphenicol by each serovar and occurred while the incidence of infection due to other common bloodstream pathogens remained constant. These epidemics were observed among adults and children. A seasonal pattern was also seen, with increased incidence during and after the rainy season. The median age of the patients was 32 years among adults and 22 months among children. Acquisition of multidrug-resistant infection was not associated with an increased case-fatality rate among children (22%), and the case-fatality rate among adults showed a significant trend toward decreasing (from 29% to 20%). CONCLUSIONS These data have important implications for the treatment of severe febrile illness in adults and children in tropical Africa. Further understanding of the molecular basis of these epidemics of multidrug-resistant NTS infection, including ongoing whole-genome sequencing of multidrug-resistant isolates, will yield important tools for the study of NTS pathogenesis, transmission, epidemiology, and prevention.

A Trial of a 7-Valent Pneumococcal Conjugate Vaccine in HIV-Infected Adults.

BACKGROUND Streptococcus pneumoniae is a leading and serious coinfection in adults with human immunodeficiency virus (HIV) infection, particularly in Africa. Prevention of this disease by vaccination with the current 23-valent polysaccharide vaccine is suboptimal. Protein conjugate vaccines offer a further option for protection, but data on their clinical efficacy in adults are needed. METHODS In this double-blind, randomized, placebo-controlled clinical efficacy trial, we studied the efficacy of a 7-valent conjugate pneumococcal vaccine in predominantly HIV-infected Malawian adolescents and adults who had recovered from documented invasive pneumococcal disease. Two doses of vaccine were given 4 weeks apart. The primary end point was a further episode of pneumococcal infection caused by vaccine serotypes or serotype 6A. RESULTS From February 2003 through October 2007, we followed 496 patients (of whom 44% were male and 88% were HIV-seropositive) for 798 person-years of observation. There were 67 episodes of pneumococcal disease in 52 patients, all in the HIV-infected subgroup. In 24 patients, there were 19 episodes that were caused by vaccine serotypes and 5 episodes that were caused by the 6A serotype. Of these episodes, 5 occurred in the vaccine group and 19 in the placebo group, for a vaccine efficacy of 74% (95% confidence interval [CI], 30 to 90). There were 73 deaths from any cause in the vaccine group and 63 in the placebo group (hazard ratio in the vaccine group, 1.18; 95% CI, 0.84 to 1.66). The number of serious adverse events within 14 days after vaccination was significantly lower in the vaccine group than in the placebo group (3 vs. 17, P=0.002), and the number of minor adverse events was significantly higher in the vaccine group (41 vs. 13, P=0.003). CONCLUSIONS The 7-valent pneumococcal conjugate vaccine protected HIV-infected adults from recurrent pneumococcal infection caused by vaccine serotypes or serotype 6A. (Current Controlled Trials number, ISRCTN54494731.)

Evaluation of antiretroviral therapy results in a resource-poor setting in Blantyre, Malawi

Objective  To evaluate treatment results of the paying antiretroviral therapy (ART) clinic of Queen Elizabeth Central Hospital, a large public and teaching hospital in Blantyre, Malawi. The only ART was a fixed drug combination of stavudine, lamivudine and nevirapine.

Dysregulated humoral immunity to nontyphoidal Salmonella in HIV-infected African adults.

HIV and Salmonella HIV-positive individuals who are infected with nontyphoidal strains of Salmonella enterica often succumb to high morbidity and mortality. Why this is the case is unknown. MacLennan et al. (p. 508; see the Perspective by Moir and Fauci) have uncovered a dysregulated antibody response to Salmonella that is the likely culprit. Sera from HIV-infected individuals do a poor job of killing S. Typhimurium, despite surprisingly elevated antibody titers. Experiments showed that HIV-infected serum inhibited the power of normal serum to kill Salmonella. Inhibition was specific to antibodies against lipopolysaccharide (LPS), a component of the cell wall of Salmonella. Hence, HIV-infected sera was able to kill Salmonella strains lacking LPS, and removing LPS immunoglobulin G from infected sera permitted Salmonella killing. Thus, not only does HIV cause defects in cell-mediated immunity but it also seems to impair humoral immunity, with severe consequences for multiple infections. Abnormal antibody responses produced in HIV-infected individuals are ineffective at clearing food-poisoning bacteria. Nontyphoidal Salmonellae are a major cause of life-threatening bacteremia among HIV-infected individuals. Although cell-mediated immunity controls intracellular infection, antibodies protect against Salmonella bacteremia. We report that high-titer antibodies specific for Salmonella lipopolysaccharide (LPS) are associated with a lack of Salmonella-killing in HIV-infected African adults. Killing was restored by genetically shortening LPS from the target Salmonella or removing LPS-specific antibodies from serum. Complement-mediated killing of Salmonella by healthy serum is shown to be induced specifically by antibodies against outer membrane proteins. This killing is lost when excess antibody against Salmonella LPS is added. Thus, our study indicates that impaired immunity against nontyphoidal Salmonella bacteremia in HIV infection results from excess inhibitory antibodies against Salmonella LPS, whereas serum killing of Salmonella is induced by antibodies against outer membrane proteins.

Prevalence of infection with hepatitis B and C virus and coinfection with HIV in medical inpatients in Malawi

BACKGROUND Coinfection with hepatitis B (HBV) or hepatitis C (HCV) adversely affects the prognosis of HIV infection and vice versa, and results in complex interactions with antiretroviral therapy. These infections are common in sub-Saharan Africa but there are few data on prevalence of coinfection. All three components of the most common ART regimen used in Africa, stavudine, lamivudine and nevirapine, can cause hepatic problems and lamivudine resistant HBV is known to emerge after HBV monotherapy in coinfected patients. Point of care (POC) tests for HBV and HCV are widely used but have not been validated in field tests in sub-Saharan Africa. METHODS Prospective observational study of sequential adult inpatients in medical wards of a large urban teaching hospital in Malawi in 2004. Comparison of demographic risk factors with HIV antibody status determined using local double POC test protocols, and with HBsAg and HCV antibody prevalence as estimated in a reference laboratory in Liverpool, UK. Results of locally performed POC tests for HBV using Determine HBsAg (Abbott) and for HCV antibody using HCV-SPOT (Genelabs) were compared with results of reference methods in the UK. RESULTS Of 226 adults (39% male), median (range) age 35 (14-80) years, 81% had a history of traditional scarification, 12% a history of blood transfusion and 11% a history of jaundice. HIV antibodies were present in 76.1%, HBsAg in 17.5% and HCV in 4.5%, with HIV/HBV coinfection in 20.4% and HIV/HCV coinfection in 5% of those with HIV. There was no correlation between prevalence of any of the three viruses and demographic risk factors or presence of either of the other two viruses. Point of care tests gave misleading results with prevalence estimates of 38% for HBV and 4.5% for HCV. For both of these POC tests the performance indices were unacceptable for individual patient management or epidemiological survey purposes. CONCLUSIONS The high prevalence of hepatitis/HIV coinfections may impact on treatment with antiretroviral therapy, especially if there are unintended interruptions of therapy, and studies are needed to document the possible clinical impact on ART programmes. The poor performance of POC tests for HBV and HCV may be due to local operational problems or to unexpected technical issues not revealed by early validation tests. These tests are widely used in resource poor settings and should be revalidated in prospective field studies in areas of the tropics with high HIV prevalence rates.

Impact of HIV-Associated Immunosuppression on Malaria Infection and Disease in Malawi

BACKGROUND Human immunodeficiency virus (HIV) infection and malaria coexist in much of Africa. Previous studies differ in their findings on the interactions between the 2 infections. METHODS Adults living with HIV infection in Blantyre, Malawi, were enrolled in a longitudinal observational study from September 2002 to August 2004. Malaria blood smears were obtained monthly and for any illness suggestive of malaria. Complete evaluations of all illness episodes were conducted, regardless of malaria smear results. RESULTS The incidence of clinical malaria episodes was higher in participants with CD4 cell counts <200 cells/mm3 than in those with CD4 cell counts >500 cells/mm3. The trend was preserved when increasingly specific definitions of malaria disease were used. The prevalence of malaria infection was not associated with CD4 cell count. In per-visit analysis, lower CD4 cell counts were associated with higher incidences of pneumonia, sepsis, and tuberculosis but not of malaria. Severe malaria was rare, with only 3 cases in 591 person-years of observation. Parasite density and CD4 cell count were independent risk factors for fever. CONCLUSIONS Profoundly immunosuppressed adults with HIV infection require more-frequent treatment for uncomplicated malaria, but malaria infection and disease are less strongly associated with HIV-associated immunosuppression than are other opportunistic infections. Where malaria is common, the high incidence of fever found among immunosuppressed adults may lead to misclassification of illness episodes as malaria.

Supplementary feeding with either ready-to-use fortified spread or corn-soy blend in wasted adults starting antiretroviral therapy in Malawi: randomised, investigator blinded, controlled trial.

Objective To investigate the effect of two different food supplements on body mass index (BMI) in wasted Malawian adults with HIV who were starting antiretroviral therapy. Design Randomised, investigator blinded, controlled trial. Setting Large, public clinic associated with a referral hospital in Blantyre, Malawi. Participants 491 adults with BMI <18.5. Interventions Ready-to-use fortified spread (n=245) or corn-soy blend (n=246). Main outcome measures Primary outcomes: changes in BMI and fat-free body mass after 3.5 months. Secondary outcomes: survival, CD4 count, HIV viral load, quality of life, and adherence to antiretroviral therapy. Results The mean BMI at enrolment was 16.5. After 14 weeks, patients receiving fortified spread had a greater increase in BMI and fat-free body mass than those receiving corn-soy blend: 2.2 (SD 1.9) v 1.7 (SD 1.6) (difference 0.5, 95% confidence interval 0.2 to 0.8), and 2.9 (SD 3.2) v 2.2 (SD 3.0) kg (difference 0.7 kg, 0.2 to 1.2 kg), respectively. The mortality rate was 27% for those receiving fortified spread and 26% for those receiving corn-soy blend. No significant differences in the CD4 count, HIV viral load, assessment of quality of life, or adherence to antiretroviral therapy were noted between the two groups. Conclusion Supplementary feeding with fortified spread resulted in a greater increase in BMI and lean body mass than feeding with corn-soy blend. Trial registration Current Controlled Trials ISRCTN67515515.

Ocular disease in patients with tuberculosis and HIV presenting with fever in Africa

Aims: To investigate ocular disease in patients with tuberculosis (TB) and HIV in Africa presenting with fever, and to determine if indirect ophthalmoscopy is useful in the diagnosis of mycobacteraemia. Methods: A prospective study of all adult patients admitted with fever to a large central hospital in Malawi, Africa. All recruited patients had an ophthalmic examination, HIV tests, chest x ray, sputum examinations, bacterial and mycobacterial blood cultures, and malaria slide to observe the presence of parasites. Results: 307 patients were recruited; 109 (36%) had TB, including 53 (17%) with mycobacteraemia; 255 (83%) had HIV and 191 (62%) had AIDS. Of the patients with TB 102 (94%) had HIV. Choroidal granulomas were found in four patients, all of whom had AIDS; three (2.8% of those with TB) had disseminated TB with mycobacteraemia, and one had persistent fever but no other evidence of TB. Among the patients with AIDS, 32 (17%) had microangiopathy manifest by cotton wool spots; one (0.5%) had signs of active cytomegalovirus (CMV) retinitis. The presence of microangiopathy was not related to TB. Conclusions: In Malawian patients with TB presenting acutely with fever, choroidal granulomas were found in 2.8%, and were concurrent with mycobacteraemia and AIDS. Ophthalmoscopy was not a useful aid in the diagnosis of mycobacteraemia. Cytomegalovirus (CMV) retinitis is rarely seen in African AIDS patients. This may be the result of mortality early in the disease course, or differences in race, HIV subtype, or comorbidity.

Glycerol adjuvant therapy in adults with bacterial meningitis in a high HIV seroprevalence setting in Malawi: a double-blind, randomised controlled trial

BACKGROUND Southern Africa has a high incidence of bacterial meningitis in adults, often associated with HIV co-infection. Mortality exceeds 50%, even with appropriate antibiotic therapy, and is not improved with corticosteroids. Glycerol adjuvant therapy reduces long-term morbidity in bacterial meningitis in children, and its use is being promoted. We aimed to assess the effectiveness of glycerol as an adjuvant therapy for adults with bacterial meningitis in Africa. METHODS The study was done in two phases. First, in an open-label dose-finding study, 45 adult patients with symptoms, signs, and cerebrospinal fluid findings consistent with bacterial meningitis received either 50 mL, 75 mL, or 100 mL of glycerol four times a day for 4 days. We then did a randomised, double-blind, placebo-controlled trial of oral glycerol in adults with bacterial meningitis. Patients with clinical and cerebrospinal fluid findings suggestive of bacterial meningitis were randomly assigned in blocks of 12 by use of a random number list produced by an independent statistician to receive either glycerol or an equivalent volume of sugar solution. Glycerol and placebo were indistinguishable by colour or taste. The primary outcome was mortality at 40 days, with secondary outcomes including disability and mortality restricted to pneumococcal disease. All patients were analysed for the primary outcome excluding those who were lost to follow-up. This trial is registered at controlled-trials.com, number ISRCTN70121840. FINDINGS 75 mL glycerol four times a day was the highest tolerated dose, and was used for the main study. 265 patients were assigned treatment: 137 glycerol and 128 placebo. The trial was stopped early on the advice of the data and safety monitoring board after a planned interim analysis. By day 40, 61 (49%) of 125 patients in the placebo group and 86 (63%) of 136 in the glycerol group had died (adjusted odds ratio 2.4, 95% CI 1.3-4.2, p=0.003). There was no benefit from glycerol for death and disability by day 40, and glycerol did not improve death and disability by day 40 or death at day 40 in patients with proven bacterial disease or pneumococcal disease. Two serious adverse events occurred that were possibly due to the study drug. INTERPRETATION Oral glycerol therapy cannot be recommended as an adjuvant therapy in adults with bacterial meningitis in resource-poor settings with a high HIV prevalence. FUNDING Meningitis Research Foundation.

Differential Diagnosis of Stroke in a Setting of High HIV Prevalence in Blantyre, Malawi

Background and Purpose— The differential diagnosis of stroke in Africa in areas with high HIV prevalence includes brain infections. We studied causes of stroke in Blantyre, Malawi, where HIV prevalence among medical inpatients is 70%. Methods— In a descriptive study of 8-month duration, all patients presenting at Queen Elizabeth Central Hospital, Blantyre, with central neurological deficit of acute onset (<24 hours) had baseline investigations, including full blood count, blood glucose, serology for toxoplasmosis, syphilis, and HIV, ECG, echocardiogram, ultrasound of the carotid arteries, and computerized tomography scan of the brain. A lumbar puncture was performed unless contraindicated. Results— Ninety-eight consecutive patients (49 males) were studied. In those who were HIV positive (48%), the mean age was 37.5 years; ischemic stroke was the commonest diagnosis (n=25; 58%), followed by infection (n=11; 23%; including tuberculous [n=4] and cryptococcal [n=2] meningitis; toxoplasmic encephalitis [n=1]; neurocysticercosis [n=1]; brain abscess [n=1]; and progressive multifocal leucoencephalopathy [n=2]). No clinical or laboratory parameters could be identified as predictors for infection, but 3 of 5 patients with fever on admission had tuberculous meningitis. In HIV-negative patients (mean age 58.6 years), 55% had ischemic stroke and 31% had intracerebral hemorrhage; no brain infection was diagnosed. Presence of vascular disease correlated with age but not with HIV status. Conclusions— Ischemic stroke was found in half of patients irrespective of HIV status. In those who are HIV positive, brain infection should be considered for which the presence of fever and examination of cerebrospinal fluid seem most useful in diagnosis.