Difficulties encountered in a community-based study of acute respiratory infections in Uruguay

A cohort study on acute respiratory infections, involving 270 children observed by pediatricians in their homes every 10 days over a period of 32 months, gave the opportunity to experience logistic and methodological problems seldom described in the literature. The purpose of this article is to alert researchers as to the difficulties faced when performing community-based studies in developing countries. Although a carefully planned project was undertaken, problem areas included the establishment of the target population, population dynamics, field related problems, laboratory aspects and data management. It is hoped that other investigators may benefit from the extensive experience gained from our program in foreseeing and coping with the difficulties involved.

Immuno-epidemiology of Schistosoma mansoni infections in a recently exposed community in Senegal

The levels of IgE and IgG4 increased strongly between cohorts, indicating a dynamic immunological situation, but no immediate impact on infection levels. Morbidity was little specific abdominal discomfort was reported by 61%, diarrhoea by 33% of the subjects; mild hepatomegaly was found in 16%, splenomegaly in 0.5%. No relation to egg counts was observed for any symptom. This mild morbidity may be due to the recent nature of the focus. In the first cohort, the percentage of people with negative egg counts ten weeks after treatment was only 18%, though egg counts declined strongly. Antigen detection confirmed these results. Praziquantel treatment provoked transient but impressive side effects (colics, vomiting, urticaria, aedema), the occurrence of which correlated with intensity of infection. Cure rates in subsequent cohorts were followed up shorter after treatment but remained low. Reinfection nevertheless oppears limited. This lower drug efficacy may be due to very rapid reinfection and/or to the lack of immunity in the population, but also reduced susceptibility of the local parasite strain must be considered and studied.

Bloodstream infections in late-stage acquired immunodeficiency syndrome patients evaluated by a lysis centrifugation system

Opportunistic infections, which affect acquired immunodeficiency syndrome (Aids) patients, are frequently disseminated and may cause bloodstream infections (BSI). The aim of this study was to evaluate the main causes of BSI in Aids patients with advanced stage of the disease, with special emphasis on the identification of fungemia. During a 21 months period, all patients with Aids (CD4 < 200) and febrile syndrome admitted to 3 university hospitals were systematically evaluated. For each patient presenting fever, a pair of blood cultures was collected and processed by using a commercial lysis-centrifugation system. One hundred and eleven patients (75 males) with a mean age of 36 years (median 33 years) and mean CD4 count of 64 cells/ml were included. Among the 111 patients evaluated we documented 54 episodes of BSI, including 46 patients with truly systemic infections and 8 episodes considered as contaminants. BSI were caused by gram-positive bacteria (43%), fungi (20%), gram-negative bacteria (15%), mycobacteria (15%), and mixed flora (7%). The crude mortality rate of our patients was 39%, being 50% for patients with BSI and 31% for the others. In conclusion, BSI are a common related to systemic infections on Aids patients with advanced stage of disease and is associated with a high rate of mortality.

Estimating attributable mortality due to nosocomial infections acquired in intensive care units.

BACKGROUND: The strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken. OBJECTIVE: To assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients. SETTING: Eleven ICUs of a French university hospital. DESIGN: We analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was defined as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis. RESULTS: Among 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%-14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%-6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%-3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%-2.5%) for bloodstream infection, and 0.0% (95% CI, -0.4% to 0.4%) for urinary tract infection. CONCLUSIONS: ICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.

Relationship among epidemiological parameters of six childhood infections in a non-immunized Brazilian community

Epidemiological parameters, such as age-dependent force of infection and average age at infection () were estimated for rubella, varicella, rotavirus A, respiratory syncytial virus, hepatitis A and parvovirus B19 infections for a non-immunized Brazilian community, using the same sera samples. The for the aforementioned diseases were 8.45 years (yr) [95% CI: (7.23, 9.48) yr], 3.90 yr [95% CI: (3.51, 4.28) yr], 1.03 yr [95% CI: (0.96, 1.09) yr], 1.58 yr [95% CI: (1.39, 1.79) yr], 7.17 yr [95% CI: (6.48, 7.80) yr] and 7.43 yr [95% CI: (5.68, 9.59) yr], respectively. The differences between average ages could be explained by factors such as differences in the effectiveness of the protection conferred to newborns by maternally derived antibodies, competition between virus species and age-dependent host susceptibility. Our seroprevalence data may illustrate a case of the above-mentioned mechanisms working together within the same population.

Characteristics and determinants of outcome of hospital-acquired bloodstream infections in intensive care units: the EUROBACT International Cohort Study.

PURPOSE: The recent increase in drug-resistant micro-organisms complicates the management of hospital-acquired bloodstream infections (HA-BSIs). We investigated the epidemiology of HA-BSI and evaluated the impact of drug resistance on outcomes of critically ill patients, controlling for patient characteristics and infection management. METHODS: A prospective, multicentre non-representative cohort study was conducted in 162 intensive care units (ICUs) in 24 countries. RESULTS: We included 1,156 patients [mean ± standard deviation (SD) age, 59.5 ± 17.7 years; 65 % males; mean ± SD Simplified Acute Physiology Score (SAPS) II score, 50 ± 17] with HA-BSIs, of which 76 % were ICU-acquired. Median time to diagnosis was 14 [interquartile range (IQR), 7-26] days after hospital admission. Polymicrobial infections accounted for 12 % of cases. Among monomicrobial infections, 58.3 % were gram-negative, 32.8 % gram-positive, 7.8 % fungal and 1.2 % due to strict anaerobes. Overall, 629 (47.8 %) isolates were multidrug-resistant (MDR), including 270 (20.5 %) extensively resistant (XDR), and 5 (0.4 %) pan-drug-resistant (PDR). Micro-organism distribution and MDR occurrence varied significantly (p < 0.001) by country. The 28-day all-cause fatality rate was 36 %. In the multivariable model including micro-organism, patient and centre variables, independent predictors of 28-day mortality included MDR isolate [odds ratio (OR), 1.49; 95 % confidence interval (95 %CI), 1.07-2.06], uncontrolled infection source (OR, 5.86; 95 %CI, 2.5-13.9) and timing to adequate treatment (before day 6 since blood culture collection versus never, OR, 0.38; 95 %CI, 0.23-0.63; since day 6 versus never, OR, 0.20; 95 %CI, 0.08-0.47). CONCLUSIONS: MDR and XDR bacteria (especially gram-negative) are common in HA-BSIs in critically ill patients and are associated with increased 28-day mortality. Intensified efforts to prevent HA-BSIs and to optimize their management through adequate source control and antibiotic therapy are needed to improve outcomes.

The efficacy of amoxycillin/clavulanate (Augmentin) in the treatment of severe staphylococcal infections.

The experimental and clinical values of amoxycillin/clavulanate in severe Staphylococcus aureus infections are reviewed. Experimentally, amoxycillin/clavulanate was highly effective in the treatment of acute endocarditis due to methicillin-sensitive isolates of S. aureus (MSSA) in rats. In addition, high doses of amoxycillin/clavulanate also cured experimental endocarditis due to methicillin-resistant strains of S. aureus (MRSA) in the animal model. In the clinical setting, a review of 86 patients with either community- or hospital-acquired bacteraemia due to MSSA showed that intravenous treatment with amoxycillin/clavulanate was adequate for empirical (and apparently also long-term) therapy of such severe infections. However, the retrospective nature of the analysis did not allow assessment of the relative efficacy of amoxycillin/clavulanate as compared with standard anti-staphylococcal drugs, such as flucloxacillin or vancomycin. Further prospective studies are warranted to address this issue. Thus, amoxycillin/clavulanate appears to be a good candidate for empirical treatment of severe infections that may be caused by MSSA. Usage of amoxycillin/clavulanate against MRSA is, however, still experimental and is not currently advocated for the treatment of MRSA infections in humans.

Traitement des infections urinaires simples: impact des résistances antibiotiques croissantes dans la communauté [Uncomplicated urinary tract infections: impact of increasing antibiotic resistance in the community].

Uncomplicated urinary tract infections are commonly encountered in primary care and frequently lead to empirical antibiotic prescriptions. The development of antibiotic resistance in the community explains treatment failures observed with commonly-prescribed drugs such as quinolones and co-trimoxazole. This article describes the epidemiology of antibiotic resistance among pathogens causing uncomplicated urinary tract infections and the consequences in terms of recommendations for empirical antibiotic therapy.

Resistance of Santa Ines, Suffolk and Ile de France sheep to naturally acquired gastrointestinal nematode infections

A study was conducted to assess the breed resistance against nematode infections in Santa Ines, Ile de France and Suffolk male lambs over a 9-month period in São Paulo state, Brazil. Lambs were born during the winter (year 2000) and were weaned at 2 months of age. The animals were then housed and treated with anthelmintics to eliminate natural infections by gastrointestinal nematodes. In late October 2000, lambs were placed in a paddock, where they stayed until August of the following year. Fecal and blood samples were taken from each animal every 2 weeks. on the same day, a pasture sample was collected to determine the number of infective larvae on the herbage. To prevent deaths, individual treatment with anthelmintics was provided to lambs with fecal egg counts (FEC) higher than 4000 eggs per gram (EPG) or with a packed cell volume (PCV) lower than 21%. In August 2001, all animals were slaughtered and the worms present in samples of the gastrointestinal contents were identified and counted. Most of the Suffolk and Ile de France sheep received three to six anthelmintic treatments over a period of 7 months, while most of the Santa Ines were not treated. Reductions in PCV and plasma protein values associated with high FEC and worm burdens were recorded, particularly, in Suffolk and Ile de France lambs. Haemonchus contortus and Oesophagostomum columbianum burdens and number of nodular lesions caused in the large intestine by O. columbianum larvae were significantly lower in Santa Ines sheep. All three breeds showed similar Trichostrongylus colubriformis worm burdens. The relative resistance of Santa Ines young male sheep was superior to that of Suffolk and Ile de France sheep. (C) 2004 Elsevier B.V. All rights reserved.

Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Community-associated methicillin-resistant Staphylococcus aureus in non-outbreak skin infections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Community-associated methicillin-resistant Staphylococcus aureus in non-outbreak skin infections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Depletion of Langerhans cells in the tongue from patients with advanced-stage acquired immune deficiency syndrome: relation to opportunistic infections

Aims: To quantify and compare the expression of Langerhans cells (LCs) in the tongue mucosa of AIDS patients with different opportunistic infections, and from acquired immune deficiency syndrome (AIDS) and non-AIDS patients with normal tongues, using autopsy material. Methods and results: Human leucocyte antigen D-related (HLA-DR), CD1a and CD83 antibodies were used to identify and quantify LCs by immunohistochemistry in tongue tissue of 40 AIDS patients (10 with lingual candidiasis, 10 with lingual herpes, 10 with oral hairy leukoplakia and 10 with no lesions) and 23 tongues from human immunodeficiency virus (HIV)negative control patients. Quantification was performed by means of conventional morphometry in four different regions (anterior, middle, posterior and lateral) of the tongue. The results were expressed as positive cells per area of epithelium. The AIDS patients presented a lower density of CD1a(+) cells (P < 0.001), HLA-DR (P < 0.003) and CD83 (P < 0.001) in all regions of the tongue compared to the non-AIDS control group. However, no differences in any of the markers were found when AIDS patients with different opportunistic infections were compared with AIDS patients without tongue infection. Conclusions: Advanced stage AIDS patients showed a depletion of LCs in the tongue mucosa. HIV infection induces cytopathic changes in LCs, contributing to their depletion regardless of the presence of oral infections.

Isolation of human bocavirus from Swiss infants with respiratory infections

Human bocavirus (HBoV) is a novel agent associated with respiratory symptoms in adults and children. We studied prospectively the first acute respiratory infection in a birth cohort of healthy neonates in Switzerland. HBoV was identified in 5 (4.5%) of 112 infants as young as 3 months of age. In 4 of the 5 infants, HBoV was associated with other respiratory viruses. We conclude that HBoV circulates in the community and is acquired early in life.