Enterocolitis, síndrome urémico hemolítico y antibióticos...
BACKGROUND Bacterial enterocolitis (Escherichia coli, Shigella, Salmonella species and other) are a common health problem worldwide, with different implications according to the geographical and socio-economical settings as well as age groups. Developing countries pose several particular features such as their high risk of these infections in children and the variable availability of early etiological diagnosis aids by identification of the causal agent. Although the use of antibiotics may be controversial, some types of syndromes and settings make their use mandatory (1,2). An earlier publication in the made ten years ago (3) exhibited data showing a strong association between Escherichia coli O157:H7 infections treated with antibiotics and the development of haemolytic-uremic syndrome (HUS) leading their authors to “recommend against giving antibiotics to children who may be infected with Escherichi coli O157:H7 until the results of a stool culture indicate that the pathogen responsible is one appropriately treated by an antibiotic” (3). This study, presented as an analytic design (a prospective cohort study) showed a 17.3 relative risk (95 confidence interval 2.2 to 137), a figure that proved menacing to Latin America paediatricians and those of developing countries, working in places where bacterial enterocolitis are an outstandingly prevailing health problem. In these settings other than common laboratory resources for bacterial identification are usually not at hand, what elicited an immediate comment pointing that “we worry that the message of this study will be extended prematurely to the treatment of bloody diarrhea worldwide” (4). In such instances withholding antibiotic therapy would have more risks tan benefits since bacterial enterocolitis E.Coli infection occur in a scenario where E.coli, Shighella as well as E.coli other tan O157:H7 have similar prevalence (4). After more than ten years have elapsed since the first statement, the widespread notion that treating children's diarrhea with antibiotics entails a high risk has become a common place (5 -11), what hampers pediatric decisions making and prevents randomized controlled trials proposals which might solve this and other issues related with both enterocolitis, SHU and antibiotic therapies in bacterial entrerocoilitis. In other words, two phenomena seem to have occurred: 12
Análisis Crítico
a) the generalization of the E.coli O157:H7- related risk concept into pediatric clinical practice encompassing other bacterial etiologies (5) and b) the equipoise(12) unbalance brought by Wong et al. statement this way preventing eventual interventional designs in these subjecst. (12) A previous review on the same topic had been carried out by us but not published (13) that found no evidence supporting the Wong et al. recommendation. We therefore carried out a new literature review addressed to: a) look at whether more recent studies relating E.coli O157:H7 enterocolitis, antibiotic treatment and SHU might contribute to solve this clinical crossroads and b) bring the equipoise status to its right balance, so as to make randomized control trial (RCT) proposals acceptable. It was not our aim to looking for basis to advocate the systematic use of antibiotics in children with bacterial enterocolitis. METHODS Following standard methods for clinical reviews (14), we searched studies identified by the words “Escherichia coli O157:H7”, “antibiotics”, “haemolytic-uremic syndrome” and “children (all)” by means of PubMed for an arbitrary period ranging from June 30, 1990 to March 31, 2011. Cochrane database was also searched for RCTs and hand-selection of articles was performed from the selected articles references lists. We decided to use the “enterocolitis” term to skip misunderstandings due to the terminology used for infectious diarrheal syndromes in the literature and field work, avoiding the “bloody” character required earlier as a risk factor of SHU ( since it is not always present. Three of us (PH, CV, MS) classified the articles in one of the following design cathegories: clinical controlled trial, prospective cohorts, case-control, one-cohort studies, case series as well as their statistical analysis, following standard methods (15, 16). Differences among participants were solved by agreement. Since almost none of the studies previously reviewed included a formal, explicit hypothesis to be tested so random errors level, Po (value under the null hypothesis), size of expected association statistics and sample size calculations were lacking. “Crude” data from the study texts and tables were extracted to make primary calculations to assessing results, as has been proposed Revista Medicina Vol. 10 No. 1 Enterocolitis, síndrome urémico hemolítico y antibióticos: ¿un asunto no resuelto? Pág. 2 de 11