To analyze factors that can interfere with blood culture results in a pediatric population, as there are few reports of standardization of procedures for blood culture in pediatrics. Methods: We analyzed 100 blood samples collected during 3 months at the Pediatric Intensive Care Unit at the Hospital das Clínicas of the Medical School, Campinas State University (UNICAMP), Brazil. Factors studied were: site and procedure for blood collection, patient's age, clinical diagnosis, type of antiseptic substance used, and amount of blood withdrawn for sample. Results: Two samples were sufficient to diagnose bacteremia. The positivity of the samples was associated with the age of the patients. The rate of contamination associated with the total number of samples was 5%. All the false-positive samples were collected from children younger than 1 year. Blood culture diagnosed bacteremia by multiresistant agents even in patients using antibiotics. Conclusions: The contamination of the samples (false-positive samples) was associated with the age of the children, probably because of the difficulty to collect the blood. The interference of antibiotics was demonstrated, especially in pediatric intensive care units. Blood culture was useful in identifying multiresistant agents in children being treated with broad-spectrum antibiotics. Because of the importance of blood culture and the knowledge of factors that can interfere with the results, physicians should be critical of indication and manner of sample collection to avoid iatrogenic problems.
MethodsWe analyzed 100 blood samples collected during 3 months at the Pediatric Intensive Care Unit at the Hospital das Clínicas of the Medical School, Campinas State University (UNICAMP), Brazil. Factors studied were: site and procedure for blood collection, patient's age, clinical diagnosis, type of antiseptic substance used, and amount of blood withdrawn for sample. Results: Two samples were sufficient to diagnose bacteremia. The positivity of the samples was associated with the age of the patients. The rate of contamination associated with the total number of samples was 5%. All the false-positive samples were collected from children younger than 1 year. Blood culture diagnosed bacteremia by multiresistant agents even in patients using antibiotics. Conclusions: The contamination of the samples (false-positive samples) was associated with the age of the children, probably because of the difficulty to collect the blood. The interference of antibiotics was demonstrated, especially in pediatric intensive care units. Blood culture was useful in identifying multiresistant agents in children being treated with broad-spectrum antibiotics. Because of the importance of blood culture and the knowledge of factors that can interfere with the results, physicians should be critical of indication and manner of sample collection to avoid iatrogenic problems.
ResultsTwo samples were sufficient to diagnose bacteremia. The positivity of the samples was associated with the age of the patients. The rate of contamination associated with the total number of samples was 5%. All the false-positive samples were collected from children younger than 1 year. Blood culture diagnosed bacteremia by multiresistant agents even in patients using antibiotics. Conclusions: The contamination of the samples (false-positive samples) was associated with the age of the children, probably because of the difficulty to collect the blood. The interference of antibiotics was demonstrated, especially in pediatric intensive care units. Blood culture was useful in identifying multiresistant agents in children being treated with broad-spectrum antibiotics. Because of the importance of blood culture and the knowledge of factors that can interfere with the results, physicians should be critical of indication and manner of sample collection to avoid iatrogenic problems.
ConclusionsThe contamination of the samples (false-positive samples) was associated with the age of the children, probably because of the difficulty to collect the blood. The interference of antibiotics was demonstrated, especially in pediatric intensive care units. Blood culture was useful in identifying multiresistant agents in children being treated with broad-spectrum antibiotics. Because of the importance of blood culture and the knowledge of factors that can interfere with the results, physicians should be critical of indication and manner of sample collection to avoid iatrogenic problems.
Analisar fatores que podem interferir no resultado de hemocultura em uma população pediátrica, face à existência de poucos relatos de padronização de hemocultura em Pediatria.
MétodosDurante três meses, 100 amostras de hemoculturas, colhidas na Unidade de Terapia Intensiva Pediátrica do H.C./UNICAMP foram analisadas em relação a local e modo de coleta, idade dos pacientes, diagnóstico clínico, tipo de antisséptico utilizado, uso prévio de antibiótico e volume de sangue coletado por amostra.
ResultadosDuas amostras de hemocultura foram suficientes para o diagnóstico de bacteremia. A positividade das amostras teve relação com a idade dos pacientes. A taxa de contaminação, em relação ao número total de amostras, foi de 5%. Todas as amostras falso-positivas foram colhidas em menores de um ano de idade. A hemocultura diagnosticou bacteremia por agentes multirresistentes, mesmo nos pacientes que faziam uso de antibiótico.
ConclusãoA contaminação das amostras (ou falso-positivos) teve relação com a idade dos pacientes e, possivelmente, com as dificuldades técnicas para a coleta da amostra de sangue. Ficaram demonstradas, também, a interferência da antibioticoterapia na positividade das hemoculturas e, principalmente, para os pacientes em terapia intensiva, a importância das hemoculturas quando o paciente está em uso de antibiótico, para a identificação de microrganismos multirresistentes. Devido à importância da hemocultura, conhecendo-se os fatores que interferem no resultado, deve-se realizar uma análise crítica em relação a indicação e coleta do exame, para evitar iatrogenias para os pacientes.
