Diagnostic accuracy of protected specimen brush and bronchoalveolar lavage in nosocomial pneumonia: Impact of previous antimicrobial treatments

Abstract

After recent introduction of an antibiotic treatment for suspected ventilator-associated pneumonia, protected specimen brush and bronchoalveolar lavage culture thresholds must be decreased to maintain good accuracy. In contrast, current antibiotic treatment prescribed for a prior infectious disease does not modify the diagnostic accuracy of protected specimen brush or bronchoalveolar lavage.

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

“…In a study of 76 patients with VAP by Montravers et al, PSB quantitative cultures obtained after the administration of effective antibiotic therapy showed complete eradication of the causative organisms after only 3 days of treatment in 67% of patients (150). Even 24 h of administration of an antibiotic can affect culture results (189). This effect of prior antibiotics on the false-negative rate of microbiologic studies is of great concern, particularly since VAP is a potentially lethal disorder.…”

“…This effect of prior antibiotics on the false-negative rate of microbiologic studies is of great concern, particularly since VAP is a potentially lethal disorder. However, if antibiotics have not been changed in the last 72 h, the diagnostic yield of any culture technique is unaffected (189,197).…”

Pathophysiology of Escherichia coli ventilator-associated pneumonia: implication of highly virulent extraintestinal pathogenic strains

“…Antimicrobial agents were given in these patients because VAP was strongly suspected in view of a low PaO 2 /FiO 2 ratio with new radiological infiltrate, no other site of infection, and favorable outcome with appropriate anti-E. coli agents. Of note, lung microbiological sampling in these patients was performed while patients had already started receiving antibiotics for VAP suspicion, a situation in which thresholds of bacterial count should be reduced to maintain validity [28].…”

Diretrizes brasileiras para tratamento das pneumonias adquiridas no hospital e das associadas à ventilação mecânica - 2007

“…A exposição a antibió-ticos aumentou significativamente o risco de óbito (OR = 9,2; p < 0,0001), porém, este efeito ocorreu primariamente pela seleção de microorganismos multiresistentes, único fator independentemente associado a este risco. (66,67) , Entretanto , estudo prospectivo de 63 episódios suspeitos de PAVM, sugeriu que estes pontos de corte deveriam ser reduzidos para 10 2 UFC/mL, e 10 3 UFC/mL para o EP e LBA, respectivamente, em pacientes em uso de antibió-ticos há menos de 24 h. (68) Um estudo brasileiro demonstrou que mesmo quando o paciente já está sob tratamento antimicrobiano, o AET com cultura quantitativa foi útil para a identificação do agente causador de PAVM. (69) …”