Diagnostic accuracy of oropharyngeal cultures in infants and young children with cystic fibrosis

Abstract

The objective of this study was to assess the diagnostic accuracy of oropharyngeal (OP) cultures relative to simultaneous bronchoalveolar lavage (BAL) cultures in very young children with CF, and to examine the effects of bacterial density, age, and study cohort on diagnostic accuracy. Respiratory culture data were analyzed from three independent, prospective studies involving simultaneous collection of 286 OP and BAL cultures from 141 children with CF <5 years of age. For predicting any growth of Pseudomonas aeruginosa (Pa) from the lower airway in subjects ≤18 months of age (mean age, 8 ± 5 months), OP cultures had a sensitivity of 44% (95% CI 14%, 79%), specificity of 95% (90%, 99%), positive predictive value of 44% (14%, 79%), and negative predictive value of 95% (90%, 99%). Diagnostic accuracy was similar for Haemophilus influenzae (Hi). Specificity was significantly lower for Staphylococcus aureus (Sa). Sensitivity for all organisms improved if a positive lower airway culture was defined as ≥103 or ≥105 cfu/mL. Specificity for Pa declined significantly with increasing age. In children with CF <5 years of age, the specificity and negative predictive value of OP cultures for Pa are high, while the sensitivity and positive predictive value are poor. Thus, in this age range, a negative throat culture is helpful in “ruling out” lower airway infection with Pa. However, a positive culture does not reliably “rule in” the presence of Pa in the lower respiratory tract. These findings may have implications for study design and interpretation as well as clinical management of young children with CF. Pediatr Pulmonol. 1999;28:321–328. © 1999 Wiley‐Liss, Inc.

Sputum induction in young cystic fibrosis patients

“…This is approximately the rate reported in the US Cystic Fibrosis Foundation Data Registry in 1995 (34% at 5 yrs of age and 52% in 10 yr olds); however, in the US database, it is not specified what sample is assessed. In the study of ROSEN-FELD et al [25] the Pseudomonas spp. carrier rate is 31% at the age of 31±52 months.…”

Prevalência de bactérias potencialmente patogênicas em espécimes respiratórios de fibrocísticos do Recife

“…Recentes instruções da Fundação Norte Americana de Fibrose Cística recomendam a necessidade de se usar o meio ágar sal manitol na rotina bacteriológica de espécimes de fibrocísticos (17) . Embora a cultura de espécimes faríngeos seja recomendada como uma alternativa à cultura para os fibrocísticos incapazes de fornecer escarro (17) , alguns estudos comparativos mostram que os espécimes faríngeos são inferiores ao escarro ou lavado bronco-alveolar no diagnóstico bacteriológico de infecções pulmonares naqueles pacientes (1,16) . No presente trabalho, a avaliação da acurácia das culturas de faringe não foi possível já que não se submeteu o mesmo participante, após a coleta do swab faríngeo, a controle pela realização de lavado bronco-alveolar.…”

Infection Prevention and Control Guideline for Cystic Fibrosis: 2013 Update

“…The positive and negative predictive values of deep throat specimens or oropharyngeal specimens for the lower airway specimens have been studied with varying results, presumably due to the different patient populations and pathogens studied. 42 The yield of induced sputum relative to upper airway specimens has also been assessed in research settings, and induced sputum generally yields more potential pathogens. 43 The 2003 Infection Control Guideline for CF recommendations for processing all types of respiratory tract specimens (throat, sputum, or bronchoalveloar lavage) continues to be appropriate.…”

“…Specimens obtained from the upper airway lack sensitivity and specificity for the lower airway. 42 Despite standardized protocols for processing CF specimens, potential pathogens may escape detection due to low organism burden, overgrowth by other species, or misidentification. 1,447 Genotyping studies have also demonstrated the potential for replacement of an initial infecting Burkholderia strain with another strain (ie, superinfection) when CF patients have been segregated into groups on the basis of infection status.…”