Correlation between preceding respiratory virus or Mycoplasma pneumoniae infections and nasopharyngeal colonization in children with acute respiratory tract infection

Abstract

Objective To elucidate the correlation between preceding respiratory virus or Mycoplasma pneumoniae(MP) infections and bacterial colonization of the nasopharynx. Methods A total of 8 322 children hospitalized with acute respiratory tract infection from Jan.2006 to Dec.2010 in Children's Hospital Affiliated to Soochow University were enrolled.Nasopharyngeal aspiration fluid and serum samples were collected and sent for multi-pathogen detection.Respiratory syncytial virus (RSV), influenza virus type A(IV-A) and influenza virus type B (IV-B), parainfluenza virus type 1-3 (PIV 1-3) and Adenovirus (ADV) were detected by direct immunofluorescence assay.MP were detected by polymerase chain reaction (PCR) while human metapneumovirus (hMPV) was detected by reverse transcription polymerase chain reaction.Sputum culture was used to detect bacterial colonization and quantitative enzyme linked immunosorbent assay was used to detect specific antibodies of MP.Correlations between preceding respiratory virus or MP infections and bacterial colonization were analyzed using Spearman correlation coefficient. Results At time 0 month, only Moraxella catarrhalis was significantly correlated with RSV (rs=0.270, P=0.035) and the correlation increased slightly at 1 month lag (rs=0.290, P=0.024). There was significant correlation between RSV (rs=0.370, P=0.004) or hMPV (rs=0.350, P=0.006) and hemophilus influenza at 1 month lag with a stronger correlation at 2 months lag.For IV-A, there was negative correlation with Streptococcus pneumoniae at 1 month lag (rs=-0.339, P=0.009) as well as there was negative correlation between ADV and Streptococcus pneumoniae (rs=-0.269, P=0.040). At 1 month lag, negative correlation was present between ADV and Moraxella catarrhalis (rs=-0.300, P=0.021) and the correlation was stronger at 2 month lag (rs=-0.380, P=0.003). Conclusions To some extent, there are temporal associations between preceding respiratory virus and MP infections and nasopharyngeal colonization, furthermore lag effect was found between RSV, hMPV, IV-A, ADV, MP and bacterial colonization. Key words: Acute respiratory tract infection; Respiratory virus; Mycoplasma pneumoniae; Bacterial colonization; Child