Streptococcus pneumoniae and Haemophilus species colonization in health care workers: the launch of invasive infections?

Background: Streptococcus pneumoniae and Haemophilus influenzae are important human pathogens. The risk of airborne and droplet-transmitted respiratory tract infections in healthcare workers (HCW) is substantial. The aim of this study was to determine the extent of oropharyngeal colonization with S. pneumoniae and Haemophilus spp. their antibiogram and risk factors of colonization in HCW at a tertiary care center, Western Nepal.

Methods: During 3 month period, 100 oropharyngeal swab specimens were collected from HCW of Manipal Teaching Hospital and 50 from non HCW from community. All the 150 specimens were screened for Haemophilus spp. and S. pneumoniae by standard techniques. Serotyping of H. influenzae type b was done by using specific antiserum. Antibiotic sensitivity patterns of isolates were determined by modified Kirby Bauer disc diffusion method. Association between the groups was analyzed using the Pearson χ(2) test and Fisher exact test. A forward step logistic regression model was used to identify significant predictors for colonization.

Result: Sixty-five percent of HCW were colonized with S. pneumoniae and/or Haemophilus species compared to 32 % of non-HCW. Health care workers had odd ratio (OR) 3.946 [CI (1.916, 8.128)] times more tendency of colonization compared to non-HCW (P < 0.05). Pneumococcal colonization was observed high among smokers (81.5 %). Amongst HCW, post graduate resident doctors had higher rate of colonization (83.3 %) followed by interns (64.9 %), least being amongst the laboratory workers (58.3 %).

Conclusion: The higher rate of colonization amongst HCW raises the possibility of occupational risk as well as horizontal spread of infections.