S. aureus/MRSA are Associated with Heavy Plaque; Pneumonia is not

Objectives:

1. Investigate association between hospital acquired pneumonia (HAP) and tooth number, quantity of dental/denture plaque and oral colonisation with respiratory pathogens (OCRP)

2.  Investigate association between OCRP and heavier plaque

Methods:

93 orthopaedic patients (age >65) admitted with lower limb fracture were followed prospectively for diagnosis of HAP until 3 months after discharge.  Tongue and throat swabs, dental /denture plaque scores, functional indices and medical data were collected.  Plaque was scored visually (modified Quigely Hein index) at the bedside.  Major respiratory bacterial pathogens (see Table) were identified using a novel multiplex real-time PCR assay.  The relationship between pneumonia and dental/OCRP/demographic variables (Fisher's exact test), and the relationship between OCRP and dental/demographic variables (generalised linear modelling) were investigated.

Results:

Charlson comorbidity index* and proportion of swabs positive for S. aureus** and MRSA*were significantly associated with cases of pneumonia up to 3 months after discharge.  Considering cases of pneumonia in hospital only, age*, proportion of swabs colonised with S. aureus* and MRSA* were significantly associated. 

Table.  Generalised linear modelling relating OCRP and patient characteristics, best models

*p<0.05, **p<0.01

Conclusions:

HAP was not associated with increased quantities of dental or denture plaque, nor number of teeth.  Presence of S. aureus, and host vulnerability factors were significantly more common in those who developed pneumonia.  Only S. aureus and MRSA were associated with higher admission plaque scores.  Dental/denture plaque could be a target for prevention of oral colonisation with S. aureus and MRSA.