Changes in dental plaque following hospitalisation in a critical care unit: an observational study

Previous research has suggested that deterioration in oral health can occur following hospitalisation. The impact of such deterioration could increase the risk of oral disease, reduce quality of life and increase the potential for healthcare-associated infections (HCAI) such as healthcare-associated pneumonia (HAP). However, the strength of the evidence is limited by, amongst other factors, the few observational studies published that assess oral health longitudinally. In view of the microbiological component of oral diseases and HCAIs, the objective of this study was to investigate the microbiological changes in dental plaque following hospitalisation in a Critical Care Unit (CCU): (1) total number of cultivable bacteria and (2) presence and changes in specific HAP pathogens.

We conducted a prospective, longitudinal observational study in the CCU of University College Hospital, London. Study participants were recruited within 24 hours of admission. Dental plaque samples were collected from up to six sites per patient. The primary outcome was microbiological change from baseline to seven days with additional analysis for participants still present at day 14.

50 patients were recruited with 36 available for review at one week, with early discharge accounting for much of the loss to follow-up. The median total viable count of the plaque microbiota at baseline was 4.40 × 105 cfu/ml and increased at week one to 3.44 × 106 cfu/ml. The total viable microbe counts increased by a median of 2.26 × 106 cfu/ml from baseline to week one (95% CI: 3.19 × 106, 1.24 × 107) and this was statistically significant (P < 0.01). Specific HAP bacteria were detected in 26% of participants sampled, although accounted for a relatively low proportion of the total viable bacteria.

Total bacterial count of dental plaque increases during hospitalisation in CCU. This finding, together with the colonisation of dental plaque by HAP bacteria strengthens the evidence for a deterioration in oral health in CCU and a risk factor for negative health and quality of life outcomes.