Background:

Pre-surgical oral hygiene (POH) with tooth brushing has been established to prevent infectious complications. The need of an additional cleansing with chlorhexidine is questionable.

Objective:

To establish the level of pharyngeal bacterial colonization according to compliance with POH and the additional impact of a chlorhexidine rinse.

Methods:

Study with patients 18 years and older scheduled for surgery. Two phases: first, we evaluated the level of colonization (mild-moderate-severe) according to compliance or not with the POH, and second, to a randomly assigned rinse (or not) with 15 mL of chlorhexidine (0.12%). The presence of pathogenic agents was analyzed.

Results:

48/60 (80%) did not comply with the POH. All had moderate to high colonization, but compliers had a lower proportion of high colonization (16.7 versus 33.3%, p = 0.23). After cleansing with chlorhexidine (30 patients), 1/6 (16%) with POH continued with high colonization, the rest fell to moderate; 20% (5/24) without POH continued with high colonization, 70% (17/24) fell from high to moderate and two (8%) from high to mild; one (4%) with moderate pre-chlorhexidine colonization decreased to mild. Only six patients without POH (12.6%) had S. aureus or S. pneumoniae isolated. Chlorhexidine reduced colonization from high to moderate in three with S. aureus, in the other, it remained high. Chlorhexidine reduced colonization from high to moderate in one of the two patients with S. pneumoniae.

Conclusion:

Compliance with POH reduces pharyngeal colonization, especially of pathogenic bacteria. The addition of a rinse with chlorhexidine can increase this protection.