Aim: Topical vancomycin applied to the oropharynx has been shown to control carriage and lower airway infection due to methicillin-resistant Staphylococcus aureus (MRSA). We undertook a three-year prospective observational study to evaluate the effectiveness of two policies for topical vancomycin administration on oropharyngeal carriage and lower airway infection due to MRSA in patients requiring mechanical ventilation.
Methods: All consecutive patients aged over 18 years and expected to require mechanical ventilation for more than 72 hours were enrolled. During period one, patients who were established MRSA carriers received 1 g of 4% vancomycin gel into the oropharynx four times a day until carriage was abolished. During period two, all enrolled patients received the same protocol immediately on admission, irrespective of their MRSA carrier state.
Results: One hundred ninety-one patients met the entry criteria (98 in period one and 93 in period two). During period one, 40 patients developed oropharyngeal MRSA carriage; of these, 29 acquired MRSA in the unit. In contrast, MRSA carriage was not demonstrated during period two (relative risk [RR] 0.018, 95% confidence interval [CI] 0-0.29; P=0.004). Twenty-one patients from period one suffered from an Intensive Care Unit-acquired lower airway infection due to MRSA, compared with five patients from period two (RR 0.25, 95% CI 0.10-0.64, P=0.004). Vancomycin-intermediate Staphylococcus aureus and vancomycin-resistant enterococci were not isolated.
Conclusion: In the setting of MRSA endemicity, the prevention of MRSA carriage by topical oropharyngeal vancomycin was more effective in reducing carriage and infection of the lower airways than treatment of established carriers.