Reduction in Gram-positive pneumonia and antibiotic consumption following the use of a SDD protocol including nasal and oral mupirocin

Abstract

The objective of this prospective, randomized, double-blind study was to evaluate the effect of the addition of mupirocin to the ‘classical’ topical SDD regimen (tobramycin 80 mg, polymyxin E 100 mg, amphotericin B 500 mg) on the development of ICU-acquired infections due to Gram-positive bacteria. The study was carried out in an intensive care unit (ICU) of a 1400-bed community hospital. All patients admitted to the ICU during a 16-month period, who were expected to require mechanical ventilation for more than 24 hours, were randomized to receive either the ‘classical’ SDD regimen (Group A) or a modified regimen with mupirocin (Group B). Data from 223 patients requiring mechanical ventilation for at least 48 hours, who were neither infected nor receiving antibiotics on ICU admission, was analysed. A 2% paste containing tobramycin, polymyxin E and amphotericin B was applied every 6 hours in the oropharynx to the patients in Group A, while in Group B this formula was modified with the addition of 2% mupirocin. In Group B 0.2 ml of a 2% mupirocin ointment was also applied four times daily in both nostrils. Patients in Group A received a soft paraffin ointment as a placebo indistinguishable from mupirocin. Patients in both groups received the classic SDD regimen through the nasogastric tube. Systemic antibiotic prophylaxis was not used. Data on lower airway infection, and blood infection, infections of intravascular catheters, antibiotic consumption and expenditures for antibiotics were analysed. The diagnosis of ventilator-associated pneumonia (VAP) was based on quantitative cultures of protected specimen brush samples (PSB) or on the results of distal broncho-alveolar lavage (BAL). One hundred and four patients received the ‘classical’ SDD and 119 the modified regimen. Overall 29 patients, 20 in Group A and nine in Group B (p  <  0.02) had a total of 33 cases of pneumonia. There were 23 episodes of pneumonia in Group A and 10 in Group B (p  <  0.02). Gram-positive bacteria were isolated from samples in 17 episodes in Group A and six in Group B (p  <  0.02). Staphylococcus aureus was isolated in nine cases of pneumonia in Group A and once in the ‘mupirocin’ group (p  <  0.05). MRSA were isolated in seven out of nine cases in Group A and in the only case in Group B. There were no differences in the isolation of Gram-negative bacilli. Antibiotic consumption and cost were lower in Group B. In conclusion, our data show that the topical use of a modified formula of SDD, with the addition of mupirocin to the oral paste and in the anterior nares, is associated with a reduction in lung infections caused by gram-positives and in a reduction in antibiotic consumption and in the overall expenditure for antibiotics.