G. M. Fitzpatrick6, H. Frum1, R. Quilitz2,5, R. L. Sandin7, D. Ruge7, J. L. Greene2,5, J. R. Garrett1, C. C. Moodie1, E. M. Toloza1,3,4 1Moffitt Cancer Center,Thoracic Oncology,Tampa, FL, USA 2Moffitt Cancer Center,Infectious Diseases,Tampa, FL, USA 3University Of South Florida Morsani College Of Medicine,Surgery,Tampa, FL, USA 4University Of South Florida Morsani College Of Medicine,Oncologic Sciences,Tampa, FL, USA 5University Of South Florida Morsani College Of Medicine,Medicine,Tampa, FL, USA 6University Of South Florida,Morsani College Of Medicine,Tampa, FL, USA 7Moffitt Cancer Center,Pathology,Tampa, FL, USA
Objective: To study the efficacy of preoperative (preop) screening for methicillin-resistant Staphylococcus aureus (MRSA) and of decolonization of MRSA-positive (MRSA-POS) patients (pts) by a trimodality antibiotic regimen aimed at reducing postoperative (postop) MRSA infections.
Methods: At preop clinic evaluation, pts scheduled for thoracic surgery were screened for MRSA via polymerase chain reaction (PCR) of nasal swab specimens. Preop MRSA-POS pts were given oral doxycycline 100 mg twice daily, mupirocin 2% ointment to both nares, and chlorhexidine showers for 5 days for MRSA-decolonization preop, with doxycycline continued 7 more days postop. Pts who were admitted to intensive care had a second MRSA screen immediately postop. We retrospective analyzed 1106 consecutive thoracic surgery pts to determine prevalence of preop MRSA colonization, rates of POS-to-negative(NEG) and NEG-to-POS conversion between preop and immediate postop MRSA screens, and rates of postop MRSA and non-MRSA infections in MRSA-POS and in MRSA-NEG pts. MRSA screens within 60 days prior to surgery and infections within 30 days after surgery were included. Fisher Exact Probability Test was used, with significance at p<0.05.
Results: Of 960 pts who had preop MRSA screen, 4.0% (38/960) were MRSA-POS. Of these MRSA-POS pts, 15.8% (6/38) developed postop infections, compared to 18.8% (173/922) of MRSA-NEG pts (p=0.68). The most common postop infection in each group was an uncomplicated urinary tract infection (UTI). Excluding UTIs, 7.9% (3/38) of MRSA-POS pts and 11.8% (109/922) of MRSA-NEG pts had postop infections, respectively (p=0.61). The only postop MRSA infection in this study was a case of MRSA pneumonia diagnosed on postop day 16 in a pt who was MRSA-NEG preop. Of 530 pts who had both preop and postop MRSA screens, 95.1% (511/530) were MRSA-NEG preop, of which 1.4% (7/511) converted to being MRSA-POS on immediate postop screen. Of the remaining 19/530 pts (3.6%) who were MRSA-POS preop, 68.4% (13/19) converted to being MRSA-NEG on immediate postop screen. Of 15 MRSA-POS pts receiving the complete decolonization antibiotic regimen, 73.3% (11/15) converted to being MRSA-NEG on immediate postop screen, while of the 4 MRSA-POS pts who did not complete the decolonization antibiotic regimen, 50% (2/4) converted to being MRSA-NEG on immediate postop screen (p=0.56).
Conclusions: Prevalence of MRSA colonization in thoracic surgery pts who were screened by PCR of preop nasal swab specimens is similar to those previously published. Rates of conversion from preop MRSA-POS to immediate postop MRSA-NEG indicate overall efficacy of our trimodality decolonization regimen. With adequate decolonization via trimodality treatment, risk of postop MRSA infections or even for non-MRSA infections is not increased in pts screened preop as MRSA-POS versus those screened as MRSA-NEG.