1478. The multivariable analysis for the risk of orthopedic MRSA SSIs among MRSA noncarriers
Session: Poster Abstract Session: HAI: Surgical Site Infections
Friday, October 28, 2016
Room: Poster Hall
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen that is often involved in orthopedic surgical site infections (SSIs). Nasal colonization with MRSA is a risk factor for MRSA SSIs. However, few studies have investigated the risk factors for orthopedic MRSA SSIs in MRSA noncarriers. The present study aimed to evaluate the risk of MRSA infection at orthopedic surgical sites in MRSA noncarriers and to investigate appropriate prophylaxis for orthopedic MRSA SSIs.

Methods: We retrospectively reviewed a population of 2,312 patients who had orthopedic clean surgical treatment at our department from 2008 to 2013 (2,213 MRSA noncarriers and 99 MRSA carriers). Active nasal surveillance culture for MRSA was performed for all patients. For MRSA noncarriers, cefazolin-based antimicrobial prophylaxis of SSIs was implemented. As the risk factor for MRSA SSIs among MRSA noncarriers, the following factors were checked and assessed by multivariable analysis; age (>70 years old), American Society of Anesthesiologists (ASA) classification (>2), diabetes mellitus, over weight (Body mass index >25), operative method, blood transfusion during surgery, prolonged (over 48 hours) duration of postoperative antimicrobial.

Results: The incidence of MRSA SSIs in MRSA noncarriers was significantly lower than that in MRSA carriers (0.81%, 18/2213 vs. 3.03%, 3/99; P=0.03). The procedure of malignant musculoskeletal tumor surgery (odds ratio, 7.18; 95% confidence interval, 2.75-18.7; P <0.001) and prolonged antimicrobial prophylaxis over 48 hours (OR, 3.16; 95% CI, 1.04-9.63; P=0.04) are significantly associated with the MRSA SSI risk among MRSA noncarriers.

Conclusion:  These results suggest that malignant musculoskeletal tumor surgery is significantly associated with the MRSA SSI risk and further implementation including vancomycin prophylaxis may be needed. Prolonged antimicrobial prophylaxis over 48 hours may increase the risk of orthopedic MRSA SSIs among MRSA noncarriers and should therefore be avoided.

Hideki Kawamura, MD, PhD1, Koichi Tokuda, MD, PhD, MPH1, Akari Shigemi, MSc2, Hiroyuki Tominaga, MD, PhD3, Satoshi Nagano, MD, PhD3, Takao Setoghchi, MD, PhD4, Setsuro Komiya, MD, PhD3 and Junichiro Nishi, MD, PhD1, (1)Department of Infection Prevention and Control, Division of Medical and Environmental Safety, Kagoshima University Hospital, Kagoshima, Japan, (2)Department of Infection Control and Prevention, Division of Medical and Environmental Safety, Kagoshima University Hospital, Kagoshima, Japan, (3)Department of Orthopaedic Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan, (4)The Near-Future Locomotor Organ Medicine Creation Course (Kusunoki Kai), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan

Disclosures:

H. Kawamura, None

K. Tokuda, None

A. Shigemi, None

H. Tominaga, None

S. Nagano, None

T. Setoghchi, None

S. Komiya, None

J. Nishi, None

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