Staphylococcus Aureus Prevention Strategies in Cardiac Surgery: A Cost-Effectiveness Analysis.

BACKGROUND: Cardiac surgery patients colonized with Staphylococcus aureus have a greater risk of surgical site infection (SSI). The purpose of this study was to evaluate the cost-effectiveness of decolonization strategies to prevent SSIs. METHODS: We compared three decolonization strategies: universal decolonization (UD), all subjects treated; targeted decolonization (TD), only S aureus carriers treated; and no decolonization (ND). Decolonization included mupirocin, chlorhexidine, and vancomycin. We implemented a decision tree comparing the costs and quality-adjusted life-years (QALYs) of these strategies on SSI over a 1-year period for subjects undergoing coronary artery bypass graft surgery from a US health sector perspective. Deterministic and probabilistic sensitivity analyses were conducted to address the uncertainty in the variables. RESULTS: Universal decolonization was the dominant strategy because it resulted in reduced costs at near-equal QALYs compared with TD and ND. Compared with ND, UD decreased costs by $462 and increased QALYs by 0.002 per subject, whereas TD decreased costs by $205 and increased QALYs by 0.001 per subject. For 1,000 subjects, UD prevented 19 SSI and TD prevented 10 SSI compared with ND. Sensitivity analysis showed UD to be the most cost-effective strategy in more than 91% of simulations. For the 220,000 coronary artery bypass graft procedures performed yearly in the United States, UD would save $102 million whereas TD would save $45 million compared with ND. CONCLUSIONS: Universal decolonization outperforms other strategies. However, the potential costs savings of $57 million per 220,000 coronary artery bypass graft procedures comparing UD versus TD must be weighed against the potential risk of developing resistance associated with universal decolonization.

Preoperative Staphylococcus Aureus Screening and Targeted Decolonization in Cardiac Surgery.

BACKGROUND: We assessed the impact of preoperative Staphylococcus aureus screening and targeted decolonization on the incidence of postoperative methicillin-resistant S aureus (MRSA) colonization, intensive care unit MRSA transmission, and surgical site infections in cardiac surgery patients. METHODS: We reviewed medical records for all adult patients during two periods: preintervention (January 2007 to April 2010) and intervention (January 2011 to December 2014). In the intervention period, we performed nasal screening for methicillin-sensitive S aureus and MRSA using polymerase chain reaction within 30 days of the operation. Colonized patients received intranasal mupirocin twice daily and chlorhexidine baths daily for 5 days; patients colonized with MRSA also received prophylactic vancomycin plus cefazolin with contact isolation precautions. Nasal surveillance for MRSA was performed on intensive care unit admission and weekly thereafter. Multivariable logistic regression models were constructed to determine risk factors for postoperative MRSA colonization, and surgical site infections and the impact of our screening program was assessed in these models. Poisson regression was used to assess MRSA transmission. RESULTS: Comparing 2,826 preintervention and 4,038 intervention patients, cases differed in age, diabetes mellitus, preoperative infection, preoperative length of stay, and bypass time (all p ≤ 0.03). Intervention patients had risk-adjusted reductions in MRSA colonization (odds ratio 0.53, 95% confidence interval [CI]: 0.37 to 0.76, p < 0.001), transmission (incidence rate ratio 0.29, 95% CI: 0.13 to 0.65, p = 0.002), and surgical site infections (odds ratio 0.58, 95% CI: 0.40 to 0.86, p = 0.007). Increased duration of preoperative decolonization therapy was associated with decreased postoperative MRSA colonization (odds ratio 0.73, 95% CI: 0.53 to 1.00, p = 0.05). CONCLUSIONS: Preoperative S aureus screening with targeted decolonization was associated with reduced MRSA colonization, transmission, and surgical site infections. Duration of preoperative therapy correlated with decreased frequency of postoperative MRSA colonization.

Perivascular fibrosis in the bone marrow in sickle cell disease.

CONTEXT: Magnetic resonance imaging of bone marrow in homozygous sickle cell disease (hemoglobin [Hb] SS) shows nonhomogeneous, mottled signals that increase with age and number of crises. The pattern of these signals is reminiscent of the underlying vascular architecture, but histopathology of this tissue has not been adequately studied. OBJECTIVE: To elucidate the histopathology of blood vessels in the bone marrow in sickle cell disease. DESIGN: Retrospective histochemical morphometric study of bone marrow arteries by point counting in HbSS (13 cases) and sickle cell Hb C (HbSC) (8 cases) compared to nonanemic normal controls (HbAA) (10 cases). All patients were nondiabetic, normotensive, younger than 37 years, and matched for age group. RESULTS: The mean point count for perivascular fibrous tissue was significantly greater in the HbSS group (P <.001) in both small (P <.001) and medium-sized (P =.002) vessels, and in both age groups (pediatric, P <.001; adult, P =.005) compared with the HbAA group. Additional analysis showed the difference was significant in HbSS pediatric small vessels (P <.001) and in pediatric and adult medium vessels (P =.045 and P =.03, respectively). Ratios of fibrous tissue to muscle showed proportionately greater fibrous tissue in HbSS pediatric small (P <.001) and medium-sized vessels (P =.02), and in adult large vessels (P =.03). Mean point counts for muscle were significantly decreased in HbSS small vessels when all ages were compared as a group (P =.02), but when compared by age groups, counts were significantly increased in adult HbSS medium-sized vessels (P =.01). Overall mean point counts for muscle and fibrous tissue in the HbSC group were intermediate between those of the HbSS and HbAA groups, but were not significantly different from counts in the HbAA group (P =.78 and P =.35, respectively). CONCLUSION: In sickle cell disease, arterial vessels in the bone marrow show significantly increased fibrous connective tissue and changes in muscle that vary with age and vessel size.