Carriage of methicillin-resistant Staphylococcus aureus is associated with an increased risk of infection after liver transplantation

Methicillin-resistant Staphylococcus aureus infection in liver transplantation: a matched controlled study

The purpose of this study was to evaluate the clinical impact of methicillin-resistant Staphylococcus aureus (MRSA) infections on transplant recipients.

METHODS

Liver and kidney recipients with MRSA infections were retrospectively identified and compared to an age, gender, UNOS status, organ transplanted, and transplant date matched (2:1) non-MRSA-infected recipient control group. All MRSA infections were initially treated with vancomycin, and four (33%) liver recipients were converted to linezolid therapy after failing to improve with vancomycin.

RESULTS

The overall MRSA infection incidence was 1.4% (24/1770) with MRSA more common in liver (3.75%; 12/320) than kidney transplants (0.8%; 12/1450) (P < .001). The most common sites of MRSA infection were blood (42%), lung (38%), and abdomen (29%). The MRSA group had a greater percentage of prior antibiotic usage (79% vs 40%; P < .0015). The MRSA group experienced more posttransplant complications (52% vs 19%; P < .011)), and exhibited a trend toward greater length of stay in the intensive care unit (7.8 vs 4.6 days; P = .09), but not overall length of stay. Survival was similar in MRSA and non-MRSA groups (75% vs 88%; P = .17). No significant differences in mortality were noted between liver and kidney recipients infected with MRSA (P = .6).

CONCLUSION

MRSA infection is associated with a higher incidence of posttransplant complications and antibiotic usage in both liver and kidney recipients compared to patients with MRSA infection.

Influence of methicillin-resistant Staphylococcus aureus carrier status in liver transplant recipients

The prevalence of methicillin-resistant Staphylococus aureus (MRSA) has increased worldwide and MRSA has emerged as an important cause of sepsis in cirrhotic patients and liver transplant recipients. In this retrospective study, the prevalence of MRSA colonization and its influence on infections following orthotopic liver transplantation (OLT) was investigated. From August, 2002 until November, 2004, 66 primary cadaver OLT were performed for adult recipients. Antibody induction used Daclizumab (n = 49) or ATG (n = 14). Maintenance immunosuppression consisted of tacrolimus and steroids, with 30 patients receiving mycophenolate mofetil and 4, rapamune. For perioperative anti-infectious prophylaxis cefotaxime, metronidazole, and tobramycin were administered for 48 hours. The preoperatively performed routine swabs revealed MRSA colonization in 12 of 66 (18.2%) patients. The stage of cirrhosis was equivalent for MRSA(-) patients according to Child score. The mean MELD score was significantly higher for MRSA(+) patients (24.3 versus 18.7, P = .036). More MRSA(+) patients were hospitalized at the time of transplantation (14/54 versus 8/12, P = .018). The incidence of posttransplant infections was not significantly different among the two groups. Within the first year 7 of 66 (10.6%) patients died: 3 of 12 (25%) MRSA(+) and 4 of 54 (7.4%) MRSA(-). The 1-year survival was lower in the MRSA(+) group (74.1% versus 94.1%). In conclusion, this study did not show that an MRSA-positive carrier status implies an increased risk for septic complications following OLT. Mortality was increased for MRSA(+), but failed to show a significant difference. A significantly higher MELD score and pretransplant hospitalization for MRSA(+) patients may contribute to the higher mortality and reflect sicker patients.

Risk factors for Staphylococcus aureus infection in liver transplant recipients

Staphylococcus aureus is the leading cause of bacterial infection in liver transplant recipients. Preoperative nasal carriage of methicillin-resistant S. aureus (MRSA) is associated with a high risk of infection. We conducted a retrospective cohort study in order to identify independent risk factors for early-onset S. aureus infection after liver transplantation. Patients were screened preoperatively for methicillin-susceptible S. aureus (MSSA) and MRSA nasal carriage. Risk factor analysis was performed by univariate analysis followed by stepwise logistic regression. Of the 323 patients included, 63 (19.5%) patients developed S. aureus infection (36 MRSA, 27 MSSA) within 1 month of surgery. Variables significantly associated with infection in the univariate analysis were MRSA and MSSA nasal carriage, alcoholic cirrhosis, absence of hepatocellular carcinoma, decreased prothrombin ratio, and presence of ascites. In the multivariate analysis, MRSA carriage (odds ratio [OR]: 20.9, P < 0.0001), MSSA carriage (OR: 3.4, P = 0.0004), alcoholic cirrhosis (OR: 2.4, P = 0.01) and decreased prothrombin ratio (OR: 1.2, P = 0.01) were independent predictors of infection. Molecular typing showed that the infecting isolate was identical to the isolate from the nose in most patients. In conclusion, preoperative nasal carriage of MRSA and MSSA is an independent risk factor for S. aureus infection in liver transplant recipients. The infection is most often of endogenous origin. Alcoholic cirrhosis and the severity of liver failure are also associated with a high risk of infection.

Colonization with methicillin-resistant Staphylococcus aureus after liver transplantation

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infection after orthotopic liver transplantation (OLT). Colonization with MRSA is associated with a higher risk of infection. Previous studies have shown a high prevalence of MRSA colonization among OLT candidates. However, the risk of colonization with MRSA after OLT is still unclear. The objective of this study was to estimate the incidence and the factors associated with colonization with MRSA after OLT. This was a prospective cohort study including patients submitted to OLT between the years 2000 and 2002. Surveillance cultures of nasal swab specimens were performed within the 1st 72 hours of hospital admission and, subsequently, on weeks 2, 6, 13, and 26. Patients whose baseline cultures revealed nasal carriage of MRSA were excluded. A total of 60 patients were included in the study. The median follow-up was 72 days. A total of 9 patients (15%) became colonized. In multiple logistic regression analyses, the use of a urinary catheter for > or =5 days (P = .006), postoperative bleeding at the surgical site (P = .009), and preoperative use of fluoroquinolones (P = .08) were associated with a higher risk of colonization. Patients without any of these risk factors did not become colonized. In conclusion, nasal carriage of MRSA is frequently acquired after OLT. Periodic postoperative screening for MRSA carriage should be an integral component in programs designed to reduce nosocomial MRSA transmission in these patients. Further studies are needed to set up and validate a predictive model that could allow targeting postoperative screening to high-risk OLT recipients.