Patients who acquire SSTIs in healthcare settings may stay longer in hospitals to control the infection

Oct 31 2009

Patients who acquire skin and soft tissue infections (SSTIs) in a hospital or other healthcare setting may be more likely to receive inappropriate antibiotic therapy at the beginning of their treatment. As a result, they also may have significantly longer hospital stays to control the infection. Preliminary results from a new study by the Henry Ford Health System evaluated records from patients who acquired SSTIs in hospital and healthcare settings and those who acquired similar infections in the community. Results from the study, which were presented today at the 47th Annual Meeting of the Infectious Diseases Society of America (IDSA), also shed new light on baseline risk factors that are associated with inappropriate initial therapy (Abstract #053). This information may help guide clinicians in the appropriate treatment of SSTIs.

Complicated skin and skin structure infections (cSSTIs) account for almost 10 percent of all hospital admissions in the U.S.(1) According to the Centers for Disease Control and Prevention (CDC), approximately 25-30% of the U.S. population has some form of Staphylococcus aureus on their skin, and an increasing number of those individuals carry the more resistant form known as methicillin-resistant Staphylococcus aureus (MRSA).(2)(3)(4)

"Up to this point, the importance of initiating appropriate empiric therapy has been well documented in other infections such as pneumonia, but not in skin infections," said study author Marcus Zervos, M.D. Division Head, Infectious Diseases, Director Infection Control at the Henry Ford Health System, in Detroit, MI. "These results show that a more comprehensive evaluation of hospital patient risk factors may help physicians determine the optimal initial antibiotic treatment, sparing patients unnecessary treatment and time in the hospital."

Risk Factors for Inappropriate Treatment

In the hospitalized patient population, three risk factors were identified as being associated with receiving inappropriate antibiotic treatment:

• Healthcare-associated infection status (i.e., recent exposure within nursing homes, or medical clinics)
• Presence of a "gram-negative" pathogen
• Presence of a pathogen other than a Streptococcus species

Study Methods and Key Results

The study, conducted by the Henry Ford Health System with a grant from Ortho-McNeil Janssen Scientific Affairs, LLC, is an analysis of administrative and medical records of 368 patients hospitalized between late 2005 and 2008 with an admission diagnosis of a cSSTI. Patients were classified as having healthcare associated infections (HCAI) if they were: 1) recently hospitalized; 2) immunocompromised; 3) on hemodialysis; or 4) admitted from nursing home. All others were classified as having community-acquired infections (CAI). Initial empiric therapy (IET) was considered appropriate if antibiotics active against the infecting pathogen(s) were administered within 24 hours of admission.

Among patients with SSTIs whose infection was confirmed by culture ("culture-positive"), those who acquired an infection in a hospital or healthcare setting were more likely to be treated inappropriately than those who acquired an infection in a community setting (35.2% vs. 20.5%, p<0.01). Additionally, when other risk factors were adjusted, patients who received inappropriate initial therapy stayed in the hospital an average of nearly six days longer than patients who received appropriate initial therapy.

Moreover, the study showed that S. aureus was the most common pathogen in patients with both HCAI (55.6%) as well as CAI (58.2%), and the majority of these were methicillin-resistant S. aureus, commonly referred to as MRSA (73.4% in HCAI and 64.8% in CAI). MRSA represents a growing healthcare concern and has become an increasingly common cause of SSTIs, as evidenced by the prevalence of MRSA in this study.