| Healthcare-Associated Infections |
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Healthcare-Associated Infections Peter Linden, MD Professor, Department of Critical Care Medicine, Associate Professor, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania Healthcare-associated infections occur in patients who have experienced recent or even distant exposures to the healthcare environment. These patients may have undergone antibiotic treatment or the placement of intravascular devices, or they may have transferred from other healthcare settings, such as dialysis clinics or long-term care facilities. As a consequence of both recent antibiotic administration and exposure to healthcare workers and healthcare inanimate environments where antimicrobial resistant strains are more common, these individuals often harbor drug-resistant organisms. The early recognition of patients with healthcare-associated infections can significantly improve patient outcome. Recognizing drug-resistant healthcare-associated infections influences the administration of a range of medical procedures, including the selection of antimicrobial treatments, the approach to diagnosis, and the implementation of infection control measures. In patients with resistant infections, such as methicillin-resistant Staphylococcus aureus (MRSA), an increasing delay between presentation and the initiation of appropriate antibiotic has been shown to significantly increase the risk of mortality.1 Being right early, rather than 2 to 3 days after the initial presentation, is an important determinant of patient survival. For some infections, definitions of healthcare-associated infections are well established. These include pneumonia or other infections of the respiratory tract. Definitions of healthcare-associated infections are less well defined in other clinical settings. For example, complicated skin and skin structure infection (CSSSI) has traditionally been categorized as community-acquired versus hospital-acquired, but there is no specific, generally accepted definition for healthcare-associated CSSSI. However, the recognition of healthcare-associated CSSSI as a discrete entity may be increasing as drug-resistant organisms are becoming more common among these patients. In recent clinical trials that examined various antimicrobial treatment regimens, MRSA was identified in approximately 10% to 50% of patients.2-6 Healthcare-associated infection has also not been well defined in the setting of intraabdominal infections which has a diverse spectrum of pathology, including any type of visceral abscess (eg, appendicitis, cholangitis, and hepatic abscess), or intraabdominal spillage resulting in an intraperitoneal abscess or frank peritonitis. These are usually categorized as complicated or uncomplicated. However, it is clear that hospital length of stay and antibiotic exposure can significantly modify the microorganisms present. The core microflora are likely to include antibiotic-susceptible enteric gram-negative species, including Escherichia coli, Klebsiella, vancomycin-sensitive Enterococcus, and anaerobes in formed abscesses and infection arising from the distal gastrointestinal tract. After hospitalization and antibiotic exposure, abdominal flora are more likely to consist of multiresistant gram-negative bacteria, including extended-spectrum β-lactamase E coli, Klebsiella and Enterobacter spp, vancomycin-resistant Enterococcus, and Candida. In addition, the risk of mortality associated with postoperative peritonitis is significantly increased among patients with drug-resistant organisms and inadequate antimicrobial therapy.7 Findings such as these underscore the need for clinicians to be aware of healthcare-associated infections as a risk factor in order to increase the likelihood of a correct initial selection of antibiotics. References 1. Schramm GE, Johnson JA, Doherty JA, et al. Methicillin-resistant Staphylococcus aureus sterile-site infection: the importance of appropriate initial antimicrobial treatment. Crit Care Med. 2006;34:2069-2074. 2. Arbeit RD, Maki D, Tally FP, et al. The safety and efficacy of daptomycin for the treatment of complicated skin and skin-structure infections. Clin Infect Dis. 2004;38:1673-1681. 3. Jauregui LE, Babazadeh S, Seltzer E, et al. Randomized, double-blind comparison of once-weekly dalbavancin versus twice-daily linezolid therapy for the treatment of complicated skin and skin structure infections. Clin Infect Dis. 2005;41:1407-1415. 4. Stryjewski ME, Graham DR, Wilson SE, et al. Telavancin versus vancomycin for the treatment of complicated skin and skin-structure infections caused by gram-positive organisms. Clin Infect Dis. 2008;46:1683-1693. 5. Breedt J, Teras J, Gardovskis J, et al. Safety and efficacy of tigecycline in treatment of skin and skin structure infections: results of a double-blind phase 3 comparison study with vancomycin-aztreonam. Antimicrob Agents Chemother. 2005;49:4658-4666. 6. Noel GJ, Strauss RS, Amsler K, et al. Results of a double-blind, randomized trial of ceftobiprole treatment of complicated skin and skin structure infections caused by gram-positive bacteria. Antimicrob Agents Chemother. 2008;52:37-44. 7. Montravers P, Gauzit R, Muller C, et al. Emergence of antibiotic-resistant bacteria in cases of peritonitis after intraabdominal surgery affects the efficacy of empirical antimicrobial therapy. Clin Infect Dis. 1996;23:486-494.
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