Physician's Weekly Article - Hospital-Acquired Pneumonia: A Status Update

       In 2005, new guidelines were released to manage and prevent hospital-acquired pneumonia. Is progress being made in the battle against the infection?

      Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection in ICU patients in the United States and is associated with high morbidity and costs. Studies have shown that the presence of HAP increases hospital lengths of stay by an average of 7 to 9 days per patient, producing an excess cost of more than $40,000 per patient. “Considering the profound incidence, morbidity, and mortality associated with HAP, this is one of the most important hospital-acquired infections, particularly for ICU patients,” says Michael S. Niederman, MD. “Compounding the problem is that there are several types of HAP, including ventilator-acquired pneumonia (VAP) and health-care–associated pneumonia (HCAP). Patients with HCAP can bring multi-drug resistant (MDR) pathogens with them when they arrive to the hospital.”

      In 2005, the American Thoracic Society (ATS) and the Infectious Disease Society of America (IDSA) published guidelines for the treatment of HAP, with special sections on VAP, HCAP, and nosocomial pneumonia in non-ventilated patients. The guidelines emphasized several therapeutic principles, including the need to use adequate initial antibiotic therapy for these infections (Table 1). “The guidelines highlight the importance of using an appropriate antibiotic to which the organism is sensitive,” Dr. Niederman says. “They also recommend using an antibiotic that penetrates the site of infection and one that’s used in the correct doses.”

      Resistance Issues Persist

      Since the publication of the 2005 ATS/IDSA guidelines, research has shown that MDR bacteria are becoming even more common causes of HAP. Of particular importance are Pseudomonas aeruginosa, Acinetobacter species, and Staphylococcus aureus. “These organisms are frequently antibiotic resistant,” Dr. Niederman notes, “and this resistance is not always anticipated by the treating physician. These same organisms are commonly treated with inappropriate empiric therapy, thereby adding to the mortality rates associated with HAP. If the wrong initial empiric therapy is chosen, the outcomes are not as good as when the most appropriate therapy is selected.”

      The 2005 ATS/IDSA guidelines for HAP focus on several key principles when treating the infection (Figure 1). “Prompt empiric antibiotic therapy, use of clinical and microbiologic data to narrow and focus therapy (when possible), and short durations of therapy are recommended for many patients,” says Dr. Niederman. “The key is to choose the right drug at the right dose for maximum efficacy. At the same time, a strong emphasis must be placed on de-escalation of antibiotics. After clinical and microbiologic data are returned, it’s critical to narrow the focus of therapies so that broad treatments are not used excessively for long periods of time.”

      Assessing Guideline Implementation

      Although outcomes data on the implementation of HAP guidelines in hospitals are scarce, Dr. Niederman says that many institutions are making strides toward improving their protocols. “Hospitals are increasingly becoming more aware of the importance of having a local antibiogram, which provides results of laboratory testing for the sensitivity of the commonly encountered bacteria to different antibiotics,” he says. “We’ve learned that tailoring empiric therapy for each patient can have a dramatic impact on outcomes. Hospitals are also gaining a greater understanding of the complexities of bacteriology and the need for initial broad-spectrum therapy to increase the likelihood of initially accurate and appropriate antibiotic therapy. As a result, many hospitals are developing better protocols for treating HAP. Furthermore, strategies for de-escalation and shorter durations of therapy within hospital protocols are becoming more common. The net result is that many of the guideline principles are being incorporated into practice.”

      Emerging Therapeutic Options

      According to Dr. Niederman, there remains a significant need for new drugs with activity against the organisms that are frequently antibiotic resistant. “For example, linezolid has emerged as a drug that targets methicillan-resistant Staphylococcus aureus (MRSA), and early studies suggest that telavancin may become an effective agent for this organism in the future. Tigecycline appears to have activity against Acinetobacter, but investigations on this agent have yet to determine the most appropriate dosing for critically ill and ventilated patients. Doripenem appears to be more active in vitro than other available carbapenems to treat Pseudomonas aeruginosa. Another agent being assessed is ceftobiprole, which may have the potential to treat both Pseudomonas aeruginosa and MRSA. The hope is that clinical trials will demonstrate that these agents can be added to the armamentarium of available drugs to improve outcomes in HAP.”

      Michael S. Niederman, MD, has disclosed to Physician’s Weekly that he has served as a consultant for Pfizer, Ortho-McNeil, Merck, Theravance, Wyeth, AstraZeneca, and Schering Plough. He has also worked as a paid speaker for Pfizer, Merck, and Schering Plough.