Pseudomonas aeruginosa is one of the leading gram-negative organisms associated with nosocomial infections. The increasing frequency of multi-drug-resistant Pseudomonas aeruginosa (MDRPA) strains is concerning as efficacious antimicrobial options are severely limited. By searching MEDLINE from January 1966-February 2005 and relevant journals for abstracts, we reviewed the frequency, risk factors, and patient outcomes of MDRPA nosocomial infections in critically ill patients, determined the available antimicrobial therapies, and then provided recommendations for clinicians. The definition of MDRPA was established as isolates intermediate or resistant to at least three drugs in the following classes: beta-lactams, carbapenems, aminoglycosides, and fluoroquinolones. Reported rates of MDRPA varied from 0.6-32% according to geographic location and type of surveillance study. Risk factors for MDRPA infection included prolonged hospitalization, exposure to antimicrobial therapy, and immunocompromised states such as human immunodeficiency virus infection. Emergence of MDRPA isolates during therapy was reported in 27-72% of patients with initially susceptible P. aeruginosa isolates. Patients with severe MDRPA infections should be treated with combination therapy, consisting of an antipseudomonal beta-lactam with an aminoglycoside or fluoroquinolone rather than aminoglycoside and fluoroquinolone combinations, to provide adequate therapy and improve patient outcomes. Synergy has been observed when resistant antipseudomonal drugs were combined in vitro against MDRPA with successful clinical application reported in two centers. Colistin with adjunctive therapy, such as a beta-lactam or rifampin, may be a useful agent in MDRPA when antimicrobial options are limited, but patients should be monitored closely for toxicities associated with this agent. Standardization of terminology for MDRPA isolates is needed for consistency and comparability of surveillance and institutional reports. Clinical studies are needed to identify risk factors for MDRPA development and to determine the economic impact of these infections, as well as to determine the most efficacious antimicrobial regimens and duration of therapy to maximize outcomes in the treatment of MDRPA infections.

Nosocomial infections caused by Pseudomonas aeruginosa in critically ill patients are often difficult to treat due to resistance to multiple antimicrobials. The purpose of this study was to evaluate antimicrobial resistance among P. aeruginosa isolates from intensive care unit patients in the United States from 1993 to 2002 by using the Intensive Care Unit Surveillance Study database. Over the 10-year period, susceptibility of 13,999 nonduplicate isolates of P. aeruginosa was analyzed. From 1993 to 2002, nationwide increases in antimicrobial resistance were greatest for ciprofloxacin, imipenem, tobramycin, and aztreonam. Rates of multidrug resistance (resistance to >3 of the following drugs: ceftazidime, ciprofloxacin, tobramycin, and imipenem) increased from 4% in 1993 to 14% in 2002. The lowest dual resistance rates were observed between aminoglycosides or fluoroquinolones with piperacillin-tazobactam while the highest were for those that included ␤-lactams and ciprofloxacin. Ongoing surveillance studies are crucial in monitoring antimicrobial susceptibility patterns and selecting empirical treatment regimens.Pseudomonas aeruginosa is one of the most common gramnegative pathogens associated with nosocomial infections (11). Unfortunately, resistance to available antipseudomonal agents is on the rise, jeopardizing selection of appropriate treatment and subsequently increasing morbidity and mortality in patients infected with this pathogen (1, 9). In fact, inadequate empirical therapy has been associated with mortality exceeding 30% (6), and delays in the initiation of appropriate therapy contribute to increased length of hospital stay and persistence of infection (8).The selection of appropriate antimicrobial therapy requires active surveillance of emerging resistance trends and continuing education among the health care providers and institution(s) involved. The objectives of this study were to analyze data from the Intensive Care Unit Surveillance Study (ISS) to assess the rates of resistance and multidrug resistance among P. aeruginosa isolates in intensive care units (ICUs) in the United States from 1993 to 2002 and to use these data to evaluate current recommendations for empirical antibiotic regimens.(These data were presented as a poster presentation at the 43rd Annual Interscience Conference on Antimicrobial Agents and Chemotherapy on 17 September 2003.) MATERIALS AND METHODSThe ISS is a national postmarketing surveillance program sponsored by Merck and Company Inc. (Rahway, N.J.) since 1989. Participating institutions submitted susceptibility data for approximately 100 to 200 consecutive gram-negative aerobic isolates from ICU patients annually. All organisms were identified to the species level and susceptibility testing was conducted at each institution using a standardized custom microdilution MIC panel (Microscan MKD MIC; Dade International MicroScan, Sacramento, Calif.) (10). The P. aeruginosa quality control strain ATCC 27853 was used weekly in each laboratory.In this study, independent of the res...

IMPORTANCE Histamine-2 receptor antagonists (H 2 RAs) and proton pump inhibitors (PPIs) are commonly used to prevent gastrointestinal tract (GI) hemorrhage in critically ill patients. The stronger acid suppression of PPIs may reduce the rate of bleeding but enhance infectious complications, specifically pneumonia and Clostridium difficile infection (CDI). OBJECTIVE To evaluate the occurrence and risk factors for GI hemorrhage, pneumonia, and CDI in critically ill patients. DESIGN, SETTING, AND PARTICIPANTS A pharmacoepidemiological cohort study was conducted of adult patients requiring mechanical ventilation for 24 hours or more and administered either an H 2 RA or PPI for 48 hours or more while intubated across 71 hospitals between January 1, 2003, and December 31, 2008. Propensity score-adjusted and propensity-matched multivariate regression models were used to control for confounders. MAIN OUTCOMES AND MEASURES Primary outcomes were secondary diagnoses of International Classification of Diseases, Ninth Revision (ICD-9)-coded GI hemorrhage, pneumonia, and CDI occurring 48 hours or more after initiating invasive ventilation. RESULTS Of 35 312 patients, 13 439 (38.1%) received H 2 RAs and 21 873 (61.9%) received PPIs. Gastrointestinal hemorrhage (2.1% vs 5.9%; P < .001), pneumonia (27% vs 38.6%; P < .001), and CDI (2.2% vs 3.8%; P < .001) occurred less frequently in the H 2 RA group. After adjusting for propensity score and covariates, odds ratios of GI hemorrhage (2.24; 95% CI, 1.81-2.76), pneumonia (1.2; 95% CI, 1.03-1.41), and CDI (1.29; 95% CI, 1.04-1.64) were greater with PPIs. Similar results were obtained in the propensity-matched models of 8799 patients in each cohort. CONCLUSIONS AND RELEVANCE Proton pump inhibitors are associated with greater risks of GI hemorrhage, pneumonia, and CDI than H 2 RAs in mechanically ventilated patients. Numerous other risk factors are apparent. These data warrant confirmation in comparative prospective studies.

Extravasations are common manifestations of iatrogenic injury that occur in patients requiring intravenous delivery of known vesicants. These injuries can contribute substantially to patient morbidity, cost of therapy, and length of stay. Many different mechanisms are behind the tissue damage during extravasation injuries. In general, extravasations consist of four different subtypes of tissue injury: vasoconstriction, osmotic, pH related, and cytotoxic. Recognition of high-risk patients, appropriate cannulation technique, and monitoring of higher risk materials remain the standard of care for the prevention of extravasation injury. Prompt interdisciplinary action is often necessary for the treatment of extravasation injuries. Knowledge of the mechanism of extravasation-induced tissue injury, agents for reversal, and appropriate nonpharmacologic treatment methods is essential. The best therapeutic agent for treatment of vasopressor extravasation is intradermal phentolamine. Topical vasodilators and intradermal terbutaline may provide relief. Intradermal hyaluronidase has been effective for hyperosmotic extravasations, although its use largely depends on the risk of tissue injury and the severity of extravasation. Among the hyperosmotic agents, calcium extravasation is distinctive because it may present as an acute tissue injury or may possess delayed clinical manifestations. Extravasation of acidic or basic materials can produce significant tissue damage. Phenytoin is the prototypical basic drug that causes a clinical manifestation known as purple glove syndrome (PGS). This syndrome is largely managed through preventive and conservative treatment measures. Promethazine is acidic and can cause a devastating extravasation, particularly if administered inadvertently through the arteriolar route. Systemic heparin therapy remains the accepted treatment option for intraarteriolar administration of promethazine. Overall, the evidence for managing extravasations due to noncytotoxic medications is nonexistent or limited to case reports. More research is needed to improve knowledge of patient risk, prompt recognition of the extravasation, and time course for tissue injury, and to develop prevention and treatment strategies for extravasation injuries.

The involvement of clinical pharmacists in the care of critically ill Medicare patients with infections is associated with improved clinical and economic outcomes. Hospitals should consider employing clinical ICU pharmacists.