Alex Hoban

Validation of a clinical score for assessing the risk of resistant pathogens in patients with pneumonia presenting to the emergency department.

BACKGROUND Resistant organisms (ROs) are increasingly implicated in pneumonia in patients presenting to the emergency department (ED). The concept of healthcare-associated pneumonia (HCAP) exists to help identify patients infected with ROs but may be overly broad. We sought to validate a previously developed score for determining the risk for an RO and to compare it with the HCAP definition. METHODS We evaluated adult patients admitted via the ED with bacterial pneumonia (January-December 2010). We defined methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and extended-spectrum β-lactamases as ROs. The risk score was as follows: 4, recent hospitalization; 3, nursing home; 2, chronic hemodialysis; 1, critically ill. We evaluated the screening value of the score and of HCAP by determining their areas under the receiver-operating characteristic (AUROC) curves for predicting ROs. RESULTS The cohort included 977 patients, and ROs were isolated in 46.7%. The most common organisms included MRSA (22.7%), P. aeruginosa (19.1%), and Streptococcus pneumoniae (19.1%). The risk score was higher in those with an RO (median score, 4 vs 1; P < .001). The AUROC for HCAP equaled 0.62 (95% confidence interval [CI], .58-.65) versus 0.71 (95% CI, .66-.73) for the risk score. As a screening test for ROs, a score > 0 had a high negative predictive value (84.5%) and could lead to fewer patients unnecessarily receiving broad-spectrum antibiotics. CONCLUSIONS ROs are common in patients presenting to the ED with pneumonia. A simple clinical risk score performs moderately well at classifying patients regarding their risk for an RO.

The determinants of hospital mortality among patients with septic shock receiving appropriate initial antibiotic treatment

Objective:To identify the determinants of hospital mortality among patients with septic shock receiving appropriate initial antibiotic treatment. Design:A retrospective cohort study of hospitalized patients with blood culture positive septic shock (January 2002–December 2007). Setting:Barnes-Jewish Hospital, a 1,250-bed urban teaching hospital. Patients:Four hundred thirty-six consecutive patients with septic shock and a positive blood culture. Interventions:Data abstraction from computerized medical records. Measurements and Main Results:Septic shock was associated with bloodstream infection due to Gram-negative bacteria (59.2%) and Gram-positive bacteria (40.8%). Two hundred twenty-four patients (51.4%) died during their hospitalization. The presence of infection attributed to antibiotic-resistant bacteria was similar for patients who survived and expired (22.6% vs. 20.1%; p = .516). Multivariate logistic regression analysis demonstrated that infection acquired in the intensive care unit (adjusted odds ratio 1.99; 95% confidence interval 1.52–2.60; p = .011) and increasing Acute Physiology and Chronic Health Evaluation II scores (one-point increments) (adjusted odds ratio 1.11; 95% confidence interval 1.09–1.14; p < .001) were independently associated with a greater risk of hospital mortality, whereas infection with methicillin-susceptible Staphylococcus aureus (adjusted odds ratio 0.32; 95% confidence interval 0.20–0.52; p = .017) was independently associated with a lower risk of hospital mortality. Patients infected with methicillin-susceptible Staphylococcus aureus infections were statistically younger and had lower Charlson comorbidity and Acute Physiology and Chronic Health Evaluation II scores compared to patients with non-methicillin-susceptible Staphylococcus aureus infections. Conclusions:Among patients with septic shock who receive appropriate initial antibiotic treatment, acquisition of infection in the intensive care unit and severity of illness appear to be the most important determinants of clinical outcome.

Epidemiology and outcomes of hospitalizations with complicated skin and skin-structure infections: implications of healthcare-associated infection risk factors.

OBJECTIVE Healthcare-associated infections are likely to be caused by drug-resistant and possibly mixed organisms and to be treated with inappropriate antibiotics. Because prompt appropriate treatment is associated with better outcomes, we studied the epidemiology of healthcare-associated complicated skin and skin-structure infections (cSSSIs). PATIENTS Persons hospitalized with cSSSI and a positive culture result. METHODS We conducted a single-center retrospective cohort study from April 2006 through December 2007. We differentiated healthcare-associated from community-acquired cSSSIs by at least 1 of the following risk factors: (1) recent hospitalization, (2) recent antibiotics, (3) hemodialysis, and (4) transfer from a nursing home. Inappropriate treatment was defined as no antimicrobial therapy with activity against the offending pathogen(s) within 24 hours after collection of a culture specimen. Mixed infections were those caused by both a gram-positive and a gram-negative organism. RESULTS Among 717 hospitalized patients with cSSSI, 527 (73.5%) had healthcare-associated cSSSI. Gram-negative organisms were more common (relative risk, 1.24 [95% confidence interval, 1.14-1.35) and inappropriate treatment trended toward being more common (odds ratio, 1.29 [95% confidence interval, 0.85-1.95]) in healthcare-associated cSSSI than in community-acquired cSSSI. Mixed cSSSIs occurred in 10.6% of patients with healthcare-associated cSSSI and 6.3% of those with community-acquired cSSSI (P = .082) and were more likely to be treated inappropriately than to be nonmixed infections (odds ratio, 2.42 [95% confidence interval, 1.43-4.10]). Both median length of hospital stay (6.2 vs 2.9 days; P < .001) and mortality rate (6.6% vs 1.1%; P = .003) were significantly higher for healthcare-associated cSSSI than community-acquired cSSSI. CONCLUSIONS Healthcare-associated cSSSIs are common and are likely to be caused by gram-negative organisms. Mixed infections carry a >2-fold greater risk of inappropriate treatment. Healthcare-associated cSSSIs are associated with increased mortality and prolonged length of hospital stay, compared with community-acquired cSSSIs.

Clostridium difficile infection: a multicenter study of epidemiology and outcomes in mechanically ventilated patients.

Objectives:Clostridium difficile is a leading cause of hospital-associated infection in the United States. The purpose of this study is to assess the prevalence of C. difficile infection among mechanically ventilated patients within the ICUs of three academic hospitals and secondarily describe the influence of C. difficile infection on the outcomes of these patients. Design:A retrospective cohort study. Setting:ICUs at three teaching hospitals: Barnes-Jewish Hospital, Mayo Clinic, and Creighton University Medical Center over a 2-year period. Patients:All hospitalized patients requiring mechanical ventilation for greater than 48 hours within an ICU were eligible for inclusion. Interventions:None. Measurements and Main Results:A total of 5,852 consecutive patients admitted to the ICU were included. Three hundred eighty-six (6.6%) patients with development of C. difficile infection while in the hospital (5.39 cases/1,000 patient days). Septic shock complicating C. difficile infection occurred in 34.7% of patients. Compared with patients without C. difficile infection (n = 5,466), patients with C. difficile infection had a similar hospital mortality rate (25.1% vs 26.3%, p = 0.638). Patients with C. difficile infection were significantly more likely to be discharged to a skilled nursing or rehabilitation facility (42.4% vs 31.9%, p < 0.001), and the median hospital (23 d vs 15 d, p < 0.001) and ICU length of stay (12 d vs 8 d, p < 0.001) were found to be significantly longer in patients with C. difficile infection. Conclusions:Clostridium difficile infection is a relatively common nosocomial infection in mechanically ventilated patients and is associated with prolonged length of hospital and ICU stay, and increased need for skilled nursing care or rehabilitation following hospital discharge.

Prolonged Infusion Antibiotics for Suspected Gram-Negative Infections in the ICU: A Before-After Study

BACKGROUND: β-Lactam antibiotics demonstrate time-dependent killing. Prolonged infusion of these agents is commonly performed to optimize the time the unbound concentration of an antibiotic remains greater than the minimum inhibitory concentration and decrease costs, despite limited evidence suggesting improved clinical results. OBJECTIVE: To determine whether prolonged infusion of β-lactam antibiotics improves outcomes in critically ill patients with suspected gram-negative infection. METHODS: We conducted a single-center, before-after, comparative effectiveness trial between January 2010 and January 2011 in the intensive care units at Barnes-Jewish Hospital, an urban teaching hospital affiliated with the Washington University School of Medicine in St. Louis, MO. Outcomes were compared between patients who received standardized dosing of meropenem, piperacillin-tazobactam, or cefepime as an intermittent infusion over 30 minutes (January 1, 2010, to June 30, 2010) and patients who received prolonged infusion over 3 hours (August 1, 2010, to January 31, 2011). RESULTS: A total of 503 patients (intermittent infusion, n = 242; prolonged infusion, n = 261) treated for gram-negative infection were included in the clinically evaluable population. Approximately 50% of patients in each group received cefepime and 20% received piperacillin-tazobactam. More patients in the intermittent infusion group received meropenem (35.5% vs 24.5%; p = 0.007). Baseline characteristics were similar between groups, with the exception of a greater occurrence of chronic obstructive pulmonary disease (COPD) in the intermittent infusion group. Treatment success rates in the clinically evaluable group were 56.6% for intermittent infusion and 51.0% for prolonged infusion (p = 0.204), and in the microbiologically evaluable population, 55.2% for intermittent infusion and 49.5% for prolonged infusion (p = 0.486). Fourteen-day, 30-day, and inhospital mortality rates in the clinically evaluable population for the intermittent and prolonged infusion groups were 13.2% versus 18.0% (p = 0.141), 23.6% versus 25.7% (p = 0.582), and 19.4% versus 23.0% (p = 0.329). CONCLUSIONS: Routine use of prolonged infusion of time-dependent antibiotics for the empiric treatment of gram-negative bacterial infections offers no advantage over intermittent infusion antibiotic therapy with regard to treatment success, mortality, or hospital length of stay. These results were confirmed after controlling for potential confounders in a multivariate analysis.

Readmission Following Hospitalization for Pneumonia: The Impact of Pneumonia Type and Its Implication for Hospitals

BACKGROUND Readmission rates following discharge after pneumonia are thought to represent the quality of care. Factors associated with readmission, however, remain poorly described. It is unclear if readmission rates vary based on pneumonia type. METHODS We retrospectively identified adults admitted to an index hospital with non-nosocomial pneumonia (January through December 2010) and who survived to discharge. We only included patients with bacterial evidence of infection. Readmission in the 30 days following discharge to any of 9 hospitals comprising the index hospitals healthcare system served as the primary end point. We recorded demographics, severity of illness, comorbidities, and infection-related factors. We noted whether the patient had healthcare-associated pneumonia (HCAP) versus community-acquired pneumonia. We utilized logistic regression analysis to determine factors independently associated with readmission. RESULTS The cohort included 977 subjects; 78.9% survived to discharge. The readmission rate equaled 20%. Neither disease severity nor the rate of initially inappropriate antibiotic therapy correlated with readmission. Subjects with HCAP were 7.5 (95% confidence interval [CI], 3.6-15.7) times more likely to be readmitted. Four HCAP criteria were independently associated with readmission: admission from long-term care (adjusted odds ratio [AOR], 2.2 [95% CI, 1.4-3.4]); immunosuppression (AOR, 1.9 [95% CI, 1.3-2.9]); prior antibiotics (AOR, 1.7 [95% CI, 1.2-2.6]); and prior hospitalization (AOR, 1.7 [95% CI, 1.1-2.5]). CONCLUSIONS Readmission for pneumonia is common but varies based on pneumonia type. The variables associated with readmission do not reflect factors that hospitals directly control. Use of one rule to guide payment that fails to account for HCAP and the HCAP criteria on readmission seems inappropriate.

Bacteremia increases the risk of death among patients with soft -tissue infections

BACKGROUND Soft-tissue infections traditionally have been viewed as carrying a lower risk of death than other types of infection such as pneumonia, blood stream, and intra-abdominal. The influence of secondary bacteremia on the outcomes of patients with soft-tissue infections is not well described. OBJECTIVES To describe the risk factors for bacteremia among patients admitted to an urban medical center with soft-tissue infections and the influence of bacteremia on outcomes. METHODS A retrospective cohort study of 717 patients with culture-positive non-necrotizing soft-tissue infections admitted between April 1, 2005, and December 31, 2007. RESULTS Bacteremia was present in 52% of the patients. Increasing age, previous hospitalization, decubitus or lower-extremity ulcers, device-related soft-tissue infection, and polymicrobial infection were independent predictors of bacteremia. Intensive care unit admission (adjusted odds ratio [AOR] 3.57; 95% confidence interval [CI] 2.17, 5.86), lower-extremity ulcer (AOR 3.43; 95% CI 2.07, 5.70), and bacteremia (AOR 6.37; 95% CI 3.34, 12.12) were independent predictors of in-hospital death. When patients with device-related soft-tissue infections were excluded, the rate of secondary bacteremia was 37.6% (201/535), and it remained an independent predictor of in-hospital death. CONCLUSIONS The occurrence of bacteremia in soft-tissue infections is associated with a greater risk of death. Health care providers should be aware of the risk factors for bacteremia in patients with soft-tissue infections in order to provide more appropriate initial antimicrobial therapy and to ascertain its presence as a prognostic indicator.

Macrolides are associated with a better survival rate in patients hospitalized with community-acquired but not healthcare-associated pneumonia

BACKGROUND Macrolide-based treatment has been associated with survival benefit in patients hospitalized with community-acquired pneumonia (CAP). However, the influence of macrolide therapy in all patients hospitalized with pneumonia, including healthcare-associated pneumonia (HCAP), is unclear. METHODS Analysis of a retrospective single-center cohort. RESULTS Community-acquired pneumonia was present in 220 (22.5%) of all patients with pneumonia admitted through the emergency department of Barnes-Jewish Hospital, and HCAP was present in 757. Macrolide-based treatment was administered to 411 patients (42.1%). These patients were more likely to have CAP than were patients not receiving macrolide-based therapy (35.3% vs. 13.3%; p<0.001) and had lower scores on the CURB-65 tool, a measure of the severity of illness (2.4±1.5 vs. 3.1±1.3; p<0.001). Patients receiving macrolides also had a lower hospital mortality rate in univariable analysis (12.7% vs. 27.2%; p<0.001). A propensity score analysis showed that macrolide-based treatment was associated with a lower in-hospital mortality rate (adjusted odds ratio [AOR] 0.67; 95% confidence interval [CI] 0.54-0.81; p=0.043). Separate propensity score analyses of patients with CAP (AOR 0.20; 95% CI 0.11-0.34; p=0.003) and HCAP (AOR 0.81; 95% CI 0.65-1.01; p=0.337) produced discordant findings. CONCLUSIONS Macrolide-based treatment was associated with better survival in patients hospitalized with pneumonia. The survival advantage appeared predominantly among patients with CAP.