Thomas G. Fraser

Cardiac implantable electronic device infections: Presentation, management, and patient outcomes

BACKGROUND Indications for cardiac implantable electronic devices (CIEDs) are increasing. Although CIED infections occur infrequently, the impact of this outcome is expected to be substantial. OBJECTIVE The purpose of this study was to the evaluate the outcome of patients undergoing removal of infected CIEDs. METHODS A retrospective study was conducted of all patients with proven or suspected infected CIEDs who were referred to the Cleveland Clinic for system removal from January 2002 through March 2007. RESULTS A total of 412 patients (age 68 +/- 15 years) were included in the study. The majority of patients (241 [59%]) presented with localized infection involving the device pocket. The remaining 171 patients (41%) presented with endovascular infection but no evidence of inflammation of the device pocket. Of the total 414 pathogens isolated, 366 (88%) were aerobic gram-positive organisms, of which 90% were Staphylococcus species, and almost half of these were methicillin resistant. In-hospital mortality was 4.6% (19 patients). Only 2 deaths were extraction related. One-year mortality was 17%. Among the total cohort, 8 (1.9%) patients had relapsing infection within the first year. Among patients who had device replacement during the same hospitalization, 6 (2.6%) had relapsing infections within 1 year of reimplantation; 5 of these patients had systemic symptoms and were bacteremic upon initial presentation. CONCLUSION CIED infections are most often caused by Staphylococcus species, half of which are methicillin resistant. Percutaneous lead and device removal along with antibiotic therapy are effective as primary interventions. The overall relapse rate is 1.9%, and the relapse rate among patients who had reimplantation during the same hospitalization is 2.6%.

Treatment and Outcomes in Carbapenem-resistant Klebsiella pneumoniae Bloodstream Infections

Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) is an emerging multidrug-resistant nosocomial pathogen. This is a retrospective chart review describing the outcomes and treatment of 60 cases of CR-Kp bloodstream infections. All CR-Kp isolated from blood cultures were identified retrospectively from the microbiology laboratory from January 2007 to May 2009. Clinical information was collected from the electronic medical record. Patients with 14-day hospital mortality were compared to those who survived 14 days. The all-cause in-hospital and 14-day mortality for all 60 CR-Kp bloodstream infections were 58.3% and 41.7%, respectively. In this collection, 98% of tested isolates were susceptible in vitro to tigecycline compared to 86% to colistimethate, 45% to amikacin, and 22% to gentamicin. Nine patients died before cultures were finalized and received no therapy active against CR-Kp. In the remaining 51 patients, those who survived to day 14 (n = 35) were compared to nonsurvivors at day 14 (n=16). These patients were characterized by both chronic disease and acute illness. The 90-day readmission rate for hospital survivors was 72%. Time to active therapy was not significantly different between survivors and nonsurvivors, and hospital mortality was also similar regardless of therapy chosen. Pitt bacteremia score was the only significant factor associated with mortality in Cox regression analysis. In summary, CR-Kp bloodstream infections occur in patients who are chronically and acutely ill. They are associated with high 14-day mortality and poor outcomes regardless of tigecycline or other treatment regimens selected.

Challenges of Interferon-γ Release Assay Conversions in Serial Testing of Health-care Workers in a TB Control Program

BACKGROUND Clinical data with use of serial interferon-γ release assay (IGRA) testing in US health-care workers (HCWs) are limited. METHODS A single-center, retrospective chart review was done from 2007 to 2010 of HCWs who underwent preemployment QuantiFERON-TB Gold In-Tube testing. Demographic data, bacille Calmette-Guérin history, prior tuberculin skin test result if done, and baseline and serial IGRA values were obtained. The number of IGRA converters and reverters and their subsequent management by infectious disease physicians were reviewed. Quantitative IGRA-negative values were not available. RESULTS A total of 7,374 IGRAs were performed on newly hired HCWs. Of these tests, 486 (6.6%) were positive at baseline, 305 (4.1%) were indeterminate, and 6,583 (89.3%) were negative. From 2007 to 2010, 52 of 1,857 HCWs (2.8%) with serial IGRA tests were identified as converters, with a serial IGRA median value of 0.63 IU/mL. Seventy-one percent of HCWs with IGRA conversion had values ≤ 1 IU/mL. None of the converters had active TB or were part of an outbreak investigation. CONCLUSIONS Clinical significance of most QuantiFERON-TB Gold In-Tube conversions in serial testing remains a challenging task for clinicians. The use of a single cutoff point criterion for IGRA may lead to overdiagnosis of new TB infections. Clinical assessment and evaluation may help to prevent unnecessary therapy in these cases. The criteria for defining conversions and reversions by establishing new cutoffs needs to be evaluated further, especially in HCWs.

Do fluoroquinolones predispose patients to Clostridium difficile associated disease? A review of the evidence

ABSTRACT Background: Clostridium difficile associated diarrhea (CDAD) is an important cause of hospital-acquired diarrhea, and increasingly of community-acquired diarrhea. The occurrence of CDAD in the hospitalized patient is associated with increased length of stay, morbidity, mortality, and healthcare costs. Exposure to antimicrobials is the single most important predisposing factor for acquiring CDAD. The data suggesting that fluoroquinolones are an important risk factor for CDAD is becoming stronger. Also, different fluoroquinolones may pose different risks for CDAD development. Objectives: The aim of this commentary is to summarize the literature as it relates to the role that fluoroquinolones may have in CDAD. Methods: PubMed and Ovid MEDLINE were searched using the terms fluoroquinolones, ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin in combination with C. difficile, CDAD, pseudomembranous colitis and antibiotic associated diarrhea. Results: The evidence for an association between fluoroquinolone use and CDAD, especially CDAD due to the hypervirulent NAP1 strain or the polymerase chain reaction ribotype 027, is becoming stronger. Conclusions: Fluoroquinolones appear to predispose patients to CDAD. The data are suggestive but not conclusive. More studies are needed to define the role that fluoroquinolones play in the development of CDAD. Meticulous and enhanced infection control practices at all times and the judicious use of antimicrobials will help contain the epidemic of CDAD.

Risk Factors for Recurrent Clostridium difficile Infection: A Systematic Review and Meta-Analysis

OBJECTIVE An estimated 20-30% of patients with primary Clostridium difficile infection (CDI) develop recurrent CDI (rCDI) within 2 weeks of completion of therapy. While the actual mechanism of recurrence remains unknown, a variety of risk factors have been suggested and studied. The aim of this systematic review and meta-analysis was to evaluate current evidence on the risk factors for rCDI. DESIGN We searched MEDLINE and 5 other databases for subject headings and text related to rCDI. All studies investigating risk factors of rCDI in a multivariate model were eligible. Information on study design, patient population, and assessed risk factors were collected. Data were combined using a random-effects model and pooled relative risk ratios (RRs) were calculated. RESULTS A total of 33 studies (n=18,530) met the inclusion criteria. The most frequent independent risk factors associated with rCDI were age≥65 years (risk ratio [RR], 1.63; 95% confidence interval [CI], 1.24-2.14; P=.0005), additional antibiotics during follow-up (RR, 1.76; 95% CI, 1.52-2.05; P<.00001), use of proton-pump inhibitors (PPIs) (RR, 1.58; 95% CI, 1.13-2.21; P=.008), and renal insufficiency (RR, 1.59; 95% CI, 1.14-2.23; P=.007). The risk was also greater in patients previously on fluoroquinolones (RR, 1.42; 95% CI, 1.28-1.57; P<.00001). CONCLUSIONS Multiple risk factors are associated with the development of rCDI. Identification of modifiable risk factors and judicious use of antibiotics and PPI can play an important role in the prevention of rCDI.

Outcomes After Surgical Treatment of Native and Prosthetic Valve Infective Endocarditis

BACKGROUND The risk of death and complications of infective endocarditis (IE) treated medically has to be balanced against those from surgery in constructing a therapeutic approach. Recent literature has drawn conflicting conclusions on the benefit of surgery for IE. We reviewed patients treated surgically for IE at the Cleveland Clinic from 2003 to 2007 to examine their outcomes. METHODS A retrospective review of consecutive patients who underwent surgery for native and prosthetic valve endocarditis between January 1, 2003, and December 31, 2007, was conducted. Surgical outcomes were reviewed to include survival and postoperative complications. Survival was evaluated at end of hospital stay, 30 days, 1 year, and at last follow-up. RESULTS Four hundred twenty-eight patients underwent surgery for IE during the study period: 248 (58%) had native valve endocarditis and 180 (42%) had prosthetic valve endocarditis. Overall 90% of patients survived to hospital discharge. When compared with patients with native valve infection, patients with prosthetic infection had significantly higher 30-day mortality (13% versus 5.6%; p<0.01), but long-term survival was not significantly different (35% versus 29%; p=0.19). Patients with IE caused by Staphylococcus aureus had significantly higher hospital mortality (15% versus 8.4%; p<0.05), 6-month mortality (23% versus 15%; p=0.05), and 1-year mortality (28% versus 18%; p=0.02) compared with non-S aureus IE. CONCLUSIONS Surgical treatment of IE was associated with 90% hospital survival. Outcomes within the 30 days were better for native valve than for prosthetic valve endocarditis. Long-term outcomes were similar. Finally, S aureus was associated with significantly higher mortality compared with other pathogens.

Impact of PCR testing for Clostridium difficile on incident rates and potential on public reporting: is the playing field level?

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CLABSI Rates in Immunocompromised Patients: A Valuable Patient Centered Outcome?

The accepted approach to surveillance for hospital-acquired bloodstream infection (HABSI) due to central venous catheters requires use of the National Health and Safety Network (NHSN) definition for catheter-associated bloodstream infection (CLABSI). In this commentary, we discuss our experience with the application of current NHSN surveillance definitions for CLABSI and the impact that public reporting of CLABSI rates in settings with a high prevalence of special populations has on infection prevention (IP) programs. For IP programs to serve the continuous improvement needs of their organizations, surveillance methodologies need to accurately capture the burden of preventable HABSI among immunocompromised individuals with inherent risk for infection. Current NHSN CLABSI definitions lack specificity for complex and heterogeneous patient populations and require modification. Beyond definitions, IP programs must critically assess the value of their current approach to surveillance to assure that patient-centered outcomes are the focus of prevention efforts.

Multidrug-resistant Pseudomonas aeruginosa cholangitis after endoscopic retrograde cholangiopancreatography: failure of routine endoscope cultures to prevent an outbreak.

BACKGROUND Nosocomial infections due to medical devices are of increasing concern to infection control practitioners. Attempts to prevent such infections have included surveillance cultures of endoscopes and bronchoscopes. In July 2002, the infectious disease consultation service was asked to see three patients with sepsis due to multidrug-resistant Pseudomonas aeruginosa after endoscopic retrograde cholangiopancreatography (ERCP). OBJECTIVE To describe an outbreak of multidrug-resistant P. aeruginosa sepsis after ERCP at an institution that performs routine surveillance cultures of endoscopes. DESIGN A traditional outbreak investigation supplemented by pulsed-field gel electrophoresis (PFGE) was undertaken, including a case-control analysis based on the hypothesis that all infected individuals had their ERCP performed with the same endoscope. SETTING A tertiary-care academic medical center. RESULTS The case-control analysis confirmed the hypothesis that undergoing ERCP with the implicated endoscope was associated with a culture positive for Pseudomonas (P = .01). The available strains were identical by PFGE. This outbreak occurred despite a negative surveillance culture of the implicated endoscope 1 month earlier. CONCLUSIONS Infectious morbidity can occur after endoscopy despite negative surveillance cultures. The practice of routine endoscope cultures does not prevent device-related infectious morbidity.

Decrease in Staphylococcus aureus colonization and hospital-acquired infection in a medical intensive care unit after institution of an active surveillance and decolonization program.

OBJECTIVE To evaluate the effects of an active surveillance program for Staphylococcus aureus linked to a decolonization protocol on the incidence of healthcare-associated infection and new nasal colonization due to S. aureus. DESIGN Retrospective quasi-experimental study. SETTING An 18-bed medical intensive care unit at a tertiary care center in Cleveland, Ohio. METHODS From January 1, 2006, through December 31, 2007, all patients in the medical intensive care unit were screened for S. aureus nasal carriage at admission and weekly thereafter. During the preintervention period, January 1 through September 30, 2006, only surveillance occurred. During the intervention period, January 1 through December 31, 2007, S. aureus carriers received mupirocin intranasally. Beginning in February 2007, carriers also received chlorhexidine gluconate baths. RESULTS During the preintervention period, 604 (73.7%) of 819 patients were screened for S. aureus nasal carriage, yielding 248 prevalent carriers (30.3%). During the intervention period, 752 (78.3%) of 960 patients were screened, yielding 276 carriers (28.8%). The incidence of S. aureus carriage decreased from 25 cases in 3,982 patient-days (6.28 cases per 1,000 patient-days) before intervention to 18 cases in 5,415 patient-days (3.32 cases per 1,000 patient-days) (P=.04; relative risk [RR], 0.53 [95% confidence interval {CI}, 0.28-0.97]) and from 9.57 to 4.77 cases per 1,000 at-risk patient-days (P=.02; RR, 0.50 [95% CI, 0.27-0.91]). The incidence of S. aureus hospital-acquired bloodstream infection during the 2 periods was 2.01 and 1.11 cases per 1,000 patient-days, respectively (P=.28). The incidence of S. aureus ventilator-associated pneumonia decreased from 1.51 to 0.18 cases per 1,000 patient-days (P=.03; RR, 0.12 [95% CI, 0.01-0.83]). The total incidence of S. aureus hospital-acquired infection decreased from 3.52 to 1.29 cases per 1,000 patient-days (P=.03; RR, 0.37 [95% CI, 0.14-0.90]). CONCLUSIONS Active surveillance for S. aureus nasal carriage combined with decolonization was associated with a decreased incidence of S. aureus colonization and hospital-acquired infection.