Laura Johnson

Community-Associated Extended-Spectrum β-Lactamase–Producing Escherichia coli Infection in the United States

Background. The occurrence of community-associated infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has been recognized as a major clinical problem in Europe and other regions. Methods. We conducted a prospective observational study to examine the occurrence of community-associated infections due to ESBL-producing E. coli at centers in the United States. Five academic and community hospitals and their affiliated clinics participated in this study in 2009 and 2010. Sites of acquisition of the organisms (community-associated or healthcare-associated), risk factors, and clinical outcome were investigated. Screening for the global epidemic sequence type (ST) 131 and determination of the ESBL types was conducted by polymerase chain reaction and sequencing. Results. Of the 291 patients infected or colonized with ESBL-producing E. coli as outpatients or within 48 hours of hospitalization, 107 (36.8%) had community-associated infection (81.5% of which represented urinary tract infection), while the remainder had healthcare-associated infection. Independent risk factors for healthcare-associated infection over community-associated infection were the presence of cardiovascular disease, chronic renal failure, dementia, solid organ malignancy, and hospitalization within the previous 12 months. Of the community-associated infections, 54.2% were caused by the globally epidemic ST131 strain, and 91.3% of the isolates produced CTX-M-type ESBL. Conclusions. A substantial portion of community-onset, ESBL-producing E. coli infections now occur among patients without discernible healthcare-associated risk factors in the United States. This epidemiologic shift has implications for the empiric management of community-associated infection when involvement of E. coli is suspected.

Contact Precautions: More Is Not Necessarily Better

OBJECTIVE To determine whether increases in contact isolation precautions are associated with decreased adherence to isolation practices among healthcare workers (HCWs). DESIGN Prospective cohort study from February 2009 to October 2009. SETTING Eleven teaching hospitals. PARTICIPANTS HCWs. METHODS One thousand thirteen observations conducted on HCWs. Additional data included the number of persons in isolation, types of HCWs, and hospital-specific contact precaution practices. Main outcome measures included compliance with individual components of contact isolation precautions (hand hygiene before and after patient encounter, donning of gown and glove upon entering a patient room, and doffing upon exiting) and overall compliance (all 5 measures together) during varying burdens of isolation. RESULTS Compliance with hand hygiene was as follows: prior to donning gowns/gloves, 37.2%; gowning, 74.3%; gloving, 80.1%; doffing of gowns/gloves, 80.1%; after gown/glove removal, 61%. Compliance with all components was 28.9%. As the burden of isolation increased (20% or less to greater than 60%), a decrease in compliance with hand hygiene (43.6%-4.9%) and with all 5 components (31.5%-6.5%) was observed. In multivariable analysis, there was an increase in noncompliance with all 5 components of the contact isolation precautions bundle (odds ratio [OR], 6.6 [95% confidence interval (CI), 1.15-37.44]; P = .03) and in noncompliance with hand hygiene prior to donning gowns and gloves (OR, 10.1 [95% CI, 1.84-55.54]; P = .008) associated with increasing burden of isolation. CONCLUSIONS As the proportion of patients in contact isolation increases, compliance with contact isolation precautions decreases. Placing 40% of patients under contact precautions represents a tipping point for noncompliance with contact isolation precautions measures.

Comparative Effectiveness of Two Catheter Locking Solutions to Reduce Catheter-Related Bloodstream Infection in Hemodialysis Patients

BACKGROUND AND OBJECTIVES Infection is the second leading cause of death in hemodialysis patients. Catheter-related bloodstream infection and infection-related mortality have not improved in this population over the past two decades. This study evaluated the impact of a prophylactic antibiotic lock solution on the incidence of catheter-related bloodstream infection and mortality. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This prospective, multicenter, observational cohort study compared the effectiveness of two catheter locking solutions (gentamicin/citrate versus heparin) in 555 hemodialysis patients dialyzing with a tunneled cuffed catheter between 2008 and 2011. The groups were not mutually exclusive. Rates of catheter-related bloodstream infection and mortality hazards were compared between groups. RESULTS The study population (n=555 and 1350 catheters) had a median age of 62 years (interquartile range=41-83 years), with 50% men and 71% black. There were 427 patients evaluable in the heparin period (84,326 days) and 322 patients evaluable in the antibiotic lock period (71,192 days). Catheter-related bloodstream infection in the antibiotic lock period (0.45/1000 catheter days) was 73% lower than the heparin period (1.68/1000 catheter days; P=0.001). Antibiotic lock use was associated with a decreased risk of catheter-related bloodstream infection compared with heparin (risk ratio, 0.23; 95% confidence interval, 0.13 to 0.38 after multivariate adjustment). Cox proportional hazards modeling found that antibiotic lock was associated with a reduction in mortality (hazard ratio, 0.36; 95% confidence interval, 0.22 to 0.58 in unadjusted analyses; hazard ratio, 0.32; 95% confidence interval, 0.14 to 0.75 after multivariate adjustment). The rate of gentamicin-resistant organisms decreased (0.40/1000 person-years to 0.22/1000 person-years) in the antibiotic lock period (P=0.01). CONCLUSIONS The results of this study show that the use of a prophylactic, gentamicin/citrate lock was associated with a substantial reduction in catheter-related bloodstream infection and is the first to report a survival advantage of antibiotic lock in a population at high risk of infection-related morbidity and mortality.

Clinical and Microbiologic Characteristics of Cephalosporin-Resistant Escherichia coli at Three Centers in the United States

ABSTRACT We investigated the clinical and microbiologic features of 300 cases of cephalosporin-resistant Escherichia coli producing extended-spectrum β-lactamase (ESBL) or plasmid-mediated AmpC β-lactamase (pAmpC) at three medical centers in the United States. Solid-organ malignancy, connective tissue disease, and a recent history of surgery were more common among pAmpC-producing cases (n = 49), whereas urinary catheter at enrollment, diabetes, and hospitalization in the past year were more common among ESBL-producing cases (n = 233). The factors independently associated with clinical outcome were the following: the presence of cardiovascular disease (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.29 to 6.43), intra-abdominal infection (OR, 6.35; 95% CI, 1.51 to 26.7), other or multiples sources of infection (OR, 8.12; 95% CI, 2.3 to 28.6), age of 65 years or greater (OR, 0.43; 95% CI, 0.2 to 0.95), favorable baseline health status (OR, 0.39; 95% CI, 0.16 to 0.95), and appropriate empirical antimicrobial therapy given in the first 72 h (OR, 0.42; 95% CI, 0.20 to 0.88). β-Lactamase genes responsible for cephalosporin resistance were identified in 291 cases. CTX-M-type ESBLs accounted for 72.0%. Of those, 88.0% were CTX-M-15. The next most common type was CMY-type pAmpC (16.7%), followed by SHV- and TEM-type ESBLs (6.3 and 1.3%, respectively). Seven cases (2.3%) had KPC-type β-lactamase. Ertapenem, imipenem, meropenem, doripenem, piperacillin-tazobactam, amikacin, nitrofurantoin, and tigecycline were highly active, with greater than 90% of the isolates being susceptible. Cefepime was less active, with only 74.2% being susceptible due to the predominance of CTX-M-15. These findings have implications in the selection of appropriate empirical therapy when infection due to cephalosporin-resistant E. coli is suspected.

Evaluation of Risk Factors for Coinfection or Cocolonization with Vancomycin-Resistant Enterococcus and Methicillin-Resistant Staphylococcus aureus

ABSTRACT We retrospectively evaluated 410 patients with coinfection or cocolonization due to vancomycin-resistant (VR) enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA). The prevalence rate was 19.8%. Risk factors included isolation of VR Enterococcus faecalis and use of linezolid or clindamycin. Inc18-like vanA plasmids were found in 7% of VR E. faecalis isolates and none of the VR E. faecium isolates.

Sequence type ST405 Escherichia coli isolate producing QepA1, CTX-M-15, and RmtB from Detroit, Michigan.

Plasmid-mediated fluoroquinolone resistance determinants are increasingly identified worldwide among various isolates of Enterobacteriaceae (9).…

Commensal Escherichia coli Isolate Resistant to Eight Classes of Antimicrobial Agents in the United States

To increase understanding of community-acquired resistance, stool samples from 477 nonhospitalized persons in Maryland and Michigan, from 2004 to 2008, were screened for ceftriaxone resistance. Seven (1.5%) yielded ceftriaxone-resistant Escherichia coli; one isolate was resistant to all eight antimicrobial classes routinely tested: aminoglycosides, β-lactam/β-lactamase inhibitor combinations, cephems, penicillins, folate pathway inhibitors, phenicols, quinolones, and tetracyclines. The extensively resistant isolate was from a 50-year-old woman who denied antimicrobial use, hospitalization, or international travel within 6 months. Meat (beef, chicken, and pork) and eggs were consumed within 1 month before stool collection. Further studies are warranted to understand potential sources, including the food supply, of resistant E. coli.

Resources for Infection Prevention and Control on the World Wide Web

This review summarizes infection prevention resources on the Internet. Web sites are presented in 8 categories: guidelines, policies, and regulatory bodies; health care-associated infection and multidrug-resistant organisms; surveillance, reporting, and initiatives; antibiotic use; employee health; long-term care facilities; facility and environmental infection control; and professional societies, educational opportunities, and listserves. For example, links to the National Surgical Quality Improvement Program and National Healthcare Safety Network reports are provided among resources for infection surveillance, reporting, and initiatives. A link to guidelines for infection prevention in health care workers is listed with other information regarding employee health. The Web address for the Society for Healthcare Epidemiology of America guidelines for infection control in long-term care facilities is listed with resources for long-term care facilities. Guidelines for construction and environmental services are summarized with other information regarding facility and environmental infection control. This review summarizes the most useful and up-to-date infection prevention resources on the Internet and will simplify the search for pertinent information.

Evaluation of contact precautions for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus

HighlightsThere remain limited data on the use of contact precautions (CPs) and its effect on hospital‐acquired infections (HAIs) of resistant organisms, including methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant Enterococcus (VRE).Our study demonstrates the effect of discontinuing CPs for MRSA and VRE on HAI rates.Discontinuing CPs did not adversely affect the endemic MRSA and VRE HAI rates in our institution. Background: There are limited controlled data demonstrating contact precautions (CPs) prevent methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant Enterococcus (VRE) infections in endemic settings. We evaluated changes in hospital‐acquired MRSA and VRE infections after discontinuing CPs for these organisms. Methods: This is a retrospective study done at an 800‐bed teaching hospital in urban Detroit. CPs for MRSA and VRE were discontinued hospital‐wide in 2013. Data on MRSA and VRE catheter‐associated urinary tract infections (CAUTIs), ventilator‐associated pneumonia (VAP), central line–associated bloodstream infections (CLABSIs), surgical site infections (SSIs), and hospital‐acquired MRSA bacteremia (HA‐MRSAB) rates were compared before and after CPs discontinuation. Results: There were 36,907 and 40,439 patients hospitalized during the two 12‐month periods: CPs and no CPs. Infection rates in the CPs and no‐CPs periods were as follows: (1) MRSA infections: VAP, 0.13 versus 0.11 (P = .84); CLABSI, 0.11 versus 0.19 (P = .45); SSI, 0 versus 0.14 (P = .50); and CAUTI, 0.025 versus 0.033 (P = .84); (2) VRE infections: CAUTI, 0.27 versus 0.13 (P = .19) and CLABSI, 0.29 versus 0.3 (P = .94); and (3) HA‐MRSAB rates: 0.14 versus 0.11 (P = .55), respectively. Conclusions: Discontinuation of CPs did not adversely impact endemic MRSA and VRE infection rates.

Predictors of Clostridium difficile infection-related mortality among older adults

BACKGROUND Over 90% of annual deaths caused by Clostridium difficile infection (CDI) occur in persons aged ≥65 years. However, no large-scale studies have been conducted to investigate predictors of CDI-related mortality among older adults. METHODS This case-control study included 540 CDI patients aged ≥60 years admitted to a tertiary care hospital in Detroit, Michigan, between January 2005 and December 2012. Cases were CDI patients who died within 30 days of CDI date. Controls were CDI patients who survived >30 days after CDI date. Cases were matched to controls on a 1:3 ratio based on age and hospital acquisition of CDI. RESULTS One-hundred and thirty cases (25%) were compared with 405 controls (75%). Independent predictors of CDI-related mortality included admission from another acute hospital (odds ratio [OR], 8.25; P = .001) or a long-term care facility (OR, 13.12; P = .012), McCabe score ≥2 (OR, 12.19; P < .001), and high serum creatinine (≥1.7 mg/dL) (OR, 3.43; P = .021). The regression model was adjusted for the confounding effect of limited activity of daily living score, total number of antibiotic days prior to CDI, ileus on abdominal radiograph, low albumin (≤2.5 g/dL), elevated white blood cell count (>15 × 1,000/mm3), and admission to intensive care unit because of CDI. CONCLUSIONS Predictors of CDI-related mortality reported in this study could be applied to the development of a bedside scoring system for older adults with CDI.