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Background: Central-line–associated blood stream infections (CLABSIs) are linked with significant morbidity and mortality. A NHSN laboratory-confirmed bloodstream infection (LCBSI) has specific criteria to ascribe an infection to the central line or not. The criteria used to associate the pathogen to another site are restrictive. This objective to better classify CLABSIs using enhanced criteria to gain a comprehensive understanding of the error so that appropriate reduction efforts are utilized. Methods: We conducted a retrospective review of medical records with NHSN-identified CLABSI from July 2017 to December 2018 at 2 geographically proximate hospitals. Trained infectious diseases personnel from tertiary-care academic medical centers, the University of Virginia Health System, a 600-bed medical center in Charlottesville, Virginia, and Virginia Commonwealth University Health System with 865 beds in Richmond, Virginia, reviewed charts. We defined “overcaptured” or O-CLABSI into different categories: O-CLABSI-1 is bacteremia attributable to a primary infectious source; O-CLABSI-2 is bacteremia attributable to neutropenia with gastrointestinal translocation not meeting mucosal barrier injury criteria; O-CLABSI-3 is a positive blood culture attributable to a contaminant; and O-CLABSI-4 is a patient injecting line, though not officially documented. Descriptive analyses were performed using the χ2 and the Fisher exact tests. Results: We found a large number of O-CLABSIs on chart review (79 of 192, 41%). Overall, 56 of 192 (29%) LCBSIs were attributable to a primary infectious source not meeting NHSN definition. O-CLABSI proportions between the 2 hospitals were statistically different; hospital A identified 34 of 59 (58%) of their NHSN-identified CLABSIs as O-CLABSIs, and hospital B identified a 45 of 133 (34%) as O-CLABSIs (P = .0020) (Table 1). When comparing O-CLABSI types, hospital B had a higher percentage of O-CLABSI-1 compared to hospital B: 76% versus 64%. Hospital A had a higher proportion of O-CLABSI-2: 21 versus 7%. Hospitals A and B had similar proportion of O-CLABSI-3: 15% versus 18%. These values were all statistically significant (P < .0001). Discussions: The results of these 2 geographically proximate systems indicate that O-CLABSIs are common. Attribution can vary significantly between institutions, likely depending on differences in incidence of true CLABSI, patient populations, protocols, and protocol compliance. These findings have implications for interfacility comparisons of publicly reported data. Most importantly, erroneous attribution can result in missed opportunity to direct patient safety efforts to the root cause of the bacteremia and could lead to inappropriate treatment.
Disclosures: Michelle Doll, Research Grant from Molnlycke Healthcare
Background: Urinary tract infections (UTIs) are one of the most common hospital-acquired infections; ~70%–80% are attributable to an indwelling urethral catheter. Daily risk of bacteriuria acquisition varies from 3% to 7% with a catheter. CAUTIs are associated with increased mortality, cost, and inappropriate treatment of asymptomatic bacteriuria which promotes antimicrobial resistance and Clostridium difficile infection. NHSN CAUTI criteria is most commonly met when a patient has a positive urine culture and a fever. Although fever can be associated with many sources, it cannot be excluded from UTI determination even when attributable to another recognized source. Given the high prevalence of bacteriuria in catheterized patients and the many sources of fever, the NHSN definition lacks specificity. Objective: To better classify CAUTI using enhanced criteria to so that appropriate reduction efforts would be utilized. Methods: A retrospective review was conducted to evaluate NHSN-defined CAUTIs from July 2017 to December 2018. Patients with NHSN defined CAUTI were evaluated to determine elements present to meet criteria. Overcaptured (O-CAUTIs) were defined as follows: (1) O-CAUTI 1, a positive culture with fever attributable to an infectious source; (2) O-CAUTI 2, a positive culture with fever attributable noninfectious source; (3) O-CAUTI 3, repeated positive cultures outside the RI period; (4) O-CAUTI 4, a positive culture with symptoms attributable to another source and no fever. Classifications were discussed with the medical and clinical leadership to determine appropriate opportunities for improvement. Results: Overall, 49 NHSN CAUTIs were identified with 11 of 49 (22%) being true CAUTIs and 38 of 49 (78%) O-CAUTI. O-CAUTI 1 was most common, with 17 of 38 (45%). The most frequent attributable source of fever for O-CAUTI 1 (infectious source) was respiratory (7 of 17, 59%) followed by gastrointestinal (6 of 17, 35%). Also, 14 of 38 (37%) were O-CAUTI 2. Central fever was the most frequent source of fever for the noninfectious source (9 of 14, 64%) followed by drug fever (2 of 14, 14%). Of 38 patients, 3 (8%) had both an infectious and noninfectious reason for fever (CAUTI 1 and 2); 4 patients had no fever. Furthermore, 2 were O-CAUTI 3 (repeat culture positive) and 2 were O-CAUTI 4 (1 with hematuria and renal cell carcinoma and 1 with dysuria without leukocytosis). Conclusions: NHSN CAUTI definitions capture UTIs and other events. In FY2018, there were no true CAUTIs in 5 of 12 months (42%). Also, 50% of CDC CAUTIs were not UTI but could lead to inappropriate antibiotic use. Reviewing only CAUTI reduction work in O-CAUTIs prevents the assessment of other appropriate opportunities for improvement.
Recovery of multidrug-resistant (MDR) Pseudomonas aeruginosa and Klebsiella pneumoniae from a cluster of patients in the medical intensive care unit (MICU) prompted an epidemiologic investigation for a common exposure.
Clinical and microbiologic data from MICU patients were retrospectively reviewed, MICU bronchoscopes underwent culturing and borescopy, and bronchoscope reprocessing procedures were reviewed. Bronchoscope and clinical MDR isolates epidemiologically linked to the cluster underwent molecular typing using pulsed-field gel electrophoresis (PFGE) followed by whole-genome sequencing.
Of the 33 case patients, 23 (70%) were exposed to a common bronchoscope (B1). Both MDR P. aeruginosa and K. pneumonia were recovered from the bronchoscope’s lumen, and borescopy revealed a luminal defect. Molecular testing demonstrated genetic relatedness among case patient and B1 isolates, providing strong evidence for horizontal bacterial transmission. MDR organism (MDRO) recovery in 19 patients was ultimately linked to B1 exposure, and 10 of 19 patients were classified as belonging to an MDRO pseudo-outbreak.
Surveillance of bronchoscope-derived clinical culture data was important for early detection of this outbreak, and whole-genome sequencing was important for the confirmation of findings. Visualization of bronchoscope lumens to confirm integrity should be a critical component of device reprocessing.
To determine risk factors for the development of surgical site infections (SSIs) in neurosurgery patients undergoing spinal fusion.
Retrospective case-control study.
Large, academic, quaternary care center.
The study population included all neurosurgery patients who underwent spinal fusion between August 1, 2009, and August 31, 2013. Cases were defined as patients in the study cohort who developed an SSI. Controls were patients in the study cohort who did not develop an SSI.
To achieve 80% power with an ability to detect an odds ratio (OR) of 2, we performed an unmatched case-control study with equal numbers of cases and controls.
During the study period, 5,473 spinal fusion procedures were performed by neurosurgeons in our hospital. With 161 SSIs recorded during the study period, the incidence of SSIs associated with these procedures was 2.94%. While anterior surgical approach was found to be a protective factor (OR, 0.20; 95% confidence interval [CI], 0.08–0.52), duration of procedure (OR, 1.58; 95% CI, 1.29–1.93), American Society of Anesthesiologists score of 3 or 4 (OR, 1.79; 95% CI, 1.00–3.18), and hospitalization within the prior 30 days (OR, 5.8; 95% CI, 1.37–24.57) were found in multivariate analysis to be independent predictors of SSI following spinal fusion. Prior methicillin-resistant Staphylococcus aureus (MRSA) nares colonization was highly associated with odds 20 times higher of SSI following spinal fusion (OR, 20.30; 95% CI, 4.64–8.78).
In additional to nonmodifiable risk factors, prior colonization with MRSA is a modifiable risk factor very strongly associated with development of SSI following spinal fusion.
Determining risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is important for defining infection-control measures that may lead to fewer hospital-acquired infections.
To determine patient-associated risk factors for acquisition of MRSA in a tertiary care hospital with the goal of identifying modifiable risk factors.
A retrospective matched case-control study was performed. Case patients who acquired MRSA during hospitalization and 2 matched control patients were selected among inpatients admitted to target units during the period from 2001 through 2008. The odds of exposure to potential risk factors were compared between case patients and control patients, using matched univariate conditional logistic regression. A single multivariate conditional logistic regression model identifying independent patient-specific risk factors was generated.
A total of 451 case patients and 866 control patients were analyzed. Factors positively associated with MRSA acquisition were as follows: target unit stay before index culture; primary diagnosis of respiratory disease, digestive tract disease, injury or trauma, or other diagnosis compared with cardiocirculatory disease; peripheral vascular disease; mechanical ventilation with pneumonia; ventricular shunting or ventriculostomy; and ciprofloxacin use. Factors associated with decreased risk were receipt of a solid-organ transplant and use of penicillins, cephalosporins, rifamycins, daptomycin or linezolid, and proton pump inhibitors.
Among the factors associated with increased risk, few are modifiable. Patients with at-risk conditions could be targeted for intensive surveillance to detect acquisition sooner. The association of MRSA acquisition with target unit exposure argues for rigorous application of hand hygiene, appropriate barriers, environmental control, and strict aseptic technique for all procedures performed on such Patients. Our findings support focusing efforts to prevent MRSA transmission and restriction of ciprofloxacin use.
Fluoroquinolones have not been frequently implicated as a cause of Clostridium difficile outbreaks. Nosocomial C. difficile infections increased from 2.7 to 6.8 cases per 1,000 discharges (P < .001). During the first 2 years of the outbreak, there were 253 nosocomial C. difficile infections; of these, 26 resulted in colectomy and 18 resulted in death. We conducted an investigation of a large C. difficile outbreak in our hospital to identify risk factors and characterize the outbreak.
A retrospective case-control study of case-patients with C. difficile infection from January 2000 through April 2001 and control-patients matched by date of hospital admission, type of medical service, and length of stay; an analysis of inpatient antibiotic use; and antibiotic susceptibility testing and molecular subtyping of isolates were performed.
On logistic regression analysis, clindamycin (odds ratio [OR], 4.8; 95% confidence interval [CI95], 1.9-12.0), ceftriaxone (OR, 5.4; CI95, 1.8-15.8), and levofloxacin (OR, 2.0; CI95, 1.2-3.3) were independently associated with infection. The etiologic fractions for these three agents were 10.0%, 6.7%, and 30.8%, respectively. Fluoroquinolone use increased before the onset of the outbreak (P < .001); 59% of case-patients and 41% of control-patients had received this antibiotic class. The outbreak was polyclonal, although 52% of isolates belonged to two highly related molecular subtypes.
Exposure to levofloxacin was an independent risk factor for C. difficile-associated diarrhea and appeared to contribute substantially to the outbreak. Restricted use of levofloxacin and the other implicated antibiotics may be required to control the outbreak.
Infection control programs were created three decades ago to control antibiotic-resistant healthcare-associated infections, but there has been little evidence of control in most facilities. After long, steady increases of MRSA and VRE infections in NNIS System hospitals, the Society for Healthcare Epidemiology of America (SHEA) Board of Directors made reducing antibiotic-resistant infections a strategic SHEA goal in January 2000. After 2 more years without improvement, a SHEA task force was appointed to draft this evidence-based guideline on preventing nosocomial transmission of such pathogens, focusing on the two considered most out of control: MRSA and VRE.
Medline searches were conducted spanning 1966 to 2002. Pertinent abstracts of unpublished studies providing sufficient data were included.
Frequent antibiotic therapy in healthcare settings provides a selective advantage for resistant flora, but patients with MRSA or VRE usually acquire it via spread. The CDC has long-recommended contact precautions for patients colonized or infected with such pathogens. Most facilities have required this as policy, but have not actively identified colonized patients with surveillance cultures, leaving most colonized patients undetected and unisolated. Many studies have shown control of endemic and/or epidemic MRSA and VRE infections using surveillance cultures and contact precautions, demonstrating consistency of evidence, high strength of association, reversibility, a dose gradient, and specificity for control with this approach. Adjunctive control measures are also discussed.
Active surveillance cultures are essential to identify the reservoir for spread of MRSA and VRE infections and make control possible using the CDC's long-recommended contact precautions.
Several hospitals opting not to use active surveillance cultures to identify carriers of vancomycin-resistant Enterococcus (VRE) have reported that adoption of other parts of the Centers for Disease Control and Prevention guideline for controlling VRE has had little to no impact. Because use of surveillance cultures and contact isolation controlled a large outbreak at this hospital, their costs were estimated for comparison with the excess costs of VRE bacteremias occurring at a higher rate at a hospital not employing these measures.
Two university hospitals.
Inpatients deemed high risk for VRE acquisition at this hospital underwent weekly perirectal surveillance cultures. Estimated costs of cultures and resulting isolation during a 2-year period were compared with the estimated excess costs of more frequent VRE bacteremias at another hospital of similar size and complexity not using surveillance cultures to control spread throughout the hospital.
Of 54,052 patients admitted, 10,400 had perirectal swabs taken. Cultures and isolation cost an estimated $253,099. VRE culture positivity was limited to 193 (0.38%) and VRE bacteremia to 1 (0.002%) as compared with 29 bacteremias at the comparison hospital. The estimated attributable cost of VRE bacteremia at the comparison hospital of $761,320 exceeded the cost of the control program at this hospital by threefold.
The excess costs of VRE bacteremia may justify the costs of preventive measures. The costs of VRE infections at other body sites, of deaths from untreatable infections, and of dissemination of genes for vancomycin resistance also help to justify the costs of implementing an effective control program.
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