Darren R. Linkin

Clinical and Microbiological Outcomes of Serious Infections with Multidrug-Resistant Gram-Negative Organisms Treated with Tigecycline

Eighteen patients received tigecycline as treatment for infection due to multidrug-resistant gram-negative bacilli, including Acinetobacter baumannii and Klebsiella pneumoniae carbapenemase- and extended-spectrum beta-lactamase-producing Enterobacteriaceae. Pretherapy minimum inhibitory concentration values for tigecycline predicted clinical success. Observed evolution of resistance during therapy raises concern about routine use of tigecycline in treatment of such infections when other therapies are available.

Applicability of Healthcare Failure Mode and Effects Analysis to Healthcare Epidemiology: Evaluation of the Sterilization and Use of Surgical Instruments

Healthcare Failure Mode and Effects Analysis (HFMEA) is a methodology for correcting latent system errors before they lead to adverse events. We examined the utility of HFMEA in evaluating the sterilization and use of surgical instruments. First, a multidisciplinary team graphed the process in a flow diagram. A hazard analysis was then used to examine potential failure modes (i.e., ways in which a process can fail) and their causes and to score the severity and other factors for each failure mode cause. Actions were then planned to address the selected failure mode causes. Flow charts were created for 3 foci: sterilization process, reading of biologicals, and use of equipment. Information was gathered through interviews and a review of the literature. Multiple clinically significant system errors were identified, and actions to correct them were developed. The HFMEA methodology facilitated the detection of previously unrecognized system errors, demonstrating its potential utility in addressing healthcare epidemiology-related adverse events.

Longitudinal trends in antimicrobial susceptibilities across long-term-care facilities: Emergence of fluoroquinolone resistance

BACKGROUND Antibiotic resistance in the longterm-care facility (LTCF) setting is of increasing concern due to both the increased morbidity and mortality related to infections in this debilitated population and the potential for transfer of resistant organisms to other healthcare settings. Longitudinal trends in antibiotic resistance in LTCFs have not been well described. DESIGN Correlational longitudinal survey study. SETTING Four LTCFs in Pennsylvania. SUBJECTS All clinical cultures of residents of the participating LTCFs (700 total beds) from 1998 through 2003. We assessed the annual prevalence of resistance to various antimicrobials of interest for the following organisms: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and enterococcus species. RESULTS A total of 4,954 clinical isolates were obtained during the study. A high prevalence of antimicrobial resistance was noted for many organism-drug combinations. This was especially true for fluoroquinolone susceptibility among the Enterobacteriaceae (susceptibility range, 51.3% to 92.2%). In addition, the prevalence of resistance to various agents differed significantly across study sites. Finally, significant increasing trends in resistance were noted over time and were most pronounced for fluoroquinolone susceptibility among the Enterobacteriaceae. CONCLUSIONS The prevalence of antimicrobial resistance has increased significantly in LTCFs, although trends have varied substantially across different institutions. These trends have been particularly pronounced for fluoroquinolone resistance among the Enterobacteriaceae. These findings demonstrate that antimicrobial resistance is widespread and increasing in LTCFs, highlighting the need for future studies to more clearly elucidate the risk factors for, and potential interventions against, emerging resistance in these settings.

Risk factors for extended-spectrum beta-lactamase-producing Enterobacteriaceae in a neonatal intensive care unit.

Risk factors for colonization or infection with extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae during an outbreak in a neonatal intensive care unit (NICU) included low gestational age and exposure to third-generation cephalosporins. We also reviewed the existing medical literature regarding the clinical epidemiology of ESBLs in NICUs .

Evaluation of Antimicrobial Therapy Orders Circumventing an Antimicrobial Stewardship Program: Investigating the Strategy of “Stealth Dosing”

OBJECTIVE Prior-approval antimicrobial stewardship programs (ASPs) improve patient outcomes and decrease antimicrobial resistance. These benefits would be limited if physicians circumvented ASP efforts. We evaluated whether prescribers wait until after the prior-approval period to order restricted antimicrobial therapy that is in conflict with guidelines or unnecessary. DESIGN A cross-sectional study design and a retrospective cohort study design. SETTING A tertiary care, academic medical center with a prior-approval ASP that was active between 8 am and 10 pm. METHODS We evaluated whether there was an increase in the proportion of orders for antimicrobial therapy that involve restricted (vs nonrestricted) antimicrobials during the first hour that the ASP is inactive (ie, the first hour that prior approval is not required), compared with the remainder of the day. We also evaluated whether restricted antimicrobial therapy ordered during this first hour is less likely to be continued when the ASP becomes active the next day, compared with that ordered during the preceding hour. RESULTS A greater proportion of the antimicrobial therapy orders placed between 10:00 pm and 10:59 pm were for restricted agents, compared with orders placed during other periods (57.0% vs 49.9%; P=.02). Surgical patients for whom antimicrobial therapy orders were placed between 10:00 pm and 10:59 pm were less likely to have that antimicrobial therapy continued, compared with patients whose therapy was ordered between 9:00 pm and 9:59 pm (60.0% vs 98.1%; P<.001). Nonsurgical patients whose therapy orders were placed between 10:00 pm and 10:59 pm were also less likely to have the ordered antimicrobial therapy continued, compared with patients whose therapy was ordered between 9:00 pm and 9:59 pm (70.8% vs 84.2%; P=.01). CONCLUSION Physicians avoid having to obtain prior approval for therapy involving restricted antimicrobials by waiting until restrictions are no longer active to place orders. Compared with restricted antimicrobial therapy ordered when the ASP is active, these courses of therapy are less often continued by the ASP, suggesting that they are more likely to be in conflict with guidelines or unnecessary.

Duration of Colonization and Determinants of Earlier Clearance of Colonization With Methicillin-Resistant Staphylococcus aureus

BACKGROUND The duration of colonization and factors associated with clearance of methicillin-resistant Staphylococcus aureus (MRSA) after community-onset MRSA skin and soft-tissue infection (SSTI) remain unclear. METHODS We conducted a prospective cohort study of patients with acute MRSA SSTI presenting to 5 adult and pediatric academic hospitals from 1 January 2010 through 31 December 2012. Index patients and household members performed self-sampling for MRSA colonization every 2 weeks for 6 months. Clearance of colonization was defined as negative MRSA surveillance cultures during 2 consecutive sampling periods. A Cox proportional hazards regression model was developed to identify determinants of clearance of colonization. RESULTS Two hundred forty-three index patients were included. The median duration of MRSA colonization after SSTI diagnosis was 21 days (95% confidence interval [CI], 19-24), and 19.8% never cleared colonization. Treatment of the SSTI with clindamycin was associated with earlier clearance (hazard ratio [HR], 1.72; 95% CI, 1.28-2.30; P < .001). Older age (HR, 0.99; 95% CI, .98-1.00; P = .01) was associated with longer duration of colonization. There was a borderline significant association between increased number of household members colonized with MRSA and later clearance of colonization in the index patient (HR, 0.85; 95% CI, .71-1.01; P = .06). CONCLUSIONS With a systematic, regular sampling protocol, duration of MRSA colonization was noted to be shorter than previously reported, although 19.8% of patients remained colonized at 6 months. The association between clindamycin and shorter duration of colonization after MRSA SSTI suggests a possible role for the antibiotic selected for treatment of MRSA infection.

Identification of Optimal Combinations for Empirical Dual Antimicrobial Therapy of Pseudomonas aeruginosa Infection: Potential Role of a Combination Antibiogram

To better determine the optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection, we evaluated the utility of a novel combination antibiogram. Although the combination antibiogram allowed modest fine-tuning of choices for dual antibiotic therapy, selections based on the 2 antibiograms did not differ substantively. Drug combinations with the broadest coverage were consistently composed of an aminoglycoside and a beta-lactam.

Comparative Effectiveness of High-Dose versus Standard-Dose Influenza Vaccination in Community-Dwelling Veterans

BACKGROUND Influenza is a significant cause of morbidity and mortality in older adults. High-dose (HD) trivalent inactivated vaccine has increased immunogenicity in older adults compared with standard-dose (SD) vaccine. We assessed the relative effectiveness of HD influenza vaccination (vs SD influenza vaccination). METHODS We conducted a retrospective cohort study among patients who receive primary care at Veteran Health Administration (VHA) medical centers, and who received influenza vaccine in the 2010-2011 influenza season. The primary outcome was hospitalization for influenza or pneumonia. We also conducted an analysis in subgroups defined by age. RESULTS We evaluated 25 714 patients who received HD vaccine and 139 511 who received SD vaccine in 23 VHA medical centers. The rate of hospitalization for influenza or pneumonia was 0.3% in both groups in the influenza season. After accounting for patient characteristics in propensity-adjusted analyses, the risk of hospitalization for influenza or pneumonia was not significantly lower among patients receiving HD vaccine vs those receiving SD vaccine (risk ratio, 0.98; 95% confidence interval, .68-1.40). In the subgroup of patients ≥85 years of age, receiving HD (compared with SD) vaccine was associated with lower rates of hospitalization for influenza or pneumonia. CONCLUSIONS HD vaccine was not found to be more effective than SD vaccine in protecting against hospitalization for influenza or pneumonia; however, we found a protective effect in the oldest subgroup of patients. Additional studies are needed to evaluate the effectiveness of HD vaccine.

Lessons Learned From Hospital Ebola Preparation

BACKGROUND Hospital Ebola preparation is underway in the United States and other countries; however, the best approach and resources involved are unknown. OBJECTIVE To examine costs and challenges associated with hospital Ebola preparation by means of a survey of Society for Healthcare Epidemiology of America (SHEA) members. DESIGN Electronic survey of infection prevention experts. RESULTS A total of 257 members completed the survey (221 US, 36 international) representing institutions in 41 US states, the District of Columbia, and 18 countries. The 221 US respondents represented 158 (43.1%) of 367 major medical centers that have SHEA members and included 21 (60%) of 35 institutions recently defined by the US Centers for Disease Control and Prevention as Ebola virus disease treatment centers. From October 13 through October 19, 2014, Ebola consumed 80% of hospital epidemiology time and only 30% of routine infection prevention activities were completed. Routine care was delayed in 27% of hospitals evaluating patients for Ebola. LIMITATIONS Convenience sample of SHEA members with a moderate response rate. CONCLUSIONS Hospital Ebola preparations required extraordinary resources, which were diverted from routine infection prevention activities. Patients being evaluated for Ebola faced delays and potential limitations in management of other diseases that are more common in travelers returning from West Africa.

Effectiveness of an information technology intervention to improve prophylactic antibacterial use in the postoperative period

BACKGROUND A 2005 report from the Centers for Medicare and Medicaid Services and the Centers for Disease Control Surgical Infection Prevention program indicated that only 41% of prophylactic antibacterials were correctly stopped within 24 h of the end of surgery. Electronic order sets have shown promise as a means of integrating guideline information with electronic order entry systems and facilitating safer, more effective care. OBJECTIVE The aim was to study the effectiveness of a computer-based antibacterial order set on increasing the proportion of patients who have antibacterial wound prophylaxis discontinued in the appropriate time frame. DESIGN The authors conducted a quasi-experimental interrupted time-series analysis over an 8-month study period with the implementation of a computer-based order system designed to prevent excessive duration of surgical prophylaxis antibacterials. MEASUREMENT The primary outcome was the proportion of surgeries with antibacterials discontinued in the appropriate time frame. Additionally, we evaluated the percent of surgeries after implementation of the electronic intervention with chart documentation of infection among surgeries where the prescriber indicated the reason for antibacterial therapy was treatment. RESULTS The computer-based order intervention significantly improved the proportion of surgeries with timely discontinuation of antibacterials from 38.8% to 55.7% (p < 0.001) in the intervention hospital, while the control hospital remained at 56-57% (p = 0.006 for the difference between treated and control hospitals). In surgeries after intervention implementation where a prescriber indicated the reason for antibacterial therapy was treatment, the prevalence of chart documented infection was only 14%. CONCLUSIONS A computer-based electronic order set intervention increased timely discontinuation of postoperative antibacterials.