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Biomedical subjects

Daniel J Diekema

Publications and source records attributed to Daniel J Diekema.

At least 19 recordsLinked to original sources
PubMed2006

Improving methicillin-resistant Staphylococcus aureus surveillance and reporting in intensive care units.

BACKGROUND: Routine culturing of patients in intensive care units (ICUs) for methicillin-resistant Staphylococcus aureus (MRSA) identifies unrecognized carriers and facilitates timely isolation. However, the benefit of surveillance in detecting prevalent and incident carriers likely varies among ICUs. In addition, many assessments underestimate the incidence of acquisition by including prevalent carriers in the at-risk population. METHODS: We performed a retrospective cohort study using accurate at-risk populations to evaluate the range of benefit of admission and weekly surveillance cultures in detecting otherwise unrecognized MRSA in 12 ICUs in 5 states. RESULTS: We assessed 142 ICU-months. Among the 12 ICUs, the admission prevalence of imported MRSA was 5%-21%, with admission surveillance providing 30%-135% increases in rates of detection. The monthly hospital-associated incidence was 2%-6%, with weekly surveillance providing 7%-157% increases in detection. The common practice of reporting incidence using the total number of patients or total patient-days underestimated incidence by one-third. Surgical ICUs had lower MRSA importation but higher MRSA incidence. Overall, routine surveillance prevented the misclassification of 17% (unit range, 11%-29%) of "incident" carriers, compared with clinical cultures, and increased precaution days by 18% (unit range, 11%-91%). CONCLUSIONS: Routine surveillance significantly increases the detection of MRSA, but this benefit is not uniform across ICUs, even with high compliance and the use of correct denominators.

Academic Medical Centers↗
PubMed2006

Improving the assessment of vancomycin-resistant enterococci by routine screening.

BACKGROUND: As infection with vancomycin-resistant enterococci (VRE) increases in hospitals, knowledge about VRE reservoirs and improved accuracy of epidemiologic measures are needed. Many assessments underestimate incidence by including prevalent carriers in at-risk populations. Routine surveillance cultures can substantially improve prevalence and incidence estimates, and assessing the range of improvement across diverse units is important. METHODS: We performed a retrospective cohort study using accurate at-risk populations to evaluate the range of benefit of admission and weekly surveillance cultures in detecting unrecognized VRE in 14 patient-care units. RESULTS: We assessed 165 unit-months. The admission prevalence of VRE was 2.2%-27.2%, with admission surveillance providing 2.2-17-fold increased detection. Medical units were significantly more likely to admit VRE carriers than were surgical units. Monthly incidence was 0.8%-9.7%, with weekly surveillance providing 3.3-15.4-fold increased detection. The common practice of reporting incidence using the total number of patients, rather than patients at risk, underestimated incidence by one-third. Overall, routine surveillance prevented the misclassification of 43.0% (unit range, 0%-85.7%) of "incident" carriers on the basis of clinical cultures alone and increased VRE precaution days by 2.4-fold (unit range, 2.0-2.6-fold). CONCLUSIONS: Routine surveillance markedly increases the detection of VRE, despite variability across patient-care units. Correct denominators prevent the substantial underestimation of incidence.

Academic Medical Centers↗
PubMed2006

Antimicrobial use control measures to prevent and control antimicrobial resistance in US hospitals.

OBJECTIVE: Clinical practice guidelines and recommended practices to control use of antibiotics have been published, but the effect of these practices on antimicrobial resistance (AMR) rates in hospitals is unknown. The objective of this study was to examine relationships between antimicrobial use control strategies and AMR rates in a national sample of US hospitals. DESIGN: Cross-sectional, stratified study of a nationally representative sample of US hospitals. METHODS: A survey instrument was sent to the person responsible for infection control at a sample of 670 US hospitals. The outcome was current prevalences of 4 epidemiologically important, drug-resistant pathogens, considered concurrently: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, ceftazidime-resistant Klebsiella species, and quinolone (ciprofloxacin)-resistant Escherichia coli. Five independent variables regarding hospital practices were selected from the survey: the extent to which hospitals (1) implement practices recommended in clinical practice guidelines and ensure best practices for antimicrobial use, (2) disseminate information on clinical practice guidelines for antimicrobial use, (3) use antimicrobial-related information technology, (4) use decision support tools, and (5) communicate to prescribers about antimicrobial use. Control variables included the hospitals' number of beds, teaching status, Veterans Affairs status, geographic region, and number of long-term care beds; and the presence of an intensive care unit, a burn unit, or transplant services. A generalized estimating equation modeled all resistance rates simultaneously to identify overall predictors of AMR levels at the facility. RESULTS: Completed survey instruments were returned by 448 hospitals (67%). Four antimicrobial control measures were associated with higher prevalence of AMR. Implementation of recommended practices for antimicrobial use (P < .01) and optimization of the duration of empirical antibiotic prophylaxis (P < .01) were associated with a lower prevalence of AMR. Use of restrictive formularies (P = .05) and dissemination of clinical practice guideline information (P < .01) were associated with higher prevalence of AMR. Number of beds and Veterans Affairs status were also associated with higher AMR rates overall. CONCLUSIONS: Implementation of guideline-recommended practices to control antimicrobial use and optimize the duration of empirical therapy appears to help control AMR rates in US hospitals. A longitudinal study would confirm the results of this cross-sectional study. These results highlight the need for systems interventions and reengineering to ensure more-consistent application of guideline-recommended measures for antimicrobial use.

Anti-Bacterial Agents↗
PubMed2006

Descriptive epidemiology and case-control study of patients colonized with vancomycin-resistant enterococcus and methicillin-resistant Staphylococcus aureus.

BACKGROUND: Patients colonized or infected with vancomycin-resistant enterococcus and methicillin-resistant Staphylococcus aureus may be at risk of acquiring vancomycin-resistant S. aureus if the vanA gene is transferred from vancomycin-resistant enterococcus to methicillin-resistant S. aureus. OBJECTIVE: Our goal was to identify risk factors for cocolonization or coinfection (CC/CI) with vancomycin-resistant enterococcus and methicillin-resistant S. aureus. DESIGN: We conducted a descriptive, epidemiologic study of all patients with CC/CI identified from January 1998 to May 2003 and a nested case-control study of a cohort of patients hospitalized in the burn and wound unit. SETTING: We conducted our study in a 813-bed tertiary care university teaching hospital. POPULATION: The study population consisted of patients found to have CC/CI during the study period. METHODS: Descriptive epidemiologic data were collected from hospital records of all patients identified as having CC/CI. A subset of patients hospitalized in the burn and wound unit were included in a case-control study. RESULTS: CC/CI was detected in 71% of the patients during a single hospital stay. The burn and wound unit, which does active surveillance for both organisms, and the general medicine unit, which does not do active surveillance for either organism, cared for more than one-half of these patients. Among patients being cared for in the burn and wound unit, having exposure to 2 or more invasive devices (central venous catheters, indwelling urinary catheters, and enteral feeding tubes) and renal insufficiency were independent risk factors for CC/CI. CONCLUSIONS: Patients with CC/CI are the population at greatest risk for vancomycin-resistant S. aureus colonization or infection. The number of invasive devices to which patients are exposed and, thus, possibly the patients' underlying severity of illness, as well as renal insufficiency, appear to be risk factors for CC/CI.

Adult↗
PubMed2006

A multicenter intervention to prevent catheter-associated bloodstream infections.

BACKGROUND: Education-based interventions can reduce the incidence of catheter-associated bloodstream infection. The generalizability of findings from single-center studies is limited. OBJECTIVE: To assess the effect of a multicenter intervention to prevent catheter-associated bloodstream infections. DESIGN: An observational study with a planned intervention. SETTING: Twelve intensive care units and 1 bone marrow transplantation unit at 6 academic medical centers. PATIENTS: Patients admitted during the study period. INTERVENTION: Updates of written policies, distribution of a 9-page self-study module with accompanying pretest and posttest, didactic lectures, and incorporation into practice of evidence-based guidelines regarding central venous catheter (CVC) insertion and care. MEASUREMENTS: Standard data collection tools and definitions were used to measure the process of care (ie, the proportion of nontunneled catheters inserted into the femoral vein and the condition of the CVC insertion site dressing for both tunneled and nontunneled catheters) and the incidence of catheter-associated bloodstream infection. RESULTS: Between the preintervention period and the postintervention period, the percentage of CVCs inserted into the femoral vein decreased from 12.9% to 9.4% (relative ratio, 0.73; 95% confidence interval [CI], 0.61-0.88); the total proportion of catheter insertion site dressings properly dated increased from 26.6% to 34.4% (relative ratio, 1.29; 95% CI, 1.17-1.42), and the overall rate of catheter-associated bloodstream infections decreased from 11.2 to 8.9 infections per 1,000 catheter-days (relative rate, 0.79; 95% CI, 0.67-0.93). The effect of the intervention varied among individual units. CONCLUSIONS: An education-based intervention that uses evidence-based practices can be successfully implemented in a diverse group of medical and surgical units and reduce catheter-associated bloodstream infection rates.

Academic Medical Centers↗
PubMed2006

Incidence of invasive aspergillosis among allogeneic hematopoietic stem cell transplant patients receiving voriconazole prophylaxis.

We performed a retrospective observational study to examine the incidence of invasive aspergillosis (IA) among allogeneic hematopoietic stem cell transplant (HSCT) recipients, according to whether patients received at least 1 week of voriconazole prophylaxis. We report no cases of IA among 92 HSCT recipients who received voriconazole prophylaxis compared with a 10% (23/223) incidence among those receiving other systemic antifungals for prophylaxis (P < .0005).

Adult↗
PubMed2006

Epidemiology of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in a rural state.

BACKGROUND: Most data on methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) isolates come from large tertiary care centers. Infection control personnel need to understand the epidemiology of MRSA and VRE across the continuum of care, including small rural hospitals, to develop effective control strategies. OBJECTIVE: To describe the epidemiology of MRSA and VRE in Iowa. SETTING: Fifteen hospitals in Iowa. Methods Between July 1998 and June 2001, a total of 1,968 S. aureus isolates and 1,845 Enterococcus isolates from patients infected with these pathogens were examined. Multivariate models were developed to evaluate patient and institutional risk factors for MRSA infection and VRE infection. RESULTS: The proportion of S. aureus isolates resistant to methicillin was 31%, and the proportion of Enterococcus isolates resistant to vancomycin was 6%. Independent risk factors for MRSA infection included residence in a long-term care facility, age of more than 60 years, hospitalization in a hospital with less than 200 short-term care beds, and acquiring the infection in the hospital. Independent risk factors for VRE infection included use of a central venous catheter, residence in a long-term care facility, acquisition of infection in the hospital, and hospitalization in a hospital with more than 200 short-term care beds. CONCLUSIONS: In Iowa, the epidemiology of MRSA differ from those of VRE. MRSA has become established in small rural hospitals. Effective MRSA control strategies may require inclusion of all hospitals in a state or region.

Aged↗
PubMed2006

Risk factors for groin wound infection after femoral artery catheterization: a case-control study.

OBJECTIVE: Groin wound infection (GWI) after femoral artery catheterization is unusual. However, several reports of GWI associated with the use of a Perclose device appear in the surgical literature. DESIGN: A case-control study. SETTING: We pooled 23 cases and 83 controls from a university hospital and a community medical center. PATIENTS: A case was defined as a patient who developed a GWI after a femoral artery catheterization. At the university hospital, 3 controls were randomly selected from the at-risk population and matched to each case by time of procedure only (within 2 weeks). At the community medical center, 4 controls were selected and matched to each case by time of procedure (within 2 weeks), sex, and age (within 5 years). RESULTS: We considered several covariates, including age, sex, body mass index, medical conditions, Perclose use, hematoma formation, and antithrombotic therapy. In a multivariate model, only hematoma formation (odds ratio, 68.8; 95% confidence interval, 12.1-391.4) and glycoprotein IIb/IIIa platelet inhibitor therapy (odds ratio, 6.1; 95% confidence interval, 1.1-33.6) were statistically significant predictors of GWI; Perclose use (odds ratio, 0.9; 95% confidence interval, 0.2-3.7) was not a statistically significant predictor of GWI. However, most of the hematomas (15/17) formed after procedures during which a Perclose device was used. CONCLUSION: Perclose use did not have any additional effect on GWI risk beyond the effect that hematoma formation had.

Case-Control Studies↗
PubMed2006

A case of recurrent episodes of Candida parapsilosis fungemia.

Candida species is the fourth most commonly isolated organism in blood stream infections in the hospital setting. Patients with candidemia frequently succumb to this infection. For those that survive an initial candidemia, an increasing number of cases of breakthrough or recurrent candidemias have been reported in the literature. We report three episodes of C. parapsilosis fungemia in a cancer patient. Molecular testing was performed and confirmed that all these episodes occurring within an eight-month period were caused by the same organism. The incidence of recurrent candidemia is likely to increase in the near future. Studies and therapeutic interventions for patients at risk for recurrent candidemias are warranted.

Adenocarcinoma↗
PubMed2005

Implementation of strategies to prevent and control the emergence and spread of antimicrobial-resistant microorganisms in U.S. hospitals.

OBJECTIVE: To examine the extent to which the strategies recommended by the National Foundation for Infectious Diseases (NFID)-Centers for Disease Control and Prevention (CDC) co-sponsored workshop, Antimicrobial Resistance in Hospitals: Strategies to Improve Antimicrobial Use and Prevent Nosocomial Transmission of Antimicrobial-Resistant Microorganisms, have been implemented and the relationship between the degree of implementation and hospital culture, leadership, and organizational factors. DESIGN: Survey. SETTING: A representative sample of U.S. hospitals stratified by teaching status, bed size, and geographic region. PARTICIPANTS: Infection control professionals. RESULTS: Surveyed hospitals had implemented strategies to optimize the use of antimicrobials and to detect, report, and prevent transmission of antimicrobial-resistant microorganisms. Multivariate analyses found that hospitals with a greater degree of implementation of the NFID-CDC strategic goals were more likely to have management support, education of staff, and interdisciplinary groups specifically to address these issues; they were also more likely to engage in benchmarking on broader quality of care indicators. CONCLUSIONS: Most surveyed hospitals had implemented some measures to address the NFID-CDC recommendations; however, hospitals need to do much more to improve antimicrobial use and to increase their efforts to detect, report, and control the spread of antimicrobial resistance. A supportive hospital administration must foster a culture of ongoing support, education, and interdisciplinary work groups focused on this important issue to successfully accomplish these goals.

Analysis of Variance↗
PubMed2005

Variation in the use of procedures to monitor antimicrobial resistance in U.S. hospitals.

BACKGROUND: Antimicrobial resistance is a growing clinical and public health crisis. Experts have recommended measures to monitor antimicrobial resistance; however, little is known regarding their use. OBJECTIVE: We describe the use of procedures to detect and report antimicrobial resistance in U.S. hospitals and the organizational and epidemiologic factors associated with their use. METHODS: In 2001, we surveyed laboratory directors (n = 108) from a random national sample of hospitals. We studied five procedures to monitor antimicrobial resistance: (1) disseminating antibiograms to physicians at least annually, (2) notifying physicians of antimicrobial-resistant infections, (3) reporting susceptibility results within 24 hours, (4) using automated testing procedures, and (5) offering molecular typing. Explanatory variables included organizational characteristics and patterns of antimicrobial resistance for oxacillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, quinolone-resistant Escherichia coli, and extended-spectrum beta-lactamase-producing Klebsiella species. Generalized estimating equations accounting for the correlation among outcomes at the facility level were used to identify predictors of the five outcomes. RESULTS: Use of the procedures ranged from 85% (automated testing) to 33% (offering molecular typing) and was related to teaching hospital status (OR, 3.1; CI95, 1.5-6.5), participation of laboratory directors on the infection control committee (OR, 1.7; CI95, 1.1-2.8), and having at least one antimicrobial-resistant pathogen with a prevalence greater than 10% (OR, 2.2; CI95, 1.4-3.3). CONCLUSION: U.S. hospitals underutilize procedures to monitor the spread of antimicrobial resistance. Use of these procedures varies and is related to organizational and epidemiologic factors. Further efforts are needed to increase their use by hospitals.

Cross Infection↗
PubMed2005

Determining the clinical significance of coagulase-negative staphylococci isolated from blood cultures.

BACKGROUND AND OBJECTIVE: Coagulase-negative staphylococci are both an important cause of nosocomial blood-stream infections and the most common contaminants of blood cultures. Judging the clinical significance of coagulase-negative staphylococci is vital but often difficult and can have a profound impact on an institution's bloodstream infection rates. Our objective was to develop an algorithm to assist in determining the clinical significance of coagulase-negative staphylococci. DESIGN: A single experienced reviewer examined the medical records of 960 consecutive patients with positive blood cultures in a tertiary-care referral teaching hospital. Four hundred five of the cultures contained coagulase-negative staphylococci. A determination of clinical significance was made and the performances of various published algorithms that contained readily available clinical and laboratory data were compared. RESULTS: Eighty-nine (22%) of the episodes were considered significant, whereas 316 were contaminants. Patients with bacteremia were significantly more likely to be neutropenic and exhibit signs of sepsis syndrome. The algorithm with the best combined sensitivity (62%) and specificity (91%) for determining the clinical significance of coagulase-negative staphylococci was defined as at least two blood cultures positive for coagulase-negative staphylococci within 5 days, or one positive blood culture plus clinical evidence of infection, which includes abnormal white blood cell count and temperature or blood pressure. CONCLUSION: Use of this algorithm could potentially reduce misclassification of nosocomial bloodstream infections and inappropriate use of vancomycin for positive blood cultures likely to represent contamination.

Algorithms↗
PubMed2005

Importance of control group selection for evaluating antimicrobial use as a risk factor for methicillin-resistant Staphylococcus aureus bacteremia.

OBJECTIVE: We investigated the importance of control group selection during an evaluation of antimicrobial use as a risk factor for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia at our institution. METHODS: We performed a case-control study. A case was defined as any patient admitted between January 1997 and May 2001 who developed nosocomial MRSA bacteremia. We used two control groups; control group I consisted of patients with nosocomial methicillin-susceptible S. aureus (MSSA) bacteremia and control group II included only patients without bacteremia. We matched control-patients to case-patients using age, gender, time at risk, and hospital ward. Data collected on all patients included demographics, comorbidities, antibiotic use, time at risk, length of stay, severity of illness, and outcome. RESULTS: We evaluated 63 patients (21 in each group). The three groups were well matched regarding age, gender, underlying diseases, and severity of illness. Patients in the MRSA group were more likely to have received a fluoroquinolone and had a higher mean number of days of fluoroquinolone use than did patients in the MSSA group (P = .027 and P = .015, respectively). However, all measures of fluoroquinolone use were similar for case-patients and for control-patients who did not have nosocomial bloodstream infection. CONCLUSIONS: Control group selection is important in evaluating antimicrobial use as a risk factor for MRSA bacteremia. Using control-patients infected with MSSA, rather than uninfected control-patients, may overestimate the association between antimicrobial use and MRSA infection.

Anti-Bacterial Agents↗
PubMed2005

Antifungal susceptibilities of Candida species causing vulvovaginitis and epidemiology of recurrent cases.

There are limited data regarding the antifungal susceptibility of yeast causing vulvovaginal candidiasis, since cultures are rarely performed. Susceptibility testing was performed on vaginal yeast isolates collected from January 1998 to March 2001 from 429 patients with suspected vulvovaginal candidiasis. The charts of 84 patients with multiple positive cultures were reviewed. The 593 yeast isolates were Candida albicans (n = 420), Candida glabrata (n = 112), Candida parapsilosis (n = 30), Candida krusei (n = 12), Saccharomyces cerevisiae ( n = 9), Candida tropicalis (n = 8), Candida lusitaniae (n = 1), and Trichosporon sp. (n = 1). Multiple species suggesting mixed infection were isolated from 27 cultures. Resistance to fluconazole and flucytosine was observed infrequently (3.7% and 3.0%); 16.2% of isolates were resistant to itraconazole (MIC > or = 1 microg/ml). The four imidazoles (econazole, clotrimazole, miconazole, and ketoconazole) were active: 94.3 to 98.5% were susceptible at < or =1 microg/ml. Among different species, elevated fluconazole MICs (> or = 16 microg/ml) were only observed in C. glabrata (15.2% resistant [R], 51.8% susceptible-dose dependent [S-DD]), C. parapsilosis (3.3% S-DD), S. cerevisiae (11.1% S-DD), and C. krusei (50% S-DD, 41.7% R, considered intrinsically fluconazole resistant). Resistance to itraconazole was observed among C. glabrata (74.1%), C. krusei (58.3%), S. cerevisiae (55.6%), and C. parapsilosis (3.4%). Among 84 patients with recurrent episodes, non-albicans species were more common (42% versus 20%). A > or = 4-fold rise in fluconazole MIC was observed in only one patient with C. parapsilosis. These results support the use of azoles for empirical therapy of uncomplicated candidal vulvovaginitis. Recurrent episodes are more often caused by non-albicans species, for which azole agents are less likely to be effective.

Antifungal Agents↗
PubMed2004

Invasive zygomycosis in hematopoietic stem cell transplant recipients receiving voriconazole prophylaxis.

We report 4 cases of invasive zygomycosis in hematopoietic stem cell transplant recipients, all occurring after May 2003, when voriconazole began to be used as antifungal prophylaxis. No cases of zygomycosis had been detected in this population in the 3 years prior to May 2003. All 4 patients were receiving immunosuppressive therapy for presumed graft-versus-host disease. Profoundly immunosuppressed patients receiving voriconazole prophylaxis remain at risk for less-common pathogens that are intrinsically resistant to this agent.

Adult↗
PubMed2004

Are United States hospitals following national guidelines for the analysis and presentation of cumulative antimicrobial susceptibility data?

The National Committee for Clinical Laboratory Standards recently published guidelines for analysis and presentation of cumulative antimicrobial susceptibility test data (antibiograms). We sought to determine how well US hospitals already adhere to standards for antibiogram compilation, and to examine the relationship between hospital characteristics and guideline adherence. We surveyed laboratory directors at 670 hospitals and examined 3 guideline criteria: compilation of an antibiogram, annual updating, and distribution to infection control staff and medical staff yearly; 494 surveys were returned (74%). Almost all of the hospitals surveyed publish an antibiogram (95%, n = 481); however, only 60% (n = 296) met all three criteria. Hospital laboratories meeting criteria were more likely to serve as referral laboratories (OR = 1.82; 95% CI = 1.26-2.63), perform susceptibility testing on site (OR = 4.47; 95% CI = 1.84-10.84), use confirmatory tests to detect extended-spectrum beta-lactamases (OR = 1.8; 95% CI = 1.2-2.6), and have more laboratory personnel per bed (3.0 vs. 2.0 FTEs/bed, p = 0.0031). Adherence to guidelines for preparation and dissemination of antibiograms could be improved. Institutional commitment to high quality, on-site microbiology laboratory services will improve adherence to these guidelines.

Anti-Bacterial Agents↗