Brucellosis Initially Misidentified as Ochrobactrum anthropi Bacteremia: A Case Report and Review of the Literature.

Automated identification systems may misidentify Brucella, the causative agent of brucellosis, which may be re-emerging in the United States as the result of an expanding feral swine population. We present a case of Brucella suis likely associated with feral swine exposure that was misidentified as Ochrobactrum anthropi, a phylogenetic relative.

Clinical relevance of metronidazole and peripheral neuropathy: a systematic review of the literature.

The objective of this paper was to review and evaluate the literature on metronidazole-associated peripheral neuropathy and determine the relevance in clinical practice. MEDLINE/PubMed, EBSCO, and Google Scholar were searched through February 2017 using the search terms metronidazole and peripheral neuropathy, or polyneuropathy, or paresthesia, or neurotoxicity. Relevant case reports, retrospective studies, surveys, and review articles were included. Bibliographies of all relevant articles were reviewed for additional sources. Overall, metronidazole is generally well tolerated, but serious neurotoxicity, including peripheral neuropathy, has been reported. The overall incidence of peripheral neuropathy associated with metronidazole is unknown. Our review found 36 case reports (40 unique patients) of metronidazole-associated peripheral neuropathy, with most cases (31/40) receiving a >42 g total (>4 weeks) of therapy. In addition, we reviewed 13 clinical studies and found varying rates of peripheral neuropathy from 0 to 50%. Within these clinical studies, we found a higher incidence of peripheral neuropathy in patients receiving >42 g total (>4 weeks) of metronidazole compared with those patients receiving ≤42 g total (17.9% vs. 1.7%). Nearly all patients had complete resolution of symptoms. In conclusion, peripheral neuropathy is rare in patients who receive ≤42 g total of metronidazole. Patients who receive higher total doses may be at higher risk of peripheral neuropathy, but symptoms resolve after discontinuation of therapy in most patients. Antimicrobial stewardship programs may consider use of antibiotic combinations that include metronidazole over broad-spectrum alternatives when treating with ≤42 g total of the drug (≤4 weeks).

Decrease in Candida bloodstream infections in veterans in Atlanta.

Despite the recent focus on prevention of health care-associated infections, rates of Candida bloodstream infections in adults have remained unchanged until recently. We report a decline of Candida bloodstream infections, not explained by changes in broad-spectrum antibiotic use, but coinciding with infection control policies aimed at central venous catheter maintenance.

Antibiotic use in US hospitals: quantification, quality measures and stewardship.

A majority of patients hospitalized in the US hospitals receive an antibiotic during their hospitalization. Furthermore, up to half of antibiotics prescribed in hospitals are inappropriate. In the setting of continued emergence of antibiotic-resistant pathogens and a limited pipeline of new antimicrobials, attention to optimizing antibiotic use in healthcare settings is essential. We review the measures of antibiotic consumption in the USA, the evolving metrics for comparing antibiotic use (known as benchmarking), trends in antibiotic use, the structure and outcome measures of Antimicrobial Stewardship Programs and interventions to optimize antimicrobial use.

Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in residents of Veterans Affairs long-term care facilities: role of antimicrobial exposure and MRSA acquisition.

OBJECTIVE: To identify risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) acquisition in long-term care facility (LTCF) residents. DESIGN: Multicenter, prospective cohort followed over 6 months. SETTING: Three Veterans Affairs (VA) LTCFs. PARTICIPANTS: All current and new residents except those with short stay (<2 weeks). METHODS: MRSA carriage was assessed by serial nares cultures and classified into 3 groups: persistent (all cultures positive), intermittent (at least 1 but not all cultures positive), and noncarrier (no cultures positive). MRSA acquisition was defined by an initial negative culture followed by more than 2 positive cultures with no subsequent negative cultures. Epidemiologic data were collected to identify risk factors, and MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE). RESULTS: Among 412 residents at 3 LTCFs, overall MRSA prevalence was 58%, with similar distributions of carriage at all 3 facilities: 20% persistent, 39% intermittent, 41% noncarriers. Of 254 residents with an initial negative swab, 25 (10%) acquired MRSA over the 6 months; rates were similar at all 3 LTCFs, with no clusters evident. Multivariable analysis demonstrated that receipt of systemic antimicrobials during the study was the only significant risk factor for MRSA acquisition (odds ratio, 7.8 [95% confidence interval, 2.1-28.6]; P = .002). MRSA strains from acquisitions were related by PFGE to those from a roommate in 9/25 (36%) cases; 6 of these 9 roommate sources were persistent carriers. CONCLUSIONS: MRSA colonization prevalence was high at 3 separate VA LTCFs. MRSA acquisition was strongly associated with antimicrobial exposure. Roommate sources were often persistent carriers, but transmission from roommates accounted for only approximately one-third of MRSA acquisitions.

Emerging trends in antibiotic use in US hospitals: quality, quantification and stewardship.

Three major trends in antibiotic use in US hospitals have emerged over the last few years: antibiotics as quality metrics, persistent use of different measures of antibiotic consumption and the emergence of antibiotic stewardship programs. Compared with Europe, where approaches are heterogeneous but generally consistent, the USA currently lacks the infrastructure to monitor antibiotic resistance and antibiotic consumption locally. Both have implemented programmatic strategies for prudent antibiotic use. The USA appears to have implemented processes more systematically to measure the quality of antibiotic use.

Hospitalization earlier than 1 year prior to admission as an additional risk factor for methicillin-resistant Staphylococcus aureus colonization.

Our case-control study sought to identify risk factors for colonization with methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission among patients with no known healthcare-related risk factors. We found that patients whose most recent hospitalization occurred greater than 1 year before their current hospital admission were more likely to have MRSA colonization. In addition, both the time that elapsed since the most recent hospitalization and the duration of that hospitalization affected risk.

A multicenter study on optimizing piperacillin-tazobactam use: lessons on why interventions fail.

We examined interventions to optimize piperacillin-tazobactam use at 4 hospitals. Interventions for rotating house staff did not affect use. We could target empiric therapy in only 35% of cases. Because prescribing practices seemed to be institution specific, interventions should address attitudes of local prescribers. Interventions should target empiric therapy and ordering of appropriate cultures.

Measuring the scope and magnitude of hospital-associated infection in the United States: the value of prevalence surveys.

Health care-associated infections are a major public health concern both in the United States and abroad, contributing to increased morbidity, mortality, and health care costs. As a consequence of changes in health care delivery and increasing demands on infection prevention, targeted surveillance has become common in the United States, focusing on areas of the hospital where a patient's risk for health care-associated infection is greatest, as opposed to hospital-wide surveillance; the latter can be used to estimate the national burden of health care-associated infections. Many countries have shown that prevalence surveys can be used to quantify the burden of disease and to help establish priorities to accomplish national goals of prevention of health care-associated infection. Several different surveillance methods have been used, prohibiting comparisons of results among methods. We address some of these key differences and provide recommendations in areas that should be considered when designing a point prevalence survey in the United States.

Antimicrobial-associated risk factors for Clostridium difficile infection.

Antimicrobial therapy plays a central role in the pathogenesis of Clostridium difficile infection (CDI), presumably through disruption of indigenous intestinal microflora, thereby allowing C. difficile to grow and produce toxin. Investigations involving animal models and studies performed in vitro suggest that inhibitory activity against C. difficile and differences in the propensity to stimulate toxin production may also influence the likelihood that particular drugs may cause CDI. Although nearly all antimicrobial classes have been associated with CDI, clindamycin, third-generation cephalosporins, and penicillins have traditionally been considered to harbor the greatest risk. Recent studies have also implicated fluoroquinolones as high-risk agents, a finding that is most likely to be related in part to increasing fluoroquinolone resistance among epidemic strains (i.e., restriction-endonuclease analysis group BI/North American PFGE type 1 strains) and some nonepidemic strains of C. difficile. Restrictions in the use of clindamycin and third-generation cephalosporins have been associated with reductions in CDI. Because use of any antimicrobial has the potential to induce the onset of CDI and disease caused by other health care-associated pathogens, antimicrobial stewardship programs that promote judicious use of antimicrobials are encouraged in concert with environmental and infection control-related efforts.

Importance of bacterial burden among methicillin-resistant Staphylococcus aureus carriers in a long-term care facility.

OBJECTIVE: To evaluate the prevalence and transmission of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization, as well as risk factors associated with MRSA carriage, among residents of a long-term care facility (LTCF). DESIGN: Prospective, longitudinal cohort study. SETTING: A 100-bed Veterans Administration LTCF. PARTICIPANTS: All current and newly admitted residents of the LTCF during an 8-week study period. METHODS: Nasal swab samples were obtained weekly and cultured on MRSA-selective media, and the cultures were graded for growth on a semiquantitative scale from 0 (no growth) to 6 (heavy growth). Epidemiologic data for the periods before and during the study were collected to assess risk factors for MRSA carriage. RESULTS: Of 83 LTCF residents, 49 (59%) had 1 or more nasal swab cultures that were positive for MRSA; 34 (41%) were consistently culture-negative (designated "noncarriers"). Of the 49 culture-positive residents, 30 (36% of the total of 83 residents) had all cultures positive for MRSA (designated "persistent carriers"), and 19 (23% of the 83 residents) had at least 1 culture, but not all cultures, positive for MRSA (designated "intermittent carriers"). Multivariate analysis showed that participants with at least 1 nasal swab culture positive for MRSA were likely to have had previous hospitalization (odds ratio, 3.9) or wounds (odds ratio, 8.2). Persistent carriers and intermittent carriers did not differ in epidemiologic characteristics but did differ in mean MRSA growth score (3.7 vs 0.7; P<.001). CONCLUSIONS: Epidemiologic characteristics differed between noncarriers and subjects with at least 1 nasal swab culture positive for MRSA. However, in this LTCF population, only the degree of bacterial colonization (as reflected by mean MRSA growth score) distinguished persistent carriers from intermittent carriers. Understanding the burden of colonization may be important when determining future surveillance and control strategies.

Estimating health care-associated infections and deaths in U.S. hospitals, 2002.

OBJECTIVE: The purpose of this study was to provide a national estimate of the number of healthcare-associated infections (HAI) and deaths in United States hospitals. METHODS: No single source of nationally representative data on HAIs is currently available. The authors used a multi-step approach and three data sources. The main source of data was the National Nosocomial Infections Surveillance (NNIS) system, data from 1990-2002, conducted by the Centers for Disease Control and Prevention. Data from the National Hospital Discharge Survey (for 2002) and the American Hospital Association Survey (for 2000) were used to supplement NNIS data. The percentage of patients with an HAI whose death was determined to be caused or associated with the HAI from NNIS data was used to estimate the number of deaths. RESULTS: In 2002, the estimated number of HAIs in U.S. hospitals, adjusted to include federal facilities, was approximately 1.7 million: 33,269 HAIs among newborns in high-risk nurseries, 19,059 among newborns in well-baby nurseries, 417,946 among adults and children in ICUs, and 1,266,851 among adults and children outside of ICUs. The estimated deaths associated with HAIs in U.S. hospitals were 98,987: of these, 35,967 were for pneumonia, 30,665 for bloodstream infections, 13,088 for urinary tract infections, 8,205 for surgical site infections, and 11,062 for infections of other sites. CONCLUSION: HAIs in hospitals are a significant cause of morbidity and mortality in the United States. The method described for estimating the number of HAIs makes the best use of existing data at the national level.

Knowledge, attitudes, and behaviors regarding piperacillin-tazobactam prescribing practices: results from a multicenter study.

We investigated knowledge, attitudes, and behaviors of prescribers concerning piperacillin-tazobactam use at 4 Emory University-affiliated hospitals. Discussions during focus groups indicated that the participants' perceived knowledge of clinical criteria for appropriate piperacillin-tazobactam use was inadequate. Retrospective review of medical records identified inappropriate practices. These findings have influenced ongoing interventions aimed at optimizing piperacillin-tazobactam use.

Monitoring patient safety in health care: building the case for surrogate measures.

BACKGROUND: Objective measurements are notably lacking for many adverse events in health care. A new approach to monitoring such events is based on the experience in measuring hospital-associated infections. DEVELOPING OBJECTIVE AND UNIVERSAL MEASURES: An essential tenet of the current goal of surveillance-focusing only on rigorously confirmed adverse events-is neither necessary nor achievable across the entire health care system. Efforts should be directed instead to creating objective measures of quality of care and of outcomes that can be used by all health care facilities. Adopting objective measures would be easier if health care was open to surrogate measures of important outcomes. Surrogate measures of interest for infection surveillance are used to identify objective, readily ascertained events that are sufficiently correlated with infections to provide useful information about organizations' infection rates. For example, the surgical site infection rate following coronary artery bypass appears to correlate closely enough with the proportion of patients who receive extended courses of inpatient antibiotics to be a useful indicator of a hospital's outcomes for the procedure. CONCLUSION: Developing clinically relevant process or surrogate measures that clinicians would use to improve patient outcomes is essential. These measures could be relevant not only to hospital-acquired infections but other health care-related adverse events that are relatively common yet require substantial resources to identify.

Comparing bloodstream infection rates: the effect of indicator specifications in the evaluation of processes and indicators in infection control (EPIC) study.

OBJECTIVE: Bloodstream infection (BSI) rates are used as comparative clinical performance indicators; however, variations in definitions and data-collection approaches make it difficult to compare and interpret rates. To determine the extent to which variation in indicator specifications affected infection rates and hospital performance rankings, we compared absolute rates and relative rankings of hospitals across 5 BSI indicators. DESIGN: Multicenter observational study. BSI rate specifications varied by data source (clinical data, administrative data, or both), scope (hospital wide or intensive care unit specific), and inclusion/exclusion criteria. As appropriate, hospital-specific infection rates and rankings were calculated by processing data from each site according to 2-5 different specifications. SETTING: A total of 28 hospitals participating in the EPIC study. PARTICIPANTS: Hospitals submitted deidentified information about all patients with BSIs from January through September 1999. RESULTS: Median BSI rates for 2 indicators based on intensive care unit surveillance data ranged from 2.23 to 2.91 BSIs per 1000 central-line days. In contrast, median rates for indicators based on administrative data varied from 0.046 to 7.03 BSIs per 100 patients. Hospital-specific rates and rankings varied substantially as different specifications were applied; the rates of 8 of 10 hospitals were both greater than and less than the mean. Correlations of hospital rankings among indicator pairs were generally low (rs=0-0.45), except when both indicators were based on intensive care unit surveillance (rs = 0.83). CONCLUSIONS: Although BSI rates seem to be a logical indicator of clinical performance, the use of various indicator specifications can produce remarkably different judgments of absolute and relative performance for a given hospital. Recent national initiatives continue to mix methods for specifying BSI rates; this practice is likely to limit the usefulness of such information for comparing and improving performance.

Detection of postoperative surgical-site infections: comparison of health plan-based surveillance with hospital-based programs.

BACKGROUND: Review of health plan administrative data has been shown to be more sensitive than other methods for identifying postdischarge surgical-site infections (SSIs), but there has not been a direct comparison between this method and hospital-based surveillance for all infections, including those diagnosed before discharge. We compared these two methods for identifying SSIs following coronary artery bypass graft (CABG) procedures. METHODS: We studied 1,352 CABG procedures performed among members of one health plan from March 1993 through June 1997. Health plan administrative records were reviewed based on claims containing diagnoses or procedures suggestive of infection or outpatient dispensing of antibiotics appropriate for SSI. Hospital-based surveillance information was also reviewed. SSI rates were calculated based on the total events identified by either mechanism. RESULTS: Postdischarge information was reviewed for 328 (85%) of 388 procedures. SSIs were confirmed in 167 patients (13% overall risk of confirmed SSI; range, 3% to 14% in the 5 hospitals). The overall sensitivity of hospital-based surveillance was 49.7% (83 of 167), and that of health plan data was 71.8% (120 of 167). There was no significant difference among hospitals in the sensitivity of either surveillance mechanism. CONCLUSIONS: Surveillance based on health plan data identified more postoperative infections, including those occurring before discharge, than did hospital-based surveillance. Screening administrative data and pharmacy activity may be an important adjunct to SSI surveillance, allowing efficient comparison of hospital-specific rates. Interpretation of differences among hospitals' infection rates requires case mix adjustment and understanding of variations in hospitals' discharge diagnosis coding practices.

Antimicrobial proficiency testing of National Nosocomial Infections Surveillance System hospital laboratories.

OBJECTIVE: The National Nosocomial Infections Surveillance (NNIS) System personnel report trends in antimicrobial-resistant pathogens. To validate select antimicrobial susceptibility testing results and to identify test methods that tend to produce errors, we conducted proficiency testing among NNIS System hospital laboratories. SETTING: NNIS System hospital laboratories in the United States. METHODS: Each laboratory received five organisms (ie, an imipenem-resistant Serratia marcescens, an oxacillin-resistant Staphylococcus aureus, a vancomycin-resistant Enterococcus faecalis, a vancomycin-intermediate Staphylococcus epidermidis, and an extended-spectrum beta-lactamase (ESbetaL)-producing Klebsiella pneumoniae). Testing results were compared with reference testing results from the Centers for Disease Control and Prevention. RESULTS: Of 138 laboratories testing imipenem against the Serratia marcescens strain, 110 (80%) correctly reported minimum inhibitory concentrations (MICs) or zone sizes in the resistant range. All 193 participating laboratories correctly reported the Staphylococcus aureus strain as oxacillin resistant Of the 193 laboratories, 169 (88%) reported correct MICs or zone sizes for the vancomycin-resistant Enterococcus faecalis. One hundred sixty-two (84%) of 193 laboratories demonstrated the ability to detect a vancomycin-intermediate strain of Staphylococcus epidermidis, however, disk diffusion performed poorly when testing both staphylococci and enterococci with vancomycin. Although laboratory personnel correctly reported nonsusceptible extended-spectrum cephalosporins and aztreonam results for K. pneumoniae, only 98 (51%) of 193 correctly reported this organism as an ESbetaL producer. CONCLUSION: Overall, NNIS System hospital laboratory personnel detected most emerging resistance patterns. Disk diffusion continues to be unreliable for vancomycin testing of staphylococci and must be used cautiously for enterococci. Further education on the processing of ESbetaL-producing organisms is warranted.

Antimicrobial susceptibility testing of carbapenems: multicenter validity testing and accuracy levels of five antimicrobial test methods for detecting resistance in Enterobacteriaceae and Pseudomonas aeruginosa isolates.

From January 1996 to May 1999, Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology) received 448 nonduplicate clinical isolates of Enterobacteriaceae and Pseudomonas aeruginosa that were reported to be imipenem intermediate or resistant. However, broth microdilution (BMD) confirmatory testing at the Project ICARE central laboratory confirmed this result in only 11 of 123 (8.9%) Enterobacteriaceae isolates and 241 of 325 (74.2%) P. aeruginosa isolates. To investigate this overdetection of imipenem resistance, we tested 204 selected isolates from the Project ICARE collection plus five imipenem-resistant challenge strains at the Centers for Disease Control and Prevention against imipenem and meropenem by agar dilution, disk diffusion, Etest (AB BIODISK North America, Inc., Piscataway, N.J.), two MicroScan WalkAway conventional panels (Neg MIC Plus 3 and Neg Urine Combo 3) (Dade MicroScan, Inc., West Sacramento, Calif.), and two Vitek cards (GNS-116 containing meropenem and GNS-F7 containing imipenem) (bioMérieux Vitek, Inc., Durham, N.C.). The results of each test method were compared to the results of BMD testing using in-house-prepared panels. Seven imipenem-resistant and five meropenem-resistant isolates of Enterobacteriaceae and 43 imipenem-resistant and 21 meropenem-resistant isolates of P. aeruginosa were identified by BMD. For Enterobacteriaceae, the imipenem and meropenem test methods produced low numbers of very major and major errors. All test systems in the study produced low numbers of very major and major errors when P. aeruginosa was tested against imipenem and meropenem, except for Vitek testing (major error rate for imipenem, 20%). Further testing conducted in 11 of the participating ICARE hospital laboratories failed to pinpoint the factors responsible for the initial overdetection of imipenem resistance. However, this study demonstrated that carbapenem testing difficulties do exist and that laboratories should consider using a second, independent antimicrobial susceptibility testing method to validate carbapenem-intermediate and -resistant results.