Rate Of Antimicrobial Use Research Articles

Effectiveness of antimicrobial treatment of salmonid rickettsial septicaemia in commercial salmon and trout farms in Chile

Salmonid rickettsial septicaemia (SRS) is the most important disease of farmed salmonid fish in Chile and the main driver of a high rate of antimicrobial use. This study evaluated the effectiveness of antimicrobial treatment of SRS outbreaks, using industry-generated data from 8318 cage-level production cycles stocked between 2003 and 2018. We defined SRS outbreaks by a specified level of SRS-attributed mortality over a 3-week period and calculated the mortality rate attributed to SRS and unknown causes during a follow-up period from the start of treatment until resolution of the outbreak. The post-treatment mortality rate was used as a proxy for assessing the effectiveness of the antimicrobial treatment on the magnitude of the SRS outbreak. After developing a causal diagram, we analyzed the data with generalized, mixed-effects regression models within an information-theoretic framework. For producers of Atlantic salmon, our results suggest that treatment should be provided to all infected cages on the farm, without interruption, as soon as possible after the start of the SRS outbreak. For producers of rainbow trout, our results suggest that treatment should be initiated as early as possible after the start of the SRS outbreak and with longer treatment durations if using in-feed florfenicol treatments. In the rainbow trout model, the large proportion of unexplained variance at the company and farm level indicates that lessons can be learned from the experience of other companies and farms. This study demonstrates the value of integrating aquaculture industry-generated health and management data to support applied epidemiological research.

1014. Decreasing Antimicrobial Use by 25% via Submission to NHSN-AUR Module

BackgroundTracking antimicrobial data are a core element of antimicrobial stewardship programs. Since 2014, the Washington State Health Association (WSHA) has tracked antimicrobial use (AU) to address and reduce C. difficile infections statewide. In 2016, WA state began promoting the National Healthcare Safety Network (NHSN) tool to upload hospital AU. Both track days of antimicrobial therapy (DOT) but WSHA uses patient-days as the denominator while NHSN uses days-present. Each measure accounts for hospital length of stay but the latter is affected by unit transfers and the former is not.MethodsObservational review of AU data submitted to NHSN and to WSHA in a 2-year period. Sixteen antibiotics selected by WSHA were reviewed and organized into 5 groups: broad-spectrum penicillins, cephalosporins, carbapenems, fluoroquinolones, and clindamycin. Data from a single center were used to compare results between each AU tracker. AU and days-present were obtained from the electronic medical record. Patient-days were obtained from the hospital quality department. The primary outcome was a difference in AU per WSHA vs. NHSN.ResultsBetween January 2017 to December 2018, the median rate of antimicrobial use was 279 days per 1000 patient-days and 201 days per 1000 days-present. The median difference in total AU reported was 25% less using NHSN vs. WSHA and ranged from 18% - 31%.ConclusionSwitching from patient-days to days-present decreased the reported rate of AU by 25%. In WA state, hospitals have nonuniformly adopted submitting antimicrobial use data to the NHSN. Until all hospitals submit their data via NHSN, both individual institutions and the state will have to contend with mismatched data. An interim solution may be to collect monthly patient-days and days-present from all hospitals and adjust the data before comparing AU among institutions. For institutions with a long history of tracking antimicrobial use, this change in denominator and resulting impact on AU represents a barrier to using the NHSN AU module. Disclosures All authors: No reported disclosures.

Social norm feedback reduces primary care antibiotic prescribing in a regression discontinuity study.

Reducing antibiotic prescribing is a priority for health authorities responsible for preventing antimicrobial resistance. Northern Ireland has high rates of antimicrobial use. We implemented a social norm feedback intervention and evaluated its impact. To estimate the size and duration of the effect of a social norm feedback letter to GPs who worked in the 20% of practices with the highest antimicrobial prescribing. The letter was sent in October 2017 to 221 GPs in 67 practices. To assess the effect of the intervention, we used a sharp non-parametric regression discontinuity (RD) design, with prescribing rates in the four calendar quarters following the intervention as the outcome variables. In the quarter following the intervention (October to December 2017) there was a change of -25.7 (95% CI = -42.5 to -8.8, P = 0.0028) antibiotic items per 1000 Specific Therapeutic group Age-sex Related Prescribing Units (STAR-PU). At 1 year, the coefficient was -58.7 (95% CI = -116.7 to -0.7, P = 0.047) antibiotic items per 1000 STAR-PU. The greatest change occurred soon after the intervention. Approximately 18900 fewer antibiotic items were prescribed than if the intervention had not been made (1% of Northern Ireland's annual primary care antibiotic prescribing). A social norm feedback intervention reduced antibiotic prescribing in the intervention practices. The diminishing effect over time suggests the need for more frequent feedback. The RD method allowed measurement of the effectiveness of an intervention that was delivered as part of normal business, without a randomized trial.

Knowledge, attitude, perception and practice regarding antimicrobial use in upper respiratory tract infections in Qatar: a systematic review.

SummaryObjectiveTo explore the knowledge, attitude, perception and practice towards antimicrobial use in upper respiratory tract infections in patients visiting healthcare settings in Qatar.DesignSystematic review was performed using a predetermined protocol and in accordance with standardized reporting guidelines. MEDLINE, PubMed, EMBASE, Global Health and PsycINFO were searched for relevant published studies using relevant MESH terms and keywords.SettingAll healthcare settings in Qatar including both inpatient and ambulatory care.ParticipantsAll published articles exploring the antimicrobial use in upper respiratory tract infections at any health setting in Qatar were considered for inclusion in the study. No age, gender or population were excluded.Main Outcome Measure(s)The outcome of interest was antimicrobial use in upper respiratory tract infections in Qatar. We included all related studies to explore the knowledge, attitude, perception and practice for patients visiting all health care settings.ResultsThree articles were included, one in a primary care setting, one in a secondary care setting and one in the private sector. Overprescribing was noted in all settings. Our findings demonstrate low expectations to receive antibiotics, among the Qatari population, in primary care (28.1%). In fact, the majority of patients would be satisfied with reassurance rather than receiving antimicrobials. Many patients were satisfied with explanation from physicians and counselling. Private sector registered high prevalence of antimicrobial misuse for respiratory tract infections in which 85% deemed inappropriate. This finding was also noted at a medical intensive care unit which showed high antimicrobial use (76%) and respiratory tract infections accounted for 57% of prescriptions.ConclusionStudies are needed to determine factors and population-based rates of antimicrobial use in all healthcare settings. There is also a need for interventional programs for both physicians and public on appropriate use of antimicrobials to combat global antimicrobial resistance.

Antimicrobial use and drug-drug interactions among nursing home residents in Singapore: a multicentre prevalence study.

Background With the Ministry of Health's projected increase in nursing home beds and optimization of antimicrobial use in health care settings, it is therefore timely to consider baseline prevalence and patterns of antimicrobial use at nursing homes in Singapore as well as to evaluate the prevalence of potential clinically significant drug-drug interactions involving antimicrobials. Objective The primary objective was to determine the prevalence and patterns of antimicrobial use at nursing homes in Singapore. The secondary objective was to evaluate the prevalence of potential clinically significant drug-drug interactions involving antimicrobials. Setting Four nursing homes in Singapore. Method A retrospective cross-sectional study was conducted among nursing home residents. The antimicrobial prevalence, defined daily doses, days of therapy, and potential drug-drug interactions were determined using data from archived resident medication prescribing and administration records. Main outcome measure Prevalence and patterns of antimicrobial use, drug-drug interactions involving antimicrobials. Results Among 707 residents (mean age: 80.7 ± 8.8years, female: 57.1%), 10% used antimicrobials during the study month, with a 1-day point prevalence of 3%. The utilization rates of antimicrobials were 28.9 defined daily doses/1000 resident-days and 24.8days of therapy/1000 resident-days. Potential drug-drug interactions involving antimicrobials were identified among 32 of the 70 (46%) residents who were prescribed antimicrobials. Of these, 26 (81%) residents had 43 potential clinically significant drug-drug interactions. Conclusions The prevalence and utilization rates of antimicrobial use in Singapore nursing homes appear to be low. Yet, potential clinically significant drug-drug interactions are prevalent.

The impact of paediatric antimicrobial stewardship programmes on patient outcomes.

Although there has been an unprecedented global effort to reduce the spread of antimicrobial resistance, little emphasis has been placed on children. This review aims to evaluate the impact of paediatric antimicrobial stewardship programmes as well as providing a practical approach for effectively implementing them in community-based settings and in hospitals. Although rates of serious bacterial infection are low in children, the rates of antimicrobial use and resistance are comparable with adults. Different strategies are required to implement antimicrobial stewardship in community-based settings compared to in hospitals. Nationally coordinated, whole-system approaches have achieved long-term, sustainable reductions in antimicrobial prescribing, as well as reductions in resistance rates at population level, with no evidence of an increase in rate of serious infection or bacterial complications. Antimicrobial stewardship programmes in neonates and children have unique characteristics and issues. There is currently no consensus on how to measure consumption of antimicrobials in neonates and children. This is a research priority. Benchmarking and clinical networks in neonates and paediatrics are important to share practice and drive best use of antimicrobials.

Burden and Risk Factors of Antimicrobial Use in Children Less Than 5 Years of Age with Diarrheal Illness in Rural Bangladesh

Antimicrobial overuse contributes to antimicrobial resistance. Empiric use of antimicrobials for diarrheal illness is warranted only in a minority of cases, because of its self-limiting nature and multifactorial etiology. This study aims to describe the factors contributing to antimicrobial overuse for diarrheal disease among children less than 5 years of age in rural Bangladesh. A total of 3,570 children less than 5 years of age presenting with diarrhea in a tertiary level hospital were enrolled in the study. The rate of antimicrobial use at home was 1,395 (39%), compared with 2,084 (89%) during a hospital visit. In a multivariate analysis, factors associated with antimicrobial use at home included residence located more than 5 miles from a hospital; use of zinc and oral rehydration salts at home; vomiting; greater than 10 stools per 24 hours; diarrheal duration greater than 3 days; and rotavirus diarrhea (P < 0.05 for all). Characteristics of children more likely to be given antimicrobials in a health-care setting included greater than 10 stools per 24 hours; duration of diarrhea greater than 3 days; use of antimicrobials before hospital presentation; fever (≥ 37.8°C); rectal straining; and Shigella infection (P < 0.05 for all). The most commonly used drugs in rotavirus diarrhea were azithromycin and erythromycin, both before hospital presentation and during hospital admission. Our study underscores the importance of diligent vigilance on the rationale use of antimicrobials both at home and in health-care facilities with a special concern for children less than 5 years of age living in rural Bangladesh.

Multi-hospital point prevalence study of healthcare-associated infections in 28 adult intensive care units in Brazil

Healthcare-associated infection (HAI) represents a major problem for patient safety worldwide. To provide an up-to-date picture of the extent, aetiology, risk factors and patterns of infections in intensive care units (ICUs) in 28 Brazilian hospitals of different sizes. A one-day point prevalence survey in 2016 enrolled the ICUs of hospitals from the 12 meso-regions in Minas Gerais state, south-east Brazil. Hospitals were classified as university or non-university hospitals. All patients with >48 h of admission to the study ICUs at the time of the survey were included. In total, 303 patients were studied; of these, 155 (51.2%) were infected and 123 (79.4%) had at least one ICU-acquired infection. The most common ICU-acquired infections were pneumonia (53.0%) and bloodstream infection (27.6%). One hundred and nineteen bacterial isolates were cultured; the most common were Acinetobacter baumannii (27.1%), Pseudomonas aeruginosa (27.1%) and Staphylococcus aureus (39.0%). According to type of infection, the most common pathogens were P.aeruginosa (30.4%) in pneumonia, coagulase-negative staphylococci (23.4%) and Enterobacteriaceae (23.4%) in bloodstream infections, and Enterobacteriaceae (47.6%) in urinary tract infections. This study found that the overall prevalence of ICU-acquired infections in surveyed Brazilian hospitals was higher than that reported in most European countries and the USA. A greater proportion of infections were caused by non-fermenting Gram-negative bacteria. These observations, along with a high rate of antimicrobial use, illustrate the urgent need for HAIs to be a priority in the public health agenda of Brazil.

Burden of Hospital Acquired Infections and Antimicrobial Use in Vietnamese Adult Intensive Care Units.

BackgroundVietnam is a lower middle-income country with no national surveillance system for hospital-acquired infections (HAIs). We assessed the prevalence of hospital-acquired infections and antimicrobial use in adult intensive care units (ICUs) across Vietnam.MethodsMonthly repeated point prevalence surveys were systematically conducted to assess HAI prevalence and antimicrobial use in 15 adult ICUs across Vietnam. Adults admitted to participating ICUs before 08:00 a.m. on the survey day were included.ResultsAmong 3287 patients enrolled, the HAI prevalence was 29.5% (965/3266 patients, 21 missing). Pneumonia accounted for 79.4% (804/1012) of HAIs Most HAIs (84.5% [855/1012]) were acquired in the survey hospital with 42.5% (363/855) acquired prior to ICU admission and 57.5% (492/855) developed during ICU admission. In multivariate analysis, the strongest risk factors for HAI acquired in ICU were: intubation (OR 2.76), urinary catheter (OR 2.12), no involvement of a family member in patient care (OR 1.94), and surgery after admission (OR 1.66). 726 bacterial isolates were cultured from 622/1012 HAIs, most frequently Acinetobacter baumannii (177/726 [24.4%]), Pseudomonas aeruginosa (100/726 [13.8%]), and Klebsiella pneumoniae (84/726 [11.6%]), with carbapenem resistance rates of 89.2%, 55.7%, and 14.9% respectively. Antimicrobials were prescribed for 84.8% (2787/3287) patients, with 73.7% of patients receiving two or more. The most common antimicrobial groups were third generation cephalosporins, fluoroquinolones, and carbapenems (20.1%, 19.4%, and 14.1% of total antimicrobials, respectively).ConclusionA high prevalence of HAIs was observed, mainly caused by Gram-negative bacteria with high carbapenem resistance rates. This in combination with a high rate of antimicrobial use illustrates the urgent need to improve rational antimicrobial use and infection control efforts.

Surveillance of infection burden in residential aged care facilities

To explore the burden of illness associated with infectious syndromes and to measure the associated use of antimicrobials in residential aged care facilities (RACFs). Retrospective analysis of data for January 2006 to December 2010 from an infection surveillance system covering residents of four co-located RACFs, with a total of 150 residential care beds, in Melbourne, Victoria. Number of episodes and incidence of health care-associated infection (HCAI); rate of antimicrobial use; prescribing concordance with McGeer criteria for infection; frequency of clinical specimen collection. There were 1114 episodes of an infectious syndrome over 267, 684 occuppied bed-days (OBD), affording an average HCAI rate of 4.16 episodes/1000 OBD annually over 5 years (95% CI, 3.92-4.41). The mean rate of antimicrobial use was 7.07 courses/1000 OBD (range, 6.71-7.84). Around 40% of antimicrobial prescribing was for episodes that did not fulfil the McGeer criteria for clinical infection; this included about half of suspected urinary tract and upper respiratory tract infections (URTI), and about one-third of suspected lower respiratory tract and skin infections. Antimicrobials were routinely prescribed for URTI and bronchitis. Of all episodes treated with antimicrobials, 36% had documentation that a clinical specimen was obtained. The HCAI rate remained relatively stable over time. Routine surveillance and feedback of infection rates to the facilities did not result in a noticeable decrease of infection burden over time. It is of immediate concern that antimicrobials were being prescribed for a large proportion of suspected infections that did not meet criteria for clinical infection. Opportunities exist to further improve the use of antimicrobials in the RACF setting.

Antimicrobial Prescribing in Nursing Homes in Northern Ireland

In 2005, the European Commission recommended that all member states should establish or strengthen surveillance systems for monitoring the use of antimicrobial agents. There is no evidence in the literature of any surveillance studies having been specifically conducted in nursing homes (NHs) in Northern Ireland (NI). The aim of this study was to determine the prevalence of antimicrobial prescribing and its relationship with certain factors (e.g. indwelling urinary catheterization, urinary incontinence, disorientation, etc.) in NH residents in NI. This project was carried out in NI as part of a wider European study under the protocols of the European Surveillance of Antimicrobial Consumption group. Two point-prevalence surveys (PPSs) were conducted in 30 NHs in April and November 2009. Data were obtained from nursing notes, medication administration records and staff in relation to antimicrobial prescribing, facility and resident characteristics and were analysed descriptively. The point prevalence of antimicrobial prescribing was 13.2% in April 2009 and 10.7% in November 2009, with a 10-fold difference existing between the NHs with the highest and lowest antimicrobial prescribing prevalence during both PPSs. The same NH had the highest rate of antimicrobial prescribing during both April (30.6%) and November (26.0%). The group of antimicrobials most commonly prescribed was the penicillins (April 28.6%, November 27.5%) whilst the most prevalent individual antimicrobial prescribed was trimethoprim (April 21.3%, November 24.3%). The majority of antimicrobials were prescribed for the purpose of preventing urinary tract infections (UTIs) in both April (37.8%) and in November (46.7%), with 5% of all participating residents being prescribed an antimicrobial for this reason. Some (20%) antimicrobials were prescribed at inappropriate doses, particularly those which were used for the purpose of preventing UTIs. Indwelling urinary catheterization and wounds were significant risk factors for antimicrobial use in April [odds ratio {OR} (95% CI) 2.0 (1.1, 3.5) and 1.8 (1.1, 3.0), respectively] but not in November 2009 [OR (95% CI) 1.6 (0.8, 3.2) and 1.2 (0.7, 2.2), respectively]. Other resident factors, e.g. disorientation, immobility and incontinence, were not associated with antimicrobial use. Furthermore, none of the NH characteristics investigated (e.g. number of beds, hospitalization episodes, number of general practitioners, etc.) were found to be associated with antimicrobial use in either April or November 2009. This study has identified a high overall rate of antimicrobial use in NHs in NI, with variability evident both within and between homes. More research is needed to understand which factors influence antimicrobial use and to determine the appropriateness of antimicrobial prescribing in this population in general and more specifically in the management of recurrent UTIs.

Outpatient treatment of children with severe pneumonia with oral amoxicillin in four countries: the MASS study

A recent randomized clinical trial demonstrated home-based treatment of WHO-defined severe pneumonia with oral amoxicillin was equivalent to hospital-based therapy and parenteral antibiotics. We aimed to determine whether this finding is generalizable across four countries. Multicentre observational study in Bangladesh, Egypt, Ghana and Vietnam between November 2005 and May 2008. Children aged 3-59 months with WHO-defined severe pneumonia were enrolled at participating health centres and managed at home with oral amoxicillin (80-90 mg/kg per day) for 5 days. Children were followed up at home on days 1, 2, 3 and 6 and at a facility on day 14 to look for cumulative treatment failure through day 6 and relapse between days 6 and 14. Of 6582 children screened, 873 were included, of whom 823 had an outcome ascertained. There was substantial variation in presenting characteristics by site. Bangladesh and Ghana had fever (97%) as a more common symptom than Egypt (74%) and Vietnam (66%), while in Vietnam, audible wheeze was more common (49%) than at other sites (range 2-16%). Treatment failure by day 6 was 9.2% (95% CI: 7.3-11.2%) across all sites, varying from 6.4% (95% CI: 3.1-9.8%) in Ghana to 13.2% (95% CI: 8.4-18.0%) in Vietnam; 2.7% (95% CI: 1.5-3.9%) of the 733 children well on day 6 relapsed by day 14. The most common causes of treatment failure were persistence of lower chest wall indrawing (LCI) at day 6 (3.8%; 95% CI: 2.6-5.2%), abnormally sleepy or difficult to wake (1.3%; 95% CI: 0.7-2.3%) and central cyanosis (1.3%; 95% CI: 0.7-2.3%). All children survived and only one adverse drug reaction occurred. Treatment failure was more frequent in young infants and those presenting with rapid respiratory rates. Clinical treatment failure and adverse event rates among children with severe pneumonia treated at home with oral amoxicillin did not substantially differ across geographic areas. Thus, home-based therapy of severe pneumonia can be applied to a wide variety of settings.

Relationship Between Rates of Antimicrobial Consumption and the Incidence of Antimicrobial Resistance inStaphylococcus aureusandPseudomonas aeruginosaIsolates From 47 French Hospitals

To investigate relationships between rates of antimicrobial consumption and the incidence of antimicrobial resistance in Staphylococcus aureus and Pseudomonas aeruginosa isolates from hospitals. We conducted an observational study that used retrospective data from 2002 and linear regression to model relationships. Hospitals were asked to collect data on consecutive S. aureus and P. aeruginosa isolates, consumption rates for antibiotics (ie, anti-infectives for systemic use as defined by Anatomical Therapeutic Chemical class J01), and hospital characteristics, including infection control policies. Rates of methicillin resistance in S. aureus and rates of ceftazidime and ciprofloxacin resistance in P. aeruginosa were expressed as the percentage of isolates that were nonsusceptible (ie, either resistant or intermediately susceptible) and as the incidence of nonsuceptible isolates (ie, the number of nonsuceptible isolates recovered per 1,000 patient-days). The rate of antimicrobial consumption was expressed as the number of defined daily doses per 1,000 patient-days. Data were obtained from 47 French hospitals, and a total of 12,188 S. aureus isolates and 6,370 P. aeruginosa isolates were tested. In the multivariate analysis, fewer antimicrobials showed a significant association between the consumption rate and the percentage of isolates that were resistant than an association between the consumption rate and the incidence of resistance. The overall rate of antibiotic consumption, not including the antibiotics used to treat methicillin-resistant S. aureus infection, explained 13% of the variance between hospitals in the incidence of methicillin resistance among S. aureus isolates. The incidence of methicillin resistance in S. aureus isolates increased with the use of ciprofloxacin and levofloxacin and with the percentage of the hospital's beds located in intensive care units (adjusted multivariate coefficient of determination [aR(2)], 0.30). For P. aeruginosa, the incidence of ceftazidime resistance was greater in hospitals with higher consumption rates for ceftazidime, levofloxacin, and gentamicin (aR(2), 0.37). The incidence of ciprofloxacin resistance increased with the use of fluoroquinolones and with the percentage of a hospital's beds located in intensive care ( aR(2), 0.28). A statistically significant relationship existed between the rate of fluoroquinolone use and the rate of antimicrobial resistance among S. aureus and P. aeruginosa isolates. The incidence of resistant isolates showed a stronger association with the rate of antimicrobial use than did the percentage of isolates with resistance.

Clostridium difficile-Associated Disease in Patients in a Small Rural Hospital

To determine the risk factors for Clostridium difficile-associated disease (CDAD) in a 25-bed rural hospital and to compare antimicrobial use ratios at the study hospital with those at a large academic medical center. Case-control study. A 25-bed rural hospital in Iowa during the period from August 2002 through January 2005. A total of 17 case patients with CDAD and 34 control patients matched for age (ie, within 10 years of the case patient's age), sex, and admission date (ie, within 2 weeks of the case patient's admission date). Retrospective medical record review was performed to obtain data on antimicrobial exposures during the 6 weeks before hospital admission for both case and control patients. Exact conditional logistic regression was used for univariable and multivariable analyses. Antimicrobial use ratios were calculated to compare the rates of antimicrobial use for case and control patients at the study hospital with the rates for patients evaluated in a study of CDAD at a nearly 700-bed teaching hospital. Case patients had a larger cumulative number of days of antimicrobial use (P=.004), and they received a larger total number of antimicrobial agents during hospitalization (P=.001). Antimicrobial use ratios were higher for both case and control patients at the smaller hospital, compared with the larger hospital. CDAD at a small rural hospital was not associated with exposure to the antimicrobial classes that are typically associated with CDAD, but was instead related to the total number of antimicrobials used to treat patients. The rate of antimicrobial use for case and control patients was about 40% higher at the small rural hospital, compared with the corresponding rates at a large academic medical center.

Evaluation of the use of an on-farm system for bacteriologic culture of milk from cows with low-grade mastitis

To determine factors associated with implementation and use of an on-farm system for bacteriologic culture of milk from cows with lowgrade mastitis, including information on how producers used the on-farm bacteriologic culture system to guide antimicrobial selection practices and the resulting impact on patterns of antimicrobial use. Retrospective cohort study. Producers of 81 dairy farms. Farms that used an on-farm system for bacteriologic culture of milk from January 2001 to July 2003 were surveyed. Over half of those producers continuing to use the on-farm culture delayed antimicrobial treatment pending results of bacteriologic culture. Most other producers initiated empirical antimicrobial treatment while bacteriologic culture results were pending. Several barriers to the use of an on-farm system were identified. Significant reductions in rates of antimicrobial use were detected when comparing antimicrobial use rates before and during use of the on-farm system. Most producers chose to treat cows with mastitis caused by gram-positive pathogens with antimicrobials, whereas treatment choices for cows with mastitis caused by gram-negative bacteria and in cases in which no growth was detected varied. Readily available results permit antimicrobial selections to be made on the basis of the causative agent of mastitis. Adoption of an on-farm system for bacteriologic culture of milk may result in significant reductions in the percentage of cows treated with antimicrobials. Decreasing antimicrobial use may have several benefits including preventing unnecessary discarding of milk, decreasing the potential for drug residues in milk, and improving treatment outcomes as a result of targeted treatments.

Antimicrobial Use and Outcomes in Patients with Multidrug-Resistant and PansusceptibleSalmonellaNewport Infections, 2002–2003

Multidrug-resistant Salmonella Newport with decreased susceptibility to ceftriaxone (MDR-AmpC) is becoming increasingly common in its food animal reservoirs and in humans. Few data exist on rates of antimicrobial use or differences in clinical outcomes in persons infected with MDR-AmpC or other Salmonella strains. We conducted a case-comparison analysis of data from a multistate population-based case-control study to identify antimicrobial treatment choices and differences in clinical outcomes in those infected with MDRAmpC compared to pansusceptible S. Newport. Of isolates from 215 laboratory-confirmed S. Newport cases, 54 (25%) were MDR-AmpC, 146 (68%) were pansusceptible, and 15 (7%) had other resistance patterns; 146 (68%) patients with S. Newport were treated with antimicrobial agents and 66 (33%) were hospitalized. Over two-thirds of cases at low-risk for serious complications received antimicrobial therapy, most commonly with fluoroquinolones, to which this strain was susceptible. There were no significant differences in symptoms, hospitalization, duration of illness, or other outcomes between the persons infected with MDR-AmpC and pansusceptible S. Newport. Although currently prevalent MDR-AmpC S. Newport strains remains susceptible to the antimicrobial most commonly prescribed for it, continued efforts to reduce unnecessary use of antimicrobial agents in food animals and humans are critical to prevent further development of resistance to quinolones and cephalosporins, which is likely to lead to substantial adverse outcomes.

Impact of an electronic antibiotic advice and approval system on antibiotic prescribing in an Australian teaching hospital

The impact of a computer-based infectious diseases electronic antibiotic advice and approval system ("IDEA(3)S") was assessed as an alternative to a labour-intensive, phone-based approval system. IDEA(3)S-based approvals replaced 48% of all approvals for the most frequently requested antimicrobial agents (ceftriaxone/cefotaxime, vancomycin) and were associated with stable overall rates of antimicrobial use. Antibiotic prescribing for community-acquired pneumonia was 76% concordant with IDEA(3)S recommendations, and clinical acceptance of IDEA(3)S was excellent. Successful implementation required a coordinated, evidence-based approach between clinicians, pharmacists and hospital administration, together with ongoing staff education and feedback of results. IDEA(3)S is a useful new adjunct to routine clinician consultation to support appropriate antibiotic prescribing for a number of common indications in hospitals.

Current issues on resistance, treatment guidelines, and the appropriate use of fluoroquinolones for respiratory tract infections

Background: Community-acquired respiratory tract infections comprise a large percentage of diseases treated by primary care physicians, and rates of antimicrobial use for respiratory tract infections are increasing. The fluoroquinolones comprise a drug class with broad-spectrum activity against many of the key pathogens associated with community-acquired respiratory tract infections, including Streptococcus pneumoniae, and other significant pathogens, such as Staphylococcus aureus and Pseudomonas aeruginosa. While fluoroquinolones have gained popularity, the settings for their appropriate use in treating respiratory tract infections remain unclear.Objective: In this article, the mechanisms of fluoroquinolone resistance in S pneumoniae, treatment guidelines, and the mode of spread of resistance are reviewed.Methods: The authors conducted a MEDLINE search for articles published from 1990 to the present. Search terms included Streptococcus pneumoniae, fluoroquinolones, and resistance. Articles were selected for inclusion based on their relevance to the objective of this review.Results: Although 3 sets of treatment guidelines for community-acquired pneumonia (CAP) currently exist in the United States, a consensus for the role of fluoroquinolones in the outpatient management of CAP has not been achieved. Factors mitigating for restraint in the outpatient use of fluoroquinolones include concern for the spread of resistance to “innocent-bystander” organisms, such as S aureus and P aeruginosa, as well as possible inappropriate “trickle-down” use for other, less severe respiratory syndromes, such as bronchitis.Conclusion: Although the fluoroquinolones are potent agents against respiratory pathogens and have a clearly defined role in the treatment of hospitalized patients with CAP, their optimal role in the outpatient management of respiratory tract infections remains controversial.

The effect of vancomycin and third-generation cephalosporins on prevalence of vancomycin-resistant enterococci in 126 U.S. adult intensive care units.

Patient-specific risk factors for acquisition of vancomycin-resistant enterococci (VRE) among hospitalized patients are becoming well defined. However, few studies have reported data on the institutional risk factors, including rates of antimicrobial use, that predict rates of VRE. Identifying modifiable institutional factors can advance quality-improvement efforts to minimize hospital-acquired infections with VRE. To determine the independent importance of any association between antimicrobial use and risk factors for nosocomial infection on rates of VRE in intensive care units (ICUs). Prospective ecologic study. 126 adult ICUs from 60 U.S. hospitals from January 1996 through July 1999. All patients admitted to participating ICUs. Monthly use of antimicrobial agents (defined daily doses per 1000 patient-days), nosocomial infection rates, and susceptibilities of all tested enterococci isolated from clinical cultures. Prevalence of VRE (median, 10%; range, 0% to 59%) varied by type of ICU and by teaching status and size of the hospital. Prevalence of VRE was strongly associated with VRE prevalence among inpatient non-ICU areas and outpatient areas in the hospital, ventilator-days per 1000 patient-days, and rate of parenteral vancomycin use. In a weighted linear regression model controlling for type of ICU and rates of VRE among non-ICU inpatient areas, rates of vancomycin use (P < 0.001) and third-generation cephalosporin use (P = 0.02) were independently associated with VRE prevalence. Higher rates of vancomycin or third-generation cephalosporin use were associated with increased prevalence of VRE, independent of other ICU characteristics and the endemic VRE prevalence elsewhere in the hospital. Decreasing the use rates of these antimicrobial agents could reduce rates of VRE in ICUs.

Antimicrobial use in defined populations of infants and young children.

Antimicrobial overprescribing contributes to bacterial resistance, but data on use in infants and young children are limited. To assess antimicrobial use in a defined population of infants and young children and to determine diagnosis-specific prescribing rates for common infections. Retrospective cohort study of children served by 44 practices affiliated with 2 managed care organizations. Children aged 3 months to 72 months enrolled in either health plan between September 1, 1994, and August 31, 1996. Rates of antimicrobial use were calculated as the number of pharmacy dispensings divided by the number of person-years of observation contributed to the cohort in 2 age groups (3 to <36 months and 36 to <72 months). Other outcomes included the distribution of diagnoses associated with antimicrobial dispensing and population-based rates of diagnosis of common acute respiratory tract illnesses. A total of 46477 children contributed 59710 person-years of observation across the 2 health plans. Rates of antimicrobial dispensing for children aged 3 to 36 months were 3.2 and 2.1 dispensings per person-year in the 2 populations. A substantial fraction of younger children (35% in population A and 23% in population B) received 4 or more antimicrobial prescriptions in a single year. For children aged 36 to 72 months, the dispensing rates for the 2 populations were 2.0 and 1.5 antimicrobials per person-year. We found significant differences in rates between the populations studied and a decrease in use at all sites from 1995 to 1996. The diagnosis of otitis media accounted for 56% of antimicrobial drugs dispensed to children aged 3 to 36 months and 40% of those dispensed to children aged 36 to 72 months. Antimicrobial prescribing for colds and upper respiratory tract infections, bronchitis, and sinusitis was less frequent than previously reported but accounted for 10% to 14% of antimicrobial drugs dispensed. In these populations, otitis media accounted for the largest number of antimicrobial agents dispensed to children younger than 6 years. Clearly inappropriate indications such as cold, upper respiratory tract infection, and bronchitis accounted for smaller fractions of antimicrobial use but may be most amenable to change. However, interventions that encourage use of strict criteria for diagnosis and treatment of otitis media will likely have the greatest impact on overall antimicrobial exposure. Monitoring defined populations longitudinally will allow assessment of the effectiveness of such national and local initiatives.