Antimicrobial therapy of septicemic patients in intensive care units before and after blood culture reporting

Antibiotic Prescribing in Response to Bacterial Isolates in the Intensive Care Unit

This study aimed to identify potential knowledge-performance gaps in antibiotic prescribing for bacterial isolates in the Intensive Care Unit (ICU) in order to guide the development of interventions such as antibiotic policies, decision support, and improved systems for communication between the laboratory and the bedside. A prospective observational cohort study of all patients admitted to a mixed medical/surgical ICU was undertaken over a six-month period in an Australian adult tertiary hospital. From a cohort of 524 patients, 108 had 303 isolates that were eligible for inclusion. Overall, 14.3% and 30.8% of sterile and non-sterile isolates respectively were associated with inadequate initial antibiotic therapy after identification of the bacteria. After sensitivity results were available inadequate directed therapy was observed in 4.0% and 21.3% of sterile and non-sterile isolates respectively. Problems were most commonly associated with isolates of Pseudomonas spp., Stenotrophomonas spp., Acinetobacter spp., S. aureus, enterococci and group III Enterobacteriaceae. Inadequate antibiotic therapy was found to be independently associated with prolonged length of ICU stay. Narrower spectrum antibiotic therapy was potentially available for 30% of isolates after sensitivity results were known. We conclude that there is scope to improve antibiotic prescribing in the ICU by providing clinicians with access to information regarding local susceptibility patterns and intrinsic resistance of bacteria, and spectra of antibiotic cover. Timely notification of laboratory results at the point of care may also facilitate improved prescribing performance.

Impact of interventions by an antimicrobial stewardship program team on appropriate antimicrobial therapy in patients with bacteremic urinary tract infection

BACKGROUND

Inappropriate antimicrobial therapy often leads to poor outcomes. This study aimed to evaluate the impact of an antimicrobial stewardship program (ASP) team on appropriate therapy, in patients with bacteremic urinary tract infection (UTI).

PATIENTS AND METHODS

We retrospectively reviewed the interventions by the ASP team in 807 patients with bacteremic UTI. Interventions were divided into 3 groups: group A (conventional report), group B (conventional report and written alert on the chart), and group C (conventional report and oral recommendation with/without written alert). The appropriateness of antimicrobial therapy was assessed at 2 time points, based on blood culture results.

RESULTS

The ASP team estimated that 166 and 576 patients received inappropriate antimicrobial therapy based on the results of Gram staining, and final report, respectively. Appropriate therapy after intervention was administered to 53.2% of group A, 63.5% of group B, and 89.3% of group C patients, respectively. Mortality was significantly lower in patients of de-escalation than in those with no antimicrobial changes, without prolonged hospital stay.

CONCLUSION

This study provides one plausible benchmark for appropriate antimicrobial therapy by ASP, while observer bias and survivor treatment selection bias exist, and further studies including evaluation for severity are needed.

Electronic Alerts with Automated Consultations Promote Appropriate Antimicrobial Prescriptions

Background

To promote appropriate antimicrobial use in bloodstream infections (BSIs), we initiated an intervention program consisting of electronic alerts and automated infectious diseases consultations in which the identification and antimicrobial susceptibility test (ID/AST) results were reported.

Methods

We compared the appropriateness of antimicrobial prescriptions and clinical outcomes in BSIs before and after initiation of the program. Appropriateness was assessed in terms of effective therapy, optimal therapy, de-escalation therapy, and intravenous to oral switch therapy.

Results

There were 648 BSI episodes in the pre-program period and 678 in the program period. The proportion of effective, optimal, and de-escalation therapies assessed 24 hours after the reporting of the ID/AST results increased from 87.8% (95% confidence interval [CI] 85.5–90.5), 64.4% (95% CI 60.8–68.1), and 10.0% (95% CI 7.5–12.6) in the pre-program period, respectively, to 94.4% (95% CI 92.7–96.1), 81.4% (95% CI 78.4–84.3), and 18.6% (95% CI 15.3–21.9) in the program period, respectively. Kaplan-Meier analyses and log-rank tests revealed that the time to effective (p<0.001), optimal (p<0.001), and de-escalation (p = 0.017) therapies were significantly different in the two periods. Segmented linear regression analysis showed the increase in the proportion of effective (p = 0.015), optimal (p<0.001), and de-escalation (p = 0.010) therapies at 24 hours after reporting, immediately after program initiation. No significant baseline trends or changes in trends were identified. There were no significant differences in time to intravenous to oral switch therapy, length of stay, and 30-day mortality rate.

Conclusion

This novel form of stewardship program based on intervention by infectious disease specialists and information technology improved antimicrobial prescriptions in BSIs.

Lower antibiotic costs attributable to clinical microbiology rounds

OBJECTIVE

At our institution, our microbiologist, pharmacist, and infectious disease (ID) team meet to discuss ID patients, and this meeting is referred to as microbiology rounds. We hypothesized that our microbiology rounds reduce antibiotic costs. The study involved a review of 80 patients with an ID consultation order at each of the 3 hospitals: hospital A (HA) (only HA has microbiology rounds), hospital B (HB), and hospital C (HC). Of this population, we included patients with a positive blood culture. Thirty-six patients who met the above criteria were included in the study. The average antibiotic cost/patient/day at HA, HB, and HC were $66.0, $123, and $109, respectively. Also, we found that change in antibiotics was appropriate when compared to the final microbiology results in 90%, 44%, and 40% of the time at HA, HB, and HC, respectively. Herein, we found an association between conducting microbiology rounds and reduction of antibiotic cost.

Application of a 16S rRNA PCR-high-resolution melt analysis assay for rapid detection of Salmonella Bacteremia

Current culture and phenotypic protocols for diagnosing Salmonella infections can be time-consuming. Here, we describe the application of a 16S rRNA PCR coupled to high-resolution melt analysis (HRMA) for species and serotype identification within 6 h of blood sample collection from a patient with Salmonella enterica serotype Enteritidis bacteremia.

Improving antibiotic use in the hospital: Focusing on positive blood cultures is an effective option

OBJECTIVES

The unsolicited and systematic evaluation of positive blood cultures (pBC) after laboratory report by a single infectious disease specialist (IDS) was evaluated during one year, using a computer-generated alert by the laboratory. The main objectives of IDS counselling were to improve antibiotic use for bloodstream infection (i.e., initiating or modifying therapy) and to stop unjustified therapy for contaminated pBC.

METHODS

During the first part of the study (4 months), all pBC in patients from ICUs, medical and surgical wards were analyzed. After an interim analysis, only pBC from medical and surgical wards were evaluated during the second part (8 months).

RESULTS

Overall, 1090 episodes of pBC (representing 866 patients) were evaluated and classified as bloodstream infection (65.5%), contamination (29%) or undetermined (5.5%). Forty-three percent of episodes prompted IDS counselling, including initiation (5%), modification (27.5%), withdrawal (3.5%) and diagnosis workup (5%). Restricting the evaluation to medical and surgical wards increased the rate of counselling (61.2% vs. 27.7%, P<0.0001), notably for de-escalating (20% vs. 8%, P<0.0001), initiating (9% vs. 2%, P<0.0001), oral switch (6% vs. 2%, P<0.0001), withdrawing (5% vs. 2%, P=0.002) or reducing the duration of therapy (5% vs. 2%, P=0.002).

DISCUSSION AND CONCLUSIONS

In complement to the laboratory report, a computer-generated alert used by the IDS was useful for the management of pBC in hospital. The impact of IDS counselling was more effective when the evaluation was restricted to medical and surgical wards.

Current management of bloodstream infections

Bloodstream infection (BSI) is a frequent complication of invasive infections. The presence of bacteremia has therapeutic and prognostic implications. Here we review recent changes in the epidemiology, diagnosis and treatment of BSI (excluding candidemia). The evidence of the impact of healthcare-association in many community-onset episodes and the increase in drug-resistant pathogens causing BSI in the community and hospitals is reviewed. The emergence of molecular methods as an alternative tool for the diagnosis of BSI and novel aspects of clinical management, particularly of some multidrug-resistant organisms. Several quality indicators related to the diagnosis and management of bacteremia in hospitals are proposed.

Prescription of antibiotics in intensive care units in Latin America: an observational study

A one-day point prevalence study to investigate the patterns of antibiotic use was undertaken in 43 latin American (LA) intensive care units. Of 510 patients admitted, 231 received antibiotic treatment on the day of the study (45%); in 125 cases (54%) due to nosocomial-acquired infections. The most frequent infection reported was nosocomial pneumonia (43%). Only in 122 patients (53%) were cultures performed before starting antibiotic treatment. 33% of the isolated microorganisms were enterobacteriaceae (40% extended-spectrum beta-lactamase-producing), 23% methicillin-resistant Staphylococcus aureus and 17% carbapenems-resistant non-fermentative Gram-negatives. The antibiotics most frequently prescribed were carbapenems (99/231, 43%); alone (60/99, 60%) or in combination with vancomycin (39/99, 40%). "Restricted" antibiotics (carbapenems, vancomycin, piperacillin-tazobactam, broad-spectrum cephalosporins, tigecycline, polymixins and linezolid) were most frequently indicated in severely ill patients (APACHE II score at admission >15, p=0.0007 and, SOFA score at the beginning of the antibiotic treatment >3, p=0.0000). Only 36% of antibiotic treatments were cultured-directed.Our findings help explain the high rates of multidrug-resistant pathogens in LA settings (i.e. ESBL-producing Gram-negatives) and the severity of the registered patients illnesses.

Cost-effectiveness analysis of an antimicrobial stewardship team on bloodstream infections: a probabilistic analysis

OBJECTIVES

We sought to determine the cost-effectiveness of Antimicrobial Stewardship Teams (ASTs) on the reduction of morbidity and mortality associated with nosocomial bacteraemia.

METHODS

A decision analytic model compared costs and outcomes of bacteraemic patients receiving standard treatment with or without an AST consult. Patients with a bacteraemic event during their hospital admission were included in the model. Effectiveness was estimated as quality-adjusted life years (QALYs) over the lifetime of patients. Model variables and costs, along with their distributions, were obtained from the literature and expert opinion. Incremental cost-effectiveness ratios (ICERs) were calculated to estimate the cost per QALY gained from the hospital perspective. Uncertainty in ICERs was evaluated with probabilistic sensitivity analyses. The cost-effectiveness of clinical decision support systems was evaluated as a secondary analysis.

RESULTS

Implementing an AST for bacteraemia review cost $39,737 (95% CI $27,272-53, 017) and standard treatment cost $39,563 (95% CI $27,164-52,797). The difference in effectiveness between the two strategies was 0.08 QALYs, and the base case ICER from the probabilistic analysis was $2367 per QALY gained [95% CI dominant (less costly, more effective) to $24,379]. Results from the probabilistic sensitivity analysis demonstrated there was more than a 90% likelihood that an AST would be cost-effective at a level of $10,000 per QALY.

CONCLUSIONS

Maintaining an AST to improve care for bacteraemia is cost-effective from the hospital perspective. The estimate of $2367 per QALY gained for the AST intervention compares favourably with many currently funded healthcare interventions and services.

First notification of positive blood cultures and the high accuracy of the gram stain report

When blood cultures turn positive, the attending physicians are usually notified immediately about Gram stain findings. However, information on the accuracy of Gram staining is very limited. We examined the accuracy of preliminary blood culture reports provided by a regional laboratory in an observational study including the years 1996, 2000 to 2001, and 2003. We used data from computer files and technicians' laboratory notes. The study was restricted to cultures with one morphological type. Using cultural identification as a reference, we estimated the sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) for the following defined morphological groups: gram-positive cocci in clusters, gram-positive cocci in chains or diplococci, gram-positive rods, gram-negative cocci, gram-negative rods, and yeasts. We further evaluated the Gram stain and wet mount findings for the most frequent bacterial species/groups. We obtained 5,893 positive blood cultures and the following results for the defined groups: sensitivity, range of 91.3 to 99.7%; specificity, 98.9 to 100%; PPV, 94.6 to 100%; and NPV, 99.0 to 100%. The sensitivity for the most frequent species was in the range 91.3 to 100%, with nonhemolytic streptococci having the lowest value (sensitivity, 91.3%; 95% confidence interval, 86.2 to 94.9%). Wet mount reports were less accurate (sensitivity of 30 to 70% for species with peritrichous motility), and Enterobacteriaceae (notably Salmonella spp.) accounted for 25% of the reports stating polar motility. In conclusion, we demonstrated a high accuracy of Gram stain reports, whereas wet mount microscopy was generally less accurate.

Bloodstream infections: a trial of the impact of different methods of reporting positive blood culture results

BACKGROUND

The impact of how positive blood culture results are reported on the evolution bloodstream infections (BSIs) has not been assessed.

METHODS

We randomly assigned patients with BSIs into 3 groups: group A (for which physicians received a conventional report), group B (for which physicians received a conventional report and a written alert on the chart with clinical advice), and group C (for which physicians received the above plus oral clinical advice). The adequacy of therapy before and after receipt of the different types of information was assessed.

RESULTS

Overall, 297 episodes (109 in group A, 99 in group B, and 89 in group C) were studied. Patients who received inadequate treatment before receiving microbiological information had a longer mean (+/-SD) hospital stay (27.2+/-32.4 vs. 19.4+/-15.8 days; P=.017), a higher mean risk of Clostridium difficile-associated diarrhea (8.3% vs. 1.9%; P=.013), a higher mean overall mortality rate (30.8% vs. 19.4%; P=.025), and a higher mean risk of infection-related mortality (23.3% vs. 13.6%; P=.031). After receipt of microbiological reports, recommendations for changes in therapy were issued for patients in groups B (52.3%) and C (53.1%). For groups A, B, and C, the proportions of days on which adequate treatment was received were 66.3%, 92.1%, and 91.2% (P<.001); the mean numbers of defined daily doses of appropriate antibiotic therapy were 16.4, 22.2, and 20.7 (P=.003); the mean durations of hospital stay were 19.8, 23.6, and 24.1 days (P=.761); and the mortality rates during the late period were 12.9%, 15.6%, and 11% (P=.670), respectively. The mean costs of antimicrobials per episode in groups A, B, and C were 580.63, 537.98, and 434.53 (US707.85 dollars, US699.73 dollars, and US529.73 dollars, respectively).

CONCLUSIONS

Written- or oral-alert reports with clinical advice should complement traditional microbiological reports for patients with BSIs.

Use of indicators to evaluate the quality of community-acquired pneumonia management

Quality-assessment indicators for community-acquired pneumonia (CAP) founded on health care structure, process, and outcome have been recommended as a potential audit tool to evaluate the delivery of care. We prospectively audited the treatment of 205 patients admitted with CAP to 2 hospitals in Dundee against some of these key standards. Patients with severe CAP were more likely to die (mortality rate, 42% versus 7%) and to receive antibiotics by the intravenous route (relative risk [RR], 1.81; 95% confidence interval [CI], 1.38-2.37) and within 4 hours of admission to the hospital (RR, 1.22; 95% CI, 0.92-1.62). There was a lack of uniformity regarding the amount of oxygen prescribed, with evidence of poor case record and drug prescription chart documentation related to oxygen therapy. Adherence to the recommended antibiotic policy was associated with reduced risk of death or readmission to the hospital (RR, 0.58; 95% CI, 0.34-1.00). However, in a multivariate analysis, severity of pneumonia was the strongest predictor of death or readmission (P=.004), and adherence to the antibiotic policy was not statistically significant (P=.154). Our study has confirmed the value of quality indicators in evaluating our CAP management and has stimulated the development and implementation of a local hospital-based integrated care pathway.

Do guidelines for community-acquired pneumonia improve the cost-effectiveness of hospital care?

There is growing pressure to demonstrate the value of practice guidelines. We have reviewed the evidence that guidelines for the treatment of community-acquired pneumonia (CAP) change current practices and that the standardization of practices reduces costs and/or improves outcome. The most obvious barrier to implementation of the guidelines is lack of knowledge about their content; equally important are the attitudes and behavior of professionals, patients, and their caregivers. Guidelines may improve the outcome of CAP, provided that there is an association between variations in outcome and some specific processes of care. Conversely, when there is no such relationship, guidelines may reduce the cost of care without having an adverse effect on outcome. The cost-effectiveness of CAP guidelines in an individual hospital depends on the systems that are available to identify patients with CAP and to measure the processes of care. There is good evidence that following the recommendations of the CAP guidelines does improve the cost-effectiveness of care and, therefore, that an audit of CAP may be worth the effort.

The impact of the first notification of positive blood cultures on antibiotic therapy. A one-year survey

The impact on antibiotic therapy of the first notification of positive blood cultures was assessed for 735 episodes of bacteraemia detected during 1992 in the County of Northern Jutland, Denmark. A primary focus of infection was defined in 498 episodes, the urinary tract being the most frequent (n = 182, 25%). Twenty-nine patients (3.5%) had died prior to the initial contact. In 12 episodes antibiotic therapy had either been stopped or data were not available, leaving 694 episodes for further assessment. In 567 episodes antibiotic therapy had been started prior to the initial contact, the most frequent regimen being ampicillin or an ampicillin-aminoglycoside combination (295 episodes), whereas cephalosporins, thienamycin, and fluoroquinolones were seldom used (41 episodes). The ongoing antibiotic coverage was deemed appropriate in 418 episodes (60%), non-optimal in 90 (13%), and lacking in 186 (27%). The notification of positive blood cultures elicited changes in antibiotic therapy in 315 episodes (45%), including commencement of antibiotic therapy in 127 (18%). Thus, blood culture results have a measurable impact on antibiotic therapy.

Incidence and clinical significance of positive blood cultures in febrile episodes of patients with hematological malignancies

The characteristics of 554 febrile episodes in 126 patients with a hematological malignancy over a 6-year period (1985-90) were reviewed in order to study the current incidence and clinical significance of blood culture positivity. An infection was documented microbiologically in 28% and clinically in 30% of the episodes. Blood cultures were positive in 19% of the febrile episodes. The rate of blood culture positivity was unrelated to the type of hematological malignancy, to neutropenia and to the presence of infection foci. 21% (26/126) of the patients died of sepsis-related causes. Sepsis-related death occurred in 23% of the blood culture positive febrile episodes, with a median survival time of 2 days. Infection prophylaxis did not reduce either the rate of blood culture positivity or the rate of sepsis-related deaths. Thus, the small proportion of febrile episodes whose fever etiology could be established by blood culture represented 'the tip of the iceberg', i.e. rapidly lethal septic infections with a high mortality rate. This fatality could neither be predicted by a search for infection foci nor prevented by infection prophylaxis.