Impact of antibiotic changes in empirical therapy on antimicrobial resistance in intensive care unit-acquired infections

Hospital-wide surveillance-based antimicrobial treatments: A Monte-Carlo look-ahead method

BACKGROUND AND OBJECTIVES

We present a heuristic solution method to the problem of choosing hospital-wide antimicrobial treatments that minimize the cumulative infected patient-days in the long run in a health care facility.

METHODS

Our solution method is a rollout algorithm. We rely on the stochastic version of a compartmental model to describe the spread of an infecting organism in the health care facility and the emergence and spread of resistance to two drugs. We assume that the parameters of the model are known. Treatments are chosen at the beginning of each period based on the count of patients with each health status, and on stochastic simulations of the future emergence and spread of antimicrobial resistance. The same treatment is then administered to all patients, including uninfected patients, during the period and cannot be adjusted until the next period.

RESULTS

In our simulations, our algorithm allows to reduce the average cumulative infected patient-days over two years by 47.0% compared to the best standard therapy, and by 32.2% compared to a similar heuristic algorithm not using surveillance data (significantly at the 95% threshold).

CONCLUSION

Our heuristic solution method is simple yet flexible. We explain how it can be used either to perform online optimization, or to produce data for quantitative analysis. Its performance is illustrated using a relatively simple infectious disease transmission model, but it is compatible with more advanced epidemiological models.

Antimicrobial resistance trends in methicillin-resistant and methicillin-susceptible Staphylococcus aureus and Staphylococcus epidermidisisolates obtained from patients admitted to intensive care units. 2010-2015

Introducción. La aparición y la diseminación de cepas resistentes en hospitales, principalmente en unidades de cuidado intensivo (UCI), se han convertido en un serio problema de salud pública.Objetivo. Analizar la tendencia de los fenotipos de resistencia de Staphylococcus aureus y Staphylococcus epidermidis resistentes y susceptibles a meticilina aislados en pacientes atendidos en UCI de un hospital de alta complejidad de Cartagena, Colombia, del 2010 al 2015.Materiales y métodos. Estudio analítico transversal realizado entre enero de 2010 y diciembre de 2015. Se utilizaron aislamientos de S. aureus y S. epidermidis meticilino-susceptibles y meticilino-resistentes (SARM, SASR, SERM y SESM). La técnica de susceptibilidad empleada fue el método microdilución en caldo para la detección de la concentración mínima inhibitoria.Resultados. Se identificaron 313 aislamientos de Staphylococcus spp., la mayoría resistentes a meticilina (63.6%). Las cepas SARM y SERM correspondieron al 13.7% y al 27.8% del total de aislamientos, respectivamente. Los mayores porcentajes de resistencia en SARM y SERM correspondieron a eritromicina (57.6% y 81.2%, respectivamente), clindamicina (54.6% y 71.0%), ciprofloxacina (48.4% y 36.4%) y trimetoprima-sulfametoxazol (36.4% y 51.4%).Conclusión. Los resultados encontrados sugieren el replanteamiento de las estrategias de control de la resistencia antimicrobiana en el hospital objeto de estudio.

Emergence of antibiotic resistance Pseudomonas aeruginosa in intensive care unit; a critical review

The emergence of antibiotic resistant bacteria in the healthcare is a serious concern. In the Healthcare premises precisely intensive care unit are major sources of microbial diversity. Recent findings have demonstrated not only microbial diversity but also drug resistant microbes largely habitat in ICU. Pseudomonas aeruginosa found as a part of normal intestinal flora and a significant pathogen responsible for wide range of ICU acquired infection in critically ill patients. Nosocomial infection associated with this organism including gastrointestinal infection, urinary tract infections and blood stream infection. Infection caused by this organism are difficult to treat because of the presence of its innate resistance to many antibiotics (β-lactam and penem group of antibiotics), and its ability to acquire further resistance mechanism to multiple class of antibiotics, including Beta-lactams, aminoglycosides and fluoroquinolones. In the molecular evolution microbes adopted several mechanism to maintain genomic plasticity. The tool microbe use for its survival is mainly biofilm formation, quorum sensing, and horizontal gene transfer and enzyme promiscuity. Such genomic plasticity provide an ideal habitat to grow and survive in hearse environment mainly antibiotics pressure. This review focus on infection caused by Pseudomonas aeruginosa, its mechanisms of resistance and available treatment options. The present study provides a systemic review on major source of Pseudomonas aeruginosa in ICU. Further, study also emphasizes virulence gene/s associated with Pseudomonas aeruginosa genome for extended drug resistance. Study gives detailed overview of antibiotic drug resistance mechanism.

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.

Trend and seasonality of community-acquired Escherichia coli antimicrobial resistance and its dynamic relationship with antimicrobial use assessed by ARIMA models

INTRODUCTION

We studied the trend and seasonality of community-acquired Escherichia coli resistance and quantified its correlation with the previous use of certain antibiotics.

METHODS

A time series study of resistant community-acquired E. coli isolates and their association with antibiotic use was conducted in a Primary Health Care Area from 2008 to 2012. A Poisson regression model was constructed to estimate the trend and seasonality of E. coli resistance.

RESULTS

A significant increasing trend in mean E. coli resistance to cephalosporins, aminoglycosides and nitrofurantoin was observed. Seasonal resistance to ciprofloxacin and amoxicillin-clavulanic acid was significantly higher in autumn-winter. There was a delay of 7, 10 and 12 months between the use of cotrimoxazole (P<0.038), fosfomycin (P<0.024) and amoxicillin-clavulanic acid (P<0.015), respectively, and the occurrence of E. coli resistance.

CONCLUSIONS

An average delay of 10 months between the previous use of amoxicillin-clavulanic acid, cotrimoxazole and fosfomycin and the appearance of resistant community-acquired E. coli strains was detected.

Antibiotic Cycling and Antibiotic Mixing: Which One Best Mitigates Antibiotic Resistance?

Can we exploit our burgeoning understanding of molecular evolution to slow the progress of drug resistance? One role of an infection clinician is exactly that: to foresee trajectories to resistance during antibiotic treatment and to hinder that evolutionary course. But can this be done at a hospital-wide scale? Clinicians and theoreticians tried to when they proposed two conflicting behavioral strategies that are expected to curb resistance evolution in the clinic, these are known as “antibiotic cycling” and “antibiotic mixing.” However, the accumulated data from clinical trials, now approaching 4 million patient days of treatment, is too variable for cycling or mixing to be deemed successful. The former implements the restriction and prioritization of different antibiotics at different times in hospitals in a manner said to “cycle” between them. In antibiotic mixing, appropriate antibiotics are allocated to patients but randomly. Mixing results in no correlation, in time or across patients, in the drugs used for treatment which is why theorists saw this as an optimal behavioral strategy. So while cycling and mixing were proposed as ways of controlling evolution, we show there is good reason why clinical datasets cannot choose between them: by re-examining the theoretical literature we show prior support for the theoretical optimality of mixing was misplaced. Our analysis is consistent with a pattern emerging in data: neither cycling or mixing is a priori better than the other at mitigating selection for antibiotic resistance in the clinic.

Key words: antibiotic cycling, antibiotic mixing, optimal control, stochastic models.

A Survey of Antimicrobial Stewardship Programs in Korea, 2015

The study was conducted to evaluate the Antibiotic Stewardship Program (ASP) in Korean hospitals compared with the previous two surveys in 2006 and 2012. The information on ASPs was collected through an online-based survey sent by e-mail to 192 infectious diseases specialists in 101 Korean hospitals in September 2015. Fifty-four hospitals (53.5%, 54/101) responded to the online survey. One infectious diseases specialist was employed in 30 (55.6%) of the 54 hospitals, and they were in charge of ASPs in hospitals with the program. Fifty of the 54 hospitals (92.6%) had ASPs and the same number of hospitals was conducting a preauthorization-of-antibiotics-use program. Although most hospitals adopted preauthorization strategies for more antibiotics in 2015 than in 2012 (median 14 in 2015; 13 in 2012), a limited number of antibiotics were under control. The number of per oral and parenteral antibiotics available in hospitals in 2015 decreased compared to 2006 and 2012. The number of hospitals performing a retrospective or prospective qualitative drug use evaluation of antibiotic use increased from 2006 to 2015. Manpower in charge of antibiotic stewardship in most hospitals was still very limited and ASPs heavily depended on preauthorization-of-antibiotics-use programs in this survey. In conclusion, there leaves much to be desired in ASPs in Korea in 2015.

Evaluation of a Mixing versus a Cycling Strategy of Antibiotic Use in Critically-Ill Medical Patients: Impact on Acquisition of Resistant Microorganisms and Clinical Outcomes

Objective

To compare the effect of two strategies of antibiotic use (mixing vs. cycling) on the acquisition of resistant microorganisms, infections and other clinical outcomes.

Methods

Prospective cohort study in an 8-bed intensive care unit during 35- months in which a mixing-cycling policy of antipseudomonal beta-lactams (meropenem, ceftazidime/piperacillin-tazobactam) and fluoroquinolones was operative. Nasopharyngeal and rectal swabs and respiratory secretions were obtained within 48h of admission and thrice weekly thereafter. Target microorganisms included methicillin-resistant S. aureus, vancomycin-resistant enterococci, third-generation cephalosporin-resistant Enterobacteriaceae and non-fermenters.

Results

A total of 409 (42%) patients were included in mixing and 560 (58%) in cycling. Exposure to ceftazidime/piperacillin-tazobactam and fluoroquinolones was significantly higher in mixing while exposure to meropenem was higher in cycling, although overall use of antipseudomonals was not significantly different (37.5/100 patient-days vs. 38.1/100 patient-days). There was a barely higher acquisition rate of microorganisms during mixing, but this difference lost its significance when the cases due to an exogenous Burkholderia cepacia outbreak were excluded (19.3% vs. 15.4%, OR 0.8, CI 0.5–1.1). Acquisition of Pseudomonas aeruginosa resistant to the intervention antibiotics or with multiple-drug resistance was similar. There were no significant differences between mixing and cycling in the proportion of patients acquiring any infection (16.6% vs. 14.5%, OR 0.9, CI 0.6–1.2), any infection due to target microorganisms (5.9% vs. 5.2%, OR 0.9, CI 0.5–1.5), length of stay (median 5 d for both groups) or mortality (13.9 vs. 14.3%, OR 1.03, CI 0.7–1.3).

Conclusions

A cycling strategy of antibiotic use with a 6-week cycle duration is similar to mixing in terms of acquisition of resistant microorganisms, infections, length of stay and mortality.

Agreement on the prescription of antimicrobial drugs

BACKGROUND

There is universal awareness of the difficulties faced by doctors when prescribing antimicrobials.

METHODS

Over a six-month period patients hospitalized in the ICU and under treatment with antibiotics and/or antifungals were eligible to participate in the study. The data were assessed by two infectious diseases specialists. Once completed, all case forms were sent independently to both evaluators (TZSC and ARM) by e-mail. Based on the data received, the evaluator completed a form automatically generated on the e-mail and returned it to the original mailbox for further analysis. We assessed the level of agreement between infectious disease specialists and the physicians directly responsible for the decision to begin antimicrobial therapy, as well as to assess the appropriateness of the regimen prescribed.

RESULTS

Among the antimicrobial regimens prescribed to the 177 patients, 36% were considered inappropriate by specialist #1 and 38% were considered inappropriate by specialist #2. We found 78% agreement by at least one of the infectious disease specialists with the prescribed antimicrobial regimen, and in 49% of cases both specialists agreed with the prescribed regimen. Both disagreed with the prescribed regimen in 22% of the cases and they disagreed between themselves in 29% of the cases.

CONCLUSION

This study highlights the difficulties in prescribing effective empirical antimicrobial therapy--they are of such magnitude that even two specialists in infectious diseases, well acquainted with our hospital's resistance patterns and our patients' profiles have considerable disagreement.

Antibiotic resistance in the intensive care unit setting

Antibiotic resistance is an important factor influencing clinical outcome for patients in intensive care units. It is also associated with increased healthcare costs resulting from prolonged patient stays. The problem of antibiotic resistance is particularly acute in intensive care units because they house seriously ill patients who are predisposed to infection, as a result of which, antibiotic use is extremely common. Strategies for controlling resistance in intensive care units have focused on attempting to reduce unnecessary antibiotic use, while at the same time ensuring adequate antibiotic cover is provided. The formulation of policies for the effective use of antibiotics in individual intensive care units requires a multidisciplinary approach, entailing regular epidemiological surveillance, together with input from critical care specialists, infectious disease specialists and pharmacists.

Antimicrobial stewardship in hospitals: Does it work and can we do it?

Selection of resistant pathogens by antimicrobial use is probably the most important cause of antimicrobial resistance. Antimicrobial stewardship (AMS) refers to a multifaceted approach to optimise prescribing. The benefits of AMS programmes have been widely demonstrated in terms of reductions in antimicrobial use, mortality, Clostridium difficile and other healthcare-associated infections, hospital length of stay and bacterial resistance. Several kinds of interventions (i.e. restriction of drugs, pre-authorisation of certain antimicrobials, joint clinical rounds with prescribers, implementation of guidelines and education) have shown positive results. Regrettably, in most hospitals in Latin America, Asia and Africa as well as in a significant proportion of institutions in Europe and North America, essential human and material resources are scarce or absent, and teams are neither developed nor well functioning. Despite current or potential barriers, we should start or improve our already ongoing initiatives on AMS by considering the main specific problems and act accordingly with the available human and material resources. From supervising the use of specific classes of drugs to implementing more sophisticated decision support programmes, there is a wide range of possible useful interventions.

Antimicrobial stewardship: bridging the gap between quality care and cost

PURPOSE OF REVIEW

Antibiotic resistance continues to rise, whereas development of new agents to counter it has slowed. A heightened need exists to maintain the effectiveness of currently available agents. This review focuses on the need for better antimicrobial stewardship, expected benefits of well designed antimicrobial stewardship programs (ASPs), and provides suggestions for development of an effective ASP.

RECENT FINDINGS

Healthcare-associated infections (HAIs) are a significant cause of poor treatment outcomes and elevated healthcare and societal costs worldwide. HAIs are often caused by antibiotic-resistant pathogens; overuse of antibiotics has been linked with antibiotic resistance. Benefits of improved antimicrobial stewardship include reduced emergence of antibiotic resistance, limitation of drug-related adverse events, minimization of other consequences of antibiotic use (e.g., superinfection), and reduction of societal and healthcare-related costs. In 2007, the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA) provided guidelines for the development of institutional programs to enhance antimicrobial stewardship. Experiences at The Ohio State University Medical Center (OSUMC) reinforce this message, while providing specific examples of ways to optimize ASP development and implementation. The focus of an ASP should be on improving quality of care, reducing drug resistance, and cost savings. When implementing an ASP, it is important to identify those most likely to resist the ASP, understand their concerns, and develop easy-to-understand messages that address these concerns and highlight the benefits of the proposed changes. Antibiograms play a key role in identifying local and interdepartmental trends in antibiotic susceptibility or resistance. These data are important not only in devising best-treatment practices for the institution, but also in evaluating the impact of a recently implemented ASP. Other measures of the impact of an ASP should include patient outcomes and overall costs or savings.

SUMMARY

Better antimicrobial stewardship is needed to limit the emergence of antibiotic resistance, prolong the effectiveness of currently available agents, improve patient outcomes, and reduce healthcare and societal costs associated with HAIs. Guidelines from the IDSA/SHEA and experiences at OSUMC provide examples of how best to develop an institutional ASP to accomplish these goals.

Infection reduction strategies including antibiotic stewardship protocols in surgical and trauma intensive care units are associated with reduced resistant gram-negative healthcare-associated infections

BACKGROUND

Resistance to broad-spectrum antibiotics by gram-negative organisms is increasing. Resistance demands more resource utilization and is associated with patient morbidity and death. We describe the implementation of infection reduction protocols, including antibiotic stewardship, and assess their impact on multi-drug-resistant (MDR) healthcare-acquired gram-negative infections.

METHODS

Combined infection reduction and antibiotic stewardship protocols were implemented in the surgical and trauma intensive care units at Vanderbilt University Hospital beginning in 2002. The components of the program were: (1) Protocol-specific empiric and therapeutic antibiotics for healthcare-acquired infections; (2) surgical antibiotic prophylaxis protocols; and (3) quarterly rotation/limitation of dual antibiotic classes. Continuous healthcare-acquired infection surveillance was conducted by independent practitioners using National Heath Safety Network criteria. Linear regression analysis was used to estimate trends in MDR gram-negative healthcare-acquired infections.

RESULTS

A total of 1,794 gram-negative pathogens were isolated from healthcare-acquired infections during the eight-year observation period. The proportion of healthcare-acquired infections caused by MDR gram-negative pathogens decreased from 37.4% (2001) to 8.5% (2008), whereas the proportion of healthcare-acquired infections caused by pan-sensitive pathogens increased from 34.1% to 53.2%. The rate of total healthcare-associated infections per 1,000 patient-days that were caused by MDR gram-negative pathogens declined by -0.78 per year (95% confidence interval [CI] -1.28, -0.27). The observed rate of healthcare-acquired infections per 1,000 patient days attributable to specific MDR gram-negative pathogens decreased over time: Pseudomonas -0.14 per year (95% CI -0.20, -0.08), Acinetobacter-0.49 per year (95% CI -0.77, -0.22), and Enterobacteriaceae -0.14 per year (95% CI -0.26, -0.03).

CONCLUSION

Implementation of an antibiotic stewardship protocol as a component of an infection reduction campaign was associated with a decrease in resistant gram-negative healthcare-acquired infections in intensive care units. These results further support widespread implementation of such initiatives.

Critical analysis of empiric antibiotic utilization: establishing benchmarks

AIM

We critically evaluated empiric antibiotic practice in the surgical and trauma intensive care unit (STICU) with three specific objectives: (1) To characterize empiric antibiotics practice prospectively; (2) to determine how frequently STICU patients started on empiric antibiotics subsequently have a confirmed infection; and (3) to elucidate the complications associated with unnecessary empiric antibiotic therapy.

METHODS

We collected data prospectively using the Surgical Intensive Care-Infection Registry (SIC-IR) including all 1,185 patients admitted to the STICU for >2 days from March 2007 through May 2008. Empiric antibiotics were defined as those initiated because of suspected infections.

RESULTS

The mean patient age was 56 years and 62% were male. The mean STICU length of stay was eight days, and the mortality rate was 4.6%. Empiric antibiotics were started for 26.3% of the patients. The average length of antibiotic use was three days. Of the 312 patients started on empiric antibiotics, only 25.6% were found to have an infection. Factors associated with correctly starting empiric antibiotics were a longer STICU stay (5 vs. 3 days), prior antibiotics (29% vs. 17%), and mechanical ventilation (93% vs. 79%). Patients who were started on antibiotics without a subsequent confirmed infection were compared with patients not given empiric antibiotics. Incorrect use of empiric antibiotics was associated with younger age (p < 0.001), more STICU days (10.6 vs. 5.9 days; p < 0.001), more ventilator days (p < 0.001), more development of acute renal failure (24.1% vs. 12.1%; p < 0.001), and a significant difference in mortality rate (8.6% vs. 3.2%; p < 0.001).

CONCLUSIONS

After admission to the STICU, 26% of patients received at least one course of empiric antibiotics. Only 25.6% of these patients were confirmed to have an infection. These results provide key benchmark data for the critical care community to improve antibiotic stewardship.

Antimicrobial stewardship program directed at broad-spectrum intravenous antibiotics prescription in a tertiary hospital

The antimicrobial stewardship program (ASP) is a major strategy to combat antimicrobial resistance and to limit its expenditure. We have improved on our existing ASP to implement a sustainable and cost-effective two-stage immediate concurrent feedback (ICF) model, in which the antimicrobial prescription is audited by two part-time infection control nurses at the first stage, followed by "physician ICF" at the second stage. In January 2005, an ASP focused on broad-spectrum intravenous antibiotics was implemented. All in-patients, except from the intensive care, bone marrow transplantation, liver transplantation, pediatric, and private units, being treated with broad-spectrum intravenous antibiotics were included. The compliance to ICF and "physician ICF", antibiotics usage density measured by expenditure and defined daily doses (DDD) were recorded and analyzed before and after the ASP. The overall conformance rate to antibiotic prescription guidelines was 79.4%, while the conformance to ICF was 83.8%. Antibiotics consumption reduced from 73.06 (baseline, year 2004) to 64.01 (year 2007) per 1,000 patient bed-day-occupancy. Our model can be easily applied even in the clinical setting of limited resources.

The evolution of drug-resistant microorganisms in patients with prolonged mechanical ventilation

BACKGROUND

Patients requiring prolonged mechanical ventilation (PMV) tend to become reservoirs of antimicrobial resistance. We assessed antimicrobial-resistant microorganisms in the respiratory tracts of patients receiving PMV.

METHODS

Over a 6-month period, the microorganisms from tracheal aspirates of PMV patients with lower airway infection were analyzed.

RESULTS

Antimicrobial use was greatest during the acute critical stage of respiratory failure. Antimicrobial resistance in Pseudomonas aeruginosa and Klebsiella pneumoniae peaked during the fourth to 15th weeks of PMV. Methicillin-resistant Staphylococcus aureus (MRSA) developed rapidly during the first 3 weeks of PMV. The acquisition of multidrug-resistant P aeruginosa and MRSA were significantly correlated with previous exposure to ceftazidime (odds ratio [OR] = 121.3 and 72.5; P = .01 and .01, respectively). The rise of multidrug-resistant Acinetobacter baumannii was significantly correlated with previous exposure to piperacillin/tazobactam (OR = 26.81; P = .02) and imipenem (OR = 16.91; P = .03). Using univariate and multivariate logistic regression models, the lower respiratory tract infections with multidrug-resistant microorganisms were independently associated with increased 6-month mortality (OR = 3.41; P < .01).

CONCLUSION

In patients receiving PMV, lower respiratory tract infection with multidrug-resistant microorganisms is common and is associated with higher mortality.

Five-year surveillance of antimicrobial use in Chinese Pediatric Intensive Care Units

In order to demonstrate antibiotic usage in Chinese Pediatric Intensive Care Units (PICUs), and provide some data to further study on relation of antimicrobial use and resistance. We reviewed the use of antibiotics in Chinese PICUs from 2002 to 2006. All data, including general data and antibiotic use data, were obtained from five PICUs of pediatric teaching hospitals in China. The results of antibiotic use were expressed as defined daily doses (DDDs) per 100 patient-days by WHO in this study. All 12 743 patients were included from the five PICUs in this study. Length of stay in PICUs was essentially unchanged, but the percentage of antimicrobial costs vs. drug costs dramatically decreased in this study period (p < 0.01). The percentage of empiric treatment decreased by year (from 82.2% to 70.2%). while the percentage of therapeutic treatment increased by year (from 11.2% to 24.2%) from 2002 to 2006. Total antibiotic usage decreased from 72.1 DDDs per 100 patient-days to 35.5 DDDs per 100 patient-days from 2002 to 2006 (p < 0.05). The significant increase was found in the DDDs per 100 patient-days of second generation cephalosporins in this study (p < 0.05). While usages of the some antibiotics decreased, for example penicillins, third-generation cephalosporins, and macrolides in this study period. The data of antimicrobial use were obtained from five PICUs of biggest pediatric teaching hospital in this 5-year period, which could serve as a basis of antibiotic treatment and a benchmark in future study of antibiotic use.

Antimicrobial usage in paediatric intensive care units in China

AIM

The aim of the study was to determine antimicrobial usage in paediatric intensive care units (PICUs) in China.

METHODS

Data were equally collected from 540 charts of PICUs in the three Chinese tertiary teaching children hospitals in 2006. The data included demographic, clinical data and those on antimicrobial usage and results of microbiological examinations.

RESULTS

Of the 540 cases, 524 (94.7%) patients received at least one antimicrobial agent. The main treatment started empirically in 387 (71.6%). The third-generation cephalosporins were the major antimicrobials used in all participating hospitals, accounting for 227 (31%). Bacteria were isolated from 48%, 68% and 59% of the three PICUs. Six common pathogens accounted for more than 75% of the isolated bacteria. The rates of Escherichia coli isolates resistant to cefotaxime were 73.8%, 58.3% and 49.2%, respectively, with the rate being higher in H1 than in H2 and H3 (both p<0.01).

CONCLUSIONS

Irrational use of antimicrobials exists in clinical practice of PICUs in China. It is recommended that antimicrobial usage should be guided by bacterial isolation and antimicrobial susceptibility tests in order to select correct antimicrobials and to prevent emergency of drug-resistant strains in PICUs.

Implementation of antibiotic rotation protocol improves antibiotic susceptibility profile in a surgical intensive care unit

BACKGROUND

Antibiotic rotation has been proposed as a way to potentially reduce the development of antimicrobial resistant bacteria in intensive care units. We assessed the effect of an antibiotic rotation protocol on the antibiotic susceptibility profiles of three clinically relevant gram-negative microorganisms within our surgical intensive care unit (SICU).

METHODS

Our SICU implemented an antibiotic rotation protocol in 2003. Four antibiotics (piperacillin/tazobactam, imipenem/cilastin, ceftazidime, and ciprofloxacin) were rotated as the primary antibiotic used to treat suspected gram-negative infections every month, with the four-drug cycle being repeated every 4 months. Antibiotic susceptibility data for three microorganisms (Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae) were collected for the year before (2002) and the year after (2004) the implementation of the rotation protocol. Changes in antimicrobial susceptibility rates were analyzed for the three microorganisms. As a comparison, a similar analysis was conducted for microorganisms isolated from our medical intensive care unit, where no antibiotic rotation protocol was implemented.

RESULTS

Implementation of an antibiotic rotation protocol in our SICU resulted in a significant increase in the percentage of P. aeruginosa isolates sensitive to ceftazidime (67% in 2002 vs. 92% in 2004, p = 0.002) and piperacillin/tazobactam (78% in 2002 vs. 92% in 2004, p = 0.043). Isolates from the medical intensive care unit did not demonstrate an increase in antimicrobial susceptibility. In fact, the susceptibility of E. coli to piperacillin/tazobactam decreased during this time period (p = 0.047).

CONCLUSIONS

Implementation of an antibiotic rotation protocol in our SICU resulted in overall improvement in the antibiotic susceptibility profile of gram-negative microorganisms relative to our medical intensive care unit, where such a protocol was not used.

Efficacy and safety of cefepime: a systematic review and meta-analysis

Cefepime is a broad-spectrum cephalosporin with enhanced coverage against Gram-positive and Gram-negative bacteria. We did a systematic review of randomised trials that compared cefepime with another beta-lactam antibiotic, alone or with the addition of a non-beta-lactam antibiotic to both study groups. We searched Central, PubMed, Embase, Lilacs, new US Food and Drug Administration drug applications, conference proceedings, and references of the included studies. Two reviewers independently did the search and data extraction. 57 trials were included. All-cause mortality-the primary outcome-was higher with cefepime than other beta-lactams (risk ratio [RR] 1.26 [95% CI 1.08-1.49]). Sensitivity analyses by the trials' methodological quality revealed higher RRs for trials reporting adequate allocation-sequence generation (1.52 [1.20-1.92]) and allocation concealment (1.36 [1.09-1.70]). Baseline risk factors for mortality were similar. No significant differences between groups in treatment failure, superinfection, or adverse events were found. This Review provides evidence and offers possible explanations for increased mortality among patients treated with cefepime in randomised trials.

Relationship of Antimicrobial Control Policies and Hospital and Infection Control Characteristics to Antimicrobial Resistance Rates

• Background Antibiotic misuse and noncompliance with infection control precautions have contributed to increasing levels of antimicrobial resistance in hospitals.

• Objectives To assess the extent to which resistance is monitored in infection control programs and to correlate resistance rates with characteristics of antimicrobial control policies, provider attitudes and practices, and systems-level indicators of implementation of the hand hygiene guideline of the Centers for Disease Control and Prevention.

• MethodsAn on-site survey of intensive care unit staff and infection control directors of 33 hospitals in the United States was conducted. The following data were collected: antimicrobial control policies; rates during the previous 12 months of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and ceftazidime-resistant Klebsiella pneumoniae; an implementation score of systems-level efforts to implement the guideline; staff attitudes toward practice guidelines; and observations of staff hand hygiene. Variables associated with resistance rates were examined for independent effects by using logistic regression.

• ResultsResistance rates for S aureus, enterococci, and K pneumoniae were 52.5%, 18.2%, and 16.0%, respectively. Ten (30.3%) hospitals had an antibiotic control policy. No statistically significant correlation was observed between staff attitudes toward practice guidelines, observed hand hygiene behavior, or having an antibiotic use policy and resistance rates. In logistic regression analysis, higher scores on measures of systems-level efforts to implement the guideline were associated with lower rates of resistant S aureus and enterococci (P=.046).

• Conclusions Organizational-level factors independent of the practices of individual clinicians may be associated with rates of antimicrobial resistance.

How to fight antimicrobial resistance

Antimicrobial misuse results in the development of resistance and superbugs. Over recent decades, resistance has been increasing despite continuing efforts to control it, resulting in increased mortality and cost. Many authorities have proposed local, regional and national guidelines to fight against this phenomenon, and the usefulness of these programmes has been evaluated. Multifaceted intervention seems to be the most efficient method to control antimicrobial resistance. Monitoring of bacterial resistance and antibiotic use is essential, and the methodology has now been homogenized. The implementation of guidelines and infection control measures does not control antimicrobial resistance and needs to be reinforced by associated measures. Educational programmes and rotation policies have not been evaluated sufficiently in the literature. Combination antimicrobial therapy is inefficient in controlling antimicrobial resistance.

Healthcare Epidemiology: Potential Confounding in Evaluating Infection‐Control Interventions in Hospital Settings: Changing Antibiotic Prescription

The colonization dynamics of antibiotic-resistant pathogens in hospital settings are complex, with multiple and continuously interacting variables (e.g., introduction of resistance, infection-control practices, antibiotic use). Quantification of these variables is indispensable in the evaluation of intervention studies, because these variables represent potential confounders. In this article, the complexity of colonization dynamics is described. Through a systematic review, we identified studies that evaluated the modification of antibiotic prescription to reduce antibiotic resistance in intensive care units (n=19), and the extent of confounding-control was determined. Most studies evaluated antimicrobial restriction/substitution (n=12) or antibiotic rotation (n=4). Sixteen studies had a prospective cohort design (before-after), of which 12 were without a control group. Introduction of antibiotic resistance was determined in 10 studies. The relative importance of colonization routes and adherence to infection-control measures were not determined in any study. Therefore, it remains uncertain whether observed changes in the prevalence of antibiotic resistance after intervention were causally related to the intervention. Appropriate choices of study design, primary end point (colonization rates rather than infection rates) and statistical tests, determination of colonization routes, and control of potential confounders are needed to increase validity of intervention studies.

Effect of Antibiotic Heterogeneity on the Development of Infections with Antibiotic-resistant Gram-negative Organisms in a Non-intensive Care Unit Surgical Ward

BACKGROUND

Heterogeneous antibiotic use has been suggested to limit the emergence of resistance, but determining the optimal strategy is difficult.

METHODS

We developed a new strategy, termed "periodic antibiotic monitoring and supervision" (PAMS) program in a non-ICU surgical ward. The 2-year prospective study was divided into a 1-year observation period and a 1-year PAMS period. The use of four major classes of antibiotics in empirical therapy for Gram-negative rod (GNR) infections was supervised. During the PAMS program, recommended, restricted, and off-supervised classes of antibiotics were changed every 3 months according to the usage pattern of the antibiotics in the preceding term.

RESULTS

Cefepime (45.5%) and imipenem/cilastatin (39.4%) were the most common antibiotics of choice during the observation period. The use of these antibiotics decreased significantly during the PAMS period, and that of fluoroquinolones and extended-spectrum penicillin/beta-lactamase inhibitor increased (4.8% vs. 21.4% and 2.4% vs. 21.4%, P<0.01 respectively). Outcome analysis demonstrated a tendency toward reduction in the incidence of resistant GNR infections (P=0.079) and that of Pseudomonas aeruginosa (P=0.053). The incidence of resistant Gram-positive core infections did not decrease. Analysis of antibiotic susceptibility to GNR revealed no significant beneficial results for any antibiotics.

CONCLUSIONS

As significant changes were not observed, the PAMS program is not generally applicable and heterogeneous antibiotic use as a way of reducing infections with resistant GNR in non-ICU surgical wards was not established.

Antimicrobial stewardship programs in health care systems

Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance. With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. The design of antimicrobial management programs should be based on the best current understanding of the relationship between antimicrobial use and resistance. Such programs should be administered by multidisciplinary teams composed of infectious diseases physicians, clinical pharmacists, clinical microbiologists, and infection control practitioners and should be actively supported by hospital administrators. Strategies for changing antimicrobial prescribing behavior include education of prescribers regarding proper antimicrobial usage, creation of an antimicrobial formulary with restricted prescribing of targeted agents, and review of antimicrobial prescribing with feedback to prescribers. Clinical computer systems can aid in the implementation of each of these strategies, especially as expert systems able to provide patient-specific data and suggestions at the point of care. Antibiotic rotation strategies control the prescribing process by scheduled changes of antimicrobial classes used for empirical therapy. When instituting an antimicrobial stewardship program, a hospital should tailor its choice of strategies to its needs and available resources.

Relationships between antimicrobial use and antimicrobial resistance in Gram-negative bacteria causing nosocomial infections from 1991-2003 at a university hospital in Taiwan

This study was conducted to evaluate the relationship between antimicrobial resistance and antimicrobial use in a university hospital in Taiwan. Disk susceptibility data of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens, Proteus spp., Pseudomonas aeruginosa, Acinetobacter spp., Stenotrophomonas maltophilia and other non-fermentative Gram-negative bacilli causing nosocomial infections were evaluated. Data on annual patient-days and annual consumption (defined daily dose (DDD) per 1000 patient-days) of extended-spectrum cephalosporins (cefotaxime, ceftriaxone, ceftazidime, flumoxef, cefepime and cefpirome), β-lactam–β-lactamase inhibitor combinations (ticarcillin/clavulanic acid and piperacillin/tazobactam), carbapenems (imipenem and meropenem), aminoglycosides (amikacin, gentamicin and tobramycin), fluoroquinolones (ciprofloxacin (oral and injectable) and oral levofloxacin and moxifloxacin) from 1991 to 2003 were analysed. Increasing trends of incidences of several of these bacteria causing all nosocomial infections or nosocomial bloodstream infections were noted from 1991 to 2003. The annual patient-days of the hospital significantly increased, from 360 210 in 1991 to 672 676 in 2002 (linear regression analysis, P < 0.05), but slightly decreased in 2003 (629 168) owing to the severe acute respiratory syndrome epidemic in Taiwan. The rise in cefotaxime-resistant or ciprofloxacin-resistant E. coli and meropenem-resistant P. aeruginosa was significantly correlated with increased consumption of extended-spectrum cephalosporins, β-lactam–β-lactamase inhibitor combinations, carbapenems, fluoroquinolones and aminoglycosides (for ciprofloxacin-resistant E. coli and meropenem-resistant P. aeruginosa only) in the hospital (Pearson's correlation coefficient, r > 0.72 (or <−0.72) and P-value < 0.05). Increased ciprofloxacin-resistant K. pneumoniae and meropenem-resistant Acinetobacter spp. was significantly associated with the increased usage of extended-spectrum cephalosporins but not with the other four classes of antibiotics. This 13-year study in a hospital demonstrated significant changes in antimicrobial use, which may have affected antimicrobial resistance in certain Gram-negative bacteria at the hospital.

Nature of gram-negative rod antibiotic resistance during antibiotic rotation

PURPOSE

The aim of this study was to characterize the evolution of gram-negative antibiotic resistance during a study of empiric antibiotic rotation.

METHODS

We showed previously that quarterly rotation of a single antibiotic class is inferior to cycling two antibiotics per quarter for empiric treatment of gram-negative rod (GNR) infections, as evidenced by increased incidence of antibiotic-resistant GNR (rGNR) infections. Resistance patterns were examined by quantifying GNRs resistant to one or more of the following drug classes: Aminoglycosides, cephalosporins, carbapenems, fluoroquinolones, or piperacillin-tazobactam. For all rGNR isolates, the mean number of antibiotic classes to which an organism was resistant was calculated per quarter, as was the number of rGNR species.

RESULTS

Single-antibiotic rotation (SAR) was associated with significant increases in the incidence of piperacillin-tazobactam (p < 0.0005) and cephalosporin (p = 0.003) resistance, reaching nearly 25% and 30% of rGNR isolates respectively, most notably during the quarter of designated cephalosporin use (VI). Multi-drug resistance emerged over time; resistant classes/resistant GNR isolates ranged from 1.2 in the dual-antibiotic rotation (DAR) to 1.9 in the SAR period (p = 0.02). Resistance was evident in an increasing number of unique GNR species. On average, 1.3 species were isolated per month in the DAR period and 3.0/month in the SAR period (p = 0.004), but proportionally, no single GNR species became significantly more resistant across time. Compared to only 5.8% in the DAR period, 29% noncompliance was observed in the SAR, with a six-fold increase in the use of nonscheduled empiric antibiotics due to the presence of an organism resistant to the scheduled rotation drug.

CONCLUSIONS

A single-antibiotic rotation is associated with increased incidence and heterogeneity of resistant GNR isolates, as well as increased multiple-drug-class resistance. The attenuation of resistance observed in the single-antibiotic rotation may reflect the effect of unintended antibiotic heterogeneity driven by increasing resistance to the antibiotic class recommended for use each quarter. This suggests that reliance on a single antibiotic class for empiric treatment of GNR infection exerts sufficient pressure within the environment to encourage the development of diversified resistance, as well as cross-resistance over antibiotic classes, thus narrowing the availability of effective antibiotic treatment.

Sepsis associated with immunosuppressive medications: an evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for sepsis associated with immunosuppressive medications that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Immunosuppressed patients, by definition, are susceptible to a wider spectrum of infectious agents than immunologically normal patients and, thus, require a broader spectrum antimicrobial regimen when they present with sepsis or septic shock. Special expertise managing immunosuppressed patient populations is needed to predict and establish the correct diagnosis and to choose appropriate empiric and specific agents and maximize the likelihood that patients will survive these microbial challenges.

Evaluation of antibiotic use in intensive care units of a tertiary care hospital in Turkey

The object of this study was to evaluate the appropriateness of antibiotic use in relation to diagnosis and bacteriological findings in the intensive care units (ICUs) of a 1100-bed referral and tertiary care hospital with an antibiotic restriction policy in Turkey. Between June and December 2002, patients who received antibiotics in the medical and surgical ICUs were evaluated prospectively. Two infectious diseases (ID) specialists assessed the antibiotics ordered daily. Of the 368 patients admitted to the ICUs, 223 (60.6%) received 440 antibiotics. The most frequently prescribed antibiotics were first-generation cephalosporins (16.1%), third-generation cephalosporins (15.2%), aminoglycosides (12.1%), carbapenems (10.7%) and ampicillin-sulbactam (8.7%). Antibiotic use was inappropriate in 47.3% of antibiotics. ID specialists recommended the use of 47% of all antibiotics. An antibiotic order without an ID consultation was more likely to be inappropriate [odds ratio (OR)=13.2, P<0.001, confidence intervals (CI)=4.4-39.5]. Antibiotics ordered empirically were found to be less appropriate than those ordered with evidence of culture and susceptibility results (OR=3.8, P=0.038, CI=1.1-13.1). Inappropriate antibiotic use was significantly higher in patients who had surgical interventions (OR=3.6, P=0.025, CI=1.2-10.8). Irrational antibiotic use was high for unrestricted antibiotics. In particular, antibiotic use was inappropriate in surgical ICUs. Additional interventions such as postgraduate training programmes and elaboration of local guidelines could be beneficial.

Cycling empirical antimicrobial agents to prevent emergence of antimicrobial-resistant Gram-negative bacteria among intensive care unit patients

OBJECTIVE

To determine the impact of the rotation of antimicrobial agents on the rates of infection, intestinal colonization, and acquisition with antimicrobial-resistant Gram-negative bacteria.

DESIGN

Pre- and postintervention design.

SETTING

A 19-bed, medical intensive care unit.

PATIENTS

Individuals admitted to the study unit for >48 hrs.

INTERVENTIONS

After a 5-month baseline observation period, four classes of antimicrobial agents with Gram-negative activity were cycled at 3- to 4-month intervals for 24 months.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the acquisition rate of antimicrobial resistance among Enterobacteriaceae and Pseudomonas aeruginosa obtained from rectal swab cultures performed on admission, weekly during the patients' stay, and at discharge. Rates and microbiology of nosocomial bloodstream infections and ventilator-associated pneumonia were also compared between baseline and cycling periods. The cycling program resulted in a significant change in prescribing practices; the predominant agent used changed with each cycle. Among study patients who were not already colonized with a resistant organism, the rate of acquisition of enteric colonization with bacteria resistant to any of the target drugs remained stable during the cycling period for P. aeruginosa (relative rate, 0.96; 95% confidence Interval, 0.47-2.16) and Enterobacteriaceae (relative rate, 1.57; 95% confidence interval, 0.80-3.43). Hospital-wide, P. aeruginosa from routine clinical cultures resistant to the target drugs increased during the cycling period. The proportion of Gram-negative bacteria isolated from cases of nosocomial bloodstream infection (29% baseline vs. 26% cycling; p = .11) and ventilator-associated pneumonia (80% vs. 41%; p = .06) did not significantly differ.

CONCLUSIONS

In this study, antimicrobial cycling did not result in a significant change in enteric acquisition of resistant Gram-negative bacteria among intensive care unit patients.

Multi-resistant Gram-negative bacilli: from epidemics to endemics

PURPOSE OF REVIEW

Infections due to multi-drug resistant Gram-negative bacilli represent a worrying situation for the management of hospitalized patients. In addition, these bacteria are increasingly involved in epidemics throughout the world. This review focuses on recent data that may help to understand the emergence and dissemination of multi-drug resistant bacilli and the current trend from epidemic to endemic situations.

RECENT FINDINGS

Well-established clones enhance their resistance phenotype by the acquisition of new resistant genes, via gene capture genetic units (plasmids, transposons or integrons), thus facilitating the co-selective process under different antimicrobial selective pressures and therefore the long-term persistence of organisms in selective environments. Not only resistant bacterial clones are selected, but also their genetic structures carrying resistance genes. Therefore, current epidemiology of multi-drug resistant bacilli is not only focused on bacterial clones but also on any kind of resistance gene capture units. In this scenario a multiclonal population structure of bacterial organisms corresponds to a collection of different strains sharing resistance genes carried by horizontally transferred genetic structures. As different strains tend to prefer different environments, this concept helps understand why the epidemiology of multi-drug resistant Gram-negative bacilli is moving from epidemics to endemics.

SUMMARY

The emergence and spread of multi-drug resistant bacilli in the nosocomial setting should be understood in terms of a complex interplay of bacterial clonality, resistance genes and genetic structures promoting rapid dissemination of antimicrobial resistance. Intervention strategies in the forthcoming scenario should identify existing epidemic and/or endemic situations involving clonal organisms or resistance genes carried by epidemic gene capture units.