Restriction of third-generation cephalosporin use decreases infection-related mortality

Long-term trend of antibiotic use at public health care institutions in northwest China, 2012-20 -- a case study of Gansu Province

BACKGROUND

Over the past 20 years, excessive antibiotic use has led to serious antimicrobial resistance (AMR) worldwide, and the phenomenon is particularly serious in China. To this end, the Chinese health sector took a series of measures to promote rational antibiotic use. In this study, to reveal the impact of policies on antibiotic use, we explored the long-term trend and patterns of antibiotic use at public health care institutions from 2012 to 2020 in northwest China, taking Gansu Province as an example.

METHODS

Antibiotic procurement data were obtained from the provincial centralized bidding procurement (CBP) platform between 2012 and 2020. Antibiotic use was quantified using the Anatomical Therapeutic Chemical (ATC)/defined daily doses (DDD) methodology and standardized using the DDD per 1000 inhabitants per day (DID). Twelve relevant quality indicators were calculated for comparison with the European Surveillance of Antimicrobial Consumption (ESAC) project monitoring results.

RESULTS

Total antibiotic use increased from 18.75 DID to 57.07 DID and then decreased to 19.11 DID, a turning point in 2014. The top three antibiotics used were J01C (beta-lactam antibacterials, penicillins), J01F (macrolides, lincosamides and streptogramins), and J01D (other beta-lactam antibacterials, cephalosporins), accounting for 45.15%, 31.40%, and 11.99% respectively. The oral antibiotics used were approximately 2.5 times the parenteral antibiotics, accounting for 71.81% and 28.19%, respectively. Different use preferences were shown in public hospitals and primary health care centres (PHCs), and the latter accounted for more than half of total use. The absolute use of all classes of antibiotics in Gansu is almost higher than any of the 31 European countries included in the ESAC, but the relative use of some focused antibiotics is lower than theirs.

CONCLUSIONS

The intervention policies of the health department reduced antibiotic use in Gansu Province, but the proportion of broad-spectrum and parenteral antibiotics was still high. It is necessary to further improve the quality of antibiotic prescriptions and pay more attention to the rationality of antibiotic use in PHCs.

Evaluation of a Multidisciplinary Antimicrobial Stewardship Program in a Saudi Critical Care Unit: A Quasi-Experimental Study

Background: Antimicrobial stewardship programs (ASPs) are collaborative efforts to optimize antimicrobial use in healthcare institutions through evidence-based quality improvement strategies. With regard to critically ill patients, appropriate antimicrobial usage is of significance, and any delay in therapy increases their risk of mortality. Therefore, the implementation of structured multidisciplinary ASPs in critical care settings is of the utmost importance to promote the judicious use of antimicrobials.

Methods: This quasi-experimental study evaluating a multidisciplinary ASP in a 20-bed critical care setting was conducted from January 1, 2016 to July 31, 2017. Outcomes were compared nine months before and after ASP implementation. The national antimicrobial stewardship toolkit by Ministry of health was reviewed and the hospital antibiotic prescribing policy was accordingly modified. The antimicrobial stewardship algorithm (Start Smart and Then Focus) and an ASP toolkit were distributed to all intensive care unit staff. Prospective audit and feedback, in addition to prescribing forms for common infectious diseases and education, were the primary antimicrobial strategies.

Results: We found that the mean total monthly antimicrobial consumption measured as defined daily dose per 100 bed days was reduced by 25% (742.86 vs. 555.33; p = 0.110) compared to 7% in the control condition (tracer medications) (35.35 vs. 38.10; p = 0.735). Interestingly, there was a negative impact on cost in the post-intervention phase. Interestingly, the use of intravenous ceftriaxone measured as defined daily dose per 100 bed days was decreased by 82% (94.32 vs. 16.68; p = 0.008), whereas oral levofloxacin use was increased by 84% (26.75 vs. 172.29; p = 0.008) in the intensive care unit.

Conclusion: Overall, involvement of higher administration in multidisciplinary ASP committees, daily audit and feedback by clinical pharmacists and physicians with infectious disease training, continuous educational activities about antimicrobial use and resistance, use of local antimicrobial prescribing guidelines based on up-to-date antibiogram, and support from the intensive care team can optimize antibiotic use in Saudi healthcare institutions.

The Effect of Antibiotic Restriction Programs on Prevalence of Antimicrobial Resistance: A Systematic Review and Meta-Analysis

Background

In hospital settings, restriction of selected classes of antibiotics is usually believed to contribute to containment of resistance development. We performed a systematic review and meta-analysis to assess the effect of restricting the use of specific antibiotic classes on the prevalence of resistant bacterial pathogens.

Methods

We conducted a systematic literature search in Embase and PubMed/OVID MEDLINE. We included studies until June 4, 2020 in which a restrictive antibiotic policy was applied and prevalence of resistance and use of antibiotics were reported. We calculated the overall effect of antimicrobial resistance between postintervention versus preintervention periods using pooled odds ratios (ORs) from a mixed-effects model. We stratified meta-analysis by antibiotic-pathogen combinations. We assessed heterogeneity between studies using the I² statistic and sources of heterogeneity using meta-regression.

Results

We included 15 individual studies with an overall low quality of evidence. In meta-analysis, significant reductions in resistance were only observed with nonfermenters after restricting fluoroquinolones (OR = 0.77, 95% confidence interval [CI] = 0.62–0.97) and piperacillin-tazobactam (OR = 0.81, 95% CI = 0.72–0.92). High degrees of heterogeneity were observed with studies restricting carbapenem (Enterobacterales, I² = 70.8%; nonfermenters, I² = 81.9%), third-generation cephalosporins (nonfermenters, I² = 63.3%), and fluoroquiolones (nonfermenters, I² = 64.0%). Results were comparable when excluding studies with fewer than 50 bacteria. There was no evidence of publication bias for any of the antibiotic-pathogen combinations.

Conclusions

We could not confirm that restricting carbapenems or third-generation cephalosporins leads to decrease in prevalence of antibiotic resistance among Enterobacterales, nonfermenters, or Gram-positive bacteria in hospitalized patients. Nevertheless, reducing fluoroquinolone and piperacilline-tazobactam use may decrease resistance in nonfermenters.

Analysis of Antibiotic Use Patterns and Trends Based on Procurement Data of Healthcare Institutions in Shaanxi Province, Western China, 2015-2018

Overuse of antibiotics has caused a series of global problems, especially in the underdeveloped western regions where healthcare systems are fragile. We used antibiotic procurement data of all healthcare institutions to analyze the total amount, patterns and trends of antibiotic use in Shaanxi Province, western China between 2015 and 2018. Antibiotic utilization was quantified using the standard Anatomical Therapeutic Chemical (ATC)/Defined daily dose (DDD) methodology. The World Health Organization’s “Access, Watch and Reserve” (AWaRe) classification and European Surveillance of Antimicrobial Consumption (ESAC) drug-specific quality indicators were also adopted to evaluate the appropriateness and quality of antibiotic utilization. Overall, antibiotic consumption decreased from 11.20 DID in 2015 to 10.13 DID (DDDs per 1000 inhabitants per day) in 2016, then increased to 12.99 DID in 2018. The top three antibiotic categories consumed in 2018 were J01C (penicillins) 33.58%, J01D (cephalosporins) 29.76%, and J01F (macrolides) 19.14%. Parenteral antibiotics accounted for 27.41% of the total consumption. The largest proportion of antibiotic use was observed in primary healthcare institutions in rural areas, which accounts for 51.67% of total use. Consumption of the Access group, the Watch group, the Reserve group of antibiotics was 40.31%, 42.28% and 0.11%, respectively. Concurrently, the consumption of J01D and the percentage of J01 (DD + DE) (third and fourth generation cephalosporins) were at a poor level according to the evaluation of ESAC quality indicators. The total antibiotic consumption in Shaanxi Province had been on an upward trend, and the patterns of antibiotic use were not justified enough to conclude that it was rational. This is partly because there was high preference for the third and fourth generation cephalosporins and for the Watch group antibiotics.

Role of antimicrobial restrictions in bacterial resistance control: a systematic literature review

BACKGROUND

Antimicrobial stewardship is considered as one of the most fundamental aspects of bacterial resistance control. Among the multitude of initiatives, restrictive strategies have been widely practiced in hospital settings. However, data concerning their potential effectiveness have not been methodically collected and evaluated to date.

AIM

To identify, collect and evaluate the available evidence regarding the impact of restrictive policies on bacterial resistance in hospital settings.

METHODS

A systematic literature review was conducted using the PubMed/Medline, Embase, Global Health and CINAHL Plus databases.

FINDINGS

In total, 5555 papers were retrieved in the search process, and 29 studies were included in the final analysis. There were no randomized studies, and the inherent limitations of the observational designs employed impede the deduction of safe conclusions. Seemingly beneficial interventions encompass the restriction of broad-spectrum cephalosporins in favour of beta-lactam/lactamase inhibitor combinations as well as the restriction of fluoroquinolones. Antimicrobial restrictions might also play a role in the control of vancomycin-resistant enterococci, while carbapenem stewardship in the form of the preferred use of ertapenem did not produce the anticipated results. Complex restrictions are not offered for informative comparative analyses. Hospital-wide policies could perhaps be superior to those confined to high-risk departments. Carbapenem-resistant Acinetobacter baumannii might be difficult to control through solely formulary interventions.

CONCLUSION

The presumably effective restrictive strategies rely mainly on inadequately tested hypotheses and low-quality evidence. Therefore, systematic, high-quality research is needed to confirm and expand comprehension of the subject so that the most successful policies are employed in the field.

Antibiotic Sales in Primary Care in Hubei Province, China: An Analysis of 2012-2017 Procurement Records

The over-use of antibiotics has been identified as a major global challenge, where there is insufficient knowledge about the use of antibiotics in primary healthcare settings, especially at a population level. This study aims to investigate the trends and patterns of antibiotic sales in primary care in Hubei, China over a six-year period from 2012 to 2017. Antibiotic sales were expressed with Defined Daily Doses per 1000 inhabitants per day (DIDs) and compared with European countries using the 12 quality indicators proposed by the scientific advisory board of the European Surveillance of Antimicrobial Consumption (ESAC) project. Antibiotic sales increased from 12.8 DID in 2012 to 15.3 DID in 2013, and then declined afterwards. The most commonly used antibiotics, J01C (beta-lactam antimicrobials, penicillins), accounted for 40.5% of total antibiotic sales. Parenteral administration of antibiotics accounted for over 50% of total antibiotic sales. Total antibiotic sales were almost on a par with the 31 European countries monitored by the ESAC project, but cephalosporin sales were higher than at least three quarters of the compared countries, resulting in a significant higher proportion of third-generation cephalosporin consumption (13.8–19.43%). The relative consumption of Fluoroquinolone (9.26–9.89%) was also higher than at least half of the compared countries. There is a lack of robust evidence to show that antibiotic consumption in primary care is lower in Hubei compared with other countries. The preference of clinicians in China to use broad-spectrum and parenteral antibiotics deserves further study and policy attention.

Initial empirical antibacterial therapy of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is the most frequently occurring nosocomial infection, accounting for considerable morbidity and mortality. Diagnosis can be difficult, creating important therapeutic challenges for intensivists. Early therapy is important in maximizing outcomes, but inappropriate antibacterial treatment has its own risks. A balance needs to be struck between the necessary therapeutic benefits and the negative effects (selection of resistant pathogens, costs, and adverse effects) of antibacterials. Several studies have indicated, in various groups of critically ill patients including those with VAP, that starting treatment with an ineffective antibacterial can increase hospital and intensive care unit length of stay and mortality. When the responsible microorganisms cannot be defined, it may be better to start treatment with a broad-spectrum antibacterial regimen, taking into account individual patient factors and local bacteriology patterns, including antibacterial resistance. As soon as the nature of the pathogen has been defined, the antibacterial agent(s) should be modified accordingly, with the primary aim to reduce the antibacterial spectrum. The optimal duration of therapy is controversial and probably best tailored to the individual patient depending on clinical response and resolution of the factors used to diagnose VAP in that patient. Consultation with an infectious disease specialist may facilitate these therapeutic decisions. With the high morbidity and mortality associated with VAP, prevention is an important issue. General measures include adequate hand hygiene. Physicians must be aware of the risk factors for VAP and of accepted and effective strategies of prevention.

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

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

Antibiotic stewardship programmes in intensive care units: Why, how, and where are they leading us

Antibiotic usage and increasing antimicrobial resistance (AMR) mount significant challenges to patient safety and management of the critically ill on intensive care units (ICU). Antibiotic stewardship programmes (ASPs) aim to optimise appropriate antibiotic treatment whilst minimising antibiotic resistance. Different models of ASP in intensive care setting, include “standard” control of antibiotic prescribing such as “de-escalation strategies”through to interventional approaches utilising biomarker-guided antibiotic prescribing. A systematic review of outcomes related studies for ASPs in an ICU setting was conducted. Forty three studies were identified from MEDLINE between 1996 and 2014. Of 34 non-protocolised studies, [1 randomised control trial (RCT), 22 observational and 11 case series], 29 (85%) were positive with respect to one or more outcome: These were the key outcome of reduced antibiotic use, or ICU length of stay, antibiotic resistance, or prescribing cost burden. Limitations of non-standard antibiotic initiation triggers, patient and antibiotic selection bias or baseline demographic variance were identified. All 9 protocolised studies were RCTs, of which 8 were procalcitonin (PCT) guided antibiotic stop/start interventions. Five studies addressed antibiotic escalation, 3 de-escalation and 1 addressed both. Six studies reported positive outcomes for reduced antibiotic use, ICU length of stay or antibiotic resistance. PCT based ASPs are effective as antibiotic-stop (de-escalation) triggers, but not as an escalation trigger alone. PCT has also been effective in reducing antibiotic usage without worsening morbidity or mortality in ventilator associated pulmonary infection. No study has demonstrated survival benefit of ASP. Ongoing challenges to infectious disease management, reported by the World Health Organisation global report 2014, are high AMR to newer antibiotics, and regional knowledge gaps in AMR surveillance. Improved AMR surveillance data, identifying core aspects of successful ASPs that are transferable, and further well-conducted trials will be necessary if ASPs are to be an effective platform for delivering desired patient outcomes and safety through best antibiotic policy.

Epidemiological interpretation of studies examining the effect of antibiotic usage on resistance

Bacterial resistance to antibiotics is a growing clinical problem and public health threat. Antibiotic use is a known risk factor for the emergence of antibiotic resistance, but demonstrating the causal link between antibiotic use and resistance is challenging. This review describes different study designs for assessing the association between antibiotic use and resistance and discusses strengths and limitations of each. Approaches to measuring antibiotic use and antibiotic resistance are presented. Important methodological issues such as confounding, establishing temporality, and control group selection are examined.

Impact of restriction of cefepime use on the antimicrobial susceptibility of Gram-negative bacilli related to healthcare-associated infections in an orthopedic hospital

Introduction:

In recent decades, antimicrobial resistance has become a public health problem, particularly in cases of healthcare-associated infections. Interaction between antibiotic consumption and resistance development is of particular interest regarding Gram-negative bacilli, whose growing resistance has represented a great challenge.

Objective:

Assess the impact of restriction of cefepime use on antimicrobial susceptibility among the Gram-negative bacilli (GNB) most frequently involved in healthcare-associated infections (HAI).

Methods:

Data relating to hospital occupancy and mortality rates, incidence of HAI, incidence of GNB as causative agents of HAI, antimicrobial consumption at the hospital and antimicrobial susceptibility of GNB related to HAI were compared between two periods: a 24-month period preceding restriction of cefepime use and a 24-month period subsequent to this restriction.

Results:

There was a significant drop in cefepime consumption after its restriction. Susceptibility of Acinetobacter baumanii improved relating to gentamicin, but it worsened in relation to imipenem, subsequent to this restriction. For Pseudomonas aeruginosa, there was no change in antimicrobial susceptibility. For Klebsiella pneumoniae and Enterobacter spp, there were improvements in susceptibility relating to ciprofloxacin.

Conclusion:

Restriction of cefepime use had a positive impact on K. pneumoniae and Enterobacter spp, given that after this restriction, their susceptibilities to ciprofloxacin improved. However, for A. baumanii, the impact was negative, given the worsening of susceptibility to imipenem.

Impact of antimicrobial stewardship in critical care: a systematic review

OBJECTIVES

To evaluate the current state of evidence for antimicrobial stewardship interventions in the critical care unit.

METHODS

We performed a systematic search of OVID MEDLINE, Embase and Cochrane electronic databases from 1996-2010. Studies were included if they involved any experimental intervention to improve antimicrobial utilization in the critical care setting.

RESULTS

Thirty-eight studies met the inclusion criteria, of which 24 met our quality inclusion criteria. The quality of research was poor, with only 3 randomized controlled trials, 3 interrupted time series and 18 (75%) uncontrolled before-and-after studies. We identified six intervention types: studies of antibiotic restriction or pre-approval (six studies); formal infectious diseases physician consultation (five); implementation of guidelines or protocols for de-escalation (two); guidelines for antibiotic prophylaxis or treatment in intensive care (two); formal reassessment of antibiotics on a pre-specified day of therapy (three); and implementation of computer-assisted decision support (six). Stewardship interventions were associated with reductions in antimicrobial utilization (11%-38% defined daily doses/1000 patient-days), lower total antimicrobial costs (US$ 5-10/patient-day), shorter average duration of antibiotic therapy, less inappropriate use and fewer antibiotic adverse events. Stewardship interventions beyond 6 months were associated with reductions in antimicrobial resistance rates, although this differed by drug-pathogen combination. Antibiotic stewardship was not associated with increases in nosocomial infection rates, length of stay or mortality.

CONCLUSIONS

More rigorous research is needed, but available evidence suggests that antimicrobial stewardship is associated with improved antimicrobial utilization in the intensive care unit, with corresponding improvements in antimicrobial resistance and adverse events, and without compromise of short-term clinical outcomes.

Impact of restriction of third generation cephalosporins on the burden of third generation cephalosporin resistant K. pneumoniae and E. coli in an ICU

OBJECTIVE

To test whether a reduction of third generation cephalosporin (3GC) use has a sustainable positive impact on the high endemic prevalence of 3GC resistant K. pneumoniae and E. coli.

DESIGN

Segmented regression analysis of interrupted time series was used to analyse antibiotic consumption and resistance data 30 months before and 30 after the intervention.

SETTING

Surgical intensive care unit (ICU) with 16-bed unit in a teaching hospital.

INTERVENTION

In July 2004, 3GCs were switched to piperacillin in combination with a beta-lactamase-inhibitor as standard therapy for peritonitis and other intraabdominal infections.

RESULTS

Segmented regression analysis showed that the intervention achieved a significant and sustainable decrease in the use of 3GCs of -110.2 daily defined doses (DDD)/1,000 pd. 3GC use decreased from a level of 178.9 DDD/1,000 pd before to 68.7 DDD/1,000 pd after the intervention. The intervention resulted in a mean estimated reduction in total antibiotic use of 27%. Piperacillin/tazobactam showed a significant increase in level of 64.4 DDD/1,000 pd, and continued to increase by 2.3 DDD/1,000 pd per month after the intervention. The intervention was not associated with a significant change in the resistance densities of 3GC resistant K. pneumoniae and E. coli.

CONCLUSION

Reducing 3GCs does not necessarily impact positively on the resistance situation in the ICU setting. Likewise, replacing piperacillin with beta-lactamase inhibitor might provide a selection pressure on 3GC resistant E. coli and K. pneumoniae. To improve resistance, it might not be sufficient to restrict interventions to a risk area.

Control of extended-spectrum {beta}-lactamase-producing Klebsiella pneumoniae using a computer-assisted management program to restrict third-generation cephalosporin use

OBJECTIVES

The aim of this study was to evaluate the control of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and antimicrobial resistance through a computerized antibiotic control program.

METHODS

An ambidirectional intervention study was conducted at a 750-bed university hospital in Korea from February 2004 to April 2006. In November 2004, hospital-wide restriction of third-generation cephalosporin use was integrated into a pre-existing computerized antibiotic prescription program that included an approval system for 15 antimicrobials. The proportions of ESBL-producing K. pneumoniae and other multidrug-resistant clinical isolates were compared during three phases (9 months per phase): Phase I (pre-intervention), Phase II (intensive-intervention) and Phase III (maintenance).

RESULTS

Third-generation cephalosporin use decreased significantly from 103.2 to 84.9 antibiotic use density (AUD, defined daily dose/1000 patient-days) between Phase I and Phase II (P< 0.05), whereas use of carbapenems and beta-lactam/beta-lactamase inhibitors increased from 14.5 to 18.2 AUD and from 53.3 to 62.6 AUD, respectively. The proportion of ESBL-producing K. pneumoniae isolates increased significantly from 8.1% (47/578) in Phase I to 32.0% (188/587) in Phase II, and then decreased significantly to 20.6% (97/470) in Phase III (P < 0.05). In addition, the proportions of imipenem- or piperacillin/tazobactam-resistant Pseudomonas aeruginosa and Acinetobacter baumannii isolates decreased significantly over the same period (P < 0.05).

CONCLUSIONS

The computerized antibiotic control program appears to be an effective tool for modifying antibiotic consumption, which may in turn prevent the spread of resistant pathogens.

Impact of an antibiotic restriction policy on the antibiotic resistance patterns of Gram-negative microorganisms in an Intensive Care Unit in Greece

The purpose of this study was to investigate the influence of an antibiotic policy programme based on restriction of the empirical use of fluoroquinolones and ceftazidime on the susceptibilities of Gram-negative microorganisms in a general Intensive Care Unit (ICU). The epidemiology of infections caused by the predominant ICU pathogens, i.e. Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae, and their resistance patterns as well as antibiotic consumption were recorded for a 6-month period. An antibiotic restriction policy including ceftazidime and quinolones was applied. After an 18-month period of protocol application, the same parameters were recorded for another 6-month period. Consumption of restricted and overall antibiotics was reduced by 92.5% and 55.4%, respectively. Susceptibilities to ciprofloxacin of the three predominant infection-causing Gram-negative bacilli were significantly increased. Ceftazidime showed an increase in susceptibility only for P. aeruginosa. Similar rates of infectious episodes were recorded in the two periods and no differences were observed either in overall mortality or in ICU ecology as expressed by the type of microorganisms implicated in colonisation and/or infection. The reported data suggest that an antibiotic restriction policy can significantly reduce antimicrobial consumption and antimicrobial resistance rates, although the latter effect can be also influenced by the prevalent resistance mechanisms and the prevalence of imported resistance.

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.

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.

Hospital-Based Strategies for Combating Resistance

Selective pressures generated by the indiscriminate use of beta-lactam antibiotics have resulted in increased bacterial resistance across all beta-lactams classes. In particular, the use of third-generation cephalosporins has been associated with the emergence of extended-spectrum beta-lactamase-producing and AmpC beta-lactamase-producing Enterobacteriaceae and vancomycin-resistant enterococci. Conversely, beta-lactams (e.g., cefepime, piperacillin-tazobactam, and ampicillin-sulbactam) have not demonstrated such strong selective pressures. Chief among institutional strategies to control outbreaks of multidrug-resistant bacteria are infection-control measures and interventional programs designed to minimize the use of antimicrobial agents that are associated with strong relationships between use and resistance. Successful programs include antimicrobial stewardship programs (prospective audit and feedback), formulary interventions (therapeutic substitutions), formulary restrictions, and vigilant infection control. Fourth-generation cephalosporins, such as cefepime, have proven to be useful substitutes for third-generation cephalosporins, as a part of an overall strategy to minimize the selection and impact of antimicrobial-resistant organisms in hospital settings.

Selection of resistance during sequential use of preferential antibiotic classes

OBJECTIVE

To determine the effect of antibiotic class pressure on the susceptibility of bacteria during sequential periods of antibiotic homogeneity.

DESIGN AND SETTING

Prospective study in a mixed ICU with three separated subunits of eight, eight, and ten beds.

PATIENTS AND PARTICIPANTS

The study examined the 1,721 patients with a length of stay longer than 2 days.

INTERVENTIONS

Three different antibiotic regimens were used sequentially over 2 years as first-choice empirical treatment: cephalosporins, fluoroquinolone, or a penicillin-beta-lactamase inhibitor combination. Each regimen was applied for 8 months in each subunits of the ICU, using "latin square" design.

RESULTS

We treated 731 infections in 546 patients (32% of patients staying more than 48 h). There were 25.5 ICU-acquired infections per 1,000 patient-days. Infecting pathogens and colonizing bacteria were found in 2,739 samples from 1,666 patients (96.8%). No significant change in global antibiotic susceptibility was observed over time. However, a decrease in the susceptibility of several species was observed for antibiotics used as the first-line therapy in the unit. Selection pressure of antibiotics and occurrence of resistance during treatment was documented within an 8-month rotation period.

CONCLUSIONS

Antibiotic use for periods of several months induces bacterial resistance in common pathogens.

Cephalosporins in clinical development

Bacterial resistance to established classes of antibiotics in clinical use is continuing to increase, making the need for new agents that can be used to treat the newly multi-drug resistant organisms steadily more urgent. Cephalosporins have been a successful group of antibiotics since they were first introduced to combat drug-resistant organisms, including staphylococci. The history of cephalosporins has emphasised an improvement of their stability towards beta-lactamases, thus expanding their spectrum of activity against important Gram-negative pathogens. New cephalosporins that have potent activity against multi-resistant Gram-positive bacteria, including methicillin-resistant staphylococci and penicillin-resistant pneumococci have recently entered clinical development. At least two of these, BAL-5788 and S-3578, also have Gram-negative activity, which is comparable to that of the third-and fourth-generation cephalosporins, making them broad-spectrum agents that could be used in hospital infections where methicillin-resistant staphylococci is likely to be present.

The therapeutic challenge of Gram-negative sepsis: Prolonging the lifespan of a scarce resource

Mortality from severe bacterial sepsis remains high. The pathogenesis involves production of pro and anti-inflammatory cytokines which mediate: neutrophil adhesion to the endothelium, diffuse capillary leak, disseminated intravascular coagulation, vasodilatation and mitochondrial dysfunction, all of which culminate in microcirculatory failure. Therapy is multifaceted. As described in 'the surviving sepsis guidelines', many therapeutic interventions, such as early goal-directed resuscitation, low dose intravenous steroids, strict glucose control, recombinant activated protein C and ventilation according to ARDS- net criteria are critical to survival. However appropriate empiric antibiotic therapy initiated early is pivotal. Empiric therapy should be designed with regard to the bacterial epidemiology within the unit and the aim should be to optimise outcome while yet attempting to reduce the potential for resistance development. Antibiotic therapy for resistant organisms consists of the carbapenems, including ertapenem for ESBL's, cefepime, piperacillin/tazobactam and, on occasion, the Gram-negative quinolones, ciprofloxacin and levofloxacin. Consideration should be given to the possibility of 'collateral damage', where overuse of an antibiotic predisposes to multi-drug resistance. Antibiotics should be limited, where possible, to those organisms that are pathogens and not colonisers and should be discontinued if sepsis is not confirmed or there is rapid resolution of clinical indicators of sepsis. De-escalation strategies should be consistently employed and the duration of therapy should be tailored to clinical response. Continuation beyond 8 days is generally detrimental in terms of the potential for superinfection with resistant organisms. Failure of response necessitates, initially, a re-evaluation of source control and obsessive culturing of likely sites of sepsis prior to random antibiotic changes.

Third generation cephalosporin use in a tertiary hospital in Port of Spain, Trinidad: need for an antibiotic policy

Background

Tertiary care hospitals are a potential source for development and spread of bacterial resistance being in the loop to receive outpatients and referrals from community nursing homes and hospitals. The liberal use of third-generation cephalosporins (3GCs) in these hospitals has been associated with the emergence of extended-spectrum beta- lactamases (ESBLs) presenting concerns for bacterial resistance in therapeutics. We studied the 3GC utilization in a tertiary care teaching hospital, in warded patients (medical, surgical, gynaecology, orthopedic) prescribed these drugs.

Methods

Clinical data of patients (≥ 13 years) admitted to the General Hospital, Port of Spain (POSGH) from January to June 2000, and who had received 3GCs based on the Pharmacy records were studied. The Sanford Antibiotic Guide 2000, was used to determine appropriateness of therapy. The agency which procures drugs for the Ministry of Health supplied the cost of drugs.

Results

The prevalence rate of use of 3GCs was 9.5 per 1000 admissions and was higher in surgical and gynecological admissions (21/1000) compared with medical and orthopedic (8 /1000) services (p < 0.05). Ceftriaxone was the most frequently used 3GC. Sixty-nine (36%) patients without clinical evidence of infection received 3Gcs and prescribing was based on therapeutic recommendations in 4% of patients. At least 62% of all prescriptions were inappropriate with significant associations for patients from gynaecology (p < 0.003), empirical prescribing (p < 0.48), patients with undetermined infection sites (p < 0.007), and for single drug use compared with multiple antibiotics (p < 0.001). Treatment was twice as costly when prescribing was inappropriate

Conclusions

There is extensive inappropriate 3GC utilization in tertiary care in Trinidad. We recommend hospital laboratories undertake continuous surveillance of antibiotic resistance patterns so that appropriate changes in prescribing guidelines can be developed and implemented. Though guidelines for rational antibiotic use were developed they have not been re-visited or encouraged, suggesting urgent antibiotic review of the hospital formulary and instituting an infection control team. Monitoring antibiotic use with microbiology laboratory support can promote rational drug utilization, cut costs, halt inappropriate 3GC prescribing, and delay the emergence of resistant organisms. An ongoing antibiotic peer audit is suggested.