Experience with a hospital-wide outbreak of vancomycin-resistant enterococci

Evaluation of ceftriaxone use in the medical ward of Halibet National Referral and teaching hospital in 2017 in Asmara, Eritrea: a cross sectional retrospective study

BACKGROUND

Antibiotic resistance due to overuse of antimicrobials is an issue that has been of concern to many health institutions and society in general. Resistant infections have high impact in low income countries since they can't afford more recent and expensive antibiotics. Studies that evaluate antibiotic use in hospitals are scarce in Eritrea. Ceftriaxone is commonly available in Halibet National Referral and teaching hospital (HNRTH). Resistance to this antibiotic would have a great impact on the hospital since there is no other available third generation cephalosporin or higher classes of antibiotics.

METHOD

A retrospective cross sectional design was used to evaluate the use of ceftriaxone in patients admitted to the medical ward in 2017. Clinical card number of inpatients who took ceftriaxone was extracted from the database of the Satellite Pharmacy Department of HNRTH and collected using a standardized data collection form. A descriptive analysis was employed and the Statistical package for social sciences (SPSS), version 20 was used for analysis.

RESULTS

A total of 120 patients were taking ceftriaxone for various indications. There were 55 (50.5%) males and 54 (49.5%) females. 59.8% of the patients were treated in the range of 0-7 days. The mean age was 56 (SD: 20.7). On average patients were under treatment for 6 days. The proportion of patients taking ceftriaxone was 11.43% out of all admissions in the medical ward. One, two or three antibiotics were co-prescribed with ceftriaxone in 39.4%. The most commonly co-prescribed antibiotic was gentamycin, accounting for 16.4% of the co-administered antibiotics. The most common indications for ceftriaxone were pneumonia, sepsis, TB, and CHF. Ceftriaxone therapy was appropriate in 30 (27.5%) cases and 68 (62.4%) cases were inappropriate in any of the four parameters of assessment used.

CONCLUSION

Inappropriate use of ceftriaxone was found to be high in the hospital. This calls for establishment of hospital and national guidelines of antimicrobial treatment. Moreover drug restriction and antibiotic stewardship implementation in the hospital should be sought to prolong the lives of important drugs like ceftriaxone.

Eradication of a Large Outbreak of a Single Strain of vanB Vancomycin-ResistantEnterococcus faeciumat a Major Australian Teaching Hospital

Objective:

To demonstrate that nosocomial transmission of vancomycin-resistant enterococci (VRE) can be terminated and endemicity prevented despite widespread dissemination of an epidemic strain in a large tertiary-care referral hospital.

Interventions:

Two months after the index case was detected in the intensive care unit, 68 patients became either infected or colonized with an epidemic strain of vanB vancomycin-resistantEnterococcus faeciumdespite standard infection control procedures. The following additional interventions were then introduced to control the outbreak: (1) formation of a VRE executive group; (2) rapid laboratory identification (30 to 48 hours) using culture and polymerase chain reaction detection ofvanA andvanBresistance genes; (3) mass screening of all hospitalized patients with isolation of carriers and cohorting of contacts; (4) environmental screening and increased cleaning; (5) electronic flagging of medical records of contacts; and (6) antibiotic restrictions (third-generation cephalosporins and vancomycin).

Results:

A total of 19,658 patient and 24,396 environmental swabs were processed between July and December 2001. One hundred sixty-nine patients in 23 wards were colonized with a single strain of vanB vancomycin-resistantE. faecium.Introducing additional control measures rapidly brought the outbreak under control. Hospital-wide screening found 39 previously unidentified colonized patients, with only 7 more nonsegregat-ed patients being detected in the next 2 months. The outbreak was terminated within 3 months at a cost of $2.7 million (Australian dollars).

Conclusion:

Despite widespread dissemination of VRE in a large acute care facility, eradication was achievable by a well-resourced, coordinated, multifaceted approach and was in accordance with good clinical governance.

Outcomes Associated With Vancomycin-Resistant Enterococci: A Meta-Analysis

Background:

Because patients with vancomycin-resistantEnterococcusbacteremia (VREB) usually have a higher severity of illness, it has been unclear whether VREB is worse than vancomycin-susceptibleEnterococcusbacteremia (VSEB).

Methods:

Data on morbidity and case fatality rates and costs were pooled from studies comparing VREB and VSEB, identified by Medline (January 1986 to April 2002) and meeting abstracts. Heterogeneity across studies was assessed with contingency table chi-square. Multivariate analyses (MVAs) controlling for other predictors were evaluated.

Results:

Thirteen studies compared case-fatality rates of VREB and VSEB. VREB case fatality was significantly higher (48.9% vs 19%; RR, 2.57; CI95, 2.27 to 2.91; attributable mortality = 30%). Five studies compared VREB with VSEB when bacteremia was the direct cause of death; VREB case fatality was significantly higher (39.1% vs 21.8%; RR, 1.79; CI95, 1.28 to 2.5; attributable mortality = 17%). Four MVAs found significant increases in case-fatality rates (OR 2.10 to 4.0), 3 showed trends toward increase (OR, 1.74 to 3.34 with wide confidence intervals), and 3 with low statistical power found no difference. VREB recurred in 16.9% versus 3.7% with VSEB (P< .0001). Three studies reported significant increases in LOS, costs, or both with VREB.

Conclusion:

Most studies have had inadequate sample size, inadequate adjustment for other predictors of adverse outcomes, or both, but available data suggest that VREB is associated with higher recurrence, mortality, and excess costs than VSEB including multiple studies adjusting for severity of illness.

Vancomycin-resistant Enterococcus – A Review From a Singapore Perspective

Introduction: Vancomycin-resistant enterococcus (VRE) can cause serious infections in vulnerable, immunocompromised patients. Materials and Methods: In this article, we summarise current data on epidemiology, detection, treatment and prevention of VRE. Results: VRE was first isolated in Singapore in 1994 and until 2004 was only sporadically encountered in our public hospitals. After 2 outbreaks in 2004 and in 2005, VRE has become established in our healthcare institutions. Multiple studies have shown that VRE spreads mainly via contaminated hands, cloths and portable equipment carried by healthcare workers. Conclusions: Only a comprehensive programme (consisting of active surveillance, isolation of colonised/infected patients, strict adherence to proper infection control practices and anti-microbial stewardship) can limit the spread of these organisms. In addition to monitoring the compliance with traditional infection control measures, new strategies that merit consideration include pre-emptive isolation of patients in high-risk units and molecular techniques for the detection of VRE. Keywords: Antibiotic resistance, Infection control, Outbreaks, Surveillance

Is Antibiotic Cycling the Answer to Preventing the Emergence of Bacterial Resistance in the Intensive Care Unit?

Antibiotic resistance has emerged as an important determinant of mortality for patients in the intensive care unit (ICU) setting. This is largely due to the increasing presence of pathogenic microorganisms with resistance to existing antibiotic agents, resulting in the administration of inappropriate treatment. Escalating antibiotic resistance has also been associated with greater overall health care costs, as a result of prolonged hospitalizations and convalescence associated with failure of antibiotic treatment, the need to develop new antibiotic agents, and the implementation of broader infection control and public health interventions aimed at curbing the spread of antibiotic-resistant pathogens. Antibiotic cycling has been advocated as a tool to reduce the occurrence of antibiotic resistance, especially in the ICU setting. Unfortunately, the cumulative evidence to date suggests that antibiotic cycling has limited efficacy for preventing antibiotic resistance. Nevertheless, a strategy whereby multiple or all classes of antibiotics are available for use (i.e., antibiotic heterogeneity) can be part of a broader effort aimed at curtailing antibiotic resistance within ICUs. Such efforts should be routine, given the limited availability of new antibiotic drug classes for the foreseeable future.

The intensive care unit as a research laboratory: developing strategies to prevent antimicrobial resistance

OBJECTIVE

To assemble the available clinical data on the prevention of antimicrobial resistance in the intensive care unit (ICU) setting.

DATA SOURCE

A MEDLINE database search and references from identified articles were employed to obtain the literature relating to the prevention of antimicrobial resistance in the ICU.

CONCLUSIONS

The ICU presents a unique environment for the conduct of clinical research. The closed physical space with centralized patient management and efficient data recovery allows important clinical questions to be evaluated in a timely manner. Antimicrobial resistance has emerged as an important determinant of mortality for patients in the ICU. Additionally, there is currently a limited pipeline of new agents for the treatment of emerging bacteria with new resistance genes that pose an increasing threat to the ICU patient. Effective strategies for the prevention of antimicrobial resistance within ICUs are available and should be implemented aggressively. These strategies can be divided into non-pharmacologic infection- control strategies (e.g., routine hand hygiene, infection-specific prevention protocols) and antibiotic management strategies (e.g., shorter courses of appropriate antibiotics, narrowing of the antimicrobial spectrum on the basis of culture results). Additional studies conducted in ICUs are needed urgently to identify the optimal approaches for the management of antibiotics in order to balance the need for efficacy with the ability to minimize resistance.

The influence of antibiotic use on the occurrence of vancomycin-resistant enterococci

BACKGROUND

Several studies have documented the influence of antibiotic selective pressure, mainly from the use of glycopeptides, third-generation cephalosporins, quinolones and lincosamides, on the frequency of vancomycin-resistant enterococci (VRE) occurrence in hospitals. The aim of this study was to evaluate the relationship between VRE occurrence and antibiotic use in the Department of Hemato-Oncology of the Teaching Hospital in Olomouc (DHO), Czech Republic, over a 6-year period under standard and unchanged hygienic and epidemiological conditions.

METHODS

During the period of 1998-2003, Enterococcus sp. strains and VRE were isolated by standard methods from clinical samples taken from DHO in-patients. The frequency of VRE occurrence was expressed as the number of isolated strains per 100 bed-days/year. DHO antibiotic consumption data were processed according to the anatomical therapeutic chemical (ATC)/defined daily dose (DDD) system valid in 2003 and expressed in defined daily dose per 100 bed-days (DDD/100 bed-days) for each year of the period.

RESULTS

Since 1998, the occurrence of VRE decreased significantly (from 0.28 to 0.17 VRE/100 bed-days in 2001). Between 2001 and 2003, a significant (P < 0.05) increase from 0.17 to 0.38 was observed. The antibiotic use decreased from 205.2 in 1998 to 161.0 DDD/100 bed-days in 1999 and after an increase in 2001 (to 181.8 DDD/100 bed-days) it remained relatively stable. A significant decrease was observed in third-generation cephalosporins and quinolones (from 29.5 to 9.7 and from 42.2 to 30.2 DDD/100 bed-days respectively) between 1998 and 1999. In 2002-2003, the use of third-generation cephalosporins and glycopeptides increased substantially (from 10.1 to 13.9 and from 11.3 to 15.2 DDD/100 bed-days respectively). The Pearson correlation value was significantly positive (P < 0.05) for VRE occurrence and the use of glycopeptides and third-generation cephalosporins.

CONCLUSIONS

While our study confirms the effect of use of glycopeptides and third-generation cephalosporins on occurrence of VRE, no influence of quinolones and lincosamides over the 6-year period was shown.

Antibiotics and gastrointestinal colonization by vancomycin-resistant enterococci

Although several classes of antimicrobial agents have been associated with colonization or infection with glycopeptide-resistant enterococci (GRE) in individual clinical studies, the agents most commonly implicated are extended-spectrum cephalosporins and compounds with potent activity against anaerobic bacteria, including ticarcillin-clavulanic acid. In some clinical studies, formulary alterations designed to minimize the use of extended-spectrum cephalosporins or ticarcillin-clavulanic acid have resulted in significant decreases in colonization and infection by GRE. Experimental data using a mouse model of GRE gastrointestinal colonization indicate that persistence of high-level GRE colonization of the mouse gastrointestinal tract is promoted by exposure to agents with potent activity against anaerobic bacteria, suggesting that reduction of competing flora is the major factor leading to persistence of high-level colonization. One study performed in humans is consistent with this model and suggests that high levels of colonization may promote spread of resistant organisms in the nosocomial setting. Establishing colonization with GRE in uncolonized mice correlates with exposure to agents that are (a) secreted into the bile in significant concentrations and (b) have negligible activity against the colonizing enterococcal strain. Differences between piperacillin-tazobactam and ceftriaxone in the establishment model can be attributed directly to differences in their anti-enterococcal activity. Modification of antimicrobial prescribing practices may play an important role in facilitating successful infection control efforts to limit GRE in the nosocomial setting.

Strategies to prevent antimicrobial resistance in the intensive care unit

OBJECTIVE

To assemble the available clinical data for the prevention of antimicrobial resistance into practical recommendations for clinicians.

DATA SOURCE

A Medline database and references from identified articles were employed to perform a literature search relating to the prevention of antimicrobial resistance.

CONCLUSIONS

Antimicrobial resistance has emerged as an important determinant of mortality for patients in the intensive care unit. This is largely due to the increasing presence of pathogenic microorganisms with resistance to existing antimicrobial agents, resulting in the administration of inappropriate treatment. Effective strategies for the prevention of antimicrobial resistance within intensive care units are available and should be aggressively implemented. These strategies can be divided into nonpharmacologic infection control strategies (e.g., routine hand hygiene, implementation of infection-specific prevention protocols) and antibiotic management strategies (e.g., shorter courses of appropriate antibiotic treatment, narrowing of antimicrobial spectrum based on culture results). Increasing current efforts aimed at the prevention of antimicrobial resistance is especially important given the limited availability of new antimicrobial drug classes for the foreseeable future.

Bench-to-bedside review: antimicrobial utilization strategies aimed at preventing the emergence of bacterial resistance in the intensive care unit

Antimicrobial resistance has emerged as one of the most important issues complicating the management of critically ill patients with infection. This is largely due to the increasing presence of pathogenic microorganisms with resistance to existing antimicrobial agents resulting in the administration of inappropriate treatment. Effective strategies for the prevention of antimicrobial resistance within intensive care units are available and should be aggressively implemented. The importance of preventing antimicrobial resistance is magnified by the limited availability of new antimicrobial drug classes for the foreseeable future.

Emerging bacterial pathogens: a consensus of the scientific data and the risk for development of multiple organ dysfunction syndrome

Antibiotic resistance in the hospital setting is continuing to increase, particularly in intensive care units (ICUs) and other areas of the hospital such as oncology units, where the use of empiric broad-spectrum antibiotics is common. The problem of antibiotic resistance is also compounded in the immunocompromised patient. Multi-drug resistance is common among both Gram-positive and -negative bacteria, and becoming more prevalent among fungi (yeast). Two major antibiotic-resistant pathogens include extended-spectrum beta-lactamase producing Klebsiella pneumoniae (ESBL-KP) and vancomycin-resistant enterococci (VRE). When infections occur with ESBL-KP, a carbapenem antibiotic is usually the drug of choice. When infection occurs with VRE, specific therapy is bacteriostatic, and the clinician may have to rely on empirically selected antibiotics or combinations of antibiotics to achieve a positive outcome. Two newly-approved agents, linezolid and quinupristin/dalfopristin can be used to treat infections caused by resistant gram-positive cocci, but the latter is approved for use against VR-E. faecium. Risk factors for the development of ESBL-KP include the use of extended-spectrum cephalosporins such as ceftazidime. Risk factors for the development of VRE include inappropriate use of vancomycin, extended-spectrum cephalosporins, and antianaerobic drug therapy such as clindamycin. Several institutions have documented a reduction in one or both of these resistant pathogens following a decrease in the use of extended-spectrum cephalosporins combined with the increased use of extended-spectrum penicillins/beta-lactamase inhibitor combinations, such as piperacillin/tazobactam, for the empiric therapy of infections. For VRE, a reduction in the inappropriate use of vancomycin is also an important interventional strategy along with improved infection control practice.

Failure to develop vancomycin-resistant Enterococcus with oral vancomycin treatment of Clostridium difficile

OBJECTIVE

Oral vancomycin therapy has been a risk factor for turning culture positive for vancomycin-resistant Enterococcus (VRE). VRE colonization status was reviewed for all patients who received oral vancomycin and underwent prospective cultures.

METHODS

Data were extracted from the medical records of all patients receiving oral vancomycin between August 1995 and February 2001 regarding history, hospital course, and perirectal VRE cultures. Hospital policy required contact isolation for patients receiving oral vancomycin until colonization with VRE was excluded.

RESULTS

Twenty-six courses of oral vancomycin were given to 22 patients. VRE colonization status after completion of therapy was evaluated for 23 courses in 20 (91%) of these patients. None of these patients became VRE culture positive during a median follow-up of 18 days (range, 9 to 39 days), with a median duration of treatment of 10 days (range, 3 to 58 days), and with a median total dose of 6,500 mg (range, 1,250 to 29,000 mg). All patients received other antibiotics within 30 days prior to therapy with oral vancomycin, during therapy with oral vancomycin, or both; 95% had received anti-anaerobic therapy and 35% had received parenteral vancomycin.

CONCLUSIONS

Even when other risk factors were present, no patient receiving oral vancomycin at our facility subsequently became culture positive for VRE. This suggests that oral vancomycin therapy or other antibiotic use, including anti-anaerobic therapy, may not be a significant independent risk factor for turning culture positive for VRE among patients not previously exposed to the microbe.

Antibacterial screening of plants used in Iranian folkloric medicine

Fifty methanolic plant extracts belonging to 44 plant species of 33 families finding use in Iranian folkloric medicine were screened for antibacterial activity. Thirty samples, including 28 species in 20 families, had antibacterial activity against at least on one of the bacteria. Among the active plants, 32.6% were active against G(-), 62% against G(+), and 47.3% against both G(-) and G(+) bacteria. Dianthus coryophyllus was active against all tested G(-) and G(+) bacteria except Micrococcus luteus. Most susceptible G(-) bacteria were Klebsiella pneumoniae and Bordetella bronchiseptica and least susceptible G(-) bacterium was Escherichia coli. In G(+) bacteria, most and least susceptible were Staphylococcus aureus and M. luteus, respectively. The least MIC, as 0.62 mg/ml, belonged to Myrtus communis seeds against S. aureus, Bacillus cereus and B. bronchiseptica, and to Terminalia chebula ripe seeds against S. aureus.

Clonality among ampicillin-resistant Enterococcus faecium isolates in Sweden and relationship with ciprofloxacin resistance

OBJECTIVE

To investigate clonal relationships in a nationwide sample of human Enterococcus faecium isolates.

METHODS

Biochemical fingerprinting (PhP (PhenePlate) typing) was used to compare 180 fecal ampicillin-resistant E. faecium (ARE) isolates with 169 matched fecal ampicillin-susceptible E. faecium (ASE) isolates from patients in 23 hospitals, collected in 1998, and to study 39 fecal ARE isolates from non-hospitalized individuals collected in 1998, and five ARE and 29 ASE isolates from the early 1990s. Representative ARE and ASE isolates were subjected to pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA and sequencing of the regions encoding the fluoroquinolone targets of the enzymes GyrA and ParC.

RESULTS

Both PhP and PFGE results showed a higher homogeneity among ARE than among ASE isolates (P < 0.001). One PhP type (FMSE1) comprised 73% of the hospital ARE isolates (53% of ARE isolates from non-hospitalized individuals, and four of five ARE isolates from the early 1990s), but only 1% of the ASE isolates. PFGE of the hospital E. faecium isolates revealed that 23 of the 25 ARE isolates and one of the 22 ASE isolates were of one dominating type. High-level resistance to ciprofloxacin (MIC > 16 mg/L) was present in 91% of ARE isolates, whereas only low-level resistance (MIC 4-16 mg/L; 35% of isolates) was found among ASE isolates. One mutation in parC (codon 80) and one of two mutations in gyrA (codons 83 or 87) were detected in all ARE isolates tested with high-level ciprofloxacin resistance, but were lacking in ARE and ASE isolates with low-level ciprofloxacin resistance.

CONCLUSION

Most ARE isolates in Sweden were clonally related. High-level ciprofloxacin resistance was found in ARE isolates of PhP type FMSE1 as well as in other PhP types, but never in ASE isolates.

Control of endemic vancomycin-resistant Enterococcus among inpatients at a university hospital

We sought to determine the ability of surveillance cultures and isolation of vancomycin-resistant Enterococcus (VRE)-colonized patients to control nosocomial VRE infection and colonization during a 5-year period (November 1994 through October 1999). During this period, VRE colonization was limited to 0.82% of admissions. The incidence of VRE infection was 0.12 cases per 1000 patient-days (attack rate, 0.07%). Colonized patients were first identified by surveillance (95%) or routine clinical cultures (5%); 14% of colonized patients had a positive clinical culture a median of 15 days after a positive surveillance culture. Ten percent of colonized patients were identified by surveillance at the time of transfer from another health care facility. Identification of these colonized patients was associated with reduction from a peak incidence rate of 2.07% to a rate of 1.25% and stabilization at this lower level. The use of surveillance cultures to identify and isolate patients with asymptomatic colonization can provide sustained control of the spread of VRE within a health care facility.

SHEA guideline for preventing nosocomial transmission of multidrug-resistant strains of Staphylococcus aureus and enterococcus

BACKGROUND

Infection control programs were created three decades ago to control antibiotic-resistant healthcare-associated infections, but there has been little evidence of control in most facilities. After long, steady increases of MRSA and VRE infections in NNIS System hospitals, the Society for Healthcare Epidemiology of America (SHEA) Board of Directors made reducing antibiotic-resistant infections a strategic SHEA goal in January 2000. After 2 more years without improvement, a SHEA task force was appointed to draft this evidence-based guideline on preventing nosocomial transmission of such pathogens, focusing on the two considered most out of control: MRSA and VRE.

METHODS

Medline searches were conducted spanning 1966 to 2002. Pertinent abstracts of unpublished studies providing sufficient data were included.

RESULTS

Frequent antibiotic therapy in healthcare settings provides a selective advantage for resistant flora, but patients with MRSA or VRE usually acquire it via spread. The CDC has long-recommended contact precautions for patients colonized or infected with such pathogens. Most facilities have required this as policy, but have not actively identified colonized patients with surveillance cultures, leaving most colonized patients undetected and unisolated. Many studies have shown control of endemic and/or epidemic MRSA and VRE infections using surveillance cultures and contact precautions, demonstrating consistency of evidence, high strength of association, reversibility, a dose gradient, and specificity for control with this approach. Adjunctive control measures are also discussed.

CONCLUSION

Active surveillance cultures are essential to identify the reservoir for spread of MRSA and VRE infections and make control possible using the CDC's long-recommended contact precautions.

Vancomycin-resistant enterococci: a road map on how to prevent the emergence and transmission of antimicrobial resistance

Nosocomial acquisition of microorganisms resistant to multiple antibiotics represents a threat to patient safety. Here we review the mechanisms that have allowed highly resistant strains belonging to the Enterococcus genus to proliferate within our health-care institutions. These mechanisms indicate that decreasing the prevalence of resistant organisms requires active surveillance, adherence to vigorous isolation, hand hygiene and environmental decontamination measures, and effective antibiotic stewardship. We suggest how to tailor such a complex, multidisciplinary program to the needs of a particular health-care setting so as to maximize cost-effectiveness.

Overview of resistant gram-positive pathogens in the surgical patient

Staphylococci and enterococci are the most common pathogens in surgical-site and bloodstream infections. The emergence of drug resistance among these gram-positive bacteria thus poses a substantial threat to patients with surgical infections. Resistance to methicillin/oxacillin is frequently observed in Staphylococcus aureus isolates and is often accompanied by multidrug resistance. Vancomycin is usually the treatment of choice for infections caused by methicillin-resistant S. aureus (MRSA), so the recent appearance of S. aureus isolated with intermediate sensitivity to vancomycin is cause for concern. Vancomycin resistance has already appeared in most species of enterococci. Infections caused by vancomycin-resistant enterococci (VRE) are associated with increased mortality compared to infections caused by vancomycin-sensitive isolates. Measures for preventing vancomycin resistance include reducing the use of vancomycin and other agents that appear to be associated with VRE, including third-generation cephalosporins and anti-anaerobic drugs. Third-generation cephalosporins have also been implicated in the increased prevalence of MRSA infections. Prudent use of existing antibiotics is an essential strategy for combating the rising tide of drug-resistant gram-positive pathogens.

Decreased antimicrobial resistance following changes in antibiotic use

The widespread use of perioperative antibiotic prophylaxis makes surgical procedures an important component of overall antibiotic use. Attempts to reduce costs and limit the emergence of resistance among pathogenic bacteria by altering antibiotic use must therefore encompass surgical prophylaxis. Several recent reports have linked the use of third-generation cephalosporins with beta-lactam resistance in gram-negative bacteria and with vancomycin resistance in Enterococcus. Fortunately, susceptibility can often be restored by replacing third-generation cephalosporins with drugs that are less likely to foster resistance; a penicillin/beta-lactamase inhibitor combination is often a suitable substitute. An antibiotic resistance management program can effect the type of changes in antimicrobial use necessary to forestall or reverse an outbreak of resistant pathogens. Such a plan was implemented at Methodist Hospital, Indianapolis, Indiana, in 1995. Piperacillin/tazobactam (in combination with an aminoglycoside) was added to the formulary, primarily as empiric therapy, replacing the use of third-generation cephalosporins such as ceftazidime. Following this change, the prevalences of vancomycin-resistant Enterococcus, methicillin-resistant Staphylococcus aureus, and other resistant gram-negative bacilli were all reduced. As this effective formulary change shows, appropriate changes in antibiotic drug, dosage, and administration route can limit the emergence of resistance and ultimately lower costs.

Impact of a web-based antimicrobial approval system on broad-spectrum cephalosporin use at a teaching hospital

OBJECTIVE

To achieve sustained improvement in use of cefotaxime and ceftriaxone (CEFX) in a major teaching hospital, as measured against national antibiotic guidelines.

DESIGN AND SETTING

Pre- and post-intervention survey of CEFX use in the Royal Melbourne Hospital, a tertiary hospital in Melbourne, Victoria.

INTERVENTION

Web-based antimicrobial approval system linked to national antibiotic guidelines was developed by a multidisciplinary team and implemented in March 2001.

MAIN OUTCOME MEASURES

Change in rate of CEFX use (defined daily doses [DDDs] per 1000 acute occupied bed days) over 8 months pre- and 15 months post-intervention; concordance of indication for CEFX with national antibiotic guidelines pre- and post-intervention.

RESULTS

CEFX use decreased from a mean of 38.3 DDDs/1000 bed days pre-intervention to 15.9, 18.7 and 21.2 DDDs/1000 bed days at 1, 4 and 15 months post-intervention. Concordance with national antibiotic guidelines rose from 25% of courses pre-intervention to 51% within 5 months post-intervention (P < 0.002). Gentamicin use also increased, from a mean of 30.0 to 48.3 DDDs/1000 bed days (P = 0.0001).

CONCLUSION

The web-based antimicrobial approval system achieved a sustained reduction in CEFX use over 15 months as well as increased prescribing concordance with antibiotic guidelines. It has potential for linking to electronic prescribing and for wider use for other drugs, as well as for research into the epidemiology of antibiotic use.

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

OBJECTIVE

To determine the effect of restriction of third-generation cephalosporin use on antibiotic resistance and the outcome of patients with infection.

DESIGN

A prospective, before-after comparative study.

SETTING

A general intensive care unit with 14 beds at a university-affiliated teaching hospital.

PATIENTS

All patients admitted to the intensive care unit within 2 yrs.

INTERVENTIONS

A new antibiotic treatment strategy was implemented during phase II. All patients with confirmed or suspected Gram-negative bacterial infections were treated mainly with antibiotics other than third-generation cephalosporins.

MEASUREMENTS AND MAIN RESULTS

Antibiotic resistance among common Gram-negative bacilli and infection-related hospital mortality during phase I were compared with phase II. A 26.6% reduction in third-generation cephalosporin use (from 168.2 +/- 48.0 to 123.5 +/- 39.3 g/month, p =.021), accompanied by a 277.7% increase in cefepime use (from 10.3 +/- 19.2 to 38.9 +/- 31.7 g/month, p =.014) occurred in phase II compared with phase I. This was accompanied by a significant decrease in reduced susceptibility of Gram-negative bacilli to third-generation cephalosporins (p <.05), mainly because of the improved susceptibility of Escherichia coli and Klebsiella species (p <.05). Infection-related hospital mortality was significantly lower in phase II (19.3% vs. 36.3%, p =.014). Multiple logistic regression analysis demonstrated lower respiratory tract infection, the status of immunocompromise, and continuous veno-venous hemofiltration as independent risk factors for infection-related hospital mortality (p <.05), whereas infection with E. coli or Klebsiella species (p =.039) and restriction of third-generation cephalosporin use (p =.025) were associated with a significantly lower mortality rate.

CONCLUSIONS

Restriction of third-generation cephalosporin use may improve the antibiotic susceptibility and reduce infection-related hospital mortality in critically ill patients.

Changes in the prevalence of vancomycin-resistant enterococci in response to antimicrobial formulary interventions: impact of progressive restrictions on use of vancomycin and third-generation cephalosporins

This study sought to assess the impact of restricting use of vancomycin and third-generation cephalosporins on vancomycin-resistant enterococci (VRE) prevalence. All clinical enterococcal isolates identified at a large academic medical center during a 10-year period were analyzed. Changes in VRE prevalence after sequential restrictions on use of vancomycin and third-generation cephalosporins were evaluated. The correlation between antibiotic use and VRE prevalence was also investigated. Vancomycin use initially decreased by 23.9% but returned to preintervention levels by the end of the study. Third-generation cephalosporin use decreased by 85.8%. However, VRE prevalence increased steadily from 17.4% to 29.6% during the 10-year period (P<.001). Clindamycin use was significantly correlated with VRE prevalence. Restricting the use of vancomycin and third-generations cephalosporins had little impact on VRE prevalence. The association between clindamycin use and the prevalence of VRE suggests that restriction of this and perhaps other antianaerobic agents might be an important component of future antimicrobial interventions.

Species prevalence and antibacterial resistance of enterococci isolated in Kuwait hospitals

This study investigated the species prevalence and antibacterial resistance among enterococci isolated in Kuwait hospitals. They consisted of 415 isolates of Enterococcus faecalis (85.3 %), Enterococcus faecium (7.7 %), Enterococcus casseliflavus (4.0 %), Enterococcus avium (1.2 %), Enterococcus durans (1.0 %), Enterococcus gallinarium (0.5 %) and Enterococcus bovis (0.2 %) isolated from urine (36.6 %), blood (10.4 %), wound swabs (11.0 %), stool samples (12.0 %), high vaginal swabs (9.0 %), endocervical swabs (3.0 %) and miscellaneous sources (18.0 %). All of them were susceptible to linezolid. Fifty-two (12.5 %) isolates were ampicillin resistant but none of them produced beta-lactamase. They were resistant to erythromycin (63.3 %), tetracycline (60.5 %), ciprofloxacin (40.0 %), chloramphenicol (28.0 %), vancomycin (2.6 %), and teicoplanin (2.6 %). Fourteen, 19 and 20 % of them expressed high-level resistance to gentamicin, kanamycin and streptomycin, respectively. All of the vancomycin-resistant strains carried the vanA phenotype and genotype. There was no evidence of clonal spread of the vancomycin-resistant isolates.

Current implications of drug resistance in spinal cord injury

A 54-yr-old man with C6 quadriplegia and a neurogenic bowel and bladder was evaluated for clearance of a urinary tract infection after treatment for organisms susceptible to the antibiotics used, and an organism resistant to all antibiotics on the panel grew on the initial follow-up urine culture. Multidrug-resistant organisms present increasing challenges and risks in the management of the neurogenic bladder in patients with spinal cord injury. In an effort to control and reduce the impact and risk associated with these organisms, management methods of the neurogenic bladder and infection control policies should be adjusted according to guidelines from the Centers for Disease Control and related research; such policies could include surveillance for multidrug-resistant organisms and isolation of patients who test positive for these organisms.

Cost-effectiveness of perirectal surveillance cultures for controlling vancomycin-resistant Enterococcus

BACKGROUND

Several hospitals opting not to use active surveillance cultures to identify carriers of vancomycin-resistant Enterococcus (VRE) have reported that adoption of other parts of the Centers for Disease Control and Prevention guideline for controlling VRE has had little to no impact. Because use of surveillance cultures and contact isolation controlled a large outbreak at this hospital, their costs were estimated for comparison with the excess costs of VRE bacteremias occurring at a higher rate at a hospital not employing these measures.

SETTING

Two university hospitals.

METHODS

Inpatients deemed high risk for VRE acquisition at this hospital underwent weekly perirectal surveillance cultures. Estimated costs of cultures and resulting isolation during a 2-year period were compared with the estimated excess costs of more frequent VRE bacteremias at another hospital of similar size and complexity not using surveillance cultures to control spread throughout the hospital.

RESULTS

Of 54,052 patients admitted, 10,400 had perirectal swabs taken. Cultures and isolation cost an estimated $253,099. VRE culture positivity was limited to 193 (0.38%) and VRE bacteremia to 1 (0.002%) as compared with 29 bacteremias at the comparison hospital. The estimated attributable cost of VRE bacteremia at the comparison hospital of $761,320 exceeded the cost of the control program at this hospital by threefold.

CONCLUSIONS

The excess costs of VRE bacteremia may justify the costs of preventive measures. The costs of VRE infections at other body sites, of deaths from untreatable infections, and of dissemination of genes for vancomycin resistance also help to justify the costs of implementing an effective control program.

Antibiotic resistance of enterococci isolated at a teaching hospital in Kuwait

Enterococci isolated in a teaching hospital were studied for their resistance to different antibiotics. Minimum inhibitory concentrations to high-level aminoglycosides and glycopeptide antibiotics were determined by agar dilution and E-test methods respectively. Genes encoding aminoglycoside-modifying enzymes were detected by the polymerase chain reaction (PCR). 195 enterococci were isolated from urines (54.3%), wounds (16.4%), blood (10.2%), and miscellaneous sources (18.9%). They consisted of E. faecalis (88.7%), E. faecium (9.2%), E. casseliflavus (1.5%) and E. bovis (0.5%). None of the enterococci produced penicillinase but 3.5% of them were resistant to ampicillin. They were also resistant to high-level gentamicin (15.9%), kanamycin (22.0%), streptomycin (21.0%), tetracycline (65.1%), erythromycin (62.6%), ciprofloxacin (36.1%), chloramphenicol (26.1%), vancomycin (3.0%) and teicoplanin (2.0%). Most of the high-level aminoglycoside-resistant isolates contained genes coding the bifunctional aminoglycoside modifying enzymes AAC(6')-APH(2"), APH(3') and ANT(6') but not the ANT(4') enzyme. The results demonstrated a low prevalence of vancomycin resistance among Enterococci in this hospital.

Ceftriaxone and cefotaxime use in Victorian hospitals

OBJECTIVE

To determine patterns of use of ceftriaxone and cefotaxime (CEFX) in Victorian hospitals and to identify areas for improvement.

DESIGN, PATIENTS AND SETTING

A concurrent, observational evaluation of CEFX use in patients commencing a course of these drugs between 8 and 14 September, 1999, in 51 Victorian hospitals.

MAIN OUTCOME MEASURES

Proportion of patients treated with CEFX; indications; duration of use; concordance with recommendations of national antibiotic guidelines (Therapeutic guidelines: antibiotic, 10th edition [AG10]).

RESULTS

671 patients were treated with CEFX. The overall rate of use was 43 patients per 1000 inpatient separations. Treatment of respiratory tract infection accounted for 352 patients (52%) and surgical prophylaxis for 99 patients (15%). Treatment of skin/soft tissue, urinary tract and gastrointestinal tract infections accounted for about 7% of patients each. The median duration of CEFX courses was 3.0 days. The overall rate of concordance with indications recommended in AG10 was 27%. The rate of concordance for empirical treatment of respiratory tract infection was 24%. Of the 195 patients treated empirically with CEFX for community-acquired respiratory tract infection and assessed as non-concordant, 64% did not have radiological evidence of pneumonia, and a further 30% did not fulfill the criteria for severe pneumonia. All courses given for surgical prophylaxis were non-concordant.

CONCLUSIONS

CEFX is widely used in Victorian hospitals, mostly to treat lower respiratory tract infection and in surgical prophylaxis of infection. The rate of concordance with AG10 is low. Potential areas for intervention include empirical treatment of respiratory tract infection and use in surgical prophylaxis.

Effectiveness of a multifaceted infection control policy in reducing vancomycin usage and vancomycin-resistant enterococci at a tertiary care cancer centre

We undertook a prospective cohort study to evaluate the role of a multifaceted infection control policy including the use of a "vancomycin order form," in decreasing the transmission of vancomycin-resistant enterococci (VRE). In January 1997, a multifaceted infection-control policy was implemented amongst patients admitted to the M. D. Anderson Cancer Center in whom neutropenic fever developed or who were found to be colonized or infected with VRE. As part of this programme, we initiated the use of a vancomycin order form to reduce the use of empirical vancomycin. The total incidence of VRE infections declined from 0.437/1000 patient days in 1996-97 to 0.229/1000 patient days in 1998-99 (P=0.008). The VRE bloodstream infections declined from 0.338/1000 patient days in 1996-97 to 0.181/1000 patient days in 1998-99 (P=0.027). Empiric vancomycin use decreased from 416 g/1000 patient days in 1996-97 to 208 g/1000 patient days in 1998-99 (P<0.001), resulting in a decreased vancomycin cost from $2561 US dollars/1000 patient days in 1996-97 to $1195 US dollars/1000 patient days in 1997-98 (P<0.001). We conclude that a multifaceted infection control policy incorporating the use of a vancomycin order form can effectively decrease the use of empirical vancomycin and can play a role in limiting the spread of VRE in an endemic setting.

Antibiotic resistance patterns of bacterial isolates from blood in San Francisco County, California, 1996-1999

Countywide antibiotic resistance patterns may provide additional information from that obtained from national sampling or individual hospitals. We reviewed susceptibility patterns of selected bacterial strains isolated from blood in San Francisco County from January 1996 to March 1999. We found substantial hospital-to-hospital variability in proportional resistance to antibiotics in multiple organisms. This variability was not correlated with hospital indices such as number of intensive care unit or total beds, annual admissions, or average length of stay. We also found a significant increase in methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and proportional resistance to multiple antipseudomonal antibiotics. We describe the utility, difficulties, and limitations of countywide surveillance.

Risk factors for colonization with vancomycin-resistant enterococci in a Melbourne hospital

OBJECTIVE

To determine risk factors for colonization with vancomycin-resistant enterococci (VRE) in a hospital outbreak.

DESIGN

Outbreak investigation and case-control study.

SETTING

A referral teaching hospital in Melbourne, Australia.

PARTICIPANTS

Cases were inpatients colonized (with or without clinical disease) with VRE between July 26 and November 28, 1998; controls were hospitalized patients without VRE.

METHODS

Five cases of VRE were identified between July 26 and November 8, 1998, by growth of VRE from various sites. Active case finding by cultures of rectal swabs from patients surveyed in wards was commenced on July 26, after the first isolate of VRE.

RESULTS

There were 19 cases and 66 controls. All the VRE identified were vanB, and all were Enterococcus faecium. One molecular type predominated (18/19 cases). In a logistic-regression model, being on the same ward as a VRE case was the highest risk factor (odds ratio [OR], 82; 95% confidence interval [CI95], 5.7-1,176; P=.001). Having more than five antibiotics (OR, 11.9; CI95 1.1-129.6; P<.05), use of metronidazole (OR, 10.9; CI95, 1.7-69.8; P=.01), and being a medical patient (OR, 8.1; CI95, 1.4-47.6; P<.05) also were significant. Intensive care unit admission was associated with decreased risk (OR, 0.1; CI95, 0.01-0.8; P<.05).

CONCLUSION

Our findings are consistent with an acute hospital outbreak. Monitoring and control of antibiotic use, particularly metronidazole, may reduce VRE in our hospital. Ongoing surveillance and staff education also are necessary.

Can antibiotic-resistant nosocomial infections be controlled?

Three decades ago infection-control programmes were created to control antibiotic-resistant nosocomial infections, but numbers of these infections have continued to increase, leading many to question whether control is feasible. Meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci were major problems during the 1990s. Many hospitals have tried antibiotic control but with limited efficacy against these pathogens. Studies of antibiotic restriction, substitution, and cycling have been promising, but more definitive data are needed. Increased compliance with hand hygiene would help but is unlikely to control this problem alone as a result of frequent contamination of other surfaces even when hands are cleansed and high transmission rates when hand hygiene is neglected. For 17 years, the Centers for Disease Control and Prevention have recommended contact precautions for preventing nosocomial spread of important antibiotic-resistant pathogens. Many studies confirm that this approach works when sufficient active-surveillance cultures are undertaken to detect the reservoir for spread. However, most healthcare facilities have not yet tried this approach.

Antimicrobial management measures to limit resistance: A process-based conceptual framework

To curb the trend toward increasingly resistant microorganisms, we must at least ensure that antibiotics are used in accordance with the best available scientific evidence. Here we review the control and streamlining measures aimed at optimizing the use of antibiotics, placing an emphasis on their demonstrated effectiveness in the intensive care unit environment. Because of their wide variety, the measures have been organized along the process of choosing, dosing, delivering, and then adjusting the initial antibiotics according to the culture results. By clarifying the range of options available, this process-based conceptual framework assists in best adapting a creative mixture of control measures to a particular healthcare system. The framework also facilitates the overview of a proposed multidisciplinary antibiotic management program, thereby helping to secure the administrative and local provider support necessary for its implementation and continued improvement.

Is there a role for antibiotic cycling in the intensive care unit?

Antibiotic resistance of bacterial pathogens has emerged as one of the most important issues facing critical care practitioners. Resistance of many commonly encountered bacterial species is increasing and has been associated with greater administration of inadequate antimicrobial therapy to patients within intensive care units. This has resulted in greater patient morbidity, higher mortality rates, and increased healthcare costs. Methods to reduce antimicrobial resistance have focused on increasing adherence to infection control practices and improving antibiotic utilization. Antibiotic cycling is a strategy to reduce antimicrobial resistance by withdrawing an antibiotic or antibiotic class from use and subsequently reintroducing it at a later point in time. The main goal of cycling is to allow resistance rates for specific antibiotics to decrease, or at least remain stable, when their use is periodically eliminated from the intensive care unit.

Surveillance strategies and impact of vancomycin-resistant enterococcal colonization and infection in critically ill patients

OBJECTIVE

To determine the optimal site and frequency for vancomycin-resistant enterococci (VRE) surveillance to minimize the number of days of VRE colonization before identification and subsequent isolation.

SUMMARY BACKGROUND DATA

The increasing prevalence of VRE and the limited therapeutic options for its treatment demand early identification of colonization to prevent transmission.

METHODS

The authors conducted a 3-month prospective observational study in medical and surgical intensive care unit (ICU) patients with a stay of 3 days or more. Oropharyngeal and rectal swabs, tracheal and gastric aspirates, and urine specimens were cultured for VRE on admission to the ICU and twice weekly until discharge.

RESULTS

Of 117 evaluable patients, 23 (20%) were colonized by VRE. Twelve patients (10%) had VRE infection. Of nine patients who developed infections after ICU admission, eight were colonized before infection. The rectum was the first site of colonization in 92% of patients, and positive rectal cultures preceded 89% of infections acquired in the ICU. This was supported by strain delineations using pulsed-field gel electrophoresis. Twice-weekly rectal surveillance alone identified 93% of the maximal estimated VRE-related patient-days; weekly or admission-only surveillance was less effective. As a test for future VRE infection, rectal surveillance culture twice weekly had a negative predictive value of 99%, a positive predictive value of 44%, and a relative risk for infection of 34.

CONCLUSIONS

Twice-weekly rectal VRE surveillance of critically ill patients is an effective strategy for early identification of colonized patients at increased risk for VRE transmission, infection, and death.

Emergence of vancomycin-resistant enterococci

Vancomycin and ampicillin resistance in clinical Enterococcus faecium strains has developed in the past decade. Failure to adhere to strict infection control to prevent the spread of these pathogens has been well established. New data implicate the use of specific classes of antimicrobial agents in the spread of vancomycin-resistant enterococci (VRE). Extended-spectrum cephalosporins and drugs with potent activity against anaerobic bacteria may promote infection and colonization with VRE and may exert different effects on the initial establishment and persistence of high-density colonization. Control of VRE will require better understanding of the mechanisms by which different classes of drugs promote gastrointestinal colonization.

Optimizing antibiotic therapy in the intensive care unit setting

Antibiotics are one of the most common therapies administered in the intensive care unit setting. In addition to treating infections, antibiotic use contributes to the emergence of resistance among pathogenic microorganisms. Therefore, avoiding unnecessary antibiotic use and optimizing the administration of antimicrobial agents will help to improve patient outcomes while minimizing further pressures for resistance. This review will present several strategies aimed at achieving optimal use of antimicrobial agents. It is important to note that each intensive care unit should have a program in place which monitors antibiotic utilization and its effectiveness. Only in this way can the impact of interventions aimed at improving antibiotic use (e.g. antibiotic rotation, de-escalation therapy) be evaluated at the local level.

Inadequate treatment of nosocomial infections is associated with certain empiric antibiotic choices

OBJECTIVE

The purpose of this study was to determine the impact of scheduled changes of antibiotic classes, used for the empirical treatment of suspected or documented Gram-negative bacterial infections, on the occurrence of inadequate antimicrobial treatment of nosocomial infections.

DESIGN

Prospective observational study.

SETTING

Medical (19-bed) and surgical (18-bed) intensive care units in an urban teaching hospital.

PATIENTS

A total of 3,668 patients requiring intensive care unit admission were prospectively evaluated during three consecutive time periods.

INTERVENTIONS

During each time period, one antibiotic class was selected for the empirical treatment of Gram-negative bacterial infections as follows: time period 1 (baseline period) (1,323 patients), ceftazidime; time period 2 (1,243 patients), ciprofloxacin; and time period 3 (1,102 patients), cefepime.

MEASUREMENTS AND MAIN RESULTS

The overall administration of inadequate antimicrobial treatment for nosocomial infections decreased during the course of the study (6.1%, 4.7%, and 4.5%; p = .15). This was primarily because of a statistically significant decrease in the administration of inadequate antibiotic treatment for Gram-negative bacterial infections (4.4%, 2.1%, and 1.6%; p < .001). There were no statistically significant differences in the overall hospital mortality rate among the three time periods (15.6%, 16.4%, and 16.2%; p = .828) despite a significant increase in severity of illness as measured with Acute Physiology and Chronic Health Evaluation (APACHE) II scores (15.3 +/- 7.6, 15.7 +/- 8.0, and 20.7 +/- 8.6; p < .001). The hospital mortality rate decreased significantly during time period 3 (20.6%) compared with time period 1 (28.4%; p < .001) and time period 2 (29.5%; p < .001) for patients with an APACHE II score > or = 15.

CONCLUSIONS

These data suggest that scheduled changes of antibiotic classes for the empirical treatment of Gram-negative bacterial infections can reduce the occurrence of inadequate antibiotic treatment for nosocomial infections. Reducing inadequate antibiotic administration may improve the outcomes of critically ill patients with APACHE II scores > or = 15.

Experience of vancomycin-resistant enterococci in a children's hospital

Vancomycin resistant enterococci (VRE) are increasingly important nosocomial pathogens. This paper describes our experience of the epidemiology and clinical impact of VRE in the two years since the occurrence of our first case of VRE infection. Following introduction of surveillance, gastrointestinal colonization with VRE was detected in 38.3% of Haematology/Oncology and 11.1% of Hepatology/Gastroenterology patients, but in only 2.3% of children in the Paediatric Intensive Care and 1.5% of children in the Renal Unit. Only five patients with gastrointestinal colonization subsequently developed clinical infection with VRE, giving an annual incidence of 7.5%. A further six children were colonized at extra-intestinal sites. Twelve children had clinical infections with VRE, of whom three (25%) died. Contamination of bedspaces was found in association with 2/3 (66.7%) children with extraintestinal colonization and 5/7 (71.4%) children with clinical infections, compared with 6/28 (21.4%) cases of gastrointestinal colonization. In the latter group, bedspace contamination was usually associated with widespread contamination of the ward with VRE and may have been the cause rather than the result of patients acquiring VRE. Originally we employed control measures based closely on the North American HICPAC guidelines, but our control strategy has since evolved in response to epidemiological and clinical observations.