Control of vancomycin-resistant enterococci: it is important, it is possible, and it is cost-effective

Emergence of Vancomycin-Resistant Enterococci in San Francisco Bay Area Hospitals During 1994 to 1998

Objective:

To determine the magnitude of van-comycin-resistant enterococci (VRE) in three counties in the San Francisco Bay area.

Design:

Active laboratory-based surveillance for VRE from January 1995 through December 1996 and a laboratory-based and hospital-based questionnaire survey for 1993 to 1994 and 1997 to 1998.

Setting:

All 33 general acute care hospitals in three counties in the San Francisco Bay area.

Participants:

Laboratories and infection control professionals serving these hospitals, and staff of the California Emerging Infections Program.

Results:

The number of hospitals reporting 1 or more patient clinical VRE isolates was 1 (3%) in 1993, 7 (21%) in 1994, 31 (94%) in 1995, and 33 (100%) in 1996 to 1998. The number of patient isolates increased from 1 in 1993 to 24 in 1994, 176 in 1995,429 in 1996, 730 in 1997, and 864 in 1998. Most VRE isolates in 1995 and 1996 were from urine and were not associated with serious clinical disease. However, the number of isolates from blood increased from 9 (6% of total) in 1995 to 44 (12% of the total) in 1996, 90 (14%) in 1997, and 100 (13%) in 1998.

Conclusions:

Our data document the rapid emergence and increase of VRE in all hospitals in three counties in the San Francisco Bay area during 1994 to 1998. Infection control measures for VRE together with antibiotic utilization programs should be implemented to limit further spread.

A Cost-Benefit Analysis of Gown Use in Controlling Vancomycin-ResistantEnterococcusTransmission Is It Worth the Price?

Objective:

To determine the net benefit and costs associated with gown use in preventing transmission of van-comycin-resistantEnterococcus(VRE).

Design:

A cost-benefit analysis measuring the net benefit of gowns was performed. Benefits, defined as averted costs from reduced VRE colonization and infection, were estimated using a matched cohort study. Data sources included a step-down cost allocation system, hospital informatics, and microbiology databases.

Setting:

The medical intensive care unit (MICU) at Barnes-Jewish Hospital, St. Louis, Missouri.

Patients:

Patients admitted to the MICU for more than 24 hours from July 1, 1997, to December 31, 1999.

Interventions:

Alternating periods when all healthcare workers and visitors were required to wear gowns and gloves versus gloves alone on entry to the rooms of patients colonized or infected with VRE.

Results:

On base-case analysis, 58 VRE cases were averted with gown use during 18 months. The annual net benefit of the gown policy was $419,346 and the cost per case averted of VRE was $1,897. The analysis was most sensitive to the level of VRE transmission.

Conclusions:

Infection control policies (eg, gown use) initially increase the cost of health services delivery. However, such policies can be cost saving by averting nosocomial infections and the associated costs of treatment. The cost savings to the hospital plus the benefits to patients and their families of avoiding nosocomial infections make effective infection control policies a good investment.

Duration of colonization and risk factors for prolonged carriage of vancomycin-resistant enterococci after discharge from the hospital

BACKGROUND

There are no available studies on the duration and risk factors of vancomycin-resistant enterococci (VRE) carriage after hospital discharge. In this study we investigated the duration of colonization with VRE and the risk factors for prolonged carriage in the outpatient clinic after discharge from the hospital.

METHODS

The study took place from January 2008 to September 2009. Patients were included if they were identified as persistent VRE carriers by follow-up rectal swab or stool cultures in the outpatient setting, after discharge from the hospital without clearance of VRE. The probability of culture positivity and clearance was analyzed from the discharge date. Cox regression was performed to determine the risk factors for prolonged carriage. VRE clearance was defined as VRE-negative rectal (or stool) cultures on at least three consecutive occasions a minimum of 1 week apart.

RESULTS

One hundred twenty-seven patients were included in this study. Follow-up cultures were conducted for a median of 8.86 weeks (range 1-90 weeks) after hospital discharge. The median duration of culture positivity of VRE was 5.57 weeks (range 0-50.14 weeks). Ninety-six out of 127 patients (75.6%) showed the first negative culture result at a median time of 4.86 weeks (range 0-66 weeks) after discharge. Among these patients, 15 were lost to follow-up after the first negative culture and eight were lost after the second negative culture. Sixty-eight patients (53.5%) were confirmed to have clearance of VRE during follow-up in the outpatient clinic. The median time to clearance after discharge was 8.86 weeks (range 2-90 weeks). In the cleared cases, the median time to the first negative VRE culture result was 4.71 weeks (range 0-66 weeks). Ninety percent of patients showed the first negative culture result at 25 weeks and VRE clearance at 30 weeks after discharge. Surgery or antibiotic use during admission (p = 0.048 and p = 0.001, respectively), dialysis (p = 0.046), and discharge to a nursing home or other health care institution (p = 0.025) were independently associated with prolonged colonization with VRE.

CONCLUSIONS

The median duration of VRE colonization was 5.57 weeks after hospital discharge. In the cases with clearance during follow-up, the median time to clearance after discharge was 8.86 weeks. Risk factors for prolonged carriage were surgery, antibiotic use during admission, dialysis, and discharge to a nursing home or other health care institution. Therefore, patients with these risk factors should be managed more carefully to prevent transmission of VRE in the outpatient clinic.

Contamination of renal patients' hospital chart covers with vancomycin-- resistant enterococci: Handle with care

BACKGROUND

Vancomycin--resistant enterococci (VRE) have been increasingly associated with patients with renal failure attending large metropolitan teaching hospitals. Monash Medical Center has been following guidelines issued by the Department of Human Services to reduce the spread of VRE, but unfortunately this has had limited impact, especially in the renal unit. In an attempt to investigate the causes of the sustained VRE prevalence in the renal unit, this study sought to determine if renal patient chart covers were contaminated with VRE and if there was any genetic similarity to patient VRE isolates.

METHOD

Using convenience sampling, chart covers of patients colonised or infected with VRE were swabbed from July to September 2010 (n=46). Samples were also collected from chart covers of non-VRE patients. Molecular typing of all matching VRE patient and chart isolates was performed using pulsed field gel electrophoresis (PFGE) by the public health laboratory (Microbiological Diagnostic Unit, University of Melbourne).

RESULTS

None of the patients who were VRE negative (n=14) had contaminated chart covers. VRE was recovered from two drug chart covers (patient A and B) from the 31 VRE positive patients sampled. One patient (patient C) was misidentified as a VRE patient for two weeks and was subject to contact precautions while being dialysed, yet three chart types belonging to this patient were found to be contaminated with VRE.

CONCLUSION

The findings of this study demonstrate that it is possible for patients' hospital chart covers to be contaminated with VRE even though there was no genetic similarity to the current patient strain. In this regard, the study reveals that patient charts may have an important role in spreading VRE.

Surveillance for vancomycin-resistant enterococci: type, rates, costs, and implications

OBJECTIVE

To evaluate 2 active surveillance strategies for detection of enteric vancomycin-resistant enterococci (VRE) in an intensive care unit (ICU).

DESIGN

Thirty-month prospective observational study.

SETTING

ICU at a university-affiliated referral center.

PATIENTS

All patients with an ICU stay of 24 hours or more were eligible for the study.

INTERVENTION

Clinical active surveillance (CAS), involving culture of a rectal swab specimen for detection of VRE, was performed on admission, weekly while the patient was in the ICU, and at discharge. Laboratory-based active surveillance (LAS), involving culture of a stool specimen for detection of VRE, was performed on stool samples submitted for Clostridium difficile toxin detection.

RESULTS

Enteric colonization with VRE was detected in 309 (17%) of 1,872 patients. The CAS method initially detected 280 (91%) of the 309 patients colonized with VRE, compared with 25 patients (8%) detected by LAS; colonization in 4 patients (1%) was initially detected by analysis of other clinical specimens. Most patients with colonization (76%) would have gone undetected by LAS alone, whereas use of the CAS method exclusively would have missed only 3 patients (1%) who were colonized. CAS cost Dollars 1,913 per month, or Dollars 57,395 for the 30-month study period. Cost savings of CAS from preventing cases of VRE colonization and bacteremia were estimated to range from Dollars 56,258 to Dollars 303,334 per month.

CONCLUSIONS

A patient-based CAS strategy for detection of enteric colonization with VRE was superior to LAS. In this high-risk setting, CAS appeared to be the most efficient and cost-effective surveillance method. The modest costs of CAS were offset by the averted costs associated with the prevention of VRE colonization and bacteremia.

New strategies to identify patients harbouring antibiotic-resistant bacteria at hospital admission

Nosocomial infections caused by antibiotic-resistant bacteria are associated with high morbidity and mortality worldwide. Most prevention strategies focus on cross-transmission, but the endemic state inside the hospital is also maintained through the influx of patients colonised or infected with antibiotic-resistant bacteria, balanced by the efflux of colonised patients following discharge. Epidemiological research has demonstrated that eradication can be achieved by preventing the influx of resistant bacteria. The presence of a central venous catheter and a history of methicillin-resistant Staphylococcus aureus (MRSA) infection or colonisation are associated significantly with methicillin-resistant staphylococcal bacteraemia at admission. Previous antibiotic therapy and transfer from long-term care facilities or nursing homes are associated with bacteraemia caused by methicillin-resistant coagulase-negative staphylococci, while skin ulcer and cellulites are independent risk-factors for MRSA bacteraemia. A scoring system using point values has been developed and validated to identify patients positive for vancomycin-resistant enterococci at admission. Six variables were identified: age > 60 years (2 points); hospitalisation in the previous year (3); use of two or more antibiotics during the previous 30 days (3); transfer from another hospital or long-term care facility (3); a requirement for chronic haemodialysis (2); and a previous history of MRSA infection (4). With a point score cut-off of > or = 10, the specificity of this prediction rule is 98%. Knowledge of variables identifying patients at high risk for being colonised or infected with antibiotic-resistant bacteria may assist clinicians in targeting preventive measures and streamlining the use of vancomycin. Current studies are analysing risk-factors for harbouring multiresistant Gram-negative bacteria at hospital admission.

Guidelines for the control of glycopeptide-resistant enterococci in hospitals

The increase since the mid 1980s in glycopeptide resistant enterococci (GRE) raised concerns about the limited options for antimicrobial therapy, the implications for ever-increasing numbers of immunocompromised hospitalised patients, and fuelled fears, now realised, for the transfer of glycopeptide resistance to more pathogenic bacteria, such as Staphylococcus aureus. These issues underlined the need for guidelines for the emergence and control of GRE in the hospital setting. This Hospital Infection Society (HIS) and Infection Control Nurses Association (ICNA) working party report reviews the literature relating to GRE prevention and control. It provides guidance on microbiological investigation, treatment and management, including antimicrobial prescribing and infection control measures. Evidence identified to support recommendations has been categorized. A risk assessment approach is recommended and areas for research and development identified.

Comparison of Mortality Associated with Vancomycin-Resistant and Vancomycin-Susceptible Enterococcal Bloodstream Infections: A Meta-analysis

BACKGROUND

Whether vancomycin resistance is independently associated with mortality among patients with enterococcal bloodstream infection (BSI) is controversial. To address this issue, we performed a systematic literature review with meta-analysis.

METHODS

Data sources were studies identified using the MEDLINE database (for articles from 1988 through March 2003), the Cochrane Library (for articles published up to March 2003), and bibliographies of identified articles. Inclusion criteria were that the study assessed mortality after enterococcal BSI, compared mortality after vancomycin-resistant enterococci (VRE) BSI with that after vancomycin-susceptible enterococci (VSE) BSI, and adjusted for severity of illness. Study exclusion criteria were as follows: no report of the adjusted measure of effect (adjusted odds ratio [OR], adjusted hazard ratio, or adjusted relative risk) of vancomycin resistance on mortality available and/or its adjusted 95% confidence interval (95% CI). Data in the tables, figures, or text were independently extracted by 2 of the authors. Individual weights were calculated using the 95% CI of the adjusted measures of effect performing both fixed-effect and random-effects models.

RESULTS

Nine studies were eligible (11 studies met the inclusion criteria, and 2 were excluded), with a total of 1614 enterococcal BSI episodes (683 VRE episodes and 931 VSE episodes). Patients with bacteremia caused by VRE were more likely to die than were those with VSE bacteremia (summary OR, 2.52; 95% CI, 1.9-3.4).

CONCLUSIONS

Vancomycin resistance is independently associated with increased mortality among patients with enterococcal bloodstream infection.

Preventing the Influx of Vancomycin‐Resistant Enterococci into Health Care Institutions, by Use of a Simple Validated Prediction Rule

BACKGROUND

The goal of this study was to develop a validated prediction rule for identification of patients harboring vancomycin-resistant enterococci (VRE) at hospital admission.

METHODS

A model for the prediction of patients harboring VRE at admission was created and validated by assigning weighted point values to independent risk factors associated with harboring VRE at admission, in 2 different cohorts of patients from 2 tertiary care hospitals in Boston, Massachusetts. Patients with VRE isolated from clinical culture samples collected within 48 h of hospital admission were compared with patients not harboring VRE. To assess the diagnostic accuracy of the prediction rule, the main outcome measures were patient demographic characteristics, comorbid illnesses, hospitalizations, and antibiotic exposure.

RESULTS

A total of 412 patients were enrolled. A risk index score was derived by using the following 6 independent risk factors associated with VRE recovery within 48 h of hospital admission: previous isolation of methicillin-resistant Staphylococcus aureus (MRSA), whether the patient was receiving long-term hemodialysis, transfer from a long-term care facility, antibiotic exposure, prior hospitalization, and age >60 years. On the basis of a point score >or=10, the sensitivity, specificity, and positive and negative predictive values of this prediction rule were 44%, 98%, 81%, and 90%, respectively.

CONCLUSIONS

This validated clinical prediction rule provides a novel strategy for the identification of patients at high risk of harboring VRE at hospital admission. Implementation of this rule may reduce the influx of VRE into health care institutions and the overall prevalence of VRE, by targeting VRE-screening measures and contact isolation precautions for these high-risk patients.

Debate—Guidelines for control of glycopeptide-resistant enterococci (GRE) have not yet worked

Glycopeptide-resistant enterococci (GRE) have become a focus of concern in many countries because options for antimicrobial therapy of GRE infection are limited. Several guidelines for the control and prevention of GRE colonization and infection have been developed for healthcare settings, and occasional journal articles now report "control" (usually relative reduction of incidence or prevalence rate rather than elimination) of GRE infections. Yet, rates of infection and colonization with GREcontinue to climb in many parts of the world, showing that true control has not been achieved. Programmes to control GRE will be effective only when they (1) are less expensive to implement; (2) are shown to be cost-effective despite the fact that they merely reduce prevalence levels rather than eradicating the problem; (3) do not require almost perfect implementation to be effective; (4) are shown to be sustainable; (5) are shown to work in acute-care settings other than selected academic centres; and (6) are shown to work in non-acute care settings. Until then, it is clear that guidelines for control of GRE have not worked. New guidelines that truly control GRE must be developed, and this must be done quickly.

Late-onset infection and the role of antibiotic prescribing policies

PURPOSE OF REVIEW

Late-onset infection is a significant cause of morbidity and mortality in low-birth-weight and premature infants. Empirical antibiotic treatment is used as infants can deteriorate rapidly without treatment. Current data on the epidemiology of late-onset infection, the types of antibiotics used, duration of antibiotic use, and antibiotic prescribing policies are reviewed.

RECENT FINDINGS

Epidemiological data on late-onset sepsis is dominated by information concerning developed countries; large prospective data collections have been set up in many such countries. Recent data indicate that late-onset sepsis occurs in one-fifth of very-low-birth-weight infants. There are increasing concerns regarding antibiotic resistance. Antibiotic regimens that do not include third-generation cephalosporins produce less resistance. Strategies of antibiotic rotation have not been documented as producing a marked effect on the development of resistant micro-organisms, but there is a lack of randomized trials. Recommendations for preventing the spread of vancomycin-resistant enterococci, produced by the Hospital Infection Control Practices Advisory Committee, have been shown to be effective in a number of situations. Recent reports have documented the success of multidisciplinary, systems-orientated approaches for reducing neonatal nosocomial infection.

SUMMARY

Antibiotic prescribing policies have an important role to play in the treatment of late-onset neonatal infection. There is enough evidence to state that narrow-spectrum antibiotics should be used wherever possible and that potent broad-spectrum antibiotics should be kept in reserve. Ongoing prospective surveillance of infection rates, micro-organisms, resistance and antibiotic use is essential.

Do physicians examine patients in contact isolation less frequently? A brief report

BACKGROUND

Patients who are hospitalized and infected with multidrug-resistant bacteria are usually placed in contact isolation, which requires hospital personnel to gown and glove before patient examination. Contact isolation with active culture surveillance appears beneficial in preventing the spread of drug-resistant infections; however, contact isolation may impede the ability to examine patients as a result of the additional effort required to gown and glove. We assessed whether patients who are hospitalized and placed under contact precautions are examined less often by second- and third-year medical residents (ie, senior medical residents), and attending physicians during morning rounds.

METHOD

We conducted a prospective cohort study on the inpatient medical services at 2 university-affiliated medical centers. We directly observed senior medical residents and attending physicians during morning rounds, and recorded the contact precaution status of the patient and whether they were examined by either physician.

RESULTS

Of a total of 139 patients, 31 (22%) were in contact isolation. Senior medical residents examined 26 of 31 patients (84%) in contact isolation versus 94 of 108 patients (87%) not in contact isolation (relative risk, 0.96; 95% confidence interval, 0.81-1.14; P =.58). In comparison, attending physicians examined 11 of 31 patients (35%) in contact isolation versus 79 of 108 patients (73%) not in contact isolation (relative risk, 0.49; 95% confidence interval, 0.30-0.79; P <.001).

DISCUSSION

Attending physicians are about half as likely to examine patients in contact isolation compared with patients not in contact isolation.