Differences in outcomes for patients with bacteremia due to vancomycin-resistant Enterococcus faecium or vancomycin-susceptible E. faecium

Impact of vancomycin resistance in Enterococcus faecium bloodstream infection on mortality: A retrospective analysis of nationwide surveillance data

OBJECTIVES

It is unclear whether the poor outcome of patients with severe vancomycin-resistant enterococci (VRE) infection is attributable to vancomycin resistance or to Enterococcus faecium (Efm), which predominates among VRE.

METHODS

Retrospective study of a prospectively identified cohort from nationwide surveillance. A cohort of consecutive, nonduplicate episodes of monomicrobial bloodstream infections (BSIs) caused by Efm in 2016 was selected. The primary outcome was all-cause, 30-day, in-hospital mortality. Inverse probability weighting was applied using the propensity score for vancomycin-resistant Efm (VREfm) BSI.

RESULTS

A total of 241 Efm BSI episodes were included, of which 59 (24.5%) were VREfm. Patients with VREfm BSI were younger but had similar comorbidities to those with vancomycin-sensitive Efm (VSEfm) BSI. Multivariable logistic regression revealed that younger age, previous piperacillin-tazobactam use, and steroid use were significant risk factors for VREfm BSI, but 30-day in-hospital mortality did not differ significantly between groups (35.6% and 23.6% for VREfm and VSEfm, respectively; odds ratio, 1.79; 95% confidence interval, 0.95-3.37; P = 0.101). However, Cox regression with inverse probability weighting revealed that vancomycin resistance was independently associated with an increased risk of mortality (adjusted hazard ratio, 2.18; 95% confidence interval, 1.03-4.62; P = 0.041).

CONCLUSION

In patients with Efm BSI, vancomycin resistance was independently associated with mortality.

Antibiotic choices among healthcare professionals for enterococcal bacteremia with patterns of resistance and risk factors of mortality, in settings of poor antibiotic stewardship program - a five-year retrospective cohort study

BACKGROUND

Enterococcal bacteremia has become prevalent in the recent decade, especially in hospitalized patients. Moreover, the rise in resistance patterns against antibiotic drugs regarding enterococci infection, such as cephalosporins, ampicillin and vancomycin, is prevailing. The major driving force behind this is the incongruous use of antibiotics with a minor contribution from environmental stressors which calls for vigilant and prudent administration of evidence-based antibiotics.

METHODS

A retrospective study was conducted from January 1 2017 until December 31 2021, at the tertiary care center, Dr Ziauddin Hospital in Karachi, Pakistan.

RESULTS

Our research revealed ampicillin resistance in 87 (63.5%), with an estimated 25 (18.8%) mortality. Male gender 19 (76%) and vancomycin resistance 13 (52%) were associated with increased mortality. Furthermore, appropriate antibiotic therapy reduced the risk of death compared with inappropriate and excessive use of antibiotics 10 (40%) vs. 15 (60%) vs. 20 (80%) respectively. Targeted therapy with amoxicillin/clavulanic acid was associated with lower mortality 1 (4%) and higher discharge rates 34 (32.1%). On Kaplan-Meier survival, targeted therapy with amoxicillin/clavulanic acid was associated with shorter hospital stays and prolonged survival. UTI was found as the most common source of enterococcal bacteremia 57 (41.6%), followed by respiratory 21 (15.3%) and intra-abdominal 13 (9.5%). In 26 (19%) patients, no identifiable source of infection was found.

CONCLUSION

Vancomycin resistance and male gender were found independent risk factors for mortality. The use of inappropriate antibiotics significantly increases mortality in these patients. The appropriate antibiotic therapy reduces the risk of death. Furthermore, overuse of antibiotics didn't reduce mortality; instead increased the financial burden and chances of developing multi-drug resistant strains of other organisms by increasing hospital stays of patients.

Prevalence of vancomycin-resistant enterococci in Asia-A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

The rise of vancomycin-resistant enterococci (VRE) has been a major health problem in most countries of the world including Asia, since its discovery. There is a paucity of data on VRE in many countries of Asia as well as limited pooled estimates. Therefore, we performed a systematic review and meta-analysis to estimate a pooled prevalence of VRE in Asia.

METHODS

A literature search in electronic databases like PubMed, Embase and Google Scholar and manual searching of references and grey literature, comprising the information on the prevalence of VRE with at least two species of enterococci, conducted in different countries of Asia from January 1, 2000, to September 20, 2020, was done. The random-effect model and 95% CIs was used to calculate the pooled prevalence. Subgroup, sensitivity and meta-regression analyses were performed to address heterogeneity while Egger's test for publication bias.

RESULTS AND DISCUSSIONS

We identified 39 studies, comprising a total of 11,875 enterococcal isolates. The result of the analysis showed that the pooled prevalence of VRE in Asia was 8.10% (95% CI; 7-9; I²  = 93.79%; p < 0.001). Resistance to vancomycin was greater among strains of E. faecium compared to the strains of E. faecalis (22.40% vs. 3.70%). Amongst various regions of Asia, the highest prevalence of VRE was found in the Western Asian region and the lowest in the South-east Asian region. Moreover, the rate of VRE was higher than most European countries and lower than USA.

WHAT IS NEW AND CONCLUSIONS

With an upsurge of VRE in Asia in recent years, efficient infection control programmes, robust surveillance systems and adherence to antibiotic stewardship are paramount to halt the further rise of VRE.

Vancomycin-resistant Enterococcus faecium COLONIZATION and Clostridium difficile infection in a HEMATOLOGIC patient

Vancomycin-resistant enterococci (VRE), especially Enterococcus faecium, have emerged as significant nosocomial pathogens and patients with impaired host defenses are at a particular risk of VRE infection. The most common occurrence is asymptomatic colonization of the gastrointestinal tract that can persist for a long time and serve as a reservoir for transmission of VRE to other patients. We present a case of a patient who was diagnosed with acute myelogenous leukemia and suffered from bone marrow aplasia following induction therapy. The patient received prolonged broad-spectrum antimicrobial therapy. During hospital stay, the patient developed Clostridium difficile infection (CDI) and was found to be colonized with a strain of Enterococcus faecium resistant to vancomycin during therapy for CDI. This case also highlights the role of risk factors that could contribute to development of resistance, particularly CDI. Early detection of VRE colonization or infection is a crucial component in hospital program designed to prevent transmission of nosocomial infections. Surveillance cultures of such patients should be mandatory.

Transplantation of a kidney from a donor with vancomycin-resistantEnterococci

The colonization of vancomycin-resistant Enterococci before and after solid organ transplantation is associated with an increased risk of its infection. The prevalence of these bacterial colonies in renal transplant recipients are as high as that in intensive care unit patients. However, it is unclear whether donors with vancomycin-resistant Enterococci colonization can be considered in renal transplantation. Herein, we report a case wherein a kidney was transplanted from a deceased donor with vancomycin-resistant Enterococci colonies in urine and rectal swab. After transplant, the recipient had no vancomycin-resistant Enterococci infection and maintained relatively good renal function.

Does vancomycin resistance increase mortality in Enterococcus faecium bacteraemia after orthotopic liver transplantation? A retrospective study

BACKGROUND

The relevance of vancomycin resistance in enterococcal blood stream infections (BSI) is still controversial. Aim of this study was to outline the effect of vancomycin resistance of Enterococcus faecium on the outcome of patients with BSI after orthotopic liver transplantation (OLT).

METHODS

The outcome of OLT recipients developing BSI with vancomycin-resistant (VRE) versus vancomycin-susceptible Enterococcus faecium (VSE) was compared based on data extraction from medical records. Multivariate regression analyses identified risk factors for mortality and unfavourable outcomes (defined as death or prolonged intensive care stay) after 30 and 90 days.

RESULTS

Mortality was similar between VRE- (n = 39) and VSE- (n = 138) group after 30 (p = 0.44) or 90 days (p = 0.39). Comparable results occurred regarding unfavourable outcomes. Mean SOFA_Non-GCS score during the 7-day-period before BSI onset was the independent predictor for mortality at both timepoints (HR 1.32; CI 1.14-1.53; and HR 1.18; CI 1.08-1.28). Timely appropriate antibiotic therapy, recent ICU stay and vancomycin resistance did not affect outcome after adjusting for confounders.

CONCLUSION

Vancomycin resistance did not influence outcome among patients with Enterococcus faecium bacteraemia after OLT. Only underlying severity of disease predicted poor outcome among this homogenous patient population.

TRIAL REGISTRATION

This study was registered at the German clinical trials register (DRKS-ID: DRKS00013285).

Increasing Frequencies of Antibiotic Resistant Non-typhoidal Salmonella Infections in Michigan and Risk Factors for Disease

Non-typhoidal Salmonella (NTS) are important enteric pathogens causing over 1 million foodborne illnesses in the U.S. annually. The widespread emergence of antibiotic resistance in NTS isolates has limited the availability of antibiotics that can be used for therapy. Since Michigan is not part of the FoodNet surveillance system, few studies have quantified antibiotic resistance frequencies and identified risk factors for NTS infections in the state. We obtained 198 clinical NTS isolates via active surveillance at four Michigan hospitals from 2011 to 2014 for classification of serovars and susceptibility to 24 antibiotics using broth microdilution. The 198 isolates belonged to 35 different serovars with Enteritidis (36.9%) predominating followed by Typhimurium (19.5%) and Newport (9.7%), though the proportion of each varied by year, residence, and season. The number of Enteritidis and Typhimurium cases was higher in the summer, while Enteritidis cases were significantly more common among urban vs. rural residents. A total of 30 (15.2%) NTS isolates were resistant to ≥1 antibiotic and 15 (7.5%) were resistant to ≥3 antimicrobial classes; a significantly greater proportion of Typhimurium isolates were resistant compared to Enteritidis isolates and an increasing trend in the frequency of tetracycline resistance and multidrug resistance was observed over the 4-year period. Resistant infections were associated with longer hospital stays as the mean stay was 5.9 days for patients with resistant isolates relative to 4.0 days for patients infected with susceptible isolates. Multinomial logistic regression indicated that infection with serovars other than Enteritidis [Odds ratio (OR): 3.8, 95% confidence interval (CI): 1.23-11.82] as well as infection during the fall (OR: 3.0; 95% CI: 1.22-7.60) were independently associated with resistance. Together, these findings demonstrate the importance of surveillance, monitoring resistance frequencies, and identifying risk factors that can aid in the development of new prevention strategies.

Vancomycin-resistant enterococci (VRE) screening and isolation in the general medicine ward: a cost-effectiveness analysis

Background

Vancomycin-resistant enterococci (VRE) are a serious antimicrobial resistant threat in the healthcare setting. We assessed the cost-effectiveness of VRE screening and isolation for patients at high-risk for colonisation on a general medicine ward compared to no VRE screening and isolation from the healthcare payer perspective.

Methods

We developed a microsimulation model using local data and VRE literature, to simulate a 20-bed general medicine ward at a tertiary-care hospital with up to 1000 admissions, approximating 1 year. Primary outcomes were accrued over the patient's lifetime, discounted at 1.5%, and included expected health outcomes (VRE colonisations, VRE infections, VRE-related bacteremia, and deaths subsequent to VRE infection), quality-adjusted life years (QALYs), healthcare costs, and incremental cost-effectiveness ratio (ICER). Probabilistic sensitivity analysis (PSA) and scenario analyses were conducted to assess parameter uncertainty.

Results

In our base-case analysis, VRE screening and isolation prevented six healthcare-associated VRE colonisations per 1000 admissions (6/1000), 0.6/1000 VRE-related infections, 0.2/1000 VRE-related bacteremia, and 0.1/1000 deaths subsequent to VRE infection. VRE screening and isolation accrued 0.0142 incremental QALYs at an incremental cost of $112, affording an ICER of $7850 per QALY. VRE screening and isolation practice was more likely to be cost-effective (> 50%) at a cost-effectiveness threshold of $50,000/QALY. Stochasticity (randomness) had a significant impact on the cost-effectiveness.

Conclusion

VRE screening and isolation can be cost-effective in majority of model simulations at commonly used cost-effectiveness thresholds, and is likely economically attractive in general medicine settings. Our findings strengthen the understanding of VRE prevention strategies and are of importance to hospital program planners and infection prevention and control.

The rise in vancomycin-resistant Enterococcus faecium in Germany: data from the German Antimicrobial Resistance Surveillance (ARS)

Background

Due to limited therapeutic options, vancomycin-resistant Enterococcus faecium (VREF) is of great clinical significance. Recently, rising proportions of vancomycin resistance in enterococcal infections have been reported worldwide. This study aims to describe current epidemiological trends of VREF in German hospitals and to identify factors that are associated with an increased likelihood of vancomycin resistance in clinical E. faecium isolates.

Methods

2012 to 2017 data from routine vancomycin susceptibility testing of 35,906 clinical E. faecium isolates from 148 hospitals were analysed using data from the German Antimicrobial Resistance Surveillance System. Descriptive statistical analyses and uni- and multivariable regression analyses were performed to investigate the impact of variables, such as year of sampling, age and region, on vancomycin resistance in clinical E. faecium isolates.

Results

From 2014 onwards the proportions of clinical E. faecium isolates exhibiting resistance to vancomycin increased from 11.2% (95% confidence interval [CI] 9.4-13.3%) to 26.1% (95% CI 23.1-29.4%) in 2017. The rise of VREF proportions is primarily observed in the southern regions of Germany, whereas northern regions do not show a major increase. In the Southwest and Southeast, VREF proportions increased from 10.8% (95% CI 6.9-16.5%) and 3.8% (95% CI 3.0-11.5%) in 2014 to 36.7% (95% CI 32.9-40.8%) and 36.8% (95% CI 29.2-44.7%) in 2017, respectively. VREF proportions were considerably higher in isolates from patients aged 40-59 years compared to younger patients. Further regression analyses show that in relation to secondary care hospitals, E. faecium samples collected in specialist care hospitals and prevention and rehabilitation care centres are more likely to be vancomycin-resistant (odds ratios: 2.4 [95% CI 1.2-4.6] and 2.4 [95% CI 1.9-3.0], respectively). No differences in VREF proportions were found between female and male patients as well as between different clinical specimens.

Conclusion

The proportion of VREF is increasing in German hospitals, particularly in southern regions in Germany. Increased efforts in infection control and antibiotic stewardship activities accounting for local resistance patterns are necessary to combat the spread of VREF in Germany.

The direct and indirect effects of vancomycin-resistant enterococci colonization in liver transplant candidates and recipients

Introduction: Vancomycin-resistant enterococci (VRE) colonization and subsequent infection results in increased morbidity, mortality and use of health-care resources. The burden of VRE colonization in liver transplant candidates and recipients is significant. VRE colonization is a marker of gut dysbiosis and its impact on the microbiota-liver axis, may negatively affect graft function and result in negative outcomes pre- and post-transplantation. Areas covered: In this article we describe the epidemiology of VRE colonization, risk factors for VRE infection, health-care costs associated with VRE, with a focus on the impact of VRE colonization on liver transplant recipients' fecal microbiota, the therapeutic strategies for VRE decolonization and proposed pathophysiologic mechanisms of VRE colonization in liver transplant recipients. Expert opinion: VRE colonization results in a significant loss of bacterial microbiome diversity. This may have metabolic consequences, with low production of short-chain fatty acids which may, in turn, result in immune dysregulation. As antibiotics have failed to decolonize the gut, alternative strategies such as fecal microbiota transplantation (FMT), stimulation of intestinal antimicrobial peptides and phage therapy warrants future studies.

From days to hours: Can MALDI-TOF MS system replace both conventional and molecular typing methods with new cut off level for Vancomycin Resistant Enterococcus faecium

Vancomycin-Resistant E. faecium (VRE) strains from clinical specimens were identified by conventional methods before. Following the phenotype-based identification, all strains were also identified using both BD Phoenix and VITEK MS bioMérieux System. Strains were typed with the Bruker MALDI-TOF MS system, pulsed field gel electrophoresis (PFGE) and 16S rRNA gene sequencing analysis and then the sensitivity compared for each. A cut off value of 850 assigned with Bruker MALDI-TOF MS system was found to give equal sensitivity to that of PFGE. Results obtained were compared with those of molecular typing. The main advantage of MALDI-TOF MS technology over the others was the much shorter analysis time which lasted only a few hours rather than days or a whole week. Also, the Bruker MALDI-TOF MS system was used for typing and compared with the gold standard method and this study is first to report the determined cut off level for typing of VRE strains.

Management of bacterial and fungal infections in end stage liver disease and liver transplantation: Current options and future directions

Patients with liver cirrhosis are susceptible to infections due to various mechanisms, including abnormalities of humoral and cell-mediated immunity and occurrence of bacterial translocation from the intestine. Bacterial infections are common and represent a reason for progression to liver failure and increased mortality. Fungal infections, mainly caused by Candida spp., are often associated to delayed diagnosis and high mortality rates. High level of suspicion along with prompt diagnosis and treatment of infections are warranted. Bacterial and fungal infections negatively affect the outcomes of liver transplant candidates and recipients, causing disease progression among patients on the waiting list and increasing mortality, especially in the early post-transplant period. Abdominal, biliary tract, and bloodstream infections caused by Gram-negative bacteria [e.g., Enterobacteriaceae and Pseudomonas aeruginosa (P. aeruginosa)] and Staphylococcus spp. are commonly encountered in liver transplant recipients. Due to frequent exposure to broad-spectrum antibiotics, invasive procedures, and prolonged hospitalizations, these patients are especially at risk of developing infections caused by multidrug resistant bacteria. The increase in antimicrobial resistance hampers the choice of an adequate empiric therapy and warrants the knowledge of the local microbial epidemiology and the implementation of infection control measures. The main characteristics and the management of bacterial and fungal infections in patients with liver cirrhosis and liver transplant recipients are presented.

Genome-Based Analysis of Enterococcus faecium Bacteremia Associated with Recurrent and Mixed-Strain Infection

Vancomycin-resistant Enterococcus faecium (VREfm) bloodstream infections are associated with high recurrence rates. This study used genome sequencing to accurately distinguish the frequency of relapse and reinfection in patients with recurrent E. faecium bacteremia and to investigate strain relatedness in patients with apparent VREfm and vancomycin-susceptible E. faecium (VSEfm) mixed infection. A retrospective study was performed at the Cambridge University Hospitals NHS Foundation Trust (CUH) between November 2006 and December 2012. We analyzed the genomes of 44 E. faecium isolates from 21 patients (26 VREfm isolates from 12 patients with recurrent bacteremia and 18 isolates from 9 patients with putative VREfm/VSEfm mixed infection). Phenotypic antibiotic susceptibility was determined using a Vitek2 instrument. Genomes were compared with those of a further 263 E. faecium isolates associated with bacteremia in patients at CUH over the same time period. Pairwise comparison of core genomes indicated that 10 (71%) episodes of recurrent VREfm bacteremia were due to reinfection with a new strain, with reinfection being more likely with increasing time between the two positive cultures. The majority (78%) of patients with a mixed VREfm and VSEfm infection had unrelated strains. More than half (59%) of study isolates were closely related to another isolate associated with bacteremia from CUH. This included 60% of isolates associated with reinfection, indicating acquisition in the hospital. This study provides the first high-resolution insights into recurrence and mixed infection by E. faecium and demonstrates that reinfection with a new strain, often acquired from the hospital, is a driver of recurrence.

Economic burden of nosocomial infections caused by vancomycin-resistant enterococci

Background

Nosocomial infections due to vancomycin-resistant enterococci (VRE) have become a major problem during the last years. The purpose of this study was to investigate the economic burden of nosocomial VRE infections in a European university hospital.

Methods

A retrospective matched case-control study was performed including patients who acquired nosocomial infection with either VRE or vancomycin-susceptible enterococci (VSE) within a time period of 3 years. 42 cases with VRE infections and 42 controls with VSE infections were matched for age, gender, admission and discharge within the same year, time at risk for infection, Charlson comorbidity index (±1), stay on intensive care units and non-intensive care units as well as for the type of infection, using criteria of the Centers for Disease Control and Prevention.

Results

The median overall costs per case were significantly higher than for controls (EUR 57,675 vs. EUR 38,344; p = 0.030). Costs were similar between cases and controls before onset of infection (EUR 17,893 vs. EUR 16,600; p = 0.386), but higher after onset of infection (EUR 37,971 vs. EUR 23,025; p = 0.049). The median attributable costs per case for vancomycin-resistance were EUR 13,157 (p = 0.036). The most significant differences in costs between cases and controls turned out to be for pharmaceuticals (EUR 6030 vs. EUR 2801; p = 0.008) followed by nursing staff (EUR 8956 vs. EUR 4621; p = 0.032), medical products (EUR 3312 vs. EUR 1838; p = 0.020), and for assistant medical technicians (EUR 3766 vs. EUR 2474; p = 0.023). Furthermore, multivariate analysis revealed that costs were driven independently by vancomycin-resistance (1.4 fold; p = 0.034).

Conclusions

This analysis suggested that nosocomial VRE infections significantly increases hospital costs compared with VSE infections. Therefore, hospital personal should implement control measures to prevent VRE transmission.

Incidence, clinical characteristics, and outcomes of nosocomial Enterococcus spp. bloodstream infections in a tertiary-care hospital in Beijing, China: a four-year retrospective study

Background

Enterococcus spp. are the common cause of nosocomial bloodstream infections (BSIs) with high morbidity and mortality. The purpose of this study was to characterize the incidence, clinical and microbiological features, and mortality of nosocomial enterococcal BSIs at a large Chinese tertiary-care hospital in Beijing, China.

Methods

A retrospective cohort study on adult patients with nosocomial BSIs due to Enterococcus spp. was performed between January 1, 2012, and December 31, 2015 at the Chinese People’s Liberation Army General Hospital. Patients’ data were gathered by reviewing electronic medical records.

Results

A total of 233 episodes of BSI due to Enterococcus spp. occurred among 224 patients during these 4 years. The overall incidence was 3.9 episodes per 10,000 admissions. Enterococcus faecium (E. faecium) was the major pathogen (74%, 95% CI 68–80%), followed by Enterococcus faecalis (E. faecalis) (20%, 95% CI 15–25%). E. faecium showed higher antimicrobial resistance than E. faecalis. The 30-day mortality of nosocomial enterococcal BSI was 24% (95% CI 18–29%). Predictors for mortality included the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, Charlson comorbidity index (CCI), impaired renal function, prior use of immunosuppressive agents, and appropriate empirical antimicrobial treatment.

Conclusions

This study emphasizes that Enterococcus spp. were major pathogens for nosocomial BSIs and associated with high mortality. Appropriate empirical antimicrobial treatment can improve outcomes. Vancomycin is the best choice for patients with E. faecium BSIs. Penicillins, aminoglycosides, fluoroquinolones, and vancomycin can be considered for patients with E. faecalis BSIs.

Vancomycin gene selection in the microbiome of urban Rattus norvegicus from hospital environment

Background and objectives: Widespread use of antibiotics has resulted in selection pressure on genes that make bacteria non-responsive to antibiotics. These antibiotic-resistant bacteria are currently a major threat to global health. There are various possibilities for the transfer of antibiotic resistance genes. It has been argued that animal vectors such as Rattus norvegicus (R. norvegicus) living in hospital sewage systems are ideal for carrying pathogens responsible for fatal diseases in humans. Methodology: Using a metagenomic sequencing approach, we investigated faecal samples of R. norvegicus from three major cities for the presence of antibiotic resistance genes. Results: We show that despite the shared resistome within samples from the same geographic locations, samples from hospital area carry significantly abundant vancomycin resistance genes. Conclusions and implications: The observed pattern is consistent with a selection for vancomycin genes in the R. norvegicus microbiome, potentially driven by the outflow of antibiotics and antibiotic-resistant bacteria into the wastewater systems. Carriage of vancomycin resistance may suggest that R. norvegicus is acting as a reservoir for possible transmission to the human population.

Descriptive Epidemiology and Case-Control Study of Patients Colonized With Vancomycin-Resistant Enterococcus and Methicillin-ResistantStaphylococcus aureus

Background.

Patients colonized or infected with vancomycin-resistant enterococcus and methicillin-resistantStaphylococcus aureusmay be at risk of acquiring vancomycin-resistantS. aureusif the vanA gene is transferred from vancomycin-resistant enterococcus to methicillin-resistantS. aureus..

Objective.

Our goal was to identify risk factors for cocolonization or coinfection (CC/CI) with vancomycin-resistant enterococcus and methicillin-resistantS. aureus.

Design.

We conducted a descriptive, epidemiologic study of all patients with CC/CI identified from January 1998 to May 2003 and a nested case-control study of a cohort of patients hospitalized in the burn and wound unit.

Setting.

We conducted our study in a 813-bed tertiary care university teaching hospital.

Population.

The study population consisted of patients found to have CC/CI during the study period.

Methods.

Descriptive epidemiologic data were collected from hospital records of all patients identified as having CC/CI. A subset of patients hospitalized in the burn and wound unit were included in a case-control study.

Results.

CC/CI was detected in 71% of the patients during a single hospital stay. The burn and wound unit, which does active surveillance for both organisms, and the general medicine unit, which does not do active surveillance for either organism, cared for more than one-half of these patients. Among patients being cared for in the burn and wound unit, having exposure to 2 or more invasive devices (central venous catheters, indwelling urinary catheters, and enteral feeding tubes) and renal insufficiency were independent risk factors for CC/CI.

Conclusions.

Patients with CC/CI are the population at greatest risk for vancomycin-resistantS. aureuscolonization or infection. The number of invasive devices to which patients are exposed and, thus, possibly the patients' underlying severity of illness, as well as renal insufficiency, appear to be risk factors for CC/CI.

Infection Prevention and Control Issues After Solid Organ Transplantation

Infections are an important cause of morbidity and mortality in solid organ transplant recipients. Consequently, infection prevention is an essential component of any organ transplant program. Given their frequent and often prolonged contact with the healthcare system, solid organ transplant recipients are at high risk for healthcare-associated infections, including those caused by antibiotic-resistant organisms. In this chapter we review several different healthcare-associated infections of importance to transplant recipients, including those caused by bacterial, viral, and fungal organisms. We also describe infection prevention and control strategies applicable to this patient population. These practices focus on clinical interventions and environmental controls designed to prevent the spread of potentially pathogenic organisms in the healthcare setting. We also describe post-exposure interventions applicable to solid organ transplant recipients exposed to potential pathogens in order to reduce their risk of subsequent infection.

Outcomes for and Risk Factors Associated With Vancomycin-ResistantEnterococcus faecalisand Vancomycin-ResistantEnterococcus faeciumBacteremia in Cancer Patients

Objective.

Vancomycin-resistant enterococci (VRE) are a major cause of nosocomial infection. We sought to compare vancomycin-resistant (VR)Enterococcus faecalisbacteremia and VREnterococcus faeciumbacteremia in cancer patients with respect to risk factors, clinical presentation, microbiological characteristics, antimicrobial therapy, and outcomes.

Methods.

We identified 210 cancer patients with VRE bacteremia who had been treated between January 1996 and December 2004; 16 of these 210 had VRE. faecalisbacteremia and were matched with 32 patients with VRE. faeciumbacteremia and 32 control patients. A retrospective review of medical records was conducted.

Results.

Logistic regression analysis showed that, compared with VRE. faecalisbacteremia, VRE. faeciumbacteremia was associated with a worse clinical response to therapy (odds ratio [OR], 0.3 [95% confidence interval (CI), 0.07-0.98];P= .046) and a higher overall mortality rate (OR, 8.3 [95% CI, 1.9-35.3];P= .004), but the VRE-related mortality rate did not show a statistically significant difference (OR, 6.8 [95% CI, 0.7-61.8];P= .09). Compared with control patients, patients with VRE. faecalisbacteremia were more likely to have received an aminoglycoside in the 30 days before the onset of bacteremia (OR, 5.8 [95% CI, 1.2-27.6];P= .03), whereas patients with VRE. faeciumbacteremia were more likely to have received a carbapenem in the 30 days before the onset of bacteremia (OR, 11.7 [95% CI, 3.6-38.6];P<.001). In a multivariate model that compared patients with VRE. faeciumbacteremia and control patients, predictors of mortality included acute renal failure on presentation (OR, 15.1 [95% CI, 2.3-99.2];P= .004) and VRE. faeciumbacteremia (OR, 11 [95% CI, 2.7-45.1];P<.001). No difference in outcomes was found between patients with VRE. faecalisbacteremia and control patients.

Conclusions.

VRE. faeciumbacteremia in cancer patients was associated with a poorer outcome than was VRE. faecalisbacteremia. Recent receipt of carbapenem therapy was an independent risk factor for VRE. faeciumbacteremia, and recent receipt of aminoglycoside therapy was independent risk factor forE. faecalisbacteremia.

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.

Risk of Vancomycin-ResistantEnterococcus(VRE) Bloodstream Infection Among Patients Colonized With VRE

Background.

Colonization with vancomycin-resistantEnterococcus(VRE) is a risk factor for subsequent VRE bloodstream infection (BSI); however, risk factors for BSI among colonized patients have not been adequately described. We sought to determine the proportion of VRE-colonized patients who subsequently develop VRE BSI and to identify risk factors for VRE BSI among these patients.

Methods.

Records of 768 patients colonized with VRE from January 2002 through June 2005 were reviewed. The proportion of patients who developed VRE BSI was calculated, and the characteristics of these patients were compared, in a 2 : 1 ratio, with those of patients who did not develop VRE BSI. To identify risk factors for VRE BSI and for death, we used univariate logistic regression analysis and then multivariate logistic regression analysis. Using pulsed-field gel electrophoresis (PFGE), we compared the isolate recovered when the patient was colonized and the isolate recovered when the patient developed VRE BSI.

Results.

Of the 768 patients colonized with VRE, 31 (4.0%) developed VRE BSI. Multivariate analysis identified the following idependent risk factors for developing VRE BSI: infection of an additional body site other than blood (adjusted odds ratio [aOR], 3.9;P= .04), admission to the hospital from a long-term care facility (aOR, 12.6;P= .04), and receipt of vancomycin (aOR, 10.6;P< .001). The independent risk factors for death among patients colonized with VRE were immunosuppression (aOR, 12.9;P= .001 ) and VRE BSI (aOR, 9.1;P= .002). Of the 31 patients who developed VRE BSI, 23 (74%) had a pair of isolates representing VRE colonization and VRE BSI. For 19 (83%) of these 23 patients, the isolate representing BSI was genetically related to the isolate representing VRE colonization: 12 pairs of isolates (52%) had identical banding patterns, 5 had closely related patterns, and 2 had possibly related patterns.

Conclusion.

Of the 768 patients colonized with VRE, 31 (4.0%) usually developed VRE BSI due to a related strain. Independent risk factors for BSI among colonized patients were admission from a long-term care facility, infection of an additional body site, and exposure to vancomycin. Independent risk factors for death were immunosuppression and VRE BSI.

Disposition of linezolid or daptomycin in Enterococcal bloodstream infections according to vancomycin resistant Enterococcus colonization

Vancomycin resistant Enterococcus (VRE) colonized patients are likely to receive VRE targeted Gram-positive antibiotics and may not be de-escalated appropriately once final cultures are available. A retrospective cohort study was conducted in VRE-colonized and non-VRE colonized patients with Enterococcal bloodstream infections. Of 101 patients (n = 50 VRE-colonized; n = 51 non-colonized), empiric therapy with linezolid or daptomycin was started more often in VRE-colonized than non-colonized patients (n = 8, 15.5% vs n = 27, 54%, p < 0.01). There was no difference in de-escalation once VRE infection was ruled out (non-colonized, n = 2, 66.7% vs VRE-colonized, n = 2, 50%, p = 0.09). This study encourages continued stewardship vigilance to decrease inappropriate antibiotic use.

Impact of vancomycin resistance on mortality in neutropenic patients with enterococcal bloodstream infection: a retrospective study

BACKGROUND

Vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) is generally associated with the delayed administration of adequate antibiotics. The identification of risk factors and outcomes of VRE BSI is necessary for establishing strategies for managing neutropenic fever in patients with hematological malignancies.

METHODS

We retrospectively analysed consecutive cases of enterococcal BSI in patients with neutropenia after chemotherapy or stem cell transplantation between July 2009 and December 2011 at a single center.

RESULTS

During the 30-month period, among 1,587 neutropenic patients, the incidence rate of enterococcal BSI was 1.76 cases per 1,000 person-days. Of the 91 enterococcal BSIs, there were 24 cases of VRE. VRE BSI was associated with E. faecium infection (P < .001), prolonged hospitalization (P = .025) and delayed administration (≥ 48 hours after the febrile episode) of adequate antibiotics (P = .002). The attributable mortality was 17% and 9% for VRE and vancomycin-susceptible Enterococcus (VSE), respectively (P = .447). The 30-day crude mortality was 27% and 23% for VRE and VSE, respectively (OR 1.38, 95% CI 0.53-3.59; P = .059). Only SAPS-II was an independent predictive factor for death (adjusted OR 1.12, 95% CI 1.08-1.17; P < .001).

CONCLUSIONS

In conclusion, vancomycin resistance showed some trend towards increasing 30-day mortality, but is not statistically significant despite the delayed use of adequate antibiotics (≥48 hours). Only underlying severity of medical condition predicts poor outcome in a relatively homogeneous group of neutropenic patients.

Vancomycin-resistant enterococci colonization-infection model: parameter impacts and outbreak risks

Vancomycin-resistant enterococci (VRE) infections have been linked to increased mortality and costs. A new model of a VRE-infested intensive care unit (ICU) is introduced. It incorporates critical features including the difference between colonization and infection, the role of special preventive care treatment cycles, fitness cost, and antibiotic use. Five patient stages are considered: susceptible, colonized with and without special preventive care, and infected with and without treatment. Parameter ranges are determined representing different ICUs and incorporated to numerically simulate the model. Basic reproductive number of the infection is derived and the impacts of the parameters are analysed. Strategies to minimize VRE infections and outbreak risk are explored with a focus on efficient and simultaneous control of critical parameters. In particular, threshold values of the level of special preventive care and ICU compliance rate are given to achieve desired goals under various constraints.

Risk Factors and Outcomes for Vancomycin-Resistant Enterococcus Bloodstream Infection in Children

Background and objective. Enterococcal bloodstream infections (BSIs) cause morbidity and mortality in children. This study aims to describe the epidemiological characteristics of enterococcal BSI, to determine the risk factors for vancomycin-resistant Enterococcus (VRE) BSI, and to compare outcomes of VRE BSI and vancomycin-susceptible Enterococcus (VSE) BSI in this population. Methods. A retrospective cohort study at a 418-bed tertiary care children's hospital in Philadelphia, Pennsylvania, examined the epidemiological characteristics of children hospitalized with enterococcal BSI during the period from 2001 through 2006. A nested case-control study compared patients with VRE BSI with control patients with VSE BSI. Analysis included regression modeling to identify independent risk factors for VRE BSI. Results. We identified 339 patients with enterococcal BSI during the study period, including 39 patients with VRE infection. Fifty-three patients (16%) died before hospital discharge. Risk factors for VRE included long-term receipt of mechanical ventilation (adjusted odds ratio [OR], 5.40 [95% confidence interval {CI}, 1.28-6.48]), receipt of immunosuppressive medications during the preceding 30 days (adjusted OR, 2.88 [95% CI, 1.40-20.78]), use of vancomycin during the 2 weeks before onset of bacteremia (adjusted OR per day of vancomycin use, 1.25 [95% CI, 1.14-1.38]), and older age (adjusted OR, 1.08 [95% CI, 1.03-1.14]). VRE BSI was not associated with an increased length of stay after onset of bacteremia (0.77 days [95% CI, 0.55-1.07 days]). Mortality was higher for VRE BSI, but the difference was not statistically significant (adjusted OR, 1.94 [95% CI, 0.78-4.8]). Conclusion. Most enterococcal BSI in children was caused by VSE. Risk factors for VRE BSI included receipt of vancomycin, long-term receipt of mechanical ventilation, immunosuppression, and older age. Differences in length of stay and mortality were not detected.

Prospective, multicenter evaluation of the BD GeneOhm VanR assay for direct, rapid detection of vancomycin-resistant Enterococcus species in perianal and rectal specimens

The BD GeneOhm VanR assay (BD Diagnostics, San Diego, CA), a qualitative test for the rapid detection of vancomycin-resistant enterococci (VRE) from rectal and/or perianal swabs, combines integrated nucleic acid extraction and automated polymerase chain reaction for the detection of vanA and/or vanB gene sequences. We studied 1,027 perianal and rectal swab specimens from 3 geographically distinct US sites (prevalence rates, 13.1%-25.8%). Direct swab specimens were tested by the assay and compared with direct culture. The sensitivity, specificity, and positive and negative predictive values of the assay were 93.2%, 81.9%, 54.4%, and 98.1%, respectively. The specificity was limited largely due to false-positives in the vanB portion of the assay. Specificity with perianal swabs was significantly greater than with rectal swabs, 87.1% vs 74.7%, respectively (P < .0001). When used only to detect resistance conferred by vanA, the assay was 88.3% (158/179) sensitive and 95.8% (802/837) specific, with positive and negative predictive values of 81.9% and 97.4%, respectively. The assay is a simple, rapid, and acceptable method for screening for VRE in a variety of populations in which vanA is the predominant genotype. Samples positive for the vanB genotype should be confirmed by culture owing to the apparent high number of false-positive results.

Attributable costs of enterococcal bloodstream infections in a nonsurgical hospital cohort

BACKGROUND

Vancomycin-resistant Enterococcus (VRE) bloodstream infections (BSIs) are associated with increased morbidity and mortality.

OBJECTIVE

To determine the hospital costs and length of stay attributable to VRE BSI and vancomycin-sensitive Enterococcus (VSE) BSI and the independent effect of vancomycin resistance on hospital costs.

METHODS

A retrospective cohort study was conducted of 21,154 nonsurgical patients admitted to an academic medical center during the period from 2002 through 2003. Using administrative data, attributable hospital costs (adjusted for inflation to 2007 US dollars) and length of stay were estimated with multivariate generalized least-squares (GLS) models and propensity score-matched pairs.

RESULTS

The cohort included 94 patients with VRE BSI and 182 patients with VSE BSI. After adjustment for demographics, comorbidities, procedures, nonenterococcal BSI, and early mortality, the costs attributable to VRE BSI were $4,479 (95% confidence interval [CI], $3,500-$5,732) in the standard GLS model and $4,036 (95% CI, $3,170-$5,140) in the propensity score-weighted GLS model, and the costs attributable to VSE BSI were $2,250 (95% CI, $1,758-$2,880) in the standard GLS model and $2,023 (95% CI, $1,588-$2,575) in the propensity score-weighted GLS model. The median values of the difference in costs between matched pairs were $9,949 (95% CI, $1,579-$24,693) for VRE BSI and $5,282 (95% CI, $2,042-$8,043) for VSE BSI. The costs attributable to vancomycin resistance were $1,713 (95% CI, $1,338-$2,192) in the standard GLS model and $1,546 (95% CI, $1,214-$1,968) in the propensity score-weighted GLS model. Depending on the statistical method used, attributable length of stay estimates ranged from 2.2 to 3.5 days for patients with VRE BSI and from 1.1 to 2.2 days for patients with VSE BSI.

CONCLUSIONS

VRE BSI and VSE BSI were independently associated with increased hospital costs and increased length of stay. Vancomycin resistance was associated with increased costs.

Therapeutic options for infections due to vancomycin-resistant enterococci

BACKGROUND

Vancomycin-resistant enterococci (VRE) are an important cause of nosocomial infection occurring in critical care or immunocompromised patients.

OBJECTIVES

To provide updated information about therapeutic options for VRE infection.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched to identify in vitro susceptibility data of VRE isolates, randomized and non-randomized controlled trials, case series, and cohort studies of VRE therapy published before 31 July 2008.

RESULTS/CONCLUSION

The updated in vitro susceptibility data for VRE show high resistance to ampicillin and aminoglycosides. Quinupristin-dalfopristin is limited by its lack of activity against vancomycin-resistant Enterococcus faealis and its musculoskeletal side effects. Emerging linezolid resistance has been reported to cause hospital spread and may be related to prolonged linezolid use. Quinupristin-dalfopristin resistance is usually linked to agricultural use of streptogramin. Nitrofurantoin and fosfomycin are alternatives in uncomplicated VRE urinary tract infection. Daptomycin and tigecycline have shown excellent potential for treating VRE infection.

Global resistance trends and the potential impact on empirical therapy

Globally, antibiotic resistance continues to be an increasing problem. The emergence of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and extended spectrum beta-lactamase-producing Enterobacteriaceae has seriously reduced the number of empirical agents suitable for selected indications. Increasing Gram-negative resistance has also negatively impacted the physician's alternatives when choosing adequate initial therapy; increased reliance on the carbapenem class as empirical agents has led to the emergence of multidrug resistance in non-enteric Gram-negative bacilli. There is a critical need for new, broad-spectrum alternatives to the currently available broad-spectrum agents.

Vancomycin resistance: are there better glycopeptides coming?

The appearance and dissemination of vancomycin resistance among clinically important Gram-positive bacteria was an important watershed in antimicrobial resistance trends that drastically narrows therapeutic options, particularly among the enterococci. Clinical resistance despite apparent susceptibility has also become an increasingly recognized issue with vancomycin treatment of methicillin-resistant Staphylococcus aureus pneumonia and endocarditis, which may be, in part, due to vancomycin-heteroresistant strains. The newly developed glycopeptides telavancin, dalbavancin and oritavancin have superior in vitro activity, enhanced bactericidality and unique pharmacokinetic properties compared with vancomycin and teicoplanin. Current clinical trial data show noninferiority to vancomycin or standard-of-care antistaphylococcal therapy for complicated skin-skin structure infections, and acceptable safety profiles. Although promising, whether or not these new compounds are clinically efficacious for the true therapeutic deficits created by in vitro and clinical vancomycin resistance is yet to be determined.

Clinical and economic burden of antimicrobial resistance

Knowledge of the clinical and economic impact of antimicrobial resistance is useful to influence programs and behavior in healthcare facilities, to guide policy makers and funding agencies, to define the prognosis of individual patients and to stimulate interest in developing new antimicrobial agents and therapies. There are a variety of important issues that must be considered when designing or interpreting studies into the clinical and economic outcomes associated with antimicrobial resistance. One of the most misunderstood issues is how to measure cost appropriately. Although imperfect, existing data show that there is an association between antimicrobial resistance in Staphylococcus aureus, enterococci and Gram-negative bacilli and increases in mortality, morbidity, length of hospitalization and cost of healthcare. Patients with infections due to antimicrobial-resistant organisms have higher costs (US $6,000-30,000) than do patients with infections due to antimicrobial-susceptible organisms; the difference in cost is even greater when patients infected with antimicrobial-resistant organisms are compared with patients without infection. Given limited budgets, knowledge of the clinical and economic impact of antibiotic-resistant bacterial infections, coupled with the benefits of specific interventions targeted to reduce these infections, will allow for optimal control and improved patient safety. In this review, the authors discuss a variety of important issues that must be considered when designing or interpreting studies of the clinical and economic outcomes associated with antimicrobial resistance. Representative literature is reviewed regarding the associations between antimicrobial resistance in specific pathogens and adverse outcomes, including increased mortality, length of hospital stay and cost.

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

[Glycopeptide-resistant Enterococcus outbreak in an ICU with simultaneous circulation of two different clones]

AIM OF THE STUDY

To describe specific difficulties to control a glycopeptide-resistant Enterococcus (GRE) outbreak occurring in an intensive care unit (ICU) during a regional epidemy.

PATIENTS AND METHODS

Following identification of a GRE clinical isolate in ICU, systematic screening was performed on admission and then weekly, by anal swabs. GRE carriers were isolated according to two processes: first (week [W] 2-W8), cohorting of carriers in a dedicated sector of the ICU, with dedicated HCW; this required closing four of the 16 ICU beds. Second (W8-W29), a specific unit was created outside the ICU. VanA-genotypes and pulsed-field gel electrophoresis (PFGE) profiles were analyzed.

RESULTS

During the first outbreak period (102 rectal swabs), two patients were found colonized at admission: the index case transferred from Nancy hospital, carrier of the Nancy epidemy PFGE profile strain, and one patient from the haemodialysis unit, carrier of a GRE strain presenting a different PFGE profile called the Thionville strain. Seven patients were newly identified as GRE colonized (2 by the Nancy strain and 5 by the Thionville strain). Defective running of the ICU was noted. During the second period (442 samples), six ICU patients were found colonized, including four at admission. No other case was identified in 16 weeks. Outbreak extension to other hospital units was checked at W19. The Thionville strain was not found in other regional hospitals.

CONCLUSION

ICUs concentrate GRE colonization risk. This study demonstrates interest of PFGE. These low virulence bacteria have few direct pathological consequences, but they cause organizational problems in ICUs.

Outcomes of colonization with MRSA and VRE among liver transplant candidates and recipients

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) infections cause significant morbidity and mortality among liver transplant candidates and recipients. To assess rates of MRSA and VRE colonization, we obtained active surveillance cultures from 706 liver transplant candidates and recipients within 24 h of admission to an 11-bed liver transplant ICU from October 2000 to December 2005. Patients were followed prospectively to determine the cumulative risk of MRSA or VRE infection or death by colonization status. Outcomes were assessed by Kaplan-Meier survival analysis and Cox regression and multivariate logistic regression adjusting for covariates. The prevalence of newly detected MRSA nasal and VRE rectal colonization was 6.7% and 14.6%, respectively. Liver transplant candidates and recipients with MRSA colonization had an increased risk of MRSA infection (adjusted OR = 15.64, 95% CI 6.63-36.89) but not of death (adjusted OR = 1.00, 95% CI 0.43-2.30), whereas those with VRE colonization had an increased risk both of VRE infection (adjusted OR = 3.61, 95% CI 2.01-6.47) and of death (adjusted OR = 2.12, 95% CI 1.27-3.54) compared with noncolonized patients. Prevention and control strategies, including use of active surveillance cultures, should be implemented to reduce the rates of both MRSA and VRE colonization in this high-risk patient population.

Risk factors for rectal colonization with vancomycin-resistant enterococci in Shiraz, Iran

OBJECTIVES

In order to determine the risk factors for rectal colonization with vancomycin-resistant enterococci (VRE) at the Shiraz Namazi Hospital, we performed a nested case-control study.

METHODS

From December 2003 to July 2004 rectal swabs were taken from 700 randomly selected hospitalized patients every 5 days.

RESULTS

A total of 99 of the 700 patients (14%) were colonized with VRE (cases) and 59 patients were colonized with vancomycin-sensitive strains (VSE), serving as controls. In the univariate analysis, history of antibiotic use (p=0.04), underlying disease (p=0.013), hemodialysis (p=0.03), use of third generation cephalosporins (p=0.04), use of vancomycin (p=0.04), and duration of vancomycin therapy longer than 7 days (p=0.02) were significantly associated with VRE colonization. In a multivariate analysis, underlying disease and the duration of vancomycin use longer than 7 days were independently associated with VRE colonization.

CONCLUSION

Our study, the first on VRE carriage in Iran, demonstrates that VRE prevalence is high in Shiraz and confirms earlier observations in other countries. The identified risk factor 'use of vancomycin longer than 7 days' may be avoidable, indicating a feasible intervention strategy in the control of VRE.

Nosocomial infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococcus: relationships with antibiotic use and cost drivers

BACKGROUND

Increased incidence of nosocomial infections due to methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) has been associated with the use of certain antibiotics and has resulted in increased morbidity, mortality, and costs of care.

OBJECTIVE

To describe relationships between vancomycin and linezolid use and incidence of these nosocomial infections over time and to determine factors associated with the increased costs of care (cost drivers) associated with affected patients.

METHODS

The association between institution-wide antibiotic use and the rate of nosocomial MRSA and VRE infections was assessed using segmented regression analysis for interrupted time series. The effect that patient characteristics and procedures, as well as certain antibiotic use, had on costs and length of stay of patients with MRSA or VRE nosocomial infection was also assessed and cost drivers for the 2 types of infections were compared.

RESULTS

Our analysis included 206 patients who developed MRSA (n = 187) or VRE (n = 19) nosocomial infection. Although small numbers of VRE nosocomial infection may limit generalizations from our results, we found no significant relationship between vancomycin or linezolid use and the rate of either infection. While mean hospital costs were similar, cost drivers varied somewhat between infection types.

CONCLUSIONS

The incidence of MRSA or VRE infections does not appear to be related to the use of vancomycin or linezolid. Costs of care are quite high in some affected patients and, while mean total hospital costs are similar, cost drivers appear to differ between the 2 infection types.

A population-based investigation of invasive vancomycin-resistant Enterococcus infection in metropolitan Atlanta, Georgia, and predictors of mortality

BACKGROUND

Vancomycin-resistant Enterococcus organisms (VRE) have emerged as common nosocomial pathogens, but few population-based data are available on the impact of invasive VRE infections.

METHODS

We assessed the incidence of invasive VRE infections and predictors of mortality among patients identified during prospective, population-based surveillance performed in the metropolitan statistical area (MSA) of Atlanta, Georgia.

RESULTS

From July 1997 through June 2000, a total of 192 patients who resided in the Atlanta MSA developed an invasive VRE infection, for a rate of 1.57 cases per 100,000 person-years. The incidence of invasive VRE disease significantly increased from 0.91 cases per 100,000 person-years during the first year of the study to 1.73 cases per 100,000 person-years during the third year of the study (P<.001). Rates of invasive VRE infection were significantly higher among African American patients than white patients (2.59 vs 0.70 cases per 100,000 person-years; P<.001). Blood was the most common sterile site from which VRE was recovered (161 [83%] of 193 isolates), followed by deep surgical sites (17 [9%]), peritoneal fluid (10 [5%]), pleural fluid (3 [2%]), and cerebrospinal fluid (1 [0.5%]). In multivariate analysis, a Charlson comorbidity index of 5 or greater, previous receipt of antibiotic therapy, having 2 or more sets of blood cultures positive for VRE, and receipt of central parenteral nutrition were independent predictors of mortality, whereas receipt of an antibiotic with in vitro activity against the VRE isolate was associated with a decreased risk of mortality. Molecular typing revealed 38 different pulsed-field gel electrophoresis patterns, but the 2 most common pulsed-field gel electrophoresis types were found at 3 Emory University-affiliated hospitals.

CONCLUSIONS

The incidence of invasive VRE infection significantly increased in the Atlanta MSA during the 3-year study period, with significant racial disparities detected. Receipt of an antimicrobial agent with in vitro activity against VRE was associated with a lower mortality rate. Molecular typing results demonstrated polyclonal emergence of VRE in Atlanta.

Antibiotic-resistant organisms in the neonatal intensive care unit

Neonates, particularly those born prematurely, are at an increased risk of bacterial infection. Empiric treatment with antimicrobials occurs frequently in the neonatal intensive care unit (NICU). Repeated and/or prolonged courses of antibiotic exposure have resulted in an increase in the prevalence of hospital-acquired, antibiotic-resistant organisms such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and multidrug-resistant Gram-negative rods. As bacterial strains become increasingly resistant to standard antimicrobial therapy, measures to control and prevent this problem are essential. Current efforts have focused on monitoring and restricting the use of antimicrobials, proper hand hygiene, evaluation of potential reservoirs of bacterial acquisition and transmission, cohorting and isolation of colonized infants, decolonization strategies, and fostering of effective inter- and intrahospital communication.