Vancomycin-resistant enterococci bacteremia: Risk factors for mortality and influence of antimicrobial therapy on clinical outcome

Increasing trend of healthcare-associated infections due to vancomycin-resistant Enterococcus faecium (VRE-fm) paralleling escalating community-acquired VRE-fm infections in a medical center implementing strict contact precautions: An epidemiologic and pathogenic genotype analysis and its implications

OBJECTIVE

To clarify whether there were clandestine intra-hospital spreads of vancomycin-resistant Enterococcus faecium (VRE-fm) isolates that led to specific strain of VRE lingering in the hospital and/or developing outbreaks that rendered a progressively increasing trend of healthcare-associated infections due to VRE-fm (VRE-fm-HAIs).

SETTING

Despite implementing strict contact precautions for hospitalized patients with VRE-fm-infection/colonization, number of VRE-fm-HAIs in a medical centre in southern Taiwan were escalating in 2009-2019, paralleling an increasing trend of community-acquired VRE-fm- infections.

METHODS

We analyzed epidemiologic data and genotypes of non-duplicate VRE-fm isolates each grown from a normally sterile site of 89 patients between December 2016 and October 2018; multilocus sequence typing (MLST) and pulse-field gel electrophoresis (PFGE) typing were performed.

RESULTS

Totally 13 sequence types (STs) were found, and the 3 leading STs were ST17 (44％), ST78 (37％), and ST18 (6％); 66 pulsotypes were generated by PFGE. Four VRE-fm isolates grouped as ST17/pulsotype S, 2 as ST17/pulsotype AS, 2 as ST17/pulsotype AU, and 3 as ST78/pulsotype V grew from clinical specimens sampled less than one week apart from patients staying at different wards/departments and/or on different floors of the hospital.

CONCLUSIONS

Despite possible small transitory clusters of intra-hospital VRE-fm spreads, there was no specific VRE-fm strain lingering in the hospital leading to increasing trend of VRE-fm-HAIs during the study period. Strict contact precautions were able to curb intra-hospital VRE-fm spreads, but unable to curb the increasing trend of VRE-fm-HAIs with the backdrop of progressively increasing VRE-fm-infections/colorizations in the community.

Cessation of Rectal Screening for Vancomycin-Resistant Enterococci: Experience from a Tertiary Care Hospital from Türkiye

OBJECTIVE

Here, we compared the impact of different polices on the epidemiology of Vancomycin-resistant Enterococcus faecium bloodstream infections (VRE-BSIs) in a tertiary care hospital including two hospital buildings (oncology and adult hospitals) in the same campus.

MATERIAL AND METHODS

All patients who were hospitalized in high-risk units were screened weekly for VRE colonization via rectal swab between January 2006 and January 2013. After January 2013, VRE screening was only performed in cases of suspicion of VRE outbreak and during point prevalence studies to evaluate the epidemiology of VRE colonization. Contact precautions were in place for all VRE-positive patients. The incidence density rates of hospital-acquired (HA)-VRE-BSIs were compared between two periods.

RESULTS

While the rate of VRE colonization was higher in the second period (5% vs. 9.5% (p < 0.01) for the adult hospital, and 6.4% vs. 12% (p = 0.02 for the oncology hospital), there was no increase in the incidence rate HA-VRE BSIs after the cessation of routine rectal screening in either of the hospitals.

CONCLUSION

Screening policies should be dynamic and individualized according to the epidemiology of VRE as well as the workforce and cost. Periodical rectal screening of VRE can be discontinued if suspicion of an outbreak can be carefully monitored.

Molecular Rapid Diagnostics Improve Time to Effective Therapy and Survival in Patients with Vancomycin-Resistant Enterococcus Bloodstream Infections

Delays in appropriate antibiotic therapy are a key determinant for deleterious outcomes among patients with vancomycin-resistant Enterococcus (VRE) bloodstream infections (BSIs). This was a multi-center pre/post-implementation study, assessing the impact of a molecular rapid diagnostic test (Verigene® GP-BC, Luminex Corporation, Northbrook, IL, USA) on outcomes of adult patients with VRE BSIs. The primary outcome was time to optimal therapy (TOT). Multivariable logistic and Cox proportional hazard regression models were used to determine the independent associations of post-implementation, TOT, early vs. delayed therapy, and mortality. A total of 104 patients with VRE BSIs were included: 50 and 54 in the pre- and post-implementation periods, respectively. The post- vs. pre-implementation group was associated with a 1.8-fold faster rate to optimized therapy (adjusted risk ratio, 1.841 [95% CI 1.234-2.746]), 6-fold higher likelihood to receive early effective therapy (<24 h, adjusted odds ratio, 6.031 [2.526-14.401]), and a 67% lower hazards for 30-day in-hospital mortality (adjusted hazard ratio, 0.322 [0.124-1.831]), after adjusting for age, sex, and severity scores. Inversely, delayed therapy was associated with a 10-fold higher risk of in-hospital mortality (aOR 10.488, [2.497-44.050]). Reduced TOT and in-hospital mortality were also observed in subgroups of immunosuppressed patients in post-implementation. These findings demonstrate that the addition of molecular rapid diagnostic tests (mRDT) to clinical microbiology and antimicrobial stewardship practices are associated with a clinically significant reduction in TOT, which is associated with lower mortality for patients with VRE BSIs, underscoring the importance of mRDTs in the management of VRE infections.

Time to Effective Therapy Is an Important Determinant of Survival in Bloodstream Infections Caused by Vancomycin-Resistant Enterococcus spp

Enterococcal bloodstream infections (EBSI) caused by vancomycin-resistant enterococci (VRE) are associated with a significant rate of unfavorable outcomes. No definitive data have been reported about the association between delayed antibiotic therapy and mortality. In this prospective observational study in three large hospitals in Italy (from August 2016 to April 2021), all consecutive hospitalized patients with a confirmed diagnosis of hospital-acquired monomicrobial BSI caused by VRE—with no evidence of endocarditis—were analyzed. Cox regression analysis showed that risk factors independently associated with 30-day mortality were age (HR 2.98, CI95% 1.44−6.81, p = 0.002), chronic kidney disease (HR 5.21, CI95% 1.48−22.23, p = 0.001), oncologic disease (HR 2.81, CI95% 1.45−19.8, p = 0.005), and intensive care unit admission (HR 3.71, CI95% 2.23−7.99, p < 0.001). Conversely, early effective therapy was associated with survival (HR 0.32, CI95% 0.38−0.76, p < 0.001). The administration of early effective antibiotic therapy within 48 h from blood culture collection was associated with 30-day mortality rates lower than 33%. Time from blood culture collection to appropriate therapy was an independent predictor of 30-day mortality in patients with EBSI caused by VRE. Based on these data, clinicians should start effective antibiotic therapy as soon as possible, preferably within the first 48 h from blood culture collection. Treatment strategies allowing the early delivery of in vitro active antibiotics are urgently needed, especially in critically ill patients at risk of VRE bacteremia.

Does Vancomycin Resistance Increase Mortality? Clinical Outcomes and Predictive Factors for Mortality in Patients with Enterococcus faecium Infections

The prevalence of enterococcal infection, especially E. faecium, is increasing, and the issue of the impact of vancomycin resistance on clinical outcomes is controversial. This study aimed to investigate the clinical outcomes of infection caused by E. faecium and determine the risk factors associated with mortality. This retrospective study was performed at the Phramongkutklao Hospital during the period from 2014 to 2018. One hundred and forty-five patients with E. faecium infections were enrolled. The 30-day and 90-day mortality rates of patients infected with vancomycin resistant (VR)-E. faecium vs. vancomycin susceptible (VS)-E. faecium were 57.7% vs. 38.7% and 69.2% vs. 47.1%, respectively. The median length of hospitalization was significantly longer in patients with VR-E. faecium infection. In logistic regression analysis, VR-E. faecium, Sequential Organ Failure Assessment (SOFA) scores, and bone and joint infections were significant risk factors associated with both 30-day and 90-day mortality. Moreover, Cox proportional hazards model showed that VR-E. faecium infection (HR 1.91; 95%CI 1.09–3.37), SOFA scores of 6–9 points (HR 2.69; 95%CI 1.15–6.29), SOFA scores ≥ 10 points (HR 3.71; 95%CI 1.70–8.13), and bone and joint infections (HR 0.08; 95%CI 0.01–0.62) were significant risk factors for mortality. In conclusion, the present study confirmed the impact of VR-E. faecium infection on mortality and hospitalization duration. Thus, the appropriate antibiotic regimen for VR-E. faecium infection, especially for severely ill patients, is an effective strategy for improving treatment outcomes.

An Update to Enterococcal Bacteremia: Epidemiology, Resistance, and Outcome

BACKGROUND

An increase in resistant gram-positive cocci, especially enterococci, requires an epidemiologic re-assay and its results may affect empirical treatments for these infections.

OBJECTIVE

In this study, we investigated the microbial epidemiology and resistance pattern of enterococcal bacteremia.

METHODS

This study was a cross-sectional study that investigates all cases of positive blood cultures with Enterococcus spp. at a tertiary referral colligates hospital in Tehran in 2018.

RESULTS

Enterococcus spp. was isolated from blood cultures of a total of 73 patients. The most patients were male 42 (57.7%). The mean age of the patients was 58.8 (±18.8) years. Hospital-acquired infection was the most type of infection involving enterococcal bacteremia (80.8%) comparing with community-acquired (6.7%) and health care-associated (12.3%). Renal failure and cancer were the most underlying disease in E. faecalis and E. faecium, respectively. Mortality for Vanco-mycin-resistant enterococci (VRE) was approximately two times more than the sensitive ones. Between the dead/alive groups, the following items were different significantly (P.Value<0.05): Vancomycin resistance for enterococcus isolated, immunodeficiency as underlying disease, Mechanical ventilation, hospitalization period, and the empiric regimen.

CONCLUSION

Increased antibiotic-resistant strains, especially Vancomycin-resistant enterococci (VRE), pose a serious threat to the general public, especially hospitalized patients, and increase mortality. Surveillance of microorganisms and antimi-crobial resistance is a crucial part of an efficient health care system.

Predictors of Mortality in Patients with Carbapenem-Resistant Gram-Negative Bacilli or Vancomycin-Resistant Enterococci Bacteremia

Purpose

The incidences of carbapenem-resistant gram-negative bacilli (CRGNB) and vancomycin-resistant Enterococci (VRE) have increased rapidly in South Korea since 2000. The mortality rate for CRGNB or VRE bacteremia cases is higher than that for non-resistant bacteremia cases. The factors associated with higher mortality are unclear. We investigated the factors associated with mortality from CRGNB or VRE bacteremia and compared the relative risk of these factors.

Patients and Methods

We retrospectively collected data from adult patients with CRGNB or VRE bacteremia. Patients were grouped according to whether they survived or died. The data from both groups were compared.

Results

During the study period, 171 cases of CRGNB or VRE bacteremia were identified, of which 100 were CRGNB bacteremia cases and 71 were VRE bacteremia cases. Multivariate analysis revealed significant associations with Pitt bacteremia score (PBS) (odds ratio [OR] 1.329, 95% confidence interval [CI] 1.049-1.684). In the multivariate analysis, negative conversion of follow-up blood culture (FUBC) was related with one-week mortality from CRGNB or VRE bacteremia (OR 17.623, 95% CI 5.726-54.244). In the multivariate analysis of risk factors for 28-day mortality for CRGNB or VRE bacteremia, the significant risk factors were bacteremia of respiratory origin (OR 4.491, 95% CI 1.622-12.435) and positive FUBC (OR 4.082, 95% CI 1.626-10.204).

Conclusion

Despite the high mortality rate in patients with CRGNB or VRE bacteremia, the related mortality could be predicted by independent risk factors of PBS, positive FUBC, and bacteremia of respiratory origin.

Epidemiology, treatment and outcomes of bloodstream infection due to vancomycin-resistant enterococci in cancer patients in a vanB endemic setting

Background

Vancomycin-resistant enterococcus (VRE) is an important cause of infection in immunocompromised populations. Few studies have described the characteristics of vanB VRE infection. We sought to describe the epidemiology, treatment and outcomes of VRE bloodstream infections (BSI) in a vanB predominant setting in malignant hematology and oncology patients.

Methods

A retrospective review was performed at two large Australian centres and spanning a 6-year period (2008–2014). Evaluable outcomes were intensive care admission (ICU) within 48 h of BSI, all-cause mortality (7 and 30 days) and length of admission.

Results

Overall, 106 BSI episodes were observed in 96 patients, predominantly Enterococcus faecium vanB (105/106, 99%). Antibiotics were administered for a median of 17 days prior to BSI, and 76/96 (79%) were neutropenic at BSI onset. Of patients screened before BSI onset, 49/72 (68%) were found to be colonised. Treatment included teicoplanin (59), linezolid (6), daptomycin (2) and sequential/multiple agents (21). Mortality at 30-days was 31%. On multivariable analysis, teicoplanin was not associated with mortality at 30 days.

Conclusions

VRE BSI in a vanB endemic setting occurred in the context of substantive prior antibiotic use and was associated with high 30-day mortality. Targeted screening identified 68% to be colonised prior to BSI. Teicoplanin therapy was not associated with poorer outcomes and warrants further study for vanB VRE BSI in cancer populations.

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).

Temporal and Geographic Variation in Antimicrobial Susceptibility and Resistance Patterns of Enterococci: Results From the SENTRY Antimicrobial Surveillance Program, 1997-2016

Background

The SENTRY Antimicrobial Surveillance Program was established in 1997 and presently encompasses more than 750 000 bacterial isolates from over 400 medical centers worldwide. Among these pathogens, enterococci represents a prominent cause of bloodstream (BSIs), intra-abdominal (IAIs), skin and skin structure, and urinary tract infections (UTIs). In the present study, we reviewed geographic and temporal trends in Enterococcus species and resistant phenotypes identified throughout the SENTRY Program.

Methods

From 1997 to 2016, a total of 49 491 clinically significant enterococci isolates (15 species) were submitted from 298 medical centers representing the Asia-Pacific (APAC), European, Latin American (LATAM), and North American (NA) regions. Bacteria were identified by standard algorithms and matrix-assisted laser desorption ionization–time of flight mass spectrometry. Susceptibility (S) testing was performed by reference broth microdilution methods and interpreted using Clinical and Laboratory Standards Institute/US Food and Drug Administration and European Committee on Antimicrobial Susceptibility Testing criteria.

Results

The most common Enterococcus species in all 4 regions were Enterococcus faecalis (64.7%) and E. faecium (EFM; 29.0%). Enterococci accounted for 10.7% of BSIs in NA and was most prominent as a cause of IAIs (24.0%) in APAC and of UTIs (19.8%) in LATAM. A steady decrease in the susceptibility to ampicillin and vancomycin was observed in all regions over the 20-year interval. Vancomycin-resistant enterococci (VRE) accounted for more than 8% of enterococcal isolates in all regions and was most common in NA (21.6%). Among the 7615 VRE isolates detected, 89.1% were the VanA phenotype (91.0% EFM) and 10.9% were VanB. Several newer antimicrobial agents demonstrated promising activity against VRE, including daptomycin (99.6–100.0% S), linezolid (98.0%–99.6% S), oritavancin (92.2%–98.3% S), tedizolid (99.5%–100.0% S), and tigecycline (99.4%–100.0% S).

Conclusions

Enterococci remained a prominent gram-positive pathogen in the SENTRY Program from 1997 through 2016. The overall frequency of VRE was 15.4% and increased over time in all monitored regions. Newly released agents with novel mechanisms of action show promising activity against VRE.

Enterococcal bacteremia in febrile neutropenic children and adolescents with underlying malignancies, and clinical impact of vancomycin resistance

PURPOSE

Enterococci are a common cause of bacteremia in immunocompromised patients. Although the increase of vancomycin-resistant enterococci (VRE) makes appropriate antibiotic therapy difficult, clinical characteristics of enterococcal bacteremia and the impact of VRE infection on outcomes have rarely been reported in immunocompromised children.

METHODS

We enrolled children and adolescents (< 19 years of age) with underlying malignancies who were diagnosed with enterococcal bacteremia during febrile neutropenia between 2010 and 2017. Medical records of the enrolled children were retrospectively reviewed to evaluate the clinical characteristics of enterococcal bacteremia and impact of VRE infection on outcomes.

RESULTS

Thirty-six episodes of enterococcal bacteremia were identified in 30 patients. VRE infection was identified in 11 episodes (30.6%); the 7- and 30-day mortalities were 27.8% and 44.4%, respectively. Acute lymphoblastic leukemia (50.0%) and acute myeloid leukemia (30.6%) were the most common underlying disorders. Three (8.3%) of the patients were in complete remission, and palliative and reinduction chemotherapies were administered in 47.2% and 36.1% of episodes, respectively. Empirical antibiotic therapy was appropriate in 64.0% of patients with vancomycin-susceptible enterococcal infection and in none of the VRE-infected patients (p = 0.001). However, the 30-day mortality was not significantly different between the two patient groups (44.0% vs. 45.5%, p = 1.000).

CONCLUSIONS

Most episodes of enterococcal bacteremia occurred in advanced stages of underlying malignancies, and still showed high mortality. The prognosis seemed to be related to the underlying disease condition rather than vancomycin resistance of the isolated enterococci, although the number of enrolled patients was small.

Impact on Public Health of the Spread of High-Level Resistance to Gentamicin and Vancomycin in Enterococci

Antibiotic resistance has turned into a global public health issue. Enterococci are intrinsically resistant to many antimicrobials groups. These bacteria colonize dairy and meat products and integrate the autochthonous microbiota of mammal's gastrointestinal tract. Over the last decades, detection of vanA genotype in Enterococcus faecium from animals and from food of animal origin has been reported. Vancomycin-resistant E. faecium has become a prevalent nosocomial pathogen. Hospitalized patients are frequently treated with broad-spectrum antimicrobials and this leads to an increase in the presence of VanA or VanB vancomycin-resistant enterococci in patients' gastrointestinal tract and the risk of invasive infections. In humans, E. faecium is the main reservoir of VanA and VanB phenotypes. Acquisition of high-level aminoglycoside resistance is a significant therapeutic problem for patients with severe infections because it negates the synergistic effect between aminoglycosides and a cell-wall-active agent. The aac(6')-Ie-aph (2″)-Ia gene is widely spread in E. faecalis and has been detected in strains of human origin and in the food of animal origin. Enzyme AAC(6')-Ie-APH(2″)-Ia confers resistance to available aminoglycosides, except to streptomycin. Due to the fast dissemination of this genetic determinant, the impact of its horizontal transferability among enterococcal species from different origin has been considered. The extensive use of antibiotics in food-producing animals contributes to an increase in drug-resistant animal bacteria that can be transmitted to humans. Innovation is needed for the development of new antibacterial drugs and for the design of combination therapies with conventional antibiotics. Nowadays, semi-purified bacteriocins and probiotics are becoming an attractive alternative to the antibiotic in animal production. Therefore, a better understanding of a complex and relevant issue for Public Health such as high-level vancomycin and gentamicin resistance in enterococci and their impact is needed. Hence, it is necessary to consider the spread of vanA E. faecium and high-level gentamicin resistant E. faecalis strains of different origin in the environment, and also highlight the potential horizontal transferability of these resistance determinants to other bacteria.

Patient- and hospital-level predictors of vancomycin-resistant Enterococcus (VRE) bacteremia in Ontario, Canada

BACKGROUND

Data are limited on risk factors for vancomycin-resistant Enterococcus (VRE) bacteremia.

METHODS

All patients with a confirmed VRE bacteremia in Ontario, Canada, between January 2009 and December 2013 were linked to provincial healthcare administrative data sources and frequency matched to 3 controls based on age, sex, and aggregated diagnosis group. Associations between predictors and VRE bacteremia were estimated by generalized estimating equations and summarized using odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

RESULTS

In total, 217 cases and 651 controls were examined. In adjusted analyses, patient-level predictors included bone marrow transplant (OR 106.99 [95% CI 12.19-939.26]); solid organ transplant (OR 17.17 [95% CI 4.95-59.54]); any cancer (OR 8.64 [95% CI 3.88-19.21]); intensive care unit (ICU) admission (OR 6.81 [95% CI 3.53-13.13]); heart disease (OR 5.27 [95% CI 2.00-13.90]); and longer length of stay (OR 1.07 per day [95% CI 1.06-1.09]). Hospital-level predictors included hospital size (per increase in 100 beds (OR 1.26 [95% CI 1.07-1.48]) and teaching hospitals (OR 3.87 [95% CI 1.85-8.08]).

CONCLUSIONS

Patients with a bone marrow transplant, solid organ transplant, cancer, or who are admitted to the ICU are at highest risk of VRE bacteremia, particularly at large hospitals and teaching hospitals.

In vitro activity of salicylamide derivatives against vancomycin-resistant enterococci

A series of 13 salicylamide derivatives was assessed for antibacterial activity against three isolates of vancomycin-resistant Enterococcus faecalis (VRE) and Enterococcus faecalis ATCC 29212 as a quality standard. The minimum inhibitory concentration was determined by the broth microdilution method with subsequent subcultivation of aliquots to assess minimum bactericidal concentration. The growth kinetics was established by the time-kill assay. Ampicillin, ciprofloxacin, tetracycline and vancomycin were used as the reference antibacterial drugs. Three of the investigated compounds showed strong bacteriostatic activity against VRE (0.199-25 µM) comparable to or more potent than ampicillin and ciprofloxacin. In addition, these compounds were tested for synergistic effect with vancomycin, ciprofloxacin and tetracycline, while 5-chloro-2-hydroxy-N-[4-(trifluoromethyl)phenyl]benzamide showed the highest potency as well as synergistic activity with vancomycin against VRE 368. Screening of the cytotoxicity of the most effective compounds was performed using human monocytic leukemia THP-1 cells, and based on LD₅₀ values, it can be stated that the compounds have insignificant toxicity against human cells.

Clinical characteristics and treatment outcomes of vancomycin-resistant Enterococcus faecium bacteremia

BACKGROUND

Vancomycin-resistant Enterococcus faecium (VRE-fm) bacteremia causes significant mortality in hospitalized patients. We sought to investigate clinical characteristics, treatment outcomes, and microbiological eradication associated with VRE-fm bacteremia.

METHODS

A retrospective cohort study was conducted and included 210 adult patients admitted between January 1, 2011 and December 31, 2015.

RESULTS

The mean Pitt bacteremia score was 4.7. ICU stay (48.6%) and mechanical ventilation (46.2%) were common. Diabetes mellitus was the most common concomitant disease (43.3%), followed by malignancies, including hematologic malignancies (14.3%) and solid cancers (28.1%). The 14-day and 28-day mortality rates were 37.1% and 50.5%, respectively. Linezolid or daptomycin treatment for at least 10 days and higher Pitt bacteremia scores were independently associated with 14-day and 28-day mortality. Longer treatment duration of linezolid or daptomycin predicted microbiological eradication independently. Daptomycin-treated patients tended to have higher 14-day and 28-day mortality, and lower microbial eradication rates (20.8% versus 8.7%; 40.6% versus 26.1%; 14.1% versus 26.1%; respectively) than linezolid-treated patients, and cumulative survival rates at 14 and 28 days tended to be lower in patients who received low-dose daptomycin (<10 mg/kg/day) than that in those who received linezolid and high-dose daptomycin (≥10 mg/kg/day); however, the differences were not statistically significant.

CONCLUSION

Higher disease severity and inappropriate treatment were associated with increased mortality and longer treatment duration of linezolid or daptomycin was associated with microbial eradication for the patient with VRE-fm bacteremia.

Time Is of the Essence: The Impact of Delayed Antibiotic Therapy on Patient Outcomes in Hospital-Onset Enterococcal Bloodstream Infections

BACKGROUND

With increasing prevalence of vancomycin-resistant enterococci (VRE), appropriate antibiotic therapy for enterococcal bloodstream infections (EBSI) can be delayed. Data regarding the impact of delayed therapy on EBSI outcomes are conflicting, and the time delay most strongly associated with poor outcomes has not been defined.

METHODS

This was a single-center, retrospective cohort study of adult, nonneutropenic patients with hospital-onset EBSI from 2010 to 2014. Classification and regression tree (CART) analysis was used to determine the delay in appropriate therapy most predictive of 30-day mortality. Appropriate therapy was defined as antibiotic therapy to which the enterococci and copathogen, where applicable, were susceptible. Outcomes and clinical characteristics were compared between patients receiving early or delayed therapy, defined by CART timepoint. Poisson regression was employed to determine the independent association of delayed therapy on 30-day mortality and predictors of delayed therapy.

RESULTS

Overall, 190 patients were included. A breakpoint in time to appropriate therapy was identified at 48.1 hours, where 30-day mortality was substantially increased (14.6% vs 45.3%; P < .001). Patients receiving appropriate therapy after 48.1 hours also experienced higher in-hospital mortality and longer EBSI duration. After adjustment for severity of illness and comorbidity, delayed therapy ≥48.1 hours was associated with a 3-fold increase in 30-day mortality (risk ratio, 3.16 [95% confidence interval, 1.96-5.09]). Vancomycin resistance was the only independent predictor of delayed therapy.

CONCLUSIONS

In patients with hospital-onset EBSI, receipt of appropriate therapy within the first 48 hours was associated with reduced mortality, underscoring the potential role of rapid diagnostic testing for early identification of VRE.

Infection control and prevention considerations

Due to the nature of their underlying illness and treatment regimens, cancer patients are at increased risk of infection. Though the advent and widespread use of anti-infective agents has allowed for the application of ever-greater immune-suppressing therapies with successful treatment of infectious complications, prevention of infection remains the primary goal. The evolutionary changes of microorganisms, whereby resistance to anti-infective therapy is increasingly common, have facilitated a paradigm shift in the field of healthcare epidemiology. No longer is the focus on "control" of infection once established in a healthcare environment. Rather, the emphasis is on prevention of infection before it occurs. The most basic tenet of infection prevention, and the cornerstone of all well-designed infection prevention and control programs, is hand hygiene. The hands of healthcare workers provide a common potential source for transmission of infectious agents, and effective decontamination of the hands reduces the risk of transmission of infectious material to other patients. Once infection is suspected or established; however, implementation of effective control strategies is important to limit the spread of infection within a healthcare environment. This chapter outlines the basic tenets of infection prevention, principles of isolation precautions and control measures, and elements for a successful infection control and prevention program.

Systematic review and meta-analysis of linezolid versus daptomycin for treatment of vancomycin-resistant enterococcal bacteremia

Limited therapeutic options exist for the treatment of vancomycin-resistant Enterococcus (VRE) bacteremia; the most commonly used are daptomycin and linezolid. We attempted a systematic review and meta-analysis of the comparative efficacy of those two agents. Studies comparing daptomycin to linezolid treatment for VRE bacteremia, published until August 2012, were identified from the MEDLINE, EMBASE, CENTRAL, ISI Web of Science, and SCOPUS databases. All comparative studies on patients older than 18 years of age that provided mortality data were considered eligible for this systematic review and meta-analysis. Τhe primary outcome of the meta-analysis was 30-day all-cause mortality. Ten retrospective studies including 967 patients were identified. Patients treated with daptomycin had significantly higher 30-day all-cause mortality (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.08 to 2.40) and infection-related mortality (OR, 3.61; 95% CI, 1.42 to 9.20) rates than patients treated with linezolid. When data from all 10 studies were combined, overall mortality was also significantly increased among patients treated with daptomycin (OR, 1.41; 95% CI, 1.06 to 1.89). These findings were confirmed when odds ratios adjusted for potential confounders were pooled. Relapse rates among patients treated with daptomycin were also higher (OR, 2.51; 95% CI, 0.94 to 6.72), although this difference did not reach statistical significance. Adverse event rates were not significantly different between the two groups. Notwithstanding the absence of randomized prospective data, available evidence suggests that mortality rates may be higher with daptomycin than with linezolid among patients treated for VRE bacteremia.

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.

Incidence, clinical characteristics and 30-day mortality of enterococcal bacteraemia in Denmark 2006-2009: a population-based cohort study

Enterococci currently account for approximately 10% of all bacteraemias, reflecting remarkable changes in their epidemiology. However, population-based data of enterococcal bacteraemia are scarce. A population-based cohort study comprised all patients with a first episode of Enterococcus faecalis or Enterococcus faecium bacteraemia in two Danish regions during 2006-2009. We used data collected prospectively during clinical microbiological counselling and hospital registry data. We determined the incidence of mono- and polymicrobial bacteraemia and assessed clinical and microbiological characteristics as predictors of 30-day mortality in monomicrobial bacteraemia by logistic regression analysis. We identified 1145 bacteraemic patients, 700 (61%) of whom had monomicrobial bacteraemia. The incidence was 19.6/100 000 person-years (13.0/100 000 person-years for E. faecalis and 6.6/100 000 person-years for E. faecium). The majority of bacteraemias were hospital-acquired (E. faecalis, 45.7%; E. faecium, 85.2%). Urinary tract and intra-abdominal infections were the predominant foci for the two species, respectively. Infective endocarditis (IE) accounted for 25% of patients with community-acquired E. faecalis bacteraemia. Thirty-day mortality was 21.4% in patients with E. faecalis and 34.6% in patients with E. faecium. Predictors of 30-day mortality included age, co-morbidity and hospital-acquired bacteraemia. In addition, intra-abdominal infection, unknown focus and high-level gentamicin resistance were predictors of mortality in E. faecalis patients. E. faecium was associated with increased risk of mortality compared with E. faecalis. The study emphasizes the importance of enterococci both in terms of incidence and prognosis. The frequency of IE in patients with E. faecalis bacteraemia emphasizes the importance of echocardiography, especially in community-acquired cases.

Antimicrobial resistance in Asia: current epidemiology and clinical implications

Antimicrobial resistance has become one of the most serious public health concerns worldwide. Although circumstances may vary by region or country, it is clear that some Asian countries are epicenters of resistance, having seen rapid increases in the prevalence of antimicrobial resistance of major bacterial pathogens. In these locations, however, the public health infrastructure to combat this problem is very poor. The prevalence rates of methicillin-resistant Staphylococcus aureus (MRSA), macrolide-resistant Streptococcus pneumoniae, and multidrug-resistant enteric pathogens are very high due to the recent emergence of extremely drug-resistant gram-negative bacilli in Asia. Because antimicrobial options for these pathogens are extremely limited, infections caused by antimicrobial-resistant bacteria are often associated with inappropriate antimicrobial therapy and poor clinical outcomes. Physicians should be aware of the current epidemiological status of resistance and understand the appropriate use of antimicrobial agents in clinical practice. This review focuses on describing the epidemiology and clinical implications of antimicrobial-resistant bacterial infections in Asian countries.

Enterococcal bacteraemia: factors influencing mortality, length of stay and costs of hospitalization

Enterococci are a major cause of nosocomial bacteraemia. The impacts of vanB vancomycin resistance and antibiotic therapy on outcomes in enterococcal bacteraemia are unclear. Factors that affect length of stay (LOS) and costs of managing patients with enterococcal bacteraemia are also unknown. This study aimed to identify factors associated with mortality, LOS and hospitalization costs in patients with enterococcal bacteraemia and the impact of vancomycin resistance and antibiotic therapy on these outcomes. Data from 116 patients with vancomycin-resistant Enterococci (VRE), matched 1:1 with patients with vancomycin-susceptible Enterococcus (VSE), from two Australian hospitals were reviewed for clinical and economic outcomes. Univariable and multivariable logistic and quantile regression analyses identified factors associated with mortality, LOS and costs. Intensive care unit admission (OR, 8.57; 95% CI, 3.99-18.38), a higher burden of co-morbidities (OR, 4.55; 95% CI, 1.83-11.33) and longer time to appropriate antibiotics (OR, 1.02; 95% CI, 1.01-1.03) were significantly associated with mortality in enterococcal bacteraemia. VanB vancomycin resistance increased LOS (4.89 days; 95% CI, 0.56-11.52) and hospitalization costs (AU$ 28 872; 95% CI, 734-70 667), after adjustment for confounders. Notably, linezolid definitive therapy was associated with lower mortality (OR, 0.13; 95% CI, 0.03-0.58) in vanB VRE bacteraemia patients. In patients with VSE bacteraemia, time to appropriate antibiotics independently influenced mortality, LOS and hospitalization costs, and underlying co-morbidities were associated with mortality. The study findings highlight the importance of preventing VRE bacteraemia and the significance of time to appropriate antibiotics in the management of enterococcal bacteraemia.

Evaluation of the Treatment of Vancomycin-Resistant Enterococcal Urinary Tract Infections in a Large Academic Medical Center

BACKGROUND:

Vancomycin-resistant enterococci (VRE) are a common cause of nosocomial urinary tract infections (UTIs) among hospitalized patients. Clinicians need to differentiate between VRE-associated urinary colonization, asymptomatic bacteriuria, and UTIs to determine the need for treatment and length of therapy.

OBJECTIVE:

To characterize the diagnosis and management of VRE from urinary sources, including compliance with institutional treatment guidelines, and identify risk factors associated with clinical failure.

METHODS:

We performed a retrospective, single-center, cohort study among patients with VRE-positive cultures from urinary sources over a 3-year study period (July 2008-September 2011). Descriptive statistics were used to evaluate demographics, diagnostics, guideline compliance, pharmacotherapy, and outcomes. Risk factors associated with clinical failure were identified by multivariate logistic regression analysis.

RESULTS:

Two hundred sixty-nine distinct episodes of VRE met inclusion criteria among 252 patients. Forty-seven percent and 77% of episodes occurred in patients admitted to an intensive care unit and hospitalized for 7 or more days, respectively. Fifty-eight percent of the episodes were classified as asymptomatic bacteriuria or colonization. Compliance with institutional treatment guidelines for the appropriate drug, dose, and duration occurred in approximately 70% of the cases. Among noncompliant cases (n = 83), 48 (58%) were overtreated, and 35 (42%) were undertreated. Clinical failure among all cases was common, including mortality (17.1%). Factors independently associated with clinical failure determined on multivariate analysis included weight 100 kg or more (OR 5.30; 95% CI 1.42–12.21; p = 0.014), renal disease (OR 2.57; 95% CI 1.02–6.47; p = 0.048), indwelling catheter (OR 4.62; 95% CI 1.05–18.24; p = 0.046), and VRE bloodstream infection (OR 15.71; 95% CI 2.9–128.7; p < 0.001).

CONCLUSIONS:

Improved education is needed to minimize cases of overtreatment and undertreatment of VRE-associated UTIs and decrease inappropriate drug-related costs and clinical failure rates. Risk factors for clinical failure can be used to risk stratify VRE-associated UTIs and further guide treatment decisions.

Evaluation of a daptomycin dose-optimization protocol

PURPOSE

The impact of an institutional protocol intended to improve daptomycin dosing for vancomycin-resistant enterococci (VRE) infections was investigated.

SUMMARY

Daptomycin has been reported to have optimal activity against VRE at weight-based doses of ≥8 mg/kg. As part of an initiative to optimize daptomycin dosing for all indications and regimens, a large medical center implemented a protocol restricting daptomycin prescribing to infectious-diseases specialists and a nomogram recommending elevated daptomycin dosing for all VRE infections, with baseline and weekly creatinine phosphokinase (CPK) determinations during daptomycin therapy. Protocol implementation was preceded by educational efforts targeting medical and pharmacy staff. A retrospective study was conducted to compare prescribing behavior and safety monitoring rates during the 12 months before and 16 months after protocol implementation; the baseline characteristics of the preimplementation cohort (n = 95) and postimplementation cohort (n = 72) were similar. The mean daptomycin doses before and after the protocol was implemented were 453 mg (6.1 mg/kg) and 576 mg (7.6 mg/kg), respectively. After protocol implementation, there were significant increases in the proportion of patients who received doses of ≥8 mg/kg (52% in the postimplementation period versus 4% in the preimplementation period, p < 0.05) and in the rate of baseline CPK assessment (64% versus 43%, p < 0.05).

CONCLUSION

Implementation of a daptomycin dosing protocol by a multidisciplinary antimicrobial stewardship team optimized treatment by increasing the mean dose of daptomycin administered to hospitalized adults with non-urinary VRE infections and improved the rate of safety monitoring.

Outcomes of therapy: vancomycin-resistant enterococcal bacteremia in hematology and bone marrow transplant patients

PURPOSE

The purpose of this study was to evaluate the risk factors associated with the treatment failure and 30-day mortality in hematology and bone marrow transplant patients treated with daptomycin or linezolid for vancomycin-resistant enterococci (VRE) bacteremia. The safety and tolerability of therapy was also assessed.

METHODS

This single-center, retrospective study included adult patients admitted to the hematology or bone marrow transplant service with documented vancomycin-resistant Enterococcus faecium or Enterococcus faecalis bacteremia and received at least 48 h of either linezolid or daptomycin as primary treatment. Clinical and microbiologic outcomes were assessed at day 7, 14, and 30 of hospital stay.

RESULTS

A total of 72 patients were included in the analysis. Forty-three patients received daptomycin as primary treatment and 29 received linezolid as primary treatment. Overall success rate at day 7 was 81.9%, day 14 success rate was 79.2%, and day 30 success rate was 76.4% for all patients. Forty-one patients (57.0%) had high-grade bacteremia defined as greater than one positive blood culture for VRE. The mortality rate was significantly higher if high-grade bacteremia was present (34.1% vs. 7.0%; p = 0.009).

CONCLUSIONS

This study suggests that linezolid and daptomycin are both reasonable options for treating VRE bacteremia in hematology and bone marrow transplant patients; however, patients with high-grade VRE bacteremia may be at increased risk for treatment failure.

Fatal vancomycin- and linezolid-resistant Enterococcus faecium sepsis in a child undergoing allogeneic haematopoietic stem cell transplantation for beta-thalassaemia major

Recently vancomycin-resistant and sporadically linezolid-resistant Enterococcus species have been described in adults. We report what we believe to be the first case of a child with prolonged bone marrow aplasia following haematopoietic stem cell transplantation developing a fatal sepsis caused by Enterococcus faecium resistant to glycopeptides and linezolid.

Survival after intestinal perforation: can it be predicted?

OBJECTIVE

Intestinal perforation is associated with high morbidity and mortality in gynecologic oncology patients. We investigated potential factors associated with survival after perforation which may influence treatment recommendations.

METHODS

A retrospective review of all gynecologic oncology patients experiencing intestinal perforation between 1993 and 2007 was performed. Demographics, cancer history, presenting symptoms, vital signs, laboratory values, and management of perforation were collected, and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were calculated for each patient. Factors affecting survival from the time of perforation were analyzed using Kaplan-Meier method and univariate and multivariate Cox proportional hazard models. Student's t-test and chi(2) analysis were also utilized to evaluate potential associations.

RESULTS

Fifty-three patients met the inclusion criteria. No difference in survival was found based on disease site, history of radiation therapy, presenting symptoms, smoking history, or presence of bowel procedures performed during the most recent abdominal surgery prior to perforation. APACHE II score, disease status, body mass index, and treatment method of perforation were found to be significant prognostic factors for survival. After multivariate Cox regression analysis, only APACHE II scores remained significantly associated with an increased risk of death. Median survival of patients with APACHE II scores <15 was 28.13 months compared to 2.90 months in patients with scores> or =15 (P<0.0001).

CONCLUSION

Many factors must be examined when determining the management of intestinal perforation in gynecologic oncology patients. Clinicians should consider the APACHE II score in their assessment to assist risk stratification and treatment planning of these patients.