Intensified strategies to control vancomycin-resistant enterococci in immunocompromised patients

Healthcare-associated infections over an eight year period in a large university hospital in Sicily (Italy, 2011-2018)

Background

Up to 7% of hospitalised patients acquire at least one healthcare-associated infection (HAI). The aim of the present study was to quantify the burden of HAIs in an Italian hospital, identifying involved risk factors.

Methods

Prevalence point study carried out from 2011 to 2018. For each recruited patient, a data entry form was compiled including information on demographics, hospital admission, risk factors, antimicrobial treatment, and infection if present.

Results

A total of 2844 patients were included and 218 (7.03%) reported an infection. HAI prevalence rates showed a significant increase (average annual per cent change (AAPC) +33.9%; p=0.018) from 2011 to 2014 whereas from 2014 to 2018 a gradual decline was observed (AAPC -6.15%; p=0.35). Urinary tract infection was the most common HAI (25.2%) and a total of 166 (76.1%) pathogens were isolated from 218 infections. Enterococcus and Klebsiella species were the most prevalent pathogens, causing 15.1% and 14.5% of HAIs, respectively. A significant higher risk of HAIs was found in patients exposed to central catheter (adjusted odds ratio (adj-OR)=5.40), peripheral catheter (adj-OR=1.89), urinary catheter (adj-OR=1.46), National Healthcare Safety Network surgical intervention (adj-OR=1.48), ultimately fatal disease (adj-OR=2.19) or rapidly fatal disease (adj-OR=2.09) and in patients with longer hospital stay (adj-OR=1.01).

Conclusion

Intervention programmes based on guidelines dissemination and personnel training can contribute to reduce the impact of HAI. Moreover, McCabe score can be a very powerful and efficient predictor of risk for HAI. Finally, an unexpected very high burden of disease due to Enterobacteriaceae and Gram positive cocci that could be related to the frequent use of carbapenems and third generation cephalosporins in this hospital was found.

A systematic review of the effectiveness of cohorting to reduce transmission of healthcare-associated C. difficile and multidrug-resistant organisms

BACKGROUND

Cohorting of patients and staff is a control strategy often used to prevent the spread of infection in healthcare institutions. However, a comprehensive evaluation of cohorting as a prevention approach is lacking.

METHODS

We performed a systematic review of studies that used cohorting as part of an infection control strategy to reduce hospital-acquired infections. We included studies published between 1966 and November 30, 2019, on adult populations hospitalized in acute-care hospitals.

RESULTS

In total, 87 studies met inclusion criteria. Study types were quasi-experimental "before and after" (n = 35), retrospective (n = 49), and prospective (n = 3). Case-control analysis was performed in 7 studies. Cohorting was performed with other infection control strategies in the setting of methicillin-resistant Staphylococcus aureus (MRSA, n = 22), Clostridioides difficile infection (CDI, n = 6), vancomycin-resistant Enterococcus (VRE, n = 17), carbapenem-resistant Enterobacteriaceae infections (CRE, n = 22), A. baumannii (n = 15), and other gram-negative infections (n = 5). Cohorting was performed either simultaneously (56 of 87, 64.4%) or in phases (31 of 87, 35.6%) to help contain transmission. In 60 studies, both patients and staff were cohorted. Most studies (77 of 87, 88.5%) showed a decline in infection or colonization rates after a multifaceted approach that included cohorting as part of the intervention bundle. Hand hygiene compliance improved in approximately half of the studies (8 of 15) during the respective intervention.

CONCLUSION

Cohorting of staff, patients, or both is a frequently used and reasonable component of an enhanced infection control strategy. However, determining the effectiveness of cohorting as a strategy to reduce transmission of MDRO and C. difficile infections is difficult, particularly in endemic situations.

Thirty years of VRE in Germany - "expect the unexpected": The view from the National Reference Centre for Staphylococci and Enterococci

Enterococci are commensals of the intestinal tract of many animals and humans. Of the various known and still unnamed new enterococcal species, only isolates of Enterococcus faecium and Enterococcus faecalis have received increased medical and public health attention. According to textbook knowledge, the majority of infections are caused by E. faecalis. In recent decades, the number of enterococcal infections has increased, with the increase being exclusively associated with a rising number of nosocomial E. faecium infections. This increase has been accompanied by the dissemination of certain hospital-acquired strain variants and an alarming progress in the development of antibiotic resistance namely vancomycin resistance. With this review we focus on a description of the specific situation of vancomycin resistance among clinical E. faecium isolates in Germany over the past 30 years. The present review describes three VRE episodes in Germany, each of which is framed by the beginning and end of the respective decade. The first episode is specified by the first appearance of VRE in 1990 and a country-wide spread of specific vanA-type VRE strains (ST117/CT24) until the late 1990s. The second decade was initially marked by regional clusters and VRE outbreaks in hospitals in South-Western Germany in 2004 and 2005, mainly caused by vanA-type VRE of ST203. Against the background of a certain "basic level" of VRE prevalence throughout Germany, an early shift from the vanA genotype to the vanB genotype in clinical isolates already occurred at the end of the 2000s without much notice. With the beginning of the third decade in 2010, VRE rates in Germany have permanently increased, first in some federal states and soon after country-wide. Besides an increase in VRE prevalence, this decade was marked by a sharp increase in vanB-type resistance and a dominance of a few, novel strain variants like ST192 and later on ST117 (CT71, CT469) and ST80 (CT1065). The largest VRE outbreak, which involved about 2,900 patients and lasted over three years, was caused by a novel and until that time, unknown strain type of ST80/CT1013 (vanB). Across all periods, VRE outbreaks were mainly oligoclonal and strain types varied over space (hospital wards) and time. The spread of VRE strains obviously respects political borders; for instance, both vancomycin-variable enterococci which were highly prevalent in Denmark and ST796 VRE which successfully disseminated in Australia and Switzerland, were still completely absent among German hospital patients, until to date.

Enterococcus faecium NCIMB10415 responds to norepinephrine by altering protein profiles and phenotypic characters

The long-term established symbiosis between gut microbiota and humans is based upon a dynamic equilibrium that, if unbalanced, could lead to the development of diseases. Despite the huge amount of data concerning the microbiota-gut-brain-axis, little information is available on what happens at the molecular level in bacteria, when exposed to human signals. In the present study, the physiological effects exerted by norepinephrine (NE), a human hormone present in significant amounts in the host gut, were analyzed using the commensal/probiotic strain Enterococcus faecium NCIMB10415 as a target. The aim was to compare the protein profiles of treated and untreated bacteria and relating these proteome patterns to some phenotypic modifications important for bacteria-host interaction. Actually, to date, only pathogens have been considered. Combining a gel-free/label-free proteomic analysis with the evaluation of bile salts resistance, biofilm formation and autoaggregation ability (as well as with the bacterial growth kinetics), allowed to detect changes induced by NE treatment on all the tested probiotic properties. Furthermore, exposure to the bioactive molecule increased the abundance of proteins related to stress response and to host-microbe interaction, such as moonlight proteins involved in adhesion and immune stimulation. The results of this investigation demonstrated that, not only pathogens, but also commensal gut bacteria are affected by host-derived hormones, underlining the importance of a correct cross-signalling in the maintenance of gut homeostasis. SIGNIFICANCE: The crucial role played by the human gut microbiota in ensuring host homeostasis and health is definitively ascertained as suggested by the holobiome concept. The present research was intended to shed light on the endocrinological perturbations possibly affecting microbiota. The microbial model used in this study belongs to Enterococcus faecium species, whose controversial role as gut commensal and opportunistic pathogen in the gut ecosystem is well recognized. The results obtained in the present investigation clearly demonstrate that E. faecium NCIMB10415 can sense and respond to norepinephrine, a human hormone abundant at the gut level, by changing protein profiles and physiology, inducing changes that could favor survival and colonization of the host tissues. To our knowledge, this is the first proteomic report concerning the impact of a human hormone on a commensal/probiotic bacterium, since previous research has focused on exploring the effects of neuroendocrine molecules on growth and virulence of pathogenic species.

Nematode-Associated Bacteria: Production of Antimicrobial Agent as a Presumptive Nominee for Curing Endodontic Infections Caused by Enterococcus faecalis

Xenorhabdus and/or Photorhabdus bacteria produce antibacterial metabolites to protect insect cadavers against food competitors allowing them to survive in nature with their nematode host. The effects of culture supernatant produced by Xenorhabdus and Photorhabdus spp. were investigated against the multidrug-resistant dental root canal pathogen Enterococcus faecalis. The efficacy of seven different cell-free supernatants of Xenorhabdus and Photorhabdus species against E. faecalis was assessed with overlay bioassay and serial dilution techniques. Additionally, time-dependent inactivation of supernatant was evaluated. Among the seven different bacterial species, X. cabanillasii produced the strongest antibacterial effects. Loss of bioactivity in a phosphopantetheinyl transferase-deficient mutant of X. cabanillasii indicated that this activity is likely based on non-ribosomal peptide synthetases (NRPSs) or polyketide synthases (PKSs). Subsequent in silico analysis revealed multiple possible biosynthetic gene clusters (BGCs) in the genome of X. cabanillasii including a BGC homologous to that of zeamine/fabclavine biosynthesis. Fabclavines are NRPS-derived hexapeptides, which are connected by PKS-derived malonate units to an unusual polyamine, also PKS-derived. Due to the known broad-spectrum bioactivity of the fabclavines, we generated a promoter exchange mutant in front of the fabclavine-like BGC. This leads to over-expression by induction or a knock-out by non-induction which resulted in a bioactive and non-bioactive mutant. Furthermore, MS and MS² experiments confirmed that X. cabanillasii produces the same derivatives as X. budapestensis. The medicament potential of 10-fold concentrated supernatant of induced fcl promoter exchanged X. cabanillasii was also assessed in dental root canals. Calcium hydroxide paste, or chlorhexidine gel, or fabclavine-rich supernatant was applied to root canals. Fabclavine-rich supernatant exhibited the highest inactivation efficacy of ≥3 log₁₀ steps CFU reduction, followed by calcium hydroxide paste (≤2 log₁₀ step). The mean percentage of E. faecalis-free dental root canals after treatment was 63.6, 45.5, and 18.2% for fabclavine, calcium hydroxide, and chlorhexidine, respectively. Fabclavine in liquid form or preferably as a paste or gel formulation is a promising alternative intracanal medicament.

Novel Small-molecule Antibacterials against Gram-positive Pathogens of Staphylococcus and Enterococcus Species

Defeat of the antibiotic resistance of pathogenic bacteria is one great challenge today and for the future. In the last century many classes of effective antibacterials have been developed, so that upcoming resistances could be met with novel drugs of various compound classes. Meanwhile, there is a certain lack of research of the pharmaceutical companies, and thus there are missing developments of novel antibiotics. Gram-positive bacteria are the most important cause of clinical infections. The number of novel antibacterials in clinical trials is strongly restricted. There is an urgent need to find novel antibacterials. We used synthetic chemistry to build completely novel hybrid molecules of substituted indoles and benzothiophene. In a simple one-pot reaction, two novel types of thienocarbazoles were yielded. Both indole substituted compound classes have been evaluated as completely novel antibacterials against the Staphylococcus and Enterococcus species. The evaluated partly promising activities depend on the indole substituent type. First lead compounds have been evaluated within in vivo studies. They confirmed the in vitro results for the new classes of small-molecule antibacterials.

Management of febrile neutropenia in the perspective of antimicrobial de-escalation and discontinuation

Introduction: Infections are among the most frequent complications in patients with hematological and oncological diseases. They might be classified as fever of unknown origin and microbiologically or clinically documented infections. Optimal duration of antimicrobial treatment is still unclear in these patients.Areas covered: We provide an overview on the management of febrile neutropenia in the perspective of antimicrobial de-escalation and discontinuation.Expert opinion: Patients with febrile high-risk neutropenia should be treated empirically with an anti-pseudomonal agent such as piperacillin/tazobactam. Several clinical studies support the assumption that the primary antibiotic regimen might be safely discontinued prior to neutrophil reconstitution if the patient is afebrile for several days and all infection-related symptoms have been resolved. Primary empirical treatment with carbapenems or antibiotic combinations should commonly only be considered in selected patient subgroups, such as patients with severe neutropenic sepsis or colonization with multidrug-resistant bacteria. Preemptive antifungal treatment guided by lung imaging and other parameters (e.g. serial Aspergillus galactomannan antigen screening) might reduce the consumption of antifungals compared to the classical empirical approach.Multidrug-resistant pathogens are emerging, and novel anti-infective agents under development are scarce. Therefore, a rational use of antimicrobials based on the principles of antibiotic stewardship is crucial.

Central venous catheter repair is highly successful in children with intestinal failure

PURPOSE

Damaged central venous catheters (CVCs) are commonly repaired to avoid line replacement and preserve vascular access. However, limited data suggest an increased risk for central line-associated bloodstream infections (CLABSIs) associated with the repair procedure. The purpose of this study was to describe outcomes of CVC repairs among parenteral nutrition (PN) dependent children with intestinal failure (IF).

METHODS

A 2-year retrospective review was performed on children with IF on home PN > 6 months. Outcomes of interest were repair success and postrepair CLABSI incidence. Descriptive statistics included medians and frequencies.

RESULTS

A total of 36 pediatric IF patients underwent 96 CVC repairs during the study period. The median CVC repair count was 1.5 repairs/patient (range, 1 to 16 repairs/patient) with >1 repair in half the patients. Ninety-four broken catheters (98%) were successfully repaired with restoration of function. Of the unsuccessful repairs (2%), the two catheters eventually required surgical removal and replacement. One repair (1%) was followed by a CLABSI with Enterococcus faecalis in an immunocompromised patient.

CONCLUSION

CVC repair is a highly successful procedure with a low risk for infection. Catheter repair should be considered whenever possible as it may extend the lifetime of the catheter and decrease the risk for vascular access loss.

LEVEL OF EVIDENCE

Treatment study; level IV.

Outbreaks caused by vancomycin-resistant Enterococcus faecium in hematology and oncology departments: A systematic review

Background

Vancomycin-resistance in Enterococcus faecium (VRE) poses a major threat in health care settings. It is well known that patients in hematology and oncology departments are especially at risk of nosocomial VRE acquisition. This systematic review of the literature provides data on the main sources, transmission modes and potential risk factors for VRE acquisition as well as appropriate infection control measures in order to terminate such nosocomial outbreaks.

Methods

Data on nosocomial VRE outbreaks on hematology and oncology wards was retrieved from the Outbreak Database and PubMed.

Results

A total of 35 VRE outbreaks describing 757 affected patients and 77 deaths were included in this review. The most frequent site of pathogen detection were stool samples or rectal swabs (57% of all isolation sites), followed by blood cultures (30%). The most common outbreak source was an index patient. The main modes of transmission were 1) hands of health care workers, 2) contact to a contaminated environment and 3) patient-to-patient contact. The most common risk factor for VRE positivity was prior antibiotic treatment. The most common infection control measures performed were screening and isolating or cohorting of patients.

Conclusion

A rational use of antibiotics in hematology and oncology units is recommended in order to reduce selection pressure on resistant pathogens such as VRE. In addition the importance of hand hygiene should be stressed to all staff whenever possible.

Novel Effective Small-Molecule Antibacterials against Enterococcus Strains

Enterococcus species cause increasing numbers of infections in hospitals. They contribute to the increasing mortality rates, mostly in patients with comorbidities, who suffer from severe diseases. Enterococcus resistances against most antibiotics have been described, including novel antibiotics. Therefore, there is an ongoing demand for novel types of antibiotics that may overcome bacterial resistances. We discovered a novel class of antibiotics resulting from a simple one-pot reaction of indole and o-phthaldialdehyde. Differently substituted indolyl benzocarbazoles were yielded. Both the indole substitution and the positioning at the molecular scaffold influence the antibacterial activity towards the various strains of Enterococcus species with the highest relevance to nosocomial infections. Structure-activity relationships are discussed, and the first lead compounds were identified as also being effective in the case of a vancomycin resistance.

Where is the difference between an epidemic and a high endemic level with respect to nosocomial infection control measures? An analysis based on the example of vancomycin-resistant Enterococcus faecium in hematology and oncology departments

Some infection control recommendations distinguish epidemic and endemic levels for infection control. However, it is often difficult to separate long lasting outbreaks from high endemic levels and it remains open, if this distinction is really useful. Aim: To compare infection control measures in endemic and epidemic outbreaks. Methods: The example of vancomycin-resistant Enterococcus faecium outbreaks in haematology or oncology departments was used to analyse differences in infection control measures between outbreaks and high endemic levels. The outbreak database and PubMed, including long lasting outbreaks, were used for this analysis. Two time limits were used for separation: 6 and 12 months. In addition, monoclonal and polyclonal outbreaks were distinguished. Findings: A total of 36 outbreaks were included. 13 outbreaks lasted 6 months or less, 9 outbreaks more than 6 months but at maximum 12 months and 9 more than 12 months. For the remaining outbreaks, no information about their duration was available. Altogether, 11 outbreaks were monoclonal and 20 polyclonal. Considering infection control measures, there were almost no differences between the different groups compared. Patient screening was given up in 37.5% of long lasting outbreaks (>12 months) and hand hygiene not reported in the majority of polyclonal outbreaks (77.8%). Conclusion: Despite many institutions trying to add further infection control measures in case of an outbreak, evidence based infection control measures should be implemented in endemic and epidemic situations. The crucial aspect is probably the degree of implementation and its control in both situations.

Weekly screening supports terminating nosocomial transmissions of vancomycin-resistant enterococci on an oncologic ward - a retrospective analysis

Background

To investigate the impact of weekly screening within the bundle of infection control measures to terminate vancomycin-resistant enterococci (VRE) transmissions on an oncologic ward.

Methods

A cluster of 12 VRE colonisation and five infections was detected on an oncologic ward between January and April 2015. Subsequently, the VRE point prevalence was detected and, as part of a the bundle of infection control strategies to terminate the VRE cluster, we isolated affected patients, performed hand hygiene training among staff on ward, increased observations by infection control specialists, intensified surface disinfection, used personal protective equipment and initiated an admission screening in May 2015. After a further nosocomial VRE infection in August 2015, a weekly screening strategy of all oncology patients on the respective ward was established while admission screening was continued. Whole genome sequencing (WGS)-based typing was applied to determine the clonal relationship of isolated strains.

Results

Initially, 12 of 29 patients were VRE colonised; of these 10 were hospital-acquired. During May to August, on average 7 of 40 patients were detected to be VRE colonised per week during the admission screening, showing no significant decline compared to the initial situation. WGS-based typing revealed five different clusters of which three were due to vanB- and two vanA-positive enterococci. After an additional weekly screening was established, the number of colonised patients significantly declined to 1/53 and no further nosocomial cases were detected.

Conclusions

Weekly screening helped to differentiate between nosocomial and community-acquired VRE cases resulting in earlier infection control strategies on epidemic situations for a successful termination of nosocomial VRE transmissions.

Fecal microbial transplantation as a therapeutic option in patients colonized with antibiotic resistant organisms

Despite increasing interest in fecal microbiota transplantation (FMT), its full therapeutic potential has yet to be determined. Since its increase in popularity, FMT has been shown to be highly effective in the treatment of both Clostridium difficile infection (CDI) and its recurrent form. Interest in FMT now expands well beyond the treatment of CDI to other processes with known associations to the microbiota such as antibiotic resistant infections, inflammatory bowel disease (IBD), hepatic encephalopathy, neuropsychiatric disorders, and metabolic disease. The rampant use and misuse of antibiotics in both medicine and agriculture has resulted in an increase in antibiotic resistant organisms which pose a significant risk to human health. The purpose of this commentary is to address the general issue of antibiotic resistance in the human microbiota and the restorative potential of FMT in this area.

Fecal microbiota transplantation for the intestinal decolonization of extensively antimicrobial-resistant opportunistic pathogens: a review

Treatment options for multidrug-resistant (MDR) bacterial infections are limited and often less effective. Non-pharmacologic approaches to preventing or treating MDR infections are currently restricted to improved antimicrobial stewardship and infection control practices. Fecal microbiota transplantation (FMT), a highly effective treatment for recurrent Clostridium difficile infection, has emerged as a promising therapy for intestinal MDR bacterial decolonization. A total of eight case reports have been published showing FMT resulted in intestinal decolonization of extended spectrum β-lactamase (ESBL)-producing and carbapenemase-producing Enterobacteriaceae, vancomycin-resistant Enterococci, or methicillin-resistant Staphylococcus aureus. The procedure has been shown to work even in immunocompromised patients and those experiencing medical crises without any adverse events. Five trials are currently underway to further investigate the use of FMT for MDR bacterial decolonization. FMT is a completely novel way to eradicate drug-resistant bacteria from the intestinal reservoir and should be further investigated to address the global problem of difficult-to-treat, MDR bacterial infections.

Reconsidering Contact Precautions for Endemic Methicillin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococcus

BACKGROUND

Whether contact precautions (CP) are required to control the endemic transmission of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in acute care hospitals is controversial in light of improvements in hand hygiene, MRSA decolonization, environmental cleaning and disinfection, fomite elimination, and chlorhexidine bathing.

OBJECTIVE

To provide a framework for decision making around use of CP for endemic MRSA and VRE based on a summary of evidence related to use of CP, including impact on patients and patient care processes, and current practices in use of CP for MRSA and VRE in US hospitals.

DESIGN

A literature review, a survey of Society for Healthcare Epidemiology of America Research Network members on use of CP, and a detailed examination of the experience of a convenience sample of hospitals not using CP for MRSA or VRE.

PARTICIPANTS

Hospital epidemiologists and infection prevention experts.

RESULTS

No high quality data support or reject use of CP for endemic MRSA or VRE. Our survey found more than 90% of responding hospitals currently use CP for MRSA and VRE, but approximately 60% are interested in using CP in a different manner. More than 30 US hospitals do not use CP for control of endemic MRSA or VRE.

CONCLUSIONS

Higher quality research on the benefits and harms of CP in the control of endemic MRSA and VRE is needed. Until more definitive data are available, the use of CP for endemic MRSA or VRE in acute care hospitals should be guided by local needs and resources.

Infect Control Hosp Epidemiol 2015;36(10):1163–1172

New insights into the antimicrobial effect of mast cells against Enterococcus faecalis

Enterococcus faecalis has emerged as an important cause of life-threatening multidrug-resistant bacterial infections in the hospital setting. The pathogenesis of enterococcal infections has remained a relatively neglected field despite their obvious clinical relevance. The objective of this study was to characterize the interactions between mast cells (MCs), an innate immune cell population abundant in the intestinal lamina propria, and E. faecalis. This study was conducted with primary bone marrow-derived murine MCs. The results demonstrated that MCs exerted an antimicrobial effect against E. faecalis that was mediated both by degranulation, with the concomitant discharge of the antimicrobial effectors contained in the granules, and by the release of extracellular traps, in which E. faecalis was snared and killed. In particular, the cathelicidin LL-37 released by the MCs had potent antimicrobial effect against E. faecalis. We also investigated the specific receptors involved in the recognition of E. faecalis by MCs. We found that Toll-like receptors (TLRs) are critically involved in the MC recognition of E. faecalis, since MCs deficient in the expression of MyD88, an adaptor molecule required for signaling by most TLRs, were significantly impaired in their capacity to degranulate, to reduce E. faecalis growth as well as to release tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) after encountering this pathogen. Furthermore, TLR2 was identified as the most prominent TLR involved in the recognition of E. faecalis by MCs. The results of this study indicate that MCs may be important contributors to the host innate immune defenses against E. faecalis.

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.

Outbreak of vancomycin-resistant enterococci in a tertiary hospital: the lack of effect of measures directed mainly by surveillance cultures and differences in response between Enterococcus faecium and Enterococcus faecalis

To describe the effect of active surveillance to control vancomycin-resistant enterococci (VRE) after an outbreak, 549 surveillance rectal cultures were performed in 308 patients (35% positive). An educational intervention to prevent transmission was implemented. Infection and colonization by VR- Enterococcus faecalis decreased, but Enterococcus faecium persisted despite control measures. Infections by VR-E faecalis fell to zero in 2008. We observed difficulties in controlling colonization with measures directed mainly by surveillance cultures and differences between responses of E faecium and E faecalis.

Molecular epidemiology of vancomycin-resistant Enterococcus faecium strains isolated from haematological malignancy patients in a research hospital in Turkey

Infections and outbreaks of vancomycin-resistant enterococci (VRE) still appear to be rare in Turkey. In the present study, VRE strains isolated during an outbreak in a haematology unit of a training and research hospital in Turkey were typed and their antimicrobial-resistance patterns were characterized by molecular methods. Twelve vancomycin-resistant Enterococcus faecium strains isolated from patients with haematological malignancies were investigated by PCR for the presence of genes encoding resistance to vancomycin, tetracycline, chloramphenicol, gentamicin and erythromycin. Their clonal relationship was evaluated by PFGE and multilocus sequence typing. All strains were resistant to vancomycin and erythromycin, and had the vanA and ermB genes, respectively. PFGE was used to determine the presence of two pulsotypes and determine their subtypes. Pulsotype A belonged to sequence type (ST) 17 and pulsotype B belonged to ST 78. All strains with the vanA gene were not the same clone, indicating multiple acquisitions of resistant isolates, even over such a short time period.

Screening and isolation for infection control

Control measures aimed to reduce the prevalence of healthcare-associated infections include active surveillance cultures (ASCs), contact isolation of patients colonised with epidemiologically significant pathogens, and pre-emptive isolation of high risk patients. However, the benefits of these measures are questionable. A systematic review of isolation policies demonstrated that intensive concerted interventions including isolation can substantially reduce nosocomial meticillin-resistant Staphylococcus aureus (MRSA) infection. Monitoring of interventions is fundamental. Surveillance data should be presented and fed back appropriately. International guidelines suggest that only intensive care units should apply extensive ASCs. However, legislation for mandatory screening at hospital admission has been advocated in many countries. Targeted screening could be used to limit the potential for dissemination of antibiotic-resistant pathogens from otherwise unsuspected carriers from the start of patients' hospitalisation, as opposed to other strategies, in which screening programmes target patients already hospitalised. Although the influx of antibiotic-resistant pathogens into the hospital would not change, early detection would reduce the time colonised patients might have to disseminate pathogens. Recently, rapid methods for molecular detection of MRSA have been developed. Data on the impact of these tests on the MRSA acquisition rate are extremely heterogeneous. Published studies differ according to the settings in which they have been evaluated, the choice of patient population to be screened, other infection control measures employed and, most importantly, study design and baseline prevalence of MRSA. Based on these studies, definitive recommendations cannot be made.

Outbreak of vancomycin-resistant enterococcus colonization among pediatric oncology patients

OBJECTIVE

To detect the burden of vancomycin-resistant Enterococcus (VRE) colonization among pediatric oncology patients and to determine risk factors for VRE acquisition.

DESIGN

Retrospective case-control study.

SETTING

The Children's Hospital of Philadelphia.

PATIENTS

Pediatric oncology patients hospitalized from June 2006 through December 2007.

METHODS

Prevalence surveys revealed an increased VRE burden among pediatric oncology patients. For the case-control study, the 16 case patients were pediatric oncology patients who had 1 stool sample negative for VRE at screening before having a stool sample positive for VRE at screening; the 62 control patients had 2 consecutive screenings in which stool samples were negative for VRE. Case and control patients were matched on the duration of the interval between screens. Analyses were performed to determine the association between multiple exposures and VRE acquisition.

RESULTS

The prevalence survey revealed that 5 (9.6%) of 52 patients had unsuspected VRE colonization at the time of hospitalization. Multivariate analysis identified a lack of empirical contact precautions (odds ratio [OR], 17.16 [95% confidence interval {CI}, 1.49-198.21]; P= .02) and the presence of a gastrointestinal device (OR, 4.03 [95% CI, 1.04-15.56]; P= .04) as significant risk factors for acquisition of VRE. Observations in the interventional radiology department revealed that staff could not access the portions of the electronic medical record in which isolation precautions were documented. Simple interventions that granted access and that trained interventional radiology staff to review the need for precautions, coupled with enhanced infection control practices, interrupted ongoing transmission and reduced the proportion of VRE screens that were positive to 15 (1.2%) of 1,270.

CONCLUSIONS

Inadequate communication with regard to infection control precautions can increase the risk of transmission of epidemiologically important organisms, particularly when patients receive care at multiple clinic locations. Adherence to infection control practices across the spectrum of care may limit the spread of resistant organisms.