Does vancomycin prescribing intervention affect vancomycin-resistant enterococcus infection and colonization in hospitals? A systematic review

Prevalence of vancomycin-resistant enterococcus in Africa in one health approach: a systematic review and meta-analysis

Vancomycin-resistant enterococci are a global challenge currently as reported by the World Health Organization. It is also important to recognize that combating antimicrobial resistance needs to recognize the interconnections between people, animals, plants and their shared environment in creating public health, the so-called One Health approach. Although the presence of VRE has been described in many regions of the world, there is a lack of comprehensive data indicating their prevalence of in Africa. Therefore, this study aimed to aggregate the result of studies describing VRE reported across multiple regions in Africa. A literature search was conducted on PubMed, Google scholar, and Hinari with the term “Vancomycin resistance enterococcus in Africa” on August 1–3, 2019. All available articles were downloaded to “Endnote version 7.1” then to Microsoft Word 2013. Articles determined to meet our criteria for the review was extracted to Microsoft Excel 2013. Those articles that reported the prevalence of vancomycin resistance Enterococcus obtained from all sample types and published from 2010 to 2019 in the English language were included for the review. A meta-analysis was conducted with OpenMetaAnalyst version R.3.1.0 software. The effect size was determined using a binary random effect model and statically significant considered when p < 0.05. Heterogeneity determined with the inconsistency index. A leave one out analysis used to perform the sensitivity analysis. There were 151 articles identified from the database searches; of this, 36 articles included after extensive review with two independent authors. Out of 4073 samples collected, 1488 isolates identified with an overall pooled prevalence of VRE 26.8% (95% CI; 10.7–43.0%) in Africa with a one-health perspective. The analysis showed that considerable heterogeneity among the studies (I² = 99.97%; p < 0.001). Subgroup analysis in-country, African region, laboratory method, year of publication, and sample source showed that a high prevalence was identified from South Africa (74.8%), South African regions (74.8%), PCR (959.2%), 2010–2015 years (30.3%) and environmental (52.2%), respectively. This meta-analysis indicates that there was a high-pooled prevalence of vancomycin-resistant enterococci in African. A lot should be done to prevent and control the transmission of vancomycin resistance enterococci to a human being from the environment in the continent.

Global prevalence of antibiotic resistance in blood-isolated Enterococcus faecalis and Enterococcus faecium: a systematic review and meta-analysis

INTRODUCTION

One of the global concerns is the increasing trend toward antimicrobial resistance and the consequent lack of efficient antimicrobials. Nosocomial infections present a big threat for patients all over the world and treatment with broad-spectrum antibiotics leads to outgrowth of hospital-associated resistant Enterococci clones that are very important in bloodstream infections. We surveyed the frequency and time trend of antibiotic resistance in Enterococci blood isolates from hospitalized patients in different regions of the world.

METHODS

Literature from January 1, 2000 to May 20, 2018 was searched systematically using Medline (via PubMed), Embase, and Cochrane Library and all original publications on the antibiotic resistance prevalence in blood-isolated Enterococci strains with standard laboratory tests were included. Quality of the included studies was assessed with the modified Critical Appraisal Checklist recommended by the Joanna Briggs Institute. Depending on the heterogeneity test, we used either random or fixed effect models to assess the appropriateness of the pooled prevalence of drug resistance.

RESULTS

A total of 291 studies were enrolled in the meta-analysis. Between all antibiotics, based on the WHO original offices, American countries showed the lowest prevalence of resistance for linezolid in Enterococcus faecalis. Regarding the prevalence of vancomycin resistance, Western Pacific, European, and American countries had the lowest level of resistance and South-East Asia and Eastern Mediterranean countries showed the highest level of resistance. Moreover, our findings for Enterococcus faecium indicated that America and South-East Asia had the lowest and the highest levels of resistance for linezolid, respectively.

CONCLUSION

Based on our findings, the prevalence of vancomycin-resistant E. faecium in bloodstream infections is significantly high, especially in Eastern Mediterranean countries, which is a massive warning signal for resistance to this broad-spectrum antibiotic. Therefore, the establishment of appropriate antibiotic usage guidelines should be essential in these countries.

Bloodstream infections with vancomycin-resistant enterococci are associated with a decreased survival in patients with hematological diseases

Enterococcus species are commensals of the human gastrointestinal tract with the ability to cause invasive infections. For patients with hematological diseases, enterococcal bloodstream infections (BSI) constitute a serious clinical complication which may even be aggravated if the pathogen is vancomycin-resistant. Therefore, we analyzed the course of BSI due to vancomycin-susceptible enterococci (VSE) in comparison to vancomycin-resistant enterococci (VRE) on patient survival. In this retrospective single-center study, BSI were caused by VRE in 47 patients and by VSE in 43 patients. Baseline patient characteristics were similar in both groups. Concerning infection-related characteristics, an increased CRP value and an increased rate of prior colonization with multidrug-resistant organisms were detected in the VRE BSI group. More enterococcal invasive infections were found in the VSE group. The primary endpoint, overall survival (OS) at 30 days after BSI, was significantly lower in patients with VRE BSI compared to patients with VSE BSI (74.5% vs. 90.7%, p = 0.039). In a multivariate regression analysis, VRE BSI and a Charlson comorbidity index higher than 4 were independent factors associated with 30-day mortality. Moreover, we found that VRE with an additional teicoplanin resistance showed a trend towards an even lower OS.

Characterization and anti-salmonella activities of lactic acid bacteria isolated from cattle faeces

Background

Non typhoidal salmonellosis is one of the neglected zoonoses in most African countries. The use of sub-therapeutic doses of antibiotics as animal growth promoter enhances the emergence and dissemination of antimicrobial resistance in bacteria with food animal reservoirs and may also results in antibiotics residue in animal products. One promising alternative to antibiotics in animal feed is Lactic Acid Bacteria (LAB) as probiotics. This study was carried out to determine the anti-salmonella activities and suitability of LAB isolated from cattle faeces in Nigeria as potential probiotics in cattle feed.

Method

The test Salmonella enterica spp strains and LAB were isolated from cattle faeces and identified by MALDI-TOF MS and partial sequencing of 16S rRNA genes respectively. The anti-salmonella activities of the isolated LAB in co-culture, cell-free supernatant, inhibition of growth by viable LAB cells and quantification of organic acids were determined by standard techniques. The ability of the LAB strains to withstand gastric conditions, antibiotic susceptibility and their haemolytic ability on blood agar were also determined.

Results

A total of 88 LAB belonging to 15 species were isolated and identified from cattle faeces. The most abundant species were Streptococcus infantarius (26), Enterococcus hirae (12), Lactobacillus amylovorus (10), Lactobacillus mucosae (10) and Lactobacillus ingluviei (9). Most of the LAB strains showed good anti-salmonella activities against the test Salmonella enterica spp. with 2 Lactobacillus strains; Lactobacillus amylovorus C94 and Lactobacillus salivarius C86 exhibiting remarkable anti-salmonella activities with total inhibition of Salmonella spp after 18 hours of co-incubation. The selected strains were able to survive simultaneous growth at pH 3 and 7% bile concentration and are non hemolytic.

Conclusion

This study reports the vast diversity of culturable LAB in cattle faeces from Nigeria and their putative in-vitro antibacterial activity against Salmonella enterica spp isolated from cattle. Lactobacillus amylovorus C94 and Lactobacillus salivarius C86 demonstrated promising probiotic potentials in-vitro and will be further tested in-vivo in animal field trial.

Patient Factors Associated With Methicillin-Resistant Staphylococcus aureus Septic Arthritis in Children

Staphylococcus aureus is the most common causative organism in pediatric septic arthritis, with methicillin-resistant Staphylococcus aureus (MRSA) being responsible for a significant portion of these infections. Early identification and initiation of proper treatment may improve outcomes by minimizing potential morbidity. The purpose of this study was to identify variables obtained on initial patient presentation associated with MRSA septic arthritis. Sixteen factors were retrospectively evaluated in 109 consecutive pediatric patients diagnosed with culture-confirmed septic arthritis. Graphical and logistical regression analyses were employed to determine factors independently predictive of MRSA septic arthritis. Twenty-seven (25%) patients had MRSA and 82 (75%) had non-MRSA septic arthritis. C-reactive protein of 13.7 mg/L or greater, duration of symptoms of 4 days or more, heart rate of 126 beats per minute or greater, and absolute neutrophil count of 8.72×10³ cells/µL or greater were associated with MRSA septic arthritis. Ultimately, 98% of patients with 1 or no risk factors had non-MRSA and 96% of patients with MRSA septic arthritis had 2 or more positive risk factors. Elevated C-reactive protein, duration of symptoms, heart rate, and absolute neutrophil count are predictive of MRSA infection in the setting of pediatric septic arthritis and can be obtained on initial evaluation. In patients for whom there is concern for MRSA infection, this may guide more expedient treatment, such as early initiation of contact precautions and appropriate antibiotic therapy before culture results become available. [Orthopedics. 2018; 41(2):e277-e282.].

Vancomycin-resistant enterococcus infection in the hematopoietic stem cell transplant recipient: an overview of epidemiology, management, and prevention

Vancomycin-resistant enterococcus (VRE) is now one of the leading causes of nosocomial infections in the United States. Hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of VRE colonization and infection. VRE has emerged as a major cause of bacteremia in this population, raising important clinical questions regarding the role and impact of VRE colonization and infection in HSCT outcomes as well as the optimal means of prevention and treatment. We review here the published literature and scientific advances addressing these thorny issues and provide a rational framework for their approach.

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.

Trends and relationship between antimicrobial resistance and antibiotic use in Xinjiang Uyghur Autonomous Region, China: Based on a 3 year surveillance data, 2014-2016

PURPOSES

The objective of the study was to identify the trends and relations between antimicrobial resistance (AMR) and antibiotic use in the Xinjiang Uyghur Autonomous Region in Western China from 2014 to 2016.

METHODS

A retrospective, descriptive analysis of AMR prevalence, and trends and relations between AMR and antibiotic use during the 3-year period was performed.

RESULTS

Third-generation cephalosporin-resistant Escherichia coli was the most prevalent resistant pathogen in terms of both resistance density and resistance proportion. A significant correlation was found between resistance density of third-generation cephalosporin-resistant Klebsiella pneumoniae and the use of beta-lactam-beta-lactamase inhibitor combinations (cc=0.63, p=0.03), quinolones (cc=0.60, p=0.04), and carbapenems (cc=0.76, p=0.004), among which only beta-lactam-beta-lactamase inhibitor combinations showed a significant correlation with third-generation cephalosporin-resistant E. coli (cc=0.63, p=0.03). For carbapenem-resistant Pseudomonas aeruginosa, not only carbapenem use (cc=0.65, p=0.02) but also penicillin (cc=0.76, p=0.004) and quinolone (cc=0.69, p=0.01) use showed significant correlation. A strong correlation was observed between the resistant proportion of third-generation cephalosporin-resistant E. coli and only the use of beta-lactam-beta-lactamase inhibitor combinations (cc=0.61, p=0.03).

CONCLUSION

The association between antibiotic use and AMR, especially the implication of the difference in resistance density and resistance proportion, is crucial for local physicians and decision-makers to better use of antibiotics and allocate healthcare resources more effectively, as well as to better implement antimicrobial stewardship and effective infection control strategies.

The effect of antibiotic use on prevalence of nosocomial vancomycin-resistant enterococci- an ecologic study

Background

Vancomycin-resistant enterococci (VRE) are among the most common antimicrobial-resistant pathogens causing nosocomial infections. Although antibiotic use has been identified as a risk factor for VRE, it remains unclear which antimicrobial agents particularly facilitate VRE selection. Here, we assessed whether use of specific antimicrobial agents is independently associated with healthcare-associated (HA) VRE rates in a university hospital setting in Berlin, Germany.

Methods

We conducted the study between January 2014 and December 2015 at the Charité-university hospital of Berlin, Germany. From the hospital pharmacy, we extracted data for all antibacterials for systemic use (anatomical therapeutic chemical (ATC)-classification J01) and calculated ward specific antibiotic consumption in defined daily doses (DDDs) per 100 patient-days (PD). We used the microbiology laboratory database to identify all patients with isolation of invasive or non-invasive VRE and calculated HA-VRE incidence as nosocomial VRE-cases per 100 patients and HA-VRE incidence density as nosocomial VRE-cases per 1000 PD. We defined VRE isolates as hospital-acquired if they were identified three days or later after hospital admission and otherwise as community-acquired (CA-VRE). We performed univariable and multivariable regression analyses to estimate the association of the frequency of HA-VRE per month with antibiotic use and other parameters such as length of stay, type of ward or presence of at least one CA-VRE on ward. In a second analysis, we considered only patients with VRE infections.

Results

We included data from 204,054 patients with 948,380 PD from 61 wards. Overall, 1430 VRE-cases were identified of which 409 (28.6%) were considered hospital-acquired (HA). We found that carbapenem use in the current month and prior-month use of glycopeptides increased the risk for HA-VRE by 1% per 1 DDD/100 PD and 3% per 1 DDD/100 PD, respectively. However, when only VRE from clinical samples were considered, only glycopeptide use showed a statistically significant association. In both models, detection of at least one patient with CA-VRE on a ward in the current month significantly increased the risk of HA-VRE, thereby indicating nosocomial spread of VRE.

Conclusions

Our findings suggest that the risk of HA-VRE is associated with specific antimicrobial agents. Prudent use of these antimicrobial agents might reduce nosocomial VRE rates. That appearance of at least one CA-VRE case on the ward increased the risk of HA-VRE detection highlights the importance of strict hand hygiene practices to interrupt person-to-person transmission of VRE.

Use of evidence-based recommendations in an antibiotic care bundle for the intensive care unit

PURPOSE

To drive decisions on antibiotic therapy in the intensive care unit (ICU), we developed an antibiotic care bundle (ABC-Bundle) with evidence-based recommendations (EBRs) for antibiotic prescriptions.

METHODS

We conducted a three-step prospective study. First, a systematic review was performed of the literature reporting EBRs for antibiotic usage in the ICU. Second, we developed an ABC-Bundle through a two-round, RAND-modified Delphi method with an international expert panel, including the most relevant EBRs on a 9-point Likert scale. Those EBRs that were considered mandatory by >50% of the experts were included in the bundle. Third, we assessed the adherence to and applicability of the bundle in two mixed university ICUs.

RESULTS

Out of 1190 potentially relevant articles, 14 (four guidelines, four randomised controlled trials and six systematic reviews) fulfilled the eligibility criteria. Six EBRs were classified as relevant: 1. Provide rationale for antibiotic start; 2. Perform appropriate microbiological sampling; 3. Prescribe empirical antibiotic therapy according to guidelines (Day 1); 4. Review diagnosis; 5. Evaluate de-escalation based on microbiological results (Days 2-5); and 6. Consider discontinuation of treatment (Days 3-5). Daily adherence to the ABC-Bundle, prospectively assessed in 861 days of therapy in 142 ICU patients, ranged from 2% to 37%.

CONCLUSION

The ABC-Bundle is a novel tool to improve delivery of appropriate antibiotic therapy to ICU patients. The low adherence in the prospective cohorts confirms the significant role that the ABC-Bundle could play in an antibiotic stewardship programme in the ICU setting.

Vancomycin-Resistant Enterococci: Epidemiology, Infection Prevention, and Control

Vancomycin-resistant enterococci (VRE) infections have acquired prominence as a leading cause of health care-associated infections. Understanding VRE epidemiology, transmission modes in health care settings, risk factors for colonization, and infection is essential to prevention and control of VRE infections. Infection control strategies are pivotal in management of VRE infections and should be based on patient characteristics, hospital needs, and available resources. Hand hygiene is basic to decrease acquisition of VRE. The effectiveness of surveillance and contact precautions is variable and controversial in endemic settings, but important during VRE outbreak investigations and control. Environmental cleaning, chlorhexidine bathing, and antimicrobial stewardship are vital in VRE prevention and control.

Non-linear significant relationship between use of glycopeptides and isolation of vancomycin-resistant Enterococcus species in a university hospital setting

BACKGROUND

Emergence of colonization and infection with vancomycin-resistant enterococci (VRE) has become a worldwide challenge. To investigate whether the increasing incidence of VRE isolation can be correlated with use of glycopeptides in the hospital setting, we conducted a hospital-wide two-year study in the university hospital of Vienna.

METHODS

Within the period from January 2011 through December 2012 all patients with isolation of invasive or non-invasive VRE were retrospectively included. Specialty-specific data concerning the consumption of vancomycin and teicoplanin, fluoroquinolones and third generation cephalosporins in defined daily doses (DDDs) from June 2010 through May 2012 were extracted from the hospital pharmacy computer system. To assess the relationship between the usage of those antibiotics and the incidence of VRE (VRE-rate per 10 000 patients) a Poisson regression was performed.

FINDINGS

In the study period 266 patients were colonized or infected with VRE. Specialty-specific VRE isolation was as follows: general surgical units (44 patients), bone marrow transplant unit (35 patients), general medical units (33 patients), cardiothoracic surgery (27 patients), nephrology (26 patients), haematooncology (22 patients), gastroenterology (17 patients), urology (17 patients), and the infectious diseases unit (11 patients). Hospital-wide consumption of glycopeptides was higher for teicoplanin than for vancomycin (26 242 versus 8677 DDDs). Specialty-specific VRE incidence significantly increased with the use of glycopeptides, fluoroquinolones or third generation cephalosporins (p < 0.001). The results of the Poisson regression for vancomycin (p = 0.0018) and teicoplanin (p < 0.0001) separately were both highly significant. Spearman's correlation coefficient indicated a strong correlation between the two variables (rho = 0.8).

CONCLUSION

Overall usage of glycopeptides, fluoroquinolones or third generation cephalosporins contributed to the emergence of VRE in the hospital setting.

Vancomycin-Resistant Enterococcal Bacteremia Pharmacotherapy

Objective: To review the literature on the pharmacotherapy of bloodstream infections (BSI) caused by vancomycin-resistant enterococci (VRE). Data Sources: A MEDLINE literature search was performed for the period 1946 to May 2014 using the search terms Enterococcus, enterococci, vancomycin-resistant, VRE, bacteremia, and bloodstream infection. References were also identified from selected review articles. Study Selection and Data Extraction: English-language case series, cohort studies, and meta-analyses assessing the options in the pharmacotherapy of VRE BSIs in adult patients were evaluated. Data Synthesis: Studies were identified that utilized linezolid, quinupristin/dalfopristin (Q/D), and daptomycin. In all, 8 comparative retrospective cohort studies, 2 meta-analyses of daptomycin and linezolid, and 3 retrospective comparisons of linezolid and Q/D were included for review. Mortality associated with VRE BSIs was high across studies, and the ability to determine differences in outcomes between agents was confounded by the complex nature of the patients included. Two meta-analyses comparing daptomycin with linezolid for VRE BSIs found modest advantages for linezolid, but these conclusions may be hampered by heterogeneity within the included studies. Conclusions: VRE BSIs remain a difficult-to-treat clinical situation. Differences in toxicity between the agents used to treat it are clear, but therapeutic differences are more difficult to discern. Meta-analyses suggest that a moderate advantage for linezolid over daptomycin may exist, but problems with the nature of studies that they included make definitive conclusions difficult.

Vancomycin-resistant Enterococcus outbreak in a neonatal intensive care unit: epidemiology, molecular analysis and risk factors

BACKGROUND

Vancomycin-resistant Enterococcus faecium (VRE) may cause outbreaks in neonatal intensive care units (NICU). We describe a biphasic VRE outbreak and identify risk factors for VRE acquisition.

METHODS

After the occurrence of 2 cases of VRE infections in a 44-bed NICU, a bundle of interventions was implemented that included active surveillance cultures for VRE, enhanced infection control measures, and audits on antimicrobial use, from June to December 2008. Analysis was performed using polymerase chain reaction and pulse-field gel electrophoresis techniques. A case-control study was conducted to identify risk factors.

RESULTS

Among 253 neonates screened, 101 (39.9%) were found to be colonized with VRE. During the first 9 weeks of the study period, 59 new cases were detected. Molecular analysis showed 1 predominant clone. During weeks 10-12, no new cases of VRE colonization were detected; however, at week 13, just when the outbreak appeared to be over, a second wave occurred, with 42 new cases and multiple clones detected. Multivariate analysis identified administration of antimicrobial therapy for late-onset neonatal sepsis and hospitalization during the first month of this outbreak as significant risk factors for VRE colonization.

CONCLUSION

Both a high prevalence of VRE colonization and antimicrobial use promoted the transmission of VRE during this biphasic outbreak. Adherence to infection control measures and antimicrobial stewardship policies are of utmost importance.

Resolution of Clostridium difficile–Associated Diarrhea in Patients With Cancer Treated With Fidaxomicin or Vancomycin

Purpose

Patients with cancer are at increased risk for Clostridium difficile–associated diarrhea (CDAD). Little is known about treatment response.

Patients and Methods

Two double-blind trials randomly allocated 1,105 patients with CDAD to fidaxomicin or vancomycin treatment (modified intent-to-treat [mITT]), and 183 of these had cancer. Univariate and multivariate post hoc analyses compared effects of treatment and patient characteristics on cure, recurrence, and sustained response after 4 weeks. Time to resolution of diarrhea (TTROD) was also evaluated.

Results

Patients with cancer had a lower cure rate and longer TTROD than patients without cancer. Recurrence rates were similar. Cure was more likely with fidaxomicin than vancomycin (odds ratio [OR] 2.0; P = .065), recurrence was less likely (OR = 0.37; P = .018), and sustained response more frequent (OR = 2.56; P = .003). Under vancomycin, median TTROD was longer in patients with cancer than in those without (123 v 58 hours; log-rank P < .001). With fidaxomicin, median TTROD was not significantly affected by presence of cancer (74 v 54 hours; log-rank P = .145). In the full mITT population, age, hypoalbuminemia, and cancer were inversely associated with clinical cure by multivariate analysis. Study treatment with vancomycin was a significant predictor of recurrence (P < .001). Within the cancer population, low albumin was negatively and fidaxomicin was positively associated with improved cure.

Conclusion

For patients with cancer, fidaxomicin treatment was superior to vancomycin, resulting in higher cure and sustained response rates, shorter TTROD, and fewer recurrences.

Antimicrobial agent exposure and the emergence and spread of resistant microorganisms: issues associated with study design

Antibiotics are essential agents that have greatly reduced human mortality due to infectious diseases. Their use, and sometimes overuse, have increased over the past several decades in humans, veterinary medicine and agriculture. However, the emergence of resistant pathogens is becoming an increasing problem that could result in the re-emergence of infectious diseases. Antibiotic prescription in human medicine plays a key role in this phenomenon. Under selection pressure, resistance can emerge in the commensal flora of treated individuals and disseminate to others. However, even if the effects of antimicrobial use on resistance is intuitively accepted, scientific rationales are required to convince physicians, legislators and public opinion to adopt appropriate behaviours and policies. With this review, we aim to provide an overview of different epidemiological study designs that are used to study the relationship between antibiotic use and the emergence and spread of resistance, as well as highlight their main strengths and weaknesses.

Polyclonal outbreak of vancomycin-resistant Enterococcus faecium in a pediatric oncology department

We present a polyclonal outbreak of vancomycin-resistant enterococci (VRE) colonization in a pediatric oncology department and the role of a bundle of actions. After the occurrence of VRE bloodstream infections in 2 patients, an active surveillance of VRE colonization was started. Enhanced infection control measures and closure of the department to new admissions for the first 3 months were implemented. Among 32 patients screened for VRE, 21 were found colonized. Daily prevalence of VRE colonization among hospitalized patients ranged from 40% to 75%, but no new VRE infections occurred. Monthly incidence of VRE colonization decreased from 2.5 to 0.6 cases per 100 occupied bed-days at the end of this outbreak by the implementation of the above-mentioned measures. All VRE isolates tested were Enterococcus faecium carrying VanA gene. Pulsed field gel electrophoresis showed a polyclonal outbreak. A case-control study did not show any particular risk factors for colonization. High use of glycopeptide was noted before study outbreak that was drastically decreased during the study but only temporarily. Control of VRE in pediatric oncology departments with high colonization rates is challenging and requires a multifaceted strategy. Polyclonal spread of VRE found in this study suggests a possible effect of prior antimicrobial overuse and the critical need for antimicrobial stewardship especially in the era of multidrug-resistant bacteria.

Enterococcal bacteremia is associated with increased risk of mortality in recipients of allogeneic hematopoietic stem cell transplantation

BACKGROUND

Enterococci are an important cause of healthcare-associated infections. We retrospectively analyzed risk factors and outcome of vancomycin-resistant enterococci (VRE) and vancomycin-sensitive enterococci (VSE) infections.

METHODS

Seven hundred fifty-two patients who received hematopoietic stem cell transplants from 2004 through 2008 at the University of Minnesota were included.

RESULTS

Ninety-three patients had enterococcal bloodstream infection (BSI) during the first year after transplant. Vancomycin resistance was observed in 66% and 31% of isolates in adults and children, respectively. Cumulative incidence of VRE and VSE bacteremia was 6.6% (95% confidence interval [CI], 4.8%-8.4%) and 5.7% (95% CI, 4.0%-7.4%), respectively. Colonization with VRE before or after transplant was a risk factor for VRE bacteremia (odds ratio [OR], 3.3 [95% CI, 1.3-8.3] and 7.0 [95% CI, 4.0-14.8], respectively). Delay in engraftment increased the incidence of VRE bacteremia from 4.5% (95% CI, 2.9-6.6) if engrafted before day 21 and to 15% (95% CI, 3.2%-38%) if engrafted between days 36 and 42. In adults, mortality 30 days after infection was 38% for both VRE (95% CI, 25%-54%) and VSE cases (95% CI, 21%-62%). The hazard ratio for all-cause mortality up to 1 year after transplant was 4.2 (95% CI, 3.1-6.9) and 2.7 (95% CI, 1.4-5.1) for patients with VRE and VSE BSIs, respectively, compared to patients without enterococcal BSI. In pediatric patients, mortality 30 days after VRE and VSE bacteremia was 20% (95% CI, 5.4%-59%) and 4.5% (95% CI, .6%-28%), respectively.

CONCLUSION

High rates of vancomycin resistance and association of enterococcal infections with significant mortality warrant further efforts to optimize prevention and management of these infections.

Bactericidal activity of soymilk fermentation broth by in vitro and animal models

Soybean fermentation broth (SFB) exhibits potent antibacterial activity against different species of bacteria in in vitro assays and animal models. Four isoflavone compounds-daidzin, genistin, genistein, and daidzein-of SFB were analyzed and quantified by high-performance liquid chromatography. In the in vitro test, daidzin and daidzein had more potent antibacterial activity than genistin. The minimum inhibition concentration values for these bacteria of SFB ranged from 1.25% to 5%, and the minimum bactericidal concentration values of strains ranged from 2.5% to 10%, depending on the species or strain. Vancomycin-resistant Entercoccus faecalis (VRE) strains were also tested for susceptibility to SFB in two species of animal model: the Sprague-Dawley rat and the BALB/c mouse. SFB-fed Sprague-Dawley rats showed excellent elimination efficiency against VRE, close to 99% compared with the phosphate-buffered saline-fed control group. In the BALB/c mouse model, SFB antibacterial activity was 65-80% against VRE compared with the control. In conclusion, SFB contains natural antibacterial substances such as daidzin, genistin, and daidzein that inhibit bacterial growth.

Association between vancomycin-resistant Enterococci bacteremia and ceftriaxone usage

OBJECTIVE

Vancomycin-resistant enterococci (VRE) have become a public health concern with implications for patient mortality and costs. Hospital antibiotic usage may impact VRE incidence, but the relationship is poorly understood. Animal investigations suggest that ceftriaxone may be associated with VRE proliferation. We measured antimicrobial usage and VRE bloodstream infection (VRE-BSI) incidence to test our hypothesis that increased ceftriaxone usage would be associated with a higher incidence of VRE-BSI.

DESIGN

Retrospective cohort study.

SETTING

University of Alabama at Birmingham Medical Center, a 900-bed urban tertiary care hospital.

PARTICIPANTS

All patients admitted during the study period contributed data.

METHODS

We conducted a retrospective analysis of antimicrobial usage and VRE-BSI from 2005 to 2008 (43 months). Antimicrobial usage was quantified as days of therapy (DOTs) per 1,000 patient-days. VRE-BSI incidence was calculated as cases per 1,000 patient-days. Negative binomial regression with adjustment for correlation between consecutive observations was used to measure the association between antimicrobial usage and VRE-BSI incidence at the hospital- and care-unit levels.

RESULTS

VRE-BSI incidence increased from 0.06 to 0.17 infections per 1,000 patient-days. Hospital VRE-BSI incidence was associated with prior-month ceftriaxone DOTs (incidence rate ratio, 1.38 per 10 DOTs; P = .005). After controlling for ceftriaxone, prior-month cephalosporin usage (class) was not predictive of VRE-BSI (P = .70). Similarly, prior-month usage of piperacillin-tazobactam, ceftazidime, cefepime, cefazolin, or vancomycin was not predictive of VRE-BSI when considered individually (P≥ .4 for all comparisons). The final model suggests that type of intensive care unit was related to VRE-BSI incidence.

CONCLUSIONS

Ceftriaxone usage in the prior month, but not cephalosporin (class) or vancomycin usage, was related to VRE-BSI incidence. These findings suggest that an antimicrobial stewardship program that limits ceftriaxone may reduce nosocomial VRE-BSI incidence.

Differentiating between methicillin-resistant and methicillin-sensitive Staphylococcus aureus osteomyelitis in children: an evidence-based clinical prediction algorithm

BACKGROUND

Although osteomyelitis was once commonly due to methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA)--which causes more virulent and invasive infections--has emerged as an increasingly important cause. Differentiating clinically between MRSA and MSSA can be challenging, but is necessary in order to promptly administer appropriate antibiotics and maintain vigilance against possible sequelae of MRSA osteomyelitis. The purpose of our study was to develop a clinical prediction algorithm to distinguish between MRSA and MSSA osteomyelitis in children.

METHODS

A retrospective review of 129 children presenting with culture-proven Staphylococcus aureus osteomyelitis between 2000 and 2009 was performed. The demographics, symptoms, vital signs, and laboratory test values in the MSSA group (n = 118) and the MRSA group (n = 11) were compared with use of univariate analysis. Multivariate logistic regression with backward stepwise selection was then used to identify independent multivariate predictors of MRSA osteomyelitis, and each of these predictors was subjected to receiver operating characteristic curve analysis to determine the optimal cutoff value. Finally, a prediction algorithm for differentiating between MRSA and MSSA osteomyelitis on the basis of these independent predictors was constructed.

RESULTS

Patients with MRSA osteomyelitis differed significantly from those with MSSA osteomyelitis with regard to non-weight-bearing status, antibiotic use at presentation, body temperature, hematocrit value, heart rate, white blood-cell count, platelet count, C-reactive protein level, and erythrocyte sedimentation rate. Four significant independent multivariate predictors were identified: a temperature of >38°C, a hematocrit value of <34%, a white blood-cell count of >12,000 cells/µL, and a C-reactive protein level of >13 mg/L. The predicted probability of MRSA osteomyelitis, determined on the basis of the number of these predictors that a child satisfied, was 92% for all four predictors, 45% for three, 10% for two, 1% for one, and 0% for zero predictors. Receiver operating characteristic curve analysis was used to evaluate the predictive accuracy of the number of multivariate predictors, and this analysis revealed a steep shoulder and an area under the curve of 0.94 (95% confidence interval, 0.88 to 1.00).

CONCLUSIONS

Our proposed set of four predictors provided excellent diagnostic performance in differentiating between MRSA and MSSA osteomyelitis in children, and thus would be able to guide patient management and facilitate timely antibiotic selection.

Risk factors for prolonged carriage of vancomycin-resistant Enterococcus faecium among patients in intensive care units: a case-control study

OBJECTIVES

The aim of this study was to identify the risk factors for prolonged carriage of vancomycin-resistant Enterococcus faecium (VREF) in intensive care units (ICUs).

METHODS

A retrospective case-control study was performed in the ICUs of a university hospital in Korea from September 2006 to July 2009. VREF carriage was identified through weekly active surveillance rectal cultures. Clinical characteristics and the risk factors for VREF acquisition were compared between cases with prolonged VREF carriage (≥ 5 weeks, n = 58) and controls with shorter VREF carriage (<3 weeks, n = 36) in a multivariate logistic regression model. The effect of vancomycin consumption on vancomycin-resistant enterococci (VRE) colonization pressure was investigated using time-series analysis with an autoregressive error model.

RESULTS

Out of a total of 6327 rectal swab cultures examined, 1915 (30.3%) specimens from 266 patients were positive for VREF. The weekly VRE colonization pressure ranged from 0.77% to 42.42%. Vancomycin use after VREF acquisition significantly increased VREF carriage (adjusted odds ratio = 4.09; 95% confidence interval = 1.32-12.65). The case group had higher in-hospital mortality than the control group [21 (36.2%) versus 4 (11.1%), P = 0.007]. Increment of VRE colonization pressure was significantly associated with vancomycin consumption of 1week before (i.e. time t - 1) (P = 0.0028) and moderately associated with that of the corresponding week (i.e. time t) (P = 0.0595).

CONCLUSIONS

Vancomycin use in patients with VREF colonization might prolong the duration of carriage. Restriction of vancomycin use should be strengthened in these patients through infection control measures.

Detection of human intestinal catalase-negative, Gram-positive cocci by rRNA-targeted reverse transcription-PCR

An analytical system based on rRNA-targeted reverse transcription-quantitative PCR (RT-qPCR) for enumeration of catalase-negative, Gram-positive cocci was established. Subgroup- or species-specific primer sets targeting 16S or 23S rRNA from Enterococcus, Streptococcus, and Lactococcus were newly developed. The RT-qPCR method using these primers together with the previously reported primer sets specific for the Enterococcus genus, the Streptococcus genus, and several Streptococcus species was found to be able to quantify the target populations with detection limits of 10(3) to 10(4) cells per gram feces, which was more than 100 times as sensitive as the qPCR method (10(6) to 10(8) cells per gram feces). The RT-qPCR analysis of fecal samples from 24 healthy adult volunteers using the genus-specific primer sets revealed that Enterococcus and Streptococcus were present as intestinal commensals at population levels of log(10) 6.2 +/- 1.4 and 7.5 +/- 0.9 per gram feces (mean +/- standard deviation [SD]), respectively. Detailed investigation using species- or subgroup-specific primer sets revealed that the volunteers harbored unique Enterococcus species, including the E. avium subgroup, the E. faecium subgroup, E. faecalis, the E. casseliflavus subgroup, and E. caccae, while the dominant human intestinal Streptococcus species was found to be S. salivarius. Various Lactococcus species, such as L. lactis subsp. lactis or L. lactis subsp. cremoris, L. garvieae, L. piscium, and L. plantarum, were also detected but at a lower population level (log(10) 4.6 +/- 1.2 per gram feces) and prevalence (33%). These results suggest that the RT-qPCR method enables the accurate and sensitive enumeration of human intestinal subdominant but still important populations, such as Gram-positive cocci.

Emerging antibiotic resistance in bacteria with special reference to India

The antibiotic era started in the 1940s and changed the profile of infectious diseases and human demography. The burgeoning classes and numbers promised much and elimination of this major cause of human (and animal) morbidity appeared possible. Bacterial antibiotic resistance which was observed soon after antibiotic introduction has been studied extensively. Diverse mechanisms have been demonstrated and the genetic basis elucidated. The resilience of the prokaryote ecosystems to antibiotic stress has been realized. The paper presents these subjects briefly to afford an overview. The epidemiology of antibiotic resistance is dealt with and community practices in different countries are described. The role of high antibiotic usage environments is indicated. The implication of the wide use of antibiotics in animals has been pointed out. Steadily increasing antibiotic resistance and decreasing numbers of newer antibiotics appear to point to a post-antibiotic period during which treatment of infections would become increasingly difficult. This article attempts to review the global antimicrobial resistance scene and juxtaposes it to the Indian experience. The prevalence in India of antibiotic resistance among major groups of pathogens is described. The factors that determine the prevalent high antibiotic resistance rates have been highlighted. The future research activity to ensure continued utility of antibiotics in the control of infections has been indicated.

Decision support systems for antibiotic prescribing

PURPOSE OF REVIEW

To explore recent developments in computerized evidence-based guidelines and decision support systems that have been designed to improve the effectiveness and efficiency of antibiotic prescribing.

RECENT FINDINGS

The most frequently utilized decision support systems are electronic guidelines and protocols, especially for empirical selection of antibiotics. The majority of decision support systems result in improvement in clinical performance and, in at least half of the published trials, in patient outcomes. Despite the reported successes of individual applications, the safety of electronic prescribing systems in routine practice has been identified recently as an issue of potential concern. Bioinformatics-assisted prescribing may contribute to reducing the complexities of prescribing combinations of antimicrobials in the era of multidrug resistance.

SUMMARY

The reemerging interest in prescribing decision support reflects the recent change in emphasis from support for diagnostic decisions towards support for patient management and from systems targeting a broad range of clinical diagnoses to task specific and condition-specific decision aids.

The dynamic relationship between antibiotic use and the incidence of vancomycin-resistant Enterococcus: time-series modelling of 7-year surveillance data in a tertiary-care hospital

The role of antibiotics in the epidemiology of vancomycin-resistant Enterococcus (VRE) has been studied extensively, but controversies remain as to which, and to what extent, antibiotics facilitate the emergence and dissemination of VRE in hospitals. Aggregate data on the use of several antibiotic classes in terms of defined daily doses (DDD) per 100 patient-days (PD), and VRE incidence rates in terms of clinical isolates per 1000 PD, were evaluated during a 7-year period at a tertiary-care hospital. Time-series analysis (autoregressive integrated moving average (ARIMA) and transfer function models) was used to quantify the temporal effect of antibiotic use on VRE incidence and estimate effect-delays. The incidence rate of VRE observed in a specific bimester was found to be a function of its value during the preceding bimester and of prior changes in the volume of use of four antibiotic classes. In particular, an increase of one DDD/100 PD in the use of glycopeptides, fluoroquinolones, extended-spectrum cephalosporins and beta-lactam-beta-lactamase inhibitor combinations resulted, independently, in average changes of +0.024, +0.015, + 0.020 and -0.010 isolates per 1000 PD in the incidence of VRE, with average delays of 2, 4, 2 and 6 months, respectively, which explained 56% of the observed variation in VRE rates over time. Efforts to reduce VRE cross-transmission should be supplemented by targeted antibiotic control policies. The use of glycopeptides, broad-spectrum cephalosporins and fluoroquinolones in high amounts should be the targets of such policies. Penicillin-beta-lactamase inhibitor combinations might be suitable substitutes for extended-spectrum cephalosporins.

Prevalence and significance of coagulase-negative staphylococci isolated from blood cultures in a tertiary hospital

Blood cultures (BC) are the most important tool in the diagnosis of bloodstream infections. However, false positive results are associated with increased laboratory costs and inappropriate antibiotic use. In order to determine the prevalence and location of blood cultures contaminated with coagulase-negative staphylococci (CNS), we performed a retrospective analysis of all blood cultures performed at St. Vincent's Hospital, Sydney during a 6-month period. From a total of 4234 patients with BC collected, CNS was isolated from 109 patients (2.6%). 94% of all CNS isolates (101/109) were contaminants. In the emergency department (ED), CNS isolates were significantly more likely to be contaminants (62/63, p<0.02) compared with the rest of the hospital, representing a 3.3% patient BC contamination rate. Treatment for a contaminant with vancomycin was significantly more likely to occur in ward patients (14/28, p<0.01) compared to the rest of the hospital. Duration of therapy did not differ across the hospital. Strategies to reduce the numbers of contaminants should be directed at medical staff in ED. Inappropriate vancomycin therapy could be curtailed by greater clinical microbiology liaison and vancomycin stewardship.

Empiric antibiotic therapy for acute osteoarticular infections with suspected methicillin-resistant Staphylococcus aureus or Kingella

The bacterial agents causing bone and joint infections have been changing. Currently, methicillin-resistant Staphylococcus aureus (MRSA) and Kingella kingae are emerging pathogens. For treatment of MRSA infections, clindamycin, vancomycin, and linezolid are commonly prescribed antibiotics. Kingella are sensitive to most penicillins and cephalosporins. Because MRSA osteoarticular infections tend to be severe, longer periods of antibiotic treatment with more frequent monitoring of inflammatory markers are sometimes required to obtain a complete cure with no residual complications. To assist management, we have included a clinical decision tree with antibiotic treatment protocols.