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

The intestinal carrier status of Enterococcus spp. in children: clonal diversity and alterations in resistance phenotypes before and after admission to a pediatric intensive care unit

BACKGROUND

This study aimed to investigate the intestinal carrier status of Enterococcus spp. among children in a pediatric intensive care unit (PICU) and reveal the role of hospitalization in the alteration of resistance phenotypes and clonal diversity of the isolates during admission and discharge periods.

METHODS

Two separate stool samples were collected from hospitalized patients in the pediatric intensive care unit at admission and discharge times. The culture was done, and Enterococcus species were tested for antimicrobial susceptibility and carriage of vanA-D gene subtypes. Random Amplified Polymorphic DNA (RAPD)-PCR was used for a phylogenetic study to check the homology of pairs of isolates.

RESULTS

The results showed carriage of Enterococci at admission, discharge, and at both time points in 31%, 28.7%, and 40.1% of the cases, respectively. High frequencies of the fecal Enterococcus isolates with vancomycin-resistance (VR, 32.6% and 41.9%), high-level of gentamicin-resistance (HLGR, 25.6% and 27.9%), and multi-drug resistance phenotypes (MDR, 48.8% and 65.1%) were detected at admission and discharge times, respectively. Resistance to vancomycin, ampicillin, and rifampicin was higher among E. faecium, but resistance to ciprofloxacin was higher in E. faecalis isolates. The increased length of hospital stay was correlated with the carriage of resistant strains to vancomycin, ampicillin, and ciprofloxacin. While the homology of the isolates was low among different patients during hospitalization, identical (9%) and similar (21%) RAPD-PCR patterns were detected between pairs of isolates from each patient.

CONCLUSIONS

The high rate of intestinal carriage of VR, HLGR-, and MDR-Enterococci at admission and during hospitalization in the PICU, and the impact of increased length of hospital stay on the fecal carriage of the resistant strains show the importance of antibiotic stewardship programs to control their transmission and spread in children.

Factors associated with vanA VRE acquisition in Cardiothoracic Surgery patients during an acute outbreak

BACKGROUND

There was an acute outbreak of vanA Enterococcus faecium (VREfm) in a tertiary Melbourne teaching hospital between 2015 and 2016 amongst Cardiothoracic Surgery (CTS) ward and Intensive Care Unit (ICU) patients. Prior to this outbreak vanB VRE had been the predominate genotype encountered.

METHODS

A retrospective, matched (1:2), case-control study was conducted on CTS patients between 1 August 2015 and 31 May 2016 admitted to a hospital in Melbourne, during an outbreak of vanA VREfm to identify factors associated with colonisation or infection. Factors assessed included undergoing surgery and type of procedure, exposure to antibiotics and admission to ICU.

RESULTS

During the outbreak, 56 new cases of vanA VREfm out of 802 CTS ward patients were identified. Of these new cases, 52 were included in the case-control analysis, all identified via rectal screening. Cases had significantly longer duration of stay in hospital (p < 0.001) than controls. Multivariable analysis identified exposure to ceftriaxone as an independent factor (OR 4.14, p = 0.018) associated with new vanA VREfm isolates. Other factors such as vancomycin exposure, specific CTS procedures or ICU admission were not identified as independent factors. Ceftriaxone was being used during the outbreak as surgical prophylaxis amongst CTS patients.

CONCLUSION

Ceftriaxone use was associated with an increased risk of CTS patients acquiring vanA VREfm during an acute outbreak. This highlights the overall importance of antibiotic stewardship to minimise hospital-associated multi-drug resistant infections.

Molecular detection of vanA and vanB genes among vancomycin-resistant enterococci in ICU-hospitalized patients in Ahvaz in southwest of Iran

Objective

Nosocomial infections due to vancomycin-resistant enterococci (VRE) are known as a source of spreading these bacteria. The aim of this prospective study was molecular detection of vanA and vanB genes among VRE isolated from patients admitted to intensive care units (ICUs) in Ahvaz in southwest of Iran.

Materials and methods

Overall, 243 non-duplicate rectal swab specimens were collected from ICU-hospitalized patients in teaching hospitals affiliated to Ahvaz Jundishapur University of Medical Sciences, Iran. The specimens were inoculated on suitable culture media, and isolates were identified by standard biochemical tests. The susceptibility and resistance of enterococci to 10 antibiotics were determined based on the Clinical and Laboratory Standards Institute guidelines. Resistance to vancomycin was phenotypically detected by vancomycin screening test, and the vanA and vanB genes in vancomycin-resistant isolates were amplified by multiplex PCR method.

Results

Of 175 specimens containing enterococci, 129 (73.7%) isolates were detected as Enterococcus faecium and Enterococcus faecalis and 46 (26.3%) isolates as Enterococcus spp. The results of susceptibility test showed high rates of resistance to tetracycline, erythromycin, ciprofloxacin, and ampicillin. Moreover, based on this test, out of 129 Enterococcus isolates, 56 (43.4%) were resistant to vancomycin and teicoplanin. Also, among 59 vancomycin-resistant or semi-susceptible isolates, vanA gene was detected in 54 (91.5%) isolates, while none of the isolates had vanB gene.

Conclusion

According to the results of this study, to prevent the spread of vancomycin-resistant Enterococcus strains, especially in nosocomial infections, the susceptibility of isolates should be determined before vancomycin prescription.

Prevalence of vancomycin resistance among isolates of enterococci in Iran: a systematic review and meta-analysis

Introduction

Enterococcus is responsible for 10% of hospital-acquired infections. The purpose of this review was to evaluate the prevalence of vancomycin-resistant Enterococcus (VRE) isolates in Iran using a meta-analysis method.

Materials and methods

Iranian databases, including Magiran and IranDoc, and international databases, including PubMed and MedLib, were examined carefully, and a total of 20 articles published between 2000 and 2011 were extracted. The data were subjected to meta-analysis and random-effects models. In addition, heterogeneous studies were assessed using the I ² index. Finally, the data were analyzed using R and STATA software.

Results

The results showed that the strain of Enterococcus faecalis had been more common than Enterococcus faecium in clinical infection (69% vs 28%). However, resistance to vancomycin was higher among strains of E. faecium compared with strains of E. faecalis (33% vs 3%). The complete resistance, intermediate resistance, and sensitivity to vancomycin among Enterococcus isolates were 14% (95% CI: 11, 18), 14% (95% CI: 5, 23), and 74% (95% CI: 65, 83), respectively. The resistance patterns, depending on the sample type, did not show a significant difference. In addition, the resistance of isolated strains to vancomycin in outpatients was significantly higher than that in inpatients (16% vs 1%). Moreover, 80%-86% of resistant strains were genotype van A and 14%-20% of resistant strains were genotype van B.

Conclusion

The findings of the present review show that there is a high frequency of resistant Enterococcus in Iran. Therefore, consideration of the prevalence and frequency of subjected resistant strains can be helpful for decision makers to implement proper health policies in this direction.

Rise of antibiotic resistance in clinical enterococcal isolates during 2001-2016 in Iran: a review

Introduction

The clinical significance of enterococci is mostly related to its antibiotic resistance which contributes to colonization and infection, in particular amongst the hospitalized patients. The present review has examined the literature to provide a comprehensive data on enterococci antibiotic resistance during the last 20 years in Iran.

Methods

Search engines such as Google Scholar and PubMed were used to identify all Persian and English-language articles investigating enterococci in Iran from 1996 to 2017. The search terms were “enterococci”, “enterococcal”, “enterococcus”, “Iran”, “bacterial resistance”, “antibiotic resistance” and “resistance”.

Results

Decrease in the resistance trend against ampicillin, gentamycin and ciprofloxacin was observed over a period of 15 years (2001 to 2016) in Iran. During a 10 years period from 2001 to 2015, the rate of resistance among Enterococcus faecalis species was less than Enterococcus faecium. The resistancerate, however, was considerably increased for both species during this period. The mean resistance rates for vancomycin, gentamicin, ciprofloxacin, erythromycin, nitrofurantoin, chloramphenicol, trimethoprim-sulfametoxazol, imipenem and teicoplanin were higher among complicated cases (patients with underlying debilitating disorders) compared to general cases (hospitalized or outpatients with no specific underlying disorder).

Conclusions

E. faecalis and E. faecium showed a rise in the mean resistance against all the antibiotics during a 10-year period from 2010 to 2015. With the exception of penicillin and ampicillin, resistance to all antibiotics was higher amongst complicated cases compared to general patients.

Bacterial Infections in Children With Acute Myeloid Leukemia Receiving Ciprofloxacin Prophylaxis

BACKGROUND

The aim of the study was to describe the incidence and type of bacterial infections associated with the use of ciprofloxacin prophylaxis as single agent in pediatric patients with acute myeloid leukemia (AML).

PROCEDURE

This was a retrospective review of all patients with AML, who were treated according to the AML02 protocol between 2011 and 2015. The medical records were reviewed for any positive cultures from the initiation of the protocol until death or protocol discontinuation. Patient demographics, type of infections, type of isolated bacteria, and intensive care unit admissions were recorded.

RESULTS

A total of 50 patients were evaluated, who were of a mean age of 8 years±5.1 (SD). We identified 77 episodes of bacterial infections in 42 (84%) patients. Among those bacterial infections, 73 episodes were with bacteremia and included 45 (62%) gram-positive bacterial infections, 24 (33%) gram-negative bacterial infections, and 4 (6%) mixed gram-negative and gram-positive bacterial infections. Coagulase-negative Staphylococcus and Viridans streptococci were the most commonly isolated bacteria in 33% and 30% of the episodes, respectively. Seventeen (45%) patients with bacteremia required intensive care unit admission.

CONCLUSIONS

A high rate of bacterial infection was detected in patients who received the AML02 protocol, mainly gram-positive bacterial infections. The prophylactic regimen should be reconsidered for its efficacy, and other antibacterial prophylaxis may be used.

Screening for Intestinal Colonization with Vancomycin Resistant Enterococci and Associated Risk Factors among Patients Admitted to an Adult Intensive Care Unit of a Large Teaching Hospital

INTRODUCTION

Gut colonization with Vancomycin Resistant Enterococci (VRE) increases the risk of acquiring infection during hospital stay. Patients admitted in the ICU's are the major reservoirs for VRE colonization due to higher antibiotic pressure.

AIM

To determine the rate of VRE colonization among patients admitted in the Medical Intensive Care Unit (MICU) and to assess the various risk factors which are associated with VRE colonization.

MATERIALS AND METHODS

This was a prospective study carried out over a period of 18 months from September 2013 to February 2015 in the Jawaharlal Institute of Post graduate Medical Education and Research (JIPMER), Pondicherry, South India. After 48 hours of ICU admission rectal swabs were collected from a total of 302 patients, admitted in MICU. The samples were inoculated on to Bile Esculin Sodium Azide agar with 6mg/L of vancomycin. Vancomycin resistance was confirmed by determination of Minimum Inhibitory Concentration (MIC) by agar dilution method. Isolates were identified up to species level by standard biochemical tests. Vancomycin resistance genes such as van A, van B and van C, were detected by Polymerase Chain Reaction (PCR). Risk factors were assessed by multivariate logistic regression analysis.

RESULTS

The rates of VRE colonization in patients admitted to MICU was 29%. Majority of the isolates were Enterococcus faecium (77.2 %) followed by Enterococcus faecalis (23.8%). All the VRE isolates were positive for van A gene. Increased duration of hospital stay, younger age, consumption of ceftriaxone and vancomycin were found to be significantly associated with VRE colonization in MICU. Among VRE colonized patients, six (4.5%) acquired VRE infection.

CONCLUSION

The rates of VRE colonization in our ICU were similar to other hospitals worldwide. Educating health care workers on the importance of adherence to hand hygiene is essential to bring down VRE colonization rates.

Antimicrobial resistance pattern of Gram-positive bacteria during three consecutive years at the nephrology ward of a tertiary referral hospital in Shiraz, Southwest Iran

Objective:

The aim of the present study was to determine the pattern of antimicrobial resistance of Gram-positive bacteria during three consecutive years at the nephrology ward of Namazi Hospital in Shiraz, Southwest of Iran.

Methods:

During a 3-year period from 2013 to 2015, data of all biological samples of hospitalized patients at the adult nephrology ward of Namazi Hospital were sent to the central laboratory for identification of Gram-positive microorganisms and subsequently, their antimicrobial susceptibility testing by Kirby–Bauer disc diffusion method were analyzed in a retrospective manner.

Findings:

Coagulase-negative Staphylococci (CONS) (38.5%), Staphylococcus aureus (25.4%), and Enterococcus spp. (23.8%) were the most common isolated Gram-positive bacteria from all biological samples. All Enterococcus spp. isolates within the 3 years were resistant to oxacillin. The rate of vancomycin-resistant enterococci (VRE) increased from 40.63% in 2013 to 72.73% in 2015. Enterococcus spp. resistance rates to aminoglycosides during 3 years were above 85%. The frequencies of oxacillin-resistant S. aureus (ORSA) in 2013, 2014, and 2015 were 95.24%, 80.95%, and 36.36%, respectively. Two out of 11 (6.67%) S. aureus isolates were resistant to vancomycin. More than 90% of CONS were sensitive to vancomycin within the study period. The frequency of gentamicin-resistant CONS ranged from 40% to 57.14%.

Conclusion:

The rates of ORSA, VRE, and aminoglycoside-resistant CONS as well as Enterococcus spp. in our clinical setting were considerably high and concerning. These may be due to the failure or lack of infection control activities and antimicrobial selection pressure.

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.

Control of the spread of vancomycin-resistant enterococci in hospitals: epidemiology and clinical relevance

BACKGROUND

The spread of vancomycin-resistant enterococci (VRE), particularly E. faecium, in hospitals leads to many cases of colonization, but only sporadic infections. Detailed and valid risk assessment is needed so that patients at risk can be protected from VRE infection. The principal aims of risk assessment must include not only lowering VRE-associated morbidity and mortality in patients at risk, but also refraining from unnecessary anti-infective measures among those who are not at risk.

METHODS

We selectively searched the PubMed database for pertinent articles on the epidemiology and clinical relevance of VRE in order to derive a uniform and practical hygiene strategy from the available scientific evidence.

RESULTS

Only low-level evidence is available for the interventions studied to date, and most of the recommendations that have been issued can be characterized as expert opinion. As a rule, VRE are not highly pathogenic; they tend to have high rates of colonization, but low rates of infection. The risk factors for colonization with VRE include (among others) the administration of antibiotics and immunosuppressants, prior hospitalization, diarrhea, intubation, and other invasive treatments. The areas of highest risk are hematology/oncology wards, liver transplantation wards, dialysis units, and neonatology wards.

CONCLUSION

The chain of infection can be broken by improved and consistently applied standard hygienic measures (hand and surface disinfection). Some patients are nonetheless at elevated risk of VRE infection. In specific clinical situations, the optimal protection of these patients against VRE infection demands the obligatory enforcement of stricter hygienic measures (contact isolation).

Epidemiological interpretation of studies examining the effect of antibiotic usage on resistance

Bacterial resistance to antibiotics is a growing clinical problem and public health threat. Antibiotic use is a known risk factor for the emergence of antibiotic resistance, but demonstrating the causal link between antibiotic use and resistance is challenging. This review describes different study designs for assessing the association between antibiotic use and resistance and discusses strengths and limitations of each. Approaches to measuring antibiotic use and antibiotic resistance are presented. Important methodological issues such as confounding, establishing temporality, and control group selection are examined.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence and risk factors for VRE colonisation in a tertiary hospital in Melbourne, Australia: a cross sectional study

BACKGROUND

Vancomycin-resistant Enterococcus (VRE) has been established as a significant health-care associated problem since its first isolation in Australia in 1994. In this study, we measured the point prevalence and identified risk factors associated with vanB VRE colonisation in a tertiary care hospital in Melbourne, Australia where VRE has been endemic for 15 years.

METHODS

A hospital-wide point prevalence survey was conducted on October 13, 2008 with colonisation detected using rectal swab culture. Patient's demographic and medical information was collected through a review of medical records. Factors associated with VRE colonisation in univariate analysis were included in multivariate logistic regression model to adjust for confounding.

RESULTS

The prevalence of VRE colonisation on the day of screening was 17.5% (95% CI, 13.7 to 21.9). VRE was detected from patients in each ward with the prevalence ranging from 3% to 29%. Univariate analysis showed the use of any antibiotic, meropenem, ciprofloxacin, diarrhoea and longer length of hospital stay were associated with increased risk of VRE colonisation (p<0.05). However, age, sex, proximity to VRE positive cases, use of other antibiotics including cephalosporins, vancomycin were not associated with increased risk (P>0.05). Multivariate analysis showed the exposure to meropenem (p=0.004), age (≥65 years) (p=0.036) and length of stay ≥7 days (p<0.001) as independent predictors of VRE colonisation.

CONCLUSION

Our study suggests that exposure to antibiotics may have been more important than recent cross transmission for a high prevalence of vanB VRE colonisation at our hospital.

Evaluation of the sensitivity and specificity of criteria for isolation of patients admitted to a specialized cancer hospital

Early isolation of patients possibly colonized by multi-resistant microorganisms can minimize their spread, reducing cases of hospital infection and the related costs. This study aimed to identify the sensitivity and specificity of the criteria for isolation of patients admitted to a specialized cancer hospital. Cross-sectional study with a population of 61 patients coming from other hospitals who were admitted to the hospital between March 1st and August 31th, 2009. At the moment of admission, a data collection instrument was filled out and nasal and anal swabs were collected for microbiological culture. Of the 56 patients who met the isolation criteria, 30 (49.2%) presented positive cultures for multi-resistant microorganisms and methicillin-resistant Staphylococcus aureus was the most frequently identified microorganism. Most patients colonized by multi-resistant microorganisms were isolated at the moment of admission. The sensitivity of the isolation criteria was 90% and the specificity was 6.5%.