Occurrence of the vanA and vanC2/C3 genes in Enterococcus species isolated from poultry sources in Malaysia

Prevalence of Vancomycin-Resistant Enterococcus (VRE) in Poultry in Malaysia: The First Meta-Analysis and Systematic Review

Databases such as PubMed, Scopus and Google Scholar were searched. Data extraction and assessment of study protocol was done by two independent reviewers and the results were reviewed by a third. OpenMeta analyst and comprehensive meta-analysis (CMA) were used for the meta-analysis. The random effect model was used, publication bias and between-study heterogeneity was assessed. Seventeen studies were added to the final meta-analysis. Studies were sampled from 2000–2018 and of the 8684 isolates tested, 2824 were VRE. The pooled prevalence of VRE among poultry in Malaysia was estimated at 24.0% (95% CI; 16.7–33.1%; I² = 98.14%; p < 0.001). Between-study variability was high (t² = 0.788; heterogeneity I² = 98.14% with heterogeneity chi-square (Q) = 858.379, degrees of freedom (df) = 16, and p < 0.001). The funnel plot showed bias which was confirmed by Egger’s test and estimates from the leave-one-out forest plot did not affect the pooled prevalence. Pooled prevalence of VRE in chickens and ducks were 29.2% (CI = 18.8–42.5%) and 11.2%, CI = 9.0–14.0%) respectively. Enterococcus faecalis was reported most with more studies being reported in Peninsular Malaysia Central region and used antibiotic disc diffusion as detection method. Increased surveillance of VRE in poultry in Malaysia is required.

Global Prevalence of Vancomycin-Resistant Enterococci in Food of Animal Origin: A Meta-Analysis

Vancomycin-resistant enterococci (VRE) are a leading cause of nosocomial infections in patients worldwide. VRE contamination in food of animal origin may create a risk for human health. This study was conducted to estimate the pooled prevalence of VRE in food of animal origin worldwide, to assess the result heterogeneity, and to determine cumulative evidence and the trend of the prevalence over time. Relevant studies were retrieved from PubMed, Scopus, and Web of Science. A random-effects model was used to calculate the pooled prevalence of VRE in food of animal origin. Subgroup meta-analysis was used to assess the heterogeneity of the results. A cumulative meta-analysis and meta-regression were conducted to determine cumulative evidence and the trend of the prevalence of VRE in food of animal origin over time, respectively. Of the 1352 retrieved studies, 50 articles were included. The pooled prevalence of VRE in food of animal origin was 11.7% (95% confidence interval [95% CI] = 8.4 to 16.0). Subgroup meta-analyses showed a significant difference in the prevalence of VRE for two characteristics. First, for the source of food, the prevalence of VRE was highest in aquatic food (43.4% [95% CI = 28.4 to 59.7]) and lowest in dairy food (4.1% [95% CI = 1.7 to 9.8]). Second, for continents, the prevalence of VRE was highest in Africa (18.5% [95% CI = 12.8 to 26.1]) and lowest in North America (0.3% [95% CI = 0.1 to 1.1]). Cumulative evidence showed two distinct features in two different periods. The pooled prevalence of VRE rapidly decreased from 79.3% in 1998 to 13.1% in 2003; it has slightly fluctuated between 10.5% and 20.5% since 2004. The results of the meta-regression indicated that the prevalence gradually decreased over time. In conclusion, the estimate of overall VRE prevalence worldwide in food of animal origin was ∼12%, indicating the burden of VRE contamination in food of animal origin.

Molecular characteristics and comparative genomics analysis of a clinical Enterococcus casseliflavus with a resistance plasmid

Purpose

The aim of this work was to investigate the molecular characterization of a clinical Enterococcus casseliflavus strain with a resistance plasmid.

Materials and methods

En. casseliflavus EC369 was isolated from a patient in a hospital in southern China. The minimum inhibitory concentration was found by means of the agar dilution method to determine the antimicrobial susceptibilities of the strains. Whole-genome sequencing and comparative genomics analysis were performed to analyze the mechanism of antibiotic resistance and the horizontal gene transfer of the resistance gene-related mobile genetic elements.

Results

En. casseliflavus EC369 showed resistance to erythromycin, kanamycin, and streptomycin, but was susceptible to vancomycin, ampicillin, and streptothricin and other antimicrobials. There were six resistance genes (aph3′, ant6, bla, sat4, and two ermBs) carried by a transposon identified on the plasmid pEC369 and a complete resistance gene cluster of vancomycin and a tet (M) gene encoded on the chromosome. This is the first complete plasmid sequence reported in clinically isolated En. casseliflavus. The plasmid with the greatest sequence identity with pEC369 was the plasmid of Enterococcus sp. FDAARGOS_375, followed by the plasmids of Enterococcus faecium strains F12085 and pRE25, whereas the sequence with the greatest identity to the resistance genes carrying a transposon of pEC369 was on the chromosome of Staphylococcus aureus strain GD1677.

Conclusion

The resistance profiles of En. casseliflavus EC369 might contribute to the resistance genes encoded on the plasmid. The fact that the most similar sequence to the transposon carrying resistance genes of pEC369 was encoded in the chromosome of a S. aureus strain provides insights into the mechanism of dissemination of multidrug resistance between bacteria of different species or genera through horizontal gene transfer.

Vancomycin-resistant Enterococcus – A Review From a Singapore Perspective

Introduction: Vancomycin-resistant enterococcus (VRE) can cause serious infections in vulnerable, immunocompromised patients. Materials and Methods: In this article, we summarise current data on epidemiology, detection, treatment and prevention of VRE. Results: VRE was first isolated in Singapore in 1994 and until 2004 was only sporadically encountered in our public hospitals. After 2 outbreaks in 2004 and in 2005, VRE has become established in our healthcare institutions. Multiple studies have shown that VRE spreads mainly via contaminated hands, cloths and portable equipment carried by healthcare workers. Conclusions: Only a comprehensive programme (consisting of active surveillance, isolation of colonised/infected patients, strict adherence to proper infection control practices and anti-microbial stewardship) can limit the spread of these organisms. In addition to monitoring the compliance with traditional infection control measures, new strategies that merit consideration include pre-emptive isolation of patients in high-risk units and molecular techniques for the detection of VRE. Keywords: Antibiotic resistance, Infection control, Outbreaks, Surveillance

A nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistance genes in Enterococcus species

BACKGROUND

Enterococci have emerged as a significant cause of nosocomial infections in many parts of the world over the last decade. The most common enterococci strains present in clinical isolates are E. faecalis and E. faecium which have acquired resistant to either gentamicin or vancomycin. The conventional culture test takes 2-5 days to yield complete information of the organism and its antibiotic sensitivity pattern. Hence our present study was focused on developing a nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistant enterococci (V-BiA-RE). This assay simultaneously detects 8 genes namely 16S rRNA of Enterococcus genus, ddl of E. faecalis and E. faecium, aacA-aphD that encodes high level gentamicin resistance (HLGR), multilevel vancomycin resistant genotypes such as vanA, vanB, vanC and vanD and one internal control gene.

RESULTS

Unique and specific primer pairs were designed to amplify the 8 genes. The specificity of the primers was confirmed by DNA sequencing of the nanoplex PCR products and BLAST analysis. The sensitivity and specificity of V-BiA-RE nanoplex PCR assay was evaluated against the conventional culture method. The analytical sensitivity of the assay was found to be 1 ng at the DNA level while the analytical specificity was evaluated with 43 reference enterococci and non-enterococcal strains and was found to be 100%. The diagnostic accuracy was determined using 159 clinical specimens, which showed that 97% of the clinical isolates belonged to E. faecalis, of which 26% showed the HLGR genotype, but none were vancomycin resistant. The presence of an internal control in the V-BiA-RE nanoplex PCR assay helped us to rule out false negative cases.

CONCLUSION

The nanoplex PCR assay is robust and can give results within 4 hours about the 8 genes that are essential for the identification of the most common Enterococcus spp. and their antibiotic sensitivity pattern. The PCR assay developed in this study can be used as an effective surveillance tool to study the prevalence of enterococci and their antibiotic resistance pattern in hospitals and farm animals.

Absence of VanA- and VanB-containing enterococci in poultry raised on nonintensive production farms in Brazil

We examined cloacal samples from poultry raised on nonintensive production farms in Brazil for the presence of vancomycin-resistant enterococci. No VanA- or VanB-containing enterococci were identified in a total of 200 cloacal swabs. The most prevalent species were Enterococcus gallinarum (vanC1; 13.0%) and E. casseliflavus (vanC2/3; 5.5%).

Resistance to gentamicin and vancomycin in enterococcal strains isolated from retail broiler chickens in Japan

A total of 137 Enterococcus strains isolated from chicken meat were subjected to antimicrobial susceptibility tests. Strains with the vanCl gene were isolated from seven of nine samples of chicken meat processed in Japan and from all chickens from China and Brazil between July 2001 and April 2002. The pulsed-field gel electrophoresis (PFGE) patterns of the isolates were distinguishable from each other, suggesting that VanCl-type vancomycin-resistant Enterococcus is preferentially colonized in broiler chickens in these countries. The incidence of high-level gentamicin resistant (HLGR) enterococci that harbored the aac(6')-le-aph(2")-la or aph(2')-Id gene varied among the countries from which the chickens originated (Japan, 2 of 65; China, 11 of 43; Brazil, 6 of 29). Moreover, the PFGE patterns of the HLGR strains were distinguishable from each other, except for two strains obtained from chickens from Brazil. The results suggest that HLGR Enterococcus is highly prevalent in broiler chickens.

Antibiotics in animal feed and their role in resistance development

Animals and humans constitute overlapping reservoirs of resistance, and consequently use of antimicrobials in animals can impact on public health. For example, the occurrence of vancomycin-resistant enterococci in food-animals is associated with the use of avoparcin, a glycopeptide antibiotic used as a feed additive for the growth promotion of animals. Vancomycin-resistant enterococci and vancomycin resistance determinants can therefore spread from animals to humans. The bans on avoparcin and other antibiotics as growth promoters in the EU have provided scientists with a unique opportunity to investigate the effects of the withdrawal of a major antimicrobial selective pressure on the occurrence and spread of antimicrobial resistance. The data shows that although the levels of resistance in animals and food, and consequently in humans, has been markedly reduced after the termination of use, the effects on animal health and productivity have been very minor.

Vancomycin-resistant enterococci in shellfish, unchlorinated waters, and chicken

Vancomycin-resistant enterococci (VRE) have been a cause of increasing concern chiefly regarding the infection of hospital patients. There is suspicion, but limited evidence, that food and environmental spread may be important. Biomonitoring by examination of bivalve shellfish was used to assess the occurrence of VRE entering the environment. Using pre-enrichment and Lewisham and Slanetz and Bartley agars, 2/125 (1.6%) of shellfish were found to contain enterococci resistant to high levels of vancomycin. Lewisham agar allows relatively rapid identification of VRE. In a second phase of the work using pre-enrichment and Slanetz and Bartley agar, 4/151 (2.7%) shellfish and 5/27 (18.5%) raw chickens contained VRE. Using filtration and pre-enrichment, no VRE were found in 54 unchlorinated water samples. The study shows that environmental prevalence of VRE is low, and that raw chickens are frequently contaminated.