Molecular Epidemiology of Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium Isolated from Clinical Specimens in the Northwest of Iran

Detection of Vancomycin-Resistant Enterococci and Vancomycin Resistance Genes in Patients Hospitalized in the Pediatric Intensive Care Unit

Objective: Vancomycin-resistant enterococci (VRE) infection and colonization are seen increasingly frequently, especially among intensive care unit (ICU) patients. In this study, the aim was to detect VRE in swab samples taken from patients hospitalized in the Pediatric ICU (PICU), colonization, and to investigate the clonal relationship between isolates. Materials and Methods: In the present study, swab samples were taken from the external auditory canal (EAC), umbilical region, and rectal region from 82 patients hospitalized in the Çukurova University Balcalı Hospital PICU. The 246 swab samples from patients were inoculated on Kanamycin-Esculin-Azide agar. Isolates were identified with the help of the BBL Crystal Gram-Positive identification system. The susceptibility of the isolates to vancomycin (30 µg) was investigated by Kirby-Bauer disk diffusion method according to CLSI criteria. VanA-VanB genes in phenotypically defined vancomycin-resistant enterococci were investigated by Polymerase Chain Reaction (PCR) method. The clonal relationship between vancomycin-susceptible (VSE) and -resistant enterococci was determined by the SmaI-PFGE method. Results: A total of 49 (20.3%) enterococcal strains were isolated from 246 swab samples from the patients, of which 14 (28.5%) were VRE. Of the enterococci isolates, 27 (55.10%) were E. faecium and 13 (26.53%) were E. feacalis. While VanA type resistance was detected in 11 of the vancomycin-resistant E. faecium and E. feacalis isolates, VanB type resistance was not detected in any sample. There was no significant clonal relationship between the isolates. Conclusion: Although the prevalence of VRE in the PICU was high throughout the study, no enterococcal infection was observed.

Enterococcus faecalis Bacteriophage vB_EfaS_efap05-1 Targets the Surface Polysaccharide and ComEA Protein as the Receptors

Enterococcus faecalis is a Gram-positive opportunistic pathogen that causes nosocomial infections in humans. Due to the growing threat of antibiotic resistance of E. faecalis, bacteriophage therapy is a promising option for treating of E. faecalis infection. Here, we characterized a lytic E. faecalis bacteriophage vB_EfaS_efap05-1 with a dsDNA genome of 56,563 bp. Phage vB_EfaS_efap05-1 had a prolate head and a tail, and belongs to Saphexavirus which is a member of Siphoviridae. Efap05-1 uses either surface polysaccharide or membrane protein ComEA as the receptor because the mutation of both genes (ComEA and UDP-glucose 4-epimerase galE) prevents phage adsorption and leads to phage resistance, and complementation of ComEA or galE could recover its phage sensitivity. Our results provided a comprehensive analysis of a new E. faecalis phage and suggest efap05-1 as a potential antimicrobial agent.

Heterologous Expression and Application of Multicopper Oxidases from Enterococcus spp. for Degradation of Biogenic Amines

BACKGROUND

Biogenic amines are harmful to human health at a certain extent. As a kind of biogenic amine oxidase, multicopper oxidase can be used to degrade them. Currently, the literature about enzyme from Enterococcus spp. are limited, and recombinant multicopper oxidase might be an effective way to degrade biogenic amines.

OBJECTIVE

(i) Select and identify strains that can degrade biogenic amines, (ii) overexpress enzyme from Enterococcus spp., (iii) measure gene expression and probe amine-degradation differences among strains (native, E. coli DH5α, and L. delbruckii), and (iv) examine the biochemical properties of recombinant multicopper oxidase, (v) apply the recombinant enzyme into smoked horsemeat sausage.

METHODS

Reverse transcription PCR and high-performance liquid chromatography were performed to examine gene expression and amine degradation rate.

RESULTS

The results demonstrated that target enzymes were successfully overexpressed, accompanied by increased amine-degrading activity (P <0.05). Gene from E. faecalis M5B was expressed in L. delbrueckii resulted in degradation rates for phenylethylamine, putrescine, histamine and tyramine of 54%, 52%, 70% and 40%, respectively, significantly higher than achieved by other recombinant strains.

CONCLUSION

In this work, gene expression levels were higher in recombinant M5B than recombinant M2B, regardless of host. E. coli is more stable to express multicopper oxidase. Besides, the amine-degrading ability was markedly increased in the two recombinant strains. After prolonged incubation, the recombinant enzyme could degrade three amines, and it displayed high alkali resistance and thermostability.

High clinical impact of rapid susceptibility testing on CHROMID ESBL® medium directly from swabs

Background

Antibiotic resistance is a serious public health challenge exacerbated by the widespread use of β-lactam and glycopeptide antibiotics. The identification of resistances is crucial, and CHROMID ESBL medium has been developed to detect enterobacteria with extended-spectrum β-lactamases (ESBL). The objective of this study was to evaluate the potential of this medium to detect other types of resistant bacteria.

Methods

Vancomycin, cefoxitin, imipenem, and cefepime disks were used to measure growth on CHROMID ESBL medium of β-lactam-resistant Gram-negative (83 with ESBL, 57 with carbapenemases, 35 with AmpC and 3 Stenotrophomonas maltophilia) and Gram-positive [37 vancomycin-susceptible (vancoS) microorganisms and 21 vancomycin-resistant (vancoR) Enterococcus faecium] clinical isolates (retrospective study) and colonization by the aforementioned bacteria (prospective study), using 649 rectal swabs, 314 pharyngeal swabs, and 44 swabs from other localizations.

Results

Retrospective study: species grown on the medium exhibited different colors. Growth on the medium was observed for: all ESBL enterobacteria, which were susceptible to imipenem and cefoxitin; 95% of isolates with carbapenemases, mostly resistant to imipenem; 80% of those with AmpC; 86% of vancoR E. faecium isolates; and 42% of vancoS E. faecalis isolates, with large growth inhibition halos around the vancomycin disk. Prospective study: vancoR E. faecium, ESBL Klebsiella, Pseudomonas with carbapenemases, A. baumannii (mostly from rectal swabs), S. maltophilia, Achromobacter xylosoxidans, and Burkholderia cenocepacia (mostly from pharyngeal swabs) were isolated from the 246 positive samples.

Conclusions

CHROMID ESBL medium permitted the differential growth of Gram-negative bacteria, many with ESBL and carbapenemases. ESBL enterobacteria were susceptible to imipenem, carbapenemase-producing microorganisms grew around the imipenem disk, and vancoR E. faecium was isolated on the medium. Results of the prospective study demonstrate the potential clinical relevance of this medium. S. maltophilia was more frequently detected with pharyngeal swabs and ESBL Klebsiella, A. baumannii, and Pseudomonas with rectal swabs.

Prevalence of Vancomycin resistant enterococci (VRE) in Ethiopia: a systematic review and meta-analysis

Background

The emergence of Vancomycin resistant enterococci (VRE) poses a major public health problem since it was first reported. Although the rising rates of VRE infections are being reported elsewhere in the worldwide; there is limited national pooled data in Ethiopia. Therefore, this study was aimed to estimate the pooled prevalence of VRE and antimicrobial resistance profiles of enterococci in Ethiopia.

Methods

Literature search was done at PubMed, EMBASE, Google scholar, African Journals online (AJOL) and Addis Ababa University repository following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Both published and unpublished studies reporting the prevalence of VRE until June 30, 2019 were included. Data were extracted using Microsoft Excel and copied to Comprehensive Meta-analysis (CMA 2.0) for analysis. Pooled estimate of VRE was computed using the random effects model and the 95% CIs. The level of heterogeneity was assessed using Cochran’s Q and I² tests. Publication bias was checked by visual inspection of funnel plots and Begg’s and/or Egger’s test.

Results

Twenty studies fulfilled the eligibility criteria and found with relevant data. A total of 831 enterococci and 71 VRE isolates were included in the analysis. The pooled prevalence of VRE was 14.8% (95% CI; 8.7–24.3; I² = 74.05%; P <  0.001). Compared to vancomycin resistance, enterococci had higher rate of resistance to Penicillin (60.7%), Amoxicillin (56.5%), Doxycycline (55.1%) and Tetracycline (53.7%). Relatively low rate of resistance was found for Daptomycin and Linezolid with a pooled estimate of 3.2% (95% CI, 0.5–19.7%) and 9.9% (95% CI, 2.8–29.0%); respectively. The overall pooled multidrug resistance (MDR) rate of enterococci was 60.0% (95% CI, 42.9–75.0%).

Conclusion

The prevalence of VRE and drug resistant enterococci are on the rise in Ethiopia. Enterococcal isolates showed resistance to one or more of the commonly prescribed drugs in different or the same drug lines. Multidrug resistant (MDR) enterococci were also found. Although the rates were low, the emergence of resistance to Daptomycin and Linezolid is an alarm for searching new ways for the treatment and control of VRE infections. Adherence to antimicrobial stewardship, comprehensive testing and ongoing monitoring of VRE infections in the health care settings are required.

Comparative analysis of Enterococcus faecalis and Enterococcus faecium strains isolated from clinical samples and traditional cheese types in the Northwest of Iran: antimicrobial susceptibility and virulence traits

This research was conducted using 50 samples of popular traditional cheeses and 160 enterococcal clinical isolates. Phenotypic and genotypic methods used for identification of enterococci. Then, the incidences of antibacterial resistance and virulence traits were investigated. In total, 165 E. faecalis and 43 E. faecium obtained from traditional cheeses and different clinical isolates were analyzed in the study. Antibiotic susceptibility testing revealed 175(84.1%) isolates with multi-drug resistance (MDR) patterns, which was more common among clinical sources. The predominant virulence profile, including gelE, asa1 and cpd was detected within 47 (22.6%) of the MDR isolates. Our results showed that traditional cheeses and clinical E. faecalis isolates have distinct patterns of virulence traits. The identified enterococci with antibiotic resistance and associated virulence factors, could provide a potential risk to the public health.