Multidrug-resistant Enterococcus Research Articles

Efficacy of Omadacycline against Multidrug-Resistant Enterococcus faecium Strains in a Mouse Peritonitis Model.

Omadacycline (OMC) showed better in vitro potency than daptomycin (DAP) or vancomycin (VAN) against Vanr, Ampr, DAP-nonsusceptible, linezolid-resistant, cfr(B)+ Enterococcus faecium strains. In a mouse peritonitis model, OMC also showed significantly better animal survival during the study and at its end than DAP or VAN with these E. faecium strains. However, OMC, DAP, and VAN showed comparable in vitro and in vivo efficacies against a non-vancomycin-resistant, tetracycline-resistant, DAP-susceptible E. faecium strain.

Characteristics of High-Level Aminoglycoside-Resistant Enterococcus faecalis Isolated from Bulk Tank Milk in Korea.

Simple SummaryAminoglycosides are used to treat various infections in veterinary and human medicine. However, with the emergence of high-level aminoglycoside resistance in human and food-producing animals, the synergism of aminoglycosides with beta-lactam or glycopeptide is being threatened. Moreover, the environmental mastitis-causing agent, enterococci, has emerged as a cause of nosocomial infection due to its antimicrobial resistance. Therefore, the purpose of this study was to investigate the characteristics of high-level aminoglycoside-resistant Enterococcus faecalis isolated from bulk tank milk in Korea. It showed that 185 (61.5%) isolates out of 301 were high-level aminoglycoside resistant, while 149 isolates were multidrug resistant.Enterococci, which are considered environmental mastitis-causing pathogens, have easily acquired aminoglycoside-resistant genes that encode various aminoglycoside-modifying enzymes (AME). Therefore, this study was conducted to compare the distribution of high-level aminoglycoside-resistant (HLAR) and multidrug-resistant (MDR) Enterococcus faecalis (E. faecalis) bacteria isolated from bulk tank milk in four dairy companies in Korea. Moreover, it analyzed the characteristics of their antimicrobial resistance genes and virulence factors. Among the 301 E. faecalis bacteria studied, 185 (61.5%) showed HLAR with no significant differences among the dairy companies. Furthermore, 129 (69.7%) of the 185 HLAR E. faecalis showed MDR without significant differences among companies. In contrast, HLAR E. faecalis from companies A, B, and C were significantly higher in resistance to the four classes than those in company D, which had the highest MDR ability against the three antimicrobial classes (p < 0.05). In addition, in the distribution of AME genes, 72 (38.9%) and 36 (19.5%) of the isolates carried both aac(6′)Ie-aph(2″)-la and ant(6)-Ia genes, and the ant (6)-Ia gene alone, respectively, with significant differences among the companies (p < 0.05). In the distribution of virulence genes, the ace (99.5%), efa A (98.9%), and cad 1 (98.4%) genes were significantly prevalent (p < 0.05). Thus, our results support that an advanced management program by companies is required to minimize the dissemination of antimicrobial resistance and virulence factors.

Industrial dog food is a vehicle of multidrug-resistant enterococci carrying virulence genes often linked to human infections

The increase in the number of pets in recent years has been followed by an exponential growth of the industrial pet food sector, which has been accompanied by new food safety risks, namely antibiotic resistance. The aim of this study was to investigate whether dog food commercially available in Portugal is a reservoir of clinically-relevant antibiotic resistant Enterococcus. Fifty-five samples (25 brands; 22 wet, 14 raw frozen, 8 dry, 7 treats and 4 semi-wet) were collected on 9 commercial surfaces in the Porto region (September 2019 to January 2020). Most samples were obtained from brands that are commercialized worldwide (n = 21/25). Sample (25 g) processing included pre-enrichment and enrichment steps in culture media without/with 3 antibiotics, and then plating into selective media without/with the same antibiotics. Susceptibility was studied for 13 antibiotics (disk diffusion; Etest; microdilution) according to EUCAST/CLSI. Clinically-relevant species (E. faecium and E. faecalis), antibiotic resistance (vanA, vanB, optrA, poxtA) and virulence (e.g. ptsD, esp, sgrA) genes were identified by PCR. Other species of Enterococcus were identified by MALDI-TOF MS. Clonality was established by MLST in selected isolates.Enterococcus (n = 184; 7 species; >85% E. faecium and E. faecalis) were detected in 30 samples (54%) of different types (14 raw, 16 heat treated-7 dry, 6 wet, 3 treats). E. faecium and E. faecalis were more frequent in dry and wet samples, respectively. More than 40% of enterococci recovered were resistant to erythromycin, tetracycline, quinupristin-dalfopristin, streptomycin, gentamicin, chloramphenicol, ampicillin or ciprofloxacin, and to a lesser extent to linezolid (23%; optrA, poxtA) or vancomycin and teicoplanin (2% each; vanA). Multidrug-resistant isolates (31%), including to vancomycin and linezolid, were obtained mostly from raw foods, although also detected in wet samples or treats, and mainly from culture media supplemented with antibiotics. Samples subjected to thermal treatment mostly carried non-MDR isolates. The variety of clones observed included strains previously identified in hospitalized patients (E. faecium ST17/ST80; E. faecalis ST40), farm animals, pets and environmental strains. This study shows that dog food from international brands is a vehicle of clinically-relevant enterococci carrying resistance to last resort antibiotics and relevant virulence genes, thus positioning pet food as an important source of antibiotic resistance spread within the One Health context. The high incidence of Enterococcus in a variety of dog food samples indicates the need to review selection of raw materials, manufacturing and hygiene practices in an emerging food sector growing worldwide.

New cytochalasan alkaloids and cyclobutane dimer from an endophytic fungus Cytospora chrysosperma in Hippophae rhamnoides and their antimicrobial activities

Three new cytochalasan alkaloids, cytochrysins A-C (1–3), and a new cyclobutane dimer, cytospodimer A (4), along with three known compounds (5–7), were isolated from the solid culture of Cytospora chrysosperma, an endophytic fungus isolated from Hippophae rhamnoides. Their structures were determined by a combination of spectroscopy and single-crystal X-ray crystallography. Compound 1 showed significant antibacterial activity against multi-drug resistant Enterococcus faecium with an MIC value of 25 μg/mL, and compound 3 against methicillin-resistant Staphylococcus aureus with an MIC value of 25 μg/mL.

Occurrence of multidrug-resistant Enterococcus faecium isolated from environmental samples.

Enterococcus species are present in the microbiota of humans and animals and have also been described in the environment. Among the species, Enterococcus faecium is one of the main pathogens associated with nosocomial infections worldwide. Enterococcus faecium isolates resistant to different classes of antimicrobials have been increasingly reported, including multidrug-resistant (MDR) isolates in environmental sources, which is worrying. Therefore, this study aimed to characterize E. faecium isolates obtained from soil and water samples regarding antimicrobial resistance and virulence determinants. A total 40 E. faecium isolates were recovered from 171 environmental samples. All isolates were classified as MDR, highlighting the resistance to the fluoroquinolones class, linezolid and vancomycin. Furthermore, high-level aminoglycoside resistance and high-level ciprofloxacin resistance were detected in some isolates. Several clinically relevant antimicrobial resistance genes were found, including vanC1, ermB, ermC, mefAE, tetM, tetL, ant(6')-Ia, ant(4')-Ia, aph(3')-IIIa and aac(6')-Ie-aph(2″)-Ia. Three virulence genes were detected among the MDR E. faecium isolates, such as esp, gelE and ace. The results of this study contribute to a better understanding of MDR E. faecium isolates carrying antimicrobial resistance and virulence genes in environmental sources and report for the first time in the world the presence of vanC1-producing E. faecium isolated from soil.

N-terminal acetylation of antimicrobial peptide L163 improves its stability against protease degradation.

Antimicrobial peptide L163 was computationally designed by our laboratory; L163 is active against multidrug-resistant (MDR) bacteria but is easily degraded in the plasma and by trypsin. Amino acid substitution, cyclization, and amino-terminal (N-terminal) acetylation were performed to obtain L163 analogs with high stability in the plasma and in trypsin solutions. The stability, antimicrobial activity, and biosafety of L163 and its analogs were investigated. Comparison with unmodified L163 indicated that N-terminal acetylation enhanced the stability against pH, plasma, and trypsin degradation, and phenylalanine (Phe) substitution for leucine (Leu) and cysteine bridge (S-S) cyclization decreased the stability. N-terminal acetylation also enhanced antimicrobial activity against MDR Streptococcus Sc181, Listeria monocytogenes, and Enterococcus E1478F; did not change the activity against MDR Staphylococcus aureus 9, Staphylococcus sciuri P254, and Staphylococcus aureus RN4220; and decreased the activity against Candida tropicalis, Candida albicans, and Enterococcus faecalis Fbc35. Phe substitution for Leu and S-S cyclization decreased the antimicrobial activity. The negative effect of these modifications was detected against biofilm formation by the tested microbial strains. Comparison of Phe substitution for Leu and S-S cyclization indicated that N-terminally acetylated L163 (L163-Ac) is the best candidate. L163-Ac peptide had the highest antibacterial activity and enhanced tolerance to temperature, pH, plasma, and trypsin and low toxicity.

Rethinking Manure Application: Increase in Multidrug-Resistant Enterococcus spp. in Agricultural Soil Following Chicken Litter Application.

The current study investigated the impact of chicken litter application on the abundance of multidrug-resistant Enterococcus spp. in agricultural soil. Soil samples were collected from five different strategic places on a sugarcane farm before and after manure application for four months. Chicken litter samples were also collected. Enterococci were enumerated using the Enterolert®/Quanti-Tray 2000® system and confirm and differentiated into species using real-time PCR. The antibiotic susceptibility profile of the isolates was determined using the disk diffusion method following the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The overall mean bacterial count was significantly higher (p < 0.05) in manure-amended soil (3.87 × 107 MPN/g) than unamended soil (2.89 × 107 MPN/g). Eight hundred and thirty-five enterococci (680 from soil and 155 from litter) were isolated, with E. casseliflavus being the most prevalent species (469; 56.2%) and E. gallinarum being the least (16; 1.2%). Approximately 56% of all the isolates were resistant to at least one antibiotic tested, with the highest resistance observed against tetracycline (33%) and the lowest against chloramphenicol (0.1%); 17% of E. faecium were resistant to quinupristin-dalfopristin. Additionally, 27.9% (130/466) of the isolates were multidrug-resistant, with litter-amended soil harbouring more multidrug-resistant (MDR) isolates (67.7%; 88/130) than unamended soil (10.0%; 13/130). All isolates were susceptible to tigecycline, linezolid and gentamicin. About 7% of the isolates had a multiple antimicrobial resistance index > 0.2, indicative of high antibiotic exposure. Although organic fertilizers are regarded as eco-friendly compared to chemical fertilizers for improving soil fertility, the application of untreated animal manure could promote the accumulation of antibiotics and their residues and antibiotic-resistant bacteria in the soil, creating an environmental reservoir of antimicrobial resistance, with potential human and environmental health risks.

Unraveling Mechanisms and Epidemic Characteristics of Nitrofurantoin Resistance in Uropathogenic Enterococcus faecium Clinical Isolates.

PurposeMultidrug-resistant (MDR) Enterococcus faecium is an important nosocomial pathogen causing urinary tract infection, and the reapplication of nitrofurantoin (NIT) in the clinic has attracted great attention. This study aims to explore the NIT resistance mechanisms and epidemiological characteristics of E. faecium clinical isolates.Patients and MethodsA total of 633 E. faecium clinical isolates was obtained from urine samples in a clinical teaching hospital during 2017–2018. Among them, 40 NIT-resistant strains, and a similar number of -intermediate and -susceptible strains were isolated. The minimum inhibitory concentrations (MICs) of NIT were detected by agar dilution method. The prevalence and mutations of nitroreductase-encoding genes ef0404 and ef0648 were explored by polymerase chain reaction (PCR), followed by efflux pump inhibition test and quantitative real-time PCR (qRT-PCR) to investigate the resistance mechanisms of NIT. Furthermore, the epidemiological characteristics were detected by multilocus sequence typing (MLST).ResultsThe carrying rates of nitroreductase in NIT-susceptible, -intermediate, and -resistant isolates were 100%, 50%, and 20%, respectively. After exposure to the efflux pump inhibitor, the MIC of 12 E. faecium decreased by ≥4-fold. However, the efflux pump genes efrAB, emeA, and oqxAB were not overexpressed in NIT-resistant E. faecium isolates. Moreover, MLST analysis revealed that all the NIT-resistant isolates belonged to CC17, of which 30 (75%) were associated with ST78.ConclusionThis study has established for the first time that the absence of EF0404 and EF0648 is the main mechanism of NIT resistance in E. faecium. Our findings are likely to fill the knowledge gap pertaining to the NIT resistance mechanism in E. faecium and provide important insights for molecular epidemiological characteristics analysis.

Intestinal carriage of vancomycin\u2010resistant Enterococcus spp. among high\u2010risk patients in university hospitals in Serbia: first surveillance report

BackgroundThe screening for intestinal carriage of vancomycin-resistant Enterococcus spp. (VRE) among high risk patients in the Balkan region and molecular epidemiology of VRE is insufficiently investigated, yet it could be of key importance in infection control. The aim of this study was to provide baseline data on VRE intestinal carriage among high-risk patients in Serbian university hospitals, to determine the phenotypic/genotypic profiles of the isolated VRE, to obtain knowledge of local resistance patterns and bridge the gaps in current VRE surveillance.MethodsThe VRE reservoir was investigated using stool samples from 268 inpatients. Characterization of isolated VRE stains consisted of BD Phoenix system, genotypic identification, glycopeptide and quinupristin–dalfopristin (Q–D) resistance probing, virulence gene (esp, hyl, efaA, asa1, gelE, cpd) detection and MLVA. Biofilm formation was evaluated by the microtiter plate method.ResultsVRE carriage prevalence among at-risk patients was 28.7%. All VRE strains were vanA positive multidrug-resistant Enterococcus faecium (VRfm), harboring ermB-1 (38.9%), esp (84%), efaA (71.2%), hyl (54.5%), asa1 (23.4%), gelE and cpd (11.6%) each. Ability of biofilm production was detected in 20.8%. Genetic relatedness of the isolates revealed 13 clusters, heterogeneous picture and 25 unique MTs profiles.ConclusionThe obtained prevalence of VRE intestinal carriage among high-risk inpatients in Serbia is higher than the European average, with high percentage of multidrug resistance. The emergence of resistance to Q–D is of particular concern. Close monitoring of pattern of resistance and strict adherence to specific guidelines are urgently needed in Serbia.

Bacteriophages to Control Multi-Drug Resistant Enterococcus faecalis Infection of Dental Root Canals.

Phage therapy is an alternative treatment to antibiotics that can overcome multi-drug resistant bacteria. In this study, we aimed to isolate and characterize lytic bacteriophages targeted against Enterococcus faecalis isolated from root canal infections obtained from clinics at the Faculty of Dentistry, Ismalia, Egypt. Bacteriophage, vB_ZEFP, was isolated from concentrated wastewater collected from hospital sewage. Morphological and genomic analysis revealed that the phage belongs to the Podoviridae family with a linear double-stranded DNA genome, consisting of 18,454, with a G + C content of 32.8%. Host range analysis revealed the phage could infect 10 of 13 E. faecalis isolates exhibiting a range of antibiotic resistances recovered from infected root canals with efficiency of plating values above 0.5. One-step growth curves of this phage showed that it has a burst size of 110 PFU per infected cell, with a latent period of 10 min. The lytic activity of this phage against E. faecalis biofilms showed that the phage was able to control the growth of E. faecalis in vitro. Phage vB_ZEFP could also prevent ex-vivo E. faecalis root canal infection. These results suggest that phage vB_ZEFP has potential for application in phage therapy and specifically in the prevention of infection after root canal treatment.

Emerging crisis of multidrug-resistant enterococci from a rural tertiary care hospital of North India

INTRODUCTION: Enterococci are emerging as a major pathogen causing a variety of hospital-acquired nosocomial infections and community-acquired infections contributing significantly to patient's morbidity and mortality. The emergence of multidrug-resistant enterococci worsens the problem as multidrug resistance leaves fewer therapeutic options for clinicians in treating life-threatening infections. MATERIALS AND METHODS: This was an observational study carried out from March 2019 to February 2020. Antimicrobial susceptibility testing of enterococci was done by Kirby–Bauer disc diffusion method, and results were interpreted as per the Clinical and Laboratory Standards Institute guidelines 2019. RESULTS: Multidrug-resistant enterococci were reported to be 62.7%. A variable antimicrobial susceptibility pattern was seen with different antibiotics. Majority of isolates were resistant to β-lactam (96.6%), and high-level aminoglycoside resistance was seen in 39% of isolates. Glycopeptide resistance was observed in teicoplanin (14.6%). No vancomycin and linezolid resistance was noted. CONCLUSION: The prevalence of multidrug-resistant enterococci was reported to be 63%; the resistance was more common in Enterococcus faecium as compared to Enterococcus faecalis. This study highlights the emergence of multidrug-resistant enterococci, especially to high-level aminoglycoside and glycopeptide which poses a serious therapeutic challenge.

The Prevalence of Virulent and Multidrug-Resistant Enterococci in River Water and in Treated and Untreated Municipal and Hospital Wastewater.

The aim of this study is to describe the drug resistance and virulence of enterococci in river water sampled downstream (DRW) and upstream (URW) from the wastewater discharge point, to determine the pool of virulent and drug-resistant enterococci in untreated wastewater (UWW) and the extent to which these bacteria are eliminated from hospital wastewater (HWW) and municipal wastewater treated (TWW) by biological and mechanical methods in a wastewater treatment plant (WWTP). A total of 283 strains were identified with the use of culture-dependent methods and PCR, including seven different species including E. faecalis and E. faecium which were predominant in all analyzed samples. Majority of the strains were classified as multidrug resistant (MDR), mostly on streptomycin and trimethoprim. Strains isolated from wastewater and DRW harbored van genes conditioning phenotypic resistance to vancomycin, the highest percentage of vancomycin-resistant strains (57.0%), mostly strains harboring vanC1 genes (27.6%), was noted in TWW. More than 65.0% of the isolated strains had different virulence genes, the highest number of isolates were positive for cell wall adhesin efaA and sex pheromones cob, cpd, and ccf which participate in the induction of virulence. Many of the strains isolated from TWW were resistant to a higher number of drugs and were more virulent than those isolated from UWW and HWW. The enterococci isolated from DRW and wastewater were characterized by similar multidrug resistance and virulence profiles, and significant correlations were observed between these groups of isolates. These findings suggest that pathogenic enterococci are released with TWW and can spread in the river, pose a serious epidemiological threat and a risk to public health.

Characterization of enterococcal urinary tract infections, with special reference to High Level Aminoglycoside Resistance (HLGR)

Background: Multidrug-resistant Enterococci are major problem and are increasingly reported worldwide. Enterococci have converted over the years from a normal gut commensal to opportunistic nosocomial as well as community acquired pathogen. High level resistance to Aminoglycosides and concomitant resistance to Vancomycin reduces the treatment options and complicated the management of serious infections caused by Enterococci. Methods and materials: A retrospective analysis was conducted in the Department of Microbiology, SGPGI for a period of 10 months from Jan 2018 to October 2018. Enterococcus isolated from urine colony counts of ≥10 5 colony-forming units per ml (CFU/ml) were included in the study. Identification was performed by MALDI TOF and Antimicrobial susceptibility testing was performed by the VITEK 2.0 in accordance to CLSI guidelines. Results: In the study, 186 Enterococci spp. were isolated out of which 159/186 (85.48%) were E.faecalis and 27/186 (14.51%) were E.faecium. High Level Aminoglycoside resistance (HLG) was seen in 67/186 (36.02%) of which E.faecalis comprised of 43/67 (64.17%). Three isolates, all identified as E. faecium, were found to be resistant to High level Gentamycin and Vancomycin. Overall, antibiogram of the isolates showed a high resistance to ampicillin, followed by ciprofloxacin, High level Gentamycin (36.02%), High level Streptomycin (36.02%), vancomycin (1.61%), teicoplanin (1.61%), linezolid (1.61%) and nitrofurantoin (1%). A subset of E.faecalis were randomly selected and characterised for HLG resistance genes. DISCUSSION-History of recent hospitalization and the presence of indwelling urinary catheter was associated with VRE and HLGR enterococci infection or colonization. Overall, High-Level Aminoglycoside Resistance (HLAR) was observed more than glycopeptide resistance. Isolates resistant to HLG but susceptible to vancomycin expressed more virulence factors. Conclusion: This study highlights the temporal increase in antimicrobial resistance and in MDR bacteria causing UTI creates important therapeutic limitations. Surveillance strategies need to be upgraded and implemented in order to prevent the emergence and further spread of not only VRE but also HLAR enterococci in the hospital.

Analysis of the occurrence and molecular characteristics of drug-resistant strains of Enterococcus faecalis isolated from the gastrointestinal tract of insectivorous bat species in Poland: A possible essential impact on the spread of drug resistance?

Bats are poorly understood as a reservoir of multidrug-resistant strains; therefore, the aim of this study was to determine molecular characterization of multidrug-resistant Enterococcus strains isolated from bat species from Poland. A multi-stage analysis based on targeted isolation of drug-resistant strains (selective media with tetracycline, chloramphenicol, gentamicin, streptomycin, and vancomycin), determination of the phenotypic profile of drug-susceptibility using the disc diffusion method, and amplification of DNA fragments surrounding rare restriction sites (ADSRRS-fingerprinting) was used for the isolation and differentiation of strains. The applied strategy finally allowed identification of E.faecalis resistant to at least one antimicrobial in 47.2% of the single-animal group and in 46.9% of the pooled samples of bat's guano. Out of the 36 distinct isolates, 69% met the criteria of multi-drug resistance, with a dominant combination of resistance to tetracycline, erythromycin, and rifampicin. Simultaneously, 41.6% of the strains were high-level aminoglycoside resistant (HLAR). In most strains, phenotypic resistance was reflected in the presence of at least one gene encoding resistance to a given drug. Moreover, our research results show that some genes were detected simultaneously in the same strain statistically significantly more frequently. This may confirm that the spread of some genes (tetM and ermB or aph (3')-IIIa as well as gelE and aac (6')-Ie-aph (2″)-Ia or ant (6)-Ia) is associated with their common occurrence on the same mobile genetic element. To our knowledge, this is the first analysis of multidrug-resistance among E.faecalis isolated from bats. Our research demonstrates that the One Health concept is not associated exclusively with food-producing animals and humans, but other species of wildlife animals should be covered by monitoring programs as well. We confirmed for the first time that bats are an important reservoir of multi-resistant E.faecalis strains and could have a great impact on environmental resistance.

Evaluation of the antibacterial and anticancer activities of marine Bacillus subtilis ESRAA3010 against different multidrug resistant Enterococci (MDRE) and cancer cell lines

Fifty nine isolates belonging to six species of Enterococci namely, Enterococcus faecalis, Enterococcus faecium, Enterococcus raffinosus, Enterococcus durans, Enterococcus mundtiiand Enterococcus avium (n = 35, 15, 4, 3, 1 and 1 isolates, respectively) were obtained from different clinical specimens including urine, pus, blood, wound, sputum and synovial fluid. The highest numbers of Enterococci were recorded from the pus (20 isolates, 33.90%) followed by urine (12 isolates, 20.34%) while the lowest frequency was observed with synovial fluid samples (2 isolates, 3.39%). These isolates showed different multidrug resistant patterns with the lowest resistant for linezolid (n = 5, 8.48%), followed by teicoplanin (n = 14, 23.73%) and vancomycin (n = 20, 33.90%) while they exhibited the highest resistant against penicillin (n = 53, 89.83%), oxacillin (n = 50, 84.75%), erythromycin (n = 49, 83.05%) and streptomycin (n = 47, 79.66 %). On the other hand, a free living marine bacterium under isolation code ESRAA3010 was isolated from seawater samples obtained from the fishing area Masturah, Red Sea, Jeddah, Saudi Arabia. The phenotypic, chemotaxonomic, 16S rRNA gene analyses and phylogenetic data proved that isolate ESRAA3010 is very close to Bacillus subtilis and then it was designated as Bacillus subtilis ESRAA3010. It gave the highest antagonistic activity against all clinical Enterococcus faecalis, Enterococcus faecium, Enterococcus raffinosus, Enterococcus durans, Enterococcus mundtiiand Enterococcus avium isolates under study with minimum inhibitory concentration (MIC) ranged from 4 to 56 µg/mL, 4 to 12 µg/mL, 4 to 8 µg/mL, 4 to 8 µg/mL, 8 µg/mL and 4 µg/mL, respectively as well as minimum bactericidal concentration (MBC) (8 to 64 µg/mL, 4 to 16 µg/mL, 4 to 12 µg/mL, 4 to 16 µg/mL, 12 µg/mL and 8 µg/mL, respectively). Moreover it showed anti-proliferative activity against colon (HCT-116), liver (HepG-2), breast (MCF-7) and lung (A-549) carcinomas with IC50 equal to 39, 50, 75 and 19 µg/mL, respectively which indicates its prospective usage in the upcoming decades.

Spotlight on the Selected New Antimicrobial Innate Immune Peptides Discovered During 2015-2019

Antibiotic resistance is a global issue and new anti-microbials are required. Anti-microbial peptides are important players of host innate immune systems that prevent infections. Due to their ability to eliminate drug-resistant pathogens, AMPs are promising candidates for developing the next generation of anti-microbials. The anti-microbial peptide database provides a useful tool for searching, predicting, and designing new AMPs. In the period from 2015-2019, ~500 new natural peptides have been registered. This article highlights a selected set of new AMP members with interesting properties. Teixobactin is a cell wall inhibiting peptide antibiotic, while darobactin inhibits a chaperone and translocator for outer membrane proteins. Remarkably, cOB1, a sex pheromone from commensal enterococci, restricts the growth of multidrug-resistant Enterococcus faecalis in the gut at a picomolar concentration. A novel proline-rich AMP has been found in the plant Brassica napus. A shrimp peptide MjPen- II comprises three different sequence domains: serine-rich, proline-rich, and cysteine-rich regions. Surprisingly, an amphibian peptide urumin specifically inhibits H1 hemagglutinin-bearing influenza A virus. Defensins are abundant and typically consist of three pairs of intramolecular disulfide bonds. However, rat rattusin dimerizes via forming five pairs of intermolecular disulfide bonds. While human LL-37 can be induced by vitamin D, vitamin A induces the expression of resistin-like molecule alpha (RELMα) in mice. The isolation and characterization of an alternative human cathelicidin peptide, TLN-58, substantiates the concept of one gene multiple peptides. The involvement of a fly AMP nemuri in sleep induction may promote the research on the relationship between sleep and infection control. The functional roles of AMPs continue to grow and the general term "innate immune peptides" becomes useful. These discoveries widen our view on the anti-microbial peptides and may open new opportunities for developing novel peptide therapeutics for different applications.

Phenotypic and Molecular Characterization of Plasmid-Mediated Virulence and Antimicrobial Resistance Traits among Multidrug Resistant Enterococcus spp. in Egypt

Enterococcus spp. are remarkable multidrug resistant (MDR) bacteria that are causing serious healthcare-associated infections. The current study investigated the frequency of Enterococcus spp., antimicrobial susceptibility, biofilm formation and the presence of some plasmid-mediated virulence characters and antimicrobial resistance determinants in enterococcal isolates from Egyptian hospitals in Cairo. Enterococcus bacterial isolates were recovered from different clinical specimens and identified using biochemical testing and KB005A HiStrep™ identification kit. Kirby-Bauer disc diffusion method and/or broth microdilution method were used to determine the antimicrobial susceptibility patterns. Phenotypic assays were performed to study biofilm formation and cytolysin and gelatinase production. PCR assays targeting the plasmid-carried genes aac(6’)-aph(2’), aph(3)-IIIa, vanA, agg and cylA were performed. In this study, 50 isolates of diverse Enterococcus spp. were identified with E. faecium was the most frequently isolated one. High resistance profiles were determined against tested antimicrobials and all isolates were MDR. Moderate biofilm formation was detected in 20% of isolates, 18% showed complete blood hemolysis and 12% produced gelatinase. All isolates carried the tested aminoglycosides resistance genes, while vanA was found only in 4 isolates (8%). The virulence genes agg and cylA were detected in 4% and 32% of isolates, respectively. In conclusion, E. faecium was the most prevalent species. The entire isolates set were MDR and the plasmid-carried aminoglycoside resistance genes were extensively disseminated among MDR isolates. Thus, regular surveillance studies, from the area of study or other geographical regions in Egypt, and strict infection control measures are required to monitor the emerging MDR enterococci.

Antimicrobial Resistance Gene Detection and Plasmid Typing Among Multidrug Resistant Enterococci Isolated from Freshwater Environment.

In this study, mechanisms of antimicrobial resistance (AR) as well as the abundance and diversity of plasmids were determined among multidrug resistant (MDR) enterococci from surface water in GA, USA. A total of 51 enterococci isolates were screened for the presence of 27 AR genes conferring resistance to ciprofloxacin, erythromycin, tylosin, kanamycin, streptomycin, lincomycin, Quinupristin/Dalfopristin (Q/D), and tetracycline. A plasmid classification system based on replication genes was used to detect 19 defined Gram-positive plasmid replicon families. Twelve genes were identified as conferring resistance to erythromycin and tylosin (erm(B) and erm(C)), kanamycin (aph(3′)-IIIa), streptomycin (ant(6)-Ia), lincomycin (lnu(B)), Q/D (vat(E)), ciprofloxacin (qnrE. faecalis), and tetracycline (tet(K), tet(L), tet(M), tet(O) and tet(S)). Twelve different rep-families were identified in two-thirds of the isolates. While AR genes commonly found in human and animals were detected in this study among environmental enterococci, resistance genes could not be determined for many of the isolates, which indicates that diverse AR mechanisms exist among enterococci, and the understanding of AR mechanisms for environmental enterococci is limited. Diverse rep-families were identified among the enterococci recovered from the aquatic environment, and these rep-families appear to be quite different from those recovered from other sources. This work expands knowledge of AR gene reservoirs and enterococcal plasmids across a wider range of environments.

Multidrug Resistant Organisms (MDRO) in Rehabilitation: Prevalence and Risk Factors for MRGN and VRE

After a first large-scale study on multi-drug resistant organisms (MDRO) in rehabilitation facilities in 2014, the Rhine-Main network on MDRO carried out another investigation in 2019. With regard to the recently published KRINKO recommendations on multidrug resistant enterococci, now vancomycin -resistant enterococci (VRE) and multi-drug resistant gram-negative pathogens (3MRGN and 4MRGN, i. e. gramnegative organisms resistant against 3 resp. 4 groups of antiinfectiva) were investigated. A total of 16 hospitals took part, including one clinic for early neurological rehabilitation (ENR). Patient participation was voluntary. Rectal swabs were analyzed in a medical-microbiological laboratory (certified according to DIN ISO 15189) using standard methods (including MALDI-TOF-MS and VITEK 2 resistance testing according to EUCAST). By using the standardized questionnaire of the Europe-wide HALT examination (healthcare associated infections in long-term care facilities), patient characteristics (age, gender, hospital, surgical and MDRO medical history, Medical devices, current antibiotic therapy etc.) were collected. 928 patients took part in the study, 895 from general rehabilitation facilities (GR) and 33 from early neurological rehabilitation (ENR). 65% of GR patients (ENR 100%) had been hospitalized in the previous 6 months, 29% (ENR 100%) of the patients had been admitted directly from a hospital, 22% (ENR 64%) had received antibiotic therapy in the last 3 months. Medical devices were rarely used in GR patients with 1% overall, but often in the ENR with 61% urinary catheters and 36% vascular catheters. 2.2% (ENR 33.3%) of GR patients were colonized with VRE and 6.7% (ENR 18.2%) with 3MRGN; one patient exhibited a 4MRGN (ENR 0). Compared to our previous study, there were no significant changes in the patient characteristics. The VRE prevalence was low at 3.3%, the prevalence of 3MRGN was higher compared to 2014 (7.1% vs. 3.6%). Risk factors for VRE and 3MRGN colonization (significant increased odds ratio) were: history of hospital treatment and an increased need for care due to restricted mobility, incontinence and disorientation. In addition, previous antibiotic treatment and skin barrier injuries due to Medical devices or wounds were detected as further risk factors for VRE colonization.

Antimicrobial Resistance, Virulence Genes, and Biofilm Formation Capacity Among Enterococcus species From Yaks in Aba Tibetan Autonomous Prefecture, China

Yaks provide necessities such as meat and milk for Tibetans living at high altitudes on and around the Qinghai-Tibetan Plateau. Enterococci are ubiquitous members of the animal gut microbiota that can cause biofilm-associated opportunistic infections. Meanwhile, multidrug-resistant Enterococcus also poses a serious threat to public health. This study aims to characterize antibiotic resistance, virulence genes, and biofilm formation of enterococci from yaks. From April 2018 to July 2019, we collected 395 fecal samples of yaks in Aba Tibetan Autonomous Prefecture, China. Enterococci isolated from the samples were identified and classified according to the 16S rDNA sequence. The antibiotic resistance of each isolate was detected according to the Kirby-Bauer disk diffusion method, and antibiotic resistance genes were detected by polymerase chain reaction (PCR) and sequencing. Enterococcal biofilms were assessed using standard procedures. Different virulence genes were detected by PCR and sequencing. In total, 381 enterococci strains were recovered, with Enterococcus faecalis (41.99%) and Enterococcus faecium (37.80%) being the predominant species. Many isolates were multidrug- resistant (60.37%) and showed a high resistance rate to rifampicin (64.30%) and tetracycline (61.54%). We also detected various antimicrobial resistance (AMR) genes in the tested strains. The E. faecalis strains had higher frequency of biofilm formation and virulence genes than other enterococcal species. This is the first report that shows yaks are repositories for drug-resistant enterococci with virulent determinants and biofilms that may spread into humans and to environment. This study also provides useful data suggesting that enterococci may pose a potential health risk to yaks. Therefore, active surveillance of AMR and pathogenesis in enterococci from yaks is urgently warranted.