Enterococcal Isolates Research Articles

Prevalence of Class 1 Integron and In Vitro Effect of Antibiotic Combinations of Multidrug-Resistant Enterococcus Species Recovered from the Aquatic Environment in the Eastern Cape Province, South Africa.

Enterococci are regarded as a better indication of faecal pollution in freshwater and marine waters. Their levels in seawater are positively connected with swimming-related gastrointestinal disorders. This study used an Enterococcus-specific polymerase chain reaction (PCR) to characterize the isolates. Classes 1 and 2 integrons were examined for environmental Enterococcus isolates using a standard biological procedure. All strains were assessed against a panel of 12 antibiotics from various classes using disc diffusion methods. The microdilution method was used to work out the minimum inhibitory concentration (MIC) according to the CLSI guiding principles. The combination therapy of the resistant drugs was evaluated using a checkerboard assay and a time-dependent test for assessing their bactericidal or bacteriostatic activity. The gene diversity of the tested organisms was analyzed with the aid of Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR. In total, 57 Enterococcus spp. environmental samples were recovered, in which Enterococcus faecalis (33.33%) and Enterococcus faecium (59.65%) were the dominant species. Resistance to linezolid, ciprofloxacin, erythromycin, gentamicin, vancomycin, rifampicin, and tetracycline was prevalent. Fifty (50) strains tested positive for class 1 integron, more frequent in Enterococcus faecium and Enterococcus faecalis isolates, with no gene cassette array discovered. A combination of gentamicin (MIC 4 µg/mL) with vancomycin (MIC 256 µg/mL) antibiotics against Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin (1 µg/mL) with Ampicillin (16 µg/mL) antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The ERIC-PCR analysis pointed out that most of the assessed isolates have close genetic similarities.

Occurrence, antibiogram, high-level vancomycin and aminoglycosides resistance and potential virulence factors of enterococci in dogs in Nigeria

AbstractThis study was conducted to isolate enterococci from dogs in Nigeria, and to determine the potential virulence, antibiotic susceptibility, phenotypic vancomycin (VAN), high-level ampicillin (AMP) and aminoglycosides susceptibility profile of the isolates. Rectal swabs were collected from 295 randomly-selected, clinically-healthy dogs. The isolation of enterococci was done using Slanetz and Bartley enterococcal selective medium. The resistance of 150 non-repetitive isolates was determined using disc diffusion method. VAN resistance was assessed by high-level disc diffusion and agar-screening methods. High-level AMP and aminoglycosides (gentamicin and streptomycin) resistance was determined by agar-screening method. Potential virulence factors were assayed using phenotypic methods. Out of 295 samples, 234 (80.7%) gave positive growth. From these, 250 enterococcal isolates comprised 229 (91.6%) non-pigmented and 21 (8.4%) pigmented strains, were obtained. Resistance of the isolates was 89% to erythromycin, 92% to rifampicin, 77% to chloramphenicol, 83% to tetracycline, 64% to ciprofloxacin, 32.7% to VAN, 24.7% to high-level streptomycin (HLS) and 6% to high-level gentamicin (HLG). Among 150 non-repetitive resistant isolates, 144 (96%), including all the VAN-, HLS- and HLG-resistant strains, exhibited resistance to at least 3 classes of antibiotics. The mean multiple antibiotic resistance index was 0.54 (range = 0.22 – 0.89). Of these 150 isolates, 94 (62.7%), including all the VAN-, HLS- and HLG-resistant strains, displayed virulence potentials as biofilm (44.7%), surface-layer (13.8%), haemolysin (21.3%), gelatinase (40.4%), caesinase (10.6%) and deoxyribonuclease (12.8%) activities. This study showed that dogs in Nigeria are potential reservoirs and disseminators of potentially-virulent, multidrug-, VAN- and high-level aminoglycosides-resistant enterococci.

Antimicrobial resistance characteristics and phylogenetic relationships of pleuromutilin-resistant Enterococcus isolates from different environmental samples along a laying hen production chain

Antimicrobial resistance in the laying hen production industry has become a serious public health problem. The antimicrobial resistance and phylogenetic relationships of the common conditional pathogen Enterococcus along the laying hen production chain have not been systematically clarified. 105 Enterococcus isolates were obtained from 115 environmental samples (air, dust, feces, flies, sewage, and soil) collected along the laying hen production chain (breeding chicken, chick, young chicken, and commercial laying hen). These Enterococcus isolates exhibited resistance to some clinically relevant antibiotics, such as tetracycline (92.4%), streptomycin (92.4%), and erythromycin (91.4%), and all strains had multidrug resistance phenotypes. Whole genome sequencing characterized 29 acquired antibiotic resistance genes (ARGs) that conferred resistance to 11 classes of antibiotics in 51 pleuromutilin-resistant Enterococcus isolates, and lsa(E), which mediates resistance to pleuromutilins, always co-occurred with lnu(B). Alignments with the Mobile Genetic Elements database identified four transposons (Tn554, Tn558, Tn6261, and Tn6674) with several ARGs (erm(A), ant(9)-la, fex(A), and optrA) that mediated resistance to many clinically important antibiotics. Moreover, we identified two new transposons that carried ARGs in the Tn554 family designated as Tn7508 and Tn7492. A complementary approach based on conventional multi-locus sequence typing and whole genome single nucleotide polymorphism analysis showed that phylogenetically related pleuromutilin-resistant Enterococcus isolates were widely distributed in various environments on different production farms. Our results indicate that environmental contamination by antimicrobial-resistant Enterococcus requires greater attention, and they highlight the risk of pleuromutilin-resistant Enterococcus and ARGs disseminating along the laying hen production chain, thereby warranting effective disinfection.

Probiotic Potential of the Marine Isolate Enterococcus faecium EA9 and In Vivo Evaluation of Its Antisepsis Action in Rats.

This study aims to obtain a novel probiotic strain adapted to marine habitats and to assess its antisepsis properties using a cecal ligation and puncture (CLP) model in rodents. The marine Enterococcus faecium EA9 was isolated from marine shrimp samples and evaluated for probiotic potential after phenotypical and molecular identification. In septic animals, hepatic and renal tissues were histologically and biochemically evaluated for inflammation and oxidative stress following the probiotic treatment. Moreover, gene expressions of multiple signaling cascades were determined using RT-PCR. EA9 was identified and genotyped as Enterococcus faecium with a 99.88% identity. EA9 did not exhibit any signs of hemolysis and survived at low pH and elevated concentrations of bile salts. Moreover, EA9 isolate had antibacterial activity against different pathogenic bacteria and could thrive in 6.5% NaCl. Septic animals treated with EA9 had improved liver and kidney functions, lower inflammatory and lipid peroxidation biomarkers, and enhanced antioxidant enzymes. The CLP-induced necrotic histological changes and altered gene expressions of IL-10, IL-1β, INF-γ, COX-2, SOD-1, SOD-2, HO-1, AKT, mTOR, iNOS, and STAT-3 were abolished by the EA9 probiotic in septic animals. The isolate Enterococcus faecium EA9 represents a promising marine probiotic. The in vivo antisepsis testing of EA9 highlighted its potential and effective therapeutic approach.

Enterococcal pyogenic liver abscesses: high risk of treatment failure and mortality

Enterococci are the most frequent gram-positive bacteria recovered from pyogenic liver abscesses (PLA). This study aims to analyze the impact of the presence of Enterococcus spp. on PLA outcome. We retrospectively analyzed the characteristics and outcome of all PLA cases in which Enterococcus spp. was isolated between January 2010 and September 2019 in a French university hospital and compared them to PLA without Enterococcus spp. Enterococci were recovered from 68 of the 359 (19%) PLA cases. Among the 78 isolates, Enterococcus faecalis (n = 37, 47.7%) and Enterococcus faecium (n = 32, 41%) were the most frequent. Enterococcal PLA were more often of biliary origin (79.4% versus 54.6%, p < 0.001) or post-surgical (35.3% versus 18.6%, p = 0.004). Multivariate analysis showed an independent association between the isolation of Enterococcus spp. and 3-month mortality (HR 2.51, p = 0.011), primary failure (HR 2.15, p = 0.006), but not with relapses (HR 0.86, p = 0.739). In the subgroup of enterococcal PLA, portal vein thrombosis was the only factor significantly associated with 3-month mortality (univariate HR 3.45, p = 0.023) or primary treatment failure (multivariate, HR 4.02, p = 0.006). Enterococcus spp. identification in a PLA is associated with a higher mortality and primary treatment failure.

A Study on Glycopeptide-Resistant Genotypes among Clinical Isolates of Enterococcus with Van B Phenotype.

Enterococci, although remarked as harmless commensals of the intestinal tract of humans and animals, have become a significant source of infection in hospitalized patients worldwide.The present study aimed to isolate and identify enterococci from clinical samples and to determine the genotypic characteristics of vancomycin-resistant enterococcus isolates. A total of 774 isolates of enterococci from clinical samples were identified to the species level, and their anti-microbial susceptibility pattern was determined by Kirby Bauer Disk Diffusion method and Vitek 2 automated system. Screening for vancomycin resistance was performed by using brain heart infusion agar containing 6 micrograms/ml of vancomycin. The minimum inhibitory concentration (MIC) of vancomycin was determined by the agar dilution method and Epsilometer test (E test). Genotyping was carried out for resistant isolates by multiplex polymerase chain reaction. Thirty (3.88%) isolates were resistant to vancomycin by agar screen method. Five isolates showed intermediate resistance with anMIC of 8-16 micrograms/ml for vancomycin by agar dilution. By the E test, two isolates displayed an MIC of ≥32 micrograms/ml for vancomycin and one isolate showed an MICof ≥32 micrograms/ml for teicoplanin.Van A was the common genotype isolated. The present study reports isolates of Enterococcus faecalis with a susceptible MIC for glycopeptide and the presence of the Van A gene. Heterogeneous resistance among clinical isolates of Enterococcus faecalis was observed in our study. The predominant phenotype and genotype detected among clinical isolates were Van A.

Detection of Genes Related to Linezolid Resistance (poxtA, cfr, and optrA) in Clinical Isolates of Enterococcus spp. from Humans: A First Report from Iran.

Enterococci may develop resistance to linezolid through chromosomal mutations that involve specific linezolid resistance genes, such as cfr, optrA, and poxtA. The objective of this study was to evaluate the antibiotic susceptibility of enterococcal isolates and identify cfr, optrA, and poxtA genes in MDR isolates. Enterococcal isolates were collected from various clinical specimens at Al-Zahra, Amin, and Khorshid Hospitals in Isfahan. The Enterococcus isolates were identified as belonging to the E. faecalis and E. faecium species by using specific gene (D alanine D alanine ligase ddl) sets in PCR. To detect cfr, optrA, and poxtA genes among the species, a multiplex-PCR assay was performed. Out of 175 isolates, E. faecalis predominated 129/175 (73.7%). Furthermore, the prevalence of vancomycin-resistant Enterococci (VRE) and linezolid-resistant Enterococci (LRE) was 29.7% and 4%, respectively. The overall prevalence of MDR was 91.1%, 68.9%, and 66.6% of E. faecium, E. faecalis, and other Enterococcus spp., respectively. Interestingly, the frequency of optrA (71.4%) in E. faecium and poxtA and crf (42.8%) in E. faecalis were detected among LRE species. A statistically significant relationship (P < 0.05) was found between the presence of the three genes and the occurrence of LRE. This is the first study to report the detection of linezolid resistance genes (cfr, optrA, and poxtA) in clinical Enterococcus spp. isolates from Iran, conducted at Isfahan University of Medical Sciences hospitals. The emergence of enterococcal strains that resist linezolid is concerning as it can lead to the spread of resistant strains among patients, resulting in treatment failure.

Vancomycin Resistant Enterococcal Urinary Tract Infection: A Potential Threat

Introduction: Enterococci are considered less virulent organisms, but have incurred recognition for being notorious for their acquisition and transfer of resistance. The greatest potential threat posed by enterococci is vancomycin resistance. The transfer of enterococcal vancomycin resistance to Staphylococcus aureus has been achieved making scientists apprehensive of its consequences. Aim: To find the prevalence of Vancomycin-Resistant Enterococci (VRE) and to determine the antimicrobial resistance pattern in enterococcal urinary isolates. Materials and Methods: A cross-sectional study was carried out on all urinary samples suspected of Urinary Tract Infection (UTI) received for duration of one year from April 2021 to March 2022 in the Department of Microbiology at Uttar Pradesh University of Medical Sciences, Saifai, Etawah, Uttar Pradesh. Enterococci were isolated and identified with a VITEK-2® COMPACT (bioMérieux) automated system. The antibiotic susceptibility pattern was determined by Kirby-Bauer disc diffusion method. Further, confirmation of VRE was done by Minimum Inhibitory Concentration (MIC) E-test. Results: A total of 128 urinary enterococcal isolates were identified with the male-to-female ratio 1.37:1 and mean age of patients was 37.18±22.64 years. Out of total, 71.87% were identified as Enterococcus faecalis followed by 24.21% Enterococcus faecium and the rare species (4%) including E.durans, E.hirae, E.raffinosus. The prevalence of VRE was found to be 8.6%. Maximum resistance by isolates has been shown against ampicillin, erythromycin, ciprofloxacin, and doxycycline. All isolates were sensitive to linezolid. Nitrofurantoin resistance was observed in 4.34% and 25.80% of E.faecalis and E.faecium isolates respectively. Conclusion: In this study, it was revealed that the emergence of VRE in urinary isolates with antimicrobial resistance was higher among E. faecium. All this puts pressure on strict compliance with a multidimensional approach with collaboration of antibiotic stewardship, educational and surveillance programs.

Vancomycin-variable enterococci in sheep and cattle isolates and whole-genome sequencing analysis of isolates harboring vanM and vanB genes.

Vancomycin resistance encoded by the vanA/B/M genes in enterococci is clinically important because of the transmission of these genes between bacteria. While vancomycin resistance is determined by detecting only vanA and vanB genes by routine analyses, failure to detect vanM resistance causes vancomycin resistance to be overlooked, and clinically appropriate treatment cannot be provided. The study aimed to examine the presence of vanM-positive enterococcal isolates in Ankara, Turkey, and to have detailed information about them with sequence analyses. Caecal samples were collected from sheep and cattle during slaughter at different slaughterhouses in Ankara, Turkey. Enterococci isolates were identified, confirmed, and analyzed for the presence of vanA/B/M genes. Antibiotic resistance profiles of isolates were determined by the broth microdilution method. A whole genome sequence analysis of the isolates harboring the vanM and vanB genes was performed. 13.7% of enterococcal isolates were determined as Enterococcus faecium and Enterococcus faecalis. 15% of these isolates contained vanB, and 40% were vanM-positive. S98b and C32 isolates were determined to contain 16 CRISPR-Cas elements. 80% of the enterococci isolates were resistant to nitrofurantoin and 15% to ciprofloxacin. The first vanM-positive vancomycin-variable enterococci (VVE) isolates from food-producing animals were identified, and the S98b strain has been assigned to Genbank with the accession number CP104083.1. Therefore, new studies are needed to facilitate the identification of vanM-resistant enterococci and VVE strains.

Discovery of benzoxazole-thiazolidinone hybrids as promising antibacterial agents against Staphylococcus aureus and Enterococcus species.

Antibiotic resistance is rapidly exacerbating the unceasing rise in nosocomial infections caused by drug-resistant bacterial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacteriaceae (CRE) and vancomycin-resistant Enterococcus (VRE). Therefore, there is a dire need for new therapeutic agents that can mitigate the unbridled emergence of drug-resistant pathogens. In the present study, several benzoxazole-thiazolidinone hybrids (BT hybrids) were synthesized and evaluated for their antibacterial activity against the ESKAP pathogen panel. The preliminary screening revealed the selective and potent inhibitory activity of hydroxy BT hybrids against S. aureus with MIC ≤ 4 μg mL-1. Hydroxy compounds (BT25, BT26, BT18, BT12, and BT11) exhibited a good selectivity index (SI > 20), which were determined to be non-toxic to Vero cells. An engaging fact is that two compounds BT25 and BT26 showed potent activity against various clinically-relevant and highly drug resistant S. aureus (MRSA & VRSA) and Enterococcus (VRE) isolates. These hybrids showed concentration-dependent bactericidal activity that is comparable to vancomycin. These experimental results were corroborated with docking, molecular dynamics, and free energy studies to discern the antibacterial mechanisms of hydroxy BT hybrids with three bacterial enzymes DNA gyrase B, MurB, and penicillin binding protein 4 (PBP4). The reassuring outcome of the current investigation confirmed that the aforementioned BT hybrids could be used as very promisingly potent antibacterial agents for the treatment of Staphylococcus aureus and Enterococcus infections.

Occurrence of Vancomycin Resistant Enterococcus faecalis in Chicken Flocks

The current study aimed to determine the occurrence and antibiotic resistance pattern profile of some Enterococcus isolates recovered from chicken flocks as well as detection of vanA gene representative for vancomycin resistant enterococci. A total of 150 cloacal swabs were collected from chicken flocks including broilers and layers flocks (75 samples per each) from apparently healthy birds. The obtained results clarified that the overall isolation rate of enterococci in examined chicken flocks was 17.3% (20 isolates out of 150 cloacal swabs) and the isolation rates were 9.33 and 17.33% in broilers and layers flocks, respectively. Antimicrobial susceptibility testing was performed against 8 antibiotics discs using disk diffusion method. Results of molecular characterization of 20 Enterococcus isolates recovered from chicken samples showed that all isolates were positive for presence of Enterococcus 16S rRNA and E. faecalis 16S rRNA, while only 8 isolates were positive for presence of vanA gene representative for vancomycin resistant enterococci.

Влияние различных концентраций глюкозы на синтез молочной кислоты бактериями рода Enterococcus

In the present work, we investigated the effect of glucose concentration in the nutrient medium on the growth of bacterial isolates Enterococcus faecium and Enterococcus sp. from wheat bran, degraded by the action of native microbiota for various periods of time, and lactic acid biosynthesis. The cultures were identified by sequencing the 16S rRNA gene. Cultivation was carried out in a shaker incubator for 50 hours. The kinetics of bacterial growth was evaluated by measuring the optical density of the culture fluid at a wavelength of 600 nm; the lactic acid content was determined by photometric method using iron (III) chloride. Glucose and yeast extract, as well as beet molasses, were used as components of the culture medium for cultivation. It is shown that the maximum optical density characterizing the accumulation of biomass and the lactic acid content for both strains were achieved with a minimum concentration of glucose in the nutrient medium (50 g/l). These observations indicate a low resistance of the studied bacteria to elevated concentrations of glucose in the medium. Glucose concentrations of 100 g/l and above inhibited biomass growth and lactic acid synthesis. The revealed effect allowed us to make an assumption about the belonging of bacterial isolates to oligocarbophiles. When culturing a bacterial culture of E. sp., the highest yield (11.65 g/l) of lactic acid was achieved in comparison with E. faecium. It has been shown that when the glucose content in the culture medium is 50 g/l, the conversion rate of the substrate to lactate reaches 23.3%. When culturing the studied bacterial isolates on a medium containing beet molasses as a carbon source, the lactate yield was 23 g/l for the E. faecium strain and 22 g/l for E. sp. (the degree of carbohydrate conversion to MK is 46% and 44%, respectively). The high content of simple carbohydrates in molasses contributes to an increase in the productivity of biomass for the biosynthesis of lactic acid.

Determination Of Enterococcus Species And Antibiotic Resistance In Budgerigars

Abstract: In this study, it was aimed to determine the resistance profile by examining the prevalence and species distribution of enterococci in rectal samples of healthy budgerigars and their susceptibility to antibiotics. 100 cloacal swab samples were used in the study. Identification and antibiotic resistance of Enterococcal isolates obtained by classical methods were determined with the automated identification system. As a result of the study, 22 (75.86%) E. faecalis, 2 (6.90%) E. faecium (6.90%) E. hirae (6.90%) and E. casseliflavus/gallinarum and 1 S. uberis (3.44%) was obtained. The presence of Enterococci was detected in 29% of the samples. In general, they were suspectible to Amoxicillin clavunate (96.4%), Ampicillin (100%), Ciproflaxacin (54.2%), Levoflaxacin (60.9%), Gentamicin(Syn) (82.1%), Streptomycin(Syn) (28.6%), Tigecycline (80%), Vancomycin(89.3%), Teicoplanin (96.4%), Linezolide (96.4%) and Nitrofurontion (100%), and they showed 100% resistance to Cefocitin, Amikacin, Gentamicin, Tobramycin, Clindamycin, Erythromycin, TMP-SXT, Fusidic acid and Quinopuristin-Dalfopuristin. The presence of Entrococcal species, which are very important in terms of zoonosis, in healthy budgerigars was revealed. In addition, the different types of antibiotic resistance found in the studies also reveal the necessity of performing antibiotic susceptibility tests in this type of infections. However, it has been demonstrated that which antibiotics will be effective in nosocomial and/or gastrointestinal infections of Enterococcal origin in budgerigars.

Antibiotic Resistance and Biofilm Formation in Enterococcus spp. Isolated from Urinary Tract Infections.

Background: A urinary tract infection (UTI) resulting from multidrug-resistant (MDR) enterococci is a common disease with few therapeutic options. About 15% of urinary tract infections are caused by biofilm-producing Enterococcus spp. Therefore, the objective of this study was to identify the MDR enterococci associated with UTIs and assess their potential to produce biofilms. Methods: Thirty Enterococcus isolates were obtained from urine samples collected from UTI patients at King Abdulaziz Specialist Hospital in Taif, Saudi Arabia. The antimicrobial resistance profiles of the isolates were evaluated using disk diffusion techniques against 15 antimicrobial agents. Two techniques, Congo red agar (CRA) and a microtiter plate (MTP), were used to assess the potential of the isolates to produce biofilms. The enterococcal isolates were screened for biofilm-related genes, esp; ebpA; and ebpB, using the PCR method. Results: The molecular identification of the collected bacteria revealed the presence of 73.3% Enterococcus faecalis and 26.6% Enterococcus faecium. The antibiotic susceptibility test revealed that all the tested Enterococcus spp. were resistant to all antimicrobials except for linezolid and tigecycline. Additionally, by employing the CRA and MTP techniques, 76.6% and 100% of the Enterococcus isolates were able to generate biofilms, respectively. In terms of the association between the antibiotic resistance and biofilm’s formation, it was observed that isolates capable of creating strong biofilms were extremely resistant to most of the antibiotics tested. The obtained data showed that all the tested isolates had biofilm-encoding genes. Conclusions: Our research revealed that the biofilm-producing enterococci bacteria that causes urinary tract infections were resistant to antibiotics. Therefore, it is necessary to seek other pharmacological treatments if antibiotic medicine fails.

Evaluation of errors during susceptibility reporting of glycopeptide antibiotics for enterococcal isolates on sole basis of widely used disk diffusion test

In resource limited settings, very often susceptibility reports glycopeptide antibiotics are released only on the basis of disk diffusion test. Determination of MIC by either E-strips or microbroth dilution tests can be of paramount importance in checking the errors that may have incurred with the singular use of disk diffusion tests. Distribution of errors in Vancomycin and Teicoplanin susceptibility reporting by disk diffusion test was evaluated in comparison with MIC determination with reference method of E-strip. A total of 40 isolates of Enterococcus species were obtained during the study period. In vancomycin susceptibility reporting, very major errors, major errors and minor errors were observed in 33.3%, 5.4% and 5% instances respectively. For teicoplanin, major errors were observed in 5.3% of instances. E test can be used in conjunction with disk diffusion where resources are limited. We have observed that by using a combination of both disk diffusion and MIC determination by E-strip methods for glycopeptide antibiotics, a majority of reporting errors can be addressed.

Gluten Degradation by the Gut Microbiota of Ulcerative Colitis Patients.

Several studies have reported improved disease symptomatology in ulcerative colitis (UC) patients consuming a gluten free diet. This observation coupled with diversity depletion in the gut microbiota of UC patients led us to hypothesize that UC-associated enteric microbes differentially metabolize dietary gluten to produce immunogenic products that promote inflammation. Gluten concentration in stool was determined using gluten-specific ELISA, and gluten intake was assessed by food frequency questionnaire (FFQ) in UC (n = 12) and healthy controls (HC; n = 13). Gluten-metabolizing bacteria were isolated on minimal media supplemented with 1% gluten from UC and HC and identified by 16S rRNA profiling. Cell-free culture media from gluten metabolizing gut bacterial isolates was assessed for immunogenicity in vitro using HT29 colonocytes. Compared to HC, UC patients did not consume gluten differently (Mann-Whitney; p &gt; 0.10) and exhibited equivalent levels of gluten in their feces (Mann-Whitney; p = 0.163). The profile of gluten-degrading bacteria isolated from UC stool was distinct (Chi-square; p ≤ 0.0001). Compared with Enterococcus isolates, products of gluten degradation by Bacillus strains induced higher IL8 and lower occludin (Mann-Whitney; p = 0.002 and p = 0.059, respectively) gene expression in colonocytes irrespective of whether they originated from UC or healthy gut. Members of HC and UC microbiota exhibit gluten-degrading ability, metabolites of which influence genes involved in inflammation and barrier function in enteric colonocyte cultures. Preliminary findings of this study warrant further investigations into the mechanisms by which gut microbiota contribute to UC pathogenesis through gluten degradation.

1521. Non-faecium Non-faecalis enterococcal bloodstream infections in patients with cancer

Abstract Background Non-E. faecium non-E. faecalis (NFF) enterococci are a heterogeneous group of organisms consisting of enterococci with intrinsic low-level vancomycin resistance as well as several other species known to infect humans. Patients with cancer are at increased risk for bloodstream infections (BSIs) with NFF enterococci, but their optimal treatment and outcomes have not been extensively described. Methods We conducted a retrospective review of patients (pts) with blood cultures positive for all NFF by searching the microbiology database at a major cancer center in Houston, TX from 2016 to 2021. Patients were included if they were ≥ 18 years old, had ≥ 1 blood culture with NFF enterococci, and had a repeat blood culture within 7 days (d) of the index culture, to permit outcome analysis. Outcomes were a) in-hospital mortality, b) microbiological failure (blood culture clearance &amp;gt;4 d after index culture), and c) recurrence of bacteremia (new positive blood culture &amp;lt; 14 d after eradication). Results Sixty-two unique pts had NFF enterococcal BSI. Patients with hematological malignancy made up 53.2% of the cohort (78% had leukemia). The majority (83%) of solid malignancies were pancreatic, biliary, or intestinal in origin. In the 30 d preceding NFF enterococcal BSI, 79% of pts had exposure to antibiotics. The NFF species isolated were E. gallinarum (50%), E. casseliflavus (30.6%), E. avium (11.3%), E. raffinosus (3.2%), E. hirae (3.2%), and E. durans (1.6%). Only 23.3% of NFF enterococci were susceptible to vancomycin, and 53.8% were susceptible to linezolid. Most (62.9%) pts received combination therapy; the most frequent was daptomycin plus a beta-lactam (33.9%). Bacteremia recurred in 8.1% of pts, 27.4% had in-hospital mortality, and 4.8% had microbiological failure. Conclusion This retrospective review provides preliminary insight into the treatments, and outcomes of cancer pts with NFF enterococcal BSIs. The NFF enterococci isolates in this study had a higher rate of linezolid non-susceptibility than previously reported. Molecular investigation of these NFF enterococcal isolates is needed to elucidate the mechanisms and transmission of antibiotic resistance. Comparison of BSIs caused by NFF enterococci to E. faecium/E. faecalis will provide insight to physicians caring for these pts. Disclosures Cesar A. Arias, MD, PhD, Entasis: Grant/Research Support|MeMed Diagnostics Ltd: Grant/Research Support|Merck: Grant/Research Support.

Various mobile genetic elements carrying optrA in Enterococcus faecium and Enterococcus faecalis isolates from swine within the same farm.

In this study, the distribution of the oxazolidinone/phenicol resistance gene optrA and the mobile genetic elements involved in its dissemination were analysed among enterococcal isolates from a farrow-to-finish swine farm. Enterococcus faecium and Enterococcus faecalis isolates were obtained from all pig production stages in the farm. The optrA-carrying E. faecium and E. faecalis isolates were subjected to PFGE and antimicrobial susceptibility testing. Complete sequences of the genetically unrelated optrA-carrying E. faecium and E. faecalis isolates were determined using Illumina HiSeq and MinION platforms. The optrA gene was present in 12.2% (23/188) of the E. faecium and E. faecalis isolates, most of which originated from nursery and finishing stages. The 23 optrA-positive Enterococcus isolates represented 15 PFGE types. WGS of representative isolates of the 15 PFGE types showed that optrA was carried by diverse genetic elements either located in the chromosomal DNA or on plasmids. A novel optrA-bearing genetic element was identified on two distinct multi-resistance plasmids from E. faecium. Two new hybrid plasmids carrying several resistance genes were found in two E. faecalis isolates. pC25-1-like plasmids and chromosomally integrated Tn6674 and Tn6823-like transposons were prevalent in the remaining Enterococcus isolates. The gene optrA was found in genetically unrelated E. faecium and E. faecalis isolates from the same farm. Analysis of the genetic contexts of optrA suggested that horizontal transfer including different plasmids and transposons played a key role in the dissemination of optrA in this farm.

Antimicrobial effect of silver and gold nanoparticles in combination with linezolid on Enterococcus biofilm.

In the past few years, application of new antimicrobial e.g. nanoparticles (NPs) to treat infection caused by drug-resistant bacteria has increased. This study aimed to determine antimicrobial property of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) in combination with linezolid on Enterococcus biofilm. A total of forty-eight isolates of Enterococcus spp. were collected and confirmed by PCR method. The synthesis of biocompatible AgNPs was performed, then analyzed by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy. We carried out minimum inhibitory concentration (MIC) and biofilm forming capacity of AgNPs and AuNPs with linezolid. Twenty-two E. faecium isolates and twentysix E. faecalis investigated in this study. Strong biofilm formation was seen in 12 (25%) of isolates, and others isolates (75%) formed moderate biofilm. AgNPs and Au-NPs size were 26 nm and 20 nm respectively. The MIC of AgNPs was 23.2 μg/ml, and AuNPs were 92.1 μg/ml and the lowest MIC was obtained 2 μg/ml in linezolid. Biofilm formation inhibitory activity by AuNPs + Linezolide and AgNPs + Linezolide 70 to 80 percent increased in average. The antibiofilm activity of AgNPs and AuNPs increased when both agents were used in combination with linezolid in comparison with each agent alone.

SCREENING OF ANTIBIOTIC RESISTANCE AND VIRULENCE GENES OF ENTEROCOCCUS SPP. STRAINS ISOLATED FROM URFA CHEESE

Enterococcus faecium, E. durans and E. faecalis species were isolated and identified from traditional Urfa cheese samples which were produced from unpasteurized raw milk. The enterococcal load of the cheese samples was between 4.4-5.6 log cfu g−1. High-level tetracycline, streptomycin, erythromycin, gentamycin, and penicillin resistance was determined in the enterococcal isolates. Multiple antibiotic resistance was also determined in E. faecalis (20.4%) and E. faecium (16.3%) strains. 36.7% of the enterococcal isolates were greater than 0.2 MAR index ratio in this study. The gelE and agg2 genes were found in 40 (81.63%) of the enterococcal isolates, whereas the vanB gene was found in 3 (6.12%) of the enterococcal isolates. The results indicate that the consumption of Urfa cheese, which is produced using raw milk, may have public health risk because of its antibiotic resistance characteristics and virulence genes of enterococcal biota.