Isolates Of Enterococcus Species Research Articles

Clinical outcome of ampicillin or ampicillin/sulbactam versus glycopeptides in ampicillin-susceptible Enterococcus faecalis/faecium bacteremia: a 10-year retrospective cohort study

BackgroundGlycopeptides for ampicillin-susceptible Enterococcus faecalis/faecium bacteremia are readily prescribed depending on the severity of the condition. However, there is limited data on the outcomes of glycopeptide use compared to ampicillin-containing regimens for ampicillin-susceptible E. faecalis/faecium bacteremia. From an antibiotic stewardship perspective, it is important to determine whether the use of glycopeptides is associated with improved clinical outcomes in patients with ampicillin-susceptible E. faecalis/faecium bacteremia.MethodsThis retrospective cohort study was conducted at a university-affiliated hospital between January 2010 and September 2019. We collected data from patients with positive blood cultures for Enterococcus species isolates. The clinical data of patients who received ampicillin-containing regimens or glycopeptides as definitive therapy for ampicillin-susceptible E. faecalis/faecium bacteremia were reviewed. Multivariate logistic regression analysis was performed to identify risk factors for 28-day mortality.ResultsAmpicillin-susceptible E. faecalis/faecium accounted for 41.2% (557/1,353) of enterococcal bacteremia cases during the study period. A total of 127 patients who received ampicillin-containing regimens (N = 56) or glycopeptides (N = 71) as definitive therapy were included in the analysis. The 28-day mortality rate was higher in patients treated with glycopeptides (19.7%) than in those treated with ampicillin-containing regimens (3.6%) (p = 0.006). However, in the multivariate model, antibiotic choice was not an independent predictor of 28-day mortality (adjusted OR, 3.7; 95% CI, 0.6–23.6).ConclusionsGlycopeptide use was not associated with improved mortality in patients with ampicillin-susceptible E. faecalis/faecium bacteremia. This study provides insights to reduce the inappropriate use of glycopeptides in ampicillin-susceptible E. faecalis/faecium bacteremia treatment and promote antimicrobial stewardship.

Impact of sub-inhibitory antibiotic concentrations on biofilm formation among nosocomial isolates of Enterococcus species

Impact of sub-inhibitory antibiotic concentrations on biofilm formation among nosocomial isolates of Enterococcus species

Phenotypic and Genotypic Virulence Factors and Their Association with Antibiotic Resistance in Clinical Isolates of Enterococcus Species in Bangladesh

Phenotypic and Genotypic Virulence Factors and Their Association with Antibiotic Resistance in Clinical Isolates of Enterococcus Species in Bangladesh

VANCOMYCIN RESISTANT ENETROCOCCI- A STUDY ON PREVALENCEOF VANCOMYCIN RESISTANCE ENTEROCCI IN A TERTIARY CARE HOSPITAL IN SOUTH KERALA

Introduction: Vancomycin-resistant enterococci (VRE), are bacterial strains of the genus Enterococcus that are resistant to the antibiotic vancomycin. They have been associated with outbreaks of hospital-acquired (nosocomial) infections around the world. VRE can remain viable in the environment for an extended time period posing a problem for infection control in hospitals and nursing homes. They also pose a major therapeutic challenge as they possess intrinsic resistance to most of the commonly used antibiotics and can acquire resistance to most of the current available antibiotics. Assessment of the prevalence and changing trends of VRE infections is required to help plan infection control measures, which should be implemented in the hospital and also in the community to reduce the mortality and morbidity caused by these VRE infections. Objectives: This study was undertaken to determine the prevalence of Vancomycin resistance among Enterococcus species isolates obtained from clinical samples in a tertiary care hospital in southern India and also to detect resistant genes by molecular methods. A descriptive cross- Methods: sectional study was done on 150 non-duplicate isolates of Enterococcus species from different samples received at the Microbiology laboratory of Sree Gokulam Medical College and Research Foundation included consecutively from January 2021 to December 2021. Identication was based on Gram staining, colony morphologies, and biochemical tests. Antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method on Mueller Hinton agar. Vancomycin resistance was determined by Vancomycin screen agar and vancomycin E -test method. Statistical Package for Social Sciences (SPSS) was used for preparing and analysis of data. Out of the Results: 150 Enterococcus species, 2% (3) isolates were resistant to Vancomycin by Vancomycin screen agar & Vancomycin MIC test in which 2 were E. faecium and 1was E. faecalis. Out of 3 VRE, all were sensitive to Teicoplanin, so they were likely of vanB phenotype. Vancomycin resistant Enteroc Conclusion: occus species have emerged as important nosocomial pathogens in our institution with resistance of 2% per cent in our study. Increasing trend in the VRE rates, as seen in India and worldwide, need to be monitored and checked with active surveillance.

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.

Prevalence and antimicrobial resistance patterns of Enterococcus species isolated from laying hens in Lusaka and Copperbelt provinces of Zambia: a call for AMR surveillance in the poultry sector.

The use of antimicrobials in layer poultry production for improved production, growth promotion, prophylaxis and treatment purposes has contributed to the development of antimicrobial resistance (AMR) in poultry. In Zambia, there is a paucity of information on the prevalence and AMR patterns of Enterococcus species isolated from laying hens. This study investigated the prevalence and AMR patterns of enterococci isolated in layer hens in Lusaka and Copperbelt provinces of Zambia. A cross-sectional study was conducted from September 2020 to April 2021. Three hundred and sixty-five pooled cloacal swab samples were collected from 77 layer poultry farms. Enterococci identification and confirmation were performed using Analytical Profile Index (API 20 STREP) and 16S rRNA sequencing, respectively. A panel of nine antibiotics was used for antibiotic susceptibility testing and interpreted according to the CLSI 2020 guidelines. Data were analysed using SPSS version 23 and WHONET 2020. A total of 308 (83%) single Enterococcus species isolates were obtained and showed resistance to tetracycline (80.5%), erythromycin (53.6%), quinupristin/dalfopristin (53.2%), ampicillin (36.72%), vancomycin (32.8%), linezolid (30.2%), ciprofloxacin (11.0%), nitrofurantoin (6.5%) and chloramphenicol (3.9%). The prevalence of enterococci resistant to at least one antibiotic was 99.4% (n = 306), of which 86% (n = 265) were MDR. This study found a high prevalence of antimicrobial-resistant enterococci. The presence of MDR requires urgent intervention and implementation of AMR surveillance strategies and antimicrobial stewardship programmes in layer poultry production in Zambia.

Antibiogram Pattern and Virulence Trait Characterization of Enterococcus Species Clinical Isolates in Eastern India: A Recent Analysis.

Objective We aimed to evaluate the current antimicrobial susceptibility pattern and characterize putative virulence traits among Enterococcus species isolates from various clinical specimens in view of their increased isolation rates in both community-related and serious nosocomial infections, as well as resistance to many antibiotics. Methods Study (April 2017–March 2018) included consecutive, nonrepeated, discrete, and clinically significant isolates of enterococci. Susceptibility testing included detection of high-level aminoglycoside-resistant (HLAR) and glycopeptide-resistant enterococci (GRE). All screen-positive GRE isolates were investigated by polymerase chain reaction for species confirmation and presence of vanA/vanB genes. Virulence genes ace , asa1 , cyt , efa , esp , gelE , and hyl were investigated by molecular methods. Hemolysin and biofilm production were studied using phenotypic methods. Results Of 111 isolates, 89 (80.1%), 16 (14.4%), and 6 (5.4%) were from urine, pus, and blood, respectively, consisting predominantly of E. faecalis (67, 60.4%) and E. faecium (32, 28.8%). E. hirae (5, 4.5%) was the predominant non- E. faecalis non- E. faecium isolate. Other species were E. durans (4, 3.6%), E. avium (2, 1.8%), and E. mundtii (1, 0.9%). Seven (6.3%) out of the 111 isolates were GRE, all vanA genotype. HLAR was observed in 70 (63.1%) isolates, significantly higher in E. faecium than E. faecalis (81.2 vs. 58.2%; p < 0.05). All were susceptible to daptomycin. Hemolysin activity and biofilm production were observed in 38 (34.2%) and 36 (32.4%) isolates. Most frequent virulence genes were efa (77, 69.4%), ace (71, 63.9%), asa1 (67, 60.3%), and gelE (66, 59.4%). There was a predominant association of esp and hyl genes with E. faecium and that of the other genes with E. faecalis . Conclusion The study will contribute to the existing limited data on virulence trait characterization of clinical E. spp. isolates in India. At the same time, it will help to serve as a guide in the choice of empirical therapy in enterococcal infections leading to favorable clinical outcomes by decreasing the clinical failure, microbiological persistence, and associated mortality, and will lead to future studies on controlling the spread of virulent and multiresistant isolates.

Bacteriological profile and antibiotics sensitivity patterns among neonates admitted at Birat Medical College Teaching Hospital

Background: Neonatal sepsis still remains serious and potentially life-threatening events with a mortality rate of up to 50%. The current practice of starting empirical antibiotic therapy in all neonates showing infection-like symptoms results in their exposure to adverse drug effects, nosocomial complications, and in the emergence of resistant strains. The antibiotic sensitivity pattern of organisms is changing very rapidly over a short period which is varying from country to country, one place to another, and one institute to another. Therefore, periodic evaluation of sensitivity patterns is essential for rational and appropriate use of antibiotics. Aims and Objectives: This study aims to see bacteriological profile and their antibiotics sensitivity among the sepsis suspected neonates at the neonatal intensive care unit of Birat Medical College Teaching Hospital (BMCTH). Materials and Methods: It was a cross-sectional descriptive study from July 21, 2021, to December 21, 2021. Sample size of 138 was included in the study. Neonates were selected by non-probability consecutive sampling techniques. Neonatal sepsis suspected neonates and plan to treat with injectable antibiotics by the treating pediatrician were included in the study. All patients included were started on empirical antibiotics after drawing samples for blood cultures and CRP along with other investigations. Bacteriological profile and their sensitivity to different antibiotics were collected from blood culture reports. Data collection was done using a specifically designed questionnaire. The descriptive and inferential statistics were used for data analysis. The test of significance was done by the Chi-square test. P&lt;0.05 was considered statistically significant. Results: Among the 46 blood culture-proven sepsis, the most common organism isolated was Staphylococcus aureus which was 33 (71.7%). Among the isolated S. aureus, 100% were sensitive to colistin sulfate and injectable linezolid, 93.1% sensitive to injectable meropenem, 85.7% sensitive to injectable piperacillin and tazobactam combination, 83.3% sensitive to injectable vancomycin, and 85.7% sensitive to injectable amikacin but only 40.7% to injectable cefotaxime. Isolated Acinetobacter species were found 100% sensitive to colistin sulfate and meropenem, and 80% sensitive to cefotaxime and amikacin but only 66.7% sensitive to injectable piperacillin and tazobactam combination. Only one neonate had Klebsiella isolated in blood culture which was 100% resistant to injectable cefotaxime but was sensitive 100% to Meropenem, piperacillin-tazobactam, and amikacin. Isolated Enterococcus species were 100% sensitive to piperacillin-tazobactam combination, meropenem, and imipenem but only 66.7% sensitive to injectable cefotaxime. Conclusion: Gram-positive isolates were the predominant pathogens among enrolled neonatal sepsis suspected neonates at Birat medical college teaching hospital (BMCTH). Based on our findings, a combination of cefotaxime and amikacin can be used as first-line therapy. However, cefotaxime only had moderate sensitivity, so change to piperacillin-tazobactam and vancomycin or linezolid as second-line therapy can be considered early in case of no improvement or deterioration, or combination of vancomycin and meropenem as third line would be the appropriate empirical therapy at BMCTH. However, the use of the broad-spectrum antibiotics as empirical therapy should be evaluated in the long run and should be used cautiously and modified to narrow spectrum antibiotics, as guided by the culture and susceptibility report at the earliest possible.

In-vitro Activity of Tigecycline versus Daptomycin against Clinical Isolates of Enterococcus Species

Introduction: Tigecycline is a potential therapeutic agent for multidrug resistant gram positive and gram negative organisms. The clinical efficacy of synergic combination of daptomycin with betalactam antibiotics have been described against various species of Enterococcus isolates. Aim: To detect the in-vitro activity of tigecycline and daptomycin against Enterococcus species and their antimicrobial activity with Vitek 2 automated system. Materials and Methods: This was a cross-sectional study conducted at Department of Microbiology, Vinayaka Mission’s Kirupananda Variyar (VMKV) Medical College and Hospitals, Salem, Tamil Nadu, India. Isolates of Enterococcus obtained over a period of two years from March 2016 - March 2018 from various clinical samples were identified by standard biochemical method and their antimicrobial susceptibility pattern was determined. Minimum Inhibitory Concentration (MIC) of tigecycline and daptomycin was determined by Vitek 2 automated system. Analysis of data was done by using frequency distribution and percentage. Results: Out of 211 Enterococcus isolates studied, 23 (10.90%) isolates showed decreased susceptibility to daptomycin with MIC of ≥8 µg/mL. All isolates showed 100% susceptibility to tigecycline. Conclusion: The present study showed potent antimicrobial activity of tigecycline against various species of Enterococcus. Decreased susceptibility to daptomycin has been observed among the study isolates. Further clinical investigations are required to know the potential benefits of these agents in therapy.

Occurrence of New Delhi Metallo-Beta-Lactamase 1 Producing Enterococcus Species in Oghara Water Nexus: An Emerging Environmental Implications of Resistance Dynamics.

Various members of the enteric bacteria in recent times are evolving diverse survival mechanisms for antibiotic therapy resulting in failure of treatment in infection and disease cases. The Enterococcus species are potential strains implicated in gastrointestinal tract infection and are recently evolving in the resistance mechanism. The study evaluates the occurrence of New Delhi Metallo-beta-lactamase 1 (NDM-1) amongst Enterococcus species using the phenotypic and genomic characterization of environmental strains in the Oghara water nexus. Presumptive isolates of Enterococcus species were retrieved from various sampled water sources and confirmed using polymerase chain reaction (PCR). Antibiotic susceptibility testing was conducted on confirmed isolates using Kirby-Bauer disk diffusion methods. The result reveals 63 genus isolates confirmed Enterococcus species, of which 42 (67%) were Enterococcus faecium, 15 (23%) were Enterococcus faecalis, and 6 (10%) were other Enterococcus species. Fourteen among the E. faecalis isolates show resistance to Ertapenem-EDTA, while 17 (44.8%) of the E. faecium show resistance to Ertapenem-EDTA to presumptively reveal their NDM-1 phenotype. The PCR detection of the NDM-1 gene further confirmed 23 (36.5%) isolates as positive genotypes amongst the isolates that previously showed presumptive NDM-1 phenotype. It was also observed that 10 (15.9%) of Enterococcus faecium members harbored the NDM-1 genotype, whereas 8 (12.7%) members of the Enterococcus faecalis harbored the NDM-1 genotype. The observation of such resistance determinants necessitates a call for the adroit application of relevant therapeutics in the management of related infections and an environmental health caution to prevent the spread of such resistance potential enteric bacteria pathogens.

Detection and Antibiogram Profile of Enterococcus Species from Local Cheese Sample within Ikare and Akungba Akoko, Ondo State Nigeria

Enterococci are part of the normal intestinal flora of humans and animals and are increasingly recognized as significant human pathogens and capable of causing major therapeutic challenges. The aim of this study was to isolate, identify and determine the antimicrobial susceptibility pattern of Enterococcus species in two local cheese sample collected from Akungba and Ikare. The isolation of Enterococcus was carried out using standard culture-based techniques. Antimicrobial susceptibility profile of the Enterococcus species was determined using disk diffusion method. A total number of 93 presumptive Enterococcus species were recovered from forty two different samples over a period of three months. The bacterial count observed on the Bile Aesculin agar ranged from 1.5x104 cfu/ml to 4.6x104 cfu/ml with Akungba sample having the highest bacterial load of 4.6x104 cfu/ml. The Morphology and biochemical characteristics of suspected Enterococcus spp. isolated from the cheese sample revealed Enterococci feacalis as the isolated bacteria. The isolated Enterococcus species were tested against a panel of six antibiotics which include Penicillin G, Vancomycin, Tetracycline, Nitrofurantoin, Ciprofloxacin and Imipenem. It was observed that the isolates were susceptible to tetracycline, imipinem and ciprofloxacin while they are resistant to ciprofloxacin and vancomycin. The prevalence of Enterococci was confirmed with Enterococcus feacium and Enterococcus faecalis as the predominant species isolated in both cheese sample. The ability of Enterococcus species to survive a range of adverse environments allows multiple routes of cross-contamination of Enterococci in causing human disease, including those from food. Overall, greater understanding of the ability of Enterococcus species to survive stresses, of virulence traits and especially of increasing antibiotic resistance, is needed in order to fully appreciate the complexity of Enterococcus species in causing disease.

Phenotypic Study on the Bacterial Isolates from Equine with Respiratory Disorders regarding Antimicrobial Drug Resistance

Upper respiratory tract infection and pneumonia in foals are primarily caused by a bacterial infection. Gram-negative bacteria are commonly found in neonatal pneumonia although gram-positive and mixed infections could be accompanied. The current study aimed to detect the different pathogens causing respiratory disorders in the equine, describe the antimicrobial resistance in these pathogens, and determine the types of antimicrobial isolates. A total of 203 different samples were collected from 42 horse foals, 5 adult horses, and 4 donkey foals from June 2019 to April 2020. All samples were subjected to bacteriology analysis and isolated bacteria were analyzed using susceptibility test for different antibacterial agents. The findings indicated that 38 (74.5%) animals were positive for the isolation of bacteria causing respiratory disorders. The most predominant isolates were Klebsiella pneumoniae subsp. Pneumoniae followed by Staphylococcus aureus, Streptococcus equi, Pseudomonas aeruginosa, Streptococcus zooepidemicus, Proteus mirabilis, Rhodococcus equi, Stenotrophomonas maltophilia, and Streptococcus mitis. Stenotrophomonas maltophilia is isolated from all organs, including the lungs. All K. pneumoniae isolates were sensitive to lomefloxacin, cefotaxime, meropenem, enrofloxacin, neomycin, and chloramphenicol. The Pseudomonas aerugenosa (P. aeruginosa) is sensitive to aztreonam and 20% of isolates sensitive to Piperacillin-tazobactam. All Proteus mirabilis were sensitive to ampicillin-sulbactam, piperacillin-tazobactam, and cefoperazone. Stenotrophomonas maltophilia was only sensitive to oxytetracycline and lomefloxacin. Staphylococcus aureus was susceptible to Piperacillin-tazobactam (50%), 25% to lomefloxacin; Streptococcus equi were sensitive to vancomycin 33.3% while 16.7% to erythromycin and doxycycline, Streptococcus zooepidemicus (100%) were sensitive to cefotaxime, meropenem, and doxycycline. All isolates of Enterococcus species were sensitive to penicillin, piperacillin-tazobactam, and lomefloxacin. Moreover, Rhodococcus equi (one isolate) was only sensitive to clarithromycin. The antimicrobial susceptibility test illustrated the presence of multidrug-resistant and pan-drug resistant isolates which proved the indiscriminate and extensive use of antibiotics. In conclusion, resistance monitoring data and risk assessment identified several direct and/or indirect predisposing factors to be potentially associated with MDR development in the equine health sector of Egypt. The predisposing factors may be attributed to insufficient veterinary healthcare, monitoring, and regulatory services, in addition to the intervention of animal health service providers, and/ or farmers’ lack of knowledge about drugs. The misuse and overuse of antibiotics have led to the evolution of antibiotic-resistant bacteria in equine in Egypt.

Pattern in Minimum Inhibitory Concentration of Vancomycin and Tigecycline on Clinical Isolates of Enterococcus Species Isolated from Clinical Samples at our Tertiary Care Hospital

Background: Genus Enterococcus have emerged as nosocomial pathogens. Urinary tract infections followed by intra-abdominal abscesses, Wounds, usually intra-abdominal or pelvic, are the next most common sites. Bacteremia is the third most common infection caused by Enterococci. Enterococcal meningitis is rare and is seen primarily in neonates and inpatients who have undergone complicated neurosurgical procedures [4]. There is an increasing role of Enterococci in nosocomial infections in the recent years mostly because of their intrinsic resistance to many clinically useful antibacterial drugs. One of the leading cause of nosocomial infection is Vancomycin-resistant Enterococci (VRE). For good therapy an effective, accurate and early detection of VRE along with Minimum Inhibitory Concentrations (MIC) is necessary. Tigecycline has a broad spectrum of activity against enterococci (vancomycin-susceptible). Haemolysin is a cytolytic protein and the producing strains of Enterococci have been shown to be associated within creased severity of infection [9]. In order to know the current scenario of minimum inhibitory concentration of Vancomycin and Tigecycline and the production of Haemolysin by some strains of Enterococci, the present study has been done. Methods: This study was performed on Clinical isolates of Enterococcus which were received from tertiary care hospitals and processed at Department of Microbiology, Kasturba Medical College, Mangalore and Microbiology diagnostic laboratory (KMC hospital, Ambedkar circle), Mangalore. The study was done for a period of 6 months from Nov 2017-May2018. Convenient non-random sampling method was followed to collect clinical isolates. All isolates of Enterococcus from various clinical specimens like pus, deep tissue, urine, blood and body fluids were included in the study. Result: Out of 100 Enterococcus isolates collected, majority were of E. faecium. Among all the isolates, 5% were resistant to vancomycin, but 100% sensitivity to tigecycline. Hemolysin produced by 46% of the total isolates. It has shown its association of the Enterococcus species to various antibiotics and their resistant pattern.

Isolation of Enterococcus Species from Food Sources and Its Antibacterial Activity against Staphylococcus Aureus

The microbial production of substances that have the ability to inhibit the growth of other microorganisms is possibly the most common defense strategy developed in nature. Microorganisms produce a variable collection of microbial defense systems, which include antibiotics, metabolic by-products, lytic agents, bacteriocins and others. The aim of the present study was to isolate and identify Enterococcus spp. and its most prevalent species from food samples and determine its antibacterial activity against Staphylococcus aureus isolates. A total of 50 food samples from different sources (dairy products (20 samples) and vegetables and fish (15 samples each)) were collected from different local markets in Baghdad and cultured. Enterococcus spp were isolated from only 32 food samples. E. faecium was the most predominant species which was recovered from 20 samples (62.5 %), 10 dairies, 7 vegetables, and 2 fish. E. faecalis was found in 8 samples (25 %), 5 vegetables and 3 fish. E. avium was recovered 6.25% as well as E. gallinarium (2 samples for each) Enterococcus avium were all isolated from dairy products but Enterococcus gallinarium one sample isolated from dairies and the other from fish. This study indicates the presence of Enterococcus spp. in the food samples and the ability of these bacteria to produce antibacterial substances which are active against closely related clinical isolates.

High-level resistance to aminoglycosides and ampicillin among clinical isolates of Enterococcus species in an Iranian referral hospital.

Background and Objectives:Nowadays, high-level aminoglycosides and ampicillin resistant Enterococcus species are among the most common causes of nosocomial infections. The present study was conducted to determine the prevalence of high-level resistance to aminoglycosides and ampicillin among clinical isolates of Enterococcus species in Ardabil, Iran.Materials and Methods:In this cross–sectional study, a total of 111 Enterococcus species were collected from different clinical specimens between 2013 and 2015. Enterococcus species were identified using standard phenotypic and genotypic methods. BHI agar screen and agar dilution methods were used for detection of high-level gentamicin and streptomycin resistance (HLGR and HLSR) and minimal inhibitory concentration (MIC) of ampicillin, respectively.Results:Of 111 clinical isolates, 59 (53.2%) and 25 (22.5%) isolates were E. faecalis and E. faecium, respectively, based on the PCR results. Totally, 60.3% and 56.7% of isolates were HLGR and HLSR, respectively, as well as 51.35% were HLGR plus HLSR. Among HLGR isolates, 36 (61.01%), 18 (72%) and 13 (48.14%) were E. faecium, E. faecalis and non-faecalis non-faecium species, respectively. Among HLSR isolates, 33 (55.93%), 16 (64%) and 14 (51.85%) were E. faecalis, E. faecium and non-faecalis non-faecium species, respectively. All HLGR isolates contained aac(6′)Ie-aph(2″)Ia gene. Overall, the prevalence of high-level ampicillin resistance among Enterococcus species was 17.1%. For E. faecalis, E. faecium and non-faecalis non-faecium species, ampicillin resistance rates were as follows: 11 (40.74%), 7 (28%) and 1 (1.69%), respectively. For aminoglycoside antibiotics, the resistance rate was significantly higher in E. faecium isolates and for ampicillin it was higher in E. faecalis isolates.Conclusion:The frequency of high-level aminoglycoside resistant enterococcal isolates in our hospital was high and significant ampicillin resistance was noticed. This would require routine testing of enterococcal isolates for HLAR and ampicillin susceptibility.

Detection of high level aminoglycoside resistance genes among clinical isolates of Enterococcus species

BackgroundEnterococci are intrinsically resistant to clinically achievable concentrations of aminoglycosides. However, high-level resistance to aminoglycosides (HLAR) is primarily due to the acquisition of genes encoding aminoglycoside-modifying enzymes (AMEs). Aminoglycosides along with cell wall inhibitors are given clinically for treating enterococcal infections. The current study was conducted to investigate the rate of HLAR and to determine aminoglycoside resistance encoding genes profile in enterococcal isolates from different clinical specimens.ResultsFrom 120 Enterococcus species, 50 (41.7%) enterococcal isolates were proven to have HLAR, 78% (39/50) have high-level gentamicin resistance (HLGR), and 74% (37/50) were high-level streptomycin-resistant (HLSR). HLGR isolates carried aminoglycoside modifying gene aac (6′)-Ie-aph (2′)-Ia in 26/39 (66.7%) of isolates, whereas 32/37 (86.5%) of HLSR carried aph (3′)-IIIa gene and were observed in E. faecalis, E. faecium, E. gallinarum, and E. casseliflavus. The aph (2′)-Ib, aph (2′)-Ic, and aph (2′)-Id that encode HLGR could not be detected.ConclusionsThe high detection rate of HLAR among the studied Enterococcus species and the coexistence of HLGR and HLSR strains provide crucial insights to the necessity of routine testing for HLAR in the microbiology lab. The main AME genes among HLGR and HLSR enterococci were aac (6′)-Ie-aph (2″)-Ia and aph (3′)-IIIa, respectively.

Identification and Virulence Factors of Enterococcus Species Isolated from Raw Milk

Four enterococci isolated from raw milk samples grown on Enterococcus selective medium were identified on genus level by several conventional methods, and species levels using API 20 Strep. The incidence of virulence factors (antibiotics susceptibility, vancomycin resistance, haemolytic activity, production of gelatinase, aggregation substances, hydrophobicity and biofilm formation) were also examined for the isolated Enterococcus species. Results showed that the tested cultures grown on Enterococcus selective medium BEA showed similar behavior that all were able to grow at 10°C and 45°C, pH 9.6, NaCl 6.5%, tolerate growth in the presence of 40% bile and 0.04% sodium azide. They also survived 60°C/30 min. Four tested Enterococcus spp. Were found belonging to E. faecium, E. durans and E. faecalis, being one strain, two strains and one strain, respectively. E.faecium Rm1, E.durans Rm2 and E.durans Rm3 strains were found to be safe as they did not harbored any of tested virulence trait or multi antibiotic resistant. Results also showed that E.faecalis Rm4 was not safe as it harbored some of virulence factors and resisted multi antibiotics. Finally, E.faecium Rm1, E.durans Rm2 and E.durans Rm3 could be considered ideal strains, which could be used as adjunct or starter cultures as they were free from virulence determinants and sensitive to all antibiotic examined.

Antibiotic Susceptibility Testing, Plasmid Detection and Curing of Clinically Isolated Enterococcus Species

Vancomycin resistant enterococci (VRE) are a major medical concern globally. Their significantly greater prevalence and the ability to transfer resistance to vancomycin from other bacteria made them an object of interest and intense research. The isolates of Enterococcus sp. were subjected to antibiotic susceptibility testing before curing. The three Enterococcus species exhibited different antibiotic resistance profile. Pre-curing antibiotic resistance of nosocomial isolates compared with community acquired isolates revealed that high percentage of the nosocomial isolates were resistant to antibiotics compared to community isolate. Post-curing antibiograms of the isolates showed different resistant and susceptibility pattern. Also, DNA plasmid pre-curing and post curing analysis of the isolates showed different resistance pattern. Six of the 15 representative isolates selected on the basis of their high pre-curing antibiotic resistance for plasmid analysis with 0.8% agarose electrophoresis were positive for plasmid DNA. Four (4) of the positive isolates (E. faecium, E. faecium, E. faecalis, and E. avium) had plasmid fragment of greater than 1000 bp while two (2) of them (E. faecalis and E. faecalis) had fragments of between 100 and 500 bp. The remaining nine (9) had no plasmid DNA. The study revealed the pathogenicity factors demonstrated with the enterococcal isolates.

Human Health Risks Associated with Antimicrobial-Resistant Enterococci Isolated from Poultry and Human

Enterococcus is a commensal organism found in poultry and the human gastrointestinal tract. Enterococcus has emerged as a major zoonotic and nosocomial pathogen. This study aimed to determine the occurrence of Enterococcus species infections among poultry and human, to determine the antibiotic resistance pattern, virulence profile and phylogenetic background of some Enterococcus spp. isolates from poultry and humans. A total of 480 samples (70 from chickens, 30 from pigeon and 20 from ducks) were collected from (liver, heart, intestine and cloacal swabs). In addition, a total number of 120 samples (urine, pleural fluid, stool, wound and pus) from human were collected. The susceptibility profile of the isolates to nine antibiotics were determined using disk diffusion method. Molecular detection for virulence factors was done for all isolates. Partial sequences of 16rRNA gene was applied to isolates from human and poultry. Results revealed that the prevalence of Enterococcus isolation from poultry flocks was (53.3%) from poultry and from human (61.7%). The most predominant isolated Enterococcus species were E. faecium and E. faecalis. The antibiogram showed sensibility of Enterococcus spp. to vancomycin with multi-drug resistance to many antibiotics. Higher detection rates of Vancomycin genes type A, B, and C were detected among human and poultry isolates. The virulence genes esp (enterococcal surface protein) and cylA (hemolysin) genes were frequent among avian and human isolates. In conclusion, there were many similarities in Enterococcus species distribution, virulence gene profile and antibiotic resistance pattern and identity in 16SrRNA gene partial sequences of isolated Enterococci from poultry and human that supporting the zoonotic risk of Enterococcus.

Major ecological shifts within the dominant nonstarter lactic acid bacteria in mature Greek Graviera cheese as affected by the starter culture type

Traditional Greek Graviera cheese is often produced from thermized milk to control undesirable bacterial contaminants. Since thermization also reduces the desirable lactic acid bacteria (LAB) microbiota of raw milk, natural undefined or commercially defined starters are used. This study evaluated effects of the type of starter added to bulk thermized milk on the microbiology of mature (day-90) Graviera cheese. Cheeses produced with a natural starter culture (NSC) in non-concentrated yogurt-like form or a commercial starter culture (CSC) containing Streptococcus thermophilus and various Lactococcus lactis strains in concentrated freeze-dried form, were analyzed microbiologically, and 200 LAB isolates (100 from each type of cheese) were identified. The LAB microbiota of the mature CSC-cheeses was dominated by nonstarter strains of Lactobacillus paracasei and Lb. plantarum whereas indigenous Enterococcus faecium and E. durans strains of high phenotypic and genotypic diversity predominated in the respective NSC-cheeses. Populations of enterococci in CSC-cheeses were subdominant by 10 to 100-fold compared with those in NSC-cheeses; E. faecium was the most frequently isolated Enterococcus species from the mature CSC-cheeses. Sporadic or no isolates of other LAB species, including the commercial S. thermophilus and Lc. lactis starter strains in the CSC-cheeses and the natural S. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus starter strains plus indigenous Lactococcus, Leuconostoc and E. faecalis in the NSC-cheeses, were detected. In conclusion, the replacement of the NSC with the CSC controlled growth of dairy enterococci in favor of mesophilic nonstarter lactobacilli during ripening. While safety concerns associated with the inefficiency of NSCs to prevent outgrowth of indigenous enterococci suggest that CSCs should be preferred by traditional Greek Graviera cheese processors, panel sensory evaluations showed that the NSC-ripened cheeses were of slightly lower appearance but of occasionally higher flavor scores than the CSC-ripened cheeses.