Analysis of the phenotypic and genotypic antimicrobial resistance profiles of clinically significant enterococci isolated in the Provincial Specialist Hospital in Lublin, Poland

Abstract The increasing significance of enterococci as healthcare-associated pathogens can be linked to their limited susceptibility to antibiotics. In this study, phenotypic and genotypic resistance profiles of 35 [n=18 E. faecium (Efm); n=17 E. faecalis (Efs)] invasive isolates cultured from hospitalized patients were analysed. Phenotypic identification was verified by the multiplex PCR targeting the 16S rDNA and the ddl genes encoding for the Efs and Efm – specific ligases. Antimicrobial susceptibility was determined using the disc diffusion method and E-tests. The high-level streptomycin resistance (HLSR), high-level gentamicin resistance (HLGR) and glycopeptide resistance was verified by amplification of the ant(6)-Ia, aac(6’)-Ie-aph(2’’)-Ia, as well as vanA and vanB genes, respectively. More than 70% of all isolates were cultured from patients in the Intensive Care and Internal Medicine Units. Blood was the predominant (77%) site of isolation. All Efm isolates were resistant to ampicillin, imipenem, and norfloxacin; 17 isolates demonstrated high-level aminoglycoside resistance (HLAR), including 27.7% with HLSR, 38.8% with HLGR and 27.7% with both phenotypes. HLAR was also common in Efs (HLSR>70%, HLGR>50%), followed by norfloxacin (64.7%) and ampicillin (11.7%) resistance. The ant(6)-Ia and aac(6’)-Ie-aph(2’’)-Ia genes were detected in >90% of the HLSR and HLGR isolates, respectively. Glycopeptide resistance was detected in 4 (22.2%) Efm isolates and mediated by the vanA gene. 19 (54.3%) isolates were multidrug resistant, including 17 (89.5%) Efm. All isolates were susceptible to linezolid. The study constitutes a contribution to the analysis of enterococcal antimicrobial resistance in Polish hospitals. The monitoring of enterococcal prevalence and antimicrobial resistance is crucial to control and prevent infections.

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Frequency of vancomycin-resistant Enterococci isolated from blood cultures from 2008 to 2010

Medicinski pregled ◽

10.2298/mpns1110481m ◽

2011 ◽

Vol 64 (9-10) ◽

pp. 481-485 ◽

Cited By ~ 3

Author(s):

Mira Mihajlovic-Ukropina ◽

Deana Medic ◽

Zora Jelesic ◽

Vera Gusman ◽

Biljana Milosavljevic

Keyword(s):

Antimicrobial Agents ◽

Multidrug Resistant ◽

Blood Cultures ◽

Hospitalized Patients ◽

Diffusion Method ◽

Aminoglycoside Resistance ◽

Vancomycin Resistant Enterococci ◽

Enterococcus Spp ◽

Vancomycin Resistant ◽

High Level

Introduction. Enterococci are important hospital-acquired pathogens. The most commonly isolated species of the genus, Enterococcus faecalis and Enterococcus faecium are the third to fourth-most prevalent nosocomial pathogens worldwide. The aim of this study was to determine the frequency of resistance to vancomycin and other antimicrobial agents of Enterococcus spp strains isolated from blood cultures of hospitalized patients. Material and methods. During the three-year period, from 2008 to 2010, 132 strains of Enterococcus spp isolated from blood cultures of hospitalized patients were tested for their susceptibility to ampicillin, vancomycin, gentamycin (high-level resistance), erythromycin, chloramphenicol, teicoplanin, ciprofloxacin by disc diffusion method according to the Clinical and Laboratory Standards Institute recommendations. Susceptibility of vancomycin resistant E. faecium to the same antibiotics and to linezolid, quinopristin/dalfopristin and tigecyclin was determined using VITEK system. Results and discussion. Resistance to vancomycin was detected in 21 (15.9%) Enterococcus spp strains. The percentage of resistance to other antimicrobial agents varied from 23.1% for chloramphenicol to 81.3% for ciproflxacin. All vancomycin resistant enterococci were identified as E. faecium and belonged to phenotype VanA. The resistance to other antibiotics was very high, except for linezolid and quinopristin/dalfopristin (4.7%). The high-level aminoglycoside resistance was 87.6% for gentamycin and 95.2% for streptomycin. All isolates were resistant to ampicillin, teicoplanin and ciprofloxacin. Conclusion. The detected high frequency of multidrug-resistant isolates among vancomycin resistant enterococci is of great importance and suggests the need for further monitoring of susceptibility in order to take adequate measures to prevent and control spreading of resistant strains.

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Resistance pattern of enterococcus for high level aminoglycosides and vancomycin in blood culture of admitted patients

International Journal of Bioassays ◽

10.21746/ijbio.2016.01.0010 ◽

2016 ◽

Vol 5 (01) ◽

pp. 4756

Author(s):

Shadma Yaqoob

Keyword(s):

Blood Culture ◽

Multidrug Resistant ◽

Screening Tests ◽

Diffusion Method ◽

Resistance Pattern ◽

Aminoglycoside Resistance ◽

Vancomycin Resistant ◽

Blood Specimens ◽

High Level ◽

Clinical Conditions

Enterococci have emerged as important nosocomial pathogens from a variety of clinical conditions and the major reason for this is the trend of increasing antimicrobial resistance and enterococcal bacteraemia results in a high mortality. The present study was undertaken to determine the occurrence, species prevalence, antibacterial resistance, with a special reference to vancomycin and high level aminoglycoside resistance. Material and methods: The study was conducted on blood culture isolates. The antibiotic susceptibility of isolates by the Kirby Bauer disc diffusion method was done according to the CLSI guidelines. Screening tests for high level aminoglycosides and vancomycin and minimum inhibitory concentration (MIC) tests for vancomycin was done. The blood specimens were cultured and suspected growths were identified to species level and found to consist mostly of E. fecalis (70%). VRE accounted for 2 (91%) isolates and high level aminoglycoside resistance was seen in 47.82 and 60.86 isolates. The E. faecium isolates were more drug resistant than the E. faecalis isolates. Linezolid and Teicoplanin showed good anti-enterococcal activity. This study shows an emergence of Vancomycin resistant enterococcus (VRE) along with increased rate of multidrug-resistant enterococci. Regular surveillance of antimicrobial susceptibilities and treatment of enterococcal infections should be done effectively to limit the spread of multidrug resistance.

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

Microorganisms ◽

10.3390/microorganisms9050885 ◽

2021 ◽

Vol 9 (5) ◽

pp. 885

Author(s):

Dorcas Oladayo Fatoba ◽

Akebe Luther King Abia ◽

Daniel G. Amoako ◽

Sabiha Y. Essack

Keyword(s):

Antimicrobial Resistance ◽

Agricultural Soil ◽

Multidrug Resistant ◽

Diffusion Method ◽

Resistant Bacteria ◽

Manure Application ◽

Unamended Soil ◽

Enterococcus Spp ◽

Chicken Litter ◽

Amended Soil

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.

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Molecular Detection and Antibiotyping of Multidrug-Resistant Salmonella Isolated from Houseflies in a Fish Market

Pathogens ◽

10.3390/pathogens8040191 ◽

2019 ◽

Vol 8 (4) ◽

pp. 191 ◽

Cited By ~ 5

Author(s):

Sobur ◽

Hasan ◽

Haque ◽

Mridul ◽

Noreddin ◽

...

Keyword(s):

Molecular Detection ◽

Multidrug Resistant ◽

Diffusion Method ◽

Resistant Bacteria ◽

Salmonella Spp ◽

Disk Diffusion Method ◽

Antibiotic Resistant ◽

Fish Market ◽

Pcr Method ◽

High Level

Houseflies (Musca domestica) are well-known mechanical vectors for spreading multidrug-resistant bacteria. Fish sold in open markets are exposed to houseflies. The present study investigated the prevalence and antibiotypes of multidrug-resistant (MDR) Salmonella spp. in houseflies captured from a fish market. Direct interviews with fish vendors and consumers were also performed to draw their perceptions about the role of flies in spreading antibiotic-resistant bacteria. A total of 60 houseflies were captured from a local fish market in Bangladesh. The presence of Salmonella spp. was confirmed using PCR method. Antibiogram was determined by the disk diffusion method, followed by the detection of tetA, tetB, and qnrA resistance genes by PCR. From the interview, it was found that most of the consumers and vendors were not aware of antibiotic resistance, but reported that flies can carry pathogens. Salmonella spp. were identified from the surface of 34 (56.7%) houseflies, of which 31 (91.2%) were found to be MDR. This study revealed 25 antibiotypes among the isolated Salmonella spp. All tested isolates were found to be resistant to tetracycline. tetA and tetB were detected in 100% and 47.1% of the isolates, respectively. Among the 10 isolates phenotypically found resistant to ciprofloxacin, six (60%) were found to be positive for qnrA gene. As far as we know, this is the first study from Bangladesh to report and describe the molecular detection of multidrug-resistant Salmonella spp. in houseflies in a fish market facility. The occurrence of a high level of MDR Salmonella in houseflies in the fish market is of great public health concerns.

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Vancomycin and high-level aminoglycoside resistance in Enterococcus species

Microbiology Research ◽

10.4081/mr.2016.6441 ◽

2016 ◽

Vol 7 (1) ◽

Cited By ~ 1

Author(s):

Seyda Ozarslan Kurtgoz ◽

Burcin Ozer ◽

Melek Inci ◽

Nizami Duran ◽

Erkan Yula

Keyword(s):

Vancomycin Resistance ◽

Automated System ◽

Diffusion Method ◽

Beta Lactamase ◽

Aminoglycoside Resistance ◽

Disk Diffusion Method ◽

Gradient Diffusion ◽

Gentamicin Resistance ◽

Polymerase Chain ◽

High Level

The aim of the study was to investigate vancomycin and high-level aminoglycoside resistance (HLAR) in Enterococcus species by phenotypic and genotypic methods. A hundred Enterococcus strains were included in the study. Antimicrobial susceptibilities of strains were investigated by automated system, betalactamase production was investigated by nitrocefin disks, vancomycin resistance and HLAR were investigated by gradient diffusion method (GDM) and disk diffusion method, respectively. For detection of vancomycin and high-level gentamicin resistance (HLGR) genes, polymerase chain reaction was used. Teicoplanin linezolid, vancomycin, ampicillin, penicillin are the most susceptible antibiotics and strains were detected not to produce beta lactamase. Vancomycin resistance was detected in ten isolates by automated system and in only five isolates by GDM. Five isolates carrying VanA gene were determined. The ratio of HLGR and high-level streptomycin resistance was found 40 and 63% respectively. aac (6’)-1eaph (2’’)-1a gene was detected in 58% of strains. E. faecium strains were found more resistant to the antibiotics than the other species. Beta lactamase was detected in none of strains. The automated system detected vancomycin resistance in more strains than GDM. Therefore it is concluded that strains, which were detected to be resistant to vancomycin, should be confirmed by GDM. The ratio of VanA gene in strains is consistent with other studies. The HLAR ratio was found in about half of strains. The ratio of aac(6’)-1e-aph(2’’)-1a gene, which is the most reported gene in our country and other countries and one of the HLGR genes investigated in our study, was detected 58%.

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Antibiotic Resistance of Enterobacteriaceae Isolated from Fresh Fruits and Vegetables and Characterization of their AmpC β-Lactamases

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-089 ◽

2019 ◽

Vol 82 (11) ◽

pp. 1857-1863 ◽

Cited By ~ 2

Author(s):

ZAHRA S. AL-KHAROUSI ◽

NEJIB GUIZANI ◽

ABDULLAH M. AL-SADI ◽

ISMAIL M. AL-BULUSHI

Keyword(s):

Antibiotic Resistance ◽

Fruits And Vegetables ◽

Multidrug Resistant ◽

Diffusion Method ◽

Resistant Bacteria ◽

Disk Diffusion Method ◽

Antibiotic Resistant ◽

Amoxicillin Clavulanic Acid ◽

Clinically Significant ◽

Enterobacter Asburiae

ABSTRACT Enterobacteria may gain antibiotic resistance and be potent pathogens wherever they are present, including in fresh fruits and vegetables. This study tested the antibiotic resistance of enterobacteria isolated from 13 types of local and imported fresh fruits and vegetables (n = 105), using the standard Kirby-Bauer disk diffusion method. Phenotypic and genotypic characterizations of AmpC β-lactamases were determined in cefoxitin-resistant isolates. Ten percent of the enterobacteria tested (n = 88) were pansusceptible, 74% were resistant to at least one antibiotic, and 16% were multidrug resistant. Enterobacteria isolates showed the highest antibiotic resistance against ampicillin (66%), cephalothin (57%), amoxicillin–clavulanic acid (33%), cefoxitin (31%), tetracycline (9%), nalidixic acid (7%), trimethoprim (6%), and kanamycin (5%). Three isolates showed intermediate resistance to the clinically important antibiotic imipenem. Escherichia coli isolated from lettuce exhibited multidrug resistance against five antibiotics. Fifteen isolates were confirmed to have AmpC β-lactamase, using the inhibitor-based test and the antagonism test; the latter test confirmed that the enzyme was an inducible type. Four types of ampC β-lactamase genes (CIT, EBC, FOX, and MOX) were detected in eight isolates: four Enterobacter cloacae isolates and one isolate each of Citrobacter freundii, Enterobacter asburiae, Enterobacter hormaechei, and Enterobacter ludwigii. It was concluded that fresh fruits and vegetables might play a role as a source or vehicle for transferring antibiotic-resistant bacteria that might spread to other countries through exportation. The clinically significant AmpC β-lactamase was rarely documented in the literature on bacteria isolated from fruits and vegetables, and to our knowledge, this is the first report on the detection of an inducible type in such commodities.

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Antimicrobial resistance in bacteria isolated from pigs with respiratory clinical signs in Brazil

Brazilian Journal of Veterinary Research and Animal Science ◽

10.11606/issn.1678-4456.bjvras.2020.160956 ◽

2020 ◽

Vol 57 (1) ◽

pp. e160956

Author(s):

Maysa Serpa ◽

Juliana Amália Fonte Bôa do Nascimento ◽

Mirian Fátima Alves ◽

Maria Isabel Maldonado Coelho Guedes ◽

Adrienny Trindade Reis ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Antimicrobial Agents ◽

Clinical Signs ◽

Multidrug Resistant ◽

Diffusion Method ◽

Great Level ◽

Respiratory Pathogens ◽

Bacterial Strains ◽

Disk Diffusion Method ◽

Pig Farms

Antimicrobial resistance is a current and important issue to public health, and it is usually associated with the indiscriminate use of antimicrobials in animal production. This study aimed to evaluate the antimicrobial susceptibility profile in bacterial isolates from pigs with clinical respiratory signs in Brazil. One hundred sixty bacterial strains isolated from pigs from 51 pig farms in Brazil were studied. In vitro disk-diffusion method was employed using 14 antimicrobial agents: amoxicillin, penicillin, ceftiofur, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, oxytetracycline, tetracycline, erythromycin, tilmicosin, florfenicol, lincomycin, and sulfadiazine/trimethoprim. The majority of isolates were resistant to at least one antimicrobial agent (98.75%; 158/160), while 31.25% (50/160) of the strains were multidrug resistant. Streptococcus suis and Bordetella bronchiseptica were the pathogens that showed higher resistance levels. Haemophilus parasuis showed high resistance levels to sulfadiazine/trimethoprim (9/18=50%). We observed that isolates from the midwestern and southern regions exhibited four times greater chance of being multidrug resistant than the isolates from the southeastern region studied. Overall, the results of the present study showed a great level of resistance to lincomycin, erythromycin, sulfadiazine/trimethoprim, and tetracycline among bacterial respiratory pathogens isolated from pigs in Brazil. The high levels of antimicrobial resistance in swine respiratory bacterial pathogens highlight the need for the proper use of antimicrobials in Brazilian pig farms.

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Prevalence and clonal relatedness of NDM and OXA-48-producing Klebsiella pneumoniae in a tertiary care hospital in South India

Journal of Laboratory Physicians ◽

10.4103/jlp.jlp_111_19 ◽

2019 ◽

Vol 11 (04) ◽

pp. 312-316

Author(s):

Poothakuzhiyil Remya ◽

Mariappan Shanthi ◽

Uma Sekar

Keyword(s):

Klebsiella Pneumoniae ◽

Tertiary Care ◽

Multidrug Resistant ◽

Genomic Diversity ◽

Major Type ◽

Care Hospital ◽

Clonal Relatedness ◽

Genes Encoding ◽

Clinically Significant ◽

Pfge Profiles

Abstract BACKGROUND: Carbapenems are used for the treatment of serious infections caused by multidrug-resistant Klebsiella pneumoniae. Resistance to carbapenems in K. pneumoniae is mainly due to metallo-beta-lactamases (NDM, IMP, and VIM) and class D oxacillinase (OXA-48-like). AIM AND OBJECTIVE: This study was undertaken to detect the genes encoding for carbapenemase in K. pneumoniae and to determine the clonal relatedness of selected isolates of K. pneumoniae producing NDM and OXA-48 by pulsed-field gel electrophoresis method (PFGE). MATERIALS AND METHODS: The isolates were collected over a period of 1 year. A total of 370 clinically significant, nonduplicate isolates of K. pneumoniae were included in this study. Phenotypic tests for the detection of carbapenemases were performed for all the isolates. Polymerase chain reaction (PCR) was carried out for the detection of carbapenemase genes such as blaKPC, blaIMP, blaVIM,blaNDM, and blaOXA-48. PFGE was performed, and the PFGE profiles were analyzed and compared using BioNumerics version 7.6. RESULTS: Of the 370 isolates of K. pneumoniae, carbapenemase genes were detected in 13.78% (51/370). blaOXA-48was the prevalent gene detected followed by blaNDMand blaKPC. Thirty strains of K. pneumoniae selected by PFGE analysis were divided into five clusters (A, B, C, D, and E). Cluster C was the major type detected carrying blaNDMand blaOXA-48genes.CONCLUSION:blaOXA-48was the most prevalent gene detected in this study. PCR is useful in detecting carbapenemase genes, especially blaNDM, which may show false susceptibility to carbapenems. There was no direct correlation detected between PFGE profiles and antibiotic susceptibility pattern. PFGE has revealed the genomic diversity among isolates, thereby suggesting heterogeneity in strain circulation within intensive care unit and wards of the hospital. Monitoring and molecular typing is essential to curtail the spread of multidrug-resistant strains and control the outbreaks of infection.

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Distribution of genes encoding adhesins and biofilm formation capacity among Uropathogenic Escherichia coli isolates in relation to the antimicrobial resistance

African Health Sciences ◽

10.4314/ahs.v20i1.29 ◽

2020 ◽

Vol 20 (1) ◽

pp. 238-247

Author(s):

Ashraf A Kadry ◽

Nour M Al-Kashef ◽

Amira M El-Ganiny

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Antimicrobial Resistance ◽

Biofilm Formation ◽

Critical Role ◽

Uropathogenic Escherichia Coli ◽

Diffusion Method ◽

Esbl Production ◽

Microtitre Plate Assay ◽

Genes Encoding

Background: Escherichia coli is the most predominant pathogen involved in UTIs. Mainly, fimbrial surface appendages are impli- cated in adherence to urothelium besides non-fimbrial proteins. Objectives: To determine prevalence of genes encoding fimbrial and non-fimbrial proteins among Uropathogenic Escherichia coli (UPEC). Furthermore, distribution of these genes and biofilm formation capacity were investigated in relation to antimicrobial resistance. Methods: Antimicrobial susceptibility of 112 UPEC isolates was performed using disc diffusion method. ESBL production was confirmed by double disc synergy test. Genes encoding fimbrial and non-fimbrial proteins were detected using PCR and biofilm formation was investigated using microtitre plate assay. Results: UPEC isolates exhibited high resistance against doxycyclines (88.39 %), β-lactams (7.14-86.6%), sulphamethoxaz- ole–trimethoprim (53.75%) and fluoro-quinolones (50%). Fifty percent of tested isolates were ESBL producers. PapGII gene was statistically more prevalent among pyelonephritis isolates. SfaS, focG and picU genes were statistically associated with flu- oro-quinolone (FQs) sensitive isolates and Dr/afaBC gene was statistically associated with ESBL production. Moreover, non- MDR isolates produced sturdier biofilm. Conclusion: PapGII adhesin variant seems to have a critical role in colonization of upper urinary tract. There is a possible link between antimicrobial resistance and virulence being capable of affecting the distribution of some genes besides its negative impact on biofilm formation. Keywords: Urinary tract infection; Escherichia coli; UPEC; adhesin genes; ESBL; biofilm.

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Multiple-Antibiotic Resistance of Enterococcus faecalis and Enterococcus faecium from Cecal Contents in Broiler Chicken and Turkey Flocks Slaughtered in Canada and Plasmid Colocalization of tetO and ermB Genes

Journal of Food Protection ◽

10.4315/0362-028x.jfp-10-451 ◽

2011 ◽

Vol 74 (10) ◽

pp. 1639-1648 ◽

Cited By ~ 33

Author(s):

CINDY-LOVE TREMBLAY ◽

ANN LETELLIER ◽

SYLVAIN QUESSY ◽

MARTINE BOULIANNE ◽

DANIELLE DAIGNAULT ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Enterococcus Faecalis ◽

Resistance Genes ◽

Enterococcus Faecium ◽

Broiler Chicken ◽

Multidrug Resistant ◽

Poultry Meat ◽

Antimicrobial Resistance Genes ◽

High Level ◽

Level Resistance

This study was conducted to characterize the antimicrobial resistance determinants and investigate plasmid colocalization of tetracycline and macrolide genes in Enterococcus faecalis and Enterococcus faecium from broiler chicken and turkey flocks in Canada. A total of 387 E. faecalis and E. faecium isolates were recovered from poultry cecal contents from five processing plants. The percentages of resistant E. faecalis and E. faecium isolates, respectively, were 88.1 and 94% to bacitracin, 0 and 0.9% to chloramphenicol, 0.7 and 14.5% to ciprofloxacin, 72.6 and 80.3% to erythromycin, 3.7 and 41% to flavomycin, 9.6 and 4.3% (high-level resistance) to gentamicin, 25.2 and 17.1% (high-level resistance) to kanamycin, 100 and 94% to lincomycin, 0 and 0% to linezolid, 2.6 and 20.5% to nitrofurantoin, 3 and 27.4% to penicillin, 98.5 and 89.7% to quinupristin-dalfopristin, 7 and 12.8% to salinomycin, 46.7 and 38.5% (high-level resistance) to streptomycin, 95.6 and 89.7% to tetracycline, 73 and 75.2% to tylosin, and 0 and 0% to vancomycin. One predominant multidrug-resistant phenotypic pattern was identified in both E. faecalis and E. faecium (bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, tetracycline, and tylosin). These isolates were further examined by PCR and sequencing for the genes encoding their antimicrobial resistance. Various combinations of vatD, vatE, bcrR, bcrA, bcrB, bcrD, ermB, msrC, linB, tetM, and tetO genes were detected, and ermB, tetM, and bcrB were the most common antimicrobial resistance genes identified. For the first time, plasmid extraction and hybridization revealed colocalization of tetO and ermB genes on a ca. 11-kb plasmid in E. faecalis isolates, and filter mating experiments demonstrated its transferability. Results indicate that the intestinal enterococci of healthy poultry, which can contaminate poultry meat at slaughter, could be a reservoir for quinupristin-dalfopristin, bacitracin, tetracycline, and macrolide resistance genes.

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