Heterogeneity of Macrolide-Lincosamide-Streptogramin B Resistance Phenotypes in Enterococci

ABSTRACT We determined the macrolide resistance phenotypes of 241 clinical isolates of erythromycin-resistant enterococci (MICs, ≥1 μg/ml), including 147 Enterococcus faecalis strains and 94 Enterococcus faecium strains, collected from a hospital in Seoul, Korea, between 1999 and 2000. By the erythromycin (40 μg)-josamycin (100 μg) double-disk test, 93 strains were assigned to the constitutive macrolide, lincosamide, and streptogramin B (MLSB) resistance (cMLSB) phenotype, and the remaining 148 strains were assigned to the inducible MLSB resistance (iMLSB) phenotype. Of the strains with the iMLSB phenotype, 36 exhibited a reversibly inducible MLSB (riMLSB) phenotype, i.e., blunting of the erythromycin zone of inhibition, which indicates that the 16-membered-ring macrolide josamycin is a more effective inducer than the 14-membered-ring macrolide erythromycin. Sequence analysis of the regulatory regions of the erm(B) genes from all of the strains exhibiting the riMLSB phenotype revealed not only erm(Bv) [where v represents variant; previously erm(AMR)] (n = 13), as reported previously, but also three kinds of erm(B) variants, which were designated erm(Bv1) (n = 17), erm(Bv2) (n = 3), and erm(Bv3) (n = 3), respectively. In lacZ reporter gene assays of these variants, the 16-membered-ring macrolide tylosin had stronger inducibility than erythromycin at ≥0.1 μg/ml. These findings highlight the versatility of erm(B) in induction specificity.

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P116 Enterococcus faecalis and Enterococcus faecium clinical isolates carrying the vanA gene but susceptible to vancomycin

International Journal of Antimicrobial Agents ◽

10.1016/s0924-8579(13)70360-1 ◽

2013 ◽

Vol 42 ◽

pp. S78

Author(s):

I.K. Bae ◽

H. Lee ◽

W. Song ◽

S.H. Jeong ◽

D. Yong ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Clinical Isolates ◽

Vana Gene

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Susceptibility testing of clinical isolates of Enterococcus faecium and Enterococcus faecalis.

Journal of Clinical Microbiology ◽

10.1128/jcm.30.1.41-45.1992 ◽

1992 ◽

Vol 30 (1) ◽

pp. 41-45 ◽

Cited By ~ 16

Author(s):

M Louie ◽

A E Simor ◽

S Szeto ◽

M Patel ◽

B Kreiswirth ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Susceptibility Testing ◽

Clinical Isolates

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Distribution of aminoglycoside resistance genes in recent clinical isolates of Enterococcus faecalis, Enterococcus faecium and Enterococcus avium

Epidemiology and Infection ◽

10.1017/s0950268801005271 ◽

2001 ◽

Vol 126 (2) ◽

pp. 197-204 ◽

Cited By ~ 61

Author(s):

N. KOBAYASHI ◽

MD. MAHBUB ALAM ◽

Y. NISHIMOTO ◽

S. URASAWA ◽

N. UEHARA ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Clinical Isolates ◽

University Hospital ◽

Aminoglycoside Resistance ◽

Genes Encoding ◽

Enterococcal Species ◽

Aminoglycoside Resistance Genes ◽

Major Factors ◽

High Level

Aminoglycoside modifying enzymes (AMEs) are major factors which confer aminoglycoside resistance on bacteria. Distribution of genes encoding seven AMEs was investigated by multiplex PCR for 279 recent clinical isolates of enterococci derived from a university hospital in Japan. The aac(6′)-aph(2″), which is related to high level gentamicin resistance, was detected at higher frequency in Enterococcus faecalis (42·5 %) than in Enterococcus faecium (4·3 %). Almost half of E. faecalis and E. faecium isolates possessed ant(6)-Ia and aph(3′)-IIIa. The profile of AME gene(s) detected most frequently in individual strains of E. faecalis was aac(6′)-aph(2″)+ant(6)-Ia+aph(3′)-IIIa, and isolates with this profile showed high level resistance to both gentamicin and streptomycin. In contrast, AME gene profiles of aac(6′)-Ii+ant(6)-Ia+aph(3′)-IIIa, followed by aac(6′)-Ii alone, were predominant in E. faecium. Only one AME gene profile of ant(6)-Ia+aph(3′)-IIIa was found in Enterococcus avium. The ant(4′)-Ia and ant(9)-Ia, which have been known to be distributed mostly among Staphylococcus aureus strains, were detected in a few enterococcal strains. An AME gene aph(2″)-Ic was not detected in any isolates of the three enterococcal species. These findings indicated a variety of distribution profiles of AME genes among enterococci in our study site.

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Comparative In Vitro Activities and Postantibiotic Effects of the Oxazolidinone Compounds Eperezolid (PNU-100592) and Linezolid (PNU-100766) versus Vancomycin against Staphylococcus aureus, Coagulase-Negative Staphylococci, Enterococcus faecalis, and Enterococcus faecium

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.3.721 ◽

1998 ◽

Vol 42 (3) ◽

pp. 721-724 ◽

Cited By ~ 54

Author(s):

Michael J. Rybak ◽

Diane M. Cappelletty ◽

Tabitha Moldovan ◽

Jeffrey R. Aeschlimann ◽

Glenn W. Kaatz

Keyword(s):

Staphylococcus Aureus ◽

Enterococcus Faecalis ◽

Inhibitory Activity ◽

Enterococcus Faecium ◽

Antibacterial Agents ◽

Clinical Isolates ◽

Postantibiotic Effect ◽

Coagulase Negative Staphylococci ◽

Time Kill

ABSTRACT The activities of the oxazolidinone antibacterial agents eperezolid (PNU-100592) and linezolid (PNU-100766) were compared with that of vancomycin against clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus (n = 200), coagulase-negative staphylococci (n = 100), and vancomycin-susceptible and -resistant Enterococcus faecalisand Enterococcus faecium (n = 50). Eperezolid and linezolid demonstrated good in vitro inhibitory activity, regardless of methicillin susceptibility for staphylococci (MIC at which 90% of the isolates are inhibited [MIC90] range, 1 to 4 μg/ml) or vancomycin susceptibility for enterococci (MIC90 range, 1 to 4 μg/ml). In time-kill studies, eperezolid and linezolid were bacteriostatic in action. A postantibiotic effect of 0.8 ± 0.5 h was demonstrated for both eperezolid and linezolid against S. aureus, S. epidermidis, E. faecalis, and E. faecium.

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VanD-Type Vancomycin-Resistant Enterococcus faecium and Enterococcus faecalis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.10.3892-3904.2004 ◽

2004 ◽

Vol 48 (10) ◽

pp. 3892-3904 ◽

Cited By ~ 39

Author(s):

Florence Depardieu ◽

Mathias Kolbert ◽

Hendrik Pruul ◽

Jan Bell ◽

Patrice Courvalin

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Housekeeping Gene ◽

Clinical Isolates ◽

Penicillin G ◽

Conserved Residues ◽

Constitutive Resistance ◽

Vancomycin Resistant ◽

Low Levels ◽

Type Strains

ABSTRACT Enterococcus faecium clinical isolates A902 and BM4538, which were resistant to relatively high levels of vancomycin (128 and 64 μg/ml, respectively) and to low levels of teicoplanin (4 μg/ml), and Enterococcus faecalis clinical isolates BM4539 and BM4540, which were resistant to moderate levels of vancomycin (16 μg/ml) and susceptible to teicoplanin (0.25 μg/ml), were studied. They were constitutively resistant by synthesis of peptidoglycan precursors ending with d-alanyl-d-lactate and harbored a chromosomal vanD gene cluster which was not transferable by conjugation to other enterococci. VanXD activity, which is not required in the absence of d-Ala-d-Ala, was low in the four strains, although none of the conserved residues was mutated; and the constitutive VanYD activity in the membrane fractions was inhibited by penicillin G. The mutations E13G in the region of d-alanine:d-alanine ligase (which is implicated in d-Ala1 binding in A902) and S319N of the serine involved in ATP binding in BM4538 and a 7-bp insertion at different locations in BM4539 and BM4540 (which led to putative truncated proteins) led to the production of an impaired enzyme and accounted for the lack of d-Ala-d-Ala-containing peptidoglycan precursors. The same 7-bp insertion in vanSD of BM4539 and BM4540 and a 1-bp deletion in vanSD of A902, which in each case led to a putative truncated and presumably nonfunctional protein, could account for the constitutive resistance. Strain BM4538, with a functional VanSD, had a G140E mutation in VanRD that could be responsible for constitutive glycopeptide resistance. This would represent the first example of constitutive van gene expression due to a mutation in the structural gene for a VanR transcriptional activator. Study of these four additional strains that could be distinguished on the basis of their various assortments of mutations confirmed that all VanD-type strains isolated so far have mutations in the ddl housekeeping gene and in the acquired vanSD or vanRD gene that lead to constitutive resistance to vancomycin.

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Trends in antimicrobial resistance of clinical isolates of Enterococcus faecalis and Enterococcus faecium in Greece between 2002 and 2007

Journal of Hospital Infection ◽

10.1016/j.jhin.2009.12.007 ◽

2010 ◽

Vol 75 (3) ◽

pp. 225-227 ◽

Cited By ~ 23

Author(s):

E. Protonotariou ◽

E. Dimitroulia ◽

S. Pournaras ◽

V. Pitiriga ◽

D. Sofianou ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Clinical Isolates

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PREVALENCE OF VIRULENCE FACTORS AMONG CLINICAL ISOLATES OF ENTEROCOCCUS SPP.

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2016.v9s3.14644 ◽

2016 ◽

Vol 9 (9) ◽

pp. 72 ◽

Cited By ~ 1

Author(s):

Umadevi Sivaraman ◽

Ravichandran L ◽

Pramodhini S ◽

Srirangaraj S ◽

Seetha Ks

Keyword(s):

Enterococcus Faecalis ◽

Virulence Factors ◽

Enterococcus Faecium ◽

Sheep Blood Agar ◽

Clinical Isolates ◽

Blood Agar ◽

Sheep Blood ◽

Biofilm Production ◽

Enterococcus Spp

ABSTRACTObjective: To identify some of the virulence factors such as hemolysin, gelatinase, and biofilm production among the clinical isolates of enterococci.Methods: Hemolysin detection using sheep blood agar. Gelatine agar was used for gelatinase production, and tube adherence method was used fordetecting biofilm production.Results: Hemolysin production observed in 49% of isolates, gelatinase production in 41% of isolates, and 46% of isolates were produced biofilm.Conclusion: Virulence factors production was noticed more in Enterococcus faecalis than Enterococcus faecium. It is necessary to find theproduction of important virulence factors among the clinical isolates as they are always associated with virulence of the organism including drugresistance.Keywords: Hemolysin, Gelatinase, Biofilm, Enterococcus.

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Gene Dosage and Linezolid Resistance in Enterococcus faecium and Enterococcus faecalis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.46.10.3334-3336.2002 ◽

2002 ◽

Vol 46 (10) ◽

pp. 3334-3336 ◽

Cited By ~ 175

Author(s):

S. H. Marshall ◽

C. J. Donskey ◽

R. Hutton-Thomas ◽

R. A. Salata ◽

L. B. Rice

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Gene Dosage ◽

Clinical Isolates ◽

Rrna Genes ◽

23S Rrna ◽

Linezolid Resistance ◽

Clear Association ◽

23S Rrna Genes ◽

Domain V

ABSTRACT Resistance to linezolid has been associated with a G2576U mutation in domain V of the 23S rRNA. We analyzed nine clinical isolates of linezolid-resistant enterococci and showed a clear association between the number of 23S rRNA genes containing this mutation and the level of linezolid resistance expressed.

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