Antimicrobial Agents and Chemotherapy, December 1999, p. 2823-2830, Vol. 43, No. 12
Nomenclature for Macrolide and
Macrolide-Lincosamide-Streptogramin B Resistance Determinants
Department of Pathobiology, University of
Washington, Seattle, Washington 981951;
Department of Infectious Diseases, Pfizer Central Research,
Groton, Connecticut 06340-15962; Unite
des Agents Antibacterienes, Institute Pasteur, Paris Cedex 15, France3; Danish Veterinary Laboratory,
DK-1790 Copenhagen, Denmark4;
Department of Microbiology, Monash University, Clayton,
Victoria 3168, Australia5; and
Antimicrobial Research Laboratory, National Public Health
Institute, FIN-20520 Turku, Finland6
Macrolides are composed of
14 (erythromycin and clarithromycin)-, 15 (azithromycin)-, or 16 (josamycin, spiramycin, and tylosin)-membered lactones to which are
attached amino and/or neutral sugars via glycosidic bonds.
Erythromycin was introduced in 1952 as the first macrolide antibiotic.
Unfortunately, within a year, erythromycin-resistant (Emr)
staphylococci from the United States, Europe, and Japan were described
(101). Erythromycin is produced by
Saccharopolyspora erythraea, while the newer
macrolides are semisynthetic molecules with substitutions on the
lactone. The newer derivatives, such as clarithromycin and
azithromycin, have improved intracellular and tissue penetration, are
more stable, are better absorbed, have a lower incidence of
gastrointestinal side effects, and are less likely to interact with
other drugs. They are useable against a wider range of infectious
bacteria, such as Legionella, Chlamydia, Haemophilus, and some Mycobacterium species (not
M. tuberculosis), and their pharmacokinetics provide
for less frequent dosing than erythromycin (21, 47, 96,
97). As a result, the usage of the newer macrolides has increased
dramatically over the last few years, which has led to increased
exposure of bacterial populations to macrolides (101-103,
107).
Macrolides inhibit protein synthesis by stimulating dissociation of the
peptidyl-tRNA molecule from the ribosomes during elongation (101,
103). This results in chain termination and a reversible stoppage
of protein synthesis. The first mechanism of macrolide resistance
described was due to posttranscriptional modification of the 23S rRNA
by the adenine-N6 methyltransferase
(101-103). These enzymes add one or two methyl groups to a
single adenine (A2058 in Escherichia coli) in the 23S rRNA
moiety. Over the last 30 years, a number of
adenine-N6-methyltransferases from different
species, genera, and isolates have been described. In general, genes
encoding these methylases have been designated erm
(erythromycin ribosome methylation), although there are exceptions,
especially in the antibiotic-producing organisms (see Tables 1 and 3)
(103). As the number of erm genes described has
grown, the nomenclature for these genes has varied and has been
inconsistent (Table 1).
In some cases, unrelated genes have been given the same letter
designation, while in other cases, highly related genes (>90%
identity) have been given different names.
0066-4804/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
MINIREVIEW
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INTRODUCTION
Top
Introduction
Conclusion
References
TABLE 1.
rRNA methylase genes involved in
MLSB resistance
The binding site in the 50S ribosomal subunit for erythromycin
overlaps the binding site of the newer macrolides, as well as the
structurally unrelated lincosamides and streptogramin B antibiotics.
The modification by methylase(s) reduces the binding of all three
classes of antibiotics, which results in resistance against macrolides,
lincosamides, and streptogramin B antibiotics (MLSB).
The rRNA methylases are the best studied among macrolide resistance
mechanisms (47, 101-103). However, a variety of other mechanisms have been described which also confer resistance (Table 2). Many of these
alternative mechanisms of resistance confer resistance to only one or
two of the antibiotic classes of the MLSB complex.
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In this review, we suggest a new nomenclature for naming MLS genes and
propose to use the rules developed for identifying and naming new
tetracycline resistance genes (51, 52). This system, with a
few recent modifications, was originally designed because of the
ability of two genes to be distinguished uniquely by DNA-DNA probe
methodology (51). It was generally found that two genes with
<80% amino acid sequence identity provided enough variability in
nucleotide sequence to permit distinct probes to be designed. Although
many investigators are likely to sequence new genes, the use of probe
technology allows rapid identification of isolates containing
potentially new genes, as well as a reliable way to screen populations
and determine the frequency of any one resistant determinant.
Therefore, we continued this paradigm by assigning two genes of
80%
amino acid identity to the same class and same letter designation,
while two genes that show
79% amino acid identity are given a
different letter designation. Table 1 shows the results of the
classification, with some classes having members with little
variability, while others, like classes A and O, show a greater range
of homology at both the DNA and amino acid levels. As new gene
sequences emerge, ideally they will need to be compared by
oligonucleotide probe hybridization and/or sequence analysis against
the bank of known genes before a new designation is assigned. If
multiple genes are available in any one class, especially when there is
a range as in class A, then all representative members of the class
should be examined, not just one. To confirm that the proposed name or
number for the newly discovered resistance determinant has not
been used by another investigator, please contact M. C. Roberts
for this information. A similar request has been made for new
tet genes (52).
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RRNA METHYLASES |
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Over the last 30 years, a large number of different rRNA methylase
genes (erm) have been isolated from a variety of bacteria that range from E. coli to Haemophilus influenzae
in gram-negative species and from Streptococcus pneumoniae
to Corynebacterium spp. in gram-positive species (Table
3). In addition, a
variety of gram-positive and gram-negative anaerobes, and even
spirochetes such as Borrelia burgdorferi and Treponema
denticola, have all been shown to carry erm genes
(Table 3) (36, 77, 78). All erm enzymes methylate
the same adenine residue, resulting in an MLSB phenotype
(9, 100-103). This adenine (A2058) or one of the adjacent
residues in the peptidyltransferase region (A2057 or A2059) is
changed to another nucleotide by mutation in
macrolide-resistant Mycobacterium intracellulare,
Mycobacterium avium, Propionibacterium spp., and
Helicobacter pylori (58, 84, 100-103).
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Differences between the various erm genes are seen in the regulation of expression of the phenotype. Some of the enzymes are inducibly regulated by translational attenuation of a mRNA leader sequence; in the absence of erythromycin, the mRNA is in an inactive conformation due to a sequestered Shine-Dalgarno sequence, preventing efficient initiation of translation of the erm transcripts. Mutational analyses of the erm(C) leader peptide suggested that the peptide, (FS)IFVI, is critical for induction (103). However, when the erm peptides from the erm genes are compared, little sequence similarity is apparent (103). Recently, a second mechanism of regulation has been described in which the lack of erythromycin prevents the complete synthesis of the mRNA due to rho factor-independent termination. This type of regulation has been described for the erm(K) system (20), and by homology, we hypothesize that it may also exist for erm(D), as well as erm(J), because they are highly related and have been grouped together under class D (Table 1). In either system, inducible isolates, when tested, may appear to be susceptible or intermediately resistant to macrolides and susceptible to lincosamides. Erythromycin is generally a good inducer in most species; in animal or human streptococcal isolates, lincosamides and/or streptogramin B may be good inducers (47, 76). Good overviews of regulation of the erm genes can be found in recent reviews by Weisblum (100-103).
Inducible strains predominated in the 1960s to 1970s. However, today it is more common in many geographical areas to find isolates that constitutively produce the rRNA methylase without preexposure to antibiotics. Constitutive erm gene expression is usually associated with structural alterations in the erm translational attenuator, including deletions, duplications, and point mutations in erm(C) (104). They can be distinguished from inducible isolates by the stable MICs for them regardless of whether they are pregrown with or without an inducer (76, 102).
Many of the erm genes are associated with conjugative or
nonconjugative transposons which tend to reside on the chromosomes, although some have been found in plasmids. They are often associated with other antibiotic resistance genes, especially tetracycline resistance genes. The erm(F) gene is often linked with the
tet(Q) gene, while the erm(B) gene is often
linked with the tet(M) gene (24, 86, 95). These
conjugative transposons can have a wide host range, which may explain
why clinical isolates of many different bacterial species have been
found to carry these erm genes (Table 3). The erm
genes in general have low G+C contents (31 to 34%), while the overall
chromosomal G+C contents found in gram-negative species are
50% and
~35% in gram-positive species.
It has been common practice for investigators to give their
erm gene a new name regardless of the DNA and predicted
amino acid sequence similarity to previously characterized
erm genes and without regard to whether the gene resides in
a different isolate, species, or genus. The result has been that, over
the years, the names of these erm genes have become
confusing, and often a complex table is required to remember which
genes are closely related (Table 1). In the worst cases, genes for
unrelated enzymes have been given the same name (erm(A),
causing confusion in the literature and GenBank listings (Table 1). The
opposite also has occurred where very closely related or virtually
identical enzymes have been given a variety of different names. For
example, erm(F) (GenBank no. M14730) is found on the
Bacteroides transposons Tn4351 and
Tn4000 (71), erm(FS) (no. M17808) is
on Bacteroides transposon Tn4551 (91),
and erm(FU) (no. M62487) (32) is also from
Bacteriodes. All three enzymes share
97% DNA and amino acid identity (Table 1). Since there are no phenotypic differences between the three erm(F) genes and distinguishing them by
any method other than sequencing is problematic, we propose that all three should be known as class F: the Erm(F) protein and the
erm(F) gene (Table 1).
The situation is even worse with class B, which is composed of a larger
number of genes, including erm(AM), erm(B),
erm(BC), erm(BP), and erm(Z),
whose sequences share
98% homology (Table 1). Because the
normal gene designation is to use a single letter (26) and
the possibility of confusion between erm(A) and
erm(AM), we propose that this group be known as class B: the
erm(B) genes and the Erm(B) protein (Table 1). Recent
dendrograms of many of the erm genes can be found in
articles by Seppälä et al. (88) and Matsuoka et
al. (56) and support this grouping of all of these genes
within the class B designation.
To help those in the field, GenBank numbers or references for sequences
that have not been deposited are listed in Table 1. If a new gene
sequence shows
80% amino acid homology to any member of a gene class
and confers a similar phenotype to the host, we propose that the new
gene be placed in the existing group and not be given a new letter or
number designation. Thus, with classes that show a wide range of
homologies, like class A (81% amino acid homology) or class O (84%
amino acid homology), multiple members must be compared to the new
gene. Note that the class designation is based on the amino acid
sequence of the structural gene only and does not include the various
regulatory sequences that can occur upstream of the gene. These
guidelines are intended to apply to all of the
N-methyltransferases, regardless of whether the gene was
originally identified in pathogenic, opportunistic, normal flora
bacteria or an antibiotic-producing species. Once all of the single
capital letters have been used to identify new erm genes, we
recommend naming genes as follows: erm(30),
erm(31), etc. This system has been proposed for naming
of new tet genes [tet(30), etc.]
(52). Furthermore, a similar set of guidelines should be
adopted for the genes that encode other mechanisms of resistance to any
of the MLS antibiotics (Table 1). Class Y for gene erm(GM),
class S for gene erm(SF), class T for gene
erm(GT), class V for gene erm(SV), class X for
genes erm(CD), erm(CX), and erm(A),
and class 2 for gene srm(D) are new class designations that
conform to the single-letter designation (Table 1).
There are a number of other methylase genes, most often found in methylase-producing organisms which have not been given erm designations, such as tlr(D), car(B), myr(B), and smr(A). All are from species which confer resistance to a 16-membered ring macrolide (Table 1). We have grouped and renamed them classes H for car(B), I for mdm(A), N for tlr(D), O for genes lrm and srm(A), U for lmr(B), and W for myr(B). The clr gene could not be classified, because there is no sequence in the database or literature available. Less work has been done to determine if these genes are found outside their respective antibiotic producers (Table 3). erm genes are often linked with tet genes, and since genes conferring resistance to oxytetracycline, originally found in antibiotic-producing streptomycetes, are now found in some clinical Mycobacterium isolates, it is certainly possible that some erm genes have also moved into Mycobacterium spp. and other genera (68).
To prevent two unrelated genes from being given the same designation, we propose to establish a reference center, as has recently been recommended for tetracycline resistance genes. By using the guideline presented above in governing the identification of new erm genes, surveys can be conducted in bacterial populations to examine the spread of particular MLSB-resistant determinants. A single internal DNA fragment or oligonucleotide probe or a PCR assay that detects all members of a gene class can be established to screen large numbers of isolates. Not only will the adoption of a uniform naming system reduce the number of new erm gene names, but it will hopefully prevent confusion over unrelated genes being given the same designation and also prevent highly related genes from having different gene designations.
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EFFLUX SYSTEMS |
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A number of different antibiotic resistance genes code for transport (efflux) proteins. These do not modify either the antibiotic or the antibiotic target, but instead pump the antibiotic out of the cell or the cellular membrane, keeping intracellular concentrations low and ribosomes free from antibiotic. Many of these proteins [mef(A), mef(E), and lmr(A)] have homology to the major facilitator superfamily (MFS) of efflux proteins. Others [car(A), msr(A), msr(B), ole(B), ole(C) srm(B), tlr(C), vga, and vga(B)] are putative members of the ABC transporter superfamily (70). In early years, most macrolide resistance was mediated by the presence of erm genes. However, more recently, other mechanisms of macrolide resistance have been found in increasing frequency in certain gram-positive populations (23, 27, 41, 43, 44, 92, 93, 106). Three different efflux systems which confer resistance have been described for gram-positive cocci [msr(A) (macrolide and streptogramin B resistant), mef(A) (macrolide efflux), and vga and vga(B) (virginiamycin factor A)] (4) (Table 2). Besides the academic interest in these genes, their presence in an erythromycin-resistant bacterial pathogen of interest may also have implications in terms of therapeutic choices. If an isolate carries a mef gene, clindamycin can be considered, whereas the presence of an erm(B) gene would preclude consideration of a lincosamide. Recently, we and others have identified Streptococcus pneumoniae strains which carry both mef and erm(B) genes and, as expected, have the MLSB phenotype (41, 53).
The mef genes have been found in a variety of gram-positive genera, including corynebacteria, enterococci, micrococci, and a variety of streptococcal species (30, 43, 53, 90) (Table 3), suggesting a much wider distribution of this group of genes than originally imagined. Many of these genes are associated with conjugative elements located in the chromosome and are readily transferred conjugally across species and genus barriers (43, 53).
Two mef genes have been characterized in the literature: mef(A) (23) and mef(E) (94). The mef(A) gene was described in Streptococcus pyogenes, while the mef(E) gene was found in S. pneumoniae. Since the two genes share 90% DNA and 91% amino acid homology (Table 2), we recommended that these two genes be considered a single class, A: mef(A) gene and Mef(A) protein (Table 2).
The msr(A), msr(SA), msr(SA)', and msr(B) group differs from the mef genes because they confer resistance to both macrolide and streptogramin B antibiotics (MS) (13, 55-57). The msr(B) gene is roughly half the size of msr(A), but very homologous to it. Though this gene is significantly shorter than the msr(A) gene sequence, we placed it with the other msr genes (Table 2).
In antibiotic producers, there are efflux pumps specific for MLSB antibiotics that generally belong to the ABC transporter superfamily (87). They include car(A) from Streptomyces thermotolerans (87), ole(B) from Streptomyces antibioticus (7, 80), srm(B) from Streptomyces ambofaciens (73), lmr(C) from Streptomyces lincolnensis (70), and tlr(C) from Streptomyces fradiae (87). In addition to the msr(A) efflux pumps, there are two efflux systems identified in staphylococci that confer resistance to streptogramin A antibiotics, vga and vga(B) (4). Besides mef(A), other efflux proteins that appear to be fueled by the proton motive force have been described for MLSB antibiotics. A lincomycin-specific efflux pump encoded by lmr(A) has been described in S. lincolnensis (110).
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OTHER MECHANISMS |
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A variety of other mechanisms which usually confer resistance to only one of the three classes (M, L, or S) or one component such as streptogramin A, but not streptogramin B, have been described (103) (Table 2). These proteins modify the antibiotic rather than the rRNA target or serve as pumps that shuttle the antibiotic out of the bacterial cell. Enzymes which hydrolyze streptogramin B [vgb (virginiamycin factor B hydrolase), vgb(B) genes] or modify the antibiotic by adding an acetyl group (acetyltransferases) to streptogramin A [vat (virginiamycin, factor A acetylation), vat(B), vat(C), sat(A), and sat(G) genes] have been described (1-6) (Table 2). Many of these genes are plasmid borne, and often these vat-related genes [vat, vat(B), and vat(C) genes] are downstream of other genes encoding resistance to streptogramins [vgb, vga(B), and vgb(B) genes, respectively] in staphylococci (2), but not in enterococci (72). The acetyltransferase genes are related, in the active site region, to a novel chloramphenicol acetyltransferase family of enzymes. We have renamed sat(A) as vat(D) and sat(G) as vat(E) to simplify the nomenclature (Table 2).
Unlike most of the other genes described in this review, both the ere (erythromycin esterification) and mph (macrolide phosphotransferase) genes (Table 2) were first described in E. coli rather than gram-positive cocci (8, 63, 64, 66, 67). According to our guidelines, mph(K) has been reassigned to mph(A), because there are only 10 amino acid (1%) differences between the two proteins. mph(BM) and mph(C) (66a) are grouped under Mph(C), because these genes are nearly identical to each other and distinct from mph(A) and mph(B) (Table 2). Several lincomycin nucleotidyltransferases have been identified: lin(A) in Staphylococcus haemolyticus (16), lin(A)' in Staphylococcus aureus (17), and lin(B) in Enterococcus faecium (14). We propose changing lin(A) and lin(B) to lnu(A) and lnu(B) (for lincomycin nucleotidyltransferase), because the former letters have already been used for gamma BHC dehydrochlorinase and cyclohexadiene hydrolase genes. It is suggested that prior to naming a new gene class, it is necessary to determine if the proposed three-letter designation has been used for other previously characterized genes.
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CONCLUSIONS |
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With the introduction of the newer, more stable macrolides with enhanced properties, there has been a significant increase in macrolide usage. Macrolides like azithromycin and clarithromycin are recommended for prophylactic use to prevent Mycobacterium avium complex disease in human immunodeficiency virus patients. As macrolide use increases, so does its exposure to bacterial populations, increasing the opportunity for bacteria to acquire macrolide or MLS resistance. Given that intragenic transfer of macrolide-resistant determinants is possible (15), it is likely that all of the genes described in this review will spread into new species and that new genes will be identified. Therefore, it is important to clarify the nomenclature of these resistance genes for their expanding audience.
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ACKNOWLEDGMENTS |
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We thank M. Matsuoka for providing unpublished material; B. Weisblum for discussions; J. Davies, C. J. Smith, and S. Schwarz for reading the manuscript; and S. Lerner for doing sequence comparisons.
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FOOTNOTES |
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* Corresponding author. Mailing address: Department of Pathobiology, Box 357238, University of Washington, Seattle, WA 98195. Phone: (206) 543-8001. Fax: (206) 543-3873. E-mail: marilynr{at}u.washington.edu.
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REFERENCES |
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|
|
|---|
| 1. | Allignet, J., and N. El Solh. 1995. Diversity among the gram-positive acetyltransferases inactivating streptogramin A and structurally related compounds and characterization of a new staphylococcal determinant, vatB. Antimicrob. Agents Chemother. 39:2027-2036[Abstract]. |
| 2. |
Allignet, J.,
N. Liassine, and N. El Solh.
1998.
Characterization of a staphylococcal plasmid related to pUB110 and carrying two novel genes, vatC and vgbB, encoding resistance to streptogramins A and B and similar antibiotics.
Antimicrob. Agents Chemother.
42:1794-1798 |
| 3. | Allignet, J., V. Loncle, C. Simenel, M. Delepierre, and N. El Solh. 1993. Sequence of a staphylococcal gene, vat, encoding an acetyltransferase inactivating the A-type compounds of virginiamycin-like antibiotics. Gene 130:91-98[Medline]. |
| 4. | Allignet, J., V. Loncle, and N. El Solh. 1992. Sequence of a staphylococcal plasmid gene, vga, encoding a putative ATP-binding protein involved in resistance to virginianmycin A-like antibiotics. Gene 117:45-51[Medline]. |
| 5. | Allignet, J., V. Loncle, P. Mazodier, and N. El Solh. 1988. Nucleotide sequence of a staphylococcal plasmid gene, vgb, encoding a hydrolase inactivating the B components of virginiamycin-like antibiotics. Plasmid 20:271-275[Medline]. |
| 6. | Allignet, J., and N. El Solh. 1995. Diversity among the gram-positive acetyltransferases inactivating streptogramin A and structurally related compounds and characterization of a new staphylococcal determinant, vatB. Antimicrob. Agents Chemother. 39:2027-2036. |
| 7. | Aparicio, G., A. Buche, C. Mendez, and J.-A. Salas. 1996. Characterization of the ATPase activity of the N-terminal nucleotide binding domain of an ABC transporter involved in oleandomycin secretion by Streptomyces antibioticus. FEMS Microbiol. Lett. 141:157-162[Medline]. |
| 8. |
Arthur, M.,
A. Andremont, and P. Courvalin.
1987.
Distribution of erythromycin esterase and rRNA methylase genes in members of the family Enterobacteriaceae highly resistant to erythromycin.
Antimicrob. Agents Chemother.
31:404-409 |
| 9. |
Arthur, M.,
A. Brisson-Noel, and P. Courvalin.
1987.
Origin and evolution of genes specifying resistance to macrolides, lincosamides and streptogramin antibiotics: data and hypothesis.
J. Antimicrob. Chemother.
20:783-802 |
| 10. |
Berryman, D. I., and J. I. Rood.
1989.
Cloning and hybridization analysis of ermP, a macrolide-lincosamide-streptogramin B resistance determinant from Clostridium perfringens.
Antimicrob. Agents Chemother.
33:1346-1353 |
| 11. |
Berryman, D. I., and J. I. Rood.
1995.
The closely related ermB-ermAM genes from Clostridium perfringens, Enterococcus faecalis (pAM 1), and Streptococcus agalactiae (pIP501) are flanked by variants of a directly repeated sequence.
Antimicrob. Agents Chemother.
39:1830-1834[Abstract].
|
| 12. |
Berryman, D. I.,
M. Lyristis, and J. I. Rood.
1994.
Cloning and sequence analysis of ermQ, the predominant macrolide-lincosamide-streptogramin B resistance gene in Clostridium perfringens.
Antimicrob. Agents Chemother.
38:1041-1046 |
| 13. | Beyer, D., and K. Pepper. 1998. The streptogramin antibiotics: update on their mechanism of action. Exp. Opin. Investig. Drugs 7:591-599. |
| 14. |
Bozdogan, B.,
L. Berrezouga,
M.-S. Kuo,
D. A. Yurek,
K. A. Farley,
B. J. Stockman, and R. LeClercq.
1999.
A new resistance gene, linB, conferring resistance to lincosamides by nucleotidylation in Enterococcus faecium HM1025.
Antimicrob. Agents Chemother.
43:925-929 |
| 15. |
Brisson-Noël, A.,
M. Arthur, and P. Courvalin.
1988.
Evidence for natural gene transfer from gram-positive cocci to Escherichia coli.
J. Bacteriol.
170:1739-1745 |
| 16. | Brisson-Noel, A., and P. Courvalin. 1986. Nucleotide sequence of gene linA encoding resistance to lincosamides in Staphylococcus haemolyticus. Gene 43:247-253[Medline]. |
| 17. |
Brisson-Noel, A.,
P. Delrieu,
D. Samain, and P. Courvalin.
1988.
Inactivation of lincosaminide antibiotics in Staphylococcus. Identification of lincosaminide O-nucleotidyltransferases and comparison of the corresponding resistance genes.
J. Biol. Chem.
263:15880-15887 |
| 18. |
Calcutt, M. J., and E. Cundliffe.
1990.
Cloning of a lincosamide resistance determinant from Streptomyces caelestis, the producer of celesticetin, and characterization of the resistance mechanism.
J. Bacteriol.
172:4710-4714 |
| 19. | Cheng, J., T. Grebe, L. Wondrack, P. Courvalin, and J. Sutcliffe. 1999. Characterization of genes involved in erythromycin resistance in a clinical strain of Staphylococcus aureus, abstr. 837, p. 114. In Program and abstracts of the 39th Interscience Conference on Antimicrobial Agents and Chemotherapy. American Society for Microbiology, Washington, D.C. |
| 20. |
Choi, S.-S.,
S.-K. Kim,
T.-G. Oh, and E.-C. Choi.
1997.
Role of mRNA termination in regulation of ermK.
J. Bacteriol.
179:2065-2067 |
| 21. | Chu, D. 1995. Recent developments in 14- and 15-membered macrolides. Exp. Opin. Investig. Drugs 4:65-94. |
| 22. |
Chung, W. O.,
C. Werckenthin,
S. Schwarz, and M. C. Roberts.
1999.
Host range of the ermF rRNA methylase gene in human and animal bacteria.
J. Antimicrob. Chemother.
43:5-14 |
| 23. | Clancy, J., J. W. Petitpas, F. Dib-Hajj, W. Yuan, M. Cronan, A. Kamath, J. Bergeron, and J. Retsema. 1996. Molecular cloning and functional analysis of a novel macrolide-resistance determinant mefA from Streptococcus pyogenes. Mol. Microbiol. 22:867-879[Medline]. |
| 24. | Clewell, D. B., S. E. Flannagan, and D. D. Jaworski. 1995. Unconstrained bacterial promiscuity: the Tn916-Tn1545 family of conjugative transposons. Trends Microbiol. 3:229-236[Medline]. |
| 25. | Cooper, A. J., N. B. Shoemaker, and A. A. Salyers. 1996. The erythromycin resistance gene from the Bacteroides conjugal transposon Tcr Emr 7853 is nearly identical to ermG from Bacillus sphaericus. Antimicrob. Agents Chemother. 40:506-508[Abstract]. |
| 26. | Council of Biology Editors, Inc. 1983. CBE style manual: a guide for authors, editors, and publishers in the biological sciences, 5th ed. Council of Biology, Editors, Inc., Bethesda, Md |
| 27. |
Eady, E. A.,
J. I. Ross,
J. L. Tipper,
C. E. Walters,
J. H. Cove, and W. C. Noble.
1993.
Distribution of genes encoding erythromycin ribosomal methylases and an erythromycin efflux pump in epidemiologically distinct groups of staphylococci.
J. Antimicrob. Chemother.
31:211-217 |
| 28. | Epp, J. K., S. G. Burgett, and G. E. Schoner. 1987. Cloning and nucleotide sequence of a carbomycin-resistance gene from Streptomyces thermotolerans. Gene 53:73-83[Medline]. |
| 29. | Farrow, K. A., D. Lyras, and J. I. Rood. GenBank accession no. AF109075. |
| 30. | Fraimow, H., and C. Knob. 1997. Amplification of macrolide efflux pumps msr and mef from Enterococcus faecium by polymerase chain reaction, abstr. A-125, p. 22. In Abstracts of the 98th General Meeting of the American Society for Microbiology. American Society for Microbiology, Washington, D.C. |
| 31. |
Hächler, H.,
F. H. Kayser, and B. Berger-Bächi.
1987.
Homology of a transferable tetracycline resistance determinant of Clostridium difficile with Streptococcus (Enterococcus) faecalis transposon Tn916.
Antimicrob. Agents Chemother.
31:1033-1038 |
| 32. |
Halula, M.,
S. Manning, and F. L. Macrina.
1991.
Nucleotide sequence of ermFU, macrolide-lincosamide-streptogramin (MLS) resistance gene encoding an RNA methylase from the conjugal element of Bacteroides fragilis V503.
Nucleic Acids Res.
19:3453 |
| 33. | Hammerum, A. M., L. Jensen, L. Bogo, and F. M. Aarestrup. 1998. Detection of the satA gene and transferability of virginiamycin resistance in Enterococcus faecium from food-animals. FEMS Microbiol. Lett. 168:145-151[Medline]. |
| 34. | Hara, Q., and C. R. Hutchinson. 1990. Cloning of midecamycin (MLS)-resistance genes from Streptomyces mycarofaciens, Streptomyces lividans and Streptomyces coelicolor A3(2). J. Antibiot. (Tokyo) 43:977-991[Medline]. |
| 35. |
Hodgson, A. L. M.,
J. Krywult, and A. J. Radford.
1990.
Nucleotide sequence of the erythromycin resistance gene from Corynebacterium plasmid pNG2.
Nucleic Acids Res.
18:1891 |
| 36. | Hudson, C. R., M. C. Roberts, and F. C. Gherardini. 1998. Evidence of conjugal transfer of an erythromycin-resistance determinant in Borrelia burgdorferi, abstr. D-2, p. 223. In Abstracts of the 98th Annual Meeting of the American Society for Microbiology. American Society for Microbiology, Washington, D.C. |
| 37. | Inouye, M., T. Morohoshi, S. Horinouchi, and T. Beppu. 1994. Cloning and sequences of two macrolides-resistance-encoding genes from mycinamicin-producing Micromonospora griseorubida. Gene 141:39-46[Medline]. |
| 38. | Jenkins, G., M. Zalacain, and E. Cundliffe. 1989. Inducible ribosomal RNA methylation in Streptomyces lividans, conferring resistance to lincomycin. J. Gen. Microbiol. 129:2703-2714. |
| 39. |
Jensen, L. B.,
A. M. Hammerum,
F. M. Aarestrup,
A. E. van den Bogaard, and E. E. Stobberingh.
1998.
Occurrence of satA and vgb genes in streptogramin-resistant Enterococcus faecium isolates of animal and human origins in The Netherlands.
Antimicrob. Agents Chemother.
42:3330-3331 |
| 40. | Jensen, L. B., N. Frimodt-Moller, and F. M. Aarestrup. 1999. Presence of erm gene classes in Gram-positive bacteria of animal and human origin in Denmark. FEMS Microbiol. Lett. 170:151-158[Medline]. |
| 41. |
Johnston, N. J.,
J. C. de Azavedo,
J. D. Kellner, and D. E. Low.
1998.
Prevalence and characterization of the mechanisms of macrolide, lincosamide, and streptogramin resistance in isolates of Streptococcus pneumoniae.
Antimicrob. Agents Chemother.
42:2425-2426 |
| 42. | Kamimiya, S., and B. Weisblum. 1996. GenBank deposit: Streptomyces viridochromogenes rRNA (adenine-N6-) methyltransferase, ermSV gene. Accession no. U59450 |
| 43. |
Kataja, J.,
H. Seppälä,
M. Skurnik,
H. Sarkkinen, and P. Huovinen.
1998.
Different erythromycin resistance mechanisms in group C and group G streptococci.
Antimicrob. Agents Chemother.
42:1493-1494 |
| 44. |
Kataja, J.,
P. Huovinen,
M. Skurnik,
the Finnish Study Group for Antimicrobial Resistance, and H. Seppälä.
1999.
Erythromycin resistance genes in group A streptococci in Finland.
Antimicrob. Agents Chemother.
43:48-52 |
| 45. | Kim, S.-K., M.-C. Baek, S.-S. Choi, B.-K. Kim, and E.-C. Choi. 1996. Nucleotide sequence, expression and transcriptional analysis of the Escherichia coli mphK gene encoding macrolide-phosphotransferase K. Mol. Cells 6:153-160. |
| 46. |
Kovalic, D.,
R. B. Giannattasio,
H.-J. Jin, and B. Weisblum.
1994.
23S rRNA domain V, a fragment that can be specifically methylated in vitro by the ErmSF (TlrA) methyltransferase.
J. Bacteriol.
176:6992-6998 |
| 47. |
Leclercq, R., and P. Courvalin.
1991.
Bacterial resistance to macrolide, lincosamide, and streptogramin antibiotics by target modification.
Antimicrob. Agents Chemother.
35:1267-1272 |
| 48. |
Leclercq, R., and P. Courvalin.
1991.
Intrinsic and unusual resistance to macrolide, lincosamide, and streptogramin antibiotics in bacteria.
Antimicrob. Agents Chemother.
35:1273-1276 |
| 49. | Le Goffic, F., M. L. Capmau, M. L. Bonnet, C. Cerceau, C. J. Soussy, A. Dublanchet, and J. Duval. 1977. Plasmid-mediated pristinamycin resistance: PH1A, a pristinamycin 1A hydrolase. Ann. Inst. Pasteur 128:471-474. |
| 50. | Le Goffic, F., M. L. Capmau, M. L. Bonnet, C. Cerceau, C. J. Soussy, A. Dublanchet, and J. Duval. 1977. Plasmid-mediated pristinamycin resistance: PCIIA, a new enzyme which modifies pristinamycin IIA. J. Antibiot. 30:665-669[Medline]. |
| 51. |
Levy, S. B.,
L. M. McMurry,
V. Burdett,
P. Courvalin,
W. Hillen,
M. C. Roberts, and D. E. Taylor.
1989.
Nomenclature for tetracycline resistance determinants.
Antimicrob. Agents Chemother.
33:1373-1374 |
| 52. |
Levy, S. B.,
L. M. McMurry,
T. M. Barbosa,
V. Burdett,
P. Courvalin,
W. Hillen,
M. C. Roberts,
J. I. Rood, and D. E. Taylor.
1999.
Nomenclature for new tetracycline resistance determinants.
Antimicrob. Agents Chemother.
43:1523-1524 |
| 53. |
Luna, V. A.,
P. Coates,
E. A. Eady,
J. Cove,
T. T. H. Nguyen, and M. C. Roberts.
1999.
A variety of Gram-positive bacteria carry mobile mef genes.
J. Antimicrob. Chemother.
44:19-25 |
| 54. | Matsuoka, M., M. Inoue, and Y. Nakajima. 1995. A mechanism of resistance to partial macrolide and streptogramin B antibiotics in Staphylococcus aureus clinically isolated in Hungary. Biol. Pharm. Bull. 18:1482-1486[Medline]. |
| 55. | Matsuoka, M., M. Inoue, and Y. Nakajima. 1997. A dyadic plasmid that shows MLS and PMS resistance in Staphylococcus aureus. FEMS Microbiol. Lett. 148:91-96[Medline]. |
| 56. | Matsuoka, M., M. Inoue, and Y. Nakajima. 1998. A new class of erm genes mediating MLS-coresistance in Staphylococcus aureus: it resides on plasmid pMS97 together with msrSA' gene coding for an active efflux pump, abstr. C-35, p. 78. In Abstracts of the 38th Interscience Conference on Antimicrobial Agents and Chemotherapy. American Society for Microbiology, Washington, D.C. |
| 57. | Matsuoka, M., K. Endou, H. Kobayashi, M. Inoue, and Y. Nakajima. 1998. A plasmid that encodes three genes for resistance to macrolide antibiotics in Staphylococcus aureus. FEMS Microbiol. Lett. 167:221-227[Medline]. |
| 58. |
Meier, A.,
P. Kirschner,
B. Springer,
V. A. Steingrube,
B. A. Brown,
R. J. Wallace, Jr., and E. C. Böttger.
1994.
Identification of mutations in the 23S rRNA gene of clarithromycin-resistant Mycobacterium intracellulare.
Antimicrob. Agents Chemother.
38:381-384 |
| 59. |
Miller, E. S.,
C. R. Woese, and S. Brenner.
1991.
Description of the erythromycin-producing bacterium Arthrobacter sp. strain NRRL B-3381 as Aeromicrobium erythreum gen. nov., sp. nov.
Int. J. Syst. Bacteriol.
41:363-368 |
| 60. | Milton, I. D., C. L. Hewitt, and C. R. Harwood. 1992. Cloning and sequencing of a plasmid-mediated erythromycin resistance determinant from Staphylococcus xylosus. FEMS Microbiol. Lett. 76:141-147[Medline]. |
| 61. |
Monod, M.,
C. Denoya, and D. Dubnau.
1986.
Sequence and properties of pIM13, a macrolide-lincosamide-streptogramin B resistance plasmid from Bacillus subtilis.
J. Bacteriol.
167:138-147 |
| 62. |
Monod, M.,
S. Mohan, and D. Dubnau.
1987.
Cloning and analysis of ermG, a new macrolide-lincosamide-streptogramin B resistance element from Bacillus sphaericus.
J. Bacteriol.
169:340-350 |
| 63. | Noguchi, N., A. Emura, H. Matsuyama, K. O'Hara, M. Sasatsu, and M. Kono. 1995. Nucleotide sequence and characterization of erythromycin resistance determinant that encodes macrolide 2'-phosphotransferase I in Escherichia coli. Antimicrob. Agents Chemother. 39:2359-2363[Abstract]. |
| 64. | Noguchi, N., J. Katayama, and K. O'Hara. 1996. Cloning and nucleotide sequence of the mphB gene for macrolide 2'-phosphotransferase II in Escherichia coli. FEMS Microbiol. Lett. 144:197-202[Medline]. |
| 65. |
Oh, T.-G.,
A.-R. Kwon, and E.-C. Choi.
1998.
Induction of ermAMR from a clinical strain of Enterococcus faecalis by 16-membered-ring macrolide antibiotics.
J. Bacteriol.
180:5788-5791 |
| 66. |
O'Hara, K.,
T. Kanda,
K. Ohmiya,
T. Ebisu, and M. Kono.
1989.
Purification and characterization of macrolide 2'-phosphotransferase from a strain of Escherichia coli that is highly resistant to erythromycin.
Antimicrob. Agents Chemother.
33:1354-1357 |
| 66a. | O'Hara, K. Personal communication. |
| 67. | Ounissi, H., and P. Courvalin. 1985. Nucleotide sequence of the gene ereA encoding the erythromycin esterase in Escherichia coli. Gene 35:271-278[Medline]. |
| 68. |
Pang, Y.,
B. A. Brown,
V. A. Steingrube,
R. J. Wallace, Jr., and M. C. Roberts.
1994.
Tetracycline resistance determinants in Mycobacterium and Streptomyces species.
Antimicrob. Agents Chemother.
38:1408-1412 |
| 69. |
Pernodet, J. L.,
M. H. Blondelet-Rouault, and M. Guerineau.
1993.
Resistance to spiramycin in Streptomyces ambofaciens, the producer organism, involves at least two different mechanisms.
J. Gen. Microbiol.
139:1003-1011 |
| 70. | Peschke, U., H. Schmidt, H.-Z. Zhang, and W. Piepersberg. 1995. Molecular characterization of the lincomycin-production gene cluster of Streptomyces lincolnensis 78-11. Mol. Microbiol. 16:1137-1156[Medline]. |
| 71. |
Rasmussen, J. L.,
D. A. Odelson, and F. L. Macrina.
1986.
Complete nucleotide sequence and transcription of ermF, a macrolide-lincosamide-streptogramin B resistance determinant from Bacteroides fragilis.
J. Bacteriol.
168:523-533 |
| 72. |
Rende-Fournier, R.,
R. LeClercq,
M. Galimand,
J. Duval, and P. Courvalin.
1993.
Identification of the satA gene encoding a streptogramin A acetyltransferase in Enterococcus faecium BM4145.
Antimicrob. Agents Chemother.
37:2119-2125 |
| 73. | Richardson, M. A., S. Kuhstoss, P. Solenberg, N. A. Schaus, and R. N. Rao. 1987. A new shuttle cosmid vector, pKC505, for streptomycetes: its use in the cloning of three different spiramycin-resistance genes from a Streptomyces ambovaciens library. Gene 61:231-241[Medline]. |
| 74. | Roberts, A. N., G. S. Hudson, and S. Brenner. 1985. An erythromycin-resistance gene from an erythromycin-producing strain of Arthrobacter sp. Gene 35:259-270[Medline]. |
| 75. | Roberts, M. C. 1995. Distribution of tetracycline and macrolides-lincosamides-streptogramin B (MLS) genes in anaerobic bacteria. Clin. Infect. Dis. 20:S367-S369. |
| 76. | Roberts, M. C., and M. B. Brown. 1994. Macrolide-lincosamide resistance determinants in streptococcal species isolated from the bovine mammary gland. Vet. Microbiol. 40:253-261[Medline]. |
| 77. | Roberts, M. C., W. O. Chung, and D. E. Roe. 1996. Characterization of tetracycline and erythromycin determinants in Treponema denticola. Antimicrob. Agents Chemother. 40:1690-1694[Abstract]. |
| 78. |
Roberts, M. C.,
W. O. Chung,
D. Roe,
M. Xia,
C. Marquez,
G. Borthagaray,
W. L. Whittington, and K. K. Holmes.
1999.
Erythromycin-resistant Neisseria gonorrhoeae and oral commensal Neisseria spp. carry known rRNA methylase genes.
Antimicrob. Agents Chemother.
43:1367-1372 |
| 79. |
Roberts, M. C.,
L. V. McFarland,
P. Mullany, and M. E. Mulligan.
1994.
Characterization of the genetic basis of antibiotic resistance in Clostridium difficile.
J. Antimicrob. Chemother.
33:419-429 |
| 80. | Rodriguez, A. M., C. Olano, C. Vilches, C. Mendez, and J. A. Salas. 1993. Streptomyces antibioticus contains at least three olendomycin resistance determinants, one of which shows homology with proteins of the ABC-transporter superfamily. Mol. Microbiol. 8:571-582[Medline]. |
| 81. |
Roe, D. E.,
A. Weinberg, and M. C. Roberts.
1995.
Mobility of rRNA methylase genes in Campylobacter (Wolinella) rectus.
J. Antimicrob. Chemother.
36:738-740 |
| 82. |
Roe, D. E.,
A. Weinberg, and M. C. Roberts.
1996.
Mobile rRNA methylase genes in Actinobacillus actinomycetemcomitans.
J. Antimicrob. Chemother.
37:457-464 |
| 83. | Ross, J. I., E. A. Eady, J. H. Cove, and S. Baumberg. 1996. Minimal functional system required for expression of erythromycin resistance by msrA in Staphylococcus aureus RN4220. Gene 183:143-148[Medline]. |
| 84. | Ross, J. I., E. A. Eady, J. H. Cove, C. E. Jones, A. H. Ratyal, Y. W. Miller, S. Vyakrnam, and W. J. Cunliffe. 1989. Clinical resistance to erythromycin and clinidamycin in cutaneous propionibacteria isolated from acne patients is associated with mutations in 23S rRNA. Antimicrob. Agents Chemother. 41:1162-1165[Abstract]. |
| 85. | Rosteck, P. R., Jr., P. A. Reynolds, and C. L. Hershberger. 1991. Homology between proteins controlling Streptomyces fradiae tylosin resistance and ATP-binding transport. Gene 102:27-32[Medline]. |
| 86. |
Salyers, A. A.,
N. B. Shoemaker,
A. M. Stevens, and L.-Y. Li.
1995.
Conjugative transposons: an unusual and diverse set of integrated gene transfer elements.
Microbiol. Rev.
59:579-590 |
| 87. | Schoner, B., M. Geistlich, P. I. Rosteck, Jr., R. N. Rao, E. Seno, P. Reynolds, K. Cox, S. Burgett, and C. Hershberger. 1992. Sequence similarity between macrolide-resistance determinants and ATP-binding transport proteins. Gene 115:93-96[Medline]. |
| 88. |
Seppälä, H.,
M. Skurnik,
H. Soini,
M. C. Roberts, and P. Huovinen.
1998.
A novel erythromycin resistance methylase gene (ermTR) in Streptococcus pyogenes.
Antimicrob. Agents Chemother.
42:257-262 |
| 89. |
Shoemaker, N. B.,
R. D. Barber, and A. A. Salyers.
1989.
Cloning and characterization of a Bacteroides conjugal tetracycline-erythromycin resistance element by using a shuttle cosmid vector.
J. Bacteriol.
171:1294-1302 |
| 90. | Shortridge, V. D., R. K. Flamm, N. Ramer, J. Beyer, and S. K. Tanaka. 1996. Novel mechanism of macrolide resistance in Streptococcus pneumoniae. Diagn. Microbiol. Infect. Dis. 26:73-78[Medline]. |
| 91. |
Smith, C. J.
1987.
Nucleotide sequence analysis of Tn4551: use of ermFS operon fusions to detect promoter activity in Bacteroides fragilis.
J. Bacteriol.
169:4589-4596 |
| 92. | Sutcliffe, J., T. Grebe, A. Tait-Kamradt, and L. Wondrack. 1996. Detection of erythromycin-resistant determinants by PCR. Antimicrob. Agents Chemother. 40:2562-2566[Abstract]. |
| 93. | Sutcliffe, J., A. Tait-Kamradt, and L. Wondrack. 1996. Streptococcus pneumoniae and Streptococcus pyogenes resistant to macrolides but sensitive to clindamycin: a common resistance pattern mediated by an efflux system. Antimicrob. Agents Chemother. 40:1817-1824[Abstract]. |
| 94. | Tait-Kamradt, A., J. Clancy, M. Cronan, F. Dib-Hajj, L. Wondrack, W. Yuan, and J. Sutcliffe. 1997. mefE is necessary for the erythromycin-resistant M phenotype in Streptococcus pneumoniae. Antimicrob. Agents Chemother. 41:2251-2255[Abstract]. |
| 95. |
Trieu-Cuot, P.,
C. Poyart-Salmeron,
C. Carlier, and P. Courvalin.
1990.
Nucleotide sequence of the erythromycin resistance gene of the conjugative transposon Tn1545.
Nucleic Acids Res.
18:3660 |
| 96. | Vergis, E. N., and V. L. Yu. 1997. Macrolides are ideal for empiric therapy of community-acquired pneumonia in the immunocompetent host. Semin. Respir. Infect. 12:322-328[Medline]. |
| 97. |
Vergis, E. N., and V. L. Yu.
1998.
New macrolides or new quinolones as monotherapy for patients with community-acquired pneumonia; our cup runneth over?
Chest
113:1158-1159 |
| 98. | Wasteson, Y., D. E. Robe, K. Falk, and M. C. Roberts. 1996. Characterization of tetracycline and erythromycin resistance in Actinobacillus pleuropneumoniae. Vet. Microbiol. 48:41-50[Medline]. |
| 99. |
Weber, J. M.,
J. O. Leung,
G. T. Main,
R. H. B. Potenz,
T. J. Paulus, and J. P. DeWitt.
1990.
Organization of a cluster of erythromycin genes in Saccharopolyspora erythraea.
J. Bacteriol.
172:2372-2383 |
| 100. | Weisblum, B. 1999. Resistance to macrolide-lincosamide-streptogramin antibiotics, p. 682-698. In V. A. Fischetti (ed.), Gram-positive pathogens. American Society for Microbiology, Washington, D.C. |
| 101. | Weisblum, B. 1995. Erythromycin resistance by ribosome modification. Antimicrob. Agents Chemother. 39:577-585[Medline]. |
| 102. | Weisblum, B. 1995. Insights into erythromycin action from studies of its activity as inducer of resistance. Antimicrob. Agents Chemother. 39:797-805[Medline]. |
| 103. | Weisblum, B. 1998. Macrolide resistance. Drug Resist. Update 1:29-41. |
| 104. |
Werckenthin, C.,
S. Schwarz, and H. Westh.
1999.
Structural alterations in the translational attenuator of constitutively expressed ermC genes.
Antimicrob. Agents Chemother.
43:1681-1685 |
| 105. |
Werner, G., and W. Witte.
1999.
Characterization of a new enterococcal gene, satG, encoding a putative acetyltransferase conferring resistance to streptogramin A compounds.
Antimicrob. Agents Chemother.
43:1813-1814 |
| 106. | Widdowson, C. A., and K. P. Klugman. 1998. Emergence of the M phenotype of erythromycin-resistant pneumococci in South Africa. Emerg. Infect. Dis. 4:277-281[Medline]. |
| 107. | Young, H., A. Moyes, and A. McMillan. 1997. Azithromycin and erythromycin resistant Neisseria gonorrhoeae following treatment with azithromycin. Int. J. Sex. Transm. Dis. AIDS 8:299-302. |
| 108. |
Zalacain, M., and E. Cundliffe.
1989.
Methylation of 23S rRNA caused by tlrA (ermSF), a tylosin resistance determinant from Streptomyces fradiae.
J. Bacteriol.
171:4254-4260 |
| 109. | Zalacain, M., and E. Cundliffe. 1991. Cloning of tlrD, a fourth resistance gene, from the tylosin producer, Streptomyces fradiae. Gene 97:137-142[Medline]. |
| 110. | Zhang, H.-Z., H. Schmidt, and W. Piepersberg. 1992. Molecular cloning and characterization of two lincomycin-resistance genes, lmrA and lmrB, from Streptomyces lincolnensis 78-11. Mol. Microbiol. 6:2147-2157[Medline]. |
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