scholarly journals Phenotypes and Genotypes of Erythromycin-ResistantStreptococcus pyogenes Strains in Italy and Heterogeneity of Inducibly Resistant Strains

1999 ◽  
Vol 43 (8) ◽  
pp. 1935-1940 ◽  
Author(s):  
Eleonora Giovanetti ◽  
Maria Pia Montanari ◽  
Marina Mingoia ◽  
Pietro Emanuele Varaldo
Keyword(s):  
Streptococcus Pyogenes ◽  
Tetracycline Resistance ◽  
Erythromycin Resistance ◽  
Testing Conditions ◽  
Resistant Strains ◽  
Methylase Gene ◽  
Set Up ◽  
Susceptibility Patterns ◽  
Disk Test ◽  
Level Resistance

ABSTRACT A total of 387 clinical strains of erythromycin-resistant (MIC, ≥1 μg/ml) Streptococcus pyogenes, all isolated in Italian laboratories from 1995 to 1998, were examined. By the erythromycin-clindamycin double-disk test, 203 (52.5%) strains were assigned to the recently described M phenotype, 120 (31.0%) were assigned to the inducible macrolide, lincosamide, and streptogramin B resistance (iMLS) phenotype, and 64 (16.5%) were assigned to the constitutive MLS resistance (cMLS) phenotype. The inducible character of the resistance of the iMLS strains was confirmed by comparing the clindamycin MICs determined under normal testing conditions and those determined after induction by pregrowth in 0.05 μg of erythromycin per ml. The MICs of erythromycin, clarithromycin, azithromycin, josamycin, spiramycin, and the ketolide HMR3004 were then determined and compared. Homogeneous susceptibility patterns were observed for the isolates of the cMLS phenotype (for all but one of the strains, HMR3004 MICs were 0.5 to 8 μg/ml and the MICs of the other drugs were >128 μg/ml) and those of the M phenotype (resistance only to the 14- and 15-membered macrolides was recorded, with MICs of 2 to 32 μg/ml). Conversely, heterogeneous susceptibility patterns were observed in the isolates of the iMLS phenotype, which were subdivided into three distinct subtypes designated iMLS-A, iMLS-B, and iMLS-C. The iMLS-A strains (n = 84) were highly resistant to the 14-, 15-, and 16-membered macrolides and demonstrated reduced susceptibility to low-level resistance to HMR3004. The iMLS-B strains (n = 12) were highly resistant to the 14- and 15-membered macrolides, susceptible to the 16-membered macrolides (but highly resistant to josamycin after induction), and susceptible to HMR3004 (but intermediate or resistant after induction). The iMLS-C strains (n = 24) had lower levels of resistance to the 14- and 15-membered macrolides (with erythromycin MICs increasing two to four times after induction), were susceptible to the 16-membered macrolides (but resistant to josamycin after induction), and remained susceptible to HMR3004, also after induction. The erythromycin resistance genes in 100 isolates of the different groups were investigated by PCR. All cMLS and iMLS-A isolates tested had theermAM (ermB) gene, whereas all iMLS-B and iMLS-C isolates had the ermTR gene (neither methylase gene was found in isolates of other groups). The M isolates had only the macrolide efflux (mefA) gene, which was also found in variable proportions of cMLS, iMLS-A, iMLS-B, and iMLS-C isolates. The three iMLS subtypes were easily differentiated by a triple-disk test set up by adding a josamycin disk to the erythromycin and clindamycin disks of the conventional double-disk test. Tetracycline resistance was not detected in any isolate of the iMLS-A subtype, whereas it was observed in over 90% of both iMLS-B and iMLS-C isolates.

scholarly journals Prevalence and Mechanisms of Macrolide Resistance in Invasive and Noninvasive Group B Streptococcus Isolates from Ontario, Canada

2001 ◽  
Vol 45 (12) ◽  
pp. 3504-3508 ◽  
Author(s):  
Joyce C. S. de Azavedo ◽  
Mary McGavin ◽  
Carla Duncan ◽  
Donald E. Low ◽  
Allison McGeer
Keyword(s):  
Group B Streptococcus ◽  
Tetracycline Resistance ◽  
Macrolide Resistance ◽  
Limited Information ◽  
Erythromycin Resistance ◽  
Vaginal Swabs ◽  
Resistant Strains ◽  
Neonatal Blood ◽  
Methylase Gene ◽  
Group B

ABSTRACT Macrolide resistance has been demonstrated in group B streptococcus (GBS), but there is limited information regarding mechanisms of resistance and their prevalence. We determined these in GBS obtained from neonatal blood cultures and vaginal swabs from pregnant women. Of 178 isolates from cases of neonatal GBS sepsis collected from 1995 to 1998, 8 and 4.5% were resistant to erythromycin and clindamycin, respectively, and one isolate showed intermediate penicillin resistance (MIC, 0.25 μg/ml). Of 101 consecutive vaginal or rectal/vaginal isolates collected in 1999, 18 and 8% were resistant to erythromycin and clindamycin, respectively. Tetracycline resistance was high (>80%) among both groups of isolates. Of 32 erythromycin-resistant isolates, 28 possessed the ermmethylase gene (7 ermB and 21 ermTR/ermA) and 4 harbored the mefA gene; one isolate harbored both genes. One isolate which was susceptible to erythromycin but resistant to clindamycin (MIC, 4 μg/ml) was found to have thelinB gene, previously identified only inEnterococcus faecium. The mreA gene was found in all the erythromycin-resistant strains as well as in 10 erythromycin-susceptible strains. The rate of erythromycin resistance increased from 5% in 1995–96 to 13% in 1998–99, which coincided with an increase in macrolide usage during that time.

scholarly journals Genetic Elements Carrying erm(B) in Streptococcus pyogenes and Association with tet(M) Tetracycline Resistance Gene

2007 ◽  
Vol 51 (4) ◽  
pp. 1209-1216 ◽  
Author(s):  
Andrea Brenciani ◽  
Alessandro Bacciaglia ◽  
Manuela Vecchi ◽  
Luca A. Vitali ◽  
Pietro E. Varaldo ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Tetracycline Resistance ◽  
Complete Sequence ◽  
M Gene ◽  
Genetic Elements ◽  
Conjugative Transposons ◽  
Dna Insertion ◽  
Methylase Gene ◽  
Genotypic Characteristics ◽  
M Sequences

ABSTRACT This study was directed at characterizing the genetic elements carrying the methylase gene erm(B), encoding ribosome modification-mediated resistance to macrolide, lincosamide, and streptogramin B (MLS) antibiotics, in Streptococcus pyogenes. In this species, erm(B) is responsible for MLS resistance in constitutively resistant isolates (cMLS phenotype) and in a subset (iMLS-A) of inducibly resistant isolates. A total of 125 erm(B)-positive strains were investigated, 81 iMLS-A (uniformly tetracycline susceptible) and 44 cMLS (29 tetracycline resistant and 15 tetracycline susceptible). Whereas all tetracycline-resistant isolates carried the tet(M) gene, tet(M) sequences were also detected in most tetracycline-susceptible isolates (81/81 iMLS-A and 7/15 cMLS). In 2 of the 8 tet(M)-negative cMLS isolates, erm(B) was carried by a plasmid-located Tn917-like transposon. erm(B)- and tet(M)-positive isolates were tested by PCR for the presence of genes int (integrase), xis (excisase), and tndX (resolvase), associated with conjugative transposons of the Tn916 family. In mating experiments using representatives of different combinations of phenotypic and genotypic characteristics as donors, erm(B) and tet(M) were consistently cotransferred, suggesting their linkage in individual genetic elements. The linkage was confirmed by pulsed-field gel electrophoresis and hybridization studies, and different elements, variably associated with the different phenotypes/genotypes, were detected and characterized by amplification and sequencing experiments. A previously unreported genetic organization, observed in all iMLS-A and some cMLS isolates, featured an erm(B)-containing DNA insertion into the tet(M) gene of a defective Tn5397, a Tn916-related transposon. This new element was designated Tn1116. Genetic elements not previously described in S. pyogenes also included Tn6002, an unpublished transposon whose complete sequence is available in GenBank, and Tn3872, a composite element resulting from the insertion of the Tn917 transposon into Tn916 [associated with a tet(M) gene expressed in some cMLS isolates and silent in others]. The high frequency of association between a tetracycline-susceptible phenotype and tet(M) genes suggests that transposons of the Tn916 family, so far typically associated solely with a tetracycline-resistant phenotype, may be more widespread in S. pyogenes than currently believed.

scholarly journals Presence of the tet(O) Gene in Erythromycin- and Tetracycline-Resistant Strains of Streptococcus pyogenes and Linkage with either the mef(A) or the erm(A) Gene

2003 ◽  
Vol 47 (9) ◽  
pp. 2844-2849 ◽  
Author(s):  
Eleonora Giovanetti ◽  
Andrea Brenciani ◽  
Remo Lupidi ◽  
Marilyn C. Roberts ◽  
Pietro E. Varaldo
Keyword(s):  
Streptococcus Pyogenes ◽  
Resistance Genes ◽  
Gel Electrophoresis ◽  
Tetracycline Resistance ◽  
Pulsed Field Gel Electrophoresis ◽  
M Gene ◽  
Pulsed Field ◽  
Conjugative Transposons ◽  
Tetracycline Resistance Genes ◽  
Resistant Strains

ABSTRACT Sixty-three recent Italian clinical isolates of Streptococcus pyogenes resistant to both erythromycin (MICs ≥ 1 μg/ml) and tetracycline (MICs ≥ 8 μg/ml) were genotyped for macrolide and tetracycline resistance genes. We found 19 isolates carrying the mef(A) and the tet(O) genes; 25 isolates carrying the erm(A) and tet(O) genes; and 2 isolates carrying the erm(A), tet(M), and tet(O) genes. The resistance of all erm(A)-containing isolates was inducible, but the isolates could be divided into two groups on the basis of erythromycin MICs of either >128 or 1 to 4 μg/ml. The remaining 17 isolates included 15 isolates carrying the erm(B) gene and 2 isolates carrying both the erm(B) and the mef(A) genes, with all 17 carrying the tet(M) gene. Of these, 12 carried Tn916-Tn1545-like conjugative transposons. Conjugal transfer experiments demonstrated that the tet(O) gene moved with and without the erm(A) gene and with the mef(A) gene. These studies, together with the results of pulsed-field gel electrophoresis experiments and hybridization assays with DNA probes specific for the tet(O), erm(A), and mef(A) genes, suggested a linkage of tet(O) with either erm(A) or mef(A) in erythromycin- and tetracycline-resistant S. pyogenes isolates. By amplification and sequencing experiments, we detected the tet(O) gene ca. 5.5 kb upstream from the mef(A) gene. This is the first report demonstrating the presence of the tet(O) gene in S. pyogenes and showing that it may be linked with another gene and can be moved by conjugation from one chromosome to another.

scholarly journals Prevalence and association of PCR ribotypes of Clostridium difficile isolated from symptomatic patients from Warsaw with macrolide-lincosamide-streptogramin B (MLSB) type resistance

2006 ◽  
Vol 55 (2) ◽  
pp. 207-213 ◽  
Author(s):  
Hanna Pituch ◽  
Jon S. Brazier ◽  
Piotr Obuch-Woszczatyński ◽  
Dorota Wultańska ◽  
Felicja Meisel-Mikołajczyk ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
University Hospital ◽  
Erythromycin Resistance ◽  
Toxin B ◽  
Pcr Ribotyping ◽  
Methylase Gene ◽  
High Level ◽  
The University ◽  
Antibiotic Associated Diarrhoea ◽  
Level Resistance

Isolates (79 in total) of Clostridium difficile obtained over a 2 year period from 785 patients suspected of having C. difficile-associated diarrhoea (CDAD) and being hospitalized in the University Hospital in Warsaw were characterized by toxigenicity profile and PCR ribotyping. Furthermore, their susceptibility to clindamycin and erythromycin was determined. Among the 79 C. difficile isolates, 35 were classified as A+B+, 1 as A+B+CDT+, 36 as A−B+ and 7 as A−B−. A total of 21 different PCR ribotypes was detected. Two main A+B+ strains circulated in our hospital: ribotype 014 and ribotype 046. Unexpectedly, the predominant PCR ribotype was type 017, a known A−B+ strain, and this accounted for about 45·5 % of all isolates cultured from patients with CDAD. Isolates belonging to PCR ribotype 017 were found in cases from epidemics of antibiotic-associated diarrhoea in the internal and surgery units. High-level resistance (MIC⩾256 mg l−1) to clindamycin and erythromycin was found in 39 (49 %) of the C. difficile isolates. Interestingly, 34 (94 %) of macrolide-lincosamide-streptogramin B (MLSB) type resistance strains did not produce toxin A, but produced toxin B and were A−B+ ribotype 017. Thirty-seven of the high-level resistance strains harboured the erythromycin-resistance methylase gene (ermB). C. difficile isolates (2/29) that had high-level clindamycin and erythromycin resistance, and belonged to PCR ribotype 046, were ermB negative. These investigations revealed that the predominant C. difficile strain isolated from symptomatic patients hospitalized in University Hospital in Warsaw was MLSB-positive clindamycin/erythromycin-resistant PCR ribotype 017.

scholarly journals A Novel Erythromycin Resistance Methylase Gene (ermTR) in Streptococcus pyogenes

1998 ◽  
Vol 42 (2) ◽  
pp. 257-262 ◽  
Author(s):  
Helena Seppälä ◽  
Mikael Skurnik ◽  
Hanna Soini ◽  
Marilyn C. Roberts ◽  
Pentti Huovinen
Keyword(s):  
Staphylococcus Aureus ◽  
Nucleotide Sequence ◽  
Streptococcus Pyogenes ◽  
Resistance Genes ◽  
Target Site ◽  
Clinical Strain ◽  
Erythromycin Resistance ◽  
Coagulase Negative Staphylococci ◽  
Methylase Gene

ABSTRACT Erythromycin resistance among streptococci is commonly due to target site modification by an rRNA-methylating enzyme, which results in coresistance to macrolide, lincosamide, and streptogramin B antibiotics (MLSB resistance). Genes belonging to theermAM (ermB) gene class are the only erythromycin resistance methylase (erm) genes inStreptococcus pyogenes with MLSB resistance that have been sequenced so far. We identified a novelerm gene, designated ermTR, from an erythromycin-resistant clinical strain of S. pyogenes(strain A200) with an inducible type of MLSBresistance. The nucleotide sequence of ermTR is 82.5% identical to ermA, previously found, for example, in Staphylococcus aureus and coagulase-negative staphylococci. Our finding provides the first sequence of anerm gene other than ermAM that mediates MLSB resistance in S. pyogenes.

scholarly journals Antimicrobial susceptibility patterns and genomic diversity in strains of Streptococcus pyogenes isolated in 1978–1997 in different Brazilian cities

2003 ◽  
Vol 52 (3) ◽  
pp. 251-258 ◽  
Author(s):  
Maria Celeste Nunes De Melo ◽  
Agnes Marie Sá Figueiredo ◽  
Bernadete Teixeira Ferreira-Carvalho
Keyword(s):  
Genetic Diversity ◽  
Streptococcus Pyogenes ◽  
Antimicrobial Susceptibility ◽  
Genomic Dna ◽  
Tetracycline Resistance ◽  
Genomic Diversity ◽  
The Other ◽  
Geographical Locations ◽  
Susceptibility Patterns ◽  
Healthy Carriers

Penicillin has been the antimicrobial of choice for the treatment of Streptococcus pyogenes infections for almost six decades. Although penicillin-resistant isolates have not been described to date, clinical failures have been reported after treatment with β-lactams. In this study, we analysed the antimicrobial susceptibility and genetic diversity of S. pyogenes isolates obtained from healthy carriers or patients in different cities in the south and south east of Brazil. The MICs were determined for penicillin and seven other antimicrobials. Penicillin tolerance was also investigated. Genetic diversity was analysed by PFGE after SmaI fragmentation of the genomic DNA. All 211 isolates tested were susceptible to penicillin (MIC 0.0025–0.02 mg l−1). Four isolates were moderately penicillin-tolerant (MBC/MIC = 16 mg l−1). Most of the other drugs tested were very active against the strains examined, except for tetracycline, to which 50 % of strains were resistant. We also found extensive genetic diversity, in that 60 different patterns were recognized in the 96 strains studied. Indeed, we found no correlation between tetracycline resistance and clonality. Despite this diversity, some PFGE patterns persisted for up to 18 years and specific clone types were spread over different geographical locations

scholarly journals Molecular epidemiology of macrolide resistant Group A streptococci from Puducherry, India

2017 ◽  
Vol 11 (09) ◽  
pp. 679-683 ◽  
Author(s):  
Tintu Abraham ◽  
Sujatha Sistla
Keyword(s):  
Streptococcus Pyogenes ◽  
Macrolide Resistance ◽  
Streptococcal Infections ◽  
Genetic Determinants ◽  
Erythromycin Resistance ◽  
Group A ◽  
Macrolide Resistance Gene ◽  
Resistant Group ◽  
Resistant Strains ◽  
Resistance Rates

Introduction: In penicillin allergic patients, macrolides are the most commonly used antibiotics for treating streptococcal infections, irrespective of the higher resistance rates. The objective of this study was to evaluate the comparative prevalence, phenotypes, and genetic determinants of macrolide resistance and associated emm types among different clinical isolates of Streptococcus pyogenes. Methodology: A total of 173 Streptococcus pyogenes isolates were examined for macrolide resistance phenotype by double-disc test, resistance determinants by multiplex PCR and emm genotyping. Results: Erythromycin resistance was found in 51.4% of isolates, with MIC90 ≥ 256 µg/mL Inducible phenotype was commonly found (iMLS, 67.4%) followed by the M phenotype (32.5%). Among these isolates, 65.1% harboured ermB and 32.5% mefA as sole macrolide resistance gene, whereas presence of both, ermB plus mefA was observed in 2.2% cases. The most common types among resistant strains were emm63 (11.2%), emm44 (6.7%), emm42 (5.6%), and emm75.3, emm82, emm85, emm92, emm111.1 (4.4% each). Statistically significant association was observed between emm63, emm44 and erythromycin resistance (p ≤ 0.05). Association of these emm types and macrolide resistance have not been reported earlier. Conclusion: Higher macrolide resistance in this study can be attributed to overuse and misuse of this antibiotic. These findings indicate that macrolides should not be empirically used for treating severe streptococcal infections.

scholarly journals Resistance to Erythromycin and Telithromycin in Streptococcus pyogenes Isolates Obtained between 1999 and 2002 from Greek Children with Tonsillopharyngitis: Phenotypic and Genotypic Analysis

2006 ◽  
Vol 50 (1) ◽  
pp. 256-261 ◽  
Author(s):  
Ioanna N. Grivea ◽  
Adnan Al-Lahham ◽  
George D. Katopodis ◽  
George A. Syrogiannopoulos ◽  
Ralf René Reinert
Keyword(s):  
Streptococcus Pyogenes ◽  
Gene Sequence ◽  
Sequence Type ◽  
23S Rrna ◽  
Erythromycin Resistance ◽  
Genotypic Analysis ◽  
High Incidence ◽  
Resistant Strains ◽  
Clonal Spread ◽  
Western Greece

ABSTRACT Since the late 1990s, the prevalence of erythromycin-resistant Streptococcus pyogenes has significantly increased in several European countries. Between January 1999 and December 2002, 1,577 isolates of S. pyogenes were recovered from children with tonsillopharyngitis living in various areas of Western Greece. Erythromycin resistance was observed in 379 (24%) of the 1,577 isolates. All erythromycin-resistant strains along with 153 randomly selected erythromycin-susceptible S. pyogenes isolates were tested for their antimicrobial susceptibility, resistance phenotypes, and genotypes. Representative isolates underwent emm gene sequence typing. Isolates with reduced susceptibility to telithromycin (MIC, ≥2 μg/ml) were studied for multilocus sequence type, L22, L4, and 23S rRNA mutations. Of the total 379 erythromycin-resistant isolates, 193 (50.9%) harbored the mef(A) gene, 163 (43%) erm(A), 1 (0.3%) mef(A) plus erm(A), and 22 (5.8%) the erm(B) gene. Among the erythromycin-susceptible isolates, emm 1 (25%), emm 2 (12.5%), and emm 77 (12.5%) predominated. Furthermore, among the erythromycin-resistant isolates, emm 4 (30.6%), emm 28 (22.2%), and emm 77 (12.5%) prevailed. Resistance to telithromycin was observed in 22 (5.8%) of the erythromycin-resistant isolates. Sixteen (72.7%) of the 22 isolates appeared to be clonally related, since all of them belonged to emm type 28 and multilocus sequence type 52. One of the well-known mutations (T2166C) in 23S rRNA, as well as a new one (T2136C), was detected in erythromycin- and telithromycin-resistant isolates. High incidence of macrolide resistance and clonal spread of telithromycin resistance were the characteristics of the Greek S. pyogenes isolates obtained from 1999 to 2002.

scholarly journals Identification of an erm(A) Erythromycin Resistance Methylase Gene in Streptococcus pneumoniaeIsolated in Greece

2001 ◽  
Vol 45 (1) ◽  
pp. 342-344 ◽  
Author(s):  
George A. Syrogiannopoulos ◽  
Ioanna N. Grivea ◽  
Amelia Tait-Kamradt ◽  
George D. Katopodis ◽  
Nicholas G. Beratis ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Streptococcus Pyogenes ◽  
Erythromycin Resistance ◽  
Methylase Gene

ABSTRACT In a serotype 11A clone of erythromycin-resistant pneumococci isolated from young Greek carriers, we identified the nucleotide sequence of erm(A), a methylase gene previously described as erm(TR) in Streptococcus pyogenes. Theerm(A) pneumococci were resistant to 14- and 15-member macrolides, inducibly resistant to clindamycin, and susceptible to streptogramin B. To our knowledge, this is the first identification of resistance to erythromycin in S. pneumoniae attributed solely to the carriage of the erm(A) gene.

scholarly journals Two Distinct Genetic Elements Are Responsible forerm(TR)-Mediated Erythromycin Resistance in Tetracycline-Susceptible and Tetracycline-Resistant Strains of Streptococcus pyogenes

2011 ◽  
Vol 55 (5) ◽  
pp. 2106-2112 ◽  
Author(s):  
Andrea Brenciani ◽  
Erika Tiberi ◽  
Alessandro Bacciaglia ◽  
Dezemona Petrelli ◽  
Pietro E. Varaldo ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Integration Site ◽  
Hot Spot ◽  
The Other ◽  
23S Rrna ◽  
Erythromycin Resistance ◽  
High Identity ◽  
Content Type ◽  
Genetic Elements ◽  
Resistant Strains

ABSTRACTInStreptococcus pyogenes, inducible erythromycin (ERY) resistance is due to posttranscriptional methylation of an adenine residue in 23S rRNA that can be encoded either by theerm(B) gene or by the more recently describederm(TR) gene. Twoerm(TR)-carrying genetic elements, showing extensive DNA identities, have thus far been sequenced: ICE10750-RD.2 (∼49 kb) and Tn1806(∼54 kb), from tetracycline (TET)-susceptible strains ofS. pyogenesandStreptococcus pneumoniae, respectively. However, TET resistance, commonly mediated by thetet(O) gene, is widespread inerm(TR)-positiveS. pyogenes. In this study, 23S. pyogenesclinical strains witherm(TR)-mediated ERY resistance—3 TET susceptible and 20 TET resistant—were investigated. Twoerm(TR)-carrying elements sharing only a short, high-identityerm(TR)-containing core sequence were comprehensively characterized: ICESp1108 (45,456 bp) from the TET-susceptible strain C1 and ICESp2905 (65,575 bp) from the TET-resistant strain iB21. While ICESp1108 exhibited extensive identities to ICE10750-RD.2 and Tn1806, ICESp2905 showed a previously unreported genetic organization resulting from the insertion of separateerm(TR)- andtet(O)-containing fragments in a scaffold of clostridial origin. Transferability by conjugation of theerm(TR) elements from the same strains used in this study had been demonstrated in earlier investigations. Unlike ICE10750-RD.2 and Tn1806, which are integrated into anhsdMchromosomal gene, both ICESp1108 and ICESp2905 shared the chromosomal integration site at the 3′ end of the conservedrumgene, which is an integration hot spot for several mobile streptococcal elements. By using PCR-mapping assays,erm(TR)-carrying elements closely resembling ICESp1108 and ICESp2905 were shown in the other TET-susceptible and TET-resistant test strains, respectively.

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