Characterization of the Mechanisms of Macrolide-Resistance among Streptococcus pneumoniae Isolates from Russia (original) (raw)
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Mechanisms of macrolide resistance among Streptococcus pneumoniae isolates from Russia
Antimicrobial Agents and Chemotherapy, 2008
Among 76 macrolide-nonsusceptible Streptococcus pneumoniae isolates collected between 2003 and 2005 from Central Russia, the resistance mechanisms detected in the isolates included erm(B) alone (50%), mef alone [mef(E), mef(I), or a different mef subclass; 19.7%], or both erm(B) and mef(E) (30.3%). Isolates with dual resistance genes [erm(B) and mef(E)] belonged to clonal complex CC81 or CC271.
Phenotypes and Genotypes of Macrolide-Resistant Streptococcus Pneumoniae
Balkan Medical Journal, 2015
Streptococcus pneumoniae (S. pneumoniae) is a major pathogen of bacterial pneumonia, meningitis, sinusitis and otitis media. Antimicrobial resistance in S. pneumoniae, including macrolide resistance, has been a growing problem in recent years due to the increasing numbers of cases with treatment failures of infections caused by macrolide-resistant pneumococci (1).
Antimicrobial Agents and Chemotherapy, 2000
Resistance to macrolides in pneumococci is generally mediated by methylation of 23S rRNA via erm (B) methylase which can confer a macrolide (M)-, lincosamide (L)-, and streptogramin B (S B )-resistant (MLS B ) phenotype or by drug efflux via mef (A) which confers resistance to 14- and 15-membered macrolides only. We studied 20 strains with unusual ML or MS B phenotypes which did not harbor erm (B) or mef (A). The strains had been isolated from patients in Eastern Europe and North America from 1992 to 1998. These isolates were found to contain mutations in genes for either 23S rRNA or ribosomal proteins. Three strains from the United States with an ML phenotype, each representing a different clone, were characterized as having an A2059G ( Escherichia coli numbering) change in three of the four 23S rRNA alleles. Susceptibility to macrolides and lincosamides decreased as the number of alleles in isogenic strains containing A2059G increased. Sixteen MS B strains from Eastern Europe were...
Antimicrobial Agents and Chemotherapy, 2010
Streptococcus pneumoniae has emerged as an important clinical problem worldwide over the past decade. The aim of this study was to analyze the phenotypes (serotype and antibiotic susceptibility), genotypes (multilocus sequence type [MLST] and antibiotic resistance gene/transposon profiles) among the 31% (102/328) of invasive isolates from children in New South Wales, Australia, in 2005 that were resistant to erythromycin. Three serotypes-19F (47 isolates [46%]), 14 (27 isolates [26%]), and 6B (12 isolates [12%])-accounted for 86 (84%) of these 102 isolates. Seventy four (73%) isolates had the macrolide-lincosamide-streptogramin B (MLS B ) resistance phenotype and carried Tn916 transposons (most commonly Tn6002); of these, 73 (99%) contained the erythromycin ribosomal methylase gene [erm(B)], 34 (47%) also carried the macrolide efflux gene [mef(E)], and 41 (55%) belonged to serotype 19F. Of 28 (27%) isolates with the M phenotype, 22 (79%) carried mef(A), including 16 (57%) belonging to serotype 14, and only six (19%) carried Tn916 transposons. Most (84%) isolates which contained mef also contained one of the msr(A) homologues, mel or msr(D); 38 of 40 (95%) isolates with mef(E) (on mega) carried mel, and of 28 (39%) isolates with mef(A), 10 (39%) carried mel and another 11(39%) carried msr(D), on Tn1207.1. Two predominant macrolide-resistant S. pneumoniae clonal clusters (CCs) were identified in this population. CC-271 contained 44% of isolates, most of which belonged to serotype 19F, had the MLS B phenotype, were multidrug resistant, and carried transposons of the Tn916 family; CC-15 contained 23% of isolates, most of which were serotype 14, had the M phenotype, and carried mef(A) on Tn1207.1. Erythromycin resistance among S. pneumoniae isolates in New South Wales is mainly due to the dissemination of multidrug-resistant S. pneumoniae strains or horizontal spread of the Tn916 family of transposons.
Macrolide Resistance in Streptococcus pneumoniae in Hong Kong
Antimicrobial Agents and Chemotherapy, 2001
Erythromycin resistance rates among penicillin-susceptible Streptococcus pneumoniae were 38 and 92% among penicillin-intermediate and -resistant S. pneumoniae isolates from Hong Kong, respectively, and 27% (43 of 158) of the isolates showed the MLS B phenotype, and the majority carried the ermB gene; 73% (115 of 158) displayed the M phenotype, and all possessed the mef gene. The MLS B phenotype was predominant in penicillin-susceptible, macrolide-resistant isolates and in penicillin-nonsusceptible isolates of serotype 6B, whilst the M phenotype was predominant in penicillin-intermediate or -resistant isolates belonging to serotype 23F or 19F. Extensive spread of clones of drug-resistant pneumococci has led to the widespread presence of macrolide resistance in S. pneumoniae in Hong Kong.
Macrolide Resistance Among Invasive Streptococcus pneumoniae Isolates
JAMA, 2001
ACROLIDES ARE RECOMmended as first-line therapy for adults in the United States and Canada with community-acquired pneumonia. 1-3 Newer macrolides (eg, azithromycin, clarithromycin) are popular because of convenient dosing schedules and fewer adverse effects. Unfortunately, resistance to macrolides among Streptococcus pneumoniae, the most common cause of communityacquired pneumonia, 4 has been increasing in the United States. 5-8 Pneumococcal macrolide resistance is usually expressed as 1 of 2 phenotypes. The first, known as M phenotype, is an efflux pump associated with the mefE gene that results in efflux of macrolides from the cell. 9 These organisms exhibit resistance to 14-and 15member macrolide antibiotics, including erythromycin, clarithromycin, and azithromycin. M phenotype isolates typically have moderate levels of macrolide resistance (ie, minimum inhibi-tory concentrations [MICs] in the range of 1-32 µg/mL) and are almost always susceptible to clindamycin. 10 A second phenotype, MLS B , results from
Archives of Biological Sciences, 2014
Macrolide resistance in Streptococcus pneumoniae and in group A streptococci (GAS) is a significant problem worldwide. In Serbia, data on the mechanisms of resistance and the corresponding resistance genes in streptococci are largely lacking. Therefore, we analyzed the distribution of macrolide resistance phenotypes and genotypes in 44 macrolideresistant GAS (MRGAS) and 50 macrolide-resistant S. pneumoniae (MRSP) isolates collected in the same period. The double disk diffusion test and PCR were used to analyze resistance phenotypes and resistance genes, respectively. Among MRSP, the MLSB phenotype dominated, whereas the M phenotype was the most prevalent among MRGAS isolates. Consequently, in MRSP, the ermB gene was the most common (n=40, 80%), followed by the mefA gene (n=7,14%). In MRGAS strains, mefA dominated (n=27, 61%), followed by ermA (n=15, 33%) and ermB (n=3, 7%). In 3 MRSP isolates no resistance genes were detected, while one MRGAS strain with iMLSB phenotype harbored both ermA and mefA genes.
Macrolide-resistant phenotypes of invasive streptococcus pneumoniae isolates in Serbia
Archives of Biological Sciences, 2012
Macrolide resistance in Streptococcus pneumoniae has emerged as an important worldwide problem over the past decade. The aim of this study was to investigate macrolide-resistant phenotypes and the antimicrobial susceptibility patterns of invasive pneumococci in Serbia. A total of 68 invasive pneumococcal strains, collected from 2009 to 2011, were sent from regional laboratories to the national reference Laboratory. Susceptibility testing was performed using the vItek2 system and phenotypes were determined by triple-test. Overall penicillin and erythromycin nonsusceptibility rates were 26% and 43%, respectively. resistance rates were higher in children than in adults. Co-resistance to penicillin and erythromycin was detected in 18% strains. resistance rates to the third generation of cephalosporins, tMp-SXt and tetracycline were 16%, 37% and 29%, respectively. All isolates were fully susceptible to vancomycin, linezolid, fluoroquinolones, telithromycin and rifampicin. twenty-two isolates (79%) an expressed macrolide-lincosamide-streptogramin B (MLS B) resistance phenotype and M phenotype was found in 21% of macrolide resistant strains.