Increased Prevalence of Erythromycin Resistance in Streptococci: Substantial Upsurge in Erythromycin-Resistant M Phenotype inStreptococcus pyogenes(1979-1998) but Not inStreptococcus pneumoniae(1985-1999) in Taiwan

Abstract

A total of 394 nonduplicate isolates of Streptococcus pyogenes collected from 1979 to 1998 and 267 nonduplicate isolates of Streptococcus pneumoniae collected from October, 1998, to May, 1999, in Taiwan were evaluated. Among the 220 erythromycin-resistant (MIC, > or =1 microg/ml) S. pyogenes isolates, 35% had an M phenotype and 65% had an ML phenotype (inducible resistance [iML], 0.5%, and constitutive resistance [cML], 64.5%). Among the 243 erythromycin-resistant S. pneumoniae isolates, the majority (65.4%) had an ML phenotype (iML, 0.4%, and cML, 65%) and 34.6% had an M phenotype. A substantial upsurge in the incidence of M-phenotype erythromycin-resistant isolates was found with time for S. pyogenes (0% in 1979-1984 and 100% in 1997-1998), and an increasing incidence of M-phenotype among erythromycin-resistant S. pneumoniae was also noted (<20% before 1994 and 45.4% in 1999). All S. pyogenes and all but four S. pneumoniae isolates exhibiting a cML or iML phenotype had harbored the ermAM gene. The presence of the mefA gene was demonstrated in all isolates of S. pyogenes and the mefE gene in all but four S. pneumoniae isolates exhibiting the M phenotype. Due to the increasing susceptibility of S. pyogenes and S. pneumoniae isolates to clindamycin, susceptibility tests of these two organisms to macrolides and clindamycin should be performed simultaneously in the clinical microbiology laboratory, particularly in areas with high rates of macrolide resistance.

In Vitro Susceptibilities of Shigella flexneri and Streptococcus pyogenes to Inner Gel of Aloe barbadensis Miller

“…There is also increasing evidence that antibiotic therapy can exacerbate the symptoms of gastrointestinal diseases (6,9), and an alternative treatment would be beneficial. In addition, susceptibility of the gram-positive Streptococcus pyogenes to AV was briefly investigated, as this is another organism which is beginning to show antibiotic resistance (7,8). Shigella flexneri (NCTC 9950) and Streptococcus pyogenes Gp A (ATCC 19615) were purchased from the Public Health Laboratory Services (Porton Down, Salisbury, United Kingdom).…”

M.SpyI, a DNA Methyltransferase Encoded on a mefA Chimeric Element, Modifies the Genome of Streptococcus pyogenes

“…Methylated genomic DNA is protected from the action of the cognate restriction enzyme, while nonmethylated DNA from other lytic or lysogenic bacteriophages is restricted so that it cannot kill or sabotage the survival of the bacteria (58). This suggests another example of how ⌽10394.4 may increase host strain survival in the population and provides another reason why erythromycin-resistant isolates carrying mefA are increasing in the streptococcal population (25,27,44,52). In fact, analysis of DNA sequences from 23 of the published lysogenic bacteriophages of S. pyogenes show that they contain an average of 17 CCNGG sites in their genomes (data not shown) (2,4,19,53).…”

“…The treatment of choice for streptococcal pharyngitis infections is penicillin V (8), but in recent years, macrolide antibiotics, such as azithromycin and erythromycin, have been increasingly prescribed as alternative treatments (14,16,23,33). Concomitantly, there has been an increase in macrolideresistant strains of S. pyogenes (5,12,14,25,36), posing a global health problem for patients who are hypersensitive to ␤-lactam antibiotics (8,48,57).…”

“…The mefA gene is present in a number of phylogenetically unrelated serotypes of S. pyogenes (5,12,25,36) and in some regions of the world is becoming the predominant erythromycin resistance determinant in streptococcal isolates (25,27,44,52). Earlier studies suggested that erythromycin resistance and the mefA gene may be acquired through horizontal gene transfer; however, at that time, the mechanisms were not clearly identified in S. pyogenes (17,27,34).…”

Detection of Multiple Macrolide- and Lincosamide-Resistant Strains of Streptococcus pyogenes from Patients in the Boston Area

“…Widespread use of macrolide antibiotics appears to have selected for high levels (Ͼ10%) of macrolide and lincosamide resistance in several countries in Europe and Asia (5,12,(17)(18)(19). Recent Infectious Diseases Society of America guidelines for the treatment of S. pyogenes pharyngitis recommend the use of penicillin for patients who are not allergic to penicillin (4).…”