Prevalence of Polyclonal mefA -Containing Isolates among Erythromycin-Resistant Group A Streptococci in Southern Taiwan

Abstract

A total of 204 nonrepetitive isolates of group A streptococci (GAS), including 107 randomly collected between 1992 and 1995 and 66 and 31 consecutively collected in 1997 and 1998, respectively, from a university hospital in southern Taiwan were examined to determine the prevalence and mechanisms of erythromycin resistance among these isolates. Resistance to erythromycin was detected in 129 isolates (63.2%) by the agar dilution test. Of these, 42 isolates (32.6%) were assigned to the constitutive macrolide, lincosamide, and streptogramin B resistance (cMLS) phenotype, and all carried the ermBgene; 4 (3.1%) were assigned to the inducible MLS resistance (iMLS) phenotype, and all harbored the ermTR gene; and 83 (64.3%) were erythromycin resistant but susceptible to clindamycin (M phenotype), and all possessed the mefA gene. Distributed by years, the rates of erythromycin resistance and different phenotypes were 61.7% (53.0% cMLS, 6.1% iMLS, and 40.9% M phenotype) between 1992 and 1995, 62.1% (12.2% cMLS and 87.8% M phenotype) in 1997, and 71.0% (9.1% cMLS and 90.9% M phenotype) in 1998. Pulsed-field gel electrophoresis showed that all but 2 cMLS isolates were clonal in origin, and 17 clones were detected among the M-phenotype isolates. These results indicate that the high incidence and increasing rate of erythromycin-resistant GAS in southern Taiwan are due to the prevalence of multiple M-phenotype clones and that clindamycin may be the drug of choice for the treatment of infections with GAS in penicillin-hypersensitive patients in this area.

Predominance of two M-types among erythromycin-resistant group A Streptococci from Greek children

“…Similar results were obtained from studies in Italy, Canada and a multicenter study from Finland [15,16,22]. However, in studies from Taiwan and Belgium, where the M phenotype was also dominant, the IR phenotype was less frequently observed than the CR phenotype [14,19]. Nevertheless, the prevalence of the M phenotype in the present study was higher than in a previous Greek study (52%) [5], possibly suggesting an increasing trend in presumably mef A‐expressing isolates.…”

“…Macrolide resistance seems to be a major problem in defined geographic areas. In Spain, Italy, Finland, Germany and Taiwan resistance rates of 12.1% to 63.2% have been reported [2,3,7,13–15]. More specifically, in Spain, an increase in macrolide resistance from 1.1% in 1986 to 29.3% in 1997 has been documented [3].…”

“…In Canada and France [16,17], serotype M4 was also dominant among M‐phenotype EryR isolates, but no data on serotype prevalence among EryS isolates were reported. The predominance of specific types among EryR isolates has also been documented using a molecular typing method, pulsed field gel electrophoresis [13,14,21].…”

Changes in macrolide resistance among respiratory pathogens after decreased erythromycin consumption in Taiwan

“…However, a similar M phenotype distribution was not found in S. pneumoniae [6]. Disappearance of one or more clones of highly erythromycin‐resistant S. pyogenes in the community might account for the overall reduction in resistance [9,10].…”

Arrangement and number of clustered regularly interspaced short palindromic repeat spacers are associated with erythromycin susceptibility in emm12, emm75 and emm 92 of group A streptococcus

“…A total of 330 GAS isolates were collected at National Cheng Kung University Hospital in southern Taiwan during 1997-2003. Strain characterization, including identification, emm typing, pulsed-field gel electrophoresis, antibiotic susceptibility and erythromycin-resistant gene detection, was carried out as in previous studies [9,17,24]. The detailed information on emm4, emm12, emm75 and emm92 strains is listed in the Supplementary material (Table S1).…”