Fusidic acid and clindamycin resistance in community-associated, methicillin-resistant Staphylococcus aureus infections in children of Central Greece.

INTRODUCTION: In Greece, fusidic acid and clindamycin are commonly used for the empiric therapy of suspected staphylococcal infections. METHODS: The medical records of children examined at the outpatient clinics or admitted to the pediatric wards of the University General Hospital of Larissa, Central Greece, with community-associated staphylococcal infections from January 2003 to December 2009 were reviewed. RESULTS: Of 309 children (0-14 years old), 21 (6.8%) had invasive infections and 288 (93.2%) skin and soft tissue infections (SSTIs). Thirty-five patients were ≤30 days of age. The proportion of staphylococcal infections caused by a community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolate increased from 51.5% (69 of 134) in 2003-2006 to 63.4% (111 of 175) in 2007-2009 (P = 0.037). Among the CA-MRSA isolates, 88.9% were resistant to fusidic acid, 77.6% to tetracycline, and 21.1% to clindamycin. Clindamycin resistance increased from 0% (2003) to 31.2% (2009) among the CA-MRSA isolates (P = 0.011). Over the 7-year period, an increase in multidrug-resistant CA-MRSA isolates was observed (P = 0.004). One hundred and thirty-one (93.6%) of the 140 tested MRSA isolates were Panton-Valentine leukocidin-positive. Multilocus sequence typing of 72 CA-MRSA isolates revealed that they belonged to ST80 (n = 61), ST30 (n = 6), ST377 (n = 3), ST22 (n = 1), and ST152 (n = 1). Resistance to fusidic acid was observed in ST80 (58/61), ST30 (1/6), and ST22 (1/1) isolates. CONCLUSION: In areas with high rate of infections caused by multidrug-resistant CA-MRSA isolates, predominantly belonging to the European ST80 clone, fusidic acid and clindamycin should be used cautiously as empiric therapy in patients with suspected severe staphylococcal infections.

Antimicrobial use and serotype distribution of nasopharyngeal Streptococcus pneumoniae isolates recovered from Greek children younger than 2 years old.

The serotype distribution of 781 nasopharyngeal pneumococcal isolates recovered from 2448 unselected children aged 2-23 months was studied. Only 3.9% of the children for whom cultures were performed attended day care centers. The proportions of pneumococcal isolates that belonged to serotypes related to the 7-, 9- and 11-valent conjugate pneumococcal vaccine were 65%, 66%, and 70%, respectively. The pneumococcal carriage rate among untreated children was 34%; the rates among children treated with antibiotics during the periods 1-30 or 31-60 days before the time of nasopharyngeal sampling were 25% and 36%, respectively. There was a significant positive association between antimicrobial use and carriage of antibiotic-resistant pneumococci, which belonged mainly to vaccine-related serotypes. The proportion of isolates that belonged to vaccine-related serotypes in untreated carriers was 72%; however, the proportions in carriers treated 1-30 days or 31-60 days before sampling were 66% and 56%, respectively. In the nasopharynx, antimicrobial use selects for antibiotic-resistant pneumococci, mainly of vaccine-related serotypes, whereas it may promote an increase in the frequency of colonization with nonvaccine serotypes.

Two dosages of clarithromycin for five days, amoxicillin/clavulanate for five days or penicillin V for ten days in acute group A streptococcal tonsillopharyngitis.

BACKGROUND: Short course antimicrobial therapy is suggested for group A streptococcal tonsillopharyngitis. METHODS: The bacteriologic and clinical efficacies of clarithromycin [30 or 15 mg/kg/day twice daily (b.i.d.)] or amoxicillin/clavulanate (43.8/6.2 mg/kg/day b.i.d.) for 5 days or penicillin V (30 mg/kg/day 3 times a day) for 10 days were compared. In a randomized, open label, parallel group, multicenter study, 626 children (2-16 years old) with tonsillopharyngitis were enrolled; 537 were evaluable for efficacy. Follow-up evaluations were performed at 4-8 and 21-28 days after therapy. RESULTS: At enrollment, 26% of the Streptococcus pyogenes isolates were clarithromycin-nonsusceptible. All regimens had an apparently similar clinical efficacy. The long term S. pyogenes eradication rates were 102 of 123 (83%) with amoxicillin/clavulanate and 88 of 114 (77%) with penicillin V. In the 30- and 15-mg/kg/day clarithromycin groups, eradication occurred in 71 of 86 (83%) and 59 of 80 (74%) of the clarithromycin-susceptible isolates (P = 0.33), and in 4 of 28 (14%) and 5 of 26 (19%) of the clarithromycin-resistant isolates, respectively (clarithromycin-susceptible versus -resistant, P < 0.0001). Both clarithromycin dosages were well-tolerated. CONCLUSIONS: In group A streptococcal tonsillopharyngitis, 5 days of clarithromycin or amoxicillin/clavulanate treatment had clinical efficacy comparable with that of 10 days of penicillin V treatment; however, amoxicillin/clavulanate and penicillin V were bacteriologically more effective than clarithromycin because of its failure to eradicate the clarithromycin-resistant S. pyogenes isolates. The 5-day clarithromycin regimens are not recommended for treatment of streptococcal tonsillopharyngitis in areas where in vitro resistance of group A streptococci to clarithromycin is common.

Resistance to erythromycin and telithromycin in Streptococcus pyogenes isolates obtained between 1999 and 2002 from Greek children with tonsillopharyngitis: phenotypic and genotypic analysis.

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, > or = 2 microg/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.

Antimicrobial susceptibility and macrolide resistance inducibility of Streptococcus pneumoniae carrying erm(A), erm(B), or mef(A).

Erythromycin-resistant Streptococcus pneumoniae isolates from young carriers were tested for their antimicrobial susceptibility; additionally, inducibility of macrolide and clindamycin resistance was investigated in pneumococci carrying erm(A), erm(B), or mef(A). Of 125 strains tested, 101 (81%) were multidrug resistant. Different levels of induction were observed with erythromycin, miocamycin, and clindamycin in erm(B) strains; however, in erm(A) strains only erythromycin was an inducer. Induction did not affect macrolide MICs in mef(A) strains.