Affiliation:
1. Microbiology Department, Hospital Universitari de Bellvitge, University of Barcelona, IDIBELL, Barcelona, Spain
2. Ciber de Enfermedades Respiratorias, ISCIII, Madrid, Spain
3. Microbiology Department, Hospital Gregorio Marañón, Madrid, Spain
4. Microbiology Department, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
5. Infectious Diseases Department, Clinical Research Unit, Hospital Universitari de Bellvitge, University of Barcelona, IDIBELL, Barcelona, Spain
Abstract
ABSTRACT
The aim of this study was to analyze the distributions of antibiotic susceptibility patterns, serotypes, phenotypes, genotypes, and macrolide resistance genes among 125 nonduplicated erythromycin-resistant
Streptococcus pneumoniae
clinical isolates collected in a Spanish point prevalence study. The prevalence of resistance to macrolides in this study was 34.7%. Multiresistance (to three or more antimicrobials) was observed in 81.6% of these strains. Among 15 antimicrobials studied, cefotaxime, moxifloxacin, telithromycin, and quinupristin-dalfopristin were the most active drugs. The most frequent serotypes of erythromycin-resistant isolates were 19F (25%), 19A (17%), 6B (12%), 14 (10%), and 23F (10%). Of the 125 strains, 109 (87.2%) showed the MLS
B
phenotype [103 had the
erm
(B) gene and 6 had both
erm
(B) and
mef
(E) genes]. Sixteen (12.8%) strains showed the M phenotype [14 with
mef
(E) and 2 with
mef
(A)]. All isolates were tested by PCR for the presence of the
int, xis, tnpR
, and
tnpA
genes associated with conjugative transposons (Tn
916
family and Tn
917
). Positive detection of
erm
(B),
tet
(M),
int
, and
xis
genes related to the Tn
916
family was found in 77.1% of MLS
B
phenotype strains. In 16 strains, only the
tndX, erm
(B), and
tet
(M) genes were detected, suggesting the presence of Tn
1116
, a transposon recently described for
Streptococcus pyogenes
. Five clones, namely, Sweden
15A
-25, clone
19F
ST87, Spain
23F
-1, Spain
6B
-2, and clone
19A
ST276, accounted for half of the MLS
B
strains. In conclusion, the majority of erythromycin-resistant pneumococci isolated in Spain had the MLS
B
phenotype, belonged to multiresistant international clones, and carried the
erm
(B),
tet
(M),
xis
, and
int
genes, suggesting the spread of transposons of the Tn
916
family.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology