Description of macrolide-resistant and potential virulent clones of Streptococcus pyogenes causing asymptomatic colonization during 2000–2006 in the Lisbon area

• Published in: European journal of clinical microbiology & infectious diseases Vol. 31; no. 5; pp. 849 - 857
• Main Authors: Pires, R., Rolo, D., Morais, A., Brito-Avô, A., Johansson, C., Henriques-Normark, B., Gonçalo-Marques, J., Santos-Sanches, I.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-05-2012; Springer; Springer Nature B.V
• Subjects: Adolescent; Adult; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antigens, Bacterial - genetics; Asymptomatic; Bacterial Outer Membrane Proteins - genetics; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Carrier Proteins - genetics; Carrier State - epidemiology; Carrier State - microbiology; Child; Child, Preschool; Children; Cloning; Cluster Analysis; Colonization; DNA methylation; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Epidemiology; Evolution; Families & family life; Gene transfer; Genes; Genotype; Genotypes; Health care; Households; Humans; Infant; Infection; Infections; Infectious diseases; Internal Medicine; Macrolides - pharmacology; Medical Microbiology; Medical sciences; Medicin och hälsovetenskap; Molecular Epidemiology; Multilocus Sequence Typing; Niches; Oropharynx - microbiology; Penicillin; Pharmacology. Drug treatments; Portugal - epidemiology; Prevalence; Respiratory tract; Streptococcal Infections - epidemiology; Streptococcal Infections - microbiology; Streptococcus pyogenes; Streptococcus pyogenes - classification; Streptococcus pyogenes - drug effects; Streptococcus pyogenes - isolation & purification; Streptococcus pyogenes - pathogenicity; Virulence; Virulence Factors - genetics; Portugal; Sweden; Minimum Inhibitory Concentration; Necrotizing Fasciitis; Macrolide Resistance; PFGE Cluster; Antimicrobial Consumption; Infection; Streptococcaceae; Microbiology; Bacteria; Micrococcales; Streptococcus pyogenes; Asymptomatic; Protein synthesis inhibitor; Antibacterial agent; Macrolide; Colonization
• ISSN: 0934-9723; 1435-4373; 1435-4373
• DOI: 10.1007/s10096-011-1384-x

The asymptomatic oropharyngeal colonization rate by
Streptococcus pyogenes
was 10.7% in children (901 among 8,405 children 0–16 years old) and 3.3% in adults (37 among 1,126 households of children) in the Lisbon area during 2000–2006. Macrolide-resistant
S. pyogenes
from children (
n
 = 149) was variable with time: 9.8–10.7% in 2000–2002, 28.1% in 2003, 19.6–2.7% in 2004–2005 and 14.6% in 2006. Eight lineages (97.3% of isolates) were identified based on at least 80% similarity of PFGE patterns, T types,
emm
types and multilocus sequence types (ST). The elevated frequency of macrolide resistance was associated with M phenotype lineages I (
emm
12/ST36) and V (
emm
4,
emm
75/ST39 and a novel
emm
stMrp6 type) and with one cMLS
B
lineage IV (
emm
28/ST52) known to be associated with upper respiratory tract and invasive infections. Significant associations (
p
 < 0.05) between
emm
type/virulence genotype were found, such as
emm
1/
speA
+
ssa
-
,
emm
4/
ssa
+
prtF1
+
,
emm
12/
speA
-
ssa
-
. The high prevalence (>20%) of
speC
,
prtF1
or
ssa
was probably caused either by clonal dissemination (
speC
), or to horizontal gene transfer events (
prtF1
and
ssa
). This report contributes to a better understanding of the molecular epidemiology and evolution of macrolide-resistant
S. pyogenes
causing symptom-free oropharyngeal colonization. These colonizing strains carry macrolide resistance and virulence genes capable of being transferred to other bacterial species sharing the same niche.