Streptococcus agalactiae from pregnant women: antibiotic and heavy-metal resistance mechanisms and molecular typing

• Published in: Epidemiology and infection Vol. 144; no. 15; pp. 3205 - 3214
• Main Authors: ROJO-BEZARES, B., AZCONA-GUTIÉRREZ, J. M., MARTIN, C., JAREÑO, M. S., TORRES, C., SÁENZ, Y.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01-11-2016
• Subjects: Adolescent; Adult; Agar; Age; Aminoglycosides; Amplification; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; Antimicrobial agents; Antimicrobial resistance; Antiseptics; Assaying; Azithromycin; Bacteria; Biochemistry; Cadmium; Chemotherapy; Colonies; Copper; Dilution; Disinfection; Disks; Drug Resistance, Bacterial - genetics; Environmental control; Epidemiology; Female; Fungicides; Gastrointestinal tract; Genes; Gestation; Heavy metals; Humans; Infectious diseases; Lincosamides - pharmacology; Macrolides - pharmacology; Meningitis; Metals, Heavy - toxicity; Microbiology; Middle Aged; Nucleotide sequence; Older people; Operons; Original Papers; Penicillin; Population structure; Pregnancy; Preservatives; Proteins; Rectum; Reproductive sterilization; Spain - epidemiology; Streptococcal Infections - epidemiology; Streptococcal Infections - microbiology; Streptococci; Streptococcus; Streptococcus agalactiae - drug effects; Streptococcus agalactiae - genetics; Streptococcus agalactiae - pathogenicity; Streptococcus agalactiae - physiology; Streptococcus infections; Tropism; Vaccines; Virulence - drug effects; Virulence - genetics; Virulence Factors - genetics; Womens health; Young Adult; United States > US; Germany; Spain; streptococcal infections; Antibiotic resistance; bacterial typing
• ISSN: 0950-2688; 1469-4409
• DOI: 10.1017/S0950268816001692

We investigated the antibiotic and heavy-metal resistance mechanisms, virulence genes and clonal relationships of macrolide- and/or lincosamide-resistant (M+/−LR) Streptococcus agalactiae (group B Streptococcus, GBS) isolates from pregnant women in La Rioja in Northern Spain, a region with a significant immigrant population. In total 375 GBS isolates were recovered during 2011. About three-quarters of isolates were from European nationals and the remainder distributed among 23 other nationalities. Seventy-five (20%) were classified as M+/−LR strains and 28 (37%) of these were resistant to ⩾3 classes of antibiotics. Capsular serotypes III (29·3%), V (21·3%) and II (12%) were the most frequent. A wide variety of antibiotic resistance genes were detected in M+/−LR strains; notably, 5·3% harboured the lsa(C) gene associated with cross-resistance, and tet(W) was identified in a single strain. We report, for the first time, the detection of cadmium and copper resistance encoded by tcrB + cadA + cadC genes in 20 M+/−LR strains, which raises the possibility of co-selection of antibiotic and heavy-metal resistance disseminated through mobile genetic elements. The M+/−LR strains were highly diverse by DNA macrorestriction profiles (65 patterns) and 16 multilocus sequence types (STs) distributed among six clonal complexes; the most frequent were ST1, ST19, and ST12, and two strains were novel (ST586 and ST601). In conclusion, a wide diversity of genetic lineages of macrolide, lincosamide and heavy-metal- resistant GBS strains was observed in an ethnically diverse maternal population.