Fatma Nur Akdoğan Kittana1, Inci Basak Mustak2, Gulsen Hascelik1, Seyyide Saricam2, Nezahat Gurler3, Kadir Serdar Diker2. 1. 1 Hacettepe University, Faculty of Medicine, Department of Medical Microbiology, Ankara, Turkey. 2. 2 Ankara University, Faculty of Veterinary Science, Department of Microbiology, Ankara Turkey. 3. 3 Istanbul University, Faculty of Medicine, Department of Medical Microbiology, Istanbul, Turkey.
Abstract
PURPOSE: To assess the antibiotic resistance, transposon profiles, serotype distribution and vaccine coverage rates in 110 erythromycin-resistant S. pneumoniae clinical isolates. METHODOLOGY: Erythromycin, clindamycin, tetracycline, chloramphenicol and kanamycin susceptibilities were assessed using the E-test/disc diffusion method. Inducible macrolide resistance was tested using the erythromycin-clindamycin double disc diffusion test. Serogrouping and serotyping were performed using latex particle agglutination and the Quellung reaction, respectively. Drug resistance genes and transposon-specific genes were investigated by PCR. RESULTS: Of the isolates, 93 % were resistant to clindamycin; 81 % were resistant to tetracycline; 76 % were multi-drug-resistant, having resistance to both clindamycin and tetracycline; and 12 % had extended-drug resistance, being resistant to clindamycin, tetracycline, chloramphenicol and kanamycin. The majority of isolates (88.2 %) exhibited the cMLSB phenotype. The association between the cMLSB phenotype and tetracycline resistance was related to transposons Tn2010 (38.2 %), Tn6002 (21.8 %) and Tn3872 (18.2 %). M and iMLSB phenotypes were observed in 7 and 5 % of the isolates, respectively. The most frequent serotype was 19 F (40 %). Among the erythromycin-resistant pneumococci, vaccine coverage rates for the 13-valent pneumococcal conjugate vaccine (PCV-13) and the 23-valent pneumococcal polysaccharide vaccine (PPSV-23) were 76.4 and 79.1 %, respectively, compared to 82.2 and 85.1 % transposon-carrying isolates. CONCLUSIONS: Multi-drug resistance among erythromycin-resistant S. pneumoniae isolates mainly occurs due to the horizontal spread of the Tn916 family of transposons. The majority of the transposon-carrying isolates are covered by 13- and 23-valent pneumococcal vaccines. Since serotype distribution and transposons in S. pneumoniae isolates may change over time, close monitoring is essential.
PURPOSE: To assess the antibiotic resistance, transposon profiles, serotype distribution and vaccine coverage rates in 110 erythromycin-resistant S. pneumoniae clinical isolates. METHODOLOGY:Erythromycin, clindamycin, tetracycline, chloramphenicol and kanamycin susceptibilities were assessed using the E-test/disc diffusion method. Inducible macrolide resistance was tested using the erythromycin-clindamycin double disc diffusion test. Serogrouping and serotyping were performed using latex particle agglutination and the Quellung reaction, respectively. Drug resistance genes and transposon-specific genes were investigated by PCR. RESULTS: Of the isolates, 93 % were resistant to clindamycin; 81 % were resistant to tetracycline; 76 % were multi-drug-resistant, having resistance to both clindamycin and tetracycline; and 12 % had extended-drug resistance, being resistant to clindamycin, tetracycline, chloramphenicol and kanamycin. The majority of isolates (88.2 %) exhibited the cMLSB phenotype. The association between the cMLSB phenotype and tetracycline resistance was related to transposons Tn2010 (38.2 %), Tn6002 (21.8 %) and Tn3872 (18.2 %). M and iMLSB phenotypes were observed in 7 and 5 % of the isolates, respectively. The most frequent serotype was 19 F (40 %). Among the erythromycin-resistant pneumococci, vaccine coverage rates for the 13-valent pneumococcal conjugate vaccine (PCV-13) and the 23-valent pneumococcalpolysaccharide vaccine (PPSV-23) were 76.4 and 79.1 %, respectively, compared to 82.2 and 85.1 % transposon-carrying isolates. CONCLUSIONS: Multi-drug resistance among erythromycin-resistant S. pneumoniae isolates mainly occurs due to the horizontal spread of the Tn916 family of transposons. The majority of the transposon-carrying isolates are covered by 13- and 23-valent pneumococcal vaccines. Since serotype distribution and transposons in S. pneumoniae isolates may change over time, close monitoring is essential.
Authors: Elissavet Nikolaou; Alasdair T M Hubbard; João Botelho; Taylor A M Marschall; Daniela M Ferreira; Adam P Roberts Journal: Genes (Basel) Date: 2020-06-06 Impact factor: 4.096