title: Phenotypic and genotypic characterization of Streptococcus pneumoniae resistant to macrolide in Casablanca, Morocco.
abstract: In Morocco, the 13-valent pneumococcal conjugate vaccine (PCV-13) was introduced in the national immunization program (NIP) in October 2010 and replaced by the PCV-10 in July 2012. The present study aimed to determine the prevalence of erythromycin-resistant Streptococcus pneumoniae (ERSP) and to analyze the phenotypic and genotypic characteristics of these isolates in Casablanca, Morocco from January 2007 to December 2014. Isolates were obtained from the Microbiology Laboratory of Ibn Rochd University Hospital Centre of Casablanca. Serogrouping was done using Pneumotest Kit and serotyping by the Quellung capsular swelling. Antibiotic susceptibility pattern was determined by disk diffusion and Etest methods. A total of 655S. pneumoniae isolates were collected from 2007 to 2014 from pediatric and adult patients. Fifty-five percent of these isolates were from invasive pneumococcal diseases. Of the 655 isolates, 92 (14%) were ERSP. Globally, the proportion of ERSP from 2007 to 2010 (before vaccination) and from 2011 to 2014 (after vaccination) were 11.6% and 17.2% (p=0.04), respectively. Of the 92 ERSP, 89%, 4% and 7% displayed constitutive MLSB (resistance to macrolide, lincosamide and streptogramin B), inducible MLSB, and M phenotype (resistance to macrolide only), respectively. ERSP genotypic analysis showed that 90.2% carried the ermB gene, 6.5% the mefE gene, and 3.3% both the genes (ermB+mefE). The most prevalent ERSP serotypes were 6B, 19F and 23F before vaccination and 19F, 6B, 6A and 23F after vaccination. Erythromycin resistance among S. pneumoniae is relatively high in Casablanca. The contribution of PCVs to the reduction in antibiotic use is encouraging but this should be accompanied by a rational use of antibiotic.
authors.affiliation: Laboratoire de Microbiologie, Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, B.P 9154, Casablanca, Maroc; Service de Microbiologie, CHU Ibn Rochd, Casablanca, Maroc. Electronic address: diawaraidris@gmail.com.
authors.forename: Idrissa
authors.initials: I
authors.lastname: Diawara
authors.affiliation: Laboratoire de Microbiologie, Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, B.P 9154, Casablanca, Maroc; Service de Microbiologie, CHU Ibn Rochd, Casablanca, Maroc. Electronic address: khalid.zerouali2000@gmail.com.
authors.forename: Khalid
authors.initials: K
authors.lastname: Zerouali
authors.affiliation: Service de Microbiologie, CHU Ibn Rochd, Casablanca, Maroc. Electronic address: khalidkatfy@hotmail.com.
authors.forename: Khalid
authors.initials: K
authors.lastname: Katfy
authors.affiliation: Laboratoire de Microbiologie, Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, B.P 9154, Casablanca, Maroc; Molecular Bacteriology Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco. Electronic address: dihaj82@yahoo.fr.
authors.forename: Abouddihaj
authors.initials: A
authors.lastname: Barguigua
authors.affiliation: Laboratoire de Microbiologie, Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, B.P 9154, Casablanca, Maroc; Service de Microbiologie, CHU Ibn Rochd, Casablanca, Maroc. Electronic address: belhor2001@yahoo.fr.
authors.forename: Houria
authors.initials: H
authors.lastname: Belabbes
authors.affiliation: Molecular Bacteriology Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco. Electronic address: mohammed.timinouni@pasteur.ma.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Timinouni
authors.affiliation: Laboratoire de Microbiologie, Faculté de Médecine et de Pharmacie, Hassan II University of Casablanca, B.P 9154, Casablanca, Maroc; Service de Microbiologie, CHU Ibn Rochd, Casablanca, Maroc. Electronic address: naimaelmdaghri@yahoo.fr.
authors.forename: Naima
authors.initials: N
authors.lastname: Elmdaghri
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004917:Erythromycin / Q000494:pharmacology; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018942:Macrolides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009018:Morocco / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D015995:Prevalence; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects* / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D018942:Macrolides; D004917:Erythromycin
keywords: Macrolides resistance; Pneumococcal conjugate vaccine; Streptococcus pneumoniae; ermB; mefE