title: High Incidence of Macrolide and Tetracycline Resistance among Streptococcus Agalactiae Strains Isolated from Clinical Samples in Tehran, Iran.
abstract: BACKGROUND
  Streptococcus agalactiae or Group B Streptococci (GBS) is an important bacterial pathogen that causes a wide range of infections including neonatal sepsis, meningitis, pneumonia and soft tissue or urinary tract infections.
  
  
  METHODS
  One hundred and fifteen isolates of Streptococcus agalactiae collected from urine specimens of patients attending a hospital in Tehran. All isolates were screened for their capsular types and genes encoding resistance to the macrolide and tetracycline antibiotics by PCR and multiplex PCR-based methods.
  
  
  RESULTS
  Most of isolates belonged to capsular types III (49%), V (19%), II (16%), and Ib (6%). Twelve isolates (10%) were nontypable. All isolates were susceptible to penicillin and Quinupristin-dalfopristin, but were resistant to clindamycin (35%), chloramphenicol (45%), erythromycin (35%), linezolid (1%) and tetracycline (96%). The most prevalent antimicrobial resistance gene was tetM found in 93% of the isolates followed by ermTR, ermB, and tetK, found in 23%, 16%, and 16% of isolates, respectively. The genes, tetL, tetO, ermA, ermC and mefA were not detected in any of the S. agalactiae isolates. Of the 110 tetracycline resistant S. agalactiae, 89 isolates harbored the tetM gene alone and eighteen isolates carried the tetM gene with the tetK gene. All erythromycin-resistant isolates exhibited cMLSB resistance phenotype, 22 isolates harbored the ermTR gene alone and five isolates carried the ermTR gene with the ermB gene. The rate of coexistence of genes encoding the erythromycin and tetracycline resistance determinants was 34%.
  
  
  CONCLUSIONS
  The present study demonstrated that S. agalactiae isolates obtained from urine samples showed a high rate of resistance to tetracycline, chloramphenicol and macrolide antibiotics and were commonly associated with the resistance genes temM, ermTR or ermB.
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Emaneini
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Mirsalehian
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Beigvierdi
authors.affiliation: Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Abbas Ali Imani
authors.initials: AA
authors.lastname: Fooladi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Asadi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Jabalameli
authors.affiliation: Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.
authors.forename: Morovat
authors.initials: M
authors.lastname: Taherikalani
keywords: Streptococcus agalactiae; capsular type; ermTR; tetM