title: Multilocus sequence types of invasive and colonizing neonatal group B streptococci in Poland.
abstract: OBJECTIVE
  The present study aimed to investigate the molecular characterization of Streptococcus agalactiae (group B streptococcus; GBS) strains isolated from newborns with invasive neonatal infections and healthy newborns in Poland.
  
  
  METHODS
  Forty-two GBS isolates were characterized by combining different typing methods, i.e. multilocus sequence typing (MLST), molecular serotyping and protein gene profiling.
  
  
  RESULTS
  Using MLST, a total of 16 sequence types (STs) were identified, and among these, 11 were clustered into the following 5 clonal complexes (CCs): CC23 (20; 49%), CC19 (7; 17%), CC17 (4; 10%), CC10 (4; 10%) and CC1 (1; 2%). A statistically significant relationship between ST-17 and invasive isolates (p = 0.0398) and ST-23 and colonizing strains (p = 0.0034) was detected. Moreover, 2 novel STs were detected (ST-637 and ST-638). Molecular serotyping showed that in the invasive isolates serotype III was predominant (11; 50%), followed by serotypes II (6; 27%), V (3; 14%) and Ia (2; 9%). In healthy newborns, serotype III was also dominant (12; 60%), followed by serotypes Ia (4; 20%), II (2; 10%), V (1; 5%) and Ib (1; 5%). Protein gene profiling indicated that the rib gene was predominant in the invasive strains (11; 59%), followed by bca (5; 22%), alp2 (2; 9%), alp3 (1; 5%) and epsilon (1; 5%), while in colonizing strains the alp2 gene was most common (10; 50%), followed by epsilon (5; 25%), rib (2; 10%), bca (2; 10%) and alp3 (1; 5%). A statistically significant relationship was noted between the rib gene and invasive GBS (p = 0.0329), whereas alp2 was related to the colonizing strains (p = 0.0495).
  
  
  CONCLUSIONS
  The investigated GBS isolates originating from infections in newborns and healthy neonates represented serotype III in more than half of the cases and differed from one another in terms of resistance to macrolides, ST type affiliation and the presence of genes encoding surface proteins from the Alp family. Further comparative genetic research on a larger number of strains is necessary for epidemiological investigation and vaccine development.
authors.affiliation: Department of Bacteriology, Microbial Ecology and Parasitology, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Brzychczy-Wloch
authors.forename: Tomasz
authors.initials: T
authors.lastname: Gosiewski
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Bulanda
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D058885:Multilocus Sequence Typing; D011044:Poland; D012703:Serotyping; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents