Brzychczy-Wloch Monika, Gosiewski Tomasz, Bulanda Malgorzata
Department of Bacteriology, Microbial Ecology and Parasitology, Jagiellonian University Medical College, Krakow, Poland.
Med Princ Pract. 2014;23(4):323-30. doi: 10.1159/000362368. Epub 2014 May 7.
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.
Forty-two GBS isolates were characterized by combining different typing methods, i.e. multilocus sequence typing (MLST), molecular serotyping and protein gene profiling.
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).
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.
本研究旨在调查从波兰患有侵袭性新生儿感染的新生儿和健康新生儿中分离出的无乳链球菌（B组链球菌；GBS）菌株的分子特征。
通过结合多种分型方法，即多位点序列分型（MLST）、分子血清分型和蛋白质基因谱分析，对42株GBS分离株进行特征分析。
使用MLST共鉴定出16种序列类型（STs），其中11种聚为以下5个克隆复合体（CCs）：CC23（20株；49%）、CC19（7株；17%）、CC17（4株；10%）、CC10（4株；10%）和CC1（1株；2%）。检测到ST-17与侵袭性分离株之间存在统计学显著关系（p = 0.0398），ST-23与定植菌株之间存在统计学显著关系（p = 0.0034）。此外，还检测到2种新的STs（ST-637和ST-638）。分子血清分型显示，侵袭性分离株中血清型III占主导（11株；50%），其次是血清型II（6株；27%）、V（3株；14%）和Ia（2株；9%）。在健康新生儿中，血清型III也占主导（12株；60%），其次是血清型Ia（4株；20%）、II（2株；10%）、V（1株；5%）和Ib（1株；5%）。蛋白质基因谱分析表明，侵袭性菌株中rib基因占主导（11株；59%），其次是bca（5株；22%）、alp2（2株；9%）、alp3（1株；5%）和epsilon（1株；5%），而定植菌株中alp2基因最常见（10株；50%），其次是epsilon（5株；25%）、rib（2株；10%）、bca（2株；10%）和alp3（1株；5%）。rib基因与侵袭性GBS之间存在统计学显著关系（p = 0.0329），而alp2与定植菌株相关（p = 0.0495）。
所调查的源自新生儿感染和健康新生儿的GBS分离株在半数以上病例中为血清型III，在对大环内酯类药物的耐药性、ST型归属以及来自Alp家族的表面蛋白编码基因的存在方面彼此不同。为进行流行病学调查和疫苗开发，有必要对更多菌株进行进一步的比较遗传学研究。
