Department of Laboratory Medicine, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Department of Laboratory Medicine, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, 530021, China.
BMC Infect Dis. 2019 Sep 9;19(1):791. doi: 10.1186/s12879-019-4413-5.
Infections by Streptococcus gallolyticus subsp. pasteurianus (SGSP) is often underestimated. Herein, the epidemiological features and resistant characteristics of SGSP in mainland China are characterized to enable a better understanding of its role in clinical infections.
In the present work, 45 SGSP isolates were collected from the samples of bloodstream, urine, aseptic body fluid, and fetal membrane/placenta from patients in 8 tertiary general hospitals of 6 cities/provinces in China from 2011 to 2017. The identification of all isolates was performed using traditional biochemical methods, 16S rRNA and gyrB sequencing, followed by the characterization of their antibiotic resistance profiling and involved genes.
Among 34 non-pregnancy-related patients, 4 (4/34,11.8%) patients had gastrointestinal cancer, 10 (10/34, 29.4%) patients had diabetes, and one patient had infective endocarditis. Moreover, 11 cases of pregnant women were associated with intrauterine infection (9/11, 81.2%) and urinary tract infection (1/11, 9.1%), respectively. Except one, all other SGSP isolates were correctly identified by the BD Phoenix automated system. We found that all SGSP isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, meropenem, and vancomycin. Forty strains (40/45, 88.9%) were both erythromycin and clindamycin-resistant, belonging to the cMLS phenotype, and the majority of them carried erm(B) gene (39/40, 97.5%). Although the cMLS/erm(B) constituted the most frequently identified phenotype/genotype combination (25/40, 62.5%) among all erythromycin-resistant cMLS isolates, erm(B)/erm(A), erm(B)/mef(A/E), and erm(B)/erm(T) was detected in 7, 4, and 3 isolates, respectively. Furthermore, 43 strains (43/45, 95.6%) were tetracycline-resistant, and out of these, 39 strains (39/45, 86.7%) carried tet(L), 27(27/45, 60.0%) strains carried tet(O), and 7 (7/45, 15.6%) strains carried tet(M), alone or combined, respectively. All erythromycin-resistant isolates were also resistant to tetracycline.
It is important to study and draw attention on SGSP, an underreported opportunistic pathogen targeting immunodeficient populations, notably elderly subjects, pregnant women and neonates.
化脓性链球菌亚种 pasteurianus (SGSP) 感染常常被低估。本研究旨在描述中国大陆 SGSP 的流行病学特征和耐药特征，以更好地了解其在临床感染中的作用。
本研究从 2011 年至 2017 年中国大陆 6 个城市/省份的 8 家三级综合医院的血流、尿液、无菌体液和胎膜/胎盘样本中收集了 45 株 SGSP 分离株。所有分离株的鉴定均采用传统的生化方法、16S rRNA 和 gyrB 测序，然后对其抗生素耐药谱和相关基因进行表征。
在 34 例非妊娠相关患者中，4 例（4/34，11.8%）患者患有胃肠道癌，10 例（10/34，29.4%）患者患有糖尿病，1 例患者患有感染性心内膜炎。此外，11 例孕妇分别与宫内感染（9/11，81.2%）和尿路感染（1/11，9.1%）相关。除 1 例外，所有其他 SGSP 分离株均通过 BD Phoenix 自动化系统正确识别。我们发现所有 SGSP 分离株对青霉素、氨苄西林、头孢噻肟、美罗培南和万古霉素的表型均敏感。40 株（40/45，88.9%）对红霉素和克林霉素均耐药，属于 cMLS 表型，其中大多数携带 erm(B)基因（39/40，97.5%）。虽然 cMLS/erm(B)构成所有红霉素耐药 cMLS 分离株中最常见的表型/基因型组合（25/40，62.5%），但在 7、4 和 3 株分离株中分别检测到 erm(B)/erm(A)、erm(B)/mef(A/E)和 erm(B)/erm(T)。此外，43 株（43/45，95.6%）对四环素耐药，其中 39 株（39/45，86.7%）携带 tet(L)，27 株（27/45，60.0%）携带 tet(O)，7 株（7/45，15.6%）携带 tet(M)，单独或联合携带。所有红霉素耐药分离株也对四环素耐药。
研究并引起对 SGSP 的关注很重要，SGSP 是一种被低估的机会性病原体，主要针对免疫功能低下的人群，特别是老年人、孕妇和新生儿。
