EVALUATION OF BLOOD CULTURE MEDIA FOR ISOLATION OF PYRIDOXAL-DEPENDENT STREPTOCOCCUS-MITIOR (MITIS)
EVALUATION OF BLOOD CULTURE MEDIA FOR ISOLATION OF PYRIDOXAL-DEPENDENT STREPTOCOCCUS-MITIOR (MITIS)
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DOI：
10.1128/jcm.14.3.266-272.1981
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发表时间：
1981-01-01
影响因子：
9.4
通讯作者：
ROBERTS, RB
中科院分区：
文献类型：
--
作者：
GROSS, KC;HOUGHTON, MP;ROBERTS, RB
被鉴定为吡哆醛依赖性缓症链球菌（缓症链球菌）的营养变体链球菌占链球菌性心内膜炎的5%至6%，并且可能是“培养阴性”心内膜炎的原因。因此，将三种变异菌株在11种商业血培养肉汤中的生长与在新鲜心脏输液肉汤中的生长进行比较。为了模拟临床标本，向培养瓶中注入5 ml人血，每瓶接种约500个菌落形成单位（CFU），并使用革兰氏染色和活菌计数监测7天。仅硫醇肉汤（Difco Laboratories，Detroit，Mich.）在这种低接种量下，支持无血生长。在含有血液的培养基中，在孵育2天内达到10（9）CFU/ml的最大生长，并且仅在心脏输注肉汤、硫醇肉汤和补充有盐酸吡哆醛的培养基中一致地观察到重度浑浊。哥伦比亚肉汤（BBL Microbiology Systems，科基斯维尔，马里兰州）半胱氨酸增加的巯基乙酸盐肉汤和一种脑心浸液肉汤产生中度生长（1 × 10（8）至5 × 10（8）CFU/ml），而哥伦比亚肉汤、另一种脑心浸液肉汤和两种品牌的胰蛋白酶大豆肉汤显示出适度生长（1 × 10（7）至4 × 10（7）CFU/ml）。在其他三种品牌的胰蛋白酶大豆肉汤中观察到的生长不良（1 × 10（6）至3 × 10（6）CFU/ml）通常在肉眼或革兰氏染色中不明显。此外，在接种50 CFU的胰蛋白酶大豆肉汤培养物中，40%发生生长。因此，为了确保从临床血培养物中分离这些变异链球菌，应使用含有硫醇化合物或补充有吡哆醛的培养基。应在孵育后2天内，在富含吡哆醛或含有葡萄球菌属菌株条纹的血琼脂上进行传代培养。
Nutritional variant streptococci identified as pyridoxal-dependent Streptococcus mitior (mitis) account for 5 to 6% of streptococcal endocarditis and may be a cause of "culture-negative" endocarditis. Hence, growth of three variant strains in 11 commercial blood culture broths was compared to that in fresh heart infusion broth. For simulation of clinical specimens, culture bottles were injected with 5 ml of human blood, inoculated with approximately 500 colony-forming units (CFU) per bottle, and monitored for 7 days with Gram stains and viable counts. Only Thiol broth (Difco Laboratories, Detroit, Mich.) supported growth without blood at this low inoculum. In media containing blood, maximal growth of 10(9) CFU/ml was reached within 2 days of incubation, and heavy turbidity was consistently observed in only heart infusion broth, Thiol broth, and media supplemented with pyridoxal hydrochloride. Columbia broth (BBL Microbiology Systems, Cockeysville, Md.) with increased cysteine, thioglycollate broth, and one brain heart infusion broth produced moderate growth (1 x 10(8) to 5 x 10(8) CFU/ml), whereas Columbia broth, another brain heart infusion broth, and two brands of tryptic soy broth showed fair growth (1 x 10(7) to 4 x 10(7) CFU/ml). The poor growth (1 x 10(6) to 3 x 10(6) CFU/ml) observed in three other brands of tryptic soy broth was often not apparent macroscopically or by Gram stain. Furthermore, on growth occurred in 40% of tryptic soy broth cultures inoculated with 50 CFU. Therefore, to ensure isolation of these variant streptococci from clinical blood cultures, a medium containing thiol compounds or supplemented with pyridoxal should be used. Subcultures should be made within 2 days of incubation to blood agar enriched with pyridoxal or containing a Staphylococcus sp. streak for satellitism.