Taha Mariam, Kohnen Carissa, Mallya Shruti, Kou Yuntong, Zapata Adriana, Ramirez-Arcos Sandra
Canadian Blood Services, Ottawa, ON, Canada.
J Med Microbiol. 2018 Feb;67(2):190-197. doi: 10.1099/jmm.0.000673.
Staphylococcus epidermidis is the predominant contaminant of platelet concentrates (PCs), a blood product used to treat patients with platelet deficiencies. This microorganism is able to form surface-attached aggregates (biofilms) in human skin. Herein, the abundance of S. epidermidis biofilm-producers in contaminated PCs compared to skin isolates was explored. Furthermore, the potential positive selection of S. epidermidis biofilm-producers during the blood donation process and PC manufacturing was investigated.
Twenty-four S. epidermidis isolates obtained from contaminated PCs and 48 S. epidermidis isolates obtained from the venipuncture area of human volunteers were compared for their ability to form biofilms in laboratory media and in PCs using a semi quantitative crystal violet assay. Also, the presence of the biofilm-associated icaA and icaD genes was assessed by PCR-amplification.Results/Key findings.Biofilm production in laboratory media showed a higher number of S. epidermidis biofilm-producers in the skin-derived group (43.7 %) compared to the PC-derived isolates (25 %). However, all skin and PC isolates formed biofilms in PCs. The prevalence of ica-positive biofilm-producer isolates was similar in PC and skin isolates (16.6 and 18.8 %, respectively). In contrast, the abundance of ica-negative biofilm-producers was lower in PC isolates compared to skin isolates (8.3 vs 25 %, respectively).
Positive selection of S. epidermidis biofilm-producers during blood donation and PC manufacturing was not observed. Interestingly, ica-negative biofilm-producers seem to be negatively affected by skin disinfection, blood processing and PC storage. Furthermore, this study shows that S. epidermidis adopts a biofilm-forming phenotype in PCs regardless of its genetic background or origin.
表皮葡萄球菌是血小板浓缩物（PCs）的主要污染物，血小板浓缩物是用于治疗血小板缺乏症患者的血液制品。这种微生物能够在人体皮肤中形成表面附着的聚集体（生物膜）。在此，探讨了与皮肤分离株相比，受污染的血小板浓缩物中表皮葡萄球菌生物膜产生菌的丰度。此外，还研究了表皮葡萄球菌生物膜产生菌在献血过程和血小板浓缩物制备过程中可能的阳性选择情况。
比较了从受污染的血小板浓缩物中获得的24株表皮葡萄球菌分离株和从人类志愿者静脉穿刺部位获得的48株表皮葡萄球菌分离株在实验室培养基和血小板浓缩物中形成生物膜的能力，采用半定量结晶紫测定法。此外，通过PCR扩增评估生物膜相关的icaA和icaD基因的存在情况。结果/主要发现：在实验室培养基中，与源自血小板浓缩物的分离株（25%）相比，源自皮肤的分离株中表皮葡萄球菌生物膜产生菌的数量更多（43.7%）。然而，所有皮肤和血小板浓缩物分离株在血小板浓缩物中均形成了生物膜。ica阳性生物膜产生菌分离株在血小板浓缩物和皮肤分离株中的流行率相似（分别为16.6%和18.8%）。相比之下，ica阴性生物膜产生菌在血小板浓缩物分离株中的丰度低于皮肤分离株（分别为8.3%和25%）。
未观察到表皮葡萄球菌生物膜产生菌在献血和血小板浓缩物制备过程中的阳性选择。有趣的是，ica阴性生物膜产生菌似乎受到皮肤消毒、血液处理和血小板浓缩物储存的负面影响。此外，本研究表明，无论其遗传背景或来源如何，表皮葡萄球菌在血小板浓缩物中均采用形成生物膜的表型。
