Sundaram S, Eisenhuth J, Howard G, Brandwein H
Pall Corporation, Scientific and Laboratory Services Department, Port Washington, NY, USA.
PDA J Pharm Sci Technol. 2001 Mar-Apr;55(2):65-86.
The results of bacterial challenge tests conducted on several 0.2 and 0.22 micron rated "sterilizing grade" filter cartridge types with bacteria from a natural water source are presented. Eight different 0.2/0.22 micron rated "sterilizing grade" filter types from four different filter manufacturers, claimed to be capable of retaining Brevundimonas diminuta at a challenge level of 10(7) CFU/cm2, were tested. The filters tested included nylon 6.6 and polyamide filters from two manufacturers, modified or hydrophilic PVDF filters from two manufacturers, modified or asymmetric PES filters from three manufacturers, and cellulose acetate filters from a single manufacturer. Consistent bacterial penetration was observed, over the 18-24 h challenge period, for all twenty-five integral 0.2 and 0.22 micron rated filter cartridges tested, at challenge levels of about 10(1)-10(4) CFU/cm2, indicating that natural waterborne bacteria were more penetrative than B. diminuta. The observed penetration was thus qualitatively independent of filter media type or manufacturer. These results add to the growing body of evidence that shows 0.2 and 0.22 micron rated filters may not remove all microorganisms under all conditions. These results further establish that bacterial penetration of 0.2/0.22 micron rated filters is not limited just to (1) specific membrane types, or (2) extended duration challenges (>> 24 h), or (3) extremely high challenge levels, or (4) bacteria that can only exist in a penetrative state in an artificial laboratory setting.
本文展示了对几种额定孔径为0.2和0.22微米的“除菌级”滤芯进行细菌挑战测试的结果，挑战细菌来自天然水源。测试了来自四个不同过滤器制造商的八种不同额定孔径为0.2/0.22微米的“除菌级”过滤器类型，这些过滤器据称能够在10(7) CFU/cm2的挑战水平下截留缺陷短波单胞菌。所测试的过滤器包括来自两个制造商的尼龙6.6和聚酰胺过滤器、来自两个制造商的改性或亲水性聚偏氟乙烯过滤器、来自三个制造商的改性或不对称聚醚砜过滤器以及来自一个制造商的醋酸纤维素过滤器。在18 - 24小时的挑战期内，对所有测试的25个完整的额定孔径为0.2和0.22微米的滤芯，在约10(1)-10(4) CFU/cm2的挑战水平下均观察到持续的细菌穿透，这表明天然水源中的细菌比缺陷短波单胞菌更具穿透性。因此，观察到的穿透在质量上与过滤介质类型或制造商无关。这些结果进一步证明了越来越多的证据表明，额定孔径为0.2和0.22微米的过滤器可能无法在所有条件下去除所有微生物。这些结果还进一步表明，额定孔径为0.2/0.22微米的过滤器的细菌穿透不仅限于(1)特定的膜类型，或(2)延长的挑战持续时间(>> 24小时)，或(3)极高的挑战水平，或(四)只能在人工实验室环境中以穿透状态存在的细菌。
