Hill R L, Casewell M W
Dulwich Public Health Laboratory and Medical Microbiology, Guy's, King's and St Thomas' School of Medicine, King's Denmark Hill Campus, Bessemer Road, London, UK.
J Hosp Infect. 2000 Jul;45(3):198-205. doi: 10.1053/jhin.2000.0733.
Due to the emergence of mupirocin-resistance in some epidemic strains of methicillin resistant Staphylococcus aureus (EMRSA) and the appearance of EMRSA with intermediate resistance to vancomycin, we evaluated the in-vitro activity of 5% povidone-iodine ('Betadine') cream as a possiblealternative to mupirocin for the elimination of nasal carriage of S. aureus. As judged by enrichment culture, povidone-iodine was bactericidal against three mupirocin-sensitive strains of S. aureus from nasal carriers, and against mupirocin-resistant and -sensitive strains of EMRSA types 3, 15 and 16, after incubation with povidone-iodine for 1.0 min at 32 degrees C. Mupirocin nasal ointment did not prevent growth after 180 min incubation. In a quantitative suspension test, 1:100 dilution of povidone-iodine cream completely eliminated an inoculum of 10(8)cfu/mL of all nine test organisms after incubation at 32 degrees C for 1.0 min, and 1:1000 dilution reduced cfu, by a factor of 10(5). After direct inoculation of the povidone-iodine cream to give 10(5)cfu/g, none of the test strains were recoverable after 30 s, giving a killing rate of approximately 10(4)cfu/s; for mupirocin nasal ointment, the maximum reduction of mupirocin-sensitive strains was ten fold after 3 h. Povidone-iodine activity was not detectable in sensitivity-testing agar, although 0.025% of povidone-iodine was detectable in a 15% nutrient strength tryptone soya agar. Using this minimal medium, the addition of nasal secretions (from any of 11 samples) reduced the activity of povidone-iodine by 80-90%, but mupirocin activity was unaffected. One millilitre of nasal secretions inactivated the equivalent of approximately 22.5 mg of povidone-iodine. These results suggest that povidone-iodine cream may have a role in the prevention of colonization and infection caused by MRSA, including mupirocin-resistant strains.
由于某些耐甲氧西林金黄色葡萄球菌（EMRSA）流行菌株中出现了对莫匹罗星的耐药性，以及出现了对万古霉素具有中度耐药性的EMRSA，我们评估了5%聚维酮碘（“碘伏”）乳膏作为莫匹罗星的一种可能替代物用于消除金黄色葡萄球菌鼻腔携带的体外活性。通过富集培养判断，在32℃下用聚维酮碘孵育1.0分钟后，聚维酮碘对来自鼻腔携带者的三株对莫匹罗星敏感的金黄色葡萄球菌菌株以及对3型、15型和16型EMRSA的耐莫匹罗星和敏感菌株具有杀菌作用。莫匹罗星鼻软膏在孵育180分钟后不能阻止生长。在定量悬液试验中，聚维酮碘乳膏1:100稀释液在32℃下孵育1.0分钟后完全消除了所有九种受试微生物10(8)cfu/mL的接种物，1:1000稀释液使cfu减少了10(5)倍。将聚维酮碘乳膏直接接种至10(5)cfu/g后，30秒后所有受试菌株均无法检出，杀灭率约为10(4)cfu/秒；对于莫匹罗星鼻软膏，对莫匹罗星敏感的菌株在3小时后最大减少量为10倍。在敏感性试验琼脂中未检测到聚维酮碘活性，尽管在15%营养强度的胰蛋白胨大豆琼脂中可检测到0.025%的聚维酮碘。使用这种基础培养基，添加鼻腔分泌物（来自11个样本中的任何一个）使聚维酮碘的活性降低了80 - 90%，但莫匹罗星的活性未受影响。1毫升鼻腔分泌物使相当于约22.5毫克的聚维酮碘失活。这些结果表明，聚维酮碘乳膏可能在预防由耐甲氧西林金黄色葡萄球菌（包括耐莫匹罗星菌株）引起的定植和感染中发挥作用。
