抗多药性细菌引起新的忧虑

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抗多药性细菌引起新的忧虑

mgl206

健康人生，从心开始
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2008-01-23 19:30

New Worries About Multidrug-Resistant Bacteria
Community prevalence of multidrug-resistant strains of pneumococci, and of invasive community-based methicillin-resistant Staphylococcus aureus, is increasing.

Two studies raise concerns about the increased prevalence of multidrug-resistant bacteria in community-based settings. The first study consisted of population-based surveillance of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in nine U.S. communities in 2005, with "invasive" defined as isolation of MRSA from a normally sterile body site (e.g., blood, spinal fluid, bone). The 8987 cases were categorized as healthcare-associated with community onset (e.g., presence of invasive device at hospital admission, or a hospitalization, surgery, or residence in a long-term care facility in the previous 12 months), healthcare-associated with hospital onset, or community-associated. The proportions of cases in these three categories were 58%, 27%, and 14%, respectively. The overall incidence rate was 31.8 per 100,000, and the standardized mortality rate was 6.3 per 100,000. The authors estimate that these rates translate to roughly 94,000 invasive MRSA cases in the U.S., with roughly 19,000 deaths.

In the second study, tympanocentesis was performed in 212 children with either first or second episodes of acute otitis media (AOM) or AOM with treatment failure. Of the 212 samples, bacterial pathogens were found in 162, including 94 with Haemophilus influenzae and 59 with Streptococcus pneumoniae. The proportion of pneumococcal isolates not covered by the 7-valent pneumococcal vaccine increased from 2003?C2004 (12/28; 43%) to 2005?C2006 (14/19; 74%). Among these isolates, the prevalence of multidrug-resistance also increased during this period; although five of nine multidrug resistant infections responded to levofloxacin (the others to tympanostomy tube insertion), the authors argue vigorously for not making the fluoroquinolones the standard antibiotic choice for AOM, citing safety concerns and risk for further resistance.

Comment: Together, these results describe a major and increasingly prevalent problem of bacterial resistance that is not confined to acute medical care settings. Most of the invasive MRSA cases originated outside the hospital, many in people without prior healthcare exposure. The number of cases of AOM with multidrug-resistant pneumococci not covered by the pneumococcal vaccine is small but growing and would be quite ominous if found to be representative of larger populations. An editorialist notes that the estimated number of U.S. deaths from MRSA infection exceeds that attributable to HIV/AIDS in 2005 and calls for expanded and more intense surveillance and infection-control programs.

— Thomas L. Schwenk, MD

Published in Journal Watch General Medicine October 23, 2007

Citation:
Klevens RM et al. Invasive methicillin-resistant Staphylococcus aureus infections in the United States. JAMA 2007 Oct 17; 298:1763.

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mgl206

健康人生，从心开始
医博园版主

发贴: 4172
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得票: 21

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2008-01-23 19:31

对耐多药细菌的新忧虑

社区耐多药的肺炎双球菌及入侵性社区耐甲氧苯青霉素金黄色葡萄球菌的流行正呈上升趋势。
两项研究引起人们对社区医疗机构中耐多药细菌逐渐流行这一情况的关注。第一项研究是2005年在美国9 个社区医疗机构监测侵入性耐甲氧西林金黄色葡萄球菌感染情况，其中侵入性的定义是指耐甲氧苯青霉素金黄色葡萄球菌从消毒后的身体部位（如血液、脊髓液、骨）中隔绝。8987名病例分为自社区发生的护理相关性感染（如前12个月里在医院门诊、住院或手术使用的侵入性器械的存在或体内留有长期护理设施）、自医院发生的护理相关性感染或社区相关性感染，这三类感染在全部接受监测的病例中所占的比例分别为58%、27%及14%.每10万人中的发生率为31.8%，标化死亡率为6.3 /100,000人，作者估计这些比率已发生了改变，全美约有94,000例耐甲氧西林金黄色葡萄球菌感染病例，其中约19000例死亡。
第二项研究中，对212名中耳炎患儿实施鼓膜穿刺术，这此患儿既有首次发生急性中耳炎也有第二次发生急性中耳炎或急性中耳炎治疗失败的，212个样本中，162个样本检测出细菌病原体，这其中包括94个嗜血杆菌流感感染样本和59个链球菌肺炎感染样本。肺炎链球菌菌株在未经7价肺炎链球菌疫苗免疫过的儿童中的发生率由2003?C2004年的12/28、 43%上升至2005?C2006年的 14/19; 74%。在这菌株中，耐多药菌株的流行在这一时期也有所上升；尽管9名耐多药菌感染的患者中有5 名对左氧氟沙星的响应（其他患者采用造口引流术），作者在此积极讨论的不是去制造氟喹诺酮这一治疗急性中耳炎标准抗生素药物，而是要引起人们对安全的关注及细菌会进一步耐药的风险。
评论：总体而言，这些研究结果描述了一个主要的且日益普遍的细菌耐药性问题，这一问题已不只存在于急症医疗机构。大部份入侵性耐甲氧苯青霉素金黄色葡萄球菌以生自医院外部，许多患者事先并未接受过诊治。未经肺炎链球菌疫苗免疫过的儿童发生耐多药肺炎链球菌感染的病例数虽少但却有上升的趋势，如果发现这一现象代表大部份群体，这将是一不祥之兆。主笔作者指出美国2005年死于耐甲氧苯青霉素金黄色葡萄球菌感染的病例估计已超过HIV/AIDS感染的患者。作者呼吁应扩大和加强对感染控制程序的监管力度。

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