O'Fallon Erin, Pop-Vicas Aurora, D'Agata Erika
Department of Medicine, Hebrew Rehabilitation Center for Aged, Boston, MA 02131, USA.
J Gerontol A Biol Sci Med Sci. 2009 Jan;64(1):138-41. doi: 10.1093/gerona/gln020. Epub 2009 Jan 20.
Infections caused by antimicrobial-resistant bacteria are associated with substantial morbidity and mortality. Residents of long-term care facilities (LTCF) are among the main reservoirs of antimicrobial-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Multidrug-resistant gram-negative organisms (MDRGN) are emerging as important pathogens among LTCF residents. Data on the clinical epidemiology of MDRGN, especially in comparison to VRE and MRSA, are limited.
All clinical cultures collected from residents of a 750-bed LTCF for a period of 2 years were analyzed for the presence of MDRGN, VRE, and MRSA. Multidrug resistance among gram-negative bacteria was defined as resistance to three or more antimicrobials or antimicrobial groups including extended-spectrum penicillins (ampicillin/sulbactam or piperacillin/tazobactam), cephalosporins (cefazolin or ceftriaxone), gentamicin, ciprofloxacin, and trimethoprim-sulfamethoxazole (TMP/SMX).
A total of 1,661 clinical cultures were included in the analysis. MDRGN were recovered from 180 (10.8%) cultures, MRSA from 104 (6.3%), and VRE from 11 (0.6%). MDRGN were isolated more frequently than MRSA or VRE throughout the study period. The prevalence of MDRGN increased significantly from 7% in 2003 to 13% in 2005 (p = .001). More than 80% of MDRGN isolates were resistant to ciprofloxacin, TMP/SMX, and ampicillin/sulbactam. Resistance to three, four, and five or more antimicrobials were identified among 122 (67.8%), 47 (26.1%), and 11 (6.1%) MDRGN isolates, respectively.
Rates of MDRGN exceeded those of MRSA and VRE and increased throughout the study period. Resistance to multiple, commonly prescribed antimicrobials among MDRGN raises concerns about therapeutic options available to treat MDRGN infections among LTCF residents.
耐抗菌药物细菌引起的感染与大量发病和死亡相关。长期护理机构（LTCF）的居民是耐抗菌药物细菌的主要储存宿主之一，包括耐甲氧西林金黄色葡萄球菌（MRSA）和耐万古霉素肠球菌（VRE）。多重耐药革兰氏阴性菌（MDRGN）正在成为LTCF居民中的重要病原体。关于MDRGN临床流行病学的数据，尤其是与VRE和MRSA相比的数据有限。
对一家拥有750张床位的LTCF居民在2年期间采集的所有临床培养物进行分析，以检测MDRGN、VRE和MRSA的存在情况。革兰氏阴性菌中的多重耐药定义为对三种或更多种抗菌药物或抗菌药物类别耐药，包括广谱青霉素（氨苄西林/舒巴坦或哌拉西林/他唑巴坦）、头孢菌素（头孢唑林或头孢曲松）、庆大霉素、环丙沙星和甲氧苄啶-磺胺甲恶唑（TMP/SMX）。
分析共纳入1661份临床培养物。从180份（10.8%）培养物中分离出MDRGN，从104份（6.3%）中分离出MRSA，从11份（0.6%）中分离出VRE。在整个研究期间，MDRGN的分离频率高于MRSA或VRE。MDRGN的患病率从2003年的7%显著增加到2005年的13%（p = .001）。超过80%的MDRGN分离株对环丙沙星、TMP/SMX和氨苄西林/舒巴坦耐药。在122份（67.8%）、47份（26.1%）和11份（6.1%）MDRGN分离株中分别鉴定出对三种、四种以及五种或更多种抗菌药物耐药。
MDRGN的发生率超过MRSA和VRE，且在整个研究期间有所增加。MDRGN对多种常用抗菌药物耐药，这引发了对治疗LTCF居民中MDRGN感染可用治疗方案的担忧。
