McGowan John E
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, USA.
Am J Med. 2006 Jun;119(6 Suppl 1):S29-36; discussion S62-70. doi: 10.1016/j.amjmed.2006.03.014.
Nonfermenting gram-negative bacteria pose a particular difficulty for the healthcare community because they represent the problem of multidrug resistance to the maximum. Important members of the group in the United States include Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and Burkholderia cepacia. These organisms are niche pathogens that primarily cause opportunistic healthcare-associated infections in patients who are critically ill or immunocompromised. Multidrug resistance is common and increasing among gram-negative nonfermenters, and a number of strains have now been identified that exhibit resistance to essentially all commonly used antibiotics, including antipseudomonal penicillins and cephalosporins, aminoglycosides, tetracyclines, fluoroquinolones, trimethoprim-sulfamethoxazole, and carbapenems. Polymyxins are the remaining antibiotic drug class with fairly consistent activity against multidrug-resistant strains of P aeruginosa, Acinetobacter spp, and S maltophilia. However, most multidrug-resistant B cepacia are not susceptible to polymyxins, and systemic polymyxins carry the risk of nephrotoxicity for all patients treated with these agents, the elderly in particular. A variety of resistance mechanisms have been identified in P aeruginosa and other gram-negative nonfermenters, including enzyme production, overexpression of efflux pumps, porin deficiencies, and target-site alterations. Multiple resistance genes frequently coexist in the same organism. Multidrug resistance in gram-negative nonfermenters makes treatment of infections caused by these pathogens both difficult and expensive. Improved methods for susceptibility testing are needed when dealing with these organisms, including emerging strains expressing metallo-beta-lactamases. Improved antibiotic stewardship and infection-control measures will be needed to prevent or slow the emergence and spread of multidrug-resistant, nonfermenting gram-negative bacilli in the healthcare setting.
非发酵革兰氏阴性菌给医疗界带来了特殊困难，因为它们最大程度地体现了多重耐药性问题。在美国，该菌群的重要成员包括铜绿假单胞菌、鲍曼不动杆菌、嗜麦芽窄食单胞菌和洋葱伯克霍尔德菌。这些微生物是特定病原体，主要在重症或免疫功能低下的患者中引起机会性医疗相关感染。多重耐药性在革兰氏阴性非发酵菌中很常见且呈上升趋势，目前已鉴定出一些菌株对几乎所有常用抗生素均有耐药性，包括抗假单胞菌青霉素和头孢菌素、氨基糖苷类、四环素类、氟喹诺酮类、甲氧苄啶 - 磺胺甲恶唑和碳青霉烯类。多粘菌素是对铜绿假单胞菌、不动杆菌属和嗜麦芽窄食单胞菌的多重耐药菌株仍具有相当一致活性的剩余抗生素类别。然而，大多数多重耐药的洋葱伯克霍尔德菌对多粘菌素不敏感，并且全身性多粘菌素对所有使用这些药物治疗的患者，尤其是老年人，都有肾毒性风险。在铜绿假单胞菌和其他革兰氏阴性非发酵菌中已鉴定出多种耐药机制，包括酶的产生、外排泵的过度表达、孔蛋白缺陷和靶位点改变。多个耐药基因经常共存于同一生物体中。革兰氏阴性非发酵菌中的多重耐药性使得治疗由这些病原体引起的感染既困难又昂贵。在处理这些微生物时，包括对表达金属β - 内酰胺酶的新出现菌株，需要改进药敏试验方法。需要改进抗生素管理和感染控制措施，以预防或减缓医疗环境中多重耐药、非发酵革兰氏阴性杆菌的出现和传播。
