Division of Microbiology, Calgary Laboratory Services, Calgary, Alberta, Canada.
Curr Pharm Des. 2013;19(2):257-63.
Escherichia coli remains one of the most frequent causes of nosocomial and community-acquired bacterial infections including urinary tract infections, enteric infections, and systemic infections in humans. Extra-intestinal pathogenic E. coli or ExPEC had emerged during the 2000s as an important player in the resistance to antibiotics, especially to the cephalosporins and fluoroquinolones. Most importantly among ExPEC, is the increasing recognition of isolates producing "newer β-lactamases" that consist of plasmidmediated AmpC β-lactamases (e.g. CMY), extended-spectrum β-lactamases (e.g. CTX-M), and carbapenemases (e.g. NDM, KPC and OXA-48). Since the mid 2000's, E. coli that produce CTX-M enzymes (especially CTX-M-15), have emerged worldwide as important causes of community-associated urinary tract (UTIs) and blood stream infections. Community-associated acquisition and infections due to enterobacteria with plasmid-mediated AmpC β-lactamases are a relatively recent phenomenon and have been described in Canada and USA. Empiric antibiotic coverage for these resistant organisms should be considered in community patients presenting with sepsis involving the urinary tract especially if a patient recently traveled to a high-risk area. If this emerging public health threat is ignored, it is possible that the medical community may be forced in the near future to use the carbapenems as the first choice for the empirical treatment of serious infections associated with urinary tract infections originating from the community.
大肠杆菌仍然是医院获得性和社区获得性细菌性感染的最常见原因之一，包括尿路感染、肠道感染和人类全身感染。肠外致病性大肠杆菌或 ExPEC 在 21 世纪出现，成为对抗生素，特别是头孢菌素和氟喹诺酮类药物耐药的重要因素。在 ExPEC 中最重要的是，越来越多的分离株产生“新型β-内酰胺酶”，这些酶由质粒介导的 AmpCβ-内酰胺酶（如 CMY）、超广谱β-内酰胺酶（如 CTX-M）和碳青霉烯酶（如 NDM、KPC 和 OXA-48）组成。自 21 世纪中期以来，产生 CTX-M 酶（特别是 CTX-M-15）的大肠杆菌已在全球范围内成为社区相关性尿路感染（UTI）和血流感染的重要原因。由于肠杆菌具有质粒介导的 AmpCβ-内酰胺酶而导致的社区获得性和感染是一个相对较新的现象，在加拿大和美国已有描述。对于这些耐药菌，社区患者出现败血症合并尿路感染时，应考虑经验性抗生素治疗，特别是如果患者最近前往高危地区。如果忽视这种新出现的公共卫生威胁，在不久的将来，医学界可能被迫将碳青霉烯类药物作为治疗源自社区的尿路感染相关严重感染的首选经验性治疗药物。
