Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Antimicrob Agents Chemother. 2012 Apr;56(4):1870-6. doi: 10.1128/AAC.05650-11. Epub 2012 Jan 30.
We investigated the clinical and microbiologic features of 300 cases of cephalosporin-resistant Escherichia coli producing extended-spectrum β-lactamase (ESBL) or plasmid-mediated AmpC β-lactamase (pAmpC) at three medical centers in the United States. Solid-organ malignancy, connective tissue disease, and a recent history of surgery were more common among pAmpC-producing cases (n = 49), whereas urinary catheter at enrollment, diabetes, and hospitalization in the past year were more common among ESBL-producing cases (n = 233). The factors independently associated with clinical outcome were the following: the presence of cardiovascular disease (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.29 to 6.43), intra-abdominal infection (OR, 6.35; 95% CI, 1.51 to 26.7), other or multiples sources of infection (OR, 8.12; 95% CI, 2.3 to 28.6), age of 65 years or greater (OR, 0.43; 95% CI, 0.2 to 0.95), favorable baseline health status (OR, 0.39; 95% CI, 0.16 to 0.95), and appropriate empirical antimicrobial therapy given in the first 72 h (OR, 0.42; 95% CI, 0.20 to 0.88). β-Lactamase genes responsible for cephalosporin resistance were identified in 291 cases. CTX-M-type ESBLs accounted for 72.0%. Of those, 88.0% were CTX-M-15. The next most common type was CMY-type pAmpC (16.7%), followed by SHV- and TEM-type ESBLs (6.3 and 1.3%, respectively). Seven cases (2.3%) had KPC-type β-lactamase. Ertapenem, imipenem, meropenem, doripenem, piperacillin-tazobactam, amikacin, nitrofurantoin, and tigecycline were highly active, with greater than 90% of the isolates being susceptible. Cefepime was less active, with only 74.2% being susceptible due to the predominance of CTX-M-15. These findings have implications in the selection of appropriate empirical therapy when infection due to cephalosporin-resistant E. coli is suspected.
我们在美国的三家医疗中心调查了 300 例产生超广谱β-内酰胺酶（ESBL）或质粒介导的 AmpC β-内酰胺酶（pAmpC）的头孢菌素耐药大肠埃希菌的临床和微生物学特征。产 pAmpC 的病例（n=49）中更常见的是实体器官恶性肿瘤、结缔组织疾病和近期手术史，而产 ESBL 的病例（n=233）中更常见的是导尿管留置、糖尿病和过去一年住院。与临床结局独立相关的因素如下：心血管疾病（比值比[OR]，2.88；95%置信区间[CI]，1.29 至 6.43）、腹腔内感染（OR，6.35；95%CI，1.51 至 26.7）、其他或多种感染源（OR，8.12；95%CI，2.3 至 28.6）、年龄 65 岁或以上（OR，0.43；95%CI，0.20 至 0.95）、基线健康状况良好（OR，0.39；95%CI，0.16 至 0.95）和在最初 72 小时内给予适当的经验性抗菌治疗（OR，0.42；95%CI，0.20 至 0.88）。在 291 例中鉴定出与头孢菌素耐药相关的β-内酰胺酶基因。CTX-M 型 ESBL 占 72.0%。其中，88.0%为 CTX-M-15。下一个最常见的类型是 CMY 型 pAmpC（16.7%），其次是 SHV 和 TEM 型 ESBL（分别为 6.3%和 1.3%）。7 例（2.3%）有 KPC 型β-内酰胺酶。厄他培南、亚胺培南、美罗培南、多尼培南、哌拉西林他唑巴坦、阿米卡星、呋喃妥因和替加环素高度活跃，超过 90%的分离物敏感。头孢吡肟的活性较低，由于 CTX-M-15 的优势，只有 74.2%的分离物敏感。这些发现对怀疑头孢菌素耐药大肠埃希菌感染时选择合适的经验性治疗具有重要意义。
