腸內菌E. coli-ESBL社區型感染的流行病學特性與治療對策

Community-onset Extended-spectrum Beta-lactamase-producing Escherichia Coli Infection: Clinical Implications and Therapeutic Strategies

造成院內感染的致病細菌中，有些因會產生廣效性乙內醯胺酶，尤其是肺炎克雷伯氏菌（Klebsiella pneumoniae），常與致病率、死亡率、住院日數、住院花費的增加是呈正相關的。然而，會產生廣效性乙內醯胺酶的大腸桿菌（ESBL-producing Escherichia coli）感染，不像那些多重抗藥性的院內感染細菌，反而較常發生在社區間。正因為這些新興崛起的抗藥性的大腸桿菌會造成常見疾病的治療成效不如預期，如泌尿道感染或菌血症，的確帶來不少臨床上的衝擊。相對於那些不帶有會產生廣效性乙內醯胺酶能力的細菌，這些抗藥性細菌感染也會造成較高的死亡率。最近的臨床觀察調查報告中，這些ESBLs腸內菌已在全世界社區中造成不少泌尿道感染。這些細菌對許多抗生素都有抗藥性，如頭孢素類、奎諾酮類、胺基醣甘類、或磺胺類抗生素，或許泌尿道感染的治療指引應該做進一步修正。最近的資料指出，這些疾病嚴重度不高的ESBL producers感染，例如社區發生的泌尿道感染，可以使用fosfomycin、nitrofurantoin、ß-lactam/ ß-lactamas inhibitor做為替代治療藥物。雖然carbapenems依然是治療這些抗藥細菌感染最有效的抗生素，我們應該小心謹慎使用它們，以避免造成更強的抗藥性細菌產生。

Nosocomial infections with extended-spectrum beta-lactamase (ESBL) producers, especially those caused by Klebsiella pneumoniae, have been associated with increased morbidity, mortality, length of hospital stay, and hospital costs. Unlike the nosocomial multidrug-resistant organisms, ESBL-producing Escherichia coli frequently spread in the community. The emergence of E. coli ESBL producers may have significant clinical implications, since it may reduce the therapeutic options for common illnesses such as urinary tract infections (UTIs) and bacteremia. ESBL-producing E. coli also cause a higher mortality rate than non-ESBL-producing isolates. Recent pilot surveillance studies have demonstrated that ESBL-producing strains are the main cause of community-onset UTIs worldwide. Because these organisms have shown a high resistance to cephalosporins, quinolones, aminoglycosides, and trimethoprim-sulfamethoxazole, the guidelines for UTI therapy should be revised. Recent data show that fosfomycin, nitrofurantoin, and β-lactam/β-lactamase inhibitors are potential alternatives for treating non-serious infections such as community-onset UTIs caused by ESBL producers. Although carbapenems were found to be the most effective antibiotics for ESBL producers, they should be used more prudently to prevent increasing selective pressure.