CTX-M-35 extended-spectrum beta-lactamase conferring ceftazidime resistance in Citrobacter koseri.
CTX-M-35 extended-spectrum beta-lactamase conferring ceftazidime resistance in Citrobacter koseri.
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CTX-M-35 超广谱 β-内酰胺酶赋予科塞里柠檬酸杆菌头孢他啶耐药性。
DOI：
10.1016/j.ijantimicag.2009.12.004
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发表时间：
2010
影响因子：
10.8
通讯作者：
Doi,Yohei
中科院分区：
文献类型：
--
作者：
Tian,Guo-Bao;Adams-Haduch,JenniferM;Qureshi,ZubairA;Wang,Hong-Ning;Doi,Yohei
ctx - m型扩展谱β-内酰胺酶（ESBLs）是一类在世界范围内日益普遍的扩展谱β-内酰胺酶。超过90种ctx - m型酶已注册（http://www）。lahey。Org/studies)，基于氨基酸序列同源性属于五个簇。与tem和shv型ESBLs不同，大多数ctx - m型ESBLs对头孢噻肟的底物偏好强于头孢他啶。在这里，我们报告鉴定优先水解头孢他啶的CTX-M-2变异，从美国的临床分离物中获得。患者是一名98岁的女性，因充血性心力衰竭加重而入住匹兹堡大学医学中心（Pittsburgh， PA）。自入院以来，她未接受任何抗微生物药物治疗。住院期间出现膀胱炎症状，住院第7天尿液含白细胞≥182个/高倍场。尿培养同时培养出≥105个菌落形成单位(CFU)/mL的克氏柠檬酸杆菌和大肠杆菌。经静脉滴注后口服头孢呋辛治疗6天后，患者无症状，尿中白细胞清除。头孢呋辛对大肠杆菌易感，但对克氏梭菌不敏感。重复尿培养培养出80000 CFU/mL的柯氏弧菌。这被认为代表了定植，患者没有进一步接受抗菌治疗。
CTX-M-type extended-spectrum β-lactamases (ESBLs) are a group of ESBLs that are becoming increasingly common worldwide. Over 90 CTX-M-type enzymes have been registered (http://www. lahey. org/studies), belonging to five clusters based on amino acid sequence homology. Unlike TEM-and SHV-type ESBLs, most CTX-M-type ESBLs have strong substrate preference for cefotaxime over ceftazidime. Here we report identification of a CTX-M-2 variant that preferentially hydrolyses ceftazidime, obtained from a clinical isolate in the USA.The patient was a 98-year-old female who was admitted to the University of Pittsburgh Medical Center (Pittsburgh, PA) for exacerbation of congestive heart failure. She had not received any antimicrobials since her admission. During the hospital course she developed symptoms of cystitis, and urine taken on the seventh hospital day contained≥ 182 leukocytes/high power field. Concurrent urine culture grew≥ 105 colony-forming units (CFU)/mL of Citrobacter koseri and Escherichia coli. After 6 days of treatment with intravenous and then oral cefuroxime, to which E. coli but not C. koseri was susceptible, the patient became asymptomatic and leukocytes cleared from the urine. Repeat urine culture grew 80 000 CFU/mL of C. koseri. This was felt to represent colonisation and the patient was not further treated with antimicrobial therapy.