國內碳青黴烯類抗藥性腸桿菌的基因型變異及群突發

Genotype Variation and Hospital Outbreak of Carbapenem Resistant Enterobacteriaceae (CRE) in Taiwan

李聰明(Chun-Ming Lee)

指導教授 ： 李孟智

中山醫學大學/醫學院/醫學研究所/博士(2013年)

https://doi.org/10.6834/CSMU.2013.00192

摘要

研究目的：對於廣效性的抗生素產生抗藥性如廣效性β－內醯胺酶 (Extended Spectrum β-lactamases -ESBL)在腸內桿菌已經是廣為周知的事，在這種情形下碳青黴烯類抗生素(Carbapenems)是治療這些抗藥性腸內桿菌很重要的抗生素。臨床上，碳青黴烯類抗藥性的腸桿菌(carbapenems resistant Eenterobacteriaceae -CRE)的產生在以往並不常見，直到最近這幾年在美國陸續地被報告而且在腸內桿菌的感染中CRE的流行率也逐漸地增加.這個研究是探討目前台灣CRE的流行病學基因的變異情況，臨床的狀況和可能的群聚或群突發感染。

研究方法及資料：從2011年6月到9月總共有305株CRE對ertapenem 非敏感的腸內桿菌(即最小抑菌濃度大於等於1微克/毫升，≧1μg/ml)收集自全臺灣不同地區的11家醫院。這些菌株在實驗室以肉湯稀釋法對12種不同抗菌藥物做最小抑菌濃度(MIC)的測量，同時也使用聚合酶鏈反應(PCR)來偵測是否帶有碳青黴烯類酶(carbapenemase)的基因存在。最後再以脈衝電泳法(pulsed-field gel electrophoresis-PFGE)及多位基因序列分析法(multilocus sequence typing-MLST)來對分離出來的碳青黴烯類酶作基因型的分析。

研究結果：所收集到的ertapenem非敏感型的腸內桿菌包括有克雷伯氏桿菌(Klebsiellae pneumoniae-KP) 219株，大腸桿菌(Escherichia.coli-E.Coli) 64株、陰溝腸桿菌(Enterobacter cloacae) 15株及其他腸內桿菌7株。在這些ertapenem非敏感的腸內桿菌有7株(2.3%)對多粘菌素(colistin)的最小抑菌濃度大於4微克/毫升(≧4ｕg/ml)，而有24株(7.9%)對替加環素(tigecycline)不具有敏感性，即最小抑菌濃度大於2微克/毫升(≧2ｕg/ml)。總共有30株(9.8%)具有碳青黴烯類酶，其中16株(7.3%)是屬於帶有克雷伯氏碳青黴烯類酶-2 (Klebsiella pneumoniae carbapenemase-2即KPC-2)的肺炎克雷伯氏菌(即所謂KPC-2-KP)，此外也有5株(2.3%)是帶有亞胺培南-8(IMP-8) 的肺炎克雷伯氏菌。其他具有碳青黴烯類酶IMP-8在陰溝腸桿菌中有5株(33.3%),另外在大腸桿菌(E-coli)有1株，產酸克雷伯氏菌(Klebsiellae oxytoca)有1株及弗羅因德氏橡酸菌(Citrobacter freundii)有1株。此外有1株E. coli 同時帶有OXA-23-like 和 OXA-51-like基因。在這16株帶有KPC-2-KP都來自臺灣北部4家不同的醫院。所有這16株KPC-2-KP均對丁胺卡那黴素(amikacin)和多粘菌素(colistin)具有敏感性而且也有相同的基因型(即pulsotype 1)以及相同的序列型別(即sequence type 11) 。有KPC-2-KP感染的病人主要來自加護病房的嚴重病人(共有14個病人佔88%)，其中有4個病人在感染KPC-2-KP後的14天內死亡。

結論與建議：此研究是臺灣首次證實有本土性KPC-2-KP的存在，而且已經在醫院內及醫院間發生群突發的第一手研究報告。在這次多中心CRE的基因型變異流行病學調查中，我們首次發現了北臺灣有醫院內以及醫院之間 KPC-2-KP 群突發現象。雖然在中台灣和南台灣只有4家醫院參與而且也並沒有出現KPC的抗藥基因，但這並不代表這些區域都沒有帶有KPC的腸桿菌；因此進一步的全國性KPC-KP流行病學調查是有其必要性的，而且醫院應該更加強和落實感染管制措施以避免全國性的散播。

關鍵字

碳青黴烯類抗藥性的腸桿菌 ； 克雷伯氏碳青黴烯類酶-2 ； 克雷伯氏桿菌 ； 碳青黴烯類酶基因序列型別11 群突發 ； 臺灣

並列摘要

Objectives: All carbapenems (ertapenem, imipenem, meropenem, and doripenem) were highly active against Enterobacteriaceae isolates before. Recently, carbapenem-resistant Enterobacteriaceae (CRE) isolates emerged rapidly in many countries and resulted in intra-continental and inter-continental spreads. This study was to investigate the epidemiology of CRE in ertapenem-non-susceptible Enterobacteriaceae (ENSE) isolates (minimum inhibitory concentrations of ertapenem ≧ 1 μg/ml) in Taiwan.
Methods: From June to September in 2011, 305
ertapenem-non-susceptible Enterobacteriaceae (ENSE) isolates (minimum inhibitory concentrations of ertapenem ≧ 1 mg/L) were collected from 11 hospitals in different parts of Taiwan. MICs of these isolates were determined and genes for carbapenemases were detected using PCR. Genotypes of isolates possessing carbapenemase genes were identified by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing.
Results: These 305 ENSE isolates included Klebsiella pneumoniae (n=219), Escherichia coli (n=64), Enterobacter cloacae (n=15) and other species (n=7). Seven (2.3%) of ENSE isolates exhibited colistin MICs of >4 mg/L and 24 (7.9%) were not susceptible to tigecycline (MIC of >2 mg/L). Genes encoding carbapenemases was positive in 30 (9.8%) isolates: K. pneumoniae carbapenemase-2 (KPC-2) in 16 (7.3%) in K pneumoniae (KPC-2-KP), and IMP-8 in five (2.3%) K. pneumoniae, five (33.3%) E. cloacae, and in one each in E. coli, K. oxytoca and Citrobacter freundii isolates. One E. coli isolate possessed both OXA-23-like and OXA-51-like genes. The 16 KPC-2-KP isolates were isolated from patients hospitalized at four hospitals in northern Taiwan: Hospitals A (n=2), B (n=6), C (n=7), and D (n=1). All the 16 KPC-2-KP isolates were susceptible to amikacin and colistin and had similar pulsotype (PT-1) (≧80% similarity) and same sequence type (ST11). Similar PTs were also found in four K. pneumoniae (PT-2 in two isolates from Hospital H and PT-3 in two isolates from Hospital A) and E. cloacae isolates (PT-6 in two isolates from Hospital K) harboring IMP-8. The acquisitions of KPC-2-KP mostly occurred in severely-ill patients admitted at the intensive care unit (n=14, 88%). Four patients with KPC-2-KP isolation died within 14 days of hospitalization.
Conclusions: In this multi-center surveillance study, we identified the fist outbreak of intra-hospital and inter-hospital dissemination of KPC-2-KP in northern Taiwan .Although only four hospitals from central and southern Taiwan were included in this study, the fact that no KPC-bearing isolates were identified in these regions does not mean that these regions must be clear of KPC-bearing isolates. Further nationwide surveillance of KPC-KP is necessary, and strict infection control should be enforced.

並列關鍵字

carbapenem resistant Eenterobacteriaceae (CRE) ； Klebsiella pneumoniae carbapenemase-2 ； Klebsiella pneumoniae ； carbapenem resistance ； sequence type 11 ； outbreak ； Taiwan

參考文獻

1. Jacoby GA, Munoz-Price LS. The new beta-lactamases. N Engl J Med 2005; 352:380–91.

2. Hidron AI, Edwards JR, Patel J, et al. NHSN annual update: Antimicrobialresistant

pathogens associated with healthcare-associated infections:Annual summary of data reported to the National Healthcare SafetyNetwork at the Centers for Disease Control and Prevention, 2006–2007.Infect Control Hosp Epidemiol 2008; 29:996–1011.

3. Bratu S, Landman D, Haag R, et al. Rapid spread of carbapenemresistant Klebsiella pneumoniae in New York City: A new threat to our antibiotic armamentarium. Arch Intern Med 2005; 165:1430–5.

4. Patel G, Huprikar S, Factor SH, Jenkins SG, Calfee DP. Outcomes of carbapenem- resistant Klebsiella pneumoniae infection and the impact of antimicrobial and adjunctive therapies. Infect Control Hosp Epidemiol 2008; 29:1099–106.