台灣中部某醫學中心醫療照護相關之Methicillin抗藥性金黃色葡萄球菌感染率預測方法之探討－趨勢、抗生素使用量與抗藥性相關性及時間序列分析和分子生物分型

A Study of Healthcare-associated Methicillin-resistant Staphylococcus aureus Forecasting Models at a Tertiary Care Hospital in Central Taiwan- the Trends, Correlation of Antimicrobial Consumption and Resistance, Time Series Analysis, and Molecular Typing.

李原地(Yuan-Ti Lee)

指導教授 ： 李孟智

中山醫學大學/醫學院/醫學研究所/博士(2011年)

https://doi.org/10.6834/CSMU.2011.00069

摘要

研究背景：Methicillin抗藥性金黃色葡萄球菌（MRSA）的感染迅速增加下，在過去15年，已成為全球性健康問題。在醫院感染醫療照護相關之methicillin抗藥性金黃色葡萄球菌（Healthcare-associated MRSA, HA-MRSA）對病人死亡率和發病率產生重大影響。
研究目的: (1)研究一 本研究目的是探討抗生素使用量及抗藥性的相關性和應用時間序列預測模型進行分析，解釋抗生素使用量，感染控制措施及抗藥性的關係。(2)研究二 本研究目的是使用多種微生物學分子分型技術分析一個MRSA的群聚感染事件，以微生物學分子分型證據，確立群聚感染事件的感染源，和建立醫院臨床實驗室MRSA 分子生物分型之技術。
研究方法: (1)研究一 本研究第一部份，在探討台灣中部某醫學中心，從2001年至2009年間，在抗生素的管制使用政策下，各全身治療抗生素的抗生素使用量（定義之標準日劑量，defined daily doses，DDD/1000住院人日表示）對MRSA盛行率和HA-MRSA發生率長期之影響。本研究第二部份，以西元2004年1月至2009年12月，在中山醫學大學附設醫院進行，收集每月全身治療注射抗生素使用量、酒精性乾洗手液使用量、醫療照護相關感染發生率和HA-MRSA感染發生率資料，應用時間序列分析預測模型和整合之自我迴歸移動平均模式，分別對各類不同的抗生素使用量和酒精性乾洗手液使用量進行迴歸檢定，探討醫療照護相關感染發生率和HA-MRSA感染發生率（HA-MRSA感染人數/1000住院人日）的關係。每月各全身治療注射抗生素的使用量(DDD/1000住院人日)，每月酒精性乾洗手液使用量以每升/1000住院人日表示。(2)研究二 運用脈衝式電泳(pulsed-field gel electrophoresis; PFGE)，DNA分子指印技術-多重基因座序列分型法(multilocus sequence typing; MLST) ，MRSA藥敏試驗，利用多重PCR檢測及分型，分析MRSA上的SCCmec結構和破壞白血球之毒素的基因（Panton-Valentine leukocidin, pvl）等分型方法，以分析鑑別MRSA菌株相關性。
研究結果 (1)研究一 研究第一部份結果顯示，所有使用於全身治療抗生素使用量減少了33％。這種變化主要是受到非管制抗生素之使用量44％減少的原因，這是抵消了管制抗生素42％的使用量增加。在MRSA流行的趨勢，MRSA的盛行率（分離菌株數/1000住院人日）和HA - MRSA的發生率（HA - MRSA感染的人數/1000住院人日），與全部抗生素總趨勢的相關。可以觀察到，MRSA盛行率與和extended-spectrum - β-lactamase-resistant penicillins，first-generation cephalosporins, macrolides，lincosamides，aminoglycosides，和glycopeptides使用量有顯著的正相關。另外發現HA - MRSA感染發生率和tetracyclines， extended-spectrum - β-lactamase-resistant penicillins，sulfonamides和trimethoprim, macrolides，lincosamides，和aminoglycosides之間使用量顯著正相關。在研究第二部份，多變項分析結果顯示，增加酒精性乾洗手液使用量分別對降低醫療照護相關感染發生率（P = 0.0002）和降低HA-MRSA的發生率（P = 0.0066），有統計學上的顯著性正相關。整合之自我迴歸移動平均模式下，HA-MRSA的發生率模型顯示，在增加使用第三代頭孢子菌抗生素時，經過長達4個月時間遲滯後，會增加HA-MRSA的發生率，在統計學上有顯著性（P = 0.0015）。這個模型解釋了39％的HA-MRSA發生率增加變化。在每增加使用1升/1000住院人日酒精性乾洗手液使用量時，在經過 1個月時間遲滯後，在HA-MRSA感染發生率可以減少0.375人數/1000住院人日，在統計學上有顯著性（P = 0.0066）。這個模型解釋27％的HA-MRSA發生率減少變化。(2)研究二 在2006年3月至6月，中山醫學大學附設醫院中港院區呼吸照護病房中，MRSA感染發生率增加了3.75倍，疑似MRSA群聚感染事件。67位醫護人員的金黃色葡萄球菌帶菌率為31.3％，其中16.4％為MRSA，14.9％為Methicillin敏感金黃色葡萄球菌(MSSA)。脈衝式電泳，DNA多重基因座序列分型法，MRSA藥敏試驗，多重PCR檢測及pvl基因分型等分型方法，提供明顯的流行病學和微生物學證據證明，在此次院內感染MRSA的群聚感染源，是來自同一MRSA菌株，其中七位醫護人員和五位病人帶有脈衝式電泳pulsotype A， SCCmec II型，pvl基因分型陰性，MLST ST5型之MRSA菌株。這次群聚感染事件，在所有帶有MRSA移生醫護人員之前鼻孔塗抹外用fucidin藥膏，一個星期後，後續追踪結果，沒有發現醫護人員有MRSA移生情況，最後疫情得到控制。
研究結論：(1)研究一 在抗生素管制使用政策下，減少全身治療抗生素使用量與HA-MRSA發生率呈顯著正相關。研究結果證明持續超過 9年的成功減少抗生素總使用量，與HA - MRSA感染的發生率和MRSA盛行率的減少有顯著相關。研究結果發現應用時間序列分析預測模型，可以解釋感染控制措中，增加酒精性乾洗手液使用量和減少醫療照護相關感染發生率與HA-MRSA發生率的關係。使用兩種不同的研究設計，來解釋在抗生素管制政策和感染控制措的影響下，對改變抗生素抗藥性複雜的問題，並希望這些結果可以幫助我們未來減少抗生素抗藥性的產生。(2)研究二 在平常臨床實驗室中，當結合脈衝式電泳，DNA多重基因座序列分型法，MRSA藥敏試驗，多重PCR檢測及pvl基因分型等分型方法，是一個可行和有效的方法，運用於MRSA群聚感染事件的疫情調查。

關鍵字

抗生素使用量 ； 抗生素管制政策 ； Methicillin抗藥性金黃色葡萄球菌 ； 抗藥性 ； 時間序列分析預測模型 ； 醫療照護相關感染控制措施 ； 酒精性乾洗手液 ； 醫療照護相關感染 ； 脈衝式電泳 ； DNA多重基因座序列分型法 ； 藥敏試驗 ； 多重PCR檢測

並列摘要

Background: The importance of methicillin-resistant Staphylococcus aureus (MRSA) infection antimicrobial resistance has increased rapidly during the last 15 years and has become a global health issue. MRSA infections have an enormous impact on the mortality and morbidity in the hospital settings.
Objectives: (1) Study 1: The objective of study 1 is to use the correlation between antimicrobial consumption and antimicrobial resistance and apply the forecasting models performed time series analysis to explain the relationship antimicrobial consumption, infection control measures and antibiotic resistance. (2) Study 2: The objective of study 2 is to use molecular typing techniques and to identify the most feasible methods for routine clinical setting to investigate MRSA isolates in a standard clinical laboratory. We also aimed to use the results of these molecular methods to characterize the MRSA strains isolated from health care workers (HCWs) and patients during an outbreak in a respiratory care ward in central Taiwan.
Methods: (1) Study 1: We investigated the long-term impact of antibiotic use policy on the rates of consumption (expressed as daily-defined doses (DDD) per 1000 patient days (PD)) of various parenteral antibiotics, the prevalence of MRSA, and incidence of healthcare-associated MRSA (HA-MRSA, persons/1000 PD) infection at Chung Shan Medical University Hospital (CSMUH) from 2001 to 2009. Using time-series analysis based on monthly data during 6 year period (January 2004 to December 2009). The different antimicrobials consumption and alcohol-based hand rub were separately regressed to explore the relationship of incidence of healthcare-associated infection (HAI) and HA-MRSA (persons/1000 PD). Monthly alcohol-based hand rub consumption was expressed in liters/1000 PD. (2) Study 2: We used the methods include Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), antibiograms derived from susceptibility testing of MRSA isolates, and multiplex PCR for detection of staphylococcal cassette chromosome (SCC)mec typing and Panton-Valentine leukocidin (pvl) gene typing to discriminate MRSA isolates.
Results: (1) Study 1: During this time, the consumption of all antimicrobials for systemic use decreased by 33%. This change was driven by a 44% decrease in the consumption of the unrestricted antibacterials, which was offset by a 42% increase in the consumption of the restricted agents. The trends in MRSA prevalence (number of isolates per 1000 PD) and HA-MRSA incidence (number of HA-MRSA-infected persons per 1000 PD) correlated with the trend in overall consumption of the antimicrobials. Significant positive correlations were observed between MRSA prevalence and the consumption of extended-spectrum and β-lactamase-resistant penicillins, first-generation cephalosporins, macrolides, lincosamides, aminoglycosides, and glycopeptides. Significant positive correlations were found between the incidence of HA-MRSA infection and the consumption of tetracyclines, extended-spectrum and β-lactamase-resistant penicillins, sulfonamides and trimethoprim, macrolides, lincosamides, and aminoglycosides. The multivariate analysis showed that using alcohol-based hand rub for hand hygiene practice had a statistical significant effectiveness on the HAI (P = 0.0002) and HA-MRSA incidence (P = 0.0066). An increasing alcohol-based hand rub consumption was subsequently associated with reduce incidence of HAI and HA-MRSA incidence. In HA-MRSA incidence model showed that temporal increase in the use of third-generation cephalosporins (P = 0.0015) is, after a time lag of up to 4 months, followed by temporal increase in the incidence of HA-MRSA significantly. This model explained 39% of the monthly variations in the incidence of HA-MRSA. An increasing alcohol-based hand rub consumption of one liters/1000 PD are associated with decreasing 0.375 persons/1000 PD HA-MRSA Infection, after one month later. This model explained 27 % of the monthly variations in the incidence of HA-MRSA. (2) Study2: From March to June 2006, the incidence of MRSA infection increased 3.75-fold. The overall carrier rates among the HCWs were 31.3% (21/67, total S. aureus) and 16.4% (MRSA), and 14.9% (methicillin-sensitive SA, MSSA). PFGE, MLST, antibiograms derived from susceptibility testing of MRSA isolates, multiplex PCR typing and pvl gene typing provided strong epidemiologic and microbiologic evidence that an outbreak of MRSA infections at our hospital was linked to the same PFGE pulsotype A SCCmec type II, pvl negative, MLST ST5 strain of MRSA isolated from seven HCWs and five patients. The outbreak was controlled by application of topical fucidin ointment to the anterior nares by all HCWs colonized with MRSA. After one week’s treatment with fucidin ointment, follow-up cultures revealed no colonization by MRSA, and no new infections arose among the patients.
Conclusions: (1) Study1: We have documented the ongoing successful reduction in total consumption of antimicrobials associated with a decrease in the incidence of HA-MRSA and prevalence of MRSA over a 9-year period. We successfully applied forecasting model to demonstrate the increase alcohol-based hand rub consumption was correlated with reduction the incidence of HAI and HA-MRSA, and reductions in individual restricted antimicrobials were significantly positively correlated with decreases in the incidence of HA-MRSA infections. (2) Study 2: We used molecular typing methods to investigate of an outbreak of MRSA infection in a respiratory care ward in Taiwan. We conclude that multiplex PCR is a feasible and useful method combination with PFGE for outbreak investigations in routine clinical laboratories.

並列關鍵字

Antimicrobial consumption ； antimicrobial stewardship program ； antimicrobial resistance ； methicillin-resistant Staphylococcus aureus ； time series analysis ； infection control measures ； alcohol-based hand rub ； healthcare-associated infection ； PFGE ； multiplex PCR ； MLST ； Outbreak

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