(一) 研究背景

　　菌血症為所有細菌感染中最為嚴重的感染，而血液培養是唯一能確立菌血症診斷的依據。然而，採血過程中常受皮膚表面菌叢污染，而導致培養結果誤判及抗生素的不適當使用。過去有關臨床判讀血液培養結果為污染或確實感染的標準，卻以臨床醫師是否使用抗生素治療為依據，且這些標準缺乏實際臨床介入的研究證實。本研究參考過去相關判別標準與感染科醫師之意見，訂定一套處置流程及判別標準，以藥師實際臨床介入探討其對抗生素使用之影響及介入之成效。

(二)研究目的

1.了解藥師介入對節制血液培養污染導致抗生素不當使用之影響，探討的重點包括抗生素使用天數、使用量、花費，及醫師之處置行為。
2.了解藥師介入抗生素之使用對病患死亡率及住院情形之影響。

(三)研究方法

研究分實驗組及對照組進行分析及比較：
1.實驗組－採前瞻性介入方式：（1）擬訂懷疑血液培養污染處置流程，於各病房宣導。（2）針對2004年2月至5月間血液培養結果為常見血液培養污染菌（簡稱「偽菌血症」）之個案，進行個別追蹤，對不適當處置之個案作建議性之介入。
2.對照組－採回溯性評估方式：針對2003年2月至5月間血液培養結果為常見血液培養污染菌之個案，進行病歷查閱分析，評估醫師處方抗生素情形、加作血液培養或照會感染科醫師情形，及抗生素使用天數、花費。
3.結果評估－比較兩組偽菌血症病患抗生素使用率、使用天數及花費、醫師加作血液培養率，以及病患之死亡率及住院情形。

(四)研究結果

實驗組與對照組分別收納106位病患，其中偽菌血症病患分別有91位及87位。血液培養污染率分別為86%及82%。實驗組加護病房病患比率明顯較對照組少（23% v.s. 37%，p=0.046）。在比較兩組之抗生素使用率時，實驗組抗生素使用率明顯較對照組少（33% v.s. 49%，p=0.026）。個別分析非加護病房病患，則發現實驗組之抗生素使用率明顯較對照組少（34% v.s. 56%，p=0.014）。實驗組病患於血液培養報告日後抗生素使用天數明顯較對照組短（中位數3.5天v.s. 5.0天，p=0.022），而抗生素使用量及花費則有下降趨勢，但未達統計上顯著差異之程度。實驗組與對照組病患在報告日後第7天及第14天之死亡率、住院率、出院率皆無顯著差異。顯示藥師介入抗生素使用，並未影響到病患之預後。醫師之處置方面，實驗組加作血液培養率明顯較對照組高（34% v.s. 21%，p=0.046），有使用抗生素之病患加作血液培養率增加更為明顯（63% v.s. 16%，p<0.001）。

(五)結論
　　藥師介入能降低非加護病房偽菌血症病患之抗生素使用率，即使對於使用抗生素之病患，亦能縮短其抗生素使用天數。醫師處置方面，藥師之介入提升了臨床醫師加作血液培養確認之比率，特別是在使用抗生素病患。病患死亡率及住院情形並不會因藥師介入而顯著改變。

OBJECTIVE
　　To assess if pharmacist’s intervention reduces inappropriate uses of antibiotics in blood culture contamination, and to know the impact of pharmacist intervention on patients’ outcomes.

DESIGN
　　This study was a prospective intervention protocol using historical group as control. We developed a management guideline for adult cases with suspected pseudobacteremia. The management guideline was advocated in the inpatient wards in National Cheng-Kung University Hospital in February 2004. From February 2004 to May 2004, the pharmacist followed the patients with positive blood cultures of common contaminants. The pharmacist gave suggestions to physicians if their managements did not comply with the guideline. Moreover, the medical charts of adult cases with pseudobacteremia during February 2003 to May 2003 were reviewed, regarding as the control group. The antibiotic uses and the outcomes of patients with pseudobacteremia were compared.

SETTING
National Cheng-Kung University Hospital, Tainan, Taiwan.

RESULTS
　　Each of the intervention group and the control group enrolled 106 cases. Ninety-one patients in the intervention group and 87 in the control group were considered to have pseudobacteremia, with similar contamination rates of 86% and 82%, respectively. The proportion of patients in the intensive care units (ICU) was significantly less in the intervention group (23% v.s. 37%, p=0.046). Antibiotics were prescribed less frequently in the intervention group (33% v.s. 49%, p=0.026), and a similar result was noted for the non-ICU patients in the intervention group (34% v.s. 56%, p=0.014). Among those with pseudobacteremia treated with antimicrobial agents, the duration of antibiotic therapy in the intervention group was shorter (median duration, 3.5 v.s. 5.0 days, p=0.022). Repetition of blood cultures at the availability of results of initial blood cultures occurred more often in the intervention group (34% v.s. 21%, p=0.046), especially among the cases with antibiotic therapy (63% v.s. 16%, p<0.001). Clinical outcomes, such as case mortality rate, hospitalization rate or discharge rate at day 7 or day 14 were not significantly different between the two groups.

CONCLUSION
　　Antimicrobial agents are quite frequently used for cases with contaminated blood cultures. In cases with suspected pseudobacteremia, pharmacist intervention based on established guidelines can decrease the unnecessary prescriptions of antimicrobial agents. For those using antibiotics, pharmacist intervention can reduce the duration of usage. Such interventions do not affect their clinical outcomes.

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