Yang Wei, He Bei, Ning Yong-zhong, Li Yun
Department of Respiratory Medicine, Peking University Third Hospital, Beijing 100191, China.
Zhonghua Jie He He Hu Xi Za Zhi. 2013 Apr;36(4):288-92.
To investigate the change and significance of vancomycin minimal inhibitory concentration (MIC) against methicillin-resistant Staphylococcus aureus (MRSA) isolates.
We analyzed the data of inpatients with lower respiratory tract infection, with positive cultures of MRSA from airway samples, at respiratory ward or respiratory intensive care unit (RICU) between 2000 and 2011. The MIC of vancomycin was determined by the agar dilution method.
There were 295 patients [210 males, 85 females, mean age (73 ± 12) years (range, 18 - 98)] with a positive culture of MRSA from airway samples. The arithmetic mean of vancomycin MIC against MRSA isolates fluctuated from 0.99 to 1.60 mg/L. The number of defined daily doses (DDDs) of vancomycin from the whole hospital had an influence on the mean of vancomycin MIC in the next year (r = 0.64, P = 0.04). But the vancomycin DDDs from respiratory department were not related with the mean of vancomycin MIC in the next year (r = 0.33, P = 0.32). The patients were divided into 2 groups according the MIC of vancomycin against MRSA isolates: MIC = 2 mg/L group (n = 43) and MIC < 2 mg/L group (n = 252). There was no difference in mortality [14 cases (32.6%) and 73 cases (29.0%)] (χ(2) = 0.23, P = 0.63), the clinical success rates 26 cases (60.5%) and 156 cases (61.9%) = 0.03, P = 0.85) and bacterial success rates [21 cases (48.8%) and 106 cases (42.1%)] (χ(2) = 1.20, P = 0.27) between the 2 groups. But the average hospitalization days were significantly prolonged (Z = 3.09, P = 0.00)in the MIC = 2 mg/L group [40(27, 93) days]as compared to that in the MIC < 2 mg/L group [30 (20, 52) days]. The average treatment time [10 (1, 19) days and 3(0, 12) days, Z = -2.79, P < 0.01] was also longer in the MIC = 2 mg/L group. In a multiple stepwise regression analysis, male gender (OR = 3.58) and acute physiology and chronic health evaluation II (APACHE II) scores (OR = 1.06) were independently associated with vancomycin MIC = 2 mg/L.
In inpatients with MRSA lower respiratory tract infection at respiratory ward or RICU between 2000 and 2011, the vancomycin MIC fluctuated, which was related with vancomycin DDDs from the whole hospital. The average hospitalization days and treatment time were significantly prolonged in patients with MRSA isolates with a higher vancomycin MIC (= 2 mg/L). APACHE II score was an independent risk factor for vancomycin MIC being 2 mg/L.
探讨万古霉素对耐甲氧西林金黄色葡萄球菌（MRSA）分离株的最低抑菌浓度（MIC）的变化及意义。
我们分析了2000年至2011年间呼吸内科病房或呼吸重症监护病房（RICU）下呼吸道感染住院患者的数据，这些患者气道样本中MRSA培养呈阳性。采用琼脂稀释法测定万古霉素的MIC。
共有295例患者[男性210例，女性85例，平均年龄（73±12）岁（范围18 - 98岁）]气道样本中MRSA培养呈阳性。万古霉素对MRSA分离株的算术平均MIC在0.99至1.60mg/L之间波动。全院万古霉素的限定日剂量（DDDs）数量对次年万古霉素MIC的均值有影响（r = 0.64，P = 0.04）。但呼吸科的万古霉素DDDs数量与次年万古霉素MIC的均值无关（r = 0.33，P = 0.32）。根据万古霉素对MRSA分离株的MIC将患者分为2组：MIC = 2mg/L组（n = 43）和MIC < 2mg/L组（n = 252）。两组在死亡率[14例（32.6%）和73例（29.0%）]（χ² = 0.23，P = 0.63）、临床成功率[26例（60.5%）和156例（61.9%）]（χ² = 0.03，P = 0.85）和细菌清除率[21例（48.8%）和106例（42.1%）]（χ² = 1.20，P = 0.27）方面无差异。但与MIC < 2mg/L组[30（20，52）天]相比，MIC = 2mg/L组[40（27，93）天]的平均住院天数显著延长（Z = 3.09，P = 0.00）。MIC = 2mg/L组的平均治疗时间[10（1，19）天和3（0，12）天，Z = -2.79，P < 0.01]也更长。在多元逐步回归分析中，男性（OR = 3.58）和急性生理与慢性健康状况评分II（APACHE II）（OR = 1.06）与万古霉素MIC = 2mg/L独立相关。
在2000年至2011年间呼吸内科病房或RICU的MRSA下呼吸道感染住院患者中，万古霉素MIC波动，这与全院万古霉素的DDDs数量有关。万古霉素MIC较高（= 2mg/L）的MRSA分离株患者的平均住院天数和治疗时间显著延长。APACHE II评分是万古霉素MIC为2mg/L的独立危险因素。
