Zavascki Alexandre Prehn, Gaspareto Patrick Barcelos, Martins Andreza Francisco, Gonçalves Ana Lúcia, Barth Afonso Luís
Infectious Diseases Service, Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
J Antimicrob Chemother. 2005 Dec;56(6):1148-51. doi: 10.1093/jac/dki390. Epub 2005 Oct 20.
To describe the first nosocomial outbreak of Pseudomonas aeruginosa producing SPM-1 metallo-beta-lactamase (MBL) in southern Brazil.
From January to October 2004, carbapenem-resistant P. aeruginosa (CRPA) were recovered from hospitalized patients. Mortality, site of infection/colonization, patient location and susceptibility profiles were analysed. A sample of CRPA was screened for MBL production, evaluated for the presence of bla(SPM-1), bla(IMP-1) and bla(VIM-2) genes by PCR and submitted for molecular typing by DNA macrorestriction.
A total of 135 CRPA (one isolate per patient) were recovered. Two major antibiotic susceptibility profiles comprised 63.7% of the isolates (susceptibility to polymyxin B and aztreonam, and susceptibility only to polymyxin B). Thirty-five CRPA were screened for MBL production (10 isolates from April, June and July, and 25 from September and October) and 27 (77.1%) proved to be positive for MBL production. Twenty-one of the 24 CRPA tested carried the bla(SPM-1) gene. The mortality of patients with CRPA was 48.1% and no variable was associated with death. Molecular typing revealed the presence of a clone with four related subtypes among the bla(SPM-1)-positive CRPA.
The prevalence of MBL production by CRPA is high and horizontal transmission is a major determinant for the spread of SPM-1 CRPA among patients in this institution. As infection control measures failed to control the spread of CRPA, continuous surveillance for MBL production is warranted.
描述巴西南部首例医院内产SPM-1金属β-内酰胺酶（MBL）的铜绿假单胞菌暴发情况。
2004年1月至10月，从住院患者中分离出耐碳青霉烯类铜绿假单胞菌（CRPA）。分析死亡率、感染/定植部位、患者所在位置及药敏谱。对CRPA样本进行MBL产生情况筛查，通过聚合酶链反应（PCR）评估bla(SPM-1)、bla(IMP-1)和bla(VIM-2)基因的存在情况，并进行DNA宏观限制性分析以进行分子分型。
共分离出135株CRPA（每位患者一株分离株）。两种主要的抗生素药敏谱占分离株的63.7%（对多粘菌素B和氨曲南敏感，以及仅对多粘菌素B敏感）。对35株CRPA进行MBL产生情况筛查（4月、6月和7月的10株分离株，以及9月和10月的25株分离株），27株（77.1%）MBL产生检测呈阳性。检测的24株CRPA中有21株携带bla(SPM-1)基因。CRPA患者的死亡率为48.1%，且无变量与死亡相关。分子分型显示在bla(SPM-1)阳性的CRPA中存在一个具有四种相关亚型的克隆。
CRPA产生MBL的发生率很高，水平传播是该机构中SPM-1 CRPA在患者中传播的主要决定因素。由于感染控制措施未能控制CRPA的传播，因此有必要持续监测MBL的产生情况。
