Leahy Timothy Ronan, Yau Yvonne C W, Atenafu Eshetu, Corey Mary, Ratjen Felix, Waters Valerie
Institute of Molecular Medicine, St James's Hospital, James's St, Dublin 8, Ireland.
Pediatr Pulmonol. 2011 May;46(5):489-96. doi: 10.1002/ppul.21383. Epub 2011 Feb 17.
A single-center retrospective study was undertaken in children with cystic fibrosis (CF) to evaluate (1) risk factors for acquisition; (2) molecular epidemiology; and (3) impact on disease progression of borderline oxacillin-resistant Staphylococcus aureus (BORSA) versus mecA-positive methicillin-resistant Staphylococcus aureus (MRSA). The study comprised of (1) identification of all children with at least one respiratory specimen positive for either BORSA or MRSA during the study period; (2) compilation of relevant clinical and epidemiological data from 12-month period leading up to first positive (index) culture; (3) microbiological and molecular characterization of index isolates and (4) measurement of subsequent clinical outcome. Thirty-eight children were identified with at least one positive isolate; 4 were excluded due to insufficient clinical or laboratory data. Eighteen children (53%) grew BORSA in their index culture. Children who acquired BORSA only (n = 16) were more likely to have had prior MSSA colonization (P < 0.0001). Usage of oral cephalexin (P < 0.01) and inhaled tobramycin (P < 0.03) prior to index culture was significantly and independently associated with acquisition of BORSA. The majority of BORSA isolates were hyper β-lactamase producers and susceptible to a greater range of antibiotics. Strain relatedness was not evident within the BORSA group. There was no difference in disease progression between the two groups. This is the first study to demonstrate that a significant proportion of S. aureus isolates with methicillin resistance in the CF population are BORSAs that lack mecA. Antibiotic pressure may lead to the development of BORSA in CF patients. Prospective studies are needed to assess its clinical impact.
一项针对囊性纤维化（CF）患儿的单中心回顾性研究，旨在评估：（1）感染的危险因素；（2）分子流行病学；（3）对苯唑西林耐药金黄色葡萄球菌（BORSA）与mecA阳性耐甲氧西林金黄色葡萄球菌（MRSA）疾病进展的影响。该研究包括：（1）确定研究期间所有至少有一份呼吸道标本检测出BORSA或MRSA阳性的儿童；（2）收集首次阳性（索引）培养前12个月期间的相关临床和流行病学数据；（3）对索引菌株进行微生物学和分子特征分析；（4）测量后续临床结果。共确定38名儿童至少有一份阳性菌株；4名因临床或实验室数据不足被排除。18名儿童（53%）在索引培养中培养出BORSA。仅感染BORSA的儿童（n = 16）更有可能曾有过甲氧西林敏感金黄色葡萄球菌（MSSA）定植（P < 0.0001）。索引培养前口服头孢氨苄（P < 0.01）和吸入妥布霉素（P < 0.03）的使用与BORSA感染显著且独立相关。大多数BORSA菌株是超β-内酰胺酶产生菌，对更多种类的抗生素敏感。BORSA组内菌株相关性不明显。两组之间疾病进展无差异。这是第一项表明CF人群中相当一部分耐甲氧西林的金黄色葡萄球菌分离株是缺乏mecA的BORSA的研究。抗生素压力可能导致CF患者出现BORSA。需要进行前瞻性研究以评估其临床影响。
