Specimens’ details.

PurposeTo assess the in vitro efficacy of common antimicrobial agents used empirically for methicillin- resistant and sensitive Staphylococcus aureus (MRSA and MSSA) infections of the lacrimal system.MethodsA retrospective review of culture-proven S. aureus isolates retrieved from lacrimal system samples collected between January 2013–December 2022 was performed. Microbiologic characteristics such as in vitro susceptibility as well as clinical characteristics including history of recent ocular surgery, presence of lacrimal biomaterial implant, anti-microbial regimen, and treatments outcome were collected.ResultsOne hundred and sixteen S. aureus isolates (patients = 116) were identified. Thirty-one (27.4%) and 22 (19.5%) patients had recent ocular procedure and lacrimal intubation, respectively. Fifty (44.2%) patients received a combination of oral and topical antibiotics as first line of treatment. The most common empirically utilized antibiotics were β-lactams (38.9%) and polymyxin B/ trimethoprim (31.0%). The antibiotic regimen was changed at least once in 20.5% of patients due to ineffectiveness. Of the patients with positive cultures from the lacrimal excretory apparatus, 37.3% underwent surgery as part of the treatment approach. Of all isolates identified 44.8% were MRSA. Among the fluoroquinolones, the resistance rate was 38.8% for ciprofloxacin and 30.4% for moxifloxacin, with significantly higher resistance rates in MRSA (P-value ConclusionsThere is low in vitro efficacy of commonly used antimicrobials such as β-lactams and fluoroquinolones in our study population; thus, we recommend opting for trimethoprim/sulfamethoxazole and gentamicin for systemic and topical single-agent treatments.

## 研究目的
本研究旨在评估经验性用于泪道系统甲氧西林耐药金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus, MRSA）与甲氧西林敏感金黄色葡萄球菌（methicillin-sensitive Staphylococcus aureus, MSSA）感染的常用抗菌药物的体外疗效。

## 研究方法
本研究对2013年1月至2022年12月期间采集的泪道系统样本中经培养证实的金黄色葡萄球菌分离株开展回顾性分析。研究收集了两类数据：其一为微生物学特征，包括体外药敏特性；其二为临床特征，涵盖近期眼部手术史、泪道生物材料植入情况、抗菌治疗方案及治疗结局。

## 研究结果
本研究共鉴定出116株金黄色葡萄球菌分离株，对应116例患者。其中31例（27.4%）患者近期接受过眼部操作，22例（19.5%）患者曾行泪道插管术。50例（44.2%）患者以口服联合局部抗生素作为一线治疗方案。临床最常使用的经验性抗菌药物为β-内酰胺类（38.9%）与多粘菌素B/甲氧苄啶（31.0%）。20.5%的患者因治疗无效，至少调整过一次抗菌治疗方案。在泪道排泄装置培养阳性的患者中，37.3%的患者接受手术作为治疗手段之一。所有分离株中44.8%为MRSA。在氟喹诺酮类药物中，环丙沙星的耐药率为38.8%，莫西沙星为30.4%，MRSA菌株的耐药率显著更高（P值原文未完整给出）。

## 研究结论
本研究人群中，β-内酰胺类与氟喹诺酮类等常用抗菌药物的体外抗菌活性较低；因此，我们推荐选用甲氧苄啶/磺胺甲噁唑与庆大霉素作为全身与局部单药治疗方案。