People with diabetes mellitus, especially insulin-dependent diabetic patients, are a risk group for staphylococcal infections. Asymptomatic infection with Staphylococcus aureus is common and favors dissemination of the microorganism, rendering these individuals a source of infection. This study aimed to characterize the resistance profile, clonal profile and sequence type, as well as to analyze the prevalence and risk factors for nasal and oropharyngeal carriage of methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) isolated from insulin-dependent diabetic individuals in the city of Botucatu, SP, Brazil. Staphylococcus aureus was collected from the nasopharynx and oropharynx of 312 community-dwelling insulin-dependent diabetic individuals over a period of 3 years (October 2015 to December 2018). The isolates were characterized by susceptibility profiling, detection of the mecA gene, SCCmec typing, and molecular typing by PFGE and MLST. The risk factors associated with S. aureus and MRSA carriage were determined by logistic regression analysis. The overall prevalence of colonization with S. aureus and MRSA was 30.4% and 4.8%, respectively. Fifteen of the 112 S. aureus isolates carried the mecA gene; SCCmec type IV was identified in 10 isolates, SCCmec type I in three, and SCCmec type II in two. Among the 15 resistant isolates (MRSA), four were susceptible to oxacillin/cefoxitin by the disc diffusion method and one MSSA isolate was resistant to sulfamethoxazole/trimethoprim. The analysis of risk factors revealed a protective effect of age and lung disease, while lower-extremity ulcers were a risk factor for S. aureus. For MRSA, only male gender was significantly associated as a risk factor in multivariate analysis. Clonal profile analysis demonstrated the formation of clusters among MRSA isolates from different patients, with the identification of ST5-IV, ST5-I, and ST8-IV. Isolates carrying ST398 were identified among MSSA and MRSA (ST398-IV). Our findings reinforce the importance of epidemiological studies of S. aureus carriage, especially in populations at high risk of infections such as diabetics. The data suggest widespread dissemination of MRSA in the population of insulin-dependent diabetic patients studied, as well as the emergence of important lineages among these individuals.

中文翻译：

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巴西胰岛素依赖型糖尿病患者中耐甲氧西林金黄色葡萄球菌的分子特征


糖尿病患者，尤其是胰岛素依赖型糖尿病患者，是葡萄球菌感染的高危人群。金黄色葡萄球菌的无症状感染很常见，有利于微生物的传播，使这些人成为感染源。本研究旨在表征耐药谱、克隆谱和序列类型，并分析从胰岛素中分离出的甲氧西林敏感金黄色葡萄球菌 (MSSA) 和耐甲氧西林金黄色葡萄球菌 (MRSA) 鼻腔和口咽携带的流行率和危险因素巴西圣保罗州博图卡图市的糖尿病患者。金黄色葡萄球菌是在 3 年期间（2015 年 10 月至 2018 年 12 月）从 312 名社区居住的胰岛素依赖型糖尿病患者的鼻咽和口咽中收集的。通过药敏分析、mecA 基因检测、SCCmec 分型以及 PFGE 和 MLST 进行分子分型来表征分离株。通过逻辑回归分析确定与金黄色葡萄球菌和 MRSA 携带相关的危险因素。金黄色葡萄球菌和 MRSA 定植的总体患病率分别为 30.4% 和 4.8%。 112 个金黄色葡萄球菌分离株中，有 15 个携带 mecA 基因；在 10 个分离株中鉴定出 SCCmec IV 型，在 3 个分离株中鉴定出 SCCmec I 型，在 2 个分离株中鉴定出 SCCmec II 型。通过纸片扩散法，15 株耐药菌株 (MRSA) 中，4 株对苯唑西林/头孢西丁敏感，1 株 MSSA 菌株对磺胺甲恶唑/甲氧苄啶耐药。对危险因素的分析显示，年龄和肺部疾病具有保护作用，而下肢溃疡是金黄色葡萄球菌的危险因素。对于 MRSA，在多变量分析中，只有男性与作为危险因素显着相关。 克隆谱分析表明来自不同患者的 MRSA 分离株之间形成簇，并鉴定出 ST5-IV、ST5-I 和 ST8-IV。在 MSSA 和 MRSA (ST398-IV) 中鉴定出携带 ST398 的分离株。我们的研究结果强调了金黄色葡萄球菌携带流行病学研究的重要性，特别是在糖尿病患者等感染高危人群中。数据表明，MRSA 在所研究的胰岛素依赖型糖尿病患者群体中广泛传播，并且在这些个体中出现了重要的谱系。