来自各种眼部感染的表皮葡萄球菌分离株中黏附操纵子基因的不同基因型

Different Genotypes of Adhesion Operon Genes in Staphylococcus epidermidis Isolates From Various Ocular Infections.

作者信息

Sharifinejad Mehrnoush, Shokatpour Narjes, Farnaghi Farshad, Abedinyfar Zohreh, Amoli Fahimeh Asadi, Doustdar Farahnoosh

机构信息

Infectious Diseases and Tropical Medicine Research Center (M.S.), Shahid Beheshti University of Medical Sciences, Tehran, Iran; Faculty of Basic Sciences (M.S.), Islamic Azad University, Damghan Branch, Damghan, Iran; Department of Microbiology (N.S.), Faculty of Biological Sciences, Shahid Beheshti University, Tehran, Iran; Department of Microbiology (F.F., Z.A., F.D.), Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; and Department of Pathology (F.A.A.), Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

出版信息

Eye Contact Lens. 2018 Nov;44 Suppl 2:S277-S280. doi: 10.1097/ICL.0000000000000464.

DOI:10.1097/ICL.0000000000000464

PMID:29280751

Abstract

BACKGROUND

Staphylococcus epidermidis is one of the common causes of bacterial keratitis and post-operation infections. One of the most important virulence factors of S. epidermidis is biofilm formation. Poly-N-acetylglucosamine (PNAG) production is critical for biofilm formation in S. epidermidis. The intercellular adhesion (ica) operon is formed by icaA, icaD, icaB, and icaC genes, which participate in the biosynthesis of PNAG. Strains of S. epidermidis from different infections show different genotypes in relation to adhesion operon genes. Therefore, regarding the fact that the pathogenic strain in each community has unique genotypes, this study investigated the relation between ica operon genotypes and various ocular infections. However, the correlation between the ica operon genes and the mecA gene was analyzed in the isolates.

METHODS

For this study, samples of the conjunctiva, cornea, and intraocular fluid of patients with ocular infection were collected. After culture and incubation, detection of S. epidermidis was performed using biochemical and coagulase tests. The antibiotic susceptibility of the bacteria was evaluated by the disk diffusion method. After this, DNA was extracted from the bacteria and the presence of icaA, icaD, is256, and mecA genes was analyzed using polymerase chain reaction.

RESULTS

All 50 coagulase-negative Staphylococcus samples isolated from different eye infections were characterized as S. epidermidis. Most of the samples (36%) were isolated from the cornea and the others were, respectively, from the conjunctiva (24%), vitreous (20%), anterior chamber (8%), eyelid (6%), and nasolacrimal duct (6%). The icaA, icaD, and is256 genes were detected with different genotypes in isolates from keratitis and endophthalmities compared with conjunctivitis. Overall, the most isolated genotype from ocular infections was icaA+. icaD+. is256+. (46%). Most of the isolates (82.60%) had mecA, icaA, and icaD genes simultaneously, which indicates a strong relationship between the adhesion genes and the antibiotic resistance gene.

CONCLUSIONS

The adhesion operon genes were observed with different genotypes in S. epidermidis samples isolated from various ocular infections.

摘要

背景

表皮葡萄球菌是细菌性角膜炎和术后感染的常见病因之一。表皮葡萄球菌最重要的毒力因子之一是生物膜形成。聚-N-乙酰葡糖胺（PNAG）的产生对表皮葡萄球菌生物膜的形成至关重要。细胞间黏附（ica）操纵子由icaA、icaD、icaB和icaC基因组成，这些基因参与PNAG的生物合成。来自不同感染的表皮葡萄球菌菌株在黏附操纵子基因方面表现出不同的基因型。因此，鉴于每个群体中的致病菌株具有独特的基因型，本研究调查了ica操纵子基因型与各种眼部感染之间的关系。然而，对分离株中ica操纵子基因与mecA基因之间的相关性进行了分析。

方法

在本研究中，收集了眼部感染患者的结膜、角膜和眼内液样本。经过培养和孵育后，使用生化和凝固酶试验对表皮葡萄球菌进行检测。通过纸片扩散法评估细菌的抗生素敏感性。此后，从细菌中提取DNA，并使用聚合酶链反应分析icaA、icaD、is256和mecA基因的存在情况。

结果

从不同眼部感染中分离出的所有50株凝固酶阴性葡萄球菌样本均被鉴定为表皮葡萄球菌。大多数样本（36%）从角膜分离得到，其他样本分别来自结膜（24%）、玻璃体（20%）、前房（8%）、眼睑（6%）和鼻泪管（6%）。与结膜炎相比，在角膜炎和眼内炎的分离株中检测到icaA、icaD和is256基因具有不同的基因型。总体而言，眼部感染中最常见的分离基因型是icaA+、icaD+、is256+（46%）。大多数分离株（82.60%）同时具有mecA、icaA和icaD基因，这表明黏附基因与抗生素耐药基因之间存在密切关系。