In vivo confocal microscopy for the detection of canine fungal keratitis and monitoring of therapeutic response
In vivo confocal microscopy for the detection of canine fungal keratitis and monitoring of therapeutic response
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DOI：
10.1111/vop.12200
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发表时间：
2016-05-01
影响因子：
1.6
通讯作者：
Starr, Jennifer K.
中科院分区：
文献类型：
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作者：
Ledbetter, Eric C.;Norman, Mary L.;Starr, Jennifer K.
目的了解自然获得性细菌性角膜炎犬耐甲氧西林葡萄球菌(MRS)的流行情况及其危险因素。用细菌学方法对2年来从患角膜炎的狗的角膜标本中分离的甲氧西林耐药性进行评估。每个MRS分离株都接受了系统和眼部抗菌药的体外药敏试验。从所有接受MRS角膜隔离的狗身上收集鼻拭子进行培养，以评估鼻腔携带情况。通过查阅病历和对狗主人进行流行病学调查，调查了MRS隔离的潜在危险因素。收集的表征动物、客户和环境变量的信息被分析与MRS分离的相关性。在研究期间，从70只患角膜炎的狗身上分离出。17株葡萄球菌(23.9%)对甲氧西林耐药。MRS分离株包括表皮葡萄球菌10株，假中间葡萄球菌6株，金黄色葡萄球菌1株。MRS角膜分离株表现出广泛的抗菌素耐药性。4只(23.5%)MRS分离犬鼻腔培养阳性，MRS患者职业与MRS隔离显著相关(P=0.01)，属于兽医或人类医疗保健领域的主人的狗患MRS角膜炎的可能性是不同职业客户的狗的4倍。结论甲氧西林耐药在角膜感染犬的葡萄球菌中较为常见，尤其是在医护人员的犬中。目的描述真菌性角膜炎临床病程中犬的活体角膜共聚焦显微镜检查结果，并与临床评价和体外实验犬真菌性角膜炎模型相关联。动物研究了7只自然获得性真菌性角膜炎犬和实验感染临床分离真菌的犬角膜。最初的共聚焦显微镜检查有助于确定真菌性角膜炎的诊断。连续共聚焦显微镜检查以指导抗真菌化疗。结果从实验感染的犬角膜标本中分离到的真菌包括白色念珠菌、木立镰刀菌、厚皮马拉色菌和红酵母。共聚焦显微镜下可见丝状真菌性角膜炎呈线状、分枝状、互锁状、高反光结构，酵母菌角膜炎可见圆形至椭圆形高反光结构。抗真菌化疗与角膜真菌成分分布和密度的进行性减少、真菌形态的改变、白细胞数量的减少、上皮层的恢复和可见的角质细胞核数量的增加有关。停药后无一只狗出现真菌性角膜炎复发。结论在体角膜共聚焦显微镜是一种快速诊断真菌性角膜炎的方法，为临床疗效监测提供了一种无创的机制。
ObjectiveTo determine the prevalence of, and risk factors for, methicillin-resistant Staphylococcus (MRS) isolation in dogs with naturally acquired bacterial keratitis.ProceduresAll Staphylococcus spp. isolated from corneal samples of dogs with keratitis during a 2-year period were evaluated for methicillin resistance by bacteriologic methods. Each MRS isolate was subjected to in vitro susceptibility testing for systemic and ocular antimicrobials. Nasal swabs for culture were collected from all dogs with MRS corneal isolation to evaluate for nasal carrier status. Potential risk factors for MRS isolation were investigated by medical record review and administration of an epidemiological survey to dog owners. Collected information characterizing animal, client, and environmental variables was analyzed for association with MRS isolation.ResultsSeventy-one Staphylococcus spp. were isolated from seventy individual dogs with keratitis during the study period. Seventeen of the Staphylococcus isolates (23.9%) were methicillin resistant. The MRS isolates included Staphylococcus epidermidis (n=10), Staphylococcus pseudintermedius (n=6), and Staphylococcus aureus (n=1). The MRS corneal isolates displayed extensive antimicrobial resistance. Four dogs (23.5%) with MRS corneal isolates had positive nasal cultures for MRS. Client occupation was significantly (P=0.01) associated with MRS isolation, and dogs belonging to owners employed in veterinary or human healthcare fields were four times more likely to have MRS keratitis than dogs owned by clients with different professions. There were no significant associations between the other evaluated animal, client, and environmental factors.ConclusionsMethicillin resistance is relatively common in Staphylococcus isolates from dogs with corneal infections, particularly among dogs belonging to healthcare workers.Objective To describe in vivo corneal confocal microscopy of dogs during the clinical course of fungal keratitis and correlate findings with clinical evaluations and an ex vivo experimental canine fungal keratitis model.Animals Studied Seven dogs with naturally acquired fungal keratitis and ex vivo canine corneas experimentally infected with clinical fungal isolates.Procedures Dogs with naturally acquired fungal keratitis were examined by in vivo laser scanning confocal microscopy. Initial confocal microscopic examinations were performed to assist in establishing the diagnosis of fungal keratitis. Serial confocal microscopic examinations were performed to guide antifungal chemotherapy. Confocal microscopy images of canine corneal fungal isolates were obtained by examination of experimentally infected ex vivo canine corneas to corroborate in vivo findings.Results Fungi cultured and detected by PCR from canine corneal samples included Candida albicans, Fusarium incarnatum-equiseti, Malassezia pachydermatis, and a Rhodotorula sp. Linear, branching, interlocking, hyperreflective structures were detected by confocal microscopy in dogs with filamentous fungal keratitis and round to oval hyperreflective structures were detected in dogs with yeast fungal keratitis. Antifungal chemotherapy was associated with a progressive reduction in the distribution and density of corneal fungal elements, alterations to fungal morphology, decreased leukocyte numbers, restoration of epithelial layers, and an increased number of visible keratocyte nuclei. No dogs had a recurrence of fungal keratitis following medication discontinuation. Confocal microscopic fungal morphologies were similar between in vivo and ex vivo examinations.Conclusions In vivo corneal confocal microscopy is a rapid method of diagnosing fungal keratitis in dogs and provides a noninvasive mechanism for monitoring therapeutic response.