Gharamah Abdullah A, Moharram Ahmed M, Ismail Mady A, Al-Hussaini Ashraf K
School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Pinang, Malaysia.
Indian J Ophthalmol. 2014 Feb;62(2):196-203. doi: 10.4103/0301-4738.116463.
This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents.
One hundred and fifteen patients clinically diagnosed to have microbial keratitis were investigated. From these cases, 37 bacterial isolates and 25 fungal isolates were screened for their ability to produce extra-cellular enzymes in solid media. In addition, the ability of fungal isolates to produce mycotoxins and their sensitivity to 4 antifungal agents were tested.
Protease, lipase, hemolysins, urease, phosphatase, and catalase were detected respectively in 48.65%, 37.84%, 59.46%, 43.24%, 67.57%, and 100% out of 37 bacterial isolates tested. Out of 25 fungal isolates tested during the present study, 80% were positive for protease, 84% for lipase and urease, 28% for blood hemolysis, and 100% for phosphatase and catalase enzymes. Thirteen fungal isolates were able to produce detectable amounts of 7 mycotoxins in culture medium (aflatoxins (B1, B2, G1, and G2), sterigmatocystin, fumagillin, diacetoxyscirpenol, zearalenone, T-2 toxin, and trichodermin). Among the antifungal agents tested in this study, terbinafine showed the highest effect against most isolates in vitro.
In conclusion, the ability of bacterial and fungal isolates to produce extracellular enzymes and toxins may be aid in the invasion and destruction of eye tissues, which, in turn, lead to vision loss.
开展本研究以探讨上埃及地区角膜炎病例中分离出的细菌和真菌产生酶、毒素的能力，并检测分离出的真菌种类对某些治疗药物的敏感性。
对115例临床诊断为微生物性角膜炎的患者进行了调查。从这些病例中，筛选了37株细菌分离株和25株真菌分离株在固体培养基中产生细胞外酶的能力。此外，还检测了真菌分离株产生霉菌毒素的能力及其对4种抗真菌药物的敏感性。
在所检测的37株细菌分离株中，分别有48.65%、37.84%、59.46%、43.24%、67.57%和100%检测到蛋白酶、脂肪酶、溶血素、脲酶、磷酸酶和过氧化氢酶。在本研究检测的25株真菌分离株中，80%的菌株蛋白酶呈阳性，84%的菌株脂肪酶和脲酶呈阳性，28%的菌株有血液溶血现象，100%的菌株磷酸酶和过氧化氢酶呈阳性。13株真菌分离株能够在培养基中产生可检测量的7种霉菌毒素（黄曲霉毒素（B1、B2、G1和G2）、杂色曲霉素、烟曲霉毒素、二醋酸藨草镰刀菌烯醇、玉米赤霉烯酮、T-2毒素和木霉菌素）。在本研究中测试的抗真菌药物中，特比萘芬在体外对大多数分离株显示出最高的效果。
总之，细菌和真菌分离株产生细胞外酶和毒素的能力可能有助于眼部组织的侵袭和破坏，进而导致视力丧失。
