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  • Prevalence and antimicrobial susceptibilities of anaerobic bacteria isolated from perforated corneal ulcers by culture and multiplex PCR: an evaluation in cases with keratitis and endophthalmitis.

Prevalence and antimicrobial susceptibilities of anaerobic bacteria isolated from perforated corneal ulcers by culture and multiplex PCR: an evaluation in cases with keratitis and endophthalmitis.

Clinical laboratory (2015-02-05)
Hrisi Bahar Tokman, Güzin İskeleli, Zeynep Güngördü Dalar, Achille Aime Kangaba, Mehmet Demirci, Hatice K Akay, Bariş Ata Borsa, Reyhan Çalişkan Algingil, Bekir S Kocazeybek, Müzeyyen Mamal Torun, Nuri Kiraz
ABSTRACT

Anaerobic bacteria play an important role in eye infections; however, there is limited epidemiologic data based on the the role of these bacteria in the etiology of keratitis and endophthalmitis. The aim of this re- search is to determine the prevalence of anaerobic bacteria in perforated corneal ulcers of patients with keratitis and endophthalmitis and to evaluate their antimicrobial susceptibilities. Corneal scrapings were taken by the ophthalmologist using sterile needles. For the isolation of anaerobic bacteria, samples were inoculated on specific media and were incubated under anaerobic conditions obtained with Anaero-Gen (Oxoid & Mitsubishi Gas Company) in anaerobic jars (Oxoid USA, Inc. Columbia, MD, USA). The molecular identification of anaerobic bacteria was performed by multiplex PCR and the susceptibilities of an- aerobic bacteria to penicillin, chloramphenicol, and clindamycin were determined with the E test (bioMerieux). 51 strains of anaerobic bacteria belonging to four different genuses were detected by multiplex PCR and only 46 strains were isolated by culture. All of them were found susceptible to chloramphenicol whereas penicillin resistance was found in 13.3% of P.anaerobius strains, clindamycin resistance was found in 34.8% of P.acnes and 13.3% of P. anaerobius strains. Additionnaly, one strain of P. granulosum was found resistant to clindamycin, one strain of B. fragilis and one strain of P.melaninogenica were found resistant to penicillin and clindamycin. Routine analyses of anaerobes in perforated corneal ulcers is inevitable and usage of appropriate molecular methods, for the detection of bacteria responsible from severe infections which might not be deter- mined by cultivation, may serve for the early decision of the appropriate treatment. Taking into account the in- creasing antimicrobial resistance of anaerobic bacteria, alternative eye specific antibiotics effective against anaer- obes are needed to achieve a successful treatment.

MATERIALS
Product Number
Brand
Product Description

Supelco
Phylloquinone (K1), analytical standard
USP
Phytonadione, United States Pharmacopeia (USP) Reference Standard
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Chloramphenicol, VETRANAL®, analytical standard
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Phenylethyl Alcohol, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Phytonadione, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Phenethyl alcohol, ≥99%, FCC, FG
Sigma-Aldrich
Phenethyl alcohol, natural, ≥99%, FCC, FG
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Vitamin K1, BioXtra, ≥99.0% (sum of isomers, HPLC), mixture of isomers
Sigma-Aldrich
Vitamin K1, viscous liquid
Sigma-Aldrich
Chloramphenicol, meets USP testing specifications
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Chloramphenicol, BioReagent, suitable for plant cell culture
Sigma-Aldrich
Chloramphenicol, ≥98% (HPLC)
Phytomenadione, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
2-Phenylethanol, ≥99.0% (GC)
Chloramphenicol, European Pharmacopoeia (EP) Reference Standard