Publikationsdatenbank

Hygiene in ophthalmic surgery and bacterial resistancy on the ocular surface of animals (2018)

Art

Hochschulschrift

Autor

Soimala, Tanawan (WE 20)

Quelle

Berlin: Mensch und Buch Verlag Berlin, 2018 — 97 Seiten

ISBN: 978-3-86387-919-8

Sprache

Englisch

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/24953

Kontakt

Klein- und Heimtierklinik

Oertzenweg 19 b
14163 Berlin
+49 30 838 62422
kleintierklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Ocular infections in animals can be result in blindness. The infections are most caused by bacteria particular microbiota from the patient’s conjunctiva, eyelid, and nose. When damage to ocular tissue occurs, opportunistic bacteria may invade ocular tissues causing infection that may be difficult to treat, especially if the bacteria are antibiotic resistant like MRSA. Therefore, the usage of antibiotics has to be carefully monitored to prevent antibiotic resistance and a global reduction in a use of antibiotics a practical aim. Povidone-Iodine (PI) is generally known for being effective against bacteria, fungi, viruses, and protozoa. Moreover, an ideal solution as it is inexpensive, and no irritation is caused when diluted below 1%. One study indicated that Neosporin eye drops and PI administration before ophthalmic surgery caused similar decreases in the number of colonies and species cultured. Therefore, PI can be offered as an alternative to antibiotics. Forty eyes: (24 dogs and 16 cats) were divided into four groups of ten according to the concentrations of PI 0.1%, 0.2%, 1% and 5%. Seventy-four eyes (48 dogs and 8 cats) were included for assessment of the antimicrobial activity of 0.2% PI. Conjunctival swabs were collected from 44 horses (46 eyes) to determine the occurrence of MRSA on the ocular surface of the horse. In the first study, ocular swabs were collected before aseptic preparation (t0), after aseptic preparation (t1) and after surgery (t2). Tissue reaction was monitored at t1. Specimens were analyzed for cultivable aerobic and anaerobic bacteria and fungi. Positive culture swabs were used to measure the effectiveness of PI. In the second study, the conjunctival swabs that were collected before ophthalmic surgery were immediately processed with testing of colonies suspected to be S. aureus was carried out using Vitek2 system (bioMérieux, Lyon) and the presence of MRSA was verified by PCR. Genetic relatedness of all MRSA isolates was investigated by pulsed-field gel electrophoresis (PFGE) and spa-typing. The result of the first study indicated that 0.2% and 1% PI solutions could be used to eliminate bacterial contamination of ocular surface tissue without tissue reaction. However, 0.2% PI proven to be more effective than more concentrated solutions (p= 0.02). Additionally, 0.2% PI concentration significantly reduced Bacillus sp. and coagulase negative Staphylococcus sp. at t1 and t2. MRSA was not positive in our first study. That is why the effectiveness of PI on eliminating MRSA on the ocular surface of animals still undetermined. The results of the second study indicated that the isolation rates of MRSA on the ocular surface of horses were high (13%) 6/46 samples. Molecular typing revealed that all detected MRSA were the spa-type t011. This type is commonly associated with the European livestockassociated MRSA lineage of the clonal complex CC 398 that recently emerged in horses in Germany. Additionally, PFGE revealed that the six MRSA had a very closely related relationship (>90%). According to the history of the patients and the result of the microbiological examination, it can be suggested that this phenomenon was a nosocomial infection. MRSA reported in our study exhibited further resistance towards antibiotics frequently used for topical eye treatment, e.g. fluoroquinolones, tetracycline's, kanamycin and gentamicin. The most effective concentration of PI was proven to be 0.2%. It demonstrated excellent antibacterial activity against Bacillus sp. and coagulase-negative Staphylococcus sp. This study demonstrated a high prevalence of MRSA on the ocular surfaces of equine ophthalmic patients supporting the need for constant bacterial surveillance. More studies are needed on the source of MRSA in equine ophthalmic patients including an environmental factor, standard operation procedures (SOPs), manipulations and diagnostic approaches. The evaluation of the bactericidal activity of antiseptic agents against MRSA on the ocular surface of animals at either higher concentrations of PI or alternative protocols and active components to reduce ocular surface contamination are still needed.