Abstract
Purpose :
During preparation of amniotic membrane (AM) in tissue banking fresh, non-preserved tissue and decontaminated preserved tissue were routinely screened for microbiological contamination. We performed a retrospective study to compare the results of microbial screenings of fresh AM and the corresponding decontaminated and cryopreserved tissue from placentas acquired at our local the cornea bank in order to evaluate the rate of contamination and the effectiveness of the decontamination procedures.
Methods :
Tissue samples from 55 processed placentae were tested for microbial contamination before and after decontamination with antibiotics and cryopreservation in glycerol and antibiotic containing medium at -80°C. Microbial growth was assessed by examining tissue samples in an automated test system. In case of detected microbial growth the contaminating species were identified.
Results :
In 22 out of the 55 examined placentae contamination of the non-decontaminated tissue by microorganisms was detected. The most prominent microorganismen was Propionibacterium acnes (8), followed by Staphylococcus epidermidis (6). The other microorganisms were detected in one placenta each: Propionibacterium avidum, Staphylococcus sacharolyticus, Staphylococcus lugdunensis, Bacillus spec., Faklamia hominis, Penicillium spec. and a non-specified aerobic sporulating bacterium. One sample showed contamination with two microorganisms. The corresponding decontaminated and cryopreserved tissue samples were void of microbial contamination. In four placentae contamination of the decontaminated tissue was detected. The microorganisms detected in these samples were Staphylococcus epidermidis, Bacillus simplex, Bacillus Pumilus and Propionibacterium acnes. There was no correlation between the contaminations of the non-decontaminated and corresponding decontaminated tissues.
Conclusions :
Despite handling and preparation of the amniotic tissue under sterile conditions it still showed contamination by microorganisms. The applied decontamination process seems to be effective since most of the examined tissue samples did not show contamination after the application of antibiosis. . The contaminations of the processed AM might be due to sporulating microorganism, which survive the decontamination (Bacillus spec.) or secondary contamination of the tissue due to inappropriate handling during the test procedure.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.