COMPARISON OF CLASSICAL INCUBATING METHODS ON SELECTIVE AGAR MEDIA AND MOLECULAR METHODS OF POLYMERASE CHAIN REACTION FOR ANALYSIS OF ARTIFICIALLY CONTAMINATED TEXTILES

Izhodišča: Kljub napredku na področju javnega zdravja in bolnišnične oskrbe, so bolnišnične okužbe pri hospitaliziranih bolnikih zelo pogost pojav. Izvor bolnišničnih okužb so lahko obiskovalci, zdravstveno osebje, bolniki, bolnikova okolica s kontaminiranimi predmeti in površinami. Eden izmed vektorjev prenosa mikroorganizmov in s tem bolnišničnih okužb so lahko tudi kontaminirane tekstilije, ki jih uporabljajo hospitalizirani bolniki (brisače, odeje, rjuhe, osebna oblačila). S postopki detekcije in identifikacije mikroorganizmov na tekstilijah lahko ocenimo stopnjo kakovosti higiene bolnišničnih tekstilij. To je zadosten razlog za iskanje optimalnih rešitev detekcije in identifikacije mikroorganizmov, ki morajo biti hitre, dostopne in cenovno ugodne. Metodologija: V raziskavi smo tekstilne krpice iz 100 % bombaža umetno kontaminirali z Gram-pozitivnima bakterijama E. faecium in S. aureus ter Gram-negativno bakterijo E. coli. Tekstilne krpice, kontaminirane z mikroorganizmi smo hranili 21 dni pri 5 ˚C, 25 ˚C in 50 ˚C. Vzorčili smo z aparatom Morapex A z nedestruktivno metodo eluiranja. V raziskavi smo ugotavljali, kako izpostavljenost bakterij daljšemu sušenju vpliva na preživetje le-teh in kako začetna koncentracija izbranih bakterij vpliva na delež preživelih bakterij glede na čas. Primerjali smo učinkovitost klasičnih gojitvenih metod na selektivnih agarnih gojiščih in učinkovitost molekularnih metod verižne reakcije s polimerazo pri identifikaciji izbranih vzorcev. Rezultati: Raziskava je pokazala, da je molekularna metoda na osnovi verižne reakcije s polimerazo občutljivejša metoda identifikacije DNA. Ugotovili smo, da izpostavljenost bakterij na umetno kontaminiranih tekstilijah daljšemu sušenju vpliva na preživetje bakterij ter da se število preživelih bakterij s časom zmanjšuje. Različne koncentracije izbranih bakterij na umetno kontaminiranih tekstilijah vplivajo na delež preživelih bakterij v času. Sklep: V raziskavi smo pokazali preživetje mikroorganizmov na tekstilijah pri različnih pogojih (čas, temperatura in koncentracija) pri čemer se je PCR metoda pokazala kot bolj občutljiva metoda identifikacije.Introduction: In spite of the progress made in the field of public health and hospital treatment, hospital infections are still a common occurrence among hospitalized patients. Visitors, hospital personnel, patients and the patients’ surroundings with contaminated objects and surfaces can be a source of hospital infections. Contaminated hospital textiles (towels, blankets, sheets, personal clothes) can be one the vectors of transmission of microorganisms and thus hospital infections. With detection and identification of microorganisms we can evaluate the hospital’s quality level considering hospital textile that can transmit microorganisms and cause hospital infections. This is reason enough to search for optimal, quick, affordable and low-cost solutions of microorganism detection and identification. Methodology: We artificially contaminated a textile made of 100 % cotton with the E. faecium and S. aureus Gram-positive and the E. coli Gram-negative bacteria. Textile swatches with microorganisms were stored at 5 ˚C, 25 ˚C and 50 ˚C for 21 days. During our research we took samples by applying a non-destructive method of elution with the Morapex A. We established the influence of a longer exposure of bacteria to drying on the survival of these bacteria and the influence of initial concentrations of the chosen bacteria on the proportion of the surviving bacteria in the course of time. We identified microorganisms with a classical incubating method almost every day. We also compared the efficiency of classical incubating methods on selective agar media with molecular methods of polymerase chain reaction with identification of chosen samples. Results: The research showed that the polymerase chain reaction-based molecular method is a more sensitive and precise DNA identification method. During our research we also determined that the exposure of bacteria on artificially contaminated textiles to longer drying periods affects the survival of these bacteria and that their number decreases with time of exposure. Different concentrations of the chosen bacteria on artificially contaminated textiles also determine the share of preserved bacteria in the course of time. Conclusion: In this study, we showed survival of microorganisms to textiles under various conditions (time, temperature and concentration). However, the most sensitive proved to be detection using PCR method