Karakterizacija sevov Escherichia spp., izoliranih iz gvana netopirjev iz Škocjanskih jam

Plaskan, Monika (avtor), Ambrožič Avguštin, Jerneja (mentor), Mulec, Janez (komentor)

V raziskavi smo analizirali 81 izolatov bakterij iz rodu Escherichia, ki so jih iz gvana netopirjev, vzorčenega v letih 2020 in 2021 v Škocjanskih jamah, izolirali na Inštitutu za raziskovanje krasa ZRC SAZU. Izolatom smo določili ERIC-profil, jih uvrstili v filogenetske skupine po prvotni in prenovljeni metodi, analizirali prisotnost genov, povezanih z dejavniki virulence in testirali občutljivost za izbrane protimikrobne učinkovine. Ugotovili smo, da je med 81-imi sevi 26 neklonalnih sevov vrste Escherichia coli, med katerimi jih je bilo največ uvrščenih v filogenetsko skupino B23 po prvotni, oziroma B2 po prenovljeni metodi po Clermontu. Med dejavniki virulence, ki se uvrščajo v skupino adhezinov, smo pri vseh izolatih bakterije E. coli potrdili gena crl in fimH, polovica izolatov je bila pozitivnih za avtotransporterski gen vat, med toksini in invazini smo največkrat potrdili gene astA, hlyF in usp. Najpogosteje zastopan gen za dejavnike, povezane z izogibanjem imunskemu sistemu, je bil gen traT, med geni, povezanimi s privzemom železa smo pri polovici izolatov potrdili gena fyuA in irp2. Fenotipsko smo odpornost proti vsaj eni protimikrobni učinkovini potrdili pri 21 neklonalnih izolatih vrste E. coli. Potrdili smo, da izolati vsebujejo tudi plazmide, a je bila njihova izolacija težavna. Za 17 sevov z enakim ERIC-profilom na podlagi zaporedja gena za 16S rRNA nismo mogli ločiti izolatov vrste E. coli od vrste E. marmotae, smo pa z MALDI-TOF MS potrdili, da izolati, ki na gojišču MacConkey tvorijo bele kolonije, pripadajo nedavno opisani vrsti E. marmotae. To je prvi primer izolacije bakterije E. marmotae iz gvana netopirjev.

• Jezik: Slovenski jezik
• Ključne besede: netopirji, kraške jame, gvano, E. coli, E. marmotae, dejavniki virulence, protimikrobne učinkovine
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: BF - Biotehniška fakulteta
• Kraj izida: Ljubljana
• Založnik: [M. Plaskan]
• Leto izida: 2022
• PID: 20.500.12556/RUL-140959
• UDK: 579.25:631.854:551.44
• COBISS.SI-ID: 122371843
• Datum objave v RUL: 22.09.2022

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Characterization of Escherichia spp. strains isolated from bat guano from Škocjan caves

Izvleček

In the present study, we analyzed 81 bacterial isolates of the genus Escherichia isolated from bat guano sampled in Škocjan caves at the Institute of Karst Research ZRC SAZU in 2020 and 2021. We determined the ERIC profile of the isolates, classified them into phylogenetic groups according to the original and revised methods, analyzed the presence of virulence factor genes, and tested their sensitivity to selected antimicrobial agents. We found that among the 81 isolates, 26 were nonclonal, belonging to Escherichia coli, most of which were classified into phylogenetic group B23 by the original method and into group B2 by the revised method after Clermont. Among genes for virulence factors associated with adhesions, we confirmed crl and fimH in all E. coli isolates, half of the isolates were positive for the autotransporter gene vat, and among toxins and invasins, we most frequently confirmed the astA, hlyF, and usp genes. The most frequent gene for factors related to immune defense was traT, and among genes related to iron uptake, fyuA and irp2 were confirmed in half of the isolates. Phenotypically, resistance to at least one antimicrobial agent was confirmed in 21 nonclonal E. coli isolates. We confirmed that the isolates also contained plasmids, but their isolation was difficult. For 17 strains with the same ERIC profile, we could not distinguish whether they belonged to E. coli or E. marmotae based on the 16S rRNA gene sequence. However, analysis by MALDI-TOF MS confirmed that the isolates forming white colonies on the MacConkey medium belong to the recently described species E. marmotae. This is the first report of isolation of E. marmotae from bat guano.

• Ključne besede: bats, karst caves, guano, E. coli, E. marmotae, virulent factors, antimicrobial agents