Producción CyT
XVIII Congreso de la Sociedad Argentina de Microbiología General - Role of the accessory protein MobS in conjugation of a novel subfamily of MobQ mobilizable plasmids from Acinetobacter spp.
Congreso
Autoría:
ORTELLADO, VALENTIN IGNACIO ; Rey, Constanza ; Rocco-Welsh, Ramiro Eugenio ; Pistorio, Mariano ; Toscani, Andrés MartinFecha:
2023Editorial y Lugar de Edición:
XVIII Congreso de la Sociedad Argentina de Microbiología General: Libro de ResumenesResumen *
Acinetobacter baumanii is an opportunistic pathogen that has become relevant due to itscapacity to overcome extremely unfavorable environmental conditions and its tendency ofdeveloping antimicrobial multiresistance. The spreading of such capacities amongAcinetobacter and other nosocomial genera is a consequence of horizontal gene transfer.Plasmids are small self-replicating extra-chromosomal bacterial DNA molecules that serveas vehicles for propagation of genes capable of bringing adaptive advantages to its recipientcell. Plasmids interchange by conjugation is considered one of the main mechanisms ofhorizontal gene transfer among bacteria.Characterizing a plasmid collection obtained from nosocomial Acinetobacter isolates, ourgroup has described a novel subfamily within MOBQ plasmids. DNA transfer and replication(Dtr) genomic structure of such plasmids resembles pTF1 plasmid of Thiobacillusferrooxidans, an IncQ replicon composed by an accessory protein (MobS) and a relaxase(MobL). Plasmids from IncQ incompatibility group are broadly distributed and involved indispersion of antibiotic resistance.In previous work we analyzed the conjugative transfer capacity of two plasmids from thisMOBQ family: pIH6 and pIH7. Quantitative assessment of conjugative transference revealeda differential behavior of Dtrs from plasmid pIH6 regarding pIH7 when using IncP, IncN,IncW and IncX plasmids as helpers. In addition, bioinformatical analysis revealed that, whilethe N-terminus of mobL gene product is highly conserved among plasmids, the C-terminalend of such proteins and the accessory protein MobS are extremely variable. These resultssupport the idea that MobL C-terminal domain and/or MobS are playing part in the selectivityof the Dtr for a specific conjugative machinery.The aim of the present work is to functionally characterize this novel subfamily of MOBQplasmids. In particular, we aim to study the dependency of the accessory protein MobS onthe conjugative transference of this subfamily of MOBQ plasmids from Acinetobacter spp.Dtr regions excluding mobS gene from plasmids pIH6 and pIH7 (corresponding to mobLand oriT) were cloned in the non-mobilizable vector pK18 and transferred into Escherichiacoli DH5α carrying RN3 (IncN) and R751 (IncP) helper plasmids. Quantitative conjugationassays were performed using the Rifampicin-resistant E. coli strain HB101. We observedthat, while deletion of mobS from pIH7 Dtr dramatically decreased the number oftransconjugants when the RN3 helper plasmid was used, ablation of the accessory proteinfrom pIH6 only diminished the conjugation frequency in one order of magnitude when it ismoved by the R751 mobilization machinery.Our results showed a differential behavior of MobS when different Mpf systems areinvolved, suggesting that crosstalk between Dtr elements and Mpf determines the necessityof accessory proteins in conjugation of plasmids of this subfamily of MOBQ replicons fromAcinetobacter. Información suministrada por el agente en SIGEVAPalabras Clave
plasmidsconjugationantimicrobial multiresistanceMOBQaci