The IntIPstQ-like integrase recombination sites (attC sites) are poorly associated to attCs from antimicrobial resistance gene cassettes of class 1 integrons

ALONSO FM; GAMBINO AS; ÁLVAREZ VE; QUIROGA MP; CENTRÓN D

Ciudad Autónoma de Buenos Aires

Congreso; Segunda Reunión Conjunta de Sociedades de Biociencias; 2017

SAIC-SAIB-SAI-SAA-SAB-SAB-SAFE-SAFIS-SAH-SAP

The gram negative bacillus Pseudomonas stutzeri is an integron carrier, naturally competent andan opportunistic pathogen widely distributed in the environment. Such characteristicsmake P. stutzeri a promising organismfor the study of lateral genetic transfer (LGT) mechanisms. In order to study the diversity of the attC recombination sites associated withIntIPstQ-like and its contribution tomultidrug resistant integrons we performed a search for sequences with anidentity >65% with IntIPstQintegrase. Sequences were analyzed with INTEGRON FINDER to detect: C-In (completeintegrons, Integrase+attC), CALINs (clusters of attC sites lackingintegron-integrases) and In0(Integrase only). Sequence and phylogenetic analysis of IntIPstQ were made to establish its relationship with otherintegron integrases. We also carried out a phylogenetic analysis of the obtainedattC sites and the ones of the mainantibiotic resistance gene cassettes (ARGC). Twenty sequences belonging to Pseudomonas, Halothiobacillus, Azotobacter,Methylibium,Thioalkalivibrio were analyzed and 15 C-In, 25 CALINs and 4 In0 wereidentified. A total of 285 attC siteswere found, 170 located in C-In (59,65%) and 115 in CALINs (40,35%). The length of attC sites was variable between 42 and 132bp, being the mostfrequent of 76bp. IntIPstQ ismore likely to be related to IntI2. The tetrad RHRY was conserved in most cases and 50% ofthe strains showed an ALAR motif, which seems to be involved in the interaction with the gene cassettes.Changes in the physicochemical naturecould cause alterations and preferences in its catalytic activity. Most attC sites from ARGCs were found in 3 main subclusters related to attCs from Halothiobacillus sp., Azotobacterand Methylibium. Only attCqnrVC1 was foundamong attC sites from Pseudomonas. Taken together, our resultssuggest that the genus Pseudomonas isnot an active reservoir of attC sitesthat circulate by the mechanisms of the LGT in multidrug resistant isolates.