The bla content of the JPH203 cost isolates analyzed had been determined in a past study [3]. Thirty seven (88%) of the 42 aac(6’)-lb-cr were borne on integrons containing the ISCR1 VRT752271 ic50 while 55% were borne on integrons linked to the IS26. Twenty four (71%) of the 34 isolates carrying a qnrA gene were resistant to nalidixic acid but not to ciprofloxacin while the other 10 isolates carrying this gene and 19 carrying the qnrB subtype were resistant to both antimicrobials,

Table 8. None of the isolates tested positive for qnrS. Majority (87%) of qnr genes were physically linked to either integron-associated ISCR1 or the IS26. All Isolates carrying aac(6’)-lb-cr YH25448 cell line or the qnr genes contained multiple genetic elements and were all MDR. Table 8 Carriage of aac(6′)-lb-cr and qnr genes among strains containing genetic elements and bla genes     Number (%) of strains carrying each gene and number (%) of strains containing genes linked to genetic elements Occurrence in strains carryingblagenesa   Total Strains containingintI1 Linked tointI1 Strains containing IS26 Linked to IS26 Strains containing ISCR1 Linked to ISCR1 Strains containing ISEcp1 Linked to ISEcp1 β-lactamase negative strains Strains containing TEM-1 or SHV-1 only Strains containing broad-spectrumblagenes aac(6’)-lb-cr

42 42 (100) 42 (100) 6 (14) 4 (9) 12 (29) 6 (14) 11

(26) 4 (10) 0 4 (9) 38 (91) qnrA 34 27 (79) 26 (75) 11 (32) 4 (12) 28 (82) 23 (68) 8 (24) 1 (3) 0 2 (6) 32 (94) qnrB 19 19 (100) 11 (58) 10 (53) 2 (11) 13 (64) 4 (21) 12 (63) 1 (5) 0 1 (5) 18 (95) Table shows the number of isolates carrying the three (fluoro)quinolone resistance genes and the proportion of such strains in which these genes were physically linked to various genetic elements and to bla genes. a: Distribution of the aac(6’)-lb-cr and qnr genes among strains fully susceptible to β-lactams, among those resistant to TEM-1 or SHV-1 Tyrosine-protein kinase BLK with a narrow substrate-range and among those carrying genes encoding broad-spectrum β-lactamases such as bla SHV-5, bla SHV-12, bla CMY and bla CTX-Ms . Conjugative plasmids mediate en bloc transfer of multiple elements and resistance genes Multiple resistance genes and genetic elements associated with them were transferred en bloc to E. coli J53 in mating experiments, Table 9 . Majority of such transferred were mediated by plasmids containing I1, L/M, XI, HI2 and the F-type replicons. These experiments further revealed that genes conferring resistance to tetracylines and chloramphenicol were also harbored in the same plasmids encoding resistance to β-lactams, (fluoro)quinolones and aminoglycosides.