Figure 2

Schematic representation of different types of gene cassettes identified in the Class 1 integrons in A. baumannii strains. Dotted lines represent the gene cassettes, oval circles the 59-base elements. The att I recombination site is shown by the hatched box. Locations of the 5'CS and 3'CS of class 1 integrons and those of the primer pairs, qacEΔ1-F, Sul1B and in-F (5'CS), in-B (3'CS), are shown in the bottom panel. Different types of variable region were found in our collection of isolates: Type I: accC1-orfX-orfX'-aadA1; n = 3, Type II: aacA4-catB8-aadA1, n = 26, Type III: aadB-aadA2; n = 3 and Type IV: aadB; n = 1. accC1 (3-N-aminoglycoside acetyltransferase) and aadB (2'-O-adenylyltransferase) confers gentamicin resistance, aadA1 and aadA2 (adenyltransferase) confers resistance to spectinomycin and streptomycin, aacA4 (6'-N-acetyltransferase) confers resistance to amikacin, netilmicin and tobramycin, catB8 (chloramphenicol acetyltransferase) confers resistance to chloramphenicol. The diagram was not drawn to scale.