Emergence of CTX-M-15 type extended-spectrum β-lactamase-producing Salmonella spp. in Kuwait and the United Arab Emirates

Cephalosporins are major antimicrobials used to treat serious Salmonella infections. However, their effectiveness is being compromised by the emergence of extended-spectrum beta-lactamases (ESBLs). The genetic determinants encoding ESBL in Salmonella spp. isolated from patients in Kuwait and United Arab Emirates (UAE) were studied over a 2 year period. Out of a total of 407 isolates, 116 isolates possessed the resistance phenotypes consistent with possible ESBL production. Of these, 69 (59.5%) were ESBL positive. PCR and sequencing were used to determine the genetic determinant(s) responsible for ESBL phenotypes. A total of 14 (12.1%) and 29 (24.6%) isolates were CTX-M-15 ESBL producers and TEM producers, respectively. Ten CTX-M-15 producers carried the insertion sequence ISEcpl gene. PFGE analysis revealed identical profiles in 4 of the 13 Kuwaiti strains. This study reports the presence of the b/a(CTX-M-15) gene in Salmonella sop. and Salmonella enterica serotype Typhi from Kuwait and UAE for what is believed to be the first time. This is of great concern as the gene is also found in association with the ISEcpl gene, which may easily facilitate its spread. These isolates originated mostly from non-Kuwaiti Arabs rather than from people of Asian origin.