Ceftriaxone resistance of nontyphoidal Salmonella enterica isolates in Northern Taiwan attributable to production of CTX-M-14 and CMY-2 beta-lactamases.
Among 3,027 nontyphoidal Salmonella enterica isolates identified between January 1999 and December 2002 in a medical center in northern Taiwan, 31 were resistant to the extended-spectrum cephalosporin ceftriaxone (1.02% [31/3,027]), including 2 in 1999 (0.36% [2/549]), 13 in 2000 (1.49% [13/870]), 7 in 2001 (0.78% [7/893]), and 9 in 2002 (1.26% [9/715]). Sixteen of these isolates belonged to Salmonella serogroup B, nine belonged to serogroup C, four belonged to serogroup D, and two belonged to serogroup E. The majority were from stool cultures. The mechanism of resistance was investigated for eight isolates, including three S. enterica serovar Typhimurium, one S. enterica serovar Wagenia, one S. enterica serovar Senftenberg, one S. enterica serovar Derby, one S. enterica serovar Panama, and one S. enterica serovar Duesseldorf isolate. All eight patients from whom these isolates were recovered had community-acquired infections. All eight isolates were resistant to ampicillin, ceftriaxone, and cefotaxime but susceptible to imipenem and ciprofloxacin. Ceftriaxone resistance was due to the production of the CMY-2 AmpC beta-lactamase by seven isolates and the CTX-M-14 beta-lactamase by the remaining isolate. Both beta-lactamase genes were carried on conjugative plasmids. In a 2.5-kb region encompassing the bla(CMY-2) gene, at nucleotide 49 upstream of the start codon of bla(CMY-2), three of the seven bla(CMY-2)-positive isolates had an A nucleotide and four had a G nucleotide. In conclusion, the ceftriaxone resistance of nontyphoidal Salmonella isolates in our hospital was attributed to the CTX-M-14 and CMY-2 beta-lactamases.
Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan.
Wen-Chen
WC
Li
Fu-Yuan
FY
Huang
Chang-Pan
CP
Liu
Li-Chuan
LC
Weng
Nai-Yu
NY
Wang
Nan-Chang
NC
Chiu
Chuen-Sheue
CS
Chiang
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002443:Ceftriaxone / Q000494:pharmacology*; D018550:Cephalosporin Resistance; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D012480:Salmonella Infections / Q000382:microbiology; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D012703:Serotyping; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D002443:Ceftriaxone; C103022:beta-lactamase CMY-2; C456080:beta-lactamase CTX-M-14; D001618:beta-Lactamases