TABLE 1.

Susceptibility patterns of DHA-1-producing K. pneumoniae isolatesa

IsolateExtended-spectrum β-lactamase confirmatory test (inhibition zone, mm)MIC (μg/ml)Disk diffusion test
CAZCAZ + CLAbCTXCTX + CLAbAMCPIPTZPFOXCAZCAZ+ CLAcCTXCTX + CLAcATMATM + CLAcCFPCFP + CLAcIPMIPM + CLAcGNTOBAMKOFXCIPSXT
38717121915>256>25616>256166441648<0.130.130.130.13SSSSSS
41621142317>256>25632>2568321424<0.13<0.130.250.25RRSSSS
149013112315>256>25632>256321284168320.250.50.130.13RRSRRR
159615122116>256>25632>2566425616648320.250.50.250.25RRSRRR
19716132316>256>25632>256166428832<0.13<0.130.50.5RSSRRR
27417132217>256>25632>256163224416<0.13<0.130.250.25RSSRRR
2811592522>256>25616>256321284168320.130.50.50.5RSSRRR
32522142417>256>2568>2564641818<0.13<0.130.250.25RSSSSS
39720122420>256>2568>2568321818<0.13<0.130.250.25RRSIIS
106721112623>256>2568>256864216216<0.13<0.130.50.5SSSIIS
  • a AMC, amoxacillin-clavulanic acid; AMK, amikacin; ATM, aztreonam; CAZ, ceftazidime; CFP, cefepime; CIP, ciprofloxacin; CLA, clavulanic acid; CTX, cefotaxime; FOX, cefoxitin; GN, gentamicin; IPM, imipenem; OFX, ofloxacin; PIP, piperacillin; SXT, trimethoprim-sulfamethoxazole; TOB, tobramycin; TZP, piperacillin-tazobactam; S, susceptible; I, intermediate susceptible; R, resistant.

  • b Clavulanic acid at a concentration of 10 μg/ml.

  • c Clavulanic acid at a fixed concentration of 2 μg/ml.