Inoculum effect of methicillin-susceptible Staphylococcus aureus against broad-spectrum beta-lactam antibiotics.

Autor: the Korea INfectious Diseases (KIND) study group, Song, Kyoung-Ho, Kim, Eu Suk, Kim, Hong Bin, Kim, Hye-In, Jung, Sook-In, Park, Kyung-Hwa, Lee, Shinwon, Park, Sohee, Park, Wan Beom, Choe, Pyoeng Gyun, Kim, Young Keun, Kwak, Yee Gyung, Kim, Yeon-Sook, Jang, Hee-Chang, Kiem, Sungmin
Předmět:
Zdroj: European Journal of Clinical Microbiology & Infectious Diseases; Jan2019, Vol. 38 Issue 1, p67-74, 8p
Abstrakt: Scarce information concerning the inoculum effect (InE) of methicillin-susceptible Staphylococcus aureus (MSSA) against broad-spectrum β-lactam antibiotics is available. We investigated the InE of MSSA against ceftriaxone, cefepime, meropenem, ampicillin/sulbactam and piperacillin/tazobactam. The bacteraemic MSSA isolates were collected at ten Korean general hospitals from Sep 2013 to Mar 2015. The InE was defined if MICs of antibiotics at high inoculum (HI, ~5 × 107 CFU/ml) increased beyond the susceptible range compared to those at standard inoculum (SI, ~5 × 105 CFU/ml). All isolates were sequenced for blaZ gene typing. Among 302 MSSA isolates, 254 (84.1%) were positive for blaZ; types A, B, C and D were 13.6%, 26.8%, 43.4% and 0.3%, respectively. Mean HI MICs of all tested antibiotics were significantly increased and increases in HI MIC of piperacillin/tazobactam (HI, 48.14 ± 4.08 vs. SI, 2.04 ± 0.08 mg/L, p < 0.001) and ampicillin/sulbactam (HI, 24.15 ± 1.27 vs. SI, 2.79 ± 0.11 mg/L, p < 0.001) were most prominent. No MSSA isolates exhibited meropenem InE, and few isolates exhibited cefepime (0.3%) and ceftriaxone (2.3%) InE, whereas 43.0% and 65.9% of MSSA isolates exhibited piperacillin/tazobactam and ampicillin/sulbactam InE, respectively. About 93% of type C blaZ versus 45% of non-type C exhibited ampicillin/sulbactam InE (p < 0.001) and 88% of type C blaZ versus 9% of non-type C exhibited piperacillin/tazobactam InE (p < 0.001). A large proportion of MSSA clinical isolates, especially those positive for type C blaZ, showed marked ampicillin/sulbactam InE and piperacillin/tazobactam. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
Externí odkaz: