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

The Korea INfectious Diseases (KIND) study group

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish
Pages (from-to)67-74
Number of pages8
JournalEuropean Journal of Clinical Microbiology and Infectious Diseases
Volume38
Issue number1
DOIs
Publication statusPublished - 2019 Jan 22

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Methicillin
beta-Lactams
Staphylococcus aureus
Anti-Bacterial Agents
meropenem
Ceftriaxone
Mars
Lactams
General Hospitals
sultamicillin
tazobactam drug combination piperacillin
Genes

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)
  • Infectious Diseases

Cite this

@article{d0c4f09b23ba44a3b3d1ea84d9f1e077,
title = "Inoculum effect of methicillin-susceptible Staphylococcus aureus against broad-spectrum beta-lactam antibiotics",
abstract = "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.",
author = "{The Korea INfectious Diseases (KIND) study group} and Song, {Kyoung Ho} and Jung, {Sook In} and Shinwon Lee and Sohee Park and Kim, {Eu Suk} and Park, {Kyung Hwa} and Park, {Wan Beom} and Choe, {Pyoeng Gyun} and YoungKeun Kim and Kwak, {Yee Gyung} and Kim, {Yeon Sook} and Jang, {Hee Chang} and Sungmin Kiem and Kim, {Hye In} and Kim, {Hong Bin}",
year = "2019",
month = "1",
day = "22",
doi = "10.1007/s10096-018-3392-6",
language = "English",
volume = "38",
pages = "67--74",
journal = "European Journal of Clinical Microbiology and Infectious Diseases",
issn = "0934-9723",
publisher = "Springer Verlag",
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}

Inoculum effect of methicillin-susceptible Staphylococcus aureus against broad-spectrum beta-lactam antibiotics. / The Korea INfectious Diseases (KIND) study group.

In: European Journal of Clinical Microbiology and Infectious Diseases, Vol. 38, No. 1, 22.01.2019, p. 67-74.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Inoculum effect of methicillin-susceptible Staphylococcus aureus against broad-spectrum beta-lactam antibiotics

AU - The Korea INfectious Diseases (KIND) study group

AU - Song, Kyoung Ho

AU - Jung, Sook In

AU - Lee, Shinwon

AU - Park, Sohee

AU - Kim, Eu Suk

AU - Park, Kyung Hwa

AU - Park, Wan Beom

AU - Choe, Pyoeng Gyun

AU - Kim, YoungKeun

AU - Kwak, Yee Gyung

AU - Kim, Yeon Sook

AU - Jang, Hee Chang

AU - Kiem, Sungmin

AU - Kim, Hye In

AU - Kim, Hong Bin

PY - 2019/1/22

Y1 - 2019/1/22

N2 - 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.

AB - 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.

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JO - European Journal of Clinical Microbiology and Infectious Diseases

JF - European Journal of Clinical Microbiology and Infectious Diseases

SN - 0934-9723

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