The cefazolin inoculum effect in methicillin-susceptible Staphylococcus aureus blood isolates: their association with dysfunctional accessory gene regulator (agr).
We evaluated the clinical significance of the cefazolin inoculum effect (CIE) in methicillin-susceptible Staphylococcus aureus (MSSA) isolates. In total, 146 isolates were recovered from patients with MSSA bacteremia at 9 hospitals in Korea. The CIE was observed in 16 MSSA isolates, and while type A was the only detected β-lactamase in MSSA isolates exhibiting the CIE, no strains expressing type B, C, or D β-lactamases exhibited this effect. The CIE was only observed in agr group III and I isolates and was significantly more common in isolates with agr dysfunction than in those with functional agr (P<0.001). Even among isolates producing type A β-lactamase, the CIE was also prevalent in isolates with dysfunctional agr than in isolates with functional agr (P=0.025). This study demonstrates an association between the CIE of MSSA isolates and agr dysfunction, in addition to those between the CIE and type A β-lactamase.
Division of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea; Department of Medicine, The Graduate School of Yonsei University, Seoul, Republic of Korea.
Yu Mi
YM
Wi
Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.
Young Kyoung
YK
Park
Division of Infectious Diseases, Inje University Busan Paik Hospital, Busan, Republic of Korea.
Chisook
C
Moon
Division of Infectious Diseases, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea.
Seong Yeol
SY
Ryu
Division of Infectious Diseases, Dong-A University, Busan, Republic of Korea.
Hyuck
H
Lee
Division of Infectious Diseases, Konkuk University Hospital, Seoul, Republic of Korea.
Hyun Kyun
HK
Ki
Division of Infectious Diseases, Konkuk University Hospital, Seoul, Republic of Korea.
Hae Suk
HS
Cheong
Division of Infectious Diseases, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea.
Jun Seong
JS
Son
Division of Infectious Diseases, Kangdong Sacred Heart Hospital, Hallym University School of Medicine, Seoul, Republic of Korea.
Jin Seo
JS
Lee
Division of Infectious Diseases, Daegu Fatima Hospital, Daegu, Republic of Korea.
Ki Tae
KT
Kwon
Department of Medicine, The Graduate School of Yonsei University, Seoul, Republic of Korea.
June Myong
JM
Kim
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Young Eun
YE
Ha
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Cheol In
CI
Kang
Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea. Electronic address: ksko@skku.edu.
Kwan Soo
KS
Ko
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: iddrchung@gmail.com.
Doo Ryeon
DR
Chung
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Kyong Ran
KR
Peck
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Jae-Hoon
JH
Song
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology; D001426:Bacterial Proteins; D002437:Cefazolin / Q000494:pharmacology*; D004361:Drug Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D056910:Republic of Korea; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D015534:Trans-Activators / Q000172:deficiency*; D001618:beta-Lactamases / Q000145:classification / Q000378:metabolism*
C095698:Agr protein, Staphylococcus aureus; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015534:Trans-Activators; D001618:beta-Lactamases; D002437:Cefazolin
Accessory gene regulator; Cefazolin; Inoculum effect; Methicillin-susceptible S. aureus