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. 2018 Feb 20;17(1):5.
doi: 10.1186/s12941-018-0257-x.

Continued in vitro cefazolin susceptibility in methicillin-susceptible Staphylococcus aureus

Benjamin H Gern  1 , Alexander L Greninger  2 , Scott J Weissman  1 , Jennifer R Stapp  3 , Yue Tao  4 , Xuan Qin  5   6   7
Affiliations

Continued in vitro cefazolin susceptibility in methicillin-susceptible Staphylococcus aureus

Benjamin H Gern et al. Ann Clin Microbiol Antimicrob. .

Abstract

Objectives: In vitro trends of cefazolin and ceftriaxone susceptibilities from pediatric clinical isolates of methicillin-susceptible Staphylococcus aureus (MSSA) between 2011 and 2016 were analyzed for surveillance.

Methods: Our laboratory continues to use agar disk diffusion for staphylococcal susceptibilities applying Clinical Laboratory Standard Institute's 2012 breakpoints.

Results: A total of 3992 MSSA clinical isolates in the last 6 years were analyzed for their in vitro cefazolin and ceftriaxone susceptibilities. While all MSSA isolates exhibited cefazolin susceptibilities within the "susceptible" zone range, there have been a proportion of isolates with ceftriaxone susceptibilities falling in "intermediate" zones, ranging from 2.6% in 2011 to 8.3% in 2016.

Conclusions: Cefazolin continues to be the recommended agent for MSSA treatment at our institution, reflected by the finding that only 2% (6/321) of patients who received ceftriaxone as definitive therapy for MSSA bacteremia during the study period. We have confirmed the cefoxitin-predicted MSSA susceptibility to cefazolin, but have found concerning drifts in ceftriaxone susceptibilities by continued in vitro monitoring over the last 6 years.

Keywords: Cefazolin; Ceftriaxone; MIC; MSSA; Staphylococcus aureus.

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Figures

Fig. 1
Fig. 1
Ceftriaxone zone diameters (mm) for MSSA isolates, separated by year collected. Black bars are zone diameters in “Intermediate” range (14–20 mm), light gray bars are zone diameters in “Susceptible” range (≥ 21 mm). Values in top left corner of each pane reflect percent “intermediate” of all MSSA isolates to ceftriaxone in each year.  Values in top right corner of each pane reflect percent of S. aureus isolates that were methicillin susceptible (MSSA) in each year
Fig. 2
Fig. 2
Characteristic “Cliff” versus “Beach” inhibitory zones associated with cefazolin and ceftriaxone respectively by disk diffusion method against MSSA isolates
See this image and copyright information in PMC

References

    1. Kirby WM. Extraction of a highly potent penicillin inactivator from penicillin resistant Staphylococci. Science. 1944;99:452–453. doi: 10.1126/science.99.2579.452. - DOI - PubMed
    1. Barber M. Methicillin-resistant staphylococci. J Clin Pathol. 1961;14:385–393. doi: 10.1136/jcp.14.4.385. - DOI - PMC - PubMed
    1. Chang S, Sievert DM, Hageman JC, Boulton ML, Tenover FC, Downes FP, Shah S, Rudrik JT, Pupp GR, Brown WJ, Cardo D, Fridkin SK, Vancomycin-Resistant Staphylococcus aureus Investigative T Infection with vancomycin-resistant Staphylococcus aureus containing the vanA resistance gene. N Engl J Med. 2003;348:1342–1347. doi: 10.1056/NEJMoa025025. - DOI - PubMed
    1. Chambers HF. The changing epidemiology of Staphylococcus aureus? Emerg Infect Dis. 2001;7:178–182. doi: 10.3201/eid0702.010204. - DOI - PMC - PubMed
    1. CLSI . Performance standards for antimicrobial susceptibility testing. M100-S22. Wayne: Institute CaLS, Clinical and Laboratory Standards Institute; 2012.

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