Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data

<i>Background and objectives:</i> For proper antimicrobial therapy, cumulative antibiograms should be representative of geographic region and be accurate. Clinical and Laboratory Standards Institute (CLSI) guidelines recommend that only the first isolates (FI) of a species per patient ar...

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Main Authors: Sollip Kim, Soo Jin Yoo, Jeonghyun Chang
Format: Article
Language:English
Published: MDPI AG 2020-09-01
Series:Medicina
Subjects:
Online Access:https://www.mdpi.com/1010-660X/56/10/507
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author Sollip Kim
Soo Jin Yoo
Jeonghyun Chang
author_facet Sollip Kim
Soo Jin Yoo
Jeonghyun Chang
author_sort Sollip Kim
collection DOAJ
description <i>Background and objectives:</i> For proper antimicrobial therapy, cumulative antibiograms should be representative of geographic region and be accurate. Clinical and Laboratory Standards Institute (CLSI) guidelines recommend that only the first isolates (FI) of a species per patient are used when reporting cumulative antibiograms. However, >50% of hospitals in the United States report antibiograms of all isolates. We compared antibiograms from the FI with those from total isolates (TI). <i>Materials and Methods:</i> Antimicrobial data of all isolates identified in the Microbiology unit of Ilsan Paik Hospital in 2019 were retrospectively acquired from the hospital information system. The susceptibility rates to antimicrobials of <i>Escherichia coli</i>, <i>Acinetobacter baumannii</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i>, <i>Staphylococcus aureus</i>, <i>Enterococcus faecium</i>, and <i>Enterococcus faecalis</i> were analyzed by FI and TI, respectively. Isolate counts and susceptibility rates of each species for the reported antimicrobials were compared. <i>Results:</i> The numbers of isolates by FI/TI were as follows: 1824/2692 <i>E. coli</i>, 480/1611 <i>A. baumannii</i>, and 662/1306 <i>K. pneumoniae</i>, and 407/953 <i>P. aeruginosa</i> for gram-negative bacteria and 649/1364 <i>S. aureus</i>, 211/313 <i>E. faecium</i>, and 323/394 <i>E. faecalis</i> for gram-positive bacteria. All antimicrobial agents showed higher susceptibility rates when calculated as FI than as TI in gram-negative bacteria except colistin: 3.7% for <i>E. coli</i>, 14.5% for <i>A. baumannii</i>, 8.3% for <i>K. pneumoniae</i>, and 7.9% for <i>P. aeruginosa</i>. In <i>S. aureus</i>, 8/11 antimicrobial agents revealed higher susceptibility rates for FI than for TI. <i>E. faecalis</i> and <i>E. faecium</i> showed lower susceptibility rates for 7/10 antimicrobial agents for FI than for TI. The oxacillin susceptibility rates of <i>S. aureus</i> were 36.6%/30.2% with FI/TI and vancomycin susceptibility rates for <i>E. faecium</i> were 54.1% and 49.5%, respectively. <i>Conclusions:</i> When comparing cumulative antibiograms by FI with TI using real-world data, there is a large gap for critical species requiring hospital infection control. Although FI calculation is difficult, antibiograms must be calculated as FI for proper preemptive antimicrobial therapy because FI provides proper antimicrobial susceptibility data.
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spelling doaj.art-89dbf3a0f6b14cf887c987b297193db52023-09-02T05:32:46ZengMDPI AGMedicina1010-660X2020-09-015650750710.3390/medicina56100507Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World DataSollip Kim0Soo Jin Yoo1Jeonghyun Chang2Laboratory Medicine, Inje University, Ilsan Paik Hospital, Goyang 10380, KoreaLaboratory Medicine, Inje University, Sanggye Paik Hospital, Seoul 10757, KoreaLaboratory Medicine, Inje University, Ilsan Paik Hospital, Goyang 10380, Korea<i>Background and objectives:</i> For proper antimicrobial therapy, cumulative antibiograms should be representative of geographic region and be accurate. Clinical and Laboratory Standards Institute (CLSI) guidelines recommend that only the first isolates (FI) of a species per patient are used when reporting cumulative antibiograms. However, >50% of hospitals in the United States report antibiograms of all isolates. We compared antibiograms from the FI with those from total isolates (TI). <i>Materials and Methods:</i> Antimicrobial data of all isolates identified in the Microbiology unit of Ilsan Paik Hospital in 2019 were retrospectively acquired from the hospital information system. The susceptibility rates to antimicrobials of <i>Escherichia coli</i>, <i>Acinetobacter baumannii</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i>, <i>Staphylococcus aureus</i>, <i>Enterococcus faecium</i>, and <i>Enterococcus faecalis</i> were analyzed by FI and TI, respectively. Isolate counts and susceptibility rates of each species for the reported antimicrobials were compared. <i>Results:</i> The numbers of isolates by FI/TI were as follows: 1824/2692 <i>E. coli</i>, 480/1611 <i>A. baumannii</i>, and 662/1306 <i>K. pneumoniae</i>, and 407/953 <i>P. aeruginosa</i> for gram-negative bacteria and 649/1364 <i>S. aureus</i>, 211/313 <i>E. faecium</i>, and 323/394 <i>E. faecalis</i> for gram-positive bacteria. All antimicrobial agents showed higher susceptibility rates when calculated as FI than as TI in gram-negative bacteria except colistin: 3.7% for <i>E. coli</i>, 14.5% for <i>A. baumannii</i>, 8.3% for <i>K. pneumoniae</i>, and 7.9% for <i>P. aeruginosa</i>. In <i>S. aureus</i>, 8/11 antimicrobial agents revealed higher susceptibility rates for FI than for TI. <i>E. faecalis</i> and <i>E. faecium</i> showed lower susceptibility rates for 7/10 antimicrobial agents for FI than for TI. The oxacillin susceptibility rates of <i>S. aureus</i> were 36.6%/30.2% with FI/TI and vancomycin susceptibility rates for <i>E. faecium</i> were 54.1% and 49.5%, respectively. <i>Conclusions:</i> When comparing cumulative antibiograms by FI with TI using real-world data, there is a large gap for critical species requiring hospital infection control. Although FI calculation is difficult, antibiograms must be calculated as FI for proper preemptive antimicrobial therapy because FI provides proper antimicrobial susceptibility data.https://www.mdpi.com/1010-660X/56/10/507cumulative antibiogramsusceptibilityfirst isolateempirical therapyantimicrobial agent
spellingShingle Sollip Kim
Soo Jin Yoo
Jeonghyun Chang
Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data
Medicina
cumulative antibiogram
susceptibility
first isolate
empirical therapy
antimicrobial agent
title Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data
title_full Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data
title_fullStr Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data
title_full_unstemmed Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data
title_short Importance of Susceptibility Rate of ‘the First’ Isolate: Evidence of Real-World Data
title_sort importance of susceptibility rate of the first isolate evidence of real world data
topic cumulative antibiogram
susceptibility
first isolate
empirical therapy
antimicrobial agent
url https://www.mdpi.com/1010-660X/56/10/507
work_keys_str_mv AT sollipkim importanceofsusceptibilityrateofthefirstisolateevidenceofrealworlddata
AT soojinyoo importanceofsusceptibilityrateofthefirstisolateevidenceofrealworlddata
AT jeonghyunchang importanceofsusceptibilityrateofthefirstisolateevidenceofrealworlddata