Colistin susceptibility testing and Vitek-2™: is it really useless?

Girardello, Raquel; Cury, Arlete Emily; Franco, Maria Renata Gomes; Gioia, Thais Romano Di; Almeida, João Nóbrega de; Araújo, Maria; Duarte, Alberto José da Silva; Rossi, Flávia

doi:10.1016/j.diagmicrobio.2018.03.019

Cited by 19 publications

(14 citation statements)

References 3 publications

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“…However, the clonally related isolates were all from this hospital, and the isolates from other hospitals were unrelated. Some colistin-resistant isolates may have been missed, as only isolates shown to be resistant using Vitek were collected, and the limitations of the Vitek for colistin susceptibility testing have been described (Girardello et al, 2018). Likewise, colistinsusceptible isolates belonging to the same clone may have been missed, since the primary selection criterion was colistin resistance and the neonatal isolates were included fortuitously.…”

Section: Limitationsmentioning

confidence: 99%

Clonal expansion of colistin-resistant Acinetobacter baumannii isolates in Cape Town, South Africa

Snyman

Whitelaw

Reuter

et al. 2020

International Journal of Infectious Diseases

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To describe colistin-resistant Acinetobacter baumannii isolates in Cape Town, South Africa. Methods: A. baumannii isolates identified on Vitek 2 Advanced Expert System were collected from Tygerberg Hospital referral laboratory between 2016 and 2017. Colistin resistance was confirmed using broth microdilution and SensiTest. mcr-1-5 were detected using PCR and strain typing was performed by rep-PCR. Whole genome sequencing (WGS) was performed on a subset of isolates to identify chromosomal colistin resistance mechanisms and strain diversity using multilocus sequence typing (MLST) and pairwise single nucleotide polymorphism analyses. Results: Twenty-six colistin-resistant and six colistin-susceptible A. baumannii were collected separately based on Vitek susceptibility; 20/26 (77%) were confirmed colistin-resistant by broth microdilution. Four colistin-resistant isolates were isolated in 2016 and 16 in 2017, from five healthcare facilities. Thirteen colistin-resistant isolates and eight colistin-susceptible isolates were identical by rep-PCR and MLST (ST1), all from patients admitted to a tertiary hospital during 2017. The remaining colistin-resistant isolates were unrelated. Conclusions: An increase in colistin-resistant A. baumannii isolates from a tertiary hospital in 2017 appears to be clonal expansion of an emerging colistin-resistant strain. This strain was not detected in 2016 or from other hospitals. Identical colistin-susceptible isolates were also isolated, suggesting relatively recent acquisition of colistin resistance.

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Section: Limitationsmentioning

confidence: 99%

Clonal expansion of colistin-resistant Acinetobacter baumannii isolates in Cape Town, South Africa

Snyman

Whitelaw

Reuter

et al. 2020

International Journal of Infectious Diseases

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“…Moreover, for K. pneumoniae and E. coli, the Vitek-2 provided better performance for isolates with MIC ≤ 0.5 and ≥ 16 µg/ mL than the isolates with MIC within > 0.5 and < 16 µg/mL. These results were presented by Girardello et al 26 that compared performance of Vitek-2 with BMD in determination of colistin susceptibility. The authors 26 reported a good correlation of results between Vitek-2 and BMD when tested K. pneumoniae and E. coli with isolates of MICs ≤ 0.5 and ≥ 16 µg/mL.…”

Section: Discussionmentioning

confidence: 62%

“…These results were presented by Girardello et al 26 that compared performance of Vitek-2 with BMD in determination of colistin susceptibility. The authors 26 reported a good correlation of results between Vitek-2 and BMD when tested K. pneumoniae and E. coli with isolates of MICs ≤ 0.5 and ≥ 16 µg/mL. In addition, the Vitek-2 was able to detect the resistance of 10 isolates of mcr-1-carrying E. coli although this polymyxin resistance mechanism exhibited borderline MICs of 4 µg/mL [6 isolates] and 8 µg/mL [4 isolates].…”

Section: Discussionmentioning

confidence: 74%

“…In addition, the Vitek-2 was able to detect the resistance of 10 isolates of mcr-1-carrying E. coli although this polymyxin resistance mechanism exhibited borderline MICs of 4 µg/mL [6 isolates] and 8 µg/mL [4 isolates]. Therefore, Girardello et al suggested that susceptibility testing with the reference method (broth microdilution) might be unnecessary when Vitek-2-determined MICs were either very low (≤ 0.5 µg/mL) or very high (≥ 16 µg/mL) 26 .…”

Section: Discussionmentioning

confidence: 99%

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Efficacy of loading dose colistin versus carbapenems for treatment of extended spectrum beta lactamase producing Enterobacteriaceae

Katip

Yoodee

Uitrakul

et al. 2021

Sci Rep

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Colistin provides in vitro activity against numerous ESBL-producing and carbapenem-resistant bacteria. However, clinical information with respect to its utilization in infection caused by ESBL producers is limited. The aim of this study was a comparison of mortality rates of loading dose (LD) colistin and carbapenems as definitive therapies in a cohort of patients with infections caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae. A retrospective cohort study in 396 patients with ESBL-producing E.coli and K.pneumoniae infection at a university-affiliated hospital was conducted between 1 January 2005 and 30 June 2015 to compare outcomes of infected patients who received LD colistin (95 patients) with carbapenems (301 patients). The three primary outcomes were 30-day mortality, clinical response and microbiological response. The most common infection types were urinary tract infection (49.49%), followed by pneumonia (40.66%), bacteremia (13.64%), skin and soft tissue infections (4.80%) and intra-abdominal infection (3.03%). LD colistin group provided higher 30-day mortality when compared with carbapenems group (HR 7.97; 95% CI 3.68 to 17.25; P = 0.001). LD colistin was also independently associated with clinical failure (HR 4.30; 95% CI 1.93 to 9.57; P = 0.001) and bacteriological failure (HR 9.49; 95% CI 3.76 to 23.96; P = 0.001) when compared with those who received carbapenems. LD colistin treatment was associated with poorer outcomes, i.e. mortality rate, clinical response and microbiological response. Moreover, when adjusted confounding factors, LD colistin was still less effective than carbapenems. It should be noted that, however, the use of Vitek-2 to assess colistin susceptibility could provide inaccurate results. Also, the difference in baseline characteristics could still remain in retrospective study although compensation by hazard ratio adjustment was performed. Therefore, clinical utilization of LD colistin should be recommended as an alternative for treatment ESBL-producing Enterobacteriaceae only in the circumstances where carbapenems cannot be utilized, but this recommendation must be considered carefully.

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“…Bunun ana nedeni, büyük molekül ağırlığına sahip olan kolistinin agara difüzyonunun zor olması, bu durumun disk difüzyon ve gradiyent test yöntemlerinin performansını düşürmesidir 1 . Yapılan çalışmalarda, yarı-otomatize sistemlerin performanslarının da kolistin direncini saptamada yeterli olmadığı gösterilmiştir 4,5 . 2017 yılında "Clinical and Laboratory Standards Institute (CLSI)" ve "European Committee on Antimicrobial Susceptibility Testing (EUCAST)" ortak çalışma grubu, kolistin duyarlılığının belirlenmesinde polistren mikroplak ve kolistin sülfat tuzu kullanımını, referans yöntem olarak ise "International Organization for Standardization (ISO)" standart sıvı mikrodilüsyon yöntemine (SMD) (20776-1) göre çalışılmasını önermiştir 6,7 .…”

Section: Mi̇krobi̇yoloji̇ Bülteni̇unclassified

Klebsiella pneumoniae İzolatlarında Sıvı Mikrodilüsyon Temelli İki Ticari Sistemin Referans Mikrodilüsyon Yöntemine Göre Değerlendirilmesi

Kansak¹,

Aslan²,

Adaleti³

et al. 2020

Mikrobiyol Bul

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Colistin susceptibility testing and Vitek-2™: is it really useless?

Cited by 19 publications

References 3 publications

Clonal expansion of colistin-resistant Acinetobacter baumannii isolates in Cape Town, South Africa

Clonal expansion of colistin-resistant Acinetobacter baumannii isolates in Cape Town, South Africa

Efficacy of loading dose colistin versus carbapenems for treatment of extended spectrum beta lactamase producing Enterobacteriaceae

Klebsiella pneumoniae İzolatlarında Sıvı Mikrodilüsyon Temelli İki Ticari Sistemin Referans Mikrodilüsyon Yöntemine Göre Değerlendirilmesi

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