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Can colistin susceptibility results determined in multidrug resistant Gram-negative bacteria be used for polymyxin B?

Open Access
|Nov 2023

Figures & Tables

MIC values (μg/ml) for colistin and polymyxin B in P_aeruginosa and A_ baumannii strains (n = 117)Grey font numbers indicate the number of strains with equivalent MICs for colistin and polymyxin B_

Colistin (mg/L)>=256 2A
128 1A
64 1P+1A
32 1A
16 1A 1P+1A
8 1P+2A1P2P
4 3A2P+2A2P+1A5P+1A1A
21A1P+5A10P+8A16P+9A3P
11A4A12P+4A1P+1A
0.51P+2A1P+2A
0.252P 1P
0.250.51248163264128>=256
Polymyxin B (mg/L)

MIC values (μg/ml) for colistin and polymyxin B in E_ coli and K_ pneumoniae bacteria (n = 151)Grey font numbers indicate the number of strains with equivalent MICs for colistin and polymyxin B

Colistin (mg/L)>=256 1K
128 1K2K1K
64 4K9K5K
32 3K12K8K1K
16 4K4K
8 1K+1E1K1K
4 1K+3E1K+8E1K+3E1K
22k2K5K+9E2K+7E2E
11k2K+2E2K+4E1K+9E5E
0.52k3K+2E1K2K+2E1E
<=0.253k+1E2K
0.250.51248163264128>=256
Polymyxin B (mg/L)

MIC values and interpretations of colistin and polymyxin B against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii strains

Bac.Col. MICInterp.Poly. MICInt.Bac.Col. MICInterp.Poly. MICInterp.Bac.Col. MICInt.Poly. MICInt.Bac.Col. MICInt.Poly. MICInt.Bac.Col. MICInt.Poly. MICInt.
E11I2IK11I1IK6464R64RP12I1IA14R0.5I
E21I4RK21I1IK6564R32RP24R1IA24R2I
E34R1IK31I2IK6664R32RP31I1IA38R1I
E42I1IK41I0.5IK6764R32RP41I1IA4256R128R
E51I2IK51I0.25IK6864R16RP52I1IA52I0.5I
E62I2IK61I0.5IK6964R32RP64R2IA64R4R
E71I4RK72I1IK7064R16RP72I4RA72I1I
E81I2IK82I1IK7164R32RP81I2IA80.5I0.5I
E91I2IK92I1IK72128R64RP91I1IA92I0.25I
E104R2IK102I0.5IK73128R64RP101I1IA102I2I
E111I1IK112I1IK74128R32RP111I1IA112I1I
E121I2IK122I0.25IK75128R128RP122I1IA1216R4R
E132I2IK132I0.25IK7632R16RP132I1IA132I2I
E141I2IK142I0.5IK770.25I0.5IP141I1IA140.5I0.5I
E150.5I2IK152I1IK780.25I0.5IP154R1IA152I1I
E160.5I2IK162I2IK790.25I0.25IP162I1IA162I1I
E171I1IK172I2IK800.25I0.25IP1716R16RA171I0.5I
E181I0.5IK184R8RK810.25I0.25IP182I1IA182I2I
E192I1IK194R1IK820.5I0.25IP192I2IA191I2I
E204R2IK204R4RK830.5I0.5IP201I1IA202I2I
E212I2IK214R2IK840.5I0.5IP211I1IA210.5I0.25I
E222I1IK228R2IK850.5I1IP221I1IA222I2I
E231I2IK238R8RK860.5I0.5IP231I1IA232I1I
E241I4RK248R4RK870.5I0.25IP248R2IA241I1I
E254R2IK2516R8RK880.5I2IP258R4RA251I1I
E262I4RK2616R16RK890.5I2IP268R4RA262I2I
E271I4RK2716R16RK9032R32RP272I0.5IA274R1I
E282I1IK2816R16RK91256R128RP282I2IA28256R128R
E298R2IK2916R8RK9216R8RP298R1IA2916R16R
E304R2IK3016R16R P302I1IA302I1I
E311I4RK3116R8R P312I1IA311I1I
E321I2IK3232R8R P321I1IA32128R64R
E332I2IK3332R16R P3364R64RA331I0.5I
E340.5I4RK3432R16R P341I1IA3432R32R
E354R4RK3532R64R P350.25I1IA352I1I
E361I1IK3632R32R P362I1IA3664R64R
E374R2IK3732R32R P372I2IA371I1I
E382I1IK3832R16R P382I1IA380.5I0.25I
E391I2IK3932R32R P390.5I0.5IA391I0.5I
E404R2IK4032R16R P402I2IA401I0.25I
E414R2IK4132R32R P410.25I0.25IA414R8R
E422I2IK4232R8R P420.25I0.25IA422I0.5I
E434R4RK4332R16R P430.5I0.25IA432I0.5I
E442I2IK4432R8R P444R2IA444R1I
E454R4RK4532R16R P454R4RA454R0.5I
E462I4RK4632R32R P462I4RA462I0.5I
E471I0.5IK4732R16R P472I2IA474R0.5S
E482I1IK4832R16R P482I2IA482I0.5I
E491I1IK4932R16R P492I2IA498R1I
E504R2IK5032R16R P502I2IA502I2I
E510.25I0.25IK5132R32R P512I2IA512I2I
E520.5I0.5IK5232R32R P524R4RA521I0.5I
E532I2IK5332R16R P534R4RA532I2I
E544R1IK5464R32R P542I2IA542I1I
E550.5I0.5IK5564R32R P554R4R
E562I1IK5664R16R P562I2I
E572I1IK5764R32R P572I2I
E582I1IK5864R16R P582I2I
E594R1IK5964R64R P592I2I
K6064R64R P602I2I
K6164R64R P612I2I
K6264R32R P622I4R
K6364R64R P634R4R

Differences in MIC values between colistin and polymyxin B among tested isolates

Organisms (n)Polymyxin B more potent by n (%) of strainsSame MICColistin more potent by n (%) of strains
3 dilution2 dilution1 dilutionn (%)1 dilution2 dilution3 dilution
E.coli (59)04 (6.8)19 (32.2)17 (28.8)11 (18.6)7 (11.9)1 (1.7)
K. pneumonia (92)2 (2.2)13 (14.1)39 (42.4)30 (32.6)6 (6.5)2 (2.2)0
P. aeruginosa (63)1 (1.6)4 (6.3)15 (23.8)38 (60.3)4 (6.3)1 (1.6)0
A. baumannii (54)6 (11.1)9 (16.7)18 (33.3)19 (35.2)2 (3.7)00
Total 2689 (3.4)30 (11.2)91 (34.0)104 (38.8)23 (8.6)10 (3.7)1 (0.4)

Colistin and polymyxin B evaluation criteria for Enterobacterales, P_ aeruginosa and A_ baumannii according to CLSI and EUCAST criteria

CLSI Susceptible (μg/mL)Intermediate(μg/mL)Resistant(μg/mL)
Colistin ≤2≥4
Polymyxin B ≤2≥4
EUCAST Susceptible (mg/L)Intermediate (mg/L)Resistant (mg/L)ECOFF (mg/L)
Colistin*≤2 ≥4
Colistin**≤4 ≥8
Polymyxin B* 2
Polymyxin B** 4

The essential agreement, categorical agreement rates of polymyxin B and resistance rates of colistin and polymyxin B in studied bacteria

ColistinPolymyxin B
BacteriaEA n (%)CA n (%)I n (%)R n (%)I n (%)R n (%)
E. coli47 (79.7)39 (66.1)44 (74.6)15 (25.4)48 (81.4)11 (18.6)
K. pneumoniae75 (81.5)89 (96.7)30 (32.6)62 (67.4)33 (35.9)59 (64.1)
P. aeruginosa57 (90.5)54 (85.7)48 (76.2)15 (23.8)51 (81.0)12(19.0)
A. baumannii39 (72.2)46 (85.2)37 (68.5)17 (31.5)45 (83.3)9 (16.7)
Total218 (81.3)228 (85.1)159 (59.3)109 (40.7)177 (66.0)91 (34.0)

Categorical agreement rates changing according to susceptibility status for colistin-polymyxin B intermediate–resistant isolates

StrainsColistinPolymyxin B% of Categorical agreement
Escherichia coli (I)443681.8
Escherichia coli(R)15320
Klebseilla pneumoniae(I)3030100
Klebseilla pneumoniae(R)625995.2
Escherichia coli+ Klebseilla pneumoniae(I)746689.2
Escherichia coli+ Klebseilla pneumoniae(R)776280.5
Pseudomonas aeruginoa(I)484593.8
Pseudomonas aeruginoa(R)15960
Acinetobacter baumannii(I)3737100
Acinetobacter baumannii (R)17952.9
Pseudomonas aeruginoa +Acinetobacter baumannii(I)858296.5
Pseudomonas aeruginoa +Acinetobacter baumannii(R)321856.3
Language: English
Page range: 125 - 132
Submitted on: Jan 31, 2023
Accepted on: Aug 17, 2023
Published on: Nov 14, 2023
Published by: Hirszfeld Institute of Immunology and Experimental Therapy
In partnership with: Paradigm Publishing Services
Publication frequency: 1 times per year

© 2023 Rıza Adaleti, Nilgün Kansak, Şeyma Çalık, Neslihan Arıcı, Seniha Şenbayrak, Sebahat Aksaray, published by Hirszfeld Institute of Immunology and Experimental Therapy
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.