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Panel:   Enterobacterales Carbapenem Breakpoint (BIT)
AR Bank # 0024 Citrobacter koseri
Study ID: BIT-24

Biosample Accession #: SAMN04014865

MLST: Unknown

MICs obtained by broth microdilution. Modal MIC is reported.

MIC results for each antimicrobial agent for an isolate may commonly be ± 1 log2 (doubling dilution) different than what is posted on the FDA & CDC AR Bank website because this is the normal technical variability of antimicrobial susceptibility testing (see J. H. Jorgensen. 1993. J Clin Microbiol. Vol 31[11]: 2841-2844).

Panel:  Enterobacterales Carbapenem Breakpoint (BIT)  |  Piperacillin-tazobactam +aminoglycosides for Enterobacterales (PTA) (Custom)

MIC (μg/ml) Results and Interpretation
Drug MIC (μg/ml) INT
Amikacin <=1S
Ampicillin >32R
Ampicillin/sulbactam 1 62S
Aztreonam <=2S
Aztreonam/avibactam 1<=0.03---
Cefazolin 2S
Cefepime <=0.5S
Cefepime/zidebactam 2<=0.03---
Cefotaxime <=1S
Cefoxitin 4S
Ceftazidime <=1S
Ceftazidime/avibactam 1<=0.5S
Ceftolozane/tazobactam 1<=0.5S
Ceftriaxone <=1S
Ciprofloxacin <=0.25S
Colistin 51I
Doripenem <=0.12S
Eravacycline 30.06---
Ertapenem <=0.12S
Gentamicin 0.5S
Imipenem <=0.5S
Imipenem+chelators 4<=0.25---
Levofloxacin <=0.25S
Meropenem <=0.12S
Meropenem-vaborbactam 1<=0.5S
Minocycline <=4S
Nitrofurantoin 32S
Piperacillin/tazobactam 1<=4S
Tetracycline <=2S
Tigecycline 30.5S
Tobramycin 0.5S
Trimethoprim/sulfamethoxazole 10.5S
S – I –R Interpretation (INT) derived from CLSI 2022 M100 S32

1 Reflects MIC of first component
2 Cefepime to zidebactam ratio (1:1)
3 Based on FDA break points
4 Screen for metallo-beta-lactamase production [Rasheed et al. Emerging Infectious Diseases. 2013. 19(6):870-878]
5 Clinical and PK/PD data demonstrate colistin has limited clinical efficacy, even if an intermediate result is obtained. Alternative agents are strongly preferred. Colistin should be used in combination with one or more active antimicrobial agents. Consultation with an infectious disease specialist is recommended.
6 The MIC Interpretation has been defaulted to "Resistant" due to known intrinsic resistance for this bacterial species in the wild-type population. [See Appendix B, Intrinsic Resistance; CLSI M100]
Molecular Mechanisms of Resistance
Beta-lactam MAL-1
AR gene prediction was performed using ARG-ANNOT, ResFinder and NCBI (ResGANNCBI) databases accessed on 2021-05-07. AR drug classes are assigned according to these databases. This analysis does not include mutations that may result in antibiotic resistance or resistance determinants added to newer versions of used database or other antimicrobial resistance gene databases. For resistance determinant detection, 99-100% sequence identity and 100% sequence coverage from GAMMA and SRST2 was used. GAMMA uses amino acid sequence to assign gene alleles from assemblies; SRST2 uses nucleotide sequence to assign gene alleles from sequencing reads. Biosample accession numbers have been provided so that users can analyze the data on their own if so desired. *Presence of Efflux Pump may not be associated with resistance. *MLST Type (and scheme), as determined by Torsten Seemann's MLST program. For Enterobacterales, the Pasteur MLST schemes are used except for E. coli for which both the Pasteur and Achtman schemes are reported. SUB=novel MLST identified and "submitted".
Medium: Trypticase Soy Agar with 5% Sheep Blood (BAP)

Temperature: 35°C
Atmosphere: Aerobic


Remove the sample vial to a container with dry ice or a freezer block. Keep vial on ice or block. (Do not let vial content thaw)

Open vial aseptically to avoid contamination

Using a sterile loop, remove a small amount of frozen isolate from the top of the vial

Aseptically transfer the loop to BAP

Use streak plate method to isolate single colonies

Incubate inverted plate at 35°C ± 2°C for 18-24 hrs.

Storage Temperature & Biosafety

Appropriate safety procedures should always be used with this material. Laboratory safety is discussed in the current publication of 'BioSafety in Microbiological and Biomedical Laboratories' from the U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, and National Institutes of Health.

This product is sent with the condition that you are responsible for its safe storage, handling, and use. All materials are the property of the Centers for Disease Control and Prevention (CDC) and have been made available on behalf of the Food and Drug Administration (FDA). This material is not for use in human subjects and may not be redistributed. While CDC uses reasonable efforts to include accurate and up-to-date information on this product sheet, CDC makes no warranties or representations as to its accuracy. CDC is not liable for damages arising from the misidentification or misrepresentation of cultures. Please refer to the Standard Letter Agreement (SLA) for further details regarding the use of this product.
Isolate History
Date Action Performed
05/19/23MIC was updated with a new value for Amikacin: from <=4 to <=1
05/18/23MIC was updated with a new value for Aztreonam/avibactam: from --- to <=0.03
05/18/23Drug was added: Aztreonam/avibactam
02/16/23Interpretation was updated with a new value for Nitrofurantoin: from --- to S
02/16/23Interpretation was updated with a new value for Minocycline: from --- to S
02/16/23MIC was updated with a new value for Nitrofurantoin: from --- to 32
02/16/23MIC was updated with a new value for Minocycline: from --- to <=4
02/16/23Drug was added: Nitrofurantoin
02/16/23Drug was added: Minocycline
02/16/23MIC was updated with a new value for Amikacin: from 4 to <=4
10/25/22Interpretation was updated with a new value for Ceftazidime/avibactam: from --- to S
10/25/22MIC was updated with a new value for Ceftazidime/avibactam: from --- to =0.5
10/25/22Drug was added: Ceftazidime/avibactam
09/22/20MIC was updated with a new value
05/26/20MIC was updated with a new value
05/26/20Drug was added
03/12/20MIC was updated with a new value
03/12/20Drug was added
03/06/20MIC was updated with a new value
06/12/19MIC was updated with a new value
06/12/19Drug was added
05/22/19Isolate Characteristics was changed
05/22/19MIC was updated with a new value
05/22/19Drug was added
05/22/19CarbaNP changed
05/22/19mCIM changed
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