Impact of Siderophore Genes on Cefiderocol Susceptibility in Carbapenem Resistant Hypervirulent Klebsiella Pneumoniae

Condition(s) studied

Investigational drug(s) / intervention(s)

Cefiderocol susceptibility testing: Determination of cefiderocol susceptibility in carbapenem-resistant hypervirulent Klebsiella pneumoniae isolates using antimicrobial susceptibility testing according to CLSI guidelines.

Study summary

1. Sample: Clinical specimens (blood, urine, sputum, wound swabs) will be collected aseptically and transported to the microbiology laboratory for analysis.
2. Culture: Specimens will be inoculated on MacConkey agar and incubated at 35-37°C for 18-24 hours. Colonies with typical K. pneumoniae morphology (mucoid, lactose-fermenting) will be selected for further testing
3. Identification of isolates will be done by:

Colony morphology, Gram staining, and conventional biochemical tests (eg, indole, citrate utilization, urease, Voges-Proskauer) .
4. Antimicrobial susceptibility testing of the isolates :

Antimicrobial susceptibility testing was performed and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines, M100 document (latest edition)."
5. MIC determination for cifederecol using E-test .
6. Phenotypic Detection of hvKP:

1. String Test: A viscous string ≥5 mm formed by stretching a single colony indicates hypermucoviscosity .
2. Capsule Staining: to visualize large capsules .
3. Siderophore Production: Assessed on chrome azurol S (CAS) agar to detect iron-chelating activity.
7. Detection of siderophore genes by Simple qualitative PCR .

Eligibility

Primary outcome measure(s)

• Proportion of cefiderocol-susceptible CR-hvKP isolates (%) — 6 months

Trial sites (1)

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