Comparison of Colony Forming Unit (CFU) Counts and Quantitative PCR (qPCR) Conidial Equivalent (CE) Measurement in a Murine Model of Fusariosis.

L. OSTROSKY-ZEICHNER, A. PHILIP, Z. ODABASI, V.L. PAETZNICK, J.R. RODRIGUEZ, E. CHEN, J.H. REX

Author address: 

Univ. of Texas-Houston Med. Sch., Houston, TX

Abstract: 

Introduction: Fusariosis is an emerging mycosis of increasing importance in the immunocompromised population. Animal models of this infection are required to explore new therapeutic options. Measurement of organ burden by qPCR is a novel way to evaluate the severity of infection. Methods: Male CF-1 mice were intravenously inoculated with 1.3x107 CFU of Fusarium solani FS-1184. Mice were observed for 10 days to evaluate survival by the Kaplan-Meier method. Five mice were sacrificed daily to measure CFU and CE by qPCR on the following equally-divided homogenized organs: Brain, kidneys, liver, and spleen. CFU/g of tissue were counted by plating serial dilutions of the organs on Sabouraud-dextrose plates. CE/g of tissue values were determined using DNA primers and a probe specific for F. solani 18S rDNA, and conidial standards spiked into naïve tissues. Results: Mean±SD of the log10 CFU/g and CE/g tissue at days 1, 3, 6 and 9 are presented in the table. Probability of survival at day 10 was 27%. Day Brain Kidneys Liver Spleen qPCR CFU qPCR CFU qPCR CFU qPCR CFU 1 4.71±0.40 3.16±0.15 4.52±0.41 4.25±0.18 5.25±0.14 4.43±0.10 3.00±0.85 3.75±0.42 3 5.51±0.68 4.13±0.41 4.70±0.29 4.01±0.12 5.21±0.21 4.43±0.17 4.22±0.84 3.79±0.28 6 3.60±0.47 3.28±0.26 5.19±0.81 4.20±0.55 4.71±0.13 3.77±0.24 3.01±0.29 0.57±1.28 9 4.24±0.30 2.91±0.49 5.89±0.49 4.55±0.18 4.49±0.18 1.52±2.14 2.52±0.32 0.00 Discussion: Higher CE/g tissue values across all tissues over time suggests qPCR is a more sensitive measure of F. solani burden in tissues than CFU. The infection progressed in kidneys but remained stable or appeared to decrease in other organs. Further evaluation of F. solani pathogenesis and response to antifungal therapy using qPCR is warranted.

2003

abstract No: 

M-362

Full conference title: 

43rd Interscience Conference on Antimicrobial Agents
    • ICAAC 43rd