A new semi-selective medium for the isolation of Xanthomonas axonopodis pv. dieffenbachiae, the etiological agent of anthurium bacterial blight.
OBJECTIVE
Xanthomonas axonopodis pv. dieffenbachiae causes anthurium blight, which is regarded as the most threatening disease for the anthurium industry worldwide. The bacterium is listed as a quarantine pathogen in several regions, including Europe. We evaluated the use of Neomycin-Cephalexin-Trimethoprime-pirMecillinam 4 (NCTM4) medium for its isolation.


RESULTS
A total of 104 bacterial strains were inoculated onto NCTM4 and on the previously published Cellobiose-Starch (CS) and Esculin-Trehalose (ET) media. The strain collection included: the anthurium blight pathogen, Xanthomonas strains, for which false positive results are known to occur using serological identification-tests; other bacterial pathogens of anthurium; and representatives of bacteria that are commonly present in the anthurium phyllosphere. Media were evaluated following the ISO 16140 protocol for the validation of alternative methods.


CONCLUSIONS
Growth of the anthurium blight pathogen was better on NCTM4 and ET media than on CS. NCTM4 provided a better repeatability. It also displayed a lower rate of false positive and false negative results when the pathogen was isolated from plant extracts.


CONCLUSIONS
This study will lead to improved isolation protocols of the anthurium blight in official procedures. NCTM4 medium could also favourably be used in studies, which aim to further understanding of the biology and epidemiology of this pathogen.
Laurent
P
P
CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical CIRAD-Université de la Réunion, Pôle de Protection des Plantes, Saint Pierre, Réunion Island, France.
Chabirand
A
A
Jouen
E
E
Robène-Soustrade
I
I
Gagnevin
L
L
Hostachy
B
B
Pruvost
O
O
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D029064:Araceae / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry*; D003951:Diagnostic Errors; D024881:Drug Resistance, Bacterial; D005060:Europe; D010935:Plant Diseases / Q000382:microbiology*; D015203:Reproducibility of Results; D012641:Selection, Genetic; D012680:Sensitivity and Specificity; D053532:Xanthomonas axonopodis / Q000187:drug effects / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D003470:Culture Media