Identification by MALDI-TOF MS and Antibiotic Resistance of <i>Riemerella anatipestifer</i>, Isolated from a Clinical Case in Commercial Broiler Chickens

• Main Authors: Athina Tzora, Stylianos Skoufos, Eleftherios Bonos, Konstantina Fotou, Achilleas Karamoutsios, Aikaterini Nelli, Ilias Giannenas, Anastasios Tsinas, Ioannis Skoufos
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Veterinary Sciences
• Subjects: <i>Riemerella anatipestifer</i>; broiler chickens; MALDI-TOF; antibiotic resistance; clinical disease; bacteria
• Online Access: https://www.mdpi.com/2306-7381/8/2/29

The Gram-negative bacterium <i>Riemerella anatipestifer </i>(RA) is known to cause clinical disease with severe economic impacts primarily in ducks and less frequently in geese and turkeys. RA was isolated and identified in broiler chickens, from a clinical case in a commercial broiler farm located in the southwest mainland of Greece. The morbidity and the mortality in the broiler house were estimated at 10% and 5% respectively. The observed clinical signs appeared at the age of 30 to 42 days with respiratory distress (dyspnea), white fluid feces and stunting. Post-mortem examinations displayed serositis, pericarditis, perihepatitis and airsacculitis. Edematous swelling around the tibio-tarsal joints was observed in some birds. Tissue samples from lesions were streaked on selective media. Three bacterial isolates were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Moreover, an antibiogram analysis was performed for the three RA strains, using a pattern of 16 common antibiotics to advocate the most effective drugs for a proper treatment. All the RA isolates were sensitive to ceftiofur, sulphamethoxazole–trimethoprim and amoxicillin, whereas all were resistant to gentamicin, tylosin, tetracyclin, colistin sulphate, spectinomycin, lincomycin and oxytetracycline.