A 5-yr retrospective study (November 2006-December 2011) was conducted to determine the isolation frequency of Pasteurella multocida and Gallibacterium anatis and their antibiograms from chickens submitted to the Mississippi Poultry Research and Diagnostic Laboratory. The number of isolations of G. anatis increased over the last 5 yr in broiler and broiler breeder type chickens. For P. multocida, the number of isolations increased from 2006 to 2010, but decreased through 2011 with all isolations being from boiler breeder type chickens. Gallibacterium anatis demonstrated almost complete resistance to novobiocin, tylosin, lincosamide, and tetracycline antimicrobials with moderate to high sensitivity to sulfonamides, fluoroquinolones, and florfenicol. There was intermediate sensitivity for spectinomycin and erythromycin and variable resistance to β-lactam and aminoglycoside antimicrobials. In sharp contrast, P. multocida showed moderate to high sensitivity to β-lactam, novobiocin, and tetracycline antimicrobials, but had antibiograms similar to G. anatis for the other antimicrobials. Sensitivities were determined using minimum inhibitory concentration. This study examines the trends over a 5-yr period of the number of isolates of P. multocida and G. anatis and their sensitivities. These 2 pathogens produce very similar clinical signs and lesions (fowl cholera-like) in breeders despite having extremely antagonistic sensitivity patterns. This study shows the necessity for producers to attempt culture and sensitivity in suspect fowl cholera-like flocks before initiating antimicrobial treatment commonly used with P. multocida for fear that the culprit may actually be the more antimicrobial-resistant G. anatis.

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Enterococcus cecorum has been associated mainly with osteomyelitis of the free thoracic vertebra in chickens. However, there are reports of E. cecorum producing septicemic lesions and having tropism for cartilages, resulting in the presentation of femoral head necrosis and synovitis. This paper discusses the presentation of E. cecorum as it relates to an outbreak in one vertical integrator where the main lesions were related to septicemia. Using a convenience sampling method, 100 broiler chicken cases received at the Poultry Research and Diagnostic Laboratory of Mississippi State University from April to December of 2021 were analyzed. The peak in cases was observed from June to August. The average age of broilers was 21 days with a range of 15-31 days. Most of these cases were related to systemic disease and leg problems, with gross lesions including characteristic pericarditis along with perihepatitis, osteomyelitis, and arthritis. In six of the 100 cases, E cecorum was isolated from the free thoracic vertebra, with the remaining being recovered from various other locations including liver, pericardium, hock/joint, femoral head, and bone marrow. Enterococcus cecorum identification was performed by using Vitek matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. These results were then sent to the research-use only SARAMIS database for analysis. Once the spectra of the isolates were imported, the relative and absolute taxonomy were analyzed. Two super spectrums and three clusters by homology were identified. The minimal inhibitory concentrations obtained by antimicrobial sensitivity tests were analyzed using WHONET Microbiology Laboratory Database Software. No isolates were pan-susceptible, 80% of isolates were noted to be resistant to 3 classes of antibiotics and, in general, isolates exhibited a high degree of variability when examining antimicrobial resistance patterns.RESUMEN. Reporte de caso-Caracterización de un brote reciente de Enterococcus cecorum causante de una enfermedad sistémica grave simulta ´neamente con problemas en las patas en un integrador de pollo de engorde en el sur de los Estados Unidos.La bacteria Enterococcus cecorum se ha asociado principalmente con osteomielitis de la vértebra tora ´cica móvil de los pollos. Sin embargo, existen reportes de E. cecorum produciendo lesiones septicémicas y presentando tropismo por los cartílagos, resultando en la presentación de necrosis de la cabeza femoral y sinovitis. Este artículo analiza la presentación de E. cecorum relacionada con un brote en un integrador vertical donde las principales lesiones estaban relacionadas con septicemia. Utilizando un método de muestreo de conveniencia, se analizaron 100 casos de