Review on skeletal disorders caused by Staphylococcus spp. in poultry

Abstract

Lameness or leg weakness is the main cause of poor poultry welfare and serious economic losses in meat-type poultry production worldwide. Disorders related to the legs are often associated with multifactorial aetiology which makes diagnosis and proper treatment difficult. Among the infectious agents, bacteria of genus Staphylococcus are one of the most common causes of bone infections in poultry and are some of the oldest bacterial infections described in poultry. Staphylococci readily infect bones and joints and are associated with bacterial chondronecrosis with osteomyelitis (BCO), spondylitis, arthritis, tendinitis, tenosynovitis, osteomyelitis, turkey osteomyelitis complex (TOC), bumblefoot, dyschondroplasia with osteomyelitis and amyloid arthropathy. Overall, 61 staphylococcal species have been described so far, and 56% of them (34/61) have been isolated from clinical cases in poultry. Although Staphylococcus aureus is the principal cause of poultry staphylococcosis, other Staphylococcus species, such as S. agnetis, S. cohnii, S. epidermidis, S. hyicus, S. simulans, have also been isolated from skeletal lesions. Antimicrobial treatment of staphylococcosis is usually ineffective due to the location and type of lesion, as well as the possible occurrence of multidrug-resistant strains. Increasing demand for antibiotic-free farming has contributed to the use of alternatives to antibiotics. Other prevention methods, such as better management strategies, early feed restriction or use of slow growing broilers should be implemented to avoid rapid growth rate, which is associated with locomotor problems. This review aims to summarise and address current knowledge on skeletal disorders associated with Staphylococcus spp. infection in poultry.

Keywords: Poultry; Staphylococcus; bacterial chondronecrosis; chicken; femoral head necrosis; infectious disease; lameness; skeletal disorders; welfare.

Figure 1.

Stages of BCO lesions in proximal femoral head of broiler chicken. Normal head of femur, asterisk (★) shows the fovea for ligament of femoral head (fovea capitis femoris); FHS – femoral head separation (epiphyseolysis); FHT – femoral head transitional degeneration; FHN – femoral head necrosis; Arrow head (▶) indicates bacterial fibriscess. Arrows (→) indicate lesions. (Figure source: Authors).

Figure 2.

Examples of skeletal disorders associated with Staphylococcus infections in poultry A) Swollen hock joint and tarsometatarsus indicating unilateral arthritis, tenosynovitis in a 19-week-old Hy-Line Brown rooster. B) Arthritis of the left hock joint in a 5-week-old broiler chicken – swelling and yellowish fibrinous exudate (arrow). C, D) Bumblefoot in a 11-week-old turkey: swollen feet, toes (arrows) and characteristic black scab on footpad (beside a normal foot in another turkey). E, F, G) Dyschondroplasia with bacterial osteomyelitis (arrows) of tarsometatarsus in a broiler chicken. F) Sagittal section through the distal tarsometatarsus shows mass of cartilage and osteomyelitis. G) Necrosis of cartilage and multiple (intralesional) bacterial colonies (arrows). Haematoxylin-eosin. 100×. (Figure source of A–E: Authors; Source of F–G: Izabella Dolka, Department of Pathology and Veterinary Diagnostics, Institute of Veterinary Medicine, Warsaw University of Life Sciences – SGGW, Poland).