Staphylococcus spp

Classification

Taxonomy

• Kingdom: bacteria.
• Subkingdom: posibacteria.
• Phylum: firmicutes.
• Class: bacilli.
• Order: bacillales.
• Family: staphylococcaceae.
• Genus: staphylococcus.

Etymology

• Gk: staphule- bunch of grapes; Gk: kokkos- grain, berry, seed.

Distribution

• Staphyloccal spp occurs worldwide as commensals on skin, mucus membranes, upper respiratory tract, lower urogenital tract and transiently in the digestive tract skin of animals (and humans).
• In cattle, S.aureus has been historically reported as the most clinically relevant pathogenic species due to it causing mastitis and udder impetigo.
• In recent years, coagulase-negative staphylococci (CNS) have become the most common bovine mastitis isolate in many countries and are now considered as an emerging mastitis pathogen. CNS prevalence is higher in primiparous cows than in older cows. CNS appear to be less pathogenic and infection mostly remains sub clinical. Currently CNS mastitis is not a therapeutic problem as cure rates after antimicrobial treatment are usually high.

Significance

• Staphylococcal strains display species-specific affinity. However, when animals transfer some strains (eg methicillin resistant S.aureus) this is of clinical importance.
• Cause pyogenic infections.
• Staphylococcal mastitis is a significant problem worldwide.
• Species which have been isolated from cattle include:
  • Coagulase-positive staphylococci (CPS):
    • S. aureus (found in the nares, udder and most common cause of mastitis. Can also cause wound infections).
    • S. hyicus (found on the skin. Can populate mange lesions and can cause chronic low-grade intra mammary infections)
    • S. intermedius (does not appear to be an important mastitis pathogen).
  • Coagulase-negative staphylococci (CNS):
    • S. capitis (found in milk, isolated from clinical mastitis cases).
    • S. chromogenes (found in milk, high prevalence in mastitis cases).
    • S. cohnii (found in milk, occasionally causes mastitis).
    • S. hemolyticus (found on teat skin and in milk, occasionally isolated from mastitis cases).
    • S. hominis (found in milk).
    • S. saprophyticus (found in nostrils).
    • S. vitulinus (found on skin).
    • S. xylosus (found on teat skin and in milk, occasionally isolated from mastitis cases).
    • S. pasteuri (found on teat skin).
    • S. fleurettii (found on teat skin).
    • S. succinus (found on teat skin).
    • S. epidermidis (found in milk and skin infections) .
    • S. simulans (found in milk, high prevalence in mastitis cases).
    • S. arlettae (found in teat canal).
    • S. auricularis (found on skin).
    • S. warneri (found in milk, occasionally isolated from mastitis cases and there is evidence to suggest association of this organisms with spontaneous abortion in cattle. 
    • S. devriesei (found on teat apices).

• Currently CNS mastitis is not a therapeutic problem as cure rates after antimicrobial treatment are usually high.
• Methicillin resistant staphylococcus aureus (MRSA) is a growing problem amongst bovine patients.