As we have seen, one way to classify bacteria is by their shape (§18.104.22.168). Spherical bacteria are called cocci, sing. coccus, from Greek κόκκος (kókkos) ‘grain, seed’. The word coccus (pl. cocci) by itself is used now for any spherical bacterium. Rod-shaped bacteria, on the other hand, are called băcilli, sing. băcillus ‘small staff, wand’, diminutive of Latin băcŭlum ‘stick, staff’.
S. aureus can cause a range of illnesses, from minor skin infections, such as pimples, impetigo, boils, cellulitis, folliculitis, carbuncles, scalded skin syndrome, and abscesses, to life-threatening diseases such as pneumonia, meningitis, osteomyelitis, endocarditis, toxic shock syndrome, bacteremia, and sepsis. It is still one of the five most common causes of hospital-acquired infections and is often the cause of wound infections following surgery. Each year, around 500,000 patients in hospitals of the United States contract a staphylococcal infection, chiefly by S. aureus. Up to 50,000 deaths each year in the USA are linked with S. aureus infections.[i]