| Abstract: |
The genus Staphylococcus is a member of a diverse group of the family Micrococcaceae that are capable of causing a wide array of diseases. They are characterized as typical catalase-positive, Gram-positive cocci that produce an array of extracellular and cell surface virulence factors. The genomes of multiple strains of S. aureus have been sequenced and these data provide invaluable clues to gene regulation in the infection process. Staphylococci are normal commensals colonizing about one-third of the population. The colonizers are usually harmless unless they gain access via a cut or abrasion. Most people have antibodies to staphylococcal products but these are generally not protective against infection and multiple bouts of infection can occur. However, antibodies against exotoxins appear to protect against staphylococcal sepsis as well as against toxin-mediated entities such as staphylococcal toxic shock. Although staphylococci were originally sensitive to penicillin, virtually all current clinical isolates are now resistant. Further, multiple drug resistances are common and exemplified by the healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) strains. These strains are typically resistant to the antibiotics commonly used to treat infections and recently many have acquired resistance to vancomycin, the antibiotic of last resort. In addition, community-acquired MRSA (CA-MRSA) strains have been appearing in community-acquired infections; these strains are typically susceptible to antibiotics such as gentamicin, clindamycin, and trimethoprim-sulfamethoxazole in contrast to HA-MRSA strains. There has been a vigorous effort to identify and characterize new antibiotics and to develop effective vaccines for treatment and prevention of infections due to both HA-MRSA and CA-MRSA. © 2015 Elsevier Inc. All rights reserved. |
