This well-known phenomenon was the origin of the major penicillin-resistant clone (serotype 14 variant of the Spain 9V-ST156 clone), which caused invasive pneumococcal disease in Spain in the 2000s (4,6).
A key example is the promotion of penicillin-resistant Streptococcus pneumoniae, a worldwide health problem that was originally described in South Africa (SA), where it is has been strongly associated with injudicious use of antibiotics in patients with viral infections.
IDSA guidelines emphasize importance of addressing bacterial resistance in selection of first-line therapy where the endemic rate of penicillin-resistant Streptococcus pneumoniae is greater than 10%: Antimicrobial resistance by bacterial organisms is an increasing area of concern, and inappropriate antimicrobial use is believed to be an important driver.
Today, penicillin-resistant TB is known to be connected with the onset of Crohn's disease, but that is now being blamed on the badgers rather than obviously unhygienic conditions of most milking parlours only sustained by an over-use of antibiotics.
As a result, it has a broad spectrum of activity including activity against methacillin-resistant Staphalococcus aureus (MRSA), vancomycin-resistant Enterococcus species (VRE), and penicillin-resistant Streptococcus pneumoniae, among others.