The article by Caputo and coworkers1 provides an excellent comprehensive review of the status of penicillin resistance in the pneumococcus. In this context, I would like to highlight some additional recent data relating to this subject.
Using multilocus enzyme electrophoresis, a close genetic association was found between clones of penicillin-resistant pneumococci isolated from Houston, Tex, and penicillin-resistant clones recovered in Alaska, Iceland, and Spain.2 It is suggested that the common resistant clones have a recent ancestor or, alternatively, that isolates of a particular pneumococcal phylogenetic lineage are predisposed to develop penicillin resistance. Transformation studies were carried out using DNA from penicillin-resistant isolates of Streptococcus mitior and Streptococcus sanguis and a recipient penicillin-susceptible strain of pneumococcus (minimum inhibitory concentration, 0.006 mg/L).3 The resulting generation of penicillin resistance in the pneumococcal isolates (minimum inhibitory concentrations, 0.03 to 2 mg/L) suggest that pneumococcal isolates may develop penicillin resistance by transfer
Anand A. Penicillin-Resistant Pneumococci. Arch Intern Med. 1994;154(1):109-111. doi:10.1001/archinte.1994.00420010145021