Emergence of a high-level cefotaxime-resistant Streptococcus pneumoniae strain in New Zealand

An increase in the number of cefotaxime-resistant pneumococci referred for surveillance to a central laboratory in New Zealand occurred in 1997-1998. The MIC of cefotaxime for 113 of 216 cefotaxime-resistant isolates of Strep tococcus pneumoniae referred was greater than or equal to4 mg/L, Most of th e 113 isolates exhibited the same antibiotic resistance pattern and belonge d to serotype 19F, To investigate the genetic relatedness of the isolates, 48 serotype 19F pneumococci with varying susceptibility to cefotaxime were further typed by macro-restriction analysis by use of pulsed-held gel elect rophoresis, These results suggested that a multiresistant 19F strain of S. pneumoniae,vith high-level cefotaxime resistance had emerged from a pre-exi sting serotype 19F strain.