Eight new beta-lactam antibiotics and rosaramicin were tested for their activity against penicillin-susceptible and multiply resistant pneumococci. All of the beta-lactam drugs were 50- to 150-fold less active against the drug-resistant pneumococci when compared with their activity against penicillin-susceptible pneumococci. Rosaramicin activity was similar to that of erythromycin.

In vitro testing of 229 group B streptococcal isolates from a variety of patients with invasive infections indicated uniform penicillin G susceptibility. However, 17 (7.4%) isolates were resistant to erythromycin and 8 (3.4%) were resistant to clindamycin. These results support the continued use of penicillin G as the drug of choice for the treatment and prevention of group B streptococcal dise...

In Western Australia, Neisseria meningitidis serogroup W clonal complex 11 became the predominant cause of invasive meningococcal disease in 2016. We used core-genome analysis to show emergence of a penicillin-resistant clade that had the penA_253 allele. This new penicillin-resistant clade might affect treatment regimens for this disease.

A survey of 303 urban and 156 rural children showed nasopharyngeal carriage of relatively resistant Streptococcus pneumoniae organisms in 14.2% and 19.2% of children, respectively. These organisms have minimum inhibitory concentrations for penicillin in the range of 0.12-1 microgram/ml. An analysis of 40 relatively resistant S. pneumoniae strains showed resistance to co-trimoxazole in 47.5%, tr...

Objective-To study the epidemiology of Neisseria gonorrhoeae that exhibit both chromosomal and plasmid-mediated resistance to penicillin. Materials and methods-A total of 1589 strains of N gonorrhoeae isolated from patients attending St Mary's Hospital, London were tested for both their susceptibility to penicillin and for their auxotype and serotype. Results-Of the 940 non-penicillinase produc...

Some transformable bacteria have acquired target-mediated antibiotic resistance by horizontal genetic exchange of fragments of chromosomal genes. The resistant strains express variants of the antibiotic target that are metabolically active but exhibit a lowered affinity for the antibiotic. The alleles encoding these resistant proteins are mosaics comprising DNA derived from the host and other b...