Various auxotrophs are recovered from a penicillin enrichment cycle with differing efficiencies. Reconstruction experiments indicate that, under starvation conditions in the presence of penicillin, most auxotrophs undergo some death, whereas prolineless mutants are virtually immune to penicillin-induced killing.

The morphological effects of penicillin on gram-negative nonsporeforming rods, especially E8cherichia coli, have been studied by several authors. Gardner (1940) reported that grotesque forms of E. coli resulted from autolytic swelling when this organism was treated with penicillin and that elongated, swollen cells resulted from incomplete fission. Weiss (1943) showed by electron micrographs tha...

Steadily increasing interest in penicillin as a chemotherapeutic agent has led to a parallel increase in the demand for penicillin for clinical application and chemical studies. Penicillin is produced in minute quantities by Penicillium notatum so that filtrates from the mold represent exceedingly dilute solutions of penicillin from which the active agent is extracted. The magnitude of the prob...

Penicillin allergy remains the most common drug allergy, with a reported prevalence of 10% in the United States. Epidemiology of penicillin allergy in outpatient populations is relatively scarce. This study sought to determine the prevalence and characteristics of reported penicillin allergy in an urban outpatient population and to identify trends in clinical evaluation and management from a te...

In this paper we demonstrate the advantages of a new molecular typing procedure, multilocus sequence typing, for the unambiguous characterization of penicillin-resistant pneumococci. The sequences of approximately 450-bp fragments of seven housekeeping genes were determined for 74 penicillin-resistant Taiwanese isolates of Streptococcus pneumoniae (MIC of penicillin > 0.5 microgram/ml). The com...

Compared with most penicillin-susceptible isolates of Streptococcus pneumoniae, penicillin-resistant clinical isolate Hun 663 contains mosaic penicillin-binding protein (PBP) genes encoding PBPs with reduced penicillin affinities, anomalous molecular sizes, and also cell walls of unusual chemical composition. Chromosomal DNA prepared from Hun 663 was used to transform susceptible recipient cell...

The combination of beta-lactam antibiotics and macrolides is often recommended for the initial empirical treatment of acute pneumonia in order to obtain activity against the most important pathogens. Theoretically, this combination may be inexpedient, as the bacteriostatic agent may antagonize the effect of the bactericidal agent. In this study, the possible interaction between penicillin and e...

Laboratories that reported isolations of Streptococcus sanguis from blood cultures to the Communicable Disease Surveillance Centre (CDSC) Colindale were requested to submit strains to Bath Public Health Laboratory to allow the prevalence of penicillin tolerance within different biotypes of this species to be studied. One hundred and fifty one Streptococcus spp were received from 78 United Kingd...

Amikacin has been shown to antagonize the bactericidal effect of penicillin against strains of Streptococcus faecalis which produce aminoglycoside 3'-phosphotransferase. The mechanism by which this phenomenon occurs was studied with an enzyme-producing strain (8436) and an enzyme-negative strain (8436c) derived by curing the former with novobiocin. Combinations of amikacin with beta-lactam anti...

in the present study, the effect of intrauterine infusion of zataria multiflora extract on the clinical endometritis was investigated. vaginal examination, transrectal palpation and ultrasonography were used to inspect the genital tract at 30-40 days in milk and two weeks later the same approach was applied. cows with clinical endometritis were randomly divided into three treatment groups: z. m...