[Experience using a new system for identifying coliform bacteria].

Chemostats supplied with limited lactose were used to ask whether it was possible to generate and isolate any mutant of Escherichia coli lactose permease which allowed cells to grow faster. The permease and beta-galactosidase activities of the chemostat culture initially rose together to reach a plateau. After 30 days, the former underwent a second increase alone. From this culture, a faster-growing mutant was isolated. Its permease gene was cloned, sequenced, and found to have a single base pair changed. Thymine at position 199 was changed to guanine, resulting in serine 67 being substituted by alanine. Cells bearing this mutant in the plasmid could grow faster than parents in 10 microM lactose. The Km of the mutant permease toward lactose was 1.4 mM, about half of the wild-type value. Thus, a mutant with higher affinity for substrate could be selected from the chemostat.

Bacteriological Techniques↗

PubMed1996

[Indications for laboratory testing of gonorrhea. New recommendations from the Working Group against Gonorrhea].

Culture testing for sexually transmitted Neisseria gonorrhoeae infection is widely used in Norwegian general practice. The gain from this testing is very low, since gonorrhoea is almost eradicated in Norway. This reduces the cost-effectiveness of the testing. In cooperation with a panel of medical microbiologists, gynaecologists, venerologists, general practitioners and public health specialists, we have reviewed the literature and drawn up a set of recommendations for the use of culture testing for gonococcal infection to suit the epidemiological situation in Norway. We emphasise clinical testing of men and women, partner notification and tests-of-cure. We do not recommend opportunistic screening for gonococci in any situation whatsoever.

Bacteriological Techniques↗