– The present study deals with the ability of 11 bacterial strains, in various combinations, to induce periapical reactions. The indigenous oral bacteria were originally isolated from an experimental apical periodontitis in monkey. Eight of the strains were a complete collection isolated from one root canal. These strains were inoculated together, in equal proportions, into 12 root canals. In addition, 63 canals were inoculated with other combinations or separate strains. At the end of the experimental period it was found that in the mixed infections the Bacteroides oralis strain predominated in most root canals. In contrast, this Bacteroides strain was not reisolated in any of nine root canals when inoculated in a pure culmfe. Enterococci, however, survived as pure cultures in all canals. The mixed infections showed the greatest capacity ofindticing apical periodontitis, as revealed by radiography, and most pronounced was the “eight‐strain collection”. The facultatively anaerobic streptococci induced only weak periapical reactions.

Serotypes of serious, sometimes fatal, streptococcal infections in Sweden during 1988-1989 were analyzed. The T1M1 type totally dominated, representing almost 70% of all group A streptococci from serious and uncomplicated infections at the peak of the outbreak. Immunoblots of isolates from various patient groups showed that all isolates produced high amounts of erythrogenic toxin (ET) B and high amounts of ET-C, whereas ET-A was released only in small amounts and from few isolates. ELISAs showed high antibody levels to these toxins and to the M1 antigen in patients with uncomplicated infections. Low antibody levels against M1 were seen in patients with bacteremia and in fatal cases; the latter also had low antibody levels against ET-B. It seems likely that a combination of production of large amounts of toxin and low antibody titers to it and to the M antigen of the infecting isolate are determining factors for the outcome of the infection. No signs of primary immune deficiency were noted.

In Finland since 1988 there has been a rapid and substantial increase in resistance to erythromycin in group A streptococci. The extent of this resistance is particularly serious since there are only a few alternative antibiotics available for peroral treatment of group A streptococcal infections.

No abstract

This prospective, multicentre, randomized, double-blind and placebo controlled study was performed to describe the natural course of uncomplicated lower urinary tract infection (UTI). A total of 1143 women 18 y and above, consulting at 18 primary health care centres in northern Sweden for symptoms suggestive of UTI were included. The symptoms urgency, dysuria, suprapubic pain and loin pain were registered, and urine cultures performed at inclusion and follow-up visits 8-10 d and 5-7 weeks later. Associations between all symptoms and bacteriuria or bacterial counts were unpredictable. Eradication of symptoms and bacteriuria and combinations of them were studied in 288 patients placebo treated for 7 d, of whom 39% dropped out after the first follow-up visit. The spontaneous cure rate of symptoms was 28% after the first week, and 37% had neither symptoms nor bacteriuria after 5-7 weeks. Considering the high dropout rate after the first follow-up visit, the spontaneous cure rate of symptoms and bacteriuria was calculated to 24% at the end of study. We conclude that patient near-laboratory tests are required to establish the diagnosis of lower UTI, and the guidelines for diagnosis of UTI need to be revised.