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PURPOSE: Group B streptococcus (GBS) colonizes the gastrointestinal and vaginal mucosa in healthy adults, but has also become an increasing cause of invasive infection. The aims of this study were to describe the incidence and factors associated with the occurrence of invasive GBS disease in adults in Norway. METHODS: We performed a nationwide retrospective case-control study of invasive GBS infections during 1996-2019, with two control groups; invasive Group A streptococcal disease (GAS) to control for changes in surveillance and diagnostics, and a second representing the general population. RESULTS: A total of 3710 GBS episodes were identified. The age-standardized incidence rate increased steadily from 1.10 (95% CI 0.80-1.50) in 1996 to 6.70 (95% CI 5.90-7.50) per 100,000 person-years in 2019. The incidence rate had an average annual increase of 6.44% (95% CI 5.12-7.78). Incidence rates of GAS varied considerably, and there was no evidence of a consistent change over the study period. GBS incidence was highest among adults > 60 years of age. Cardiovascular disease, cancer, and diabetes were the most common comorbid conditions. There was a shift in the distribution of capsular serotypes from three dominant types to more equal distribution among the six most common serotypes. CONCLUSIONS: The incidence of invasive GBS disease in adults increased significantly from 1996 to 2019. The increasing age of the population with accompanying underlying comorbid conditions might contribute to the increasing burden of invasive GBS disease. Interestingly, type 1 diabetes was also associated with the occurrence of invasive GBS disease.
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BACKGROUND: Bacteremia frequently complicates cytostatic treatment of hematological malignancies. Initial antibiotic treatment is chosen empirically before the results of cultures are available. Rational choices depend on updated knowledge of microbial resistance patterns. We have examined microorganisms in blood cultures over a 10-year period and compared them with the preceding 5-year period. MATERIAL AND METHODS: We analyzed isolates from blood cultures in patients with a hematological malignant disorder treated in the Hematology Unit, St. Olavs Hospital during the years 1995 - 2005. RESULTS: We found 373 isolates and 322 episodes of bacteremia in 225 patients. Most patients had acute leukemia or myeloma, with neutropenia after cytostatic treatment. The dominating pathogens were Escherichia coli (20 %), coagulase-negative staphylococci (13 %) and alpha-haemolytic streptococci (10 %). Enterococcus infections seem to occur more frequently and were associated with a high mortality. Gram-negative organisms constituted 48 % and gram-positive organisms 48 % of the isolates. About 3 / 4 of the patients had infections with penicillin-resistant bacteria. There was a low prevalence of organisms resistant to aminoglycoside. Acute leukemia patients with bacteremia had a 30-days all-cause mortality of 10.3 %. INTERPRETATION: We found small changes in the pattern of pathogens and antibiotic resistance over time. The rates of antibiotic resistance were favorable compared to other European countries. The mortality rate seems to be unchanged and acceptable. Penicillin G and aminoglycoside can still be considered as first-line treatment for suspected bacteremia in neutropenic patients in Norway.