[Tobacco smoking and risk of hip fracture in men and women. Results from the Hovedstadens Center for Prospective Population Studies]. / Tobaksrygning og risiko for hoftebrud hos maend og kvinder. Resultater fra Hovedstadens Center for Prospektive Befolkningsstudier.

INTRODUCTION: In the present population-based cohort study, we prospectively determined the influence of current, previous, and cumulative smoking history on the risk of hip fracture in men and women and addressed the issue of possible gender difference in susceptibility to tobacco smoking. MATERIAL: A total of 13,393 women and 17,379 men, initially examined between 1964 and 1992, were followed up until 1997 for their first admission because of hip fracture. RESULTS: During follow-up, a total of 1169 hip fractures were identified. After adjustment for potential confounders, female current smokers had a relative risk of hip fracture of 1.36 (1.12-1.65) and male smoked 1.59 (1.04-2.43) relative to those who have never smoked. In both sexes, the relative risk of hip fracture gradually increased with current and accumulated tobacco consumption. A test for interaction between gender and smoking habits was insignificant. Men who stopped smoking for more than five years had a lower risk of hip fracture than men who currently smoked, whereas no such risk reduction was seen in female ex-smokers. CONCLUSION: Tobacco smoking is an independent risk factor for hip fracture in men and women, and there appears to be no gender differences in the smoking-related risk. Men who stopped smoking for more than five years had lower risk of hip fracture than men who currently smoked, whereas no such risk reduction was seen in female ex-smokers.

[Beer, wine, spirits and mortality]. / Øl, vin, spiritus og dØdelighed.

A population based cohort study investigates the association between alcohol intake and mortality from all causes, coronary heart disease and cancer. The design is prospective with baseline assessment of intake of beer, wine and spirits, smoking habits, educational level, physical activity, and body mass index and a total of 257,859 person-years follow-up on mortality. A total of 4,833 participants died, of these 1,075 from coronary heart disease and 1,552 of cancer. Compared with non-drinkers, light drinkers who avoided wine, had a relative risk of death from all causes of 0.90 (0.82-0.99) and those who drank wine had a relative risk of 0.66 (0.55-0.77). Heavy drinkers who avoided wine were at higher risk of death from all causes than were heavy drinkers who included wine in their alcohol intake. Wine drinkers had significantly lower mortality from both coronary heart disease and cancer than did non-wine drinkers (p = 0.007 and p = 0.004, respectively). In conclusion, wine intake may have a beneficial effect on all cause mortality that is additive to that of alcohol. This effect may be attributable to a reduction in death from both coronary heart disease and cancer.

[Beer, wine, spirits and mortality. Results from a prospective population study]. / Øl, vin, spiritus og dødelighed. Resultater fra Hovedstadens Center for Prospektive Befolkningsstudier.

INTRODUCTION: The aim of the present population-based cohort study was to examine the association between alcohol intake and mortality from all causes, coronary heart disease, and cancer. METHODS: A prospective population study with baseline assessment of beer, wine and spirit consumption, smoking habits, educational level, physical activity, and body mass index in a total of 257,859 person-years follow-up on mortality. RESULTS: A total of 4833 participants died, 1075 of these from coronary heart disease and 1552 of cancer. Compared with non-drinkers, light drinkers, who avoided wine, had a relative risk of death from all causes of 0.90 (0.82-0.99) and those who drank wine had a relative risk of 0.66 (0.55-0.77). Heavy drinkers, who avoided wine, were at higher risk of death from all causes than were heavy drinkers, who included wine in their alcohol consumption. Wine drinkers had a significantly lower mortality from both coronary heart disease and cancer than had non-wine drinkers (p = 0.007 and p = 0.004, respectively). CONCLUSION: A moderate consumption of wine may have a beneficial effect on all causes of mortality, which is additive to that of alcohol. This effect may be attributable to a reduction in death from both coronary heart disease and cancer.

Type of alcohol consumed and mortality from all causes, coronary heart disease, and cancer.

BACKGROUND: Although the J-shaped relation between alcohol intake and mortality has been reproduced in many large cohort studies, the question of whether the effects of beer, wine, and spirits differ remains controversial. OBJECTIVE: To examine the relation between intake of different types of alcohol and death from all causes, coronary heart disease, and cancer. DESIGN: Pooled cohort studies in which intake of beer, wine, and spirits; smoking status; educational level; physical activity; and body mass index were assessed at baseline. SETTING: Copenhagen, Denmark. PARTICIPANTS: 13 064 men and 11 459 women 20 to 98 years of age. MEASUREMENTS: Number of deaths and time to death from all causes, coronary heart disease, and cancer during follow-up. RESULTS: During 257 859 person-years of follow-up, 4833 participants died. J-shaped relations were found between total alcohol intake and mortality at various levels of wine intake. Compared with nondrinkers, light drinkers who avoided wine had a relative risk for death from all causes of 0.90 (95% CI, 0.82 to 0.99) and those who drank wine had a relative risk of 0.66 (CI, 0. 55 to 0.77). Heavy drinkers who avoided wine were at higher risk for death from all causes than were heavy drinkers who included wine in their alcohol intake. Wine drinkers had significantly lower mortality from both coronary heart disease and cancer than did non-wine drinkers (P = 0.007 and P = 0.004, respectively). CONCLUSION: Wine intake may have a beneficial effect on all-cause mortality that is additive to that of alcohol. This effect may be attributable to a reduction in death from both coronary heart disease and cancer.

Tobacco smoking and risk of hip fracture in men and women.

BACKGROUND: Previous findings suggest that tobacco smoking increases the risk of hip fracture in women. A similar adverse effect of smoking is suspected to be present in men, but bone mineral density studies have raised the concern that men may be more sensitive to the deleterious effect of smoking on bone than women. In this study we prospectively determined the influence of current, previous, and cumulative smoking history on risk of hip fracture in men and women and addressed the issue of possible gender difference in the susceptibility to tobacco smoking. METHODS: Pooled data from three population studies conducted in Copenhagen with detailed information on smoking habit. A total of 13,393 women and 17,379 men, initially examined between 1964 and 1992, were followed until 1997 for first admission due to hip fracture. The relative risks (RR) of hip fracture associated with smoking were estimated by means of multiplicative Poisson regression models. RESULTS: During follow-up, 722 hip fractures were identified in women, and 447 in men. After adjustment for potential confounders, including body mass index, female current smokers had an RR of hip fracture of 1.36 (95% CI: 1.12-1.65) and male smokers 1.59 (95% CI: 1.04-2.43) relative to never smokers. In both sexes, the RR of hip fracture gradually increased by current and accumulated tobacco consumption. The RR were consistently higher in men than in women, but the test for interaction between sex and tobacco smoking was insignificant. After 5 years, male ex-smokers had an adjusted RR of 0.73 (95% CI: 0.55-0.98) relative to current smokers, while no significant decrease in risk was observed in female ex-smokers (RR = 0.91; 95% CI: 0.72-1.17)). Approximately 19% of all hip fractures in the present study population were attributable to tobacco smoking. CONCLUSION: Tobacco smoking is an independent risk factor for hip fracture in men and women, and there appears to be no gender differences in smoking related risk. Smoking cessation reduces the risk of hip fracture in men after 5 years, while the deleterious effect of smoking seems to be more long-lasting in female ex-smokers.

A randomized trial assessing the impact of written information on outpatients' knowledge about and attitude toward randomized clinical trials. The INFO trial group.

To improve the patient education process in clinical research, three information materials describing general aspects of design and conduct of randomized clinical trials were developed. The materials varied in length, reading ability level, and reader appeal. Their influence on knowledge about and attitude toward randomized clinical trials was assessed in a randomized, parallel group, evaluator-blinded trial among 415 outpatients. The patients were randomized to the following groups: control (no intervention), leaflet, brochure, or booklet. Knowledge was assessed by a 17-item multiple-choice questionnaire and attitude was assessed by a 32-item Likert questionnaire at entry and 2 weeks after the intervention. The interventions and the questionnaires were pilot tested and power calculations were performed. At entry, the mean knowledge score was 7.9 points. At follow-up, the knowledge scores increased by 0.5 for the control, 1.0 for the leaflet, 1.6 for the brochure, and 1.4 for the booklet. The brochure and the booklet improved the knowledge score significantly compared with the control. The general attitude was positive at entry (mean 71.5 points). Only the booklet significantly increased the total attitude score (4.8 points) and the randomized clinical trials attitude subscale score (1.8 points). In conclusion, written information significantly improved outpatients' knowledge about and attitude toward randomized clinical trials. Detailed rather than brief information was more effective. Control Clin Trials 2000;21:223-240

Hormone replacement therapy and hip fracture risk: effect modification by tobacco smoking, alcohol intake, physical activity, and body mass index.

The authors prospectively studied the overall effect of hormone replacement therapy (HRT) on hip fracture risk and the effect modification by behavioral habits and body mass index. A total of 6,159 postmenopausal women from the Copenhagen Center for Prospective Population Studies, Copenhagen, Denmark, with initial examination in 1976-1978 were followed until 1993. During follow-up 363 hip fractures were identified. Women who reported current use of HRT had a lower risk of hip fracture as compared with women who were nonusers (relative risk (RR) = 0.71; 95 percent confidence interval (CI): 0.50, 1.01). Use of HRT was associated with a lower risk of hip fracture in former (RR = 0.55; 95 percent CI: 0.22, 1.37) and current (RR = 0.61; 95 percent CI: 0.38, 0.99) smokers but not in never smokers (RR = 1.10; 95 percent CI: 0.60, 2.03). HRT was also associated with lower risk of hip fracture among alcohol drinkers (RR = 0.36; 95 percent CI: 0.14, 0.90) and among sedentary women (RR = 0.42; 95 percent CI: 0.18, 0.98) but not among nondrinkers (RR = 0.99; 95 percent CI: 0.61, 1.61) and physically active women (RR = 0.92; 95 percent CI: 0.42, 2.04). There was no evidence of interaction between use of HRT and body mass index. In conclusion, the protective effect of HRT on hip fracture appears to be strongest in women who ever smoked, in women who drink alcohol, and in women who are sedentary. The results suggest that history of behavioral habits offers important information concerning the probable degree of protection against hip fracture afforded by HRT.

Alcohol intake, beverage preference, and risk of hip fracture in men and women. Copenhagen Centre for Prospective Population Studies.

The authors prospectively studied the association between quantity and type of alcohol intake and risk of hip fracture among 17,868 men and 13,917 women. Analyses were based on pooled data from three population studies conducted in 1964-1992 in Copenhagen, Denmark. During follow-up, 500 first hip fractures were identified in women and 307 in men. A low to moderate weekly alcohol intake (1-27 drinks for men and 1-13 drinks for women) was not associated with hip fracture. Among men, the relative risk of hip fracture gradually increased for those who drank 28 drinks or more per week (relative risk (RR) = 1.75, 95% confidence interval (CI) 1.06-2.89 for 28-41 drinks; RR = 5.28, 95% CI 2.60-10.70 for 70 or more drinks) as compared with abstainers. Women who drank 14-27 drinks per week had an age-adjusted relative risk of hip fracture of 1.44 (95% CI 1.03-2.03), but the association weakened after adjustment for confounders (RR = 1.32, 95% CI 0.92-1.87). The risk of hip fracture differed according to the type of alcohol preferred: preferrers of beer had a higher risk of hip fracture (RR = 1.46, 95% CI 1.11-1.91) than preferrers of other types of alcoholic beverages. The corresponding relative risks for preferrers of wine and spirits were 0.77 (95% CI 0.58-1.03) and 0.82 (95% CI 0.58-1.14), respectively. In conclusion, an alcohol intake within the current European drinking limits does not influence the risk of hip fracture, whereas an alcohol intake of more than 27 drinks per week is a major risk factor for men.

Trends in smoking prevalence in Danish adults, 1964-1994. The influence of gender, age, and education.

BACKGROUND: Studies of time trends in smoking prevalence provide a better understanding of the determinants of smoking. The present study analyses changes over time in the prevalence of smoking and heavy smoking in relation to sex, age, and education. METHODS: Data on smoking behaviour were collected by questionnaire in random samples of the general population in the area of Copenhagen. The database used included 71,842 measurements of smoking behaviour for 32,156 subjects aged 30 years or more, who had been examined at intervals between 1964 and 1994. In bi- and multivariate analyses the effects of sex, age, education, time period, and study group on the prevalence of smoking and of heavy smoking were assessed. RESULTS: Smoking was least prevalent in women, in the oldest age group (more than 70 years), and among those with 8 years or more of school education. During the study period (from 1964/74 to 1990/94), the prevalence of smoking decreased from 72% to 54% in men and from 52% to 46% in women. In both men and women this decrease was smallest in the least educated (less than 8 years of school education). Heavy smoking was also least prevalent in women, in the oldest age group, and among the well educated. During the study period, the unadjusted prevalence of heavy smoking decreased from 52% to 38% in men, while it increased from 17% to 21% in women. The multivariate analysis showed that the time trend for heavy smoking only depended on sex, while educational attainment and age had no impact on the trend. CONCLUSION: During the last 30 years the prevalence of smoking has decreased in Denmark. The decrease has been smallest in women, and among the least educated, and the increasing trend in the prevalence of heavy smoking in women is a cause for concern.

Knowledge of HIV-positivity had no impact on AIDS survival time among Danish AIDS patients 1980-95.

OBJECTIVE: To examine the impact of the time period from first positive HIV test to AIDS diagnosis and other variables on survival after AIDS diagnosis. MATERIALS AND METHODS: All adult AIDS patients diagnosed and reported to the national surveillance unit in Denmark in the period 1980 through June 1995. RESULTS: A total of 1745 patients was diagnosed in the period, and for 1631 (93.5%) the date of first positive HIV test was known. The median interval between this test and AIDS diagnosis was 912 d. Overall, 473 patients (29.0%) were found to be HIV-positive close to the AIDS diagnosis (< or = 4 months). The time interval between first positive HIV test and AIDS diagnosis varied by transmission categories. Patients older than 40 y had a higher mortality than younger patients. Patients infected by blood products had the highest mortality. The survival time was shortest for patients presenting with HIV-wasting or HIV-encephalopathy or with > or = 1 AIDS-defining disease. The time interval between first positive HIV test and AIDS diagnosis had no impact on survival. CONCLUSION: No association was found between survival time and the time interval between first positive HIV test and AIDS diagnosis. Older age and transmission by blood or blood products were associated with shorter survival from AIDS diagnosis.

Outpatients' knowledge about and attitude towards clinical research and randomized clinical trials. The INFO Trial Group.

OBJECTIVES: To investigate the knowledge about randomized clinical trials and the attitude towards clinical research among Danish outpatients and to examine the relationships between outpatient demographic variables and knowledge and attitude. SETTING: Outpatients (n = 415) were recruited from four departments at a university hospital in Copenhagen. METHODS: The participants answered an 18 item multiple choice test evaluating knowledge about randomized clinical trials and a 32 item Likert format questionnaire evaluating attitudes towards clinical research in general and randomized clinical trials. Assessment of scales for knowledge and attitudes was performed using Rasch analysis and Cronbach's alpha. Associations between demographic variables, knowledge score and attitude score were examined using analysis of variance. RESULTS: Mean age for all outpatients was 46 years (range 18-88 years); 251 (60%) were females. A total of 27 outpatients (7%) had previously participated in a randomized clinical trial. Mean knowledge score (number of correct answers out of a maximum of 17) was 7.9 (SD 3.1). Patients in the younger age groups and patients with longer education had significantly higher knowledge scores (p < 0.001). The effect of age group (estimated increase in knowledge score relative to the group 60-89 years) was: 18-29 years 1.2 (SE 0.4); 30-39 years 2.0 (SE 0.4); and 40-59 years 1.6 (SE 0.4). The effect of education (estimated decrease in knowledge score relative to patients with > 12 years of education) was: < 7 years 3.4 (SE 0.4); and 8-11 years 2.0 (SE 0.3). Mean total attitude score was 74.8 (SD 14.8) on a scale from 0-128. Compared to female patients, male patients had an estimated 5.1 points (SE 1.5) higher attitude score (p < 0.001). There was a weak but significant positive association (r = 0.38; p < 0.001) between the knowledge score and the total attitude score. CONCLUSION: Among Danish outpatients knowledge about randomized clinical trials is better in the younger age groups and in individuals with longer education. Overall, better knowledge was associated with a more positive attitude towards clinical research. The question is whether it is possible by simple means to increase knowledge about clinical research and whether an increase in knowledge may positively affect the attitude towards clinical research in individual patients.

Epidemiology of Klebsiella bacteraemia: a case control study using Escherichia coli bacteraemia as control.

Epidemiological data from 117 episodes of Klebsiella bacteraemia were compared with those from matched controls with Escherichia coli bacteraemia. Cases and controls were obtained from 20,631 blood cultures taken from patients in Hvidovre Hospital between 1990 and 1992. The data studied included: sex and age, risk factors, portal of entry, outcome, nosocomial acquisition and distribution within the hospital. The incidence of Klebsiella bacteraemia was 9.3/10,000 admissions (76% Klebsiella pneumoniae; 24% Klebsiella oxytoca). Patients with Klebsiella and E. coli bacteraemia had many common features, including a high incidence of neoplastic disease, biliary tract disease, and renal failure. Many had undergone surgery or received therapy with steroids, antacids or antibiotics. Klebsiella bacteraemia was more often found in males, in patients with hospital contact within the previous month, and polymicrobial infection. Logistic regression analysis showed that use of invasive plastic devices and diabetes were significantly associated with Klebsiella bacteraemia. The urinary tract was the commonest source, followed by the biliary tract; 27% of patients had no obvious focus of infection, and in many of these an invasive device may have been involved. Forty-five K-serotypes were found--the largest number being nine strains of type K3; only a few strains had acquired resistance characters to antimicrobial agents. There were no differences between community- and hospital-acquired strains; indicating that our hospital does not have a resident strain of Klebsiella.

Long-term prognosis of patients with surgical wound infections.

This study examined if surgical wound infections (SWI) result in a severe prognosis regarding general health and increase the consumption of social resources. A group of 1301 patients were interviewed by self-administered questionnaires during 1993-1994, while operated during hospitalization in seven Danish hospitals. These patients were followed up at least once by similar questionnaires at a median time of 5.5 and 10.0 months postoperatively. The consequences of surgically diagnosed SWI were analyzed in a hospital cohort of 58 infected patients and 648 controls. Postdischarge infections were analyzed in a patient cohort of 263 cases and 767 controls. Changes in health was measured by the General Health Questionnaire, Activities of Daily Living index, and self-assessed health. Consumption of resources were estimated by reliance on assistance from family and friends, use of home services, and contacts to doctors. It was found that the long-term prognosis of general health was unaffected by SWIs. However significantly increased social dependence was found for patients with SWIs compared to uninfected patients. Almost one-fourth of the operations were complicated by an SWI. Most of the infections were recognized only after discharge and were thought to be of minor importance, which may explain why no chronic impairment of the health was found for patients with an SWI. A bias toward no-effect may have been introduced if patients with severe SWIs abstained from participation. The societal cost of care for patients with minor infections seems to be large. The causal relation between outcome and SWI needs to be further investigated.

Evaluation of T cell subsets by an immunocytochemical method compared to flow cytometry in four countries.

The authors tested an alternative method for CD4 and CD8 T lymphocytes enumeration, the immunoalkaline phosphatase method (IA), in three African countries and in Denmark. The IA determinations from 136 HIV antibody positive and 105 HIV antibody negative individuals were compared to the corresponding results obtained by flow cytometry (FC) performed in the respective countries. The authors found good correspondence between the two methods for measurements of CD4 and CD8 T lymphocytes independent of serological status and geographical site. However, the CD4 and CD8 T lymphocytes values obtained by the two methods are not interchangeable as IA compared to FC consistently gives higher percentage of CD4 T lymphocytes, and lower percentage of CD8 T lymphocytes. Mean differences between the two methods did not differ between the three African countries indicating that the IA method provides systematic results. Replicate measurements suggested good correspondence between results obtained by IA. By using an IA level of < 300 CD4 T lymphocytes/microliter, the sensitivity was 81% and specificity 96% for detecting an FC level of < 200 CD4 T lymphocytes/microliter. Using an IA level of < 20% CD4 T lymphocytes, the sensitivity was 89% and specificity 95% for detecting an FC level of < 14% CD4 T lymphocytes. The FC and IA methods had the same internal correspondence between low absolute CD4 T cell count and low CD4 percentages; the sensitivity and specificity for detecting a low absolute CD4 T cell counts with a low CD4 percentage was 92% and 68% for FC and 91% and 73% for IA, respectively. The IA method is 10-fold cheaper than FC, is independent of advanced laboratory facilities, and does not need immediate processing of samples as blood smears can be stored for long periods. The IA method is therefore suitable for use in areas with limited resources and laboratory facilities where there is a need for immunological surveillance in hospital or community studies.

Comparison of two methods for enumerating malaria parasites in thick blood films.

Calculation of parasite densities is important for estimating herd immunity to malaria, and for determining end points in field trials for interventions such as malaria vaccines, impregnated bed nets, and chemosuppression. Two methods of enumeration were compared: method 1, in which 100 consecutive high-power fields (HPFs) are examined, and if they all contain at least one parasite, the number per field is then counted in 10-100 of these fields according to density; and method 2, in which the actual number of parasites present in 100 consecutive fields are counted. The first method significantly underestimates parasite density in samples in which less than all high-power fields are parasite-positive. A correction of method 1 is suggested, which results in a parasite density, which is comparable with that obtained using method 2. The correction factor estimated was 2(-In(1 - p)), where p is the proportion of positive HPFs. The correction factor presented will allow accurate estimate of parasite densities per volume of blood even if only the proportion of parasite-positive high-power fields containing at least one parasite are counted.

In vitro susceptibility of 124 Xanthomonas maltophilia (Stenotrophomonas maltophilia) isolates: comparison of the agar dilution method with the E-test and two agar diffusion methods.

The in vitro susceptibility of 124 Xanthomonas maltophilia isolates was tested by four methods: Agar dilution (reference method), E-test, a disk diffusion and a tablet diffusion method. Trimethoprim-sulfamethoxazole had the highest activity against X. maltophilia, followed by a combination of aztreonam-clavulanic acid at different ratios, the ratio 1:1 being the most active with a susceptibility rate of 85% as compared to 2% for aztreonam alone. Addition of the beta-lactamase inhibitor tazobactam to piperacillin enhanced the rate of susceptible isolates from 31% to 53%, Relatively few isolates were susceptible to ciprofloxacin (27%) and gentamicin (9%). Generally, the disk diffusion method had a considerably higher frequency of "very major" discrepancies when compared with the agar dilution method than with the other methods. The susceptibility of X. maltophilia to trimethoprim-sulfamethoxazole and ciprofloxacin could reliably be determined by all the diffusion methods tested, but otherwise the agar dilution method is to be preferred. A standardized and reliable diffusion method for susceptibility testing of X. maltophilia remains to be found. Trimethoprim-sulfamethoxazole must be considered the drug of choice in the treatment of severe X. maltophilia infections. The combination aztreonam-clavulanic acid is promising, but must be proved in a clinical setting.

Interval censored survival data and multistate compartmental models in the analysis of first appearance of Plasmodium falciparum parasites in infants.

A statistical model for interval censored data is described. Assuming a piecewise constant incidence enables us to analyse very unbalanced data in a generalized linear model. The distribution of age at first appearance of P. falciparum parasites in infants in Liberia has been estimated. A new graphical method for presentation of test results on all children was developed. In an illness--death model it is described how the proportion of undetected and detected malaria parasitemias depends on parasite rates and testing frequency. The incidence of detectable malaria parasitemia was 0.14 per month in infants under 4 months of age, and 0.60 per month in children over 4 months (p < 0.001). The congenital resistance to malaria in African infants living in a highly endemic area had largely disappeared by the age of 4 months; before this age children were partly protected.

Guinea pig cellular immune responses to proteins secreted by Mycobacterium tuberculosis.

To study the immunological activity of proteins secreted by Mycobacterium tuberculosis, we carried out comparative studies in guinea pigs infected intravenously with 2.5 x 10(3) CFU of this organism or with 2.5 x 10(4) CFU of Mycobacterium bovis BCG. Groups of infected guinea pigs were skin tested with fractions of secreted proteins covering well-defined narrow-molecular-mass regions, or such fractions were used for lymphocyte stimulation experiments. The lymphocyte stimulation experiments showed that the fraction containing proteins with molecular masses below 10 kDa had a superior stimulating capacity in tuberculous guinea pigs whereas the 24- to 30-kDa fraction gave significantly higher skin reactions in this group compared with BCG-vaccinated guinea pigs. A precise mapping within the region from 23 to 35 kDa by using a combination of narrow overlapping fractions and purified proteins enabled the identification of the 24-kDa antigen MPT64 as a molecule specific for tuberculous infection. Thus, MPT64 is a promising candidate for a specific diagnostic skin test reagent for human tuberculosis.

Firefly luciferase assay of adenosine triphosphate as a tool of quantitation of the viability of BCG vaccines.

The purpose of the present study was to compare conventional colony forming unit (CFU) enumeration with a bioluminescent measurement in order to quantitate living bacteria in BCG vaccine. Forty batches of BCG vaccine quantitated with respect to weight (10 each of concentration 120 mg/vial, 30 mg/vial, 1.5 mg/vial and 0.75 mg/vial, respectively) were tested. Adenosine triphosphate (ATP) was extracted using the boiling Tris-EDTA extraction method preceded by treatment with the ATP-hydrolysing enzyme apyrase, and the liberated ATP was assayed using a LKB 1251 luminometer. The sensitivity of the assay was 10(-11) M ATP which corresponded to 5 x 10(5) CFU/ml. A proportional relation between CFU and ATP content per vial was found up to 30 mg/vial, but for 120 mg/vial the CFU method seemed unreliable in contrast to the bioluminescence method. The measurements error for the logarithm (base 10) of ATP was 0.051 and this method was therefore more exact than the CFU method (0.097). Because the bioluminescence method is sensitive, reliable, time-saving and less expensive it seems preferable to CFU enumeration in the quality control of BCG vaccines.

Mortality rate and magnitude of Staphylococcus aureus bacteremia as assessed by a semiquantitative blood culture system.

A 4-year retrospective study ascertained the relation between the magnitude of Staphylococcus aureus bacteremia and mortality. 253 episodes of S. aureus bacteremia diagnosed in a Danish regional Department of Clinical Microbiology were included. Blood cultures were routinely done by inoculation of aseptically drawn blood into multiple tubes of bacteriological media. The rate of positive tubes was assumed to distinguish high- from low-grade bacteremia without providing an absolute count of colony forming units. The median number of tubes inoculated was 18 (range 6-48) with approximately 0.5-1 ml of blood per tube. The rate of positive tubes was related neither to the source of infection, i.e. whether the S. aureus infection was nosocomially or community-acquired, nor to the portal of entry. However, mortality increased with increasing rate: it was 18% for rates < 0.30, 23% for 0.30-0.69, 30% for 0.70-0.99, and 37% for a rate of 1.0. Thus, for S. aureus infections the magnitude of bacteremia seems to be a prognostic factor with possible bearings on clinical and therapeutic decisions.