Chlamydia pneumoniae IgG and IgA antibody titers and prognosis in patients with coronary heart disease: results from the CLARICOR trial

The association observed between coronary heart disease (CHD) and Chlamydia (Chlamydophila) pneumoniae antibodies prompted, during the 1990s, several primary and secondary prevention trials with various antibiotics. In our CLARICOR trial, a randomized placebo-controlled trial in 4372 patients with stable CHD, a brief clarithromycin regimen was followed, unexpectedly, by increased long-term mortality. We now compare C. pneumoniae antibody levels at entry with population levels, with the patients' individual histories, and with their subsequent outcomes. IgG antibody levels were somewhat raised, but elevated IgA and IgG titers were unrelated to entry data (including prior acute myocardial infarction), except for an association with smoking and with not using statins. Hazards of mortality and of other outcomes tended to slightly increase with IgA and decrease with IgG titers, but the unfavorable clarithromycin effect was unrelated to antibody levels and remains unexplained. Smoking-related lung disease probably underlies the link between heart disease and increased IgG titers.

A flow chamber assay for quantitative evaluation of bacterial surface colonization used to investigate the influence of temperature and surface hydrophilicity on the biofilm forming capacity of uropathogenic Escherichia coli

We have established a simple flow chamber-based procedure which provides an accurate and reproducible way to measure the amount of biofilm formed on an implantable biomaterial surface. The method enables the side-by-side evaluation of different materials under hydrodynamic flow conditions similar to those found on an implanted device. We have used the method to evaluate the biofilm forming capacity of clinically isolated Escherichia coli on silicone rubber and on silicone rubber containing a hydrophilic coating. It was found that the surface chemistry influenced the colonization of the isolates very differently. In addition, the temperature was found to have a considerable influence upon the adhesion and biofilm forming capacity of some of the isolates, and that the influence of surface chemistry depended on temperature. Our results suggest that the step from using E. coli laboratory strains to clinical isolates entails a significant rise in complexity and yields results that cannot be generalized. The results should be valuable information for researchers working with pre-clinical evaluation of device-associated E. coli infections.

The epidemiology of febrile reactions in haemodialysis

Febrile reactions were studied in 2 000 consecutive haemodialyses performed in 85 patients. A number of 219 febrile reactions were registered in 49 patients (11%). The overall month-to-month incidence showed little variation. Febrile reactions were not distributed randomly among the patients; those with respiratory tract infection experienced more febrile reactions during periods with infection than during periods without. Similarly, the incidence was higher in patients with than without chronic urinary tract infection. A low incidence was registered both in patients under 40 years of age and in patients having had more than 100 dialyses at the beginning of the observation period. The frequency was the same whether single-pass or recirculating single-pass monitors had been used, and it was not influenced by blood transfusions during dialysis. Thus, our analysis leads to the conclusion that the majority of the febrile reactions registered among the present patients were determined by endogenous factors such as infection, while exogenous factors such as dialysate bacteria and pyrogens seem to have played only a minor role.

[Dispersal of Staphylococcus aureus from nasal carriers]

INTRODUCTION

Staphylococcus aureus (Sa) is an important cause of hospital-acquired infections, and nasal carriage of Sa is common among health care workers. This study was designed to measure the airborne dispersal of Sa and other bacteria from such carriers and to investigate whether the use of cap, gown, gloves, and mask could reduce this dispersal.

MATERIAL AND METHODS

A total of 13 nasal Sa carriers were identified among 63 persons screened for Sa nasal carriage. The volunteers were studied for airborne dispersal of Sa in four different situations: quiet breathing, movements of the arms, whispering and loud talking. These activities were performed with and without gown, gloves, mask and cap upon street clothes.

RESULTS

The study showed that the highest number of Sa and bacteria in total was dispersed into the air when the volunteers were moving and wearing only their street clothes. The dispersal of Sa into the air was reduced into a minimum by wearing cap, gown and gloves, and no further significant decrease was achieved by wearing a mask. This applied for all volunteers except for one, who had to wear a mask in order to reduce his dispersal of Sa to a minimum. The total dispersal of bacteria was significantly reduced by wearing cap, gown and gloves; however, to reduce this dispersal to a minimum, volunteers also had to wear a mask.

CONCLUSION

Our study supports the rational basis that gown, cap, gloves and mask should be used not only in the operating theatre, but also while e.g. inserting central venous catheters.

Reversal of methicillin resistance in Staphylococcus aureus by thioridazine

OBJECTIVES

Thioridazine has been shown to reverse oxacillin resistance in methicillin-resistant Staphylococcus aureus (MRSA) in vitro. The aim of this study was to investigate whether thioridazine alone or in combination with oxacillin affects the transcription of the methicillin resistance gene mecA and the protein level of the encoded protein PBP2a.

METHODS

Viability of MRSA was determined in liquid media in the presence of oxacillin or thioridazine alone or in combination. Transcription of mecA was analysed by primer extension, and the protein level of PBP2a was analysed by western blotting in the presence of thioridazine and oxacillin.

RESULTS

We observed an increased susceptibility of MRSA towards oxacillin in the presence of thioridazine compared with bacteria grown with oxacillin or thioridazine alone. Transcription of mecA was reduced with increasing concentrations of thioridazine in the presence of a fixed amount of oxacillin. Furthermore, the protein level of PBP2a was reduced when bacteria were treated with the combination of oxacillin and thioridazine. The two drugs also affected the mRNA level of the beta-lactamase gene, blaZ.

CONCLUSIONS

The present study indicates that reversal of methicillin resistance by thioridazine in MRSA may be explained by a reduced transcription of mecA and blaZ, resulting in a reduced protein level of PBP2a.

Clarithromycin for 2 weeks for stable coronary heart disease: 6-year follow-up of the CLARICOR randomized trial and updated meta-analysis of antibiotics for coronary heart disease

OBJECTIVES

We have reported increased 2.6-year mortality in clarithromycin- versus placebo-exposed stable coronary heart disease patients, but meta-analysis of randomized trials in coronary heart disease patients showed no significant effect of antibiotics on mortality. Here we report the 6-year mortality of clarithromycin- versus placebo-exposed patients and updated meta-analyses.

METHODS

Centrally randomized, placebo controlled multicenter trial. All parties were blinded. Analyses were by intention to treat. Meta-analyses followed the Cochrane Collaboration methodology.

RESULTS

We randomized 4,372 patients with stable coronary heart disease to clarithromycin 500 mg (n = 2,172) or placebo (n = 2,200) once daily for 2 weeks. Mortality was followed through public register. Nine hundred and twenty-three patients (21.1%) died. Six-year mortality was significantly higher in the clarithromycin group (hazard ratio 1.21, 95% confidence interval 1.06-1.38). Adjustment for entry characteristics (sex, age, prior myocardial infarction, center, and smoking) did not change the results (1.18, 1.04-1.35). Addition of our data to that of other randomized trials on antibiotics for patients with coronary heart disease versus placebo/no intervention (17 trials, 25,271 patients, 1,877 deaths) showed a significantly increased relative risk of death from antibiotics of 1.10 (1.01-1.20) without heterogeneity.

CONCLUSIONS

Our results stress the necessity to consider carefully the strength of the indication before administering antibiotics to patients with coronary heart disease.

[The importance of hygiene for hospital infections]

Hospital cleaning is a neglected part of infection control. Due to financial constraints and lack of clinical evidence it has been cut down to the bare minimum and currently-used methods are unfit for the removal of microorganisms. Recent studies indicate that MRSA and other important pathogens may be transmitted to patients from the hospital environment. Furthermore, studies suggest that intensified cleaning may lower the risk of transmission. There is an urgent need for more clinical evidence and for development of standards and methods which focus on the removal of pathogens from the hospital environment.

[Costs attributed to hospital-acquired infections]

The literature on costs associated with hospital-acquired infections is critically evaluated and exemplified. There are considerable added costs attributed to hospital infections. Two types of analyses are discussed: cost-of-illness studies, COIs, typically without a societal cost perspective, and cost-effectiveness studies. It is a mistake to think that costs calculated in COIs can be used as estimates of potential savings in cost-effectiveness analyses. As a general rule, this is not the case. The calculation of unit costs and marginal costs are common weaknesses in most studies.

[Hospital infections: sources and routes of infection]

Hospital infections arise by autoinfection from patients' endogenous flora, by cross infection from other patients and hospital staff, and by transmission of pathogens from items in the hospital environment. Organisms may be transmitted by direct and indirect contact, by the airborne route, and with water, food and drugs. This review details the more important routes of infection, highlighting among others the role of Staphylococcus aureus carriage in patients and staff, issues related to disinfection of endoscopes, and the risk of transmitting blood-borne viruses with multidose vials.

Detection and identification of Anaplasma phagocytophilum, Borrelia burgdorferi, and Rickettsia helvetica in Danish Ixodes ricinus ticks

Borreliosis is an endemic infection in Denmark. Recent serosurveys have indicated that human anaplasmosis may be equally common. The aim of this study was to look for Anaplasma phagocytophilum and related pathogens in Ixodes ricinus ticks and estimate their prevalence, compared to Borrelia, using PCR. Ticks were collected from three locations in Denmark: Jutland, Funen, and Bornholm. Ticks from Jutland and Funen were analysed individually, ticks from Bornholm were analysed in pools of 20. A. phagocytophilum was found in ticks from all areas. A. phagocytophilum was found in 23.6% of ticks from Jutland and Funen, while 11% were positive for Borrelia burgdorferi. The Borrelia genotype B. afzelii was most prevalent, followed by B. valaisiana, B. burgdorferi s.s. and B. garinii.A. phagocytophilum was found in 14.5% of nymphs and 40.5% of adult ticks, while Borrelia was found in 13% of nymphs and 8% of adult ticks. The difference in prevalence between Anaplasma and Borrelia in adult ticks supports the idea that their maintenance cycles in nature may be different. Ticks were also infected with Rickettsia helvetica. Our study indicates that A. phagocytophilum prevalence in ticks in Denmark is as high as Borrelia prevalence and that human anaplasmosis may be unrecognized.

Panum's studies on "putrid poison" 1856. An early description of endotoxin

In 1855-1856 the Danish physiologist, Peter Ludvig Panum (1820-1885) performed a series of remarkable experiments on "putrid poison", a hypothetical substance claimed to be responsible for the symptoms and signs seen in patients with sepsis. Dogs were given intravenous infusions of putrefying solutions, and symptoms and signs were recorded. Infusion of a suitable amount resulted in characteristic sepsis symptoms and signs, which only started after a delay of half an hour. By modifying his test solutions Panum could show that the toxic principle was a solid substance, soluble in water, but insoluble in alcohol, and with preserved activity after long-term boiling. "Putrid poison" has striking similarities with endotoxin, a cell wall product of Gram-negative bacteria and a powerful inducer of inflammation and septic shock. Thanks to Panum's carefully arranged experiments and meticulous recording of observations it is fair to conclude that "putrid poison" was endotoxin, and as such he deserves credit for being the first to have described endotoxin. Panum published his observations twice, in Danish in 1856, and in German in 1874. At first he rejected the possibility that bacteria could play a causative role in the development of symptoms and signs seen after infusion of "putrid poison". However, in his last publication he hypothesized that "putrid poison" could be a bacterial product, and he envisaged future antibacterial chemotherapy of sepsis and treatment with anti-endotoxin agents.

Randomised placebo controlled multicentre trial to assess short term clarithromycin for patients with stable coronary heart disease: CLARICOR trial

OBJECTIVE

To determine if the macrolide clarithromycin affects mortality and cardiovascular morbidity in patients with stable coronary heart disease.

DESIGN

Centrally randomised multicentre trial. All parties at all stages were blinded. Analyses were by intention to treat.

SETTING

Five Copenhagen University cardiology departments and a coordinating centre.

PARTICIPANTS

13,702 patients aged 18 to 85 years who had a discharge diagnosis of myocardial infarction or angina pectoris in 1993-9 and alive in August 1999 were invited by letter; 4373 were randomised.

INTERVENTIONS

Two weeks' treatment with clarithromycin 500 mg/day or matching placebo.

PRIMARY OUTCOME

composite of all cause mortality, myocardial infarction, or unstable angina pectoris during three years' follow-up. Secondary outcome: composite of cardiovascular mortality, myocardial infarction, or unstable angina pectoris. The outcomes were obtained from Danish registers and were blindly assessed by the event committee.

RESULTS

2172 participants were randomised to clarithromycin and 2201 to placebo. We found no significant effects of clarithromycin on the primary outcome (hazard ratio 1.15, 95% confidence interval 0.99 to 1.34) or secondary outcome (1.17, 0.98 to 1.40). Mortality was significantly higher in the clarithromycin arm (1.27, 1.03 to 1.54; P = 0.03) as a result of significantly higher cardiovascular mortality (1.45, 1.09 to 1.92; P = 0.01).

CONCLUSIONS

Short term clarithromycin in patients with stable coronary heart disease may cause significantly higher cardiovascular mortality. The long term safety of clarithromycin in patients with stable ischaemic heart disease should be examined. Trial registration ClinicalTrials.gov NCT00121550.

In vitro Activity of Phenothiazine Derivatives in Enterococcus faecalis and Enterococcus faecium

The antimicrobial activity of the phenothiazine derivatives thioridazine and prochlorperazine have been evaluated with 11 Enterococcus faecalis strains and 9 Enterococcus faecium strains, originating from human infections and animal faecal flora. We found that all E. faecalis and E. faecium strains, regardless of their susceptibility to commonly used antibiotics, were inhibited by thioridazine at a concentration of 16-32 microg/ml and by prochlorperazine at a concentration of 32-64 microg/ml. Combinations of the antibiotics vancomycin or ampicillin and thioridazine and prochlorperazine at subinhibitory concentrations, could render vancomycin- or ampicillin-resistant bacteria sensitive to each of the antibiotics. Verapamil and reserpine, inhibitors of P-glycoprotein-mediated multidrug resistance, did not reduce resistance. Our results outline modification of resistance in enterococci induced by phenothiazine derivatives unrelated to P-glycoprotein-mediated multidrug resistance.

Large-scale testing of women in Copenhagen has not reduced the prevalence of Chlamydia trachomatis infections

OBJECTIVE

To examine the impact of a stable, large-scale enzyme immunoassay (EIA) Chlamydia trachomatis testing situation in Copenhagen, and to estimate the impact of introducing a genomic-based assay with higher sensitivity and specificity.

METHODS

Over a five-year study period, 25 305-28 505 women screened for chlamydial infection each year, corresponding to 19.3% of the female population in Copenhagen, Denmark, were analyzed.

RESULTS

The C. trachomatis age-specific examination percentage and age-specific positive percentage were unchanged during the study period. For EIA, the age-specific positive predictive value of a test decreased from 94% at age 17 to only 50% at age 34 years. Irrespective of the choice of diagnostic test, only about 30% of chlamydial infections would be diagnosed, given current strategies.

CONCLUSION

Although genomic detection assays will increase the positive and negative predictive values of the Chlamydia test result, new screening strategies for both men and women in younger age groups will be necessary if chlamydial infections are to be curtailed.

Beta-hemolytic streptococcal bacteremia: a review of 241 cases

Bacteremia with beta-hemolytic Streptococci groups A, B, C and G has a mortality rate of approximately 20%. In this study we analyzed the association of various patient risk factors with mortality. Records from 241 patients with beta-hemolytic streptococcal bacteremia were reviewed with particular attention to which predisposing factors were predictors of death. A logistic regression model found age, burns, immunosuppressive treatment and iatrogenic procedures prior to the infection to be significant predictors of death, with odds ratios of 1.7 (per decade), 19.7, 3.6 and 6.8, respectively. In bacteremic patients with erysipelas, mortality increased from 8% to 50% when bullae were observed. No HIV-positive patients or IVDUs died as a result of their bacteremic episode. Surprisingly, we found 49% resistance to tetracycline.

Klebsiella typing: pulsed-field gel electrophoresis (PFGE) in comparison with O:K-serotyping

OBJECTIVE

To compare pulsed-field gel electrophoresis (PFGE) typing and O:K-serotyping of Klebsiella in two different epidemiological settings.

METHODS

One hundred and four bacteremia isolates without known epidemiological relation and 47 isolates from an outbreak in a neonatal intensive care unit (NICU) were K-typed by countercurrent immunoelectrophoresis (CCIE), O-typed by an inhibition enzyme-linked immunosorbent assay method, and typed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI.

RESULTS

Typing data for the 104 bacteremia isolates were compared with regard to typability, number of types, maximum number of isolates per type, and the Discriminative Index (DI). O-typing combined with K-typing (DI 0.98) as O:K-serotyping (DI 0.99) gave a very discriminative typing system, whereas O-typing alone was not very discriminative (DI 0.76). PFGE (DI 1.00) was a more discriminative typing method than O:K-serotyping, as it could subdivide 13/22 O:K-serotypes into smaller groups. Isolates with the same PFGE-type had the same O:K-serotype, indicating that isolates with different O- and/or K-types could be expected to be of different PFGE-types. Typing of the 47 isolates from the outbreak in the NICU showed that 38 isolates belonged to a single clone, and that during an epidemic limited in time and space, differences in the electrophoretic patterns of up to five bands between a parental pattern type and a subtype may be found in the PFGE profiles.

CONCLUSIONS

Both O:K-serotyping and PFGE typing are highly discriminative typing methods. PFGE is the most discriminative method and is excellent for typing outbreaks with few isolates. If large numbers of isolates are to be typed, a more convenient strategy might be first to K- or O:K-serotype isolates followed by PFGE typing of possible identical isolates. Since K- or O:K-serotyping is a definitive typing method, while PFGE typing is a comparative one, PFGE cannot, for the time being, replace O:K-serotyping for surveillance purposes.

Role of the clinical microbiology laboratory in infection control--a Danish perspective

Clinical microbiology laboratories in Denmark are located in hospitals and staffed by clinical microbiologists who are clinically trained medical doctors. Each county has its own clinical microbiology unit, serving a population of 0.3-0.6 million. The responsibilities of clinical microbiology unit cover many different aspects of infection control. They include detection of outbreaks of hospital-acquired infections, screening for multi-resistant organisms, advice to clinicians about disinfection, sterilization and isolation procedures, and the rational use of antibiotics. Clinical microbiologists work closely with infection control nurses. Together they form the infection control team, which is the executive part of the local infection control committee. The infection control team is also the main body responsible for the development of guidelines, which are approved by the regional infection control committee. The local microbiology laboratories work in close contact with the National Department of Hospital Hygiene and other reference laboratories at the State Serum Institute. The present structure of infection control was established 25 years ago. The main aim at that time was to decentralize infection control and establish facilities as close to clinicians and patients as practically possible. This has solved most basic problems related to infection control, and compliance by clinicians has been fairly good. However, the present organization will not meet future requirements for standardization and documentation of quality. Currently a national standard for infection control is being prepared. It consists of a main standard defining requirements for the management system and 12 subsidiary standards defining requirements for specific areas of infection control. Adoption of the standard will undoubtedly require additional resources for infection control at a local level, and some organizational changes may also be needed. Infection control should be maintained as an integrated part of clinical microbiology.