Rune Andersson

EPIDEMIOLOGIC ASPECTS OF INFECTIVE ENDOCARDITIS IN AN URBAN POPULATION. A 5-YEAR PROSPECTIVE STUDY

A prospective study of the epidemiology of infective endocarditis (IE) in a well-defined urban population of 428,000 inhabitants during a 5-year period was carried out. All patients were treated in the same institution, and history, diagnostic procedures, and treatment were standardized. Of 233 consecutive suspected episodes of IE, 127 fulfilled the modified von Reyn criteria. After patients not living in the defined area were excluded, 99 episodes in 90 patients were analyzed in the epidemiologic part of the study. Of these, 33 episodes were definite endocarditis, verified by surgery or autopsy; 35 probable; and 31 possible endocarditis episodes. Another 34 episodes were found retrospectively and are included in the incidence calculation. The crude incidence was calculated to be 6.2/100,000 inhabitants per year, which is high compared to earlier studies. Adjusted to the population of Sweden, the incidence was 5.9/100,000 inhabitants per year. The annual incidence was higher for women, 6.6/100,000, than for men, 5.8/100,000. In the oldest age-group (80-89 years) the annual incidence was 22/100,000 in the prospective study and 30/100,000 if retrospective cases were included. Contrary to almost all other studies, we did not find a male predominance among our cases. Only 7% of patients were intravenous drug abusers, and 15% had a prosthetic valve. The most common bacteria were methicillin-susceptible Staphylococcus aureus (31%) and alpha-streptococci (28%); 12% of episodes were culture negative. The mortality from IE in the population was 1.4/100,000 inhabitants per year. A higher-than-expected incidence of IE was found, especially among older patients and women.

Cerebrovascular Complications in Patients with Left-Sided Infective Endocarditis Are Common: A Prospective Study Using Magnetic Resonance Imaging and Neurochemical Brain Damage Markers

Background. @nbsp; Cerebrovascular complications (CVCs) have remained a major therapeutic and prognostic challenge associated with infective endocarditis, and definite risk factors have not been fully elucidated. This prospective study was designed to the evaluate the total incidence of CVC associated with infective endocarditis and major risk factors. Methods. @nbsp; During 2 study periods, from June 1998 through April 2001 and from September 2002 through January 2005, patients were prospectively enrolled in the study regardless of neurological symptoms. Study patients underwent neurological examinations and magnetic resonance imaging of the brain, and cerebrospinal fluid analyses of inflammatory and neurochemical markers of brain damage (neurofilament protein and glial fibrillary acidic protein) were performed. Results. @nbsp; Sixty patients who experienced episodes of left-sided infective endocarditis were evaluated; 35% of these patients experienced a symptomatic CVC. Silent cerebral complications were detected in another 30% of the patients, and the total CVC rate was 65% (95% confidence interval, 58%-72%). Five percent of patients experienced their first neurological symptom after the initiation of antibiotic treatment without prior surgery. No new symptomatic CVCs were detected after 10 days of antibiotic treatment. No neurological deterioration was observed after surgery in patients who were established to have a symptomatic CVC preoperatively. A larger heart valvular vegetation size was a risk factor for both symptomatic and silent CVCs; Staphylococcus aureus etiology conferred a higher risk for symptomatic cerebral complication only. Conclusions. @nbsp; The use of sensitive methods of detection indicates that the incidence of CVC associated with infective endocarditis is high, but the risk for neurological deterioration during cardiac surgery after a CVC is lower than previously assumed. The major mechanism behind cerebral complications associated with infective endocarditis is cerebral embolization, although the dominant neurological symptoms vary considerably.

Vertebral osteomyelitis in Göteborg, Sweden: a retrospective study of patients during 1990-95.

Vertebral osteomyelitis (VO) is a rare condition and the diagnosis is often overlooked initially. Delay in diagnosis may result in vertebral destruction or perforation of the spinal canal. We suggest diagnostic criteria in order to simplify the diagnosis and classification of VO. Medical records of 58 patients with VO from Göteborg during the years 1990-95 were studied retrospectively. The incidence, clinical presentation, microbiology and treatment of VO were evaluated. The median age at the time of admission was 59 y (range 13-83 y) and the male:female ratio was 1.6:1. The incidence was 2.2/100,000 inhabitants/y. Sixty-four percent of the patients were natives of Sweden. The patients were classified as definite (67%), probable (26%) and possible (7%) VO. Staphylococcus aureus was the most common infective agent (34%), followed by Mycobacterium tuberculosis (27%). The most common risk factors included recent or current infections, immunosuppressive diseases and previous surgery. CRP and ESR were elevated in 82% and 88% respectively and plain X-ray changes indicating VO were found in 56% of the patients. Radiological changes were found in 34/44 (77%) computerized tomography scans and 10/13 (77%) magnetic resonance imaging examinations. The median duration of intravenous and oral antibiotic treatment were 10 and 179 d respectively. A delay of > I month from the onset of symptoms until diagnosis was found in 38% of the patients. This indicates the need for a standardized protocol for diagnosing VO. In this paper we suggest diagnostic criteria, which have not previously been available.Vertebral osteomyelitis (VO) is a rare condition and the diagnosis is often overlooked initially. Delay in diagnosis may result in vertebral destruction or perforation of the spinal canal. We suggest diagnostic criteria in order to simplify the diagnosis and classification of VO. Medical records of 58 patients with VO from Go¨teborg during the years 1990?95 were studied retrospectively. The incidence, clinical presentation, microbiology and treatment of VO were evaluated. The median age at the time of admission was 59 y (range 13?83 y) and the male:female ratio was 1.6 : 1. The incidence was 2.2/100,000 inhabitants/y. Sixty-four percent of the patients were natives of Sweden. The patients were classified as definite (67%), probable (26%) and possible (7%) VO. Staphylococcus aureus was the most common infective agent (34%), followed by Mycobacterium tuberculosis (27%). The most common risk factors included recent or current infections, immunosuppressive diseases and previous surgery. CRP and ESR were elevated in 82% and 88% respectively and plain X-ray changes indicating VO were found in 56% of the patients. Radiological changes were found in 34/44 (77%) computerized tomography scans and 10/13 (77%) magnetic resonance imaging examinations. The median duration of intravenous and oral antibiotic treatment were 10 and 179 d respectively. A delay of > 1 month from the onset of symptoms until diagnosis was found in 38% of the patients. This indicates the need for a standardized protocol for diagnosing VO. In this paper we suggest diagnostic criteria, which have not previously been available.

A clinical study of culture-negative endocarditis.

Culture-negative infective endocarditis (CNE) is a diagnostic problem in spite of improved echocardiographic and blood culturing techniques. We conducted the present study to estimate the proportion of CNE in patients with infective endocarditis, to investigate data regarding risk factors, and to evaluate the Duke and the modified Beth Israel criteria in patients with CNE.We evaluated 820 consecutive suspected episodes of infective endocarditis in adults at the Departments of Infectious Diseases in Göteborg and Borås, Sweden (1984–1996). All patients were diagnosed and treated according to a protocol; 487 episodes were identified as infective endocarditis. Episodes with absence of bacterial growth at blood culture were defined as CNE and were classified with the Duke and the modified Beth Israel criteria.We identified 116 CNE episodes (median age, 67 yr). Mortality was 7%, and in 15%, cardiac surgery was performed. The Duke criteria classified 20 definite, 80 possible, and 16 reject episodes. The modified Beth Israel criteria distinguished 13 definite, 15 probable, 27 possible, and 61 reject episodes. The proportion of CNE among patients with infective endocarditis varied from 19% to 27% at the 2 departments. Antibiotic treatment preceded blood culture in 45% of the CNE episodes.About 20% in a Scandinavian population of infective endocarditis patients have CNE. Antibiotic pretreatment explains less than 50% of all CNE episodes. The Duke criteria are more sensitive but less specific than the modified Beth Israel criteria in classifying patients with CNE.

The epidemiology of and risk factors for invasive Staphylococcus aureus infections in western Sweden

We conducted a prospective study of all cases of invasive Staphylococcus aureus infections (ISA) in the catchment area of Skaraborg Hospital (population 255,109) in western Sweden from March 2003 to February 2005. The annual incidence was 33.9 cases/100,000 population. Of these, 49% were classified as community-acquired, 32% as nosocomial and 19% as health care-associated. The mean age was 65 y. We registered children (age ≤18 y) in 13 episodes. The most common predisposing illnesses/conditions were persons undergoing haemodialysis (relative risk 291), peritoneal dialysis (relative risk 204), persons with rheumatoid arthritis (relative risk 9), diabetes mellitus (relative risk 8), and cancer (relative risk 7). The patients were treated at various departments; only 18% of the episodes were primarily cared for at a department of infectious diseases. The most common diagnosis was soft tissue infection (27% of the episodes), bacteraemia without focus (19%), arthritis (15%), and line-associated infection (14%). A total of 197 invasive isolates was obtained, the vast majority from blood, in 141 of 170 episodes. We documented the wide spectrum of signs and symptoms. One- quarter of the patients had no history of fever, and one-third of the bacteraemia patients had normal white blood cell count (<10×109/l) at presentation. All cases were of MSSA (methicillin-sensitive Staphylococcus aureus).

Pacemaker endocarditis during 18 years in Göteborg.

Pacemaker endocarditis is a rare but serious complication. Few studies addressing its treatment have been published. Clinical characteristics and outcome were retrospectively studied in 38 patients with 44 episodes of pacemaker infective endocarditis (PMIE) in Göteborg, during 1984–2001. The male/female ratio of episodes was 27/17 and the mean age 69 y. Transthoracic echocardiography (TTE) showed vegetation in 4/22 (18%) episodes and transoesophageal echocardiography (TEE) in 22/33 (67%). Staphylococci were isolated in 66% of blood cultures. The pacemaker system (PS) was removed in 28 episodes and in 18 of these there were no signs of reinfection at follow-up. In 16 episodes the PS was not removed, and in 13 of these, signs of infection were found at follow-up. Thus, the present study of PMIE showed staphylococci to be predominant causative agents and demonstrated a high diagnostic sensitivity of TEE. According to our results, PM removal rather than conservative treatment should be considered in all cases.

Antibody responses in patients with invasive Staphylococcus aureus infections.

Correlation between antibody response and clinical outcome in Staphylococcus aureus bacteremia has yielded conflicting results. Immunization schedules have failed in clinical trials. Is the humoral response toward S. aureus of protective nature? A prospective study was performed in patients with invasive S. aureus (ISA) infections during the period 2003–2005. The antibody levels were determined at the beginning and at the end of treatment and one month later (n = 96, n = 71, and n = 51, respectively). As controls, 115 healthy individuals were used. A quantitative enzyme-linked immunosorbent assay (ELISA) against eight purified antigens was performed. Bacterial isolates were grouped as to the production of alpha-toxin, agr type, and pulsed-field gel electrophoresis (PFGE) type. Large variations were seen in the antibody levels. The levels in the second sample were the highest. A correlation between agr group, PFGE group, alpha-toxin production, and initial antibody levels was observed. Patients with fatal outcome displayed lower initial antibody levels to all antigens and significantly so in regard to teichoic acid, lipase, enterotoxin A, and scalded skin syndrome toxin. In episodes with complicated bacteremia, initial significantly low levels to teichoic acid and lipase were registered. Low initial antibody levels against several antigens were associated with increased mortality and complicated bacteremia in invasive S. aureus infections. Bacterial properties, strain, and toxin production affected the antibody response.

Levels of Antibody against 11 Staphylococcus aureus Antigens in a Healthy Population

ABSTRACT Serum samples from 151 healthy individuals aged from 15 to 89 years were investigated by enzyme-linked immunosorbent assay (ELISA) for IgG levels against 11 different purified antigens from Staphylococcus aureus. Surface antigens, such as teichoic acid, clumping factors A and B, and bone sialoprotein binding protein, and extracellular proteins, such as alpha-toxin, lipase, enterotoxin A, toxic shock syndrome toxin, scalded-skin syndrome toxin, fibrinogen binding protein, and extracellular adherence protein, were used. The IgG values were analyzed in relation to the state of nasal carriage at the time of sampling. There was great individual variation in antibody levels in both young and elderly healthy subjects. Occurrence of S. aureus in the nares at the time of sampling was correlated with higher antibody levels, while elderly individuals over 65 years of age showed slightly lower levels than younger adults. More individuals than was expected from random probability calculations showed high antibody levels against several antigens, and more individuals than would be expected showed low levels against several antigens. Certain extracellular proteins had more often induced IgG levels of the same magnitude in the same individuals, indicating that among these individuals, there was a tendency to respond to certain antigens in the same way. Most individuals had circulating IgG antibodies to the 11 tested antigens, and some individuals had the tendency to be “good responders” to several antigens, while others were “poor responders.” These findings constitute basic knowledge for the development of improved serological diagnostics, immune prophylaxis, individual prognosis tools, and therapy against invasive Staphylococcus aureus infections.

C-reactive protein is more sensitive than erythrocyte sedimentation rate for diagnosis of infective endocarditis

SummaryThe objective of this study was to evaluate the sensitivity of C-reactive protein (CRP) elevation compared to erythrocyte sedimentation rate (ESR), leucocyte count and thrombocyte count in the diagnosis of infective endocarditis (IE). It was designed as a prospective study of suspected episodes of IE in adults in tertiary care at a university-affiliated department of infectious diseases. In 89 episodes of IE, CRP was available from the start of treatment. Median age was 66 years, 45 were men and 44 women. Median CRP concentration was found to be 90 (range 0–357) mg/l with only 4% normal values. Episodes involving native valves had higher CRP than episodes occurring with prosthetic valves. Staphylococcal origin, short duration of symptoms, short duration of fever and highest recorded temperature all correlated to higher CRP levels. The CRP response was also prominent among patients >70 years old. Among non-responders, a few cases with simultaneous cirrhosis were noted. ESR was less sensitive than CRP, with a normal level in 28% of the episodes. It was concluded that CRP determination is superior to erythrocyte sedimentation rate, leucocyte count and thrombocyte count in the diagnosis of infective endocarditis.The objective of this study was to evaluate the sensitivity of C-reactive protein (CRP) elevation compared to erythrocyte sedimentation rate (ESR), leucocyte count and thrombocyte count in the diagnosis of infective endocarditis (IE). It was designed as a prospective study of suspected episodes of IE in adults in tertiary care at a university-affiliated department of infectious diseases. In 89 episodes of IE, CRP was available from the start of treatment. Median age was 66 years, 45 were men and 44 women. Median CRP concentration was found to be 90 (range 0–357) mg/l with only 4% normal values. Episodes involving native valves had higher CRP than episodes occurring with prosthetic valves. Staphylococcal origin, short duration of symptoms, short duration of fever and highest recorded temperature all correlated to higher CRP levels. The CRP response was also prominent among patients >70 years old. Among non-responders, a few cases with simultaneous cirrhosis were noted. ESR was less sensitive than CRP, with a normal level in 28% of the episodes. It was concluded that CRP determination is superior to erythrocyte sedimentation rate, leucocyte count and thrombocyte count in the diagnosis of infective endocarditis.

HIV/AIDS Awareness, Attitudes and Risk Behavior Among University Students in Wuhan, China

Background: In China, the estimated number of HIV positives in 2007 was 700,000 and the epidemic continues to expand. Because of their attitudes towards sexual behavior, young people are considered to be a group at high risk. Methods: Eight hundred sixty-eight undergraduate students at Wuhan University were selected through stratified cluster sampling, to answer a questionnaire. They were divided into three main groups: Chinese medical students, foreign medical students and Chinese students from other faculties. Fourteen interviews were conducted in addition. Results: Ninety-nine percent of the students had heard of HIV/AIDS and 76% of the students could distinguish HIV from AIDS. The main route of transmission was believed by the Chinese students to be blood transfusion and sexual intercourse by the foreign medical students. The female students knew more about the routes of transmission than the male students. Medical students had a higher level of knowledge than non-medical students, and among the medical students, the foreign students were more knowledgeable than the Chinese students. Only 8 % of the students were sexually active. Conclusion: The students had an accepting attitude towards people living with HIV and no extensive risk behavior. Overall, the knowledge level was found to be moderate.