Staphylococcal bacteraemia. Clinical and bacteriological observations in 201 cases

Existing data sources for clinical epidemiology: The North Denmark Bacteremia Research Database

Bacteremia is associated with high morbidity and mortality. Improving prevention and treatment requires better knowledge of the disease and its prognosis. However, in order to study the entire spectrum of bacteremia patients, we need valid sources of information, prospective data collection, and complete follow-up. In North Denmark Region, all patients diagnosed with bacteremia have been registered in a population-based database since 1981. The information has been recorded prospectively since 1992 and the main variables are: the patient’s unique civil registration number, date of sampling the first positive blood culture, date of admission, clinical department, date of notification of growth, place of acquisition, focus of infection, microbiological species, antibiogram, and empirical antimicrobial treatment. During the time from 1981 to 2008, information on 22,556 cases of bacteremia has been recorded. The civil registration number makes it possible to link the database to other medical databases and thereby build large cohorts with detailed longitudinal data that include hospital histories since 1977, comorbidity data, and complete follow-up of survival. The database is suited for epidemiological research and, presently, approximately 60 studies have been published. Other Danish departments of clinical microbiology have recently started to record the same information and a population base of 2.3 million will be available for future studies.

Importance of focus identification in the treatment of Staphylococcus aureus bacteraemia

Staphylococcus aureus bacteraemia increases in frequency, and it is still a life-threatening disease. In recent years, some interesting studies such as the need for focus identification and the focus eradication have been performed. The aim of this review is to present an up-to-date assessment of the current challenges in the management of S. aureus bacteraemia in order to improve the outcome.

Retrospective study of outcome in patients treated for Staphylococcus aureus bacteremia

OBJECTIVE: To investigate whether a change in current treatment practice for Staphylococcus aureus bacteremia from flucloxacillin and aminoglycoside to flucloxacillin and fusidic acid was associated with any changes in outcome. METHODS: A retrospective analysis was carried out of 316 episodes of S. aureus bacteremia diagnosed and treated in a tertiary hospital complex between 1983 and 1993. Outcomes considered were (1) death related to the infection and (2) relapse following cessation of antibiotic therapy. RESULTS: Mortality related to infection, which occurred in 24% of patients, was unrelated to treatment with the combination of flucloxacillin and fusidic acid; however, increasing age was a significant risk factor (OR per decade=1.35, 95% CI=1.18-1.55), and increasing duration of treatment (OR per week of treatment=0.63, 95% CI=0.52-0.77), use of flucloxacillin (OR=0.30, 95% CI=0.14-0.64), presence of an intravascular device (OR=0.39, 95% CI=0.20-0.78) and presence of a skin lesion (OR=0.51, 95% CI=0.26-0.99) were significant protective factors. The only factor significantly related to relapse, which occurred in 11% of patients, was treatment with the combination of flucloxacillin and fusidic acid (OR=0.32, 95% CI=0.12-0.85). There was approximately a 70% reduction in the risk of relapse if this combination was used. CONCLUSIONS: This retrospective analysis suggests a clinically important protective effect of fusidic acid against relapse in patients with S. aureus bacteremia. Although the results were adjusted for potential confounding factors, the possibility of bias remains. There is a need for a prospective randomized trial to evaluate the effectiveness of flucloxacillin and fusidic acid for treating S. aureus bacteremia.

Epidemiology of Staphylococcus aureus bacteremia in Denmark

The number of Staphylococcus aureus bacteremia cases has increased annually in Denmark during the latest decades. This increase has occurred among older patients with hospital-acquired bacteremia. Methicillin-resistance, which earlier was a property of strains of the 83A phage-complex, has nearly disappeared, while the frequency of penicillin-resistance has increased. Today both the phage-type pattern and antibiotic resistance are nearly similar for strains from hospital-acquired and community-acquired cases. In hospitals the frequency of bacteremia after postoperative wound infections has decreased, while cases associated with intravascular catheters has increased, and these infections are now the most common cause of hospital-acquired S. aureus bacteremia. Endocarditis is most commonly found in community-acquired cases without an identified primary focus in patients between 21-50 years. Also hematogenous osteomyelitis is most common in community-acquired cases, but these infections have changed to having a high predilection for the vertebral column, and the prevalence of chronic cases has decreased.

Staphylococcus aureus bacteraemia: 400 episodes in St Thomas's Hospital

Four hundred episodes of Staphylococcus aureus bacteraemia occurred in St Thomas's Hospital from 1969 to 1983, accounting for 17.5% of all episodes of bacteraemia. The mortality was 24%, half attributable to underlying disease, and was highest in patients over 50. Almost 60% of the bacteraemias were acquired in hospital, and the source of the organism was generally obvious, with vascular access sites the most common (37%). Bone and joint infections accounted for 11.5% of episodes and endocarditis for 7%. Most staphylococci were resistant to penicillin only; three isolates were resistant to methicillin and five to fusidic acid. Microbiologists seldom influenced directly the choice of initial antibiotic treatment (though this usually conformed to the hospital's antibiotic prescribing policy) but had considerable influence over definitive treatment, usually cloxacillin or flucloxacillin alone or in combination with fusidic acid. S aureus bacteraemia is easy to identify and treat, though underlying disease may influence the outcome. Efforts should be made to prevent the largely iatrogenic disease.

Metastatic infection secondary to genitourinary tract sepsis

Metastatic infections arising from sepsis in the genitourinary tract are reviewed in 175 cases, including five in which we treated the patients. The skeleton was the most common site of metastasis (59 per cent). The endocardium was next most frequently involved (28 per cent). Gram-negative organisms were implicated in less than two-thirds of the cases (59 per cent). Impaired host defense mechanisms were noted in 25 per cent of the patients experiencing metastatic infections. The lower urinary tract was the source of metastasis in 75 per cent of the patients, particularly after urologic manipulation in men. Women were more likely to experience metastatic infection from the upper urinary tract. Anatomic and pathologic considerations explaining these sex differences are presented.

Staphylococcus aureus bacteremia. Current clinical patterns

One hundred and five cases of bacteremia due to Staphylococcus aureus were reviewed to assess the current clinical spectrum of serious staphylococcal disease. Mortality was 21 percent, lower than previously reported. Patients could be separated into two groups according to the presence of identifiable primary staphylococcal infections; 63 bacteremic patients had such lesions, the remaining 42 lacked them. The latter group contained 24 of 26 cases of endocarditis. Illnesses in that group were marked by the presence (in 38 of 42 patients) of staphylococcal foci occurring secondary to bacteremia. Such foci were responsible for five of seven instances of relapse or treatment failure encountered in that group. Secondary staphylococcal foci occurred in only five of 63 patients with primary infections, and the response of this group to conventional therapy for bacteremia was satisfactory. This study suggests that endocarditis has become an unusual complication of identifiable primary staphylococcal infection. A clinical classification based on the presence of such lesions therefore separates bacteremic patients likely to be cured by conventional antibiotic therapy (those with primary infections but no secondary foci) from others (those with secondary foci, suggesting endocarditis) who should receive a more prolonged course of antibiotics.

An unusual case of spontaneous bacterial myositis

A further report of spontaneous bacterial myositis occurring in the British Isles is recorded. The case is unusual because both calf muscle compartments were simultaneously affected, and unique in that surgical decompression was required to prevent impending limb ischaemia.

Some bacteraemias encountered in hospital practice

This is a retrospective study of the results of 4,642 blood cultures taken from 2,190 patients from 1960 to 1967 in one London hospital. The results suggested that an increased incidence of bacteraemias at this particular hospital was mainly due to the increase in the number of patients having blood cultures. Some of the bacteraemias were terminal or transient and probably of doubtful clinical significance.

Etiology of bacteremia

Blood-culture results for a 15-year period from a large southern hospital were tabulated and analyzed for alterations in the bacterial species associated with bacteremia. From 15,543 cultures, 2,410 positive cultures (15.6%) were obtained. These results were grouped into 5-year periods, and an alteration in the incidence of the agents was demonstrated. In the past 5 years, gram-negative bacilli have replaced gram-positive cocci as the most common agents of bacteremia, and several species not formerly associated with septicemia were found to be involved in a large number of cases. The importance of the clinical laboratory monitoring blood culture results was demonstrated as was the need for constant collaboration between the clinician and microbiologist.