Hanna Konisberger

Bacteremia in Adult Diabetic Patients

objective To compare the microbiology, sources, complications, and outcome of bacteremia in diabetic and nondiabetic patients. Research Design and Methods A prospective study was conducted of all episodes of bacteremia in hospitalized diabetic and nondiabetic patients. The study consisted of patients ≥ 18 yr of age with bacteremia detected within a 19-mo interval. Results We compared 124 episodes of bacteremia in 119 diabetic patients to 508 episodes in 480 nondiabetic patients. Diabetic patients were older than nondiabetic patients (median age 74 vs. 68 yr, P = 0.0001). In patients with an indwelling urinary catheter and bacteremic urinary tract infection, the percentage of Klebsiella in diabetic patients was 60% (6 of 10) and in nondiabetic patients was 17% (4 of 23, P = 0.04). In patients without an obvious source of bacteremia, the percentage of staphylococcal isolates in diabetic patients was 29% (10 of 35) and in nondiabetic patients was 14% (24 of 176, P = 0.04). Staphylococci were a common cause of bacteremic infections of the extremities in diabetic patients (12 of 19, 63%) and nondiabetic patients (20 of 50, 40%). Septic shock was the only complication that was more common in diabetic patients. The mortality in diabetic and nondiabetic patients was 28 and 29%, respectively. Conclusions Our results represent elderly patients with non-insulin-dependent diabetes mellitus. In this group, empirical treatment for suspected bacteremic urinary tract infection in patients with a urinary catheter should include coverage for Klebsiella. Empiric treatment for suspected bacteremia of unknown origin or caused by infection of the extremities should include an antistaphylococcal drug. The prognosis of bacteremia in diabetic and nondiabetic patients was similar.

Five-year prospective study of bacteraemic urinary tract infection in a single institution

In order to determine the epidemiology, microbiology, and outcome of bacteraemia originating in the urinary tract in hospitalised patients, a prospective study was conducted in a large general hospital in Israel. Data from all patients with bacteraemia were collected prospectively, and a subgroup of patients with bacteraemia secondary to urinary tract infection was analysed. There were 702 episodes of bacteraemia secondary to urinary tract infection during a five-year period (33.9% of all episodes of bacteraemia). The mean age of the patients was 76 years, and the male: female ratio was 0.9∶1.0. The most common pathogens wereEscherichia coli (52%),Klebsiella spp. (14%), andProteus spp. (9%).Pseudomonas spp. were isolated from 8% of all patients, from 19% of those who had received antibiotics, and from 15% of males.Enterococcus spp. were isolated from 4% of males but from no females. Five percent of the episodes were polymicrobial, and 16% of the infections were hospital acquired. On logistic multivariate regression analysis, predictors of mortality were: hospitalisation in a medical department, hospital-acquired infection, inappropriate empiric antibiotic treatment, presence of decubitus ulcer(s), respiratory or renal failure, and elevated urea and decreased albumin levels.

Patients at risk for inappropriate antibiotic treatment of bacteraemia

Abstract. In order to define patients at high risk for inappropriate antibiotic treatment of bacteraemia, we compared 682 bacteraemic patients, treated with an antibiotic drug to which the infecting micro‐organism was susceptible, with 419 patients who were inappropriately treated. On a multivariate logistic regression analysis including only clinical variables, four factors were found to be both significantly and independently associated with inappropriate antibiotic treatment: hospital‐acquired bacteraemia (oddsratio (OR) of 1.9), antibiotic treatment in the month prior to the bacteraemia (OR 1.9), residence in a nursing home (OR 1.8), and the presence of a central line (OR 1.7). A second model, including bacteriological data, showed four micro‐organisms to be independently associated with inappropriate antibiotic treatment: Candida sp. (OR 14.2), Acinetobacter sp. (OR 5.0), Enterococcus sp. (OR 3.6) and Pseudomonas sp. (OR 2.2). In this model, only two clinical features were included: hospital‐acquired infection and previous antibiotic treatment. Special efforts should be made to improve empirical antibiotic treatment in the groups defined above, and to facilitate early laboratory diagnosis of the micro‐organisms associated with inappropriate treatment.

Prediction of mortality in patients with bacteremia : The importance of pre-existing renal insufficiency

Pre-existing renal insufficiency serves as a common risk factor in the development of acute renal failure. Acute renal failure is a common finding in patients with bacteremia and is associated with poor prognosis. A total of 2722 consecutive patients 18 years old or older, fulfilling strike criteria of bacteremia or fungemia were prospectively evaluated to establish the prognostic importance of pre-existing renal insufficiency in bacteremic patients. They were classified according to serum creatinine levels upon admission into three groups. 915 patients had normal creatinine levels (≤ 1.0 mg/dL), 1528 had mild to moderate renal failure (creatinine 1.1–3 mg/dL) and 279 patients had severe renal failure upon admission (creatinine >3.0 mg/dL). Mild to severe renal failure upon admission was associated with old age, male gender, diabetes mellitus, ischemic heat disease, hypertension and congestive heart failure. The serum albumin in patients with severe renal failure was significantly low, with a mean of 2–9 mg/dL. Urinary tract infections were more prevalent in patients with mild to severe renal failure, while intravenous line infections, bacterial endocarditis and soft and skin tissue infections were more common in patients with normal renal function. In the 279 patients with severe renal failure the mortality rate was significantly higher (50%) compared to patents with mild to moderate renal failure and patients with normal renal function (21% and 26% respectively, p = 0.0001). Multiple regression analysis revealed that pre-existing serum creatinine >3 mg/dL was significantly associated with death attributable to bacteremia (OR=1.7, 95% CI 1.0–2.7). In conclusion, adult bacteremic patients with pre-existing serum creatinine above 3 mg/dL upon admission are at increased risk of mortality due to bacteremia than patients with normal or mild to moderate renal failure.

Bacteremia in Patients Without Known Underlying Disorders

Of 2030 consecutive patients with bacteremia, only 102 were free from underlying disorders. 43 were males, and the median age was 66 years. The sources of infection were the urinary tract (in 48%), lower respiratory tract (13%), endocarditis (7%), biliary tract (6%) and the meninges (5%). The most common pathogens were Escherichia coli (in 45% of patients), Streptococcus pneumoniae (21%), Staphylococcus aureus (9%) and hemolytic streptococci (9%). Overall mortality rate was 13%, 4% in patients with urinary tract infection and 19% in patients with other sources. Half of the deaths occurred within 2 days of hospitalization, and 75% of them within 4 days. All patients with septic shock and all patients with meningitis died. Other factors related to mortality were residence in a nursing home, low functional capacity, advanced age, high blood urea nitrogen and creatinine and low albumin, and infections caused by Staphylococcus aureus, Neisseria meningitidis and polymicrobial infections. A protective effect of appropriate antimicrobial antibiotic therapy could not be demonstrated. In conclusion, bacteremic patients with no known underlying disorder and source of their infection other than the urinary tract should be given maximum supportive treatment and should be closely watched.

Patterns of multiple resistance to antibiotics in gram-negative bacteria demonstrated by factor analysis

Principal component analysis was used to demonstrate the main associations between patterns of resistance to antibiotic drugs in 670 gram-negative bacteria consecutively isolated from blood cultures over a period of two years. Six factors were derived, which accounted for 84 % of the total variance of the original matrix. Each factor represented an association between resistance to certain antibiotics as follows: factor 1: aztreonam, third generation cephalosporins and aminoglycosides; factor 2: first and second generation cephalosporins; factor 3: tetracycline and chloramphenicol; factor 4: ampicillin and ureidopenicillins; factor 5: trimethoprim/sulfamethoxazole; factor 6: fluoroquinolones. On two-way analysis of variance the difference in the factor scores was significant between bacteria for all factors except factor 5. The difference in factor scores between community and hospital acquired strains was significant only for factors 1, 2 and 6. Only the score of factor 6 showed a clear trend to increase with time during the two-year study period. Patients who were treated with antibiotics prior to bacteremia had higher scores for all factors, the difference being most marked in patients treated with fluoroquinolones. Factor analysis can be used to describe phenotypic associations between resistance to antibiotics, and the factor score used to compare groups of isolates and to demonstrate temporal and other trends.