colistin and Thrombocytopenia

Acinetobacter species are not considered skin commensals and under-treatment is an overriding concern when caring for critically-ill patients who are mostly at risk of extensively drug-resistant Acinetobacter baumannii (XDRAB) infections. Hence even a single blood culture yielding XDRAB will tend to prompt intervention. However, field observations suggest that patients with single-positive blood cultures had milder disease and were more likely to be recruited in interventional studies than those with multiple-positive blood cultures, yet no distinction is made in current clinical or trial recruitment practices. To our knowledge, this is the first study to compare the clinical characteristics and outcomes of patients with single-positive versus multiple-positive blood cultures for XDRAB. In this multicenter prospective cohort study of XDRAB bacteremic patients from July 2010 to June 2015, only patients with at least two simultaneously drawn blood cultures were included. The patients were classified as having single-positive or multiple-positive blood cultures according to the number of positive blood cultures yielding XDRAB. The primary end-point was the 28-day mortality. Of a total of 155 patients enrolled, 69 had a single-positive and 86 had multiple-positive blood cultures. Leukopenia (37.2% vs. 16.2%; P = 0.004), thrombocytopenia (56.0% vs. 26.5%; P < 0.001), higher Pitt bacteremia scores (6.6 vs. 5.5, P = 0.03) and higher 28-day mortality rates (70.9% vs. 43.5%; P = 0.001) distinguished patients with multiple-positive from those with single-positive cultures. Multivariate logistic regression showed that multi-positivity independently predicted 28-day mortality (adjusted odds ratio, 2.34; 95% confidence interval (CI), 1.03-5.28; P = 0.04) and the Cox regression confirmed that multi-positivity (adjusted hazard ratio, 1.80; 95% CI, 1.13-2.85; P = 0.01) predicted rapid mortality. Patients with multiple versus single positive blood cultures yielding XDRAB had greater morbidity and mortality. Investigators and clinicians should be aware that the blood culture positivity rate impacts outcomes of XDRAB bacteremia.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacteremia; Blood Culture; Carbapenems; Colistin; Critical Illness; Drug Resistance, Multiple, Bacterial; Female; Humans; Intensive Care Units; Leukopenia; Microbial Sensitivity Tests; Middle Aged; Prospective Studies; Severity of Illness Index; Survival Analysis; Thrombocytopenia

Topics: Anti-Bacterial Agents; Child, Preschool; Colistin; Female; Humans; Platelet Count; Thrombocytopenia

To elucidate the effects of antibiotics on platelet adherence phenomena, we examined dissociation of platelet adherence in EDTA-dependent pseudothrombocytopenia by adding Kanamycin or Colimycin. We found the rapid dissociation of platelet adherence caused by addition of Kanamycin (20 mg) or Colimycin (20 mg) in 1 ml of EDTA-anticoagulated blood from patients with EDTA-dependent pseudothrombocytopenia. This dissociation was most remarkable in the sample treated within 30 minutes after venipuncture. When the dissociation occurred, no adherent platelet was found on microscopical examinations. Complete blood cell counts and their histogram patterns after dissociation were almost same as those just after venipuncture. The dissociation occurred as soon as the antibiotics were added and remained fairly long time. The dissociation decreased in proportion to the periods of time between venipuncture and addition of antibiotics. The dissociation was caused by many other antibiotics. However, severer damage were found morphologically by adding most of them in both histogram patterns and microscopical examinations than those of aminoglycoside or peptide antibiotics.

Topics: Adolescent; Adult; Aged; Anti-Bacterial Agents; Colistin; Female; Humans; In Vitro Techniques; Kanamycin; Male; Middle Aged; Platelet Adhesiveness; Thrombocytopenia

Three antimicrobial agents were evaluated as to their ability to neutralize the toxic effects of endotoxin in rabbits. These consisted of two cyclic polypeptides, polymyxin B sulfate and colymycin M (sodium colistimethate), and an aminoglycoside, gentamicin sulfate. Polymyxin B regularly prevented endotoxin-induced leukopenia, thrombocytopenia, and disseminated intravascular coagulation. Colymycin M had similar activity but was not as effective as polymyxin B. Gentamicin demonstrated no neutralizing ability in this study.

Topics: Animals; Colistin; Disseminated Intravascular Coagulation; Endotoxins; Escherichia coli; Gentamicins; Kidney Cortex Necrosis; Leukopenia; Polymyxins; Rabbits; Shwartzman Phenomenon; Thrombocytopenia