Infections caused by Acinetobacter baumannii susceptible only to polymyxin in a gynecologic oncology unit

Abstract

Large multicenter surveillance studies of hospital infections show an increasing incidence of Acinetobacter baumannii infections worldwide [1]. Colonization and infection by multidrug-resistant (MDR) microbes are increasingly common in hospitalized patients. Among such isolates, A. baumannii is a common microorganism, and is usually resistant to antimicrobials such as beta-lactams and carbapenems [2,3,4].Three cases of A. baumannii postoperative wound infections that occurred in patients who underwent operations for gynecologic cancer are presented. Microbe identification was performed using the autoSCAN system (Databaring) or API system; the Kirby-Bauer method plus E-test for colistin resistance were used for antimicrobial susceptibility testing.A 65-year-old patient with endometrial carcinoma presented with vaginal bleeding due to disease recurrence. The patient had initially been treated with radiotherapy because of significant comorbidity: pulmonary hypertension, relatively low ejection fraction of 50%, diabetes mellitus, and body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) of 31.2. She underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. The patient's comorbidity necessitated a 48-hour stay in the intensive care unit. She received surgical prophylaxis with 3 g of piperacillin and 0.75 g of tazobactam twice daily and 500 mg of metronidazole 3 times daily for 3 days.On the 10th postoperative day, the surgical incision was found to be red and edematous with subcutaneous serosanguinous fluid. Fluid culture revealed A. baumannii susceptible only to colistin. She received intravenous colistin (3 million IU 3 times daily) and surgical wound cleansing twice daily. Twenty-two days later the antibiotic was discontinued because of anaphylactoid reaction. Three months later the patients was receiving chemotherapy for her primary disease and the wound was improving in a slow healing process.A 60-year-old patient with stage Ib cervical carcinoma underwent a Wertheim-Meigs procedure.

Minocycline attenuates colistin-induced neurotoxicity via suppression of apoptosis, mitochondrial dysfunction and oxidative stress

“…The two clinically used polymyxins, polymyxin B and colistin (Figure 1), are lipopeptide antibiotics that are used as last-line therapy against problematic Gram-negative pathogens. [1][2][3][4][5][6] Available population pharmacokinetic and pharmacodynamic data from our group indicated that the currently recommended dosage regimens of polymyxins achieve suboptimal plasma concentrations; and that higher dosing is needed to achieve effective killing and prevent resistance. 7 Neurotoxicity is an unwanted side effect that limits effective polymyxin therapy.…”