Successful treatment of carbapenemase producing Enterobacteriaceae peritonitis: 'Old therapy for a new bug'.

Multidrug-resistant organisms cause significant morbidity and mortality. Infections due to resistant gram-negative bacilli are increasingly being reported. For years, carbapenem antibiotics have been successfully used to treat infections due to resistant Enterobacteriaceae, such as Escherichia coli and Klebsiella pneumoniae, including those producing extended spectrum ß-lactamases, a subset of ß-lactamase enzymes that confer broad resistance to penicillins and cephalosporins. More recently, carbapenem-resistant Enterobacteriaceae have emerged as pathogenic organisms, which confer broad resistance to most ß-lactam antibiotics including 'last-line' carbapenems. However, different types of carbapenemases confer diverse spectra of antibiotic resistance. Here, we describe the case of an 84-year-old lady on peritoneal dialysis (PD) for 3 years who, on developing carbapenem-resistant Klebsiella pneumoniae PD peritonitis, was successfully treated with colistin, an antimicrobial agent first used in the 1950s.

Evaluation of the BD Phoenix automated microbiology system for identification and antimicrobial susceptibility testing of Enterobacteriaceae.

We evaluated the accuracy of the BD Phoenix system for the identification (ID) and antimicrobial susceptibility testing (AST) of 251 isolates of the family Enterobacteriaceae representing 31 species. Organisms were inoculated onto the Phoenix panel according to the manufacturer's instructions. The results from conventional biochemical tests were used for the reference method for ID. Agar dilution, performed according to the CLSI guidelines, was the reference AST method. Essential and categorical agreements were determined. The overall levels of agreement for the genus- and species-level identifications were 95.6% and 94.4%, respectively. Fourteen isolates were incorrectly identified by the Phoenix system; 10 of these were incorrectly identified to the species level. Three of these were Enterobacter (Pantoea) species and four of these were Shigella spp. misidentified as Escherichia coli. For AST results, the essential and categorical agreements were 98.7% and 97.9%, respectively. The very major error, major error, and minor error rates were 0.38%, 0.33%, and 1.8%, respectively. Six isolates (three E. coli isolates and three Klebsiella isolates) were extended-spectrum beta-lactamase producers. All six were flagged by the Phoenix system expert rules. The Phoenix system compares favorably to traditional methods for ID and AST of Enterobacteriaceae.

Utility of extended blood culture incubation for isolation of Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella organisms: a retrospective multicenter evaluation.

The incidence of and average time to detection for Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella (HACEK) bacteria in blood cultures with standard incubation and the utility of extended incubation of blood culture bottles were reviewed at four tertiary care microbiology laboratories. HACEK organisms were isolated from 35 (<0.005%) of 59,203 positive blood cultures. None of 407 blood cultures with extended incubation grew HACEK or other bacteria. Bacteremia from HACEK bacteria is rare, and extended incubation of blood cultures to recover HACEK bacteria is unnecessary.

Leptotrichia buccalis bacteremia in two patients with acute myelogenous leukemia.

Leptotrichia buccalis is rarely implicated in systemic disease. We report two patients with clinically significant L. buccalis bacteremia which developed during the neutropenia secondary to chemotherapy. Based upon our experience, L. buccalis bacteremia should be considered in certain high-risk immunocompromised patients with mucositis and/or gingivitis.