Nancy Khardori

Nosocomial infection caused by Xanthomonas maltophilia: a case-control study of predisposing factors.

Factors predisposing to clinically significant nosocomial infection with Xanthomonas maltophilia were examined in a matched case-control study using multivariate techniques. Sixteen cases occurred among cancer patients in a six-month period, including an apparent cluster of three cases in an intensive care unit. These infections were unusually serious; eight patients had disseminated infection caused by X maltophilia and six died as a result of their infections. Among the 64 factors that were examined, therapy with broad-spectrum antibiotics and central venous catheterization were found to significantly increase susceptibility to infection. Therapy with imipenem was more than ten times more frequent among cases than among controls (p less than .001). All fatal infections occurred in patients who had received imipenem, including two patients who died before the organism could be identified and appropriate therapy instituted. Infection with X maltophilia should be suspected in patients who develop superinfection while receiving imipenem, and prompt therapy should be instituted to improve chances of survival. Because a common environmental source of X maltophilia was not identified, further study is necessary to determine specific preventive measures.

β‐Lactam regimens for the febrile neutropenic patient

A total of 535 evaluable febrile episodes in neutropenic patients were randomly assigned to treatment with ticarcillin‐clavulanate plus vancomycin (TV), ceftazidime plus vancomycin (CV), or all three antibiotics (TCV). The TCV regimen was significantly more effective than TV, considering all evaluable episodes, documented infections, gram‐negative infections, and infections in patients with persistent severe neutropenia (< 100 neutrophils/mm3). The results with CV were intermediate between TV and TCV. The toxicities were similar with all three regimens and consisted primarily of skin rashes. The TCV regimen is effective for empiric therapy of fever in neutropenic patients and probably should be utilized in preference to CV or TV, although its superiority over CV in this study was inconclusive.

In vitro susceptibility of Xanthomonas (Pseudomonas) maltophilia to newer antimicrobial agents

The susceptibilities of 45 clinical and 3 environmental isolates of Xanthomonas maltophilia to 14 antimicrobial agents was determined by broth microdilution. The newer quinolones PD117596, PD117558, PD127391, A-56620, amifloxacin, and fleroxacin were the most active agents tested, with 70 to 99% of isolates being susceptible to these agents. All isolates were resistant to trospectomycin. The new aminoglycosides SCH24120 and SCH22591 were active against 12 and 1% of isolates, respectively.

Spectrum and outcome of microbiologically documented listeria monocytogenes infections in cancer patients.

At the M.D. Anderson Cancer Center (Houston), Listeria monocytogenes was cultured from 14 patients between 1980 and 1987. The case records of 11 of these patients were reviewed. Underlying malignancies included acute leukemia (three), lymphoma (two), myeloma (one), adenocarcinoma of colon (two), carcinoma of breast (one), carcinoma of lung (one), and Kaposis sarcoma associated with the acquired immune deficiency syndrome (one). Listeria monocytogenes was cultured from blood (eight patients), cerebrospinal fluid (CSF) (two patients), and from both blood and CSF in one patient. All patients were receiving immunosuppressive therapy including corticosteroids in seven. An absolute neutrophil count of less than 1000/mm3 was noted in five. Bacteremia was the predominant type of infection and ten patients responded to antimicrobial therapy.

SINGLE AGENT THERAPY FOR INFECTIONS IN CANCER PATIENTS : A PROSPECTIVE RANDOMIZED TRIAL COMPARING THREE EXTENDED-SPECTRUM CEPHALOSPORINS

Three hundred and twenty patients were enrolled in a prospective randomized trial comparing cefoperazone, ceftizoxime and ceftriaxone for initial therapy of infectious episodes in cancer patients. Patients with neutropenia were excluded. In 286 evaluable episodes, the response rates associated with the three agents were 77 % for cefoperazone, 70 % for ceftizoxime and 72 % for ceftriaxone, with no statistically significant differences between the three treatment groups. The overall response rate for all episodes of pneumonia (64 %) was significantly lower than the response rate for all other infections (81 %; p=0.002), and the mortality associated with pneumonia (9 %) was higher than that associated with all other episodes (2 %; p=0.01). Patients with infections due to gram-negative organisms responded well to all three agents, whereas patients with gram-positive infections responded more favorably to cefoperazone. Two different schedules of ceftriaxone were used. The clinical response did not differ significantly between patients receiving ceftriaxone once daily and those receiving it twice daily. The incidence of superinfection and relapse was extremely low and all three agents were well tolerated. It is concluded that extended spectrum cephalosporins are effective as single agents for the treatment of infections in cancer patients with adequate neutrophil counts.