Enterobacter Bacteremia: Clinical Features and Emergence of Antibiotic Resistance during Therapy

Abstract

Objectives: To study the effect of previously administered antibiotics on the antibiotic susceptibility profile of Enterobacter, the factors affecting mortality, and the emergence of antibiotic resistance during therapy for Enterobacter bacteremia.

Design: Prospective, observational study of consecutive patients with Enterobacter bacteremia.

Setting: Three university tertiary care centers, one major university-affiliated hospital, and two university-affiliated Veterans Affairs medical centers.

Patients: A total of 129 adult patients were studied.

Measurements: The two main end points were emergence of resistance during antibiotic therapy and death.

Main Results: Previous administration of third-generation cephalosporins was more likely to be associated with multiresistant Enterobacter isolates in an initial, positive blood culture (22 of 32, 69%) than was administration of antibiotics that did not include a third-generation cephalosporin (14 of 71, 20%; P < 0.001). Isolation of multiresistant Enterobacter sp. in the initial blood culture was associated with a higher mortality rate (12 of 37, 32%) than was isolation of a more sensitive Enterobacter sp. (14 of 92, 15%; P = 0.03). Emergence of resistance to third-generation cephalosporin therapy (6 of 31, 19%) occurred more often than did emergence of resistance to aminoglycoside (1 of 89, 0.01%; P = 0.001) or other beta-lactam (0 of 50; P = 0.002) therapy.

Conclusions: More judicious use of third-generation cephalosporins may decrease the incidence of nosocomial multiresistant Enterobacter spp., which in turn may result in a lower mortality for Enterobacter bacteremia. When Enterobacter organisms are isolated from blood, it may be prudent to avoid third-generation cephalosporin therapy regardless of in-vitro susceptibility.

Article and Author Information

  • From the University of Pittsburgh and the Pittsburgh Department of Veterans Affairs Medical Center, Pittsburgh, Pennsylvania; Massachusetts General Hospital, Boston, Massachusetts; Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio; Michael Reese Hospital, Chicago, Illinois; and the University of Florida, Gainesville, Florida. For current author addresses, see end of text.

  • Grant Support: Dr. Chow was partly supported by NIH training grant 5T32AI07333.

  • Requests for Reprints: Victor L. Yu, MD, University of Pittsburgh School of Medicine, 968 Scaife, Pittsburgh, PA 15261.

    Current Author Addresses: Dr. Chow: Division of Infectious Diseases, Harper Hospital, 3990 John R Street, Detroit, MI 48201.

    Dr. Fine: Department of Internal Medicine, University of Pittsburgh School of Medicine, 167 Lothrop Hall, Pittsburgh, PA 15261.

    Dr. Shlaes: Infectious Diseases Section, Veterans Affairs Medical Center, 10701 East Boulevard, Cleveland, OH 44106.

    Dr. Quinn and Ms. Miyashiro: Division of Infectious Diseases, Michael Reese Hospital, Lake Shore Drive at 31st Street, Chicago, IL 60616.

    Dr. Hooper: Massachusetts General Hospital, Infectious Disease Unit, Department of Medicine, Fruit Street, Boston, MA 02114.

    Dr. Johnson: Division of Disease Control, Johns Hopkins School of Hygiene and Health, 615 North Wolfe Street, Baltimore, MD 21205.

    Dr. Ramphal: Division of Infectious Diseases, Box J-277, JHMHC, University of Florida, Gainesville, FL 32610.

    Ms. Wagener and Dr. Yu: Infectious Disease Section, Veterans Affairs Medical Center, University Drive C, Pittsburgh, PA 15240.

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