JOURNAL OF CLINICAL MICROBIOLOGY, Dec. 1990, p. 2848-2849 Vol. 28, No. 12 0095-1137/90/122848-02$02.00/0 Copyright © 1990, American Society for Microbiology Mediastinitis following Open-Heart Surgery: a Case Report JUAN SIERRA-MADERO,"2 KATHLEEN PRATT,2 GERALDINE S. HALL,2 ROBERT W. STEWART,3 JOHN J. SCERBO,4 AND DAVID L. LONGWORTH1* Departments ofInfectious Disease,l Microbiology,2 and Cardiothoracic Surgery3 and Division of Medicine,4 The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44195 Received 4 June 1990/Accepted 16 September 1990 Reports of serious infections caused by Kluyvera spp. have been rare. A case ofKluyvera sp. mediastinitis and bacteremia in a man after open-heart surgery is described. The clinical significance ofKluyvera sp. isolates was debated in early descriptions of the organism. More recent reports, as well as the present case, suggest that the pathogenic potential of this organism is being increasingly recognized by clinicians and microbiologists.

The genus Kluyvera is a recently defined group of organ- lytab, Inc.). Identification to the level was attempted isms in the family which was previously in our laboratory and at the Centers for Disease Control, identified as Enteric Group 8 (5). Kluyvera spp. have been Atlanta, Ga. (J. J. Farmer). The organism was ascorbate considered infrequent opportunistic pathogens. The most positive and grew in cefsulodin-Irgasan-novobiocin medium. common source of human isolates has been the respiratory Fermentation of glucose at 5°C occurred in 17 days. These tract, but Kluyvera spp. have been isolated from blood, results are not conclusive for either or stool, urine, nasopharynx, and bile specimens, wounds, and K. cryocrescens, and the organism may represent a new intravascular devices (2-9; A. Aevaliotis, A. M. Belle, J. P. species of the genus Kluyvera (Table 1). In addition, the Chanione, et al., Clin. Microbiol. Newsl. 7:51, 1985). In organism was positive for catalase; methyl red; growth in most instances, the pathogenic significance of these organ- KCN; ornithine decarboxylase; lysine decarboxylase; utili- isms has been uncertain (5). Scattered reports describing zation of malonate, tartrate, and mucate; esculin hydrolysis; serious systemic infections with Kluyvera spp. have ap- and nitrate reduction. It was motile at 35°C. Fermentation peared. These infections have involved the urinary tract (8), test results were positive for glucose (with gas production), the gallbladder (7), and the gastrointestinal tract (3). Cathe- lactose, mannitol, salicin, sorbitol, arabinose, raffinose, ter-related bacteremia has also been described (9). We report rhamnose, maltose, xylose, trehalose, cellobiose, melibiose, a patient with Kluyvera sp. mediastinitis and bacteremia and mannose and negative for adonitol, glycerol, dulcitol, following open-heart surgery. inositol, and erythritol. The isolate did not liquefy gelatin A 74-year-old man was admitted to The Cleveland Clinic and was negative for the production of indole, oxidase, Foundation on 2 July 1989 with unstable angina. His medical hydrogen sulfide, urease, arginine dihydrolase, phenylala- history was remarkable for insulin-requiring adult onset nine deaminase, and DNase (25°C) and for sodium acetate diabetes mellitus, hypertension, gout, and end-stage renal utilization. disease requiring chronic hemodialysis. Cardiac catheteriza- Susceptibility testing by means of broth microdilution tion disclosed triple-vessel coronary atherosclerosis, moder- (trays prepared in-house) revealed susceptibility to gentami- ate left ventricular dysfunction, and moderately severe aor- cin, tobramycin, ceftizoxime, ceftazidime, ciprofloxacin, tic stenosis. Only 7 July 1989, the patient underwent a and imipenem. The organism was resistant to ampicillin, five-vessel saphenous vein coronary artery bypass and aortic cefamandole, cephalothin, ticarcillin-clavulanic acid, piper- valve debridement. Postoperatively he developed acute aor- acillin, and aztreonam. tic insufficiency which required aortic valve replacement on Ceftizoxime was added to the regimen, and vancomycin 8 July 1989. This was complicated by postoperative bleeding was discontinued. The patient remained afebrile, but puru- which necessitated mediastinal exploration later that day. lent drainage from the wound persisted. On 24 July 1989, the Thereafter the patient was maintained on cefamandole for 10 patient underwent extensive sternal and mediastinal debride- days after surgery. On 21 July 1989, drainage from the ment with placement of mediastinal irrigation tubes. Irriga- sternal wound was noted. The patient was afebrile, and his tion with povidone-iodine (Betadine) was begun. Intraoper- leukocyte count was 16,000/mm3. Superficial sternal debride- ative cultures of purulent material within the mediastinum ment was performed, and vancomycin and gentamicin were again yielded a Kluyvera sp. The isolate remained suscepti- administered. Gram stain of the wound drainage disclosed ble to ceftizoxime and gentamicin, and these antibiotics were gram-negative bacilli, and cultures of the wound and expec- continued. The patient remained afebrile and completed a torated sputum grew a Kluyvera sp. within 24 h. Two 3-week course of ceftizoxime and gentamicin. Mediastinal separate blood cultures, one drawn through a central venous irrigation with povidone-iodine was continued. After antibi- pressure line and the other through an arterial line, yielded a otics were discontinued, however, cultured specimens of Kluyvera sp. In both instances, the organism grew in the mediastinal drainage and a pleural effusion grew Candida Isolator tube (Dupont, Wilmington, Del.) and a tryptic soy albicans. An associated pneumonia was not identified, and broth bottle within 24 h of collection. the patient was believed to have fungal mediastinitis. He The organism was identified as a Kluyvera sp. by Vitek received 500 mg of amphotericin B over the subsequent 2 AMS (Vitek Systems, Hazelwood, Mo.) and by API (Ana- weeks. Although his infection responded to therapy, his course was complicated by recurrent upper gastrointestinal bleeding which required laparotomy with gastrectomy and * Corresponding author. vagotomy. Despite these procedures, bleeding recurred and 2848 VOL. 28, 1990 NOTES 2849

TABLE 1. Differentiation within the genus Kluyvera" probably represented colonization rather than infection. Only five isolates in that series were from blood, but clinical Result of: information on those cases was not provided (5). On the Species Ascorbate D-Glucose Growth Cephalothin and basis of those five isolates, plus another isolate (from gall- testtest fermentation5°C (21 days)at onagarbCIN zonecarbenicillinsize (mm) bladder drainage fluid) considered significant by Braunstein and coworkers (2), Farmer et al. suggested that Kluyvera K. ascorbata + - + <17 spp. are "infrequent opportunistic pathogens" (5). Since K. cryocrescens - + - >17 then, only six reports have appeared in the literature docu- Present isolate + + + NDC menting Kluyvera spp. as pathogenic organisms in humans. a Data for K. ascorbata and K. crysocrescens are from reference 1. Wong described a case of nosocomial K. cryocrescens b Cefsulodin-Irgasan-novobiocin agar (J. J. Farmer, personal communica- bacteremia in a 17-month-old child in whom the source tion.) appeared to be a Broviac catheter (9). Luttrell and cowork- C ND, Not done. ers recently described a soft tissue infection with a Kluyvera sp. in a previously healthy woman (6). Tristram and Forbes was refractory to celiac artery embolization. The patient reported a case of bacteremia and urinary tract infection (8), died on 6 September 1989, secondary to intractable gastro- and Thaller et al. isolated K. cryocrescens from the gallblad- intestinal bleeding. Postmortem examination was performed der of a woman with acute cholecystitis (7). In addition, and disclosed no evidence of residual mediastinitis. reports by Fainstein et al. (3) and Aevaliotis et al. (Clin. In 1956, Asai and Okumura proposed the genus Kluyvera Microbiol. Newsl., 1985) have associated Kluyvera spp. with for a group of gram-negative with polar flagella diarrhea in a few patients. which produced large amounts of alpha-ketoglutaric acid Our case represents the first description of mediastinitis during the fermentation of glucose (1). In 1981, Farmer et al. caused by this organism. The isolation of a Kluyvera sp. compiled their experience with more than 100 isolates of a from the trachea suggests that colonization ofthe respiratory gram-negative, oxidase-negative fermentative bacterium tract may have led to subsequent mediastinal infection and that previously had been grouped under the name of Enteric bacteremia. Our patient's relatively indolent clinical course Group 8 and recognized that the biochemical reactions were is consistent with other published reports. Kluyvera spp. are almost identical to those of the organisms defined by Asai infrequently associated with human disease and appear to be and Okumura (5). Farmer and coworkers proposed the mainly commensal organisms which rarely produce oppor- reclassification of the organism as a new genus within the tunistic infections. An increased awareness of these organ- family Enterobacteriaceae because of its unique biochemical isms by clinical microbiology laboratories will likely lead to characteristics. a better understanding of the epidemiology and clinical The genus Kluyvera is composed of three species: K. presentation of Kluyvera infections. ascorbata, the type species of the genus and the one most frequently isolated in clinical specimens (5); K. cryo- crescens, an environmental isolate found in food, soil, and LITERATURE CITED sewage but rarely present in clinical specimens (5); and 1. Asai, T. S., and T. Okumura. 1956. On a new genus Kluyvera. Kluyvera sp. group 3, an infrequently isolated strain from Proc. Jpn. Acad. 32:488-493. any source, which appears to be distinct from the other two 2. Braunstein, H., M. Tomasulo, S. Scott, and M. P. Chadwick. species as determined by DNA hybridization studies. Mem- 1980. A biotype of Enterobacteriaceae intermediate between bers of the genus Kluyvera are closely related to other Citrobacter and Enterobacter. Am. J. Clin. Pathol. 73:114-116. members of the such as Enterobacter 3. Fainstein, V., R. L. Hopfer, K. Mils, and G. P. Bodey. 1982. Enterobacteriaceae, Colonization by or diarrhea due to Kluyvera species. J. Infect. spp. and Citrobacter spp. Kluyvera spp. differ, however, in Dis. 145:127. their ability to utilize malonate and to ferment raffinose. 4. Farmer, J. J., III, B. R. Davis, F. W. Hickman-Brenner, A. Automated systems such as the Vitek AMS (Vitek Systems) McWhorter, G. P. Huntley-Carter, M. A. Asbury, C. Riddle, and biochemical kit systems such as API (Analytab, Inc.) H. G. Wathen-Grody, C. Elias, G. R. Fanning, A. G. Steigerwolt, can identify the organisms to the genus level, but further C. M. O'Hara, G. K. Morris, P. B. Snmith, and D. J. Brenner. testing is needed to differentiate the species. 1985. Biochemical identification of new species and biogroups of Table 1 summarizes the biochemical characteristics that Enterobacteriaceae isolated from clinical specimens. J. Clin. can be used to differentiate K. cryocrescens from K. ascor- Microbiol. 21:46-76. bata and describes the results of these tests for the 5. Farmer, J. J., III, G. R. Fanning, G. P. Huntley-Carter, B. present Holmes, F. W. Hickman, C. Richard, and D. J. Brenner. 1981. isolate. Results of the ascorbate test and glucose fermenta- Kluyvera, a new (redefined) genus in the family Enterobac- tion at 5°C have been described by Farmer et al. (5). teriaceae: identification of Kluyvera ascorbata sp. nov. and Measurement of zones of inhibition around cephalothin and sp. nov. in clinical specimens. J. Clin. carbenicillin disks remains a simple approach to the differ- Microbiol. 13:919-933. entiation in most clinical laboratories. Isolates of the genus 6. Luttrell, R. E., G. A. Rannick, J. L. Soto-Hernandez, and A. Kluyvera have been susceptible in vitro to aminoglycosides, Verghese. 1988. Kluyvera species soft tissue infection: case broad-spectrum cephalosporins, imipenem, and aztreonam report and review. J. Clin. Microbiol. 26:2650-2651. and resistant to narrow- and extended-spectrum cephalospo- 7. Thaller, R., F. Berlutti, and M. C. Thaller. 1988. A Kluyvera cryocrescens strain from a gallbladder infection. Eur. J. Epide- rins and extended-spectrum penicillins (5). Our isolate miol. 4:124-126. showed a similar susceptibility pattern, except for resistance 8. Tristram, D. A., and B. A. Forbes. 1988. Kluyvera: a case report to aztreonam. of urinary tract infection and sepsis. Pediatr. Infect. Dis. J. In the initial reports, the pathogenic significance of 7:297-298. Kluyvera spp. was unclear (1, 5). Most of the isolates in the 9. Wong, V. K. 1987. Broviac catheter infection with Kluyvera series of Farmer et al. were from respiratory specimens and cryocrescens: a case report. J. Clin. Microbiol. 25:1115-1116.