the detection of mcthicillin resistant staphylococci among clinical isolates. Prog. & Abstr. 24th Intcrsci. Conf. on Antimicrob. Agents Chemother. No. 4, p. 90.

5. l taley, R. W. et al. 1982. The emer- gence of methicillin-resistant Staphylo- coccus attreus infections in the United States hospitals. Ann. Intern. Med. 97:297-308.

6. Jarvis, W. R. et al. 1984. Noso- comial infection surveillance, 1983, pp. 955-2155. In MMWR CDC sur- veillance summaries, Vol. 33. Centers for Disease Control, Atlantic, GA.

7. Karchmer, A. W., G. A. Archer, and W. E. Dismukes. 1983. Stapl,y- lococcus epidermidis causing prosthetic valve endocarditis: microbiologic and clinical observations as guides to therapy. Ann. Intern. Med. 98:447- 455.

8. Lowy, F. D. et al . 1983. Reliability of in vitro susccptibility tests for de- tecting coagulase-negativc staphylo- coccal resistance to penicillinase-rcsis- tant semisynthetic penicillins. J. Clin. Microbiol. 18:1122-1126.

9. MeDougal, L. K., and C. Thorns- berry. 1984. New recommendations for disk diffusion antimicrobial suscep- tibility tests for methicillin-resistant (heteroresistant) staphylococci. J. Clin. Microbiol. 19:482 488.

10. National Committee for Clinical Laboratory Standards. 1983. Methods for dilution antimierobial sus- ceptibility tests for bacteria that grow aerobically, M7-T. Tentative standard. National Committee for Clinical Labo- ratory Standards, Villanova, PA.

11. National Committee for Clinical Laboratory Standard. 1984. Perfor- mance standards for antimicrobial disk

susceptibilit3;' tests. 3d Ed. M2-A3. Approved standard. National Com- mittee for Clinical Laboratory Stan- dards, Villanova, PA.

12. Schoenknecht, F. D., L. D. Sabath, and C. Thornsberry. 1985. Suscepti- bility tests: special tests, p. 1000- 1008. hz E. H. Lcnnette, A. Balows, W. J. Hausler, Jr., and H. J. Shadomy (ed.), Manual of clinical microbiology, 4th Ed. American Society for Microbi- ology, Washington, D.C.

13. Sutherland, R., and G. N. Rolinson. 1964. Characteristics of methicillin-re- sistant staphylococci. J. Bacteriol. 87:887-899.

14. Thornsberry, C., and L. K. Mc- Dougal. 1983. Successful use of broth microdilution in susceptibility tests for methieillin-resistant (heteroresistant) staphylococci. J. Clin. Microbiol. 18:1084-1091.

Case Report m e

Yersinia pseudotuberculosis as a Cause of Blood Colitis

Gwen Stevens, M.S. Department of Pathology and Laboratory

Medicine Mt. Zion Hospital and Medical Center San Francisco, California 94120

A 35-y-old homosexual male pre- sented in the emergency room with se- vere bloody diarrhea and a 4-day his- tory of lower abdominal pain. He de- nied any nausea, vomiting, chills, or fever. There was no history of recent travel or contact with sick animals and the patient had been well except for Hepatitis B which had been diagnosed 6 months previously. Physical exami- nation was unremarkable and anoscopy was within normal limits. His sole partner had been in good health.

A single stool specimen was ob- tained and sent to the laboratory. The Gram stain showed 4 + WBCs. Ex- amination of the specimen for parasites was negative as was culture for Sahno- nella, Shigella, and Campylobacter. Yersinia pseudotuberculosis was recov-

ered from routine enteric media after 2 days ' incubation. On XLD and MacConkey plates the colonies were small, raised, and colorless. Single colony isolates were inoculated to triple sugar iron (TSI), lysine iron (LIA), and urea agar slants. After overnight incubation at 35°C, the TSI showed an alkaline slant over a slightly acid butt; the LIA reaction was an acid slant over an alkaline butt and the urea was negative. Extended incu- bation of these media produced the reactions listed in Table I. Because this pattern suggested a slow growing fermenter, Yersinia spp. was sus- pected. A test for motility at room temperature and biochemical tests in- cubated at both room temperature and 35°C were performed. The isolate was identified as Y. psettdotttberctdosis by API 20E (code numbers 0014100, 0004110, and 0014112) and MicrolD (code number 20161). Reactions pro- duced at room temperature did not differ from those at 35°C and the or- ganism was not motile at room tem- perature. The identity of the isolate was confirmed by the San Francisco Public Health Microbiology Laboratory using conventional biochemical tests.

A summary of the isolate 's biochem- ical reactions is shown in Table 2.

Antimicrobial susceptibili ty studies were performed by the standard disk diffusion method (3). The organism was susceptible to ampicill in, carbeni- cillin, t icarcillin, mezlocill in, cephalo- thin, cefamandole, cefoxitin, cefo- taxime, gentamicin, tobramycin, tetracycline, and trimethoprim-sulfa- methoxazole (TP/SX). The pat ient 's symptoms resolved after treatment with TP/SX and he remains in good health.

Although Yershlia enterocolitica is well recognized a cause of acute infec- tious enteritis (2, 7, 8), Y. pseudotu- berculosis is more commonly associ- ated with mesenteric lymphadenit is

Tab le 1 S u m m a r y of Sc reen ing Biochemicals"

24 hr 48 hr 72 hr

TSI K/a K/A K/A L1A a/N A/A K/A Urea Neg Neg Neg

" K = alkaline slant or alkaline butt; a = slightly acid; A = acid slant or acid butt; N = no change.

Clinical Microbiology Newsletter 7:20.1985 © 1985 Elsevier Science Publishing Co., Inc. 0196-4399/85/S0.00 + 02.20 149

i

T a b l e 2

C o m p a r i s o n o f M t . Z i o n Hosp i t a l ( M Z H ) I so la te to R e c o g n i z e d Species"

Reagent/Test

Yersinia MZH isolate MZH MZtt pseudo- (conventional isolate isolate tuberculosis

biochemicats) b API 20E MicrolD (% + )b

Oxidase - - Catalase 4- ONPG - - Indole - - Nitrate red + + Citrate, simmons - - H2S - (TSI) - Motility 35°C Motility 22°C Urease - + / - Lysine decarb. - - Ornithine decarb. - - Arginine dihyd. - - Phenylalanine

deaminase Acid from:

Glucose 4- + Xylose + Mannitol 4- + Lactose Sucrose - - Maltose ( + ) Adonitol Arabinose ( + ) + / - Dulcitol Glycerol ( + ) Inositol - - Thamnose + + / - Salicin ( + ) Sorbitol - - Raffinose Trehalose ( + ) Melibiose ( + ) -

Gas from glucose Methyl red + Voges-Proskauer - - Gelatin - - Esculin ( + )

4-

4-

4-

R

4-

D

+

0 100 70 0

95 0 0(TSI) 0

+

95% 0 0 0

100 100 100

0 0

95 0

50 0

50 0

70 25

0 15

100 80

0 I00

0 0

95

" +: positive within 24 hr; (+): positive at 48-72 hr; - : negative at 72 hr. b ConventionaI biochemical tests performed at San Francisco Public ttealth Microbiology Laboratory.

(pseudoappendici t i s ) , sept icemia, and

occas ional ly terminal ileitis (1, 2, 4 -

6). Its role as a cause o f colitis is not

wel l documented , perhaps because

Yershffa spp. are not rout inely sought

in stool cul tures , and even when

present, may be ove rg rown by more

rapidly g rowing fecal flora. Our iso-

late was present in h 1 - 2 + quant i ty

accompanied by a few colonies o f lac-

tose fermenters .

This isolate produced atypical reac-

tions in TSI and LIA screening media ,

probably due to its s low growth rate.

Laborator ies should be alert for any

lac tose-negat ive enteric isolate that

produces TSI and LIA reactions con-

sistent with those o f a s low-growing

fermenter . In addit ion, posi t ive urease

and r o o m temperature moti l i ty tests are

unrel iable aids in the presumpt ive

identif ication o f this organism.

References 1. Capron, J . R. et al. 1981. Liver ab-

scess complicating Yersh~ia psettdotu- berculosis ileitis. Gastroenterology 8 1 : 1 5 0 - 1 5 2 .

2. Kelly, M. , D. Brenner, and J . J . Fa rmer . 1985. Enterobacteriaceae, pp. 263-267. In E. H. Lennette et al. (eds.), Manual of clinical microbi- ology, 4th Ed. American Society for Microbiology, Washington, D.C,

3. National Commit tee for Clinical Labora tory Standards. Performance standards for antimicrobial disk sus- ceptibility tests, M2A3. 1984. 3d Ed. NCCLS, Villanova, PA.

4. Paff, J . R. , D. Tripplett , and N. S. Thomas. 1976. Clinical and laboratory aspects of Yersinia pseudotuberculosis infections with a report of two cases. Am. J. Clin. Pathol. 16:101-110.

5. Savage, A., and D. Dunlop. 1976. Terminal ileitis due to Yersinia pseu- dotuberculosis. Br. Med. J. 1 :916- 917.

6. Vantrappen, G. et al. 1976. Yersinia enteritis and enterocolitis. Gastroenter- ological aspects. Gastroenterology 72:220-227.

7. Weber , J . , N. B. Finlayson, and J . B. Mark . 1970. Mesenteric lym- phadenitis and terminal ileitis due to Yersinia pseudotuberculosis. N. Engl. J. Med. 283:172-174.

8. Weissfeld, A. S. 1981. Yersinia en- terocotitica. Clin. Microbiol. Newsl. 3 :91-93 .

150 0196-4399/85/$0.00 + 02.20 © 1985 Elsevier Science Publishing Co.. Inc. Clinical Microbiology Newsletter 7:20,1985