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Title : A 59 year-old female w/Fever and diarrhea for 3 weeks
Date : October 16, 2010
Contributed by

Dr. Chi-Sook Moon
Department of Rheumatology & Infectious Diseases
Busan-Paik hospital, College of Medicine, Inje University

Patient History
Age/Sex A 59-year-old female
Chief complaint Fever and diarrhea for 3 weeks
Present illness

A 59 year-old female presented with intermittent fever and diarrhea. Two month earlier, the patient had been diagnosed with tuberculous arthritis on her right knee. Anti-tuberculosis medications, including isoniazid, ethambutol, rifampin and pyrazinamide, had been administered. After 6 weeks, fever, abdominal discomfort and watery diarrhea developed and the patient was admitted to local clinic. Based on the assumption of drug-associated colitis or other infectious colitis, ciprofloxacin and metronidazole were administered as initial empirical antibiotics. After 10 days, fever and abdominal discomfort were aggravated and she was transferred to our hospital.

Past medical history

The patient had been diagnosed with rheumatoid arthritis 12 years before and had taken prescribed medications including hydroxychloroquine, methotrexate, steroids and NSAIDs.

Physical examination

Vital sign: BT 38.6℃, BP 130/80 mmHg, PR 110bpm, RR 25 breaths per minute. On exam, she showed periumbilical tenderness, diffuse abdominal distension and increased bowel sounds. Lab findings revealed a WBC of 22.4 x 109/liter, and a CRP of 7.24 mg/liter. On stool examination, culture for Salmonella and Shigella, Clostridium difficile toxin and parasite were all negative. Blood culture grew gram-positive cocci in 2 sets. Vancomycin was administered empirically. After 10 days, fever and abdominal discomfort persisted and subsequent blood cultures grew same organisms. From google images. http://bacterioweb.univ-fcomte.fr/photo2detail.php?id=227.

Initial laboratory findings

Abdomen CT and Cardiac echocardiography were performed. Trans-esophageal echocardiography showed no evidence of vegetation.

Radiologic findings

Question - ID Case of the Week ( October 16, 2010 )
What would be the causative microorganism?
Correct Answer

The isolate was identified as a Leuconostoc species that was naturally resistant to vancomycin. A 16S rDNA sequence analysis finally identified the isolates as Leuconostoc lactis.


Leuconostoc species naturally reside in dairy products as well as vegetables and have been isolated sporadically from the vagina and from gastric fluid. Leuconostoc could be present in the gastrointestinal flora of those patients with underlying gastrointestinal disease. Under conditions of disrupted mucosal integrity, Leuconostoc may be able to reach the bloodstream from the colonized gastrointestinal tract. Risk factors for Leuconostoc bacteremia include an immunocompromised state, an indwelling central catheter, prior use of vancomycin and gastrointestinal pathology.   Leuconostoc species are resistant to vancomycin because their cell walls fail to provide a target for the antimicrobial agent. There are no established standards for selecting antimicrobial agents to which Leuconostoc is susceptible. Leuconostoc species are generally susceptible to penicillin, ampicillin, clindamycin, macrolides, carbapenems and aminoglycoside. In most cases, Leuconostoc bacteremia can be controlled with penicillin or ampicillin.


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