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Journal of Clinical Microbiology, April 2008, p. 1545-1547, Vol. 46, No. 4
0095-1137/08/$08.00+0 doi:10.1128/JCM.01895-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.
| CASE REPORT |

Shinji Isomine,3,
Haru Kato,2,
Yoshimasa Sasaki,4
Motohide Takahashi,2
Koji Sakaida,3
Yukiko Nagano,2 and
Yoshichika Arakawa2*
Medical Microbiology Laboratory,1 Department of Anesthesiology, Funabashi Municipal Medical Center, Chiba,3 Department of Bacterial Pathogenesis and Infection Control, National Institute of Infectious Diseases,2 Food Safety and Consumer Affairs Bureau, Ministry of Agriculture, Forestry and Fisheries, Tokyo, Japan4
Received 24 September 2007/ Returned for modification 21 January 2008/ Accepted 29 January 2008
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On arrival, he had a Glasgow Coma Scale score of 3, bilateral pupils dilated 6 mm in diameter with no light reflex. His heart rate was 108 beats/min, and blood pressure was undetectable except for palpable slight pulsation of the common carotid artery. Examination of the patient's chest revealed dark red cutaneous ecchymoses measuring approximately 5 by 5 cm in the right anterolateral chest with marked swelling. A computed tomographic (CT) scan was done immediately while the patient was supported with fluid resuscitation. The chest CT scan showed striking subcutaneous emphysema and destruction of muscle tissue centering around the anterior to lateral region of the right chest and rich gaseous contamination in the right subclavian vein and pulmonary artery (Fig. 1A to C).
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FIG. 1. Chest CT scan imaging 20 min after arrival. (A) Right subclavian vein filled with entrapped gas (arrow). (B) Marked subcutaneous emphysema with destruction of muscle tissue around right chest (arrow) and massive gas entrapped in the pulmonary artery (arrowhead). (C) CT scan revealing many bubbles (arrow) below the massive gas entrapment in the pulmonary artery.
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TABLE 1. Patient clinical laboratory data
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FIG. 2. Microbiological and PCR amplification findings for Clostridium chauvoei. (A) Grayish white, rough colonies with beta-hemolysis around bacterial colonies after 48 h of culture on Brucella HK RS agar under anaerobic conditions. (B and C) Gram stain morphology and Wirtz-Conklin spore stain, respectively, from growth on Brucella HK RS agar (magnification, x1,000). Gram-positive rods with subterminal endospores were noted. (D) Five percent polyacrylamide gel electrophoresis of PCR products of the 16S-23S rRNA gene intergenic spacer region. Lane 1, patient's isolate; lane 2, Clostridium chauvoei ATCC 10092; lane 3, Clostridium septicum ATCC 12464; lane 4, negative control; lane M, 100-bp ladder as a molecular marker. A 522-bp amplicon is observed in both lanes 1 and 2.
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C. chauvoei is of veterinary importance as a causative pathogen of blackleg, a highly fatal gas gangrenous infection of cattle and sheep (7). Other susceptible hosts reported so far are limited to animals, including goats and swine (2). No human gas gangrene case caused by this bacterial species has been recognized to date. So it is the rare clinician who notices the presence of C. chauvoei as a possible causative pathogen of human gas gangrene and invasive clostridial infections. C. septicum and C. chauvoei are genetically very similar, making them difficult to distinguish in biochemical testing. In the present study, however, the human fulminant gas gangrene case was confirmed to be caused by C. chauvoei after precise genetic characterizations including analyses of the 16S rRNA gene (6) and the 16S-23S rRNA gene intergenic spacer region (9, 10). Therefore, strains from human patients with devastating clostridial infections that have been identified as C. septicum are worth checking out by further genetic identification, as was done in the present study.
In the present case, we initially suspected that cardiac arrest might have been caused by cardiac tamponade, massive bleeding of the chest wall, and/or hemopneumothorax triggered by trauma, which was not evident by CT examination. Although subcutaneous emphysema was noted and the immediate cause of sudden cardiac arrest was thought to be pulmonary air embolism, it was still difficult to consider that the minor trauma observed in the contusion area led to cardiac arrest. Moreover, clinical findings of high fever before and after trauma accompanied by suspected respiratory infection, an abnormal CRP level, and severe mixed acidosis prompted us to perform a microbiological examination of the needle aspirate specimen from the subcutaneous emphysematous lesions. Finally, the diagnosis of gas gangrene was exactly confirmed by isolation and identification of C. chauvoei from the specimen.
C. chauvoei is a common microbe both in soil and in the guts of ruminants. Blackleg usually appears to be a nontraumatic endogenous infection in cattle harboring the organism in their gastrointestinal tracts (2), probably due to ingestion of spores. The spores or trophozoites may translocate from the intestine into humoral circulation and lie dormant in muscle and other tissues until some ectogenic causes induce bacterial proliferation. In sheep, the disease is frequently associated with wounding caused by shearing, castrating, or tail docking (3). Since gas gangrene occurred at the site of blunt trauma in our case, it was likely the result of wound contamination. However, there was no apparent open wound at the contusion area, so the possibility of a nontraumatic or intrinsic infection could not be excluded. It is also not known whether C. chauvoei resides in the intestinal tracts of humans as transitory microbial flora. The patient had suffered from mild diabetes mellitus prior to the onset of gas gangrene, but no obvious colon cancer, a possible means of entrance of microbes, was found on the basis of the abdominal CT scan. It was also unclear whether the high fever and symptoms of upper respiratory tract infections preceding the blunt trauma were associated with the gas gangrene.
In conclusion, we encountered a case of human fulminant gas gangrene caused by C. chauvoei that was exactly identified by genetic characterization. Thus, the possibility of C. chauvoei should be considered hereafter in human gas gangrene cases diagnosed as caused by C. septicum, a species that is difficult to distinguish from C. chauvoei by the routine clinical microbiology laboratory tests. C. chauvoei may well be recognized as a new zoonotic pathogen.
We are indebted to Shun Ozawa of the Funabashi Municipal Medical Center for incisive medical advice.
Published ahead of print on 6 February 2008. ![]()
N.N., S.I., and H.K. contributed equally to this work. ![]()
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