**15. Anthrax and** *Bacillus cereus* **infection**

Anthrax is a zoonotic infection of a large-sized Gram-positive bacillus, *Bacillus anthracis* [165–168]. Formation of spores and capsules is closely related to the pathogenicity of the microbe. Three clinical forms are known, involving the skin, lungs, and intestines. The latter two are often lethal. Skin anthrax, predominantly involving the arm, is an occupation-related infection of veterinarians and those who

#### **Figure 57.**

*Neonatal intestinal mucormycosis (H&E, immunostain and Grocott). The premature baby was treated for neonatal necrotizing enterocolitis. Autopsy disclosed necrotic ileal wall with massive transmural infection of* Mucor *fungi. Vascular involvement (mycotic embolism) is evident by both immunostaining with a monoclonal antibody against* Rhizomucor *antigen and Grocott silver. Strong Grocott reactivity is noted in this case.*

treat animal hair, skin, or carcass. The latent period is within 4 days. The skin lesion is necrotic and ulcerated to form hemorrhagic crust (eschar or black necrosis) (**Figure 58**). Characteristically, the ulcer is painless. Gram-positive rods are easily found in the exudate. *B. anthracis* is the best-known bioterrorist, because the spores are tolerant to dry conditions for a long period of time, and inhalation of the spored microorganisms provokes lethal necrotizing pneumonia. Ulcer-forming skin infection is also caused by other *Bacillus* species, such as *B. megaterium* and *B. pumilus* [169].

*Bacillus cereus* is associated mainly with food poisoning, but it may cause potentially fatal non-gastrointestinal infection. The pathogenicity of *B. cereus* is related to the production of tissue-destructive exoenzymes common to *B. anthracis*. *B. cereus* produces a potent β-lactamase, conferring marked resistance to β-lactam antibiotics. Clinically, anthrax-like progressive pneumonia, fulminant sepsis, and devastating central nervous system infections may be seen in immunocompromised individuals, intravenous drug abusers, and neonates. It also occurs in immunocompetent individuals [170]. The primary cutaneous/soft tissue infection of *B. cereus*, mimicking necrotizing fasciitis or non-clostridial gas gangrene induced subsequent to trauma, has been documented [171, 172].

**Figure 59** demonstrates primary necrotizing infection of *B. cereus* in the soft tissue of the hip, as a form of necrotizing fasciitis. Gas formation was not associated in this case. Trauma-related soft tissue gangrene, caused by a spore-forming Grampositive bacillus, *B. cereus*, led this diabetic adult patient to death. Gram-positive rods heavily colonized the necrohemorrhagic muscle tissue.

A 68-year-old housewife received intermittent chemotherapy against lymphoplasmacytic leukemia for 13 years. Her blood contained numbers of indolent small-sized leukemic cells. She happened to take curdled milk, and next day she complained of dyspnea and consciousness disturbance. She expired soon. The

growth of *B. cereus* in fluid milk had provoked sweet curdling [173]. Autopsy disclosed massive hemorrhagic and necrotizing pneumonia caused by *B. cereus* in the right lower lobe. Spore-forming Gram-positive rods were identified in the lesion (**Figure 60**). *B. cereus* antiserum clearly labeled spores in the rod-shaped bacteria. It is highly likely that aspiration of the curdled milk resulted in lethal *B.*

*immunostain). Severe necrotizing hemorrhagic pneumonia was caused by incidental aspiration of sweet-curdled milk. Gram-positive rods grow in the necrotic lesion. The antiserum against* B. cereus *labels spores in the rods.*

*Lethal* Bacillus cereus *pneumonia in a female patient with indolent leukemia (gross, Gram and*

Bacillus cereus*-induced necrotizing fasciitis (H&E, Gram and immunostain). Trauma-related lethal soft tissue gangrene is formed on the hip of the diabetic patient. Gram-positive rods colonize the necrohemorrhagic soft tissue. Immunostaining for* Bacillus cereus *antigens is strongly positive (the courtesy of Dr. Etsuko*

*Nakamura, a pathologist at Toyohashi Medical Center,Toyohashi, Japan).*

The author reviewed pathological aspects of a variety of gangrenous lesions. The causative pathogens are commonly anaerobic. Often times, the lesions are clinically

*cereus* pneumonia.

**135**

**Figure 60.**

**Figure 59.**

*Pathology of Gangrene*

*DOI: http://dx.doi.org/10.5772/intechopen.93505*

**16. Conclusive remarks**

#### **Figure 58.**

*Cutaneous anthrax (gross appearance). Occupation-related infection in a Japanese veterinarian is shown. The lesion of cutaneous anthrax on the left forearm is necrotic and ulcerated to form hemorrhagic crust (eschar). The courtesy by Dr. Keiko Oka, a dermatologist at Tokyo Hospital of Health Insurance Association of Nippon Express,Tokyo, Japan.*

#### **Figure 59.**

treat animal hair, skin, or carcass. The latent period is within 4 days. The skin lesion is necrotic and ulcerated to form hemorrhagic crust (eschar or black necrosis) (**Figure 58**). Characteristically, the ulcer is painless. Gram-positive rods are easily found in the exudate. *B. anthracis* is the best-known bioterrorist, because the spores are tolerant to dry conditions for a long period of time, and inhalation of the spored microorganisms provokes lethal necrotizing pneumonia. Ulcer-forming skin infection is also caused by other *Bacillus* species, such as *B. megaterium* and *B.*

*Bacillus cereus* is associated mainly with food poisoning, but it may cause potentially fatal non-gastrointestinal infection. The pathogenicity of *B. cereus* is related to the production of tissue-destructive exoenzymes common to *B. anthracis*. *B. cereus* produces a potent β-lactamase, conferring marked resistance to β-lactam antibiotics. Clinically, anthrax-like progressive pneumonia, fulminant sepsis, and devastating central nervous system infections may be seen in immunocompromised individuals, intravenous drug abusers, and neonates. It also occurs in immunocompetent individuals [170]. The primary cutaneous/soft tissue infection of *B. cereus*, mimicking necrotizing fasciitis or non-clostridial gas gangrene induced subsequent

**Figure 59** demonstrates primary necrotizing infection of *B. cereus* in the soft tissue of the hip, as a form of necrotizing fasciitis. Gas formation was not associated in this case. Trauma-related soft tissue gangrene, caused by a spore-forming Grampositive bacillus, *B. cereus*, led this diabetic adult patient to death. Gram-positive

lymphoplasmacytic leukemia for 13 years. Her blood contained numbers of indolent small-sized leukemic cells. She happened to take curdled milk, and next day she complained of dyspnea and consciousness disturbance. She expired soon. The

*Cutaneous anthrax (gross appearance). Occupation-related infection in a Japanese veterinarian is shown. The lesion of cutaneous anthrax on the left forearm is necrotic and ulcerated to form hemorrhagic crust (eschar). The courtesy by Dr. Keiko Oka, a dermatologist at Tokyo Hospital of Health Insurance Association of Nippon*

A 68-year-old housewife received intermittent chemotherapy against

*pumilus* [169].

*Pathogenic Bacteria*

**Figure 58.**

**134**

*Express,Tokyo, Japan.*

to trauma, has been documented [171, 172].

rods heavily colonized the necrohemorrhagic muscle tissue.

Bacillus cereus*-induced necrotizing fasciitis (H&E, Gram and immunostain). Trauma-related lethal soft tissue gangrene is formed on the hip of the diabetic patient. Gram-positive rods colonize the necrohemorrhagic soft tissue. Immunostaining for* Bacillus cereus *antigens is strongly positive (the courtesy of Dr. Etsuko Nakamura, a pathologist at Toyohashi Medical Center,Toyohashi, Japan).*

#### **Figure 60.**

*Lethal* Bacillus cereus *pneumonia in a female patient with indolent leukemia (gross, Gram and immunostain). Severe necrotizing hemorrhagic pneumonia was caused by incidental aspiration of sweet-curdled milk. Gram-positive rods grow in the necrotic lesion. The antiserum against* B. cereus *labels spores in the rods.*

growth of *B. cereus* in fluid milk had provoked sweet curdling [173]. Autopsy disclosed massive hemorrhagic and necrotizing pneumonia caused by *B. cereus* in the right lower lobe. Spore-forming Gram-positive rods were identified in the lesion (**Figure 60**). *B. cereus* antiserum clearly labeled spores in the rod-shaped bacteria. It is highly likely that aspiration of the curdled milk resulted in lethal *B. cereus* pneumonia.
