Chapter 135. Gas Gangrene and Other Clostridial Infections (Part 2) doc

Gas Gangrene and Other Clostridial Infections Part 2 Clinical Manifestations Intestinal Disorders Food Poisoning C.. perfringens, primarily type A, is the second or third most commo

Chapter 135 Gas Gangrene and Other

Clostridial Infections

(Part 2)

Clinical Manifestations

Intestinal Disorders

Food Poisoning

C perfringens, primarily type A, is the second or third most common cause

of food poisoning in the United States (Chap 122) The responsible toxin is thought to be a cytotoxin produced by >75% of strains isolated from cases of food-borne disease The cytotoxin binds to a receptor on the small-bowel brush border and induces a calcium ion–dependent alteration in permeability The associated loss of ions alters intracellular metabolism, resulting in cell death Outbreaks generally have resulted from problems in the cooling and storage of food cooked

in bulk The food sources primarily involved are meat, meat products, and poultry

Generally, the implicated meats have been cooked, allowed to cool, and then

recooked the following day, often in a stew or hash Strains of C perfringens that

contaminate meat manage to survive initial cooking During reheating, the organisms sporulate and germinate The disease is associated with an attack rate that is often as high as 70% Symptoms of food poisoning from type A strains develop 8–24 h after ingestion of foods heavily contaminated with the organism The primary symptoms include epigastric pain, nausea, and watery diarrhea usually lasting 12–24 h Fever and vomiting are uncommon Molecular methods including ribotyping and pulsed-field gel electrophoresis have been used to detect

fecal cytotoxin in outbreaks of food poisoning caused by C perfringens

C perfringens has also been implicated in a more severe form of diarrhea

than that of classic food poisoning This more severe disease tends to occur in the elderly and has been associated with antibiotic use in hospitalized populations In this form of disease, diarrhea is generally more profuse, of longer duration, and accompanied by abdominal pain Blood and mucus have been detected in the feces

of the affected patients In one hospital-based study of a cluster of cases,

widespread environmental contamination with C perfringens spores was

documented

Enteritis Necroticans

Necrotizing enteritis (enteritis necroticans, or pigbel) is caused by β toxin produced by type C strains of C perfringens following ingestion of a high-protein

meal in conjunction with trypsin inhibitors (e.g., in sweet potatoes) by a susceptible host who has limited intestinal proteolytic activity This disease has been reported among children and adults in New Guinea A similar disease,

darmbrand, was epidemic in Germany after World War II Clinical features of

pigbel include acute abdominal pain, bloody diarrhea, vomiting, shock, and peritonitis; 40% of patients die Pathologic studies reveal an acute ulcerative process of the bowel restricted to the small intestine The mucosa is lifted off the submucosa, with the formation of large denuded areas Pseudomembranes composed of sloughed epithelium are common, and gas may dissect into the submucosa The source of the organisms may be the patient's own intestinal flora; cultures of ingested pork have failed to yield the organism Antibodies to the β

toxin of C perfringens have been of considerable benefit in changing the course of established disease In a large-scale trial, children immunized with C perfringens

β toxoid were protected

Neutropenic Enterocolitis (Typhlitis)

See Chaps 82 and 157

Suppurative Deep-Tissue Infections

Clostridia are frequently recovered from various suppurative conditions in conjunction with other anaerobic and aerobic bacteria but can also be the only organisms isolated These suppurative conditions, which exist with severe local inflammation but usually without the characteristic systemic signs induced by clostridial toxins, include intraabdominal sepsis, empyema, pelvic abscess, subcutaneous abscess, frostbite with gas gangrene, infection of a stump in an amputee, brain abscess, prostatic abscess, perianal abscess, conjunctivitis, infection of a renal cell carcinoma, and infection of an aortic graft

Clostridia are isolated from approximately two-thirds of patients with

intraabdominal infections resulting from intestinal perforation C ramosum, C

perfringens, and C bifermentans are the most commonly isolated species The

presence of clostridial species does not affect the clinical presentation or outcome

of these infections (Chap 157)

An association has been made between malignancy and the isolation of C

septicum in the absence of a grossly contaminated deep traumatic wound; in this

situation, C septicum may cause spontaneous nontraumatic myonecrosis (Fig

135-1) A major site for such a malignancy is the gastrointestinal tract, particularly the colon An association with leukemia or with other solid tumors has also been noted, and one case of fatal myonecrosis has been reported in a patient with

ovarian cancer Some of these patients present with C septicum bacteremia; these

cases have a fulminant clinical course (discussed below) Others develop localized

suppurative infection in the abdomen or the abdominal wall without bacteremia Presumably, this infection arises from a silent perforation that leads to intraabdominal abscess formation

Figure 135-1