Clostridium

CASE 1

• A 46 year old male construction company supervisor was brought to the Emergency Department after falling ~4 meters onto an iron reinforcing rod at a construction site. The rod penetrated the muscles of the right shoulder and caused a laceration of the skin. The patient had been told that he was diabetic many years earlier but was on no treatment.

• The wound is sutured closed and bandaged. A pain killer and an oral antibiotic is prescribed (the patient took the pain killer). However, the returns 48 hours later with extreme pain and tenderness of the entire right shoulder and a fever of 39.5C. There is a “crunchy” sensation under the affected skin, and there is a thin watery drainage from the wound. A routine bacterial culture is negative.

• An xray of the shoulder shows gas in the tissues under the affected skin. A gram stain of the discharge is shown below. The patient was hospitalized urgently and treated with high-dose penicillin. He underwent several extensive debridements of devitalized muscle and skin Eventually, he required amputation of the right upper extremity and major reconstructive surgery.

Questions:

    1. Where did these bacteria come from?
    2. Why were they at a construction site?
    3. Why are there no intact PMNs in the pus?
    4. Why is there gas in the tissue?
    5. Why is the culture negative?
    6. Why is this infection so aggressive in this patient?
    7. Why was it necessary to do repeated surgery if antibiotics are active against the bacteria?

 

CASE 2

• A 38 year old farmer was admitted to the hospital with generalized stiffness and periodic muscle spasms. Five days earlier, he had sustained a cut of the right ankle while working in his fields. The site of this injury is now slightly swollen and mildly tender with some thin drainage from the wound. The patient has no history of childhood vaccination.

• The temperature was 37.1 degrees. The heart rate was 105/min. The patient was asked to open his mouth, and the photo below shows the result of his best effort.

Questions:

    1. This disease is caused by what organism?
    2. Where in the patient's body who you expect to find this organism?
    3. What bacterial factor is responsible for the tetany of the muscles?
    4. What is the mechanism of the toxicity on the nerve endings?
    5. How can this disease be prevented?
    6. Does vaccination prevent infection with the causative Clostridial species? If not, how does vaccine protect?

 

CASE 3

• A 10 day old newborn male develops spastic rigidity of the face, neck and back. Minimal movement of the infant’s cradle causes repetitive whole body spasms.

• On examination, the infant has a heart rate of 140/min but is afebrile. The blood pressure is normal and stable. The umbilical stump appears moist and cyanotic. The neonate is intensely rigid with all muscle groups in spasm.

.

• The infant was treated for neonatal tetanus with antiserum and antibiotics. On the fifth hospital day, the infant succumbed to overwhelming pneumonia.

Questions:

    1. Where would you expect to find the causative organism in this patient?
    2. How is this disease similar to the illness described in Case 2 above?
    3. How could this illness have been prevented?

 

CASE 4

• A 14 year old boy fractured his ulna and radius after a fall while paying football. The bones were set in the Emergency Department and a plaster cast was applied. Five days later, the boy began having difficult speaking and swallowing. He complained of double vision, followed by weakness in both hands.

• After a full examination, now source of infection was found. Accordingly, the cast was removed and wound with the following appearnce was observed (see below).

.

• The wound was extensively debrided. The boy was treated with specific antiserum, respiratory support, and an appropriate antibiotic. He recovered after 3 weeks in the hospital.

Questions:

    1. What is the likely microbial cause of this syndrome?
    2. How is the toxicity of this pathogen different from C. tetani?
    3. How else could this condition have been acquired?

 

CASE 5

•An 81-year-old man has a fever of 38.5°C for 5 days. He was previously well, except for dementia and hospitalization for a urinary tract infection 4 weeks ago. At that time, he was given a 10 day course of ampicillin.

• On examination, he was comfortable, but confused. his temperature was 39°; the other vital signs were normal. There were no localized physical findings, and his abdominal examination was normal. A WBC count was 25,000/mm3

• He was admitted again to the hospital, and the next morning, a staff nurse noted that the patient had passed two loose bowel movements during the night and another in the morning. A stool specimen was positive for occult blood. A bedside proctoscopic examination was performed and white-yellow membranes were seen covering the normal rectal mucosa (below).

.

• Treatment was begun with oral metronidazole. The patient became afebrile within 36 hours, and he returned to his nursing home without further laboratory investigations within 72 hours.

Questions:

    1. Where do the Clostridia that cause this disorder most likely come from? What is the infectious particle that is ingested?
    2. Is the history of previous treatment with ampicillin pertinent to symptomatic C. difficile infection? In what way?
    3. What caused the patient's symptom and the development of the pseudomembranes in the colon    ?
    4. Could this illness have been fatal? Can it result in an emergency colectomy?