Question

Ch. 18-Cardiovascular Infections A 39 year-old intravenous heroin user (who was also actively using cocaine on the date of admission) was admitted with cellulitis on the right arm after experiencing fevers for several weeks. He had been treated with outpatient antibiotics without relief of either associated chills or dizziness. Two sets of blood were obtained upon admission. A trans-thoracic echocardiogram demonstrated a 1 cm vegetation on the ventral surface of the aortic valve. The patient left the hospital against medical advice, but was re-admitted two days later for antimicrobial therapy. Past medical history was notable for multiple hospital admissions for both cellulitis and abscesses primarily involving the patient's arm. He had multiple drug rehabilitation treatment attempts without success. Physical examination demonstrated a thin, unkempt man in no acute distress with multiple "needle track" marks on both lower and upper extremities. No splinter hemorrhages or signs of embolic phenomena were noted on the extremities. The cardiac exam was notable for a grade IIVI systolic murmur best heard at the left sternal border. The spleen tip was palpable. The right arm had a 10x6 cm excoriated area with surrounding induration. A Gram stain of the organism is shown in Figure 1, Growth of the organism on 5% sheep's blood is shown in Figure 2. The organism grew m broth containing 65% NaCl, and was capable of hydrolyzing esculin in the presence of bile. The organism was also catalase-negative. 5 Figure : Gram stain of unknown Figure 2: Growth of organisma on 5% ВАР. ybemolytie. organism under 1000x TM Questions: 1. What type of infection does this man have? I do not what the etiologic agent YET, I want the disease. 2. What organisms frequently cause this condition in IV-drug users? What specific organism is causing this infection? How does IV-drug use predispose the patient to this type of infection? Briefly describe the pathogenesis of the infection. Describe what other organs may secondarily be infected? How do secondary infections oc 3. For what other infectious agents is this person at risk for contracting? 4. 5. When considering antimicrobial therapy for this infection, what strategy should be employed? 6. What antibiotic resistance problems have recently emerged regarding this organism? What strategies have been employed to reduce the spread of this species?

Answer 1

1.The signs and symptoms typically suggest the patient is having a bacterial infection.He has infective endocarditis

2.The organism which usually causes this infection belongs to Staphyllococcus aureus or Streptococci group or cat glass negative staphyllococcus.

Catalyse negative staphyllococcus is the specific organism ca using this disease

3.The main predisposing factor is the infected or unsterile needle used in injection. The use of same needle by multiple persons.

When a individual (IV drug users)inject the drug via vein>>enters the blood stream>>reaches the circulatory system >>enters the heart to disperse and multiply>>valves are affected >>vegetative state of the valves>>called as vascular vegetation >>infective endocarditis (bacterial growth,vegetation and poor immune response)

It may affect the kidney causing kidney failure and brain leading to stroke.This occurs because the infected heart with bacterial growth reaches the main organs via circulation and causing damage to other organs

4.The person is at risk of contracting human immunodeficiency virus due to the use of IV drugs.