1. Antibiotic Resistance Develops in a Diabetic Patient Case Study Vancomycin-re
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1. Antibiotic Resistance Develops in a Diabetic Patient Case StudyVancomycin-resistant *Staphylococcus aureus *(VRSA) was isolated from the exit site of a dialysis catheter in a 40-year-old diabetic with a history of peripheral vascular disease, chronic renal failure, and chronic foot ulcers. A few months earlier, the patient’s gangrenous toe had been amputated. Following that surgery, the patient developed bacteremia with methicillin-resistant *S. aureus *from an infected hemodialysis graft. Vancomycin, rifampin, and graft removal successfully treated the infection.
A few months later, when the catheter exit site infection appeared, the
area was cultured and the catheter removed, successfully treating the infection. A week later, the patient’s chronic foot ulcer again appeared infected. Vancomycin-resistant *Enterococcus faecalis *(VRE) and *Klebsiella oxytoca *were cultured from the ulcer. The patient recovered after wound care and systemic treatment with trimethoprim/sulfamethoxazole.
Analysis of the VRSA isolate revealed that it contained the *van *A gene for vancomycin resistance and the *mec *A gene for oxacillin resistance.
A) *How do you think the *Staphylococcus aureus *strain ended up
with the gene for vancomycin resistance?*
B) *What is one possible mechanism for genetic transfer of antibiotic resistance from one organism to another?*
C)Why would this particular patient be at increased risk for infection with VRSA?* 1. Antibiotic Resistance Develops in a Diabetic Patient Case Study
Vancomycin-resistant *Staphylococcus aureus *(VRSA) was isolated from the exit site of a dialysis catheter in a 40-year-old diabetic with a history of peripheral vascular disease, chronic renal failure, and chronic foot ulcers. A few months earlier, the patient’s gangrenous toe had been amputated. Following that surgery, the patient developed bacteremia with methicillin-resistant *S. aureus *from an infected hemodialysis graft. Vancomycin, rifampin, and graft removal successfully treated the infection.
A few months later, when the catheter exit site infection appeared, the
area was cultured and the catheter removed, successfully treating the infection. A week later, the patient’s chronic foot ulcer again appeared infected. Vancomycin-resistant *Enterococcus faecalis *(VRE) and *Klebsiella oxytoca *were cultured from the ulcer. The patient recovered after wound care and systemic treatment with trimethoprim/sulfamethoxazole.
Analysis of the VRSA isolate revealed that it contained the *van *A gene for vancomycin resistance and the *mec *A gene for oxacillin resistance.
A) *How do you think the *Staphylococcus aureus *strain ended up
with the gene for vancomycin resistance?*
B) *What is one possible mechanism for genetic transfer of antibiotic resistance from one organism to another?*
C)Why would this particular patient be at increased risk for infection with VRSA?* 1. Antibiotic Resistance Develops in a Diabetic Patient Case Study
Vancomycin-resistant *Staphylococcus aureus *(VRSA) was isolated from the exit site of a dialysis catheter in a 40-year-old diabetic with a history of peripheral vascular disease, chronic renal failure, and chronic foot ulcers. A few months earlier, the patient’s gangrenous toe had been amputated. Following that surgery, the patient developed bacteremia with methicillin-resistant *S. aureus *from an infected hemodialysis graft. Vancomycin, rifampin, and graft removal successfully treated the infection.
A few months later, when the catheter exit site infection appeared, the
area was cultured and the catheter removed, successfully treating the infection. A week later, the patient’s chronic foot ulcer again appeared infected. Vancomycin-resistant *Enterococcus faecalis *(VRE) and *Klebsiella oxytoca *were cultured from the ulcer. The patient recovered after wound care and systemic treatment with trimethoprim/sulfamethoxazole.
Analysis of the VRSA isolate revealed that it contained the *van *A gene for vancomycin resistance and the *mec *A gene for oxacillin resistance.
A) *How do you think the *Staphylococcus aureus *strain ended up
with the gene for vancomycin resistance?*
B) *What is one possible mechanism for genetic transfer of antibiotic resistance from one organism to another?*
C)Why would this particular patient be at increased risk for infection with VRSA?*
Explanation / Answer
A. The Staphylococcus aureus strain ended up with gene for vancomycin resistance, because of the presence of vancomycin resistance Entercoccus feacalis which appeared after first infection. These bacteria can transferred the van resistance genes to Staphylococcus aureus byy gene transfer methods which will be conjugation process. The resistance genes ar mainly tranferred mainly through transposons present in the plasmid of Enterococcus feacalis which is transferred to Staphylococcus aureus.
B. Since the Staohylococcus aureus reproduces asexually by binary fission, where there is duplication of every molecule of cell are created thus transfers the same data to the duaghter cell. Since both the resistance genes are present on plasmid DNA of cell, therefore on binary fission process there is duplication of plasmid along with the resistant genes, thus providing each resistant copy genes to each cell.
C. Because of presence of vancomycin resistant bacteria Enterococcus feacalis along with the methicillin resistant Staphylocuucus aureus. Since both bacterial traces may be present even though they are treatment is given,but during the period of treatment there is a chance of trasnfer of genes from bacteria to bacteria.
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