Reference no: EM133380054

Case Study: Pavandeep is a 64-year-old male. Over the past 24 hours, Pavandeep has experienced severe abdominal pain, fever, and dehydration. Unable to eat or sleep, he presents to the emergency room of the local hospital. On physical examination, Pavandeep's BP: 90/60, HR: 135, T: 40°C, and RR: 32 with an oxygen saturation level of 95% on room air. Pavandeep has cool clammy skin and diffuse abdominal tenderness with guarding. Laboratory evaluation reveals a white blood cell (WBC) count of 16,000 cells/mm 3
. Initial treatment includes resuscitation with fluids, and empiric antibiotic therapy (ampicillin-sulbactam and levofloxacin). An abdominal CT is ordered, and reveals a right lower quadrant mass. Pavandeep is urgently taken to the operating room. At the time of surgery, he is found to have a perforated appendix with gross fecal contamination of the peritoneum. By the second postoperative day, Pavandeep is afebrile, and his WBC count gradually decreases into the normal range. Pavandeep is then transferred from the intensive care unit to a medical/surgical ward on postoperative day 3. Ampicillin-sulbactam and levofloxacin antibiotic therapy is continued. On postoperative day 10, Pavandeep develops a fever of 39.5°C. Once again, his WBC count becomes elevated (14,000 cells/mm3 ). An abdominal CT scan reveals no abscess or fluid collection. A chest x-ray reveals a new right mid-lung infiltrate with small changes to the right lower lobe. A Gram stain of Pavandeep's sputum demonstrates Gram-positive cocci in clusters. In light of this information, ampicillin-sulbactam and levofloxacin therapy is discontinued, and imipenem-cilastatin and vancomycin therapy is initiated. 48 hours later, the medical microbiology laboratory reports that the culture of Pavandeep's sputum grew methicillin-resistant Staphylococcus aureus (MRSA). Despite the change in antibiotic therapy, Pavandeep's fever persists and his WBC count remains above 14,000 cells/mm3. Due to concerns that Pavandeep may have developed a fungal super-infection, empiric fluconazole therapy is added to the treatment regimen. After 6 days of therapy, a repeat abdominal CT was found to be unchanged. Scanning to the chest revealed persistent alveolar infiltrates. Based on these results, vancomycin was empirically changed to linezolid (600 mg IV Q12H). After 2 days of linezolid therapy, Pavandeep was afebrile, with a WBC count in the normal range. Pavandeep was subsequently discharged after 6 days of IV linezolid therapy, completing the remainder of the 10 day course of therapy with oral linezolid (600 mg PO Q12H)

Question: Explain in detail, What pathogen caused the infection? In detail What is the pathogenesis of this infection? How did Pavandeep develop MRSA?