Serratia Marcescens, a Rare and Devastating Cause of Endocarditis: A Case Report and Review of the Literature.

Serratia marcescens is a gram-negative bacillus that is an opportunistic agent in respiratory tract infections, urinary tract infections, and septicemia. It is rarely a cause of infective endocarditis, but in cases of endocarditis, it follows a rapid and devastating course. A previously healthy female in her mid-50s presented with fever, abdominal pain, right lower extremity pain, and diarrhea. Blood cultures were positive for S. marcescens , and additional evaluation revealed infarction in the spleen and kidneys, raising concern for endocarditis with associated embolic phenomena. The patient was subsequently found to have an embolus in the right popliteal artery and underwent a right popliteal thromboembolectomy. Antimicrobial therapy with cefepime and gentamicin was begun. A transesophageal echocardiogram revealed a large, mobile mitral valve vegetation. Care was complicated by intracranial hemorrhage, and the decision was made to withdraw care. A review of the databases Embase and PubMed revealed 63 additional cases of S. marcescens endocarditis. Analysis of these cases demonstrated a preponderance of aortic and mitral valve involvement, not tricuspid valve involvement, despite a risk factor of intravenous drug use in over 60% of cases. Mortality was 50%, and sequelae such as congestive heart failure and renal insufficiency occurred in the majority of survivors. In conclusion, S. marcescens is a rare but devastating cause of endocarditis with a primary risk factor of intravenous drug use but with a predilection for left-sided valvular lesions, not right-sided lesions.

Pleural Effusion/Empyema With Mycobacterium kansasii.

Mycobacterium kansasii is a nontuberculous mycobacterium that causes pulmonary symptoms, commonly associated with underlying conditions, including malignancy, prior transplant, and HIV. However, rarely does Mycobacterium kansasii present with pleural effusion. We present a case of a 56-year-old female who presented with dyspnea and chest pain, and sputum culture was positive for acid-fast bacilli. A CT scan revealed a left-sided pleural effusion. Based on a thorough review of the literature using Embase and PubMed, we found that only 22 cases of a Mycobacterium kansasii pleural effusion have been reported. We provide a discussion on maintaining a broad differential in the treatment of immunocompromised individuals with Mycobacterium infection.

Bilateral emphysematous pyelonephritis.

A 57-year-old man presenting with bilateral flank pain and hematuria was found to have severe bilateral emphysematous pyelonephritis. The patient was managed with a conservative approach consisting of systemic antimicrobials and decompression via percutaneous nephrostomy tubes with piperacillin-tazobactam instillations via nephrostomy and made a full recovery.

HHV-6: an unusual cause of cerebellar ataxia.

Human herpesvirus 6 (HHV-6) infection is the cause of roseola infantum in children. The reactivation of HHV-6 is associated with multiple clinical syndromes including encephalitis and myelitis, especially in haematopoietic stem cell transplant recipients. However, the virus can cause encephalitis in other immunosuppressed as well as immunocompetent individuals. We report a case of a 70-year-old woman who was immunocompromised secondary to treatment of rheumatoid arthritis with leflunomide and methotrexate. The patient presented with acute ataxia, diplopia and dysarthria. MRI brain showed an enhancing lesion in the midbrain. The diagnosis of HHV-6 encephalitis was made after HHV-6 A DNA was detected in both serum and cerebrospinal fluid. Treatment consisted of a 3-week course of intravenous ganciclovir along with physiotherapy. At a 3-month follow-up, repeat MRI brain showed a decrease in size and oedema of the lesion and the patient's neurological function was improved.