Association between high vancomycin minimum inhibitory concentration and clinical outcomes in patients with methicillin-resistant Staphylococcus aureus bacteraemia - A retrospective cohort study.

The purpose of this study is to determine the role of high (≥ 1.5 mg/L) vancomycin minimum inhibitory concentration (VMIC) in predicting clinical outcomes in patients with methicillin-resistant Staphylococcus aureus bacteraemia (MRSAB). A retrospective study was conducted at Mayo Clinic, Minnesota. Patients ≥ 18 years with a 3-month follow-up were included. Outcomes were defined as 30-day all-cause in-hospital mortality, median duration of bacteraemia, metastatic infectious complications, and relapse of MRSAB. A total of 475 patients with MRSAB were identified, and 93 (19.6%) of them had high VMIC isolates. Sixty-four percent of patients were male with a mean age of 69.0 years. Active solid organ malignancy and skin and soft tissue infection as source of MRSAB were associated with high VMIC, while septic arthritis as a complication was significantly associated with low VMIC on multivariate analysis. Eighty-one (17.1%) patients died within 30 days of hospitalization, with no significant difference in mortality rates between the two groups. In-hospital mortality, median duration of bacteraemia, and metastatic infectious complications were not significantly associated with high VMIC MRSAB.

Native Vertebral Osteomyelitis in Patients with Staphylococcus Aureus Bacteremia.

BACKGROUND: The purpose of the study was to assess the epidemiology, risk factors and outcomes of native vertebral osteomyelitis (NVO) in patients with Staphylococcus aureus bacteremia (SAB). METHODS: A retrospective institutional review was conducted at Mayo Clinic, Minnesota. Patients aged ≥18 years with SAB who developed NVO from January 1, 2006 to December 31, 2020 were included and 3-month follow-up data were abstracted. Data pertaining to patient demographics, risk factors and outcomes were recorded using REDCap. A 1:2 nested case-control analysis was performed, and controls were matched according to age, sex and year of SAB diagnosis. RESULTS: A total of 103 patients had NVO. A majority (60.2%) of patients was male, with a median age of 62.0 years. Thirty-one (30.1%) cases were caused by methicillin-resistant S. aureus (MRSA). The lumbar spine was most commonly (57.6%) and the most commonly reported comorbid conditions included diabetes mellitus (36.9%) and coronary artery disease (27.2%). Mortality at three-month follow-up was 18.6%. Nested case-control analysis revealed that injection drug use (IDU) and tobacco consumption were significant risk factors associated with NVO, while chronic hemodialysis and chronic liver disease (CLD) were associated with a decreased risk of NVO. CONCLUSIONS: Atherosclerotic vascular disease was prominent in our contemporary cohort with NVO in the setting of SAB. Diabetes mellitus, tobacco consumption, older age and male sex likely contributed to this profile. Because IDU was associated with NVO, an increased number of cases should be anticipated among patients with IDU given the ongoing opioid epidemic in the United States.

Lawsonella clevelandensis: an emerging cause of vascular graft infection.

Lawsonella clevelandensis, an emerging pathogen, was first described in 2016, and has been implicated in abdominal, breast and spinal abscesses in a limited number of cases. Being a fastidious organism, it is primarily identified with molecular methods. With the incorporation of broad-range PCR testing in clinical diagnostics, L. clevelandensis has been increasingly reported in the literature. We describe a case of a 65-year-old man who presented with bilateral psoas abscesses secondary to aorto-bi-iliac vascular graft infection with L. clevelandensis identified using 16S rRNA/PCR sequencing. The patient underwent surgical resection and replacement of infected graft, followed by 6 weeks of intravenous antibiotic therapy and then chronic suppression with doxycycline and cefadroxil. He was infection-free at last follow-up.