VIENNA (FRONTLINE MEDICAL NEWS) – A 6-week course of antibiotics, with an early switch from intravenous to oral, appears to be a safe and appropriate option for some patients with pyogenic vertebral osteomyelitis.

A single-center retrospective study of 82 such patients found two treatment failures and two deaths over 1 year (4.8% failure rate). The patients who died were very elderly with serious comorbidities. The two treatment failures occurred in patients with methicillin-resistant coagulase-negative staphylococcal infections of a central catheter.

“Only two of the failures were due to inadequate antibiotic treatment,” Adrien Lemaignen, MD, said at the European Society of Clinical Microbiology and Infectious Diseases annual congress. “Both patients experienced a relapse of bacteremia with the same bacteria a few days after antibiotic cessation in a context of conservative treatment of a catheter-related infection.”

Guidelines recently adopted by the Infectious Diseases Society of America inspired the study, said Dr. Lemaignen of University Hospital of Tours, France. The 2015 document calls for 6-8 weeks of antibiotics, depending upon the infective organism and whether infective endocarditis complicates management. All suggested antibiotic regimens call for initial IV therapy followed by oral, but there are no cut-and-dried recommendations about when to switch. The guideline notes one study in which patients switched to oral after about 2.7 weeks, with a 97% success rate.

Dr. Lemaignen and his colleagues set out to determine cure rates of early oral relay in 82 patients with pyogenic vertebral osteomyelitis (PVO). All patients were treated at a single center from 2011 to 2016. The team defined treatment failure as death, or persistence or relapse of infection in the first year after treatment.

All patients had culture-proven PVO that also was visible on imaging. Patients were excluded if they had any brucellar, fungal, or mycobacterial coinfections, or if they had infected spinal implants.

The mean age of the patients in the cohort was 66 years; 39% had some neuropathology. The mean C-reactive protein level was 115 mg/L. More than half of the cases (56%) involved the lumbar-sacral spine; 30% were thoracic, and the remainder, cervical. About one-fifth had multiple level involvement. There was epidural inflammation in 68%, epidural abscess in 13%, and extradural abscess in 26%.

Staphylococcus aureus was the most common pathogen (34%); two infections were methicillin resistant. Other infective organisms were streptococci (27%), Gram-negative bacilli (15%), and coagulase-negative staph (12%). A few patients had enterococci (5%) or polymicrobial infections (7%).

Infective endocarditis was present in 16 patients; this was associated with enterococcal and streptococcal infections.

Treatment varied by pathogen. Patients with S. aureus received penicillin or cefazolin with an oral relay to fluoroquinolone/rifampicin or clindamycin. Those with streptococci received amoxicillin with or without an aminoglycoside, followed by oral amoxicillin or clindamycin. Those with coagulase-negative streptococci received a glycopeptide with or without blasticidin, followed by fluoroquinolone/rifampicin. Patients with enterococcal infections got a third generation cephalosporin followed by an oral third generation cephalosporin or a fluoroquinolone.

All but six patients received 6 weeks of treatment.

The mean oral relay occurred on day 12, but 30 patients (36%) were able to switch before 7 days elapsed. Thirteen patients had to stay on the IV route for their entire treatment; 25% of this group had infective endocarditis. Six patients, all of whom had motor symptoms, also needed surgery.

The median follow-up was 358 days. During this time, there were two deaths and two treatment failures.

One death was a 93-year-old who had a controlled sepsis, but died at day 79 of a massive hematemesis. The other was an 80-year-old with an amoxicillin-resistant staph infection and decompensated cirrhosis who died at day 49.

There were also two treatment failures. Both of these patients had methicillin-resistant coagulase-negative staph infections of indwelling central catheters. One had a relapse 70 days after the end of IV therapy; the other relapsed on day 26 of treatment, after a 2-week course of oral antibiotics.

Not all patients were able to succeed with 6 weeks of therapy. Three needed prolonged treatment: One of these had an infected vascular prosthesis and two were immunocompromised patients who had cervical osteomyelitis with multiple abscesses.

In light of these results, Dr. Lemaignen said, “We can say confirm the safety of short IV treatment with an early oral relay in pyogenic vertebral osteomyelitis under real-life conditions, with 95% success rate and good functional outcomes at 6 months.”

He had no relevant financial disclosures.

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