Research Day

Non-hemolytic Group B Streptocoocus as a Cause of Chemotherapy Port Infection

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Introduction: Lancefield group B streptococci(GBS) are common causes of infection in adult with diabetes as well as a classical cause of perinatal meningitis. The organism is a classical beta-hemolytic streptococcus. We present an unusual cause of human infection due to GBS, a chemotherapy port site with bacteremia with an organism without hemolysis (so-called gamma hemolysis), a rare phenotypic manifestation of GBS. Case Report: A 63 year old male was admitted for fever, chills and altered mental status. He had been recently diagnosed with pancreatic carcinoma and had had a stent placed in his common bile duct. One week before admission, a chemotherapy port was placed and on admission had no local signs and symptoms of infection and had not started chemotherapy. He was febrile, his WBC was 15K and he had no clear focal findings on physical examination and chest and abdominal imaging. 2 blood cultures were positive for Gram positive cocci in pairs and chains which revealed a gamma (or non-) hemolytic streptococcus that was subsequently identified as a Group B streptococcus. In the absence of another source, the port was explanted and the patient recovered without further positive cultures. Conclusion: We present an unusual case of GBS infection causing a infusion port infection with an organism that was nonhemolytic. Nonhemolytic GBS represent only 1-3% of GBS and are generally are caused by mutations in a transporter that normally exports the hemolysin extracellularly. The mutation is also associated with the lack of GBS orange/red pigment production. These nonhemolytic GBS isolates are generally considered to be less virulent but not nonpathogenic. It is important to remember that nonhemolytic streptococci can be pathogenic and may be part of GBS that are usually beta-hemolytic.

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