Streptococcal Biology & Biofilm - Parham Sendi

Invasive group B Streptococcus infections in nonpregnant adults

Group B Streptococcus (GBS) is a major cause of sepsis in neonates and pregnant women. The incidence of invasive GBS disease in nonpregnant adults is growing, in particular in elderly persons and in those with chronic underlying conditions (e.g. diabetes mellitus). Cases of infective endocarditis, prosthetic joint infections, or of severe, life-threatening syndromes of necrotizing fasciitis and toxic shock syndrome due to GBS are increasingly reported.

This epidemiological shift is associated with two major uncertainties, namely in pathogenesis and clinical management. Firstly, the development of invasive GBS disease is based on bacterial colonization (e.g. of the vaginal epithelium), penetration of epithelial barriers and invasion into sterile compartments. However, – in comparison to pregnant women and neonates –, in the elderly, this process requires other environmental conditions. Secondly, because treatment concepts in adults are not established, those used for neonates – i.e., the combination of beta-lactams plus an aminoglycoside – are transferred to adults. Though, adults, especially elderly persons, are more prone to develop side effects caused by aminoglycosides (e.g., nephrotoxicity and ototoxicity) than are neonates. Our research focuses on the pathogenesis, clinical picture and treatment concepts of invasive group B Streptococcus infections in nonpregnant adults.

Minimal Biofilm Eradication Concentration

Foreign body infections are increasingly recognized as a major health care problem. Bacteria adhere to the foreign body and form a biofilm that is difficult to eradicate. As a consequence, the device must be removed. In certain clinical condition, such an intervention is not possible or associated with significant collateral damage. Our research targets a reliable determination of minimal biofilm eradication concentration of a given antimicrobial agents. In parallel, we measure (in our institution or in collaboration) antibiotic levels in human serum to evaluate whether or not these levels can be achieved in vivo.