final program.qxd - Parallels Plesk Panel

PP 6.17
Community-acquired septicemic pneumonia caused by a multiresistant
Staphylococcus aureus strain, resulting in multiple organ involvement exacerbated
by extensive immune activation
Roberto Manfredi, Sergio Sabbatani
Infectious Diseases, University of Bologna, Italy
Introduction
Antibiotic-resistant gram-positive cocci are of increasing concern, and immune activation
promped by microbial products (bacterial superantigens) may play a major role in the
pathogenesis of disseminated, life-threatening Staphylococcus aureus infection.
Patient and Methods
An exceptional case report of community-acquired, severe infection caused by a
methicillin-resistant S. aureus strain,responsible for pneumonia, septic shock, and
scattered septic embolism, and accompanied by diffuse polyvisceritis and thrombophlebitis
as signs of an extensive immune system activation, was seen in a otherwise healthy
40-year-old man.
Results
The striking features of S. aureus polyvisceral disease (pneumonia, septicemia, and
pulmonary and hepato-splenic septic embolism), were associated with multiple
immune-mediated focal manifestations (massive pleuric-pericardial effusion, mycocarditis,
and multiple lower limb thrombophlebitis). In vitro resistance to all beta-lactams,
fluoroquinolones, macrolides, and aminoglycosides, apparently did not justify the
clinical-microbiological failure of a glycopeptide-based combination therapy. Only the
administration of combined linezolid-rifampicin-tetracycline together with intensive care
support, achieved a slowly progressive ameliorement, while the polyvisceritis (associated
by an immune-activation syndrome documented by increased CD4+, CD34+, and CD4-
CD8- T-lymphocyte subsets), caused dysreactive disease at multiple body sites, and
required a prolonged high-dose steroid therapy. A complete clinical, laboratory, and
instrumental recovery was reached only three months after admission.
Conclusions
This report raises multiple questions about the epidemiology, pathogenesis, clinical
presentation and manifestations, and management of complicated S. aureus infection,
with special focus on the immune system activation possibly triggered by microbial
antigens, and the therapeutic role of steroids and novel antibiotics targeted against
resistant gram-positive cocci.
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