An uncommon presentation for a severe invasive infection due to methicillin-resistant Staphylococcus aureus clone USA300 in Italy: a case report.
BACKGROUND
Methicillin resistant Staphylococcus aureus (MRSA) has been considered for many years a typical nosocomial pathogen. Recently MRSA has emerged as a frequent cause of infections in the community. More commonly, community-acquired (CA)-MRSA is a cause of infections of the skin and soft-tissues, but life-threatening infections such as necrotizing pneumonia and sepsis can occasionally occur.


METHODS
This report describes an uncommon presentation of invasive CA-MRSA infection in an adolescent without known risk factors. The presentation was typical for bacterial meningitis, but the clinical findings also revealed necrotizing pneumonia. Following the development of deep venous thrombosis, the presence of an inherited thrombophilic defect (factor V Leiden) was detected. The patient was successfully treated with an antibiotic combination including linezolid and with anticoagulant therapy. CA-MRSA was isolated from both cerebrospinal fluid and blood. The isolates were resistant to oxacillin and other beta-lactam antibiotics and susceptible to the other antibiotics tested including erythromycin. Molecular typing revealed that the strains contained the Panton-Valentine leukocidin genes and type IV SCCmec, and were ST8, spa type t008, and agr type 1. This genetic background is identical to that of the USA300 clone.


CONCLUSIONS
This report highlights that meningitis can be a new serious presentation of CA-MRSA infection. CA-MRSA strains with the genetic background of the USA300 clone are circulating in Italy and are able to cause severe infections.
Valentini
Piero
P
Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. pvalentini@rm.unicatt.it
Parisi
Gabriella
G
Monaco
Monica
M
Crea
Francesca
F
Spanu
Teresa
T
Ranno
Orazio
O
Tronci
Mirella
M
Pantosti
Annalisa
A
D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000209:etiology*; D004359:Drug Therapy, Combination; D005165:Factor V / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000209:etiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics; D020246:Venous Thrombosis / Q000209:etiology
D000900:Anti-Bacterial Agents; C095381:factor V Leiden; D005165:Factor V