Panton-Valentine leukocidin (PVL) is a virulence factor of Staphylococcus aureus, which is associated with skin and soft-tissue infections and necrotizing pneumonia. To develop a rapid phenotypic assay, recombinant PVL F component was used to generate monoclonal antibodies by phage display. These antibodies were spotted on protein microarrays and screened using different lukF-PV preparations and detection antibodies. This led to the identification of the optimal antibody combination that was then used to establish a lateral flow assay. This test was used to detect PVL in S. aureus cultures. The detection limit of the assay with purified native and recombinant antigens was determined to be around 1 ng/ml. Overnight cultures from various solid and liquid media proved suitable for PVL detection. Six hundred strains and clinical isolates from patients from America, Europe, Australia, Africa, and the Middle East were tested. Isolates were genotyped in parallel by DNA microarray hybridization for confirmation of PVL status and assignment to clonal complexes. The sensitivity, specificity, and positive and negative predictive values of the assay in this trial were 99.7, 98.3, 98.4, and 99.7%, respectively. A total of 302 clinical isolates and reference strains were PVL positive and were assigned to 21 different clonal complexes. In summary, the lateral flow test allows rapid and economical detection of PVL in a routine bacteriology laboratory. As the test utilizes cultures from standard media and does not require sophisticated equipment, it can be easily integrated into a laboratory's workflow and might contribute to timely therapy of PVLassociated infections.
Although the influence of bactibilia in developing surgical complications is limited, its composition and the high rate of resistance can be influential enough to modify antibiotic treatment in biliary tract infections, especially in high-risk patients.
Three types of group A streptococcal infections are particularly feared: necrotizing fasciitis, myositis, and streptococcal toxic shock syndrome (TSS). We present 3 cases of necrotizing fasciitis due to Streptococcus pyogenes, one in an immunocompromised patient who had received kidney transplant and 2 healthy patients. Mean age of patients was 52 years (range, 42-67 years), and all 3 were male. One spontaneous case in absence of any obvious portal of entry is reported. The clinical course was initially indolent but quickly destructive. All patients required emergency surgical debridement and intravenous antibiotics. In 2 cases, intravenous immunoglobulin therapy was added. Differential diagnoses include septic arthritis, cellulitis, gout, other causes of tenosynovitis, erysipelas, and deep vein thrombosis.Blood and soft-tissue cultures should be obtained to identify the bacteria, and emergency computed tomography or magnetic resonance imaging scan should be performed to confirm the diagnosis and define the extension of the necrosis. Aggressive surgical debridement in the first 24 to 48 hours and antibiotic treatment, including penicillin and clindamycin, are the cornerstones in the management of these infections. Adjuvant intravenous immunoglobulin therapy might be useful in case of TSS. Diagnostic and treatment delays are the main causes of mortality in these infections.
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