ABSTRACT
INTRODUCTION: Serotype surveillance of Streptococcus pneumoniae is indispensable for evaluating the potential impact of pneumococcal conjugate vaccines. Serotyping by the standard Quellung reaction is technically demanding, time consuming, and expensive. A simple and economical strategy is multiplex PCR-based serotyping. We evaluated the cost effectiveness of a modified serial multiplex PCR (mPCR), resolving 24 serotypes in four PCR reactions and optimally targeting the most prevalent invasive and colonizing pneumococcal serotypes found in Venezuela. METHODOLOGY: A total of 223 pneumococcal isolates, 140 invasive and 83 carriage isolates, previously serotyped by the Quellung reaction and representing the 18 most common serotypes/groups identified in Venezuela, were serotyped with the adapted mPCR. RESULTS: The mPCR serotyped 76% of all the strains in the first two PCR reactions and 91% after four reactions, correctly identifying 17 serotypes/groups. An isolate could be serotyped with mPCR in less than 2 minutes versus 15 minutes for the Quellung reaction, considerably lowering labor costs. A restrictive weakness of mPCR was found for the detection of 19F strains. Most Venezuelan 19F strains were not typeable using the mPCR, and two 19F cps serotype variants were identified. CONCLUSIONS: The mPCR assay is an accurate, rapid, and economical method for the identification of the vast majority of the serotypes from Venezuela and can be used in place of the standard Quellung reaction. An exception is the identification of serotype 19F. In this setting, most 19F strains were not detectable with mPCR, demonstrating a need of serology-based quality control for PCR-based serotyping.
Subject(s)
Carrier State/microbiology , DNA, Bacterial/analysis , Pneumococcal Infections/microbiology , Streptococcus pneumoniae/isolation & purification , Cost-Benefit Analysis , Humans , Polymerase Chain Reaction/economics , Polymerase Chain Reaction/methods , Serogroup , Streptococcus pneumoniae/genetics , Time Factors , VenezuelaABSTRACT
INTRODUCTION: Mesotherapy is widely used In Latin America for cosmetic purposes, particularly in obese individuals. We describe the clinical and epidemiological characteristics, microbiological diagnosis, treatment and follow-up of patients from Caracas (Venezuela) with soft tissue infection caused by non-tuberculous mycobacteria following mesotherapy. METHODS: Between March 2002 and December 2003, we evaluated 49 cases of skin and soft tissue infection following mesotherapy. Specimens obtained from the lesions and 15 products used in the mesotherapy procedure were cultured for the presence of non-tuberculous mycobacteria. Isolated mycobacteria were identified by PCR restriction fragment length polymorphism analysis of the hsp65 gene. RESULTS: Infection by non-tuberculous mycobacteria was confirmed in 81.6% of the 49 cases. Mycobacterium abscessus and M. fortuitum were the most common species, but M. chelonae, M. peregrinum, M. simiae and a new species that was designated "M. cosmeticum" were also isolated. Patients were treated with species-specific antibiotic agents for 3 to 18 months. Investigation into the source of the infection revealed that 21 patients were clustered within 3 different outbreaks and two products were found to be contaminated with M. fortuitum and M. abscessus, respectively. CONCLUSIONS: Physicians should be alerted to the possibility of infection by non-tuberculous mycobacteria in patients with a history of mesotherapy who develop late-onset skin and soft tissue infection, particularly if they do not respond to conventional antibiotic treatment.
