Journal of clinical microbiology
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J. Clin. Microbiol. · Jul 2006
Comparative StudyDiagnosis of streptococcal pharyngitis by detection of Streptococcus pyogenes in posterior pharyngeal versus oral cavity specimens.
Carbohydrate antigen detection, nucleic acid probe detection, and bacterial culture are commonly used to confirm group A streptococcus (GAS) pharyngitis. Compared to standard throat swab specimens, the sensitivities of these tests with mouth specimens are poor. When testing for GAS pharyngitis, the throat remains the optimum site for sampling.
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J. Clin. Microbiol. · Jul 2006
Comparative StudyComparison of multilocus sequence typing, pulsed-field gel electrophoresis, and antimicrobial susceptibility typing for characterization of Salmonella enterica serotype Newport isolates.
In the United States, multidrug-resistant phenotypes of Salmonella enterica serotype Newport (commonly referred to as MDR-AmpC) have emerged in animals and humans and have become a major public health problem. Although pulsed-field gel electrophoresis (PFGE) is the current "gold standard" typing method for Salmonella, multilocus sequence typing (MLST) may be more relevant to investigations exploring evolutionary and population biology relationships. In this study, 81 Salmonella enterica serotype Newport isolates from humans, food animals, and retail foods were examined for antimicrobial susceptibility and characterized using PFGE and MLST of seven genes, aroC, dnaN, hemD, hisD, purE, sucA, and thrA. ⋯ Ten new sequence types and one novel allele type were identified. Furthermore, MLST typing showed that strains closely related by PFGE clustered in major STs, whereas more distantly related strains were separated into two clusters by PFGE. The results of this study demonstrated that the MLST scheme employed here clustered S. enterica serovar Newport isolates in distinct molecular populations, and strain discrimination was enhanced by combining PFGE, antimicrobial susceptibility, and MLST results.
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J. Clin. Microbiol. · Jul 2006
Genetic differentiation of Chinese isolates of Rickettsia sibirica by partial ompA gene sequencing and multispacer typing.
Current data on rickettsiae and rickettsial diseases in China remain limited. Using partial ompA gene sequencing and multispacer typing, we identified 15 rickettsial isolates from China. All isolates were found to belong to Rickettsia sibirica subsp. sibirica. ⋯ All 11 remaining isolates were similar to the R. sibirica subsp. sibirica type strain, 246. These were widely distributed in China in humans and different tick species. We emphasize the importance of surveying the distribution of R. sibirica in China.
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J. Clin. Microbiol. · Jul 2006
Macrorestriction analysis of clinical and environmental isolates of Sporothrix schenckii.
Sporothrix schenckii causes sporotrichosis, a disease that most commonly presents as a subacute or chronic skin infection. An unusually high incidence of clinical cases of sporotrichosis occurred in the southwest of Western Australia over the last 5 years. Anecdotal accounts from patients implicated contact with hay prior to infection. ⋯ Clinical isolates from the southwest of Western Australia collected in the 1980s and 1990s were also characterized using PFGE. The patterns generated were indistinguishable from those of the recent clinical isolates. PFGE showed that the dominant strain of S. schenckii causing sporotrichosis in Western Australia is present in hay, has caused sporotrichosis for at least 15 years, and is a different strain from the strains found in other parts of Australia.
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J. Clin. Microbiol. · Jun 2006
Genetic determinants and polymorphisms specific for human-adapted serovars of Salmonella enterica that cause enteric fever.
Salmonella enterica serovars Typhi, Paratyphi A, and Sendai are human-adapted pathogens that cause typhoid (enteric) fever. The acute prevalence in some global regions and the disease severity of typhoidal Salmonella have necessitated the development of rapid and specific detection tests. Most of the methodologies currently used to detect serovar Typhi do not identify serovars Paratyphi A or Sendai. ⋯ These polymorphisms and loci were developed into real-time PCR, standard PCR, and liquid microsphere suspension array-based molecular protocols and tested for with a panel of clinical and reference subspecies I S. enterica strains. A proportion of the nontyphoidal Salmonella strains hybridized with the allele-specific oligonucleotide probes for sseC and sseF; but the trpS allele was unique to serovar Typhi (with a singular serovar Paratyphi B strain as an exception), and the coding sequences STY4220 and STY4221 were unique among serovars Typhi, Paratyphi A, and Sendai. These determinants provided phylogenetic data on the genetic relatedness of serovars Typhi, Paratyphi A, and Sendai; and the protocols developed might allow the rapid identification of these Salmonella serovars that cause enteric fever.