2 research outputs found
Correlation between Group B Streptococcal Genotypes, Their Antimicrobial Resistance Profiles, and Virulence Genes among Pregnant Women in Lebanon
The antimicrobial
susceptibility profiles of 76
Streptococcus agalactiae (Group
B Streptococci [GBS]) isolates from vaginal
specimens of pregnant women near term were
correlated to their genotypes generated by
Random Amplified Polymorphic DNA analysis and
their virulence factors encoding genes
cylE, lmb, scpB, rib, and bca
by PCR. Based on the distribution of the
susceptibility patterns, six profiles were
generated. RAPD analysis detected 7 clusters of
genotypes. The cylE gene was
present in 99% of the isolates, the
lmb in 96%,
scpB in 94.7%,
rib in 33%, and
bca in 56.5% of isolates.
The isolates demonstrated a significant
correlation between antimicrobial resistance and
genotype clusters denoting the distribution of
particular clones with different antimicrobial
resistance profiles, entailing the practice of
caution in therapeutic options. All virulence
factors encoding genes were detected in all
seven genotypic clusters with
rib and bca
not coexisting in the same
genome
Evaluation of a Multilocus Variable-Number Tandem-Repeat Analysis Scheme for Typing Human Brucella Isolates in a Region of Brucellosis Endemicity▿ †
Brucellosis remains an important anthropozoonosis worldwide. Brucella species are genetically homogeneous, and thus, the typing of Brucella species for epidemiological purposes by conventional molecular typing methods has remained elusive. Although many methods could segregate isolates into the phylogenetically recognized taxa, limited within-species genetic diversity has been identified. Recently, multilocus variable-number tandem-repeat analysis (MLVA) was found to have a high degree of resolution when it was applied to collections of Brucella isolates from geographically widespread locations, and an assay comprising 16 such loci (MLVA-16) was proposed. This scheme includes eight minisatellite loci (panel 1) and eight microsatellites (panel 2, which is subdivided into panels 2A and 2B). The utility of MLVA-16 for the subtyping of human Brucella isolates from geographically restricted regions needs to be further evaluated, and genotyping databases with worldwide coverage must be progressively established. In the present study, MLVA-16 was applied to the typing of 42 human Brucella isolates obtained from 41 patients recovered from 2002 to 2006 at a tertiary-care center in Lebanon. All isolates were identified as Brucella melitensis by MLVA-16 and were found to be closely related to B. melitensis isolates from neighboring countries in the Middle East when their genotypes were queried against those in the web-based Brucella2007 MLVA database (http://mlva.u-psud.fr/). Panel 2B, which comprised the most variable loci, displayed a very high discriminatory power, while panels 1 and 2A showed limited diversity. The most frequent genotype comprised seven isolates obtained over 7 weeks in 2002, demonstrating an outbreak from a common source. Two isolates obtained from one patient 5 months apart comprised another genotype, indicating relapsing disease. These findings confirm that MLVA-16 has a good discriminatory power for species determination, typing of B. melitensis isolates, and inferring their geographical origin. Abbreviated panel 2B could be used as a short-term epidemiological tool in a small region of endemicity