Molecular epidemiological and antibiotic susceptibility characterization of Brucella isolates from humans in Sicily, Italy.
Brucellosis is a serious problem in Sicily. Brucella melitensis was identified as the species most frequently isolated in humans in Italy. No data, however, are available about the molecular epidemiological characterization of Brucella isolates from humans. We have conducted this study to molecularly characterize clinical isolates of Brucella spp. and to evaluate their antimicrobial susceptibilities. Twenty Brucella isolates were studied. Differential growth characteristics and DNA polymorphisms such as the restriction patterns of the PCR-amplified omp2a and omp2b genes, rpoB nucleotide sequencing, and multiple-locus variable-number tandem repeat analysis of 16 loci (MLVA-16) were used to characterize the strains. In vitro antibiotic susceptibility was determined by the E-test method on two different agar media, and the results were compared. All isolates were identified as B. melitensis biovar 3. rpoB nucleotide sequence analysis allowed the identification of two different genotypes of B. melitensis biovar 3. On the other hand, the MLVA-16 typing assay recognized 17 distinct genotypes. All isolates were sensitive to all tested antibiotics (rifampin, doxycycline, ciprofloxacin, ceftriaxone, and trimethoprim-sulfamethoxazole), and the Mueller-Hinton agar plate is recommended for antibiotic susceptibility testing by the E-test method. Our findings identify B. melitensis biovar 3 as the etiological agent isolated in Sicily and encourage the use of both molecular methods, and in particular of the MLVA-16 assay, in epidemiological trace-back analysis. This study represents the first epidemiological data from molecular typing of Brucella strains circulating in Italy and, in particular, in eastern Sicily.
Marianelli
Cinzia
C
Dipartimento di Sanità Alimentare ed Animale, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. cinzia.marianelli@iss.it
Graziani
Caterina
C
Santangelo
Carmela
C
Xibilia
Maria Teresa
MT
Imbriani
Alida
A
Amato
Rosa
R
Neri
Domenico
D
Cuccia
Mario
M
Rinnone
Sebastiano
S
Di Marco
Vincenzo
V
Ciuchini
Franco
F
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D017347:Brucella melitensis / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D002006:Brucellosis / Q000453:epidemiology* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D017720:Molecular Epidemiology; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D018272:Porins / Q000235:genetics; D017422:Sequence Analysis, DNA; D012802:Sicily / Q000453:epidemiology; D020080:Tandem Repeat Sequences / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C096735:Omp2a protein, Brucella; C096736:Omp2b protein, Brucella; D018272:Porins; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit