[Molecular biological and phenotypical characterization of human isolates of Salmonella enterica serovar Paratyphi B dT+ or Salmonella java].
OBJECTIVE
Salmonella Paratyphi B dT+ (or Salmonella Java) is an emerging public health problem. The study objective was to characterize phenotypically and genotypically 13 human isolates from sporadic cases of infection.


METHODS
Phenotypic characteristics of 13 human isolates were determined by phage typing, disk diffusion method for testing antimicrobial susceptibility to 11 antibiotics and screening for selected virulence markers, i.e bacterial adherence to xylene, motility and biofilm formation. Genotypic characteristics of the study isolates were determined by PCR with primers for the detection of class 1 integrons, plasmid profile analysis and PFGE for the study of genetic diversity.


RESULTS
The study isolates were classified into different phage types, with 3aI or 3aI variant being the most common (61.5%). All study isolates were resistant to streptomycin and sulfisoxazole, two of them were multiresistant (to streptomycin, sulfisoxazole, ampicillin and nalidixic acid). The study isolates showed low hydrophobicity, except for one isolate (2/08), and 5 isolates exhibited motility of > or = 50 mm. High biofilm formation was detected in 5 isolates. Class 1 integrons were not detected in any isolate and plasmid profile analysis revealed the presence of a 90-kb plasmid in 8 isolates. XbaI PFGE analysis differentiated the isolates into 6 pulsotypes (X1, X2, X2a, X3, X4,X5).


CONCLUSIONS
Although the study set of S. Paratyphi B dT+ (S. Java) was small, the increasing emergence of this serovar in the human population in Slovakia is noteworthy. The results of gene analysis in PFGE suggest clonal diversity as well as a clonal link between strains of the predominant phage type. In view of possible increase in antimicrobial resistance and the spread of certain clones, continuous surveillance of strains of S. Paratyphi B dT+ is needed.
Oddelenie mikrobiológie, NRC pre fagotypizáciu salmonel, Slovenská zdravotnícka univerzita, Bratislava, Slovenská republika. lubica.majtanova@szu.sk
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D001434:Bacteriophage Typing; D005759:Gastroenteritis / Q000382:microbiology; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D012484:Salmonella paratyphi B / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology