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Introduction: Azithromycin represents an alternative option to treat bacterial diarrhea when the antibiotic therapy is indicated. Little is known regarding the susceptibility to azithromycin in enteropathogens in Spain., Methods: The MICs of azithromycin were determined by E-test against Salmonella non-typhi (SNT), Shigella and Yersinia isolates collected over the last three years (2010-2012). In addition, the susceptibility to other antibiotics usually used to treat gastrointestinal diseases was determined in these isolates by using a microdilution method., Results: A total of 139 strains of SNT, Shigella and Yersinia were studied. All of them, except one strain, had a MIC≤16mg/L of azithromycin. In the adult population, 14.7% and 40.6% of SNT and Shigella isolates, respectively, were resistant to at least 2 of following antibiotics: amoxicillin, trimethoprim-sulfamethoxazole and ciprofloxacin. In the pediatric population, 10% of SNT clinical isolates and 28.6% (2/7) of Shigella isolates were resistant to amoxicillin and trimethoprim-sulfamethoxazole., Conclusions: In our experience, azithromycin would be a useful antibiotic alternative to treat bacterial diarrhea., (Copyright © 2013 Elsevier España, S.L. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)

Yersinia enterocolitica is a heterogeneous group of strains, which are classified into 6 biogroups, and into more than 57 O serogroups. However, the human pathogenic strains most frequently isolated worldwide belong to serogroups O:3, O:5,27, O:8 and O:9. The major route of Y. enterocolitica infection is through contaminated foods or water. The primary pathogenic event is colonization of the intestinal tract where most of the pathologic effects and clinical manifestations occur. Temperature and calcium concentration regulate expression of virulence factors that guide the invading yersiniae and allow them to survive and disseminate. Gastrointestinal infections are usually self-limiting and do not merit antimicrobial therapy. Nonetheless, fluoroquinolones or third generation cephalosporins, the best therapeutic options, are warranted to treat enterocolitis in compromised hosts and in patients with septicemia or invasive infection, in which the mortality can be as high as 50%. A review of the pathogenesis, virulence and antimicrobial resistance is carried out., (Copyright © 2011 Elsevier España, S.L. All rights reserved.)

Background: Yersinia enterocolitica is an important pathogen in temperate climates. The heterogeneity of the microorganisms covered by this denomination has a made grouping and identification schemes necessary., Methods: A series of 150 different, consecutive isolates from patients with diarrheic syndrome living in an urban area with a population of approximately 500,000 inhabitants, were studied in order to evaluate their biochemical, antigenic and sensitivity characteristics., Results: There was a high degree of uniformity among the strains isolated, 144 (96%) of which were identified as Yersinia enterocolitica sensu stricto, biotype 4, serotype 0:3. These strains presented, almost invariably, the same susceptibility pattern, being sensitive to amoxicillin/clavulanic acid, piperacillin, cefamandole, cefoxitin, gentamicin, amikacin, tetracycline and cotrimoxazole, and highly resistant to ampicillin, ticarcillin and cephazotin. In addition, 5 strains of Yersinia frederiksenii were isolated. The biochemical, epidemiological and sensitivity characteristics of these strains differed from those invariably found in the rest of the isolates., Conclusions: The data obtained in this study, shown a high degree of uniformity in the strains of Yersinia enterocolitica isolated in our area in recent years, with regard to both their biochemical characteristics and their sensitivity patterns. The isolations of the other biogroups may be regarded as extremely infrequent in the stool culture of patients with diarrhea treated in our hospitals.

Yersinia enterocolitica biotype 4, serotype 3 is a pathogenic bacteria for men. Its most likely reservoir are pigs. We have compared 48 Y. enterocolitica serotype 0:3 strains isolated from pig's tonsils samples as well as porcine-derived food with 301 Y. enterocolitica serotype 0:3 isolate from human stool's samples. All strains are positive for virulence tests. Yersinia enterocolitica serotype 0:3, biotype 4, phage-type VIII was nearly the only single pathogenic strain isolated from both origins in our county. Human and porcine strains showed a similar percentage of chloramphenicol and cotrimoxazol resistance. This pattern of resistance is not common among Y. enterocolitica strains isolated outside of our geographic area. The nearly identical patterns of human and porcine strains, as well as the high frequency of isolation from pig's tonsils (49.5%) and uncooked meal (12.9%) confirm the hypothesis that pigs are the most likely reservoir for human infections in our county.