CTX-M enzymes, mainly CTX-M-14 and CTX-M-15, have emerged as the most prevalent extended-spectrum β-lactamase (ESBL) type produced by Escherichia coli in Spain, with successful dissemination of clonal group O25b:H4-B2-ST131 producing CTX-M-15 within the hospital and community settings. However, until now CTX-M-14-producing E. coli in Spain had been shown to belong to a wide variety of serotypes with no predominance of a certain clonal group. In the present study, 654 E. coli strains positive for ESBL production obtained between 2005 and 2008 from inpatients and outpatients of four hospitals in Galicia, northwest Spain, were analysed. The strains were characterised with regard to ESBL enzymes, serotype, virulence genes, phylogenetic group, multilocus sequence type, and pulsed-field gel electrophoresis of XbaI-digested DNA. As a result, the emergence of certain clonal groups of extraintestinal pathogenic E. coli producing CTX-M-14 has been detected in this geographic area, including O1:HNM-D-ST59, O15:H1-D-ST393/ST1394, O20:H34/HNM-D-ST354, O25b:H4-B2-ST131 and ONT:H21,42-B1-ST101. These five clonal groups showed a high virulence potential as they harboured more than eight virulence factors, which could explain their successful dissemination.

The performance of an ELISA for detection of total antibodies to Brucella spp. was compared with that of the Rose Bengal, standard agglutination and Coombs test in the diagnosis of brucellosis. Sera tested were from 208 patients from whom Brucella melitensis had been isolated, 177 patients with significant results in at least two conventional tests, and 107 patients with fever from whom no Brucella spp. had been isolated and in whom all conventional tests were negative. ELISA was the most sensitive test (97%), showing greater specificity (96%) and good predictive positive and negative values (98% and 94% respectively). ELISA was the only positive test in 6% of patients in whom brucellosis had been confirmed by culture.

Diarrheal stool specimens were inoculated into the following media: alkaline peptone water (APW), Bruce-Zochowsky medium (BZ), Campylobacter enrichment broth (CEB), Cantpy-thio broth (CT), and Skirrow blood agar (SK) plate. All media were incubated at 42°C in microaerophilic conditions for 24 h. Afterwards, a new SK plate was inoculated from every liquid medium. Campylobacterjejuni was isolated from 43 of the 259 specimens when CT was used, from 45 when APW was used, from 46 when BZ was used, and from 46 when CEB was used; these totals include specimens that grew after enrichment only, on SK plates only, and both after enrichment and on SK plates. No significant differences were found between the isolates obtained with and without enrichment procedures.

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Diarrheal stools from 263 patients were inoculated on seven selective media: Butzler selective medium, Blaser medium, Skirrow blood agar, Preston campylobacter selective medium, Preston campylobacter blood-free medium, Butzler Virion medium, and modified Preston medium (with amphotericin B [2 mg/liter]). A similar number of Campylobacter jejuni strains were isolated from all the media studied; nevertheless, the presence of competing fecal flora (FF) made the detection of suspect colonies difficult. Preston campylobacter blood-free medium with cefoperazone yielded the greatest number of C. jejuni isolations, and contaminating FF grew in only 9% of the plates showing C. jejuni growth; all the other media allowed the abundant growth of other FF, regardless of whether C. jejuni was isolated from them or not.

Six hundred and thirteen fresh diarrhoeal faeces were inoculated on Skirrow blood agar (SK), on Preston blood free agar (PBF), and in Campy-thioglycolate broth (CT). After 24 h of storage at 4 degrees C, specimens were again inoculated on SK and PBF, and in Campylobacter enrichment broth (CEB). CT tubes were placed overnight at 4 degrees C. Plates and CEB tubes were incubated at 43 degrees C in microaerophilic conditions. A total of 68 specimens was positive for campylobacter on direct plating. Sixty-four of them were also recovered after subculturing from CT, and only 51 from CEB. Delayed inoculation of plates after storage of samples at 4 degrees C yielded 57 isolates. The storage of faeces at 4 degrees C for 24 h significantly reduces the number of campylobacter isolates. When samples are not plated immediately we recommend inoculating a CT tube maintained at 4 degrees C overnight as a holding medium.

A total of 800 colonies suggestive of Salmonella, Shigella, or Yersinia species isolated on stool differential agar media were inoculated onto both conventional biochemical test media (triple sugar iron agar, urea agar, and phenylalanine agar) and Entero Pathogen Screen cards of the AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.). Based on the conventional tests, the AutoMicrobic system method yielded the following results: 587 true-negatives, 185 true-positives, 2 false-negatives, and 26 false-positives (sensitivity, 99%; specificity, 96%). Both true-positive and true-negative results were achieved considerably earlier than false results (P < 0.001). The Entero Pathogen Screen card method is a fast, easy, and sensitive method for screening for Salmonella, Shigella, or Yersinia species. The impossibility of screening for oxidase-positive pathogens is a minor disadvantage of this method.

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