Seventeen multiple-antibiotic-resistant nonpathogenic Escherichia coli strains of human, animal, and food origins showed a wide variety of antibiotic resistance genes, many of them carried by class 1 and class 2 integrons. Amino acid changes in MarR and mutations in marO were identified for 15 and 14 E. coli strains, respectively.

DNA fingerprinting is a technique for comparing DNA patterns that has applications in a wide variety of contexts. Several commercial and freely-available tools can be used to analyze DNA fingerprint gel images; however, commercial tools are expensive and usually difficult to use; and, free tools support the basic functionality for DNA fingerprint analysis, but lack some instrumental features to obtain accurate results. In this paper, we present GelJ, a feather-weight, user-friendly, platform-independent, open-source and free tool for analyzing DNA fingerprint gel images. Some of the outstanding features of GelJ are mechanisms for accurate lane- and band-detection, several options for computing migration models, a number of band- and curve-based similarity methods, different techniques for generating dendrograms, comparison of banding patterns from different experiments, and database support. GelJ is an easy to use tool for analyzing DNA fingerprint gel images. It combines the best characteristics of both free and commercial tools: GelJ is light and simple to use (as free programs), but it also includes the necessary features to obtain precise results (as commercial programs). In addition, GelJ incorporates new functionality that is not supported by any other tool.

TEM-, SHV-, and OXA-type β-lactamases were studied by PCR with 124 ampicillin-resistant (AMP^r)Escherichia coliisolates recovered from foods of animal origin (n= 20) and feces of humans (n= 49) and healthy animals (n= 55). PCR showed that 103 isolates were positive for TEM and negative for SHV and OXA. ThreeE. coliisolates showed a positive reaction for OXA, and one showed a positive reaction for SHV. The remaining 17E. coliisolates were negative for the three enzymes by PCR. Fifty-seven of the 103bla_TEMamplicons were sequenced. Different molecular variants ofbla_TEM-1were found in 52 isolates:bla_TEM-1a(n= 9),bla_TEM-1b(n= 36),bla_TEM-1c(n= 6), andbla_TEM-1f(n= 1). Four inhibitor-resistant TEM (IRT) β-lactamase-encoding genes were also detected:bla_TEM-30c(IRT-2),bla_TEM-34b(IRT-6),bla_TEM-40b(IRT-11), andbla_TEM-51a(IRT-15). A newbla_TEMgene, namedbla_TEM-95b, which showed a mutation in amino acid 145 (P→A) was detected. It was found in a food isolate of chicken origin (AMP^r, amoxicillin-clavulanic acid susceptible). The promoter region in 24bla_TEMamplicons was analyzed, and the weakP3promoter was found in 23 of them (bla_TEM-1in 20 amplicons andbla_TEM-51a,bla_TEM-30c, andbla_TEM-95bin 1 amplicon each). The strongPa/Pbpromoter was found only in thebla_TEM-34bgene. No extended-spectrum β-lactamases were detected. Mutations at position −42 or −32 in theampCgene promoter were demonstrated in 4 of 10E. coliisolates for which the cefoxitin MIC was ≥16 μg/ml. Different variants ofbla_TEM-1and IRTbla_TEMgenes were found among the AMP^rE. coliisolates from foods and the feces of humans and healthy animals, and a new gene,bla_TEM-95b(P3), was detected.

Colonization by Campylobacter strains was investigated in human, broiler, and pig fecal samples from 1997- 1998, as well as in foods of animal origin, and antibiotic susceptibility testing was carried out for these strains. Campylobacter strains were isolated in the foods of animal origin (55 of 101 samples; 54.4%), intestinal samples from broilers (85 of 105; 81%), and pigs (40 of 45; 88.9%). A total of 641 Campylobacter strains were isolated from 8,636 human fecal samples of clinical origin (7.4%). Campylobacter jejuni was the most frequently isolated species from broilers (81%) and humans (84%), and Campylobacter coli was most frequently isolated from pigs (100%). An extremely high frequency of ciprofloxacin resistance was detected among Campylobacter strains, particularly those isolated from broilers and pigs (99%), with a slightly lower result for humans (72%); cross-resistance with nalidixic acid was almost always observed. A higher frequency of resistance to erythromycin (81.1%), ampicillin (65.7%), gentamicin (22.2%), and amikacin (21.6%) was detected in C. coli strains isolated from pigs compared to those isolated from humans (34.5, 29.3, 8.6, and 0%, respectively). A low frequency of erythromycin resistance was found in C. jejuni or C. coli isolated from broilers. A greater resistance to ampicillin and gentamicin (47.4 and 11.9%, respectively) was detected in C. jejuni isolated from broilers than in human strains (38 and 0.4%, respectively). β-Lactamase production was found in 81% of the Campylobacter strains tested, although 44% of them were characterized as ampicillin susceptible. The increasing rates of Campylobacter resistance make advisable a more conservative policy for the use of antibiotics in farm animals.

Seventy-eight isolates of different Enterococcus species ( E. faecalis , n = 27; E. faecium , n = 23; E. durans , n = 8; E. avium , n = 6; E. hirae , n = 9; E. gallinarum , n = 3; and E. casseliflavus , n = 2) with a variety of erythromycin resistance phenotypes were examined for the presence of macrolide resistance genes ( ermA , ermB , ermC , ermTR , mefA/E , and msrA ). Positive PCR amplifications of ermB were obtained for 39 of 40 highly erythromycin-resistant Enterococcus isolates (MICs, >128 μg/ml) of different species; the remaining highly resistant E. faecium isolate was positive for PCR amplification of ermA but was negative for PCR amplification of the ermB and ermC genes. For all enterococcal strains for which erythromycin MICs were ≤32 μg/ml PCRs were negative for erm methylase genes. For all E. faecium isolates PCR amplified products of the expected size of 400 bp were obtained when msrA primers were used, with the results being independent of the erythromycin resistance phenotype. All the other enterococcal species gave negative results by msrA PCRs. Sequencing of the msrA PCR products from either erythromycin-susceptible, low-level-resistant, or highly resistant E. faecium strains showed that the amplicons did not correspond to the msrA gene described for Staphylococcus epidermidis but corresponded to a new putative efflux determinant, which showed 62% identity with the msrA gene at the DNA level and 72% similarity at the amino acid level. This new gene was named msrC .

A total of 76 Lactobacillus plantarum and Oenococcus oeni wild strains were recovered from traditionally elaborated Spanish red wines and were investigated with respect to their response to acid pH, lyophilisation, temperature and ethanol concentrations which are normally lethal to lactic acid bacteria. Both L. plantarum and O. oeni strains were able to grow at pH 3.2, were highly resistant to lyophilisation treatment and proliferated in the presence of up to 13% ethanol at 18 degrees C. Therefore, it is shown that both species are highly tolerant to stress conditions and that similarly to O. oeni strains, L. plantarum strains are of interest in beverage biotechnology.