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.

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.