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The aim of this study was to investigate the phenotypic and genotypic antibiotic resistance profiles of pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which were representative of areas that are possible sources of meat contamination. Mesophilic (85 isolates) and psychrotrophic (37 isolates) pseudomonads identified at the species level generally were resistant to sulfamethoxazole, erythromycin, amoxicillin, ampicillin, chloramphenicol, trimethoprim, rifampin, and ceftazidime (especially mesophiles), as well as colistin and tetracycline (especially psychrotrophes). However, they generally were sensitive to ciprofloxacin, gentamicin, imipenem, and kanamycin regardless of species identity. Worryingly, in the present study, we found multidrug resistance (MDR) to up to 13 antibiotics, which was related to intrinsic and acquired resistance mechanisms. Furthermore, a link between various antimicrobial resistance genes was shown for beta-lactams and tetracycline, trimethoprim, and sulfonamides. The distribution and resistome-based analysis of MDR pseudomonads in different slaughterhouse zones indicated that the main sources of the identical or related pseudomonad strains were the animals (feet and wool) and the slaughterhouse environment, being disseminated from the beginning, or entrance environment, to the environment of the finished meat products. Those facts must be taken into consideration to avoid cross-contamination with the subsequent flow of mobile resistance determinants throughout all slaughterhouse zones and then to humans and the environment by the application of adequate practices of hygiene and disinfection measures, including those for animal wool and feet and also the entrance environment.

Fermentation of capers (the fruits of Capparis sp.) was studied by molecular and culture-independent methods. A lactic acid fermentation occurred following immersion of caper berries in water, resulting in fast acidification and development of the organoleptic properties typical of this fermented food. A collection of 133 isolates obtained at different times of fermentation was reduced to 75 after randomly amplified polymorphic DNA (RAPD)-PCR analysis. Isolates were identified by PCR or 16S rRNA gene sequencing as Lactobacillus plantarum (37 isolates), Lactobacillus paraplantarum (1 isolate), Lactobacillus pentosus (5 isolates), Lactobacillus brevis (9 isolates), Lactobacillus fermentum (6 isolates), Pediococcus pentosaceus (14 isolates), Pediococcus acidilactici (1 isolate), and Enterococcus faecium (2 isolates). Cluster analysis of RAPD-PCR patterns revealed a high degree of diversity among lactobacilli (with four major groups and five subgroups), while pediococci clustered in two closely related groups. A culture-independent analysis of fermentation samples by temporal temperature gradient electrophoresis (TTGE) also indicated that L. plantarum is the predominant species in this fermentation, in agreement with culture-dependent results. The distribution of L. brevis and L. fermentum in samples was also determined by TTGE, but identification of Pediococcus at the species level was not possible. TTGE also allowed a more precise estimation of the distribution of E. faecium , and the detection of Enterococcus casseliflavus (which was not revealed by the culture-dependent analysis). Results from this study indicate that complementary data from molecular and culture-dependent analysis provide a more accurate determination of the microbial community dynamics during caper fermentation.

The structural gene of the enterococcal peptide antibiotic AS-48 (as-48) has been identified and cloned by using two degenerate 17-mer DNA oligonucleotides on the basis of the amino acid sequences of two peptides obtained by digestion of the antibiotic with Glu-C endoproteinase. That as-48 gene codes for a 105-amino-acid prepeptide, giving rise to a 70-amino-acid mature protein. Comparative analysis demonstrated that the 16-amino-acid sequence of one of the AS-48 Glu-C peptides, designated V8-5, was composed of a 12-amino-acid sequence corresponding to the C-terminal end sequence (from isoleucine +59 to tryptophan +70 [I+59 to W+70]) of the prepeptide and terminated in four residues forming the N terminus (M+1 to E+4) of a putative AS-48 propeptide. These data, combined with the characteristics of the gene sequence, strongly suggested that the antibiotic peptide was a 70-residue cyclic molecule. We propose that the AS-48 translated primary product is very likely submitted to a posttranslational modification during secretion (i) by an atypical or a typical signal peptidase that cleaves off a 35-residue or shorter signal peptide, respectively, from the prepeptide molecule and (ii) by the linkage of the methionine residue (M+1) to the C-terminal tryptophan residue (W+70) to obtain the cyclic peptide (a tail-head linkage).

Amoebicin m4-A from Bacillus licheniformis M-4 exerts a bactericidal and bacteriolytic action on Bacillus megaterium GR10. Protein, DNA, and RNA synthesis are inhibited, and the membrane electrical potential of this bacterium is depleted by amoebicin. Synthesis of DNA and RNA by Naegleria fowleri HB-1 is also inhibited. Liposomes constructed from L-alpha-phosphatidylcholine become permeable to ions, low-molecular-weight solutes, and high-molecular-weight polymers after treatment with amoebicin.

The strain Bacillus licheniformis D-13 produces three hydrophobic peptides (amoebicins d13-A, d13-B, and d13-C) that elicit antiamoebic activity against human-pathogenic and nonpathogenic species of Naegleria and have a broad spectrum of antibacterial activity. The three amoebicins have the same amino acid composition (three Asp, two Glu, two Val, and nine Leu residues) and molecular weight (1,870). Amoebicin d13-B causes lysis of amoebae through disorganization of the cell membrane. It also induces permeability to 86Rb and membrane disruption in asolectin vesicles.

Bacillus licheniformis A12 produces two amoebolytic substances (amoebicins A12-A and A12-B) in liquid media during sporulation. Both substances have been purified and characterized. They are heat- and protease-resistant peptides containing aspartic acid, glutamic acid, serine, proline, and tyrosine in a molar ratio of 5:2:2:2:2. No fatty acids or carbohydrates have been detected. Their molecular weight is 1,430. Purified amoebicins A12-A and A12-B exhibit amoebolytic action against Naegleria fowleri. They also exhibit antibiotic action against yeasts (Saccharomyces heterogenicus and Cryptococcus neoformans) and several fungal species (Aspergillus niger, Microsporum canis, Mucor plumbeus, and Trychophyton mentagrophytes). Their antibacterial spectrum appears to be restricted to Bacillus megaterium, Corynebacterium glutamicum, and Sarcina sp.

Peptide AS-48 induces ion permeation, which is accompanied by the collapse of the cytoplasmic membrane potential, in sensitive bacteria. Active transport by cytoplasmic membrane vesicles is also impaired by AS-48. At low concentrations, this peptide also causes permeability of liposomes to low-molecular-weight compounds without a requirement for a membrane potential. Higher antibiotic concentrations induce severe disorganization, which is visualized under electron microscopy as aggregation and formation of multilamellar structures. Electrical measurements suggest that AS-48 can form channels in lipid bilayers.

Lactobacillus pentosus MP-10 was isolated from brines of naturally fermented Aloreña green table olives. MP-10 has potential probiotic traits, including inhibition of human pathogenic bacteria, survival at low pH (1.5), and bile salt tolerance (3%). Here, we report for the first time the annotated genome sequence of L. pentosus .

Weissella thailandensis fsh4-2 is a heterofermentative lactic acid bacterium isolated from the Korean fermented seafood condiment jeotkal. Here we report the draft genome sequence of W. thailandensis fsh4-2 (1,651 genes, 1,436 encoding known proteins, 183 encoding unknown proteins, 32 RNA genes), which consists of 50 large contigs of >100 bp.

The enterococcal peptide AS-48 exerts a concentration-dependent bactericidal effect on Enterococcus faecalis subsp. liquefaciens S-47; cell rescue by cardiolipin and trypsin can be effected only in the first few minutes after antibiotic addition. Gramicidin-exposed cells are protected from killing by AS-48. Long-term and pulse incorporation of radiolabeled substrates into trichloroacetic acid-precipitable material, O2 consumption, and the ability to maintain intracellular potassium levels are impaired shortly after addition of AS-48.