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The activities of a short therapeutic regimen with azithromycin and the classic treatment doxycycline with streptomycin were compared and evaluated in mice infected with Brucella melitensis. In a chronic model, starting therapy 31 days after challenge, azithromycin (10 days, 50 mg/kg/day) significantly reduced the infection (2.9 logs, day 48 post-infection). The effectiveness of doxycycline (21 days, 50 mg/kg/12 hourly) was greater than azithromycin (4.1 logs of reduction, day 48 post-infection), and when doxycycline was administered for a period of 45 days, all the animals were bacteriologically cured from day 78. The combination with streptomycin (14 days, 10 mg/kg/day) did not improve the effect of any of the regimens. In an acute model infection, treatments with doxycycline or doxycycline-streptomycin, for a period of 3 days, starting 1 day after lethal challenge, were able to protect all the mice. In contrast, only 50% of the mice treated with azithromycin survived the challenge. In conclusion, although a short oral treatment with azithromycin was able to reduce the infection significantly, it was not able to cure the animals as effectively as the classic regimen with doxycycline administered for a longer period of time. [ABSTRACT FROM AUTHOR]

The presence of Listeria spp. was investigated in a total of 3685 food samples obtained from different industries and markets of Northern Spain in the last 4 years. The samples analyzed include fresh raw products (meat, milk and poultry) and treated products (cooked and cured meats, frozen vegetables and smoked salmon). Occurrence of Listeria spp. varied from 8.1% in soft cheese to 76.3% in raw poultry samples. The highest incidence of L. monocytogenes also occurred in raw poultry (36.1% positive samples). Despite this high incidence of contamination, these kinds of products carry a low risk of listeriosis transmission because of the heat treatment prior to consumption. On the other hand, the ready-to-eat products (RTE) tested in this study showed incidences that could pose serious health problems, taking into account that the storage conditions may allow for rapid growth of the pathogen. It was also found that up to 75.5% of the L. monocytogenes strains isolated in this study belonged to serogroup 1, mainly serotype 1/2a, while the clinical cases observed in Navarra in the same period of time belonged mainly to serotype 4b/4bx.

The incidence of Listeria monocytogenes in a vegetable processing plant was investigated over a 23-month period. Frozen ready-to-eat vegetable samples, well as the plant environment, were sampled. The molecular subtyping techniques, Random Amplified Polymorphic DNA (RAPD) and Restriction Endonuclease Analyses (REA), were performed to help investigate the origin and routes of Listeria dissemination. The low and sporadic incidence of L. monocytogenes made it impossible to establish an epidemiological sequence in the processing plant, though a case of cross-contamination between tomato and ratatouille was detected. Listeria innocua subtyping, however, allowed us to determine the prevalence of several strains in vegetables, and their presence on machinery samples suggested the possibility of cross-contamination during processing. The low incidence of L. monocytogenes indicated that the risk of listeriosis transmission by vegetable consumption is low. On the other hand, the isolation of the same strain of L. innocua in several surveys pointed out the risk of colonisation on surfaces and machinery. The persistence of Listeria spp. is a cause for concern as can lead to future contamination of vegetables processed in the plant and to a possible increased risk for health. Therefore, periodic controls for the presence of Listeria spp. and a further review of the cleaning and disinfection procedures used in frozen vegetable plants are recommended.

Drugs inside a conventional galenic form are distributed between specific biological targets and other anatomical tissues. With the aim to obtain a more rational and a better therapeutic, one of the most promising possibilities by using the concept of vectorization: association of an active principle to an appropriate vector with the object to increase its action efficiency and efficacy. By this means, they do not just increase the affinity of the drug to the target but also active principle gets protected from a potentially hostile environment (hydrolytic enzymes, acid pH, etc.). The success in the extension of the applications of the vectorización depends more and more of an appropriate design, for what the fundamental objective of this revision will be the one of presenting the general characteristics and some of the current applications in these new galenic forms.

The presence of Listeria spp. was investigated in 369 samples of cooked meat products and 52 of smoked salmon. Incidences of 17.6% for cooked meat and 38.5% for smoked salmon samples were found. All Listeria monocytogenes isolates (34 from meat products and 16 from smoked salmon) were typed serologically and by random amplified polymorphic DNA (RAPD) typing using primers HLWL74 (5'-ACGTATCTGC-3'), HLWL85 (5'-ACAACTGCTC-3'), and OMP-01 (5'-GTI'GGTGGCT-3'). Strains from cooked meat products were characterized and compared in relation to their origin. The detection of identical strains in products of different type and brand packed on the same date suggested cross-contamination, probably during the slicing process. All L monocytogenes isolates from smoked salmon were indistinguishable by serotyping and RAPD, suggesting that this strain was highly disseminated and adapted to the treatment used for the preservation of this food. RAPD subtypes were analyzed using GelCompar version 4.1 software and the unweighted pair method using arithmetic averages, and six groups with at least 78% similarity were established. Serotyping and RAPD results were in concordance, although RAPD showed a higher discriminatory power with L. monocytogenes isolates from meat products. RAPD is an easy method that could be useful to detect cross-contamination occurring during postprocessing manipulations.

Liposomes of the stable multilamellar type, which previously demonstrated great efficiency in antibiotic transport [Vitas et al: Antimicrob Agents Chemother 1996;40:146-151] were used in this study as carriers of gentamicin for treatment of mice lethally infected with Brucella abortus. Treatment with gentamicin in positively charged liposomes produced a protective effect when it was administered 1 day after lethal challenge (70% of protection). On the other hand, the use of free gentamicin or in liposomes with a negative net charge did not produce a protective effect. Moreover, the results reported here also indicated that cationic liposomes themselves had a therapeutic effect on the course of the infection (up to 50% of protection). In conclusion, we observed that cationic liposomal encapsulation of gentamicin resulted in an enhancement of the therapeutic activity of free gentamicin in this mouse model of acute infection.