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Indigenous Australians experience a significant health burden from chronic hepatitis B infection; however, the strain of hepatitis B virus (HBV) found among Indigenous Australians has not been well characterized. Blood samples were collected from 65 Indigenous Australians with chronic HBV infection from across the Top End of Australia's Northern Territory. Phylogenetic analysis of HBV from these samples revealed that 100% of the isolates were genotype C, sub-genotype C4, expressing the serotype ayw3. This strain is a divergent group within the HBV/C genotype, and has only been described in Indigenous Australians. Evidence of recombination was suggested by discordant phylogenetic clustering of the C4 sequences when comparing the full genome to the surface region and confirmed by recombination analysis which showed the surface gene region to be most closely related to genotype J, while the remaining regions of the genome were most similar to genotype C sequences. Mutational analysis revealed the presence of multiple mutations that have been linked with more rapid liver disease progression and an increased risk of hepatocellular carcinoma. These mutations were detected in the majority of sequences examined. Variants associated with vaccine failure were detected as the predominant viral quasi-species in 3/35 samples. In summary, the HBV C4 variant found in this population has a high potential to cause advanced liver disease and to escape vaccination programs. Further in vitro functional and natural history studies are warranted in order to determine the clinical and public health consequences of infection with the HBV C4 variant in these communities.

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Hepatitis delta virus (HDV) is encapsidated by the envelope proteins of hepatitis B virus (HBV). The major HBV lamivudine (LMV)-resistant mutations in the polymerase gene within the reverse transcriptase (rt) region at rtM204V or rtM204I are associated with changes in the overlapping envelope gene products, in particular, the gene encoding small envelope protein (s) at sI195M or sW196L/S/Stop. We have demonstrated that the LMV resistance mutations corresponding to sW196L/S inhibited secretion of HDV particles, while changes corresponding to sI195M did not affect secretion. Differential efficiencies of HBsAg proteins expressed by LMV-resistant HBV to support HDV secretion may have consequences for clinical prognosis as coinfected patients are treated with antiviral agents.

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Microbiological developments during industrial meat fermentations (salami), made with and without commercial starter cultures, were followed at two factories in Germany and Italy. In the German product microbial growth was evident only for the first 48 h, followed by a gradual decline in numbers of most micro-organisms. The pH fell from 5.8 to 4.8 in the 28 d required for production. In Italy a similar situation was seen, except that a second period of bacterial growth began around 15 d, coincident with the appearance of intentional surface mould growth which reversed the pH fall, the final pH being 6.2. The German starter culture was a mixture of Lactobacillus plantarum and Staphylococcus carnosus, whereas in Italy only Staph. carnosus was used. The strain of Lact. plantarum used did not grow in the German product whereas the Staph. carnosus grew well in both products to form a substantial proportion of the final microflora.

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Some industrial preparations from milk, such as yogurt, contain bifidobacteria as an additional probiotic element. The acidic environment of these products affects the viability of the bifidobacteria. The survival in acidic environment of one-hundred and ten bifidobacterial strains from human habitat was tested.

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The aim of this work is to analyse the capacity of several formulas of stimulating the growth of bifidobacteria (Bif.), as these formulas may induced an approach to the intestinal microbiological peculiarities of breast-fed infants. This capacity has been compared with the fecal pH (fig. 2) in the various groups of artificially-fed infants and with the buffering capacity (fig. 1 a. 3) of the different milks. Six group of infants fed the following milks feed were examined: one breast-fed and five artificially-fed (table 1). Fecal specimens were examined at the 4th, 11th and 18th day of life. It is pointed out that different formulas have different capacity of stimulating the growth of Bif., both in the percentage of colonized subjects and in the developed amount of Bif. (tab. 2). It is exhibited a mutual relation between this capacity of a food and the fecal pH (fig. 3) in newborn infants fed on this food. On the contrary it is not easy to find a clear relation between the capacity of growth of Bif. and the buffering properties of a milk: two of the tested milks have nearly the same buffering capacity but allow completely different colonisation (fig. 1 a. 3). It is suggested that if this mutual relation was real, we must think of "how" this buffer capacity is realized and not of its absolute value. Although several Authors proved that there is a "in vitro" antagonism between Bif. and E. coli, it is not confirmed this statement "in vivo" (fig. 2 a. 3).(ABSTRACT TRUNCATED AT 250 WORDS)

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Fourteen strains of Bifidobacterium longum were tested for phage production with UV and mitomycin C as inducing agents. Only four strains released phage-like particles; of these four strains, two harbour plasmids, while two are apparently plasmid free. The induced phages have heads of dimensions ranging from 49 to 56 nm and tails from 76 to 268 nm long. No correlation is evident between any of the large variety of plasmids of B. longum and induced phages.

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Twenty-nine strains of Lactobacillus bulgaricus and 15 strains of Streptococcus thermophilus were tested for resistance to 35 antimicrobial agents by using commercially available sensitivity disks. Approximately 35% of the isolates had uncharacteristic resistance patterns.

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The qualitative and quantitative abilities of phages of 13 strains of thermophilic lactic bacteria (lactobacilli and streptococci) to produce plaques on six different media were studied. The influence of the addition of calcium on the one hand, and of incubation conditions (aero-anaerobiosis), on the other hand, was also examined. For the phages of lactobacilli, the best results were obtained with the medium of de Man, Rogosa, and Sharpe (1960), whereas for the phages of streptococci the medium of Hogg and Jago (1970) appeared to be the best. Calcium and incubation conditions play a role which is variable in importance, but rarely negligible.

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Electron microscopic examination of samples of Swiss wine, collected during the malolactic fermentation, revealed the presence of bacteriophages of three different morphological types. It is interesting to note that these phages have been found in a product whose pH is lower than 3.5.

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