This study provides understanding of farmed salmon GI bacterial communities and describes the relative impact of diet, environmental and farm factors.

M. KATOULI, L.MELIN, M. JENSEN-WAERN, P. WALLGREN AND R. MÖ L LB Y. 1999. The effect of a dietary supplementation of zinc oxide (ZnO) on the stability of the intestinal flora and on the composition of coliforms in weaned pigs was investigated. Faecal floras were characterized by their metabolic activities and fermentative capacity (FC) using the Phene Plate generalized microplate. Coliforms were characterized by conventional enumeration and by the Phene Plate-RS plates. The latter measured FC, phenotypic diversity, persistence of each coliform strain in piglets, and similarity among the coliform populations within groups. From weaning onwards, the control pigs (n 5) were fed a basal diet ad libitum, while experimental pigs (n 5) were given the same food supplemented with 2500 ppm ZnO. Metabolic fingerprinting of faecal floras indicated marked differences between the composition of floras of treated and control pigs during the first 2 weeks post-weaning. The FC of faecal flora in both groups decreased as pigs aged, but it was significantly (P ¾ 0·0001) lower in control pigs during the first 2 weeks post-weaning. Neither the number of coliforms, nor their FC-values, differed between the groups. However, during the first 2 weeks post-weaning, there was a significant increase in both variety (P 0·019) and diversity (P ¾ 0·001) of coliforms in control pigs compared with the ZnO treated group. Homogeneity between coliform populations of piglets was high during the suckling period, indicating the presence of many identical strains among piglets. This, however, decreased in control pigs during the first 2 weeks post-weaning. Several coliform strains that colonized the gut at the early stage of the pigs' life were found to be resident in animals of both groups. It is concluded that supplementation of ZnO to weaned pigs helped to maintain the stability of the intestinal microflora and the diversity of coliforms during the first 2 weeks post-weaning, but not later, and that ZnO supplementation to creep feed should be restricted to the first 2 weeks post-weaning in veterinary practice.

the 35 virulence genes tested from total DNA extract of the microbiota, only cdt and east1 were detected. Results indicate that temperature is the main driver of changes to the gut microbiota in farmed Tasmanian Atlantic salmon receiving these two diets.

No abstract

Staphylococcus aureus is a leading cause of hospital-acquired (HA) and community-acquired (CA) infections worldwide. Recently, S. aureus strains resistant to meticillin (MRSA) have become established within both communities. We isolated 314 isolates of MRSA from hospitalized patients in a referral hospital (HA isolates) and 268 isolates from its outpatient clinic (CA isolates) in Tehran, Iran, between February 2008 and December 2010. These isolates were tested for their susceptibility to 17 antibiotics and typed using the PhPlate system. The diversity in the structures of staphylococcal cassette chromosome mec (SCCmec) elements and ccr types was also detected using a multiplex-PCR assay and isolates were examined for the presence of different classes of prophages. Whilst all isolates were resistant to penicillin, the HA isolates were significantly more resistant to all other antibiotics tested than the CA isolates. Isolates carrying only SCCmec type III and ccr type 3 were dominant (91 %), but 20 % of the CA isolates belonging to less prevalent types carried only SCCmec types IVa, c and ccr type 2. These isolates also carried pvl genes and contained SGA prophage type. Our results indicate that whilst the dominant clonal groups of HA-and CA-MRSA belong to SCCmec type III and carry ccr type 3 genes, several distinct but less prevalent types of CA-MRSA carrying SCCmec type IVa, c and type 2 ccr are also found in Tehran. These strains carry pvl genes and the SGA prophage type, a characteristic that might be used as a marker for detection of CA-MRSA in this country.