No abstract

Colistin resistance genes mcr-3 and mcr-1 have been detected in an Escherichia coli isolate from cattle faeces in a Spanish slaughterhouse in 2015. The sequences of both genes hybridised to same plasmid band of ca 250 kb, although colistin resistance was non-mobilisable. The isolate was producing extended-spectrum beta-lactamases and belonged to serotype O9:H10 and sequence type ST533. Here we report an mcr-3 gene detected in Europe following earlier reports from Asia and the United States.

A study was made of the staphylococcal population on the skin and on the nasal mucosa and in the milk of 133 healthy goats. Of a total of 346 strains isolated and characterised as belonging to the genus Staphylococcus, 74 (21.4 %) were coagulase-positive (68 S. aureus and 6 S. hyicus), and 272 (78.6 %) coagulase-negative. The novobiocin-sensitive species S. huemolyticus (23.5 YO), S. wurneri (16.5 '%), S. epidermidis (1 1.8 YO), S. chromogenes (8.5 Yo), S. caprue (6.6 Yo) and S. hyicus (2.6 YO), and the novobiocin-resistant species S. xylosus (8.5 %), S. sczurz (7.4 %), S. saprophyticus (4.8 %), S. cohnii (2.2 "YO) , S. lentus (1.1 I % ) , S. equorum (1.1 Yo) and S. kloosii (1.1 "/") were identified. Twelve (4.4 %) of coagulase-negative strains remained unidentified. Strains isolated in the skin of the udder and teats of the 133 goats were mainly novobiocin-sensitive coagulase-negative staphylococci, the most prevalent species being S. huemolyticus, S. wurneri and S. epidermidis. Staphylococci indicative of subclinical infection were determined in the milk of 47 (35.3 %) of the 133 goats sampled. U.S.Samples were taken from 133 female Verata goats from 11 different extensive flocks in the province of Ciceres (Spain). All animals were in lactation, and were clinically healthy. SamplesSamples were collected from the nasal mucosa and the skin of the axillary fold, the udder surface and the teat, on sterile moist swabs. Milk (50 mi) was collected in sterilized containers, after washing and disinfecting the teats. All samples were rapidly transferred to the laboratory in an isothermic container at 4 "C. Mucosa and skin samples were streaked from the swabs onto sheep blood agar (5 %) (Oxoid). Milk samples (loo& were spread onto sheep blood agar (5%) (Oxoid) and Schleifer and Krimer's staphylococci selective medium (SCHLEIFER and KRAMER, 1980). Plates were incubated in aerobic conditions at 37°C for 24-72 hours. Colonies whose cell morphology resembled that of Gram-positive, catalase-positive cocci, were selected. O n e or two selected colonies were used to obtain purified cultures on Brain Heart Infusion agar (Difco). MicroorganismsA total of 359 strains of gram-positive, catalase-positive cocci were tested. Differentiation of staphylococci and minococci

The ability of 342 staphylococcal isolates from different anatomical sites in healthy goats to produce staphylococcal enterotoxins (SE) was investigated. SE were produced by 74.3% of the 70 coagulase-positive strains and by 22% of the coagulase-negative strains studied. Most enterotoxigenic strains were isolated from the skin of udders and teats and from milk. SEC was the SE type most frequently produced, either alone (67.9%) or in combination with others. Five coagulase-negative species not previously reported as SE producers were identified (Staphylococcus chromogenes, S. warneri, S. sciuri, S. saprophyticus, and S. lentus). SEA, SEB, and SEC were detected in the milk of 17 of the 133 healthy goats studied. These results suggest that the goat is an important reservoir of enterotoxigenic staphylococci, most of which produce SEC.

The main determinant for beta-lactamase expression in Bacteroides strains is the cfxA gene, in which IS614B integration upstream of the coding sequence represents a molecular marker for higher levels of enzyme activity.