After using of the streptothricin antibiotic nourseothricin in animal husbandry for growth promotion, plasmid-borne resistance to streptothricin could be observed in E. coli from nourseothricin fed pigs, from employees in pig farms and from their family members. Moreover, streptothricin resistance plasmids also occurred in E. coli of man without any contact to pig farms (gut flora and even urinary tract infections). However, these individuals live in villages and towns of the territory where nourseothricin was applied to pigs. Similar streptothricin resistance plasmids belonging to different incompatibility groups were found in both E. coli from pigs and E. coli from human beings. As no coselection of resistance to drugs indispensable for therapeutic use in man was observed, the application of nourseothricin in animal husbandry has not clinical implication for human medicine yet. Nevertheless, this problem remains under further investigation.
The majority of S. aureus strains isolated from beak-swabs and pathological processes in chicken shows coagulation of human plasma (not of bovine plasma), crystal violet-type A, hemolysinetype *4, formation of fibrinolysin, not formation of DXase and reactions with the experimental phage A1591. Because of the absence of DNase-formation and the reaction-specificity for phage A1591 we propose to designate these strains as host-specific variety gallinae of S. aureus. The strains from chicken are compared with strains of human, bovine, and ovine origin. An ecological study in a chicken farm has shown that S. aureus strains from chicken are not found in man and vice versa.The species Staphylococcus aureus can be subdivided into host-specific varieties (MEYER 1967, GRIGOROVA et al. 1976) and into biotypes (HAJEK and MARSALEK 1971). Host-specific-varieties or biotypes of S. aureus isolated from different ecological sources correspond to specific host animals and man, respectively, they show different biochemical characteristics and phage-patterns.The system of host-specific-varieties differentiates the species S. aureus into the varieties hominis, bovis, ovis, and canis and into strains which cannot be alloted to
Hum mel, R., G . L e h man n : Bovine coagulase-negative Staphylococci: Biochemistry and Polymerase Chain Reaction. Acta vet. Brno, 63,1994: 133-139.Staphylococcus (S.) simulans, S. chromogenes, and S. epidermidis were the species of coagulase-negative staphylococci (CNS) most frequently involved in subclinical mastitits of dairy cattle. The same biochemical features characterized the successive isolates of a particular chronically infected udder quarter. Occurrence rate of the various species differed between the herds examined. In cases of clinical mastitis of cows S. xylosus, S. simulans, S. haemolyticus, and S. chromogenes predominated. A comparison between strains of the particular CNS species from infections in man and cattle did not show host attributable biochemical features or profiles obtained by polymerase chain reaction using arbitrary primers (AP-PCR). Materials and Methods Bacterial strainsThe CNS examined in this study originated from cases of clinical mastitis (54 strains) and of subclinical mastitits (57 strains) in cattle. For comparison, 8 strains from infections in man were included in these studies.Of the strains from bovine clinical mastitis 41 were isolated from udder secretions in 39 dairy herds submitted for bacteriological examination to the regional veterinary laboratory. An additional 13 strains originated from Belgium.The 57 strains from subclinical mastitis were selected in five large herds of cattle (Table 1) with 300 to 500 cows each. An infection of the mammary gland means isolation of CNS in pure culture together with an elevated total cell count (>300 000 cells/ml milk). Sampling of udder secretions was carried out before and after milking. Repeated isolates from a particular udder quarter possessed of the same biochemical features were considered a single strain. The 57 strains represented a total of 580 isolates. All of the herds practised post milking teat dipping but only two of them (herds Np and Lu) applied a proper hygiene at milking. There was an occasional history of Streptococcus agalacriae in these herds and the infected cows were removed for slaughter.In herd Np quarter milk samples from 463 cows at freshening were investigated for the presence of CNS infections. 21 cows with 29 chronically CNS infected quarters in herd Np were resampled monthly or bimonthly to the next freshening. The 29 strains represented a total of 502 isolates. In herds Mo and Zi, respectively, 7 out of 197 and 3 out of 293 cows could be found chronically infected. Three consecutive samplings were performed and a total of 42 isolates gathered. Herds Ka and Lu have been sampled only once.
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