Streptococci Of Animal Origin Research Articles

Molecular basis of resistance to macrolides and lincosamides among staphylococci and streptococci from various animal sources collected in the resistance monitoring program BfT-GermVet

In this study, erythromycin- and/or clindamycin-resistant isolates among 248 coagulase-positive and coagulase-variable staphylococci and 500 streptococci, collected all over Germany during 2004–2006 in the resistance monitoring program BfT-GermVet, were investigated for their genetic basis of macrolide and/or lincosamide resistance. Staphylococci were sampled from various disease conditions of dogs/cats or pigs, whereas streptococci were from dogs/cats, pigs or horses. Resistant staphylococci were further identified biochemically to species and subspecies level and tested for the resistance genes erm(A), erm(B), erm(C), erm(TR), msr(A), msr(D), mef(A), mph(C), lnu(A), lnu(B) and lnu(C). The methylase genes erm(A), erm(B) and erm(C) were detected in staphylococci, alone or in different combinations. The erm(B) gene was the predominant gene in Staphylococcus intermedius and streptococci. The efflux gene msr(A) and the genes mph(C) and lnu(A) coding for inactivating enzymes were detected in single staphylococcal isolates. The efflux genes mef(A) and msr(D) were detected in three streptococci, in one of them together with the erm(B) gene. The lnu(B) gene was detected in seven porcine streptococcal isolates with reduced susceptibility to clindamycin. These data confirm that high-level resistance to erythromycin and clindamycin in staphylococci and streptococci was mainly due to rRNA methylases. The lnu(B) gene was detected for the first time in streptococci of animal origin.

Bacteriocin-like activity production and resistance in selected enterococci and streptococci of animal origin

Antimicrobial proteins and peptides produced by bacteria, termed bacteriocins, are widely acknowledged to be important contributors to their producer organism survival. Enterocin A, enterocin B, enterocin P and enterolysin A belong to the best studied enterocins, i.e., bacteriocins produced by enterococci and streptococci. Twenty-one enterococcal and seven streptococcal isolates were analysed for bacteriocin-like activity production and resistance by overlay test. Up to 50% of tested strains showed antibacterial activity at least against one indicator strain. The occurrence of enterocin B structural gene in several isolates was confirmed by PCR method. The results of this study should broaden knowledge of bacteriocin-like activity production and resistance among gram-positive bacteria.

The serotyping of hospital strains of streptococci belonging to Lancefield group C and group G.

A collection of more than 300 strains belonging to either Lancefield group C or group G was made. The cultures had been isolated either sporadically from patients with serious disease or as apparent clusters from various nosocomial outbreaks. T-protein antigens were sought. So far, nine distinct serotypes have been found among the group G streptococci and seven serotypes amongst the Streptococcus equisimilis (group C) strains. Of the sixteen serotypes, four were the original T-types 7, 16, 20 and 21 described by Griffith (1934). Because of the similarities of representatives of the two groups to Lancefield group A streptococci (Griffith, 1934; Maxted & Potter, 1967) a few strains not unexpectedly carried T antigens usually seen in group A streptococci. Using this scheme it has been possible to serotype 76% of S. equisimilis strains of human origin and 82% of group G streptococci from human clinical material. A small collection of group C and group G streptococci of animal origin could not be serotyped with the experimental T-antisera.

Fibrinogen Binding Structures in β‐Hemolytic Streptococci Group A, C, and G

Binding of radiolabelled fibrinogen was measured to 197 strains of 16 different bacterial species. All streptococcal strains belonging to groups A, C, and G isolated from human sources were strongly positive. S. aureus strains showed low binding values. Occasional group B streptococci were positive. Reactive strains were also noted among group C streptococci of animal origin, Streptococcus zooepidemicus and Str. equii, and bovine beta-hemolytic group G streptococci. Bovine alpha-hemolytic group G strains as well as the remaining seven species of human origin were all negative. Inhibition experiments and correlation studies indicated that the streptococcal receptor for fibrinogen was different from immunoglobulin Fc binding reactivity. Comparisons with the newly discovered beta 2-microglobulin binding factor showed that trypsin concentrations which destroyed this receptor left the fibrinogen receptor intact. Although the two receptors correlate in strain population studies and show competition for binding the difference in trypsin sensitivity indicates that they represent two different structural entities. Both receptors might serve as basic markers for M-protein like surface components of Gram positive cocci.

Effect of Dissociation of Streptococci on their Fibrinolytic And Anticlotting Activity

Tillett and Garner1 made the interesting observation that broth cultures of beta hemolytic streptococci of human origin rapidly dissolve the normal human fibrin clot and that the dissolving action is dependent upon an extracellular substance. With the exception of some strains of Staphylococcus aureus, fibrinolysis appears to be peculiar to the hemolytic streptococcus and it has not been demonstrated with other bacteria including Streptococcus viridans, pneumococcus and most strains of hemolytic streptococci of animal origin. Hadfield, Magee and Perry2 found a greater variation in the dissolving power of their strains of hemolytic streptococci than described by others. They observed that the strains of hemolytic streptococci which were virulent for mice and formed colonies corresponding to the colonies called smooth in this country, were the strongest fibrinolytic strains. As their strains became less virulent they became less fibrinolytic. For my tests streptococci were grown 20 hours in meat extract 1 per cent dextrose broth, pH 7.0. If they would not grow in this medium one drop of defibrinated sheep blood was added to 5 cc. of dextrose broth. In general the method of Tillett and Garner was followed. As it is more convenient to use small amounts of blood, it is collected from the finger or ear into bent capillary pipets containing 2 per cent sodium citrate in salt solution. Two-tenths per cent potassium oxalate give the same results. Two parts of blood are drawn into a pipet containing one part of the anticoagulant and diluted at once with eight parts of physiological salt solution and centrifuged. The plasma is used within one hour after the blood has been collected, although it may be kept 24 hours in the ice box before using. Four parts of the diluted plasma are mixed with two parts of broth culture and one part of 0.25 per cent CaCl2 in small test tubes. The mixtures are incubated at 36-37 C. The control containing plasma, uninoculated broth and CaCU clots in from 5-15 minutes. When broth cultures of hemolytic streptococci dissolve the plasma clot, it occurs in from 15 minutes to 24 hours after its coagulation. Nineteen strains of hemolytic streptococci, from scarlet fever (8), erysipelas (6, including the pigmented yellow dissociant), septic sore throat (2),

The Identity of Streptococci of Animal Origin with Certain Strains of Str. epidemicus

The Identity of Streptococci of Animal Origin with Certain Strains of <i>Str. epidemicus</i>