scholarly journals THE ANTISTREPTOCOCCAL PROPERTY OF MILK

1952 ◽  
Vol 95 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Armine T. Wilson ◽  
Herman Rosenblum
Keyword(s):  
Goat Milk ◽  
Cow Milk ◽  
Group A Streptococci ◽  
Highly Sensitive ◽  
Group A ◽  
Resistant Strains ◽  
Intermediate Degree

The measurement in vitro of lactenin, the antistreptococcal substance of milk, is affected by the size of the inoculum, the temperature of incubation, and the type of medium employed. Hemolytic streptococci belonging to the several serological groups vary in susceptibility to lactenin. All group A streptococci, regardless of type, are highly sensitive to it, and milk receiving a small inoculum sterilizes itself within 48 hours or less. By contrast, most strains of groups B, C, D, and E, although they may temporarily be inhibited, ultimately achieve full growth. Strains belonging to groups F, G, H, K, and L vary in sensitivity, some being fully inhibited and others achieving full growth. When streaked on the surface of milk-agar plates and examined at the end of 24 hours the streptococci fall into two classes: sensitive strains which do not produce visible colonies on the plate, and resistant strains which grow excellently. Very few strains show an intermediate degree of sensitivity. Human and goat milk contain an antistreptococcal principle which appears to be the same as the lactenin of cow milk, since streptococci which are inhibited by milk from one species are inhibited by milk from the others, and vice versa.

Dynamic in vitro gastric digestion of infant formulae made with goat milk and cow milk: Influence of protein composition

2019 ◽  
Vol 97 ◽  
pp. 76-85 ◽  
Author(s):  
Aiqian Ye ◽  
Jian Cui ◽  
Elizabeth Carpenter ◽  
Colin Prosser ◽  
Harjinder Singh
Keyword(s):  
Goat Milk ◽  
Protein Composition ◽  
Cow Milk ◽  
Gastric Digestion ◽  
Infant Formulae

scholarly journals Antibodies against a Synthetic Peptide of SagA Neutralize the Cytolytic Activity of Streptolysin S from Group A Streptococci

2002 ◽  
Vol 70 (4) ◽  
pp. 2166-2170 ◽  
Author(s):  
James B. Dale ◽  
Edna Y. Chiang ◽  
David L. Hasty ◽  
Harry S. Courtney
Keyword(s):  
Synthetic Peptide ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Convincing Evidence ◽  
Cytolytic Activity ◽  
M Protein ◽  
Group A Streptococci ◽  
Streptolysin S ◽  
Group A

ABSTRACT Virtually all group A streptococci (GAS) produce streptolysin S (SLS), a cytolytic toxin that is responsible for the beta-hemolysis surrounding colonies of the organisms grown on blood agar. SLS is an important virulence determinant of GAS, and recent studies have identified a nine-gene locus that is responsible for synthesis and transport of the toxin. SLS is not immunogenic; thus, no neutralizing antibodies are evoked during the course of natural infection. In the present study, we show that a synthetic peptide containing amino acid residues 10 to 30 of the putative SLS (SagA) propeptide [SLS(10-30)] coupled to keyhole limpet hemocyanin evoked antibodies in rabbits that completely neutralized the hemolytic activity of the toxin in vitro. Inhibition of hemolysis was reversed by preincubation of the immune serum with soluble, unconjugated peptide, indicating the specificity of the antibodies. In addition, antibodies that were affinity purified over an SLS(10-30) peptide column completely inhibited SLS-mediated hemolysis. The SLS(10-30) antisera did not opsonize group A streptococci; however, when combined with type-specific M protein antisera, the SLS antibodies significantly enhanced phagocytosis mediated by M protein antibodies. Thus, we have shown for the first time that it is possible to raise neutralizing antibodies against one of the most potent bacterial cytolytic toxins known. Our data also provide convincing evidence that the sagA gene actually encodes the SLS peptide of GAS. The synthetic peptide may prove to be an important component of vaccines designed to prevent GAS infections.

scholarly journals STUDIES ON THE PATHOGENICITY OF GROUP A STREPTOCOCCI

1959 ◽  
Vol 110 (4) ◽  
pp. 617-628 ◽  
Author(s):  
Marie Judith Foley ◽  
W. Barry Wood
Keyword(s):  
Hyaluronic Acid ◽  
Virulent Strain ◽  
Critical Role ◽  
M Protein ◽  
Group A Streptococci ◽  
Streptococcal Infections ◽  
Full Complement ◽  
Group A ◽  
Hyaluronic Acid Capsule

A quantitative study of the combined antiphagocytic effects of the M protein and the hyaluronic acid capsules of four strains of Group A streptococci revealed the following facts relating to their intraperitoneal virulence in mice and rats: 1. The most virulent strain, S23M (matt), produced both a large hyaluronic acid capsule and a full complement of M protein, the combined effects of which rendered the organism highly resistant to surface phagocytosis. 2. The slightly less virulent strain, T14/46 (matt virulent) was somewhat more susceptible to surface phagocytosis owing to the fact that its smaller capsule was less antiphagocytic than that of the S23M organism. 3. The glossy variant of the S23 strain (S23G), which ranked third in virulence, was still more susceptible to surface phagocytosis because of its lack of detectable M substance. Its large hyaluronic acid capsule, however, was capable of protecting it against phagocytosis on glass. 4. The least virulent strain, T14 (matt avirulent), was the most susceptible of all to phagocytosis. Though it possessed both M substance and capsule, which together prevented its phagocytosis on glass, each of them was shown to be quantitatively and functionally deficient as compared to Strain S23M. The differences in phagocytability, which appear to be directly related to the pathogenicity of the organisms, could be adequately demonstrated in vitro only by phagocytic tests designed to measure surface phagocytosis in the absence of opsonins. This fact is in keeping with the observation, previously reported, that surface phagocytosis plays a critical role in the defense of the host, particularly during the earliest stages of experimental streptococcal infections. Its possible relation to suppuration during the later stages of infection is also discussed.

Isolation of Group A Streptococci with Reduced In Vitro β-Lactam Susceptibility Harboring Amino Acid Substitutions in Penicillin-Binding Proteins in Japan

2021 ◽  
Author(s):  
Tsubasa Ikeda ◽  
Rihito Suzuki ◽  
Wanchun Jin ◽  
Jun-ichi Wachino ◽  
Yoshichika Arakawa ◽  
...  
Keyword(s):  
United States ◽  
Amino Acid ◽  
Streptococcus Pyogenes ◽  
The United States ◽  
Amino Acid Substitutions ◽  
Group A Streptococci ◽  
Penicillin Binding Protein ◽  
Penicillin Binding Proteins ◽  
Group A

Streptococcus pyogenes (group A Streptococcus , GAS) has long been regarded as being susceptible to β-lactams. However, amino acid substitutions in penicillin-binding protein (PBP)2X conferring reduced in vitro β-lactam susceptibility have been indicated since 2019 in the United States and Iceland. Here, we report the first isolation of Streptococcus pyogenes possessing the PBP2X substitution conferring reduced in vitro β-lactam susceptibility in Asia; however, the MICs were below the “susceptible” breakpoint of the CLSI.

Antibiotic Resistance: Relationship to Persistence of Group A Streptococci in the Upper Respiratory Tract

PEDIATRICS ◽  
1996 ◽  
Vol 97 (6) ◽  
pp. 971-975
Author(s):  
Michael A. Gerber
Keyword(s):  
Respiratory Tract ◽  
Upper Respiratory Tract ◽  
Beta Lactam ◽  
Erythromycin Resistance ◽  
In Vitro Susceptibility ◽  
Beta Lactam Antibiotics ◽  
Group A ◽  
Resistant Strains ◽  
Upper Respiratory

Despite the use of penicillin for more than 40 years in treating GABHS infections, there has been no significant change in the in vitro susceptibility of GABHS to penicillin. Reported failures to eradicate GABHS from the upper respiratory tracts of patients with pharyngitis and the apparent resurgence of serious Group A streptococcal infections and their sequelae probably are not related to the emergence of penicillin resistance. Although erythromycin resistance in GABHS had been a major problem in Japan and continues to be a major problem in Finland, it has not been a problem in this country. The susceptibility of GABHS to the newer macrolide antibiotics appears to be similar to that of erythromycin. Comprehensive, community-wide programs to continuously monitor for erythromycin resistance in GABHS would be difficult to justify. However, because little is known about how erythromycin resistance in GABHS is acquired or spread, it would be reasonable to periodically monitor isolates of GABHS for erythromycin resistance. A substantial proportion of GABHS are currently resistant to tetracyclines and these agents are inappropriate for treating GABHS infections. Although little recent information is available about the susceptibility of GABHS to sulfonamides, these agents have been shown to be ineffective in eradicating GABHS from the upper respiratory tract regardless of the in vitro sensitivities. GABHS have not been shown to be resistant to any of the commonly used oral cephalosporins; however, there is a great deal of variability among these agents in their activity against GABHS. Clindamycin resistance in GABHS has remained unusual. This agent is an alternative for treating GABHS infections due to macrolide-resistant strains in patients who cannot be treated with beta-lactam antibiotics. There is no reason, based on the in vitro susceptibilities of GABHS, to change the current recommendations for treating GABHS infections with penicillin and for using erythromycin for patients who are allergic to penicillin.

scholarly journals FATE OF NON-VIRULENT GROUP A STREPTOCOCCI PHAGOCYTIZED BY HUMAN AND MOUSE NEUTROPHILS

1957 ◽  
Vol 106 (6) ◽  
pp. 777-786 ◽  
Author(s):  
Armine T. Wilson ◽  
Grove G. Wiley ◽  
Pauline Bruno
Keyword(s):  
Electric Current ◽  
Peripheral Blood ◽  
Group A Streptococci ◽  
Blood Neutrophils ◽  
Group A ◽  
Time Required ◽  
Human And Mouse ◽  
Virulent Group

The fate of non-virulent group A streptococci phagocytized in vitro has been investigated by destroying the phagocyte with electric current and observing whether the liberated cocci multiply. Human and mouse peripheral blood neutrophils quickly injure ingested cocci, the time required to produce 50 per cent non-survival of chains being 8 and 6¾ minutes, respectively.

Association of chloramphenicol resistance of group A streptococci with host-controlled restriction and modification of bacteriophages

1971 ◽  
Vol 17 (12) ◽  
pp. 1573-1576
Author(s):  
Patric L. Friend
Keyword(s):  
Group A Streptococci ◽  
Resistance Level ◽  
Chloramphenicol Resistance ◽  
Group A ◽  
Resistant Strains ◽  
Sensitive Group

Bacteriophages grown on chloramphenicol (CM)-sensitive group A streptococci plate efficiently only on other CM-sensitive strains, while phages propagated on CM-resistant strains plate well only on CM-resistant hosts. Data are presented showing that the phages are subject to host-controlled modification and restriction, and that these processes are related to the CM resistance level of the host.

scholarly journals Comparison of the Bifidogenic Effects of Goat and Cow Milk-Based Infant Formulas to Human Breast Milk in an in vitro Gut Model for 3-Month-Old Infants

2020 ◽  
Vol 7 ◽  
Author(s):  
Sophie Gallier ◽  
Pieter Van den Abbeele ◽  
Colin Prosser
Keyword(s):  
Human Milk ◽  
Infant Formula ◽  
Goat Milk ◽  
Cow Milk ◽  
Common Source ◽  
Human Breast Milk ◽  
Infant Formulas ◽  
Infant Gut Microbiome

Human milk contains prebiotic components, such as human milk oligosaccharides (HMOs), which stimulate the growth of specific members of the infant gut microbiota (e.g., Bifidobacteria). Plant-based or synthetic oligosaccharides are often added to infant formulas to simulate the bifidogenic effect of HMOs. Cow milk, the most common source of protein in infant formula, and goat milk, used increasingly in the manufacture of infant formula, contain naturally-occurring prebiotics. This study compared the upper gastrointestinal digestion and subsequent colonic fermentation of human milk vs. goat and cow milk-based infant formulas (goat IF and cow IF, respectively), without additional oligosaccharides using an in vitro model for 3-month-old infants based on the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). First, a dialysis approach using 3.5 kDa membranes was demonstrated to simulate small intestinal absorption of carbohydrates in conditions similar to those in vivo. During the in vitro digestion experiment, oligosaccharides were detected in human milk and goat IF but barely detected in the cow IF. Further, all three milk matrices decreased colonic pH by boosting acetate, lactate, and propionate production, which related to increased abundances of acetate/lactate-producing Bifidobacteriaceae for human milk (+25.7%) and especially goat IF (33.8%) and cow IF (37.7%). Only cow IF stimulated butyrate production which correlated with an increase in Lachnospiraceae and Clostridiaceae. Finally, Enterobacteriaceae and Acidaminococcaceae also increased with all three milk matrices, while production of proteolytic metabolites (branched-chain fatty acids) was only detected for the cow IF. Overall, goat and cow milk-based formulas without added oligosaccharides impacted gut microbial activity and composition similarly to human milk. This suggests that even without supplementation of formula with oligosaccharides, whole goat milk, whole cow milk and cow milk ingredients already supply compounds in formulas that exert beneficial bifidogenic effects. Further clinical research is warranted to elucidate the effect of whole goat milk-based formulas on the infant gut microbiome.

Sign in / Sign up

Export Citation Format

Share Document