Role of Protein A in the Serum-Soft Agar Technique

Forsum, Urban; Forsgren, Arne; Hjelm, Eva

doi:10.1128/iai.6.4.583-586.1972

Cited by 14 publications

(6 citation statements)

References 21 publications

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“…The mechanism of diffuse colony formation by encapsulated and slime-producing S. aiureus strains is not fully understood. It has been suggested that compact colony formation by unencapsulated strains is due to a reaction between protein A and the Fc of immunoglobulin G molecules, which results in the adherence of daughter cells during colony development (10,11). The staphylococcal capsule is readily penetrated by high-molecular-weight proteins (14,30), and one of us has proposed (28) that immunoglobulin G reacts with cell wall protein A and becomes buried in the mass of the capsule.…”

Section: Discussionmentioning

confidence: 99%

Slime production by bovine milk Staphylococcus aureus and identification of coagulase-negative staphylococcal isolates

Rather¹,

Davis²,

Wilkinson³

1986

J Clin Microbiol

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Staphylococcus aureus isolates from bovine milk were assessed for capsule or slime production. When pure S. aureus cultures in milk were inoculated directly into serum-soft agar constituted with a modified staphylococcus 110 medium, 100% of the isolates grew with diffuse colony morphology. Diffuse colony morphology was rapidly lost on subculture and was more rapidly lost in brain heart infusion-serum-soft agar. No evidence was seen for encapsulation in India ink preparations or by the clumping factor test. It was concluded that freshly isolated S. aureus strains produce slime, not true capsules. During examination of the 84 milk samples that grew staphylococci in addition to S. aureus (27.4%), a significant number of coagulase-negative staphylococcal species were encountered and identified by conventional tests as S. simulans (41.7%), S. xylosus (11.9%), S. epidermidis (3.6%), S. saprophyticus (3.6%), S. hyicus (2.9%), S. cohnii (1.2%), S. haemolyticus (1.2%), and S. warneri (1.2%). Five isolates (6.0%) were not identified. Attempts were also made to identify the isolates by the API Staph-Ident system, which gave an overall accuracy of 45.2%. The susceptibilities of the isolates to a variety of antibiotics were determined, and they appeared to be less resistant than human clinical isolates.

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Section: Discussionmentioning

confidence: 99%

Slime production by bovine milk Staphylococcus aureus and identification of coagulase-negative staphylococcal isolates

Rather¹,

Davis²,

Wilkinson³

1986

J Clin Microbiol

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“…Protein A in S. aureus is found predominantly in covalent linkage to cell wall peptidoglycan (23) and is uniformly distributed throughout the cell wall (9). The encapsulated S. aureus strains M and Smith diffuse have been shown to contain protein A by Forsum et al (5), who used a hemagglutination assay of extracted protein A with sensitized sheep erythrocytes. In the present investigation we have taken advantage of this fact to study the passage of IgG through the S. aureus capsular layer to IgG-binding protein A located in the cell wall.…”

Section: Discussionmentioning

confidence: 99%

“…Forsum et al (5) proposed that the capsule prevented the reaction between protein A and IgG in intact encapsulated cells. Our experiments confirm the occurrence of protein A in the M and Smith diffuse strains and show that the reaction between protein A and IgG does occur in the intact bacteria.…”

Section: Discussionmentioning

confidence: 99%

Binding of human immunoglobulin G to protein A in encapsulated Staphylococcus aureus

King¹,

Wilkinson²

1981

Infect Immun

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Recent studies of the mechanism of resistance to phagocytosis in encapsulated Staphylococcus aureus have suggested that the capsule is readily penetrated by high-molecular-weight proteins such as antibodies and complement components. S. aureus strains contain a cell wall protein, protein A, that reacts with the Fc portion of immunoglobulins. The binding of immunoglobulin G (IgG) to encapsulated and unencapsulated S. aureus strains has been studied to assess the penetrability of the S. aureus capsule by IgG. Encapsulated S. aureus strains M and Smith diffuse bound large amounts of human IgG which were comparable to amounts bound by the unencapsulated strains Cowan I, M variant, and Smith compact. Trypsin treatment of bacteria reduced their ability to bind IgG. Bound IgG was not removed by extensive washing of bacteria with buffer. A non-protein A-containing, coagulase-negative, encapsulated staphylococcal strain did not bind IgG. These observations suggest that IgG is binding to cell wall protein A in encapsulated S. aureus. No differences in the rates of IgG binding by encapsulated and unencapsulated S. aureus strains were observed. It is concluded that the S. aureus capsule is freely permeable to IgG. This is of importance in considerations of the mechanisms of resistance to phagocytosis and antigen masking in encapsulated microorganisms.

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“…Hasil penelitian pada ikan nila yang terinfeksi streptococcosis di Indonesia diidentifikasi dari golongan bakteri S. agalactiae sebagai agen penyebabnya (Lusiastuti, A.M., Textor, M., Seeger, H., Akineden, Ö., & Zschöck, M. 2014;Suhermanto, A., Sukenda, S., Zairin, J.M., Lusiastuti, A.M., & Nuryati, S. 2018 (Forsum, U., Forsgren, A., & Hjelm, E. 1972;Prasiddhanti, L., & Wahyuni, A. E. T. H. 2015).…”

Section: Pendahuluanunclassified

Karakteristik Bakteri Streptococcus agalactiae NP104O, S01-196-16 dan NMbO Penyebab Streptococcosis pada Ikan Nila (Oreochromis niloticus)

Suhermanto¹,

Herdianto²,

Suhermin³

et al. 2019

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Kegagalan budidaya ikan nila di Indonesia pada segmen pembenihan, pendederan dan pembesaran salah satunya disebabkan oleh infeksi Streptococcus agalactiae. Penelitian ini bertujuan untuk mendeteksi karakteristik bakteri S. agalactiae NP104O, S01-196-16 dan NMbO yang menginfeksi budidaya ikan nila. Isolasi bakteri dilakukan saat terjadi wabah streptococcosis, pengujian berdasarkan karakter morfologi dan biokimia. Uji patogenisitas dilakukan dengan menginjeksikan bakteri ke ikan dengan dosis 107 CFU ikan-1. Hasil uji menunjukkan ketiga isolat Gram positif, berbentuk kokus, katalase negatif, dan oksidase negatif. Ketiga isolat memiliki pola pertumbuhan dan konsentrasi yang berbeda hingga akhir pengamatan. Uji patogenisitas diperoleh hasil, semua ikan yang diinjeksi bakteri NP104O, S01-196-16 dan NMbO muncul gejala klinis melanosis, unilateral atau bilateral exophthalmos, kekeruhan pada mata, tulang belakang melengkung membentuk huruf C, erratic, dan whirling. Diharapkan, hasil penelitian ini bisa dijadikan referensi untuk tindakan pencegahan infeksi streptococcosis pada ikan nila.

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Role of Protein A in the Serum-Soft Agar Technique

Abstract: Formation of compact colonies of Staphylococcus aureus in serum-soft agar is mainly a result of a reaction between protein A and the Fc-part of immunoglobulin G and not a clumping factor-fibrinogen reaction.

Cited by 14 publications

References 21 publications

Slime production by bovine milk Staphylococcus aureus and identification of coagulase-negative staphylococcal isolates

Slime production by bovine milk Staphylococcus aureus and identification of coagulase-negative staphylococcal isolates

Binding of human immunoglobulin G to protein A in encapsulated Staphylococcus aureus

Karakteristik Bakteri Streptococcus agalactiae NP104O, S01-196-16 dan NMbO Penyebab Streptococcosis pada Ikan Nila (Oreochromis niloticus)

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