lancet shaped streptococcus pneumoniae

Streptococcus pneumoniae (S. pneumoniae) are lancet-shaped, gram-positive, facultative anaerobic bacteria with over 90 known serotypes. Writing an ‘Encyclopedia’ article on the Pneumococcus was a risky undertaking in the era of Pubmed and Google search: Highly specific and detailed information fitting a reader’s particular curiosity is instantly available upon pushing a few buttons on the computer.

Of the These peptidases are also known as penicillin-binding proteins because they are the binding sites for a variety of ß-lactam antibiotics.

However, since the production of a CPS is such a defining trait of pneumococci, these have been subject to particularly stringent tests to confirm their identification as S. pneumoniae [10]. Perform urine antigen detection in adults (≈70% sensitive in adults with bacteremia; not specific in children).

A greater knowledge of the biology of pneumococci resulted in new diagnostic tests that together with a revision of the breakpoints defining resistance to penicillin and the advent of conjugate vaccines, are changing our understanding of the burden of pneumococcal disease and our approaches to prevent and treat infections by this important pathogen. To further simplify this process, several “genetic serotyping” schemes have been developed to identify particular characteristics of the cps loci.

The surface proteome of a pathogen is an essential toolbox for its ability to colonize and persist in its host. Monitoring two key host markers, C-reactive protein and procalcitonin, appears to increase the specificity of PCR assays in the diagnosis of pneumococcal lower respiratory tract infection [23]. Maturation of the skull shape to optimally ventilate the middle ear and sinuses may play a role, and the development of capsule and protein-responsive mucosal immunity reduces disease with age. Humans are (almost) the sole pneumococcal host.

Selective predisposition to bacterial infections in IRAK-4-deficient children: IRAK-4-dependent TLRs are otherwise redundant in protective immunity.

Bacteremia with Streptococcus pneumoniae is always symptomatic.
Penicillin enhances the toll-like receptor 2-mediated proinflammatory activity of. The Statens Serum Institut in Copenhagen, Denmark, is the most frequent source of sera to identify pneumococcal capsules.

S. pneumoniae multiplies rapidly in the alveolar spaces, and produce inflammatory cells which fills the alveoli and/or lungs. Moreover, S. pneumoniae is catalase-negative and α-hemolytic. The mass profile of MALDI-TOF systems deployed in clinical microbiology laboratories is generated primarily by ribosomal proteins facilitating the alignment with current taxonomical classifications.

New insights into the pathogenic mechanisms of this species confirmed the key role of the capsular polysaccharide but have also identified the important functions played by proteins in the interaction with the host. Mario Ramirez, in Molecular Medical Microbiology (Second Edition), 2015.

However, the persistently high case fatality rate associated with pneumococcal disease (especially bacteremia) despite antibiotic administration bespeaks the continued contributory role of host defenses in successfully responding to infection. TNF-alpha compensates for the impaired host defense of IL-1 type I receptor-deficient mice during pneumococcal pneumonia. However, the emergence of optochin-resistant variants [3] has brought into question the validity of using this sole test for the presumptive identification of pneumococci. Combined therapy with a β-lactam and macrolide may improve outcomes.

Brock Biology of Microorganisms, 12th edition. R. Sá-Leão, A. Tomasz, in Encyclopedia of Microbiology (Third Edition), 2009. In liquid medium, pneumococci may also be found growing in chains. Pathogen recognition and innate immunity. Strategies for the control of pneumococcal disease. These proteins have diverse roles in the interaction of the pneumococcus with its host, such as adhesion to epithelial cells and extracellular matrix proteins, substrate transport, immune evasion, and bacterial fitness.

Vaccine escape recombinants emerge after pneumococcal vaccination in the United States.

The prevention of pneumococcal pneumonia is largely based on immunization using pneumococcal vaccine and the effective treatment of affected individuals. The exact mechanism of this protective effect is not known; it is likely a combination of the lack of capsular receptors on phagocytes, repellent electrochemical forces on the capsule, and the ability of the capsule to mask opsonizers such as antibody and complement. This chapter summarizes the current knowledge of how pneumolysin and major adhesins manipulate host signaling pathways. However, this technique requires specific expertise, so more recently, the Statens Serum Institut has made a latex agglutination test available, which allows a more streamlined procedure for serotyping pneumococci [11]. Other studies indicate that the estimated pneumococcal load in blood is correlated with disease severity and could potentially be used to distinguish between colonization and infection [23,24].

Otitis media is the most common clinical syndrome, but pneumococcal pneumonia in children and adults underlies most serious infections and death. Daniel R. Neill, ... Aras Kadioglu, in Encyclopedia of Immunobiology, 2016.
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The apoptotic response to pneumolysin is Toll-like receptor 4 dependent and protects against pneumococcal disease. In conclusion, pneumococcal infection results in different degrees of inflammatory responses and tissue damage at each compartment as tolerance capacity varies between infection sites (Figure 20.1).

Copyright © 2020. The spectrum of infection ranges from asymptomatic pharyngeal colonization to mucosal disease (otitis media, sinusitis, pneumonia) to invasive disease (bacteria in a normally sterile site; bacteremia, meningitis, empyema, endocarditis, arthritis). In the more widely used Danish system, serotypes are grouped based on antigenic similarities and given both a number and a letter (eg, 19A, 19B, and 19C). Madigan M.T., Martinko J.M., Dunlap P.V and Clark D.P (2009). We use cookies to help provide and enhance our service and tailor content and ads.

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