This document summarizes key information about various Streptococcus bacteria. It describes their morphology, cultural characteristics, biochemical properties, pathogenic species and diseases caused. Streptococcus pyogenes, pneumoniae, viridans and faecalis are discussed in detail, outlining their laboratory diagnosis and treatment. Classification systems for streptococci include Lancefield grouping and hemolytic reactions on blood agar. Streptococcus pyogenes produces various virulence factors and causes impetigo, pharyngitis, and rheumatic fever. Pneumoniae commonly colonizes the nasopharynx and can lead to pneumonia or otitis media.
Gram-positive cocci include Staphylococcus (catalase-positive), which grows clusters, and Streptococcus (catalase-negative), which grows in chains. The staphylococci further subdivide into coagulase-positive (S. aureus) and coagulase-negative (S. epidermidis and S. saprophyticus) species. Streptococcus bacteria subdivide into Strep. pyogenes (Group A), Strep. agalactiae (Group B), enterococci (Group D), Strep viridans, and Strep pneumonia.
Gram-positive bacilli (rods) subdivide according to their ability to produce spores. Bacillus and Clostridia are spore-forming rods while Listeria and Corynebacterium are not. Spore-forming rods that produce spores can survive in environments for many years. Also, the branching filament rods encompass Nocardia and actinomyces.
Gram-positive organisms have a thicker peptidoglycan cell wall compared with gram-negative bacteria. It is a 20 to 80 nm thick polymer while the peptidoglycan layer of the gram-negative cell wall is 2 to 3 nm thick and covered with an outer lipid bilayer membrane.
Bloodstream infection mortality rates have increased by 78% in just two decades[1]. Gram-positive organisms have highly variable growth and resistance patterns. The SCOPE project (Surveillance and Control of Pathogens of Epidemiologic Importance) found that gram-positive organisms in those with an underlying malignancy accounted for 62% of all bloodstream infections in 1995 and 76% in 2000 while gram-negative organisms accounted for 22% and 14% of infections for these years.[2]
Gram-positive cocci include Staphylococcus (catalase-positive), which grows clusters, and Streptococcus (catalase-negative), which grows in chains. The staphylococci further subdivide into coagulase-positive (S. aureus) and coagulase-negative (S. epidermidis and S. saprophyticus) species. Streptococcus bacteria subdivide into Strep. pyogenes (Group A), Strep. agalactiae (Group B), enterococci (Group D), Strep viridans, and Strep pneumonia.
Gram-positive bacilli (rods) subdivide according to their ability to produce spores. Bacillus and Clostridia are spore-forming rods while Listeria and Corynebacterium are not. Spore-forming rods that produce spores can survive in environments for many years. Also, the branching filament rods encompass Nocardia and actinomyces.
Gram-positive organisms have a thicker peptidoglycan cell wall compared with gram-negative bacteria. It is a 20 to 80 nm thick polymer while the peptidoglycan layer of the gram-negative cell wall is 2 to 3 nm thick and covered with an outer lipid bilayer membrane.
Bloodstream infection mortality rates have increased by 78% in just two decades[1]. Gram-positive organisms have highly variable growth and resistance patterns. The SCOPE project (Surveillance and Control of Pathogens of Epidemiologic Importance) found that gram-positive organisms in those with an underlying malignancy accounted for 62% of all bloodstream infections in 1995 and 76% in 2000 while gram-negative organisms accounted for 22% and 14% of infections for these years.[2]
Lecture notes of Staphylococcus. A detailed account on the morphology, culture characteristics, biochemical characteristics, pathogenesis, laboratory diagnosis of S. aureus.
Bacteriology , Streptococcus species ,strep pyogenes, strep. Pneumoniae and strep fecalis. Diseases cause by Streptococcal microorganisms and how they can be managed. Cultural characteristics and morphology.
Neisseria is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, N. meningitidis and N. gonorrhoeae.
The presentation provide in depth knowledge about two of the most affecting bacteria to human health. They are Neisseria ( causing gonorrhea and Meningitis) and Shigella ( Diarrhea)
Lecture notes of Staphylococcus. A detailed account on the morphology, culture characteristics, biochemical characteristics, pathogenesis, laboratory diagnosis of S. aureus.
Bacteriology , Streptococcus species ,strep pyogenes, strep. Pneumoniae and strep fecalis. Diseases cause by Streptococcal microorganisms and how they can be managed. Cultural characteristics and morphology.
Neisseria is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens, N. meningitidis and N. gonorrhoeae.
The presentation provide in depth knowledge about two of the most affecting bacteria to human health. They are Neisseria ( causing gonorrhea and Meningitis) and Shigella ( Diarrhea)
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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2. STREPTOCOCCUS
• Streptococci is Gram-positive spherical/ovoid
• cocci arranged in long chains; commonly in
pairs.
• Streptococci are classified according to their
ability to break down blood in fresh blood
agar plates. Some streptococci have no effect
on blood ( non-haemolytic streptococci).
3. General Characteristics of
Streptococci
• Gram-positive spherical/ovoid cocci arranged in
long chains; commonly in pairs.
• Non-spore-forming, nonmotile. Can form
capsules
• Facultative anaerobes
• Most parasitic forms are fastidious and require
enriched media.
• Small, non pigmented colonies.
• Sensitive to drying, heat, and disinfectants.
5. • Classification of streptococci
includes;
• Classification system is based on hemolytic
reactions.
• β - hemolytic – A, B, C, D and G (Streptococcus
pyogenes)
• α - hemolytic – Streptococcus pneumoniae and
viridans
• γ – hemolytic – Streptococcus faecalis
• Lancefield classification of b – hemolytic
streptococci based on presence of carbohydrate
antigen in cell wall – 17 groups(A, B, C,….)
14. Cultural characteristics
• Facultative anaerobes.
• Best growth achieved at pH 7.4-7.6 and
temperature 37⁰C.
• Required enriched media for growth.
• Colonies are around 1mm in diameter,
surrounded by a zone of clear hemolysis, semi
transparent and vary in appearance.
15.
16. Biochemical properties
• They Produces many virulence factors. Means
that there is production of enzymes and
toxins.
17. Virulence factors of Streptococcus
Pyogenes
Enzymes:
• Streptokinase – digests fibrin clots
• Hyaluronidase – breaks down connective tissue
• DNase – hydrolyzes DNA
Toxins :
• Streptolysins (hemolysins):- streptolysin O (SLO) and
streptolysin S (SLS) – both cause cell and tissue injury.
• Erythrogenic toxin (pyrogenic):- Induces fever and
typical red rash.
• Superantigens:- Strong monocyte and lymphocyte
stimulants; cause the release of tissue necrotic factor.
18. Pathogenesis
• Humans are the only reservoir.
• In apparent carriers.(visible carriers of toxins and
enzyme)
• Transmission is through contact, droplets, food,
fomites
• Portal of entry is generally through skin or pharynx.
• Children are predominant group affected for cutaneous
and throat infections
• Systemic infections and progressive diseases may occur
if untreated.
19. Streptococcus pyogenes diseases
• Impetigo (pyoderma)- It is a skin infection with
superficial lesions that break and form highly
contagious crust.
• Throat infections
• Rheumatic fever – It has subclinical pharyngitis
in children; carditis with extensive heart valve
damage possible, arthritis, chorea, fever.
• Acute glomerulonephritis – It is the
inflammation of the nephrons.
24. Laboratory diagnosis
• Streptococcus pyogenes is frequently isolated
from samples such as skin, throat, sputum,
urine, and blood.
• Different methods for laboratory diagnosis of
Streptococcus pyogenes are:
Gram staining
Culture
Catalase test
25. Gram staining
• The diagnosis is suggested by the finding of
gram positive bacteria cocci in chains in the
sample.
26. Culture
• The organism is cultured on blood agar with
an added bacitracin antibiotic disk to show
beta-hemolytic colonies and sensitivity (zone
of inhibition around the disk) for the
antibiotic.
27. Catalase test
• Transfer a small amount of bacterial colony to
a surface of clean, dry glass slide using a loop
or sterile wooden stick. Place a drop of 3%
H2O2 on to the slide and mix. A positive result
is the rapid evolution of oxygen (within 5-10
sec.) as evidenced by bubbling. A negative
result is no bubbles or only a few scattered
bubbles. Streptococcus Pyogenes are catalase
negative.
28.
29. Treatment
• Streptococcus Pyogenes infections are treated
with penicillin
• Erythromycin is recommended for patients
who are allergic to penicillin.
30. Prevention
• Long-term penicillin prophylaxis for people
with a history of rheumatic fever or recurrent
strep throat.
• Streptococcus Pyogenes infections are best
prevented through effective hand hygiene.
31. STREPTOCOCCUS PNEUMONIAE
• These are commonly seen in nasopharynx of
healthy persons. It will not cause any illness
itself unless a viral infection or other factors
provokes.
32. Morphology
• They are gram positive cocci.
• Measures 0.5 – 1.25 μm
• Non motile and non sporing
• Capsulated
• Small, oval-shaped cells arranged in pairs and
short chains.
33.
34. Cultural characteristics
• Culture requires blood or chocolate agar.
• Growth improved by 5-10% CO2.
• Facultative anaerobes.
• Best growth achieved temperature 25 - 40⁰C.
• Colonies are surrounded by greenish
hemolysis under aerobic conditions and clear
under anaerobic conditions.
35.
36. Biochemical properties
• No significant toxin is produced in pneumococci.
• Presence of some of the extra cellular products
• – Haemolysin
• – Immunoglobilin A1 protease
• – Neuraminidase
• – Hyaluronidase
• Lack catalase and peroxidases.
• Ferment glucose, lactose and sucrose with
production of acid.
37. Pathogenesis
• 5-50% of all people carry it as normal flora in
the nasopharynx.
• Young children, elderly, immune
compromised, those with other lung diseases
or viral infections, are at risk.
• Pneumococci multiply and induce an
inflammatory response.
• Gains access to middle ear by way of
eustachian tube.
39. Laboratory diagnosis
• Streptococcus Pneumococci is frequently isolated
from samples such as sputum, blood, wound, CSF.
• Different methods for laboratory diagnosis of S.
Pneumococci are:
Gram staining
Quellung test
Culture
Catalase test
41. Quellung test
• The characteristic capsule can be best
detected using the Quellung test. In this test,
application of antiserum followed by staining
with India ink causes the capsule to appear
like a halo around the organism. The capsule is
also visible in smears stained with methylene
blue.
42.
43. Culture
• The organism is cultured on blood agar or
chocolate agar with incubation in an
environment of carbon dioxide. The organism
is cultured on blood agar with an added
optochin disk to show alphahemolytic
colonies.
46. Treatment and Prevention
• Traditionally treated with penicillin G or V.
• Broad spectrum antibiotics are recommended
for patients who are allergic to penicillin.
• Two vaccines available for high risk
individuals:
– Capsular antigen vaccine for older adults and
other high risk individuals – effective 5 years.
– Conjugate vaccine for children 2 to 23 months.
47. Streptococcus Viridans
• It is alpha haemolytic streptococci.
• It is oval in shape and found in short chains.
• It has six species groups (viridans group);
Streptococcus mutans, Streptococcus oralis, Streptococcus
salivarus,
Streptococcus sanguis, Streptococcus milleri, Streptococcus
mitis.
• Found in gums and teeth, oral cavity, and also in
nasopharynx, genital tract, skin.
• Not very invasive; dental or surgical procedures facilitate
entrance.
• It causes dental caries, sepsis and endocarditis.
• Persons with preexisting heart conditions should receive
prophylactic antibiotics before surgery or dental
procedures.
48. Streptococcus Faecalis
• It is also known as enterococci.
• It is a Gram-positive
• Oval cocci in pairs or short chains.
• Identified in MaConkey agar. Colonies are magenta in
color and pin point.
• It can grow in the range of 10 to 45°C and survive at
temperatures of 60°C for 30 min.
• It is non-motile, facultative anaerobic microbe.
• It ferments glucose and does not produce a catalase.
• It is associated with urinary tract infections, biliary tract
infections, septicemia, endocarditis and intra
abdominal abscess.
• Aminogycosides are drug of choice.
49.
50. References
1. Ananthanarayan R. & Paniker C. J. (2009).
Textbook of Microbiology. Hyderabad:
Universities Press (India) Private Limited.
2. Harvey Richard A. et all. Lippincott’s Illustrated
Reviews Microbiology, Wolters Kluwer (India) Pvt.
Ltd.,2nd edition.
3. Chakraborty P. (2009). A Textbook of
Microbiology. Kolkata: New Central Book Agency
(P) Ltd.
4. Murray et all. Medical microbiology, Elsevier
Saunders, 7th edition.
51. 5.Dr.T.V.Rao MD in 2012 about Group A
streptococcus pyogenes.
6.Dr.M.Malathi Postgraduate final year
Department of Microbiology Chengalpattu
Medical College about classifications of
streptococcus.
7.Mrs. Jincy Ealias M.Sc. (N) Asst. Professor
8.Mr. Binu Babu MBA, M.Sc. (N) Asst. Professor