Opportunistic Mycosis are: caused by fungi that cannot infect healthy humans but can
cause serious often fatal mycoses in people whose resistance has been lowered (immunocompromised patients).
Many fungi previously considered non- pathogenic are
now recognized as etiological agents of the
opportunistic fungal infections.
The laboratory must identify and report completely
the presence of all fungi recovered from
immunocompromised patient, since every organism is
a potential pathogen
The highly susceptible groups for opportunistic fungal
infection are
- AIDs patients,
-Leukemic patients,
-individuals on chemotherapy for treatment of cancer,
-alcoholics. The commonest causes of opportunistic mycosis are:
-Candidiasis
- Aspergillosis
- Zygomycosis
-Cryptococosis
-Pneumocystis carn
Candidiasis is a relatively common human infection that can
take form of;
superficial,
mucocutanous or
systemic disease.
Principally it is caused by the three species of the genus candida,
namely,
C.albicans,
C.tropicalis and
C.krusei
Superficial and mucocutaneous candidiasis
It is superficial infections of skin and mucous membranes
Through, oral and vaginal candidiasis
- Oesophageal candidiasis
-Skin lesions of folds, groin, axilla, and interdigital areas
- Napkin eruptions in infants
- Paranychial candidiaiasis
Invasive:
Candidemia: initial stage can be transient if phagocytic
system is intact.
Disseminated or hematogenous candidiasis if phagocytic
system is compromised.
Multi organs can be involved with infection: kidney,
prosthetic heart valves, brain, eye, meninges.
Mortality: 30-40%
Predisposing factors
Diabetes
Immunosupperession
T-cell immunodeficiency disorders
Acquired- immunodeficiency syndrome, (AIDS)
Leukaemias, Lymphomas
Steroid treatments
Broad spectrum antibiotics
Laboratory diagnosis
Superficial or mucocutaneous candidiasis is diagnosed by
finding the fungus in tissue scraping and culture
Systemic candidiasis is difficult to diagnose.
Definitive diagnosis is made by the histopathologic
demonstration of the invasion of tissue by the yeast.
Specimens from surface lesions, mouth, vaginal, sputum,
exudates etc are examined using different methods.
Direct examination
a) KOH
Exposed lesions can usually be easily diagnosed by
clinical appearance together with finding typical budding
yeast cells and pseudohyphae and /or true hyphea in lesion
scrapings treated with KOH.
b) Gram-stain
Gram stain smears show large gram-positive budding yeast cells
with pseudohyphea.
Germ tube test
Candida albicans can be presumptively identified based
on the production of a germ tube
Principle
When incubated with serum at 370C for 1 to 3 hours,
C.albicans will form a germ tube.
Procedure
1. Pipette 0.5 ml of serum into a test tube
2. Inoculate the tube with a small amount of the
organism to be
tested.
Opportunistic Mycosis are: caused by fungi that cannot infect healthy humans but can
cause serious often fatal mycoses in people whose resistance has been lowered (immunocompromised patients).
Many fungi previously considered non- pathogenic are
now recognized as etiological agents of the
opportunistic fungal infections.
The laboratory must identify and report completely
the presence of all fungi recovered from
immunocompromised patient, since every organism is
a potential pathogen
The highly susceptible groups for opportunistic fungal
infection are
- AIDs patients,
-Leukemic patients,
-individuals on chemotherapy for treatment of cancer,
-alcoholics. The commonest causes of opportunistic mycosis are:
-Candidiasis
- Aspergillosis
- Zygomycosis
-Cryptococosis
-Pneumocystis carn
Candidiasis is a relatively common human infection that can
take form of;
superficial,
mucocutanous or
systemic disease.
Principally it is caused by the three species of the genus candida,
namely,
C.albicans,
C.tropicalis and
C.krusei
Superficial and mucocutaneous candidiasis
It is superficial infections of skin and mucous membranes
Through, oral and vaginal candidiasis
- Oesophageal candidiasis
-Skin lesions of folds, groin, axilla, and interdigital areas
- Napkin eruptions in infants
- Paranychial candidiaiasis
Invasive:
Candidemia: initial stage can be transient if phagocytic
system is intact.
Disseminated or hematogenous candidiasis if phagocytic
system is compromised.
Multi organs can be involved with infection: kidney,
prosthetic heart valves, brain, eye, meninges.
Mortality: 30-40%
Predisposing factors
Diabetes
Immunosupperession
T-cell immunodeficiency disorders
Acquired- immunodeficiency syndrome, (AIDS)
Leukaemias, Lymphomas
Steroid treatments
Broad spectrum antibiotics
Laboratory diagnosis
Superficial or mucocutaneous candidiasis is diagnosed by
finding the fungus in tissue scraping and culture
Systemic candidiasis is difficult to diagnose.
Definitive diagnosis is made by the histopathologic
demonstration of the invasion of tissue by the yeast.
Specimens from surface lesions, mouth, vaginal, sputum,
exudates etc are examined using different methods.
Direct examination
a) KOH
Exposed lesions can usually be easily diagnosed by
clinical appearance together with finding typical budding
yeast cells and pseudohyphae and /or true hyphea in lesion
scrapings treated with KOH.
b) Gram-stain
Gram stain smears show large gram-positive budding yeast cells
with pseudohyphea.
Germ tube test
Candida albicans can be presumptively identified based
on the production of a germ tube
Principle
When incubated with serum at 370C for 1 to 3 hours,
C.albicans will form a germ tube.
Procedure
1. Pipette 0.5 ml of serum into a test tube
2. Inoculate the tube with a small amount of the
organism to be
tested.
Myself Dr. Manish Tiwari Tutor Department of microbiology at saraswati medical college and research center( unnao) making presentation is only for MBBS and MD students.
Myself Dr. Manish Tiwari Tutor Department of microbiology at saraswati medical college and research center( unnao) making presentation is only for MBBS and MD students.
This presentation cover brief discussion of morphological features, cultural characteristics, virulence factors, pathogenesis, epidemiology and lab diagnosis of staphylococcus aureus .
#MedicalMicrobiology
Lecture-1 Introduction to microbiology updated.pptxRashaAlNagar
Microaspiration from nasopharynx: S. Pneumonia
Inhalation: TB, viruses, Legionella
Aspiration: anaerobes
Bloodborne: Staph endocarditis, septic emboli
Direct extension: trauma
Microaspiration from nasopharynx: S. Pneumonia
Inhalation: TB, viruses, Legionella
Aspiration: anaerobes
Bloodborne: Staph endocarditis, septic emboli
Direct extension: trauma
Microaspiration from nasopharynx: S. Pneumonia
Inhalation: TB, viruses, Legionella
Aspiration: anaerobes
Bloodborne: Staph endocarditis, septic emboli
Direct extension: trauma
Microaspiration from nasopharynx: S. Pneumonia
Inhalation: TB, viruses, Legionella
Aspiration: anaerobes
Bloodborne: Staph endocarditis, septic emboli
Direct extension: trauma
Microaspiration from nasopharynx: S. Pneumonia
Inhalation: TB, viruses, Legionella
Aspiration: anaerobes
Bloodborne: Staph endocarditis, septic emboli
Direct extension: trauma
CAP usually caused by a single organism
Even with extensive diagnostic testing, most investigators cannot identify a specific etiology for CAP in ≥ 50% of patients.
Caused by a variety of Bacteria, Viruses, Fungi
Streptococcus pneumoniae is the most common pathogen 60-70% of the time
one of the bacteria named staphylococcus which causes infection in human, from mild to severe.
It is useful for all medical students and paramedical students.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
263778731218 Abortion Clinic /Pills In Harare ,sisternakatoto
263778731218 Abortion Clinic /Pills In Harare ,ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group ABORTION WOMEN’S CLINIC +27730423979 IN women clinic we believe that every woman should be able to make choices in her pregnancy. Our job is to provide compassionate care, safety,affordable and confidential services. That’s why we have won the trust from all generations of women all over the world. we use non surgical method(Abortion pills) to terminate…Dr.LISA +27730423979women Clinic is committed to providing the highest quality of obstetrical and gynecological care to women of all ages. Our dedicated staff aim to treat each patient and her health concerns with compassion and respect.Our dedicated group of receptionists, nurses, and physicians have worked together as a teamof receptionists, nurses, and physicians have worked together as a team wwww.lisywomensclinic.co.za/
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
Contact us if you are interested:
Email / Skype : kefaya1771@gmail.com
Threema: PXHY5PDH
New BATCH Ku !!! MUCH IN DEMAND FAST SALE EVERY BATCH HAPPY GOOD EFFECT BIG BATCH !
Contact me on Threema or skype to start big business!!
Hot-sale products:
NEW HOT EUTYLONE WHITE CRYSTAL!!
5cl-adba precursor (semi finished )
5cl-adba raw materials
ADBB precursor (semi finished )
ADBB raw materials
APVP powder
5fadb/4f-adb
Jwh018 / Jwh210
Eutylone crystal
Protonitazene (hydrochloride) CAS: 119276-01-6
Flubrotizolam CAS: 57801-95-3
Metonitazene CAS: 14680-51-4
Payment terms: Western Union,MoneyGram,Bitcoin or USDT.
Deliver Time: Usually 7-15days
Shipping method: FedEx, TNT, DHL,UPS etc.Our deliveries are 100% safe, fast, reliable and discreet.
Samples will be sent for your evaluation!If you are interested in, please contact me, let's talk details.
We specializes in exporting high quality Research chemical, medical intermediate, Pharmaceutical chemicals and so on. Products are exported to USA, Canada, France, Korea, Japan,Russia, Southeast Asia and other countries.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
3.
Staphylococci are gram positive cocci,
Occur in grape like clusters,
First observed by Von Recklinghausen(1871) in human
pyogenic lesions
Pasteur(1880) obtained liquid culture from pus and
produced abscesses by inoculating them into rabbits
Sir Alexender Ogston gave it the name
“STAPHYLOCOCCUS”
In Greek; staphyle - Bunch of grapes
Kokkus - Berry
Introduction & History
4.
5. Staphylococci strain from:
Pyogenic lesions: produce golden yellow colonies (S
.aureus)
Normal skin: white colonies (S.albus)
S.citreus: lemon yellow colonies
Human skin:
coagulase negative staphylococcus
S.aureus :lesser extent
Prefered habitat:anterior nares (40%adults carriers)
Micrococci :in skin and in environment
Stomatococcus(s.mucilaginosus):normal human oral flora
Contd…
6.
Species of Staphylococci found in human skin:
S.saprophyticus
S.epidermidis
S.haemolyticus
S.hominis
S.warneri
S.lugdunensis
S.simulans
S.xylosus
Contd…
8. Culture:
Media used :-
i) Non selective media: Nutrient agar,
Blood agar,
MacConkey’s agar.
ii) Selective media: Salt-milk agar,
Ludlam’s medium
Robertson’s cooked meat medium with 10% sodium
chloride
Temperature range :10°C - 42°C (optimum temp: 37°C)
pH:7.4-7.6
Aerobes & facultative anaerobes
Culture characteristics:
9. Culture
characteristics:
i) On nutrient agar: The
colonies are :
large circular,
convex,
smooth,
shiny,
opaque and
Easily emulsifiable.
Most strains produce
golden yellow pigments.
10. ii) On MacConkey’s agar- The colonies are small & pink in
colour. (due to lactose fermentation)
iii) On blood agar- Most strains produce β- haemolytic
colonies. (specially incubated under 20-25%
carbondioxide)
iv) On liquid medium: uniform urbidity is produced
13. Contd….
3) Reduces nitrate to nitrite.
4) Ferments mannitol anaerobically with acid only.
5) Urea hydrolysis test- Positive.
6) Gelatin liquefaction test- Positive.
7) Produces Lipase.
8) Produces Phosphatase.
9) Produces Thermostable nuclease.
10) MR & VP positive
11) Indole negative
12) Bacitracin resistant
13)Grow on agar that contains peptone
15)Some are ß-hemolytic
14. Staphylococci are among the more resistant non-spore
forming bacteria
Remain viable for 3-6 months (have been isolated from dried
pus after 2-3 months
May withstand 60°C for 30 minutes (thermal death
time:62°C for 30 minutes)
some Staphylococci require heating at 80°C for 1 hour to
be killed
Heat resistant strains have ability to grow in higher
temperature even at 45°C
Resist 1 % phenol for 15 mins.
Mercury peroxide 1% solution can kill them in 10 mins.
Resistance :
15. Penicillin resistance
3 types:
Production of Beta lactamase
Alteration in penicillin binding protein PBP2a
Development of tolerance to penicillin
Bacterium is only inhibited but not killed
16. Contd…
Production of beta lactamase:(penicillinase)
Inactivates penicillin
Staphylococci produces 4 types of penicillinases(A-D)
Hospital strains:type A penicillinase
Penicillinase:
inducible enzyme
Production usually controlled by plasmids,which are
transmitted by transduction or conjugation
Same plasmid: may carry genes for resistance to a range
of other antibiotics and heavy metals
17. Alteration in penicillin binding protein(PBP2a) &
changes in bacterial surface receptors:
reduces binding of beta lactam antibiotics to cells
Normally chromosomal in nature
Expressed more at 30°C than at 37°C
Also extends to cover beta lactamase-resistant
penicillins such as methicillin and cloxacillins (MRSA)
EMRSA:’epidemic methicillin-resistant Staphylococcus
aureus’
erythromycins,tetracyclines,aminoglycosides and heavy
metals
Contd…
18. PATHOGENICITY:
Source of infection:
A) Exogenous: patients or carriers
B) Endogenous: From colonized site
Mode of transmission:
A) Contact: direct or indirect( through fomites)
B) Inhalation of air borne droplets
Pathogenicity and virulence
20. A) CELL ASSOCIATED FACTORS:
a) Cell associated polymers
b) Cell surface proteins
a) CELL ASSOCIATED POLYMERS
1. Cell wall polysaccharide
2. Teichoic acid
3. Capsular polysaccharide
b) CELL SURFACE PROTEINS:
1. Protein A
2. Clumping factor (bound coagulase)
21.
Protein A:present in cell wall of most S.aureus
Strains
Chemotactic
Anti-phagocytic:
Binds to Fc part of IgG
Blocks phagocytosis
Anti-complementary
Induces platelet damage and hypersensitivity
22. B) EXTRACELLULAR FACTORS
a) Enzymes:
1. Free coagulase
2. Catalase
3. Lipase(infect skin and subcuaneous tissues)
4. Hyaluronidase(hydrolyse hyaluronic acid in
connective tissues)
5. DNAase
6. Thermonuclease
7. Staphylokinase (Fibrinolysin)
8. Phosphatase
23. Contd…
b) Toxins:
1.Cytolytic toxins(membrane active substance)
(affects RBC and WBC)
i) Haemolysins
Alpha haemolysin(paradoxic):toxic to
macrophages,lysosomes,muscle tissues,renal cortex and
circulatory system
Beta haemolysin (sphingomyelinase)
Shows hot-cold phenomena
Gamma haemolysin
Delta haemolysin:
detergent like effects on cell membreane of
erythrocytes,leucocytes,macrophages and platelets
ii) Leucocidin (Panton-Valentine toxin)
26. A) INFECTIONS:
Mechanism of pathogenesis:
Cocci gain access to damaged skin, mucosal or
tissue site
Colonize by adhering to cells or extracellular matrix
Evade the host defense mechanisms and multiply
Cause tissue damage
27. Common Staphylococcal infections:
1) Skin and soft tissue: Folliculitis, furuncle (boil), carbuncle,
styes, abscess, wound infections, impetigo, paronychia and
less often cellulitis.
Folliculitis
Furuncle (boil)
Folliculitis
32. B) INTOXICATIOINS:
The disease is caused by the bacterial exotoxins,
which are produced either in the infected host
or preformed in vitro.
There are 3 types-
1. Food poisoning
2. Toxic shock syndrome
3. Staphylococcal scalded skin syndrome
33. 1) Food poisoning: (Enterotoxin)
Enterotoxin is responsible for manifestations of staphylococcal food
poisoning.
Eight types of enterotoxin are currently known, named A, B, C1-3, D,
E, and H.
It usually occurs when preformed toxin is ingested with contaminated
food.
The toxin acts directly on the autonomic nervous system to cause the
illness, rather than gut mucosa.
34.
The common food items responsible are - milk and
milk products, meat, fish and ice cream.
Source of infection- food handler who is a carrier.
Incubation period- 2 to 6 hours.
Clinical symptoms- nausea, vomiting and diarrhoea.
The illness is usually self limited, with recovery in a
day or so.
Contd…
35. 2) Staphylococcal Toxic shock syndrome (STSS):
STSS is associated with infection of mucosal or sequestered
sites by TSST( formerly known as enterotoxin type F)
producing S.aureus.
It is fatal multisystem disease presenting with fever,
hypotension, myalgia, vomiting, diarrhoea, mucosal
hyperemia and erythematous rash which desquamates
subsequently.
36. 2 types of STSS known:
i) Menstrual associated STSS: Here colonization of
S.aureus occurs in the vagina of menstruating
woman who uses highly absorbent vaginal tampons.
ii) Non menstrual associated STSS: Here colonization of
S.aureus occurs in other sites like surgical wound.
37. 3) Staphylococcal scalded skin syndrome
(SSSS):
Exfoliative toxin produced by S.aureus is responsible
for this.
It is a skin disease in which outer layer of epidermis
gets separated from the underlying tissues.
38. Types of SSSS:
Severe form Milder form
In new born - Ritter’s disease - Pemphigus
neonatorum
In older patients - Toxic epidermal - Bullous
necrolysis impetigo
40. LAB DIAGNOSIS:
1.Specimens: Depends on the type of infection.
Suppurative lesion- Pus,
Respiratory infection- Sputum,
Bacteremia & septicemia- Blood,
Food poisoning- Feces, vomit & the remains of suspected
food,
For the detection of carriers- Nasal swab.
41. 2.microscopy:
Direct microscopy with Gram stained smear is useful in
case of pus, where cocci in clusters are seen.
This is of no value for specimen like sputum where
mixed flora are normally present.
42. 3.Culture:
Specimens plated in blood agar
Staphylococcal colonies appear after overnight incubation
Specimens where staphylococci are expected to be scanty and
outnumbered by other bacteria are inoculated on selective
media
Salt-milk agar,
Ludlam’s medium
Robertson’s cooked meat medium with 10% sodium
43. 1.Gram staining:
Smears are examined from the culture plate and reveals Gram
positive cocci(1μm in diameter) arranged in grape like clusters.
3.Identification:
44. Differentiation between staphylococci micrococci and
stomatococci
property staphylococcus micrococcus stomatococcus
Anaerobic growth + _ +
Carbohydrate utilization F O F
catalase + + Weak
oxidase _ + _
Bacitracin R S S
lysostaphin S R R
Adherence to agar _ _ +
45.
Differentiation of S.aureus from CONS
Contd…
test S.aureus S.epidermidis S.saprophyticus
Growth on manitol salt agar + _ _
Colonial pigmentation Golden yellow white White
Coagulase test + _ _
DNAase Test + _ _
Hemolysis in blood agar beta _ _
Novobiosin sensitivity S S R
46.
Staphylococci are primary parasites of human beings and
animals.
Hospital infections caused by staphylococci deserve
special attention because of their frequency & they are
caused by strains resistant to various antibiotics.
Staphylococci are the common cause of postoperative
wound infection and other hospital cross infections.
Epidemiology:
47.
Methicillin-Resistant Staphylococcus Aureus
Epidemic strains of these; MRSA are usually
resistant to several other antibiotics
Characteristic of MRSA is its ability to thrive in
presence of penicillin like antibiotics which normally
prevent bacterial growth by inhibiting cell-wall
synthesis.
MRSA
48.
Methicillin-resistant Staphylococcus aureus
(MRSA)
Mechanism
MRSA contains the mecA gene which is responsible for the production of
an altered plasma (cell) membrane-bound enzyme, penicillin-binding
protein 2a (PBP- 2a.) , penicillin-binding protein 2’
Penicillin-binding proteins are enzymes that participate in the production
of a major component of the bacterial cell wall
The altered PBP 2a while able to perform its cell-wall synthesis function,
has a low affinity for and does not bind to beta-lactam antibiotics
mecA, stops β-lactam antibiotics from inactivating the enzymes (trans-peptidases) critical for
cell wall synthesis.
49.
Methicillin-resistant Staphylococcus aureus
(MRSA)
Thus, the presence of the mecA gene confers resistance to all beta-
lactam antibiotics such as methicillin.
The mec A gene along with several other virulence and/or antibiotic
resistance genes is carried on a movable segment or unit of the
bacterium’s chromosome called the “staphylococcal cassette
chromosome mec ” (SCCmec).
Currently, there are 6 different types; I, II, III, IV, V and VI, and all
of which vary in size
The larger the SCCmec type, the more room there is for resistance
and other genes
Hospital-acquired MRSA strains usually contain types I, II, or III,
while community-associated MRSA strains contain types IV, and V.
Mechanism
51.
Treatment
Methicillin-resistant Staphylococcus aureus
(MRSA)
Both CA-MRSA and HA-MRSA are resistant to
traditional anti-staphylococcal beta-lactam antibiotics,
such as cephalexin
CA-MRSA has a greater spectrum of antimicrobial
susceptibility to sulfa drugs (like co-trimoxazole
(trimethoprim/sulfamethoxazole), tetracyclines (like do
xycycline and minocycline)
and clindamycin (for osteomyelitis)
MRSA can be eradicated with a regimen of linezolid,
though treatment protocols vary and serum levels of
antibiotics vary widely person to person and may affect
outcomes
52.
Linezolid belongs to the newer oxazolidinone
class of antibiotics which has been shown to be
effective against both CA-MRSA and HA-
MRSA.
The effective treatment of MRSA with linezolid has been successful in 87% of
people. Linezolid is more effective in soft tissue infections than vancomycin. This is
compared to eradication of infection in those with MRSA treated with vancomycin.
Treatment with vancomycin is successful in approximately 49% of people
The Infectious Disease Society of America recommends
vancomycin, linezolid, or clindamycin (if susceptible) for treating
those with MRSA pneumonia.
Methicillin-resistant Staphylococcus aureus
(MRSA)
53.
Methicillin-resistant Staphylococcus aureus
(MRSA)
Treatment
Vancomycin remains the drug of choice for treatment of infections caused
by MRSA, although it is intrinsically less active than the antistaphylococcal
penicillins
Combinations of vancomycin with beta-lactam antibiotics may be
synergistic in vivo against MRSA strains, including those with intermediate
susceptibility to vancomycin
Given the increasing prevalence of MRSA in hospitals and in community
settings, alternative approaches are needed for treatment of infections
caused by MRSA.
54.
Methicillin-resistant Staphylococcus aureus
(MRSA)
Treatment
Vancomycin
and teicoplanin are glycopeptide antibiotics
used to treat MRSA infections
Teicoplanin is a structural congener of
vancomycin that has a similar activity
spectrum but a longer half-life
Because the oral absorption of vancomycin
and teicoplanin is very low, these agents can
be administered intravenously to control
systemic infections.
56. PREVENTION:
Isolation & treatment of MRSA
patients.
Detection of carriers among hospital
staff, their isolation & treatment.
Avoid indiscriminate usage of
antibiotics.
Following strict aseptic technique
Hand washing,oldest simplest and
most effective method of previnting
hospital cross-infection.
57. Other coagulase positive Staphylococci:
Staphylococcus aureus subsp. Anaerobius
S. a. aureus
S. hyicus
S. intermedius and
Staphylococcus schleiferi subsp. coagulans.
58. Coagulase Negative Staphylococci( CoNS ):
Two species of coagulase negative
Staphylococci can cause human infections-
1. Staphylococcus epidermidis
2. Staphylococcus saprophyticus
59. S. Epidermidis:
It is a common cause of stitch abscesses.
It has predilection for growth on implanted foreign bodies such
as artificial valves, shunts, intravascular catheters and
prosthetic appliances leading to bacteraemia.
In persons with structural abnormalities of urinary tract, it can
cause cystitis.
Endocarditis may be caused, particularly in drug addicts.
60. S.saprophyticus:
It causes urinary tract infections, mostly in sexually active
young women.
The infection is symptomatic and may involve the upper
urinary tract also.
Men are infected much less often.
It is one of the few frequently isolated CoNS that is resistant
to Novobiocin
61. Other coagulase negative staphylococci:
S.haemolyticus
S. saprophyticus
S. warneri,
S.hominis,
S.epidermidis
S. caprae and
S.lugdunensis