SlideShare une entreprise Scribd logo
1  sur  66
Télécharger pour lire hors ligne
Microbiology
Bacteria, Viruses and Yeast/Fungi
…and some drugs and stuff
Sarah Watson, 2010
Bacteria
Pathogenicity Factors
1. Adherence factors
Allow adherence to body surfaces
2. Invasins
Promote tissue invasion
3. Endotoxins/exotoxins
Cause the damage!
4. Factors that confer ability to evade immune
response
= virulence factors
= how bacteria cause disease
Which cause disease?
1. Classics
E.g. Mycobacterium tuberculosis
2. Commensals
E.g. Escherichia coli
3. Opportunists
E.g. Pneumocystis jiroveci
Gram Staining
Blue-black/violet Pink/red
Gram Positive
Bacilli
• Clostridium
– botulinum
– difficile
– perfringens
– tetani, etc.
• Bacillus
– anthracis (anthrax)
– cereus
• Listeria monocytogenes
• Actinobacteria
• Enterococcus
• Lactobacillus
• Mycobacterium
Cocci
• Staphylococcus aureus
• Streptococcus
– Group A: pyogenes
– Group B: agalactiae
– pneumoniae (diplococci);
α-haemolytic
β-haemolytic
Gram Positive Bacilli
Clostridium difficile
Gram Positive Cocci
Stapylococcus aureus
Streptococcus pyogenes
Streptococcus pneumoniae
Clostridium
• Food poisoning (C.
perfringens)
• Diarrhoea (C. diff.)
• Botulism (C. botulinum)
• Tetanus (C. tetani)
• Sepsis of unknown source
Listeria monocytogenes
• Gastroenteritis
Bacillus anthracis
• Causes anthrax
• 3 types:
– Cutaneous
• Localised inflammatory black necrotic lesion (eschar)
• If leads to systemic infection, can be fatal
– Pulmonary
• Massive oedema and shock (pretty fatal)
– Gastrointestinal
• Anorexia, nausea, vomiting, abdo pain, haemorrhagic
diarrhoea
• Can be fatal
Staph. aureus (MSSA/MRSA)
• Cellulitis
• Venous leg ulcer
• Infected cannulation site
• HAP (MRSA)
• Sepsis of unknown source
Strep.
• Cellulitis
• Necrotizing fasciitis
• Venous leg ulcers
• Acute otitis media (Strep. pneumoniae)
• Pharyngitis (Strep. pyogenes)
• CAP (Strep. pneumoniae)
• Cystitis (Strep. agalactiae)
Strep. pyogenes
Gram Negative
Bacilli
• Campylobacter jejuni
• ‘Coliforms’
• Escherichia coli
• Helicobacter pylori
• Klebsiella spp.
– pneumoniae
• Legionella pneumophila
• Proteus spp.
• Pseudomonas aeruginosa
• Salmonella spp.
– typhi
– enteriditis
• Shigella spp.
• Treponema pallidum
• Enterobacter
• Vibrio cholerae
Cocci
• Neisseria (diplococci)
– gonorrhoeae
– meningitidis
Coccobacilli
• Haemophilus influenzae
Others
• Gardnerella vaginalis
(variable)
• Mycobacterium tuberculosis
(AAFB)
Gram Negative Bacilli
E. coli
H. pylori
Gram Negative Bacilli (contd.)
Pseudomonas aeruginosa Salmonella typhi
Gram Negative Cocci
Neisseria meningitidis
Gram Negative Coccobacilli
Haemophilus influenzae
Mycobacterium tuberculosis
• Campylobacter jejuni/enteritis
– Diarrhoea
• ‘Coliforms’ (inc. ESBLs)
– HAP
– Cystitis
– Pyelonephritis
– Abdominal sepsis
– Sepsis of unknown source
• Escherichia coli
– Cystitis
– Pyelonephritis
– Diarrhoea
• Helicobacter pylori
– Peptic ulcers
– Ca stomach
• Klebsiella pneumoniae
– CAP/HAP
• Legionella pneumophila
– CAP
• Proteus spp.
– Cystitis
– Pyelonephritis
• Pseudomonas aeruginosa
– HAP
• Salmonella spp.
– Typhi (typhoid)
– Enteriditis (diarrhoea)
• Shigella spp.
– Diarrhoea
• Treponema pallidum
– Syphilis
• N. gonorrhoeae
– Gonorrhoea
– Vaginal discharge
– Urethritis
– PID
• N. meningitidis
– Meningitis
– Sepsis of unknown
source
• Haemophilus infleunzae
– Acute otitis media
– Community acquired
pneumonia (CAP)
• Gardnerella vaginalis
– Vaginal discharge
– Bacterial vaginosis
– Vaginitis
• Mycobacterium
tuberculosis
– TB
Meningitis – common causative
organisms
• Neonates
– Streptococcus pneumoniae
(pneumococcal meningitis)
– Escherichia coli
– Listeria monocytogenes
• Older infants/children
– Streptococcus pneumoniae
– Neisseria meningitidis
(meningococcal meningitis)
– Haemophilus influenzae
• Adults
– Streptococcus pneumoniae
– Neisseria meningitidis
• Older adults (>50)
– Listeria monocytogenes
• Pregnancy
– Listeria monocytogenes
• Vaccinations against the top
3 (Strep, Neiss & Haemoph)
exist and have led to a
decline in cases
NB: 3 most common = NHS
Neisseria, Haemophilus,
Streptococcus
Gram Null
• Chlamydia trachomatis
• Chlamydophila pneumoniae (Chlamydia)
Elementary body
Reticulate body
Summary – Bacteria Types
Gram +ve
• Coccus
– Staph and Strep
• Bacillus
– Clostridium
– Listeria
– (anthracis)
Gram -ve
• Coccus
– Neisseria
• Cocco-bacillus
– Haemophilus
Everything else we need to know is Gram –ve bacillus,
except Mycobacterium tuberculosis & Gardnerella vaginalis
(plus the couple of Gram null ones).
Antibiotics - types
• Penicillins
– Inc. co-amoxiclav
• Cephalosporins
– Cefotaxime
– Ceftriaxone
– Cefalexin
• Macrolides
– Clarithromycin
– Erythromycin
• Aminoglycosides
– Gentamicin
• Quinolones
– Ciprofloxacin
• Sulphonamides
– Septrin (co-trimoxazole)
– Trimethoprim
• Tetracyclines
– Doxycycline
– Tetracycline
• Others
– Chloramphenicol
– Metronidazole
– Vancomycin
Penicillins
• Bacteriocidal
• β-lactam (ring) activity
– Inhibits peptidoglycan cross-linking
• Usually active against Gram +ve orgs (e.g. penicillin,
flucloxacillin, amoxicillin; co-amoxiclav broader spectrum)
• Penicillin G – IV (benzylpenicillin sodium)
• Penicillin V – oral (phenoxymethylpenicillin)
• Benzathine benzylpenicillin – IM (special order: syphilis)
Cephalosporins
• Bacteriocidal
• β-lactam activity
• Less susceptible to penicillinases
• Broad spectrum
• E.g. ceftriaxone, cefotaxime (3rd generation)
Carbapenems
• Broad spectrum
• β-lactam ring largely resistant to β-lactamases
• E.g. meropenem, ertapenem
Macrolides
• Bacteriostatic
• Macrolide ring activity
– Binds irreversibly to 50S subunit of bacterial
ribosome; inhibits protein synthesis
• Used against Streptococci/MSSA in penicillin
allergy
• E.g. erythromycin
Aminoglycosides
• Bactericidal
• Bind irreversibly to 30S subunit of bacterial
ribosome
– Prevents elongation of polypeptide chain (tRNA)
• Good for Gram –ve aerobes
• E.g. gentamicin
Quinolones
• Bactericidal
• Bind to DNA gyrase-DNA complex
– Inhibits DNA replication
• E.g. ciprofloxacin
Sulphonomides
• Bacteriostatic
• Compete with substrate of enzyme
responsible for folic acid synthesis
• E.g. trimethoprim
Tetracyclines
• Bacteriostatic
• Prevent tRNA binding to 30S subunit
– Inhibits protein synthesis
• E.g. doxycycline
Others
• Metronidazole
(imidazole)
– Breakdown products
disrupt DNA helix; inhibits
nucleic acid synthesis
– Good for anaerobes
• Chloramphenicol
– Interferes with protein
synthesis
• Vancomycin
(glycopeptide)
– inhibits cell wall synthesis
– Gram +ve orgs
• Anti-tuberculous drugs
– Initial phase (1st 2 months)
• Rifampicin
• Isoniazid
• Pyrazinamide
• Ethambutol
– Continuation phase
(next 4months)
• Rifampicin
• Isoniazid
Antibiotics used…
• Infection by organ system
• Reference: BNF
• Highlighted in red = those we probably need
to have a grasp of
GI
• Campylobacter enteritis
– Ciprofloxacin or erythromycin
• Salmonella
– Ciprofloxacin or cefotaxime
• Shigellosis
– Ciprofloxacin. Amoxicillin or trimethoprim can be used if
organism sensitive.
• Typhoid fever
– Ciprofloxacin or cefotaxime
• Clostridium difficile infection
– Oral metronidazole or oral vancomycin
• Biliary-tract infection
– Ciprofloxacin or gentamicin or a cephalosporin
• Peritonitis
– A cephalosporin + metronidazole or gentamicin + metronidazole
or gentamicin + clindamycin or piperacillin with tazobactam
CVS
• Endocarditis initial ‘blind’ therapy
– Flucloxacillin (or benzylpenicillin if symptoms less severe) +
gentamicin
• Endocarditis caused by staphylococci
– Flucloxacillin
• Endocarditis caused by streptococci (e.g. viridans
streptococci)
– Benzylpenicillin + gentamicin
• Endocarditis caused by enterococci (e.g. Enterococcus
faecalis)
– Amoxicillin (or vancomycin if penicillin-allergic or penicillin-
resistant) + gentamicin
• Endocarditis caused by haemophilus, actinobacillus,
cardiobacterium, eikenella, and kingella species (‘HACEK’
organisms)
– Amoxicillin (or ceftriaxone if amoxicillin-resistant) + low-dose
gentamicin
RS
• Haemophilus influenzae epiglottitis
– Cefotaxime or chloramphenicol IV
• Acute exacerbations of chronic bronchitis
– Amoxicillin (or tetracycline or clarithromycin; approx. 20% H.
influenzae strains amoxicillin-resistant)
• Low or moderate-severity community-acquired pneumonia
– Amoxicillin (or doxycycline or clarithromycin)
• High-severity community-acquired pneumonia of unknown
aetiology
– Co-amoxiclav + clarithromycin
• Pneumonia possibly caused by atypical pathogens
– Clarithromycin.
• Hospital-acquired pneumonia
– Early-onset infection (less than 5 days after admission to hospital), co-
amoxiclav or cefuroxime
– Late-onset infection (more than 5 days after admission to hospital), an
antipseudomonal penicillin (e.g. piperacillin with tazobactam) or a
broad-spectrum cephalosporin (e.g. ceftazidime) or another
antipseudomonal beta-lactam or a quinolone (e.g. ciprofloxacin)
CNS
• Meningitis initial empirical therapy
– Benzylpenicillin or cefotaxime
• Meningitis caused by meningococci
– Benzylpenicillin or cefotaxime
• Meningitis caused by pneumococci
– Cefotaxime
• Meningitis caused by Haemophilus
influenzae
– Cefotaxime
• Meningitis caused by Listeria
Urinary
• Acute pyelonephritis
– A broad-spectrum cephalosporin or a quinolone
• Acute prostatitis
– Ciprofloxacin or ofloxacin or trimethoprim
• ‘Lower’ urinary-tract infection
– Trimethoprim or nitrofurantoin or amoxicillin or
oral cephalosporin (e.g. cefalexin)
Genital
• Syphilis
– Benzathine benzylpenicillin (unlicensed) or doxycycline or
erythromycin
• Uncomplicated gonorrhoea
– Ciprofloxacin. Pharyngeal infection requires ceftriaxone.
• Uncomplicated genital chlamydial infection, non-
gonococcal urethritis and non-specific genital
infection
– Azithromycin or doxycycline
• Pelvic inflammatory disease
– Doxycycline + metronidazole + i/m ceftriaxone or ofloxacin
+ metronidazole
• Bacterial vaginosis
– Oral or topical metronidazole or topical clindamycin
ENT
• Pericoronitis (infected wisdom tooth)
– Metronidazole or amoxicillin
• Acute necrotising ulcerative gingivitis
– Metronidazole or amoxicillin
• Periapical or periodontal abscess
– Amoxicillin or metronidazole
• Periodontitis
– Metronidazole or doxycycline
• Throat infections
– Phenoxymethylpenicillin (or clarithromycin if penicillin-allergic)
• Sinusitis
– Amoxicillin or doxycycline or clarithromycin
• Otitis externa
– Flucloxacillin or clarithromycin
• Otitis media
– Amoxicillin (or clarithromycin if penicillin-allergic)
Eye
• Purulent conjunctivitis
– Chloramphenicol or gentamicin eye drops
Skin
• Impetigo (superficial infection, Staph. aureus/Strep. pyogenes)
– Topical fusidic acid (or mupirocin if methicillin-
resistant Staph. aureus)
• Erysipelas (Strep. pyogenes commonly  inflamed dermis)
– Phenoxymethylpenicillin (or clarithromycin if
penicillin-allergic)
• Cellulitis
– Benzylpenicillin + flucloxacillin (or clarithromycin
alone if penicillin allergic)
• Animal and human bites
– Co-amoxiclav
M/S
• Osteomyelitis
– Flucloxacillin or clindamycin if penicillin-allergic (or
vancomycin if resistant Staph. epidermidis or
metihcillin-resistant Staph. aureus)
• Septic arthritis
– Flucloxacillin or clindamycin if penicillin-allergic (or
vancomycin if resistant Staph. epidermidis or
methicillin-resistant Staph. aureus); cefotaxime if
gonococcal arthritis or Gram-negative infection
Antibiotic Resistance
How?
• Natural
selection/environmental
stresses (point mutations)
• Horizontal gene transfer
– Plasmid transferred via
conjugation pilus (~sex)
Why?
• Poor hand hygiene spreads
resistant orgs
• Poor compliance (sub-
optimal concentrations)
• Prescribed unnecessarily
Antibiotic Resistance
• Some examples:
– Meticillin-resistant Staphylococcus aureus (MRSA)
• Wounds; ulcers; IV lines; abscesses…bacteraemia/septicaemia
• Vancomycin/gentamicin
• Trimethoprim/nitrofurantoin if UTI
– Clostridium difficile
• Diarrhoea…colitis…perforation/peritonitis
• Vancomycin
– Penicillin-resistant Streptococcus pneumoniae
– Vancomycin-resistant enterococci
– Multi-resistant salmonellae
– Multi-resistant Mycobacterium tuberculosis
• Streptomycin
• Rx guided by sensitivity of infecting strain (BNF, 2009)
(WHO)
Eukaryotes
• Candida albicans
• Cryptosporidium parvum
• Entamoeba histolytica
• Giardia intestinalis
• Pneumocystis jiroveci
• Trichomonas vaginalis
Candida albicans
• Yeast  Candidiasis:
– Cutaneous, GU, GI, resp. tract, systemic…
• Opportunistic
• Disease relates primarily to host immune state
• Rx:
– Topical e.g. clotrimazole
– Oral e.g. fluconazole
Cryptosporidium parvum
• Protozoan  Cryptosporidiosis
– Parasitic disease of mammalian GIT
• Faeco-oral route of transmission
• Diarrhoea, abdo pain, etc.
• No therapeutic agent clearly identified as
effective
– Supportive Rx – fluids
– Paromomycin may relieve diarrhoeal symptoms
– ? new treatments
• Rx: self-limiting if immunocompetent
Entamoeba histolytica
• Anaerobic protozoan
• Amoebic dysentery
– Bloody diarrhoea
– Painful passage of stool
– Colicy abdo pain
• Amoebic abcesses of liver
– Invades through GIT wall and spreads to other
organs…
• Rx: metronidazole/tinidazole
Pneumocystis jiroveci
• Yeast-like fungus
• Common cause of
pneumonia in AIDS
• Opportunistic
• Rx: co-trimoxazole +
prophylaxis
Giardia intestinalis
• Flagellated protozoan  Giardiasis
• Common waterborne disease; soil, food.
• Faeco-oral route of transmission
• Diarrhoea/abdo pain, etc.
• Rx: metronidazole/tinidazole
Trichomonas vaginalis
• Protozoan  Trichomoniasis
• STI
– Vagina/urethra women
• Frothy yellow-green discharge with strong odour
• Dyspareunia/dysuria
• Inflammation; increased risk HIV infection
– Urethra/sometimes prostate men
• Discharge
• Irritation inside penis/dysuria
• Rx: metronidazole/tinidazole
Viruses
• EBV
• HAV
• HBV
• HCV
• HEV
• HIV
• HPV
• HSV
• VZV
• RSV
• Influenza
• Norovirus
• Rhinovirus
• Rotavirus
EBV
• Epstein Barr Virus = Human Herpes Virus 4
(HHV4)
• Cold symptoms  infectious mononucleosis
• Fatigue, fever, sore throat, lymphadenopathy
• Risk if rupturing spleen so no sports for 1/12!
• Acetaminophen/NSAIDs to help fever/pain
• Normally remains in WBCs for life
• Ca risk if prolonged infection
• ? vaccines
Hepatitis – HAV/HBV/HBC/HEV
• See lecture!
HIV
• See lecture!
Human Papilloma Virus - HPV
• Low risk – genital warts (STI)/skin warts
• High risk: Ca cervix, vagina, vulva, anus, penis
• Respiratory papillomatosis
• Untreatable; usually clears spontaneously
– Can treat the warts
• Vaccines: Cervarix, Gardasil
Herpes Simplex Virus - HSV
• = Human Herpes Virus (1 &2)
• Types:
– Orofacial herpes (most common), i.e. herpes labialis (cold sores)
– Genital herpes
– Herpes whitlow (hands)
– Ocular herpes (eyes)
– Herpes encephalitis (brain)…+ others!
• Watery blisters in skin/mucus membranes
• Lies latent in nerve cell bodies; outbreaks
• No cure per se
– ? vaccines under development
– Antivirals e.g. aciclovir cream
– Analgesia
– Anaesthesia (e.g. topical lignocaine)
Varicella Zoster Virus - VZV
• = Human Herpes Virus 3
• Fluid-filled blisters surrounded by reddened skin
• General malaise, sore throat, headache, etc.
• Rx:
– Topical antivirals e.g. aciclovir
– Ig for at risk individuals (neonates, pregnant, etc)
– Vaccine in seronegative/at risk individuals
• Varilrix/Varivax
– Pain management post shingles
Respiratory Syncitial Virus - RSV
• Common cause of bronchiolitis/viral pneumonia
in kids (< 6/12 mostly);
• Older children/adults get a cold (limited to URT)
• Rx:
– Paracetamol/ibuprofen
– Ribavirin
• Inhibits range of DNA/RNA viruses
– Palivizumab
• Monoclonal Ab
• Prevents serious LRTI in kids at risk
Influenza
• Oseltamivir and
zanamivir as post-
exposure prophylaxis
– Inhibit neuraminidase
• Vaccines
– Seasonal
• High risk individuals
– Pandemic
• Pandemrix/Celvapan for
swine ‘flu
• See lecture notes
Norovirus
• Winter vomiting bug; RNA virus
• Most common cause of gastroenteritis in UK
– D&V, fever, etc.
• Faeco-oral route/contaminated food & water
• Rx:
– Stay at home
– Paracetamol for fever symptoms
– Rehydrate!
Rotavirus
• As for norovirus…
Rhinovirus
• Causes common cold; triggers acute asthma
exacerbations
• RNA virus
• Aerosol-droplet; contaminated surfaces
• No vaccine; supportive treatment only.
Notifiable diseases!
Anthrax Ophthalmia neonatorum
Cholera Paratyphoid fever
Diphtheria Plague
Dysentery (amoebic or bacillary) Poliomyelitis, acute
Encephalitis, acute Rabies
Food poisoning Relapsing fever
Haemorrhagic fever (viral) Rubella
Hepatitis, viral Scarlet fever
Leprosy Smallpox
Leptospirosis Tetanus
Malaria Tuberculosis
Measles Typhoid fever
Meningitis Typhus
Meningococcal septicaemia (without meningitis) Whooping cough
Mumps Yellow fever
+ Consultant in Communicable Disease Control should be informed
BNF 59

Contenu connexe

Tendances

Tendances (20)

Classification of bacteria
Classification of bacteriaClassification of bacteria
Classification of bacteria
 
Types of culture media
Types of culture mediaTypes of culture media
Types of culture media
 
Bacteria
BacteriaBacteria
Bacteria
 
Viruses, structure, classification and characteristics
Viruses, structure, classification and characteristicsViruses, structure, classification and characteristics
Viruses, structure, classification and characteristics
 
History & Scope of Microbiology SMG
History &  Scope of Microbiology   SMGHistory &  Scope of Microbiology   SMG
History & Scope of Microbiology SMG
 
Neisseria
NeisseriaNeisseria
Neisseria
 
Introduction to Medical mycology
Introduction to Medical mycologyIntroduction to Medical mycology
Introduction to Medical mycology
 
Microbiology: Introduction & history
Microbiology: Introduction & historyMicrobiology: Introduction & history
Microbiology: Introduction & history
 
Medical Microbiology Laboratory (pathogenic bacteria classification)
Medical Microbiology Laboratory (pathogenic bacteria classification)Medical Microbiology Laboratory (pathogenic bacteria classification)
Medical Microbiology Laboratory (pathogenic bacteria classification)
 
Chapter 1 (microbiology) 8th edition
Chapter 1 (microbiology) 8th edition Chapter 1 (microbiology) 8th edition
Chapter 1 (microbiology) 8th edition
 
Mycology
MycologyMycology
Mycology
 
Staining techniques
Staining techniquesStaining techniques
Staining techniques
 
Lect. 1 introduction to general microbiology
Lect. 1   introduction to general microbiologyLect. 1   introduction to general microbiology
Lect. 1 introduction to general microbiology
 
General bacteriology
General bacteriology General bacteriology
General bacteriology
 
Classification & properties of fungi
Classification & properties of fungi Classification & properties of fungi
Classification & properties of fungi
 
Morphology of bacteria
Morphology of bacteriaMorphology of bacteria
Morphology of bacteria
 
Staphylococcus
StaphylococcusStaphylococcus
Staphylococcus
 
Capsule staining
Capsule stainingCapsule staining
Capsule staining
 
Scope of microbiology
Scope of microbiologyScope of microbiology
Scope of microbiology
 
Culture media
Culture media Culture media
Culture media
 

Similaire à Microbiology - bacteria, fungi, yeasts and viruses

Infectious_Diseases.pptx
Infectious_Diseases.pptxInfectious_Diseases.pptx
Infectious_Diseases.pptxKhalidAbdalaziz
 
Antibiotics DR. JAMA chep 1.pptx
Antibiotics DR. JAMA chep 1.pptxAntibiotics DR. JAMA chep 1.pptx
Antibiotics DR. JAMA chep 1.pptxNadiirMahamoud
 
Antibiotics, chemistry of penicillin, cephalosporin, tetracycline
Antibiotics, chemistry of penicillin, cephalosporin, tetracyclineAntibiotics, chemistry of penicillin, cephalosporin, tetracycline
Antibiotics, chemistry of penicillin, cephalosporin, tetracyclineDhammadipNandgaye
 
Staph epidermidis and saprophyticus
Staph epidermidis and saprophyticusStaph epidermidis and saprophyticus
Staph epidermidis and saprophyticusAmirul Huda Bhuiyan
 
1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.ppt1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.pptAfifaKhan62
 
antibioticreview.ppt
antibioticreview.pptantibioticreview.ppt
antibioticreview.pptGetahunAlega
 
1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.ppt1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.pptAfifaKhan62
 
Infectious disease flash cards by me
Infectious disease flash cards by meInfectious disease flash cards by me
Infectious disease flash cards by meDanulka Vargas-Torres
 
Cephalosporin.pptx
Cephalosporin.pptxCephalosporin.pptx
Cephalosporin.pptxmdtaieb1
 
Antibiotic classes
Antibiotic classes Antibiotic classes
Antibiotic classes Khaled Saad
 
Bacterial infections by dr maria
Bacterial infections by dr mariaBacterial infections by dr maria
Bacterial infections by dr mariadr maria saeed
 
6 beta lactum drugs dental
6  beta lactum drugs dental6  beta lactum drugs dental
6 beta lactum drugs dentalIAU Dent
 

Similaire à Microbiology - bacteria, fungi, yeasts and viruses (20)

Antibiotics
AntibioticsAntibiotics
Antibiotics
 
Antibiotics
AntibioticsAntibiotics
Antibiotics
 
Infectious_Diseases.pptx
Infectious_Diseases.pptxInfectious_Diseases.pptx
Infectious_Diseases.pptx
 
Antibiotics
AntibioticsAntibiotics
Antibiotics
 
Antibiotics DR. JAMA chep 1.pptx
Antibiotics DR. JAMA chep 1.pptxAntibiotics DR. JAMA chep 1.pptx
Antibiotics DR. JAMA chep 1.pptx
 
Antibiotics, chemistry of penicillin, cephalosporin, tetracycline
Antibiotics, chemistry of penicillin, cephalosporin, tetracyclineAntibiotics, chemistry of penicillin, cephalosporin, tetracycline
Antibiotics, chemistry of penicillin, cephalosporin, tetracycline
 
Staph epidermidis and saprophyticus
Staph epidermidis and saprophyticusStaph epidermidis and saprophyticus
Staph epidermidis and saprophyticus
 
Antibioticreview
AntibioticreviewAntibioticreview
Antibioticreview
 
1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.ppt1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.ppt
 
antibioticreview.ppt
antibioticreview.pptantibioticreview.ppt
antibioticreview.ppt
 
1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.ppt1479111839-dr.m.barak-antibioticreview.ppt
1479111839-dr.m.barak-antibioticreview.ppt
 
Streptococcus
StreptococcusStreptococcus
Streptococcus
 
Infectious disease flash cards by me
Infectious disease flash cards by meInfectious disease flash cards by me
Infectious disease flash cards by me
 
Lecture_3.ppt
Lecture_3.pptLecture_3.ppt
Lecture_3.ppt
 
Cephalosporin.pptx
Cephalosporin.pptxCephalosporin.pptx
Cephalosporin.pptx
 
Klebsiella+proteus+uti
Klebsiella+proteus+utiKlebsiella+proteus+uti
Klebsiella+proteus+uti
 
Antibiotic classes
Antibiotic classes Antibiotic classes
Antibiotic classes
 
Bacterial infections by dr maria
Bacterial infections by dr mariaBacterial infections by dr maria
Bacterial infections by dr maria
 
6 beta lactum drugs dental
6  beta lactum drugs dental6  beta lactum drugs dental
6 beta lactum drugs dental
 
Staphylococcus.pptx
Staphylococcus.pptxStaphylococcus.pptx
Staphylococcus.pptx
 

Plus de meducationdotnet

Plus de meducationdotnet (20)

No Title
No TitleNo Title
No Title
 
Spondylarthropathy
SpondylarthropathySpondylarthropathy
Spondylarthropathy
 
Diagnosing Lung cancer
Diagnosing Lung cancerDiagnosing Lung cancer
Diagnosing Lung cancer
 
Eczema Herpeticum
Eczema HerpeticumEczema Herpeticum
Eczema Herpeticum
 
The Vagus Nerve
The Vagus NerveThe Vagus Nerve
The Vagus Nerve
 
Water and sanitation and their impact on health
Water and sanitation and their impact on healthWater and sanitation and their impact on health
Water and sanitation and their impact on health
 
The ethics of electives
The ethics of electivesThe ethics of electives
The ethics of electives
 
Intro to Global Health
Intro to Global HealthIntro to Global Health
Intro to Global Health
 
WTO and Health
WTO and HealthWTO and Health
WTO and Health
 
Globalisation and Health
Globalisation and HealthGlobalisation and Health
Globalisation and Health
 
Health Care Worker Migration
Health Care Worker MigrationHealth Care Worker Migration
Health Care Worker Migration
 
International Institutions
International InstitutionsInternational Institutions
International Institutions
 
Haemochromotosis brief overview
Haemochromotosis brief overviewHaemochromotosis brief overview
Haemochromotosis brief overview
 
Ascities overview
Ascities overviewAscities overview
Ascities overview
 
Overview of the Liver
Overview of the LiverOverview of the Liver
Overview of the Liver
 
Overview of Antidepressants
Overview of AntidepressantsOverview of Antidepressants
Overview of Antidepressants
 
Gout Presentation
Gout PresentationGout Presentation
Gout Presentation
 
Review of orthopaedic services: Prepared for the Auditor General for Scotland...
Review of orthopaedic services: Prepared for the Auditor General for Scotland...Review of orthopaedic services: Prepared for the Auditor General for Scotland...
Review of orthopaedic services: Prepared for the Auditor General for Scotland...
 
Sugammadex - a revolution in anaesthesia?
Sugammadex - a revolution in anaesthesia?Sugammadex - a revolution in anaesthesia?
Sugammadex - a revolution in anaesthesia?
 
Ophthamology Revision
Ophthamology RevisionOphthamology Revision
Ophthamology Revision
 

Microbiology - bacteria, fungi, yeasts and viruses

  • 1. Microbiology Bacteria, Viruses and Yeast/Fungi …and some drugs and stuff Sarah Watson, 2010
  • 3. Pathogenicity Factors 1. Adherence factors Allow adherence to body surfaces 2. Invasins Promote tissue invasion 3. Endotoxins/exotoxins Cause the damage! 4. Factors that confer ability to evade immune response = virulence factors = how bacteria cause disease
  • 4. Which cause disease? 1. Classics E.g. Mycobacterium tuberculosis 2. Commensals E.g. Escherichia coli 3. Opportunists E.g. Pneumocystis jiroveci
  • 6. Gram Positive Bacilli • Clostridium – botulinum – difficile – perfringens – tetani, etc. • Bacillus – anthracis (anthrax) – cereus • Listeria monocytogenes • Actinobacteria • Enterococcus • Lactobacillus • Mycobacterium Cocci • Staphylococcus aureus • Streptococcus – Group A: pyogenes – Group B: agalactiae – pneumoniae (diplococci); α-haemolytic β-haemolytic
  • 8. Gram Positive Cocci Stapylococcus aureus Streptococcus pyogenes Streptococcus pneumoniae
  • 9. Clostridium • Food poisoning (C. perfringens) • Diarrhoea (C. diff.) • Botulism (C. botulinum) • Tetanus (C. tetani) • Sepsis of unknown source Listeria monocytogenes • Gastroenteritis
  • 10. Bacillus anthracis • Causes anthrax • 3 types: – Cutaneous • Localised inflammatory black necrotic lesion (eschar) • If leads to systemic infection, can be fatal – Pulmonary • Massive oedema and shock (pretty fatal) – Gastrointestinal • Anorexia, nausea, vomiting, abdo pain, haemorrhagic diarrhoea • Can be fatal
  • 11. Staph. aureus (MSSA/MRSA) • Cellulitis • Venous leg ulcer • Infected cannulation site • HAP (MRSA) • Sepsis of unknown source
  • 12. Strep. • Cellulitis • Necrotizing fasciitis • Venous leg ulcers • Acute otitis media (Strep. pneumoniae) • Pharyngitis (Strep. pyogenes) • CAP (Strep. pneumoniae) • Cystitis (Strep. agalactiae) Strep. pyogenes
  • 13. Gram Negative Bacilli • Campylobacter jejuni • ‘Coliforms’ • Escherichia coli • Helicobacter pylori • Klebsiella spp. – pneumoniae • Legionella pneumophila • Proteus spp. • Pseudomonas aeruginosa • Salmonella spp. – typhi – enteriditis • Shigella spp. • Treponema pallidum • Enterobacter • Vibrio cholerae Cocci • Neisseria (diplococci) – gonorrhoeae – meningitidis Coccobacilli • Haemophilus influenzae Others • Gardnerella vaginalis (variable) • Mycobacterium tuberculosis (AAFB)
  • 14. Gram Negative Bacilli E. coli H. pylori
  • 15. Gram Negative Bacilli (contd.) Pseudomonas aeruginosa Salmonella typhi
  • 19. • Campylobacter jejuni/enteritis – Diarrhoea • ‘Coliforms’ (inc. ESBLs) – HAP – Cystitis – Pyelonephritis – Abdominal sepsis – Sepsis of unknown source • Escherichia coli – Cystitis – Pyelonephritis – Diarrhoea • Helicobacter pylori – Peptic ulcers – Ca stomach • Klebsiella pneumoniae – CAP/HAP • Legionella pneumophila – CAP • Proteus spp. – Cystitis – Pyelonephritis • Pseudomonas aeruginosa – HAP • Salmonella spp. – Typhi (typhoid) – Enteriditis (diarrhoea) • Shigella spp. – Diarrhoea • Treponema pallidum – Syphilis
  • 20. • N. gonorrhoeae – Gonorrhoea – Vaginal discharge – Urethritis – PID • N. meningitidis – Meningitis – Sepsis of unknown source • Haemophilus infleunzae – Acute otitis media – Community acquired pneumonia (CAP) • Gardnerella vaginalis – Vaginal discharge – Bacterial vaginosis – Vaginitis • Mycobacterium tuberculosis – TB
  • 21. Meningitis – common causative organisms • Neonates – Streptococcus pneumoniae (pneumococcal meningitis) – Escherichia coli – Listeria monocytogenes • Older infants/children – Streptococcus pneumoniae – Neisseria meningitidis (meningococcal meningitis) – Haemophilus influenzae • Adults – Streptococcus pneumoniae – Neisseria meningitidis • Older adults (>50) – Listeria monocytogenes • Pregnancy – Listeria monocytogenes • Vaccinations against the top 3 (Strep, Neiss & Haemoph) exist and have led to a decline in cases NB: 3 most common = NHS Neisseria, Haemophilus, Streptococcus
  • 22. Gram Null • Chlamydia trachomatis • Chlamydophila pneumoniae (Chlamydia) Elementary body Reticulate body
  • 23. Summary – Bacteria Types Gram +ve • Coccus – Staph and Strep • Bacillus – Clostridium – Listeria – (anthracis) Gram -ve • Coccus – Neisseria • Cocco-bacillus – Haemophilus Everything else we need to know is Gram –ve bacillus, except Mycobacterium tuberculosis & Gardnerella vaginalis (plus the couple of Gram null ones).
  • 24. Antibiotics - types • Penicillins – Inc. co-amoxiclav • Cephalosporins – Cefotaxime – Ceftriaxone – Cefalexin • Macrolides – Clarithromycin – Erythromycin • Aminoglycosides – Gentamicin • Quinolones – Ciprofloxacin • Sulphonamides – Septrin (co-trimoxazole) – Trimethoprim • Tetracyclines – Doxycycline – Tetracycline • Others – Chloramphenicol – Metronidazole – Vancomycin
  • 25. Penicillins • Bacteriocidal • β-lactam (ring) activity – Inhibits peptidoglycan cross-linking • Usually active against Gram +ve orgs (e.g. penicillin, flucloxacillin, amoxicillin; co-amoxiclav broader spectrum) • Penicillin G – IV (benzylpenicillin sodium) • Penicillin V – oral (phenoxymethylpenicillin) • Benzathine benzylpenicillin – IM (special order: syphilis)
  • 26. Cephalosporins • Bacteriocidal • β-lactam activity • Less susceptible to penicillinases • Broad spectrum • E.g. ceftriaxone, cefotaxime (3rd generation)
  • 27. Carbapenems • Broad spectrum • β-lactam ring largely resistant to β-lactamases • E.g. meropenem, ertapenem
  • 28. Macrolides • Bacteriostatic • Macrolide ring activity – Binds irreversibly to 50S subunit of bacterial ribosome; inhibits protein synthesis • Used against Streptococci/MSSA in penicillin allergy • E.g. erythromycin
  • 29. Aminoglycosides • Bactericidal • Bind irreversibly to 30S subunit of bacterial ribosome – Prevents elongation of polypeptide chain (tRNA) • Good for Gram –ve aerobes • E.g. gentamicin
  • 30. Quinolones • Bactericidal • Bind to DNA gyrase-DNA complex – Inhibits DNA replication • E.g. ciprofloxacin
  • 31. Sulphonomides • Bacteriostatic • Compete with substrate of enzyme responsible for folic acid synthesis • E.g. trimethoprim
  • 32. Tetracyclines • Bacteriostatic • Prevent tRNA binding to 30S subunit – Inhibits protein synthesis • E.g. doxycycline
  • 33. Others • Metronidazole (imidazole) – Breakdown products disrupt DNA helix; inhibits nucleic acid synthesis – Good for anaerobes • Chloramphenicol – Interferes with protein synthesis • Vancomycin (glycopeptide) – inhibits cell wall synthesis – Gram +ve orgs • Anti-tuberculous drugs – Initial phase (1st 2 months) • Rifampicin • Isoniazid • Pyrazinamide • Ethambutol – Continuation phase (next 4months) • Rifampicin • Isoniazid
  • 34. Antibiotics used… • Infection by organ system • Reference: BNF • Highlighted in red = those we probably need to have a grasp of
  • 35. GI • Campylobacter enteritis – Ciprofloxacin or erythromycin • Salmonella – Ciprofloxacin or cefotaxime • Shigellosis – Ciprofloxacin. Amoxicillin or trimethoprim can be used if organism sensitive. • Typhoid fever – Ciprofloxacin or cefotaxime • Clostridium difficile infection – Oral metronidazole or oral vancomycin • Biliary-tract infection – Ciprofloxacin or gentamicin or a cephalosporin • Peritonitis – A cephalosporin + metronidazole or gentamicin + metronidazole or gentamicin + clindamycin or piperacillin with tazobactam
  • 36. CVS • Endocarditis initial ‘blind’ therapy – Flucloxacillin (or benzylpenicillin if symptoms less severe) + gentamicin • Endocarditis caused by staphylococci – Flucloxacillin • Endocarditis caused by streptococci (e.g. viridans streptococci) – Benzylpenicillin + gentamicin • Endocarditis caused by enterococci (e.g. Enterococcus faecalis) – Amoxicillin (or vancomycin if penicillin-allergic or penicillin- resistant) + gentamicin • Endocarditis caused by haemophilus, actinobacillus, cardiobacterium, eikenella, and kingella species (‘HACEK’ organisms) – Amoxicillin (or ceftriaxone if amoxicillin-resistant) + low-dose gentamicin
  • 37. RS • Haemophilus influenzae epiglottitis – Cefotaxime or chloramphenicol IV • Acute exacerbations of chronic bronchitis – Amoxicillin (or tetracycline or clarithromycin; approx. 20% H. influenzae strains amoxicillin-resistant) • Low or moderate-severity community-acquired pneumonia – Amoxicillin (or doxycycline or clarithromycin) • High-severity community-acquired pneumonia of unknown aetiology – Co-amoxiclav + clarithromycin • Pneumonia possibly caused by atypical pathogens – Clarithromycin. • Hospital-acquired pneumonia – Early-onset infection (less than 5 days after admission to hospital), co- amoxiclav or cefuroxime – Late-onset infection (more than 5 days after admission to hospital), an antipseudomonal penicillin (e.g. piperacillin with tazobactam) or a broad-spectrum cephalosporin (e.g. ceftazidime) or another antipseudomonal beta-lactam or a quinolone (e.g. ciprofloxacin)
  • 38. CNS • Meningitis initial empirical therapy – Benzylpenicillin or cefotaxime • Meningitis caused by meningococci – Benzylpenicillin or cefotaxime • Meningitis caused by pneumococci – Cefotaxime • Meningitis caused by Haemophilus influenzae – Cefotaxime • Meningitis caused by Listeria
  • 39. Urinary • Acute pyelonephritis – A broad-spectrum cephalosporin or a quinolone • Acute prostatitis – Ciprofloxacin or ofloxacin or trimethoprim • ‘Lower’ urinary-tract infection – Trimethoprim or nitrofurantoin or amoxicillin or oral cephalosporin (e.g. cefalexin)
  • 40. Genital • Syphilis – Benzathine benzylpenicillin (unlicensed) or doxycycline or erythromycin • Uncomplicated gonorrhoea – Ciprofloxacin. Pharyngeal infection requires ceftriaxone. • Uncomplicated genital chlamydial infection, non- gonococcal urethritis and non-specific genital infection – Azithromycin or doxycycline • Pelvic inflammatory disease – Doxycycline + metronidazole + i/m ceftriaxone or ofloxacin + metronidazole • Bacterial vaginosis – Oral or topical metronidazole or topical clindamycin
  • 41. ENT • Pericoronitis (infected wisdom tooth) – Metronidazole or amoxicillin • Acute necrotising ulcerative gingivitis – Metronidazole or amoxicillin • Periapical or periodontal abscess – Amoxicillin or metronidazole • Periodontitis – Metronidazole or doxycycline • Throat infections – Phenoxymethylpenicillin (or clarithromycin if penicillin-allergic) • Sinusitis – Amoxicillin or doxycycline or clarithromycin • Otitis externa – Flucloxacillin or clarithromycin • Otitis media – Amoxicillin (or clarithromycin if penicillin-allergic)
  • 42. Eye • Purulent conjunctivitis – Chloramphenicol or gentamicin eye drops
  • 43. Skin • Impetigo (superficial infection, Staph. aureus/Strep. pyogenes) – Topical fusidic acid (or mupirocin if methicillin- resistant Staph. aureus) • Erysipelas (Strep. pyogenes commonly  inflamed dermis) – Phenoxymethylpenicillin (or clarithromycin if penicillin-allergic) • Cellulitis – Benzylpenicillin + flucloxacillin (or clarithromycin alone if penicillin allergic) • Animal and human bites – Co-amoxiclav
  • 44. M/S • Osteomyelitis – Flucloxacillin or clindamycin if penicillin-allergic (or vancomycin if resistant Staph. epidermidis or metihcillin-resistant Staph. aureus) • Septic arthritis – Flucloxacillin or clindamycin if penicillin-allergic (or vancomycin if resistant Staph. epidermidis or methicillin-resistant Staph. aureus); cefotaxime if gonococcal arthritis or Gram-negative infection
  • 45. Antibiotic Resistance How? • Natural selection/environmental stresses (point mutations) • Horizontal gene transfer – Plasmid transferred via conjugation pilus (~sex) Why? • Poor hand hygiene spreads resistant orgs • Poor compliance (sub- optimal concentrations) • Prescribed unnecessarily
  • 46. Antibiotic Resistance • Some examples: – Meticillin-resistant Staphylococcus aureus (MRSA) • Wounds; ulcers; IV lines; abscesses…bacteraemia/septicaemia • Vancomycin/gentamicin • Trimethoprim/nitrofurantoin if UTI – Clostridium difficile • Diarrhoea…colitis…perforation/peritonitis • Vancomycin – Penicillin-resistant Streptococcus pneumoniae – Vancomycin-resistant enterococci – Multi-resistant salmonellae – Multi-resistant Mycobacterium tuberculosis • Streptomycin • Rx guided by sensitivity of infecting strain (BNF, 2009) (WHO)
  • 47. Eukaryotes • Candida albicans • Cryptosporidium parvum • Entamoeba histolytica • Giardia intestinalis • Pneumocystis jiroveci • Trichomonas vaginalis
  • 48. Candida albicans • Yeast  Candidiasis: – Cutaneous, GU, GI, resp. tract, systemic… • Opportunistic • Disease relates primarily to host immune state • Rx: – Topical e.g. clotrimazole – Oral e.g. fluconazole
  • 49. Cryptosporidium parvum • Protozoan  Cryptosporidiosis – Parasitic disease of mammalian GIT • Faeco-oral route of transmission • Diarrhoea, abdo pain, etc. • No therapeutic agent clearly identified as effective – Supportive Rx – fluids – Paromomycin may relieve diarrhoeal symptoms – ? new treatments • Rx: self-limiting if immunocompetent
  • 50. Entamoeba histolytica • Anaerobic protozoan • Amoebic dysentery – Bloody diarrhoea – Painful passage of stool – Colicy abdo pain • Amoebic abcesses of liver – Invades through GIT wall and spreads to other organs… • Rx: metronidazole/tinidazole
  • 51. Pneumocystis jiroveci • Yeast-like fungus • Common cause of pneumonia in AIDS • Opportunistic • Rx: co-trimoxazole + prophylaxis
  • 52. Giardia intestinalis • Flagellated protozoan  Giardiasis • Common waterborne disease; soil, food. • Faeco-oral route of transmission • Diarrhoea/abdo pain, etc. • Rx: metronidazole/tinidazole
  • 53. Trichomonas vaginalis • Protozoan  Trichomoniasis • STI – Vagina/urethra women • Frothy yellow-green discharge with strong odour • Dyspareunia/dysuria • Inflammation; increased risk HIV infection – Urethra/sometimes prostate men • Discharge • Irritation inside penis/dysuria • Rx: metronidazole/tinidazole
  • 54. Viruses • EBV • HAV • HBV • HCV • HEV • HIV • HPV • HSV • VZV • RSV • Influenza • Norovirus • Rhinovirus • Rotavirus
  • 55. EBV • Epstein Barr Virus = Human Herpes Virus 4 (HHV4) • Cold symptoms  infectious mononucleosis • Fatigue, fever, sore throat, lymphadenopathy • Risk if rupturing spleen so no sports for 1/12! • Acetaminophen/NSAIDs to help fever/pain • Normally remains in WBCs for life • Ca risk if prolonged infection • ? vaccines
  • 58. Human Papilloma Virus - HPV • Low risk – genital warts (STI)/skin warts • High risk: Ca cervix, vagina, vulva, anus, penis • Respiratory papillomatosis • Untreatable; usually clears spontaneously – Can treat the warts • Vaccines: Cervarix, Gardasil
  • 59. Herpes Simplex Virus - HSV • = Human Herpes Virus (1 &2) • Types: – Orofacial herpes (most common), i.e. herpes labialis (cold sores) – Genital herpes – Herpes whitlow (hands) – Ocular herpes (eyes) – Herpes encephalitis (brain)…+ others! • Watery blisters in skin/mucus membranes • Lies latent in nerve cell bodies; outbreaks • No cure per se – ? vaccines under development – Antivirals e.g. aciclovir cream – Analgesia – Anaesthesia (e.g. topical lignocaine)
  • 60. Varicella Zoster Virus - VZV • = Human Herpes Virus 3 • Fluid-filled blisters surrounded by reddened skin • General malaise, sore throat, headache, etc. • Rx: – Topical antivirals e.g. aciclovir – Ig for at risk individuals (neonates, pregnant, etc) – Vaccine in seronegative/at risk individuals • Varilrix/Varivax – Pain management post shingles
  • 61. Respiratory Syncitial Virus - RSV • Common cause of bronchiolitis/viral pneumonia in kids (< 6/12 mostly); • Older children/adults get a cold (limited to URT) • Rx: – Paracetamol/ibuprofen – Ribavirin • Inhibits range of DNA/RNA viruses – Palivizumab • Monoclonal Ab • Prevents serious LRTI in kids at risk
  • 62. Influenza • Oseltamivir and zanamivir as post- exposure prophylaxis – Inhibit neuraminidase • Vaccines – Seasonal • High risk individuals – Pandemic • Pandemrix/Celvapan for swine ‘flu • See lecture notes
  • 63. Norovirus • Winter vomiting bug; RNA virus • Most common cause of gastroenteritis in UK – D&V, fever, etc. • Faeco-oral route/contaminated food & water • Rx: – Stay at home – Paracetamol for fever symptoms – Rehydrate!
  • 64. Rotavirus • As for norovirus…
  • 65. Rhinovirus • Causes common cold; triggers acute asthma exacerbations • RNA virus • Aerosol-droplet; contaminated surfaces • No vaccine; supportive treatment only.
  • 66. Notifiable diseases! Anthrax Ophthalmia neonatorum Cholera Paratyphoid fever Diphtheria Plague Dysentery (amoebic or bacillary) Poliomyelitis, acute Encephalitis, acute Rabies Food poisoning Relapsing fever Haemorrhagic fever (viral) Rubella Hepatitis, viral Scarlet fever Leprosy Smallpox Leptospirosis Tetanus Malaria Tuberculosis Measles Typhoid fever Meningitis Typhus Meningococcal septicaemia (without meningitis) Whooping cough Mumps Yellow fever + Consultant in Communicable Disease Control should be informed BNF 59