Transcript Gram Positive Pathogens • Staphylococcus • Streptococcus • Enterococcus

Gram Positive Pathogens
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Staphylococcus
Streptococcus
Enterococcus
Listeria monocytogenes
Bacillus anthracis
A ‘coccus’ is a
spherical bacteria
Staphylococcus tend
to cluster in groups
While Streptococcus
tend to line up in
strings
Gram-positive bacteria:
Staphylococci
Staphylococcus aureus
Staphylococcus aureus causes a variety of
suppurative (pus-forming) infections and toxinoses
in humans.
Important to distinguish
Staphylococcus from Streptococcus
• Most Staphylococcus are resistant to
Penicillin G
– Most produce a -lactamase
– Or, may be resistant due to mutation of PBP
(as in MRSA)
• Most Streptococcus are susceptible to
Penicillin G
Lipoteichoic Acid also present
As is Polysaccharide Capsule
•Proteins that Disable Our Immune Defenses Include:
•Protein A: Binds to IgG
•Coagulase: leads to fibrin formation around bacteria, preventing
phagocytosis
•Hemolysins
•Leukocidins
•Penicillinase
•Proteins that Tunnel Through Tissue Include:
•Hyaluronidase: breaks down proteoglycans in connective tissue
•Staphylokinase: Lyses formed fibrin clots
•Lipase: Degrades the fat protective layer on surface of skin
•Proease: Destroys tissue proteins
•Exotoxins Produced Include:
•Exfoliatin: causes skin to slough off (scalded skin syndrome)
•Enterotoxins: cause food poisoning (vomiting and diarrhea)
•Toxic Shock Syndrome Toxin (TSST-1): Causes massive T cell response
and outpouring of cytokines, resulting in toxic shock syndrome.
3 Major Pathogenic Types of
Staphylococcus:
• Staphylococcus aureus
– Many types of infections
• Staphylococcus epidermidis
– Most common cause of infection in indwelling
prosthetic devices (prosthetic joints, heart valves,
etc.)
• Staphylococcus saprophyticus
– Leading cause of urinary tract infections in sexually
active young women
Staphylococcal Scalded Skin
Syndrome (SSSS)
Staphylococcus causes superficial skin lesions
such as boils, styes and furunculosis;
Staphylococcus also causes more serious infections such
as pneumonia, mastitis (inflammation of mammary
gland), phlebitis (inflammation of vein, usually in leg),
meningitis (inflammation of meninges), and urinary tract
infections;
Staphylococcus also causes deep-seated
infections, such as osteomyelitis (inflammation
of the bone) and endocarditis (inflammation of
heart).
S. aureus is a major cause of hospital acquired (nosocomial) infection of
surgical wounds and infections associated with indwelling medical devices.
S. aureus causes food poisoning by releasing
enterotoxins into food, and toxic shock
syndrome by release of superantigens into the
blood stream.
Superantigens and TSS
Toxic Shock Syndrome can occur via skin, vagina, or
pharynx
There has been some indication that it was associated
with selected materials used in some ultra-abosorbant
tampons. These materials are no longer used in the
US.
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Treatment of Infections Caused by
Staphylococcus aureus
• Antistaphylococcal penicillins: Nafcillin, oxacillin
• First Generation cephalosporins: Cefazolin
• Second Generation Cephalosporins: Cefurxime
• Third-generation cephalosporins: Ceftriaxone,
cefotaxime, ceftizoxime
-Lactam/ -lactamase inhibitor combinations:
Ampicillin-sulbactam, piperacillin-tazobactam,
ticarcillin-clavulanate
• Carbapenems: Imipenem, meropenem
Treatment of Infections Caused by Staphylococcus
aureus (NOT methicillin resistant)
Treatment of Methicillin-resistant
Staphylococcus aureus
• Vancomycin
Treatment of Methicillin-resistant
Staphylococcus aureus
• Linezolid
Treatment of Methicillin-resistant
Staphylococcus aureus
• Streptogramins (Quinupristin-dalfopristin)
Treatment of Methicillin-resistant
Staphylococcus aureus
• Daptomycin
(cubicin)
Treatment of Methicillin-resistant
Staphylococcus aureus
• Tigecycline
(Tygacil)
Doxycycline
Gram-positive pathogens:
Streptococcus pneumoniae
Types of Streptococci
• Group A beta-Hemolytic Streptococci
– Streptococcal pharyngitis (Strep throat)
– Streptococcal skin infections
– Scarlet Fever
– Streptococcal toxic shock syndrome
– Rheumatic fever
– glomerulonephritis
Streptococcus pyogenes
Streptococcus pyogenes
Treatment of Streptococcus
pyogenes
• Penicillin G
• Aminopenicillins: Ampicillin
• Aminoglycosides are sometimes added for
synergy: Gentamicin
Treatment of Streptococcus
pyogenes
• Clindamycin is added for severe invasive
Streptococcus pyogenes infections
Treatment for Penicillin-resistant
Streptococcus pyogenes (and other
penicillin resistant Streptococcus)
• Vancomycin
• Second-generation cephalosporins:
Cefuroxime
• Third-generation cephalosporins:
cefotaxime, ceftriaxone
Necrotizing Fasciitis
Types of Streptococci (Group B)
• Viridans Group Streptococci
– Dental Infections
– Endocardidis
Types of Streptococci (Group D)
• Streptococcus pneumoniae
S. pneumoniae is a common cause of otitis media (ear
infection) and is also a major cause of bacterial
pneumonia.
Otitis media
Streptococcus pneumoniae
Treatment of Streptococcus
pneumoniae
Ampicillin
• Penicillin G (high doses)
• Aminopenicillins: Ampicillin (high doses)
Treatment of Penicillin-resistant
Streptococcus pneumoniae
• Second Generation Cephalosoporins:
Cefuroxime
• Third Generation Cephalosporins:
Cefotaxime, Ceftriaxone
• Quinolones: Moxifloxacin, Levofloxacin
• Vancomycin
• Macrolides/ketolines: Telithromycin
Enterococci
Enterococcus
Enterococci are gram positive cocci, that are normal residents of the GI
tract
Two common species are Enterococcus faecalis and Enterococcus
faecium.
Enterococcus Resistance Mechanisms
Treatment of Infections Caused by
Enterococcus
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Penicillin G
Aminopenicillins: Ampicillin
Extended-spectrum Penicillins: Piperacillin
Carbapenems: Imipenem, meropenem
Treatment of Infections Caused by
Enterococcus
• For serious infections, add an
aminoglycoside for synergy: Gentamicin
Treatment for Infections Caused by
Penicillin-resistant Enterococci
• Vancomycin
Treatment for Vancomycin
Resistant Enterococci (VRE)
• Linezolid
• Tetracycline-like:
Tigecycline
Gram-positive Bacteria:
Listeria Monocytogenes
Listeria monocytogenes
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Treatment of Infections Caused by
Listeria monocytogenes
• Ampicillin + Gentamicin
• If penicillin allergic:
– Trimethoprim-sulfamethoxazole
Bacillus anthracis
Bacillus anthracis
Bacillus anthracis
Treatment of Infections Caused by
Bacillus anthracis
• Quinolones: Ciprofloxacin
Treatment of Infections Caused by
Bacillus anthracis
• Tetracycline: Doxycycline
Treatment of Infections Caused by
Bacillus anthracis
• For Inhalation Anthrax, a Second Agent Should
be Added from the Following List:
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Rifampin
Vancomycin
Penicillin G
Ampicillin
Chloramphenicol
Carbapenem: Imipenem
Clindamycin
Macrolide: Clarithromycin
Gram-negative Bacteria:
Enterobacteriaceae
Septic Shock
• Septic shock is a condition of hypotension
(severely reduced blood pressure) caused by
decreased tissue perfusion and oxygen delivery.
• Septic shock can lead to multiple organ
dysfunction syndrome and death, with the
mortality rate approx. 50%.
Enterobacteriaceae
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Escherichia coli
Salmonella
Shigella
Yersinia pestis
Escherichia coli
Klebsiella
Proteus
Escherichia coli.
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Treatment of Infections Caused by:
E. coli., K. pneumoniae, Proteus
• Aminopenicillins: Ampicillin
• First Generation Cephalosporins:
Cefazolin
• Sulfa drugs: Trimethoprimsulfamethoxazole
• Quinolones: Ciprofloxacin, levofloxacin,
moxifloxacin
Treatment of Resistant Infections Caused by:
E. coli., K. pneumoniae, Proteus
• Third Generation Cephalosporins:
Cefoxaxime, ceftriaxone, ceftizoxime
• Monobactam: Aztreonam
Treatment of Resistant Infections Caused
by: E. coli., K. pneumoniae, Proteus
• Extended Spectrum penicillins + -lactamase
inhibitor: Piperacillin-tazobactam, ticarcillinclavulanate
Treatment of Resistant Infections Caused
by: E. coli., K. pneumoniae, Proteus
Meropenem
• Carbapenems: Imipenem, meropenem,
ertapenem
• Carbapenem + aminoglycoside in serious
infections: Add Gentamicin, Tobramycin,
amikacin
Treatment of Infections Caused by:
Enterobacter, Serratia, Citrobacter,
Providencia, and Morganella Spp.
• Carbapenems: Imipenem, meropenem,
ertapenem
• Sulfa Drugs: Trimethoprimsulfamethoxazole
• Quinolones: Ciprofloxacin, levofloxacin
• Fourth Generation Cephalosporins:
Cefepime
• + aminoglycoside: Gentamicin,
tobramycin, amikacin
Treatment of Infections Caused by:
Salmonella enterica, Shigella spp.
• Quinolones: Ciprofloxacin
• Third-generation cephalosporins:
Cefotaxime, ceftriaxone, ceftizoxime
• Macrolides: Azithromycin
Treatment of Infections Caused by:
Yersinia spp.
Treatment of Infections Caused by:
Yersinia spp.
Gentamycin
• Aminoglycosides: Gentamicin, streptomycin
Treatment of Infections Caused by:
Yersinia spp.
• Tetracyclines: Doxycycline
Treatment of Infections Caused by:
Yersinia spp.
•Quinolones: Ciprofloxacin
•Sulfa drugs
Gram-negative Bacteria:
Pseudomonas
Pseudomonas
Pseudomonas aeruginosa
Resistance of Pseudomonas
Treatment of Infections caused by
Pseudomonas aeruginosa
• Extended spectrum penicillins: Piperacillin,
Ticarcillin
• Third Generation Cephalosporins: Ceftazidime
• Fourth-generation Cephalosporins: Cefepime
• Carbapenems: Imipenem, meropenem
• Monobactams: Aztreonam
• Quinolones: Ciprofloxacin, Levofloxacin
• Aminoglycosides: Gentamicin, tobramycin,
amikacin
Treatment of Serious Infections Caused
by Pseudomonas aeruginosa
• Antipseudomonal -lactam + aminoclycoside:
Ceftazidime + Tobramycin
Treatment of Serious Infections Caused
by Pseudomonas aeruginosa
• Extended-spectrum penicillin +
antipseudomonal quinolone: Piperacillin +
Ciprofloxacin
Neisseria
Neisseria meningitidis
• The meninges are a series of membranes
surrounding the central nervous system
• They consist of three layers: the dura
matter, the arachnoid matter, and the pia
matter
Neisseria meningitidis
Neisseria meningitidis
Neisseria gonorrhoeae
Neisseria gonorrhoeae
Treatment of Infections Caused by
Neisseria meningitidis
• Penicillin G
• Third generation cephalosporins:
Ceftriaxone, cefotaxime
Treatment of Infections Caused by
Neisseria Gonorrhoeae
• Third Generation Cephalosporins:
Ceftriaxone, cefixime
Curved Gram Negative Bacilli
– Campylobacter jejuni,
– Helicobacter pylori,
– Vibrio cholerae
Campylobacter jejuni
Campylobacter jejuni
Treatment of Infection Caused by
Campylobacter jejuni
Azithromycin
• Macrolides: Erythromycin, azithromycin,
clarithromycin
• Link
Treatment of Infection Caused by
Campylobacter jejuni
• Quinolones: Ciprofloxacin
Helicobacteri pylori
Helicobacter pylori
Helicobacter pylori
Duodenal Peptic Ulceration
Caused by Helicobacter pylori
Treatment of Infection Caused by
Helicobacter pylori
• Amoxicillin + clarithromycin + proton pump
inhibitor
• Metronidazole + clarithromycin + proton
pump inhibitor
• Bismuth subsalicylate + metronidazole +
tetracycline + proton pump inhibitor
Vibrio cholerae
Vibrio cholerae
Cholera Epidemic in Zimbabwe Continues to
Worsen
Vibrio cholerae
Treatment of Infection Caused by
Vibrio cholerae
• Tetracyclines: tetracycline, doxycycline
• Sulfa drugs: Trimethoprimsulfamethoxazole
• Quinolones: Ciprofloxacin
• Macrolides: Erythromycin, Azithromycin
Haemophilus influenzae
Haemophilus influenzae
•Haemophilic means ‘blood loving’. The organism
requires a blood-containing medium for growth
•Influenzae: The bacterium often attacks the lungs
of a patient with viral influenza.
• Since the organism was
frequently isolated from
the lungs of patients
during the 1890 and 1918
influenza pandemics,
scientists incorrectly
concluded that the
bacterium was the
causative agent.
Haemophilus influenzae
Haemophilus influenzae
Treatment of Infections Caused by
Haemophilus influenzae
• Aminopenicillins + -lactamase inhibitor:
– Amoxicillin/clavulanate
– Ampicillin/sulbactam
• Second-generation cephalosporin
– Cefuroxime
• Third-generation cephalosporin
– Ceftriaxone
– Cefotaxime
Bordetalla pertussis
Bordetalla pertussis
• Bordetalla pertussis causes a violent
cough called ‘whooping cough’
Bordetella pertussis
Treatment of Infection Caused by
Bordetella pertussis
• Macrolides: Azithromycin, Clarithromycin,
Erythromycin
Moraxella catarrhalis
• Causes otitis media, pneumonia, and
sinusitis
• Usually produces -lactamase
Treatment of Infections Caused by
Moraxella catarrhalis
• Extended spectrum penicillins: piperacillin,
ticarcillin
 -lactam/-lactamase inhibitor
combinations: piperacillin/tazobactam,
ticarcillin/clavulanate
• Second and third-generation
cephalosporins
Acinetobacter
• Recent outbreak among soldiers
in Iraq
• Second leading cause of
infection among troops during
the Vietnam conflict
Acinetobacter
Treatment of Infection Caused by
Acinetobacter
• Sulbactam
• Carbapenems
• Quinolones
Anaerobic Bacteria
Gram positive: Clostridia spp.
Clostridium tetani
• Clostridium tetani is the etiologic agent of tetanus
• Characterized by persistent tonic spasm, usually
involving the masseter muscles (lockjaw)
• Usually caused by deep wound becoming infected with
C. tetani spores.
Clostridium botulinum
• Clostridium botulinum is usually acquired by
ingestion of food contaminated with C.
botulinum spores
• Botulinum toxin leads to cranial neuroopathies
and weakness rather than muscular spasm.
• Link
Botulinum Toxin (Botox)
• Botulinum toxin is a neurotoxic protein
produced by Clostridium botulinum
• It was discovered in the 1950’s that
injecting small amounts decreased muscle
activity by blocking release of
acetylcholine at the neuromuscular
junction
Botulinum Toxin (Botox)
LINK
Treatment of Infections Caused by
Clostridium spp.
• Penicillin G
• Metronidazole (may be associated with
better outcomes
Clostridium difficile
Clostridium difficile
Treatment of Infections Caused by
Clostridium difficile
• Oral metronidazole
• Oral vancomycin
Clostridium perfringens is the
cause of gas gangrene
Gas Gangrene
• Gangrene comes from the Greek ‘gangraina’
meaing ‘putrefication of tissues’
• Dry gangrene often occurs in the toes and feet of
elderly patients
• Wet gangrene occurs in naturally moist tissues,
such as the mouth, bowel, lungs.
• Gas gangrene is due to infection by Clostridium
perfringens, which produces gas within the tissues.
• Such gas-producing infection spreads very rapidly,
and should be considered a medical emergency.
Treatment of Infections Caused by
Clostridium perfringens
• Penicillin + one of the following:
– Clindamycin
– Tetracycline
– Metronidazole
Hyperbaric Oxygen Therapy
One treatment for gas gangrene includes hyperbaric oxygen therapy
Anaerobic Gram-negative Bacteria
Common Anaerobic Gram-negative
Pathogens
• Bacteroides fragilis
– Usually produces -lactamase
• Prevotella
• Porphyromonas
Treatment of Anaerobic Gramnegative Infections
 -lactam/-lactamase inhibitor
combinations
– Ampicillin-sulbactam
– Piperacillin-tazobactam
– Ticarcillin-clavulanate
• Carbapenems: Imipenem, Meropenem,
Ertapenem
• Metronidazole
Atypical Bacteria: Chlamydia
Chlamydia trachomatis
• One of the most
common sexually
transmitted
diseases
• Also a leading
cause of blindness
in some parts of the
world
Chlamydia trachomatis
Chlamydia is a bacterial infection of the genital tract spread through sexual
contact. If untreated, it can result in various medical complications, including
damage to the reproductive organs.
The disease affects both women and men, although reported cases for women
greatly exceed those for men. Chlamydia affects people in all age groups, but it
is particularly prevalent among teenagers and young adults. According to the
U.S. Centers for Disease Control and Prevention (CDC), the infection is most
prevalent among women aged 20 to 25.
Chlamydia trachomatis
Some signs and symptoms that may be present in people infected with
chlamydia are:
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Abnormal discharge from the penis or vagina
Burning sensation during urination
Lower abdominal or back pain
Nausea
Fever
Pain during intercourse
Burning or itching around the head of the penis
Swollen or tender testicles
Bleeding between menstrual cycles
Proctitis (inflammation of the rectum)
Life Cycle of Chlamydia trachomatis
Treatment of Infections Caused by
Chlamydia trachomatis
• Tetracyclines
– Tetracycline
– Doxycycline
• Macrolides
– Azithromycin
– Erythromycin
– Telithromycin
• Quinolones
– Ofloxacin
– Moxifloxacin
– Gemifloxacin
Mycoplasma pneumoniae
Mycoplasma pneumoniae
Treatment of Infections Caused by
Mycoplasma pneumoniae
• Macrolides: Azithromycin, clarithromycin,
erythromycin telithromycin
• Tetracyclines: Tetracycline, doxycycline
• Quinolones: Levofloxacin, moxifloxacin,
gemifloxacin
Atypical Bacteria: Legionella
• Legionella pneumophila is
the most common
species, and is the
causative agent of
Legionaires’ disease
• Once in the lung,
Legionella organisms are
taken up by macrophages
and multiply within them.
Legionalla pneumophila
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Treatment of Infections Caused by
Legionella pneumophila
• Macrolides: Azithromycin
• Quinolones: Levofloxacin, moxifloxacin
Brucella
• Brucellosis is a disease of animals, that is
occasionally transmitted to humans
• Contact with animals and/or ingestion of
unpasteurized milk or cheese are risk
factors
Brucella
Brucella
Treatment of Infections Caused by
Brucella spp.
• Doxycycline + rifampin
• Doxycycline + gentamicin
• Doxycycline + streptomycin
Francisella tularensis
Francisella tularensis
Treatment of Infections Caused by
Francisella tularensis
• Aminoglycosides: Streptomycin,
Gentamicin
• Tetracyclines: Tetracycline, doxycycline
Rickettsia spp
Rickettsia rickettsii
Rocky Mountain spotted fever is the most severe and most frequently reported
rickettsial illness in the United States. The disease is caused by Rickettsia
rickettsii, a species of bacteria that is spread to humans by ixodid (hard) ticks.
Treatment of Infections Caused by
Rickettsia spp.
• Tetracyclines
– Doxycycline
– Tetracycline
Spirochetes: Treponema pallidum
Treponema pallidum
Treponema pallidum
Treponema pallidum
Treatment of Infections Caused by
Treponema pallidum
• Penicillin G (including benzathine
penicillin)
• Tetracyclines
• Third Generation Cephalosporins
Penicillin procaine
Penicillin benzathine
These particular salts of
penicillin are injected
intramuscularly and
absorbed slowly over a
period of time.
Penicillin G benzathine
Procaine penicillin G
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Borrelia borgdorferi
Borrelia burgdorferi
Borrelia burgdorferi is the causative
agent of Lyme Disease
Treatment of Infections Caused by
Borrelia burgdorferi
• Tetracyclines: Doxycycline
• Aminopenicillins: Amoxicillin
Leptospira interrogans
Leptospira interrogans
Treatment of Infection Caused by
Leptospira interrogans
• Tetracyclines: Doxycycline
• Aminopenicillins: Amoxicillin
• Severe Disease can be treated with
Penicillin G, Ampicillin, or Ceftriaxone
Mycobacteria
• Mycobacterium tuberculosis
• Mycobacterium avium complex
• Mycobacterium leprae
Mycobacterium tuberculosis
Link
Mycobacterium tuberculosis
Mycobacterium tuberculosis
Treatment of Infections Caused by
Mycobacterium tuberculosis
• Active Disease
– Isoniazid + Rifampin + Pyrazinamide +
Ethambutol for two months
– Followed by: Isoniazid + Rifampin for Four
months
• Latent Disease
– Isoniazid for 9 months
Mycobacterium avium complex
Mycobacterium avium complex
Treatment of Infections Caused by
Mycobacterium avium complex (MAC)
• Clarithromycin + ethambutol + rifabutin
Mycobacterium leprae
Mycobacterium leprae
Leprosy
Treatment of Infections Caused by
Mycobacterium leprae
• Dapsone + rifampin + clofazimine