Gram Positive Pathogens 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. http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter32/animation_quiz_4.html

Treatment of Infections Caused by Staphylococcus aureus Antistaphylococcal penicillins: Nafcillin, oxacillin First Generation cephalosporins: Cefazolin Second Generation Cephalosporins: Cefuroxime 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 LINK

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 (inflammation of small blood vessels in the kidney)

Streptococcus pyogenes

Streptococcus pyogenes Impetigo

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 Necrotizing fasciitis is a rare condition, also known as flesh-eating bacterial disease, that is usually caused by streptococci, but can also be caused by staphylococci. The disintegration of the skin tissue is due to the production of toxins, which may result in an overly-zealous response of the immune system.

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. In order of importance these microorganisms cause the following types of infections Urinary Tract Infections (UTIs) Intra - abdominal and intra - pelvic abscesses or postsurgery wound infections Blood stream infections (BSIs)

Enterococcus Resistance Mechanisms

Treatment of Infections Caused by Enterococcus 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 is a food-borne pathogen and is now recognized as a serious hazard by the food industry Listeria can cause septicemia and meningitis Listeria seems to particularly affect pregnant women, individuals with weakened immune systems, and newborns.

Listeria monocytogenes http://www.nature.com/nrmicro/animation/imp_animation/index.html

Treatment of Infections Caused by Listeria monocytogenes Ampicillin + Gentamicin If penicillin allergic: Trimethoprim-sulfamethoxazole +

Bacillus anthracis

Bacillus anthracis LINK

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: 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%. LINK

Enterobacteriaceae Shigella Escherichia coli Yersinia pestis Klebsiella pneumoniae Escherichia coli Salmonella

Escherichia coli

Klebsiella

Proteus

Escherichia coli. E. coli is a normal resident of the human intestinal tract and most strains are harmless. However, some strains acquire the ability to produce toxins and to invade the blood stream.

Certain strains of E. coli Certain strains of E. coli., like serotype O157:H7, however, can cause serious illness. E. coli is also a leading cause of urinary tract infections in women and also of meningitis in neonates. Link LINK http://www.drkoop.com/animation/93/43.html

Treatment of Infections Caused by: E. coli., K. pneumoniae, Proteus Aminopenicillins: Ampicillin First Generation Cephalosporins: Cefazolin Sulfa drugs: Trimethoprim-sulfamethoxazole Quinolones: Ciprofloxacin, levofloxacin, moxifloxacin

Treatment of Resistant Infections Caused by: E. coli. , K 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 Treatment of Resistant Infections Caused by: E. coli., K. pneumoniae, Proteus Extended Spectrum penicillins + b-lactamase inhibitor: Piperacillin-tazobactam, ticarcillin-clavulanate

Treatment of Resistant Infections Caused by: E. coli. , K 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: Trimethoprim-sulfamethoxazole 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. LINK Historical Link

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 b-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 Chloramphenicol

Treatment of Infections Caused by Neisseria Gonorrhoeae Third Generation Cephalosporins: Ceftriaxone, cefixime

Curved Gram Negative Bacilli Campylobacter jejuni, Helicobacter pylori, Vibrio cholerae

Campylobacter jejuni Camphylobacter jejuni is a common cause of gastroenteritis.

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 LINK

Vibrio cholerae Cholera is a bacterial infection of the small intestine. Cholera is spread by eating or drinking contaminated water or food.

Vibrio cholerae The main symptoms of cholera are watery diarrhea and vomiting, which can lead to rapid dehydration and death.

Treatment of Infection Caused by Vibrio cholerae Tetracyclines: tetracycline, doxycycline Sulfa drugs: Trimethoprim-sulfamethoxazole 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 + b-lactamase inhibitor: Amoxicillin/clavulanate Ampicillin/sulbactam Second-generation cephalosporin Cefuroxime Third-generation cephalosporin Ceftriaxone Cefotaxime

Bordetalla pertussis

Bordetalla pertussis causes a violent cough called ‘whooping cough’

Bordetella pertussis LINK

Treatment of Infection Caused by Bordetella pertussis Macrolides: Azithromycin, Clarithromycin, Erythromycin

Moraxella catarrhalis Causes otitis media, pneumonia, and sinusitis Usually produces b-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 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 LINK

Treatment of Infections Caused by Clostridium spp. Penicillin G Metronidazole (may be associated with better outcomes)

Clostridium difficile

Clostridium difficile LINK

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’ meaning ‘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 b-lactamase Prevotella Porphyromonas

Treatment of Anaerobic Gram-negative Infections b-lactam/b-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 LINK

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: 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 Link USMLE Study Song

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 http://www.nature.com/nrmicro/animation/imp_animation/index.html

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 Tularemia is contracted by contact with infected animals (squirrels) or through an arthropod vector (fleas, ticks, etc.)

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 LINK

Treponema pallidum

Treponema pallidum

LINK

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 http://www.chemblink.com/products/54-35-3.htm

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