Haemophilus Spp (Blood-loving bacteria) H. Influenzae Does not cause influenza, Why named so? mistakenly considered the cause of influenza 1890 Pandemic. Gram negative coccobacilli Obligate parasites of man Cause hidden disease because: Does not cause a specific disease Responding first with antibiotics may mask Hibs Difficult to isolate Fastidious, require X (hemine) and V (NAD or NADP) factors in chocolate agar A "Rapid Assessment Tool" has been developed by WHO and CDC to make sensible estimates of Hib H. Ducreyi : STD (soft chancroid) not common Opportunistic Haemophilus pathogens are rare
H. Influenza have no specific syndrome but can cause: meningitis, conjunctivitis, sinusitis, cellulitis, otitis, epiglottitis, pneumonia,Health Canada and www.cdc.gov/vaccines/pubs
One of the most transformable genomes H. Influenza was the first free living organism to have the complete genome sequenced in 1995 The genome consists of 1.8 MB of DNA in a single circular chromosome of which 1.7 code for proteins. How does it become highly-specific to humans?. Mutations,Transformable by many ways, Phase variation by DNA repeats
Diagnosis Microscopy to detect in CSF, synovial fluids, Culturing, difficult, may be not sensitive latex particle agglutination test (LAT) PCR H.Influenza Gram stain H.Influenza Choclate agar
Treatment and prophylaxis cefotaxime , ceftriaxone, ampicillin and sulbactam, cephalosporins of the second and third generation, or fluoroquinolones are preferred. Hib conjugate vaccine Hib is preventable, but there are two problems: A shortage of information : difficult to diagnose, it causes death without being recognized Expensive: Hib vaccine is expensive
Vibrio V. cholerae, and V. parahaemolyticus are human pathogensV. cholerae: cause cholera. Comma shaped rods , with Two circular chromosomes What is Cholera? Cholera toxin activates adenyl cyclase causing increased cAMP level and hypersecretion of fluids and electrolytes Extensive watery diarrhea (15-20 liters/day) called Rice-Water Stool: Colorless Odorless No protein Speckled with mucus Source contaminated waters and food Caused 8 cholera pandemics, example of Pandemic strain is El Tor Treatment and prevention Rehydration & supportive therapy Water purification, sanitation & sewage treatment Vaccines
Sack, David, et al. 2004. Seminar: Cholera. The Lancet. 363: 223-233.
Diagnosis Rapid tests Dark-field microscopy Rapid immunoassays Molecular methods – PCR & DNA probes Selective/differential culture medium - Thiosulfate Citrate Bile salts Sucrose (TCBS) agar V. cholerae grow as yellow colonies Biochemical and serological tests
Helicobacter H. pylori = gastritis, peptic ulcer disease(PUD) Helical (spiral or curved) corkscrew shape and lophotrichous (tuft at one pole)flagella helps in penetration and colonization of mucosal lining of stomach & duodenum Acid-inhibitory protein Hydrolyzes urea and inhibits acids in gastrics • Most gastric cancers are preceded by an infection with H. pylori Microaerophilic: Change chape to coccoid when exposed to oxygen or upon prolonged culture
Diagnostic aspects Detected in endoscopic antral gastric biopsy material Culture media containing whole or lysed blood Microaerophilic does not ferment or oxidize carbohydrates Triple Chemotherapy (synergism): Proton pump inhibitor (e.g., omeprazole = Prilosec(R)) One or more antibiotics (e.g., clarithromycin; amoxicillin; metronidazole) Bismuth compound
Mycobacterium tuberclosis: Tuberclosis 1/3RD of World has it, a global Emergency. TB what it is, and how it spreads?Outside body Inside body:Spreads through the air when a person with TB: bacilli go to lungs and infect alveoli Coughs Macrophages attack bacteria, but some survive Speaks Infected macrophages form tubercles Dead cells form granulomas Laughs Sneezes Sings http://www.cpmc.columbia.edu/resources/tbcpp/abouttb.html.
Symptoms for Pulmonary TB:There are many types of Tuberclosis, pulmonary is most important Perpetual Cough Fever Weight loss Night sweats Types of TB bacteria include: Mycobacterium tuberculosis Loss of appetite Mycobacterium leprae Fatigue Mycobacterium avium Swollen glands Chills Pain while breathing
Some diagnostics Acid fast staining, and Lowenstein-Jensen Agar Skin test- Mantoux test Purified Protein Derivative PPD injected in forearm and examined 2-3 days later Red welt around injection indicates infection Examine medical history, x-rays, and sputum
Treatment and prevention Take antibiotics for 6-12 months Preventative drug to destroy dormant bacteria For active TB, 4 medications: isoniazid, rifampin, ethambutol, and pyrazinamide Vaccines (relatively ineffective today) Check with X-ray
Spirochetes: Treponema, Borrelia, & Leptospira Spirochete means “coiled hair” Greek. They are tightly coiled like telephone cord, only a fraction of a micron in diameter but hundred of microns long Twisting Motility by periplasmic flagella (axial fibrils or endoflagella) is a major difference between this and other bacteria
Spirochaetes: Genus Treponema Genus: Treponema: Treponema pallidum, causes syphilis (sexually, or congenitally transmitted), delicate obligate parasite Stages of Syphilis: 1. Primary Chancre lesion is the main sign 2. Secondary rash 3. Latent , no sign but bacteria present 4.Tertiary, very complicated systemic Treponema pertenue, causes yaws skin lesion
Spirochetes Genus: Borrelia Borrelia burgdorferi, Causes a zoonotic vector borne disease called Lyme disease Transmitted by ticks Linear chromosome Borrelia recurrentis, causes relapsing fever Genus: Leptospira Leptospira species, causes leptospirosis Main Diagnostic tests for Spirochetes: Darkfield microscopy Fluorescent antibody staining VDRL Wasserman Test Hemagglutination tests
Treatment and control Penicillin remains drug of choice • WHO monitors treatment recommendations • 7-10 days continuously for early stage • At least 21 days continuously beyond the early stage Prevention of Mother-child transfer by barrier methods (e.g., condoms) Prophylactic treatment of contacts identified through epidemiological tracing Cautiousness, and morals play significant roles
Rickettsial Diseases Transmitted by Arthropod Vectors Fastidious, obligate intracellular bacteria that grow only on cells, eggs, and tissue cultures Transmitted by Arthropod Vectors They are pleomorphic & coccobacillary Do not show on Gram stain, but can be seen with either Gimenez or Giemsa stains Gimenez stain of tissue culture cells infected with Rickettsia rickettsii
Pathogenesis and Clinical Symptoms Pathogenesis for all these infections is very similar regardless of species. A vasculitis (inflammation of blood vessel wall) is caused by the invasion and multiplication of the organism in the endothelial and smooth muscle cells of the blood vessels.Clinical symtoms Thrombosis, occlusion, and necrosis of blood vessel walls Thrombocytopenia with hemorrhage – occurs primarily as a result of platelet consumption as opposed to true (DIC)disseminated intravascular coagulation Massive capillary leakage, edema, hypotension, and respiratory distress, encephalitis, myocarditis, & nephritis
Four Prototype Diseases 1. Rocky Mountain spotted fever… by Rickettsia rickettsii Fever, heache, rash… 2. Murine typhus…by Rickettsia typhi 3. Epidemic typhus …by Rickettsia prowazekii 4. Q fever…by Coxiella burnetii Occurs in veterinarians, ranchers, and animal researchers from infected placenta of sheep, cattle, or goats (no arthropod vector for C. burnetii). Pneumonia is common
Weil-Felix Reaction and the bit of a history Historical known that Proteus antibodis cross-reactive with several of the rickettsiae. Today, Weil-Felix test is not confirmed for rickettsial infection. In Poland during World War II, two physicians cleverly used killed Proteus bacteria to vaccinate the men of a small town, to induce a positive Weil-Felix reaction. The occupying Germans feared typhus epidemic and Due the vaccination reaction, the village was saved of a certain destruction. The men were not forced into the army, and the women and children were not forced into the camps.
Diagnosis and treatmentSpecific & sensitive tests: Indirect immunofluorescent antibody (IFA) Indirect hemagglutination antibody (IHA) Complement fixation (CF)Treatment In life-threatening rickettsial infections, early antibiotic intervention is recommended to prevent endothelial damage Doxycycline, tetracycline, and chloramphenicol are the drugs of choicePrevention (transmitted by vectors so avoid them) Use of repellents & protective clothing in endemic areas Inspection & removal of ticks Vaccine for RMSF is available for risk groups Weekly doxycycline