Microbiology test 3

Actinomycetes

A group of filamentous, fungus like bacteria. Cause actinomycosis, a cervicofacial disease resulting from complications in tooth extraction or poor oral hygiene.

endospore

A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions. Location can be used in cell identification: central, terminal, or subterminal.

Mycobacterium leprae

Acid fast, bacillus causative agent of leprosy Cannot be cultured in lab Slowest growing of all species; incubation period is 2 - 5 years. Leprosy - progressive skin and nerve disease that leads to disfigurement. Small, spotty lesions on trunk and extremities Wasting of muscles, loss of control. Diagnosis: Feather test Numbness Loss of hot/cold sensitivity Thickened earlobes Treatment: Antibiotic drug cocktails prior to nerve damage Prevention: Vigilance in endemic areas Vaccine clinical trial

Mycobacterium tuberculosis

Acid fast, bacillus, does not Gram stain, Do not form capsules, flagella or spores Generation time is 2 hours to several days 1/3 of the world carries the bacillus Tubercle - long, thin bacillus in masses or strands called cords Causative agent of tuberculosis treatment: 6 to 24 months of antibiotics detection: x-rays, tuburculin testing (PPD), acid fast bacteria in sputum, isolation and identification

Bubonic Plague

Bacillus enters the lymph from the flea bite and causes necrosis and swelling of the node called a bubo, usually in the groin or axilla. After the 2 to 8 day incubation period, the patient expresses symptoms of fever, chills, headache, nausea, weakness and tenderness. Septicemic Plague - bacterial growth in the blood resulting in intravascular coagulation, subcutaneous hemorrhage that may become gangrene and become necrotic. Pneumonic Plague - infection remains in the lungs and can be transmitted with aerosols

Tuberculosis

Course of Infection: Initial Infection and Primary Tuberculosis Latent and Recurrent Disseminated/Extrapulmonary Tuberculosis Humans are easily infected, but resistant to the disease. Can be infected young and develop disease as an adult Treatment: 6 to 24 months of antibiotics

Actinomyces israelii

Filamentous bacteria, Branching, gram + rods with sulfur granules Swollen, tender nodules in neck, Thoracic from lung necrosis, Abdominal from burst appendixes, wounds or ulcers, Uterine due to IUD,

Bacillus cereus

Gram +, bacilli, aerobe, forms central spores Causes food-borne illness due to the release of enterotoxins. "Fried Rice Syndrome" Nausea, vomiting, diarrhea and abdominal cramps. No treatment, resolves in 24 hours

Clostridium perfringens

Gram +, bacilli, anaerobe, central or terminal spores Found in soil and sewage Virulence factors: alpha toxin, collagenase, hyaluronidase, DNase Diseases: Gas Gangrene (anaerobic cellulitis, true myonecrosis) Treatment: Cephalosporins or penicillin, Hyperbaric oxygen therapy, Debridement, Potential amputation Gastroenteritis

Clostridium tetani

Gram +, bacilli, anaerobe, forms terminal spores Portal of entry: cutaneous wounds, burns, umbilical cords or frostbite, "Rusty nail" Incubation period is 4 - 10 days Main virulence factor is tetanospasmin neurotoxin. Treatment: antitoxin therapy, penicillin or tetracycline, muscle relaxants, Prevention: DTaP vaccine

Clostridium botulinum

Gram +, bacilli, anaerobe, spore forming inhabits soil and vegetation. Associated with low-acid canned food (home canning) and some meats and dairy products. Honey is implicated in infant botulism Botulinum toxin is the most potent and dangerous toxin known. Diseases: Infant botulism, wound botulism, Treatment: antitoxin therapy, penicillin, wound care Toxin is heat labile and can be destroyed at 100 C for 10 minutes.

Clostridium difficile

Gram +, bacilli, anaerobic, spore forming Cause "antibiotic-associated colitis", a superinfection due to use of broad spectrum antibiotics. Enterotoxins cause necrosis of intestinal wall, diarrhea, cramps, fever and pseudomembranes in colon. Characteristic stool odor. Treatment: Vancomycin or metronidazole Stopping previous antibiotics Fluid replenishment Stool transplant

Bacillus anthracis

Gram +, bacilli, facultative anaerobe, central spores (outside the human body), Common in livestock and animal products, Virulence Factors: polypeptide capsule, exotoxins Diseases: cutaneous anthrax, pulmonary anthrax Treatment - use of penicillin, doxycycline or ciprofloxacin antibiotics. Must also treat the toxemia with antibodies treatment of area with chlorine dioxide gas has been used as an agent of bioterrorism. World War II bombs Anthrax-laced letters of 2001

Staphylococcus saprophyticus

Gram +, cocci clustered, non-spore forming, non-motile, facultative anaerobes, catalase +,coagulase negative, second most common organism of UTIs.

Streptococcus pneumoniae

Gram +, cocci, chains, no spore, not motile, facultative anaerobes, catalase -, "pneumococcus" 60 -70% of bacterial pneumonias Also causes otitis media or meningitis, most common cause of bacterial meningitis. Alpha hemolytic. Treated with Penicillin G or V, cephalosporins, sulfonamides, quinolones or erythromycin.

Streptococcus pyrogens

Gram +, cocci, chains, no spore, not motile, facultative anaerobes, catalase -, Group A, Virulence factors: C carbohydrates, lipotechoic acid, M protein, Beta hemolysin, pyrogenic toxin, superantigens skin diseases: impetigo or pyroderma, erysipelasedema. Pharyngeal disease: "strep throat." Systemic disease: scarlet fever. Long term effects: rheumatic fever, acute glomerulonephritis. Most strains are sensitive to penicillins, erethromycin, and cephalosporin.

Streptococcus agalactiae

Gram +, cocci, chains, no spore, not motile, facultative anaerobes, catalase -, Group B, Common in cattle and as a normal microbe in the vagina, pharynx and large intestine. Causes wound and skin infections, endocarditis and neonatal meningitis. Pregnant women should be screened Beta hemolytic Treated with Penicillin G, vancomycin or cephalosporin.

Streptococcus species

Gram +, cocci, chains, no spore, not motile, facultative anaerobes, catalase -, categorized into Lancefield groups

Staphylococcus aureus

Gram +, cocci, clustered, non-spore forming, non-motile, facultative anaerobes, catalase + Virulence factors: coagulase, hyaluronidase, hemolysins, enterotoxin, exfoliative toxin, toxic shock syndrome toxin. localized diseases: folliculitis, furuncle, carbuncle, impetigo. Systemic diseases: osteomylitis, pneumonia. Toxigenic diseases: food intoxication, scalded skin syndrome, toxic shock syndrome. Treatment: most are resistant to penicillins, less resistant forms are treated with sulfa drugs, tetracyclins and clindamycin. Prevention: good hygiene for hands, surgical sites, and medical devices

Staphylococcus capitis

Gram +, cocci, clustered, non-spore forming, non-motile, facultative anaerobes, catalase +, coagulase negative, Normal flora of the scalp, face and external ear. Typically enter the body through breaks in the skin or indwelling medical devices.

Staphylococcus epidermis

Gram +, cocci, clustered, non-spore forming, non-motile, facultative anaerobes, catalase +, coagulase negative, normal flora of the skin

Enterococci

Gram +, cocci, diplo, Group D, catalase -, no hemolysis, Enterococcus faecalis, E. faecium, and E. durans. Normal inhabitants of the large intestine. Infections with E. faecalis are common in elderly patients undergoing surgery and affect the urinary tract, wounds, blood, endocardium and appendix. Alpha, beta or non-hemolytic. Treatment requires combined ampicillin and aminoglycosides (gentamycin)., Group D Strep

Listeria monocytogenes

Gram +, coccobacillus, non spore forming, motile with one to four flagella, Inhabit soil, plants, water, mammals, birds, fish and invertebrates Virulence Factor: Remains within the macrophage and continues to replicate thereby avoiding other cells of the immune system. Disease: Listeriosis Associated with dairy, poultry and meats Immunocompromised people are at a high risk Symptoms include fever, diarrhea, sore throat and it is potentially harmful to the meninges. May result in miscarriage ZERO TOLENRANCE POLICY

Propionibacterium acnes

Gram +, pleomorphic cell, Aerotolerant or aerobic Does not produce any toxins Resides in the sebaceous glands of skin Associated with acne

Corynebacterium diphtheriae

Gram +, pleomorphic, non spore forming, Low incidence in the US Prevention with DTaP vaccine Virulence factor: diptherotoxin, has fragment B (binds to cells in heart and nervous system), and fragment A (inhibits protein synthesis) Local Infection - usually in upper respiratory tract or as a secondary cutaneous infection. Sore throat, nausea, vomiting, swollen lymph nodes, neck swelling and fever. Pseudomembrane often forms over the pharynx Toxemia occurs when toxin enters the blood and travels to the heart and nerves, causing myocarditis, muscle weakness and paralysis

Nesseria species

Gram -, bean shaped cocci, found in pairs with sides touching

Nesseria meningitidis

Gram -, bean shaped cocci, found in pairs with sides touching, "Meningococcus" Virulence Factors: polysaccharide capsules and fimbriae, protease against IgA, lipopolysaccharide endotoxin Diagnosis: spinal tap looking for Gram negative cocci Diseases: Second most common cause of meningitis (fever, sore throat, headache, stiff neck, convulsions and vomiting) commonly seen in: dormitories, day cares, military barracks, and others living in close quarters. Treatment with third generation cephalosporins. Prevention with vaccination.

Nesseria gonorrhoeae

Gram -, bean shaped cocci, found in pairs with sides touching, "Gonococcus" STI or transferred during childbirth. often combined with another STI. Virulence Factors: fimbriae, protease (cleaves antibody IgA) Diseases: Males: 10% asymptomatic, urethritis, painful urination and discharge, can lead to infertility Females: 50% asymptomatic, bloody, vaginal discharge, painful urination, ectopic pregnancy or infertility can occur, PID Diagnosis: usually gram stain of urethral, vaginal or cervical swab. This is a reportable disease. Treatment: use of broad spectrum antibiotics like tetracycline or azithromycin.

Shigella

Gram -, rod Causative agent of shigellosis/bacillary dysentery Shigella dysenteriae, S. sonnei, S. flexnari, S. boydii Acquired through fecal - oral contamination Lax sanitation Malnutrition Crowded conditions Common in day care centers, prisons, medical institutions, nursing homes and military camps.

Proteus

Gram -, rod Non-coliform saprobe found in soil, sewage, water and as a commensal on humans. Does not cause disease in immunocompetant people. Can cause UTI with kidney stones, wound infections, pneumonia, septicemia and infant diarrhea.

Salmonella enteritidis

Gram -, rod Salmonella Gastroenteritis is caused by Salmonella enteritidis and is the common form of Salmonella food poisoning. Chickens and other poultry Chicken eggs Milk and homemade ice cream Reptiles also harbor the organism Symptoms: Vomiting, diarrhea, mucosal lesions. Symptoms last for 2 - 5 days

Yersinia

Gram -, rod This genus contains three species all of which cause zoonotic infections called yersinoses. Y. enterolitica and Y. pseudotuberculosis are intestinal inhabitants of wild and domestic animals that cause enteric infections in humans, and Y. pestis is the nonenteric agent of the bubonic plague.

Legionella pneumophila

Gram -, rod causative agent of legionnaire's disease found in aquatic environments such as tap water, pools, water towers, vegetable sprayers and AC units. Symptoms include fever, cough, diarrhea, abdominal pain and potential pneumonia. Prevalent in males over 50, the elderly, patients with diabetes, malignancies or transplants, smokers and alcoholics. No transmission from person to person Treatment with erythromycin and rifampin.

Pasteurella multocida

Gram -, rod Normal microbiota of animals that can cause infections in animals or in veterinarians. Cholera illness in chickens Hemorrhagic septicemia in cattle Bites and scratches can lead to local abscesses that spread to joints, lymph nodes and bones. Immunocompromised people can experience septicemia and heart and nervous system complications.

Haemophilus influenzae

Gram -, rod a cause of bacterial meningitis. Symptoms of fever, stiff neck, vomiting and neurological decline. Treated with third generation cephalosporins

Haemophilus parainfluenzae

Gram -, rod a normal flora organism that can cause endocarditis in adults with congenital or rheumatic heart diseases.

Haemophilus ducreyi

Gram -, rod causes chanchroid, an STI in the tropics and subtropics that causes lesions in the genital area that develop into painful necrotic ulcers.

Haemophilus aegypticus

Gram -, rod causes conjunctivitis or pink eye. This disease is spread through contaminated fingers and shared personal items. Treatment with antibiotic eye drops.

Acinetobacter baumanii

Gram -, rod found in soil and water. It can survive on surfaces for months. Targets wounds, lungs, urinary tracts, burns and blood. Treated with carbapenams, colistin and ampicillin.

Citrobacter

Gram -, rod, Enterobacteriaceae found in the soil, water and large intestine. Causes UTIs and opportunistic bacteremia

Serratia marcescens

Gram -, rod, Enterobacteriaceae found in the soil, water or intestine. Causes pneumonia in alcoholics Found in burn and wound infections Fatal septicemia and meningitis

Enterobacter

Gram -, rod, Enterobacteriaceae, commonly found in soil, sewage and dairy. Common cause of UTIs and found in/on surgical wounds, cerebrospinal fluid, blood and sputum.

Escherichia coli

Gram -, rod, Enterobacteriaceae, coliform (ferments lactose), ferments glucose, oxidase nevative, flagellated Used most often as an indicator of fecal contamination in water or food. Also used in scientific studies; genetic recombination. Cause of most UTIs Pathogenic strains lead to severe diarrhea Most common aerobic bacterium in the gastrointestinal tract.

Klebsiella pneumoniae

Gram -, rod, Enterobacteriaceae, large capsule inhabitant of the human respiratory tract. Causes nosocomial pneumonia, meningitis, bacteremia, UTIs and wound infections.

Burkholderia cepacia

Gram -, rod, aerobic ecologically acts as an antifungal for plants as well as in biodegradation of toxic substances. Potential for opportunistic infections of the respiratory tract, urinary tract and the skin.

Burkholderia pseudomallei

Gram -, rod, aerobic is found in the soil and tropical waters. Often acquired through puncture wounds or inhalation from the environment. Causes skin nodules, fever and muscle aches. Chronic infections can become septicemia, shock and abscesses in organs

Haemophilus

Gram -, rod, encapsulated Some species are microflora of the vagina and respiratory tract.

Bordatella pertussus

Gram -, rod, encapsulated, aerobic, oxidase positive, Causative agent of whooping cough, obtained through droplets. Virulence Factors: Adhesion molecules that bind to respiratory cells Toxins that destroy and dislodge cells leading to buildup of fluid and airway blockage. Disease Stages: Catarrhal Stage - nasal drainage, congestion, sneezing and coughing. Paroxymal Stage - persistent coughing with short bursts that create the "whoop" noise. Treatment - with azithromycin and clarithromycin. Prevention - DTaP vaccine containing acellular material

Yersinia pestis

Gram -, rod, encapsulated, stain darker at the ends giving a safety pin appearence causative agent of bubonic plague, virulence factors: coagulase, exotoxins (murine), endotoxin, capsule, envelope protein Vectors: flea, reservoir: small rodents, Human to human transmission has not been reported since 1924. Sylvatic Plague - acquired through wild animals Urban Plague - acquired from semidomestic animals.

Salmonella typhi

Gram -, rod, flagellated, Typhoid Fever is caused by Salmonella typhi Acquired through fecal - oral contamination Bacilli adhere to small intestine mucosa, invade the cells and cause septicemia. The cells travel to the lymph nodes, liver and spleen. Symptoms: Fever, abdominal pain, diarrhea/constipation, intestinal ulcers, nodule or abscesses in liver or urinary tract. Treatment: Ciprofloxacin or ceftriaxone.

Moraxella catarrhalis

Gram -, strictly aerobe, diplococci, or short plump rods, motile, formerly Branhamella catarrhalis, Weakly pathogenic, cause ear infections or conjunctivitis. Also associated with meningitis, endocarditis, otitis media, bronchopulmonary infections and neonatal conjunctivitis.

Enterobacteriaceae

Gram negative bacilli commonly found in the large intestine. Normal flora or pathogens associated with diarrheal illness. Common Characteristics: Glucose fermentation Nitrate reduction Oxidase-negative Flagellated (not Shigella or Klebsiella) Regular, straight rods Antigenic structures are usually identified by serotyping with antibodies: Flagellar Antigen (H antigen) - not in all species Capsular Antigen (K antigen) - not in all species Somatic/Cell Wall Antigen (O antigen) - in all species

Francisella tularensis

Gram negative, rod bacteria Causative agent of tularemia or "rabbit fever" Zoonotic disease Cannot be transferred from human to human Spreads in macrophages Symptoms include headache, backache, fever, chills and malaise. Severe symptoms are ulcerative lesions, swollen lymph nodes, conjunctiva inflammation, sore throat, intestinal disruption and pulmonary symptoms.

Brucella

Gram negative, rod bacteria Causes Brucellosis-obtained through contact with animals and animal products as well as contact with contaminated urine, blood and placenta. Portal of entry is through damaged skin or the digestive tract, respiratory tract and eye. Organism survives within the macrophage and is carried to liver, spleen, bone marrow and kidney. Prevention: Animal vaccination, quarantining and pasteurization.

Pseudomonas aeruginosa

Gram negative, rod bacteria, from human, environmental, and animal sources. Strong oxidase positive reaction, produces pyocyanin (blue-green, water-soluble pigment), Has a grape like smell. Ubiquitous and loves water. Serious opportunistic and nosocomial pathogen. Associated with wounds (burns), premature births, and pneumonia (especially in cystic fibrosis patients). Virulence Factors: Slime layers, Enzymes to degrade host tissue, Exotoxin Disease Manifestations: Healthy individuals develop skin rashes, UTI and external ear infections. Contact lens wearers develop eye ulcers. Immunocompromised individuals can develop endocarditis, meningitis and bronchopneumonia. Pulmonary biofilms in Cystic Fibrosis patients. Treatment: Third generation cephalosporins, aminoglycosides, polymyxin and quinolones.

Staphylococcus species

Gram positive cocci in a cluster Non-spore forming, non-motile Facultative anaerobes Catalase positive

Gastroenteritis

Growth of C. perfringens in animal flesh and vegetables Improper heating of food will not kill spores Cells release enterotoxin in small intestine Cause abdominal pain, diarrhea, nausea for 8 to 16 hours (up to 24)

Biochemical/Phenotypic Identification

Identification method that uses morphology, arrangement, presence of surface appendages, growth, pigments, odor, and motility to identify microorganisms. Tests can include selective and differential media, sugar fermentation, amino acid usage, gas production (O2 and H2S), and gas usage

Pseudomonas

Opportunistic, nosocomial, gram-negative, bacilli, strict aerobe that causes infection primarily in patients with lowered host defenses Found in soil, seawater and fresh water. Monotrichous flagellum Agent of bioremediation Common contaminant of homes and labs

Enterohemorrhagic E. coli

Pathogenic E. coli strain E. coli O157:H7 causes hemorrhagic colitis and can lead to hemolytic uremic syndrome (HUS) and damage the kidneys. Fuses with host cell membrane Secretes Shiga toxin directly into host cell Symptoms of fever, abdominal pain, bloody diarrhea and gastroenteritis. EHEC Outbreaks: Associated with many foods including ground beef/hamburgers, cheese, meats, spinach and other greens. 1993 Jack in the Box Mandatory development of HACCP plans Treatments Antibiotics in early stages Anti-diarrheal medications Pepto-Bismol

Enteroinvasive E. coli

Pathogenic E. coli strain cells invade the mucosal cells of the small intestine and cause inflammation and ulcers in the intestine.

Enteropathogenic E. coli

Pathogenic E. coli strain pathogenesis is not very well understood, but this strain of bacteria is linked with a wasting form of diarrhea in infants.

Enterotoxigenic E. coli

Pathogenic E. coli strain produces two exotoxins that cause severe diarrheal illness. Heat-labile (HL) toxin and heat-stable (HS) toxin stimulate the loss of fluids in the intestine and therefore cause diarrhea. Cause of "Montezuma's Revenge"

Pulmonary Anthrax

Spores are inhaled Macrophages engulf spores and carry them to lymph nodes Germinate and secrete exotoxin Cause capillary thrombosis, cardiovascular shock and death.

Causitive agents of menengitis

Streptococcus agalactiae, Streptococcus pneumoniae (most common cause), Nesseria meningitidis (second most common cause), Moraxella catarrhalis, Pseudomonas aeruginosa, Haemophilus influenzae, Klebsiella pneumoniae, Serratia marcescens

Tetanus and Botulism

Tetanus is caused by Clostridium tetani. Its main virulence factor is tetanospasmin neurotoxin. Tetanospasmin binds to neurons and blocks the release of neurotransmitter that causes muscle relaxation (GABA). It causes uncontrollable contraction of muscles, including opposing muscles. Death occurs due to uncontrollable contraction of respiratory muscles. Botulism is caused by Clostridium botulinum. Botulinum toxin is the most potent and dangerous toxin known. Botulinum toxin inhibits the release of the neurotransmitter acetylcholine, thereby inhibiting muscle contraction. Results in "flaccid paralysis." Symptoms begin as double vision, difficulty swallowing and dizziness. Death occurs due to uncontrollable relaxation of respiratory muscles.

Enteric Yersinia

Yersinia enterolitica and Yersinia pseudotuberculosis both can invade intestinal mucosa and cause severe abdominal pain. The infection mimics appendicitis.

Endotoxin

component of all Gram negative cell walls also known as lipopolysaccharide Causes symptoms of shock including fever, chills, muscle pain, changes in blood pressure.

Enterobacteriaceae Noncoliforms

do not ferment lactose or ferment it slowly and are either pathogens or microflora. Proteus, Morganella, Edwardsiella, Providencia

Enterobacteriaceae Coliforms

ferment lactose rapidly and include normal gram negative flora. E. coli, Enterobacter, Serratia, Klebsiella, Citrobacter Used as a measure of water contamination

Specimen collection

getting samples to test for microorganisms such as urine, blood, CSF, sputum, skin, vaginal and surgical swabs. Must follow aseptic technique and keep sterile stuff sterile.

Selective Media

inhibits growth of some organisms and supports others

Nocardia species

long slender branching, gram positive, filaments, rods, and coccal forms, aerial filaments produced in culture, saprophytes in soil and on decaying vegetation, cause opportunistic infections associated with immunosuppression or following a heavy challenge Most infections are pulmonary and can cause pneumonia or lung nodules/abscesses Nocardia brasiliensis - pulmonary pathogen Nocardia asteroides and Nocardia caviae are opportunists

Genetic testing, Immunology, Biochemical/Phenotype tests

methods of identification

Filamentous Bacteria

non-motile rods that look like fungal hyphae. May stain gram positive, may be acid fast.

Brucellosis

obtained through contact with animals and animal products as well as contact with contaminated urine, blood and placenta. Symptoms of Brucellosis: Fluctuating fever Chills Sweating Headache Muscle pain/weakness Weight loss

Leprosy

progressive skin and nerve disease that leads to disfigurement. Small, spotty lesions on trunk and extremities Wasting of muscles, loss of control Tuberculoid Leprosy - asymmetrical, shallow skin lesions. Fewer complications, easier to treat. Lepromatous Leprosy -face folds, secondary infections, kidney and respiratory failure. Borderline Leprosy - patient may progress or regress either way.

Differential Media

provides a "result" based on growth in/on media

Hemolysis

useful in identification of Strepococcus species Toxins partially, fully, or do not lyse red blood cells Alpha Hemolysis- partial lysis, turns media green Beta Hemolysis- total, media turns clear Gamma Hemolysis- no lysis