Micro solo 7

General characteristics of Haemophilus species

X-factor, V factor: nicotine adenine dibucleotide (NAD) or NAD phosphate, chocolate agar is best to grow because it has both X and V, can grow on BAP when a satellite phenomenon can occur when Staph aureus grows and lyses the blood cells releasing X and V

Haemophilus ducreyi epidemiology

not part of normal human flora, mode of transmission is through person-to-person typically through sexual contact (STI)

Haemophilus ducreyi spectrum of disease

Chancord: genital legions progress from tender papules to painful ulcers

Haemophilus ducreyi identification

colonies can be pushed intact across the agar surface (hockey puck), requires X factor but does not need V to grow

Haemophilus haemolyticus habitat

normal human flora of the upper respiratory tract

Haemophilus haemolyticus identification

colonies resemble Haemophilus influenzae on CAP except will be beta hemolytic on rabbit or horse blood agar, requires both X and V factor for growth, catalase positive

Haemophilus influenzae epidemiology

normal human flora of the upper respiratory tract, mode of transmission is respiratory droplets

Haemophilus influenzae spectrum of disaese

Encapsulated strains: Meningitis, the most serious infections are caused by Haemophilus influenzae type b

Haemophilus influenzae identification

encapsulated strains are larger and more mucoid, both types have distinct mouse nest odor, requires X and V factors to grow, non-hemolytic, catalase positive, glucose and xylose fermentation positive

Haemophilus ducreyi drug of choice

Erythromycin

General characteristics of Bartonella species

typically take 12 to 14 days to appear and sometimes up to 45 days, very fastidious, oxidase and catalase negative

Bartonella baciliformis epidemiology

habitat is humans, mode of transmission through sandflies

Bartonella species virulence factors

multiply and persist in the red blood cells

Bartonella baciliformis spectrum of disease

Oroya fever, Carrion’s disease, mortality rate range from 40-90%

Bartonella hensalae epidemiology

habitat: domestic cats, mode of transmission: domestic cat bites or scratches, fleas and ticks

Bartonella henselae spectrum of disease

causes cat scratch disease (CSD), history of animal contact with evidence of a scratch or primary inoculation, negative laboratory studies for other causes of lymphadenopathy, characteristic histopatholgy of the lesion, positive skin test using antigen prepared from heat-treated pus collected from another patients lesion

Bartonella quintana epidemiology

habitat: humans, mode of transmission: human body louse and fleas

Bartonella quintana spectrum of disease

causes trench fever: influenza like headache and bone pain and rash

Bartonella species identification

white “Cauliflower-like” colony that pits the agar, slightly curved rod, oxidase urease nitrate reductase and catalase negative

Bartonella species antimicrobial susceptibility

results in vitro testing may not correlate with clinical efficacy, recent treatments with azithromycin indicate a successful and quicker result to CSD

Campylobacter species epidemiology

Campylobacter jejuni infections are transmitted by direct contact during preparation and eating of chicken in developed countries

Campylobacter species spectrum of disease

post-infection complications of Campylobacter jejuni have been recognized and include reactive arthritis and reactive arthritis and Guillain-Barre syndrome

Campylobacter species identification

Campy BAP in a microaerophilic condition at 42C up to 72 hours, blood cultures need to be held for up to 2 weeks for detection, oxidase and catalase positive, growth at 42C, Hippurate hydrolysis positive for jejuni all other negative, nitrate reduction positive

Helicobacter pylori epidemiology

primary habitat is the human gastric mucosa

Helicobacter pylori spectrum of disease

produces a protein called Cag A and injects the protein into the gastric epithelial cells, affects host cell gene expression, altering cell structure and interactions with neighboring cells, enabling Helicobacter pylori to invade the gastric epithelium, positive antibody response to CagA protein are at an increased risk for developing both peptic ulcer disease

Helicobacter pylori identification

positive for oxidase, catalase, and urease

Campy jejuni and Helicobacter pylori antimicrobial susceptibility

Erythromycin is the drug of choice for patients with severe gastroenterities with signs os severe dehydration and/or bacteremia, Helicobacter current regimens recommend a tripile drug therapy including: proton pump inhibitor (prilosec or nexium), clarithromycin, Amoxicllin or metronidazole

Legionella pneumophilia general characteristics

they are faintly straining, thin gram negative bacillil, does not grow on routine media and requires a medium supplemented with iron and L-cysteine for growth: the organism utilizes protein instead of carbohydrates for their energy source, Legionella pneumophila dominates the genus as the predominant human pathogen

Legionella pneumophilia epidemiology

widely distributed in the environment, primarily found in aquatic habitats and thrive at water temperatures, survive up to 14 months in water with only a slight loss in viability, air-conditioning unit (man-made facilities where Legionella is), infections are acquired exclusively from environmental sources

Legionella pneumophila viruelence and spectrum of disease

this contributes to the organism’s survival in the environment, Legionnares disease is the main disease state, pontiac fever: mild, self-limited, nonfatal, influenza-like respiratory infection

Legionella pneumophilia identification

because Legionella pneumophila is biochemically inert, specimens suspect are planted to two plates: BCYE with and without L-cyseteine, will only grow on the BCYE with L-cysteine, Direct immunofluoscent antibody can be used on respiratory secretions to test for presence: attach to the organism’s antigens and cause the organism to glow a bright green

General characteristics of Brucella

these organisms are all considered potential agents of bioterrorism

Brucella species epidemiology

these organisms are all considered potential agents of bioterrorism, especially in the mediterranean and Persian gulf countries, can survive in fresh cheese for several months, ingestion of unpasteurized animal milk (most common), laboratory acquired infections, infected animal parts, Brucella abortus: cattle and buffaloes, melitensis: sheep, goats, or camels, suis: swine and a variety or wild animals, canis: dogs

Brucella species spectrum of disease

able to exist both intracellular and extracellular environments, ingested by neutrophils will replicate and cause cell lysis, Brucella melitensis and abortus are most viruelent for humans, causes a condition called brucellosis which is considered a zoonotic infection, symptoms are lymphadenopathy and splenomegaly

Brucella abortus identification

all brucella strains will be catalase positive, urease positive and oxidase positive, differentiated by the rapidity of which the organism hydrolyzes urea and ability to produce H2S, and inhibition to aniline dyes, Brucella abortus does not grow in ambient air, 2 hours for positive urease, H2s produced, inhibited by thionine, not inhibitedby fuchsin

Brucella melitensis identification

2 hours for positive urease, H2s negative, not inhibited by any dyes

Brucella suis identification

15 minutes for a positive urease, H2S is variable, is not inhibited by thionine, inhibited by fuchsin

Brucella canis identification

15 minutes for positive urease, H2S is not produced, is not inhibited by thionine, inhibited by fuchsin, colonies are rough instead of smooth

Brucella antimicrobial susceptibility

patients undergo treatment for around 6 weeks, deoxycycline or tetracycline in combination with streptomycin or rifampin

Bordetella pertussis and parapertussis epidemiology

transmission occurs person-to-person through inhalation of respiratory droplets

Bordetella pertussis and parapertussis spectrum of disease

Pertussis toxin: enters the bloodstream binds to specific receptors , clinical pertussis is usually a disease of children and can be divided into three sysmptomatic stages: catarrahal stage: same as mild cold, paraoxysmal stage: severe and violent coughing increase, “whooping”, convalescent stage: recovering stage

Bordetella pertuissis identification

Bordet-Gengov and Reagan-Lowe media, catalase positive, oxidase positive

Bordetella parapertussis epidemiology

catalase positive, oxidase negative, urease positive (24 hours),

Bordetella species antimicrobial susceptibility

susceptibile to erythromycin

Francsella general characteristics

require cysteine, cystine, or another sulfhydryl and a source of iron for enhanced growth, considered a bioterrorism agent

Francisella tulaernsis epidemiology

agent of human and animal tuleremia, wild rodents, rabbits, beavers, and muskrats in north america, seen in oklahoma

Francisella tularensis virulence factors

humans can be infected by fewer than 50 organisms by either aerosol or cutaneous routes

Francisella tularensis spectrum of disease

Tularemia is recognized worldwide and has also been called raid fever, deer fly fever, and market men’s disease, lesion at site of infection, ulcer-lymph nodes and site of innoculations are enlarged and necrotic, patients become extremely ill, 6 different types: ulceroglandular, glandular, occuloglandular, oropharyngeal, systemic (thyphoidal) tularemia, Pneumonic tularemia

Francisella tularensis identification

subcultures yeild primarily pinpoint colonnies on CAP, grows better on CAp than BAP, oxidase negative, weak catalase positive, detection is longer then 24 hours

Francisella tularensis antimicrobial susceptibility

Streptomycin is the drug of choice

general characteristics of Streptobacilus moniliformis

requires media containing blood, serum, or ascites fluid

Streptobacillus moniliformis epidemiology

natural habitat is the upper respiratory tract of wild and laboratory rats, transmitted by two routes: rat bite and ingestion of contaminated food

Streptobacillus moniliformis spectrum of disease and virulence factors

virulence factors are unknown but is known to spontaneously develop L forms, Bacteria without cell walls, the disease state is called rat-bite fever or Haverhill fever

Streptobacillus moniliformis identification

pleomorphic gram negative rod, growth on BAP can occur after 48 hours, a “fried egg” appearance, acridine orange may be used to confirm, indole negative, catalase negative, oxidase negative, nitrate reduction negative, nonmotile, urea negative, lysine decarboxylase negative, H2S is not produced in TSIA but can ne detected using lead acetate paper

Streptobacullus moniliformis antimicrobial susceptibility

Penicillin is considered the drug of choice

Category A bioterrorism agents

highest priority agents: easily disseminated or transmitted from person to person, result in high mortality rates, cause public panic and social disruption, requires special action for public health preparedness, Bacillus antracis, Clostridium botulinum toxin, Yersinia pestis, Variola major (smallpox), Franiscella tularensis, Ebola

Category B bioterrorism agents

Brucella species, Epsilon toxin of Clostridium perfringens, food safety threats- Salmonella E coli O157:H7 Shigella, Burkholderia mallei and pseudomallei, Chlamydia, Staphylococcal enterotoxin B, water safety threats - Vibrio cholderae