bacte lec - miscellaneous Gram-negative bacilli

Capnocytophaga

→ Normal microbiota of the oral cavity of humans
→ Causes septicemia in patients with neutropenia
→ Fastidious, facultative anaerobe
→ Thin and often fusiform (pointed ends) resembling Fusobacterium spp.
→ No flagella but can produce gliding motility on solid surfaces

Ferment sucrose, glucose, maltose, and lactose

Capnocytophaga ferments

Indole negative

Capnocytophaga indole ________

→ Blood cultures from patients who have neutropenia with oral ulcers (source of the Capnocytophaga)
→ Soft tissue infections
→ Peritonitis
→ Endocarditis

Capnocytophaga common site of clinical isolation

Capnocytophaga ocracea

Most common isolate or capnocytophaga

Capnocytophaga canimorsus
Capnocytophaga cynodegmi

→ Normal inhabitants of the oral cavity of dogs and cats
→ Infection from dog or cat bite (capnocytophaga)

Legionella

→ Non-spore forming, thin, gram-negative bacilli
→ Faintly staining
→ Found in the environment especially water
→ Tolerate chlorine concentrations of 3 mg/L
Transmission: exposure to contaminated water (faucets, showerheads, public fountains, aircon)
Reservoirs: Hot water systems, cooling towers, and evaporative condensers are major reservoirs

Legionella pneumophila

First recognized to cause human disease during an epidemic of pneumonia that occurred among members of the Pennsylvania American Legion who had gathered in Philadelphia to celebrate the 1976 bicentennial caused by

intracellular pathogens

Legionella ability to exist as ___________ (amebae and mammalian cells)

phagolysosome

Legionella survive inside phagosomes, prevent the formation of ___________

20C to 43C; 40C to 60C

Legionella The ability to multiply over the temperature range of ______and survive for varying periods at ________

Legionnaire's Disease

→ Febrile disease with pneumonia
→ Predominant manifestation: pneumonia

Legionnaire's Disease

Incubation and Symptoms of ___________
→ Nonproductive cough
→ Fever
→ Headache
→ Myalgia
→ Sputum may be bloody or purulent
→ May lead to extrapulmonary infection

2-10 days

Legionnaire's Disease incubation period

Pontiac Fever

→ Influenza-like febrile disease
→ Non-pneumonic form of legionellosis
→ inhalation of bacterial toxins or an acute allergic reaction
to the bacteria
→ previously healthy individuals who complain of flulike symptoms of fever, headache, and myalgia that last 2 to 5 days and then subside without medical intervention

2 days

Pontiac Fever incubation period

sputum, bronchoalveolar lavage, and bronchial washings

Specimen for culture and direct examination: of legionella

suspicion is high

Specimen for culture and direct examination of legionella: Other tissues or fluids, such as pleural fluid, are generally acceptable when____________

−70° C

Legionella: Freeze specimens at _________ if processing will be delayed for several days

Diff-Quik and Giemsa

Other stains for legionella

BCYE (Buffered charcoal yeast extract) agar with L- cysteine

Best culture media for Legionella isolation

Legionella on BCYE (Buffered charcoal yeast extract) agar with L- cysteine

→ Colonies appear as grayish white or blue-green, convex, and glistening, measuring approximately 2 to 4 mm in diameter
→ Central portion of young colonies has a "ground-glass" appearance, light gray and granular
→ The periphery of the colony has pink or light blue or bottle green bands with a furrowed appearance

polymyxin B, anisomycin, and either vancomycin or cefamandole

Selective BCYE agar contains:

35C; CO2

Legionella is incubated at ______in air; increased ______ can enhance the growth of some of the more fastidious species

1:10 0.2N potassium chloride - hydrochloric acid

Legionella: Aliquot of the specimen is first diluted ________ with

complement antibodies and antimicrobial agent

Specimens from normally sterile sites should be diluted 1:10 in tryptic soy broth or distilled water (Done in order to dilute microbial inhibitors such as _________ and ___________)

Bordetella pertussis
Bordetella parapertussis

2 species of bordetella

Whooping cough or pertussis

→ Transmission occurs person to person through inhalation of respiratory droplets
→ Highly contagious, acute infection of the upper respiratory tract
→ Caused by Bordetella pertussis

Catarrhal stage of pertussis

• Symptoms are the same as for a mild cold with a runny nose and mild cough
• Lasts several weeks

Paroxysmal stage of pertussis

→ Severe and violent coughing
→ Vomiting and "whooping" (the result of air rapidly inspired into the lungs past the swollen glottis)
→ Lasts 1-4 weeks

15 to 25

Pertussis: _________ paroxysmal coughing episodes can occur in 24 hours

Adhesion (auto transporters)
Toxicity
Overcome host defenses

Major Virulence Determinants of Bordetella pertussis

Nasopharyngeal aspirates or a nasopharyngeal swab

Bordetella specimen

calcium-alginate or Dacron on a wire handle

Nasopharyngeal aspirates or a nasopharyngeal swab collected by __________

throat, sputum, or anterior nose

Bordetella : Specimens obtained from the __________ are not accepted because these sites are not aligned with ciliated epithelium.

→ Half-strength Regan-Lowe agar
→ Cold casein hydrolysate medium
→ Casamino acid broth

Transport media that can be used for bordatella

→ Bordet-Gengou
→ Modified Jones-Kendrick charcoal
→ Regan-Lowe
→ Stainer-Scholte

Selective media for isolation of Bordetella pertussis and parapertussis

Bordet-Gengou

Potato infusion agar with glycerol and sheep blood with methicillin or cephalexin (short shelf-life)

Cephalexin

is superior to methicillin and penicillin for inhibiting normal respiratory flora

Modified Jones-Kendrick charcoal

→ Charcoal agar with yeast extract, starch, and 40 ug cephalexin
→ 2- to-3-month shelf-life but inferior to Regan-Lowe agar

Regan-Lowe

→ Best for the recovery of B. pertussis from nasopharyngeal swabs
→ Charcoal agar with 10% horse blood and cephalexin
→ 4 to 8- week-shelf-life

Stainer-Scholte

→ Synthetic agar lacking blood products

"mercury drops"

Young colonies of B. pertussis and B. parapertussis:

Erythromycin

Drug of choice for pertussis

Catalase +
Oxidase +

B. Pertussis positive tests

Catalase +
Urease + in 24 hours
Blood agar +
Mac agar V

Bordetella Parapertussis Positive tests

Zoonosis

disease that humans acquire from exposure to infected animals

Pasteurella

Normal flora of oral cavity in birds and mammals

Pasteurella multocida

→ Commensal found in nasopharynx and gastrointestinal tract of wild and domestic animals
→ Potential upper respiratory commensal in humans having extensive occupational exposure to animals

Bite or scratch from variety of veterinary hosts (usually feline or canine)
Less commonly, infections may occur without history of animal exposure
Infections may be associated with non- bite exposure to animals

Pasteurella multocida (mode of transmission)

Pasteurella canis

Dogs pasteurella
• Gram-negative coccobacilli
• Non-motile
• Facultative anaerobic coccobacilli
• Bipolar staining: "Safety pin" appearance

SBA and CHOC agar

Pasteurella culture medias

Pasteurella

• grayish colonies
• nonhemolytic colonies on SBA that may appear mucoid after 24 hours of incubation at 37° C
• production of a narrow green-to-brown halo around the colony after 48 hours

Oral cavities of healthy domestic dogs, cats, and other animals

Pasteurella multocida normal habitat

zoonotic disease

Brucella is the causative agent for __________

Brucella

→ Small, facultative, intracellular, nonmotile, aerobic,
gram-negative coccobacilli or short rods
→ Capable of survival for extended periods
→ A cause of devastating economic loss among domestic livestock

Ingestion of infected unpasteurized animal milk products

most common means of transmission for brucellosis

→ Inhalation of infected aerosolized particles
→ Direct contact with infected animal parts through rupture of skin and mucous membranes
→ Accidental inoculation of mucous membranes by aerosolization
→ Systemic, deep-seated disease resulting in various long-term sequelae

Mode of transmission for Brucella

Cattle

Preferred animal host for Brucella abortus

Sheep or goats

Preferred animal host for Brucella melitensis

Swine

Preferred animal host for brucella suis

Dogs

Preferred animal host for Brucella canis

Desert and wood rats

Preferred animal host for Brucella neotomae

Rams

Preferred animal host for brucella ovis

Blood
Blood marrow
Cerebrospinal fluid (CSF)
Pleural and synovial fluids
Urine
Abscesses
Other tissues

Brucella Specimen: 7

blood agar and chocolate agar

Brucella culture media

Brucella agar or infusion base

Brucella: recommended for specimen types other than blood

Brucella

→ Colonies appear small, convex, smooth, translucent, nonhemolytic, and slightly yellow and opalescent after at least 48 hours of incubation
→ Small coccobacilli that resemble fine grains of sand

(+) Oxidase
(+) Catalase
(+) Urease

Brucella positive tests

rapidity with which an organism hydrolyzes urea, relative ability to produce H2S, requirements for CO2, & its susceptibility to aniline dyes: thionine and fuchsin

Brucella species are differentiated by the

Francisella

CHARACTERISTICS
Facultative
• Intracellular pathogens
• Nonmotile
• Non-spore forming
• Strict aerobes

rabbit fever, deerfly fever, lemming fever, and water rat trappers' disease

Tularemia infection is also called

Francisella tularensis

→ Causes human and animal tularemia
→ wild rodents, rabbits, beavers, and muskrats in North America
→ Humans become infected by handling the carcasses or skin of infected animals
→ inhaling infective aerosols or ingesting contaminated water

tularemia

is one of the most common laboratory-acquired
infections

Ulceroglandular

common; ulcer and lymphadenopathy; rarely fatal

Glandular

common; lymphadenopathy; rarely fatal

Oculoglandular

conjunctivitis; lymphadenopathy

Oropharyngeal

ulceration in the oropharynx

Systemic (typhoidal) tularemia

→ acute illness with septicemia; 30% to 60% mortality rate;
→ no ulcer or lymphadenopathy

Pneumonic tularemia

acquired by inhalation of infectious aerosols or by dissemination from the bloodstream; pneumonia; most serious form of tularemia

Scrapings from infected ulcers, lymph node biopsies, and sputum

Francisella tularensis specimen

whole blood

F. tularensis ________ is acceptable but false-negative results
may occur during early stages of disease

serum

F. tularensis: specimen for ________early stage of the disease, convalescence

Amie's transport medium containing charcoal

Francisella tularensis transport medium for swab specimen

cysteine, cystine, thiosulfate or IsoVitaleX

sulfhydryl compounds

Gardnerella vaginalis

→ part of the anorectal flora of healthy adults of both sexes,
as well as of children
→ part of the endogenous vaginal flora of women of
reproductive age
→ Causes bacterial vaginosis

Nonmotile

Gardnerella vaginalis (motility)

Gardnerella vaginalis

Colonies are small and exhibit beta-hemolysis on media containing rabbit or human blood

clue cells

epithelial cells covered with bacteria on the cell margins

Fishy amine odor after addition of 10% potassium
hydroxide (KOH)

Gardnerella vaginalis odor

Streptobacillus

→ facultatively anaerobic, fermentative, nonencapsulated, and
nonmotile pleomorphic gram-negative rod
→ string-of-beads appearance

Streptobacillus moniliformis

→ indigenous flora in the upper respiratory tract of wild and
laboratory rodents
INFECTION CAUSED BY
→ rodent bites, ingestion of contaminated food, or traumatic
injury

Blood, Joint fluid, Abscess material

Streptobacillus moniliformis (specimen)

5% to 10% CO2

Streptobacillus moniliformis Incubated at 35C in a humid environment containing an atmosphere of _____________

✨PASAR BACTERIOLOGY✨

✨MANIFESTING✨