Fastidious and Unusual Gram Negative Bacilli (Part 2)

what bacteria infects humans by the bite or scratch of a domestic dog or cat?

pasturella multocida

what bacteria is associated with the following:

• infection develops at site of lesion, usually within 24 hours with or without fever, vomiting, and diarrhea

• diffuse cellulitis with defined erythematous border: culture the expressed pus

• most common cause of infected dog or cat bite

• sepsis and pneumonia are rare, but can be fatal

pasturella multocida

what is the causative agent of tularemia?

francisella tularensis

what bacteria is transmitted in the following ways:

• handling infected animals

  • enters through cracks in skin or mucous membranes

  • “rabbit fever” because occur in butchering of rabbits by hunters

• animal bites

• bites from blood sucking insects: ticks and deerflies (US), mosquitos (europe)

• ingestion of contaminated food or water (cook rabbit meat!)

• inhalation of aerosols

francisella tularensis

which tularemia exposure site is described below:

• most common = ulceroglandular

• local papule at inoculation site → necrotic and ulcerative → subsequent lymphadenopathy of regional lymph nodes

skin

what condition always begins with acute onset of fever, chills, and malaise?

tularemia

what BSL is required for cultures of tularemia?

BSL3

glucose-cysteine blood agar are recommended for cultures for which condition?

tularemia

tularemia is usually identified with DFA or direct agglutination tests. true or false?

true

biochemical testing is not recommended for tularemia because it increases the risk of lab acquired infection. true or false?

true

what bacteria is described below:

• aquatic bacteria: present in lakes, river, soil, mud

• can be found in wide variety of manmade water systems: air conditioning, cooling towers, humidifiers, whirlpool paths, showers, fountains, misters

legionella

what bacteria appears to be relatively resistant to chlorine?

legionella

what bacteria are parasites of protozoa including many species of amoeba?

legionella

most legionella infections are caused by which species?

legionella pneumophilia serogroup 1

which legionella species demonstrates acid-fastness in sputum and tissue?

legionella micadadei

what bacterial genus is described below:

• stains poorly, if at all

• silver impregnation stains (dieterle stain)

• flagella may be present as most are motile

legionella

which legionella species may stain weakly acid fast but loses this quality when repeatedly subcultured?

legionella micdadei

legionella species do not grow on routine media. true or false?

true

what bacterial genus requires a medium that contains amino acids supplemented with L-cysteine and a source of ferric irons?

legionella

the following media is best for growing which bacterial genus?

• BCYE (buffered charcoal yeast extract): non selective

• BCYE-alpha, BCYE with PAC, BCYE with PAV, BMPA-alpha: selective; it contains antibiotics (polymyxin B, anisomycin, cefamandole, vancomycin) - inhibits growth of normal flora

• BCYE-alpha, modified Wadowsky-Yee (aka BCYE differential) is selective and differential; contains antibiotics, glycine (inhibits GNR), bromthymol blue, brocresol purple. colony color varies with species

legionella

____ is inhibited by sodium so saline should not be used for transport (sterile water can be used instead to keep specimens moist).

legionella

B. pertussis, Brucella species, and F. tularensis may also grow on ____ media.

BCYE

what bacterial genus is described below:

• grayish white-blue green ground glass colonies

  • as the colonies age they may be blue-white, yellow-green, or red (depending on the species)

• biochemically inert

  • do not ferment carbohydrates or reduce nitrate

• weak catalase and oxidase positive

legionella

a legionella ____ test should be performed on bacteria that grow on BCYE-alpha.

DFA

a DNA probe can be used to identify which bacterial genus.

legionella

which test is described below:

• commercially available radioimmunoassay detects L. pneumophilia serogroup antigen 1

  • very sensitive and specific

    • can detect antigen in some patients 3 days after illness presentation

    • a positive result may not indicate active disease: some patients excrete L. pneumophilia antigen for a year after infection

urine antigen test

legionella is spread through contaminated water aerosolized and spread either directly (splashing, misting) or through the duct system. NO person to person spread has been documented. true or false?

true

which disease by legionella is described below:

• discovered as a cause of outbreak of pneumonia in men attending an American legion convention through air conditioning system

• most severe form of legionellosis: toxic pneumonia

• initial Sx:

  • myalgia and headache → rapidly rising fever

• later Sx:

  • dry to productive cough

  • chills

  • pleuritic chest pain

  • vomiting, diarrhea

  • confusion, delirium

  • pulmonary infiltrates

  • abnormal liver function tests

• severe cases: patient becomes progressively ill and toxic over the first 3-6 days and the disease terminates in shock, respiratory failure, or both

legionnaire’s disease

which disease by legionella is described below:

• milder than legionnaire’s disease

• self-limiting

  • mortality rate = 0%

• Sx:

  • flulike symptoms (fever and myalgia)

  • 50% have dry cough

  • no pneumonia

• disease does not progress, but recovery usually begins after 2-5 days

• much more common than legionnaire’s disease

pontiac fever

what bacteria is described below:

• pleomorphic gram negative coccobacilli

  • often stains gram variable to gram negative

• non-motile, facultative anaerobe

• resides in vagina (50-70% of women)

  • low numbers, considered normal flora

gardnerella vaginalis

gardnerella vaginalis is catalase ____.

negative

what bacteria resembles gardnerella vaginalis in the sense that it is also normal flora of the vagina and catalase negative, but can be differentiated by a gram stain?

lactobacillus

the following conditions are linked to which bacteria:

• bacterial vaginosis (BV)

• UTIs

• PID

• post partum sepsis which may infect the newborn

gardnerella vaginalis

gardnerella vaginalis is a marker for which condition?

BV

what condition is described below

• abnormal vaginal flora with foul-smelling vaginal discharge

• # of lactobacillus is reduced (required to keep pH low in vaginas)

• other bacteria raise the vaginal pH through production of amines

BV

the following bacteria are also associated with ____:

• mycoplasma hominis

• ureaplasma urelyticum

• bacteroides species

• prevotella species

• mobiluncus species

• peptostreptococcus species

BV

what condition can lead to UTIs, PID, endometritis, amnionitis, (inflammation of membrane surrounding fetus), premature labor, postpartum sepsis, and neonatal sepsis?

BV

BV rarely causes disease in men. true or false?

true

when making a clinical diagnosis of ____ (3 out of the 4 must be present):

• discharge is watery, grayish-white

  • homogenous, noninflammatory, and adheres to vaginal wall

• vaginal pH >4.5

  • pH paper can be used to determine pH of vaginal fluid

• positive “whiff” or “sniff” test

  • mix vaginal fluid with 10% KOH on glass slide

  • a fishlike amine smell = positive result

    • KOH enhances odor of amines produced by gardnerella vaginalis and anaerobic bacteria)

• presence of “clue cells”

  • squamous epithelial cells covered with bacteria

  • seen on wet mount or gram stained smear of vaginal discharge

BV

in nugent scoring, a score of ____ is indicative of bacterial vaginosis.

>7

the following bacteria are used in the grading of ____ to test for bacterial vaginosis where each column is given a score based on the quantity of the specific morphology seen under HPF (1000x) and all 3 scores are added together:

• GPR (lactobacillus)

• small pleomorphic GNRs (bacteroides/gardnerella)

• curved GNRs (mobiluncus)

nugent scoring

culturing gardnerella vaginalis is not recommended for diagnosis of BV because many normal healthy women carry it. true or false?

true

gardnerella vaginalis can grow on BAP, CHOC, CNA, but not ____.

MAC

human blood tween bilayer (HBT) medium and vaginalis agar (V agar) can be used for which bacteria?

gardnerella vaginalis

HBT and V agar contain human blood and will make gardnerella vaginalis appear _____.

beta-hemolytic

gardnerella vaginalis is non-hemolytic on sheep blood agar (BAP). true or false?

true

the following bacteria are part of the ____ group:

• H = Haemophilus species

• A = Aggregatibacter (actinobacilllus) actinomycetemcomitans

• C = Cardiobacterium hominis

• E = Eikenella corrodens

• K = Kingella species

HACEK

HACEK organisms share an enhanced ability to produce ____ infections.

endocardial

HACEK organisms are part of the normal ____ flora.

oral

what bacteria is associated with endocarditis and gum disease?

aggregatibacter actinomycetemcomitans

what bacteria is described below:

• growth

  • grows well on SBA and CHOC, no growth on MAC

  • grow colonies that show star-like centers

• most are catalase and oxidase positive

aggregatibacter (actinobacillus) actinomycetemcomitans

aggregatibacter actinomycetemcomitans is normal oral flora of ____.

humans

actinobacillus species are found mostly as oral flora of ____.

animals

what bacteria is described below:

• found as normal flora in humans in the upper respiratory tract, possibly the GI and genital tracts

• gram stain: short chains, pairs, rosettes of irregularly staining bacilli with bulbous ends

• facultative anaerobe and prefers humidified, CO2

• biochemicals

  • oxidase positive

  • catalase negative

  • weakly indole positive

• mainly associated with endocarditis

cardiobacterium hominis

what bacteria is described below:

• approximately 50% of strains will corrode or pit the agar surface

• produces a bleach-like odor

• colonies are small, flat, spreading, and often yellowish

eikenella corrodens

what bacteria is associated with the following:

• HUMAN bite wounds (normal flora of mouth and upper respiratory tract), abscesses of the normal cavity, endocarditis, osteomyelitis

• infections with this bacteria are often mixed

eikenella corrodens

which species of kingella is described below:

• usually occur in young children (colonizes their throat)

• bacteremia, wound infections, septic arthritis

• infections in adults generally limited to immunocompromised

kingella kingae

which species of kingella is described below:

• rarely causes disease

• most often associated with endocarditis

• can be confused with neisseria gonorrhoeae because both can grow on gonococcal selective media, acidify glucose, oxidase positive, and are hydroxyprolylaminopeptidase positive

kingella denitrificans

kingella denitrificans or neisseria gonorrrhoeae:

• nitrate positive

• catalase negative

kingella denitrificans

kingella denitrificans or neisseria gonorrhoeae:

• nitrate negative

• catalase positive

neisseria gonorrhoeae

streptobacillus moniliformis and spirillum minus/minor are associated with ____ bite fever.

rat

what bacteria is associated with the following:

• rat bite fever

  • infected via rat bite or possible direct handling/contact with rats

  • normal flora of upper respiratory tract of wild/lab rats; rare to isolate from other animals (e.g., mice, guinea pigs, gerbils)

• haverhill fever

  • acquired by ingestion (e.g., contaminated milk)

• both infections have similar clinical manifestations

  • acute onset of chills, fever (can last weeks → months), headaches, vomiting, often severe joint pains

  • rash develops on palms and soles of feet and other extremities

streptobacillus moniliformis

when culturing ____, alternative methods should be considered because the organism will not grow in SPS (found in blood culture bottles).

streptobacillus moniliformis

when culturing ____, collect blood, mix with equal volume 2.5% citrate (prevent clotting) and inoculate into brain-heart infusion cysteine broth supplemented with Panmade (ox liver digest) or use commercially available fastidious anaerobe broth without SPS or thiol broth.

streptobacillus moniliformis

streptobacillus moniliformis is nonmotile and catalase, oxidase, nitrate, indole, urea, and lysine decarboxylase ____.

negative

what bacteria is described below:

• gram negative, helical, strictly aerobic

• has never been grown in culture

• other causative agent for rat bite fever = sodoku

• arthritis rarely seen

• swollen lymph nodes are prominent

spirillum minus/minor

spirillum minus/minor or streptobacillus moniliformis: incubation period of 12 hours?

streptobacillus moniliformis

spirillum minus/minor or streptobacillus moniliformis: incubation period of 1-4 weeks?

spirillum minus/minor

the progression of illness by ____ involves the following:

• bite → wound heals spontaneously but 1-4 weeks later reulcerates to form a granulomatous lesion at the same time patient develops:

  • fever, headache, generalized, blotchy, purplish, maculopapular rash

spirillum minus/minor