Bacteriology: Enterobacterales Flashcards
How do you interpret gram negative cocci in a gram stain?
you either messed up, there was some other change in cell wall, or the organism stained was not a pathogen
Which G- rods are oxidase negative?
E.coli
Salmonella
Yersinia
Klebsiella
Proteus
What are the main hosts of Escherichia coli?
all animal, birds, fish, etc
What major diseases does E.coli cause?
enteritis, septicemia, cystitis, pyometra, osteomyelitis, mastitis
Who are the main hosts of salmonella?
all animals, birds, reptiles, insects
What major diseases does salmonella cause?
Enteritis, septicemia, abortion
Who are the main hosts of Yersinia?
ruminants, cats, humans
What major diseases does Yersinia cause?
Plague, Enteritis (dysentery)
Who are the main hosts of Klebsiella?
Dogs, cows, horses, mink
What are the major diseases that Klebsiella causes?
Pneumonia, mastitis, endometritis, wound infections
Who are the main hosts of Proteus?
dogs, other species
What major diseases does Proteus cause?
cystitis, otitis externa, wound infections
What are the oxygen requirements of enterobacterales?
facultative anaerobes
Are enterobacterales oxidase positive or negative?
negative
Some enterobacterales are hemolytic except proteus, as they _____
swarm
What two plates do enterobacterales grow on?
MacConkey
Blood agar
Enterobacterales can be divided into 2 groups based on lactose fermentation. Which are positive and which are negative?
positive - e.coli, klebsiella
negative - proteus, salmonella, yersinia
Of the enterobacterales, which are considered good pathogens? What does this mean?
E. coli, salmonella, yersinia
require little host compromise and only a need a few bacteria to cause disease
Where do E.coli come from?
Normal flora from most vertebrates in the lower ileum and large intestine and survive well in environment from forming coliforms
How is E.coli transmitted?
mostly feco-oral but could be inhalation, direct inoculation, ascending infection
What are examples of ascending infection?
cystitis, pyometra, transient in urogenital tract
Explain the significance of E.coli and virulence. What are some specific virulence factors?
not all strains are pathogenic
virulence factors act by
attachment (fimbrae)
avoiding phagocytosis (capsule)
cellular effects (hemolysin and CNF)
systemic effects (endotoxin)
HWhat does the contribution of the virulence factor of E.coli depend on?
site of infection
Explain how E.coli has been incriminated to have caused infectious disease in virtually every tissue and organ system
opportunistic pathogen
How do you diagnose e.coli?
collect samples from sterile site and apply 4 point rule
How do you treat E.coli infections?
there are multiple drug resistant strains so need to do an antibiotic susceptibility test
Ancillary treatment is also necessary
Explain different methods of ancillary therapies
surgery/drainage/debridement
fluid therapy
anti-endotoxin therapies
How do you name Salmonella?
Genus + serotype
Where does Salmonella come from?
NOT NORMAL FLORA
Carrier animals
Environment
How is Salmonella transmitted?
feco-oral
animal species carriers such as reptiles, cattle, horses
recrudescence of carrier
How is Salmonella able to avoid phagocytosis and cause disease?
facultative intracellular parasite
What are the 3 main clinical syndromes that Salmonella causes?
enteritis, septicemia,
How are non-enteric Salmonella infections diagnosed?
collect sample from sterile site
Where does Yersinia come from?
Yersinia pestis - wild rodents are the reservoir
What life cycle is important pertaining to Yersinia?
flea-rodent-flea
How is Yersinia capable of causing disease
facultative intracellular parasite
What are the two main types of Non-enteric Yersinia?
Y pestis
Y pseduotuberculosis
What does Y pseudotuberculosis cause?
sporadic abortion in ruminants
more severe dx including septicemia
What disease does Y pestis cause?
Black death - plague
What species does the Plague effect mostly?
humans and cats
What are the 3 types of the Plague?
bubonic (LN)
Pneumonic (lung)
Septicemic (systemic)
What clinical signs are seen in cats with the Plague?
severe depression
fever
enlarged peripheral LN
How do you diagnose Y.pestis infections?
WITH CAUTION
send aspirates of pus, blood, LNs to specialized lab
report to PH
PCR
How do you treat Y. pestis?
usually euthanasia but can use long course of antibiotics and need complete and total isolation for duration of treatment - treat cat for fleas immediately and lance/flush buboes (LN)
What species of Klebsiella is the most commonly isolated in animals?
K. pneumoniae
Where does Klebsiella come from?
NF
saprophye - sawdust
What specific diseases does Klebsiella cause?
pneumonia, cystitis, mastitis, endometritis, navel ill, nosocomial infection
What two species of Proteus are the most commonly isolated from infections in animals?
P. mirabalis
P. vulgaris
Where does Proteus come from?
NF
Saprophytes
What specific diseases does Proteus cause?
cytstits, otitis externa, prostatitis, wound infections
How do you diagnose Klebsiella and Proteus infections?
isolation from sterile sites using aseptic techniques, apply 4 point rule, repeated cultures if necessary of Proteus
