Microbiology mnmonics

Question 1

YES Some Nasty Killers Have Pretty Big Capsule

Answer 1

Yersinia pestis
E.Coli ( meningeal strains only)
Salmonella typhi

Streptococcus Pneumoniae and Beta Hemolytic Group

Neisseria Meningitidis

Klebsiella Pneumoniae

H.influenzae type b

Pseudomona aeruginosa

Bacillus anthracis

Cryptococcus neoformans

Side Note #1:

For some reason FA and kaplan neglects to mention Staphylococcus Aureus, which has 11 serotypes/strains that have capsule and there should be a correction in that it is not group B streptococci, both beta hemolytic groups A and B produce capsule. Also Campylobacter jejuni has 47 capsular strains. Some other bacteria are partially encapsulated or unfinished or what is called microcapsules that functions and not completely understood. This is the case with Citrobacter (there is development of vaccines against Salmonella due to similar composition of vi polysacharide capsule )and Bordetella pertussis. Also vibrio cholera does have 1 strain (139) that is encapsulated.

Question 2

Some Killers Have Pretty Nice Capsules

Answer 2

Step pneumonia
    klebsiella
    Heamophilus influenzae
    Pseudomonas aeruginosa
    Neisseria meningitidis
    Cryptococcus neoformans

Question 3

Catalase Positive Microorganisms

Answer 3

he classical USMLE question describing a case of Chronic Granulomatous Disease and then asking you what other infection is the patient liable to get.

Of course you should be thinking of all of the catalase positive microorganisms.

Here’s a mnemonic

SPACE

Staphylococci (important not confuse it with streptococci)
Pseudomonas aeroginosa
Aspergillus fumigatus
Candida
Enterobacteriaceae (specially Klebsiella and Serratia both of which can cause pneumonia and UTI)

Worth to remember that none of the anaerobes are Catalase positive

Also some others are Catalase positive

    Nisseria (Gonorrhea & Meningitidis)
    Vibrio
    Nocardia
    Campylobacter & Helicobacter
    Gardnerella vaginalis
    Pseudomonas cepacia
    Mycobacterium Tebeculosis also produce a heat sensitive catalase ( active only in body temperature ) so it become catalase negative at 68.0 "F

Question 4

Pertuss background

Answer 4

Pertussis (whooping cough) is a highly communicable, acute, infectious respiratory disease
caused by Bordetella pertussis. B. pertussisis a small, aerobic, Gram-negative pleomorphic
bacillus (0.2 to 0.5 IJm in diameter). The bacteria are fastidious and difficult to culture and
have an incubation period of 10 to 14 days. B. pertussisproduces multiple antigenic and
biologically active products, including pertussis toxin (PT), filamentous hemagglutinin (FHA),
agglutinogens, adenylate cyclase (AC) toxin, pertactin, fimbriae, tracheal colonization factor,
and tracheal cytotoxin (TCT), which are responsible for the clinical features of pertussis
disease.l,2Two closely related organisms are Bordetella parapertussis, which causes a
pertussis-like syndrome in humans, and Bordetella bronchiseptica, which produces respiratory
tract illness in animals, although it has been occasionally reported in humans, including several
case reports of B. bronchisepticainfection in HIV-infected patients as well as a single case
report of an immunocompetent infant with recurrent pneumonia due to B. bronchiseptica

Question 5

Pertuss I.P

Answer 5

10 to 14 days

apic page 1383

Question 6

The incubation period of pertussis in nonimmunocompromised patients

Answer 6

usually 7 to 10 days,
with a range of 6 to 21 days. Rarely, the incubation period may be as long as 42 days.
APIC page 1386

Question 7

CJD

Answer 7

incubation period ranging from 1.2 to 24.8 years

with a median and mean incubation of 12.4 and 11.8 years, respectfully.

Question 8

Iatrogenic transmission of CJD

Answer 8

Iatrogenic transmission within the healthcare setting can occur when patients are exposed
directly to infectious prion materials via inadequately sterilized neurosurgical equipment,
contaminated lyophilized dura mater, corneal transplants, cortical electroencephalogram
electrodes, and injections of cadaveric pituitary-derived growth hormone.

Question 9

Kaplan criteria to determine if an outbreak was possibly caused by the
norovirus.

Answer 9

There are four components of the Kaplan criteria: (1) a mean (or median) illness
duration of 12 to 60 hours, (2) a mean (or median) incubation period of 24 to 48 hours, (3)
more than 50 percent of people with vomiting, and (4) no bacterial agent found in stool
culture. When all four are present, it is very likely that the outbreak was caused by norovirus.
However, about 30 percent of norovirus outbreaks do not meet these criteria . If the criteria are
not met, it does not mean that outbreak was not caused by norovirus.

Question 10

HSV-2, the incubation period

Answer 10

after sexual contact can range from 3 to 14 days but usually

appears as vesicular lesions and denuded areas of genital mucous membranes with in 1 week.

Question 11

incubation period of HIV

Answer 11

In the majority of patients, the incubation period lasts 2

to 4 weeks but in some patients may last for several months.

Question 12

incubation period of Foodborne Illnesses

Answer 12

See APIC pages 1603-1616

Question 13

incubation period of Legionnaires’ disease

Answer 13

typically 2 to
10 days.

APIC page 1621 (BOOK 2 PAGE 262)

Question 14

incubation period of Lyme disease is caused by a co iled spirochete, B. burgdorferi

Answer 14

incubation

period of several days to weeks,

Question 15

Measles in days

Answer 15

Typically,
measles has an onset of symptoms 8 to 12 days after exposure (fever, cough, coryza, and
conjunctivitis are the initial manifestations-prodrome to rash).2The rash usually appears on
average 14 days after exposure. The period of contagion begins 1 to 2 days before the onset
of overt symptoms (respiratory symptoms, not rash) and continues until 4 days after
development of the rash. The duration of viral excretion (transmissibility) is prolonged for at
least the duration of illness in immunocompromised individuals.

Question 16

The average incubation period for mumps

Answer 16

The average incubation period for mumps is 18 days, with a range of 12 to 25 days

Question 17

Mention the possible hosts of Mumps

Answer 17

Humans are the only known natural host of mumps virus

Question 18

Mumps in days

Answer 18

The period of communicability begins 1 to 2 days (but can be up to 7 days) before
onset of symptoms (e .g., parotid swelling) through 9 days thereafter.50Risk of transmission to a
susceptible person is highest over the 7-day period beginning 2 days before parotitis. Those
with re latively few or no symptoms can transmit the disease, and 30 to 40 percent of infections
are subclinical. The incubation period ranges from 12 to 25 days (usually 16 to 18 days).
Infectivity is greatest just before parotid swelling .

Question 19

Steps involved in control of outbreaks of mumps in healthcare settings include:

Answer 19

1. Definition of target population
2. Identification of susceptible persons needing vaccination
3. Exclusion of susceptible HCP who are exempt from vaccination (e.g., medical or religious
   reasons) from the affected institution or setting until the outbreak is terminated
4. Active surveillance for mumps until two incubation periods (i.e., 5 to 6 weeks) have elapsed
   since onset of the last case

Question 20

Rubella

Answer 20

81Efficient
transmission to susceptible persons requires prolonged and intimate contact. Individuals
infected with rubella are contagious from a few days before the onset of symptoms (7 days
before rash) to 7 to 14 days after the rash. Children with congenital rubella shed virus from
both respiratory secretions and urine. Children with congenital rubella should be considered to
be contagious until 1 year or more of age, unless they have had repeated negative virus
cultures of the nasopharynx and urine.

Question 21

incubation period of Rubella

Answer 21

incubation period of 14 days (range 12 to 23 days),

Question 22

HUMAN PARVOVIRUS 819

Answer 22

The incubation period is usually 4 to 14 days after exposure. However, the infection may
present up to 20 days later. The viremic phase occurs approximately 6 days after infection and
usually persists for up to a week

Question 23

The incubation period of HUMAN PARVOVIRUS 819

Answer 23

INCUBATION PERIOD
The incubation period for PVB19 varies depending on the clinical manifestation of the disease.
A range of 4 to 14 days is most common, but it may be as long as 21 days. With natural
infections, such as those that occur in households, the incubation period extends from 13 to
18 days. Two to 3 weeks after infection, rash and joint symptoms may develop.

Question 24

Diphtheria Pertusis,Chicken pox: incubation period

Answer 24

Diphtheria :1-7 days
Pertusis: 7-14 days
Chicken pox: 14-21 days

DPC instead of DPT