bacterial infection (S-Y)

Question 1

how are Salmonella serotypes be categorized?

Answer 1

-typhoidal (typhoid & paratyphoid fever) - Typhi, Paratyphi A, tartrate negative Paratyphi B, Paratyphi C

-nontyphoidal (acute diarrhea)

Question 2

how are the Salmonella (nontyphoidal) transmitted?

Answer 2

animal reservoirs (domestic and wild)
- eating contaminated foods (dairy, eggs, meat, raw produce)
- drinking contaminated water
- contact with people who have a diarrheal illness

Question 3

what increases the risk of nontyphoidal salmonella infection after exposure?

Answer 3

taking AB or antacid medication

Question 4

what are the symptoms of nontyphoidal salmonella infection?

Answer 4

acute diarrhea (incubation 12-96 hours, but it can be more than 7 days)
abdominal cramps, fever, usually resolves without treatment after 1-7 days

Question 5

what % of people develop bacteremia or focal invasive infection (osteomyelitis, meningitis, endovascular infection, septic arthritis) from nontyphoidal salmonella infection?

Answer 5

5% (higher among infants, older adults, immunocompromised)

ppl with atherosclerosis, hemoglobinopathies, or maligantn neoplasms - increased risk for extraintestinal infection

Question 6

how to diagnose nontyph salmonella infection?

Answer 6

culture (routine stool culture, abscesses, blood, CSF, urine)

Question 7

how to treat salmonellosis?

Answer 7

• most just supportive care - rehydration therapy
• AB not recommended for most with uncomplicated salmonellosis (does not shorten the duration of illness and can prolong bacterial shedding)

Question 8

who should get AB treatment for salmonellosis?

Answer 8

Consider antibiotic therapy for patients with suspected invasive disease (e.g., patients with severe diarrhea, high fever, manifestations of extraintestinal infection) and for patients at increased risk for invasive disease (e.g., infants, older adults, people who are immunocompromised, patients with known atherosclerosis). For these populations, treat infections empirically until susceptibility results are available.

Question 9

which empiric AB drug should be used for salmonellosis?

Answer 9

fluoroquinolones in adult travelers (resistance rising globally)
ceftriaxone - children and adults with invasive disease (resistance rare)
azithromycin can be used for children and is an alternative agent for adults

Question 10

what causes tetanus?

Answer 10

Clostridium tetani - spore-forming, anaerobic, gram positive

Question 11

tetanus is more common in which area?

Answer 11

in rural and agricultural regions; areas where contact with soil or animal excreta is likely; warm and moist environments; and areas where immunization against tetanus is inadequate.

Question 12

which countries have not achieved maternal and neonatal tetanus elimination?

Answer 12

Afghanistan, Angola, Central African Republic, Guinea, Mali, Nigeria, Pakistan, Papua New Guinea, Somalia, Sudan, South Sudan, Yemen

Question 13

what is average incubation period for tetanus?

Answer 13

• incuation on average 10 days (3-21 days)
• duration of the incubatino period is inversely related to the severity of symptoms –> shorter incuation = riskier

Question 14

how do you classify tetanus symptoms?

Answer 14

generalized, localized, and cephalic

generalized: >80%, lockjaw, generalized spasms, risus sardonicus, opisthotonus

localized: muscle spasms confined to the injury site

cephalic: head or face wound and flaccid cranial nerve palsies

Question 15

how does neonatal tetanus occur?

Answer 15

contaminated umbilical stumps and whose mothers are unimmunized or inadequately immunized

long term sequelae - behavioral, intellectual, and neurologic abnormalities

Question 16

what is case-fatality ratios for generalized tetanus? localized tetanus?

Answer 16

25~100%
<1%

Question 17

how to dianose tetanus?

Answer 17

clinical findings with epidemiologic support only

Question 18

how to treat tetanus?

Answer 18

• tetanus immune globulin (TIG)
• aggressive wound care and debridement
• supportive care
• AB 7-10 days: metronidazole; alternative is IV penicillin G
• must be hospitalized in a quiet, dim room to minimize spasms

Question 19

Under 7 years, which tetanus vaccine is available? how many doses for children?

Answer 19

DTaP (diphtheria-tetanus-acellular pertussis)
DT (diphtheria-tetanus)
Infants/children - 5 doses of DTaP at 2, 4, 6, 15-18 months, 4-6 years

Question 20

from 10 years old, which tetanus vaccine is avaialbe?

Answer 20

-Tdap (tetanus-diphtheria-acellular pertussis)
-adolescent shoudl receive 1 dose of Tdap at 11-12 years of age
-Children 7 and up can receive Tdap for catch-up vaccination

Question 21

for pregnancy what is the indication of tetanus vaccination?

Answer 21

27-36 weeks’ gestation
unvaccinated pregnant people should receive 2 doses of TTCV during their pregnancy

Question 22

what is contraindication & precaution of tetanus vaccination?

Answer 22

• encephalopathy without an identifiable cause occurring within 7 days of a previous dose of DTP, DTaP or Tdap - for the pertussis component of the vaccines; can receive either DT or Td
• progressive or neurolgic disorder due to pertussis component

Question 23

when do you get tetanus vaccination for wound management?

when do you get tetanus TIG for wound management?

Answer 23

TTCV: history of tetnus vaccine unknown or less than 3 previous doses

TIG: history of tetanus vaccine unknown or less than 3 previous doses and the wound is not clean/minor wound.

Question 24

what is the causing agent of tuberculosis?

Answer 24

Mycobacterium tuberculosis complex - rod-shaped, nonmotile, slow-growing, acid-fast bacteria including M. bovis and M. tuberculosis hominis

Question 25

how is the TB transmited?

Answer 25

- coughs, through the air - unpasteurized dairy products from infected cattle (bovine TB - caused by M. bovis)

Question 26

what is multidrug-resistant TB resistant to?

Answer 26

at least the 2 most effective drugs - isoniazid and rifampin

Question 27

how to diagnose TB?

Answer 27

8-10 weeks after exposure, do tuberculin skin test (TST) or interferon-gamma release assay (IGRA)

Question 28

how much % of people who are infected with TB progress to TB disease? If not progress to TB disease, what happens?

Answer 28

5-10% -if not progress, it remains inactive (latent TB infection) -- no symptoms, cannot spread the infection to others

Question 29

how long does it take TB to progress to TB?

Answer 29

weeks to decades after initial infection

Question 30

what are the symptoms of TB?

Answer 30

70-80% cases are lung related; others bladder, bones and joints, brain and meninges, genitalia, kidneys, lymph nodes, pleura prolonged cough, fever, hemoptysis, night sweats, decreased appetite, weight loss

Question 31

when do you do pretravel and posttravel testing for TB?

Answer 31

- who anticipate possible prolonged exposure to TB - care for patients, work in health care facilities, prisons or jails, refugee camps, homeless shelters; - who plan to stay in TB-endemic countries

Question 32

which 3 methods are used for TB testing?

Answer 32

1. culture methods - takes 2 weeks, can identify M. tuberculosis complex species 2. microscopy - sputum smear or other body tissues or fluids - can see AFB (acid-fast bacilli) but cannot distinguish M. tuberculosis from nontuberculous mycobacteria 3. Nucleic Acid Amplification Tests - less sensitive than culture but more sensitive than AFB smear; specific for M. tuberculosis complex - rapidly confirm diagnosis and help guide initial treatment until culture results return.

Question 33

how to treat latent TB?

Answer 33

- 3 months once weekly isoniazid and rifapentine - 4 months rifampin daily - 3 months isoniazid and rifampin daily - 6-9 months isoniazid daily

Question 34

what are the interactions of rifampin with other meds?

Answer 34

interaction with oral contraceptives and certain antiretrovral medications

Question 35

how to treat TB?

Answer 35

- isoniazid, rifampin, ethambutol and pyrazinamide for 2 months, then isoniazid and rifampin for additional 4 months

Question 36

how to treat drug-resistant TB?

Answer 36

- older tx: 4-6 drugs for 18-24 months - new tx: bedaquiline, pretomanid, linezolid (all oral) for 6 months

Question 37

how to prevent TB?

Answer 37

Bacillus Calmette-Guerin (BCG) vaccine - at birth in countries with higher TB burdens - but low and variable efficacy in preventing TB in adults

Question 38

if you had BCG vaccine, which TB test is preferred?

Answer 38

IGRA - BCG might give false-positive TST results

Question 39

how to prevent infections from Mycobacterium bovis and other foodborne pathogens?

Answer 39

avoid unpasteurized diary products

Question 40

when do you do 2nd TST for travelers?

Answer 40

- if TST testing for the first time - not needed if already been tested and found to have a negative result within the previous 2 years - 2nd method - TST baseline negative --> retest 1-3 weeks after; if 2nd is negative then pt is not infected; if 2nd is positive, pt have skin test boosting, possibly because of previous M. tuberculosis infection

Question 41

what is the infectious agent of typhoid fever and paratyphoid fever (=enteric fever)?

Answer 41

Salmonella enterica serotypes Typhi, Paratyphi A, Paratyphi B, and Paratyphi C

Question 42

how do you differentiate Paratyphi B strains (2 distinct pathotypes)?

Answer 42

based on their ability to ferment tartrate 1. Paratyphi B - unable to ferment tartrate and is associated with paratyphoid fever 2. Paratyphi B var. L(+) tartrate(+) - ferments tartrate and is associated with gastroenteritis typical of nontyphoidal salmonellosis.

Question 43

other than water and food, what would be the rare route of transmission of enteric fever?

Answer 43

sexual contact, MSM

Question 43

how are enteric fever transmitted?

Answer 43

only humans - water or food by feces of person (a person can be acute, chronic, or asymptomatic carrier)

Question 44

each year, how many cases are there for typhoid fever and paratyphoid fever worldwide? how many death per year?

Answer 44

typhoid - 11-21 million cases para - 5 million cases 135,000-230,000 deaths per year

Question 45

which returning countries are most reported for enteric fever?

Answer 45

South Asia (Bangladesh, India, Pakistan), Africa, Latin America, SE Asia lower risk regions - East Asia and the Caribbean

Question 46

what is the incubation period for enteric fever?

Answer 46

6-30 days

Question 47

what are the symptoms of enteric fever?

Answer 47

gradual onset - increase fatigue and a fever that increases daily from low-grade to 38-40 degress in 3-4 days. fever lowest in AM, peaking late afternoon or evening. all experience anorexia, headache, malaise. abdominal pain, constipation, diarrhea are common. (more in children) dry cough, fatigue, myalgias, sore throat hepatospenomegaly often can be detected. a transient, maculopapular rash of rose-colored spots can occasionally be seen on the trunk. clinical presentation is often confused with malaria. untreated, case-fatality ratios are 10-30%; treated <1% serious complications of typhoid fever occur in 10-15% of hospitalized patients - GI hemorrhage, intestinal performation, encephalopathy

Question 48

how to diagnose enteric fever?

Answer 48

blood culture (bacteremia) - a single culture is positive in only 50% of cases - multiple blood cultures might be required; cultures might need to be held and observed for up to 7 days before reporting a negative result bone marrow culture - more invasive but increases the sensitivity to 80%, and is relatively unaffected by previous or concurrent AB use. stool culture - usually not positive during the first week of illness and has less diagnostic sensitivity than blood culture. rapid diagnostic tests are not very reliable.

Question 49

what are the regional estimates for multidrug-resistant (MDR) Typhi in South Asia and Africa?

Answer 49

9% 35-59%

Question 50

what is the treatment of choice for enteric fever?

Answer 50

fluoroquinolones (eg. cipro)- but resistance >90% returning from South Asia Azithromycin and ceftriaxone are increasingly being used as empiric

Question 51

patients with suspected typhoid fever who traveled to Iraq or Pakistan, or who did not travel internationally before their illness began, what is the empiric tx for uncomplicated & complicated illness?

Answer 51

uncomplicated: azithromycin complicated: carbapenem

Question 52

what is the empiric treatment of typhoid fever for travelers returning from most other countries then Iraq or Pakistan?

Answer 52

ceftriaxone

Question 53

when do you consider treatment with alternative ABs for enteric fever or begin looking for a persistent focus of infection (e.g. an abscess, or an infection in a bone, joint, or other extraintestinal site)?

Answer 53

if fever do not subside within 5 days

Question 54

how many % of relapse occurs after clinical recovery of enteric fever?

Answer 54

10%

Question 55

what is the efficacy of typhoid vaccines?

Answer 55

50-80%

Question 56

what are the new type of typhoic vaccines?

Answer 56

protein conjugated Vi vaccines (80% effective)

Question 57

what is the age indication of oral Vivotif? how often is the booster dose?

Answer 57

6 years and up every 5 years

Question 58

how to take vivotif?

Answer 58

- 1 caps every other day, with cool liquid no warmer than 37 degrees, 1 hour before a meal, 2 hours after meal - no alcohol 1 hour before and 2 hours after - complete at least 1 week before

Question 59

contraindication of vivotif (Ty21a)?

Answer 59

pregnant, or immunocompromised people

Question 60

how long do you need to wait to get oral typhoid (Ty21a) vaccine after antimicrobial agents? or vice versa?

Answer 60

72 hours

Question 61

are there any interactions between oral typhoid and other live virus vaccines?

Answer 61

no

Question 62

when should you take oral typhoid vaccine after oral cholera vaccine?

Answer 62

8 hours after

Question 63

are there any interactions between oral Ty21a and immune globulin?

Answer 63

no

Question 64

what causes yersiniosis?

Answer 64

yersinia species - facultative anaerobic gram - coccobacili Yersinia enterocolitica (serogroups O:3, O:5, 27, O:8, and O:9) Yersinia pseudotuberculosis Yersinia pestis is not included (this causes plague)

Question 65

how are Yersinia spp transmitted?

Answer 65

consuming or handling food - raw or undercooked pork ; unpasteurized milk ; drink untreated water ; direct or indirect contact with animals through the fecal-oral route.

Question 66

which animals are involved with Yersinia?

Answer 66

Pigs - major domestic (dogs), farm (cattle), wild (deer) can also transmit

Question 67

who is at greater risk for yersiniosis infection and severe disease?

Answer 67

ppl with high iron levels (e.g. hemochromatosis, thalassemia), including those on iron chelation treatment

Question 68

which countries have cases reported for yersiniosis?

Answer 68

norther Europe - Scandinavia; Canada, Japan

Question 69

what are the symptoms of yersiniosis?

Answer 69

incubation 4-6 days - gradual symptoms; enterocolitis is the most common symptoms (abdominal pain, diarrhea- can be bloody and persist for several weeks), fever sore throat can occur, particularly in children. Mesenteric adenitis (pain mimicking appendicitis). Necrotizing enterocolitis in young infants. reactive arthritis affecting the wrists, knees, and ankles can occur, usually 1 month after the initial diarrhea episode, resolving after 1-6 months. erythema nodosum, manifesting as painful, raised red or purple lesions along the trunk and legs, can occur, and usually resolves spontaneously within 1 month.

Question 70

how to diagnose Yersoniosis?

Answer 70

isolate the organism from bile, blood, CSF, mesenteric lymph nodes, peritoneal fluid, stool, a throat swab, or wounds. Culture-independent diagnostic tests (CIDTs) now available. culture needed for antimicrobial susceptibility testing.

Question 71

how to treat yersiniosis?

Answer 71

self-limited moderate to severe - AB; aminoglycosides, third-generation cephalosporins, fluoroquinolones, tetracyclines, trimethoprim-sulfamethoxazole - typically resistant to 1st gen cephalo and most penicillins.