maternal, prenatal, and perinatal infections

Which maternal antibodies cross the placenta and give passive immunity to the fetus? And why these ones specifically?

IgG - it's a small, Jimmer compared to other antibodies and it's stable to survive the journeyed through placental tissue

During which gestational age does the fetus become immunologically competent?

14th week

List 4 types of maternal, diseases that can the mother can develop?

1. UTI

2. Amnionitis

3. Endometritis

4. Wound infection

Which complication of infection in pregnancy can arise? (4)

1. Spontaneous abortion

2. Perinatal death

3. Abnormal growth

4. Fetal anomalies like chorioretinitis, hydrocephaly/ microcephaly, cerebral calcifications

Which virus is commonly responsible for microcephaly?

Zika virus

What are the modes of transmission? (6)

1. Transplacental (bloodstream > placenta> baby)

2. Iatrogenic (assited instruments / amniocentesis)

3. Ascending (vaginal colonisation)

4. Perinatal (infections in the birth canal as baby comes out)

5. Breast milk (usually contracted from mother when in the wards)

6. Nosocomial (hospital acquired infections)

How does a transplacental infection spread?

Infection spread haemotogenously via the placenta

What does a transplacental infection follow?

Acute / reactivation of maternal infection

What type of microbes can be spread transplacentally? (3)

1. Blood borne viruses (HIV, Hep)

2. Bacteria

3. Parasites (malaria)

What are the consequences of fetal infection via transplacental infection?(3)

1. Preterm labour

2. Growth restriction

3. Developmental delays

Where does ascending infections come from?

Vaginal flora that are polymicrobial & with low pathogenicity (Lactobacilli makes up 90-95%, procured lactic acid)

Which microbes commonly invade the vaginal flora? (6)

1. Enterococci

2. Staphylococci

3. Streptococci

4. Coliforms (gut microbes)

5. Ureaplasma (urinary & genital tract - normal)

6. Mycoplasma (urinary& genital tract & respiratory tract - STI)

Define perinatal infection

Infection acquired around the time of delivery through contact with infective lesions / blood from colonisation or infection in the birth canal

What are some risk factors for neonatal infections? (8)

1. Difficult pregnancy

2. Prematurity

3. Prolonged rupture of membranes

4. Traumatic births

5. Post-partum infections related to poor hygiene

6. Intensive care environment

7. Indwelling devices like central venous lines / catheters)

8. Broad spectrum antibiotics (infested fungal infections)

Define asymptomatic bacteriuria

The isolation of bacteria in an appropriately collected urine sample from a person without any signs and symptoms of UTI

Why is screening and treatment of bacteriuria in pregnancy important? (2)

1. Risk of progression to severe UTI

2. Possible harm to the fetus

What percentage of women are carriers of Group B Streptococci?

25%

What percentage of babies born will be colonised? (from rectovaginal area)

50%

What percentage of babies will have Group B strep infection?

1-2 %

Early infection of Group B Streptococci leads to which condition and during which days?

Pneumonia > days 0-6

Late infection of Group B Streptococci leads to which condition and during which days?

Meningitis > days 6- 89~92 days (3 months)

How do you get a specimen to test for Group B Streptococci? When should this be done?

Take 1 sterile swap and insert it 2cm into the vaginal and then use the same swab and insert it 1 cm into the anus.

At 35-37 weeks

Which virulence factors that assist the GBS travel from the vagina into the uterus? (5)

1. Polysaccharide capsule > blocks phagocytosis

2. C5a peptide > inactivates C5a complement neutrophil chemoattractant

3. Surface pili > promotes attachment

4. CAMP factor > enhances lytic activity

5. Hyaluronate lyase > break down hosts hyaluronic acid to promote tissue spread

Which specimens can be taken for Group B Streptococci? (3)

Blood

CSF

Urine

What is the gram stain results for Group B Streptococci ?

Gram positive cocci in chains

What is the gram stain results for Group B Streptococci ?

Gram positive cocci in chains

What is the treatment for the mother with Group B Streptococci?

Penicillin / Ampicillin (IV if she stays in the wards) every 4 hours until delivery then for 21 days (start when mother is in labour)

Which risk-factors should penicillin be given to? (5)

1. Previously delivered infant with GSB

2. GBS bacteriuria during pregnancy

3. Delivery less than 37 weeks gestation

4. Duration of rupture of membrane longer than 18 hours

5. Intrapartum temperature < 38C

What is the future of maternal immunisation against GBS infection?

Vaccines that target the capsular polysaccharide of the organism + pili based vaccines

Which organism is found in many food contaminated like milk, cheese, raw, vegetables & meat?

Listeria monocytogenes

What is the route of transmission for Listeria monocytogenes? (2)

1. Ingestion of contaminated foods

2. Vertical

What is the clinical manifestation of Listeria monocytogenes? (3)

1. Bacteraemia

2. CNS infection

3. Neonatal infection

What are the early and late onset conditions of Listeria monocytogenes in neonates?

1. Early onset: Granulomatosis infantisepticum

2. Late onset: Bacterial meningitis

What is the treatment of Listeria monocyotgenes? (2)

Ampicillin + Aminoglycoside (gentamicin)

What is the general prevention for Listeria monocytogenes?

Always wash raw vegetables & thoroughly cook vegetables and meat

What is the prevention of Listeria monocytogenes in pregnancy and immunocompromised?(2)

Avoid soft cheeses

Left over / ready to eat food like hot dogs should be throughly heated prior to consumption

What is the causative agent of gonorrhoea?

Neisseria gonorrhoeae

What can gonorrhoea cause? (80% asymptomatic) (5)

1. Premature rupture of membrane

2. Preterm labour

3. Chorioamnionitis

4. Endometritis

5. Gonococcal ophthalmia neonatorum (40%)

Which treatment do you give to the mother to prevent neonatal infection?

Ceftriaxone

What are the prophylaxis in neonates with potential gonorrhoeal infections? (2)

1. Erythromycin ophthalmic ointment (0.5%) to both eyes within an hour of birth

2. Chloramphenicol

What is a complication of untreated gonorrhoea in the neonate?

Corneal ulcers leading to blindness

What is a clinical sign of opthalmia neonatorum?

Thick, purulent discharge in the eyes

Which specimen do you use to treat N. gonorrhoeae?

Eye swab

How do you diagnose N. gonorrhoeae? (3)

1. Gram negative cocci on microscopy

2. Culture on selective media

3. Or PCR of swab for chylamydia trachomatis(CT) and neisseria gonorrhoeae (NG) combined lab testing

What is the treatment of N. gonorrhoea in neonates?

Ceftriaxone 25-50 mg/ kg IV x 1 dose

What can chlamydia cause? (6)

1. Preterm labour

2. PROM

3. Chorioamnionitis

4. Endometritis

5. Conjunctivitis (18-50%)

6. Pneumonia (18%)

What is chlamydia treated with ?

Azithromycin

How do we diagnose chlamydia?

PCR

Clinical sign of chlamydia?

Thinner, less purulent discharge

What is the causative agent of syphilis?

Treponema pallidum

When does syphilis begin to infect a baby transplacentally? And the second time?

From 15th week

At birth

What are the screening tests for syphilis?

1. VDRL (Venereal Disease Research Lab test)

2. RPR (Rapid plasma reagin)

Is a mother tests positive for syphilis during the screening what are the diagnostic tests to confirm ? (2)

1. TPI

2. FTA-Abs

How do we treat syphilis?

High dose penicillin

What is the early / late syphilis time cut off?

Early is less than 2 years

Late is more than 2 years

What are the early manifestations of syphilis? (8)

1. Osteochondritis

2. Snuffles

3. Rash > on palms and soles also

4. Anaemia

5. Jaundice

6. Neurological signs

7. Lymphadenopathy

8. Mucous patches

What is a clinical manifestation of a severe form congenital syphilis?

Desquamation of hands and feet

What are the clinical late manifestations of syphilis? (8)

1. Frontal bossing

2. Short maxillas & protruding mandibles

3. Saddle nose

4. Interstitial keratitis

5. 8th nerve deafness

6. Mulberry molars, Hutchinson’s incisors

7. Saber shins

8. Flaring scapulas

When should testing of syphilis be done? (2)

Early in pregnancy and preferably again at delivery

What tests should we do in the infant to confirm status of syphilis? (2)

Venous VDRL / RPR for all infests of infected women

What is the treatment for syphilis?

Penicillin IV 10-21 days for suspected cases

What is the preventative medication for syphilis in infected mothers?

Benzathine penicillin IM once weekly for 3 weeks (in each buttocks)

What is the causative agent of toxoplasmosis?

Toxoplasma Gondii (Protozoa)

What does toxoplasmosis cause? (3)

1. Chorioretinitis

2. Encephalitis

3. Neonatal Jaundice

What diagnostic tool is used to confirm toxoplasmosis? (2)

Serology or PCR

What is the treatment for toxoplasmosis? (2)

Sulfonamides & Pyrimethamine

What are the manifestations of congenital toxoplasmosis? (4)

1. Hydrocephalus

2. Chorioretinits

3. Cirrhosis of the liver / hepatomegaly

4. Enlargement of the spleen

What are the preventative measures to avoid congenital toxoplasmosis? (4)

1. Avoid contact car feces (cleaning sandbox)

2. Wash hands with soap + water after outdoor activities

3. Wash utensils that touch raw meat throughly with soap and hot water

4. Cook all meats throughly

What is a GIT emergency in preterm infants, with surgery often indicated and baby with a very low birth weight are at the most risk?

Necrotising enterocolitis

What are the gastrointestinal presentations of necrotising enterocolitis? (7)

1. Feeding intolerance

2. Abdominal distention

3. Abdominal tenderness

4. Emesis

5. Gross blood in stool

6. Abdominal mass

7. Erythema of abdominal wall

What are the systemic presentations of necrotising enterocolitis? (7)

1. Lethargy

2. Apnea / respiratory distress

3. Temperature instability

4. Hypotension

5. Acidosis

6. Glucose instability

7. Positive blood cultures

What is the treatment for necrotising enterocolitis? If suspected / proven perforation?

1. Stop enteral feeds

2. Nasogastric decompression > low intermittent suction

3. Antibiotics > Ampicillin/ gentamicin or vancomycin/ cefotoxime

• Clindamycin