Neonatal Bacterial Infections In Developing Countries

CHAPTER 1

BRIEF OVERVIEW OF NEONATES

A neonate (from Latin, neonates) is a baby that is 28 days old or younger and also known as a newborn. This term includes premature, mature and postmature infants. The neonatal period is the first 28 days of the child’s life and this is when changes are very rapid. The child is at the highest risk of dying during this first 4 weeks of life and it is therefore important that appropriate care and feeding are provided to the child at this period, both the increase the child’s chance at survival and the prevent foundations of an unhealthy life for the infant.

A lot of crucial events take place during this period:

• Feeding patterns are established
• Parents and infant bonding begins
• Risks of infection in infants are higher
• Birth defects or congenital defects are first noted

Immediately after birth during the first hours of life, newborns should receive vitamin K, eye care, and recommended immunizations( birth dose of OPV and Hepatitis B).

The infants should be evaluated for birth defects, gestational weight, birth weights, congenital defects, and any signor symptom of newborn sickness. Sick newborns, preterm infants ,low birth weight infants and infants exposed or infected by HIV or congenital syphilis are provided with special care.

APGAR SCORING

Apgar score helps to identify breathing problems and other health issues. This is part of the special attention given to a baby in the first few minutes after birth; the baby is checked for muscle tones, heart and respiratory rates, reflexes and colour at 1 minute and 5 minutes after birth.

A baby who has issues with any of these is given constant attention during those 5-10 minutes and the Apgar score is given after this issues have been resolved.

Each area can have a score of 0, 1, or 2, with 10 points as the maximum. Most babies score 8 or 9, with 1 or 2 points taken off for blue hands and feet because of immature circulation. If a baby has a difficult time during delivery and needs extra help after birth, this will be shown in a lower Apgar score. Apgar scores of 6 or less usually mean a baby needed immediate attention and care.

Sign Score = 0 Score = 1 Score = 2

• Heart rate Absent Below 100 per minute Above 100 per minute
• Breathing effort Absent Weak, irregular, or gasping Good, crying
• Muscle tone Flaccid Some flexing of arms and legs Well-flexed, or active movements of arms and legs
• Reflex or irritability No response Grimace or weak cry Good cry
• ColorBlue all over, or pale Body pink, hands and feet blue Pink all over

BIRTH WEIGHT

A baby’s weight is a very important marker of health. Full term babies are born between 37-41 weeks of pregnancy and their average weight is 7 pounds(3.2kg). very small or very large babies are at higher risk for problems.babies are weighed daily in the nursery to check for growth and the babys need for fluid and nutrition. Newborn babies may often lose 5% to 7% of their birth weight. This means that a baby weighing 7 pounds 3 ounces at birth might lose as much as 8 ounces in the first few days. Babies will usually gain this weight back within the first 2 weeks after birth. Premature and sick babies may not begin to gain weight right away.

MEASUREMENTS

The measurements taken my hospitals staff include:

1. Head circumference: The distance around the baby’s head.
2. Abdominal circumference: The distance around the baby’s abdomen.
3. Length: Measurement from the top of the head to the heel.
4. Temperature: This checks that the baby is able to have a stable body temperature in normal room.
5. Pulse: The newborn’s pulse is normally 120 to 160 beats per minute.
6. Breathing rate: The newborn’s breathing rate is normally 40 to 60 breaths per minute.

PHYSICAL EXAM

A complete physical exam is an important part of newborn care. The healthcare provider carefully checks each body system for health and normal function. The provider also looks for any signs of illness or birth defects. Physical exam of a newborn often includes:

1. General appearance: This looks at physical activity, muscle tone, posture, and level of consciousness.
2. Skin: This looks at skin colour, texture, nails, and any rashes.
3. Head and neck: This looks at the shape of head, the soft spots on the baby’s skull, and the bones across the upper chest (clavicles).
4. Face: This looks at the eyes, ears, nose, and cheeks.
5. Mouth: This looks at the roof of the mouth (palate), tongue, and throat.
6. Lungs: This looks at the sounds the baby makes when he or she breathes. This also looks at the breathing pattern.
7. Heart sounds and pulses in the groin (femoral)
8. Abdomen: This looks for any masses or hernias.
9. Genitals and anus: This checks that the baby has open passages for urine and stool.
10. Arms and legs: This checks the baby’s movement and development.

GESTATIONAL ASSESSMENT

The healthcare provider will check how mature the baby is. This is an important part of care. This check helps figure out the best care for the baby if the dates of a pregnancy are uncertain. For example, a very small baby may actually be more mature than he or she appears by size, and may need different care than a premature baby needs.

Dubowitz/Ballard Examination is used by health providers to know gestational age. This exam can closely estimate a baby’s gestational age, it’s also looks at a baby’s skin and other physical features, plus the baby’s movement and reflexes. The physical maturity part of the exam is done in the first 2 hours of birth. The movement and reflexes part of the exam is done within 24 hours after birth. The health provider often uses the information from this exam to help with other maturity estimates.

PHYSICAL MATURITY

The physical maturity part of the Dubowitz/Ballard exam looks at physical features that look different at different stages of a baby’s gestational age. Babies who are physically mature usually have higher scores than premature babies.

Points are given for each area of assessment. A low of -1 or -2 means that the baby is very immature. A score of 4 or 5 means that the baby is very mature (postmature). The areas focused on are:

1. Skin textures: The skin is checked to see if its sticky, smooth, or peeling
2. Soft, downy hair on the baby’s body (lanugo): This hair is not found on immature babies. It shows up on a mature infant, but goes away for a postmature infant.
3. Plantar creases: These are creases on the soles of the feet. They can be absent or range up to covering the entire foot.
4. Breast: The provider looks at the thickness and size of breast tissue and the darker ring around each nipple (areola).
5. Eyes and ears: The provider checks to see if the eyes are fused or open. He or she also checks the amount of cartilage and stiffness of the ears.
6. Genitals (male): The provider checks for the testes and how the scrotum looks. It may be smooth or wrinkled.
7. Genitals (female): The provider checks the size of the clitoris and the labia and how they look.

MATURITY OF NERVES AND MUSCLES

The health care provider performs 6 checks on the baby’s nerves and muscles.

A score is given to each area looked at. Normally, the more mature the baby is, the higher the score. The areas checked are:

1. Posture: This looks at how the baby holds his or her arms and legs.
2. Square window: This looks at how far the baby’s hands can be flexed toward the wrist.
3. Arm recoil: This looks at how much the baby’s arms “spring back” to a flexed position.
4. Popliteal angle: This looks at how far the baby’s knees extend.
5. Scarf sign: This looks at how far the baby’s elbows can be moved across the baby’s chest.
6. Heel to ear: This looks at how near the baby’s feet can be moved to the ears.

After which the physical assessment score and the nerves and muscles score are added together, the healthcare provider can then estimate the baby’s gestational age. Scores range from very low for immature babies to very high scores for mature and postmature babies.

NEONATAL BACTERIAL INFECTIONS

The normal fetus is sterile until very shortly before birth as long as the amniotic membrane remains intact. After birth, the neonate rapidly acquires commensal bacteria that colonise the skin and mucous membranes.

The host defence mechanisms are not well developed at this stage and some commensals may become opportunist pathogens, particularly in compromised neonates who must remain in hospital for the treatment of congenital abnormalities. The gastrointestinal tract is colonised soon after birth, mainly by facultative bacteria.

Studies have shown that anaerobes colonise the neonatal gastrointestinal tract during the first week of life and are greater in number and variety than aerobes or facultative species. Subsequently, only micro-organisms that can adapt to live in this mixed population of facultative and anaerobic species will colonise the various parts of the tract and become part of the resident flora.

NEONATAL INFECTION

Infections in neonates are caused by bacteria and some by viruses. A mother’s birth canal contains bacteria, especially if they have an active infection. The baby can swallow or breathe in fluid in the birth canal during childbirth and bacteria and viruses can enter their lungs and blood. This can cause the baby to become sick either during childbirth or within the first few days after birth. As the bacteria or viruses multiply, the newborn baby becomes ill very quickly. The sooner the infection is discovered and treated, the better the outcomes will be for the newborn baby.

Infections are a major cause of neonatal mortality and are responsible for approximately one third of the total neonatal deaths worldwide. Early recognition of illness in sick neonates, appropriate care and prompt access to appropriate treatment is needed to reduce the neonatal mortality.

There are several bacteria and viruses that can be transmitted from mother to newborn baby during pregnancy or childbirth.

These are ways in which neonatal infection can be acquired:

1. In utero transplacentally or through ruptured membranes
2. In the birth canal during delivery (intrapartum)
3. From external sources after birth (postpartum)

Common viral agents include herpes simplex viruses, HIV, Cytomegalovirus(CMV), and hepatitis B. Intrapartum infection with HIV or hepatitis B occurs from passage through an infected birth canal or by ascending infection if delivery is delayed after rupture of membranes; these viruses can less commonly be transmitted transplacentally. CMV is commonly transmitted transplacentally.

Bacterial agents include group B streptococci, enteric gram-negative organisms (primarily Escherichia coli), Listeria monocytogenes, gonococci, and chlamydiae.

IN UTERO INFECTION

In utero infection can occur any time before birth and it results from overt or subclinical maternal infection. Consequences depend on the agent and timing of infection in gestation and include spontaneous abortion, intrauterine growth restriction, premature birth, stillbirth, congenital malformation (eg, rubella), and symptomatic (e.g., cytomegalovirus [CMV], toxoplasmosis, syphilis) or asymptomatic (e.g., CMV) neonatal infection.

Common infectious agents transmitted transplacentally include rubella, toxoplasma, CMV, and syphilis. HIV and hepatitis B are less commonly transmitted transplacentally.

INTRAPARTUM INFECTION

Neonatal infections with herpes simplex viruses, HIV, hepatitis B, group B streptococci, enteric gram-negative organisms (primarily Escherichia coli), Listeria monocytogenes, gonococci, and chlamydiae usually occur from passage through an infected birth canal during childbirth. Sometimes ascending infection can occur if delivery is delayed after rupture of membranes.

POSTPARTUM INFECTION

Postpartum infections are acquired from direct contact with an infected mother (e.g., TB, which also is sometimes transmitted in utero) or through breastfeeding (e.g., HIV, CMV) or from contact with family or visitors, health care practitioners, or the hospital environment.

SYMPTOMS OF INFECTION

Determining if a new born has an infection may be difficult because healthy newborn babies can also have some of these symptoms even though there is no infection. The symptoms of a beginning infection are listed below.

• irregular temperature below 36.6 degrees C or above 38.0 degrees C, taken rectally
• poor feeding and difficulty waking to feed
• excessive sleepiness
• irritability
• rapid breathing at a rate over 60 breaths per minute
• change in behaviour
• As the infection gets worse, the newborn baby may develop additional symptoms:
• difficulty breathing
• bluish tinge around mouth
• pale or grayish skin
• high body temperature (above 38.0 degrees C, taken rectally)

low body temperature (under 36.6 degrees C, taken rectally), despite being wrapped with clothes and blankets

In a newborn baby with an infection, these symptoms will continue and the baby needs to be checked by a doctor.

DIAGNOSIS OF INFECTION

Several tests can be used to diagnose the infection in a new born. However, the test results usually take two to three days to come back, so in the interim, the doctor will prescribe antibiotics for the newborn baby while they are waiting for the test results to confirm the diagnosis. For example, rapid breathing could be caused by infection, and any delay in treatment could result in the newborn baby becoming much more ill.

The following tests may be needed to correctly diagnose infection in new born babies:

Complete blood count: A sample of baby’s blood is taken. The complete blood count (CBC) will determine the number of each type of blood cell (red blood cells, white blood cells, haemoglobin, and platelets). Special attention is focused on the number of white blood cells (WBCs), as these can be abnormal in number when an infection is present. An abnormal number of WBCs is often a marker that the newborn baby’s body is fighting some sort of infection. Results of the CBC can be obtained quite quickly.

Blood culture: The blood culture will determine if any bacteria can be grown in the blood. If bacteria grow in the culture, it means the baby has an infection in the bloodstream. The results of this test can take up to 24 hours and sometimes longer, which is why treatment is not delayed while waiting for the result.

Urine test: A sample of the newborn baby’s urine is taken to determine its white cell count and taken for culture.

Eye or skin swab: This is when pus or fluid from a possible site of infection, such as the eye or umbilical cord, is swabbed and taken for analysis.

Chest X-ray: If the baby is suspected to have pneumonia, a chest x-ray is needed.

Spinal tap: A lumbar puncture is also called a spinal tap, and it is necessary if meningitis (infection of the lining of the brain), is suspected. Before doing a lumbar puncture, a numbing cream should first be applied to the area of the spine where the lumbar puncture will take place. Local anaesthetic is then used to numb the site of the lumbar puncture. A hollow needle is inserted between the bones, called the vertebrae of the spine. A sample of the cerebrospinal fluid is withdrawn through the needle and tested for infection. This is not a comfortable procedure; however, sedation and pain relief are provided to reduce the baby’s discomfort. Meningitis is a serious infection and the diagnosis can only be confirmed by examination of the cerebrospinal fluid.