Late-onset meningitis in sick, very-low-birth-weight infants. Clinical and sonographic observations

Short information: Bacterial meningitis in very low birthweight infants in Korea from 2013-2016

BACKGROUND

Neonatal bacterial meningitis (BM) has an incidence of 0.2-0.4 per 1,000 births and a mortality rate of 20-25%. Data from the Korean Neonatal Network (KNN) were evaluated to study the incidence, mortality, and risk factors associated with BM in very-low-birthweight (VLBW; <1,500 g) infants.

METHODS

We analyzed KNN data from 2013-2016 collected from 70 neonatal units.

RESULTS

The incidence of BM in VLBW infants was 40 out of 8,263 (0.5%). The 40 infants with BM had a mean gestational age of 27.1 ± 2.0 weeks and a mean birthweight of 1,036.8 ± 220.0 g. Mean age at diagnosis was 51.5 ± 38.3 days (range, 1-171). Infants with BM were divided into two groups: Group 1 (onset age ≤ 28 days) and Group 2 (onset age > 28 days). Coagulase-negative Staphylococcus (CONS) was the most common pathogen underlying meningitis in 11 of 40 cases (28%). BM co-occurred with bacteremia in 14 of 40) of cases (35%); bacteremia was significantly more common in Group 1 than Group 2 (P < 0.05). Seizure and intraventricular hemorrhage (≥grade 3) were significantly more prevalent in Group 2 than Group 1 (P < 0.05). The mortality rate of infants with BM was 4 out of 40 (10%), which was significantly lower than that of VLBW infants without BM (1,152/8,223, [14%]; P < 0.05).

CONCLUSIONS

The incidence of BM in VLBW infants was high, but the mortality rate was low. CONS was the most common pathogen of BM in VLBW infants.

Infecciones neonatales (II)☆

Las infecciones neonatales son un problema de salud pública mundial. Su incidencia se aproxima al 1 % de los nacimientos en los países industrializados, pero es más elevada en los países en desarrollo. En 1996, las infecciones aparecidas en el primer mes de vida eran responsables de cinco millones de fallecimientos anuales.

Casi todos los microorganismos patógenos (bacterias, hongos y virus) pueden ser causantes de infecciones en el recién nacido. La epidemiología bacteriana varía según las épocas, los países e incluso las regiones, lo que impide extrapolar las propuestas terapéuticas formuladas a partir de la expenencia de un centro, tanto en lo que se refiere a los protocolos curativos como a los preventivos.

Perinatal infections and brain injury: current treatment options

Antimicrobial therapy can ameliorate infection and prevent long-term morbidity caused by several pathogens that infect the fetus and neonate. Ultimately, however, preventive strategies need to be developed and incorporated into routine preconceptional care. The future of prevention lies in immunizations, and if past and current successes with smallpox, polio, rubella, and measles vaccination programs are any indication, the future is bright for the developing fetus.

Meningitis in the Neonate

Group B beta-hemolytic streptococci and Escherichia coli strains account for approximately two thirds of all cases of neonatal meningitis, while bacteria that typically account for meningitis in older age groups (Haemophilus influenzae type B, Neisseria meningitidis, and Streptococcus pneumoniae) are infrequent causes of meningitis in the neonatal population. As with other medical problems in neonates, signs and symptoms of bacterial infection of the central nervous system are generally few in number and nonspecific in nature. Manifestations that can suggest meningitis, as well as other serious illnesses, include temperature instability, lethargy, respiratory distress, poor feeding, vomiting, and diarrhea. Signs suggestive of meningeal irritation, including stiff neck, bulging fontanelle, convulsions, and opisthotonus, occur only in a minority of neonates with bacterial meningitis and cannot be relied on solely to identify such patients. Ampicillin and either gentamicin or cefotaxime are recommended for initial empiric therapy of neonatal meningitis. When the results of the cerebrospinal fluid (CSF) culture and susceptibilities are known, therapy can be narrowed to cover the specific pathogen identified. In general, penicillin G or ampicillin is preferred for group B streptococcal meningitis, ampicillin for Listeria monocytogenes meningitis, and ampicillin plus either an aminoglycoside or cefotaxime for gram-negative meningitis. For the very low birth weight neonate who has been in the nursery for a prolonged period of time, organisms such as enterococci and gentamicin-resistant gram-negative enteric bacilli must also be considered. In patients with long-term vascular catheters, Staphylococcus aureus or coagulase-negative staphylococci must also be considered. Empiric combinations of antibiotics for such patients would include ampicillin or vancomycin, plus amikacin or cefotaxime. All neonates should undergo repeat CSF examination and culture at 48 to 72 hours after initiation of therapy. If organisms are observed on gram stain, modification of the therapeutic regimen should be considered, and neuroimaging should be performed. In general, therapy should be continued for 14 to 21 days for neonatal meningitis caused by group B streptococci or L. monocytogenes, and for at least 21 days for disease caused by gram-negative enteric bacilli. All patients with neonatal meningitis should have hearing and development monitored serially. The first audiologic evaluation should occur 4 to 6 weeks after resolution of the meningitis.

Clinical outcomes of neonatal meningitis in very-low birth-weight infants

We sought to describe the clinical presentation and consequences of meningitis among 64 very-low-birth-weight (VLBW <1.5 kg) infants who had 67 culture-proven episodes of meningitis over an 18-year period, 1977 through 1995. Demographic and neonatal descriptors of meningitis and later outcomes were retrospectively examined and neurodevelopmental outcomes of 39 of 45 (87%) meningitis survivors were compared to those of nonmeningitis survivors followed up to 20 months corrected age. Causes of meningitis included coagulase-negative Staphylococcus in 43% of episodes, other gram-positive bacteria in 19%, gram-negative bacteria in 17%, and Candida species in 20% of episodes. Spinal fluid abnormalities were sparse, regardless of etiologic organism. Of 38 nonbloody spinal fluid taps (<1,000 erythrocytes/mm3), 6 had >30 leukocytes/mm3, 5 protein >150 mg/dL%, and 6 glucose <30 mg/dL (1.67 mmol/L). Only 10 infants (26%) had 1 or more of these spinal fluid abnormalities. Meningitis survivors had a higher rate of major neurologic abnormality (41% vs 11%, p<0.001) and subnormal (<70) Mental Development Index (38% vs 14%, p<0.001) than nonmeningitis survivors. Impairment rates did not differ by etiologic organism. The effect of meningitis on neurologic outcome persisted even after controlling for birth weight, intraventricular hemorrhage, chronic lung disease, and social risk factors (odds ratio 2.27 [95% CI 1.02, 5.05]). We conclude that despite a sparsity of abnormal spinal fluid findings, culture-proven neonatal meningitis among VLBW infants has a detrimental effect on neurologic outcome, which persists even after controlling for other risk factors.