Common Infections in Children

Respiratory Tract Infections

In pneumonia cases, viruses are most commonly found as causative agents in younger children, and Streptococcus pneumoniae is the most common bacterial cause of pneumonia in childhood across all age groups 1
A significant proportion (8-40%) of community-acquired pneumonia cases in children represent mixed viral-bacterial infections 1
In older children with pneumonia, when a bacterial cause is found, it is most commonly S. pneumoniae followed by Mycoplasma pneumoniae and Chlamydia pneumoniae 1

Urinary tract infections (UTIs) are an important cause of fever in young children, with a prevalence of approximately 3-7% in children aged 2 months to 2 years with no identifiable source for fever 2, 3
UTI prevalence rates vary by age and gender, with girls younger than 1 year having a prevalence of 6.5%, and uncircumcised male infants having higher rates of UTIs compared to circumcised males 2, 3
Children with higher fevers (≥39°C/102.2°F) may have a higher prevalence of UTI 2, 3

Infants and toddlers (0-2 years) have higher rates of viral infections, especially respiratory syncytial virus, and uncircumcised male infants have higher rates of UTIs compared to circumcised males 1, 2, 3
School-aged children and adolescents have more common bacterial infections, with M. pneumoniae and C. pneumoniae infections increasing in prevalence, and S. pneumoniae remaining the most common bacterial cause of pneumonia 1

Children with delayed neurodevelopment are at higher risk for aspiration-related lung infections, often involving anaerobic organisms and Streptococcus milleri 4, 5
Foreign body aspiration can lead to lung infections, typically involving anaerobes and Streptococcus milleri 4, 5
In developing countries, the bacterial profile differs with S. aureus being the predominant pathogen in respiratory infections, especially during hot and humid months 4, 5

Staphylococcus aureus is a significant pathogen in infants, particularly in the first 6 months of life, and can still occur at 9 months, especially in developing countries, according to the American Thoracic Society 6, 7
Haemophilus influenzae type b is now rare in appropriately immunized infants, as stated by the American College of Emergency Physicians 8

The American Academy of Pediatrics recommends amoxicillin as first-line therapy for previously healthy, appropriately immunized infants with mild to moderate community-acquired pneumonia, as it provides appropriate coverage for S. pneumoniae, with a strength of evidence level of I, according to the Infectious Diseases Society of America 9
For hospitalized patients or those with severe disease, broader coverage may be warranted pending culture results, as suggested by the Infectious Diseases Society of America, with a moderate level of evidence 9