Bacterial infections in 40-day-old infants can be seen in respiratory diseases, gastrointestinal diseases and other conditions, the treatment needs to be decided according to the cause of the disease, such as acute bronchitis needs to be actively anti-infectious, while physical cooling and other treatments. 1. Respiratory diseases: acute bronchitis caused by bacterial (e.g. Streptococcus pneumoniae, etc.) infections, clinical fever, cough symptoms. Treatment requires the use of antibacterial drugs (such as cefaclor) and other anti-infective treatment, for the fever symptoms of the age of the baby, there is no safe antipyretic drugs, can be used as appropriate antipyretic patches and other physical cooling. 2. Digestive tract diseases: such as bacterial (such as Escherichia coli) infections caused by diarrhea, clinical symptoms such as diarrhea, stool culture can be seen causative organisms, the treatment of antibacterial drugs such as cefixime and other antibacterial drugs actively anti-infective treatment, at the same time, can be used in montelukast and other symptomatic treatment. 3. Urological diseases: such as urinary tract infections caused by Escherichia coli, clinical symptoms of fever, urine examination can be seen leukocytes, the same need for active anti-infection treatment, such as the use of cefaclor, cefotaxime and other drugs. 4. Other: such as intracranial infections: can be caused by bacterial infections such as meningococcus, clinical fever, convulsions and other symptoms, lumbar puncture examination can assist in the diagnosis. Treatment requires active use of antibacterial drugs such as ceftazidime and other anti-infective treatment, and the use of mannitol symptomatic supportive therapy, as appropriate. All of the above drugs should be used under the guidance of a physician, and it is recommended to consult a specialist physician for treatment.