I. Diagnosis
(A) Susceptibility factors
1.Mother’s medical history: history of infection during pregnancy and delivery (such as urinary tract infection, chorioamnionitis, etc.), colonization of the mother’s birth canal with specific bacteria, such as group B hemolytic streptococcus (GBS), gonococcus, etc.
2, obstetric factors: premature rupture of membranes, prolonged labor, cloudy or smelly amniotic fluid, unclean delivery environment or poor disinfection during delivery, prenatal and perinatal invasive examinations, etc.
3, fetal or neonatal factors: multiple births, intrauterine distress, prematurity, small for gestational age, long-term intubation, tracheal intubation, surgical procedures, bad behavior of newborns such as picking “horse teeth”, squeezing breasts, squeezing carbuncles, etc. Neonatal skin infections such as impetigo, diaper dermatitis and umbilical and pulmonary infections are also common causes.
(B) Pathogenic bacteria: Staphylococcus and Escherichia coli are predominant in China, coagulase-negative staphylococcus (CNS) is mainly seen in premature infants, especially those with long-term arteriovenous placement; Staphylococcus aureus is mainly seen in septic skin infections; prenatal or perinatal infections with Escherichia coli as the main gram-negative (G-) bacteria are more common. G- bacteria such as Pseudomonas aeruginosa, Klebsiella pneumoniae and Serratia marcescens are more common in children with tracheal intubation and mechanical ventilation.
(C) Clinical manifestations.
1.Systemic manifestations
(1)Temperature change:There may be fever or hypothermia.
(2) Less food, less crying, less movement, poor facial color, cold extremities, no weight gain or slow growth.
(3) Jaundice: Sometimes it is the only manifestation of sepsis, and in severe cases it may develop into bilirubin encephalopathy.
(4) Shock manifestations: cold extremities with florid spots, weakened femoral artery pulsation, prolonged capillary filling time, reduced blood pressure, and diffuse intravascular coagulation (DIC) in severe cases.
2.The system performance
(1) Skin and mucous membrane: sclerosis, subcutaneous gangrene, impetigo, periumbilical or other areas of cellulitis, nail bed infection, skin burns, petechiae, petechiae, oral mucosa with picking injury.
(2) Digestive system: anorexia, abdominal distension, vomiting, diarrhea, and in severe cases, toxic intestinal paralysis or necrotizing small intestine colitis (NEC), and in later stages, hepatosplenomegaly.
(3) Respiratory system: shortness of breath, cyanosis, irregular breathing or apnea.
(4) Central nervous system: easily combined with septic meningitis. The manifestations are drowsiness, agitation, convulsions, increased fontanelle tone and limb muscle tone.
(5) Cardiovascular system: infective endocarditis, infective shock. Hematologic system: may be combined with thrombocytopenia, bleeding tendency.
(6)Urinary system infection. Others:purulent inflammation of bone and joint, osteomyelitis and deep abscesses, etc.
(D) Laboratory tests.
1.Bacteriological examination
(1) Bacterial culture: try to do blood culture under strict disinfection before the application of antibiotics, suspected of intestinal origin infection should be done at the same time for anaerobic bacteria culture, there is a longer time with penicillin and cephalosporin antibiotics should do L-type bacterial culture. If prenatal infection is suspected, take gastric fluid and external ear secretions for culture within 1h after birth, or smear Gram stain to find polymorphonuclear cells and intracellular bacteria. If necessary, clean urine culture should be obtained. Cerebrospinal fluid, infected umbilical, plasma cavity fluid and all removed catheter heads should be sent for culture.
(2) Pathogenic bacteria antigen and DNA detection: use known antibodies to measure unknown antigens in body fluids, for GBS and E. coli K1 antigen can be used convective immunoelectrophoresis, latex agglutination test and enzyme chain immunosorbent assay (ELISA) and other methods, for those who have used antibiotics more diagnostic value; using the 16SrRNA gene polymerase chain reaction (PCR) typing, DNA probes, etc. Molecular biology techniques are used to assist in early diagnosis.
2.Non-specific tests
(1) White blood cell (WBC) count: blood collected after 12 h of birth is more reliable, WBC decrease (<5×109>25×109/L; >3d WBC>20×109/L).
(2) Leukocyte classification: rod-shaped nuclear cells/neutrophils (immature/totalneutrophils, I/T) ≥ 0.16.
(3) C-reactive protein (CRP): the more commonly carried out in the emergency phase protein and more sensitive items, inflammation can rise after 6-8h, ≥ 8μg/ml (peripheral blood method). Serum pre-calcitonin (PCT) or interleukin 6 (IL 6) can be measured in units where available.
(4) Platelets ≤100×109/L.
(5) Microhemoglobin ≥ 15 mm/1h.
(E) Diagnostic criteria.
1. Determine the diagnosis:with clinical manifestations and in accordance with any of the following
(1) Blood culture or sterile body cavity culture of pathogenic bacteria;
(2) If the blood culture specimen cultured conditionally pathogenic bacteria, it must be cultured with another (part) of blood, or sterile body lumen, or catheter tip of the same bacteria.
2, clinical diagnosis: with clinical manifestations and have any of the following 1) non-specific examination ≥ 2. (2) Positive blood specimen pathogenic bacterial antigen or DNA test.
II. Treatment.
(A) antibacterial drug application
1, general principles
(1) clinical diagnosis of sepsis, in the use of antibiotics before the collection of various specimens, without waiting for the results of bacteriological examination, that is, antibiotics should be used in a timely manner.
(2) according to the pathogenic bacteria may be the source of the initial determination of the pathogenic species, the pathogenic bacteria are not clear before you can choose both for gram-positive (G+) bacteria and gram-negative (G-) bacteria antibiotics, can first use two antibiotics, but should grasp different areas, different periods have different advantages pathogenic bacteria and resistance spectrum, empirical selection of antibiotics.
(3) Once the drug sensitivity results, should be adjusted accordingly, try to choose a targeted antibiotics; such as clinical efficacy, although the drug sensitivity results are not sensitive, but also temporarily do not change the drug.
(4) Generally use intravenous injection, the course of treatment 10 ~ 14d. combined with GBS and G-bacteria caused by septic meningitis (referred to as chemobrain), the course of treatment 14 ~ 21d.
2.Antibiotics mainly for G+ bacteria
(1) Penicillin and penicillins: If the infection is streptococcus (including GBS, Streptococcus pneumoniae, group D streptococcus such as Streptococcus faecalis, etc.), penicillin G is preferred; for staphylococcus including Staphylococcus aureus and CNS, penicillin is generally resistant, enzyme-resistant penicillin such as benzocillin and cloxacillin (o-chloroprim) should be used.
(2) The first and second generation cephalosporins: cefazolin is the better variety of the first generation cephalosporins, mainly for G+ bacteria, and partly for G- bacteria, but it is not easy to enter the cerebrospinal fluid; cefradine is good for G+ and G-cocci, but weak for G- bacilli. Cefuroxime is commonly used in the second generation, which is slightly weaker to G+ bacteria than the first generation, but more stable to G- and β-lactamase, so it is more effective to G- bacteria.
(3) Vancomycin: as a second-line anti-G+ antibiotic, mainly against methicillin-resistant staphylococcus (MRS).
3, mainly for G- bacteria antibiotics
(1) third-generation cephalosporins: the advantage of the lowest inhibitory concentration of enterobacteria, very easy to enter the cerebrospinal fluid, commonly used in G-bacteria caused by sepsis and chemocephalus, but should not be empirical single use of this class of antibiotics, because of the weak role of Staphylococcus aureus, Listeria monocytogenes, enterococci completely resistant. Commonly used: cefotaxime, cefoperazone (not easy to enter the cerebrospinal fluid), ceftazidime (commonly used in Pseudomonas aeruginosa septicaemia complicating the chemoencephalitis), ceftriaxone (can be the first choice of antibiotics for chemoencephalitis, but caution when neonatal jaundice).
(2) piperacillin: sensitive to G-bacteria and GBS, easy to enter the cerebrospinal fluid.
(3) Ampicillin: Although it is a broad-spectrum penicillin, the resistance rate to Escherichia coli is too high, so it is recommended to use other antibiotics for this bacteria.
(4) aminoglycosides: mainly for G-bacteria, the sterilization effect of staphylococci is also good, but into the cerebrospinal fluid is poor. Amikacin is prone to ototoxicity and nephrotoxicity in newborns, so it can be used with caution and not as the first choice if there is a basis for drug sensitivity testing and conditions for monitoring its blood concentration, and pay attention to clinical monitoring. Nethimycin has less otorhinolysis and nephrotoxicity.
(5) Aminotrans: monocyclic β-lactam antibiotics, strong effect on G-bacteria, β-lactamase stability, less adverse reactions.
4, for anaerobic bacteria: with metronidazole.
5.Other broad-spectrum antibiotics
(1) imipenem + cistatin: a new type of β-lactam antibiotics (carbapenems), the majority of G+ and G- aerobic and anaerobic bacteria have a strong bactericidal effect on the production of ultra-broad-spectrum β-lactamase bacteria have strong antibacterial activity, often as the second and third line of antibiotics. However, it is not easy to pass the blood-brain barrier and has the side effect of causing convulsions, so it is not recommended for septic meningitis.
(2) Panipenem + betametholone: another new carbapenem antibiotic, the same antibacterial spectrum as imipenem + cistatin.
(3) Ciprofloxacin: as the third generation of quinolone drugs, the effect on G-bacteria than the third generation of cephalosporin and aminoglycoside antibiotics, MRS, mycoplasma, anaerobic bacteria have antibacterial activity, is as the first choice of similar drugs. When other drugs are ineffective and have the basis of drug sensitivity, this drug can be used.
(4) Cefepime: it is the fourth generation cephalosporin, with a wide antibacterial spectrum, sensitive to G+ and G-, stable to β-lactamase, and not easy to occur drug-resistant mutations, but not sensitive to MRS.
(B) remove the foci of infection umbilical infection. Local disinfection with 3% hydrogen peroxide, 2% iodine and 75% alcohol, 2-3 times a day, and antibacterial ointment on the infected skin. The oral mucosa can also be washed with 3% hydrogen peroxide or 0.1% to 0.3% raffinate, twice daily.
(C) maintain the stability of the internal and external environment of the body. For example, pay attention to warmth, oxygen supply, correct acid-base imbalance, maintain nutrition, electrolyte balance and blood circulation stability, etc.
(D) Increase immune function and other therapies. Premature babies and those with severe infection can be treated with IVIG 200-600 mg/kg once a day for 3-5 days. Severe infections can also be treated with blood exchange therapy.