What Is a Bacterial Infection?
When the skin and mucous membranes are damaged or purulent inflammation occurs, bacteria easily invade the body;
Bacterial infections
- Bacterial infection is an acute systemic infection caused by pathogenic bacteria or conditional pathogens invading the blood circulation to produce toxins and other metabolites. It is clinically characterized by chills, high fever, rash, joint pain, and hepatosplenomegaly. Some may have septic shock and migrating lesions. Acute systemic infection caused by pathogenic microorganisms invading blood from wounds or infections in vivo. Clinically, some patients may experience irritability, cold limbs and cyanosis, thin pulse rate, faster breathing, and lower blood pressure. Especially the elderly, children, those with chronic diseases or immunocompromised, those who are not treated promptly and have complications, can develop into sepsis or sepsis.
Causes of bacterial infections
Human factors of bacterial infection
- When the skin and mucous membranes are damaged or purulent inflammation occurs, bacteria easily invade the body;
- The human immune response can be divided into two types: non-specific immune response and specific immune response. The latter can be divided into two aspects: cellular immunity and humoral immunity. When the body's immune function declines, it cannot fully play its role in swallowing and killing bacteria. Even if the amount of invading bacteria is small, the pathogenicity is not strong can cause infections; iatrogenic infections caused by conditional pathogens are gradually increasing. .
Bacterial infection
- Mainly related to the virulence and quantity of pathogenic bacteria. Pathogenic bacteria with strong virulence or a large number enter the body, which is more likely to cause sepsis. Whether bacteria cause infection after they invade the human body is related to human defense, immune function, bacterial virulence and quantity. Intact skin and mucous membranes are a natural barrier to prevent bacteria from invading the human body. After damage, bacteria easily invade the body from here, and they are more likely to invade when squeezing skin inflammation sites or abscesses. In severe burns, the wound surface opens the door for bacteria, skin necrosis and plasma exudation provide a good environment for bacteria to multiply, so infection is extremely easy to occur. After the mucous membrane of the urinary tract, biliary tract, gastrointestinal tract, and respiratory tract is damaged, if there is stagnation of content and increased pressure at the same time, bacteria will more easily enter the blood, and catheters such as catheters and veins will be retained. Intubation during artificial assisted breathing Etc., also make bacteria easy to invade. When the body's immune function is normal, the bacteria that enter the blood are quickly cleared by blood defense cells such as monocytes and neutrophils, and those with chronic diseases such as liver cirrhosis, diabetes, blood disease, connective tissue disease, etc. Due to metabolic disorders, reduced humoral immunity and cellular immune function, sepsis is prone to occur; the use of various immunosuppressive drugs and radiation therapy are also the reasons for the high incidence of sepsis. After the use of broad-spectrum antibacterial drugs, although drug-sensitive bacteria are suppressed or killed, some drug-resistant bacteria take the opportunity to reproduce, which can also cause sepsis.
Basis of bacterial infection
- Patient factors: Age: The age of onset is infants and the elderly. They have poor resistance and high incidence. Newborns are more susceptible to this disorder due to immature immune function. The smaller the birth weight, the higher the incidence.
- Bacterial infections
- Factors related to rickets: A large number of pathogenic bacteria secrete virulent endotoxins, exotoxins, enzymes and pathogenic factors, are highly invasive, and have sufficient blood circulation in the portal, which are conducive to the occurrence of sepsis. The types of pathogenic bacteria change continuously with the age of sick children and the development of drugs. In the past, the pathogenic bacteria of pediatric sepsis, in addition to the neonatal period may be E. coli, more common are streptococcus, staphylococcus and pneumococcus, followed by meningococcus and influenza bacilli; typhoid and paratyphoid, Pseudomonas aeruginosa, etc. Rare. Since the widespread clinical application of antibiotics, beta hemolytic streptococcus and pneumococcal sepsis have been significantly reduced in group A. Staphylococci are more likely to cause sepsis due to the increase in resistant strains. At present, Staphylococcus aureus and coagulase-negative Staphylococcus epidermidis are often the main pathogens of sepsis. but,
- Bacterial infections
Bacterial infection etiology
- Due to the widespread use of antibacterial and immunosuppressive drugs, the pathogenic bacteria have also changed. 1950
- staphylococcus
Clinical manifestations of bacterial infections
- Primary inflammation: The primary inflammation caused by various pathogenic bacteria is related to its distribution in the human body. Primary inflammation is characterized by local redness, swelling, heat, pain, and dysfunction.
- Toxemia symptoms: more rapid onset. There are often chills, high fever, and fever is mostly relaxation heat or intermittent heat.
- Hemolytic streptococcus
- Rash: Seen in some patients, petechiae are most common, and they are mostly distributed on the trunk, limbs, eye conjunctiva, oral mucosa, etc.
- Joint symptoms: Large joint redness, swelling, heat, pain, and limited mobility can occur, even with joint fluid and pus, which are more common in the course of sepsis such as Gram-positive cocci, meningococci, and alcaligenes.
- Septic shock: About 1/5 to 1/3 of sepsis patients, showing irritability, fine pulse, cold limbs, skin spots, decreased urine output and blood pressure, etc., and can occur DIC, is a severe poison Due to bloodemia.
- Hepatosplenomegaly: Usually only mildly enlarged.
- Except for traumatic, postoperative, and postoperative sepsis, which have obvious incubation periods, most of them have sudden onset, and patients have repeated chills, persistent high fever, general malaise, headache, rapid heart rate, shortness of breath, nausea, vomiting, etc. In severe cases, irritability, convulsions, convulsions, coma, complexion and pale or flaky skin, cyanosis of lips and nail beds, cold limbs, rapid pulse, decreased blood pressure, decreased urine output, or anuria may occur. Extensive internal organ bleeding, multiple organ failure, and other symptoms of toxemia. Some patients have large joints with redness, swelling, pain, restricted movement, joint cavity fluid or pus, hepatosplenomegaly, subcutaneous abscess, lung abscess, liver abscess, pericarditis, and bone marrow
- Bacterial infections
- Because neonatal and elderly patients have different physiological characteristics, their sepsis also has its own characteristics. The neonatal skin and mucosal barrier function, lymphatic and monocyte phagocytic system functions are not yet complete, complements are lacking, humoral immunity is low, and cellular immunity is not perfect; umbilical cord stumps create favorable conditions for bacterial invasion, and pregnant women have urogenital reproduction Infection of the tract or systemic infection can make neonatal sepsis a high incidence, complicated manifestations, and complications. Clinical manifestations are often lacking of "typical" symptoms, such as non-rise in temperature, weight gain, malaise, drowsiness, irritability, convulsions, pale complexion, blueness around the mouth, shortness of breath, fast heart rate, flowery skin, increased jaundice, breast rejection, vomiting, Abdominal distension, diarrhea, hepatosplenomegaly. The incidence of sepsis in the elderly tends to increase. Due to poor body responsiveness, early clinical manifestations are hidden, and the heat pattern is often irregular; and because of low immune function, the disease is often more severe, progress is rapid and difficult to control; organ function in the elderly Most of them are chronic or chronic diseases, and sepsis can easily induce organ failure. Therefore, neonatal and senile sepsis have a poor prognosis and a high mortality rate. The timely detection of neonatal and senile sepsis is mainly based on age characteristics and increased vigilance.
Bacterial infection check
- First, pathogen detection
- (1) Specimen collection and inspection principles
- Different materials: According to the distribution and discharge of different pathogens in the body, take different specimens. Try to take materials from obvious parts of the disease.
- Strictly aseptic operation to avoid sample contamination: aseptic material collection to prevent contamination by bacteria.
- Proper handling: Specimens should be collected before using antibacterial drugs.
- Send inspection as soon as possible: Specimens must be fresh and submitted for inspection as soon as possible after collection. Most bacteria can be transported under refrigeration. Fecal specimens should be added with glycerol buffered saline preservation solution.
- Make a mark and fill in the test list.
- (II) Examination of morphology and structure of bacteria
- Microscopy
- Bacteria are tiny and cannot be seen directly by the naked eye. Usually, the oil microscope lens of an optical microscope is used to observe the morphology of bacteria at a magnification of about 1000 times, while the internal ultrastructure of bacteria must be magnified tens of thousands of times with an electron microscope to observe.
- staining method.
- Staining with a single dye can observe the size, morphology and arrangement of bacteria, but cannot identify bacteria.
- Counter-staining method uses more than two different dyes to stain different bacteria. In addition to observing the morphological characteristics of bacteria, it can also identify bacteria. The most commonly used are
- Gram stain
- Methods After the bacterial smear was fixed by flame, it was first stained with crystal violet for 1 minute, then iodized with iodine for 1 minute, then decolorized with 95% alcohol for 30 seconds, and finally counterstained with diluted fuchsin for 30 seconds.
- Results Gram-positive bacteria were purple and Gram-negative bacteria were red.
- The principle is mainly due to the different cell wall structure of G + bacteria and G- bacteria; secondly, the isoelectric point (pI2 ~ 3) ratio of G + bacteria
- G-bacteria (pI4 ~ 5) is low, so the binding force between G + bacteria and basic dyes is stronger than G- bacteria.
- Practical significance can identify bacteria, choose the use of antibiotics, and study the pathogenicity of bacteria.
- Bacterial staining methods also include acid staining and special staining methods such as capsules, spores, flagella, cell walls, and cytoplasm.
- Isolation and identification is the most reliable way to diagnose bacterial infections.
- The main contents of the appraisal are:
- Culture characteristics specimens are inoculated into the culture medium to obtain pure culture. According to the nutrition, growth conditions, and colony characteristics required for bacteria, make preliminary identification.
- Morphological characteristics Through isolation and culture, colonies or pure cultures are microscopically examined after smear staining, and preliminary identification is made based on the morphology, arrangement, size, stainability and special structure of the bacteria.
- Pathogens with different biochemical reactions have different enzyme systems and different metabolites, which helps to identify bacteria.
- Serological identification: Use a diagnostic serum containing a known specific antibody and an isolated purebred bacterial strain to perform a slide agglutination test to determine the species or type of pathogenic bacteria. Immunofluorescence, synergistic agglutination tests, and convection immunoelectrophoresis can also be used. Rapid and sensitive methods such as radioimmunoenzyme and immunoassay, which directly detect specific antigens from specimens, can help determine the cause.
- Animal tests are mainly used to isolate, identify pathogenic bacteria, and determine the toxicity of strains. Common experimental animals include mice, guinea pigs and rabbits.
- Drug sensitivity test is of great significance to guide clinical selection of medicines and timely control of infection. Common methods are single-plate paper dish method and test tube dilution method.
- Detection of pathogenic bacteria Antigens are detected with known specific antibodies. Their advantages: fast, sensitive, high specificity. Commonly used immunological techniques are
- Precipitation reaction:
- Cooperative agglutination test:
- immunofluorescence method (IF);
- Convection immunoelectrophoresis (CIE):
- Enzyme immunoassay (EIA)
- Immunoimprinting
- Other detection methods
- Radon gas-liquid chromatography is commonly used for the detection of anaerobic bacteria.
- Genetic diagnostic methods Different types of bacteria have different genes or base sequences. The diagnostic method that detects the presence of specific gene sequences of microorganisms is called genetic diagnosis of microorganisms. Nucleic acid hybridization, PCR, and DNA fingerprinting are commonly used.
- [Nucleic acid hybridization] The pathogen nucleic acid can be detected directly from the specimen, which is especially suitable for pathogens that cannot or are difficult to isolate and culture.
- Principle: A single-stranded nucleic acid sequence with a known sequence is used as a probe. Under certain conditions, the hybridization with the unknown single-stranded nucleic acid in the processed sample is performed according to the base complementarity rule. Through autoradiography, we know whether there is a specific sequence and Know the probe binding.
- Methods: There are liquid phase and solid phase. Solid phase is more commonly used. There are in situ hybridization, dot hybridization, Southern blotting, Northern blotting, etc.
- [PCR Technology] is a cell-free molecular cloning technology that selectively amplifies DNA or RNA fragments in vitro. It is fast, highly specific and extremely sensitive.
- [DNA fingerprint] It is mainly used in epidemiological investigations and other aspects. Including bacterial chromosomal DNA and plasmid DNA fingerprints.
Bacterial infection test
- Hematology: The total number of white blood cells has increased significantly.
- Etiology check.
- Bacterial culture.
- Bacterial smear: direct smear examination of pus, cerebrospinal fluid, pleural and ascites fluid, petechiae, etc. can also detect pathogenic bacteria, which has certain reference value for the rapid diagnosis of sepsis.
- A detailed medical history and detailed medical examination are extremely important. Where acute fever, leukocytes, and neutrophils are significantly increased, and there is no tendency to be confined to a systemic infection, or there is a history of local lesions, catheters, and device operation, the possibility of sepsis should be considered; blood or bone marrow culture is positive As the basis for the diagnosis. It should be distinguished from typhoid fever, miliary tuberculosis, connective tissue disease, and lymphoma.
Treatment of bacterial infections
- General and symptomatic treatment: bed rest, strengthen nutrition, and add appropriate vitamins. Maintain water, electrolyte and acid-base balance. Transfusion, plasma, albumin, and gamma globulin are given if necessary. When the fever is high, physical cooling can be given, and sedatives can be given to those who are irritable.
- Pathogen treatment. The timely selection of appropriate antibacterial drugs is the key to treatment. Attention should be paid to early, sufficient and mainly bactericides; generally, two antibacterial drugs are used in combination and given intravenously; the first dose should be large, pay attention to the half-life of the drug, and divided into doses; the course of treatment should not be too short, generally three More than a week, or 7 to 10 days after the fever retreat can be discontinued as appropriate.
- Treatment of local lesions: Pyogenic lesions, whether primary or migratory, should be punctured or incised for drainage in a timely manner based on the use of appropriate and sufficient antibiotics. Purulent pleurisy, joint abscesses, etc. can be locally injected with antibacterial drugs after puncture drainage. Obstruction of biliary and urinary tract infections should be considered surgical treatment.
- The key is to choose appropriate antibacterial drugs in time and give them rest and proper nutrition. After the diagnosis is basically positive, treatment should be carried out as soon as possible. Before the positive result of culture is obtained, the type of pathogenic bacteria can be inferred based on the bacterial invasion pathway and clinical manifestations. Suitable for antibacterial drugs. For Gram-positive cocci infections, penicillin, erythromycin, and cephalosporins can be selected; for gram-negative bacterial infections, gentamicin, amikacin, cephalosporin, and semi-synthetic broad-spectrum penicillin can be used; For anaerobic infections, metronidazole is the first choice. Penicillin, chloramphenicol, and clindamycin can also be selected; amphotericin should be used if sepsis is indeed caused by fungi. In addition, it is also important to correctly handle local lesions and prominent contradictions at various stages (such as septic shock, diffuse intravascular coagulation, and heart and kidney dysfunction).
Prevention of bacterial infections
- Always keep the skin and mucous membranes clean and intact, avoid trauma, avoid squeezing or pricking sores with needles, and actively treat and control chronic diseases. Use immunosuppressants and antibiotics reasonably. Burn wards should be strictly disinfected. Prevention happens. If all obvious or hidden suppurative lesions can be cleared early, the incidence of infection can be reduced. Infectious diseases common in children, such as measles, influenza, whooping cough, etc., are often prone to secondary bacterial infections of the respiratory tract, which can cause bacterial infections. For such children, protection must be strengthened. No matter how small the skin trauma must be paid attention to, appropriate treatment early. With the continuous improvement of environmental hygiene, personal hygiene, nutritional status and pediatric health care, the incidence of bacterial infections will inevitably decline.
Bacteria Infection Yu-Gi-Oh Card
- Card package: DL4
- Japanese name: Bacterial infection
- Rarity: Pinka N
- Card type: Magic
- Magic Type: Equipment
- Effect: It is possible to equip monsters other than the robot family. The equipped monster's attack power drops by 300 during each of its own preparation processes.
- Used to reduce the opponent's monster attack damage