Staphylococcal infections

Staphylococcal infections are widespread anthropozoonotic bacterial infectious diseases with multiple mechanisms of pathogen transmission. They are characterized by the development of purulent inflammation in the affected areas, intoxication and frequent generalization of the pathological process with the development of sepsis.

Diagnosis of staph infection is based on Gram staining and culture. Treatment of staph infection is with protected beta-lactams, but because resistance to the latter is common, vancomycin may be required. Some strains are resistant to all antibiotics. Exceptions to these include newer ribosome-targeted antibiotics (eg, linezolid, quinupristin plus dalfopristin) or lipopeptide antibiotics.

ICD-10 codes

• A05.0. Staphylococcal food poisoning.
• A41.0. Septicemia due to Staphylococcus aureus.
• A41.1 Septicemia due to other specified staphylococci.
• A41.2. Septicemia due to unspecified staphylococcus.
• A48.3. Toxic shock syndrome.

What causes staph infection?

An infection is an infection of the body with microbes that can cause various diseases. In our case, we are talking about a staphylococcal infection, which has its own characteristics.

Staphylococcus is a representative of opportunistic microflora. This means that this bacterium is a constant companion of a person, living on his skin, mucous membranes and even inside the body. Under normal conditions, when the body's defenses are at their best, staphylococcus cannot cause significant harm. Even if it gets into the body, where there are all the right conditions for reproduction, the bacterium cannot cause disease if the immune system produces a sufficient amount of substances capable of maintaining opportunistic microflora in an inactive state.

Under normal conditions, staphylococcus lives in the air and on the surface of the body. How can it get inside the body? With dirty hands, with insufficiently disinfected instruments (medical surgical instruments, catheters, intravenous systems, piercing and manicure devices, shaving accessories and many others), with unwashed food products, through saliva, etc. All routes of infection (airborne, household and food) are equally relevant due to the high prevalence of staphylococcus in the environment.

Quite often, staphylococcal infection is observed in medical institutions. The reason is non-compliance with sanitary and hygienic requirements. Even when the skin is cleaned with an alcohol solution before an injection or a puncture for the purpose of taking blood, this is done not so much because of dirt and dust, but because of bacteria such as staphylococcus, which are present on the body almost constantly. This means that the risk of infection with this opportunistic bacterium is always there if the skin is not cleaned enough.

It is not necessary to think that the activation of bacteria occurs only when it enters the body through the blood or digestive tract. With weakened immunity, staphylococcal infection is dangerous even on the surface of the skin. It is enough to slightly damage the skin, and the bacteria will perceive this as a signal to act. So it is often staphylococcus that causes purulent-inflammatory processes on the skin.

Staphylococcus aureus itself (a microscopic round microorganism) is relatively harmless, even if it gets inside the body. Harm to the human body is caused by toxic products of its vital activity, which disrupt metabolic processes in cells, as a result of which local immunity decreases, and inflammatory processes develop where there is a large accumulation of bacteria, i.e. where they are actively multiplying.

Staphylococcal infection can spread throughout the body with the bloodstream, which leads to the appearance of multiple foci of inflammation and severe intoxication of the body. It is clear that leaving the disease untreated is life-threatening, but treating the disease without destroying its pathogen is impossible. Antibiotics are considered the most effective drugs against bacterial infection, and only by using them against staphylococcus can the spread of the disease be stopped.

What are the symptoms of a staph infection?

Staphylococcal infection can manifest itself in various places of our body: on the skin, in the throat, nose, ears or eyes, on internal organs. It is clear that the symptoms of the disease with different localization of the affected area will differ. The type and strain of the pathogen, the patient's age, and his immune status will play a major role in the development of the clinical picture of the pathology.

With a skin infection, various rashes with purulent contents inside can be observed. When staphylococcus enters the body through the mouth, inflammatory pathologies of the tonsils, throat and oral mucosa, as well as diseases of the respiratory system (bronchitis, pneumonia, pleurisy, etc.) or digestion (inflammatory bowel disease) can develop. Staphylococci in the nose will cause rhinitis, sinusitis and other pathologies of the nasal passages and paranasal sinuses, which can be complicated by inflammation of the middle and inner ear. But having entered the external auditory canal, staphylococcus can cause purulent-inflammatory damage to the skin of the organ of hearing. The spread of staphylococcus to the brain causes inflammation of the meninges, to the heart area - cardiac, simultaneously affecting small blood vessels.

It can be said that there is no place in the body where staphylococcus could not leave its mark when the immune system fails. And wherever bacteria begin to actively multiply, an inflammatory or purulent-inflammatory focus is formed, and the body is exposed to intoxication by the products of bacterial activity. It is clear that as the infection spreads throughout the body, the symptoms of intoxication become increasingly stronger, which causes an increase in body temperature (fever), nausea and vomiting, headaches, severe weakness and fatigue.

How is a staph infection diagnosed?

Diagnosis of staphylococcal infection is based on Gram staining and culture of infected material. Determination of antibiotic sensitivity is necessary. This is due to the fact that methicillin-resistant staphylococci are common today, and their detection requires alternative therapy.

Staphylococcal food poisoning should be suspected when cases occur in clusters (e.g., multiple family members, social groups, or restaurant customers). Confirmation of staphylococcal origin (usually done by the health department) requires isolation of staphylococci from the suspected food and sometimes enterotoxin testing.

Bone changes caused by osteomyelitis are not visible on X-ray for 10-14 days, and bone loss and periosteal reaction are not visible for even longer. Bone changes can be detected earlier by MRI, CT, and radionuclide scanners.

How is staph infection treated?

Despite the fact that staph infection is constantly present on our body and even inside the body, there is no point in treating it before the symptoms of the disease appear. A healthy, strong body is able to cope with microbes on its own. Help from the outside is needed only if the immune system is weakened, which allows bacteria to multiply freely, causing damage to various human organs and tissues.

When symptoms of the disease appear, a person consults a therapist who, if an infection is suspected, should prescribe not only the usual clinical blood and urine tests, but also offer the patient to take a test for the pathogen. This is a very important point, on which the effectiveness of the prescribed treatment largely depends.

We already know that evolution has affected not only humans or animals, but also microorganisms. Over the long years of bacteria existence, many new species and strains have emerged that react differently to antimicrobial agents. Some strains of staphylococcal infection have learned to synthesize substances that destroy the active components of antibiotics during the evolution process, which significantly reduces the sensitivity of staphylococcus to antibiotics.

The ability of bacteria to reduce the effectiveness of antimicrobial agents is called antibiotic resistance. Scientists are trying to solve this problem by creating new antibiotics with different properties. But this does not mean that over time, staphylococcus will not develop "immunity" to them. Moreover, it is very, very difficult to prevent the widespread use of antibiotics without a doctor's prescription, which contributes to the spread of the problem of antibiotic resistance.

People don't want to understand that what doesn't kill bacteria makes them stronger. The wrong drug or dosage will likely not kill the microorganism, but rather cause it to mutate, which will result in it acquiring new properties that make it resistant to antibiotics.

Well, the dosage is clear. But what does it mean that the drug is not suitable, since all antibiotics are designed to destroy bacterial infections? The thing is that infection is a general concept, since there are several types of staphylococci. And an antibiotic that would cope equally well with any type of infection has not yet been invented.

If you carefully read the information about the pharmacological properties of the drug in the instructions, you can see a list of bacteria against which this antibiotic is especially effective. Microorganisms that are partially sensitive to the drug and those that cannot be destroyed by this medicine are separately identified.

When prescribing antibiotics for staphylococcus, it is necessary to take into account the sensitivity of the identified strain to the prescribed drug. If a person has a sore throat caused by Staphylococcus aureus, there is no point in writing him a prescription for an antibiotic that is inactive or completely inactive against this type of infection.

Very often, for staph infections, broad-spectrum antibiotics are prescribed, because in addition to staph, other types of pathogenic bacteria may be in the body. And besides, such drugs can be used to begin treatment without waiting for the results of the analysis of the pathogen, which is very important in acute conditions.

Preference is usually given to beta-lactam antibiotics of the penicillin and cephalosporin series. We are used to treating almost all infectious diseases with them. But bacteria have already learned to fight them over the several years of these antibiotics' existence, so the effectiveness of these drugs is increasingly being questioned.

Some drugs are enhanced by adding beta-lactamase inhibitors (beta-lactamase is an enzyme produced by bacteria to reduce the effectiveness of beta-lactams from the penicillin and cephalosporin series), but even this does not make them omnipotent. After all, new strains of staphylococcus appear every day, which need to be regularly tested for sensitivity to antibiotics.

How is staph infection prevented?

The purpose of preventive measures is to prevent the occurrence of staphylococcal infection in everyday life, at work; staphylococcal food poisoning, hospital-acquired staphylococcal infection. To sanitize carriers and increase immunity to staphylococcal infection, pregnant women and patients subject to planned surgical intervention are immunized with purified adsorbed staphylococcal a-anatoxin.

Aseptic precautions (eg, thorough hand washing between patient examinations and sterilization of equipment) can help reduce the spread of staph in hospital settings. Strict isolation of procedures performed on patients with resistant organisms. Isolation of procedures in these patients should be continued until the infection has resolved. An asymptomatic nasal carrier does not require isolation unless the carrier is MRSA or is suspected of spreading the infection. Drugs such as cloxacillin, dicloxacillin, trimethoprim-sulfamethoxazole, ciprofloxacin (each often combined with rifampin), and topical mupirocin are effective in treating MRSA carriers, but 50% of cases of MRSA carriers rebound and become resistant to the drugs used to eliminate the organism.

Prevention of staph food poisoning involves proper food preparation. Patients with staph skin infections should not be allowed to prepare food. Food should be consumed immediately after preparation or refrigerated. Cooked food should not be stored at room temperature.