Nosocomial infections

A “nosocomial infection” (nosocomial infection) , as defined by the World Health Organization, is any clinically expressed disease of microbial origin that infects a patient as a result of hospitalization or visiting a medical institution for the purpose of treatment, as well as hospital personnel due to his activities, regardless of whether or not the symptoms of this disease appear while these people are in the hospital.

A synonym for this concept is nosocomial infection, that is, acquired by a patient in a medical institution. The term “hospitalism” is closely associated with this concept — the stubborn, prolonged existence in hospitals of highly virulent strains of multiresistant microorganisms called hospital or resident strains, often leading to outbreaks of nosocomial infections.

Despite the tremendous achievements in the field of diagnostic and treatment technologies, the problem of nosocomial infections remains one of the most urgent in modern conditions, is gaining increasing medical and social significance, as they complicate the course of the underlying disease, extend the duration of treatment by 1.5–2, and more than once, they contribute to the chronization of the process and a high level of disability.

According to domestic and foreign researchers, nosocomial infections develop in 5-20% of hospitalized patients. Mortality in various nosological forms of nosocomial infections ranges from 35 to 60%, and in the case of generalization of infection reaches the same level as in the pre-antibiotic period.

The structure of nosocomial infections in hospitals is specific and is determined by the capacity of the beds, the profile and nature of the hospital

treatment, as well as nosology and age composition of patients. There are more than 200 types of microorganisms that cause hospital infections. Table 10 presents the main classes of these microorganisms.

In multidisciplinary hospitals, purulent-septic infections (GSI) predominate, they make up 65-75% of the total number of nosocomial infections. Intestinal infections occupy the second place (7-10%), among which salmonellosis prevails. In third place (3-5%) is a group of infections with predominantly parenteral transmission of the pathogen (hepatitis B, C, D, F, G, TTV; cytomegalovirus and HIV infection). In addition, a group of airborne infections (measles, measles, rubella, mumps, diphtheria, scarlet fever, chicken pox, tuberculosis, influenza, etc.) is distinguished; their specific weight is 5–8% of all nosocomial infections. A group of rare infections (legionellosis, pneumocystosis, Crimean hemorrhagic fever, etc., including especially dangerous infections) takes 1-2%.

GSI as the dominant group of nosocomial infections is most often registered in patients with a surgical profile, especially in the emergency and abdominal surgery, traumatology and urology departments.

In the hospital environment, there are 2 groups of GSI pathogens:

• obligate microorganisms that cause diseases as a result of a decrease in the body’s defenses;

• facultative microorganisms living and accumulating in the hospital environment, acquiring resistance to antibiotics and disinfectants and in the form of hospital strains causing the development of the epidemic process.

Pathogens for Hospital Infections

A pathogen strain is considered to be hospitalized, which has adapted to the specific conditions of the hospital, acquired resistance to adverse factors in the hospital environment, and caused at least two cases of clinically pronounced hospital infection.

The sources of nosocomial infections are patients and bacteriocarriers from among the patients and health care staff, among which the most dangerous are medical personnel belonging to the group of long-term carriers and patients with erased forms of the disease, as well as long-term patients in the hospital who often become carriers of stable nosocomial strains. The role of visitors to hospitals as sources of nosocomial infections is recognized by most researchers as extremely insignificant.

by the group 4, the contact-instrumental pathway is designated as the artifactal , that is, artificially created in the process of diagnosis and treatment, transmission pathway of nosocomial infections. Clinical classification of nosocomial infections suggest their separation:

• by type of pathogen (caused by obligate pathogenic and conditionally pathogenic microorganisms);                                  

• by the duration of the course (acute, subacute, chronic);                                  

• in severity (mild, moderate, severe clinical course);                                  

• by the degree of infection prevalence (generalized , localized). Contagious instruments, respiratory and other medical equipment, linen, bedding, mattresses, beds, patient care items, dressings and sutures, endoprostheses, drains, transplants can be factors of transmission of a pathogen from a source of infection to a susceptible organism, surfaces of “wet” objects (taps, sinks, etc.), contaminated solutions of antiseptics, antibiotics, disinfectants, aerosol and other drugs, blood, blood substituting and blood substituting other liquids, overalls, shoes, hair, hands of patients and staff, water, food. In a hospital environment, so-called secondary epidemiologically dangerous reservoirs of pathogens in which microflora survive for a long time and even multiply. 

Depending on the pathways or mechanisms of transmission, nosocomial infections are classified as follows:

Airborne droplets; Water-alimentary; Contact household; Contact instrumental:

a) post-injection b) postoperative c) postpartum d) post-transfusion e) postendoscopic e) post-transplantation g) postdialysis

h) posthemosorption. Post-traumatic. Other.

The first three groups of transmission methods of nosocomial infections are called naturally occurring. Such reservoirs are most often liquids, solutions or moisture-containing objects – the above infusion solutions, drinking solutions, distilled water, hand creams, water in flower vases, air conditioner humidifiers, showers, drains and water locks sewers, hand washing brushes and even solutions of disinfectants with a low concentration of active agent.

For example, the stick of blue-green pus (Pseudomonas aeruginosa) has a huge potential for survival and growth: it remains on the hands for several hours, multiplies in physiological saline, weak solutions of disinfectants, in wet rags, and “freezes” in dry crystalline phenol.

local_offerevent_note August 22, 2019

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