Nosocomial infections are various infectious diseases that have been infected in a medical institution. Depending on the degree of spread, generalized (bacteremia, septicemia, septicopiemia, bacterial shock) and localized forms of nosocomial infections (with lesions of the skin and subcutaneous tissue, respiratory, cardiovascular, urogenital system, bones and joints, central nervous system, etc.) are distinguished. Identification of pathogens of nosocomial infections is carried out using laboratory diagnostic methods (microscopic, microbiological, serological, molecular biological). In the treatment of nosocomial infections, antibiotics, antiseptics, immunostimulants, physiotherapy, extracorporeal hemocorrection, etc. are used.
General information
Nosocomial (hospital, nosocomial) infections are infectious diseases of various etiologies that have arisen in a patient or a medical employee in connection with a stay in a medical and preventive institution. An infection is considered to be nosocomial if it has developed no earlier than 48 hours after the patient’s admission to the hospital. The prevalence of nosocomial infections (NI) in medical institutions of various profiles is 5-12%. The largest share of nosocomial infections falls on obstetric and surgical hospitals (intensive care units, abdominal surgery, traumatology, burn injury, urology, gynecology, otolaryngology, dentistry, oncology, etc.). Nosocomial infections are a major medical and social problem, since they aggravate the course of the underlying disease, increase the duration of treatment by 1.5 times, and the number of deaths is 5 times.
Etiology and epidemiology
The main causative agents of nosocomial infections (85% of the total) are conditionally pathogenic microorganisms: gram-positive cocci (epidermal and Staphylococcus aureus, beta-hemolytic streptococcus, pneumococcus, enterococcus) and gram-negative rod-shaped bacteria (Klebsiella, Escherichia, Enterobacter, proteus, pseudomonas, etc.). In addition, in the etiology of nosocomial infections, the specific role of viral pathogens of herpes simplex, adenovirus infection, influenza, parainfluenza, cytomegaly, viral hepatitis, respiratory syncytial infection, as well as rhinoviruses, rotaviruses, enteroviruses, etc. is great. Also, nosocomial infections can be caused by conditionally pathogenic and pathogenic fungi (yeast-like, mold-like, radiant). The peculiarity of intrahospital strains of conditionally pathogenic microorganisms is their high variability, drug resistance and resistance to environmental factors (ultraviolet, disinfectants, etc.).
The sources of nosocomial infections in most cases are patients or medical personnel who are bacterial carriers or patients with erased and manifest forms of pathology. Studies show that the role of third parties (in particular, hospital visitors) in the spread of NI is small. Transmission of various forms of hospital infection is realized by means of airborne, fecal-oral, contact, transmissive mechanism. In addition, a parenteral route of transmission of nosocomial infection is possible during various invasive medical manipulations: blood collection, injections, vaccination, instrumental manipulations, operations, ventilation, hemodialysis, etc. Thus, it is possible to get infected with hepatitis B, C and D, purulent-inflammatory diseases, syphilis, HIV infection in a medical institution. There are cases of nosocomial outbreaks of legionellosis when patients receive therapeutic showers and whirlwind baths.
The factors involved in the spread of nosocomial infection can be contaminated care items and furnishings, medical instruments and equipment, solutions for infusion therapy, overalls and hands of medical staff, reusable medical devices (probes, catheters, endoscopes), drinking water, bedding, suture and dressing material, and many others.
The significance of certain types of nosocomial infection largely depends on the profile of the medical institution. Thus, Pseudomonas aeruginosa prevails in burn wards, which is mainly transmitted through care items and the hands of staff, and the main source of nosocomial infection is the patients themselves. In maternity institutions, the main problem is staphylococcal infection, spread by medical personnel carrying Staphylococcus aureus. In urological departments, infection caused by gram-negative flora dominates: intestinal, Pseudomonas aeruginosa, etc. In pediatric hospitals, the problem of the spread of childhood infections – chickenpox, mumps, rubella, measles – is of particular importance. The occurrence and spread of nosocomial infection is facilitated by violation of the sanitary and epidemiological regime of medical facilities (non-compliance with personal hygiene, asepsis and antiseptics, disinfection and sterilization regime, untimely identification and isolation of persons who are sources of infection, etc.).
The risk group most susceptible to the development of nosocomial infection includes newborns (especially premature babies) and young children; elderly and weakened patients; persons suffering from chronic diseases (diabetes mellitus, blood diseases, kidney failure), immunodeficiency, oncopathology. A person’s susceptibility to nosocomial infections increases in the presence of open wounds, cavity drains, intravascular and urinary catheters, tracheostomy and other invasive devices. The frequency of occurrence and severity of the course of nosocomial infection is affected by the patient’s long stay in the hospital, prolonged antibiotic therapy, immunosuppressive therapy.
Classification
According to the duration of the course, nosocomial infections are divided into acute, subacute and chronic; according to the severity of clinical manifestations – into mild, moderate and severe forms. Depending on the degree of prevalence of the infectious process, generalized and localized forms of nosocomial infection are distinguished. Generalized infections are represented by bacteremia, septicemia, bacterial shock. In turn, among the localized forms, there are:
- infections of the skin, mucous membranes and subcutaneous tissue, including postoperative, burn, traumatic wounds. In particular, they include omphalitis, abscesses and phlegmons, pyoderma, erysipelas, mastitis, paraproctitis, fungal infections of the skin, etc.
- infections of the oral cavity (stomatitis) and ENT organs (angina, pharyngitis, laryngitis, epiglottitis, rhinitis, sinusitis, otitis, mastoiditis)
- infections of the bronchopulmonary system (bronchitis, pneumonia, pleurisy, lung abscess, lung gangrene, pleural empyema, mediastinitis)
- infections of the digestive system (gastritis, enteritis, colitis, viral hepatitis)
- eye infections (blepharitis, conjunctivitis, keratitis)
- infections of the urogenital tract (bacteriuria, urethritis, cystitis, pyelonephritis, endometritis, adnexitis)
- infections of the musculoskeletal system (bursitis, arthritis, osteomyelitis)
- infections of the heart and blood vessels (pericarditis, myocarditis, endocarditis, thrombophlebitis).
- CNS infections (brain abscess, meningitis, myelitis, etc.).
In the structure of nosocomial infections, purulent-septic diseases account for 75-80%, intestinal infections – 8-12%, hemocontact infections – 6-7%. Other infectious diseases (rotavirus infections, diphtheria, tuberculosis, mycoses, etc.) account for about 5-6%.
Diagnosis
Criteria that allow us to think about the development of nosocomial infection are: the occurrence of clinical signs of the disease no earlier than 48 hours after admission to the hospital; connection with invasive intervention; identification of the source of infection and the transmission factor. The final judgment on the nature of the infectious process is obtained after the identification of the pathogen strain using laboratory diagnostic methods.
To exclude or confirm bacteremia, bacteriological blood culture is carried out for sterility, preferably at least 2-3 times. With localized forms of nosocomial infection, microbiological isolation of the pathogen can be made from other biological media, in connection with which urine, feces, sputum, wound discharge, material from the pharynx, smear from the conjunctiva, from the genital tract to the microflora is seeded. In addition to the cultural method of detecting pathogens of nosocomial infections, microscopy, serological reactions (ELISA), virological, molecular biological (PCR) methods are used.
Nosocomial infections treatment
The difficulties of treating nosocomial infection are due to its development in a weakened body, against the background of the underlying pathology, as well as the resistance of hospital strains to traditional pharmacotherapy. Patients with diagnosed infectious processes are subject to isolation; thorough current and final disinfection is carried out in the department. The choice of an antimicrobial drug is based on the features of the antibioticogram: with nosocomial infection caused by gram-positive flora, vancomycin is most effective; gram–negative microorganisms – carbapenems, cephalosporins of the IV generation, aminoglycosides. Additional use of specific bacteriophages, immunostimulants, interferon, leukocyte mass, vitamin therapy is possible.
If necessary, percutaneous blood irradiation, extracorporeal hemocorrection (hemosorption, lymphosorption) is performed. Symptomatic therapy is carried out taking into account the clinical form of nosocomial infection with the participation of specialists of the appropriate profile: surgeons, traumatologists, pulmonologists, urologists, gynecologists, etc.
Prevention
The main measures for the prevention of nosocomial infections are reduced to compliance with sanitary and hygienic and anti-epidemic requirements. First of all, this concerns the disinfection regime of premises and care items, the use of modern highly effective antiseptics, high-quality pre-sterilization treatment and sterilization of instruments, strict adherence to the rules of asepsis and antiseptics.
Medical personnel should observe personal protective measures during invasive procedures: wear rubber gloves, goggles and a mask; handle medical instruments carefully. Vaccination of health workers against hepatitis B, rubella, influenza, diphtheria, tetanus and other infections is of great importance in the prevention of nosocomial infections. All employees of medical institutions are subject to regular routine medical examination aimed at identifying the carrier of pathogens. To prevent the occurrence and spread of nosocomial infections, it will be possible to reduce the time of hospitalization of patients, rational antibiotic therapy, the validity of invasive diagnostic and therapeutic procedures, epidemiological control in medical institutions.