Healthcare Settings: Epicenter Of Nosocomial Infections

JK News Today

Nosocomial infections or hospital acquired infections are endogenous or exogenous infections which a patient acquires either during hospitalization or soon after discharge from the hospital. Hospitals and hospital-like settings tend to gather many sick under one roof and hence, serve as a reservoir of numerous infectious agents. These overcrowded healthcare settings with inability to maintain hygienic conditions are threat not only to the patients but also to the healthcare workers. Increasing population of immune-compromised patients including the aged-ones, unsafe medical care, surgical procedure, injections, transplants are some of the major causes of spread of nosocomial infections. Nosocomial infections have severe adverse effects. It leads to emotional stress, functional disability and even death in certain cases. Mortality caused by nosocomial infections in India is more than any other form of accidental death. It also prolongs the hospital stays and adds to the economic burden of managing the underlying disease. The active cooperation of the Healthcare workers for better implementation of the existing preventive and control measures along with the technical advances will contribute much to fight against the nosocomial infections.

The overcrowding of the healthcare settings with the patients and the inability to maintain hygienic conditions contributes much to the spread of nosocomial infections. Prevalence of such conditions has made healthcare settings an epicenter of the infectious agents. As a result, patients undergoing a treatment of any particular ailment develop a secondary infection which at times is more serious than the existing ailment. Increasing population of immuno-compromised patients including the aged-ones, aggressive medical interventions including antimicrobial treatments and surgical procedures, rising population of antimicrobial resistant strains due to selective pressures and changing environmental conditions are the major factors contributing to the spread of nosocomial infections.

If a patient either during hospitalization or after discharge from the hospital develops an endogenous or exogenous infection which was neither present nor incubating at the time of admission to the hospital. Such an infection is known as nosocomial infection (NI) or hospital acquired infection (HAI). Nosocomial infections can be caused by the endogenous microflora of one’s own body, can be acquired from contact with the hospital staff or from the other patients in the hospital. Shorter stay of the patients in the healthcare units prevents the early detection of this infection. Also, it becomes difficult to diagnose whether the infection source was endogenous or exogenous. The average postoperative stay nowadays is 5 days which is shorter than the 5-to 7-days incubation period for S. aureus surgical wound infections3. The symptoms of the infection become visible only after the patients are discharged.

FREQUENCY OF NOSOCOMIAL INFECTIONS

There has been a global increase in nosocomial infections in the healthcare settings and these infections have contributed much in increasing the morbidity and mortality rates. Also they prolong the hospital stays and add to the economic burden of managing the underlying disease. It is estimated that 5-10 per cent of all the hospitalized patients develop hospital acquired infections ,i.e., of every 100 hospitalized patients at any given time, 5-7 in developed and 10 in developing countries will acquire at least one nosocomial infections6. On the basis of monthly reports (more than 270 institutions report) of hospital acquired infections from a non-random sample of US hospitals which was received by CDC’s National nosocomial infections surveillance (NNIS) system, it was concluded that the rate of nosocomial infections increased by 36% from 7.2 in 1975 to 9.8 in 1995 due to progressively shorter inpatient stays. The estimated nosocomial rate in USA was 4.5% in 2002, corresponding to 9.3 infections per 1000 patient-days. The rate of nosocomial infections is as low as 1 per cent in developed countries like Europe and America whereas in parts of Asia, Latin America and Sub-Saharan Africa the rate of nosocomial infections is more than 40 per cent9. In India, Nosocomial infection rate is at over 25 per cent which means nosocomial infection develops in 1 patient in every 4 patients admitted to the hospital. According to a study conducted in a tertiary teaching hospital in Goa, out of 498 patients followed, 103 people developed 169 nosocomial infections. 26.63% suffered from Urinary tract infection, which was found to be the most common nosocomial infection, followed by surgical site infection (23.67%), wound infection (23%) and nosocomial pneumonia (18.34%). Nosocomial phlebitis and septicemia, respectively, accounted for 4.73% and 3.55% of the total Nosocomial Infections. Nosocomial infections are often associated with some or the other invasive support measures like central intravenous lines (CVL), urinary tract catheters and mechanical ventilators. Records have shown that ninety one percent of blood infections were in patients with central intravenous lines (CVL), ninety five percent of pneumonia cases developed in patients undergoing mechanical ventilation, and seventy seven percent of urinary tract infections were in patients with urinary tract catheters. Reintubation, genetic syndromes, immunodeficiency, and immunosuppression in paediatric patients are some of the factors that contribute to the development of ventilator-associated pneumonia (VAP). In paediatric patients, the risk factors contributing to development of nosocomial urinary tract infections include bladder catheterization, prior antibiotic therapy and cerebral palsy4. Catheter hub colonization, exit site colonization, catheter insertion after one week of life, disruption of catheter dressing and extremely low birth weight (less than 1000 g) at the time of catheter insertion increases the risk of catheter-associated bloodstream infections in new-born child.

NOSOCOMIAL INFECTIONS AS OPPORTUNISTIC INFECTION

Opportunistic infections are those infections which infect the person with weak immune system or immunocompromised patients. These are secondary infections which attack the body when its immune system is already busy fighting other chronic illness or when the immune system is compromised due to malnutrition, fatigue, HIV infection, chemotherapy, skin damage, antibiotic treatment or some immunosuppressing agents like corticoids, etc. and hence is vulnerable to attack by infectious agents. In last twenty years, the infections of opportunistic fungi have emerged as a cause of death and poor health in many patients. Earlier, majority of the opportunistic fungal mycoses was caused by Aspergillus spp. and Candida spp. But during the past decade, infections by some of the uncommon opportunistic fungal microorganisms have also been reported which includes Trichosporon (yeast), Fusarium spp. (filamentous fungi), Penicillium mameffei (endemic dimorphic fungi), zygomycetes and a variety of dematiaceous moulds.

CAUSES OF SPREAD OF NOSOCOMIAL INFECTIONS

Unsafe medical care is the prime cause of spread of nosocomial infections, specially, in underdeveloped and developing countries1. Recently, strong evidences suggesting the unsafe healthcare facilities to be an important factor in transmitting HIV have been found. The reason for the widespread of nosocomial infections are as follows:

1. Crowding of patients in a hospital or healthcare setting increase the chances of spreading an infection.
2. The risk of nosocomial infection increases with age and illness as they decrease the immune strength.
3. An invasive treatment may pave a way for the entry of the infectious agents inside the body. The increasing use of invasive devices like mechanical ventilators, urinary catheters and central intravenous lines is the key factor contributing to the spread of nosocomial infections specially if used without proper training or laboratory support.
4. Rapidly increasing antibiotic resistance among the microorganisms has increased the difficulty of healthcare workers to combat the deadly infection. Up to 60 per cent of hospital infections are caused by drug-resistant microbes and in 35 to 40 per cent of the infections the microorganism is resistant to the best drug commonly used to treat that infection. The excessive use of broad spectrum antibiotics has led to the development of antibiotic resistance among the microorganisms. Vancomycin-resistant Enterococci (VRE) and methicillin-resistant S. aureus (MRSA) are the major gram-positive nosocomial micro-organisms and P. aeruginosa, Klebsiella, and Enterobacter that harbor chromosomal or plasmid-mediated beta-lactamase enzymes are major gram-negative antimicrobial resistant pathogens of concern. The development of resistance to antibiotic acyclovir and ganciclovir in Herpes virus is major threat to immunocompromised patients, particularly HIV-infected patients. The WHO report on infectious diseases states that due to emerging co-infection with HIV, the cases of visceral leishmaniasis are increasing at an alarming rate in countries like India and Sudan and in certain parts of India, over 60 per cent of visceral leishmaniasis cases no longer respond to the first- line drug. Candida spp. with intrinsic resistance to azole antifungal agents (e.g., C. krusei) and to amphotericin B (e.g., C. lusitaniae) has emerged as grave concern in oncology units.
5. The frequent use of unnecessary injections (e.g., routine injections of vitamins like vitamin B-12 or an antibiotic such as carbapenems) should be avoided. In the developing countries more than 50 per cent of the needles, syringes or both are reused i.e. are unsafe10. As a consequence nearly 80,000 to 160,000 new HIV infections occur annually in Sub-Saharan Africa. Much more cases of HBV and HCV occur annually because of unsafe injections.
6. The emergence of new pathogenic agents have further aggravated the existing problems.

Besides the above mentioned causes of nosocomial infection spread, poor infection prevention practices, improper use of limited resources and lack of supervision are major causes of nosocomial infections in developing countries.

TYPES (OR SITES) OF NOSOCOMIAL INFECTIONS

• URINARY TRACT INFECTION: The rate of urinary tract nosocomial infection accounts for 35 per cent of all the nosocomial infections but costs the least in terms of economics, mortality and morbidity. Its occurrence is very high in the patients who have an indwelling catheter or have had a kidney transplant. A catheter is associated with nearly 80 per cent of all the hospital acquired urinary tract infections.
• SURGICAL SITE INFECTION: Surgical site infections accounts 40 per cent of all the hospital acquired infections. They prolong the hospital stay, have expensive treatment and have higher rates of morbidity and mortality.
• VENTILATOR-ASSOCIATED PNEUMONIA: Ventilator associated pneumonia is defined as the pneumonia that develops within 48 hrs of tracheal intubation. It accounts for 15 to 20 per cent of all the nosocomial infections but costs highest in terms of economics, mortality and morbidity. Those patients who are critically ill or those who are receiving continuous mechanical ventilation have a high risk of getting infected with ventilator associated pneumonia. Approximately 9 to 27 per cent of the intubated patients develop ventilator-associated pneumonia and nearly 25 to 60 per cent of these are not able to survive.
• INTRAVASCULAR DEVICE-RELATED BLOODSTREAM INFECTIONS: Intravascular device-related bloodstream infections account for approximately 15 per cent of all nosocomial infections. Although bloodstream infections such as septicemia and bacteremia can develop from the infection at other types of infections on some other site in the body but nearly half of them are caused by central venous catheters.
• GASTROINTESTINAL TRACT INFECTIONS: Rotavirus infection is the major threat to the children especially, younger than three years. It causes acute gastroenteritis in hospitalized children. Clostridium difficile is the most important bacterial cause of nosocomial infections in gastrointestinal tract and is often suspected in the patients with diarrhea and recent medical history of antibiotic use (especially, Cephalosporin and Clindamycin).

PREVENTION AND CONTROL OF NOSOCOMIAL INFECTIONS

• Improved national surveillance: It is mandatory to develop efficient surveillance systems for surveillance of nosocomial infections that occur in inpatient as well as outpatient facilities where much healthcare is now given. Surveillances target those infections which are difficult to treat and are expensive in terms of mortality, morbidity and economics.
•  Improved epidemiologic tools: Aseptic techniques and hand washing are the foremost preventive measures. Weinstein RA. in 1991stated that in ICUs, Asepsis is often ignored in the rush of crisis care. Pulsed-field gel electrophoresis has become an important tool in investigating the multi-drug resistant pathogens.
• Risk adjustment: Robert A. Weinstein, 1998 has emphasized on the need to “risk adjust” infection rates so that inter-hospital comparisons are valid. The development of non-invasive infection resistant devices and implementation of the existing infection control measures help in preventing and controlling the nosocomial infections.
• Improved invasive devices: Most of our successes in controlling nosocomial infections rely on the development of non-invasive monitoring devices or improved invasive devices or minimally invasive surgical tools.
• Antibiotic control: Microorganisms are increasingly becoming resistant to the antibiotics and therefore, depleting the antimicrobials available for their treatment. Judicial use of the available antibiotics and proper implementation of the infection preventive measures can be the effective measures to limit the antimicrobial resistance among the pathogens. Aggressive antibiotic control programs are mandatory to combat nosocomial infections. Combination therapy in antimicrobial use is recommended in most of the surveys.
• Development in therapeutics: Physicians should give necessary value to the results of microbiology laboratories. Development of new diagnostic techniques should be encouraged and all the healthcare settings, whether small or large ones should have the required facilities to conduct a range of diagnostic tests. Also, the essential vaccination programs should be efficiently implemented. According to a current schedule, one third of world’s unimmunized children are in India and not even half of the all the Indian children are fully immunized. Vaccination against the vaccine preventable diseases would promote the health and reduce the mortality and morbidity rates. It will prevent the spread of epidemics, reduce the expenses on healthcare, save on the use of antibiotics and also prevent the spread of antibiotic resistance among microorganisms.
• Occupational Safety: Care should be taken when using needles, scalpels and handling sharp instruments after procedures. Also the disposal of these instruments should be carefully done to avoid infection by any blood borne pathogen. Puncture resistant bags must be used for placing sharp articles to be disposed or to be transported to the reprocessing area for sterilization before reuse. The use of mouthpieces and resuscitation bags or other ventilation devices is recommended over mouth-to mouth resuscitation.

Apart from these, personnel education programs, environmental control, patient isolation, hand washing guidelines, wearing gloves, gowns, mask, eye protection and face shields are some of the standard preventive measures.

CONCLUSION

Healthcare settings are the reservoir of numerous infectious agents because of the presence of many patients with different infectious agents under one roof. These are threat not only to the patients but also to the healthcare workers. A healthy human body has its own ways and means to protect itself against the invading microorganisms. It offers physical and chemical barriers to the infection causing microorganisms. But the surgical procedures pave a way for the easy entry of infectious agents into the body. Therefore, immunization, maintenance of proper hygienic conditions, sterilization of soiled equipments and other articles, increased national surveillances and development of non-invasive procedures are some of the measures to prevent the nosocomial infections. The active cooperation of the Healthcare workers for better implementation of the existing preventive and control measures along with the technical advances will contribute much to fight against the nosocomial infections.

“Any Error in this manuscript is silent testimony of the fact that it was a Human Effort”