TB infection control measures

INFECTION CONTROL

 

INTRODUCTION

 

            Good health depends in part on a safe environment. Practices or techniques that control or prevent transmission of infection help to protect individuals, especially patients and health care workers from disease. Patients in all health care settings are at risk for acquiring infections because of lower resistance to infectious microorganisms, increased exposure to numbers and types of disease-causing microorganisms, and invasive procedures.

            In acute care or ambulatory care facilities, patients can be exposed to pathogens, some of which may be resistant to most antibiotics. By practicing infection prevention and control techniques, health care workers can avoid spreading microorganisms to patients and fellow health care workers.

            In all settings, the patients and their families must be able to recognize source of infections and be able to institute protective measures. Patient teaching should include information concerning infections, modes of transmission, and methods of prevention.

            Health care workers can protect themselves from contact with infectious material or exposure to a communicable disease by having knowledge of the infectious process and appropriate barrier protection. Diseases such as hepatitis B and C, acquired immunodeficiency syndrome (AIDS), and tuberculosis (TB) have resulted in a greater emphasis on infection-control techniques.

For this paper, a particular situation in an area of practice will be discussed. This is about a patient who has the active form of TB and wherein the infection control procedures of the hospital where the patient is staying needs further evaluation and recommendations regarding their TB infection control measures.

 

MAIN BODY

           

Patient profile

           

            Donald is a 55 year old man who is admitted to the hospital for pulmonary tuberculosis (TB). He has recently been diagnosed since pulmonary TB is asymptomatic in the earliest stages. The symptoms and signs do not usually become apparent until after the lesions appear on the x-ray. He had chronic cough, fever, malaise and weight loss prior to his admission at the hospital which through tests and x-ray it has been found out that he has TB.

            At the moment, Donald is placed on isolation as further tests have to be done regarding his condition. Also, the reason why he has to remain in isolation is that TB is highly transmissible and could infect anyone that comes close to him.

            Donald is not the first patient with TB that has been admitted to the hospital. Yet, the previous cases and how the hospital staff handled each case were rather poor and have resulted to three tuberculin skin test-positive health-care workers. However, these workers have initiated isoniazid therapy. This time, a comprehensive tuberculosis control program has been implemented in the hospital in order to avoid such incidences.

 

Background of the Infection/Disease

 

            Tuberculosis is an acute or chronic infection caused by Mycobacterium tuberculosis and sometimes by Mycobacterium bovis. It is almost always initiated by inhalation. Pulmonary disease is most common, but disease can spread via the lymphatics and bloodstream to any other organ (1998).

            TB is characterized clinically by a lifelong balance between host and infection in which pulmonary or extrapulmonary foci may reactivate at any time, often after long periods of latency; and pathologically by the formation of tubercles made up of giant cells and epithelioid cells, by a tendency of fibrosis to occur, and by caseation, a unique form of nonliquefying necrosis (1998).

One of the most oldest diseases, it was known as consumption or the great white plague. The bacillus infects the lungs by inhalation of infected droplets formed during coughing of an individual with the active form of the disease. In the vast majority of cases, the infection is localized and symptomless, but it may progress to cause chronic pulmonary tuberculosis which is the active form. The bacilli can remain dominant for years before becoming active.

Typical symptoms include fatigue, loss of weight and appetite, night sweats and fever, and persistent cough. Sputum is often streaked with blood; sometimes massive hemorrhages occur as the lung tissue is destroyed by the disease. Fluid may collect in the pleural cavity. Gradual deterioration occurs and, if the disease is untreated, death is common. Tuberculosis may spread from the lungs to any part of the body. M. tuberculosis and other pathogens that infect the respiratory tract can be released from the body when an infected person sneezes, coughs, talks, or even breathes.

            Approximately 1.9 million people around the globe die of TB each year, and another 1.9 billion are infected with Mycobacterium tuberculosis and are at risk for active disease (2006). However, on a purely statistical basis, TB and other lung infections are not among the most common causes of chronic cough, even in countries with a high prevalence of this infection. Nevertheless, because of the contagious nature of TB and its potential for devastating morbidity and mortality for individual patients and society, TB should be considered early in the evaluation of patients especially those with chronic cough when the likelihood of active TB is high.

In geographic areas where the prevalence of TB is high, or in populations at high risk of TB (eg, HIV-seropositive persons who use injection drugs), the diagnosis should be considered in all patients with chronic cough, sputum production, hemoptysis, fever, or weight loss. Some high-risk persons may have TB even with normal physical examination and chest radiograph findings, especially when they are immunocompromised (2006)

            As part of the strategy of the World Health Organization to control TB and other respiratory illnesses, the Practical Approach to Lung Health (PAL) strategy was designed as one component of the global directly observed treatment, short-course program. PAL is a syndrome-based strategy to manage patients with respiratory symptoms, mainly cough of 2 to 3 weeks duration. The program aims to improve the management of respiratory care in health systems with a focus on primary care services to increase TB detection and diagnosis and to improve case management. PAL also attempts to improve the quality of the care of patients with acute respiratory infection with a focus on pneumonia], asthma, and chronic obstructive pulmonary disease ( 2006).

 

Etiology

 

            M. tuberculosis is an acid-fast, nonmotile rod. M. tuberculosis organisms are characteristically sensitive to isoniazid (INH) and produce niacin and the enzyme catalase. INH-resistant mutants of M. tuberculosis generally lose their ability to produce catalase, but remain niacin-positive. M. bovis is also sensitive to INH, but does not produce niacin. All other mycobacteria are highly INH-resistant, catalase-positive, and niacin-negative (2000).

 

Epidemiology

 

            Infection occurs primarily by the aerosol route. Airborne droplets may remain infectious and suspended for long periods of time. They are small and reach the smallest airway without being trapped and removed by bronchial mucosal clearance mechanisms. In areas where bovine TB has not been eliminated, transmission may occur by ingestion of contaminated milk. Direct inoculation occasionally occurs in those who are working in the laboratories (1998).

 

Pathogenesis

 

            A nonsensitized host has no preexisting specific immunologic defense against TB. Therefore, when an infectious particle is inhaled into the terminal air passages, infection occurs and a colony of M. tuberculosis develops, usually in the lower or middle lung fields. With little host reaction and no symptoms, the bacilli spread readily to the draining lymph nodes and, via the bloodstream, throughout the body ( 1998).

            With the development of tuberculin hypersensitivity four to ten weeks later, a small area of pneumonitis develops, further multiplication of intracellular bacilli is inhibited at the initial and metastatic foci, and the infection is usually arrested before symptoms develop. The process is bacteriostatic rather than bactericidal, however, and the bacilli may remain latent but viable for the life of the host. Foci of infection may be reactivated at any time by local factors, especially if cellular immunity wanes due to disease, corticosteroid or other immunosuppressant drug therapy, or old age ( 1998).

            Occasionally, the initial or metastatic infection evolves into clinical TB despite development of hypersensitivity. Local tissue destruction due to nonspecific lung abscess, carcinoma, or pulmonary restriction; local joint tissue injury; gastric resection; and diabetes mellitus, particularly with ketoacidosis, favor progression of disease.

           

Appropriate Infection Control Procedures

 

            A consensus that caring for patients with TB posed a risk to health-care workers did not emerge until the 1950s and 1960s, when studies established that Mycobacterium tuberculosis infection was transmitted by the airborne route. However, occupational transmission received little attention until numerous outbreaks of TB and multidrug-resistant tuberculosis occurred in U.S. and European hospitals in the 1980s and 1990s (2001).

With the increase in numbers of reported cases of TB, health care organizations all over the world have issued different guidelines for prevention and transmission of TB in health care facilities. Regardless the type of isolation system that a patient is in, health care professionals must follow several basic principles.

            Efficient control of hospital-acquired TB is compromised by the same difficulties complicating community control, including an insensitive, slow method of diagnosing active disease; an insensitive, nonspecific method of diagnosing latent disease; and relatively slow-acting, complicated courses of medical therapy. However, enormous strides in hospital TB control were made during the late 1980s and 1990s by using common sense, trial and error, and published guidelines (2001).

Health care professionals, usually the nurse, should use thorough hand hygiene before entering and leaving the room of the patient who in isolation. Contaminated supplies and equipment should be disposed of in a manner that prevents spread of microorganisms to other persons as indicated by the mode of transmission of the organism ( 2004).

            Knowledge of a disease process and the mode of infection transmission should be applied when using protective barriers. All persons who might be exposed during transport of a patient outside the isolation room must be protected (2004).

            When a patient is identified as a TB case or suspect, the patient is placed in an appropriate isolation room. Negative pressure for each isolation room is verified on a quarterly basis. The number of air changes is verified at the time the room is set up as an isolation room, but not routinely thereafter (1998).

Private rooms used for isolation may have negative-pressure airflow to prevent infectious particles from flowing out of the room. The health care professional must remain aware of infection prevention and control techniques while working with patients in protected environments. The health care professional should feel comfortable performing all procedures and yet remain conscious of infection-control procedures ( 2004).

            Personal protective equipment like gowns, masks, protective eyewear, and gloves should be readily available for the personnel performing care for the patient. The primary reason for wearing a gown is to prevent soiling clothes during contact with the patient. Gown or cover-ups protect health care workers and visitors from coming in contact with infected material and blood or body fluid (2004).

            Full face protection should be worn when splashing or spraying of blood or body fluid into face is anticipated. Masks should also be worn when working with a patient placed on airborne or droplet precautions. The mask protects the health care worker from inhaling microorganisms from a patient’s respiratory tract and prevents transmission of pathogens from the health care workers’ respiratory tract to the patient ( 2004).

            Specially fitted respiratory protective devices or masks are required when caring for a patient with known or suspected TB, as is the case of Donald. The mask must have a higher filtration rating than the regular surgical mask and be fitted snugly to the wearer’s face to prevent leakage around sides (2004).

            Many infection control programs lost a degree of credibility and good will in hospitals where clinicians resisted accepting uncomfortable masks. Although compliance was achieved, the consequences of forcing staff to follow an unpopular, unproven regulation should not be minimized. The success of other important infection control functions, such as annual influenza vaccination drives and handwashing initiatives, depends as much on good will as on scientific merit. The effort expended to enforce a single intervention may have affected the success of other programs to control hospital-acquired infections (2001).

            With regards to the isolation of the patient, there is a question as to when it could be discontinued. Discontinuing isolation of patients with known TB often is less important for physicians but of paramount importance to the hospital infection control staff, who need to know when a patient no longer can transmit the tubercle bacillus. Among time-honored approaches (22), the most common is the practice of considering discharge after 2 weeks of apparently effective therapy. Others wait until the sputum smear converts from positive to negative, which may take 4 to 6 weeks. In areas where drug-resistant TB is common, a more cautious approach might be waiting for at least 2 weeks of’ smear-negativity or for culture negativity ( 2001)

 

Further Recommendations

 

A comprehensive tuberculosis control program for health-care facilities reduces the risk of nosocomial tuberculosis and is usually mandated by the appropriate health and safety administration. However, this alone with its infection control measures are not enough. Although effective infection-control measures can greatly decrease the risk of nosocomial tuberculosis infection, the risk of tuberculosis exposure and infection among health-care workers will always be present to some extent ( 2002).

Therefore, screening workers for latent tuberculosis infection, using the appropriate tests, remain an integral part of tuberculosis control programs for health-care facilities. Tuberculin skin testing programs serve two important purposes: to monitor tuberculosis acquisition among health-care workers, and to identify workers with latent tuberculosis infection who need treatment (2002).

Rapid identification of employees with positive tuberculin skin test results should be followed by an evaluation for active tuberculosis disease and appropriate therapy of latent infection.

            Health care workers could also avail of the BCG vaccine. The BCG vaccine is a live vaccine derived from a strain of Mycobacterium bovis that was attenuated by Calmette and Guerin at the Pasteur Institute in France. Many different BCG vaccines are available worldwide. However, BCG vaccination of health care workers should not be used as the primary strategy for two reasons. The protective efficacy of the vaccine in health care workers is uncertain, and even if BCG vaccination is effective in an individual health care worker, other persons in the facility are not protected against possible exposure to and infection with drug-resistant strains of M. tuberculosis ( 1996).

 

 

Conclusion

 

Tuberculosis is a very important health problem that requires the aggressive and interdisciplinary action to prevent and control the spread of the disease. Outbreaks of Mycobacterium tuberculosis have been documented in various environs, even in hospitals. Health care workers are always at risk for tuberculosis exposure and infection when caring for their patients. It is hard to be optimistic about great gains in TB infection control in the years ahead, beyond the current cautious, but effective approach of isolation of infected patients since most programs still continue to rely on inadequate diagnostic tests of TB. Therefore, the most important strategy for controlling tuberculosis still remains the minimizing of the risk for transmission by early identification and treatment of patients who have active infectious tuberculosis. Another strategy is the identification of persons who have latent M. tuberculosis infection and, if indicated, the use of preventive therapy with isoniazid to prevent the latent infection from progressing to active tuberculosis disease. Realizing the significance of the problem and the need to ensure appropriate infection prevention, control, and patient management protocols are important aspects that the hospital should develop for the safety of other patients and the health care workers.

 

 

 

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