10 May 2021

The Clock is Ticking: End Tuberculosis, an Existing Microbial Threat

WHAT IS TUBERCULOSIS?

Tuberculosis (TB) is an airborne bacterial infection caused by Mycobacterium tuberculosis (M. tuberculosis) (Figure 1.) that usually affects the lungs (known as pulmonary TB)^1,2. TB can spread through the inhalation of respiratory droplets of an infected person^1,3. TB is a severe condition that can be fatal if not appropriately treated¹.

Figure 1. Mycobacterium tuberculosis

 

Depending on the airflow in the environment, the respiratory droplets can remain suspended in the air for several hours unless removed by natural or mechanical ventilation⁴. Therefore, daily disinfection of surfaces with mycobactericidal agents is required, particularly in hospitals and clinics⁴.

Did you know there are two types of pulmonary TB infections³?

In most people who inhale M. tuberculosis, the body’s natural immune system can fight the TB infection³. As a result, not everyone infected with TB will become ill³. For those who cannot fight-off TB infection, there are two TB-related conditions that exist³:

• Active TB – Active TB infection refers to when the infection has overcome the body’s immune system, multiplied, and spread to other parts of the body, causing symptoms^3,5.
• Latent TB – Latent TB infection refers to someone who is infected with M. tuberculosis but does not present with active TB symptoms and does not feel ill^3,5. Latent TB can develop into active TB in people whose immune systems have been weakened over their lifetime or due to medical conditions⁵. Refer to table 1 for a comparison of the two TB-related conditions.

 

Active TB infection	Latent TB infection
The bacterial infection has overcome the body’s immune system, multiplied, and spread to other parts of the body3.	The immune system cannot kill the bacterial infection but has managed to prevent spread throughout other parts of the body3,7.
Symptoms will develop within a few weeks or months5.	May never develop TB disease, and the M. tuberculosis can remain inactive for a lifetime7.
General symptoms include: • A bad cough for three weeks or more1. • Coughing up blood1. • Sweating at night1. • The patient usually feels ill1.	Present no symptoms5,7.
The patient is infectious and can spread TB to others7.	The patient is not infectious7.
May have an abnormal chest x-ray, or positive sputum smear (the mucous secreted by cells in the lower airways of the respiratory tract) or culture7.	A chest x-ray will appear normal and a sputum smear will be negative7.
Usually have a positive skin test or blood test indicating TB infection7.	Usually have a positive skin test or blood test indicating TB infection7.
Will require treatment for active TB7.	Will require treatment for latent TB infection to prevent TB from becoming active7.

Table 1. Comparison of active and latent TB infections

 

Did you know TB can also develop in other parts of the body⁵?

It is possible for TB infections to develop in areas outside the lungs (extrapulmonary TB)⁵, such as in the lymph nodes, the bones and joints, the digestive system, the bladder, the reproductive system, and the nervous system⁴. Usually, TB infections in other parts of the body are not infectious⁶ and are more common in people who have a weakened immune system⁵.

WHO IS AT RISK?

All age groups and ethnicities are at risk of TB¹. However, there are risk factors that increase the likelihood of contracting TB including:
• Working or residing with people at high risk for TB in facilities such as hospitals, nursing homes and homeless shelters⁸.
• Underlying medical conditions in young children and immunocompromised individuals such as human immunodeficiency virus (HIV) and diabetes mellitus⁸.
• Misusing alcohol and smoking tobacco⁸.
• Recovering from active TB infection⁸.
• Residing in crowded conditions⁸.
• Residing in or visiting an area with high levels of TB⁸.

WHAT ARE THE MOST COMMON SYMPTOMS OF TB?

Did you know for active TB, the symptoms may be mild for many months leading to delays in seeking medical advice^1,5? – This increases the probability of transmission to others¹.

Common Symptoms of Active Pulmonary TB ^1,3,7

Common Symptoms of Extrapulmonary TB⁵

 

WHY IS TB A MICROBIAL THREAT?

Did you know the COVID-19 pandemic could potentially cause an additional 6.3 million TB cases worldwide by 2025⁹?

The COVID-19 pandemic may reverse all progress made in ending TB⁹. The implementation of social distancing measures may help reduce TB transmission⁹. However, this could be offset by longer durations of infectiousness; increased likelihood of exposure to TB infection within the household; worsening outcomes due to a decrease in care-seeking behaviour of the infected and the extra pressure on health services; and higher levels of poverty, particularly among the most vulnerable populations where severe economic contractions and loss of income occurs⁹. COVID-19 has placed significant financial pressure on the availability of global funding commitments from governments for the TB response⁹. Several countries with resources initially allocated for TB have diverted the funds to the COVID-19 response for their citizens⁹. The combination of TB and COVID-19 effects on a person’s respiratory and immune system could prove to be deadly.

Did you know only two in three people with drug-resistant TB have access to treatment¹⁰?

Multidrug-resistant TB (MDR-TB) has emerged as a global health crisis¹¹. MDR-TB is the consequence of anti-TB medicine misuse, incorrect prescription, low-quality drugs, and patients prematurely stopping treatment¹. MDR-TB patients will not respond to isoniazid and rifampicin, the two most potent first-line anti-TB drugs¹⁰. In this case, second-line TB drugs will be used to treat MDR-TB¹. However, extensively drug-resistant TB (XDR-TB) has also emerged globally, where TB patients do not respond to the most effective second-line anti-TB drugs¹. Although XDR-TB is challenging to treat, it is not impossible¹⁰. A third more severe drug resistance, known as totally drug-resistant TB (TDR-TB), has also developed, often leaving patients without further treatment options¹⁰.

Did you know TB is the leading killer of people with HIV⁸?

TB co-infection with HIV can be a lethal combination to an infected individual¹. People living with HIV are eighteen times more likely to develop active TB¹. HIV weakens the immune system enabling the TB infection to thrive in the body¹. On average, without proper treatment, about 45% of HIV-negative people with TB will die¹. In comparison, nearly all HIV-positive people with TB will die¹. People living with HIV are now dying because of TB, despite the advancements made to improve their quality-of-life¹

THE CLOCK IS TICKING

Everyone is susceptible to TB⁹. People with TB can be found in every country and from all age groups¹. Areas with the highest TB cases include India, Indonesia, China, the Philippines, Nigeria, Pakistan, Bangladesh, and South Africa^1,3. It is estimated 4000 lives are lost daily, 12,000 lives lost monthly, and 1.5 million lost yearly due to TB¹².

Did you know about a quarter of people worldwide are infected with M. tuberculosis and are at risk of developing active TB^1,8?

It is time to act by testing and treating latent and active TB infections¹³. It is time to speak up and eliminate the stigma associated with TB that may prevent people from seeking medical care¹³. This can be done by improving public education and awareness of TB¹³. The hope of having a world free of TB, leading to zero deaths, disease and suffering because of TB, is achievable. However, everyone will have a part to play in preventing the spread of TB worldwide.

 

Table 2. Highlighting positive steps towards eradicating TB and reasons why TB remains a global concern.

PROPRIETIES OF M. TUBERCULOSIS

Mycobacteria species have a unique cell wall and outer membrane composition, which includes: a thick peptidoglycan layer, lipopolysaccharides, embedded glycolipids, wax esters and mycolic acids (long fatty acids chains) that lend to the mycobacterial impermeable barrier^17,18. The mycobacterial cell wall characteristics (Figure 2.) facilitate:

1. Survival in different environments, including biofilms, soils, and water^17,18.
2. Resistance to disinfection procedures as the waxy outer envelope can prevent disinfectant entry to the mycobacterial cell^17,18.

Did you know surfaces and medical devices can be a continuous source of transmission for pathogens such as M. tuberculosis if no regular preventative disinfection is performed?

M. tuberculosis can persist on surfaces for up to four months¹⁹. High-touch surfaces such as door handles, railings, chairs, and table tops may be potential transmission sources. Medical devices that make direct contact with the respiratory system, such as laryngoscopes, bronchoscopes, nasopharyngoscopes, gastrointestinal (GI) manometry catheters and transoesophageal probes, could all be carriers of M. tuberculosis.

 

Figure 2. M. tuberculosis waxy cell envelope

 

AVAILABLE DIAGNOSIS AND TREATMENT

Diagnosis of TB for many countries is assessed by sputum (a mixture of saliva and mucous coughed up from the respiratory tract) smear microscopy¹⁵. This detection method involves trained laboratory technicians examining sputum samples under a microscope to determine if TB mycobacteria are present. However, this method detects only half the number of TB cases and cannot detect TB drug resistance¹⁵.
Rapid molecular diagnostic tests have high diagnostic accuracy and are recommended by the WHO for anyone with signs and symptoms of TB, as the initial diagnostic test¹. The rapid tests lead to significant improvements in the early detection of TB and MDR-TB¹. Xpert MTB/RIF, Xpert Ultra, and Truenat assays are the rapid tests recommended by the WHO¹. TB treatment typically involves the use of multiple
medicines in a variety of combinations¹⁶. The combination will depend on the individual’s circumstances. A first time TB infection will be treated differently from a reoccurring TB infection, and if a residential area is known to have antibiotic resistance to any TB drug treatment¹⁶. Active, drug-susceptible TB is a treatable and curable disease¹. Typically, adherence to a standard six-month³ course of four antimicrobial drugs and support for the patient by a healthcare worker or trained volunteer successfully facilitates recovery⁹. However, treatment adherence can be problematic for people with limited access to TB treatment facilities^9,16. Those who have active MDR-TB contribute to the difficulty healthcare professionals have in successfully treating TB^9,16.

 

PREVENTION AND INFECTION CONTROL MEASURES

Health care interventions available to reduce the risk of TB include:
• Adherence to infection prevention – maintaining good hand hygiene and conducting disinfection of devices and surfaces that can be carriers of TB⁴.
• Preventative TB treatment for latent TB infection⁷.
• Implementing a global multisectoral approach on determinants such as poverty, housing quality and undernutrition to tackle TB⁹.
• Encouraging the reduction in the prevalence of health-related risk factors for TB such as smoking, alcohol misuse, diabetes, and HIV infection, which
can help decrease the number of TB related cases worldwide¹.
• BCG vaccination protects from severe TB in children, especially in countries with a high TB-burden and in households with people living with HIV³.

Did you know people infected with TB can infect up to 15 other people through close contact over a year¹?

If you have been diagnosed with TB, please follow your doctor’s advice to limit the spread. Such advice may include:
• Ensure to take prescribed TB treatment as ineffective treatment can lead to transmission and antibiotic resistance³.
• Ensure to cover the mouth with a tissue when coughing or sneezing and dispose of tissues carefully in a sealed bag³.
• Ensure to wash hands regularly³.
• Ensure to avoid large crowd gathering and public transportation³.
• Do not return to work, school or college until the specialist has confirmed you are no longer infectious³.

 

TRISTEL EFFICACY

Prevent the spread of TB and other pathogens by:
• Ensuring the surfaces in the vicinity of patients and staff are disinfected.
• Ensuring the device is high-level disinfected after each patient use.

Quaternary ammonium compounds (QACs) are less effective against mycobacteria, especially in the presence of protein residues, i.e., soiling.

QACs work by disrupting the cell wall, leading to the cytoplasm leaking out of the cell²¹. QACs mode of action is limited by the mycobacteria’s waxy outer cell walls²¹ (Figure 2.). This is because QAC active components are hindered from causing cell wall disruption to deactivate/destroy mycobacteria²¹. QACs are considered low or intermediate level disinfectants and may require long contact times to achieve the required efficacy level. A surface or device must remain visibly wet for the recommended product contact time during the disinfection process, or reapplication is required. This can be difficult to achieve, especially in the medical environment, where time constraints are critical to reducing patient waiting times and increasing patient turnaround. QACs are not recommended as high-level disinfectants due to their poor efficacy against mycobacteria and spores²².

Tristel’s high-level disinfecting chlorine dioxide-based products, offer a full spectrum of microbial efficacy including against mycobacterium species. Tristel chlorine dioxide-based products are mycobactericidal following the required European Norm (EN) test standards stipulated in EN 14885:2018. Tristel products including Tristel Fuse for Stella (for use with Stella), the Tristel Trio Wipes System, JET and Tristel Fuse for Surfaces have been tested and are proven effective against Mycobacterium terrae and Mycobacterium avium. M. terrae is the surrogate species for M. tuberculosis, and as a result, it is acceptable for a product to claim tuberculocidal efficacy [against TB] when possessing this data. Efficacy against both Mycobacterium species, M. terrae and M. avium, enables a product to be termed ‘mycobactericidal,’inferring efficacy against all Mycobacterium species.

 

USE TRISTEL CHLORINE DIOXIDE PRODUCTS TO PROTECT YOUR DEVICES AND SURFACES

STELLA Quick, mobile, and economic reprocessing of single-lumened and non-lumened, heat-sensitive medical devices. 5-minute contact time.	TRISTEL TRIO WIPES SYSTEM A comprehensive solution for the decontamination of semi-critical, non-lumened medical devices. 30-second contact time.
JET A sporicidal disinfectant foam, ideal for use on high-touch surfaces. 1-minute contact time.	Tristel Fuse for Surfaces A sporicidal disinfectant solution designed for use on large surface areas such as floors and walls. 5-minute contact time.

 

For references see PDF download. ©2021 Tristel Solution Limited. All rights reserved.