Nosocomial transmission of Mycobacterium tuberculosis from an extrapulmonary site

Systematic contact investigation: An essential infection prevention skill to prevent tuberculosis transmission in healthcare settings

A systematic approach to contact investigations has long been a cornerstone of interrupting the transmission of tuberculosis in community settings. This paper describes the implementation of a systematic 10-step contact investigation within an acute care setting during a multistate outbreak of healthcare-associated tuberculosis. A systematic approach to contact investigations might have applicability to the prevention of other communicable infections within healthcare settings.

Mycobacterium tuberculosis Transmission in High-Incidence Settings-New Paradigms and Insights

Tuberculosis has affected humankind for thousands of years, but a deeper understanding of its cause and transmission only arose after Robert Koch discovered Mycobacterium tuberculosis in 1882. Valuable insight has been gained since, but the accumulation of knowledge has been frustratingly slow and incomplete for a pathogen that remains the number one infectious disease killer on the planet. Contrast that to the rapid progress that has been made in our understanding SARS-CoV-2 (the cause of COVID-19) aerobiology and transmission. In this Review, we discuss important historical and contemporary insights into M. tuberculosis transmission. Historical insights describing the principles of aerosol transmission, as well as relevant pathogen, host and environment factors are described. Furthermore, novel insights into asymptomatic and subclinical tuberculosis, and the potential role this may play in population-level transmission is discussed. Progress towards understanding the full spectrum of M. tuberculosis transmission in high-burden settings has been hampered by sub-optimal diagnostic tools, limited basic science exploration and inadequate study designs. We propose that, as a tuberculosis field, we must learn from and capitalize on the novel insights and methods that have been developed to investigate SARS-CoV-2 transmission to limit ongoing tuberculosis transmission, which sustains the global pandemic.

Tuberculosis among prisoners & health care workers

TB in prisons and among HCW is a major public health concern in countries having high burden of disease. Prompt detection of TB is must in prisons by screening on entry, passive screening, mass screening and contact screening via clinical evaluation, smear microscopy and chest X-rays. The new rapid diagnostic methods - True-NAAT, CBNAAT and Line Probe Assay are important tools in the diagnosis. Implementation of effective preventive measures at every steps in various settings, along with airborne infection control and protective measures for staff must be ensured.

Potential Nosocomial Exposure toMycobacterium tuberculosisFrom a Bronchoscope

Objective:

To investigate a possible nosocomial outbreak of tuberculosis (TB).

Design:

Retrospective cohort study.

Setting:

Community hospital.

Methods:

We reviewed medical records, hospital infection control measures, and potential locations of nosocomial exposure. We examined the results of acid-fast bacilli (AFB) smears, cultures, and drug susceptibility testing, and performed a DNA fingerprint analysis. We observed laboratory specimen processing procedures and bronchoscope disinfection procedures. We also reviewed bronchoscopy records.

Results:

In October 2000, three patients had bronchoscopy specimen cultures that were positive forMycobacterium tuberculosis.Of the three, only one had clinical signs and symptoms consistent with TB and positive AFB sputum smears. The other two did not have signs and symptoms consistent with TB and had no known exposure to individuals with infectious TB. The threeM. tuberculosisisolates had matching DNA fingerprints. No evidence of laboratory cross-contamination was identified. The three culture-positive specimens ofM. tuberculosiswere collected with the same bronchoscope within 9 days. This bronchoscope was inadequately cleaned and disinfected between patients, and the automated reprocessor used was not approved for use with the hospital bronchoscope.

Conclusions:

One of the bronchoscopes at this hospital was contaminated withM. tuberculosisduring bronchoscopy of an AFB-smear-positive patient. Subsequent specimen contamination likely occurred because the bronchoscope had been inadequately cleaned and disinfected. Patients who subsequently underwent bronchoscopy were also potentially exposed toM. tuberculosisfrom this bronchoscope.

In-hospital airborne tuberculous infection from a lesion of calcified pleural thickening during thoracic surgery in a patient with lung cancer

A 75-year-old Japanese man underwent thoracic surgery to treat a large lung cancer lesion in the left upper lobe with calcified pleural thickening. Postoperatively, viable Mycobacterium tuberculosis was detected in the margin of the resected thickened calcified pleural lesion. Therefore, an infection control investigation of medical staff who had come in contact with the patient was conducted. Consequently, two of the 14 healthcare professionals who had been in the operating room were diagnosed with latent tuberculous infections. Therefore, strict precautions against airborne infections are required to prevent the in-hospital transmission of M. tuberculosis in such cases.

Infection control for extrapulmonary tuberculosis at a tertiary care cancer center

Extrapulmonary tuberculosis (TB) can be infectious when diagnostic or therapeutic procedures are performed on infected lesions. We retrospectively describe infection control and evaluate isolation failure rates during the manipulation of active extrapulmonary TB lesions at a comprehensive cancer center over a 5-year period. Among patients with a high suspicion of cancer, extrapulmonary TB was not suspected, and airborne precautions often were not used when manipulating infected lesions.

Tuberculose em profissionais de saúde: um novo olhar sobre um antigo problema

Este artigo tem o objetivo de contribuir para o debate sobre a transmissão nosocomial da TB em profissionais de saúde em um país onde esta é endêmica. Verificamos que até 1900 não se aceitava que os profissionais envolvidos no cuidado de pacientes portadores de TB pudessem ser mais susceptíveis à infecção pelo bacilo que a população geral. Vários estudos entre 1920 e 1930 apresentaram achados significativos nas taxas de conversão do teste tuberculínico dos estudantes da área de saúde, mas a maioria dos clínicos continuava se recusando a reconhecer a suscetibilidade dos profissionais de saúde em relação à TB. Nos diferentes locais onde o cuidado ao paciente com TB foi implantado, os profissionais de saúde são descritos como uma população especialmente exposta ao risco de contrair a infecção e adoecer. É urgente que a comunidade científica e os trabalhadores de saúde se organizem, que se reconheçam como uma população sujeita ao risco de adoecimento, e que ações se efetivem no sentido de minimizar os riscos potenciais nos locais onde acontece o cuidado a pacientes com TB.

Cervical tuberculosis: a decision tree for protecting healthcare workers

OBJECTIVES/HYPOTHESIS

The clinical presentation of cervical tuberculosis (TB) is a unique challenge to the otolaryngologist. To minimize the risk of nosocomial transmission, otolaryngologists must suspect the diagnosis and be familiar with recommendations for TB prevention.

STUDY DESIGN

Scientific review.

METHODS

We review current literature and recent changes in TB prevention strategies including the Centers for Disease Control and Prevention "Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005."

RESULTS

Nosocomial transmission may occur from either unrecognized pulmonary disease or from aerosolization of tubercle bacilli during diagnostic procedures. History of prior TB infection, residence in a country where TB is endemic, close contact with a TB patient, or positive tuberculin skin test should raise suspicion of cervical TB. Physical examination findings may include painless, unilateral cervical lymphadenopathy. Children and human immunodeficiency virus infected patients present unique challenges, as these groups may have atypical presentations. When cervical TB is suspected, the provider should always screen for pulmonary and laryngeal disease. Fine needle aspiration with polymerase chain reaction or culture may accurately identify cervical TB. In rare cases, excisional biopsy may be required.

CONCLUSIONS

To facilitate interpretation and rapid diagnosis while minimizing risk to health care providers, we provide a decision tree based on new federal guidelines and the clinical experience of a team of infectious disease specialists and otolaryngologists.

Pilot study of directional airflow and containment of airborne particles in the size of Mycobacterium tuberculosis in an operating room

BACKGROUND

Containment of airborne microorganisms to prevent transmission in a positively pressured operating room (OR) is challenging. Occupational transmission of Mycobacterium tuberculosis (M tuberculosis) to perioperative personnel has occurred, but protection of the surgical site is of equal importance. High-efficiency particulate air (HEPA) filters can mitigate occupational exposure and improve air quality. Smoke plumes and submicron particulates were released to simulate aerobiology of M tuberculosis and assess impact and efficacy of particle removal in an OR suite using different HEPA filtration units and configurations.

OBJECTIVES

My objectives were to compare the impact of freestanding HEPA filter units, which are currently more commonly deployed inside the OR, with a novel portable anteroom system (PAS)-HEPA combination unit (PAS-HEPA) placed outside the OR and assess the efficiency of removal of particulates from an OR.

METHODS

Smoke plume and submicron particles were generated inside an OR. Plume behavior was observed during deployment of 3 different configurations of HEPA units. Two of these involved different models of freestanding HEPA filtration units inside the OR, and the third was the PAS-HEPA unit located outside the OR. The concentration of submicron airborne particles was quantified for each configuration of freestanding HEPA and PAS-HEPA units. In addition to measurement of submicron airborne particulates, a high concentration of these was generated in the OR, and time for removal was quantified.

RESULTS

Observations of released plumes, using the PAS-HEPA unit revealed a downward evacuation, away and toward the main entry door from the sterile field. By contrast, when portable freestanding HEPA units were placed inside the OR, plumes moved vertically upward and directly into the breathing zone of where the surgical team would be stationed during a procedure. The PAS-HEPA unit, working in tandem with the OR heating, ventilation, and air conditioning system, was confirmed to have removed over 94% of an initial release of at least 500,000 submicron particles/ft(3) within 20 minutes after release.

CONCLUSION

This pilot study clearly indicates that avoiding the use of freestanding HEPA filters inside an OR during a surgical procedure is prudent and consistent with Centers for Disease Control and Prevention guidelines. A PAS-HEPA unit is effective in removing submicron particles and will enhance safety of care of a patient with an airborne infection requiring surgery.

[Prevention of tuberculosis in care settings]

INTRODUCTION

The hospital is a favourable setting for the transmission of tubercle bacilli. The presence of susceptible subjects, often immunocompromised, increases the dangers. This risk extends to the patients' visitors and to the staff. It is therefore the responsibility of the hospital to establish preventative measures capable of reducing the risk of transmission or to reduce the effects by appropriate management of exposed subjects.

BACKGROUND

The modes and vectors of transmission are well established. The standardised prevention of transmission is achieved by isolation, the indications and duration of which are based on incomplete information. The surveillance of the carers by the doctor in charge, is based on precise recommendations depending on the risk of exposure.

VIEWPOINT

The objectives are a reduction diagnostic delay, a better determination of infectivity and its duration during treatment, and a more complete census of cases of hospital acquired tuberculosis.

CONCLUSIONS

The management of tuberculosis in hospital requires co-ordination of all involved including those outside the institution and a deliberate policy in the institution itself.

Transmission of tuberculosis from smear negative patients: a molecular epidemiology study

BACKGROUND

While smear positive patients with tuberculosis (TB) are considered more infectious than smear negative patients, the latter can also transmit TB.

METHODS

In a molecular epidemiology study of 791 patients in the Greater Vancouver regional district, the number of episodes of TB transmission from two groups of smear negative clustered patients by RFLP (assumed to be involved in recent transmission) was estimated after assessing for potential bias. Group 1 (n = 79) included patients with pulmonary TB or pulmonary + extrapulmonary disease (PTB or PTB+EPTB); group 2 (n = 129) included all patients in group 1 + extrapulmonary cases alone.

RESULTS

In the total sample the mean (SD) age was 51 (21) years, 54.3% were male, and 17.0% of patients were clustered. Compared with smear negative patients, smear positive patients were more likely to be in a cluster (OR = 2.0, 95% CI 1.1 to 3.6) and to have had a history of ethanol abuse (OR = 2.7, 95% CI 1.0 to 6.7), diabetes mellitus (OR = 2.8, 95% CI 1.1 to 7.0), injection drug use (OR = 3.1, 95% CI 1.1 to 8.3), and to have had a previous hospital admission (OR = 8.5, 95% CI 5.1 to 14.0). The proportion of episodes of transmission from smear negative clustered patients ranged from 17.3% to 22.2% in group 1 and from 25% to 41% in group 2.

CONCLUSION

In Greater Vancouver, smear negative cases appear responsible for at least one sixth of culture positive episodes of TB transmission.

Is cutaneous tuberculosis infectious? A case presentation and practical management plan

Infection control measures for cutaneous tuberculosis in the absence of pulmonary disease are problematic. Delays in diagnosis can lead to the exposure of many individuals. This article describes a case of cutaneous tuberculosis and the subsequent contact investigation. Strategies for infection control and their practicality are discussed.

Tuberculous otitis media with mastoiditis and central nervous system involvement

Tuberculosis of the middle ear and mastoid is currently a rare disease in developed countries, but this disease still occurs and may cause serious consequences. We report a case of disseminated tuberculosis involving the middle ear, mastoid, lung and central nervous system. Tuberculosis should be considered in the differential diagnosis of chronic ear drainage, especially in young children.