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Evaluating factors contributing to nosocomial tuberculosis acquisition in healthcare workers
Healthcare workers (HCWs) are at risk of infection with Mycobacterium tuberculosis, related to burden of illness in patient populations and implementation of infection-control measures in healthcare facilities. De Vries G, et al (Infect Control Hosp Epidemiol 2017; 38:976-982) used the Netherlands TB register to identify the cohort of HCWs infected while working in healthcare facilities between 2000 and 2015.
he Netherlands TB is used by the Dutch National TB control program, and includes DNA fingerprinting as well as clinical/epidemiological details of notified cases. The definition of HCWs includes staff employed as welfare workers and working with refugees, asylum seekers or detainees. Data are captured regarding the use of personal protective equipment in healthcare settings.
During the studied period, 131 HCW cases were registered and fulfilled criteria of working in a healthcare setting and having confirmed TB infection (rather than latent infection). Of these, 32 cases (24%) were infected while working in healthcare, 13 (10%) were infected in the community, 42 (32%) were infected abroad, and 44 (34%) did not fulfil a stipulated category. Occupations those HCWs who acquired TB while working in the Netherlands (n=32) included medical doctor (6), nurse (15), bronchoscopy assistant (3), laboratory assistant (1), sterilisation assistant (2), pathology assistant (1), autopsy assistant (1), and medical assistant (1). Twenty of these cases (63%) had pulmonary TB, and 12 (37%) had extra-pulmonary infection. In 15 instances, there was a delayed diagnosis in the index case, and in 17 instances a high-risk procedure was performed by the HCW. High-risk procedures
included bronchoscopy, cleaning of surgical equipment, working in pathology or microbiology laboratory, and irrigation of an extra-pulmonary tuberculous abscess.
Findings demonstrate delayed diagnosis in a TB patient to be the predominant underlying risk factor for nosocomial transmission. Performing high-risk procedures is also a risk factor, and no HCWs acquiring TB had had appropriate infection-control measures in place at the time of procedure. In low-incidence countries, clinician awareness must be improved, in order to avoid delayed diagnosis and inevitable risks to HCWs.
Prevention bundles for reducing Clostridium difficile in inpatient settings
Clostrtidium difficile infection (CDI) poses a major threat to healthcare facilities in Europe and the United States, but control of CDI is often challenging, given multiple potential sources of transmission. Bundled interventions have been used to successfully target other healthcare-associated infections (e.g. CLABSI), but few have evaluated the impact of multimodal prevention strategies for CDI prevention. Barker AK, et al (Infect Control Hosp Epidemiol 2017; 38;639-650) undertook a systematic review to examine bundle components, evaluate compliance with prevention bundles, and to evaluate the efficacy of bundled approaches in reducing CDI rates.
A prevention bundle was defined as any multimodal strategy (>1 intervention) focused on reducing CDI in the inpatient setting. Literature review was performed to identify all published studies up to 30 April 2016, specifically including those reporting CDI rates before and after intervention.
Twenty-six published studies fulfilled inclusion criteria following review of 1242 abstracts and/or full text articles. Twenty of the included studies were interrupted time-series and 6 were quasi-experimental pre/post-intervention studies. Of 10 bundle components, the most frequently employed were: hand-hygiene (88.5%) and environmental cleaning (88.5%), followed by isolation/cohorting (77%), antibiotic stewardship (73%), staff education (73%). Other components were included less frequently: system and workflow changes (54%), dedicated equipment (27%), patient education (19%), and proton-pump inhibitor stewardship (19%). Almost all studies reported adherence for at least 1 component of the bundle, but reporting of compliance was not standardised. All 26 studies demonstrated a decrease in CDI rates, with odds ratios spanning 0.29 to 0.38.
Although multimodal prevention programs for CDI may be effective at a hospital level, it is not possible to adequately perform pooled-study analysis. Given the heterogeneity of bundles, it is unclear of overall reductions in CDI are truly reflective of bundled strategies. Notably, none of the bundle components reported in the reviewed studies are supported by high-level evidence for CDI prevention. Antibiotic stewardship and contact precautions have been classified as having level 2 supporting evidence, and other components have a weaker evidence-base. Looking ahead, standardised definitions for infection and interventions are required in order to improve quality of data and ability to systematically evaluate.
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