Methodologic challenges and lessons learned through conducting a hospital-based Salmonella Javiana case-control study

OBJECTIVE

Determine the food(s) most likely contaminated by Salmonella Javiana associated with a salmonellosis outbreak involving 2 hospitals in North Carolina that were within 50 miles of each other in November 2021.

METHODS

A 2:1 matched case-control study was conducted. Food histories were obtained from hospital food orders and potential confounder covariates were collected from patient medical records. Attack rates and conditional logistic regression odds ratios (OR) were estimated at the 80% confidence interval (CI) for each food exposure and salmonellosis.

RESULTS

There were 21 cases and 42 controls included. Fruit cups had the strongest association with salmonellosis (matched and adjusted OR = 7.9 80% CI: 2.7, 23.6). Hospital-specific ORs varied for several food items, but attack rates analyses provided additional evidence that fruit cups were a likely common source.

CONCLUSION

Our analyses implicated fruit cups in an outbreak of salmonellosis in 2 hospitals. Other methodologic challenges included selection of controls among sick patients, heterogeneity of food exposures, reliance on food orders rather than foods consumed, and retention of food history records. Understanding and anticipating these challenges through changes to policies and operational procedures is critical for conducting efficient and effective case-control studies in the hospital setting.

Healthcare Associated Measles outbreak in pediatric wards in a tertiary care hospital; challenges and Swiss cheese model enforcement for patient safety

INTRODUCTION

Measles is one of the most contagious of all infectious diseases, for example, up to nine out of ten susceptible people with close contact to a measles patient will develop measles. In countries where measles is rare, transmissions in healthcare facilities have been a key factor in amplifying outbreaks OBJECTIVES: describe the hospital transmission of measles among unvaccinated children in pediatric service, challenges faced and recommendations for healthcare settings by applying the Swiss cheese model.

METHOD

Between December, 9th 2019 and January 24th 2020, multiple exposures to measles cases occurred. The incident and factors that led to the outbreak are described. The MF-NCR sequence analysis was also conducted on the three strains isolated from the cases.

RESULTS

The outbreak extended from December 9^th 2019 to January 24^th 2019, which resulted in 110 exposed individuals (85 HCWs and 25 patients). Eleven (44%) children exposed were vaccinated, 14 (56%) were not yet vaccinated and the measles status of 10 (11.8%) HCWs was not known at the time of the outbreak. Two infants acquired measles in the hospital, and both required ICU care. Three infants and one HCW received immunoglobulin. The phylogenetic tree of the MF-NCR sequencing confirmed that all three cases had 100% identical Measles strain.

CONCLUSION

In countries where measles elimination goals are achieved, a multifaceted approach to prevent measles transmission in healthcare is vital to maintain patient safety.

Nurses' knowledge, practices and perceptions regarding Clostridioides difficile: Survey results

BACKGROUND

Clostridioides difficile infection (CDI) can cause patients debilitating symptoms, places additional demands on nurses' and midwives' and is increasingly prevalent. Understanding the knowledge base of nurses caring for patients with CDI may contribute to improving care practices.

METHODS

A cross-sectional anonymous survey across our Hospital and Health Services was conducted. Descriptive statistics and thematic analysis techniques were used to analyse, summarise, and report data.

RESULTS

A total of 198 completed surveys by nurses were included in the analysis. Most respondents (73.2%) could not recall having any recent CDI education. Nearly all agreed that CDI is an important infection control issue (80. 8%), and that CDI education was important (94.9%). Knowledge of the potentially fatal outcome of CDI was not well known with only 53% responding correctly to this question. Respondents were confident in fundamental infection control precautions of patient placement (93.4%) and environmental cleaning (86.4%). Knowledge of the microbiological aspects of CDI were less well known. The impact to workload and the additional burden of caring for patients with CDI was evident in the overwhelming response (83%) to the two open-ended questions about what makes it "easy" and what make it "hard" to implement infection control strategies for CDI patients.

CONCLUSION

Respondents identified many factors that could contribute to less-than optimal care and management of inpatients with CDI, and identified some solutions that would facilitate the provision of best practice. An educational intervention, with emphasis on the areas of greatest knowledge deficits, has been developed.

Containment of COVID-19 and reduction in healthcare-associated respiratory viral infections through a multi-tiered infection control strategy

BACKGROUND

During the ongoing COVID-19 pandemic, healthcare-associated transmission of respiratory viral infections (RVI) is a concern. To reduce the impact of SARS-CoV-2 and other respiratory viruses on patients and healthcare workers (HCWs) we devised and evaluated a multi-tiered infection control strategy with the goal of preventing nosocomial transmission of SARS-CoV2 and other RVIs across a large healthcare campus.

METHODS

From January-June 2020, a multi-tiered infection control strategy was implemented across a healthcare campus in Singapore, comprising the largest acute tertiary hospital as well as four other subspecialty centres, with more than 10,000 HCWs. Drawing on our institution's experience with an outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003, this strategy included improved patient segregation and distancing, and heightened infection prevention and control (IPC) measures including universal masking. All symptomatic patients were tested for COVID-19 and common RVIs.

RESULTS

A total of 16,162 admissions campus-wide were screened; 7.1% (1155/16,162) tested positive for COVID-19. Less than 5% of COVID-19 cases (39/1155) were initially detected outside of isolation wards in multi-bedded cohorted wards. Improved distancing and enhanced IPC measures successfully mitigated onward spread even amongst COVID-19 cases detected outside of isolation. COVID-19 rates amongst HCWs were kept low (0.13%, 17/13,066) and reflected community acquisition rather than nosocomial spread. Rates of healthcare-associated-RVI amongst inpatients fell to zero and this decrease was sustained even after the lifting of visitor restrictions.

CONCLUSION

This multi-tiered infection control strategies can be implemented at-scale to successfully mitigate healthcare-associated transmission of respiratory viral pathogens.

Case-Case Comparison of Candida auris Versus Other Candida Species Bloodstream Infections: Results of an Outbreak Investigation in Colombia

BACKGROUND

Candida auris is an emerging multidrug-resistant yeast that causes outbreaks in healthcare settings around the world. In 2016, clinicians and public health officials identified patients with C. auris bloodstream infections (BSI) in Colombian healthcare facilities. To evaluate potential risk factors and outcomes for these infections, we investigated epidemiologic and clinical features of patients with C. auris and other Candida species BSI.

METHODS

We performed a retrospective case-case investigation in four Colombian acute care hospitals, defining a case as Candida spp. isolated from blood culture during January 2015-September 2016. C. auris BSI cases were compared to other Candida species BSI cases. Odds ratio (OR), estimated using logistic regression, was used to assess the association between risk factors and outcomes.

RESULTS

We analyzed 90 patients with BSI, including 40 with C. auris and 50 with other Candida species. All had been admitted to the intensive care unit (ICU). No significant demographic differences existed between the two groups. The following variables were independently associated with C. auris BSI: ≥ 15 days of pre-infection ICU stay (OR: 5.62, CI: 2.04-15.5), evidence of severe sepsis (OR: 3.70, CI 1.19-11.48), and diabetes mellitus (OR 5.69, CI 1.01-31.9).

CONCLUSION

Patients with C. auris BSI had longer lengths of ICU stay than those with other candidemias, suggesting that infections are acquired during hospitalization. This is different from other Candida infections, which are usually thought to result from autoinfection with host flora.

Missed diagnosis of Clostridium difficile infection; a prospective evaluation of unselected stool samples

BACKGROUND

Clostridium difficile infection (CDI) is the leading cause of hospital-acquired diarrhoea in developed countries, however a high proportion of CDI episodes go undiagnosed, either because physicians do not request identification of toxigenic C. difficile or microbiologists do not perform the appropriate tests.

OBJECTIVE

To investigate the clinical characteristics of patients with CDI within a non-selected population and to determine risk factors for clinical underdiagnosis.

METHODS

We conducted a prospective study in which systematic testing for toxigenic C. difficile on all diarrhoeic stool samples was performed regardless of the clinician's request. Patients aged >2 years positive for toxigenic C. difficile and diarrhoea were enrolled (Jan-June 2013) and monitored at least 2 months after their last episode.

RESULTS

We identified 204 cases of CDI, of which three-quarters were healthcare-associated. Most cases were mild to moderate (83.8%), the recurrence rate was 16.2%, and CDI-related mortality was low (2.5%). A significant proportion (12.7%) of CDI cases would have been missed owing to lack of clinical suspicion. Community-acquired cases and young age were risk factors for clinical underdiagnosis.

CONCLUSION

Our data support the introduction of a systematic search for toxigenic C. difficile in all diarrhoeic stools from inpatients and outpatients older than 2 years.

Viral infections in pregnancy: advice for healthcare workers

BACKGROUND

Healthcare workers (HCWs) have the potential for increased exposure to infectious disease resulting from the provision of patient care. Pregnancy can confer specific problems in some infections for the mother and her unborn child.

AIMS

To discuss the viral infections encountered in the UK that constitute a particular risk to the pregnant HCW: human immunodeficiency virus, hepatitis B virus, hepatitis C virus, varicella-zoster virus, herpes simplex virus, human parvovirus B19, cytomegalovirus, rubella, measles, enteroviruses, mumps and influenza. Evidence for nosocomial transmission, clinical aspects specific to pregnancy, and recommendations to protect the pregnant HCW at work are included.

METHODS

Medline, EMBASE and Pubmed were searched using a list of keywords specific to each viral infection, including 'nosocomial', 'occupational' and 'healthcare workers'. References from the bibliographies of articles identified were reviewed for relevant material.

FINDINGS

The evidence for increased risk in the healthcare setting for many of these infections, outside of outbreaks, is weak, possibly because of the application of standard protective infection control measures or because risk of community exposure is greater. The pregnant HCW should be advised on protective behaviour in both settings. Potential interventions include vaccination and reducing the likelihood of exposure through universal precautions, infection control and redeployment.

CONCLUSION

Protection of the pregnant HCW is the responsibility of the individual, antenatal care provider and employer, and is made possible through awareness of the risks and potential interventions both before and after exposure. If exposure occurs or if the HCW develops an infective illness, urgent specialist advice is required.