Risk factors for hospital-acquired infection during the SARS-CoV-2 pandemic

OBJECTIVE

To evaluate risk factors for hospital-acquired infection (HAI) in patients during the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, including historical and concurrent cohorts.

DESIGN

Retrospective cohort.

SETTING

Three Missouri hospitals, data from 1^st January 2017 to 30^th September 2020.

PARTICIPANTS

Patients aged ≥18 years and admitted for ≥48 h.

METHODS

Univariate and multi-variate Cox proportional hazards models incorporating the competing risk of death were used to determine risk factors for HAI. A-priori sensitivity analyses were performed to assess the robustness of the urine-, blood- and respiratory-culture-based HAI definition.

RESULTS

The cohort included 254,792 admissions, with 7147 (2.8%) HAIs (1661 blood, 3407 urine, 2626 respiratory). Patients with SARS-CoV-2 had increased risk of HAI (adjusted hazards ratio 1.65, 95% confidence interval 1.38-1.96), and SARS-CoV-2 infection was one of the strongest risk factors for development of HAI. Other risk factors for HAI included certain admitting services, chronic comorbidities, intensive care unit stay during index admission, extremes of body mass index, hospital, and selected medications. Factors associated with lower risk of HAI included year of admission (declined over the course of the study), admitting service and medications. Risk factors for HAI were similar in sensitivity analyses restricted to patients with diagnostic codes for pneumonia/upper respiratory infection and urinary tract infection.

CONCLUSIONS

SARS-CoV-2 was associated with significantly increased risk of HAI.

Epidemiology and outcomes of Clostridium difficile infection in allogeneic hematopoietic cell and lung transplant recipients

BACKGROUND

Clostridium difficile infection (CDI) is a common complication of lung and allogeneic hematopoietic cell (HCT) transplant, but the epidemiology and outcomes of CDI after transplant are poorly described.

METHODS

We performed a prospective, multicenter study of CDI within 365 days post-allogeneic HCT or lung transplantation. Data were collected via patient interviews and medical chart review. Participants were followed weekly in the 12 weeks post-transplant and while hospitalized and contacted monthly up to 18 months post-transplantation.

RESULTS

Six sites participated in the study with 614 total participants; 4 enrolled allogeneic HCT (385 participants) and 5 enrolled lung transplant recipients (229 participants). One hundred and fifty CDI cases occurred within 1 year of transplantation; the incidence among lung transplant recipients was 13.1% and among allogeneic HCTs was 31.2%. Median time to CDI was significantly shorter among allogeneic HCT than lung transplant recipients (27 days vs 90 days; P = .037). CDI was associated with significantly higher mortality from 31 to 180 days post-index date among the allogeneic HCT recipients (Hazard ratio [HR] = 1.80; P = .007). There was a trend towards increased mortality among lung transplant recipients from 120 to 180 days post-index date (HR = 4.7, P = .09).

CONCLUSIONS

The epidemiology and outcomes of CDI vary by transplant population; surveillance for CDI should continue beyond the immediate post-transplant period.

Recurrent Clostridium difficile infection is associated with increased mortality

Clostridium difficile infections (CDI) are associated with decreased survival, and up to 30% of CDI patients may experience a recurrence. Data on the impact of recurrent CDI on mortality are scarce. The purpose of this study was to determine whether recurrent CDI was independently associated with decreased 6-month survival compared with patients with CDI who did not develop a recurrence. We performed a retrospective cohort study at an academic, urban, tertiary care hospital. Data were collected from the electronic medical record and chart review. CDI patients were followed for 180 days from the end of their index hospital discharge or end of index CDI antibiotic treatment, whichever was later, to determine mortality. Kaplan-Meier analysis was used to compare patient mortality by recurrent CDI status. Cox proportional hazards models were used to determine independent risk factors for death within 180 days. In all, 3958 patients aged ≥ 18 years who developed an initial CDI episode from 2003 to 2009, including 421 patients with recurrent CDI, were included in the study. Thirty-six per cent of persons with recurrent CDI died within 180 days, compared with 26% of persons without CDI recurrence (log-rank p <0.001). Recurrent CDI was associated with significantly higher hazards of death within 180 days, adjusting for demographics, comorbidities and medications received during the index CDI hospitalization (hazard ratio 1.33; 95% CI 1.12-1.58). Recurrent CDI is associated with significantly increased risk of death within 6 months after completion of their initial CDI treatment compared with CDI patients who do not develop a recurrence.

Epidemiological model for Clostridium difficile transmission in healthcare settings

OBJECTIVE

Recent outbreaks of Clostridium difficile infection (CDI) have been difficult to control, and data indicate that the importance of different sources of transmission may have changed. Our objectives were to evaluate the contributions of asymptomatic and symptomatic C. difficile carriers to new colonizations and to determine the most important epidemiological factors influencing C. difficile transmission.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort study of all patients admitted to medical wards at a large tertiary care hospital in the United States in the calendar year 2008.

METHODS

Data from six medical wards and published literature were used to develop a compartmental model of C. difficile transmission. Patients could be in one of five transition states in the model: resistant to colonization (R), susceptible to colonization (S), asymptomatically colonized without protection against CDI (C(-)), asymptomatically colonized with protection against CDI (C(+)), and diseased (ie, with CDI; D).

RESULTS

The contributions of C(-), C(+), and D patients to new colonizations were similar. The simulated basic reproduction number ranged from 0.55 to 1.99, with a median of 1.04. These values suggest that transmission within the ward alone from patients with CDI cannot sustain new C. difficile colonizations and therefore that the admission of colonized patients plays an important role in sustaining transmission in the ward. The epidemiological parameters that ranked as the most influential were the proportion of admitted C(-) patients and the transmission coefficient for asymptomatic carriers.

CONCLUSION

Our study underscores the need to further evaluate the role of asymptomatically colonized patients in C. difficile transmission in healthcare settings.

The ecology and pathobiology of Clostridium difficile infections: an interdisciplinary challenge

Clostridium difficile is a well recognized pathogen of humans and animals. Although C. difficile was first identified over 70 years ago, much remains unknown in regards to the primary source of human acquisition and its pathobiology. These deficits in our knowledge have been intensified by dramatic increases in both the frequency and severity of disease in humans over the last decade. The changes in C. difficile epidemiology might be due to the emergence of a hypervirulent stain of C. difficile, ageing of the population, altered risk of developing infection with newer medications, and/or increased exposure to C. difficile outside of hospitals. In recent years, there have been numerous reports documenting C. difficile contamination of various foods, and reports of similarities between strains that infect animals and strains that infect humans as well. The purposes of this review are to highlight the many challenges to diagnosing, treating, and preventing C. difficile infection in humans, and to stress that collaboration between human and veterinary researchers is needed to control this pathogen.

Pulmonary zygomycosis in solid organ transplant recipients in the current era

Fifty-eight solid organ transplant recipients with zygomycosis were studied to assess the presentation, radiographic characteristics, risks for extra-pulmonary dissemination and mortality of pulmonary zygomycosis. Pulmonary zygomycosis was documented in 31 patients (53%) and developed a median of 5.5 months (interquartile range, 2-11 months) posttransplantation. In all, 74.2% (23/31) of the patients had zygomycosis limited to the lungs and 25.8% (8/31) had lung disease as part of disseminated zygomycosis; cutaneous/soft tissue (50%, 4/8) was the most common site of dissemination. Pulmonary disease presented most frequently as consolidation/mass lesions (29.0%), nodules (25.8%) and cavities (22.6%). Patients with disseminated disease were more likely to have Mycocladus corymbifer as the causative pathogen. The mortality rate at 90 days after the treatment was 45.2%. In summary, pulmonary zygomycosis is the most common manifestation in solid organ transplant recipients with zygomycosis, and disseminated disease often involves the cutaneous/soft tissue sites but not the brain.

Vancomycin-resistant enterococcal bloodstream infections on a hematopoietic stem cell transplant unit: are the sick getting sicker?

Patients with hematologic malignancies and hematopoietic stem cell transplant (HSCT) recipients are at high risk for bacterial bloodstream infections (BSI) owing to resistant organisms. Data describing the outcomes of vancomycin-resistant enterococcal (VRE) BSI in this patient population are limited. We performed a retrospective cohort study of all cases of VRE BSI that occurred between February 1996 and December 2002 on the Leukemia/HSCT unit at Barnes-Jewish Hospital. There were 68 episodes of VRE BSI in 60 patients with acute (53%) or chronic (8%) leukemia, non-Hodgkin's lymphoma (22%) or other malignant hematologic disorders (17%). A total of 13, 32 and 32% were recipients of autologous, related and matched-unrelated transplants, respectively. Forty-two of allograft recipients had active acute graft-versus-host disease (GVHD) and 32% chronic GVHD. Only 57% were neutropenic, 52% had refractory/relapsed malignancy and 60% had end organ dysfunction with a median APACHE II score of 17. Median survival after VRE BSI was 19 days. Pneumonia, receipt of anti-fungal drugs and low APACHE II score at the time of the VRE BSI remained significant risk factors for death on multivariable analysis. Our analysis suggests that in patients with hematological malignancies or HSCT, VRE may not have the behavior of a virulent pathogen. VRE BSI may simply be a marker of these patients' already existing critical medical condition.