Characterize and compare SARS-CoV-2–specific immune responses in plasma and gingival crevicular fluid (GCF) from nursing home residents during and after natural infection

Prospective cohort

Nursing home

SARS-CoV-2–infected nursing home residents

A convenience sample of 14 SARS-CoV-2–infected nursing home residents, enrolled 4–13 days after real-time reverse transcription polymerase chain reaction diagnosis, were followed for 42 days. Post diagnosis, plasma SARS-CoV-2–specific pan-Immunoglobulin (Ig), IgG, IgA, IgM, and neutralizing antibodies were measured at 5 timepoints and GCF SARS-CoV-2–specific IgG and IgA were measured at 4 timepoints.

All participants demonstrated immune responses to SARS-CoV-2 infection. Among 12 phlebotomized participants, plasma was positive for pan-Ig and IgG in all 12, neutralizing antibodies in 11, IgM in 10, and IgA in 9. Among 14 participants with GCF specimens, GCF was positive for IgG in 13 and IgA in 12. Immunoglobulin responses in plasma and GCF had similar kinetics; median times to peak antibody response was similar across specimen types (4 weeks for IgG; 3 weeks for IgA). Participants with pan-Ig, IgG, and IgA detected in plasma and GCF IgG remained positive through this evaluation’s end 46–55 days post-diagnosis. All participants were viral culture negative by the first detection of antibodies.

Nursing home residents had detectable SARS-CoV-2 antibodies in plasma and GCF after infection. Kinetics of antibodies detected in GCF mirrored those from plasma. Non-invasive GCF may be useful for detecting and monitoring immunologic responses in populations unable or unwilling to be phlebotomized.

To characterize healthcare provider diagnostic testing practices for identifying Clostridioides (Clostridium) difficile infection (CDI) and asymptomatic carriage in children.

Electronic survey.

An 11-question survey was sent by e-mail or facsimile to all pediatric infectious diseases (PID) members of the Infectious Diseases Society of America’s Emerging Infections Network (EIN).

Among 345 eligible respondents who had ever responded to an EIN survey, 196 (57%) responded; 162 of these (83%) were aware of their institutional policies for CDI testing and management. Also, 159 (98%) respondents knew their institution’s C. difficile testing method: 99 (62%) utilize NAAT without toxin testing and 60 (38%) utilize toxin testing, either as a single test or a multistep algorithm. Of 153 respondents, 10 (7%) reported that formed stools were tested for C. difficile at their institution, and 76 of 151 (50%) reported that their institution does not restrict C. difficile testing in infants and young children. The frequency of symptom- and age-based testing restrictions did not vary between institutions utilizing NAAT alone compared to those utilizing toxin testing for C. difficile diagnosis. Of 143 respondents, 26 (16%) permit testing of neonatal intensive care unit patients and 12 of 26 (46%) treat CDI with antibiotics in this patient population.

These data suggest that there are opportunities to improve CDI diagnostic stewardship practices in children, including among hospitals using NAATs alone for CDI diagnosis in children.

To define the scope of an outbreak of Legionnaires’ disease (LD), to identify the source, and to stop transmission.

Epidemiologic investigation of an LD outbreak among patients and a visitor exposed to a newly constructed hematology-oncology unit.

An LD case was defined as radiographically confirmed pneumonia in a person with positive urinary antigen testing and/or respiratory culture for Legionella and exposure to the hematology-oncology unit after February 20, 2014. Cases were classified as definitely or probably healthcare-associated based on whether they were exposed to the unit for all or part of the incubation period (2–10 days). We conducted an environmental assessment and collected water samples for culture. Clinical and environmental isolates were compared by monoclonal antibody (MAb) and sequence-based typing.

Over a 12-week period, 10 cases were identified, including 6 definite and 4 probable cases. Environmental sampling revealed Legionella pneumophila serogroup 1 (Lp1) in the potable water at 9 of 10 unit sites (90%), including all patient rooms tested. The 3 clinical isolates were identical to environmental isolates from the unit (MAb2-positive, sequence type ST36). No cases occurred with exposure after the implementation of water restrictions followed by point-of-use filters.

Contamination of the unit’s potable water system with Lp1 strain ST36 was the likely source of this outbreak. Healthcare providers should routinely test patients who develop pneumonia at least 2 days after hospital admission for LD. A single case of LD that is definitely healthcare associated should prompt a full investigation.

Infect Control Hosp Epidemiol 2017;38:306–313

To determine the timing of community-onset Clostridium difficile–associated disease (CDAD) relative to the patient's last healthcare facility discharge, the association of postdischarge cases with healthcare facility–onset cases, and the influence of postdischarge cases on overall rates and interhospital comparison of rates of CDAD.

Retrospective cohort study for the period January 1, 2005, through December 31, 2005.

Catchment areas of 6 acute care hospitals in North Carolina.

We reviewed medical and laboratory records to determine the date of symptom onset, the dates of hospitalization, and stool C. difficile toxin assay results for patients with CDAD who had diarrhea and positive toxin–assay results. Cases were classified as healthcare facility–onset if they were diagnosed more than 48 hours after admission. Cases were defined as community-onset if they were diagnosed in the community or within 48 hours after admission, and were also classified on the basis of the time since the last discharge: if within 4 weeks, community-onset, healthcare facility–associated (CO-HCFA); if 4-12 weeks, indeterminate exposure; and if more than 12 weeks, community-associated. Pearson's correlation coefficient was used to assess the association between monthly rates of healthcare facility–onset, healthcare facility–associated (HO-HCFA) cases and CO-HCFA cases. We performed interhospital rate comparisons using HO-HCFA cases only and using both HO-HCFA and CO-HCFA cases.

Of 1046 CDAD cases, 442 (42%) were HO-HCFA cases and 604 (58%) were community-onset cases. Of the 604 community-onset cases, 94 (15%) were CO-HCFA, 40 (7%) were of indeterminate exposure, and 208 (34%) community-associated. A modest correlation was found between monthly rates of HO-HCFA cases and CO-HCFA cases across the 6 hospitals (r = 0.63, P<.001). Interhospital rankings changed for 6 of 11 months if CO-HCFA cases were included.

A substantial proportion of community-onset cases of CDAD occur less than 4 weeks after discharge from a healthcare facility, and inclusion of CO-HCFA cases influences interhospital comparisons. Our findings support the use of a proposed definition of healthcare facility–associated CDAD that includes cases that occur within 4 weeks after discharge.

The epidemiology of Clostridium difficile-associated disease (CDAD) is changing, with evidence of increased incidence and severity. However, the understanding of the magnitude of and reasons for this change is currently hampered by the lack of standardized surveillance methods.

An ad hoc C. difficile surveillance working group was formed to develop interim surveillance definitions and recommendations based on existing literature and expert opinion that can help to improve CDAD surveillance and prevention efforts.

A CDAD case patient was defined as a patient with symptoms of diarrhea or toxic megacolon combined with a positive result of a laboratory assay and/or endoscopic or histopathologic evidence of pseudomembranous colitis. Recurrent CDAD was defined as repeated episodes within 8 weeks of each other. Severe CDAD was defined by CDAD-associated admission to an intensive care unit, colectomy, or death within 30 days after onset. Case patients were categorized by the setting in which C. difficile was likely acquired, to account for recent evidence that suggests that healthcare facility-associated CDAD may have its onset in the community up to 4 weeks after discharge. Tracking of healthcare facility–onset, healthcare facility–associated CDAD is the minimum surveillance required for healthcare settings; tracking of community–onset, healthcare facility–associated CDAD should be performed only in conjunction with tracking of healthcare facility–onset, healthcare facility–associated CDAD. Community–associated CDAD was defined by symptom onset more than 12 weeks after the last discharge from a healthcare facility. Rates of both healthcare facility–onset, healthcare facility–associated CDAD and community–onset, healthcare facility–associated CDAD should be expressed as case patients per 10,000 patient–days; rates of community-associated CDAD should be expressed as case patients per 100,000 person-years.