Asymptomatic patients colonized with toxigenic Clostridioides difficile are at risk of progressing to C. difficile infection (CDI), but risk factors associated with progression are poorly understood. The objectives of this study were to estimate the incidence and identify risk factors to progression of hospital-onset CDI (HO-CDI) among colonized patients.

This was a nested case-control study at an academic medical center including adult patients colonized with toxigenic C. difficile, detected via polymerase chain reaction (PCR) on a rectal swab collected on admission from 2017 to 2020. Patients with prior CDI or symptoms on admission, neutropenia, prior rectal surgery, or hospitalization less than 24 hours were excluded. Colonized patients that developed HO-CDI were matched 1:3 to colonized patients who did not based on PCR test date. Bivariate and multivariable-adjusted Cox regression analyses were used to identify risk factors.

Of 2,150 colonized patients, 109 developed HO-CDI, with an incidence of 5.1%. After exclusions, 321 patients (69 with HO-CDI) were included, with an estimated incidence of 4.2%. Risk factors included cirrhosis (aHR 1.94), ICU admission (aHR 1.76), malignancy (aHR 1.88), and hospitalization within six months (aHR 1.6). Prior antibiotic exposure in the past three months (aHR 2.14) and receipt of at-risk antibiotics were also identified as potential risk factors (aHR 2.17).

Progression to HO-CDI among colonized patients was not uncommon. This study highlights key risk factors associated with progression, underscoring the importance of enhanced monitoring and prevention efforts tailored to high-risk populations to mitigate HO-CDI.

Coronavirus disease 2019 (COVID-19) vaccination effectiveness in healthcare personnel (HCP) has been established. However, questions remain regarding its performance in high-risk healthcare occupations and work locations. We describe the effect of a COVID-19 HCP vaccination campaign on SARS-CoV-2 infection by timing of vaccination, job type, and work location.

We conducted a retrospective review of COVID-19 vaccination acceptance, incidence of postvaccination COVID-19, hospitalization, and mortality among 16,156 faculty, students, and staff at a large academic medical center. Data were collected 8 weeks prior to the start of phase 1a vaccination of frontline employees and ended 11 weeks after campaign onset.

The COVID-19 incidence rate among HCP at our institution decreased from 3.2% during the 8 weeks prior to the start of vaccinations to 0.38% by 4 weeks after campaign initiation. COVID-19 risk was reduced among individuals who received a single vaccination (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.40–0.68; P < .0001) and was further reduced with 2 doses of vaccine (HR, 0.17; 95% CI, 0.09–0.32; P < .0001). By 2 weeks after the second dose, the observed case positivity rate was 0.04%. Among phase 1a HCP, we observed a lower risk of COVID-19 among physicians and a trend toward higher risk for respiratory therapists independent of vaccination status. Rates of infection were similar in a subgroup of nurses when examined by work location.

Our findings show the real-world effectiveness of COVID-19 vaccination in HCP. Despite these encouraging results, unvaccinated HCP remain at an elevated risk of infection, highlighting the need for targeted outreach to combat vaccine hesitancy.

To describe the pattern of transmission of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) during 2 nosocomial outbreaks of coronavirus disease 2019 (COVID-19) with regard to the possibility of airborne transmission.

Contact investigations with active case finding were used to assess the pattern of spread from 2 COVID-19 index patients.

A community hospital and university medical center in the United States, in February and March, 2020, early in the COVID-19 pandemic.

Two index patients and 421 exposed healthcare workers.

Exposed healthcare workers (HCWs) were identified by analyzing the electronic medical record (EMR) and conducting active case finding in combination with structured interviews. Healthcare coworkers (HCWs) were tested for COVID-19 by obtaining oropharyngeal/nasopharyngeal specimens, and RT-PCR testing was used to detect SARS-CoV-2.

Two separate index patients were admitted in February and March 2020, without initial suspicion for COVID-19 and without contact or droplet precautions in place; both patients underwent several aerosol-generating procedures in this context. In total, 421 HCWs were exposed in total, and the results of the case contact investigations identified 8 secondary infections in HCWs. In all 8 cases, the HCWs had close contact with the index patients without sufficient personal protective equipment. Importantly, despite multiple aerosol-generating procedures, there was no evidence of airborne transmission.

These observations suggest that, at least in a healthcare setting, most SARS-CoV-2 transmission is likely to take place during close contact with infected patients through respiratory droplets, rather than by long-distance airborne transmission.

The use of a clinical prediction score to improve the practice of instituting airborne-transmission precautions in patients with suspected tuberculosis holds promise for increasing appropriate isolation and decreasing unnecessary isolation. The objective of this study was to derive and validate a clinical prediction score for patients with suspected tuberculosis.

We used a case—control study design to evaluate differences between patients with a diagnosis of tuberculosis and those placed under airborne precautions who had negative culture results. We developed risk scores based on a multivariable analysis of independently significant factors associated with tuberculosis. Subsequently, we evaluated the sensitivity and specificity of the score in a separate (validation) cohort of patients.

Within our population, we found 4 clinical factors associated with tuberculosis: chronic symptoms (odds ratio [OR], 10.2 [95% confidence interval {CI}, 2.95-35.4]), upper lobe disease on chest radiograph (OR, 5.27 [95% CI, 1.6-17.23]), foreign-born status (OR, 7.01 [95% CI, 2.1-23.8]), and immunocompromised state other than human immunodeficiency virus infection (OR, 8.14 [95% CI, 2.08-31.8]). Shortness of breath (OR, 0.13 [95% CI, 0.04-0.45]) was found to be associated with non-tuberculosis diagnoses and considered a negative predictor in the model. Using a cut-off point to maximize sensitivity, we applied the prediction rule to the validation cohort, resulting in a sensitivity of 97% and a specificity of 42%.

The tuberculosis prediction rule derived from our patient population could improve utilization of airborne precautions. Clinical prediction rules continue to show their utility for improvement in isolation practices in different demographic areas.

To examine the usefulness of temporal and spatial analysis in identifying nosocomial transmission of Clostridium difficile among pediatric patients hospitalized on four wards at The Children's Hospital of Central California from September 8,1998, to January 16,1999.

Stool specimens obtained from the clinical microbiology laboratory during the study period were tested by culture and latex agglutination for C. difficile. Polymerase chain reaction was used to identify toxin genes. Isolates obtained were mapped to a grid for each ward and were analyzed using the Knox test. Results were compared with DNA fingerprints generated by arbitrarily primed polymerase chain reaction.

Total occupancy of these 4 wards was 438 during the study period. Stool specimens were available for 256 (58%) of these patients, yielding 67 C. difficile isolates and generating 2,211 case pairs for analysis by the Knox test. After stratification by toxin status, 5 clustered pairs of toxigenic isolates were identified on 1 of the wards by this method. Fingerprint analysis identified 4 clusters with indistinguishable banding patterns on 2 of the 4 wards. Two of the identified clusters were toxigenic and 2 were nontoxigenic. None of these clusters corresponded to clusters identified by the Knox test.

The Knox test is an ineffective method for identifying cases resulting from nosocomial transmission of C. difficile in a pediatric setting due to the persistence of C. difficile spores and the unique environment of a pediatric hospital. Molecular analysis remains the most effective method.

To determine risk factors for patients whose cultures grew Stenotrophomonas maltophilia.

Retrospective case-control study of 60 patients with cultures positive for S maltophilia, matched by specimen site to 120 controls whose cultures grew other gram-negative aerobic bacteria.

University medical center.

S maltophilia was identified from the following sites: respiratory (36), wound (13), urinary (6), blood (4), and cerebral spinal fluid (1). By univariate analysis, cases had a higher risk of exposure than controls for ampicillin (P<.001), gentamicin (P<.001), vancomycin (P=.001), metronidazole (P=.003), piperacillin (P=.007), cefotaxime (P=.014), ceftazidime (P=.017), ciprofloxacin (P=.030), tobramycin (P=.040), and chronic respiratory disease (P=.024). Length of time foreign objects were in place prior to positive culture differed significantly between cases and controls only for endotracheal tubes in patients with respiratory isolates (median number of days: 12.5 for cases, 5 for controls; P=.007). For patients with urinary tract infections, having a urinary catheter increased the odds of infection 10 times over controls. Exposures found by multivariate analysis to be significantly more prevalent in cases than controls included ampicillin, cefotaxime, erythromycin, gentamicin, metronidazole, piperacillin, tobramycin, chronic respiratory disease, and female gender. Odds ratios were >1 indicating higher risk for cases, except for erythromycin, which had an odds ratio <1.

The primary risk factor associated with isolation of S maltophilia was antibiotic use. For patients with pulmonary infections, chronic respiratory disease and length of time an endotracheal tube was in place also contributed to the risk. This suggests that judicious use of antibiotics may prevent some cases of S maltophilia infection.