Estimating COVID-19 Vaccine Effectiveness for Skilled Nursing Facility Healthcare Personnel, California, USA.

We estimated real-world vaccine effectiveness among skilled nursing facility healthcare personnel who were regularly tested for SARS-CoV-2 infection in California, USA, during January‒March 2021. Vaccine effectiveness for fully vaccinated healthcare personnel was 73.3% (95% CI 57.5%-83.3%). We observed high real-world vaccine effectiveness in this population.

Workplaces Most Affected by COVID-19 Outbreaks in California, January 2020-August 2021.

Objectives. To describe which industries have the highest burden of COVID-19 outbreaks in California. Methods. We assigned US census industry codes to COVID-19 outbreaks reported to the California Department of Public Health (CDPH) from January 1, 2020, to August 31, 2021, and determined numbers of outbreaks, numbers of outbreak-associated cases, and outbreak incidence levels by industry. We determined characteristics of outbreak-associated cases using individual case data linked to COVID-19 outbreaks. Results. Local health departments reported 19 893 COVID-19 outbreaks and 300 379 outbreak-associated cases to CDPH. The most outbreaks (47.8%) and outbreak-associated cases (54.8%) occurred in the health care and social assistance sector, where outbreak incidence levels were highest in skilled nursing facilities and residential care facilities (1306 and 544 outbreaks per 1000 establishments, respectively). High proportions of outbreaks also occurred in the retail trade (8.6%) and manufacturing (7.9%) sectors. Demographics of outbreak-associated cases varied across industries. Conclusions. Certain California industries, particularly in the health care, manufacturing, and retail sectors, have experienced a high burden of COVID-19 outbreaks during the pandemic. Public Health Implications. Tracking COVID-19 outbreaks by industry may help target prevention efforts, including workforce vaccination. (Am J Public Health. 2022;112(8):1180-1190. https://doi.org/10.2105/AJPH.2022.306862).

Rapid Assessment and Containment of Candida auris Transmission in Postacute Care Settings-Orange County, California, 2019.

BACKGROUND: Candida auris, a multidrug-resistant yeast, can spread rapidly in ventilator-capable skilled-nursing facilities (vSNFs) and long-term acute care hospitals (LTACHs). In 2018, a laboratory serving LTACHs in southern California began identifying species of Candida that were detected in urine specimens to enhance surveillance of C auris, and C auris was identified in February 2019 in a patient in an Orange County (OC), California, LTACH. Further investigation identified C auris at 3 associated facilities. OBJECTIVE: To assess the prevalence of C auris and infection prevention and control (IPC) practices in LTACHs and vSNFs in OC. DESIGN: Point prevalence surveys (PPSs), postdischarge testing for C auris detection, and assessments of IPC were done from March to October 2019. SETTING: All LTACHs (n = 3) and vSNFs (n = 14) serving adult patients in OC. PARTICIPANTS: Current or recent patients in LTACHs and vSNFs in OC. INTERVENTION: In facilities where C auris was detected, PPSs were repeated every 2 weeks. Ongoing IPC support was provided. MEASUREMENTS: Antifungal susceptibility testing and whole-genome sequencing to assess isolate relatedness. RESULTS: Initial PPSs at 17 facilities identified 44 additional patients with C auris in 3 (100%) LTACHs and 6 (43%) vSNFs, with the first bloodstream infection reported in May 2019. By October 2019, a total of 182 patients with C auris were identified by serial PPSs and discharge testing. Of 81 isolates that were sequenced, all were clade III and highly related. Assessments of IPC identified gaps in hand hygiene, transmission-based precautions, and environmental cleaning. The outbreak was contained to 2 facilities by October 2019. LIMITATION: Acute care hospitals were not assessed, and IPC improvements over time could not be rigorously evaluated. CONCLUSION: Enhanced laboratory surveillance and prompt investigation with IPC support enabled swift identification and containment of C auris. PRIMARY FUNDING SOURCE: Centers for Disease Control and Prevention.

Burden of Candidemia in the United States, 2017.

BACKGROUND: Candidemia is a common healthcare-associated bloodstream infection with high morbidity and mortality. There are no current estimates of candidemia burden in the United States (US). METHODS: In 2017, the Centers for Disease Control and Prevention conducted active population-based surveillance for candidemia through the Emerging Infections Program in 45 counties in 9 states encompassing approximately 17 million persons (5% of the national population). Laboratories serving the catchment area population reported all blood cultures with Candida, and a standard case definition was applied to identify cases that occurred in surveillance area residents. Burden of cases and mortality were estimated by extrapolating surveillance area cases to national numbers using 2017 national census data. RESULTS: We identified 1226 candidemia cases across 9 surveillance sites in 2017. Based on this, we estimated that 22 660 (95% confidence interval [CI], 20 210-25 110) cases of candidemia occurred in the US in 2017. Overall estimated incidence was 7.0 cases per 100 000 persons, with highest rates in adults aged ≥ 65 years (20.1/100 000), males (7.9/100 000), and those of black race (12.3/100 000). An estimated 3380 (95% CI, 1318-5442) deaths occurred within 7 days of a positive Candida blood culture, and 5628 (95% CI, 2465-8791) deaths occurred during the hospitalization with candidemia. CONCLUSIONS: Our analysis highlights the substantial burden of candidemia in the US. Because candidemia is only one form of invasive candidiasis, the true burden of invasive infections due to Candida is higher. Ongoing surveillance can support future burden estimates and help assess the impact of prevention interventions.

Transmission of COVID-19 to Health Care Personnel During Exposures to a Hospitalized Patient - Solano County, California, February 2020.

On February 26, 2020, the first U.S. case of community-acquired coronavirus disease 2019 (COVID-19) was confirmed in a patient hospitalized in Solano County, California (1). The patient was initially evaluated at hospital A on February 15; at that time, COVID-19 was not suspected, as the patient denied travel or contact with symptomatic persons. During a 4-day hospitalization, the patient was managed with standard precautions and underwent multiple aerosol-generating procedures (AGPs), including nebulizer treatments, bilevel positive airway pressure (BiPAP) ventilation, endotracheal intubation, and bronchoscopy. Several days after the patient's transfer to hospital B, a real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) test for SARS-CoV-2 returned positive. Among 121 hospital A health care personnel (HCP) who were exposed to the patient, 43 (35.5%) developed symptoms during the 14 days after exposure and were tested for SARS-CoV-2; three had positive test results and were among the first known cases of probable occupational transmission of SARS-CoV-2 to HCP in the United States. Little is known about specific risk factors for SARS-CoV-2 transmission in health care settings. To better characterize and compare exposures among HCP who did and did not develop COVID-19, standardized interviews were conducted with 37 hospital A HCP who were tested for SARS-CoV-2, including the three who had positive test results. Performing physical examinations and exposure to the patient during nebulizer treatments were more common among HCP with laboratory-confirmed COVID-19 than among those without COVID-19; HCP with COVID-19 also had exposures of longer duration to the patient. Because transmission-based precautions were not in use, no HCP wore personal protective equipment (PPE) recommended for COVID-19 patient care during contact with the index patient. Health care facilities should emphasize early recognition and isolation of patients with possible COVID-19 and use of recommended PPE to minimize unprotected, high-risk HCP exposures and protect the health care workforce.

Outbreak of Norovirus Illness Among Wildfire Evacuation Shelter Populations - Butte and Glenn Counties, California, November 2018.

The Camp Fire, California's deadliest wildfire, began November 8, 2018, and was extinguished November 25 (1). Approximately 1,100 evacuees from the fire sought emergency shelter. On November 10, acute gastroenteritis (AGE) was reported in two evacuation shelters; norovirus illness was suspected, because it is commonly detected in shelter-associated AGE outbreaks. Norovirus is highly contagious and resistant to several disinfectants. Butte County Public Health Department (BCPHD), assisted by the California Department of Public Health (CDPH), initiated active surveillance to identify cases, confirm the etiology, and assess shelter infection prevention and control (IPC) practices to guide recommendations. During November 8-30, a total of 292 patients with AGE were identified among nine evacuation shelters; norovirus was detected in 16 of 17 unique patient stool specimens. Shelter IPC assessments revealed gaps in illness surveillance, isolation practices, cleaning, disinfection, and handwashing. CDPH and BCPHD collaborated with partner agencies to implement AGE screening, institute isolation protocols and 24-hour cleaning services, and promote proper hand hygiene. During disasters with limited resources, damaged infrastructure, and involvement of multiple organizations, establishing shelter disease surveillance and IPC is difficult. However, prioritizing effective surveillance and IPC at shelter activation is necessary to prevent, identify, and contain outbreaks.

Carbapenem and Cephalosporin Resistance among Enterobacteriaceae in Healthcare-Associated Infections, California, USA1.

We analyzed antimicrobial susceptibility test results reported in healthcare-associated infections by California hospitals during 2014-2017. Approximately 3.2% of Enterobacteriaceae reported in healthcare-associated infections were resistant to carbapenems and 26.9% were resistant to cephalosporins. The proportion of cephalosporin-resistant Escherichia coli increased 7% (risk ratio 1.07, 95% CI 1.04-1.11) per year during 2014-2017.

Vital Signs: Epidemiology and Recent Trends in Methicillin-Resistant and in Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections - United States.

INTRODUCTION: Staphylococcus aureus is one of the most common pathogens in health care facilities and in the community, and can cause invasive infections, sepsis, and death. Despite progress in preventing methicillin-resistant S. aureus (MRSA) infections in health care settings, assessment of the problem in both health care and community settings is needed. Further, the epidemiology of methicillin-susceptible S. aureus (MSSA) infections is not well described at the national level. METHODS: Data from the Emerging Infections Program (EIP) MRSA population surveillance (2005-2016) and from the Premier and Cerner Electronic Health Record databases (2012-2017) were analyzed to describe trends in incidence of hospital-onset and community-onset MRSA and MSSA bloodstream infections and to estimate the overall incidence of S. aureus bloodstream infections in the United States and associated in-hospital mortality. RESULTS: In 2017, an estimated 119,247 S. aureus bloodstream infections with 19,832 associated deaths occurred. During 2005-2012 rates of hospital-onset MRSA bloodstream infection decreased by 17.1% annually, but the decline slowed during 2013-2016. Community-onset MRSA declined less markedly (6.9% annually during 2005-2016), mostly related to declines in health care-associated infections. Hospital-onset MSSA has not significantly changed (p = 0.11), and community-onset MSSA infections have slightly increased (3.9% per year, p<0.0001) from 2012 to 2017. CONCLUSIONS AND IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: Despite reductions in incidence of MRSA bloodstream infections since 2005, S. aureus infections account for significant morbidity and mortality in the United States. To reduce the incidence of these infections further, health care facilities should take steps to fully implement CDC recommendations for prevention of device- and procedure-associated infections and for interruption of transmission. New and novel prevention strategies are also needed.

Carbapenem-Resistant Enterobacteriaceae Detection Practices in California: What Are We Missing?

Background: The Clinical and Laboratory Standards Institute (CLSI) revised the carbapenem breakpoints for Enterobacteriaceae in 2010. The number of hospitals that adopted revised breakpoints and the clinical impact of delayed adoption has not been explored. Methods: We performed a cross-sectional, voluntary survey of microbiology laboratories from California acute care hospitals and long-term acute care hospitals (LTAC) to determine use of revised CLSI breakpoints. Carbapenem-resistant Enterobacteriaceae (CRE) clinical isolates from a single tertiary-care hospital from 2013 to 2017 were examined. All isolates with an elevated minimum inhibitory concentration (MIC; ≥2 µg/mL) to imipenem or meropenem were tested for the presence of carbapenemase genes by polymerase chain reaction (PCR). Results: We received responses from 128 laboratories that serve 264/393 (67%) of hospitals and LTACs. Current CLSI carbapenem breakpoints for Enterobacteriaceae were used by 92/128 (72%) laboratories. Among laboratories that used current breakpoints, time to implementation varied from 0 to 68 months (mean, 41 months; median, 55 months). Application of historical breakpoints to isolates with a carbapenemase gene detected by PCR resulted in susceptibility rates of 8.9%, 18.6%, and 18.6% to ertapenem, imipenem, and meropenem, respectively. By current breakpoints, <1% of these isolates were susceptible to ertapenem or imipenem and 2.6% to meropenem. Conclusion: Clinicians and epidemiologists should be aware that use of outdated MIC breakpoints for Enterobacteriaceae remains common and can result in reports of false susceptibility to carbapenems and missed identification of carbapenemase producers. This misclassification could have consequences for patient care and infection control efforts to address carbapenemase-producing Enterobacteriaceae.

Hemodialyzer Reuse and Gram-Negative Bloodstream Infections.

BACKGROUND: Clusters of bloodstream infections caused by Burkholderia cepacia and Stenotrophomonas maltophilia are uncommon, but have been previously identified in hemodialysis centers that reprocessed dialyzers for reuse on patients. We investigated an outbreak of bloodstream infections caused by B cepacia and S maltophilia among hemodialysis patients in clinics of a dialysis organization. STUDY DESIGN: Outbreak investigation, including matched case-control study. SETTING & PARTICIPANTS: Hemodialysis patients treated in multiple outpatient clinics owned by a dialysis organization. PREDICTORS: Main predictors were dialyzer reuse, dialyzer model, and dialyzer reprocessing practice. OUTCOMES: Case patients had a bloodstream infection caused by B cepacia or S maltophilia; controls were patients without infection dialyzed at the same clinic on the same day as a case; results of environmental cultures and organism typing. RESULTS: 17 cases (9 B cepacia and 8 S maltophilia bloodstream infections) occurred in 5 clinics owned by the same dialysis organization. Case patients were more likely to have received hemodialysis with a dialyzer that had been used more than 6 times (matched OR, 7.03; 95% CI, 1.38-69.76) and to have been dialyzed with a specific reusable dialyzer (Model R) with sealed ends (OR, 22.87; 95% CI, 4.49-∞). No major lapses during dialyzer reprocessing were identified that could explain the outbreak. B cepacia was isolated from samples collected from a dialyzer header-cleaning machine from a clinic with cases and was indistinguishable from a patient isolate collected from the same clinic, by pulsed-field gel electrophoresis. Gram-negative bacteria were isolated from 2 reused Model R dialyzers that had undergone the facility's reprocessing procedure. LIMITATIONS: Limited statistical power and overmatching; few patient isolates and dialyzers available for testing. CONCLUSIONS: This outbreak was likely caused by contamination during reprocessing of reused dialyzers. Results of this and previous investigations demonstrate that exposing patients to reused dialyzers increases the risk for bloodstream infections. To reduce infection risk, providers should consider implementing single dialyzer use whenever possible.

Approaches to Modifying the Behavior of Clinicians Who Are Noncompliant With Antimicrobial Stewardship Program Guidelines.

Antimicrobial stewardship programs (ASPs) are a key national initiative to promote appropriate use of antibiotics and to reduce the burden of resistance. The dilemma of managing the outlier physician is especially complex. We outline strategies to establish a successful ASP that reviews appropriate efforts to achieve the goal of modifying outlier physicians' behavior. One must try to differentiate deviation from ASP norms from all other issues of outliers. Essential elements include identifying and understanding the local problems, planning, and achieving hospital administration and medical staff support. A successful ASP includes effective communication and acceptance of evidence-based recommendations, so that patient clinical outcomes will be optimized.

High colonization rate and prolonged shedding of Clostridium difficile in pediatric oncology patients.

Surveillance testing for Clostridium difficile among pediatric oncology patients identified stool colonization in 29% of patients without gastrointestinal symptoms and in 55% of patients with prior C. difficile infection (CDI). A high prevalence of C. difficile colonization and diarrhea complicates the diagnosis of CDI in this population.

Healthcare personnel with laboratory-confirmed mpox in California during the 2022 outbreak.

The California Department of Public Health (CDPH) reviewed 109 cases of healthcare personnel (HCP) with laboratory-confirmed mpox to understand transmission risk in healthcare settings. Overall, 90% of HCP with mpox had nonoccupational exposure risk factors. One occupationally acquired case was associated with sharps injury while unroofing a patient's lesion for diagnostic testing.

Association of the coronavirus disease 2019 (COVID-19) pandemic with the incidence of healthcare-associated infections in California hospitals.

OBJECTIVE: To assess the impact of the coronavirus disease 2019 (COVID-19) pandemic on the incidence of central-line-associated bloodstream infections (CLABSIs), Clostridioides difficile infections (CDIs), and methicillin-resistant Staphyloccocus aureus (MRSA) bloodstream infections (BSIs) in California acute-care hospitals. DESIGN: Retrospective cohort and before-and-after study. METHODS: We compared standardized infection ratios (SIRs) for CLABSI, CDI, and MRSA BSI from the second half of 2020 to the second half of 2019. We performed interrupted time-series (ITS) analyses for these infections to assess departures from long-term trends. We also examined the association between the proportion of facility beds that were occupied by COVID-19 patients in May and June of 2020 and the incidence of infections using negative binomial models. In addition, we compared standardized antimicrobial administration ratios (SAARs) for the second halves of 2019 and 2020. RESULTS: We detected substantial and significant increases in the SIRs for CLABSI and MRSA BSI from 2019 to 2020. For the ITS analysis, CLABSI and had significant positive values for the pandemic onset level-change parameters, and CLABSI and MRSA BSI had significant positive values for the postinterruption slope-change parameters. We also detected a positive association between facility COVID-19 patient occupancy and CLABSI and MRSA BSI incidence. We did not detect associations with the onset of the pandemic or COVID-19 patient occupancy and CDI. The SAAR for all antibacterial drugs decreased slightly, but the SAAR for drugs with a high risk for CDI increased slightly. CONCLUSIONS: This study adds to a body of literature documenting increases in CLABSI and MRSA BSI incidence during the pandemic.

Resident racial and ethnic composition, neighborhood-level socioeconomic status, and COVID-19 infections in California SNFs.

BACKGROUND: In California, >29,000 residents in skilled nursing facility (SNFs) were diagnosed with novel coronavirus disease 2019 (COVID-19) between March 2020 and November 2020. Prior research suggests that SNFs serving racially and ethnically minoritized residents often have fewer resources and lower quality of care. We performed a cross-sectional analysis of COVID-19 incidence among residents in California SNFs, assessing the association of SNF-level racial and ethnic compositions and facility- and neighborhood-level (census tract- and county-level) indicators of socioeconomic status (SES). METHODS: SNFs were grouped based on racial and ethnic composition using data from the Centers for Medicare and Medicaid Services; categories included SNFs with ≥88% White residents, SNFs with ≥32% Black or Latinx residents, SNFs with ≥32% Asian residents, or SNFs not serving a high proportion of any racial and ethnic composition (mixed). SNF resident-level COVID-19 infection data were obtained from the National Healthcare Safety Network from May 25, 2020 to August 16, 2020. Multilevel mixed-effects negative binomial regressions were used to estimate incidence rate ratios (IRR) for confirmed COVID-19 infections among residents. RESULTS: Among 971 SNFs included in our sample, 119 (12.3%) had ≥88% White residents; 215 (22.1%) had ≥32% Black or Latinx residents; 78 (8.0%) had ≥32% Asian residents; and 559 (57.6%) were racially and ethnically mixed. After adjusting for confounders, SNFs with ≥32% Black or Latinx residents (IRR = 2.40 [95% CI = 1.56, 3.68]) and SNFs with mixed racial and ethnic composition (IRR = 2.12 [95% CI = 1.49, 3.03]) both had higher COVID-19 incidence rates than SNFs with ≥88% White residents. COVID-19 incidence rates were also found to be higher in SNFs with low SES neighborhoods compared to those in high SES neighborhoods. CONCLUSION: Public health personnel should consider SNF- and neighborhood-level factors when identifying facilities to prioritize for COVID-19 outbreak prevention and control.

Healthcare-associated infection reporting completeness and quality during the coronavirus disease 2019 (COVID-19) pandemic in California hospitals.

We examined markers of completeness in healthcare-associated infection (HAI) data reported by California hospitals to the National Healthcare Safety Network for each half of 2020 compared with 2019. There were indications of decreased data completeness for both halves of 2020. California 2020 HAI data should be interpreted with caution.

Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreak investigation in a hospital emergency department-California, December 2020-January 2021.

We describe a large outbreak of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) involving an acute-care hospital emergency department during December 2020 and January 2021, in which 27 healthcare personnel worked while infectious, resulting in multiple opportunities for SARS-CoV-2 transmission to patients and other healthcare personnel. We provide recommendations for improving infection prevention and control.

Development of a Broth Microdilution Method To Characterize Chlorhexidine MICs among Bacteria Collected from 2005 to 2019 at Three U.S. Sites.

Chlorhexidine bathing to prevent transmission of multidrug-resistant organisms has been adopted by many U.S. hospitals, but increasing chlorhexidine use has raised concerns about possible emergence of resistance. We sought to establish a broth microdilution method for determining chlorhexidine MICs and then used the method to evaluate chlorhexidine MICs for bacteria that can cause health care-associated infections. We adapted a broth microdilution method for determining chlorhexidine MICs, poured panels, established quality control ranges, and tested Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae complex isolates collected at three U.S. sites. Chlorhexidine MICs were determined for 535 isolates including 129 S. aureus, 156 E. coli, 142 K. pneumoniae, and 108 E. cloacae complex isolates. The respective MIC distributions for each species ranged from 1 to 8 mg/L (MIC50 = 2 mg/L and MIC90 = 4 mg/L), 1 to 64 mg/L (MIC50 = 2 mg/L and MIC90 = 4 mg/L), 4 to 64 mg/L (MIC50 = 16 mg/L and MIC90 = 32 mg/L), and 1 to >64 mg/L (MIC50 = 16 mg/L and MIC90 = 64 mg/L). We successfully adapted a broth microdilution procedure that several laboratories were able to use to determine the chlorhexidine MICs of bacterial isolates. This method could be used to investigate whether chlorhexidine MICs are increasing. IMPORTANCE Chlorhexidine bathing to prevent transmission of multidrug-resistant organisms and reduce health care-associated infections has been adopted by many hospitals. There is concern about the possible unintended consequences of using this agent widely. One possible unintended consequence is decreased susceptibility to chlorhexidine, but there are not readily available methods to perform this evaluation. We developed a method for chlorhexidine MIC testing that can be used to evaluate for possible unintended consequences.

Characterizing Clostridioides difficile infections and hospital exposures in California using surveillance and administrative data, 2014-2015.

OBJECTIVE: To evaluate a method to identify hospitals contributing to Clostridioides difficile infections (CDI) at subsequent hospitalizations. DESIGN: Retrospective cohort study. METHODS: We merged 2014-2015 National Healthcare Safety Network (NHSN) inpatient CDI laboratory-identified events with hospital patient discharge data. For patients with incident community-onset CDI (CO CDI), we identified immediately preceding admissions (within 12 weeks) unrelated to CDI at different (exposure) hospitals. We calculated an exposure rate, and we selected hospitals with the highest (90th-100th percentile) rates by hospital type and compared these rates with reported standardized infection ratios (SIR) for CDI. RESULTS: We successfully matched 44,691 of 58,842 NHSN CDI records (76.0%) with a hospital discharge record. Among 36,215 unique matched records, 5,234 (14.5%) had an admission not related to CDI within 12 weeks prior to an incident CO CDI event, and 1,574 of these admissions (30.1%) occurred in a different hospital. For 33 hospitals with an exposure ranking within the 90th-100th percentile, CDI SIRs for 22 (66.7%) were not significantly different; 3 (9.1%) were lower; and 8 (24.2%) were higher than the national baseline. Also, 12 (36.4%) had an SIR ≤1.0. CONCLUSIONS: The identification of high-ranked exposure hospitals presents an alternative to SIR for measuring the contribution of hospitals to the CDI burden across the continuum of care. Further exploration of the potential factors leading to high exposure rank, such as antibiotic use and infection control practices, is indicated and may inform CDI prevention outreach to healthcare facilities and provider networks in California and elsewhere.