Epidemiology of carbapenem-resistant organisms in Alameda County, California, 2019-2021

Objective

Carbapenem-resistant organisms (CROs) are an urgent health threat. Since 2017, Alameda County Health Public Health Department (ACPHD) mandates reporting of carbapenem-resistant Enterobacterales (CRE) and encourages voluntary reporting of non-CRE CROs including carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenem-resistant Pseudomonas aeruginosa (CRPA). Surveillance data from ACPHD were analyzed to describe the epidemiology of CROs and target public health interventions.

Methods

Healthcare facilities in Alameda County reported CRO cases and submitted isolates to ACPHD to characterize carbapenemase genes; deaths were identified via the California Electronic Death Registration System. CRO cases with isolates resistant to one or more carbapenems were analyzed from surveillance data from July 2019 to June 2021.

Results

Four hundred and forty-two cases of CROs were reported to Alameda County from 408 patients. The county case rate for CROs was 29 cases per 100,000 population, and cases significantly increased over the 2-year period. CRPA was most commonly reported (157 cases, 36%), and cases of CRAB increased 1.83-fold. One-hundred eighty-six (42%) cases were identified among residents of long-term care facilities; 152 (37%) patients had died by January 2022. One hundred and seven (24%) cases produced carbapenemases.

Conclusions

The high burden of CROs in Alameda County highlights the need for continued partnership on reporting, testing, and infection prevention to limit the spread of resistant organisms. A large proportion of cases were identified in vulnerable long-term care residents, and CRAB was an emerging CRO among this population. Screening for CROs and surveillance at the local level are important to understand epidemiology and implement public health interventions.

Epidemiology of Culture-Negative Pulmonary Tuberculosis-Alameda County, 2010-2019

CONTEXT

Patients with culture-negative pulmonary TB (PTB) can face delays in diagnosis that worsen outcomes and lead to ongoing transmission. An understanding of current trends and characteristics of culture-negative PTB can support earlier detection and access to care.

OBJECTIVE

Describe epidemiology of culture-negative PTB.

DESIGN, SETTING, PARTICIPANTS

We utilized Alameda County TB surveillance data from 2010 to 2019. Culture-negative PTB cases met clinical but not laboratory criteria for PTB per US National Tuberculosis Surveillance System definitions. We calculated trends in annual incidence and proportion of culture-negative PTB using Poisson and weighted linear regression, respectively. We further compared demographic and clinical characteristics among culture-negative versus culture-positive PTB cases.

RESULTS

During 2010-2019, there were 870 cases of PTB, of which 152 (17%) were culture-negative. The incidence of culture-negative PTB declined by 76%, from 1.9/100 000 to 0.46/100 000 ( P for trend <.01), while the incidence of culture-positive PTB reduced by 37% (6.5/100 000 to 4.1/100 000, P for trend =.1). Culture-negative PTB case-patients were more likely than culture-positive PTB case-patients to be younger (7.9% were children <15 years old vs 1.1%; P < .01), recent immigrants within 5 years of arrival (38.2% vs 25.5%; P < .01), and have a TB contact (11.2% vs 2.9%; P < .01). Culture-negative PTB case-patients were less likely than culture-positive PTB case-patients to be evaluated because of TB symptoms (57.2% vs 74.7%; P < .01) or have cavitation on chest imaging (13.1% vs 38.8%; P < .01). At the same time culture-negative PTB case-patients were less likely to die during TB treatment (2.0% vs 9.6%; P < .01).

CONCLUSIONS

The incidence of culture-negative PTB disproportionately declined compared with culture-positive TB and raises concern for gaps in detection. Expansion of screening programs for recent immigrants and TB contacts and greater recognition of risk factors may increase detection of culture-negative PTB.

1455. Diagnosis and Testing of Travel-Associated Dengue, Alameda County, California – 2019

Background

Dengue is an acute febrile infection with one of the four dengue viruses that are transmitted through the bite of mosquitoes. It is a communicable disease reportable to local health departments under Title 17 of the California Code of Regulations via CalREDIE (California Reportable Disease Information Exchange), which receives positive Electronic Lab Reports or Confidential Morbidity Report forms when Dengue infection is strongly suspected. Alameda County is among the top 5 jurisdictions in California for travel-associated Dengue infection reports. In order to inform best practices for diagnosis and treatment, we explored Dengue reports to Alameda County pre-pandemic.

Methods

CalREDIE data for possible Dengue infections from 2019 were categorized according to CSTE’s Dengue Virus Infections 2015 Surveillance Case Definition into cases (probable and confirmed) or non-cases (suspect and not a case). Univariate and bivariate analysis were conducted in R.

Results

In 2019, 83 reports of possible Dengue infections were received; 23 met the case classification criteria for confirmed (n=8) or probable (n=15) cases. Most (61%) of the cases were reported between the months of June and October (Figure 1). All cases were symptomatic after travel to an area where Dengue is endemic, notably India (39%), Mexico (17%) and the Philippines (13%). Of the cases, 70% visited the Emergency Department and 48% were hospitalized due to concerns for severe dengue (Table 1). Cases had &gt; 4 times the odds of being hospitalized (Odds Ratio = 4.89, 95% Confidence Interval = 1.63-14.7, p = 0.01) compared to non-cases. 78% of the cases were tested for Dengue within 1 week from symptom onset, but of those, only 39% had a PCR or antigen test while 83% had an IgM test and 78% had an IgG test (Table 2). Figure 1Table 1:Patient Characteristics by CalREDIE Case Resolution Status of 2019 Dengue ReportsTable 2:Laboratory Testing Practices for 2019 Cases with Labs within 7 days of Symptom Onset

Conclusion

More outreach efforts are needed to educate health care providers on providing timely and adequate testing to travelers and improve diagnosis of travel-associated Dengue. Based on pre-pandemic surveillance in Alameda County, Dengue should be strongly suspected in patients who present with an acute febrile illness and history of travel to Dengue endemic areas such as India, Mexico, and the Philippines. Health care providers suspecting Dengue should test with either PCR or antigen tests within a week of symptom onset.

Disclosures

All Authors: No reported disclosures.

2038. Epidemiology of Carbapenem-Resistant Organisms in Alameda County, California (July 2019 - June 2021)

Background

Carbapenem-resistant Enterobacterales (CREs) and some Carbapenem-resistant organisms (CROs) are considered urgent threats by the CDC. Since 2017, the Alameda County Public Health Department has mandated the reporting of CRE and encouraged voluntary reporting of non-CRE CROs. Surveillance data from these cases were analyzed to describe the epidemiology of infections and to target local public health interventions.

Methods

Healthcare facilities in Alameda County reported cases of CROs to the public health department directly to staff or through Electronic Laboratory Reporting and submitted isolates to the public health laboratory for ascertainment of carbapenemase genes by whole genome sequencing on the Illumina MiSeq platform; deaths were recorded via the California Electronic Death Registration System. Surveillance data were analyzed for cases July 2019 – June 2021 identified by the clinical laboratory as resistant to one or more carbapenems.

Results

From July 2019 – June 2021, 444 cases of CROs were reported to Alameda County from 409 patients. The county case rate for CROs over the two-year period was 29 cases per 100,000 population. Of the reported cases, 218 (49%) were CRE species: Escherichia coli, Klebsiella spp., and Enterobacter spp. Of the remaining cases, 157 (35%) were carbapenem-resistant Pseudomonas aeruginosa, 46 (10%) were carbapenem-resistant Acinetobacter baumannii (CRAB), and 23 (5%) were other carbapenem-resistant species. Cases by carbapenemase status are described in Table 1. Of the cases, 192 (43%) were among residents of long-term care facilities or long-term acute care hospitals; 340 (77%) cases were identified in patients over &gt;50 years, and 168 (38%) cases have a death on record through January 2022. Among isolates with a carbapenemase gene (n = 129), KPC (32%) was the most commonly identified (Table 2).

Conclusion

The high burden of CROs in Alameda County highlights the need for continued partnership on reporting, testing and infection prevention measures to limit the spread of resistant organisms. A large proportion of cases were identified in vulnerable long-term care residents and 104 (24%) cases were identified as carbapenemase-producing, with a higher percentage among CRAB isolates, informing future targeted public health interventions.

Disclosures

All Authors: No reported disclosures.

Risk factors for third-generation cephalosporin-resistant and extended-spectrum β-lactamase-producing Escherichia coli carriage in domestic animals of semirural parishes east of Quito, Ecuador

Extended-spectrum β-lactamase (ESBL)-producing and other antimicrobial resistant (AR) Escherichia coli threaten human and animal health worldwide. This study examined risk factors for domestic animal colonization with ceftriaxone-resistant (CR) and ESBL-producing E. coli in semirural parishes east of Quito, Ecuador, where small-scale food animal production is common. Survey data regarding household characteristics, animal care, and antimicrobial use were collected from 304 households over three sampling cycles, and 1195 environmental animal fecal samples were assessed for E. coli presence and antimicrobial susceptibility. Multivariable regression analyses were used to assess potential risk factors for CR and ESBL-producing E. coli carriage. Overall, CR and ESBL-producing E. coli were detected in 56% and 10% of all fecal samples, respectively. The odds of CR E. coli carriage were greater among dogs at households that lived within a 5 km radius of more than 5 commercial food animal facilities (OR 1.72, 95% CI 1.15-2.58) and lower among dogs living at households that used antimicrobials for their animal(s) based on veterinary/pharmacy recommendation (OR 0.18, 95% CI 0.04-0.96). Increased odds of canine ESBL-producing E. coli carriage were associated with recent antimicrobial use in any household animal (OR 2.69, 95% CI 1.02-7.10) and purchase of antimicrobials from pet food stores (OR 6.83, 95% CI 1.32-35.35). Food animals at households that owned more than 3 species (OR 0.64, 95% CI 0.42-0.97), that used antimicrobials for growth promotion (OR 0.41, 95% CI 0.19-0.89), and that obtained antimicrobials from pet food stores (OR 0.47, 95% CI 0.25-0.89) had decreased odds of CR E. coli carriage, while food animals at households with more than 5 people (OR 2.22, 95% CI 1.23-3.99) and located within 1 km of a commercial food animal facility (OR 2.57, 95% CI 1.08-6.12) had increased odds of ESBL-producing E. coli carriage. Together, these results highlight the complexity of antimicrobial resistance among domestic animals in this setting.

Epidemiology of Coronavirus Disease 2019 at a County Jail-Alameda County, California, March 2020-March 2021

CONTEXT

Coronavirus disease 2019 (COVID-19) incidence rates are 2- to 5-fold higher among persons incarcerated in the United States than in the general population.

PROGRAM OR POLICY

We describe an outbreak investigation of COVID-19 at a jail (jail A) in Alameda County during March 2020-March 2021.

IMPLEMENTATION

To prevent COVID-19 cases among incarcerated persons and employees, staff at jail A and the county public health department worked to develop and recommend infection control measures implemented by jail A including, but not limited to, face covering use among incarcerated persons and staff; cohorting incarcerated persons at a higher risk of severe COVID-19 in dedicated housing units; quarantining all newly detained individuals for 14 days; and offering testing for all symptomatic incarcerated persons, newly incarcerated persons at day 2 and day 10, and all persons who resided in a housing unit where a COVID-19 case was detected.

EVALUATION

A total of 571 COVID-19 cases were detected among incarcerated persons at jail A during March 2020-March 2021, which represented a total incidence of 280 per 1000 population, 5 times higher than the rate in Alameda County. Of the 571 cases among incarcerated persons, 557 (98%) were male; 415 (73%) were aged 18 to 40 years; 249 (44%) were Latino; and 180 (32%) were African American; 354 (62%) were not symptomatic; and 220 (39%) had no comorbidities. Less than 2% of infected incarcerated persons were hospitalized, and no deaths were reported.

DISCUSSION

COVID-19 disproportionately impacted persons incarcerated at jail A, with higher numbers among Latinos and African Americans. Implementation of COVID-19 infection control and testing measures, and collaboration between public health, law enforcement, and health care providers may have, in part, led to reductions in morbidity and mortality associated with COVID-19 at jail A.

Social and Environmental Determinants of Community-Acquired Antimicrobial-Resistant Escherichia coli in Children Living in Semirural Communities of Quito, Ecuador

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL), a family of bacteria that includes Escherichia coli, have emerged as a global health threat. This study examined risks associated with carriage of third-generation cephalosporin-resistant (3GC-R) E. coli, including ESBL-producing, multidrug-resistant, and extensively drug-resistant (XDR) strains in children living in semirural parishes of Quito, Ecuador. We conducted a longitudinal study with two cycles of sampling (N = 374, N = 366) that included an analysis of child fecal samples and survey questions relating to water, sanitation, and hygiene, socioeconomic status, household crowding, and animal ownership. We used multivariate regression models to assess risk factors associated with a child being colonized. Across the two cycles, 18.4% (n = 516) of the 3GC-R isolates were ESBL-producing E. coli, and 40.3% (n = 516) were XDR E. coli. Children living in households that owned between 11 and 20 backyard animals had an increased odds of being colonized with XDR E. coli (odds ratio [OR] = 1.94, 95% confidence interval [CI]: 1.05-3.60) compared with those with no animals. Households that reported smelling odors from commercial poultry had increased odds of having a child positive for XDR E. coli (OR = 1.72, 95% CI: 1.11-2.66). Our results suggest that colonization of children with antimicrobial-resistant E. coli is influenced by exposure to backyard and commercial livestock and poultry. Future studies should consider community-level risk factors because child exposures to drug-resistant bacteria are likely influenced by neighborhood and regional risk factors.

Caretaker knowledge, attitudes, and practices (KAP) and carriage of extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) in children in Quito, Ecuador

Background

The rapid spread of extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) is an urgent global health threat. We examined child caretaker knowledge, attitudes, and practices (KAP) towards proper antimicrobial agent use and whether certain KAP were associated with ESBL-EC colonization of their children.

Methods

Child caretakers living in semi-rural neighborhoods in peri-urban Quito, Ecuador were visited and surveyed about their KAP towards antibiotics. Fecal samples from one child (less than 5 years of age) per household were collected at two time points between July 2018 and May 2019 and screened for ESBL-EC. A repeated measures analysis with logistic regression was used to assess the relationship between KAP levels and child colonization with ESBL-EC.

Results

We analyzed 740 stool samples from 444 children living in households representing a range of environmental conditions. Of 374 children who provided fecal samples at the first household visit, 44 children were colonized with ESBL-EC (11.8%) and 161 were colonized with multidrug-resistant E. coli (43%). The prevalences of ESBL-EC and multidrug-resistant E. coli were similar at the second visit (11.2% and 41.3%, respectively; N = 366). Only 8% of caretakers knew that antibiotics killed bacteria but not viruses, and over a third reported that they “always” give their children antibiotics when the child’s throat hurts (35%). Few associations were observed between KAP variables and ESBL-EC carriage among children. The odds of ESBL-EC carriage were 2.17 times greater (95% CI: 1.18–3.99) among children whose caregivers incorrectly stated that antibiotics do not kill bacteria compared to children whose caregivers correctly stated that antibiotics kill bacteria. Children from households where the caretaker answered the question “When your child’s throat hurts, do you give them antibiotics?” with “sometimes” had lower odds of ESBL-EC carriage than those with a caretaker response of “never” (OR 0.48, 95% CI 0.27–0.87).

Conclusion

Caregivers in our study population generally demonstrated low knowledge regarding appropriate use of antibiotics. Our findings suggest that misinformation about the types of infections (i.e. bacterial or viral) antibiotics should be used for may be associated with elevated odds of carriage of ESBL-EC. Understanding that using antibiotics is appropriate to treat infections some of the time may reduce the odds of ESBL-EC carriage. Overall, however, KAP measures of appropriate use of antibiotics were not strongly associated with ESBL-EC carriage. Other individual- and community-level environmental factors may overshadow the effect of KAP on ESBL-EC colonization. Intervention studies are needed to assess the true effect of improving KAP on laboratory-confirmed carriage of antimicrobial resistant bacteria, and should consider community-level studies for more effective management.

Abstract 518: Hypoxia and high interstitial pressure present within the tumor microenvironment can promote T cell suppression and exhaustion

Introduction: The tumor microenvironment is thought to be hostile to the optimal functionality of immune cells. In addition to hypoxia, tumors have a higher interstitial pressure than normal tissue. We examined the impact of hypoxia and increased pressure on human T cell function in vitro. We hypothesize that hypoxia and high pressure induced a more profound and durable exhaustion of activated T cells.

Methods: We cultivated human healthy PBMCs stimulated with phytohemagglutinin (PHA) or CD3/CD28 beads under tumor hypoxic conditions (1%O2, 2PSI) and compared it to normoxic in vitro culture conditions (20% O2, 0 PSI). We utilized the AVATAR system (Xcellbio), a novel bioreactor with highly customable cultivation conditions that allows for the modulation of oxygen and pressure. Functionality and phenotypic changes induced by different cultivation conditions were assessed by flow cytometry and cytokine release assays.

Results: Upon stimulation of PBMCs for 3 days, we observed that hypoxia markedly reduced IFNγ and TNFα cytokine release. Additionally, hypoxia induced an overall decrease in surface expression of the activation and metabolic markers CD71 (transferrin) and CD98 (neutral amino acids transporter), while promoting an increased expression of the inhibitory receptor PD1. This was true for both CD4+ and CD8+ T cells. Following this initial 3-day “priming” stimulation, cells spent 2-days in a “resting period” and underwent a second stimulation under a different condition (cells under normoxia were cultured under hypoxia and vice versa). We found that cells initially primed under hypoxic conditions maintained higher levels of PD1 expression after the second stimulation, regardless of whether the latter condition was normoxic or hypoxic.

Conclusions: Taken together these observations suggest that T cell priming in hypoxic and high pressure conditions present in tumors induce an irreversible state of T cell exhaustion and point out a dominant effect of hypoxia over normoxia. Our data suggest that environmental culture conditions greatly affect T cell responses and should be taken into account when studying T cell functionality, especially in the investigation of novel therapeutic agents targeting the immune system.

Citation Format: Chiara Rancan, Rachel Marusinec, James Lim, Lawrence Fong. Hypoxia and high interstitial pressure present within the tumor microenvironment can promote T cell suppression and exhaustion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 518.