Bimodal distribution pattern associated with the PCR cycle threshold (Ct) and implications in COVID-19 infections.

SARS-CoV-2 is notable for its extremely high level of viral replication in respiratory epithelial cells, relative to other cell types. This may partially explain the high transmissibility and rapid global dissemination observed during the COVID-19 pandemic. Polymerase chain reaction (PCR) cycle threshold (Ct) number has been widely used as a proxy for viral load based on the inverse relationship between Ct number and amplifiable genome copies present in a sample. We examined two PCR platforms (Centers for Disease Control and Prevention 2019-nCoV Real-time RT-PCR, Integrated DNA Technologies; and TaqPath COVID-19 multi-plex combination kit, ThermoFisher Scientific) for their performance characteristics and Ct distribution patterns based on results generated from 208,947 clinical samples obtained between October 2020 and September 2021. From 14,231 positive tests, Ct values ranged from 8 to 39 and displayed a pronounced bimodal distribution. The bimodal distribution persisted when stratified by gender, age, and time period of sample collection during which different viral variants circulated. This finding may be a result of heterogeneity in disease progression or host response to infection irrespective of age, gender, or viral variants. Quantification of respiratory mucosal viral load may provide additional insight into transmission and clinical indicators helpful for infection control.

Persistent bacteremia and psoas abscess caused by a lethal toxin-deficient Paeniclostridiumsordellii.

We present a case of persistent bacteremia and psoas abscess from Paeniclostridium sordellii without severe symptoms or the classically associated toxic shock syndrome. Further laboratory evaluation demonstrated that the Paeniclostridium sordellii isolate lacked the lethal toxin gene and there was no cytotoxicity to exposed Vero cells.

Identification of SARS-CoV-2 RNA in healthcare heating, ventilation, and air conditioning units.

Evidence continues to grow supporting the aerosol transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To assess the potential role of heating, ventilation, and air conditioning (HVAC) systems in airborne viral transmission, this study sought to determine the viral presence, if any, on air handling units in a healthcare setting where coronavirus disease 2019 (COVID-19) patients were being treated. The presence of SARS-CoV-2 RNA was detected in approximately 25% of samples taken from ten different locations in multiple air handlers. While samples were not evaluated for viral infectivity, the presence of viral RNA in air handlers raises the possibility that viral particles can enter and travel within the air handling system of a hospital, from room return air through high-efficiency MERV-15 filters and into supply air ducts. Although no known transmission events were determined to be associated with these specimens, the findings suggest the potential for HVAC systems to facilitate transfer of virions to locations remote from areas where infected persons reside. These results are important within and outside of healthcare settings and may present necessary guidance for building operators of facilities that are not equipped with high-efficiency filtration. Furthermore, the identification of SARS-CoV-2 in HVAC components indicates the potential utility as an indoor environmental surveillance location.

Unintended consequences of a reflex urine culture order set on appropriate antibiotic use.

We evaluated the impact of reflex urine culture screen results on antibiotic initiation. More patients with positive urine screen but negative culture received antibiotics than those with a negative screen (30.5 vs 7.1%). Urine screen results may inappropriately influence antibiotic initiation in patients with a low likelihood of infection.

Healthcare-associated urinary tract infections with onset post hospital discharge.

OBJECTIVE: Current surveillance for healthcare-associated (HA) urinary tract infection (UTI) is focused on catheter-associated infection with hospital onset (HO-CAUTI), yet this surveillance does not represent the full burden of HA-UTI to patients. Our objective was to measure the incidence of potentially HA, community-onset (CO) UTI in a retrospective cohort of hospitalized patients. DESIGN: Retrospective cohort study. SETTING: Academic, quaternary care, referral center. PATIENTS: Hospitalized adults at risk for HA-UTI from May 2009 to December 2011 were included. METHODS: Patients who did not experience a UTI during the index hospitalization were followed for 30 days post discharge to identify cases of potentially HA-CO UTI. RESULTS: We identified 3,273 patients at risk for potentially HA-CO UTI. The incidence of HA-CO UTI in the 30 days post discharge was 29.8 per 1,000 patients. Independent risk factors of HA-CO UTI included paraplegia or quadriplegia (adjusted odds ratio [aOR], 4.6; 95% confidence interval [CI], 1.2-18.0), indwelling catheter during index hospitalization (aOR, 1.5; 95% CI, 1.0-2.3), prior piperacillin-tazobactam prescription (aOR, 2.3; 95% CI, 1.1-4.5), prior penicillin class prescription (aOR, 1.7; 95% CI, 1.0-2.8), and private insurance (aOR, 0.6; 95% CI, 0.4-0.9). CONCLUSIONS: HA-CO UTI may be common within 30 days following hospital discharge. These data suggest that surveillance efforts may need to be expanded to capture the full burden to patients and better inform antibiotic prescribing decisions for patients with a history of hospitalization.

Invasive Methicillin-Resistant Staphylococcus aureus Infections Among Persons Who Inject Drugs - Six Sites, 2005-2016.

In the United States, age-adjusted opioid overdose death rates increased by >200% during 1999-2015, and heroin overdose death rates increased nearly 300% during 2011-2015 (1). During 2011-2013, the rate of heroin use within the past year among U.S. residents aged ≥12 years increased 62.5% overall and 114.3% among non-Hispanic whites, compared with 2002-2004 (2). Increases in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections related to increases in injection drug use have been recently highlighted (3,4); likewise, invasive bacterial infections, including endocarditis, osteomyelitis, and skin and soft tissue infections, have increased in areas where the opioid epidemic is expanding (5-7). To assess the effects of the opioid epidemic on invasive methicillin-resistant Staphylococcus aureus (MRSA) infections during 2005-2016, surveillance data from CDC's Emerging Infections Program (EIP) were analyzed (8). Persons who inject drugs were estimated to be 16.3 times more likely to develop invasive MRSA infections than others. The proportion of invasive MRSA cases that occurred among persons who inject drugs increased from 4.1% in 2011 to 9.2% in 2016. Infection types were frequently those associated with nonsterile injection drug use. Continued increases in nonsterile injection drug use are likely to result in increases in invasive MRSA infections, underscoring the importance of public health measures to curb the opioid epidemic.

New Delhi metallo-ß-lactamase-1 (NDM-1) Escherichia coli isolated from household vacuum cleaner-Oregon, 2013.

The first Oregon case of New Delhi metallo-ß-lactamase-1 (NDM-1)-producing Escherichia coli was reported during November 2013. Epidemiologic investigation revealed only local outpatient medical care and no travel outside Oregon for both the patient and his household contact. Environmental sampling discovered a matching isolate from the patient's household vacuum cleaner, suggesting environmental persistence.

Evaluating Healthcare Claims for Neurocysticercosis by Using All-Payer All-Claims Data, Oregon, 2010-2013.

To characterize the frequency of neurocysticercosis, associated diagnostic codes, and place of infection, we searched Oregon's All Payer All-Claims dataset for 2010-2013. Twice as many cases were found by searching inpatient and outpatient data than by inpatient data alone. Studies relying exclusively on inpatient data underestimate frequency and miss less severe disease.

Predictive value of testing nasopharyngeal samples for respiratory viruses in the setting of lower respiratory tract disease.

To determine the predictive value of nasopharyngeal (NP) sample testing for respiratory viruses (RVs) in suspected lower respiratory tract disease, 72 paired NP and bronchoalveolar lavage (BAL) fluid specimen sets, mostly from transplant recipients or patients with hematologic malignancies, were analyzed. Overall, 31.3% of the specimens tested positive for an RV. In 19 sets (26.4%), the NP and BAL fluid specimens were both positive for an RV; in 3 sets (4.2%), the NP specimens were positive but the BAL fluid specimens were negative; and in 3 other sets, the NP specimens were negative but the BAL fluid specimens were positive. The positive and negative predictive values of the NP specimens were 86.4% and 94%, respectively.

Establishment of a statewide network for carbapenem-resistant enterobacteriaceae prevention in a low-incidence region.

OBJECTIVE: To establish a statewide network to detect, control, and prevent the spread of carbapenem-resistant Enterobacteriaceae (CRE) in a region with a low incidence of CRE infection. DESIGN: Implementation of the Drug Resistant Organism Prevention and Coordinated Regional Epidemiology (DROP-CRE) Network. SETTING AND PARTICIPANTS: Oregon infection prevention and microbiology laboratory personnel, including 48 microbiology laboratories, 62 acute care facilities, and 140 long-term care facilities. METHODS: The DROP-CRE working group, comprising representatives from academic institutions and public health, convened an interdisciplinary advisory committee to assist with planning and implementation of CRE epidemiology and control efforts. The working group established a statewide CRE definition and surveillance plan; increased the state laboratory capacity to perform the modified Hodge test and polymerase chain reaction for carbapenemases in real time; and administered surveys that assessed the needs and capabilities of Oregon infection prevention and laboratory personnel. Results of these inquiries informed CRE education and the response plan. RESULTS: Of 60 CRE reported from November 2010 through April 2013, only 3 were identified as carbapenemase producers; the cases were not linked, and no secondary transmission was found. Microbiology laboratories, acute care facilities, and long-term care facilities reported lacking carbapenemase testing capability, reliable interfacility communication, and CRE awareness, respectively. Survey findings informed the creation of the Oregon CRE Toolkit, a state-specific CRE guide booklet. CONCLUSIONS: A regional epidemiology surveillance and response network has been implemented in Oregon in advance of widespread CRE transmission. Prospective surveillance will determine whether this collaborative approach will be successful at forestalling the emergence of this important healthcare-associated pathogen.

Trends in invasive methicillin-resistant Staphylococcus aureus infections.

OBJECTIVE: To describe trends in the incidence of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children during 2005-2010. METHODS: We evaluated reports of invasive MRSA infections in pediatric patients identified from population-based surveillance during 2005-2010. Cases were defined as isolation of MRSA from a normally sterile site and classified on the basis of the setting of the positive culture and presence or absence of health care exposures. Estimated annual changes in incidence were determined by using regression models. National age- and race-specific incidences for 2010 were estimated by using US census data. RESULTS: A total of 876 pediatric cases were reported; 340 (39%) were among infants. Overall, 35% of cases were hospital-onset, 23% were health care-associated community-onset, and 42% were community-associated (CA). The incidence of invasive CA-MRSA infection per 100000 children increased from 1.1 in 2005 to 1.7 in 2010 (modeled yearly increase: 10.2%; 95% confidence interval: 2.7%-18.2%). No significant trends were observed for health care-associated community-onset and hospital-onset cases. Nationally, estimated invasive MRSA incidence in 2010 was higher among infants aged <90 days compared with older infants and children (43.9 vs 2.0 per 100000) and among black children compared with other races (6.7 vs 1.6 per 100000). CONCLUSIONS: Invasive MRSA infection in children disproportionately affects young infants and black children. In contrast to reports of declining incidence among adults, there were no significant reductions in health care-associated MRSA infections in children. Concurrently, the incidence of CA-MRSA infections has increased, underscoring the need for defining optimal strategies to prevent MRSA infections among children with and without health care exposures.

Clinical management of septic arthritis.

Septic arthritis is a rheumatologic emergency as joint destruction occurs rapidly and can lead to significant morbidity and mortality. Accurate diagnosis can be particularly challenging in patients with underlying inflammatory joint disease. This review outlines the risk factors for septic arthritis and summarizes the causative bacterial organisms. We highlight advances in antibiotic management with a focus on new drugs for methicillin-resistant Staphylococcus aureus (MRSA) and discuss the use of adjunctive therapies for treatment of septic arthritis in adults.

Use of electronic health record data to identify skin and soft tissue infections in primary care settings: a validation study.

BACKGROUND: Epidemiologic studies of skin and soft tissue infections (SSTIs) depend upon accurate case identification. Our objective was to evaluate the positive predictive value (PPV) of electronic medical record data for identification of SSTIs in a primary care setting. METHODS: A validation study was conducted among primary care outpatients in an academic healthcare system. Encounters during four non-consecutive months in 2010 were included if any of the following were present in the electronic health record: International Classification of Diseases, Ninth Revision (ICD-9) code for an SSTI, Current Procedural Terminology (CPT) code for incision and drainage, or a positive wound culture. Detailed chart review was performed to establish presence and type of SSTI. PPVs and 95% confidence intervals (CI) were calculated among all encounters, initial encounters, and cellulitis/abscess cases. RESULTS: Of the 731 encounters included, 514 (70.3%) were initial encounters and 448 (61.3%) were cellulitis/abscess cases. When the presence of an ICD-9 code, CPT code, or positive culture was used to identify SSTIs, 617 encounters were true positives, yielding a PPV of 84.4% [95% CI: 81.8-87.0%]. The PPV for using ICD-9 codes alone to identify SSTIs was 90.7% [95 % CI: 88.5-92.9%]. For encounters with cellulitis/abscess codes, the PPV was 91.5% [95% CI: 88.9-94.1%]. CONCLUSIONS: ICD-9 codes may be used to retrospectively identify SSTIs with a high PPV. Broadening SSTI case identification with microbiology data and CPT codes attenuates the PPV. Further work is needed to estimate the sensitivity of this method.

Comparison of antibiograms developed for inpatients and primary care outpatients.

To support antimicrobial stewardship, some healthcare systems have begun creating outpatient antibiograms. We developed inpatient and primary care outpatient antibiograms for a regional health maintenance organization (HMO) and academic healthcare system (AHS). Antimicrobial susceptibilities from 16,428 Enterococcus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa cultures from 2010 were summarized and compared. Methicillin susceptibility among S. aureus was similar in inpatients and primary care outpatients (HMO: 61.2% versus 61.9%, P = 0.951; AHS: 62.9% versus 63.3%, P > 0.999). E. coli susceptibility to trimethoprim/sulfamethoxazole was also similar (HMO: 81.8% versus 83.6%, P = 0.328; AHS: 77.2% versus 80.9%, P = 0.192), but ciprofloxacin susceptibility differed (HMO: 88.9% versus 94.6%, P < 0.001; AHS: 81.2% versus 90.6%, P < 0.001). In the HMO, ciprofloxacin-susceptible P. aeruginosa were more frequent in primary care outpatients than in inpatients (91.4% versus 79.0%, P = 0.007). Comparison of cumulative susceptibilities across settings yielded no consistent patterns; therefore, outpatient primary care antibiograms may more accurately inform prudent empiric antibiotic prescribing.

Neurocysticercosis among resettled refugees from Burma.

Taenia solium is the most common helminthic infection of the central nervous system and a leading cause of epilepsy in developing nations. Little is known about neurocysticercosis in refugees from Southeast Asia which is endemic for T solium. We present two cases in a single household of refugees from Burma.

Seroprevalence of antibodies against Taenia solium cysticerci among refugees resettled in United States.

Neurocysticercosis (NCC) is a disease caused by central nervous system infection by the larval stage of the pork tapeworm, Taenia solium. In developing countries, NCC is a leading cause of adult-onset epilepsy. Case reports of NCC are increasing among refugees resettled to the United States and other nations, but the underlying prevalence among refugee groups is unknown. We tested stored serum samples from the Centers for Disease Control and Prevention Migrant Serum Bank for antibodies against T. solium cysts by using the enzyme-linked immunoelectrotransfer blot. Seroprevalence was high among all 4 populations tested: refugees from Burma (23.2%), Lao People's Democratic Republic (18.3%), Bhutan (22.8%), and Burundi (25.8%). Clinicians caring for refugee populations should suspect NCC in patients with seizure, chronic headache, or unexplained neurologic manifestations. Improved understanding of the prevalence of epilepsy and other associated diseases among refugees could guide recommendations for their evaluation and treatment before, during, and after resettlement.

Health care-associated invasive MRSA infections, 2005-2008.

CONTEXT: Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of public health importance; MRSA prevention programs that may affect MRSA transmission and infection are increasingly common in health care settings. Whether there have been changes in MRSA infection incidence as these programs become established is unknown; however, recent data have shown that rates of MRSA bloodstream infections (BSIs) in intensive care units are decreasing. OBJECTIVE: To describe changes in rates of invasive health care-associated MRSA infections from 2005 through 2008 among residents of 9 US metropolitan areas. DESIGN, SETTING, AND PARTICIPANTS: Active, population-based surveillance for invasive MRSA in 9 metropolitan areas covering a population of approximately 15 million persons. All reports of laboratory-identified episodes of invasive (from a normally sterile body site) MRSA infections from 2005 through 2008 were evaluated and classified based on the setting of the positive culture and the presence or absence of health care exposures. Health care-associated infections (ie, hospital-onset and health care-associated community-onset), which made up 82% of the total infections, were included in this analysis. MAIN OUTCOME MEASURES: Change in incidence of invasive health care-associated MRSA infections and health care-associated MRSA BSIs using population of the catchment area as the denominator. RESULTS: From 2005 through 2008, there were 21,503 episodes of invasive MRSA infection; 17,508 were health care associated. Of these, 15,458 were MRSA BSIs. The incidence rate of hospital-onset invasive MRSA infections was 1.02 per 10,000 population in 2005 and decreased 9.4% per year (95% confidence interval [CI], 14.7% to 3.8%; P = .005), and the incidence of health care-associated community-onset infections was 2.20 per 10,000 population in 2005 and decreased 5.7% per year (95% CI, 9.7% to 1.6%; P = .01). The decrease was most prominent for the subset of infections with BSIs (hospital-onset: -11.2%; 95% CI -15.9% to -6.3%; health care-associated community-onset: -6.6%; 95% CI -9.5% to -3.7%). CONCLUSION: Over the 4-year period from 2005 through 2008 in 9 diverse metropolitan areas, rates of invasive health care-associated MRSA infections decreased among patients with health care-associated infections that began in the community and also decreased among those with hospital-onset invasive disease.

Reactive arthritis after enteric infections in the United States: the problem of definition.

Bacterial enteric infections cause substantial morbidity in the United States both from acute illness and sequelae that follow. Reactive arthritis (ReA) is a poorly defined term that is used to describe a variety of rheumatologic phenomena that may occur after Salmonella, Shigella, Campylobacter, and Yersinia infection, as well as other types of infections (eg, Chlamydia). This review focuses on clinical and epidemiologic investigations of ReA following bacterial enteric infection in the United States. Only 2 population-based studies of ReA following enteric infection have been performed in the United States. ReA following outbreaks of Campylobacter and Yersinia infection has not been studied, and investigations following Shigella and Salmonella outbreaks have focused primarily on the more narrowly defined, but now outdated, concept of "Reiter's syndrome" rather than ReA. Additional epidemiologic studies are needed to determine the burden of illness due to ReA following enteric infection, but a clearer definition of the term is a prerequisite.

Evaluating the potential public health impact of a Staphylococcus aureus vaccine through use of population-based surveillance for invasive methicillin-resistant S. aureus disease in the United States.

We evaluated the potential effects of a hypothetical vaccine in preventing invasive methicillin-resistant Staphylococcus aureus (MRSA) disease in the United States. Using an active, population-based surveillance program, we estimated baseline disease rates in the United States and compared three distinct vaccination strategies which targeted adults > or =65 years of age, persons at risk for recurrent invasive infection, and patients at hospital discharge. The strategies were projected to reduce the burden of invasive MRSA disease by 12.1%, 13.9% and 17.6%, respectively; with the strategy of vaccinating both adults > or =65 years of age and all adults at hospital discharge having the greatest impact per dose. Our data suggest that availability of an effective S. aureus vaccine could result in substantial reductions in invasive MRSA disease incidence. As candidate vaccines are evaluated, these data will be important in determining the optimal vaccination strategy.