Evolution of blaKPC Under the Pressure of Carbapenems and Ceftazidime/Avibactam in a Patient With Persistent Bacteremia Caused by Klebsiella pneumoniae.

A 30-year-old Korean man with myelodysplastic syndrome admitted hospital due to undifferentiated fever and recurrent skin lesions. He received combination therapy with high doses of meropenem, tigecycline and amikacin, yielding carbapenem resistant Klebsiella pneumoniae (CRKP) harboring K. pneumoniae carbapenemase (KPC)-2 from blood cultures on hospital day (HD) 23. Ceftazidime/avibactam was started at HD 37 and CRKP was eradicated from blood cultures after 5 days. However, ceftazidime/avibactam-resistant CRKP carrying KPC-44 emerged after 26 days of ceftazidime/avibactam treatment and then ceftazidime/avibactam-resistant, carbapenem-susceptible K. pneumoniae carrying KPC-135 was isolated on HD 65. The 3-D homology of KPC protein showed that hot spot changes in the omega loop could be attributed to ceftazidime/avibactam resistance and loss of carbapenem resistance. Whole genome sequencing of serial isolates supported that phenotypic variation was due to clonal evolution than clonal replacement. The treatment regimen was changed from CAZ/AVI to meropenem-based therapy (meropenem 1 g iv q 8 hours and amikacin 600 mg iv per day) starting with HD 72. CAZ/AVI-susceptible CRKP was presented again from blood cultures on HD 84, and the patient expired on HD 85. This is the first Korean report on the acquisition of ceftazidime/avibactam resistance through the emergence of blaKPC variants.

Clinical evaluation of the T2Candida assay for the rapid diagnosis of candidemia.

We evaluated the clinical performance of the T2Candida assay. The overall agreement of the T2Candida assay results with the blood culture results was 95.3 % (121/127). The T2Candida assay detected three Candida albicans/tropicalis-positive specimens and one Candida krusei/glabrata-positive specimen; however, it did not detect two Candida glabrata specimens.

Severe Human Parainfluenza Virus Community- and Healthcare-Acquired Pneumonia in Adults at Tertiary Hospital, Seoul, South Korea, 2010-2019.

The characteristics of severe human parainfluenza virus (HPIV)-associated pneumonia in adults have not been well evaluated. We investigated epidemiologic and clinical characteristics of 143 patients with severe HPIV-associated pneumonia during 2010-2019. HPIV was the most common cause (25.2%) of severe virus-associated hospital-acquired pneumonia and the third most common cause (15.7%) of severe virus-associated community-acquired pneumonia. Hematologic malignancy (35.0%), diabetes mellitus (23.8%), and structural lung disease (21.0%) were common underlying conditions. Co-infections occurred in 54.5% of patients admitted to an intensive care unit. The 90-day mortality rate for HPIV-associated pneumonia was comparable to that for severe influenza virus-associated pneumonia (55.2% vs. 48.4%; p = 0.22). Ribavirin treatment was not associated with lower mortality rates. Fungal co-infections were associated with 82.4% of deaths. Clinicians should consider the possibility of pathogenic co-infections in patients with HPIV-associated pneumonia. Contact precautions and environmental cleaning are crucial to prevent HPIV transmission in hospital settings.

Pitfalls of a Multiplex PCR Panel for Identification of Bloodstream Pathogens.

BACKGROUND: We evaluated the diagnostic performance of the FilmArray Blood Culture Identification Panel (BCID; bioMerieux) for the detection of bloodstream pathogens. METHODS: From May to August 2022, up to 67 samples from positive blood cultures previously processed with BACTEC FX (BD) were collected and submitted to the BCID panel. BCID panel results were compared with traditional culture results. RESULTS: We tested 67 positive blood culture samples; 13 samples were from pediatric bottles of BACTEC Peds Plus/F media (BD). The overall sensitivity of the BCID panel was 89.9% (62/69; 95% CI, 80.2 - 95.3%). For blood-stream pathogens targeted by the BCID panel, sensitivity was 98.4% (62/63; 95% CI, 90.7 - > 99.9%). Interestingly, Proteus species were additionally detected in 6 samples from pediatric blood culture bottles. CONCLUSIONS: BCID demonstrated high clinical sensitivity for target pathogens, but positive findings for unexpected multiple targets or Proteus species require cautious interpretation to avoid false positives.

Phylogenetic lineage dynamics of global parainfluenza virus type 3 post-COVID-19 pandemic.

During the coronavirus disease 2019 (COVID-19) pandemic, outbreaks of parainfluenza virus type 3 (PIV-3) decreased due to infection control measures. However, a post-pandemic resurgence of PIV-3 has recently been observed. Nonetheless, the role of viral genetic epidemiology, possibly influenced by a genetic bottleneck effect, remains unexplored. We investigated the phylogenetic structure of the publicly available PIV-3 whole-genome and hemagglutinin-neuraminidase (HN) gene sequences spanning the last 65 years, including the COVID-19 pandemic. Sequences were retrieved from the nucleotide database of the National Center for Biotechnology Information using the search term "Human respirovirus 3." Sequence subsets covering all six genes of PIV-3 or the HN gene were designated as the whole-genome and HN surveillance data sets, respectively. Using these data sets, we constructed maximum-likelihood phylogenetic trees and performed a time-scaled analysis using a Bayesian SkyGrid coalescent prior. A total of 455 whole-genome and 1,139 HN gene sequences were extracted, revealing 10 and 11 distinct lineages, respectively, with >98% concurrence in lineage assignments. During the 2020 COVID-19 pandemic, only three single-lineage clusters were identified in Japan, Korea, and the USA. The inferred year of origin for PIV-3 was 1938 (1903-1963) for the whole-genome data set and 1955 (1930-1963) for the HN gene data set. Our study suggests that PIV-3 epidemics in the post-COVID era are likely influenced by a pandemic-driven bottleneck phenomenon and supports previous hypotheses suggesting s that PIV-3 originated during the early half of the 20th century.IMPORTANCEUsing publicly available parainfluenza virus type 3 (PIV-3) whole-genome sequences, we estimated that PIV-3 originated during the 1930s, consistent with previous hypotheses. Lineage typing and time-scaled phylogenetic analysis revealed that PIV-3 experienced a bottleneck phenomenon in Korea and the USA during the coronavirus disease 2019 pandemic. We identified the conservative hemagglutinin-neuraminidase gene as a viable alternative marker in long-term epidemiological studies of PIV-3 when whole-genome analysis is limited.

Comparative Analysis of CT Findings and Clinical Outcomes in Adult Patients With Disseminated and Localized Pulmonary Nocardiosis.

BACKGROUND: Pulmonary nocardiosis is a rare opportunistic infection with occasional systemic dissemination. This study aimed to investigate the computed tomography (CT) findings and prognosis of pulmonary nocardiosis associated with dissemination. METHODS: We conducted a retrospective analysis of patients diagnosed with pulmonary nocardiosis between March 2001 and September 2023. We reviewed the chest CT findings and categorized them based on the dominant CT findings as consolidation, nodules and/or masses, consolidation with multiple nodules, and nodular bronchiectasis. We compared chest CT findings between localized and disseminated pulmonary nocardiosis and identified significant prognostic factors associated with 12-month mortality using multivariate Cox regression analysis. RESULTS: Pulmonary nocardiosis was diagnosed in 75 patients, of whom 14 (18.7%) had dissemination, including involvement of the brain in 9 (64.3%) cases, soft tissue in 3 (21.4%) cases and positive blood cultures in 3 (21.4%) cases. Disseminated pulmonary nocardiosis showed a higher frequency of cavitation (64.3% vs. 32.8%, P = 0.029) and pleural effusion (64.3% vs. 29.5%, P = 0.014) compared to localized infection. The 12-month mortality rate was 25.3%. The presence of dissemination was not a significant prognostic factor (hazard ratio [HR], 0.80; confidence interval [CI], 0.23-2.75; P = 0.724). Malignancy (HR, 9.73; CI, 2.32-40.72; P = 0.002), use of steroid medication (HR, 3.72; CI, 1.33-10.38; P = 0.012), and a CT pattern of consolidation with multiple nodules (HR, 4.99; CI, 1.41-17.70; P = 0.013) were associated with higher mortality rates. CONCLUSION: Pulmonary nocardiosis with dissemination showed more frequent cavitation and pleural effusion compared to cases without dissemination, but dissemination alone did not affect the mortality rate of pulmonary nocardiosis.

Changing Epidemiology of Clinical Isolates of Candida Species during the Coronavirus Disease 2019 Pandemic: Data Analysis from a Korean Tertiary Care Hospital for 6 Years (2017-2022).

This study assessed the changes in Candida species distribution and antifungal susceptibility patterns during the coronavirus disease 2019 (COVID-19) pandemic compared with a pre-pandemic period in Korea. We retrospectively investigated the specimen, species type, and antifungal susceptibility of Candida isolates obtained between 2016 and 2022. Data between two periods were compared: 2016-2019 (pre-pandemic) and 2020-2022 (pandemic). We included 11,396 clinical isolates of Candida species (5137 isolates in the pre-pandemic and 6259 isolates in the pandemic). The most prevalent species was Candida albicans (50.4%), followed by Candida glabrata (22.7%), Candida tropicalis (12.5%), and Candida parapsilosis complex (12.5%). Their ranks were unchanged; however, their relative isolation ratios varied during the pandemic, exhibiting differences ranging from 0.4 to 2.5 across species. The incidence of candidemia increased during the pandemic (average 1.79 episodes per 10,000 patient days) compared with pre-pandemic levels (average 1.45 episodes per 10,000 patient days) in both intensive-care-unit (ICU) and non-ICU patients. Additionally, C. parapsilosis complex candidemia increased by 1.6-fold during the pandemic. During the pandemic, C. albicans and C. tropicalis candidemia significantly increased by 1.5- and 1.4-fold in ICU patients. In contrast, C. parapsilosis complex candidemia surged 2.1-fold in non-ICU patients. These species exhibited reduced resistance to fluconazole, voriconazole, caspofungin, and micafungin in the pandemic compared with the pre-pandemic. This study underscores the heightened incidence of Candida-related infections during the COVID-19 pandemic and emphasizes the importance of ongoing surveillance of Candida species epidemiology beyond the pandemic's scope.

Prevention of Cytomegalovirus Infection in Solid Organ Transplant Recipients: Guidelines by the Korean Society of Infectious Diseases and the Korean Society for Transplantation.

Cytomegalovirus (CMV) is the most important opportunistic viral pathogen in solid organ transplant (SOT) recipients. The Korean guideline for the prevention of CMV infection in SOT recipients was developed jointly by the Korean Society for Infectious Diseases and the Korean Society of Transplantation. CMV serostatus of both donors and recipients should be screened before transplantation to best assess the risk of CMV infection after SOT. Seronegative recipients receiving organs from seropositive donors face the highest risk, followed by seropositive recipients. Either antiviral prophylaxis or preemptive therapy can be used to prevent CMV infection. While both strategies have been demonstrated to prevent CMV infection post-transplant, each has its own advantages and disadvantages. CMV serostatus, transplant organ, other risk factors, and practical issues should be considered for the selection of preventive measures. There is no universal viral load threshold to guide treatment in preemptive therapy. Each institution should define and validate its own threshold. Valganciclovir is the favored agent for both prophylaxis and preemptive therapy. The evaluation of CMV-specific cell-mediated immunity and the monitoring of viral load kinetics are gaining interest, but there was insufficient evidence to issue recommendations. Specific considerations on pediatric transplant recipients are included.

Validation of a new risk stratification system-based management for methicillin-resistant Staphylococcus aureus bacteraemia: analysis of a multicentre prospective study.

PURPOSE: Distinguishing between complicated and uncomplicated Staphylococcus aureus bacteraemia (SAB) is therapeutically essential. However, this distinction has limitations in reflecting the heterogeneity of SAB and encouraging targeted diagnostics. Recently, a new risk stratification system for SAB metastatic infection, involving stepwise approaches to diagnosis and treatment, has been suggested. We assessed its applicability in methicillin-resistant SAB (MRSAB) patients. METHODS: We retrospectively analysed data of a 3-year multicentre, prospective cohort of hospitalised patients with MRSAB. We classified the patients into three risk groups: low, indeterminate, and high, based on the new system and compared between-group management and outcomes. RESULTS: Of 380 patients with MRSAB, 6.3% were classified as low-, 7.6% as indeterminate-, and 86.1% as high-risk for metastatic infection. No metastatic infection occurred in the low-, 6.9% in the indeterminate-, and 19.6% in the high-risk groups (P < 0.001). After an in-depth diagnostic work-up, patients were finally diagnosed as 'without metastatic infection (6.3%)', 'with metastatic infection (17.4%)', and 'uncertain for metastatic infection (76.3%)'. 30-day mortality increased as the severity of diagnosis shifted from 'without metastatic infection' to 'uncertain for metastatic infection' and 'with metastatic infection' (P = 0.09). In multivariable analysis, independent factors associated with metastatic complications were suspicion of endocarditis in transthoracic echocardiography, clinical signs of metastatic infection, Pitt bacteraemia score ≥ 4, and persistent bacteraemia. CONCLUSIONS: The new risk stratification system shows promise in predicting metastatic complications and guiding work-up and management of MRSAB. However, reducing the number of cases labelled as 'high-risk' and 'uncertain for metastatic infection' remains an area for improvement.

Safety and outcome of treatment of latent tuberculosis infection in liver transplant recipients.

PURPOSE: Liver transplant (LT) recipients have an increased risk of tuberculosis (TB), which is associated with higher mortality rates. This retrospective cohort study assessed the outcome and tolerability of screening and treatment of latent tuberculosis infection (LTBI) in LT recipients. METHODS: Between March 2020 and February 2022, all adult LT candidates at our institution were screened for LTBI. The candidates who tested positive for interferon-γ-releasing assay or met epidemiological or clinical-radiological criteria for LTBI were treated and monitored. RESULTS: Among the 857 LT recipients, 199 (23.2%) were diagnosed with LTBI, of which 171 (85.9%) initiated LTBI treatment. The median duration of follow-up was 677 days. Adequate LTBI treatment occurred in 141/171 (82.5%) patients and was discontinued prematurely in 30/171 (17.5%) patients. The most common reason for discontinuation was liver enzyme elevation (11/30, 36.7%), although only five discontinued treatment due to suspicion of isoniazid-associated hepatotoxicity. None of the LTBI-treated patients developed active TB during the follow-up period, while 3.6% (1/28) of untreated LTBI patients and 0.6% (4/658) of patients without LTBI developed TB. CONCLUSION: These findings demonstrate that LTBI screening and treatment is a safe and effective strategy to prevent TB in LT recipients. However, monitoring for adverse events and liver enzyme elevation is recommended.

Clinical safety of remdesivir therapy in COVID-19 patients with renal insufficiency.

Though remdesivir benefits COVID-19 patients, its use in those with renal dysfunction is currently limited due to concerns about possible toxic effects of accumulated sulfobutylether-ß-cyclodextrin (SBECD) on liver and kidney. We examined renal and hepatic function for a month in renally-impaired COVID-19 patients who were treated or not treated with remdesivir to assess the safety of the drug. A retrospective study was performed in adult COVID-19 patients with glomerular filtration rates of <30 ml/min/1.73 m2 at admission to a tertiary care hospital between November 2020 and March 2022. Data on serum creatinine and liver chemistry were collected serially. A total of 101 patients with impaired renal function were analyzed, comprising 64 remdesivir-treated patients and 37 who did not receive any antiviral agent. Although remdesivir-treated patients were more likely to be infected with the Omicron variant (79.7% vs. 48.6%), baseline characteristics did not differ significantly between the two groups. Among patients who initially did not require dialysis, 18.4% (7/38) of remdesivir-treated patients developed acute kidney injury (AKI) at days 4-6, compared with 51.7% (15/29) of non-remdesivir-treated patients. Liver injury severity worsened in 3.1% (2/64) of remdesivir-treated patients and 5.4% (2/37) of non-remdesivir-treated patients at days 4-6. In addition, there was no significant increase in AKI and liver injury over time in remdesivir-treated patients, and there were no cases of discontinuation of remdesivir due to adverse reactions. Concerns regarding the safety of SBECD should not lead to hasty withholding of remdesivir treatment in renally-impaired COVID-19 patients.

Evaluating amikacin minimum inhibitory concentration in trailing growth for Mycobacterium avium complex.

BACKGROUND: Amikacin is a first-line drug that must be evaluated when performing an antimycobacterial susceptibility test (AST) for Mycobacterium avium complex (MAC). However, the presence of sporadic trailing growth in MAC makes determining the precise point for reading its minimal inhibitory concentration (MIC) challenging. METHODS: Susceptibility was re-tested for 134 MAC clinical isolates using the Sensititre SLOMYCOI panel, the rrs gene was sequenced, and amikacin exposure history was investigated. The MIC50, MIC90, and the epidemiological cut-off value (ECOFF) were calculated using the EUCAST method. RESULTS: After re-testing and ignoring trailing growth, of the 22 M. intracellulare isolates originally classified as resistant to amikacin according to the CLSI guideline, 10 strains were reclassified as intermediate and four as susceptible. Similarly, from the seven resistant M. avium strains, one was reclassified as intermediate and four as susceptible. No rrs gene mutations were detected in any isolates, including resistant strains. When ignoring trailing growth, the calculated MIC50, MIC90, and ECOFF values closely aligned with the EUCAST MIC distribution. CONCLUSION: To maintain the current CLSI breakpoint, trailing growth should be ignored when reading the amikacin MIC of MAC. To read the MIC at complete bacterial inhibition, the CLSI breakpoint needs to be raised.

Routine ophthalmologic examination in Klebsiella pneumoniae bacteremia is not necessary: incidence of and risk factors for ocular involvement.

Klebsiella pneumoniae bacteremia is known to present a virulent clinical course, including multiple metastatic infections, which is not uncommon in Asia. However, there are limited data on the incidence and risk factors for ocular involvement in K. pneumoniae bacteremia. We retrospectively reviewed the medical records of all patients with K. pneumoniae bacteremia who underwent ophthalmologic examination in a tertiary center in Seoul, Korea, from February 2012 to December 2020. Two retinal specialists reviewed the findings of the ophthalmologic examinations and classified them as endophthalmitis, chorioretinitis, and no ocular involvement. Of 689 patients, 56 [8.1%; 95% confidence interval (CI) 6.2-10.4] had ocular involvement, and 9 (1.3%; 95% CI 0.6-2.5) were diagnosed with endophthalmitis. Of 47 patients with chorioretinitis, 45 (95.7%) improved with systemic antibiotic therapy alone. Community-onset bacteremia (100% vs 62.1% vs 57.4%, P = 0.04), cryptogenic liver abscess (55.6% vs 11.8% vs 8.5%, P = 0.003), and metastatic infection (66.7% vs 5.8% vs 10.6%, P < 0.001) were more common in endophthalmitis than in no ocular involvement or chorioretinitis. In the multivariable analysis, cryptogenic liver abscess [adjusted odds ratio (aOR), 6.63; 95% CI 1.44-35.20] and metastatic infection (aOR, 17.52; 95% CI 3.69-96.93) were independent risk factors for endophthalmitis. Endophthalmitis was not associated with 30-day mortality. Endophthalmitis is rare in Asian patients with K. pneumoniae bacteremia. Targeted ophthalmologic examination in those with cryptogenic liver abscess, metastatic infection, or ocular symptoms may be more appropriate than routine examination of all patients.

False positive Aspergillus galactomannan assay results caused by specific parenteral nutrition.

In September 2022, the proportion of clinically false positive results with high index values for the galactomannan (GM) assay increased dramatically in our hospital and remained high until November 2022. We aimed to identify the possible causative agent that led to the dramatic increase in false positivity in GM assay. A case-control-control study was conducted, and patients admitted to two intensive care units between September and November 2022 were included. We defined each time point at which the GM assay was conducted in a patient as an episode and classified episodes into strong-positive (≥10.0 index; case), positive (control), and negative (<0.5 index; control) groups. We compared the medications administered in three groups and measured GM levels in relevant medications, including parenteral nutrition (PN). In total, 118 episodes in 33 patients were classified into three groups. There were 46 negative, 23 positive, and 49 strong-positive episodes, and there was a significant difference in the use of Winuf® PNs (P < .001) between the three groups. Forty episodes (82%) in the strong-positive group received Winuf®, compared with three (6.5%) in the negative group and one (4.3%) in the positive group (P < .001). All samples of Winuf® PNs used in the five patients whose GM results were repeatedly strong-positive were strongly positive for GM. False positivity in GM assay can be caused by the administration of specific PNs. A thorough investigation of prescribed medications should be considered when there is an abrupt increase in the proportion of strong-positive or positive GM results.

Clinical Characteristics of and Risk Factors for Subsequent Carbapenemase-producing Enterobacterales (CPE) Bacteraemia in Rectal CPE Carriers.

BACKGROUND: Due to high mortality and limited treatment options, the rise in carbapenemase-producing Enterobacterales (CPE) has become a major concern. This study aimed to evaluate the incidence and characteristics of subsequent CPE bacteraemia in rectal CPE carriers and investigate the risk factors for CPE bacteraemia compared with non-carbapenemase-producing (non-CP) Enterobacterales bacteraemia. METHODS: A retrospective analysis was conducted on adult patients who were confirmed to have CPE colonisation by stool surveillance culture at a tertiary hospital from January 2018 to February 2022. All episodes of Enterobacterales bacteraemia up to 6 months after CPE colonisation were identified. RESULTS: Of 1174 patients identified as rectal CPE carriers, 69 (5.8%; 95% CI 4.6-7.3%) experienced subsequent CPE bacteraemia during the 6 months after the diagnosis of CPE colonisation. Colonisation by a Klebsiella pneumoniae carbapenemase (KPC) producer (or CP-K. pneumoniae), colonisation by multiple CPE species, chronic kidney disease and haematological malignancy were independently associated with CPE bacteraemia in CPE carriers. When CPE carriers developed Enterobacterales bacteraemia, the causative agent was more frequently non-CP Enterobacterales than CPE (63.6% vs. 36.4%). Among these patients, colonisation with a KPC producer, CPE colonisation at multiple sites, shorter duration from colonisation to bacteraemia (< 30 days) and recent intraabdominal surgery were independent risk factors for CPE bacteraemia rather than non-CP Enterobacterales bacteraemia. CONCLUSIONS: In CPE carriers, non-CP Enterobacterales were more often responsible for bacteraemia than CPE. Empirical antibiotic therapy for CPE should be considered when sepsis is suspected in a CPE carrier with risk factors for CPE bacteraemia.

Prevention of human milk-acquired cytomegalovirus infection in very-low-birth-weight infants.

BACKGROUND: The aim of the study was to determine the rate of cytomegalovirus virolactia in the human milk (HM) of mothers of VLBW infants, compare the CMV infection rates and the changes in CMV DNA viral load and nutrient profile among different HM preparation methods. METHODS: A prospective randomized controlled study was performed in infants with gestational age < 32 weeks or birth-weight < 1500 g admitted to neonatal intensive care unit of Asan Medical Center and Haeundae Paik Hospital who were given mother's own milk. Enrolled infants were randomized into three groups according to the HM preparation methods: freezing-thawing (FT), FT + low-temperature Holder pasteurization (FT + LP), and FT + high-temperature short-term pasteurization (FT + HP). Urine CMV culture and PCR were obtained at birth and at 4, 8, and 12 weeks. HM CMV culture and PCR were obtained at birth and at 3, 6, 9, and 12 weeks. Changes in macronutrients in HM was obtained at 4 ~ 6 weeks. RESULTS: Of 564 infants, 217 mothers (38.5%) produced CMV PCR positive milk. After exclusion, a total of 125 infants were randomized into the FT (n = 41), FT + LP (n = 42), and FT + HP (n = 42) groups, whose rate of HM-acquired CMV infection was 4.9% (n = 2), 9.5% (n = 4), and 2.4% (n = 1), respectively. Out of seven CMV infected infants, two infants fed with FT + LP HM developed CMV infection- associated symptoms. Ages at diagnoses were earlier (28.5 days after birth) and at younger post conceptional age (< 32 weeks) in comparison to infants with asymptomatic CMV infection. CMV DNA viral load significantly decreased after pasturizations, especially in FT + HP group. CONCLUSIONS: HM-acquired symptomatic CMV infection rate is low and its impact on clinical course was not serious in our VLBW infants. However, evidences showing poor neurodevelopmental outcome in later life, we need to generate a guideline to protect VLBW infant form HM transmitted CMV infection. Based on our small sized study, we did not find any superiority in pasteurizing HM with frequently used LP in comparison to frozen or HP HM. More research is needed to determine the method and duration of pasteurization to reduce the HM-acquired CMV infection.

Epidemiology and Characteristics of Respiratory Syncytial Virus Pneumonia in Critically Ill Adults.

Background: Severe respiratory syncytial virus (RSV)-associated pneumonia in adults has rarely been addressed. We investigated the burden and clinical characteristics of severe RSV-associated pneumonia in critically ill adult patients. Methods: We analyzed a prospective cohort of 2865 adults with severe pneumonia who were admitted to the intensive care unit in a 2700-bed tertiary care hospital from 2010 to 2019. The epidemiology, characteristics, and outcomes of 92 cases of severe RSV-associated pneumonia and 163 cases of severe influenza virus (IFV)-associated pneumonia were compared. Results: Of 1589 cases of severe community-acquired pneumonia, the incidence of RSV-associated pneumonia was less than half that of IFV-associated pneumonia (3.4% vs 8.1%). However, among 1276 cases of severe hospital-acquired pneumonia (HAP), there were slightly more cases of RSV-associated than IFV-associated pneumonia (3.8% vs 3.5%). During the 9 epidemic seasons, RSV-A (5 seasons) and RSV-B (4 seasons) predominated alternately. Structural lung disease, diabetes mellitus, and malignancy were common underlying diseases in both groups. Immunocompromise (57.6% vs 34.4%; P < .001) and hospital acquisition (47.8% vs 23.9%; P < .001) were significantly more common in the RSV group. Coinfection with Streptococcus pneumoniae (3.3% vs 9.8%; P = .08) and methicillin-susceptible Staphylococcus aureus (1.1% vs 6.8%; P = .06) tended to be less frequent in the RSV group. The 90-day mortality was high in both groups (39.1% vs 40.5%; P = .89). Conclusions: RSV infection was associated with substantial morbidity and mortality in critically ill adult patients, similar to IFV. The relatively higher incidence of RSV in severe HAP suggests that the transmissibility of RSV can exceed that of IFV in a hospital setting.

Culture-Negative Fusobacterium nucleatum Brain Abscess and Pleural Empyema Cases Revealed by 16S rRNA Sequencing.

BACKGROUND: We reported two Fusobacterium nucleatum cases each of brain abscesses and pleural empyema, using 16S rRNA sequencing technology. METHODS: We reviewed clinical records and microbiological findings in four patients with F. nucleatum infection. RESULTS: All conventional culture results from peripheral blood, cerebrospinal fluid, and pleural fluid samples were found to be negative for this pathogen. Three patients were treated with antimicrobial agents for more than a week before specimen sampling. All patients recovered from their fusobacterial infections and were discharged. CONCLUSIONS: Molecular identification methods such as 16S rRNA sequencing should accompany conventional culture to detect obligate anaerobic bacteria in deep-seated sites and organs.

Prospective Evaluation of SARS-CoV-2 Rapid Antigen Test for Screening of Asymptomatic Caregivers.

BACKGROUND: This study aimed to assess clinical performance of a rapid antigen test (RAT) for screening asymptomatic patients during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron outbreak. METHODS: RAT with the routine real-time reverse transcription-polymerase chain reaction (rRT-PCR) using the same nasopharyngeal swab in universal transport medium was performed for rapid screening of asymptomatic caregivers of emergent patients from March to April 2022 in a tertiary-care hospital in Korea. Clinical performance of RAT compared to that analyzed by rRT-PCR was evaluated. RESULTS: A total of 900 caregivers were enrolled in this study, of which 14 (1.6%) were RAT-positive and 44 (5.0%) were positive for rRT-PCR. Overall sensitivity and specificity of RAT were 31.8% and 100.0%, respectively. CONCLUSIONS: Caution must be taken when using RAT as a screening test for asymptomatic caregivers as this may lead to outbreaks among high-risk patients.