Emergence and Persistent Dominance of SARS-CoV-2 Omicron BA.2.3.7 Variant, Taiwan.

Since April 2022, waves of SARS-CoV-2 Omicron variant cases have surfaced in Taiwan and spread throughout the island. Using high-throughput sequencing of the SARS-CoV-2 genome, we analyzed 2,405 PCR-positive swab samples from 2,339 persons and identified the Omicron BA.2.3.7 variant as a major lineage within recent community outbreaks in Taiwan.

Outbreak investigation in a COVID-19 designated hospital: The combination of phylogenetic analysis and field epidemiology study suggesting airborne transmission.

BACKGROUND: Healthcare-associated COVID-19 infections caused by SARS-CoV-2 have increased morbidity and mortality. Hospitals and skilled nursing facilities (SNFs) have been challenged by infection control and management. METHODS: This case study presents an outbreak investigation in a COVID-19-designated hospital and a hospital-based SNF. Real-time polymerase chain reaction (PCR) and other studies were performed on samples obtained from SNF residents, hospital patients, and healthcare workers (HCWs). The results of the laboratory tests and field epidemiological data were analyzed. Genome sequencing and phylogenetic analysis of SARS-CoV-2 were performed to identify the associations between cases. The tracer gas was released and recorded by a thermal imaging camera to investigate the spatial relations within clusters. RESULTS: During the outbreak, 29 COVID-19 infections in 3 clusters were identified through hospital-wide, risk-guided, and symptom-driven PCR tests. This included 12 HCWs, 5 patients, and 12 SNF residents who had been hospitalized for at least 14 days. Serology tests did not identify any cases among the PCR-negative individuals. The phylogenetic analysis revealed that viral strains from the 3 clusters shared a common mutation of G3994T and were phylogenetically related, which suggested that this outbreak had a common source rather than multiple introductions from the community. Linked cases exhibited vertical spatial distribution, and the sulfur hexafluoride release test confirmed a potential airborne transmission. CONCLUSIONS: This report addressed the advantage of a multi-disciplinary team in outbreak investigation. Identifying an airborne transmission within an outbreak highlighted the importance of regular maintenance of ventilation systems.

In vitro activity of cefiderocol, cefepime/enmetazobactam, cefepime/zidebactam, eravacycline, omadacycline, and other comparative agents against carbapenem-non-susceptible Pseudomonas aeruginosa and Acinetobacter baumannii isolates associated from bloodstream infection in Taiwan between 2018-2020.

BACKGROUND/PURPOSE: This study aimed to investigate the in vitro susceptibilities of carbapenem-non-susceptible Pseudomonas aeruginosa (CNSPA) and Acinetobacter baumannii (CNSAB) isolates to cefiderocol, novel ß-lactamase inhibitor (BLI) combinations, new tetracycline analogues, and other comparative antibiotics. METHODS: In total, 405 non-duplicate bacteremic CNSPA (n = 150) and CNSAB (n = 255) isolates were collected from 16 hospitals in Taiwan between 2018 and 2020. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method, and susceptibilities were interpreted according to the relevant guidelines or in accordance with results of previous studies and non-species-related pharmacokinetic/pharmacodynamic data. RESULTS: Among the isolates tested, cefiderocol demonstrated potent in vitro activity against CNSPA (MIC50/90, 0.25/1 mg/L; 100% of isolates were inhibited at ≤4 mg/L) and CNSAB (MIC50/90, 0.5/2 mg/L; 94.9% of isolates were inhibited at ≤4 mg/L) isolates. More than 80% of CNSPA isolates were susceptible to cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, and amikacin, based on breakpoints established by the Clinical and Laboratory Standards Institute. Activities of new BLI combinations varied significantly. Tetracycline analogues, including tigecycline (MIC50/90, 1/2 mg/L; 92.5% of CNSAB isolates were inhibited at ≤2 mg/L) and eravacycline (MIC50/90, 0.5/1 mg/L; 99.6% of CNSAB isolates were inhibited at ≤2 mg/L) exhibited more potent in vitro activity against CNSAB than omadacycline (MIC50/90, 4/8 mg/L). CONCLUSIONS: The spread of CNSPA and CNSAB poses a major challenge to global health. Significant resistance be developed even before a novel agent becomes commercially available. The development of on-site antimicrobial susceptibility tests for these novel agents is of great clinical importance.

Nationwide surveillance of antimicrobial resistance in invasive isolates of Streptococcus pneumoniae in Taiwan from 2017 to 2019.

BACKGROUND/PURPOSE: Streptococcus pneumoniae causes pneumonia and other invasive diseases, and is a leading cause of mortality in the elderly population. The present study aimed to provide current antimicrobial resistance and epidemiological profiles of S. pneumoniae infections in Taiwan. METHODS: A total of 252 nonduplicate S. pneumoniae isolates were collected from patients admitted to 16 hospitals in Taiwan between January 2017 and December 2019, and were analyzed. The minimum inhibitory concentration of antibiotics was determined using the Vitek 2 automated system for antimicrobial susceptibility testing. Furthermore, epidemiological profiles of S. pneumoniae infections were analyzed. RESULTS: Among the strains analyzed, 88% were recognized as invasive pneumococcal strains. According to the Clinical and Laboratory Standards Institute criteria for non-meningitis, the prevalence of penicillin-non-susceptible S. pneumoniae demonstrated a declining trend from 43.6% in 2017 to 17.2% in 2019. However, the rate of penicillin-non-susceptible S. pneumoniae was 85.7% based on the criteria for meningitis. Furthermore, the prevalence of ceftriaxone-non-susceptible S. pneumoniae was 62.7% based on the criteria for meningitis. Isolates demonstrated higher susceptibility toward doripenem and ertapenem than toward meropenem and imipenem. An increased rate of non-susceptibility toward levofloxacin was observed in southern Taiwan (15.1%) and elderly patients (≥65 years; 11.4%). Most isolates were susceptible to vancomycin and linezolid. CONCLUSION: Empirical treatment with ceftriaxone monotherapy for pneumococcal meningitis should be carefully monitored owing to its high non-susceptibility rate. The susceptibility rates of most isolates to penicillin (used for treating non-meningitis pneumococcal diseases), carbapenems (ertapenem and doripenem), respiratory quinolones (moxifloxacin and levofloxacin), vancomycin, and linezolid suggested the potential of these antibiotics in treating pneumococcal diseases in Taiwan.

National surveillance of antimicrobial susceptibilities to dalbavancin, telavancin, tedizolid, eravacycline, omadacycline and other comparator antibiotics and serotype distribution of invasive Streptococcus pneumoniae isolates in adults: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) programme in 2017-2020.

OBJECTIVES: The aim of this study was to investigate the trends in serotypes and in vitro antimicrobial susceptibility of Streptococcus pneumoniae causing adult invasive pneumococcal disease (IPD) to dalbavancin, telavancin, tedizolid, eravacycline, omadacycline and other comparator antibiotics from 2017-2020 following implementation of the 13-valent pneumococcal conjugate vaccine (PCV-13) and during the COVID-19 (coronavirus disease 2019) pandemic. METHODS: During the study period, 237 S. pneumoniae isolates were collected from non-duplicate patients, covering 15.0% of IPD cases in Taiwan. Antimicrobial susceptibility testing was performed using a Sensititre® system. A latex agglutination method (ImmuLex™ Pneumotest Kit) was used to determine serotypes. RESULTS: Susceptibility rates were high for vancomycin (100%), teicoplanin (100%) and linezolid (100%), followed by ceftaroline (non-meningitis) (98.3%), moxifloxacin (94.9%) and quinupristin/dalfopristin (89.9%). MIC50 and MIC90 values of dalbavancin, telavancin, tedizolid, eravacycline and omadacycline were generally low. Non-vaccine serotype 23A was the leading cause of IPD across the adult age range. Isolates of serotype 15B were slightly fewer than those of PCV-13 serotypes in patients aged ≥65 years. The overall case fatality rate was 15.2% (36/237) but was especially high for non-PCV-13 serotype 15B (21.4%; 3/14). Vaccine coverage was 44.7% for PCV-13 and 49.4% for the 23-valent pneumococcal polysaccharide vaccine (PPSV-23), but was 57% for both PCV-13 and PPSV-23. CONCLUSION: The incidence of IPD was stationary after PCV-13 introduction and only dramatically decreased in the COVID-19 pandemic in 2020. The MIC50 and MIC90 values of dalbavancin, telavancin, tedizolid, eravacycline, omadacycline were generally low for S. pneumoniae causing adult IPD.

In-vitro activity of cefiderocol, cefepime/zidebactam, cefepime/enmetazobactam, omadacycline, eravacycline and other comparative agents against carbapenem-nonsusceptible Enterobacterales: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2017-2020.

This study examined the susceptibility of carbapenem-nonsusceptible Enterobacterales (CNSE) to cefiderocol, cefepime/zidebactam, cefepime/enmetazobactam, omadacycline, eravacycline and other comparative agents. Non-duplicate Enterobacterales isolates from 16 Taiwanese hospitals were evaluated. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method, and susceptibility results were interpreted based on relevant guidelines. In total, 201 CNSE isolates were investigated, including 26 Escherichia coli isolates and 175 Klebsiella pneumoniae isolates. Carbapenemase genes were detected in 15.4% (n=4) of E. coli isolates and 47.4% (n=83) of K. pneumoniae isolates, with the most common being blaKPC (79.3%, 69/87), followed by blaOXA-48-like (13.8%, 12/87). Cefiderocol was the most active agent against CNSE; only 3.8% (n=1) of E. coli isolates and 4.6% (n=8) of K. pneumoniae isolates were not susceptible to cefiderocol. Among the carbapenem-resistant E. coli and K. pneumoniae isolates, 88.5% (n=23) and 93.7% (n=164), respectively, were susceptible to ceftazidime/avibactam. For cefepime/zidebactam, 23 (88.5%) E. coli isolates and 155 (88.6%) K. pneumoniae isolates had MICs ≤2/2 mg/L. For cefepime/enmetazobactam, 22 (84.6%) E. coli isolates and 85 (48.6%) K. pneumoniae isolates had MICs ≤2/8 mg/L. The higher MICs of K. pneumoniae against cefepime/enmetazobactam were due to only one (1.5%) of the 67 blaKPC-carrying isolates being susceptible. MICs of omadacycline were significantly higher than those of eravacycline and tigecycline. In summary, cefiderocol, ceftazidime/avibactam and cefepime/zidebactam were more effective against carbapenem-nonsusceptible E. coli and K. pneumoniae than other drugs, highlighting their potential as valuable therapeutics.

Antimicrobial susceptibility of bacteremic vancomycin-resistant Enterococcus faecium to eravacycline, omadacycline, lipoglycopeptides, and other comparator antibiotics: Results from the 2019-2020 Nationwide Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

Multicenter surveillance of antimicrobial susceptibility was performed for 235 vancomycin-resistant Enterococcus faecium (VREfm) isolates from 18 Taiwanese hospitals. The minimum inhibitory concentrations (MICs) of eravacycline, omadacycline, lipoglycopeptides, and other comparator antibiotics were determined using the broth microdilution method. Nearly all isolates of VREfm were not susceptible to teicoplanin, dalbavancin, and telavancin, with susceptibility rates of 0.5%, 1.7% and 0.5%, respectively. Tigecycline and eravacycline were active against 93.2% and 89.7% of the VREfm isolates, respectively. Moreover, the susceptibility rates of quinupristin/dalfopristin, tedizolid, and linezolid were 59.1%, 84.2%, and 77.4%, respectively. Additionally, 94% of the VREfm isolates were classified as susceptible to daptomycin, and the MICs of omadacycline required to inhibit VREfm growth by 50% and 90% were 0.12 and 0.5 mg/L, respectively. Susceptibility rates of VREfm isolates to synthetic tetracyclines and daptomycin were slightly lower and to oxazolidinone-class antibiotics were much lower in Taiwan than those in other parts of the world. Continuous monitoring of VREfm resistance to novel antibiotics, including synthetic tetracyclines, oxazolidinone-class antibiotics, and daptomycin, is needed in Taiwan.

National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.

Nosocomial Severe Bacterial Infection After Cardiac Surgery for Complex Congenital Heart Disease in Heterotaxy Syndrome.

BACKGROUND: Patients with heterotaxy syndrome (HS), commonly associated with hyposplenism and complex congenital heart disease (CCHD), require multiple-stage single ventricle type operation for long-term survival. Although a higher risk of community-acquired sepsis and mortality rate was reported in CCHD with HS compared with those without HS, whether the risk of postoperative severe bacterial infection (SBI) is higher in patients with HS remains unknown. METHOD: All patients with CCHD (with and without HS) born between 2001 and 2013 who received cardiac surgery between 2001 and 2018 were enrolled. We analyzed the epidemiology and risk of postoperative SBI in this CCHD cohort. RESULT: In total, 101 patients of CCHD with HS and 164 patients without HS were enrolled. The mean postoperative nosocomial SBI rate was 0.73/100 patient-days in patients with HS and 0.56/100 patient-days in patients without HS (P = 0.13). Multivariate Cox regression analysis demonstrated that the most critical risk factor for postoperative SBI was postoperative intubation >14 days. Preoperative risk factors, including a nonstandard surgical procedure and multiple surgeries, but not HS, were associated with an increased risk of postoperative nosocomial SBI. The pathogens of infection were also similar between these 2 groups. CONCLUSION: Although commonly associated with hyposplenism, patients with HS have similar postoperative SBI risk and pathogens as those with CCHD alone.

Reference levels for glucose-6-phosphate dehydrogenase enzyme activity in infants 7-90 days old in Taiwan.

BACKGROUND: Nationwide newborn screening for glucose-6-phosphate dehydrogenase (G6PD) deficiency has been implemented in Taiwan since 1987 and the G6PD enzyme activity levels were applied for diagnosis confirmation. As the reference value of G6PD enzyme activity was not available for infants aged 7-90 days, this study was performed to determine the enzyme level in different genotypes. METHODS: Between January 1, 2016 and June 30, 2017, 410 term infants aged 7-90 days old visiting National Taiwan University Hospital Hsinchu branch were enrolled. The comparisons of G6PD enzyme activities among genotype groups were performed. RESULTS: G6PD enzyme activity was negatively correlated with age (R = -0.212, p = 0.01). For infants under 30 days of age, the G6PD enzyme activity levels were 1.4 ± 0.9 U/g Hb in hemizygotes (n = 76), 6.5 ± 2.0 U/g Hb in heterozygotes (n = 47), and 13.6 ± 3.7 U/g Hb in those without G6PD mutations (n = 70). Among infants more than 30 days old, G6PD enzyme activity levels were 0.9 ± 0.5 U/g Hb in hemizygotes (n = 46), 6.0 ± 2.7 U/g Hb in heterozygotes (n = 23), and 11.7 ± 3.4 U/g Hb in those without G6PD mutations (n = 148). G6PD levels differed significantly among the groups defined by genotypes. CONCLUSION: We determined G6PD enzyme activity levels in infants aged between 7 and 90 days in Taiwan. Completing the reference data and determining the cutoff values for different G6PD deficiency disease statuses will help pediatricians to make accurate diagnoses.

Nationwide surveillance of antimicrobial resistance among clinically important Gram-negative bacteria, with an emphasis on carbapenems and colistin: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2018.

Multicentre surveillance of antimicrobial susceptibility of clinically important Gram-negative bacteria (GNB) from 16 Taiwanese hospitals was performed. Escherichia coli (n = 398), Klebsiella pneumoniae (n = 346), Pseudomonas aeruginosa (n = 252) and Acinetobacter baumannii complex (ABC) (n = 188) bloodstream isolates, non-typhoidal Salmonella (n = 230) and Shigella flexneri (n = 18) from various sources were collected. Antimicrobial MICs were determined using broth microdilution. Genes encoding K. pneumoniae carbapenemases (KPCs), New Delhi metallo-ß-lactamases (NDMs), Verona integron-encoded metallo-ß-lactamase (VIM), OXA-48-like carbapenemase (OXA-48) as well as mcr-1-5 genes were detected by molecular methods. Rates of carbapenem non-susceptibility were 2.8%, 9.0%, 0.4%, 0%, 10.3% and 48.8% for E. coli, K. pneumoniae, Salmonella, Shigella, P. aeruginosa and ABC, respectively. For carbapenemases, one (0.3%) E. coli harboured blaNDM-1. Fifteen (4.3%), two (0.6%) and two (0.6%) K. pneumoniae contained blaKPC, blaOXA-48 and blaVIM, respectively. Two (0.5%) E. coli and fourteen (4.0%) K. pneumoniae were non-wild-type according to the colistin MIC. Among Enterobacteriaceae with a colistin MIC ≥ 2 mg/L, mcr-1 was detected in one E. coli, two K. pneumoniae and three Salmonella spp. All three mcr-1-positive Salmonella isolates were collected from community-acquired infections; none of the six mcr-1-positive Enterobacteriaceae were carbapenem-resistant. Carbapenem resistance has increased among clinically important GNB, especially among hospital-acquired infections. blaKPC, especially the blaKPC-2 variant, was detected in approximately one-half of the carbapenem-resistant K. pneumoniae isolates in this study. Although resistance rates to colistin remained low among Enterobacteriaceae, the finding of mcr-1 from different species raises concern of potential dissemination.

In vitro activity of ceftazidime-avibactam, ceftolozane-tazobactam, and other comparable agents against clinically important Gram-negative bacilli: results from the 2017 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

OBJECTIVES: We investigated the in vitro antimicrobial susceptibilities of clinically important Gram-negative bacteria (GNB) from 16 major teaching hospitals in Taiwan in 2017. MATERIALS AND METHODS: Escherichia coli (n=686) and Klebsiella pneumoniae bloodstream isolates (n=673), non-typhoid Salmonella (NTS; n=221) from various sources, Shigella species (n=21) from fecal samples, and Neisseria gonorrhoeae (n=129) from the genitourinary tract were collected. Antibiotic minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. Alleles encoding K. pneumoniae carbapenemases (KPCs), New Delhi metallo-ß-lactamases (NDMs), Verona integron-encoded metallo-ß-lactamase, imipenemase, OXA-48-like, and mcr-1-5 genes were detected by molecular methods in Enterobacteriaceae isolates. RESULTS: Five (0.7%) E. coli isolates harbored mcr-1 alleles. Twenty-four (3.6%), seven (1.0%), four (0.6%), and one (0.15%) K. pneumoniae isolates contained bla KPC, bla OXA-48-like, mcr-1, and bla NDM, respectively. Three (1.4%) NTS and no Shigella isolates harbored mcr-1 genes. Seventy-one (10.5%) K. pneumoniae isolates displayed non-susceptibility (NS) to carbapenem agent(s). Phenotypically extended-spectrum ß-lactamase (ESBL)-producing K. pneumoniae isolates showed significantly higher rates of ertapenem, tigecycline, and ceftolozane-tazobactam (CLZ- TAZ) NS (40.2%, 16.3%, and 71%-80%, respectively) than E. coli isolates exhibiting ESBL phenotypes (5.4%, 0.7%, and 18%-28%, respectively). All phenotypically ESBL-producing E. coli isolates were ceftazidime-avibactam (CAZ-AVB) susceptible. Two (8.3%) KPC-producing K. pneumoniae isolates showed CAZ-AVB NS. Hospital-acquired K. pneumoniae isolates were significantly less susceptible to ertapenem and CLZ-TAZ than hospital-acquired E. coli isolates. CONCLUSION: Third-generation cephalosporins remain the optimal choice for treating NTS, Shigella, and gonococcal infections in Taiwan. Hospital-acquired and phenotypically ESBL-producing K. pneumoniae are a heavy resistance burden in Taiwan.

In vivo inhibition of influenza A virus replication by RNA interference targeting the PB2 subunit via intratracheal delivery.

BACKGROUND: Influenza virus infection is a major threat to human health. Small interfering RNA (siRNA) is a promising approach for the prevention and treatment of viral infections. In this study, we constructed a series of DNA vector-based short hairpin RNAs (shRNAs) that target various genes of the influenza A virus using the polymerase III U6-RNA promoter to prevent influenza virus infection in vitro and in a mouse model. RESULTS: Three sets of DNA vector-based shRNA, two targeting genes encoding the polymerase acidic protein (PA) and one targeting polymerase basic protein 2 (PB2), efficiently inhibited the replication of influenza virus A/WSN/33(H1N1) in vitro. We also successfully prevented influenza virus A/WSN/33(H1N1) infection in a C57BL/6 mouse model by intratracheal delivery of anti-PB2 shRNA. CONCLUSIONS: Our findings suggest that the PB2-targeting shRNA plasmid showed potential for use as an RNAi-based therapeutic for influenza virus infection.

Infectious complications in children with acute lymphoblastic leukemia treated with the Taiwan Pediatric Oncology Group protocol: A 16-year tertiary single-institution experience.

BACKGROUND: Infection is a major complication in pediatric patients with acute lymphoblastic leukemia during chemotherapy. In this study, the infection characteristics were determined and risk factors analyzed based on the Taiwan Pediatric Oncology Group (TPOG) acute lymphoblastic leukemia (ALL) protocol. PROCEDURE: We retrospectively reviewed fever events during chemotherapy in 252 patients treated during two consecutive clinical trials at a single institution between 1997 and 2012. Patients were classified as standard, high, and very high risk by treatment regimen according to the TPOG definitions. We analyzed the characteristics and risk factors for infection. RESULTS: Fever occurred in 219 patients (86.9%) with a mean of 2.74 episodes per person. The fever events comprised 64% febrile neutropenia, 39% clinically documented infections, and 44% microbiologically documented infections. The microbiologically documented infections were mostly noted during the induction phase and increased in very high risk patients (89 vs. 24% and 46% in standard-risk and high-risk patients, respectively). Younger age and higher risk (high-risk and very high risk groups) were risk factors for fever and microbiologic and bloodstream infections. Female gender and obesity were additive risk factors for urinary tract infection (odds ratios = 3.52 and 3.24, P < 0.001 and P = 0.004, respectively). CONCLUSIONS: Infections developed primarily during the induction phase, for which younger age and higher risk by treatment regimen were risk factors. Female gender and obesity were additive risk factors for urinary tract infection.

Pneumococcal vaccination and efficacy in patients with heterotaxy syndrome.

BackgroundPneumococcal vaccines, including pneumococcal polysaccharide vaccine (PPV) and pneumococcal conjugated vaccine (PCV), are crucial in preventing invasive pneumococcal diseases. We analyzed the pneumococcal vaccination rate, efficacy, and durability in patients with heterotaxy.MethodsAll patients with heterotaxy and CCHD who were followed up at our institution between 2010 and 2015 were included. Pneumococcal vaccine status and geometric mean concentration (GMC) of serotypes 6B, 14, 19F, and 23F were analyzed. Splenic function was considered abnormal when the percentage of IgM memory B cell was less than 1%.ResultsThe GMCs of the four serotypes did not differ significantly between patients with heterotaxy and those with CCHD; the GMCs were also not affected by abnormal splenic function. Most patients had GMCs >0.35 µg/ml (protection level) 4-5 years after either PPV or PCV injection; however, it may decay gradually in some serotypes. In addition, 21.4% of 42 patients with heterotaxy did not receive pneumococcal vaccine, and none completely adhered to the vaccine guidelines.ConclusionsVaccine efficacy was acceptable, even in patients with abnormal splenic function. In some patients, the durability of PPV and PCV decreased with time, highlighting the importance of booster doses. Vaccination rate in patients with heterotaxy is unsatisfactory.

Lack of Pertussis Protective Antibodies in Healthcare Providers Taking Care of Neonates and Infants in a Children's Hospital.

Contact tracing and seroepidemiologic studies were done after a premature baby contracted pertussis in a children's hospital. No infection source was confirmed. Four (3.5%) healthcare providers were positive for anti-pertussis IgM, while only 23% (26/113) were positive for IgG in a following survey. Pertussis vaccination for healthcare providers is needed.

Risk of Respiratory Syncytial Virus Infection in Cyanotic Congenital Heart Disease in a Subtropical Area.

OBJECTIVE: To compare the risk of respiratory syncytial virus (RSV)-associated hospitalization and analyze the epidemiology of RSV infection in patients with cyanotic and acyanotic congenital heart disease (CHD), we analyzed the nationwide health insurance database from 2005-2010. STUDY DESIGN: This study included 1050 patients with cyanotic CHD and 7077 patients with acyanotic CHD. Patients with acyanotic CHD were further classified into hemodynamically significant (hs)-acyanotic and non-hs-acyanotic groups according to whether they underwent surgery or took at least 2 anticongestive medications. RESULTS: RSV-associated hospitalization was higher in the cyanotic group than in hs-acyanotic and non-hs-acyanotic groups both before 1 year of age (4.8% vs 2.1% vs 1.5%, P < .001) and between 1 and 2 years of age (0.9% vs 0.56% vs 0.14%, P = .003). The hospitalization duration, intensive care, ventilator support prevalence, hospitalization cost, and mortality rate were significantly higher in the cyanotic group than in the other 2 groups. Logistic regression revealed that cyanotic CHD was the most significant risk factor for the ventilator support and RSV-associated mortality. In both patients with cyanotic and acyanotic CHD, RSV-associated hospitalization rate was higher in patients aged younger than 1 year and in spring and autumn in Taiwan, a subtropical country. CONCLUSIONS: The results show that patients with cyanotic CHD have a higher risk of severe RSV infection than do those with acyanotic CHD. RSV prophylaxis is more important and may reduce costs more for patients with cyanotic CHD.

Low immunoglobulin M memory B-cell percentage in patients with heterotaxy syndrome correlates with the risk of severe bacterial infection.

BACKGROUND: Patients with heterotaxy syndrome, commonly associated with complex congenital heart disease (CHD), exhibit a higher risk of severe bacterial infection (SBI). We sought to define the change of a novel immunologic marker, the immunoglobulin M (IgM) memory B-cell percentage, and its association with SBI. METHODS: We enrolled 46 (M/F 29/17) heterotaxy syndrome patients (42 right atrial isomerism (RAI) and 4 left atrial isomerism (LAI)) aged > 1 y during the period 2010-2012 in a tertiary care center. We analyzed IgM(+)CD27(+) memory B-cell percentages. Patients with simple and complex CHD served as controls. RESULTS: The mean IgM memory B-cell percentages were the lowest in the heterotaxy syndrome group, compared with those in complex and simple CHD groups (1.8 ± 2.1 vs. 3.9 ± 3.2 vs. 5.1 ± 4.7, P < 0.001). In the heterotaxy syndrome group, 41.3% had low IgM memory B-cell percentages (<1% of B cells). Seven had a history of community-acquired SBI and 85.7% of these had low IgM memory B-cell percentages, which was the only significant factors related to community-acquired SBI (P = 0.028). CONCLUSION: The memory B cell and IgM memory B-cell percentages are low in patients with heterotaxy syndrome, and the presence of IgM memory B-cell percentage < 1% correlates with community-acquired SBI.