Impact of public health measures and new introducing variants on Respiratory syncytial virus recrudescence in Taiwan during the COVID-19 pandemic.

OBJECTIVES: Respiratory syncytial virus (RSV) causes clinically significant distress in children and adults. Non-pharmaceutical interventions against SARS-CoV-2 have affected the seasonal activity of common respiratory pathogens. This seems exceptionally true regarding RSV's seasonal circulation, hence we have investigated the changes in the epidemiology of RSV in Taiwan during the pandemic. MATERIALS: A prospective surveillance of RSV among hospitalized children was carried out between 2020 and 2022 in central Taiwan. Of all PCR-detected RSV, genotype and evolutionary analysis were further investigated. Demographics and clinical features were compared between each outbreak. RESULTS: Throughout the consecutive three years of the SARS-CoV-2 pandemic, RSV outbreaks took place in Taiwan first in 2020 and a second time in 2022. We enrolled 80 and 105 hospitalized child cases, in each surge respectively. The RSV G protein genomic analysis revealed that RSV ON1 and RSV BA9 were separately contributing to these two outbreaks, and evolutionary evidence indicated these RSV variants are new to Taiwan, with their own featured sets of mutations. Clinically, a shift in age of RSV infected children was found, but the clinical severity was not worse and remained independent of RSV genotype. CONCLUSIONS: There were two delayed RSV surges after the relaxation of public measures during the pandemic in Taiwan, and both outbreaks were driven by new RSV genetic variants rather than cryptic circulation of the previous genetic clusters in Taiwan. These findings highlight the importance of continued surveillance on the trend and evolution of RSV after the COVID-19 pandemic.

Delayed respiratory syncytial virus outbreak in 2020 in Taiwan was correlated with two novel RSV-A genotype ON1 variants.

BACKGROUND: Human respiratory syncytial virus (RSV) is a leading pathogen of acute respiratory tract disease among infants and young children. Compared with previous seasons, RSV outbreaks in Taiwan during the 2020-2021 season were delayed because of COVID-19 mitigation measures. We conducted this study to determine the association of viral factors with clinical characteristics of preschool children with RSV infection. METHODS: We performed a molecular epidemiology analysis of RSV among inpatient preschool children in Taiwan. In 80 nasopharyngeal samples positive for RSV, we sequenced and analyzed viral genotypes according to patient data. Patients' clinical data were obtained from medical files, and their clinical profiles were compared with those of RSV cases recorded during the 2014-2017 seasons. RESULTS: Phylogenetic analysis revealed that among the RSV-positive samples, all RSV strains identified during the 2020-2021 season belonged to the ON1 genotype. Most of the Taiwan ON1 strains were categorized into two well-supported clusters with distinct G protein amino acid substitution patterns that had never been demonstrated previously. Furthermore, the proportion of cases among children aged >24 months increased (P < 0.001). Compared with patients infected during the 2014-2017 seasons, patients infected during the 2020-2021 season were hospitalized for shorter days from hospital admission to dereference (P = 0.004) and had a greater need for oxygen supplements (P = 0.021) and systemic steroid therapy (P = 0.026). CONCLUSION: The delayed 2020-2021 RSV outbreak in Taiwan was caused by two novel RSV ON1.1 variants. How the change in RSV epidemiology affects future RSV outbreaks warrants exploration.

Sequence types 8, 59, and 45 methicillin resistant Staphylococcus aureus as the predominant strains causing skin and soft tissue infections in Taiwan's prisons and jails.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is the predominant cause of skin and soft tissue infections (SSTIs), which is a problem in prisons and jails. We conducted this study to understand MRSA molecular characteristics among inmates with SSTIs, and we chose MRSA isolates from a community hospital as a comparison. METHODS: A total of 219 MRSA isolates from three custodial facilities and 134 isolates from a community hospital in Taiwan were collected in the 2017 calendar year. MRSA isolates were investigated molecularly by staphylococcal chromosome cassette mec (SCCmec) type, mupirocin, and chlorhexidine genotypical resistance, and multi-locus sequence typing (ST). RESULTS: Of the 219 MRSA isolates from custodial facilities, SCCmec IV was the most prevalent type (65.3%), followed by type VT (32.4%) and type V (1.8%). Regarding sequence types, ST59 (36.4%), 8 (35.3%), and 45 (17.9%) were the leading three predominant types out of 184 selected MRSA isolates, and ST45 MRSA was more prevalent in custodial facilities (p = 0.019). The antimicrobial resistance rates varied for different MRSA strains, with ST45 MRSA having the lowest rates of resistance to most antimicrobials. Overall, 91.5% of isolates carried mupA gene and 25.8% were positive for qacA/B gene, this was independent of the MRSA sequence types. CONCLUSIONS: ST59, ST8, and ST45 MRSA are the leading three MRSA strains causing SSTIs in Taiwan, 2017, but the molecular distribution varied distinctly between the custodial facilities and hospital settings. The genotypical mupirocin resistance rate is quite high in this study. The frequency of chlorhexidine resistance gene is relatively low, especially in MRSA isolates from custodial facilities.

Macrolide Resistance, Clinical Features, and Cytokine Profiles in Taiwanese Children With Mycoplasma pneumoniae Infection.

BACKGROUND: The factors that predict the progression of Mycoplasma pneumoniae infection remain inconclusive. Therefore, we investigated macrolide resistance prevalence, M pneumoniae genotype, and clinical characteristics of childhood M pneumoniae respiratory tract infections in Taiwan. METHODS: A total of 295 children hospitalized with respiratory tract infections with positive serological M pneumoniae immunoglobulin M test results were enrolled in this 3-year prospective study. Oropharyngeal swabs were obtained for M pneumoniae cultures and polymerase chain reaction tests. All M pneumoniae specimens were further characterized by P1 typing, multilocus variable-number tandem-repeat analysis (MLVA), and macrolide resistance genotyping. The clinical characteristics and blood cytokine profiles were analyzed accordingly. RESULTS: Of 138 M pneumoniae specimens, type I P1 was the predominant (136 of 138, 98.6%). The MLVA type P (4-4-5-7-2) was the leading strain (42 of 138, 30.4%), followed by type J, U, A, and X. The overall macrolide-resistant rate was 38.4% (53 of 138); the resistance rate increased dramatically yearly: 10.6% in 2017, 47.5% in 2018, and 62.5% in 2019 (P < .001). All macrolide-resistant M pneumoniae (MRMP) harbored the A2063G mutation and were MLVA type 4-5-7-2 (49 of 53, 92.5%), especially type U and X. No significant differences in clinical symptoms, duration of hospital stay, and radiographic findings were identified among patients between MRMP and macrolide-sensitive M pneumoniae (MSMP) groups. Patients with MRMP infection had more febrile days before and during hospitalization and higher interleukin (IL)-13 and IL-33 levels than patients with MSMP infection (P < .05). CONCLUSIONS: Macrolide-resistant M pneumoniae surged in Taiwan throughout the study period, but macrolide resistance was not a determinant factor of clinical severity.

Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus among nasal carriage strains isolated from emergency department patients and healthcare workers in central Taiwan.

BACKGROUND AND OBJECTIVE: Screening and identification of methicillin-resistant Staphylococcus aureus (MRSA) carriage are helpful for controlling MRSA dissemination in hospitals. The aim of our study was to determine the prevalence of nasal carriages and diversity of MRSA among patients and healthcare workers (HCWs) at two regional hospitals in Taiwan. METHODS: Nasal swabs were obtained prospectively from 204 patients visiting the emergency department (ED) and 326 HCWs in two regional hospitals in Changhua, Taiwan, between February 2015 and June 2015. All the MRSA isolates were further molecularly characterized. RESULTS: Of the 204 participating patients, the nasal carriage rates of S. aureus and MRSA were 22.1% and 7.8%, respectively. For HCWs, the S. aureus and MRSA carriage rates were 26.1% and 6.1%, respectively. There was no statistically significant difference in MRSA carriage rate between patients and HCWs (P = 0.447). Patients receiving hemodialysis were significantly associated with MRSA colonization (P = 0.012). The leading three sequence types (ST) were ST59 (16, 44.4%), ST45 (11, 30.6%), and ST239 (3, 8.3%) for all 36 MRSA isolates. ST59/SCCmec IV/t437/PVL-negative and ST45/SCCmec V/t1081/PVL-negative were the predominant clones among HCWs (30%) and participating patients (19%), respectively. CONCLUSION: Overall, a substantial proportion of patients visiting the ED and HCWs harbored CA-MRSA, mostly ST59 strains, in their nares. It is noteworthy that MRSA ST45 strains supplanted ST239 as the second leading nasal MRSA colonization strain in our study.

Comparison of molecular epidemiology of bloodstream methicillin-resistant Staphylococcus aureus isolates between a new and an old hospital in central Taiwan.

OBJECTIVE: To compare the molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolates between an old, urban hospital and a new, rural hospital over the same time period. METHODS: The molecular characteristics of 398 MRSA bloodstream isolates collected between 2007 and 2013 from two hospitals in Taiwan were analyzed retrospectively; 202 isolates were from the old hospital and 196 from the new hospital (opened in 2007). RESULTS: The rate of resistance to multiple antibiotics was significantly higher in the old hospital (93%) than in the new hospital (81%) (p<0.001). Genetic community-associated MRSA carrying staphylococcal cassette chromosome (SCC) type IV or V accounted for 58% of all MRSA isolates in the new hospital, significantly higher than the rate in the old hospital (p=0.018). The rate of spa t037-SCCmec III MRSA was significantly lower in the new hospital than in the old hospital (p=0.02). A significant decreasing trend in spa t002-SCCmec II MRSA isolates was observed in the old hospital (p=0.006), while the proportion of spa t037-SCCmec III MRSA decreased significantly in the new hospital (41.7% to 26.1%, p=0.022). CONCLUSIONS: The rate of multiple antibiotic resistance and the molecular characteristics of MRSA differed significantly between the old and new hospitals and changed over time.

Treatment of recurrent complicated urinary tract infections in children with vesicoureteral reflux.

BACKGROUND: Urinary tract infections (UTIs) in children with vesicoureteral reflux (VUR) are often caused by uropathogens with a high rate of drug resistance and are associated with a high rate of recurrence with a single pathogen. In this study, we evaluated the incidence of recurrent UTI and the drug resistance pattern of Escherichia coli in children with VUR. We also evaluated whether combination therapy comprising fosomycin plus one other antimicrobial agent is effective for treatment of recurrent UTIs. METHODS: We retrospectively reviewed the medical records of all children with VUR who developed at least one episode of UTI during the period January 1, 2003 to December 31, 2013 at a single medical center. The effectiveness of fosfomycin plus amikicin for Enterobacteriaceae or ceftazidime for Pseudomonas aeruginosa infections was prospectively studied in six children with recurrent relapsing UTIs. RESULTS: The study population comprised 129 children (age range, from 1month to 15 years; mean ± standard deviation, 2.37 ± 2.91 years) with VUR who developed at least one UTI during the 10-year study period; 68 (52.7%) had recurrent UTIs. The presence of an underlying urinary tract anomaly was predictive of recurrence (p = 0.028). The rates of susceptibility of E. coli to cefazolin (p < 0.001) and cefotaxime (p < 0.001) were significantly lower in patients with recurrent UTIs. Combination therapy with fosfomycin plus amikacin or ceftazidime was shown to be an effective therapeutic option for recurrent UTIs due to a single uropathogen. CONCLUSION: The rates of susceptibility of E. coli to commonly used antimicrobials were significantly lower in children who developed more than one episode of UTI. The empiric choice of cefazolin or cefotaxime was usually ineffective. Administration of fosfomycin plus amikacin or ceftazidime was an effective therapeutic and preventive strategy in children with VUR and recurrent relapsing UTI.