Children with Mycoplasma pneumoniae infection in Taiwan: Changes in molecular characteristics and clinical outcomes.

BACKGROUND: Mycoplasma pneumoniae is a pathogen that causes respiratory diseases in children. Infections caused by M. pneumoniae are usually self-limited but occasionally can be severe. We observed emerging cases of severe mycoplasma infection requiring extracorporeal membrane oxygenation (ECMO). Thus, we investigated chronological changes in the molecular features of the M. pneumoniae and its clinical impacts among the pediatric population. METHODS: From 2011 to 2019, respiratory samples were collected from patients younger than 18 years old with pneumonia in a tertiary children's hospital. Focused multiple-locus variable number of tandem repeats analysis (MLVA) typing was performed on samples positive for M. pneumoniae in 2016 and 2019. Clinical data from the patients' electronic medical records were collected. We described the annual trend of macrolide resistance and MLVA type and analyzed the associations between clinical manifestations and MLVA types. RESULTS: The percentage of macrolide-resistant (MLR) M. pneumoniae gradually increased from 22% (27/122) in 2015 to 70% (82/117) in 2019. Among the MLRM. pneumoniae, the predominant strain shifted from type P (31% [13/42]) to type A (40% [19/46]). The demographics, initial presentations, and clinical courses of the subjects with MLRM. pneumoniae did not differ significantly between 2011 and 2019. However, in 2019, two fulminant cases requiring venovenous ECMO were observed, which indicates that more attention to the clinical severity of MLRM. pneumoniae infections is warranted. CONCLUSION: Obtaining accurate information on macrolide susceptibility is crucial for physicians to initiate appropriate antibiotic treatment in a timely fashion. Although we could not identify significant differences among mycoplasma pneumonias caused by different MLVAs over a span of 9 years, the emergence of severe mycoplasma infections requiring ECMO was clinically significant, and further monitoring was required.

Multiple-locus variable-number tandem-repeat analysis (MLVA) of macrolide-susceptible and -resistant Mycoplasma pneumoniae in children in Taiwan.

BACKGROUND/PURPOSE: To date, molecular typing studies on Mycoplasma pneumoniae are limited. We evaluated the molecular types of Mycoplasma pneumoniae in pediatric patients in Taiwan in 2016. METHODS: We used real-time quantitative PCR on respiratory specimens to identify M. pneumoniae in children with community-acquired pneumonia. The domain V of their 23S rRNA were sequenced for detection of macrolide-resistant point mutations. Molecular typing with multiple locus variable-number tandem repeat analysis (MLVA) was done for both macrolide-susceptible and -resistance M. pneumoniae samples. RESULTS: M. pneumoniae was detected in 22% (180/826) respiratory samples during the study period. Among all M. pneumoniae-positive samples, 24% (43/180) had harbored macrolide-resistant genotypes, and 86% (37/43) of them were A2063G mutation. Forty-two macrolide-resistant strains and 20 randomly selected macrolide-susceptible strains underwent MLVA profiling. MLVA 4-5-7-2 was the most frequent type (32/62, 52%), followed by 4-5-7-3 (17/62, 27%) and 1-5-6-2 (9/62, 15%). There was a strong association between MLVA 4-5-7-2 and macrolide resistance (p < 0.001). In contrast, M 4-5-7-3 and 1-5-6-2 were related to macrolide susceptibility (p < 0.001, and p = 0.025, respectively). CONCLUSION: Macrolide resistance was relatively low (24%) in this age group in 2016 in Taiwan, and A2063G was the dominant point mutation. MLVA 4-5-7-2 was associated with macrolide resistance.

Interference of DNAJB6/MRJ Isoform Switch by Morpholino Inhibits Replication of HIV-1 and RSV.

The molecular chaperon MRJ (DNAJB6) exhibits two splice isoforms that have different roles in human viral infection, but the regulatory mechanism of MRJ isoform expression is yet unclear. In this study, we show that reduction of the polyadenylation factor CstF64 was correlated with the increase of the MRJ large isoform (MRJ-L) in human macrophages and elucidate the mechanism underlying CstF64-modulated MRJ isoform expression. Moreover, we exploited an antisense strategy targeting MRJ-L for virus replication. A morpholino oligonucleotide complementary to the 5' splice site of MRJ intron 8 downregulated MRJ-L expression and suppressed the replication of not only HIV-1 but also respiratory syncytial virus (RSV). We demonstrated that downregulation of the MRJ-L level reduced HIV-1 replication as well as the subgenomic mRNA and viral production of RSV. The present findings that two human health-threatening viruses take advantage of MRJ-L for infection suggest MRJ-L as a potential target for broad-spectrum antiviral strategy.

Lack of resistance-associated mutations in UL54 and UL97 genes of circulating cytomegalovirus strains isolated in a medical center in Taiwan.

Human cytomegalovirus (HCMV) is a large DNA virus and a member of the betaherpesvirus family. HCMV infection is extremely common in human populations and can cause severe diseases in immunocompromised hosts. Ganciclovir is the most widely used antiviral drug for cytomegalovirus infection and works by blocking the amplification of HCMV. HCMV strains resistant to ganciclovir have been detected in recent decades and mainly result from mutations in UL97 (protein kinase) and UL54 (DNA polymerase) genes. In order to understand the prevalence of resistance of HCMV in Taiwan, we studied 40 clinical isolates to detect the mutations of UL97 and UL54 that might be related to resistance. The results showed that no mutation known to cause ganciclovir resistance was detected in any strain, but some polymorphisms (N685S, A688V, A885T, N898D in UL54; D605E in UL97) were frequently observed. Our results suggest that resistant HCMV strains are not prevalent in Taiwan.

Molecular detection and incidence of human papillomavirus in neonates: methodology and a pilot study in a medical center.

BACKGROUND/PURPOSE: Human papillomavirus (HPV) infection can cause laryngeal papillomas in children. Vertical transmission has been confirmed. This study aimed to establish a sensitive molecular diagnostic method and understand the incidence of the HPV-6 and HPV-11 in neonates with intubation. METHODS: We enrolled 108 newborns between October 2007 and January 2010. All neonates were intubated due to underlying disease. The specimens were collected via endotracheal aspiration. DNA of HPV types 6 and 11 was detected by real-time PCR and nested PCR. RESULTS: HPV-DNA was detected in eight of the 108 newborns studied. Seven respiratory specimens tested positive for HPV-11 and one was positive for HPV-6. The HPV 6/11 detection rate in neonates was 7.4% (8/108). CONCLUSION: A rapid, sensitive, specific, and reproducible RT-PCR method and nest PCR were developed for the detection and differentiation of HPV-6 and HPV-11 genomic variants in a single PCR reaction. The assays are of great value for clinical and epidemiologic studies of HPV-6 and HPV-11 infections. Neonatal HPV colonization may be related to juvenile-onset recurrent respiratory papillomatosis. The transmission route may be from mother to child. The clinical significance of neonatal carriage of HPV-6 or HPV-11 warrants further study.

Argonaute-2 enhances suppression of human cytomegalovirus replication by polycistronic short hairpin RNAs targeting UL46, UL70 and UL122.

BACKGROUND: Human cytomegalovirus (HCMV) is a common human pathogen that causes significant morbidity and mortality. The efficacy of anti-HCMV drugs such as ganciclovir, foscarnet and cidofovir is limited because of drug toxicities and frequent development of resistance. Here, we report an alternative anti-HCMV method using RNA silencing. METHODS: Combinatorial use of second-generation short hairpin RNAs (shRNA-miRs) targeting various transcripts of HCMV and an RNA-silencing endonuclease Argonaute-2 (Ago2) expression vector were applied to inhibit replication of HCMV AD169. Normal human fetal lung MRC-5 fibroblasts were transfected with pSM30-shRNA-miRs harbouring single or multiple shRNA-miR cassettes with or without Ago2 and then infected with HCMV AD169. Production of small interfering RNA (siRNA) was quantified by reverse transcription PCR. Virus secretion was evaluated by plaque reduction assays. RESULTS: The use of shRNA-miRs targeting a single HCMV gene suppressed HCMV AD169 viral titres by 50-70%. Polycistronic shRNA-miRs targeting UL46+UL122 and UL70+UL46+UL122 reached nearly 80% of inhibition. Coexpression of Ago2 with shRNA-miRs targeting UL46+UL122 and UL70+UL46+UL122 achieved a 95% reduction in viral maturation. CONCLUSIONS: Coexpression of Ago2 with shRNA-miRs enhanced the production of mature siRNAs and increased the efficiency of RNA silencing in the suppression of HCMV replication. This strategy may be universally applied to RNA interference-based therapies.

A highly stable cambialistic-superoxide dismutase from Antrodia camphorata: expression in yeast and enzyme properties.

A cDNA encoding a putative superoxide dismutase (SOD) was identified in expressed sequence tags of Antrodia camphorata, a medicinal mushroom found only in Taiwan. The deduced protein was aligned with Mn-SODs and Fe-SODs from other organisms, this SOD showed greater homology to Mn-SOD. Functional A. camphorata SOD protein was overexpressed in yeast and purified. The purified enzyme showed two active forms on a 12.5% native PAGE, a dimer and a monomer. The dimeric protein's half-life of deactivation at 80 degrees C was 7 min, and its thermal inactivation rate constant K(d) was 9.87 x 10(-2)min(-1). The enzyme was stable in a broad pH range from 5-11; in the presence of 0.4M imidazole and 2% SDS. The atomic absorption spectrometric assay showed that 1.0 atom of manganese/iron (9:1) was present in each SOD subunit. The high stability of the enzyme make it better suited than other cambialistic-SODs for use in cosmetics. The SOD also documents its future utility in developing anti-inflammatory agent and in the treatment of chronic diseases.