Breathing-Driven Self-Powered Pyroelectric ZnO Integrated Face Mask for Bioprotection.

Rapid spread of infectious diseases is a global threat and has an adverse impact on human health, livelihood, and economic stability, as manifested in the ongoing coronavirus disease 2019 (COVID-19) pandemic. Even though people wear a face mask as protective equipment, direct disinfection of the pathogens is barely feasible, which thereby urges the development of biocidal agents. Meanwhile, repetitive respiration generates temperature variation wherein the heat is regrettably wasted. Herein, a biocidal ZnO nanorod-modified paper (ZNR-paper) composite that is 1) integrated on a face mask, 2) harvests waste breathing-driven thermal energy, 3) facilitates the pyrocatalytic production of reactive oxygen species (ROS), and ultimately 4) exhibits antibacterial and antiviral performance is proposed. Furthermore, in situ generated compressive/tensile strain of the composite by being attached to a curved mask is investigated for high pyroelectricity. The anisotropic ZNR distortion in the bent composite is verified with changes in ZnO bond lengths and OZnO bond angles in a ZnO4 tetrahedron, resulting in an increased polarization state and possibly contributing to the following pyroelectricity. The enhanced pyroelectric behavior is demonstrated by efficient ROS production and notable bioprotection. This study exploring the pre-strain effect on the pyroelectricity of ZNR-paper might provide new insights into the piezo-/pyroelectric material-based applications.

Parabacteroides leei sp. nov., isolated from human blood.

An obligate anaerobic, Gram-negative, rod-shaped and non-spore-forming bacterium, designated as strain GYB001T, was isolated from the blood of a patient with a sigmoid colon perforation. Taxonomic characterization of the novel isolate was performed using a polyphasic approach. A phylogenetic analysis based on 16S rRNA gene and whole genome sequences revealed that GYB001T represented a member of the genus Parabacteroides, in the family Tannerellaceae. The closest species, based on 16S rRNA sequence, was Parabacteroides gordonii DSM 23371T with 97.4 % similarity. Average nucleotide identity and digital DNA-DNA hybridization values between strain GYB001T and P. gordonii DSM 23371T were 86.7 and 28.7% and between GYB001T and Parabacteroides faecis JCM 18682T were 86.6 and 27.7 %, respectively. The genome was 6.57 Mbp long with 43.3 mol% G+C content. Colonies on Brucella blood agar (BBA) were circular, convex, smooth, grey and small in size. Growth was observed on trypticase soy agar (TSA), TSA +5 % sheep blood and Euglena gracilis agar. Growth occurred at 18-42 °C on BBA in the presence of 0-3 % NaCl (w/v) and at pH 6.0-8.5. The major polar lipids were phosphatidylethanolamine and phospholipids. The major fatty acids in strain GYB001T were anteiso-C15 : 0 and iso-C17 : 0 3-OH, and the predominant respiratory quinones were menaquinone-10 (MK-10) and MK-9. The cell wall contained meso-diaminopimelic acid. Considering these phenotypic features and comparative genome analyses, we propose strain GYB001T as the type strain of Parabacteroides leei sp. nov. (=KCTC 25738T=KBN12P06525T=LMG 32797T).

Changing Epidemiology of Pathogenic Bacteria Over the Past 20 Years in Korea.

BACKGROUND: The epidemiology of pathogenic bacteria varies according to the socioeconomic status and antimicrobial resistance status. However, longitudinal epidemiological studies to evaluate the changes in species distribution and antimicrobial susceptibility of pathogenic bacteria nationwide are lacking. We retrospectively investigated the nationwide trends in species distribution and antimicrobial susceptibility of pathogenic bacteria over the last 20 years in Korea. METHODS: From 1997 to 2016, annual cumulative antimicrobial susceptibility and species distribution data were collected from 12 university hospitals in five provinces and four metropolitan cities in South Korea. RESULTS: The prevalence of Staphylococcus aureus was the highest (13.1%) until 2012 but decreased to 10.3% in 2016, consistent with the decrease in oxacillin resistance from 76.1% in 2008 to 62.5% in 2016. While the cefotaxime resistance of Escherichia coli increased from 9.0% in 1997 to 34.2% in 2016, E. coli became the most common species since 2013, accounting for 14.5% of all isolates in 2016. Pseudomonas aeruginosa and Acinetobacter baumannii rose to third and fifth places in 2008 and 2010, respectively, while imipenem resistance increased from 13.9% to 30.8% and 0.7% to 73.5% during the study period, respectively. Streptococcus agalactiae became the most common pathogenic streptococcal species in 2016, as the prevalence of Streptococcus pneumoniae decreased since 2010. During the same period, pneumococcal penicillin susceptibility decreased to 79.0%, and levofloxacin susceptibility of S. agalactiae decreased to 77.1% in 2016. CONCLUSION: The epidemiology of pathogenic bacteria has changed significantly over the past 20 years according to trends in antimicrobial resistance in Korea. Efforts to confine antimicrobial resistance would change the epidemiology of pathogenic bacteria and, consequently, the diagnosis and treatment of infectious diseases.

Ultrasensitive Isothermal Detection of SARS-CoV-2 Based on Self-Priming Hairpin-Utilized Amplification of the G-Rich Sequence.

The outbreak of the novel coronavirus disease 2019 (COVID-19) pandemic induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of fatalities all over the world. Unquestionably, the effective and timely testing for infected individuals is the most imperative for the prevention of the ongoing pandemic. Herein, a new method was established for detecting SARS-CoV-2 based on the self-priming hairpin-utilized isothermal amplification of the G-rich sequence (SHIAG). In this strategy, the target RNA binding to the hairpin probe (HP) was uniquely devised to lead to the self-priming-mediated extension followed by the continuously repeated nicking and extension reactions, consequently generating abundant G-rich sequences from the intended reaction capable of producing fluorescence signals upon specifically interacting with thioflavin T (ThT). Based on the unique isothermal design concept, we successfully identified SARS-CoV-2 genomic RNA (gRNA) as low as 0.19 fM with excellent selectivity by applying only a single HP and further verified its practical diagnostic capability by reliably testing a total of 100 clinical specimens for COVID-19 with 100% clinical sensitivity and specificity. This study would provide notable insights into the design and evolution of new isothermal strategies for the sensitive and facile detection of SARS-CoV-2 under resource constraints.

Detection of Clostridioides difficile toxin B gene: benefits of identifying gastrointestinal pathogens by mPCR assay in the diagnosis of diarrhea in pediatric patients.

BACKGROUND: In the pediatric population, severe Clostridioides difficile infection (CDI) sometimes occurs, but most cases are asymptomatic. The asymptomatic carriage rate in pediatric populations is reportedly higher than in the adult population. It is difficult to diagnose CDI, even if C. difficile is detected in children with diarrhea. This study aimed to evaluate the positivity rate of toxigenic C. difficile in the pediatric population with diarrhea. METHODS: We collected and retrospectively analyzed gastrointestinal pathogen multiplex PCR results of 960 patients to estimate the positivity rate of toxigenic C. difficile in pediatric populations aged between 0 and 18 years. RESULTS: The overall rate of C. difficile toxin B positivity was 10.1% in the stool samples. The positivity rate peaked in 1-year-old infants (29/153, 19.0%) and continually decreased thereafter. The positivity rate we observed was lower than the rates described in the literature. Remarkably, no C. difficile was detected in neonates. Antibiotic usage was inversely related to the positivity rate, especially in infants < 2 years of age. The odds ratio of antibiotics was 0.44 (95% confidence interval (CI) 0.28-0.68; P < 0.001). The presence of concomitant gastrointestinal pathogens was not associated with toxigenic C. difficile positivity. CONCLUSIONS: Even though toxigenic C. difficile infection is neither an important nor a common cause of pediatric diarrhea, children can spread it to adults at risk of developing CDI. The pediatric population can act as hidden reservoirs for pathogenic strains in the community.

FRET-based hACE2 receptor mimic peptide conjugated nanoprobe for simple detection of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has led to a pandemic of acute respiratory disease, namely coronavirus disease (COVID-19). This disease threatens human health and public safety. Early diagnosis, isolation, and prevention are important to suppress the outbreak of COVID 19 given the lack of specific antiviral drugs to treat this disease and the emergence of various variants of the virus that cause breakthrough infections even after vaccine administration. Simple and prompt testing is paramount to preventing further spread of the virus. However, current testing methods, namely RT-PCR, is time-consuming. Binding of the SARS-CoV-2 spike (S) glycoprotein to human angiotensin-converting enzyme 2 (hACE2) receptor plays a pivotal role in host cell entry. In the present study, we developed a hACE2 mimic peptide beacon (COVID19-PEB) for simple detection of SARS-CoV-2 using a fluorescence resonance energy transfer system. COVID19-PEB exhibits minimal fluorescence in its ''closed'' hairpin structure; however, in the presence of SARS-CoV-2, the specific recognition of the S protein receptor-binding domain by COVID19-PEB causes the beacon to assume an ''open'' structure that emits strong fluorescence. COVID19-PEB can detect SARS-CoV-2 within 3 h or even 50 min and exhibits strong fluorescence even at low viral concentrations, with a detection limit of 4 × 103 plaque-forming unit/test. Furthermore, in SARS-CoV-2-infected patient samples confirmed using polymerase chain reaction, COVID19-PEB accurately detected the virus. COVID19-PEB could be developed as a rapid and accurate diagnostic tool for COVID-19.

Open-Bandgap Graphene-Based Field-Effect Transistor Using Oligo(phenylene-ethynylene) Interfacial Chemistry.

Organic interfacial compounds (OICs) are required as linkers for the highly stable and efficient immobilization of bioprobes in nanobiosensors using 2D nanomaterials such as graphene. Herein, we first demonstrated the fabrication of a field-effect transistor (FET) via a microelectromechanical system process after covalent functionalization on large-scale graphene by introducing oligo(phenylene-ethynylene)amine (OPE). OPE was compared to various OICs by density functional theory simulations and was confirmed to have a higher binding energy with graphene and a lower band gap than other OICs. OPE can improve the immobilization efficiency of a bioprobe by forming a self-assembly monolayer via anion-based reaction. Using this technology, Magainin I-conjugated OGMFET (MOGMFET) showed a high sensitivity, high selectivity, with a limit of detection of 100  cfu mL-1 . These results indicate that the OPE OIC can be applied for stable and comfortable interfacing technology for biosensor fabrication.

Microbiome and mycobiome interaction in house dust mites and impact on airway cells.

BACKGROUND: Major allergen sources Dermatophagoides farinae, Dermatophagoides pteronyssinus and Tyrophagus putrescentiae have been reported to have distinct microbiomes. The purpose of this study was to investigate the effect of each mite on airway epithelial cells as a model of airway allergic disease. METHODS: Transcriptomic analysis (RNA-seq) of an airway epithelial cell line (BEAS-2B) was performed to compare gene expression patterns after treatment with extracts of three mite species (D. farinae, D. pteronyssinus and T. putrescentiae). In addition, mycobiome deep sequencing of mites was employed to identify fungal species that interact with the microbiomes of the mites. RESULTS: Immune responses to bacteria were enriched only in the D. farinae-treated group as this species harboured larger numbers of bacteria than the other mites, and the high level of LPS in D. farinae caused proinflammatory cytokine production in airway epithelial cells. In addition, antibiotic metabolism pathways were enriched in D. pteronyssinus-treated cells but not in D. farinae -treated cells. Subsequent experiments revealed that D. pteronyssinus had a high fungal load that inhibited bacterial survival in this mite species. CONCLUSION: The large amount of bacteria in D. farinae causes airway epithelial cells to produce more allergy-related cytokines than D. pteronyssinus, since fungi present in D. pteronyssinus suppress the abundance of mite-associated bacteria.

Role of AmpG in the resistance to ß-lactam agents, including cephalosporins and carbapenems: candidate for a novel antimicrobial target.

BACKGROUND: A complex cascade of genes, enzymes, and transcription factors regulates AmpC ß-lactamase overexpression. We investigated the network of AmpC ß-lactamase overexpression in Klebsiella aerogenes and identified the role of AmpG in resistance to ß-lactam agents, including cephalosporins and carbapenems. METHODS: A transposon mutant library was created for carbapenem-resistant K. aerogenes YMC2008-M09-943034 (KE-Y1) to screen for candidates with increased susceptibility to carbapenems, which identified the susceptible mutant derivatives KE-Y3 and KE-Y6. All the strains were subjected to highly contiguous de novo assemblies using PacBio sequencing to investigate the loss of resistance due to transposon insertion. Complementation and knock-out experiments using lambda Red-mediated homologous recombinase and CRISPR-Cas9 were performed to confirm the role of gene of interest. RESULTS: In-depth analysis of KE-Y3 and KE-Y6 revealed the insertion of a transposon at six positions in each strain, at which truncation of the AmpG permease gene was common in both. The disruption of the AmpG permease leads to carbapenem susceptibility, which was further confirmed by complementation. We generated an AmpG permease gene knockout using lambda Red-mediated recombineering in K. aerogenes KE-Y1 and a CRISPR-Cas9-mediated gene knockout in multidrug-resistant Klebsiella pneumoniae-YMC/2013/D to confer carbapenem susceptibility. CONCLUSIONS: These findings suggest that inhibition of the AmpG is a potential strategy to increase the efficacy of ß-lactam agents against Klebsiella aerogenes.

Evaluation of Disk carbapenemase test using improved disks for rapid detection and differentiation of clinical isolates of carbapenemase-producing Enterobacterales.

OBJECTIVES: Rapid detection of carbapenemase-producing Enterobacterales (CPE) is important to control spread of the resistance. We previously reported that imipenem disks prepared from injectable imipenem-cilastatin could rapidly detect KPC- and NDM-type carbapenemases. In the present study, we evaluated performance of disks of IPM and combined disks of imipenem-tazobactam and imipenem-EDTA, which were prepared from powders of imipenem and inhibitors. METHODS: Isolates of Enterobacterales were recovered from specimens of patients at a tertiary care hospital in Korea during January 2017 and March 2018. Routine CPE detection was performed by the CPE surveillance personnel whereas evaluation of the Disk carbapenemase test (DCT) was performed by the other personnel without knowing the results of surveillance. The DCT was carried out by pressing disks on to colonies and rehydrating in Petri plates and observing color change. RESULTS: The DCT differentiated 688 of 694 (sensitivity 99.1%) carbapenemase-producing isolates in 2.5-20 min: 630 with KPC, 51 with NDM, three with IMP, one with VIM, two with KPC and IMP, and one with NDM and OXA-181. The DCT failed to detect six OXA- 48-like enzyme-producing isolates, but the modified method using 96-well flat-bottom microplates with mineral oil cover detected all 29 OXA-48-like enzyme-producing isolates in 20-120 min. The DCT was negative for all 440 ertapenem-nonsusceptible, carbapenemase gene-negative isolates (specificity 100%). CONCLUSION: The procedure of DCT is simple and can differentiate isolates of Enterobacterales with KPC-, NDM-, IMP- and VIM-type carbapenemases rapidly, and the modified DCT can detect isolates with OXA-48-like enzymes rapidly.

Microbiome of Haemaphysalis longicornis Tick in Korea.

Ticks can transmit pathogenic bacteria, protozoa, and viruses to humans and animals. In this study, we investigated the microbiomes of Haemaphysalis longicornis according to sex and life stages. The Shannon index was significantly higher for nymphs than adult ticks. Principal coordinates analysis showed that the microbiome composition of female adult and male adult ticks were different. Notably, Coxiella-like bacterium (AB001519), known as a tick symbiont, was found in all nymphs and female adult ticks, but only one out of 4 male adult ticks had Coxiella-like bacterium (AB001519). In addition, Rickettsia rickettsii, Coxiella burnetii, and Anaplasma bovis were detected in this study.

Evaluation of Two Commercial Broth Microdilution Methods Using Different Interpretive Criteria for the Detection of Molecular Mechanisms of Acquired Azole and Echinocandin Resistance in Four Common Candida Species.

The abilities of the new Vitek 2 AST-YS08 (YS08) and Sensititre YeastOne (SYO) systems to detect the resistances of Candida isolates to azoles and echinocandins were evaluated. In total, 292 isolates, including 28 Candida albicans (6 Erg11 and 2 Fks mutants), 57 Candida parapsilosis (26 Erg11 mutants), 24 Candida tropicalis (10 Erg11 and 1 Fks mutants), and 183 Candida glabrata (39 Pdr1 and 13 Fks mutants) isolates, were tested. The categorical agreements (CAs) between the Clinical and Laboratory Standards Institute (CLSI) method and YS08 fluconazole MICs obtained using clinical breakpoints were 92.4% (C. albicans), 96.5% (C. parapsilosis), and 87.0% (C. tropicalis), and the CAs between the CLSI and SYO MICs were 92.3% (C. albicans), 77.2% (C. parapsilosis), 100% (C. tropicalis), and 98.9% (C. glabrata). For C. glabrata, the CAs with the CLSI micafungin MICs were 92.4% and 55.5% for the YS08 micafungin and caspofungin MICs, respectively; they were 100%, 95.6%, and 98.9% for the SYO micafungin, caspofungin, and anidulafungin MICs, respectively. YS08 does not provide fluconazole data for C. glabrata; the CA with the CLSI fluconazole MIC was 97.8% for the YS08 voriconazole MIC, using an epidemiological cutoff value (ECV) of 0.5 µg/ml. Increased CAs with the CLSI MIC were observed for the YS08 MIC using CLSI ECVs (for fluconazole and C. tropicalis, 100%; for micafungin and C. glabrata, 98.9%) and for the SYO MIC using method-specific ECVs (for fluconazole and C. parapsilosis, 91.2%; for caspofungin and C. glabrata, 98.9%). Therefore, the YS08 and SYO systems may have different abilities to detect mechanisms of azole and echinocandin resistance in four Candida species; the use of method-specific ECVs may improve the performance of both systems.

Respiratory Specimen Collection Booth for COVID-19 Test: Efficiency Based Newly Introduced Facility.

Hospitals need to find a safe and rapid method for respiratory specimen collection as the number of patients suspicious for coronavirus disease -2019 (COVID-19) rapidly grows. Applied with significant infection control and prevention measures, a respiratory specimen collection booth was newly designed. The new respiratory specimen collection booth not only increased COVID-19 testing cases but also decreased personal protective equipment consumption.

Use of Convalescent Plasma Therapy in Two COVID-19 Patients with Acute Respiratory Distress Syndrome in Korea.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 not yet has established its treatment, but convalescent plasma has been expected to increase survival rates as in the case with other emerging viral infections. We describe two cases of COVID-19 treated with convalescent plasma infusion. Both patients presented severe pneumonia with acute respiratory distress syndrome and showed a favorable outcome after the use of convalescent plasma in addition to systemic corticosteroid. To our knowledge, this is the first report of the use of convalescent plasma therapy for COVID-19 in Korea.

Performance evaluation of a new matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, ASTA MicroIDSys system, in bacterial identification against clinical isolates of anaerobic bacteria.

INTRODUCTION: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been introduced for bacterial identification. The ASTA MicroIDSys system (ASTA, Suwon, Korea) is a new MALDI-TOF MS system developed for species identification of microorganisms. We evaluated the performance of MicroIDSys against clinical isolates of anaerobic bacteria. MATERIAL AND METHODS: A total of 370 non-duplicated clinical isolates of anaerobic bacteria were tested in this study. Bacterial identification with MicroIDSys was performed with a direct smear method, and measured spectra were analyzed using respective software. The results of MicroIDSys were compared with the results of Bruker Biotyper and 16S rRNA sequencing. RESULTS: The overall agreement rates for the 370 clinical isolates (34 genera and 99 species) were 95.4% (353/370) at the genus level and 91.6% (n = 340) at the species level. Only 17 isolates were incorrectly identified at the genus level: five misidentifications and 12 unidentifications. The MicroIDSys system exhibited excellent performance in the identification of clinically relevant bacterial species. Most of the Bacteroides isolates (98.0%, 99/101) and all of the Clostridium difficile (100%, n = 11), Clostridium perfringens (100%, n = 10), Finegoldia magna (100%, n = 11), and Parvimonas micra (100%, n = 10) isolates were correctly identified at the species level. CONCLUSION: The MicroIDSys system proved useful in the identification of anaerobic bacteria, especially clinically relevant species. This system could be of use in clinical microbiology laboratories as a primary tool for identifying anaerobic bacteria.

Comparative Microbiome Analysis of Three Species of Laboratory-Reared Periplaneta Cockroaches.

Cockroaches inhabit various habitats, which will influence their microbiome. Although the microbiome can be influenced by the diet and environmental factors, it can also differ between species. Therefore, we conducted 16S rDNAtargeted high-throughput sequencing to evaluate the overall bacterial composition of the microbiomes of 3 cockroach species, Periplaneta americana, P. japonica, and P. fuliginosa, raised in laboratory for several generations under the same conditions. The experiments were conducted using male adult cockroaches. The number of operational taxonomic units (OTUs) was not significantly different among the 3 species. With regard to the Shannon and Pielou indexes, higher microbiome values were noted in P. americana than in P. japonica and P. fuliginosa. Microbiome composition was also evaluated, with endosymbionts accounting for over half of all OTUs in P. japonica and P. fuliginosa. Beta diversity analysis further showed that P. japonica and P. fuliginosa had similar microbiome composition, which differed from that of P. americana. However, we also identified that P. japonica and P. fuliginosa host distinct OTUs. Thus, although microbiome compositions may vary based on multiple conditions, it is possible to identify distinct microbiome compositions among different Periplaneta cockroach species, even when the individuals are reared under the same conditions.

Risk Factors for Elizabethkingia Acquisition and Clinical Characteristics of Patients, South Korea.

Elizabethkingia infections are difficult to treat because of intrinsic antimicrobial resistance, and their incidence has recently increased. We conducted a propensity score-matched case-control study during January 2016-June 2017 in South Korea and retrospectively studied data from patients who were culture positive for Elizabethkingia species during January 2009-June 2017. Furthermore, we conducted epidemiologic studies of the hospital environment and mosquitoes. The incidence of Elizabethkingia increased significantly, by 432.1%, for 2016-2017 over incidence for 2009-2015. Mechanical ventilation was associated with the acquisition of Elizabethkingia species. Because Elizabethkingia infection has a high case-fatality rate and is difficult to eliminate, intensive prevention of contamination is needed.

Two Novel Bacteriophages Improve Survival in Galleria mellonella Infection and Mouse Acute Pneumonia Models Infected with Extensively Drug-Resistant Pseudomonas aeruginosa.

Extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) is a life-threatening pathogen that causes serious global problems. Here, we investigated two novel P. aeruginosa bacteriophages (phages), Bϕ-R656 and Bϕ-R1836, in vitro, in silico, and in vivo to evaluate the potential of phage therapy to control XDR-PA clinical strains. Bϕ-R656 and Bϕ-R1836 belong to the Siphoviridae family and exhibited broad host ranges which could lyse 18 (64%) and 14 (50%) of the 28 XDR-PA strains. In addition, the two phages showed strong bacteriolytic activity against XDR-PA host strains from pneumonia patients. The whole genomes of Bϕ-R656 and Bϕ-R1836 have linear double-stranded DNA of 60,919 and 37,714 bp, respectively. The complete sequence of Bϕ-R656 had very low similarity to the previously discovered P. aeruginosa phages in GenBank, but phage Bϕ-R1836 exhibited 98% and 91% nucleotide similarity to Pseudomonas phages YMC12/01/R24 and PA1/KOR/2010, respectively. In the two in vivo infection models, treatment with Bϕ-R656 and Bϕ-R1836 enhanced the survival of Galleria mellonella larvae (50% and 60%, respectively) at 72 h postinfection and pneumonia-model mice (66% and 83%, respectively) at 12 days postinfection compared with untreated controls. Treatment with Bϕ-R656 or Bϕ-R1836 also significantly decreased the bacterial load in the lungs of the mouse pneumonia model (>6 log10 CFU and >4 log10 CFU, respectively) on day 5.IMPORTANCE In this study, two novel P. aeruginosa phages, Bϕ-R656 and Bϕ-R1836, were evaluated in vitro, in silico, and in vivo for therapeutic efficacy and safety as an alternative antibacterial agent to control XDR-PA strains collected from pneumonia patients. Both phages exhibited potent bacteriolytic activity and greatly improved survival in G. mellonella larva infection and a mouse acute pneumonia model. Based on these results, we strongly predict that these two new phages could be used as fast-acting and safe alternative biological weapons against XDR-PA infections.

Efficacy of bacteriophage treatment against carbapenem-resistant Acinetobacter baumannii in Galleria mellonella larvae and a mouse model of acute pneumonia.

BACKGROUND: Acinetobacter baumannii is an opportunistic pathogen that causes serious nosocomial infection in intensive care units. In particular, carbapenem-resistant A. baumannii (CRAB) strains have been increasing in the past decade, and they have caused major medical problems worldwide. In this study, a novel A. baumannii lytic phage, the YMC 13/03/R2096 ABA BP (phage Βϕ-R2096), which specifically causes the lysis of CRAB strains, was characterized in detail in vitro and in silico, and the in vivo effectiveness of phage therapy was evaluated using Galleria mellonella and a mouse model of acute pneumonia. RESULTS: The A. baumannii phage Βϕ-R2096 was isolated from sewage water using CRAB clinical strains selected from patients at a university hospital in South Korea. The complete genome of the phage Βϕ-R2096, which belongs to the Myoviridae family, was analyzed. Phage Βϕ-R2096 inhibited bacterial growth in a dose-dependent manner and exhibited high bacteriolytic activity at MOI = 10. In the evaluation of its therapeutic potential against CRAB clinical isolates using two in vivo models, phage Βϕ-R2096 increased the survival rates of both G. mellonella larvae (from 0 to 50% at 24 h) and mice (from 30% with MOI = 0.1 to 100% with MOI = 10 for 12 days) in post-infection of CRAB. In particular, phage Βϕ-R2096 strongly ameliorated histologic damage to infected lungs, with bacterial clearance in the lungs observed on day 3 postinfection in the mouse acute pneumonia model. Moreover, in vivo studies revealed no mortality or serious side effects in phage-treated groups. CONCLUSION: The results of this study strongly suggest that phage Βϕ-R2096, a novel A. baumannii lytic phage, could be an alternative antibacterial agent to control CRAB infections. This study is the first report to compare in vivo evaluations (G. mellonella larvae and a mouse acute pneumonia model) of the therapeutic efficacy of a phage against CRAB infections.

Chinese liver fluke Clonorchis sinensis infection changes the gut microbiome and increases probiotic Lactobacillus in mice.

Chinese liver fluke Clonorchis sinensis changes the host's immune system. Recently, it has been reported that helminths including C. sinensis can ameliorate immune-related diseases such as allergy. In addition, recent studies showed that helminth infection can alleviate immune-mediated disorders by altering the gut microbiome. However, changes in the gut microbiome due to C. sinensis have not been reported yet. In this study, changes in the gut microbiome of C57BL/6 mice infected with C. sinensis metacercariae were evaluated over time. Stool was analyzed by 16S rRNA amplicon analysis using high-throughput sequencing technology. There was no apparent difference in species richness and diversity between the infected and control groups. However, the composition of the microbiome was different between the infected and control groups at 20 days and 30 days post-infection, and the difference disappeared at 50 days post-infection. In particular, this microbiome alteration was associated with a change in the relative abundance of genus Lactobacillus and the probiotic Lactobacillus species that are known to have an immune-modulation role in immune-mediated diseases.