Comprehensive analysis of disinfectants on the horizontal transfer of antibiotic resistance genes.

The propagation of antimicrobial resistance (AMR) is constantly paralyzing our healthcare systems. In addition to the pressure of antibiotic selection, the roles of non-antibiotic compounds in disseminating antibiotic resistance genes (ARGs) are a matter of great concerns. This study aimed to explore the impact of different disinfectants on the horizontal transfer of ARGs and their underlying mechanisms. First, the effects of different kinds of disinfectants on the conjugative transfer of RP4-7 plasmid were evaluated. Results showed that quaternary ammonium salt, organic halogen, alcohol and guanidine disinfectants significantly facilitated the conjugative transfer. Conversely, heavy-metals, peroxides and phenols otherwise displayed an inhibitory effect. Furthermore, we deciphered the mechanism by which guanidine disinfectants promoted conjugation, which includes increased cell membrane permeability, over-production of ROS, enhanced SOS response, and altered expression of conjugative transfer-related genes. More critically, we also revealed that guanidine disinfectants promoted bacterial energy metabolism by enhancing the activity of electron transport chain (ETC) and proton force motive (PMF), thus promoting ATP synthesis and flagellum motility. Overall, our findings reveal the promotive effects of disinfectants on the transmission of ARGs and highlight the potential risks caused by the massive use of guanidine disinfectants, especially during the COVID-19 pandemic.

An insight overview on COVID-19 mRNA vaccines: Advantageous, pharmacology, mechanism of action, and prospective considerations.

The worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has urged scientists to present some novel vaccine platforms during this pandemic to provide a rather prolonged immunity against this respiratory viral infection. In spite of many campaigns formed against the administration of mRNA-based vaccines, those platforms were the most novel types, which helped us meet the global demand by developing protection against COVID-19 and reducing the development of severe forms of this respiratory viral infection. Some societies are worry about the COVID-19 mRNA vaccine administration and the potential risk of genetic integration of inoculated mRNA into the human genome. Although the efficacy and long-term safety of mRNA vaccines have not yet been fully clarified, obviously their application has switched the mortality and morbidity of the COVID-19 pandemic. This study describes the structural features and technologies used in producing of COVID-19 mRNA-based vaccines as the most influential factor in controlling this pandemic and a successful pattern for planning to produce other kind of genetic vaccines against infections or cancers.

Uncovering novel disinfection mechanisms of solar light/periodate system: The dominance of singlet oxygen and metabolomic insights

Disinfection plays an essential role in waterborne pathogen control and disease prevention, especially during the COVID-19 pandemic. Catalyst-free solar light/periodate (PI) system has recently presented great potential in water disinfection, whereas the in-depth chemical and microbiological mechanisms for efficient bacterial inactivation remain unclear. Our work delineated firstly the critical role of singlet oxygen, instead of reported hydroxyl radicals and superoxide radicals, in dominating bacterial inactivation by the PI/simulated sunlight (SSL) system. Multi-evidence demonstrated the prominent disinfection performance of this system for Staphylococcus aureus in terms of culturability (> 6 logs CFU), cellular integrity, and metabolic activity. Particularly, the excellent intracellular DNA removal (> 95%) indicated that PI/SSL system may function as a selective disinfection strategy to diminish bacterial culturability without damaging the cell membrane. The PI/SSL system could also effectively inhibit bacterial regrowth for > 5 days and horizontal gene transfer between E. coli genera. Nontargeted metabolomic analysis suggested that PI/SSL system inactivated bacteria by triggering the accumulation of intracellular reactive oxygen species and the depletion of reduced glutathione. Additionally, the PI/SSL system could accomplish simultaneous micropollutant removal and bacterial inactivation, suggesting its versatility in water decontamination. Overall, this study deciphers more comprehensive antibacterial mechanisms of this environmentally friendly disinfection system, facilitating the technical development and application of the selective disinfection strategy in environmental pathogen control. [Display omitted] • PI/SSL system selectively inactivates cells by targeting intracellular DNA first. • PI/SSL treatment inhibits bacterial regrowth and horizontal gene transfer potential. • The bactericidal effect of 1O 2 in PI/SSL system was proposed for the first time. • Metabolomics showed that ROS accumulation is one of the antibacterial mechanisms. • PI/SSL system holds great promise in decontamination of the actual water system. [ FROM AUTHOR]

IN VITRO TO IN VIVO: COMBATING MULTIDRUG-RESISTANT ENTEROBACTERIACAE IN THE AGE OF COVID-19

SESSION TITLE: COVID-19 Co-Infections SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/19/2022 12:45 pm - 1:45 pm INTRODUCTION: The COVID-19 pandemic has highlighted the emergence of multidrug-resistant bacterial pathogens. Here we present a case of the successful treatment of a COVID-19 superinfection with Citrobacter freundii, which produced both a Klebsiella pneumoniae carbapenemase (KPC) as well as a New Delhi Metallo-Beta-Lactamase (NDM-1). CASE PRESENTATION: A 53-year-old male without significant past medical history was admitted to the intensive care unit for acute hypoxemic respiratory failure due to COVID-19 pneumonia. His hospital course was complicated by progressive hypoxia requiring intubation and mechanical ventilation. Due to persistent fevers and increased respiratory secretions, he was placed on empiric antibiotic therapy including vancomycin, cefepime, and briefly meropenem. Blood cultures were periodically drawn and ultimately demonstrated no growth. However, a respiratory culture via bronchoalveolar lavage was positive for multidrug-resistant Citrobacter freundii. Susceptibilities showed high level of resistance to meropenem, Imipenem, Ceftazidime-Avibactam as well as Aztreonam. Molecular testing confirmed the presence of both KPC and NDM-1 β-lactamases. The patient was treated with a combination of Aztreonam 2g plus Ceftazidime-Avibactam 2.5g IV every eight hours via simultaneous infusion for fourteen days, resulting in clinical improvement and discharge to a rehabilitation facility. DISCUSSION: The emergence of carbapenem-resistant enterobacteria has been identified as a major clinical problem. The high rates and high mortality of carbapenem-resistant enterobacteria complicating the course of COVID patients during the pandemic highlighted the importance of this issue. Among the Enterobacteriaceae, β-lactam resistance is primarily caused by enzymatic degradation by β-lactamases. Two carbapenemase subclasses are especially problematic: KPC and NDM-1. Horizontal gene transfer and clonal expansion have enabled KPC and NDM-1 to spread worldwide. However, coexistence of these two resistant mechanisms within the same pathogen has rarely been reported. Recently, high stability, non-inferior fitness, and transferability among patients of KPC-2-NDM-1-CRKPs have been documented, raising further concerns about the risk for further spread and increasing rates [1]. Therapeutic options are limited. We used a combination of Ceftazidime/Avibactam plus Aztreonam for treatment, based on limited in vitro studies demonstrating a synergistic effect and superior clearance rather than either antibiotic alone or administered in sequence [2,3]. CONCLUSIONS: Superinfections with carbapenem-resistant enterobacteria have increased in the context of the COVID-19 pandemic and are likely to become more prevalent in our hospitals. Prompt recognition and appropriate therapeutic selection are paramount for treating these highly resistant organisms. Reference #1: Gao H, Liu Y, Wang R, Wang Q, Jin L, Wang H. The transferability and evolution of NDM-1 and KPC-2 co-producing Klebsiella pneumoniae from clinical settings. EBioMedicine. 2020 Jan;51:102599. doi: 10.1016/j.ebiom.2019.102599. Epub 2020 Jan 3. PMID: 31911273;PMCID: PMC6948161. Reference #2: Marshall S, Hujer AM, Rojas LJ, Papp-Wallace KM, Humphries RM, Spellberg B, Hujer KM, Marshall EK, Rudin SD, Perez F, Wilson BM, Wasserman RB, Chikowski L, Paterson DL, Vila AJ, van Duin D, Kreiswirth BN, Chambers HF, Fowler VG Jr, Jacobs MR, Pulse ME, Weiss WJ, Bonomo RA. Can Ceftazidime-Avibactam and Aztreonam Overcome β-Lactam Resistance Conferred by Metallo-β-Lactamases in Enterobacteriaceae? Antimicrob Agents Chemother. 2017 Mar 24;61(4):e02243-16. doi: 10.1128/AAC.02243-16. PMID: 28167541;PMCID: PMC5365724. Reference #3: Lodise TP, Smith NM, O'Donnell N, et al. Determining the optimal dosing of a novel combination regimen of ceftazidime/avibactam with aztreonam against NDM-1-producing Enterobacteriaceae using a hollow-fibre infection model. J Antimicrob Chemother 202 ;75(9): 2622-32 DISCLOSURES: No relevant relationships by wisam daoud No relevant relationships by Christopher Walker No relevant relationships by Amanda Westbrook No relevant relationships by Nicola Zetola

Mechanisms of Microbial Disinfectant Resistance

Disinfectants can effectively inhibit or kill microorganisms on the surface of objects and transmission media, which are widely used in food, hygiene, health, pandemic prevention and other fields. During the COVID-19 pandemic, the global use of disinfectants increased sharply, which played an important role in effectively preventing and controlling the spread of the virus and preventing the spread of the pandemic. However, improper use of disinfectants will reduce its effectiveness and even induce microbial resistance, which may increase the risk of infectious disease transmission. The disinfectant resistance gene of microorganism will also aggravate its pollution and transmission risk through vertical reproduction or horizontal transfer between the same or different species, which seriously threatens public health safety. At present, the wide emergence of antibiotic resistance gene (ARG) has attracted global attention to public health, but the understanding of disinfectant resistance is very limited. This paper reviews the research on microbial resistance to disinfectants in recent years, focusing on the mechanism of microbial resistance by forming biofilm, reducing cell membrane permeability, over expressing efflux pump, producing specific enzymes to eliminate or attenuate disinfectants, and changing action targets. The formation of strong biofilm can effectively prevent disinfectants from approaching microorganisms, reduce microbial sensitivity and improve resistance;the reduction of cell membrane permeability depends on the changes of membrane protein, phospholipid and lipopolysaccharide, which can reduce the entry of disinfectants into microbial cells;the overexpression of efflux pump system is conducive to microorganisms to discharge harmful substances in cells;the action of specific enzymes can degrade the effective components of disinfectants or improve microbial immunity;the change of target can reduce the combination of disinfectant and action site, so as to reduce the disinfection effect. In addition, aiming at the acquisition and transmission of microbial disinfectant resistance, the chromosome and plasmid mediated resistance genes as well as the relationship between microbial disinfectant resistance and antibiotic resistance in the environment were discussed. Disinfectant resistance genes can be transferred and transmitted by transformation, transduction or conjugation through mobile genetic elements such as plasmids and phages, which puts forward new requirements for scientific disinfection.

The Neighborhood of the Spike Gene Is a Hotspot for Modular Intertypic Homologous and Nonhomologous Recombination in Coronavirus Genomes.

Coronaviruses (CoVs) have very large RNA viral genomes with a distinct genomic architecture of core and accessory open reading frames (ORFs). It is of utmost importance to understand their patterns and limits of homologous and nonhomologous recombination, because such events may affect the emergence of novel CoV strains, alter their host range, infection rate, tissue tropism pathogenicity, and their ability to escape vaccination programs. Intratypic recombination among closely related CoVs of the same subgenus has often been reported; however, the patterns and limits of genomic exchange between more distantly related CoV lineages (intertypic recombination) need further investigation. Here, we report computational/evolutionary analyses that clearly demonstrate a substantial ability for CoVs of different subgenera to recombine. Furthermore, we show that CoVs can obtain-through nonhomologous recombination-accessory ORFs from core ORFs, exchange accessory ORFs with different CoV genera, with other viruses (i.e., toroviruses, influenza C/D, reoviruses, rotaviruses, astroviruses) and even with hosts. Intriguingly, most of these radical events result from double crossovers surrounding the Spike ORF, thus highlighting both the instability and mobile nature of this genomic region. Although many such events have often occurred during the evolution of various CoVs, the genomic architecture of the relatively young SARS-CoV/SARS-CoV-2 lineage so far appears to be stable.

Horizontal gene transfer and recombination analysis of SARS-CoV-2 genes helps discover its close relatives and shed light on its origin.

BACKGROUND: The SARS-CoV-2 pandemic is one of  the greatest  global medical and social challenges that have emerged in recent history. Human coronavirus strains discovered during previous SARS outbreaks have been hypothesized to pass from bats to humans using intermediate hosts, e.g. civets for SARS-CoV and camels for MERS-CoV. The discovery of an intermediate host of SARS-CoV-2 and the identification of specific mechanism of its emergence in humans are topics of primary evolutionary importance. In this study we investigate the evolutionary patterns of 11 main genes of SARS-CoV-2. Previous studies suggested that the genome of SARS-CoV-2 is highly similar to the horseshoe bat coronavirus RaTG13 for most of the genes and to some Malayan pangolin coronavirus (CoV) strains for the receptor binding (RB) domain of the spike protein. RESULTS: We provide a detailed list of statistically significant horizontal gene transfer and recombination events (both intergenic and intragenic) inferred for each of 11 main genes of the SARS-CoV-2 genome. Our analysis reveals that two continuous regions of genes S and N of SARS-CoV-2 may result from intragenic recombination between RaTG13 and Guangdong (GD) Pangolin CoVs. Statistically significant gene transfer-recombination events between RaTG13 and GD Pangolin CoV have been identified in region [1215-1425] of gene S and region [534-727] of gene N. Moreover, some statistically significant recombination events between the ancestors of SARS-CoV-2, RaTG13, GD Pangolin CoV and bat CoV ZC45-ZXC21 coronaviruses have been identified in genes ORF1ab, S, ORF3a, ORF7a, ORF8 and N. Furthermore, topology-based clustering of gene trees inferred for 25 CoV organisms revealed a three-way evolution of coronavirus genes, with gene phylogenies of ORF1ab, S and N forming the first cluster, gene phylogenies of ORF3a, E, M, ORF6, ORF7a, ORF7b and ORF8 forming the second cluster, and phylogeny of gene ORF10 forming the third cluster. CONCLUSIONS: The results of our horizontal gene transfer and recombination analysis suggest that SARS-CoV-2 could not only be a chimera virus resulting from recombination of the bat RaTG13 and Guangdong pangolin coronaviruses but also a close relative of the bat CoV ZC45 and ZXC21 strains. They also indicate that a GD pangolin may be an intermediate host of this dangerous virus.

A genetic element in the SARS-CoV-2 genome is shared with multiple insect species.

SARS-CoV-2 is a member of the subgenus Sarbecovirus and thus contains the genetic element s2m. We have extensively mined nucleotide data in GenBank in order to obtain a comprehensive list of s2m sequences both in the four virus families where s2m has previously been described and in other groups of organisms. Surprisingly, there seems to be a xenologue of s2m in a large number of insect species. The function of s2m is unknown, but our data show a very high degree of sequence conservation both in insects and in viruses and that the version of s2m found in SARS-CoV-2 has unique features, not seen in any other virus or insect strains.