[Carbapenemase Genes, Virulence Genes, and Molecular Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae Derived From Bloodstream Infections]. / è¡€æµæ„ŸæŸ“ç¢³é’éœ‰çƒ¯è€è¯è‚ºç‚Žå ‹é›·ä¼¯èŒçš„è€è¯åŸºå› å’Œæ¯’åŠ›åŸºå› åŠåˆ†å­æµè¡Œç— å­¦ç ”ç©¶.

Objective: To investigate the clinical characteristics and molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from patients with bloodstream infections in a large tertiary-care general hospital in Southwest China. Methods: A total of 131 strains of non-repeating CRKP were collected from the blood cultures of patients who had bloodstream infections in 2015-2019. The strains were identified by VITEK-2, a fully automated microbial analyzer, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The minimum inhibitory concentration (MIC) was determined by microbroth dilution method. The common carbapenemase resistant genes and virulence factors were identified by PCR. Homology analysis was performed by multilocus sequencing typing. Whole genome sequencing was performed to analyze the genomic characteristics of CRKP without carbapenemase. Results: The 131 strains of CRKP showed resistance to common antibiotics, except for polymyxin B (1.6% resistance rate) and tigacycline (8.0% resistance rate). A total of 105 (80.2%) CRKP strains carried the Klebsiella pneumoniae carbapenemase (KPC) resistance gene, 15 (11.4%) strains carried the New Delhi Metallo-ß-lactamase (NDM) gene, and 4 (3.1%) isolates carried both KPC and NDM genes. Sequence typing (ST) 11 (74.0%) was the dominant sequence type. High detection rates for mrkD (96.2%), fimH (98.5%), entB (100%), and other virulence genes were reported. One hypervirulent CRKP strain was detected. The seven strains of CRKP that did not produce carbapenemase were shown to carry ESBL or AmpC genes and had anomalies in membrane porins OMPK35 and OMPK36, according to whole genome sequencing. Conclusion: In a large-scale tertiary-care general hospital, CRKP mainly carries the KPC gene, has a high drug resistance rate to a variety of antibiotics, and possesses multiple virulence genes. Attention should be paid to CRKP strains with high virulence.

Virulent Klebsiella pneumoniae ST11 clone carrying blaKPC and blaNDM from patients with and without COVID-19 in Brazil.

AIMS: Investigated and compared the occurrence of virulence genes fimH, mrkD, irp2, entB, cps, rmpA, and wabG, resistance genes blaKPC and blaNDM, and the genetic variability and clonal relationship of 29 Klebsiella pneumoniae clinical isolates of patients with and without COVID-19, from a hospital in Brazil. METHODS AND RESULTS: All isolates were resistant to beta-lactams. The genes were investigated by PCR, and for molecular typing, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and MLST were used. The detection of blaNDM was greater (n = 23) when compared to that of blaKPC (n = 14). The virulence genes that most occurred were fimH, entB, cps, and wabG, which are responsible for adhesins, siderophore enterobactin, capsule, and lipopolysaccharides, respectively. Among the isolates, 21 distinct genetic profiles were found by ERIC-PCR, with multiclonal dissemination. Four isolates belonged to the ST11 clone. CONCLUSIONS: The occurrence of the ST11 is worrying as it is a high-risk clone involved in the dissemination of virulent strains throughout the world.

Klebsiella pneumoniae outer membrane vesicles induce strong IL-8 expression via NF-κB activation in normal pulmonary bronchial cells.

BACKGROUND: Outer membrane vesicles (OMVs) derived from bacteria are known to play a crucial role in the interactions between bacteria and their environment, as well as bacteria-bacteria and bacteria-host interactions.Specifically, OMVs derived from Klebsiella pneumoniae have been implicated in contributing to the pathogenesis of this bacterium.Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a global pathogen of great concern due to its heightened virulence compared to classical K. pneumoniae (cKp), and its ability to cause community-acquired infections, even in healthy individuals.The objective of this study was to investigate potential differences between hvKp-derived OMVs and cKp-derived OMVs in their interactions with microorganisms and host cells. METHODS: Four strains of K. pneumoniae were used to produce OMVs: hvKp strain NTUH-K2044 (K1, ST23), hvKp clinical strain AP8555, and two cKP clinical strains C19 and C250. To examine the morphology and size of the bacterial OMVs, transmission electron microscopy (TEM) was utilized. Additionally, dynamic light scattering (DLS) was used to analyze the size characterization of the OMVs.The normal pulmonary bronchial cell line HBE was exposed to OMVs derived from hvKp and cKP. Interleukin 8 (IL-8) messenger RNA (mRNA) expression was assessed using reverse transcription-polymerase chain reaction (RT-PCR), while IL-8 secretion was analyzed using enzyme-linked immunosorbent assay (ELISA).Furthermore, the activation of nuclear factor kappa B (NF-κB) was evaluated using both Western blotting and confocal microscopy. RESULTS: After purification, OMVs appeared as electron-dense particles with a uniform spherical morphology when observed through TEM.DLS analysis indicated that hvKp-derived OMVs from K2044 and AP8555 measured an average size of 116.87 ± 4.95 nm and 96.23 ± 2.16 nm, respectively, while cKP-derived OMVs from C19 and C250 measured an average size of 297.67 ± 26.3 nm and 325 ± 6.06 nm, respectively. The average diameter of hvKp-derived OMVs was smaller than that of cKP-derived OMVs.A total vesicular protein amount of 47.35 mg, 41.90 mg, 16.44 mg, and 12.65 mg was generated by hvKp-K2044, hvKp-AP8555, cKP-C19, and cKP-C250, respectively, obtained from 750 mL of culture supernatant. Both hvKp-derived OMVs and cKP-derived OMVs induced similar expression levels of IL-8 mRNA and protein. However, IL-8 expression was reduced when cells were exposed to BAY11-7028, an inhibitor of the NF-κB pathway.Western blotting and confocal microscopy revealed increased phosphorylation of p65 in cells exposed to OMVs. CONCLUSIONS: Klebsiella pneumoniae produces outer membrane vesicles (OMVs) that play a key role in microorganism-host interactions. HvKp, a hypervirulent strain of K. pneumoniae, generates more OMVs than cKP.The average size of OMVs derived from hvKp is smaller than that of cKP-derived OMVs.Despite these differences, both hvKp-derived and cKP-derived OMVs induce a similar level of expression of IL-8 mRNA and protein.OMVs secreted by K. pneumoniae stimulate the secretion of interleukin 8 by activating the nuclear factor NF-κB.

Clinical and microbiological characteristics of bloodstream infection caused by Klebsiella pneumoniae harboring rmpA in Japanese adults.

We investigated the clinical features of bloodstream infections (BSIs) caused by Klebsiella pneumoniae harboring rmpA and molecular characteristics of the bacteria. We retrospectively investigated adult patients with K. pneumoniae BSI from January 2010 to March 2021 at Nagasaki University Hospital. A matched case-control study in a 1:3 ratio was conducted to clarify the clinical and bacterial characteristics of BSI caused by rmpA-positive K. pneumoniae compared with those caused by rmpA-negative isolates. Antimicrobial susceptibility testing and multilocus sequence typing (MLST) were performed for rmpA-positive isolates. The rmpA was detected in 36 (13.4%) of the 268 isolates. Of these 36 isolates, 31 (86.1%) harbored iucA and 35 (97.2%) each possessed peg-344 and iroB; capsular types were identified as K1 in 9 (25.0%) and K2 in 10 isolates (27.8%). Contrarily, of the 108 rmpA-negative isolates, which were matched for case-control studies, 5 isolates (4.6%) harbored iucA and 1 (0.9%) each possessed peg-344 and iroB; 2 (1.9%) and 3 isolates (2.8%) had K1 and K2 capsular types, respectively. Among the rmpA-positive isolates, ST23/K1 (eight isolates) was the most frequent, followed by ST412/non-K1/K2 (seven isolates), ST86/K2 (five isolates), and ST268/non-K1/K2 (four isolates). In a multivariate analysis using clinical factors, liver abscess positively correlated with rmpA-positive isolates, whereas biliary tract infection and use of anticancer drugs negatively correlated with rmpA-positive isolates in patients with K. pneumoniae BSI. Considering the correlation between rmpA-positive isolates and clinical features, rmpA can be used as a marker for understanding the pathophysiology of K. pneumoniae BSI.

Occult colon cancer with liver abscess and pancreatitis as the first manifestations: A case report.

INTRODUCTION: Klebsiella pneumoniae-induced liver abscess (KP-PLA) is a common type of pyogenic liver abscess, severe acute pancreatitis (SAP) has high mortality, and poor prognosis in advanced colon cancer. There have been no report of SAP complicated with colon cancer after KP-PLA as so far. In this study, we reported a case of SAP secondary to KP-PLA with colon cancer for the first time, so as to provide reference for clinical diagnosis and treatment of these diseases. PATIENT CONCERNS AND DIAGNOSIS: A 64-year-old woman with a history of diabetes visited our hospital with abdominal pain for 5 + days. He was diagnosed with KP-PLA a month ago, which had not healed when he was admitted. He was diagnosed with SAP, and histological examination of colonic biopsy confirmed the diagnosis of moderately differentiated adenocarcinoma. INTERVENTIONS AND OUTCOMES: He was treated with intravenous antibiotics and underwent modified endoscopic mucosal resection under colonoscopy. We conducted a 2-month follow-up, and there was no recurrence of liver abscess and pancreatitis. CONCLUSION: Screening for intestinal tumors is necessary in patients with cryptogenic liver abscess, especially KP-PLA with diabetes.

Atividade in vitro de extratos e frações de Copernicia prunifera (Arecaceae) contra bactérias de importância clínica em saúde pública / In vitro activity of extracts and fractions of Copernicia prunifera (Arecaceae) against bacteria of clinical importance in public health / Actividad in vitro de extractos y fracciones de Copernicia prunifera (Arecaceae) frente a bacterias de importancia clínica en salud pública

Introdução: O aumento contínuo da resistência bacteriana aos antibióticos convencionais é um problema de importância global. Encontrar produtos como alternativas terapêuticas naturais é essencial. As plantas medicinais possuem uma composição química muito rica, que podem ser estruturalmente otimizadas e processadas em novos antimicrobianos. Objetivo: Avaliar o potencial antibacteriano frente a microrganismos humanos potencialmente patogênicos do extrato etanólico e frações de Copernicia prunifera. Metodologia: A triagem fitoquímica de plantas foi realizada usando métodos de precipitação e coloração e a atividade antibacteriana utilizando o método de difusão em disco e microdiluição em caldo contra cepas padronizadas de Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus. Resultados: A triagem fitoquímica revela a presença de taninos, flavonoides, esteroides, triterpernóides, saponinas e alcaloides. Os extratos etanólico e frações da casca do caule e folhas tiveram atividade inibitória contra S. aureus e K. pneumonie com zona de inibição que variou de 7,0±1,73 a 9,33±0,58 mm pelo método de difusão em disco. Pelo método de microdiluição em caldo os extratos foram satisfatórios somente contra K. pneumoniae (CIM = 125 a 1000 µg/mL) S. aureus, P. aeruginosa e E. coli se mostraram resistentes aos testes (CIM > 1000 µg/mL). Conclusão: Esses resultados fornecem uma base para futuras investigações em modelos in vivo, para que os compostos de C. prunifera possam ser aplicados no desenvolvimento de novos agentes antimicrobianos contra K. pneumoniae.

Introduction: The continuous increase in bacterial resistance to conventional antibiotics is a problem of global importance. Finding products as natural therapeutic alternatives is essential. Medicinal plants have a very rich chemical composition, which can be structurally optimized and processed into novel antimicrobials. Objective: To evaluate the antibacterial potential against potentially pathogenic human microorganisms of the ethanolic extract and fractions of Copernicia prunifera. Methodology: Phytochemical screening of plants was performed using precipitation and staining methods and antibacterial activity using the disk diffusion and broth microdilution method against standardized strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Results: Phytochemical screening reveals the presence of tannins, flavonoids, steroids, triterpernoids, saponins and alkaloids. The ethanolic extracts and fractions of stem bark and leaves had inhibitory activity against S. aureus and K. pneumonie with zone of inhibition ranging from 7.0±1.73 to 9.33±0.58 mm by disc diffusion method. By broth microdilution method the extracts were satisfactory only against K. pneumoniae (MIC = 125 to 1000 µg/mL) S. aureus, P. aeruginosa and E. coli were resistant to the tests (MIC > 1000 µg/mL). Conclusion: These results provide a basis for further investigation in in vivo models, so that compounds from C. prunifera can be applied in the development of new antimicrobial agents against K. pneumoniae.

Introducción: El continuo aumento de la resistencia bacteriana a los antibióticos convencionales es un problema de importancia mundial. Es esencial encontrar productos como alternativas terapéuticas naturales. Las plantas medicinales tienen una composición química muy rica, que puede optimizarse estructuralmente y transformarse en nuevos antimicrobianos. Objetivo: Evaluar el potencial antibacteriano frente a microorganismos humanos potencialmente patógenos del extracto etanólico y fracciones de Copernicia prunifera. Metodología: Se realizó el cribado fitoquímico de las plantas mediante los métodos de precipitación y tinción y la actividad antibacteriana mediante el método de difusión en disco y microdilución en caldo frente a cepas estandarizadas de Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa y Staphylococcus aureus. Resultados: El cribado fitoquímico revela la presencia de taninos, flavonoides, esteroides, triterpernoides, saponinas y alcaloides. Los extractos etanólicos y las fracciones de la corteza del tallo y las hojas presentaron actividad inhibitoria contra S. aureus y K. pneumonie con una zona de inhibición que osciló entre 7,0±1,73 y 9,33±0,58 mm por el método de difusión en disco. Por el método de microdilución en caldo, los extractos sólo fueron satisfactorios frente a K. pneumoniae (CMI = 125 a 1000 µg/mL). S. aureus, P. aeruginosa y E. coli fueron resistentes a las pruebas (CMI > 1000 µg/mL). Conclusiones: Estos resultados proporcionan una base para futuras investigaciones en modelos in vivo, de modo que los compuestos de C. prunifera puedan aplicarse en el desarrollo de nuevos agentes antimicrobianos contra K. pneumoniae.

In vitro activity of six biocides against carbapenemase-producing Klebsiella pneumoniae and presence of genes encoding efflux pumps / Actividad in vitro de seis biocidas frente a Klebsiella pneumoniae productora de carbapenemasa y presencia de genes codificantes de bombas de expulsión

Introduction: Acquisition of reduced susceptibility to biocides may contribute to the dissemination of high-risk (HR) clones of carbapenemase-producing Klebsiella pneumoniae (CP-Kp). The aim of this study was (a) to determinate the activity of biocides against CP-Kp, and (b) to analyse the relationship between biocide activity and the presence of efflux pumps. Methods: The minimal inhibitory concentrations (MICs) of 6 biocides (sodium hypochlorite, chlorhexidine digluconate, benzalkonium chloride, povidone-iodine, ethanol and triclosan) were determined in triplicate at 25°C and 37°C in Mueller-Hinton broth (MHB) and M9 minimum medium, against 17 CP-Kp isolates representing different clones (HR and no-HR), sequence-types (STs) and carbapenemases. Efflux pumps genes were detected by whole genome sequencing (MiSeq). Results: Median MICs were slightly higher at 37°C than at 25°C (p≤0.05), except for benzalkonium chloride, triclosan and ethanol. MIC medians were much higher in MHB than in M9, except for triclosan. No significant differences were observed in the median MICs, regarding the type of clone, ST or carbapenemase; cepA, acrAB, kpnEF and oqxAB genes were detected in all isolates, whereas qacE and qacA were not detected; smvAR, and qacΔE genes were detected in 94% and 47% of isolates, respectively. Conclusions: Triclosan, chlorhexidine digluconate, benzalkonium chloride and ethanol were the most active biocides. The activity of some biocides is affected by temperature and growth media, suggesting that standardised procedures for biocide susceptibility testing based on MIC determination are required. This activity, in terms of MICs, are not related to the type of clone, ST, carbapenemase or the presence of the efflux pump genes.(AU)

Introducción: La adquisición de sensibilidad reducida a los biocidas puede contribuir a la diseminación de clones de alto riesgo (HR) de Klebsiella pneumoniae productor de carbapenemasa (Kp-PC). El objetivo de este trabajo fue: (a) determinar la actividad de varios biocidas frente a Kp-PC, y (b) analizar la relación de dicha actividad con la presencia de genes codificantes de bombas de expulsión. Métodos: Las concentraciones mínimas inhibitorias (CMI) de 6 biocidas (hipoclorito de sodio, digluconato de clorhexidina, cloruro de benzalconio, povidona yodada, etanol y triclosán) se determinaron por triplicado a 25 y 37°C, tanto en caldo Mueller-Hinton (MHB) como en medio mínimo M9, frente a 17 aislados de Kp-PC representativos de diferentes clones (HR y no HR), secuenciotipos (ST) y carbapenemasas. Los genes de bombas de expulsión se detectaron mediante secuenciación masiva del genoma completo (MiSeq). Resultados: Las medianas de las CMI fueron ligeramente superiores a 37°C que a 25°C, excepto para cloruro de benzalconio, etanol y triclosán. Las medianas de las CMI fueron considerablemente superiores en MHB que en M9, excepto para triclosán; cepA, acrAB, kpnEF y oqxAB se detectaron en todos los aislados, mientras que qacE y qacA no se detectaron; smvAR y qacΔE se detectaron en el 94% y en el 47% de los aislados, respectivamente. Conclusiones: La actividad de algunos biocidas se afecta por la temperatura y el medio de crecimiento. Esta actividad, en términos de CMI, no se relaciona con el tipo de clon, ST, carbapenemasa, ni con la presencia de genes que codifican bombas de expulsión.(AU)

Remembrance of infections past.

Host-derived metabolite trains the microbiota to develop colonization resistance.

Emergence of polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae from an individual in the community with asymptomatic bacteriuria.

BACKGROUND: The heteroresistance of polymyxin B, a last-resort antibiotic used to treat many serious bacterial infections, may lead to antibiotic treatment failure. However, polymyxin B-heteroresistant isolates are rare in individuals living in the community. We report a polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae (hvKP) isolate from an individual in the community with asymptomatic bacteriuria. RESULTS: The NYTJ35 isolate had multiple virulence genes that encoded a mucoid phenotype regulator (rmpA), aerobactin (iucABCD-iutA), salmochelin (iroBCDN), yersiniabactin (irp1-2 and ybtAEPQSTUX), and a truncated rmpA2. Infection of galleria mellonella larvae indicated the isolate was hypervirulent. Antimicrobial susceptibility testing showed it was susceptible to all tested antibiotics except polymyxin B. The proportion of surviving bacteria was 1.2 × 10- 7 based on the population analysis profile (PAP) method, suggesting the presence of polymyxin B heteroresistance. The isolate was not hypermucoviscous, but it was a strong biofilm producer. It had capsular serotype K1 and belonged to sequence type 23 (ST23). The isolate also had the D150G substitution in phoQ, which is known to confer polymyxin B resistance. CONCLUSIONS: We identified the co-occurrence of hypervirulence and polymyxin B heteroresistance in a K. pneumoniae isolate from an individual with asymptomatic bacteriuria. We suggest the use of increased screening for hvKP in individuals living in the community.

Distribution, characterization, and antibiotic resistance of hypervirulent Klebsiella pneumoniae isolates in a Chinese population with asymptomatic bacteriuria.

BACKGROUND: Asymptomatic bacteriuria (ASB) frequently occurs among all ages and may develop into urinary tract infections (UTIs). Hypervirulent Klebsiella pneumoniae (hvKP) has become a new threat to human health. In our study, we aimed to investigate the epidemiological characteristics of hvKP in population with ASB. RESULTS: A total of 61 K. pneumoniae isolates were collected from 7530 urine samples between October and December 2020. The strains were sensitive to most of the antimicrobial agents tested, but a polymyxin resistant strain was found (MIC>16 µg/mL). Three serotypes were detected, including K1 (16.4%, 10/61), K5 (1.6%, 1/61) and K57 (3.2%, 2/61). Four strains (KPNY9, KPNY31, KPNY40, and KPNY42) carried a combination of two or more hypervirulent markers (peg-344, iroB, iucA, prmpA, and prmpA2), and their survival rates after Galleria mellonella infection were lower than those of the other strains (40.0 vs. 70.0%), suggesting that they were hvKP. These hvKP strains with lower biofilm forming ability than classical K. pneumoniae (0.2625 ± 0.0579 vs. 0.6686 ± 0.0661, P = 0.033) were identified as belonging to K2-ST65, K2-ST86, K57-ST592, and K2-ST5559 (a new ST type). KPNY31 (ST5559) shared a close genetic relationship with KPNY42 (ST86) and other ST86 isolates, which have been detected in both nosocomial and community-acquired infections. CONCLUSIONS: The hvKP with relatively weak biofilm formation was detected in a population with ASB, which was more likely to cause bacteremia and serious consequences. A novel sequence type (ST5559) hvKP derived from ST86 was found. Therefore, hvKP should be monitored in the population with ASB.

Investigation of Biofilm Virulence Genes Prevalence in Klebsiella pneumoniae Isolated from the Urinary Tract Infections.

Klebsiella pneumonia is a pathogen and an agent that causes hospital-acquired infections. Klebsiella pneumonia is the first and most common causative agent in community-acquired infections and urinary tract diseases. This study aimed to detect common genes, (i.e., fimA, mrkA, and mrkD) in the isolates of K. pneumoniae, isolated from urine specimens using the polymerase chain reaction (PCR) method. The isolates of K. pneumoniae were collected from urine specimens in health centers in Wasit Governorate, Iraq, and diagnosed using Analytical Profile Index 20Eand 16S rRNA techniques. The microtiter plate (MTP) method was used to detect biofilm formation. A total of 56 isolates were identified as K. pneumonia cases. The results led to the detection of biofilms; accordingly, all K. pneumoniae isolates showed biofilm production by MTP, however, at different levels. The PCR method was employed to detect biofilm genes and showed that 49 (87.5%), 26 (46.4%), and 30 (53.6%) of isolates carried fimH, mrkA, and mrkD, respectively. Furthermore, susceptibility tests for different antibiotics revealed that K. pneumoniae isolates were resistant to amoxicillin-clavulanic acid (n=11, 19.5%), ceftazidime (n=13, 22.4%), ofloxacin (n=16, 28.1%), and tobramycin (n=27, 48.4%). It was also found all K. pneumonia isolates were sensitive to polymyxin B (92.6%), imipenem (88.3%), meropenem (79.4%), and amikacin (60.5%).

Algal polysaccharide's potential to combat respiratory infections caused by Klebsiella pneumoniae and Serratia marcescens biofilms.

The growth of respiratory diseases, as witnessed through the SARS and COVID-19 outbreaks, and antimicrobial-resistance together pose a serious threat to humanity. One reason for antimicrobial resistance is formation of bacterial biofilms. In this study the sulphated polysaccharides from green algae Chlamydomonas reinhardtii (Cr-SPs) is tested for its antibacterial and antibiofilm potential against Klebsiella pneumoniae and Serratia marcescens. Agar cup assay clearly indicated the antibacterial potential of Cr-SPs. Minimum inhibitory concentration (MIC50) of Cr-SPs against Klebsiella pneumoniae was found to be 850 µg/ml, and it is 800 µg/ml in Serratia marcescens. Time-kill and colony-forming ability assays suggest the concentration-dependent bactericidal potential of Cr-SPs. Cr-SPs showed 74-100% decrease in biofilm formation in a concentration-dependent manner by modifying the cell surface hydrophobic properties of these bacteria. Cr-SPs have also distorted preformed-biofilms by their ability to interact and destroy the extra polymeric substance and eDNA of the matured biofilm. Scanning electron microscopy analysis showed that Cr-SPs effectively altered the morphology of these bacterial cells and distorted the bacterial biofilms. Furthermore reduced protease, urease and prodigiosin pigment production suggest that Cr-SPs interferes the quorum sensing mechanism in these bacteria. The current study paves way towards developing Cr-SPs as a control strategy for treatment of respiratory tract infections.

In silico characterization, docking, and simulations to understand host-pathogen interactions in an effort to enhance crop production in date palms.

Food safety remains a significant challenge despite the growth and development in agricultural research and the advent of modern biotechnological and agricultural tools. Though the agriculturist struggles to aid the growing population's needs, many pathogen-based plant diseases by their direct impact on cell division and tissue development have led to the loss of tons of food crops every year. Though there are many conventional and traditional methods to overcome this issue, the amount and time spend are huge. Scientists have developed systems biology tools to study the root cause of the problem and rectify it. Host-pathogen protein interactions (HPIs) have a promising role in identifying the pathogens' strategy to conquer the host organism. In this paper, the interactions between the host Rhynchophorus ferrugineus (an invasive wood-boring pest that destroys palm) and the pathogens Proteus mirabilis, Serratia marcescens, and Klebsiella pneumoniae are comprehensively studied using protein-protein interactions, molecular docking, and followed by 200 ns molecular dynamic simulations. This study elucidates the structural and functional basis of these proteins leading towards better plant health, production, and reliability.

Novel colistin-EDTA combination for successful eradication of colistin-resistant Klebsiella pneumoniae catheter-related biofilm infections.

Development of an effective therapy to overcome colistin resistance in Klebsiella pneumoniae, a common pathogen causing catheter-related biofilm infections in vascular catheters, has become a serious therapeutic challenge that must be addressed urgently. Although colistin and EDTA have successful roles for eradicating biofilms, no in vitro and in vivo studies have investigated their efficacy in catheter-related biofilm infections of colistin-resistant K. pneumoniae. In this study, colistin resistance was significantly reversed in both planktonic and mature biofilms of colistin-resistant K. pneumoniae by a combination of colistin (0.25-1 µg/ml) with EDTA (12 mg/ml). This novel colistin-EDTA combination was also demonstrated to have potent efficacy in eradicating colistin-resistant K. pneumoniae catheter-related biofilm infections, and eliminating the risk of recurrence in vivo. Furthermore, this study revealed significant therapeutic efficacy of colistin-EDTA combination in reducing bacterial load in internal organs, lowering serum creatinine, and protecting treated mice from mortality. Altered in vivo expression of different virulence genes indicate bacterial adaptive responses to survive in hostile environments under different treatments. According to these data discovered in this study, a novel colistin-EDTA combination provides favorable efficacy and safety for successful eradication of colistin-resistant K. pneumonia catheter-related biofilm infections.

Anthocyanin Extract from Purple Sweet Potato Exacerbate Mitophagy to Ameliorate Pyroptosis in Klebsiella pneumoniae Infection.

Given the rise of morbidity and mortality caused by Klebsiella pneumoniae (KP), the increasing number of strains resistant to antibiotics, and the emergence of hypervirulent Klebsiella pneumonia, treatment of KP infection becomes difficult; thus, novel drugs are necessary for treatment. Anthocyanins, or natural flavonoids, have an extensive effect against bacterial infection. However, few studies on anti-KP are identified. Here, we evaluated the therapeutic effect of purple sweet potato anthocyanins (PSPAs) on KP, containing 98.7% delphinidin 3-sambubioside. Results showed that KP-infected mice after PSPAs treatment manifested decreased mortality, weakened lung injury, dampened inflammatory responses, and reduced bacterial systemic dissemination in vivo. In Vitro, PSPAs significantly suppressed pyroptosis and restricted NLRP3 inflammasome activation in alveolar macrophages infected with KP. As for the mechanism, PSPAs promote mitophagy by recruiting Parkin to the mitochondria. PSPAs-conferred mitophagy increased mitochondrial membrane potential and decreased mitochondrial reactive oxygen species and mitochondrial DNA, resulting in impaired NLRP3 inflammasome activation. In addition, the promotion of mitophagy by PSPAs required the Nrf2 signaling pathway. Collectively, these findings suggest that PSPAs are a potential option for the treatment of KP infection.

Emergence of Tigecycline Nonsusceptible and IMP-4 Carbapenemase-Producing K2-ST65 Hypervirulent Klebsiella pneumoniae in China.

Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) poses a significant public health challenge worldwide, but research on IMP-producing CR-hvKP and its tigecycline resistance is extremely scarce. We report herein the recovery of two IMP-4-producing, capsular serotype K2, sequence type 65 (K2-ST65), hypervirulent K. pneumoniae isolates (C1672 and C2051), which caused severe and fatal infections in ICU patients, after retrospectively screening 3,285 carbapenem-resistant K. pneumoniae isolates from 26 provinces in China. Notably, C2051 also demonstrated tigecycline nonsusceptibility, mediated by a frameshift mutation in the TetR/AcrR family transcriptional regulator. Both strains harbored blaIMP-4 and critical plasmid-borne virulence genes (rmpA/rmpA2, iucA, and iroN) and demonstrated high virulence in Galleria mellonella, indicating CR-hvKP. The blaIMP-4 gene was located on the IncU- and IncN-type plasmids, which showed high stability in C1672 and C2051 after serial passage for 5 days, with retention rates of 87% and 93.7%, respectively. No significant differences in growth rates were observed among the parental strains and the corresponding resistance plasmid-cured mutants (P = 0.5273), suggesting that strains carrying the blaIMP and virulence plasmids have the potential to exist for a long time without compromising fitness. The genetic environments of the blaIMP-4 gene in both strains were similar, and it has been inferred that the genetic regions of blaIMP-4 were inserted into different backbones. Several conjugal transfer genes, such as traO, traE, traN, and traBCD, were identified in the blaIMP-4-bearing plasmid of C2051, suggesting a higher ability for plasmid transmission. The convergence of IMP carbapenemase and tigecycline nonsusceptibility in a classic hypervirulent K. pneumoniae lineage highlights the need to enhance clinical awareness and epidemiologic surveillance. IMPORTANCE To date, research on IMP-producing CR-hvKP is extremely scarce. Only one case of urinary tract infection caused by an IMP-6-producing K1-ST23 hypervirulent K. pneumoniae isolate in Japan was recorded, with a limited description of clinical information and genomic features. None of the published studies examined the virulence of the reported strains or the stability and fitness of resistance plasmids or presented a phylogenetic analysis. This dearth of data is notable because CR-hvKP infections are increasingly identified, but critical characteristics of the emerging resistance mediated by IMP carbapenemases in CR-hvKP remain unknown. Here, we report the emergence of two IMP-4 carbapenemase-producing K2-ST65 hypervirulent K. pneumoniae isolates that caused severe and fatal infections in clinical settings in China. Notably, one of them also demonstrated tigecycline nonsusceptibility. These strains carrying blaIMP and virulence plasmids had the potential to exist for a long time without compromising their fitness, highlighting the urgent need to enhance clinical awareness and epidemiologic surveillance to prevent their dissemination.

Effect of 4-Hexylresorcinol on the Efficiency of Antibiotic Treatment of Experimental Sepsis Caused by Antibiotic-Resistant Klebsiella pneumoniae Strain in Mice.

High efficiency of a combined preparation including synergistic polymyxin B and 4-hexylresorcinol was shown for treatment of experimental sepsis caused by an antibiotic-resistant highly virulent hypermucoid Klebsiella pneumoniae strain KPM9Pmr in mice. Complex therapy with polymyxin B (1 mg/kg) and 4-hexylresorcinol (30 mg/kg) led to cure in 80%; in 20% of these mice, no bacterial cells were found. After treatment with polymyxin B alone, only 50% animals survived and all of them contained bacterial cells. Comparative analysis of the results of monotherapy and combined treatment indicates that 4-hexylresorcinol not only increases the efficiency of antibiotic, but also minimizes persistence of the infection agent and therefore, the risk of development of antibiotic resistance.

The face of hypervirulent Klebsiella pneumoniae isolated from clinical samples of two Iranian teaching hospitals.

Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a pathogen of global concern. In this study, both phenotypic and genotypic tests were used to detect hvKp. Antimicrobial resistance profiles and clonal relatedness of clinical isolates were also determined. We found that 34.2% (163/477) of the isolates were tellurite resistant, and among them 102 hvKp isolates detected with iucA or iutA or peg-344 as molecular markers. The blaSHV (80.4%), followed by blaCTX-M-15 (76.5%) and blaTEM (67.6%), blaOXA-48 (53.9%), and blaNDM-1 (32.3%) were detected, while blaKPC-1 was not present in any hvKp isolates. It was found that the majority of hvKp isolates belonged to capsular serotype K20 and ompK36 group C, which is related to clonal group (CG) 23 (e.g. ST23). A high percentage of multidrug-resistant hvKp (76.6%) and high resistance to imipenem (67%) indicated a serious problem that should be addressed in the clinical setting.