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Abstract Background This study investigated the factors influencing the prognosis of children with steroid-resistant nephrotic syndrome (SRNS) in patients from the Guangxi region. Methods We retrospectively analyzed clinical and pathological data of 279 patients with SRNS from six tertiary hospitals in Guangxi. Clinical data were compared between initial (I-SRNS) and secondary (S-SRNS) steroid resistance subgroups and Cox regression analysis was used to determine risk factors for chronic kidney disease (CKD) and CKD stage 5 (CKD5) in patients with SRNS. Results The median age of onset was 54 months. Thirty-three patients had extra-kidney manifestations. Fifty-two, 24, 57, 33, and 41 patients had hypertension, acute kidney injury, vitamin D deficiency, high intraocular pressure, and dwarfism, respectively. One hundred eighty-two and 92 patients had I-SRNS and S-SRNS, respectively. There were significant differences in sex, ethnicity, family history, incidence of hematuria, clinical classification, efficacy of immune agents, and prognosis between groups (P

This study aimed to discuss the pathogenic hereditary factors of children with steroid-resistant nephrotic syndrome (SRNS) in Guangxi, China. We recruited 89 patients with SRNS or infantile NS from five major pediatric nephrology centers in Guangxi, and conducted a retrospective analysis of clinical data. Whole-exome sequencing analysis was also performed on all patients. The risk of progression to chronic kidney disease (CKD) was assessed using the Kaplan-Meier method and Cox proportional hazards model. The study included 69 male and 20 female participants from 86 distinct families, with the median age of disease onset being 48 months (interquartile range: 24-93). Overall, 24.7% had a family history of SRNS, whereas 13.5% exhibited extra-kidney manifestations. We identified disease-causing variants in 24.7% (22/89) of patients across eight screened genes. The most frequently detected variant was found in COL4A5, followed by NPHS2 (5.6%), NPHS1 (2.2%), PAX2 (2.2%), WT1 (1.1%), LMX1B (1.1%), NUP105 (1.1%), and COL4A6 (1.1%). Twelve of the 26 pathogenic variants were determined to be de novo. Based on gene detection results, pathogenic variants were categorized into two groups: identified and unidentified variants. The identified variant group demonstrated a significant association with positive family history, steroid resistant-style, and response to immune therapy (P

ABSTRACT Hypervirulent Klebsiella pneumoniae with capsular polysaccharides (CPSs) causes severe nosocomial- and community-acquired infections. Phage-derived depolymerases can degrade CPSs from K. pneumoniae to attenuate bacterial virulence, but their antimicrobial mechanisms and clinical potential are not well understood. In the present study, Klebsiella phage GH-K3-derived depolymerase Depo32 (encoded by gene gp32) was identified to exhibit high efficiency in specifically degrading the CPSs of K2 serotype K. pneumoniae. The cryo-electron microscopy structure of trimeric Depo32 at a resolution up to 2.32 Å revealed potential catalytic centers in the cleft of each of the two adjacent subunits. K. pneumoniae subjected to Depo32 became more sensitive to phagocytosis by RAW264.7 cells and activated the cells by the mitogen-activated protein kinase signaling pathway. In addition, intranasal inoculation with Depo32 (a single dose of 200 µg, 20 µg daily for 3 days, or in combination with gentamicin) rescued all C57BL/6J mice infected with a lethal dose of K. pneumoniae K7 without interference from its neutralizing antibody. In summary, this work elaborates on the mechanism by which Depo32 targets the degradation of K2 serotype CPSs and its potential as an antivirulence agent. IMPORTANCE Depolymerases specific to more than 20 serotypes of Klebsiella spp. have been identified, but most studies only evaluated the single-dose treatment of depolymerases with relatively simple clinical evaluation indices and did not reveal the anti-infection mechanism of these depolymerases in depth. On the basis of determining the biological characteristics, the structure of Depo32 was analyzed by cryo-electron microscopy, and the potential active center was further identified. In addition, the effects of Depo32 on macrophage phagocytosis, signaling pathway activation, and serum killing were revealed, and the efficacy of the depolymerase (single treatment, multiple treatments, or in combination with gentamicin) against acute pneumonia caused by Klebsiella pneumoniae was evaluated. Moreover, the roles of the active sites of Depo32 were also elucidated in the in vitro and in vivo studies. Therefore, through structural biology, cell biology, and in vivo experiments, this study demonstrated the mechanism by which Depo32 targets K2 serotype K. pneumoniae infection.

Citrobacter braakii is an opportunistic pathogen that induces aquatic infections in fish and turtles. In this study, a bacteriophage that infects C. braakii, named vB_CbrM_HP1, was isolated from sewage. This phage belongs to Myoviridae family, Ounavirinae subfamily, Mooglevirus genus. We also used the phage to treat crucian carp infection caused by C. braakii for the first time. vB_CbrM_HP1 was relatively stable at temperatures ranging from 4 to 60°C and pH values ranging from 3 to 11 but float slightly. When the multiplicities of infection (MOI) was 0.0001, the titer reached a maximum of 4.20 × 1010 PFU/ml. As revealed from the results of whole genomic sequence analysis, the total length of vB_CbrM_HP1 was 89335 bp, encoding 135 ORFs, 9 of which were

Klebsiella pneumoniae (K. pneumoniae) is an important nosocomial and community acquired opportunistic pathogen which causes various infections. The emergence of multi-drug resistant (MDR) K. pneumoniae and carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP) has brought more severe challenge to the treatment of K. pneumoniae infection. In this study, a novel bacteriophage that specifically infects K. pneumoniae was isolated and named as vB_KpnM_P-KP2 (abbreviated as P-KP2). The biological characteristics of P-KP2 and the bioinformatics of its genome were analyzed, and then the therapeutic effect of P-KP2 was tested by animal experiments. P-KP2 presents high lysis efficiency in vitro. The genome of P-KP2 shows homology with nine phages which belong to “KP15 virus” family and its genome comprises 172,138 bp and 264 ORFs. Besides, P-KP2 was comparable to gentamicin in the treatment of lethal pneumonia caused by K. pneumoniae W-KP2 (K47 serotype). Furthermore, the combined treatment of P-KP2 and gentamicin completely rescued the infected mice. Therefore, this study not only introduces a new member to the phage therapeutic library, but also serves as a reference for other phage-antibiotic combinations to combat MDR pathogens.

Bovine mastitis, an inflammatory disease that occurs frequently in early lactation or the dry period, is primarily caused by bacterial infections. There is growing evidence that Aerococcus viridans (A. viridans) is becoming an important cause of bovine mastitis. The treatment of bovine mastitis is primarily based on antibiotics, which not only leads to a large economic burden but also the development of antibiotic resistance. On the other hand, bacteriophages present a promising alternative treatment strategy. The object of this study was to evaluate the potential of a previously isolated A. viridans phage vB_AviM_AVP (AVP) as an anti-mastitis agent in an experimental A. viridans-induced murine mastitis model. A. viridans N14 was isolated from the milk of clinical bovine mastitis and used to establish a mastitis model in mice. We demonstrated that administration of phage AVP significantly reduced colony formation by A. viridans and alleviated damage to breast tissue. In addition, reduced inflammation was indicated by decreased levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and myeloperoxidase (MPO) activity in the phage-treated group compared to those in the phosphate buffered saline (PBS)-treated group. To the best of our knowledge, this report is the first to show the potential use of phages as a treatment for A. viridans-induced mastitis.

Yersinia enterocolitica is generally considered an important food-borne pathogen worldwide, especially in the European Union. A lytic Yersinia phage X1 (Viruses; dsDNA viruses, no RNA stage; Caudovirales; and Myoviridae) was isolated. Phage X1 showed a broad host range and could effectively lyse 27/51 Y. enterocolitica strains covering various serotypes that cause yersiniosis in humans and animals (such as serotype O3 and serotype O8). The genome of this phage was sequenced and analyzed. No toxin, antibiotic-resistance or lysogeny related modules were found in the genome of phage X1. Studies of phage stability confirmed that X1 had a high tolerance toward a broad range of temperatures (4–60°C) and pH values (4–11) for 1 h. The ability to resist harsh acidic conditions and enzymatic degradation in vitro demonstrated that phage X1 is suitable for oral administration, and in particular, that this phage can pass the stomach barrier and efficiently reach the intestine in vivo without losing infectious ability. The potential of this phage against Y. enterocolitica infection in vitro was studied. In animal experiments, a single oral administration of phage X1 at 6 h post infection was sufficient to eliminate Y. enterocolitica in 33.3% of mice (15/45). In addition, the number of Y. enterocolitica strains in the mice was also dramatically reduced to approximately 103 CFU/g after 18 h compared with 107 CFU/g in the mice without phage treatment. Treatment with phage X1 showed significant improvement by intestinal histopathologic observations. Moreover, proinflammatory cytokine levels (IL-6, TNF-α, and IL-1β) were significantly reduced (P < 0.05). These results indicate that phage X1 is a promising candidate to control infection by Y. enterocolitica in vivo.

Klebsiella pneumoniae, especially hypervirulent K. pneumoniae (hvKP), is a common opportunistic pathogen that often causes hospital- and community-acquired infections. Capsular polysaccharide (CPS) is an important virulence factor of K. pneumoniae. Some phages encode depolymerases that can recognize and degrade bacterial polysaccharides. In this study, the lytic bacteriophage vB_KpnP_ZK1 (abbreviated as ZK1) was isolated using serotype K1 hvKP as the host. Although amino acid sequence BLAST analysis indicated that the tail fiber protein Depo16 of phage ZK1 showed no significant similarity to any reported phage depolymerases, it displayed enzymatic activities that are characteristic of phage depolymerases. After expression and puri fication, Depo16 could efficiently remove the capsular polysaccharide layer that surrounds the surface of serotype K1 K. pneumoniae. Although no bactericidal activity was detected, Depo16 makes serotype K1 K. pneumoniae sensitive to peritoneal macrophages (PMs). In addition, in a mouse bacteremia model of serotype K1 K. pneumoniae, 25 µg of Depo16 was effective in significantly prolonging survival. Depo16 treatment can reduce the bacterial load in blood and major tissues and alleviate tissue damage in mice. This indicates that the putative depolymerase Depo16 is a potential antibacterial agent against serotype K1 K. pneumoniae infections. IMPORTANCE Klebsiella pneumoniae often causes hospital-acquired infections and community-acquired infections. Capsular polysaccharide (CPS) is one of the crucial virulence factors of K. pneumoniae. K1 and K2 capsular-type K. pneumoniae strains are the most prevalent serotypes of hypervirulent K. pneumoniae (hvKP). In this study, a novel K. pneumoniae phage named vB_KpnP_ZK1 was isolated, and its putative depolymerase Depo16 showed low homology with other reported phage depolymerases. Depo16 can specifically degrade the K. pneumoniae K1 capsule making this serotype sensitive to peritoneal macrophages. More importantly, Depo16 showed a significant therapeutic effect in a mouse bacteremia model caused by serotype K1 K. pneumoniae. Thus, Depo16 is a potential antibacterial agent to combat serotype K1 K. pneumoniae infections. [ABSTRACT FROM AUTHOR]

Salmonella enterica subspecies enterica serovar abortus equi (S. abortus equi) is a frequently reported pathogen causing abortion in mares. In this study, the preventive and therapeutic effects of phage PIZ SAE-01E2 against S. abortus equi in a mouse model of abortion was investigated. Phage PIZ SAE-01E2 was stable at different temperatures (4 ~ 70 °C) and pH values (4 ~ 10) and could lyse the majority of the tested Salmonella strains (25/28) of serotype O:4 and O:9. There is no lysogenic, toxin or antibiotic-resistant related gene in the genome of PIZ SAE-01E2. All of these characteristics indicated PIZ SAE-01E2 has potential for phage therapy. In in vivo experiments, 2 x 103 CFU/mouse of S. abortus equi ATCC 9842 was sufficient to lead to murine abortion (gestational day 14.5) within 48 h. A single dose of intraperitoneal inoculation of PIZ SAE-01E2 (108 PFU/mouse, MOI = 105) 1 h before or after S. abortus equi challenge provided effective protection to all pregnant mice (10/10). The bacterial loads in the placenta and uterus of the infected mice were both significantly decreased (< 102 CFU/g) after 24 h treatment with phage PIZ SAE-01E2 compared to that of control group (> 106 CFU/g). In addition, the levels of inflammatory cytokines in the placenta and blood of the mice in the phage administration groups were significantly reduced (P < 0.05) compared to that of the control group. Altogether, this indicated that PIZ SAE-01E2 showed potential to block abortions induced by S. abortus equi in vivo. [ABSTRACT FROM AUTHOR]