Isolation and characterization of a potentially novel Siphoviridae phage (vB_SsapS-104) with lytic activity against Staphylococcus saprophyticus isolated from urinary tract infection

Isolation, characterization, and genomic analysis of three novel Herelleviridae family lytic bacteriophages against uropathogenic isolates of Staphylococcus saprophyticus

BACKGROUND

Staphylococcus saprophyticus (S. saprophyticus) is the second most prevalent etiological agent of urinary tract infections (UTIs) in young women. However, there is a paucity of data regarding its bacteriophage (phage). Therefore, this study was conducted to isolate and identify new lytic phages from municipal wastewater with the objective of increasing knowledge about phages and their genomes.

METHODS

A total of 11 clinical isolates of S. saprophyticus and 30 wastewater samples were used to isolate three lytic phages (vB_SsapH-Golestan-100, vB_SsapH-Golestan101-M, and vB_SsapH-Golestan-105-M). The morphology, behavioral characteristics, and complete DNA genomes of these phages were analyzed.

RESULTS

The microscopic images of the phages revealed that the sizes of their heads and tail lengths fell within the ranges of 90-111 nm and 234-266 nm, respectively. All phages exhibited high adsorption rates (99.5% in 15 min) and burst sizes (150-210 PFU per infected cell), with a potential for a narrow host range. Genomic analysis of Staphylococcus phages indicated a size of 136,433 base pairs (bp) with a guanine-cytosine (GC) content of 33.7% and 192 open reading frames (ORFs) for vB_SsapH-Golestan-100, 144,081 bp with a GC content of 29.6% and 205 ORFs for vB_SsapH-Golestan101-M, and 142,199 bp with a GC content of 30.6% and 203 ORFs for vB_SsapH-Golestan-105-M. A bioinformatics analysis indicated that all three phages belong to the Twortvirinae subfamily of Herelleviridae. Among the three phages, vB_SsapH-Golestan-100 exhibited the least similarity to previously known phages, with less than 21% similarity with its closest counterparts in genomic databases.

CONCLUSIONS

This study identified new phages that have the ability to destroy a broad range of S. saprophyticus isolates and may potentially be classified as a new genus and species within the Herelleviridae family in future studies.

Genomic and proteomic characterization of four novel Schitoviridae family phages targeting uropathogenic Escherichia coli strain

BACKGROUND

Escherichia coli-associated urinary tract infections (UTIs) are among the most prevalent bacterial infections in humans. Typically, antibiotic medication is used to treat UTIs, but over the time, growth of multidrug resistance among these bacteria has created a global public health issue that necessitates other treatment modalities, such as phage therapy.

METHODS

The UPEC strain PSU-5266 (UE-17) was isolated from human urine samples, while phages were obtained from wastewater. These phages were characterized through host range analysis, stability studies, adsorption assays, and electron microscopy. Additionally, genomic, phylogenetic, and proteomic analyses were conducted to provide further insights.

RESULTS

The current study describes the isolation and characterization of four Escherichia coli phages designated as UE-S5a, UE-S5b, UE-M3 and UE-M6. Bactericidal assays depicted that all bacteriophages exhibited a strong lytic ability against uropathogenic E. coli (UPEC) strain PSU-5266 (UE-17). The phages displayed a broad host range (31-41%) among 104 tested isolates and adsorption rate of 15-20 min. They were stable within pH range of 5-11 and temperature range of 4 to 55 °C. Electron microscopy showed that all phages have icosahedral heads (70-74 nm) and short non-contractile tails, thus exhibiting a podovirus morphology. Sequencing results showed that they have linear double stranded DNA, genome of 73 to 76 kb in length, with GC content of 42% and short direct terminal repeats. Their genomes contain 84-88 predicted genes with putative functions predicted to 42-48% of gene products. The phylogenetic and comparative genomic analysis results depicted that these phages, sharing > 98% sequence similarity, are new members of genus Gamaleyavirus of subfamily Enquatrovirinae, in the Schitoviridae family. Mass spectrometric analysis of purified phage particles identified 44-56 phage particle-associated proteins (PPAPs) belonging to various functional groups such as lysis proteins, structural proteins, DNA packaging related proteins, and proteins involved in replication, metabolism and regulation. In addition, no genes encoding virulence factors, antibiotic resistance or lysogeny factors were identified.

CONCLUSION

The overall findings suggest that these bacteriophages are potential candidates for phage therapy in treating UTIs caused by UPEC strains.

Coagulase-Negative Staphylococci phages panorama: Genomic diversity and in vitro studies for a therapeutic use

Coagulase-negative staphylococci (CoNS) are commensal bacteria of the human skin and mucosal membranes. The incidence of nosocomial infections caused by these species is on the rise, leading to a potential increase in antibiotic tolerance and resistance. Phages are emerging as a promising alternative to combat CoNS infections. Scientists are isolating phages infecting CoNS with a particular interest in S. epidermidis. This review compiles and analyses CoNS phages for several parameters including source, geographical location, host species, morphological diversity, and genomic diversity. Additionally, recent studies have highlighted the potential of these phages based on host range, in vitro evaluation of performance and stability, and interaction with biofilms. This comprehensive analysis enables a better understanding of the steps involved in using these phages for therapeutic purposes.

Isolation of lytic bacteriophages and their relationships with the adherence genes of Staphylococcus saprophyticus

OBJECTIVE

This study aimed to introduce a lytic bacteriophage against Staphylococcus saprophyticus from wastewater in Gorgan, northern Iran.

RESULTS

The vB_SsapS-46 phage was isolated from urban wastewater and formed round and clear plaques on bacterial culture. It was visualized by electron microscopy and had a large head (approximately 106 nm) and a long tail (approximately 150 nm), indicating that it belongs to the Siphoviridae family. The host range of vB_SsapS-46 was determined using a spot test on 35 S. saprophyticus clinical isolates, and it was able to lyse 12 of the 35 clinical isolates (34%). Finally, the relationship between phage sensitivity and adherence genes was assessed, revealing no significant correlation between phage sensitivity and the frequency of adherence genes. The vB_SsapS-46 phage can be used alone or in a mixture in future studies to control urinary tract infections caused by this bacterium, especially in the elimination of drug-resistant pathogens.

A simplified method of bacteriophage preparation for transmission electron microscope

Bacteriophages are viruses that infect bacteria. Researchers use different methods to study the characteristics of bacteriophages. Transmission electron microscope (TEM) is considered the best method to analyze these characteristics. However, the quality of TEM micrographs is significantly influenced by the preparation methods used to prepare the bacteriophages sample. In this study, researchers compared two different methods for preparing the bacteriophage samples. In one method was used SM buffer, while in the other used deionized water. The results were analyzed by TEM and compared with each other. Additionally, the viability of bacteriophage in deionized water and SM buffer at 4°C was determined through plaque assay within 72 hours. TEM micrographs showed that the quality of bacteriophage sample prepared with deionized water is superior to those prepared with SM buffer. Furthermore, the titer of the bacteriophages did not show a significant reduction during 72 hours in both SM and deionized water. In conclusion, the results suggested that preparation method can significantly impact the quality of TEM micrographs. Using sterile deionized water for the preparation of bacteriophages is a simple way to improve the quality of TEM micrographs and it is advisable to send the samples to the laboratory within 72 hours.

Genomic analysis of vB_PaS-HSN4 bacteriophage and its antibacterial activity (in vivo and in vitro) against Pseudomonas aeruginosa isolated from burn

The most frequent infections caused by Pseudomonas aeruginosa are local infections in soft tissues, including burns. Today, phage use is considered a suitable alternative to cure infections caused by multi-drug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. We investigated the potential of a novel phage (vB_PaS-HSN4) belonging to Caudoviricetes class, against XDR and MDR P. aeruginosa strains in vivo and in vitro. Its biological and genetic characteristics were investigated. The phage burst size and latent were 119 and 20 min, respectively. It could tolerate a broad range of salt concentrations, pH values, and temperatures. The combination with ciprofloxacin significantly enhanced biofilm removal after 24 h. The genome was dsDNA with a size of 44,534 bp and encoded 61 ORFs with 3 tRNA and 5 promoters. No virulence factor was observed in the phage genome. In the in vivo infection model, treatment with vB_PaS-HSN4 increased Galleria mellonella larvae survival (80%, 66%, and 60%) (MOI 100) and (60%, 40%, and 26%) (MOI 1) in the pre-treatment, co-treatment, and post-treatment experiments, respectively. Based on these characteristics, it can be considered for the cure of infections of burns caused by P. aeruginosa.

Phage JS02, a putative temperate phage, a novel biofilm-degrading agent for Staphylococcus aureus

Staphylococcus aureus is a biofilm-producing organism that is frequently isolated from various environments worldwide. Because of the natural resistance of S. aureus biofilm to antibiotics, bacteriophages are considered as a promising alternative for its removal. The bacteriophage vB_SauS_JS02 was isolated from livestock wastewater and showed activity against multidrug-resistant (MDR) S. aureus. The phage vB_SauS_JS02 exhibited broad host range and possessed a large burst size (52 PFU/CFU) as well as moderate pH stability (4-11) and appropriate thermal tolerance (40-50 ºC). Electron microscopy and genome sequence revealed that vB_SauS_JS02 belonged to Triavirus genus in Siphoviridae family. Genetic analysis of the 46 kb sequence of vB_SauS_JS02 revealed 66 ORFs. The predicted protein products of the ORFs were clustered functionally into five groups as follows: replication/regulation, DNA packaging, structure/morphogenesis, lysis, and lysogeny. Although the phage vB_SauS_JS02 was a temperate phage, it exhibited a higher inhibiting and degrading activity against planktonic cells (80~90% reduction), even to S. aureus biofilm (∼68% reduction in biofilm formation). Moreover, the removal activity of the phage vB_SauS_JS02 against both planktonic cells and S. aureus biofilms was even better than that of the antibiotic (ceftazidime). In summary, the present study introduced the phage vB_SauS_JS02 as a potential biocontrol agent against biofilm-producing S. aureus after making it virulent. It may be applicable for phage therapy.

Bacteriophage therapy for inhibition of multi drug-resistant uropathogenic bacteria: a narrative review

Multi-Drug Resistant (MDR) uropathogenic bacteria have increased in number in recent years and the development of new treatment options for the corresponding infections has become a major challenge in the field of medicine. In this respect, recent studies have proposed bacteriophage (phage) therapy as a potential alternative against MDR Urinary Tract Infections (UTI) because the resistance mechanism of phages differs from that of antibiotics and few side effects have been reported for them. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis are the most common uropathogenic bacteria against which phage therapy has been used. Phages, in addition to lysing bacterial pathogens, can prevent the formation of biofilms. Besides, by inducing or producing polysaccharide depolymerase, phages can easily penetrate into deeper layers of the biofilm and degrade it. Notably, phage therapy has shown good results in inhibiting multiple-species biofilm and this may be an efficient weapon against catheter-associated UTI. However, the narrow range of hosts limits the use of phage therapy. Therefore, the use of phage cocktail and combination therapy can form a highly attractive strategy. However, despite the positive use of these treatments, various studies have reported phage-resistant strains, indicating that phage–host interactions are more complicated and need further research. Furthermore, these investigations are limited and further clinical trials are required to make this treatment widely available for human use. This review highlights phage therapy in the context of treating UTIs and the specific considerations for this application.

Biological characteristics and genome analysis of a novel phage vB_KpnP_IME279 infecting Klebsiella pneumoniae

Klebsiella pneumoniae (family Enterobacteriaceae) is a gram-negative bacterium that has strong pathogenicity to humans and can cause sepsis, pneumonia, and urinary tract infection. In recent years, the unreasonable use of antibacterial drugs has led to an increase in drug-resistant strains of K. pneumoniae, a serious threat to public health. Bacteriophages, viruses that infect bacteria, are ubiquitous in the natural environment. They are considered to be the most promising substitute for antibiotics because of their high specificity, high efficiency, high safety, low cost, and short development cycle. In this study, a novel phage designated vB_KpnP_IME279 was successfully isolated from hospital sewage using a multidrug-resistant strain of K. pneumoniae as an indicator. A one-step growth curve showed that vB_KpnP_IME279 has a burst size of 140 plaque-forming units/cell and a latent period of 20 min at its optimal multiplicity of infection (MOI = 0.1). Phage vB_KpnP_IME279 survives in a wide pH range between 3 and 11 and is stable at temperatures ranging from 40 to 60 °C. Ten of the 20 strains of K. pneumoniae including the host bacteria were lysed by the phage vB_KpnP_IME279, and the multilocus sequence typing and wzi typing of the 10 strains were ST11, ST37, ST375, wzi209, wzi52, and wzi72, respectively. The genome of vB_KpnP_IME279 is 42,518 bp long with a G + C content of 59.3%. Electron microscopic observation showed that the phage belongs to the family Podoviridae. BLASTN alignment showed that the genome of the phage has low similarity with currently known phages. The evolutionary relationship between phage vB_KpnP_IME279 and other Podoviridae was analyzed using a phylogenetic tree based on sequences of phage major capsid protein and indicates that the phage vB_KpnP_IME279 belongs to the Podoviridae subfamily. These data enhance understanding of K. pneumoniae phages and will help in development of treatments for multidrug-resistant bacteria using phages.

Isolation, Characterization and Genomic Analysis of a Novel Bacteriophage VB_EcoS-Golestan Infecting Multidrug-Resistant Escherichia coli Isolated from Urinary Tract Infection

Escherichia coli (E. coli) is one of the most common uropathogenic bacteria. The emergence of multi-drug resistance among these bacteria resulted in a worldwide public health problem which requires alternative treatment approaches such as phage therapy. In this study, phage VB_EcoS-Golestan, a member of Siphoviridae family, with high lytic ability against E. coli isolates, was isolated from wastewater. Its burst size was large and about 100 plaque-forming units/infected cell, rapid adsorption time, and high resistance to a broad range of pH and temperatures. Bioinformatics analysis of the genomic sequence suggests that VB_EcoS-Golestan is a new phage closely related to Escherichia phages in the Kagunavirus genus, Guernseyvirinae subfamily of Siphoviridae. The genome size was 44829 bp bp that encodes 78 putative ORFs, no tRNAs, 7 potential promoter sequences and 13 Rho-factor-independent terminators. No lysogenic mediated genes were detected in VB_EcoS-Golestan genome. Overall VB_EcoS-Golestan might be used as a potential treatment approach for controlling E. coli mediated urinary tract infection, however, further studies are essential to ensure its safety.

Environmental safety and biosafety in construction biotechnology

The topics of Construction Biotechnology are the development of construction biomaterials and construction biotechnologies for soil biocementation, biogrouting, biodesaturation, bioaggregation and biocoating. There are known different biochemical types of these biotechnologies. The most popular construction biotechnology is based on precipitation of calcium carbonate initiated by enzymatic hydrolysis of urea which follows with release of ammonia and ammonium to environment. This review focuses on the hazards and remedies for construction biotechnologies and on the novel environmentally friendly biotechnologies based on precipitation of hydroxyapatite, decay of calcium bicarbonate, and aerobic oxidation of calcium salts of organic acids. The use of enzymes or not living bacteria are the best options to ensure biosafety of construction biotechnologies. Only environmentally safe construction biotechnologies should be used for such environmental and geotechnical engineering works as control of the seepage in dams, channels, landfills or tunnels, sealing of the channels and the ponds, prevention of soil erosion and soil dust emission, mitigation of soil liquefaction, and immobilization of soil pollutants.