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Background Antibiotic resistance among pathogenic bacteria has created a global emergency, prompting the hunt for an alternative cure. Bacteriophages were discovered over a century ago and have proven to be a successful replacement during antibiotic treatment failure. This review discusses on the scientific investigation of phage therapy for Gram-positive pathogens and general outlook of phage therapy clinical trials and commercialization. Main body of the abstract This review aimed to highlight the phage therapy in Gram-positive bacteria and the need for phage therapy in the future. Phage therapy to treat Gram-positive bacterial infections is in use for a very long time. However, limited review on the phage efficacy in Gram-positive bacteria exists. The natural efficiency and potency of bacteriophages against bacterial strains have been advantageous amidst the other non-antibiotic agents. The use of phages to treat oral biofilm, skin infection, and recurrent infections caused by Gram-positive bacteria has emerged as a predominant research area in recent years. In addition, the upsurge in research in the area of phage therapy for spore-forming Gram-positive bacteria has added a wealth of information to phage therapy. Short conclusion We conclude that the need of phage as an alternative treatment is obvious in future. However, phage therapy can be used as reserve treatment. This review focuses on the potential use of phage therapy in treating Gram-positive bacterial infections, as well as their therapeutic aspects. Furthermore, we discussed the difficulties in commercializing phage drugs and their problems as a breakthrough medicine.

Plant growth promoting rhizobacteria arewidely exploited for the management of various fungal and bacterial diseases in plants. However, antiviral action of PGPR and their efficiency have been rarely investigated. In the present study, influential diversity of Bacillus species was related with tobacco streak virus (TSV) infection in cotton. The study revealed that, the population of B. subtilis, B. licheniformis and B. velezensis in rhizosphere of apparently healthy cotton plants were comparatively higher than TSV infected plants, indicating that they efficiently colonized the rhizosphere. Similarly, the population of the endophytic B. cereus and B. licheniformis were relatively higher in apparently healthy than TSV infected cotton plants. In vitro screening of rhizospheric, endophytic Bacillus species and phyto-antiviral principles revealed that rhizospheric B. amyloliquefaciens (VB7) and endophytic B. licheniformis (CoEH6) were effective in the suppression of TSV symptoms in indicator host (cowpea). The strain B. amyloliquefaciens (VB7) contained ten antimicrobial peptide genes responsible for the biosynthesis of antibiotics including, iturin, bacilysin, bacillomycin, surfactin, subtilin, and subtilosin. Moreover, the strain VB7 is reported to secrete pentadecenoic acid, heptadecenoic acid, octadecenoicacid, pyrrolo, piperazinedione and tetradecenoic acid, which would have together complemented in the antiviral activity. Upon simultaneous inoculation of the bacterium or phyto-antiviral principles with TSV in the indicator host plant, revealed that B. amyloliquefaciens (VB7) and M. jalapa were much effective and reduced the number of lesions up to 2.22/leaf and 3.00/leaf respectively compared with TSV inoculated control (25.28 lesions cm−2 area). Further, under field conditions, soil application and foliar spray of the B. amyloliquefaciens (VB7) resulted in 52 per cent reduction in TSV incidence. For reference TSV incidence in B. amyloliquefaciens (VB7) treated and untreated plots were 21.67 (PDI) and 45 (PDI) respectively. Moreover, B. amyloliquefaciens (VB7) improved seed cotton yield upto 149.45 g/plant compared to control (97.71 g/plant). Thus B. amyloliquefaciens (VB7) was exploited as an efficient antagonist for the management of TSV in cotton.

The emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE) in urinary tract infection among diabetic patients have become an increasing concern for management and treatment of the patients. The aim of this study was to investigate the genotypic features of CRE strains isolated from urinary tract infection among type 2 diabetes mellitus patients. A total of 1560 diabetic patients were screened for suspected urinary tract infection. 277 Gram negative bacteria were identified by Phoenix 100 system (Becton-Dickinson, USA). These isolates were screened for their ability to produce carbapenemases by a disc diffusion test. A total of 45 CRE isolates were recovered from these Gram negative bacteria. Carbapenamase producing isolates were screened for blaSPM, blaNDM, blaIMP, blaVIM, and blaGIM genes. The PCR products were sequenced in an ABI 3500 DNA sequencer (Applied Biosystems, USA). blaIMP-1, blaIMP-8, blaNDM-1, blaNDM-2, and blaNDM-4 were the predominant genes seen among E.coli, Klebsiella pneumoniae, Citrobacter freundii, Acinetobacter baumannii and Proteus mirabilis. Colistin and Amikacin were the drug of choice and Colistin had the MIC value of < 1mg/l and for Amikacin 62% of isolates had MIC value of < 4mg/l. This rising trend of carbapenem resistance among Gram negative bacteria stresses the increasing importance of continuous surveillance system and stewardship of antibiotics as strategies in the overall management of diabetic patients with urinary tract infection.

Role of plant growth promoting rhizobacteria (PGPR) in growth promotion and induction of resistance against various plant pathogens have been extensively studied. However, MAMP (Microbe Associated Molecular Pattern) triggered immunity (MTI) against plant viruses are not well exploited. The present study enlightens the role of two MAMP genes including, flagellin (Flg) and elongation factor (EF-Tu) in the induction of plant defense against GBNV infecting tomato. Secondary metabolites of Bacillus amyloliquefaciens (VB7), effectively suppressed GBNV symptom expression up to 84% compared to untreated control in cowpea, the indicator host plant. Agrobacterium tumefaciens EHA105 clones expressing the MAMP genes were drenched in the root zone to assess the induction of resistance against GBNV in tomato. Treatment with A. tumefaciens EHA105 clones containing flagellin (Ag- Ba.Flg) and elongation factor-TU (Ag-Ba.EF-Tu) genes as soil drench and foliar spray, reduced virus titre,0.369 OD and 0.379 OD respectively as compared to control 1.249 OD. The disease severity was reduced up to 15% in Ag-Ba.Flg treated plants compared to 88.25% in inoculated control. Further there was an increased expression of defense associated genes including, MAPKK1, WRKY33BB, NPR1 and PR1.The present investigation clearly indicated the efficiency of MAMP genes in triggering defense mechanism in tomato against GBNV.

The beneficial microbes are used to manage the plant diseases for sustainable agriculture production, which are alternatives to chemical fertilizers and pesticides. A key parameter in the effective management of plant disease is to protect the crop before the establishment of pathogen in an infection court. Recently, Bacillus species have been well demonstrated for its effectiveness against plant diseases, since it is most common bacteria found to colonize plants easily. Bacillus sp. inhibits the growth of phytopathogens directly or indirectly, through competition of space and nutrients. In addition, a wide variety of secondary metabolites are produced by Bacillus species that shows their ability as biocontrol agents against various plant diseases. Many potent Bacillus spp. possess secondary metabolites, including the difficidin, polyketides, and bacillaene. The Bacillus isolates produce several antimicrobial lipopeptides genes including fengycin, iturin, bacillomycin D, and surfactin. The resultant products of these molecules have been reported to inhibit fungal and bacterial diseases in crops. The indirect mode of action includes promoting plant growth and stimulation of the defense mechanism that trigger the first line of defense. These microbes have been known to facilitate a diverse mechanisms like quorum sensing (QS) for plant signal interference, production of volatile organic compounds (VOCs), displaying antimicrobial activity and induction of systemic resistance, thereby promoting beneficial plant–microbe interactions. Besides, the endospore-forming ability of the bacteria enhances their survival capability under diverse environmental conditions. Lastly, the antibiotic production induced resistance and growth promotion action mediated by Bacillus spp. as an effective management tool for plant disease control, since it is durable and environment-friendly alternative for chemical-based plant disease management.

Bacillus species are widely exploited as biocontrol agents because of their efficiency in impeding various plant pathogens with multifaceted approach. In this study, Bacillus species were isolated from rhizosphere of various plants viz., carnations, cotton, turmeric, and bananas in Tamil Nadu state of India. Their potential to control the mycelial growth of Sclerotinia sclerotiorum was assessed in vitro by dual plate and partition plate techniques. B. amyloliquefaciens strain VB7 was much effective in inhibiting mycelial growth (45% inhibition of over control) and sclerotial production (100%). PCR detection of AMP genes revealed that B. amyloliquefaciens (VB7) had a maximum of 10 diverse antibiotic biosynthesis genes, namely, ituD, ipa14, bacA, bacD, bamC, sfP, spaC, spaS, alba, and albF, that resulted in production of the antibiotics iturin, bacilysin, bacillomycin, surfactin, subtilin, and subtilosin. Further, metabolites from B. amyloliquefaciens strains VB2 and VB7, associated with inhibition of S. sclerotiorum, were identified as phenols and fatty acids by gas chromatography mass spectrometry (GC-MS). Delivery of bacterial suspension of the effective strains of Bacillus spp. as root dip was found promising for the management of stem rot of cultivated carnations. Minimal percent disease incidence (4.6%) and maximum plant growth promotion was observed in the plants treated with B. amyloliquefaciens (VB7).

Drug resistance is the major cause of increase in morbidity and mortality in neonates. One thousand six hundred forty-seven suspected septicemic neonates were subjected for microbiological analysis over a period of 5 years. Forty-two P. aeruginosa were isolated and the antibiogram revealed that 28 P. aeruginosa were resistant to almost all the common drugs used (multidrug-resistant). The emergence of antibiotic-resistant bacterial strains is one of the most critical problems of modern medicine. As a result, a novel and most effective approaches for treating infection caused by multidrug-resistant bacteria are urgently required. In this context, one intriguing approach is to use bacteriophages (viruses that kill bacteria) in the treatment of infection caused by drug-resistant bacteria. In the present study, the utility of lytic bacteriophages to rescue septicemic mice with multidrug-resistant (MDR) P. aeruginosa infection was evaluated. MDR P. aeruginosa was used to induce septicemia in mice by intraperitoneal (i.p.) injection of 10 7 CFU. The resulting bacteremia was fatal within 48 hrs. The phage strain used in this study had lytic activity against a wide range of clinical isolates of MDR P. aeruginosa. A single i.p. injection of 3 × 10 9 PFU of the phage strain, administered 45 min after the bacterial challenge, was sufficient to rescue 100% of the animals. Even when treatment was delayed to the point where all animals were moribund, approximately 50% of them were rescued by a single injection of this phage preparation. The ability of this phage to rescue septicemic mice was demonstrated to be due to the functional capabilities of the phage and not to a nonspecific immune effect. The rescue of septicemic mice could be affected only by phage strains able to grow in vitro on the bacterial host used to infect the animals and when such strains are heat-inactivated, they lose their ability to rescue the infected mice. Multidrug-resistant bacteria have opened a second window for phage therapy. It would seem timely to begin to look afresh at this approach. A scientific methodology can make phage therapy as a stand-alone therapy for infections that are fully resistant to antibiotics.