Phage therapy as a revolutionary medicine against Gram-positive bacterial infections.

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.

Episode of coexisting infections with multiple dengue virus serotypes in central Karnataka, India.

BACKGROUND: The co-circulation of multiple dengue virus serotypes has been reported in many parts of the world, including India; however, concurrent infection with more than one serotype of dengue virus in the same individual is rarely documented. METHOD: An outbreak of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) occurred in and around Davangere, Karnataka, from June 2011-March 2012. This is the first report from India with a high percentage of concurrent infections with different dengue virus serotypes circulating during one outbreak. Acute phase sera from patients were tested for the presence of dengue virus RNA by RT-PCR. RESULTS: Of the 72 samples tested for dengue virus RNA, 42 (58.3%) were positive. All four dengue virus serotypes were found to be co-circulating in this outbreak, and DENV-2 was the predominant serotype. In addition, concurrent infection with more than one dengue virus serotype was identified in 18 (42.9%) dengue virus-positive samples. CONCLUSION: Our study showed that serotype DEN-2 was dominant in the positive dengue virus-infected samples; the other serotype present was DEN-3. This is the first report of concurrent infections with different dengue virus serotypes in this part of the world.

Carbon particles in airway macrophage as a surrogate marker in the early detection of lung diseases.

BACKGROUND: It has been shown that inhalation of carbonaceous particulate matter may impair lung function in children. OBJECTIVE: Using the carbon content of airway macrophages as a marker of individual exposure to particulate matter derived from fossil fuel, we sought direct evidence for this association. METHODS: 300 children from puffed rice industrial areas and 300 children from population living in green zone were selected randomly. Airway macrophages were obtained from healthy children through sputum induction, and the grading of ultrafine carbon particles in airway macrophages was measured. Pulmonary function was also measured by spirometry. RESULTS: Pulmonary function tests showed that in industrial area 42.6% and 20.3% of children had moderate obstructive airway disease and restrictive airway disease, respectively. In the green zone area, 7% of children had obstructive airway disease and 6% had restrictive airway disease. Evaluation of airway macrophages for ultrafine carbon particles revealed that in industrial area there were ultrafine carbon particles of grade 2 in 23% of subjects and grade 3 in 8.33% of individuals with obstructive airway disease. In the green zone area, the rates were 1.67% and 0.7%, respectively. CONCLUSION: The study provides a first evidence of the strong association between air pollution and development of airway diseases. Carbon particles in the sputum can be used as a marker for air pollution.

Isolation of bacteriophages to multi-drug resistant Enterococci obtained from diabetic foot: a novel antimicrobial agent waiting in the shelf?

INTRODUCTION: While foot infections in persons with diabetes are initially treated empirically, therapy directed at known causative organisms may improve the outcome. Many studies have reported on the bacteriology of diabetic foot infections (DFIs), but the results have varied and have often been contradictory. The purpose of the research work is to call attention to a frightening twist in the antibiotic-resistant Enterococci problem in diabetic foot that has not received adequate attention from the medical fraternity and also the pharmaceutical pipeline for new antibiotics is drying up. MATERIALS AND METHODS: Adult diabetic patients admitted for lower extremity infections from July 2008 to December 2009 in the medical wards and intensive care unit of medical teaching hospitals were included in the study. The extent of the lower extremity infection on admission was assessed based on Wagner's classification from grades I to V. Specimens were collected from the lesions upon admission prior to the initiation of antibiotic therapy or within the first 48 h of admission. RESULTS: During the 18-month prospective study, 32 strains of Enterococcus spp. (26 Enterococcus faecalis and 06 E. faecium) were recovered. Antibiotic sensitivity testing was done by Kirby-Bauer's disk diffusion method. Isolates were screened for high-level aminoglycoside resistance (HLAR). A total of 65.6% of Enterococcus species showed HLAR. Multidrug resistance and concomitant resistance of HLAR strains to other antibiotics were quite high. None of the Enterococcus species was resistant to vancomycin. CONCLUSION: Multidrug-resistant Enterococci are a real problem and continuous surveillance is necessary. Today, resistance has rendered most of the original antibiotics obsolete for many infections, mandating the development of alternative anti-infection modalities. One of such alternatives stemming up from an old idea is the bacteriophage therapy. In the present study, we could able to demonstrate the viable phages against MDR E. faecalis.

Utility of lytic bacteriophage in the treatment of multidrug-resistant Pseudomonas aeruginosa septicemia in mice.

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 x 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.

Emergence of extended spectrum beta lactamase mediated resistance in neonatal septicemia.

This study was carried out in microbiology department of Gulbarga university, Gulbarga to find out the frequency of extended spectrum beta lactamase (ESbL) producing gram-negative bacilli isolated from neonatal septicemic cases. This study was carried out from Oct 2001 to June 2004. A total of 471 consecutive Gram-negative bacilli were recovered during the study period from blood samples. Extended spectrum beta lactamase detection in gram-negative isolates was carried out by double disk synergistic method on Mueller Hinton agar. A susceptibility disk containing amoxicillin-clavulanate was placed as the inhibitor of beta lactamase in the center of the plate, and cefotaxime, ceftazidime, ceftriaxone and aztreonam disks were placed 30 mm (center to center) from the amoxicillin-clavulanate disk. Enhancement of the zone of inhibition of the oxyimino-lactam caused by the synergy of the clavulanate in the amoxicillin-clavulanate disk was considered as evidence of ESbL production. Escherichia coli ATCC 25922 and K. pneumoniae ATCC 700603 were used as control strains. The frequency of ESbL producing gram-negative bacilli among the neonatal septicemic cases was 22.7%.

Bacteriophage in the treatment of experimental septicemic mice from a clinical isolate of multidrug resistant Klebsiella pneumoniae.

Drug resistance is the major cause of increase in morbidity and mortality in neonates. The emergence of antibiotic-resistant bacterial strains requires the exploration of alternative antibacterial therapies and the concern that human kind in re-entering the 'pre-antibiotic era' has become very real and the development of alternative anti-infection modalities has become one of the highest priorities of modern medicine and biotechnology. This has spurred biomedical researchers to expand their efforts to identify new technologies and products that employ novel mechanism of action against the "super-bugs". One of such alternatives stems up from an old idea is the bacteriophage therapy, which led our group to study the ability of bacterial viruses (bacteriophages or phages) to rescue septicemic mice with multidrug resistant (MDR) Klebsiella pneumoniae isolated from neonatal septicemia. The phage strain used in this study had lytic activity against a wide range of clinical isolates of MDR Klebsiella pneumoniae. One of these MDR Klebsiella strain was used to induce septicemia in mice by intraperitoneal (i.p.) injection of 10(9) CFU. The resulting bacteremia was fatal within 48 h. A single i.p. injection of 3x10(8) 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.

In vitro activity of norfloxacin against uropathogens and drug efficacy in simulated bladder model under diabetic conditions.

PURPOSE: The in vitro activity of norfloxacin was determined to maximize the correlation between susceptibility testing of the drug and the results of clinical therapy of urinary tract infection in diabetics. This study was carried out to observe the effect of changing concentration of norfloxacin on the growth of uropathogens under diabetic conditions. METHODS: The standard broth microdilution method was carried out to determine the minimum inhibitory concentration (MIC) using Mueller Hinton broth by varying pH of the medium (5.0, 5.5, 6.0, 6.5 and 7.0) and glucose concentration (100, 250, 500, 1000 and 2000 mg/dL). A specially designed mechanical bladder model system simulating hydrokinetic conditions that exist in the urinary tract of diabetics was employed. RESULTS: The loss of activity of norfloxacin was more pronounced (> four folds) at pH 5.0 and 2000 mg/dL sugar concentration. These findings were consistent with the experiment 'in vitro simulated bladder model' by exposing bacterial growth to varied norfloxacin and sugar concentration. CONCLUSIONS: Although norfloxacin is a drug of choice for non-diabetic and diabetic individuals with mild to moderate glucosuria, in severe diabetic individuals norfloxacin may not be an effective drug.