The Citizen Phage Library: Rapid Isolation of Phages for the Treatment of Antibiotic Resistant Infections in the UK.

Antimicrobial resistance poses one of the greatest threats to global health and there is an urgent need for new therapeutic options. Phages are viruses that infect and kill bacteria and phage therapy could provide a valuable tool for the treatment of multidrug-resistant infections. In this study, water samples collected by citizen scientists as part of the Citizen Phage Library (CPL) project, and wastewater samples from the Environment Agency yielded phages with activity against clinical strains Klebsiella pneumoniae BPRG1484 and Enterobacter cloacae BPRG1482. A total of 169 and 163 phages were found for K. pneumoniae and E. cloacae, respectively, within four days of receiving the strains. A third strain (Escherichia coli BPRG1486) demonstrated cross-reactivity with 42 E. coli phages already held in the CPL collection. Seed lots were prepared for four K. pneumoniae phages and a cocktail combining these phages was found to reduce melanisation in a Galleria mellonella infection model. The resources and protocols utilised by the Citizen Phage Library enabled the rapid isolation and characterisation of phages targeted against multiple strains. In the future, within a clearly defined regulatory framework, phage therapy could be made available on a named-patient basis within the UK.

Phage Therapy of Mycobacterium Infections: Compassionate Use of Phages in 20 Patients With Drug-Resistant Mycobacterial Disease.

BACKGROUND: Nontuberculous Mycobacterium infections, particularly Mycobacterium abscessus, are increasingly common among patients with cystic fibrosis and chronic bronchiectatic lung diseases. Treatment is challenging due to intrinsic antibiotic resistance. Bacteriophage therapy represents a potentially novel approach. Relatively few active lytic phages are available and there is great variation in phage susceptibilities among M. abscessus isolates, requiring personalized phage identification. METHODS: Mycobacterium isolates from 200 culture-positive patients with symptomatic disease were screened for phage susceptibilities. One or more lytic phages were identified for 55 isolates. Phages were administered intravenously, by aerosolization, or both to 20 patients on a compassionate use basis and patients were monitored for adverse reactions, clinical and microbiologic responses, the emergence of phage resistance, and phage neutralization in serum, sputum, or bronchoalveolar lavage fluid. RESULTS: No adverse reactions attributed to therapy were seen in any patient regardless of the pathogen, phages administered, or the route of delivery. Favorable clinical or microbiological responses were observed in 11 patients. Neutralizing antibodies were identified in serum after initiation of phage delivery intravenously in 8 patients, potentially contributing to lack of treatment response in 4 cases, but were not consistently associated with unfavorable responses in others. Eleven patients were treated with only a single phage, and no phage resistance was observed in any of these. CONCLUSIONS: Phage treatment of Mycobacterium infections is challenging due to the limited repertoire of therapeutically useful phages, but favorable clinical outcomes in patients lacking any other treatment options support continued development of adjunctive phage therapy for some mycobacterial infections.

Engineered bacteriophages for treatment of a patient with a disseminated drug-resistant Mycobacterium abscessus.

A 15-year-old patient with cystic fibrosis with a disseminated Mycobacterium abscessus infection was treated with a three-phage cocktail following bilateral lung transplantation. Effective lytic phage derivatives that efficiently kill the infectious M. abscessus strain were developed by genome engineering and forward genetics. Intravenous phage treatment was well tolerated and associated with objective clinical improvement, including sternal wound closure, improved liver function, and substantial resolution of infected skin nodules.

Reduction of blood stream infections in children following a change to chlorhexidine disinfection of parenteral nutrition catheter connectors.

BACKGROUND & AIMS: Catheter-related-blood-stream-infection (CRBSI) might be prevented by optimal catheter connector antisepsis in children with intestinal failure on parenteral nutrition (PN). We changed the disinfectant used from isopropanol 70% to chlorhexidine 2% in 70% isopropanol, which leaves a residue of chlorhexidine on the connector. METHODS: We conducted this before/after study in children treated with PN for >28 days. Episodes of CRBSI were recorded for all 42 children treated for >28 days during May-November 2006 before introducing chlorhexidine and for all 50 children treated in May-November 2007 after chlorhexidine was introduced. The number of hospital-acquired CRBSI and number of PN days was counted for each period. The rate of CRBSI/1000 catheter days and the proportion of patients that experienced at least one CRBSI during the two periods were compared. RESULTS: There were 3.1 CRBSI/1000 catheter days prior to using chlorhexidine and 0.4 CRBSI/1000 catheter days after it was introduced, p = 0.03. Prior to chlorhexidine 10/42 (24%) patients experienced at least one episode of CRBSI, compared to 3/50, (6%) after introducing it (p = 0.02). The survival rate in both periods was similar, but after chlorhexidine significantly more children made a full recovery and a lower proportion of children had irreversible intestinal failure (p = 0.01). CONCLUSIONS: Our results support the use of 2% chlorhexidine not only to reduce risk of sepsis for central venous catheter connector antisepsis in catheters used for intravenous nutrition, but also to improve the patients' chances of recovering intestinal function.

Use of bacteriophages in the treatment of Pseudomonas aeruginosa infections.

Phage therapy for Pseudomonas aeruginosa infections has been used for more than 50 years. Controlled investigation into its use dates from the early 1990s when positive laboratory studies of local and systemic infection were followed by clinical studies: symptomatic improvement and phage multiplication were seen in a pet dog with otitis and a human with an infected burn. Antibiotic resistance has renewed interest in this approach. There have been recent positive reports in the treatment of experimental animal infection including systemic and respiratory infections. Phages have shown promise against experimental biofilms. Two small recent clinical trials in otitis, of dogs and of human patients have provided some encouraging results. Phage has potential in the treatment of antibiotic resistant infection by P. aeruginosa. Hence, full scale clinical trials are needed.

Central venous catheter-associated bloodstream infections in a pediatric intensive care unit: effect of the location of catheter insertion.

OBJECTIVE: To compare the rate of central venous catheter-associated bloodstream infections between pediatric intensive care unit admissions where central venous catheters were inserted within the same hospital (internal central venous catheters) and those where central venous catheters were inserted before transfer from other hospitals (external central venous catheters). DESIGN: Retrospective analysis of prospectively collected data. SETTING: A tertiary care pediatric intensive care unit in London, UK. PATIENTS: Consecutive pediatric intensive care unit admissions between May 2007 and March 2009. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Catheter-associated bloodstream infections were identified using a widely accepted surveillance definition. The rate and time to occurrence of catheter-associated bloodstream infection were compared between internal and external nontunneled central venous catheters. A multilevel Cox-regression model was used to study the association between location of central venous catheter insertion and time to catheter-associated bloodstream infection. In total, 382 central venous catheters were studied (245 internal; 137 external) accounting for a total of 1,737 central venous catheter days. There was a higher catheter-associated bloodstream infection incidence density among external central venous catheters (23.1 [95% confidence interval 11.0-35.2] vs. 9.7 [95% confidence interval 3.9-15.5] per 1,000 catheter-days). Multivariable analyses demonstrated higher infection risk with external central venous catheters (hazard ratio 2.65 [95% confidence interval 1.18-5.96]) despite adjustment for confounding variables. CONCLUSIONS: The rate of catheter-associated bloodstream infections in the pediatric intensive care unit is significantly affected by external insertion of the central venous catheter. Future interventions to reduce nosocomial infections on pediatric intensive care units will need to be specifically targeted at this high-risk patient group.

Topical treatment of Pseudomonas aeruginosa otitis of dogs with a bacteriophage mixture: a before/after clinical trial.

In an evaluation of a bacteriophage treatment for infection, ten dogs were included with chronic Pseudomonas aeruginosa otitis. Each received, directly into the auditory canal of one ear, a single dose of a topical preparation containing approximately 1 × 10(5) plaque forming units (PFU) of each of 6 bacteriophage strains, active against P. aeruginosa. At the time of bacteriophage administration and 48 h later each dog's core temperature was taken, its ear was assigned a clinical score (higher=worse condition) and aural swabs were taken for bacteriophage and P. aeruginosa counts. Forty eight hours after treatment the clinical score and P. aeruginosa count of all ears had fallen (mean score fall: 30.1%, range 7.7-56.3%, p<0.0001; mean count fall: 67%, range 29.4-96.8%, p<0.001). The bacteriophage counts had risen from the administered dose (mean rise: 99.1-fold, range 2.8-433.3-fold). No treatment related inflammation or other adverse events were detected during the trial period. This is the first report of a veterinary clinical trial of a bacteriophage treatment of infection. The results show that administration of this topical bacteriophage mixture leads to lysis of P. aeruginosa in the ear without apparent toxicity and that it has potential to be a convenient and effective treatment for P. aeruginosa otitis in dogs.

A fall in bloodstream infections followed a change to 2% chlorhexidine in 70% isopropanol for catheter connection antisepsis: a pediatric single center before/after study on a hemopoietic stem cell transplant ward.

BACKGROUND: Some catheter-related bloodstream infections originate from catheter connectors; therefore, improved antisepsis of these might be expected to reduce the incidence of such infections. METHODS: In this observational before/after study at a pediatric tertiary referral hospital, inpatients up to 16 years old undergoing hemopoietic stem cell transplants were studied. Catheter connection antisepsis was changed from 70% isopropanol alone to 2% chlorhexidine in 70% isopropanol. Numbers of catheter-related bloodstream infections before and after the change were monitored as were the numbers of catheter days experienced by patients. RESULTS: The infection rate before the change was 12 per 1000 catheter-days, and, following the change, this fell to 3 per 1000 catheter-days (P=.004). Similar falls followed the introduction of chlorhexidine to other wards. CONCLUSION: The introduction of chlorhexidine was followed by a profound, sustained fall in catheter-related infections. The results support the 2007 United Kingdom guidelines recommending 2% chlorhexidine in 70% isopropanol as a disinfectant of needleless connectors and hubs of central venous catheters.

Bacterial counts from hospital doctors' ties are higher than those from shirts.

Doctor ties are often contaminated with bacteria, and it has been suggested that they should not be worn. We have compared bacterial counts from the ties and shirt pockets of 50 doctors. Counts were higher (P = .002) from ties that were rarely, if ever, cleaned than from shirts that were washed every 2 days or more frequently. The results support the need for further research on unwashable clothing of hospital staff.

Alginate lyase enhances antibiotic killing of mucoid Pseudomonas aeruginosa in biofilms.

Once mucoid (alginate-producing) strains of Pseudomonas aeruginosa have become established in the respiratory tracts of cystic fibrosis patients they can rarely be eliminated by antibiotic treatment alone; we have investigated, in an in vitro biofilm system, the putative role of co-administration of alginate lyase with antibiotic. Biofilms were maintained in continuous flow culture in a medium resembling sputum from CF patients. Antibiotics and/or alginate lyase were added to some of the cultures. Biofilms of two mucoid CF strains of P. aeruginosa were, in most cases, not eradicated by a one-week course of treatment with 64 microg/ml of gentamicin; the same concentration of gentamicin, under the same conditions, led to the apparent elimination of all biofilms of non-mucoid derivatives of these strains. When alginate lyase and gentamicin were administered together the apparent elimination of mucoid bacteria from biofilms was achieved, whereas the mucoid bacteria in most control biofilms treated only with gentamicin persisted. Ceftazidime treatment of biofilms was more effective against those containing the non-mucoid strains than those with mucoid strains. These studies support the view that co-administration of antibiotics with alginate lyase, which degrades the exopolysaccharide produced by mucoid strains of P aeruginosa, might benefit CF patients by increasing the efficacy of antibiotic in the respiratory tract.

Experimental bacteriophage protection against Staphylococcus aureus abscesses in a rabbit model.

In a rabbit model of wound infection caused by Staphylococcus aureus, 2 x 10(9) PFU of staphylococcal phage prevented abscess formation in rabbits when it was injected simultaneously with S. aureus (8 x 10(7) CFU) into the same subcutaneous site. Phage multiplied in the tissues. Phages might be a valuable prophylaxis against staphylococcal infection.