Staphyphage: Biorisk Reduction in MRSA Research

Staphylococcus aureus is an opportunistic human pathogen that has the ability to cause both health care-associated and community-acquired infections [1]. It has been identified as one of the ‘high priority pathogen’ by the World Health Organization (WHO) [5] The infections were once, easily treated with antibiotics before resistance against beta-lactams (eg. Methicillin) and glycopeptides (eg. Vancomycin) began to emerge over the years and caused an increase in mortality and morbidity rates in patients infected with S. aureus [2,3]. This has led to an increased interest in the exploration of the use of bacteriophage as an alternative approach way to combat MRSA because a bacteriophage has bacteriolytic mechanism independent from those of any known antibiotics [5]. The availability of a virulent and broad spectrum bacteriophage against MRSA may significantly reduce the overall biorisk as it acts as an effective treatment in case of exposure

Could bacteriophages isolated from the sewage be the solution to methicillin-resistant Staphylococcus aureus?

Introductions: The emergence of multidrug-resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA) complicates the treatment of the simplest infection. Although glycopeptides such as vancomycin still proves to be effective in treating MRSA infections, the emergence of vancomycin-resistant strains limits the long term use of this antibiotic. Bacteriophages are ubiquitous bacterial viruses which is capable of infecting and killing bacteria including its antibiotic-resistant strains. Bactericidal bacteriophages use mechanisms that is distinct from antibiotics and is not affected by the antibioticresistant phenotypes. Objectives: The study was undertaken to evaluate the possibility to isolate bacteriolytic bacteriophages against S.aureus from raw sewage water and examine their efficacy as antimicrobial agents in vitro. Methods: Bacteriophages were isolated from the raw sewage using the agar overlay method. Isolated bacteriophages were plaque purified to obtain homogenous bacteriophage isolates. The host range of the bacteriophages was determined using the spot test assay against the 25 MRSA and 36 MSSA isolates obtained from the Sarawak General Hospital. Staphylococcus saprophyticus, Staphylococcus sciuri and Staphylococcus xylosus were included as non-SA controls. The identity of the bacteriophages was identified via Transmission Electron Microscopy and genomic size analysis. Their stability at different pH and temperature were elucidated. Results: A total of 10 lytic bacteriophages infecting S.aureus were isolated and two of them namely ΦNUSA-1 and ΦNUSA-10 from the family of Myoviridae and Siphoviridae respectively exhibited exceptionally broad host range against >80% of MRSA and MSSA tested. Both bacteriophages were specific to S.aureus and stable at both physiologic pH and temperature. Conclusion: This study demonstrated the abundance of S.aureus specific bacteriophages in raw sewage. Their high virulence against both MSSA and MRSA is an excellent antimicrobial characteristic which can be exploited for bacteriophage therapy against MRSA

Evaluation of the efficacy of bacteriophages against Staphylococcus aureus

Staphylococcus aureus (S. aureus) is an opportunistic human pathogen that has the ability to cause both health care-associated and community-acquired infections (Chambers, 2001). The infections were once, easily treated with antibiotics before resistance against beta-lactams (eg. Methicillin) and glycopeptides (eg. Vancomycin) began to emerge over the years and caused an increase in mortality and morbidity rates in patients infected with S. aureus (Boucher & Corey, 2008, Howe et al., 1998). This has led to an increased interest in the exploration of the use of bacteriophages as a way to combat multi-drug resistant organisms because bacteriophages has bacteriolytic mechanism independent from those of any known antibiotics (Matsuzaki et al., 2005)

Could bacteriophages isolated from the sewage be the solution to methicillin-resistant Staphylococcus aureus?

Introductions: The emergence of multidrug-resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA) complicates the treatment of the simplest infection. Although glycopeptides such as vancomycin still proves to be effective in treating MRSA infections, the emergence of vancomycin-resistant strains limits the long term use of this antibiotic. Bacteriophages are ubiquitous bacterial viruses which is capable of infecting and killing bacteria including its antibiotic-resistant strains. Bactericidal bacteriophages use mechanisms that is distinct from antibiotics and is not affected by the antibioticresistant phenotypes. Objectives: The study was undertaken to evaluate the possibility to isolate bacteriolytic bacteriophages against S.aureus from raw sewage water and examine their efficacy as antimicrobial agents in vitro. Methodology: Bacteriophages were isolated from the raw sewage using the agar overlay method. Isolated bacteriophages were plaque purified to obtain homogenous bacteriophage isolates. The host range of the bacteriophages was determined using the spot test assay against the 25 MRSA and 36 MSSA isolates obtained from the Sarawak General Hospital. Staphylococcus saprophyticus, Staphylococcus sciuri and Staphylococcus xylosus were included as non-SA controls. The identity of the bacteriophages was identified via Transmission Electron Microscopy and genomic size analysis. Their stability at different pH and temperature were elucidated. Results: A total of 10 lytic bacteriophages infecting S.aureus were isolated and two of them namely ΦNUSA-1 and ΦNUSA-10 from the family of Myoviridae and Siphoviridae respectively exhibited exceptionally broad host range against >80% of MRSA and MSSA tested. Both bacteriophages were specific to S.aureus and stable at both physiologic pH and temperature. Conclusion: This study demonstrated the abundance of S.aureus specific bacteriophages in raw sewage. Their high virulence against both MSSA and MRSA is an excellent antimicrobial characteristic which can be exploited for bacteriophage therapy against MRSA

Pediatric melioidosis in Sarawak, Malaysia: Epidemiological, clinical and microbiological characteristics

Background Melioidosis is a serious, and potentially fatal community-acquired infection endemic to northern Australia and Southeast Asia, including Sarawak, Malaysia. The disease, caused by the usually intrinsically aminoglycoside-resistant Burkholderia pseudomallei, most commonly affects adults with predisposing risk factors. There are limited data on pediatric melioidosis in Sarawak. Methods A part prospective, part retrospective study of children aged <15 years with culture-confirmed melioidosis was conducted in the 3 major public hospitals in Central Sarawak between 2009 and 2014. We examined epidemiological, clinical and microbiological characteristics. Findings Forty-two patients were recruited during the 6-year study period. The overall annual incidence was estimated to be 4.1 per 100,000 children <15 years, with marked variation between districts. No children had pre-existing medical conditions. Twenty-three (55%) had disseminated disease, 10 (43%) of whom died. The commonest site of infection was the lungs, which occurred in 21 (50%) children. Other important sites of infection included lymph nodes, spleen, joints and lacrimal glands. Seven (17%) children had bacteremia with no overt focus of infection. Delays in diagnosis and in melioidosis-appropriate antibiotic treatment were observed in nearly 90% of children. Of the clinical isolates tested, 35/36 (97%) were susceptible to gentamicin. Of these, all 11 isolates that were genotyped were of a single multi-locus sequence type, ST881, and possessed the putative B. pseudomallei virulence determinants bimABp, fhaB3, and the YLF gene cluster. Conclusions Central Sarawak has a very high incidence of pediatric melioidosis, caused predominantly by gentamicin-susceptible B. pseudomallei strains. Children frequently presented with disseminated disease and had an alarmingly high death rate, despite the absence of any apparent predisposing risk factor

Pediatric melioidosis in Sarawak, Malaysia: Epidemiological, clinical and microbiological characteristics.

Melioidosis is a serious, and potentially fatal community-acquired infection endemic to northern Australia and Southeast Asia, including Sarawak, Malaysia. The disease, caused by the usually intrinsically aminoglycoside-resistant Burkholderia pseudomallei, most commonly affects adults with predisposing risk factors. There are limited data on pediatric melioidosis in Sarawak.A part prospective, part retrospective study of children aged <15 years with culture-confirmed melioidosis was conducted in the 3 major public hospitals in Central Sarawak between 2009 and 2014. We examined epidemiological, clinical and microbiological characteristics.Forty-two patients were recruited during the 6-year study period. The overall annual incidence was estimated to be 4.1 per 100,000 children <15 years, with marked variation between districts. No children had pre-existing medical conditions. Twenty-three (55%) had disseminated disease, 10 (43%) of whom died. The commonest site of infection was the lungs, which occurred in 21 (50%) children. Other important sites of infection included lymph nodes, spleen, joints and lacrimal glands. Seven (17%) children had bacteremia with no overt focus of infection. Delays in diagnosis and in melioidosis-appropriate antibiotic treatment were observed in nearly 90% of children. Of the clinical isolates tested, 35/36 (97%) were susceptible to gentamicin. Of these, all 11 isolates that were genotyped were of a single multi-locus sequence type, ST881, and possessed the putative B. pseudomallei virulence determinants bimABp, fhaB3, and the YLF gene cluster.Central Sarawak has a very high incidence of pediatric melioidosis, caused predominantly by gentamicin-susceptible B. pseudomallei strains. Children frequently presented with disseminated disease and had an alarmingly high death rate, despite the absence of any apparent predisposing risk factor

Clinical and microbiological features of 11 patients whose <i>B</i>. <i>pseudomallei</i> isolates were available for molecular characterization.

<p>Clinical and microbiological features of 11 patients whose <i>B</i>. <i>pseudomallei</i> isolates were available for molecular characterization.</p

Average annual incidence of pediatric melioidosis by district within the Central region of Sarawak.

<p>The map of Borneo shows the Malaysian states of Sarawak and Sabah, and the location of the 3 study sites. The map insert depicts the average annual incidences of pediatric melioidosis in each district in Central Sarawak. The incidence per 100,000 children <15 years/ year, in each district, is labelled.</p

Demographic, presenting clinical features on admission, subsequent findings and outcome of 42 children with culture-confirmed melioidosis.

<p>Demographic, presenting clinical features on admission, subsequent findings and outcome of 42 children with culture-confirmed melioidosis.</p

Primary and secondary infection sites in 42 cases of culture-confirmed pediatric melioidosis.

<p>Primary and secondary infection sites in 42 cases of culture-confirmed pediatric melioidosis.</p