We wanted to present a case of neonatal mastitis and abscess caused by massage to breast and the ... more We wanted to present a case of neonatal mastitis and abscess caused by massage to breast and the use of foeniculum vulgare (FV) tea twice a day by mother in the literature. A 3 kg newborn boy was exclusively breastfed and had no problem in the first 10 days. Inflammation at his both breasts was discovered on 10th day, also had red blotches and tenderness together with excessive growth after the 15th day. Surface ultrasound detected hyperemic breast tissue and a 3 x 3 cm avascular echogenic area suggestive of abscess. He was hospitalised with the diagnosis of a suppurative mastitis and abscess and systemic antibiotic therapy given. Only high level of CPR and white blood cell were shown. Upon enquiry, it was found out that the mother had been drinking FV tea a few times a day since the birth of the baby in order to get rid of gas pains and increase the amount of her breast milk. It was discovered that the inflammation on breasts had been increasing since the birth of the baby and the ...
Poly(2-hydroxyethyl methacrylate) sponges doped with silver nanoparticles (Ag NP-PHEMA) were prep... more Poly(2-hydroxyethyl methacrylate) sponges doped with silver nanoparticles (Ag NP-PHEMA) were prepared by irradiation of aqueous solutions containing 2-hydroxyethyl methacrylate (HEMA) and silver nitrate in the presence of a cross-linking agent and a photoinitiator. The Ag NP-PHEMA sponges had polymer droplet morphology with interconnected pores, characteristic of PHEMA sponges prepared by polymerization-induced phase separation. The Ag NP-PHEMA sponges were yellow-brown, whereas PHEMA sponges were white. For formation of Ag NP-PHEMA, the size of the polymer droplets was larger and the rate of polymerization was increased compared to PHEMA sponges formed under similar conditions but in the absence of silver nitrate. Mechanical strength, as indicated by compression testing, was similar for Ag NP-PHEMA and PHEMA sponges. Nanoparticles slowly leached out of Ag NP-PHEMA sponges, exerting antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. Notably, Ag NPs that leached were nontoxic to human corneal epithelial (HCE-T) cells.
Purpose. Antimicrobial susceptibility is slow to determine, taking several days to fully impact t... more Purpose. Antimicrobial susceptibility is slow to determine, taking several days to fully impact treatment. This proof-of-concept study assessed the feasibility of using machine-learning techniques for analysis of data produced by the flow cytometer-assisted antimicrobial susceptibility test (FAST) method we developed. Methods. We used machine learning to assess the effect of antimicrobial agents on bacteria, comparing FAST results with broth microdilution (BMD) antimicrobial susceptibility tests (ASTs). We used Escherichia coli (1), Klebsiella pneumoniae (1) and Staphylococcus aureus (2) strains to develop the machine-learning algorithm, an expanded panel including these plus E. coli (2), K. pneumoniae (3), Proteus mirabilis (1), Pseudomonas aeruginosa (1), S. aureus (2) and Enterococcus faecalis (1), tested against FAST and BMD (Sensititre, Oxoid), then two representative isolates directly from blood cultures. Results. Our data machines defined an antibiotic-unexposed population (AUP) of bacteria, classified the FAST result by antimicrobial concentration range, and determined a concentration-dependent antimicrobial effect (CDE) to establish a predicted inhibitory concentration (PIC). Reference strains of E. coli, K. pneumoniae and S. aureus tested with different antimicrobial agents demonstrated concordance between BMD results and machine-learning analysis (CA, categoric agreement of 91 %; EA, essential agreement of 100 %). CA was achieved in 35 (83 %) and EA in 28 (67 %) by machine learning on first pass in a challenge panel of 27 Gram-negative and 15 Gram-positive ASTs. Same-day AST results were obtained from clinical E. coli (1) and S. aureus (1) isolates. Conclusions. The combination of machine learning with the FAST method generated same-day AST results and has the potential to aid early antimicrobial treatment decisions, stewardship and detection of resistance.
This study investigated aerosolized viable bacteria in a university research laboratory during op... more This study investigated aerosolized viable bacteria in a university research laboratory during operation of an acoustic-assisted flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. The aim was to assess the risk associated with use of an acoustic-assisted flow cytometer analyzing unfixed bacterial suspensions. Air sampling in a nearby clinical laboratory was conducted during the same period to provide context for the existing background of microorganisms that would be detected in the air. The three species of bacteria undergoing analysis by flow cytometer in the research laboratory were Klebsiella pneumoniae, Burkholderia thailandensis and Streptococcus pneumoniae. None of these was detected from multiple 1000 L air samples acquired in the research laboratory environment. The main cultured bacteria in both locations were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in lab...
This study investigated airborne bacteria in a university research laboratory during operation of... more This study investigated airborne bacteria in a university research laboratory during operation of an acoustic-enhanced flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. Air sampling in a nearby clinical laboratory was conducted for comparison during the same period. The three species of bacteria undergoing analysis by flow cytometry were Klebsiella pneumoniae, Burkholderia thailandensis and Streptococcus pneumoniae. These species were not detected from multiple 1000 L air samples acquired in the confined research laboratory environment. The main cultured bacteria were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in laboratory air by personnel movements during routine laboratory operation. The concentrations of bacteria detected in air samples were reduced after laboratory cleaning measures were introduced and were lower than those in a diagnostic clinical microbiology l...
In remote Aboriginal communities in Australia, scabies affects 7 out of 10 children before their ... more In remote Aboriginal communities in Australia, scabies affects 7 out of 10 children before their first birthday. This is more than six times the rate seen in the rest of the developed world. Scabies infestation is frequently complicated by bacterial infection, leading to the development of skin sores and other more serious consequences, such as septicaemia and chronic heart and kidney diseases. Tea tree oil (TTO) has been used as an antimicrobial agent for several decades with proven clinical efficacy. Preclinical investigations have demonstrated superior scabicidal properties of TTO compared with widely used scabicidal agents, such as permethrin 5% cream and ivermectin. However, current data are insufficient to warrant a broad recommendation for its use for the management of scabies because previous studies were small or limited to in vitro observations. A pragmatic first trial will examine the clinical efficacy of a simple and low-cost TTO treatment against paediatric scabies and ...
Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biol... more Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biology of bacteria within human pleural fluid has not been studied. Streptococcus pneumoniae is the most common cause of pediatric and frequent cause of adult empyema. We investigated whether S. pneumoniae can proliferate within human pleural fluid and if growth is affected by the cellular content of the fluid and/or characteristics of pneumococcal surface proteins. Invasive S. pneumoniae isolates (n = 24) and reference strain recovered from human blood or empyema were inoculated (1.5×106CFU/mL) into sterile human malignant pleural fluid samples (n = 11). All S. pneumoniae (n = 25) strains proliferated rapidly, increasing by a median of 3009 (IQR 1063-9846) from baseline at 24hrs in all pleural effusions tested. Proliferation was greater than in commercial pneumococcal culture media and concentrations were maintained for 48hrs without autolysis. A similar magnitude of proliferation was obse...
The major complication of peritoneal dialysis (PD) is the development of peritonitis, an infectio... more The major complication of peritoneal dialysis (PD) is the development of peritonitis, an infection within the abdominal cavity, primarily caused by bacteria. PD peritonitis is associated with significant morbidity, mortality and health care costs. Staphylococcus epidermidis is the most frequently isolated cause of PD-associated peritonitis. Mesothelial cells are integral to the host response to peritonitis, and subsequent clinical outcomes, yet the effects of infection on mesothelial cells are not well characterised. We systematically investigated the early mesothelial cell response to clinical and reference isolates of S. epidermidis using primary mesothelial cells and the mesothelial cell line Met-5A. Using an unbiased whole genome microarray, followed by a targeted panel of genes known to be involved in the human antibacterial response, we identified 38 differentially regulated genes (adj. p-value < 0.05) representing 35 canonical pathways after 1 hour exposure to S. epidermid...
Peritoneal dialysis exit site infections caused by Pseudomonas spp. are difficult to treat and ca... more Peritoneal dialysis exit site infections caused by Pseudomonas spp. are difficult to treat and can lead to peritonitis and/or modality failure. Effective alternative or adjunct non-antibiotic antimicrobial agents could improve treatment as well as reduce the use of antibiotics and contribute to a reduction in antibiotic selection pressure and the further development of antibiotic resistance. Vinegar is popularly promoted as a topical antimicrobial agent and has been recommended as an adjunct treatment for Pseudomonas exit site infections in PD patients. Systematic empirical data on the susceptibility of pseudomonads to vinegar are lacking. This study aimed to determine the susceptibility to vinegar of 57 isolates of Pseudomonas. The MICs and MBCs of four vinegars were determined for clinical, environmental and/or reference isolates of P. aeruginosa (n = 34), P. fluorescens (n = 11) and P. putida (n = 12) using a broth microdilution method. The MIC90 and MBC90 were also determined for each species. The MIC90 of all four vinegars against P. aeruginosa was 2% (vol/vol). The MBC90 was 8%. The MIC90 s for P. fluorescens and P. putida were also 2%. The MIC90 s were 4%. Dilutions of vinegar recommended for the treatment of Pseudomonas exit site infections have in vitro activity against these notoriously resistant bacteria. In light of increasing rates of antibiotic resistance and the need to reduce antibiotic selection pressure as part of good antibiotic stewardship, the efficacy of vinegar, or its active constituent acetic acid, for the treatment of Pseudomonas exit site infections should be investigated further.
We wanted to present a case of neonatal mastitis and abscess caused by massage to breast and the ... more We wanted to present a case of neonatal mastitis and abscess caused by massage to breast and the use of foeniculum vulgare (FV) tea twice a day by mother in the literature. A 3 kg newborn boy was exclusively breastfed and had no problem in the first 10 days. Inflammation at his both breasts was discovered on 10th day, also had red blotches and tenderness together with excessive growth after the 15th day. Surface ultrasound detected hyperemic breast tissue and a 3 x 3 cm avascular echogenic area suggestive of abscess. He was hospitalised with the diagnosis of a suppurative mastitis and abscess and systemic antibiotic therapy given. Only high level of CPR and white blood cell were shown. Upon enquiry, it was found out that the mother had been drinking FV tea a few times a day since the birth of the baby in order to get rid of gas pains and increase the amount of her breast milk. It was discovered that the inflammation on breasts had been increasing since the birth of the baby and the ...
Poly(2-hydroxyethyl methacrylate) sponges doped with silver nanoparticles (Ag NP-PHEMA) were prep... more Poly(2-hydroxyethyl methacrylate) sponges doped with silver nanoparticles (Ag NP-PHEMA) were prepared by irradiation of aqueous solutions containing 2-hydroxyethyl methacrylate (HEMA) and silver nitrate in the presence of a cross-linking agent and a photoinitiator. The Ag NP-PHEMA sponges had polymer droplet morphology with interconnected pores, characteristic of PHEMA sponges prepared by polymerization-induced phase separation. The Ag NP-PHEMA sponges were yellow-brown, whereas PHEMA sponges were white. For formation of Ag NP-PHEMA, the size of the polymer droplets was larger and the rate of polymerization was increased compared to PHEMA sponges formed under similar conditions but in the absence of silver nitrate. Mechanical strength, as indicated by compression testing, was similar for Ag NP-PHEMA and PHEMA sponges. Nanoparticles slowly leached out of Ag NP-PHEMA sponges, exerting antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. Notably, Ag NPs that leached were nontoxic to human corneal epithelial (HCE-T) cells.
Purpose. Antimicrobial susceptibility is slow to determine, taking several days to fully impact t... more Purpose. Antimicrobial susceptibility is slow to determine, taking several days to fully impact treatment. This proof-of-concept study assessed the feasibility of using machine-learning techniques for analysis of data produced by the flow cytometer-assisted antimicrobial susceptibility test (FAST) method we developed. Methods. We used machine learning to assess the effect of antimicrobial agents on bacteria, comparing FAST results with broth microdilution (BMD) antimicrobial susceptibility tests (ASTs). We used Escherichia coli (1), Klebsiella pneumoniae (1) and Staphylococcus aureus (2) strains to develop the machine-learning algorithm, an expanded panel including these plus E. coli (2), K. pneumoniae (3), Proteus mirabilis (1), Pseudomonas aeruginosa (1), S. aureus (2) and Enterococcus faecalis (1), tested against FAST and BMD (Sensititre, Oxoid), then two representative isolates directly from blood cultures. Results. Our data machines defined an antibiotic-unexposed population (AUP) of bacteria, classified the FAST result by antimicrobial concentration range, and determined a concentration-dependent antimicrobial effect (CDE) to establish a predicted inhibitory concentration (PIC). Reference strains of E. coli, K. pneumoniae and S. aureus tested with different antimicrobial agents demonstrated concordance between BMD results and machine-learning analysis (CA, categoric agreement of 91 %; EA, essential agreement of 100 %). CA was achieved in 35 (83 %) and EA in 28 (67 %) by machine learning on first pass in a challenge panel of 27 Gram-negative and 15 Gram-positive ASTs. Same-day AST results were obtained from clinical E. coli (1) and S. aureus (1) isolates. Conclusions. The combination of machine learning with the FAST method generated same-day AST results and has the potential to aid early antimicrobial treatment decisions, stewardship and detection of resistance.
This study investigated aerosolized viable bacteria in a university research laboratory during op... more This study investigated aerosolized viable bacteria in a university research laboratory during operation of an acoustic-assisted flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. The aim was to assess the risk associated with use of an acoustic-assisted flow cytometer analyzing unfixed bacterial suspensions. Air sampling in a nearby clinical laboratory was conducted during the same period to provide context for the existing background of microorganisms that would be detected in the air. The three species of bacteria undergoing analysis by flow cytometer in the research laboratory were Klebsiella pneumoniae, Burkholderia thailandensis and Streptococcus pneumoniae. None of these was detected from multiple 1000 L air samples acquired in the research laboratory environment. The main cultured bacteria in both locations were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in lab...
This study investigated airborne bacteria in a university research laboratory during operation of... more This study investigated airborne bacteria in a university research laboratory during operation of an acoustic-enhanced flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. Air sampling in a nearby clinical laboratory was conducted for comparison during the same period. The three species of bacteria undergoing analysis by flow cytometry were Klebsiella pneumoniae, Burkholderia thailandensis and Streptococcus pneumoniae. These species were not detected from multiple 1000 L air samples acquired in the confined research laboratory environment. The main cultured bacteria were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in laboratory air by personnel movements during routine laboratory operation. The concentrations of bacteria detected in air samples were reduced after laboratory cleaning measures were introduced and were lower than those in a diagnostic clinical microbiology l...
In remote Aboriginal communities in Australia, scabies affects 7 out of 10 children before their ... more In remote Aboriginal communities in Australia, scabies affects 7 out of 10 children before their first birthday. This is more than six times the rate seen in the rest of the developed world. Scabies infestation is frequently complicated by bacterial infection, leading to the development of skin sores and other more serious consequences, such as septicaemia and chronic heart and kidney diseases. Tea tree oil (TTO) has been used as an antimicrobial agent for several decades with proven clinical efficacy. Preclinical investigations have demonstrated superior scabicidal properties of TTO compared with widely used scabicidal agents, such as permethrin 5% cream and ivermectin. However, current data are insufficient to warrant a broad recommendation for its use for the management of scabies because previous studies were small or limited to in vitro observations. A pragmatic first trial will examine the clinical efficacy of a simple and low-cost TTO treatment against paediatric scabies and ...
Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biol... more Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biology of bacteria within human pleural fluid has not been studied. Streptococcus pneumoniae is the most common cause of pediatric and frequent cause of adult empyema. We investigated whether S. pneumoniae can proliferate within human pleural fluid and if growth is affected by the cellular content of the fluid and/or characteristics of pneumococcal surface proteins. Invasive S. pneumoniae isolates (n = 24) and reference strain recovered from human blood or empyema were inoculated (1.5×106CFU/mL) into sterile human malignant pleural fluid samples (n = 11). All S. pneumoniae (n = 25) strains proliferated rapidly, increasing by a median of 3009 (IQR 1063-9846) from baseline at 24hrs in all pleural effusions tested. Proliferation was greater than in commercial pneumococcal culture media and concentrations were maintained for 48hrs without autolysis. A similar magnitude of proliferation was obse...
The major complication of peritoneal dialysis (PD) is the development of peritonitis, an infectio... more The major complication of peritoneal dialysis (PD) is the development of peritonitis, an infection within the abdominal cavity, primarily caused by bacteria. PD peritonitis is associated with significant morbidity, mortality and health care costs. Staphylococcus epidermidis is the most frequently isolated cause of PD-associated peritonitis. Mesothelial cells are integral to the host response to peritonitis, and subsequent clinical outcomes, yet the effects of infection on mesothelial cells are not well characterised. We systematically investigated the early mesothelial cell response to clinical and reference isolates of S. epidermidis using primary mesothelial cells and the mesothelial cell line Met-5A. Using an unbiased whole genome microarray, followed by a targeted panel of genes known to be involved in the human antibacterial response, we identified 38 differentially regulated genes (adj. p-value < 0.05) representing 35 canonical pathways after 1 hour exposure to S. epidermid...
Peritoneal dialysis exit site infections caused by Pseudomonas spp. are difficult to treat and ca... more Peritoneal dialysis exit site infections caused by Pseudomonas spp. are difficult to treat and can lead to peritonitis and/or modality failure. Effective alternative or adjunct non-antibiotic antimicrobial agents could improve treatment as well as reduce the use of antibiotics and contribute to a reduction in antibiotic selection pressure and the further development of antibiotic resistance. Vinegar is popularly promoted as a topical antimicrobial agent and has been recommended as an adjunct treatment for Pseudomonas exit site infections in PD patients. Systematic empirical data on the susceptibility of pseudomonads to vinegar are lacking. This study aimed to determine the susceptibility to vinegar of 57 isolates of Pseudomonas. The MICs and MBCs of four vinegars were determined for clinical, environmental and/or reference isolates of P. aeruginosa (n = 34), P. fluorescens (n = 11) and P. putida (n = 12) using a broth microdilution method. The MIC90 and MBC90 were also determined for each species. The MIC90 of all four vinegars against P. aeruginosa was 2% (vol/vol). The MBC90 was 8%. The MIC90 s for P. fluorescens and P. putida were also 2%. The MIC90 s were 4%. Dilutions of vinegar recommended for the treatment of Pseudomonas exit site infections have in vitro activity against these notoriously resistant bacteria. In light of increasing rates of antibiotic resistance and the need to reduce antibiotic selection pressure as part of good antibiotic stewardship, the efficacy of vinegar, or its active constituent acetic acid, for the treatment of Pseudomonas exit site infections should be investigated further.
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Papers by Christine Carson