title: Cracking the resistance of non-tuberculosis mycobacterium against existing antibiotics

authors: Hodson, Callie Jane

subjects: Mycobacterium

abstract: Mycobacterium avium (M. avium) is quickly becoming the most prevalent Mycobacterium infection in western countries. M. avium is an opportunistic pulmonary pathogen, infecting patients who often are vulnerable due to existing medical conditions. Antibiotic therapy of M. avium is long (generally 18 months) and often unsuccessful at eliminating the infection, promoting resistance to commonly used antibiotics, such as clarithromycin. 
M. avium exists as a biofilm in lung infections, adding to the difficulty in eradicating the infection. My research investigated potential M. avium biofilm dispersing agents, as well as antibiotic synergy for improved M. avium eradication.
Our findings show that ten clinically isolated M. avium samples were all highly resistant (>16μg/mL) to antibiotics commonly used in the treatment of M. avium infections, both in planktonic and biofilm phenotypes. Some isolates were found to have MICs of >128μg/mL.
M. avium isolates differed in biofilm phenotype, and correspondingly, their susceptibility to antibiotics and potential biofilm dispersing agents. 
No antibiotics tested during this research had significant bactericidal or bacteriostatic action on any M. avium isolates, in planktonic or biofilm phenotype.  
The addition of 3.6mg/mL aspirin (acetylsalicylic acid) or 3.6mg/mL ibuprofen to planktonic and biofilm cells showed significant increase in M. avium cell death. Previously identified biofilm dispersing agents, such as mannitol, N-acetyl-L-cysteine, active manuka honey, methylglyoxal, Lipitor®, 2,4-dinitrophenol and EDTA,  had no significant effect on dispersing M. avium biofilms or increasing their susceptibility to antibiotics. A concentrations of 4mg/mL aspirin combined with 8mg/mL of EDTA had significant effects, sterilizing and completely eradicating in vitro three week old mature M. avium biofilms.
Future work should be conducted into the specific pathways aspirin and ibuprofen effect. Furthermore, development of effective agonists/antagonists of those pathways to disperse M. avium biofilms should be researched. Research into improved and novel Mycobacterial antibiotics are needed to develop drugs capable of successfully treating M. avium infections.

text: Cracking the resistance of non-tuberculosis mycobacterium against existing antibiotics Mycobacterium avium (M. avium) is quickly becoming the most prevalent Mycobacterium infection in western countries. M. avium is an opportunistic pulmonary pathogen, infecting patients who often are vulnerable due to existing medical conditions. Antibiotic therapy of M. avium is long (generally 18 months) and often unsuccessful at eliminating the infection, promoting resistance to commonly used antibiotics, such as clarithromycin. 
M. avium exists as a biofilm in lung infections, adding to the difficulty in eradicating the infection. My research investigated potential M. avium biofilm dispersing agents, as well as antibiotic synergy for improved M. avium eradication.
Our findings show that ten clinically isolated M. avium samples were all highly resistant (>16μg/mL) to antibiotics commonly used in the treatment of M. avium infections, both in planktonic and biofilm phenotypes. Some isolates were found to have MICs of >128μg/mL.
M. avium isolates differed in biofilm phenotype, and correspondingly, their susceptibility to antibiotics and potential biofilm dispersing agents. 
No antibiotics tested during this research had significant bactericidal or bacteriostatic action on any M. avium isolates, in planktonic or biofilm phenotype.  
The addition of 3.6mg/mL aspirin (acetylsalicylic acid) or 3.6mg/mL ibuprofen to planktonic and biofilm cells showed significant increase in M. avium cell death. Previously identified biofilm dispersing agents, such as mannitol, N-acetyl-L-cysteine, active manuka honey, methylglyoxal, Lipitor®, 2,4-dinitrophenol and EDTA,  had no significant effect on dispersing M. avium biofilms or increasing their susceptibility to antibiotics. A concentrations of 4mg/mL aspirin combined with 8mg/mL of EDTA had significant effects, sterilizing and completely eradicating in vitro three week old mature M. avium biofilms.
Future work should be conducted into the specific pathways aspirin and ibuprofen effect. Furthermore, development of effective agonists/antagonists of those pathways to disperse M. avium biofilms should be researched. Research into improved and novel Mycobacterial antibiotics are needed to develop drugs capable of successfully treating M. avium infections.

year: 2015

title: Does ‘acoustic anchoring’ reduce post-translocation dispersal of North Island robins?

authors: Bradley, David William

subjects: acoustic anchoring

abstract: Context: Animal translocations are an important conservation tool; however, post-release dispersal can hinder successful population establishment. Playback of conspecific song attracts dispersing individuals in some species, although its application following animal translocation has yet to be rigorously investigated.

Aims: To determine whether conspecific song can be used as an ‘acoustic anchor’, we adopted an experimental approach during the translocation of 60 North Island robins (Petroica longipes).
Methods: At one of two release locations, we broadcast song at natural rates from four speakers (4 h per morning), for 9 days following release; we set the second release location as a control where identical conditions were established but no playback occurred. To assess the impact of playback, we monitored speaker and control locations, surveyed tracks around the release areas, and radio-tracked robins over nine playback days and an additional 9 days.
Key results: Most robins left both immediate release areas; however, our results showed that (1) more robins (6 birds on 14 of the 18 days), in particular females (3 birds), approached the playback location than the ‘flagged’ control location (3 male birds on 5 of the 18 days), (2) individual robins returned to the playback location repeatedly, unlike those at the control site, and (3) robins also visited the playback location longer after playback than they did silent control locations. In contrast, radio-telemetry data from five robins suggested that general dispersal was not influenced by playback. Two radio-tracked females moved over long distances (some to >3 km from their release location), whereas two radio-tracked males remained relatively close to the release sites.
Conclusions: We demonstrated a short-term attraction effect of playback over a period of several weeks for some birds, particularly females. In contrast, we detected fewer birds over a shorter period at the silent control release site, where no females were detected. However, long-term monitoring at both sites suggested that the effect of playback on reducing post-release dispersal was transitory.
Implications: The lack of a clear and lasting effect of acoustic anchoring on dispersal in the present study has provided information on the limited utility of song playback as a conservation management tool for this species. Consideration of the species’ ecology and suitability for ‘acoustic anchoring’ must be made before playback is employed as a conservation measure to reduce excess post-translocation dispersal.

text: Does ‘acoustic anchoring’ reduce post-translocation dispersal of North Island robins? Context: Animal translocations are an important conservation tool; however, post-release dispersal can hinder successful population establishment. Playback of conspecific song attracts dispersing individuals in some species, although its application following animal translocation has yet to be rigorously investigated.

Aims: To determine whether conspecific song can be used as an ‘acoustic anchor’, we adopted an experimental approach during the translocation of 60 North Island robins (Petroica longipes).
Methods: At one of two release locations, we broadcast song at natural rates from four speakers (4 h per morning), for 9 days following release; we set the second release location as a control where identical conditions were established but no playback occurred. To assess the impact of playback, we monitored speaker and control locations, surveyed tracks around the release areas, and radio-tracked robins over nine playback days and an additional 9 days.
Key results: Most robins left both immediate release areas; however, our results showed that (1) more robins (6 birds on 14 of the 18 days), in particular females (3 birds), approached the playback location than the ‘flagged’ control location (3 male birds on 5 of the 18 days), (2) individual robins returned to the playback location repeatedly, unlike those at the control site, and (3) robins also visited the playback location longer after playback than they did silent control locations. In contrast, radio-telemetry data from five robins suggested that general dispersal was not influenced by playback. Two radio-tracked females moved over long distances (some to >3 km from their release location), whereas two radio-tracked males remained relatively close to the release sites.
Conclusions: We demonstrated a short-term attraction effect of playback over a period of several weeks for some birds, particularly females. In contrast, we detected fewer birds over a shorter period at the silent control release site, where no females were detected. However, long-term monitoring at both sites suggested that the effect of playback on reducing post-release dispersal was transitory.
Implications: The lack of a clear and lasting effect of acoustic anchoring on dispersal in the present study has provided information on the limited utility of song playback as a conservation management tool for this species. Consideration of the species’ ecology and suitability for ‘acoustic anchoring’ must be made before playback is employed as a conservation measure to reduce excess post-translocation dispersal.

year: 2011

title: Potential science tools to support mahinga kai decision-making in freshwater management

authors: Collier, Kevin J.

subjects: mahinga kai

abstract: Mahinga kai is a key value for freshwater management that needs to be articulated in objective setting for environmental limits in the National Objectives Framework (NOF). Mahinga kai generally refers to indigenous freshwater species that have traditionally been used for food, tools or other resources. Many mahinga kai sites, both current and historical, are in lowland settings where freshwater environments are often in a degraded state and values are correspondingly compromised. With limited availability of sites in good condition within rohe to help define desired states for mahinga kai, alternative approaches are needed to establish condition bands for management. In particular, tools that assist with envisaging desired states and predicting environmental changes required to sustain those states will help communities and tangata whenua set management objectives. To achieve this effectively an approach is required that utilises Mātauranga Māori and science tools

text: Potential science tools to support mahinga kai decision-making in freshwater management Mahinga kai is a key value for freshwater management that needs to be articulated in objective setting for environmental limits in the National Objectives Framework (NOF). Mahinga kai generally refers to indigenous freshwater species that have traditionally been used for food, tools or other resources. Many mahinga kai sites, both current and historical, are in lowland settings where freshwater environments are often in a degraded state and values are correspondingly compromised. With limited availability of sites in good condition within rohe to help define desired states for mahinga kai, alternative approaches are needed to establish condition bands for management. In particular, tools that assist with envisaging desired states and predicting environmental changes required to sustain those states will help communities and tangata whenua set management objectives. To achieve this effectively an approach is required that utilises Mātauranga Māori and science tools

year: 2014