Description:
Acinetobacter spp. are increasingly reported as important causes of human infection. Many isolates exhibit multi-drug resistance, raising concerns over our ability to treat serious infections with these organisms. The impact of infection on clinical outcome as well as the importance of multi-drug resistance is poorly defined. A descriptive retrospective observational study was undertaken of all episodes of Acinetobacter bacteremia occurring in a UK tertiary care centre from 1998-2006. Demographics of infected patients, characteristics and antimicrobial susceptibility of infecting strains were recorded and the impact of antimicrobial therapy on all causes of 30-day mortality assessed. Three hundred ninety-nine episodes of Acinetobacter bacteremia were identified, with A. baumannii being the most frequently isolated species. Most episodes occurred in critical care and were associated with multidrug resistance, with carbapenem resistance rising from 0% in 1998 to 55% in 2006. Although bacteremia due to carbapenem-resistant Acinetobacter and a requirement for critical care were associated with a higher mortality, mortality was not reduced by the administration of appropriate empirical antimicrobial therapy. A prospective study is required to identify both the most effective intervention and those most likely to benefit from treatment.
Description:
Background: Escherichia coli is the commonest cause of community and nosocomial urinary tract infection (UTI). Antibiotic treatment is usually empirical relying on susceptibility data from local surveillance studies. We therefore set out to determine levels of resistance to 8 commonly used antimicrobial agents amongst all urinary isolates obtained over a 12 month period. Methods: Antimicrobial susceptibility to ampicillin, amoxicillin/ clavulanate, cefalexin, ciprofloxacin, gentamicin, nitrofurantoin, trimethoprim and cefpodoxime was determined for 11,865 E. coli urinary isolates obtained from community and hospitalised patients in East London. Results: Nitrofurantoin was the most active agent (94% susceptible), followed by gentamicin and cefpodoxime. High rates of resistance to ampicillin (55%) and trimethoprim (40%), often in combination were observed in both sets of isolates. Although isolates exhibiting resistance to multiple drug classes were rare, resistance to cefpodoxime, indicative of Extended spectrum
Description:
Background: Escherichia coli is the commonest cause of community and nosocomial urinary tract infection (UTI). Antibiotic treatment is usually empirical relying on susceptibility data from local surveillance studies. We therefore set out to determine levels of resistance to 8 commonly used antimicrobial agents amongst all urinary isolates obtained over a 12 month period. Methods: Antimicrobial susceptibility to ampicillin, amoxicillin/ clavulanate, cefalexin, ciprofloxacin, gentamicin, nitrofurantoin, trimethoprim and cefpodoxime was determined for 11,865 E. coli urinary isolates obtained from community and hospitalised patients in East London. Results: Nitrofurantoin was the most active agent (94% susceptible), followed by gentamicin and cefpodoxime. High rates of resistance to ampicillin (55%) and trimethoprim (40%), often in combination were observed in both sets of isolates. Although isolates exhibiting resistance to multiple drug classes were rare, resistance to cefpodoxime, indicative of Extended spectrum
Description:
Objectives The efflux inhibitor 1-(1-naphthylmethyl)-piperazine (NMP) has been demonstrated to reverse multidrug resistance in Acinetobacter baumannii. We investigated the interaction of NMP with tigecycline and three other tetracyclines on clinical isolates of A. baumannii. Methods One hundred and four clinical isolates of Acinetobacter were tested for susceptibility to tigecycline, minocycline, doxycycline and tetracycline by disc diffusion, and tigecycline MICs were determined by Etest, both in the presence and absence of NMP. Tigecycline MICs and zones of inhibition were interpreted using the BSAC guidelines. An OXA carbapenemase multiplex PCR was also performed on each isolate. Results Mean zones of inhibition for tetracycline, doxycycline and minocycline increased by 11.3%, 22.9% and 11.2%, respectively, in the presence of NMP. In contrast, tigecycline susceptibility was decreased in the presence of NMP, with mean zones of inhibition decreasing by 8.4%. Based on PCR results, all but six isolates belonged to the OXA-23 clone 1. Conclusions Susceptibility to tigecycline of the A. baumannii OXA-23 clone 1 prevalent in the UK is reduced (∼2-fold) by the presence of the efflux inhibitor NMP. NMP does not have the same effect on susceptibility to other tetracyclines.
Description:
Introduction: Significant effort has been invested in looking at the antimicrobial activity of plant extracts from tropical regions of Australia, with less interest in those from more temperate environments. We sought to redress this imbalance by examining antimicrobial activities of extracts from native plants of Victoria. Methods: Sixteen plant samples were obtained around the Ballarat region of Victoria. Plant material was desiccated, ground and extracted with methanol at room temperature. Methanol extracts were subsequently dissolved in water, filtered and freeze dried. Extracts were dissolved in water and their activity determined against eight bacterial species. Plant extracts that showed appreciable antibacterial activity in the initial antimicrobial screen were examined further with both their MICs and MBCs determined. Results: Ten of the sixteen plant extracts showed antimicrobial activity. Extracts of Eucalyptus, Melaleuca, Prostanthera and Westringia were particularly active with MICs as low as 0.25 mg/ml against organisms including P. aeruginosa and S. aureus. Conclusion: The current study demonstrates the antimicrobial activity of plant extracts from temperate Australia. These may serve as precursors for future chemotherapy agents.
Description:
Introduction: Significant effort has been invested in looking at the antimicrobial activity of plant extracts from tropical regions of Australia, with less interest in those from more temperate environments. We sought to redress this imbalance by examining antimicrobial activities of extracts from native plants of Victoria. Methods: Sixteen plant samples were obtained around the Ballarat region of Victoria. Plant material was desiccated, ground and extracted with methanol at room temperature. Methanol extracts were subsequently dissolved in water, filtered and freeze dried. Extracts were dissolved in water and their activity determined against eight bacterial species. Plant extracts that showed appreciable antibacterial activity in the initial antimicrobial screen were examined further with both their MICs and MBCs determined. Results: Ten of the sixteen plant extracts showed antimicrobial activity. Extracts of Eucalyptus, Melaleuca, Prostanthera and Westringia were particularly active with MICs as low as 0.25 mg/ml against organisms including P. aeruginosa and S. aureus. Conclusion: The current study demonstrates the antimicrobial activity of plant extracts from temperate Australia. These may serve as precursors for future chemotherapy agents.
Description:
Confectionary products are often considered relatively inert from a microbiological perspective. Nevertheless, several Salmonella outbreaks have been attributed to confectionary, particularly chocolate products. The cause of these outbreaks was generally traced back to lapses in GMP, particularly cross contact issues and water ingress. Managing Salmonella in chocolate manufacture begins with a validated cocoa bean-roasting process. However, the potential for pathogen recontamination exists with the addition of ingredients and inclusions post process. This risk can be managed by a stringent supplier assurance program including prerelease microbiological testing of these materials. In addition to assured ingredients, the manufacturing environment must include a strict containment policy for raw and finished goods, control of water use including the prevention of water leaks, and ongoing microbial surveillance. Manufacturing equipment needs to be hygienically designed and amenable to sanitation processes, should a contamination event occur. Lastly, an effective microbiological verification program is essential to ensure all described processes are in control.
Description:
Birds can spread microorganisms through their movement; however, it is still not fully understood how wild birds acquire and disperse antimicrobial-resistant (AMR) bacteria. We sampled wild Australian birds from three geographically distinct locations for the presence of AMR strains of two clinically important species of bacteria, Escherichia coli and Enterococcus spp. A total of 121 birds were sampled, representing 15 different species. Thirty E. coli and 54 Enterococcus isolates were tested for resistance to 12 and 8 different antibiotics, respectively. Resistance to at least one antibiotic was common, being detected in 96% of Enterococcus and 60% of E. coli isolates. The vancomycin-resistance genes vanA and vanD were detected in 22% of enterococci (13% vanA, 9% vanD), while 9% displayed phenotypic resistance with no associated gene. Wild birds are a carrier of AMR bacteria in Australia, and are capable of harbouring a more diverse range of vancomycin-resistance genes than is typically seen among Australian clinical isolates.
Description:
Birds can spread microorganisms through their movement; however, it is still not fully understood how wild birds acquire and disperse antimicrobial-resistant (AMR) bacteria. We sampled wild Australian birds from three geographically distinct locations for the presence of AMR strains of two clinically important species of bacteria, Escherichia coli and Enterococcus spp. A total of 121 birds were sampled, representing 15 different species. Thirty E. coli and 54 Enterococcus isolates were tested for resistance to 12 and 8 different antibiotics, respectively. Resistance to at least one antibiotic was common, being detected in 96% of Enterococcus and 60% of E. coli isolates. The vancomycin-resistance genes vanA and vanD were detected in 22% of enterococci (13% vanA, 9% vanD), while 9% displayed phenotypic resistance with no associated gene. Wild birds are a carrier of AMR bacteria in Australia, and are capable of harbouring a more diverse range of vancomycin-resistance genes than is typically seen among Australian clinical isolates.
Description:
Sir, MDR Gram-negative bacteria are identified as critical pathogens and their effective treatment increasingly relies on the polymyxins (polymyxin B, colistin), either alone or as part of unorthodox combination therapies.1 The rapid emergence of polymyxin resistance due to mutations/insertions in genes involved in LPS modifications (lpxCAD, pmrA/B, mgrB, phoP/Q, ccrAB) has been reported among individuals exposed to or treated with polymyxins.1Of greater concern are increasing reports of resistance due to the acquisition of phosphoethanolamine (PEtN) transferases, enzymes that catalyse the addition of phosphoethanolamine to lipid A, resulting in lower binding affinity of polymyxins.1 Since the first identification in China,1 multiple gene variants have been reported in diverse bacterial genera recovered from a range of human, retail food, foodproducing animal and environmental sources.2 Here, we report a novel variant of PEtN transferase, designated MCR-1.8, and its genetic context in an MDR Escherichia coli isolate recovered from poultry in Brunei Darussalam.
Description:
Sir, MDR Gram-negative bacteria are identified as critical pathogens and their effective treatment increasingly relies on the polymyxins (polymyxin B, colistin), either alone or as part of unorthodox combination therapies.1 The rapid emergence of polymyxin resistance due to mutations/insertions in genes involved in LPS modifications (lpxCAD, pmrA/B, mgrB, phoP/Q, ccrAB) has been reported among individuals exposed to or treated with polymyxins.1Of greater concern are increasing reports of resistance due to the acquisition of phosphoethanolamine (PEtN) transferases, enzymes that catalyse the addition of phosphoethanolamine to lipid A, resulting in lower binding affinity of polymyxins.1 Since the first identification in China,1 multiple gene variants have been reported in diverse bacterial genera recovered from a range of human, retail food, foodproducing animal and environmental sources.2 Here, we report a novel variant of PEtN transferase, designated MCR-1.8, and its genetic context in an MDR Escherichia coli isolate recovered from poultry in Brunei Darussalam.
Description:
During food manufacturing, the potential exists for contamination of products with pathogenic microorganisms. While the ingestion of a bacterial pathogen will typically result in illness in a susceptible host, it is not the case for each strain within a given species. Pathogenic bacteria display various levels of host specificity: some infect a wide range of hosts, while others have strict host selectivity and are obligate pathogens. Host specificity of bacterial pathogens is determined by multiple molecular interactions between both the pathogens and their hosts. Understanding these interactions in detail will allow risk-based decisions to be made on affected foods, informed by knowledge of specific strains or pathotypes. This has the potential to avoid costly and unnecessary recalls with classical pathogens that can be proved to have a low potential for causing illness.
Presence and antimicrobial resistance profiles of Escherichia coli, Enterococcusspp. and Salmonellasp. in 12 species of Australian shorebirds and terns