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As sequencing and data analysis methods improve and more bacterial species are identified, microbial profiling has been performed more widely in marine species. To enable the development of potential prophylactic strategies against bacterial disease in abalone induced by elevated water temperatures, the left kidney and stomach samples of six unaffected adult greenlip abalone Haliotis laevigata were sampled in summer and winter to enable comparisons of endogenous abalone microbial profiles. Under the experimental conditions, needle aspiration of selected tissues did not allow collection of adequate amounts of abalone tissue for microbiome studies. Tenericutes, Proteobacteria and Fusobacteria were the three major phyla present in most samples which were previously identified in other marine species. Propionibacterium, Psychrilyobacter, Pseudoruegeria, Ruegeria, Arcobacter, Shewanella, Pseudoalteromonas, Streptococcus and Mycoplasma were the nine genera that were detected in 0.5% or more of all samples. The beta-diversity results indicated there were significant differences between summer and winter samples. The microbiome structures were different between left kidney and stomach samples. It was found that the abalone left kidney harboured diverse bacteria and was a potential indicator of the physiological status of the abalone, offering an alternative site for microbial profiling of abalone, apart from the gastrointestinal tract. Refereed/Peer-reviewed

It is known that gilt progeny performance is reduced compared with sow progeny. Previous research suggests that the presence of maternal feces in early life improves the health and survival of offspring. Therefore, we aimed to determine whether contact with feces from multiparous (MP) sows would improve the growth and survival of piglets born and reared on primiparous (P1) sows and if so, whether these differences are associated with the gut microbiota. Four treatments were applied for 10 days: Donor (n = 29) piglets had limited access to maternal feces as, each morning, sow feces were removed and placed in the crate of a P1 sow (P1-FT; n = 30 piglets) and P1-Con (n = 29) and MP-Con (n = 33) piglets had access to their own mothers’ feces. All piglets were weighed on days 1, 3, 10, and 18. Fecal samples were collected from a subset of sows (n = 10/treatment) 3 days post farrow and from two female piglets/litter on days 10 and 18 (n = 20/treatment) and subject to 16S rRNA amplicon analysis. Escherichia, Clostridium, Campylobacter, and Treponema were more abundant in MP sows, while P1 sows had a higher abundance of Lactobacillus and Prevotella. At 10 days, P1 progeny fecal microbiota differed, and growth and survival were reduced when compared with MP progeny. No treatment effect was observed for P1-FT piglets (P > 0.05). Donor piglets had a different fecal microbiota and improved weight and survival then all other treatments (P < 0.05). Overall, the removal of sow feces from the farrowing crate improved piglet microbiota development, growth, and survival.

Initial enteric microbial colonisation influences animal health and disease, hence an understanding of the first microbial colonisers within the piglet is important. The spiral colon of piglets that were stillborn (n = 20), born-alive (n = 10), and born alive and had sucked (n = 9) were collected from 28 sows to investigate whether initial microbial colonisation occurs pre- or post-partum and how it develops during the first 24 h post-partum. To examine this, DNA was extracted and 16S rRNA amplicon analysis was performed to allow analysis of microbial communities. The results indicate that microbial colonisation of the spiral colon had occurred in stillborn pigs, suggesting microbial exposure prior to birth. Alpha diversity metrics indicated that the number of taxa and community richness were higher in piglets that sucked (p < 0.001) and community evenness was lower in stillborns in comparison to born-alive (p < 0.001) but was not affected by colostrum consumption (p < 0.001). Additionally, when compared with stillborn piglets, the bacteria colonising the spiral colon during the first 24 h post-partum included the potentially pathogenic bacteria Escherichia coli, Clostridium perfringens and Clostridium celatum, and potentially beneficial bacteria Lactobacillus reutueri and Faecalibacterium prausnitzii. The relative presence of Archaea was high in stillborn piglets but decreased with post-natal environmental exposure. It is evident that stillborn piglets have bacteria present within their spiral colon, however further studies are needed in order to determine the time at which colonisation is initiated and the mechanisms determining how colonisation occurs. Additionally, as expected, the immediate post-natal environment largely influences the microorganisms colonising, while colostrum consumption further contributes to the microbial community enrichment.

Weaning is a stressful time for piglets, often leading to weight loss and is associated with increased morbidity and mortality. A leading cause for these post-weaning problems is enteric dysbiosis and methods to improve piglet health at this crucial developmental stage are needed. This study aimed to determine whether an enteric dysbiosis caused by weaning could be corrected via a faecal microbiota transplantation (FMT) from healthy piglets from a previous wean. Two or four focal piglets per litter were assigned to one of two treatments; FMT two days post weaning (n = 21; FMT) or a control which received saline two days post weaning (n = 21; CON). FMT consisted of homogenised donor faeces administered orally at 3 mL/kg. Weaning occurred at 18 days of age and weights and faecal samples were collected on days 18, 20, 24 and 35. 16S rRNA amplicon analysis was used to assess the faecal microbiota of piglets. FMT increased Shannon’s diversity post weaning (p < 0.001) and reduced the scratch score observed at 24 days of age (p < 0.001). The bacterial populations significantly differed in composition at each taxonomic level. In FMT pigs, significant increases in potentially pathogenic Escherichia coli were observed. However, increases in beneficial bacteria Lactobacillus mucosae and genera Fibrobacteres and Bacteroidetes were also observed in FMT treated animals. To our knowledge, this is the first study to observe a significant effect on piglet faecal microbiota following a single FMT administered post weaning. Therefore, FMT post weaning can potentially alleviate enteric dysbiosis.

Gram-negative bacteria are known to cause severe infections in both humans and animals. Antimicrobial resistance (AMR) in Gram-negative bacteria is a major challenge in the treatment of clinical infections globally due to the propensity of these organisms to rapidly develop resistance against antimicrobials in use. In addition, Gram-negative bacteria possess highly efficient mechanisms through which the AMR can be disseminated between pathogenic and commensal bacteria of the same or different species. These unique traits of Gram-negative bacteria have resulted in evolution of Gram-negative bacterial strains demonstrating resistance to multiple classes of antimicrobials. The evergrowing resistance issue has not only resulted in limitation of treatment options but also led to increased treatment costs and mortality rates in humans and animals. With few or no new antimicrobials in production to combat severe life-threatening infections, AMR has been described as the one of the most severe, long-term threats to human health. Aside from overuse and misuse of antimicrobials in humans, another factor that has exacerbated the emergence of AMR in Gram-negative bacteria is the veterinary use of antimicrobials that belong to the same classes considered to be critically important for treating serious life-threatening infections in humans. Despite the fact that development of AMR dates back to before the introduction of antimicrobials, the recent surge in the resistance towards all available critically important antimicrobials has emerged as a major public health issue. This review thus focuses on discussing the development, transmission and public health impact of AMR in Gram-negative bacteria in animals. Refereed/Peer-reviewed

Globally, gulls have been associated with carriage of high levels of Escherichia coli strains resistant to critically important antimicrobials (CIAs), a major concern, as these antimicrobials are the sole alternative or one among only a few alternatives available to treat severe life-threatening infections in humans. Previous studies of Australian silver gulls demonstrated high levels of resistance to CIAs, particularly fluoroquinolone and extended-spectrum cephalosporins, among E. coli strains (carriage at 24% and 22%, respectively). This study aimed to identify and characterize strains from four distinct bird species inhabiting a common coastal environment, determine the frequency of carriage of CIA-resistant E. coli strains, and examine if these resistant clones and their resistance-encoding mobile genetic elements (MGEs) could be transmitted between species. CIA-resistant E. coli was detected in silver gulls (53%), little penguins (11%), and feral pigeons (10%), but not in bridled terns. In total, 37 different sequence types (STs) were identified, including clinically significant human-associated lineages, such as ST131, ST95, ST648, ST69, ST540, ST93, ST450, and ST10. Five main mobile genetic elements associated with blaCTX-M-positive E. coli strains isolated from three bird species were detected. Examination of clonal lineages and MGEs provided indirect evidence of transfer of resistance between bird species. The carriage of CIA-resistant E. coli by gulls and pigeons with proximity to humans, and in some instances food-producing animals, increases the likelihood of further bidirectional dissemination. IMPORTANCE It has been shown that 20% of Australian silver gulls carry drug-resistant Escherichia coli strains of anthropogenic origin associated with severe diseases, such as sepsis and urinary tract infections, in humans. To further characterize the dynamics of drug-resistant E. coli in wildlife populations, we investigated the carriage of critically important antimicrobial (CIA) drug-resistant E. coli in four bird species in a common environment. Our results indicated that gulls, pigeons, and penguins carried drug-resistant E. coli strains, and analysis of mobile genetic elements associated with resistance genes indicated interspecies resistance transfer. Terns, representing a bird species that forages on natural food sources at sea and distant from humans, did not test positive for drug-resistant E. coli. This study demonstrates carriage of CIA-resistant bacteria in multiple bird species living in areas commonly inhabited by humans and provides further evidence for a leapfrog effect of resistance in wildlife, facilitated by feeding habits.

The neutrophil oxidative respiratory burst response is a key component of the innate immune system responsible for killing microbial pathogens. Since fish rely on the innate immune system for health, monitoring the respiratory burst activity may be an effective means of gauging fish health status. Here we report that the respiratory burst of Asian seabass neutrophils can be measured in whole blood by the dihydrorhodamine (DHR)-123 reduction assay and flow cytometry. Neutrophils responded to phorbol myristate acetate (PMA) in a concentration dependent manner with significant respiratory burst activity at 100–1000 nM. Other known neutrophil agonists, such as bacterial lipopolysaccharide, tumor necrosis factor, the tripeptide f-met-leu-phe and zymosan, did not induce a significant DHR reduction. Thus, the findings enable us to propose that the DHR-123 flow cytometry whole blood assay, incorporating PMA as a stimulator, would not only facilitate future studies into fish blood neutrophil research but provides a simple, rapid and reliable assay for gauging fish natural immunity status and health. Refereed/Peer-reviewed

Objectives Antimicrobial resistance (AMR) to critically important antimicrobials (CIAs) amongst Gram-negative bacteria can feasibly be transferred amongst wildlife, humans and domestic animals. This study investigated the ecology, epidemiology and origins of CIA-resistant Escherichia coli carried by Australian silver gulls (Chroicocephalus novaehollandiae), a gregarious avian wildlife species that is a common inhabitant of coastal areas with high levels of human contact. Methods Sampling locations were widely dispersed around the perimeter of the Australian continent, with sites separated by up to 3500 km. WGS was used to study the diversity and molecular characteristics of resistant isolates to ascertain their epidemiological origin. Results Investigation of 562 faecal samples revealed widespread occurrence of extended-spectrum cephalosporin-resistant (21.7%) and fluoroquinolone-resistant (23.8%) E. coli. Genome sequencing revealed that CIA-resistant E. coli isolates (n = 284) from gulls predominantly belonged to human-associated extra-intestinal pathogenic E. coli (ExPEC) clones, including ST131 (17%), ST10 (8%), ST1193 (6%), ST69 (5%) and ST38 (4%). Genomic analysis revealed that gulls carry pandemic ExPEC-ST131 clades (O25:H4 H30-R and H30-Rx) and globally emerging fluoroquinolone-resistant ST1193 identified among humans worldwide. Comparative analysis revealed that ST131 and ST1193 isolates from gulls overlapped extensively with human clinical isolates from Australia and overseas. The present study also detected single isolates of carbapenem-resistant E. coli (ST410-blaOXA-48) and colistin-resistant E. coli (ST345-mcr-1). Conclusions The carriage of diverse CIA-resistant E. coli clones that strongly resemble pathogenic clones from humans suggests that gulls can act as ecological sponges indiscriminately accumulating and disseminating CIA-resistant bacteria over vast distances.

Naturally, fermented milk has become an essential commodity in rural areas in some developing countries, especially in Africa and Asia. A variety of local products appear depending on local knowledge, including the type of milk, containers, and techniques. Although the microbial composition of each product varies, lactic acid bacteria commonly dominate the range of naturally fermented milk products. Research into functional benefits for human health about the role of their microflora is rapidly expanding. The role of lactic acid bacteria as probiotics for either prevention or treatment of human diseases has been a driving force in the exploration of new potential probiotics from naturally fermented milk. Inflammatory intestinal diseases are one of the digestive problems caused by dysbiosis. Therefore, the contribution of probiotics to improve the balance and diversity of intestinal microbiota has become a main concern. The main focus of this review was to summarize a variety of naturally fermented milk products by highlighting the production process and indigenous microflora involved. The determination of probiotics that are highly involved in the fermentation of milk may have health benefits for treating inflammatory intestinal diseases, especially inflammatory bowel disease and intestinal mucositis Refereed/Peer-reviewed

Antimicrobial use in animals and the potential development of antimicrobial resistance is a global concern. So, non-antimicrobial techniques for animal disease control are needed. This study aimed to determine whether neonatal ceftiofur (CF) treatment affects piglet faecal microbiomes and whether faecal microbiome transplantation (FMT) can correct it. Two focal piglets per sow were assigned to treatments as follows: cffresh (n = 6) received CF (3 mg/kg intramuscular) at 7 d and fresh FMT at 13 d, cffrozen (n = 7) received CF at 7 d and frozen FMT at 13 d, CF (n = 8) received CF at 7 d and no FMT, and no CF (n = 5) received no CF or FMT. DNA was extracted from faecal samples collected on days 7, 13, and 18 for 16S rRNA amplicon analysis. All faecal blends used for the FMT consisted of pooled donor pig faeces at 1:2 ratio with saline, delivered orally at 3 mL/kg. Alpha and beta diversity metrics increased with age (p &lt, 0.05). However, no effect of antibiotic or FMT treatment was evident in 13 and 18 d old piglets (p &gt, 0.05). Although no effect of treatment was observed, information regarding microbial membership during lactation was gained.

Background Antibiotic misuse in food-producing animals is potentially associated with human acquisition of multidrug-resistant (MDR; resistance to ≥ 3 drug classes) bacteria via the food chain. We aimed to determine if MDR Gram-negative (GNB) organisms are present in fresh Australian chicken and pork products. Methods We sampled raw, chicken drumsticks (CD) and pork ribs (PR) from 30 local supermarkets/butchers across Melbourne on two occasions. Specimens were sub-cultured onto selective media for third-generation cephalosporin-resistant (3GCR) GNBs, with species identification and antibiotic susceptibility determined for all unique colonies. Isolates were assessed by PCR for SHV, TEM, CTX-M, AmpC and carbapenemase genes (encoding IMP, VIM, KPC, OXA-48, NDM). Results From 120 specimens (60 CD, 60 PR), 112 (93%) grew a 3GCR-GNB (n = 164 isolates; 86 CD, 78 PR); common species were Acinetobacter baumannii (37%), Pseudomonas aeruginosa (13%) and Serratia fonticola (12%), but only one E. coli isolate. Fifty-nine (36%) had evidence of 3GCR alone, 93/163 (57%) displayed 3GCR plus resistance to one additional antibiotic class, and 9/163 (6%) were 3GCR plus resistance to two additional classes. Of 158 DNA specimens, all were negative for ESBL/carbapenemase genes, except 23 (15%) which were positive for AmpC, with 22/23 considered to be inherently chromosomal, but the sole E. coli isolate contained a plasmid-mediated CMY-2 AmpC. Conclusions We found low rates of MDR-GNBs in Australian chicken and pork meat, but potential 3GCR-GNBs are common (93% specimens). Testing programs that only assess for E. coli are likely to severely underestimate the diversity of 3GCR organisms in fresh meat.

Bacterial contamination of biomedical devices is an ongoing problem. One method to alleviate such contamination is the introduction of surface compounds onto devices which can kill bacteria on contact. Polymers containing quaternary ammonium groups are known for their antimicrobial properties. Here we report a substrate-independent two-step method for the immobilisation of quaternary ammonium groups onto any type of surface. To achieve this glycidlytrimethylammonium chloride was covalently bound to plasma polymerised allylmine interlayer. Changes in the membrane permeability of Escherichia coliwere observed by BacLight LIVE\DEAD staining. 30% of E. coli grown on the treated surfaces showed high levels of membrane permeability within 4 hours. Importantly, there was no observable cytotoxic effect on human dermal fibroblasts.

Simple Summary Piglet preweaning mortality is a major economic loss and welfare concern for the global pork industry, with the industry average sitting at approximately 15%. As such, novel methods for reducing this mortality are needed. Since research into the intestinal microbiota has provided advances in human health, in particular the impact of early life factors, it was the logical next step to synthesise the existing literature to determine the potential relevance to the pig industry. It is evident from the literature that this area of research provides promising results. However, a large gap within the literature currently exists within the lactation period in pigs. Since optimal development within early life is proving to be critical for human infants, it is crucial that further research is invested into understanding the impact of early life events on a piglet’s microbiome. It is hoped that this review will enable access to critical information for those interested in the microbiome and its potential for improving herd health on the farm. Abstract The intestinal microbiota has received a lot of attention in recent times due to its essential role in the immune system development and function. Recent work in humans has demonstrated that the first year of life is the most critical time period for microbiome development with perturbations during this time being proven to have long term health consequences. In this review, we describe the literature surrounding early life events in humans and mice that contribute to intestinal microbiota development and function, and compare this to piglets predominantly during their lactation period, which focuses on the impact lactation management practices may have on the intestinal microbiota. Although extensive research has been conducted in this area in humans and mice, little research exists in pigs during perceivably the most critical time period of development, which is the lactation period. The research reviewed outlines the importance of appropriate intestinal microbiota development. However, further research is needed in order to understand the full extent routine farm practices have on a piglet’s intestinal microbiota.

Bacteriophage therapy has demonstrated promising results towards the control of bacterial infections within the aquaculture industry as an alternative therapy to antibiotics. This current research describes the efficacy of bacteriophage therapy in controlling vibriosis within abalone (Haliotis laevigata). Two bacteriophages were isolated and used in in vitro assays to determine the effect of each specific phage on the growth of specific Vibrio harveyi isolates. To demonstrate efficacy, an in vivo bioassay was performed using abalone (H. laevigata) at a water temperature of 24 °C. Characterisation of the two isolated phages revealed they were from the family, Siphoviridae. The phages had different antimicrobial abilities towards different Vibrio harveyi isolates in the in vitro assays and the bioassay demonstrated improved survival of abalone treated with bacteriophage. The results of the bioassay showed that the negative control and phage control were statistically identical, with 100% survival, but they were different from the positive bacterial control, with a 0% survival. The bacteria + phage treated group showed increased accumulative survival of 70% compared to the positive control. This is the first study to demonstrate the efficacy of bacteriophage therapy treatment for abalone. The study demonstrates that if abalones are treated with bacteriophage shortly after Vibrio harveyi infection, the accumulative survival could be significantly increased. Refereed/Peer-reviewed

Resistance to antimicrobials in enterococci from poultry has been found throughout the world and is generally recognized as associated with antimicrobial use. This study was conducted to evaluate the phenotypic and genotypic profile of enterococcal isolates of intensive (indoor) and free range chickens from 2008/09 and 2000 in order to determine the patterns of antimicrobial resistance associated with different management systems. The minimum inhibitory concentrations in faecal enterococci isolates were determined by agar dilution. Resistance to bacitracin, ceftiofur, erythromycin, lincomycin, tylosin and tetracycline was more common among meat chickens (free range and intensive) than free range egg layers (PB

Antibiotic use in poultry production is a risk factor for promoting the emergence of resistant Escherichia coli. To ascertain differences in different classes of chickens, the resistance profile, some virulence genes and phylogenetic grouping on 251 E. coli isolates from intensive meat (free range and indoor commercial) and free range egg layer chickens collected between December 2008 and June 2009 in South Australia were performed. Among the 251 strains, 102 (40.6%) and 67 (26.7%) were found to be resistant to tetracycline and ampicillin respectively. Resistance was also observed to trimethoprim-sulfamethoxazole (12.4%), streptomycin (10.8%), spectinomycin (9.6%), neomycin (6.0%) and florfenicol (2.0%) but no resistance was found to ceftiofur, ciprofloxacin or gentamicin. Amplification of DNA of the isolates by polymerase chain reaction revealed the presence of genes that code for resistant determinants: tetracycline (tet(A), tet(B) and tet(C)), ampicillin (blaTEM and blaSHV), trimethoprim (dhfrV and dhfrXIII), sulphonamide (sulI and sulII), neomycin (aph(3)-Ia(aphA1)), and spectinomycin–streptinomycin (aadA2). In addition, 32.3–39.4% of the isolates were found to belong to commensal groups (A and B1) and 11.2–17.1% belonged to the virulent groups (B2 and D). Among the 251 E. coli isolates, 25 (10.0%) carried two or more virulence genes typical of Extraintestinal pathogenic E. coli (ExPEC). Furthermore, 17 of the isolates with multi-resistance were identified to be groups B2 and D. Although no significant difference was observed between isolates from free range and indoor commercial meat chickens (P< 0.05), significant differences was observed between the different classes of meat chickens (free range and indoor commercial) and egg layers (P< 0.05). While this study assessed the presence of a limited number of virulence genes, our study re emphasises the zoonotic potential of poultry E. coli isolates. Refereed/Peer-reviewed

Aims: To determine the antibacterial spectrum and cytotoxic activities of serrulatane compounds from the Australian plant Eremophila neglecta. Methods and Results: Antimicrobial activities of serrulatane compounds 8,19-dihydroxyserrulat-14-ene (1) and 8-hydroxyserrulat-14-en-19-oic acid (2) were tested against Gram-negative and Gram-positive bacteria including human and veterinary pathogens and some multidrug-resistant isolates. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the compounds were determined by broth microdilution assay. Both compounds exhibited antibacterial activity against all Gram-positive test strains. They showed antimycobacterial activity against isolates of Mycobacterium fortuitum and Mycobacterium chelonae. Of the five Gram-negative bacteria tested, only Moraxella catarrhalis showed susceptibility to the compounds. Cytotoxic activities were tested in the Vero cell line. Compound 1 showed more activity than 2 in both antibacterial and cytotoxicity assays with cytotoxicity at concentrations similar to the MBC. Conclusions: Serrulatane compounds showed significant activity against medically important bacteria, with 1 exhibiting stronger antibacterial activity. However, they also displayed toxicity to mammalian cells. Significance and Impact of the Study: Serrulatanes are of interest as novel antibacterial compounds for use in biomedical applications; this study reports data obtained with a range of bacterial strains and mammalian cells, essential for assessing the capabilities and limitations of potential applicability of these compounds.

There is limited information on antibiotic resistance determinants present in bacteria of aquaculture origin in Australia. The presence of integron and other resistance determinants was investigated in 90 Aeromonas isolates derived from nine freshwater trout farms in Victoria (Australia). Polymerase chain reaction was carried out for the detection of integrase genes Int1, Int2 and Int3, gene cassette array, integron-associated aadA, sul1 and qac1 genes, streptomycin resistance genes strA-strB, β-lactamase resistance genes bla(TEM) and bla(SHV) , and tetracycline resistance genes tetA-E and tetM. Clonal analysis was performed by pulsed-field gel electrophoresis (PFGE). Class 1 integrons were detected in 28/90 (31%) and class 2 and class 3 in none of the strains, aadA gene in 19/27 (70%) streptomycin-resistant strains, sul1 in 13/15 (86.7%) sulphonamide-resistant strains and qac1 gene in 8/28 (28.6%) integron-bearing strains. Five strains from two different farms carried gene cassettes of 1000 bp each containing the aadA2 gene and PFGE analysis revealed genetic relatedness. tetC was detected in all and tetA in 9/18 (50%) tetracycline-resistant strains. The strA-strB, bla(TEM) or bla(SHV) genes were not detected in any of the strains. Aeromonas spp. carrying integrons and other resistance genes are present in farm-raised fish and sediments even though no antibiotics were licensed for use in Australian aquaculture at the time of the study.

This study aimed to characterize antimicrobial resistance and virulence genes in multi-drug resistant enterotoxigenic Escherichia coli (ETEC) isolates (n = 117) collected from porcine post-weaning diarrhoea cases in Australia (1999-2005). Isolates were serotyped, antibiogram-phenotyped for 12 antimicrobial agents and genotyped by PCR for 30 plasmid-mediated antimicrobial resistance genes (ARGs), 22 intestinal and 38 extraintestinal E. coli virulence genes (VGs). Nine serogroups were identified, the most prevalent being O149 (46.2%), O141 (11.2%) and Ont (31.6%). None of the isolates showed resistance to ceftiofur or enrofloxacin and 9.4% were resistant to florfenicol. No corresponding extended-spectrum/AmpC β-lactamase, fluoroquinolone or floR ARGs were detected. An antimicrobial resistance index (ARI) was calculated from the combined data with a weighting for each antimicrobial agent dependent upon its significance to human health. Serogroup O141 isolates had a significantly higher ARI due to an elevated prevalence of aminoglycoside ARGs and possession of more virulence genes (VGs), including ExPEC or EHEC adhesins (bmaE, sfa/focDE, fimH, ihA) in toxin-producing strains that lacked the normally associated F4 and F18 fimbriae. Few associations between ARGs and VGs were apparent, apart from tetC, sfa/focDE and ompT which, for a sub-set of O141 isolates, suggest possible plasmid acquisition from ExPEC. The multi-drug resistant ETEC ARG/VG profiles indicate a high probability of considerable strain and plasmid diversity, reflecting various selection pressures at the individual farm level rather than emergence and lateral spread of MDR resistant/virulent clones. Refereed/Peer-reviewed

Summary Rhodococcus equi remains a significant bacterial pathogen, causing severe pyogranulomatous pneumonia in foals aged 1–3 months. There is no effective vaccine currently available for the prevention of R. equi pneumonia. DNA vaccines are known to offer specific advantages over conventional vaccines. The aim of this study was to demonstrate efficacy of our recombinant DNA vaccine candidates, namely pcDNA3-Re1 , pcDNA3-Re3 and pcDNA3-Re5 by combining a heat shock protein GroEL2 to a virulence-associated protein A (VapA) from R. equi to protect C3H/He mice against the R. equi infection. VapA was shown to be strongly recognised by sera from pneumonic foals. All vaccines elicited at least a doubling of the IgG2a/IgG1 ratio in comparison to the controls, indicating a bias to the Th1 response, which is postulated to be crucial for bacterial clearance and protective immunity against intracellular pathogens including R. equi . In addition, the immunised mice showed a significant reduction in R. equi in their lungs at 7 days after the aerosol challenge in comparison to PBS treated mice. However, examination of lung pathology 14 days after the challenge showed no gross differences in pathological changes between the unvaccinated and vaccinated animals. The lack of significant pathological changes suggests that the precise level of protection against R. equi pneumonia in the murine model of infection may not represent a true effectiveness of the potential vaccine candidates, indicating the mouse may not be the ideal non-equine model for vaccine studies and (or) the incomplete immunogenic antigen of vapA -based DNA vaccine constructs that mount an inadequate cell-mediated immune response against the R. equi infection.

We report a search for antimicrobial compounds in the Australian plant Eremophila serrulata . Bioassay directed fractionation of a diethyl ether extract prepared from the leaves of E. serrulata led to the isolation of two compounds, an ο -naphthoquinone, 9-methyl-3-(4-methyl-3-pentenyl)-2,3-dihydronaphtho[1,8- bc ]pyran-7,8-dione ( 2 ), and a serrulatane diterpenoid, 20-acetoxy-8-hydroxyserrulat-14-en-19-oic acid ( 3 ). Two other known serrulatane-type diterpenoids, 8,20-dihydroxyserrulat-14-en-19-oic acid ( 4 ) and 8,20-diacetoxyserrulat-14-en-19-oic acid ( 5 ) were also isolated. None of these compounds had previously been tested for antimicrobial activity. Compounds 2 – 5 showed antimicrobial activity against Staphylococcus aureus (ATCC 29213) with minimum inhibitory concentrations (MICs) ranging from 15.6 to 250 μg/mL. Compound 2 was the most active with an MIC of 15.6 μg/mL and a minimum bactericidal concentration (MBC) of 125 μg/mL. This compound also showed antimicrobial activity against other Gram-positive bacteria including Streptococcus pyogenes , and Streptococcus pneumoniae . No activity was observed for this compound against all Gram-negative bacteria tested.

Aims: To determine the genetic determinants responsible for tetracycline resistance in oxytetracycline resistant bacteria from aquaculture sources in Australia. Methods and Results: Twenty of 104 (19%) isolates tested were resistant to oxytetracycline (MIC ≥ 16 μg ml−1). Using polymerase chain reaction (PCR) amplification, one or more tet genes were detected in 15/20 (75%) isolates tested, but none were found in 5/20 (25%). tetM (50%) was the most common determinant, followed by tetE (45%), tetA (35%) and tetD (15%). Five of 12 oxytetracycline resistant isolates studied were able to transfer their R-plasmid to Escherichia coli recipients of chicken, pig and human origin. tetA, tetD and tetM were found to be transferred while tetE was not transferred. Southern hybridization and PCR were used to confirm transfer of determinants. Conclusions: Bacterial isolates from aquaculture sources in Australia harbour a variety of tetracycline resistance genes, which can be transferred to other bacteria of different origin. Significance and Impact of the Study: Bacteria from aquaculture sources in Australia contribute to the resistance gene pool reservoir. The in vitro transfer of tetracycline R-plasmid from aquatic bacteria to E. coli isolates from various sources is an indication of the potential public health risk associated with these resistance determinants.

Summary A total of 227 field samples from naturally exposed foals aged between 3 weeks and 6 months were used in an evaluation of a peptide-based enzyme-linked immunosorbent assay (ELISA) for diagnosis of Rhodococcus equi infection. A biotinylated peptide derived from the virulence-associated protein A (VapA) of R. equi, a horse pathogen, was synthesized and designated as PN11-14. The peptide corresponds to the N-terminal B-cell epitope TSLNLQKDEPNGRASDTAGQ of the VapA protein. Based upon a serum immunoglobulin (Ig)G titre of 512 as a positive cut-off value for the R. equi infection, the ELISA provided the overall sensitivity of 47.62%, specificity of 69.67% and an accuracy of 59.47% with a positive predictive value of 57.47% for true R. equi pneumonia. The assay was improved by detecting VapA-specific IgGb antibodies against N-terminal B-cell epitope of the VapA protein rather than IgG antibodies. The VapA-IgGb ELISA showed the overall sensitivity of 70.47%, specificity of 72.13% and accuracy of 71.36% with a positive predictive value of 68.52%. Diagnosis of R. equi disease in 6-week-old foals showed that the VapA-IgGb ELISA provided an increasing trend (P = 0.0572) in sensitivity of 82.4% in comparison with the VapA-IgG ELISA which showed the sensitivity of 58.8%. However, differences in specificity of both tests were statistically insignificant (P = 0.357) as analysed by the McNemar test. These results indicated that detection of VapA-specific IgGb antibodies may be a better predictor of R. equi disease in foals.

Methicillin-resistant staphylococci (MRS) pose a challenge to clinicians and health administrators in human medicine, but MRS infections in cats and dogs are not perceived as a problem in veterinary medicine. Ten methicillin-resistant staphylococcal isolates obtained from healthy and diseased cats and dogs were subjected to partial DNA sequencing of the mecA gene. Sequence analysis shows that MRS isolates from both healthy and diseased cats and dogs can harbor the mecA gene. The mecA genes of animal isolates were identical to that found in human MRS strains, and therefore the possibility of zoonotic transfer must be considered.

1. SUMMARY Dogs and cats have become an integral part of modern society in the developed world and as such attention is given to their care and welfare. At some stage of their lives many cats and dogs suffer from skin and other superficial staphylococcal infections such as pyoderma and otitis externa and are therefore treated with antibiotics. This practice has led to the emergence of resistant staphylococci in these animals. Antimicrobial susceptibility studies in companion animals have revealed that staphylococci isolated from cats and dogs exhibit similar resistance patterns to human staphylococci and that resistance development is influenced by the frequency of use of certain antibiotics. This review examines the antibiotic resistance patterns of the most frequently isolated staphylococci from cats and dogs and the mechanisms underlying resistance. The possible transfer of methicillin-resistant staphylococci from cats and dogs to humans has been identified as a potential public health issue. Typing tools used for epidemiological differentiation of pathogenic and nonpathogenic staphylococci and for species identification studies may help to elucidate the importance or otherwise of this problem.

The aim of this study was to evaluate the usefulness of the previously identified B-cell epitope TSLNLQKDEPNGRASDTAGQ of the VapA protein of Rhodococcus equi and its association with R. equi pneumonia. A modified peptide designated PN11-14 corresponding to the epitope was recognized by all sera from experimentally infected foals with virulent R. equi ATCC103+ containing the virulence plasmid but not by its plasmid-cured derivative ATCC103- strain. Marked levels of VapA-specific immunoglobulin (Ig)G were detected in all sera from the ATCC103+ infected foals at 2 weeks after the infection. One control animal had high titres as determined by the peptide enzyme-linked immunosorbent assay (ELISA), indicating the ELISA may not absolutely differentiate between foals with R. equi pneumonia and healthy exposed foals in farms where the prevalence of disease is high. However, numbers of animals used were small. Further evaluation of the peptide ELISA with field samples is necessary to determine whether the assay is diagnostically useful. This study showed that levels of passive transfer of maternal IgG antibodies to the epitope in newborn foals could be measured. Interestingly, the maternally derived antibodies were found to significantly (P

Medical device associated infections are a persistent medical problem which has not found a comprehensive solution yet. Over the last decades, there have been intense research efforts toward developing antibacterial coatings that could potentially improve medical outcomes. Silver nanoparticles have attracted a great deal of attention as a potent alternative to conventional antibiotics. Herein, we present a biologically inspired approach to synthesize phospholipid encapsulated silver nanoparticles and their surface immobilization to a functional plasma polymer inter layer to generate antibacterial coatings. The antibacterial efficacy of the coatings was evaluated against three medically relevant pathogens including the Gram-positive Staphylococcus aureus and Staphylococcus epidermidis, and the Gram-negative Pseudomonas aeruginosa. The innate immune response to the coatings was assessed in vitro using primary bone marrow derived macrophages (BMDM). Any potential cytotoxicity was studied with primary human dermal fibroblasts (HDFs). Overall, the coatings had excellent inhibition of bacterial growth. We also observed reduced expression of pro-inflammatory cytokines from BMDM which suggests a reduced inflammatory response. The combined properties of coatings developed in this study may make them a good candidate for application on medical devices such as catheters and wound dressings. Refereed/Peer-reviewed

Background In recent decades, bacterial antibiotic resistance (especially in enterococci) has become a significant problem for human and veterinary medicine. One of the most important antibiotic resistances in enterococci, vancomycin resistance, is encoded by van gene family. Objectives The aim of this study was to investigate antibiotic resistance to vancomycin in enterococci and the genes responsible for this resistance. Materials and Methods Two-hundred and thirty enterococcal isolates from pigs (207 isolates), chickens (15 isolates) and humans (eight isolates) were phenotypically and genotypically tested for resistance to vancomycin by minimum inhibitory concentration (MIC) and polymerase chain reaction (PCR). The van genes were confirmed by gene sequencing. Results Of the total isolates, 19% were phenotypically resistant to vancomycin, while nearly 15% contained either vanC1 or vanC2 gene. One resistant E. casseliflavus isolate with pig origin (MIC > 8 μg/mL) contained both vanC1 and vanC2 genes. Furthermore, one vanC1 was found in a sensitive E. faecalis isolate of pig origin (MIC ≤ 4 μg/mL) and one vanC2 in a resistant E. faecium isolate of chicken origin (MIC > 32 μg/mL). These genes were not accompanied by other van genes. Other detected genes were vanA in 11 E. faecium isolates of chicken origin (MIC > 32 μg/mL). No vanB genes were found. Gene sequencing results showed 100% identity with GenBank reference genes. Conclusions The current report is the first report on the detection of vanC1 and vanC2 genes in one enterococcal species with pig origin. This report is important as it proves the horizontal transfer of various vanC genes to one species possibly due to the compatibility class of plasmids. Furthermore, detection of vanC genes in E. faecalis and E. faecium isolates is important as it suggests that resistance to vancomycin in non-motile enterococci can be encoded by several mechanisms.

Infections associated with medical devices are a substantial healthcare problem. Consequently, there has been increasing research and technological efforts directed toward the development of coatings that are capable of preventing bacterial colonization of the device surface. Herein, we report on novel hybrid silver loaded poly(L-lactic acid) nanoparticles (PLLA-AgNPs) with narrowly distributed sizes (17 ± 3 nm) prepared using a combination of solvent evaporation and mini-emulsion technology. These particles were then immobilized onto solid surfaces premodified with a thin layer of allylamine plasma polymer (AApp). The antibacterial efficacy of the PLLA-AgNPs nanoparticles was studied in vitro against both gram-positive (Staphylococcus epidermidis) and gram-negative (Escherichia coli) bacteria. The minimal inhibitory concentration values against Staphylococcus epidermidis and Escherichia coli were 0.610 and 1.156 μg centerdot mL⁻¹, respectively. The capacity of the prepared coatings to prevent bacterial surface colonization was assessed in the presence of Staphylococcus epidermidis, which is a strong biofilm former that causes substantial problems with medical device associated infections. The level of inhibition of bacterial growth was 98%. The substrate independent nature and the high antibacterial efficacy of coatings presented in this study may offer new alternatives for antibacterial coatings for medical devices. Refereed/Peer-reviewed

Infections arising from bacterial adhesion and colonization on medical device surfaces are a significant healthcare problem. Silver based antibacterial coatings have attracted a great deal of attention as a potential solution. This paper reports on the development of a silver nanoparticles based antibacterial surface that can be applied to any type of material surface. The silver nanoparticles were surface engineered with a monolayer of 2-mercaptosuccinic acid, which facilitates the immobilization of the nanoparticles to the solid surface, and also reduces the rate of oxidation of the nanoparticles, extending the lifetime of the coatings. The coatings had excellent antibacterial efficacy against three clinically significant pathogenic bacteria i.e. Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa. Studies with primary human fibroblast cells showed that the coatings had no cytotoxicity in vitro. Innate immune studies in cultures of primary macrophages demonstrated that the coatings do not significantly alter the level of expression of pro-inflammatory cytokines or the adhesion and viability of these cells. Collectively, these coatings have an optimal combination of properties that make them attractive for deposition on medical device surfaces such as wound dressings, catheters and implants. Refereed/Peer-reviewed

Six hundred and sixty one samples - primarily fresh chicken faeces - were processed to isolate wild type Campylobacter jejuni bacteriophages, via overlay agar methods using C. jejuni NCTC 12662. The aims of this study were to isolate and purify bacteriophages and then test for their ability to lyse field strains of C. jejuni in vitro. Of all samples processed, 130 were positive for bacteriophages. A distinct difference was observed between samples from different poultry enterprises. No bacteriophages could be isolated from indoor broilers. The majority of bacteriophages were isolated from free range poultry - both broilers and egg layers. Bacteriophages were purified and then selected for characterization based on their ability to produce clear lysis on plaque assay, as opposed to turbid plaques. Two hundred and forty one C. jejuni field isolates were tested for sensitivity to the bacteriophages. Lysis was graded subjectively and any minimal lysis was excluded. Using this system, 59.0% of the C. jejuni isolates showed significant sensitivity to at least one bacteriophage. The sensitivity to individual bacteriophages ranged from 10.0% to 32.5% of the C. jejuni isolates. Five bacteriophages were examined by electron microscopy and determined to belong to the Myoviridae family. The physical size, predicted genetic composition and genome size of the bacteriophages correlated well with other reported Campylobacter bacteriophages. The reasons for the observed difference between indoor broilers and free range poultry is unknown, but are postulated to be due to differences in the Campylobacter population in birds under different rearing conditions. Refereed/Peer-reviewed

Aims To evaluate the phenotypic and genotypic profiles of Campylobacter spp. from poultry faecal samples from free range or intensively raised meat chickens and free range egg layers. In addition, a case-comparison study of antibiotic resistance genes from different groups of poultry and some pig strains previously collected was carried out. Methods Resistance to different antibiotics was assessed using the agar dilution method. In addition, all the strains were tested for ampicillin (blaOXA-61), erythromycin (aph-3-1), tetracycline tet(O), streptomycin (aadE), and the energy-dependent multi-drug efflux pump (cmeB) resistance genes using multiplex polymerase chain reaction. Results The evaluation of phenotypic resistance revealed all of the strains from poultry were sensitive to ciprofloxacin, gentamicin, erythromycin or tylosin. But, widespread resistance to lincomycin (51–100%), extensive resistance to ampicillin (33·3–60·2%) and less resistance to tetracycline (5·6–40·7%) were observed in the different groups of chickens. Antibiotic resistance genes blaOXA-61, cmeB and tet(O) were found in 82·6–92·7%, 80·3–89% and 22·3–30·9% Camp. coli isolates from pigs, whilst 59–65·4% and 19·2–40·7% Camp. jejuni from chickens were found to encode blaOXA-61 and tet(O), respectively. Conclusion No significant difference between isolates from free range egg layers and meat chickens (P

Up to 10 years ago Yersinia enterocolitica was regarded as an emerging pathogen and a significant cause of gastroenteritis. It has been of particular concern in northern Europe and Scandinavia, parts of North America, Japan, and New Zealand. However, in many parts of the world it is now of declining significance as a foodborne pathogen in comparison with salmonellosis and campylobacter infections. In the United States the prevalence of infection has declined from 1 per 100. 000 in 1996 to 0.36 per 100. 000 population in 2008. However, in Europe the prevalence is greater than 2 per 100. 000 population. Yersinia enterocolitica was first recognized as a pathogen in the 1960s and has been acknowledged as a cause of gastroenteritis since the 1980s. Infections with Y. enterocolitica are usually sporadic, but a number of outbreaks were reported in the past years. Many foods, including milk and dairy products, have been incriminated as the source of the organism, but it is now generally accepted that pigs, directly or indirectly, are the major source of human infections. Human infections are caused by a small number of pathogenic serotypes that carry a virulence plasmid encoding a number of virulence factors. Culture-dependent methods for the isolation of Y. enterocolitica from clinical, food, or environmental samples have limitations, and there is an increasing trend to the use of molecular methods to detect the organism and differentiate it from environmental relatives. Raw and pasteurized milk and dairy products will support the growth of pathogenic strains of Y. enterocolitica and it grows readily at refrigeration temperatures. Hence care must be taken to avoid contamination of milk and dairy products during and after production

Antibiotic resistance in animal isolates of enterococci is of public health concern because of the risk of transfer of antibiotic resistance isolates or resistance determinants to consumers via the food chain. In this study, phenotypic and genotypic resistance in 192 pig isolates of enterococci to ampicillin, avilamycin, avoparcin, bacitracin, flavophospholipol, gentamicin, narasin, tetracycline, tiamulin, tylosin, vancomycin, virginiamycin, copper and zinc were investigated by susceptibility test and molecular methods. Resistance rates varied between the species but all isolates were susceptible to ampicillin, avilamycin, avoparcin, gentamicin and narasin but resistant to tetracycline and tylosin and intermediately resistant to copper. Only Enterococcus gallinarum and Enterococcus casseliflavus were resistant to vancomycin and virginiamycin resistance was present in less than half the Enterococcus faecium isolates. Zinc resistance was largely confined to Enterococcus faecalis but bacitracin resistance was uncommon in E. faecalis in comparison with the other species. Tiamulin resistance was common in all species except E. casseliflavus. Resistance to flavophospholipol was detected in most E. faecium isolates and in a high proportion of E. gallinarum, E. casseliflavus and E. hirae/durans but was only found in one isolate of E. faecalis. No tetO, rplC, rplD, vanA, vanB, vatA and vatD genes were found. The presence of ermB, tetL, tetM, tcrB, aac6-aph2, tetK, tetS, vanC1, vanC2, lsaA, lsaB and vatE varied between the species and largely corresponded to the susceptibility phenotype. The findings show that resistance to antibiotics of high clinical significance for nosocomial Enterococcus infections is absent, whereas antimicrobial resistance was detected for some other antibiotics including bacitracin, flavophospholipol, tetracycline, tiamulin, tylosin and virginiamycin. Refereed/Peer-reviewed

Objective To describe how various antimicrobials are used in commercial pig herds in Australia and for what disease conditions. Procedure Managers of large pig herds (> 200 sows) across Australia and their veterinarians participated in an internet-based survey in 2006. Questions were asked about herd management, the occurrence of bacterial diseases and the type and frequency of antimicrobial use. An antimicrobial usage index for each herd was derived as a summary of the risk of selection for antimicrobial resistance. Relationships between responses were explored with univariate and multivariate analysis. Results Responses were received for 197 herds estimated to represent at least 51% of all large pig herds in Australia. Most piggeries relied on drugs of low importance in human medicine (e.g. tetracyclines, penicillins and sulfonamides). For the two drugs of high importance in human medicine that can be legally prescribed to pigs in Australia, ceftiofur use was reported in 25% of herds and virginiamycin in none. Infections attributed to Lawsonia, Mycoplasma and Escherichia coli motivated the most use of antimicrobials. No useful association was found between management factors and the antimicrobial use index. Conclusion Most antimicrobial use in the Australian pig industry is based on drugs of low importance to public health. Enhanced control of E. coli infections without reliance on antimicrobials would further reduce the risk of selecting for antimicrobial resistance relevant to public health. The amount of variation in the usage index between herds suggests that antimicrobial use should be constantly reviewed on a herd by herd basis.

Plant species of the genus Eremophila (Myoporaceae) are native to Australia and are known to produce a diverse range of unusual secondary compounds. The purpose of this research was to examine the antimicrobial activity of 72 Eremophila species most of which had not been the subject of any previous pharmacological testing. Organic extracts of Eremophila species were screened for antimicrobial activity against Gram-positive and Gram-negative bacteria and yeasts of medical importance. Extracts of a number of Eremophila species showed selective activity against Gram-positive bacteria with MICs for the most active species in the range of 16 to 62 μg/ml for Streptococcus species, and 62 to 250 μg/ml for standard strains of Staphylococcus aureus. Extracts with the greatest activity against standard strains were tested against 68 clinical isolates of multi-resistant methicillin-resistant S. aureus (mMRSA). The majority of the clinical isolates were susceptible to concentrations below 62.5 μg/ml for the extracts of E. drummondii, E. linearis, E. serrulata, E. acrida, E. neglecta, E. virens and a new undescribed species affiliated with E. prolata. The extract of E. virens inhibited growth of all 68 clinical mMRSA isolates at the minimum tested concentration of 31 μg/ml. This study has shown for the first time that a number of different Eremophila species manifest selective antibacterial activity against Gram-positive organisms which are important causes of human disease. It shows that there are several Eremophila species possessing interesting antibacterial activity besides those that have published traditional use. These may yield novel antibacterial compounds with potential to be used in biomedical applications. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A total of 129 Pseudomonas spp. and 90 Aeromonas spp. were isolated from nine rainbow trout (Oncorhynchus mykiss) farms in Australia. All the isolates were tested for sensitivity to 15 antibiotics and the multiresistant strains were tested for sensitivity to seven heavy metals. Minimal inhibitory concentrations (MICs) were determined by the agar dilution method. In Pseudomonas spp., resistance to amoxicillin, cefalothin, ceftiofur, ticarcillin, chloramphenicol, florfenicol, streptomycin, nitrofurantoin and trimethoprim was widespread, whereas resistance to cefotaxime and oxolinic acid was less common and only single isolates were resistant to tetracycline and sulfamethoxazole; all isolates were sensitive to ciprofloxacin and gentamicin. In Aeromonas spp., resistance to amoxicillin and cefalothin was widespread, resistance to ticarcillin, tetracycline and streptomycin was common, whilst resistance to ceftiofur, florfenicol and sulfamethoxazole was less common. Single isolates were resistant to chloramphenicol, nitrofurantoin and trimethoprim, and all isolates were sensitive to cefotaxime, oxolinic acid, ciprofloxacin and gentamicin. Multiple resistance was also observed. Most isolates were tolerant to different concentrations of various heavy metals, as evidenced by their MICs ranging from 6.25 microg/mL to >3200 microg/mL. These results confirm our previous findings that bacteria resistant to antibiotics are present in fish and sediments from aquaculture in Australia. In addition, we have found resistance to heavy metals in fish and sediment isolates. Much of the antibiotic resistance detected is likely to be intrinsic, although resistance to oxytetracycline, streptomycin and sulfonamides suggests either contamination from run-off from farms or perhaps off-label use of antibiotics in a situation where no antibiotics are licensed for use in aquaculture.

Staphylococci are part of the normal microflora of humans and animals and some are potential pathogens that have become resistant to almost all known antibiotics. Despite the widespread reports of penicillin resistance in cat and dog staphylococci, the mechanism underlying penicillin resistance has not been examined. This study was aimed at investigating the molecular basis of resistance to penicillin in cat and dog staphylococcal isolates that showed phenotypic resistance to beta-lactam antibiotics. An 861 bp fragment of the structural blaZ gene which codes for beta-lactamase production in staphylococci was amplified by polymerase chain reaction (PCR) and the products were sequenced. Sequenced fragments were analysed by protein signature typing and sequences were compared to published blaZ sequences of human and bovine staphylococcal strains held in a public database. Four known protein signature types (1, 3, 5 and 6) and one new type (12) were identified in this study. When sequences were compared with published blaZ sequences, gene phylogenetic analysis revealed three major groups. The four variants of beta-lactamases types (A, B, C and D) belonged to each major group except for types A and D which were both in group II. These findings confirm that the blaZ gene is responsible for beta-lactamase production leading to subsequent resistance to beta-lactam antibiotics in feline and canine staphylococci and that the gene shows similar diversity and relatedness as found with blaZ sequences obtained from human and bovine staphylococci.

Methicillin-resistant staphylococci (MRS) isolates from healthy and diseased cats and dogs were characterized by staphylococcal cassette chromosome mec (SCCmec), multilocus sequence typing (MLST) and cassette chromosome recombinase gene (ccrAB) sequencing.PCR-directed SCCmec typing was carried out for all MRS isolates and two Staphylococcus aureus and two Staphylococcus epidermidis strains were analysed by MLST. Strains belonging to SCCmec type III and IV were sequenced for their ccrAB gene of allotypes 3 and 2, respectively.Five types of SCCmec, types I, III, IV, IV (paediatric) and V SCCmec, were found. The S. aureus strains belonged to sequence type (ST) 239 and the two S. epidermidis belonged to ST43 and ST60 respectively. High sequence conservation was observed for the ccrAB gene of allotypes 2 and 3.MRS isolates from cats and dogs demonstrate a similar diversity of SCCmec types to those found in human staphylococci and ST239-MRSA-III, a widely dispersed strain in human hospitals, was identified in diseased dogs.

Aims: To carry out a preliminary assessment of the occurrence of resistance to antimicrobials in bacteria that has been isolated from a variety of aquaculture species and environments in Australia. Method and Results: A total of 100 Gram-negative (Vibrio spp. and Aeromonas spp. predominantly) and four Gram-positive bacteria isolated from farmed fish, crustaceans and water from crab larval rearing tanks were obtained from diagnostic laboratories from different parts of Australia. All the isolates were tested for sensitivity to 19 antibiotics and Minimal Inhibitory Concentrations were determined by the agar dilution method. Plasmid DNA was isolated by the alkali lysis method. Resistance to ampicillin, amoxycillin, cephalexin and erythromycin was widespread; resistance to oxytetracycline, tetracycline, nalidixic acid and sulfonamides was common but resistance to chloramphenicol, florfenicol, ceftiofur, cephalothin, cefoperazone, oxolinic acid, gentamicin, kanamycin and trimethoprim was less common. All strains were susceptible to ciprofloxacin. Multiple resistance was also observed and 74·4% of resistant isolates had between one and ten plasmids with sizes ranging 2–51 kbp. Conclusions: No antibiotics are registered for use in aquaculture in Australia but these results suggest that there has been significant off-label use. Significance and impact of study: Transfer of antibiotic resistant bacteria to humans via the food chain is a significant health concern. In comparison with studies on terrestrial food producing animals, there are fewer studies on antibiotic resistance in bacteria from aquaculture enterprises and this study provides further support to the view that there is the risk of transfer of resistant bacteria to humans from consumption of aquaculture products. From the Australian perspective, although there are no products registered for use in aquaculture, antimicrobial resistance is present in isolates from aquaculture and aquaculture environments.

Antibiotic resistance, particularly with the fluoroquinolones and macrolide antibiotics, has now emerged globally with thermophilic campylobacters, including Campylobacter jejuni and C. coli, giving rise to concerns about how these organisms have acquired such resistance characteristics, as well as consequences for human and animal treatment. This review examines (i) the clinical epidemiology of antibiotic resistance in human and animal thermophilic campylobacters, (ii) an update on resistance rates globally, (iii) surveillance of antimicrobial resistance in campylobacters originating from animals, particularly poultry, (iv) the role of the environment in the acquisition and transmission of antibiotic-resistant campylobacters, as well as (v) issues of biocide resistance in campylobacters.

Linear B-cell epitopes of the Rhodococcus equi virulence-associated protein (VapA) were mapped using a synthetic peptide bank in this study. The peptides were screened in an enzyme-linked immunosorbent assay (ELISA) with a total of 70 sera from foals with current R. equi disease (51 sera), as well as from foals that had either recovered from R. equi infection 10 months previously (3 sera) or that had no known history of R. equi disease (16 sera). An epitope with the sequence NLQKDEPNGRA was identified and was universally recognized by all 51 sera from foals with R. equi disease and was not recognized by any of the other sera. There was poor reactivity between all sera and peptides relating to other areas of the VapA protein. It is proposed that an ELISA based upon a defined peptide epitope may be used in an improved serological diagnostic test for R. equi infection in foals.

Antibiotic resistance in bacteria that cause disease in man is an issue of major concern. Although misuse of antibiotics in human medicine is the principal cause of the problem, antibiotic-resistant bacteria originating in animals are contributory factors, with some types of resistance in some species of bacteria. Antibiotics are added to animal feeds to treat and prevent infections and to improve growth and production. Until recently, the major concerns about incorporation of antibiotics in animal feeds related to antibiotic residues in products from treated animals. Although, in 1969, the Swann (1969) report drew attention to the potential for antibiotic-resistant bacteria to spread from treated animals via the food chain, there was little response until the detection of vancomycin-resistant enterococci in animals fed a related glycopeptide, avoparcin. Subsequently, attention started to focus on the issue and other examples of transfer of resistant bacteria through the food chain, such as enterococci resistant to quinupristin–dalfopristin or to everninomicin, fluoroquinolone-resistant campylobacters and multiresistantEscherichia coli, and salmonella such asSalmonella typhimuriumDT104. Reviews and committees in many countries have highlighted the need for better control of licensing of antibiotics, and codes for prudent use of antibiotics by veterinary practitioners and farmers. The continued use of antibiotic growth promoters has been questioned and there is a need to ensure that antibiotics important in human medicine are not used therapeutically or prophylactically in animals.

The suitability of PCR (based on the amplification of the 16S rRNA gene) for use as a diagnostic test for the detection of Campylobacter spp. in human faecal specimens was assessed. A total of 493 faecal specimens from patients with symptoms of enteritis were tested for the presence of campylobacters using PCR. Results were compared with those obtained from the analyses of the same specimens by culture techniques, using chi 2 square with Fisher's exact test. PCR was found to detect significantly more positive specimens than culture (chi 2 = 200.086; P0.0001). The sensitivity and specificity of PCR when compared with the culture technique were found to be 91 and 97%, respectively. It is proposed that the PCR is a reliable and sensitive method which may be used as a routine diagnostic technique for the detection of campylobacters in clinical specimens.

Humans and animals intimately sharing the same environment will inevitably be exposed to each other's microbiota. When one of those organisms is a drug-resistant pathogen then logistics of disease prevention are raised to a new level of complexity. For this reason the study of methicillin resistant Staphylococcus aureus (MRSA) in man and animals is now a priority. Recent research has demonstrated the ease with which MRSA crosses species barriers and the grave potential for MRSA to cause serious disease in animals and man has been well established. However, a key feature of MRSA (as compared zoonotic, resistant Salmonella spp.) is that companion and performance animals appear to have pivotal roles in the ecology of spread of certain genotypes found in humans. In this article we summarise the major developments in animal-human MRSA with an emphasis on the most recent Australian data incriminating involvement of companion and performance animals in the ecology of spread. Refereed/Peer-reviewed