Prevalence Of Antibiotic-resistant Bacteria Research Articles

Role prediction of Gram-negative species in the resistome of raw cow's milk

Extended use of antibiotics in dairy farming for therapeutic and prophylactic reasons, but also the higher prevalence of antibiotic resistant bacteria (ARB) in the farm environment raised the concern of consuming raw cow's milk and its derived products. The aim of this study was to predict by shotgun metagenomic analyses the presence of antibiotic resistance genes (ARGs) mainly correlated with Gram-negative bacteria in antibiotic residue free raw cow's milk derived exclusively from healthy animal from South Tyrol (Northern Italy), chosen as a model system. Assessment of shotgun metagenomic data of reconstructed scaffolds, revealed the existence of Pseudomonas spp. as the most abundant Gram-negative species in the raw cow's milk samples bearing ARGs. Besides, ARGs also linked to lactic acid bacteria such as Lactococcus sp. and Lactobacillus sp. ARGs correlated to microbiome found in milk samples conferred resistance towards aminoglycoside-streptothricin, beta-lactamase, macrolide, tetracycline, carbapenem, cephalosporin, penam, peptide, penem, fluoroquinolone, chloramphenicol and elfamycin antibiotics. Further bioinformatic processing included de-novo reassembly of all metagenomic sequences from all milk samples in one, to reconstruct metagenome assembled genomes (MAGs), which were further used to investigate mobile genetic elements (MGE). Analyses of the reconstructed MAGs showed that, MAG 9 (Pseudomonas sp1.) contained the oriT gene (origin of transfer gene) needed for transferring virulent factors. Although the presence of Pseudomonas is common in raw cow's milk, pasteurization treatment reduces their survivability. Nevertheless, attention should be paid on Pseudomonas spp. due to their intrinsic resistance to antibiotics and their capability of transferring virulent factors to other bacteria.

Identification of Natural Mutations Responsible for Altered Infection Phenotypes of Salmonella enterica Clinical Isolates by Using Cell Line Infection Screens.

The initial steps of Salmonella pathogenesis involve adhesion to and invasion into host epithelial cells. While well-studied for Salmonella enterica serovar Typhimurium, the factors contributing to this process in other, host-adapted serovars remains unexplored. Here, we screened clinical isolates of serovars Gallinarum, Dublin, Choleraesuis, Typhimurium, and Enteritidis for adhesion to and invasion into intestinal epithelial cell lines of human, porcine, and chicken origins. Thirty isolates with altered infectivity were used for genomic analyses, and 14 genes and novel mutations associated with high or low infectivity were identified. The functions of candidate genes included virulence gene expression regulation and cell wall or membrane synthesis and components. The role of several of these genes in Salmonella adhesion to and invasion into cells has not previously been investigated. The genes dksA (encoding a stringent response regulator) and sanA (encoding a vancomycin high-temperature exclusion protein) were selected for further analyses, and we confirmed their roles in adhesion to and invasion into host cells. Furthermore, transcriptomic analyses were performed for S Enteritidis and S Typhimurium, with two highly infective and two marginally infective isolates for each serovar. Expression profiles for the isolates with altered infection phenotypes revealed the importance of type 3 secretion system expression levels in the determination of an isolate's infection phenotype. Taken together, these data indicate a new role in cell host infection for genes or gene variants previously not associated with adhesion to and invasion into the epithelial cells.IMPORTANCESalmonella is a foodborne pathogen affecting over 200 million people and resulting in over 200,000 fatal cases per year. Its adhesion to and invasion into intestinal epithelial cells represent one of the first and key steps in the pathogenesis of salmonellosis. Still, around 35 to 40% of bacterial genes have no experimentally validated function, and their contribution to bacterial virulence, including adhesion and invasion, remains largely unknown. Therefore, the significance of this study is in the identification of new genes or gene allelic variants previously not associated with adhesion and invasion. It is well established that blocking adhesion and/or invasion would stop or hamper bacterial infection; therefore, the new findings from this study could be used in future developments of anti-Salmonella therapy targeting genes involved in these key processes. Such treatment could be a valuable alternative, as the prevalence of antibiotic-resistant bacteria is increasing very rapidly.

Detection of Emerging Pollutants Oxytetracycline and Paracetamol and the Potential Aquatic Ecological Risk Associated with their Presence in Surface Waters of the Arges-Vedea, Buzau-Ialomita, Dobrogea-Litoral River Basins in Romania

Pharmaceuticals are a major group of emerging pollutants frequently identified in surface waters. The occurrence of pharmaceuticals as environmental pollutants is a problem involving multiple aspects and continue to cause new and serious challenges to ecosystems and human health. For example, antibiotics exert a selective pressure on bacterial communities in aquatic environments, leading to the selection and increase in the prevalence of antibiotic-resistant bacteria, which is a major problem in the effective treatment of bacterial infections, while for analgesics, a number of adverse effects such as accumulation in tissues and behavioral changes were observed in aquatic organisms. In this paper, the detection by UHPLC-MS/MS of two widely used pharmaceuticals was performed, oxytetracycline (antibiotic) and paracetamol (analgesic) respectively, in surface water matrix from the Arges-Vedea, Buzau-Ialomita and Dobrogea-Litoral river basins in Romania. The potential aquatic ecological risk (RQ) was also estimated by the ratio between Measured Environmental Concentration (MEC) and Predicted No-Effect Concentration (PNEC).

The microbial safety of fish and fish products: Recent advances in understanding its significance, contamination sources, and control strategies.

Microorganisms play a crucial and unique role in fish and fish product safety. The presence of human pathogens and the formation of histamine caused by spoilage bacteria make the control of both pathogenic and spoilage microorganisms critical for fish product safety. To provide a comprehensive and updated overview of the involvement of microorganisms in fish and fish product safety, this paper reviewed outbreak and recall surveillance data obtained from government agencies from 1998 to 2018 and identified major safety concerns associated with both domestic and imported fish products. The review also summarized all available literature about the prevalence of major and emerging microbial safety concerns, including Salmonella spp., Listeria monocytogenes, and Aeromonas hydrophila, in different fish and fish products and the survival of these pathogens under different storage conditions. The prevalence of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs), two emerging food safety concerns, is also reviewed. Pathogenic and spoilage microorganisms as well as ARB and ARGs can be introduced into fish and fish products in both preharvest and postharvest stages. Many novel intervention strategies have been proposed and tested for the control of different microorganisms on fish and fish products. One key question that needs to be considered when developing and implementing novel control measures is how to ensure that the measures are cost and environment friendly as well as sustainable. Over the years, regulations have been established to provide guidance documents for good farming and processing practices. To be more prepared for the globalization of the food chain, harmonization of regulations is still needed.

NKL-24: A novel antimicrobial peptide derived from zebrafish NK-lysin that inhibits bacterial growth and enhances resistance against Vibrio parahaemolyticus infection in Yesso scallop, Patinopecten yessoensis

The extensive use of antibiotics in aquaculture has resulted in the prevalence of antibiotic-resistant bacteria and, consequently, new antibacterial strategies or drugs with clear modes of action are urgently needed. Antimicrobial peptides (AMPs) are currently widely considered as alternatives to antibiotics in the treatment of infections in aquatic animals. In this study, we aimed to evaluate the effects of NKL-24, a truncated peptide derived from zebrafish NK-lysin, against Yesso scallop (Patinopecten yessoensis) pathogen, Vibrio parahaemolyticus. The results showed that NKL-24 had a potent antibacterial effect against V. parahaemolyticus via a membrane active cell-killing mechanism. The in vitro study showed that sub-lethal levels of NKL-24 obviously reduced bacterial swimming ability and downregulated the transcription of the selected genes associated with V. parahaemolyticus virulence. Studies on NKL-24 biosafety in hemocytes and in Yesso scallop have shown no adverse effects from this peptide. Bacteria challenge test results demonstrated that NKL-24 significantly decreased the mortality and inhibited bacterial growth in the scallop infected with V. parahaemolyticus, while further in vivo examination revealed that NKL-24 could enhance non-specific immune parameters. Moreover, NKL-24 was capable of modulating a series of V. parahaemolyticus-responsive genes in the scallop. These results suggest the protective action of NKL-24 against V. parahaemolyticus and the potential of this peptide as a promising candidate for aquaculture applications.

Selection of antibiotic resistance by metals in a riverine bacterial community

Antibiotic resistance is a health challenge across human, animal and environmental settings. In the environment, metals may contribute to antibiotic resistance selection. This study aimed to investigate the role of copper and zinc in the selection of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in a riverine bacterial community. Using a microcosm approach, bacteria in water samples were exposed to 50 μg L−1 and 100 μg L−1 of copper and zinc, for 20 days. The prevalence of ARB was determined from colony forming units counts in media with and without antibiotics. A significant increase in the prevalence of cefotaxime-resistant (from 2.3% in control to 9.5% in Cu50 and 16.8% in Cu100) and tetracycline-resistant bacteria (from 0.03% to 0.23% in Cu100) was observed in communities exposed to copper. Zinc exposure resulted in an increase in the prevalence of cefotaxime-resistant bacteria (from 24.6% to 91.3% in Zn50 and 72.4% in Zn100) and of kanamycin-resistant bacteria (from 6.1% to 24.1% in Zn50 and 43% in Zn100). Cefotaxime- and kanamycin-resistant bacteria belonged to genera intrinsically resistant to these compounds. DGGE profiling confirmed that metal exposure altered the structure and diversity of bacterial communities. Changes in the abundance of genes usually associated with mobile genetic elements (blaCTX-M, blaTEM, tet(A) and intI1) were not detected after exposure. Results demonstrated the selection of bacteria intrinsically resistant to antibiotics imposed by copper and zinc exposure, suggesting an important role played by cross-resistance mechanisms.

Antibacterial and Anti-Inflammatory Effects of Novel Peptide Toxin from the Spider Pardosa astrigera.

The prevalence of antibiotic-resistant bacteria has become an immediate threat to public health. Antimicrobial peptides are attracting attention as a new source of antibiotics due to their ability to prevent drug-resistances with fewer side effects. Spider venom is composed of various bioactive substances with multiple functionalities such as antimicrobial and anti-inflammatory effects. Here, RNA sequencing was conducted on the venom gland of the spider Pardosa astrigera, and a potential toxin peptide with antibacterial properties was selected via homology and in silico analysis. A novel toxin, Lycotoxin-Pa4a, inhibited both gram-negative and gram-positive bacteria by disrupting the outer and bacterial cytoplasmic membrane. Moreover, the peptide downregulated the expression of pro-inflammatory mediators while upregulating the level of anti-inflammatory cytokine by inactivating mitogen-activated protein kinase signaling in a lipopolysaccharide-stimulated murine macrophage cell line. In this research, we identified a novel peptide toxin, Lycotoxin-pa4a, with antibacterial and anti-inflammatory properties, suggesting its potential for the development of a new antibiotics, as well as offering insights into the utilization of biological resources.

MULTIDRUG RESISTANT BACTERIA IN DUMPSITE SOILS WITHIN ABRAKA, DELTA STATE, NIGERIA

This study investigated the prevalence of antibiotic resistant bacteria in soils obtained from dumpsites in Abraka, Delta State. Four (4) dumpsites were assayed and composite soil samples were collected from each dumpsite. Isolates were obtained using the standard pour-plate method and pure cultures identified based on their cultural and biochemical characteristics. These were then subjected to antibiotic susceptibility test using the agar-disc diffusion method. A total of 61 isolates were obtained and identified to belong to nine (9) different genera. The isolates were Escherichia sp, Klebsiella spp, Staphylococcus sp, Bacillus spp, Pseudomonas sp, Proteus spp, Micrococcus sp, Streptococcus sp and Neisseria sp. Among the isolates obtained, Escherichia sp had the highest occurrence (26.23%) and Neisseria sp the lowest occurrence frequency of 1.63%. Pefloxacin was the least effective antibiotic as 96% and 76.67% of gram-positive and gram-negative organisms respectively, were resistant to the drug. All the isolates exhibited multidrug tolerance and a multiple antibiotic resistance (MAR) index of 0.8 was recorded for 31.15% of the isolates tested. The implication of these findings is a possible spread of persistent bacterial infections among the resident population. Proper waste management and siting of dumpsites in locations distant from residential areas will help in preventing the public health hazards associated with dumpsites.

Revealing antimicrobial resistance in stormwater with MinION

Discharge of urban stormwater containing organic matter, heavy metals and sometime human feces, to the natural aquatic reservoirs without any treatment is not only an environmental problem. It can lead to prevalence of antibiotic resistant bacteria in stormwater systems and transmission of antibiotic resistance genes to the environment. We performed antibiotic resistome identification and virus detection in stormwater samples from Stockholm, using publicly available metagenomic sequencing MinION data. A MinION platform offers low-cost, precise environmental metagenomics analysis. 37 groups of antibiotic resistant bacteria (ARB), 11 resistance types with 26 resistance mechanisms – antibiotic resistance genes (ARGs) giving tolerance to the aminoglycoside, beta-lactams, fosmidomycin, MLS, multidrug and vancomycin were identified using ARGpore pipeline. The majority of the identified bacteria species were related to the natural environment such as soil and were not dangerous to human. Alarmingly, human pathogenic bacteria carrying resistance to antibiotics currently used against them (Bordetella resistant to macrolides and multidrug resistant Propionibacterium avidum) were also found in the samples. Most abundant viruses identified belonged to Caudovirales and Herpesvirales and they were not carrying ARGs. Unlike the virome, resistome and ARB were not unique for stormwater sampling points. This results underline the need for extensive monitoring of the microbial community structure in the urban stormwater systems to assess antimicrobial resistance spread.

Antibiotic-resistant Escherichia coli and Klebsiella spp. in greywater reuse systems and pond water used for agricultural irrigation in the West Bank, Palestinian Territories

Treating and reusing greywater for agricultural irrigation is becoming increasingly prevalent in water-scarce regions such as the Middle East. However, the potential for antibiotic-resistant bacteria to be introduced into food systems or the environment via greywater reuse is a potential area of concern. It is known that off-grid treated greywater often has elevated levels of bacteria, however, little is known regarding the prevalence of antibiotic-resistant bacteria in this water source. To address this knowledge gap, samples (n = 61) of off-grid, household greywater (influent), treated greywater effluent, and irrigation pond water were collected between October 2017 and June 2018 from four farms in the West Bank, Palestinian Territories. Samples were tested for pH, turbidity, dissolved oxygen, electrical conductivity, and oxidation reduction potential. Standard membrane filtration was used to enumerate presumptive Escherichia coli, and isolates (n = 88) were purified, confirmed using 16S rRNA sequencing, and subjected to antimicrobial susceptibility testing using microbroth dilution. The majority of influent (76.5%) and effluent (70.6%) samples had detectable presumptive E. coli. Interestingly, the majority of the isolates were confirmed as Klebsiella sp. (n = 37), followed by E. coli (n = 32), and the remainder were classified as other Enterobacteriaceae (n = 19). A higher percentage of effluent isolates were fully susceptible to all tested antibiotics when compared to influent isolates (28.6% vs 18.6%). Resistance was most commonly observed against ampicillin (69.3% of all isolates), trimethoprim-sulfamethoxazole (11.4%), tetracycline (9.1%), and cefazolin (7.9%), and 7.9% of isolates were observed to be multidrug-resistant. While most water quality parameters were within Israeli and Palestinian wastewater reuse requirements, E. coli levels in effluent violated available standards. These findings suggest that, despite observed decreases in bacteria and an overall decrease in isolates expressing antibiotic resistance from influent to effluent, off-grid greywater treatment systems are still a potential source of both susceptible and antibiotic-resistant bacteria in the agricultural environment.

Distribution and prevalence of antibiotic resistant bacteria in fish farms in East Malaysia

Aims: Aquaculture has grown tremendously in Malaysia over the past decades. However, guaranteeing aquaculture sustainability is a big challenge in terms of maintaining continuous output with a safe environment. Furthermore, the cultured species should be free from antibiotic resistance bacterial and antibiotic residue. This study aimed to monitor the existence and prevalence of antibiotic resistant bacteria associated with aquaculture farms in Sarawak. Methodology and results: Samples of water, sediment and fish were collected from five aquaculture farms within Sarawak. The samples were plated on trypticase soy agar and incubated at 28 °C for 24 h. A total of 204 bacterial isolates were isolated and analysed by (GTG)5-fingerprinting to determine genetic similarity among the bacterial isolates, so that representatives could be selected from similar clonal isolates. Based on the (GTG)5 profiles, 50 representative isolates were chosen for species identification using 16S rRNA sequencing. The identified bacteria were tested against 25 antibiotics using standard disk diffusion method. The 16S rRNA analysis revealed that the isolates constitute of 14 genera of bacteria including Bacillus (38%), Exiguobacterium (16%), Enterobacter (14%), Aeromonas (6%), Acinetobacter (4%), Citrobacter (4%), Staphylococcus (4%), Achromobacter (2%), Chitinophaga (2%), Fictibacillus (2%), Plesiomonas (2%), Pseudomonas (2%), Pseudoxanthomonas (2%) and Stenotrophomonas (2%). The antibiotic resistance analysis revealed that the highest percentage of resistance was recorded against streptomycin (75.0%), followed by ampicillin (66.0%), ceftriaxone (50.0%), rifampin (43.3%), aztreonam (36.8%) and ceftazidime (31.6%). Resistance to more than two antibiotics was observed in 40.0% of isolates with an overall multiple antibiotic resistant (MAR) index ranging from 0 to 0.79. Conclusion, significant and impact of study: The variability of antibiotic resistance patterns exhibited by different bacterial species suggests a dependence on selective pressures exhibited in different geographical locations. Our results show that the occurrence of MAR bacteria in an aquaculture environment with unknown history of antibiotics usage in the aquaculture system is possible, indicating a need to continuously monitor the presence of antibiotic resistant bacteria in the aquaculture system.

Prevalence of antibiotic resistant bacteria isolated from raw chicken meat

Prevalence of antibiotic resistant bacteria isolated from raw chicken meat

Surveillance of antibiotic resistant Escherichia coli in human populations through urban wastewater in ten European countries

Antibiotic resistance surveillance data is lacking in many parts of the world, limiting effective therapy and management of resistance development. Analysis of urban wastewater, which contains bacteria from thousands of individuals, opens up possibilities to generate informative surveillance data in a standardized and resource-efficient way. Here, we evaluate the relationship between antibiotic resistance prevalence in E. coli from wastewater and clinical samples by studying countries with different resistance situations as assessed by traditional clinical surveillance. Composite, influent wastewater samples were collected over 24 h from treatment plants serving major cities in ten European countries. Using a broth screening method, resistance to six antibiotic classes was analyzed for 2507 E. coli isolates (n = 247–252 per country). Resistance prevalence in wastewater E. coli was compared to that in clinical E. coli reported by the European Antibiotic Resistance Surveillance Network. Resistance prevalence was lower in wastewater than clinical E. coli but followed similar geographic trends. Significant relationships were found for resistance to aminopenicillins (R2 = 0.72, p = 0.0019) and fluoroquinolones (R2 = 0.62, p = 0.0072), but not for aminoglycosides (R2 = 0.13, p = 0.31) and third-generation cephalosporins (R2 = 0.00, p = 0.99) where regression analyses were based on considerably fewer resistant isolates. When all four antibiotic classes were taken into account, the relationship was strong (R2 = 0.85, p < 0.0001). Carbapenem resistance was rare in both wastewater and clinical isolates. Wastewater monitoring shows promise as method for generating surveillance data reflecting the clinical prevalence of antibiotic resistant bacteria. Such data may become especially valuable in regions where clinical surveillance is currently limited.

Prevalence of Antibiotic Resistant Bacteria in Nigerian Fermented Food Condiments

Food borne diseases remain a growing public health problem gotten through the consumption of contaminated food and water. A world health organization report, 2015 estimated 600million episodes of illness due to contaminated food worldwide. Amongst all age groups, Africa bore the greatest burden of diarrhoeal diseases. Gram-negative bacteria have become a significant challenge to the control of infection as a result of acquisition of antibiotic resistant genes. This is especially of concern in Nigeria where fermented condiments are important part of daily meals and sometimes consumed without cooking. This work thus identifies Gram negative bacteria from fermented condiments and evaluates the antibiotic resistance profile of the bacterial isolates. The fermented condiments- Iru (Parkia biglobosa) (67), Ogiri-igbo (Ricinus communis) (58), Ukpaka (Pentaclethra macrophylla) (22) and Okpei (Prosopis africana) (42), were obtained from markets in Abuja, Gboko, Lokoja, Okenne, Abeokuta, Ibadan, Ijebu-Ode, Ilorin, Lagos, Ondo and Ore. Coliform and faecal coliform test was done. Isolation of the Gram-negative bacteria was done using MacConkey agar. Taxonomic studies were carried out on the isolated Gram negative bacteria. Determination of antibiotic resistance profile of the Gram-negative bacteria was done by disc diffusion method. Ukpaka (Pentaclethra macrophylla) samples had the highest percentage occurrence of coliforms (100%). Faecal coliform were more prevalent in Ukpaka (20%) and Iru (16.67%). Klebsiella pneumonia was prevalent in the 3 of the fermented condiments (Iru, Ogiri and Ukpaka). Escherichia coli was the most frequent Gram-negative bacteria in Okpei samples. The relatively high recovery rates of Gram-negative bacteria shows possible contamination of fermented condiments by human pathogens. The isolates from Ukpaka showed the highest resistance (55.3%) to Cotrimoxazole. The effect of the resistance of Gram-negative bacteria to antibiotics could be transmission of resistant strains from farm to house, treatment failure and a limited choice of antibiotics used for treatment.

Prevalence of Antibiotic Resistant Bacteria in Nigerian Fermented Food Condiments

Food borne diseases remain a growing public health problem gotten through the consumption of contaminated food and water. A world health organization report, 2015 estimated 600million episodes of illness due to contaminated food worldwide. Amongst all age groups, Africa bore the greatest burden of diarrhoeal diseases. Gram-negative bacteria have become a significant challenge to the control of infection as a result of acquisition of antibiotic resistant genes. This is especially of concern in Nigeria where fermented condiments are important part of daily meals and sometimes consumed without cooking. This work thus identifies Gram negative bacteria from fermented condiments and evaluates the antibiotic resistance profile of the bacterial isolates. The fermented condiments- Iru (Parkia biglobosa) (67), Ogiri-igbo (Ricinus communis) (58), Ukpaka (Pentaclethra macrophylla) (22) and Okpei (Prosopis africana) (42), were obtained from markets in Abuja, Gboko, Lokoja, Okenne, Abeokuta, Ibadan, Ijebu-Ode, Ilorin, Lagos, Ondo and Ore. Coliform and faecal coliform test was done. Isolation of the Gram-negative bacteria was done using MacConkey agar. Taxonomic studies were carried out on the isolated Gram negative bacteria. Determination of antibiotic resistance profile of the Gram-negative bacteria was done by disc diffusion method. Ukpaka (Pentaclethra macrophylla) samples had the highest percentage occurrence of coliforms (100%). Faecal coliform were more prevalent in Ukpaka (20%) and Iru (16.67%). Klebsiella pneumonia was prevalent in the 3 of the fermented condiments (Iru, Ogiri and Ukpaka). Escherichia coli was the most frequent Gram-negative bacteria in Okpei samples. The relatively high recovery rates of Gram-negative bacteria shows possible contamination of fermented condiments by human pathogens. The isolates from Ukpaka showed the highest resistance (55.3%) to Cotrimoxazole. The effect of the resistance of Gram-negative bacteria to antibiotics could be transmission of resistant strains from farm to house, treatment failure and a limited choice of antibiotics used for treatment.

Bactericidal Activity of a Cationic Peptide on Neisseria meningitidis.

The increasing prevalence of antibiotic resistant bacteria has raised an urgent need for substitute remedies. Antimicrobial peptides (AMPs) are considered promising candidates to address infections by multidrug-resistant bacteria through new mechanisms of action that require a careful evaluation of their performance. Identification of effective AMPs against Neisseria meningitidis, which represents a pathogen of great public health importance worldwide that is intrinsically resistant to some AMPs, such as polymyxin B. A cationic 11-residue peptide (KLKLLLLLKLK), referred to as poly-Leu, was synthesized and its antimeningococcal activity was compared to cecropin A and poly-P (KLKPPPPPKLK) through a variety of assays. Flow cytometry was used to measure propidium iodide uptake by N. meningitidis serotype B as an indicator of the effectiveness of each peptide when added to cultures at different concentrations. The addition of the poly-Leu peptide led to a 90.3% uptake of the dye with an EC50 value of 7.9 µg mL-1. In contrast, uptake was <10% in cells grown in the absence of peptides or with an identical concentration of cecropin and poly-Pro peptides. Electron micrographs indicated that the integrity of the cellular wall and internal membrane was impacted in relation to peptide concentrations, which was confirmed by the detection of released alkaline phosphatase from the periplasmic space due to disruption of the external membrane. Poly-Leu peptide demonstrated definitive antimicrobial activity against N. meningitidis.

Addressing the antibiotic resistance and improving the food safety in food supply chain (farm-to-fork) in Southeast Asia

Antibiotics are the compounds widely used to treat bacterial infections in human and variety of agricultural sectors including livestock farming, plants and crops, and aquaculture. However, rampant and uncontrolled use of antibiotics results in the emergence of resistant bacterial strains. Such resistant strains on the food chain possibly increase the risk of antibiotic resistant foodborne pathogens. Antibiotic resistant bacteria can reach human either directly via the contact with the infected animal or indirectly via the food chain through the consumption of contaminated food. Prevalence of antibiotic resistant bacteria in Southeast Asia region threatens the global public health as this region is regarded as a hotspot of antibiotic resistant bacteria. The risk of development of antibiotic resistance can be reduced only with appropriate regulation and policies. However, the lack of appropriate surveillance systems in this region leads to the absence of reliable national data on the level of antibiotics. To counteract the risk of antibiotic resistance, the World Health Organization (WHO) has published the global action plan on antimicrobial resistance which has been adopted by several countries in Southeast Asia.

Multiple-antibiotic resistance of Enterococcus faecalis in an endangered olive ridley sea turtle (Lepidochelys olivacea): A case report

There has recently been an alarming increase in the prevalence of antibiotic resistant bacteria in marine environments. In this study, an Enterococcus sp. was isolated from bacteriologic cultures of the elbow joint of an olive ridley turtle (Lepidochelys olivacea ). The enterococci isolate was identified at the species level as Enterococcus faecalis using PCR and the RAPID ID 32 STREP system. Analysis of the antimicrobial resistance patterns and the antibiotic-resistance genes of the E. faecalis isolated in this study revealed multiple-antibiotic-resistance (MAR). Specifically, the isolate presented resistance to doxycycline, enrofloxacin, erythromycin, neomycin, oxytetracycline, gentamicin, amikacin, ciprofloxacin, spiramycin, chloramphenicol, ceftiofur, and azithromycin. We also identified the tetracycline resistance gene tet(M) in the E. faecalis isolate. Further research into the antimicrobial resistance patterns of Enterococcus spp. should be conducted to promote the conservation of sea turtles.

Phenotypic and genotypic characteristics of Escherichia coli with non-susceptibility to quinolones isolated from environmental samples on pig farms

BackgroundIn the last decade, the growth of the pig-farming industry has led to an increase in antibiotic use, including several used in human medicine, e.g. (fluoro)quinolones. Data from several studies suggest that there is a link between the agricultural use of antibiotics and the prevalence of antibiotic-resistant bacteria in the pig farm environment, including (fluoro)quinolone resistance. This poses a threat to human and animal health. Our goal was to phenotypically and genotypically characterize 174 E. coli showing non-susceptibility to quinolones isolated from environmental samples from pig farms. Antimicrobial susceptibility testing (AST) was performed using the disk diffusion method. PCR and sequence analysis were performed to identify chromosomal mutations in the quinolone resistance-determining regions (QRDR) of gyrA and the isolates were screened for the presence of the plasmid-mediated quinolone resistance (PMQR) genes aac-(6')-Ib-cr, qepA, qnrA, qnrB, qnrC, qnrD and qnrS.Strain relatedness was assessed by phylogenetic classification and multilocus sequence typing (MLST).ResultsOf 174 isolates, 81% (n = 141) were resistant to nalidixic acid, and 19% (n = 33) were intermediately resistant. Overall, 68.4% (n = 119) were multidrug resistant. This study revealed a prevalence of 79.9% (n = 139) for gyrA QRDR mutations, and detected 21.8% (n = 38) isolates with at least one PMQR gene. The two most frequently detected PMQR genes were qnrB and qnrS (13.8% (n = 24) and 9.8% (n = 17, respectively). E. coli belonging to phylogenetic group A (48.3%/n = 84) and group B1 (33.3% /n = 58) were the most frequent. E. coli ST10 (n = 20) and ST297 (n = 20) were the most common STs.ConclusionsE. coli with non-susceptibility to quinolones are widespread among the environment of Swiss pig farms and are often associated with an MDR phenotype. In several cases these isolates possess at least one PMQR gene, which could spread by horizontal gene transfer. E. coli from pig farms have diverse STs, some of which are associated with human and animal disease.

Identification, Growth Profile and Probiotic Properties of Autochthonous Intestinal Bacteria of Sagor catfish (&lt;i&gt;Hexanematichthys sagor&lt;/i&gt;)

The prevalence of antibiotic resistant bacteria in aquaculture has reached alarming proportions and intensified the search for microbe derived antimicrobial compounds. This study isolated bacteria from the intestine of Sagor catfish (Hexanematichthys sagor) and screened it for antagonistic properties. Five out of 334 bacterial isolates inhibited growth of fish pathogens. The 5 bacterial strains included relatives of Shewanella haliotis, Myroides odoratimimus, Vibrio harveyi, Vibrio alginolyticus and Alcaligenes faecalis. The growth profiles and probiotic properties of these bacteria were examined. The results showed that the isolate 9 (3) 7.5.2.1, whose closest relative was S. haliotis exhibited growth and probiotic advantage compared to the other bacterial strains, such as highest doubling time and the ability to survive at all experimental temperatures (18 to 60℃) , and bile concentrations (0.01 to 1.00%) and pH (pH2 to 9) . While the bacteria with probiotic properties were successfully isolated. Further study is necessary to examine the efficiency of the probiotic candidate bacteria in boosting fish immunity against pathogens.