The efficacy of USDA approved antimicrobials was evaluated in reducing Salmonella and Campylobacter on ground chicken frames and chicken breast fillets. Chicken frames dip treated with peracetic acid (PAA), lauric arginate (LAE), cetylpyridinium chloride (CPC) and acidified lactic acid (ALA) reduced Salmonella and Campylobacter counts in ground chicken frames without affecting meat pH and color. PAA and LAE reduced Salmonella by 0.9 log on d0 whereas on d1, PAA and CPC reduced by 1.4 and 0.9 log CFU/g respectively. PAA, ALA, propionic acid and LAE significantly reduced Campylobacter by 0.7, 1.0, 1.3, and 1.2 log CFU/g, respectively. On chicken breast fillets, 30 s application of PAA (0.04% and 0.07% pH 6.5) reduced loosely attached Salmonella by 0.5 and 0.8 log CFU/ml, respectively. ALA, octanoic acid and PAA reduced loosely attached Campylobacter by 1 log while all treatments except propionic acid were effective against strongly attached cells on chicken breast fillets.

Sodium lactate and acetic acid derivatives were evaluated for their impact on fresh Italian pork sausage links using commercial pork trimmings. Treatments included: 2.5% acetic acid (48.5%) –sodium lactate mixture (51.5%) (V), 2.5% sodium lactate (60% solids) (S), control –0.02% BHA/BHT (B) and negative control –seasoning only (C). Analysis over storage included total plate count (TPC), oxidative rancidity (TBARS), sensory analysis (descriptive and consumer), cooking loss, pH, and color. The S and V treatments had lower TPC (P<0.05) from days 5 through 14 when compared to B and C. TBARS values increased (P<0.05) for treatments C, S, and V while B was did not change (P>0.05) over time. While CIE a* surface values for redness generally decreased over time for all treatments, treatment B maintained more redness over the storage period. Of consumers tested, 85.6% rated all treatments between like slightly and like very much.

No description available.

The objective of this study was to determine if topical antimicrobials silver sulfadiazine and povidone-iodine ointment increase rates of healing of equine distal limb wounds that heal by second intention. Second, to determine the effect of bandaging with these topical antimicrobials. Six healthy adult horses were used to create thirty-six, 2.5 cm2 standardized full-thickness metacarpal/tarsal skin wounds. Each wound was exposed to a single treatment: 1.0 % silver sulfadiazine cream bandaged (SSD-B), 1.0 % silver sulfadiazine slow release matrix bandaged (SDX-B), 1.0% silver sulfadiazine slow release matrix not bandaged (SDX-NB), povidone-iodine ointment bandaged (PI-B), untreated control bandaged (C-B) and untreated control not bandaged (C-NB) until healing. Wound area, granulation tissue area and perimeter were measured with planimetry software from digital images obtained at each observation. Exuberant granulation tissue was excised when present. The days until healing, rate of healing parameter, rates of contraction and epithelialization were compared among groups using pair-wise analysis of least square means. The healing parameters and mean days to healing did not statistically differ between groups. Analysis of percent wound contraction and rate of epithelialization between groups was similar. Mean number of days to healing ranged from 83 (PI-B and C-B) to101 (SSD-B). All bandaged wounds produced exuberant granulation tissue requiring excision compared to none of the unbandaged. The identified rates of epithelialization and wound contraction found insignificant differences between antimicrobial treated versus untreated wounds. Similarly, rates of epithelialization and wound contraction found insignificant differences between bandaged versus unbandaged wounds. Topical povidone-iodine and silver sulfadiazine did not increase rates of healing under bandage. The 1.0% silver sulfadiazine slow release matrix not bandaged (SDX-NB) adhered well to dry wounds. Silver sulfadiazine slow-release matrix provides does not impede wound healing and provides good adherence to dry wounds not amenable to bandaging. / Master of Science

Beta lactam resistance producing isolates of Enterobacteriacea and non-Enterobacteriacea have emerged since more than seventy years ago (Abraham and Chain, 1940). They are known to cause both community and hospital-acquired infections. Resistance against carbapenem is primarily mediated by the production of enzymes that destroy the beta lactam antimicrobials, which are produced by these isolates involving the expression of serine and metalobetalactamase genes KPC, IMP, VIM, NDM-1 and OXA-48. Quinolone resistance is predominanty mediated by mutations in the qnrA, qnrB, qnrS, and aac-6-Ib genes. Carbapenemase-producing organisms especially Klebsiella pneumoniae carbapenemases (KPCs) emerged as important pathogens especially among critically ill patients causing significant morbidity and mortality. This study aims to determine the prevalence and types of 15 quinolone resistance and carbapenemases genes among different isolates from patients admitted to the University Hospital of Leipzig over a period of ten months. During the period from January 2011 through October 2011, a total of 50 carbapenemases isolates were recovered from patients of the University Hospital of Leipzig/ Germany. The isolates were identified by biochemical tests and their susceptibility to antimicrobials was determined by the microbroth dilution method according to ISO standard. The KPC, IMP, VIM, OXA-48, NDM-1, and aac-6-Ib genes as well as qnrA, qnrB, and qnrS genes were detected by multiplex PCR, respectively. Results showed that KPC gene was detected in 82% of the isolates while 8% were KPC negative. The qnrA, qnrS, IMP, NDM-1, and OXA-48 genes were not detected in any of the isolates while qnrB and VIM genes were found in 2%. On the other hand, aac-6-Ib gene was the most prevalent gene among the study isolates and composed a percentage of 96%. Results also showed that KPC, and aac-6-Ib genes were detected in isolates collected from urine, blood, wounds, swabs, sputum, tracheal secretions, biopsies, and anal smears, while VIM gene was detected in one isolate collected from blood. The qnrB gene was found in one isolate collected from urine specimen. The wide spread of carbapenem and quinolone resistance-producing organisms is a critical problem that complicates the treatment of infections resulting from these organisms. Necessary measures must, therefore, be taken to limit their spread, which include appropriate antibiotic treatment, control of hospital infections, observe of personal hygiene, and the use of appropriate methods of sterilization and disinfection to prevent the dissemination of these organisms. Keywords: Resistance, carbapenemases, QRDR, multiplex PCR, antimicrobials

Master of Science / Food Science / Kelly J.K. Getty / Listeria monocytogenes has the potential to contaminate ready-to-eat (RTE) meat and poultry products. Listeria monocytogenes contamination is a hazard that can potentially occur after post-lethality treatment in a processing environment during slicing or packaging of RTE meat products. United States Department of Agriculture’s Food Safety and Inspection Service (USDA/FSIS) requires facilities to have intervention strategies to demonstrate control of this pathogen in RTE meat and poultry products. FSIS categorizes different intervention strategies into Alternative 1, 2, or 3. If an establishment chooses Alternative 1, it must use a post-lethality treatment that reduces or eliminates microorganisms on the product and an antimicrobial agent or process that suppresses or limits the growth of L. monocytogenes. If an establishment chooses Alternative 2, it can either use a post-lethality treatment or an antimicrobial agent or process that suppresses or limits growth of L. monocytogenes. Under Alternative 3, the establishment must have a detailed sanitation program as its intervention strategy. As establishments increase the number of interventions or change from Alternative 3 to 2 to 1, the frequency of FSIS sampling of RTE meat and poultry products for safety and wholesomeness decreases. The effectiveness of post-package decontamination technologies such as high-pressure processing, ultraviolet C light, and pre/post-package surface pasteurization have been researched for controlling L. monocytogenes in RTE products. Formulating meat products with antimicrobial additives such as lactates, sodium lactate and sodium diacetate, potassium lactate and sodium diacetate, sodium levulinate, lauric arginate, glucono-delta-lactone, or organic acids is another common approach to control L. monocytogenes in RTE meat products. Also, a combination of sodium lactate and sodium diacetate in a formulation is an acceptable antimicrobial strategy to provide Alternative 2 status. Bacteriocins such as nisin can also be added to the formulation of RTE meat and poultry products for controlling L. monocytogenes. In addition nisin can be applied as packaging film coating. Another approach for controlling L. monocytogenes in products such as jerky, kippered steaks, snack sticks and turkey tenders is the use of packaging environments and holding times prior to shipping. In conclusion, there are various approaches for controlling L. monocytogenes in RTE meat and poultry products post-lethality and processors should consider these options rather than relying on sanitation alone.

Natural antimicrobials are peptides that are essential components of the innate immune system, providing broad-spectrum protection against bacteria, yeasts and some viruses. In addition to their innate immune activity, they exhibit properties suggesting they interact with the adaptive immune system. These functions imply they may be of particular importance in pregnancy. Intrauterine infection is responsible for approximately one third of cases of preterm labour, and normal labour is considered an inflammatory process, associated with leukocyte invasion of the uterine tissues and increased cytokine production. Little is known, however, about natural antimicrobial expression in pregnant reproductive tract. The aim of this thesis was thus to characterize natural antimicrobial production in pregnancy. The study focused on two main areas - the lower genital tract, comprised of the vagina and cervix; and the innermost fetal membrane, the amnion. In the lower genital tract, levels of natural antimicrobials were determined in samples of cervicovaginal secretions collected from pregnant women, using enzyme linked immunosorbance assay (ELISA). In addition Taqman quantitative PCR and ELISAs were used to investigate natural antimicrobial production by cell lines derived from endocervical, ectocervical and vaginal epithelium. It was found that elafin and secretory leucocyte protease inhibitor (SLPI) were found at high concentrations in cervicovaginal secretions, but levels were diminished in women with the common vaginal infection bacterial vaginosis (p<0.05). Cells derived from the vaginal epithelium expressed greater amounts of elafin than cervically derived cells. However, elafin and SLPI production could be stimulated in endocervical cells by the bacterial product lipopolysaccharide, a response that was not seen in the vaginal cell line. Natural antimicrobial production in the amnion was examined in tissue explants and primary cultured amnion cells, using a combination of Taqman PCR and ELISAs. In addition, cDNA microarray was carried out to investigate factors controlling amniotic antimicrobial production, and the involvement of signalling pathways was studied using specific pathway inhibitors. It was shown that the amnion expressed five antimicrobials: human beta defensins (HBD) 1, 2 and 3, SLPI and elafin. Expression of HBD2 was significantly upregulated following normal labour (p<0.05), with production in primary amnion epithelial cells dramatically increased by IL-1ß. The pattern of HBD2 expression in response to IL-1ß was biphasic, which suggested involvement of a secondary gene product. Several putative influential factors were identified by cDNA micorarray, including the NF-kappaB cofactor NFkappaBinhibitorζ. Its relationship to HBD2 was explored. The involvement of both NF-kappaB and mitogen activated protein (MAP) kinase p38 signalling appeared crucial in the response. This work has shown that natural antimicrobials are expressed by both the lower genital tract, where infections that are associated with preterm labour originate, and in the amnion, which is the fetus last line of defence to infection. They may have an important role in the prevention of infection associated preterm labour. Further characterization of these responses may increase understanding of the physiology, and pathophysiology of labour, and lead to strategies for the prevention of premature delivery.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Antimicrobial resistance is one of the major problems faced by the medical industry today. The ability of bacteria to rapidly acquire resistance against antibiotics and the over prescription and inappropriate use of antibiotics further exacerbate this crisis. Few new antimicrobials are, however, making it through the drug discovery pipeline. The search and development of novel and effective antimicrobials is therefore of the utmost importance. Lantibiotics are ribosomally synthesized cationic antimicrobial peptides with extensive post-translational modifications. They are active against a wide range of Gram-positive bacteria, including antibiotic-resistant strains. They are characterized by the presence of lanthionine and methyllanthionine rings and have been suggested as alternatives or for use in conjunction with antibiotics against resistant pathogens. Staphylococcus aureus is the most common bacteria isolated from skin and soft tissue infections (SSTIs). Strains of S. aureus have emerged with resistance against antibiotics with the most common being methicillin-resistant S. aureus (MRSA). Several lantibiotics are active against MRSA in vivo and have even shown superior activity to traditional antibiotics. Lantibiotics therefore show much promise for the treatment of SSTIs caused by resistant- and non-resistant S. aureus. In this study the bacterially diverse soil of the Fynbos in the Western Cape was screened for novel antimicrobials. Two antimicrobial producing Bacillus strains were isolated, Bacillus clausii AD1 and Bacillus amyloliquefaciens AD2. Both of these strains produce lantibiotics with B. clausii AD1 producing a known lantibiotic, clausin. B. amyloliquefaciens AD2 produces a novel two-component lantibiotic which was designated amyloliquecidin. The lantibiotic operon of amyloliquecidin was sequenced and annotated. All the genes required for successful production of amyloliquecidin are present in the operon. Amyloliquecidin was characterized in vitro and along with clausin is active against clinical strains of S. aureus (including MRSA), Enterococcus spp., Listeria spp. and beta-haemolytic streptococci. Amyloliquecidin has remarkable stability at physiological pH compared to nisin and clausin. A comparative in vivo murine infection model was used to evaluate the effectiveness of amyloliquecidin, nisin, clausin and Bactroban (commercial S. aureus topical treatment) in treating wound infections caused by S. aureus. All the lantibiotics proved to be just as effective as the Bactroban treatment. Furthermore, the tested lantibiotics did not have a negative influence on the wound closure rates of infected and non-infected wounds. Bactroban had a negative effect on wound healing compared to the lantibiotics. To our knowledge amyloliquecidin is the third two-component lantibiotic isolated from Bacillus. This study represents the first to test the effectiveness of amyloliquecidin in vivo and is one of a handful to test lantibiotics as topical treatments. / AFRIKAANSE OPSOMMING: Antimikrobiese weerstandbiedende bakterieë is op die oomblik een van die grootste probleme in die mediese veld. Die antibiotika krisis word vererg deur die vermoë van bakterieë om vinnig weerstand op te bou teen antibiotika, asook die alledaagse misbruik van antibiotika. Daar is ook ʼn tekort in die hoeveelheid antibiotika wat na die finale fases van ontwikkeling gaan. Om die oorhand teen antibiotika-weerstandige bakterieë te kry is dit van uiterste belang dat meer effektiewe antibiotika ontdek word. Lantibiotika is kationiese antimikrobiese peptiede wat deur die ribosoom gesintetiseer word en bevat ʼn verskeidenheid van modifikasies wat na translasie ingebou word. Hulle word gekarakteriseer deur lanthionien en metiellanthionien ringe. Lantibiotika is aktief teen ʼn verskeidenheid Gram-positiewe bakterieë en kan in kombinasie met antibiotika, of as alternatief gebruik word. Staphylococcus aureus is die mees algemene bakterium wat geassosieer word met vel en sagte weefsel infeksies (VSWIs). Staphylococcus aureus met weerstand teen antibiotika is ook al geïsoleer, die mees algemene weerstandige ras is methisillien-weerstandige S. aureus (MWSA). Lantibiotika is wel aktief teen MWSA in vitro en in vivo, met van hulle wat tot beter aktiwiteit as die voorgeskrewe antibiotika het. Lantibiotika kan dus gebruik word as behandeling vir VSWIs wat veroorsaak word deur weerstandige S. aureus, asook teen nie-weerstandige rasse. In hierdie studie was die bakteriese diverse grond van die Fynbos in die Wes-kaap ondersoek vir bakterieë wat antimikrobiese middels produseer. Twee Bacillus rasse, Bacillus clausii AD1 en Bacillus amyloliquefaciens AD2, wat antimikrobiese middels produseer, is geïsoleer. Bacillus clausii AD1 produseer ʼn bekende lantibiotikum, naamlik clausin. Bacillus amyloliquefaciens AD2 produseer ʼn nuwe twee-komponent lantibiotikum, amyloliquecidin. Die lantibiotikum operon wat verantwoordelik is vir die produksie van amyloliquecidin is geïdentifiseer en geannoteer. Die operon bevat al die gene benodig vir die biosintese van amyloliquecidin. Amyloliquecidin is in vitro gekarakteriseer en het aktiwiteit teen ʼn verskeidenheid Gram-positiewe bakterieë. Amyloliquecidin en clausin is aktief teen S. aureus (insluitend MWSA), Enterococcus spp., Listeria spp. en beta-hemolitiese streptococci wat vanaf infeksies geïsoleer is. Amyloliquecidin is baie stabiel by filologiese pH en aansienlik meer stabiel as nisin en clausin. Die effektiwiteit van nisin, clausin en amyloliquecidin in die behandeling van muis vel infeksies veroorsaak deur S. aureus was vergelyk met die kommersiële behandeling Bactroban. Al drie lantibiotika het die verspreiding van S. aureus met die selfde effektiwiteit as Bactroban belemmer. Geen van die lantibiotika het ʼn negatiewe effek op wond genesing nie. Bactroban, inteendeel, belemmer wond genesing. So ver ons weet is amyloliquecidin die derde twee-komponent lantibiotikum wat uit Bacillus geïsoleer is. Die studie is ook die eerste om die effektiwiteit van amyloliquecidin in vivo te rapporteer, asook ook een van die min studies wat kyk na lantibiotika as behandeling vir topikale infeksies.

Foodborne pathogens are a threat to public health worldwide. Because many consumers prefer natural compounds to synthetic additives, research on safe plant-derived compounds with antimicrobial activity against foodborne pathogens is vital. The aim of this investigation was to evaluate the antimicrobial activities of plant essential oils (oregano, cinnamon, lemongrass), their active components (carvacrol, trans-cinnamaldehyde, citral) and plant-extracts such as green tea, apple skin extract, black and decaffeinated black tea, grapes seed and pomace extracts against foodborne bacteria. Salmonella enterica serotype Typhimurium DT104, and serotype Newport, were selected conducting an antibiotic screening on 23 Salmonella isolates using seven antibiotics to determine antibiotic resistance. Listeria monocytogenes (strain 101M; beef and pork sausage isolate; resistant to antimicrobials in past investigations) was included to represent gram-positive bacteria. Escherichia coli O157:H7 virulent isolates (932- apple juice isolate; ATCC 35150- human isolate; F4637- sprouts isolate; used as a cocktail) were selected after conducting a Multiplex PCR over nine E. coli O157:H7 isolates to detect shiga-toxin 1 and 2 genes. All antimicrobials were evaluated in vitro in phosphate buffered saline. In general, all pathogens were more susceptible to essential oils and their active components, than powder extracts. The most active antimicrobials from each category were directly applied on foods. The activity of oregano oil (0.5%) and green tea (3%) was evaluated against S. Typhimurium on chicken and S. Newport on tomatoes and sprouts, and the results showed that oregano oil was more effective. In addition, baby spinach leaf samples inoculated with green fluorescent protein labeled S. Newport were examined under confocal scanning laser microscope before and after antimicrobial treatments. Antimicrobial experiments against L. monocytogenes on sprouts, ham and bologna, carvacrol at 0.5% and grape seed extract at 3% were used and carvacrol showed better activity. Antimicrobial activity against E. coli O157:H7 was tested on romaine lettuce, spinach and ground beef using oregano oil at 0.5% and green tea at 3%. Both compounds were effective showing no recovery of E. coli O157:H7 from lettuce and spinach; however, was not reduced in ground beef. Antimicrobial plant compounds have the potential for reducing foodborne pathogenic bacteria on/in various foods.

A piscicultura vem se destacando no âmbito nacional, uma vez que o Brasil apresenta uma significante disponibilidade de recursos hídricos e condições geográficas e climáticas favoráveis, que permitem a criação de espécies exóticas e nativas. Devido ao intuito comercial e financeiro, os produtores utilizam o sistema de produção em cativeiro, que constitui em um ambiente favorável à disseminação de doenças, devido à maior densidade populacional dos animais, com o agravante de que o ambiente aquático propicia a proliferação de doenças infecciosas, Desta forma, o uso de medicamentos veterinários constitui-se num recurso importante para amenizar e/ou solucionar este problema, com destaque ao emprego de antimicrobianos da classe das quinolonas e sulfonamidas, por exemplo. A principal via de administração desses medicamentos é por ingestão oral através da ração. Portanto, a incorporação de fármacos na ração é um aspecto crítico e de grande importância quando se visa a garantia da dose de tratamento dos animais, bem como, os riscos relacionados à contaminação ambiental decorrentes de eventual lixiviação dos fármacos da ração para a água. Frente a isso, métodos analíticos voltados para a quantificação de fármacos na ração são imprescindíveis. Diante da vantagem de se contar com um método analítico versátil, capaz de ser aplicado à determinação simultânea de diferentes fármacos, o emprego da eletroforese capilar constitui numa promissora alternativa. Assim, este trabalho teve como objetivo desenvolver e validar um método para análise de seis quinolonas (ciprofloxacino, difloxacino, ofloxacino, ácido oxolínico, flumequina e enrofloxacino) e quatro sulfonamidas (sulfametazina, sulfadimetoxina, sulfametoxazol e sulfatiazol) simultaneamente por eletroforese capilar. Para isso, foi utilizado um capilar de sílica fundida, de 50 cm de comprimento efetivo e 75 ?m de diâmetro interno e eletrólito de corrida composto por uma solução de borato de sódio na concentração de 40 mmol L-1, 15% de metanol e pH 8,5, corrente de 60 ?A, temperatura de 35 °C e detecção em 255 nm. Nessas condições, houve a separação dos dez fármacos em menos de 20 minutos. Os parâmetros de desempenho analítico, linearidade, precisão, exatidão, limite de quantificação, seletividade e robustez foram avaliados e estão de acordo com os requisitos preconizados pelos guias oficiais. O método foi aplicado para quantificar os fármacos na ração após a incorporação e no estudo de lixiviação dos fármacos. Após 10 minutos de exposição na água, houve uma perda significativa de CIPRO (11%) e MTZ (16%), correspondendo a 1,650 mg g-1/peixe/dia e 2,400 mg g-1/peixe/dia, respectivamente. Assim, a lixiviação mostrou ser um fator que deve ser considerado na terapêutica dos animais na piscicultura, uma vez que pode contribuir para ineficiência do tratamento, resistência bacteriana e prejudicar a qualidade da água. / Fish farming has been prominent at the national level, since Brazil has a significant availability of water resources and favorable geographical and climatic conditions that allow the creation of exotic and native species. Due to commercial and financial purposes, producers use the captive production system, which is an environment conducive to the spread of diseases, due to the greater population density of the animals, with the aggravating circumstance that the aquatic environment leads to the proliferation of infectious diseases. Thus, one of the technologies used to solve this problem is the use of veterinary drugs, in which antimicrobials of the quinolones and sulphonamides class. The main route of administration of these drugs is by oral ingestion through feed. The incorporation of drugs in feed is a critical aspect and of great importance when it comes to a guarantee of the dose of treatment of the animals, as well as the risks related to environmental contamination resulting from leaching of the drugs from the feed to a water. Therefore, analytical methods for the quantification of drugs in feed are essential. Given the advantage of having a versatile analytical method capable of being applied to the simultaneous determination of different drugs, the use of capillary electrophoresis constitutes a promising alternative. In this context, the aim of this study was to develop and validate a method for the analysis of six quinolones (ciprofloxacin, difloxacin, ofloxacin, oxolinic acid, flumequine and enrofloxacin) and four sulfonamides (sulfamethazine, sulfadethoxine, sulfamethoxazole and sulfathiazole) simultaneously by capillary electrophoresis. For this, a fused silica capillary of 50 cm in effective length and 75 ?m internal diameter and running electrolyte composed of a sodium borate solution in the concentration of 35 mmol L-1, 15% of methanol and pH 8.5, current 60 ?A, temperature of 35 ° C and detection at 255 nm. Under final conditions, all analytes were separations in less than 20 minutes. The parameters of analytical performance, linearity, precision, accuracy, limit of quantification and detection, selectivity and robustness were evaluated and are in accordance with the requirements recommended by the official guides. The method was applied to quantify the drugs in the feed after the incorporation and in the study of the leaching of the drugs. After 10 minutes of exposure in the water, there was a significant loss of CIPRO (11%) and MTZ (16%), corresponding to 1,650 mg g-1/fish/day and 2,400 mg g-1/fish/day, respectively. Thus, leaching has been shown to be a factor that should be considered in the treatment of animals in fish farming, since it may contribute to inefficiency of treatment, bacterial resistance and impair water quality.