Antibiotic usage is on the rise in industrialized countries and as a result the prevalence of autoimmune and atopic diseases has risen. The use of antibiotics is connected to a depletion of the microflora located within the gastrointestinal tract. The microflora contains a variety of different bacterial species, including some that are probiotic species, Lactobacilli and Bifidobacteria, which have a beneficial effect on the host. Probiotic species of bacteria are important for immune function due to their ability to regulate oral tolerance, a state of unresponsiveness to antigens that have been introduced orally to the host. The goal of this study was to assess the effect of broad spectrum antibiotic treatment on the probiotic species Lactobacilli and the resulting effect on the induction of oral tolerization to the antigen ovalbumin. / Department of Biology

The work presented in this thesis is concerned with the effect of several antibiotics and quaternary ammonium sanitizers upon growth of lactic acid bacteria. Section I reports the purification of beta-lactamase from Lactococcus cremoris PR-108, by ion exchange chromatography, using the chromogenic substrate pyridine-2-azo-p-dimethylaniline (PADAC) as the enzymatic indicator. Section II reports a study of the influence of antibiotics on lactococcal growth, where the effects of incubation time, culture dilution and the use of seeded and spread agar plate techniques are investigated. These studies were extended, in section III, to include investigations of the effect of quaternary ammonium base sanitizer (Ster-bac) on lactic starters. In addition, this section describes an reverse phase high performance liquid chromatography assay for the detection of quaternary ammonium compounds in milk. / Graduation date: 1991

Probiotics are a live microbial supplement that reside within the intestinal tract and are considered normal flora. The Balb/c mouse model was used to determine if the elimination of probiotics, general LAB species, by antibiotics plays a role in the breakdown of oral tolerance leading to the generation of an immune response to oral antigens. A mouse model was developed for in vivo research regarding probiotic populations and the effect on the induction of oral tolerance. The Balb/c mouse was used to determine if the mouse model had a colonized intestinal tract with probiotics followed by a reduction of probiotics that was done with orally administered antibiotics. After the reduction of probiotics, mice were fed oral antigen, ovalbumin, to determine that an immune response was not shown with oral antigen alone. After the mouse model was set up, mice were then fed oral antigen and then stimulated with immunizations to study the induction of oral tolerance and the possible effect of the absence of probiotics. The results indicated that mice with reduced probiotics and fed with oral antigen alone do not show an immune response. In contrast, mice fed with oral antigen followed by immunization indicate a higher OVA-specific serum IgG. This is evidence that correlates with clinical findings in disease states such as Crohn's Disease and Irritable Bowel Syndrome (IBD). / Department of Biology

Clostridium sordellii cause gas gangrene in man and animals, and more recently it has been implicated as a causal agent of diarrhea and enterotoxemia in domestic animals. This organism was once believed to cause pseudomembranous colitis (PMC) in humans, however, Clostridium difficile, not C. sordellii, was found to be the causative agent of this disease. It is now known that C. difficile produces two toxins, designated A and B, that are implicated in the pathogenesis of the disease. C. sordellii produces two toxins, designated HT (Hemorrhagic Toxin) and LT (Lethal Toxin), that are similar to toxins A and B of C. difficile. The goal of my research was to purify and characterize the two toxins of C. sordellii, and compare their properties to those of C. difficile. Toxin HT was purified from C. sordellii (VPI strain 9048) culture filtrate by ultrafiltration through an XM-100 membrane filter and immunoaffinity chromatography using a monoclonal antibody to toxin A of C. difficile as the ligand. Toxin LT was purified to 80% homogeneity by ultrafiltration on an XM-100 membrane filter and ion-exchange chromatography. Toxin HT migrated as a major band with molecular weight of 525,000 and a minor band at 450,000 on non-denaturing PAGE. By SDS-PAGE the molecular weight was estimated at 300,000. Isoelectric focusing indicated a pI of 6.1. Like toxin A, toxin HT was cytotoxic to cultured cells, lethal for mice, and elicited an accumulation of hemorrhagic fluid in rabbit ileal loops. Toxin LT exhibited properties similar to toxin B, although LT was about a 1000-fold less cytotoxic than toxin B. By SDS-PAGE the molecular weight was estimated at 260,000. Immunodiffusion analysis revealed a reaction of partial identity between these toxins and their amino-terminal sequences were very similar. Toxins HT and LT of C. sordellii have retained remarkable immunological similarities as well as physicochemical and biological properties with toxins A and B of Q. difficult however the toxins are not identical. / Ph. D.

Made available in DSpace on 2014-08-13T14:50:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-27Bitstream added on 2014-08-13T18:01:00Z : No. of bitstreams: 1 000749218.pdf: 1017688 bytes, checksum: 4223bbf012271b042bc6f6dc3a3fa8fb (MD5) / O presente estudo comparou a eficácia “in vitro” e “in vivo” da cefoperazona sódica, gentamicina e ciprofloxacino no tratamento intramamário de casos de mastite clínica bovina. Foram utilizadas 30 vacas com mastite clínica, não sistêmica, divididas em três grupos de dez animais. Em cada grupo foi utilizado um dos antimicrobianos citados, para o tratamento convencional da mastite (três aplicações a cada 12 horas) e o tratamento estendido (seis aplicações a cada 12 horas). Os principais micro-organismos isolados dos quartos mamários com mastite foram Staphylococcus aureus, Staphylococus spp., Streptocccus spp. e enterobactérias. A eficácia da cura clínica do tratamento convencional foi de 50% para o grupo tratado com cefoperazona sódica, 70% para o grupo tratado com gentamicina e 50% para o grupo tratado com ciprofloxacino. Para os mesmos grupos, a eficácia da cura clínica do tratamento estendido foi 90%, 100% e 80%, respectivamente. A eficácia da cura bacteriológica foi de 100% para o grupo tratado com cefoperazona sódica e de 90% para os grupos utilizando a gentamicina e ciprofloxacino no tratamento convencional. Para os mesmos grupos, foi observado 100% de cura bacteriológica para a gentamicina e 90% para os grupos com cefoperazona sódica e ciprofloxacino no tratamento estendido. Não foram encontradas diferenças estatisticamente significantes (P>0,01) para a cura clínica e cura bacteriológica dentro de cada grupo e entre os grupos de antimicrobianos, tampouco entre os tratamentos convencional e estendido dentro do mesmo grupo ou entre os grupos. Os resultados do presente estudo reforçam a importância da lactocultura e do teste de sensibilidade microbiana “in vitro” como respaldo para os tratamentos intramamários de vacas com mastite clínica. Inferiu-se também a boa eficácia na cura clínica e bacteriológica da cefoperazona sódica, gentamicina e ciprofloxacino no tratamento ... / This study compared the in vitro and in vivo efficacy of sodium cefoperazone, gentamicin and ciprofloxacin for the intramammary treatment of clinical mastitis in cows. Thirty cows suffering from non-systemic, clinical mastitis were divided into three groups of ten animals each. One of the above mentioned antibiotics was used in each group for conventional (i.e., three administrations of the drug, each 12 hours) and extended (i.e., six administrations of the drug, each 12 hours) treatments of mastitis. The most common microorganisms isolated from cows were Staphylococcus aureus, Staphylococus spp., Streptocccus spp. and enterobactéria. The efficacy of clinical cure of the conventional treatment was 50%, 70% and 50% for the groups treated with sodium cefoperazone, gentamicin and ciprofloxacin, respectively. Regarding the extended treatment, efficacy was 90%, 100% and 80%, for sodium cefoperazone, gentamicin and ciprofloxacin, respectively. Efficacy of bacteriological cure was 100% for sodium cefoperazone, and 90% for both gentamicin and ciprofloxacin using the conventional treatment. By using the extended treatment, efficacy of bacteriological cure was 100% for gentamicin and 90% for both cefoperazone and ciprofloxacin. Statistical differences (p>0.01) were not found in clinical or in bacteriological cure into the same group or among groups. Similarly, statistical differences between the conventional and extended treatments were not found. The results from this study reinforce the importance of performing microbiological culture of milk and in vitro antimicrobial sensitivity tests for supporting the intramammary treatment of clinical mastitis in cows. The clinical and bacteriological efficacy of sodium cefoperazone, gentamicin and ciprofloxacin in lactating cows was also observed in both conventional and extended treatments provided the use of sensitivity tests in vitro. Extended treatments should be used in selected cases of bovine mastitis

Made available in DSpace on 2014-08-13T14:50:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-13Bitstream added on 2014-08-13T18:00:51Z : No. of bitstreams: 1 000753071_20141210.pdf: 467641 bytes, checksum: 3558c6a799d74b315490c4c1c6a84e10 (MD5) Bitstreams deleted on 2014-12-12T11:34:16Z: 000753071_20141210.pdf,Bitstream added on 2014-12-12T11:34:47Z : No. of bitstreams: 1 000753071.pdf: 2884224 bytes, checksum: a67ab29ad51d31786e60184230c3b1b2 (MD5) / Staphylococcus aureus é considerado o agente etiológico mais importante da artrite séptica. Neste contexto, o objetivo geral deste trabalho foi investigar o potencial artritogênico de cepas padrão de S. aureus produtoras de superantígenos (SAgs) e testar a eficácia terapêutica da associação entre antibiótico e imunomodulador neste modelo. Camundongos C57BL/6 machos foram inicialmente infectados pelo plexo retro-orbital com as diferentes cepas. O desenvolvimento de artrite e sua gravidade foram acompanhados por 14 dias, através das seguintes determinações: peso corporal, escore clínico e incidência de artrite, alterações histopatológicas, número de unidades formadoras de colônias, expressão local de citocinas e subpopulação células por PCR em tempo real e produção de citocinas por células esplênicas. Os resultados foram organizados em 3 manuscritos. No primeiro, comparamos a capacidade artritogênica de 5 cepas produtoras de SAgs. Constatamos que as cepas ATCC 19095 SEC+, N315 ST5 TSST-1+ e S-70 TSST-1+ determinaram artrite grave, intermediária e discreta, respectivamente. No segundo trabalho caracterizamos a artrite causada pela cepa ATCC 19095 SEC+. Este tipo de artrite se caracterizou por elevado escore clínico associado à proliferação sinovial, inflamação intensa, formação de “pannus”, destruição da cartilagem e erosão óssea. A análise da expressão local de fatores de transcrição indicou expansão acentuada de células Th1 e Th17 nas lesões. No último manuscrito, avaliamos o efeito terapêutico da combinação do antibiótico bactericida cloxacilina com o imunomodulador tacrolimus. A administração destas duas drogas foi nemos eficaz no controle da doença do que o antibiótico administrado isoladamente / Staphylococcus aureus is considered the more important etiological agent of septic arthritis. In this context, the main objective of this work was to investigate the arthritogenic capacity of standard S. aureus strains, producer of superantigens (SAgs). We also tested the therapeutic effectiveness of an association antibiotic and an immunomodulatory drug in this model. C57BL/6 male mice were initially infected by retro-orbital plexus with different strains. Development and severity of arthritis were followed during 14 days, through determination of body weight, clinical score and incidence of arthritis, histopathological changes, determination of colony forming units, evaluation of local infiltration of Th subsets by real time PCR and cytokine production by spleen cells. The results were organized in three manuscripts. In the first one we compared the arthritogenic ability of 5 S. aureus strains. We found that the strains ATCC 19095 SEC+, N315 ST5 TSST-1+ and S-70 TSST-1+ determined severe, intermediate and discrete arthritis, respectively. In the second study we characterized the arthritis caused by the ATCC 19095 SEC+ strain. This type of arthritis was characterized by high clinical scores associated with synovial proliferation, intense inflammation, pannus formation, cartilage destruction and bone erosion. In the final manuscript we evaluated the therapeutic potential of the combination bewteen cloxacilin (bactericidal antibiotic) with tacrolimus (immunomodulator). The administration of these two drugs was less effective in controlling the disease than the antibiotic alone

Third molar surgery may be associated with a number of complications the most common of which are postoperative pain, swelling and trismus, and dry socket formation. The appearance of these post-operative sequelae is intimately related to the manifestations of inflammation in response to tissue injury. There is significant post-operative morbidity associated with these complications and it was thus the objective of this study to - investigate the effect of a combined antibiotic/anti-inflammatory intrasocket medication on post-operative pain, swelling and dry socket formation. The medication chosen for the study was Covomycin D®. Covomycin D® is a commercially prepared opthalmological preparation - each 1 millilitre contains 2 mg chloramphenicol, 5 mg neomycin sulphate and 0,5 mg dexamethasone. Nineteen subjects were included in the study after fullfilling certain criteria. All subjects were operated under general anaesthesia by the same surgeon. The patients were blinded to the side of the medication and were asked to complete a pain visual analogue scale and note the side of the worst swelling in the post¬operative period. All patients were followed up in the first week following surgery by an independent oral and maxillofacial surgeon who was also blinded to the side on which the medication was placed. The results showed a significant difference (p<0.6) in the pain experienced on the non-medicated compared to the medicated side on day one in eleven of the nineteen patients (57.9%). When the data was analysed over the six day postoperative period sixteen of the nineteen patients (84.2%) had significantly less pain on the medicated side compared to the non-medicated side (p<0.6). The swelling was reported as being worse on the non-medicated side in fourteen out of the nineteen patients (73.7%). Dry socket occurred in three out of nineteen patients or three out of thirty eight surgical extraction sites; an overall incidence of 7.9% or an incidence of 0% for the medicated side and an incidence of 15.8% on the non-medicated side i.e. all the dry sockets occurred on the non-medicated side. In conclusion, this double-blinded prospectve study, showed that the use of a combined antibiotic/anti-inflammatory intrasocket medication favourably influences the common adverse post-operative sequelae following the removal of lower third molars. / Dissertation (MChD (Chir Max-Fac Med))--University of Pretoria, 2007. / Maxillo-Facial and Oral Surgery / unrestricted

The purpose of this study is to find out that if antibiotic streptomycin decreases neuronal network activity or affects the pharmacological responses. The experiments in this study were conducted via MEA (multi-electrode array) technology which records neuronal activity from devices that have multiple small electrodes, serve as neural interfaces connecting neurons to electronic circuitry. The result of this study shows that streptomycin lowered the spike production of neuronal network, and also, sensitization was seen when neuronal network pre-exposed to streptomycin.

Diarrhoea, particularly infectious diarrhoea, in children below five years of age is recognised as one of the leading cause of morbidity and mortality throughout the world. This is especially true in residential areas of developing countries where there is substandard sanitation and overcrowding which are reservoirs for farther transmission. Shigellosis is endemic in developing countries and in Sub-Saharan Africa, including South Africa, a region where unique geographic, economic, political, sociocultural, and personal factors interact to create distinctive continuing challenges to prevention and control. Our study was undertaken to establish baseline information on incidences of Shigella, its serotype and resistant pattern of isolates from human faeces from residents of Johannesburg, South Africa. All stools received from January to April 2013 from the private health care system were cultured on standard media for isolation of Shigella and confirmed by standard biochemical reactions and serological method. Antibiotic sensitivity test was determined by the agar diffusion method. 11009 stool samples were assayed from patients aged between 22 days to 94 years with a 110 Shigella isolates yield, of which 47 (43%) were S. flexneri, 61 (55%) S. sonnei and 1 (1%) of S. dysentriae and S. boydii respectively. Majority of patients 76 (69%) were children between < 1 to 5 years old followed by those between 6 to 10 years 13(12%). Of the four species isolated from children of up to 10 years old, S. sonnie was confirmed in 52 cases (59%) and S. flexneri in 36 cases (41%). A total of 53 (48%) males and 57 (52%) females were infected. However, a hundred per cent susceptibility to ciprofloxacin and ceftriaxone but high levels of resistance to Co-trimoxazole (83%), tetracycline (72%), and ampicillin (26%) was noted. From the 110 isolates, 96 (87%) were resistant to one or more drugs while 14 (13%) were fully susceptible. These results show that S. sonnei followed by S. flexneri as predominating aetiology of shigellosis and Ceftriaxone and ciprofloxacin as effective drugs against all four Shigella species. / Health Studies / M. Sc. (Life Sciences)

Diarrhoea, particularly infectious diarrhoea, in children below five years of age is recognised as one of the leading cause of morbidity and mortality throughout the world. This is especially true in residential areas of developing countries where there is substandard sanitation and overcrowding which are reservoirs for farther transmission. Shigellosis is endemic in developing countries and in Sub-Saharan Africa, including South Africa, a region where unique geographic, economic, political, sociocultural, and personal factors interact to create distinctive continuing challenges to prevention and control. Our study was undertaken to establish baseline information on incidences of Shigella, its serotype and resistant pattern of isolates from human faeces from residents of Johannesburg, South Africa. All stools received from January to April 2013 from the private health care system were cultured on standard media for isolation of Shigella and confirmed by standard biochemical reactions and serological method. Antibiotic sensitivity test was determined by the agar diffusion method. 11009 stool samples were assayed from patients aged between 22 days to 94 years with a 110 Shigella isolates yield, of which 47 (43%) were S. flexneri, 61 (55%) S. sonnei and 1 (1%) of S. dysentriae and S. boydii respectively. Majority of patients 76 (69%) were children between < 1 to 5 years old followed by those between 6 to 10 years 13(12%). Of the four species isolated from children of up to 10 years old, S. sonnie was confirmed in 52 cases (59%) and S. flexneri in 36 cases (41%). A total of 53 (48%) males and 57 (52%) females were infected. However, a hundred per cent susceptibility to ciprofloxacin and ceftriaxone but high levels of resistance to Co-trimoxazole (83%), tetracycline (72%), and ampicillin (26%) was noted. From the 110 isolates, 96 (87%) were resistant to one or more drugs while 14 (13%) were fully susceptible. These results show that S. sonnei followed by S. flexneri as predominating aetiology of shigellosis and Ceftriaxone and ciprofloxacin as effective drugs against all four Shigella species. / Health Studies / M. Sc. (Life Sciences)