No description available.

It was the purpose of the present investigation to determine if sensitivity to other antibiotics can likewise be affected by subjecting S. aureus to heparin contact. It is of special interest in this problem to determine whether heparin in some manner affects the combining process of penicillin with the cells of several strains of S. aureus.

Supplementation of the diet with low concentrations of antibiotics stimulates the growth of poultry by affecting the intestinal flora. The bacterial flora of the small intestine of turkey poults was extensively analyzed in an attempt to correlate changes in populations with growth response. Lactobacillus species comprised almost 100% of the duodenal flora of two-week-old poults but there was no difference in species associated with antibiotic (zinc bacitracin, 55 ppm) treatment. The ileal flora also was predominantly lactobacilli (average 75% of the flora). The most common lactobacilli from the turkey intestinal tract were several previously undescribed Lactobacillus species followed by L. acidophilus, L. salivarius subsp. salivarius, L. fermentum, and L. plantarum. Antibiotic treatment resulted in a shift in the proportions of several of the unnamed Lactobacillus sp. Preliminary feed trials using two strains of lactobacilli that belonged to species that increased in numbers with antibiotic treatment did not stimulate growth when one-day-old birds were colonized with the strains. A probable explanation for the increase in growth is the effect of antibiotic treatment on the multiplication of bacteria in the small intestine. As the digesta move from the gizzard to lower ileum an average 16-fold increase in bacteria occurs in untreated birds. In antibiotic-treated birds the increase was only 2-fold. This inhibition of growth is not due strictly to cell lysis because there are no significant differences in microscopic counts, but the viable counts do decrease. As a corollary there is significantly less lactic acid in the lower ileum of antibiotic-fed birds. Antibiotics did not affect total microscopic or viable counts in the crop or ceca. The above experiments were all done with zinc bacitracin; however, the inhibition of bacterial multiplication was also observed with procaine penicillin. The conclusion from my data is that zinc bacitracin, and probably procaine penicillin, stimulate the growth of turkey poults by a general suppression of the small intestinal flora rather than by an effect on any individual bacterial species. / Ph. D.

Antibiotic resistance profiles of fecal coliform isolated from unchlorinated and chlorinated secondary effluent were determined. Of 332 fecal coliforms isolated from chlorinated effluent a mean of 48% were multiply antibiotic resistant. In contrast, of 347 fecal coliforms isolated from unchlorinated effluent a mean of 29% were multiply antibiotic resistant. Resistance to ampicillin, cephalothin, and carbenicillin were significantly higher in the former than the latter. Randomly selected isolates survived and/or grew in sterile and unsterile effluent retaining resistance patterns for 40 days. Resistance factors were transferred in laboratory medium at frequencies from 0 to 1.2 x 10⁻² (number of recombinants/number of recipients) and in sterile neutralized tertiary effluent at frequencies from 0 to 1.0 x 10⁻⁴. Resuscitative techniques were necessary for optimal recovery of fecal coliforms from effluent using selective media. Antibiotic resistance patterns of fecal coliforms isolated from unchlorinated and chlorinated effluent was not associated with chlorine or heavy metal resistance. Multiply antibiotic resistant fecal coliforms from chlorinated effluent were significantly less sensitive to lytic phage than multiply antibiotic sensitive fecal coliforms from unchlorinated effluent (p < .05). Using group discriminate analysis of data, phage typing techniques were shown to be a potential tool for tracing fecal contamination of groundwater.

Call number: LD2668 .T4 1986 T39 / Master of Science / Animal Sciences and Industry

Gene expression heterogeneity underlies critical bacterial phenotypes including antibiotic tolerance, pathogenesis, and communication. Though microbial population heterogeneity has been appreciated for decades, we still lack a complete view of single-cell gene expression and phenotypic states. Various tools, including bulk RNA-seq and proteomics, are available for probing all genes on a population-level. Conversely, fluorescent protein reporters and in situ hybridization can capture single-cell states but only for a limited number of genes. Single-cell RNA-sequencing (scRNA-seq), which can quantify expression of all genes with resolution for individual cells, has revolutionized studies of heterogeneous eukaryotic populations. However, adaptation to bacteria has been hindered by technical barriers. This thesis will describe the development of high-throughput scRNA-seq for bacteria and its application to uncover a distinct transcriptional state of rare antibiotic-tolerant cells called persisters. Chapter 2 presents prokaryotic expression profiling by tagging RNA in situ and sequencing (PETRI-seq), our novel scRNA-seq technology. I will detail how PETRI-seq was optimized to overcome bacteria-specific challenges, including lack of mRNA polyadenylation, thick cell walls, and extremely low mRNA abundance. Using combinatorial indexing, PETRI-seq uniquely barcodes tens of thousands of gram-negative and/or gram-positive cells in a single experiment at low cost. In proof-of-concept experiments, we show robust discrimination of E. coli growth phases and identification of rare prophage activation in S. aureus. PETRI-seq will be broadly useful for characterizing bacterial heterogeneity in many contexts. Chapter 3 describes an expansive investigation into antibiotic persistence in E. coli. When a population is treated with lethal antibiotics, persisters are rare cells that can survive the exposure by assuming a relatively dormant state. Understanding the gene expression state and molecular drivers of persistence has been a longstanding goal with major potential to inform drug development and clinical practice. We have applied PETRI-seq to multiple models of E. coli persistence and discovered a distinct transcriptional state underlying this phenotype. In parallel, we used genome-wide CRISPR-interference to probe the functional contribution of every gene to the persistence phenotype. We discovered multiple driver genes and pathways. Comprehensive validation established Lon protease and YqgE as key gene products modulating translation rate, post-starvation dormancy, and persistence. Our work is a major step in defining the physiological state of persistence and the molecular processes leading cells into this state. In all, this thesis demonstrates how a new generation of systems approaches, including scRNA-seq and CRISPR-interference, enable new discoveries about long-studied phenomena. The overarching approach is broadly applicable with potential to inspire a wide range of microbiology studies.

Ma, Hok Lun. / Thesis submitted in: December 2008. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 233-273). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese version) --- p.v / Tables of contents --- p.vi / Acknowledgement --- p.xvi / List of figures --- p.xvii / List of tables --- p.xxi / List of abbreviations and symbols --- p.xxviii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Respiratory illnesses in children --- p.1 / Chapter 1.1.1 --- Worldwide burden of childhood pneumonia --- p.1 / Chapter 1.1.2 --- Further mortality related to childhood pneumonia --- p.4 / Chapter 1.2 --- Etiology agent of childhood respiratory illnesses --- p.5 / Chapter 1.2.1 --- Difficulties in determining etiological agent --- p.5 / Chapter 1.2.2 --- Overall situation of etiological agents in childhood pneumonia --- p.6 / Chapter 1.2.3 --- Relationship between age and pathogens --- p.9 / Chapter 1.2.4 --- "Relationship between serotypes, carriage and invasiveness" --- p.11 / Chapter 1.2.4.1 --- Carriage and Invasiveness --- p.12 / Chapter 1.2.4.2.1 --- Carriage of S. pneumoniae and H. influenzae in children in Hong Kong --- p.12 / Chapter 1.2.4.2.2 --- "Serotypes, carriage and invasiveness in S. pneumoniae" --- p.14 / Chapter 1.2.4.2.3 --- "Serotypes, carriage and invasiveness in H. influenzae" --- p.17 / Chapter 1.3 --- Epidemiology of antibiotic-resistant pathogens --- p.18 / Chapter 1.3.1 --- Molecular typing methods --- p.18 / Chapter 1.3.2 --- Spread of antibiotic-resistant pathogens --- p.20 / Chapter 1.3.2.1 --- Spread of antibiotic-resistant S. pneumoniae --- p.26 / Chapter 1.3.2.1.1 --- Spread of penicillin-resistant S. pneumoniae --- p.26 / Chapter 1.3.2.1.1.1 --- Spread of Spanish-23F-1 --- p.27 / Chapter 1.3.2.1.1.2 --- Spread of Spanish-6B-2 --- p.28 / Chapter 1.3.2.1.1.3 --- Spread of antibiotic-resistant S. pneumoniae clones in Hong Kong --- p.28 / Chapter 1.3.2.1.2 --- Spread of cephalosporin-resistant S. pneumoniae --- p.29 / Chapter 1.3.2.1.3 --- Spread of macrolide-resistant S. pneumoniae --- p.30 / Chapter 1.3.2.1.4 --- Spread of fluoroquinolone-resistant S. pneumoniae --- p.31 / Chapter 1.3.2.2 --- Spread of antibiotic-resistant H. influenzae --- p.32 / Chapter 1.3.2.2.1 --- Spread of β-lactam-resistant H. influenzae --- p.32 / Chapter 1.3.2.2.2 --- Spread of macrolide-resistant H. influenzae --- p.33 / Chapter 1.3.2.2.3 --- Spread of fluoroquinolone-resistant H. influenzae --- p.34 / Chapter 1.4 --- Mechanism of antibiotic-resistance in respiratory pathogens --- p.36 / Chapter 1.4.1 --- Mechanism of antibiotic-resistance in S. pneumoniae --- p.37 / Chapter 1.4.1.1 --- Mechanism of penicillin- and cephalosporin-resistance in S. pneumoniae --- p.37 / Chapter 1.4.1.1.1 --- Penicillin-binding protein (PBP)-mediated mechanism --- p.37 / Chapter 1.4.1.1.2 --- PBP-independent mechanisms --- p.49 / Chapter 1.4.1.1.2.1 --- "Murine peptide branching genes, murMN operon" --- p.49 / Chapter 1.4.1.1.2.2 --- "Two-component system, CiaRH" --- p.50 / Chapter 1.4.1.1.2.3 --- "Putative glycosyltransferase, CpoA" --- p.52 / Chapter 1.4.1.1.3 --- RNA and protein expression studies on S. pneumoniae for β-lactam-resistance --- p.52 / Chapter 1.4.1.1.3.1 --- RNA expression in penicillin-sensitive S. pneumoniae --- p.53 / Chapter 1.4.1.1.3.2 --- Protein expression in penicillin-resistant S. pneumoniae --- p.53 / Chapter 1.4.1.2 --- Mechanism of macrolide- and lincosamide- resistance in S. pneumoniae --- p.54 / Chapter 1.4.1.3 --- Mechanism of tetracycline-resistance in S. pneumoniae --- p.55 / Chapter 1.4.1.4 --- Mechanism of fluoroquinolone-resistance in S. pneumoniae --- p.55 / Chapter 1.4.2 --- Mechanism of antibiotic-resistant in H. influenzae --- p.56 / Chapter 1.4.2.1 --- Mechanism of β-lactam-resistance in H. influenzae --- p.56 / Chapter 1.4.2.1.1 --- β-lactamase-producing H. influenzae --- p.56 / Chapter 1.4.2.1.2 --- β-lactamase-negative ampicillin-resistant (BLNAR) H. influenzae --- p.58 / Chapter 1.4.2.1.2.1 --- Relationship between amino acid substitutions in PBP3 and β-lactam- resistance --- p.58 / Chapter 1.4.2.1.2.2 --- Relationship between amino acid substitutions in AcrR and β-lactam-resistance --- p.60 / Chapter 1.4.2.2 --- Mechanism of macrolide-resistance in H. influenzae --- p.61 / Chapter 1.4.2.3 --- Mechanism of fluoroquinolone-resistance in H. influenzae --- p.64 / Chapter 1.5 --- Impact of vaccination --- p.65 / Chapter 1.5.1 --- H. influenzae type b vaccination --- p.65 / Chapter 1.5.1.1 --- Efficacy of Hib conjugate vaccine --- p.66 / Chapter 1.5.1.2 --- Herd immunity related to Hib conjugate vaccine --- p.66 / Chapter 1.5.2 --- Pneumococcal vaccination --- p.66 / Chapter 1.5.2.1 --- Vaccine efficacy and herd immunity of pneumococcal vaccines --- p.67 / Chapter 1.5.2.2 --- Development of conjugate vaccines with higher valency --- p.67 / Chapter 1.5.2.3 --- Serotype replacement --- p.67 / Chapter 1.5.2.4 --- Development of pneumococcal vaccines with new targets --- p.69 / Chapter 1.6 --- Objectives of this study --- p.70 / Chapter Chapter 2 --- Materials and methods --- p.72 / Chapter 2.1 --- Collection and Identification of microorganisms --- p.72 / Chapter 2.1.1 --- Collection of S. pneumoniae and H. influenzae --- p.72 / Chapter 2.1.2 --- Identification of S. pneumoniae and H. influenzae --- p.73 / Chapter 2.2 --- Serotyping of S. pneumoniae and H. influenzae --- p.74 / Chapter 2.2.1 --- Serotyping by polymerase chain reaction (PCR) --- p.74 / Chapter 2.2.1.1 --- Preparation of crude DNA extract --- p.74 / Chapter 2.2.1.2 --- Screening for common serotypes by multiplex PCR --- p.74 / Chapter 2.2.1.3 --- Composition of PCR Mix --- p.77 / Chapter 2.2.1.4 --- Serotyping PCR conditions --- p.81 / Chapter 2.2.1.5 --- Gel Electrophoresis --- p.81 / Chapter 2.2.2 --- Serotyping by serum agglutination --- p.82 / Chapter 2.3 --- Antimicrobial susceptibility testing --- p.83 / Chapter 2.4 --- Clonal analysis of penicillin- and cephalosporin-resistant S. pneumoniae --- p.87 / Chapter 2.4.1 --- Pulsed-field Gel Electrophoresis (PFGE) --- p.87 / Chapter 2.4.1.1 --- Preparation of agarose plugs for PFGE --- p.87 / Chapter 2.4.1.2 --- Lysis of bacteria in agarose plugs --- p.89 / Chapter 2.4.1.3 --- Digestion of chromosomal DNA by restriction enzyme --- p.89 / Chapter 2.4.2 --- Multi-locus sequence typing (MLST) --- p.90 / Chapter 2.4.2.1 --- PCR amplification of house-keeping genes in MLST --- p.90 / Chapter 2.4.2.1.1 --- Preparation of DNA from agarose plugs --- p.92 / Chapter 2.4.2.1.2 --- Composition of PCR Mix --- p.92 / Chapter 2.4.2.1.3 --- MLST PCR conditions --- p.92 / Chapter 2.4.2.1.4 --- Gel Electrophoresis of MLST PCR products --- p.92 / Chapter 2.4.2.1.5 --- MLST PCR products purification --- p.93 / Chapter 2.4.2.2 --- Sequencing of housekeeping genes in MLST --- p.93 / Chapter 2.4.2.3 --- Sequencing analysis and sequence type (ST) determination in MLST --- p.94 / Chapter 2.4.3 --- Extended panel of antibiotic susceptibility testing on S. pneumoniae with known STs --- p.94 / Chapter 2.5 --- Analysis on potential penicillin- and cephalosporin-resistance mechanisms in S. pneumoniae --- p.96 / Chapter 2.5.1 --- Sequencing of potnetial penicillin- and cephalosporin- resistance determinants in S. pneumoniae --- p.96 / Chapter 2.5.1.1 --- Primer design of penicillin-binding protein (PBP) genes --- p.96 / Chapter 2.5.1.2 --- Primer design of non-PBP resistance determinants --- p.100 / Chapter 2.5.1.3 --- PCR amplification and sequencing of resistant determinants --- p.100 / Chapter 2.5.1.4 --- Sequence analysis --- p.100 / Chapter 2.5.2 --- Study on efflux mechanism of S. pneumoniae --- p.103 / Chapter 2.5.2.1 --- Modification of macrodilution for efflux assay --- p.103 / Chapter 2.5.2.2 --- Cefotaxime MIC determination with efflux inhibitors --- p.104 / Chapter 2.5.2.3 --- Determination of appropriate CCCP concentration --- p.105 / Chapter 2.5.2.4 --- Growth curve with efflux inhibitor --- p.105 / Chapter 2.5.3 --- Heteroresistance assay of S. pneumoniae --- p.106 / Chapter 2.5.4 --- "RNA expression study on penicillin- and cefotaxime-resistance determinants (pbp2x, pbpla and pbp2a) of S. pneumoniae" --- p.107 / Chapter 2.5.4.1 --- Growth of S. pneumoniae for RNA extraction --- p.107 / Chapter 2.5.4.2 --- RNA extraction and DNase digestion --- p.107 / Chapter 2.5.4.3 --- cDNA synthesis and real-time PCR --- p.108 / Chapter 2.6 --- Analysis on cephalosporin- and macrolide-resistance mechanisms in H. influenzae --- p.111 / Chapter 2.6.1 --- β-lactamase production of H. influenzae --- p.111 / Chapter 2.6.1.1 --- Nitrocefin Hydrolysis --- p.111 / Chapter 2.6.1.2 --- Screening for the presence of p-lactamase gene (blaTEM-1 and blaROB-1) by multiplex PCR --- p.111 / Chapter 2.6.2 --- PCR detection and sequencing of β-lactam- and macrolide- resistance determinants in H. influenzae --- p.113 / Chapter Chapter 3 --- Results of S. pneumoniae and H. influenzae children study --- p.116 / Chapter 3.1 --- Patient demographics of children study --- p.116 / Chapter 3.2 --- Serotype distributions --- p.117 / Chapter 3.2.1 --- Serotypes / serogroup distribution in S. pneumoniae --- p.117 / Chapter 3.2.2 --- Serotype distribution in H. influenzae children study --- p.120 / Chapter 3.3 --- Antibiotic susceptibilities and resistance antibiograms --- p.122 / Chapter 3.3.1 --- Antibiotic susceptibilities of S. pneumoniae --- p.122 / Chapter 3.3.2 --- Relationship between antibiotic resistance profiles and serotypes in S.pneumoniae --- p.126 / Chapter 3.3.3 --- Antibiotic susceptibilities of H. influenzae --- p.135 / Chapter 3.3.4 --- Antibiotic resistance profiles of H. influenzae --- p.138 / Chapter 3.4 --- Clonal analysis of penicillin- and cephalosporin-resistant S.pneumoniae --- p.139 / Chapter 3.4.1 --- Pulsed-field gel electrophoresis (PFGE) of S. pneumoniae --- p.139 / Chapter 3.4.2 --- Multi-locus sequence typing of S. pneumoniae --- p.141 / Chapter 3.5 --- Analysis of the penicillin- and cephalosporin-resistance determinants in S. pneumoniae --- p.143 / Chapter 3.5.1 --- "Sequence analysis of major pbp genes (pbp2x, pbpla and pbp2a)" --- p.143 / Chapter 3.5.2 --- "Sequence analysis of other potential penicillin- and cephalosporin- resistance determinants (pbp 1 b, pbp2b, pbp3, cpoA, ciaRH and murMN)" --- p.152 / Chapter 3.5.3 --- Sequence analysis of putative promoter sequences of pbp genes --- p.167 / Chapter 3.5.4 --- Efflux Inhibition Assay --- p.171 / Chapter 3.5.5 --- Heteroresistance Assay --- p.177 / Chapter 3.5.6 --- "RNA expression study on penicillin- and cephalosporin resistance determinants (pbp2x, pbpla and pbp2a)" --- p.179 / Chapter 3.6 --- Analysis of β-lactam-resistance determinants in H. influenzae --- p.185 / Chapter 3.6.1 --- β-lactamase production and blaTEM-1 promoter study --- p.185 / Chapter 3.6.2 --- "Sequence analysis of β-lactam-resistance determinants (ftsl, acrR genes, AcrAB-TolC efflux pump)" --- p.188 / Chapter 3.6.2.1 --- Sequence analysis offtsl --- p.188 / Chapter 3.6.2.2 --- Analysis of acrR and AcrAB-TolC efflux pump --- p.189 / Chapter 3.7 --- "Analysis of macrolide-resistance determinants in H, influenzae (AcrAB-TolC efflux pump, 23SrRNA, Ribosomal proteins L4 and L22)" --- p.199 / Chapter Chapter 4 --- Discussion on S. pneumoniae and H. influenzae children study --- p.204 / Chapter 4.1 --- Carriage rate of S. pneumoniae children collection --- p.204 / Chapter 4.2 --- Serotype distribution --- p.205 / Chapter 4.2.1 --- Serotype distribution and potential vaccine coverage in S. pneumoniae --- p.205 / Chapter 4.2.2 --- Serotype distribution in H. influenzae --- p.209 / Chapter 4.3 --- Antimicrobial resistance --- p.210 / Chapter 4.3.1 --- Antimicrobial resistance in S. pneumoniae --- p.210 / Chapter 4.3.2 --- Antimicrobial resistance in H. influenzae --- p.214 / Chapter 4.4 --- "Clonal analysis of high-level β-lactam-resistant S, pneumoniae" --- p.217 / Chapter 4.5 --- "β-lactam-resistance mechanisms in S, pneunomiae" --- p.220 / Chapter 4.6 --- Antimicrobial resistance mechanisms in H. influenzae --- p.224 / Chapter 4.6.1 --- β-lactam-resistance mechanism in β-lactamase-producing H. influenzae --- p.224 / Chapter 4.6.1.1 --- Variations in blaTEM-1 promoters in β-lactamase-producing H.influenzae --- p.224 / Chapter 4.6.1.2 --- β-lactam-resistance in β-lactamase-nonproducing H. influenzae --- p.225 / Chapter 4.6.2 --- Macrolide-resistance mechanisms in H. influenzae --- p.228 / Chapter Chapter 5 --- Conclusion and future studies --- p.230 / Chapter 5.1 --- "S, pneumoniae children study" --- p.230 / Chapter 5.2 --- H. influenzae children study --- p.231 / Chapter 5.3 --- Future studies --- p.232 / Bibliography --- p.233 / Appendix I 一 Sequence alignments and Tables --- p.274 / Appendix II 一 Materials and Methods --- p.313

Orientadoesr: Angela Maria Moraes, Silvia Yuko Eguchi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-07T08:22:07Z (GMT). No. of bitstreams: 1 Lucchesi_ElianeGama_M.pdf: 1203175 bytes, checksum: 28d918ad922300d0066ef3f03d052bdd (MD5) Previous issue date: 2006 / Resumo: Biofilme microbiano é definido como uma associação de células microbianas, fixadas a superfícies, bióticas ou abióticas, envolta por uma complexa matriz extracelular de substâncias poliméricas. Os biofilmes representam mais de 90% dos contaminantes existentes em sistemas aquosos, industriais, clínicos e ambientais. A resistência de microrganismos em biofilmes (sésseis) a biocidas é muito maior que a resistência de células livres (planctônicas), quando se compara seus antibiogramas. A rápida e correta avaliação do efeito de agentes antimicrobianos sobre os microrganismos sésseis é muito importante para a adequada seleção das ações corretivas a serem aplicadas em sistemas industriais contaminados. Atualmente, o sistema in vitro mais indicado para gerar, quantificar e erradicar biofilmes é o dispositivo MBECTM, de alto custo, desenvolvido por pesquisadores canadenses. O presente estudo visou o desenvolvimento de um sistema alternativo que fornecesse resultados análogos ao MBECTM, empregando esferas de vidro como suporte para o crescimento de biofilmes ao invés de placas de poliestíreno. Em amostras de três segmentos industriais diferentes (óleo de corte usado na usinagem de metais, amaciante ,. de roupas e caldo de cana) contaminados com microrganismos formadores de biofilmes, foram testadas sete formulações de biocidas em diversas concentrações, tanto no sistema desenvolvido quanto no dispositivo MBECTM. Os biocidas utilizados foram fomecidos pela IPEL Itibanyl Produtos Especiais Ltda, formulados com os seguintes princípios ativos: 2-bromo-2nitropropano-1 ,3-diol (BNP-115); 2-n-octíl-4isotiazolin-3-ona, 2-tiocianometiltiobenzotiazol, dimetílolurea, 5-cloro-2 metil-4isotiazolin-3-ona, 2-metil-4-isotiazolin-3-ona (FBP-124); 2-n-octil-4 isotiazolin-3-ona, dimetilolurea, 1,2-benzisotiazolin-3-ona (FBP-128); sódio-2-piridinatiol-n-óxido (FBP-140); hexahidro-1,3,5-tris(2-hidroxietil) s-triazina (BP-180); 2-bromo-2nitropropano-1,3-diol, 5cloJo-2metíl-4-isotiazolin-3-ona, 2-metil-4-isotiazolin-3-ona (BP-509);e 2-n-octil-4isotiazolin-3-ona, dimethylolurea, 3-iodo-2-propinil butil carbamato (FBP-417). A concentração inibitória mínima. (MIe) dos biocidas e suas concentrações mínimas de morte (CMM) foram determinadas para as bactérias planctônicas do fluido de corte, e a melhor relação custo/benefício foi observada para o biocida BNP-11,5, que apresentou MIC e CMM de 0,014% (v/v). Quanto às células sésseis, formadas em ambos os dispositivos utilizando-se fluido de corte contaminado como inóculo, o biocida de melhor relação custo/benefício foi o BP180. Nos ensaios com amaciante de roupas e caldo de cana, as melhores relações custo/benefício foram verificadas para os biocidas BNP-115, BP-180 e BP-509. A maturidade do biofilme foi muito importante para avaliar a eficácia dos biocidas. Verificou-se, durante o desenvolvimento. do trabalho, que para a concentração de erradicação (CE) do biofílme formado no dispositivo MBECTM ser semelhante às concentrações determinadas nas esferas de vidro, houve a necessidade de um periodo de incubação maior (72 horas) no MBECTM do que no sistema de esferas (48 horas). Os valores de CE determinados para o dispositivo MBEC TM, com 48 horas e 72 horas de incubação foram, respectivamente, 12 vezes maior que a concentração tradicional recomendada e de 30 a 125 vezes tal concentração, dependendo do biocida testado. Estes resultados evidenciaram que a maturidade do biofilme formado a partir do óleo de corte contaminado é atingida mais rapidarTIente no sistema de esferas de vidro do que no dispositivo MBEC TM, mostrando que é possível gerar um biofilme representativo da contaminação industrial em 48 horas no sistema alternativo desenvolvido, agilizando as ações corretivas e evitando ou minimizando principalmente os custos com o descarte das emulsões / Abstract: A microbial biofilm is defined as an association of microbial cells adhered to surfaces, biotic or abiotic, wrapped up in a complex extracellular polymeric matrix. Biofilms represent more than 90% of the existent contaminants in aqueous, industrial, and clinical systems, as well as in the environment. The resistance to biocides of microorganisms in biofilms (sessile cells) is much larger than that observed for cells in suspension (planktonic) when their antibiograms are compared. The fast and correct evaluation of the effect of antimicrobial agents on sessile microorganisms is very important for the appropriate selection of the corrective adions to be applied in contaminated industrial systems. Nowadays, the most indicated system to generate, quantify and eradicate biofilms is the MBECTM device, developed by Canadian researchers. The present study seeked the development of an altemative system to supply results similar to those obtained with the MBEC TM device, employing glass spheres as a support for biofilm growth instead of polystyrene plates. In samples of three different industrial segments (metal working cutting fluid, liquid fabric softener and sugar cane extract), seven commercial biocide formulations were tested in several concentrations, on "'rboth the developed system using glass spheres as support, and on the MBECTM device. The biocides employed were provided by IPEL ltibanyl Produtos Especiais Ltda, and were formulated with the following active agents: 2-brome-2nitropropane-1,3-diol (BNP-115); 2-n-octil-4isotiazolin-3-0ne, 2-tiocianometiltiobenzotiazol, dimethyilolurea, 5cloro-2metil-4-isotiazolin-3-one, 2-metil-4-isotiazolin-3-one (FBP-124); 2-n-octil-4 isotiazolin-3-0ne, dimethylolurea, 1,2-benzisotiazolin-3-0ne (FBP-128); sodium-2piridinatiol-n-oxide (FBP-140); hexahidro-1,3,5-tris(2-hidroxietil) s-triazine (BP-180); 2brome-2nitropropane-1 ,3-diol, 5-cloro-2metil-4-isotiazolin-3-one, 2-metil-4-isotiazolin-3-0ne (BP-509);e 2-n-octil-4-isotiazolin-3-0ne, dimethylolurea, 3-iodo-2-propinil butil carbamate (FBP-417). . The minimum inhibitory concentration (MIC) and minimum concentration of death (CMM) of the different biocides were determined for the cutting fluid planktonic bacteria and the best costlbenefit ratio was observed for BNP-115 biocide, which presented MIC and CMM values equal to 0,014% (v/v). Referring to sessile cells formed on both systems, when the contaminated cutting fluid was used as inoculum, the biocide presenting the best costlbenefit ratio was BP-180. In the tests with liquid fabric softener and sugar cane extract, the best costlbenefit ratios were verified when using BNP-115, BP-180 and BP-509 biocides. The maturity of the biofilm was very important to evaluate the effectiveness of the biocides. It was verified, during the development of the work, that for the eradication concentration (CE) of the biofilm formed in the MBEC TM device to be similar to the concentrations determined in the glass spheres, a larger incubation period was required (72 hours) in MBECTM than in the system constituted of spheres (48 hours). The determined values of CE using the MBECTM device, after incubation periods of 48 hours and 72 hours, were, respedively, 12 times higher than the traditional recommended concentration and from 30 to 125 times such concentration, depending on the tested biocide. These results evidenced that the biofilm formed trom the cutting oil reached its maturity more quickly in the glass spheres system than in the MBEC TM device, showing that it is possible to generate a representative biofilm starting from an industrial contaminated sample in 48 hours in the developed system, accelerating the proper corrective actions and avoiding or minimizing mainly the costs related to emulsion disposal / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química

Orientador: Angela Maria Moraes, Silvia Yuko Eguchi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-07T08:16:36Z (GMT). No. of bitstreams: 1 Capelletti_RaquelVannucci_M.pdf: 647054 bytes, checksum: c35c09b03ca4ad293e07ecb39071b2b4 (MD5) Previous issue date: 2006 / Resumo: Biofilmes são associações de espécies microbianas interdependentes, funcionando de forma complexa e coordenada como mecanismo de colonização de superfícies. Quando indesejavelmente instalados em uma planta industrial, os biofilmes contribuem para a contaminação de muitas áreas de processo, pois representam fontes de liberação e disseminação de microrganismos que podem deteriorar produtos, causando prejuízos financeiros e retrabalho, situação esta que pode ser prevenida e/ou controlada. No entanto, sua remoção representa um desafio, principalmente no que diz respeito à determinação do tipo e da dosagem adequada de biocida para este fim. Freqüentemente, a abordagem para a resolução deste problema é empírica. O presente trabalho teve por objetivo desenvolver um protocolo reprodutível para a formação de biofilmes em laboratório a partir de consórcios microbianos e a avaliação de sua susceptibilidade aos biocidas mais recomendados. Foram utilizados como inóculo microrganismos presentes em fluido de corte proveniente da indústria de usinagem de metais, por ser este um dos principais segmentos industriais sujeitos à formação de biofilmes. A metodologia adotada foi a recomendada para a utilização do dispositivo MBEC¿, um aparato amplamente empregado nas áreas médica e odontológica para o estudo de patógenos isolados, enfocando-se no estudo a influência de variáveis como tipo e concentração do inóculo, tempo e temperatura de incubação para a obtenção do biofilme e tempo de sonicação para desagregação do biofilme. Os resultados obtidos mostraram que o procedimento estabelecido para a obtenção in vitro de biofilmes foi plenamente satisfatório utilizando o inóculo constituído do fluido contaminado, e que tais biofilmes foram eficientemente erradicados na presença de biocidas não-oxidantes em concentrações 12 vezes superiores às normalmente empregadas. A temperatura de 25 ou 35°C e período de 48 h de incubação devem ser empregados para o desenvolvimento do biofilme e, para sua desagregação, recomenda-se efetuar a sonicação por 30 minutos. O isolamento das culturas puras a partir do consórcio microbiano original da amostra de fluido de corte, e o estudo dos biofilmes formados a partir das cepas isoladas não resultou na formação de biofilmes com número suficiente de células aderidas, indicando a ocorrência de seleção de cepas sem grande capacidade de adesão e de cepas fastidiosas e até mesmo não-cultiváveis, que requerem condições especiais de cultivo e que são essenciais para corresponder à flora original da amostra na formação do biofilme / Abstract: Biofilms are complex structures consisting of interdependent microbial species associations acting as surface colonization mechanism. Once undesirably installed at an industrial plant, biofilms contribute to contaminate many process areas, because they represent sources of microbial release and dissemination, which can deteriorate products, causing financial damages and work rebdoing, undesirable situations that can be controlled and/or prevented. However, biofilm removal represents a challenge, mainly referring to biocide type and dosage selection. Frequently, empiric approaches are used to solve this problem. The aim of the present work was to develop an in vitro experimental protocol for biofilm formation employing microbial consortia and to evaluate its susceptibility to recommended biocides. Microrganisms contaminating cutting fluid used in metalworking industry were employed as inoculum, since this is one of the main industrial segments subject to frequent biofilm formation. The adopted methodology was the recommended for the use of the MBEC¿ device thoroughly employed in the medical and dentistry areas for the study of isolated pathogenic microorganisms, and the study of the influence of variables such as inoculum type and concentration, incubation time and temperature for biofilm development, and sonication time for disaggregating the biofilms were focused. The achieved results showed that the established procedure for in vitro biofilm development was fully satisfactory when using the inoculum consisting of contaminated cutting fluid and that these biofilms were efficiently eradicated using non-oxidant biocide concentrations twelve times superior to those usually employed. Incubation temperature of 25 or 35°C and 48 h time period should be employed for biofilm development, while a 30 minute sonication period is recommended for disaggregating the biofilm. The isolation of the microorganisms in consortium, in the same cutting fluid, and their use for biofilm formation resulted in insufficient adhered cell numbers, indicating the occurrence of unadherent cells as well as unculturable strains, which require special culture conditions, and are essential for to reflect the original flora in the biofilm formation / Mestrado / Desenvolvimento de Processos Biotecnologicos / Doutor em Engenharia Química