Staphylococcus lugdunensis and Staphylococcus schleiferi, two newly described species, have been isolated from numerous types of human infections. We compared the pathogenicity of 30 strains of S. lugdunensis, S. schleiferi, Staphylococcus epidermidis, Staphylococcus warneri, and Staphylococcus hominis, using a mouse model in which a foreign body preadhered with the test strain was implanted subcutaneously, followed by injection of the test strain. All five species of staphylococci produced abscesses. Staphylococcus epidermidis, S. schleiferi, and S. lugdunensis yielded species means of 76-91% abscess formation; 80-100% of the infected foreign bodies and tissues were culture positive. These three species were more virulent than S. warneri or S. hominis, which produced abscesses in 54 and 65% of mice, respectively; only 10-48% of the infected samples were culture positive. Transmission electron microscopy of pure cultures of selected strains showed that all species possessed glycocalyx. All species produced a variety of possible virulence factors, such as α and δ hemolysins, as well as the aggressins lipase and esterase. The production of exoenzymes did not always correlate with virulence as demonstrated by abscess formation in mice.

Orientador: Maria de Lourdes Ribeiro de Souza da Cunha / Banca: Elisabeth Loschagin Pizzolitto / Banca: Eduardo Bagagli / Resumo: Os estafilococos coagulase-negativa (ECN) estão entre os microrganismos mais envolvidos em infecções nosocomiais, principalmente em recém-nascidos (RN) prematuros e de baixo peso. Entre os fatores de risco para infecções por esses agentes, a produção de um polissacarídeo extracelular e a conseqüente formação do biofilme, permitindo aderência às superfícies plásticas e lisas de cateteres e outros dispositivos médicos desempenham um papel importante. Uma coleção de 100 amostras de ECN, sendo 50 isoladas de pontas de cateteres e 30 de hemoculturas obtidas de RN da Unidade Neonatal do Hospital das Clínicas da Faculdade de Medicina de Botucatu, UNESP e 20 obtidas de fossas nasais de portadores saudáveis foi analisada quanto à produção de biofilme pelos métodos do tubo (TM), ágar vermelho congo (CRA) e através do método quantitativo de aderência a placa de poliestireno (TCP). Esses métodos foram comparados com a pesquisa dos genes icaA, icaD e icaC envolvidos na produção de biofilme em ECN. Das 100 amostras de ECN estudadas, 82% foram positivas pela técnica de PCR, 82% pelo método do tubo, 81% pelo método da placa de poliestireno e 76% pelo CRA. O método de aderência ao tubo (TM) foi o teste que mostrou resultados mais confiáveis, com uma sensibilidade e especificidade de 100% e boa concordância quando comparado a técnica de PCR. Com o objetivo de determinar o papel do biofilme como fator de risco na ocorrência de infecções em RN, 130 amostras de estafilococos coagulasenegativa (ECN) isoladas de recém-nascidos (RN) internados na Unidade Neonatal do Hospital das Clínicas da Faculdade de Medicina de Botucatu foram identificadas e classificadas em significativas e contaminantes, baseado em dados clínicos e laboratoriais obtidos dos prontuários dos RN. Foram pesquisados fatores perinatais de risco para infecção, evolução clínica dos RN e antibiotico... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Coagulase-negative staphylococci (CNS) are most often associated with nosocomial infections, especially in premature and under weight newborns. The most important pathogenic factor of these microorganisms is the production of extracellular polysaccharide and the consequent formation of biofilm which facilitates their adherence to the surfaces of catheters and other medical devices. A total of 100 clinical isolates of coagulase-negative staphylococci (CNS) isolated from infected medical devices received from the Neonatal Unit, University Hospital, Botucatu Medical Schooll, including 50 isolated from catheter tips, 30 from blood cultures, and 20 collected from the nasal cavity of healthy subjects were investigated in order to evaluate the efficiency of three phenotypic methods of detection of biofilm formation, and also analyze the icaA, icaD and icaC genes, using the PCR method. The clinical isolates were screened by tissue culture plate (TCP), Tube method (TM), and Congo Red Agar (CRA) method. Of the 100 tested isolates, 82% were positive in the PCR method; in the TM, 82%; in the TCP assay, 81%; and 76% in CRA method. The method of adherence to the test tube was shown that more reliable results, with a sensitivity and specificity of 100% and good agreement when compared with the PCR technique. In order to determine the role of biofilm as a risk factor in the occurrence of infections in newborns 130 clinical isolates of CNS were identified and classified as significant and contaminant, based on clinical data obtained from the patients' reports. Perinatal risk factors for infection, clinical evolution and antibiotic therapy for the newborns were studied, as well as the detection of the genes responsible for the production of biofilm in CNS.Of the 130 clinical isolates of CNS, 66 (50.8%) were classified as clinically significant and 64 (49.2%) as contaminant... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2016-04-28T20:17:24Z (GMT). No. of bitstreams: 1 2007- Lidiane de Castro Soares.pdf: 1336181 bytes, checksum: 47680a74331a705e5ecd649c1639aa3f (MD5) Previous issue date: 2007-02-28 / Funda??o Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Coagulasenegative staphylococci (SCN) take part of normal microbiota. Although it has been considered saprophytic, nowadays there is a concern about its pathogenic potential.Nevertheless, all advance in SCN identification assays, these microorganisms are continually neglected in laboratorial routine of infectious diseases, because of the wide range of species. In spite of the difficulties, it is necessary to make an appropriated species identification in order to differentiate the potential pathogenic agents and to determine its antimicrobial susceptibility pattern. Resistance in SCN is related to the presence of mecA gene, which expresses a heterogeneous pattern that can be detected through diverse phenotypics tests. In this study, 72 SCN isolates obtained from external ear conducts of dogs, bovine mastitis and human nosocomial infections were evaluated. Staphylococcus xylosus was the most prevalent microorganism in animal and S. cohnii subsp.urealyticus in human sample. The antimicrobial resistance patterns were evaluated through disc diffusion test, and a high level of resistance to penicillin and ampicillin were detected. The most efficient antibiotics evaluated were gentamicin, vancomicin and the association ampicillin+sulbactam. Oxacillin resistance was phenotypically detected by modified disc diffusion test, agar screen, broth microdilution and agar dilution. Presence of mecA gene where detected in 5,55% of the isolates by Polimerase Chain Reaction (PCR). Correlation with the detection of mecA gene was used as gold standard for evaluation of sensitivity and specificity of phenotypical assays. The low number of mecA positives isolates did not allowed the association between cefoxitin and oxacillin resistance as a test to detect the presence this gene. The broth microdilution and agar dilution tests presented the best accuracy in phenotypic detection of the oxacillin resistance. / Os estafilococos coagulasenegativos (ECN) fazem parte da microbiota normal da pele e apesar de terem sido considerados sapr?fitas por muito tempo, o seu significado cl?nico como agente etiol?gico tem aumentado com o passar dos anos. No entanto, apesar de todo avan?o nas t?cnicas de identifica??o dos ECN e do conhecimento destes como agentes etiol?gicos em diversos processos infecciosos, estes microrganismos muitas vezes s?o negligenciados na rotina laboratorial, devido a enorme diversidade de esp?cies encontradas. A identifica??o das esp?cies de ECN, embora de dif?cil realiza??o para a maioria dos laborat?rios cl?nicos, ? necess?ria para diferenciar o potencial patog?nico e o perfil de resist?ncia de cada isolado. A resist?ncia ? oxacilina em ECN ? mediada pelo gene mecA e usualmente heterog?nea, sendo detectada por v?rios m?todos fenot?picos. Neste estudo, foram avaliados 72 isolados de ECN provenientes de amostras do conduto auditivo de c?es da ra?a Beagles, de mastite bovina e de infec??es humanas. Staphylococcus xylosus foi o microrganismo mais isolado, nas amostras animais, e S. cohnii subsp.urealyticus em humanos, dentro de uma ampla gama de esp?cies identificadas. O perfil de resist?ncia aos antimicrobianos em isolados de animais e humanas foi avaliado atrav?s da t?cnica de difus?o em disco, na qual detectouse um elevado n?vel de resist?ncia ? penicilina e ampicilina. A gentamicina, vancomicina e associa??o ampicilina+sulbactam foram eficientes frente aos isolados testados. A avalia??o da resist?ncia ? oxacilina foi realizada atrav?s da difus?o em disco modificada, ?gar screen, microdilui??o em caldo e em ?gar. A presen?a do gene mecA foi determinada pelo m?todo da Rea??o em Cadeia de Polimerase (PCR), sendo 5,55% dos isolados mecA positivos. Os resultados fenot?picos de resist?ncia a cefoxitina e a oxacilina foram correlacionados com a detec??o do gene mecA, que foi utilizado como padr?o ouro para avalia??o da sensibilidade e especificidade das t?cnicas utilizadas. O reduzido n?mero de isolados mecA + n?o permitiu estabelecer o grau de correla??o entre a cefoxitina e a oxacilina como m?todo de predi??o do gene, embora ambas tenha apresentado o mesmo percentual de resist?ncia. O teste fenot?pico que apresentou melhor acur?cia na detec??o da resist?ncia ? oxacilina foi a microdilui??o em caldo.

Σκοπός της παρούσας ερευνητικής εργασίας ήταν η επιδημιολογική μελέτη των σταφυλοκοκκικών λοιμώξεων από πηκτάση–αρνητικούς σταφυλοκόκκους (CNS) σε ασθενείς της Μονάδας Εντατικής Θεραπείας των πρόωρων νεογνών του Πανεπιστημιακoύ Γενικού Νοσοκομείου Πατρών (ΠΓΝΠ) μεταξύ 2002-2004. Κατά τη διάρκεια της μελέτης, συλλέχθηκαν συνολικά 287 στελέχη CNS. Τα στελέχη ελέγχθηκαν για την παραγωγή της πρωτεΐνης PBP2α και την ύπαρξη του γονιδίου mecA για τον προσδιορισμό των ανθεκτικών στη methicillin στελεχών CNS. Από το σύνολο των 287 CNS, τα 132 (46%) χαρακτηρίσθηκαν ως MRCNS. Τα MRCNS αποτελούν σοβαρό πρόβλημα για τα νοσοκομεία, γιατί αυξάνουν τον χρόνο παραμονής των ασθενών στο νοσοκομείο, άρα και το κόστος νοσηλείας και θεραπείας. Έγινε μελέτη του φαινοτύπου αντοχής των στελεχών σε αντιβιοτικά, της κλωνικής τους διασποράς και της ικανότητάς παραγωγής βιομεμβράνης σε σύγκριση με την παρουσία των γονιδίων του οπερονίου ica. Για την επιδημιολογική μελέτη των λοιμώξεων που οφείλονται σε MRCNS, μέθοδος αναφοράς είναι η PFGE, κυρίως σε συνδυασμό και με υβριδισμό του χρωμοσωμικού DNA με ειδικούς ανιχνευτές. Όλα τα στελέχη MRCNS ήταν πολυανθεκτικά και η πλειονότητά τους παρήγαγε βιομεμβράνη (89%). Μεταξύ των 115 στελεχών S. epidermidis αναδείχθηκε ένας κυριάρχος κλώνος (z) (77 στελέχη) και ακολούθησε ο κλώνος (g). Τα δέκα από τα δεκαέξι στελέχη του είδους S. haemolyticus ανήκαν στον κλώνο (y). Το οπερόνιο ica συμβάλλει στην παραγωγή της εξωκυττάριας ουσίας polysaccharide-intercellular-adhesin (ΡΙΑ) που είναι το κύριο συστατικό του biofilm. Η έκφραση των γονιδίων του οπερονίου ica επάγεται από την παρουσία του ρυθμιστικού γονιδίου sarA, ενώ καταστέλλεται από το γονίδιο icaR. Τα περισσότερα στελέχη που ήταν biofilm-θετικά (80%) έφεραν όλα τα γονίδια του οπερονίου ica και το τρανσποζόνιο IS256, ενώ τα υπόλοιπα 23 είχαν ποικίλους συνδυασμούς των γονιδίων. Η παρουσία όλων των γονιδίων του οπερονίου ica ανιχνεύθηκε σε τρία από τα δεκαπέντε biofilm-αρνητικά στελέχη. Αναδείχθηκαν ένας κύριος και δύο δευτερεύοντες biofilm-θετικοί, πολυανθεκτικοί MRCNS κλώνοι, που αποίκισαν και προξένησαν λοιμώξεις στα πρόωρα νεογνά. Μέρος της παρούσας ερευνητικής εργασίας ήταν η διερεύνηση της επίδρασης του χρόνου επώασης στη γονιδιακή έκφραση σε δεκατέσσερα αντιπροσωπευτικά στελέχη. Αυτό έγινε μέσω της ποσοτικοποίησης με αλυσιδωτή αντίδραση πολυμεράσης πραγματικού χρόνου (RT-PCR) των γονιδίων icaA και icaD τα οποία κυρίως σχετίζονται με την παραγωγή biofilm, καθώς και δύο ρυθμιστικών γονιδίων icaR και sarA σε σύγκριση με ένα συντηρημένο γονίδιο αναφοράς (23S rDNA). Ο έλεγχος έγινε σε στελέχη S. epidermidis που ήταν ανθεκτικά στη methicillin, κατατάσσονταν σε διαφορετικούς κλώνους, εμφάνιζαν διαφορετικό φαινότυπο σύνθεσης βιομεμβράνης και έφεραν ποικίλους συνδυασμούς γονίδιων. Οι αντιδράσεις απόλυτης ποσοτικοποίησης έκφρασης των γονιδίων είχαν υψηλή απόδοση (1,86 και 1,84 για την επώαση στις τέσσερις ώρες και δύο ώρες, αντίστοιχα). Η μαθηματική ανάλυση δεν έδειξε ιδιαίτερα μεγάλες διαφορές μεταξύ των αποτελεσμάτων για τα τέσσερα γονίδια και τους δύο χρόνους επώασης. Αυτό που παρατηρήθηκε ήταν οτι η έκφραση ήταν υψηλότερη στα biofilm-θετικά στελέχη. Προκειμένου να μελετηθεί η επίδραση της βακτηριακής προσκόλλησης στις διάφορες επιφάνειες τροποποιημένου και μη τροποποιημένου γυαλιού, πραγματοποιήθηκαν δυναμικά πειράματα, κάτω από δύο διαφορετικές συνθήκες ροής, σε δύο χρόνους επώασης σε τέσσερα στελέχη S. epidermidis. Η βακτηριακή προσκόλληση, η παραγωγή biofilm και ο σχηματισμός βιομεμβράνης στις τροποποιημένες επιφάνειες ήταν αυξημένα σε σχέση με τις μη τροποποιημένες. Αυτό ήταν σε συμφωνία με τα αποτελέσματα της γονιδιακής έκφρασης των γονιδίων icaA και icaD, μετά από ανάλυση της έκφρασης των γονιδίων icaA και icaD με RT-PCR, που έδειξε αυξημένες τιμές στις τροποποιημένες επιφάνειες, κυρίως στην υψηλή ροή. Επομένως, ο συνδυασμός της δράσης της χημείας της επιφάνειας και της ροής, επηρεάζουν την προσκόλληση, τον φαινότυπο και το γονότυπο των βακτηριακών στελεχών, όπως και την προσαρμογή τους στις αλλαγές του περιβάλλοντος. Η μελέτη της γονιδιακής έκφρασης μπορεί να βοηθήσει στην κατανόηση των αλληλεπιδράσεων της βακτηριακής προσκόλλησης με το βιοϋλικό. / A total of 132 methicillin-resistant coagulase-negative staphylococci (MRCNS) isolated from preterm neonates were studied for antibiotic resistance patterns, clonal distribution and biofilm formation in relation to the presence of ica operon. All MR-CNS were multi-resistant while the majority (89%) produced biofilm. Among 115 Staphylococcus epidermidis, a major clone (z) was identified (77 strains), followed by clone g. Ten out of 16 S. haemolyticus belonged to a common clone (y). Most of the biofilm-positive strains (80%) possessed all tested genes, while the remaining 23 had a variety of gene combinations. Presence of the entire ica cluster was detected in three out of 15 biofilm-negative strains. One major and two minor biofilm-positive, multi-resistant MRCNS clones were disseminated, colonizing and infecting hospitalized preterm neonates. Fourteen representative MR- S. epidermidis strains were selected and investigated for the expression of icaA and icaD genes, and two regulatory genes, icaR (repressor) and sarA (inducer), towards a housekeeping gene (23SrDNA), by Real-Time PCR (RT-PCR). These strains belonged to various clones, had different combinations of ica genes and biofilm-forming phenotypes. The experiments were performed in two incubation times, after two and four hours. Νο differences were observed at the gene expression level at the two tested times. In general, biofilm-positive strains had higher expression rates for ica operon and sarA genes and lower for the repressor of ica cluster gene (icaR). In order to investigate the interaction of bacteria with the surfaces after attachment, dynamic experiments were performed under two flow conditions. Two different surfaces were used, a modified and a non-modified glass surface. Bacterial adhesion, as well as biofilm production and biofilm formation, was much higher on the modified surface than on the non-modified one for four S. epidermidis strains. This was in agreement with icaA and icaD gene expression that showed increased expression by RT-PCR, for the bacteria adhered at the modified substrate, especially under the high shear rate. Therefore, the combined effect of surface chemistry and shear significantly influence the adhesion of interacting bacterial cells. This indicates that analysis of gene expression not only can greatly refine our knowledge of bacterial-material interactions, but also yield novel biomarkers for potential use in biocompatibility assessment.

Nas últimas décadas, os Staphylococcus coagulase-negativo, têm sido considerados como patógenos verdadeiros, sendo um dos principais grupos bacterianos responsáveis pelas infecções relacionadas a assistência a saúde (IRAS). O presente estudo teve como objetivo geral: avaliação da relação entre a resistência a oxacilina e a produção de biofilme de amostras Staphylococcus coagulase-negativo de origem comunitária e hospitalar. Neste sentido, foram desenvolvidos os seguintes objetivos específico: identificar ao nível de espécie os Staphylococcus coagulase-negativo; analisar por técnica fenotípica (Ágar vermelho do Congo) a produção de slime; avaliar quantitativamente, a produção de biofilme; correlacionar a produção de polissacarídeos extracelulares (slime) com a produção de biofilme; avaliar a relação da resistência a oxacilina como indicador da presença do gene mecA; avaliar a relação entre a concentração inibitória mínima e a concentração bactericida mínima para oxacilina; pesquisar a presença dos genes mecA, icaAD e atlE, pela técnica de PCR. Foi estudado um total de 150 amostras, sendo 50 isoladas de fômites, 50 isoladas de sangue e 50 isoladas de comunidade. Independente da origem, foram identificadas 14 espécies de Staphylococcus coagulase-negativo, sendo mais frequentes S. epidermidis 42,6%, S. haemolyticus 13,3% e S. cohnii cohnii 10,7%. A análise geral da expressão fenotípica de slime mostrou que 64% das amostras avaliadas eram produtoras de slime. Das 150 amostras testadas neste estudo, 95,3% foram produtoras de biofilme. Ao considerarmos a análise da quantificação do biofilme em relação às origens das amostras estudadas não encontramos diferenças significativas e a maioria das amostras foi considerada moderadamente produtora de biofilme. O gene mecA foi detectado em 6 amostras comunitárias, 34 amostras de fômites e 34 amostras de sangue. Não houve diferença significativa entre as amostras de fômites e sangue. Porém, houve diferença significativa entre as amostras de origem comunitária e as de origem hospitalar - fômites e sangue (p < 0,0001). Ao compararmos as três origens de isolamento quanto a presença do gene atlE observamos que houve diferença significativa (p = 0,0012) entre elas. Sendo, as amostras isoladas de sangue, as que apresentaram maior número de amostras que possuíam o gene atlE (n = 18). Das 150 amostras testadas observamos a presença do gene icaAD em 46% amostras comunitárias, 56% amostras de fômites e 60% amostras de sangue, não encontramos diferença significativa (p = 0,5750). Observamos uma correlação entre a resistência a oxacilina e a produção de slime, pois as amostras de origem hospitalar (fômites e sangue) apresentaram altos níveis de resistência a oxacilina e em sua grande maioria foram produtoras de slime. A espécie S. epidermidis foi a mais isolada e deve-se ressaltar que, quando comparada com as outras espécies, apresentou altos níveis de resistência a oxacilina, sendo a maioria produtora de slime e biofilme. / In recent decades, coagulase-negative Stapphylococci have been considered as true pathogen, one of the major bacterial groups responsible for hospital infection. The present study aimed to: assess the relationship between oxacillin resistance and biofilm production samples coagulase-negative Stapphylococci of community and hospital. In this sense, we have developed the following specific objectives: to identify to species level coagulase-negative Staphylococci; analyze by phenotypic test (Congo red Agar) slime production, evaluate quantitatively the biofilm production; correlate the production of extracellular polysaccharides (slime) with biofilm production; evaluate the relationship of resistance to oxacillin as an indicator of the presence of the mecA gene; evaluate the relationship between minimal inhibitory concentration and minimum bactericidal concentration for oxacillin; investigate the presence of the mecA gene, atlE and icaAD, by PCR. We studied a total of 150 samples, 50 were isolated from fomites, 50 from community and 50 isolated from blood. Regardless of origin, 14 species of coagulase-negative Stapphylococci were identified , being more frequent 42.6% S.epidermidis, 13.3% S. haemolyticus and 10.7% S. cohnii cohnii. A general analysis of the phenotypic expression of slime showed that 64% of the samples were slime producers. Of the 150 samples tested in this study, 95.3% produced biofilm. When we consider the analysis of quantification of biofilm in relation to the origins of the samples studied we did not find significant differences and most of the samples were considered moderately biofilm producers. The mecA gene was detected in 6 community samples, 34 samples of fomites and 34 blood samples. There was no significant difference between the samples of blood and fomites. However, there was significant differences between the samples from the community and nosocomial - fomites and blood (p <0.0001). Comparing the three origins insulation as the presence of the gene atlE we observed a significant difference (p = 0.0012) between them. Being the isolated blood samples which showed the highest number of samples that had the gene atlE (n = 18). From the 150 tested samples we observed the presence of the gene icaAD 46% in community samples, 56% samples from fomites and 60% of blood samples, we found no significant difference (p = 0.5750). We observed a correlation between oxacillin resistance and slime production, because the nosocomial (fomites and blood) samples showed high levels of resistance to oxacillin and mostly were slime producers. The species S. epidermidis were the most isolated and it should be noted that, compared with other species, it showed high levels of resistance to oxacillin, mostly producing slime and biofilm.

Made available in DSpace on 2014-06-11T19:23:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-26Bitstream added on 2014-06-13T19:28:47Z : No. of bitstreams: 1 oliveira_a_me_botib.pdf: 2150093 bytes, checksum: 919f378505685748f61cc9d4768d368e (MD5) / Os estafilococos coagulase-negativa (ECN) estão entre os microrganismos mais envolvidos em infecções nosocomiais, principalmente em recém-nascidos (RN) prematuros e de baixo peso. Entre os fatores de risco para infecções por esses agentes, a produção de um polissacarídeo extracelular e a conseqüente formação do biofilme, permitindo aderência às superfícies plásticas e lisas de cateteres e outros dispositivos médicos desempenham um papel importante. Uma coleção de 100 amostras de ECN, sendo 50 isoladas de pontas de cateteres e 30 de hemoculturas obtidas de RN da Unidade Neonatal do Hospital das Clínicas da Faculdade de Medicina de Botucatu, UNESP e 20 obtidas de fossas nasais de portadores saudáveis foi analisada quanto à produção de biofilme pelos métodos do tubo (TM), ágar vermelho congo (CRA) e através do método quantitativo de aderência a placa de poliestireno (TCP). Esses métodos foram comparados com a pesquisa dos genes icaA, icaD e icaC envolvidos na produção de biofilme em ECN. Das 100 amostras de ECN estudadas, 82% foram positivas pela técnica de PCR, 82% pelo método do tubo, 81% pelo método da placa de poliestireno e 76% pelo CRA. O método de aderência ao tubo (TM) foi o teste que mostrou resultados mais confiáveis, com uma sensibilidade e especificidade de 100% e boa concordância quando comparado a técnica de PCR. Com o objetivo de determinar o papel do biofilme como fator de risco na ocorrência de infecções em RN, 130 amostras de estafilococos coagulasenegativa (ECN) isoladas de recém-nascidos (RN) internados na Unidade Neonatal do Hospital das Clínicas da Faculdade de Medicina de Botucatu foram identificadas e classificadas em significativas e contaminantes, baseado em dados clínicos e laboratoriais obtidos dos prontuários dos RN. Foram pesquisados fatores perinatais de risco para infecção, evolução clínica dos RN e antibiotico... / Coagulase-negative staphylococci (CNS) are most often associated with nosocomial infections, especially in premature and under weight newborns. The most important pathogenic factor of these microorganisms is the production of extracellular polysaccharide and the consequent formation of biofilm which facilitates their adherence to the surfaces of catheters and other medical devices. A total of 100 clinical isolates of coagulase-negative staphylococci (CNS) isolated from infected medical devices received from the Neonatal Unit, University Hospital, Botucatu Medical Schooll, including 50 isolated from catheter tips, 30 from blood cultures, and 20 collected from the nasal cavity of healthy subjects were investigated in order to evaluate the efficiency of three phenotypic methods of detection of biofilm formation, and also analyze the icaA, icaD and icaC genes, using the PCR method. The clinical isolates were screened by tissue culture plate (TCP), Tube method (TM), and Congo Red Agar (CRA) method. Of the 100 tested isolates, 82% were positive in the PCR method; in the TM, 82%; in the TCP assay, 81%; and 76% in CRA method. The method of adherence to the test tube was shown that more reliable results, with a sensitivity and specificity of 100% and good agreement when compared with the PCR technique. In order to determine the role of biofilm as a risk factor in the occurrence of infections in newborns 130 clinical isolates of CNS were identified and classified as significant and contaminant, based on clinical data obtained from the patients’ reports. Perinatal risk factors for infection, clinical evolution and antibiotic therapy for the newborns were studied, as well as the detection of the genes responsible for the production of biofilm in CNS.Of the 130 clinical isolates of CNS, 66 (50.8%) were classified as clinically significant and 64 (49.2%) as contaminant... (Complete abstract click electronic access below)

Nas últimas décadas, os Staphylococcus coagulase-negativo, têm sido considerados como patógenos verdadeiros, sendo um dos principais grupos bacterianos responsáveis pelas infecções relacionadas a assistência a saúde (IRAS). O presente estudo teve como objetivo geral: avaliação da relação entre a resistência a oxacilina e a produção de biofilme de amostras Staphylococcus coagulase-negativo de origem comunitária e hospitalar. Neste sentido, foram desenvolvidos os seguintes objetivos específico: identificar ao nível de espécie os Staphylococcus coagulase-negativo; analisar por técnica fenotípica (Ágar vermelho do Congo) a produção de slime; avaliar quantitativamente, a produção de biofilme; correlacionar a produção de polissacarídeos extracelulares (slime) com a produção de biofilme; avaliar a relação da resistência a oxacilina como indicador da presença do gene mecA; avaliar a relação entre a concentração inibitória mínima e a concentração bactericida mínima para oxacilina; pesquisar a presença dos genes mecA, icaAD e atlE, pela técnica de PCR. Foi estudado um total de 150 amostras, sendo 50 isoladas de fômites, 50 isoladas de sangue e 50 isoladas de comunidade. Independente da origem, foram identificadas 14 espécies de Staphylococcus coagulase-negativo, sendo mais frequentes S. epidermidis 42,6%, S. haemolyticus 13,3% e S. cohnii cohnii 10,7%. A análise geral da expressão fenotípica de slime mostrou que 64% das amostras avaliadas eram produtoras de slime. Das 150 amostras testadas neste estudo, 95,3% foram produtoras de biofilme. Ao considerarmos a análise da quantificação do biofilme em relação às origens das amostras estudadas não encontramos diferenças significativas e a maioria das amostras foi considerada moderadamente produtora de biofilme. O gene mecA foi detectado em 6 amostras comunitárias, 34 amostras de fômites e 34 amostras de sangue. Não houve diferença significativa entre as amostras de fômites e sangue. Porém, houve diferença significativa entre as amostras de origem comunitária e as de origem hospitalar - fômites e sangue (p < 0,0001). Ao compararmos as três origens de isolamento quanto a presença do gene atlE observamos que houve diferença significativa (p = 0,0012) entre elas. Sendo, as amostras isoladas de sangue, as que apresentaram maior número de amostras que possuíam o gene atlE (n = 18). Das 150 amostras testadas observamos a presença do gene icaAD em 46% amostras comunitárias, 56% amostras de fômites e 60% amostras de sangue, não encontramos diferença significativa (p = 0,5750). Observamos uma correlação entre a resistência a oxacilina e a produção de slime, pois as amostras de origem hospitalar (fômites e sangue) apresentaram altos níveis de resistência a oxacilina e em sua grande maioria foram produtoras de slime. A espécie S. epidermidis foi a mais isolada e deve-se ressaltar que, quando comparada com as outras espécies, apresentou altos níveis de resistência a oxacilina, sendo a maioria produtora de slime e biofilme. / In recent decades, coagulase-negative Stapphylococci have been considered as true pathogen, one of the major bacterial groups responsible for hospital infection. The present study aimed to: assess the relationship between oxacillin resistance and biofilm production samples coagulase-negative Stapphylococci of community and hospital. In this sense, we have developed the following specific objectives: to identify to species level coagulase-negative Staphylococci; analyze by phenotypic test (Congo red Agar) slime production, evaluate quantitatively the biofilm production; correlate the production of extracellular polysaccharides (slime) with biofilm production; evaluate the relationship of resistance to oxacillin as an indicator of the presence of the mecA gene; evaluate the relationship between minimal inhibitory concentration and minimum bactericidal concentration for oxacillin; investigate the presence of the mecA gene, atlE and icaAD, by PCR. We studied a total of 150 samples, 50 were isolated from fomites, 50 from community and 50 isolated from blood. Regardless of origin, 14 species of coagulase-negative Stapphylococci were identified , being more frequent 42.6% S.epidermidis, 13.3% S. haemolyticus and 10.7% S. cohnii cohnii. A general analysis of the phenotypic expression of slime showed that 64% of the samples were slime producers. Of the 150 samples tested in this study, 95.3% produced biofilm. When we consider the analysis of quantification of biofilm in relation to the origins of the samples studied we did not find significant differences and most of the samples were considered moderately biofilm producers. The mecA gene was detected in 6 community samples, 34 samples of fomites and 34 blood samples. There was no significant difference between the samples of blood and fomites. However, there was significant differences between the samples from the community and nosocomial - fomites and blood (p <0.0001). Comparing the three origins insulation as the presence of the gene atlE we observed a significant difference (p = 0.0012) between them. Being the isolated blood samples which showed the highest number of samples that had the gene atlE (n = 18). From the 150 tested samples we observed the presence of the gene icaAD 46% in community samples, 56% samples from fomites and 60% of blood samples, we found no significant difference (p = 0.5750). We observed a correlation between oxacillin resistance and slime production, because the nosocomial (fomites and blood) samples showed high levels of resistance to oxacillin and mostly were slime producers. The species S. epidermidis were the most isolated and it should be noted that, compared with other species, it showed high levels of resistance to oxacillin, mostly producing slime and biofilm.

Coagulase negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet concentrates (PCs), and have been implicated in severe and fatal transfusion reactions. Of this group, Staphylococcus epidermidis is most frequently identified. The preliminary objective of this thesis was to confirm that S. epidermidis could form biofilms under platelet storage conditions. This was achieved using a modified crystal violet staining assay to detect plastic-adherent bacterial cells and examination of attachment processes by scanning electron microscopy. A collection of CoNS isolated from PCs obtained from reportedly healthy donors was then assessed for biofilm-forming potential at the genetic and phenotypic level. Despite the presumable commensal origin of these isolates, a high proportion of S. epidermidis strains displayed a biofilm positive phenotype. The threat of S. epidermidis biofilm formation during platelet storage identified herein signifies that any alterations made to platelet storage protocols should be evaluated with consideration of this risk. The advent of platelet additive solutions (PASs) as an alternative to plasma for PC storage provides a relevant example, since little is known about the effect of PAS on contaminant bacteria, and vice versa. Growth and biofilm formation by S. epidermidis and the Gram-negative bacterium Serratia liquefaciens were measured in PAS- or plasma-PCs over 5 days, simulating standard platelet storage conditions, after initial inoculation with low, clinically relevant bacterial concentrations. Assays for platelet quality were performed simultaneously. Only S. liquefaciens exhibited a slower doubling time in plasma-PCs than in PAS-PCs. Biofilm formation by both species was reduced during storage in PAS-PCs, increasing bacteria availability for detection. Although S. liquefaciens adversely affected platelet quality in both media, S. epidermidis contamination did not. Ultimately, culture-based detection remains the earliest indicator of bacterial presence in PAS-PCs. Lastly, since formation of platelet-bacteria aggregates is largely based on receptor-ligand interactions, it was postulated that biofilm formation by contaminant bacteria could be abrogated by receptor shielding. Methoxypoly(ethylene glycol) was applied to covalently modify the platelet surface using a process termed ‘PEGylation’. It is herein demonstrated that PEGylation of PCs inoculated with S. epidermidis results in significantly reduced bacterial binding and biofilm formation during platelet storage.

Coagulase negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet concentrates (PCs), and have been implicated in severe and fatal transfusion reactions. Of this group, Staphylococcus epidermidis is most frequently identified. The preliminary objective of this thesis was to confirm that S. epidermidis could form biofilms under platelet storage conditions. This was achieved using a modified crystal violet staining assay to detect plastic-adherent bacterial cells and examination of attachment processes by scanning electron microscopy. A collection of CoNS isolated from PCs obtained from reportedly healthy donors was then assessed for biofilm-forming potential at the genetic and phenotypic level. Despite the presumable commensal origin of these isolates, a high proportion of S. epidermidis strains displayed a biofilm positive phenotype. The threat of S. epidermidis biofilm formation during platelet storage identified herein signifies that any alterations made to platelet storage protocols should be evaluated with consideration of this risk. The advent of platelet additive solutions (PASs) as an alternative to plasma for PC storage provides a relevant example, since little is known about the effect of PAS on contaminant bacteria, and vice versa. Growth and biofilm formation by S. epidermidis and the Gram-negative bacterium Serratia liquefaciens were measured in PAS- or plasma-PCs over 5 days, simulating standard platelet storage conditions, after initial inoculation with low, clinically relevant bacterial concentrations. Assays for platelet quality were performed simultaneously. Only S. liquefaciens exhibited a slower doubling time in plasma-PCs than in PAS-PCs. Biofilm formation by both species was reduced during storage in PAS-PCs, increasing bacteria availability for detection. Although S. liquefaciens adversely affected platelet quality in both media, S. epidermidis contamination did not. Ultimately, culture-based detection remains the earliest indicator of bacterial presence in PAS-PCs. Lastly, since formation of platelet-bacteria aggregates is largely based on receptor-ligand interactions, it was postulated that biofilm formation by contaminant bacteria could be abrogated by receptor shielding. Methoxypoly(ethylene glycol) was applied to covalently modify the platelet surface using a process termed ‘PEGylation’. It is herein demonstrated that PEGylation of PCs inoculated with S. epidermidis results in significantly reduced bacterial binding and biofilm formation during platelet storage.

Σκοπός της παρούσας ερευνητικής εργασίας ήταν η επιδημιολογική μελέτη των λοιμώξεων από πηκτάση-αρνητικούς σταφυλοκόκκους (CNS) σε ασθενείς με προσθετικά υλικά, όπως ενδαγγειακούς καθετήρες και η σύγκριση με στελέχη που προκαλούν βακτηριαιμία. Συνολικά μελετήθηκαν 168 Staphylococcus epidermidis και 58 S. haemolyticus από βακτηριαιμίες (BSIs, 100 στελέχη) και εντοπισμένες λοιμώξεις σχετιζόμενες με την εφαρμογή προσθετικών υλικών (PDAIs, 126 στελέχη) από ασθενείς του Πανεπιστημιακού Γενικού Νοσοκομείου Πατρών (ΠΓΝΠ) και του Νοσοκομείου Παίδων Πεντέλης (ΝΠΠ). Η πλειοψηφία των στελεχών (89.8%) ήταν ανθεκτικά στην methicillin (MR-CNS) και πολυανθεκτικά (90.7%). Βιομεμβράνη συνέθεταν τα 106/226 στελέχη, ενώ 208 παρήγαγαν β-λακταμάση. Τα γονίδια σύνθεσης προσκολλητινών aap, fnbA και bap βρέθηκαν σε συχνότητα 40.3%, 35.8% και 20.4% αντίστοιχα. Οι S. epidermidis έφεραν τα γονίδια atlE και fbe σε ποσοστά 88.1% και 81%, αντίστοιχα. Από τα γονίδια σύνθεσης τοξινών, συχνότερο ήταν το γονίδιο της τοξίνης τοξικής καταπληξίας tst (8.4%) ενώ τα γονίδια που κωδικοποιούν τις εντεροτοξίνες sea, sec βρέθηκαν μόνο σε μικρό ποσοστό στελεχών S. epidermidis και S. haemolyticus (5.3% και 3.1% του συνολικού πληθυσμού αντίστοιχα). Κανένα στέλεχος δεν έφερε τα γονίδια σύνθεσης των εντεροτοξινών seb και sed. Ο πληθυσμός των στελεχών S. epidermidis έδειξε μεγάλη γενετική ποικιλομορφία, με 67 PFGE τύπους, μεταξύ των οποίων δύο κύριοι τύποι (a, b) με 50 και 36 στελέχη αντίστοιχα. Έλεγχος με MLST ανέδειξε τρεις κύριους κλώνους (ST2, ST5 και ST16) που ανήκαν στο ίδιο κλωνικό σύμπλεγμα (Clonal Complex 2). Τα στελέχη του PFGE τύπου a παρουσίασαν υψηλότερα ποσοστά αντοχής στα αντιμικροβιακά clindamycin, ciprofloxacin, fusidic acid, SXT και στις αμινογλυκοσίδες, ενώ τα στελέχη του τύπου b έφεραν συχνότερα το γονίδιο aap (p=0.049). Τα στελέχη S. haemolyticus παρουσίασαν μικρότερη γενετική ποικιλομορφία, με έναν κύριο PFGE τύπο (h), που περιελάμβανε 44/58 στελέχη (75.9% του συνολικού πληθυσμού). Τα στελέχη CNS από BSIs ήταν συχνότερα ανθεκτικά στην methicillin (p<0.001) και στα υπόλοιπα αντιμικροβιακά (p<0.05), ενώ υπερείχαν και στην παραγωγή biofilm (p=0.003). Αντιθέτως, οι CNS από PDAIs έφεραν συχνότερα τα γονίδια των προσκολλητινών aap (p=0.006) και bap (p=0.045). Σε ένα δεύτερο σκέλος της παρούσας ερευνητικής εργασίας μελετήθηκε ένας πληθυσμός S. lugdunensis από το ΠΓΝΠ (37 στελέχη) και το ΝΠΠ (1 στέλεχος). Ο S. lugdunensis κατέχει ιδιαίτερη θέση μεταξύ των CNS, καθώς μπορεί να μιμηθεί την παθογόνο δράση του S. aureus και να προκαλέσει σοβαρές λοιμώξεις. Είκοσι δύο S. lugdunensis απομονώθηκαν από ασθενείς με λοιμώξεις δέρματος και μαλακών μορίων (Skin and Soft Tissue Infections: SSTIs), εννέα από εν τω βάθει λοιμώξεις (Deep Sited Infections: DSIs), συμπεριλαμβανομένων τριών στελεχών από ασθενείς με βακτηριαιμία, και επτά στελέχη από λοιμώξεις σχετιζόμενες με προσθετικά υλικά, κυρίως ενδαγγειακούς καθετήρες, (PDAIs). Όλα τα στελέχη ήταν ευαίσθητα στην methicillin (MS-CNS), στις αμινογλυκοσίδες (kanamycin, gentamicin), καθώς και στα: ciprofloxacin, rifampicin, teicoplanin, vancomycin, linezolid και daptomycin, ενώ μόνο τέσσερα στελέχη ήταν πολυανθεκτικά. Οι S. lugdunensis της συλλογής μας έδειξαν μικρή γενετική ποικιλομορφία. Τα 38 στελέχη ταξινομήθηκαν σε επτά κλώνους, με δύο κύριους PFGE τύπους (C και D), οι οποίοι περιελάμβαναν 22 και εννέα στελέχη αντίστοιχα. Τα 26 από τα 38 στελέχη έφεραν το οπερόνιο ica, ενώ συνολικά 14 ήταν biofilm-θετικά. Δεν παρατηρήθηκε συσχέτιση της παρουσίας του ica με κάποιο κλώνο, αλλά ούτε και με την παραγωγή βιομεμβράνης. Οι S. lugdunensis από PDAIs ήταν συχνότερα biofilm-θετικοί σε σχέση με τα στελέχη από SSTIs και DSIs, ενώ ο κύριος κλώνος C παρήγαγε biofilm σε μεγαλύτερο ποσοστό από τον D, δεύτερο σε συχνότητα κλώνο. Το γονίδιο fbl ανιχνεύθηκε σε όλα τα στελέχη S. lugdunensis που εξετάστηκαν, επιβεβαιώνοντας την φαινοτυπική ταυτοποίηση σε επίπεδο είδους. Ο επόμενος κατά σειρά συχνότητας παράγοντας παθογένειας που ανιχνεύθηκε ήταν το γονίδιο atlL, το οποίο βρέθηκε σε 36 από τα 38 στελέχη (94.7%). Ακολουθούν οι παράγοντες vwbl και slush, που βρέθηκαν σε 31 (81.6%) και 15 (39.5%) S. lugdunensis, αντίστοιχα. Τα στελέχη από εν τω βάθει λοιμώξεις (DSIs) έφεραν σε μεγαλύτερο ποσοστό τα γονίδια vwbl και slush σε σχέση με αυτά από PDAIs και SSTIs . Ο κλώνος C υπερείχε στην παρουσία του ermC, ενώ τα στελέχη που ανήκαν στον κλώνο D έφεραν σε μεγαλύτερο ποσοστό τα γονίδια vwbl και slush. / Coagulase-negative staphylococci (CNS), especially Staphylococcus epidermidis and S. haemolyticus, have emerged as opportunistic pathogens in patients with low immune response or indwelling medical devices. In the present study, bloodstream (BSIs) and prosthetic-device associated infections (PDAIs) CNS isolates were compared in terms of biofilm formation, antimicrobial resistance, clonal distribution, adhesin and toxin genes carriage. A collection of 226 CNS (168 S. epidermidis and 58 S. haemolyticus) recovered from BSIs (100) and PDAIs (126) of different patients in the Patras tertiary-care University General Hospital (UGHP) and Pentelis Paediatric Hospital in Athens (PPHA), was tested for biofilm formation, antimicrobial susceptibility, mecA, ica operon, adhesin (aap, bap, fnbA, atlE, fbe) and toxin (tst, sea, seb, sec, sed) genes carriage. All CNS were classified into pulsotypes by PFGE, whereas S. epidermidis strains were assigned to sequence types by MLST. In total, 106 isolates (46.9%) produced biofilm, whereas 150 (66.4%) carried ica operon. Most isolates carried mecA and were multidrug resistant (90.7%). The adhesin encoding genes aap, fnbA and bap were identified in 40.3%, 35.8% and 20.4% of the total population, respectively. Genes encoding AtlE and Fbe were found in 88.1% and 81% of S. epidermidis isolates, respectively. CNS recovered from BSIs prevailed in biofilm formation (P=0.003), resistance to antimicrobials and mecA carriage (P<0.001) as compared to isolates derived from PDAIs. CNS from PDAIs carried more frequently aap and bap genes (P=0.006 and P=0.045, respectively). No statistically significant difference in toxin genes carriage was identified (P>0.05). Even though PFGE showed genetic diversity, especially among S. epidermidis, analysis of representative strains from the main PFGE types by MLST, revealed three major clones (ST2, ST5, ST16). A clonal relationship was found concerning antimicrobial susceptibility, ica and aap gene carriage, reinforcing the aspect of clonal expansion in hospital settings. Pathogenesis of BSIs is associated with biofilm formation and high-level antimicrobial resistance, whereas PDAIs are related to the adhesion capability of CNS. In the second part of this study we analyzed a collection of S. lugdunensis isolates recovered from different inpatients hospitalized in UGHP (37 isolates) and PPHA (one isolate) during a six-year period (2008-2013). S. lugdunensis has emerged as a significant human pathogen with distinct clinical and microbiological characteristics. A collection of 38 S. lugdunensis was tested for biofilm formation, antimicrobial susceptibility, clonal distribution, virulence factors (ica operon, fbl, atlL, vwbl, slush) and antibiotic resistance genes (mecA, ermC) carriage. The majority (22) was isolated from skin and soft tissue infections (SSTIs), nine from deep-sited infections (DSIs), including three bacteraemias and seven from PDAIs. All isolates were oxacillin-susceptible, mecA-negative and fbl-positive. The higher resistance rate was detected for ampicillin (50%), followed by erythromycin and clindamycin (18.4%). Fourteen isolates (36.8%) produced biofilm, 26 carried ica operon, but no relation between ica carriage and biofilm formation was identified. Biofilm formation was more frequent in isolates recovered from PDAIs. Thirty six strains (94.7%) carried atlL, 31 (81.6%) vwbl, whereas, slush was detected in fifteen (39.5%). PFGE revealed low level of genetic diversity: strains were classified into seven pulsotypes, with two major clones C and D including 22 and nine strains, respectively. Type C strains, recovered from all infection sites, prevailed in biofilm formation and ermC carriage, whereas, type D strains, associated with SSTIs and DSIs, carried more frequently vwbl, slush or both genes. Despite susceptibility to antimicrobials, clonal expansion and carriage of virulence factors combined with biofilm-producing ability render this species an important pathogen that should not be ignored.