Academic literature on the topic 'Pseudomysd'

Syphacia (Syphacia) brevicaudata sp. nov. is described from the desert rodents Pseudomys desertor Troughton, 1936 and P. hermannsburgensis (Waite, 1896); Syphacia (Syphacia) pseudomyos sp. nov. is described from P. hermannsburgensis from western Queensland and central Northern Territory, Australia. Syphacia (Syphacia) brevicaudata is distinguished from all other species of Syphacia by having a suite of characters including an oval, dorsally and ventrally constricted cephalic plate, no cervical alae, a relatively short tail and two pairs of post-anal papillae. Syphacia (Syphacia) pseudomyos is distinguished from all other species of Syphacia by having a suite of characters including an oval, dorsally and ventrally constricted cephalic plate, no cervical or lateral alae, one pair of post-anal papillae, a relatively short tail and large eggs. Females of a putative species were distinct due to the lack of a cephalic plate but had other characters consistent with the genus. Two other putative species of Syphacia, females only, also collected from P. hermannsburgensis and having oval dorsally and ventrally constricted cephalic plates, could be distinguished from their congeners by a combination of characters including the presence of cervical alae, Syphacia sp. 2, and a protruding vulva, Syphacia sp. 3. These new species are the first records of oxyurid nematodes from the genus Pseudomys, and from Australian arid-zone rodents.

Abstract We describe two new species of sucking lice in the genus Hoplopleura Enderlein, 1904 (Psocodea: Phthiraptera: Hoplopleuridae) from Australia: Hoplopleura gracilicaudatusa n. sp. from the eastern chestnut mouse Pseudomys gracilicaudatus (Gould) (Rodentia: Muridae), and Hoplopleura nanusa n. sp. from the western chestnut mouse Pseudomys nanus (Gould) (Rodentia: Muridae). Pseudomys Gray is the most speciose genus of rodents endemic to Australia with 24 species; however, only two Pseudomys species have been reported previously to be hosts of sucking lice. The description of the new species in the present study doubles the number of sucking louse species known to parasitize Pseudomys mice and increases the total number of sucking louse species known from endemic Australian rodents from 21 to 23. Pseudomys gracilicaudatus and P. nanus are closely related murines that diverged ~1 MYA with distinct and widely separated extant geographic distributions. The two new Hoplopleura species described in the present study share some morphological characters and likely co-evolved and co-speciated with their chestnut mouse hosts.

Microcomplement fixation was used to assess albumin evolution in the history of the rodents of Australia. The results confirmed a monophyletic grouping consisting of the genera Pseudomys, Mastacomys and Notomys, and showed that the genus Pseudomys is paraphyletic. The genera Conilurus, Leporillus and Mesembriomys also formed a monophyletic group. A significant finding was that Leggadina was distantly related to all Pseudomys species, and indeed may be the earliest offshoot of all Australian rodents other than Rattus. Albumin evolution in the Australian rodents has occurred in a manner far from clock-like. Mastacomys Thomas, 1882 is synonymised with Pseudomys Gray, 1832.

Compared with mainland Australia the diversity of rodents in Tasmania is low. In all, there are five species of native rodent in Tasmania. Three species – the water rat, Hydromys chrysogaster, the long-tailed mouse,Pseudomys higginsi and the swamp rat, Rattus lutreolus – are widely distributed. The broad-toothed rat, Mastacomys fuscus, is restricted to moorlands in western Tasmania, while the New Holland mouse, Pseudomys novaehollandiae, is restricted to coastal heath in north-eastern Tasmania and is listed as Rare under Tasmania’s Threatened Species Protection Act 1995. Only one species, Pseudomys higginsi, is endemic to Tasmania. Rattus lutreolus velutinus and Mastacomys fuscus fuscus are endemic subspecies. In addition to the native rodents, three species of exotic rodents are well established in Tasmania.

Nineteen species of rodents, in two families, have been recorded from Victoria in the modern era. Eighteen are of the family Muridae, represented by 15 native and 3 introduced species. The other species, now extinct in Victoria, was the introduced Sciurus carolinensis. Six of the native species are extinct, one is classified Critically Endangered, one Endangered and four Lower Risk – near threatened. Four of the extinct species were restricted to the semi-arid far north-west; these were Leporillus apicalis, L. conditor, Pseudomys bolami and P. desertor. The two other extinct species, Conilurus albipes and Pseudomys australis, inhabited open forest/woodland, and grassy ecosystems. Extant species include Rattus fuscipes and R. lutreolus, both in the sub-family Murinae; both are widespread and common, particularly in southern Victoria. The remaining seven species are in the sub-family Hydromyinae. Hydromys chrysogaster is widespread in waterbodies throughout the state. Notomys mitchellii and Pseudomys apodemoides occur in dry habitats in the north-west of Victoria; they are uncommon, but most of their habitat is reserved. Mastacomys fuscus, found in higher-rainfall areas of southern and eastern Victoria, from coastal dunes to alpine snowfields, is uncommon. The distribution of Pseudomys fumeus is disjunct, in four widely separated areas. It is classified as Endangered. P. shortridgei is restricted to the Grampians and south-western Victoria, where it may be locally common. The most geographically restricted rodent species in Victoria, Pseudomys novaehollandiae, is Critically Endangered and is the subject of special conservation measures. The most critical threats to rodent populations in Victoria are considered to be (1) the lack of active habitat management for those species that require early seral stages in vegetation, (2) predation by introduced carnivores, and (3) the fragmentation of species into small genetically isolated populations.

The Tasmanian long-tailed mouse (Pseudomys higginsi) is more readily trapped in upland habitats (alpine and montane forest habitats) than in lowland forests in southern Tasmania. Morphometric examination of the relationship between hind-foot length and head-body length, and tail length and head-body length, in eight species of Pseudomys reveals that P. higginsi has both a relatively longer hind foot and tail than other species in the genus, but the significance of this is unclear.

This study examined aspects of behaviour in a captive colony of smoky mice, Pseudomys fumeus, over a two year period. Wherever possible behaviours observed in the captive population are compared to data collected in a study of a wild population in south-eastern New South Wales. This paper provides the first recorded observations of behavior in this species. Both captive and wild populations of P. fumeus display strictly nocturnal circadian activity rhythms. In the captive study, P. fumeus were found to exhibit social interactions similar to some previously studied Pseudomys species. However, in the wild, the species was found to communally nest during the breeding season, behaviour not observed in other Pseudomys from similar habitats. P. fumeus in captivity can have more than two litters in one breeding season which suggests that their reproductive parameters are more flexible than previous studies of wild populations have shown. Field data indicate that post-partum oestrus can occur in this species, and that gestation lasts for approximately 30 days, although these observations are based on a small sample.

Copies of author's previously published articles inserted. Bibliography: p. 199-254. In eutherian mammals, the size of the testes and number of spermatozoa produced and stored in the excurrent ducts vary widely between species, with the hydromyine rodents of Australia exhibiting a greater range of interspecific variation than any other closely related group of species. This study compared the efficiency of germ cell production and sperm storage capacity in the extra-testicular ducts of two arid zone species, the plains rat, Pseudomys australis, and the spinifex hopping mouse, Notomys alexis, that have vast differences in testes size and number of stored spermatozoa. Results are discussed.

This study of the parasite fauna of five Australian rodents (Muridae: Hydromyinae: Conilurini) was undertaken to increase the knowledge of Australian parasite biodiversity. Trapping for Zyzomys argurus (Thomas, 1889), Pseudomys delicatulus (Gould, 1842), P. desertor Troughton, 1932, P. gracilicaudatus (Gould, 1845) and P. hermannsburgensis (Waite, 1896) (Rodentia: Muridae) was carried out at 16 locations in Queensland between 2004 to 2006. A total of 51 rats were captured and examined for parasites. In addition, 119 rats, from collections in the Queensland Museum and the University of Sydney, were examined. Finally, 57 samples of parasites collected from the above hosts and deposited at the Australian National Wildlife Collection (CSIRO) were identified. From these five rodent species, 15 species of ectoparasites and 17 species of endoparasites were recorded. Fifteen new host records and 14 new locality records were found. The ectoparasites comprised four species of Laelaps Koch, 1836 (Parasitiformes: Laelapidae), four species of chiggers (Acariformes: Trombiculidae), two species of fleas (Siphonaptera: Pulicidae, Pygiospyllidae) and two species of ticks (Parasitiformes: Ixodidae). Three new species of lice (Anoplura: Hoplopleuridae) were discovered. The 17 endoparasites, all helminths, comprised fourteen species of nematode and three species of cestode. There were 11 species of oxyurids (Nematoda: Oxyuridae, Heteroxynematidae), including 10 new species of Syphacia, two species of Odilia (Nematoda: Heligmonellidae), and one species of Nippostrongylus (Nematoda: Heligmonellidae). Three species of cestodes (Cestoda: Anoplocephalidae, Taeniidae, Davaineidae) were collected. There were no trematodes or acanthocephalans found in any of the rodents examined. No protistan parasites were found in tissue and blood samples taken from the rodents. The mean species diversity of parasites for each host rodent species was consistently low, with values of Simpson’s Reciprocal Index ranging from 1.00 – 1.53. Possible factors contributing to this low diversity include habitat preferences, dietary ecology and social structure. There was no significant relationship found between host body weight and abundance of ectoparasites, or host body weight and species richness of helminths. The index of discrepancy (D) was used to evaluate the distribution of parasite species across host populations. Most parasites were found to have aggregated distributions within the host populations. The exception to this was two of the four species of laelapid mite, with values <5, indicating that they were common across host populations. The phylogenetic relationships of the Syphacia species occurring in the Australian bioregion were investigated using morphological characters. Relatively low resolution of the trees produced indicated that there may be a high degree of similarity between species. Two main clades were identified- a clade of genera of Syphaciini from Borneo was shown to be basal to the clade of species of Syphacia examined. Within the clade of the genus Syphacia, the new species identified in this study formed a single cluster on trees. There was no evidence, however, for strict coevolution of these worms and their hosts. Overall, the research presented here adds considerable knowledge to the previous paucity of information of the parasites of Australian native rodent species. This was achieved by contributing new host records, locality records and identifying and describing several new species. The relationships between conilurin rodents and their parasites suggests that coevolution plays a large part in the speciation of parasites, and that minimal host switching has occurred in the helminths of the conilurins of northern Australia.

Bacteria commonly use two-component sensors to sense and respond to their environment. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa has one of the largest sets of two-component sensors known in bacteria, which likely contributes to its ability to adapt to diverse environments, including the human host. Several of these sensors such as GacS have been shown to play a role in the regulation of virulence in this pathogen. However, the role of the majority of sensors remains unknown. In this thesis I show that the two-component sensor KinB is required for full P. aeruginosa virulence in the recently characterized model host Danio rerio. I found that KinB regulates several virulence-associated phenotypes in P. aeruginosa including pyocyanin and elastase production and motility. I show that KinB regulates these phenotypes through the global sigma factor AlgU, which plays a critical role in the repression of P. aeruginosa acute virulence factors and through its cognate response regulator, AlgB, albeit in a non-canonical manner. KinB’s primary role in the regulation of acute virulence is to act as a phosphatase to dephosphorylate AlgB.

Tese (doutorado)—Universidade de Brasília, Faculdade de Ciências da Saúde, 2008.
Submitted by wesley oliveira leite (leite.wesley@yahoo.com.br) on 2009-09-08T20:28:44Z No. of bitstreams: 1 Tese_Ieda Maria S Torres.pdf: 1184324 bytes, checksum: 1a8f013e18ff6a2485e7ff6182415423 (MD5)
Approved for entry into archive by Luanna Maia(luanna@bce.unb.br) on 2009-09-09T15:08:10Z (GMT) No. of bitstreams: 1 Tese_Ieda Maria S Torres.pdf: 1184324 bytes, checksum: 1a8f013e18ff6a2485e7ff6182415423 (MD5)
Made available in DSpace on 2009-09-09T15:08:10Z (GMT). No. of bitstreams: 1 Tese_Ieda Maria S Torres.pdf: 1184324 bytes, checksum: 1a8f013e18ff6a2485e7ff6182415423 (MD5) Previous issue date: 2008
Pseudomonas aeruginosa é um microrganismo oportunista e tem a capacidade de responder a uma variedade de mudanças ambientais, apresentando alta resistência intrínseca a numerosos agentes antimicrobianos. Cefalosporinas, especialmente ceftazidima e cefepima são efetivas contra Pseudomonas aeruginosa, contudo sua intensa resistência tem limitado o uso desses antimicrobianos. Uma estratégia utilizada para evitar este problema é encapsular esses antimicrobianos em lipossomas unilamelares. Neste estudo, foi comparada a capacidade inibitória de ceftazidima e cefepima encapsuladas em lipossomas com a dos antibióticos na forma livre, contra a cepa de Pseudomonas aeruginosa ATCC 27853. Foram determinados diâmetro, eficiência de encapsulação, estabilidade dos lipossomas e concentração inibitória mínima (CIM) dos antimicrobianos na forma livre e encapsulada. A concentração bactericida mínima (CBM) da ceftazidima e cefepima livre e encapsuladas em lipossomas unilamelares foram determinadas a 1, 2 ou 4 vezes o CIM. O diâmetro médio dos lipossomas foi de 131,88 nm, com eficiência de encapsulação da cefepima e ceftazidima de 2,29 % e 5,77 %, respectivamente. A CIM da ceftazidima e da cefepima encapsuladas em lipossomas foi 50% inferior àquela do fármaco livre. Ceftazidima e cefepima encapsuladas em lipossomas foram mais eficientes quanto ao efeito bactericida sobre a Pseudomonas aeruginosa, não havendo recuperação microbiana após 24 horas de incubação. Isto demonstra o potencial destes sistemas transportadores de fármacos para contribuir na redução do aparecimento de resistência bacteriana a estes antibióticos. ______________________________________________________________________________________ ABSTRACT
Pseudomonas aeruginosa is an opportunistc microorganismi which is able to respond to a large variety of environmental changes exhibits intrinsic resistance to several aintimocrobial agents. Cephalosporins, particularly ceftazidime and cefepime are effective against Pseudomonas aeruginosa, however, its increasing resistance has limites the usage of these antibiotics. Encapsulating antimicrobial drugs into unilamellar liposomes is an approach that has been investigated in order to overcome microorganism resistance. In this study, antimicrobial activity of liposomal ceftazidime and cefepime against Pseudomonas aeruginosa ATCC 27853 was investigated and compared to that of the free drugs. Liposomal characterization included diameter, encapsulations efficiency and stability. Minimal inhibitory concentration (MIC) was determined for free and liposomal forms of both drugs. Minimal bactericidal concentration (MBC) was determined at concentrations 1,2 and 4 times the MIC. Liposome average diameter was 131.88 nm and encapsulation efficiency for cefepime and ceftazidime were 2,29% and 5,77%, respectively. Mic for liposomal antibiotics was 50% lower than that for the free drugs. Liposomal Ceftazidime and cefepime exhibited a more efficient bactericidal effect over Pseudominas aeruginosa, with no microbial regrowth whithin 24 hours of incubation. This demonstrates the ability of these drug delivery sistems in contributing for the reduction of the development of bacterial resistance.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Infections caused by Acinetobacter baumannii and Pseudomonas aeruginosa multiresistant are responsible for high morbidity and mortality, failure of drug therapy, increased hospital stay and consequently the financial impact on the health system. However, while the occurrence of these bacteria to configure a public health problem, numerous studies reveal that it is scarce information about the resistance genes present in multi-drug resistant bacteria. This reality associated with the negative impact of these on society, justifies the importance of detecting the resistance genes of A. baumannii and P. aeruginosa multiresistant and clinically characterize patients from a public hospital in Sergipe. It is an analytical prospective cohort study and a quantitative approach. The collection of clinical data of patients was carried out through a specifically designed form. Strains of A. baumannii were subjected to PCR for identification of resistance genes (blaIMP, blaVIM, blaSIM, bla OXA-51, blaOXA-58, blaOXA-23 and blaOXA-24) and P. aeruginosa the blaSPM genes, blaVIM, blaIMP, blaKPC. Descriptive analyzes were performed, the Chi-square and Fisher exact tests, with 5% significance level. The software used was R version 3.1.2. The sample consisted of 119 patients. Of the 43 patients with P. aeruginosa isolates, 33 were male (76.7%) with mean age of 46.2 years. Twenty-eight were admitted to the ICU (65.1%) and 13 (30.2%) diagnosed with head trauma (TBI). Of the 76 patients with isolates of A. baumannii, 59 (77.6%) were male, mean age of 44.4 years. Fifty patients (65.8%) were from the ICU and 18 (23.7%) diagnosed with TBI. The median number of days of hospitalization was statistically significant between bacteria. Among the isolation sites, there is urine to P. aeruginosa, with 16 samples (37.2%) and tracheal aspirate for A. baumannii with 32 (42.1%) strains. A urinary catheter was the most used device in patients with isolates of A. baumannii (93.4% - 71) and the central venous catheter in patients with P. aeruginosa (93% - 40). All patients with P. aeruginosa isolates made use of carbapenems and 98.6% (75) of A. baumannii. It found statistically significant differences between bacteria in the use of aminoglycosides, 3rd generation cephalosporins and tigecycline. In P. aeruginosa was no significant difference in the use of oxacillin and cephalosporins of 1st and 3rd generations and polymyxin in the various sectors of the hospital. All the samples of A. baumannii and P. aeruginosa were susceptible to colistin, ranging between MIC <= 0.5 and 2. The majority (55.8% - 24) patients with P. aeruginosa and A. baumannii (52.6% - 40) died. Among the 76 strains of A. baumannii, 56 (73.6%) had concomitant both blaOXA-51 and blaOXA-23 genes. Among the 43 strains of P. aeruginosa, 28 (65.1%) had the blaSPM gene. It was concluded that the A.baumannii was more frequent than P. aeruginosa. There was a significant predominance of Pseudomonas and Acinetobacter in the urine in tracheal aspirates. Carbapenems was widely used throughout the hospital stay of patients with Acinetobacter and Pseudomonas isolates in different hospital departments. Most Pseudomonas strains showed blaSPM resistance gene and Acinetobacter blaOXA-23 genes and blaOXA-51 concurrently. The mortality of patients with Acinetobacter and Pseudomonas was greater than 50%.
As infecções causadas por Acinetobacter baumannii e Pseudomonas aeruginosa multirresistentes são responsáveis pela alta morbidade e mortalidade, falência da terapia medicamentosa, aumento do período de internação e consequentemente impacto financeiro no sistema de saúde. Todavia, embora a ocorrência destas bactérias se configure um problema de saúde pública, inúmeros estudos revelam que é escasso o conhecimento acerca dos genes de resistência presentes nas bactérias multirresistentes. Essa realidade associada ao impacto negativo destas na sociedade, justifica a importância de detectar os genes de resistência de A. baumannii e P. aeruginosa multirresistentes e caracterizar clinicamente os pacientes de um hospital público de Sergipe. Trata-se de um estudo analítico de coorte prospectiva e abordagem quantitativa. A coleta dos dados clínicos dos pacientes foi realizada através de um formulário especificamente elaborado. As cepas de A. baumannii foram submetidas à técnica PCR para identificação dos genes de resistência (blaIMP, blaVIM, blaSIM, bla OXA-51, blaOXA-58, blaOXA-23 e blaOXA-24) e em P. aeruginosa os genes blaSPM, blaVIM, blaIMP, blaKPC. Foram realizadas análises descritivas, os testes de Qui-Quadrado e Exato de Fisher, com nível de significância de 5%. O software utilizado foi o R versão 3.1.2. A amostra foi constituída de 119 pacientes. Dos 43 pacientes com isolados de P.aeruginosa, 33 eram do sexo masculino (76,7%), com idade média de 46,2 anos. Vinte e oito estavam internados na UTI (65,1%) e 13 (30,2%) com diagnóstico de trauma crânio encefálico (TCE). Dos 76 pacientes com isolados de A. baumannii, 59 (77,6%) era do sexo masculino, média de idade de 44,4 anos. Cinquenta pacientes (65,8%) eram procedentes da UTI e 18 (23,7%) com diagnóstico de TCE. A mediana de dias de internamento foi estatisticamente significante entre as bactérias. Dentre os sítios de isolamento, destaca-se a urina para P. aeruginosa, com 16 amostras (37,2%) e o aspirado traqueal para A. baumannii com 32 (42,1%) cepas. A sonda vesical foi o dispositivo mais usado nos pacientes com isolados de A. baumannii (93,4% - 71) e o cateter venoso central nos pacientes com P. aeruginosa (93% - 40). Todos os pacientes com isolados de P.aeruginosa fizeram uso dos carbapenêmicos e 98,6% (75) dos A. baumannii. Foi encontrado diferença estatisticamente significante entre as bactérias quanto ao uso dos aminoglicosídeos, cefalosporinas de 3ª geração e tigeciclina. Em P. aeruginosa houve diferença significativa no uso da oxacilina e cefalosporinas de 1ª e 3ª gerações e polimixina nos diversos setores do hospital. Todos as amostras de A. baumannii e P. aeruginosa apresentaram sensibilidade à colistina, com variação da MIC entre < = 0,5 e 2. A maioria (55,8% - 24) dos pacientes com P. aeruginosa e A. baumannii (52,6% - 40) foram a óbito. Dentre as 76 cepas de A. baumannii, 56 (73,6%) apresentaram concomitantemente os dois genes blaOXA-51 e blaOXA-23. Dentre as 43 cepas de P. aeruginosa, 28 (65,1%) apresentaram o gene blaSPM. Concluiu-se que o A.baumannii foi mais frequente do que a P.aeruginosa. Houve predomínio significante da Pseudomonas na urina e do Acinetobacter na secreção traqueal. Os carbapenêmicos foi amplamente utilizado ao longo da internação dos pacientes com isolados de Acinetobacter e Pseudomonas nos diversos setores do hospital. A maioria das cepas de Pseudomonas apresentaram gene de resistência blaSPM e Acinetobacter os genes blaOXA-23 e blaOXA-51 concomitantemente. A mortalidade dos pacientes com Acinetobacter e Pseudomonas foi superior a 50%.

Introducción. Pseudomonas aeruginosa es bacilo gramnegativo no-fermentador responsable de una proporción elevada de las infecciones adquiridas en hospitales, en particular en las unidades de cuidados intensivos (UCI). Las infecciones por P. aeruginosa a menudo son graves y difíciles de tratar debido a que tienen un alto nivel de resistencia. Este desarrollo de resistencia de P. aeruginosa es cada vez más frecuente en los hospitales de todo el mundo, y puede convertirse en un importante problema de salud pública. La epidemiología de la adquisición y propagación de la Pseudomonas aeruginosa multiresistente es compleja estando involucrados múltiples factores, entre los más importantes son las deficiencias en la aplicación de las directrices de control de la infección y el uso de antibióticos de amplio espectro. La mayoría de los estudios realizados previamente en P. aeruginosa se han centrado en unidades de cuidados intensivos, o en, Pseudomonas resistentes a determinados antibióticos, como quinolonas o carbapenémicos, o a sitios específicos de infección como neumonía asociada a la ventilación mecánica. Asimismo, los estudios para identificar los factores de riesgo de adquisición y/o de recidiva de Pseudomonas resistentes han utilizado, generalmente, la metodología de control de casos o estudio de brotes utilizando como control a pacientes con P. aeruginosa sensible. Esta metodología tiene importantes sesgos y limitaciones, puede sobre estimar la contribución que tiene en la resistencia la exposición previa a antibióticos o puede falsamente implicar a otros factores de riesgo. En el Hospital del Mar, los primeros aislamientos de pacientes con Pseudomonas aeruginosa multiresistente solo sensibles a amikacina y la colistina se identificaron en el año 2001. A partir de entonces el número de casos fue en aumento, por este motivo se generó el estudio de este micro organismo, tanto de sus características epidemiológicas, factores de riesgo relacionados, aspectos clínicos y terapéuticos. Métodos. La presente tesis se ha realizado por compendio de publicaciones: 1) Montero M, et al (2009) Mortality of COPD patients infected with multi-resistant Pseudomonas aeruginosa: a case and control study. Infection, 37(1): 16-9. 2) Montero M, et al (2009) Effectiveness and safety of colistin for the treatment of multidrug-resistant Pseudomonas aeruginosa infections. Infection, 37:461-465. 3) Montero M, et al (2010) Risk factors for multidrug-resistant Pseudomonas aeruginosa acquisition. Impact of antibiotic use in a double case-control study. Eur J Clin Microbiol Infect Dis, 29:335-9. Resultados y conclusiones. Las principales conclusiones pueden resumirse en tres aspectos principales. Desde un punto de vista clínico destaca que el aislamiento de Pseudomonas aeruginosa multiresistente se asocia con mayor mortalidad en los pacientes con EPOC y que en estos pacientes la erradicación es muy difícil de conseguir. Desde el punto de vista terapéutico destaca que la colistina fue efectiva en el 72 % de los pacientes con infecciones por P.aeruginosa multiresistente, la toxicidad renal fue del 8,3%, la combinación de colistina nebulizada y endovenosa no se asoció con mejor respuesta clínica, la erradicación microbiológica fue solo del 35%. Desde el punto de vista epidemiológico destaca que los factores de riesgo relacionados con P. aeruginosa multiresistente frente a la ausencia de infección por P. aeruginosa fueron: el sexo masculino, más de tres hospitalizaciones, la presión de colonización, EPOC, índice de gravedad y uso previo de quinolonas y carbapenems. En el modelo que comparó P. aeruginosa multiresistente con P. aeruginosa sensible los factores de riesgo relacionados fueron el uso previo de quinolonas, carbapenems y penicilinas antipseudomónicas, desapareciendo el EPOC y manteniéndose el número de hospitalizaciones, presión de colonización e índice de gravedad.
Background. Pseudomonas aeruginosa is non-fermentative Gram-negative bacillus responsible for a high proportion of infections acquired in hospitals, particularly in intensive care units (ICUs). Infections with P. aeruginosa are often severe and difficult to treat because of high level of resistance. The development of resistance of P. aeruginosa is increasing in the hospital environment worldwide, and can become a major public health problem. The epidemiology of acquisition and spread of multidrug-resistant Pseudomonas aeruginosa is complex and several factors may be involved, the most important are the shortcomings in the implementation of the guidelines of infection control and the use of broad-spectrum antibiotics. Most of the previous studies were focussed on particular environments such as the intensive care unit or in specific antibiotic resistances pattern, mainly quinolone-resistant and carbapenems-resistant, or specific infection sites such ventilator-associated pneumonia. Most studies have used case-control methodology or have investigated outbreaks. The case-control studies usually compared susceptible to resistant microorganisms. This methodology has significant biases and limitations, may overestimate the contribution of previous exposure to antibiotics in the development of resistance or may falsely implicate other risk factors for the acquisition of this pattern of resistance. In our center (Hospital del Mar), the first isolates of multiresistant Pseudomonas aeruginosa were identified in 2001.Sinse then the number of cases was increasing, that is why the study was generated from this strain. The epidemiological characteristics, the risk factors, the clinical and therapeutic aspects were analyzed. Methods. This thesis has been carried by publications: 1) Montero M, et al (2009) Mortality of COPD patients infected with multi-resistant Pseudomonas aeruginosa: a case and control study. Infection, 37 (1): 16-9. 2) Montero M, et al (2009) Effectiveness and safety of colistin for the treatment of multidrug-resistant Pseudomonas aeruginosa infections. Infection, 37:461-465. 3) Montero M, et al (2010) Risk factors for multidrug-resistant Pseudomonas aeruginosa acquisition. Impact of antibiotic use in a double case-control study. Eur J Clin Microbiol Infect Dis, 29:335-9. Results and Conclusions. The main findings can be summarized in three main aspects. In the first study, it is of note a high mortality rate associated with multi-resistant Pseudomonas aeruginosa in patients with COPD acute exacerbation admitted to general ward and found a higher proportion of persistence of multi-resistant Pseudomonas aeruginosa. In the second study related to the the treatment of multi-resistant Pseudomonas aeruginosa, the clinical outcome was favorable in 72%, 8.3% of patients developed nephrotoxicity and the combination of nebulized and intravenous colistin was not associated with a better response to therapy. Finally, the last study analyzed the risk factors associated with multi-resistant Pseudomonas aeruginosa with the methodology of double case-control, the risk factors associated when comparing controls without Pseudomonas aeruginosa infection were male sex, more than three previous hospitalizations, simultaneous multi-resistant Pseudomonas aeruginosa isolates in the hospital, COPD, severity of illness and previous use of quinolones and carbapenems. When comparing multi-resistant Pseudomonas aeruginosa infection versus susceptible Pseudomonas aeruginosa, the odds ratio (OR) for quinolonas was much higher than observed in the previous model, and COPD disappeared as a risk factor for multi-resistant strain.

Les mucines bronchiques humaines sont des molécules d'une extraordinaire diversité notamment au niveau de leur chaînes glycanniques. La glycosylation et la sulfatation des mucines bronchiques humaines sont modifiées dans la mucoviscidose et une étude récente suggère que les modifications de glycosylation seraient, en partie, liée à l'inflammation importante de la muqueuse bronchique des sujets malades. Dans la première partie de notre travail de thèse, nous démontrons qu'une cytokine, le TNFα, augmente l'activité et l'expression de glycosyl- et sulfo-transférases responsable de la biosynthèse de l'épitope Lewis x et de ses dérivés sialylés et/ou sulfatés dans la muqueuse bronchique humaine. Dans la seconde partie de notre travail, nous nous sommes intéressés aux possibles implications d'anomalies de glycosylation et de sulfatation des mucines bronchiques dans l'adhésion de Pseudomonas aeruginosa aux mucines. Nous avons plus précisément démontré que les glycotopes sialyl-Lewis x et 6-sulfo-sialyl-Lewis x sont des récepteurs pour P. Aeruginosa. Nous démontrons aussi que la protéine FliD, protéine de l'extrémité du flagelle qui est impliqué dans l'adhésion aux mucines bronchiques, reconnaît les glycotopes Lewis x et sialyl-Lewis x. De plus, nos résultats suggèrent qu'un autre composant du flagelle de certaines souches de P. Aeruginosa, la flagelline, intervient également dans l'adhésion aux mucines bronchiques
Human bronchial mucins are a very broad family of polydisperse high molecular weight glycoproteins. The glycosylation and sulfation of human airway mucins are modified in cystic fibrosis and a recent work suggests that these modifications are related to the severe inflammation of bronchial mucosa obtained from patients. In a first part of our work, we demonstrated that a cytokine, the TNF, increased the activities and the expression of Lewis x epitope and its sialylated and/or sulfated derivatives in the human mucosa. In a second part, we investigated the implications of glycosylation and sulfation alterations of bronchial mucins in the binding of Pseudomonas aeruginosa to mucins. We demonstrated that sialyl-Lewis x and 6-sulfo-sialyl-Lewis x epitopes are receptors for Pseudomonas aeruginosa. We also demonstrated that FliD protein, the flagellar cap protein of Pseudomonas aeruginosa which is a mucin-specific adhesin, recognise the sialyl-Lewis x epitopes. Another flagellar components of some Pseudomonas aeruginosa strains, the flagellin, may be involved in the adhesion to bronchial mucins

This item is only available electronically.
The stable carbon (ẟ13C) and oxygen (ẟ18O) isotopic composition of bioapatite from fossilised mammalian tooth material is a well-established proxy for the reconstruction of palaeovegetation and palaeoclimate. The use of small mammals, in particular rodents, has been overlooked in the past for such studies. High abundances of fossilised rodent remains deposited by avian predators in cave deposits, such as Blanche Cave in the Naracoorte Caves World Heritage Area (NCWHA), gives researchers easy access to fossil materials, to which a temporal scale of climate and vegetation change can be reconstructed. ẟ18O and ẟ13C analyses were performed on crushed incisors of three species of Pseudomys (P. auritus, P. australis and P. shortridgei) over the upper 27 layers from Blanche Cave, NCWHA. The relative abundances of the three species were collected from each layer and compiled into climatic-stratigraphic units: pre-glaciation (layers 27-25), early-glaciation (layers 24-20), Last Glacial Maximum (layers 19-15) and deglaciation (layers 13-1). The carbonate-bound component of the bioapatite was analysed for ẟ13C and ẟ18OCO3, as well as the additional analysis of phosphate bound oxygen (ẟ18OPO4) using isotope ratio mass spectrometry. Isotopic signatures from ẟ13C and ẟ18O were used to reconstruct palaeoclimate and palaeovegetation over the four climatic-stratigraphic units, which were compared to existing palaeoclimate studies. As rodents are commonly abundant in fossil deposits, they have the potential of being used to determine climatic and vegetation change associated with extinction events, such as the megafauna extinction in Australia.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018