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C Anthony Hart

Publications and source records attributed to C Anthony Hart.

86 records · Page 5Linked to original sources
PubMed2002

Distribution of type III secretion gene clusters in Burkholderia pseudomallei, B. thailandensis and B. mallei.

Burkholderia pseudomallei, the causative agent of melioidosis, carries a cluster of genes closely related in organisation to the type III secretion (TTS) system gene clusters of the plant pathogens Ralstonia solanacearum and Xanthomonas spp. The TTS gene cluster (TTS1) is present only in B. pseudomallei and not in avirulent B. thailandensis. Adjacent to the gene cluster encoding putative secreton structural proteins lie a number of open reading frames (ORFs) encoding putative proteins with little or no homology to known proteins, with the exception of one predicted protein with homology to Pseudomonas syringae HrpK. In both R. solanacearum and Xanthomonas spp., genes in this location encode secreted effector proteins. RT-PCR analysis indicated that TTS genes, including two of these ORFs, are expressed in broth at 37 degrees C. Analysis of genome sequence data identified a second cluster of TTS genes (TTS2) present in both B. pseudomallei and B. mallei (99% identity). However, B. mallei appears to lack the TTS1 gene cluster. PCR assays indicated that TTS2 was also present in B. thailandensis. TTS1 and TTS2 are similar in gene organisation, but nucleotide sequences are sufficiently divergent to suggest that the two TTS systems may have different roles.

Amino Acid Sequence↗
PubMed2002

Distribution of fim3 and flaA TTGE sequence types amongst isolates of Bordetella bronchiseptica from different host animals.

Isolates of Bordetella bronchiseptica associated with different animal hosts were analysed by fim3 and flaA genotyping by temporal temperature gradient gel electrophoresis (TTGE). All the isolates from cats (n = 138), dogs (n = 42) and pigs (n = 13) could be assigned to one of two fim3 and one of three flaA TTGE sequence types, respectively. Two avian isolates and a marmoset isolate exhibited novel fim3 sequence types. Dominant but different TTGE sequence types were apparent in isolates from dogs and pigs for both fim3 (87.5% and 100%, respectively, of isolates were the dominant type) and flaA (95% and 92%, respectively, of isolates were the dominant type). There was a wider distribution of TTGE sequence types amongst cat isolates. As both fimbriae and flagella have been implicated in adherence of bordetellae to host cells, sequence variations in fimbrial proteins and FlaA may have a role to play in host preferences.

Amino Acid Sequence↗
PubMed2002

Use of subtractive hybridization to identify a diagnostic probe for a cystic fibrosis epidemic strain of Pseudomonas aeruginosa.

A multiresistant strain of Pseudomonas aeruginosa is widespread among cystic fibrosis (CF) patients attending clinics in Liverpool, United Kingdom. Suppression subtractive hybridization was used to identify sequences present in the Liverpool CF epidemic strain but absent from strain PAO1. Using dot blot and PCR amplification assays, the prevalence of such sequences among a panel of CF isolates was determined. Several sequences were found only in the Liverpool epidemic strain. Some sequences were present in the Liverpool epidemic strain and in a minority of other isolates, including sequences with homology to genes implicated in O6 serotype and siderophore production. The Liverpool epidemic strain and 81% of nonepidemic isolates contained a sequence identified as part of the PAGI-1 genomic island. Other strains implicated in epidemic spread, which were from Manchester, United Kingdom, and Melbourne, Australia, were also screened. None of the sequences identified was present in the Manchester strain. However, one of two Melbourne strains contained some of the sequences found in the Liverpool epidemic strain. All isolates implicated in epidemic spread and 76% of sporadic isolates contained the exoS gene. A sequence present in all isolates of the Liverpool epidemic strain was used to develop a diagnostic PCR test for identification of the strain from colonies or directly from sputum samples.

Cloning, Molecular↗
PubMed2002

Treatment of subacute sclerosing panencephalitis with interferon-alpha, ribavirin, and inosiplex.

Subacute sclerosing panencephalitis is an almost universally fatal late complication of measles infection for which there is no established treatment. We report a patient with subacute sclerosing panencephalitis who was bed-bound and ataxic and had a left hemiparesis and frequent myoclonus. He was started on a new regimen consisting of intraventricular interferon-alpha (starting at 100,000 U/m2/day, building up to 1 million U/m2/day), ribavirin (60 mg/kg/day intravenously), and inosiplex (3 g/day) and improved markedly. At 10 weeks, the intraventricular reservoir was removed because of bacterial infection, and he was discharged home on oral ribavirin (1200 mg/kg/day) and inosiplex. He continued to improve as judged by neurologic examination, functional independence measurement, neuropsychometry and single photon emission computed tomography (SPECT) imaging. However, after 10 months, he deteriorated suddenly and died before further intraventricular treatment could be instituted. Further trials are needed to evaluate long-term combination therapy in subacute sclerosing panencephalitis.

Administration, Oral↗
PubMed2002

Detection of enteric adenoviruses in children with acute gastro-enteritis in Blantyre, Malawi.

In a 2-year hospital-based study of acute gastro-enteritis in children under 5 years of age in Blantyre, Malawi, enteric adenoviruses were detected by enzyme immunoassay in 11 (1.4%) of 786 inpatients and in 12 (3%) of 400 outpatients. Enteric adenoviruses were also detected in four (0.8%) children without diarrhoea admitted to hospital. Enteric adenoviruses account for only a minority of cases of diarrhoea in children hospitalised in Malawi.

Acute Disease↗
PubMed2002

Cryptosporidium muris infection in an HIV-infected adult, Kenya.

We describe a case of Cryptosporidium muris infection in an HIV-infected adult with diarrhea in Kenya. Sequence analysis of an 840-bp region of the 18S rRNA gene locus demonstrated the isolate had 100% nucleotide identity with C. muris recovered from a rock hyrax, 98.8% with a C. muris "calf" isolate, 95.5% with C. serpentis, but only 87.8% with C. parvum "human" type.

AIDS-Related Opportunistic Infections↗
PubMed2002

Excretion of vancomycin-resistant enterococci by wild mammals.

A survey of fecal samples found enterococcal excretion in 82% of 388 bank voles (Clethrionomys glareolus), 92% of 131 woodmice (Apodemus sylvaticus), and 75% of 165 badgers (Meles meles). Vancomycin-resistant enterococci, all Enterococcus faecium of vanA genotype, were excreted by 4.6% of the woodmice and 1.2% of the badgers, but by none of the bank voles.

Animals↗
PubMed2001

Type III secretion systems and pathogenicity islands.

Some bacterial pathogens have evolved by acquiring pathogenicity islands (PIs), which are clusters of genes encoding virulence traits. PIs encoding the secretion of effector molecules via type III secretion (TTS) systems have been discovered in several gram-negative pathogens. TTS systems are involved in contact-dependent secretion of virulence factors and can facilitate delivery of toxins directly into target cells. The expanding list of bacteria found to contain clusters of TTS genes includes members of the genera Yersinia, Salmonella, Shigella, Escherichia, Pseudomonas, Bordetella, Burkholderia, Chlamydia and a number of plant pathogens or symbionts. This review discusses the current knowledge of the role of TTS PIs in pathogenicity, the genetic organisation and evolution of such systems,and the potential for using TTS systems as targets for novel treatments.

Bacterial Proteins↗
PubMed2001

Flagellin gene PCR-RFLP analysis of a panel of strains from the Burkholderia cepacia complex.

Burkholderia cepacia, an important opportunist pathogen, is genetically heterogeneous. The B. cepacia complex has been subdivided into a number of genospecies or genomovars. A flagellin gene PCR-RFLP method was applied to a representative panel of strains of known genomovar. The technique was able to distinguish strains of B. multivorans from other members of the B. cepacia complex on the basis of amplicon size (typical of type I rather than type II flagellins) with the exception of one genomovar I strain. There was considerable variation in RFLP patterns amongst the panel of strains; only two pairs of strains were indistinguishable with both HaeIII and MspI digestion. Where RFLP patterns matched with both enzymes or a single enzyme, matching strains were always in the same genomovar. It was possible to distinguish the UK cystic fibrosis epidemic strain from all other members of the panel, including nine other genomovar III strains. The level of variation suggests that flagellin genotyping is a useful method for discriminating between B. cepacia strains.

Bacterial Typing Techniques↗
PubMed1999

A novel mucin-sulphatase activity found in Burkholderia cepacia and Pseudomonas aeruginosa.

Lung infections due to Burkholderia cepacia and Pseudomonas aeruginosa in patients with cystic fibrosis (CF) are common, are associated with respiratory morbidity and are a cause of mortality. Respiratory mucin in CF patients is highly sulphated, which increases its resistance to bacterial degradation. Desulphation increases the susceptibility of mucin to degradation by bacterial glycosidases and proteinases, and subsequent deglycosylation may facilitate bacterial colonisation by increasing available substrates and binding sites. This study determined whether clinical and environmental strains of B. cepacia and P. aeruginosa had the ability to desulphate mucin. Mucin-sulphatase activity was tested by incubating bacterial cell suspensions with 35S-sulphated mucins purified from LS174T and HT29-MTX human colon carcinoma cell lines. These mucins were also used to test for differences in substrate specificities. Mucin-sulphatase activity was detected in all nine B. cepacia strains and in four of six P. aeruginosa strains. There was strain variability in the level of mucin-sulphatase activity. Aryl-sulphatase activities of Pseudomonas isolates (determined with methylumbelliferyl sulphate) were c. 20-fold higher than those of B. cepacia strains, and were independent of mucin-sulphatase activity. This is the first report to demonstrate desulphation of mucin by B. cepacia and P. aeruginosa. It is concluded that B. cepacia and P. aeruginosa produce one or more cell-bound glycosulphatase(s), in addition to aryl-sulphatase activity. Mucin-sulphatase activity of B. cepacia and P. aeruginosa may contribute to their association with airway infections in patients with cystic fibrosis.

Arylsulfatases↗
PubMed1999

Analysis of fliC variation among clinical isolates of Burkholderia cepacia.

PCR and restriction fragment length polymorphism (RFLP) typing of flagellin genes (fliC) from 57 clinical isolates of Burkholderia cepacia indicated that only type 11 flagellins were present. Twenty-two isolates previously identified as the epidemic UK cystic fibrosis strain were indistinguishable by this method, as were 11 isolates from a pseudo-outbreak in Senegal. Other clinical isolates, including 19 from disparate sources in Malaysia, were separated into nine fliC RFLP groups, exhibiting a large degree of divergence. When isolates were indistinguishable by fliC genotyping, their similarity was confirmed by whole genome macro-restriction analysis with pulsed-field gel electrophoresis following XbaI digestion. The variation in fliC sequences of B. cepacia was far greater than that with B. pseudomallei, supporting the view that 'B. cepacia', as currently defined, may comprise several different genomic species.

Burkholderia Infections↗
PubMedDate not supplied

Where is the meningitis belt? Defining an area at risk of epidemic meningitis in Africa.

Mapping an area at risk of epidemics of meningococcal meningitis in Africa has significant implications for their prevention and case treatment, through the targeted development of improved surveillance systems and control policies. Such an area was described using information obtained from published and unpublished reports of meningitis epidemics between 1980 and 1999 and cases of meningococcal disease reported by surveillance systems to WHO. The Sahel bore the greatest epidemic burden, with over two-thirds of documented outbreaks and high attack rates. In addition to those already in the Meningitis Belt, countries affected included Guinea-Bissau, Guinea, Côte d'Ivoire, Togo, the Central African Republic and Eritrea. Elsewhere epidemics were reported from a band of countries around the Rift Valley and Great Lakes regions extending as far south as Mozambique and from here west to Angola and Namibia in southern Africa. The cumulative pan-continental analysis provided evidence of an epidemic-susceptible area which extends beyond the region accepted as the Meningitis Belt and which, moreover, may be partially determined by the physical environment, as shown by a striking correspondence to the 300-1100-mm mean annual rainfall isohyets.

Africa↗
PubMedDate not supplied

Rotavirus infection in Saudi Arabia.

BACKGROUND: Human rotavirus, an important causative agent of severe gastroenteritis in infants and young children worldwide, leads to high morbidity in both developing and developed countries, including Saudi Arabia, and high mortality in developing countries. Effective control depends upon an accurate understanding of disease burden and the relative importance of circulating serotypes. METHODS: We examined the epidemiology and disease burden of rotavirus in Saudi Arabia through a review of 22 published studies of rotavirus and the aetiology of diarrhoea carried out from 1982 to 2003. RESULTS: The prevalence of rotavirus infection ranged between 10% to 46% with a median of 30%. Most cases were among children less than 2 years of age, and particularly in the first year of life. There were significant differences in seasonality within Saudi Arabia, with increased infection during winter in some cities and during summer in others. G1 was the predominant serotype followed by G4, G3 and G2, in 4 studies where strains had been G-typed. The prevalence of nontypeable strains ranged from 11.0% to 31.3%. No data were available on P types. Results of electropherotyping in 4 studies revealed that the long electropherotype was predominant. CONCLUSION: Rotavirus is an important cause of severe diarrhoea in Saudi children. However, the available data on rotavirus strains in circulation are limited and there is an urgent need for up-to-date and comprehensive studies to evaluate rotavirus strains in circulation and identify unusual types that could be incorporated into future vaccines.

Antigens, Viral↗