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C A Hart

Publications and source records attributed to C A Hart.

At least 37 records · Page 2Linked to original sources
PubMed2004

Frequency and spatial distribution of environmental Campylobacter spp.

Humans are exposed to Campylobacter spp. in a range of sources via both food and environmental pathways. For this study, we explored the frequency and distribution of thermophilic Campylobacter spp. in a 10- by 10-km square rural area of Cheshire, United Kingdom. The area contains approximately 70, mainly dairy, farms and is used extensively for outdoor recreational activities. Campylobacter spp. were isolated from a range of environmental samples by use of a systematic sampling grid. Livestock (mainly cattle) and wildlife feces and environmental water and soil samples were cultured, and isolates were presumptively identified by standard techniques. These isolates were further characterized by PCR. Campylobacter jejuni was the most prevalent species in all animal samples, ranging from 11% in samples from nonavian wildlife to 36% in cattle feces, and was isolated from 15% of water samples. Campylobacter coli was commonly found in water (17%) and sheep (21%) samples, but rarely in other samples. Campylobacter lari was recovered from all sample types, with the exception of sheep feces, and was found in moderate numbers in birds (7%) and water (5%). Campylobacter hyointestinalis was only recovered from cattle (7%) and birds (1%). The spatial distribution and determinants of C. jejuni in cattle feces were examined by the use of model-based spatial statistics. The distribution was consistent with very localized within-farm or within-field transmission and showed little evidence of any larger-scale spatial dependence. We concluded that there is a potentially high risk of human exposure to Campylobacter spp., particularly C. jejuni, in the environment of our study area. The prevalence and likely risk posed by C. jejuni-positive cattle feces in the environment diminished as the fecal material aged. After we took into account the age of the fecal material, the absence or presence of rain, and the presence of bird feces, there was evidence of significant variation in the prevalence of C. jejuni-positive cattle feces between grazing fields but no evidence of spatial clustering beyond this resolution. The spatial pattern of C. jejuni is therefore consistent with that for an organism that is ubiquitous in areas contaminated with cattle feces, with a short-scale variation in infection intensity that cannot be explained solely by variations in the age of the fecal material. The observed pattern is not consistent with large-scale transmission attributable to watercourses, wildlife territories, or other geographical features that transcend field and farm boundaries.

Animals↗
PubMed2004

Genotypic and antibiotic susceptibility characteristics of a Campylobacter coli population isolated from dairy farmland in the United Kingdom.

Campylobacter infections are the most common cause of bacterial enteritis in humans, and nearly 8% of such infections are caused by Campylobacter coli. Most studies have concentrated on Campylobacter jejuni, frequently isolated from intensively farmed poultry and livestock production units, and few studies have examined the spread and relatedness of Campylobacter across a range of geographical and host boundaries. Systematic sampling of a 100-km2 area of mixed farmland in northwest England yielded 88 isolates of C. coli from a range of sample types and locations, and water was heavily represented. Screening for antibiotic resistance revealed a very low prevalence of resistance, while genotyping performed by using three methods (flaA PCR restriction fragment length polymorphism [RFLP], pulsed-field gel electrophoresis [PFGE], and fluorescent amplified fragment length polymorphism [fAFLP]) provided insights into the genomic relatedness of isolates from different locations and hosts. Isolates were classified into 23 flaA groups, 34 PFGE groups, and five major fAFLP clusters. PFGE banding analysis revealed a high level of variability and no clustering by sample type. fAFLP and flaA analyses successfully grouped the isolates by sample type. We report preliminary findings suggesting that there is a strain of C. coli which may have become adapted to survival or persistence in water and that there is a group of mainly water-derived isolates from which unusual flaA PCR fragments were recovered.

Agriculture↗
PubMed2004

Increased morbidity associated with chronic infection by an epidemic Pseudomonas aeruginosa strain in CF patients.

BACKGROUND: Chronic pulmonary infection with transmissible Pseudomonas aeruginosa strains in individuals with cystic fibrosis (CF) has been reported, raising issues of cross infection and patient segregation. The first such strain to be described (the Liverpool epidemic strain, LES) is now widespread in many UK CF centres. However, whether such infection carries a worse prognosis is unknown. To address this, the clinical course of a group of CF patients chronically infected by LES was compared with that in patients harbouring unique strains. METHODS: Using P aeruginosa strain genotyping, two cohorts of CF patients attending the Liverpool CF service were identified who were LES positive or negative in 1998 and remained so until 2002. From these, two groups of 12 patients were matched in 1998 for age, spirometric parameters, and nutritional state and their clinical course was followed for 5 years. Patients chronically infected with Burkholderia cepacia were excluded. RESULTS: Patients chronically infected with LES had a greater annual loss of lung function than those not chronically infected by LES (mean difference between groups -4.4% (95% CI -8.1 to -0.9; p<0.02)), and by 2002 their percentage predicted forced expiratory volume in 1 second (FEV1) was worse (mean 65.0% v 82.6%, p<0.03). Their nutritional state also deteriorated over the study period (mean difference between groups in body mass index -0.7 (95% CI -1.2 to -0.2; p<0.01)), such that by 2002 they were malnourished compared with LES negative patients (mean BMI 19.4 v 22.7, p<0.02). CONCLUSIONS: Chronic infection with the Liverpool epidemic P aeruginosa strain in CF patients confers a worse prognosis than infection with unique strains alone, confirming the need for patient segregation. Since this strain is common in many CF units, strain identification in all CF centres is essential. This can only be carried out using genomic typing methods.

Body Mass Index↗
PubMed2004

Pro- and anti-inflammatory responses in respiratory syncytial virus bronchiolitis.

Respiratory syncytial virus (RSV) bronchiolitis is an important cause of severe respiratory disease in infants. This study aimed to characterise changes in pulmonary pro- and anti-inflammatory responses in infants with RSV bronchiolitis over the course of the illness. On the day of intubation (Day 1) and the day of extubation (Day X), nonbronchoscopic bronchoalveolar lavage was performed on term and preterm infants ventilated for RSV bronchiolitis and on control infants on Day 1. Tumour necrosis factor (TNF)-alpha, soluble TNF receptor (sTNFR) and interleukin (IL)-6 messenger ribonucleic acid (mRNA) and protein were measured. Twenty-four infants, born at term and 23 infants born preterm with RSV bronchiolitis and 10 controls were recruited. TNF-alpha and IL-6 mRNA and protein in infants with bronchiolitis were greater than the control group on Day 1. In preterm infants, who were ventilated for longer than term infants, TNF-alpha and IL-6 proteins decreased between Day 1 and Day X. Concentrations of sTNFRs differed between groups on Day 1, but levels did not change between Day 1 and Day X. Large amounts of tumour necrosis factor-alpha and interleukin-6 in the respiratory syncytial virus-infected lung suggest important roles for these cytokines in the pathogenesis of respiratory syncytial virus bronchiolitis. The decrease in tumour necrosis factor-alpha and interleukin-6 protein in preterm infants may reflect the prolonged clinical course seen in these infants.

Bronchiolitis, Viral↗
PubMed2004

Molecular analysis of multi-drug resistant Salmonella typhi from urban paediatric population of Bangladesh.

The prevalence and genetic basis of resistance of multi-drug resistant (MDR) S typhi strains from an urban paediatric population was determined. Blood cultures performed on 109 cases of suspected typhoid fever yielded 30(27.5%) S typhi isolates. Of these, 20(67%) S typhi isolates were resistant to the common antimicrobials used in Bangladesh, eg, chloramphenicol, ampicillin, cotrimoxazole, streptomycin and tetracycline, while 6(20%) isolates were resistant only to streptomycin. However, all the isolates were sensitive to fluquinolones and cephalosporins. Molecular analysis demonstrated that all MDR strains possessed a single large transferable 98 MDal plasmid. On conjugation, chloramphenicol, ampicillin and cotrimoxazole resistance was transferred from MDR strains to E coli K-12. Restriction endonuclease analysis of plasmid DNA showed similar digest profiles of all 5 selected donors and their transconjugants. This trend of increasing resistant strains of S typhi, especially by the transferable plasmid is of major public health concern.

Adolescent↗
PubMed2003

A flowchart for managing sexually transmitted infections among Nigerian adolescent females.

OBJECTIVE: To devise a flowchart suitable for assessing risk of trichomoniasis, chlamydia and gonorrhoea in an adolescent population, not all of whom will be sexually experienced or currently in a relationship. METHODS: The data used to derive the flowchart were generated from cross-sectional microbiological surveys of girls aged 14-19 years in Port Harcourt, Nigeria. The flowchart screened on the basis of: (i) sexual experience; (ii) recent sexual activity; (iii) a positive urine leukocyte esterase (LE) test; and (iv) among LE negatives, a history of malodorous/pruritic discharge. FINDINGS: Using this flowchart, we found that 26.2% of all adolescents screened would receive treatment for cervicitis and vaginitis. Chlamydial, gonococcal, and trichomonal infections were correctly diagnosed in 37.5%, 66.7%, and 50% of the cases, respectively. CONCLUSION: Although the flowchart is more suitable for an adolescent population than the vaginal discharge algorithm used in syndromic management protocols, it still lacks precision and needs adapting to local settings.

Adolescent↗
PubMed2003

Applications of Fourier transform infrared microspectroscopy in studies of benign prostate and prostate cancer. A pilot study.

Fourier transform infrared (FTIR) microspectroscopy has been applied to a study of prostate cancer cell lines derived from different metastatic sites and to tissue from benign prostate and Gleason-graded malignant prostate tissue. Paraffin-embedded tissue samples were analysed by FTIR, after mounting onto a BaF(2) plate and subsequent removal of wax using Citroclear followed by acetone. Cell lines were analysed as aliquots of cell suspension held between two BaF(2) plates. It was found that the ratio of peak areas at 1030 and 1080 cm(-1), corresponding to the glycogen and phosphate vibrations respectively, suggests a potential method for the differentiation of benign from malignant cells. The use of this ratio in association with FTIR spectral imaging provides a basis for estimating areas of malignant tissue within defined regions of a specimen. Initial chemometric treatment of FTIR spectra, using the linear discriminant algorithm, demonstrates a promising method for the classification of benign and malignant tissue and the separation of Gleason-graded CaP spectra. Using the principle component analysis, this study has achieved for the first time the separation of FTIR spectra of prostate cancer cell lines derived from different metastatic sites.

Adenocarcinoma↗
PubMed2003

Infection control measures for adult cardiac surgery in the UK--a survey of current practice.

The aim of the study was to define current UK practice for antimicrobial prophylaxis and preoperative screening for bloodborne viruses and methicillin-resistant Staphylococcus aureus (MRSA) before routine cardiac surgery. An e-mail survey was sent to the Association of Cardiothoracic Anaesthetists (ACTA) Linkmen in all 36 UK adult cardiac surgical units, during May 2001. Questions were asked regarding MRSA, hepatitis B, C and human immunodeficiency virus (HIV) screening. Regarding antimicrobial prophylaxis questions were asked regarding agent(s), dose, frequency and duration of use for coronary artery and value surgery. Responses were received from 29 units (response rate 81%). There was a wide variety of practices for all units surveyed. For MRSA screening, 19 units (65%) screened all patients before surgery, but two (7%) screened none, with the remaining eight units (28%) screening selected high-risk groups. Regarding screening for bloodborne viruses: eight units (28%) tested all patients routinely for hepatitis B, 11 units (39%) selectively tested only high-risk patients and transplant recipients. No units tested for hepatitis C and HIV infection routinely. All units used prophylactic antibiotics routinely, but the type and number of agents, along with dose and duration of therapy all varied widely. For coronary artery bypass graft (CABG) surgery, a single agent was used by 16 units (55%), two agents by 12 units (41%) and three agents by one unit (4%). There is a wide variation in infection control practice in adult cardiac units throughout the UK. Rationalization of preoperative screening and use of prophylactic antibiotics, by adopting nationally agreed practice guidelines, could significantly reduce costs and potentially reduce the incidence of resistant organisms.

Adult↗
PubMed2003

Fosfomycin therapy for multiresistant Pseudomonas aeruginosa in cystic fibrosis.

BACKGROUND: Increasing resistance to standard antibiotics has been demonstrated in CF patients colonised by Pseudomonas aeruginosa. The antibiotic Fosfomycin has a unique mode of action against this organism, and may protect against aminoglycoside mediated renal and ototoxic effects. However, there is little published experience of this drug in IV form, and it is not licensed for use in the UK. METHODS: In combination with other antibiotics, we used Fosfomycin to treat 30 pulmonary exacerbations in 15 adult CF patients colonised by P. aeruginosa, mainly multiresistant strains. All patients gave informed consent. We cultured sputum prior to treatment and measured spirometry, renal function, and symptoms before and after treatment, and recorded any side effects. RESULTS: One patient developed nausea and Fosfomycin treatment was withdrawn. The remaining patients showed clinical resolution of their chest exacerbations (mean FEV1% predicted: pre 41.1 vs. post 49.4, P<0.001). Although there was a statistical increase in plasma urea (pre 3.9 mmol/l vs. post 4.3, P<0.03), this was still within the normal range. Plasma creatinine was unchanged. CONCLUSIONS: This study shows that IV Fosfomycin is well tolerated by adult patients with CF and can be useful in the treatment of those colonised with multiresistant P. aeruginosa.

Adolescent↗
PubMed2003

Molecular characterization and distribution of virulence-associated genes amongst Aeromonas isolates from Libya.

AIMS: The aim of the study was to type 52 Aeromonas spp. isolates from chicken carcasses, children with diarrhoea and a hospital environment in Libya, and to determine the distribution of putative virulence genes amongst them. METHODS AND RESULTS: Macrorestriction analysis using pulsed-field gel electrophoresis (PFGE) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of 16S rRNA and aroA genes were used to type the isolates. Whereas 30 of 32 chicken isolates were identified as Aeromonas veronii, eight of 12 environmental isolates were Aer. caviae. Three species were identified amongst the eight isolates from children. Aeromonas veronii and Aer. caviae isolates could be divided into eight and five PFGE types, respectively. All species could be further subtyped into one of 21 aroA PCR-RFLP groups. Aerolysin-like haemolysin or enterotoxin gene sequences were detected in all the isolates. Overall carriage rates for hlyA and alt were 77 and 75%, respectively. CONCLUSIONS: Seven of eight isolates from children were of different subtypes, indicating a lack of any common source of acquisition. Isolates of common molecular type did not share identical distributions of putative virulence genes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the effectiveness of using molecular typing to identify and study genetic variation amongst Aeromonas isolates.

Aeromonas↗
PubMed2003

Purification of ovine neutrophils and eosinophils: Anaplasma phagocytophilum affects neutrophil density.

Studies on the functions of ovine granulocytes require pure and functionally active populations of neutrophils and eosinophils. This report describes an improved technique for the separation of neutrophils and eosinophils from the peripheral blood of sheep infected with Anaplasma phagocytophilum and from normal sheep. After centrifugation and discarding the buffy coat layer, which contains the bulk of mononuclear cells, neutrophils with a high degree of purity (94.87 [+/-1.7]%, n=9) and good yield (69 [+/-9]%, n=9) were obtained by density gradient centrifugation on Percoll with a density of 1.09 g/ml (65%). However, this density was not suitable for neutrophils obtained from sheep during the peak period of A. phagocytophilum bacteraemia. Improved purity of infected neutrophils was obtained when the leucocytes were separated on Percoll with a density of 1.08 g/ml (55%). Relatively good purity of eosinophils was obtained when leucocytes from normal sheep were separated on Percoll with a density of 1.10 g/ml (70%). Ovine eosinophils formed a distinct band just below the band of mononuclear cells when a continuous Percoll gradient with a density of 1.10 g/ml was used. The purity of the eosinophils obtained was 87.7 (+/-12.5)% (n=6; range 64.1-97.6%), with a mean recovery rate of 61.9 (+/-20.3)%.

Anaplasma phagocytophilum↗
PubMed2003

Bacterial diversity in cases of lung infection in cystic fibrosis patients: 16S ribosomal DNA (rDNA) length heterogeneity PCR and 16S rDNA terminal restriction fragment length polymorphism profiling.

The leading cause of morbidity and mortality in cystic fibrosis (CF) patients stems from repeated bacterial respiratory infections. Many bacterial species have been cultured from CF specimens and so are associated with lung disease. Despite this, much remains to be determined. In the present study, we characterized without prior cultivation the total bacterial community present in specimens taken from adult CF patients, extracting DNA directly from 14 bronchoscopy or sputum samples. Bacterial 16S ribosomal DNA (rRNA) gene PCR products were amplified from extracted nucleic acids, with analyses by terminal restriction fragment length polymorphism (T-RFLP), length heterogeneity PCR (LH-PCR), and sequencing of individual cloned PCR products to characterize these communities. Using the same loading of PCR products, 12 distinct T-RFLP profiles were identified that had between 3 and 32 T-RFLP bands. Nine distinct LH-PCR profiles were identified containing between one and four bands. T-RFLP bands were detected in certain samples at positions that corresponded to pathogens cultured from CF samples, e.g., Burkholderia cepacia and Haemophilus influenzae. In every sample studied, one T-RFLP band was identified that corresponded to that produced by Pseudomonas aeruginosa. A total of 103 16S rRNA gene clones were examined from five patients. P. aeruginosa was the most commonly identified species (59% of clones). Stenotrophomonas species were also common, with eight other (typically anaerobic) bacterial species identified within the remaining 17 clones. In conclusion, T-RFLP analysis coupled with 16S rRNA gene sequencing is a powerful means of analyzing the composition and diversity of the bacterial community in specimens sampled from CF patients.

Bacterial Infections↗
PubMed2003

Bronchoalveolar lavage cellularity in infants with severe respiratory syncytial virus bronchiolitis.

AIM: To examine over time, the cellular response within the lungs of infants ventilated with respiratory syncytial virus (RSV) bronchiolitis and to compare this response in infants born at term with those born preterm. METHODS: Non-bronchoscopic bronchoalveolar lavage (BAL) samples were taken from 47 infants (24 born at term and 23 born preterm) who were ventilated for RSV positive bronchiolitis and 10 control infants. BAL cellularity and differential cell counts were calculated using standard techniques. RESULTS: Total cellularity in BAL over the first four days of ventilation in infants with RSV bronchiolitis was greater in term infants (median 2.2 (IQR 4.27) x 10(6) cells/ml) compared with preterm infants (0.58 (1.28) x 10(6) cells/ml). The magnitude of the cellular response in preterm infants with bronchiolitis was similar to that in the control group measured on day 1 (0.62 (0.77) x 10(6) cells/ml). BAL cellularity decreased progressively from the time of intubation in term infants, but remained relatively constant in preterm infants up to seven days after intubation. CONCLUSIONS: There are differences in the magnitude and type of pulmonary cellular response in term and preterm infants ventilated with RSV bronchiolitis. The cellular response in term infants with bronchiolitis differs from that in a control group of infants. These differences may reflect variations in cellular recruitment in the lung and/or variations in airway calibre.

Bronchiolitis, Viral↗
PubMed2003

Characterization of rotaviruses causing diarrhoea in Vietnamese children.

Faecal samples from 123 children admitted to the Centre for Tropical Diseases in Ho Chi Minh city, Vietnam, with acute watery diarrhoea were screened by negative-stain electron microscopy for viral enteropathogens. In addition to the 48 children who were found to be infected with rotavirus only, one had both rotavirus and astrovirus, two had adenovirus 40/41, and one had astrovirus only. The rotaviruses were subjected to molecular analysis by electropherotyping, G- and P-genotyping (by reverse-transcriptase PCR), and amplicon sequencing. By use of newly designed PCR primers, all 49 isolates could be G-genotyped and all but one P-genotyped. Novel variants of G1-G1*--were the most commonly detected G-genotype and such variants of P[8]-P[8*]--were the second commonest P-genotype. The P[8*] and G1* amplicons were, respectively, only 92%-93.4% and 88.1%-89% similar to the corresponding sequences from the prototype P[8] G1 rotavirus, Wa. Several unusual P- and G-genotype combinations were detected. Four (8%) of the children investigated were each found to be co-infected with two different rotaviruses. These data add to our knowledge of the continuing evolution and diversity of human rotaviruses, and should help in the rational design of vaccines.

Adenoviridae↗
PubMed2003

Detection of Cryptosporidium amongst diarrhoeic and asymptomatic children in Jeddah, Saudi Arabia.

Between the March and May of 2000, stool specimens were collected from children aged <5 in six pre-school crèches and clinics in the Jeddah area of Saudi Arabia. Sixty-three (25%) of the children had diarrhoeal disease but the other 190 were asymptomatic. When the stool samples were stained and examined for the oocysts of Cryptosporidium spp. and other enteric protozoa, 20 (32%) of the symptomatic children but only nine (4.7%) of the asymptomatic were found to be excreting Cryptosporidium oocysts. Similarly, Cyclospora cayetanensis was found, always as a co-infection with Cryptosporidium sp., in seven (11%) of the children with diarrhoeal disease but only eight (4.2%) of the asymptomatics. One asymptomatic child was found to be co-infected with Isospora belli and Cryptosporidium. Giardia intestinalis and cysts of Entamoeba histolytica/dispar were detected in 18 (29%) and nine (14%) of the children with diarrhoeal disease and in eight (4.2%) and 13 (6.8%) of the asymptomatic children, respectively. This appears to be the first report of Cy. cayetanensis from Saudi Arabia and the highest prevalence of Cryptosporidium infection ever described.

Animals↗
PubMed2003

Molecular epidemiology of endemic ciprofloxacin-resistant Neisseria gonorrhoeae in Liverpool.

Ciprofloxacin-resistant Neisseria gonorrhoeae had been rarely detected on Merseyside and when found was associated with beta-lactamase producing strains, imported from abroad. However, in August 2000, two cases of infection with ciprofloxacin-resistant beta-lactamase-negative strains occurred in sexually unrelated patients with no history of foreign travel. Over the next 18 months a total of 120 patients presented with ciprofloxacin-resistant gonococci, from which 99 patient strains were available for study. Gonococcal DNA was subjected to molecular fingerprinting by polymerase chain reaction amplification followed by Taq1 digestion of their opa genes. Twelve differing opa-types were found, but 79 patients were infected with a single genotype, opa-type 1. The sexual histories of the majority of this group indicated acquisition in Merseyside. This endemic strain was further characterized by having the same amino acid substitutions on gyrA and parC genes. An endemic clone of ciprofloxacin-resistant N. gonorrhoeae has been established on Merseyside necessitating the introduction of ceftriaxone as first-line treatment. Despite the presence of 11 other clones in the city, opa type-1 strains have not yet been displaced, raising the possibility that this strain is endowed with added virulence/endemicity traits or that a number of source patients have not yet been found.

Amino Acid Substitution↗
PubMed2003

Severe meningococcal disease in childhood.

Meningococcal disease remains an important cause of illness in the UK (Commun Dis Rep CDR Suppl 1999; 9: S5), and is the commonest infective cause of death in children outwith the neonatal period. Although most common in children, adults are also affected. Meningococcal vaccines offer long-term protection only against Group C disease, which causes less than half of invasive meningococcal disease (Commun Dis Rep CDR Wkly 1998; 8: 2) in the UK.

Adult↗