Search PubMed⌕ Search

Biomedical subjects

S T Chambers

Publications and source records attributed to S T Chambers.

At least 19 recordsLinked to original sources
PubMed2006

Ethanol disinfection of plastic-adherent micro-organisms.

This study investigated the bactericidal effect of ethanol/water (70:30 vol:vol) against plastic-adherent organisms that commonly cause line infections. The experiments were performed in polycarbonate wells and all incubations were at 37 degrees C. Bacteria in broth were inoculated into wells and incubated (16, 40 and 72 h) before washing to remove non-adherent organisms and exposure to ethanol/water. Wells were then re-incubated with broth to detect surviving bacteria. All organisms incubated for 16 h were killed by 1h of exposure to 70% ethanol. After incubation for 40 h, 4h of exposure to ethanol was required to kill two strains of Candida albicans. Likewise, one of three of both Klebsiella pneumoniae and Pseudomonas aeruginosa, incubated for 72 h, showed growth after 1h of exposure to 70% ethanol but not after 4h of exposure. These results suggest that in contrast to log phase organisms, which are killed by ethanol/water solutions in seconds, plastic-adherent organisms are more resistant to the bactericidal activity of ethanol.

Biofilms↗
PubMed2006

Lower limb cellulitis: features associated with length of hospital stay.

AIMS: This study aimed to identify features associated with length of hospital stay (LOHS), length of intravenous antibiotic therapy (LIVAT) and six-week outcomes for patients with lower limb cellulitis, and to test the Eron/Passos classification of cellulitis in the New Zealand system. METHODS: Eighty-five variables were collected prospectively from a cohort of 51 inpatients admitted to Christchurch hospital. The primary end-point for analysis was LOHS. LIVAT and six-week outcomes were secondary end-points. RESULTS: On univariate analysis use of diuretics, living alone, cellulitis acuity, a creatinine concentration of >0.1 mmol/l, poor mobility, pulse >90 bpm, age >70 years, oedema extent, chronic oedema, ulceration, neutrophil count >10x10(9)/l, erythema area >1000 cm2 and haemoglobin concentration less than normal were significantly (P= or <0.05) associated with LOHS. A stay of < or =3 days was associated with less oedema, absence of diuretic use and less acute cellulitis. A stay of >7 days was associated with use of diuretics, living alone, age >70 years, more oedema, erythema area >1000 cm2, haemoglobin less than normal, ulceration, creatinine >0.1 mmol/l and poor mobility. The presence of a discharge was associated with LIVAT. Multivariate analysis accounted for 48% of the variance in LOHS and 16% for LIVAT. Use of diuretics, neutrophil count >10x10(9)/l and oedema score were independently associated with LOHS, with oedema score associated with short stay and diuretic use with long stay. The Eron/Passos system was not helpful so a new scoring system was devised which successfully classified patients into length of stay groups. CONCLUSIONS: The clinical features analysed accounted for half of the variance in LOHS. An important reason may be physician discretion. If so, our scoring system based on these results could be used in a clinical pathway to improve patient care. This tool would need to be evaluated prospectively.

Adolescent↗
PubMed2005

Reduction of exit-site infections of tunnelled intravascular catheters among neutropenic patients by sustained-release chlorhexidine dressings: results from a prospective randomized controlled trial.

Exit-site and tunnel infections of tunnelled central intravascular catheters are a frequent source of morbidity among neutropenic patients and may necessitate catheter removal. They require antimicrobial therapy that increases healthcare costs and is associated with adverse drug reactions. A prospective randomized clinical trial was conducted among adult patients undergoing chemotherapy in a haematology unit. Tunnelled intravascular catheters were randomized to receive the control of a standard dressing regimen as recommended by the British Committee for Standards in Haematology, or to receive the intervention of a sustained-release chlorhexidine dressing. Follow-up data were available in 112 of 114 tunnelled intravascular catheters which were randomized. Exit-site or combined exit-site/tunnel infections occurred in 23 (43%) of 54 catheters in the control group, and five (9%) of 58 catheters in the intervention group [odds ratio (OR) for intervention group compared with control group =0.13, 95% confidence intervals (CI) 0.04-0.37, P<0.001]. More tunnelled intravascular catheters were prematurely removed from the control group than the intervention group for documented infections [20/54 (37%) vs 6/58 (10%), OR=0.20, 95%CI 0.53-0.07]. However, there was no difference in the numbers of tunnelled intravascular catheters removed for all proven and suspected intravascular catheter-related infections [21/54 (39%) vs 19/58 (33%)], or in the time to removal of catheters for any reason other than death or end of treatment for underlying disease. Thus chlorhexidine dressings reduced the incidence of exit-site/tunnel infections of indwelling tunnelled intravascular catheters without prolonging catheter survival in neutropenic patients, and could be considered as part of the routine management of indwelling tunnelled intravascular catheters among neutropenic patients.

Administration, Topical↗
PubMed2005

Diagnosis and management of staphylococcal infections of pacemakers and cardiac defibrillators.

Staphylococcal species, usually Staphylococcus aureus or Staphylococcus epidermidis, account for 70% to 95% of pacemaker and cardiac defibrillator infections. Infection limited to the generator pocket may cause pain, redness and swelling that is often accompanied by drainage or fistula formation. In this instance, the generator should be removed and reimplanted at another site as cure is rare with antimicrobial therapy alone. Infection of the leads usually tracks along the wire to include the endocardial surface and may involve the tricuspid valve and pocket. Clinical manifestations vary from mild chronic non-specific symptoms to septic shock with marked localizing signs. Septic embolization to the lungs is common and may cause cough, chest pain and shortness of breath that may be misdiagnosed. Blood culture and trans-oesophageal echocardiography (TOE) are the most important investigations.TOE has a sensitivity of >90%. Lead infection without vegetations may occur and these infections should be treated as for endocarditis. Antimicrobial therapy is an important part of treatment but lead infections are unlikely to cured unless the device is removed. Vancomycin is suitable as initial antimicrobial therapy as this covers both S. aureus and coagulase-negative staphylococci. Flucloxacillin, dicloxacillin or a first-generation cephalosporin are preferred if the organism is sensitive. The addition of low-dose gentamicin may improve bacterial killing. The duration of antimicrobial therapy and timing of replacement of the device have not been determined but 2 weeks treatment before removal and 2-4 weeks treatment after replacement is commonly administered.

Anti-Bacterial Agents↗
PubMed2005

Diagnosis and management of staphylococcal infections of vascular grafts and stents.

Staphylococcus aureus and coagulase-negative staphylococci are the commonest bacterial causes of both vascular graft and stent infections. Infection may occur either from direct implantation or haematogenous spread, and occurs in less than 1% of aortic grafts, 2% to 5% of inguinal grafts, and rarely in stents. Death or amputation is common following these infections despite aggressive treatment. Infection with S. aureus is usually more acute than with coagulase-negative staphylococci but both cause systemic symptoms. Inguinal infections usually cause localized swelling often with a sinus tract, bleeding or distal embolism. Aortic infections commonly present with abdominal discomfort retroperitoneal infection or a mass from a false aneurysm. Stent infections usually cause pain, swelling, erythema and circulation disturbances of the ipsilateral limb. The most useful investigations are blood cultures and computerized tomography or magnetic resonance imaging. These imaging techniques have a high sensitivity and specificity in advanced graft infections but these are considerably lower in low-grade infections. Persistence of perigraft fluid beyond 3 months after surgery is suspicious of infection. Aggressive antimicrobial therapy is an important part of management but surgery is usually required to cure both graft and stent infections. Where the organisms are susceptible, high-dose beta-lactam therapy (e.g. flucloxacillin, dicloxacillin or a first-generation cephalosporin) plus low-dose gentamicin are recommended initially. Some authorities add rifampicin after 3-5 days treatment, but this is controversial. Antimicrobial therapy can be stopped 4-6 weeks after surgery if arterial stump cultures are negative but should be continued long-term, and perhaps indefinitely, if they are positive.

Anti-Bacterial Agents↗
PubMed2004

Trigonelline is not responsible for the acute increase in plasma homocysteine following ingestion of instant coffee.

OBJECTIVE: To determine whether trigonelline contributes to the effect of coffee on homocysteine (Hcy). DESIGN AND INTERVENTIONS: This was a randomised crossover study. Subjects consumed 50 mg trigonelline, 5 g of instant coffee (approximately 50 mg trigonelline) or water, consumed as a single dose in 100 ml, with 1 week between each treatment. Blood samples were drawn fasting and hourly for 8 h. Urine samples were collected pretreatment and every 2 h for 8 h. SETTING: Christchurch Clinical Studies Trust, Christchurch, New Zealand. SUBJECTS: Eight healthy male subjects. RESULTS: Instant coffee raised plasma Hcy concentrations compared with water (P=0.019) and trigonelline (P=0.037). Plasma Hcy concentrations were not different between water and trigonelline treatments (P=0.789). The change in plasma Hcy concentration was higher (mean+/-s.e.) 4 h (0.7+/-0.2 micromol/l, P=0.006), 5 h (0.7+/-0.2 micromol/l, P=0.013) and 7 h (0.7+/-0.2 micromol/l, P=0.024) following coffee consumption. Urinary glycine betaine excretion was increased by coffee but not by trigonelline. CONCLUSION: Ingestion of instant coffee acutely elevated plasma Hcy; however, trigonelline is not responsible for this rise. SPONSORSHIP: Supported by the Health Research Council, the Canterbury Medical Foundation, the Foundation of Research, Science and Technology.

Adult↗
PubMed2004

Diagnosis of aspergillus peritonitis in a renal dialysis patient by PCR and galactomannan detection.

This report describes the use of the polymerase chain reaction (PCR) and galactomannan detection to detect aspergillus in the continuous ambulatory peritoneal dialysis (CAPD) fluid and blood of a patient with multiple myeloma on CAPD and immunosuppressive treatment. Diagnosis of aspergillosis was initially made by conventional culture of CAPD fluid, but the PCR and galactomannan assays also detected aspergillus DNA and antigen in the blood, respectively. This suggests that the PCR and galactomannan assays, previously suggested as useful in the management of invasive fungal infections in neutropenic haematological patients, may be suitable for application to a broad range of clinical situations and sample types.

Aspergillosis↗
PubMed2001

Maternity care providers' attitudes and practices concerning HIV testing during pregnancy; results of a survey of the Canterbury and upper South Island region.

AIMS: To assess current attitudes and practice toward antenatal human immunodeficiency virus (HIV) risk assessment, HIV testing and barriers towards implementation of these among midwives, general practitioners (GPs) and obstetricians in the upper South Island METHODS: A survey was conducted among maternity care providers by anonymous self-administered questionnaire. Most questions were dichotomous, forced choice or Likert scale format but there were four open- ended questions asking for a written response. RESULTS: The response rate was 57% overall. The main finding was that 275 (66%) of respondents assessed risk of HIV in less than 10% of patients, and 328 (midwives 93, 85%; GP's 226,77%; obstetricians 9,64%) respondents had performed less than three HIV tests in the past twelve months. Most respondents strongly agreed that detection of HIV during pregnancy is beneficial to mother 318 (83%) and to baby 367 (96%) and to mother prior to pregnancy 353 (92%). 202 (52%) supported and 44 (11%) were opposed to an antenatal screening programme in New Zealand. Most knew how to assess risk for HIV saw themselves as having an important role in antenatal HIV testing, and were comfortable performing risk assessment. Multiple reasons for current practices were offered, including perceived reluctance by women to be tested, lack of time, skills, knowledge and support services, and low rates of HIV in the community. CONCLUSIONS: The current policy of routine HIV risk assessment is not working among respondents. A systematic reassessment and implementation of a workable strategy needs to be undertaken in New Zealand.

AIDS Serodiagnosis↗
PubMed2001

Glycine betaine excretion is not directly linked to plasma glucose concentrations in hyperglycaemia.

Diabetes mellitus subjects, type 1 and type 2, have increased glycine betaine excretion compared to normal subjects that correlated with plasma glucose and HbA(1C) concentrations. The current study was undertaken to determine whether elevated glucose concentration directly increases glycine betaine excretion in an animal model. Non-pregnant female Coopworth sheep received an intravenous glucose load (12.5,25 and 50% w/v; rate 200 ml/h) for 6 h followed by a 12 h physiological saline washout (0.9% w/v). Plasma and urine samples were analyzed for glycine betaine and glucose. Urine volumes and osmolality were also measured. Using the non-parametric Kruskal Wallis analysis of variance test we found no difference in glycine betaine excretion between glucose loaded and saline infused control animals (P=0.861). However, a significant negative correlation (r=-0.28, P<0.001) was observed between urine osmolality and glycine betaine excretion independent of treatment. We conclude that acute elevations of plasma glucose concentrations did not result in increased glycine betaine excretion and is therefore unlikely to be directly responsible for elevated glycine betaine excretion observed in diabetes mellitus subjects.

Animals↗
PubMed2001

Dimethylglycine accumulates in uremia and predicts elevated plasma homocysteine concentrations.

BACKGROUND: Hyperhomocysteinemia is a risk factor for atherosclerosis that is common in chronic renal failure (CRF), but its cause is unknown. Homocysteine metabolism is linked to betaine-homocysteine methyl transferase (BHMT), a zinc metalloenzyme that converts glycine betaine (GB) to N,N dimethylglycine (DMG). DMG is a known feedback inhibitor of BHMT. We postulated that DMG might accumulate in CRF and contribute to hyperhomocysteinemia by inhibiting BHMT activity. METHODS: Plasma and urine concentrations of GB and DMG were measured in 33 dialysis patients (15 continuous ambulatory peritoneal dialysis and 18 hemodialysis), 33 patients with CRF, and 33 age-matched controls. Concentrations of fasting plasma total homocysteine (tHcy), red cell and serum folate, vitamins B(6) and B(12), serum zinc, and routine biochemistry were also measured. Groups were compared, and determinants of plasma tHcy were identified by correlations and stepwise linear regression. RESULTS: Plasma DMG increased as renal function declined and was twofold to threefold elevated in dialysis patients. Plasma GB did not differ between groups. The fractional excretion of GB (FE(GB)) was increased tenfold, and FED(MG) was doubled in CRF patients compared with controls. Plasma tHcy correlated positively with plasma DMG, the plasma DMG:GB ratio, plasma creatinine, and FE(GB) and negatively with serum folate, zinc, and plasma GB. In the multiple regression model, only plasma creatinine, plasma DMG, or the DMG:GB ratio was independent predictors of tHcy. CONCLUSIONS: DMG accumulates in CRF and independently predicts plasma tHcy concentrations. These findings suggest that reduced BHMT activity is important in the pathogenesis of hyperhomocysteinemia in CRF.

Adult↗
PubMed2000

Nosocomial pneumonia in adult general medical and surgical patients at Christchurch Hospital.

AIMS: To determine the incidence, microbial cause, and outcome of nosocomial pneumonia in adult general medical and surgical patients at Christchurch Hospital. METHOD: A one-year prospective study of consecutive patients developing nosocomial pneumonia in a university-affiliated hospital. Expanded diagnostic laboratory testing was undertaken to identify the microbial cause of pneumonia. RESULTS: We recruited 126 patients, which represented an incidence of 6.1 per 1,000 admissions. Only 52 (41%) patients submitted sputum that satisfied the cytological screening criteria for testing. A microbial cause was identified in 47 cases (37%): the most common was Legionella spp. (sixteen cases), followed by Influenza A (six cases) and Staphylococcus aureus (four cases). We did not identify an environmental source of the Legionella species. Fourteen patients (11%) died as a consequence of pneumonia and nearly all of these had significant comorbidity. Renal impairment, alcohol excess, and severity of pneumonia were the most powerful predictors of a fatal outcome by univariate analysis. CONCLUSIONS: In most patients we did not identify a microbial cause of pneumonia; when we did, Legionella species were the most common, although this micro-organism has a long incubation period so some subjects may have acquired it before admission. These results guide preventative efforts, diagnostic testing and selection of antimicrobial therapy for nosocomial pneumonia in our hospital.

Adult↗
PubMed2000

Detection of Legionella DNA in peripheral leukocytes, serum, and urine from a patient with pneumonia caused by Legionella dumoffii.

The polymerase chain reaction (PCR) has been used to detect Legionella DNA in respiratory tract, serum, and urine samples from patients with pneumonia. In addition, a preliminary study using a guinea pig model suggested that testing of peripheral leukocytes by PCR may be more sensitive than testing of other samples. We used PCR to detect Legionella DNA in serial peripheral leukocyte (buffy coat), serum, and urine samples from a patient with pneumonia caused by Legionella dumoffii. Legionella DNA was detected in all 3 sample types when first collected. Buffy coat and urine samples remained positive up to 56 days after the onset of symptoms, whereas serum samples were positive from 10 up to 16 days after the onset of symptoms. Sequencing of PCR amplicons indicated the presence of L. dumoffii DNA in positive samples. It appears that buffy coat may be a useful sample to test for Legionella DNA, but further study is required to determine the precise sensitivity and to make comparisons with other sample types.

Aged↗
PubMed2000

Female genital schistosomiasis.

Schistosoma haemtobium infection in travelers from endemic areas is usually asymptomatic, or presents with hematuria. Uncommon manifestations include neurological syndromes, genital dysaesthesias and watery or blood stained semen. This organism also causes disease within all structures of the female genital tract because of communications between pelvic venous complexes, and can occur long after return home. Schistosomiasis may not be suspected, resulting in delays in diagnosis and treatment. We present two cases which illustrate the diverse nature of this condition.

Adult↗
PubMed1999

Legionella, Chlamydia pneumoniae and Mycoplasma infection in patients admitted to Christchurch Hospital with pneumonia.

AIMS: To determine the incidence, clinical features and outcome of community acquired pneumonia caused by Mycoplasma pneumoniae, Legionella species, Coxiella burnetti, Chlamydia pneumoniae and Chlamydia psittaci requiring admission to hospital. METHODS: Over 12 months the clinical findings and severity of pneumonia were recorded prospectively. Sputum, blood, serum and urine samples were collected for diagnostic testing. Management was supervised by the admitting medical team. Subjects were followed-up six weeks after discharge. RESULTS: Two hundred and fifty-five patients met the entry criteria of whom 20 died, including five who had Legionella infection. M pneumoniae (16%) infection was more often of mild/moderate severity (95%), occurred in a younger age group (mean age 31.4 years, p=0.002), with more frequent myalgia and headache. The length of hospital stay was shorter and clearing of chest radiograph and return to normal activity occurred more rapidly in this group of patients. Legionellosis was common as judged by culture and serological testing (26 cases, 11%) and a further 22 cases were identified by polymerase chain reaction. Legionella infection was not distinguishable clinically from other pneumonias. C pneumoniae was uncommon (8 cases, 3%). C burnetti and C psittaci were not identified in this study. CONCLUSIONS: Some cases of pneumonia caused by Mycoplasma pneumoniae can be identified at presentation, however pneumonia due to Legionella is not distinguishable on clinical grounds. Development of molecular diagnostic techniques may enable therapy to be directed against specific organisms earlier in the course of the disease.

Adolescent↗