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Biomedical subjects

G L Gilbert

Publications and source records attributed to G L Gilbert.

At least 73 records · Page 4Linked to original sources
PubMed1996

Differing antibody responses to Haemophilus influenzae type b after meningitis or epiglottitis.

Two common forms of invasive disease due to Haemophilus influenzae type b (Hib) are epiglottitis and meningitis. It is not known why some children develop epiglottitis and others meningitis. To examine the hypothesis that epiglottitis occurs in children who may have been previously exposed to Hib, and who would therefore exhibit a more vigorous antibody response in convalescence, we measured levels of antibody to Hib capsule in 92 children. Geometric mean convalescent-phase IgG, IgA, IgM and total antibody levels were significantly higher in 45 children with epiglottitis than in 47 with meningitis, even after adjustment for age differences (mean total antibody, 95% confidence intervals: meningitis 0.38, 0.34-0.43; epiglottitis: 2.25, 2.0-2.54 micrograms/ml). However, contrary to previous reports, a poor antibody response was only observed in a minority of children with meningitis; the antibody response of the majority was indistinguishable from that observed in children with epiglottitis.

Acute-Phase Reaction↗
PubMed1996

Genetic characterization of Mycobacterium avium isolates recovered from humans and animals in Australia.

Genetic relationships amongst 115 mainly Australian isolates of Mycobacterium avium were assessed using multilocus enzyme electrophoresis (MEE). The isolates were divided into 58 electrophoretic types (ETs), with a mean genetic diversity of 0.29. Isolates from humans were closely related to but distinct from those cultured from birds, whilst some porcine isolates belonged to the same ETs as certain human isolates. Pulsed field gel electrophoresis (PFGE) was used to differentiate related isolates, and those from birds and some from other animals, including pigs, were distinguished from the human isolates. The results of MEE and PFGE suggested that certain strains of M. avium may be transmitted between birds and pigs, but there was no clear evidence of transmission to humans. The serovar of the M. avium isolates was not obviously related to their ET assignment or their PFGE type.

Animals↗
PubMed1996

Antifungal susceptibility testing using the E test: comparison with the broth macrodilution technique.

The National Committee for Clinical Laboratory Standards reference broth macrodilution method for antifungal susceptibility testing was compared with the E test by testing 86 clinical isolates of Candida spp. and Cryptococcus neoformans. The MIC agreement rates for the two methods for Candida spp. were 73-89% within +/-1 doubling dilution and 87-100% within +/-2 dilutions. For C. neoformans, agreement within +/-1 dilution was > 70% for all the agents tested except fluconazole for which agreement was 35%. Our data support the further evaluation of the E test as an alternative method for antifungal susceptibility testing. However, E test MICs of fluconazole for C. neoformans, particularly C. neoformans var. gattii should be interpreted with caution, as falsely elevated MICs may occur.

Antifungal Agents↗
PubMed1996

Acyclovir for the prevention and treatment of varicella zoster in children, adolescents and pregnancy.

Varicella causes a mild, self-limiting childhood disease that may reactivate years later as shingles. In immunocompromised patients with altered cell mediated immunity, and rarely in healthy individuals, varicella results in a life-threatening infection. The antiviral drug, acyclovir, substantially reduces the mortality and risk of severe disease in these groups of patients. Early commencement of acyclovir is recommended for children with both varicella and altered cell mediated immunity, newborns during the first 2 weeks of life, preterm infants in the neonatal nursery, and severe varicella or shingles (including ocular zoster) in any patient, as well as during pregnancy. Acyclovir may be considered in children with serious cardiopulmonary disease or chronic skin disorders where varicella may exacerbate the underlying disease or increase the risk of secondary bacterial sepsis. Acyclovir, however, is not recommended for healthy individuals without severe disease, as a prophylactic agent against varicella, for asthmatics receiving aerosolized or low-dose oral steroids and/or as treatment of the post-varicella syndromes. When acyclovir is prescribed it should be given intravenously to those with severe disease, those at risk of dissemination and in children younger than 2 years of age.

Acyclovir↗
PubMed1996

Sporadic invasion of cultured epithelial cells by Haemophilus influenzae type b.

While working with an in vitro invasion assay, we observed that Haemophilus influenzae type b occasionally exhibits highly invasive behavior. The phenomenon is not inhibited by colchicine or cytochalasin but is dependent on the presence of supplemental CO2. We propose that sporadic invasiveness may correlate with the unknown events that precede Haemophilus influenzae type b bacteremia.

Bacterial Adhesion↗
PubMed1996

Comparison of cell culture, mouse inoculation, and PCR for detection of Toxoplasma gondii: effects of storage conditions on sensitivity.

The sensitivity of detection of a wild-type strain of Toxoplasma gondii by cell culture, mouse inoculation, and PCR was determined following sample storage under conditions to which clinical specimens may be subjected during transport to the testing laboratory. Sample storage at -20 degrees C significantly decreased the sensitivity of mouse inoculation. The sensitivity of cell culture decreased with sample storage at 4 and -20 degrees C. The sensitivity of PCR was reduced by storage at 4 degrees C for 48 h, freezing, and heating. These findings have implications for the selection of appropriate methods for the direct detection of T. gondii organisms in suboptimally transported clinical samples.

Animals↗
PubMed1995

Prospective study of diarrhoeal outbreaks in child long-daycare centres in western Sydney.

OBJECTIVE: To investigate outbreaks of diarrhoeal illness in children attending long-daycare centres (LDCs), to characterise parasitic, bacterial and viral isolates from the children's faeces and to identify individual and LDC risk factors for diarrhoea. DESIGN: Eleven-month prospective case-control study of diarrhoeal outbreaks among children in LDCs. SUBJECTS: 2368 children attending 35 LDCs in the western Sydney area. MAIN OUTCOME MEASURES: Frequency of diarrhoeal outbreaks, rate of attack and spread to family members; pathogens isolated from stools; and individual and LDC risk factors. RESULTS: The overall incidence of diarrhoeal disease was low (0.28 outbreaks per centre per year and 0.056 outbreak-associated cases per child-year). Attack rates during outbreaks varied widely (4%-55%; mean, 15%), as did secondary spread rates to family members (1%-15%; mean, 9%). Pathogens were isolated from 7% of symptomatic children and 7% of controls; no outbreak was shown to be caused by a recognised pathogen. Children with outbreak-associated diarrhoeal illness were more likely to have suffered vomiting, poor appetite, lack of energy, fever and to have taken antibiotics in the previous week than other children. Hygiene practices varied widely among centres. CONCLUSIONS: We found low incidence and morbidity from diarrhoeal illness in Australian urban LDCs. Diarrhoea in children in LDCs may be caused predominantly by non-infectious factors such as diet and antibiotic exposure. Current hygiene measures in LDCs seem adequate to prevent and contain outbreaks of infectious diarrhoea.

Child↗
PubMed1995

Infectious diseases.

Routine antenatal screening can detect some potentially serious infectious diseases or susceptibility to infection and allow intervention to prevent adverse outcomes. However, screening programmes can only be justified if appropriate criteria are met for the quality of laboratory tests and interventions. For many infections that are associated with adverse maternal or fetal effects, there are no suitable, cost-effective methods of screening or prevention. However, early diagnosis of infection in high-risk women or those with symptoms can allow preventive intervention. Acute febrile illness or other symptoms consistent with infection during pregnancy should be investigated more diligently than in a non-pregnant woman. Early diagnosis of an apparently trivial maternal infection may prevent serious fetal disease. When the diagnosis of maternal infection is made, appropriate action depends on the nature of infection and the stage of pregnancy at which it occurs. The results of serological test should be confirmed, preferably by a reference laboratory, by retesting the original specimen(s) and/or testing further specimens, as appropriate. Management decisions generally should be made in consultation with an infectious disease physician or clinical microbiologist with experience of infectious diseases in pregnancy.

Female↗
PubMed1995

A comparison of chemical dipsticks read visually or by photometry in the routine screening of urine specimens in the clinical microbiology laboratory.

Two different commercially available urine dipsticks were evaluated to determine their usefulness as a screening test for the detection of non-infected urine specimens. The reactions of both dipstick strips were read visually and, in addition, one was read by semi-automated reflectance photometry. 2928 consecutive routine urine specimens received by the microbiology laboratory during normal working hours underwent testing by the conventional method of microscopy and culture and the results were compared with those obtained by dipstick testing. There were poor correlations between microscopy for red and white blood cells and dipstick results for blood and leucocyte esterase respectively. The dipsticks had a low positive predictive value (PPV) in identifying infected urines. In contrast, dipsticks had a very high negative predictive value (NPV) of 98.6-99.5% and correctly identified a significant proportion (about 1/3) of non-infected urines as reported by the conventional method. Introduction of dipstick testing of urine specimens in our hospital has led to significant time saving as dipstick-negative urines are not processed further (except for specific clinical indications) and there has also been a significant decrease (25%) in the number of specimens submitted to the laboratory. Further efficiencies may be obtainable with increased automation.

Adolescent↗
PubMed1995

Mycobacterium ulcerans infection in Australian children: report of eight cases and review.

In the past 25 years, eight patients with presumed or proven Mycobacterium ulcerans infection have been treated at the Royal Children's Hospital, Melbourne, Australia. At least four of these patients had recently been in southeastern Victoria, Australia, a temperate region where the disease was first described and where sporadic infection occurs. Nonspecific clinical manifestations and an indolent course often lead to delayed diagnosis. Surgical excision is the mainstay of treatment and was used for all of the patients; however, for one of the patients, adjunctive heat treatment was limb saving because both antimycobacterial drugs and surgery failed to stop the progression of necrotizing ulceration. We describe this case as well as that of a patient who presented with a rare manifestation of the infection--panniculitis. In addition, we review the microbiology, epidemiology, clinical presentation, pathology, and management of M. ulcerans infection.

Australia↗
PubMed1995

Clinical manifestations and outcome of Haemophilus influenzae type b disease.

OBJECTIVE: To document clinical manifestations, laboratory findings and outcome of childhood Haemophilus influenzae type b (Hib) infections. METHODOLOGY: Medical records of 235 children with Hib disease admitted to hospital during a 2 year period were reviewed; additional information was obtained by questionnaire and follow up 6 weeks after discharge. RESULTS: Three-quarters of patients presented with either meningitis or epiglottitis. Children with epiglottitis were older, had shorter illnesses and were less likely to have had antibiotics before admission than those with meningitis; 38% of the latter had been given some antibiotic therapy, with no apparent effect on the outcome. Fever persisted for 7 days or more in 23% of patients with meningitis. Death from meningitis occurred in 3.8% of patients and was due to fulminating disease. CONCLUSIONS: These data will assist in recognition and appropriate management of Hib disease as the clinical manifestations become less familiar following the introduction of immunization. Specific laboratory diagnosis is required for accurate surveillance, which should be maintained in order to ensure high immunization rates.

Adolescent↗
PubMed1995

A case-control study examining risk factors for invasive Haemophilus influenzae type b disease in Victoria, Australia 1988-90.

OBJECTIVE: To determine whether day-care attendance was a risk factor for Haemophilus influenzae type b (Hib) disease, particularly for epiglottitis. METHODOLOGY: A case-control analysis of risk factors for invasive Hib disease was performed in Victoria, Australia between February 1988 and February 1990 prior to the introduction of immunization for Hib. A total of 210 cases and 367 day surgery hospital controls were enrolled prospectively. Data were collected by questionnaire at the time of admission. RESULTS: Logistic regression analysis showed that risk factors for meningitis were day-care attendance, household crowding and recent illness in a sibling. Risk factors for epiglottitis were day-care attendance and mother's birthplace in Australia or New Zealand. CONCLUSIONS: This study confirms that day-care attendance is a risk factor for Hib epiglottitis as well as meningitis. In addition, the mother's birthplace in Australia or New Zealand is a risk factor for epiglottitis in these data. The reason for this latter observation is unclear.

Case-Control Studies↗
PubMed1995

Prevention of neonatal group B streptococcal sepsis: is routine antenatal screening appropriate.

Four strategies for prevention of early onset neonatal group B streptococcal (GBS) sepsis were considered: A: routine antenatal screening for GBS vaginal carriage at 26-28 weeks' gestation and intrapartum antibiotic prophylaxis for all carriers; B: screening as above and prophylaxis only for carriers with risk factors for sepsis; C: prophylaxis for all women with risk factors; D: as for C plus screening at 37 weeks' gestation and prophylaxis for carriers. The outcomes considered for each option were: the proportion of women given prophylaxis; the risk of anaphylaxis; cases of neonatal GBS sepsis and deaths prevented; costs of screening, prophylaxis and of acute care of remaining cases. Published local and overseas studies of neonatal GBS sepsis, effectiveness of antenatal screening and prophylaxis and estimated costs were evaluated. Any of the proposed strategies can prevent a significant proportion of cases of neonatal GBS sepsis and a strategy for prevention of neonatal group B streptococcal sepsis should be part of routine obstetric practice. Strategy C is simple, effective, inexpensive and avoids unnecessary antibiotic use; it is recommended particularly when antenatal care is provided mainly in community or private practice. Strategy A (using vaginal and rectal swabs for screening) could prevent more cases, but at greater cost which could be justified only if protocols can be properly implemented and monitored.

Australia↗
PubMed1994

Subtyping of Mycobacterium avium complex (MAC) isolates by thin-layer chromatography--distribution of subtypes from patients with AIDS compared with clinically non-significant isolates.

Thin-layer chromatography (TLC) was compared with seroagglutination for subtyping of Mycobacterium avium complex (MAC) bacteria. Seventy-five significant MAC isolates from patients with AIDS were typed by both methods and 36 isolates, judged to be clinically non-significant, were examined by TLC only. Overall, 75% of isolates tested were typable by seroagglutination and 91% by TLC; the results correlated between the two except for minor discrepancies. Serovars 1, 8 and 21 and mixed serovars 1-21 and 1-8-21 were common among isolates from AIDS patients and together represented 83% of isolates compared with only 36% in the non-significant group (odds ratio 8.4; 95% confidence interval 3.4-23.3). This difference remained significant after exclusion of serovar 41 (M. scrofulaceum), which was the commonest isolate (28%) in the non-significant group but was not isolated from patients with AIDS. TLC is useful to supplement seroagglutination for subtyping of MAC. Further study is required to determine whether apparent differences between isolates from patients with AIDS and from other sources reflect differences in virulence or in environmental prevalence of MAC subtypes.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Seroepidemiology of cryptosporidiosis in children in Papua New Guinea and Australia.

Enzyme immunoassays (EIA) were used to measure serum antibodies to Cryptosporidium in four immunocompetent adults with recent proven cryptosporidial infection, 379 healthy children and 73 adult volunteers in Melbourne, Australia, and 205 children in Papua New Guinea (PNG) (47 healthy children; 158 with pneumonia). Antibodies peaked 3-6 weeks after infection and fell to baseline within a few months. A high level (5000 EIA units/ml) or a significant change between paired sera, of IgG or IgM, were taken as evidence of recent infection and found in 24% of PNG children and in 8% of children and 5% of adults in Melbourne. Among PNG children with pneumonia who had high cryptosporidial antibody levels, those with measles (6/8) were significantly more likely (P = 0.002) to have diarrhoea than the remainder (4/28). Symptomatic cryptosporidiosis may be associated with transient immune suppression due to viral infection. This study indicates that serological surveys can contribute to an understanding of the epidemiology of cryptosporidosis.

Adult↗
PubMed1994

Mycobacterium neoaurum infection of a Hickman catheter in an immunosuppressed patient.

Mycobacterium neoaurum is a rapidly growing mycobacterium that has only once before been reported as a cause of bacteremia in an immunocompromised patient. We report on a patient who developed bacteremia after an allogeneic bone marrow transplantation and from whose blood (taken via a Hickman catheter) M. neoaurum was isolated on three separate occasions. There was a clinical response to therapy with ticarcillin/clavulanate and tobramycin, and the organism appeared to be susceptible to the former in vitro. The Hickman catheter was removed because of persistence of the organism in cultures of blood taken from the catheter. M. neoaurum may be a rare cause of infections in immunocompromised patients and should not be dismissed as an environmental contaminant.

Adolescent↗