PubMed Health⌕ Search

Biomedical subjects

J M Robson

Publications and source records attributed to J M Robson.

At least 19 recordsLinked to original sources
PubMed2002

Limited diversity among human isolates of Bartonella henselae.

A study of 59 isolates of Bartonella henselae reveals relatively limited diversity among those of human origin (n = 28). Either of two distinct alleles of both gltA and 16S ribosomal DNA (rDNA) was found in all isolates, with a high level of congruity between 16S and gltA inheritance among proven human pathogens. Human isolates from all over Eastern Australia were most commonly 16S rDNA (Bergmans) type I, with the same gltA allele as the type strain (Houston-1). Comparable feline isolates were more commonly 16S type II, with less congruity of inheritance between 16S and gltA alleles. Previously described arbitrarily primed PCR and EagI-HhaI infrequent restriction site PCR fingerprinting techniques separated Bartonella species effectively but lacked discriminating power within B. henselae. Examination of the 16-23S intergenic spacer region revealed for several strains several point mutations as well as a repeat sequence of unknown significance which is readily detected by HaeIII restriction fragment length polymorphism analysis. The bacteriophage-associated papA gene was present in all isolates. Enterobacterial repetitive intergenic consensus PCR proved to be a useful and robust typing tool and clearly separated human isolates (including imported strains) from the majority of feline isolates. Our data are consistent with published evidence and with previous suggestions of intragenomic rearrangements in the type strain and suggest that human isolates come from a limited subset of B. henselae strains. They strengthen arguments for careful exploration of genotype-phenotype relationships and for the development of a multilocus enzyme electrophoresis and multilocus sequence typing-based approach to the phylogeny of B. henselae.

Animals↗
PubMed2000

Long-term follow-up of Griggs percutaneous tracheostomy with spiral CT and questionnaire.

OBJECTIVE: To assess late complications following percutaneous tracheostomy using the Griggs technique. DESIGN: Observational cohort study SETTING: General ICU of a 700-bed district general hospital in the United Kingdom. PATIENTS: Twenty-five patients who underwent Griggs tracheostomy in the ICU and survived for at least 6 months after decannulation. INTERVENTION: Patients were invited to attend for assessment by questionnaire and for spiral CT of the trachea. RESULTS: Eight patients had moderate tracheal dilatation, two patients were permanently hoarse, nine patients had minor voice changes, no patient had tracheal stenosis, and no patient had a disfiguring scar. CONCLUSION: Following Griggs percutaneous tracheostomy, 8 of 25 patients developed moderate tracheal dilatation, and none developed a tracheal stenosis. The cosmetic result after Griggs tracheostomy is good, but the number of patients with minor voice changes is high. A further investigation of long-term outcome following Griggs tracheostomy is necessary.

Aged↗
PubMed1999

Cat scratch disease diagnosed by polymerase chain reaction in a patient with suspected tuberculous lymphadenitis.

We present a patient diagnosed as having tuberculous lymphadenitis after lymph node biopsy and referred for tuberculous therapy. On review, because of recent cat exposure, she was tested for cat scratch disease (CSD), but serological tests for Bartonella henselae were negative. However, the diagnosis of CSD was confirmed, and tuberculosis excluded, by polymerase chain reaction techniques. This case serves as a reminder that CSD may mimic tuberculosis histologically and that sensitive molecular diagnostic tests are available.

Adult↗
PubMed1999

Cat-scratch disease with paravertebral mass and osteomyelitis.

The case of a 9-year-old girl with cat-scratch disease (CSD) complicated by development of a paravertebral mass and osteomyelitis is presented. Following multiple scratches and inguinal lymphadenopathy, she developed back pain, and imaging demonstrated a paravertebral mass with evidence of osteomyelitis involving vertebra T9. The diagnosis was made on the basis of detection of Bartonella henselae by use of molecular techniques on an aspirate from the vertebral column and supportive serology for infection with B. henselae. Eleven other cases of this unusual manifestation associated with CSD have been reported in the literature and are reviewed. The patient was treated with gentamicin, followed by rifampicin and trimethoprim-sulfamethoxazole, orally and made a favorable recovery over 7 months. This is comparable with other case reports, regardless of the choice of antibiotic therapy. CSD in immunocompetent hosts is not always self-limiting, and tissues beyond the lymph nodes can be involved.

Bartonella henselae↗
PubMed1999

Isolation, identification, and molecular characterization of strains of Photorhabdus luminescens from infected humans in Australia.

We describe the isolation of Photorhabdus (Xenorhabdus) luminescens from four Australian patients: two with multiple skin lesions, one with bacteremia only, and one with disseminated infection. One of the patients had multiple skin lesions following the bite of a spider, while the lesions in the other patient were possibly associated with a spider bite. The source of infection for the remaining two patients is unknown. As a member of the family Enterobacteriaceae, P. luminescens is unusual in that it fails to reduce nitrate and ferments only glucose and mannose. It gives negative reactions for lysine decarboxylase, arginine dihydrolase, and ornithine decarboxylase (Moeller). The species is motile, utilizes citrate, hydrolyzes urea, and usually produces a unique type of annular hemolysis on sheep blood agar plates incubated at 25 degrees C. A weak bioluminescence is the defining characteristic. P. luminescens is an insect pathogen and is symbiotically associated with entomopathogenic nematodes. Its isolation from human clinical specimens has been reported previously from the United States. Restriction fragment length polymorphism-PCR analysis of the 16S rRNA gene demonstrated a high level of similarity among the Australian clinical strains and significant differences between the Australian clinical strains and the U.S. clinical strains. However, numerical analyses of the data suggest that the two groups of clinical strains are more similar to each other than they are to the symbiotic strains found in nematodes. This is the first report of the isolation of P. luminescens from infected humans in Australia and the second report of the isolation of this species from infected humans worldwide.

Aged↗
PubMed1998

Meningitis due to Haemophilus influenzae type f.

OBJECTIVE: To describe a case of Haemophilus influenzae type f (Hif) meningitis occurring in the H. influenzae type b (Hib) vaccine era. RESULTS: Successful treatment of a case of Hif meningitis in a previously vaccinated 3-year-old girl is described. The outcome was complicated by deafness. No underlying immunosuppression was demonstrated. CONCLUSIONS: Despite the great success of Hib vaccines in reducing invasive disease due to H. influenzae, cases of H. influenzae meningitis continue to occur, caused by less common encapsulated serotypes. Whether there will be an increase in the number of these cases in the vaccine era is unknown and infection due to non-b serotypes requires close monitoring.

Child, Preschool↗
PubMed1998

Risk factors for toxicity in elderly patients given aminoglycosides once daily.

OBJECTIVE: To determine the risk factors for aminoglycoside toxicity in the elderly. DESIGN: Prospective observational study. SETTING: Acute care teaching hospital serving predominantly veterans. PARTICIPANTS: Consecutive patients aged 70 years and over receiving aminoglycosides. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirteen (15%) of 88 patients developed aminoglycoside-related nephrotoxicity and 3 (3.4%) developed otovestibular toxicity. Multivariate analysis showed that increasing duration of aminoglycoside therapy was the only factor significantly associated with development of toxicity. Elevated baseline serum creatinine level (p = .02) and use of allopurinol (p = .03) were risk factors specifically for nephrotoxicity. Only 2 (3.9%) of 51 patients receiving aminoglycosides 7 or fewer days developed nephrotoxicity, as compared with 11 (30%) of 37 receiving the drugs for 8 to 14 days and 4 (50%) of 8 treated for more than 14 days. CONCLUSIONS: Although toxicity is common in elderly patients treated with aminoglycosides, limiting the duration of aminoglycoside therapy to less than a week can substantially reduce risk of toxicity.

Aged↗
PubMed1998

Monitoring of serum aminoglycoside levels with once-daily dosing.

There is considerable confusion as to how to monitor serum aminoglycoside levels when using once-daily dosing. At least five methods are in use in Australia. We prospectively assessed 100 consecutive once-daily courses of gentamicin or tobramycin, during which 120 pre-dose and 213 sets of immediate post-dose and six hour post-dose levels were taken. By using the six hour post-dose level we were able to compare dosage recommendations made using methods known as ALADDIN, DOSECALC and the Australian Antibiotic Guidelines nomogram (AAGN). There were statistically significant differences in the doses recommended by each method. When comparing each of the three methods, at least 25% of dosage recommendations differed by more than 80 mg per dose. Although we have not been able to determine the clinical significance of these differences, we are concerned that methods used in dosage adjustment of aminoglycosides differ so widely in their recommendations. Presumably the ALADDIN method, which utilises two post-dose levels to determine an area under aminoglycoside concentration-time curve, gives more accurate pharmacokinetic information than methods which rely on a single level. Comparative cost-effectiveness studies of different methods, although in practice difficult to perform, should be undertaken to resolve the optimal management of patients receiving aminoglycosides once-daily.

Adult↗
PubMed1998

Erysipelothrix rhusiopathiae: an uncommon but ever present zoonosis.

Erysipelothrix rhusiopathiae is an important animal pathogen with a worldwide distribution, yet this zoonotic infection is rarely reported in humans. Three cases of E. rhusiopathiae infection, which illustrate the varied clinical presentations of this pathogen in humans, are presented together with the pathological findings and treatment regimens.

Adult↗
PubMed1997

Application of polymerase chain reaction assay in the diagnosis of orbital granuloma complicating atypical oculoglandular cat scratch disease.

BACKGROUND: Parinaud oculoglandular syndrome is uncommon. Most cases are caused by cat scratch disease (CSD), recently discovered to be associated with the pathogen Bartonella henselae. Before isolation of the micro-organism, diagnosis relied on the presence of characteristic clinical features. However, atypical cases could cause diagnostic problems. With the development of an indirect fluorescent antibody test and polymerase chain reaction (PCR) assay, oculoglandular CSD can be diagnosed readily. METHODS: The authors report a case of atypical Parinaud oculoglandular syndrome in a 51-year-old woman who presented with an inferior conjunctival forniceal mass extending into anterior orbital tissues. Blood and operative tissue specimens were obtained for routine screening and histopathologic analysis but more specifically for serologic analysis, culture, and PCR assay for B. henselae. Computed tomography was performed to delineate the mass. RESULTS: Cultures for B. henselae were negative. Initial serologic analysis demonstrated a low IgG response without detectable IgM, but 1 month later had undergone a fourfold rise in IgG, again without detectable IgM. Histopathologic analysis showed a nonspecific necrotizing granulomatous inflammation consistent with but not diagnostic of CSD. Polymerase chain reaction assay for B. henselae was strongly positive. Computed tomographic scan showed a preseptal and anterior orbital inflammatory process. CONCLUSIONS: Cat scratch disease due to B. henselae should be suspected in patients with atypical conjunctival inflammation associated with regional lymphadenopathy. PCR assay is extremely useful in establishing the diagnosis. The PCR assay offers the additional advantage of early diagnosis because the test is positive early in the disease. Antibiotic therapy remains controversial. In this case, surgical excision hastened resolution of the conjunctival inflammation. However, the lymphadenopathy responded poorly to antibiotics.

Bartonella henselae↗
PubMed1997

Bartonella henselae bacteraemia in domestic cats from Auckland.

Bartonella henselae causes most cases of cat scratch disease, a self-limited localised lymphadenopathy illness of humans. Bartonella henselae also causes disseminated cutaneous and visceral disease in immunocompromised people. Cat blood (1-5 ml) collected from cats in the Auckland area was processed and plated on to 5% sheep blood brain heart infusion agar and incubated at 35 degrees C in 5% CO2 for 14 days. Bartonella henselae was identified by colony morphology, Gram's stain, twitching motility, biochemical tests and molecular methods. Eight of 48 cats (17%) had Bartonella bacteraemia. Species-specific probes and biochemical profiles identified all isolates as B. henselae. Infected cats pose a risk to humans they lick, scratch or bite. People should be made aware of the risk cats pose.

Journal Article↗
PubMed1995

Human trichostrongyliasis in Queensland.

Trichostrongylus infection, an uncommonly reported zoonosis in Australia, is common in parts of the world where there is close human contact with herbivorous animals. We report 5 cases diagnosed in our laboratory since 1992. Over this period the laboratory has conducted over 46,000 parasitological examinations on feces. All 5 cases were investigated for fecal parasites following detection of a blood eosinophilia. Two of the 5 cases complained of mild abdominal discomfort and diarrhea. It is likely that all obtained their infection following ingestion of contaminated unwashed vegetables which had been fertilized with animal manure. Four of the cases acquired their infection in Queensland and the fifth may have become infected in rural Victoria. All were treated with pyrantel embonate with resolution of the eosinophilia. Follow up fecal specimens showed no parasites. Patients were instructed on the mode of transmission and advised to thoroughly wash any uncooked vegetables prior to ingestion. In our cases, goats and horses were possibly implicated. No published reports of Trichostrongylus spp. in humans in Australia have occurred since the 1930s and it may be more common in Australia than is recognized. The infection may be missed because patients are asymptomatic or have mild gastrointestinal symptoms or only a blood eosinophilia. Trichostrongylus eggs may also be mistaken for hookworm eggs. It is important therefore to distinguish these infections from hookworm infection as the modes of transmission, management and advice regarding prevention differ.

Adolescent↗
PubMed1993

Brucellosis: re-emergence and changing epidemiology in Queensland.

OBJECTIVE: To define the epidemiological and clinical characteristics of human brucellosis, which is being detected in increasing numbers of patients in Queensland. DESIGN AND SETTING: Thirty-four cases of brucellosis diagnosed according to standard clinical and microbiological criteria were studied either retrospectively or prospectively over a two-year period from October 1989 to October 1991. RESULTS: Cases were assessed by means of standard laboratory investigations and a questionnaire documenting clinical symptoms, occupation and recreational activities, treatment and response, relapse rate and complications. Blood cultures taken from 11 patients were positive for Brucella suis; in three others, Brucella suis was cultured from other sites. In the 12 months before diagnosis, all affected individuals were involved in the killing and slaughter of feral pigs. Most infections occurred in rural Queensland but six were contracted in metropolitan Brisbane from feral pig abattoirs. All patients responded to appropriate antibiotic therapy; the relapse rate was 66% in those treated for less than four weeks. Complications (multiple splenic abscesses, epididymitis, cervical lymphadenitis and septic arthritis) occurred in four patients, who were ill for more than one month before diagnosis. CONCLUSIONS: Brucellosis due to Brucella abortus is a disappearing disease in Australia as a result of effective eradication programs in cattle. However, the disease is re-emerging in Queensland because of recreational and occupational exposure to feral pigs infected with Brucella suis. The population at risk is increasing as the lucrative export industry based on field-shot feral pigs expands.

Acute Disease↗
PubMed1989

Allergic fungal sinusitis presenting as a paranasal sinus tumour.

Allergic fungal rhinosinusitis is a rare complication of atopic upper airways disease which may present initially as an expansive tumour of the paranasal sinuses. This reported case was caused by the rare fungal pathogen Bipolaris hawiiensis and illustrates typical clinical and laboratory features of this disorder. Although the optimum management of allergic fungal sinusitis is controversial, combined therapy with surgical clearance, antifungal agents and corticosteroids produced a favourable outcome.

Adult↗
PubMed1983

Reduction in cell-associated low density lipoprotein in dexamethasone-treated HeLa cells: suggested mechanism.

An earlier study of cholesterol metabolism in HeLa cells has provided evidence for the inhibitory effect of glucocorticoids on de novo cholesterol synthesis. To extend this observation to other regulatory pathways involving cholesterol, we have now determined the effects of dexamethasone on the cell-associated low density lipoprotein (LDL) assumed to represent a normal source of exogenous cholesterol. It was found that HeLa cells internalized LDL by low affinity as well as high affinity saturable processes. Since cell-associated LDL was reduced by dexamethasone to 20-60% of the control value, we have made further attempts to examine the nature of this observation. The kinetics of LDL-cell association and the binding studies performed at 4 C indicated that dexamethasone did not affect the immediate binding of LDL to HeLa cells, whereas 25-hydroxycholesterol, which is known in other cells to inhibit LDL binding by reducing the number of LDL receptors, had the same effect in HeLa cells. The nature of the dexamethasone effect appeared to be related to interference with processing of bound LDL after its internalization. Further evidence that dexamethasone did not affect the initial binding of LDL was provided by the experiments in which chloroquine completely abolished the inhibitory action of dexamethasone.

Chloroquine↗