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Biomedical subjects

A R Mackenzie

Publications and source records attributed to A R Mackenzie.

At least 19 recordsLinked to original sources
PubMed2006

A seroepidemiological study of bovine pestivirus in Queensland beef and dairy herds conducted in 1994/95.

OBJECTIVE: To describe the distribution and prevalence of cattle herds with detectable antibody to bovine pestivirus in Queensland in 1994/95. MATERIALS AND METHODS: The study used 7,838 serum samples collected from 250 herds in Queensland, as part of a structured animal health surveillance program conducted in 1994 and 1995. Samples were collected from female cattle bred on the property. In each herd, 10 to 20 heifers less than two years of age and 10 to 15 older cows were sampled giving a 95% probability of detecting one or more seropositive animals if the seroprevalence was approximately 10% or greater. Sera were analysed for antibodies to bovine pestivirus using a virus neutralisation test. RESULTS: Total cattle numbers in sampled herds varied from 62 to 24,600 head, while total area of properties sampled varied from 50 to 395,400 hectares. Eleven percent of herds contained no seropositive animals among those sampled, and in 38% of herds, all sampled cattle aged one to two years of age were seronegative. There was a trend for larger herds to have one or more animals seropositive for bovine pestivirus (chi-squared for Linear trend = 3.656, p = 0.056). Herds with more than 500 head of cattle were significantly more likely than herds with less than 500 head to contain one or more seropositive animals in any age group (prevalence ratio = 1.12; 95% confidence interval 1.01 - 1.23; p = 0.026). Age specific seroprevalence increased from around 10% in heifers, to between 75% and 85% in cows aged 10 years. The average annual incidence risk for bovine pestivirus infection varied from 0.12 to 0.24 seroconversions per cattle year at risk, and did not vary with age. The overall crude seroprevalence adjusted for herd size was 45%. There was a wide range of seroprevalence recorded for each level of stocking intensity. CONCLUSIONS: This survey provides valuable baseline data on bovine pestivirus infection in Queensland cattle herds.

Animals↗
PubMed2003

Audit of an antibiotic policy and microbiological investigations for treating bacteraemia in a large teaching hospital.

An audit of different approaches to guide empirical therapy in 78 cases of bacteraemia revealed poor utilisation of the antibiotic policy with resulting inadequate (P=0.005) or excessive (P<0.00001) antibiotic treatment and a trend to increased mortality. Eighty-seven percent of blood cultures were positive on Gram-stain within 24 h but streamlined therapy was still judged excessive in 27%. The results show poor utilisation of an up-to-date antibiotic policy but confirm its potential benefits and the ability of traditional culture methods to guide antibiotic therapy in a useful time-scale.

Anti-Bacterial Agents↗
PubMed2003

Increasing incidence of acute hepatitis B virus infection referrals to the Aberdeen Infection Unit: a matter for concern.

OBJECTIVES: To assess the epidemiology and clinical outcomes of acute hepatitis B virus (HBV) infections presenting to a regional Infection Unit over a ten year period--with reference to the issues of injection drug use and strategies aimed at reducing transmission, notably needle exchange and immunisation programmes. METHODS: A retrospective casenote review of all patients with acute HBV managed at the Infection Unit in Aberdeen between 1991-2000. RESULTS: One hundred and nineteen (119) patients with acute HBV infection were managed during the period of review. The annual number of patients increased from a mean of 3.3/year during the years 1991-96 to 46 in 2000. The risk factors associated with HBV infection were being an injection drug user (IDU) in 57 (47.9%), heterosexual sex in 22 (18.5%), sex with an IDU in 4 (3.4%), men who had sex with men in 10 (8.4%), tattooing in 1 (0.8%), a needle stick injury in 1 (0.8%), trauma 1 (0.8%) and unknown in 23 (19.3%). Many of these patients had "dabbled" in drug use. Thirty-one (54.4%) of the IDU patients had previously been hospitalised with drug-related medical problems. Eighteen (31.6%) of the IDUs were receiving methadone at the time of presentation. CONCLUSIONS: There is an epidemic of HBV infection in the Grampian region of Scotland currently. Forty-six (65.7%) of the 70 infected patients diagnosed during 2000 were seen at the Infection Unit. The remainder had mild or asymptomatic disease and were managed in the community. This epidemic has occurred despite extensive use of local needle exchange facilities and might reflect missed opportunities to immunise IDUs against HBV infection. A co-ordinated approach is now in place to immunise IDUs and other high-risk groups, but the use of universal immunisation demands consideration.

Acute Disease↗
PubMed2002

Three years experience of adults admitted to hospital in north-east Scotland with E. coli O157.

UNLABELLED: To describe the epidemiology, clinical features, treatment and outcomes of adults with E. coli O157 infection presenting to Aberdeen Royal Infirmary over a three year period. METHODS: A retrospective casenote review. RESULTS: Thirty-two confirmed cases of E. coli O157 infection were admitted between 1997 and 2000. The median age was 58 years (range 16-93). Ten patients (31%) were from the city of Aberdeen and 22 (69%) from surrounding rural areas. Twenty-seven patients (85%) presented between May and October. The source of infection was unknown or unconfirmed in all cases. Bloody diarrhoea was present in 30 (94%). Leucocytosis was present in 18 (63%) but only four patients (13%) had a fever. Six of the 32 patients (19%) developed Haemolytic-Uraemic Syndrome (HUS) of whom 2 died. Ten patients received antibiotics of whom two developed HUS. Twenty-seven of the 32 (85%) had made a full recovery by time of discharge, three (9%) had impaired renal function and two (6%) died in hospital. CONCLUSION: E. coli O157 infection tends to occur sporadically in rural areas in North East Scotland. It is not usually associated with fever. Infection occurs more commonly in the summer and autumn. HUS complicates infection in almost one fifth of patients.

Adult↗
PubMed2000

High prevalence of iliofemoral venous thrombosis with severe groin infection among injecting drug users in North East Scotland: successful use of low molecular weight heparin with antibiotics.

Injecting drug use, mainly of heroin, currently represents a major public health issue in the North East of Scotland. The recent tendency of the committed injecting drug user to inject into the groin has created novel problems for the Infection Unit. Data are presented on 20 consecutive patients admitted between 1994 and 1999 with iliofemoral venous thromboses, often complicated by severe soft tissue infections and bacteraemia as a result of heroin injection into the femoral vein. Nine had coexistent groin abscesses, four had severe streptococcal soft tissue infection of the right thigh, groin and lower abdomen, and two had coincidental soft tissue infections of the upper limb. Nine were bacteraemic on admission. All of the patients were chronic injecting drug users with a median injection duration of 6.5 years. The 18 patients tested for hepatitis C virus were all seropositive. None of the 14 patients tested was positive for HIV. Seventeen patients were treated with subcutaneous low molecular weight heparin (tinzaparin), three having received intravenous unfractionated heparin initially. The tinzaparin was self administered and given for a median duration of seven weeks. One patient declined to have any treatment. Three months after presentation eight patients were asymptomatic, seven had a persistently swollen leg, and five were lost to follow up. None developed clinically apparent pulmonary embolism after institution of anticoagulant therapy. The management of iliofemoral venous thrombosis in injection drug users is problematic because of poor venous access, non-compliance with prescribed treatment, ongoing injecting behaviour, and coexistent sepsis. It is unlikely that a randomised trial of standard treatment with heparin and warfarin versus low molecular weight heparin alone would be practical in this patient group. These retrospective data indicate that the use of tinzaparin in injecting drug users is feasible and appears to result in satisfactory clinical responses. The possibility of concomitant infection in injecting drug users with venous thrombosis should always be addressed, as it appears to be a common phenomenon. Early drainage of abscesses and antimicrobial chemotherapy, often administered intramuscularly or orally because of lack of peripheral venous access, is central to the appropriate care of these patients.

Abscess↗
PubMed2000

Impact of the oil industry on malaria diagnosis and management in north-east Scotland (1992-99).

In order to assess the current pattern of malaria presenting to the Aberdeen Infection Unit a retrospective casenote review was undertaken of 110 patients admitted with that diagnosis between 1st January 1992 and 31st August 1999. Oil-related work was the reason for travel in 48 (43.6%) of the UK residents, holiday in 35 (31.8%), backpacking in 8 (7.3%) and other work in 5 (4.5%). Sixty-five patients (59.1%) had PL falciparum malaria (pure or mixed), 25 (22.7%) had PL vivax, 6 (5.4%) PL ovale and 3 (2.7%) PL malariae infection. No prophylaxis had been taken by 66% of the 47 UK-based oil workers and by 36% of the other 48 UK residents who had returned from Africa. There is a need for better education of oil workers and holidaymakers travelling to areas endemic for malaria. We are now setting up a travel advisory service in our Unit to address the problem.

Adult↗
PubMed1999

Epidemiology and outcome of HIV infection in North-East Scotland (1985-1997).

OBJECTIVE: to assess the epidemiology of HIV infection in North-East Scotland. METHODS: retrospective casenote review of all HIV-infected patients who have had contact with the Infection Unit in Aberdeen. RESULTS: one hundred and forty-two HIV-infected patients were treated between April 1985 and December 1997. The risk behaviour related to the acquisition of the HIV infection was: 56 (39%) homosexually infected, 45 (32%) heterosexually-infected, 34 (24%) injecting drug users (IDUs), and seven (5%) blood products or not known. Sixteen of the 45 (36%) heterosexually-infected patients were native to Africa and 16 of the 34 (31%) IDUs were prisoners in Peterhead prison at the time of referral. Fifty-two (37%) of the cohort continue to attend the Infection Unit, 41 (29%) have relocated, 40 (28%) have died and nine (6%) have been lost to follow-up. The ratio of heterosexual:homosexual men:IDUs changed significantly between the first 7 years (12:21:25) and the second 6 years (33:35:9) of the review, with significantly more patients being infected through heterosexual contact and fewer infected by IDU in the second period-P<0.001. The median AIDS survival was 17 months. Survival was significantly longer in those patients who took anti-retroviral therapy (median = 20 months) than in the patients who opted not to take anti-retroviral therapy (median = 11 months)-P<0.01. CONCLUSIONS: Although homosexual contact represents the commonest risk group for HIV infection in this region, the number of heterosexually-infected patients has increased significantly in the last 5 years. Temporary residents account for one-third of the HIV-infected population cared for in NE Scotland. Almost half of those lost to follow-up have returned to Africa or been released from prison. The introduction of anti-retroviral therapy has resulted in a dramatic improvement in AIDS survival in our cohort as it has done elsewhere.

Africa↗
PubMed1999

Duration of intravenous therapy and hospital stay according to choice of empirical antimicrobial treatment for community-acquired respiratory infection.

A review of patients admitted to medical wards with respiratory infection was undertaken to look for differences in duration of intravenous (IV) therapy and length of patient stay based on the class of IV antimicrobial used in treatment. Data was analysed from 231 patients with community-acquired respiratory infection who were treated empirically for at least 24 h with either an IV cephalosporin (146 patients) or an IV penicillin or macrolide (85 patients). The severity of illness and indication for IV treatment was similar in each group. Those treated with a cephalosporin received IV therapy for a significantly longer period (mean = 4.44 days, SD = 2.6) than those given a penicillin or macrolide (mean = 3.3 days, SD = 1.8): P < 0.001. Patient stay was significantly longer in the cephalosporin group (mean = 11.6 days, SD = 10.4) than the penicillin/macrolide group (mean = 9.4 days, SD = 6.3): P = 0.04. These differences are most readily accounted for by the absence from the hospital formulary of a third generation oral cephalosporin, a drug that might be regarded as an obvious form of follow-on therapy in patients treated empirically with an injectable cephalosporin.

Anti-Bacterial Agents↗
PubMed1999

Assessment of the efficacy, safety and quality of gentamicin use in Aberdeen Royal Infirmary.

Fifty-five patients who received od gentamicin were studied. The protocol for od gentamicin was followed in 23/55 (48%). Cure rates were 22/23 (96%) when the protocol was followed and 24/32 (75%) when not followed (P = 0.06). Toxicity was more common in those in whom the protocol was not followed (9/32; 28%) than in those in whom it was followed (1/23; 4%) (P< 0.05). The number needed to treat with the protocol to produce one additional cure was 4.84 (95% CI 2.64 to 28.66) and the number needed to treat to prevent one case of toxicity was 3.61 (95% CI 2.16 to 10.99).

Adolescent↗
PubMed1998

The effect of intravenous-to-oral switch guidelines on the use of parenteral antimicrobials in medical wards.

The effect of an intravenous (i.v.)-to-oral switch policy on antibiotic prescribing in general medical wards was examined. Three audits, each of 2 months' duration, were carried out to examine the duration of i.v. therapy and length of patient stay. The first audit (S1) was performed before the introduction of switch guidelines, the second (S2) after guidelines had been placed in patient case-notes and the third (S3) after the guidelines had been introduced into the drug charts. The duration of i.v. therapy was significantly shorter in the S3 group (mean = 3.7 days) than in the S2 or S1 groups (mean 4.4 and 4.35 days, respectively) (P < 0.05). There was no significant difference in the length of patient stay between the three audit periods but the stay was significantly shorter in 81 switched patients (mean duration = 8.9 days) than in matched controls (mean duration = 12.6 days) (P = 0.01). Fewer patients with respiratory infection were treated for > 24 h with i.v. antimicrobials in the S3 audit period (75/549) than in the S2 (85/372) and S1 audits (83/326) (P < 0.01). The introduction of switch guidelines to drug charts reduces the length of i.v. therapy. Switched patients spend less time in hospital than their matched controls.

Administration, Oral↗
PubMed1998

Spinal epidural abscess: the importance of early diagnosis and treatment.

OBJECTIVES: To remind clinicians of the dangers of delayed diagnosis and the importance of early treatment of spinal epidural abscess. METHODS: A review of the literature on spinal epidural abscess and a comparison of the published literature with local experience. RESULTS: Imaging with MRI or CT enables early diagnosis of spinal epidural abcess and optimal therapy is surgical evacuation combined with 6-12 weeks (median 8 weeks) of antimicrobial chemotherapy. Clinical features are fever, pain, and focal neurological signs and may be associated with preceding and pre-existing bone or joint disease. The commonest aetiological organism is S aureus. CONCLUSION: Early diagnosis and appropriate early antimicrobial chemotherapy with surgery is associated with an excellent prognosis.

Abscess↗
PubMed1998

Raw egg ingestion and salmonellosis in body builders.

Four patients with Salmonella enteritidis infection are reported. All were body builders who regularly consumed substantial quantities of raw eggs. They presented with a severe febrile illness and diarrhoea--presumably reflecting a large bacterial inoculum. Advice regarding the potential hazards of raw egg ingestion has been repeatedly issued by the Department of Health--but this report highlights the fact that this practice continues in spite of this. The epidemiology of S. enteritidis infection in relation to raw egg ingestion is discussed.

Adult↗
PubMed1996

Salmonella Dublin infection in Queensland dairy cattle.

OBJECTIVE: To investigate the presence of Salmonella Dublin in Queensland cattle. DESIGN: An epidemiological study using diagnostic laboratory information and farm records. PROCEDURE: Outbreaks of gastroenteritis or pneumonia in calves, and abortions and enteritis in cows were routinely investigated for the presence of salmonellae. Where S Dublin was isolated, attempts were made to gather further epidemiological information. RESULTS: Prior to 1983 only two outbreaks of S Dublin have been recorded in Queensland dairy cattle. In 1983 S Dublin abortions were diagnosed in dairy heifers introduced from southern Australia to south-east Queensland. Sampling indicated that at least 10% of the 500 introduced heifers were faecal excretors of S Dublin. On 3 of the 7 farms from which S Dublin was recorded, infection spread to other cattle that were in contact. From February 1985 to February 1996, 29 outbreaks of S Dublin in cattle occurred on 29 farms (28 in south east Queensland and 1 in north Queensland). Calves were primarily affected. Continuing outbreaks were confirmed on only 4 of these 29 farms. On 15 farms S Dublin infections were associated with the purchase of infected calves or cows, while another farm adjoined 2 previously infected farms. No source of S Dublin was evident for the other 13 farms, where histories were often inadequate. CONCLUSION: There has been a marked increase in S Dublin outbreaks in Queensland dairy cattle since 1983. Introduction of S Dublin carrier and aborting dairy heifers from southern Australia, where S Dublin is not uncommon, was associated with the initial outbreaks.

Animals↗
PubMed1995

Translumbar amputation: the longest survivor--a case update.

BACKGROUND: Translumbar amputation, known also as hemicorporectomy, was first described by Kredel but was not performed until 10 years later in 1960. It appears that 44 such operations have been reported but probably several others remain unpublished. METHODS: The operation has been performed in 44 reported patients over the past 30 years in more or less the same fashion. Most have been done as a one-stage procedure, but the author favors laparotomy and maturation of urinary and fecal diversions before doing the amputation about two weeks later. RESULTS: Overhydration caused the death of the first three patients. This problem was avoided in the Memorial Sloan-Kettering patients by careful monitoring of central venous pressure. There were no operative deaths, but 8 of the 44 patients died within a month. Survival of cancer patients has not been good, but those with benign lesions have survived fairly well. CONCLUSION: This case is remarkable in that, despite a rapidly advancing cancer of the bladder, the patient lived for over 28 years. It is gratifying to see that other surgeons and patients have not abandoned this most radical of all operations when no other therapy can preserve life.

Amputation, Surgical↗
PubMed1990

P300 and smooth eye pursuit: concordance of abnormalities and relation to clinical features in DSM-III schizophrenia.

Twenty-five DSM-III-diagnosed schizophrenics and 37 normal and age-matched controls were examined using an oddball paradigm for the generation of P300 and smooth eye-pursuit tasks. Results were compared between groups and related to clinical characteristics, including a family history of psychiatric illness. Group differences were found for P300 amplitudes, latencies and eye-tracking. A family history of psychiatric illness was associated with normal eye-tracking in patients. Small P300 amplitudes alone and in combination with long P300 latencies were associated with a family history in controls.

Adult↗
PubMed1990

Disease of geese caused by a new herpesvirus.

A goose flock farmed outdoors in south-eastern Queensland suffered an outbreak of peracute disease with high death rate (97%). Small button ulcers and large plaques overlying lymphocyte aggregates were present on the mucosa of the small intestine of affected birds. Small white foci of necrosis and focal haemorrhages were seen in the livers. Numerous intranuclear inclusion bodies were observed microscopically in hepatocytes and a herpesvirus which grew rapidly in chicken kidney cells was isolated from tissues. Duck virus enteritis (DVE) was suspected but DVE antiserums failed to neutralise the virus. Further serological studies with a limited range of known avian herpesviruses have failed to identify the virus. Experimental transmission resulted in high mortality in geese (100%), lower mortality in ducklings and nil mortality in chickens. Surveillance studies showed no evidence of infection in domestic and wild birds beyond the original farm and the infection appears not to have been established in the area. Wild ducks, which were frequent visitors to the farm dam, were considered the most likely source of the infection.

Animals↗