A survey of ewe mortality on the Central Tablelands of New South Wales in 2010, a year of above-average rainfall

BACKGROUND

Sheep producers reported elevated ewe mortality following a wetter-than-average season on the tablelands of New South Wales in 2010. We conducted a survey of local producers to determine the extent and cause of ewe losses, as well as associated risk factors.

METHODS

A questionnaire was designed and posted to sheep producers running at least 1000 sheep. Data from questionnaires were analysed using linear mixed models to identify risk factors associated with ewe mortality. Data on the likely causes of deaths, particularly those associated with foot abscess, were analysed by ordinal generalised linear mixed models to determine the most prevalent causes of ewe death.

RESULTS

The mean annual ewe mortality was 5.4% (range 0.1%-28.6%). Higher mortality was associated with older ewes and lambing in paddocks with longer pastures. The two most important causes of ewe death reported by farmers were 'died during lambing' and 'foot abscess'. Mortality due to foot abscess was more commonly reported in adult ewes than maiden ewes (odds ratio and 95% confidence interval: 5.61; 3.52, 8.94), when lambing on pasture longer than 5 cm than ≤5 cm (2.96; 1.54, 5.70) and when lambing in spring than in autumn (4.87; 1.36, 17.41).

CONCLUSIONS

The level of ewe mortality observed was at the upper end of that reported previously in Australia. Risk factor analysis suggested that, in wet years, losses due to foot abscess could be reduced by lambing older heavier ewes in autumn on pasture swards less than 5 cm high.

An observational study of direct oral anticoagulant awareness indicating inadequate recognition with potential for patient harm

Essentials Ignorance of direct oral anticoagulants' effects on coagulation tests may be a safety issue. An electronic questionnaire was sent to prescribers in NHS Grampian with 143 respondents. We found widespread evidence of inappropriate interpretation of the clinical scenarios given. The study suggests potential for patient harm due to lack of knowledge and education is required.

SUMMARY

Background Lack of awareness of the nature of the direct oral anticoagulants (DOACs) combined with the poor correlation between routine coagulation test prolongation and the activity of these drugs represents a potential for patient harm. Objectives To establish the level of awareness of the different DOACs, and to assess whether prescribers were able to recognize the state of anticoagulation in a hypothetical patient. Methods and results An electronic questionnaire was sent by email to prescribers in our health board. Among 143 respondents, we found significant differences in awareness of the currently licensed drugs. Of the respondents, 88%, 80% and 50%, respectively, recognized rivaroxaban, dabigatran, and apixaban. When provided with a routine clinical situation, only 13.5%, 17.5% and 16.8%, respectively, recognized that the hypothetical patient was anticoagulated, and only 55-58% recognized that it was unsafe to proceed with an invasive procedure. Conclusion These results indicate a significant risk for patient harm related to lack of knowledge about this new group of frequently used drugs, and indicate that additional education and training on this subject are required.

Inter-examiner reliability when using the Objective Structured Practical Examination (OSPE) mark sheet for physiotherapy practical

The Objective Structured Practical Examination (OSPE) format is used during practical examinations as part of the physiotherapy undergraduate curriculum at the University of the Witwatersrand. Various factors influence inter-examiner reliability and investigating the inter-examiner reliability when using the OSPE can lead to improvement of the examination process. The aim of this study was to establish inter-examiner reliability when using the OSPE mark sheet. Methods: Twelve examiners participated in this study. Thirty-three second year PT students were examined at six stations and by two examiners at each station. The Spearman’s correlation test was used to establish inter-examiner reliability. Results: The general inter-examiner reliability of the OSPE mark sheet was high. There was a high correlation between examiners who had the same level of experience (r=0.79 to r=0.93; p<0.001). The background knowledge section of the OSPE mark sheet showed the greatest inter-examiner reliability (r=0.75 to r=0.91; p<0.001). Discussion: In general, a high inter-examiner reliability was found. Examiners with the same level of experience seemed to generally have better inter-examiner reliability when using the OSPE mark sheet. Furthermore, a well-described, operationalised list of micro-skills also improved inter-examiner reliability. Conclusion: The OSPE mark sheet aids inter-examiner reliability. The use of this method of examination should be encouraged.

Managing the weaning transition of Merino lambs by promoting positive growth rates and increasing survival – is yard weaning a viable option?

The effectiveness of yard weaning to manage the weaning transition period for Merino sheep was investigated on three commercial properties in the New South Wales Central Tablelands. Three experiments were conducted, Experiment 1 investigated the duration of yard weaning, Experiment 2 compared two alternative rations provided to yard-weaned animals, while Experiment 3 compared yard weaning with paddock weaning. The ‘Control’ for each of the three experiments was each producers’ normal paddock-weaning strategy with comparisons based on post-weaning growth rates and weaner survival. Liveweights were recorded at weaning and at 15, 50 and 180 days post-weaning. Growth rates were calculated from liveweight measurements. Survival was determined by the continuing presence of an individual animal at subsequent measurements. Compared with the paddock-weaned Control group, variable responses in liveweight, growth rates and weaner survival to 50 and 180 days post-weaning occurred in the three experiments. Yard weaning was not superior to any of the producers’ normal paddock-weaning practices, however, favourable seasonal conditions in early 2010 prompted high growth rates in the paddock-weaned Control animals relative to those achieved by the yard-weaned animals. Further research is required to determine the optimum duration of confinement and ration (including composition and method of delivery). This work should include comparisons of the behaviour of paddock- and yard-weaned animals and model production benefits versus economic costs for a range of production systems and market scenarios.

Prevalence of chronic viral hepatitis in people of south Asian ethnicity living in England: the prevalence cannot necessarily be predicted from the prevalence in the country of origin

The prevalence of hepatitis B and hepatitis C in immigrant communities is unknown. Immigrants from south Asia are common in England and elsewhere, and the burden of viral hepatitis in these communities is unknown. We aimed to determine the prevalence of viral hepatitis in immigrants from south Asia living in England, and we therefore undertook a community-based testing project in such people at five sites in England. A total of 4998 people attending community centres were screened for viral hepatitis using oral fluid testing. The overall prevalence of anti-hepatitis C virus (HCV) in people of south Asian origin was 1.6% but varied by country of birth being 0.4%, 0.2%, 0.6% and 2.7% in people of this ethnic group born in the UK, India, Bangladesh and Pakistan, respectively. The prevalence of hepatitis B surface antigen was 1.2%-0.2%, 0.1%, 1.5% and 1.8% in people of this ethnic group born in the UK, India, Bangladesh and Pakistan, respectively. Analysis of risk factors for HCV infection shows that people from the Pakistani Punjab and those who have immigrated recently are at increased risk of infection. Our study suggests that migrants from Pakistan are at highest risk of viral hepatitis, with those from India at low risk. As prevalence varies both by country and region of origin and over time, the prevalence in migrant communities living in western countries cannot be easily predicted from studies in the country of origin.

High Merino weaner survival rates are a function of weaning weight and positive post-weaning growth rates

Survival and subsequent productivity of Merino ewe weaners (weaned in 2006 and 2007, respectively) on commercial properties in the New South Wales Central Tablelands were monitored through routine liveweight measurement until weaning of their own progeny from their maiden joining. Growth rates were calculated from the regular liveweight measurements with survival determined by the continuing presence of an individual animal at subsequent measurements. This study demonstrates that high weaner survival rates are a function of both weaning weight and post-weaning growth rates. Importantly, it indicates that low post-weaning growth rates can negate the survival benefit conferred by a high weaning weight such that weaners who were unable to sustain positive post-weaning growth rates were at high risk of death. Furthermore, classification of weaners into liveweight profile groups based on their weaning weight and post-weaning growth rates identified another group of weaners that are also at high risk of death. These weaners (14% of the mob) had above average weaning weights but low post-weaning growth rates and a mortality rate nearly 1.5 times that of the lightest cohort of weaners. High weaner survival rates about the 95% industry benchmark are possible if weaners show positive growth rates post weaning. Weaning weight continues to have a residual influence on the subsequent productivity of ewe weaners until they wean their first lambs. Maiden ewes that were heavier at weaning tend to have higher scanning percentages and are more likely to successfully rear their progeny to marking than their lighter weight counterparts. This finding should be taken into account when economic analyses of the benefits of alternative management strategies to promote weaner survival are undertaken.

Higher weaning weight improves postweaning growth and survival in young Merino sheep

Two monitoring projects were conducted to investigate weaner mortality in commercial Merino flocks in the Yass and the Central Tablelands Rural Lands Protection Boards located in the Southern Tablelands agricultural region of New South Wales. The projects were conducted in Yass in 2005 and in the Central Tablelands in 2006. A random sample of weaners from four flocks in the Yass board and 11 flocks in the Central Tablelands board were regularly weighed, growth rates were calculated after weaning and survival was determined by the continuing presence of an individual weaner at subsequent weighing activities. Weaning weight was the most important factor in determining postweaning liveweight, growth rates and survival with the significant impact of weaning weight on liveweight persisting for up to 6 months after weaning. Despite the lightest weaners being capable of considerable compensatory growth given sufficient postweaning nutrition, the lightest 25% of weaners were more than twice as likely to die as heavier weaners. A focus on ewe nutrition and parasite control during late pregnancy and lactation will allow Merino producers to achieve higher weaning weights that will set their weaners up for strong postweaning growth with a decreased likelihood of mortality.

Non-tuberculous mycobacteria: patterns of isolation. A multi-country retrospective survey

OBJECTIVE

To collect data on non-tuberculous mycobacteria (NTM) isolated from clinical laboratories in different countries to establish: 1) whether the isolation of NTM was increasing, 2) which species were increasing, and 3) whether there was any pattern of geographical distribution.

DESIGN

In 1996, the Working Group of the Bacteriology and Immunology Section of the International Union Against Tuberculosis and Lung Disease contacted 50 laboratories in different countries for the necessary information.

RESULTS

The number of patients reported with NTM was 36099 from 14 countries. Mycobacterium avium complex, M. gordonae, M. xenopi, M. kansasii and M. fortuitum were the five species most frequently isolated. There was a significant upward trend for M. avium complex and M. xenopi. Pigmented mycobacteria predominated in Belgium, the Czech Republic and the Mediterranean coast of Spain. Non-chromogenic mycobacteria were found to be predominant in the area of the Atlantic coast of Brazil and in Turkey, the United Kingdom, Finland and Denmark.

CONCLUSIONS

There was an increase in the number of NTM isolated from clinical samples of patients. Isolation of the most frequent species is constantly changing in most of the geographical areas, and newer species are emerging due to better diagnostic techniques to detect and identify NTM.

Analysis of multidrug-resistant Mycobacterium bovis from three clinical samples from Scotland

OBJECTIVE

To determine whether multidrug-resistant (MDR) strains of Mycobacterium bovis isolated from patients in Scotland were genotypically related.

DESIGN

Genotypes of MDR strains were determined using three molecular fingerprinting techniques: pulsed-field gel electrophoresis (PFGE), spoligotyping and restriction fragment length polymorphism (RFLP). PFGE profiles were also obtained for all medical and veterinary isolates occurring in Scotland in 1997-1998.

RESULTS

MDR strains showed individual Dra I PFGE profiles. Case III/98 had a profile represented in both veterinary and medical populations, Case I/94 had a profile observed in medical but not veterinary isolates, and Case II/98 had a profile unique to this study. Afl II PFGE discriminated the resistant strains. Spoligotyping grouped Cases I/94 and II/98 (ST-134). Case III/98 had a spoligotype ST-140, which is commonly observed in veterinary isolates. Similarly, DRr-RFLP analysis grouped cases I/94 and II/98, whereas Case III/98 had a common veterinary profile. DRX(PGRS) RFLP gave three unique profiles.

CONCLUSION

Three resistant strains were discriminated by PFGE and DRX(PGRS) RFLP, indicating that the three strains are not related in an epidemiologically relevant time scale. However, Cases I/94 and II/98 were more closely linked by spoligotyping and DRr-RFLP data. PFGE and DRr-RFLP linked Case III/98 profiles to the most common veterinary isolate.

The efficacy of the heat killing of Mycobacterium tuberculosis

There is concern that current procedures for the heat inactivation of Mycobacterium tuberculosis may not be adequate. This raises serious safety issues for laboratory staff performing molecular investigations such as IS6110 restriction fragment length polymorphism typing. This paper confirms that the protocol of van Embden et al, as performed routinely in this laboratory, is safe and effective for the heat inactivation of M tuberculosis. This procedure involves complete immersion of a tube containing a suspension of one loopfull of growth in a water bath at 80 degrees C for 20 minutes. Seventy four isolates were included in this investigation. Despite prolonged incubation for 20 weeks, none of the heat killed M tuberculosis suspensions produced visible colonies or gave a positive growth signal from liquid culture. This method did not affect the integrity of the DNA for subsequent molecular investigations.

A national study of clinical and laboratory factors affecting the survival of patients with multiple drug resistant tuberculosis in the UK

BACKGROUND

This study aimed to describe the clinical, microbiological, molecular epidemiology and treatment of multidrug resistant tuberculosis (MDRTB) cases in the UK and to determine factors associated with survival.

METHODS

Ninety MDRTB cases were identified from 1 January 1996 to 30 June 1997; 69 were DNA fingerprinted. Date of diagnosis was determined and data were collated on key demographic factors, clinical, radiological and treatment details. Variables associated with survival were included in a Cox proportional hazards model.

RESULTS

Most of the patients (72.4%) were male, born outside the UK (57.1%), were sputum smear positive (82.2%), and had entered the UK more than 5 years previously (61.9%). Thirty eight of 78 cases (48.7%) had prior TB. Sufficient data on 82 patients were available for survival analysis; 20/27 (74.1%) known to be dead at the end of the observation period had died of tuberculosis. Median survival time overall was 1379 days (95% CI 1336 to 2515) or 3.78 (95% CI 3.66 to 6.89) years (858 days (95% CI 530 to 2515) in immunocompromised individuals (n=32) and 1554 (95% CI 1336 to 2066) days in immunocompetent cases (n=48)). Median survival in patients treated with three drugs to which the bacterium was susceptible on in vitro testing (n=62) was 2066 days (95% CI 1336 to 2515) or 5.66 years, whereas in those not so treated (n=13) survival was 599 days (95% CI 190 to 969) or 1.64 years.

CONCLUSIONS

Immunocompromised status, failure to culture the bacterium in 30 days or to apply appropriate three drug treatment, and age were significant factors in mortality. An immunocompromised patient was nearly nine times more likely to die, while application of appropriate treatment reduced the risk (risk ratio 0.06). Increasing age was associated with increasing risk of death (risk ratio 2.079; 95% CI 1.269 to 3.402)-that is, for every 10 year increase in age the risk almost doubled. Overall survival was lower than that reported in previous studies.

Antibiotic resistant tuberculosis in the United Kingdom: 1993-1999

BACKGROUND

The re-emergence of tuberculosis as a global health problem over the past two decades, accompanied by an increase in tuberculosis drug resistance, prompted the development of a comprehensive national surveillance system for tuberculosis drug resistance in 1993.

METHODS

The UK Mycobacterial Resistance Network (Mycobnet), which includes all mycobacterial reference and regional laboratories in the UK, collects a minimum dataset on all individuals from whom an initial isolate of Mycobacterium tuberculosis complex has been isolated and submitted by source hospital laboratories. Data sought include susceptibility to first line antibiotics, demographic, geographical, and risk factor information.

RESULTS

There were 25 217 reports of initial isolates of M tuberculosis complex in the UK between 1993 and 1999. All were tested for sensitivity to isoniazid, rifampicin, and ethambutol and 12 692 of the isolates were also tested for sensitivity to pyrazinamide and streptomycin. A total of 1523 (6.1%) isolates were resistant to one or more drugs, 1397 isolates (5.6%) were resistant to isoniazid with or without resistance to other drugs, and 299 (1.2%) were multidrug resistant. Although the numbers of drug resistant isolates increased over the period, the proportions remained little changed. Certain groups of people were at a higher risk of acquiring drug resistant tuberculosis including younger men, residents of London, foreign born subjects, patients with a previous history of tuberculosis and those infected with HIV.

CONCLUSION

Although the proportion of drug resistant tuberculosis cases appears to be stable in the UK at present, more than one in 20 patients has drug resistant disease at diagnosis and more than one in 100 has multidrug resistant disease. Tuberculosis control measures should be strengthened to minimise the emergence of drug resistance through rapid diagnosis, rapid identification of drug resistance, supervised treatment, and maintenance of comprehensive surveillance.

Molecular epidemiology of Mycobacterium malmoense infections in Scotland

Clinical isolates of Mycobacterium malmoense collected over 5 years from patients across Scotland with a variety of diseases have been characterized by pulsed-field gel electrophoresis (PFGE), ribotyping, and 16S ribosomal DNA gene sequencing. Results indicate that this species harbors little genetic diversity and that the different strain types that were identified by PFGE showed no correlation with geographical origin or date of isolation.

Molecular evidence for independent occurrence of IS6110 insertions at the same sites of the genome of Mycobacterium tuberculosis in different clinical isolates

Several characteristics of Mycobacterium tuberculosis (e.g., conserved genome and low growth rate) have severely restricted the study of the microorganism. The discovery of IS6110 raised hopes of overcoming these obstacles. However, our knowledge of this IS element is relatively limited; even its two basic characteristics (transposition mechanism and target site selection) are far from well understood. In this study, IS6110 insertions in ipl loci (iplA and iplB) in two collections of clinical isolates of M. tuberculosis from different geographic locations, one from Scotland and the other from Thailand, were investigated. Five different IS6110 insertions in the loci were identified: ipl-4::IS6110, ipl-5::IS6110, ipl-11::IS6110, ipl-12::IS6110, and ipl-13::IS6110. An attempt to establish the phylogenetic relationship of the isolates containing these insertions was unsuccessful, suggesting that some of these insertions may have arisen from more than one event. This possibility is further supported by the observation that IS6110 copies existed in the same site but with different orientations in different isolates, and the insertion site of ipl-1::IS6110 harbored IS6110 copies in both iplA and iplB in different strains. All these suggest the independent occurrence of IS6110 insertions at the same sites of the genome of M. tuberculosis in different clinical isolates. The implications of this finding are discussed.

Comparison of three isolation systems for the culture of mycobacteria from respiratory and non-respiratory samples

AIMS

To compare the recovery of mycobacteria from clinical samples using the MB/BacT rapid culture system with that obtained using egg medium or the Bactec radiometric method.

METHODS

The three methods were compared using 681 clinical samples (462 respiratory and 219 non-respiratory samples) and eight external quality control strains. Culture media were incubated at 35-37 degrees C for six weeks in the MB/BacT system and for 12 weeks in the Bactec system and on egg medium. Solid media were examined macroscopically once a week and the Bactec vials were read six times in the first two weeks, and then weekly for the next 10 weeks (a growth index > 50 indicated a positive vial). The MB/BacT system positive vials were unloaded from the machine as soon as possible after detection. Confirmation of growth for all systems was by Ziehl-Neelson stained smears. Isolates were identified by a combination of phenotypic and molecular methods.

RESULTS

Of the 681 clinical samples, 59 (8.7%) were positive on culture, including 23 strains of Mycobacterium tuberculosis. None of the three systems recovered all of the isolates, but each recovered mycobacteria not detected by either of the other two systems. After six weeks incubation, isolation rates were 87%, 78%, and 90%, and mean times to detection were 13, 19, and nine days for the MB/BacT, egg medium, and Bactec systems, respectively. Although the MB/BacT system was slightly slower than the Bactec system, the biomass was greater, allowing earlier use of molecular probes and earlier inoculation of susceptibility tests.

CONCLUSIONS

The MB/BacT system provides comparable performance to the Bactec radiometric system, without the problems of disposal of radioactive waste. Optimal recovery is obtained when culture on egg medium is used in conjunction with a rapid culture system.

A national audit of the laboratory diagnosis of tuberculosis and other mycobacterial diseases within the United Kingdom

In order to audit United Kingdom laboratory diagnostic and reference services including novel molecular methods for tuberculosis, a questionnaire was sent to laboratories submitting specimens to the PHLS Mycobacterium Reference Unit (MRU) and regional centres and to the Scottish Mycobacteria Reference Laboratory (SMRL) in 1996-7. Nationally, 67.2% of laboratories responded. Most UK laboratories were fully or conditionally CPA accredited and take part in the NEQAS proficiency scheme. On average only 3.3% of primary samples submitted for mycobacterial diagnosis in 1995 produced a mycobacterial culture from approximately half as many patients (that is, a mean of 1488 specimens producing 49 isolates from 23 patients). Potentially over 380,000 specimens are processed for mycobacteria in the UK each year. The majority of laboratories use 4% NaOH +/- NALC for specimen decontamination. Culture on solid media was used by most laboratories and 62.9% also use liquid media. Most laboratories incubated cultures for eight weeks. Few laboratories use molecular diagnostic methods. Laboratories were most likely to use molecular methods for diagnosing tuberculous meningitis and for specimens from immunocompromised patients, although usage was strongly influenced by cost. Within England and Wales 43.9% (47/107) and 56% (61/109) of laboratories wanted a rapid service for rifampicin resistance detection in M tuberculosis from immunocompetent and immunocompromised patients, respectively. In regard to a tuberculous meningitis service, 80.5% (43/112) and 84.3% (102/121) of laboratories wanted this service for immunocompetent and immunocompromised patients, respectively. The quality of reference services was rated as "very good"/"good" by 85.6% of respondents nationally. Rapid molecular amplification diagnostic services were established at the PHLS MRU for rifampicin drug resistance detection nationally and for tuberculous meningitis at the MRU.

Molecular evidence for heterogeneity of the multiple-drug-resistant Mycobacterium tuberculosis population in Scotland (1990 to 1997)

Multiple-drug-resistant Mycobacterium tuberculosis (MDR-MTB) has been well studied in hospitals or health care institutions and in human immunodeficiency virus-infected populations. However, the characteristics of MDR-MTB in the community have not been well investigated. An understanding of its prevalence and circulation within the community will help to estimate the problem and optimize the strategies for control and prevention of its development and transmission. In this study, MDR-MTB isolates from Scotland collected between 1990 and 1997 were characterized, along with non-drug-resistant isolates. The results showed that they were genetically diverse, suggesting they were unrelated to each other and had probably evolved independently. Several new alleles of rpoB, katG, and ahpC were identified: rpoB codon 525 (ACC-->AAC; Thr525Asn); katG codon 128 (CGG-->CAG; Arg128Gln) and codon 291 (GCT-->CCT; Ala291Pro); and the ahpC synonymous substitution at codon 6 (ATT-->ATC). One of the MDR-MTB isolates from an Asian patient had an IS6110 restriction fragment length polymorphism pattern very similar to that of the MDR-MTB W strain and had the same drug resistance-related alleles but did not have any epidemiological connection with the W strains. Additionally, a cluster of M. tuberculosis isolates was identified in our collection of 715 clinical isolates; the isolates in this cluster had genetic backgrounds very similar to those of the W strains, one of which had already developed multiple drug resistances. The diverse population of MDR-MTB in Scotland, along with a low incidence of drug-resistant M. tuberculosis, has implications for the control of the organism and prevention of its spread.

Characterization of IS1547, a new member of the IS900 family in the Mycobacterium tuberculosis complex, and its association with IS6110

Unlike classically defined insertion sequence (IS) elements, which are delimited by their inverted terminal repeats, some IS elements do not have inverted terminal repeats. Among this group of atypical IS elements, IS116, IS900, IS901, and IS1110 have been proposed as members of the IS900 family of elements, not only because they do not have inverted terminal repeats but also because they share other features such as homologous transposases and particular insertion sites. In this study, we report a newly identified IS sequence, IS1547, which was first identified in a clinical isolate of Mycobacterium tuberculosis. Its structure, insertion site, and putative transposase all conform with the conventions of the IS900 family, suggesting that it is a new member of this family. IS1547 was detected only in isolates of the M. tuberculosis complex, where it had highly polymorphic restriction fragment length polymorphism patterns, suggesting that it may be a useful genetic marker for identifying isolates of the M. tuberculosis complex and for distinguishing different strains of M. tuberculosis. ipl is a preferential locus for IS6110 insertion where there are eight known different insertion sites for IS6110. Surprisingly, the DNA sequence of ipl is now known to be a part of IS1547, meaning that IS1547 is a preferential site for IS6110 insertion.

IS6110-mediated deletions of wild-type chromosomes of Mycobacterium tuberculosis

The ipl locus is a site for the preferential insertion of IS6110 and has been identified as an insertion sequence, IS1547, in its own right. Various deletions around the ipl locus of clinical isolates of Mycobacterium tuberculosis were identified, and these deletions ranged in length from several hundred base pairs up to several kilobase pairs. The most obvious feature shared by these deletions was the presence of an IS6110 copy at the deletion sites, which suggested two possible mechanisms for their occurrence, IS6110 transposition and homologous recombination. To clarify the mechanism, an investigation was conducted; the results suggest that although deletion transpositionally mediated by IS6110 was a possibility, homologous recombination was a more likely one. The implications of such chromosomal rearrangements for the evolution of M. tuberculosis, for IS6110-mediated mutagenesis, and for the development of genetic tools are discussed. The deletion of genomic DNA in isolates of M. tuberculosis has previously been noted at only a few sites. This study examined the deletional loss of genetic material at a new site and suggests that such losses may occur elsewhere too and may be more prevalent than was previously thought. Distinct from the study of laboratory-induced mutations, the detailed analysis of clinical isolates, in combination with knowledge of their evolutionary relationships to each other, gives us the opportunity to study mutational diversity in isolates that have survived in the human host and therefore offers a different perspective on the importance of particular genetic markers in pathogenesis.

The management of pulmonary tuberculosis in adults notified in Scotland in 1993

The management of pulmonary tuberculosis (TB) in Scotland in 1993 was studied by asking the physicians responsible for all 321 adult cases of the disease notified that year to complete a standardized questionnaire relating to drug treatment and bacteriology. The response rate to the questionnaire was 100%. Isoniazid and rifampicin were used together in initial therapy in 98.4% of cases, while pyrazinamide was prescribed in 90.3% of cases, broadly in keeping with existing treatment guidelines. However, considerable variability was observed both in the drug regimens employed, and in the duration of initial and continuation phases of chemotherapy. Treatment regimens were therefore frequently at variance with published recommendations. Among patients prescribed drug regimens other than those recommended satisfactory completion of therapy was less common. Microbiological confirmation was provided for 84% of cases in which clinical samples were submitted. However, in approximately 11% of cases, no clinical samples were submitted. Closer adherence to existing treatment guidelines and more rigorous pursuit of microbiological confirmation should further improve the overall management of pulmonary TB in Scotland.

Palliative care at home: an audit of cancer deaths in Grampian region

BACKGROUND

Ninety per cent of the last year of life of cancer patients is spent at home. Some studies have suggested that care in this setting is often suboptimal. Information on the standard of palliative care delivered at home by general practitioners (GPs) and their teams is limited, and clarification of the problems faced is needed.

AIM

To audit the home-based palliative care of patients dying of cancer.

METHOD

Matched postal questionnaires were sent to the GPs and nurses of 1086 successive patients dying of cancer in whatever setting in the Grampian region of Scotland some six weeks after the death to establish the professionals' perception of symptom control, communication problems, use of services, and information given to patients and relatives.

RESULTS

Response rates were 88.8% for GPs (964 out of 1086) and 87.1% for nurses (325 out of 375 that were passed on to nurses). Two-thirds of patients received palliative care at home. Pain was poorly controlled in 15.7%, and poor control of other symptoms ranged from 13.8% (nausea and vomiting) to 21% (depression and dyspnoea). Communication difficulties were present in 93.7% of cases, although only 5.2% of these were of a major nature. District nurses were involved in 76.7% of cases and Macmillan nurses in 28.0%. Twenty-six per cent of referrals to district nurses were assessed as being late in the course of the illness. Patients were fully informed about the diagnosis in 66.3% of cases and about the prognosis in 55.4%. General practitioners were more likely to report the presence of communication problems between themselves and the patient (when compared with nurses: 43.9% versus 28.0%), more likely to report that patients were 'not at all informed' about self-help groups (57.5% versus 36.3%), and were less likely to report the involvement of occupational therapists (21.8% versus 39.7%).

CONCLUSIONS

Levels of reporting of poor symptom control by professionals was much lower than levels reported by relatives in other studies, but there was no difference between the reporting of GPs and nurses. However, a number of areas were identified where care could be enhanced by improved teamwork and further education and training in symptom control, as well as in communication, use of services, and information provision.

IS6110 transposition and evolutionary scenario of the direct repeat locus in a group of closely related Mycobacterium tuberculosis strains

In recent years, various polymorphic loci and multicopy insertion elements have been discovered in the Mycobacterium tuberculosis genome, such as the direct repeat (DR) locus, the major polymorphic tandem repeats, the polymorphic GC-rich repetitive sequence, IS6110, and IS1081. These, especially IS6110 and the DR locus, have been widely used as genetic markers to differentiate M. tuberculosis isolates and will continue to be so used, due to the conserved nature of the genome of M. tuberculosis. However, little is known about the processes involved in generating these or of their relative rates of change. Without an understanding of the biological characteristics of these genetic markers, it is difficult to use them to their full extent for understanding the population genetics and epidemiology of M. tuberculosis. To address these points, we identified a cluster of 7 isolates in a collection of 101 clinical isolates and investigated them with various polymorphic genetic markers, which indicated that they were highly related to each other. This cluster provided a model system for the study of IS6110 transposition, evolution at the DR locus, and the effects of these on the determination of evolutionary relationships among M. tuberculosis strains. Our results suggest that IS6110 restriction fragment length polymorphism patterns are useful in grouping closely related isolates together; however, they can be misleading if used for making inferences about the evolutionary relationships between closely related isolates. DNA sequence analysis of the DR loci of these isolates revealed an evolutionary scenario, which, complemented with the information from IS6110, allowed a reconstruction of the evolutionary steps and relationships among these closely related isolates. Loss of the IS6110 copy in the DR locus was noted, and the mechanisms of this loss are discussed.

In-vitro sensitivities and treatment of less common mycobacteria

There are very few new agents available for the treatment of infections due to the less common mycobacteria. There have been very few systematic studies of in-vitro activity and fewer clinical trials. Yet such mycobacteria are an important cause of serious disease and often conventional antimycobacterial agents are unsuitable either because of in-vitro resistance of the pathogen concerned, or toxicity of one of the components of drug regimens. At present, newer macrolides and quinolones offer promise, but there is a need to extend the in-vitro studies already under way of newer agents against Mycobacterium avium and/or Mycobacterium tuberculosis, to the other, less common mycobacteria. The benzoxazinorifampicins, the oxazolidinones and the acridinones may prove to be of clinical value. In addition to more information on the in-vitro activity of newer agents, alone and in combination, based on systematic studies involving larger numbers of mycobacterial strains, we need clearer clinical information to enable therapeutic regimens to be formulated and validated. The British Thoracic Society study is but a first step. There need to be more.

Antimicrobial treatment of fish tank granuloma

Three patients with fish tank granuloma of the hand and forearm are reported. Each patient was treated with antimicrobial regimes which have rarely or never been previously used in this condition. Two patients responded well to treatment, one who received ciprofloxacin plus clarithromycin and another who was given clarithromycin plus ethambutol. The third patient received six different antimicrobial regimes before responding to a combination of rifabutin and ciprofloxacin. Our experience suggests that there now exist a number of effective alternatives to antimicrobials which have been traditionally used in the treatment of cutaneous Mycobacterium marinum infection.

Comparative activity of azithromycin against clinical isolates of mycobacteria

Azithromycin exhibited in-vitro activity against 20 clinical isolates of Mycobacterium avium complex for which the MIC90 was 32 mg/L and 22 clinical isolates of other mycobacteria but showed no activity against 20 isolates of Mycobacterium tuberculosis (MIC90 > 128 mg/L) nor against the single isolate of Mycobacterium marinum tested (MIC 128 mg/L). These results suggest that the drug may prove useful for the prophylaxis and treatment of infections due to non-tuberculous mycobacteria, including M. avium complex in patients with AIDS.

A double-blind comparative study of norfloxacin versus placebo in hospitalised elderly patients with asymptomatic bacteriuria

Patients over the age of 65 years with clear catch specimens of urine containing organisms sensitive to norfloxacin were blindly randomised to receive either norfloxacin in a dose of 400 mg twice daily for 7 days or a placebo for the same period. Urine cultures were repeated immediately prior to treatment, at the end of treatment and at 7 days, 1 month and 3 months after treatment. Physical and mental function were assessed by performing a Crighton Behavioural Rating Scale at the same time intervals. Observations were made on 29 each of subjects on norfloxacin and placebo. The proportions of patients abacteriuric at the end of treatment, 7 days and 3 months post- treatment were 16/24 (66%), 12/24 (50%) and 5/24 (21%) in the norfloxacin group and 10/26 (38%), 8/26 (31%) and 8/25 (32%) in the placebo group. Percentage calculations (and denominators) exclude those patients withdrawn or for whom there were no specimens available at the sampling interval in question. Means and 95% intervals for the Crighton Behaviour Rating Scales initially and at 3 months in subjects on norfloxacin were 18.1 (15.1-20.7) and 19.1 (16.2-21.9) respectively. The same figures for the placebo group were 15.7 (12.6-18.8) and 16.6 (13.7-19.5). It is concluded that a 7 day course of norfloxacin for the treatment of asymptomatic bacteriuria had no effect on the physical and mental function of elderly continuing care patients, and that one explanation for this is that there was a high rate of urinary re-infection.

Scottish national survey of tuberculosis notifications 1993 with special reference to the prevalence of HIV seropositivity

BACKGROUND

The study sought to determine the contribution of HIV seropositivity to the arrest of decline in tuberculosis notifications in Scotland.

METHODS

Survey forms relating to each tuberculosis notification in 1993 were completed by the notifying consultant. Voluntary anonymous HIV testing of tuberculosis cases aged under 65 was requested. Age, sex, ethnic status, country of birth, employment status, occupation, previous tuberculosis, contact status, risk factors for HIV infection, HIV serostatus of cases aged under 65, site, radiological extent, and bacteriological status of tuberculous disease were determined.

RESULTS

Five hundred and seventy four cases of tuberculosis were originally notified, of which 77 (14%) subsequently proved to be non-tuberculous and were therefore denotified. Of the 497 cases 423 (85%) were white and 58 (12%) were from the Indian subcontinent. Eighty five per cent of patients from the Indian subcontinent were aged < 55 years whereas 64% of white patients were aged > 55 years. Pulmonary disease was found in 74%, non-pulmonary in 22%, and combined disease in 4% of patients. Of 242 HIV tests performed, three were positive and five other HIV positive patients were known, giving an HIV positivity rate of 1.6% of all tuberculosis notifications in 1993. Annual notification rates for Scotland were 9.7 per 10(5) before and 8.7 per 10(5) after exclusion of previously treated cases; rates were 8.4 per 10(5) for the white population and 179 per 10(5) for those from the Indian subcontinent.

CONCLUSIONS

The study documents the distribution of tuberculous disease in Scotland by age, sex, site, and ethnic group for the first time. Notification practices, with respect to denotification, need to be improved. Infection with HIV is presently uncommon in cases of tuberculosis in Scotland but continued vigilance is essential.

Haemophilus parainfluenzae: an unusual case of psoas abscess

A case of Haemophilus parainfluenzae psoas abscess in a previously healthy 36-year-old man is reported here. The absence of any bowel pathology indicates that abscess formation occurred secondary to haematogenous spread of the organism.

Disseminated disease due to Mycobacterium avium complex in AIDS

We retrospectively analysed 46 cases of disseminated infection with Mycobacterium avium complex (MAC) within a cohort of 702 HIV-infected patients in Edinburgh. Clinical features were compared with case-matched controls (AIDS cases without disseminated MAC), and survival and progression times were controlled for confounding variables that influence survival. Disseminated MAC was diagnosed antemortem in 18% of AIDS patients, and was the AIDS-defining diagnosis in 6% of all AIDS cases. Concomitant colonization of respiratory and gastrointestinal tracts was common (61% and 48%, respectively). In 58% of cases, CD4+ counts were < 10 cells/mm3 (median 6 cells/mm3). Weight loss, anaemia, leucopenia, and elevated liver transaminases and alkaline phosphatase were significantly more common among cases than controls. Therapy was given in 74%, and not tolerated in 32%. Following AIDS diagnosis, disseminated MAC incidence was 14% at one year, 25% at 2 years and 36% at 3 years. Median survival after disseminated MAC diagnosis was 6 months, with shorter survival in untreated cases. However, overall survival from AIDS diagnosis was not significantly different between patients who did or did not develop disseminated MAC. Disseminated MAC contributes significantly to AIDS morbidity, and its incidence increases with prolonged AIDS survival. Although survival following diagnosis is short, the development of disseminated MAC in AIDS probably does not affect overall survival. In cohorts with a low incidence, an alternative to prophylaxis might be surveillance and early diagnosis.

Why disease due to Mycobacterium tuberculosis is less common than expected in HIV-positive patients in Edinburgh

By December 1993, only five cases of tuberculosis were observed in the 1030 HIV-positive patients in Edinburgh, U.K., although, on the basis of historical tuberculin skin test data, between four and eight new cases of tuberculosis were expected per year. Of 310 HIV-positive patients, none of the 19 (6.1%) who were tuberculin skin test positive had developed tuberculosis after 87 months (average) of follow-up. It is suggested that new or re-infection is a more common cause of tuberculosis in HIV-positive patients than reactivation. Restriction fragment length polymorphism typing of Mycobacterium tuberculosis strains could confirm this hypothesis and support currently suggested additional infection control procedures.

Commercially available versus home produced egg media for isolation of mycobacteria

AIMS

To compare the growth of clinical isolates of mycobacteria on in-house and commercial egg media.

METHODS

Fresh test media were inoculated with dilutions of the test organisms and growth, colonial morphology and microscopic appearance were compared blindly by two observers. The process was repeated after the test media had been stored for three months. The user friendliness of each of the test media was also assessed.

RESULTS

There was no difference in the microscopic appearance of any given mycobacterial species between different media. All of the test media grew the test species, although Mycobacterium bovis required four weeks on BioMerieux media, compared with two weeks on the other media. There was little obvious effect of storage on any of the media, except with M kansasii. Individual species gave characteristic colonial appearances on inhouse media; all of the commercial media gave non-specific colonial appearances that made presumptive identification very difficult. There were clear differences in the user friendliness of different media.

CONCLUSIONS

Although commercially available egg media in general gave good growth of mycobacteria, only in-house media combined good growth with useful colonial features.

Population genetics of Mycobacterium tuberculosis complex in Scotland analysed by pulsed-field gel electrophoresis

The results of typing of 121 strains in the Mycobacterium tuberculosis complex by PFGE are presented. Every isolate from patients in Scotland over a 3-month period for M. tuberculosis and for 1 year for M. bovis were included along with several laboratory strains including those of BCG. The PFGE results suggest that the population structure of all the strains in this complex is distinctly simple with limited genetic diversity and also suggest that M. bovis is not a distinct species.

Non-tuberculous pulmonary infections in Scotland: a cluster in Lothian?

BACKGROUND

A retrospective study was carried out to confirm the clinical impression that, in Lothian, non-tuberculous mycobacterial infections are as common as pulmonary tuberculosis.

METHODS

All pulmonary isolates of Mycobacterium tuberculosis/bovis and non-tuberculous mycobacteria in Scotland from April 1990 to March 1993, and the notes of all patients with M malmoense isolates in Lothian, were reviewed. Information on mycobacterial culture procedures in Scottish laboratories was obtained as part of an audit project.

RESULTS

Of all pulmonary isolates of mycobacteria in Lothian 53% (108/205) were non-tuberculous strains compared with 18% (140/800) for Scotland outside Lothian. Although comparable in population size and laboratory techniques, Lothian (108) had almost twice as many isolates of non-tuberculous mycobacteria as Glasgow (56), but the proportions of M malmoense and M avium intracellulare complex were similar in both areas. Of 41 patients with M malmoense isolates in Lothian 30 (75%) had clinically significant lung disease; only one was HIV positive.

CONCLUSIONS

Non-tuberculous mycobacteria pose an increasing clinical problem in Scotland as a cause of pulmonary disease. There is a cluster of cases with M malmoense infection in Lothian which cannot be attributed to the high local prevalence of HIV.

Pulmonary tuberculosis in overseas students of higher education is increasing in Edinburgh

In Edinburgh in 1991 a relative excess of pulmonary TB cases in the 15-34 year age group was recorded. Five of 17 notifications in this age group were of overseas students of higher education: three aged 21-29 from Central Africa, one 27-year-old Asian and one 26-year-old Western European. One of the African students was seropositive for HIV infection. Disease presented clinically on average 31 months after entry to the U.K. (range 6-48 months). Four students had smear positive disease. Two patients had had normal chest radiographs 1 and 2 years previously on entry to the U.K.; three students had not previously been radiologically screened. We suggest that students from countries with a high prevalence of tuberculosis should be screened on entry to their course of education and that student health services should develop and maintain a high index of suspicion for tuberculosis in these students.

Comparison of techniques for antimicrobial susceptibility testing of mycobacteria

AIMS

To evaluate adenosine triphosphate (ATP) bioluminescence as a rapid technique for antimicrobial susceptibility testing of Mycobacterium spp by comparing it with conventional and radiometric methods, and to assess its potential for use in clinical microbiology laboratories.

METHODS

115 clinical isolates from a wide range of mycobacterial species and four control organisms of known susceptibility were tested against six antimicrobial agents. Minimum inhibitory concentrations (MICs) were determined after 4-6 weeks' incubation on Middlebrook 7H10 agar. Susceptibility was also determined radiometrically using a Bactec 460, and by bioluminescent assay of ATP using a 1250 luminometer (LKB-Wallac).

RESULTS

Susceptibility results after 7 days showed excellent correlation with conventionally determined MICs. 714 susceptibility tests were performed by both techniques, with seven major discrepancies between the two systems. For pyrazinamide, agreement was 100%, but five strains of M tuberculosis, including one control, and 11 mycobacteria other than M tuberculosis (MOTT) failed to grow on Middlebrook agar at pH 5.5. 606 tests were performed by radiometry, with four major discrepancies between this technique and ATP bioluminescence. No particular species of Mycobacterium gave aberrant results. Contamination was a problem; 12 of the 119 strains tested were contaminated at day 1 and had to be repeated before results were obtained. Contamination of individual tests increased significantly after 7 days of incubation.

CONCLUSIONS

ATP bioluminescence can be used to monitor mycobacterial growth in fluid culture media; the technique has considerable potential for rapid susceptibility testing. Advantages include lower initial cost of analytical equipment, lower reagent cost per test, and the use of non-radioactive substrates.

Perceived exertion. Antecedents and applications

The field of perceived exertion has largely concerned itself with the problem of identifying the primary antecedents to this psychophysiological phenomenon. A vast literature has evolved addressing this problem, but it is fraught with contradictions. At this stage a comprehensive theory of perceived exertion does not exist. It is generally accepted that perception of exertion is dominated by physiological determinants. Physiological sensory cues have been separated into 2 categories: local factors (sensations from the working muscles and joints), and central factors (sensations from the cardiopulmonary system). Major reviews in this area generally agree that local factors dominate perception of exertion. Recent work in perceived exertion has placed an emphasis on examining the contributing psychological factors. Research into the psychological factors affecting perceived exertion has been highly fragmented with no apparent theoretical framework as a base. At the same time it is clear that an integration of psychological and physiological variables is required to obtain theoretically meaningful knowledge of this multidimensional construct. The assumed dominance of physiological factors has been challenged by the contention that in field situations, in which a variety of social psychological influences operate, psychological determinants of perceived exertion may be vastly more influential than previously estimated. Identification of the primary determinants of perceived exertion and knowledge of how these factors are integrated is vital for a concrete theory of perceived exertion to evolve.