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Biomedical subjects

P A Jenkins

Publications and source records attributed to P A Jenkins.

At least 19 recordsLinked to original sources
PubMed2003

Pulmonary disease caused by Mycobacterium xenopi in HIV-negative patients: five year follow-up of patients receiving standardised treatment.

The literature concerning the management of pulmonary disease caused by Mycobacterium xenopi is scanty and consists of retrospective reports, mostly of small series of patients. Our aim was to document the clinical features and response to treatment of this rare but challenging disease. Patients were treated in a randomised, multi-centre trial with either rifampicin plus ethambutol or rifampicin, ethambutol and isoniazid. Clinical, bacteriological and radiological progress was monitored at set intervals for 5 years. As no differences emerged between the two groups, the results have been combined to provide this prospective survey. Forty-two patients were studied. Mean age was 65 years, three-quarters were male and two-thirds had other lung disease(s). Sputum was positive on direct smear in 62%. Cavitation was present in 81%, mostly large cavities, and disease was extensive in 38%. Despite good clinical response and little toxicity the death rate was high (69%), but less than 10% died primarily because of the M. xenopi disease. The failure of treatment/relapse rate was 12%. Only 11 (26%) were known to be alive at 5 years of whom seven (17%) were known to be cured. There was no correlation between failure of treatment/relapse and in vitro resistance. Better methods of susceptibility testing and more effective regimens are needed, but it is also evident that improved management of concomitant diseases and better general health will play a major part in increasing survival.

Adult↗
PubMed2001

Environmental mycobacteria in northern Malawi: implications for the epidemiology of tuberculosis and leprosy.

More than 36000 individuals living in rural Malawi were skin tested with antigens derived from 12 different species of environmental mycobacteria. Most were simultaneously tested with RT23 tuberculin, and all were followed up for both tuberculosis and leprosy incidence. Skin test results indicated widespread sensitivity to the environmental antigens, in particular to Mycobacterium scrofulaceum, M. intracellulare and one strain of M. fortuitum. Individuals with evidence of exposure to 'fast growers' (i.e. with induration to antigens from fast growers which exceeded their sensitivity to tuberculin), but not those exposed to 'slow growers', were at reduced risk of contracting both tuberculosis and leprosy, compared to individuals whose indurations to the environmental antigen were less than that to tuberculin. This evidence for cross protection from natural exposure to certain environmental mycobacteria may explain geographic distributions of mycobacterial disease and has important implications for the mechanisms and measurement of protection by mycobacterial vaccines.

Adolescent↗
PubMed2000

Trends in antituberculosis drug resistance in Karonga District, Malawi, 1986-1998.

SETTING: Karonga District, Malawi. OBJECTIVES: To examine long term trends in initial and acquired resistance to antituberculosis drugs in a rural area of Africa. DESIGN: Monitoring of all patients with culture-confirmed tuberculosis 1986-1998. RESULTS: Initial drug resistance results were available for 1121 patients. The proportion resistant to any of the first line drugs (streptomycin, isoniazid, rifampicin or ethambutol) was 9.6%, and to isoniazid 7.2%. Initial resistance to at least isoniazid and rifampicin (multidrug resistance) was seen in only six patients. No initial resistance to ethambutol was found. There was no significant change in initial drug resistance over time. Overall, 22/120 (18%) patients with previous treatment were resistant to at least one drug; only one had multidrug resistance. Acquired resistance decreased over the period of the study. There were no associations between age, sex or human immunodeficiency virus (HIV) status and initial or acquired drug resistance. CONCLUSIONS: Changes in acquired resistance may reflect the recent performance of a control programme more quickly than those in initial resistance. It is encouraging that acquired resistance decreased and levels of multidrug resistance were low despite more than a decade of use of rifampicin. The lack of association between HIV and drug resistance confirms findings elsewhere in Africa.

Adult↗
PubMed1996

Opportunist mycobacteria in England and Wales: 1982 to 1994.

Three thousand and fifty-two infections with opportunist mycobacteria were reported to the PHLS Communicable Disease Surveillance Centre from 1982 to 1994. The commonest reported species was Mycobacterium avium-intracellulare (MAI), followed by M. kansasii and M. malmoense. The annual totals of opportunist mycobacteria increased steadily over this period, mostly, but not exclusively, due to an increase in reports of MAI associated with HIV infection. There were also increases in reports of MAI not associated with HIV infection, and in reports of M. malmoense. The increase in reports of opportunist mycobacteria was seen throughout England and Wales, but underreporting of MAI infection in the National Health Service Thames regions appears to have increased in recent years. Continued referral of isolates of opportunist mycobacteria to one of the PHLS regional centres for mycobacteriology or the Mycobacterium Reference Unit, and reporting to CDSC, is essential for the surveillance of these infections.

AIDS-Related Opportunistic Infections↗
PubMed1996

Feline tuberculosis: a literature review and discussion of 19 cases caused by an unusual mycobacterial variant.

The literature relating to feline mycobacterial disease is reviewed and 19 cats with tuberculosis caused by a previously unknown strain of mycobacterium are discussed. The bacteria were found to have characteristics between those of Mycobacterium tuberculosis and M bovis. The paper considers the clinical signs, epidemiology and diagnosis of the cases, and discusses the possible origins of the organism, treatment regimens and zoonotic potential.

Animals↗
PubMed1996

Utility of PCR in diagnosing pulmonary tuberculosis.

At present, the rapid diagnosis of pulmonary tuberculosis rests with microscopy. However, this technique is insensitive and many cases of pulmonary tuberculosis cannot be initially confirmed. Nucleic acid amplification techniques are extremely sensitive, but when they are applied to tuberculosis diagnosis, they have given variable results. Investigators at six centers in Europe compared a standardized PCR system (Amplicor; Roche) against conventional culture methods. Defined clinical information was collected. Discrepant samples were retested, and inhibition assays and backup amplification with a separate primer pair were performed. Mycobacterium tuberculosis complex organisms were recovered from 654 (9.1%) of 7,194 samples and 293 (7.8%) of 3,738 patients. Four hundred fifty-two of the M. tuberculosis isolates from 204 patients were smear positive and culture positive. Among the culture-positive specimens, PCR had a sensitivity of 91.4% for smear-positive specimens and 60.9% for smear-negative specimens, with a specificity of 96.1%. Analysis of 254 PCR-positive, culture-negative specimens with discrepant results revealed that 130 were from patients with recently diagnosed tuberculosis and 94 represented a presumed laboratory error. Similar analysis of 118 PCR-negative, culture-positive specimens demonstrated that 27 discrepancies were due to presumed uneven aliquot distribution and 11 were due to presumed laboratory error; PCR inhibitors were detected in 8 specimens. Amplicor enables laboratories with little previous experience with nucleic acid amplification to perform PCR. Disease in more than 60% of the patients with tuberculosis with smear-negative, culture-positive specimens can be diagnosed at the time of admission, and potentially all patients with smear-positive specimens can immediately be confirmed as being infected with M. tuberculosis, leading to improved clinical management.

Bacteriological Techniques↗
PubMed1995

Patterns of initial and acquired antituberculosis drug resistance in Karonga District, Malawi.

There is concern that drug-resistant tuberculosis is increasing and may be concentrated among HIV-positive patients. Little information is available from developing countries, where surveillance studies are often unable to distinguish resistance in previously untreated patients (initial resistance) from resistance acquired following drug therapy, and where information on the HIV status of the patients is rare. Initial resistance patterns reflect the strains being transmitted in the community. We have studied patterns of resistance in northern Malawi, where the Lepra Evaluation Project has been collecting data on drug resistance since 1986. Initial drug sensitivity results were available for 373 new cases of tuberculosis. Initial resistance to at least one drug was found in 44 of these patients (11.8%, 95% CI 8.5-15.1): 13 were resistant to streptomycin alone, 13 to isoniazid alone, and 17 to more than one drug. Only 3 patients showed initial rifampicin resistance-1 in isolation, 1 in combination with streptomycin, and 1 with triple resistance. Drug resistance was not related to age, sex, or HIV status of the patient and there was no evidence of any increase over the period studied. There was no evidence of geographic clustering of the resistant strains, or of any increased risk of resistant strains in households with previous tuberculosis cases. Acquired resistance during follow-up was found in 5 of 329 patients with documented initially fully sensitive strains. 5 patients with initial resistance seemed to show reversion to sensitivity. The absence of an increase in drug resistance, despite an increase in tuberculosis cases over the period, is encouraging for the control programme. It emphasises the need to collect information from many areas before assuming that increases in antituberculosis drug resistance are occurring worldwide.

Adult↗
PubMed1995

Isolation of Mycobacterium malmoense from the environment in Zaire.

Two strains of mycobacteria isolated from water and soil in Zaire were identified as Mycobacterium malmoense by biochemical tests and lipid analysis. Apart from the previously reported fatty acids characteristic of this species, both strains, as well as 5 clinical isolates of M. malmoense, contained 2,4-dimethyl-docosanoic acid. One of the environmental strains, with a glycolipid pattern II, additionally contained 2-methyltetradecanoic acid. The results confirm that M. malmoense may be subdivided in 2 sub-groups according to its lipid patterns. They also show that M. malmoense can be isolated from the environment which may be the source of the infection.

Democratic Republic of the Congo↗
PubMed1995

Potentiation of the effects of chlorhexidine diacetate and cetylpyridinium chloride on mycobacteria by ethambutol.

Ethambutol enhanced the effects of chlorhexidine diacetate and cetylpyridinium chloride against Mycobacterium avium, M. bovis BCG, M. fortuitum and M. phlei. The findings show that it is possible to increase the susceptibility of mycobacteria to agents that normally exhibit poor activity against these organisms because of their reduced cellular penetration.

Anti-Infective Agents, Local↗
PubMed1994

False-positive Mycobacterium avium-intracellulare cultures with the Bactec 460 TB system.

Isolation of Mycobacterium avium-intracellulare from a number of specimens cultured with the Bactec 460 TB system was suspected to be due to carry-over contamination. The analysis of culture records and of the typing results confirmed this hypothesis. The problem seems to have been eliminated after replacement of the needle heater and increase of the needle temperature. We recommend that a number of precautions should be taken to reduce the risk of reporting false positive mycobacterial cultures.

Bacteriological Techniques↗
PubMed1993

Drug resistance in initial isolates of Mycobacterium tuberculosis in England and Wales, 1982-1991.

A total of 1833 out of over 16,000 'initial' isolates of Mycobacterium tuberculosis, submitted by hospital laboratories to the PHLS Regional Tuberculosis Centres in England and Wales between 1982 and 1991, were resistant to one or more first line anti-tuberculosis drugs. Isoniazid resistance was found in 6.1% of these strains, half of which were resistant to isoniazid alone. Resistance to isoniazid and rifampicin, with or without resistance to other drugs, was found in 0.6% of isolates. The proportion of initial isolates resistant to one or more drugs was 9.8%. It ranged from 8.0% to 10.9% between 1982 and 1990, and increased to 14.2% in 1991. The incidence of multiple drug resistance remained very low throughout the period. However, in the light of the problems with tuberculosis and drug resistance emerging elsewhere in the world, vigilance is essential, and enhanced surveillance is being planned in England and Wales.

Adolescent↗