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Biomedical subjects

R Lumb

Publications and source records attributed to R Lumb.

At least 19 recordsLinked to original sources
PubMed2006

A community-based TB drug susceptibility study in Mimika District, Papua Province, Indonesia.

SETTING: A district level tuberculosis (TB) control programme in Papua Province, Indonesia. OBJECTIVE: To determine the nature and extent of drug-resistant TB in newly diagnosed sputum smear-positive patients. METHODS: Sputum was collected from previously untreated smear-positive pulmonary TB patients diagnosed in the district over a 10-month period. Sputum specimens were processed and inoculated into a BACTEC MGIT960 tube. Isolates were identified by Ziehl-Neelsen staining, hybridisation with nucleic acid probes and biochemical investigations. Susceptibility testing was performed using the radiometric proportion method. Pyrazinamide testing was performed using the Wayne indirect method. RESULTS: One hundred and seven patients had sputum sent to a reference laboratory; 101 (94.4%) were culture-positive for Mycobacterium tuberculosis, with 87 (86.1%) fully sensitive to first-line anti-tuberculosis drugs. Two per cent were multidrug-resistant (MDR-TB) and 12 (11.9%) had other drug resistance. Each of the MDR-TB isolates was susceptible to amikacin, capreomycin, ciprofloxacin and para-aminosalicylic acid (PAS), but were resistant to rifabutin. One isolate was also resistant to ethionamide. CONCLUSIONS: MDR-TB is present in Indonesia but is not a major problem for TB control in this district. Generalisability to other districts in Indonesia, particularly large urban areas, needs to be confirmed by future studies.

Adolescent↗
PubMed2006

An alternative method for sputum storage and transport for mycobacterium tuberculosis drug resistance surveys.

SETTING: A district level tuberculosis (TB) programme in Indonesia. OBJECTIVE: To evaluate whether a single sputum specimen could be stored by refrigeration for an extended period of time, then transported to a reference laboratory and successfully cultured for Mycobacterium tuberculosis. METHODS: Single sputum specimens were collected from newly diagnosed smear-positive pulmonary TB patients, refrigerated at the study site without addition of 1% cetylpyridinium chloride, batched and sent to the reference laboratory, where they were decontaminated and inoculated into BACTEC MGIT 960 liquid media. RESULTS: One hundred and seven patients were enrolled. The median specimen storage time was 12 days (range 1-38) and median transportation time was 4 days (2-12). The median time from specimen collection until processing was 18 days (4-42). Only 4 (3.7%) specimens failed to grow Mycobacterium species and M. tuberculosis was isolated from 101 (94.4%) specimens. Six specimens with breakthrough contamination successfully grew M. tuberculosis after a second decontamination procedure. CONCLUSIONS: Single sputum specimens collected at a remote setting, refrigerated for relatively long periods without preservatives and transported without refrigeration to a reference laboratory can yield a high positive culture rate. These findings offer potential logistic simplification and cost savings for drug resistance surveys in low-resource countries.

Data Collection↗
PubMed2006

Not all microscopes are equal.

A functional microscope is the most important and most expensive piece of equipment required for smear microscopy. Global Fund monies have provided a unique opportunity to equip laboratories in low-resource countries, but these funds must be spent wisely. Cheap microscopes are superficially appealing. However, higher-quality microscopes generally have better optics and last longer. International agencies should consider establishing a purchasing service to assist countries in their microscope procurement. Such a system would provide quality assurance and increased purchasing power.

Humans↗
PubMed2005

Analysis of Mycobacterium tuberculosis isolates from treatment failure patients living in East Timor.

SETTING: In the first 2 years of the East Timor National TB Control Programme, 7960 new patients were treated (2RHZE/6HE) and 224 received a retreatment regimen (2SRHZE/1RHZE/4R3H3Z3E3). OBJECTIVE: To determine the nature and extent of drug-resistant tuberculosis (TB) in treatment failure cases in East Timor. METHODS: Sputum specimens from retreatment failure cases were processed and inoculated into a BACTEC MGIT960 tube and onto Löwenstein-Jensen media. Isolates were identified by Ziehl-Neelsen staining, hybridisation with nucleic acid probes and biochemical investigations. Susceptibility testing was performed using the radiometric proportion method. Pyrazinamide testing was performed using the Wayne indirect method. RESULTS: Eighteen patients failed retreatment (0.7% of new cases) and 14 were available for analysis. Mycobacterium tuberculosis was cultured from all specimens, despite considerable transport delays. Nine (64.3%) had multiple drug resistance (MDR-TB) and four (28.6%) had other drug resistance. All MDR-TB isolates were susceptible to amikacin, capreomycin and ethionamide, with most also susceptible to ciprofloxacin and para-aminosalicylic acid (PAS). CONCLUSIONS: An excellent TB control programme has been established in East Timor. If funds are available, East Timor provides an ideal setting for a small-scale DOTS-Plus programme to treat prevalent cases of MDR-TB, and this study could inform the second-line drug regimen.

Antitubercular Agents↗
PubMed2002

Nocardia asteroides isolated from three patients with cystic fibrosis.

Over a 7-year period, three patients with cystic fibrosis had multiple sputum specimens that were smear- and culture-positive for Nocardia asteroides. Two of the patients had received long-term, low-dose inhalational corticosteroid therapy. Although all three patients were treated with cotrimoxazole, resulting in eradication of the organism from the sputum, there was no change in their clinical state, radiological findings, or pulmonary function. The isolation of Nocardia asteroides from the respiratory tract of cystic fibrosis patients is an unusual finding. Its presence does not necessarily imply disease, and in these three cases, it most likely represented colonisation. The clinical significance of Nocardia spp. isolated from the respiratory tract of cystic fibrosis patients needs to be considered in the context of the individual clinical picture.

Adolescent↗
PubMed2002

Commensal ocular bacteria degrade mucins.

BACKGROUND/AIMS: Antimicrobial activity in tears prevents infection while maintaining a commensal bacterial population. The relation between mucin and commensal bacteria was assessed to determine whether commensals possess mucinolytic activity, how degradation depends on mucin integrity, and whether mucins affect bacterial replication. METHODS: Bacteria were sampled from healthy eyes and contact lenses from asymptomatic wearers. Intracellular mucins were extracted and purified from cadaver conjunctivas, and surface mucins from extended wear contact lenses. After exposure to bacteria, changes in mucin hydrodynamic volume (proteolytic cleavage) and subunit charge (oligosaccharide degradation) were assayed by size exclusion and ion exchange chromatography. The effect of mucin on bacterial replication was followed for up to 24 hours from the end of incubation with purified ocular mucins. RESULTS: Ocular bacteria decreased the hydrodynamic volume of intracellular and contact lens adherent mucins, irrespective of glycosylation density. A decrease in mucin sialylation was observed after exposure to commensal bacteria. Subunit charge distributions were generally shifted to lesser negative charge, consistent with loss of charged epitopes. Subunits with high negative charge, observed after digesting lightly adhering contact lens mucins with bacteria, suggest preferential cleavage sites in the mucin molecule. The presence of purified ocular mucin in the medium inhibited bacterial growth. CONCLUSION: Bacteria in the healthy ocular surface possess mucinolytic activity on both intact and surface processed mucins, targeted to discrete sites in the mucin molecule. Inhibition of bacterial growth by ocular mucins can be seen as part of the mucosal control of microbiota.

Adult↗
PubMed2000

Screening for refractive errors with the Topcon PR2000 Pediatric Refractometer.

PURPOSE: The PR2000 (Topcon, Tokyo, Japan) is a photorefractor that has been used in a population study comparing different methods of screening preschool children. The present study was conducted to determine the accuracy of the device in a largely clinical population. METHODS: Two hundred twenty-two children less than 8 years of age were included. All children were examined by an orthoptist using the PR2000 without inducing cycloplegia. All children then underwent retinoscopy with cycloplegia by an examiner who was unaware of the results from the PR2000 examination. RESULTS: The PR2000 gave a numerical reading for 90% of the children's right eyes and the message "Out of range" for a further 5%. The readings underestimated the amount of hypermetropic or astigmatic refractive error found on retinoscopy by an amount proportional to the magnitude of the refractive error. Agreement with retinoscopy for the axis of astigmatism more than 0.75 D was moderately good (intraclass correlation coefficient [ICC] = 0.63). The PR2000 was more useful as a screener, especially for anisometropia for which it was 91% sensitive and 92% specific. The repeatability was good for sphere (ICC = 0.74), less so for astigmatism (ICC = 0.59), and better than the optometrist for anisometropia (ICC = 0.38). The presence of nonrefractive diagnoses and the age of the children examined made little difference in the screening results. CONCLUSIONS: The PR2000 underestimated hypermetropic refractive errors when used without cycloplegia. However, it was at least as good a screening device as other similar instruments, especially when judged by its ability to detect anisometropia and the repeatability of the results.

Child↗
PubMed1999

Multicenter evaluation of the Abbott LCx Mycobacterium tuberculosis ligase chain reaction assay.

Four Australian hospital laboratories evaluated the performance of the Abbott LCx Mycobacterium tuberculosis assay with 2,347 specimens (2,083 respiratory and 264 nonrespiratory specimens) obtained from 1, 411 patients. A total of 152 specimens (6.5%) were culture positive for Mycobacterium tuberculosis complex (MTBC); of these, 79 (52%) were smear positive. After resolution of discrepant data, the overall sensitivity, specificity, and positive and negative predictive values for the LCx assay were 69.7, 99.9, 99.1, and 97.7% respectively. For smear-positive respiratory specimens that were culture positive for MTBC, the values were 98.5, 100, 100, and 98.4%, respectively, while the values for smear-negative respiratory specimens were 41.5, 99.9, 96.4, and 98%, respectively. Relative operating characteristic curves were constructed to demonstrate the relationship between sensitivity and specificity for a range of possible cutoff values in the LCx assay. These graphs suggested that the assay sensitivity for respiratory samples could be increased from 70.2 to 78.6%, while the specificity would be reduced from 99.9 to 99.4% by inclusion of a grey zone (i.e., LCx assay values of between 0.2 and 0.99). An algorithm is presented for the handling of specimens with LCx assay values within this grey zone.

DNA Ligases↗
PubMed1998

Isolation of a novel mycobacterium from an adolescent with cervical lymphadenitis.

A slow-growing mycobacterium was isolated from a cervical lymph node of an adolescent male. This isolate produced small, smooth, scotochromogenic colonies after 6 weeks of incubation at 25 degrees C and 30 degrees C (but not at 37 degrees C or 43 degrees C). The results of 16S-rRNA gene sequencing and high-performance liquid chromatography suggest that this isolate belongs to a hitherto unrecognised pathogenic species.

Adolescent↗
PubMed1998

Concurrent infection due to Shewanella putrefaciens and Mycobacterium marinum acquired at the beach.

Infection with marine bacteria is uncommon. A patient with systemic lupus erythematosus who developed concurrent infection with Shewanella putrefaciens and Mycobacterium marinum (M. marinum) is described. After bathing leg ulcers in sea water, severe cellulitis of the left leg with necrotic areas and extensive bullae developed. Infection due to S. putrefaciens was confirmed and a long course of hospitalization, oral ciprofloxacin and skin grafting was required. During hospitalization subcutaneous nodules developed on the other leg. Biopsy revealed acid-fast bacilli and culture grew M. marinum. These lesions responded to rifampicin and cotrimoxazole. Patients with leg ulcers, peripheral vascular disease, diabetes, or receiving immunosuppressive drugs may acquire unusual infections after salt water exposure.

Aged↗
PubMed1997

Phenotypic and molecular characterization of three clinical isolates of Mycobacterium interjectum.

Introduction of molecular biology-based technology into an Australian mycobacterial reference laboratory has resulted in the identification of three isolates of Mycobacterium interjectum in the past 12 months. Conventional phenotypic methods failed to identify the species of these isolates, and high-performance liquid chromatography found that only one of the three isolates had a mycolic acid pattern similar to that of the type strain. In contrast, all three isolates were rapidly identified as M. interjectum by 16S rRNA gene sequence analysis. Two isolates were recovered from the lymph nodes of children with cervical lymphadenitis, confirming the pathogenicity of this organism. However, the third isolate was obtained from the sputum of an elderly male with chronic lung disease without evidence of clinical or radiological progression, suggesting that isolation of M. interjectum should not imply disease. With the increasing use of molecular biology-based technology in mycobacterial laboratories, M. interjectum may be recognized more frequently as a pathogen or commensal organism.

Aged↗
PubMed1995

Tuberculosis in Australia, 1989-1992. Bacteriologically confirmed cases and drug resistance.

OBJECTIVE: To collate statistics, including drug susceptibility, of patients with bacteriologically confirmed tuberculosis in Australia during 1989-1992. DESIGN: Collaborative project among the five Australian mycobacterial reference laboratories. STUDY POPULATION: 2509 Australian residents with bacteriologically confirmed tuberculosis. OUTCOME MEASURES: Patient and specimen data, and drug susceptibility results recorded for isolates of Mycobacterium tuberculosis and Mycobacterium bovis. RESULTS: The annual incidence during 1989-1992 was about 3.6 per 100,000. The male-to-female ratio was 1.4:1 and about half the patients were under 50. Older men had high rates of disease. Lymphatic disease was significantly more common in females; the converse was true for pulmonary and pleural disease. Resistance to at least one of the common antituberculosis drugs was detected in 14.4% of isolates, and usually involved streptomycin (7.6%) and isoniazid (8.4%). Fewer than 1% of isolates were resistant to isoniazid and rifampicin in combination. CONCLUSIONS: By international standards, Australia remains a "low-incidence" country for tuberculosis, with a static annual incidence. Multiple drug resistance is uncommon and most patients should respond to the standard four-drug regimen. Nevertheless, because clinical data confirm that the pool of infected persons is being supplemented through immigration, and that certain population subgroups have high rates of disease, it is essential that Australia maintain effective control programs.

AIDS-Related Opportunistic Infections↗
PubMed1994

Coccidian/cyanobacterium-like body associated diarrhea in an Australian traveller returning from overseas.

Coccidian/cyanobacterium-like body (CLB) associated diarrhea occurred in a 42 yr old Australian woman returning from Bali, Indonesia. The patient had a diarrheal illness of 10 days duration with symptoms of explosive diarrhea, nausea, anorexia and fever. Fecal examination revealed CLBs which were detected in modified Ziehl-Neelsen stained fecal smears. No other bacterial or parasite pathogens were found. CLBs were variably acid fast, showed an intense blue auto-fluorescence under UV microscopy and appeared as non-refractile hyaline spheres in direct wet mounts, being 8-9 microns in diameter. The taxonomic status of CLBs has been unclear but recent evidence supports that they are a coccidian parasite of the genus Cyclospora, rather than cyanobacterium. There is no specific therapy for CLB enteritis and spontaneous recovery occurs after what may be a prolonged diarrheal illness. CLBs may be a previously unrecognized enteric pathogen although their role in the pathology of diarrheal illness is still undetermined. There is consistency in the clinical and laboratory findings amongst the reported cases and CLBs should be considered in persons with unexplained gastroenteritis, especially travellers returning from tropical regions.

Adult↗
PubMed1993

Identification of the microsporidian parasite, Enterocytozoon bieneusi in faecal samples and intestinal biopsies from an AIDS patient.

The microsporidian parasite, Enterocytozoon bieneusi, is currently recognized as a potentially important cause of chronic diarrhoea in patients infected with the human immunodeficiency virus (HIV). Faecal concentrates from a 38-year-old, HIV-seropositive patient examined by light and electron microscopy revealed the presence of numerous microsporidian spores. The structural characteristics of the spores were consistent with those previously described for Enterocytozoon bieneusi. Each spore contained a single nucleus, a posterior vacuole and a polar filament with 6-7 overlapping coils which appeared in cross-section as a series of 3 doublets. Mature spores were surrounded by an inner unit membrane, an electron-lucent endospore and a thin, electron-dense exospore. The identity of the parasite was confirmed by the detection of unique endogenous developmental stages in duodenal biopsies. Both proliferative and sporogonial plasmodia (meronts and sporonts) were observed and all stages were monokaryotic (single nucleus) and apansporoblastic (sporophorous vesicle absent). Proliferative and sporogonial plasmodia divided by plasmotomy and spore organelles (polar filament, attachment disc and polaroplast) were well developed prior to fission of the sporogonial plasmodium.

AIDS-Related Opportunistic Infections↗
PubMed1993

Rapid identification of mycobacteria by the Gen-Probe Accuprobe system.

Chemiluminescent acridinium ester-labelled (AE)-DNA probes (Gen-Probe, Inc., San Diego, Calif.) for the identification of Mycobacterium tuberculosis complex (MTBC) and the M. avium-M. intracellulare complex (MAC) were evaluated using 184 mycobacterial isolates cultured in BACTEC 12B vials (Becton Dickinson and Co., Towson, Md.). A 1.5 mL aliquot from BACTEC 12B vials containing acid-fast bacilli and a Growth Index of > 200 was concentrated 15-fold using a centrifugation step prior to performing the test procedure. When 184 mycobacterial isolates were tested (42MTBC/142 nontuberculous mycobacteria) using the AE-MTBC probe, there was 100% sensitivity and specificity when compared with conventional identification procedures. Criteria for using the AE-MAC probe were defined to optimize results whilst minimizing laboratory costs. Ninety-one (64%) of AE-MTBC probe negative isolates failed to meet selection criteria and were not tested. When 51 (36%) of the AE-MTBC-probe negative mycobacterial isolates were tested, the AE-MAC probe was found to be 88% sensitive and 100% specific. The non-isotopic Gen-Probe test is a rapid and practical alternative to current procedures for differentiation of mycobacteria.

Bacteriological Techniques↗
PubMed1992

Mycobacterium bovis (BCG) vaccination. Progressive disease in a patient asymptomatically infected with the human immunodeficiency virus.

OBJECTIVE: To report a case of progressive disease caused by Mycobacterium bovis after BCG vaccination in a patient asymptomatically infected with the human immunodeficiency virus (HIV). CLINICAL FEATURES: A 34-year-old white man about to commence employment as a developmental care worker had a BCG vaccination. Five months later, he had a positive result to a serological test for HIV antibody. Nine months after BCG vaccination, he presented with fever (38.7 degrees C), a large left axillary lymph node and a small left pleural effusion. The lymph node was biopsied and acid-fast bacilli observed in Ziehl-Neelsen stained smears. Culture grew Mycobacterium bovis (BCG). TREATMENT AND OUTCOME: He was successfully treated with isoniazid, rifampicin and ethambutol for a period of nine months. CONCLUSION: BCG vaccination of asymptomatic HIV-positive patients is not recommended. The detection of those at risk for HIV infection before vaccination administration is essential. Self-exclusion based on information supplied to all potential recipients is likely to be the most effective method.

Adult↗