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Biomedical subjects

S M Arend

Publications and source records attributed to S M Arend.

At least 19 recordsLinked to original sources
PubMed2007

Effect of tuberculin skin testing on a Mycobacterium tuberculosis-specific interferon-gamma assay.

Recently, interferon-gamma release assays (IGRA) for specific diagnosis of Mycobacterium tuberculosis infection have become available. In recent UK tuberculosis (TB) guidelines, it has been advised to screen for latent M. tuberculosis infection using the tuberculin skin test (TST), followed by IGRA if the TST is positive. Since TST can boost immune responses to tuberculin, the present authors evaluated whether TST administration affects the result of QuantiFERON-TB Gold in-tube (QFT-GIT), a whole blood-based IGRA. QFT-GIT was performed on the day of TST administration and the day of reading in 15 TST-negative subjects, 46 TST-positive subjects with recent or remote exposure to M. tuberculosis and five cured TB patients. No systematic boosting of QFT-GIT responses from negative to positive was observed. Only in a few TST-positive persons did TST enhance pre-existing QFT-GIT responses. Screening for latent Mycobacterium tuberculosis infection using tuberculin skin testing followed by interferon-gamma release assays on the day of reading is a reliable approach, as the specificity of QuantiFERON-TB Gold in-tube is not affected by prior tuberculin skin test administration.

Adult↗
PubMed2006

Successful treatment of fungus balls due to fluconazole-resistant Candida sake obstructing ureter stents in a renal transplant patient.

Reported here is the case of a 72-year-old renal transplant recipient with stenosis of the neo-ureter requiring stents, who was admitted to hospital with pyonephrosis caused by fungus balls. Fluconazole-resistant Candida sake was grown. Treatment with external drainage of the renal pelvis and intravenous and local administration of caspofungin resulted in relief of the obstruction. Eradication of the infection was achieved by surgical removal of the ureter with all stents and construction of a cysto-pyelostomy.

Aged↗
PubMed2006

Prospective controlled study of the diagnostic value of skin biopsy in patients with presumed meningococcal disease.

Microbiological tests for diagnosis of acute meningococcal disease are important for the clinical management of patients with this often-fatal illness, but cultures are frequently negative after antibiotics have been administered. Retrospective studies suggest that examination of skin biopsies may aid a rapid diagnosis and that cultures of skin biopsies are often positive even after antimicrobial treatment has commenced. This prospective controlled study aimed to assess the diagnostic value of skin biopsy compared with investigations of blood and cerebrospinal fluid (CSF) in patients with skin lesions and presumed meningococcal disease. A total of 43 patients, 31 with suspected acute meningococcal infection and 12 controls, were included. All skin biopsies were investigated by Gram stain and routine microbiological culture. In 25 patients, meningococcal infection was diagnosed microbiologically. The clinical diagnosis was meningococcal meningitis in 8 patients, meningococcal sepsis in 11 patients, and a combination of both in 6 patients. The sensitivity of cultures of blood, CSF, and skin biopsies was 56%, 50%, and 36%, respectively. When culture and Gram stain were combined, positive results were obtained in 56%, 64%, and 56%, respectively. There was no correlation between the diagnostic yield of skin biopsies and previous antibiotic treatment. In 14 patients, the diagnosis was based exclusively on one positive sample: CSF in 7 (28%) patients, blood in 4 (16%) patients, and skin biopsy in 3 (12%) patients. The sensitivity of skin biopsies was highest in patients with the least extensive skin lesions. Specificity was 100%. Microbiological investigation of skin biopsies increased the diagnostic yield and could be considered a component of the routine diagnostic work-up in patients with suspected meningococcal infection, even after the initiation of antimicrobial treatment.

Adolescent↗
PubMed2006

Risk factors of acute hepatic failure during antituberculosis treatment: two cases and literature review.

Hepatotoxicity is a well-known side effect of antituberculosis treatment (ATT). If not recognised in time, drug-induced hepatitis can develop, which may rapidly progress to acute liver failure. We describe two patients with acute hepatic failure caused by ATT, whose pretreatment liver function had been normal. Both patients successfully underwent liver transplantation. Possible risk factors predisposing towards ATT-induced hepatic failure were evaluated, and at least four risk factors were present in these patients. Although available guidelines do not advocate routine monitoring of liver function during ATT unless baseline values are elevated or in the case of pre-existent liver disease, this is nevertheless common practice. Liver function should always be measured in patients who develop symptoms during ATT, and rising liver function parameters should prompt immediate action to prevent the occurrence of liver failure. This report underscores that regular monitoring of liver function parameters and adherence to guidelines is especially important in patients with risk factors for ATT-induced liver disease. An evaluation of chronic viral hepatitis in risk groups before starting ATT could be worthwhile.

Adult↗
PubMed2005

[Two patients with tuberculous pleurisy].

Tuberculous pleurisy was diagnosed in two patients, a 21-year-old Somali woman and a 19-year-old Surinam man. The first patient suffered from a paradoxical (immunological) reaction and the other had an infectious reaction. Both patients recovered after treatment with tuberculostatic agents and pleural drainage. The pathophysiology of the paradoxical reaction is still largely unclear. Culture continues to be the gold standard in diagnosing tuberculous pleuritis but, in many cases, bacteriological confirmation is not obtained. The (probable) diagnosis is then often made on the basis of a combination of the patient's history, estimation of the risk, physical examination, radiology and histology, and on the basis of a (trial) treatment with tuberculostatic agents. In the diagnostic process, a PCR on the Mycobacterium tuberculosis complex can be helpful. The routine determination of adenosine deaminase and interferon gamma in patients with tuberculous pleurisy is not useful in low-incidence countries such as The Netherlands. The measurement of the in-vitro T-cell reactivity against M. tuberculosis-specific antigens may be of more value in the future. The pharmacotherapy of tuberculous pleurisy is the same as that of pulmonary tuberculosis. Rinsing the pleural cavity is recommended in the case of an infectious reaction. Drainage of pleural fluid is indicated in the case of a paradoxical reaction if there are mechanical difficulties.

Adult↗
PubMed2004

Study of the antibody response against Mycobacterium tuberculosis antigens in Warao Amerindian children in Venezuela.

This study was aimed at investigating alternate methods for serodiagnosis of tuberculosis (TB), which are needed because bacteriologic diagnosis of childhood TB is difficult. A selection of 80 serum and saliva samples were tested from Warao indigenous children under 15 years of age; 34 high TB suspects (28 positive and 6 negative for the tuberculin skin test, TST) and 46 healthy contact children (32 positive and 14 negative for the TST). Several enzyme-linked immunosorbent assay (ELISA) serological tests were developed to test for Mycobacterium tuberculosis-specific antibodies, including serum IgA, IgG, IgE, and secretory IgA (sIgA) in saliva against 3 specific antigens (PPD, HSP60, 38 kDa). Of these, 2 antigens, PPD and 38 kDa, showed significantly higher reactivity. The sensitivity and specificity of these tests for diagnosis remained limited, between 26.5% and 38.2%, and 77.4% and 97%, respectively. Of all the samples studied and combinations realized between all isotypes and antigens combined with 3 isotypes (anti-PPD IgG, IgE, and anti-38kDa sIgA) managed to detect the largest number of patients, showing an improved sensitivity level of 64.7%, although specificity levels dropped to 81.8%. These results were compared with the Omega diagnostics commercial kit results. The commercial kits showed significantly lower reactivity (sensitivity of 20% and 13.33% to Myco G and Complex Plus, respectively) and a specificity of 100%. This study shows that in indigenous populations of Venezuela, where invasive procedures cannot be used to select samples but evaluation with a chest X-ray for radiological studies is available, the combination of 3 specific isotypes may be a useful tool to increase diagnostic accuracy with pulmonary TB in this population, when used together with clinical and epidemiological criteria.

Adolescent↗
PubMed2004

Cavitating pneumonia after treatment with infliximab and prednisone.

Tumor necrosis factor (TNF)-alpha antagonists constitute a novel class of immunomodulating drugs that are used for the treatment of an increasing number of inflammatory disorders. These agents are associated with an increased risk of tuberculosis, but the risk of other infections is less clear. Reported here is the case of a patient who developed cavitary pneumonia after treatment with infliximab (monoclonal TNF-alpha antibodies) and corticosteroids for rheumatoid arthritis. Cryptococcus neoformans was the only pathogen isolated from bronchoalveolar lavage fluid. The patient responded well to fluconazole. The risk of infection after treatment with TNF-alpha antagonists and the possible causative microorganisms are discussed.

Antibodies, Monoclonal↗
PubMed2004

Immunological crossreactivity of the Mycobacterium leprae CFP-10 with its homologue in Mycobacterium tuberculosis.

Mycobacterium tuberculosis culture filtrate protein-10 (CFP-10) (Rv3874) is considered a promising antigen for the immunodiagnosis of tuberculosis (TB) together with early secreted antigens of M. tuberculosis (ESAT-6). Both ESAT-6 and CFP-10 are encoded by the RD1 region that is deleted from all tested M. bovis bacille Calmette-Guérin (BCG) strains but present in M. leprae, M. tuberculosis, M. bovis, M. kansasii, M. africanum and M. marinum. In this study, the homologue of CFP-10 in M. leprae (ML0050) is identified and characterized. Interferon-gamma production in response to this homologue by T cells from leprosy patients, TB patients and unexposed controls shows that CFP-10 of M. leprae is a potent antigen that crossreacts with CFP-10 of M. tuberculosis at the T-cell level. This crossreactivity has implications for the use of CFP-10 of these mycobacterial species as diagnostic tool in areas endemic for both the diseases.

Amino Acid Sequence↗
PubMed2004

Correlation of virulence, lung pathology, bacterial load and delayed type hypersensitivity responses after infection with different Mycobacterium tuberculosis genotypes in a BALB/c mouse model.

One of the most intriguing aspects of tuberculosis is that the outcome of an infection with M. tuberculosis (TB) is highly variable between individuals. The possibility of differences in virulence between M. tuberculosis strains or genotypes has only recently been studied. There is evidence of multifactorial genetic predisposition in humans that influences the susceptibility to tuberculosis. A better understanding of differences in virulence between M. tuberculosis genotypes could be important with regard to the efforts at TB control and the development of improved antituberculosis vaccines. Survival, lung pathology, bacterial load and delayed type hypersensitivity (DTH) responses of BALB/c mice after intratracheal infection with any of 19 different M. tuberculosis complex strains of 11 major genotype families were studied. The results indicate that among genetically different M. tuberculosis strains a very broad response was present with respect to virulence, pathology, bacterial load and DTH. 'Low'-responders were the H37Rv, Canetti, Beijing-1 strains, while Beijing-2,3, Africa-2 and Somalia-2 strains were 'high'-responders. A severe pathological response correlates with a high mortality and a high CFU counts in lungs, but poorly with the degree of the DTH response.

Animals↗
PubMed2004

Pneumonia caused by Mycobacterium kansasii in a series of patients without recognised immune defect.

The clinical and epidemiological characteristics of 17 patients diagnosed with Mycobacterium kansasii pneumonia within a limited geographical region over a period of 10 years are described. An in-depth evaluation of the innate and adaptive immune systems was performed for five available patients. A comparison was made of the genetic fingerprint patterns of the isolates obtained by restriction fragment length polymorphism (RFLP) analysis, with the major polymorphic tandem repeat (MPTR) as a probe. Predisposing factors consisted of smoking, airway abnormalities, substance abuse, diabetes or poor general condition, but in two patients no risk factor was identified. In the five patients tested, no abnormalities or deficiencies were detected in the innate or adaptive type-1 immunity. All M. kansasii isolates had identical MPTR RFLP patterns, although no epidemiological connection could be established, and these were identical to those of clinical isolates from Australian patients. These data do not support the theory that defects in the innate or adaptive type-1 immunity have a role in the pathogenesis of invasive M. kansasii infections. The identical fingerprint patterns of the isolates suggested the existence of a virulent strain of M. kansasii.

Adult↗
PubMed2003

TNF-alpha blockade and tuberculosis: better look before you leap.

According to several reports, the risk of active tuberculosis in patients who are latently infected with Mycobacterium tuberculosis is increased after treatment with tumour necrosis factor alpha (TNF)-blocking agents. These drugs have demonstrated effectiveness and are increasingly being used for treatment of several inflammatory diseases, including rheumatoid arthritis and Crohn's disease. Specialists prescribing TNF-blocking agents should be aware of the risk of tuberculosis and other infections, the unusual and severe clinical presentations and the available preventive measures. In this review, we will weigh currently available data on the risk of infection with intracellular pathogens and in particular tuberculosis in patients treated with TNF-blocking agents, discuss the role of TNF in the pathogenesis of tuberculosis and describe the risk profile of this complication. Awaiting further consensus protocols, a provisional flow chart is presented that is based on dinical parameters to provide a logical framework to reduce and minimise the risk of tuberculosis during TNF blockade.

Antibodies, Monoclonal↗
PubMed2002

Is there evidence for recommending silver-coated urinary catheters in guidelines?

We evaluated the available literature on effectiveness of silver-coated versus uncoated catheters for the prevention of urinary tract infections in catheterized patients stratified by sex, systemic antibiotic use, renal function and duration of catheterization. Controlled clinical trials, randomized clinical trials and systematic reviews/meta-analysis were identified by a search strategy in Medline (1966-August 2001) and in the Cochrane Controlled Trials Register. Keywords were urinary catheterization, silver and infection. Trials using silver-coated catheters in the treatment group and uncoated catheters in the control group, with bacteriuria as the outcome measure, were selected. The quality of the methods used of all selected publications was assessed by using a quality assessment scale for randomized clinical trials. In addition we looked critically at subject-specific aspects. Data from the original publications were used to calculate the overall relative risk of bacteriuria in patients with silver-coated versus uncoated catheters, as well as the effect in subgroups. Thirteen trials and one meta-analysis were identified. Seven reports satisfied the selection criteria with only one achieving a high-quality score. Confounding variables were not considered in any trial. Additional studies with a high standard of internal quality and careful specification of the clinical question with regard to subject-specific critical points are necessary to decide whether the use of silver-coated catheters can be recommended.

Cross Infection↗
PubMed2002

Recurrent staphylococcal bacteraemia and subhepatic abscess associated with gallstones spilled during laparoscopic cholecystectomy two years earlier.

This is the first report of Staphylococcus aureus bacteraemia and subhepatic abscess in association with intraperitoneal gallstones spilled during laparoscopic cholecystectomy two years earlier. Spilled gallstones can lead to abscess formation in the late postoperative period by acting as foreign bodies that can become infected during bacteraemia and then become a source of recurrent bacteraemia.

Abdominal Abscess↗
PubMed2001

Repeatedly negative tuberculin skin tests followed by active tuberculosis in an immunocompetent individual.

We describe a woman who was repeatedly tuberculin (PPD) skin test negative after exposure to smear-positive tuberculosis (TB), but developed active TB with a positive skin test 7 years later. Molecular epidemiologic evidence is presented that the infection was contracted 7 years previously from the original source case. PPD skin testing is subject to many technical and biological variables and this report underscores that this tool can fail to detect latent TB infection in some cases. The causes of false-negative and false-positive PPD skin test results are reviewed.

Acute Disease↗