Piédrola G

Antibiotic susceptibility of bacterial strains isolated from patients with community-acquired urinary tract infections

Isolates from urine samples obtained during 1999 were identified and their susceptibility to antimicrobial agents studied along with any production of extended-spectrum beta-lactamases (ESBL) by Escherichia coli and Klebsiella pneumoniae. A total of 13774 samples were analysed using an automatic system for the detection of bacterial ATP (Coral, USA). Of these samples, 49% were reported to be positive and uncontaminated; bacteria most frequently isolated were E. coli (47%), Proteus mirabilis (7%), Enterococcus faecalis (6%) and K. pneumoniae (5%). The susceptibility studies showed 37% E. coli strains resistant to amoxycillin+clavulanate 33% to cotrimoxazole and 22% to ciprofloxacin. Seven strains of E. coli produced ESBL. Thirteen per cent of strains were resistant to cefuroxime but only (1%) to fosfomycin. Resistance to nitrofurantoin in K. pneumoniae was 38%. P. mirabilis showed 52% resistance to cotrimoxazole and 13% Staphylococcus aureus, were methicillin-resistant. E. faecalis did not show any special resistance to normal medication. Fosfomycin continued to show high activity against Gram-negative bacilli. However, enterococci, some species of staphylococci and yeasts were difficult to treat empirically. ESBL were detected in the isolates of E. coli and there were some methicillin-resistant strains of S. aureus.

Detection of mycobacterial DNA in papulonecrotic tuberculid lesions by polymerase chain reaction.

Tuberculids are a heterogenous group of cutaneous lesions. Recent discoveries of M. Tuberculosis DNA in these lesions by PCR suggest that M. tuberculosis could play a role in their pathogenesis. The aim of this study was to demonstrate the presence of M. tuberculosis DNA by polymerase chain reaction in papulonecrotic tuberculid lesions. Skin biopsy specimens from ten patients with papulonecrotic tuberculid lesions (histopathologic features) were studied. All of them tested solidly positive in a tuberculin intradermal test. A gene‐amplification PCR, using primers capable of amplifying DNA in the M. tuberculosis complex, was performed to detect M. tuberculosis DNA in the lesions. A 285‐bp sequence specific of M. tuberculosis complex was amplified and confirmed by Southern‐blot hybridation with a 32 p 5′‐labelled internal probe. No inhibitors were detected in the negative PCR samples. The PCR technique makes the detection of mycobacterial DNA in tuberculids a possibility, and therefore provides a rational basis for antituberculous therapy and for the clinical management of these disorders. J. Clin. Lab. Anal. 14:133–135, 2000.

Chlamydia pneumoniae DNA in the Arterial Wall of Patients with Peripheral Vascular Disease

AbstractBackground:Chlamydia pneumoniae is a human respiratory pathogen that has recently been related to the genesis of symptomatic atherosclerosis. C. pneumoniae has been studied more widely in relation to coronary atherosclerosis than to peripheral arterial occlusive disease (PAOD). The present study aimed to retrospectively analyze the presence of C. pneumoniae DNA in patients with PAOD. Materials and Methods: A seminested PCR method was applied on 85 samples from 71 patients with PAOD secondary to surgical treatment. The control group comprised 50 patients with chronic superficial venous insufficiency who required varicose resection surgery. Results: The number of patients, number of samples studied and percentage of patients found to be positive in the PCR study were 17, 18 and 59%, respectively, for arteries of the lower extremities: 15, 16 and 60% for aneurysm of the abdominal aorta; 22, 23 and 73% for carotid stenosis and 17, 18 and 65% for aortic stenosis. C. pneumoniae DNA was found in six external pudendal arteries (12%) of the control group, significantly lower than the incidence in the patient group (p < 0.0001). Conclusion: A causal relationship between chronic C. pneumoniae infection and PAOD cannot be ruled out. On the contrary, the high incidence of C. pneumoniae DNA detected in our patients suggest that C. pneumoniae infection may play some role in the pathogenesis of peripheral vascular disease.

Multiple Sclerosis and Human Herpesvirus 6

AbstractBackground: A possible but as yet unproven relationship has been proposed between the onset or persistence of multiple sclerosis (MS) symptoms and herpesviruses, including, most recently, human herpesvirus 6 (HHV-6). A study was conducted to investigate the presence of HHV-6 DNA and the synthesis of antibodies against HHV-6, cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in serum and cerebrospinal fluid (CSF) of patients with MS. Materials and Methods: PCR and ElISA were used to detect HHV-6 DNA and specific antibodies against HHV-6, CMV and EBV in 211 samples (139 sera and 72 CSF). There were three groups of samples: group I, paired samples of serum and CSF from 41 MS patients; group II, paired samples of serum and CSF from 31 patients with neurological diseases other than MS (OND); group III, 67 serum samples from 27 different MS patients undergoing serologic follow-up. Results: No HHV-6 DNA was found in any sample. Group I sera showed elevated anti-HHV-6 IgG and IgA levels. In group II, anti-CMV IgG was detected in one CSF sample and anti-HHV-6 IgM in one serum sample. Group III sera showed high concentrations of anti-HHV-6 IgG, IgA and IgM. Conclusion: Given the clinical implications of the presence of antibodies against HHV-6 in MS patients, a viral reactivation cannot be excluded as an environmental factor.

Insulin resistance in patients with a recent diagnosis of coronary artery disease

Objective To elucidate whether insulin resistance is present in coronary artery disease (CAD) at diagnosis and to study its relationship with other known cardiovascular risk factors. Methods We evaluated the incidence of insulin resistance in 40 newly diagnosed CAD patients. Fifteen healthy subjects were used as a control group. The patients and controls had no previous history of metabolic disorders, and were not being administered any medication that might have affected their insulin sensitivity. Immediately after diagnosis of CAD, a standard 75 g oral glucose-tolerance test (OGTT) and an insulin suppression test (IST) were performed on separate days. The IST consisted of a constant infusion of glucose, insulin and somatostatin for 150min; insulin resistance was estimated by determining the steady-state plasma glucose (SSPG) concentrations during the last 60min of the test. The insulin sensitivity index (ISI) was calculated by the formula ISI=(glucose infusion rate/SSPG] x 103. Results Insulin resistance, defined by an ISI below the normal range derived from the control group, was present in 82.5% of the CAD patients. As a group, the patients with CAD displayed lower ISI (means ± SD: 29.23 ± 11.23 versus 50.33 + 9.37 dl/kg per min, P<0.001) and higher SSPG (225 ± 57 versus 123 ± 24mg/dl, P<0.001) than did controls. Serum triglycerides and uric acid were higher and high-density lipoprotein cholesterol levels were lower in patients than they were in controls. No differences were observed in fasting plasma insulin, glucose, total and lowdensity lipoprotein cholesterol concentrations. An abnormal OGTT result was observed in 27 patients. The ISI was low in 88.8% of the patients with an abnormal OGTT result and in 69% of the 13 patients with a normal OGTT result. Conclusions Insulin resistance and even impaired glucose tolerance are common findings in CAD at diagnosis. The changes in the lipid profile and in uric acid levels paralleled the changes in insulin sensitivity. These results suggest that insulin resistance might play a role in the development of coronary atherosclerosis and that its early diagnosis might be important in the prophylaxis of CAD.

Reliability of low-avidity IgG and of IgA in the diagnosis of primary infection by rubella virus with adaptation of a commercial test.

The detection of IgA and low‐avidity IgG and antibodies in serum is a potentially useful marker of recent infection by a microorganism. We studied the reliability of IgG avidity and presence of IgA for the diagnosis of recent acute infection by rubella virus. Low‐avidity IgG (Avy‐EIA test) was determined with a modified commercial test using 8 molar urea (indirect ELISA, DiaSorin, Italy) and IgA was determined with a homemade indirect ELISA test. Twenty‐five patients with recent primary infection by rubella virus (group I) and 50 healthy subjects (group II) were studied. In group I low‐avidity IgG varied between 100 and 0% (67.3 ± 21.8%); IgA was present in 24 patients (96%). In group II low‐avidity IgG varied from 50.4 to 0% (19.8 ± 16.9%). IgA was present in 2 subjects (4%). The sensitivity of the Avi‐EIA and the IgA test was 92 and 96%, respectively; specificity was 100 and 96%, respectively. We conclude that both low‐avidity IgG and IgA tests are helpful and reliable for the diagnosis of recent primary infection. J. Clin. Lab. Anal. 13:1–4, 1999.

Human immunodeficiency virus type-1 can be detected in monocytes by polymerase chain reaction.

Lymphocytes and monocytes from 25 patients infected with human immunodeficiency virus type-1 (HIV-1)--13 asymptomatic, seven with the AIDS-related complex (ARC) and five with the acquired immunodeficiency syndrome (AIDS)--were lysed and subjected to PCR with three primer pairs: SK38/SK39 (gag), SK68/SK69 (env) and SK29/SK30 (LTR). Amplified DNA was solution-hybridised with 32P-labelled probes (SK19, SK70 and SK31, respectively) and detected by PAGE-autoradiography. HIV-1 DNA was detected as follows. Asymptomatic patients: monocytes--gag 61.5%, env 100%, LTR 0%; lymphocytes--gag 100%, env 92.3%, LTR 53.84%. ARC patients: monocytes--gag 71.4%, env 57.1%, LTR 0%; lymphocytes--gag 100%, env 71.4%, LTR 71.4%. AIDS patients: monocytes--gag 80.0%, env 100%, LTR 0%; lymphocytes--gag 100%, env 60%, LTR 60%. The presence of HIV-1 DNA was confirmed in the monocyte fraction. In this cell subset, the env gene-directed primers were the most effective for amplification, whereas the LTR gene-directed primers failed to amplify HIV-1 DNA. The different pattern of amplification found in monocytes may suggest that these cells could be infected by a genetic variant of the virus.

Activity of Daptomycin Against Multiresistant Clinical Isolates of Staphylococcus aureus and Streptococcus agalactiae

The activity of daptomycin against 141 Staphylococcus aureus and 63 Streptococcus agalactiae isolates was assessed. The isolates were previously characterized and showed resistance to the antibiotics normally used against gram-positive cocci. Daptomycin was active against 100% of the isolates (minimum inhibitory concentration [MIC(90)] = 0.5 microg/ml, for both species). This antibiotic shows good in vitro activity; therefore, it is an excellent therapeutic alternative against these isolates.

Immune complex p24 antigen: A new prognostic marker in human immunodeficiency virus infection

p24 antigen (p24 Ag) is usually not found in patients in the asymptomatic phase of HIV infection, mainly because it is bound to anti-p24 antibodies (p24 Ab), with which it forms immune complexes. Nine asymptomatic patients positive for HIV-1 antibodies (stage II CDC criteria) treated with rα-interferon were followed (7.5+/-0.5 months), and a basal and final sample were tested for p24 Ag immune complexes (p24 Ag-IC), free p24 Ag, p24 Ab, CD4 count, β2-microglobulin, properdin B factor, and C3 and C4 complement fractions. p24 Ag-IC was detected in 55.5% of the samples, whereas free p24 Ag was detected in 5.5%. The finding of no change or an increase in p24 Ag-IC serum levels may be considered a prognostic marker. We believe that p24 Ab cannot be used as a prognostic marker unless p24 Ag-IC detection is simultaneously evaluated. In der asymptomatischen Phase der HIV-Infektion läßt sich das p24 Antigen (p24 Ag) meist nicht nachweisen; dies ist vor allem darauf zurückzuführen, daß es an anti-p24 Antikörper (p24 Ab) gebunden ist und mit ihnen Immunkomplexe bildet. Bei neun anti-HIV-1 positiven, asymptomatischen Patienten (Stadium II nach CDC Kriterien), die mit r-alpha-Interferon behandelt wurden, wurden Verlaufsbeobachtungen (7,5 +/- 0,5 Monate) durchgeführt. Basis- und Abschlußuntersuchungen auf p24 Ag Immunkomplexe (p24 Ag-IC), freies p24 Ag, p24 Ab, CD4 Zellzahlen, β2-Mikroglobulin, Properdin B Faktor und Komplementfraktionen C3 und C4 wurden dabei vorgenommen. In 55,5% der Proben fand sich p24 Ag-IC, in 5,5% freies p24 Ag. Die Beobachtung gleichbleibender oder ansteigender Werte von p24 Ag-IC im Serum hat möglicherweise prognostische Bedeutung. Unserer Ansicht nach kann der p24 Ab nicht als prognostischer Marker eingesetzt werden, wenn nicht zugleich die Bestimmung von p24 Ag-IC erfolgt.Summaryp24 antigen (p24 Ag) is usually not found in patients in the asymptomatic phase of HIV infection, mainly because it is bound to anti-p24 antibodies (p24 Ab), with which it forms immune complexes. Nine asymptomatic patients positive for HIV-1 antibodies (stage II CDC criteria) treated with rα-interferon were followed (7.5+/-0.5 months), and a basal and final sample were tested for p24 Ag immune complexes (p24 Ag-IC), free p24 Ag, p24 Ab, CD4 count, β2-microglobulin, properdin B factor, and C3 and C4 complement fractions. p24 Ag-IC was detected in 55.5% of the samples, whereas free p24 Ag was detected in 5.5%. The finding of no change or an increase in p24 Ag-IC serum levels may be considered a prognostic marker. We believe that p24 Ab cannot be used as a prognostic marker unless p24 Ag-IC detection is simultaneously evaluated.ZusammenfassungIn der asymptomatischen Phase der HIV-Infektion läßt sich das p24 Antigen (p24 Ag) meist nicht nachweisen; dies ist vor allem darauf zurückzuführen, daß es an anti-p24 Antikörper (p24 Ab) gebunden ist und mit ihnen Immunkomplexe bildet. Bei neun anti-HIV-1 positiven, asymptomatischen Patienten (Stadium II nach CDC Kriterien), die mit r-alpha-Interferon behandelt wurden, wurden Verlaufsbeobachtungen (7,5 +/- 0,5 Monate) durchgeführt. Basis- und Abschlußuntersuchungen auf p24 Ag Immunkomplexe (p24 Ag-IC), freies p24 Ag, p24 Ab, CD4 Zellzahlen, β2-Mikroglobulin, Properdin B Faktor und Komplementfraktionen C3 und C4 wurden dabei vorgenommen. In 55,5% der Proben fand sich p24 Ag-IC, in 5,5% freies p24 Ag. Die Beobachtung gleichbleibender oder ansteigender Werte von p24 Ag-IC im Serum hat möglicherweise prognostische Bedeutung. Unserer Ansicht nach kann der p24 Ab nicht als prognostischer Marker eingesetzt werden, wenn nicht zugleich die Bestimmung von p24 Ag-IC erfolgt.

Clinical utility of a competitive ELISA to detect antibodies against Treponema pallidum.

Screening for Treponema pallidum infection is carried out on a large human population. To reduce costs, fewer tests which still offer adequate sensitivity and specificity could be performed. We studied the reliability of a novel indirect ELISA method to test for this infection. Several panels of sera were used that corresponded to 40 primary infections (group 1), 13 recurrences (group 2), 348 latent infections (group 3), 5 samples with anticardiolipin antibodies (group 4), 15 samples from patients with Lyme borreliosis (group 5), and 400 samples from blood donors and healthy pregnant women (group 6). The ELISA showed a global sensitivity and specificity of 100 and 99.5%, respectively. Our evaluation shows that Enzygnost Syphilis is a sensitive, specific, and simple test to screen for this infection. J. Clin. Lab. Anal. 14:83–86, 2000.