Showing papers in "Infection in 1999"

A new technology of microdispersed silver in polyurethane induces antimicrobial activity in central venous catheters.

Abstract: Metal ions or metal ions in complexes or compounds have been used for centuries to disinfect fluids, solids and tissues. The biocidal effect of silver, with its broad spectrum of activity including bacterial, fungal and viral agents, is particularly well known and the term “oligodynamic activity” was coined for this phenomenon. Silver ions have an affinity to sulfhydryl groups in enzyme systems of the cell wall, through which they interfere with the transmembranous energy transfer and electron transport of bacterial microorganisms. Silver ions also block the respiratory chain of microorganisms reversibly in low concentrations and irreversibly in higher concentrations. Binding to the DNA of bacteria and fungi increases the stability of the bacterial double helix and thus inhibits proliferation. There is no cross resistance with antibiotics and also no induction of antimicrobial resistance by silver ions. The concentrations required for bactericidal activity are in the range 10−9 mol/l. These concentrations can be achieved in solution by the interaction of metallic silver with electrolytes only if there is a large enough surface of silver. By a novel technology, metallic silver is distributed in submicron particles in polyurethane and results in a concentration of 0.8% in an active surface of 450 cm2/g polyurethane. Polyurethane is hygroscopic and rapidly attracts water; the interaction of electrolyte solutions with the extremely finely distributed silver throughout the polyurethane releases bactericidal concentrations of silver ions over a period of years to the surface of the material. The electronegatively charged surface of bacteria attracts the positively charged silver ions. The concentrations released from the polyurethane are far below the toxic concentrations for humans.

Combination therapy as a tool to prevent emergence of bacterial resistance.

Abstract: Emergence of resistance is an ever increasing problem. One of the methods by which emergence of resistance may possibly be prevented, or at least delayed, is the use of combination therapy. Since the emergence of resistant mutants is a direct result of selective pressure by antimicrobial therapy, the chance of mutants resistant to two antimicrobials in the parent population being present is a product of mutation frequencies, provided that resistance mechanisms are independent. Comparative studies in in vitro pharmacokinetic models and in vivo indicate that emergence of resistance is less common when combination therapy is used. This is particularly true for microorganisms known to develop resistance relatively quickly, such as Pseudomonas aeruginosa, and resistance mechanisms which occur at a relatively high frequency.

Outbreak of Candida parapsilosis fungemia in neonatal intensive care units: clinical implications and genotyping analysis.

Abstract: During a 5-month period, 17 infants hospitalized in neonatal intensive care units of a medical center and a branch hospital developed 18 episodes of Candida parapsilosis fungemia. The mean age at onset was 35 days. Prior to fungemia, all the infants had received hyperalimentation and antibiotics, and 15 infants had had central venous catheters. The presenting symptoms were variable but only vague in 40% of the episodes. Despite administration of antifungal agents, subsequent eradication of fungemia was achieved in only two-thirds of the episodes. None of the environmental samples was positive for C. parapsilosis, while 20% of hand-washing samples of staff working in both units yielded this microorganism. Four genotypes with two main types were identified from 14 outbreak strains and eight genotypes from 14 hand-washing strains, with one type predominant. The results suggest that C. parapsilosis fungemia increases the morbidity and mortality of neonates but does not cause acute lethal events. The outbreak was caused by two main genotypes, possibly via cross-infection by the hands of health care workers.

Multisystem organ failure secondary to increased intraabdominal pressure.

Abstract: Acutely increased intraabdominal pressure can lead to multisystem organ dysfunction. Organ dysfunction consists of acute pulmonary failure secondary to compressive atelectasis and associated with high peak inspiratory pressures and impaired gas exchange, acute renal failure with marked oliguria without hypernaturia, intestinal and hepatic ischemia possibly leading to bacterial translocation or necrosis with peritonitis, increased intracranial pressures which may cause brain dysfunction or aggravate head injury edema, venous thrombosis and thromboembolism, and abdominal wall ischemia or necrosis. The diagnosis is made clinically in a patient with high peak inspiratory pressures, oliguria and an apparently tight abdomen, although urinary bladder pressure > or = 20 cm H2O pressure is suggestive. However, chronically increased intraabdominal pressure as is seen in the morbidly obese, pregnancy and cirrhosis may be misleading. As to treatment, once the diagnosis is made, the patient's abdomen should be opened and the tension relieved. The intestinal contents need to be protected and evaporative water loss minimized by either closing the skin and not the fascia or, if this is not possible, using an impermeable protective dressing. If the abdomen is difficult to close at the primary operation, it is best to prevent the development of an acute abdominal compartment syndrome by closing only the skin or leaving it open and using an impermeable dressing. In conclusion, the acute abdominal compartment syndrome has become increasingly recognized as a cause for multisystem organ failure. Recognition of the problem or prevention is mandatory for optimal patient survival.

Reduced rates of catheter-associated infection by use of a new silver-impregnated central venous catheter.

Abstract: A central venous catheter with a new form of silver impregnation of the internal and external surfaces was investigated for antimicrobial activity and tolerance in patients in a controlled comparative, prospective and randomized clinical study. Commercially available catheters with no antimicrobial activity were used as controls. One hundred sixty-five catheters were included in the final evaluation. All catheters were percutaneously inserted for the first time with a duration of ≥5 days and a microbiological examination of the catheter tip. Catheter location (>90% internal jugular vein), mean duration of catheterization (8–9 days), patients' age and diagnosis were comparable in both groups. Silver-impregnated catheter tips showed an incidence of colonization in 14.2/1000 catheter days and control catheters in 22.8/1000 catheter days. This represents a reduction of 37.7%. Catheter-associated infections were diagnosed in the silver group in 5.26/1000 catheter days and 18.34/1000 catheter days in the control group, indicating a reduction rate of 71.3% (P<0.05, χ2-test). No complications or side effects were documented in either group.

Hyperlipidemia under treatment with proteinase inhibitors

Abstract: To define the extent and time course of HIV-proteinase inhibitor (PI) effects on serum lipid levels 148 patients on triple combination therapy including PIs and 91 patients on therapy with two nucleosides as a control group were evaluated. In the PI group there was a significant increase in total cholesterol after 3, 6 and 12 months compared to the baseline level (198, 204 and 203 vs. 176 mg/dl). The increase in triglycerides was 25.5% from the baseline at month 3. Indinavir had a significantly higher impact on cholesterol levels than saquinavir. No changes in lipids were seen in the control group. It was concluded that hyperlipidemia is associated with PI use, becomes evident within 3 months of treatment and seems to be substance specific.

Nosocomial infections in critically ill infectious disease patients: results of a 7-year focal surveillance.

Abstract: An incidence study on nosocomial infections in critically ill infectious disease patients was carried out in the intensive care unit (ICU) of a university hospital for infectious diseases over a 7-year period (1 January 1990 to 31 December 1996). A total 660 patients who stayed in the ICU for over 48 h were prospectively observed. The patients were divided into two groups: one with central nervous system infections (442 patients) and the other with other severe infections (218 patients). The risk of nosocomial sepsis and pneumonia was significantly higher in patients suffering from severe central nervous system infections. The incidence of sepsis was 24.2% vs 11.4% (relative risk 1.95; 95% confidence interval 1.32–2.89); the incidence of pneumonia was 30.5% vs 14.7% (relative risk 2.09; 95% confidence interval 1.47–2.96). The incidence of urinary tract infection was 14.3% vs 13.3% (relative risk 1.07; 95% confidence interval 0.71–1.61). Density rates of nosocomial septic episodes were 21.1±37.1 vs 11.7±32.4 episodes/100 central venous-line days (P<0.006). Nosocomial pneumonia occurred only in mechanically ventilated patients (36.9±61.2 vs 28.5±65.8 episodes per 1000 ventilatory days, P=0.012). Nosocomial urinary tract infection occurred only in patients with urinary catheters (11.6±60.7 episodes/1000 urinary catheter days vs 18.7±90.1, P=0.886). Multivariate regression analysis identified age, diagnosis of CNS infection, duration of urinary tract catheterization, the use of central venous lines and mechanical ventilation as independent risk factors of nosocomial sepsis. Duration of mechanical ventilation, use of steroids and diagnosis of CNS infection were independent risk factors of nosocomial pneumonia. A subanalysis identified tetanus patients to be at particular risk of nosocomial infections.

The Erlanger silver catheter: in vitro results for antimicrobial activity.

Abstract: The antimicrobial activity of a silver-impregnated polymer catheter (the Erlanger silver catheter) was demonstrated by determining the microbial adhesion to the surface of the catheter and by measuring the rate of proliferation (viability) of microorganisms at this site. On the surface of a catheter impregnated with silver, according to previously described methods, the bacterial adhesion ofStaphylococcus epidermidis is reduced by 28–40%. Bacterial proliferation on the surface of the catheter and biofilm production are also substantially reduced by the elution of free silver ions from the catheter matrix. Bacteriostatic and bactericidal activities can be determined. The antimicrobial efficacy of the silver catheter is not reduced by blood components. There is no loss in antimicrobial activity for weeks after preincubation in water or phosphate buffered saline. The antimicrobial activity depends on the extent of the active silver surface.

Epidemiology of MRSA.

Abstract: Staphylococcus aureus is recognized as one of the major causes of infections in humans occurring in both the community and the hospital. Up to now one of the most serious aspects as far as treatment of S. aureus infections is concerned is resistance to methicillin, which in clinical terms indicates resistance to all beta-lactam antibiotics. The growing incidence of methicillin-resistant S. aureus (MRSA) infections worldwide, their multidrug resistance, several reservoirs of resistant strains, the facility to spread also outside hospitals and to cause outbreaks requires efficacious infection control measures. For this reason microbiological and epidemiological studies are of crucial importance.

Enterohemorrhagic Escherichia coli (EHEC) in pediatric hemolytic-uremic syndrome: a prospective study in Germany and Austria.

Abstract: Studies from Europe indicate that infections with enterohemorrhagic Escherichia coli (EHEC) non-O157:H7 strains are increasing in frequency as a cause of hemolytic-uremic syndrome (HUS). In 1997 a prospective study was performed in Germany and Austria to assess the distribution of EHEC serotypes, to characterize the clinical course and to examine environmental aspects. 95 children with a diagnosis of HUS were evaluated in Germany and Austria. Diarrhea, which was bloody in 67%, was reported in 97% of patients. Oligo-/anuria occurred in 76% of patients, of which 63% required dialysis. Two patients showed neurological sequelae at the 2-month follow-up, both of them were infected with non-O157:H7 serotypes. Case fatality in the acute stage was 3/95, in two of these patients EHEC was isolated. Stool and serum specimens were analyzed for the presence of EHEC and antibodies against O157 lipopolysaccharide (LPS). Serotype O157:H7 was identified in 36/58 (62%) isolates, 22 strains (38%) belonged to non-O157:H7. Combining stool culture with serology, EHEC infection was documented in 88% of patients, including three patients without diarrhea. Non-O157:H7 serotypes occurred in 77% of children up to 36 months of age and were the most prevalent serotype in children up to 12 months of age.

Procalcitonin is not produced by circulating blood cells.

Abstract: A large number of clinical studies has described procalcitonin (ProCT) as a marker of bacterial infection and a good predictor of disease severity and antibiotherapy efficacy. Nevertheless, the mechanism of ProCT synthesis remains unclear. The aim of this study was to demonstrate potential ProCT production by peripheral blood mononuclear cells as is the case for cytokines involved in sepsis. In a whole blood model, LPS (10 μg/ml) stimulation on blood samples from healthy volunteers (n=14) was tested. Early (TNF-α and IL1-β) and late (IL-6 and IL-8) cytokines were produced in large amounts in contrast to the absence of ProCT. Additional experiments with nitric oxide or detection of intra-cellular ProCT (cell lysis, flow cytometry) had negative results. It was concluded that ProCT is not produced in this model. Data are still needed to investigate the cellular origin of ProCT in order to better define its clinical usefulness.

Drug resistance among clinical isolates of frequently encountered bacterial species in central Europe during 1975-1995. Study Group Bacterial Resistance of the Paul-Ehrlich-Society for Chemotherapy.

Abstract: A multicenter study for monitoring antimicrobial drug resistance in clinical isolates of the familyEnterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus andEnterococcus species in central Europa conducted by the Study Group Bacterial Resistance of the Paul-Ehrlich-Society for Chemotherapy has been ongoing since 1975. Between 1975 and 1995 susceptibility data on almost 60,000 bacteria, which were isolated and sampled under a common protocol by laboratories from Austria, Germany and Switzerland, were collected. These bacterial isolates were known by the respective investigators to have caused infections. From 1975 to the mid-80s none of the bacterial species examined showed an increase in resistance. The frequency of resistance in klebsiellae andStaphylococcus aureus to some antibiotics even declined. In 1990 and particularly in 1995, a clear increase in resistance for a number of antibiotic-organism pairs was observed. Resistance rates of fluoroquinolones increased in all species under investigation. InEscherichia coli the increase of resistance to ampicillin, co-trimoxazole and gentamicin was remarkable. Resistance to imipenem increased inP. aeruginosa. Resistance to cephalosporins, on the other hand, remained largely unchanged in gram-negative bacilli. Between 1990 and 1995, the prevalence of oxacillin resistance increased from 1.7 to 12.9% inS. aureus and from 15.8 to 55.8% in coagulase-negative staphylococci, whereas staphylococcal and enterococcal resistance to glycopeptides was still rare.

Occurrence of extended-spectrum betalactamases (ESBL) in Dutch hospitals.

Abstract: The prevalence of ESBL was determined among isolates of Escherichia coli (n = 571) and Klebsiella spp. (n = 196) collected during a 1-week study period in 8 university and 3 large regional laboratories all over the Netherlands. 18 isolates were positive for at least one of the screening tests used, i.e., VITEK-ESBL, E-test ESBL and MIC ratio of ceftazidime/ceftazidime-clavulanic acid, cefotaxime/cefotaxime-clavulanic acid. In 5 of these 18 putative ESBLs no betalactamase production was detectable. A TEM type was found in three E. coli and two Klebsiella spp. An SHV type was present in five Klebsiella spp. In one E. coli and one Klebsiella pneumoniae both enzymes were present. In one Klebsiella oxytoca neither of the two enzymes was present. Using PCR for both ESBL TEM and ESBL SHV, an SHV ESBL was found in one E. coli and four Klebsiella isolates. The mutations at position 238 and 240 were already described. In one E. coli isolate a TEM ESBL was found with three mutations, at position 21, 164 and 265. These mutations were already described in other ESBLs but not in this combination suggesting a new TEM ESBL. The overall prevalence of ESBL producing E. coli and Klebsiella spp. was less than 1% (6 out of 767).

Drug resistance in intensive care units.

Abstract: Intensive care units (ICUs) are generally considered epicenters of antibiotic resistance and the principal sources of outbreaks of multi-resistant bacteria. The most important risk factors are obvious, such as excessive consumption of antibiotics exerting selective pressure on bacteria, the frequent use of invasive devices and relative density of a susceptible patient population with severe underlying diseases. Infections due to antibiotic-resistant bacteria have a major impact on morbidity and health-care costs. Increased mortality is not uniformly shown for all of these organisms: Methicillin-resistantStaphylococcus aureus (MRSA) seems to cause significantly higher mortality, in contrast to vancomycin-resistant enterococci (VRE). Therefore it is essential to diminish these potential risk factors, especially by providing locally adapted guidelines for the prudent use of antibiotic therapy. A quality control of antimicrobial therapy within a hospital, and especially within the ICU, might help to minimize the selection of multidrug-resistant bacteria. The restricted use of antimicrobial agents in prophylaxis and therapy has also been shown to have at least temporal effects on local resistance patterns. New approaches to the problem of drug resistance in ICUs are badly needed.

Seroprevalence of dengue, chikungunya and Sindbis virus infections in German aid workers.

Abstract: Vector-borne virus infections were studied in 670 German overseas aid workers who had spent an average of 377 months in tropical areas of Africa and Asia Antibodies to dengue viruses (DEN) were detected by indirect immunofluorescence assay in 43/670 (64%) aid workers Of these 43, 41 (953%) were also positive for antibodies to dengue by haemagglutination inhibition assay The highest seroprevalence was in aid workers returning from Thailand (194%), Benin (148%) and Burkina Faso (92%) Antibodies to chikungunya virus (CHIK) were detected in 9/670 (13%) aid workers, and the highest seroprevalence to anti-CHIK IgG was in aid workers who had resided in Benin (57%) and Thailand (55%) Antibodies to Sindbis virus were detected only in 1/670 (01%) aid worker who had been to Zambia Vector-borne virus infections, especially DEN, pose a health risk for aid workers

Azithromycin: single 1.5 g dose in the treatment of patients with atypical pneumonia syndrome--a randomized study.

Abstract: An open comparative study was undertaken in order to assess the efficacy and safety of a single dose of azithromycin in the treatment of community-acquired atypical pneumonia. A total of 100 adult patients with atypical pneumonia syndrome were randomized to receive 1.5 g of azithromycin as a single dose, or 500 mg once daily for 3 days. The presence of Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci, Coxiella burnetii, and Legionella pneumophila infection was diagnosed by serological tests. Control clinical examinations were performed 72 h, 10-12 days and 4 weeks after treatment initiation. Among 96 patients (48 in each group) who were evaluable for clinical efficacy M. pneumoniae infection was confirmed in 24, C. pneumoniae in nine, C. psittaci in five, C. burnetii in six, and L. pneumophila in five. Forty-seven patients (97.9%) in each group were cured. Side effects were observed in two patients in the single-dose group, and one patient in the 3-day group. In conclusion, a single 1.5 g dose of azithromycin may be an alternative to the standard 3-day azithromycin regimen in the treatment of outpatients with atypical pneumonia syndrome.

Leukocytopenia, thrombocytopenia and fever related to piperacillin/tazobactam treatment--a retrospective analysis in 38 children with cystic fibrosis.

Abstract: Bone marrow suppression is an important adverse reaction to most betalactam antibiotics Recently it was suggested that piperacillin/tazobactam (PT) also may cause bone marrow toxicity We retrospectively analyzed 100 IV antibiotic treatment courses (mean duration 125 days) in 38 patients (median age 14 years) with cystic fibrosis (CF) who were treated in our hospital Of the patients receiving PT (84%), 6 patients (1875% of PT-treated patients, 103% of PT treatment courses) developed fever, malaise and headache during treatment without signs of acute infection In one patient definite thrombocytopenia and neutropenia, in two others a milder decrease in leukocyte and thrombocyte counts was observed after the onset of fever The events were time- and dose-dependent occurring between day 11 and 15 of treatment Treatment courses lasted longer (142 vs 113 days; p < 005) and patients had received a higher cumulative dose of PT (4919 ± 1975 mg/kg bw vs 3161 ± 1635 mg/kg; p < 002, Student's t-test) in the affected group than in the unaffected group After discontinuation of PT, fever subsided within 24 h and blood cell counts normalized We hypothesize that these fever episodes and changes of blood parameters are related to PT therapy

Basic aspects of the pathogenesis of staphylococcal polymer-associated infections.

Abstract: Staphylococci are among the most frequently isolated microorganisms in clinical microbiology laboratories. Reports on surveillance data taken from the National Nosocomial Infections Surveillance System during the late 1980s and early 1990s indicated that Staphylococcus aureus, as well as coagulase-negative staphylococci (CONS), arc among the five most commonly reported pathogens in hospitals conducting hospital-wide surveillance [1,2]. S. aureus is one of the most feared pathogens, causing severe morbidity and often rapidly fatal infections. Infections due to these gram-positive cocci are often acute and pyogenic and, if untreated, may spread to surrounding tissue or, via bacteremia, to metastatic sites in other organs [3, 4]. CoNS are distinguished from S. aureus by their inability to produce free plasma coagulase. Currently, out of more than 30 coagulase-negative staphylococcal species, 12 are found mainly in specimens of human origin [5]. Because of their high prevalence on human skin and mucous membranes and their relatively low virulence, one of the major problems facing the laboratory is to distinguish clinically significant, pathogenic strains of CoNS from concomitant strains [5]. In recent years staphylococci, particularly CONS, have become important nosocomial pathogens and frequently cause infections associated with implanted foreign bodies. A wide spectrum of bacteria can be involved in this type of infection, however, staphylococci are by far the most frequently isolated group of bacteria. A battery of virulence factors involved in the pathogenesis of polymerassociated staphylococcal infection has been defined and characterized during the last few years and these findings will be presented in the following section.

Selective pressure by antibiotics as feed additives.

Abstract: Antibacterial substances are used in considerable amounts as growth promoters in animal husbandry. There are, however, incalculable risks for human health resulting from the use of particular feed additives. Even 30 years ago the detection of transferable antibiotic resistance inEnterobacteriaceae led to the demand that antibiotics used in human chemotherapy, or for which cross-resistance against human therapeutics has been demonstrated, should be prohibited as growth promoters. The application of molecular methods to typing and characterization of bacteria and their resistance genes has provided more concise evidence for the transfer of antibiotic resistance among animal husbandry and humans as to resistance to glycopeptides (vanA gene cluster) and to streptogramins (satA).

Human parvovirus B19-associated disease in bone marrow transplantation.

Abstract: Human parvovirus B19 can persist in immunocompromised patients and may produce severe clinical illness. In this retrospective study the incidence of B19-associated infections in bone marrow transplant patients was investigated. During 1 year 60 patients received bone marrow grafts (eight autografts and 52 allogeneic transplantations). In case of early onset, atypical or steroid-resistant erythrodermia the patients' blood and/or tissue specimens were screened for B19 infection by polymerase chain reaction (PCR). Additionally, specimens of patients with severe organ failure were tested. A total of 64 PCRs was performed in 27 patients. Seven patients with erythrodermia and one with vulvovaginitis proved to be PCR positive. In patients with organ failure B19 DNA was detected in the myocardium and liver. The incidence of B19 infections in this cohort was 15% and the B19-associated mortality rate 7%. In conclusion, parvovirus B19-associated infections may be more common in immunocompromised patients than previously anticipated.

High prevalence of HCV-RNA in the saliva cell fraction of patients with chronic hepatitis C but no evidence of HCV transmission among sexual partners

Abstract: The aims of this study were to evaluate the prevalence of HCV-RNA in different fractions of saliva taken from patients with chronic hepatitis C, to establish whether virologic parameters or disease severity exert any influence on the detectability of HCV-RNA in saliva, and to evaluate the prevalence of HCV infection in partners of HCV-infected subjects with respect to the presence of HCV-RNA in saliva. Sera samples and different fractions of saliva (whole saliva, surnatant, and cell fraction) from 48 subjects (45 with chronic hepatitis C and three healthy anti-HCV+ carriers) were examined for HCV-RNA by RT nested PCR and DEIA hybridization. HCV-RNA-positive sera were also tested for genotype and viral titer (bDNA2 method). Twenty-seven stable sexual partners (25 females and 2 males) were screened for anti-HCV antibodies at least twice over a minimum of 12 months, HCV-RNA was detected in the sera of 39/45 patients and of 22/39 viremic patients. In all of the latter, the presence of HCV-RNA was restricted to the cell fraction. Viral titer was significantly higher in patients with HCV-RNA in saliva than in those without (12.3×106 versus 4.6×106 eq/ml, P<0.01). HCV-RNA positivity was unrelated to genotype, duration of disease, Hepatitis Activity Index scores or transminase levels. Anti-HCV was positive in one of 13 sexual partners of patients with HCV-RNA in saliva and in 1/14 of those without (P=NS). In conclusion, HCV-RNA is detectable in the cell fraction of saliva in a high proportion of highly viremic patients with chronic hepatitis C, but its presence does not seem to be associated with an increased risk of HCV transmission among sexual partners.

Drug resistance in Plasmodium falciparum malaria.

Abstract: Four classes of drugs are reviewed: blood schizontocides acting only on the hemoglobin-digesting blood stages, the antifolates which attack tetrahydrofolate synthesis in all the growing stages, antimitochondrials affecting synthesis and electron transport, and 8-aminoquinolines which interfere with redox processes. Drug efflux via a multidrug resistance membrane protein, and the production of a protein competing with the drug for the target hemin are thought to be responsible for resistance to blood schizontocides. Structural changes in target enzymes are responsible for easily-developed resistance to antifolates and antimitochondrials. The judicious use of drug combinations can help to avoid development of resistance and combat resistant infections, but new drugs are urgently needed.

Thrombotic microangiopathies and HIV infection: report of two typical cases, features of HUS and TTP, and review of the literature.

Abstract: Haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are thrombotic microangiopathies increasingly reported in patients with HIV infection. However, characteristic features of thrombotic microangiopathies associated with HIV disease have not been defined yet. The typical courses of HUS and TTP in two patients are presented. The data as well as the analysis of cases published in the literature demonstrate the association of thrombotic microangiopathies with late-stage HIV disease. Moreover, differences between HUS and TTP can be detected. Patients with HUS present with more severe immunologic deterioration. Although clinical symptoms are fewer, HUS implicates a very poor prognosis. Life expectancy rarely exceeded 1 year after diagnosis. HUS and TTP should therefore be added to the international AIDS classification.

Determination of the silver ion release from polyurethanes enriched with silver.

Abstract: The Erlanger silver catheter was developed in order to reduce the risk of infection from long-term catheters by means of silver ions, which are known to have antibacterial properties. This is achieved by incorporating silver into polyurethane catheters by means of a special procedure. The aim of this materials science study was to verify the release of silver ions from the polyurethanes. Static experiments were carried out following the usual norms. Clinically relevant dynamic experiments, which were designed and constructed at this institute, were also performed. The eluates from both experiments were analyzed by anodic stripping voltammetry. Polyurethanes filled with silver, as used in the Erlanger silver catheter, release silver in static as well as in dynamic experiments. If the experimentally determined releases are converted to the usual catheter length of 30 cm, the release is about 0.1 microgram/l. This lies in the order of concentrations that have been reported in the literature to be antibacterial.

Antimicrobial susceptibility of 1,422 Haemophilus influenzae isolates from respiratory tract infections in Spain. Results of a 1-year (1996-97) multicenter surveillance study. Spanish Surveillance Group for Respiratory Pathogens.

Abstract: A Haemophilus influenzae multicenter antimicrobial susceptibility surveillance was carried out. An overall beta-lactamase production rate of 25.7% was found, with significant differences between hospitals ranging between 7.9 and 47.9%. Presumable intrinsic resistance was found in 4.6% of strains. No differences in susceptibility were observed between beta-lactamase positive and beta-lactamase negative strains for all antibiotics, except for penicillin, amoxicillin and cefaclor. A higher prevalence of resistance was found for clarithromycin vs azithromycin (22.6 vs 0.7%). Differences in all these factors make surveillance essential as a guideline for empiric treatment in community-acquired respiratory tract infections.

Seroprevalence and disease association of antineutrophil cytoplasmic autoantibodies and antigens in HIV infection.

Abstract: This prospective study was designed to determine the role of antineutrophil cytoplasmic autoantibodies (ANCA) in HIV-infected patients. Immunofluorescence tests (IFT) and enzyme-linked immunosorbent assays (ELISA) were applied to sera of 199 consecutive outpatients. In the IFT 20% were positive. An atypical ANCA pattern was demonstrated in 67% of these, 33% revealed a perinuclear staining (pANCA). Specific ELISA revealed proteinase 3 (n = 2), myeloperoxidase (n = 1), lysozyme (n = 2), lactoferrin (n = 1), cathepsin G (n = 1), and human leukocyte elastase (HLE, n = 6). The target antigen remained unidentified in 26 patients. Perinuclear ANCA-positive patients showed atypical antigens in eight of 13 cases; all six patients with anti-HLE revealed a pANCA pattern. The antigens of atypical ANCA-positive patients remained unidentified in 21 of 26 (81%) cases. No signs of vasculitis were present in the ANCA-positive patients. ANCA are frequently found in the sera of HIV-positive patients. They bind to a variety of antigens. No correlation was found between ANCA positivity and autoimmune or opportunistic diseases.

Catheter-associated primary bloodstream infections: epidemiology and preventive methods.

Abstract: The incidence of catheter-associated primary bloodstream infections (BSIs) in Germany as defined by the CDC (Centers for Disease Control) has been determined on the basis of (a) a national prevalence study in a representative sample of 72 hospitals (NIDEP*), and (b) an incidence study in which data about the use and duration of insertion of central venous catheters (CVC) and of catheter-associated BSI were collected from 25 intensive-care units (ICUs) participating in the hospital infection surveillance system (KISS+) and analyzed. The first study showed primary bloodstream infection to be the fourth most frequent nosocomial infection at 8.3% of all nosocomial infections. With an ICU prevalence of 2.1%, primary BSI comprises 12.8% of all nosocomial infections observated in ICU patients. The second study showed a 60.4% prevalence of CVC use in German ICUs. An analysis of 55,400 CVC days in 14,988 ICU patients in the KISS hospitals yielded 2.2 CVC-associated BSIs per 1,000 CVC days (CI95 1.8–2.6). The rates of CVC-associated BSI on individual hospital wards were very variable and indicates a reduction potential. A reduction in the number of infections of about one-third would prevent 1,000–1,400 deaths due to CVC-associated BSI annually as well as about 40,000 to 60,000 extra days of hospital stay and the associated costs.

Endocarditis due to Aerococcus urinae: diagnostic tests, fatty acid composition and killing kinetics.

Abstract: Two cases ofAerococcus urinae endocarditis are reported. The organism is not included in any database of commercial identification systems at this time. Formation of tetrades and positive reactions for leucine arylamidase and beta-glucuronidase pointed strongly toA. urinae. The cellular fatty acid pattern was similar to that ofAerococcus viridans, with predominantly C16∶0, C18∶1ω9c and C18∶0; the presence of C18∶1ω7t differentiated our isolates fromA. viridans and can support the diagnosis ofA. urinae. Furthermore, susceptibility to penicillin but resistance to cotrimoxazole represents a pattern opposite to that ofA. viridans. Minimal inhibition concentrations of gentamicin and netilmicin were≤64 mg/l but those of tobramycin were≥256 mg/l. Penicillin combined with either gentamicin or netilmicin showed distinct synergy in killing kinetics. These combinations seem to be the appropriate regimen to treatA. urinae endocarditis.

Biocompatibility testing of a new silver-impregnated catheter in vivo.

Abstract: The purpose of this investigation was to compare the local effects of polyurethane (Tecothane®) and silicone tubes with or without silver impregnation in rats. Bacterial colonization or infection of the exit site and/or tunnel were documented and interpreted. All tubes were placed subcutaneously or percutaneously in the neck of 41 Sprague-Dawley rats and guided beneath the dorsal muscles into the peritoneal cavity. The incidence of bacterial abscesses along the implanted tubes was evaluated daily. After 90 days, or earlier if sepsis developed, the animals were killed painlessly and various organs and tissues from the entry site and the catheter tunnel examined histologically. In the group where polyurethane tubes were placed percutaneously, there was no difference in the frequency of abscesses between silver-impregnated and non-impregnated tubes (5/6 with and 5/7 without silver). The only difference noted was in the group with percutaneously placed silicone tubes between those with and without silver. Abscesses only occurred in 2/4 animals in the silver group and in 5/5 animals in the control group. Histological examination showed no difference in either group between infectious and foreign body reactions. Silver particles in subcutaneous, muscle and peritoneal tissue could not be demonstrated.

Neonatal nosocomial infection surveillance: incidences by site and a cluster of necrotizing enterocolitis.

Abstract: Nosocomial infection (NI) was prospectively studied in hospitalized neonate during a 10-month period. The Centers for Disease Control (CDC) criteria (some specified for neonates) were used for surveillance. Forty-nine of 677 infants experienced 73 episodes of NI. The overall incidence was 10.8 NI/100 patients and 6.5 NI/1,000 patient days. The average monthly NI number did not correlate with patient load. Very low birth weight (VLBW) infants showed a higher NI incidence (81.8 NI/100 patients and 11.1 NI/1,000 patient days), also elevated if adjusted for their inherently longer neonatal intensive care unit (NICU) stay. The most common NI sites in the VLBW stratum were sepsis and necrotizing enterocolitis (NEC), the latter occurring in a seasonal cluster. It can be concluded that surveillance for NIs should focus on VLBW infants and include the evaluation of NEC, as it behaves like a nosocomial disease.