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M Arpi

Publications and source records attributed to M Arpi.

At least 37 records · Page 2Linked to original sources
PubMed1993

Comparison of detection speed and yield in BACTEC NR-860 and Roche BCB blood culture systems.

Detection speed and yield were compared between BACTEC NR-860 and Roche BCB blood culture systems. From a total of 1,550 paired blood cultures inoculated with the same volume of blood, 161 (10.4%) grew 180 organisms from 140 adult patients. Sixty-six percent of the isolates were clinically significant. The BACTEC system detected more clinically significant isolates than the BCB system, 91% vs 76% (p < 0.01), especially Enterobacteriaceae. In 39 paired blood cultures, 42 significant organisms were detected at different times in the two systems. The vast majority (93%) were detected first (on average 1 day faster) by the BACTEC system (p < 0.05), especially Escherichia coli and streptococci. Generally, detection times were shorter in the BACTEC system. Three fourths (76%) of all significant organisms were detected within the first incubation day as compared to less than half (42%) in the BCB system (p < 0.001). Generally, the agitated aerobic resin medium BACTEC 26 Plus had the fastest detection and highest yield in our study. The contamination rate, below 2% in both systems, was acceptable. The BACTEC NR-860 system with resin-containing media proved to be a reliable, sensitive and fast blood culture system, which deserves further investigation.

Adult↗
PubMed1992

[Toxic shock syndrome. A case of a child with burns].

A case of the toxic shock syndrome (TSS) in a burnt (scalded) child is presented. TSS is a condition most frequently associated with menstruating women using tampons. In recent years, however, increased knowledge of the syndrome has led to an increase in the number of reported cases associated with other clinical situations. The non-menstrual cases are most frequently observed in young persons many of whom are children. TSS is due to infection with toxin-producing S. aureus. TSS-toxin-1 is apparently the most important among toxins. The fatality rate has been reported to be as high as 15%, so recognition of the syndrome and institution of the correct treatment are of utmost importance. By means of an easy and rapid test, it is possible to detect if the strain of S. aureus is TSST-1-producing. The test is now available and employs passive latex agglutination. The sensitivity and specificity are high and, if clinical signs of TSS are present, a positive test result will support the diagnosis in 94% of alle positive cases.

Burns↗
PubMed1992

Comparison of detection speed and yield in agitated and non-agitated aerobic blood culture bottles.

The influence of agitation on detection speed and yield was evaluated in 7,033 paired, identical aerobic blood culture bottles (Media Department, Statens Seruminstitut, Copenhagen, Denmark). One bottle was agitated and the other was incubated stationary. Of a total of 943 organisms isolated in aerobic blood culture bottles, 74% were clinically significant. No difference in the total yield of significant organisms was observed between agitated and non-agitated bottles. In the evaluation of detection speed, only cultures where organisms were isolated from both bottles, but at different times, were included, to ensure that no other factors influenced the result. Staphylococci, Pseudomonas spp., and Candida spp. were detected significantly faster in agitated bottles, on average 0.5-1 day earlier (p < 0.05), and in the majority of the cases within the first incubation day. These species are frequently found and are important causes of severe generalized infections, especially in immunocompromised patients, where early detection is of great importance. The detection principle in agitated bottles in our system, darkening of blood, proved to be an easy, reliable, and fast method to detect positive aerobic blood cultures, which could probably lead to increased automation.

Aerobiosis↗
PubMed1991

Should aerobic blood cultures be shaken intermittently or continuously?

Stationary incubation of aerobic blood cultures was compared with intermittent shaking in aerobic Vacutainer 2630 bottles with agar slants during the first 24 h, and was simultaneously compared with the continuously shaken aerobic Bactec 6A bottles as a reference system. Intermittent shaking did not significantly increase or decrease the seven days yield of the Vacutainer bottles as compared with the continuously agitated Bactec 6A bottles. When one of 604 paired Vacutainer bottles was agitated for eight h and the other incubated stationary, the speed of growth detection was significantly greater in the agitated bottle (p less than 0.001), but significantly less than with continuously agitated Bactec 6A bottles (p less than 0.001). Agitation for 14 h showed the same pattern of detection speed. These results suggest that it is desirable initially to agitate aerobic blood cultures either intermittently or continuously.

Aerobiosis↗
PubMed1990

Comparison between Bactec Nr. 660 and a conventional 12-tube blood culture system.

The detection power of the automated blood culture system Bactec NR 660, based on infrared detection of carbon dioxide in an agitated aerobic medium and a non-agitated anaerobic medium, was compared with that of our conventional 12-tube blood culture system. Of 1685 paired blood cultures, 258 (15.3%) were positive in one or both systems. Clinically relevant isolates were found in 11.5%. The dominating species were Escherichia coli(41%), followed by Staphylococcus aureus(14%) and Klebsiella spp.(8%). The Bactec system detected 178 (10.6%) and the 12-tube system 157 (9.3%) clinically relevant microorganisms after seven days' incubation. Significantly more clinically relevant isolates were detected by the Bactec system alone as compared with the conventional system alone (40 versus 19, p less than 0.01). The detection time was significantly shorter in the Bactec system for all isolates and for E. coli and S. aureus separately (p less than 0.01). 1.8% of the isolates in the Bactec system and 2.1% in the 12-tube system were considered clinically non-relevant contaminants.

Autoanalysis↗
PubMed1989

Importance of blood volume cultured in the detection of bacteremia.

The influence of the volume of blood cultured on the rate of detection of bacteremia was evaluated in a routine 12-tube blood culture system using 1693 samples from 1502 patients. Blood samples were drawn simultaneously into two transport tubes. The blood volume cultured was the only varying parameter. Generally, 17% more cultures with clinically significant microorganisms (both Enterobacteriaceae and gram-positive cocci) were found when blood from two instead of one tube was used (in most cases comparing 13-16 ml of blood with 6.5-8 ml). Of the most prevalent species, the maximum average extra yield was observed for Staphylococcus aureus (26%) followed by Escherichia coli (16%) and Streptococcus pneumoniae (12%). In adults most cases of bacteremia are low-grade. The grade of bacteremia in our patient population was on average as low as 0.25 CFU/ml blood. Therefore, all patients suspected of having bacteremia should have the benefit of a sufficient volume of blood cultured. Since the volume of blood cultured seems to be the single most important factor in the detection of bacteremia, it is imperative that the volume is the same in comparative studies of different blood culture systems.

Bacteria↗
PubMed1988

Antibiotic therapy of meningitis caused by ampicillin-resistant Haemophilus influenzae in Denmark and Greenland 1981 to 1987.

A survey was performed in Denmark and Greenland in order to determine whether the current recommendation of ampicillin (400 mg/kg/day) for initial treatment of purulent meningitis is appropriate. Data obtained 1981-1987 in an ongoing nationwide programme for surveillance of ampicillin-resistant Haemophilus species was analysed, and patient records of 21 cases of meningitis caused by ampicillin-resistant Haemophilus influenzae strains (17 in Denmark, 4 in Greenland) reported in the period 1981-1987 were reviewed. In Denmark the overall rate of ampicillin-resistant Haemophilus influenzae was estimated to be approximately 2% for the study period, and the average rate of resistant isolates from spinal fluid was 5.2% (range 0-12.3%). The incidence of meningitis caused by ampicillin-resistant Haemophilus influenzae strains remained low in the Danish population (around 0.05/100,000/year) except for a peak in 1985. The overall mortality rate of Haemophilus influenzae meningitis for the study period was 2.4%, which was the same as before 1980. In Greenland the actual number of cases of meningitis caused by ampicillin-resistant Haemophilus influenzae was small, but the incidence was at least 40 to 80 times higher than in Denmark with a high mortality rate (50%). These observations prompted revision of the antibiotic regimen in Greenland, whereas the regimen was considered appropriate in Denmark.

Adult↗
PubMed1988

Comparative analysis of two blood culture systems (Isolator and a 12-tube system) by cumulative differences in detection power at different times during incubation.

A lysis-centrifugation blood culture system (Isolator) and a conventional system (4 tubes of nutrient broth, 4 tubes of semisolid agar, and 4 tubes of thioglycollate agar) were compared after different lengths of incubation by cumulative scoring of differences in detection power. After the first half day of incubation, the Isolator system was already significantly faster in detecting isolates of clinical significance (15 vs. 4, P = 0.02). Maximum difference in first or only detection system was seen after two days of incubation and was based on an overall superior detection of Staphylococcus aureus (11 vs. 0, P = 0.001), and an earlier detection of Enterobacteriaceae (30 vs. 13, P = 0.01) in the Isolator system. On the contrary, the detection of Streptococcus pneumoniae was significantly inferior in the Isolator system (0 vs. 10, P = 0.002). The earlier finding of clinically significant microorganisms in the Isolator system certainly contributes to good patient-care. A drawback of the Isolator system was the finding of clinically insignificant coagulase-negative staphylococci in 11%, compared with 1% in the conventional system. This led to a considerable waste of time and materials in the laboratory. The comparison of the two blood culture systems, based on statistical analysis of cumulative differences in detection power, expressed as the earliest or only findings, gives the optimal information, and is in our opinion the clinically most relevant comparison.

Bacteria↗
PubMed1988

Time-kill studies and synergy testing of broad-spectrum antibiotics against blood culture isolates.

Time-kill studies and synergy testing were performed with blood culture isolates from 80 patients with septicemia. Ten isolates each of Escherichia coli, Proteus mirabilis, indole-positive Proteus, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Staphylococcus aureus, and coagulase-negative staphylococci were included. The isolates were tested against netilmicin, piperacillin, cefoxitin, cefuroxime, and cefotaxime, alone and in different combinations. Cefotaxime was the most active agent against Enterobacteriaceae, whereas netilmicin was the most active agent against P. aeruginosa and staphylococci. The most active antibiotic combinations were netilmicin-cefotaxime and netilmicin-piperacillin, where a synergistic activity was observed in 68 and 61%, respectively. The highest synergistic activity was against Enterobacteriaceae, but the netilmicin-cefotaxime combination also acted synergistically against more than half of the S. aureus isolates. A relatively low synergistic activity was noted against P. aeruginosa. No case of antagonism was observed. Subinhibitory concentrations of netilmicin, in combination with a greater than or equal to MIC concentration of one of the tested beta-lactam antibiotics, significantly improved the killing of the isolates. Netilmicin exerted a more rapid and pronounced bacterial reduction than the beta-lactam antibiotics tested.

Anti-Bacterial Agents↗
PubMed1988

Contaminating coagulase-negative staphylococci isolated in a lysis-centrifugation (Isolator) blood culture system. Application of different epidemiological markers for deduction of mode of contamination.

The lysis-centrifugation blood culture system, Isolator, is a promising system with respect to detection of many significant microorganisms, e.g. Staphylococcus aureus and Enterobacteriaceae, as compared with conventional systems. A drawback of the Isolator system is a disturbingly high rate of clinically insignificant, supposedly contaminating coagulase-negative staphylococci, which leads to considerable waste of time and materials in the laboratory. Several sources of these isolates have been proposed (viz. the patient, the ward environment, the laboratory handling, and the plate media). The aim of this study was to pinpoint the origin of these clinically doubtful coagulase-negative staphylococci, using different epidemiological markers, such as species identification, antibiotic susceptibility patterns, phage-types, and plasmid profiles. Plasmid profile analysis proved to be more discriminating than the other techniques and made it possible to conclude that the laboratory handling of the Isolator system was a major source of coagulase-negative staphylococci in this system.

Bacteriological Techniques↗
PubMed1987

In vitro activity of ciprofloxacin against methicillin-susceptible and methicillin-resistant staphylococci.

Ciprofloxacin was found to be active against selected strains of methicillin-resistant as well as methicillin-susceptible Staphylococcus aureus and Staphylococcus epidermidis, having minimal inhibitory concentrations less than 0.8 micrograms/ml with inocula of approximately 10(4) CFU/ml. When killing kinetic studies were done with inocula of approximately 10(6) CFU/ml and various ciprofloxacin concentrations, the killing effect was low (less than 3 log10 in 6 h) and regrowth of the culture was seen after 24 h in at least one Staphylococcus aureus strain. After 48 h incubation, mutants with MICs eightfold that of the parental strain had grown to a number of approximately 10(10) CFU/ml.

Ciprofloxacin↗
PubMed1987

Borrelia meningitis in Denmark.

We studied 23 patients with borrelia meningitis, a tick-borne spirochetosis increasingly recognized in Denmark. The disease showed a seasonal incidence from June to December. Twenty one patients experienced a painful sensory radiculitis, in 17 cases followed by a predominantly cranial mononeuritis multiplex mainly affecting the facial nerve (Bannwarth's syndrome). Three patients had focal CNS involvement in the form of a transverse myelitis, a focal encephalitis and a disseminated leucoencephalopathy, respectively. The CSF showed invariably lymphocytic pleocytosis and elevated spinal protein concentration. Measuring borrelia antibodies in the CSF seemed of higher diagnostic sensitivity than in serum. Penicillin therapy was effective even in cases with focal CNS lesions.

Adolescent↗