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Biomedical subjects

M Arpi

Publications and source records attributed to M Arpi.

44 records · Page 3Linked to original sources
PubMed1987

Comparative in vitro activities of pefloxacin, ofloxacin, enoxacin and ciprofloxacin against 256 clinical isolates.

The antibacterial activity of four new fluoroquinolone carboxylic acids, pefloxacin, ofloxacin, enoxacin and ciprofloxacin, against 256 clinical isolates was investigated by means of an agar dilution method. Generally, all quinolones tested had a high activity against Gram-negative bacteria. More than 90% of Enterobacteriaceae strains were inhibited by a quinolone concentration of 0.4 microgram/ml. Also strains usually resistant to conventional beta-lactam antibiotics, and sometimes to third-generation cephalosporins, like Enterobacter spp., Serratia spp, and Yersinia spp. were susceptible to the tested quinolones. Ciprofloxacin was 5 to 25-fold more potent on a weight basis against Enterobacteriaceae than the other quinolones. Neisseria meningitidis, Neisseria gonorrhoeae, and Haemophilus influenzae were extremely susceptible to the new quinolones. Ciprofloxacin was about 10 times more potent against Pseudomonas aeruginosa than the other quinolones, and was the only quinolone that was sufficiently active against all tested P. aeruginosa strains (MIC less than or equal to 0.4 microgram/ml). The activity against Gram-positive bacteria was considerably lower. All the quinolones investigated had an acceptable activity against many of the methicillin-sensitive and methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci. The majority of the Streptococcus spp. tested was quinolone-resistant, and was Listeria monocytogenes. Generally, it was evident that ciprofloxacin was more potent on a weight basis than the other quinolones, but this difference was counterbalanced by a higher achievable serum concentration for ofloxacin. Some of the investigated fluoroquinolones might constitute valid therapeutical alternatives to beta-lactam antibodies and aminoglycosides in the treatment of serious bacterial infections.

Anti-Bacterial Agents↗
PubMed1986

Antibiotic susceptibility of Haemophilus influenzae isolated from cerebrospinal fluid and blood.

The emergence of ampicillin and chloramphenicol resistant Haemophilus influenzae type b in Denmark has created demands for alternative treatments of serious infections with H. influenzae. In this study 102 strains of H. influenzae recovered from cerebrospinal fluid (85) and blood (17) were tested for susceptibility to ampicillin, piperacillin, erythromycin, rifampicin, chloramphenicol, cefuroxime, cefotaxime, ceftazidime, ceftriaxone, moxalactam, aztreonam, and netilmicin by means of the agar dilution method. The majority (97%) was H. influenzae type b and of these strains 94% belonged to biotype I. Nine of the investigated strains were beta-lactamase producers. Ceftriaxone and cefotaxime were the most active agents (MIC90 less than or equal to 0.025 microliter/ml) followed by moxalactam and aztreonam (MIC90 = 0.1 microgram/ml). Except for ampicillin and piperacillin, the MIC was similar for beta-lactamase producers and non-producers. Several of the investigated antibiotics, especially some of the third generation cephalosporins, might constitute valid therapeutical alternatives to conventional drugs in the treatment of severe H. influenzae infections.

Anti-Bacterial Agents↗
PubMed1986

In vitro studies of the synergism of piperacillin and netilmicin against blood culture isolates.

The purpose of this study was to evaluate the in vitro synergism between piperacillin and netilmicin against microorganisms isolated from Danish patients with septicemia and to examine the influence of inactivation of piperacillin among these bacteria on the synergy results. A total of 132 stains was examined: Escherichia coli 20, indole-positive Proteus 17, Klebsiella pneumoniae 18, Enterobacter cloacae 20, Pseudomonas aeruginosa 20, Staphylococcus aureus 20, and coagulase-negative staphylococci 17. Synergy testing was performed by checkerboard titration in microtiter trays. The ability of the strains to inactivate piperacillin was examined by the clover-leaf test. Synergism was found for 52% of the strains and partial synergism for 32%. Antagonism was not found. Of the piperacillin-resistant strains synergism could be demonstrated in 80% compared with 33% of the piperacillin-susceptible strains (p less than 0.001). No significant correlation was seen between the results of the synergy test and the results of the susceptibility test to netilmicin. The frequency of piperacillin inactivation according to the clover-leaf test was significantly higher among the strains with synergism than among all the others (p less than 0.02). The combination of piperacillin and netilmicin gave good results concerning the in vitro synergism. This synergism was probably sometimes caused by netilmicin disturbing the bacterial production of piperacillin-inactivating proteins.

Bacteria↗
PubMed1986

Bacteremia following transurethral instrumentation. The predictive value of a serum bactericidal activity test.

The bacteremic rate following transurethral instrumentation and the possibility of a serum bactericidal activity test to predict which patients that were at an increased risk of developing bacteremia was evaluated. Of 33 investigated patients, all elderly men, 14 underwent transurethral prostatic resection, 14 cystoscopy and 5 urethrotomy. None of the patients received prophylactic antibiotic treatment. The majority (97%) of the patients had bacteria isolated from the urinary tract before the instrumentation. Gram-positive cocci accounted for about two thirds (64%) and Gram-negative rods for about one third (31%) of all isolates. The most frequent species isolated were coagulase negative staphylococci (29%), Streptococcus faecalis (19%) and Klebsiella pneumoniae (12%). The bacteremic rate was 21%. None of the patients developed septicemia. Forty-four per cent of the patients with greater than or equal to 10(5) colony forming units/ml (cfu/ml) in urine developed bacteremia compared with 8% in patients with a sterile urine or less than 10(5) cfu/ml in urine (p less than 0.05). The urethral/prostatic flora was the source of bacteremia in at least one patient. Eighty-one per cent of the isolated strains were serum resistant. About half (54%) of the Gram-negative rods were more or less sensitive against actual, fresh patient serum. All Gram-positive cocci were resistant. There was no difference in the serum sensitivity between bacteria isolated from bacteremic patients and non-bacteremic patients. In conclusion, this study confirmed the relative high risk of developing bacteremia following transurethral instrumentation, especially if the urine is infected.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

A comparison of a conventional and a radio-metric examination of clinical blood cultures with respect to recovery rate and detection time of microorganisms.

The results from a comparative investigation of two different blood culture systems with respect to the recovery rate and the detection time are presented. Patients from whom enough blood volume could be drawn to fill two or more Venoject tubes, were consecutively included in the study. The blood was equally divided between our conventional system (4 tubes of nutrient broth, 4 tubes of semisolid nutrient agar and 4 tubes of semisolid thioglycollate agar) and a radiometric system, Bactec (one aerobic and one anaerobic vial). From a total of 1252 blood cultures, one or both systems detected 170 positive cultures (13.6%) from 140 patients. Of a total of 127 positive blood cultures representing bacteremia, the dominating species were Escherichia coli and Staphylococcus aureus, accounting for 31 and 27% respectively. The radiometric system detected 95% and the conventional system 82% of all clinically relevant isolates (p less than 0.001). Especially E. coli and Klebsiella pneumoniae were detected more frequently in the radiometric system. The radiometric system had a shorter average detection time than the conventional system (1.0 versus 1.7 days). This may have therapeutical and prognostical consequences for patients with bacteremia. One fourth of all positive blood cultures was due to contamination. The majority of the contaminants, mainly coagulase negative staphylococci, were found in the radiometric system, as were false positive cultures. This comparative study demonstrated positive and negative sides of both systems tested.

Bacteriological Techniques↗
PubMed1984

The clinical significance of Staphylococcus aureus bacteriuria.

To investigate the rate of occurrence, clinical presentation, predisposing factors and frequency of secondary bacteremia 132 patients with significant Staphylococcus aureus bacteriuria were reviewed retrospectively. Staphylococcus aureus accounted for 3.3 per cent of all positive urine cultures. Most patients were elderly men. The most important predisposing factors in the urinary tract were indwelling catheters (63 per cent), obstruction (56 per cent) and instrumentation or surgery (43 per cent). Bacteremia developed secondary to bacteriuria in all 11 patients (8.3 per cent). For that reason Staphylococcus aureus bacteriuria should be regarded as a hazardous condition, especially in patients with predisposing factors in the urinary tract.

Adult↗