In-vitro activity of cefotaxime against clinical isolates of Yersinia enterocolitica biotype 4, serotype 03.
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Biomedical subjects
Publications and source records attributed to P Søgaard.
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We report a case of hematogenous Yersinia enterocolitica coxitis 10 years after hip replacement. Despite extraction of the prosthesis and antibiotic treatment, the infection relapsed. Infections in replaced joints with Yersinia enterocolitica call for long-standing treatment with specific antibiotics.
In ten healthy subjects final gastric emptying of solid food was measured by a new scintigraphic method, employing 99mTc labelled pellets, and compared to a radiologic method, employing food with incorporated barium suspension. Final gastric emptying of solid food, measured by the scintigraphic technique, was 5.2 hours and with the radiographic technique 5.5 hours, with no significant difference. It is concluded that significant information concerning gastric emptying of solid food can be obtained by the radiological method.
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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.
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.
A collection of 138 consecutive isolates from blood primarily identified as Gram-positive, cluster-forming, coagulase-negative cocci was examined by a conventional routine method for identification of clinical isolates of coagulase-negative Staphylococcus and Micrococcus species. The method was based on selected reactions from the Kloos & Schleifer scheme, utilizing the conventional media of Statens Seruminstitut. Double determinations for each isolate were performed by the conventional method. The results were compared with speciation by the commercial micromethods API-Staph and API-Staph-Ident. For control, 31 Staphylococcus and 13 Micrococcus reference strains were included. Of the 31 Staphylococcus spp. (reference strains), the conventional system, API-Staph, and API-Staph-Ident correctly identified 87%, 87% and 81%, respectively. Micrococcus spp. were only identified to genus level by the conventional method as well as by API-Staph. API-Staph-Ident is not designed for Micrococcus identification. Of 138 blood isolates, 121 belonged to the genus Staphylococcus while 17 were Micrococcus spp. S. epidermidis dominated with all three methods, constituting approx. 35% of the isolates tested. In only 57% of the isolates identification by all three methods agreed. The three methods were unable to put a name on 7.5% (conventional method), 10.7% (API-Staph) and 2.5% (API-Staph-Ident) of the isolates. Reproducibility was high with the conventional method (100% for the reference strains and 91% for blood culture isolates) as well as with API-Staph and API-Staph-Ident (88%/81% and 81%/81%, respectively). We concluded that our conventional system was able to identify most clinically significant staphylococcal species by means of relatively few tests with a high certainty and a high degree of reproducibility.
A collection of Enterobacter cloacae strains from Odense University Hospital from 1977 were compared with a collection from 1985 as regards acquired resistance traits. Among the strains with carbenicillin (Ca) resistance, the number of multiresistant strains decreased while the number with sole Ca-resistance increased. In 1977, a high proportion of the Ca-resistant (Ca-r) strains had plasmid-mediated beta-lactam resistance, but in 1985 the Ca-r strains were completely dominated by organisms with elevated amounts of chromosomally-mediated beta-lactamase. The latter, but not the former, strains were resistant to the newer cephalosporins (e.g. cefotaxime (Ctax)). The consumption of Ctax and cefuroxime increased from 0 kg in 1977 to 7.0 kg in 1985. It is therefore probable that this increase was the cause of the change in occurrence of the resistance types. Ninety-one % of the Ca-r strains were isolated from urinary samples in 1977. The percentage was only 31 in 1985. This change, concomitant with the increase in Ctax-r strains, can probably be explained by the better conditions for selection of Ctax-r mutants, producing greater amounts of chromosomal beta-lactamase, in wounds and respiratory tract than in urine.
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Thirty-six strains of yellow-pigmented Pseudomonas from clinical as well as non-clinical material and 11 reference strains of Pseudomonas were investigated by means of conventional bacteriological methods (a total of 53 different tests). Eighteen of the 36 yellow-pigmented strains could be classified as P. paucimobilis. Apart from the presence of lipid inclusions on beta-hydroxybutyrate, hydrolysis of DNA, and Tween 80 our results showed a high degree of accordance with other investigations. Eight strains showed characteristics compatible with inclusion in the CDC VE group; one orange-yellow strain showed the characteristics of P. vesicularis, and one was a pyoverdin negative, yellow P. putida. Eight strains remained unidentified. Strains of P. paucimobilis were most often resistant to antibiotics used for P. aeruginosa infections (viz. piperacillin, cefsulodin, ceftazidime) while the strains of the CDC VE group were often susceptible. Most strains were susceptible to the aminoglycosides. The difficulties in distinguishing yellow-pigmented strains of Pseudomonas from Flavobacterium spp. or Xanthomonas spp. are discussed.
Susceptibility to ciprofloxacin (Cfl) and nalidixic acid (Nal) was tested in vitro by means of the population analysis technique against six strains of Staphylococcus, one strain of Pseudomonas aeruginosa, and seven strains from five genera of Enterobacteriaceae. All strains of Staphylococcus were uniformly resistant to Nal as was the Pseudomonas aeruginosa strain, all bacteria being resistant to 250- less than 500 micrograms/ml. The Enterobacteriaceae were heterogeneous as regards susceptibility to Nal. With some strains minority populations of highly-resistant bacteria could be detected with frequencies of about 10(-6.3). The MIC for Cfl for the staphylococci varied between 0.25 and 0.50 microgram/ml. There were no differences in MIC of penicillinase-producing and penicillin-susceptible strains, either in Staphylococcus aureus or in Staphylococcus epidermidis. The MIC for Cfl in the enterobacteria varied between 0.004 and 0.03 microgram/ml. The MIC for Cfl in the Pseudomonas aeruginosa was 0.25 microgram/ml. MIC for Cfl increased in all strains when the parental strains were compared to bacteria selected from the plates with the highest concentration permitting growth, indicating heterogeneity against Cfl. But while the MIC of the selected enterobacteria were lower than one fourth of the level obtainable in serum, the MIC of the selected staphylococci and Pseudomonas aeruginosa were either exceeding the level obtainable in serum or were only a little lower than this level. While Cfl thus seems to be a promising antimicrobial agent in the treatment of infections caused by enterobacteria, the suitability for infections caused by staphylococci and Pseudomonas aeruginosa should be further explored.
Three commercial systems for the identification of non-enteric gram-negative rods were compared with conventional bacteriological methods as reference. The three systems were the API 20 NE, BIO-TEST ID-Trident, and ROSCO Diagnostic Tablets. The systems were tested on a set of 47 strains from the genus Pseudomonas, with the emphasis upon the yellow-pigmented species. The overall identification accuracy was 97% with the API, 19% with the BIOTEST and 68% with the ROSCO system. The API system was thus reliable, and it presented no major practical problems. The BIOTEST system was very handy. The main reason for the low accuracy was an error in the code book. The ONPG reaction was depicted as negative in the species P. paucimobilis. A positive ONPG test is a keymark in this species and 76% of the 20 strains of P. paucimobilis included in this investigation were also found positive with the BIOTEST system. The ROSCO tablets are convenient if the result of single reactions is desired. The time consumption per strain was 5.4, 4.4, and 6.2 min for the API, BIOTEST, and ROSCO systems respectively.
Enteric Group 69 has previously only been isolated from beef muscle. Two cases of isolations from human clinical specimens are reported on here: One from a throat swab and one from an abscess. In both cases, only EG 69 was cultured. This group has biochemical reactions similar to Enterobacter cloacae and Enterobacter sakazakii. EG 69 produces yellow pigment as E. sakazakii but only the former ferments sorbitol and dulcitol. EG 69 utilizes malonate and usually ferments sucrose slowly (3-4 days). EG 69 is distinguished from E. Cloacae by production of yellow pigment, fermentation of dulcitol and usually late fermentation of sucrose. EG 69 was found resistant to ampicillin and carbenicillin and susceptible to cephalothin. The pathogenic potential for man is still questionable, but EG 69 is shown to occur in human clinical specimens.
Population analyses of susceptibility to cefotaxime (CTX) and desacetyl-cefotaxime (DCTX) of strains of Staphylococcus and some genera of Enterobacteriaceae were carried out. DCTX, which is the main metabolite of CTX, has antimicrobial activity. The penicillinase-producing strains of S. aureus and S. epidermidis were homogeneous as regards susceptibility to both agents. CTX was about 4-8 times more active than DCTX. The methicillin-resistant strains contained a sub-population of resistant bacteria with both CTX and DCTX. The frequency of resistant bacteria was 10(-6) - 10(-5). The E. coli strain was homogeneous to both agents. The strains of Enterobacter cloacae and Citrobacter freundii had a sub-population of resistant bacteria with both agents. The frequency of resistant bacteria was 10(-7) - 10(-4.5). In Klebsiella pneumoniae no resistant sub-population was found. CTX was about four times more active than DCTX with the strains of the Enterobacteriaceae. DCTX had no advantage over CTX as regards homogeneity of susceptibility of the populations examined. CTX seems applicable for treatment of infections with E. coli, Klebsiella pneumoniae, and penicillinase-producing, methicillin-susceptible Staphylococcus, but should not be used alone in treatments of infections with Enterobacter cloacae or Citrobacter freundii.
Population analysis of susceptibility to cefotaxime (CTX) in eight species of Enterobacteriaceae was carried out. One strain of each species was examined. The strains represented their individual species as regards natural susceptibility to ampicillin (A) and carbenicillin (Ca). Cephalothinase activity of the parental strains and strains selected on the plates with the highest concentration that allowed growth was determined by an ultraviolet assay. The populations of the A-susceptible/Ca-susceptible (A-s/Ca-s) species, Escherichia coli and Proteus mirabilis were homogeneous as regards susceptibility to CTX. The A-resistant/Ca-resistant (A-r/Ca-r) species, Klebsiella oxytoca and Citrobacter koseri, were less homogeneous, but in all four mentioned species no increase in cephalothinase activity was observed between the parental strains and the strains selected in the population analysis. The four A-r/Ca-s species, Enterobacter cloacae, Citrobacter freundii, Proteus vulgaris, and Morganella morganii, were heterogeneous. The frequency of CTX-r mutants was approx. 10(-6.5). The IC50 for CTX was 2(7.5)-2(8.5) times higher for the mutants than for the parental strains. The CTX resistance was maintained in subcultures of the strains. All four species had a very high increase in cephalothinase activity from parental strains to the strains selected in the population analysis. Only the enzyme of Proteus vulgaris was able to hydrolyze CTX.