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PubMed1986

Properties of free and bound Citrobacter freundii lipopolysaccharides.

Culture medium content of free lipopolysaccharide (LPS) components spontaneously released from a Citrobacter freundii culture grown in minimum synthetic medium was determined during early (8-hr culture) and late (24-hr culture) phases of growth. As judged by Limulus-lysate test, free LPS occurred in the medium as early as after 8 hrs of incubation, i.e. at the beginning of log growth phase. As the culture continued to grow the LPS amount released into culture medium kept rising, reaching 30% of endotoxin present in 24-hr Citrobacter culture. The released LPS complex was isolated by separation and its physicochemical, immunochemical and biological properties were determined and compared with those of cell-bound endotoxin recovered from cells by phenol extraction. Comparisons revealed distinct differences in the chemical composition and the degree of heterogeneity; free LPS was less heterogeneous. Immunologically, free LPS differed from bound LPS in the structure of macromolecules, but was identical with it in some antigenic determinants. The biological activity of free LPS preparation was greater than that of cell-bound LPS.

Animals↗
PubMed1989

[The characteristics of amino acid catabolism in bacteria of the genus Citrobacter].

The comparison of the occurrence of enzymes effecting the deamination of dicarbon, aromatic and oxyamino acids, as well as transamination enzymes, in Citrobacter bacteria and the activity levels of these enzymes was made. The constant sign of such bacteria was the presence of serine and threonine dehydratase activity. 92% of the strains showed the presence of phenylalanine deaminase. No tryptophan activity was established. 96-98% of Citrobacter strains possessed phenylalanine, tyrosine and tryptophan aminotransferases with alpha-ketoglutaric acid functioning as the acceptor of the amino group.

Amino Acids↗
PubMed1989

[Microbial contamination of water by pipe and tube materials. 3. Behavior of E. coli, Citrobacter freundii and Klebsiella pneumoniae].

Materials water comes into contact with can promote the microbial growth as it could be shown before. The reaction of an unspecific microorganism flora and of Legionella pneumophila in pipes and hoses has been described in the two previous communications. The investigation with L. pneumophila has shown that even a pathogen organism can grow upon the materials. Therefore it was of special interest to prove whether indicator organisms for the testing of drinking water can grow in pipes and hoses as well. Escherichia coli, Citrobacter freundii and Klebsiella pneumoniae grew after the experimental contamination for many weeks on the rubber hose until the test was finally stopped, in the other pipes and hoses (glass, high-grade steel, PVC, PE, PA, PTFE and silicone) E. coli could be found for maximal 7 weeks, Citrobacter freundii for 1 week and Klebsiella pneumoniae for maximal 3 weeks. In the copper pipe the organisms could be found only for a few days.

Citrobacter↗
PubMed1989

The biochemical differentiation between Salmonella and Citrobacter.

A number of bacterial isolates which could not be identified as either Salmonella or Citrobacter by conventional biochemical tests and could not be typed as Salmonella with available antisera, were further examined biochemically and by lysis with phage Felix 0.1. Glycerol-positive salmonellae and lysine-positive citrobacters were encountered, which could be confused with the other genus, but when the reactions of such strains were examined in the other tests, accurate identifications could be done. Of the tests examined, glycerol fermentation, the beta-galactosidase test, lysine decarboxylation, sorbose fermentation, galacturonate fermentation and lysis by the phage could be used in the differentiation. These tests in combination, rather than 1 or 2 single tests gave reliable and conclusive differentiation.

Animals↗
PubMedDate not supplied

[Dependence of the dynamics of the multiplication of bacteria in the genus Citrobacter on the temperature factor and on the product type in experimental contamination].

A study was made of the time course of the reproduction of bacteria of the Citrobacter genus in milk, sausage meat and vermicelli during experimental contamination, with incubation of cultures at 3 temperature regimens (24, 37 and 44 degrees C). Estimation of the results of experiments was performed by counting the number of the colonies on the surface of 2% beef-extract agar. It was established that within the first 6 h, at 24 and 37 degrees C there was an identical growth of the number of microorganisms in all the foods under study. During incubation at 44 degrees C (for 4-8 h), there was a slower reproduction of bacteria in milk as compared with sausage meat. It was revealed that food consistency had an effect on the intensity of the reproduction of bacteria of the Citrobacter genus depending on the time of incubation and temperature.

Animals↗
PubMed1984

[Enterotoxigenicity and neuraminidase activity of bacteria of the genus Citrobacter].

The data obtained in the study of Citrobacter strains isolated from patients with diarrheal diseases and from healthy persons are presented: enterotoxigenicity was studied in 68 strains, while neuraminidase activity in 41 strains. Among the strains of these groups 9 strains with active enterotoxin and 2 strains producing active neuraminidase were detected. The criteria for subdividing Citrobacter strains according to the activity of their thermolabile enterotoxin are proposed.

Animals↗
PubMed1981

The murein of citrobacter O-serogroup Ci23 Vi+.

The isolation and analysis of the Citrobacter O-serogroup Ci23Vi+ murein are described. The murein consists of alanine, glutamic acid, diaminopimelic acid (occurring in the molar ratio 1.5 : 1: 0.9), N-acetylmuramic acid and N-acetylglucosamine. Dialysable products resulting from the digestion of the Citrobacter O-serogroup Ci23Vi+ murein with egg white lysozyme resemble closely those obtained from the E. coli B murein.

Chemical Phenomena↗
PubMed1981

[Antigenic relations between enteropathogenic Escherichia O151:K, Citrobacter and Hafnia].

The strains isolated from acute dysentery patients and convalescents and identified as E. coli O151:K--were studied. Diagnostic errors due to inexact genus determination were revealed, and the isolated strains were found to belong to Citrobacter and Hafnia. The main biochemical differences allowing to differentiate E. coli O151:K--from these two genera were established. The study also showed the necessity of some tests, such as the tests for citrate assimilation in Simmons' medium and sodium malonate assimilation, the determination of indole production, the determination of differences in the methyl red and Voges--Proskauer reactions at different temperatures. The poor unilateral antigenic relationship of the strains under study, agglutinating with antiserum to E. coli O151, Citrobacter O1 and O14 and Hafnia C18 was revealed.

Agglutination Tests↗
PubMed1982

[Compared studies of antimicrobial agents against E. coli, Klebsiella, Citrobacter and Proteus isolated from urinary tract infections].

In vitro activities of antibacterial agents against E. coli, Klebsiella, Citrobacter and Proteus which were isolated from patients urinary tract infections at 8 hospitals in Japan, were investigated by agar dilution method from July to October in 1979. The summarized results are as follows. 1. Among oral antibacterial agents, MPC and PPA have showed potent antibacterial activities against E. coli and Klebsiella. Among parenteral antibiotics, CTM was the most active against E. coli and Klebsiella. However, ABPC-resistant E. coli and Klebsiella have appeared to occupy about 40% and 96% of bacteria isolated from urinary tract infections, respectively. 2. In vitro activities of antibacterial agents against Proteus and Citrobacter showed not so potent. 3. Causative organisms in female patients with simple urinary tract infections were mainly E. coli and Klebsiella. 4. Among oral antibacterial agents, PPA have shown similar antimicrobial activities against E. coli isolated from simple and complicated urinary tract infections. ABPC and MPC have been influenced in some degree by these factors. However, parenteral antibiotics are not influenced by these factors. On the other hand, in vitro activities of antibacterial agents against Klebsiella isolated from simple and complicated urinary tract infections were similar.

Adult↗
PubMed1980

Gram-negative sepsis in neonates: a nursery outbreak due to hand carriage of Citrobacter diversus.

An outbreak of Citrobacter diversus infections occurred in a newborn nursery at a 350-bed community hospital during September and October 1978. Two infants developed sepsis and meningitis and nine additional infants had asymptomatic umbilical colonization. These infants did not differ from control, noncolonized infants with respect to numerous clinical and environmental variables. Surveillance cultures failed to implicate an environmental source for the Citrobacter. However, cultures of nursery personnel identified a hand-carrier whose removal eliminated neonatal colonization with C diversus and decreased the number of isolates of certain other enteric bacteria found on umbilical stumps. Factors implicated in the perpetuation of the carrier state in this nurse included marked dermatitis from repeated hand washing and hand care practices involving the overnight use of plastic gloves and nutritive hand cream. The mode of transmission within the nursery appeared to be from nurse's hands to infant's umbilicus. Use of triple dye on umbilical stumps and chlorhexidine hand washing preparations did not eliminate this cycle. Surgical manipulation of colonized umbilical stumps may have been responsible for illness in two infants.

Carrier State↗
PubMed1975

[New serological investigations into O-antigenic relations between Escherichia coli, Salmonella, Arizona and Citrobacter (author's transl)].

During a systemic investigation into O-antigenic relations within the family Enterobacteriaceae, with special emphasis on serological relationships between O-antigens (or O-groups) of E. coli and various O-groupps of Salmonella, Arizona, and Citrobacter, our tests confirmed some findings previously descried by other authors, some were not confirmed, and other antigenic relationships were discovered which have not yet been published. Individually tested were O-Antigens of 142 serologically defined E. coli types by using O-factorsera of Salmonella, Arizona, and Citrobacter for the slide agglutination. The slide agglutination was applied in preference to the tube-agglutination, not only because the former has been generally adopted but it also shows broader reactions...

Agglutination Tests↗
PubMedDate not supplied

[The pathogenicity factors in different representatives of the genus Citrobacter].

No trustworthy distinctions were revealed under the comparative analysis of properties of bacteria of Citrobacter genus from 3 studied ecological groups (from patients with diarrhea, from healthy persons and patients with extraenteric pathological process). It allows the finding of potentially partogenic bacteria of Citrobacter genus in patients with diarrhea to be considered the manifestation of dysbacteriosis.

Anti-Bacterial Agents↗
PubMed1996

[Variation in transfer resistance to cefotaxime, ceftazidime and aztreonam in strains of Acinetobacter sp., Enterobacter sp. and Citrobacter sp. isolated from the same university hospitals].

BACKGROUND: In the last decade were in SR documented new problems in resistance to the newer antibiotics that with regard to their structure and antibacterial properties resisted to the known mechanism of bacterial resistance. The emergence of multiple drug resistance to the new betalactams is connected both with frequent application of these drugs in the hospitals and transfer of R plasmids. METHODS AND RESULTS: We studied composition and transferability of resistance to newer betalactam antibiotics in strains of Acinetobacter sp., Enterobacter sp, and Citrobacter sp. isolated during one month in patients from two teaching University Hospitals. All strains studied were resistant to cefotaxime (CTX), ceftazidime (CAZ) and aztreonam (ATM) but Acinetobacter strains, although resistant also to CAZ and ATM transferred the resistance to CTX only. Thus, resistance to CAZ and ATM has a chromosomal origin in these strains. A strain of Citrobacter sp., resistant to CTX, CAZ and ATM, produced a ESBL betalactamase detectable in a double-disk diffusion method (Fig. 1). An Enterobacter cloacae strain transfers directly the resistance to all new betalactams indicated. Their hydrolysis by these strains points to their production of new types of extended-spectrum beta-lactamases ESBL). CONCLUSIONS: We strongly recommend to be strictly rational in the use of new betalactams of CTX, CZA or ATM type because it is suspected that, especially in so-called empirical prophylaxis or treatment, they exert a strong selective pressure toward the prevalence of mutants with transferable ESBL-producing nosocomial bacteria resistant to these drugs.

Acinetobacter↗
PubMed1977

[Sensitivity to antibiotics of bacteria of the genus Citrobacter isolated from patients with acute intestinal infections of unclear etiology].

Sensitivity of Citrobacter isolated from the patients with acute gastro-intestinal infections of unknown etiology in Volgograd was studied. The antibiotic sensitivity to antibiotics was determined by the method of dilution in nutrient agar. Most of the isolates were sensitive to kanamycin, tetracycline and polymyxin. All strains were resistant to ristomycin. The sensitivity of the local strains differed from that described in the literature. Among sero groups 05, 08 and 023 all strains were resistant to oleandomycin, lincomycin and ristomycin. Polyresistant strains of Citrobacter were registered in Volgograd. The greater part (79 per cent) of the strains were simultaneously resistant to 4-6 antibiotics.

Acute Disease↗
PubMed1976

[Biochemical characteristics of strains from the Citrobacter and Hafnia genera and their laboratory identification].

A study of biochemical properties of 176 strains of coprocultures isolated from the patients and persons who sustained various acute enteric diseases, and also from contacts and persons examined for prophylaxis showed that they corresponded to the taxonomic definition of the Citrobacter and Hafnia genus. In connection with the similarity by biochemical properties between bacteria of Citrobacter and Salmonella genus and bacteria of Hafnia and Shigella genus it is of expedience in their identification and differentiation carried out in bacteriological laboratories in the diagnosis of enteric infections to use several biochemical tests.

Acute Disease↗
PubMed1966

Beta-galactosidase for distinguishing between Citrobacter and Salmonella.

Detection of beta-galactosidase with the aid of o-nitrophenyl-beta-d-galactopyranoside (ONPG) was examined as a means for distinguishing between Citrobacter and Salmonella. Several factors which influence sensitivity and reliability of the test were studied. A bacteriostat, sodium azide, was included to permit prolonged incubation of weak and negative strains of enteric bacilli. By the procedure described, salmonellae gave negative ONPG tests; all of 171 strains of Citrobacter gave positive tests.

Azides↗
PubMed1984

Endocarditis due to Citrobacter freundii.

The etiologic association of acute bacterial endocarditis with the Citrobacter species has been rare, although it is one of the opportunistic organisms that afflicts the elderly, neonates, the debilitated and immunocompromised. We report a case of endocarditis due to Citrobacter freundii.

Journal Article↗
PubMed1991

Review of Citrobacter bacteremia in cancer patients over a sixteen-year period.

A review was conducted of 65 episodes of Citrobacter bacteremia in cancer patients during a 16-year period. Cases of polymicrobial bacteremia were excluded from this analysis. The infection occurred most commonly in patients with acute leukemia. Most patients acquired the infection in the hospital, and 57% had received antibiotic therapy during the preceding ten days. Fever occurred in 98% of cases and shock in 17%. Thirty-eight percent of patients had concomitant pneumonia. Patients with shock, pneumonia or hemorrhage had a substantially poorer prognosis. The response rate was 72% for patients who received appropriate antibiotics. Patients who continued to have positive blood culture results while receiving appropriate antibiotic therapy had a poor prognosis. Beta-lactam antibiotics were more effective than aminoglycosides.

Adolescent↗