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PubMedDate not supplied

[Enterobacter aerogenes pneumopathy treated by a cefepime-sulbactam-gentamicin combination].

BACKGROUND: Enterobacter aerogenes is the fifth most frequent pathogen causing nosocomial infections. Several strains have developed multiple resistance by over-production of a natural cephalosporinase and by the presence of wide-spectrum betalactamases. CASE REPORT: A patient with chronic respiratory failure developed Enterobacter aerogenes pneumonia while under mechanical ventilation. The infection was successfully treated with a cefepime, sulbactam, gentamycin combination. DISCUSSION: Choosing the optimum antibiotic therapy is a difficult task in many nosocomial infections. In certain cases, combining a betalactamase inhibitor with the appropriate antibiotic can improve bactericidal activity and provide successful cure.

Anti-Bacterial Agents↗
PubMed1998

[Enterobacter amnigenus. An unusual human pathogen].

BACKGROUND: Enterobacter amnigenus is a bacteria with doubtful pathogenicity. The observation of a patient with a well-documented E. amnigenus infection has prompted us to review the pathology caused by this microorganism. METHODS: Retrospective evaluation of the clinical charts of patients with any isolate positive for E. amnigenus over a period of 46 months. Based on the clinical data, presence or absence of other causal microorganisms and/or alternative diagnosis, E. amnigenus was classified as definitive, probable, or improbable cause of infection. RESULTS: We analyzed 15 E. amnigenus isolates, representing 0.97 of 10,000, the total bacterial isolates in our laboratory for this period, and 0.52% of those corresponding to Enterobacter sp. We were able to clinically evaluate E. amnigenus in 7 patients, in whom infection by this microorganism was classified as definitive in 4, probable in 1, and improbable in 2. Antibiotic susceptibility studies showed a resistance level of 83% to ampicillin, 75% to cefazoline and cefoxitine, and 33% to amoxicillin-clavulanic acid. All isolates were susceptible to third-generation cephalosporins, aztreonam, ciprofloxacin, cotrimoxazole and aminoglycosides. CONCLUSIONS: E. amnigenus cause well-documented bacterial infection in man. Thus, isolation of this microorganism should not be considered as a contaminant or simple colonizer. The clinical behavior and antimicrobial susceptibility of E. amnigenus is similar to that of E. cloacae, a taxonomically-related species.

Aged↗
PubMedDate not supplied

[Comparative immunological study of glyceraldehydephosphate dehydrogenase in Enterobacteriaceae: contribution of an anti-glyceraldehydephosphate dehydrogenase antiserum of Enterobacter intermedium].

A comparative immunological study of glyceraldehyde-3-phosphate dehydrogenase among Enterobacteriaceae was carried out with an antiserum against Enterobacter intermedium G-3-PDH. Results of immunodiffusion experiments and microcomplement fixation studies showed E. intermedium to be a homogeneous species. The genera Enterobacter and Escherichia were found to be quite heterogeneous.

Complement Fixation Tests↗
PubMed2006

Characterization of a collection of Enterobacter sakazakii isolates from environmental and food sources.

Enterobacter sakazakii has emerged as a rare cause of neonatal meningitis, septicemia and enterocolitis. Contaminated infant milk formula (IMF) has been identified as one infection route. A small number of clinical outbreaks have been epidemiologically linked to IMF contaminated post-pasteurization during manufacture and/or mishandled when reconstituted. Currently no agreed standardized typing protocol has been developed to trace E. sakazakii. The objectives of this study were to apply biochemical and genetic methods to characterize 51 environmental and food E. sakazakii isolates and 6 E. sakazakii type strains. Isolates were presumptively identified using biochemical profiles based on API 20E and ID32E methods and by culture on differential selective Druggan Forsythe Iversen (DFI) agar. Identification was subsequently confirmed by real time polymerase chain reaction (PCR). All but one of the isolates was identified as E. sakazakii by biochemical profiling. One isolate was identified as Escherichia vulneris by ID 32E and as Pantoea agglomerans by API 20E. All isolates produced green/blue colonies on DFI medium characteristic of this organism. Real time PCR could differentiate between E. sakazakii, Enterobacter spp. and other Enterobacteriacae. Analysis of RAPD banding patterns revealed 3 major clusters of E. sakazakii. There was a large degree of diversity noted amongst the remaining isolates. Our findings indicate that RAPD may be applied as a useful and reliable tool for direct comparison of E. sakazakii isolates providing traceability through the infant formula food chain.

Cluster Analysis↗
PubMed2005

Survival and growth of Enterobacter sakazakii in infant rice cereal reconstituted with water, milk, liquid infant formula, or apple juice.

AIMS: To determine survival and growth characteristics of Enterobacter sakazakii in infant rice cereal as affected by type of liquid used for reconstitution and storage temperature after reconstitution. METHODS AND RESULTS: A commercially manufactured dry infant rice cereal was reconstituted with water, apple juice, milk, or liquid infant formula, inoculated with a 10-strain mixture of E. sakazakii at populations of 0.27, 0.93, and 9.3 CFU ml(-1), and incubated at 4, 12, 21 or 30 degrees C for up to 72 h. Growth did not occur in cereal reconstituted with apple juice, regardless of storage temperature, or in cereal reconstituted with water, milk, or formula and stored at 4 degrees C. The lag time for growth in cereal reconstituted with water, milk, or formula was decreased as the incubation temperature (12, 21 and 30 degrees C) was increased. Upon reaching maximum populations of 7-8 log10 CFU ml(-1), in some instances populations decreased to nondetectable levels during subsequent storage which was concurrent with decreases in pH. CONCLUSIONS: Enterobacter sakazakii initially at very low populations can rapidly grow in infant rice cereal reconstituted with water, milk, or infant formula. SIGNIFICANCE AND IMPACT OF THE STUDY: Reconstituted infant rice cereal can support luxuriant growth of E. sakazakii. Reconstituted cereal that is not immediately consumed should be discarded or stored at a temperature at which E. sakazakii and other food-borne pathogens cannot grow.

Animals↗
PubMed1999

Emergence of Enterobacter aerogenes as a major antibiotic-resistant nosocomial pathogen in Belgian hospitals.

OBJECTIVE: To study the epidemiology of Enterobacter aerogenes infections in Belgian hospitals and determine whether recent trends show an increase in incidence of E. aerogenes infections and antimicrobial resistance. METHODS: Data from the bloodstream infection component of the National Surveillance of Hospital Infections (October 1992 to September 1996 data in 45 hospitals) and from a retrospective study on E. aerogenes clinical isolates (1994 and 1995 data in 41 hospitals) were analyzed. RESULTS: E. aerogenes was recovered from clinical specimens with a mean incidence of 4.6 isolates per 10 000 patient-days and caused 0.20 bloodstream infections per 10 000 patient-days during the surveyed periods, respectively. Both rates increased significantly throughout the years. The proportion of E aerogenes within the Enterobacter genus was 35.4% in clinical isolates and 41.2% in bloodstream infections. Both proportions significantly increased over time. Incidence was not statistically different by hospital size but showed major differences between geographic regions. Resistance rates to third-generation cephalosporins and fluoroquinolones increased, and imipenem resistance emerged in several hospitals. CONCLUSIONS: This report provides evidence of an increase in E. aerogenes infections in Belgian hospitals and documents an increase in antimicrobial resistance of E. aerogenes strains. These figures provide a baseline for further surveillance data.

Journal Article↗
PubMed1999

In vitro selective concentrations of cefepime and ceftazidime for AmpC beta-lactamase hyperproducer Enterobacter cloacae variants.

This study aimed to compare the selective concentrations of cefepime and ceftazidime on Enterobacter cloacae. A mixed culture of a wild-type ceftazidime/cefepime-susceptible (4x107 CFU/mL) strain and an ampC derepressed Enterobacter cloacae (105 CFU/mL) strain (relative proportions 99.75% and 0.25%) was challenged for 4 h with different antibiotic concentrations of ceftazidime and cefepime (0.03--4096 mg/L), and then transferred to drug-free medium. The proportion of wild-type versus derepressed population was evaluated after 24 h. Ceftazidime and cefepime selected the derepressed variant at concentrations ranging from 1 to 4096 and from 0.12 to 16 mg/L respectively. These results suggest that serum concentrations attainable with a 2 g/8 h cefepime dosage may be able to suppress the emergence of derepressed ampC mutants.

Journal Article↗
PubMed1983

Nitrogenase activity (acetylene reduction) of root-associated, cold-climate azospirillum, enterobacter, Klebsiella, and pseudomonas species during growth on various carbon sources and at various partial pressures of oxygen.

A comprehensive view of the diazotrophic bacterial flora of plants requires that attention be paid to the appropriate carbon and oxygen requirements during isolation of the bacteria. Twenty compounds (monosaccharides, disaccharides, polyols, and organic acids) were therefore examined as carbon and energy sources for nitrogenase activity in semisolid stab cultures at pO(2) values of 0.21, 0.02, and </=0.002 with 12 strains of diazotrophic root-associated bacteria. With the facultatively anaerobic bacteria of the genera Klebsiella and Enterobacter, the best substrate was sucrose, followed by fructose and mannitol, whereas among the organic acids, only malic and fumaric acids supported any activity. With the obligately aerobic bacteria of the genera Azospirillum and Pseudomonas, disaccharides were not utilized for nitrogen fixation, but several organic acids were accepted in addition to monosaccharides and polyols; malate and glucose were the best substrates. The patterns of the carbon sources utilized for nitrogen fixation were coherent within the species, with the exception of one Klebsiella pneumoniae and one Enterobacter agglomerans strain, both isolated from the same individual grass plant, which were unable to utilize lactose. Anaerobic conditions (pO(2) value of </=0.002) were required for maximum nitrogenase activity with the facultatively anaerobic bacteria, with the exception of one strain of E. agglomerans, which required atmospheric oxygen (pO(2) value of 0.21). Also, the obligately aerobic diazotrophs required atmospheric oxygen for maximum nitrogenase activity. The maximum specific nitrogenase activities (expressed as micromoles of C(2)H(4) . milligram of bacterial protein . hour) noted during the exponential growth phase of the bacteria were the following: 2.68 with Azospirillum lipoferum on malate, 2.41 with K. pneumoniae and 1.58 with E. agglomerans on sucrose, and 0.95 with Pseudomonas sp. on malate.

Journal Article↗
PubMed1995

Chitinolytic Enterobacter agglomerans Antagonistic to Fungal Plant Pathogens.

Three Enterobacter agglomerans strains which produce and excrete proteins with chitinolytic activity were found while screening soil-borne bacteria antagonistic to fungal plant pathogens. The chitinolytic activity was induced when the strains were grown in the presence of colloidal chitin as the sole carbon source. It was quantitated by using assays with chromogenic p-nitrophenyl analogs of disaccharide, trisaccharide, and tetrasaccharide derivatives of N-acetylglucosamine. A set of three fluorescent substrates with a 4-methylumbelliferyl group linked by (beta)-1,4 linkage to N-acetylglucosamine mono- or oligosaccharides were used to identify the chitinolytic activities of proteins which had been renatured following their separation by electrophoresis. This study provides the most complete evidence for the presence of a complex of chitinolytic enzymes in Enterobacter strains. Four enzymes were detected: two N-acetyl-(beta)-d-glucosaminidases of 89 and 67 kDa, an endochitinase with an apparent molecular mass of 59 kDa, and a chitobiosidase of 50 kDa. The biocontrol ability of the chitinolytic strains was demonstrated under greenhouse conditions. The bacteria decreased the incidence of disease caused by Rhizoctonia solani in cotton by 64 to 86%. Two Tn5 mutants of one of the isolates, which were deficient in chitinolytic activity, were unable to protect plants against the disease.

Journal Article↗
PubMed2005

Performance of media for recovering stressed cells of Enterobacter sakazakii as determined using spiral plating and ecometric techniques.

A study was done to determine the performance of differential, selective media for supporting resuscitation and colony development by stressed cells of Enterobacter sakazakii. Cells of four strains of E. sakazakii isolated from powdered infant formula were exposed to five stress conditions: heat (55 degrees C for 5 min), freezing (-20 degrees C for 24 h, thawed, frozen again at -20 degrees C for 2 h, thawed), acidic pH (3.54), alkaline pH (11.25), and desiccation in powdered infant formula (water activity, 0.25; 21 degrees C for 31 days). Control and stressed cells were spiral plated on tryptic soy agar supplemented with 0.1% pyruvate (TSAP, a nonselective control medium); Leuschner, Baird, Donald, and Cox (LBDC) agar (a differential, nonselective medium); Oh and Kang agar (OK); fecal coliform agar (FCA); Druggan-Forsythe-Iversen (DFI) medium; violet red bile glucose (VRBG) agar; and Enterobacteriaceae enrichment (EE) agar. With the exception of desiccation-stressed cells, suspensions of stressed cells were also plated on these media and on R&F Enterobacter sakazakii chromogenic plating (RF) medium using the ecometric technique. The order of performance of media for recovering control and heat-, freeze-, acid-, and alkaline-stressed cells by spiral plating was TSAP > LBDC > FCA > OK, VRBG > DFI > EE; the general order for recovering desiccated cells was TSAP, LBDC, FCA, OK > DFI, VRBG, EE. Using the ecometric technique, the general order of growth indices of stressed cells was TSAP, LBDC > FCA > RF, VRBG, OK > DFI, EE. The results indicate that differential, selective media vary greatly in their abilities to support resuscitation and colony formation by stressed cells of E. sakazakii. The orders of performance of media for recovering stressed cells were similar using spiral plating and ecometric techniques, but results from spiral plating should be considered more conclusive.

Bacteriological Techniques↗
PubMed1970

Differentiation of Serratia from Enterobacter on the basis of nucleoside phosphotransferase production.

Precoated cellulose thin-layer chromatograms were used to detect the production of guanosine 5'-phosphate from guanosine and p-nitrophenylphosphate by whole-cell preparations. One-hundred per cent of Serratia (163 strains) and 84% of E. liquefaciens (15 of 18 strains) produced the nucleotide. All other Enterobacter (23 strains), Klebsiella (10 strains), and E. coli (10 strains) were negative for the production of this nucleotide. The entire test procedure could be carried out in 4 hr. It is proposed that E. liquefaciens is more closely related to Serratia than Enterobacter and that reclassification of these organisms should be investigated.

Chromatography, Thin Layer↗
PubMed1993

Clinical and bacteriological study of nosocomial infections due to Enterobacter aerogenes resistant to imipenem.

Enterobacter aerogenes strains resistant to imipenem were isolated in 10 patients, 7 of whom had received imipenem-cilastatin. The strains were differentiated by biotype, antibiotype, and plasmid content. All of the strains overproduced a chromosomal cephalosporinase and lost a major outer membrane protein with a size of about 40 kDa. In 5 of the 10 patients, E. aerogenes strains resistant to extended-spectrum cephalosporin were isolated during the same stay. In three patients, the similarity between the imipenem-susceptible and -resistant strains suggests the occurrence of mutation and reversion in vivo. The combination imipenem-cilastatin has been critically important for use with multiresistant strains of Enterobacter spp., but its use increases the risk of selection of imipenem-resistant strains.

Bacterial Outer Membrane Proteins↗
PubMed2006

Comparison of two chromogenic media and evaluation of two molecular based identification systems for Enterobacter sakazakii detection.

BACKGROUND: Enterobacter sakazakii is a foodborne pathogen that has been associated with sporadic cases and outbreaks causing meningitis, necrotizing enterocolitis and sepsis especially in neonates. The current FDA detection method includes two enrichment steps, the subculturing of the second enrichment broth on a selective agar (VRBG), a further subculturing of selected grown colonies on TSA and the subsequent biochemical identification of yellow-pigmented colonies by API20E. However, there is a strong need for simplified methods for isolation and identification of E. sakazakii. In this study, two chromogenic media, which allow to indicate presumptive E. sakazakii colonies by the alpha glucosidase activity, as well as a newly developed 1,6-alpha-glucosidase based conventional PCR assay and a rRNA oligonucleotide probe based commercial test system for identification of presumptive E. sakazakii were evaluated on 98 target and non-target strains. The methods were compared with respect to specificity aspects. RESULTS: A total of 75 presumptive E. sakazakii and 23 non-target strains were analysed by using chromogenic media, alpha-glucosidase based PCR assay, and the VIT assay. For most presumptive E. sakazakii strains on the chromogenic media, the PCR and VIT assay confirmed the identification. However, for a number of presumptive E. sakazakii isolates from fruit powder, the alpha-glucosidase PCR and VIT assay did not correspond to the typical E. sakazakii colonies on DFI and ESIA. Further characterization by API32E identification, phylogenetic analysis of partial 16S rRNA sequences and ribotyping strongly suggested, that these strains did not belong to the species E. sakazakii. The newly developed alpha-glucosidase based PCR assay as well as the commercially available VIT Enterobacter sakazakii identification test showed an excellent correlation with the 16S rRNA data, and are thus well suited for identification of E. sakazakii. CONCLUSION: The results indicate that presumptive colonies on ESIA and DFI media need further species identification. Both evaluated molecular methods, the alpha-glucosidase PCR and the 16S RNA in situ hybridisation test (VIT), although based on completely different target regions and methodologies performed equally well in terms of specificity.

Base Sequence↗
PubMed2004

A new protocol for the detection of Enterobacter sakazakii applied to environmental samples.

Enterobacter sakazakii is a motile, peritrichous, gram-negative rod that was previously known as a yellow pigmented Enterobacter cloacae. It is documented as a rare cause of outbreaks and sporadic cases of life-threatening neonatal meningitis, necrotizing enterocolitis, and sepsis. E. sakazakii has been isolated from milk powder-based formulas, and there is thus a need to investigate whether and where E. sakazakii occurs in these manufacturing environments. For this purpose, a simple detection method was developed based on two features of E. sakazakii: its yellow pigmented colonies when grown on tryptone soy agar and its constitutive alpha-glucosidase, which is detected in a 4-h colorimetric assay. Using this screening method, E. sakazakii strains were isolated from three individual factories from 18 of 152 environmental samples, such as scrapings from dust, vacuum cleaner bags, and spilled product near equipment. The method is useful for routine screening of environmental samples for the presence of E. sakazakii.

Colorimetry↗
PubMed2006

Isolation of Enterobacter sakazakii from stable flies, Stomoxys calcitrans L. (Diptera: Muscidae).

Enterobacter sakazakii is an opportunistic foodborne pathogen that causes meningitis, enterocolitis, and sepsis, primarily in immunocompromised infants. Previously, it was suggested that stable flies, Stomoxys calcitrans, were a vector or reservoir of this pathogen. In our study, by means of a culturing approach combined with 16S rDNA PCR-restriction fragment length polymorphism genotyping and sequencing, we screened 928 individual stable flies collected in Kansas and Florida. Two stable flies (0.2%) were positive for E. sakazakii. In addition, 411 (44%) stable flies carried bacteria-forming red colonies (presumably enterics) on a violet red bile glucose agar (mean count = 6.4 x 10(4) CFU per fly), and 120 (13%) stable flies carried fecal coliforms (mean count = 8.7 X 10(3) CFU per fly). Sequencing of 16S rDNA showed that enterics from violet red bile glucose agar were represented by several genera, including Escherichia, Shigella, Providencia, Enterobacter, Pantoea, Proteus, Serratia, and Morganella. Our study shows that stable flies carry bacteria typically present in animal manure (a developmental site of stable fly larvae), which indicates that the natural reservoir of E. sakazakii is the digestive tract or manure of domestic animals. The low prevalence of E. sakazakii associated with stable flies suggests that stable flies do not play a major role as a reservoir or vector of this pathogen.

Animals↗
PubMed1981

Neonatal enterobacter suppurative arthritis and osteomyelitis.

Suppurative arthritis of the right knee and osteomyelitis of the adjacent femur complicated a urinary tract infection in an 18-day-old infant with a posterior urethral valve causing urinary flow obstruction. Initially cephalosporine sensitive Enterobacter caused the urinary tract infection. Shortly following cephazolin therapy, cephalosporine resistant Enterobacter microorganisms were isolated both from the urine and the knee joint fluid. These two infections were successfully treated with a combination of gentamicin and Co-trimoxazole. Gram-negative bacteria should be considered among the pathogens in neonatal osteoarticular infections, particularly if a urinary tract infection co-exists.

Arthritis, Infectious↗
PubMed1975

[Salmonella typhimurium masked as an Enterobacter species (author's transl)].

A bacterial strain at first sight appearing to be an Enterobacter species causing enteritis could be identified as Salmonella typhimurium showing only a low formation of H2S. This small degree of H2S formation could not be demonstrated on commercial media ready for use. The high antibiotics resistance of the strain in question points to the possibility of its having undergone several antibiotics passages without recognition. Thus, serological verification is recommended in the case of so-called Enterobacter species appearing as agents of enteritis.

Enteritis↗
PubMedDate not supplied

Enterobacter hafnaie infection: report of two cases and review of the literature.

Two of 255 wounded soldiers developed nosocomial infection with Enterobacter hafniae. This species is rarely associated with urinary or gastrointestinal disease, and had not been heretofore reported in the setting of localized or bacteremic wound infection. Difficulties in nomenclature and identification have obviated accurate assessment of the importance of E. hafniae as a pathogen. Nevertheless, in view of the relative sensitivity of this species to antibiotics one should be careful to distinguish E. hafniae from other members of the genus Enterobacter.

Adult↗