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At least 397 records · Page 22Linked to original sources
PubMed1990

Use of urea filter paper disc to detect urease activity in Enterobacteriaceae by multipoint replication techniques.

A new method of detecting urease activity in Enterobacteriaceae was developed. An 8.5 cm filter paper disc impregnated with 20% urea and 0.5% bromocresol purple was placed on the surface of a glucose fermentation plate after inoculation with a multipoint replicator and overnight incubation. This method was compared with the commercially prepared Mast urea agar (Multipoint) and Fuscoe's Urea Plate Medium. A total of 240 routine isolates of Enterobacteriaceae were tested for urease activity using the three methods. Sixty five isolates were positive by the three methods while 33 isolates gave differing results. The urea disc method was more sensitive for detecting urease activity in isolates of Klebsiella species, Morganella morganii, and Yersinia enterocolitica. It also overcame the problem associated with the other two media of diffusion of alkali end products through the medium.

Bacteriological Techniques↗
PubMedDate not supplied

Effect of different beta-lactams in combination with beta-lactamase inhibitors in the presence or absence of tobramycin against some enterobacteriaceae producing extended-spectrum beta-lactamases.

Extended-spectrum beta-lactamase (ESBL) production among members of the family Enterobacteriaceae generally involves resistance to oxyimino-cephalosporins and monobactams, while implying different susceptibility profiles with other antimicrobial agents. We have investigated the activity of some beta-lactam antibiotics, alone or in double and triple combinations with beta-lactamase inhibitors, in the presence or absence of tobramycin (TOB), against some Enterobacteriaceae producing ESBL by means of time-kill curves. Antimicrobials employed were ceftazidime (CAZ), cefotaxime (CTX), TOB, ampicillin (AMP), ampicillin-sulbactam (ASL), amoxicillin (AML), amoxicillin-clavulanic acid (AMC), piperacillin (PIP) and piperacillin-tazobactam (TZP), at 1/4 minimum inhibitory concentration for susceptible strains and at achievable serum concentrations for resistant strains. Only the combinations CTX-ASL, CAZ-ASL and PIP-ASL were synergistic, both at 6 and 24 h, on some strains of Klebsiella species.

Anti-Bacterial Agents↗
PubMedDate not supplied

Comparative activity of piperacillin/tazobactam against clinical isolates of extended-spectrum beta-lactamase-producing Enterobacteriaceae.

beta-Lactam resistance on the part of the Enterobacteriaceae causes serious therapeutic problems in our institutions due to their production of extended-spectrum beta-lactamases (ESbetaLs). We studied the in vitro activity of beta-lactam/beta-lactamase inhibitor combinations and third-generation cephalosporins and monobactams against 71 clinically relevant Enterobacteriaceae which produced TEM- and SHV-derivative ESbetaLs. Of the single drugs and combinations tested, piperacillin/tazobactam proved to be the most effective. Piperacillin/tazobactam was highly active against Proteus mirabilis, with minimum inhibitory concentrations (MICs) ranging from 0.125 to 16 microg/ml; Escherichia coli (MICs from 2 to 16 microg/ml) and Serratia marcescens (MICs from 4 to 8 microg/ml), while its activity against Klebsiella pneumoniae ESbetaL producers turned out to be closely related to the type and the amount of enzyme produced, the MIC ranging from 1 to 128 microg/ml. The antibacterial activity of piperacillin/tazobactam was stronger than that of ticarcillin/clavulanate, ceftriaxone, cefotaxime, ceftazidime and aztreonam, and the combination shared favorable in vitro activity properties against the ESbetaL producers with imipenem which, however, should be kept as reserve product.

Clavulanic Acids↗
PubMedDate not supplied

Taurolidine: in vitro activity against multiple-antibiotic-resistant, nosocomially significant clinical isolates of Staphylococcus aureus, Enterococcus faecium, and diverse Enterobacteriaceae.

Taurolidine at < or = 1,250 micrograms/ml killed all 37 isolates of multiple-antibiotic-resistant Staphylococcus aureus (n = 9), Enterococcus faecium (n = 17), and Enterobacteriaceae (n = 11). Time-kill experiments disclosed that bovine serum (65% v/v) only marginally retarded the bactericidal activity of 2,000 and 1,000 micrograms/ml of taurolidine against the various strains. Taurolidine at 2,000 micrograms/ml did not antagonize the bactericidal activity of 50% (v/v) fresh human serum against promptly and delayed serum-sensitive test strains of Escherichia coli and Serratia marcescens. In the presence of 65% (v/v) of fresh defibrinated human blood from two donors, however, the bactericidal activity of this antimicrobial compound was delayed, i.e., manifested only following extended (overnight) incubation, against staphylococcal and enterococcal isolates, though less so in the case of Enterobacteriaceae. Taurolidine at 2,000 micrograms/ml killed ingested, i.e., intraphagocytic bacteria of human-serum-resistant S. marcescens strains CDC 06:H3 and P016:H-.

Anti-Bacterial Agents↗
PubMed1997

Isolation of Enterobacteriaceae from the mouth and potential association with malodor.

Bad breath is a common phenomenon, usually the result of bacterial metabolism in the oral cavity. It is generally accepted that Gram-negative bacteria are responsible for this problem, largely through degradation of proteinaceous substances. In initial experiments, screening of malodorous isolates following outgrowth of samples obtained from saliva, periodontal pockets, and the tongue dorsum yielded enterobacterial isolates. Clinical studies were conducted to examine the prevalence of such bacteria in four different populations: orthodontic patients, malodor clinic patients, complete-denture wearers, and a healthy young population. The prevalence of Enterobacteriaceae in the oral cavities of the denture-wearing population was very high (48.0%) as compared with the other groups: 27.1% in the malodor clinic patients, 16.4% in the normal population, and 13% among orthodontic patients. Isolates of Klebsiella and Enterobacter emitted foul odors in vitro which resembled bad breath, with concomitant production of volatile sulfides and cadaverine, both compounds related to bad breath. When incubated on a sterile denture, enterobacterial isolates produced typical denture foul odor. Isolates exhibited cell-surface hydrophobic properties when tested for adhesion to acryl and aggregation with ammonium sulphate. The results, taken together, suggest that Klebsiella and related Enterobacteriaceae may play a role in denture malodor.

Adolescent↗
PubMed1996

In vitro activity of meropenem against ciprofloxacin-resistant enterobacteriaceae and Pseudomonas aeruginosa.

The in-vitro susceptibilities of a total of 174 ciprofloxacin-resistant Enterobacteriaceae and Pseudomonas aeruginosa were determined. According to the BSAC and NCCLS breakpoints, meropenem, aztreonam, ceftibuten, ceftazidime, imipenem and cefotaxime were the most active (> 90%) antimicrobial agents tested against Enterobacteriaceae. Susceptibility of these strains to piperacillin/tazobactam, cefpodoxime and cefixime (84.96%) was higher than that to tobramycin, gentamicin and fosfomycin (50-75%). More than 90% of P. aeruginosa were susceptible to meropenem when both interpretative susceptibility breakpoint criteria were used. Piperacillin, piperacillin/tazobactam and ceftazidime were active against 50-75% of the same strains. Meropenem was the most active antimicrobial tested against all ciprofloxacin-resistant clinical isolates assayed.

Anti-Bacterial Agents↗
PubMed1985

Changes during travel in the composition and antibiotic resistance pattern of the intestinal Enterobacteriaceae flora: results from a study of mecillinam prophylaxis against travellers' diarrhoea.

A randomized double-blind study was carried out in a group of Danish students visiting Mexico for 2 weeks to investigate the efficacy of mecillinam when given orally in preventing travellers' diarrhoea. The subjects took either 200 mg mecillinam daily as a single dose or placebo for 14 days. Nine (56%) out of 16 taking placebo and 3 (19%) out of 16 taking mecillinam developed travellers' diarrhoea (p less than 0.05). The pathogenic aetiology was not ascertained. A complete change in the Enterobacteriaceae flora took place during travel. A highly antibiotic-resistant Enterobacteriaceae flora was acquired in Mexico in subjects on mecillinam prophylaxis as well as on placebo. Selection of mecillinam-resistant bacteria was minimal.

Adult↗
PubMed1985

The activity of temocillin against Enterobacteriaceae, Pseudomonas and Haemophilus influenzae.

The in vitro antimicrobial activity of temocillin against 130 strains of Enterobacteriaceae and 27 strains of Pseudomonas and other related Gram-negative organisms was compared with carbenicillin, mezlocillin and piperacillin. Temocillin was compared with ampicillin against 76 strains of Haemophilus influenzae. More than 90% of Enterobacteriaceae including 65 carbenicillin-resistant strains were inhibited by 8 mg/L of temocillin. Pseudomonas spp. were less susceptible to temocillin than to the other 3 penicillins. 35 out of 38 strains of beta-lactamase-producing H. influenzae were inhibited by 2 mg/L of temocillin. But with 38 ampicillin-sensitive and non-beta-lactamase-producing ampicillin-resistant strains, temocillin was slightly less active than ampicillin. There was no significant enhancement of temocillin activity by clavulanic acid against 20 strains of Gram-negative rods producing characterised beta-lactamases. The resistance to plasmid-mediated and chromosomal beta-lactamase extracts was also studied by bioassay method. No enzyme extracts tested could hydrolyse temocillin except that from one Flavobacterium strain.

Clavulanic Acid↗
PubMed2003

Effect of chemical dehairing on the prevalence of Escherichia coli O157:H7 and the levels of aerobic bacteria and enterobacteriaceae on carcasses in a commercial beef processing plant.

The objective of this experiment was to test the hypothesis that cleaning cattle hides by removing hair and extraneous matter before hide removal would result in improved microbiological quality of carcasses in commercial beef processing plants. To test this hypothesis, we examined the effect of chemical dehairing of cattle hides on the prevalence of Escherichia coli O157:H7 and the levels of aerobic bacteria and Enterobacteriaceae on carcasses. Samples from 240 control (conventionally processed) and 240 treated (chemically dehaired before hide removal) hides (immediately after stunning but before treatment) and preevisceration carcasses (immediately after hide removal) were obtained from four visits to a commercial beef processing plant. Total aerobic plate counts (APC) and Enterobacteriaceae counts (EBC) were not (P > 0.05) different between cattle designated for chemical dehairing (8.1 and 5.9 log CFU/100 cm2 for APC and EBC, respectively) and cattle designated for conventional processing (8.0 and 5.7 log CFU/100 cm2 for APC and EBC, respectively). However, E. coli O157:H7 hide prevalence was higher (P < 0.05) for the control group than for the treated group (67% versus 88%). In contrast to hides, the bacterial levels were lower (P < 0.05) on the treated (3.5 and 1.4 log CFU/100 cm2 for APC and EBC) than the control (5.5 and 3.2 log CFU/100 cm2 for APC and EBC) preevisceration carcasses. Prevalence of E. coli O157:H7 was lower (P > 0.05) on treated than on control preevisceration carcasses (1% versus 50%). These data indicate that chemical dehairing of cattle hides is an effective intervention to reduce the incidence of hide-to-carcass contamination with pathogens. The data also imply that any effective hide intervention process incorporated into beef processing procedures would significantly reduce carcass contamination by E. coli O157:H7.

Animals↗
PubMed2004

Occurrence and behavior of Enterobacteriaceae and enterococci in mediterranean dry sausages during ripening in a Pilot-Scale chamber.

The occurrence and evolution of Enterobacteriaceae, coliforms, Escherichia coli, and enterococci in 252 samples of six types of Mediterranean dry-ripened sausages during maturation was investigated. The changes of the pH values were also recorded. Samples were analyzed in three steps of the ripening process: fresh product, first drying stage, and finished product. In all six sausages, Enterobacteriaceae, coliforms, and E. coli counts were characterized by high initial concentrations that significantly decreased during ripening. However, the initial counts of enterococci remained stable throughout the experiments in all sausages types. The average pH values of finished sausages ranged from 4.54 to 5.31.

Animals↗
PubMed1977

In vitro susceptibility of cephalothin-resistant Enterobacteriaceae to cefoxitin and BL-S786.

The in vitro antibacterial activity of two agents relatively resistant to beta-lactamases, BL-S786 and cefoxitin, was tested against 123 recent different clinical isolates of cephalothin-resistant Enterobacteriaceae. BL-S786 showed considerable activity against Escherichia coli and lesser activity against Klebsiella pneumoniae with, respectively, 68% and 41% inhibited at 32 microng/ml. Cefoxitin showed more activity in vitro against E. coli, K. pneumoniae, Serratia marcescens and Providencia stuartii. Cefoxitin appears to be a more promising agent for treating infections caused by cephalothin-resistant Enterobacteriaceae.

Cefoxitin↗
PubMed1984

Yokenella regensburgei gen. nov., sp. nov.: a new genus and species in the family Enterobacteriaceae.

The name Yokenella gen. nov. is proposed for a group of organisms in the family Enterobacteriaceae isolated from clinical sources and insects. Yokenella is a gram-negative, oxidase-negative, fermentative, motile rod possessing the characteristics of the family Enterobacteriaceae and the guanine plus cytosine contents of the DNA range from 58.0 to 59.3 mol%. Biochemical characteristics of this group and DNA hybridization studies indicate that the 11 strains studied here comprise a separate species which should be best placed in a new genus. This single DNA hybridization group is named Yokenella regensburgei sp. nov. The type strain of Y. regensburgei is NIH 725-83 (JCM 2403).

Animals↗
PubMed2002

Salmonella and other Enterobacteriaceae in dairy-cow feed ingredients: antimicrobial resistance in western Oregon.

Several studies have suggested an association between the use of antimicrobial agents in animal feeds and an increased risk that humans will contract resistant strains of bacteria such as Salmonella species, Escherichia coli, and other enteric isolates. The authors of this study evaluated whether animal feeds might serve as sources of antimicrobial-resistant bacteria, especially bacteria that are pathogenic to humans. From July through August 1998, samples of feed ingredients were collected from a total of 50 feed piles located on 12 dairy farms in western Oregon. From a subset of 10 piles, repeated samples were collected over time until each pile was depleted. Analysis of the samples indicated that 42.0 percent of all 50 piles and 60.0 percent of the piles from which there was repeated sampling were presumptive positive for Salmonella. Sixty-two percent of 50 Enterobacteriaceae isolates showed ampicillin resistance, and 10.0 percent displayed tetracycline resistance. Other bacteria displayed varying degrees of resistance to ampicillin, streptomycin, tetracycline, or a combination of these antimicrobials. The extent of antimicrobial-resistant Enterobacteriaceae in feed ingredients observed in this study raises significant concerns about the potential for human health risks from food-producing animals such as dairy cows.

Animal Feed↗
PubMed2002

[Extended-spectrum beta-lactamase detection in Enterobacteriaceae and antibiotic susceptibility analysis].

OBJECTIVE: To detect the extended-spectrum beta-lactamases (ESBLs) in family Enterobacteriaceae and analyze the antibiotic susceptibility of those ESBLs-producing strains. METHODS: ESBLs were determined by the double-disk confirmatory test and 8 antibiotic susceptibilities were tested with the disk disffusion method in those strains producing ESBLs. RESULTS: Forty-seven ESBLs-producing strains comprised of 25 of E. coli, 14 of K. pneumoniae, 5 of E. cloacae, 1 of K. oxytoca, 1 of K. rhinoscleromatis, and 1 of S. liquefaciens. The susceptibility rates of those strains were: 100% for imipenem and meropenem, 89.4% for piperacillin/tazobactam, 72.4% for cefoxitin and 65.9% for cefotetan. CONCLUSION: E. coli and K. pneumoniae are the prime strains producing ESBLs in Enterobacteriaceae. Imipenem and meropenem are the best drugs to deal with those ESBLs-producing strains. Piperacillin/tazobactam is better than cephamycins and other beta-lactama/beta-lactamase inhibitor combination.

Anti-Bacterial Agents↗
PubMed2003

Extended-spectrum beta-lactamase producing enterobacteriaceae in a tertiary care hospital in Trinidad and Tobago.

Extended-spectrum beta-lactamase (ESBL) mediated resistance to third generation cephalosporins, amongst the family Enterobacteriaceae, is emerging worldwide. This is the Caribbean's first survey on ESBL production, and was conducted during two six-month periods in 1998 and 2001, in a tertiary health institution in Trinidad and Tobago. Consecutive ampicillin resistant isolates of the family Enterobacteriaceae from in-patients were screened for resistance to third generation cephalosporins, and for ESBL production. The proportion of isolates found to be ESBL producers was similar in both samples (40 of 560 and 23 of 361). Overall, ESBL production was more frequent in enterobacter, citrobacter and proteus (and related organisms) than in Klebsiella and Escherichia (11.2% and 4.6%, respectively, p < 0.001). In the 1998 sample, this proportion (9.8% versus 5.8%) was significant (p < 0.05), but the difference was more marked in the 2001 sample (13.6% versus 2.9%, p < 0.001). Continued distribution of these resistant bacterial strains is of concern. In the Caribbean region, more laboratory surveillance and increased infection control vigilance are recommended, with focus on specific genera in the family.

Enterobacteriaceae↗
PubMed1992

[Occurrence of P.fimbrii in strains from selected genera of Enterobacteriaceae].

This study was aimed at recognition of frequency of occurrence of P fimbriae in strains of Escherichia coli isolated from samples of feces of children with symptoms of diarrhoea and at search of these adhesions in strains representing other than Escherichia genera of Enterobacteriaceae strains. One hundred forty laboratory strains were investigated. They belonged to genus Citrobacter, Enterobacter, Hafnia, Klebsiella, Morganella, Proteus, Providencia, Salmonella, Shigella, and Yersinia. Also were tested 1277 colonies of enteric rods isolated from the MacConkey's medium inoculated with samples of feces from 163 children with symptoms of diarrhoea. Mannose-resistant active hemagglutination test was performed with human group O erythrocytes and guinea pig erythrocytes stabilized with glutaraldehyde. Presence of P fimbriae was detected by the slide latex test with latex covered by P1 glycoprotein. Among 140 laboratory strains of Enterobacteriaceae in 21 strains (3-E. cloaceae, 2-Hafnia, 13-K. pneumoniae, 2-P. rettgeri and in one strains of Providencia) presence of MRHA adhesins was demonstrated. Nine of these strains (2-Hafnia, 5-K. pneumoniae and 2-P. rettgeri) reacted specifically in the latex test. Among 1142 colonies of E. coli isolated from children with symptoms of diarrhoea, 326 colonies belonged to 13 EPEC serotypes. With 118 (36.2%) of EPEC colonies a positive result of MRHA reaction was found with human erythrocytes and 34 (10.4%) with guinea pig erythrocytes. Positive latex test was obtained with 77 (23.6%) colonies. All these colonies possessed MRHA adhesins. Remaining 816 colonies of E. coli strains did not represent microorganisms belonging to serotypes accepted as enteropathogenic. From 112 (13.7%) colonies out of 816 not belonging to EPEC, positive results was obtained in the MRHA test with human erythrocytes and this was the case also with 41 (5.0%) colonies in MRHA reaction with application of guinea pig erythrocytes. The latex test was positive in 65 (7.9%) colonies of E. coli. From remaining 135 colonies other than E. coli, positive result of latex test of presence of P fimbriae was obtained with 54 (40.0%) colonies, including 14 colonies of E. cloacae, 23-K. pneumoniae and 17-K. oxytoca. In all these strains presence of MRHA adhesins was demonstrated. These investigations demonstrated that among EPEC strains significantly more frequently, than not belonging to these serotypes of E. coli, MRHA adhesins, including P fimbriae was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Child↗
PubMed1992

Species-differences in the pH-activity pattern of acid phosphatase in the family Enterobacteriaceae.

Nonspecific phosphatase activities were surveyed comparing major species of the family Enterobacteriaceae. The strains were subjected to a whole cell assay system with paranitrophenyl phosphate as substrate over a wide pH range and with a standardized number of bacterial cells. The overall results suggest that the general shape of the pH activity curve and the location of peaks (pH optimum) can be employed as a supplementary criterion to characterize species of Enterobacteriaceae.

Acid Phosphatase↗