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PubMed2000

Beta-lactamase inhibitor combinations with extended-spectrum penicillins: factors influencing antibacterial activity against enterobacteriaceae and Pseudomonas aeruginosa.

Production of beta-lactamases is the most common mechanism by which gram-negative bacteria express resistance to beta-lactam antibiotics. One successful method of circumventing the threat of plasmid-encoded beta-lactamases is to combine inhibitors of these enzymes with a penicillin. Currently, four inhibitor-penicillin combinations are in clinical use: ampicillin-sulbactam, amoxicillin-clavulanate, ticarcillin-clavulanate, and piperacillin-tazobactam. Of these, ticarcillin-clavulanate and piperacillin-tazobactam have the broadest spectra of activity that includes Pseudomonas aeruginosa. Many factors influence the activity and pharmacodynamics of these combinations, including potency of both agents, pharmacokinetics of the inhibitor, type and quantity of beta-lactamase produced by the target bacterium, and potential for the inhibitor to induce expression of chromosomal cephalosporinases in the target bacterium. Although ticarcillin-clavulanate and piperacillin-tazobactam have similar spectra of activity, they have many differences. Most notable are increased potency of piperacillin against Enterobacteriaceae and P aeruginosa, increased activity of piperacillin-tazobactam against gram-negative pathogens producing penicillin-sensitive enzyme (PSE)-class beta-lactamase or hyperproducing other plasmid-encoded beta-lactamases, and the more favorable pharmacokinetics of tazobactam. In the treatment of P. aeruginosa infections, the potential for clavulanate to induce expression of chromosomal cephalosporinase and antagonize antibacterial activity of ticarcillin is a concern, especially in patients who lack protective host defenses. These are not concerns with piperacillin-tazobactam.

Clavulanic Acid↗

PubMed1995

The prevalence of Staphylococcus aureus, Enterobacteriaceae species, and Candida species and their relation to oral mucosal lesions in a group of 79-year-olds in Göteborg.

A subject sample comprising 100 persons (47 men and 53 women) 79 years of age and selected on a statistical basis (representing all persons of that age living in Göteborg) was the object of a general medical, clinical, and microbiologic study of the prevalence of microorganisms in the oral cavity known to cause opportunistic infections. A high prevalence of diseases and frequent medications were recorded among the participants. Staphylococcus aureus was present in five patients and Enterobacteriaceae species in only one individual. Candida albicans was not found in any samples from the palatal mucosa of the 25 individuals without dentures. Of 36 healthy denture wearers C. albicans was found in 9 (25%). In 39 persons with denture stomatitis C. albicans was obtained in 11 (28%) of the samples from the mucosa, 29 (74%) from the dentures, and 10 (26%) from the angulus oris. The prevalence of S. aureus, enteric rods, and C. albicans was low in the elderly population and, when present, correlated with the presence of dentures. No association with the patients' general health or drug use was obtained.

Aged↗

PubMed1988

Iron and virulence in the family Enterobacteriaceae.

The ability of bacterial pathogens to acquire iron in the host is an essential component of the disease process. Pathogenic Enterobacteriaceae spp. may either scavenge host iron sources such as heme or induce high-affinity iron-transport systems to remove iron from host proteins. The ease with which iron is acquired from the host will be at least partially determined by the iron status of the host at the time of infection. In response to infection, mammalian hosts reduce serum iron levels and withhold iron from the invading microorganisms. Thus the competition for iron is an active process which influences the outcome of a host-bacterial interaction.

Animals↗

PubMed1990

Biosynthesis of biotin-vitamers by family Enterobacteriaceae.

The biosynthesis of biotin-vitamers from various carbon sources by the members of the Enterobacteriaceae as one of the groups of intestinal bacteria was investigated. The biotin-vitamers synthesized in each case included one or more of dethiobiotin (main product), 7-keto-8-aminopelargonic acid, and biotin. True biotin was shown to be synthesized under aerobic conditions but not under anaerobic conditions by each of several strains belonging to one of the genera, Erwinia, Escherichia, Proteus, and Serratia, and using culture media containing one of galactose, peptone, Polypepton, or casamino acid. In addition, a biotin precursor, pimelic acid, was also synthesized by several bacteria utilizing carbon sources such as maltose, mannose, galactose, peptone, or casamino acid.

Biotin↗

PubMed1975

"Core" glycolipid of enterobacteriaceae: immunofluorescent detection of antigen and antibody.

The Re chemotype mutant of Salmonella minnesota R595 has a cell-wall glycolipid composed principally of 2-keto, 3 deoxyoctonate and Lipid A, which is an antigen widely shared by Enterobacteriaceae. High-titered antiserum against this antigen can be conjugated with fluorescein isothiocyanate for direct detection of this antigen in heterologous bacteria and staining of bacteria in tissue. Alternatively, the indirect immunofluorescence technique can be used for antigen detection on bacterial surfaces and in tissues, and this method can quantitate glycolipid antibody in mammalian sera. The latter may be particularly useful in serologic studies because, although the glycolipid antigen is a surface antigen and purified extracts can be used to coat latex particles, high-titered antisera will not agglutinate bacteria or coated latex particles.

Animals↗

PubMed1976

Swab and excised tissue sampling for total and Enterobacteriaceae counts of fresh and surface-frozen broiler skin.

Excised broiler skin tissue (12.3 cm 2 area) was (a) blended for various times up to 2 min. or (b) shaken 25, 50, or 75 times with or without sterile glass beads. Blending for 10 sec. or shaking 75 times with glass beads yielded the highest total plate count (TPC) and Enterobacteriaceae count (ENT). Counts did not significantly differ between these methods when freshly processed, unfrozen broiler skin was sampled. However, blending yielded significantly higher TPC and ENT than the conventional sampling procedure or swabbing a 12.3 cm. 2 area of the intact skin for 30 sec. with a calcium alginate swab. When sampling hard chilled (surface frozen) broiler skin, there was no significant difference between shaking and blending for TPC, but shaking gave a significantly higher ENT with less variation than blending. Blending, however, yielded significantly higher TPC and ENT counts than swabbing.

Animals↗

PubMed1992

The effect of air scrubbing on moisture pickup, aerobic plate counts, Enterobacteriaceae, and the incidence of salmonellae on artificially inoculated broiler carcasses.

Processed broiler carcasses were subjected to diffused air at 158.6 kPa (air scrubbing) in tap water to evaluate the potential of this treatment for improving the microbiological quality of read-to-cook poultry. Carcasses were inoculated with a marker strain of Salmonella typhimurium 5 min before treatment. The carcasses were removed after 30 min and sampled for aerobic plate counts (APC), Enterobacteriaceae (ENT) counts, for the presence of the marker organism, or for moisture pickup. The S. typhimurium were recovered from 32 of 40 control carcasses (water only), but from only 9 of 40 air-scrubbed samples. When carcasses were inoculated with fewer than 150 cells of the marker organism, air scrubbing was more effective in reducing the incidence of salmonellae (2 of 20 positive) than when levels were in excess of 150 cells (7 of 20 positive). A similar pattern was manifested with the water-rinsed carcasses rinsed without air injection (below 150, 12 of 20; above 150, 20 of 20). No significant differences were found in the APC and ENT counts. Moisture pickup was adversely affected by air scrubbing; control carcasses had a moisture pickup of 5.8%, whereas, air-scrubbed carcasses had a moisture pickup of 13.9%.

Analysis of Variance↗

PubMed1993

Research note: a modified most probable number technique to enumerate total aerobes, enterobacteriaceae, and Salmonella on poultry carcasses after the whole carcass rinse procedure.

A modified most probable number (MPN) technique utilizing a single 10-fold dilution series was tested to enumerate the microbiological population from the whole carcass rinse procedure for poultry. Diluent for the MPN series was a general nutrient broth. Resuscitation of damaged cells and pre-enrichment of low numbers of microorganisms was accomplished by the MPN media. The MPN dilution tubes positive for growth were used to calculate the total aerobic bacterial population. Subculturing with tetrathionate enrichment broth and subsequent plating to differential media were used to identify and enumerate Salmonella. Enterobacteriaceae were enumerated by subculture of the MPN positive tubes in brilliant green (BG) bile 2% broth supplemented with 1% dextrose that were then observed for gas production. The aerobic bacterial counts obtained by the modified MPN were similar, yet significantly higher than those obtained with the conventional plate count techniques (P < .05), and both were significantly higher than the three tube MPN counts.

Animals↗

PubMed2004

Prevalence of Escherichia coli O157 and levels of aerobic bacteria and Enterobacteriaceae are reduced when hides are washed and treated with cetylpyridinium chloride at a commercial beef processing plant.

The objective of this experiment was to test the potential of a combined water wash and cetylpyridinium chloride (CPC) treatment as a hide intervention applied to cattle in the holding pens of a processing plant immediately before stunning. Over 2 processing days, 149 control and 139 treated cattle were tested. Control cattle were processed in the normal manner. The treatment group was prewashed with water the day before harvest. Immediately before stunning, these cattle were sprayed twice with 1% CPC, first for 3 min, then for 1 min. Hides and preevisceration carcasses were sampled to determine aerobic plate counts, Enterobacteriaceae counts (EBC), and Escherichia coli O157 prevalence. The treatment reduced the prevalence of E. coli O157 on hides from 56% to 34% and the prevalence on preevisceration carcasses from 23% to 3%. The treatment decreased aerobic plate counts from 4.9 log CFU/100 cm2 to 3.4 log CFU/100 cm2 and EBC from 3.1 log CFU/100 cm2 to 2.0 log CFU/100 cm2 on preevisceration carcasses. The treatment of hides did not result in any detectable CPC contamination of the chilled carcasses. These data indicated that a 1% CPC treatment preceded by a water wash was capable of reducing hide prevalence of E. coli O157 from as high as 80% to less than 50%, resulting in preevisceration carcass prevalence of 5% or less. We conclude that water washing followed by an antimicrobial treatment, such as CPC, has great potential as an effective hide intervention step and should be further evaluated for implementation as a processing step after stunning and before hide removal.

Abattoirs↗

PubMed1999

In vitro activity of newer broad spectrum beta-lactam antibiotics against enterobacteriaceae and non-fermenters: a report from Austrian intensive care units. Austrian Carbapenem Susceptibility Surveillance Group.

We compared the in vitro activity of broad spectrum beta-lactam antibiotics against 573 gram-negative isolates (enterobacteriaceae and non-fermenters) collected between November 1996 and May 1997 from 9 laboratories serving intensive care units throughout Austria. MIC's (Minimal Inhibitory Concentration) were obtained with the E-test for meropenem, imipenem, ceftazidime, cefepime, cefpirome and piperacillin/tazobactam. Pseudomonas aeruginosa was the most frequently isolated organism (22%), followed by E. coli (19%), Klebsiella spp. (16%), and Enterobacter spp. (14%). Acinetobacter spp., Proteus spp., Serratia spp., Stenotrophomonas maltophilia, Citrobacter spp., Morganella morganii, Burkholderia cepacia and Salmonella enteritidis were isolated less frequently. Overall meropenem, imipenem and ceftazidime were the most active compounds in vitro, inhibiting 90%, 89%, and 87% of the isolates, respectively. Pseudomonas aeruginosa was inhibited by piperacillin/tazobactam in 89%, by cefepime in 87% and by ceftazidime in 85%. Imipenem, meropenem and cefpirome were less active (79%, 75% and 69% respectively). All E. coli strains were inhibited by meropenem, 99% were inhibited by imipenem, cefepime and cefpirome. Ceftazidime was active against 95% and piperacillin/tazobactam against 92% of E. coli. All Klebsiella spp. were inhibited by meropenem, cefepime and cefpirome. Imipenem inhibited 99% and ceftazidime 98% of the Klebsiella isolates. Piperacillin/tazobactam was active against 95% of Klebsiella spp. In vitro carbapenems are still the most active of all antibiotics tested. The relatively high resistance of Pseudomonas spp. and Acinetobacter spp. to carbapenems reflects the wide use of carbapenems during the last years. However, most bacterial isolates are still sensitive to the tested broad spectrum beta-lactams.

Acinetobacter↗

PubMed1975

Trimethoprim-resistant Enterobacteriaceae in urinary tract infection.

The incidence of trimethoprim-resistant Enterobacteriaceae has not increased since the introduction of the combination trimethoprim-sulfamethoxazole (TMP-SMX) into the clinical use at our centre in 1973. Using the minimum inhibitory concentration (MIC) as the index of trimethoprim resistance, this ranged from 1.6 to 800 mug/ml; for the majority of isolates it lay between 1.6 and 12.5 mug/ml. About half of these trimethoprim-resistant organisms were sensitive to sulfonamide. In vitro data suggest that organisms resistant to sulfonamide as well as to trimethoprim, where the MIC for the former drug is 3.1 mug/ml or less, will be susceptible to the combination. More resistant organisms, i.e., those for which the MIC of trimethoprim is 6.2 mug/ml or more, often appear quite resistent to the combination. There is no evidence that previous therapy with TMP-SMX is a significant predisposing factor to infection with these organisms, although there is a significant correlation between previous TMP-SMX therapy and infection with organisms with a high level of trimethoprim resistance. Organisms harbouring R-factor resistance or thymine-dependent mutants were not encountered during the course of this study.

Drug Combinations↗

PubMedDate not supplied

[Studies on haemolysins of "enterobacteriaceae" (author's transl)].

Haemolysin production of 1,103 strains of Enterobacteriaceae was investigated on trypticase soja agar containing washed horse erythrocytes. Nearly all haemolytic strains belonged to the genus Escherichia (103 haemolytic strains out of 349 examined). The 3 remaining haemolytic strains belonged to the genus Serratia (of which 244 strains were examined). Plasmidic determinism of haemolysis was demonstrated for six of the Hly+ E. coli strains, and these plasmids were transferred to E. coli K12, Salmonella typhia and S. typhi-murium. Investigations about coexistence of four of these plasmids with "metabolic" plasmids and with representatives of the plasmids compatibility groups presently known, showed that two of these plasmids were fi+ and belonged to the FIII group, and that two other were fi- and related to the I2 group. Thus, different plasmids can determine haemolysin-production in E. coli strains.

Coliphages↗

PubMed1975

[Nutrition and taxonomy of "Enterobacteriaceae" and related bacteria. I. Technical procedure for auxanograms (author's transl)].

Study of nutritional capacities of 186 strains of Enterobacteriaceae or related bacteria has been undertaken for a taxonomic purpose. In this paper, the auxanographic method is described and discussed. Unlike other techniques in which the medium is supplemented by each substrate, at fixed concentration, the method described here consists in achieving diffusion of the 146 substrates tested as sole source of carbon and energy, in a medium without other energetic substrate. The results of these tests will be described in a further paper.

Culture Media↗

PubMedDate not supplied

Sensitivity of Enterobacteriaceae strains to the third generation cephalosporins.

The aim of this study was to evaluate the in vitro activity of cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam against the clinical isolates of Enterobacteriaceae. MICROORGANISMS: A total of 973 enterobacteria isolated from clinical material (urine and faeces) were tested. Strains were collected during 1996-1998 period, in some centers of Eastern Romania. SENSITIVITY STUDY: MICs were performed using the agar dilution method following standardized techniques (NCCLS, 1994). Stock solutions of antibacterial agents were prepared from their respective powder forms, in concentrations ranging from 0.03 to 128 mg/ml. Our results show a good activity of the tested antimicrobials on Escherichia coli, Shigella spp and Klebsiella spp tested, and reveal a particular behaviour for Salmonella spp, characterized by a heterogenous susceptibility. In conclusion, cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam were active at low concentrations against tested isolates. Against Salmonella spp, these agents were less active: percent of resistant strains by beta-lactamase production was significant.

Cephalosporins↗

PubMedDate not supplied

[Detection of extended-spectrum beta-lactamases production in enterobacteriaceae strains].

Extended-spectrum beta-lactamases (ESBL) cause resistance to ceftazidime, ceftriaxone, cefotaxime and other cephalosporins. The ESBL enzymes are most often derivatives of beta-lactamases from the TEM or SHV group. The aim of our work was to study ESBL production by 35 ceftazidime-resistant strains. We selected these strains among 335 Enterobacteriaceae, isolated in Eastern Romania from healthy carriers and patients, between january-june 1999. To identify the studied strains we used API 20E and API 32E. The ESBL production was established by using both double disk synergy test (DDT) and EXPERT computer program of miniAPI (Bio Merieux). We revealed ESBL production in 26 strains when EXPERT program was used and only 23 when DDT was used. Our results suggest that miniAPI is a better method to study ESBL production than DDT.

Anti-Bacterial Agents↗

PubMed1975

[Nutrition and taxonomy of "enterobacteriaceae" and related bacteria. III. Nutritional characters and differentiation of the taxonomic groups (author's transl)].

A batch of 186 strains belonging to the families Enterobacteriaceae or Vibrionaceae has been studied by determination, for each strain, of the "versatility" towards 146 organic substrates tested as sole source of carbon and energy. This study allowed to work out a classification of these strains into the 32 classes which have been previously described. In the present paper the nutritional characters of these classes are reported. On the basis of these characters, the 32 classes may be regrouped into 7 groups, namely: (1.1) "Escherichia-Salmonella-Citrobacter", (1.2) "dystrophic Klebsielleae", (1.3) "eutrophic Klebsielleae", (2.1) "Shigella", (2.2) "Proteus", (2.3) "Aeromonas-Vibrio", (2.4) "Edwardsiella tarda-Aeromonas salmonicida-Plesiomonas shigelloides". Only 4 strains (about 2 percent) happened misclassified in this study where the taxa were assembled exclusively by means of nutritional characters. The number and the type of the substrates which can be used in each group are reported, as well as the nutritional characters which are possibly useful to differential diagnosis. The taxonomic considerations which may be deduced from this study are discussed.

Amino Acids↗

PubMedDate not supplied

[Types of secretion and regulation of the functional activity of molecules associated with the pathogenicity of Enterobacteriaceae].

Five types of nonhomologous systems of the export of protein molecules, known to exist in pathogenic bacteria, are characterized. The described secretion systems take part in the synthesis of not only toxic proteins, but also different adhesins and hydrolytic enzymes. In the export of Enterobacteriaceae toxins secretion types I, II, III and V are of importance. Characteristics of Sec-dependence at the stage of transport through the cytoplasmic membrane is the key sign in their differentiation. The functional activity of bacterial toxins and the level of toxigenicity expression are finely regulated signs, mediated by external signals. The systems for their regulation are relatively few in number and rather conservative. As shown in this study, the regulation of pathogenicity expression has no specific mechanisms. Moreover, it is regulated by common systems and mechanisms for the regulation of usual physiological processes.

Adhesins, Bacterial↗

PubMed1956

The Arizona group of enterobacteriaceae in animals and man; occurrence and distribution.

A summary of the occurrence and distribution of serotypes of the Arizona group of Enterobacteriaceae among animals and man is presented. In all, 1308 cultures have now been isolated and 96 serotypes identified. In the 75 cultures obtained from man, 21 serotypes have been found. Organisms of the Arizona group have been discovered in epizootic infections of animals in which the mortality was high. In man they have appeared both in sporadic cases and in well-defined outbreaks of disease. The bacteria have been found in blood cultures and localized infections as well as in the stools of persons affected with gastro-enteritis. The opinion that bacteria of the Arizona group are primary excitants of disease is stressed and evidence to support this view is presented.

Animals↗