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PubMed1995

Isolation and partial characterization of yeast mannan hydrolysing enzymes from bacterial isolates.

A range of aerobic, mesophilic bacterial strains capable of producing extracellular alpha-mannanase and alpha-mannosidase enzymes were isolated from various natural habitats using yeast cell wall material as the selective medium. Five of them were capable of producing extracellular alpha-mannosidase and alpha-mannanase on yeast mannan as the sole carbon substrate, and they were tentatively identified to the genus level as Arthrobacter, Streptomyces, Pseudomonas, Bacillus and Acinetobacter. Among these strains, Arthrobacter M-02 showed the highest biosynthetic activity of the enzymes. The crude enzyme preparations from the strains were active at pH 4 to 9, reaching a maximum activity between 5.5 and 6.8. The crude Arthrobacter M-02 alpha-mannosidase was more thermostable than that of the other strains, but the alpha-mannanase of the strain was thermolabile.

Acinetobacter↗

PubMed2006

Dereplication by automated ribotyping of a competitive exclusion culture bacterial isolate library.

Concerns over the development of antibiotic-resistant bacteria within the food animal industry have intensified the search for natural approaches to the prevention and treatment of bacterial diseases. Competitive exclusion cultures are the foundation of a disease-management strategy based on the use of benign bacterial strains to prevent the establishment of pathogenic bacteria within a specific host. Differentiation of phenotypically ambiguous isolates is a critical step in establishing a manageable library of bacteria for use in the development of defined competitive exclusion cultures. We used automated ribotyping techniques to dereplicate a large collection of phenotypically ambiguous isolates from a continuous-flow competitive exclusion culture. A total of 157 isolates were screened following an EcoRI restriction enzyme digestion. The 157 isolates were resolved into 23 ribogroups, which represents an 85% reduction in the number of isolates in the bacterial isolate library. Seventy-six percent of the isolates fit into one of five ribogroups. This work demonstrated that automated ribotyping is an effective and efficient tool for dereplication of diverse bacterial isolate libraries.

Antibiosis↗

PubMed1992

In vitro activity of Ro 23-9424, a dual-action antibacterial agent, against bacterial isolates from cancer patients compared with those of other agents.

The in vitro activity of Ro 23-9424 against bacterial isolates from patients with cancer was compared with those of fleroxacin, ciprofloxacin, cefoperazone, and ceftazidime. Ro 23-9424 inhibited the majority of the members of the family Enterobacteriaceae and all Aeromonas isolates at a concentration of less than or equal to 1.0 micrograms/ml. It was also active against Acinetobacter spp. and Haemophilus influenzae, including beta-lactamase-producing strains. The MIC for 90% of isolates (MIC90) of Pseudomonas aeruginosa was 16.0 micrograms/ml. All group A and B streptococci were inhibited by less than or equal to 0.25 micrograms/ml, and 90% of group G streptococci and Streptococcus pneumoniae were inhibited by 1.0 micrograms/ml. All methicillin-susceptible strains of Staphylococcus aureus and 60% of methicillin-resistant strains were susceptible to 2.0 micrograms of Ro 23-9424 per ml, whereas the MIC90 for Staphylococcus epidermidis and Staphylococcus hominis isolates was 4.0 micrograms/ml. Staphylococcus haemolyticus and Enterococcus spp. were less susceptible; MIC90s for them were 16.0 and 32.0 micrograms/ml. Ro 23-9424 has a broad antibacterial spectrum and potential utility for therapy of infections in cancer patients.

Anti-Infective Agents↗

PubMed1998

In vitro activities of clinafloxacin against contemporary clinical bacterial isolates from 10 North American centers.

Clinafloxacin was more active than ciprofloxacin against 4,213 aerobic and facultative anaerobic bacterial isolates from 10 medical centers, as tested by broth microdilution and disk diffusion methods. The percentage of 201 anaerobes susceptible to clinafloxacin by broth microdilution was comparable to cefoxitin. Our data support the proposed disk diffusion interpretive criteria for aerobic bacteria with 5-microg clinafloxacin disks.

Anti-Infective Agents↗

PubMed2005

Antibiotic prescribing in response to bacterial isolates in the intensive care unit.

This study aimed to identify potential knowledge-performance gaps in antibiotic prescribing for bacterial isolates in the Intensive Care Unit (ICU) in order to guide the development of interventions such as antibiotic policies, decision support, and improved systems for communication between the laboratory and the bedside. A prospective observational cohort study of all patients admitted to a mixed medical/surgical ICU was undertaken over a six-month period in an Australian adult tertiary hospital. From a cohort of 524 patients, 108 had 303 isolates that were eligible for inclusion. Overall, 14.3% and 30.8% of sterile and non-sterile isolates respectively were associated with inadequate initial antibiotic therapy after identification of the bacteria. After sensitivity results were available inadequate directed therapy was observed in 4.0% and 21.3% of sterile and non-sterile isolates respectively. Problems were most commonly associated with isolates of Pseudomonas spp., Stenotrophomonas spp., Acinetobacter spp., S. aureus, enterococci and group III Enterobacteriaceae. Inadequate antibiotic therapy was found to be independently associated with prolonged length of ICU stay. Narrower spectrum antibiotic therapy was potentially available for 30% of isolates after sensitivity results were known. We conclude that there is scope to improve antibiotic prescribing in the ICU by providing clinicians with access to information regarding local susceptibility patterns and intrinsic resistance of bacteria, and spectra of antibiotic cover. Timely notification of laboratory results at the point of care may also facilitate improved prescribing performance.

APACHE↗

PubMed2000

Classification of a bacterial isolate, from pozol, exhibiting antimicrobial activity against several gram-positive and gram-negative bacteria, yeasts, and molds.

A bacterial isolate, designated CS93, capable of producing a broad-spectrum antimicrobial compound(s) effective against gram-positive and gram-negative bacteria, yeasts, and molds was isolated from pozol, a fermented maize product. This strain was phenotypically similar to another pozol isolate that was previously designated as Agrobacterium azotophilium by other investigators. By using biochemical, phenotypic, and 16S rRNA sequence analysis, both pozol isolates were identified as members of the genus Bacillus, possibly a variant of Bacillus subtilis. While the antimicrobial compound(s) was initially produced only on a solid medium, parameters were identified for production in broth. The compound(s) was heat stable (121 degrees C for 15 min), exhibited activity over a wide pH range (pH 3 to pH 11), and was inactivated by pronase E. The antimicrobial compound(s) was bactericidal and bacteriolytic against Escherichia coli V517, bacteriostatic against Micrococcus luteus, and fungistatic against Saccharomyces cerevisiae. The inhibitory compound(s) could possibly serve as a food biopreservative.

Animals↗

PubMed2000

Antimicrobial-resistance trends in bacterial isolates from companion-animal community practice in the UK.

We conducted a longitudinal, retrospective investigation of antimicrobial resistance in bacterial isolates obtained from canine and feline clinical cases in veterinary community practice in UK (1989-1997). Individual-drug resistance was examined using isolates of Escherichia coli and Staphylococcus spp. as Gram-negative and Gram-positive indicator organisms, respectively. The annual prevalence of resistance was calculated for each organism to each of nine (for E. coli) and 11 (for Staphylococcus spp.) selected antimicrobials. The annual prevalence of multiple-drug resistance (MDR) was calculated for E. coli, Proteus spp., Pseudomonas spp., staphylococci and streptococci. Using a chi-square test for trend, significant rising trends were identified in individual resistance of E. coli to clavulanate-amoxycillin and streptomycin, and in MDR of E. coli, Proteus spp. and Pseudomonas spp. Declining trends were identified in individual resistance of Staphylococcus spp. to ampicillin and penicillin. Comparison with previously reported results from a contemporaneous investigation of companion-animal hospital patients indicated that selection pressures acting on the two populations overlapped but were not identical.

Animals↗

PubMed1977

Cefuroxime, a new parenteral cephalosporin: collaborative in vitro susceptibility comparison with cephalothin against 5,887 clinical bacterial isolates.

Cefuroxime, a new parenteral cephalosporin was compared with cephalothin by broth microdilution susceptibility testing against 5,887 routine clinical bacterial isolates in four large clinical laboratories. The minimal inhibitory concentrations (MICs) of cefuroxime against the Enterobacteriaceae were consistently lower than those of cephalothin. This was most striking among the Enterobacter species, which were generally susceptible to cefuroxime (MIC </= 8 mug/ml), but resistant to cephalothin. Similar results occurred with Haemophilus species, Acinetobacter anitratus, meningococci, and Aeromonas hydrophilia, but Pseudomonas species and enterococci were resistant to high concentrations of both drugs. Streptococci showed slightly greater susceptibility to cefuroxime than to cephalothin. By contrast, staphylococci were more susceptible to cephalothin. Bacteroides fragilis was resistant to cefuroxime, but other anaerobes were generally susceptible.

Bacteria↗

PubMed2004

Rapid screening and dereplication of bacterial isolates from marine sponges of the sula ridge by intact-cell-MALDI-TOF mass spectrometry (ICM-MS).

Rapid grouping of bacterial isolates is critical in comprehensive microbial studies of environmental samples or screening programmes e.g. in unknown marine environments where large numbers of strains have to be isolated on different growth media. Sets of bacteria have been cultured from the marine sponges Isops phlegraei, Haliclona sp. 1, Phakellia ventilabrum and Plakortis sp. growing at a depth of about 300 m on the Sula Ridge close to the Norwegian coast. We employed Intact-Cell MALDI-TOF (ICM) mass spectrometry to achieve a rapid proteometric clustering of a subset of the strain collection including 456 isolates. Cluster analysis of mass spectra resolved the strains into 11 groups corresponding to species of Alteromonas (15), Bacillus (3), Colwellia (31), Erythrobacter (19), Marinobacter (14), Marinococcus (6), Pseudoalteromonas (297), Pseudomonas (56), Roseobacter (3), Sphingomonas (2) and Vibrio (10) as verified by 16 S rDNA analysis. A further discrimination into subgroups was demonstrated for different isolates from the genus Pseudoalteromonas. The approach described here permits the rapid identification of isolates for dereplication, and the selection of strains representing rare species for subsequent characterization.

Animals↗

PubMed1993

Highly presumptive identification of bacterial isolates associated with the recent Canada-wide mastitis epizootic as Nocardia farcinica.

A highly presumptive identification of Nocardia farcinica was made of 47 bacterial isolates. Fifteen isolates from Alberta, 9 from Ontario, and 2 each from New Brunswick, Newfoundland, and Nova Scotia were from clinical cases involved in the Canadian mastitis epizootic. Seventeen additional isolates from Alberta were recovered from farm milk bulk tanks from herds found to have cows involved in the epizootic. All isolates were shown by high-performance liquid chromatography to possess mycolic acids of a size consistent with the genus Nocardia. All isolates were resistant to a concentration of 5 micrograms/mL of mitomycin C. Forty-five isolates grew well and 2 showed reduced growth in the presence of 50 micrograms/mL of kanamycin acid sulfate. Forty-six isolates were resistant to 5-fluorouracil at a concentration of 20 micrograms/mL. All isolates were resistant to lysozyme. Resistance to these compounds supported the placement of the isolates in the genus Nocardia. Thirty-five isolates produced strong beta-galactosidase reactions and 12 showed weak reactions. The demonstration of beta-galactosidase activity further supports the identification of the isolates as nocardiae. Attempts to identify the bacteria to species by high-performance liquid chromatography of mycolic acid esters were frustrated, since two species of Nocardia were found to have indistinguishable mycolic acid patterns. The physiological and growth characteristics of the isolates were consistent with Nocardia farcinica.

Animals↗

PubMed1984

The activity of enoxacin against clinical bacterial isolates in comparison with that of five other agents, and factors affecting that activity.

The activity of enoxacin against 362 clinical bacterial isolates in comparison with norfloxacin, nalidixic acid, ampicillin, latamoxef (moxalactam) and gentamicin was tested by an agar dilution method. Typical MICs for enterobacteria lay between 0.12 and 1.0 mg/l. Enterobacter spp. and Serratia spp. tended to be more resistant. Enoxacin was also active against Pseudomonas aeruginosa (mean MIC 0.5 mg/l) and highly active against fastidious Gram-negative aerobes. Typical MICs for Staphylococcus aureus were 1-2 mg/l while streptococci were more resistant (16-32 mg/l). Enoxacin had no useful activity against Bacteroides fragilis and Clostridium perfringens. Enoxacin was generally more active at pH 8 than pH 6, and in broth than in urine. It was bactericidal in its action. Daily serial passage from growth in broth containing enoxacin caused decreased sensitivity which was limited to four- to 16-fold greater than the original MIC. Enoxacin was about half as active as norfloxacin against enterobacteria, equally active against staphylococci, and some two to four times less active against streptococci.

Bacteria↗

PubMed2000

In vitro activity of gemifloxacin against contemporary clinical bacterial isolates from eleven North American medical centers, and assessment of disk diffusion test interpretive criteria.

A total of 5499 contemporary clinical bacterial isolates were tested for susceptibility to gemifloxacin and four comparison agents by the broth microdilution method. Gemifloxacin activity against Enterobacteriaceae was generally comparable to that of ciprofloxacin and trovafloxacin, but because the gemifloxacin susceptible MIC breakpoint is lower, the percent susceptible to gemifloxacin was less than that to the other quinolones for some species. All agents were less active against Pseudomonas spp. Gemifloxacin was the most active agent tested against Gram-positive species, though Corynebacterium jeikeium and vancomycin-resistant enterococci were uniformly resistant to all agents tested. With staphylococci, a bimodal distribution of gemifloxacin MICs corresponded with susceptibility or resistance to ciprofloxacin. The significance of ciprofloxacin-resistant staphylococci that have susceptible gemifloxacin MICs is not known at this time. Disk diffusion tests were performed simultaneously with gemifloxacin and trovafloxacin as a control drug. Gemifloxacin MIC-zone diameter scattergrams indicated that interpretive discrepancy rates based on previously proposed criteria when using < or = 0.5 microg/ml as the susceptible MIC breakpoint was within acceptable limits. However, with the currently proposed MIC breakpoint of < or = 0.25 microg/ml, tentative zone diameter breakpoints of > or = 22 mm for susceptible, 19-21 mm for intermediate and < or = 18 mm for resistant are proposed.

Anti-Infective Agents↗

PubMed1986

Evaluation of a rapid inoculum standardization system for antimicrobial susceptibility testing of bacterial isolates from the bovine mammary gland.

A commercially available rapid inoculum standardization system (RISS) was compared to the broth inoculum standardization method (BIS) for antimicrobial susceptibility testing of bacterial isolates from the bovine mammary gland. Overall agreement between RISS and the BIS method was 95.9%. RISS bypasses the 2-8 h incubation period required by BIS, thus providing antimicrobial susceptibility test data in a more timely manner. RISS was determined to be an acceptable alternative method to the BIS method for preparation of standardized inoculum for antimicrobial susceptibility testing of bovine mammary gland isolates.

Animals↗

PubMed1994

[Dynamics in bacterial isolation and antigenemia in patients with infiltrative pulmonary tuberculosis].

A hundred patients with infiltrative pulmonary tuberculosis were studied. They were examined for bacterial isolates and mycobacterial antigens in the immune complexes. The isolates were detected in 76%. In most cases, isolation stopped 3 months following chemotherapy and in the absolute majority of cases (except one) 9 months after. Isolation of L-forms remained for a longer period of time, at month 6 of therapy there was an increase in the number of patients who were found to have L-forms of the bacteria. Most (97%) patients with infiltrative tuberculosis displayed mycobacterial antigens circulating in the immune complexes. Antigenemia retained in a considerable (40%) number of patients long (up to 9 months) and in most cases with the unfavourable course of the disease.

Adolescent↗

PubMed1984

In vitro activity of U-63196E, a new cephalosporin, against clinical bacterial isolates.

The in vitro activity of U-63196E, a new cephalosporin, was compared with those of other extended-spectrum cephalosporins and penicillins against clinical bacterial isolates. Against Pseudomonas aeruginosa, the activity of U-63196E was comparable to those of cefoperazone and piperacillin, each of which inhibited 90% of strains at concentrations of less than or equal to 16 micrograms/ml. The new drug also demonstrated activity against a variety of other bacterial species, but it was generally less active than cefotaxime, moxalactam, and cefoperazone against members of the family Enterobacteriaceae and staphylococci. The presence of any 1 of 10 plasmid-mediated beta-lactamases in a series of otherwise isogenic laboratory strains of P. aeruginosa resulted in a significant reduction in the activity of U-63196E in comparison with its activity against the parent strain, which lacks these enzymes. Combinations of U-63196E with tobramycin demonstrated bacteriostatic synergism against 11 of 20 clinical isolates of P. aeruginosa.

Anti-Bacterial Agents↗

PubMed1997

In-vitro activity of trovafloxacin against clinical bacterial isolates from patients with cancer.

The antibacterial activity of trovafloxacin was compared with that of ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin and norfloxacin against bacterial isolates from patients with cancer. In general, the activity of trovafloxacin was comparable to that of ciprofloxacin, levofloxacin and sparfloxacin against most Gram-negative isolates tested (minor differences in the activity of each agent against individual species were seen) and it was the most active agent tested against Stenotrophomonas maltophilia, inhibiting 80% of these isolates at <2.0 mg/L. Trovafloxacin was also the most active agent tested against Gram-positive organisms, including ciprofloxacin-susceptible strains and most ciprofloxacin- and methicillin-resistant staphylococci and enterococci. It was much more active than ciprofloxacin against streptococci, including Streptococcus pneumoniae and the viridans streptococci, and was also active against Bacillus cereus and Listeria monocytogenes, inhibiting all isolates at a concentration of <0.5 mg/L.

Anti-Infective Agents↗

PubMed1990

Susceptibility of bacterial isolates from AIDS patients to six fluoroquinolones.

The susceptibilities to ciprofloxacin, DR-3355 (S-(-)-ofloxacin), enoxacin, lomefloxacin, ofloxacin and PD127,391 of 69 significant bacterial isolates from HIV-positive patients at the City Hospital, Edinburgh have been determined. With the exception of the enterococci, most of the strains tested (including staphylococci, Escherichia coli and Pseudomonas aeruginosa) were susceptible to the fluoroquinolones. Ciprofloxacin was the most active of the clinically available drugs followed by ofloxacin, lomefloxacin and enoxacin. PD127,391 and DR-3355, the new fluoroquinolones tested, were at least as active as ciprofloxacin. Hence bacterial infections in AIDS patients should respond to fluoroquinolone therapy.

4-Quinolones↗

PubMed1994

Susceptibilities of bacterial isolates from patients with cancer to levofloxacin and other quinolones.

The antibacterial activity of levofloxacin was compared with those of ofloxacin and ciprofloxacin against bacterial isolates from patients with cancer. In general, levofloxacin was as active or was twofold more active than ofloxacin and was two- to fourfold less active than ciprofloxacin against most gram-negative pathogens. Against Pseudomonas aeruginosa, ciprofloxacin was the most active agent tested (MIC for 90% of isolates tested, 1.0 microgram/ml). Overall, all three agents had similar activities against gram-positive organisms and were moderately active against methicillin-susceptible Staphylococcus aureus and coagulase-negative staphylococci, Streptococcus species, and Enterococcus species.

Anti-Infective Agents↗