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PubMedDate not supplied

Comparative in vitro activity of lomefloxacin (SC 47111 or NY-198) against fresh clinical bacterial isolates.

The in vitro antibacterial activity of a new difluorinated quinolone (lomefloxacin) was compared with that of ten selected antibiotics against 744 fresh bacterial isolates representing 32 species. Lomefloxacin was comparable to other quinolones tested against Enterobacteriaceae (MIC90, less than or equal to 0.25 micrograms/ml) and generally more effective than other compounds tested against Staphylococcus spp. and Pseudomonas aeruginosa with MIC90s of less than or equal to 2 and less than or equal to 4 micrograms/ml, respectively.

4-Quinolones↗

PubMed1973

Immersion refractometry of isolated bacterial cell walls.

Immersion-refractometric and light-scattering measurements were adapted to determinations of average refractive indices and physical compactness of isolated bacterial cell walls. The structures were immersed in solutions containing various concentrations of polymer molecules that cannot penetrate into wall pores, and then an estimate was made of the polymer concentration or the refractive index of the polymer solution in which light scattering was reduced to zero. Because each wall preparation was heterogeneous, the refractive index of the medium for zero light scattering had to be estimated by extrapolation. Refractive indices for walls suspended in bovine serum albumin solutions ranged from 1.348 for walls of the rod form of Arthrobacter crystallopoietes to 1.382 for walls of the teichoic acid deficient, 52A5 strain of Staphylococcus aureus. These indices were used to calculate approximate values for solids content per milliliter, and the calculated values agreed closely with those estimated from a knowledge of dextran-impermeable volumes per gram, dry weight, of the walls. When large molecules such as dextrans or serum albumin were used for immersion refractometry, the refractive indices obtained were for entire walls, including both wall polymers and wall water. When smaller molecules that can penetrate wall pores to various extents were used with Micrococcus lysodeikticus walls, the average, apparent refractive index of the structures increased as the molecular size of probing molecules was decreased. It was possible to obtain an estimate of 1.45 to 1.46 for the refractive index of wall polymers, predominantly peptidoglycans in this case, by extrapolating the curve for refractive index versus molecular radius to a value of 0.2 nm, the approximate radius of a water molecule. This relatively low value for polymer refractive index was interpreted as evidence in favor of the amorphous, elastic model of peptidoglycan structure and against the crystalline, rigid model.

Arthrobacter↗

PubMed1986

[In vitro activity of the combination ticarcillin-clavulanic acid on bacterial isolates in surgery].

The in vitro activity of ticarcillin in combination with clavulanic acid was tested, by disc diffusion, against 1,380 clinical bacterial isolates and was compared with that of ticarcillin alone. 83.8% of the isolates were susceptible to ticarcillin + clavulanic acid, whereas 56.6% were susceptible to ticarcillin alone. Minimal inhibitory concentrations (MIC) of ticarcillin in the presence of 4 micrograms/ml of clavulanic acid were determined against 157 ticarcillin resistant (MIC greater than 128 micrograms/ml) but ticarcillin + clavulanic acid susceptible strains of Gram negative bacilli and against 20 strains of beta-lactamase producing Staphylococcus aureus. With the addition of clavulanic acid, MICs of ticarcillin were respectively less than or equal to 16 micrograms/ml and less than or equal to 64 micrograms/ml for 50 and 90% of the Gram negative bacilli. All the Staphylococcus aureus were inhibited by concentrations of ticarcillin less than or equal to 1 microgram/ml.

Bacteria↗

PubMed1993

Comparative antimicrobial activity of lomefloxacin, norfloxacin, ofloxacin, ciprofloxacin and enoxacin against > 500 bacterial isolates.

An agar dilution technique was used to compare the antimicrobial activities of lomefloxacin, norfloxacin, ofloxacin, ciprofloxacin and enoxacin against 544 strains of bacterial isolates. Among the five quinolone agents tested, ciprofloxacin was the most active. Enoxacin was the most active after ciprofloxacin against Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Shigella spp., Yersinia enterocolitica, and Haemophilus influenzae with an MIC90 of < or = 0.25 micrograms/ml. Ofloxacin was the most active agent after ciprofloxacin against Klebsiella pneumoniae, Enterobacter cloacae, Citrobacter diversus, and Legionella pneumophila with an MIC of < or = 0.25 micrograms/ml. Ciprofloxacin inhibited Staphylococcus spp. and Streptococcus spp., at < or = 0.5 micrograms/ml and 2 micrograms/ml, respectively. Norfloxacin and enoxacin had the same antimicrobial activity (MIC90) against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus agalactiae and some other Gram-positive species, but these activities were weak when compared with ciprofloxacin. The results of this in vitro study show that ciprofloxacin is very active against Gram-negative and Gram-positive species.

Anti-Infective Agents↗

PubMed2000

Isolation and characterization of two new methanesulfonic acid-degrading bacterial isolates from a Portuguese soil sample.

Two novel bacterial strains that can utilize methanesulfonic acid as a source of carbon and energy were isolated from a soil sample collected in northern Portugal. Morphological, physiological, biochemical and molecular biological characterization of the two isolates indicate that strain P1 is a pink-pigmented facultative methylotroph belonging to the genus Methylobacterium, while strain P2 is a restricted methylotroph belonging to the genus Hyphomicrobium. Both strains are strictly aerobic, degrade methanesulfonate, and release small quantities of sulfite into the medium. Growth on methanesulfonate induces a specific polypeptide profile in each strain. This, together with the positive hybridization to a DNA probe that carries the msm genes of Methylosulfonomonas methylovora strain M2, strongly endorses the contention that a methanesulfonic acid monooxygenase related to that found in the previously known methanesulfonate-utilizing bacteria is present in strains P1 and P2. The isolation of bacteria containing conserved msm genes from diverse environments and geographical locations supports the hypothesis that a common enzyme may be globally responsible for the oxidation of methanesulfonate by natural methylotrophic communities.

Alphaproteobacteria↗

PubMed2001

Genomic approaches to typing, taxonomy and evolution of bacterial isolates.

The current literature on bacterial taxonomy, typing and evolution will be critically examined from the perspective of whole-genome structure, function and organization. The following three categories of DNA band pattern studies will be reviewed: (i) random whole-genome analysis; (ii) specific gene variation and (iii) mobile genetic elements. (i) The use of RAPD, PFGE and AFLP to analyse the whole genome will provide a skeleton of polymorphic sites with exact genomic positions as whole-genome sequence data become available. (ii) Different genes provide different levels of evolutionary information for determining isolate relatedness depending on whether they are highly variable (prone to recombination events and horizontal transfer), housekeeping genes with only a small number of single nucleotide differences between isolates or part of the rrn multigene family that is prone to intragenomic recombination and concerted evolution. Comparative analyses of these different gene classes can provide enhanced information about isolate relatedness. (iii) Mobile genetic elements such as insertion sequences, transposons, plasmids and bacteriophages integrate into the bacterial genome at specific (e.g. tRNA genes) or non-specific sites to alter band patterns produced by PFGE, RAPD or AFLP. From the literature it is not clear what level of genetic element duplication constitutes non-relatedness of isolates. A model is presented that incorporates all of the above genomic characteristics for the determination of isolate relatedness in taxonomic, typing and evolutionary studies.

Bacteria↗

PubMed2003

Usefulness of the MicroSeq 500 16S ribosomal DNA-based bacterial identification system for identification of clinically significant bacterial isolates with ambiguous biochemical profiles.

Due to the inadequate automation in the amplification and sequencing procedures, the use of 16S rRNA gene sequence-based methods in clinical microbiology laboratories is largely limited to identification of strains that are difficult to identify by phenotypic methods. In this study, using conventional full-sequence 16S rRNA gene sequencing as the "gold standard," we evaluated the usefulness of the MicroSeq 500 16S ribosomal DNA (rDNA)-based bacterial identification system, which involves amplification and sequencing of the first 527-bp fragment of the 16S rRNA genes of bacterial strains and analysis of the sequences using the database of the system, for identification of clinically significant bacterial isolates with ambiguous biochemical profiles. Among 37 clinically significant bacterial strains that showed ambiguous biochemical profiles, representing 37 nonduplicating aerobic gram-positive and gram-negative, anaerobic, and Mycobacterium species, the MicroSeq 500 16S rDNA-based bacterial identification system was successful in identifying 30 (81.1%) of them. Five (13.5%) isolates were misidentified at the genus level (Granulicatella adiacens was misidentified as Abiotrophia defectiva, Helcococcus kunzii was misidentified as Clostridium hastiforme, Olsenella uli was misidentified as Atopobium rimae, Leptotrichia buccalis was misidentified as Fusobacterium mortiferum, and Bergeyella zoohelcum was misidentified as Rimerella anatipestifer), and two (5.4%) were misidentified at the species level (Actinomyces odontolyticus was misidentified as Actinomyces meyeri and Arcobacter cryaerophilus was misidentified as Arcobacter butzleri). When the same 527-bp DNA sequences of these seven isolates were compared to the known 16S rRNA gene sequences in the GenBank, five yielded the correct identity, with good discrimination between the best and second best match sequences, meaning that the reason for misidentification in these five isolates was due to a lack of the 16S rRNA gene sequences of these bacteria in the database of the MicroSeq 500 16S rDNA-based bacterial identification system. In conclusion, the MicroSeq 500 16S rDNA-based bacterial identification system is useful for identification of most clinically important bacterial strains with ambiguous biochemical profiles, but the database of the MicroSeq 500 16S rDNA-based bacterial identification system has to be expanded in order to encompass the rarely encountered bacterial species and achieve better accuracy in bacterial identification.

Bacteria↗

PubMed2004

Newly isolated bacterial strains belonging to Bacillaceae (Bacillus sp.) and Micrococcaceae accelerate death of the honey bee mite, Varroa destructor (V. jacobsoni), in laboratory assays.

Newly isolated bacterial strains belonging to Bacillaceae (Bacillus sp.), Micrococcaceae and three unidentified strains were tested for their pathogenicity against the mite, Varroa destructor. The Bacillus sp. strain and two of the strains belonging to the Micrococcaceae family significantly decreased the time for 50% mortality of the mite population (up to 57%) and hence may be potential control agents. In in vitro bioassay whole cells, extracellular broth and cellular extract of the Bacillus sp. strain effectively killed the mites, suggesting that both endotoxins and exotoxins contributed to the killing.

Animals↗

PubMed1990

In vitro activity of PD127,391, a new quinolone against bacterial isolates from cancer patients.

The in vitro activity of PD127,391, a new 4-quinolone, was compared to that of ciprofloxacin against common clinical bacterial isolates from patients with cancer. PD127,391 was found to have a broad antimicrobial spectrum with excellent activity against gram-positive isolates (including multidrug-resistant organism such as Corynebacterium jeikeium, Enterococcus faecalis, Enterococcus faecium, methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp.). It was also extremely active against gram-negative bacilli including Pseudomonas aeruginosa. Against organisms such as Achromobacter xylosoxidans, Acinetobacter spp. and Xanthomonas maltophilia, which are frequently resistant to a variety of antimicrobial agents, PD127,391 exhibited good activity, inhibiting all such isolates at a concentration of 0.5 micrograms/ml. Overall, PD127,391 was far more potent than ciprofloxacin against gram-positive isolates and slightly more active against gram-negative isolates. No bacterium that we examined needed more than 2 micrograms/ml of PD127,391 for inhibition.

Anti-Infective Agents↗

PubMed1994

[In vitro antibacterial activities of broad spectrum quinolones against clinical bacterial isolates].

In vitro activities of broad-spectrum quinolones (sparfloxacin (SPFX), ciprofloxacin (CPFX), lomefloxacin (LFLX), fleroxacin (FLRX), and levofloxacin (LVFX) were examined against clinical bacterial isolates: Klebsiella pneumoniae, Haemophilus influenzae, Moraxella subgenus Branhamella catarrhalis, Methicillin-sensitive Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Enterococcus faecium, and Streptococcus pneumoniae). Antibacterial activities of SPFX, CPFX, and LVFX against Gram-negative bacteria such as K. pneumoniae, M. (B) catarrhalis and H. influenzae were better than those of FLRX and LFLX. SPFX showed the highest activity against all Gram-positive bacteria tested in this study. However, strains showed high MIC (> or = 16 micrograms/ml) to SPFX were found among MRSA, E. faecalis, and E. faecium, whose isolation frequencies were 28.6%, 10.0%, and 6.7%, respectively. The results of this study suggest that resistant strains of Gram-positive bacteria against new quinolone might increase among clinical isolates.

4-Quinolones↗

PubMedDate not supplied

Antimicrobial agent resistance in bacterial isolates from patients with diarrhea and urinary tract infection in the Sudan.

Antimicrobial sensitivity tests were performed on four-hundred and ninety-seven bacterial isolates from Sudanese patients with diarrhea or urinary tract infections. Shigella dysenteriae type I and enteropathogenic Escherichia coli showed high resistance rates (percentage of isolates showing antibiotic resistance) against the commonly-used antimicrobial agents: ampicillin, amoxicillin, chloramphenicol, tetracycline, cotrimoxazole, nalidixic acid, sulfonamide, and neomycin, and were completely sensitive to ciprofloxacin. Eighteen resistance patterns against nine antimicrobial agents tested were observed in enteric pathogens. Resistance to ampicillin, amoxicillin, tetracycline, cotrimoxazole, and sulfonamide was the most frequent pattern. The common urinary pathogens, E. coli, Klebsiella pneumoniae, and Proteus mirabilis showed high rates of resistance to ampicillin, amoxicillin, cotrimoxazole, tetracycline, sulfonamide, trimethoprim, streptomycin, and carbenicillin. We recommend that physicians seek updated knowledge of the common antibiotic-sensitivity patterns when starting empirical antibiotic therapy in Sudanese patients with diarrhea or urinary tract infection.

Anti-Bacterial Agents↗

PubMed2004

Comparison of the API 20E and BBL Crystal E/NF identification systems for differentiating bacterial isolates from apparently healthy reared sea bass (Dicentrarchus labrax).

The ability of two commercial rapid identification systems, API 20E and BBL Crystal E/NF, to reliably identify bacterial isolates from the internal organs of reared sea bass were compared. The tests gave different results: API 20E identified bacteria as Pseudomonas spp. with 37% accuracy, while BBL Crystal E/NF identified them as Flavobacterium odoratum with 99% accuracy. Although F. odoratum is not a marine fish pathogen, conventional tests conducted with the same isolates were more indicative of them being Flavobacterium spp. than Pseudomonas spp., suggesting that BBL Crystal E/NF was more reliable in this identification. Both systems were found to be applicable for diagnostics of marine fish pathogens, but should be used with caution because of possible misinterpretation.

Animals↗

PubMed1976

Comparison of in vitro antimicrobial activity of cefamandole and cefazolin with cephalothin against over 8,000 clinical bacterial isolates.

Antimicrobial susceptibility to cefamandole versus cephalothin and cefazolin versus cephalothin was compared by the broth microdilution method against 3,000 and 5,895 clinical bacterial isolates, respectively. Cefamandole and, to a lesser degree, cefazolin showed greater activity than cephalothin against Enterobacteriaceae, but the three drugs were comparable against gram-positive cocci.

Bacteria↗

PubMed1986

Changes in Protein Composition of Three Bacterial Isolates from Marine Waters during Short Periods of Energy and Nutrient Deprivation.

Two-dimensional gel electrophoresis analysis of and total cell protein determination for three bacterial isolates from marine waters at the onset and after 24 h of energy and nutrient deprivation demonstrated that the three isolates exhibited different pathways of starvation survival. Two strains appeared to synthesize new proteins during starvation.

Journal Article↗

PubMedDate not supplied

[The most frequent bacterial isolates in biological samples from HIV-infected patients].

A descriptive and retrospective study was conducted aimed at knowing the behavior and the frequency of the bacterial isolations most frequently found in different biological samples (sputum, blood and urine) from patients with HIV/AIDS diagnosis that were seen at the Outpatient Department or that were admitted at the Hospital of "Pedro Kouri" Institute of Tropical Medicine from 1997 to 2001. It was observed that most of the isolations were obtained from sputum samples and that Pseudomonas aeuroginosa was the most isolated microorganism in all samples. Pseudomonas aeuroginosa proved to be the most isolated microorganism in sputum with 28.5%. The bacteria most commonly isolated in blood was Staphylococcus epidermidis with 48.5%. The uropathogenic microorganism most found in urine was Escherichia coli with 43.5%.

HIV Infections↗

PubMed1997

Immunochemical characterization of lipopolysaccharide from glucose-nonfermenting gram-negative clinical bacterial isolate.

A glucose-nonfermenting Gram-negative bacterial strain isolated from bronchofiberoscope used for examination of the patients suffering from pulmonary diseases was subjected to phenol-water extraction. Lipopolysaccharides (LPS) isolated from the water and the phenol phase differed in fatty acid composition. Both contained xylose, glucose, glucosamine and components typical for LPS, namely heptose, 3-deoxyoctulosonic acid (Kdo) and 3-hydroxymyristic acid. The presence of sphingosine in all LPS preparations classifies the strain to the genus Sphingomonas.

Animals↗

PubMed2001

[Effectiveness of the standard mode of chemotherapy for newly-diagnosed patients with destructive pulmonary tuberculosis with bacterial isolation].

The authors evaluated the efficiency of a routine drug therapy regimen by the WHO category 1 in treating 149 new cases of destructive pulmonary tuberculosis and bacterial isolation. They used not only the WHO sputum smear negativization criterion, but the data of cultural studies and on lung cavernous closure. The specific features of the approach applied were compulsory cultural studies determining Mycobacterium sensitivities before treatment and compulsory correction of chemotherapy after there was evidence for the sensitivity. Retrospective analysis of 6-month chemotherapy has ascertained that the efficiency of the routine drug therapy regimen largely depends on the baseline extent of infiltrative and destructive changes in the lung and on the baseline resistance of Mycobacteria tuberculosis. They showed a high baseline resistance to streptomycin (20.6%) and streptomycin and isoniazid (33.1%) and a low baseline resistance to ethambutol (5.1%). In these cases, the more optimum regimen was a combination of rifampicin, pyrazanamide, and ethambutol. When Mycobacteria showed multidrug resistance, the routine regimen was ineffective and caused amplification to a larger number of drugs. A modified treatment course using the routine regimen in the intensive phase was developed. If Mycobacterial resistance was present, compulsory correction was made by using reserve agents, pathogenetic treatments, artificial pneumothorax or surgical interventions, which made it possible to abacillate 94.1% of patients by their smears and culture by months 4-5 and to close caverns in 91.3% of cases by months 8-10.

Adolescent↗

PubMed1995

An in vitro comparison of the susceptibilities of bacterial isolates from patients with conjunctivitis and blepharitis to newer and established topical antibiotics.

This retrospective study compared new and established topical antibiotics with regard to the in vitro susceptibility of bacterial isolates recovered from patients with conjunctivitis (n = 385) and blepharitis (n = 173) using the National Committee for Clinical Laboratory Standards-approved disk diffusion method. The percent susceptibility of recovered isolates to single antibiotic agents or combinations were ranked from greatest to least: chloramphenicol, bacitracin/polymyxin B, ofloxacin, sulfa, ciprofloxacin, trimethoprim/polymyxin B, norfloxacin, gentamicin, bacitracin, trimethoprim, tobramycin, neomycin, erythromycin, and polymyxin B. We determined that none of the available topical antibiotics provided 100% broad spectrum coverage in vitro. Established antibiotics often provided coverage comparable to the newer drugs. Due to the unproven value of in vitro testing as a predictor of clinical outcome in bacterial blepharitis and conjunctivitis, the ophthalmologist should choose therapy based on clinical experience, ongoing critical evaluation of available antibiotics, and cost-effectiveness.

Administration, Topical↗