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PubMed2005

Prevalence and associations between bacterial isolates from dry mammary glands of dairy cows.

To assess the prevalence and patterns of bacterial isolates, cultures were made from the dry mammary glands of dairy cows in six commercial dairy herds in the UK. Milk samples were taken from all four quarters of 480 cows at drying off and at weekly intervals from 14 days before to seven days after calving. A major mastitis pathogen was isolated from at least one quarter of 220 (45.8 per cent) of the cows and from more than one quarter of 90 (18.8 per cent) of them. During the late dry to calving period, of the 957 quarters with three culture results, a major mastitis pathogen was cultured from 236 (24.7 per cent) quarters of 186 (38.8 [corrected] per cent) cows. The most commonly isolated major pathogen was Escherichia coli, followed by Streptococcus uberis and coagulase-positive staphylococci. There were significant differences between the patterns of isolates from different farms and in different calving months, suggesting that the rate of infection was partially dependent on external conditions. The isolation of E. coli, S. uberis or coagulase-positive staphylococci from a cow during the late dry/periparturient period was associated with an increased risk of that cow being culled in the next lactation. Bayesian general linear mixed models were used to assess the associations between the different bacterial species. The probability of isolating either E. coli or S. uberis was significantly greater when the other organism was cultured in a milk sample; this was also true of coagulase-positive staphylococci and S. uberis. When Corynebacterium species were isolated from a milk sample, the probability of isolating coagulase-positive staphylococci or S. uberis decreased significantly, and when coagulase-negative staphylococci were isolated the probability of isolating coagulase-positive staphylococci was reduced.

Animals↗

PubMed2005

Characterization of floating activity of indigenous diesel-assimilating bacterial isolates.

Six diesel-degrading bacterial strains were isolated from oil-polluted sites located in central Taiwan. The floating activity of the isolates in an oil-supplemented liquid medium was monitored. Cell-surface hydrophobicity as well as cell-free and cell-residue emulsification activities were also investigated. Three isolates, identified as Gordonia alkanivorans CC-JG 39, Rhodococcus erythropolis CC-BC 04, and R. erythropolis CC-BC 11, were found to float and grow near the diesel layer on the surface. The other three isolates (namely, Comamonas testosteroni CC-CF3, Acinetobacter sp. CC-CF 5, and Sphingomonas yanoikuyae CC-CG 22) did not display floating activity, as they distributed uniformly in the liquid medium. Isolated cell walls of the floating strains appeared to settle at a lower sucrose density than the non-floating strains. The floating strains were also characterized by a higher cell-surface hydrophobicity and a higher cell-residue emulsification activity than the non-floating strains. In fact, the floating strains were thought to produce extracellular emulsifiers due to their higher supernatant emulsification activity than the non-floating strains. The floating activity of G. alkanivorans CC-JG 39 may be associated with the production of extracellular polymeric substances that formed an "air-bag" structure facilitating cell floating. The floating ability may also correlate with a high cellular hydrophobicity arising from unique cell wall compositions or cell-wall-bound surface active products.

Bacteria↗

PubMed1973

Survival of bacterial isolates exposed to simulated Jovian trapped radiation belt electrons and solar wind protons.

With missions to Jupiter, the spacecraft will be exposed for extended durations to solar wind radiation and the Jovian trapped radiation belt. This study is designed to determine the effect of these radiation environments on spacecraft bacterial isolates. The information can be used in the probability of contamination analysis for these missions. A bacterial subpopulation from Mariner Mars 1971 spacecraft (nine spore-forming and three non-spore-forming isolates) plus two comparative organisms, Staphylococcus epidermidis ATCC 17917 and a strain of Bacillus subtilis var. niger, were exposed to 2, 12, and 25 MeV electrons at different doses with simultaneous exposure to a vacuum of 1.3 x 10(-4) N m-2 at 20 and -20 degrees C. The radioresistance of the subpopulation was dependent on the isolate, dose and energy of electrons. Temperature affected the radioresistance of only the spore-forming isolates. Survival data indicated that spores were reduced approximately 1 log/1500 J kg-1 (10 J kg-1=1 krad), while non-spore-forming isolates (micrococci) were reduced 1.5-2 logs/1500 J kg-1 with the exception of an apparent radioresistant isolate whose resistance approached that of the spores. The subpopulation was found to be less resistant to lower energy than to higher energy electrons. The bacterial isolates were exposed to 3 keV protons under the same conditions as the electrons with a total fluence of 1.5 x 10(13) p cm-2 and a dose rate of 8.6 x 10(9) p cm-2 s-1. The results showed that only 20% of S. epidermidis and 45% of B. subtilis populations survived exposure to the 3 keV protons, while the mean survival of the spacecraft subpopulation was 45% with a range from 31.8% (non-spore-former) to 64.8% (non-spore-former). No significant difference existed between spore-forming and non-spore-forming isolates.

Bacillus subtilis↗

PubMed1985

Bacterial isolates from tracheobronchial aspirates of healthy horses.

Of tracheobronchial aspirates from 50 clinically healthy Thoroughbred racehorses, 4 (8%) had aerobic bacteria with recognized pathogenicity, 12 (24%) contained transient bacterial isolates, and 37 (74%) had no bacterial growth. Of tracheobronchial aspirates from 36 pastured, nonracing racehorses, 3 (8%) had bacteria with recognized pathogenicity, 23 (64%) contained transient bacteria, and 10 (28%) had no bacterial growth. Anaerobes were not isolated from 12 of 12 pastured horses. Transient bacteria were isolated more often in the pastured horses.

Animals↗

PubMed1995

Typing of sequential bacterial isolates by pulsed-field gel electrophoresis.

We typed 39 sets of multiple bacterial isolates of the same species from patients by pulsed-field gel electrophoresis of genomic DNA (PFGE). Isolates were cultured from different sites or over a 2-week or longer interval. Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae were tested. Excluding E. cloacae, 28 of 32 sets of isolates (87%) demonstrated only identical or highly related PFGE types. Four of the seven sets of E. cloacae showed different types. For species other than E. cloacae, our results suggest that patients are usually colonized and infected with a single strain of these bacterial pathogens. Unlike all of the other tested species, E. cloacae PFGE typing differences suggested the presence of multiple strains causing colonization and infection.

Bacteria↗

PubMed1986

In vitro activity of carumonam (RO 17-2301), BMY-28142, aztreonam, and ceftazidime against 7,620 consecutive clinical bacterial isolates.

For 45-60 days four geographically separate clinical laboratories tested routine clinical bacterial isolates for susceptibility to carumonam, aztreonam, BMY-28142, and ceftazidime by the broth microdilution method. All four drugs were highly active against Enterobacteriaceae, inhibiting greater than 96% of the 4887 strains tested at less than or equal to 8.0 microgram/ml. The minimal inhibitory concentration at which 50% of the isolates were inhibited for each drug was less than or equal to 0.125 micrograms/ml. Ceftazidime was the most active against nonenteric gram-negative bacilli (86% inhibited at less than or equal to 8.0 micrograms/ml), followed by BMY 28142 (82%), carumonam (75%), and aztreonam (68%). The two monobactams exhibited no activity against gram-positive cocci at the concentrations tested, whereas BMY-28142 had excellent activity against nonenterococcal streptococci and good activity against staphylococci.

Anti-Bacterial Agents↗

PubMed1999

Growth Rates of Marine Bacterial Isolates on Particulate Organic Substrates Solubilized by Freely Released Extracellular Enzymes.

> Abstract Growth rates of marine bacterial isolates on particulate organic substrates were measured using a novel apparatus which restricts bacterial cells to the uptake of hydrolysate produced from particulate substrates only by enzymes that are actively released from the bacterium into the culture medium. Significant, varying growth rates were measured for four different marine bacteria, using three different, ecologically significant particulate organic substrates (preparations of amylopectin, chitin, and animal hide). Growth rates sometimes approached but were usually lower than rates that have been reported in laboratory experiments using dissolved organic growth substrates. These results are consistent with recent model predictions and have important implications for microbial ecology and material cycling in diverse liquid-bathed environments.

Journal Article↗

PubMed1980

Screening of bacterial isolates for mannose-specific lectin activity by agglutination of yeasts.

A total of 393 clinical bacterial isolates were tested for their ability to agglutinate yeast cells of either Saccharomyces cerevisiae or Candida albicans. A positive agglutination of yeasts that could be prevented by methyl alpha-D-mannoside was taken as an indication for the possible presence of a mannose-specific lectin (carbohydrate-binding protein) on the surface of the tested bacteria. Agglutination tests on glass slides showed that 38% of all the isolates tested were positive in their capacity to agglutinate yeasts. Among the various strains tested, all isolates of Serratia marcescens, Proteus morganii, and Citrobacter diversus, as well as 94% of Klebsiella pneumoniae, were positive. On the other hand, only 46% of the Escherichia coli, 48% of the salmonellae, 44% of the Citrobacter freundii, and 71% of the Aeromonas hydrophila isolates were positive. A quantitative determination of the lectin activity done by observing the agglutination of yeasts in microtiter plates showed that S. marcescens isolates were the most avid binders to the yeast, whereas Klebsiella and Citrobacter isolates were the weakest.

Agglutination↗

PubMed1986

Comparative "in vitro" activity of ciprofloxacin (Bay o9867) and other antimicrobial agents against urinary bacterial isolates.

Ciprofloxacin (Bay o9867) is a new quinolone derivative. Its activity against 537 urinary bacterial isolates was compared with those of ampicillin, amikacin, carbenicillin, cefazolin, cefotaxime, cefoxitin, ceftazidime, nalidixic and oxolinic acids, norfloxacin, trimethoprim, and other antimicrobial agents, when appropriate. It inhibited 90% of Citrobacter freundii, Enterobacter spp., E. coli, Klebsiella spp., Proteus spp., and Serratia spp. at 0.78 microgram/ml. The majority of Pseudomonas aeruginosa, including gentamicin-resistant strains, was inhibited by 0.78 microgram/ml. The minimal inhibitory concentrations of ciprofloxacin for 90% of Staphylococcus aureus, including methicillin-resistant strains, and Streptococcus faecalis were 0.78 microgram/ml and 1.56 micrograms/ml respectively. Ciprofloxacin inhibited organisms resistant to ampicillin, carbenicillin, cefazolin, nalidixic and oxolinic acids, and trimethoprim. Ciprofloxacin was less active in urine at pH 5.8 than in broth, but serum did not decrease minimal inhibitory concentrations or minimal bactericidal concentrations. There was no major difference between minimal inhibitory concentrations and minimal bactericidal concentrations. Spontaneous rates of mutation to resistance of representative urinary bacteria were studied. For ciprofloxacin these rates ranged from 8.2 X 10(-9) to 1.5 X 10(-11).

Anti-Bacterial Agents↗

PubMed2005

Degradation and metabolism of hexazinone by two isolated bacterial strains from soil.

Two hexazinone-degrading bacterial strains were isolated from soil by enrichment culture technique, and identified as Pseudomonas sp. and Enterobacter cloacap. The two purified isolates, designated as WFX-1 and WFX-2, could rapidly degrade hexazinone with a half-life of 3.08 days and 2.95 days in mineral salt medium (MSM), while their mixed bacterial culture was found to degrade hexazinone, at an initial concentration of 50 microg/ml, by enhancing 2.3-fold over that when the isolates were used alone. Two microbial metabolites (A and D) were obtained by preparative TLC and identified on the basis of the spectral data of IR, 1H NMR and HPLC-ESI-MS, but both of them were known products as they had been reported in soil and vegetation metabolites of hexazinone. However, metabolites B and C were new degradates, whose molecular weights (MW) were 157 and 156, respectively, being reported from microbial metabolism for the first time.

Enterobacter↗

PubMed1999

In vitro activity of trovafloxacin against ciprofloxacin-susceptible and -resistant clinical bacterial isolates and assessment of the trovafloxacin disk test.

A total of 4241 consecutive clinical bacterial isolates from 10 North American medical centers were tested for susceptibility to trovafloxacin. Trovafloxacin was significantly more active than ciprofloxacin against Gram-positive bacteria, Acinetobacter spp., and Stenotrophomonas maltophilia, and resistance to trovafloxacin occurred in these groups only among isolates with high-level resistance (MIC > or = 16 micrograms/mL) to ciprofloxacin. With other species, the two drugs had comparable activity. Concerns about staphylococci and Pseudomonas aeruginosa with trovafloxacin MICs of 2.0 micrograms/mL (the upper end of the susceptible category) are discussed. Results of trovafloxacin disk diffusion test on more than 3200 nonfastidious isolates supported the FDA-approved zone size interpretive criteria when the MIC breakpoint of < or = 2.0 micrograms/mL is used to define the trovafloxacin-susceptible category.

Anti-Infective Agents↗

PubMed2004

Aerobic bacterial isolates from burn wound infections and their antibiograms--a five-year study.

A retrospective study of major aerobic bacterial isolates from pus/wound swabs taken from patients admitted to the burn unit at Govt. Medical College Hospital, Chandigarh, India, over a period of 5 years (June 1997-May 2002) was undertaken. The study was carried out to determine the bacterial profile and antimicrobial susceptibility of the isolates and to describe the change in trends over the study period. The pus/wound swabs yielded very high culture positivity (96%) for 665 total isolates. Pseudomonas aeruginosa was found to be most common isolate (59%) followed by Staphylococcus aureus (17.9%), Acinetobacter spp. (7.2%), Klebsiella spp. (3.9%), Enterobacter spp. (3.9%), Proteus spp. (3.3%) and others (4.8%). Although P. aeruginosa continued to remain the predominant isolate over the five years, a constant and significant increase in the incidence of Acinetobacter spp. was found. Amikacin was found to be the most effective drug against gram negative bacteria, however, resistance to it was significantly increased over 5 years. For S. aureus and P. aeruginosa netilmicin and piperacillin were found to be the most effective drugs. Most of the isolates showed high level resistance to antimicrobial agents.

Bacteria, Aerobic↗

PubMed1995

[Susceptibility of bacterial isolates from the equine respiratory tract to trimethoprim, sulfadoxine, sulfadimethoxine and combinations of these compounds].

Using a broth microdilution technique, the in vitro susceptibility of bacterial isolates from the equine respiratory tract to trimethoprim, sulfadoxine, sulfadimethoxine, and combinations of these compounds was determined. The bacterial strains (n = 88) isolated recently from horses with respiratory symptoms belonged to the following species: Streptococcus equi subsp. zooepidemicus (n = 34), Streptococcus equi subsp. equi (n = 22), Staphylococcus aureus (n = 9), Klebsiella pneumoniae (n = 7), Rhodococcus equi (n = 4), Pseudomonas spp. (n = 3) and Escherichia coli (n = 3). In addition, two isolates of Enterobacter spp. and one isolate of Streptococcus equisimilis, Staphylococcus intermedius, Proteus mirabilis and Serratia marcescens were examined. For determination of susceptibility of an organism the following minimal inhibitory concentrations (MIC) were fixed as limiting values: Trimethoprim < or = 0.5 microgram/ml, sulfadoxine < or = 32 micrograms/ml, sulfadimethoxine < or = 32 micrograms/ml, trimethoprim/sulfadoxine < or = 0.5/32 micrograms/ml, trimethoprim/sulfadimethoxine < or = 0.5/32 micrograms/ml. As expected, Rhodococcus-equi-isolates were resistant to the antimicrobials tested. However, most of the clinically more common isolates showed a high degree of susceptibility to the combinations. The fractional inhibitory concentration (FIC) indices indicated synergism of the combination-partners in a wide range. According to these in vitro results, application of trimethoprim/sulfonamide combinations for the initial therapy of equine respiratory tract infections can be recommended.

Animals↗

PubMed1995

[Survey bacterial isolates from blood samples during 1987-1993 in our department].

We analyzed the changes in frequency of bacterial isolates from the blood samples in our department from May 1987 to December 1993. 565 isolates from 4887 samples (11.6%) were detected. Among the detected microorganisms, the rate of gram-positivecocci (GPC) was much higher than the other kinds of the isolates each year. Especially, 80-90% of GPC were occupied by only 2 kinds of microorganisms, coagulase negative Staphylococci (CNS) and S. aureus. Among gram-negative-rods (GNR), constant increase of S. marcescens and transient increase of Enterobacter and P. aeruginosa were recognized. In 30 cases (5.3%), 2-3 kinds of microorganisms were isolated concomitantly, and in 55 cases (9.7%), the microorganisms, which was mainly caused by CNS, S. aureus and Candida, was isolated from both blood samples and the tip of the IVH catheter concomitantly. 42.5% of the bacterial positive cases in 1933 underwent 2 more kinds of the indwelling catheters and 48.3% were administrated antibiotics. Most of the cases had underlying diseases including mainly malignant tumor (leukemia, solid tumor), cerebrovascular diseases, and multiple injuries.

Bacteremia↗

PubMed2006

Biodegradation of hexazinone by two isolated bacterial strains (WFX-1 and WFX-2).

Two hexazinone-degrading bacterial strains were isolated from soil by enrichment culture technique, and identified as Pseudomonas sp. and Enterobacter cloacap, respectively. The two purified isolates, designated as WFX-1 and WFX-2, could rapidly degrade hexazinone with half-lives of 3.08 and 2.95 days in mineral salts medium (hereafter referred to as MSM). In contrast, their mixed bacterial culture (herein abbreviated as MBC) was found to degrade hexazinone, at an initial concentration of 50 mg l(-1), by enhancing 2.3-fold over that when the isolates were used alone. The degradation of hexazinone by MBC in MSM clearly decreased concomitant with the increase of initial concentration, and the level of hexazinone that was toxic enough to totally inhibit degradation was in the range of 150-200 mg l(-1). The appropriately combined conditions for hexazinone degradation by MBC in MSM were studied, and found to be pH 5.5, 30 degrees C and at agitation of 120 rpm. The addition of MBC to soil had a greater impact on disappearance of hexazinone, which nearly increased fivefold over that of the control set. As a result, findings in the present investigation provide useful information for soil and water decontamination of hexazinone.

Biodegradation, Environmental↗

PubMed1982

The in vitro activity of moxalactam against 430 clinical, bacterial isolates.

The in vitro activity of the novel beta-lactam antibiotic moxalactam against 430 bacterial isolates was determined by an agar dilution method. Moxalactam was highly active against Enterobacteriaceae including indole-positive Proteus and Providencia, all isolates being susceptible to 1.0 microgram/ml or less. The drug was somewhat less active against Gram-positive cocci and Pseudomonas aeruginosa, and enterococci were highly resistant. All Haemophilus influenzae isolates were inhibited by 0.06 microgram/ml or less. Activity against Bacteroides fragilis was good but wide variations of minimal inhibitory concentrations were noted. Moxalactam may become a useful alternative to the aminoglycosides in the treatment of serious infections caused by Gram-negative bacteria.

Anti-Bacterial Agents↗

PubMed1980

The in vitro activity of cefamandole against 3312 bacterial isolates. A Norwegian multicentre study.

In a multicentre study the in vitro activity of cefamandole against 3312 bacterial isolates was compared to the antibacterial activity of cephalothin, ampicillin, oxacillin, doxycycline and tobramycin. Cefamandole and tobramycin showed the highest activity against the Enterobacteriaceae isolates, whereas the Staphylococcus aureus isolates were slightly less sensitive to cefamandole than to cephalothin and oxacillin. There was no significant difference between the activity of cephalothin and cefamandole against the isolates of Haemophilus influenzae and enterococci.

Anti-Bacterial Agents↗

PubMed2003

In vitro susceptibility of 4903 bacterial isolates to gemifloxacin--an advanced fluoroquinolone.

The in vitro activity of gemifloxacin against over 4900 bacterial isolates was determined by microbroth dilution with interpretation in accordance with NCCLS guidelines. Susceptibility results were compared with those for ciprofloxacin, gatifloxacin, levofloxacin and moxifloxacin. Gemifloxacin and the other fluoroquinolones were not affected by either beta-lactamase production or penicillin-resistance in Streptococcus pneumoniae. The MIC90 values for gemifloxacin were: S. pneumoniae 0.063 mg/l; Haemophilus influenzae 0.016 mg/l; Moraxella catarrhalis 0.008 mg/l, methicillin-susceptible Staphylococcus aureus 0.063 mg/l; methicillin-susceptible Streptococcus pyogenes 0.031 mg/l; Enterobacteriaceae 0.031-0.16 mg/l; Pseudomonas aeruginosa 4 mg/l; Neisseria meningitidis 0.008 mg/l. The MIC90 for gemifloxacin was lower than those for the other quinolones tested against S. pneumoniae (ciprofloxacin 2-4 mg/l, gatifloxacin 0.5 mg/l, levofloxacin 1-2 mg/l, moxifloxacin 0.25 mg/l). This study confirms the enhanced potent activity of gemifloxacin against Gram-positive pathogens, its broad-spectrum, Gram-negative activity and indicates that gemifloxacin is likely to have an important role in treating patients with Gram-positive and/or Gram-negative infections.

Anti-Infective Agents↗