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PubMed1995

The influence of antibiotics and antitumor agents on the relaxation activity of Pisum sativum leaf chloroplast topoisomerase I.

DNA topoisomerase was isolated from pea leaf chloroplasts. The relaxation activity of this topoisomerase was Mg2+ dependent and sensitive to ethidium bromide and novobiocin, a gyrase inhibitor. Chloroplast topoisomerase (Topo I) was ATP independent, as shown by the characteristic gel distribution of topoisomers. Topoisomerase, compared with the known eucaryotic topoisomerase I, was not stimulated by polyamines as are spermidine, spermine, and cadaverine. Ethidium bromide, DAPI, heparin, nalidixic acid, and m-AMSA (but not camptothecin) were able to inhibit the relaxation activity of chloroplast topo I. Nalidixic acid, novobiocin, m-AMSA, camptothecin, and amiloride were tested for their effects on the topoisomerase-catalyzed "cleavage complex" between DNA and chloroplast DNA topoisomerase I.

Amiloride↗

PubMed2003

Evaluation of culture media for the recovery of Mycobacterium avium subsp. paratuberculosis from Cheddar cheese.

AIMS: The study evaluated the efficacy of four Mycobacterium avium subsp. paratuberculosis (MAP) culture media in suppressing commonly used starter cultures and typical nonstarter microflora present during the manufacture and ripening of Cheddar cheese, with a view to identify a suitable medium for the enumeration of MAP during laboratory-scale Cheddar production. METHODS AND RESULTS: Four Cheddar starter cultures and Cheddar cheese manufactured with these starters were inoculated onto Herrold's egg yolk medium (HEYM); HEYM supplemented with vancomycin, amphotericin B and nalidixic acid (HEYM/VAN); Middlebrook 7H10 agar containing polymyxin, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) antibiotic supplement; and BACTEC 12B radiometric medium with and without a preliminary decontamination step (0.75% w/v hexadecylpyridinium chloride (HPC), 5 h). The inclusion of a decontamination step inhibited all Cheddar cheese starter and nonstarter micro-organisms. The medium 7H10/PANTA and to a lesser extent HEYM/VAN were effective inhibitors of cheese microflora when no decontamination step was employed. CONCLUSIONS: Middlebrook 7H10 medium, supplemented with PANTA antibiotics, suppressed all micro-organisms associated with ripening Cheddar cheese manufactured with pasteurized milk. SIGNIFICANCE AND IMPACT OF THE STUDY: A MAP culture medium has been identified, which may be used to enumerate this bacterium during the laboratory manufacture and ripening of Cheddar cheese and hence facilitate further research into the persistence of this pathogen in the product.

Animals↗

PubMed1994

Lidocaine hydrochloride and acetylsalicylate kill bacteria by disrupting the bacterial membrane potential in different ways.

Lidocaine hydrochloride (LH), a local anesthetic, and acetylsalicylate (AcSAL), show antibacterial activity for both gram-negative and gram-positive bacteria. Kinetic studies indicated that antibacterial activity of LH was different from that of AcSAL. A subinhibitory concentration of LH and AcSAL enhanced the sensitivity of Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa to novobiocin and nalidixic acid. The synergistic effect of AcSAL with novobiocin and nalidixic acid was higher than that of LH. The effect of both drugs on the membrane potential of inner membrane was also studied using inverted membrane vesicles of bacteria. Both LH and AcSAL depolarized the membrane potential after the vesicles were energized with nicotinamide adenine dinucleotide. However, unlike AcSAL, pre-treatment of vesicles with LH had no effect on the generation of membrane potential. These results suggest that depolarization of the cytoplasmic membrane, preceded by the permeabilization of the outer membrane for gram-negative bacteria, is associated with antibacterial activity of LH and AcSAL. The difference in actions of LH and AcSAL was discussed.

Anti-Bacterial Agents↗

PubMed2006

Emergence of Vibrio cholerae O1 biotype El Tor serotype Inaba causing outbreaks of cholera in Orissa, India.

A total of 431 rectal swabs, collected from acute diarrheal cases at a surveillance site and at different diarrheal outbreak areas of Orissa from May to October 2005, were bacteriologically analyzed. Out of 265 culture-positive samples, Vibrio cholerae O1 was isolated in 56 samples (20.8%), of which 37 were the Inaba serotype and 19 were the Ogawa. The antibiogram profile revealed that all the V. cholerae O1 Ogawa and Inaba serotypes were uniformly sensitive to ampicillin, chloramphenicol, gentamicin, ciprofloxacin, norfloxacin and tetracycline. The V. cholerae O1 Inaba serotypes were resistant to furazolidone and nalidixic acid, while the Ogawa strains were resistant to furazolidone, nalidixic acid and neomycin. The multiplex polymerase chain reaction (PCR) assay on some selected strains of both serotypes revealed that all the strains were positive for ctxA and tcpA genes showing biotype El Tor. The present study revealed the emergence of V. cholerae O1 biotype El Tor serotype Inaba, which caused sporadic outbreaks of cholera in 2005. The outbreaks of diarrheal disorders in one geographical area of the state (in the Pattamundai area, Kendrapara district) in 2005 were due to V. cholerae O1 Ogawa, whereas the other outbreaks in other areas (Puri, Khurda and Dhenkanal districts) from August to October 2005 were due to V. cholerae O1 serotype Inaba. This is the first report that an emergence of V. cholerae O1 serotype Inaba caused sporadic outbreaks of cholera in different parts of Orissa. Switching over of V. cholerae O1 Ogawa strains to Inaba, causing diarrheal outbreaks in Orissa, needs close monitoring.

Cholera↗

PubMed1989

[Antibacterial activity of pefloxacin in the urine during the 7 days following a single 800 mg oral dose].

Antibacterial activity of pefloxacin was studied in the urine after a single 800 mg oral dose in ten healthy female volunteers. Urine was collected in 9 periods: 0-6 h, 6-12 h, 12-24 h, 24-28 h, 48-72 h, 72-96 h, 96-120 h, 120-144 h, 144-168 h. Pefloxacin concentrations were assayed in all samples by a microbiological method and by HPLC. Urine antibacterial activity was determined towards five bacterial strains isolated in urine: 2 E. Coli strains, one sensitive and the other resistant to nalidixic acid (Nal-A), 1 Klebsiella pneumoniae resistant to nalidixic acid (Nal-B), 1 Staphylococcus saprophyticus and 1 Streptococcus faecalis; MIC's of pefloxacin against these strains were respectively 0.015, 0.25, 1, 0.50 and 2 micrograms/ml. Pefloxacin mean concentrations as determined by the microbiological method were 91.8 +/- 11.9, 71.7 +/- 7, 44.5 +/- 4.3, 24.4 +/- 4 and 5.4 +/- 0.8 micrograms/ml in the five first urine samples; low levels were present in the urine until the 7th day in 8 volunteers. HPLC results completed the already known data concerning pefloxacin elimination and metabolism; unchanged pefloxacin was excreted at the highest concentration during the 6 first hours; then demethylpefloxacin was eliminated at higher levels than pefloxacin with a ratio of 2/1 after the 24th hour. These two compounds were detectable in the urine during 5 to 7 days; oxodemethylpefloxacin and N-oxyde-pefloxacin were present in lower amounts and during a shorter period.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1989

[Antibacterial activity of lomefloxacin in the urine during the 4 days following a single 400 mg oral dose].

Antibacterial activity of lomefloxacin was studied in the urine after single dose of 400 mg in ten healthy female volunteers. Urine was collected in 7 periods: 0-3 h, 3-6 h, 6-12 h, 12-24 h, 24-48 h, 48-72 h, 72-96 h. Lomefloxacin concentration were assayed in all samples by microbiological method. Urine antibacterial activity was determined towards five strains isolated in urine: 2 E. Coli strains one sensitive and the other resistant to nalidixic acid (Nal-A), 1 Klebsiella pneumoniae resistant to nalidixic acid (Nal-B), 1 Staphylococcus saprophyticus and 1 Streptococcus faecalis. MIC's of lomefloxacin against these strains were respectively 0.06, 0.50, 0.50, 0.25 and 4 micrograms/ml. Lomefloxacin mean concentrations were 208.5 +/- 44.2, 104.3 +/- 15.2, 100.5 +/- 17.9, 36.8 +/- 8.2, 9.6 +/- 2.2 micrograms/ml in the five first urine samples. Low levels were present in urine the 4th day. Mean urine elimination percentage was 62.2 +/- 4.2% for the four days, with extreme values from 91.2 to 41.8%. Urine bacteriostatic activity against enterobacteriacae was greater than or equal to 32 the first day reaching 8,192 for the Nal-S E. Coli, it was greater than or equal to 4 the second day. Against staphylococcus it was greater than or equal to 64 the first day, greater than or equal to 16 the second day. Against enterococcus it was greater than or equal to 4 the first day. Against the strains implicated in UTI a bacteriostatic activity was present during 2 days in all subjects.

4-Quinolones↗

PubMed1994

[Antibacterial activity of ciprofloxacin in the urine during four days after a single 500 mg and 750 mg oral dose].

Antibacterial activity of ciprofloxacin was studied in the urine after a single 500 mg and 750 mg oral dose in ten healthy female volunteers. Urine was collected, after each single oral dose, during seven time periods: 0-3 h, 3-6 h, 6-12 h, 12-24 h, 24-48 h, 48-72 h, 72-96 h. Ciprofloxacin concentrations were assayed by microbiological method. Urine antibacterial activity was determined for five bacterial strains isolated in urine: 2 E. coli strains, one sensitive and the other resistant to nalidixic acid (Nal-A), 1 Klebsiella pneumoniae resistant to nalidixic acid (Nal-B), 1 Staphylococcus saprophyticus and 1 Enterococcus faecalis. MICs of ciprofloxacin against these strains were respectively 0.003, 0.06, 0.25, 0.06 and 0.5 micrograms/ml. Ciprofloxacin mean concentrations in the seven urine samples were 292.5 +/- 55.8, 81.1 +/- 16.9, 43.7 +/- 11.6, 11.5 +/- 1.9, 1.3 +/- 0.2, 0.3 +/- 0.05 et 0.1 +/- 0.05 micrograms/ml after a single 500 mg oral dose and 215.1 +/- 68.1, 56.1 +/- 17.8, 43 +/- 8.8, 14.4 +/- 5.5, 1.4 +/- 0.2, 0.4 +/- 0.1 and 0.2 +/- 0.05 micrograms/ml after a single 750 mg oral dose. Urine bacteriostatic activity was not very different after a 500 mg dose and a 750 mg dose. Against enterobacteriacae, after a 500 mg dose it was > or = 16 the first day; it was > or = 512 for the Nal-S E. coli. It was > or = 64 the first day, and remained between 2 and 32 the second day for the Nal-R strains (E. coli and Klebsiella).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1977

Fosfomycin and plasmidic resistance.

60 fosfomycin-resistant strains of gram-negative bacilli are submitted to conjugation experiments using as recipient cell E. coli K12 which is nalidixic acid resistant. After mating, the number of fosfomycin-resistant E. coli K2 colonies growing on selection plates containing nalidixic acid and fosfomycin never surpassed the normal rate of mutation for fosfomycin-resistance of the recipient strain. In 65% of the experiments, plasmidic resistance to other antimicrobials was transferred to E. coli K12, but was never accompanied by demonstrable fosfomycin resistance. High rate of normal mutation of recipient strain is signaled as the main problem for detecting the plasmidic nature of fosfomycin resistance. With our criteria regarding this fact we have been unable to confirm the plasmidic nature of fosfomycin resistance.

Acinetobacter↗

PubMed1984

The antimicrobial spectrum of norfloxacin.

The gamma-pyridone beta-carboxylic acids or 'quinolones' rival beta-lactam antibiotics in diversity of chemical structure and properties. Norfloxacin has a much wider spectrum than nalidixic acid which includes pseudomonas and Gram-positive cocci. It is also much more potent with MIC50 for Enterobacteriaceae of less than 0.06 mg/l. This high activity is reduced in the presence of urine--possibly due to pH, but probably not to clinically inadequate levels. The results of laboratory tests from around the world are reviewed; despite various techniques these are remarkably consistent. The wide spectrum of norfloxacin should make it useful for therapy of urinary tract infection, and for gut decontamination and enteric infections. The high potency should allow use of lower doses with possibly less toxicity than nalidixic acid.

Anti-Infective Agents, Urinary↗

PubMed1997

Susceptibility of Pseudomonas aeruginosa of various pyocin types to the newly synthesized ampicillin derivative, N-(6,7-difluoroquinolonyl)ampicillin.

Six hundred and thirty-two isolates of Pseudomonas aeruginosa of 17 pyocin types were collected in 1993 in Taiwan. Types 1, 10, 3, 35 and 12 were the most common pyocin types identified in Taiwan with isolation frequencies of 47.3%, 24.4%, 7.6%, 3.6% and 2.2%, respectively. Several pyocin subtypes were determined. All pyocin types (one isolate of each tested) were resistant to ampicillin and nalidixic acid, but sensitive to fluoroquinolone antibiotics, such as norfloxacin and enoxacin, indicating that cross-resistance to quinolone antibiotics of nalidixic acid and fluoroquinolone derivatives has not developed. A new ampicillin derivative of 6,7-difluoroquinolonic acid, N-(6,7-difluoroquinolonyl)-ampicillin (AU-1), was synthesized by coupling ampicillin with 6,7-difluoroquinolonic acid (FP-3). Compound AU-1 was much more active than either ampicillin or FP-3 alone against all pyocin types of P. aeruginosa and induced filamentation in most growing cells.

Ampicillin↗

PubMed1991

Development of resistance to quinolones in five patients with campylobacteriosis treated with norfloxacin or ciprofloxacin.

Development of resistance to nalidixic acid, norfloxacin and ciprofloxacin was observed in five patients with Campylobacter jejuni or Campylobacter coli infection. From all these patients nalidixic acid- and quinolone-susceptible strains were isolated initially, whereas after therapy with norfloxacin or ciprofloxacin strains resistant to these antibiotics were found. Campylobacter strains from the same patient always belonged to the same species and, with the exception of one case, showed identical rRNA gene restriction (rDNA) patterns. This indicates that double-infection with a susceptible and a resistant strain was not responsible for the phenomenon but rather that the infecting strain rapidly developed resistance following treatment.

Adult↗

PubMed2004

[E. coli: resistance to quinolones and beta-lactams of clinical strains isolated in the Franche-Comté region of France].

AIM OF THE STUDY: Numerous European studies have reported an increase of resistance to quinolones among E. coli. We conducted a regional study to update our knowledge on this evolution. MATERIALS AND METHODS: We evaluated the resistance phenotype and genotype of 115 clinical strains of E. coli. We collected data on individual treatment with fluoroquinolones, and the evolution of the use of these antimicrobial agents. RESULTS: Resistance to nalidixic acid and ciprofloxacin was 13.0 and 6.9, respectively. The frequency of resistance increased from 1999 to 2001, from 7.5% to 13.0% for nalidixic acid and from 5.4% to 6.9% for fluoroquinolones. Resistance to quinolones was significantly associated to beta-lactams resistance and was slightly higher for nosocomial isolates compared to community-acquired isolates. Previous treatment with fluoroquinolones was the major risk factor associated to E. coli resistance. From 1997 to 2001, fluoroquinolones use has increased in our hospital and particularly in the community. Analysis of molecular epidemiology shows a large clonal diversity among E. coli isolates. CONCLUSION: This study confirms the evolution through resistance to quinolones of E. coli isolates. This observation is not due to dissemination of resistant clonal strains and the selective pressure exerted by fluoroquinolones influences this evolution. Therapeutic alternatives, surveillance, and restriction of fluoroquinolones use are needed to control this spread of resistance.

Adult↗

PubMedDate not supplied

[Mutations of gyrA in ciprofloxacin resistant Escherichia coli strains].

In this study, the relationship between gyrA mutations and ciprofloxacin minimum inhibitory concentration (MIC) values was investigated in Escherichia coli strains. For this purpose, ciprofloxacin MIC values of 46 E. coli strains, isolated from out-patients and hospitalized patients, were determined by the agar dilution method. The "Quinolone Resistance Determining Region" (QRDR) of gyrA gene was amplified and restricted by Hinf-I enzyme. Ser-83 mutation was observed in all strains that have ciprofloxacin MIC values of 0.062 mg/L and higher. Afterwards, eight strains, that were found susceptible (MIC < 1 mg/L, n: 1), intermediate (MIC: 1-4 mg/L, n: 1) and high level resistant (MIC > 4 mg/L, n: 6) to ciprofloxacin, were chosen and mutations in QRDRs of these strains investigated by DNA sequence analysis. Ser 83 Leu mutation was found in all the chosen strains and Asp 87 Tyr or Asp 87 Asn mutations were also observed except the ciprofloxacin susceptible (MIC: 0.062 mg/L) one. In addition, base substitutions that don't lead to aminoacid changes were detected. The strain in which only Ser 83 Leu mutation was observed, showed high level nalidixic acid resistance (MIC > 256 mg/L). This fact was in favour of that, one mutation is enough to develop high level resistance to nalidixic acid. It was concluded that high level ciprofloxacin resistance requires at least two mutations in the QRDR of gyrA gene.

Anti-Infective Agents↗

PubMed2002

Drug sensitivity pattern of cholera in children.

OBJECTIVE: To study the drug sensitivity pattern of cholera in children. SETTING: DTU of Civil Hospital, Karachi. PATIENTS AND METHODS: All children age 2 months to 15 years attending Diarrhoea Treatment Unit (DTU) with acute onset of diarrhoea and dehydration were screened for cholera. Stool samples were collected in alkaline peptone and those positive for cholera had their antibiotic sensitivity determined. RESULTS: Of 846 stool specimens, 161 were positive for V. Cholera. All were sensitive to third generation cephalosporins and quinolones, 98-100% to nalidixic acid, 82-86% to chloramphenicol and 67-75% to doxycycline and all were resistant to cotrimaxazole. CONCLUSION: Cholera can be treated with nalidixic acid or chloramphenical in young children while doxycycline for older children. Cotrimoxazole is not effective. Efforts should be done for identification and surveillance of cholera cases, along with change of sensitivity pattern of Vibrio cholera.

Adolescent↗

PubMed1987

Antibacterial activity of the metabolites of ciprofloxacin and its significance in the bioassay.

The antibacterial activity of the metabolites of ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3- quinolinecarboxylic acid, Bay o 9867; designated tradename: Ciprobay) M1, M2, M3 and M4 was tested with the agar dilution method against various Gram-positive and Gram-negative bacteria in comparison to ciprofloxacin, norfloxacin and nalidixic acid. The results show that M1 had only a weak antibacterial activity comparable to nalidixic acid, whereas M2 was significantly less active. M3, which is one of the main metabolites in urine has a broad antibacterial activity but was less active than ciprofloxacin or norfloxacin. M4 which is a very minor metabolite of ciprofloxacin was the most active compound with minimal inhibitory concentrations for strains of Escherichia coli or Klebsiella pneumoniae in the range of norfloxacin, whereas with staphylococci the antibacterial activity was comparable to ciprofloxacin. Possible interactions between ciprofloxacin and the metabolites in the bioassay system, using Escherichia coli (ICB 4004) were studied, to explain discrepancies between the microbiological assay and the HPLC-method reported in the literature. It could be demonstrated that under conditions where the concentration of ciprofloxacin exceeds or equals the concentration of the metabolites or mixtures of them no increase in the inhibition zones for ciprofloxacin could be observed, which would have led to false high values for ciprofloxacin in the bioassay system. From these data we conclude that the antibacterial activity of the metabolites in biological specimens, e.g. urine, does not influence the bioassay results.

Bacteria↗

PubMed1977

[Selective effect of propolis in the isolation of Listeria monocytogenes (author's transl)].

Propolis is a substance produced by honeybees. It is inhibitory to some bacteria species, mainly Gram-positive bacteria, but less inhibitory to Listeria monocytogenes (L.m) than to the other Gram-positive bacteria tested. In order to obtain selective growth of L.m. from contaminated samples, the effect of propolis in plating media and broths on various strains of bacteria was examined. Table I shows the effect of increasing concentrations of propolis in tryptose-agar (TA). L.m. tolerated higher concentrations of propolis than Streptococcus viridans and Staphylococcus aureus. L.m. grew well in tryptosebroth (TB) that contained 0.15 mg propolis pr. ml medium, while Streptococcus viridans and Streptococcus agalactiae were completely inhibited as seen in Table II. Table III shows that when serum was added to the agar, the inhibitory effect was reduced. It can also be seen that Gram-negative bacteria grew quite well on media that contained 0.19 mg propolis pr. ml. To reduce the growth of Gram-negative bacteria, nalidixic acid was added to the medium. Table IV illustrates growth of various species of bacteria in tryptosephosphatebroth (TFB) with or without propolis and nalidixic acid. Most of the strains tested were inhibited, but Pseudomonas aeruginosa and to some extent faecal streptococci were able to grow in the medium that contained the selective substances. As a conclusion it seems that propolis may be a valuable additive to a medium for the selective isolation of L.m.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Detection of "Staphylococcus aureau" protein A on selective culture media (author's transl)].

Production of protein A by 100 various animal strains and 106 human strains of Staphylococcus aureus has been detected by conditioned haemagglutination after growth on seven different culture media: agar medium at n degrees 2 and Columbia agar with and without nalidixic acid (10.8 micrograms/ml), Baird-Parker, Chapman and tellurite-glycine-agar media. Rate of protein A-producing strains is as high on nalidixic acid media as on the same media without antibiotic. Baird-Parker, Chapman and tellurite-glycine-agar media are not convenient for protein A detection.

Culture Media↗

PubMed2006

Characterization of antimicrobial-resistant Salmonella isolated from imported foods.

Two-hundred eight Salmonella isolates recovered from over 5,000 imported foods entering the United States in 2001 were tested for antimicrobial susceptibilities and further characterized for quinolone resistance mechanisms, integron carriage, and genetic relatedness. Salmonella Weltevreden (20%), Salmonella Newport (6%), Salmonella Lexington (5%), and Salmonella Thompson (4%) were the four most common serotypes recovered. Twenty-three (11%) isolates were resistant to at least one antimicrobial, and seven (3.4%) to three or more antimicrobials. Resistance was most often observed to tetracycline (9%), followed by sulfamethoxazole (5%), streptomycin (4%), nalidixic acid (3%), and trimethoprim/sulfamethoxazole (2%). One Salmonella Schwarzengrund isolate recovered from squid imported from Taiwan exhibited resistance to eight antimicrobials, including ampicillin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole. Six isolates (Salmonella Bareilly, Salmonella Derby, Salmonella Ohio and three Salmonella Schwarzengrund) contained class 1 integrons, which carried several resistance genes including dhfrI/dhfrXII, aadA, pse-1, and sat1, conferring resistance to trimethoprim/sulfamethoxazole, streptomycin, ampicillin, and streptothricin, respectively. Five of six nalidixic acid-resistant isolates possessed DNA point mutations at either Ser83 or Asp87 in DNA gyrase. One ciprofloxacin-resistant isolate possessed double mutations in DNA gyrase at positions Ser83 and Asp87 as well as a single mutation at Ser80 in parC. The top three serotypes identified, Salmonella Weltevreden (n = 41), Salmonella Newport (n = 13), and Salmonella Lexington (n = 11), were further characterized for genetic relatedness by pulsed-field gel electrophoresis. Fifty-five distinct pulsed-field gel electrophoresis patterns were observed among the 65 isolates, indicating extensive genetic diversity among these Salmonella serotypes contaminating imported foods.

Anti-Bacterial Agents↗