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PubMed1981

Studies on the effect of antibiotic substances on leptospires and their cultivation from material with a high bacterial count.

Leptospira species are difficult to isolate from sperm specimens because rapid growth of the contaminant flora will kill the pathogen. The resistance of 5 Leptospira strains to 5 different antibiotics was examined with a view to an inhibition of such contaminant growth. Neomycin (10, 20, 30 mg/l), vancomycin (5, 8, 10 mg/l), nalidixic acid (50, 75, 100 mg/l), streptomycin (5, 8, 10 mg/l) and chloramphenicol (5, 10, 20 mg/l) were added separately to Korthof's culture medium containing rabbit serum. The comparative growth rates of the leptospires were evaluated. Against the control medium, all 5 antibiotics were found to have an adverse influence on the multiplication phase. In conformity with literature data, vancomycin (10 mg/l) and nalidixic acid (50 mg/l) were found to have the lowest effect. In the cases of streptomycin and chloramphenicol, there was a high reduction of the leptospiral count and even a complete lack of multiplication. A combination of vancomycin (10 mg2l) and nalidixic acid (50 mg/l) was used for the recovery of leptospires from porcine sperm. To inhibit a growth of Ps. aeruginosa, 5000 U/l polymyxin B were added. The strongly inhibitory action of polymyxin B on leptospiral growth could be eliminated by subculturing in a medium free from inhibitory substances after 2 days.

Anti-Bacterial Agents↗
PubMed1982

Primary culture media for routine urine processing.

It has been recommended that routine microbiological processing of urine specimens include quantitative plating onto blood agar medium along with a selective and differential agar such as MacConkey agar for gram-negative organisms. Few data have been published to justify this combination. To evaluate the validity of this recommendation 2,553 midstream, clean-voided urine samples were quantitatively plated onto blood agar, MacConkey agar, and colistin-nalidixic acid agar, which is a selective medium for gram-positive organisms. The amounts of growth on each of the three media were compared. Results indicated that the best medium combination was colistin-nalidixic acid agar and MacConkey agar. The use of colistin-nalidixic acid agar instead of blood agar increased the detection of significant growth of enterococci, lactobacilli, and Torulopsis glabrata.

Bacteria↗
PubMed2003

Corneal and scleral permeability of quinolones--a pharmacokinetics study.

PURPOSE: To investigate the corneal and scleral permeability of nalidixic acid and synthesized fluoroquinolones and their in vivo pharmacokinetics in rabbits. METHODS: The corneal and scleral permeability coefficients of ciprofloxacin, norfloxacin, cinoxacin, enoxacin, and ofloxacin were determined in rabbits using high performance liquid chromatography (HPLC). The aqueous humor levels of norfloxacin and ciprofloxacin were measured separately by topical instillation of 0.3% solutions of the two drugs onto rabbit eyes. RESULTS: Nalidixic acid had a higher corneal permeability coefficient (17.3 +/- 3.56 x 10(-6) cm/second) than all other drugs tested (p < 0.01). Corneal permeability coefficients in rabbits among ciprofloxacin, norfloxacin, cinoxacin, enoxacin, and ofloxacin were not significantly different (p > 0.1). Comparing the corneal and scleral permeability coefficients, only values for nalidixic acid were not significantly different (17.35 +/- 3.56 x l0(-6) cm/second versus 22.69 +/- 5.19 x 10(-6) cm/second, p > 0.05), while all other drugs had scleral permeability coefficients 8 to 10 times greater than corneal permeability coefficients. The mean aqueous humor concentration of norfloxacin and ciprofloxacin at 60 minutes to 180 minutes after instillation was around 0.3 microg/mL, a value higher than MIC90 of most bacteria.

Administration, Topical↗
PubMed1996

Efficacy of antimicrobial treatment in non-dysenteric persistent diarrhoea in a community setting.

OBJECTIVES: To determine the efficacy of antimicrobial treatment in non-dysenteric persistent diarrhoea in a community setting. METHODS: In this double-blind field trial, 156 children aged 4-36 months with persistent diarrhoea not associated with Giardia lamblia infestation seeking treatment in a community outpatient clinic, were randomized to receive a combination of nalidixic acid and metronidazole, metronidazole alone, or placebo for 7 days. RESULTS: In comparison with placebo, metronidazole treatment did not result in a significant reduction in the mean post-enrollment diarrhoeal duration and stool frequency, increase in the proportion of patients recovered by days 3, 5 and 7 of treatment, and increase in weight gain at days 7 and 14. Comparing the combination of nalidixic acid and metronidazole with metronidazole alone, 17.5% more children treated with the combination recovered by day 3 of treatment (p = 0.08) and the mean stool frequency ascertained on day 7 for the previous 24 h was 26.8% less in them (p = 0.05). The weight gains at days 7 and 14 were similar in the two groups. CONCLUSIONS: These findings indicate that metronidazole offers no therapeutic benefit in persistent diarrhoea not associated with Giardia lamblia and nalidixic acid has only a modest clinical benefit, which is not substantial enough to warrant its routine use.

Anti-Infective Agents↗
PubMed1970

Effect of putative deoxyribonucleic acid inhibitors on macromolecular synthesis in Saccharomyces cerevisiae.

The effects of inhibitors of bacterial deoxyribonucleic acid (DNA) synthesis upon logarithmically growing cultures of Saccharomyces cerevisiae were investigated. Cell division, ribonucleic acid (RNA) synthesis, and DNA synthesis were measured after addition of nalidixic acid, fluorodeoxyuridine, or phenethyl alcohol to cultures of yeast growing in defined and complex media. Both nalidixic acid and fluorodeoxyuridine had only temporary effects on nucleic acid synthesis in cultures growing in defined medium, and little or no observable effect on cultures growing in complex medium. Neither compound inhibited colony formation on complex solid medium, although growth was slow on defined solid medium. Phenethyl alcohol caused complete inhibition of DNA synthesis, RNA synthesis, and cell division in cultures growing in defined medium. In cultures growing in complex medium, RNA synthesis and cell division were inhibited to a lesser extent. A slight increase in DNA was observed in the presence of the inhibitor.

Adenine↗
PubMed1984

The influence of inhibitors on the repair of benzo[a]pyrene-damaged DNA in hamster tracheal epithelial cells.

We investigated, in a cloned hamster tracheal epithelial cell line HTE-B, the effects of inhibitors of DNA topoisomerase, novobiocin and nalidixic acid; of DNA polymerase, 1-beta-arabinofuranosylcytosine (ara-C) and 2',3'-dideoxythymidine; of ribonucleotide reductase, hydroxyurea; and of poly(ADP-ribose)synthetase, 3-aminobenzamide, upon the removal of benzo[a]pyrene adducted to DNA [B[a]P--DNA]. A substantial reduction in the rate of removal of the polycyclic hydrocarbon-adducts occurred when nalidixic acid was added to the HTE-B cells that had been previously incubated with B[a]P for 8 h. Novobiocin produced a similar, but less marked, effect. The rate of disappearance of the individual B[a]P--DNA adducts was measured by analysis of the h.p.l.c. profiles. Of the 5 major adducts observed under the h.p.l.c. conditions, 4 were reduced in control cells to 30% of the original levels by 24 h after removal of the B[a]P from the medium; adduct 5 was almost completely removed. In the presence of nalidixic acid, during the 24 h repair period, only the removal of adduct 5 was unimpaired; the removal of the other 4 adducts was significantly retarded. On the other hand, 3-aminobenzamide addition did not affect the rate of removal of B[a]P--DNA adducts from the HTE-B cells. We employed the combinations of ara-C and dideoxythymidine or ara-C and hydroxyurea to allow the accumulation of single strand breaks after incubation of the HTE-B cells with B[a]P. These breaks were assayed by alkaline elution analysis. Inclusion of these inhibitors during the 2 h after removal of the B[a]P from the medium resulted in the accumulation of 4-5 single strand breaks/10(10) daltons of HTE-B DNA. This compares with a minimum estimate of the number of adducts removed during this period of 3 adducts/10(7) daltons. This discrepancy may indicate that the majority of lesions are not repaired by a pathway sensitive to polymerase inhibitors. In the presence of 3-aminobenzamide, we routinely observed a 10% increase in the alkaline elution of the DNA obtained from B[a]P-treated cells (1-2 breaks/10(10) daltons). Our results indicate that an excision repair process may be involved in the removal of at least some of the B[a]P-induced damage to DNA. However, the repair of the multiple adducts is complex and may involve pathways other than classical excision repair.

Animals↗
PubMed1991

Biphasic kinetics of bacterial killing by quinolones.

The early phases of the bactericidal dynamics of three quinolones against two Escherichia coli strains were studied. Four concentrations of nalidixic acid, pefloxacin and ofloxacin were tested against each strain. In each case biphasic killing of bacteria was observed after a lag phase, and a biexponential model of microbial death could be fitted to the data. A direct relationship existed between the length of the lag phase and the drug concentration. The other parameters of the model appeared to be either strain-dependent, drug-dependent or both, and were characterised by narrow fluctuations. The degree of killing was always higher for ofloxacin. A paradoxical effect seemed to exist for nalidixic acid and pefloxacin in that survival was greater in the presence of 5 x MIC than in the presence of 3 x MIC. It was clear that ofloxacin did not act in the same way as nalidixic acid and pefloxacin. The study illustrated the relevance of mathematical modelling to investigations of the bactericidal effects of antibiotics.

Colony Count, Microbial↗
PubMed1999

Drug resistance in Campylobacter jejuni, C coli, and C lari isolated from humans in north west England and Wales, 1997.

AIMS: To test the sensitivity of strains of Campylobacter species isolated from humans in England and Wales against a range of antimicrobial agents for the purpose of monitoring therapeutic efficacy and as an epidemiological marker. METHODS: An agar dilution breakpoint technique was used to screen isolates against ampicillin, chloramphenicol, gentamicin, kanamycin, neomycin, tetracycline, nalidixic acid, ciprofloxacin, and erythromycin. Minimal inhibitory concentrations (MIC) were also determined for a sample of quinolone resistant strains. RESULTS: Approximately 50% of strains tested were resistant to at least one drug. Strains which were resistant to four or more of the drugs tested were classified as multiresistant; this occurred in 11.3% of C jejuni, 19.9% of C coli, and 63.6% of C lari. Resistance to erythromycin occurred in 1.0% of C jejuni and 12.8% of C coli. Resistance to quinolones occurred in 12% of strains, with a ciprofloxacin MIC of > 8 mg/l and a nalidixic acid MIC of > 256 mg/l; a further 4% of strains had intermediate resistance with a ciprofloxacin MIC of between 0.5 and 2 mg/l (fully sensitive strains, 0.25 mg/l or less) and a nalidixic acid MIC of between 32 and 64 mg/l (fully sensitive strains, 8 mg/l or less). CONCLUSIONS: Resistance to quinolones in campylobacters from human infection may relate to clinical overuse or use of fluoroquinolones in animal husbandry. Both veterinary and clinical use should be reconsidered and fluoroquinolone drugs used only as a treatment for serious infections requiring hospital admission. Erythromycin resistance is still rare in C jejuni but much more common in C coli.

Aminoglycosides↗
PubMed1980

[Susceptibility of Pseudomonas aeruginosa recently isolated from clinical specimens to various antimicrobial agents and changes of susceptibility to carbenicillin, gentamicin and amikacin (author's transl)].

We estimated the minimum inhibitory concentrations of following twenty-one antimicrobial agents against 161 strains of Pseudomonas aeruginosa isolated from clinical specimens during 1979. Antimicrobial agents were 5 penicillins (carbenicillin, sulbenicillin, piperacillin, apalcillin and ticarcillin), 3 cephalosporins (cefsulodin, cefoperazone and ceftizoxime), 5 aminoglycosides (gentamicin, tobramycin, dibekacin, amikacin and kanamycin), 3 tetracycclines (tetracyline, doxycycline and minocycline), chloramphenicol, colistin, polymyxin B, nalidixic acid and pipemidic acid. Among penicillins piperacillin and apalcillin showed strongest antibacterial activity and the activity of carbenicillin was weakest. Highly resistant strains against carbenicillin increased rapidly until 1975. Among cephalosporins cefsulodin showed strongest antibacterial activity and its activity was stronger than piperacillin. Antibacterial activity of cefoperazone and ceftizoxime were weaker than cefsulodin, but stronger than carbenicillin and sulbenicillin. Among aminoglycosides kanamycin showed very weak antibacterial activity, but another four drugs showed very strong activity. But resistant strains against these four drugs increased gradually and over 20% of strains was resistant to gentamicin. Among gentamicin, tobramycin and dibekacin cross-resistance was observed, but not between amikacin and these three drugs. Recently the number of strains resistant to both amikacin and gentamicin increased. Tetracyclines, chloramphenicol and nalidixic acid showed rather weak activity, but colistin and polymyxin B showed very strong activity and resistant strains against these drugs were very few. Pipemidic acid showed rather stronger activity than nalidixic acid, but its activity was weaker than aminoglycosides excluding kanamycin.

Amikacin↗
PubMed2000

Salicylate induction of phenotypic resistance to quinolones in Serratia marcescens.

The influence of salicylic acid on the permeability and susceptibility of Serratia marcescens to both nalidixic acid and ciprofloxacin was studied, as well as the effect of salicylate on outer membrane proteins and lipopolysaccharide. As salicylic acid concentration increased, ciprofloxacin accumulation decreased with a concomitant, previously observed, reduction in the porin content of the outer membrane. Resistance to ciprofloxacin and nalidixic acid was enhanced when bacteria grew in the presence of salicylic acid.

Anti-Infective Agents↗
PubMed2004

Acquisition and epidemiology of antibiotic-resistant Escherichia coli in a cohort of newborn calves.

OBJECTIVES: The acquisition of antibiotic-resistant commensal Escherichia coli was examined in a cohort of newborn calves. METHODS: Faecal samples were collected weekly from calves over a 4 month period and screened for E. coli resistant to ampicillin, apramycin and nalidixic acid at concentrations of 16, 8 and 8 mg/L, respectively. E. coli viable counts were performed on samples from a subset of calves. RESULTS: All calves acquired ampicillin- and nalidixic acid-resistant E. coli, while only 67% acquired apramycin-resistant E. coli during the study. Sixty-seven per cent of samples were resistant to at least one of the three antibiotics. Prevalence of ampicillin and nalidixic acid resistance was high initially and declined significantly with age (P < 0.001). No temporal or age-related pattern was observed in the prevalence of apramycin resistance. Housing the cohort had a significant effect on the prevalence of nalidixic acid resistance (P < 0.001). Total and ampicillin- and nalidixic acid-resistant E. coli counts declined with calf age (P < 0.001), with the rate of decline in ampicillin-resistant counts being greater than that for total counts (P < 0.001). The proportion of total E. coli counts that were resistant to ampicillin or nalidixic acid also declined with age (P < 0.001). CONCLUSIONS: Cohort calves rapidly acquired antibiotic-resistant bacteria within days of birth. Carriage of resistant bacteria was associated with both age and housing status of the cohort.

Ampicillin↗
PubMed1997

[Prevention of reinfection by L-methionine in patients with recurrent urinary tract infection].

PROBLEM: A great variety of different antimicrobial chemotherapeutics is available for the treatment of urinary tract infections. Influencing the course of chronic diseases is a problem because recurrent diseases may result in disturbances of renal and bladder functions as well as in irreversible damages of the renal parenchyma. The present investigations are expected to clarify whether an effective prevention of reinfection in patients with chronically recurrent urinary tract infection is possible by a regular administration of L-methionine (Acimethin). PATIENTS AND METHODS: 33 female patients were included in the examinations. Following acute disease, 23 females (aged: 47.4 +/- 13.3 years) were treated with 3 x 1 tablet of Acimethin (L-methionine) daily over a period of 26 months. Ten female patients (aged: 47.4 +/- 12.2 years) taking 1 tablet of Nevigramon (nalidixic acid) three times daily over 21.6 months served as a control group. Before starting treatment and in the middle of the therapy period control examinations were performed and following the last drug administration so as to assess the therapeutic result. RESULTS: No acute infection occurred during L-methionine treatment. All parameters of inflammation (leucocyte count, C-reactive protein, blood sedimentation rate, alpha 2-globulin concentration) were in the normal range; no impairment of renal function was observed. Although L-methionine, i.e. nalidixic acid, did not yield any significant changes in the range of bacteria, the adherence of uropathogenic microorganisms to the cells of the urinary tract was reduced. Before L-methionine treatment, the average load of the uroepithelial cells was 95.9 +/- 73.6 bacteria per cell. When the observation period was completed, 51.2 +/- 56.4 bacteria per cell were registered (p < 0.03). During nalidixic acid treatment, the rate of adherence was reduced from 74.0 +/- 88.4 to 34.4 +/- 37.8 bacteria per cell (p < 0.25). During L-methionine treatment, no Escherichia coli strains that are able to produce hemolysin or to form aerobactine were found. Among agents adhering to uroepithelial cells, however, an increase in their ability to produce mannose-resistant hemagglutination was conspicuous. CONCLUSION: L-methionine is suitable to prevent reinfection with chronic urinary tract infection. The therapeutic result is essentially due to its influence on bacterial cytoadherence. In contrast to the established recommendations concerning the prevention of reinfection by the use of antibiotics and sulphonamides selecting resistant strains during long-term treatment, nothing is known about the development of resistance to L-methionine.

Adult↗
PubMed2003

Widespread antibiotic resistance in savannah Nigeria.

There is minimal data on antibiotic resistance from savannah northern Nigeria. A retrospective study of 438 patients seen in 12 months (2000) with microbial pathogens from urinary and respiratory tracts was undertaken. Antibiotic susceptibilities were determined using stokes disc diffusion technique. Resistance in Escherichia coli (E. coli) reached 91-96% to cotrimoxazole, tetracycline and ampicillin but was 11%, 17% and 28% to colistin, nitrofurantoin and nalidixic acid. Resistance of other uropathogens (Klebsiella and Proteus spp) reached 83-99% to cotrimoxazole, tetracycline and ampicillin but was 14-40% to colistin, nitrofurantoin and nalidixic acid. Pneumococci were non-susceptible to penicillin (93%), cotrimoxazole (92%), tetracycline (84%), ampicillin (53%), chloramphenicol (21%) and cefazolin (8%). Antibiotic resistance is widespread in savannah northern Nigeria. Resistance is less to chloramphenicol, colistin, nalidixic acid, nitrofurantoin and the latter generation cephalosporins and quinolones than to penicillin, ampicillin, cotrimoxazole and tetracycline.

Adult↗
PubMed1999

In vitro activities of cephalosporins and quinolones against Escherichia coli strains isolated from diarrheic dairy calves.

The in vitro activities of several cephalosporins and quinolones against 195 strains of Escherichia coli isolated from diary calves affected by neonatal diarrhea were determined. One hundred thirty-seven of these strains produced one or more potential virulence factors (F5, F41, F17, cytotoxic necrotizing factor, verotoxin, and the eae gene), but the remaining 58 strains did not produce any of these factors. From 11 to 18% of the E. coli strains were resistant to cephalothin, nalidixic acid, enoxacin, and enrofloxacin. However, cefuroxime, cefotaxime, and cefquinome were highly effective against the E. coli isolates tested. Some significant differences (P < 0.05) in resistance to quinolones between the strains producing potential virulence factors and nonfimbriated, nontoxigenic, eae-negative strains were found. Thus, eae-positive, necrotoxigenic, and verotoxigenic (except for nalidixic acid) E. coli strains were significantly more sensitive to nalidixic acid, enoxacin, and enrofloxacin than nonfimbriated, nontoxigenic, eae-negative strains. Moreover, eae-positive strains were significantly more sensitive to enoxacin and enrofloxacin than F5-positive strains. Thus, the result of this study suggest that the bovine E. coli strains that produce some potential virulence factors are more sensitive to quinolones than those that do not express these factors.

4-Quinolones↗
PubMed2004

Current pattern in antimicrobial susceptibility of Salmonella Typhi isolates in Pondicherry.

Typhoid fever continues to remain a health problem as the causative organism Salmonella Typhi has developed resistance to many of the antibiotics used. This study was undertaken to determine the current pattern of resistance to antimicrobial agents and phage types of S.Typhi isolates obtained in a tertiary health care hospital in Pondicherry. Blood culture was done for 1296 suspected cases of enteric fever and 157 strains of S. Typhi were isolated. Sensitivity to ampicillin, chloramphenicol, gentamicin, ciprofloxacin and ceftriaxone was determined by disc diffusion, and the minimum inhibitory concentration (MIC) of ciprofloxacin determined. There were 61 multidrug resistant (MDR) isolates. The MIC of ciprofloxacin for 147 isolates was >0.5 mg/l; of these, 131 were resistant to nalidixic acid. Phage typing was done for 123 isolates and 115 were found to be of phage type E1, biotype 1. A decline in the number of MDR isolates was noted. Concurrently, there has been an increase in the number of isolates sensitive to all antibiotics except nalidixic acid, and all these isolates showed reduced susceptibility to ciprofloxacin. Nalidixic acid susceptibility could be a useful screening test for the detection of decreased susceptibility of S. Typhi to ciprofloxacin. The clinicians should be advised to use ceftriaxone selectively in cases showing non-responsiveness to ciprofloxacin.

Anti-Infective Agents↗
PubMed2001

Bacterial aetiology and anti-microbial resistance of childhood diarrhoea in Yemen.

In a 12-month period, 561 stool cultures from Yemeni children aged 1-60 months and presenting with diarrhoea, were analysed to identify the bacterial aetiology and their anti-microbial resistance to the commonly used antibiotics. A total of 190 (33.9 per cent) were positive for bacterial culture. Most of the positive cultures (58 per cent) were from children aged 1-12 months. The majority of the positive cultures were enteropathogenic Escherichia coli (58.4 per cent) Salmonella spp., and Shigella spp. (20 per cent each). Campylobacter were found to be an extremely uncommon agent of childhood diarrhoea making only 1.6 per cent of the positive cultures. The majority of the Salmonella were group C (60.5 per cent) and group B (29 per cent). Of the Shigella isolates, 13 (34 per cent) were S. flexneri, and seven (18 per cent) S. dysentrea. More than two-thirds of the Salmonella isolates were resistant to nalidixic acid, chloramphenicol, co-trimoxazole, gentamicin, and amoxycillin, while 42 per cent were resistant to cefotaxime. Most of the Shigella isolates were susceptible to nalidixic acid and cefotaxime, and resistant to the other antibiotics. All the tested enteropathogenic E. coli isolates were resistant to amoxycillin, 83 per cent were resistant to co-trimoxazole, 62 per cent to chloramphenicol, and 54 per cent to gentamicin, while only 16 and 6 per cent were resistant to nalidixic acid and cefotaxime, respectively. This study, the first in Yemen, draws attention to the urgent need of a national surveillance system, essential for the containment of anti-microbial resistance.

Age Distribution↗