Synthesis and biological evaluation of a mutual prodrug of norfloxacin and fenbufen

Objectives: The study aimed to synthesize a mutual prodrug of norfloxacin and fenbufen with an objective of obtaining an effective and safer anti-inflammatory drug with useful antimicrobial actions

Methods: An amide-based mutual prodrug [NF-FN] was prepared following a single-step synthesis by condensing norfloxacin with fenbufen under appropriate laboratory conditions. Its structure was established on the basis of IR, NMR, Mass spectral data and elemental analysis. The prodrug [NF-FN] was evaluated for in-vitro antibacterial activity against two grampositive [Staphylococcus aureusand Bacillus subtilis] and two gram negative bacterial strains [Escherichia coli and Klebsiella pneumonia]. The in-vivo antiinflammatory activity and ulcerogenicity of the synthesized prodrug were investigated in Wistar albino rats at the doses of 10 and 30 mg/kg body weight, respectively

Results: The synthesized prodrug [NF-FN] showed very good activity against S. aureus and E. coli with MIC-6.25 mg/ mL, and good activity against B. subtilis and K. pneumonia with MIC-12.5 mg/mL. Its anti-inflammatory activity was found to be better than that of the parent drug fenbufen. It was also observed to less severe on gastric mucosa in comparison to reference drug, fenbufen

Conclusion: The prodrug showed promising results as anti-inflammatory agent however, its antibacterial action was found to be slightly weaker than the other parent drug norfloxacin

In vitro evaluation of antimicrobial activity of Kutajghan vati - an Ayurvedic formulation

The present investigation focuses to determine the antimicrobial potential of an Ayurvedic formulation Kutajghan vati. In this study the activity of this formulation was compared with the standard antibiotics like Amikacin and Norfloxacin. Ethanol, methanol and acetone extract of Kutajghan vati demonstrated good antimicrobial activity and thus can form the basis for the development of a novel antibacterial formulation

Comparison of antibiotic resistance and virulence factors in pigmented and Non-pigmented Pseudomonas aeruginosa / Comparación de la resistencia antibiótica y los factores de virulencia en las Pseudomonas aeruginosa pigmentadas y no pigmentadas

OBJECTIVES: Pseudomonas aeruginosa produces multiple virulence factors that have been implicated in pathogenesis and quorum sensing. The aim of this study was to determine differences in the virulence factors of pigmented and non-pigmented P aeruginosa isolates. METHODS: Associations were assessed between pigment production (pyocyanin and pyoverdin) and production of DNase, elastase, lipase, protease, siderophore, twitching motility, antibiotic resistance patterns and virulence-associated genes in 57 non-duplicate P aeruginosa isolates from wounds, sputum, urine, high vaginal swab (HVS), ear, eye and respiratory tract swabs and aspirates of peritoneum and ulcers. RESULTS: Most (82.5%) of the isolates produced either pigment. Pigmented isolates produced more frequently and significant more (p < 0.05) DNase, elastase, lipase protease, and siderophore. Imipenem was the only antibiotic to which all isolates were susceptible (p < 0.05), while 93% and 32% were resistant to tetracycline and norfloxacin, respectively. There was however no significant difference between pigmented and non-pigmented isolates when antibiotic resistance was compared. While isolates had multiple virulence-associated genes, exoS (51%), rhlA (37%) and rhlB (46%) were the predominant genes detected. Except for exoY, genes were present in pigmented isolates more frequently than in non-pigmented isolates. CONCLUSION: The results of this study suggest that antibiotic resistance per se might not be associated with the pigment production in P aeruginosa. However, pigment production appeared to be more significantly associated with multi-drug resistance, presence ofvirulence-associated genes, and expression ofcertain virulence factors, most notably elastase, protease, siderophore and DNase activity. Since pigment production is easy to determine, this might to be a good starting point to identify the virulence status ofan isolate.

OBJETIVO: Pseudomonas aeruginosa produce múltiples factores de virulencia que han estado implicados en patogénesis y detección de quórum (quorum sensing). El objetivo de este estudio fue determinar las diferencias en los factores de virulencia de aislados de P aeruginosa pigmentada y no pigmentada. MÉTODO: Se evaluaron las asociaciones entre la producción de pigmentos (piocianina y pioverdina) y la producción de Dnasa, elastasa, lipasa, proteasa, sideróforos, motilidad asociada a superficies (twitching), patrones de resistencia antibiótica, y genes asociados con virulencia en 57 aislados de P aeruginosa no duplicados, de heridas, esputo, orina, exudado vaginal, exudados de oídos, ojos, y vías respiratorias, y aspirados de peritoneo y úlceras. RESULTADOS: La mayor parte (82.5%) de los aislados produjeron uno de los pigmentos. Los aislados pigmentados produjeron con mayor frecuencia y más significativamente (p < 0.05). Dnasa, elastasa, lipasa, proteasa, y siderósforos. Imipenem fue el único antibiótico al que todos los aislados eran susceptibles (p < 0.05), mientras que el 93% y el 32% fueron resistentes a la tetraciclina y a la norfloxacina, respectivamente. Sin embargo, no hubo diferencia significativa entre los aislados pigmentados y los no pigmentados cuando se comparaba la resistencia antibiótica. Si bien los aislados tenían múltiples genes asociados con la virulencia, exoS (51%), rhlA (37%) y rhlB (46%) fueron los genes predominantes detectados. Con excepción de exoY, los genes estuvieron presentes en aislados pigmentados con mayor frecuencia que en los aislados no pigmentados. CONCLUSIÓN: Los resultados de este estudio sugieren que la resistencia antibiótica per se podría no estar asociada con la producción de pigmentos en P aeruginosa. Sin embargo, la producción de pigmentos parecía estar asociada más significativamente con la resistencia a las multidrogas, la presencia de genes asociados con la virulencia, y la expresión de ciertos factores de virulencia, en particular la actividad de la elastasa, la proteasa, los sideróforos, y la Dnasa. Puesto que la producción de pigmentos es fácil de determinar, esto podría ser un buen punto de partida para identificar el estado de virulencia de un aislado.

Quinolone-resistant Escherichia coli

Quinolones (nalidixic acid - NAL, norfloxacin - NOR, ciprofloxacin - CIP and gatifloxacin - GAT) were tested against Escherichia coli isolated from urine (385 patient samples) by disk diffusion (DD) and agar dilution (AD) methods. Fifty-three samples (13.8 percent) were classified as resistant to at least one of the quinolones tested. CIP and NOR susceptibilities were the same (91.4 percent) and they were similar to GAT (92.7 percent). Susceptibility to NAL, detected by the disk diffusion method, was used to predict susceptibility to NOR, CIP and GAT by the agar dilution method. The sensitivity and specificity of NAL were 100 percent and 95 percent, respectively. Twelve samples were analyzed for mutations in the quinolone resistance-determining region (QRDR) of the gyrA and parC genes. Sequencing of these genes failed to find any mutations in the quinolone-sensitive isolates. However, three mutations were observed in the isolates resistant to all the quinolones tested - two in gyrA and one in parC. A single mutation in gyrA was found in the strains that were resistant to nalidixic acid but fluoroquinolone-sensitive. These findings support the suggestion that NAL could be used as a marker for susceptibility to fluoroquinolones in routine microbiology laboratories. The overall resistance rate to quinolones in the present study was 13.8 percent, which is higher than that observed in other studies carried out in developed countries. Our findings serve as a warning that resistance to this group of antimicrobial agents is increasing.

Comparative evaluation of antiproliferative activity and induction of apoptosis by some fluoroquinolones with a human non-small cell lung cancer cell line in culture.

Lung cancer is the leading cause of cancer- related death in the world today. Since the effective management of drug resistant lung cancer, and particularly non-small cell lung carcinomas is a major problem, attempts need to be made to identify new potential anticancer drugs that can kill non-small cell lung cancer cells efficiently. In the present study, a human non-small cell lung carcinoma NCI-H460 cell line was used to evaluate the antiproliferative activity of Fluoroquinolones like Enoxacin, Norfloxacin, Ciprofloxacin and Levofloxacin. As determined by Sulphorodhamine B assay (SRB assay), all Fluoroquinolones caused cellular growth inhibition in a concentration and time-dependent manner. Enoxacin was found to be the most effective Fluoroquinolone followed by Norfloxacin, Ciprofloxacin and Levofloxacin. Growth inhibitory effects were also found to be independent of the concentrations of serum growth factors in culture medium or variation of initial cell seeding density and proved to be irreversible in nature. Appearance of rounded cells with altered morphology and cell surface blebbing indicated cell killing by apoptosis. Cell shrinkage, nuclear condensation & fragmentation, and cytoplasmic blebbing as indicated by MGG staining confirmed this to be the case. Thus, this investigation clearly demonstrated that the NCI-H460 human non-small cell lung carcinoma cell line is highly sensitive to Fluoroquinolone treatment. The Fluoroquinolones used in this study which are clinically used as antibacterial agents, can also inhibit tumor cell growth suggesting their potential use in a strategy for cancer treatment which might help in controlling cancer.

Quinolone susceptibility of Vibrio cholerae O1 & O139 isolates from Vellore.

BACKGROUND & OBJECTIVES: Vellore is an endemic area for cholera. The relative prevalence of clinical cases of Vibrio cholerae O1 and O139 has been fluctuating. Few studies have examined the susceptibility of local isolates to quinolones. The objective of the present study was to look at quinolone susceptibility and determine MIC of ciprofloxacin to representative clinical isolates of V. cholerae O1 and O139 in Vellore, obtained between 1997 and 1999. METHODS: Antimicrobial susceptibility testing of V. cholerae strains was performed by disc diffusion technique and MIC determination by E test. RESULTS: Five of 30 O1 and all the O139 serogroup isolates were susceptible to nalidixic acid. All isolates of both serogroups were sensitive to norfloxacin. All isolates of both serogroups gave MIC results in the susceptible range to ciprofloxacin; the MICs being lower for V. cholerae O139 (MIC50 = 0.004 microgram/ml and MIC90 = 0.047 microgram/ml) than for O1 serogroup (MIC50 = 0.38 microgram/ml and MIC90 = 0.5 microgram/ml). INTERPRETATION & CONCLUSION: V. cholerae O1 and O139 show differences in quinolone susceptibility, the reason for this is not clear. This could be because of longer exposure of the O1 serogroup to quinolone antimicrobials as compared to the O139 serogroup.

Antibiotics sensitivity pattern of N. gonorrhoeae with special emphasis on norfloxacin and ciprofloxacin.

The current study is carried out to find the in-vitro susceptibility of N. gonorrhoeae to Ciprofloxacin, Norfloxacin, Gentamycin etc. in 110 isolates obtained from acute gonococcal urethritis confirmed by smear examination. The isolates obtained are from the patients attending the Skin and STD Clinic of a teaching hospital, clinically diagnosed as suffering from acute gonococcal urethritis. Antibiotic susceptibility test was done by Kirby Bauer disc diffusion technique. Four to five similar well isolated colonies of the gonococcal strains were picked up with a wire loop and transferred to 5 cc of sterile trypticase soya broth (TSB). Tubes were incubated at 36 degrees C. GC agar base plates were inoculated with suspensions using a sterile cotton swab. Antibiotic discs were placed on these plates. The plates were incubated at 35 degrees C for 18-24 hours in a candle jar with 5-10% CO2. The plates were then observed to note the zones of inhibition around the discs. 87.27% of isolated strains were inhibited by norfloxacin at an MIC of 0.06 mu gm/ml; 89.08% of the strains were inhibited by ciprofloxacin at an MIC of 0.025 mu gm/ml. All the strains (110) were inhibited by ciprofloxacin at a concentration of 0.2 mu gm/ml. Gentamycin sensitivity was 86.36%. Out of 110 patients, 85 were treated with norfloxacin of which 81 (95.29%) were cured. Twenty five were treated with ciprofloxacin of which 24 (96%) were cured. This study shows high sensitivity of N. gonorrhoeae to norfloxacin and ciprofloxacin.

Aumento da frequência de resistência à norfloxacina e ciprofloxacina em bactérias isoladas em uroculturas / Increase in the frequency of norfloxacin and ciprofloxacin resistance of bacteria isolated from urine culture

Objetivo. Avaliar mudanças, ao longo dos anos, na freqüência de resistência à norfloxacina e ciprofloxacina em bactérias isoladas de uroculturas. Métodos. Resultados de todas as uroculturas com crescimento bacteriano de pelo menos 10(5) unidades formadoras de colônias por mL de urina (UFCmL), realizadas no Serviço de Nefrologia da Universidade Federal da Bahia durante o período 1983-1994, foram analisadas. As bactérias incluídas na análise foram aquelas mais freqüentemente isolados: Escherichia coli (n=668), Klebsiella spp. (n=286), Staphylococcus spp. (n=186), Proteus spp. (n=135) e Enterobacter spp. (n=129). Resultados. A freqüência de bactérias resistentes à norfloxacina foi de 3,2 por cento, no período 1983-1986; 5,9 por cento, no período 1987-1990; e 9,1 por cento no período de 1991-1994 (p<0,05). Klebsiella spp. e Enterobacter spp. foram as bactérias que apresentaram maiores aumentos na freqüência de resistência à norfloxacina. Para a ciprofloxacina, constatou-se resistência em 7,4 por cento das bactérias isoladas, no período 1985-1989, e 16,5 por cento, no período 1990-1994 (p<0,05). Esse aumento na freqüência de bactérias resistentes à ciprofloxacina foi mais marcante para Enterobacter spp. e Staphylococcus spp. Conclusoes. Os resultados do presente estudo mostram um aumento gradual na freqüência de resistência à norfloxacina e ciprofloxacina entre as bactérias mais comumente isoladas em uruculturas. A influência do uso prévio de quinolonas e de peculiaridades da bactéria infectante, nesses achados, representa importante questao a ser investigada.

Norfloxacin induced resistance to fluoroquinolones & structurally unrelated antimicrobial agents in coagulase negative staphylococci.

Nine clinical isolates of coagulase negative staphylococci (CONS) susceptible to norfloxacin (MIC 1.8-2 micrograms/ml) were manipulated in vitro to induce norfloxacin resistance by means of serial passage in brain heart infusion broth containing increasing concentrations of norfloxacin. Exposure of CONS to norfloxacin resulted in 18 to 20 times increase in MIC of norfloxacin and change in in vitro susceptibility to ciprofloxacin, pefloxacin, ofloxacin, kanamycin, neomycin and tobramycin, indicating development of cross resistance to fluoroquinolones and aminoglycosides. These results show that exposure to increasing concentrations of norfloxacin can induce the development of resistance to various antimicrobial agents, suggesting its mutagenic role.

In vitro susceptibility of multiple drug resistant Salmonella typhimurium to newer fluroquinolone derivatives.

A total of 105 strains of Salmonella typhimurium resistant to Ampicillin, Co-trimoxazole and Nalidixic acid were included in the present study. Among the new line of Fluroquinolones resistance to Ciprofloxacin (3.8%), Norflox (16.19%) and Ofloxacin (24.76%) was very low as compared to older antibiotics. All the 3 fluoroquinolones had MIC values less than 1 mcg/ml.

Beta-lactamase producing bacterial cystitis: bacteriological profile and in vitro activity of norfloxacin

Cystitis infections caused by beta-lactamase producing bacteria were studied, it accounted for 279/355 [78. 6%] of all cystitis cases, 102 were outpatients and 187 were inpatients. The most prevalent isolated organisms were, K. pneumoniae, S. marcescens, E. coIi. P. aeruginosa and S. coagulase +ve. The in vitro activity of norfloxacin as a member of fluoroquinolones was determined, it was resisted in 48/279 [17.2%] of the isolates compared to 209/279 [74. 9%] for nalidixic acid and 192/279 68.8% for trimethoprim S. methoxazole. A higher incidence of norfloxacin resistance was found in K. pneumoniae and P. aeruginosa. The comparative potency of norfloxacin versus nalidixic acid revealed that the MIC[90] of norfloxacin is 4 folds less than the MIC[90] nalidixic acid. Norfloxacin could be considered in more effective irradication of the bacterial causes of cystitis specially those caused by Beta-lactamase producing bacteria

Antibiotic susceptibility pattern of gonococcal isolates.

A total of 151 isolates of gonococcal urethritis were processed for antibiotic susceptibility pattern by single disc diffusion technique. 17.88% isolates were found to be penicillinase producing Neisseria gonorrhoeae. Only 82.12% and 94.04% of the isolates were sensitive to penicillin and gentamicin respectively, whereas all the isolates were sensitive to fluoroquinolones namely norfloxacin and ciprofloxacin.

Correlation between inhibitory effect of quinolones and mycolic acid metabolism in mycobacteria.

Mycolic acids are important components having a significant role in maintaining the rigidity of mycobacterial cell wall. They could also be the barrier for penetration of certain drugs into the bacterial cell. A novel in vitro model system was established for assessing the effect of Ciproflaxacin on mycolic acid metabolism in pathogenic mycobacteria M. Kansasii (which has similar mycolic acid pattern to that from M. leprae) and the effect of norfloxacin in M. intracellulare. These test mycobacteria were exposed in their midlogarithmic phase of growth to 0.5, 1, 2, 3, 4, 5 and 6 micrograms ml of ciprofloxacin and norfloxacin respectively for 1, 2 and 24 hours. Ciprofloxacin completely inhibited the synthesis of mycolates in M. kansasii at 3, 4 and 5 micrograms/ml; whereas norfloxacin exhibited its maximum inhibitory action on mycolic acids in M. intracellulare at 6 micrograms/ml for all the durations of exposure. Inhibition of mycolates directly correlated with bacterial viability which was estimated by colony forming units. The effect of quinolones on mycolic acid metabolism appears to be direct and not secondary to DNA gyrase. The results obtained from this study and our previous findings show that mycolic acid metabolism is affected by various groups of drugs, whose primary sites of activity may be different. The findings of the present study may have significant therapeutic implications in leprosy and other mycobacterial diseases.

Fluorquinolonas: gênese, mecanismo de açäo e uso terapêutico / Fluorquinolones: genesis, mechanism of action and therapeutic use

Revisao sucinta das fluorquinolonas, com ênfase em sua gênese, mecanismo de açao, atividade farmacológica, farmacocinética, efeitos adversos, interaçoes medicamentosas e principais propriedades dos comercializados no Brasil: ciprofloxacino, lemofloxacino, norfloxacino, ofloxacino e pefloxacino.

Susceptibilidad antimicrobiana de cepas de Escherichia coli uropatogenas en mujeres adultas / Antimicrobial susceptibility of Escherichia coli cepa uropatogenic in adult women

En el período comprendido entre enero a noviembre de 1991 se aislaron 121 cepas bacterianas de urocultivos de 211 mujeres ambulatorias (entre 14 a 60 años) que presentaban por lo menos dos de los siguientes síntomas: disuria, polaquiuria y tenesmo. El 61.2 por ciento de los aislamientos fueron de formas primarias y el 33.1 por ciento de formas recurrentes de infección urinaria. Se aisló mas frecuentemente Escherichia coli (83.5 por ciento) seguido de Klebsiella sp (5.8 por ciento), Staphylococcus saprophyticus (4.1 por ciento)., Se determinó la susceptibilidad de las cepas de Escherichia coli usando las concentraciones mínimas inhibitorias. La susceptibilidad a norfloxacina fué 100 por ciento, nitrofurantoína 95 por ciento, ácido nalidíxico 94.1 por ciento, cefalotina 72.3 por ciento, ampicilina 61.4 por ciento, cotrimoxazol 48.5 por ciento, tetraciclina 37.6 por ciento, gentamicina 98 por ciento y cloranfenicol 46.5 por ciento. No se encontró diferencia significativa entre las susceptibilidades antimicrobianas de las cepas aisladas de infecciones primarias versus recurrentes (p mayor 0.10). De nuestros resultados recomendamos que para el tratamiento de las infecciones urinarias en mujeres ambulatorias adultas no debe usarse cotrimoxazol ni tetraciclina. Se debe realizar estudios de costo-efectividad con los antibióticos norfloxacina, nitrofurantoína y ácido nalidíxico para determinar el mejor esquema terapéutico y los antimicrobianos de elección

Susceptibility pattern of bacterial isolates to lomefloxacin.

The in vitro susceptibility pattern with respect to lomefloxacin was determined in case of 1009 bacterial isolates from clinical specimens with varying susceptibility to commonly used antimicrobial agents. The MIC50 and MIC90 values of lomefloxacin for the Gram negative bacilli showed susceptibility value ranging between 0.12 to 4.0 micrograms/ml, while 90 per cent of the streptococci tested were inhibited only at 16 micrograms/ml. Lomefloxacin was comparable in activity to enoxacin and ciprofloxacin but it was more active than norfloxacin and nalidixic acid.

Failure of norfloxacin to eradicate intestinal colonization of non-typhoidal salmonella in infants.

Infant colonization with non-typhoidal Salmonella (NTS) is common and eradication is problematic. Oral norfloxacin has promising properties for solving this problem, though it has potential toxicity to infants. The drug has been available in Thailand since 1987. Since then, some infants who had diarrhea or NTS colonization were treated with oral norfloxacin 15-20 mg/kg/day for 3-5 days on individual physician's judgement. This observational study was performed in infants and children who had NTS in stool, seen at Ramathibodi hospital from September 1987 to February 1988, in order to give preliminary information. Sixteen of 48 infants received oral norfloxacin treatment. Nine infants had established failure of NTS eradication from follow-up rectal swab cultures. Five infants did not have follow-up rectal swab culture, and two had negative culture once on day 7 after treatment. Considering that 7 infants who did not have evidence of bacteriologic failure were free from colonization, the excretion rate during the first two weeks could be estimated as 56 per cent which is not less than the natural history of this disease. This observation suggests failure of oral norfloxacin, 15 mg/kg/day given in 2 divided doses for 3 days, in eradication NTS colonization in infants.

Futuro de las quinolonas en la práctica clínica / Future of quinolones in clinical practice

En los últimos años ha aumentado el interés en las nuevas quinolonas como agentes antimicrobianos. Diversos compuestos se han utilizado y se ha desarrolado un intenso estudio microbiológico, farmacológico y clínico con estos nuevos fármacos. Un informe previo en esta revista, fue dedicado a comunicar la actividad in vitro de algunos de estos compuestos, comparados con aminoglucósidos. Desde la aparición de ese artículo, se ha tenido un considerable avance en el conocimiento de la farmacología de las preparaciones tanto bucales como parenterales. En este trabajo se presenta un panorama lo más completo posible, de los productos que en un futuro próximo podrán estar en la disponibilidad del mercado nacional, de tal manera, que pueda orientarse el conocimiento y posición de cada uno de ellos como son: norfloxacina, pefloxacina, ciprofloxacina, enoxacina y ofloxacina

Actividad antimicrobiana comparativa in vitro de norfloxacina, contra 200 cepas aisladas de urocultivos / Comparative antimicrobial activity in vitro of norfloxacin against 200 strains isolated from urocultures

La actividad in vitro de norfloxacina fue comparada con la del ácido nalidíxico, ácido pipemídico y cotrimoxazol, en contra de 200 bacilos gramnegativos (BGN) patógenos aislados por medio de urocultivos. Norfloxacina mostró ser más activa que los otros antibióticos estudiados. La concentración inhibitoria mínima (CIM) de norfloxacina para el 100% de E. coli fue de 0.5 mcg/ml; el 100% de P. mirabilis se inhibió con 0.25 mcg/ml; el 100% de cepas de Enterobacter con 0.5 mcg/ml, y el 100% de cepas Klebsiella fueron inhibidas por 0.5 mcg/ml; todos estos BGN corresponden al 96.5% del total de cepas estudiadas