Do we need an intravenous fluoroquinolone?

Intravenous ciprofloxacin, the first parenteral fluoroquinolone available in this country, represents another class of antimicrobial agents from which physicians must choose when treating nosocomial infections. Fluoroquinolones are bactericidal antimicrobial agents that act by inhibiting DNA gyrase. They are active in vitro against most gram-negative bacteria and methicillin-susceptible staphylococci. Activity against anaerobic bacteria and streptococci is poor. The rapid development of bacterial resistance in centers with high quinolone usage is of great concern. Resistance develops most commonly in Pseudomonas aeruginosa and staphylococci. Resistance emerges most often when quinolones are used to treat chronic infections or in patients with poorly drained abscesses, necrotic tissue, or indwelling catheters. Clinical trials have shown ciprofloxacin to be as effective as ceftazidime in the treatment of infections caused by gram-negative bacteria. Although the overall frequency of side effects to fluoroquinolones is low, seizures and allergic reactions have been attributed to their use. Ciprofloxacin inhibits the metabolism of theophylline, and morbidity and death have been reported in patients taking the two drugs concomitantly. Parenteral fluoroquinolones should be reserved for the treatment of gram-negative bacterial infections in patients in whom standard agents cannot be used.     

Structure Based In Silico Analysis of Quinolone Resistance in Clinical Isolates of Salmonella Typhi from India

Enteric fever is a major cause of morbidity in several parts of the Indian subcontinent. The treatment for typhoid fever majorly includes the fluoroquinolone group of antibiotics. Excessive and indiscriminate use of these antibiotics has led to development of acquired resistance in the causative organism Salmonella Typhi. The resistance towards fluoroquinolones is associated with mutations in the target gene of DNA Gyrase. We have estimated the Minimum Inhibitory Concentration (MIC) of commonly used fluoroquinolone representatives from three generations, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin, for 100 clinical isolates of Salmonella Typhi from patients in the Indian subcontinent. The MICs have been found to be in the range of 0.032 to 8 μg/ml. The gene encoding DNA Gyrase was subsequently sequenced and point mutations were observed in DNA Gyrase in the quinolone resistance determining region comprising Ser83Phe/Tyr and Asp87Tyr/Gly. The binding ability of these four fluoroquinolones in the quinolone binding pocket of wild type as well as mutant DNA Gyrase was computationally analyzed by molecular docking to assess their differential binding behaviour. This study has revealed that mutations in DNA Gyrase alter the characteristics of the binding pocket resulting in the loss of crucial molecular interactions and consequently decrease the binding affinity of fluoroquinolones with the target protein. The present study assists in understanding the underlying molecular and structural mechanism for decreased fluoroquinolone susceptibility in clinical isolates as a consequence of mutations in DNA Gyrase.     

Clinical and bacteriological profiles of patients with typhoid fever treated during 1975-1998 in the Tokyo Metropolitan Komagome Hospital

Patients with typhoid fever presenting to the Tokyo Metropolitan Komagome Hospital during the period 1975-1998 were retrospectively investigated. All cases were diagnosed by a positive culture for Salmonella typhi in either of their clinical specimens. Of the total number of 130 patients, 57% contracted the disease abroad; this population increased in later years as the total numbers of cases decreased. The period from disease onset to diagnosis averaged 14 days with 20% of the cases requiring over three weeks to establish a diagnosis. As for symptomatology relative bradycardia was seen in less than half of the cases, and rose spots or splenomegaly in less than one third. A positive blood culture was the most frequent test establishing the diagnosis followed by a positive stool culture. Intestinal bleeding was recognized in as many as 35 cases (27%) and even intestinal perforation occurred in two cases (1.5%). Chloramphenicol was most commonly employed during the early study period, however, during the late period it was replaced by fluoroquinolones. The clinical cure rate was 98% with regimens that include fluoroquinolones/quinolone; however it was 87% with the other antimicrobial regimens. Bacteriological relapse occurred in 25% of the non-fluoroquinolone group while only in 2.0% in the fluoroquinolone/quinolone group. Four strains of Salmonella typhi that were multi-resistant to chloramphenicol, ampicillin and cotrimoxazole were isolated in travelers from Asia. Early diagnosis by appropriate bacteriological examination regardless of classical symptomatology should be stressed and the use of fluoroquinolones is warranted in the treatment of typhoid fever.     

New insights into fluoroquinolone resistance in Mycobacterium tuberculosis: functional genetic analysis of gyrA and gyrB mutations

Fluoroquinolone antibiotics are among the most potent second-line drugs used for treatment of multidrug-resistant tuberculosis (MDR TB), and resistance to this class of antibiotics is one criterion for defining extensively drug resistant tuberculosis (XDR TB). Fluoroquinolone resistance in Mycobacterium tuberculosis has been associated with modification of the quinolone resistance determining region (QRDR) of gyrA. Recent studies suggest that amino acid substitutions in gyrB may also play a crucial role in resistance, but functional genetic studies of these mutations in M. tuberculosis are lacking. In this study, we examined twenty six mutations in gyrase genes gyrA (seven) and gyrB (nineteen) to determine the clinical relevance and role of these mutations in fluoroquinolone resistance. Transductants or clinical isolates harboring T80A, T80A+A90G, A90G, G247S and A384V gyrA mutations were susceptible to all fluoroquinolones tested. The A74S mutation conferred low-level resistance to moxifloxacin but susceptibility to ciprofloxacin, levofloxacin and ofloxacin, and the A74S+D94G double mutation conferred cross resistance to all the fluoroquinolones tested. Functional genetic analysis and structural modeling of gyrB suggest that M330I, V340L, R485C, D500A, D533A, A543T, A543V and T546M mutations are not sufficient to confer resistance as determined by agar proportion. Only three mutations, N538D, E540V and R485C+T539N, conferred resistance to all four fluoroquinolones in at least one genetic background. The D500H and D500N mutations conferred resistance only to levofloxacin and ofloxacin while N538K and E540D consistently conferred resistance to moxifloxacin only. Transductants and clinical isolates harboring T539N, T539P or N538T+T546M mutations exhibited low-level resistance to moxifloxacin only but not consistently. These findings indicate that certain mutations in gyrB confer fluoroquinolone resistance, but the level and pattern of resistance varies among the different mutations. The results from this study provide support for the inclusion of the QRDR of gyrB in molecular assays used to detect fluoroquinolone resistance in M. tuberculosis.     

Results of the study on antibiotic resistance emergence among pathogens of community-acquired urinary tract infections in Moscow. Phase I]

A rise of resistance in uropathogens to all agents used for the management of urinary tract infections has been observed in Moscow. However, because of the broad spectrum and favourable safety parameters, fluoroquinolones remain the drugs of choice for the treatment of community-acquired urinary tract infections. Among them levofloxacin is preferable. When the use of fluoroquinolones is contraindicated, the 1st-3rd generation cephalosporins are advisable. Nitrofurans are expedient in the treatment of acute and relapsing cystitis. By the antibacterial activity and bioavailability sodium furasidin is advantages among the nitrofurans.     

Photophysical and phototoxic properties of the antibacterial fluoroquinolones levofloxacin and moxifloxacin

Two antibacterial fluoroquinolones, levofloxacin and moxifloxacin, were investigated to evaluate their photophysical properties and to explore the mechanism of their phototoxicity. Photophysical experiments were carried out in aqueous solution by stationary and time-resolved fluorimetry, and by laser flash photolysis, to obtain information on the various decay pathways of the excited states of the drugs and on transient species formed upon irradiation. The results obtained show that levofloxacin is able to photosensitize red blood cell lysis in an oxygen-independent way and induce a high decrease in cell viability after UVA irradiation, although to a lesser degree than the racemic mixture ofloxacin. Moxifloxacin, which is an 8-MeO-substituted fluoroquinolone, is less phototoxic than the other compounds. Cellular phototoxicity was inhibited by the addition of superoxide dismutase, catalase, and free radical and hydroxyl radical scavengers (BHA, GSH, mannitol, and DMTU), indicating the involvement of superoxide anion and/or a radical mechanism in their cytotoxicity. A good correlation was observed between lipid peroxidation, protein photodamage, and cellular phototoxicity, indicating that test compounds exert their toxic effects mainly in the cellular membrane. Experiments carried out on pBR322 DNA show that these derivatives do not significantly photocleave DNA directly, but single-strand breaks were evidenced after treatment of photosensitized DNA by two base-excision-repair enzymes, and Endo III.     

Review of the in vitro activity and potential clinical efficacy of levofloxacin in the treatment of anaerobic infections

The activity of levofloxacin against aerobic bacteria has been well documented both in vitro and clinically, but its anaerobic activity has been infrequently studied. This new fluoroquinolone exhibits good in vitro activity (MIC(S) < or =2.0 microg/mL) against many anaerobic pathogens associated with acute sinusitis, bite wounds, and other soft-tissue infections. It is less active against Bacteroides fragilis (MIC (90)=2-4 microg/mL ) and has poor inhibitory activity against non-fragilis B. fragilis group species that are associated with gastrointestinal and genitourinary tract infections. Levofloxacin does not antagonize the in vitro activity of clindamycin and metronidazole and often provides additive or synergistic activity against anaerobic bacteria with these agents. In pharmacodynamic models, levofloxacin exhibits rapid bactericidal activity at 2-4 times the MIC of anaerobic bacteria. Prolonged killing is observed when the area-under-the concentration-time-curve to MIC ratio is greater than 40. In clinical efficacy trials, levofloxacin has been effective in the treatment of patients with gynecologic, skin and skin-structure, and bone infections involving anaerobic pathogens. Both micro-biologic and pharmacodynamic studies support further evaluations of levofloxacin in the treatment of selective mixed aerobic/anaerobic infections.     

Chlorpromazine alone and with reserpine; use in the treatment of mental diseases

One hundred psychiatric patients were treated with chlorpromazine, alone or combined with reserpine. Fifty-six per cent of patients with chronic schizophrenic reactions showed moderate or pronounced improvement when treated with chlorpromazine alone. The results of treatment with the combined drugs were not so good as that. Indications are that treatment of patients with chronic schizophrenic reactions is more efficacious with these drugs than with other forms of somatic therapy. Complications of treatment were far greater with combined use of chlorpromazine and reserpine. For this reason, the combination appears to have limited usefulness. The Parkinson syndrome was the most frequent complication of large doses of these drugs. It appears to be a toxic reaction, requiring reduction in dosage. Jaundice appears to be neither a frequent nor a serious complication of treatment.     

CHLORPROMAZINE ALONE AND WITH RESERPINE—Use in the Treatment of Mental Diseases

One hundred psychiatric patients were treated with chlorpromazine, alone or combined with reserpine. Fifty-six per cent of patients with chronic schizophrenic reactions showed moderate or pronounced improvement when treated with chlorpromazine alone. The results of treatment with the combined drugs were not so good as that. Indications are that treatment of patients with chronic schizophrenic reactions is more efficacious with these drugs than with other forms of somatic therapy.Complications of treatment were far greater with combined use of chlorpromazine and reserpine. For this reason, the combination appears to have limited usefulness. The Parkinson syndrome was the most frequent complication of large doses of these drugs. It appears to be a toxic reaction, requiring reduction in dosage. Jaundice appears to be neither a frequent nor a serious complication of treatment.     

Fluoroquinolones and propionic acid derivatives induce inflammatory responses in vitro

Fluoroquinolones and propionic acid derivatives are widely used antibacterials and non-steroidal anti-inflammatory drugs, respectively, which have been reported to frequently trigger drug hypersensitivity reactions. Such reactions are induced by inflammatory mediators such as cytokines and chemokines. The present study investigated whether levofloxacin, a fluoroquinolone, and loxoprofen, a propionic acid derivative, have the potential to induce immune-related gene expression in dendritic cell-like cell lines such as HL-60, K562, and THP-1, and immortalized keratinocytes such as HaCaT. The expression of IL-8, MCP-1, and TNFα messenger RNA (mRNA) was found to increase following treatment with levofloxacin or loxoprofen in HL-60 cells. In addition, these drugs increased the mRNA content of annexin A1, a factor related to keratinocyte necroptosis in patients with severe cutaneous adverse reactions. Inhibition studies using specific inhibitors of mitogen-activated protein (MAP) kinases and NF-κB suggest that the extracellular signal-regulated kinase (ERK) pathway is the pathway principally involved in the induction of cytokines and annexin A1 by levofloxacin, whereas the involvement of MAP kinases and NF-κB in the loxoprofen-induced gene expression of these factors may be limited. Fluoroquinolones and propionic acid derivatives that are structurally related to levofloxacin and loxoprofen, respectively, were also found to induce immune-related gene expression in HL-60 cells. Collectively, these results suggest that fluoroquinolones and propionic acid derivatives have the potential to induce the expression of immune-related factors and that an in vitro cell-based assay system to detect the immune-stimulating potential of systemic drugs might be useful for assessing the risk of drug hypersensitivity reactions.     

UROLOGICAL PROBLEMS IN THE AGED

The preponderance of men over 60 years of age on the Urology Service at the Los Angeles County General Hospital is due to the prevalence of prostatic disease. Approximately two-thirds of patients with prostatic hypertrophy of Grade I or smaller size and who have less than 60 cc. of residual urine can be treated nonsurgically. Prostatic operation, when done expertly, is well tolerated by most aged patients. The end results are usually good except in those who have complicating central nervous system lesions. The approach chosen for removal of the prostate is determined by the training and experience of the surgeon.Urinary obstruction due to carcinoma of the prostate can be relieved by hormonal treatment in most cases. Carcinoma of the bladder when discovered early can be controlled for many years by repeated transurethral resection and frequent observation; when discovered late, successful definitive treatment is rarely possible. Vesical dysfunction due to neurological and/or senile changes is best treated by use of an in-dwelling urethral catheter. Mild dysfunction may respond somewhat to medication and sphincter muscle exercise. Infections respond well to anti-infection drugs unless there is an organic urological lesion. Untoward reactions to drugs are more common in aged patients. Calculi, when they are found in the bladder, should be crushed and evacuated; when in the kidney, let alone unless symptoms are annoying. Renal tumors should be removed unless the patient is more than 80 years of age. Elderly patients tolerate urological operation well when it is done expertly.     

The synergic modeling for the binding of fluoroquinolone antibiotics to the hERG potassium channel

The fluoroquinolone antibiotic binding site in the hERG potassium channel was examined for the residues involved and their position in the tetrameric channel. The blocking effect of the two fluoroquinolones levofloxacin and sparfloxacin to tandem dimers of the hERG mutants were evaluated electrophysiologically. The results indicated that two Tyr652s in the neighboring subunits and one or two Phe656s in the diagonal subunits contributed to the blockade in the case of both compounds, and Ser624 was also involved. The docking studies suggested that the protonated carboxyl group in the compounds strongly interacts with Phe656 as a π acceptor.     

Drug treatment of Parkinson's disease.

A wide variety of drugs is available for treating Parkinson''s disease, including anticholinergics, amantadine levodopa, dopamine agonists, and selegiline. In younger patients (less than 50) levodopa is usually delayed provided that adequate relief of symptoms can be achieved with other drugs. In older patients (greater than 70) levodopa should be started as soon as symptom relief is required. Between these ages there is no consensus, but at present most such patients should probably be given controlled release levodopa before a dopamine agonist is added. Fluctuations can often be alleviated by giving controlled release preparations of levodopa, by giving small doses at frequent intervals, by adding selegiline or a long acting oral agonist, or by subcutaneous apomorphine. Dyskinesia can be peak dose, diphasic, or "off period." The diphasic form is hardest to alleviate. Psychiatric side effects should initially be managed by changing the antiparkinsonian treatment before resorting to antipsychotic drugs.     

Competitive binding of fluoroquinolone antibiotics and some other drugs to human serum albumin: a luminescence spectroscopic study

Co‐administration of several drugs in multidrug therapy may alter the binding of each to human serum albumin (HSA) and hence their pharmacological activity. Thirty‐two frequently prescribed drug combinations, consisting of four fluoroquinolone antibiotics and eight competing drugs, have been studied using fluorescence and circular dichroism spectroscopic techniques. Competitive binding studies on the drug combinations are not available in the literature. In most cases, the presence of competing drug decreased the binding affinity of fluoroquinolone, resulting in an increase in the concentration of free pharmacologically active drug. The competitive binding mechanism involved could be interpreted in terms of the site specificity of the binding and competing drugs. For levofloxacin, the change in the binding affinity was small because in the presence of site II‐specific competing drugs, levofloxacin mainly occupied site I. A competitive interference mechanism was operative for sparfloxacin, whereas competitive interference as well as site‐to‐site displacement of competing drugs was observed in the case of ciprofloxacin hydrochloride. For enrofloxacin, a different behavior was observed for different combinations; site‐to‐site displacement and conformational changes as well as independent binding has been observed for various drug combinations. Circular dichroism spectral studies showed that competitive binding did not cause any major structural changes in the HSA molecule. Copyright © 2013 John Wiley & Sons, Ltd.     

Platinum(II) complexes with fluoroquinolones: Synthesis and characterization of unusual metal-piperazine chelates

The fluoroquinolones constitute an important class of synthetic antimicrobial agents. The interaction between these compounds and metallic cations has been investigated primarily with the goal of identifying the functional groups directly linked to the metal. Furthermore, there has been some additional work investigating the effect of metal ions upon antibacterial activity. The vast majority of the metallic complexes reported in the literature show coordination of the fluoroquinolone through the carboxylate and the carbonyl oxygen atoms. In this work, we report the synthesis and characterization of platinum(II) complexes with ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin, and gatifloxacin. The resulting complexes present the fluoroquinolone coordinated through the nitrogen atoms of the piperazine ring, which is unusual. The proposed structures were supported by spectroscopic evidence (IR, NMR, and mass spectra) as well as by theoretical studies.     

Antibiotic therapy in children with pertussis]

The data accumulated within the last years required revision of the indications to the use of antibiotics in treatment of pertussis. One of the aims of antibiotic therapy in pertussis was to prevent colonization of B. pertussis in the respiratory tracts. With that end in view the choice of antibiotics should be limited by those, to which the pathogen is the most sensitive i.e. erythromycin, ampicillin and augmentin. Comparative efficacy of erythromycin and ampicillin during the first 2 weeks of the disease was studied in 79 infants at the age not older than 1 year with pertussis and it was shown that erythromycin was advantageous by its therapeutic activity and less side effects. Expedience of the antibiotic therapy during the spastic period for providing a preventive effect on development of bronchopulmonary complications was studied in 201 patients with pertussis. No preventive effect of the antibiotics on development of the bronchopulmonary complications defined by the secondary bacterial flora was recorded. In the group of the patients treated with the antibiotics prophylactically (group 1) the complications were 2.6 times more frequent than in the patients treated with pathogenetic agents alone (group 2). Intrahospital pneumonia developed in 8.9 per cent of the patients in group 1 and in 1.5 per cent of the patients in group 2. Therefore, antibiotics should not be used at the late periods of pertussis for prophylaxis of secondary bacterial complications.     

Chemotherapy of Campylobacter infections]

A total of 600 patients with suspected alimentary food poisoning were hospitalized. The ++clinico-laboratory findings showed that 27 (4.5 per cent) of them had Campylobacter infection. The cultures of Campylobacter jejuni and Campylobacter coli were isolated from 24 and 3 patients, respectively. The patients underwent complex pathogenetic treatment with oral rehydration saline solutions, symptomatic agents, enzymatic preparations and diet (the basic therapy) supplemented with biological bacterial preparations in less severe cases (8 patients). Antibacterial drugs such as furazolidone (roxytromycin), gentamicin and levomycetin, as well as fluoroquinolones such as ofloxacin and ciprofloxacin were additionally used in the treatment of both the patients with the generalized infection and those with more severe processes of the disease, pronounced diarrhea with blood traces and persisting isolation of Campylobacter (12 patients). The most favourable results in the treatment of more severe patients with Campylobacter infection were obtained with the fluoroquinolones used after inadequately efficient therapy with furazolidone or antibiotics especially in the cases with repeated isolation of campylobacteria.     

Fluoroquinolones and their importance in modern chemotherapy of infectious diseases

Experimental and clinical data on antibacterial drugs belonging to fluorine derivatives of quinolone carboxylic acid (quinolones of the third generation) were summarized. Brief characteristics of their antibacterial activity and experimental data on chemotherapeutic activity of pefloxacin, a fluoroquinolone on models of septicopyemia and meningoencephalitis in experiments with mice infected by P. aeruginosa, Staphylococcus and Klebsiella are presented. High efficacy of pefloxacin was shown and its advantages over dioxidine and gentamicin on the model of meningoencephalitis were revealed. The main indications to the use of fluoroquinolones, possible adverse reactions and contraindications to the use of the drugs of that group are described.     

Medical Assistance to the Aged

Aerosol therapy has three principal objectives: Mobilization of bronchial secretions, relief of bronchospasm and topical chemotherapy. It has become an important tool in the treatment of bronchopulmonary diseases. The equipment for inhalation therapy, however, should be adequate. Both large-capacity and small-capacity nebulizers must be available, and they must be the kind that will produce a mist with most of its particles only 0.5 to 2.5 micra in diameter. These nebulizers may be used alone or in conjunction with a variety of appliances that will deliver the aerosols to the respiratory tract. The use of humidifying agents as aerosols is extremely helpful in patients with retained bronchopulmonary secretions. In some patients who have particularly thick or gelatinous secretions and in patients with mucoviscidosis, ordinary water or saline solution is often not enough. Hypertonic saline may be of value in these cases, and it is suggested that half-molar (2.9 per cent) saline be administered in 10 per cent propylene glycol. In these cases, preparations containing detergents (tyloxypal) or other preparations containing enzymes (desoxyribonuclease or trypsin) may be given by the aerosol technique, with care not to cause irritation.The bronchodilator aerosol agents are of proved benefit in the treatment of bronchospastic disorders and are indicated in most cases of asthma and in those cases of emphysema in which there is definite evidence of associated bronchospasm.The value of the aerosol method of administering chemotherapeutic and antibiotic drugs has probably been overrated, and it is suspected that much of the benefit previously attributed to the therapeutic agent was actually a result of humidification and liquefaction.