Ciprofloxacin Sensitivity Research Articles

A randomized comparative study of single-dose fosfomycin and 5-day ciprofloxacin in female patients with uncomplicated lower urinary tract infections

Uncomplicated lower urinary tract infections (UTIs) are the most frequent infections in females. Increased resistance rates against commonly used antibiotics have led to the use of novel antimicrobials. The aim of the present study was to evaluate the bacteriological and clinical effects of single-dose fosfomycin trometamol (FMT) and 5-day ciprofloxacin in females with uncomplicated UTIs. In this randomized comparative study, 260 female patients between 18 and 65years of age enrolled, of whom 142 completed the study. The most frequently isolated bacterial pathogen in the urine cultures of patients were Escherichia coli (82.3%) and Enterobacter spp. (8.4%). FMT sensitivity was 94% and ciprofloxacin sensitivity was 59% in Escherichia coli; in comparison, FMT sensitivity was 75% and ciprofloxacin sensitivity was 50% in Enterobacter spp. The MIC90 for FMT was 4μg/ml. Of the 142 patients, 77 were treated with FMT and 65 were treated with ciprofloxacin. The clinical remission rate was 83% in the FMT group and 81% in the ciprofloxacin group; the bacterial eradication rate was 83% in the FMT group and 78% in the ciprofloxacin group, and there was no significant difference between the two study groups. In conclusion, a single dose of FMT (at 3g) was as effective as ciprofloxacin, at 500mg twice a day for 5days, in the treatment of uncomplicated lower UTIs. It was concluded that the use of FMT as a first-line treatment in the empirical treatment of uncomplicated UTIs might have a positive impact on the problem of resistance to other antibiotics.

Enteric fever in a UK regional infectious diseases unit: A 10 year retrospective review

Enteric fever is an increasingly common diagnosis in returning travellers in the UK. We performed a retrospective descriptive study of culture-confirmed cases of enteric fever admitted to University Hospitals Leicester, UK between January 1999 and April 2009. 100 cases of enteric fever were identified in adults (n = 76) and children (n = 24). The median age of adult subjects was 38 (range 18-71) and 55% were male. Of the 61 adult cases with notes available, 60 (98.3%) were of Asian ethnicity and 56 (92%) had a recent travel history, principally to the Indian Subcontinent. Symptoms included fever (100%), headache (62%), diarrhoea (59%) and abdominal pain (44%). Common examination findings included pyrexia and mild generalized abdominal tenderness. Mild hyponatraemia, transaminitis and a normal white cell count were commonly identified. Reduced ciprofloxacin sensitivity was common and increased over the study period. Median fever clearance time was 6 days, and treatment failure occurred in 20% of cases. Relapse occurred in 2 patients. Complications were unusual, and one patient died. Patients with enteric fever presented with a non-specific febrile illness within one month after returning from travel, and most had an uncomplicated clinical course. Increasing ciprofloxacin insensitivity was the likely explanation for a high treatment failure rate and this agent can no longer recommended as empirical treatment.

Etiological analysis of ocular non-viral microbial isolates in children and their antibiotics susceptibility in vitro

To analyze the types, distribution characteristics and in vitro susceptibility of antibiotic agents of ocular non-viral microbial isolates in children. Experimental research.785 specimens obtained from children below the age of 14 in Beijing Tongren Hospital during 1999 to 2004 were cultured and identified for bacterium, fungus and Acanthamoeba respectively at Beijing Institute of Ophthalmology. Microbial culture-positive rate, susceptibility patterns and the organisms distribution of positive cultures were retrospectively analyzed. The results were statistical analyzed by chi(2). Of the 785 specimens, 211 were culture positive. The percentage of positive culture was 26.88%. Of those positive cultures, 176 (83.41%) had pure bacterial infections, 32 (15.17%) had pure fungal infections, and 3 (1.42%) had pure cultures of Acanthamoeba. Of the 176 bacterial positive cultures, polymicrobial infection was present in 38 cases (33 bacterial, 5 fungal and bacterial). Of 214 bacterial isolates, the most common isolate was Neisseria gonorrhoeae (39/214, 18.22%), followed by Staphylococcus epidermidis (37/214, 17.29%), and Corynebacterium spp. (36/214, 16.82%). The most common fungal pathogen isolated was Fusarium spp. representing 25.00% (8/32) of all positive fungal cultures, followed by Aspergillus spp. (15.63%, 5/32). The sensitivity of tobramycin, norfloxacin, gentamicin, amikacin, ciprofloxacin, ofloxacin, rifampicin and levofloxacin of bacteria was 62.57%, 64.94%, 70.06%, 70.87%, 71.19%, 73.89%, 85.80% and 87.50%. Gram-positive isolates were susceptible to levofloxacin. Gram-negative isolates showed high susceptible to ciprofloxacin, ofloxacin and levofloxacin. The fungal isolates were most susceptible to natamycin, followed by terbinafine, but resistant to fluconazole. Bacteria are the most common pathogens in non-viral microbial eye infection in children. Neisseria gonorrhoeae, Staphylococcus epidermidis, and Corynebacterium spp. are the most common bacterial pathogens, which are highly susceptible to levofloxacin and rifampicin. Fusarium spp. and Aspergillus spp. are the most common fungal pathogens, which are highly susceptible to natamycin but resistant to fluconazole.

Multiple Regulatory Pathways Associated with High-Level Ciprofloxacin and Multidrug Resistance in Salmonella enterica Serovar Enteritidis: Involvement of ramA and Other Global Regulators

Mechanisms of antibiotic resistance were examined in nalidixic acid-resistant Salmonella enterica serovar Enteritidis field isolates displaying decreased susceptibility to ciprofloxacin and in in vitro-derived ciprofloxacin-resistant mutants (104-cip and 5408-cip). All field isolates harbored a single gyrA mutation (D87Y). Deletion of acrB and complementation with wild-type gyrA increased quinolone susceptibility. Selection for ciprofloxacin resistance was associated with the development of an additional gyrA (S83F) mutation in 104-cip, novel gyrB (E466D) and parE (V461G) mutations in 5408-cip, overexpression of acrB and decreased susceptibility to nonquinolone antibiotics in both mutants, and decreased OmpF production and altered lipopolysaccharide in 104-cip. Complementation of mutated gyrA and gyrB with wild-type alleles restored susceptibility to quinolones in 104-cip and significantly decreased the ciprofloxacin MIC in 5408-cip. Complementation of parE had no effect on quinolone MICs. Deletion of acrB restored susceptibility to ciprofloxacin and other antibiotics tested. Both soxS and marA were overexpressed in 104-cip, and ramA was overexpressed in 5408-cip. Inactivation of each of these global regulators lowered ciprofloxacin MICs, decreased expression of acrB, and restored susceptibility to other antibiotics. Mutations were found in soxR (R20H) and in soxS (E52K) in 104-cip and in ramR (G25A) in 5408-cip. In conclusion, both efflux activity and a single gyrA mutation contribute to nalidixic acid resistance and reduced ciprofloxacin sensitivity. Ciprofloxacin resistance and decreased susceptibility to multiple antibiotics can result from different genetic events leading to development of target gene mutations, increased efflux activity resulting from differential expression of global regulators associated with mutations in their regulatory genes, and possible altered membrane permeability.

Oxidative stress induced by ciprofloxacin in Staphylococcus aureus

Staphylococcus aureus with multiple sensitivity to ciprofloxacin, was investigated to detect alterations in the production of superoxide anion (O 2 −), other reactive oxidant species (ROS), and superoxide dismutase (SOD), and to relate them with ciprofloxacin accumulation and sensitivity. Oxidative stress was studied by means of Nitroblue Tetrazolium reaction (NBT) and chemiluminescence (CL); lucigenin was employed to detect O 2 −, and luminol was used to measure other ROS. Sensitive strains exhibited higher intracellular O 2 − increase than resistant ones when incubated with ciprofloxacin. SOD was determined in normal conditions and induction was investigated in the presence of ciprofloxacin. These assays demonstrated that resistant and sensitive strains exported a great amount of SOD and that the induction of SOD intracellular was insufficient to counteract the augment of O 2 − in the cytoplasm of sensitive strains. Accumulation of ciprofloxacin, researched by spectrofluorometry, showed high levels of antibiotic in sensitive strains which increased the O 2 − causing more oxidative stress than in resistant S. aureus.

Invitro antimicrobial susceptibility pattern of bacterial isolates from wound infections in university of Ilorin Teaching Hospital

The outcome of 532 wound swabs received from patients with wound infections in different units of the University of Ilorin Teaching Hospital Ilorin, Nigeria, over a one year period (July 2000 – June 2001), and routinely procesed by Gram staining and culture in the Microbiology Laboratory, is reported. 444(83.5) of all samples cultured positive for bacterial pathogens while 88 (16.5%) were bacteriologically sterile. 272 swabs yielded single isolate while 172 yielded a mixture of two or more organisms. Staphylococcus aureus predominates (35.8%), followed by Pseudomonas spp (21.8%), Escherichia coli (15.3%), Klebsiella spp (13.4%), Proteus spp (5.6%), Coagulase Negative Staphylococci (3.1%), Streptococcus faecalis (2.8%), Streptococcs pyogenes (0.9%), Group B _-haemolytic Streptococci (0.9%), and Acinetobacter spp (0.3%). Both Gram-positive and Gram-negative organisms demonstrated moderate to high in vitro sensitivity to Ofloxacin and Ciprofloxacin (sensitivity rate 70-94%). In vitro sensitivity to Cloxacillin, Erythromycin, Azithromycin and Ceftazidime by Gram positive organisms ranged beween 55 and 90% while Gentamicin, Ceftrazidime and Azithromycin equally demonstrated moderate to high inhibitory effect on Gram negative organisms including Pseudomonas spp. (sensitivity rate 55-90%). The Fluoroquino lones are the favoured antimicrobial agents nowadays, as demonstrated in this study. In our environment however, a combination of Cloxacillin and Gentamicin is an effective empiric alternative when cost is considered and this combination can be used. The need for continuous antimicrobial monitoring of clinical isolates of wound infection for drug resistance, which is of paramount importance in the empiric selection of antibiotics, is emphasized. (Af. J. of Clinical and Experimental Microbiology: 2002 3(1): 6-10)

Increased sensitivity to quinolone antibacterials can be engineered in human topoisomerase IIα by selective mutagenesis

A potential region of drug-DNA interaction in the A subunit of DNA gyrase has previously been identified from crystallographic studies. The local amino acid sequence has been compared with similar regions in yeast topoisomerase II and human topoisomerase IIα. Three non-conserved, potentially solvent-accessible residues at positions 762, 763 and 766 in human topoisomerase IIα lie between well-conserved regions. The corresponding residues in GyrA (83, 84 and 87) have a high frequency of mutation in quinolone-resistant bacteria. Mutations in human topoisomerase IIα have been generated in an attempt to engineer ciprofloxacin sensitivity into this enzyme: M762S, S763A and M766D (each mutated to the identical amino acid present in gyrase), along with an M762S/S763A double mutant and a triple mutant. These enzymes were introduced into a temperature-sensitive yeast strain, deficient in topoisomerase II, for in vivo studies, and were overproduced for in vitro studies. The M766D mutation renders the enzyme incapable of supporting the temperature-sensitive strain at a non-permissive temperature. However, both M766D and the triple mutant enzymes can be overproduced and are fully active in vitro. The double mutant was impaired in its ability to cleave DNA and had reduced catalytic activity. The triple mutation confers a three-fold increase in sensitivity to ciprofloxacin in vitro and similar sensitivities to a range of other quinolones. The activity of the quinolone CP-115,953, a bacterial and eukaryotic topoisomerase II poison, was unaffected by any of these mutations. Mutations in this region were found to increase the sensitivity of the enzyme to the DNA intercalating anti-tumour agents m-AMSA and ellipticine, but confer resistance to the non-intercalating agents etoposide, teniposide and merbarone, an effect that was maximal in the triple mutant. We have therefore shown the importance of this region in determining the sensitivity of topoisomerase II to drugs and have engineered increased sensitivity to quinolones.

Influence of growth rate and nutrient limitation on susceptibility of Burkholderia cepacia to ciprofloxacin and tobramycin.

The influence of growth rate and oxygen availability on ciprofloxacin and tobramycin sensitivity and cell surface hydrophobicity in Burkholderia cepacia was assessed for cells grown in a chemostat under iron-limitation. Whereas susceptibility to both antibiotics decreased with increasing growth rate and oxygen repletion yet increased under oxygen depletion, hydrophobicity decreased with increasing growth rate and oxygen repletion but was relatively unaffected under oxygen depletion. These results emphasize the modulating effect of the growth environment on antibiotic susceptibility and the need to perform antimicrobial susceptibility tests under conditions which closely mimic, in vitro, bacterial growth in vivo.

Fluoroquinolone resistance associated with specific gyrase mutations in clinical isolates of multidrug-resistant Mycobacterium tuberculosis.

Fluoroquinolones are potent antibacterial agents being used clinically against multidrug-resistant tuberculosis. Treatment failure is thought to arise from acquisition of fluoroquinolone resistance by Mycobacterium tuberculosis. A collection of 13 resistant clinical isolates of M. tuberculosis was examined for ciprofloxacin sensitivity relative to controls exhibiting the same IS6110 DNA type. Specific alleles were associated with distinct levels of drug susceptibility for 11 isolates that contained nucleotide changes expected to alter the amino acid sequence of the A subunit of DNA gyrase. Five different gyrA (ciprofloxacin resistance) alleles were present among 7 isolates having the W DNA subtype. These isolates, which are representative of an outbreak strain, constitute a panel of organisms that can be used to evaluate contributions of gyrase and DNA topoisomerase IV to resistance.

Changes in Susceptibility to Ciprofloxacin in a Community in Northern Israel

The fluoroquinolones are orally administered antimicrobial agents introduced in the mid-1980s. Although they are particularly effective for treating Gram-negative bacillary infections, they are also active against Gram-positive organisms, especially Staphylococcus aureusJ11 However, bacterial re­ sistance is emerging as their use increases,l21 An increasing number of Pseudomonas aeruginosa and S. aureus bacteria resistant to fluoroquinolones was rapidly observed, followed, in the last few years, by the emergence of Enterobacteriaceae re­ sistant to these agentsPJ Susceptibility to ciprofloxacin during 1991 to 1993 was measured in a Community MicrobiologTable I. Changes in susceptibility of isolates to ciprofloxacin ical Laboratory in Northern Israel, which served a population of 800 000 inhabitants. 48 636 isolates were tested: 15 829 in 1991,16531 in 1992 and 16 276 in 1993 (table I). Most of the Gram-negative bacteria showed a significant decrease in ciprofloxacin sensitivity during the 2-year follow-up. The sensitivity of other organisms to ciprofloxacin in 1991 and 1993, respectively, was as follows: Escherichia coli, 100 and 95% (p < 0.001); Klebsiella pneumoniae, 100 and 82% (p < 0.001); Enterobacter sp., 98% and 95% (p < 0.01); Proteus mirabilis, 98 and 93% (p < 0.001); Indole-positive Proteus sp., 98 and 95% (p < 0.02); p. aeruginosa, 90 and 84%