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Residual antibiotics reaching the colon can induce severe deleterious effects on the colonic microbiota including the induction of resistance to antibiotics. To avoid the selection of ciprofloxacin resistance, chitosan–iron microspheres were encapsulated into pectin beads with the aim to specifically adsorb residual colonic ciprofloxacin, reducing its time of contact with the endogenous bacteria. In our study, the formulation of beads, their stability as well as their capacity to specifically adsorb ciprofloxacin in simulated digestive media was carried out. Beads incubated in simulated gastric and intestinal media were stable for 1 and 5 h, respectively. When incubated in simulated colonic medium, beads were then degraded by pectinases present in the medium. Coating with Eudragit ® RS was needed to prevent the early adsorption of the antibiotic in intestinal medium. Adsorption studies in simulated colonic medium show that the adsorption capacity of chitosan–iron is not modified after encapsulation within pectin beads making clinically feasible the sequestration of residual ciprofloxacin reaching the colon.

Antimicrobial resistance genes in aquaculture environments have attracted wide interest, since these genes pose a severe threat to human health. This study aimed to explore the possible mechanisms of the ciprofloxacin resistance of Vibrio parahaemolyticus (V. parahaemolytiucs) in aquaculture environments, which may have been affected by the biofertilizer utilization in China. Plasmid-mediate quinolone resistance (PMQR) genes, representative (fluoro)quinolones (FNQs), and ciprofloxacin-resistance isolates in biofertilizer samples were analyzed. The significantly higher abundance of oqxB was alarming. The transferable experiments and Southern blot analysis indicated that oqxB could spread horizontally from biofertilizers to V. parahaemolyticus, and two (16.7%) trans-conjugants harboring oqxB were provided by 12 isolates that successfully produced OqxB. To the best of our knowledge, this study is the first to report PMQR genes dissipation from biofertilizers to V. parahaemolyticus in aquaculture environments. The surveillance, monitoring and control of PMQR genes in biofertilizers are warranted for seafood safety and human health.

BackgroundUrinary tract infection (UTI) caused by resistant bacteria is becoming more prevalent. Few studies are available regarding community-onset UTIs caused by extended-spectrum β-lactamase (ESBL)-producing bacteria in children.Materials and methodsDuring a 5-year period, hospitalized children with community-onset UTI caused by ESBL-producing Escherichia coli (case) and those with non-ESBL-producing E. coli (control) were identified. Patients with long-term care facility stay within the preceding month and those with urine cultures obtained >72 hours after admission were excluded. Clinical features and risk factors associated with the occurrence of ESBL-producing E. coli UTI were reviewed.ResultsThe prevalence of UTI due to ESBL-producing E. coli increased slightly from 0.59% in 2002 to 0.96% in 2006. A total of 104 cases and 208 controls were included for comparison. The ciprofloxacin resistance of the ESBL-producing E. coli increased significantly in this period (p = 0.006). Pre-existing neurological diseases (p

Background/Purpose Typhoid fever is a major cause of disease burden in developing countries. The use of fluoroquinolones, once considered the drugs of choice, should be re-evaluated due to the emergence of quinolone-resistant Salmonella enterica serovar Typhi. In Taiwan, typhoid fever is rare but constitutes an important public health concern. Methods In August 2011, two ciprofloxacin-resistant S. Typhi isolates were identified from one patient who had recently travelled to India. The two isolates together with four other ciprofloxacin-susceptible S. Typhi isolates were subjected for molecular investigation. Polymerase chain reaction (PCR) and sequencing were used to analyze the resistance mechanisms. Pulsed-field gel electrophoresis (PFGE) was performed to delineate the genetic relatedness among the isolates. Results In 2011, a total of 49 typhoid fever cases were reported to the Center for Disease Control in Taiwan, with a significant increase in indigenous cases in northern Taiwan from August to November. In the two S. Typhi isolates with complete resistance to ciprofloxacin [minimum inhibitory concentration (MIC) >32 μg/mL], multiple point mutations in the quinolone resistance-determining regions (QRDRs) of gyrA and parC genes were identified. A unique PFGE pattern was found in the resistant isolates and was different from the other representative susceptible isolates. Conclusions The first ciprofloxacin-resistant S. Typhi infection in Taiwan is reported. The emergence and spread of antimicrobial-resistant S. Typhi infection as a result of international travel may become a threat to public health in Taiwan. Clinicians should be well alert when treating patients who may have acquired resistant infections associated with international travel among endemic regions.

Purpose: Over the last few years, resistance to ciprofloxacin in Salmonella enterica has become a global concern. The present study was undertaken to find out the susceptibility pattern of Salmonella enterica isolates in our hospital. Methods: Blood cultures were done using BacT/ALERT 3D system. The antimicrobial susceptibility testing was carried out by the Kirby-Bauer disc diffusion method using CLSI breakpoints. Minimum inhibitory concentration was determined for ciprofloxacin-resistant strains using E-test and Vitek-1 automated system. Results: A total of 25,953 samples of blood culture yielded 431 Salmonella enterica serotype Typhi and 198 serotype Paratyphi A isolates. Twenty-two isolates of serotype Typhi were resistant to ciprofloxacin, while two isolates of Typhi and two Paratyphi A were intermediately susceptible to ciprofloxacin. Ciprofloxacin resistance is 5.6% (24 isolates) among Salmonella enterica serotype Typhi. Ampicillin, chloramphenicol and co-trimoxazole resistance in Salmonella enterica serotype Typhi appears to have decreased to 14.9% (64/431) in comparison to the 27% (55/205) during 2003. All isolates were sensitive to ceftriaxone. Conclusions: Ciprofloxacin can no longer be considered as the drug of choice in treating Salmonella infections. While first-line antimicrobials may still have a role to play in the treatment of enteric fever, ceftriaxone remains the sole defence against ciprofloxacin-resistant Salmonella infections.

This study investigated the association between prescription of fluoroquinolones and emergence of ciprofloxacin resistance among Escherichia coli isolates in the urine of outpatients from whom a ciprofloxacin-sensitive E. coli strain had been isolated previously. Patients were identified and followed using the healthcare databases of Emilia-Romagna Region, Italy. The outcome of interest was the first isolation from urine of an E. coli strain resistant to ciprofloxacin. Prescription of fluoroquinolones during the previous 6 months was associated independently with the emergence of ciprofloxacin resistance; the strength of the association varied according to individual fluoroquinolone agents.

ObjectiveTo investigate clonal relationships in a nationwide sample of human Enterococcus faecium isolates.MethodsBiochemical fingerprinting (PhP (PhenePlate) typing) was used to compare 180 fecal ampicillin-resistant E. faecium (ARE) isolates with 169 matched fecal ampicillin-susceptible E. faecium (ASE) isolates from patients in 23 hospitals, collected in 1998, and to study 39 fecal ARE isolates from non-hospitalized individuals collected in 1998, and five ARE and 29 ASE isolates from the early 1990s. Representative ARE and ASE isolates were subjected to pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA and sequencing of the regions encoding the fluoroquinolone targets of the enzymes GyrA and ParC.ResultsBoth PhP and PFGE results showed a higher homogeneity among ARE than among ASE isolates (P < 0.001). One PhP type (FMSE1) comprised 73% of the hospital ARE isolates (53% of ARE isolates from non-hospitalized individuals, and four of five ARE isolates from the early 1990s), but only 1% of the ASE isolates. PFGE of the hospital E. faecium isolates revealed that 23 of the 25 ARE isolates and one of the 22 ASE isolates were of one dominating type. High-level resistance to ciprofloxacin (MIC > 16 mg/L) was present in 91% of ARE isolates, whereas only low-level resistance (MIC 4–16 mg/L; 35% of isolates) was found among ASE isolates. One mutation in parC (codon 80) and one of two mutations in gyrA (codons 83 or 87) were detected in all ARE isolates tested with high-level ciprofloxacin resistance, but were lacking in ARE and ASE isolates with low-level ciprofloxacin resistance.ConclusionMost ARE isolates in Sweden were clonally related. High-level ciprofloxacin resistance was found in ARE isolates of PhP type FMSE1 as well as in other PhP types, but never in ASE isolates.

Objective: To evaluate the applicability of nalidixic acid (Nx) resistance in determining reduced susceptibility to ciprofloxacin (Cp) among Salmonella enterica serovar Typhi (S. Typhi) clinical isolates. Methods: The correlation between Cp MIC (minimum inhibitory concentration) values and that Nx, and between Cp MICs and zone diameter of inhibition (ZDI) around 30-毺 g Nx disc for 421 S. Typhi isolates were determined by scattergram analysis. The specificity and sensitivity, in determining Cp reduced-susceptibility, of Nx resistance by disk testing and MIC determination were calculated. Results: For the test S. Typhi isolates the simultaneous presence of Nx-resistance and decreased Cp susceptibility has been recorded. The Nx sensitive S. Typhi isolates were sensitive to Cp; the disc diffusion and MIC breakpoints cannot determine Cp resistance. The sensitivity of Nx disc was 100 %, and the specificity was 89.20 % in determining Cp reduced-susceptibility of S. Typhi isolates; when MICs of Nx were compared with MICs of Cp, the sensitivity and specificity of the approach were 100 % and 95.95 %, respectively. Conclusion: Association between Nx-resistance and reduced susceptibility to Cp was noticed (P 曑 0.001) among the S. Typhi isolates, and thus Nx-resistance might be an indication of decreased susceptibility to Cp.

Objective To report on the prevalence of isolates with ciprofloxacin resistance in non-typhoidal salmonellas from humans in England and Wales in 1997. Methods All non-typhoidal salmonellas referred to the Laboratory of Enteric Pathogens in 1997 were screened for resistance to ciprofloxacin at 0.125 and 1.0 mg/L and nalidixic acid at 16 mg/L, and results were compared to those for 1994. Full minimal inhibitory concentrations (MICs) of these antimicrobials were also determined for a selection of isolates resistant to ciprofloxacin at 0.125 mg/L but sensitive at 1.0 mg/L, and for all isolates resistant at 1.0 mg/L. Results Since 1994 there have been increases in the occurrence of resistance to ciprofloxacin (MICs: 0.25-1.0 mg/L) in Salmonella enterica serotypes Enteritidis, Typhimurium, Virchow and Hadar. Of particular importance have been increases in the occurrence of resistance in multiresistant S. Typhimurium DT 104, and also in S. virchow, a serotype with a propensity for causing extraintestinal infections in humans. High-level resistance (MIC≥2.0 mg/L) was uncommon and was identified in only a few strains, all from patients with a history of recent foreign travel. Conclusions There is a strong temporal association between increases in the occurrence of ciprofloxacin resistance in Salmonella serotypes Typhimurium, Virchow and Hadar from humans in England and Wales and with the licensing for use in food animals in the UK of the related fluoroquinolone antibiotic enrofloxacin; in contrast, for S. enteritidis ciprofloxacin resistance was most common in a phage type associated with foreign travel. It is hoped that recent recommendations for the use of fluoroquinolone antimicrobials in food animals in the UK will result in a reduction in the occurrence of resistance to ciprofloxacin in zoonotic salmonellas causing infections in humans.

OBJECTIVE: To report an unexpectedly high number of cases of septicemia with Stomatococcus mucilaginosus, and try to identify predisposing factors. METHODS: All blood cultures obtained during 1991--93 from patients treated at the hematologic ward were bacteriologically identified. The medical records of patients with S. mucilaginosus-positive blood cultures were retrospectively reviewed and evaluated. The antibiotic susceptibility pattern and restriction fragment length polymorphism (RFLP) of S. mucilaginosus were tested. RESULTS: S. mucilaginosus blood isolates from patients with hematologic malignancies were found to be as common as isolates of Staphylococcus aureus. Eleven patients with myelogenous leukemia and isolation of S. mucilaginosus from the blood are reported on. One patient had concomitant meningitis. All patients were neutropenic and most had oral mucositis and had been given ciprofloxacin prophylaxis. S. mucilaginosus isolates from these patients were resistant to ciprofloxacin in contrast to isolates from patients who had received other prophylactic regimens and seven isolates found in healthy individuals not recently treated with antibiotics. The resistant S. mucilaginosus were found to be of diverse genetic origin as determined by RFLP. CONCLUSIONS: The appearance of resistant strains during ciprofloxacin prophylaxis may be a predisposing factor for S. mucilaginosus septicemia. There was no evidence of a nosocomial spread of S. mucilaginosus strains.

Aim To analyse the ciprofloxacin resistance pattern in Pseudomonas aeruginosa in a hospital population over 12 years. Method The microbiology laboratory database of P. aeruginosa isolated from clinical specimens was reviewed for three sentinel years (1994, 1999 and 2005). Organism identification and resistance was determined by either/or: BioMerieux Vitek, Becton Dickinson Phoenix, Kirby Bauer disk diffusion, AB Biodisk E-test, Becton Dickinson Pasco and/or Dade Behring MicroScan. Microsoft Excel was used for data analysis. Results The study included 2358 P. aeruginosa strains from 1346 patients. The most common specimen source for 1994 and 1999 was urine, and sputum for 2005.Ciprofloxacin resistance rates were 20.9% for 1994, followed by a slight increase to 26.3% for 1999 to level off at 27.1% for 2005. Resistance rates were highest in urine isolates for 1994 and fluids in 1999 and 2005. In every sentinel period, highest resistance rates were seen in the elderly. Discussion Ciprofloxacin resistance rates showed little increase over a 12 year surveillance period. Since ciprofloxacin resistance in P. aeruginosa was seen most often in the elderly, we advise caution when prescribing quinolones for these patients. Resistance rates remained unaffected by a region-wide antibiotic control initiative implemented between 1999 and 2005. This unexpected finding warrants further studies.

Despite mankind's continuing efforts to find better and more powerful antimicrobial agents, bacteria continue to find ways to resist these agents. Recent examples include the emergence of plasmid-mediated resistance to third generation cephalosporins in E. coli, K. pneumoniae and Salmonella; the emergence of plasmid-mediated beta-lactamase in E. faecalis; the appearance of ciprofloxacin resistance among methicillin-resistant staphylococci; and, perhaps most threatening, the appearance of vancomycin resistance in E. faecalis and E. faecium, at least some of which is plasmid mediated. These examples demonstrate the continuing need for studies of resistance and for new compounds, and the need for new stategies in managing bacterial infections.