Longitudinal Trends in Antimicrobial Susceptibilities Across Long-Term–Care Facilities: Emergence of Fluoroquinolone Resistance

Background: Urinary tract infections (UTIs) are the most common infectious diseases, imposing great costs on the community. Escherichia coli (E. coli) is the most frequent pathogen of UTIs. On the other hand, ciprofloxacin is a wide-spectrum antibiotic, used for the treatment of persistent and recurrent UTIs. Nevertheless, the increasing chromosomal or plasmid resistance of this bacterium has become a major health problem. In this study, we aimed to determine the role of parC, parE, and qnrB genes in ciprofloxacinresistant E. coli isolates from urine samples of patients suffering from UTI. Methods: Midstream urine samples of patients suffering from UTIs, who were referred to Imam Khomeini hospital, Tehran, Iran during May-October 2014, were collected and evaluated for E. coli isolates. All the isolates were subjected to antimicrobial susceptibility testing (AST) by the standard disk diffusion method, according to the clinical and laboratory standards institute (CLSI) 2014 guidelines. The role of chromosomal genes, parC and parE, in addition to plasmid gene qnrB, was determined by polymerase chain reaction (PCR) method and further sequencing. Results: Among 124 patients, 64.5% of UTI cases were positive for E. coli. Based on the AST results, 77.5% of the isolates were resistant to ciprofloxacin. The size of PCR bands was 265 bp for parE, 389 bp for parC, and 268 bp for qnrB genes. Also, the frequency of intact genes among ciprofloxacin-resistant isolates was 90.9% for parC, 97.67% for parE, and 0% for qnrB genes. Some mutations were detected in the chromosomal genes after sequence analysis. Conclusions: This study showed the important role of mutated chromosomal resistant genes in comparison with plasmid genes in the emergence of ciprofloxacin-resistant E. coli strains.

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“…However, previous review studies have reported an increasing trend in resistance to ciprofloxacin in recent years (12).…”

Section: Introductionmentioning

confidence: 95%

The role of parC, parE, and qnrB Genes in Ciprofloxacin-Resistant Escherichia coli Isolates from Urinary Tract Infections

Iranzad

Hakemi-Vala

2017

Arch Pediatr Infect Dis

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“…Long-term care facilities are also emerging as major reservoirs of both antimicrobial use and bacterial resistance (25,96,156). Antimicrobial stewardship programs may fail to affect hospital resistance rates if importation of resistant organisms from the community and long-term care facilities is significant, since the programs have no control over antimicrobial use in these settings.…”

Section: Enhanced Understanding Of the Relationship Between Antimicromentioning

confidence: 99%

Antimicrobial Stewardship Programs in Health Care Systems

2005

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SUMMARY Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance. With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. The design of antimicrobial management programs should be based on the best current understanding of the relationship between antimicrobial use and resistance. Such programs should be administered by multidisciplinary teams composed of infectious diseases physicians, clinical pharmacists, clinical microbiologists, and infection control practitioners and should be actively supported by hospital administrators. Strategies for changing antimicrobial prescribing behavior include education of prescribers regarding proper antimicrobial usage, creation of an antimicrobial formulary with restricted prescribing of targeted agents, and review of antimicrobial prescribing with feedback to prescribers. Clinical computer systems can aid in the implementation of each of these strategies, especially as expert systems able to provide patient-specific data and suggestions at the point of care. Antibiotic rotation strategies control the prescribing process by scheduled changes of antimicrobial classes used for empirical therapy. When instituting an antimicrobial stewardship program, a hospital should tailor its choice of strategies to its needs and available resources.

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“…Antimicrobial resistance in enteropathogens is a public health problem that has increased in both nosocomial (14,50) and community settings (21), creating barriers to effective therapies (14). There is evidence that changes in antimicrobial use may result in a reduction in the prevalence of resistant bacteria (1,24).…”

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confidence: 99%

Genotypic-Phenotypic Discrepancies between Antibiotic Resistance Characteristics of Escherichia coli Isolates from Calves in Management Settings with High and Low Antibiotic Use

Davis

Besser

Orfe

et al. 2011

Appl Environ Microbiol

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We hypothesized that bacterial populations growing in the absence of antibiotics will accumulate more resistance gene mutations than bacterial populations growing in the presence of antibiotics. If this is so, the prevalence of dysfunctional resistance genes (resistance pseudogenes) could provide a measure of the level of antibiotic exposure present in a given environment. As a proof-of-concept test, we assayed field strains of Escherichia coli for their resistance genotypes using a resistance gene microarray and further characterized isolates that had resistance phenotype-genotype discrepancies. We found a small but significant association between the prevalence of isolates with resistance pseudogenes and the lower antibiotic use environment of a beef cow-calf operation versus a higher antibiotic use dairy calf ranch (Fisher's exact test, P ‫؍‬ 0.044). Other significant findings include a very strong association between the dairy calf ranch isolates and phenotypes unexplained by well-known resistance genes (Fisher's exact test, P < 0.0001). Two novel resistance genes were discovered in E. coli isolates from the dairy calf ranch, one associated with resistance to aminoglycosides and one associated with resistance to trimethoprim. In addition, isolates resistant to expanded-spectrum cephalosporins but negative for bla CMY-2 had mutations in the promoter regions of the chromosomal E. coli ampC gene consistent with reported overexpression of native AmpC beta-lactamase. Similar mutations in hospital E. coli isolates have been reported worldwide. Prevalence or rates of E. coli ampC promoter mutations may be used as a marker for high expanded-spectrum cephalosporin use environments.

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Longitudinal Trends in Antimicrobial Susceptibilities Across Long-Term–Care Facilities: Emergence of Fluoroquinolone Resistance

Cited by 63 publications

References 34 publications

The role of parC, parE, and qnrB Genes in Ciprofloxacin-Resistant Escherichia coli Isolates from Urinary Tract Infections

The role of parC, parE, and qnrB Genes in Ciprofloxacin-Resistant Escherichia coli Isolates from Urinary Tract Infections

Antimicrobial Stewardship Programs in Health Care Systems

Genotypic-Phenotypic Discrepancies between Antibiotic Resistance Characteristics of Escherichia coli Isolates from Calves in Management Settings with High and Low Antibiotic Use

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