Ciprofloxacin Resistance Rates Research Articles

Gonorrhea: Data on antibiotic resistance and accompanying infections at the University Hospital Dresden over a 10‐year time period

Over the last years, growing resistance of gonorrhea to quinolones has emerged worldwide. Currently, cases with resistance to oral and parenteral third-generation cephalosporins are increasingly reported. Because gonorrhea is not a notifiable infection in Germany, data on epidemiology and antimicrobial surveillance of gonorrhea are scarce. We present the results of N. gonorrhoea testing at the University Hospital Dresden over the course of ten years. The results of cultural and nucleic acid amplification testing of gonorrhea and accompanying infections of 1,850 smears between 2001 and 2010 were analyzed retrospectively. Among 181 patients (mean age 30.4 years) 159 had positive PCR analyses for gonorrhea and 50 positive cultures of Neisseria gonorrhoea. The rate of ciprofloxacin resistance was high (in 46% of all isolates), primarily in men. Resistance to cefotaxime and ceftriaxone could not be detected so far. In 40% of the cases at least one accompanying urogenital infection occurred, predominantly with Chlamydia trachomatis. Similar to other regions of Germany, a high percentage of resistance to quinolones was found in gonorrhea, but not to cephalosporins. Additionally, accompanying infections were frequent and warrant screening. In the light of recent cases of resistance to cephalosporins currently emerging in Europe, cultural diagnosis of gonorrhea should definitely be intensified by all means. The results should be integrated into a surveillance system.

Prevalence of Ciprofloxacin Resistance Among Gram-Negative Bacilli at a Specialist Hospital in Saudi Arabia

Background: Resistance to antimicrobials of different structural classes including fluoroquinolones has arisen in a multitude of bacterial species both in the community and the hospitals. This may complicate the therapeutic management of infections. Decreased susceptibility to fluoroquinolones arises mainly by singlestep mutations in the gyrA and parC genes, which encode the fluoroquinolones targets, the topoisomerase enzymes, conferring cross resistance to all fluoroquinolones. Accumulation of multiple mutations in several genes confers increasing level of resistance associated with clinical failure. However, even low level resistance can generate therapeutic failure. In 1998, some mobile elements with a potential for the horizontal transfer of the quinolone resistance genes were described. The loci which are responsible for this plasmid-mediated quinolone resistance, which have been designated as qnrA, qnrB and qnrS, have been identified in the Enterobacteriaceae species. Aim: To evaluate the susceptibility pattern of the isolates to various antibiotics and to know the prevalence rate of ciprofloxacin resistance in our hospital. Materials & Methods: A total of 916 gram-negative bacilli (GNB) were isolated from different clinical specimens over a period of nine months, were subjected to antibiotic susceptibility testing. Isolates with resistance or with a decreased susceptibility to ciprofloxacin (£20 mm) were then screened for their minimum inhibitory concentration(MIC) by using the E-test. Results: Out of 916 GNB, 321 (35%) isolates were resistant to ciprofloxacin. The MIC of these isolates ranged from 4 to >32?g/ml.Conclusion: The resistance rate to ciprofloxacin was 35% in our study. Most of the ciprofloxacin resistant isolates were from urinary tract infections (UTI). The ciprofloxacin resistance was also closely associated with multi-drug resistance, thus limiting the treatment options. Ciprofloxacin resistance can be used as a general surrogate marker of multidrug resistance, thus limiting the already restricted treatment options. The considerably high MIC values for ciprofloxacin in this study reflected the extent of the treatment problems for these resistant isolates and a need for the continuous evaluation of the commonly used antibiotics. DOI: http://dx.doi.org/10.3329/bjms.v11i4.12604 Bangladesh Journal of Medical Science Vol. 11 No. 04 Oct’12

Antibacterial resistances in uncomplicated urinary tract infections in women: ECO·SENS II data from primary health care in Austria

BackgroundUncomplicated urinary tract infections (UTI) are a frequent reason for consultation of women in primary health care. To avoid therapy failure and development of resistances, the choice of an antibiotic should be based on the knowledge of recent local resistance data but these data are scarce for the Austrian primary health care sector. Within the context of the ECO·SENS II study it was the aim to obtain appropriate and relevant local resistance data and describe the changes in the resistance pattern in comparison to the ECO·SENS study.Methods23 GPs from different parts of Austria participated in the study between July 2007 and November 2008. According to the defined inclusion- and exclusion criteria female patients with symptoms of an uncomplicated UTI were included and a midstream urine sample was collected. In case of significant bacteriuria susceptibility testing of E. coli against 14 antibiotics was performed. Descriptive statistical methods were used.ResultsIn 313 patients included in the study, a total of 147 E. coli isolates (47%) were detected and tested. The resistance rates were in %: Mecillinam (0.0), nitrofurantoin (0.7), fosfomycin trometamol (0.7), gentamycin (1.4), cefotaxime (2.7), ceftazidime (2.7), Cephadroxil (4.1) and ciprofloxacin (4.1). Higher resistance rates were found in amoxicillin/clavulanic acid (8.9), nalidixic acid (9.6), trimethoprim/sulphamethoxazole (14.4), trimethoprim (15.8), sulphamethoxazole (21.2) and ampicillin (28.8). Additionally, the comparison of these results with the results of the ECO·SENS study demonstrated an increase in resistance rates of ampicillin, amoxicillin/clavulanic acid, nalidixic acid and ciprofloxacin.ConclusionsThe resistance data for E. coli in uncomplicated UTIs in women gained by this study are the most recent data for this disease in Austria at the moment. The increased resistance rates of amoxicillin/clavulanic acid, ciprofloxacin and nalidixic acid should be respected when choosing an appropriate antibiotic for uncomplicated UTIs. The use of ampicillin, sulphamethoxazole, trimethoprim and trimethoprim/sulphametoxazole in uncomplicated UTIs in women should be questioned at all. The findings of this study should result in a regular surveillance system of resistances emerging in the ambulatory sector designed after the model of the EARS-Net.

Emergence and spread of B2-ST131-O25b, B2-ST131-O16 and D-ST405 clonal groups among extended-spectrum- -lactamase-producing Escherichia coli in Japan

The increasing prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has been associated with the emergence of the CTX-M-producing sequence type 131 (ST131) pandemic clonal group, a member of the O25b serogroup and the B2 phylogenetic group. To assess the clonal spread of ESBL-producing E. coli in Japan, a regional surveillance programme was conducted. A total of 581 ESBL-producing clinical specimen E. coli isolates were collected between 2001 and 2010. Clonal groups, including ST131, D-ST405, D-ST393 and D-ST69, were determined using the PCR O type, phylogenetic grouping by triplex PCR, allele-specific PCR and multilocus sequence typing (MLST). A subset of clonal groups underwent PFGE. Among clonal strains, 215 isolates (37%) were identified as belonging to the ST131 group, 185 as B2-ST131-O25b (32%), 26 as B2-ST131-O16 (4%), 3 as B1-ST131-O25b (0.5%) and 1 as B2-ST131-O-non-typeable (0.1%). Forty-one isolates (7%) were identified as belonging to the D-ST405 clonal group, seven (1%) as D-ST69 and two (0.3%) as D-ST393. The B2-ST131-O16 clonal group was characterized by CTX-M-14 and a significantly lower ciprofloxacin resistance rate than the B2-ST131-O25b clonal group. The B2-ST131-O16 and B2-ST131-O25b clonal groups each made up a single PFGE cluster, with 65% similarity. The rate of ESBL-producing E. coli increased over the years (0.2% in 2001 to 9.7% in 2010) and corresponded to increases in the numbers of the B2-ST131-O25b, B2-ST131-O16 and D-ST405 clonal groups. The B2-ST131-O25b, B2-ST131-O16 and D-ST405 clonal groups have contributed to the spread of ESBL-producing E. coli in Japan.

Antimicrobial Susceptibility and Distribution of Salmonella spp., Shigella spp., and Vibro parahaemolyticus Isolated from Stool Specimen in a Tertiary Hospital in 2003-2010

Recently, antibiotic resistant salmonellosis is increasing, making it difficult to treat patients with Salmonella infections. This study analyzed the changes in the species, serogroups, and antimicrobial susceptibility of enteric pathogens isolated from stool specimens during the 8 years from 2003 to 2010 in a tertiary hospital. In total, 237 (1.9%) were isolated from 12,289 stool specimens, comprising 50.6% NTS and 49% Vibrio parahaemolyticus. Serogroups D, B, and C Salmonella were isolated most frequently in that order. Of the Salmonella, 49% of the isolates were ampicillin resistant and this rate for serogroups B, C, and D Salmonella was 56.8, 64.7, and 43.5%, respectively. Overall, the rates of trimethoprim-sulfamethoxazole (SXT), chloramphenicol (CM), and ciprofloxacin resistance were 11.0, 22.0, and 0%, respectively. Two cefotaxime-resistant Salmonella were isolated in 2010. All of the V. parahaemolyticus were susceptible to SXT, CM, and tetracycline. In conclusion, NTS and V. parahaemolyticus were the major enteric pathogens isolated from stool during the 8 years examined, and the rate of Salmonella resistance to antimicrobial agents increased significantly. Antimicrobial susceptibility testing is mandatory for the proper treatment of patients with Salmonella spp. infection.

Molecular epidemiology ofPseudomonas aeruginosa in cystic fibrosis patients from Southeast Austria

Pseudomonas aeruginosa is the major pathogen in the cystic fibrosis (CF) lung, the predominant source of its acquisition, however, is under discussion. In order to study the molecular epidemiology, we evaluated 86 P. aeruginosa isolates from 43 CF patients from southeast Austria. The DiversiLab system was used to identify genetic relationships among the isolates. Antibiotic susceptibilities were tested with a broth microdilution method (Micronaut Merlin). A total of 39 unrelated P. aeruginosa genotypes were found of which 34 were unique to a single patient and one was unique to a sibling pair. We found low rates of resistance for β-lactams with resistance to piperacillin/tazobactam and ceftazidime ranging from 4 to 6%. Resistance rates for meropenem and ciprofloxacin were 11% and 15%, respectively. The prevalence of multidrug-resistant isolates was 2%. We conclude that the majority of P. aeruginosa isolates from CF patients originate from environmental sources and patient-to-patient spread is very uncommon in our centre.

Antimicrobial resistance trends in blood culture positive Salmonella Typhi isolates from Pondicherry, India, 2005–2009

Typhoid fever is caused by Salmonella enterica serovar Typhi, a major public health concern in developing countries. Recently, there has been an upsurge in the occurrence of bacterial isolates that are resistant to ciprofloxacin, and the emergence of broad spectrum β-lactamases in typhoidal salmonellae constitutes a new challenge for the clinician. A total of 337 blood culture isolates of S. Typhi, isolated from Pondicherry, India, between January 2005 and December 2009, were investigated using phenotypic, molecular and serological methods. Of the 337 isolates, 74 (22%) were found to be multidrug resistant (MDR) and 264 (78%) nalidixic acid resistant (NAR). Isolates with reduced susceptibility to ciprofloxacin possessed single mutations in the gyrA gene. A high rate of resistance (8%) was found to ciprofloxacin. All isolates with a ciprofloxacin MIC ≥ 4 mg/L possessed both double mutations in the QRDR of the gyrA gene and a single mutation in the parC gene. Active efflux pump mechanisms were also found to be involved in ciprofloxacin resistance. Finally, a large number of PFGE patterns (non-clonal genotypes) were observed among the S. Typhi isolates. In conclusion, a high rate of ciprofloxacin resistance was observed in comparison to other endemic areas in blood culture isolates of S. Typhi from Pondicherry, India, with steadily increasing NAR but decreasing MDR isolations over the study period. This is most likely to be due to an increased use of ciprofloxacin as a first-line drug of choice over more traditional antimicrobial agents for the treatment of typhoid fever.

Genetic basis of cefotaxime resistant isolates of Klebsiella pneumoniae from Cairo

Resistance rate of uropathogenic Escherichia coli against different antimicrobial agents is currently a matter of concern. The antimicrobial susceptibility patterns of 100 uropathogenicE. coli isolated from Saudi Arabia was conducted by broth microdilution method. The resistance genes for chloramphenicol, tetracycline, sulphamethoxazole and streptomycinwere checked by polymerase chain reaction (PCR). The overall resistance for sulphamethoxazole and streptomycin was 100%. However, the resistance rates for ampicillin, tetracycline, chloramphenicol, trimethoprim, sulphamethoxazole/trimethoprim, amoxicillin/clavulanate, gentamicin, amikacin, ciprofloxacin, cefotaxime, ceftazidime, aztreonam, cefepime and nitrofurantoin were 90, 85, 83, 70, 62, 60, 42, 29, 24, 22, 21, 20, 17 and 5% respectively. All isolates were sensitive to imipenem, tigecycline and cefoxitin. The prevalence of the antibiotic resistance genes for strA + strB, tet(B), catI, sul2, aadA, sul1, cmlA, tet(D) and sul3 were 100, 94.5, 89.5, 86.36, 77.3, 68.18, 45, 13.6 and 5.5% respectively. The catI, tet(B), and sul2 genes were the most prevalent resistance genes. The prevalence of class 1 integrase was 95.45%. The present study gives baseline data on molecular basis of antimicrobial resistance in uropathogenic E. coli from Riyadh. In the majority of cases, resistance to a given antimicrobial was caused by more than single gene. Keywords: Escherichia coli, urinary tract infections, antimicrobial resistances, Saudi Arabia.

Molecular resistance mechanisms to older antimicrobial agents in Eschericia coli isolates

Resistance rate of uropathogenic Escherichia coli against different antimicrobial agents is currently a matter of concern. The antimicrobial susceptibility patterns of 100 uropathogenicE. coli isolated from Saudi Arabia was conducted by broth microdilution method. The resistance genes for chloramphenicol, tetracycline, sulphamethoxazole and streptomycinwere checked by polymerase chain reaction (PCR). The overall resistance for sulphamethoxazole and streptomycin was 100%. However, the resistance rates for ampicillin, tetracycline, chloramphenicol, trimethoprim, sulphamethoxazole/trimethoprim, amoxicillin/clavulanate, gentamicin, amikacin, ciprofloxacin, cefotaxime, ceftazidime, aztreonam, cefepime and nitrofurantoin were 90, 85, 83, 70, 62, 60, 42, 29, 24, 22, 21, 20, 17 and 5% respectively. All isolates were sensitive to imipenem, tigecycline and cefoxitin. The prevalence of the antibiotic resistance genes for strA + strB, tet(B), catI, sul2, aadA, sul1, cmlA, tet(D) and sul3 were 100, 94.5, 89.5, 86.36, 77.3, 68.18, 45, 13.6 and 5.5% respectively. The catI, tet(B), and sul2 genes were the most prevalent resistance genes. The prevalence of class 1 integrase was 95.45%. The present study gives baseline data on molecular basis of antimicrobial resistance in uropathogenic E. coli from Riyadh. In the majority of cases, resistance to a given antimicrobial was caused by more than single gene. Keywords: Escherichia coli, urinary tract infections, antimicrobial resistances, Saudi Arabia.

A Korean Nationwide Surveillance Study for Non-TyphoidalSalmonellaIsolated in Humans and Food Animals from 2006 to 2008: Extended-Spectrum β-Lactamase, Plasmid-Mediated AmpC β-Lactamase, and Plasmid-Mediated Quinolone ResistanceqnrGenes

Background The emergence of non-typhoidal Salmonella (NTS) with decreased susceptibilities to fluoroquinolone, ampicillin, or ceftriaxone has been reported worldwide. However, current surveillance studies of resistance among NTS in Korea are limited. Thus, the antimicrobial susceptibilities; resistance mechanisms such as extended-spectrum β-lactamase (ESBL), plasmid-mediated AmpC β-lactamase (PABL), and plasmid-mediated quinolone resistance (PMQR); and molecular epidemiologic characteristics were investigated in the present study. Methods National Institute of Health and National Veterinary Research and Quarantine Service collected NTS strains from 219 clinical and 293 non-clinical specimens from 2006 to 2008. The antimicrobial susceptibilities were determined using the Clinical and Laboratory Standards Institute disk diffusion test. ESBL, PABL, and qnr genotyping were performed using PCR and nucleotide sequencing. Pulsed-field gel electrophoresis was used for the molecular epidemiologic study. Results The resistance to ampicillin in clinical and non-clinical NTS was 49% and 18 to 47%, respectively. The resistance rates to trimethoprim-sulfamethoxazole in clinical and non-clinical NTS were 8% and 0 to 41%, respectively. The rates to extended-spectrum cephalosporin were 0 to 1%. One CTX-M-15-producing isolate and four CMY-2-producing isolates were detected. Notably, PFGE analysis showed four isolates carrying blaCMY-2, including one non-clinical strain had high clonality. Although the rate of ciprofloxacin resistance was very low, two qnrS1-carrying NTS strains were detected in non-clinical specimens. Conclusion The resistance rates to ampicillin in both clinical and non-clinical NTS were high, while those to trimethoprim-sulfamethoxazole varied depending on the specimen. NTS strains harboring CTX-M-15-type ESBL or CMY-2-type PABL were detected even though the resistance rates to cephalosporins were very low. Four NTS strains carrying the blaCMY-2-gene implied zoonotic infection. Continuous effort to minimize transfer of resistance genes in NTS is necessary.

Characteristics of CTX-M ESBL-producing Escherichia coli isolates from the Lao People's Democratic Republic, 2004-09

Characteristics of CTX-M ESBL-producing Escherichia coli isolates from the Lao People's Democratic Republic, 2004-09

The changing pattern of antimicrobial resistance within 42 033 Escherichia coli isolates from nosocomial, community and urology patient‐specific urinary tract infections, Dublin, 1999–2009

To investigate the changing pattern of antimicrobial resistance in Escherichia coli urinary tract infection over an eleven year period, and to determine whether E. coli antibiotic resistance rates vary depending on whether the UTI represents a nosocomial, community acquired or urology patient specific infection. A retrospective analysis of the 42,033 E. coli urine isolates from the 11-year period 1999-2009 in a single Dublin teaching hospital was performed. WHONET(TM) software was used to analyse the changing pattern of sensitivity and resistance of E. coli to commonly used antibiotics over the study period. The origins of the urine samples were stratified into three groups: inpatients with nosocomial UTIs; urine originating from the emergency department and general practice (community UTIs); and UTIs in urology patients. Urinary tract infections in the urology patient population demonstrate higher antibiotic resistance rates than nosocomial or community UTIs. There were significant trends of increasing resistance over the 11-year period for ampicillin, trimethoprim, gentamicin and ciprofloxacin, and significant differences in co-amoxyclav, gentamicin, nitrofurantion and ciprofloxacin resistance rates depending on the sample origin. Ampicillin and trimethoprim were the least active agents against E. coli, with total 11-year resistance rates of 58.3 and 33.8%, respectively. The overall gentamicin resistance rate was 3.4% and is climbing at a rate of 0.7% per year (P < 0.001). Within the urology patient population the resistance rate was 6.4%. Ciprofloxacin resistance approaches 20% in the nosocomial UTI population and approaches 30% in the urology population; however, it remains a reasonable empirical antibiotic choice in this community, with an 11-year resistance rate of 10.6%. E. coli remains the commonest infecting uropathogen in the community and hospital setting with its incidence climbing from 50 to 60% of UTIs over the 11-year period. Neither penicillins nor trimethoprim represent suitable empirical antimicrobials for UTI and ciprofloxacin resistance in this Dublin-based study renders it unsuitable empirical therapy for nosocomial UTIs and UTIs in the urology population. The dramatic 11-year rate increase in gentamicin resistance is of paramount concern.

Cranberries vs Antibiotics to Prevent Urinary Tract Infections

The increasing prevalence of uropathogens resistant to antimicrobial agents has stimulated interest in cranberries to prevent recurrent urinary tract infections (UTIs). In a double-blind, double-dummy noninferiority trial, 221 premenopausal women with recurrent UTIs were randomized to 12-month prophylaxis use of trimethoprim-sulfamethoxazole (TMP-SMX), 480 mg once daily, or cranberry capsules, 500 mg twice daily. Primary end points were the mean number of symptomatic UTIs over 12 months, the proportion of patients with at least 1 symptomatic UTI, the median time to first UTI, and development of antibiotic resistance in indigenous Escherichia coli. After 12 months, the mean number of patients with at least 1 symptomatic UTI was higher in the cranberry than in the TMP-SMX group (4.0 vs 1.8; P = .02), and the proportion of patients with at least 1 symptomatic UTI was higher in the cranberry than in the TMP-SMX group (78.2% vs 71.1%). Median time to the first symptomatic UTI was 4 months for the cranberry and 8 months for the TMP-SMX group. After 1 month, in the cranberry group, 23.7% of fecal and 28.1% of asymptomatic bacteriuria E coli isolates were TMP-SMX resistant, whereas in the TMP-SMX group, 86.3% of fecal and 90.5% of asymptomatic bacteriuria E coli isolates were TMP-SMX resistant. Similarly, we found increased resistance rates for trimethoprim, amoxicillin, and ciprofloxacin in these E coli isolates after 1 month in the TMP-SMX group. After discontinuation of TMP-SMX, resistance reached baseline levels after 3 months. Antibiotic resistance did not increase in the cranberry group. Cranberries and TMP-SMX were equally well tolerated. In premenopausal women, TMP-SMX, 480 mg once daily, is more effective than cranberry capsules, 500 mg twice daily, to prevent recurrent UTIs, at the expense of emerging antibiotic resistance. isrctn.org Identifier: ISRCTN50717094.

Fluoroquinolone resistance in Escherichia coli and Klebsiella pneumoniae over 18 years: effect of different systems for eliminating duplicates

Sir, The increase in resistance of Gram-negative bacilli is a serious public health problem and our aim was to determine the effect of different duplicate elimination criteria on the evolution of fluoroquinolone resistance in Escherichia coli and Klebsiella pneumoniae in our setting over a period of 18 years. The criteria used are described in Figure 1. Antibiotic susceptibility was studied using microdilution with the Wider semiautomatic system (Soria Melguizo, Spain) and Etest (AB Biodisk, Solna, Sweden), following CLSI (formerly NCCLS) recommendations. In E. coli, the mean percentage of fluoroquinolone-resistant strains according to the EARS-Net criterion was greater than that detected using the CLSI criterion, both when the total number of strains and when the number of extended-spectrum b-lactamase (ESBL)-producing strains was considered (28.4% versus 22.4% and 65.2% versus 60.5%, respectively). With regard to K. pneumoniae, we obtained 7.2% versus 6.3% and 52.2% versus 40.0%. Analysis of the criterion of time showed that when the period considered for elimination of duplicates increased, the ciprofloxacin resistance rate also increased compared with the CLSI criterion. When the EARS-Net criterion was applied, the prevalence of these microorganisms increased in both hospitalized and non-hospitalized patients, although this phenomenon was more important in the former than in the latter. All data are shown in Table 1. The increase in fluoroquinolone resistance is a serious public health problem, especially in ESBL-producing strains, for which the therapeutic options are far more limited, and the local epidemiology of resistance has been considered a key tool in the control of this process. It is essential to apply a duplicate elimination criterion, since analysis of the data based on the total criterion does not reflect the real situation of resistance. What has not yet been definitively established is which criterion is the best to use in each case. The first isolate from each patient is an objective criterion, but has serious limitations since the same patient may frequently be infected by different strains of the same species during the course of their disease and hospital stay, or a strain may become resistant during treatment of the patient due to the selection of resistant mutants during antibiotic therapy. The EARS-Net criterion reflects more faithfully the real situation of resistance, but suggests that it is necessary to apply strict quality control in phenotypic microbiological studies to detect resistance. Our study suggests that the new EARS-Net method of studying duplicates should be applied in order to detect changes in resistance patterns that may occur during the course of disease due to mutations of the microorganism causing the infection or superinfections by more resistant microorganisms.

Comparison of CTX-M-14- and CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates from patients with bacteremia

Recently, CTX-M-15-producing Enterobacteriaceae has disseminated worldwide. To better understand the success of CTX-M-15-type extended-spectrum β-lactamase, we compared the CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates with CTX-M-14-producing E. coli and K. pneumoniae isolates that had been more prevalent before the recent increase of CTX-M-15 in Korea. Eighty-nine CTX-M-producing E. coli bloodstream infection isolates and 33 K. pneumoniae bloodstream infection isolates were collected in 2008 from nine hospitals in Korea. In vitro susceptibility testing and multilocus sequence typing were performed for all isolates. Phylogenetic groupings and distribution of virulence determinants and addiction systems were examined for only E. coli isolates. Among the 89 CTX-M-producing E. coli isolates, 54 isolates (60.7%) contained bla(CTx-M-15) and bla(CTx-M-14) was identified in 31 isolates (34.8%). Among 33 CTX-M-producing K. pneumoniae isolates, bla(CTx-M-14) and bla(CTx-M-15) were identified in 18 (54.5%) and 15 (45.5%) isolates, respectively. While CTX-M-14- and CTX-M-15-producing E. coli isolates displayed similar antimicrobial resistance rates, CTX-M-15-producing K. pneumoniae isolates showed significantly higher resistance rates of ciprofloxacin and piperacillin-tazobactam than CTX-M-14-producing isolates. ST131 and ST405 were the main clones in both CTX-M-14- and CTX-M-15-producing E. coli isolates. Although the frequency of virulence determinants was similar between two E. coli groups, ST131 and ST405 isolates producing CTX-M-15 showed higher frequency of determinants. In addition, CTX-M-15-producing E. coli isolates showed higher prevalence of addiction systems, particularly vagCD. ST405 showed the highest prevalence rates among main E. coli clones. In K. pneumoniae, ST15 and ST11, with high resistance rates, were the main clones of CTX-M-15-producing isolates, but no main clones was found among CTX-M-14-producing isolates because of extreme diversity. Rapid increase of CTX-M-15-producing E. coli isolates was due to certain clone with high frequency of virulence determinants and addiction systems. High antimicrobial resistance rates of CTX-M-15-producing K. pneumoniae isolates may contribute to their increase.

1365 THE CHANGING PATTERN OF ANTIMICROBIAL RESISTANCE WITHIN 42033 ESCHERICHIA COLI ISOLATES FROM NOSOCOMIAL, COMMUNITY, AND UROLOGY PATIENT SPECIFIC URINARY TRACT INFECTIONS, DUBLIN 1999–2009

You have accessJournal of UrologyInfections/Inflammation of the Genitourinary Tract: Kidney & Bladder1 Apr 20111365 THE CHANGING PATTERN OF ANTIMICROBIAL RESISTANCE WITHIN 42033 ESCHERICHIA COLI ISOLATES FROM NOSOCOMIAL, COMMUNITY, AND UROLOGY PATIENT SPECIFIC URINARY TRACT INFECTIONS, DUBLIN 1999–2009 Ivor Cullen, Rustom Manecksha, McCullagh Eddie, Ted McDermott, Robert Flynn, Philip Murphy, Ron Grainger, John Thornhill, and Jerome Fennell Ivor CullenIvor Cullen Dublin, Ireland More articles by this author , Rustom ManeckshaRustom Manecksha Dublin, Ireland More articles by this author , McCullagh EddieMcCullagh Eddie Dublin, Ireland More articles by this author , Ted McDermottTed McDermott Dublin, Ireland More articles by this author , Robert FlynnRobert Flynn Dublin, Ireland More articles by this author , Philip MurphyPhilip Murphy Dublin, Ireland More articles by this author , Ron GraingerRon Grainger Dublin, Ireland More articles by this author , John ThornhillJohn Thornhill Dublin, Ireland More articles by this author , and Jerome FennellJerome Fennell Dublin, Ireland More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1189AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Escherichia coli (E.Coli) is the most common uropathogen in community and nosocomial urinary tract infection (UTI). Knowledge of local antimicrobial resistance patterns is essential for evidence based empirical antibiotic prescribing. A cut off point of 20% has been suggested as the level of resistance at which an agent should no longer be used empirically. Resistance rates vary depending on whether the sample represents a nosocomial, community acquired or urology patient specific UTI. METHODS A retrospective analysis of the 42033 E.Coli urine isolates from the eleven-year period 1999 to 2009 in a single Dublin teaching hospital was performed. WHONET™ software was used to analyse the changing pattern of sensitivity and resistance of E.Coli to commonly used antibiotics over the study period. The origins of the urine samples were stratified into three groups - inpatients with nosocomial UTIs, urines originating from the emergency department and general practice (community UTIs), and UTIs in urology patients. RESULTS Ampicillin and trimethoprim were the least active agents against E.Coli with total eleven-year resistance rates of 58.3% and 33.8% respectively. The overall gentamicin resistance rate was 3.4% and is climbing at a rate of 0.7% per year (p<0.0001). Within the urology sample population the rate of resistance was 6.4%. Significant trends of increasing resistance over the eleven-year period were identified for ampicillin, trimethoprim, gentamicin and ciprofloxacin. Significant differences were demonstrated in co-amoxyclav, gentamicin, nitrofurantion and ciprofloxacin resistance rates depending on the sample origin. Ciprofloxacin resistance approaches 20% in the nosocomial UTI population and approaches 30% in the urology population. It remains reasonable empirical antibiotic choice in this community with eleven-year resistance of 10.6%. UTIs in the urology patient population demonstrate higher antibiotic resistance rates than nosocomial or community UTIs. CONCLUSIONS E.coli remains the commonest infecting uropathogen in the community and hospital setting with its incidence climbing from 50% to 60% of UTIs over the eleven-year period. Penicillins and trimethoprim are unsuitable empirical antimicrobials for UTI. Ciprofloxacin resistance in this Dublin based study renders it unsuitable empirical therapy for nosocomial UTI and UTI in the urology population. The dramatic eleven-year rate increase in gentamicin resistance is of paramount concern. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e545 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ivor Cullen Dublin, Ireland More articles by this author Rustom Manecksha Dublin, Ireland More articles by this author McCullagh Eddie Dublin, Ireland More articles by this author Ted McDermott Dublin, Ireland More articles by this author Robert Flynn Dublin, Ireland More articles by this author Philip Murphy Dublin, Ireland More articles by this author Ron Grainger Dublin, Ireland More articles by this author John Thornhill Dublin, Ireland More articles by this author Jerome Fennell Dublin, Ireland More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Changing trends in antimicrobial resistance of major bacterial pathogens, 1985–2005: A study from a medical center in northern Taiwan

Antimicrobial resistance is a major health problem worldwide. We evaluated the antimicrobial resistance trends of 16 major bacterial pathogens at a tertiary medical center in northern Taiwan. We conducted a retrospective review of annual summary documents for antimicrobial susceptibility of clinically isolated gram-positive and gram-negative bacteria from 1985 to 2005. The numbers of isolates and susceptibilities were calculated for three 7-year periods: first period, 1985-1991; second period, 1992-1998; and the third period, 1999-2005. During the 21-year period, 219,715 bacterial pathogens were identified. A significant increase in incidence over time was found for methicillin-resistant Staphylococcus aureus, methicillin-resistant S epidermidis, penicillin-nonsusceptible Streptococcus pneumoniae, erythromycin-resistant S pneumoniae, vancomycin-resistant enterococci, cefotaxime/ceftriaxone-resistant Escherichia coli and Klebsiella pneumoniae, and imipenem-resistant Acinetobacter baumannii. Additionally, a significant increase in ciprofloxacin resistance rates over time from 1996 to 2005 was noted for E coli, Enterobacter cloacae, and A baumannii (through 1997 to 2005). However, a significant decrease in erythromycin resistance rate with time from 1999 to 2005 was found for Groups A and B streptococci, non-A, B, D streptococci, and S pneumoniae. Resistance to antimicrobial agents increased rapidly in the past two decades in Taiwan and has become very common in major bacterial pathogens. Continuous enforcement of policies to limit use of antimicrobial agents and active surveillance of antimicrobial resistance through a nationwide system are both warranted.

Differential patterns of antimicrobial resistance in population subsets of Escherichia coli isolated from waste- and surface waters

The species Escherichia coli comprises different subgroups with distinct phylogeny, physiology and ecology and, thus, presumably, with different roles in antimicrobial resistance dissemination. E. coli strains isolated from raw and treated municipal wastewater and from urban water streams were characterized in terms of phylogenetic groups, antimicrobial resistance patterns and the presence of class 1 and class 2 integrons. Our main objective was to investigate the contribution of the different phylo-groups in antimicrobial resistance dissemination in urban waters. Groups A and B1 were predominant in all types of water, evidencing, respectively, the lowest and the highest resistance prevalence. Municipal wastewater treatment was accompanied by significant increases of ciprofloxacin and streptomycin resistance (p < 0.01). Antimicrobial resistance prevalence differed significantly between the different phylo-groups and within the same group, mainly in group A. Such differences contributed to explain the higher ciprofloxacin and streptomycin resistance rates observed in treated effluent in comparison with the raw wastewater. We conclude that the dynamics of the bacterial populations has a major role on the dissemination of antimicrobial resistance in the environment.

Impact of discordant empirical therapy on outcome of community-acquired bacteremic acute pyelonephritis

As ciprofloxacin resistance rate of Escherichia coli causing urinary tract infections has been increasing, concern about inappropriate empirical therapy has been arisen. We performed a retrospective cohort study to determine the impact of discordant empirical antimicrobial therapy on outcome of community-acquired bacteremic acute pyelonephritis. Among a total of 164 cases included, ciprofloxacin was empirically used in 80.5%. The most frequent etiologic organism was E. coli (92.1%), of which 20.5% was resistant to ciprofloxacin. Discordant empirical therapy was documented in 29 cases, which included 25 cases caused by ciprofloxacin-resistant E. coli. Discordant therapy resulted in lower early clinical response rate (34.5% vs. 82.2%; P < 0.001) and longer hospital stay (13.3 days vs. 8.7 days; P = 0.002) compared to concordant therapy. However, overall mortality and clinical cure rate did not differ between two groups. Multivariate analyses showed that worse early clinical response was associated with discordant empirical therapy (OR, 11.08; 95% CI, 4.37-28.07) and presentation with septic shock (OR, 8.52; 95% CI, 1.75-41.49). Longer hospital stay was also associated with discordant empirical therapy (OR, 2.47; 95% CI, 1.04-5.84). Discordant empirical therapy, mostly with ciprofloxacin, leads to worse early clinical response and longer hospital stay than concordant therapy in community-acquired bacteremic acute pyelonephritis, although it does not affect on overall mortality or clinical cure rate.

National Surveillance of Antimicrobial Susceptibility of CTX-M-positive and -Negative Clinical Isolates of Escherichia coli from Kuwait Government Hospitals

Antibiotic resistance in Escherichia coli is becoming a complex therapeutic problem. Surveillance programs are valuable tools and offer important information on bacterial resistance trends. This study was undertaken to determine the susceptibility of clinically significant isolates of E. coli obtained from patients admitted to 8 Kuwait government hospitals and to examine how this was influenced by the production of CTX-M extended-spectrum β-lactamases (ESBLs). The susceptibility of 876 consecutive clinically significant strains of E. coli to 13 antibiotics was determined by Etest. ESBL production was assessed by ESBL-Etest method and the presence of CTX-M β-lactamases was confirmed by PCR technique. Of the 876 isolates, 604 (69%) were highly non-susceptible to ampicillin with MIC90 of >256 μg/ml. Resistance to the 3rd-generation cephalosporins ranged from 7.5% in the maternity hospital to 29% in the Ibn Sina hospital; ciprofloxacin resistance rates ranged from 14% and 40%, respectively. Carbapenems and amikacin demonstrated excellent activity. The minimum inhibitory concentrations (MIC90) of cefotaxime, ceftazidime, cefepime and ciprofloxacin were >256, 64, >256 and >32 μg/ml, respectively for CTX-M-positive isolates versus 0.5, 1, 025 and 0.125 μg/ml for CTX-M-negative strains. Frequencies of CTX-M-positive isolates within the cefotaxime MIC ranges of 1-2, 3-8, 9-16 and >16 μg/ml were 0, 4, 15 and 81%, respectively. In conclusion, the susceptibility of E. coli to the 3rd generation cephalosporins and ciprofloxacin was influenced by the presence of CTX-M ESBL and a high proportion of the CTX-M-producing isolates were in the susceptibility ranges of cefotaxime.