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

Paediatric Escherichia coli urinary tract infection: susceptibility trends and clinical management-a retrospective analysis of a 10-year period

BACKGROUND

Escherichia coli is the predominant urinary pathogen in children. Irish and international studies have demonstrated increasing antimicrobial resistance (AMR) to antibiotics such as co-amoxiclav.

AIMS

We aimed to (1) examine the AMR patterns of paediatric urinary E. coli isolates, from both hospital and community sources, over a 10-year period; (2) assess the effectiveness of Children's Health Ireland (CHI) antimicrobial guidance given local susceptibility data; and (3) review the clinical management of an admitted patient sub-set over a 6-year period.

METHODS

Pure growth of urinary E. coli from patients aged ≤ 14 from 2012 to 2021 were analysed for AMR. Differences in susceptibility rates were assessed. A retrospective chart review conducted on inpatients aged ≥ 2 months to ≤ 14 years, 2016-2021.

RESULTS

E. coli accounted for 70.8% of likely significant positive pure growth cultures (9314 isolates). Susceptibility to co-amoxiclav significantly increased over time, from 66.7% to 80.4% (2016-2021, p < 0.001). Nitrofurantoin and cefalexin had significantly higher susceptibility rates than trimethoprim (< 70% annually). 85.1% of isolates were susceptible to the combination of co-amoxiclav and gentamicin, recommended for those > 2months and systemically unwell. The additional gain in empiric susceptibility provided by gentamicin above that provided by co-amoxiclav alone has fallen from 16.4% to 6.7% (2016-2021). The 222 clinical cases reviewed showed improved antimicrobial guideline compliance over time.

CONCLUSIONS

This study provides important regional AMR data. Co-amoxiclav susceptibility increased significantly over time, contrasting with previous studies. This was temporally associated with stewardship measures reducing co-amoxiclav prescribing. Decreasing utility of gentamicin supports recent CHI guideline updates reducing gentamicin use.

Simplified antibiotic guidelines in urology are associated with decreased multidrug-resistant Enterobacterales

PURPOSE

A simplified therapeutic guideline (STG) was established in our urology ward in 2019 for urinary infections. Our aim was to describe the level of physician adherence to STG and the impact of a limited number of antibiotic compounds on the rate of multidrug-resistant (MDR) bacteria. As guidelines should improve patient care, unfavorable outcomes were also reported.

METHODS

The STG for community-acquired and nosocomial urinary infections, including six antibiotics, was established in November 2019 and has been officially applied since January 2020. Treatment duration has to be ≤14 days. We conducted a before-after study to measure physician adherence to the STG for bacteremia treatment between January 2017 and December 2022. Adherence was defined as exclusive use of STG antibiotics. All isolated bacteria from blood cultures were recorded, including MDR Enterobacterales, defined as AmpC β-lactamase- or ESBL-producing strains. Unfavorable outcomes were defined as uncontrolled infection, a second surgical procedure, ICU requirement, and/or death.

RESULTS

Seventy-six cases of bacteremia occurred between January 2017 and December 2019, and ninety between January 2020 and December 2022. The main comorbid condition was urological cancer (46%). The main reason for surgery was ureteral stent (32%). Antibiotic management in accordance with STG increased from 18% to 52%, p < 0.001, and treatments > 14 days decreased from 53% to 28%, p < 0.001. MDR Enterobacterales bacteremia was reduced from 52% to 35%, p = 0.027. The rate of unfavorable outcomes was unchanged.

CONCLUSION

STG adherence in urology was satisfactory and associated with reduced MDR Enterobacterales bacteremia.

Synergistic Antibacterial Potential of Greenly Synthesized Silver Nanoparticles with Fosfomycin Against Some Nosocomial Bacterial Pathogens

Introduction

A considerable number of morbidities and fatalities occur worldwide as a result of the multidrug resistant microorganisms that cause a high prevalence of nosocomial bacterial infections. Hence, the current investigation was conducted to evaluate the antibacterial potency of green fabricated silver nanoparticles (AgNPs) against four different nosocomial pathogens.

Methods

The flower extract of Hibiscus sabdariffa mediated green fabrication of AgNPs and their physicochemical features were scrutinized using different techniques. Antimicrobial activity of the biogenic AgNPs and their synergistic patterns with fosfomycin antibiotic were evaluated using disk diffusion assay.

Results and Discussion

UV spectral analysis affirmed the successful formation of AgNPs through the detection of broad absorption band at 395 and 524 nm, indicating the surface plasmon resonance of the biofabricated AgNPs. In this setting, the biofabricated AgNPs demonstrated average particle size of 58.682 nm according to transmission electron microscope (TEM) micrographs. The detected hydrodynamic diameter was higher than that noticed by TEM analysis, recording 72.30 nm in diameter and this could be attributed to the action of capping agents, which was confirmed by Fourier Transform Infrared (FT-IR) analysis. Disk diffusion assay indicated the antibacterial potency of biogenic AgNPs (50 μg/disk) against Enterobacter cloacae, Methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli strains with relative inhibition zone diameters of 12.82 ± 0.36 mm, 14.54 ± 0.15 mm, 18.35 ± 0.24 mm and 21.69 ± 0.12 mm, respectively. In addition, E. coli was found to be the most susceptible strain to the biogenic AgNPs. However, the highest synergistic pattern of AgNPs-fosfomycin combination was detected against K. pneumonia strain recording relative synergistic percentage of 64.22%. In conclusion, the detected synergistic efficiency of AgNPs and the antibiotic fosfomycin highlight the potential for utilizing this combination in the biofabrication of effective antibacterial agents against nosocomial pathogens.

Antimicrobial Resistance, Virulence Factor-Encoding Genes, and Biofilm-Forming Ability of Community-Associated Uropathogenic Escherichia coli in Western Saudi Arabia

To explore the prevalence of multidrug-resistant community-associated uropathogenic Escherichia coli (UPEC) and their virulence factors in Western Saudi Arabia. A total of 1,000 urine samples were examined for the presence of E. coli by selective plating on MacConkey, CLED, and sheep blood agar. Antimicrobial susceptibility patterns were determined using Vitek^® 2 Compact (MIC) and the disc diffusion method with Mueller-Hinton agar. Genes encoding virulence factors (kpsMTII, traT, sat, csgA, vat, and iutA) were detected by PCR. The overall prevalence of UTI-associated E. coli was low, and a higher prevalence was detected in samples of female origin. Many of the isolates exhibited resistance to norfloxacin, and 60% of the isolates showed resistance to ampicillin. No resistance to imipenem, meropenem, or ertapenem was detected. In general, half of the isolates showed multiple resistance patterns. UPEC exhibited a weak ability to form biofilms, where no correlation was observed between multidrug resistance and biofilm-forming ability. All uropathogenic E. coli isolates carried the kpsMTII, iutA, traT, and csgA genes, whereas the low number of the isolates harbored the sat and vat genes. The diversity of virulence factors harbored by community-associated UPEC may render them more virulent and further explain the recurrence/relapse cases among community-associated UITs. To the best of our knowledge, this study constitutes the first exploration of virulence, biofilm-forming ability, and its association with multidrug resistance among UPEC isolates in Saudi Arabia. Further investigations are needed to elucidate the epidemiology of community-associated UPEC in Saudi Arabia.

Uropathogens Antimicrobial Sensitivity and Resistance Pattern From Outpatients in Balochistan, Pakistan

Objective To determine the pattern of microbes responsible for urinary tract infections and their susceptibility to different antibiotics. Method This is a cross-sectional study conducted at Quetta, Pakistan. The urine samples of 400 patients were collected and sent for culture and sensitivity analysis. The results were recorded on an excel datasheet. Descriptive statistics were used to describe the data. Results Out of 400 urine samples, 266 samples were culture positive for microorganisms. The most common organism on analysis was Escherichia coli 123/266 (46.24%) followed by Staphylococcus saprophyticus 59/266 (22.18%) and Klebsiella pneumonia 49/266 (18.42%). Gram-negative microorganisms were most susceptible to fosfomycin, cefoperazone/sulbactam, and meropenem. Gram-positive microorganisms were most susceptible to fosfomycin, cefoperazone/sulbactam, meropenem, and amoxicillin/clavulanate. High rates of resistance in E. coli were observed to most commonly prescribed broad-spectrum antibiotics; ceftriaxone (64.35%), cefotaxime (76.54%), ceftazidime (49.43%), cefepime (53.44%), levofloxacin (71.26%), and amoxicillin/clavulanate (70.31%). E. coli was the major multidrug-resistant organism. Conclusion High rates of antibiotic resistance and multi-drug resistance were revealed in this study due to the widespread and injudicious use of broad-spectrum antibiotics. Thus, it is highly recommended to regulate the pharmacies. Physicians should judiciously prescribe antibiotics and practice the culture and sensitivity of urine samples rather than blind prescription. Continued surveillance on uropathogens prevalence and resistance, new and next-generation antibiotics, and rapid diagnostic tests to differentiate viral from bacterial infections is the need of time.

Healthcare-associated urinary tract infections in urology

The purpose of the present review is to report the incidence and characteristics of healthcare-associated urinary tract infections (HAUTIs) in urology with their microbiological and resistance patterns. Urinary tract infections are the main type of healthcare-associated infection in patients hospitalized in a urology ward. Patients admitted to urology departments report a high prevalence of urinary tract catheterization, up to 75% during the hospitalization period, and up to 20% had a urinary catheter before admission. An endourological surgical procedure is another risk factor for HAUTIs. Other risk factors for HAUTIs are the presence of immunosuppression and previous urinary tract infections.

In urological patients, Enterobacterales are the principal causative agent of HAUTIs, and E. coli is the most frequently isolated microorganism. However, there is also a high rate of microorganisms other than E. coli such as Klebsiella spp. and Enterococcus spp. Non-E. coli microorganisms show a higher prevalence in immunosuppressed patients and those with urinary catheters before admission. High resistance patterns are reported in patients with HAUTIs, and ESBL-producing bacteria are frequently described. Moreover, the isolation of multidrug-resistant microorganisms is more common in immunosuppressed patients, those with previous urinary tract infections, and urinary catheters into the upper urinary tract. Treatment must be tailored according to patient characteristics and patient profiles, bearing in mind the ORENUC classification for risk factors (no risk factors (O), recurrent urinary tract infections risk factors (R), extraurogenital risk factors (E), nephropathic disease (N), urological risk factors (U), permanent urinary catheter and non-resolvable urological risk factors (C)).

Recurrent Urinary Tract Infections: Unraveling the Complicated Environment of Uncomplicated rUTIs

Urinary tract infections (UTIs) are frequent in humans, affecting the upper and lower urinary tract. Present diagnosis relies on the positive culture of uropathogenic bacteria from urine and clinical markers of inflammation of the urinary tract. The bladder is constantly challenged by adverse environmental stimuli which influence urinary tract physiology, contributing to a dysbiotic environment. Simultaneously, pathogens are primed by environmental stressors such as antibiotics, favoring recurrent UTIs (rUTIs), resulting in chronic illness. Due to different confounders for UTI onset, a greater understanding of the fundamental environmental mechanisms and microbial ecology of the human urinary tract is required. Such advancements could promote the tandem translation of bench and computational studies for precision treatments and clinical management of UTIs. Therefore, there is an urgent need to understand the ecological interactions of the human urogenital microbial communities which precede rUTIs. This review aims to outline the mechanistic aspects of rUTI ecology underlying dysbiosis between both the human microbiome and host physiology which predisposes humans to rUTIs. By assessing the applications of next generation and systems level methods, we also recommend novel approaches to elucidate the systemic consequences of rUTIs which requires an integrated approach for successful treatment. To this end, we will provide an outlook towards the so-called 'uncomplicated environment of UTIs', a holistic and systems view that applies ecological principles to define patient-specific UTIs. This perspective illustrates the need to withdraw from traditional reductionist perspectives in infection biology and instead, a move towards a systems-view revolving around patient-specific pathophysiology during UTIs.

Current antibiotic resistance patterns of rare uropathogens: survey from Central European Urology Department 2011-2019

BACKGROUND

While the resistance rates of commonly detected uropathogens are well described, those of less frequent Gram-negative uropathogenic bacteria have seldom been reported. The aim of this study was to examine the resistance rates of less frequent uropathogenic Gram-negatives in a population of patients treated in a Department of Urology of a tertiary referral centre in Central Europe over a period of 9 years.

METHODS

Data on all positive urine samples from urological in- and out-patients were extracted form the Department of Clinical Microbiology database from 2011 to 2019. Numbers of susceptible and resistant isolates per year were calculated for these uropathogens: Acinetobacter spp. (n = 74), Citrobacter spp. (n = 60), Enterobacter spp. (n = 250), Morganella morganii (n = 194), Providencia spp. (n = 53), Serratia spp. (n = 82) and Stenotrophomonas maltophilia (n = 27). Antimicrobial agents selected for the survey included: ampicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam; cefuroxime, cefotaxime, ceftazidime and cefepime; ciprofloxacin and ofloxacin; gentamicin and amikacin; ertapenem, meropenem and imipenem; trimethoprim-sulfamethoxazole (co-trimoxazole), nitrofurantoin and colistin.

RESULTS

Penicillin derivatives have generally poor effect except piperacillin/tazobactam. Cefuroxime is not efficient unlike cefotaxime (except against Acinetobacter spp. and S. maltophilia). Susceptibility to fluoroquinolones is limited. Amikacin is somewhat more efficient than gentamicine but susceptibilities for both safely exceed 80%. Nitrofurantoin shows virtually no efficiency. Cotrimoxazole acts well against Citrobacter spp., Serratia spp. and it is the treatment of choice for S. maltophilia UTIs. Among carbapenems, ertapenem was less efficient than meropenem and imipenem except for S. maltophilia whose isolates were mostly not suceptible to any carbapenems.

CONCLUSIONS

Uropathogenic microorganisms covered in this report are noteworthy for their frequently multi-drug resistant phenotypes. Knowledge of resistance patterns helps clinicians choose the right empirical antibiotic treatment when the taxonomical assignment of the isolate is known but sensitivity results are pending.

Current Antibiotic Resistance Trends of Uropathogens in Central Europe: Survey from a Tertiary Hospital Urology Department 2011-2019

Monitoring of pathogen resistance profiles is necessary to guide empirical antibiotic therapy before culture and sensitivity results become available. The aim of this study was to describe current antibiotic resistance patterns of five most frequent causative uropathogens in a Department of Urology of a tertiary referral centre in Central Europe over a period of nine years. The Hospital Department of Clinical Microbiology database was used to extract data on all positive urine samples from inpatients in the Department of Urology between 2011 and 2019. Numbers of susceptible and resistant isolates per year were calculated for five most frequent uropathogens: Escherichia coli, Enterococcus spp., Klebsiella spp., Pseudomonas aeruginosa, and Proteus spp. Antimicrobial agents selected for the survey included: ampicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam; cefuroxime, cefotaxime, ceftazidime and cefepime; ciprofloxacin and ofloxacin; gentamicin and amikacin; ertapenem, meropenem and imipenem; trimethoprim-sulfamethoxazole (co-trimoxazole), nitrofurantoin, colistin, and vancomycin. High resistance rates of Gram-negative uropathogens were demonstrated to most common antimicrobials, with statistically significant increasing or decreasing trends in some cases. No carbapenem-resistant Enterobacteriaceae were isolated. Vancomycin-resistant Enterococcus spp. strains were rare in our population.

A Clinical Perspective on the Antimicrobial Resistance Spectrum of Uropathogens in a Romanian Male Population

Considering urinary tract infections (UTIs), a significant public health problem with negligible recent research, especially on the male eastern European population, we aimed to determine the antimicrobial resistance rates of uropathogens for the most commonly used antibiotics in urological practice in our country. We conducted a multicenter retrospective study in two different teaching hospitals in Romania, analyzing urine samples from 7719 patients to determine the frequency of incriminating pathogens and their resistance to different antibiotics, in a comparative approach. We determined Escherichia coli (35.98%) to be the most common pathogen with the highest sensitivity to amikacin (S = 91.72%), meropenem (S = 97.17%) and fosfomycin (S = 86.60%) and important resistance to amoxicillin-clavulanic ac. (R = 28.03%) and levofloxacin (R = 37.69%), followed by Klebsiella spp. (22.98%) with the highest sensitivity to amikacin (S = 78.04%) and meropenem (S = 81.35%) and important resistance to amoxicillin-clavulanic ac. (R = 65.58%) and levofloxacin (R = 45.36%); the most frequent Gram-positive pathogen was Enterococcus spp. (19.73%) with the highest sensitivity for vancomycin (S = 93.75%) and fosfomycin (S = 87.5%) and considerable resistance to penicillin (R = 33.52%) and levofloxacin (R = 42.04%). The findings are an important tool in managing UTIs and should be acknowledged as reference research not only for clinicians from Romania but for all physicians treating male UTIs.

How can we improve investigation, prevention and treatment for recurrent urinary tract infections - ICI-RS 2018

BACKGROUND

Recurrent urinary tract infection (rUTI) is a chronic condition and has a significant impact on health-related quality of life. The commonly used definition for rUTI is greater than three episodes in a year or more than two in 6 months. Current diagnostic methods have been used worldwide for over five decades, despite well evidenced criticism. Enhanced culture techniques demonstrate that the microbiome of the bladder is far more complex than previously thought and begs a reappraisal of our current testing. Treatment of rUTI is based on a small number of antibiotic trials with some evidence showing a reduction in the number of positive cultures, but one must be cautious in interpreting the results and weigh against the risk of generation of antimicrobial resistance (AMR).

AIM

The International Consultation on Incontinence-Research Society think tank reviewed the literature with a view to improving investigation, prevention and treatment of rUTI.

METHODS

A multidisciplinary team of experts were invited to present evidence regarding the current diagnostic methods, recent advances related to bladder biome mapping and current treatment strategies, including antibiotic and nonantibiotic options. Current guidelines regarding antibiotic stewardship and concerns regarding AMR were discussed.

DISCUSSION

Outcome of the think tank discussions are summarised with a set of recommendations to inform future research. Particular consideration is given to bacterial survival in the bladder after treatment as well as defects in urothelial barrier function which may play a significant part in the failure to eradicate UTI.

Antibiotic resistance of Escherichia coli isolated from uncomplicated UTI in general practice patients over a 10-year period

Recommendations of first choice antibiotic therapy need to be based on actual antibiotic susceptibility data. We determined the antibiotic susceptibility of E. coli in uncomplicated UTI among women and compared the results with 2004 and 2009. In 30 sentinel general practitioner practices of Nivel Primary Care database, urine samples were collected from women with symptoms of uncomplicated UTI. Patient characteristics, E. coli susceptibility, and ESBL production were analyzed. Six hundred eighty-nine urine samples were collected; E. coli was the most isolated uropathogen (83%). Antibiotic susceptibility was stable over time except for ciprofloxacin (96% in 2004, 97% in 2009, and 94% in 2014; P < 0.05). The susceptibility to co-amoxiclav was 88%, 87%, and 92% in 2004, 2009, and 2014, respectively. The prevalence of ESBL-producing E. coli increased from 0.1% in 2004 to 2.2% in 2014 (P < 0.05). Regional differences in antibiotic susceptibility for co-trimoxazole were found being the highest in the west (88%) and the lowest in the north (72%, P = 0.021). Ciprofloxacin susceptibility was related to antibiotic use in the past 3 months (97% no use versus 90% use, P = 0.002) and age > 70 years (P = 0.005). In 2014, prescription of fosfomycin increased compared to 2009 (14.3% versus 5.6%) at the expense of co-amoxiclav, co-trimoxazole, and fluoroquinolones (P < 0.05). The susceptibility percentages to most antimicrobial agents tested were stable over 10 years’ period although the prevalence of E. coli and ESBLs significantly increased. Performance of a survey with regular intervals is warranted.

Impact of Allergy and Resistance on Antibiotic Selection for Recurrent Urinary Tract Infections in Older Women

OBJECTIVES

To review the impact of antibiotic allergy and resistance in older women with recurrent urinary tract infections (RUTIs) as determinants for a suitable oral antibiotic treatment choice.

METHODS

A prospectively maintained database of women 65 years old and older with documented RUTIs (≥3 UTI/y) and trigonitis on cystoscopy was reviewed. Demographic data, known drug allergies, renal function, antibiotic susceptibility of most recent urine culture, allergy, or resistance to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolones, and nitrofurantoin were obtained.

RESULTS

From 2006 to 2014, 86 women with RUTIs met study criteria. Mean age was 77.9 ± 7.8, with 94% being Caucasian. An estimated glomerular filtration rate >30 mL/min was noted in 94%. The percentage of women allergic, resistant, or both allergic and resistant to TMP-SMX was 33%, 29%, and 15%, to fluoroquinolones was 14%, 34%, and 8.1%, or nitrofurantoin was 16%, 14%, and 5%, respectively. Twenty-eight percent (24 of 86) of women who were allergic and/or resistant to TMP-SMX and fluoroquinolones were sensitive to nitrofurantoin. Twenty percent (17 of 86) were allergic and/or resistant to all 3 antibiotics. Women who were allergic or resistant to TMP-SMX had a significantly higher number of other antibiotic resistances compared with women sensitive to TMP-SMX (4.9 ± 3.6 vs 2.1 ± 2.3; P < .0001). Similarly, women with fluoroquinolone allergy or resistance had significantly more antibiotic resistances than those who were fluoroquinolone sensitive (5.8 ± 3.5 vs 2.3 ± 2.5; P < .0001).

CONCLUSION

Because of allergy and/or antibiotic resistance, several first-line antibiotics are not available for many older women with RUTIs. In nearly a third of women, nitrofurantoin was the only viable alternative.

Antibiotic resistance patterns of Escherichia coli urinary isolates and comparison with antibiotic consumption data over 10 years, 2005-2014

INTRODUCTION

Escherichia coli is a common cause of urinary tract infections (UTI). Reviews of antibiotic resistance of this organism can inform choice of empiric treatment of UTI and other infections and strategies for combating antimicrobial resistance. We reviewed laboratory and hospital pharmacy records to assess trends in non-susceptibility rates and the effect of antimicrobial stewardship interventions.

METHODS

A retrospective observational study of isolates of E. coli from MSU samples at a Dublin teaching hospital from inpatients and community, obtained from January 2005 to December 2014. Susceptibility to a panel of antibiotics was determined using the disc diffusion method, as well as extended-spectrum beta-lactamase (ESBL) production status. Trends in resistance were plotted graphically and analysed in a descriptive manner.

RESULTS

Except for nitrofurantoin and gentamicin, non-susceptibility increased for all antimicrobials tested. Co-amoxiclav non-susceptibility reached 48% in hospital and 32.6% in the community by 2014. Piperacillin-tazobactam non-susceptibility increased from 6.8 to 23.8% in hospital and from <1 to 12.5% in community, with similar increases for ESBL producing isolates. Ciprofloxacin non-susceptibility peaked at 25.5% in hospital in 2012 and 11.44% in the community in 2014.

CONCLUSION

Escherichia coli isolates from community MSU samples have high rates of non-susceptibility to trimethoprim and co-amoxiclav. Nitrofurantoin remains the best empiric therapy for cystitis. Increasing non-susceptibility to co-amoxiclav and piperacillin-tazobactam in hospital isolates is concerning. Ciprofloxacin non-susceptibility is increasing faster in the community than in hospital. A sharp reduction in hospital fluoroquinolone consumption did not result in a significant reduction in ciprofloxacin non-susceptibility of hospital E. coli isolates.

Characteristics of gram-negative urinary tract infections caused by extended spectrum beta lactamases: pivmecillinam as a treatment option within South Dublin, Ireland

Background

The prevalence of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is increasing and the therapeutic options are limited, especially in primary care. Recent indications have suggested pivmecillinam to be a suitable option. This pilot study aimed to assess the viability of pivmecillinam as a therapeutic option in a Dublin cohort of mixed community and healthcare origin.

Methods

A prospective measurement of mean and fractional inhibitory concentrations of antibiotic use in 95 patients diagnosed with UTI caused by ESBL-producing Enterobacteriaceae was carried out. 36 % patients were from general practice, 40 % were admitted to hospital within south Dublin, and 25 % samples arose from nursing homes. EUCAST breakpoints were used to determine if an isolate was sensitive or resistant to antibiotic agents.

Results

Sixty-nine percent of patients (N = 66) with urinary ESBL isolates were female. The mean age of females was 66 years compared with a mean age of 74 years for males. Thirty-six percent of isolates originated from primary care, hospital inpatients (26 %), and nursing homes (24 %). The vast majority of ESBL isolates were E. coli (80 %). The E tests for mecillinam and co-amoxiclav had concentration ranges from 0.16 mg/L up to 256 mg/L. The mean inhibitory concentration (MIC) of mecillinam ranged from 0.25 to 256 mg/L, while co-amoxiclav MICs ranged from 6 to 256 mg/L. The percentage of isolates resistant to mecillinam and co-amoxiclav was found to be 5.26 and 94.74 % respectively.

Conclusions

This is the first study exploring the use of pivmecillinam in an Irish cohort and has demonstrated that its use in conjunction with or without co-amoxiclav is an appropriate and useful treatment for urinary tract infections caused by ESBL-producing organisms.

Five-Year Antimicrobial Resistance Patterns of Urinary Escherichia coli at an Australian Tertiary Hospital: Time Series Analyses of Prevalence Data

This study describes the antimicrobial resistance temporal trends and seasonal variation of Escherichia coli (E. coli) urinary tract infections (UTIs) over five years, from 2009 to 2013, and compares prevalence of resistance in hospital- and community-acquired E. coli UTI. A cross sectional study of E. coli UTIs from patients attending a tertiary referral hospital in Canberra, Australia was undertaken. Time series analysis was performed to illustrate resistance trends. Only the first positive E. coli UTI per patient per year was included in the analysis. A total of 15,022 positive cultures from 8724 patients were identified. Results are based on 5333 first E. coli UTIs, from 4732 patients, of which 84.2% were community-acquired. Five-year hospital and community resistance rates were highest for ampicillin (41.9%) and trimethoprim (20.7%). Resistance was lowest for meropenem (0.0%), nitrofurantoin (2.7%), piperacillin-tazobactam (2.9%) and ciprofloxacin (6.5%). Resistance to amoxycillin-clavulanate, cefazolin, gentamicin and piperacillin-tazobactam were significantly higher in hospital- compared to community-acquired UTIs (9.3% versus 6.2%; 15.4% versus 9.7%; 5.2% versus 3.7% and 5.2% versus 2.5%, respectively). Trend analysis showed significant increases in resistance over five years for amoxycillin-clavulanate, trimethoprim, ciprofloxacin, nitrofurantoin, trimethoprim-sulphamethoxazole, cefazolin, ceftriaxone and gentamicin (P<0.05, for all) with seasonal pattern observed for trimethoprim resistance (augmented Dickey-Fuller statistic = 4.136; P = 0.006). An association between ciprofloxacin resistance, cefazolin resistance and ceftriaxone resistance with older age was noted. Given the relatively high resistance rates for ampicillin and trimethoprim, these antimicrobials should be reconsidered for empirical treatment of UTIs in this patient population. Our findings have important implications for UTI treatment based on setting of acquisition.

The economic burden of urinary tract infections in women visiting general practices in France: a cross-sectional survey

Background

Urinary tract infections (UTIs) are among the most common bacterial infections. Despite this burden, there are few studies of the costs of UTIs. The objective of this study was to determine the costs of UTIs in women over 18 years of age who visit general practitioners in France.

Methods

The direct and indirect costs of clinical UTIs were estimated from societal, French National Health Insurance and patient perspectives. The study population was derived from a national cross-sectional survey entitled the Drug-Resistant Urinary Tract Infection (Druti). The Druti included every woman over 18 years of age who presented with symptoms of UTI and was conducted in France in 2012 and 2013 to estimate the annual incidence of UTIs due to antibiotic-resistant Enterobacteriaceae in women visiting general practitioners (GPs) for suspected UTIs.

Results

Of the 538 women included in Druti, 460 were followed over 8 weeks and included in the cost analysis. The mean age of the women was 46 years old. The median cost of care for one episode of a suspected UTI was €38, and the mean cost was €70. The annual societal cost was €58 million, and €29 million of this was reimbursed by the French National Health Insurance system. In 25 % of the cases, the suspected UTIs were associated with negative urine cultures. The societal cost of these suspected UTIs with negative urine cultures was €13.5 million. No significant difference was found between the costs of the UTIs due to antibiotic-resistant E. coli and those due to wild E. coli (p = 0.63).

Conclusion

In the current context in which the care costs are continually increasing, the results of this study suggests that it is possible to decrease the cost of UTIs by reducing the costs of suspected UTIs and unnecessary treatments, as well as limiting the use of non-recommended tests.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1620-2) contains supplementary material, which is available to authorized users.

Cystoscopy and intravesical bacille Calmette-Guérin therapy in antibiotic-naïve patients with bladder cancer with asymptomatic bacteriuria: An update

Urologists often insist on sterile urine before invasive outpatient urological procedures, and urine culture and antibiotics are usually given before cystoscopy or instillation of bacille Calmette–Guérin (BCG) therapy, especially in patients who have positive urine cultures. Our experience suggests that cystoscopy and induction BCG therapy can be performed safely, even in patients with asymptomatic bacteriuria, without pretreatment or prophylactic antibiotics. The rate of subsequent febrile urinary tract infection is <4% in both infected and uninfected patients. Pretreatment antibacterial therapy does not appear to be necessary before these two outpatient urological procedures in patients with bladder cancer. Such strategy facilitates timely interventions and reduces the possibility of antibiotic resistance.

Diagnosis of Urinary Tract Infections in Children

Urinary tract infections (UTIs) are a common occurrence in children. The management and laboratory diagnosis of these infections pose unique challenges that are not encountered in adults. Important factors, such as specimen collection, urinalysis interpretation, culture thresholds, and antimicrobial susceptibility testing, require special consideration in children and will be discussed in detail in the following review.

Risk Factors and Significance of Gentamicin Resistant Positive Urine Culture in Patients Undergoing Urological Surgery: A Short Report

We assessed patients who had pre-operative urine that grew gentamicin-resistant bacteria but were given gentamicin prophylaxis because urine result was not available. Our aim was to identify postoperative-sepsis rates, risk factors to acquire resistant-bacteria, and to optimize our prophylactic regime. Total 4,933 pre-operative urine-samples were reviewed and those positive for E.coli, Klebsiella or Proteus (n = 979) were analysed. Forty-four (4.4%) had gentamicin-resistant bacteria. Of those, 8 were immunosuppressed, 38 (86%) had a recent urological procedure and 29 (66%) had received recent antibiotics. Eighteen (41%) had a urinary catheter and 11 (25%) had double J stent. Three patients (7%) developed post-operative sepsis/febrile urinary tract infection. Although the majority of gentamicin-resistant samples represent colonization, the incidence of post-operative sepsis was significant. Amikacin may be a superior alternative. Our new protocol aims to pre-operatively identify patients at risk of prophylaxis failure with gentamicin and select amikacin as an alternative.

Ciprofloxacin resistance in community- and hospital-acquired Escherichia coli urinary tract infections: a systematic review and meta-analysis of observational studies

Background

During the last decade the resistance rate of urinary Escherichia coli (E. coli) to fluoroquinolones such as ciprofloxacin has increased. Systematic reviews of studies investigating ciprofloxacin resistance in community- and hospital-acquired E. coli urinary tract infections (UTI) are absent. This study systematically reviewed the literature and where appropriate, meta-analysed studies investigating ciprofloxacin resistance in community- and hospital-acquired E. coli UTIs.

Methods

Observational studies published between 2004 and 2014 were identified through Medline, PubMed, Embase, Cochrane, Scopus and Cinahl searches. Overall and sub-group pooled estimates of ciprofloxacin resistance were evaluated using DerSimonian-Laird random-effects models. The I² statistic was calculated to demonstrate the degree of heterogeneity. Risk of bias among included studies was also investigated.

Results

Of the identified 1134 papers, 53 were eligible for inclusion, providing 54 studies for analysis with one paper presenting both community and hospital studies. Compared to the community setting, resistance to ciprofloxacin was significantly higher in the hospital setting (pooled resistance 0.38, 95 % CI 0.36-0.41 versus 0.27, 95 % CI 0.24-0.31 in community-acquired UTIs, P < 0.001). Resistance significantly varied by region and country with the highest resistance observed in developing countries. Similarly, a significant rise in resistance over time was seen in studies reporting on community-acquired E. coli UTI.

Conclusions

Ciprofloxacin resistance in E. coli UTI is increasing and the use of this antimicrobial agent as empirical therapy for UTI should be reconsidered. Policy restrictions on ciprofloxacin use should be enhanced especially in developing countries without current regulations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1282-4) contains supplementary material, which is available to authorized users.

In Vitro Activity of Oral Cephalosporins (Cefprozil and Cefixime) Against Ciprofloxacin-Resistant Enterobacteriaceae from Community-Acquired Urinary-Tract Infections

INTRODUCTION

The global emergence of pathogens of urinary-tract infections resistant to ciprofloxacin or producing extended-spectrum β-lactamases (ESBL) led us to investigate the activity of older antimicrobials such as cefprozil and cefixime against a recent broad collection of urine enterobacteria from 2012 and 2013.

METHODS

Minimum inhibitory concentrations and minimum bactericidal concentrations of cefprozil, cefixime and ciprofloxacin were determined against 293 Escherichia coli (40 ESBL producers), 54 Klebsiella pneumoniae (10 ESBL producers) and 53 Proteus mirabilis isolates.

RESULTS

Cefprozil was more active than ciprofloxacin against non-ESBL-producing E. coli (93.7% vs 80.2%, p < 0.0001); this was not the case for cefixime (85.7% vs 80.2%, p: 0.125). Overall, cefprozil and cefixime inhibited 80-90% of ciprofloxacin-resistant isolates of all studied species. However, they were active against less than 20% of ESBL-producing isolates.

CONCLUSION

Results suggest that cefprozil and cefixime remain a good therapeutic alternative against urine enterobacteria particularly in case of ciprofloxacin-resistant pathogens. Their activity against ESBL-producing pathogens is limited.

Current and potential applications of host-defense peptides and proteins in urology

The use of antibiotics has become increasingly disfavored as more multidrug resistant pathogens are on the rise. A promising alternative to the use of these conventional drugs includes antimicrobial peptides or host-defense peptides. These peptides typically consist of short amino acid chains with a net cationic charge and a substantial portion of hydrophobic residues. They mainly target the bacterial cell membrane but are also capable of translocating through the membrane and target intracellular components, making it difficult for bacteria to gain resistance as multiple essential cellular processes are being targeted. The use of these peptides in the field of biomedical therapies has been examined, and the different approaches to using them under various settings are constantly being discovered. In this review, we discuss the current and potential applications of these host-defense peptides in the field of urology. Besides the use of these peptides as antimicrobial agents, the value of these biological molecules has recently been expanded to their use as antitumor and anti-kidney-stone agents.

Community-associated urinary infections requiring hospitalization: risk factors, microbiological characteristics and patterns of antibiotic resistance

OBJECTIVE

Although patients with urinary tract infections (UTIs) are usually managed as outpatients, a percentage of them requires hospitalization. To review risk factors and microbiological characteristics of community-associated UTIs (CAUTIs) requiring hospitalization has been our objective.

MATERIAL AND METHODS

A prospective observational study was carried out from November 2011 to December 2013. Incidence, microbiological characteristics and antibiotic resistance patterns in patients with CAUTIs that required hospitalization were analyzed. Risk factors (including diabetes mellitus, urolithiasis, urinary catheterization) and resistance rates of each pathogen were also analyzed.

RESULTS

Four hundred and fifty seven patients were hospitalized in our department with CAUTI. The mean age was 56.2±19.85 years. Of them, 52.1% patients were women, 19.7% had urinary indwelling catheter and 11.4% have had a previous UTI. The most frequently isolated pathogens were Escherichia coli (60.6%), followed by Klebsiella (9.2%), Enterococcus (8.4%) and Pseudomonas (7.2%). Enterobacteriaceae other than E.coli were more prevalent in male and older patients. On the other side the most frequently isolated pathogen in patients with a previous UTI and a urinary catheter was Entercoccus. The resistance rates E. coli against ampicillin/amoxicillin + β lactamase inhibitor was 23.5%, against third-generation cephalosporins 16.6%, against fluoroquinolones 31.3% and 16.7% against aminoglycosides. 11.4% E. coli strains were producers of extended-spectrum Beta-lactamases (ESBL). Finally, the resistance rates of Enterococcus and Pseudomonas against quinolones were of 50.0% and 61.5%, respectively.

CONCLUSIONS

CAUTIs that require hospitalization are most frequent in older age, male gender, and presence of urinary catheter, with urolithiasis and with previous episodes of UTI. These factors are also related to isolation of pathogens other than E. coli and higher resistance rates.

Radical prostatectomy in the presence of ongoing refractory ESBL Escherichia coli bacterial prostatitis

A 44-year-old Indian national with a prostate-specific antigen of 5.4 ng/mL underwent 12-core transrectal ultrasound-guided prostate biopsies. Following this, he had three hospital admissions with severe urosepsis secondary to extended spectrum β lactamase (ESBL) producing Escherichia coli. He had recurrent sepsis immediately after discontinuation of intravenous meropenem to which the ESBL was sensitive. He proceeded to radical prostatectomy for intermediate-high risk Gleason 7 prostate cancer, while still on intravenous meropenem, 2 months after his biopsy. His prostatectomy involved a difficult dissection due to inflammatory changes and fibrosis after multiple septic episodes. He had complete resolution of infection after surgery with discontinuation of antibiotics on the third postoperative day, without any recurrence of sepsis.

Clinical microbiology informatics

The clinical microbiology laboratory has responsibilities ranging from characterizing the causative agent in a patient's infection to helping detect global disease outbreaks. All of these processes are increasingly becoming partnered more intimately with informatics. Effective application of informatics tools can increase the accuracy, timeliness, and completeness of microbiology testing while decreasing the laboratory workload, which can lead to optimized laboratory workflow and decreased costs. Informatics is poised to be increasingly relevant in clinical microbiology, with the advent of total laboratory automation, complex instrument interfaces, electronic health records, clinical decision support tools, and the clinical implementation of microbial genome sequencing. This review discusses the diverse informatics aspects that are relevant to the clinical microbiology laboratory, including the following: the microbiology laboratory information system, decision support tools, expert systems, instrument interfaces, total laboratory automation, telemicrobiology, automated image analysis, nucleic acid sequence databases, electronic reporting of infectious agents to public health agencies, and disease outbreak surveillance. The breadth and utility of informatics tools used in clinical microbiology have made them indispensable to contemporary clinical and laboratory practice. Continued advances in technology and development of these informatics tools will further improve patient and public health care in the future.

Factors associated with specific uropathogens in catheter-associated urinary tract infection: Developing a clinical prediction model

Objectives

To identify characteristics associated with particular groups of uropathogens in catheter-associated urinary tract infection (CA–UTI) and to develop clinical prediction rules for identifying these groups.

Methods

Demographic, clinical and microbiological data were analysed from patients with CA–UTI. Infections were categorized into enteric Gram-negative rods, nonfermenters, Gram-positive cocci and fungal. Variables were analysed using univariate and multiple logistic regression analyses, and were used to develop clinical prediction rules.

Results

A total of 492 patients were included in the study. Candida species were the most common uropathogens (30.7%), followed by enterococci (17.3%), Escherichia coli (12.0%), Pseudomonas spp. (10.8%), Klebsiella spp. (7.9%) and staphylococci (6.5%). Clinical prediction rules for the bacterial uropathogenic groups showed poor-to-fair discriminatory power, with sensitivities of <40% and specificities of >90%. However, clinical prediction rules showed good discriminatory power for fungal infections, with a sensitivity of 67.3% and a specificity of 78.1%.

Conclusions

Clinical prediction rules developed for identifying specific groups of bacterial uropathogens in patients with CA–UTI had a low sensitivity, whereas those for fungal infections showed good discriminatory power. Further studies to develop more refined and sensitive tools for predicting specific bacterial uropathogens in CA–UTI are warranted.

Urinary tract infection in small outpatient children: the influence of age and gender on resistance to oral antimicrobials

Urinary tract infection (UTI) is a common bacterial disease in small children in which treatment with antimicrobials is used. The worldwide increase of bacterial resistance to these drugs is threatening the efficacy of such treatment and may increase the risk for long-term damage. The aim of this retrospective study was to analyse the development of resistance to oral antimicrobials over a 10-year period in an unselected outpatient population of small children with first-time UTI. The patient material included 494 boys and 512 girls below 2 years of age with community acquired symptomatic UTI. Escherichia coli bacteria were isolated in 96 % of girls and 89 % of boys (p < 0.0001). The overall resistance of E. coli was 14 % to trimethoprim and below 1 % to cefadroxil and nitrofurantoin. Over the 10-year period, the trimethoprim resistance of E. coli increased from 5 to 17 % but remained unchanged to cefadroxil and nitrofurantoin. E. coli resistance to trimethoprim was related to age: 11 % below and 19 % above 9 months (p < 0.01). The increase in resistance over time and with age was found only in girls.

CONCLUSION

The increasing resistance of E. coli to trimethoprim makes this drug less suitable for empiric treatment of UTI. Young children with UTI seem predisposed to early development of resistance. Therefore, surveillance of resistance to antimicrobials with special regard to age and gender is recommended.

Microbiologic Spectrum and Antibiotic Susceptibility Pattern among Patients with Urinary and Respiratory Tract Infection

Aim. To demonstrate the prevalence of isolated organisms in urinary/respiratory tract infections and their antibiotic susceptibilities in a tertiary care center. Methods and Material. Between January 2008 and January 2010, patients referring to the clinic of cardiology or those admitted to the cardiac wards were enrolled in this cross-sectional descriptive study. Urine and sputum sampling was done for all the patients and the specimens underwent microbiologic examination and, in case of isolation of microorganism, antibiotic disk diffusion test was performed. Results. Escherichia coli (E. coli) was the most prevalent isolated organism in-hospital and community-acquired UTIs and was highly resistant to cephalothin in all the samples followed by cotrimoxazole, and ceftriaxone. It revealed high sensitivity to imipenem, amikacin, and nitrofurantoin. Acinetobacter constituted the most prevalent organism isolated from respiratory secretions and represented the highest resistance to ceftriaxone and the greatest sensitivity to imipenem. Conclusions. E. coli and Acinetobacter remain the most common uropathogenic and respiratory organisms, respectively. However, their increasing resistance to wide-spectrum imipenem, meropenem, and vancomycin is a major concern.

The epidemic of extended-spectrum-β-lactamase-producing Escherichia coli ST131 is driven by a single highly pathogenic subclone, H30-Rx

The Escherichia coli sequence type 131 (ST131) clone is notorious for extraintestinal infections, fluoroquinolone resistance, and extended-spectrum beta-lactamase (ESBL) production, attributable to a CTX-M-15-encoding mobile element. Here, we applied pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing to reconstruct the evolutionary history of the ST131 clone. PFGE-based cluster analyses suggested that both fluoroquinolone resistance and ESBL production had been acquired by multiple ST131 sublineages through independent genetic events. In contrast, the more robust whole-genome-sequence-based phylogenomic analysis revealed that fluoroquinolone resistance was confined almost entirely to a single, rapidly expanding ST131 subclone, designated H30-R. Strikingly, 91% of the CTX-M-15-producing isolates also belonged to a single, well-defined clade nested within H30-R, which was named H30-Rx due to its more extensive resistance. Despite its tight clonal relationship with H30Rx, the CTX-M-15 mobile element was inserted variably in plasmid and chromosomal locations within the H30-Rx genome. Screening of a large collection of recent clinical E. coli isolates both confirmed the global clonal expansion of H30-Rx and revealed its disproportionate association with sepsis (relative risk, 7.5; P < 0.001). Together, these results suggest that the high prevalence of CTX-M-15 production among ST131 isolates is due primarily to the expansion of a single, highly virulent subclone, H30-Rx.

We applied an advanced genomic approach to study the recent evolutionary history of one of the most important Escherichia coli strains in circulation today. This strain, called sequence type 131 (ST131), causes multidrug-resistant bladder, kidney, and bloodstream infections around the world. The rising prevalence of antibiotic resistance in E. coli is making these infections more difficult to treat and is leading to increased mortality. Past studies suggested that many different ST131 strains gained resistance to extended-spectrum cephalosporins independently. In contrast, our research indicates that most extended-spectrum-cephalosporin-resistant ST131 strains belong to a single highly pathogenic subclone, called H30-Rx. The clonal nature of H30-Rx may provide opportunities for vaccine or transmission prevention-based control strategies, which could gain importance as H30-Rx and other extraintestinal pathogenic E. coli subclones become resistant to our best antibiotics.

Resistance patterns of nosocomial urinary tract infections in urology departments: 8-year results of the global prevalence of infections in urology study

OBJECTIVE

To present the worldwide antibiotic resistance rates of uropathogens reported in nosocomial urinary tract infections (NAUTI) during the period of 2003-2010.

MATERIALS AND METHODS

Data from the Global Prevalence Study of Infections in Urology from the period of 2003-2010 were analyzed to evaluate the resistance rates of pathogens causing NAUTI. The web-based application was used to record data of investigators from urology departments participating in the study every year during the days allocated in November. Each center was allowed to enter data on a single day of the study. The point prevalence data was used to find differences among geographic regions and years by utilizing multiple logistic regression analysis.

RESULTS

A total of 19,756 patients were hospitalized during the study period, and in 1,866 of them, NAUTI was reported. Proof of infection was reported in 1,395 patients. Resistance rates of all antibiotics tested other than imipenem against the total bacterial spectrum were higher than 10 % in all regions. Resistance to almost all pathogens was lowest in North Europe, and there is no single year where an outbreak of resistance has been detected.

CONCLUSION

The resistance rates of most of the uropathogens against the antibiotics tested did not show significant trends of increase or decrease with Asia exhibiting the highest rates in general. The only antibiotic tested with an overall resistance rate below 10 % was imipenem. Knowledge of regional and local resistance data and prudent use of antibiotics are necessary to optimize antibiotic therapy in urological patients with NAUTI.

A novel form of bacterial resistance to the action of eukaryotic host defense peptides, the use of a lipid receptor

Host defense peptides show great potential for development as new antimicrobial agents with novel mechanisms of action. However, a small number of resistance mechanisms to their action are known, and here, we report a novel bacterial resistance mechanism mediated by a lipid receptor. Maximin H5 from Bombina maxima bound anionic and zwitterionic membranes with low affinity (Kd > 225 μM) while showing a strong ability to lyse (>55%) and penetrate (π > 6.0 mN m(-1)) these membranes. However, the peptide bound Escherichia coli and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE) membranes with higher affinity (Kd < 65 μM) and showed a very low ability for bilayer lysis (<8%) and partitioning (π > 1.0 mN m(-1)). Increasing levels of membrane DMPE correlated with enhanced binding by the peptide (R(2) = 0.96) but inversely correlated with its lytic ability (R(2) = 0.98). Taken with molecular dynamic simulations, these results suggest that maximin H5 possesses membranolytic activity, primarily involving bilayer insertion of its strongly hydrophobic N-terminal region. However, this region was predicted to form multiple hydrogen bonds with phosphate and ammonium groups within PE head-groups, which in concert with charge-charge interactions anchor the peptide to the surface of E. coli membranes, inhibiting its membranolytic action.

Antibiotic prophylaxis for urinary tract infections after removal of urinary catheter: meta-analysis

OBJECTIVE

To determine whether antibiotic prophylaxis at the time of removal of a urinary catheter reduces the risk of subsequent symptomatic urinary tract infection.:

DESIGN

Systematic review and meta-analysis of studies published before November 2012 identified through PubMed, Embase, Scopus, and the Cochrane Library; conference abstracts for 2006-12 were also reviewed.

INCLUSION CRITERIA

Studies were included if they examined antibiotic prophylaxis administered to prevent symptomatic urinary tract infection after removal of a short term (≤ 14 days) urinary catheter.

RESULTS

Seven controlled studies had symptomatic urinary tract infection after catheter removal as an endpoint; six were randomized controlled trials (five published; one in abstract form) and one was a non-randomized controlled intervention study. Five of these seven studies were in surgical patients. Studies were heterogeneous in the type and duration of antimicrobial prophylaxis and the period of observation. Overall, antibiotic prophylaxis was associated with benefit to the patient, with an absolute reduction in risk of urinary tract infection of 5.8% between intervention and control groups. The risk ratio was 0.45 (95% confidence interval 0.28 to 0.72). The number needed to treat to prevent one urinary tract infection was 17 (12 to 30).

CONCLUSIONS

Patients admitted to hospital who undergo short term urinary catheterization might benefit from antimicrobial prophylaxis when the catheter is removed as they experience fewer subsequent urinary tract infections. Potential disadvantages of more widespread antimicrobial prophylaxis (side effects and cost of antibiotics, development of antimicrobial resistance) might be mitigated by the identification of which patients are most likely to benefit from this approach.

Foodborne urinary tract infections: a new paradigm for antimicrobial-resistant foodborne illness

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. Disproportionately affecting women, UTIs exact a substantial public burden each year in terms of direct medical expenses, decreased quality of life, and lost productivity. Increasing antimicrobial resistance among strains of extraintestinal pathogenic Escherichia coli challenges successful treatment of UTIs. Community-acquired UTIs were long considered sporadic infections, typically caused by the patients' native gastrointestinal microbiota; however, the recent recognition of UTI outbreaks with probable foodborne origins has shifted our understanding of UTI epidemiology. Along with this paradigm shift come new opportunities to disrupt the infection process and possibly quell increasing resistance, including the elimination of non-therapeutic antimicrobial use in food-animal production.

Rapid antimicrobial susceptibility testing by sensitive detection of precursor rRNA using a novel electrochemical biosensing platform

Precursor rRNA (pre-rRNA) is an intermediate stage in the formation of mature rRNA and is a useful marker for cellular metabolism and growth rate. We developed an electrochemical sensor assay for Escherichia coli pre-rRNA involving hybridization of capture and detector probes with tail sections that are spliced away during rRNA maturation. A ternary self-assembled monolayer (SAM) prepared on gold electrode surfaces by coassembly of thiolated capture probes with hexanedithiol and posttreatment with 6-mercapto-1-hexanol minimized the background signal and maximized the signal-to-noise ratio. Inclusion of internal calibration controls allowed accurate estimation of the pre-rRNA copy number per cell. As expected, the ratio of pre-rRNA to mature rRNA was low during stationary phase and high during log phase. Pre-rRNA levels were highly dynamic, ranging from 2 copies per cell during stationary phase to ~1,200 copies per cell within 60 min of inoculation into fresh growth medium. Specificity of the assay for pre-rRNA was validated using rifampin and chloramphenicol, which are known inhibitors of pre-rRNA synthesis and processing, respectively. The DNA gyrase inhibitor, ciprofloxacin, was found to act similarly to rifampin; a decline in pre-rRNA was detectable within 15 min in ciprofloxacin-susceptible bacteria. Assays for pre-rRNA provide insight into cellular metabolism and are promising predictors of antibiotic susceptibility.

Antimicrobial resistance and spread of multi drug resistant Escherichia coli isolates collected from nine urology services in the Euregion Meuse-Rhine

We determined the prevalence and spread of antibiotic resistance and the characteristics of ESBL producing and/or multi drug resistant (MDR) Escherichia coli isolates collected from urine samples from urology services in the Euregio Meuse-Rhine, the border region of the Netherlands (n = 176), Belgium (n = 126) and Germay (n = 119). Significant differences in resistance between the three regions were observed. Amoxicillin-clavulanic acid resistance ranged from 24% in the Netherlands to 39% in Belgium (p = 0.018), from 20% to 40% (p<0.004) for the fluoroquinolones and from 20% to 40% (p = 0.018) for the folate antagonists. Resistance to nitrofurantoin was less than 5%. The prevalence of ESBL producing isolates varied from 2% among the Dutch isolates to 8% among the German ones (p = 0.012) and were mainly CTX-M 15. The prevalence of MDR isolates among the Dutch, German and Belgian isolates was 11%, 17% and 27%, respectively (p< = 0.001 for the Belgian compared with the Dutch isolates). The majority of the MDR and ESBL producing isolates belonged to ST131. This study indicates that most antibiotics used as first choice oral empiric treatment for UTIs (amoxicillin-clavulanic acid, fluoroquinolones and folate antagonists) are not appropriate for this purpose and that MDR strains such as CTX-M producing ST131 have spread in the entire Euregion. Our data stress the importance of ward specific surveillance to optimize empiric treatment. Also, prudent use of antibiotics and further research to alternative agents are warranted.

Resistance surveillance studies: a multifaceted problem--the fluoroquinolone example

INTRODUCTION

This review summarizes data on the fluoroquinolone resistance epidemiology published in the previous 5 years.

MATERIALS AND METHODS

The data reviewed are stratified according to the different prescription patterns by either primary- or tertiary-care givers and by indication. Global surveillance studies demonstrate that fluoroquinolone- resistance rates increased in the past several years in almost all bacterial species except Staphylococcus pneumoniae and Haemophilus influenzae causing community-acquired respiratory tract infections (CARTIs), as well as Enterobacteriaceae causing community-acquired urinary tract infections. Geographically and quantitatively varying fluoroquinolone resistance rates were recorded among Gram-positive and Gram-negative pathogens causing healthcare-associated respiratory tract infections. One- to two-thirds of Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs) were fluoroquinolone resistant too, thus, limiting the fluoroquinolone use in the treatment of community- as well as healthcare-acquired urinary tract and intra-abdominal infections. The remaining ESBL-producing or plasmid-mediated quinolone resistance mechanisms harboring Enterobacteriaceae were low-level quinolone resistant. Furthermore, 10-30 % of H. influenzae and S. pneumoniae causing CARTIs harbored first-step quinolone resistance determining region (QRDR) mutations. These mutants pass susceptibility testing unnoticed and are primed to acquire high-level fluoroquinolone resistance rapidly, thus, putting the patient at risk. The continued increase in fluoroquinolone resistance affects patient management and necessitates changes in some current guidelines for the treatment of intra-abdominal infections or even precludes the use of fluoroquinolones in certain indications like gonorrhea and pelvic inflammatory diseases in those geographic areas in which fluoroquinolone resistance rates and/or ESBL production is high. Fluoroquinolone resistance has been selected among the commensal flora colonizing the gut, nose, oropharynx, and skin, so that horizontal gene transfer between the commensal flora and the offending pathogen as well as inter- and intraspecies recombinations contribute to the emergence and spread of fluoroquinolone resistance among pathogenic streptococci. Although interspecies recombinations are not yet the major cause for the emergence of fluoroquinolone resistance, its existence indicates that a large reservoir of fluoroquinolone resistance exists. Thus, a scenario resembling that of a worldwide spread of β-lactam resistance in pneumococci is conceivable. However, many resistance surveillance studies suffer from inaccuracies like the sampling of a selected patient population, restricted geographical sampling, and undefined requirements of the user, so that the results are biased. The number of national centers is most often limited with one to two participating laboratories, so that such studies are point prevalence but not surveillance studies. Selected samples are analyzed predominantly as either hospitalized patients or patients at risk or those in whom therapy failed are sampled; however, fluoroquinolones are most frequently prescribed by the general practitioner. Selected sampling results in a significant over-estimation of fluoroquinolone resistance in outpatients. Furthermore, the requirements of the users are often not met; the prescribing physician, the microbiologist, the infection control specialist, public health and regulatory authorities, and the pharmaceutical industry have diverse interests, which, however, are not addressed by different designs of a surveillance study. Tools should be developed to provide customer-specific datasets.

CONCLUSION

Consequently, most surveillance studies suffer from well recognized but uncorrected biases or inaccuracies. Nevertheless, they provide important information that allows the identification of trends in pathogen incidence and antimicrobial resistance.