Susceptibility of Escherichia coli from community-acquired urinary tract infection to fosfomycin, nitrofurantoin, and temocillin in Korea

Susceptibility to Fosfomycin and Nitrofurantoin of ESBL-Positive Escherichia coli and Klebsiella pneumoniae Isolated From Urine of Pediatric Patients

BACKGROUND

Pediatric urinary tract infection (UTI) caused by extended-spectrum β-lactamase (ESBL)-positive gram-negative bacilli (GNB) has limited options for oral antibiotic treatment. The purpose of this study was to investigate the susceptibility of ESBL-positive Escherichia coli and Klebsiella pneumoniae isolates from pediatric urine samples to two oral antibiotics (fosfomycin and nitrofurantoin).

METHODS

From November 2020 to April 2022, ESBL-positive E. coli and K. pneumoniae isolates from urine samples were collected at Samsung Medical Center, Seoul, Korea. Patients over 18 years of age or with malignancy were excluded. For repeated isolates from the same patient, only the first isolate was tested. Minimum inhibitory concentrations (MICs) were measured using agar (fosfomycin) or broth (nitrofurantoin) dilution methods. MIC50 and MIC90 were measured for fosfomycin and nitrofurantoin in both E. coli and K. pneumoniae.

RESULTS

There were 117 isolates from 117 patients, with a median age of 7 months (range, 0.0-18.5 years). Among 117 isolates, 92.3% (108/117) were E. coli and 7.7% (9/117) were K. pneumoniae. Isolates from the pediatric intensive care unit (PICU) and general ward (GW) was 11.1% (13/117) and 88.9% (104/117), respectively. Among 108 E. coli isolates, MIC50 and MIC90 for fosfomycin were 0.5 μg/mL and 2 μg/mL, respectively. Fosfomycin susceptibility rate was 97.2% (105/108) with a breakpoint of 128 μg/mL. Fosfomycin susceptibility rate was significantly lower in PICU isolates than in GW isolates (81.8% vs. 99.0%, P = 0.027). For nitrofurantoin, both the MIC50 and MIC90 were 16 μg/mL. Nitrofurantoin susceptibility rate was 96.3% (104/108) with a breakpoint of 64 μg/mL based on Clinical and Laboratory Standards Institute guidelines. Among the nine K. pneumoniae isolates, the MIC50 and MIC90 for fosfomycin was 2 μg/mL and 32 μg/mL, respectively. MIC50 and MIC90 for nitrofurantoin were 64 μg/mL and 128 μg/mL, respectively.

CONCLUSION

For uncomplicated UTI caused by ESBL-positive GNB in Korean children, treatment with fosfomycin and nitrofurantoin for E. coli infections can be considered as an effective oral therapy option.

Hospital Urinary Tract Infections in Healthcare Units on the Example of Mazovian Specialist Hospital Ltd

Microbiological diagnostics is of great importance in limiting the spread of nosocomial infections. The information on etiological agents of infections and their susceptibility to antibiotics enables a quick response in the case of a suspected epidemic outbreak. The aim of this study is to analyze the incidence of nosocomial urinary tract infections among patients hospitalized in hospital wards over a period of 2 years and to determine the predominant etiological agent depending on the method of clinical specimen collection. Data from the Mazovian Specialist Hospital (MSH) in Radom constitute the material for the preparation of this study. Urine was collected using two methods. The first one was the method of collecting urine from the central stream, while the second method was urine collected from patients with a urinary catheter in place. The statistical calculations were conducted using the statistical software. Based on hospital data, it was shown that 5,870 urine tests were performed during the period under review, of which 2,070 were positive. The number of positive results in 2021 decreased by 2.84% compared to that in 2020. On the basis of the statistical analysis, differences in the occurrence of multiple strains were observed between catheter-based and midstream urine collection. Differences were observed especially for Acinetobacter baumannii, Candida albicans, Escherichia coli, and Pseudomonas aeruginosa. A. baumannii, C. albicans, and P. aeruginosa were significantly more frequently found in urine samples collected through the catheter than from the midstream. Furthermore, E. coli (51.56%) and Enterococcus species (25.46%) were more frequent when collected from the middle stream than when urine was collected through a catheter. However, for the strain K. pneumoniae, the results were comparable when urine was collected from catheterized patients (13.83%) and from midstream (13.35%). Urinary tract infection among hospitalized patients of the Mazovian Specialist Hospital in Radom was diagnosed quite frequently. In 2021, 32 more urine cultures were performed than in 2020. In the analyzed period, among all ordered urine cultures, 35.27% of samples were positive.

Prevalence and resistance pattern of uropathogens from community settings of different regions: an experience from India

Introduction

Urinary tract infection (UTI) is one of the most common infections in clinical practice worldwide in both healthcare and community settings causing significant morbidity and mortality. It is one of the major conditions at the community level treated empirically and regarded as a potential cause of emergence of antimicrobial resistance (AMR). Limited information is available regarding community-acquired UTI (CA-UTI) from India.

Methodology

This is a first of its kind, multicentric-cross-sectional study at the community level targeting patients attending the out-patient department (OPD) of the community health centre (CHC) from four geographical regions (North, South, West and East) of India. The study had been designed to determine the epidemiology, antibiogram profile and identification of extended-spectrum beta-lactamase (ESBL) producer and carbapenem resistant (CR) uropathogens. Samples were collected prospectively from UTI suspected patients coming at CHC and processed at the tertiary healthcare centres using a common standard operating procedure. Clinical history of all the patients exhibiting significant bacteriuria was collected and data was analysed.

Result

Overall, 250 out of a total of 2459 (10.1 %) urine samples were positive for bacteria with significant bacteriuria (adult: paediatrics, 6.7 : 1). Females were predominantly affected (male: female, 1 : 2.9). History of recent episode of UTI was observed as the commonest risk factor followed by diabetes mellitus. Altogether, 86 % of total cases were caused by Escherichia coli (68 %) and Klebsiella pneumoniae (17.6 %) together. Among the commonly used oral antibiotics for the Gram-negative bacilli (GNB), the highest resistance was observed against beta-lactams, first- and second-generation cephalosporins, fluoroquinolones and co-trimoxazole. Overall, the prevalence of ESBL producer and CR isolates were 44.8, and 4.3 %, respectively. However, the ESBL production, CR and nitrofurantoin resistance among the uropathogenic E. coli (UPEC) isolates was 52.8, 5.1 and 14 %, respectively. No resistance was found against fosfomycin among the UPEC isolates.

Conclusion

The current study highlights the increasing incidence of AMR among uropathogens at the community-settings of India. A significant percentage of ESBL producers among the isolated UPEC and K. pneumoniae were observed. The currently available evidence supports the clinical recommendation of fosfomycin and nitrofurantoin for empiric therapy in CA-UTI in India.

First Detection of Klebsiella pneumoniae Isolate Co-Harboring Fosfomycin Resistance Gene fosA3 and blactx-m Among Gram Negative Urine Isolates in a Turkish Hospital

The most common gram-negative pathogens in urinary tract infections are Escherichia coli and Klebsiella pneumoniae. Therapy that is often empirical relies on local antibiotic resistance data, hence monitorization of antimicrobial resistance periodically in each hospital is a requirement. In this study, antibiotic susceptibility profiles of consecutive urinary isolates (E. coli [n = 235] and K. pneumoniae [n = 56]) of adult patients collected between February 2018 and February 2019 from inpatients in Hacettepe University Hospital were assessed. Isolates resistant to fosfomycin (minimum inhibitory concentration >32 mg/L) were further investigated for the presence of fosA, fosA3, and fosC2. Fosfomycin susceptibility was determined by agar dilution method. Broth microdilution method was performed for amikacin, gentamicin, ceftazidime, ceftriaxone, meropenem, ciprofloxacin, tigecycline, trimethoprim/sulfamethoxazole (TMP/SMX), colistin, and piperacillin/tazobactam (PIP/TAZ). PCR method was employed to investigate fosA, fosA3, fosC2, and bla_CTX-M. Existence of fosA3 gene was confirmed by sequencing. Resistance rates to amikacin, gentamicin, ceftazidime, ceftriaxone, meropenem, ciprofloxacin, tigecycline, TMP/SMX, colistin, and PIP/TAZ were 2.7%, 18.5%, 25.4%, 33.0%, 3.4%, 45.4%, 2.4%, 43.6%, 6.2%, and 23.7%, respectively. Sixteen isolates (5.5%) were resistant to fosfomycin. Resistance was most frequently observed in K. pneumoniae (n = 9). fosA3 gene was detected in one fosfomycin-resistant K. pneumoniae isolate. This isolate also carried bla_CTX-M. fosC2 and fosA genes could not be detected in any of the isolates. In this study, we report for the first time the existence of fosA3 in Turkey and its association with the bla_CTX-M gene. As a result of increasing bla_CTX-M producing Enterobacterales isolates globally, increase in fosfomycin resistance may be expected in near future.

Challenges to Early Discharge of Patients with Upper Urinary Tract Infections by ESBL Producers: TMP/SMX as a Step-Down Therapy for Shorter Hospitalization and Lower Costs

Background

Urinary tract infections (UTIs) caused by extended spectrum beta-lactamase (ESBL) producing pathogens have increased and are treated with carbapenem in general. Carbapenem use is associated with prolonged hospitalization or daily outpatient visit. The aim of this study was to investigate patients with UTIs by ESBL-producing pathogens for early discharge using an old oral antibiotic, trimethoprim-sulfamethoxazole (TMP-SMX), which is susceptible to ESBL-producing pathogens.

Methods

Data on UTIs caused by ESBL-producing pathogens from a single tertiary hospital were collected retrospectively. Patients who had been treated with intravenous carbapenems or oral TMP/SMX were included. Patients’ clinical and microbiological outcomes were compared between oral TMP/SMX and ertapenem treatment groups.

Results

A total of 103 patients were included, 21 of whom had been treated with TMP/SMX, whereas 82 with ertapenem. Clinical outcomes between the two groups were not significantly different (TMP/SMX: 90.5%; ertapenem: 84.1%, p = 0.73). The microbiological cure rate was higher in the TMP/SMX group than in the ertapenem group (90.5% vs 58.5%, respectively, p = 0.01). The mean duration of hospitalization was significantly shorter in the TMP/SMX group than in the ertapenem group (8.00 ± 10.50 days vs 14.00 ± 37.00 days, p = 0.07). The mean duration of antibiotic treatment was longer in the ertapenem group than in the TMP/SMX group (16.45 ± 4.77 vs 12.76 ± 5.37 days, p = 0.006).

Conclusion

For susceptible pathogens, TMP/SMX may enable early discharge as an effective oral antibiotic treatment option for UTIs caused by ESBL-positive pathogens. Additionally, use of oral antibiotics can shorten hospital stays and reduce medical costs.

Fosfomycin Resistance in Escherichia coli Isolates from South Korea and in vitro Activity of Fosfomycin Alone and in Combination with Other Antibiotics

We investigated fosfomycin susceptibility in Escherichia coli clinical isolates from South Korea, including community-onset, hospital-onset, and long-term care facility (LTCF)-onset isolates. The resistance mechanisms and genotypes of fosfomycin-resistant isolates were also identified. Finally, the in vitro efficacy of combinations of fosfomycin with other antibiotics were examined in susceptible or extended spectrum β-lactamase (ESBL)-producing E. coli isolates. The fosfomycin resistance rate was 6.7% and was significantly higher in LTCF-onset isolates than community-onset and hospital-onset isolates. Twenty-one sequence types (STs) were identified among 19 fosfomycin-resistant E. coli isolates, showing diverse genotypes. fosA3 was found in only two isolates, and diverse genetic variations were identified in three genes associated with fosfomycin resistance, namely, GlpT, UhpT, and MurA. Some fosfomycin-resistant E. coli isolates carried no mutations. In vitro time-kill assays showed that fosfomycin alone did not exhibit an excellent killing activity, compared with ciprofloxacin in susceptible isolates and with ertapenem in ESBL producers. However, combining fosfomycin with cefixime or piperacillin-tazobactam eradicated susceptible or ESBL-producing isolates, respectively, even with 0.5× minimum inhibitory concentrations. Overall, we found a relatively high fosfomycin resistance rate in E. coli isolates from South Korea. Based on their genotypes and resistance mechanisms, most of the fosfomycin-resistant E. coli isolates might occur independently. Antibiotic combinations with fosfomycin could be a suitable therapeutic option for infections caused by E. coli isolates.

Evaluation of in vitro susceptibility of fosfomycin among Enterobacteriaceae isolates from urine cultures: A study from Puducherry

INTRODUCTION:

The increasing drug resistance among Gram-negative uropathogens and a lack of effective oral antibiotics have limited the therapeutic options available for urinary tract infections (UTIs). This shortage of newer antibiotics has paved the way for considering the use of older antibiotics such as fosfomycin. This study aims to evaluate the in vitro susceptibility of Enterobacteriaceae isolates to fosfomycin.

MATERIALS AND METHODS:

In this descriptive study conducted over a period of 6 months, we processed 1500 urine samples. The Enterobacteriaceae isolates were subjected to in vitro susceptibility testing to fosfomycin, in addition to the regularly used urinary antibiotics, by Kirby–Bauer disc-diffusion method.

RESULTS:

Of 1500 urine samples processed, 582 samples yielded the growth of pathogens. Enterobacteriaceae accounted for 392 (67.3%) of the isolates. Among these isolates, lower rates of resistance were observed for imipenem (4.1%) and fosfomycin (13.3%). Relatively higher rates of resistance were observed for nitrofurantoin (35.5%) and amikacin (30.9%). Nalidixic acid, norfloxacin, gentamicin, cefotaxime, and cotrimoxazole showed a high resistance rate of 82.7%, 69.6%, 52.3%, 69.1%, and 71.4%, respectively. All antibiotics, except fosfomycin, were in routine clinical use in our hospital. The low resistance (13.3%) to fosfomycin is indicative of its utility as an excellent urinary antibiotic.

CONCLUSIONS:

Uropathogenic Enterobacteriaceae isolates displayed excellent in vitro susceptibility to fosfomycin. These in vitro findings suggest the unexplored potential of fosfomycin as a superior therapeutic option for treating uncomplicated UTI.

Temocillin against Enterobacteriaceae isolates from community-acquired urinary tract infections: low rate of resistance and good accuracy of routine susceptibility testing methods

Background

Temocillin is an old 'revived' antibiotic that may play an important role in the treatment of febrile urinary tract infection (UTI). Data regarding its activity against current Enterobacteriaceae isolates as well as the performance of routine susceptibility testing methods are, however, scarce.

Objectives

To determine the MICs of temocillin for Enterobacteriaceae strains reflecting the current epidemiology and to analyse the accuracy of three commercial methods.

Methods

Enterobacteriaceae isolates causing community-acquired UTI were prospectively collected from September 2015 to January 2017 in two French centres. Temocillin MIC was determined by agar dilution (AD) as the reference method and then compared with: (i) susceptibility testing by disc diffusion; (ii) MIC determination by Etest; and (iii) MIC estimation by the Vitek 2 automated system.

Results

A total of 762 Enterobacteriaceae were analysed comprising 658 (86.4%) Escherichia coli and 37 (4.9%) ESBL-producing isolates. Susceptibility rate assessed by AD was 99.6% according to the 8 mg/L clinical breakpoint and was significantly lower against the ESBL-producing isolates than the non-ESBL-producing isolates (94.6% versus 99.9%, P < 0.01). The MIC50 and MIC90 for the total set were 3 and 6 mg/L, respectively. According to the 8 mg/L clinical breakpoint, the major error rate was <1% for disc diffusion and Etest, and significantly higher for Vitek 2 (4.3%, P < 0.01), but still low. No very major error was noticed.

Conclusions

Temocillin showed a high level of activity against Enterobacteriaceae from community-acquired UTI and good to excellent reliability of routine methods for susceptibility testing in such a setting.

Clinical effectiveness of oral antimicrobial therapy for acute pyelonephritis caused by extended-spectrum β-lactamase-producing Enterobacteriales

Infections caused by extended-spectrum β-lactamase-producing Enterobacteriales (ESBL-PE) are commonly treated with intravenous antibiotics. This study investigated whether oral antimicrobial therapy (OAT) is as effective as intravenous antimicrobial therapy (IVT) for acute pyelonephritis (APN) caused by ESBL-PE. A retrospective cohort of patients with APN caused by ESBL-PE was studied at a tertiary-care hospital from January 2014 through December 2016. The OAT group comprised patients treated with an appropriate oral antimicrobial agent following 7 days or less of IVT. The primary endpoint was treatment failure defined as clinical and/or microbiological failure. The secondary endpoint was length of hospital stay and recurrences of APN within 2 months and within 1 year. Propensity score matching and multivariable Cox proportional hazard modeling were used to minimize bias. Among 238 eligible cases, Escherichia coli (83.6%) was the most common pathogen. Sixty patients received OAT after a median of four days of appropriate IVT, and 178 patients completed treatment with IVT. Fluoroquinolones (58.3%) were the most commonly prescribed OAT, followed by trimethoprim-sulfamethoxazole and amoxicillin-clavulanate. OAT was not associated with treatment failure (adjusted OR 0.66; 95% CI 0.18-2.44) and hospitalization length was shorter in the OAT group (6.2 days versus 10.7 days; P < 0.01). APN recurrence caused by ESBL-PE infection within 2 months was not associated with OAT (adjusted HR 0.56; 95% CI 0.16-2.00). OAT reduced hospital stay without adverse effects on treatment outcome. OAT could be safely applied as a carbapenem-saving option in treatment of APN.

Resurrecting Old β-Lactams: Potent Inhibitory Activity of Temocillin against Multidrug-Resistant Burkholderia Species Isolates from the United States

Burkholderia spp. are opportunistic human pathogens that infect persons with cystic fibrosis and the immunocompromised. Burkholderia spp. express class A and C β-lactamases, which are transcriptionally regulated by PenR_A through linkage to cell wall metabolism and β-lactam exposure. The potency of temocillin, a 6-methoxy-β-lactam, was tested against a panel of multidrug-resistant (MDR) Burkholderia spp. In addition, the mechanistic basis of temocillin activity was assessed and compared to that of ticarcillin. Susceptibility testing with temocillin and ticarcillin was conducted, as was biochemical analysis of the PenA1 class A β-lactamase and AmpC1 class C β-lactamase. Molecular dynamics simulations (MDS) were performed using PenA1 with temocillin and ticarcillin. The majority (86.7%) of 150 MDR Burkholderia strains were susceptible to temocillin, while only 4% of the strains were susceptible to ticarcillin. Neither temocillin nor ticarcillin induced bla expression. Ticarcillin was hydrolyzed by PenA1 (k _cat/K_m = 1.7 ± 0.2 μM^-1 s^-1), while temocillin was slow to form a favorable complex (apparent K_i [K_{i  app}] = ∼2 mM). Ticarcillin and temocillin were both potent inhibitors of AmpC1, with K_{i  app} values of 4.9 ± 1.0 μM and 4.3 ± 0.4 μM, respectively. MDS of PenA revealed that ticarcillin is in an advantageous position for acylation and deacylation. Conversely, with temocillin, active-site residues K73 and S130 are rotated and the catalytic water molecule is displaced, thereby slowing acylation and allowing the 6-methoxy of temocillin to block deacylation. Temocillin is a β-lactam with potent activity against Burkholderia spp., as it does not induce bla expression and is poorly hydrolyzed by endogenous β-lactamases.

Recent advances in managing lower urinary tract infections

Urinary tract infections (UTIs) are among the most common bacterial infections. Traditionally, all symptomatic UTIs are tested and treated. The use of antibiotics has resulted in an antibiotic resistance crisis, and we have limited options for managing UTIs. Currently, we live in the era of antimicrobial resistance and may live in other eras like the era of the microbiome. New insights might provide an opportunity to prevent the overuse and misuse of antibiotics and could enable the development of innovate managing strategies.

Community-Acquired Urinary Tract Infection by Escherichia coli in the Era of Antibiotic Resistance

Urinary tract infections (UTIs) caused by Escherichia coli (E. coli) are the most common types of infections in women. The antibiotic resistance of E. coli is increasing rapidly, causing physicians to hesitate when selecting oral antibiotics. In this review, our objective is to ensure that clinicians understand the current seriousness of antibiotic-resistant E. coli, the mechanisms by which resistance is selected for, and methods that can be used to prevent antibiotic resistance.

Marker Pen Device with Concentration Gradient Nib for Antibiotic Susceptibility Testing

BACKGROUND

Pen-based devices have emerged as useful tools for measuring pH and glucose, and for fabricating microchannels and microarrays. Pen-based devices take advantage of flexible patterning, inexpensive costs, and small volumes, thereby saving time and increasing efficiency. We have developed a gradient nib marker pen device that generated simultaneously different antibiotic concentrations in bacteria antibiotic susceptibility testing (AST).

METHODS

The device can deposit on the target surface with the antibiotic gradient. The designed polyester fiber nibs are a highly uniform porosity with unidirectional orientation and produce a visible gradient pattern.

RESULTS

We have demonstrated and quantitatively analyzed bacterial growth after antibiotic marking. The antibiotic marking produces an inhibition zone of bacterial growth. The inhibition zones of bacterial growth are captured and converted to 8-bit grayscale images, and then quantified by gray values using the Image J program. A profile of the inhibition zone showed different gray values in response to bacterial viability.

CONCLUSION

The gradient nib marker pen device can be used to determine the quantitative antibiotic concentration based on the relationship between gray values and bacterial density conveniently without requiring a series of dilution tubes, including nutrient medium, and diversely diluted antibiotics.

Multi-drug-resistant Gram-negative bacteria causing urinary tract infections: a review

Urinary tract infections (UTIs) are among the most frequent infectious diseases affecting humans, and represent an important public health problem with a substantial economic burden. Due to the high empiric use of antibiotics for the treatment of UTI, antibacterial resistance of Enterobacteriaceae, specifically the main uropathogens Escherichia coli and Klebsiella pneumoniae, has significantly increased worldwide. In this article the worldwide epidemiology of resistant Gram-negative bacteria causing UTIs, with a special focus on extended spectrum beta lactamase (ESBL) positive pathogens, as well as new threats such as multi-drug-resistant (MDR) clones (e.g. E. coli 131 (ST131) and K. pneumoniae ST258), are reviewed. The increased prevalence of MDR Enterobacteriaceae, limiting available treatment options for infections caused by these organisms, and the lack of new antibiotics provide good rationale for using older antibiotics, such as fosfomycin, that have been shown to retain some activity against MDR bacteria.

Clinical Practice Guidelines for the Antibiotic Treatment of Community-Acquired Urinary Tract Infections

Urinary tract infections (UTIs) are infectious diseases that commonly occur in communities. Although several international guidelines for the management of UTIs have been available, clinical characteristics, etiology and antimicrobial susceptibility patterns may differ from country to country. This work represents an update of the 2011 Korean guideline for UTIs. The current guideline was developed by the update and adaptation method. This clinical practice guideline provides recommendations for the diagnosis and management of UTIs, including asymptomatic bacteriuria, acute uncomplicated cystitis, acute uncomplicated pyelonephritis, complicated pyelonephritis related to urinary tract obstruction, and acute bacterial prostatitis. This guideline targets community-acquired UTIs occurring among adult patients. Healthcare-associated UTIs, catheter-associated UTIs, and infections in immunocompromised patients were not included in this guideline.

Community-acquired Lower Urinary Tract Infections: Etiology, Antimicrobial Resistance, and Treatment Results in Female Patients

Background/Purpose:

Most community-acquired urinary tract infections (UTIs) are usually treated empirically. The knowledge of antibiotic resistance patterns of the microorganisms causing UTI is essential for defining the empirical treatment.

Objective:

The aim of the present study is to determine the distribution of bacterial strains isolated from lower UTIs and their resistance patterns against commonly used antimicrobial agents and treatment results in female patients.

Subjects and Methods:

This is a retrospective analysis of medical case records of 90 female patients with lower UTI for a period of 4 years from January 2013 to December 2016 in a tertiary care hospital in the Trakya region of Turkey.

Results:

The most common causative agent was Escherichia coli (66.6% of cases) followed by Klebsiella pneumoniae (16.6%). Fosfomycin was the most active agent against E. coli (resistant isolates: 5.5%), followed by nitrofurantoin (resistant isolates: 7.4%). Extended-spectrum beta-lactamases (ESBLs) production was observed in 29 (32.2%) isolates (22 in E. coli, 6 in K. pneumoniae, and 1 in Enterobacter spp.). The antimicrobial resistance rates among ESBL-producing E. coli isolates for trimethoprim-sulfamethoxazole, ciprofloxacin, fosfomycin, and nitrofurantoin were 77.7%, 72.7%, 13.6%, and 18.2%, respectively (P < 0.05). The estimated microbiological eradication rates for nitrofurantoin and fosfomycin were 89.7% and 83.8%, respectively.

Conclusions:

The results of the present study indicate that nitrofurantoin and fosfomycin may be considered for empirical therapy of lower UTIs in Trakya region of Turkey.

Activity of temocillin and 15 other agents, including fosfomycin and colistin, against Enterobacteriaceae in Hong Kong

Limited data are available on temocillin susceptibilities in Enterobacteriaceae from Asian countries where antimicrobial resistance is prevalent. The in vitro activities of temocillin and 15 commonly used antimicrobials against 613 non-duplicate blood (n = 310) and urine (with clinically significant bacteriuria; n = 303) isolates of Enterobacteriaceae from patients who attended 3 out of 7 clusters of public hospitals of the Hospital Authority, Hong Kong, during 2015/2016 were tested. Minimum inhibitory concentrations (MICs) were determined by Clinical and Laboratory Standards Institute (CLSI) microbroth dilution (agar dilution with fosfomycin). For temocillin, MICs were also obtained using the British Society of Antimicrobial Chemotherapy (BSAC) microbroth dilution method and interpreted using the BSAC breakpoints. Overall, 93.0% (570) isolates were susceptible to temocillin using BSAC systemic breakpoint (≤8 mg/L) and all except 2 isolates were susceptible using the urinary breakpoint (≤32 mg/L). The extended spectrum beta-lactamase (ESBL) positivity rate was 23.2% (118 out of 508 E. coli, Klebsiella spp., Proteus spp.). Temocillin resistance rate to ESBL-positive isolates was 16.1% using the systemic breakpoint of ≤8 mg/L (MIC₅₀ and MIC₉₀ were 8 mg/L and 16 mg/L respectively). Two isolates (1 E. coli, temocillin MIC 64 mg/L, 1 Klebsiella sp., MIC 32 mg/mL) were resistant to meropenem and possessed the NDM-5 and KPC-2 genes respectively. Other susceptibility rates were: amoxicillin/clavulanate (59.1%), trimethoprim/sulfamethoxazole (62.5%), ciprofloxacin (71.5%), ceftriaxone (75.4%), nitrofurantoin (76.4%), gentamicin (78.3%), cefepime (81.1%), ceftazidime (83.5%), piperacillin/tazobactam (86%), colistin (88.8%), tigecycline (89.4%), fosfomycin (92.8%), ertapenem (99.0%), amikacin (99.2%) and meropenem (99.7%). Temocillin may be a useful alternative for the treatment of infections caused by ESBL and multi-drug-resistant Enterobacteriaceae in Hong Kong, particularly as resistance rates to ciprofloxacin, nitrofurantoin and piperacillin/tazobactam are high.

Contemporary resistance trends and mechanisms for the old antibiotics colistin, temocillin, fosfomycin, mecillinam and nitrofurantoin

Recently there has been a renewed interest in reviving older antimicrobial agents, particularly those with activity against multidrug-resistant Gram-negative bacilli. Because many such antimicrobials are not licensed in all countries, there is a paucity of international surveillance data, and none of these agents is part of any antimicrobial resistance surveillance on the level of the EU. Some of the agents are used in lower urinary tract infection, whereas most available supranational surveillance data pertain to severe infections such as bloodstream infections. Among old antimicrobial agents, the most interesting compounds from a clinical perspective are the two intravenous agents colistin and temocillin, the two oral agents pivmecillinam and nitrofurantoin, and fosfomycin, which is available both for intravenous and oral use. The most interesting target microorganisms are Enterobacteriaceae, although colistin also has good activity against Pseudomonas aeruginosa and Acinetobacter species. Recent European surveillance data point to approximately 5% resistance to colistin in general among Klebsiella pneumoniae, whereas resistance in carbapenemase-producing Enterobacteriaceae may be up to 15% to 20% in some settings. Temocillin is stable against many extended-spectrum β-lactamase-producing Enterobacteriaceae and some carbapenemase producers, but low-level resistance is not uncommon in extended-spectrum β-lactamase producers, and high-level resistance is always seen with OXA-48 group carbapenemases. Fosfomycin resistance is rare in areas with limited use but increasing is in countries with higher usage. Resistance levels to mecillinam and nitrofurantoin are generally low in EU countries, but clinical data supporting treatment efficacy of multidrug-resistant strains are few. Systematic surveillance of the above-mentioned agents will be important, particularly for those agents used in severe infections.

A comparison of the clinical characteristics of elderly and non-elderly women with community-onset, non-obstructive acute pyelonephritis

BACKGROUND/AIMS

Acute pyelonephritis (APN) is the most common cause of community-onset bacteremia in hospitalized elderly patients. The objectives of this study were to investigate the differences in the clinical and microbiological data of hospitalized elderly and non-elderly women with community-onset APN.

METHODS

Women with community-onset APN as a discharge diagnosis were identified from January 2004 to December 2013 using an electronic medical records system. We compared the clinical and microbiologic data in elderly and non-elderly women with community-onset APN due to Enterobacteriaceae.

RESULTS

Of the 1,134 women with community-onset APN caused by Enterobacteriaceae, 443 were elderly and 691 were non-elderly women. The elderly group had a lower frequency of upper and lower urinary tract symptoms/signs than the non-elderly. The incidence of bacteremia, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, patients with a C-reactive protein (CRP) level ≥ 15 mg/dL, and patients with a leukocyte count ≥ 15,000/mm(3) in the blood, were significantly higher in the elderly group than in the non-elderly group. The proportion of patients requiring hospitalization for 10 days or more was significantly higher in the elderly group compared to the non-elderly group (51.5% vs. 26.2%, p < 0.001). The clinical cure rates at 4 to 14 days after the end of therapy were 98.3% (338/344) and 97.4% (519/533) in the elderly and non-elderly groups, respectively (p = 0.393).

CONCLUSIONS

Elderly women with APN exhibit higher serum CRP levels, a higher frequency of bacteremia, a higher proportion of ESBL-producing uropathogens, and require a longer hospitalization than non-elderly women, although these patients may not complain of typical urinary symptoms.