Comparative in vitro activity of oral antimicrobial agents against Enterobacteriaceae from patients with community-acquired urinary tract infections in three European countries

Development and maintenance of consensus recommendations on pediatric outpatient antibiotic therapy in Germany: a framework for rational use

In pediatric outpatient care, overuse and misuse of antibiotics is linked to a high risk of adverse events and increased antibiotic resistance. In 2019, building upon the work of the Antibiotic Therapy in Bielefeld (AnTiB) project (founded in 2016), a collaboration among the AnTiB, the German Society for Pediatric Infectious Diseases (DGPI), and the Professional Association of Outpatient Pediatricians and Adolescent Physicians (BVKJ) was established to develop consensus recommendations for antibiotic therapy in pediatric outpatient settings in Germany. This working group became the Antibiotic Stewardship in Outpatient Pediatrics (ABSaP). ABSaP institutes recommendations for antibiotic use in outpatient pediatric settings in Germany and updates them regularly. The ABSaP guidelines recommend restrictive, targeted, evidence-based prescription practices for antibiotics used to treat common infections among pediatric outpatients. This expert-driven, pragmatic, best-practice guidance is designed to be a living document. ABSaP's most recent update was published in March 2024. The recommendations aim to guide and standardize rational antibiotics use by emphasizing the importance of avoiding unnecessary prescriptions, while also promoting the application of narrow-spectrum antibiotics, short-duration therapy, and watchful waiting, when treating mild, self-limiting infections in children without significant risk factors.

CONCLUSIONS

ABSaP's guidelines may provide a model for others, as well as offer a basis for discussing practical, effective antibiotic stewardship (ABS) measures in pediatric primary care. An international, expert consensus on ABS for pediatric outpatients could help promote a culture of responsible antibiotic use, improve prescribing safety, and contribute to broader ABS efforts.

WHAT IS KNOWN

• Overuse and misuse of antibiotics are associated with adverse events and increased antibiotic resistance, prompting the need for effective antibiotic stewardship initiatives. • The Antibiotic Stewardship in Outpatient Pediatrics (ABSaP) working group was established to develop and regularly update evidence-based best practice recommendations for the targeted and restrictive use of antibiotics in pediatric outpatient settings in Germany.

WHAT IS NEW

• The most recent update of the ABSaP guidelines was published in March 2024, emphasizing the importance of narrow-spectrum antibiotics, short-duration therapy, and watchful waiting for mild infections, aiming to standardize rational antibiotic use in children. • The ABSaP guidelines have become widely accepted in Germany and are now being translated into English to foster international dialogue and collaboration on antibiotic stewardship in pediatric primary care, potentially serving as a model for similar initiatives in other countries.

Multidrug resistance in urinary E. coli higher in males compared to females

BACKGROUND

Urinary tract infections (UTIs) are common however the widespread use of antibiotics has led to a rise in antimicrobial resistance (AMR) amongst uropathogens, rendering a significant proportion of infections resistant to first line treatment. AMR in UTIs may differentially affect men and women, younger and older patients. The purpose of this study was to investigate MDR (multi-drug resistance) and AMR in males and females in an Australian health district.

METHODS

There were 85,844 E. coli urinary isolates (2007-2020) analysed from adult patients. An E. coli isolate with MDR was defined as resistant to at least 1 agent in ≥ 3 antimicrobial classes. Chi-square tests and relative risk were calculated by comparing resistance in males and females and by age for antibiotics commonly used to treat UTIs in hospital and community collected samples.

RESULTS

There was a higher proportion of MDR E. coli in males compared to females in both the community (6.4% vs. 5.2%, P < 0.001) and hospital datasets (16.5% vs. 12.8%, P < 0.001). The proportions of MDR for both males and females were significantly higher in the hospital setting. Resistance rates were higher in males compared to females for amoxicillin, amoxicillin/clavulanate, cephalexin and norfloxacin (p < 0.005), though not for trimethoprim. Antibiotic resistance was seen to increase over time.

CONCLUSIONS

A higher proportion of MDR E. coli were noted in urine samples from males compared with females, possibly due to the increased likelihood of prior treatment for UTIs in men. Antimicrobial stewardship interventions could be targeted towards this cohort to address increasing rates of AMR.

Flemish consensus statement on the prevention, diagnosis and treatment of urinary tract infections in older nursing home residents

BACKGROUND

Urinary tract infections (UTIs) are one of the most commonly reported infections in Belgian nursing home residents. In older adults, UTI diagnosis and management is complex, often leading to over-diagnosis and irrational antimicrobial use, stressing the need for a guideline approach.

OBJECTIVES AND METHODS

A consensus statement on the prevention, diagnosis and treatment of UTIs in older adults residing in nursing homes was developed in a collaborative effort between the Flemish Hospital Outbreak Support Teams, the Flemish Agency for Care and Health, the Association of the Flemish Coordinating and Advising General Practitioners, the Belgian Association of Urology, the Belgian Society for Gerontology and Geriatrics and PhD researchers based on a combination of clinical expertise, (inter)national guidelines and peer-reviewed studies.

RESULTS

Optimizing fluid intake, appropriate toilet behaviour and posture, mobilization and local estrogen therapy in women are of proven value in UTI prevention, whereas the use of cranberry and probiotics is not to be advocated. The importance of avoiding bladder catheterization is stressed. In older nursing home residents, the diagnosis of UTIs remains challenging, mostly due to atypical systemic symptoms. A consensus diagnostic algorithm for UTI among residents with and without a urinary catheter was developed, including the presence of suggestive clinical symptoms and a positive urine culture. Urine dipsticks have a high negative but a low positive predictive value. C-reactive protein point-of-care testing is not recommended. Asymptomatic bacteriuria should not be screened for, in order to avoid unnecessary triggers for treatment. In cystitis, nitrofurantoin is the primary choice for treatment, with fosfomycin as an alternative; in prostatitis and uncomplicated pyelonephritis a fluoroquinolone is the advocated empirical antimicrobial.

Fluoroquinolone resistance in complicated urinary tract infections: association with the increased occurrence and diversity of Escherichia coli of clonal complex 131, together with ST1193

Introduction

Urinary tract infections (UTIs) are one of the leading causes of multidrug-resistance (MDR) spread and infection-related deaths. Escherichia coli is by far the main causative agent. We conducted a prospective study on complicated urinary tract infections (cUTIs) i) to monitor the high-risk clones that could be compromising the therapeutic management and ii) to compare the cUTI etiology with uncomplicated infections (uUTIs) occurring in the same period and health area.

Methods

154 non-duplicated E. coli recovered from cUTIs in 2020 at the Hospital Universitario Central de Asturias (Spain) constituted the study collection.

Results

Most cUTI isolates belonged to phylogroup B2 (72.1%) and met the uropathogenic (UPEC) status (69.5%) (≥3 of chuA, fyuA, vat, and yfcV genes). MDR was exhibited by 35.7% of the isolates, similarly to data observed in the uUTI collection. A significant difference observed in cUTI was the higher level of fluoroquinolone resistance (FQR) (47.4%), where the pandemic clonal groups B2-CC131 and B2-ST1193 (CH14-64) comprised 28% of the 154 E. coli, representing 52.1% of the FQR isolates. Other prevalent FQR clones were D-ST69 (CH35-27), D-ST405 (CH37-27), and B2-ST429 (CH40-20) (three isolates each). We uncovered an increased genetic and genomic diversity of the CC131: 10 different virotypes, 8 clonotypes (CH), and 2 STs. The presence of bla CTX-M-15 was determined in 12 (7.8%) isolates (all CC131), which showed 10 different core genome (cg)STs and 2 fimH types (fimH30 and fimH602) but the same set of chromosomal mutations conferring FQR (gyrA p.S83L, gyrA p.D87N, parC p.S80I, parC p.E84V, and parE p.I529L). In addition, the plasmidome analysis revealed 10 different IncF formulae in CC131 genomes.

Conclusion

We proved here that non-lactose fermenting screening, together with the detection of O25b (rfbO25b), H4 (fliCH4), and H5 (fliCH5) genes, and phylogroup and clonotyping assignation, is a reasonable approach that can be easily implemented for the surveillance of emerging high-risk clones associated with FQR spread in cUTIs, such as the uncommonly reported O25b:H4-B2-ST9126-CC131 (CH1267-30). Since E. coli CC131 and ST1193 are also involved in the community uUTIs of this health area, interventions to eradicate these MDR clones, along with surveillance for other emerging ones, are essential for antibiotic use optimization programs.

Effectiveness of fosfomycin trometamol as oral step-down therapy for bacteraemic urinary tract infections due to MDR Escherichia coli: a post hoc analysis of the FOREST randomized trial

BACKGROUND

Fosfomycin is a potentially attractive option as step-down therapy for bacteraemic urinary tract infections (BUTI), but available data are scarce. Our objective was to compare the effectiveness and safety of fosfomycin trometamol and other oral drugs as step-down therapy in patients with BUTI due to MDR Escherichia coli (MDR-Ec).

METHODS

Participants in the FOREST trial (comparing IV fosfomycin with ceftriaxone or meropenem for BUTI caused by MDR-Ec in 22 Spanish hospitals from June 2014 to December 2018) who were stepped-down to oral fosfomycin (3 g q48h) or other drugs were included. The primary endpoint was clinical and microbiological cure (CMC) 5-7 days after finalization of treatment. A multivariate analysis was performed using logistic regression to estimate the association of oral step-down with fosfomycin with CMC adjusted for confounders.

RESULTS

Overall, 61 patients switched to oral fosfomycin trometamol and 47 to other drugs (cefuroxime axetil, 28; amoxicillin/clavulanic acid and trimethoprim/sulfamethoxazole, 7 each; ciprofloxacin, 5) were included. CMC was reached by 48/61 patients (78.7%) treated with fosfomycin trometamol and 38/47 (80.9%) with other drugs (difference, -2.2; 95% CI: -17.5 to 13.1; P = 0.38). Subgroup analyses provided similar results. Relapses occurred in 9/61 (15.0%) and 2/47 (4.3%) of patients, respectively (P = 0.03). The adjusted OR for CMC was 1.11 (95% CI: 0.42-3.29, P = 0.75). No relevant differences in adverse events were seen.

CONCLUSIONS

Fosfomycin trometamol might be a reasonable option as step-down therapy in patients with BUTI due to MDR-Ec but the higher rate of relapses would need further assessment.

Prevalence of Fosfomycin Resistance Among Enterobacterales Isolates in A Tertiary Care Hospital from Turkey

Objective

Urinary tract infections are one of the most common causes of morbidity around the world. Fosfomycin is a specific broad-spectrum antibiotic used to treat these infections. However, in recent years, many studies have reported increased fosfomycin resistance in Enterobacterales isolates. Therefore, this study aimed to evaluate the distribution of pathogens isolated from urine samples and find the fosfomycin resistance rates over nine years (2012-2020).

Materials and Methods

A total of 18,884 uropathogenic Enterobacterales isolates were included in the study between 2012 and 2020. The isolates were identified by VITEK® 2 Compact (bioMérieux, Marcy l'Etoile, France), and the antimicrobial susceptibilities of the isolates were also evaluated using the VITEK® MS automated system (bioMérieux, Marcy l'Etoile, France).

Results

Escherichia coli (64.04%) was the most common bacteria among Enterobacterales. Fosfomycin resistance rates were 1.98%, 21.64%, and 10.36% in E. coli, Klebsiella pneumoniae, and all bacteria, respectively. The 34.97% of isolates were extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, and the fosfomycin resistance rate was 13.08% in these isolates. In addition, fosfomycin resistance rates were found as 3.06% and 23.84% in ESBL-producing E. coli and ESBL-producing K. pneumoniae, respectively.

Conclusion

Fosfomycin seems a good option for effectively treating UTIs caused by E. coli. On the other hand, we found that fosfomycin resistance tends to increase over the years. Therefore, we recommend further studies to evaluate fosfomycin resistance.

Urinary Tract Infections Caused by Uropathogenic Escherichia coli Strains—New Strategies for an Old Pathogen

Urinary tract infections (UTIs) are among the most common infections worldwide. Uropathogenic Escherichia coli (UPECs) are the main causative agent of UTIs. UPECs initially colonize the human host adhering to the bladder epithelium. Adhesion is followed by the bacterial invasion of urothelial epithelial cells where they can replicate to form compact aggregates of intracellular bacteria with biofilm-like properties. UPEC strains may persist within epithelial urothelial cells, thus acting as quiescent intracellular bacterial reservoirs (QIRs). It has been proposed that host cell invasion may facilitate both the establishment and persistence of UPECs within the human urinary tract. UPEC strains express a variety of virulence factors including fimbrial and afimbrial adhesins, invasins, iron-acquisition systems, and toxins, which cooperate to the establishment of long lasting infections. An increasing resistance rate relative to the antibiotics recommended by current guidelines for the treatment of UTIs and an increasing number of multidrug resistant UPEC isolates were observed. In order to ameliorate the cure rate and improve the outcomes of patients, appropriate therapy founded on new strategies, as alternative to antibiotics, needs to be explored. Here, we take a snapshot of the current knowledge of coordinated efforts to develop innovative anti-infective strategies to control the diffusion of UPECs.

A Three-Year Look at the Phylogenetic Profile, Antimicrobial Resistance, and Associated Virulence Genes of Uropathogenic Escherichia coli

Uropathogenic Escherichia coli is the most common cause of urinary tract infections, resulting in about 150 million reported annual cases. With multidrug resistance on the rise and the need for global and region surveillance, this investigation looks at the UPEC isolates collected for a 3-year period, with a view of ascertaining their antimicrobial susceptibility patterns and associated virulence determinants. The identification of bacteria isolates, antimicrobial susceptibility, and extended-spectrum beta-lactamases (ESBLs) production was determined with a Vitek 2 Compact Automated System (BioMerieux, Marcy L’Etoile, France). ESBLs were confirmed by the combined disc test (CDT) and basic biochemical test. The isolates were distributed into A (11%), B1 (6%), B2 (62.4%), and D (20.6%). Resistance to the penicillin group was high, between 88% and 100%. Additionally, resistance was high to cephalosporins (100%) in 2017 and 2018. The isolates were all sensitive to tigecycline, while resistance against imipenem and meropenem was low, at 4–12% in 2017 and 2018 and 0% in 2019. The results also showed that ESBL isolates were seen in 2017 and 2018. They were confirmed positive to CTX/CLA (88.5%) and CAZ/CLA (85%). By 2019, the number of resistant isolates reduced, showing only 4% ESBL isolates. Two virulence genes, fimH (46%) and papE/F (15%), were detected among the isolates by PCR. In conclusion, this study found that phylogroups B2 and D carried the most virulence genes as well as MDR and ESBL characteristics, suggesting the UPEC strains to be extraintestinal pathogens responsible for UTIs.

Susceptibility to first choice antimicrobial treatment for urinary tract infections to Escherichia coli isolates from women urine samples in community South Brazil

E. coli is the main pathogen of UTI. It is important to be aware the local epidemiological data for an appropriate initial treatment. Resistance to antimicrobial agents has increased, especially to first-choice antibiotics in the treatment of cystitis. There are few studies on the sensivity profile of community uropathogen in our region.

OBJECTIVE

To characterize antimicrobials the sensitivity profile to E. coli isolated from urocultures of women treated at Basic Health Units and Emergency Care Units of Londrina- Paraná- Brazil during a period of 12 months (June 1, 2016 to June 1, 2017).

METHODOLOGY

A cross-sectional study was carried out from June 2016 to June 2017. All urine samples collected in the Basic Health Units and Emergency Departments in the city of Londrina (Paraná State, Brazil) were sent to a Central Laboratory where the identification and antimicrobial susceptibility testing were performed. Clinical Laboratory Standards Institute (CLSI) breakpoints were used for the interpretation of susceptibility testing results.

RESULTS

56,555 urine cultures were performed in the period, of which 8,832 were positive, of which 5,377 were women. Of these samples, 4.7% were enterobacteria producing extended-spectrum beta-lactamases (ESBL) and 15.5% resistant to quinolones. TMP- SMX was resistant in more than 30% of the samples in all age groups. Among quinolone-resistant isolates, resistance to cephalothin, ampicillin and sulfamethoxazole-trimethoprim was greater than 60%. Nitrofurantoin was the only antimicrobial that showed 90% of sensitivity.

CONCLUSION

The antimicrobials sensitivity profile was similar to that reported in the literature, with TMP- SMX resistance greater than 30% in the studied samples. Nitrofurantoin maintains high sensitivity rates greater than 90%. Resistance to quinolones increases proportionally with age, as well ESBL.

Presumed Urinary Tract Infection in Patients Admitted with COVID-19: Are We Treating Too Much?

Despite the low rates of bacterial co-/superinfections in COVID-19 patients, antimicrobial drug use has been liberal since the start of the COVID-19 pandemic. Due to the low specificity of markers of bacterial co-/superinfection in the COVID-19 setting, overdiagnosis and antimicrobial overprescription have become widespread. A quantitative and qualitative evaluation of urinary tract infection (UTI) diagnoses and antimicrobial drug prescriptions for UTI diagnoses was performed in patients admitted to the COVID-19 ward of a university hospital between 17 March and 2 November 2020. A team of infectious disease specialists performed an appropriateness evaluation for every diagnosis of UTI and every antimicrobial drug prescription covering a UTI. A driver analysis was performed to identify factors increasing the odds of UTI (over)diagnosis. A total of 622 patients were included. UTI was present in 13% of included admissions, and in 12%, antimicrobials were initiated for a UTI diagnosis (0.71 daily defined doses (DDDs)/admission; 22% were scored as ‘appropriate’). An evaluation of UTI diagnoses by ID specialists revealed that of the 79 UTI diagnoses, 61% were classified as probable overdiagnosis related to the COVID-19 hospitalization. The following factors were associated with UTI overdiagnosis: physicians who are unfamiliar working in an internal medicine ward, urinary incontinence, mechanical ventilation and female sex. Antimicrobial stewardship teams should focus on diagnostic stewardship of UTIs, as UTI overdiagnosis seems to be highly prevalent in admitted COVID-19 patients.

Antibiotic resistance pattern of uropathogenic Escherichia coli isolated from children with symptomatic urinary tract infection in Moscow, Russia

Background and Aim: Uropathogenic Escherichia coli (UPEC) is commonly involved in urinary tract infections (UTIs), which are generally treated with antibiotics. However, the emergence of multidrug-resistant (MDR) strains of UPEC has made the treatment difficult. There is thus a need to continuously assess their sensitivity to antibiotics. This study aimed to determine the antibiotic resistance patterns and MDR phenotypes of UPEC strains isolated from children diagnosed with UTIs at the Russian Children's Clinical Hospital in Moscow, Russia. Materials and Methods: Kirby–Bauer's disc diffusion method was used to study the sensitivity to antibiotics of 106 UPEC isolates from urine specimens from children (aged from 9 months to 18 years old) diagnosed with UTIs. The results were interpreted in accordance with the Clinical and Laboratory Standards Institute guidelines and the correlations of variables with the degree to which each antibiotic inhibited the UPEC strains in terms of diameter on the disc were determined using Spearman's rank correlation test. A t-test and principal component analysis were performed to visualize the correlations of the susceptibility of UPEC to antibiotics with the age and sex of the patients. Statistical significance was set at p≤0.05. Results: Among the 106 UPEC strains tested, none (0%) showed resistance to fosfomycin (FO), while 84 (79.2%) were resistant (R) to at least one antibiotic. The highest rates of resistance were observed to amoxicillin (69.8%), ampicillin (62.3%), cefazolin (39.6%), trimethoprim (TR) (37.7%), ceftriaxone (34.9%), and tetracycline (33.0%). Interestingly, 22 (20.8%) strains were R to imipenem. UPEC isolates from males aged 1-6 years were more R to antibiotics than those from the other groups, with the exception of TR, to which UPEC isolates from females aged 13-18 years old were less sensitive (S). The multidrug-resistance (MDR) index ranged between 0.00 and 0.75 and we found that more than a quarter of UPEC (31/106) had an MDR index ≥0.5 and only 22 (20.7%) strains were S to all antibiotics tested (MDR index=0). Finally, Spearman's rank correlation test showed that, with the exception of FO, there were correlations between the inhibition diameters of all other antibiotics. Conclusion: FO is the only antibiotic to which all UPECs were S and may be suggested as the first line of treatment for UPEC. Further research is needed to continue monitoring antibiotic resistance and to investigate the genetic features associated with such resistance observed in this study.

Oral Antibiotics in Clinical Development for Community-Acquired Urinary Tract Infections

The treatment of urinary tract infections (UTIs) has been complicated by the emergence of multidrug-resistant, β-lactamase-expressing pathogens. As a result of the limited treatment options, patients often require hospitalization and intravenous therapy. In essence, a strong unmet need for oral antibiotics, active against extended-spectrum β-lactamase (ESBL) uropathogens has emerged. Oral carbapenems (tebipenem and sulopenem) and oral cephalosporin/β-lactamase inhibitor combinations are in various stages of clinical development for the treatment of uncomplicated and complicated UTI. Tebipenem, if approved, will be the first oral treatment for complicated UTI while sulopenem will be for uncomplicated UTI. The β-lactamase inhibitors ETX0282, VNRX7145, ARX1796, and QPX7728 are combined with cefpodoxime proxetil or ceftibuten that achieve favorable exposures in urine compared to other uropathogen-active oral cephalosporins. The combination ceftibuten-QPX7728 has potential broad-spectrum coverage against carbapenemase producers including metallo β-lactamase producers. Other novel combinations, namely cefpodoxime/ETX0282, ceftibuten/VNRX-7145, and ceftibuten/ARX1796, have also demonstrated excellent activity against Klebsiella pneumoniae carbapanemase (KPC) and OXA-48-like producers. All these agents, upon their arrival for commercial use, would strengthen the outpatient therapy.

Oral cephalosporin and β-lactamase inhibitor combinations for ESBL-producing Enterobacteriaceae urinary tract infections

ESBL-producing Enterobacteriaceae as uropathogens have given rise to a sizeable amount of global morbidity. Community and hospital surveillance studies continue to report increasing proportions of these organisms as causes of urinary tract infection (UTI). Due to limited treatment options and the presence of cross-resistance amongst oral antibiotics of different classes, patients often require IV therapy, thereby increasing healthcare costs and reducing the effectiveness of delivering healthcare. Oral cephalosporin antibiotics are well known for their ability to achieve high urinary concentrations, in addition to achieving clinical success for treatment of uncomplicated UTI with a drug-susceptible pathogen. Novel cephalosporin/β-lactamase inhibitor combinations have been developed and demonstrate good in vitro activity against ESBL-producing isolates. A pooled analysis of in vitro activity of existing oral cephalosporin/clavulanate combinations in ESBL-producing Enterobacteriaceae has shown MIC50s of 0.5-1, 0.125-1 and 0.25 mg/L for cefpodoxime, ceftibuten and cefixime, respectively. A novel cyclic boronic acid β-lactamase inhibitor, QPX7728, was able to produce MIC50 values of 0.5 and ≤0.06 mg/L when paired with cefpodoxime and ceftibuten, respectively. Other novel combinations, cefpodoxime/ETX0282 and ceftibuten/VNRX7145, have also demonstrated excellent activity against ESBL producers. Clinical trials are now awaited.

Trends in antibiotic resistance for over 700,000 Escherichia coli positive urinary tract infections over six years (2014-2019) from a university teaching hospital

Introduction

Antibiotic microbial resistance (AMR) is a global health problem. Our aim was to review the resistance of Escherichia (E.coli) to antibiotics at our university hospital over a six-year period and see whether our protocol based antibiotic policy over this time led to any change in the resistance patterns.

Material and methods

Sensitivities of E.coli urine isolates between 2014–2019 (6-years) were sourced from the hospital and general practitioners in the community and collected from the microbiology department. Trends of resistance for amoxicillin, tazocin, cefalexin, ciprofloxacin, co-amoxiclav, gentamicin, nitrofurantoin, trimethoprim, amikacin, and pivmecillinam were examined using the Cochran-Armitage test.

Results

712,004 urine samples tested positive for E. coli. The overall resistance trends for cefalexin, nitrofurantoin and amikacin remained equivocal; increased for ciprofloxacin, co-amoxiclav, gentamicin, and tazocin; and decreased for fosfomycin, pivmecillinam, and trimethoprim.

Conclusions

Despite our protocol based antibiotic policy, although the overall antibiotic resistance remained stable, there was an increasing trend in antibiotic resistance for more commonly used antibiotics including ciprofloxacin, co-amoxiclav, gentamicin, and tazocin reflecting their overall use for prophylaxis and treatment. We plan to continue our policy of reviewing our antibiotic usage and the prescribing protocol with the microbiology department to minimize antibiotic resistance.

Uropathogens antibiotic susceptibility as an indicator for the empirical therapy used for urinary tract infections: a retrospective observational study

Background and Objectives

Urinary tract infection (UTI) is a common infection affects people of different ages. It is important to explore the antibiotics susceptibility of the bacterial agents to improve the empirical antibacterial prescription because of emerging of multi-drug resistant (MDR) bacteria.

Materials and Methods

This is a retrospective observational study including 322 patients with UTI at the largest hospital at the center of Al-Basrah Governorate in the far south of Iraq from August 2018 to November 2019. Bacterial isolates from urine samples with significant bacteria were investigated by automated VITEK® 2 compact system to determine the causative bacteria and their antibiotics susceptibility.

Results

Escherichia coli and Klebsiella pneumoniae were the first and second most frequent Gram-negative isolates, whereas Staphylococcus haemolyticus and Enterococcus faecalis were the first and second most frequent Gram-positive isolates. Fosfomycin, tigecycline, colistin, meropenem, imipenem, amikacin and nitrofurantoin had high susceptibility rates against Gram-negative isolates. Nitrofurantoin, tigecycline, daptomycin, teicoplanin, vancomycin and linezolid had a high effect against Gram-positive isolates.

Conclusion

The leading causative isolates especially the most predominant Gram-negative isolates E. coli and K. pneumoniae show high resistance rates against important antibiotics including penicillin/β-lactamase inhibitors piperacillin/tazobactam, ceftazidime cefepime, ciprofloxacin, levofloxacin and trimethoprim/sulfamethoxazole which call for reconsidering them for treatment of UTI.

Area of technical uncertainty for susceptibility testing of amoxicillin/clavulanate against Escherichia coli: analysis of automated system, Etest and disk diffusion methods compared to the broth microdilution reference

OBJECTIVES

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) recently warned about an area of technical uncertainty (ATU) of amoxicillin/clavulanate (AMX/C) disk susceptibility testing against members of the Enterobacterales. Thus, we aimed to compare the reliability of three routine methods and to evaluate the impact of the ATU.

METHODS

286 Escherichia coli strains (including 159 AMX-resistant strains) were categorized for the two EUCAST AMX/C breakpoints by disk diffusion (Bio-Rad), the Phoenix automated system (Becton Dickinson) and the Etest (AES) compared to the broth microdilution reference method.

RESULTS

By microdilution, 84.2% of strains were AMX/C-susceptible using the urinary breakpoint (MIC ≤32 mg/L) and 62.2% using the systemic breakpoint (MIC ≤8 mg/L), with 63.6% of MICs between 4 and 16 mg/L. For the systemic breakpoint, category agreement (CA) and very major error (VME) were unacceptable for the Etest (71.7% and 27.3%), disk (73.1% and 23.4% at 19-mm cut-off) and to a lesser extent for the Phoenix system (83.6% and 10.5%). For disks, an unacceptable VME rate was observed for diameters up to 22 mm, probably due to overcharged disks. For the Etest, VMEs were high at 6 mg/L (46/63) and 8 mg/L (22/29). For the urinary breakpoint, CA was more acceptable for disk (88.9%) and Etest (84.3%) but was unevaluable for Phoenix.

CONCLUSION

AMX/C susceptibility testing of E. coli for systemic breakpoint was unreliable with the three routine methods, explained mainly by the high prevalence (~60%) of strains with microdilution MICs around the breakpoint (8 mg/L). Our data confirmed the EUCAST 19-20-mm ATU for disk and suggest introducing ATU for Etest MIC values of 6 and 8 mg/L.

Are oral cefuroxime axetil, cefixime and cefditoren pivoxil adequate to treat uncomplicated acute pyelonephritis after switching from intravenous therapy? A pharmacokinetic/pharmacodynamic perspective

OBJECTIVES

The goal of this study is to assess, by means of pharmacokinetic/pharmacodynamic (PK/PD) analysis using the Monte Carlo simulation, the adequacy of oral cephalosporins cefuroxime axetil, cefixime and cefditoren at different dosing regimens as switch therapy after intravenous cephalosporin treatment in uncomplicated acute pyelonephritis.

METHODS

The methodology included: (i) dosing regimen selection and acquisition of pharmacokinetic data; (ii) microbiological data acquisition; and (iii) Monte Carlo simulation to estimate the PTA (probability of PK/PD target attainment) and CFR (cumulative fraction of response), as indicators of treatment success.

RESULTS

At the current susceptibility breakpoints defined by EUCAST and CLSI for either cefuroxime axetil or cefixime, the probability of bactericidal target attainment is zero for the dosage regimens simulated. Considering the bactericidal target %fT_>MIC>70%, the likelihood of the cefuroxime 500-mg q8h regimen or the cefixime 200-mg q12h regimen producing this exposure or achieving this target is only above 90% for organisms yielding MICs≤0.5mg/l and MICs≤0.25mg/l, respectively. Cefditoren pivoxil 400mg q12h provided probabilities of bactericidal target attainment of 80% or higher for MICs≤0.03mg/l, and ≤0.25mg/l if considering total instead of free drug concentrations.

CONCLUSIONS

The results of the PK/PD target attainment analysis reveal that the likelihood of treatment success based upon the current breakpoints proposed by either EUCAST or CLSI is low. Of the three cephalosporins, cefixime 400mg q12h prove to be the best option in oral APN treatment, although this regimen is currently off label.

Antibiotic Resistance Among Uropathogenic Escherichia coli

Urinary tract infections (UTIs) belong to the most common community-acquired and nosocomial infections. A main etiological factor of UTIs is uropathogenic Escherichia coli (UPEC). This review describes the current state of knowledge on the resistance of UPEC to antibiotics recommended for the treatment of UTIs based on the available literature data. Nitrofurantoin and fosfomycin are recommended as first-line therapy in the treatment of uncomplicated cystitis, and the resistance to these antimicrobial agents remains low between UPEC. Recently, in many countries, the increasing resistance is observed to trimethoprim-sulfamethoxazole, which is widely used as the first-line antimicrobial in the treatment of uncomplicated UTIs. In European countries, the resistance of UPEC to this antimicrobial agent ranges from 14.6% to 60%. The widespread use of fluoroquinolones (FQs), especially ciprofloxacin, in the outpatients is the cause of a continuous increase in resistance to these drugs. The resistance of UPEC to FQs is significantly higher in developing countries (55.5–85.5%) than in developed countries (5.1–32.0%). Amoxicillin-clavulanic acid is recommended as first line-therapy for pyelonephritis or complicated UTI. Resistance rates of UPEC to amoxicillin-clavulanic acid are regionally variable. In European countries the level of resistance to this antimicrobial ranges from 5.3% (Germany) to 37.6% (France). Increasing rates of UPEC resistance to antimicrobials indicate that careful monitoring of their use for UTI treatment is necessary.

In Vivo Pharmacodynamic Profile of Ceftibuten-Clavulanate Combination against Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae in the Murine Thigh Infection Model

Ceftibuten-clavulanate (CTB-CLA) is a novel β-lactam-β-lactamase combination with potential utility for the management of urinary tract infections caused by extended-spectrum-β-lactamase (ESBL)-producing organisms. We examined the pharmacodynamics of the combination against 25 Enterobacteriaceae expressing β-lactamases (CTX-M, TEM, and SHV wild types and SHV-ESBL) in the murine thigh infection model. MIC values of CTB and CTB-CLA ranged from 1 to >32 mg/liter and 0.125 to 8 mg/liter, respectively. Human-simulated regimens of CTB and CLA equivalent to clinical doses of 400 mg orally (p.o.) every 8 h (q8h) and 187 mg q8h, respectively, were developed. CLA dose fractionation studies were undertaken to characterize the driver of efficacy. CLA dose-ranging studies were undertaken to assess the activity of the CTB human-simulated regimen in combination with escalating CLA exposures. The relationships between the percentage of the dosing interval during which the free CLA plasma concentrations remained above a threshold concentration (%fT>C_T ) and the change in log₁₀ CFU per thigh at 24 h were examined across different threshold concentrations. Additionally, the efficacy of a human-simulated regimen of CTB-CLA was assessed against isolates with various susceptibilities to the combination. The pharmacokinetic/pharmacodynamic index that best correlated with the efficacy of the combination was %fT > threshold CLA plasma concentration of 0.5 mg/liter. The plasma %fT>0.5 mg/liter associated with the static endpoint was 20.59%. For isolates with CTB-CLA MICs of ≤4 mg/liter, stasis was achieved with a human-simulated regimen of CTB-CLA against 20/22 isolates (90.9%), while for isolates with MICs of 8 mg/liter, only 1/3 tested isolates (33.3%) displayed stasis. Results suggest a susceptibility breakpoint of 4 mg/liter for CTB-CLA. These data support the consideration of the CTB-CLA combination for the treatment of urinary tract infections due to ESBL-producing Enterobacteriaceae.

In vitro susceptibility of urinary Escherichia coli isolates to first- and second-line empirically prescribed oral antimicrobials: CANWARD surveillance study results for Canadian outpatients, 2007-2016

Escherichia coli isolates (n = 2035) from urine specimens of outpatients presenting to Canadian medical clinics and hospital emergency departments from 2007-2016 were collected as part of the CANWARD surveillance study. Isolate identification and antimicrobial susceptibility testing (AST) were performed at a central site (Health Sciences Centre, Winnipeg, Canada). AST of first- and second-line oral antimicrobial agents was performed using CLSI methods (M07, 11th ed, 2018); fosfomycin was tested by agar dilution and all other agents by broth microdilution. Minimum inhibitory concentrations (MICs) were interpreted using CLSI M100 (2018) criteria. Fosfomycin (99.2% of isolates susceptible), nitrofurantoin (97.5%) and cefalexin (93.6%) were the most active agents tested; amoxicillin/clavulanic acid (AMC) (85.6%), ciprofloxacin (83.0%) and trimethoprim/sulfamethoxazole (SXT) (77.0%) were less active. Annual percentages of isolates positive for extended-spectrum β-lactamases (ESBLs) or demonstrating multidrug-resistant (MDR) phenotypes increased from 0.8% (2007) to 10.1% (2016), and from 9.7% (2007) to 16.5% (2016), respectively, whilst the annual frequency of AmpC-positive isolates decreased from a high of 3.2% in 2008 to 0.7% in 2016. The most common MDR phenotype of E. coli was non-susceptibility to AMC, ciprofloxacin, and SXT, accounting for 12.7% (26/205) of all MDR isolates. Rates of susceptibility were higher for fosfomycin than for the five other oral agents tested against ESBL-positive (96.1% susceptible) and MDR (95.1%) isolates and were equal to nitrofurantoin (96.4%) against AmpC-positive isolates. Prudent use of antimicrobials and close monitoring of antimicrobial susceptibilities of clinical uropathogenic E. coli isolates are imperative to help preserve the utility of oral antimicrobials.

Molecular drivers of emerging multidrug resistance in Proteus mirabilis clinical isolates from Algeria

OBJECTIVES

The aim of this study was to characterise the molecular drivers of multidrug resistance in Proteus mirabilis isolated from Algerian community and hospital patients.

METHODS

A total of 166 P. mirabilis isolates were collected from two hospitals and eight private laboratories from four cities (Khemis Miliana, Aïn Defla, Oran and Chlef) located in northwestern Algeria. All isolates were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antimicrobial susceptibility testing was performed by the disk diffusion and Etest methods. Genes encoding AmpC β-lactamases, extended-spectrum β-lactamases (ESBLs), quinolone resistance and aminoglycoside-modifying enzymes (AMEs) as well as plasmid replicon typing were characterised by PCR. Clonal relationships were also determined by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) typing and were compared with MALDI-TOF/MS proteomic typing.

RESULTS

Of the 166 P. mirabilis isolates, 14 (8.4%) exhibited resistance to important antibiotics, including amoxicillin, amoxicillin/clavulanic acid, cefotaxime, gentamicin and ciprofloxacin, of which 4/14 (28.6%) had an ESBL genotype (bla_CTX-M-2) and 10 (71.4%) had an AmpC/ESBL genotype (bla_CMY-2/bla_TEM-1). AME genes were detected in all isolates, including ant(2'')-I, aac(3)-I, aac(6')-Ib-cr and aac(3)-IV. The qnrA gene was identified in 13 isolates (7.8%). ERIC-PCR showed one predominant clone, with eight bla_CMY-2-producing isolates from UHC Oran belonging to profile A clustering together in the MALDI-TOF/MS dendrogram.

CONCLUSION

Here we report the first description of AME and plasmid-mediated quinolone resistance genes among ESBL- and/or AmpC β-lactamase-producing P. mirabilis isolates from community- and hospital-acquired infections in northwestern Algeria.

Urinary infection in the elderly

INTRODUCTION

Urinary tract infections (UTIs) are one of the most frequent infections. In the elderly, they have multiple comorbidities. The objective of this work is to describe the clinical and microbiological epidemiology of elderly persons admitted for UTIs and to evaluate the suitability of empirical treatments and their implications regarding mortality.

MATERIAL AND METHODS

An observational study was conducted during 2013-2015 in 4public hospitals, with patients older than 65 years who were admitted to the Internal Medicine service with a microbiological diagnosis of UTI. Cases of asymptomatic bacteriuria were excluded. In-hospital mortality was analyzed. Univariate analysis and multivariate analysis was carried out.

RESULTS

A total of 349 episodes were selected, with a mean age of 82 ± 11 years, 51% female. Mortality was 10.3% and was associated with age, dementia and sepsis and septic shock (P<.05). The most frequent organisms were Escherichia coli(E. coli) (53.6%), Klebsiella spp. (8.7%) and Enterococcus spp. (6.6%). E. coli and Klebsiella spp. with extended-spectrum beta-lactamases (13% of the total isolated) were associated with the previous use of antibiotics, community care treatment and a permanent urinary catheter (P<.05). The empirical treatment was adequate only in 73.6% of cases. As these treatments were associated with higher mortality, they were not considered adequate.

CONCLUSIONS

In the elderly, UTIs show a high mortality. Empirical treatment is often inadequate and may be associated with increased mortality.

Stratification by demographic and clinical data of the antibiotic susceptibility of Escherichia coli from urinary tract infections of the community

Aim

To determine the patterns of antibiotic susceptibility of Escherichia coli strains isolated from adult patients with urinary tract infection (UTI), and to stratify the results by age and type of UTI to verify if there are statistically significant differences that can help physicians to prescribe better empirical antibiotherapy.

Design

Cross-sectional prospective study.

Location

Community of Getafe (Madrid). Primary care level.

Participants

100 E. coli strains, randomly chosen, isolated from the urine (10⁴–10⁵ cfu/ml) of different patients from primary care centers in the Getafe area.

Main measurements

The antibiotic susceptibility of the strains was evaluated and the results were stratified by age and type of UTI. The clinical and demographic data of the patients were analyzed, classifying each episode as complicated UTI or uncomplicated UTI.

Results

Strains isolated from patients with uncomplicated UTI showed significantly greater susceptibility than those of complicated UTI to amoxicillin (65.9% vs. 30.6%, p = 0.001), amoxicillin/clavulanic acid (95.5% vs. 77.6%, p = 0.013) and ciprofloxacin (81.8% vs. 63.3%, p = 0.047). In complicated UTI, susceptibility to ciprofloxacin was significantly greater in the ≤65 years age group compared to the older age group (78.3% vs. 50%, respectively, p = 0.041). In the rest of antibiotics, no statistically significant differences were obtained when comparing by age (≤65 years versus >65 years), both in uncomplicated and complicated UTI.

Conclusions

Clinical and demographic data of patients with UTI are of great importance in the results of the antibiotic susceptibility in E. coli. Antibiograms stratified by patient characteristics may better facilitate empirical antibiotic selection for UTI in primary care.

The prevalence of plasmid-mediated quinolone resistance and ESBL-production in Enterobacteriaceae isolated from urinary tract infections

INTRODUCTION

β-lactam and fluoroquinolone antibiotics are usually used for the treatment of urinary tract infections (UTIs). The aim of this study was to determine the prevalence of plasmid-mediated quinolone resistance (PMQR) and extended spectrum β-lactamases (ESBLs) in Enterobacteriaceae isolated from UTIs.

MATERIALS AND METHODS

Two hundred and nineteen samples of Enterobacteriaceae isolated from UTIs were collected in the Northwest of Iran. Antimicrobial susceptibility testing was determined by the disk diffusion method. ESBLs were detected by the double-disk test. ESBL and PMQR-encoding genes were screened using the polymerase chain reaction.

RESULTS

The rate of resistance to moxifloxacin, nalidixic acid, gatifloxacin, ofloxacin, ciprofloxacin, and levofloxacin in ESBL-producing isolates was 89.3%, 88%, 84%, 80%, 78.7%, and 73.3%, respectively. PMQR-producing Enterobacteriaceae isolates were identified in 67 samples (89.1%). The most prevalent PMQR genes were aac (6')-Ib-cr 120 (68.6%) followed by oqxB 72 (41.1%), oqxA 59 (33.7%), qnrB 36 (20.6%), qnrS 33 (18.9%), qnrD 19 (10.9%), qepA 13 (7.4 %), qnrA 10 (5.7%), and qnrC 9 (5.1%). There was a strong association between PMQR genes and blaCTX-M-15 and blaTEM-116 and other ESBL genes.

CONCLUSION

High resistance rates were detected to quinolones among ESBL-producing isolates from UTIs. There is a high prevalence of PMQR genes in Enterobacteriaceae in Azerbaijan and Iran, and the most common PMQR is aac(6')-Ib-cr. There is a significant association between PMQR and ESBL-producing isolates.

Multidrug-resistant infections in long-term care facilities: extended-spectrum β-lactamase-producing Enterobacteriaceae and hypervirulent antibiotic resistant Clostridium difficile

Infections due to multidrug-resistant (MDR) organisms in long-term care facilities (LTCFs) residents constitute a public health concern. This multicenter study investigated the frequency of ESBL-producing pathogens and MDR Clostridium difficile in clinical specimens from LTCF residents in Italy. During October 2014-March 2015, all urine and diarrheic fecal samples from LTCF residents (≥65 years) with suspected urinary tract infection or C. difficile infection, respectively, received for diagnosis by 4 hospital laboratories located in different cities were analyzed. Antibiotic susceptibility testing, characterization of resistance genes, and molecular typing of pathogens were performed. Of 806 urine cultures collected from 626 residents at 44 different LTCFs, 492 were positive for microbial infection. Of these, 158 were positive for at least an ESBL-producing Enterobacteriaceae species (32.1%), with Escherichia coli as the most frequent ESBL pathogen (23.4%) followed by Klebsiella pneumoniae (4.5%). Furthermore, 4 carbapenemase producers (0.8%) (1 E. coli with VIM-1and 3 K. pneumoniae with KPC-3) were detected. The CTX-M-15 type ESBL predominated in both E. coli (71.3%) and K. pneumoniae (77.3%). Most E. coli isolates (82.6%) belonged to the ST131/H30 clone/subclone. For K. pneumoniae, ST307 and ST15 were frequent (31.8% and 22.7%, respectively), but isolates harboring bla_KPC-3 belonged to CC258. Of 136 diarrheic fecal samples collected from 111 residents at 26 different LTCFs, 21 (15.4%) were positive for toxigenic C. difficile; of these, 13 (62%) were MDR (resistant to 3 or more antimicrobial agents of different classes). The predominant C. difficile polymerase chain reaction ribotype was 356/607 (42.9%), followed by 018, 449, and 078 (14% each). Public health efforts are needed to contain the diffusion of CTX-M-producing Enterobacteriaceae and MDR C. difficile in LTCF settings.

Antibiotic resistance in E. coli isolates from patients with urinary tract infections presenting to the emergency department

PURPOSE

Escherichia coli urine isolates from patients presenting to the emergency department at a German tertiary care hospital were retrospectively analyzed from January 2015-March 2017 to determine antibiotic resistance patterns and patient risk factors for resistance.

METHODS

Uncomplicated urinary tract infection (UTI) was defined as UTI in the otherwise healthy patient without relevant co-morbidities and complications. Patients were assumed to have UTI if diagnosis was made by the attending physician with conclusive dipstick results. For subgroup analysis, only patients with symptoms suggestive for UTI documented in their records were included.

RESULTS

228 patients with a UTI diagnosed by the attending physician with E. coli isolated in urine culture were included. 154/228 patients had documented symptomatic UTI, 57/154 had uncomplicated infection, 76/154 patients had cystitis, and 124/154 were female. Resistance rates of uncomplicated UTI in symptomatic patients were: ciprofloxacin 10.5%, cotrimoxazole 15.8%, amoxicillin/clavulanic acid 5.3%, nitrofurantoin 0% (CLSI MICs). Previous hospitalization in the last 3 months (including patients living in a long-term care facility) was significantly correlated with resistance to ciprofloxacin, cotrimoxazole and amoxicillin/clav. Previous hospitalization was a strong predictor of resistance to ciprofloxacin and cotrimoxazole in multivariate analysis also. Other risk factors correlated with resistance were hematological malignancy (for cotrimoxazole) and renal transplantation (for ciprofloxacin).

CONCLUSIONS

Cotrimoxazole is still an alternative for treating uncomplicated cystitis. Previous hospitalization in the last 3 months was a strong predictor of resistance to cotrimoxazole and ciprofloxacin. Other risk factors which might help guide empirical therapy are hematological malignancy and renal transplantation.

In vitro susceptibility to 19 agents other than β-lactams among third-generation cephalosporin-resistant Enterobacteriaceae recovered on hospital admission

Objectives

As part of the multicentre Antibiotic Therapy Optimisation Study, MIC values of 19 non-β-lactam agents were determined for third-generation cephalosporin-resistant Escherichia coli , Klebsiella species and Enterobacter species (3GCREB) isolates collected in German hospitals.

Methods

A total of 328 E. coli , 35 Klebsiella spp. (1 Klebsiella oxytoca and 34 Klebsiella pneumoniae ) and 16 Enterobacter spp. (1 Enterobacter aerogenes and 15 Enterobacter cloacae ) isolates were submitted to broth microdilution antimicrobial susceptibility testing with the MICRONAUT system. MICs of fluoroquinolones (levofloxacin and moxifloxacin), aminoglycosides (gentamicin, tobramycin, amikacin, streptomycin, neomycin and paromomycin), tetracyclines (tetracycline, minocycline and tigecycline), macrolides (erythromycin, clarithromycin and azithromycin) and miscellaneous agents [trimethoprim/sulfamethoxazole, chloramphenicol, nitrofurantoin, colistin and fosfomycin intravenous (iv)] were determined and reviewed against 2016 EUCAST breakpoints.

Results

The MIC of levofloxacin was >2 mg/L for 128 of 328 E. coli and 8 of 35 Klebsiella spp., but only 1 of 16 Enterobacter spp. Rates of resistance to trimethoprim/sulfamethoxazole were high (>70%), except for Enterobacter spp. Rates of resistance to colistin and fosfomycin iv were still low. About 20% of the tested isolates were resistant to chloramphenicol. Only 1 (of 328) E. coli isolate had an MIC of amikacin >16 mg/L and only 33 of 328 E. coli and 1 of 35 Klebsiella spp. had an MIC of tobramycin >4 mg/L, whereas average gentamicin MICs were in general more elevated. A tigecycline MIC >2 mg/L was only found for 1 of 16 Enterobacter spp., but in none of the E. coli or Klebsiella spp. isolates.

Conclusions

Our study gives insight into previously unreported non-β-lactam MIC distributions of 3GCREB isolates.

Evidence of antibiotic resistance in Enterobacteriales isolated from green sea turtles, Chelonia mydas on the Great Barrier Reef

This study investigated Enterobacteriales and their antimicrobial resistance in green sea turtles captured adjacent to the central Great Barrier Reef (GBR) and proximate to urban development. Cloacal swabs were taken from 73 green turtles between 2015 and 2016. A total of 154 out of 341 Gram-negative bacterial isolates were identified as Enterobacteriales that represent 16 different species from 9 different genera. The dominant isolates were Citrobacter (30.52%), Edwardsiella (21.43%) and Escherichia (12.34%). The resistance against 12 antibiotics belonging to 6 different classes was determined. The isolates showed highest resistance to β-lactam antibiotics (78.57%) followed by quinolone (50%) and tetracycline classes (46.1%). Approximately one-third (37.7%) of the isolates identified exhibited multidrug-resistance. Isolates recovered from rehabilitated turtles were significantly multidrug resistant (p<0.009) compared to isolates from other study sites. These results provide baseline information on antimicrobial resistance while revealing gaps for further research to evaluate the level of pollution in the GBR.