Epidemiology and clinical features of infections caused by extended-spectrum beta-lactamase-producing Escherichia coli in nonhospitalized patients

Molecular characterization of Escherichia coli producing extended-spectrum β-lactamase CTX-M-14 and CTX-M-28 in Mexico

The spread of ESBL-producing Escherichia coli has constantly increased in both clinical and community infections. Actually, the main ESBL reported is the CTX-M family, which is widely disseminated between the Enterobacteriaceae family. The epidemiology of the CTX-M family shows the CTX-M-15 variant dominating worldwide, followed by CTX-M-14 and CTX-M-27. The specific ESBL-producing E. coli clones included mainly the sequence types ST131, ST405, and ST648. In this report, we present the molecular characterization of ESBL-producing E. coli clinical isolates from eight hospitals in Mexico. From a collection of 66 isolates, 39 (59%) were identified as blaCTX-M-14 and blaCTX-M-27 belonging to the group CTX-M-9. We identified 25 (38%) isolates, producing blaCTX-M-28 belonging to the group CTX-M-1. blaCTX-M-2 and blaTEM-55 were identified in one isolate, respectively. Fourteen isolates (21%) were positive for blaCTX-M-14 (13%) and blaCTX-M-28 (7.3%) that were selected for further analyses; the antimicrobial susceptibility showed resistance to ampicillin (> 256 µg/mL), cefotaxime (> 256 µg/mL), cefepime (> 64 µg/mL), and ceftazidime (16 µg/mL). The ResFinder analysis showed the presence of the antimicrobial resistance genes aacA4, aadA5, aac(3)lla, sul1, dfrA17, tet(A), cmlA1, and blaTEM-1B. PlasmidFinder analysis identified in all the isolates the replicons IncFIB, which were confirmed by PCR replicon typing. The MLST analysis identified isolates belonging to ST131, ST167, ST405, and ST648. The ISEcp1B genetic element was found at 250 pb upstream of blaCTX-M-14 and flanked by the IS903 genetic element at 35 pb downstream. The IS1380-like element ISEc9 family transposase was identified at 250 pb upstream of blaCTX-M-14 and flanked downstream by the IS5/IS1182 at 80 pb. Our study highlights the significant prevalence of CTX-M-14 and CTX-M-28 enzymes as the second-most common ESBL-producing E. coli among isolates in Mexican hospitals. The identification of specific sequence types in different regions provides valuable insights into the correlation between ESBL and E. coli strains. This contribution to understanding their epidemiology and potential transmission routes is crucial for developing effective strategies to mitigate the spread of ESBL-producing E. coli in healthcare settings.

Epidemiology and clinical characteristics of patients with healthcare-acquired multidrug-resistant Gram-negative bacilli: a retrospective study from a tertiary care hospital

The numbers of infections caused by Gram-negative bacteria (GNB) that produce extended-spectrum beta-lactamases (ESBLs) and those that are carbapenem resistant, especially Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae), are increasing, and these infections are becoming a global public health problem. The aim of this study was to assess the prevalence of infections caused by ESBL-producing and carbapenem-resistant Gram-negative bacilli in patients hospitalized at An-Najah National University Hospital in Nablus, Palestine, and to provide healthcare workers with valuable information on the treatment of these infections. A retrospective cross-sectional investigation was conducted at a large tertiary care teaching hospital. The study included patients admitted to the hospital between January and December 2021, from whom ESBL-producing and carbapenem-resistant Gram-negative bacilli were isolated. The patients' clinical and demographic information was obtained from the hospital information system. In addition, information regarding the bacterial isolates and antibiotic resistance was obtained from the hospital's microbiology laboratory. This study included a total of 188 patients-91 males (48.4%) and 97 females (51.6%). The general surgical ward accounted for the highest proportion of infections (30.9%), followed by the surgical ICU (12.2%). The most common infections were caused by ESBL-producing E. coli, which accounted for 62.8% of the cases. Among them, urinary tract infections caused by this microorganism were the most prevalent (44.7% of patients). Over 50% of the patients (54.2%) had a history of antibiotic use, and 77.8% had been hospitalized within the past three months. ESBL-producing E. coli was significantly isolated from blood cultures (p-value = 0.000), and CR-K. pneumoniae was significantly isolated from endotracheal isolates (p-value = 0.001). This study emphasizes the concerning frequency of healthcare-acquired infections caused by ESBL-producing and carbapenem-resistant GNB in a tertiary care hospital. The substantial prevalence of antibiotic resistance presents considerable obstacles to the successful administration of routinely employed antibiotics. The results highlight the immediate need for improved antimicrobial stewardship and the implementation of infection control strategies to reduce the effects of multidrug-resistant GNB on patient well-being and public health.

Extended-Spectrum Beta-Lactamase Escherichia coli-Associated Acute Cholangitis: Uncommon Patient Characteristics and Clinical Implications

Acute cholangitis is a potentially life-threatening condition caused by an infection of the biliary tract resulting from biliary obstruction. This case report highlights an unusual presentation of acute cholangitis in an elderly patient characterized by the presence of extended-spectrum beta-lactamase-producing Escherichia coli. We aim to emphasize the significance of recognizing diverse clinical manifestations in the elderly population to enhance timely diagnosis and appropriate management. The case highlights the importance of better understanding patient risk factors for potential causative organisms and their susceptibility to selecting proper antibiotics and improving clinical outcomes.

Predictors for onset of extended-spectrum beta-lactamase-producing Escherichia coli-induced bacteraemia: a systematic review and meta-analysis

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli bacteraemia can induce unfavourable clinical outcomes due to delay in appropriate antimicrobial treatment and limited therapeutic options. Therefore, elucidating the predictors of ESBL-producing E. coli-induced bacteraemia is crucial to improve clinical outcomes. However, a literature search did not reveal any studies that incorporate a meta-analysis of the predictors of ESBL-producing E. coli-induced bacteraemia. As such, this review was undertaken to assess current evidence on the predictors of ESBL-producing E. coli-induced bacteraemia. PubMed, Web of Science and Cochrane Library databases were searched for all relevant publications from January 2000 to September 2021. This systematic review evaluated 10 observational studies, comprising a total of 2325 patients with E. coli-induced bacteraemia and 850 (36.6%) ESBL-producing strains. In the meta-analysis, previous antibiotic therapy [pooled risk ratio (RR) 2.72; P<0.001], especially with cephalosporins (pooled RR 4.66; P<0.001) and quinolones (pooled RR 5.47; P<0.001), and urinary catheter use (pooled RR 3.79; P<0.001) were predictive of ESBL-producing E. coli-induced bacteraemia. Antibiotic therapy for patients with the above-mentioned risk factors should be selected considering the possibility of ESBL-producing E. coli-induced bacteraemia compared with non-ESBL-producing E. coli-induced bacteraemia. It is important to elucidate whether appropriate modulation of the identified risk factors can potentially mitigate the risk of ESBL-producing E. coli-induced bacteraemia compared with non-ESBL-producing E. coli-induced bacteraemia.

Genotypic Determination of Extended Spectrum β-Lactamases and Carbapenemase Production in Clinical Isolates of Klebsiella pneumoniae in Southwest Nigeria

INTRODUCTION

Klebsiella pneumoniae is a major pathogen implicated in healthcare-associated infections. Extended-spectrum β-lactamase (ESBL) and carbapenemase-producing K. pneumoniae isolates are a public health concern. This study investigated the existence of some ESBL and carbapenemase genes among clinical isolates of K. pneumoniae in Southwest Nigeria and additionally determined their circulating clones.

MATERIALS AND METHODS

Various clinical samples from 420 patients from seven tertiary hospitals within Southwestern Nigeria were processed between February 2018 and July 2019. These samples were cultured on blood agar and MacConkey agar, and the isolated bacteria were identified by Microbact GNB 12E. All K. pneumoniae were confirmed by polymerase chain reaction (PCR) using the 16s rRNA gene. Antibiotic susceptibility testing (AST) was done on these isolates, and the PCR was used to evaluate the common ESBL-encoding genes and carbapenem resistance genes. Genotyping was performed using multi-locus sequencing typing (MLST).

RESULTS

The overall prevalence of K. pneumoniae in Southwestern Nigeria was 30.5%. The AST revealed high resistance rates to tetracyclines (67.2%), oxacillin (61.7%), ampicillin (60.2%), ciprofloxacin (58.6%), chloramphenicol (56.3%), and lowest resistance to meropenem (43.0%). All isolates were susceptible to polymyxin B. The most prevalent ESBL gene was the TEM gene (47.7%), followed by CTX-M (43.8%), SHV (39.8%), OXA (27.3%), CTX-M-15 (19.5%), CTX-M-2 (11.1%), and CTX-M-9 (10.9%). Among the carbapenemase genes studied, the VIM gene (43.0%) was most detected, followed by OXA-48 (28.9%), IMP (22.7%), NDM (17.2%), KPC (13.3%), CMY (11.7%), and FOX (9.4%). GIM and SPM genes were not detected. MLST identified six different sequence types (STs) in this study. The most dominant ST was ST307 (50%, 5/10), while ST258, ST11, ST147, ST15, and ST321 had (10%, 1/10) each.

CONCLUSION

High antimicrobial resistance in K. pneumoniae is a clear and present danger for managing infections in Nigeria. Additionally, the dominance of a successful international ST307 clone highlights the importance of ensuring that genomic surveillance remains a priority in the hospital environment in Nigeria.

Antimicrobial Activity of Tebipenem and Comparators against Enterobacterales from diverse Outpatient Centers and Nursing Homes in the United States

INTRODUCTION

Tebipenem is a potential option for the treatment of a range of infections because of its oral dosing coupled with the safety profile of the β-lactam antimicrobial class.

OBJECTIVES

To evaluate tebipenem in vitro activity against a challenge set of clinical Enterobacterales collected from outpatient and community settings.

METHODS

618 Enterobacterales isolates were submitted by 11 geographically dispersed U.S medical centers that processed cultures from affiliated outpatient centers in 2022. Susceptibility tests for tebipenem and comparator agents were performed by broth microdilution. Extended-spectrum-β-lactamase (ESBL)-like isolates were identified phenotypically. Multidrug-resistant isolates were non-susceptible to ≥1 agent in ≥3 antimicrobial classes. Genotypic testing (CarbaR) was conducted on select isolates.

RESULTS

Isolates (59% Escherichia coli) were recovered from patients seen predominantly in urology/nephrology (24%), nursing home/long-term care (21%), and ambulatory/primary care (21%) clinics. Comparator agent susceptibility rates against all isolates were as follows: levofloxacin (67.5%), amoxicillin/clavulanate (73.6%), cefixime (70.4%), cefpodoxime (70%), cephalexin (61.7%), ceftriaxone (74.4%), cefazolin (63.8%), ertapenem (97.6%), meropenem (99.7%), nitrofurantoin (64.9%), and sulfamethoxazole/trimethoprim (70.9%). Overall, 90.3% (558/619) of isolates were inhibited at a tebipenem MIC of ≤0.125 mg/L (MIC_50/90, 0.016/0.125 mg/L), including 85.7% inhibition of ESBL-phenotype isolates (n=161; MIC_50/90, 0.03/0.25 mg/L), 86.3% of levofloxacin and sulfamethoxazole/trimethoprim co-resistant isolates (n=95; MIC_50/90, 0.016/0.25 mg/L) and 84.3% of multidrug-resistant isolates (n = 172; MIC_50/90, 0.03/0.25 mg/L). Carbapenemase genes were observed in 2 ESBL-phenotype isolates with a tebipenem MIC of ≥0.5 mg/L.

CONCLUSION

Relative to common oral comparators, these data demonstrate excellent tebipenem in vitro activity against Enterobacterales isolated from patients receiving care in outpatient settings, including urology clinics and nursing homes.

Prevalence, incidence and risk factors for acquisition and colonization of extended-spectrum beta-lactamase- and carbapenemase-producing Enterobacteriaceae from dogs attended at a veterinary hospital in Spain

The last 10 years have seen a progressive increase in antibiotic resistance rates in bacteria isolated from companion animals. Exposure of individuals to resistant bacteria from companion animals, such as extended-spectrum beta-lactamase- (ESBL) and carbapenemase- (CPE) producing Enterobacteriaceae, can be propitiated. Few studies evaluate the incidence and risk factors associated with colonization by multidrug-resistant bacteria in dogs. This work aims to estimate the prevalence, incidence and risk factors associated with colonization of ESBL-E and CPE-E in 44 canine patients hospitalized in a veterinary hospital. The antimicrobial susceptibility of Enterobacteriaceae strains was analyzed and the molecular detection of resistant genes was performed. A prevalence of 25.0% and an incidence of ESBL-E of 45.5% were observed in dogs colonized by Enterobacteriaceae at hospital admission and release, respectively. Escherichia coli, Klebsiella pneumoniae, Citrobacter koseri and Morganella morganii were identified as ESBL-producing bacterial species. Resistance genes were detected for ESBL-producing strains. No CPE isolates were obtained on the CPE-selective medium. The administration of corticosteroids prior to hospitalization and the presence of concomitant diseases were associated with colonization by these bacteria in dogs. Considering that one-quarter of the patients evaluated were colonized by ESBL-E, companion animals should be considered as potential transmission vehicles and ESBL-E reservoirs for humans. Special care should be taken in animals attended at veterinary hospitals, as the length of stay in the hospital could increase the risks.

Pediatric community acquired urinary tract infections due to extended-spectrum beta-lactamase versus non-extended-spectrum beta-lactamase producing bacteria

BACKGROUND

This study aimed to evaluate the demographics, clinical characteristics, risk factors, and antibiotic resistance of pediatric community-acquired urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-producing and non-ESBL-producing uropathogens.

METHODS

This retrospective study was conducted at a tertiary care hospital in Saudi Arabia, among children aged between 0 and 14 years, with a culture-proven diagnosis of community-acquired UTI between February 2019 and September 2021. Patients were divided into two groups based on whether or not their UTI was caused by ESBL-producing bacteria.

RESULTS

A total of 383 patients with community-acquired UTI were evaluated. Escherichia coli was detected in 72.6% of cultures. Extended-spectrum beta-lactamase-producing organisms were responsible for 35.7% of UTI episodes. Of these 69% and 31% were caused by E. coli and Klebsiella pneumoniae, respectively. There were no significant differences between the two groups with regard to clinical presentation or urine analysis. The resistance rates in the ESBL-producing group were 39.4% for amoxicillin/clavulanic acid, 65.7% for ciprofloxacin, 72.3% for co-trimoxazole, 32.8% for nitrofurantoin, 21.2% for gentamicin, and 0.7% for amikacin and carbapenems. In the non-ESBL-producing group, it was 22.4% for amoxicillin/clavulanic acid, 22.4% for ciprofloxacin, 38.2% for co-trimoxazole, 23.6% for nitrofurantoin, 6.1% for gentamicin, and zero for amikacin and carbapenems. The presence of renal abnormalities (p = 0.014) and male gender (p = 0.026) were determined to be independent risk factors for ESBL UTIs.

CONCLUSIONS

Recognizing risk factors and antibiotic resistance for ESBL-producing bacteria may aid in tailoring an antibiotic regimen for pediatric patients at high risk of ESBL-UTIs.

Molecular Characterization of Extended Spectrum β-Lactamase (ESBL) and Virulence Gene-Factors in Uropathogenic Escherichia coli (UPEC) in Children in Duhok City, Kurdistan Region, Iraq

Background: The presence of extended-spectrum β-lactamase (ESBL)-producing bacteria among uropathogens is significantly increasing in children all over the world. Thus, this research was conducted to investigate the prevalence of E. coli and their antimicrobial susceptibility pattern, and both genes of ESBL-producing E. coli resistant and virulence factor in UTIs patients among children in Duhok Province, Kurdistan, Iraq. Method: a total of 67 E. coli were identified from 260 urine samples of pediatric patients diagnosed with UTIs aged (0−15 years) which were collected from Heevi Pediatric Teaching Hospital, from August 2021 to the end of February 2022. Result: a high proportion of UPEC infections at ages <5 years and the rates among girls (88%) were significantly higher than those among the boys. A wide variety of E. coli are resistant to most antibiotics, such as Amoxicillin, Ampicillin and Tetracycline, and 64% of them were positive for ESBL. Interestingly, the presence of both the ESBL marker genes (blaTEM, and blaCTX-M) as well as both virulence marker genes (pai and hly) were detected in above 90% of E. coli. Conclusion: the data illustrate an alarming increase in UPEC with ESBL production and the emergence of multidrug-resistant drugs in the early age of children. The public health sectors should further monitor the guidelines of using antibiotics in Kurdistan, Iraq.

Retrospective analysis of a large single cohort of Enterobacteriaceae producing extended-spectrum B-lactamase (E-ESBL) patients: incidence, microbiology, and mortality

We conducted a retrospective study from 2005 to 2019 to describe the epidemiology and mortality of enterobacterial producing extended-spectrum β-lactamase (E-ESBL) infections in our university hospital over a 17-year period of time. Clinical and microbiological data were extracted from different software used for continuous surveillance. Stool samples from systematic screening for E-ESBL colonization were excluded from the study. The incidence rate of infected patient was calculated by E-ESBL species and by year. A comparison of mortality rate in patients with bloodstream infections versus other types of infections was conducted using a Kaplan-Meier method survival curves. A log rank test (with a risk of 5%) was carried out. A total of 3324 patients with E-ESBL infection were included with an increased incidence density per 1000 days of hospitalization from 0.03 in 2005 to 0.47 in 2019. Escherichia coli was the most frequently isolated pathogen (64%). Global mortality rate was significantly higher with E. coli than with Klebsiella spp. and Enterobacter spp. (p < 0.001). Mortality was higher in patients with E-ESBL bloodstream infection than in patients with other type of E-ESBL infection (p < 0.001). Our study showed a significant increase of the E-ESBL incidence density over a 17-year period survey with a higher mortality in patients with E-ESBL bacteremia. This highlights the need to continue efforts to control the spread of these multi-resistant bacteria in our institution.

Epidemiology of urinary tract infection in adults caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae - a case-control study from Qatar

•

Urinary tract infection (UTI) caused by extended-spectrum beta-lactamase (ESBL)-producing organisms is a serious concern in the adult population.

•

Escherichia coli is the primary organism causing ESBL-UTI.

•

Avoiding indiscriminate use of antibiotics may reduce the incidence of ESBL-UTI.

Background

Community-acquired urinary tract infection (UTI) is the most common infection caused by extended-spectrum beta-lactamase (ESBL)-producing organisms.

Aim

to estimate the prevalence of ESBL-UTI in adults and to identify potential risk factors that may predispose to ESBL-UTI.

Methods

A retrospective study involving adult patients with UTI caused by ESBL-producing organisms was undertaken. Patients with UTI caused by non-ESBL-producing organisms represented the control group.

Results

In total, 1100 UTI isolates were included in the study, 277 of which were ESBL positive. The prevalence rate was 25.2%. The mean age of patients was 55.87 years. On univariate analysis, prior history of UTI or ESBL-UTI, invasive urological procedure within preceding 3 months, hospital admission within preceding 3 months, and exposure to antibiotics were found to be significant risk factors for ESBL-UTI. On multi-variate analysis, use of cephalosporins [adjusted odds ratio (OR) 1.61, P=0.048], previous ESBL-UTI (adjusted OR 2.67, P<0.001), and invasive urological procedure in the preceding year (adjusted OR 1.61, P=0.022) were found to be independent risk factors for ESBL-UTI.

Conclusions

In Qatar, the prevalence of ESBL-UTI in adults is modest. Recent exposure to antibiotics, previous ESBL-UTI and invasive urological procedures were found to be independent risk factors for ESBL-UTI.

Public health implications of plasmid-mediated quinolone and aminoglycoside resistance genes in Escherichia coli inhabiting a major anthropogenic river of India

Presence of antimicrobial resistance (AMR) genes in Escherichia coli inhabiting anthropogenic rivers is an important public health concern because plasmid-mediated AMR genes can easily spread to other pathogens by horizontal gene transfer. Besides β -lactams, quinolones and aminoglycosides are the major antibiotics against E. coli. In the present study, we have investigated the presence of plasmid-mediated quinolone resistance (PMQR) and aminoglycoside resistance genes in E. coli isolated from a major river of northern India. Our results revealed that majority of the strains were phenotypically susceptible for fluoroquinolones and some aminoglycosides like amikacin, netilmicin, tobramycin and gentamicin. However, 16.39% of the strains were resistant for streptomycin, 8.19% for kanamycin and 3.30% for gentamicin. Of the various PMQR genes investigated, only qnrS1 was present in 24.59% of the strains along with ISEcl2 . Aminoglycoside-resistance genes like strA-strB were found to be present in 16.39%, aphA1 in 8.19% and aacC 2 in only 3.30% of the strains. Though, no co-relation was observed between phenotypic resistance for fluorquinolones and presence of PMQR genes, phenotypic resistance for streptomycin, kanamycin and gentamicin exactly co-related with the presence of the genes strA-strB , aphA1 and aacC2 , respectively. Moreover, all the AMR genes discerned in aquatic E. coli were found to be situated on conjugative plasmids and, thus easily transferrable. Our study accentuates the importance of routine surveillance of urban rivers to curtail the spread of AMR genes in aquatic pathogens.

Circumstances of the ambulatory prescription of quinolones in Urology and opportunities for intervention

INTRODUCTION AND OBJECTIVES

Antimicrobial stewardship programmes (AMSP) seldom focus on ambulatory prescribing. Our AMSP primarily supervises in-hospital prescribing, but as we aim to include the ambulatory setting, we sought opportunities for intervention on ambulatory quinolone prescription.

MATERIALS AND METHODS

We selected the prescriptions made by urologists during 2018 for analysis, and manually checked them for adequacy.

RESULTS

We analyzed 237 prescriptions. Of 136 therapeutic prescriptions, 18.4% had no reported diagnosis and 31.6% had no reported symptoms. Most patients (60.3%) did not have any urinalysis or urine culture; among those who had, 27.7% had a urinalysis not suggestive of urinary tract infection and 67.4% had a positive culture, 83.9% of which had a suitable oral alternative to quinolones. Antimicrobial therapy was not indicated in 13.9% of cases; when it was, quinolones were considered inadequate in 67.8% of cases. Incorrect duration was found in 51.1% of cases. Forty-six prescriptions were made for prophylaxis; all of these were considered inadequate.

CONCLUSION

We found a high prevalence of inadequate ambulatory quinolone prescriptions in Urology. Many followed incomplete recordings, lack of laboratory use, or inattention to alternatives. Treatment duration and quinolone choice were frequently inadequate. Quinolone prescribing for prophylaxis was always considered inadequate. These prescribing errors could serve as a starting point for future interventions.

Spatial, Ecologic, and Clinical Epidemiology of Community-Onset, Ceftriaxone-Resistant Enterobacteriaceae, Cook County, Illinois, USA

We performed a spatial and mixed ecologic study of community-onset Enterobacteriaceae isolates collected from a public healthcare system in Cook County, Illinois, USA. Individual-level data were collected from the electronic medical record and census tract–level data from the US Census Bureau. Associations between individual- and population-level characteristics and presence of ceftriaxone resistance were determined by logistic regression analysis. Spatial analysis confirmed nonrandom distribution of ceftriaxone resistance across census tracts, which was associated with higher percentages of Hispanic, foreign-born, and uninsured residents. Individual-level analysis showed that ceftriaxone resistance was associated with male sex, an age range of 35–85 years, race or ethnicity other than non-Hispanic Black, inpatient encounter, and percentage of foreign-born residents in the census tract of isolate provenance. Our findings suggest that the likelihood of community-onset ceftriaxone resistance in Enterobacteriaceae is influenced by geographic and population-level variables. The development of effective mitigation strategies might depend on better accounting for these factors.

Mechanisms of Resistance in Gram-Negative Urinary Pathogens: From Country-Specific Molecular Insights to Global Clinical Relevance

Urinary tract infections (UTIs) are the most frequent hospital infections and among the most commonly observed community acquired infections. Alongside their clinical importance, they are notorious because the pathogens that cause them are prone to acquiring various resistance determinants, including extended-spectrum beta-lactamases (ESBL); plasmid-encoded AmpC β-lactamases (p-AmpC); carbapenemases belonging to class A, B, and D; qnr genes encoding reduced susceptibility to fluoroquinolones; as well as genes encoding enzymes that hydrolyse aminoglycosides. In Escherichia coli and Klebsiella pneumoniae, the dominant resistance mechanisms are ESBLs belonging to the CTX-M, TEM, and SHV families; p-AmpC; and (more recently) carbapenemases belonging to classes A, B, and D. Urinary Pseudomonas aeruginosa isolates harbour metallo-beta-lactamases (MBLs) and ESBLs belonging to PER and GES families, while carbapenemases of class D are found in urinary Acinetobacter baumannii isolates. The identification of resistance mechanisms in routine diagnostic practice is primarily based on phenotypic tests for the detection of beta-lactamases, such as the double-disk synergy test or Hodge test, while polymerase chain reaction (PCR) for the detection of resistance genes is mostly pursued in reference laboratories for research purposes. As the emergence of drug-resistant bacterial strains poses serious challenges in the management of UTIs, this review aimed to appraise mechanisms of resistance in relevant Gram-negative urinary pathogens, to provide a detailed map of resistance determinants in Croatia and the world, and to discuss the implications of these resistance traits on diagnostic approaches. We summarized a sundry of different resistance mechanisms among urinary isolates and showed how their prevalence highly depends on the local epidemiological context, highlighting the need for tailored interventions in the field of antimicrobial stewardship.

Antimicrobial Resistance Patterns and Dynamics of Extended-Spectrum β-Lactamase-Producing Uropathogenic Escherichia coli in Cusco, Peru

Urinary tract infections (UTIs) are a common human infection. Antibiotic resistance in extended-spectrum β-lactamase (ESBL)-producing uropathogenic E. coli (UPEC) is a major therapeutic challenge due to limited treatment alternatives. The aim was to characterize the antimicrobial resistance (AMR) and dynamics of ESBL-producing UPEC isolates from UTI cases seen at a local hospital in Cusco, Peru. Ninety-nine isolates from respective patients were characterized against 18 different antibiotics. Latent class analysis (LCA) was used to evaluate the dynamics across the study time according to resistance patterns. The median age of patients was 51 years old, and nearly half were women. ESBL-producing UPEC isolates were slightly more frequent in outpatient services than emergency rooms, and there were higher resistance rates in males compared to females. Half of the ESBL producers were resistant to aminoglycosides and nitrofurantoin. Cefoxitin and fosfomycin resistance was 29.3% and 14.1%, respectively. Resistance to carbapenems was not observed. All isolates were multidrug-resistant bacteria, and 16.2% (16/99) were also classified as extensively drug-resistant bacteria. The resistance patterns varied across the study time and differed regarding sex and healthcare service. The study revealed high levels of AMR to commonly used antimicrobials and a dynamic circulation of ESBL-producing UPEC isolates with varying resistance patterns.

Impact of Prior Antibiotic Use in Primary Care on Escherichia coli Resistance to Third Generation Cephalosporins: A Case-Control Study

Research is lacking on the reversibility of antimicrobial resistance (AMR). Thus, we aimed to determine the influence of previous antibiotic use on the development and decay over time of third generation cephalosporin (3GC)-resistance of E. coli. Using the database of hospital laboratories of the Autonomous Province of Bolzano/Bozen (Italy), anonymously linked to the database of outpatient pharmaceutical prescriptions and the hospital discharge record database, this matched case-control study was conducted including as cases all those who have had a positive culture from any site for 3GC resistant E. coli (3GCREC) during a 2016 hospital stay. Data were analyzed by conditional logistic regression. 244 cases were matched to 1553 controls by the date of the first isolate. Male sex (OR 1.49, 95% CI 1.10–2.01), older age (OR 1.11, 95% CI 1.02–1.21), the number of different antibiotics taken in the previous five years (OR 1.20, 95% CI 1.08–1.33), at least one antibiotic prescription in the previous year (OR 1.92, 95% CI 1.36–2.71), and the diagnosis of diabetes (OR 1.57, 95% CI 1.08–2.30) were independent risk factors for 3GCREC colonization/infection. Patients who last received an antibiotic prescription two years or three to five years before hospitalization showed non-significant differences with controls (OR 0.97, 95% CI 0.68–1.38 and OR 0.85, 95% CI 0.59–1.24), compared to an OR of 1.92 (95% CI 1.36–2.71) in those receiving antibiotics in the year preceding hospitalization. The effect of previous antibiotic use on 3GC-resistance of E. coli is highest after greater cumulative exposure to any antibiotic as well as to 3GCs and in the first 12 months after antibiotics are taken and then decreases progressively.

Subtyping β-lactamase-producing Escherichia coli strains isolated from patients with UTI by MLVA and PFGE methods

OBJECTIVES

Strain subtyping is an important epidemiological tool to trace contamination, determine clonal relationships between different strains, and the cause of outbreaks. Current subtyping methods, however, yield less than optimal subtype discrimination. Pulsed-field gel electrophoresis is the gold standard method for Escherichia coli and Multiple-Locus Variable-number tandem repeat Analysis is a rapid PCR-based method. The purpose of this study was to evaluate MLVA and PFGE methods for subtyping β -lactamase-producing E. coli strains isolated from urinary tract infections.

MATERIALS AND METHODS

Overall, 230 E. coli isolates from patients with urinary tract infections were examined for antimicrobial susceptibility testing. 10-loci and 7-loci MLVA and PFGE methods were used for molecular typing of β -lactamase-producing E. coli isolates.

RESULTS

Out of 230 isolates, 130 (56.5%) β -lactamase-producing E. coli isolates were found in this study. The diversity indices of the VNTR loci showed an average diversity of 0.48 and 0.54 for 7-loci and 10-loci MLVA, respectively. The discriminatory power of PFGE showed a value of 0.87. The discordance between the methods was high.

CONCLUSION

Our study showed that PFGE is more discriminatory than MVLA. MLVA is a PCR- based method and can generate unmistakable data, in contrast to PFGE. Optimization of polymorphic VNTR is essential to improve the discriminatory power of MLVA based on geographical region.

High Prevalence of Drug Resistance and Class 1 Integrons in Escherichia coli Isolated From River Yamuna, India: A Serious Public Health Risk

Globally, urban water bodies have emerged as an environmental reservoir of antimicrobial resistance (AMR) genes because resistant bacteria residing here might easily disseminate these traits to other waterborne pathogens. In the present study, we have investigated the AMR phenotypes, prevalent plasmid-mediated AMR genes, and integrons in commensal strains of Escherichia coli, the predominant fecal indicator bacteria isolated from a major urban river of northern India Yamuna. The genetic environment of bla_CTX–M–15 was also investigated. Our results indicated that 57.5% of the E. coli strains were resistant to at least two antibiotic classes and 20% strains were multidrug resistant, i.e., resistant to three or more antibiotic classes. The multiple antibiotic resistance index of about one-third of the E. coli strains was quite high (>0.2), reflecting high contamination of river Yamuna with antibiotics. With regard to plasmid-mediated AMR genes, bla_TEM–1 was present in 95% of the strains, followed by qnrS1 and armA (17% each), bla_CTX–M–15 (15%), strA-strB (12%), and tetA (7%). Contrary to the earlier reports where bla_CTX–M–15 was mostly associated with pathogenic phylogroup B2, our study revealed that the CTX-M-15 type extended-spectrum β-lactamases (ESBLs) were present in the commensal phylogroups A and B1, also. The genetic organization of bla_CTX–M–15 was similar to that reported for E. coli, isolated from other parts of the world; and ISEcp1 was present upstream of bla_CTX–M–15. The integrons of classes 2 and 3 were absent, but class 1 integron gene intI1 was present in 75% of the isolates, denoting its high prevalence in E. coli of river Yamuna. These evidences indicate that due to high prevalence of plasmid-mediated AMR genes and intI1, commensal E. coli can become vehicles for widespread dissemination of AMR in the environment. Thus, regular surveillance and management of urban rivers is necessary to curtail the spread of AMR and associated health risks.

Characterization of predictors of ESBL-producing enterobacteriaceae in urine cultures of emergency department patients

STUDY OBJECTIVE

With increasing prevalence of extended-spectrum beta-lactamase-producing enterobacteriaceae (ESBLE), more reliable identification of predictors for ESBLE urinary tract infection (UTI) in the emergency department (ED) is needed. Our objective was to evaluate risk factors and their predictive ability for ED patients with ESBLE UTI.

METHODS

This was a retrospective case-control study at an urban academic medical center. Microbiology reports identified adult ED patients with positive urine cultures from 2015-2018. Inclusion criteria were diagnosis of UTI with monomicrobial enterobacteriaceae culture growth. Exclusions were cultures with carbapenemase-resistant enterobacteriaceae or urinary colonization. Collected variables included demographics, comorbidities, and recent medical history. Patient disposition, urine culture susceptibilities, presence of ESBLE, empiric antibiotics, and therapy modifications were collected. Patients were stratified based on ESBLE status and analyzed via descriptive statistics. The data were divided into 2 parts: the first used to identify possible predictors of ESBLE UTI and the second used to validate an additive scoring system.

RESULTS

Of 466 patients, 16.3% had ESBLE urine culture growth and 83.7% did not; 39.5% of ESBLE patients required antibiotic therapy modification, as compared to 6.4% of ESBLE negative patients (odds ratio [OR] 9.5; confidence interval [CI] 8.9-10.1). Independent predictors of ESBLE UTI were IV antibiotics within 1 year (OR 5.4; CI 2.1-12.8), surgery within 90 days (OR 6.4; CI 1.5-27.8), and current refractory UTI (OR 8.5; CI 2.0-36.6).

CONCLUSION

Independent predictors of ESBLE UTI in emergency department patients included IV antibiotics within 1 year, surgery within 90 days, and current refractory UTI.

Spread of Antimicrobial-Resistant Salmonella from Poultry to Humans in Thailand

Food animal production is important for every country. Several antibiotic agents are used in poultry farming to reduce the economic losses arising from mostly untested infectious diseases. This continued study was performed to determine the prevalence of antibiotic-resistant Salmonella in broiler chickens, poultry farmers, and Salmonella bacteremia patients. A total of 121 Salmonella isolates were collected from the Thai provinces of Khon Kaen (65 isolates), Ratchaburi (43 isolates), and Phayao (13 isolates). Salmonella from chicken showed a high rate of resistance to nalidixic acid and tetracycline. Sixty-four percent of Salmonella isolates carried class 1 integrons (intI1 gene-positive). Among the 121 Salmonella isolates, there were 15 serotypes, with S. Enteritidis being the most common. A clonal relationship between the chicken and human isolates was demonstrated by 3 molecular typing methods: enterobacterial repetitive intergenic consensus polymerase chain reaction; pulsed-field gel electrophoresis; and high-throughput multilocus sequence typing. A spread of the sequence type 11 clone was found between chickens and humans. This study revealed a large-scale Salmonella outbreak in Thailand, a link between resistant bacteria from poultry farms and vertical transmission through the food chain, and horizontal transmission of resistance genes. These results can be used for future surveillance and monitoring.

Towards the Identification of Antibiotic-Resistant Bacteria Causing Urinary Tract Infections Using Volatile Organic Compounds Analysis-A Pilot Study

Antibiotic resistance is an unprecedented threat to modern medicine. The analysis of volatile organic compounds (VOCs) from bacteria potentially offers a rapid way to determine antibiotic susceptibility in bacteria. This study aimed to find the optimal conditions to obtain the maximum number of VOCs detected which next allowed the assessment of differences in VOC profiles between susceptible and resistant isolates of Escherichia coli causing urinary tract infections. The analysis of VOCs in the headspace above the bacterial cultures allowed the distinguishing of resistant and susceptible bacteria based on the abundance of six VOCs with 85.7% overall accuracy. The results of this preliminary study are promising, and with development could lead to a practical, faster diagnostic method for use in routine microbiology.

What are the origins of growing microbial resistance? Both Lamarck and Darwin were right

INTRODUCTION

Microorganisms of clinical importance frequently develop resistance to drug therapy, now a growing problem. The experience with Mycobacterium tuberculosis is a representative example of increasing multi-drug resistance. To avoid reaching a crisis in which patients could be left without adequate treatment, a new strategy is needed. Anti-microbial therapy has historically targeted the mechanisms rather than origin of drug resistance, thus allowing microorganisms to adapt and survive.

AREAS COVERED

This contribution analyses the historical development (1943-2020) of the evolution of multi-drug resistance by M. tuberculosis strains in light of Darwin's and Lamarck's theories of evolution.

EXPERT OPINION

Regarding the molecular origin of microbial drug resistance, genetic mutations and epigenetic modifications are known to participate. The analysis of the history of drug resistance by M. tuberculosis evidences a gradual development of resistance to some antibiotics, undoubtedly due to random mutations together with natural selection based on environmental pressures (e.g., antibiotics), representing Darwin's idea. More rapid adaptation of M. tuberculosis to new antibiotic treatments has also occurred, probably because of heritable acquired characteristics, evidencing Lamarck's proposal. Therefore, microbial infections should be treated with an antibiotic producing null or low mutagenic activity along with a resistance inhibitor, preferably in a single medication.

The Continuing Plague of Extended-Spectrum β-Lactamase Producing Enterbacterales Infections: An Update

Antimicrobial resistance is a common iatrogenic complication of modern life and medical care. One of the most demonstrative examples is the exponential increase in the incidence of extended-spectrum β-lactamases (ESBLs) production among Enterobacteriaceae, that is, the most common human pathogens outside of the hospital setting. Infections resulting from ESBL-producing bacteria are associated with devastating outcomes, now affecting even previously healthy individuals. This poses an enormous burden and threat to public health. This article aims to narrate the evolving epidemiology of ESBL infections and highlights current challenges in terms of management and prevention of these common infections.

Molecular characterization and antimicrobial susceptibility of bacterial isolates present in tap water of public toilets

BACKGROUND

The present study was carried out to investigate the tap water quality of public toilets in Amritsar, Punjab, India.

METHODS

Water samples from the taps of the public toilets were collected in sterile containers and physicochemical and bacteriological analysis was performed using standard methods. Also, genotypic and phenotypic characterization of the bacterial isolates was performed using different biochemical tests and 16S ribosomal RNA analysis. An antibiotic susceptibility test was performed using antibiotics based on their mode of action. A biofilm assay was performed to assess the adhesion potential of the isolates.

RESULTS

A total of 25 bacterial isolates were identified from the water samples, including Acinetobacter junii, Acinetobacter pittii, Acinetobacter haemolyticus, Bacillus pumilus, Bacillus megaterium, Bacillus marisflavi, Bacillus flexus, Bacillus oceanisediminis, Pseudomonas otitidis, Pseudomonas sp. RR013, Pseudomonas sp. RR021, Pseudomonas sp. RR022, Escherichia coli and Enterobacter cloacae. The results of the antimicrobial susceptibility test revealed that the antibiotics cefodroxil, aztreonam, nitrofurantoin, cefepime, ceftazidime and amoxyclav were found to be mostly ineffective against various isolates. The biofilm assay revealed the weak, moderate and strong biofilm producers among them.

CONCLUSIONS

The tap water in the public toilets was microbially contaminated and needs to be monitored carefully. The antibiotic susceptibility profile showed that of 25 bacterial isolates, 5 were multidrug resistant. Bacterial isolates exhibited strong to weak adhesion potential in the biofilm assay.

Multidrug-Resistant Gram-Negative Bacteria Decolonization in Immunocompromised Patients: A Focus on Fecal Microbiota Transplantation

Antimicrobial resistance is an important issue for global health; in immunocompromised patients, such as solid organ and hematological transplant recipients, it poses an even bigger threat. Colonization by multidrug-resistant (MDR) bacteria was acknowledged as a strong risk factor to subsequent infections, especially in individuals with a compromised immune system. A growing pile of studies has linked the imbalance caused by the dominance of certain taxa populating the gut, also known as intestinal microbiota dysbiosis, to an increased risk of MDR bacteria colonization. Several attempts were proposed to modulate the gut microbiota. Particularly, fecal microbiota transplantation (FMT) was successfully applied to treat conditions like Clostridioides difficile infection and other diseases linked to gut microbiota dysbiosis. In this review we aimed to provide a look at the data gathered so far on FMT, focusing on its possible role in treating MDR colonization in the setting of immunocompromised patients and analyzing its efficacy and safety.

Prevalence and associated factors for carriage of Enterobacteriaceae producing ESBLs or carbapenemase and methicillin-resistant Staphylococcus aureus in Hong Kong community

OBJECTIVES

We conducted a cross-sectional study in Hong Kong community to estimate the carriage prevalence, associated factors and genotypes of extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBL-E), methicillin-resistant Staphylococcus aureus (MRSA) and carbapenemase-producing Enterobacteriaceae (CPE).

METHODS

Seemingly healthy subjects were asked to provide nasal, handprint and stool samples from March to April 2017. Isolates were characterized by molecular methods. We used multivariable logistic regression models within a generalized estimating equation framework to identify risk factors for ESBL-E carriage. Characteristics of MRSA/CPE carriage were summarized.

RESULTS

The prevalence of ESBL-E, MRSA and CPE were 52.8% (104/197), 2.5% (5/197) and 0.5% (1/197) respectively. Most ESBL-E isolates were E. coli (85.6%; 113/132). Most ESBL genes belonged to bla_CTX-M-G9 (68.9%) and bla_TEM (53.0%) types. Self-reported antibiotic consumption (≥2 courses) in the past six months was associated with ESBL-E carriage (adjusted odds ratio: 4.71-5.47).

CONCLUSIONS

Abundance of ESBL-E in the community are causes of concern, and antibiotic use is associated with its carriage. Presence of MRSA and CPE in community members without clear healthcare exposure hints on a change in their epidemiology. This study establishes a baseline to formulate infection control policies and future studies in combating antimicrobial resistance.

Treatment Failure in Urinary Tract Infections: A Warning Witness for Virulent Multi-Drug Resistant ESBL- Producing Escherichia coli

Background

Global increase in the prevalence of virulent extended-spectrum beta-lactamase (ESBL)-producing uropathogenic Escherichia coli (UPEC), which is also multi-drug resistant (MDR), leads to increase in severity of urinary tract infections (UTIs), decrease in the efficacy of the first-line antibiotics, and therefore increase in the morbidity and mortality rates.

Methods

We investigated the distribution of ESBL-producing UPEC in 78 E. coli isolates from community-acquired UTI patients in southern Iran. The prevalence of three major ESBL genes, antimicrobial resistance patterns against 15 conventional antibiotic disks, and the presence of 11 important virulence genes that involve in the development and progression of UTIs were evaluated in these isolates.

Results

Of the UPECs, 34.6% were ESBL-positive and 96.3% of the ESBL-producers were MDR. Among the ESBL-producers, 100% harbored bla_CTX-M, 63% harbored bla_SHV, and 11.1% harbored bla_TEM genes. ESBL-producers showed a higher level of resistance to the tested cephalosporins, fluoroquinolones, trimethoprim-sulfamethoxazole, and tetracycline than non-ESBL producers. All isolates were resistant to the tested penicillins. Prevalence of resistance to about two-third of the tested antibiotics was higher than 50% and 93.6% of the isolates were MDR. High prevalence of virulence factors particularly the adhesins (82.1% csgA, 73.1% fimH genes) and siderophore (73.1% sitA gene) was seen in the UPECs. But fortunately in MDR isolates, the virulence score and prevalence of hemagglutinin (tsh), hemolysin toxin (hlyD) and invasin (ibeA) genes were lower than in non-MDR UPECs. Shockingly, among the 15 common antibiotics, only nitrofurantoin (<20% resistance) could be recommended as an appropriate drug for the treatment of UTIs due to our ESBL-producer UPECs.

Conclusion

The alarming level of virulent MDR ESBL-producer E. coli strains in this study necessitates the performing of an antibiotic stewardship program, regional screening of ESBL-producers and their virulence properties to select appropriate antibiotic, or designing new therapeutic methods for UTIs by inactivation of the essential virulence factors of UPECs.

Quantifying risk of disease due to extended-spectrum β-lactamase producing Enterobacteriaceae in patients who are colonized at ICU admission

BACKGROUND

The prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) has globally increased and spread to the community. No clinical score is available to select carriers in whom these organisms can be empirically targeted at ICU admission.

METHODS

We prospectively assessed between 2009 and 2017 the prevalence of ESBL-PE infection in carriers at ICU admission. A logistic regression was used to determine independent risk factors associated with ESBL-PE infection, and to build a clinical risk score.

RESULTS

Of the 8,061 admissions over the study 7-year period, 745 (9%) patients were ESBL-PE carriers at admission, of whom 395 had infections at ICU admission including 59 (15%) who had culture-proven ESBL-PE related infection. By multivariable analysis, age >60 years, cirrhosis, being on broad-spectrum antibiotics within the past three months, urinary or intra-abdominal source of infection, and the absence of chronic pulmonary disease, were the five independent factors associated with ESBL-PE infection in carriers. A clinical risk score ranging from 0 to 7 was built based on these variables, with an area under the receiver operating characteristic curve (ROC) of 0.82 (95% CI 0.78-0.86); p <0.001. The prevalence of ESBL-PE infection for clinical risk scores of 0-1, 2-3, 4-5, or 6-7 was 0%, 4%, 26%, and 49%, respectively. The negative predictive value when Mondor ESBL risk score is <4 was 97%.

CONCLUSION

ESBL-PE related infection was not common in carriers at ICU admission. A clinical risk score may spare ESBL-PE carriers with lower risk of ESBL-PE infection at ICU admission unnecessary empiric carbapenem therapy.

Extended spectrum β-lactamase producing uropathogenic Escherichia coli and the correlation of biofilm with antibiotics resistance in Nepal

BACKGROUND

Urinary tract infection (UTI) is one of the frequently diagnosed infectious diseases which is caused mainly by Escherichia coli. E. coli confers resistance against the two major classes of antibiotics due to the production of extended spectrum β-lactamase enzymes (ESBL), biofilm, etc. Biofilm produced by uropathogenic E. coli (UPEC) protects from host immune system and prevent entry of antimicrobial compounds. The main objective of this cross-sectional study was to determine the correlation of biofilm production and antibiotic resistance as well as to characterize the pgaA and pgaC genes responsible for biofilm formation among uropathogenic ESBL producing E. coli.

METHODS

A total of 1977 mid-stream urine samples were examined and cultured for bacterial strain identification. ESBL was detected by combined disc method following CLSI whereas biofilm formation was analyzed by semi-quantitative method. Furthermore, the pgaA and pgaC genes responsible for biofilm formation in UPEC were detected by multiplex PCR. All the statistical analyses were done via IBM SPSS Statistics 21 where Pearson's correlation test were used to determine correlation (-1 ≥ r ≤ 1).

RESULTS

E. coli was the predominant causative agent, which accounted 159 (59.3%) of the Gram-negative bacteria, where 81 (50.9%) E. coli strains were found to be ESBL producers. In addition, 86 (54.1%) E. coli strains were found to be biofilm producers. Both the pgaA and pgaC genes were detected in 45 (93.7%) the UPEC isolates, which were both biofilm and ESBL producers. Moreover, there was a positive correlation between biofilm and ESBL production.

CONCLUSION

The analyses presented weak positive correlation between biofilm and ESBL production in which biofilm producing UPEC harbors both pgaA and pgaC genes responsible for biofilm formation.

Household carriage and acquisition of extended-spectrum β-lactamase-producing Enterobacteriaceae: A systematic review

OBJECTIVE

The epidemiology of ESBL-producing Enterobacteriaceae (ESBL-PE) has been extensively studied in hospitals, but data on community transmission are scarce. We investigated ESBL-PE cocarriage and acquisition in households using a systematic literature review.

METHODS

We conducted a systematic literature search to retrieve cross-sectional or cohort studies published between 1990 and 2018 evaluating cocarriage proportions and/or acquisition rates of ESBL-PE among household members, without language restriction. We excluded studies focusing on animal-to-human transmission or conducted in nonhousehold settings. The main outcomes were ESBL-PE cocarriage proportions and acquisition rates, stratified according to phenotypic or genotypic assessment of strain relatedness. Cocarriage proportions of clonally related ESBL-PE were transformed using the double-arcsine method and were pooled using a random-effects model. Potential biases were assessed manually.

RESULTS

We included 13 studies. Among 863 household members of ESBL-PE positive index cases, prevalence of ESBL-PE cocarriage ranged from 8% to 37%. Overall, 12% (95% confidence interval [CI], 8%-16%) of subjects had a clonally related strain. Those proportions were higher for Klebsiella pneumoniae (20%-25%) than for Escherichia coli (10%-20%). Acquisition rates of clonally related ESBL-PE among 180 initially ESBL-PE-free household members of a previously identified carrier ranged between 1.56 and 2.03 events per 1,000 person weeks of follow-up. We identified multiple sources of bias and high heterogeneity (I2, 70%) between studies.

CONCLUSIONS

ESBL-PE household cocarriage is frequent, suggesting intrafamilial acquisition. Further research is needed to evaluate the risk and control of ESBL-PE household transmission.

Preparation and Evaluation of the ZnO NP-Ampicillin/Sulbactam Nanoantibiotic: Optimization of Formulation Variables Using RSM Coupled GA Method and Antibacterial Activities

Nanoparticles (NPs) possessing antibacterial activity represent an effective way of overcoming bacterial resistance. In the present work, we report a novel formulation of a nanoantibiotic formed using Ampicillin/sulbactam (Ams) and a zinc oxide nanoparticle (ZnO NP). 'ZnO NP-Ams' nanoantibiotic formulation is optimized using response surface methodology coupled genetic algorithm approach. The optimized formulation of nanoantibiotic (ZnO NP: 49.9 μg/mL; Ams: 33.6 μg/mL; incubation time: 27 h) demonstrated 15% enhanced activity compared to the unoptimized formulation against K. pneumoniae. The reactive oxygen species (ROS) generation was directly proportional to the interaction time of nanoantibiotic and K. pneumoniae after the initial lag phase of ~18 h as evident from 2'-7'-Dichlorodihydrofluorescein diacetate assay. A low minimum inhibitory concentration (6.25 μg/mL) of nanoantibiotic formulation reveals that even a low concentration of nanoantibiotic can prove to be effective against K. pneumoniae. The importance of nanoantibiotic formulation is also evident by the fact that the 100 μg/mL of Ams and 25 µg of ZnO NP was required individually to inhibit the growth of K. pneumonia, whereas only 6.25 μg/mL of optimized nanoantibiotic formulation (ZnO NP and Ams in the ratio of 49.9: 33.6 in μg/mL and conjugation time of 27 h) was needed for the same.

Risk factors associated with prolonged intestinal colonization of ESBL-producing Enterobacteriaceae - a prospective cohort study

Background

Extended spectrum β-lactamase-producing Enterobacteriaceae (EPE) are responsible for a major part of the widespread antimicrobial resistance (AMR). Increased understanding of risk factors associated with intestinal colonization of EPE is crucial to implement adequate actions against AMR. The aim of this study was to define potential risk factors for prolonged intestinal colonization with EPE. A secondary aim was to analyze if patients were adequately informed about being infected or colonized by antibiotic-resistant bacteria.

Methods

Patients with a positive clinical EPE culture from urine, blood or feces were recruited in a region in the south of Sweden. Selective EPE fecal cultures were obtained at least three months after the initial positive culture. Prolonged intestinal colonization was defined as the prevalence of any EPE in the follow-up fecal sample. Risk factors for prolonged intestinal colonization were evaluated by using a questionnaire and by retrospective review of medical records. A univariate model and a multivariate regression analysis were performed to identify possible risk factors for intestinal EPE colonization.

Results

Out of 143 patients included in the study, 57% remained positive for EPE at the second sampling. In a multivariate regression model, urological intervention, history of EPE infection and travel to Africa and/or Asia within 2 years were found to be significantly associated with prolonged intestinal colonization of EPE. Before being approached by us, 50% of patients displayed inadequate knowledge of EPE infection or colonization.

Conclusion

In this prospective cohort study, urological intervention within 6 months and a history of EPE infection are independently associated with prolonged intestinal colonization with EPE. In contrast, travel to Africa and/or Asia within 2 years is associated with a decreased risk of prolonged intestinal colonization with EPE. There is room for improvement when it comes to patient information regarding EPE to decrease of spread.

Direct Measurement of Performance: A New Era in Antimicrobial Stewardship

For decades, the performance of antimicrobial stewardship programs (ASPs) has been measured by incidence rates of hospital-onset Clostridioides difficile and other infections due to multidrug-resistant bacteria. However, these represent indirect and nonspecific ASP metrics. They are often confounded by factors beyond an ASP’s control, such as changes in diagnostic testing methods or algorithms and the potential of patient-to-patient transmission. Whereas these metrics remain useful for global assessment of healthcare systems, antimicrobial use represents a direct metric that separates the performance of an ASP from other safety and quality teams within an institution. The evolution of electronic medical records and healthcare informatics has made measurements of antimicrobial use a reality. The US Centers for Disease Control and Prevention’s initiative for reporting antimicrobial use and standardized antimicrobial administration ratio in hospitals is highly welcomed. Ultimately, ASPs should be evaluated based on what they do best and what they can control, that is, antimicrobial use within their own institution. This narrative review critically appraises existing stewardship metrics and advocates for adopting antimicrobial use as the primary performance measure. It proposes novel formulas to adjust antimicrobial use based on quality of care and microbiological burden at each institution to allow for meaningful inter-network and inter-facility comparisons.

Risk factors for community acquired urinary tract infections caused by extended spectrum β-lactamase (ESBL) producing Escherichia coli in children: a case control study

Background: We noted a recent increase in cases of urinary tract infection due to community-acquired ESBL-producing Escherichia coli in children treated at our institution. Risk factors of urinary tract infection due to ESBL-producing E. coli in children in the USA remain unclear. Methods: A single center retrospective case control study of UTI due to CA-ESBL-producing E. coli during a 5-year period (2012-2016). Control cases with non-ESBL-producing E. coli urinary tract infection were matched by age, gender and year of infection. Results: A total of 111 patients with ESBL-producing E coli urinary tract infection and 103 controls were included. The proportion of ESBL-producing E coli urinary tract infection ranged from 7% to 15% of all UTI cases. The distribution of ESBL cases per year: 27 in 2012; 18 in 2013; 22 in 2014; 15 in 2015 and 29 in 2016. Median age was 4 years with female predominance (84%). The ESBL group was predominantly African American (32%) followed by individuals of Middle Eastern ethnic background (31%). Risk factors by univariate analysis were vesicoureteral reflux: (20.9 ESBL group vs 6% controls; p = .002), prior antibiotic usage in the last 3 months (including β-lactams), prior UTI (last 3 months), recent hospitalization (last 3 months) and Middle Eastern ethnic background. However, multivariate analysis showed that only prior antibiotic usage (p = .001) and Middle Eastern ethnic background (p < .001) were independent risk factors. ESBL-producing strains were more frequently resistant to trimethoprim-sulfamethoxazole (72% vs 25%) and ciprofloxacin (73% vs 5%) than strains not producing ESBL. Conclusion: Risk factors for community-acquired ESBL-producing E coli urinary tract in our pediatric patient population were antibiotic usage within the previous 3 months and Middle Eastern ethnic background. This may be related to increased risk of intestinal colonization with resistant bacterial strains.

Risk factors for community-onset urinary tract infections caused by extended-spectrum β-lactamase-producing Escherichia coli

Background/aim

Community-onset urinary tract infections(UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli have increased in many parts of the world. This study aimed to determine the prevalence and risk factors for community-onset UTI caused by ESBL-producing E. coli.

Materials and methods

This prospective cohort study was conducted between January 2012 and March 2014 in cases of community-onset UTI caused by E. coli. Patients with UTI due to ESBL-producing E. coli and patients with UTI due to non-ESBL-producing E. coliwere compared to identify risk factors for ESBL-producing E. coli in the community.

Results

A total of 305 patients (116 males [46.4%]; mean age: 57.76 ± 18.06 years) were included in the study. Among these patients, 154 (50.5%) were infected with ESBL-producing E. coli. In multivariate analysis, the healthcare-associated UTI (odds ratio [OR]: 1.80; 95% confidence interval [CI]: 1.02–3.18; P = 0.041), upper urinary tract infection (OR: 3.05; 95% CI: 1.76–5.29; P < 0.0001), use of antibiotics in the preceding 6 months (OR: 2.28; 95% CI: 1.21–4.30; P = 0.011), and having two or more risk factors (OR: 4.03; 95% CI: 1.73–9.35; P = 0.001) were the significant factors associated with increased risk of community-onset UTIs due to ESBL-producing E. coli.

Conclusion

The increasing prevalence ofESBL-producing E. coli makes it difficult to decide the empirical therapy in UTIs, especially in patients with two or more of the risk factors. A better understanding of the epidemiology and risk factors associated with community-onset UTIs due to ESBL-producing E. coli may have significant implications in decision-making for empirical antimicrobial treatment.

Virulence-associated traits and in vitro biofilm-forming ability of Escherichia coli isolated from a major river traversing Northern India

Several strains of Escherichia coli harbor virulence traits, resulting in E. coli-related intestinal and extra-intestinal infections. Various studies have reported that extra-intestinal pathogenic E. coli (ExPEC) strains were prevalent in nonhuman reservoirs, including environmental waterways. It is therefore important to identify the pathogenic potential and/or ExPEC status of E. coli strains inhabiting the aquatic environments associated with anthropogenic activities. Besides virulence-associated genes, biofilm production also helps in the survival of E. coli in environmental waterbodies. Thus, the aim of the current study was to assess the virulence potential, ExPEC status, and biofilm-producing capability of E. coli isolated from the River Yamuna, a major river traversing the National Capital Region of Delhi, India. We also tried to discern a co-relation, if any, between virulence, biofilm formation, and antimicrobial resistance in these strains. Our results indicated that virulence-associated genes were scarce and none of the strain qualified the molecular criteria essential for ExPEC. This suggested that E. coli strains which can presumably cause human extra-intestinal infections were not prominent in the River Yamuna. However, the fact that more than 80% of the aquatic E. coli isolates were moderate and strong biofilm producers suggests that E. coli in these environments might serve as opportunistic pathogens. Also, no unequivocal association was observed between biofilm production, virulence, and β-lactamase genes in E. coli strains. As per the best of our knowledge, this is the first study where the relationship between virulence, biofilms, and antimicrobials has been examined in E. coli, isolated from an Indian urban aquatic waterbody.

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.

Risk factors for community-onset bloodstream infection with extended-spectrum β-lactamase-producing Enterobacteriaceae: national population-based case-control study

OBJECTIVES

The aim was to investigate risk factors for community-onset bloodstream infections with extended-spectrum β-lactamase-producing Enterobacteriaceae (EPE BSI).

METHODS

It is mandatory to report EPE BSI to a national register at the Public Health Agency of Sweden. Using this register, we performed a population-based case-control study from 2007 to 2012 of 945 cases and 9390 controls. Exposure data on comorbidity, hospitalization, in- and outpatient antibiotic consumption and socio-economic status were collected from hospital and health registers.

RESULTS

The overall incidence of EPE BSI was 1.7 per 100 000 person-years. The 30-day mortality was 11.3%. Urological disorders inferred the highest EPE BSI risk, adjusted odds ratio (aOR) 4.32 (95% Confidence Interval (CI) 3.41-5.47), followed by immunological disorders, aOR 3.54 (CI 2.01-6.23), haematological malignancy, aOR 2.77 (CI 1.57-4.87), solid tumours, aOR 2.28 (1.76-2.94) and diabetes, aOR 2.03 (1.58-2.61). Consumption of fluoroquinolones or mostly non-EPE-active antibiotics with selective Gram-negative spectrum of activity within the previous 3 months was associated with EPE BSI, aORs 5.52 (CI 2.8-11.0) and 3.8, CI 1.9-7.7) respectively. There was a dose-response relationship in EPE BSI risk with increasing number of consecutive regimens. Antibiotic consumption >3 months before EPE BSI was not associated with increased risk. Higher age, malignancies and education ≤12 years (aORs >2) were associated with increased 30-day mortality.

CONCLUSIONS

Targeted interventions should be directed towards improving care for patients with immunosuppression, urological disorders and subjects with lower socio-economic status. Antibiotic stewardship should focus on reduction of fluoroquinolones.

Current options for the treatment of infections due to extended-spectrum beta-lactamase-producing Enterobacteriaceae in different groups of patients

BACKGROUND

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are a frequent cause of invasive infections worldwide. Carbapenems are nowadays the most used drugs to treat these infections. However, due to the increasing rates of resistance to these antimicrobials, carbapenem-sparing alternatives are being investigated.

OBJECTIVES AND SOURCES

The aim of this narrative literature review is to summarize the published information on the currently available antibiotics for the treatment of ESBL-E infections, providing specific information on three subgroups of patients: Group 1, patients with severe infections or infections from high-risk sources or in severely immunocompromised patients; Group 2, patients with non-severe infections from intermediate-risk source; and Group 3, patients with non-severe urinary tract infection.

CONTENT AND IMPLICATIONS

For patients in Group 1, the current data would support the use of carbapenems. For milder infections, however, particularly urinary tract infections, other non-carbapenem antibiotics can be considered in selected cases, including beta-lactam/beta-lactam inhibitor combinations, cephamycins, temocillin and aminoglycosides. While specific studies should be performed in these situations, individualized decisions may be taken in order to avoid overuse of carbapenems.

A Clinical Prediction Tool for Extended-Spectrum Cephalosporin Resistance in Community-Onset Enterobacterales Urinary Tract Infection

Background

Bacterial resistance to first line antibiotics used to treat community-onset urinary tract infections (UTIs) continues to increase. We sought to create a clinical prediction tool for community-onset UTIs due to extended-spectrum cephalosporin-resistant (ESC-R) Enterobacterales (formerly Enterobacteriaceae, EB).

Methods

A case-control study was performed. The source population included patients presenting to an emergency department (ED) or outpatient practice with an EB UTI between 2010 and 2013. Case patients had ESC-R EB UTIs. Control patients had ESC-susceptible EB UTIs and were matched to cases 1:1 on study year. Multivariable conditional logistic regression was performed to develop the predictive model by maximizing the area under the receiver-operating curve (AUC). Internal validation was performed via bootstrapping.

Results

A total of 302 patients with a community-onset EB UTI were included, with 151 cases and 151 controls. After multivariable analysis, we found that presentation with an ESC-R EB community-onset UTI could be predicted by the following: (1) a history of malignancy; (2) a history of diabetes; (3) recent skilled nursing facility or hospital stay; (4) recent trimethoprim-sulfamethoxazole exposure; and (5) pyelonephritis at the time of presentation (AUC 0.73, Hosmer-Lemeshow goodness-of-fit P value 0.23). With this model, each covariate confers a single point, and a patient with ≥ 2 points is considered high risk for ESC-R EB (sensitivity 80%, specificity 54%). The adjusted AUC after bootstrapping was 0.71.

Conclusions

Community-onset ESC-R EB UTI can be predicted using the proposed scoring system, which can help guide diagnostic and therapeutic interventions.

Phenotypic and Genotypic Characterization of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Asymptomatic Bacteriuria in Pregnancy

Asymptomatic bacteriuria (ASB) has been consistently observed in pregnancy. However, there is a paucity of data on the prevalence and characteristics of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in ASB in pregnant women. Therefore, we sought to investigate ESBL-producing and multidrug-resistant Enterobacteriaceae in antenatal women with ASB. Urine samples were collected from 310 asymptomatic pregnant women attending primary antenatal clinics and screened for significant bacteriuria. Isolates of Enterobacteriaceae were phenotypically tested for their ESBL production. ESBL genes (CTX-M, TEM, and SHV genes) were then amplified by polymerase chain reaction (PCR). Multiplex PCRs were used to perform phylogenetic typing of ESBL-producing Escherichia coli isolates and to examine the commonality of sequence type 131 (ST131)-O25b and ST131-O16. A total of 103 (33.2%) pregnant women were positive for significant bacteriuria (80 Enterobacteriaceae). Of these isolates, 32.5% (n = 26) were ESBL producers and had a higher rate of multidrug resistance than non-ESBL producers. Genotypic characterization of ESBL-producing isolates showed that 84.6% had the bla_CTX-M gene (bla_CTX-M-15 = 77.3%; bla_CTX-M-9 = 18.2%). None of the isolates were of the TEM or SHV type. Half of the ESBL-producing E. coli isolates were of the phylogroup B2, and 4 (20%) isolates were of the ST131-O16 clonal subgroup. This study is the first in Egypt to provide evidence for the high prevalence of ESBL-producing Enterobacteriaceae in pregnant women with ASB. It also represents an important step toward genotypic characterization of this resistant form of bacteria, which may be useful for future antimicrobial studies.

Isolation of Extended-Spectrum β-lactamase- (ESBL-) Producing Escherichia coli and Klebsiella pneumoniae from Patients with Community-Onset Urinary Tract Infections in Jimma University Specialized Hospital, Southwest Ethiopia

Background

Klebsiella pneumoniae and Escherichia coli are the major extended-spectrum β-lactamase- (ESBL-) producing organisms increasingly isolated as causes of complicated urinary tract infections and remain an important cause of failure of therapy with cephalosporins and have serious infection control consequence.

Objective

To assess the prevalence and antibiotics resistance patterns of ESBL-producing Escherichia coli and Klebsiella pneumoniae from community-onset urinary tract infections in Jimma University Specialized hospital, Southwest Ethiopia, 2016.

Methodology

A hospital-based cross-sectional study was conducted, and a total of 342 urine samples were cultured on MacConkey agar for the detection of etiologic agents. Double-disk synergy (DDS) methods were used for detection of ESBL-producing strains. A disc of amoxicillin + clavulanic acid (20/10 µg) was placed in the center of the Mueller–Hinton agar plate, and cefotaxime (30 µg) and ceftazidime (30 µg) were placed at a distance of 20 mm (center to center) from the amoxicillin + clavulanic acid disc. Enhanced inhibition zone of any of the cephalosporin discs on the side facing amoxicillin + clavulanic acid was considered as ESBL producer.

Results

In the current study, ESBL-producing phenotypes were detected in 23% (n = 17) of urinary isolates, of which Escherichia coli accounts for 76.5% (n = 13) and K. pneumoniae for 23.5% (n = 4). ESBL-producing phenotypes showed high resistance to cefotaxime (100%), ceftriaxone (100%), and ceftazidime (70.6%), while both ESBL-producing and non-ESBL-producing isolates showed low resistance to amikacin (9.5%), and no resistance was seen with imipenem. In the risk factors analysis, previous antibiotic use more than two cycles in the previous year (odds ratio (OR), 6.238; 95% confidence interval (CI), 1.257–30.957; p = 0.025) and recurrent UTI more than two cycles in the last 6 months or more than three cycles in the last year (OR, 7.356; 95% CI, 1.429–37.867; p = 0.017) were found to be significantly associated with the ESBL-producing groups.

Conclusion

Extended-spectrum β-lactamases- (ESBL-)producing strain was detected in urinary tract isolates. The occurrence of multidrug resistance to the third-generation cephalosporins, aminoglycosides, fluoroquinolones, trimethoprim-sulfamethoxazole, and tetracyclines is more common among ESBL producers. Thus, detecting and reporting of ESBL-producing organisms have paramount importance in the clinical decision-making.

Incidence of multidrug resistance and extended-spectrum beta-lactamase expression in community-acquired urinary tract infection among different age groups of patients

OBJECTIVES

Urinary tract infection (UTI) is a frequent disorder and depends on age and gender. Ineffective empiric treatment of UTI is common when associated with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae. The aim of the study was to investigate the prevalence of Gram-negative uropathogens of E. coli and K. pneumoniae in different age groups along with the identification of ESBL-producing uropathogens and antimicrobial susceptibility profiles.

MATERIALS AND METHODS

A total of 247 uropathogens of E. coli and K. pneumoniae were collected over a period of 1 year (January-December 2015) from various diagnostic centers of Karachi city (Pakistan). Antimicrobial susceptibility analysis was performed by disc diffusion method, and identification of ESBL was performed by double disc synergy test. Categorical data of ESBL and non-ESBL uropathogens were analyzed by Pearson's Chi-square test.

RESULTS

The study of 247 patients with community-acquired UTI comprised 72% females and 28% males, illustrating an increased prevalence of UTIs among females. It was also revealed that 90% belonged to the age group of 16-30 years whereas 78% related to the age group of 46-60 years. ESBL was found positive in 33.5% (63/188) of E. coli and 15.25% (9/59) in K. pneumonia, with a significant association i.e., (p =0.007). Amikacin, fosfomycin, imipenem, and tazobactam/piperacillin were found to be the effective treatment options. A significant association was found between ESBL-producing uropathogens against ciprofloxacin, enoxacin, and amoxicillin/clavulanic acid resistance (P < 0.05).

CONCLUSIONS

It was concluded that for effective treatment of UTIs, appropriate screening of ESBL and culture sensitivity must be employed instead of empiric treatment.

Outpatient Antibiotic Consumption for Urinary Infections in Croatia 2005 - 2014: What can be Learned from Utilization Trends

AIM

The aim of this study was to determine quantities of antibiotics used mainly or exclusively for urinary tract infections in Croatia between 2005 and 2014, to describe utilisation trends, and general consequences of antibiotic consumption on antimicrobial resistance.

METHODS

Antibiotic utilisation data were obtained from annual reports of both the Croatian Drug Agency and Croatian Academy of Medical Sciences. Antibiotic consumption was expressed in DDD/1000 inhabitants/day (DDD TID). Antimicrobial resistance was analysed for E. coli, E. faecalis, E. faecium, P. aeruginosa, Klebsiella spp., P. mirabilis. Descriptive statistics were used to process data and calculate trends.

RESULTS

Overall, utilisation of antibacterials decreased by 4.8% (from 3,35 to 3,19 DDD TID), while trends of individual agents varied substantially - from 87% decline for ceftibuten to 160% rise for levofloxacin. The consumption of quinolones increased by 32.3%. This was mostly due to increased ciprofloxacin consumption (144% raise). Sulfamethoxazole-trimethoprim declined by 57%, while nitrofurantoin increased by 86%. The use of fosfomycin was marginal. Antimicrobial resistance of E. coli increased against quinolones by 54.5%, and against nitrofurantoin by 2-3%. Quinolone resistance of other pathogens (Klebiella spp, Proteus mirabilis), increased variably - between 17.2% (Klebsiella) and 90% (Proteus), while for P. aeruginosa remained the same at 22%.

CONCLUSION

High rates of antimicrobial utilisation require prescribing restrictions and educational interventions. The increased use of fluoroquinolones is a potentially serious public health threat due to the rapid development of resistance among uropathogens. This threat can be avoided by greater use of nitrofurantoin and fosfomycin.