Synergistic Antibacterial Activity of Gallic Acid Based Chalcone Indl 2 by Inhibiting Efflux Pump Transporters

As a part of novel discovery of drugs from natural resources, present study was undertaken to explore the antibacterial potential of chalcone Indl-2 in combination with different group of antibiotics. MIC of antibiotics was reduced up to eight folds against the different cultures of E. coli by both chalcones. Among the two compounds, the i. e. 1-(3', 4,'5'-trimethoxyphenyl)-3-(3-Indyl)-prop-2-enone (6, Indl-2), a chalcone derivative of gallic acid (Indl-2) was better along with tetracycline (TET) worked synergistically and was found to inhibit efflux transporters as obvious by ethidium bromide efflux confirmed by ATPase assays and docking studies. In combination, Indl-2 kills the MDREC-KG4 cells, post-antibiotic effect (PAE) of TET was prolonged and mutant prevention concentration (MPC) of TET was also decreased. In-vivo studies revealed that Indl-2 reduces the concentration of TNF-α. In acute oral toxicity study, Indl-2 was non-toxic and well tolerated up-to dose of 2000 mg/kg. Perhaps, the study is going to report gallic acid derived chalcone as synergistic agent acting via inhibiting the primary efflux pumps.

Preclinical characterization and in silico safety assessment of three virulent bacteriophages targeting carbapenem-resistant uropathogenic Escherichia coli

Phage therapy has recently been revitalized in the West with many successful applications against multi-drug-resistant bacterial infections. However, the lack of geographically diverse bacteriophage (phage) genomes has constrained our understanding of phage diversity and its genetics underpinning host specificity, lytic capability, and phage-bacteria co-evolution. This study aims to locally isolate virulent phages against uropathogenic Escherichia coli (E. coli) and study its phenotypic and genomic features. Three obligately virulent Escherichia phages (øEc_Makalu_001, øEc_Makalu_002, and øEc_Makalu_003) that could infect uropathogenic E. coli were isolated and characterized. All three phages belonged to Krischvirus genus. One-step growth curve showed that the latent period of the phages ranged from 15 to 20 min, the outbreak period ~ 50 min, and the burst size ranged between 74 and 127 PFU/bacterium. Moreover, the phages could tolerate a pH range of 6 to 9 and a temperature range of 25-37 °C for up to 180 min without significant loss of phage viability. All phages showed a broad host spectrum and could lyse up to 30% of the 35 tested E. coli isolates. Genomes of all phages were approximately ~ 163 kb with a gene density of 1.73 gene/kbp and an average gene length of ~ 951 bp. The coding density in all phages was approximately 95%. Putative lysin, holin, endolysin, and spanin genes were found in the genomes of all three phages. All phages were strictly virulent with functional lysis modules and lacked any known virulence or toxin genes and antimicrobial resistance genes. Pre-clinical experimental and genomic analysis suggest these phages may be suitable candidates for therapeutic applications.

Epidemiology of Cefotaxime-Hydrolysing β-Lactamase-Producing Escherichia coli in Children with Diarrhoea Reported Globally between 2012 and 2022

The global spread of cefotaxime-hydrolysing β-lactamase (CTX-M)-producing Escherichia coli (E. coli) and its associated impact on paediatric diarrhoeal treatment and management has become a public health concern. This review assessed surveillance studies on CTX-M-producing E. coli associated with diarrhoea in children published between 2012 and 2022 globally. A total of thirty-eight studies were included for data analysis, categorised into continental regions, and tabulated. The majority (68%) of studies were conducted in Asian countries while few studies were conducted in Europe (11%) and Africa (18%), respectively. On the African continent, the majority (11%) of studies were conducted in Northern Africa while no studies were reported in East Africa. On the American continent, 3% of the studies were reported from South America. The studies included were classified into diarrheagenic E. coli (74%; 28/38) and faecal carriage (26%; 10/38). Of all the E. coli pathotypes associated with CTX-M production, EPEC was frequently reported. The prevalence of CTX-M-producing E. coli including the CTX-M-15-producing variants ranged between 1% and 94%. About 37% of the studies generalised the report as blaCTX-M-positive E. coli. The use of sequencing in characterising the CTX-M-producing E. coli was reported in only 32% of all the studies. This review provides information on the epidemiology of CTX-M-15-producing E. coli in paediatric diarrhoea and the extent to which surveillance is being performed. This is relevant in informing clinical practice for the management of diarrhoea as well as the design of future surveillance studies.

Nationwide surveillance in Thailand revealed genotype-dependent dissemination of carbapenem-resistant Enterobacterales

Carbapenem-resistant Enterobacterales (CRE) are a serious public health threat because of their rapid dissemination. To determine the epidemiological and genetic characteristics of CRE infections in Thailand, we performed whole-genome sequencing of 577 carbapenem-resistant Klebsiella pneumoniae isolates and 170 carbapenem-resistant Escherichia coli isolates from hospitals across the nation. The four most prevalent carbapenemase genes harboured by these bacteria were bla NDM-1, bla NDM-5, bla OXA-181 and bla OXA-232. The gene bla NDM-1 was identified in diverse sequence types. The gene bla NDM-5 was identified almost exclusively in E. coli . The genes bla OXA-181, bla OXA-232, and co-carriage of bla NDM-1 and bla OXA-232 were found in specific sequence types from certain provinces. Replicon typing revealed the diverse backbones of bla NDM-1- and bla NDM-5-harbouring plasmids and successful expansion of bla NDM-1-harbouring IncN2-type plasmids. Core-genome single-nucleotide polymorphism analysis suggested that bla OXA-181-, bla OXA-232-, bla NDM-5-, and co-carriage of bla NDM-1 and bla OXA-232-associated sub-clonal lineages have recently predominated in the provinces from where these isolates were isolated. Thus, we demonstrate genotype-dependent dissemination of CRE in Thailand, which is helpful for establishing infection-control strategies in CRE-endemic areas.

Characterization and genome analysis of a broad lytic spectrum bacteriophage P479 against multidrug-resistant Escherichia coli

The increase of multi-drug resistant and multi-serotypes of pathogenic Escherichia coli has brought more severe challenge to control infection. Nowadays, bacteriophage is a promising tool to treat colibacillosis as an alternative of antibiotics. A coliphage P479, isolated from sewage of poultry farm, could lyse multiple serotypes, including not only O1, O2, O8, O9, O21, O78, O83, O145 of Avian pathogenic E. coli, but O157:H7 of Enterohaemorrhagic E. coli and O18:K1:H7 Neonatal meningitis E. coli. Additionally, P479 could also lyse multi-drug resistant E. coli. These indicated that P479 had good lytic ability. One-step growth curve revealed that the latent time period of P479 was 10 min and the burst size was about 318 PFU/cell. Stability tests demonstrated that P479 had good stability under various temperature (4 to 50 °C) and pH (3 to11) conditions. P479 contained of a linear, double-stranded DNA molecule of 172,033 bp with 40.3% GC content. P479 contained 296 putative coding sequences (CDSs) and two tRNA genes. Based on genomic comparison, P479 was classified as a member of genus Gaprivervirus, subfamily Tevenvirinae, family Myoviridae, order Caudovirales. No known virulent or lysogenic genes were detected in the genome of P479, manifesting P479 was safe to adhibit. Antibacterial activity in vitro manifested that P479 has varying degrees bacteriostatic activity against different bacteria. According to the above properties, P479 has the potential to be applied in phage therapy in the future.

Polyclonal spread of blaCTX-M-15 through high-risk clones of Escherichia coli at a tertiary hospital in Ethiopia

OBJECTIVE

The burden of antimicrobial resistance and spread of epidemic clones are rarely reported from low-income countries. We aimed to investigate genome-based epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) at a tertiary hospital in Jimma, Ethiopia.

METHODS

Bacteria were isolated from clinical specimens obtained from Jimma Medical Center and subjected to species identification (MALDI-TOF), antibiotic susceptibility testing (disk diffusion), and whole genome sequencing (Illumina HiSeq2500). Genomic data analysis was performed using the Enterobase and Center for Genomic Epidemiology bioinformatics pipelines. A maximum likelihood tree was generated using FastTree/2.1.8 based on SNPs in shared genomic regions to identify transmission clusters.

RESULT

E. coli isolates (n=261) were collected from 1,087 single non-repeat clinical specimens over a period of five months in 2016. The prevalence of ESBL-EC was (54.7%, 143/261), and 96% of these isolates were resistant to multiple classes of antibiotics. ESBL-gene bla_CTX-M-15 was present in 88.4.% of the isolates (122/138). Genes conferring resistance to aminoglycosides and ciprofloxacin - aac(6')-Ib-cr (62.3%, 86/138), phenicols - catB3 (56.5%, 78/138), sulfonamides - sul1 (68.1%, 94/138), trimethoprim - dfrA17 (57.9%, 80/138) and macrolides - mph(A) (67.3%, 93/138) were detected. The most prevalent sequence types were ST410 (23%), ST648 (17%), ST131 (10%), and ST167 (7%). Isolates of same sequence type collected from different units of the hospital were highly similar in SNP-analysis.

CONCLUSION

A high prevalence of ESBL, and dissemination of bla_CTX-M-15 through multiple high-risk clones of E. coli, was detected. The nosocomial spread of multidrug-resistant ESBL-EC within the hospital puts vulnerable patients at risk for difficult-to-treat infections.

Isolation, characterization, and genomic analysis of the novel T4-like bacteriophage ΦCJ20

Pathogenic Escherichia coli infections have been consistently reported annually. The basic characteristics and genome of the newly isolated ΦCJ20 from swine feces was analyzed. To determine basic characteristics, dotting assays and double-layer agar assays were conducted. Bacteriophage particles were analyzed via transmission electron microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed to determine the sizes of major structural proteins. The complete genome of the phage was analyzed. Bacteriophage particles were identified as Myoviridae, with a head measuring 110.57 ± 1.89 nm and a contractile tail measuring 107.97 ± 3.20 nm and were found to infect E. coli. Major structural proteins of ΦCJ20 showed two well-pronounced bands of approximately 53.6 and 70.9 kDa. The genome size of ΦCJ20 was 169,884 bp, and 118 of 307 open reading frames were annotated. This study provides a baseline for the development of E. coli infection treatment strategies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-021-00906-y.

Epidemiology of extended-spectrum β-lactamase and metallo-β-lactamase-producing Escherichia coli in South Asia

Aim: To determine the prevalence of extended-spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL)-producing Escherichia coli in South Asia. Methodology: A systematic review and meta-analysis of data published in PubMed, EMBASE, Web of Science and Scopus. Results: The pooled prevalence of ESBL and MBL-producing E. coli in South Asia were 33% (95% CI: 27-40%) and 17% (95% CI: 12-24%), respectively. The prevalence of bla_CTX-M type was 58% (95% CI: 49-66%) with bla_CTX-M-15 being the most prevalent (51%, 95% CI: 40-62%) variant. The most prevalent MBL variant was bla_NDM-1 (33%, 95% CI: 20-50%). Conclusion: This study suggests a high prevalence of ESBLs and MBLs among E. coli clinical isolates. Comprehensive resistance surveillance is required to guide clinicians prescribing antibiotics in South Asia.

Epidemiology and prevalence of extended-spectrum β-lactamase- and carbapenemase-producing Enterobacteriaceae in humans, animals and the environment in West and Central Africa

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) are widespread. Here we used the 'One Health' approach to determine knowledge gaps on ESBL-E and CPE in West and Central Africa. We searched all articles on ESBL-E and CPE in these African regions published in PubMed, African Journals Online and Google Scholar from 2000 onwards. Among the 1201 articles retrieved, we selected 165 studies (West Africa, 118; Central Africa, 47) with data from 22 of the 26 West and Central Africa countries. Regarding the settings, 136 articles focused only on humans (carriage and/or infection), 6 articles on humans and animals, 13 on animals, 1 on humans and the environment, 8 on the environment and 1 on humans, animals and environments. ESBL-E prevalence ranged from 11-72% in humans and 7-79% in aquatic environments (wastewater). In animals, ESBL-E prevalence hugely varied: 0% in cattle, 11-36% in chickens, 20% in rats, 21-71% in pigs and 32-75% in dogs. The bla_CTX-M-15 gene was the predominant ESBL-encoding gene and was associated with plasmids of incompatibility groups F, H, K, Y, N, I1 and R. CPE were studied only in humans. Class B metallo-β-lactamases (NDM) and class D oxacillinases (OXA-48 and OXA-181) were the most common carbapenemases. Our results show major knowledge gaps, particularly on ESBL and CPE in animals and the environment, that might limit antimicrobial resistance management in these regions. The results also emphasise the urgent need to improve active surveillance programmes in each country and to support antimicrobial stewardship.

Antibiotic Resistance Profile and Diversity of Subtypes Genes in Escherichia coli Causing Bloodstream Infection in Northern Vietnam

BACKGROUND:

Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). But there are still limited studies in Northern Vietnam.

AIM:

The aim of the study was to determine the antibiotic resistance profile and characteristics of subtypes genes in Escherichia coli causing BSIs in Northern Vietnam.

METHODS:

The cross-sectional study was done in the period from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests were performed at the lab of the hospital.

RESULTS:

In 56 E. coli strains isolating 39.29 % produced ESBL. 100% of the isolates harbored blaTEM gene, but none of them had the blaPER gene. The prevalence of ESBL producers and ESBL non-producers in blaCTX-M gene was 81.82%, and 73.53%, in blaSHV gene was 18.18% and 35.29%. Sequencing results showed three blaTEM subtypes (blaTEM 1, 79, 82), four blaCTX-M subtypes (blaCTX-M-15, 73, 98, 161), and eight blaSHV subtypes (blaSHV 5, 7, 12, 15, 24, 33, 57, 77). Antibiotic resistance was higher in ampicillin (85.71%), trimethoprim/sulfamethoxazole (64.29%) and cephazolin (50%). Antibiotics were still highly susceptible including doripenem (96.43%), ertapenem (94.64%), amikacin (96.43%), and cefepime (89.29%).

CONCLUSION:

In Escherichia coli causing BSIs, antibiotic resistance was higher in ampicillin, trimethoprim/sulfamethoxazole and cephazolin. Antibiotics was highly susceptible including doripenem, ertapenem, amikacin, and cefepime.

Antimicrobial resistance in Clostridium difficile ribotype 017

Introduction: Antimicrobial resistance (AMR) played an important role in the initial outbreaks of Clostridium difficile infection (CDI) in the 1970s. C. difficile ribotype (RT) 017 has emerged as the major strain of C. difficile in Asia, where antimicrobial use is poorly regulated. This strain has also caused CDI outbreaks around the world for almost 30 years. Many of these outbreaks were associated with clindamycin and fluoroquinolone resistance. AMR and selective pressure is likely to be responsible for the success of this RT and may drive future outbreaks.Areas covered: This narrative review summarizes the prevalence and mechanisms of AMR in C. difficile RT 017 and transmission of these AMR mechanisms. To address these topics, reports of outbreaks due to C. difficile RT 017, epidemiologic studies with antimicrobial susceptibility results, studies on resistance mechanisms found in C. difficile and related publications available through Pubmed until September 2019 were collated and the findings discussed.Expert opinion: Primary prevention is the key to control CDI. This should be achieved by developing antimicrobial stewardship in medical, veterinary and agricultural practices. AMR is the key factor that drives CDI outbreaks, and methods for the early detection of AMR can facilitate the control of outbreaks.

Fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae in hospital and community settings in Chad

Background

Fecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) remains poorly documented in Africa. The objective of this study was to determine the prevalence of ESBL-PE fecal carriage in Chad.

Methods

In total, 200 fresh stool samples were collected from 100 healthy community volunteers and 100 hospitalized patients from January to March 2017. After screening using ESBL-selective agar plates and species identification by MALDI-TOF mass spectrometry, antibiotic susceptibility was tested using the disk diffusion method, and ESBL production confirmed with the double-disc synergy test. The different ESBL genes in potential ESBL-producing isolates were detected by PCR and double stranded DNA sequencing. Escherichia coli phylogenetic groups were determined using a PCR-based method.

Results

ESBL-PE fecal carriage prevalence was 44.5% (51% among hospitalized patients vs 38% among healthy volunteers; p < 0.05). ESBL-producing isolates were mostly Escherichia coli (64/89) and Klebsiella pneumoniae (16/89). PCR and sequencing showed that 98.8% (87/89) of ESBL-PE harbored bla_CTX-M genes: bla_CTX-M-15 in 94.25% (82/87) and bla_CTX-M-₁₄ in 5.75% (5/87). Phylogroup determination by quadruplex PCR indicated that ESBL-producing E. coli isolates belonged to group A (n = 17; 27%), C (n = 17; 27%), B2 (n = 9; 14%), B1 (n = 8; 13%), D (n = 8; 13%), E (n = 1; 1.6%), and F (n = 1; 1.6%). The ST131 clone was identified in 100% (9/9) of E. coli B2 strains.

Conclusions

The high fecal carriage rate of ESBL-PE associated with CTX-M-15 in hospital and community settings of Chad highlights the risk for resistance transmission between non-pathogenic and pathogenic bacteria.

Comparative Drug Resistance Reversal Potential of Natural Glycosides: Potential of Synergy Niaziridin & Niazirin

Background:

Due to the limited availability of antibiotics, Gram-negative bacteria (GNB) acquire different levels of drug resistance. It raised an urgent need to identify such agents, which can reverse the phenomenon of drug resistance.

Objective:

To understand the mechanism of drug resistance reversal of glycosides; niaziridin and niazirin isolated from the pods of Moringa oleifera and ouabain (control) against the clinical isolates of multidrug-resistant Escherichia coli.

Methods:

The MICs were determined following the CLSI guidelines for broth micro-dilution. In-vitro combination studies were performed by broth checkerboard method followed by Time-Kill studies, the efflux pump inhibition assay, ATPase inhibitory activity, mutation prevention concentration and in-silico studies.

Results:

The results showed that both glycosides did not possess antibacterial activity of their own, but in combination, they reduced the MIC of tetracycline up to 16 folds. Both were found to inhibit efflux pumps, but niaziridin was the best. In real time expression pattern analysis, niaziridin was also found responsible for the down expression of the two important efflux pump acrB & yojI genes alone as well as in combination. Niaziridin was also able to over express the porin forming genes (ompA & ompX). These glycosides decreased the mutation prevention concentration of tetracycline.

Conclusion:

This is the first ever report on glycosides, niazirin and niaziridin acting as drug resistance reversal agent through efflux pump inhibition and modulation of expression pattern drug resistant genes. This study may be helpful in preparing an effective antibacterial combination against the drug-resistant GNB from a widely growing Moringa oleifera.

Effective Oral Combination Treatment for Extended-Spectrum Beta-Lactamase-Producing Escherichia coli

Background: Extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) is increasing worldwide. The drugs of choice for treatment of ESBLs are parenteral carbapenems. The aim of this study was to evaluate the in vitro and in vivo efficacy of a new combination of oral cephalosporins and amoxicillin/clavulanate in treatment of ESBL-EC. Methods: A total of 150 ESBL-EC samples were collected over 1 year from two referral centers. Synergistic studies of cephalosporins and amoxicillin/clavulanate were performed in vitro using disk approximation and disk replacement methods. Combination treatment was assessed in vivo on 20 ESBL-EC urinary tract infection (UTI) patients. Results: ESBL-EC isolates were confirmed in 150 patients with a mean age of 46.67 years, 75.2% of them being women. Antibiotic susceptibility testing of isolates indicated high resistance rate to oral antibiotics. The frequency of positive synergy and mean distance of synergy between cephalosporins and amoxicillin/clavulanate was significantly higher with cefotaxime and cefixime compared with cefpodoxime, cefdinir, and ceftazidime using disk approximation and disk replacement methods (p < 0.05). Addition of amoxicillin/clavulanate enhanced the susceptibility rate with cefixime from 8.6% to 86.3%, significantly higher than with other cephalosporins (p < 0.0005). Cefixime and amoxicillin/clavulanate synergy was not affected by age, gender, hospital, department, sample type, or bacterial load. Eighteen of 20 ESBL-EC-positive UTI patients had a positive in vitro synergy test and complete clinical and microbiological resolution after completion of cefixime and amoxicillin/clavulanate oral treatment course. Conclusions: Cefixime and amoxicillin/clavulanate combination therapy could be an effective oral outpatient treatment option for ESBL-EC. In vitro synergistic testing is simple and predictive of successful treatment.

Microcin PDI Inhibits Antibiotic-Resistant Strains of Escherichia coli and Shigella through a Mechanism of Membrane Disruption and Protection by Homotrimer Self-Immunity

Microcin PDI (MccPDI), a class IIa microcin that is produced by Escherichia coli strains 25 and 284, is known to inhibit foodborne pathogenic enterohemorrhagic E. coli serotypes O157:H7 and O26. Here we demonstrate that MccPDI can inhibit Shigella strains and E. coli isolates that are multidrug resistant, the latter including strains known to cause urinary tract infections in people and companion animals. Two exceptions out of 17 strains were identified. One of the two resistant E. coli isolates (AR0349) has a mutation in a critical amino acid residue that was identified in previous work as a requisite for the MccPDI precursor protein (McpM) to interact with outer membrane porin F (OmpF) on susceptible cells. The second resistant E. coli strain (MAD 96) had no mutations in ompF, but it was PCR positive for two antimicrobial peptides, of which colicin Ia/Ib likely inhibits the MccPDI-producing strain during coculture. Recombinant McpM was still effective against strain MAD 96. In an assessment of how MccPDI affects susceptible strains, results from both an extracellular ATP assay and a nucleic acid staining assay were consistent with membrane damage, while the addition of 200- to 600-Da polyethylene glycol (PEG) to cocultures protected against MccPDI (>600-Da PEG did not provide protection). Further studies using a paraformaldehyde cross-linking experiment and a bacterial two-hybrid assay demonstrated that MccPDI immunity protein (McpI) forms a multimeric complex with itself and presumably protects the producer strain from within the periplasm through an unknown mechanism.IMPORTANCE Microcins represent potential alternatives to conventional antibiotics for human and veterinary medicine. For them to be applied in this manner, however, we need to better understand their spectrum of activity, how these proteins interact with susceptible cells, and how producer cells are protected against the antimicrobial properties of the microcins. For microcin PDI (MccPDI), we report that the spectrum of activity likely includes most E. coli strains due to a conserved binding motif found on an outer membrane protein. Shigella has this motif as well and is susceptible to MccPDI killing via damage to the bacterial membrane. Receptor specificity suggests that these proteins could be used without causing large-scale disruptions to a microbiota, but this also increases the likelihood that resistance can evolve via random mutations. As with conventional antibiotics, good stewardship will be needed to preserve the efficacy of microcins should they be deployed for clinical use.

Prevalence of and risk factor for community-onset third-generation cephalosporin-resistant Escherichia coli bacteremia at a medical center in Taiwan

Background

Increased resistance to third-generation cephalosporin (3GC) is a serious concern for community-onset Escherichia coli infection because this resistance easily delays effective treatment. This study surveyed the current antimicrobial resistance pattern among E. coli isolates that cause community-onset bacteremia, with a special focus on the prevalence of and the risk factors for 3GC resistance, and determined factors for poor outcomes among patients with community-onset E. coli bacteremia.

Methods

This retrospective study was conducted at a tertiary-care teaching hospital in Taiwan. All adult patients with community-onset E. coli bacteremia between January 1, 2015, and December 31, 2015 were enrolled and were divided into two groups depending on whether the E. coli isolate was susceptible to 3GCs. Risk factors for 3GC resistance, 14-day all-cause mortality, and length of hospital stay were analyzed.

Results

The overall rate of 3GC resistance among E. coli isolates causing community-onset bacteremia was 19.7%, whereas it was 9.6% if only isolates causing community-acquired bacteremia were considered. Independent risk factors for 3GC-resistant community-onset E. coli bacteremia were hospitalization within the past 1 year (odds ratio: 2.4, 95% confidence interval: 1.6–3.7, P < 0.001), exposure to antibiotics within the past 15 days (2.6, 1.4–4.9, P = 0.002), residence in nursing home or long-term care facility (3.6, 1.0–12.3, P = 0.044), presence of underlying genitourinary disease (1.9, 1.2–2.9, P = 0.005), and presence of indwelling implantable intravenous port (2.2, 1.1–4.1, P = 0.021). 3GC resistance was independently associated with increased length of hospital stays (P < 0.001).

Conclusion

In this study, the prevalence of 3GC resistance was high among both patients with community-onset and those with community-acquired E. coli bacteremia. 3GC resistance is a strong independent risk factor for length of hospital stay. The effectiveness of empirical antibiotic treatment would partially explain the impact of 3GC resistance, but more evidence is needed. The choice of appropriate empirical antibiotics for community-onset E. coli bacteremia might impact outcomes in terms of the length of hospital stay and need to be individualized according to the patient-specific risk for acquiring drug-resistant pathogens.

Extended-spectrum β-lactamase prevalence and virulence factor characterization of enterotoxigenic Escherichia coli responsible for acute diarrhea in Nepal from 2001 to 2016

Background

Multidrug-resistant (MDR) Gram-negative bacterial species are an increasingly dangerous public health threat, and are now endemic in many areas of South Asia. However, there are a lack of comprehensive data from many countries in this region determining historic and current MDR prevalence. Enterotoxigenic Escherichia coli (ETEC) is a leading cause of both acute infant diarrhea and traveler’s diarrhea in Nepal. The MDR prevalence and associated resistance mechanisms of ETEC isolates responsible for enteric infections in Nepal are largely unknown.

Methods

A total of 265 ETEC isolates were obtained from acute diarrheal samples (263/265) or patient control samples (2/265) at traveler’s clinics or regional hospitals in Nepal from 2001 to 2016. Isolates were screened for antibiotic resistance, to include extended spectrum beta-lactamase (ESBL) production, via the Microscan Automated Microbiology System. ETEC virulence factors, specifically enterotoxins and colonization factors (CFs), were detected using multiplex PCR, and prevalence in the total isolate population was compared to ESBL-positive isolates. ESBL-positive isolates were assessed using multiplex PCR for genetic markers potentially responsible for observed resistance.

Results

A total of 118/265 (44.5%) ETEC isolates demonstrated resistance to ≥2 antibiotics. ESBL-positive phenotypes were detected in 40/265 isolates, with isolates from 2008, 2013, 2014, and 2016 demonstrating ESBL prevalence rates of 1.5, 34.5, 31.2, and 35.0% respectively. No difference was observed in overall enterotoxin characterization between the total ETEC and ESBL-positive populations. The CFs CS2 (13.6%), CS3 (25.3%), CS6 (30.2%), and CS21 (62.6%) were the most prevalent in the total ETEC population. The ESBL-positive ETEC isolates exhibited a higher association trend with the CFs CS2 (37.5%), CS3 (35%), CS6 (42.5%), and CS21 (67.5%). The primary ESBL gene identified was bla_CTX-M-15 (80%), followed by bla_SHV-12 (20%) and bla_CTX-M-14 (2.5%). The beta-lactamase genes bla_TEM-1 (40%) and bla_CMY-2 (2.5%) were also identified. It was determined that 42.5% of the ESBL-positive isolates carried multiple resistance genes.

Conclusion

Over 30% of ETEC isolates collected post-2013 and evaluated in this study demonstrated ESBL resistance. Persistent surveillance and characterization of enteric ETEC isolates are vital for tracking the community presence of MDR bacterial species in order to recommend effective treatment strategies and help mitigate the spread of resistant pathogens.

Aspects of urinary tract infections and antimicrobial resistance in hospitalized urology patients in Asia: 10-Year results of the Global Prevalence Study of Infections in Urology (GPIU)

OBJECTIVES

To assess Asian data from Global Prevalence Study on Infections in Urology (GPIU study) which has been performed more than 10 years.

METHODS

Seventeen Asian countries participated in the GPIU study between 2004 and 2013. Data for these countries were collected from the web-based GPIU database. The point prevalence of urinary tract infections (UTI) and antimicrobial susceptibility of representative pathogens were analysed for Asian geographic regions.

RESULTS

A total of 6706 patients (5271 male, 1435 female) were assessed during the study period, and 659 patients were diagnosed with a UTI (9.8%). Of these UTI patients, 436 were male and 223 were female. Mean patient age was 54.9 ± 19.3 years. Pyelonephritis and cystitis were the most common clinical diagnoses, representing 30.7% and 29.9% of patients, respectively. Escherichia coli was the most frequently identified uropathogen (38.7%). For the patients with urinary tract infection, cephalosporins were the most frequently used antibiotics (34.4%), followed by fluoroquinolones (24.1%), aminoglycosides (16.8%). Fluoroquinolone resistance was relatively high (ciprofloxacin 54.9%, levofloxacin 39.0%), and cephalosporin resistance 42% (42.5-49.4%). Of the antibiotics evaluated, uropathogens had maintained the highest level of susceptibility to amikacin and imipenem (24.9% and 11.3% resistance rates, respectively).

CONCLUSION

Uropathogens in many Asian countries had high resistance to broad-spectrum antibiotics. Knowledge of regional and local resistance data and prudent use of antibiotics are important for proper management of UTI in Asian countries.

Universal or targeted approach to prevent the transmission of extended-spectrum beta-lactamase-producing Enterobacteriaceae in intensive care units: a cost-effectiveness analysis

OBJECTIVE

Several control strategies have been used to limit the transmission of multidrug-resistant organisms in hospitals. However, their implementation is expensive and effectiveness of interventions for the control of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) spread is controversial. Here, we aim to assess the cost-effectiveness of hospital-based strategies to prevent ESBL-PE transmission and infections.

DESIGN

Cost-effectiveness analysis based on dynamic, stochastic transmission model over a 1-year time horizon.

PATIENTS AND SETTING

Patients hospitalised in a hypothetical 10-bed intensive care unit (ICU) in a high-income country.

INTERVENTIONS

Base case scenario compared with (1) universal strategies (eg, improvement of hand hygiene (HH) among healthcare workers, antibiotic stewardship), (2) targeted strategies (eg, screening of patient for ESBL-PE at ICU admission and contact precautions or cohorting of carriers) and (3) mixed strategies (eg, targeted approaches combined with antibiotic stewardship).

MAIN OUTCOMES AND MEASURES

Cases of ESBL-PE transmission, infections, cost of intervention, cost of infections, incremental cost per infection avoided.

RESULTS

In the base case scenario, 15 transmissions and five infections due to ESBL-PE occurred per 100 ICU admissions, representing a mean cost of €94 792. All control strategies improved health outcomes and reduced costs associated with ESBL-PE infections. The overall costs (cost of intervention and infections) were the lowest for HH compliance improvement from 55%/60% before/after contact with a patient to 80%/80%.

CONCLUSIONS

Improved compliance with HH was the most cost-saving strategy to prevent the transmission of ESBL-PE. Antibiotic stewardship was not cost-effective. However, adding antibiotic restriction strategy to HH or screening and cohorting strategies slightly improved their effectiveness and may be worthy of consideration by decision-makers.

Antibiotic Resistance in an Indian Rural Community: A 'One-Health' Observational Study on Commensal Coliform from Humans, Animals, and Water

Antibiotic-resistant bacteria are an escalating grim menace to global public health. Our aim is to phenotype and genotype antibiotic-resistant commensal Escherichia coli (E. coli) from humans, animals, and water from the same community with a ‘one-health’ approach. The samples were collected from a village belonging to demographic surveillance site of Ruxmaniben Deepchand (R.D.) Gardi Medical College Ujjain, Central India. Commensal coliforms from stool samples from children aged 1–3 years and their environment (animals, drinking water from children's households, common source- and waste-water) were studied for antibiotic susceptibility and plasmid-encoded resistance genes. E. coli isolates from human (n = 127), animal (n = 21), waste- (n = 12), source- (n = 10), and household drinking water (n = 122) carried 70%, 29%, 41%, 30%, and 30% multi-drug resistance, respectively. Extended spectrum beta-lactamase (ESBL) producers were 57% in human and 23% in environmental isolates. Co-resistance was frequent in penicillin, cephalosporin, and quinolone. Antibiotic-resistance genes bla_CTX-M-9 and qnrS were most frequent. Group D-type isolates with resistance genes were mainly from humans and wastewater. Colistin resistance, or the mcr-1 gene, was not detected. The frequency of resistance, co-resistance, and resistant genes are high and similar in coliforms from humans and their environment. This emphasizes the need to mitigate antibiotic resistance with a ‘one-health’ approach.

A randomized clinical trial on the effectiveness of a symbiotic product to decolonize patients harboring multidrug-resistant Gram-negative bacilli

INTRODUCTION:

We aimed to evaluate the effectiveness of a symbiotic product to decolonize the intestinal tract of patients harboring multidrug-resistant (MDR) Gram-negative bacilli and to prevent nosocomial infections.

METHODS:

This was a randomized, double blind, placebo-controlled clinical trial, conducted in a tertiary-care university hospital. All adult hospitalized patients with a positive clinical culture and a positive rectal swab for any MDR Gram-negative bacilli were potentially eligible. Exclusion criteria were pregnancy, immunosuppression, and bowel obstruction/perforation. The intervention consisted of administering a symbiotic product (Lactobacillus bulgaricus, Lactobacillus rhamnosus, and fructo-oligosaccharides) twice a day for seven days via the oral/enteral route.

RESULTS:

Between August 1, 2012 and December 22, 2013, 116 of 275 eligible patients were allocated to treatment (n=57) and placebo (n=59). Overall, 101 patients received at least four doses of the study products and were included in the modified intention-to-treat analysis. The primary study outcome, a negative rectal swab for MDR Gram-negative bacilli after treatment, was identified in 16.7% (8/48) and 20.7% (11/53) of patients in the experimental and placebo group, respectively (p=0.60). The secondary outcome, the combined incidence of nosocomial respiratory and urinary tract infections, was 37.5% (18/48) in the experimental group versus 22.6% (12/53) in the control group (adjusted odds ratio: 1.95, 95% confidence interval: 0.69-5.50, p=0.21). Length of stay after the beginning of the intervention, incidence of adverse events, and in-hospital mortality rates were similar in both study groups.

CONCLUSIONS:

Under the present study conditions, symbiotic administration was not effective for decolonizing hospitalized patients harboring MDR Gram-negative bacilli.

Clinical importance of the antibiotic regimen in transrectal ultrasound-guided biopsy: quinolone versus cephalosporin

Background

Quinolone is recommended as an antimicrobial prophylaxis to prevent infectious complication after transrectal ultrasound-guided biopsy, but the increased appearance of quinolone-resistant organism has raised concerns about the efficacy of quinolone. The current study was performed to evaluate various clinical factors including antimicrobial regimens associated with infectious complication after transrectal ultrasound-guided prostate biopsy.

Methods

The medical records of 5215 patients who underwent a multicore transrectal ultrasound-guided prostate biopsy between May 2003 and January 2013 at our institution were reviewed. We analyzed clinical variables including prostate-specific antigen, International Prostate Symptom Score, antimicrobial regimen, prostate size, and number of biopsy cores. Univariate and multivariate logistic regression analyses of infection-related hospitalization after prostate biopsy were performed.

Results

The mean age and median prostate-specific antigen of the entire cohort were 66 years and 6.4 ng/ml, respectively. Twenty-eight (0.54 %) patients developed an infectious complication after prostate biopsy that required hospitalization. Patients who received prophylactic quinolone showed a higher infectious hospitalization rate than patients who received prophylactic third-generation cephalosporin (1.5 vs. 0.3 %; p < 0.001). Multivariate logistic regression analysis demonstrated that the International Prostate Symptom Score (odds ratio = 3.18, 95 % confidence interval 1.24–8.13, p = 0.016) and the use of third-generation cephalosporin (odds ratio = 0.21, 95 % confidence interval 0.10–0.44, p < 0.001) were independent predictors of infection-related hospitalization after prostate biopsy.

Conclusion

With the emergence of quinolone-resistant microorganisms, third-generation cephalosporin may effectively reduce the risk of infectious complications after transrectal ultrasound-guided prostate biopsy. Severe lower urinary tract symptoms may also be an independent risk factor for infection-related hospitalization after transrectal ultrasound-guided prostate biopsy.

What tuberculosis can teach us about combating multidrug-resistant Gram negative bacilli

There are striking similarities between the dual pandemics of multidrug-resistant tuberculosis (MDR TB) and multidrug-resistant Gram negative bacilli (MDR GNB) despite fundamental differences in the pathogenesis and epidemiology of these pathogens. In this perspective, we highlight several strategies that have been used by the global TB community to address the MDR TB problem, including approaches to: encourage appropriate use of anti-TB medications, enhance appropriate utilization of molecular diagnostic testing, facilitate development of new antimicrobial agents, and strengthen surveillance systems and infection control practices. Understanding the successes and challenges of these strategies for MDR TB control will be instructive for efforts to curb emergence and spread of MDR GNB.

Antimicrobial Resistance and Molecular Epidemiology of Escherichia coli Causing Bloodstream Infections in Three Hospitals in Shanghai, China

Escherichia coli (E. coli) is one of the most frequent and lethal causes of bloodstream infections (BSIs). We carried out a retrospective multicenter study on antimicrobial resistance and phylogenetic background of clinical E. coli isolates recovered from bloodstream in three hospitals in Shanghai. E. coli isolates causing BSIs were consecutively collected between Sept 2013 and Sept 2014. Ninety isolates randomly selected (30 from each hospital) were enrolled in the study. Antimicrobial susceptibility testing was performed by disk diffusion. PCR was used to detect antimicrobial resistance genes coding for β-lactamases (TEM, CTX-M, OXA, etc.), carbapenemases (IMP, VIM, KPC, NDM-1 and OXA-48), and phylogenetic groups. eBURST was applied for analysis of multi-locus sequence typing (MLST). The resistance rates for penicillins, second-generation cephalosporins, fluoroquinolone and tetracyclines were high (>60%). Sixty-one of the 90 (67.8%) strains enrolled produced ESBLs and no carbapenemases were found. Molecular analysis showed that CTX-M-15 (25/61), CTX-M-14 (18/61) and CTX-M-55 (9/61) were the most common ESBLs. Phylogenetic group B2 predominated (43.3%) and exhibited the highest rates of ESBLs production. ST131 (20/90) was the most common sequence type and almost assigned to phylogenetic group B2 (19/20). The following sequence types were ST405 (8/90) and ST69 (5/90). Among 61 ESBL-producers isolates, B2 (26, 42.6%) and ST131 (18, 29.5%) were also the most common phylogenetic group and sequence type. Genetic diversity showed no evidence suggesting a spread of these antimicrobial resistant isolates in the three hospitals. In order to provide more comprehensive and reliable epidemiological information for preventing further dissemination, well-designed and continuous surveillance with more hospitals participating was important.

Increasing Incidence of Extended-Spectrum β-Lactamase-Producing Escherichia coli in Community Hospitals throughout the Southeastern United States

OBJECTIVE To describe the epidemiology of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) and Klebsiella pneumoniae (ESBL-KP) infections DESIGN Retrospective cohort SETTING Inpatient care at community hospitals PATIENTS All patients with ESBL-EC or ESBL-KP infections METHODS ESBL-EC and ESBL-KP infections from 26 community hospitals were prospectively entered into a centralized database from January 2009 to December 2014. RESULTS A total of 925 infections caused by ESBL-EC (10.5 infections per 100,000 patient days) and 463 infections caused by ESBL-KP (5.3 infections per 100,000 patient days) were identified during 8,791,243 patient days of surveillance. The incidence of ESBL-EC infections increased from 5.28 to 10.5 patients per 100,000 patient days during the study period (P=.006). The number of community hospitals with ESBL-EC infections increased from 17 (65%) in 2009 to 20 (77%) in 2014. The median ESBL-EC infection rates among individual hospitals with ≥1 ESBL-EC infection increased from 11.1 infections/100,000 patient days (range, 2.2-33.9 days) in 2009 to 22.1 infections per 100,000 patient days (range, 0.66-134 days) in 2014 (P=.05). The incidence of ESBL-KP infections remained constant over the study period (P=.14). Community-associated and healthcare-associated ESBL-EC infections trended upward (P=.006 and P=.02, respectively), while hospital-onset infections remained stable (P=.07). ESBL-EC infections were more common in females (54% vs 44%, P<.001) and Caucasians (50% vs 40%, P<.0001), and were more likely to be isolated from the urinary tract (61% vs 52%, P<.0001) than ESBL-KP infections. CONCLUSIONS The incidence of ESBL-EC infection has increased in community hospitals throughout the southeastern United States, while the incidence of ESBL-KP infection has remained stable. Community- and healthcare-associated ESBL-EC infections are driving the upward trend. Infect. Control Hosp. Epidemiol. 2015;37(1):49-54.