ESBLs: A Clear and Present Danger?

Synergistic activity of Thymus capitatus essential oil and cefotaxime against ESBL-producing Klebsiella pneumoniae

The objective of the current study was to evaluate the interaction between Tunisian Thymus capitatus essential oil (EO) and cefotaxime against Extended-Spectrum Beta-lactamases (ESBLs) producing Klebsiella pneumoniae hospital strains. GC-MS revealed that the major component of EO was found to be carvacrol (69.28%). The EO exerts an advanced bactericidal effect against all strains. Synergy between EO and cefotaxime was obtained by combined disk diffusion and checkerboard techniques. Combined use of EO and cefotaxime reduced the MIC of imipenem by 8- to 128-fold for all strains (fractional inhibitory concentration index ˂ 0.5, synergy). The time kill curve assay confirmed the advanced activity of combinatory effects of EO and cefotaxime, with total reduce of bacterial number (CFU/mL) after 6 h of culture. Synergistic activity of the combination between EO and cefotaxime constitute an important strategy as therapeutical option to combat infections caused by ESBLs producing Klebsiella pneumoniae.

Semi-mechanistic modeling of resistance development to β-lactam and β-lactamase-inhibitor combinations

The use of β-lactam (BL) and β-lactamase inhibitor (BLI) combinations, such as piperacillin-tazobactam (PIP-TAZ) is an effective strategy to combat infections by extended-spectrum β-lactamase-producing bacteria. However, in Gram-negative bacteria, resistance (both mutational and adaptive) to BL-BLI combination can still develop through multiple mechanisms. These mechanisms may include increased β-lactamase activity, reduced drug influx, and increased drug efflux. Understanding the relative contribution of these mechanisms during resistance development helps identify the most impactful mechanism to target in designing a treatment to counter BL-BLI resistance. This study used semi-mechanistic mathematical modeling in combination with antibiotic sensitivity assays to assess the potential impact of different resistance mechanisms during the development of PIP-TAZ resistance in a Klebsiella pneumoniae isolate expressing CTX-M-15 and SHV-1 β-lactamases. The mathematical models were used to evaluate the potential impact of several cellular changes as a sole mediator of PIP-TAZ resistance. Our semi-mechanistic model identified 2 out of the 13 inspected mechanisms as key resistance mechanisms that may independently support the observed magnitude of PIP-TAZ resistance, namely porin loss and efflux pump up-regulation. Simulation using the resulting models also suggested the possible adjustment of PIP-TAZ dose outside its commonly used 8:1 dosing ratio. The current study demonstrated how theory-based mechanistic models informed by experimental data can be used to support hypothesis generation regarding potential resistance mechanisms, which may guide subsequent experimental studies.

Protocol for surveillance of antimicrobial-resistant bacteria causing community-acquired urinary tract infections in low-income countries

The spread of drug-resistant bacteria into the community is an urgent threat. In most low-middle-income countries (LMICs) settings, community-acquired infection (CAI) is empirically treated with no data to support the choice of antibiotics, hence contributing to resistance development. Continuous antimicrobial resistance (AMR) data on community-acquired pathogens are needed to draft empirical treatment guidelines, especially for areas with limited culture and susceptibility testing. Despite the importance of addressing antibiotic-resistant pathogens in the community setting, protocols for the surveillance of AMR bacterial infections are lacking in most (LMICs). We present a protocol for surveillance of AMR in LMICs using urinary tract infection (UTI) as a proxy for CAI to enable users to quantify and establish the drivers of AMR bacteria causing UTI. The protocol intends to assist users in designing a sustainable surveillance program for AMR in the community involving children above two years of age and adults presenting to a primary health facility for healthcare. Implementation of the protocol requires initial preparation of the laboratories to be involved, surveillance areas, selection of priority bacteria and antimicrobials to be used, and the design of a coordinated sampling plan. Recruitment should occur continuously in selected health facilities for at least 12 months to observe seasonal trends of AMR. At least 10 mL of clean-catch mid-stream urine must be collected into 20 mL calibrated sterile screw-capped universal bottles lined with 0.2 mg boric acid and transported to the testing laboratory. Utilise the data system that generates standard reports for patient care to be shared internally and externally in the regions and the world through global platforms such as the Global Antimicrobial Resistance Surveillance System.

Exploring Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli in Food-Producing Animals and Animal-Derived Foods

Antimicrobials serve as crucial treatments in both veterinary and human medicine, aiding in the control and prevention of infectious diseases. However, their misuse or overuse has led to the emergence of antimicrobial resistance, posing a significant threat to public health. This review focuses on extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in animals and their associated food products, which contribute to the proliferation of antimicrobial-resistant strains. Recent research has highlighted the presence of ESBL-producing E. coli in animals and animal-derived foods, with some studies indicating genetic similarities between these isolates and those found in human infections. This underscores the urgent need to address antimicrobial resistance as a pressing public health issue. More comprehensive studies are required to understand the evolving landscape of ESBLs and to develop strategic public health policies grounded in the One Health approach, aiming to control and mitigate their prevalence effectively.

Identification of potential inhibitor against CTX-M-3 and CTX-M-15 proteins: an in silico and in vitro study

Extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae infection is a serious global threat. ESBLs target 3rd generation cephalosporin antibiotics, the most commonly prescribed medicine for gram-negative bacterial infections. As bacteria are prone to develop resistance against market-available ESBL inhibitors, finding a novel and effective inhibitor has become mandatory. Among ESBL, the worldwide reported two enzymes, CTX-M-15 and CTX-M-3, are selected for the present study. CTX-M-3 protein was modeled, and two thousand phyto-compounds were virtually screened against both proteins. After filtering through docking and pharmacokinetic properties, four phyto-compounds (catechin gallate, silibinin, luteolin, uvaol) were further selected for intermolecular contact analysis and molecular dynamics (MD) simulation. MD trajectory analysis results were compared, revealing that both catechin gallate and silibinin had a stabilizing effect against both proteins. Silibinin having the lowest docking score, also displayed the lowest MIC (128 µg/mL) against the bacterial strains. Silibinin was also reported to have synergistic activity with cefotaxime and proved to have bactericidal effect. Nitrocefin assay confirmed that silibinin could inhibit beta-lactamase enzyme only in living cells, unlike clavulanic acid. Thus the present study validated the CTX-M inhibitory activity of silibinin both in silico and in vitro and suggested its promotion for further studies as a potential lead. The present study adopted a protocol through the culmination of bioinformatics and microbiological analyses, which will help future researchers identify more potential leads and design new effective drugs.Communicated by Ramaswamy H. Sarma.

High oral carriage of multidrug resistant Gram-negative bacilli in adolescents: the SOPKARD-Junior study

Introduction

The colonization of the oral cavity by potentially pathogenic antimicrobial-resistant bacteria in adolescents and its consequences is very poorly understood. The present study focused on the occurrence of oral colonization by Gram-negative bacilli (GNB) and their multidrug resistance, including the production of extended-spectrum β-lactamases (ESBLs) and carbapenemases, among healthy adolescents and risk factors associated with GNB colonization.

Materials and methods

This study was conducted as part of "A program for the early detection of risk factors for lifestyle diseases SOPKARD-Junior" (SOPKARD-Junior). Oral samples were collected from 182 adolescents from four public elementary schools in Sopot, Poland, aged 13-14 years. Bacterial strains were identified by the MALDI-TOF MS method. Screening of antimicrobial resistance was performed using a disk diffusion method. The NG-Test® CARBA-5 was used to detect and differentiate the five most widely distributed carbapenemases. Demographic and clinical data were collected and statistical analysis of risk factors was performed.

Results

A total of 68 out of 182 (37.4%) healthy adolescents was documented oral colonization with Gram-negative bacilli, including 50/182 (27.5%) multidrug resistant (MDR-GNB) strains. Over 60% of oral carriage concerned three main genera Enterobacter spp., Pseudomonas spp., and Serratia spp., which were detected in 22.1%, 19.1%, and 19.1% of participants, respectively. Citrobacter spp., Escherichia coli, Klebsiella spp., Hafnia spp., Aeromonas spp., Acinetobacter spp., and Stenotrophomonas spp. were also isolated. The antimicrobial resistance to ampicillin (100%), ceftazidime (69.1%), meropenem (60.3%), gentamycin (60.3%), piperacillin/tazobactam (52.9%), and piperacillin (45.6%) were the most common. Among 73.5% GNB strains multidrug resistance was observed, including all Pseudomonas spp. strains. Among MDR-GNB, 30.4% were resistant to four groups of antibiotics, half of the MDR Pseudomonas spp. strains were resistant to 10 groups of antibiotics. Extended-spectrum β-lactamases were produced by Enterobacter cloacae, Klebsiella spp., and Serratia spp. (7.4%). Colonization by ESBLs-positive GNB strains was significantly associated with recurrent respiratory infections, nasal congestion, and bronchitis (p<0.05).

Conclusion

Our study revealed high oral carriage of multi-drug resistant Gram-negative bacilli in healthy adolescents and the association of ESBL-producing strains with respiratory infections. Further studies on oral colonization with GNB are necessary due to the possibility of distinct infections and the acquisition of antibiotic resistance by resident microbiota.

A Systematic Review on the Occurrence of Antimicrobial-Resistant Escherichia coli in Poultry and Poultry Environments in Bangladesh between 2010 and 2021

Antimicrobial resistance (AMR) is a significant public health issue in Bangladesh like many other developing countries where data on resistance trends are scarce. Moreover, the existence of multidrug-resistant (MDR) Escherichia coli exerts an ominous effect on the poultry sector. Therefore, the current systematic review, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, was conducted to find out the AMR scenarios in E. coli isolates sourced from poultry and poultry environments in Bangladesh between 2010 and 2021. Following the PRISMA guidelines, a total of 17 published scientific articles were selected for this systematic review. This review revealed that 18 out of 64 districts in Bangladesh reported E. coli in poultry, having a higher prevalence (combined prevalence: 69.3%, 95% confidence interval, CI: 67.3-71%). Moreover, the prevalence ranged from 24.3% to 100%. This review found that E. coli isolates showed resistance to 14 antimicrobial classes and 45 different antimicrobial agents, including the last-line (reserve group) antibiotics and banned antimicrobial categories for the treatment of infections in agricultural animals. Phenotypic resistance of E. coli against penicillins and beta-lactamase inhibitors (20.2%-100%), cephalosporins (1.9%-100%), fluoroquinolones (5.98%-100%), aminoglycosides (6%-100%), tetracyclines (17.7%-100%), carbapenems (13.6%-72.7%), macrolides (11.8%-100%), polymyxins (7.9%-100%), phenicols (20%-97.2%), sulfa drugs (44.7%-100%), cephamycins (21.4%-48.8%), nitrofurans (21.4%-63.2%), monobactams (1.2%), and glycylcyclines (2.3%) was recorded in the last decades in Bangladesh. Also, 14 articles reported MDR E. coli in poultry, including a 100% MDR in nine articles and a 92.7% (95% CI: 91.2-94%) combined percentage of MDR E. coli isolates. Twenty-four different AMR genes encoding resistance to beta-lactams (bla _TEM, bla _CTX-M-1, bla _CTX-M-2, bla _CTX-M-9, bla _OXA-1, bla _OXA-47, bla _SHV, and CITM), colistin (mcr1 and mcr3), fluoroquinolones (qnrB and qnrS), tetracyclines (tetA, tetB, and tetC), sulfonamides (sulI and sulII), trimethoprim (dfrA1), aminoglycosides (rmtB), streptomycin (aadA1), gentamicin (aac-3-IV), erythromycin (ereA), and chloramphenicol (catA1 and cmlA) were detected in E. coli isolates. The presence of MDR E. coli and their corresponding resistance genes in poultry and poultry environments is an alarming issue for all health communities in Bangladesh. We suggest a regular antimicrobial surveillance program with a strong One Health approach to lessen the hazardous effects of AMR E. coli in poultry industries in Bangladesh.

No more tears from surgical site infections in interventional pain management

As the field of interventional pain management (IPM) grows, the risk of surgical site infections (SSIs) is increasing. SSI is defined as an infection of the incision or organ/space that occurs within one month after operation or three months after implantation. It is also common to find patients with suspected infection in an outpatient clinic. The most frequent IPM procedures are performed in the spine. Even though primary pyogenic spondylodiscitis via hematogenous spread is the most common type among spinal infections, secondary spinal infections from direct inoculation should be monitored after IPM procedures. Various preventive guidelines for SSI have been published. Cefazolin, followed by vancomycin, is the most commonly used surgical antibiotic prophylaxis in IPM. Diagnosis of SSI is confirmed by purulent discharge, isolation of causative organisms, pain/tenderness, swelling, redness, or heat, or diagnosis by a surgeon or attending physician. Inflammatory markers include traditional (C-reactive protein, erythrocyte sedimentation rate, and white blood cell count) and novel (procalcitonin, serum amyloid A, and presepsin) markers. Empirical antibiotic therapy is defined as the initial administration of antibiotics within at least 24 hours prior to the results of blood culture and antibiotic susceptibility testing. Definitive antibiotic therapy is initiated based on the above culture and testing. Combination antibiotic therapy for multidrug-resistant Gram-negative bacteria infections appears to be superior to monotherapy in mortality with the risk of increasing antibiotic resistance rates. The never-ending war between bacterial resistance and new antibiotics is continuing. This article reviews prevention, diagnosis, and treatment of infection in pain medicine.

Antimicrobial resistance, virulence associated genes and phylogenetic background versus plasmid replicon types: the possible associations in avian pathogenic Escherichia coli (APEC)

BACKGROUND

Antimicrobial resistance (AMR) in bacterial isolates from food producing animals not only challenges the preventive and therapeutic strategies in veterinary medicine, but also threatens public health. Genetic elements placed on both chromosome and plasmids could be involved in AMR. In the present study, the associations of genomic backbone and plasmids with AMR were evaluated. We also provided some primary evidences that which genetic lineages potentially host certain groups of plasmids.

RESULTS

In the current study, 72 avian pathogenic Escherichia coli (APEC) strains were examined. Isolates resistant to tetracycline and trimethoprim-sulfamethoxazole (87.5%; each), and harboring bla_TEM (61.1%) were dominant. Moreover, phylogroup D was the most prevalent phylogroup in total (23.6%), and among multidrug-resistant (MDR) isolates (14/63). The most prevalent Inc-types were also defined as follows: IncP (65.2%), IncI1 (58.3%), and IncF group (54.1%). Significant associations among phylogroups and AMR were observed such as group C to neomycin (p = 0.002), gentamicin (p = 0.017) and florfenicol (p = 0.036). Furthermore, group D was associated with bla_CTX. In terms of associations among Inc-types and AMR, resistance to aminoglycoside antibiotics was considerably linked with IncP (p = 0.012), IncI1 (p = 0.038) and IncA/C (p = 0.005). The bla_TEM and bla_CTX genes presence were connected with IncI1 (p = 0.003) and IncFIC (p = 0.013), respectively. It was also shown that members of the D phylogroup frequently occured in replicon types FIC (8/20), P (13/47), I1 (13/42), HI2 (5/14) and L/M (3/3).

CONCLUSIONS

Accorging to the results, it seems that group D strains have a great potential to host a variety of plasmids (Inc-types) carrying different AMR genes. Thus, based on the results of the current study, phyogroup D could be a potential challenge in dealing with AMR in poultry. There were more strong correlations among Inc-types and AMR compared to phylotypes and AMR. It is suggested that in epidemiological studies on AMR both genomic backbone and major plasmid types should be investigated.

Biogenic Silver Nanoparticles Strategically Combined With Origanum vulgare Derivatives: Antibacterial Mechanism of Action and Effect on Multidrug-Resistant Strains

Multidrug-resistant bacteria have become a public health problem worldwide, reducing treatment options against several pathogens. If we do not act against this problem, it is estimated that by 2050 superbugs will kill more people than the current COVID-19 pandemic. Among solutions to combat antibacterial resistance, there is increasing demand for new antimicrobials. The antibacterial activity of binary combinations containing bioAgNP (biogenically synthesized silver nanoparticles using Fusarium oxysporum), oregano essential oil (OEO), carvacrol (Car), and thymol (Thy) was evaluated: OEO plus bioAgNP, Car plus bioAgNP, Thy plus bioAgNP, and Car plus Thy. This study shows that the mechanism of action of Thy, bioAgNP, and Thy plus bioAgNP involves damaging the membrane and cell wall (surface blebbing and disruption seen with an electron microscope), causing cytoplasmic molecule leakage (ATP, DNA, RNA, and total proteins) and oxidative stress by enhancing intracellular reactive oxygen species and lipid peroxidation; a similar mechanism happens for OEO and Car, except for oxidative stress. The combination containing bioAgNP and oregano derivatives, especially thymol, shows strategic antibacterial mechanism; thymol disturbs the selective permeability of the cell membrane and consequently facilitates access of the nanoparticles to bacterial cytoplasm. BioAgNP-treated Escherichia coli developed resistance to nanosilver after 12 days of daily exposition. The combination of Thy and bioAgNP prevented the emergence of resistance to both antimicrobials; therefore, mixture of antimicrobials is a strategy to extend their life. For antimicrobials alone, minimal bactericidal concentration ranges were 0.3-2.38 mg/ml (OEO), 0.31-1.22 mg/ml (Car), 0.25-1 mg/ml (Thy), and 15.75-31.5 μg/ml (bioAgNP). The time-kill assays showed that the oregano derivatives acted very fast (at least 10 s), while the bioAgNP took at least 30 min to kill Gram-negative bacteria and 7 h to kill methicillin-resistant Staphylococcus aureus (MRSA). All the combinations resulted in additive antibacterial effect, reducing significantly minimal inhibitory concentration and acting faster than the bioAgNP alone; they also showed no cytotoxicity. This study describes for the first time the effect of Car and Thy combined with bioAgNP (produced with F. oxysporum components) against bacteria for which efficient antimicrobials are urgently needed, such as carbapenem-resistant strains (E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa) and MRSA.

Antibiotic-functionalized gold nanoparticles for the detection of active β-lactamases

Antimicrobial resistance (AMR) continues to threaten the effective treatment and prevention of bacterial infections. The spread of resistant infections is accelerated by the lack of fast and cost-effective tests for the detection of AMR at the point-of-care. We aimed to address this challenge by developing a diagnostic tool to detect one of the major forms of AMR, the β-lactamase enzymes. Antibiotic-functionalized gold nanoparticles (AuNPs) have been successfully developed for the detection of β-lactamases in challenging biological media, namely undiluted urine. Furthermore, these tools are compatible with samples containing a urine sample preservative (boric acid) or hematuria (blood). The functionalized AuNPs interact with the active β-lactamases, resulting in the hydrolysis of the surface-bound antibiotics, which then inhibits binding of the AuNPs to a capture protein (a penicillin-binding protein) to indicate the presence of active β-lactamases. We successfully integrated the antibiotic-functionalized AuNPs into a new lateral flow assay (LFA), which can be used to detect active β-lactamases down to the detection limit of 11 nM. While we demonstrate the use of antibiotic-functionalized AuNPs in an LFA format to provide a novel method of detecting active β-lactamases, these functionalized AuNPs are amenable to a range of alternative diagnostic technologies and could lead to vital point-of-care diagnostics for the early detection of multi-drug resistant infections.

Plethora of Resistance Genes in Carbapenem-Resistant Gram-Negative Bacteria in Greece: No End to a Continuous Genetic Evolution

Carbapenem-resistant Gram-negative bacteria are a public health threat that requires urgent action. The fact that these pathogens commonly also harbor resistance mechanisms for several other antimicrobial classes further reduces patient treatment options. The present study aimed to provide information regarding the multidrug resistance genetic background of carbapenem-resistant Gram-negative bacteria in Central Greece. Strains from a tertiary care hospital, collected during routine practice, were characterized using a DNA microarray-based assay. Various different resistance determinants for carbapenems, other beta-lactams, aminoglycosides, quinolones, trimethoprim, sulfonamides and macrolides were detected among isolates of the same sequence type. Eighteen different multidrug resistance genomic profiles were identified among the twenty-four K. pneumoniae ST258, seven different profiles among the eight K. pneumoniae ST11, four profiles among the six A. baumannii ST409 and two among the three K. oxytoca. This report describes the multidrug resistance genomic background of carbapenem-resistant Gram-negative bacteria from a tertiary care hospital in Central Greece, providing evidence of their continuous genetic evolution.

Carriage of ESBL-producing Enterobacterales in wastewater treatment plant workers and surrounding residents - the AWARE Study

To investigate whether wastewater treatment plant (WWTP) workers and residents living in close proximity to a WWTP have elevated carriage rates of ESBL-producing Enterobacterales, as compared to the general population. From 2018 to 2020, we carried out a cross-sectional study in Germany, the Netherlands, and Romania among WWTP workers (N = 344), nearby residents (living ≤ 300 m away from WWTPs; N = 431) and distant residents (living ≥ 1000 m away = reference group; N = 1165). We collected information on potential confounders via questionnaire. Culture of participants' stool samples was performed with ChromID®-ESBL agar plates and species identification with MALDI-TOF-MS. We used logistic regression to estimate the odds ratio (OR) for carrying ESBL-producing E. coli (ESBL-EC). Sensitivity analyses included stratification by country and interaction models using country as secondary exposure. Prevalence of ESBL-EC was 11% (workers), 29% (nearby residents), and 7% (distant residents), and higher in Romania (28%) than in Germany (7%) and the Netherlands (6%). Models stratified by country showed that within the Romanian population, WWTP workers are about twice as likely (aOR = 2.34, 95% CI: 1.22-4.50) and nearby residents about three times as likely (aOR = 3.17, 95% CI: 1.80-5.59) to be ESBL-EC carriers, when compared with distant residents. In stratified analyses by country, we found an increased risk for carriage of ESBL-EC in Romanian workers and nearby residents. This effect was higher for nearby residents than for workers, which suggests that, for nearby residents, factors other than the local WWTP could contribute to the increased carriage.

Prevalence of Extended Spectrum Beta-Lactamase Producing Gram-Negative Bacilli causing Surgical Site Infections in a Tertiary Care Centre

Hospital-acquired infections (HAIs) are continuing to be a major risk in health care settings. World Health Organization (WHO) describes surgical site infections (SSIs) as one among the major health issue, causing enormous burden to both patients as well as doctors. Multidrug-resistant pathogens that cause SSIs continue to be an ongoing and increasing challenge to health care settings. The objective of the present study was to know the prevalence of extended-spectrum beta-lactamase (ESBL) producing gram-negative bacilli causing SSIs at a tertiary healthcare facility. The present cross-sectional observational study was done for a period of one year. Pus samples from clinically suspected cases of SSIs were collected and subjected to bacterial culture and sensitivity testing. From the total of 140 samples collected, a total of 138 bacterial isolates were isolated. Out of 138 isolates, 85 isolates (61.6%) were identified as gram-negative bacilli of which 33 isolates (38.8%) were identified to be ESBL phenotypes. Majority of the ESBL phenotypes were Escherichia coli (25.9%) followed by Klebsiella pneumoniae (7%), Acinetobacter species (2.4%), Pseudomonas aeruginosa (2.4%) and Proteus species (1.2%). Regular surveillance of antibiotic sensitivity pattern and screening for beta-lactamase production should be done which helps to know the trends of pathogenic bacteria causing SSI and guides in planning antibiotic therapy.

Genetic relatedness in extended-spectrum beta-lactamase-producing Escherichia coli from clinical isolates using enterobacterial repetitive intergenic consensus polymerase chain reaction

OBJECTIVES

The aim of this study is to determine the genetic relatedness of extended-spectrum beta-lactamases (ESBL)-producing Escherichia coli using the enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) technique.

METHODS

Suspected Gram-negative bacteria with their identities from the clinical samples were confirmed using Microgen GN-A-ID Kit. The double-disc synergy test was used to confirm for ESBL-producing E. coli. The susceptibility of the organisms was tested against eleven antimicrobial agents. A singleplex PCR assay was carried out targeting TEM, SHV, CTX-M, and OXA. ERIC-PCR performed, and band patterns obtained were visually evaluated. A dendrogram of the ERIC-PCR fingerprint pattern was done with the aid of DendroUPGMA using the cluster method.

RESULTS

Of the 576 clinical samples collected, 23 isolates were confirmed E. coli, and all (100%) are ESBL producers. The highest antibiotic resistance rate was recorded in cefixime (95.6%), and the least was amikacin (17.4%). The predominant ESBL gene is blaTEM genes (95.6%). Gel analysis of ERIC-PCR revealed 1-6 bands. The profiles of the ERIC-PCR differentiated the 23 E. coli isolates into four ERIC cluster types.

CONCLUSION

More than 80% of the isolates are sensitive to amikacin, with greater than 95% harboring blaTEM genes. Overall, ERIC obtained from the clinical specimens indicated some evidence in the genetic relatedness of the ESBL genes among E. coli isolates.

Conjugative Plasmid-Mediated Extended Spectrum Cephalosporin Resistance in Genetically Diverse Escherichia coli from a Chicken Slaughterhouse

ESC-resistant E. coli isolates were collected from broiler chickens, a slaughterhouse, and retail meat to assess their dispersion and their involvement in cross-contamination. ESBL-/AmpC-producing E. coli were isolated during the slaughter process of all six investigated chicken flocks from scalding, feather removal, first conveyor, evisceration, second washing, third conveyor, and third washing areas, and from handling workers in the slaughterhouse. ESC-resistant E. coli isolates with the same pulsed-field gel electrophoresis type were found in the same site (scalding) on different sampling days. ESBL/AmpC-producing E. coli isolates were absent in the lairage area in the slaughterhouse, but present in the retail markets in 36.8% (7/19) of the chicken flocks. The bla_CTX-M genes and bla_CMY-2 were conjugated to recipient E. coli J53 in 67.5% (27/40) and 56.1% (23/41) of ESBL-producing and AmpC-producing E. coli isolates, respectively. The presence of the same conjugative plasmids was found in genetic diversity ESC-resistant E. coli colonies collected on different sampling days. Our study emphasizes that cross-contamination of ESBL/AmpC-producing E. coli in slaughterhouse has a crucial impact on the occurrence of ESC resistance in retail chicken meat.

Genetic Characterization of CTX-M-2-Producing Klebsiella pneumoniae and Klebsiella oxytoca Associated With Bovine Mastitis in Japan

CTX-M-2-producing Klebsiella oxytoca (K. oxytoca) has not received much attention in animal husbandry compared with Klebsiella pneumoniae (K. pneumoniae), a major reservoir of extended-spectrum β-lactamase (ESBL) genes. Bacteriological examinations of 1,466 mastitic milk samples between October 2012 and December 2014 were conducted. Ninety-five K. pneumoniae isolates (total prevalence: 6.5%) and 81 K. oxytoca isolates (total prevalence: 5.5%) were obtained. Seventeen K. pneumoniae isolates obtained from 15 animals reared on 11 farms and 9 K. oxytoca isolates obtained from 9 animals reared on the same farm were phenotypically confirmed to be ESBL producers. All nine ESBL-producing K. oxytoca isolates were obtained from one farm between June and November 2013 and related to a significantly (p < 0.05) higher monthly prevalence of mild mastitis (in June, August, September, October, and November 2013). Pulsed-field gel electrophoresis (PFGE) patterns of ESBL-producing K. pneumoniae isolates were distinguished from each other by more than 6-band differences except for two isolates from two animals, whereas all nine K. oxytoca isolates showed an identical PFGE pattern. Transferability of the bla _CTX-M-2 gene was found in 14 K. pneumoniae and 9 K. oxytoca isolates by conjugation analysis. Of these isolates, the bla _CTX-M-2 gene was detected on plasmids belonging to the incompatibility (Inc) groups P and N derived from five K. pneumoniae and nine K. oxytoca isolates, respectively, although the plasmids from the remaining nine K. pneumoniae were untypeable. All the transconjugants exhibited elevated minimum inhibitory concentrations of ampicillin, cefotaxime, and ceftiofur compared with those in the wild-type, recipient strain. Restriction fragment length polymorphism analysis demonstrated that the IncN plasmids extracted from eight of nine transconjugants, which received resistance against β-lactams from K. oxytoca, showed an identical DraI digestion pattern. These results suggest that the CTX-M-2-producing K. oxytoca strain with the above-mentioned characteristics may have clonally spread within a farm, whereas the bla _CTX-M-2 gene in K. pneumoniae possibly disseminated among the farms through different plasmids. Thus, monitoring of ESBL genes, including the bla _CTX-M-2 gene, among causative agents of bacterial mastitis in cows can help to develop relevant treatments and control practices.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation

INTRODUCTION

Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality.

AREAS COVERED

This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials.

EXPERT OPINION

Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

High Carriage Rate of Extended-Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella Species among Poultry Meat Vendors in Dar es Salaam: The Urgent Need for Intervention to Prevent the Spread of Multidrug-Resistant Pathogens

Background

Bacteria possessing extended-spectrum beta-lactamase (ESBL), especially E. coli and Klebsiella species, are problematic, particularly in hospitalized patients. Poultry meat vendors are at risk of carrying ESBL-producing bacteria when processing and handling meat products in an unhygienic environment. There is limited information on the carriage rate of ESBL-producing pathogens among poultry meat vendors that necessitated the conduction of the study.

Method

A cross-sectional study was conducted among poultry meat vendors in Dar es Salaam, Tanzania. Participants provided rectal swabs in transport media upon instruction. The primary isolation of ESBL-producing bacteria was carried out using MacConkey agar supplemented with ceftazidime. Identification of isolates relied on conventional methods. Double-disk synergy was the method used to confirm ESBL-producing isolates. We performed descriptive statistics using Statistical Package for Social Sciences version 23. A p value < 0.05 was considered statistically significant.

Results

A total of 300 participants were recruited from five districts, with a mean age of 27.2 ± 6.7 years. The majority was male (67.3%), and 74.7% worked as poultry meat vendors for more than one year. Out of 300 participants, 107 (35.7%) had confirmed ESBL-producing E. coli and Klebsiella spp. The majority of confirmed ESBL-producing isolates was E. coli (78.5%). Participants from Ubungo District had significantly higher carriage of ESBL-producing Escherichia coli and Klebsiella spp. (48.0%, 95% CI: 34.8–47.7) than Temeke District (21.4%, 95% CI: 13.4–32.4). Only 28.0% of participants had access to latrines at the workplace, and all working areas lacked access to running water.

Conclusion

The study revealed a relatively high fecal carriage rate of ESBL-producing E. coli and Klebsiella spp. among poultry meat vendors. Poor working environments and hygienic practices are risks for spread of these multidrug-resitant pathogens.

Detection of Cephalosporin and Fluoroquinolone Resistance Genes via Novel Multiplex qPCR in Fecal Salmonella Isolates From Northern Californian Dairy Cattle, 2002-2016

The objectives of this study were to evaluate the prevalence of extended spectrum β-lactamase (ESBL) genes, AmpC-type β-lactamase (ACBL) genes, and plasmid mediated quinolone resistance (PMQR) genes in Salmonella isolated at a Veterinary Medical Teaching Hospital microbiology laboratory, examine trends in presence of these resistance genes, and to explore the correlation between phenotypic resistance and presence of specific genes. The presence of ESBL, ACBL, and PMQR genes were detected using a single, novel multiplex qPCR. Only the genes bla_CMY–2 and bla_TEM were detected in the 110 Salmonella isolates tested. PMQR genes were not detected in isolates screened. Of 94 third-generation cephalosporin resistant isolates, representing eight serotypes, 48% (n = 45) were positive for bla_CMY–2 only and 50% (n = 47) were simultaneously positive for bla_CMY–2 and bla_TEM. Two third-generation cephalosporin resistant isolates were tested negative for all β-lactamase genes in our qPCR assay and likely house ESBL genes not screened for by our qPCR assay. A logistic regression model revealed that for serotype Dublin isolates (n = 38) the odds ratio for testing positive for bla_TEM when compared to all other serotypes was 51.6 (95% CI: 4.01–664.03, p = 0.0029). For serotype Typhimurium (n = 9) the odds ratio for testing positive for bla_TEM when compared to all other serotypes was 43.3 (95% CI: 1.76–1000, p = 0.0216). Overall, our results suggest that the prevalence of resistance to cephalosporins and fluoroquinolones due to ESBLs, ACBLs, and PMQR genes present in bovine nontyphoidal Salmonella enterica isolates has remained relatively constant in the isolates screened over a 14-year period.

Synergistic effect of ampicillin and dihydrobenzofuran neolignans (myticaganal C) identified from the seeds of Myristica fragrans Houtt. against Escherichia coli

The present study was designed to enhance the antibacterial activity of ampicillin against Escherichia coli by combining it with myticaganal C. Antibacterial activity of ampicillin combined with myticaganal C against E. coli was assessed by agar well diffusion. Minimum inhibitory concentrations (MICs) and synergy by checkerboard assay of ampicillin and myticaganal C were assessed by resazurin-based 96-well microdilution. Bacterial responses were assessed by flow cytometry. Ampicillin in combination with myticaganal C showed better zone of inhibition (31.67 ± 0.58 mm) than myticaganal C or ampicillin alone. MIC of ampicillin was found to be 12.5 μg/mL, but myticaganal C was ineffective against E. coli. Myticaganal C (8000 μg/mL) with ampicillin (0.0975 μg/mL) exhibited strong synergy, so the need for ampicillin was reduced 128-fold. Combination inhibited E. coli by acting on cell membrane and by granularity disruptions. These findings indicate that myticaganal C enhances the potential of ampicillin against E. coli, thus providing an effective alternative to deal with the problem of bacterial resistance.

Genome-based characterization of two Colombian clinical Providencia rettgeri isolates co-harboring NDM-1, VIM-2, and other β-lactamases

BACKGROUND

Providencia rettgeri is a nosocomial pathogen associated with urinary tract infections and related to Healthcare-Associated Infection (HAI). In recent years isolates producing New Delhi Metallo-β-lactamase (NDM) and other β-lactamases have been reported that reduce the efficiency of clinical antimicrobial treatments. In this study, we analyzed antibiotic resistance, the presence of resistance genes and the clonal relationship of two P. rettgeri isolates obtained from male patients admitted to the same hospital in Bogotá - Colombia, 2015.

RESULTS

Antibiotic susceptibility profile evaluated by the Kirby-Bauer method revealed that both isolates were resistant to third-generation carbapenems and cephalosporins. Whole-genome sequencing (Illumina HiSeq) followed by SPAdes assembling, Prokka annotation in combination with an in-house Python program and resistance gene detection by ResFinder identified the same six β-lactamase genes in both isolates: blaNDM-1, blaVIM-2, blaCTX-M-15, blaOXA-10, blaCMY-2 and blaTEM-1. Additionally, various resistance genes associated with antibiotic target alteration (arnA, PmrE, PmrF, LpxA, LpxC, gyrB, folP, murA, rpoB, rpsL, tet34) were found and four efflux pumps (RosAB, EmrD, mdtH and cmlA). The additional resistance to gentamicin in one of the two isolates could be explained by a detected SNP in CpxA (Cys191Arg) which is involved in the stress response of the bacterial envelope. Genome BLAST comparison using CGView, the ANI value (99.99%) and the pangenome (using Roary) phylogenetic tree (same clade, small distance) showed high similarity between the isolates. The rMLST analysis indicated that both isolates were typed as rST-61,696, same as the RB151 isolate previously isolated in Bucaramanga, Colombia, 2013, and the FDAARGOS_330 isolate isolated in the USA, 2015.

CONCLUSIONS

We report the coexistence of the carbapenemase genes blaNDM-1, and blaVIM-2, together with the β-lactamase genes blaCTX-M-15, blaOXA-10, blaCMY-2 and blaTEM-1, in P. rettgeri isolates from two patients in Colombia. Whole-genome sequence analysis indicated a circulation of P. rettgeri rST-61,696 strains in America that needs to be investigated further.

Synthesis and biochemical evaluation of cephalosporin analogues equipped with chemical tethers

Molecular probes typically require structural modifications to allow for the immobilisation or bioconjugation with a desired substrate but the effects of these changes are often not evaluated. Here, we set out to determine the effects of attaching functional handles to a first-generation cephalosporin. A series of cephalexin derivatives was prepared, equipped with chemical tethers suitable for the site-selective conjugation of antibiotics to functionalised surfaces. The tethers were positioned remotely from the β-lactam ring to ensure minimal effect to the antibiotic's pharmacophore. Herein, the activity of the modified antibiotics was evaluated for binding to the therapeutic target, the penicillin binding proteins, and shown to maintain binding interactions. In addition, the deactivation of the modified drugs by four β-lactamases (TEM-1, CTX-M-15, AmpC, NDM-1) was investigated and the effect of the tethers on the catalytic efficiencies determined. CTX-M-15 was found to favour hydrolysis of the parent antibiotic without a tether, whereas AmpC and NDM-1 were found to favour the modified analogues. Furthermore, the antimicrobial activity of the derivatives was evaluated to investigate the effect of the structural modifications on the antimicrobial activity of the parent drug, cephalexin.

Tethered β-lactam antibiotics provide insights into designing chemical tools to target specific β-lactamases.

Efficacy of six disinfection methods against extended-spectrum beta-lactamase (ESBL) producing E. coli on eggshells in vitro

The presence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli on poultry products is an important issue for veterinary and human health due to the zoonotic infection risk for producers and consumers. The present study focuses on testing the efficacy of six different disinfection methods on eggshell samples, aiming to reduce ESBL producing E. coli contamination on the hatching egg. Sterile eggshell cutouts were artificially contaminated with 10⁸ cfu/ml CTX-M-1 producing E. coli and used as a carrier model to analyze the efficacy of six disinfection methods. The contaminated samples were separated into two groups; 1) contaminated and disinfected, 2) contaminated and non-disinfected. Six independent disinfection protocols were performed following product specifications and protocols. Each eggshell sample was separately crushed, and the total viable bacterial count was calculated to determine the disinfection efficacy. Five out of six tested methods (formaldehyde gassing, hydrogen peroxide + alcohol spray, essential oils spray, peracetic acid foam, and low energetic electron radiation) demonstrated a reduction or completely eliminated the initial ESBL producing E. coli contamination. One method (essential oils as cold fog) only partly reached the expected efficacy threshold (reduction of >10² cfu/ml) and the result differed significantly when compared to the reference method i.e. formaldehyde gassing.

Comparison between Exposure of Ciprofloxacin and Cefotaxime on Developing of Escherichia coli ESBL

This study aimed to compare ciprofloxacin and cefotaxime exposure to develop ESBL producing Escherichia coli (E. coli). A total of 16 isolates of cefotaxime sensitive E. coli and ciprofloxacin were exposed to ciprofloxacin and cefotaxime for 14 days using the Kirby-Bauer antibiotic disc diffusion method. Colonies that grew on the edge of the inhibiting zone were exposed each day by the same method. Furthermore, we observed the occurrence of resistance to cefotaxime as ESBL screening test. Isolates were resistant, the following day the ESBL was confirmed by the Modified Double Disk Sinergy Test (MDDST) method using Cefotaxime (CTX), Ceftazidime (CAZ), Aztreonam (ATM), and Amoxilin Clavulanate (AMC) antibiotic discs. From 16 isolates of ESBL producing E. coli exposed to ciprofloxacin, it was obtained 4 (25%) to ESBL E. coli. ESBL production occurred after E. coli was exposed to ciprofloxacin on days 5, 6, 7, and 12. While those exposed to cefotaxime none becomes ESBL E. coli. There was no difference between ciprofloxacin and cefotaxime exposure to develop ESBL producing E. coli (p=0.101; Chi-square).

Synergistic antibacterial and anti-biofilm activity of nisin like bacteriocin with curcumin and cinnamaldehyde against ESBL and MBL producing clinical strains

Bacteriocins are small peptides that can inhibit the growth of a diverse range of microbes. There is a need to identify bacteriocins that are effective against biofilms of resistant clinical strains. The present study focussed on the efficacy of purified nisin like bacteriocin-GAM217 against extended spectrum β-lactamase (ESBL) and metallo-beta-lactamase (MBL) producing clinical strains. Bacteriocin-GAM217 when combined with curcumin and cinnamaldehyde, synergistically enhanced antibacterial activity against planktonic and biofilm cultures of Staphylococcus epidermidis and Escherichia coli. Bacteriocin-GAM217 and phytochemical combinations inhibited biofilm formation by >80%, and disrupted the biofilm for selected ESBL and MBL producing clinical strains. The anti-adhesion assay showed that these combinatorial compounds significantly lowered the attachment of bacteria to Vero cells and that they elicited membrane permeability and rapid killing as viewed by confocal microscopy. This study demonstrates that bacteriocin-GAM217 in combination with phytochemicals can be a potential anti-biofilm agent and thus has potential for biomedical applications.

Pharmacokinetic/Pharmacodynamic Determination and Preclinical Pharmacokinetics of the β-Lactamase Inhibitor ETX1317 and Its Orally Available Prodrug ETX0282

Increasingly resistant Enterobacteriaceae have emerged as a health threat in both hospital and community settings. Infections of the urinary tract, once often treated with oral agents in the community, are requiring increased hospitalization and use of intravenously administered agents for effective treatment. These isolates often carry extended spectrum β-lactamases (ESBLs) and carbapenemases that necessitate the need for an inhibitor to cover a broad range of β-lactamases. ETX1317 is a novel diazabicyclooctane class serine β-lactamase inhibitor that restores the antibacterial activity of several classes of β-lactams, including third-generation cephalosporins such as cefpodoxime. ETX1317 is currently being developed as an orally available prodrug, ETX0282, to be administered with cefpodoxime proxetil (CPDP). The combination has demonstrated oral efficacy in murine models of infection. Pharmacokinetics established in preclinical species and pharmacokinetic/pharmacodynamic attributes suggest the orally administered combination ETX0282 + CPDP could serve as an effective treatment option against contemporary ESBL and carbapenemase-producing Enterobacteriaceae.

Genomic Epidemiology of an Outbreak of Klebsiella pneumoniae ST471 Producing Extended-Spectrum β-Lactamases in a Neonatal Intensive Care Unit

Purpose

Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBLs) causes nosocomial infections worldwide. The present study aimed to determine the molecular subtyping characteristics and antibiotic resistance mechanisms of ESBL-producing K. pneumoniae strains collected during an outbreak. Moreover, we attempted to reveal the fine transmission route of the strains within this outbreak using whole-genome sequencing (WGS).

Methods

Collecting cases and strain information were carried out. Outbreak-related strains were identified using pulsed-field gel electrophoresis (PFGE). The antibiotic susceptibility, drug-resistant genes, and molecular subtype characteristics of ESBL-producing K. pneumoniae were analyzed. The fine transmission route of the strains within this outbreak was revealed using WGS and minimum core genome (MCG) sequence typing.

Results

In mid-January, 2015, five cases of neonatal pneumonia caused by ESBL-producing K. pneumoniae were observed in the neonatal intensive care unit (NICU) of the Affiliated Hospital of Chifeng University, China. Eight ESBL-producing K. pneumoniae were isolated from these five cases, and two additional strains from another two cases were identified using PFGE. All ten isolates harbored bla _CTX-M-15, bla _TEM-1, bla _SHV-108, and bla _OXA-1 genes, and belonged to the sequence type 471 (ST471) clone. A putative transmission map was constructed via comprehensive consideration of genomic and epidemiological information. WGS identified the initial case and the "superspreader". The genomic epidemiological investigation revealed that the outbreak was caused by the introduction of the bacteria one month before the first case appeared.

Conclusion

As far as we know, this is the first report to describe the characteristics of an ST471 ESBL-producing K. pneumoniae outbreak. The data showed that epidemiological inferences could be greatly improved by interpretation in the context of WGS and that K. pneumoniae strains isolated from the same outbreak contain sufficient genomic differences to refine epidemiological linkages on the basis of genetic lineage. These findings suggested that integration of genomic and epidemiological data can help us to have a clearer understanding of when and how outbreaks occur, so as to better control nosocomial transmission.

Antimicrobial and Light-Enhanced Antimicrobial Activities, Cytotoxicity and Chemical Variability of All Tunisian Eryngium Species

This study was performed on all Eryngium species growing in Tunisia in order to evaluate their intra and interspecies variabilities and to investigate their biological activities. These species are used in traditional medicine, and literature about the phytochemical investigations of most of them is scarce. Antimicrobial and light-enhanced activities were tested against multiresistant microorganisms and extended spectrum beta-lactamase producing bacteria (ESBL). All studied species showed antimicrobial effect with several MIC values lower than 70 μg/ml. Tested Eryngium species have proven to be a promising source of photoactive compounds, while light-enhanced activity offers an alternative for the inactivation of pathogenic microorganisms which is currently subjected to a great interest. This is the first report of this activity in genus Eryngium. A significant improvement of antimicrobial activity with UV irradiation was observed, mainly for E. dichotomum, E. ilicifolium and E. triquetrum. Cytotoxicity, studied for the first time for the most species, was evaluated against cancer (J774) and non-cancer (WI38) human cell lines. Chemical composition of volatile compounds presented in the most active crude extracts (petroleum ether extracts) of the aerial parts was investigated using GC/MS analysis and was submitted to statistical analyses. It revealed their high content of bioactive phytochemicals, particularly oxygenated sesquiterpenes like spathulenol, ledol and α-bisabolol but also hydrocarbon sesquiterpenes such as β-bisabolene and copaene, as well as polyacetylene derivatives such as falcarinol. Statistical analyses permitted to evaluate the interrelations between all Tunisian Eryngium species.

Spreading of extended-spectrum β-lactamase-producing Escherichia coli ST131 and Klebsiella pneumoniae ST11 in patients with pneumonia: a molecular epidemiological study

Supplemental Digital Content is available in the text

Background:

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clinical characteristics and molecular epidemiology of ESBL-producing E. coli and K. pneumoniae causing pneumonia at a large teaching hospital in China.

Methods:

We collected patient's clinical data and ESBL-producing E. coli and K. pneumoniae strains causing pneumonia (from December 2015 to June 2016) at a hospital in Wuhan. The susceptibilities, multi-locus sequence typing, homologous analysis, ESBL genes by polymerase chain reaction and sequencing were determined.

Results:

A total of 59 ESBL-producing strains (31 E. coli and 28 K. pneumoniae) isolated from patients with pneumonia were analyzed. The majority of strains were isolated from patients were with hospital-acquired pneumonia (37/59, 62.7%), followed by community-acquired pneumonia (13/59, 22.0%), and ventilator-related pneumonia (9/59, 15.3%). The E. coli ST131 (9 isolates, 29.0%) and K. pneumoniae ST11 (5 isolates, 17.9%) were the predominant sub-types. The most prevalent ESBL gene was CTX-M-14, followed by SHV-77, CTX-M-3, SHV-11, and CTX-M-27. At least 33 (55.9%) of the ESBL-producing strains carried two or more ESBL genes. The ISEcp1 and IS26 were found upstream of all blaCTX-M (CTX-Ms) and of most blaSHV (SHVs) (57.6%), respectively. Moreover, three ESBL-producing K. pneumoniae ST11 strains which were resistant to carbapenems carried the bla_NDM-1 and bla_KPC-2, two of which also bearing bla_OXA-48 were resistant to all antibiotics (including Tigecycline).

Conclusions:

Hospital-acquired pneumonia is more likely correlated with ESBL-producing E. coli and K. pneumoniae. ESBL-producing E. coli ST131 and multi-drug resistance ESBL-producing, as well as New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemases-2 (KPC-2) bearing K. pneumoniae ST11 are spreading in patients with pneumonia in hospital.

Assessment of extended-spectrum β-lactamase (ESBLs) - producing Escherichia coli from minced meat of cattle and swab samples and hygienic status of meat retailer shops in Jimma town, Southwest Ethiopia

BACKGROUND

The impact of animals sources of food as a possible reservoir for extended-spectrum β-lactamase (ESBL) - Producing E. coli, and the dissemination of such strains into the food production chain need to be assessed. This study was aimed to assess the presence and antimicrobial susceptibility patterns of ESBLs - producing E. coli isolates from minced meat and environmental swab samples at meat retailer shops of Jimma town, Southwest Ethiopia.

METHODOLOGY

A cross-sectional descriptive study was conducted from March to June, 2016. A total of 168 minced meat and swab samples were first enriched by buffered peptone water (BPW) for overnight and streaked onto MacConkey agar. Double disk synergy (DDS) method was used for detection of ESBL-producing strains. A disk of amoxicillin + clavulanic acid (20/10 μg) was placed in the center of Mueller-Hinton agar plate, and cefotaxime (30 μg) and ceftazidime (30 μg) were placed at a distance of 20 mm from the central disk. Checklist was used to assess hygienic status of butcher shops and practices meat handlers.

RESULTS

A total of 35 (20.80%) biochemically confirmed E. coli were obtained from 168 samples. Of these, 21 (23.9%) of them were detected from 88 minced meat and the other 14 (17.5%) from 80 swab samples taken from butcher's hand, knives, chopping board and protective clothing. From 35 E. coli isolates, 7(20%) of them were confirmed as ESBL- producers. Among ESBL- producing strains, 85.7% were resistant for cefotaxime and ceftriaxone and 71.4% for ceftazidime. Among non-ESBLs-producing strains only seven isolates were resistant to third generation cephalosporin. All E. coli isolates were resistant to ampicillin, penicillin and erythromycin, and susceptible to amikacin. Poor hygienic status of butcher shops and unhygienic practice of meat handlers were observed.

CONCLUSION

The detections of ESBLs- producing strains could be contributed for the increment of multi drug resistant isolates. This study also concluded that, unhygienic meat handling and processing practice can contribute for contaminations of meat. Thus, strategies should be planned and implemented to improve the knowledge and practice of butchers about handling and processing of meat.

Prevalence of extended-spectrum beta-lactamase producing bacteria from animal origin: A systematic review and meta-analysis report from India

Antimicrobial resistance (AMR) due to the emergence and spread of extended-spectrum beta-lactamase (ESBL) producing bacteria are becoming a serious global public health concern. This article aims to assess the overall prevalence of ESBLs among animals in India, with year-wise, zone-wise and species-wise stratification. Systematic search from PubMed, Google Scholar and J-Gate Plus was carried out and 24 eligible articles from 2013–2019 in India were retrieved. The R Open source Scripting software was used to perform statistical analysis. The overall prevalence of ESBLs among animals in India was 9%. The pooled prevalence of ESBLs in animals were 26, 11, 6 and 8% for north, east, south and central zones, respectively. The reported prevalence of ESBLs in animals were 12, 5, 8, 8, 12, 13 and 33% were reported for the years 2013, 2014, 2015, 2016, 2017, 2018, 2019 respectively. The species-wise stratified results showed a predominance of ESBL producing Klebsiella pneumoniae strains (11%) when compared to Escherichia coli and Pseudomonas spp. which were 7% and 5%, respectively. The prevalence data generated could be utilized in infection control and in antibiotic use management decisions for developing appropriate intervention strategies.

Proteomic analysis of ESBL-producing Escherichia coli under bentonite condition

The dissemination of extended spectrum beta-lactamases (ESBL) genes through gene transfer attracts wide attention. Bentonite is widely used as a feed additive in an animal-breeding environment. In order to obtain a better understanding of the effect of bentonite on Escherichia coli carrying ESBL gene, proteomic analysis was carried out to screen the key proteins. The results showed that a total of 31 proteins were differentially expressed, including 21 up-regulated proteins and 10 down-regulated proteins. These proteins were involved in biosynthetic process, metabolic process, stress response, transport, anaerobic respiration, proteolysis, hydrolase, protein folding, transcription, salvage, and other. The transcriptional level of four genes (mipA, gntY, tldD, and arcA) was in consensus with proteomic results. This study revealed the differentially expressed proteins involved when E. coli was incubated under bentonite and PBS condition, which implied the possibility that bentonite may promote the transfer of ESBL gene between E. coli.

Comparative Epidemiology and Resistance Trends of Proteae in Urinary Tract Infections of Inpatients and Outpatients: A 10-Year Retrospective Study

Compared with infections caused by other bacterial pathogens, urinary tract infections (UTIs) caused by Proteae are often more severe and associated with a higher rate of recurrence, sequelae, and pyelonephritis. The aim of this retrospective study was to assess and compare the prevalence of UTIs caused by different species of the Proteae tribe (namely Proteus, Morganella and Providencia species) and the antibiotic resistance levels isolated from inpatients and outpatients in a primary- and tertiary-care teaching hospital in the Southern Great Plain of Hungary, during a 10-year study period. To evaluate the resistance trends of isolated strains, amoxicillin/clavulanic acid, ceftriaxone, meropenem, ertapenem, gentamicin, ciprofloxacin, and fosfomycin were chosen as indicator antibiotics, based on local antibiotic utilization data. Members of Proteae were more frequently isolated in the case of inpatients (7.20 ± 1.74% vs. 5.00 ± 0.88%; p = 0.0031), P. mirabilis was the most frequently isolated member of the group. The ratio of resistant strains to sulfamethoxazole/trimethoprim, ciprofloxacin, ceftriaxone, and fosfomycin was significantly higher in the inpatient group. In the case of amoxicillin/clavulanic acid, ceftriaxone, ciprofloxacin, and sulfamethoxazole/trimethoprim, the ratio of resistant isolates was markedly higher between 2013–2017 (p < 0.01). Resistance developments of Proteae, coupled with their intrinsic non-susceptibility to several antibiotics (tetracyclines, colistin, nitrofurantoin) severely limits the number of therapeutic alternatives, especially for outpatients.

Comparative Epidemiology and Resistance Trends of Common Urinary Pathogens in a Tertiary-Care Hospital: A 10-Year Surveillance Study

Background and Objective: Urinary tract infections (UTIs) are common in human medicine, affecting large patient populations worldwide. The principal cause of UTIs is uropathogenic Escherichia coli (UPEC) and Klebsiella, both in community and nosocomial settings. The assessment of local data on prevalence and resistance is essential to evaluate trends over time and to reflect on the national situation, compared to international data, using the methods of analytical epidemiology. Materials and Methods: The aim of this study was to assess resistance trends and epidemiology of UTIs caused by E. coli and Klebsiella species in inpatients and outpatients at a tertiary-care hospital in Hungary, using microbiological data. To evaluate resistance trends, several antibiotics were chosen as indicator drugs, based on local utilization data. Results: E. coli was the most prevalent isolate, representing 56.75 ± 4.86% for outpatients and 42.29 ± 2.94% for inpatients. For E. coli, the ratio of resistant strains for several antibiotics was significantly higher in the inpatient group, while in Klebsiella, similar trends were only observed for gentamicin. Extended-spectrum β-lactamase (ESBL)-producing isolates were detected in 4.33-9.15% and 23.22-34.22% from outpatient, 8.85-38.97% and 10.89-36.06% from inpatient samples for E. coli and Klebsiella, respectively. Conclusions: Resistance developments in common UTI pathogens (especially to fosfomycin, sulfamethoxazole-trimethoprim, fluoroquinolones, and 3rd generation cephalosporins), seriously curb therapeutic options, especially in outpatient settings.

Teaching an Old Class New Tricks: A Novel Semi-Synthetic Aminoglycoside, Plazomicin

The emergence of multi-drug resistant (MDR) Gram-negative pathogens has become a serious worldwide health concern. Gram-negative bacteria such as Enterobacteriaceae (Klebsiella pneumoniae, Escherichia coli, Enterobacter spp.,) Acinetobacter spp., and Pseudomonas aeruginosa have rendered most antibiotics inactive, leaving aminoglycosides and polymyxins. Plazomicin (formerly ACHN-490), is a neoglycoside with unique structural modifications to the aminoglycoside pharmacophore that impart activity against many MDR Gram-negative organisms. ACHN-490 was recently approved by the US Food and Drug Administration for the treatment of complicated urinary tract infections caused by MDR Enterobacteriaceae. In this era of increasing Gram-negative resistance, it is imperative to critically evaluate new antibiotics so that we understand how to use them optimally. The objective of this article is to discuss available data detailing plazomicin's biochemistry, pharmacokinetic/pharmacodynamic characteristics, in-vitro activity and current progress in clinical trials. In addition, plazomicin's potential role in therapy for the treatment of MDR Gram-negative infections will be discussed.

Epidemiological Trends and Resistance Associated with Stenotrophomonas maltophilia Bacteremia: A 10-Year Retrospective Cohort Study in a Tertiary-Care Hospital in Hungary

Stenotrophomonas maltophilia has been recognized as an emerging nosocomial pathogen in invasive infections of immunocompromised, severely debilitated patients with significant underlying illnesses. The first-choice drug in these infections is sulfamethoxazole-trimethoprim (SMX/TMP), and resistance to this antimicrobial is a daunting challenge for clinicians. The aim of this study was to assess the prevalence of S. maltophilia bacteremia and SMX/TMP-resistance levels at a tertiary-care university hospital. A total of 175 episodes of S. maltophilia bacteremia were identified (2008-2012: n = 82, 2013-2017: n = 93; p = 0.061), 52% of affected patients were 60 years of age, and had recent surgery, severe injuries or underlying conditions (malignant hematologic diseases and solid tumors) in their history. Sixteen percent of isolates were resistant to SMX/TMP (2008-2012: n = 13.8%, 2013-2017: n = 17.2%; p = 0.076), and out of the resistant strains, 32.7% were also resistant to levofloxacin and colistin. Our findings on the SMX/TMP-resistance were similar to global literature data.

Multidrug resistance and risk factors associated with community-acquired urinary tract infections caused by Escherichia coli in Venezuela

INTRODUCTION

The treatment of urinary tract infections has become more challenging due to the increasing frequency of multidrug-resistant Escherichia coli in human populations.

OBJECTIVE

To characterize multidrug-resistant E. coli isolates causing community-acquired urinary tract infections in Cumaná, Venezuela, and associate possible risk factors for infection by extended-spectrum beta-lactamases (ESBL)-producing isolates.

MATERIALS AND METHODS

We included all the patients with urinary tract infections attending the urology outpatient consultation and emergency unit in the Hospital de Cumaná, Estado Sucre, Venezuela, from January through June, 2014. blaTEM, blaSHV and blaCTX-M genes detection was carried out by PCR.

RESULTS

We found a high prevalence of multidrug-resistant E. coli (25.2%) with 20.4% of the isolates producing ESBL. The ESBL-producing isolates showed a high frequency (66.7%) of simultaneous resistance to trimethoprim-sulphamethoxazole, fluoroquinolones and aminoglycosides compared to non-producing isolates (2.4%). Of the resistant isolates, 65.4% carried the blaTEM gene, 34.6% the blaCTX-M and 23.1% the blaSHV. The blaCTX-M genes detected belonged to the CTX-M-1 and CTX-M-2 groups. Plasmid transfer was demonstrated by in vitro conjugation in 17 of the 26 ESBL-producing isolates. All three genes detected were transferred to the transconjugants. Age over 60 years, complicated urinary tract infections and previous use of a catheter predisposed patients to infection by ESBL-producing E. coli.

CONCLUSIONS

The high frequency of multidrug-resistant ESBL-producing isolates should alert the regional health authorities to take measures to reduce the risk of outbreaks caused by these types of bacteria in the community.

The prevalence of resistant Gram-negative bacteraemia among hospitalized patients in Tucson, Arizona over a 12-month period; A retrospective single center study

Introduction

The objectives of this retrospective review were to: (a) determine the prevalence of resistant Gram-negative bacteraemia among hospitalized patients; (b) evaluate antibiotic use; (c) determine the time taken for Gram staining to final species identification.

Methods

For this retrospective study, information was extracted from patients’ electronic medical records. Eligible patients had been admitted to a 300-bed tertiary care hospital in Tucson, Arizona from October 2015 to October 2016, were over 18 years of age and had a positive blood culture for Gram-negative bacteraemia.

Results

In total, 84 patients with Gram-negative bacteraemia were identified; urinary tract infection was the most common source of infection (71%). ESBL-producing microorganisms were isolated from five (6%) patients and no MDR pathogens were identified. The, median time to Gram stain was 20.5 hours and the median time to final identification was 54.5 hours. Delayed de-escalation of broad-spectrum antibiotics (i.e., >24 hours after final culture) occurred in 25% patients with a median length of hospital stay of 118 hours (range: 56–552 hours) compared with a median length of hospital stay of 89 hours (range: 5–334 hours) in the early de-escalation group.

Conclusion

The prevalence of bacteraemia due to resistant Gram-negative microorganisms is low (6%) in this institution. However, there may be room for improvement in the antimicrobial stewardship program with regard to rapid diagnostic testing.

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.

Acquisition and dissemination of cephalosporin-resistant E. coli in migratory birds sampled at an Alaska landfill as inferred through genomic analysis

Antimicrobial resistance (AMR) in bacterial pathogens threatens global health, though the spread of AMR bacteria and AMR genes between humans, animals, and the environment is still largely unknown. Here, we investigated the role of wild birds in the epidemiology of AMR Escherichia coli. Using next-generation sequencing, we characterized cephalosporin-resistant E. coli cultured from sympatric gulls and bald eagles inhabiting a landfill habitat in Alaska to identify genetic determinants conferring AMR, explore potential transmission pathways of AMR bacteria and genes at this site, and investigate how their genetic diversity compares to isolates reported in other taxa. We found genetically diverse E. coli isolates with sequence types previously associated with human infections and resistance genes of clinical importance, including bla_CTX-M and bla_CMY. Identical resistance profiles were observed in genetically unrelated E. coli isolates from both gulls and bald eagles. Conversely, isolates with indistinguishable core-genomes were found to have different resistance profiles. Our findings support complex epidemiological interactions including bacterial strain sharing between gulls and bald eagles and horizontal gene transfer among E. coli harboured by birds. Results suggest that landfills may serve as a source for AMR acquisition and/or maintenance, including bacterial sequence types and AMR genes relevant to human health.

CTX-M-15 is Established in Most Multidrug-Resistant Uropathogenic Enterobacteriaceae and Pseudomonaceae from Hospitals in Nigeria

β-Lactam antibiotics are widely used to treat urinary tract infections in Nigeria. This study aimed to determine the presence and characteristics of extended spectrum β-lactamases in commonly isolated uropathogenic Gram-negative bacteria (GNB) in Nigeria. Fifty non-duplicate GNB isolates consisting of Escherichia coli, 19; Klebsiella pneumoniae, 21; and Pseudomonas aeruginosa, 10 were obtained from three tertiary hospitals in Nigeria. The antibiotic susceptibility testing of all isolates to a panel of antibiotics including minimum inhibitory concentrations (MICs) and extended spectrum β-lactamases was determined. Polymerase chain reactions and sequencing were used to detect β-lactam genes. Polymerase chain reactions and sequencing identified varying extended spectrum β-lactamases (ESBLs) encoding genes for 24 isolates (48.0%). Cefotaximase-Munich (CTX-M) 15 was the dominant gene with 20/24 of the isolates positive at 83.3%; multiple genes (2 to 6 ESBL genes) were found in 20 of the isolates. The isolates encoded other genes such as CTX-M-14, 33.3%; sulfhydryl variable (SHV) variants, 58.3%; oxacillinase (OXA) variants, 70.8%; OXA-10, 29.2%; and Vietnamese extended β-lactamase (VEB) 1, 25.0%. There was no difference between the MIC₅₀ and MIC₉₀ of all the isolates. The high-level multidrug resistance of uropathogens to third generation cephalosporins including other antibiotics used in this study is strongly associated with carriage of ESBLs, predominantly CTX-M-15, as well as CTX-X-M-14, OXA-10, and VEB-1.

Epidemiology and susceptibility of pathogens from SMART 2011-12 Turkey: evaluation of hospital-acquired versus community-acquired urinary tract infections and ICU- versus non-ICU-associated intra-abdominal infections

Objectives

To describe the epidemiology and susceptibility of pathogens (including ESBL producers) from hospital-acquired (HA) versus community-acquired (CA) urinary tract infections (UTIs) and ICU- versus non-ICU-associated intra-abdominal infections (IAIs) in Turkey as a part of the SMART study.

Methods

: For this report, Gram-negative pathogens (363 from UTIs and 458 from IAIs) were collected in 2011 and 2012 at six hospitals in Turkey. HA versus CA UTIs and ICU- versus non-ICU-associated IAIs were compared for the species isolated, percentage of ESBL-positive isolates by species and susceptibility for overall and individual Gram-negative species.

Results

: Escherichia coli was the most common pathogen identified in HA (40.2%) and CA (73.9%) UTIs and ICU-associated (25.8%) and non-ICU-associated (43.3%) IAIs. The rate of ESBL-positive E. coli was significantly higher in HA than in CA UTIs (50.5% versus 38.2%, P  <   0.001) and in non-ICU-associated than in ICU-associated IAIs (52.5% versus 29.2%, P  = 0.029). Of the drugs studied, only amikacin was active against ≥90% of pathogens in UTIs, while ertapenem, imipenem and amikacin were active against ≥90% of E. coli ; and imipenem, amikacin and cefoxitin were active against ≥90% of Klebsiella pneumoniae in IAIs.

Conclusions

Our findings demonstrated that E. coli continues to be the principal pathogen of UTIs and IAIs in Turkey. Along with a high rate of ESBL-positive isolates, high antimicrobial resistance among Gram-negative bacilli from either UTIs or IAIs was noted particularly in the case of HA UTIs and ICU-associated IAIs, with a higher likelihood of carbapenem- or amikacin-based therapy to provide the broadest activity against bacterial pathogens.

Deriving a management algorithm for emphysematous pyelonephritis: Can we rely on minimally invasive strategies or should we be opting for earlier nephrectomy?

PURPOSE

To analyse the incidence and management of emphysematous pyelonephritis (EPN) in North West London and examine factors that influence immediate and 6-month outcomes with the aim of guiding future management.

METHODS

This work analyses EPN cases from the London North West Healthcare NHS Trust from October 2006 to July 2015 (population ≈ 850,000). Diagnosis and stage were confirmed by computed tomography (CT). Demographic, clinical, biochemical and microbiological characteristics were assessed. Treatment modalities were medical management, minimally invasive management (MIM) and surgical. Immediate and 6-month outcomes were analysed.

RESULTS

Thirteen cases were identified (f = 8, m = 5) from 5525 CT scans. EPN occurred in patients with diabetes mellitus (n = 11, 84.6%), hypertension (n = 10, 76.9%) or urinary tract calculi (n = 7, 53.85%). Unilateral EPN occurred predominantly (n = 11, 84.6%); 46.1% (n = 6) were class 1 or 2 and 53.8% (n = 7) class 3 or 4. Escherichia coli was most commonly cultured (n = 5, 38.46%). All patients received antibiotics, and ten cases required MIM. Two patients had a delayed nephrectomy, both survived. Mortality was 15.4% (n = 2, grade 1 and 3a), both died acutely post-MIM, neither underwent emergency nephrectomy. At 6 months, eight patients had ongoing renal impairment. No specific poor prognostic factors were identifiable.

CONCLUSIONS

Patients with low-grade EPN may also have a high mortality rate. In the two cases who died, earlier consideration for nephrectomy may have been prudent. It may be beneficial to have a low threshold for prompt emergency nephrectomy in severe cases and where MIM treatment has failed. We suggest a management algorithm to guide clinicians and minimise mortality.