Antimicrobial Resistance In Enterobacteriaceae Research Articles

Antimicrobial resistance of Enterobacteriaceae and Staphylococcus spp. isolated from raw cow's milk from healthy, clinical and subclinical mastitis udders

Mastitis is the most common disease of dairy cattle and can be manifested in clinical and subclinical forms. The overuse of antimicrobials in the treatment and prevention of mastitis favours antimicrobial resistance and milk can be a potential route of dissemination. This study aimed to evaluate the biological quality of bulk tank milk (BTM) and the microbiological quality and signs of mastitis of freshly milked raw milk. In addition, to evaluate antimicrobial resistance in Enterobacteriaceae and Staphylococcus spp. isolated from freshly milked raw milk. None of the farms were within the official Brazilian biological quality limits for BTM. Freshly milked raw milk with signs of clinical (CMM), subclinical (SCMM) and no signs (MFM) of mastitis were detected in 6.67%, 27.62% and 65.71% samples, respectively. Most samples of freshly milked raw milk showed acceptable microbiological quality, when evaluating the indicators total coliforms (78.10%), Escherichia coli (88.57%) and Staphylococcus aureus (100%). Klebsiella oxytoca and S. aureus were the most prevalent microorganisms in SCMM and MFM samples. Antimicrobial resistance and multidrug resistance (MDR) were observed in 65.12% and 13.95% of Enterobacteriaceae and 84.31% and 5.88% of Staphylococcus spp., respectively, isolated from both SCMM and MFM samples. Enterobacteriaceae resistant to third-generation cephalosporin (3GCR) (6.98%) and carbapenems (CRE) (6.98%) and methicillin-resistant S. aureus (MRSA) (4.88%) were observed. Antimicrobial-resistant bacteria can spread resistance genes to previously susceptible bacteria. This is a problem that affects animal, human and environmental health and should be evaluated within the one-health concept.

Prevalence of drug resistant Enterobacteriaceae in a Nepalese tertiary care hospital.

Antimicrobial resistance in Enterobacteriaceae is an emerging global public health problem. Numerous studies have reported community-acquired AmpC beta-lactamase and extended spectrum beta-lactamase (ESBL) producing Enterobacteriaceae in Nepal. However, there are limited data on community-acquired Metallo-beta-lactamase (MBL) producing Enterobacteriaceae. A hospital-based descriptive cross-sectional study was conducted using 294 Enterobacteriaceae isolates from a total of 2,345 different clinical specimens collected from patients attending a tertiary care hospital in Nepal. Bacteria were isolated using standard microbiological growth media and identified using biochemical tests. For antimicrobial susceptibility testing, Kirby-Bauer disc diffusion technique was used. AmpC, ESBL, and MBL productions were detected by using combined disc method. AmpC, ESBL, and MBL productions were detected in 19.4%, 29.6%, and 8.5% of total Enterobacteriaceae isolates respectively. Higher rates of beta-lactamases production were seen among the isolates from in-patients in comparison with those from out-patients. However, 11.6%, 25%, and 3.7% of the total isolates from out-patients were AmpC, ESBL, and MBL producers respectively. The co-production of the beta-lactamases was also detected, with two Klebsiella pneumoniae isolates producing all three beta-lactamases. One MBL producing Proteus vulgaris isolate that was pan-resistant with no remaining treatment options was also isolated. Prevalence of drug resistant Enterobacteriaceae in our study was very high. Detection of AmpC, ESBL, and MBL positive isolates from out-patients, who did not have recent history of hospital visit, indicated the community dissemination of the drug resistant bacteria. This is a matter of great concern and an immediate attention to formulate strategies to prevent further development and spread of antibiotic resistance is required.

Prevalence and antimicrobial resistance of Enterobacteriaceae in the north of Kazakhstan.

An increasing number of drugs are used each year in the treatment of small pets (cats and dogs), including medicines (cephalosporins and fluoroquinolones) used in human therapy. The purpose of this study was to isolate and explore the antibiotic resistance of opportunistic Enterobacteriaceae (Escherichia coli, Klebsiella, Proteus, Ci trobacter, Enterobacter) from cats and dogs, and to isolate resistance genes in the microorganisms. In 2021, 808 samples of biological material from small domestic animals were collected in veterinary clinics in Kostanay. From these, 210 microorganisms were isolated and identified. A large majority of the strains sampled belonged to E. coli-149 (70.9%), Enterobacter-11 (5.2%), Klebsiella-28 (13.3%), Proteus-12 (5.7%) and 10 Citrobacter isolates (4.8%). In all isolates identified, antibiotic resistance/sensitivity was determined by disc-diffusion method to ampicillin, cefoxitin, gentamicin, levomycetin, tetracycline, ciprofloxacin, norfloxacin, ofloxacin, cefoperazone, cefpodoxime, streptomycin, kanamycin, doxycycline, gemifloxacin, nalidixic acid, furazolidone, furadonine, amoxicillin, and enrofloxacin. The study has demonstrated that the greatest number of Enterobacteriaceae were sensitive to the action of meropenem, which belongs to the group of beta-lactam antibiotics; resistance was demonstrated against tetracycline, doxycycline, ampicillin, amoxicillin, ofloxacin, and cefpodoxime. The most common genes encoding antimicrobial resistance were as follows: BlaTEM and OXA in 41 and 28 isolates, respectively, encoding resistance to beta-lactams; StrA and StrB in 45 and 48 isolates encoding aminoglycosides; and tetA and tetB in 43 and 28 isolates encoding tetracyclines. Obtained data demonstrate that uncontrolled and frequent use of beta-lactam and tetracycline antibacterials, in cats and dogs, results in the spread of genotypic resistance among micro-organisms of the family Enterobacteriaceae.

Correspondence to Hasegawa et al. "Diagnostic Accuracy of Hospital Antibiograms in Predicting the Risk of Antimicrobial Resistance in Enterobacteriaceae Isolates: A Nationwide Multicenter Evaluation at the Veterans Health Administration".

Correspondence to Hasegawa et al. "Diagnostic Accuracy of Hospital Antibiograms in Predicting the Risk of Antimicrobial Resistance in Enterobacteriaceae Isolates: A Nationwide Multicenter Evaluation at the Veterans Health Administration".

Occurrence and characteristics of extended-spectrum-β-lactamase producing Escherichia coli (blaTEM-128) isolated from Mus musculus captured from a veterinary clinic and houses in Tunis, Tunisia

Antimicrobial resistance in Enterobacteriaceae is a public health problem. Rodents, can be a potential vector for transmission of multidrug resistant bacteria between animals, humans, and environment. The aim of our study was to assess the level of Enterobacteriaceae present in the intestines of rats collected from different locations in Tunisia, then to determine their antimicrobial susceptibility profiles, to screen extended spectrum β-lactamases-producing strains and determine the molecular mechanism of β-lactams resistance.Between July 2017 and June 2018, 55 strains of Enterobacteriaceae were isolated from 71 rats captured in various locations in Tunisia. Antibiotic susceptibility testing was performed using the disc diffusion method. Genes encoding ESBL and mcr genes were investigated by RT-PCR, standard PCR and sequencing when these genes were found.Fifty-five strains of Enterobacteriaceae were identified. The overall prevalence of ESBL production found in our study was 12.7 % (7/55) of which two E. coli strains were DDST positive, one isolated from a house-caught rat and one from the veterinary clinic and harbored the blaTEM-128 gene. In addition, the other five strains were DDST negative and harbored the blaTEM gene, including three strains isolated from collective restaurant (n = 2: blaTEM-163; n = 1: blaTEM-1), one strain isolated from the veterinary clinic (blaTEM-82), and one strain isolated from a house (blaTEM-128).The results of our study suggest that rodents may play a role in the spread of antimicrobial resistant E. coli, highlighting the need to protect the environment and monitor antimicrobial resistant bacteria in rodents to prevent their spread to other wildlife and humans.

Incidence of Drug-Resistant Enterobacteriaceae Strains in Organic and Conventional Watermelons Grown in Tennessee.

The production and consumption of organic fresh produce have constantly increased since the 1990s. Consumers prefer organic produce because it does not contain synthetic chemical residues that are often implicated in health problems. The contamination of fresh produce by pathogenic Enterobacteriaceae strains remains a major challenge, and is responsible for frequent foodborne disease outbreaks. The use of antibiotics has proved an effective treatment, but the increase in occurrences of antibiotic resistance is becoming a health challenge. This study seeks to establish the presence of antimicrobial resistance in Enterobacteriaceae on organic and conventional watermelon fruits. Watermelons used for this study were cultivated at the Tennessee State University Certified Organic Farm, Nashville. At harvest, nine fruits were selected from among fruits lying on plastic mulch, and nine from fruits lying on the soil of both organic and conventional plots. These were placed in sterile sample bags for microbial analysis. Spread plating technique, API 20E, and apiweb software were used for microbial isolation and identification. Identified strains were tested for antimicrobial resistance against 12 common antibiotics. Seventeen Enterobacteriaceae strains were isolated and identified. Isolates were susceptible to gentamycin, ciprofloxacin, and chloramphenicol, but were resistant to cefoxitin. Citrobacter freundii showed a 14.3% resistance to Streptomycin. Pantoea spp. and Providencia rettigeri showed 50% and 100% resistance to tetracycline. Findings from this study confirm the presence of antibiotic-resistant Enterobacteriaceae strains on organic watermelons in Nashville, TN.

Antimicrobial Resistance of Enterobacteriaceae in Bloodstream Infections in Hospitalized Patients in Southern Poland

Aim: The aim of this study was to highlight antimicrobial resistance among Enterobacteriaceae isolated from bloodstream infections in hospitals in southern Poland. Materials and Methods: The present study includes laboratory-confirmed secondary bloodstream infections (LC-BSIs), in the years 2015–2018, in hospitalized adult patients (≥18). Episodes of BSIs were defined according to the strictly described guidelines. Antimicrobial susceptibility testing was performed with the automated system and the disc diffusion method. Extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriaceae were detected using the double-disc synergy test. Results: Between 2015 and 2018, 356 episodes of secondary BSIs in 997 patients aged 21–96 years were documented in a prospective study, including 134 (37.6%) ESBL-producing Enterobacteriaceae. Escherichia coli was the predominant pathogen in internal medicine (37.6%) and surgery units (46.8%); in intensive care units (ICUs), Klebsiella pneumoniae was isolated more frequently (33.3%). Enterobacteriaceae were highly resistant to most antimicrobial agents. K. pneumoniae isolates had a higher level of resistance than E. coli, regardless of the unit. Conclusions: The increase in AMR and the widespread distribution of ESBL-producing Enterobacteriaceae in Polish hospitals can be related to the lack of or inappropriate antibiotic treatment.

Prevalence of antibiotic resistance in Enterobacteriaceae among the patients hospitalized in Al-Zahra hospital, Isfahan, Iran

Introduction: Enterobacteriaceae are a high prevalent gram-negative species worldwide, which play a major role in various infections. Objectives: The present study aims to assess the prevalence of antimicrobial resistance in Enterobacteriaceae at a tertiary hospital in Isfahan, Iran. Materials and Methods: This cross-sectional laboratory-based study was performed during 2020 in Al-Zahra hospital, Isfahan, Iran. The isolates of all of the clinical samples submitted for the bacterial culture containing Enterobacteriaceae strains were checked for antibiotic resistance during March 2018 to March 2019. Results: The results revealed that the specimens obtained from intensive care units (ICUs) exhibited more resistance than the others. Additionally, the highest abundant antibiotic resistance among inpatients was related to ampicillin/sulbactam, and carbapenem resistance was significantly high. Conclusion: The high prevalence of antibiotic resistance indicated the inappropriate antibiotic prescription in this center. The results emphasized the importance of preventive strategies and restrictions in over-the-counter antibiotic consumption.

Integrons as emerging contaminants facilitating the widespread of antimicrobial resistance in Enterobacteriaceae

Integrons as emerging contaminants facilitating the widespread of antimicrobial resistance in Enterobacteriaceae

Draft genome sequence of colistin-resistant and extended-spectrum β-lactamase (ESBL)-producing multidrug-resistant Escherichia coli isolated from poultry meat

The presence of multidrug-resistant bacteria in the food chain represents a major public-health concern and has significant economic repercussions. Here we describe the draft genome sequence of serotype O21:H16, multilocus sequence typing (MLST) ST3270 and ribosomal MLST rST120701, multidrug-resistant Escherichia coli Ch7_4SIAU, which was isolated from poultry meat collected from a local market in Jeddah, Saudi Arabia. Ch7_4SIAU was grown on MacConkey agar and was identified using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). An Illumina MiSeq platform was used to generate 2.4 million paired-end reads of 150 bp. The draft genome of Ch7_4SIAU is ∼5.1 Mb with a GC content of ∼50% and contains five plasmid replicons [ColpVC, IncFII, IncHI2, IncI(Gamma) and IncX1]. The isolate is resistant to third- and fourth-generation cephalosporins. It carries the mobile colistin resistance gene mcr-1.1 and the extended-spectrum β-lactamase (ESBL) gene blaCTXM-15 as well as the astA gene encoding enteroaggregative E. coli heat-stable enterotoxin 1 (EAST-1). This report presents the first draft genome of ESBL-positive E. coli isolated from poultry meat in Saudi Arabia. The findings can be used as a reference for genomic epidemiological studies of antimicrobial resistance in Enterobacteriaceae in the local food chain.

Antimicrobial resistance in Enterobacteriaceae isolated from arthropods in Gifu City, Japan.

The wide occurrence of antimicrobial-resistant (AMR) bacteria in various environments is of great concern. Here, we examined the prevalence and antimicrobial susceptibility of Enterobacteriaceae isolated from 88 wild arthropods, collected in Gifu city, Japan. In total, 168 isolates of Enterobacteriaceae were obtained from 61 arthropods. All isolates were susceptible to all the antimicrobial agents tested, except colistin (31 isolates) and kanamycin (one isolate). The aph(3')-Ia gene, responsible for kanamycin resistance, was detected in Klebsiella oxytoca. Although synanthropic arthropods (houseflies and cockroaches) serve as vectors for AMR Enterobacteriaceae, other wild arthropods are not crucial carriers of Enterobacteriaceae resistant to antimicrobial agents.

Genetic Features of blandm-1 and Characterization of the Corresponding Knockout Mutant of Enterobacter cloacae Produced by Red Homologous Recombination

Background: New Delhi metallo-beta-lactamase 1 (NDM-1) is considered to be an important factor of antimicrobial resistance in Enterobacteriaceae. In China, the blaNDM-1 gene has been mostly detected in carbapenem-resistant Acinetobacter spp. but is less reported in Enterobacteriaceae and more rarely found in E. cloacae. Objectives: This study explored the genetic features of the blaNDM-1 gene of E. cloacae and a blaNDM-1knockout mutant was constructed using Red homologous recombination. In addition, the effect of the knockout on antimicrobial resistance, growth ability, and in vitro competitiveness was investigated. Methods: The upstream and downstream structures of the blaNDM-1 gene were analyzed in ten E. cloacae isolates using primer walking and PCR mapping. A blaNDM-1 knockout mutant was constructed through Red homologous recombination and verified by PCR, RT-qPCR, and sequencing. The antimicrobial susceptibility, growth curves, and in vitro growth competitiveness were compared between the blaNDM-1 knockout mutant and the parental strain. Results: All E. cloacae study isolates except for strain T10, contained an identical blaNDM-1 gene structure. The ΔISAba125 truncated by ISEc33 element and the bleo followed by a ΔtrpF and ISSen4 was located immediately upstream and downstream of T1-T9 strains. However, the ΔISAba125 and the bleo followed by a ΔtrpF were located immediately upstream and downstream, respectively, in the T10 strain. PCR, RT-qPCR, and DNA sequencing analyses showed that the blaNDM-1 knockout mutant was successfully constructed. The blaNDM-1 knockout mutant and the parental strain exhibited similar resistance patterns to penicillin, cephalosporins, aminoglycosides, tetracycline, and quinolones. Both strains displayed similar growth curves in Luria Broth. The competition index (CI), defined as the knockout mutant/parental strain ratio was 0.69 in the competition experiment in vitro. Conclusions: The DNA regions upstream and downstream of the blaNDM-1 gene often contained insertion sequences and elements. Red homologous recombination was successfully used to knock out blaNDM-1 in E. cloacae, which allowed us to decipher the links between this gene, antimicrobial resistance, and bacterial growth competitiveness.

A survey of antimicrobial resistance in Enterobacteriaceae isolated from the Chesapeake Bay and adjacent upper tributaries.

In recent years, the rise in antimicrobial resistance (AR) in the healthcare setting as well as the environment has been recognized as a growing public health problem. The Chesapeake Bay (CB) and its upper tributaries (UT) is a large and biologically diverse estuary. This pilot study evaluated the presence of AR of gram‐negative bacteria isolated from water samples collected at various sites of the Chesapeake Bay. Bacterial organisms were identified and antimicrobial susceptibility testing was performed by phenotypic and genotypic methods. Ninety‐two distinctly different gram‐negative bacteria were identified; Klebsiella pneumoniae, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, and Escherichia coli were most often isolated. Serratia marcescens was more frequently isolated in samples from the UT compared to the CB. Antimicrobial resistance was more frequently detected in organisms from the CB by phenotypic and genotypic methods. Antimicrobial resistance to ampicillin, imipenem, tetracycline, and chloramphenicol were the most frequently observed resistance patterns. ACT‐1, CMY, and SHV genes were the most frequently detected resistance genes, with predominance in organism isolated from the CB. The results from this study emphasize the importance for further developing comprehensive surveillance programs of AR in bacterial isolates in the various environments, such as recreational and other water systems.

Antimicrobial Resistance in ESBL-Producing Escherichia coli Isolated from Layer and Pig Farms in Thailand

Background: Study of drug resistance of commensal bacteria in both humans and animals can determine the scale of the drug resistance problem. Usage of antimicrobials to treat infections in humans and animals has generated extensive antimicrobial pressure not only on targeted pathogens but also on commensal bacteria. Commensal Escherichia coli appears to be the major reservoir for resistant genes implicated in the transmission of genetic traits from one bacterium to another. Antimicrobial resistance in Enterobacteriaceae has increased dramatically worldwide in the last decade. An increasing number of community-onset extended-spectrum beta-lactamase (ESBL)-producing bacterial infections, especially those caused by ESBL-producing E. coli, have been reported in many countries, including Thailand. Moreover, ESBL-producing E. coli have been widely detected in food-producing animals and the environment. The increased use of ESBLs in food animals is a serious public health problem. The objective of the study was to determine the prevalence and antimicrobial resistance pattern of ESBL-producing E. coli isolated from pigs, layers, farm workers and stagnant water, in order to increase awareness about antimicrobial usage on farms and to minimize the expansion of the antimicrobial resistance phenomenon in farm settings.Materials, Methods & Results: A total of 588 samples were collected from 107 pig farms and 89 layer farms in Chiang Mai–Lamphun and Chon Buri provinces during May 2015-April 2016. Double-disk diffusion method according to EUCAST (European Committee on Antimicrobial Susceptibility Testing) guidelines was used for detection. The results demonstrated that 36.7% (216/588) of samples were ESBL-producing E. coli-positive, including rectal swabs 74.8% (80/107), pig farm worker stool swabs 57.0% (61/107), stagnant water on pig farms 21.5% (23/107), healthy layer rectal swabs 6.7% (6/89) and layer farm worker stool swabs 51.7% (46/89). Most of the isolates were resistant against ampicillin (99.5%), followed by erythromycin (98.6%) and ceftriaxone (96.3%). All of them were classified as multidrug-resistant strains. Moreover, AMP-CRO-E-TE-C-SXT-CN was the most frequent phenotype pattern detected in animals, humans and the environment, followed by AMP-CRO-E-TE-C-SXT-NA-CN.Discussion: The present study offers clear evidence that the prevalence of ESBL-producing E. coli in healthy pigs is higher than in layers. One possible explanation is that a large amount and variety of antimicrobials are used on pig farms, resulting in a common and significant source of drug-resistant ESBL-producing E. coli. The lower incidence of ESBL-producing E. coli in samples from a pig farm environment than in samples of animal origin indicate that pigs are a reservoir of a reservoir for resistant bacteria and a source of environmental contamination. Antimicrobial resistance patterns of ESBLproducing E. coli detected in all sample types and study locations were quite similar. In almost all ESBL-producing E. coli isolates, resistance was shown against ampicillin, erythromycin, ceftriaxone, tetracycline and chloramphenicol. Moreover, multidrug resistance was found in all isolates of ESBL-producing E. coli. The differences in antimicrobial agent resistance patterns can be used to differentiate sources by employing analytical tools such as discriminant function analysis. A molecular typing protocol is recommended for use in a discriminant function analysis for pattern determination of pathogen spreading. However, genetic fingerprinting techniques for microbial source tracking are more expensive, and facilities with appropriate equipment and expertise are required.

Stress responses, outer membrane permeability control and antimicrobial resistance in Enterobacteriaceae.

Bacteria have evolved several strategies to survive a myriad of harmful conditions in the environment and in hosts. In Gram-negative bacteria, responses to nutrient limitation, oxidative or nitrosative stress, envelope stress, exposure to antimicrobials and other growth-limiting stresses have been linked to the development of antimicrobial resistance. This results from the activation of protective changes to cell physiology (decreased outer membrane permeability), resistance transporters (drug efflux pumps), resistant lifestyles (biofilms, persistence) and/or resistance mutations (target mutations, production of antibiotic modification/degradation enzymes). In targeting and interfering with essential physiological mechanisms, antimicrobials themselves are considered as stresses to which protective responses have also evolved. In this review, we focus on envelope stress responses that affect the expression of outer membrane porins and their impact on antimicrobial resistance. We also discuss evidences that indicate the role of antimicrobials as signaling molecules in activating envelope stress responses.

Prevalence and Antimicrobial Resistance of Enterobacteriaceae in Shell Eggs from Small-Scale Poultry Farms and Farmers' Markets

Public health concerns over the emergence of antimicrobial resistant bacteria have increased recently. The purpose of this study was to investigate the prevalence of antimicrobial resistant Enterobacteriaceae in shell eggs purchased from small poultry farms and farmers' markets. A total of 504 eggs were pooled to make 252 composite samples, consisting of 2 eggs per composite. The microbial quality of shell eggs was determined by standard quantitative, biochemical, and PCR techniques. Susceptibility to 13 antimicrobial agents was determined by the Kirby-Bauer disk diffusion technique, and results were interpreted based on Clinical and Laboratory Standards Institute values. Shell eggs and egg contents were positive for Escherichia coli (11.9 and 5.2%, respectively), Enterobacter (9.1 and 7.9%), and Serratia (11.5 and 4.8%). Salmonella was isolated from 3.6% of egg shells but not from egg contents. Mean (±SD) Enterobacteriaceae levels (4.4 ± 2.0 log CFU per eggshell) on shell eggs from poultry farms was significantly higher (P ≤ 0.05) than that on shell eggs from farmers' markets (2.1 ± 1.3 log CFU per eggshell). Of the 134 isolates recovered, resistance among isolates from farm and market shell eggs to erythromycin was most common (48.5 and 32.8%, respectively) followed by ampicillin (44.8 and 17.2%), and tetracycline (29.9 and 17.2%). The multiple antibiotic resistance index value for E. coli and Pantoea was 0.62, and that for Salmonella and Klebsiella terrigena was 0.08, indicating that Enterobacteriaceae in shell eggs can be resistant to multiple antimicrobial agents. These data reveal that shell eggs from small poultry farms and farmers' markets can harbor antimicrobial resistant pathogenic and commensal bacteria. Thus, failure to properly handle shell eggs poses a potential health hazard to consumers.

Infections due to Escherichia coli and Other Enteric Gram-Negative Bacilli

This review describes infections caused by Escherichia coli and related members of the family Enterobacteriaceae, excluding other genera that principally cause enteric infections. Infections caused by Salmonella, Shigella, and Yersinia are described in the review “Gastrointestinal Tract Infections," found elsewhere in this publication. The purpose of this review is to examine the specific epidemiology, clinical manifestations, and treatment of individual members of the Enterobacteriaceae. The emerging concern of antimicrobial resistance amongst enteric gram-negative organisms and the approach to treatment in the setting of infection with these resistant organisms are discussed in the review “Antimicrobial Resistance in Enteric Gram-Negative Organisms,” found elsewhere in this publication. Figures illustrate the mechanisms of antimicrobial resistance in Enterobacteriaceae. A table lists the clinical, epidemiologic, pathogenetic, and therapeutic aspects of infection with various pathotypes of Escherichia coli. This review contains 6 highly rendered figures, 1 table, and 79 references.

Antimicrobial resistance in Enterobacteriaceae in Brazil: focus on β-lactams and polymyxins.

During the last 30 years there has been a dissemination of plasmid-mediated β-lactamases in Enterobacteriaceae in Brazil. Extended spectrum β-lactamases (ESBL) are widely disseminated in the hospital setting and are detected in a lower frequency in the community setting. Cefotaximases are the most frequently detected ESBL type and Klebsiella pneumoniae is the predominant species among ESBL producers. Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae became widely disseminated in Brazil during the last decade and KPC production is currently the most frequent resistance mechanism (96.2%) in carbapenem resistant K. pneumoniae. To date KPC-2 is the only variant reported in Brazil. Polymyxin B resistance in KPC-2-producing K. pneumoniae has come to an alarming rate of 27.1% in 2015 in São Paulo, the largest city in Brazil. New Delhi metallo-β-lactamase was detected in Brazil in 2013, has been reported in different Brazilian states but are not widely disseminated. Antimicrobial resistance in Enterobacteriaceae in Brazil is a very serious problem that needs urgent actions which includes both more strict adherence to infection control measures and more judicious use of antimicrobials.

Evaluation of Antimicrobial Resistance in Enterobacteriaceae and Coliforms Isolated on Farm, Packaged and Loose Vegetables in Kentucky

Fresh produce normally carry epiphytic microorganisms; however, it can be contaminated with pathogenic bacteria. Categorized as ‘ready-to-eat’, most vegetables are consumed raw, thus, may present a food safety risk. Over the last three decades, global consumption of fresh vegetables has increased considerably, and the market has expanded by more than 20%. Concomitantly, the number of outbreaks involving fresh vegetables has increased significantly. Enterobacteriaceae members are involved in most of the bacterial outbreaks linked to fresh produce. There is a worldwide concern about the increased use of antimicrobials in agriculture. Antimicrobial resistant bacteria enter the food chain from the farm, often due to the use of animal manure. In the current study, the presence of entero-coliform bacteria and their antimicrobial susceptibilities in fresh vegetables sampled from small farms to retail was evaluated. Samples of vegetables were (i) collected directly from small farms from central Kentucky (n=59) and (ii) from four supermarkets in Frankfort, KY including loose and pre-packaged produce (n=72), analyzed for isolation of entero-coliform species. Members of the Enterobacteriaceae were detected on 25% of farm and 40% of retail produce, respectively. Approximately, 61% of the packaged produce and 19.4% of the loose produce had entero-bacterial presence, respectively. Their resistance to fourteen common antimicrobials was tested using Kirby-Bauer method. Approximately, 63% of isolates from farm and 70% of isolates from retail produce displayed resistance to at least three antimicrobial agents, while 18% of the isolates from farm and 41% from retail samples displayed resistance to at least ten antimicrobial agents. We conclude that ‘ready-to-eat’ fresh vegetables can be a source of exposure to pathogens with multiple drug resistance (MDR), defined as resistance to at-least three antimicrobial agents, leading to greater risks in immunocompromised individuals, and may serve as reservoirs for resistance gene transfers in human colon.

Trends in susceptibility of Escherichia coli from intra-abdominal infections to ertapenem and comparators in the United States according to data from the SMART program, 2009 to 2013.

Antimicrobial resistance in Enterobacteriaceae, including resistance to carbapenems, is increasing worldwide. However, using U.S. Study for Monitoring Antimicrobial Resistance Trends (SMART) data for 2009 to 2013, no statistically significant decreasing susceptibility trends were found overall for Escherichia coli isolates from patients with intra-abdominal infections. In the subset of isolates from community-associated infections, susceptibility to levofloxacin decreased significantly and the increasing rate of multidrug-resistant E. coli approached statistical significance. In 2013, ertapenem, imipenem, and amikacin showed the highest susceptibility rates (≥99%) and fluoroquinolones the lowest (<70%). The 10 non-ertapenem-susceptible isolates (0.3% of all E. coli isolates) encoded one or more carbapenemases, extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases, or non-ESBL β-lactamases.