Research

Jump to: Review

356 KiB

Open AccessArticle

Interference in Pheromone-Responsive Conjugation of a High-Level Bacitracin Resistant Enterococcus faecalis Plasmid of Poultry Origin

by Cindy-Love Tremblay and Marie Archambault

Int. J. Environ. Res. Public Health 2013, 10(9), 4245-4260; https://doi.org/10.3390/ijerph10094245 - 11 Sep 2013

Cited by 3 | Viewed by 6511

Abstract

The current study reports on contact interference of a high-level bacitracin- resistant pheromone-responsive plasmid of Enterococcus faecalis strain 543 of poultry origin during conjugative transfer of bcr antimicrobial resistance genes using a polyclonal antiserum aggregation substance_44–560 (AS). After induction with pheromones produced [...] Read more.

The current study reports on contact interference of a high-level bacitracin- resistant pheromone-responsive plasmid of Enterococcus faecalis strain 543 of poultry origin during conjugative transfer of bcr antimicrobial resistance genes using a polyclonal antiserum aggregation substance_44–560 (AS). After induction with pheromones produced by the recipient strain E. faecalis JH2-2, clumping of the donor E. faecalis strain 543 was observed as well as high transfer frequencies of bcr in short time broth mating. Filter mating assays from donor strain E. faecalis 543 to the recipient strain E. faecalis JH2-2 revealed conjugative transfer of asa1 (AS), bcrRAB and traB (negative regulator pheromone response) genes. The presence of these genes in transconjugants was confirmed by antimicrobial susceptibility testing, PCR, Southern hybridization and sequencing. A significant reduction in formation of aggregates was observed when the polyclonal anti-AS_44–560 was added in the pheromone-responsive conjugation experiments as compared to the induced state. Moreover, interference of anti-AS_44–560 antibodies in pheromone-responsive conjugation was demonstrated by a reduction in horizontal transfer of asa1 and bcr genes between E. faecalis strain 543 and E. faecalis JH2-2. Reducing the pheromone-responsive conjugation of E. faecalis is of interest because of its clinical importance in the horizontal transfer of antimicrobial resistance. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures

Figure 1

320 KiB

Open AccessArticle

Arsenic Resistance and Prevalence of Arsenic Resistance Genes in Campylobacter jejuni and Campylobacter coli Isolated from Retail Meats

by Aneesa Noormohamed and Mohamed K. Fakhr

Int. J. Environ. Res. Public Health 2013, 10(8), 3453-3464; https://doi.org/10.3390/ijerph10083453 - 07 Aug 2013

Cited by 11 | Viewed by 7351

Abstract

Studies that investigate arsenic resistance in the foodborne bacterium Campylobacter are limited. A total of 552 Campylobacter isolates (281 Campylobacter jejuni and 271 Campylobacter coli) isolated from retail meat samples were subjected to arsenic resistance profiling using the following arsenic compounds: arsanilic [...] Read more.

Studies that investigate arsenic resistance in the foodborne bacterium Campylobacter are limited. A total of 552 Campylobacter isolates (281 Campylobacter jejuni and 271 Campylobacter coli) isolated from retail meat samples were subjected to arsenic resistance profiling using the following arsenic compounds: arsanilic acid (4–2,048 μg/mL), roxarsone (4–2048 μg/mL), arsenate (16–8,192 μg/mL) and arsenite (4–2,048 μg/mL). A total of 223 of these isolates (114 Campylobacter jejuni and 109 Campylobacter coli) were further analyzed for the presence of five arsenic resistance genes (arsP, arsR, arsC, acr3, and arsB) by PCR. Most of the 552 Campylobacter isolates were able to survive at higher concentrations of arsanilic acid (512–2,048 μg/mL), roxarsone (512–2,048 μg/mL), and arsenate (128–1,024 μg/mL), but at lower concentrations for arsenite (4–16 μg/mL). Ninety seven percent of the isolates tested by PCR showed the presence of arsP and arsR genes. While 95% of the Campylobacter coli isolates contained a larger arsenic resistance operon that has all of the four genes (arsP, arsR, arsC and acr3), 85% of the Campylobacter jejuni isolates carried the short operon (arsP, and arsR). The presence of arsC and acr3 did not significantly increase arsenic resistance with the exception of conferring resistance to higher concentrations of arsenate to some Campylobacter isolates. arsB was prevalent in 98% of the tested Campylobacter jejuni isolates, regardless of the presence or absence of arsC and acr3, but was completely absent in Campylobacter coli. To our knowledge, this is the first study to determine arsenic resistance and the prevalence of arsenic resistance genes in such a large number of Campylobacter isolates. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures

Figure 1

261 KiB

Open AccessArticle

Resistance Genes, Phage Types and Pulsed Field Gel Electrophoresis Pulsotypes in Salmonella enterica Strains from Laying Hen Farms in Southern Italy

by Antonio Camarda, Nicola Pugliese, Antonia Pupillo, Marta Oliva, Elena Circella, Anna Maria Dionisi, Antonia Ricci, Marilisa Legretto, Anna Caroli and Carlo Pazzani

Int. J. Environ. Res. Public Health 2013, 10(8), 3347-3362; https://doi.org/10.3390/ijerph10083347 - 06 Aug 2013

Cited by 9 | Viewed by 9470

Abstract

Twenty-four Salmonella enterica isolates (13 serovar Enteritidis and 11 Typhimurium) isolated from 5,600 samples from intensive laying hen farms in Italy in 1998–2007 were characterized for antimicrobial resistance genes, pulsotype and phage type. Most of S. Typhimurium strains were pulsotype STYMXB.0147 (81.8%), phage [...] Read more.

Twenty-four Salmonella enterica isolates (13 serovar Enteritidis and 11 Typhimurium) isolated from 5,600 samples from intensive laying hen farms in Italy in 1998–2007 were characterized for antimicrobial resistance genes, pulsotype and phage type. Most of S. Typhimurium strains were pulsotype STYMXB.0147 (81.8%), phage type DT143 and resistant to sulfamethoxazole encoded by sul2. Two multidrug resistant (MDR) strains were identified. One strain, STYMXB.0061, was resistant to ampicillin (A), chloramphenicol (C), streptomycin (S), sulfamethoxazole (Su) and tetracycline (T) encoded by the Salmonella Genomic Island SGI1. The second MDR strain, STYMXB.0110, was resistant to SSuT encoded by sul1 and sul2, aadA1 and tet(C)-flanked by an IS26 element, respectively. The tet(C) gene has been reported to confer low levels of resistance and it has very rarely been detected in S. Typhimurium from poultry. In the current study, the MIC value (32 µg/mL) was consistent with the breakpoint (³16 µg/mL) reported for Enterobacteriaceae. Most of the S. Enteritidis strains were resistant to Su (encoded by sul2). One MDR strain (ANxSSuT) was identified. With the exception of nalidixic acid (Nx), the resistances were respectively encoded by bla_TEM, strAB, sul2 and tet(A) harbored by an IncN conjugative plasmid. All isolates were pulsotype SENTXB.0001 with PT14b being the most prevalent identified phage type (57.1%). In Europe, SENTXB.0001 is the predominant PFGE profile from clinical cases and the identification of PT14b has steadily been on the increase since 2001. The findings presented in this study highlight the potential spread of S. Enteritidis phage types PT14b and S. Typhimurium DT143 in a field of particular relevance for zoonoses. Additional, the presence of resistance genes and genetic elements (conjugative plasmid and IS element) underlines the need to assess routinely studies in field, such as poultry farms, relevant fot the public health and suitable for the storage and diffusion of antimicrobial resistance. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures

Figure 1

431 KiB

Open AccessArticle

Evaluation of Models Describing the Growth of Nalidixic Acid-Resistant E. coli O157:H7 in Blanched Spinach and Iceberg Lettuce as a Function of Temperature

by Juhui Kim, Hyunjung Chung, Joonil Cho and Kisun Yoon

Int. J. Environ. Res. Public Health 2013, 10(7), 2857-2870; https://doi.org/10.3390/ijerph10072857 - 09 Jul 2013

Cited by 4 | Viewed by 7284

Abstract

The aim of this study was to model the growth of nalidixic acid-resistant E. coli O157:H7 (E. coli O157:H7^NR) in blanched spinach and to evaluate model performance with an independent set of data for interpolation (8.5, 13, 15 and 27 [...] Read more.

The aim of this study was to model the growth of nalidixic acid-resistant E. coli O157:H7 (E. coli O157:H7^NR) in blanched spinach and to evaluate model performance with an independent set of data for interpolation (8.5, 13, 15 and 27 °C) and for extrapolation (broth and fresh-cut iceberg lettuce) using the ratio method and the acceptable prediction zone method. The lag time (LT), specific growth rate (SGR) and maximum population density (MPD) obtained from each primary model were modeled as a function of temperature (7, 10, 17, 24, 30, and 36 °C) using Davey, square root, and polynomial models, respectively. At 7 °C, the populations of E. coli O157:H7^NR increased in tryptic soy broth with nalidixic acid (TSBN), blanched spinach and fresh-cut iceberg lettuce, while the populations of E. coli O157:H7 decreased in TSB after 118 h of LT, indicating the risk of nalidixic acid-resistant strain of E. coli O157:H7 contaminated in ready-to-eat produce at refrigerated temperature. When the LT and SGR models of blanched spinach was extended to iceberg lettuce, all relative errors (percentage of RE = 100%) were inside the acceptable prediction zone and had an acceptable B_f and A_f values. Thus, it was concluded that developed secondary models for E. coli O157:H7^NR in blanched spinach were suitable for use in making predictions for fresh cut iceberg lettuce, but not for static TSBN in this work. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures

Figure 1

211 KiB

Open AccessArticle

Outbreak of Ampicillin/Piperacillin-Resistant Klebsiella Pneumoniae in a Neonatal Intensive Care Unit (NICU): Investigation and Control Measures

by Giuliana Fabbri, Manuela Panico, Laura Dallolio, Roberta Suzzi, Matilde Ciccia, Fabrizio Sandri and Patrizia Farruggia

Int. J. Environ. Res. Public Health 2013, 10(3), 808-815; https://doi.org/10.3390/ijerph10030808 - 26 Feb 2013

Cited by 16 | Viewed by 7694

Abstract

Klebsiella pneumoniae is a frequent cause of infectious outbreaks in Neonatal Intensive Care Units (NICUs). The aim of this paper is to describe an outbreak occurred in a 13-bed NICU and the control measures adopted in order to interrupt the chain of transmission. [...] Read more.

Klebsiella pneumoniae is a frequent cause of infectious outbreaks in Neonatal Intensive Care Units (NICUs). The aim of this paper is to describe an outbreak occurred in a 13-bed NICU and the control measures adopted in order to interrupt the chain of transmission. We described the microbiological investigations, the NICU staff compliance to the infection control measures by means of a specifically designed check-list and the control measures adopted. Six cases of primary bloodstream infections sustained by ampicillin/piperacillin-resistant Klebsiella pneumoniae were observed over a two-month period. One culture obtained from a 12% saccarose multiple-dose solution allowed the growth of Klebsiella pneumoniae. During the inspections performed by the Hospital Infection Control Team, using the check-list for the evaluation of the NICU staff compliance to the infection control measures, several breaches in the infection control policy were identified and control measures were adopted. In our case the definition of a specific check-list led to the adoption of the correct control measures. Further studies would be helpful in order to develop a standard check-list able to identify critical flows in the adhesion to the guidelines. It could be used in different NICUs and allow to obtain reproducible levels of infection control. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures

Figure 1

Review

Jump to: Research

236 KiB

Open AccessReview

Escherichia coli in Europe: An Overview

by Nerino Allocati, Michele Masulli, Mikhail F. Alexeyev and Carmine Di Ilio

Int. J. Environ. Res. Public Health 2013, 10(12), 6235-6254; https://doi.org/10.3390/ijerph10126235 - 25 Nov 2013

Cited by 279 | Viewed by 45774

Abstract

Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently [...] Read more.

Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently associated with diarrhoea in pet and farm animals. The therapeutic treatment of E. coli infections is threatened by the emergence of antimicrobial resistance. The prevalence of multidrug-resistant E. coli strains is increasing worldwide principally due to the spread of mobile genetic elements, such as plasmids. The rise of multidrug-resistant strains of E. coli also occurs in Europe. Therefore, the spread of resistance in E. coli is an increasing public health concern in European countries. This paper summarizes the current status of E. coli strains clinically relevant in European countries. Furthermore, therapeutic interventions and strategies to prevent and control infections are presented and discussed. The article also provides an overview of the current knowledge concerning promising alternative therapies against E. coli diseases. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

723 KiB

Open AccessReview

Strategies to Minimize Antibiotic Resistance

by Chang-Ro Lee, Ill Hwan Cho, Byeong Chul Jeong and Sang Hee Lee

Int. J. Environ. Res. Public Health 2013, 10(9), 4274-4305; https://doi.org/10.3390/ijerph10094274 - 12 Sep 2013

Cited by 294 | Viewed by 31472

Abstract

Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs) and various data such as pharmacokinetic (PK) and pharmacodynamic (PD) properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST), clinical response, and effects on the microbiota, [...] Read more.

Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs) and various data such as pharmacokinetic (PK) and pharmacodynamic (PD) properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST), clinical response, and effects on the microbiota, as well as by new antibiotic developments. The controlled use of antibiotics in food animals is another cornerstone among efforts to reduce antibiotic resistance. All major resistance-control strategies recommend education for patients, children (e.g., through schools and day care), the public, and relevant healthcare professionals (e.g., primary-care physicians, pharmacists, and medical students) regarding unique features of bacterial infections and antibiotics, prudent antibiotic prescribing as a positive construct, and personal hygiene (e.g., handwashing). The problem of antibiotic resistance can be minimized only by concerted efforts of all members of society for ensuring the continued efficiency of antibiotics. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures

Graphical abstract

354 KiB

Open AccessReview

Antimicrobial Resistance in the Food Chain: A Review

by Claire Verraes, Sigrid Van Boxstael, Eva Van Meervenne, Els Van Coillie, Patrick Butaye, Boudewijn Catry, Marie-Athénaïs De Schaetzen, Xavier Van Huffel, Hein Imberechts, Katelijne Dierick, Georges Daube, Claude Saegerman, Jan De Block, Jeroen Dewulf and Lieve Herman

Int. J. Environ. Res. Public Health 2013, 10(7), 2643-2669; https://doi.org/10.3390/ijerph10072643 - 28 Jun 2013

Cited by 412 | Viewed by 26260

Abstract

Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance [...] Read more.

Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. Food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. A first way is the presence of antibiotic resistant bacteria on food selected by the use of antibiotics during agricultural production. A second route is the possible presence of resistance genes in bacteria that are intentionally added during the processing of food (starter cultures, probiotics, bioconserving microorganisms and bacteriophages). A last way is through cross-contamination with antimicrobial resistant bacteria during food processing. Raw food products can be consumed without having undergone prior processing or preservation and therefore hold a substantial risk for transfer of antimicrobial resistance to humans, as the eventually present resistant bacteria are not killed. As a consequence, transfer of antimicrobial resistance genes between bacteria after ingestion by humans may occur. Under minimal processing or preservation treatment conditions, sublethally damaged or stressed cells can be maintained in the food, inducing antimicrobial resistance build-up and enhancing the risk of resistance transfer. Food processes that kill bacteria in food products, decrease the risk of transmission of antimicrobial resistance. Full article

(This article belongs to the Special Issue Antimicrobial Resistance Prevention and Control)

► Show Figures