Antimicrobial susceptibility of Campylobacter jejuni subsp. jejuni assessed by E-test and double dilution agar method in Southern Chile

The Enterotoxin Production and Antimicrobial Resistance of Campylobacter Strains Originating from Slaughter Animals

The pathogenicity of animal-origin Campylobacter strains, including antimicrobial resistance and enterotoxigenicity, was determined in this study. Overall, 149 Campylobacter isolates originating from cattle, swine and poultry were tested. The antimicrobial resistance profiles were examined by the diffusion disk method. The dominant resistance pattern was CIP_TET. The resistance rates for ciprofloxacin among swine, cattle and poultry isolates were 84%, 51% and 66%, respectively; for tetracycline, they were 82%, 57.1% and 76%, respectively. None of the obtained isolates was resistant to all four antimicrobials tested. The ability to produce enterotoxins was assessed by the use of a suckling mouse bioassay, with intestinal fluid accumulation as a positive result, and by CHO assay, with the elongation of cells as a positive result. The ability to produce enterotoxins was significantly higher among cattle isolates (61.2% and 71.4% positive isolates, respectively, in the bioassay and the CHO assay) than among swine (16% and 32% positive isolates, respectively) or poultry isolates (14% and 22% positive isolates, respectively). A strong positive correlation between in vitro and in vivo enterotoxicity tests was demonstrated.

Genomic Analysis of Chilean Strains of Campylobacter jejuni from Human Faeces

Campylobacter spp., especially C. jejuni, are recognized worldwide as the bacterial species that most commonly cause food-related diarrhea. C. jejuni possesses many different virulence factors, has the ability to survive in different reservoirs, and has shown among isolates the emergence of Antimicrobial Resistance (AMR). Genome association analyses of this bacterial pathogen have contributed to a better understanding of its pathogenic and AMR associated determinants. However, the epidemiological information of these bacteria in Latin American countries is scarce and no genomic information is available in public databases from isolates in these countries. Considering this, the present study is aimed to describe the genomic traits from representative Campylobacter spp. strains recovered from faecal samples of patients with acute diarrhoea from Valparaíso, Chile. Campylobacter spp. was detected from the faeces of 28 (8%) out of 350 patients with acute diarrhoea, mainly from young adults and children, and 26 (93%) of the isolates corresponded to C. jejuni. 63% of the isolates were resistant to ciprofloxacin, 25.9% to tetracycline, and 3.5% to erythromycin. Three isolates were selected for WGS on the basis of their flaA-RFLP genotype. They belonged to the multilocus sequence typing (MLST) clonal clomplex (CC) 21(PUCV-1), CC-48 (PUCV-3), and CC-353 (PUCV-2) and presented several putative virulence genes, including the Type IV and Type VI Secretion Systems, as well as AMR-associated genes in agreement with their susceptibility pattern. On the basis of the wgMLST, they were linked to strains from poultry and ruminants. These are the first genomes of Chilean C. jejuni isolates available in public databases and they provide relevant information about the C. jejuni isolates associated with human infection in this country.

Campylobacter Insulaenigrae: First Isolation Report from South American sea lion (Otaria Flavescens, (Shaw, 1800)

Campylobacter insulaenigrae have been isolated from different pinnipeds but not from South American sea lion (Otaria flavescens).The aim of this work is to report the first isolation of C. insulaenigrae from South American sea lion (Otaria flavescens).The isolate, identified by its phenotypic and molecular characteristics, allow recognizing O. flavescens as a new host for C. insulaenigrae.

Antimicrobial resistance in campylobacter: susceptibility testing methods and resistance trends

Most Campylobacter infections are self-limiting but antimicrobial treatment (e.g., macrolides, fluoroquinolones) is necessary in severe or prolonged cases. Susceptibility testing continues to play a critical role in guiding therapy and epidemiological monitoring of resistance. The methods of choice for Campylobacter recommended by the Clinical and Laboratory Standards Institute (CLSI) are agar dilution and broth microdilution, while a disk diffusion method was recently standardized by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Macrolides, quinolones, and tetracyclines are among the common antimicrobials recommended for testing. Molecular determination of Campylobacter resistance via DNA sequencing or PCR-based methods has been performed. High levels of resistance to tetracycline and ciprofloxacin are frequently reported by many national surveillance programs, but resistance to erythromycin and gentamicin in Campylobacter jejuni remains low. Nonetheless, variations in susceptibility observed over time underscore the need for continued public health monitoring of Campylobacter resistance from humans, animals, and food.

Campylobacter antimicrobial resistance in Peru: a ten-year observational study

Background

Campylobacter jejuni and Campylobacter coli are food-borne pathogens of great importance and feature prominently in the etiology of developing world enteritis and travellers’ diarrhoea. Increasing antimicrobial resistant Campylobacter prevalence has been described globally, yet data from Peru is limited. Our objective was to describe the prevalence trends of fluoroquinolone and macrolide-resistant C. jejuni and C. coli stool isolates from three regions in Peru over a ten-year period.

Methods

Surveillance for enteric pathogens was conducted in Lima, Iquitos and Cusco between 2001 and 2010. Campylobacter stool isolates were tested for susceptibilities to ciprofloxacin, azithromycin and erythromycin. Susceptibilities were reviewed for 4652 isolates from Lima ( n = 3419), Iquitos ( n = 625) and Cusco ( n = 608).

Results

Comparing the study periods of 2001-2005 and 2006-2010, prevalence of ciprofloxacin-resistant C. jejuni isolates rose in the study areas of Lima (73.1% to 89.8%, p < 0.001) and Iquitos (24.1% to 48.9%, p < 0.001). Ciprofloxacin-resistant C. coli rates also increased in Lima (48.1% to 87.4%, p < 0.001) and Cusco (10.0% to 65.9%, p = 0.005). Small but significant increases in azithromycin-resistant and erythromycin-resistant C. jejuni prevalence were noted in Iquitos (2.2% to 14.9%, p < 0.001; 3.2% to 14.9%, p = 0.002), and erythromycin-resistant C. coli rates increased in Lima (0.0% to 5.3%, p = 0.038). The prevalence of C. jejuni isolates resistant to both ciprofloxacin and azithromycin increased in Iquitos (0.3% to 14.9%, p < 0.001) and Lima (0.3% to 1.6%, p = 0.011), and prevalence of C. jejuni isolates resistant to both ciprofloxacin and erythromycin rose in Iquitos (0.0% to 14.9%, p < 0.001). Ciprofloxacin and erythromycin resistant C. coli prevalence increased in Lima (0.0% to 5.3%, p = 0.034).

Conclusions

These results have implications for the empirical management of enterocolitis in Peru. Ongoing surveillance is essential to guide appropriate antimicrobial use in this setting. Local epidemiological studies to explore the relationship between increasing antimicrobial resistance and agricultural or human antibiotic use may be valuable.

Inaccuracy of routine susceptibility tests for detection of erythromycin resistance of Campylobacter jejuni and Campylobacter coli

In The Netherlands, both an increase in and regional differences in erythromycin resistance of Campylobacter jejuni and Campylobacter coli have been reported. To determine the accuracy of routine tests for erythromycin resistance, 48 erythromycin-resistant isolates from various laboratories that participate in the Dutch surveillance of Campylobacter infections were reinvestigated. Initial susceptibility testing for erythromycin had been performed by disk diffusion in six and MIC-based methods in two laboratories. Reinvestigation was carried out using broth microdilution as a reference standard, as well as E-test and genetic resistance testing. Of 36 C. jejuni isolates reported by the initial laboratories as erythromycin-resistant, four (11%) and five (14%) were confirmed as erythromycin-resistant using broth microdilution according to CLSI and EUCAST resistance criteria, respectively. Erythromycin resistance was found in eight of 12 (67%) C. coli isolates according to both criteria. Results of E-tests were in accordance with these results in all isolates. Resistance-associated mutations in the 23S rRNA gene (A2059G and A2058T) were found in all isolates showing high-level resistance, whereas none were found in susceptible isolates. Routine determination of the erythromycin resistance of C. jejuni and C. coli shows unacceptable interlaboratory variation. In the absence of standardized protocols and interpretive criteria for disk diffusion, and while we await the development of easily applicable and reliable methods for molecular resistance testing, the use of broth microdilution remains the best method.

Antimicrobial resistance of Campylobacter species isolated from edible bivalve molluscs purchased from Bangkok markets, Thailand

Campylobacter species have been recognized as the most commonly reported cause of bacterial gastroenteritis in humans. The increase of resistance rates to drugs of choice used for treatment in campylobacteriosis is becoming a public health concern. In parallel, the increased use of antimicrobials in aquaculture may lead to the emergence of resistant microorganisms and is likely to cause additional health risk to humans through food consumption. The study assesses the presence of antimicrobial resistance in Campylobacter species isolated from three groups of bivalve molluscs (bloody cockles, green mussels, and oysters) purchased from markets in Bangkok. Thirty samples were collected from each group. Susceptibility to three antimicrobials was determined using the Epsilometer test. Rates of erythromycin, nalidixic acid, and ciprofloxacin resistance in Campylobacter isolates were 72-84%, 28-40%, and 21-25%, respectively. There was no statistically significant difference in the prevalence of each antimicrobial resistance between the three groups. This study demonstrates a significant level of antimicrobial resistance in the Campylobacter spp. isolated from molluscs with a particular high rate of resistance to erythromycin. Consumption of raw molluscs contaminated with antimicrobial-resistant Campylobacter spp. may therefore result in resistant infections in humans.

Trends of norfloxacin and erythromycin resistance of Campylobacter jejuni/Campylobacter coli isolates recovered from international travelers, 1994 to 2006

BACKGROUND

Campylobacter sp. is a major cause of bacterial enterocolitis and travelers' diarrhea. Empiric treatment regimens include fluoroquinolones and macrolides.

METHODS

Over the period 1994 to 2006, 724 Campylobacter jejuni/Campylobacter coli isolates recovered from international travelers at the outpatient clinic of the Institute of Tropical Medicine, Antwerp, Belgium, were reviewed for their susceptibility to norfloxacin and erythromycin.

RESULTS

Norfloxacin resistance increased significantly over time in isolates from travelers returning from Asia, Africa, and Latin America. For the years 2001 to 2006, norfloxacin resistance rates were 67 (70.5%) of 95 for Asia, 20 (60.6%) of 33 for Latin America, and 36 (30.6%) of 114 for Africa. The sharpest increase was noted for India, with no resistance in 1994, but 41 (78.8%) of 52 resistant isolates found during 2001 to 2006. Erythromycin resistance was demonstrated in 20 (2.7%) isolates, with a mean annual resistance of 3.1% +/- 2.8%; resistance increased over time, with up to 3(7.5%) of 40 and 3 (8.6%) of 35 resistant isolates in 2004 and 2006, respectively (p < 0.05); there was no apparent geographic association. Combined resistance to norfloxacin and erythromycin was observed in five isolates.

CONCLUSIONS

The high resistance rates to fluoroquinolones warrant reconsideration of their use as drugs of choice in patients with severe gastroenteritis when Campylobacter is the presumed cause. Continued monitoring of the incidence and the spread of resistant Campylobacter isolates is warranted.

Comparison of antimicrobial susceptibility testing of Campylobacter spp. by the agar dilution and the agar disk diffusion methods

The correlation and the level of agreement between the standardized agar dilution and the agar disk diffusion methods for antimicrobial susceptibility testing of Campylobacter were investigated. A high-level agreement between the two methods was evident for aminoglycosides and fluoroquinolones, while a low-level agreement was observed for other antibiotics.

Characterization of erythromycin resistance in Campylobacter coli and Campylobacter jejuni isolated from pig offal in New Zealand

AIMS

To determine the level and mechanism(s) of antimicrobial resistance in Campylobacter isolates obtained from human and environmental sources from South Canterbury, New Zealand.

METHODS AND RESULTS

A total of 251 Campylobacter isolates were tested for susceptibility to ciprofloxacin, erythromycin, nalidixic acid and tetracycline using disc diffusion assays. Five pig offal isolates were observed to be highly erythromycin resistant, with minimal inhibitory concentrations determined to be >/=256 microg ml(-1). Nucleotide sequencing of the 23S ribosomal DNA (rDNA) in these resistant isolates identified an A --> G change at Escherichia coli position 2059 that has been previously implicated in erythromycin resistance in Campylobacter coli. Macrorestriction profiling using pulsed-field gel electrophoresis showed these isolates were nonclonal.

CONCLUSIONS

The majority of Campylobacter isolates from South Canterbury remain sensitive to the most clinically relevant antimicrobial agents. Our results support other reports showing that specific variations in the 23S rDNA contribute to erythromycin resistance.

SIGNIFICANCE AND IMPACTS OF THE STUDY

This study defines the baseline frequency of antimicrobial resistance associated with Campylobacter isolates from South Canterbury, and discusses the likely molecular mechanisms conferring erythromycin resistance in this organism. Resistance to erythromycin in these isolates is not linked to a dominant Campylobacter clone and has likely arisen independently in different genetic lines exposed to selective antimicrobial pressure.

Fluoroquinolone Susceptibility of Campylobacter Strains, Senegal

To assess fluoroquinolone susceptibility of Campylobacter strains in Senegal, skin samples were collected from 250 chicken carcasses from January 2001 to October 2002. Among 205 isolated Campylobacter strains, 59% and 41% were identified as Campylobacter jejuni and C. coli, respectively; the overall ciprofloxacin-resistance rate was 34%.

Rapid detection of mutations associated with resistance to erythromycin in Campylobacter jejuni/coli by PCR and line probe assay

Mutation of 23S rDNA is one of the mechanisms of erythromycin resistance. PCR and line probe assay (PCR-LiPA) with ten oligonucleotide probes were developed to detect the mutations associated with macrolide resistance at positions of 2072, 2073 and 2074 in 23S rDNA of Campylobacter jejuni/coli. A2074-->G mutation was detected in 12 of 25 isolates, which were resistant to erythromycin. No other mutations in 23S rDNA were detected. The rest of the strains were susceptible to erythromycin and no mutation in 23S rDNA was detected. Six laboratory induced erythromycin resistant mutants had no mutations in 23S rDNA. PCR-LiPA is a useful and rapid method to detect mutations in 23S rDNA associated with erythromycin resistance in C. jejuni/coli.