Distribution of Antimicrobial Resistance in Campylobacter Strains Isolated from Poultry at a Slaughterhouse and Supermarkets in Japan

Development of a Sampling and Real-time PCR Method for the Quantitative Detection of Campylobacter spp. in Retail Chicken Meat Without DNA Extraction

Campylobacter food poisoning is caused by consumption of the contaminated foods, especially poultry meat. Continuous quantitative measurement of Campylobacter spp. in contaminated foods is crucial to develop preventive measures. We developed a direct-qPCR method for determining the viable cell counts of Campylobacter spp. using qPCR without DNA extraction from enriched food samples and a sampling method (the wrap procedure) in which the sample is wrapped in a sheet, different from the conventional homogenization procedure. The viable cell counts of Campylobacter spp. before and after enrichment of the samples sampled using the wrap and homogenization procedures from chicken samples inoculated with Campylobacter jejuni were determined using the culture method, and the cycle threshold (C_T) values after enrichment were determined using the direct-qPCR. An enrichment regression equation was generated from the viable cell counts obtained before and after enrichment, and a direct-qPCR regression equation was generated from the C_T values and viable cell counts obtained after enrichment, enabling the viable cell counts before enrichment to be estimated from the C_T values. Estimated viable cell counts were similar for the culture method when sampled by the homogenization procedure, but lower for the wrap procedure. However, the detection rate of direct-qPCR was 37.5% for liver and 89.7% for breast fillet using the homogenization procedure, whereas using the wrap procedure, it was 100% for both samples. The detection rate of direct-qPCR for retail chicken was 30.4-35.7% for the homogenization procedure, and 85.7-100% for the wrap procedure. Colonies were observed using the culture method, but their quantification was difficult due to swarming or their low number. However, estimating viable cell counts using the combination of wrap procedure and direct-qPCR methods is possible. The developed method can provide baseline data for the risk assessment Campylobacter food poisoning.

Highly Prevalent Multidrug-Resistant Campylobacter spp. Isolated From a Yellow-Feathered Broiler Slaughterhouse in South China

The purpose of this study was to investigate the prevalence, antimicrobial resistance, virulence genes, and genetic diversity of Campylobacter spp. along the yellow-feathered broiler slaughtering line in Southern China from December 2018 to June 2019. A total of 157 Campylobacter spp. isolates were identified from 1,102 samples (including 53.6% (75/140) of live chicken anal swab samples, 27.5% (44/160) of defeathering samples, 18.1% (29/160) of evisceration samples, 2.1% (3/140) of washing samples, 1.4% (2/140) of chilling samples, and 1.1% (4/362) of environmental samples). The prevalence of Campylobacter spp. was 14.2%, including 43.9% Campylobacter jejuni, 53.5% Campylobacter coli, and 2.5% other Campylobacter species. The highest antimicrobial resistance rate was found to be against sulfamethoxazole (138/157, 87.9%), and 90.4% (142/157) of the isolates were multidrug resistant (MDR). Examination of resistance-related genes revealed the double base mutated Thr-86-Ile, which informed ACA-TTA, with an Arg-79-Lys substitution in gyrA. Eleven virulence-associated genes (cadF, cdtA, cdtB, ciaB, flaA, imaA, dnaJ, plaA, virB11, racR, and cdtC) were also detected by a polymerase chain reaction (PCR) analysis, and cadF (81.5%) was the most prevalent. Based on an analysis of pulsed-field gel electrophoresis (PFGE) results, we found that Campylobacter spp. could be cross-contaminated throughout the entire slaughtering line. These results show that it is imperative to study the Campylobacter spp. from the yellow-feathered broiler along the slaughtering line in China to develop preventative and treatment measures for the poultry industry, as well as food safety and public health.

Acinetobacter baumannii detected on modified charcoal–cefoperazone–deoxycholate agar in a waste stabilization pond

Campylobacter is a recommended reference pathogen for the verification and validation of water recycling schemes in Australia and globally. In a larger study investigating the efficacy of pathogen removal in waste stabilization ponds (WSP), we cultivated bacteria from wastewater samples on modified charcoal–cefoperazone–deoxycholate agar (mCCDA) targeting the growth of Campylobacter. A high number of colonies characteristic of Campylobacter grew on this selective medium, but this did not correlate with qPCR data. Using primers targeting the 16S rRNA gene, and additional confirmatory tests to detect VS1, ompA, blaOXA-51-like, blaOXA-23-like genes, we tested 80 random colonies from 10 WSP samples. All 80 were identified as Acinetobacter baumannii. Wastewater grab samples taken three times over 6 months throughout the WSP system showed removal of A. baumannii in the WSP at rates similar to that of Escherichia coli. Our study suggests that mCCDA agar is not a suitable medium for isolating Campylobacter from environmental samples and that A. baumannii can be used as an indicator for removal of pathogens in WSPs.

Ashworth A, Ricke SC. A Historical Review on Antibiotic Resistance of Foodborne Campylobacter

Campylobacter is one of the most commonly reported foodborne human bacterial gastrointestinal pathogens. Campylobacter is the etiological agent of campylobacteriosis, which is generally a self-limited illness and therefore does not require treatment. However, when patients are immunocompromised or have other co-morbidities, antimicrobial treatment may be necessary for clinical treatment of campylobacteriosis, macrolides and fluoroquinolones are the drugs of choices. However, the increase in antimicrobial resistance of Campylobacter to clinically important antibiotics may become insurmountable. Because of the transmission between poultry and humans, the poultry industry must now allocate resources to address the problem by reducing Campylobacter as well as antimicrobial use, which may reduce resistance. This review will focus on the incidence of antibiotic-resistant Campylobacter in poultry, the clinical consequences of this resistance, and the mechanisms of antibiotic resistance associated with Campylobacter.

Emerging erm(B)-Mediated Macrolide Resistance Associated with Novel Multidrug Resistance Genomic Islands in Campylobacter

The rapid dissemination of the macrolide resistance gene erm(B) will likely compromise the efficacy of macrolides as the treatment of choice for campylobacteriosis. More importantly, erm(B) is always associated with several multidrug resistance genomic islands (MDRGIs), which confer resistance to multiple other antimicrobials. Continuous monitoring of the emergence of erm(B) and analysis of its associated genetic environments are crucial for our understanding of macrolide resistance in Campylobacter In this study, 290 Campylobacter isolates (216 Campylobacter coli isolates and 74 Campylobacter jejuni isolates) were obtained from 1,039 fecal samples collected in 2016 from pigs and chickens from three regions of China (344 samples from Guangdong, 335 samples from Shanghai, and 360 samples from Shandong). Overall, 74 isolates (72 C. coli isolates and 2 C. jejuni isolates) were PCR positive for erm(B). Combined with data from previous years, we observed a trend of increasing prevalence of erm(B) in C. coli Pulsed-field gel electrophoresis analyses suggested that both clonal expansion and horizontal transmission were involved in the dissemination of erm(B) in C. coli, and three novel types of erm(B)-associated MDRGIs were identified among the isolates. Furthermore, 2 erm(B)-harboring C. jejuni isolates also contained an aminoglycoside resistance genomic island and a multidrug-resistance-enhancing efflux pump, encoded by RE-cmeABC Antimicrobial susceptibility testing showed that most of the isolates were resistant to all clinically important antimicrobial agents used for the treatment of campylobacteriosis. These findings suggest that the increasing prevalence of erm(B)-associated MDRGIs might further limit treatment options for campylobacteriosis.

Long-term observation of antimicrobial susceptibility and molecular characterisation of Campylobacter jejuni isolated in a Japanese general hospital 2000-2017

OBJECTIVES

Campylobacter jejuni (C. jejuni) is one of the most common pathogens that causes gastroenteritis. Because there is currently insufficient epidemiological information about the antimicrobial susceptibility and molecular characterisation of clinical isolates of C. jejuni in Japan, this study carried out antimicrobial susceptibility testing and multilocus sequence typing (MLST) of clinical C. jejuni isolates in Tokyo between 2000-2017.

METHODS

Antimicrobial susceptibility to erythromycin and ciprofloxacin was tested using the broth microdilution method in 430 C. jejuni clinical isolates collected over 18 years, between 2000-2017, at a Tokyo general hospital. To observe the sequence type (ST) evolution, 82 isolates were chosen from three non-consecutive years (16 isolates from 2000, 25 isolates from 2008, and 41 isolates from 2017) and analysed by MLST as a molecular characterisation test. Mutations in the quinolone resistance-determining region of the gyrA and gyrB genes were identified.

RESULTS

The rate of resistance to erythromycin was low, but that of ciprofloxacin resistance was 34.9% in 2000-2008 and 41.9% in 2009-2017. The most common clonal complex (CC) identified during the entire period was CC21; ST4526 with ciprofloxacin resistance was highly prevalent in 2017 (6 of 11; 54.5%).

CONCLUSION

The results indicate that the rate of resistance to quinolone has gradually increased. Since ST4526 was not isolated in 2000 and 2008, it is likely that ST4526 is rapidly increasing in Japan.

Preincubation of Escherichia coli ATCC 25922 with NaCl Increases Its Attachment to Lettuce Surfaces Compared with Other Chemicals

　The inhibition of microbial attachment to food is important for the prevention of cross-contamination during food processing. The effect of several chemicals that were added in an Escherichia coli growth medium on the attachment of the bacterium to lettuce was investigated. E. coli ATCC 25922, which is reportedly a useful surrogate for E. coli O157:H7 in surface attachment studies, was preincubated in a nutrient broth (NB) containing sodium chloride, potassium chloride, sodium deoxycholate, sodium linear alkylbenzene sulfonate, or sorbic acid. The bacterial cells were placed in contact with cut lettuce in a saline solution at 5℃ for 24 hours. Only the addition of NaCl in the NB influenced the attachment of E. coli, Salmonella enterica subsp. Enteritidis, and Klebsiella pneumoniae to the lettuce. The attachment of E. coli showed the largest significant increase at 2% NaCl. Changes in the attachment levels were not due to surface hydrohobicity or the motility of E. coli cells. Similar results were observed for S. enterica although the variation in the degree of attachment of the latter was quite small. These results suggested that the attachment of E. coli O157:H7 to food surfaces is influenced by the bacterial growth conditions prior to food exposure and prior to the development of the biofilm; furthermore, the environmental NaCl concentration should be controlled during food processing to prevent the cross-contamination of foods with E. coli.