Antimicrobial resistance mechanisms among Campylobacter

Food-to-Humans Bacterial Transmission

Microorganisms vehiculated by food might benefit health, cause minimal change within the equilibrium of the host microbial community or be associated with foodborne diseases. In this chapter we will focus on human pathogenic bacteria for which food is conclusively demonstrated as their transmission mode to human. We will describe the impact of foodborne diseases in public health, the reservoirs of foodborne pathogens (the environment, human and animals), the main bacterial pathogens and food vehicles causing human diseases, and the drivers for the transmission of foodborne diseases related to the food-chain, host or bacteria features. The implication of food-chain (foodborne pathogens and commensals) in the transmission of resistance to antibiotics relevant to the treatment of human infections is also evidenced. The multiplicity and interplay of drivers related to intensification, diversification and globalization of food production, consumer health status, preferences, lifestyles or behaviors, and bacteria adaptation to different challenges (stress tolerance and antimicrobial resistance) from farm to human, make the prevention of bacteria-food-human transmission a modern and continuous challenge. A global One Health approach is mandatory to better understand and minimize the transmission pathways of human pathogens, including multidrug-resistant pathogens and commensals, through food-chain.

Thermotolerant Campylobacter spp. in chicken and bovine meat in Italy: Prevalence, level of contamination and molecular characterization of isolates

Campylobacter species are common foodborne pathogens associated with cases of human gastroenteritis worldwide. A detailed understanding of the prevalence, contamination levels and molecular characteristics of Campylobacter spp. in cattle and chicken, which are likely the most important sources of human contamination, is imperative. A collection of 1243 poultry meat samples (665 chicken breasts and 578 chicken thighs) and 1203 bovine meat samples (689 hamburgers and 514 knife-cut meat preparations) were collected at retail outlets, in randomly selected supermarkets located in different Italian regions during one year. Of these samples, 17.38% of the poultry meat and 0.58% of the bovine meat samples tested positive for Campylobacter, of which 131 were Campylobacter jejuni (57.96%) and 95 were Campylobacter coli (42.03%). Campylobacter isolates were genotyped with the aim of assessing the genetic diversity, population structure, source distribution and Campylobacter transmission route to humans. All isolates were molecularly characterized by pulse field gel electrophoresis (PFGE), and further genotyped using multilocus sequence typing (MLST) and fla-SVR sequencing to gain better insight into the population structure. Antibiotic resistance was also investigate. The highest levels of resistance among chicken strains were observed for ciprofloxacin (88.25%), nalidixic acid (81.45%) and tetracycline (75.6%). PFGE analysis revealed 73 pulsotypes for C. jejuni and 54 pulsotypes for C. coli, demonstrating the existance of different and specific clones circulating in Italy. MLST of C.jejuni isolates mainly clustered in the CC353, CC354, CC21, CC206 and CC443; while C.coli isolates clustered only in CC828. The most common flaA alleles were 287 for C. jejuni and 66 for C. coli. Our study confirms that poultry meat is the main source of Campylobacteriosis, whereas red meat had a low level of contamination suggesting a minor role in transmission. The high presence of Campylobacter in retail chicken meat, paired with its increased resistance to antimicrobials with several multidrug resistance profiles detected, is alarming and represents a persistent threat to public health.

Acquisition of fluoroquinolone resistance leads to increased biofilm formation and pathogenicity in Campylobacter jejuni

The World Health Organization has listed C. jejuni as one of 12 microorganisms on a global priority list for antibiotic resistance due to a rapid increase in strains resistant to fluoroquinolone antibiotics. This fluoroquinolone resistance is conferred through a single point mutation in the QRDR region within the gyrA gene known to be involved in DNA supercoiling. We have previously revealed that changes in DNA supercoilikng play a major role in the regulation of virulence in C. jejuni with relaxation of DNA supercoiling associated with increased attachment to and invasion of human epithelial cells. The aim of this study was to investigate whether fluoroquinolone resistant strains of C. jejuni displayed altered supercoiling associated phenotypes. A panel of fluoroquinolone resistant mutants were derived and shown to have a greater ability to form viable biofilms under aerobic conditions, invade epithelial cells and promote virulence in the Galleria mellonella model of infection. We thus report for the first time that fluoroquinolone resistance in C. jejuni is associated with an increase in virulence and the ability to form viable biofilms in oxygen rich environments. These altered phenotypes likely play a critical role in the continued increase in fluoroquinolone resistance observed for this important pathogen.

Molecular Epidemiology and Resistance Profile of Campylobacter jejuni and Campylobacter coli Strains Isolated from Different Sources in Brazil

Aims: The objectives of this study were to genotype a total of 48 Campylobacter jejuni and 39 Campylobacter coli strains isolated in Brazil from 1995 to 2016 by multilocus sequence typing (MLST) and to determine their resistance profile. The presence or points of mutation in the related resistance genes was verified. Results: By MLST, C. jejuni strains were typed into 36 STs and C. coli strains were typed into 27 STs. A total of 70.8% of C. jejuni and 35.9% of C. coli were resistant to at least one antimicrobial tested. The tet(O) gene was detected in 43.7% C. jejuni and in 12.8% C. coli. The ermB gene was not detected and one C. jejuni presented the mutation in the 23S rRNA gene. Besides, 58.3% C. jejuni presented the substitution T86I in the quinolone resistance-determining region of gyrA and 15.4% C. coli presented the substitution T38I. The cmeB gene was detected in 97.9% C. jejuni and in 97.4% C. coli. Conclusion: The presence of C. jejuni and C. coli resistant to some antimicrobial agents of clinical use is of public health concern. The presence of STs shared between Brazilian strains and isolates of different countries is of concern since it might suggest a possible spread of these shared types.

Campylobacter jejuni isolated from poultry meat in Brazil: in silico analysis and genomic features of two strains with different phenotypes of antimicrobial susceptibility

Campylobacter jejuni is the most common bacterial cause of foodborne diarrheal disease worldwide and is among the antimicrobial resistant "priority pathogens" that pose greatest threat to public health. The genomes of two C. jejuni isolated from poultry meat sold on the retail market in Southern Brazil phenotypically characterized as multidrug-resistant (CJ100) and susceptible (CJ104) were sequenced and analyzed by bioinformatic tools. The isolates CJ100 and CJ104 showed distinct multilocus sequence types (MLST). Comparative genomic analysis revealed a large number of single nucleotide polymorphisms, rearrangements, and inversions in both genomes, in addition to virulence factors, genomic islands, prophage sequences, and insertion sequences. A circular 103-kilobase megaplasmid carrying virulence factors was identified in the genome of CJ100, in addition to resistance mechanisms to aminoglycosides, beta-lactams, macrolides, quinolones, and tetracyclines. The molecular characterization of distinct phenotypes of foodborne C. jejuni and the discovery of a novel virulence megaplasmid provide useful data for pan-genome and large-scale studies to monitor the virulent C. jejuni in poultry meat is warranted.

Investigation of molecular mechanisms underlying tetracycline resistance in thermophilic Campylobacter spp. suggests that previous reports of tet(A)-mediated resistance in these bacteria are premature

The true prevalence of tet(A), which codes for a tetracycline efflux pump, in thermophilic Camplyobacter spp. requires clarification after reports emerged in Iran (2014) and Kenya (2016) of the novel detection of tet(A) in Campylobacter. During our investigation of antibiotic resistance mechanisms in a sample of Irish thermophilic Campylobacter broiler isolates, it was determined that 100% of tetracycline-resistant isolates (n = 119) harboured tet(O). Accessory tetracycline-resistance mechanisms were considered as tetracycline minimum inhibitory concentrations ranged from 4 to ≥ 64 mg/L. Primers previously reported for the detection of tet(A) in Campylobacter failed to produce an amplicon using a positive control strain (Escherichia coli K12 SK1592 containing the pBR322 plasmid) and a selection of Campylobacter isolates. Accordingly, we designed new tet(A)-targeting primers on SnapGene2.3.2 that successfully generated a 407 bp product from the positive control strain only. Further in silico analysis using BLASTn and SnapGene2.3.2 revealed that previously reported Campylobacter tet(A) sequences deposited on GenBank shared 100% homology with Campylobacter tet(O). We postulate that this gave rise to the erroneous report of a high tet(A) prevalence among a pool of Kenyan broiler Campylobacter isolates that were tested using primers designed based on these apparent tet(A) sequences. In conclusion, further work would be required to determine whether the homology between tet(A) potentially present in Campylobacter and known tet(A) genes would be sufficient to allow amplification using the primers designed in our study. Finally, the existence of tet(A) in thermophilic Campylobacter spp. remains to be demonstrated.

Human campylobacteriosis: A public health concern of global importance

Campylobacter species are among the leading cause of bacterial foodborne and waterborne infections. In addition, Campylobacter is one of the major causative agent of bacterial gastrointestinal infections and the rise in the incidence of Campylobacter infections have been reported worldwide. Also, the emergence of some Campylobacter species as one of the main causative agent of diarrhea and the propensity of these bacteria species to resist the actions of antimicrobial agents; position them as a serious threat to the public health. This paper reviews Campylobacter pathogenicity, infections, isolation and diagnosis, their reservoirs, transmission pathways, epidemiology of Campylobacter outbreaks, prevention and treatment option, antibiotics resistance and control of antibiotics use.

Antimicrobial resistance genotypes and phenotypes of Campylobacter jejuni isolated in Italy from humans, birds from wild and urban habitats, and poultry

Campylobacter jejuni, a common foodborne zoonotic pathogen, causes gastroenteritis worldwide and is increasingly resistant to antibiotics. We aimed to investigate the antimicrobial resistance (AMR) genotypes of C. jejuni isolated from humans, poultry and birds from wild and urban Italian habitats to identify correlations between phenotypic and genotypic AMR in the isolates. Altogether, 644 C. jejuni isolates from humans (51), poultry (526) and wild- and urban-habitat birds (67) were analysed. The resistance phenotypes of the isolates were determined using the microdilution method with EUCAST breakpoints, and AMR-associated genes and single nucleotide polymorphisms were obtained from a publicly available database. Antimicrobial susceptibility testing showed that C. jejuni isolates from poultry and humans were highly resistant to ciprofloxacin (85.55% and 76.47%, respectively), nalidixic acid (75.48% and 74.51%, respectively) and tetracycline (67.87% and 49.02%, respectively). Fewer isolates from the wild- and urban-habitat birds were resistant to tetracycline (19.40%), fluoroquinolones (13.43%), and quinolone and streptomycin (10.45%). We retrieved seven AMR genes (tet (O), cmeA, cmeB, cmeC, cmeR, blaOXA-61 and blaOXA-184) and gyrA-associated point mutations. Two major B-lactam genes called blaOXA-61 and blaOXA-184 were prevalent at 62.93% and 82.08% in the poultry and the other bird groups, respectively. Strong correlations between genotypic and phenotypic resistance were found for fluoroquinolones and tetracycline. Compared with the farmed chickens, the incidence of AMR in the C. jejuni isolates from the other bird groups was low, confirming that the food-production birds are much more exposed to antimicrobials. The improper and overuse of antibiotics in the human population and in animal husbandry has resulted in an increase in antibiotic-resistant infections, particularly fluoroquinolone resistant ones. Better understanding of the AMR mechanisms in C. jejuni is necessary to develop new strategies for improving AMR programs and provide the most appropriate therapies to human and veterinary populations.

Detection of efflux pump CmeABC in enrofloxacin resistant Campylobacter spp. strains isolated from broiler chickens (Gallus gallus domesticus) in the state of Rio de Janeiro, Brazil

ABSTRACT: Fowls are the main reservoirs of the highly important food-originating pathogen called Campylobacter spp. and broilers’ meat and byproducts are the main vehicles of this microorganism. Increasing of Campylobacter spp. resistant strains to fluorquinolones, an antimicrobial class often employed in poultry farming and in human medicine has become a great concern to poultry breeders. In fact, several studies evaluated increasing bacterial resistance against these antimicrobial agents. The role of CmeABC efflux system has been underscored among the resistance mechanisms in Campylobacter spp. to fluorquinolones. This study investigated the occurrence of CmeABC efflux pump in 81 and 78 enrofloxacin resistant strains of Campylobacter jejuni and C. coli respectively, isolated from broilers collected from six abattoirs situated at São José do Vale do Rio Preto/RJ poultry center and from two commercial abattoirs situated at Metropolitan Region of Rio de Janeiro, from 2013 to 2016. The resistance to enrofloxacin was assessed by agar dilution to determine minimum inhibitory concentration (MIC). The CmeABC efflux system was investigated through the detection of genes genes cmeA, cmeB and cmeC by PCR. The activity of CmeABC efflux pump was investigated in 20 strains by using the efflux pump inhibitor Phenylalanine-Arginine β-Naphthylamide (PAβN). The three genes cmeA, cmeB and cmeC were detected in 94.3% of the strains (C. jejuni = 80 and C. coli = 70), whereas the system was absent or incomplete in 5.7% of strains (C. jejuni = 1 and C. coli = 8). MIC varied between 0.5μg/ml and 64μg/ml, and 88.7% of strains were enrofloxacin resistant and 11.3% featuring intermediate resistance. The inhibition of the efflux pump by PAβN reduced the MIC to enrofloxacin up to eight times in fifteen strains (75%). These results indicate that this system is frequent and active in Campylobacter spp. Resistant strains in the presence of enrofloxacin.

Occurrence of Campylobacter jejuni and Campylobacter coli in Cattle and Sheep in Northern Spain and Changes in Antimicrobial Resistance in Two Studies 10-years Apart

A cross-sectional survey was conducted in 2014-2016 in 301 ruminant herds to estimate C. jejuni and C. coli prevalence, and investigate their susceptibility to antimicrobials. Risk of shedding C. jejuni was higher in cattle than sheep (81.2% vs. 45.2%; ORadj = 5.22, p < 0.001), whereas risk of shedding C. coli was higher in sheep than in cattle (19.1% vs. 11.3%; ORadj = 1.71, p = 0.128). Susceptibility to six antimicrobials was determined by broth microdilution using European Committee for Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off values. C. coli exhibited higher resistance (94.1%, 32/34) than C. jejuni (65.1%, 71/109), and resistance was more widespread in isolates from dairy cattle than beef cattle or sheep. Compared to results obtained 10-years earlier (2003-2005) in a similar survey, an increase in fluoroquinolone-resistance was observed in C. jejuni from beef cattle (32.0% to 61.9%; OR = 3.45, p = 0.020), and a decrease in tetracycline-resistance in C. jejuni from dairy cattle (75.0% to 43.2%; OR = 0.25, p = 0.026). Resistance to macrolides remained stable at low rates and restricted to C. coli from dairy cattle, with all macrolide-resistant C. coli showing a pattern of pan-resistance. Presence of the single nucleotide polymorphisms (SNPs) associated to quinolone and macrolide resistance was confirmed in all phenotypically resistant isolates. The increase in fluoroquinolone resistance is worrisome but susceptibility to macrolides is reassuring.

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.

Characterization and Phylogenetic Analysis of Campylobacter Species Isolated from Paediatric Stool and Water Samples in the Northwest Province, South Africa

Antibiotic-resistant Campylobacter could adversely affect treatment outcomes, especially in children. We investigated the antibiotic susceptibility profiles, virulence potentials and genetic relatedness of Campylobacter spp. from paediatric and water samples in the North West Province, South Africa. Overall, 237 human and 20 water isolates were identified using culture and real-time polymerase chain reaction (PCR). The antibiotic susceptibility profiles were determined using the disk diffusion method. Gradient strips were used to determine the minimum inhibitory concentration of each antibiotic. Antibiotic resistance (gryA, tetO and 23S rRNA 2075G and 2074C) and virulence (cadF and ciaB) genes were also investigated using PCR. A phylogenetic tree to ascertain the clonality between water and clinical isolates was constructed using MEGA 7. Overall, 95% (water) and 64.7% (human) of the isolates were resistant to at least one antibiotic tested. The highest resistance was against clarithromycin (95%) for water and ampicillin (60.7%) for human isolates. The 23S rRNA 2075G/2074C mutation was the most expressed resistance gene. Phylogenetic reconstruction revealed eight intermixed clades within water and human Campylobacter isolates. This study suggests the possible circulation of potentially pathogenic antibiotic-resistant Campylobacter in the Northwest Province, South Africa with drinking water being a possible vector for disease transmission in this area.

Overlap of Antibiotic Resistant Campylobacter jejuni MLST Genotypes Isolated From Humans, Broiler Products, Dairy Cattle and Wild Birds in Lithuania

Antimicrobial resistance was determined for 341 thermophilic Campylobacter jejuni isolates obtained from human clinical cases (n = 101), broiler products (n = 98), dairy cattle (n = 41) and wild birds (n = 101) with known multilocus sequence types (MLST) in Lithuania. The minimum inhibitory concentration (MIC) values for ciprofloxacin, tetracycline, gentamicin, ceftriaxone and erythromycin were determined with the agar dilution method. MIC values were compared with MLST types to find possible associations among isolation source, sequence type and resistance to antibiotics. The proportions of resistant strains were 94.2% (human), 95% (wild birds), 100% (broiler products) and 100% (dairy cattle) for one of the tested antibiotics. Most frequently, resistance to ciprofloxacin was observed (91.5%), followed by ceftriaxone with 60.4%, and tetracycline (37.8%). However only three C. jejuni strains were resistant to erythromycin (0.9%) and all tested thermophilic Campylobacter strains were sensitive to gentamicin. Most of the examined C. jejuni isolates (80.6%) showed resistance to at least one of three profiles: CIP+AXO (28.1%), TET+CIP+AXO (26.7%) and CIP (25.8%). Statistically significant differences in resistance to tetracycline were found between C. jejuni strains obtained from cattle (85.4%) and broiler products (64.3%) (P < 0.05). The majority (87.1%) of the tested strains from wild birds were resistant to ciprofloxacin (P < 0.05). The results showed that strains of novel ST's showed significantly lower resistance to ceftriaxone (P < 0.05). The ST-21 (CC21) (78.8%) was identified with significantly higher multidrug resistance relatively to other tested ST's in this study. Our results emphasize the high antimicrobial resistance of phylogenetically diverse C. jejuni strains isolated from different sources including specific genotypes of wild bird's strains in Lithuania. The results support the opinion that not only broiler products but cattle and wild birds may be a reservoir of resistant C. jejuni and stipulate a risk of spread or resistant bacteria. There is increasing need for broad surveillance and control measures to track changes and pathways of antimicrobial resistance of C. jejuni in epidemiologically distinct populations.

Whole-genome comparative analysis of Campylobacter jejuni strains isolated from patients with diarrhea in northeastern Poland

BACKGROUND

Campylobacter jejuni is the leading cause of bacterial gastroenteritis (campylobacteriosis) in humans worldwide, and the most frequent pathogen associated with Guillain-Barré syndrome (GBS) and Miller-Fisher syndrome (MFS). The study was designed in order to assess similarities between genomes of Campylobacter jejuni strains, isolated from children suffering from acute diarrhea in northeastern Poland, in comparison to C. jejuni genomes stored in public databases. The analysis involved phylogeny, resistome and virulome. In addition, the Campylobacter PubMLST database was used to estimate the prevalence of the analyzed C. jejuni sequence type (STs) in other countries.

RESULTS

Campylobacter jejuni ST50, ST257 and ST51 represented 5.3%, 4.5% and 2.2% of the PubMLST records, respectively. Overall, strains representing the STs showed common resistance to tetracyclines (51.3%) and fluoroquinolones (31.8%), mediated through the tetO gene (98.2%) and point mutation (T86I) in the gyrA gene (100%). However, the latter was present in all our isolates. The major differences in virulence patterns concerned serotypes, lipooligosaccharide (LOS) classes and certain clinically relevant genes.

CONCLUSIONS

Campylobacter jejuni ST50, ST51 and ST257 are among the top ten of STs isolated in Europe. WGS revealed diversity of serotypes and LOS classes in ST50 strains, that deserves further clinical and epidemiological investigations as it might be related to a risk of post-infectious neurological sequels such as Guillain-Barré syndrome. Additionally, the results implicate lower pathogenic potential and distinct transmission chains or reservoirs for C. jejuni ST51 isolates responsible for campylobacteriosis in northeastern Poland.

Quinolone and Macrolide-Resistant Campylobacter jejuni in Pediatric Gastroenteritis Patients from Central Iran

Aims: To determine the prevalence and the antibiotic resistance patterns of Campylobacter jejuni isolated from pediatric diarrhea patients in central Iran. Materials and Methods: Stool specimens (n = 230) were investigated using a modified Gram stain, two specific culture media, and C. jejuni-specific PCR. Antibiotic resistance profiles and relevant resistance genes were determined. Genetic relationships among a selection of the isolates were studied by Fla typing. Results: Out of the 230 diarrhea samples, 48 (20.8%) cases of C. jejuni were identified using modified Gram stain, 45 (19.5%) using the culture media, and 76 (33%) cases were identified using PCR. The highest antibiotic resistance rates were observed in 37 (82.2%) strains against tetracycline, in 32 (71.1%) against ciprofloxacin, and in 31 (68.8%) against erythromycin. Twenty (44.4%) isolates were resistant to ciprofloxacin and erythromycin simultaneously. Genotypic investigations found 36 (97.3%) strains carrying the tet (o) gene, 31 (96.8%) harboring the cmeB gene, 22 (68.7%) strains with the gyrA6 gene, 20 (64.5%) strains containing a 23S rRNA mutation, and 21 (65.6%) strains with the qnrS gene. Fla typing of a random subset of 14 strains revealed 11 different types showing the genomic diversity of the isolates. Strains sharing the same Fla type could be easily distinguished by their resistance gene profile. Conclusions: This is the first study to demonstrate that genetically diverse quinolone-macrolide-resistant C. jejuni is an important cause of gastroenteritis in children from central Iran. Pediatricians should consider these resistance features once the antibiotic prescription is necessary for prevention of possible complications, especially in those under 5 years of age. Of note, most cases of Campylobacter diarrhea are self-limiting and antibiotics should only be prescribed in those cases where severe complications evolve.

Novel narrow spectrum benzyl thiophene sulfonamide derivatives to control Campylobacter

Campylobacter is a leading cause of bacterial foodborne gastroenteritis worldwide, and poultry are a major source of human campylobacteriosis. The control of Campylobacter from farm to fork is challenging due to emergence of microbial resistance and lack of effective control methods. We identified a benzyl thiophene sulfonamide based small molecule (compound 1) with a minimal inhibitory concentration (MIC) of 100 μM against Campylobacter jejuni 81-176 and Campylobacter coli ATCC33559, good drug-like properties, and low toxicity on eukaryotic cells. Compound 1 was used as a lead for the preparation of 13 analogues. Two analogues, compounds 4 and 8 (TH-4 and TH-8), were identified with better antimicrobial properties than compound 1. TH-4 and TH-8 had a MIC of 12.5 μM and 25 μM for C. coli and 50 μM and 100 μM for C. jejuni, respectively. Cytological studies revealed that both compounds affected C. jejuni envelope integrity. Further, both compounds had no effect on other foodborne pathogens. TH-4 and TH-8 had a minimal impact on the chicken cecal microbiota and were not toxic to colon epithelial cells and chicken macrophages, and red blood cells at 200 µM. Further, TH-4 and TH-8 reduced the Campylobacter load in chicken ceca (up to 2-log reduction) when infected chickens were orally treated for 5 days with 0.254 mg kg^-1; as well as against internalized Campylobacter in Caco-2 cells at 12.5 µM and higher. Our study identified two novel specific and safe benzyl thiophene sulfonamide derivatives having potential for control of Campylobacter in chickens and humans.

Antibiotic Resistance of Campylobacter Species in a Pediatric Cohort Study

The objective of this study was to determine the phenotypic patterns of antibiotic resistance and the epidemiology of drug-resistant Campylobacter spp. from a low-resource setting. A birth cohort of 303 patients was followed until 5 years of age. Stool samples from asymptomatic children (n = 10,008) and those with diarrhea (n = 3,175) were cultured for Campylobacter Disk diffusion for ciprofloxacin (CIP), nalidixic acid (NAL), erythromycin (ERY), azithromycin (AZM), tetracycline (TE), gentamicin (GM), ampicillin (AMP), amoxicillin and clavulanic acid (AMC), ceftriaxone (CRO), chloramphenicol (C), and trimethoprim-sulfamethoxazole (TMS) was determined. Antibiotic resistances in Campylobacter jejuni and non-C. jejuni isolates from surveillance and diarrhea samples were compared, and the association between personal macrolide exposure and subsequent occurrence of a macrolide-resistant Campylobacter spp. was assessed. Of 917 Campylobacter isolates, 77.4% of C. jejuni isolates and 79.8% of non-C. jejuni isolates were resistant to ciprofloxacin, while 4.9% of C. jejuni isolates and 24.8% of non-C. jejuni isolates were not susceptible to azithromycin. Of the 303 children, 33.1% had been diagnosed with a Campylobacter strain nonsusceptible to both azithromycin and ciprofloxacin. Personal macrolide exposure did not affect the risk of macrolide-resistant Campylobacter Amoxicillin and clavulanic acid (94.0%) was one of the antibiotics with the highest rates of susceptibility. There is a high incidence of quinolone- and macrolide-resistant Campylobacter infections in infants under 24 months of age. Given the lack of association between personal exposure to macrolides and a subsequent Campylobacter infection resistant to macrolides, there is a need to evaluate the source of multidrug-resistant (MDR) Campylobacter This study provides compelling evidence to propose amoxicillin/clavulanic acid as a treatment for campylobacteriosis.

Prevalence, antimicrobial resistance, and virulence-associated genes of Campylobacter isolates from raw chicken meat in Shiraz, Iran

BACKGROUND

Campylobacter is recognized as a major cause of foodborne gastroenteritis in humans in many countries and may be transferred from animals to humans. The consumption of chicken meat is identified as a major cause of Campylobacter infection in humans.

AIMS

To find out the contamination rate of chicken meat with Campylobacter, the antimicrobial resistance (AMR) pattern, and the virulence-associated genes of the isolates.

METHODS

Ninety packed chicken meat from 7 main poultry slaughterhouses in Shiraz were analyzed for Campylobacter spp. isolation through microbiological methods. Specific primers were used for the identification of the Campylobacter isolates on species level by polymerase chain reaction (PCR). Antibiotic resistant profiles were determined using the disc diffusion method based on Clinical and Laboratory Standards Institute (CLSI) standards. All the isolates were screened for 7 virulence-associated genes, namely cdtA, cdtB, cdtC, cadF, pldA, cgtB, and virB11 by PCR.

RESULTS

Out of 90 chicken meats, 26 (28.9%) Campylobacter spp. have been isolated. Resistance to ciprofloxacin (CIP), nalidixic acid (NA), and cefixime (CFM) was observed in all the isolates. Resistance to trimethoprim/sulfamethoxazole (SXT), tetracycline (TET), ampicillin (AMP), and chloramphenicol (CHO) was 80.8%, 88.5%, 76.9%, and 30.8%, respectively. Multidrug resistance (MDR) phenotype was observed in 80.8% of the Campylobacter isolates. All the isolates were positive for cdtA, cdtB, cdtC, and cadF genes. pldA and cgtB were detected in 65.4% and 15.4% of the isolates, respectively.

CONCLUSION

In this study, the presence of several virulence genes and an alarming level of MDR in Campylobacter spp. isolates were reported. Particularly, resistance to CIP and TET should be highlighted, since both are key drugs for the treatment of human campylobacteriosis.

Virulence typing and antibiotic susceptibility profiling of thermophilic Campylobacters isolated from poultry, animal, and human species

Background and Aim:

Campylobacteriosis finds its place among the four important global foodborne illnesses. The disease, though self-limiting, needs antibacterial therapy in extraintestinal complications. Therefore, the present study was designed to estimate the prevalence of thermophilic Campylobacters in poultry, animals, and humans of the Kumaon region of Uttarakhand.

Materials and Methods:

A total of 609 samples comprising of poultry ceca (n=116), poultry droppings (n=203), and feces of pigs (n=71), cattle (n=61), sheep (n=19), goat (n=17), human beings (n=88), and laboratory animals (n=34) (rats, rabbits, and guinea pigs) were collected. The thermophilic Campylobacters, Campylobacter jejuni and Campylobacter coli were confirmed using multiplex polymerase chain reaction. The isolates were also screened for the presence of virulence genes, and their antibiotic susceptibility testing was done against eight antibiotics.

Results:

An overall prevalence of 6.24% was revealed with highest from poultry ceca (15.52%), followed by poultry droppings (5.91%), cattle feces (4.92%), human stools (3.40%), and pig feces (2.82%). The virulence genes, namely cadF, flaA, virB11, and pldA, were present in 38 (100%), 37 (97.37%), 7 (18.42%), and 14 (36.84%) isolates, respectively. All the isolates were resistant to nalidixic acid, while all were sensitive to erythromycin and co-trimoxazole.

Conclusion:

It was concluded that the animals and humans in the region harbored the thermophilic Campylobacters which may contribute to the human illness. Resistance shown among the isolates may complicate the antimicrobial therapy.

The CRISPR-cas system promotes antimicrobial resistance in Campylobacter jejuni

AIM

The purpose of current study is to find out relationship between cas9 gene and antimicrobial resistance in Campylobacter jejuni NCTC11168.

MATERIALS & METHODS

The involvement of the cas9 gene in antimicrobial resistance of C. jejuni was determined by assessment of minimum inhibitory concentration, clustered regularly interspaced short palindromic repeats (CRISPR)-cas gene expression in standard strains, in vitro resistance development and transcriptome analysis of a cas9 deletion mutant and wild strains.

RESULTS

Increased expression of CRISPR-related genes was observed in standard strains. We also observed that Δcas9 mutant strain is more sensitive to antibiotics than its wild strain. Transcriptome analysis revealed that cas9 gene regulate several genes to promote antimicrobial resistance in C. jejuni.

CONCLUSION

CRISPR-cas system plays role in the enhancement of antimicrobial resistance in C. jejuni.

Antimicrobial Resistance in Campylobacter spp

Campylobacter is a major foodborne pathogen and has become increasingly resistant to clinically important antimicrobials. To cope with the selection pressure from antimicrobial use in both veterinary and human medicine, Campylobacter has developed multiple mechanisms for antibiotic resistance, including modification or mutation of antimicrobial targets, modification or inactivation of antibiotics, and reduced drug accumulation by drug efflux pumps. Some of these mechanisms confer resistance to a specific class of antimicrobials, while others give rise to multidrug resistance. Notably, new antibiotic resistance mechanisms continuously emerge in Campylobacter, and some examples include the recently discovered multidrug resistance genomic islands harboring multiple genes involved in the resistance to aminoglycosides and macrolides, a novel Cfr(C) conferring resistance to phenicols and other drugs, and a potent multidrug efflux pump CmeABC variant (RE-CmeABC) that shows a significantly enhanced function in multidrug resistance and is associated with exceedingly high-level resistance to fluoroquinolones. These newly emerged resistance mechanisms are horizontally transferable and greatly facilitate the adaptation of Campylobacter in the food-producing environments where antibiotics are frequently used. In this article, we will discuss how Campylobacter resists the action of various classes of antimicrobials, with an emphasis on newly discovered mechanisms.

ant(6)-I Genes Encoding Aminoglycoside O-Nucleotidyltransferases Are Widely Spread Among Streptomycin Resistant Strains of Campylobacter jejuni and Campylobacter coli

Thermotolerant Campylobacter species C. jejuni and C. coli are actually recognized as the major bacterial agent responsible for food-transmitted gastroenteritis. The most effective antimicrobials against Campylobacter are macrolides and some, but not all aminoglycosides. Among these, susceptibility to streptomycin is reduced by mutations in the ribosomal RPSL protein or by expression of ANT(6)-I aminoglycoside O-nucleotidyltransferases. The presence of streptomycin resistance genes was evaluated among streptomycin-resistant Campylobacter isolated from humans and animals by using PCR with degenerated primers devised to distinguish ant(6)-Ia, ant(6)-Ib and other ant-like genes. Genes encoding ANT(6)-I enzymes were found in all possible combinations with a major fraction of the isolates carrying a previously described ant-like gene, distantly related and belonging to the new ant(6)-I sub-family ant(6)-Ie. Among Campylobacter isolates, ant(6)-Ie was uniquely found functional in C. coli, as shown by gene transfer and phenotype expression in Escherichia coli, unlike detected coding sequences in C. jejuni that were truncated by an internal frame shift associated to RPSL mutations in streptomycin resistant strains. The genetic relationships of C. coli isolates with ANT(6)-Ie revealed one cluster of strains presented in bovine and humans, suggesting a circulation pathway of Campylobacter strains by consuming contaminated calf meat by bacteria expressing this streptomycin resistance element.

Whole-Genome Sequence Analysis of Multidrug-Resistant Campylobacter Isolates: a Focus on Aminoglycoside Resistance Determinants

A whole-genome sequencing (WGS) approach was conducted in order to identify the molecular determinants associated with antimicrobial resistance in 12 multidrug-resistant Campylobacter jejuni and Campylobacter coli isolates, with a focus on aminoglycoside resistance determinants. Two variants of a new aminoglycoside phosphotransferase gene [aph(2″)-Ii1 and aph(2″)-Ii2 ] putatively associated with gentamicin resistance were found. In addition, the following new genes were identified for the first time in Campylobacter: a lincosamide nucleotidyltransferase gene [lnu(G)], likely associated with lincomycin resistance, and two resistance enzyme genes (spw and apmA) similar to those found in Staphylococcus aureus, which may confer spectinomycin and gentamicin resistance, respectively. A C1192T mutation of the 16S rRNA gene that may be involved in spectinomycin resistance was also found in a C. coli isolate. Genes identified in the present study were located either on the bacterial chromosome or on plasmids that could be transferred naturally. Their role in aminoglycoside resistance remains to be supported by genetic studies. Regarding the other antimicrobial agents studied, i.e., ampicillin, ciprofloxacin, erythromycin, and tetracycline, a perfect correlation between antimicrobial phenotypes and genotypes was found. Overall, our data suggest that WGS analysis is a powerful tool for identifying resistance determinants in Campylobacter and can disclose the full genetic elements associated with resistance, including antimicrobial compounds not tested routinely in antimicrobial susceptibility testing.

A Review of the Effect of Management Practices on Campylobacter Prevalence in Poultry Farms

Poultry is frequently associated with campylobacteriosis in humans, with Campylobacter jejuni being the most usual Campylobacter associated with disease in humans. Far-reaching research on Campylobacter was undertaken over the past two decades. This has resulted in interventions being put in place on farms and in processing plants. Despite these interventions, coupled with increased media coverage to educate the consumer on Campylobacter prevalence and campylobacteriosis, human health incidents are still high. Recent research is now shifting toward further understanding of the microorganisms to challenge interventions in place and to look at further and more relevant interventions for the reduction in human incidents. Farm practices play a key role in the control of colonization within poultry houses and among flocks. Prevalence at the farm level can be up to 100% and time of colonization may vary widely between flocks. Considerable research has been performed to understand how farm management and animal health practices can affect colonization on farms. This review will focus on farm practices to date as a baseline for future interventions as the microorganism becomes better understood. Further research is required to understand the chicken microbiome and factors influencing vertical transmission. The persistence of Campylobacter in animal and environmental reservoirs within and around farms requires further investigation to tailor farm practices toward preventing such reservoirs. IMPLICATIONS  This review gives an overview of farm practices and their effect on Campylobacter prevalence in poultry. Various elements of farm practices have been captured in this review.

Human Campylobacteriosis in Italy: Emergence of Multi-Drug Resistance to Ciprofloxacin, Tetracycline, and Erythromycin

Campylobacter spp. is one of the main cause of bacterial gastroenteritis in the world. The increase of antibiotic resistance in this species is a threat to public health. A Campylobacter spp. surveillance study was performed in Italy in the 2013-2016 period by the Enter-Net Italia network. The most prevalent Campylobacter species identified causing gastroenteritis was Campylobacter jejuni (73.4%) and 45% of all the annual cases of campylobacteriosis were reported in the summer period. High rates of ciprofloxacin and tetracycline resistance in Campylobacter spp. have been observed. An increasing percentage of Campylobacter coli strains simultaneously resistant to ciprofloxacin, tetracycline and erythromycin has been found. Molecular mechanisms of resistance have been investigated and the role of efflux pumps evaluated. Antibiotic resistance in Campylobacter spp. is an increasing serious threat that requires coordinated action to minimize the emergence and spread of antimicrobial resistant strains from animals to humans throughout the food chain.

Genetic and Antibiotic Resistance Characteristics of Campylobacter jejuni Isolated from Diarrheal Patients, Poultry and Cattle in Shenzhen

OBJECTIVE

To investigate genetic and antibiotic resistance characteristics of Campylobacter jejuni (C. jejuni) isolated from Shenzhen.

METHODS

Multilocs sequence typing and agar dilution methods were used to define the genotype and antibiotic resistance of C. jejuni, respectively.

RESULTS

In total, 126 C. jejuni strains were isolated. The prevalence of C. jejuni was 5.3% in diarrheal patients. The prevalence in poultry meat (36.5%) was higher than that in cattle meat (1.1%). However, the prevalence in poultry cloacal swabs (27.0%) was lower than that in cattle stool (57.3%). Sixty-two sequence types were obtained, among which 27 of the STs and 10 alleles were previously unreported. The most frequently observed clonal complexes were ST 21 (11.9%), ST-22 (10.3%), and ST-403 (7.1%). ST-21, ST-45, ST-354, ST-403, and ST-443 complexes overlapped between isolates from patients and cattle, whereas ST-45 and ST-574 complexes overlapped between isolates from patients and poultry. All C. jejuni were resistant to at least one antibiotic. The highest resistance rate was toward ciprofloxacin (89.7%), followed by tetracycline (74.6%), and nalidixic acid (69.0%).

CONCLUSION

This is the first report of the genotypes and antibiotic resistance of C. jejuni in Shenzhen. Overlapping clonal complexes were found between isolates from patients and cattle, and between patients and poultry.

Molecular Identification of Multidrug-Resistant Campylobacter Species From Diarrheal Patients and Poultry Meat in Shanghai, China

Emerging resistance to the antimicrobial agents of choice for treatment of thermophilic Campylobacter infections is becoming a serious threat to public health. In this study, 548 Campylobacter (372 C. jejuni and 176 C. coli) isolates from diarrheal patients and poultry meat were subjected for antibiotic susceptibility analysis to ciprofloxacin, tetracycline, gentamicin, erythromycin and clindamycin. Among them, 151 Campylobacter (32 C. jejuni and 119 C. coli) were identified as multidrug resistant isolates. PFGE analysis was performed on the 151 multidrug resistant isolates to determine their genetic relatedness, and 103 PFGE genotypes were determined. Some isolates from both human and chicken belonged to identical genotypes, indicating these clones might be able to spread between human and chicken. Antibiotic resistant genes of the 151 isolates were identified. The numbers of isolates carried tet (O), aadE, ermB, and aadE-sat4-aphA were 148 (98%), 89 (58.9%), 31 (20.5%), and 10 (6.6%), respectively. Almost all (n = 150, 99.3%) had gyrA mutation at codon 86. And the 23s rRNA A2075G point mutation was found in 56 (37.1%) isolates. Gene mutations at the cmeR-cmeABC intergenic region may lead to the activation of CmeABC multidrug efflux pump, and in this study novel sequence types of the intergenic region were identified in both C. jejuni and C. coli. This study determined the genetic prerequisites for antibiotic resistance of multidrug resistant Campylobacter isolates from diarrheal patients and poultry meat in Shanghai, China.

Typing of Campylobacter jejuni isolated from poultry on the basis of flaA-RFLP by various restriction enzymes

RFLP analysis of the flagellin (flaA) gene was compared using three different restriction endonucleases i.e DdeI, HinfI and DpnII to determine the genetic diversity among 43 Campylobacter jejuni isolates of poultry origin from the same geographical area. flaA gene was amplified in all the isolates and RFLP analysis showed variations. Dde-based RFLP was found most efficient in discriminating C. jejuni isolates by generating 15 different Dde-RFLP patterns with discriminatory index (D.I) of 0.9258 whereas DpnII produced seven Dpn-RFLP patterns (D.I .= 0.8427). While HinfI enzyme produced only six Hinf-RFLP patterns (D.I .= 0.6977). The discrimination of Dpn-RFLP was comparable to discrimination given by Dde-RFLP analysis, which is generally used to study flaA gene RFLP.

Campylobacter in the Food Chain

Currently Campylobacter is the most commonly reported zoonosis in developed and developing countries. In the European Union, the number of reported confirmed cases of human campylobacteriosis was 246,307 in 2016, which represents 66.3 cases per 100,000 population. The genus Campylobacter includes 31 species with 10 subspecies. Within the genus Campylobacter, C. jejuni subsp. jejuni and C. coli are most frequently associated with human illness. Mainly, the infection is sporadic and self-limiting, although some cases of outbreaks have been also reported and some complications such as Guillain-Barré syndrome might appear sporadically. Although campylobacters are fastidious microaerophilic, unable to multiply outside the host and generally very sensitive, they can adapt and survive in the environment, exhibiting aerotolerance and resistance to starvation. Many mechanisms are involved in this, including pathogenicity, biofilm formation, and antibiotic resistant pathways. This chapter reviews the sources, transmission routes, the mechanisms, and strategies used by Campylobacter to persist in the whole food chain, from farm to fork. Additionally, different strategies are recommended for application along the poultry food chain to avoid the public health risk associated with this pathogen.

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review

Zoonoses are diseases transmitted from animals to humans, posing a great threat to the health and life of people all over the world. According to WHO estimations, 600 million cases of diseases caused by contaminated food were noted in 2010, including almost 350 million caused by pathogenic bacteria. Campylobacter, Salmonella, as well as Yersinia enterocolitica and Listeria monocytogenes may dwell in livestock (poultry, cattle, and swine) but are also found in wild animals, pets, fish, and rodents. Animals, often being asymptomatic carriers of pathogens, excrete them with faeces, thus delivering them to the environment. Therefore, pathogens may invade new individuals, as well as reside on vegetables and fruits. Pathogenic bacteria also penetrate food production areas and may remain there in the form of a biofilm covering the surfaces of machines and equipment. A common occurrence of microbes in food products, as well as their improper or careless processing, leads to common poisonings. Symptoms of foodborne infections may be mild, sometimes flu-like, but they also may be accompanied by severe complications, some even fatal. The aim of the paper is to summarize and provide information on campylobacteriosis, salmonellosis, yersiniosis, and listeriosis and the aetiological factors of those diseases, along with the general characteristics of pathogens, virulence factors, and reservoirs.

Antibacterial Activity of Glutathione-Stabilized Silver Nanoparticles Against Campylobacter Multidrug-Resistant Strains

Campylobacter is the leading cause of bacterial diarrheal disease worldwide. Although most episodes of campylobacteriosis are self-limiting, antibiotic treatment is usually needed in patients with serious enteritis, and especially in childrens or the elderly. In the last years, antibiotic resistance in Campylobacter has become a major public health concern and a great interest exists in developing new antimicrobial strategies for reducing the impact of this food-borne pathogen on human health. Among them, the use of silver nanoparticles as antibacterial agents has taken on increased importance in the field of medicine. The aim of the present study was to evaluate the antimicrobial effectiveness of glutathione-stabilized silver nanoparticles (GSH-Ag NPs) against multidrug resistant (MDR) Campylobacter strains isolated from the chicken food chain (FC) and clinical patients (C). The results obtained showed that GSH-Ag NPs were highly effective against all MDR Campylobacter strains tested. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were in a range from 4.92 to 39.4 μg/mL and 9.85 to 39.4 μg/mL, respectively. Cytotoxicity assays were also assessed using human intestinal HT-29, Caco-2, and CCD-18 epithelial cells. Exposure of GSH-Ag NPs to intestinal cells showed a dose-dependent cytotoxic effect in all cell lines between 9.85 and 39.4 μg/mL. More than 60% of the tested Campylobacter strains were susceptible to GSH-Ag NPs concentrations ≤ 9.85 μg/mL, suggesting that practical inhibitory levels could be reached at low GSH-Ag NPs concentrations. Further works are needed with the purpose to evaluate the practical implications of the toxicity studies and to know more about other attributes linked to the biological compatibility. This behavior makes GSH-Ag NPs as a promising tool for the design of novel antibacterial agents for controlling Campylobacter.

Prevalence of Genetic Determinants and Phenotypic Resistance to Ciprofloxacin in Campylobacter jejuni from Lithuania

Recently, the number of reports on isolation of ciprofloxacin resistant Campylobacter jejuni has increased worldwide. The aim of this study was to determine the prevalence of resistance to ciprofloxacin and its genetic determinants among C. jejuni isolated from humans (n = 100), poultry products (n = 96) and wild birds (n = 96) in Lithuania. 91.4% of the C. jejuni isolates were phenotypically resistant to ciprofloxacin. DNA sequence analyses of the gyrA gene from 292 isolates revealed that a change in amino acid sequence, Thr86Ile, was the main substition conferring resistance to ciprofloxacin. This change was significantly associated with isolates from poultry products (P < 0.05) and humans (P < 0.05). A total of 26.7% of C. jejuni isolates from human (n = 47), poultry products (n = 30) and wild bird (n = 1), had a mutation from Ser at position 22, and six had an additional mutation from Ala at position 39. Eight isolates from poultry and two isolates from human, corresponding to 67.0% of isolates with MICs ≥128 μg/ml, showed missense mutations Thr86Ile (ACA → ATA) and Ser22Gly (AGT → GGT) together, whereas isolates without these mutations showed lower MIC values (from 4 to 64 μg/ml). Two hundred forty-five C. jejuni isolates showed one or more silent mutations, and 32.4% of examined isolates possessed six silent mutations. In addition to the ciprofloxacin resistant isolates harboring only Thr86Ile point mutation (110 isolates), the current study identified resistant isolates (n = 101) harboring additional point mutations (Ser22Gly, Ala39Ser, Arg48Lys, Thr85Ala Ala122Ser, Glu136Asp, Vall49Ile), and strains (n = 57) having only Glu136Asp point mutation. The study highlight the potential public health problem with elevated ciprofloxacin resistance in Campylobacters from poultry meat, wild birds and humans, and the need for extensive surveillance enabling to follow changes of antimicrobial resistance development in this species.

Arcobacter butzleri Ciprofloxacin Resistance: Point Mutations in DNA Gyrase A and Role on Fitness Cost

Arcobacter butzleri is a widely distributed emerging pathogen resistant to various classes of antimicrobial agents, namely fluoroquinolones. A. butzleri resistance to fluoroquinolones is conferred by point mutations at the antibiotic target. The aim of this study was to evaluate mutations at gyrA associated with ciprofloxacin resistance and evaluate whether acquisition of resistance impacts on fitness and stress tolerance of A. butzleri. A. butzleri ciprofloxacin mutants were generated by laboratory induction. Identification of mutations associated with ciprofloxacin resistance was performed by gyrA sequencing. Growth kinetics, cost of fitness, biofilm formation ability, and stress tolerance were assessed. Two amino acid substitutions in the quinolone resistance-determining region of GyrA were identified in the mutant strains, one previously described (Thr-85-Ile) and a new substitution (Asp-89-Tyr). No differences in growth kinetics were recorded between parental and mutant strains; however, fitness cost was variable, according to the genetic background of the strains, and independently of ciprofloxacin resistance. Overall, the ciprofloxacin resistance development did not significantly affect stress tolerance, motility, or biofilm-forming ability. In conclusion, acquisition of ciprofloxacin resistance in A. butzleri is associated with mutations in gyrA and is likely well compensated, with cost of fitness reflecting the diversity in genetic background of this bacterium.

Antimicrobial Resistance in Campylobacter Species: Mechanisms and Genomic Epidemiology

The Campylobacter genus is a large and diverse group of Gram-negative bacteria that are known to colonize humans and other mammals, birds, reptiles, and shellfish. While it is now recognized that several emerging Campylobacter species can be associated with human disease, two species, C. jejuni and C. coli, are responsible for the vast majority of bacterial gastroenteritis in humans worldwide. Infection with C. jejuni, in particular, has also been associated with a number of extragastrointestinal manifestations and autoimmune conditions, most notably Guillain-Barré syndrome. The antimicrobial drugs of choice for the treatment of severe Campylobacter infection include macrolides, such as erythromycin, clarithromycin, or azithromycin. Fluoroquinolones, such as ciprofloxacin, are also commonly used for empirical treatment of undiagnosed diarrheal disease. However, resistance to these and other classes of antimicrobial drugs is increasing and is a major public health problem. The US Centers for Disease Control and Prevention estimates that over 300,000 infections per year are caused by drug-resistant Campylobacter. In this chapter, we discuss the taxonomy of the Campylobacter genus, the clinical and global epidemiological aspects of Campylobacter infection, with an emphasis on C. jejuni and C. coli, and issues related to the treatment of infection and antimicrobial resistance mechanisms. We further discuss the use of next-generation sequencing for the detection and surveillance of antimicrobial resistance genes.

Trends in fluoroquinolone resistance in Campylobacter

Members of the genus Campylobacter remain a leading cause of bacterial gastroenteritis worldwide. Infection is usually self-limiting but in severe cases may require antibiotic treatment. In a recent statement by the World Health Organization (WHO) Campylobacter was named as one of the 12 bacteria that pose the greatest threat to human health because they are resistant to antibiotics. In this mini review we describe recent trends in fluoroquinolone (FQ) (particularly ciprofloxacin) resistance in strains of members of the genus Campylobacter isolated from livestock and clinical samples from several countries. Using evidence from phenotyping surveys and putative resistance prediction from DNA sequence data, we discuss the acquisition and spread of FQ resistance and the role of horizontal gene transfer and describe trends in FQ-resistance in samples from livestock and clinical cases. This review emphasises that FQ resistance remains common among isolates of members of the genus Campylobacter from various sources.

Structural and Functional Basis for Targeting Campylobacter jejuni Agmatine Deiminase To Overcome Antibiotic Resistance

Campylobacter jejuni is the most common bacterial cause of gastroenteritis and a major contributor to infant mortality in the developing world. The increasing incidence of antibiotic-resistant C. jejuni only adds to the urgency to develop effective therapies. Because of the essential role that polyamines play, particularly in protection from oxidative stress, enzymes involved in the biosynthesis of these metabolites are emerging as promising antibiotic targets. The recent description of an alternative pathway for polyamine synthesis, distinct from that in human cells, in C. jejuni suggests this pathway could be a target for novel therapies. To that end, we determined X-ray crystal structures of C. jejuni agmatine deiminase (CjADI) and demonstrated that loss of CjADI function contributes to antibiotic sensitivity, likely because of polyamine starvation. The structures provide details of key molecular features of the active site of this protein. Comparison of the unliganded structure (2.1 Å resolution) to that of the CjADI-agmatine complex (2.5 Å) reveals significant structural rearrangements that occur upon substrate binding. The shift of two helical regions of the protein and a large conformational change in a loop near the active site generate a narrow binding pocket around the bound substrate. This change optimally positions the substrate for catalysis. In addition, kinetic analysis of this enzyme demonstrates that CjADI is an iminohydrolase that effectively deiminates agmatine. Our data suggest that C. jejuni agmatine deiminase is a potentially important target for combatting antibiotic resistance, and these results provide a valuable framework for guiding future drug development.

Class 1 integrons and plasmid-mediated multiple resistance genes of the Campylobacter species from pediatric patient of a university hospital in Taiwan

Background

The Campylobacter species usually causes infection between humans and livestock interaction via livestock breeding. The studies of the Campylobacter species thus far in all clinical isolates were to show the many kinds of antibiotic phenomenon that were produced. Their integrons cause the induction of antibiotic resistance between bacterial species in the Campylobacter species.

Results

The bacterial strains from the diarrhea of pediatric patient which isolated by China Medical University Hospital storage bank. These isolates were identified by MALDI-TOF mass spectrometry. The anti-microbial susceptibility test showed that Campylobacter species resistant to cefepime, streptomycin, tobramycin and trimethoprim/sulfamethoxazole (all C. jejuni and C. coli isolates), ampicillin (89% of C. jejuni; 75% of C. coli), cefotaxime (78% of C. jejuni; 100% of C. coli), nalidixic acid (78% of C. jejuni; 100% of C. coli), tetracycline (89% of C. jejuni; 25% C. coli), ciprofloxacin (67% of C. jejuni; 50% C. coli), kanamycin (33% of C. jejuni; 75% C. coli) and the C. fetus isolate resisted to ampicillin, cefotaxime, nalidixic acid, tetracycline, ciprofloxacin, kanamycin by disc-diffusion method. The effect for ciprofloxacin and tetracycline of the Campylobacter species was tested using an E-test. The tet, erm, and integron genes were detected by PCR assay. According to the sequencing analysis (type I: dfr12-gcuF-aadA2 genes and type II: dfrA7 gene), the cassette type was identified. The most common gene cassette type (type I: 9 C. jejuni and 2 C. coli isolates; type II: 1 C. coli isolates) was found in 12 class I integrase-positive isolates.

Conclusions

Our results suggested an important information in the latency of Campylobacter species with resistance genes, and irrational antimicrobial use should be concerned.

Electronic supplementary material

The online version of this article (doi:10.1186/s13099-017-0199-4) contains supplementary material, which is available to authorized users.

Plant-derived antimicrobials to fight against multi-drug-resistant human pathogens

Antibiotic resistance is becoming a pivotal concern for public health that has accelerated the search for new antimicrobial molecules from nature. Numbers of human pathogens have inevitably evolved to become resistant to various currently available drugs causing considerable mortality and morbidity worldwide. It is apparent that novel antibiotics are urgently warranted to combat these life-threatening pathogens. In recent years, there have been an increasing number of studies to discover new bioactive compounds from plant origin with the hope to control antibiotic-resistant bacteria. This review attempts to focus and record the plant-derived compounds and plant extracts against multi-drug-resistant (MDR) pathogens including methicillin-resistant Staphylococcus aureus (MRSA), MDR-Mycobacterium tuberculosis and malarial parasites Plasmodium spp. reported between 2005 and 2015. During this period, a total of 110 purified compounds and 60 plant extracts were obtained from 112 different plants. The plants reviewed in this study belong to 70 different families reported from 36 countries around the world. The present review also discusses the drug resistance in bacteria and emphasizes the urge for new drugs.

Development and evaluation of a PCR assay for rapid detection of azithromycin resistant Campylobacter isolated from diarrhoeal patients in Kolkata, India

Background

Campylobacter is a well-known bacterial pathogen for triggering acute gastroenteritis in humans both in developed and developing countries. This organism is highly resistant to fluoroquinolones. Macrolides are very much useful for the treatment of campylobacteriosis when clinical therapy is necessary. However, increasing resistance to azithromycin, a potent macrolide has been reported in Campylobacter in recent years. Macrolide resistance in Campylobacter is found mainly due to point mutation in V region of 23S rRNA.

Results

We have developed a PCR based assay, which can detect the azithromycin resistant and sensitive Campylobacter strains utilizing mutation responsible for the phenotype. This PCR was validated using 359 Campylobacter strains isolated from diarrhoeal patients at Kolkata, India. Antimicrobial resistance through disk diffusion method was also performed on these strains as a gold standard. Studies through sequencing analysis further confirmed the PCR result.

Conclusion

This study describes a simple and rapid method for detection of mutation conferring macrolide resistance with additional feature of identification of sensitive strains.

Antibiotic susceptibility profiles among Campylobacter isolates obtained from international travelers between 2007 and 2014

Campylobacter infection is a common cause of diarrhea among international travelers. We studied antibiotic resistance patterns among Campylobacter isolates obtained from international travelers according to travel destination. Three collections of isolates obtained from international travelers between 2007 and 2014 (Institute of Tropical Medicine, the “Laboratoire Hospitalier Universitaire de Bruxelles “and the Belgian National Reference Centre for Campylobacter) were used. Isolates were tested for minimal inhibitory concentration (MIC) values (E-test macromethod) for fluoroquinolones, macrolides, tetracyclines, amoxicillin–clavulanic acid, and meropenem. Single isolates from 261 travelers were available; median (IQR) age was 25.4 (4–42) years, 85.8% were symptomatic (information for 224 patients available). Overall resistance to ciprofloxacin was 60.9%, ranging from 50.8% in Africa to 75.0% in Asia. Resistance to erythromycin was 4.6%, with the highest rate observed for Southern Asia (15.2%, seven isolates, six of them recovered from patients returning from India). A total of 126 isolates (48.3%) were resistant to tetracycline. No resistance to amoxicillin–clavulanic acid or meropenem was detected. Ciprofloxacin resistance tended to increase over time (53.9% in 2007 versus 72.2% in 2014), erythromycin resistance remained stable (median annual resistance 4.2%). Most (86.2%) ciprofloxacin-resistant isolates had MIC values ≥32 mg/l, and all erythromycin-resistant isolates had MIC values ≥256 mg/l. Co-resistance to ciprofloxacin and erythromycin was observed in 11 (4.2%) isolates, seven of which came from Southern Asia. Among all regions of travel, more than half of Campylobacter isolates were resistant to ciprofloxacin. Overall resistance to erythromycin was below 5% but reached 15.2% in Southern Asia.

Prevalence and Characterization of Campylobacter jejuni Isolated from Retail Chicken in Tianjin, China

Campylobacter jejuni is an important foodborne pathogen worldwide; however, there is a lack of information on the prevalence and antibiotic-resistant profile of C. jejuni in the People's Republic of China. We determined the prevalence and characteristics of C. jejuni on the retail level in Tianjin, one of the five national central cities in China. A total of 227 samples of chicken wings, legs, and breasts were collected from supermarkets and wet markets; 42 of these samples were confirmed to be positive for Campylobacter contamination. The contamination rates of C. jejuni and other Campylobacter species were 13.7% (31 of 227 samples) and 5.7% (13 of 227 samples), respectively. A group of 31 C. jejuni isolates was subjected to antimicrobial susceptibility testing. All (100%) the selected isolates were resistant to ciprofloxacin and nalidixic acid; 77.4% were resistant to tetracycline, 67.7% to doxycycline, 35.5% to gentamicin, 25.8% to clindamycin and florfenicol, 19.4% to chloramphenicol, and 12.9% to erythromycin and azithromycin. A remarkably high proportion (41.9%) of multidrug-resistant isolates was identified. Multilocus sequence typing was conducted to study the population structure of the C. jejuni strains and their relationship to human isolates. The correlation between antimicrobial resistance traits and certain sequence types (STs) or clonal complexes was determined as well. A great genetic diversity of poultry isolates was identified, with 11 STs belonging to 6 clonal complexes and 11 singleton STs. The novel STs accounted for 40.9% (n = 9) of the 22 STs. ST-21, ST-353, ST-354, ST-443, ST-607, and ST-828 complexes had been previously identified from human isolates. This study revealed an extensive level of antimicrobial resistance and genetic diversity in C. jejuni isolated from chicken products in Tianjin, highlighting the necessity of performing enforced interventions to reduce Campylobacter prevalence in China.

Detection and prevalence of antimicrobial resistance genes in <i>Campylobacter</i> spp. isolated from chickens and humans

Campylobacter spp. are common pathogenic bacteria in both veterinary and human medicine. Infections caused by Campylobacter spp. are usually treated using antibiotics. However, the injudicious use of antibiotics has been proven to spearhead the emergence of antibiotic resistance. The purpose of this study was to detect the prevalence of antibiotic resistance genes in Campylobacter spp. isolated from chickens and human clinical cases in South Africa. One hundred and sixty one isolates of Campylobacter jejuni and Campylobacter coli were collected from chickens and human clinical cases and then screened for the presence of antimicrobial resistance genes. We observed a wide distribution of the tetO gene, which confers resistance to tetracycline. The gyrA genes that are responsible quinolone resistance were also detected. Finally, our study also detected the presence of the bla_OXA-61, which is associated with ampicillin resistance. There was a higher (p < 0.05) prevalence of the studied antimicrobial resistance genes in chicken faeces compared with human clinical isolates. The tetO gene was the most prevalent gene detected, which was isolated at 64% and 68% from human and chicken isolates, respectively. The presence of gyrA genes was significantly (p < 0.05) associated with quinolone resistance. In conclusion, this study demonstrated the presence of gyrA (235 bp), gyrA (270 bp), bla_OXA-61 and tetO antimicrobial resistance genes in C. jejuni and C. coli isolated from chickens and human clinical cases. This indicates that Campylobacter spp. have the potential of resistance to a number of antibiotic classes.

Susceptibility to 18 drugs and multidrug resistance of Arcobacter isolates from different sources within the Czech Republic

OBJECTIVES

Arcobacter spp. are considered to be potential foodborne pathogens, and consumption of contaminated food containing these bacteria could endanger human and animal health. Arcobacter butzleri and Arcobacter cryaerophilus are the species most frequently isolated from food of animal origin and from other samples. The aim of this study was to evaluate the susceptibility of arcobacters isolated in the Czech Republic. No information about antibiotic susceptibility and multidrug resistance of arcobacters isolated in the Czech Republic is available in the literature before now.

METHODS

The antimicrobial resistance of A. butzleri (n=80) and A. cryaerophilus (n=20) isolated from meat of animal origin, water sources and clinical samples was examined by the disk diffusion method.

RESULTS

Arcobacters were resistant to one or more antimicrobial agents in 99% (99/100) of tested isolates. Most of the Arcobacter isolates were resistant to β-lactam antibiotics, i.e. ampicillin (81.0%), amoxicillin/clavulanic acid (28.0%), cefalotin (73.0%) and aztreonam (93.0%). Arcobacters were also frequently resistant to lincosamides, i.e. clindamycin (98.0%). Of the aminoglycosides, amikacin, gentamicin and tobramycin were evaluated to be the most effective antibiotics among those tested against arcobacters.

CONCLUSIONS

These results demonstrate substantial resistance in Arcobacter isolates to 18 antimicrobial agents commonly used in medical and veterinary medicine. Multidrug resistance was found in 93.8% (75/80) of A. butzleri isolates and 70.0% (14/20) of A. cryaerophilus isolates.

Prevalence and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from children and environmental sources in urban and suburban areas

BACKGROUND

Campylobacteriosis is a dominant bacterial cause of foodborne infection and is considered the main public health problem in Europe and many other countries worldwide. In the study lasting from 2011 to 2013 we compared the prevalence and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from children, domestic animals, poultry meat and surface water in Northern Poland.

RESULTS

During a 3-years study 1973 samples were analysed. The results proved the presence of Campylobacter spp. in 306 (15.5%) samples. The percentage of Campylobacter-positive samples differed among the sample types, from 0% (freshwater beaches) to 38.6% (poultry meat in 2011). Prevalence of Campylobacter spp. in children isolates was 9.6%. It decreased from 13.2% in 2011 to 8.0% in 2013. It should be highlighted with a particular concern that Campylobacter jejuni was detected in 20.0% of fountains. All children and poultry meat isolates were susceptible to azithromycin. Two C. coli (3.7%) and four C. jejuni (3.3%) isolated from poultry meat were resistant to erythromycin. The highest percentage of C. jejuni isolates with resistance to ciprofloxacin were found in samples from 80% dogs and 85% ponds. Among isolates resistant to two antimicrobials 74.7% C. jejuni and 59.2% C. coli isolates were resistant to ciprofloxacin as well as to tetracycline. Only one cat C. coli isolate was resistant to both azithromycin and erythromycin. One C. jejuni isolate from a fountain was resistant to four antimicrobial agents (erythromycin, azithromycin, tetracycline and ciprofloxacin).

CONCLUSIONS

The study proved that surface water, poultry meat and pets constituted potential sources of Campylobacter to children. Fountains can be a direct source of children campylobacteriosis but can also pollute other environments with multidrug-resistant Campylobacter. The high resistance to some antimicrobials among the isolates may lead to increasing numbers of difficult-to-treat campylobacteriosis cases among children.

Current and Potential Treatments for Reducing Campylobacter Colonization in Animal Hosts and Disease in Humans

Campylobacter jejuni is the leading cause of bacteria-derived gastroenteritis worldwide. In the developed world, Campylobacter is usually acquired by consuming under-cooked poultry, while in the developing world it is often obtained through drinking contaminated water. Once consumed, the bacteria adhere to the intestinal epithelium or mucus layer, causing toxin-mediated inhibition of fluid reabsorption from the intestine and invasion-induced inflammation and diarrhea. Traditionally, severe or prolonged cases of campylobacteriosis have been treated with antibiotics; however, overuse of these antibiotics has led to the emergence of antibiotic-resistant strains. As the incidence of antibiotic resistance, emergence of post-infectious diseases, and economic burden associated with Campylobacter increases, it is becoming urgent that novel treatments are developed to reduce Campylobacter numbers in commercial poultry and campylobacteriosis in humans. The purpose of this review is to provide the current status of present and proposed treatments to combat Campylobacter infection in humans and colonization in animal reservoirs. These treatments include anti-Campylobacter compounds, probiotics, bacteriophage, vaccines, and anti-Campylobacter bacteriocins, all of which may be successful at reducing the incidence of campylobacteriosis in humans and/or colonization loads in poultry. In addition to reviewing treatments, we will also address several proposed targets that may be used in future development of novel anti-Campylobacter treatments.

The European Union summary report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2015

The data on antimicrobial resistance in zoonotic and indicator bacteria in 2015, submitted by 28 EU Member States (MSs), were jointly analysed by EFSA and ECDC. Resistance in zoonotic Salmonella and Campylobacter from humans, animals and food, and resistance in indicator Escherichia coli as well as meticillin‐resistant Staphylococcus aureus in animals and food were addressed. ‘Microbiological’ resistance was assessed using epidemiological cut‐off (ECOFF) values; for some countries, qualitative data on human isolates were interpreted in a way which corresponds closely to the ECOFF‐defined ‘microbiological’ resistance. In Salmonella from humans, high proportions of isolates were resistant to ampicillin, sulfonamides and tetracyclines, whereas resistance to third‐generation cephalosporins was low. In Salmonella and Escherichia coli isolates from fattening pigs and calves under one year of age, resistance to ampicillin, tetracyclines and sulfonamides was frequently detected, whereas resistance to third‐generation cephalosporins was uncommon. For the first time, presumptive extended‐spectrum beta‐lactamase (ESBL)‐/AmpC‐/carbapenemase‐production in Salmonella and Escherichia coli was monitored in humans (Salmonella), meat (pork and beef), fattening pigs and calves. Varying occurrence/prevalence rates of ESBL‐/AmpC‐producers were observed between countries, and carbapenemase‐producing Escherichia coli were detected in single samples of pig meat and from fattening pigs from two MSs. Resistance to colistin was observed at low levels in Salmonella and Escherichia coli from fattening pigs and calves under one year of age and meat thereof. In Campylobacter from humans, high to extremely high proportions of isolates were resistant to ciprofloxacin and tetracyclines, particularly in C. coli. In a few countries, a third to half of C. coli in humans were resistant also to erythromycin, leaving few options for treatment of severe Campylobacter infections. High resistance to ciprofloxacin and tetracyclines was observed in C. coli isolates from fattening pigs, whereas much lower levels were recorded for erythromycin. Co‐resistance to critically important antimicrobials in both human and animal isolates was generally uncommon.