Resistant Campylobacter Research Articles

Engineering the Campylobacter jejuni N-glycan to create an effective chicken vaccine.

Campylobacter jejuni is a predominant cause of human gastroenteritis worldwide. Source-attribution studies indicate that chickens are the main reservoir for infection, thus elimination of C. jejuni from poultry would significantly reduce the burden of human disease. We constructed glycoconjugate vaccines combining the conserved C. jejuni N-glycan with a protein carrier, GlycoTag, or fused to the Escherichia coli lipopolysaccharide-core. Vaccination of chickens with the protein-based or E. coli-displayed glycoconjugate showed up to 10-log reduction in C. jejuni colonization and induced N-glycan-specific IgY responses. Moreover, the live E. coli vaccine was cleared prior to C. jejuni challenge and no selection for resistant campylobacter variants was observed. Analyses of the chicken gut communities revealed that the live vaccine did not alter the composition or complexity of the microbiome, thus representing an effective and low-cost strategy to reduce C. jejuni in chickens and its subsequent entry into the food chain.

Prevalence and antimicrobial resistance of Campylobacter species isolated from the avian eggs

Campylobacter is one of the most important food borne pathogens that cause bacterial gastroenteritis worldwide. The most commonly isolated species in humans are Campylobacter jejuni (C. jejuni) and Campylobacter coli. The emergence of antimicrobial resistance in Campylobacter spp. has been a growing public health concern globally. Information about antimicrobial resistance of Campylobacter at different levels of production is important for the development of control strategies for this pathogen. This study was conducted to determine the prevalence and antimicrobial resistance of Campylobacter spp. isolated from different eggs from different avian species in Iran. A total of 440 egg samples were collected from different avian and analyzed for the presence of Campylobacter spp. in eggshell and eggs content under sterile conditions using Campylobacter selective agar base and the species were identified by biochemical tests. The suspected colonies were subjected to PCR assay for final confirmation as Campylobacter spp., and identification of C. jejuni or Campylobacter coli. Antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method using Mueller Hinton agar. Campylobacters were detected in a total of 7 out of 100 (7%) eggshell of chicken samples and in 3 out of 60 (5%) eggshell of duck samples. In addition, Campylobacter spp. were also detected in 3.3%, 2.5%, 4.2%, 5% and 3.8 of the eggshell of goose, ostrich, partridge, quail and turkey samples, respectively. The overall prevalence rate of Campylobacter species from different avian eggs was found to be 7.7% (34/440). Among different avian egg samples, Campylobacter jejuni was more frequently isolated 28 (n = 28, 6.3%) than C. coli 6 (n = 6, 1.3%). In addition, the prevalence of C. jejuni was highest in summer and lowest in autumn. In this study Campylobacter spp. showed significant difference in resistance pattern with tetracycline and ciprofloxacin but gentamicin resistance was not found in both C. coli and C. jejuni isolates. Therefore, gentamicin is safe and effective drugs for the treatment of human campylobacteriosis if avian egg is considered as the source of infection.

Genotyping and antibiotic resistance of thermophilic Campylobacter isolated from chicken and pig meat in Vietnam.

BackgroundCampylobacter species are recognized as the most common cause of foodborne bacterial gastroenteritis in humans. In this study nine Campylobacter strains isolated from chicken meat and pork in Hanoi, Vietnam, were characterized using molecular methods and tested for antibiotic resistance. ResultsThe nine isolates (eight C. jejuni and one C. coli) were identified by multiplex PCR, and tested for the presence or absence of 29 gene loci associated with virulence, lipooligosaccharide (LOS) biosynthesis and further functions. flaA typing, multilocus sequence typing and microarray assay investigation showed a high degree of genetic diversity among these isolates. In all isolates motility genes (flaA, flaB, flhA, fliM), colonization associated genes (cadF, docB), toxin production genes (cdtA, cdtB, secD, secF), and the LOS biosynthesis gene pglB were detected. Eight gene loci (fliY, virB11, Cje1278, Cj1434c, Cj1138, Cj1438c, Cj1440c, Cj1136) could not be detected by PCR. A differing presence of the gene loci ciaB (22.2 %), Cje1280 (77.8 %), docC (66.7 %), and cgtB (55.6 %) was found. iamA, cdtC, and the type 6 secretion system were present in all C. jejuni isolates but not in C. coli. flaA typing resulted in five different genotypes within C. jejuni, MLST classified the isolates into seven sequence types (ST-5155, ST-6736, ST-2837, ST-4395, ST-5799, ST-4099 and ST-860). The microarray assay analysis showed a high genetic diversity within Vietnamese Campylobacter isolates which resulted in eight different types for C. jejuni. Antibiotic susceptibility profiles showed that all isolates were sensitive to gentamicin and most isolates (88.8 %) were sensitive to chloramphenicol, erythromycin and streptomycin. Resistance rates to nalidixic acid, tetracycline and ciprofloxacin were 88.9, 77.8 and 66.7 %, respectively.ConclusionsTo the best of our knowledge, this study is the first report that shows high genetic diversity and remarkable antibiotic resistance of Campylobacter strains isolated from meat in Vietnam which can be considered of high public health significance. These preliminary data show that large scale screenings are justified to assess the relevance of Campylobacter infections on human health in Vietnam.

Molecular subtyping and erythromycin resistance of Campylobacter in China.

To investigate the erythromycin resistance patterns and mechanism for Campylobacter isolates in China. The minimum inhibitory concentrations of erythromycin on 858 Chinese Campylobacter isolates were analysed. PCR and DNA sequencing were used to identify mutations in the 23S rRNA and the presence of the ermB gene in the 158 erythromycin resistance isolates (18·4%). About 83% (131/158) had A2075G mutation in their 23S rRNA; no A2074C/G mutants were found. The ermB gene was identified in 30 Campylobacter coli isolates (19%). Four types of multidrug-resistant gene islands (MDRGIs) were found. Fifty-three types were identified by multilocus sequence typing among the resistant isolates. All isolates of STs 6322 and 1145 had the ermB gene. The erythromycin resistance rate of Camp.coli (58·56%) was much higher than Campylobacter jejuni (0·67%). The insertion sites between cadF and CCO1582 and between nfsB and cinA on the chromosome might be hot spots for MDRGI transformation. Point mutation in domain V of the 23S rRNA and the ermB gene accounted for 100% of the erythromycin resistance of Campylobacter in China.

Molecular Characterization, Antimicrobial Resistance and Caco-2 Cell Invasion Potential of Campylobacter jejuni/coli from Young Children with Diarrhea.

Campylobacter is a major cause of bacterial gastroenteritis worldwide. Young children represent a particular age group affected by Campylobacter infection because of their limited diets and weak immune systems. In this study, a total of 110 Campylobacter (80 Campylobacter jejuni and 30 Campylobacter coli) isolated from children younger than 5 years of age with diarrhea in Shanghai, China in 2011 were examined for their genetic relationship and antimicrobial susceptibility. The presence of virulence genes and its association with invasion potential in Caco-2 cell were also determined. Multilocus sequence typing revealed 62 sequence types (STs) under 14 clonal complexes from C. jejuni and 15 STs under 2 clonal complexes from C. coli. High resistance rates among the 110 isolates were observed to nalidixic acid (88.2%), ciprofloxacin (87.3%) and tetracycline (87.3%), followed by ampicillin (30.9%), gentamicin (28.2%), clindamycin (21.8%), erythromycin (21.8%) and chloramphenicol (8.2%). Compared with that of C. jejuni (32.5%), a larger proportion of C. coli (83.3%) were resistant to multiple antimicrobials, including 16 isolates of ST-828 complex resistant to 6 antimicrobials: ciprofloxacin, clindamycin, erythromycin, gentamicin, nalidixic acid and tetracycline. Furthermore, 57 Campylobacter isolates were selected based on their distinct STs and the presence of virulence genes to determine their abilities to adhere to and invade Caco-2 cells. The level of invasion varied widely among isolates and had relatively weak correlation with the genotype data. Our findings provided baseline data on Campylobacter among young children. Active surveillance of Campylobacter is needed to better understand the epidemiology and antimicrobial resistance trends of this significant pathogen to help control and protect young children from such infections.

Incidence and Antimicrobial Resistance of Campylobacter and Salmonella from Houseflies (Musca Domestica) in Kitchens, Farms, Hospitals and Slaughter Houses

Carriage status of Campylobacter and Salmonella was investigated in houseflies in Shahrekord and Isfahan provinces of Iran. This was a longitudinal study conducted from June 2013 to May 2014. Flies were collected from household kitchens, animal farms, slaughter houses and hospitals and put in sample bottles filled with peptone water. Bacteria were isolated and DNA was extracted from bacterial isolates using a commercial kit. Confirmation of the organisms was carried out by polymerase chain reaction using primer sets for detection of these pathogens. Out of 600 houseflies 19.5 % (117/600) were positive for Campylobacter and 15.8 % (95/600) were positive for Salmonella organisms. The recovery frequencies of the two organisms in different locations were similar. Higher proportions of infected flies were obtained during summer whereas low proportions were obtained during winter of all the organisms (P < 0.05). The organisms had low to moderate resistance to different antimicrobial agents. It is concluded that houseflies do harbor antimicrobial resistant diarrheagenic pathogens including Campylobacter and Salmonella, more so during summer. The data support the importance of taking into account the houseflies in future plans aimed at stemming infections caused by these organisms.

Baseline study for prevalence of resistant and susceptible campylobacter in retail ground beef

Baseline study for prevalence of resistant and susceptible campylobacter in retail ground beef

Campylobacter jejuni and Campylobactercoli in Children With Acute Diarrhea in Health Centers of Hamadan, Iran

Background: Enteritis caused by Campylobacter is considered as the most common acute bacterial diarrhea around the world. In most cases, infection occurs as a result of consuming contaminated water or food, especially raw meat of fowls. Objectives: The purpose of the present study was to determine the prevalence and antibiotic resistance of campylobacter species among pediatrics of Hamadan city, Iran. Patients and Methods: A total of 120 stool samples from children less than 10 years old were examined from January 2013 to December 2014 in Hamadan, Iran. The samples were incubated in Campy-Thio enrichment medium for 1 - 2 hours and then cultured on a specific medium; after that, the suspected colonies were analyzed for Campylobacter spp. identification by conventional tests. The identified species by biochemical methods were confirmed by polymerase chain reaction (PCR). Antimicrobial susceptibility testing was performed by disk agar diffusion (DAD) method. Results: Twelve (10%) Campylobacter spp. from 120 stool samples were isolated including C. coli and C. jejuni. In the antibiotic susceptibility test, the most frequent resistance was observed to ciprofloxacin 8 (88.8%), followed by 7 (77.7%) resistant strains to tetracycline, 7 (77.7%) to erythromycin, 6 (66.6%) to clindamycin, 5 (55.5%) to meropenem, 4 (44.4%) to gentamicin, 3 (33.3%) to nalidixicacid and only 1 (11.1%) to chloramphenicol. Conclusions: Campylobacter is responsible for some important clinical problems such as enteritis and is also associated with meningitis and hemolytic-uremic syndrome. It is imperative to monitor the prevalence and antibiotic resistance of Campylobacter spp. as well as other the zoonotic bacteria.

Species shift and multidrug resistance of Campylobacter from chicken and swine, China, 2008-14.

The objective of this study was to investigate the prevalence and antimicrobial resistance of Campylobacter isolated from broiler chickens and swine during 2008-14. Campylobacter isolates were collected from samples of intestinal content and excreta from broiler chickens and swine from slaughter houses as well as conventional farms in five Chinese provinces during 2008-14. The agar dilution method was used to determine the susceptibility of Campylobacter isolates to seven antimicrobial agents. The χ(2) test and Fisher's exact test were used to perform the statistical analysis. In total, 989 Campylobacter jejuni and 1991 Campylobacter coli were isolated from 10 535 samples. MIC results revealed a high prevalence of multidrug resistance among these Campylobacter isolates. In addition, we observed an apparent shift of the dominant species from C. jejuni to C. coli in chickens and this species shift coincided with an increased prevalence of macrolide-resistant C. coli. It is worth noting that almost 100% of the C. jejuni and C. coli isolates were resistant to fluoroquinolones. The high prevalence of fluoroquinolone and macrolide resistance in Campylobacter suggests that these two clinically important antibiotic classes may no longer be suitable for the treatment of human campylobacteriosis in China. Thus, enhanced surveillance and control efforts are needed to reduce antimicrobial resistance in this group of major foodborne pathogens.

Antimicrobial Resistance and Genotypic Diversity of Campylobacter Isolated from Pigs, Dairy, and Beef Cattle in Tanzania.

Foodborne Campylobacter infections pose a serious threat to public health worldwide. However, the occurrence and characteristics of Campylobacter in food animals and products remain largely unknown in Tanzania. The objective of this study was to determine the prevalence, antibiotic resistance, and genetic profiles (sequence types, STs) of Campylobacter isolated from feces of pigs and dairy and beef cattle in Tanzania. Overall, 259 (~30%) of 864 samples were positive for Campylobacter spp, which were detected in 32.5, 35.4, and 19.6% of the pig, dairy, and beef cattle samples, respectively. Multiplex PCR analysis identified 64.5 and 29.3% of the Campylobacter isolates as C. coli and C. jejuni, respectively. The majority (91.9%) of the isolates from pig samples were identified as C. coli, while C. jejuni accounted for 65.5% of the isolates from cattle. Antimicrobial susceptibility testing using the disk diffusion assay and the broth microdilution method revealed resistance to: ampicillin (Amp) (70.3% and 75.7%, respectively), gentamicin (Gen) (1.8% and 12.6%), streptomycin (Str) (65.8 and 74.8%), erythromycin (Ery) (41.4 and 48.7%), tetracycline (Tet) (18.9 and 23.4%), and ciprofloxacin (Cip) (14.4 and 7.2%). Resistance to nalidixic acid (Nal) (39.6%), azithromycin (Azm) (13.5%), and chloramphenicol (Chl) (4.5%) was determined using the disk diffusion assay only, while resistance to tylosin (Tyl) (38.7%) was quantified using the broth microdilution method. Multilocus sequence typing of 111 Campylobacter isolates resulted in the identification of 48 STs (26 C. jejuni and 22 C. coli) of which seven were novel (six C. jejuni and one C. coli). Taken together, this study revealed the high prevalence, genetic diversity and antimicrobial resistance of Campylobacter in important food animals in Tanzania, which highlights the urgent need for the surveillance and control of Campylobacter in this country.

Detection of fluoroquinolone resistance by mutation in gyrA gene of Campylobacter spp. isolates from broiler and laying (Gallus gallus domesticus) hens,from Rio de Janeiro State, Brazil

Poultry are considered to be the main reservoir of Campylobacter spp. bacteria, an important pathogen for humans. Many studies have reported a rapid selection of fluoroquinolone-resistant strains following the widespread use of these antimicrobials in poultry production and human medicine. The main mechanism of fluoroquinolone resistance in Campylobacter is a mutation in the Quinolone Resistance Determinant Region (QRDR) in the gyrA gene, which codes for the subunit of the enzyme DNA gyrase, the target for fluoroquinolone. The aim of this study was to investigate the mutation in QRDR in the gyrA gene of Campylobacter strains previously isolated from broiler carcasses and feces of laying hens. Thirty-eight strains of C. jejuni and 19 C. coli strains (n=57), previously characterized as resistant to ciprofloxacin and enrofloxacin by the disk diffusion method and minimum inhibitory concentration (MIC), were selected. For detection of the mutation, a fragment of 454pb QRDR in the gyrA gene was used for direct sequencing. All strains presented the QRDR mutation in the gyrA gene at codon 86 (Thr-86-Ile), which confers resistance to fluoroquinolones. Other known silent mutations were observed. This genotypic characterization of fluoroquinolone resistance in Campylobacter strains has confirmed the prior phenotypic detection of the resistance. The Thr-86-Ile mutation was observed in all samples confirming that this is the predominant mutation in enrofloxacin and ciprofloxacin resistant strains of C. jejuni and C. coli.

Antimicrobial susceptibilities of Campylobacter jejuni and Campylobacter coli recovered from organic turkey farms in Germany

The popularity of food produced from animals kept under an organic regimen has increased in recent years. In Germany, turkey meat consumption has increased. Despite several studies assessing the susceptibility of campylobacters to various antibiotics in poultry, no sufficient data exists regarding the antimicrobial resistance of campylobacters in organic-reared turkeys. This study provides information about antibiotic resistance in Campylobacter isolated from turkeys reared on organic farms in Germany. Ninety-six Campylobacter strains (41 C. jejuni and 55 C. coli) were isolated from different free-range turkey flocks. In vitro antimicrobial sensitivity testing was done using a broth microdilution test, and the presence of resistance genes to antibiotics (ciprofloxacin, tetracycline) was investigated. All Campylobacter isolates from organic turkeys (n = 96) were phenotypically sensitive to gentamicin, erythromycin, streptomycin, and chloramphenicol. In this study, the antibiotic susceptibilities of C. jejuni to ciprofloxacin, tetracycline, and naladixic acid were 56.0%, 51.3%, and 56.0%, respectively. In contrast, 44.0%, 73.0%, and 74.6% of C. coli isolates were resistant to tetracycline, ciprofloxacin, and nalidixic acid, respectively. Replacement of the Thr-86→Ile in the gyr A gene, and the presence of the tet(O) gene were the mainly identified resistance mechanisms against fluoroquinolones and tetracycline, respectively. These results also reinforce the need to develop strategies and implement specific control procedures to reduce the development of antimicrobial resistance.

Prevalence and antimicrobial resistance of Campylobacter spp. isolated from retail chicken and duck meat in South Korea

This study was conducted to determine the prevalence and antimicrobial resistance of Campylobacter isolates from chicken and duck meat in South Korea. A total of 149 Campylobacter spp. was isolated and 124 (66.7%) isolates were identified as Campylobacter jejuni, 24 (12.9%) isolates as Campylobacter coli, and one was unidentified. There were 102 isolates from retail duck meat with the isolation rate of 96.2%, which was significant higher (p < 0.05) than 47 isolates from 80 of chicken meat with the isolation rate of 58.8%. Campylobacter isolation rates ranged from 83.3% to 100.0% among traditional markets, wholesale markets and supermarkets; whereas the isolation rate from online store (50.0%) was significantly lower (p < 0.01) than the traditional markets, wholesale markets and supermarkets. Resistance to nalidixic acid, tetracycline and ciprofloxacin was most common both for chicken and duck Campylobacter isolates. All 24 C. coli isolates were resistant to tetracycline. Campylobacter isolates from duck had higher antibiotics resistant rates to ampicillin, ciprofloxacin, gentamicin, nalidixic acid and tetracycline, than chickens. The majority of the Campylobacter isolates were classified as multi-drug resistant, 57.1% of the C. jejuni isolates and 70.9% C. coli isolates were resistant to at least four antibiotics tested in this study. One C. jejuni isolate showed resistance to all eight antibiotics tested in this study. Our results show that retail chicken and duck meat has a high prevalence of Campylobacter, and the high prevalence of resistant and multi-drug resistant Campylobacter in retail chicken and duck meat is a potential campylobacteriosis risk for humans living in South Korea.

Prevalence and fluoroquinolones resistance of Campylobacter and Salmonella isolates from poultry carcasses in Rio de Janeiro, Brazil

To investigate the prevalence of Campylobacter and Salmonella in poultry carcasses in state of Rio de Janeiro, Brazil, 60 samples from 6 slaughterhouses were collected over a period of 6 months. A total of 82 Campylobacter isolates were obtained from twenty seven (45%) positive chicken carcasses, including 44 isolates (53.66%) of Campylobacter jejuni and 38 (46.34%) of Campylobacter coli. The identification of all strains was confirmed by PCR. Salmonella was isolated from 4 (6.67%) carcasses by conventional method and was detected in 5 (8.33%) of 60 chicken carcasses by PCR. Two Salmonella Albany and two Salmonella Typhimurium were identified. Antimicrobial susceptibility testing was primarily done by the disk diffusion method and later by assessing minimum inhibitory concentrations (MICs) against all the isolates. All the Campylobacter isolates were resistant to ciprofloxacin and enrofloxacin. It was observed high MIC values for enrofloxacin (64 μg/mL) in one C. jejuni and two C. coli strains, and for ciprofloxacin (≥128 μg/mL) in one C. jejuni and three C. coli strains. No Salmonella isolate was resistant to these antibiotics by both methods. These findings reveal a broad extent of fluoroquinolone resistance in Campylobacter isolates from chicken carcasses in Brazil and underline the need for prudent use of these antibiotics in poultry production to minimize the spread of fluoroquinolone resistant Campylobacter.

Synergistic anti-Campylobacter jejuni activity of fluoroquinolone and macrolide antibiotics with phenolic compounds.

The increasing resistance of Campylobacter to clinically important antibiotics, such as fluoroquinolones and macrolides, is a serious public health problem. The objective of this study is to investigate synergistic anti-Campylobacter jejuni activity of fluoroquinolones and macrolides in combination with phenolic compounds. Synergistic antimicrobial activity was measured by performing a checkerboard assay with ciprofloxacin and erythromycin in the presence of 21 phenolic compounds. Membrane permeability changes in C. jejuni by phenolic compounds were determined by measuring the level of intracellular uptake of 1-N-phenylnaphthylamine (NPN). Antibiotic accumulation assays were performed to evaluate the level of ciprofloxacin accumulation in C. jejuni. Six phenolic compounds, including p-coumaric acid, sinapic acid, caffeic acid, vanillic acid, gallic acid, and taxifolin, significantly increased the susceptibility to ciprofloxacin and erythromycin in several human and poultry isolates. The synergistic antimicrobial effect was also observed in ciprofloxacin- and erythromycin-resistant C. jejuni strains. The phenolic compounds also substantially increased membrane permeability and antibiotic accumulation in C. jejuni. Interestingly, some phenolic compounds, such as gallic acid and taxifolin, significantly reduced the expression of the CmeABC multidrug efflux pump. Phenolic compounds increased the NPN accumulation in the cmeB mutant, indicating phenolic compounds may affect the membrane permeability. In this study, we successfully demonstrated that combinational treatment of C. jejuni with antibiotics and phenolic compounds synergistically inhibits C. jejuni by impacting both antimicrobial influx and efflux.

English

The emergence of multi-drug resistant microbes necessitates a continuous search for newer, effective antimicrobial agents. The crude methanol leaf extract of Vernonia glaberrima was screened for its antimicrobial activity against pathogenic microorganisms including Methicillin resistant Staphylococcus aureus, Vancomycin resistant enterococci, Listeria monocytogenes, Staphylococcusau reus, Helicobacter pylori, Campylobacter fetus, Proteus vulgaris, Pseudomonas fluorescens, Candida tropicalis and Candida stellatoidea using agar diffusion and broth dilution methods. The result of the susceptibility test showed the extract (400&mu;g) inhibited the growth of Methicillin-resistance S. aureus, Vancomycin resistant enterococci, S. aureus, H. pylori, P. fluorescens and C. stellatoidea with mean zone of inhibition range of 18 to 29 mm; the most susceptible organism was S. aureus (29 mm) and the least was the fungus, C. stellatoidea &nbsp;(18 mm). No activity was observed against L. monocytogenes, C. fetus, P. vulgaris and C. tropicalis. Sparfloxacin (5&micro;g/ml) the standard antibacterial drug, had inhibitory activity against all the test organisms except H. pylori, P. flourescens, C. tropicalis and C. stellatoidea while the standard anti-fungal drug, Fluconazole (5&micro;g/ml), showed activity only on the two fungi species, C. tropicalis and C. stellatoidea. The Minimum inhibitory concentration (MIC) and the minimum bactericidal/fungicidal concentration (MBC/MFC) ranges for the extract were 5 to 20 mg/ml and 10 to 40 mg/ml, respectively. The results of this study suggest that the methanol leaf extract of V. glaberrima contains bioactive principles that have good antibacterial and antifungal activity, validating the antimicrobial use of the plant in traditional medicine. &nbsp; Key words: Vernonia glaberrima, extract, antimicrobial, MIC, MBC, evaluation.

Antibiotic resistance and polymorphism in the quinolone resistance-determining region of Campylobacter spp. isolated from 1-day-old ducklings

Thirty-three isolates of Campylobacter coli and three isolates of Campylobacter jejuni were recovered from 150 1-day-old ducklings. All isolates were sensitive to chloramphenicol and amikacin, but resistant to sulfamethoxazole-trimethoprim (SXT) by the disc diffusion method. Most isolates were susceptible to tetracycline and erythromycin, but resistant to ofloxacin and ciprofloxacin. Of the 33 C. coli isolates, nine were positive for the tetracycline resistance gene tet(O), although only two of these were resistant to tetracycline in the disc diffusion test. None of the isolates possessed mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene infrequently linked to FQ-resistance. The finding indicated that ducklings may be a source of antibiotic resistant Campylobacter spp. with potential poultry and public health hazard.

Regulation of oxidative stress resistance in Campylobacter jejuni, a microaerophilic foodborne pathogen.

Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis. Due to the increasing rates of human campylobacteriosis, C. jejuni is considered as a serious public health concern worldwide. C. jejuni is a microaerophilic, fastidious bacterium. C. jejuni must overcome a wide range of stress conditions during foodborne transmission to humans, such as food preservation and processing conditions, and even in infection of the gastrointestinal tracts of humans. Particularly, this microaerophilic foodborne pathogen must survive in the atmospheric conditions prior to the initiation of infection. C. jejuni possesses unique regulatory mechanisms for oxidative stress resistance. Lacking OxyR and SoxRS that are highly conserved in other Gram-negative foodborne pathogens, C. jejuni modulates the expression of genes involved in oxidative stress resistance mainly via the peroxide resistance regulator and Campylobacter oxidative stress regulator. Based on recent findings of ours and others, in this review, we described how C. jejuni regulates the expression of oxidative stress defense.

Prevalence and Antimicrobial Resistance ofCampylobacterIsolated from Dressed Beef Carcasses and Raw Milk in Tanzania

Campylobacter species are commonly transmitted to humans through consumption of contaminated foods such as milk and meat. The aim of this study was to investigate the prevalence, antimicrobial resistance, and genetic determinants of resistance of Campylobacter isolated from raw milk and beef carcasses in Tanzania. The antimicrobial resistance genes tested included blaOXA-61 (ampicillin), aph-3-1 (aminoglycoside), tet(O) (tetracycline), and cmeB (multi-drug efflux pump). The prevalence of Campylobacter was 9.5% in beef carcasses and 13.4% in raw milk, respectively. Using multiplex-polymerase chain reaction (PCR), we identified 58.1% of the isolates as Campylobacter jejuni, 30.7% as Campylobacter coli, and 9.7% as other Campylobacter spp. One isolate (1.6%) was positive for both C. jejuni and C. coli specific PCR. Antimicrobial susceptibility testing using the disk diffusion assay and the broth microdilution method showed resistance to: ampicillin (63% and 94.1%), ciprofloxacin (9.3% and 11.8%), erythromycin (53.7% and 70.6%), gentamicin (0% and 15.7%), streptomycin (35.2% and 84.3%), and tetracycline (18.5% and 17.7%), respectively. Resistance to azithromycin (42.6%), nalidixic acid (64.8%), and chloramphenicol (13%) was determined using the disk diffusion assay only, while resistance to tylosin (90.2%) was quantified using the broth microdilution method. The blaOXA-61 (52.6% and 28.1%), cmeB (26.3% and 31.3%), tet(O) (26.3% and 31.3%), and aph-3-1 (5.3% and 3.0%) were detected in C. coli and C. jejuni. These findings highlight the extent of antimicrobial resistance in Campylobacter occurring in important foods in Tanzania. The potential risks to consumers emphasize the need for adequate control approaches, including the prudent use of antimicrobials to minimize the spread of antimicrobial-resistant Campylobacter.

Resistance to β-lactam and tetracycline in Campylobacter spp.isolated from broiler slaughterhouses in southern Brazil

Abstract The study was carried out to screen and analyze the genetic characteristics of antimicrobial resistance in Campylobacter spp. from poultry sources. A total of 141 strains of Campylobacter isolated from samples of broilers of slaughterhouses in southern Brazil was identified by phenotypic and genotypic methods. Campylobacter isolates were evaluated for its antimicrobial susceptibility and the presence of resistance genes. The strains were investigated for antimicrobial susceptibility against two agents (ampicillin and tetracycline) by disk diffusion method. PCR assay was used to confirm the specie and the presence of ampicillin (blaOXA-61), tetracycline tet(O), and the energy-dependent multi-drug efflux pump (cmeB) genes. Campylobacter jejuni was the most ubiquitous; its presence was determined in 140 samples out of 141 (99.3%), whereas Campylobacter coli was found only in one of the contaminated samples (0.70%). The results obtained showed 65% and 35.5% of Campylobacter isolates resistant to β-lactams and tetracyclines, respectively. The cmeB gene responsible for multidrug resistance was detected in 26 isolates out 141 strains (18.5%). Moreover, 36 out of 141 Campylobacter strains (25.6%) were found to be resistant to at least two different antimicrobia resistance markers (β-lactams and tetracyclines).