Quinolone-resistant Campylobacter jejuni infections in Minnesota, 1992-1998. Investigation Team

Prevalence and Antimicrobial Resistance of Campylobacter in Conventional and No Antibiotics Ever Broiler Farms

Campylobacter is a leading cause of enteric disease worldwide. No antibiotics ever (NAE) poultry has become increasingly popular, yet little is known about the incidence and antimicrobial resistance (AMR) of Campylobacter in this production system. This study was conducted to determine the prevalence, concentration, and AMR of Campylobacter in conventional (CV) and NAE-raised broilers. Two CV and two NAE commercial broiler flocks were included in this study. Cecum (n = 420) and ileum (n = 420) of chickens were collected at different stages during the broiler grow-out phase and following transportation to the processing plant. Samples of litter (n = 24), feed (n = 24), and water (n = 24) were also collected. Screening for Campylobacter was conducted using real-time PCR assay, and enumeration was performed by direct plating on Campy Cefex agar. Campylobacter isolates were confirmed by real-time PCR, and antimicrobial susceptibility was evaluated following the National Antimicrobial Resistance Monitoring System (NARMS) methods. Whole Genome Sequencing (WGS) was used to identify AMR genes carried by the resistant isolates. Campylobacter prevalence reached 100% within the first 3 weeks of summer production under both NAE and CV rearing. A lower Campylobacter prevalence was detected in conventionally raised broilers during fall (P ≤ 0.05), yet no change in prevalence was observed in NAE birds (P > 0.05). Populations were high in the cecum, carrying an average of 6.6 Log10 CFU/g after transportation, and antimicrobial-resistant Campylobacter was isolated from CV broilers during the fall. Three isolates (1.2%), identified as C. coli, carrying the gyrA and tet(O) genes, exhibited simultaneous resistance to ciprofloxacin, tetracycline, and nalidixic acid. Results from this study can help identify important shifts in gut microbial community dynamics and Campylobacter prevalence associated with antibiotic administration within commercial poultry operations.

Rapid Environmental Impact Assessment of Penicillin G in a Veterinary Product Using an Original Software Method and Monitoring by SPE-Online-UHPLC-MS/MS

Veterinary antibiotics have become a major concern due to potential environmental effects. This study presents an investigation of the exposure and environmental effects of the veterinary medicinal product in powder form, administered in the drinking water of piglets, chickens and turkeys, containing 250 mg/g penicillin G (benzylpenicillin potassium), performed according to the European Medicines Agency (EMEA) guideline and the results obtained by an analytical method based on online solid-phase extraction, ultra-high performance liquid chromatography coupled to a triple quadrupole mass spectrometer (SPE-online-UHPLC-MS/MS). The study presents the determination of the environmental risk and through an original, interactive, fast software method, created on the basis of a proprietary calculation algorithm that goes through all the prescriptions and recommendations of the EMEA guide. The results demonstrated that the concentration value for penicillin G determined in surface water by SPE-online-UHPLC-MS/MS is much lower than that predicted by calculation (predictable concentration in surface water, PECsurface water = 37.66 µg/L and the concentration SPE-online-UHPLC-MS/MS = 0.032 µg/L). Both results lead to a sub-unit risk quotient (R) indicating that the treatment carried out with the considered veterinary product does not present any risk to the environment.

Effects of partial or complete replacement of soybean meal with commercial black soldier fly larvae (Hermetia illucens) meal on growth performance, cecal short chain fatty acids, and excreta metabolome of broiler chickens

Black soldier fly larvae meal (BSFLM) is receiving great attention as a rich source of protein and antimicrobials for poultry. Therefore, we evaluated the effects of partially or completely replacing soybean meal (SBM) with commercial BSFLM on growth performance, tibia traits, cecal short chain fatty acid (SCFA) concentrations, and excreta metabolomes in broiler chickens (Gallus gallus domesticus). A total of 480 day-old male Ross × Ross 708 chicks were assigned to 6 diets (8 replicates/diet): a basal corn-SBM diet with in-feed bacitracin methylene disalicylate (BMD), a corn-SBM diet without BMD (0% BSFLM), and four diets in which the SBM was substituted with 12.5, 25, 50, and 100% BSFLM. Body weight (BW), feed intake (FI) and cumulative feed conversion ratio (cFCR) were monitored on days 14, 28, and 35. Cecal SCFA levels were determined on days 14, 28, and 35. Tibia traits and excreta metabolomes were determined on day (d) 35. On d14, birds fed 12.5 and 25% BSFLM had a similar BW, FI, and cFCR as birds fed BMD (P > 0.05). On d 35, birds fed 12.5% BSFLM had a similar BW, FI and cFCR as birds fed BMD or 0% BSFLM (P > 0.05). For each phase, birds fed 100% BSFLM had a lower BW, FI and higher cFCR than birds fed BMD or 0% BSFLM (P < 0.05). On d 35, BW decreased linearly, quadratically, and cubically with increasing levels of BSFLM (P < 0.01). Overall (d 0-35), BSFLM linearly, quadratically, and cubically decreased FI and quadratically and cubically increased cFCR (P < 0.01). Quadratic responses were observed for tibia fresh weight (P = 0.049) and ash content (P = 0.022). BSFLM did not impact cecal SCFAs levels. The excreta metabolome of birds fed 100% BSFLM clustered independently from all other groups and exhibited greater levels of putatively identified methionine, lysine, valine, glutamine, histidine and lower levels of arginine as compared to all diets. Taken together, substitution of SBM with ≤25% of BSFLM in the starter phase may be used as an alternative to BMD.

Conformational dynamics and putative substrate extrusion pathways of the N-glycosylated outer membrane factor CmeC from Campylobacter jejuni

The outer membrane factor CmeC of the efflux machinery CmeABC plays an important role in conferring antibiotic and bile resistance to Campylobacter jejuni. Curiously, the protein is N-glycosylated, with the glycans playing a key role in the effective function of this system. In this work we have employed atomistic equilibrium molecular dynamics simulations of CmeC in a representative model of the C. jejuni outer membrane to characterise the dynamics of the protein and its associated glycans. We show that the glycans are more conformationally labile than had previously been thought. The extracellular loops of CmeC visit the open and closed states freely suggesting the absence of a gating mechanism on this side, while the narrow periplasmic entrance remains tightly closed, regulated via coordination to solvated cations. We identify several cation binding sites on the interior surface of the protein. Additionally, we used steered molecular dynamics simulations to elucidate translocation pathways for a bile acid and a macrolide antibiotic. These, and additional equilibrium simulations suggest that the anionic bile acid utilises multivalent cations to climb the ladder of acidic residues that line the interior surface of the protein.

Characterisation of burden of illness measures associated with human (Fluoro)quinolone-resistant Campylobacter spp. infections - a scoping review

Campylobacter spp. are one of the most common causes of bacterial gastroenteritis in Canada and worldwide. Fluoroquinolones are often used to treat complicated human campylobacteriosis and strains of Campylobacter spp. resistant to these drugs are emerging along the food chain. A scoping review was conducted to summarise how human (fluoro)quinolone-resistant (FQR; quinolones including fluoroquinolones) Campylobacter spp. infections are characterised in the literature by describing how burden of illness (BOI) associated with FQR is measured and reported, describing the variability in reporting of study characteristics, and providing a narrative review of literature that compare BOI measures of FQR Campylobacter spp. infections to those with susceptible infections. The review identified 26 studies that yielded many case reports, a lack of recent literature and a lack of Canadian data. Studies reported 26 different BOI measures and the most common were hospitalisation, diarrhoea, fever and duration of illness. There were mixed results as BOI measures reported in literature were inconsistently defined and there were limited comparisons between resistant and susceptible infections. This presents a challenge when attempting to assess the magnitude of the BOI due to FQR Campylobacter spp., highlighting the need for more research in this area.

Antimicrobial Resistance and Its Drivers-A Review

Antimicrobial resistance (AMR) is a critical issue in health care in terms of mortality, quality of services, and financial damage. In the battle against AMR, it is crucial to recognize the impacts of all four domains, namely, mankind, livestock, agriculture, and the ecosystem. Many sociocultural and financial practices that are widespread in the world have made resistance management extremely complicated. Several pathways, including hospital effluent, agricultural waste, and wastewater treatment facilities, have been identified as potential routes for the spread of resistant bacteria and their resistance genes in soil and surrounding ecosystems. The overuse of uncontrolled antibiotics and improper treatment and recycled wastewater are among the contributors to AMR. Health-care organizations have begun to address AMR, although they are currently in the early stages. In this review, we provide a brief overview of AMR development processes, the worldwide burden and drivers of AMR, current knowledge gaps, monitoring methodologies, and global mitigation measures in the development and spread of AMR in the environment.

Extended-Spectrum Beta-Lactamases Producing Enterobacteriaceae in the USA Dairy Cattle Farms and Implications for Public Health

Antimicrobial resistance (AMR) is one of the top global health threats of the 21th century. Recent studies are increasingly reporting the rise in extended-spectrum beta-lactamases producing Enterobacteriaceae (ESBLs-Ent) in dairy cattle and humans in the USA. The causes of the increased prevalence of ESBLs-Ent infections in humans and commensal ESBLs-Ent in dairy cattle farms are mostly unknown. However, the extensive use of beta-lactam antibiotics, especially third-generation cephalosporins (3GCs) in dairy farms and human health, can be implicated as a major driver for the rise in ESBLs-Ent. The rise in ESBLs-Ent, particularly ESBLs-Escherichia coli and ESBLs-Klebsiella species in the USA dairy cattle is not only an animal health issue but also a serious public health concern. The ESBLs-E. coli and -Klebsiella spp. can be transmitted to humans through direct contact with carrier animals or indirectly through the food chain or via the environment. The USA Centers for Disease Control and Prevention reports also showed continuous increase in community-associated human infections caused by ESBLs-Ent. Some studies attributed the elevated prevalence of ESBLs-Ent infections in humans to the frequent use of 3GCs in dairy farms. However, the status of ESBLs-Ent in dairy cattle and their contribution to human infections caused by ESBLs-producing enteric bacteria in the USA is the subject of further study. The aims of this review are to give in-depth insights into the status of ESBL-Ent in the USA dairy farms and its implication for public health and to highlight some critical research gaps that need to be addressed.

Comparison of different biomass methodologies to adjust sales data on veterinary antimicrobials in the USA

Objectives

The United States (US) FDA, European Surveillance of Veterinary Antimicrobial Consumption (ESVAC), Public Health Agency of Canada (PHAC) and World Organisation for Animal Health (OIE) established methodologies that characterize antimicrobial sales for use in food animals by adjusting the sales by animal biomass. Our aim was to review and compare these methodologies on US-specific data.

Methods

Annual antimicrobial sales for cattle, swine, chickens and turkeys in the USA between 2016 and 2018 were adjusted by the FDA, ESVAC, PHAC and OIE methodologies. To better understand the advantages and disadvantages of the four methodologies, their biomass denominators were compared regarding the level of detail accounted for in the estimated US livestock biomass, their ability to observe temporal trends in animal biomass within a country and practicality in biomass estimation for comparing antimicrobial sales across countries.

Results

The four methodologies resulted in substantially different estimates of biomass-adjusted antimicrobial sales for use in US food animals. The 2018 estimates were the highest with the ESVAC methodology (314.7 mg of active antimicrobial ingredient/kg of animal biomass), followed by PHAC (191.5 mg/kg), FDA (127.6 mg/kg) and OIE (111.5 mg/kg). The animal weight parameters used in each methodology had the most impact on the biomass-adjusted sales estimates.

Conclusions

In regard to the estimation of the animal biomass, no methodology was found to be perfect; however, the FDA methodology had the best resolution in characterizing the US livestock biomass while the OIE methodology was best for biomass estimation for global monitoring of antimicrobial sales for use in food animals.

Antimicrobial Resistance and Genetic Diversity of Campylobacter spp. Isolated from Broiler Chicken at Three Levels of the Poultry Production Chain in Costa Rica

ABSTRACT

Campylobacter spp. are considered the most common bacterial cause of human gastroenteritis, one of the four main causes of diarrheal disease worldwide, and they are one of the main foodborne pathogens causing hospitalizations and deaths. Here, 148 strains of Campylobacter spp. isolated from poultry at farms, processing plants, and retail stores in Costa Rica were examined for resistance to six antibiotics. An agar dilution test was used to determine the MIC and susceptibility profiles against doxycycline, ciprofloxacin, nalidixic acid, enrofloxacin, chloramphenicol, and erythromycin. In addition, a pulsed-field gel electrophoresis analysis was carried out to determine the genotype relatedness of a representative subset of the isolates. Approximately 136 (92%) of the 148 analyzed isolates showed resistance to the tested drugs. Nalidixic acid, ciprofloxacin, and enrofloxacin were the antibiotics for which resistance occurred most frequently (91.2, 85.8, and 85.8%, respectively), followed by doxycycline (25.0%), chloramphenicol (5.4%), and erythromycin (2.7%). The profile conferring only resistance to quinolones was the most frequently found, and only 2.0% of the isolates showed resistance to quinolones and macrolides simultaneously. Results showed a high frequency of resistant Campylobacter spp. strains and evidenced the distribution, selection, and circulation of resistant strains along the poultry chain from farms to consumers. Cross-contamination and resistance seem to play important roles in the dissemination of these strains at specific points of the poultry chain, even when control measures are being taken. The establishment of effective surveillance and control strategies represents an essential tool for foodborne diseases mitigation. The rational use of antibiotics, especially those still showing efficacy, should be a priority in both human and veterinary medicine to contain the progress of this phenomenon and its consequences.

HIGHLIGHTS

High-frequency assessment of air and water quality at a concentration animal feeding operation during wastewater application to spray fields

Air and water quality at a concentrated animal feeding operation (CAFO) in Eastern North Carolina that uses a covered lagoon and anaerobic digester was evaluated for 2 weeks in August 2020. Real-time PM_2.5 mass concentrations were determined using a reference ADR-1500 nephelometer and high-frequency measurements of dissolved inorganic nitrogen (DIN) were evaluated using autonomously logging sensors. Air and water quality parameters were assessed before, during and after wastewater from the lagoon was irrigated onto adjacent spray fields. Reference measurements were conducted alongside a HOBO weather station to collect real-time wind speed and direction, temperature, and humidity measurements. PM_2.5 concentrations varied between 0 and 159 μg/m³ with an average concentration of 11 μg/m³, below EPA standard for secondary aerosols of 15 μg/m³. Higher PM_2.5 concentrations were observed when wind originated from swine barns but not from covered lagoons. Water quality data showed that DIN concentrations downgradient from the CAFO were elevated relative to upstream concentrations. A groundwater seep that drains a spray field contained the highest average DIN concentration (31.0 ± 12.8 mg L^-1), which was 25 times greater than upstream DIN concentrations (1.2 ± 0.8 mg L^-1). Average DIN concentration at the downstream station was lower than the seep concentration (8.6 ± 16.2 mg L^-1), but approximately 8 times greater than upstream. Air quality data show that the lagoon cover was effective at mitigating air quality degradation, whereas DIN concentrations in water were similar to previous studies on CAFOs using open lagoons. In addition, air and water quality parameters were significantly (p < 0.001) higher after irrigation, indicating possible influence due to ammonia and nitrate elevation. Additional research is needed to compare high-frequency data collected from swine CAFOs using capped and uncapped lagoon systems to better understand spatiotemporal air and water quality trends of this practice.

Epidemiologic Associations Vary Between Tetracycline and Fluoroquinolone Resistant Campylobacter jejuni Infections

Campylobacter jejuni is the leading cause of bacterial gastroenteritis and antibiotic resistant C. jejuni are a serious threat to public health. Herein, we sought to evaluate trends in C. jejuni infections, quantify resistance frequencies, and identify epidemiological factors associated with infection. Campylobacter jejuni isolates (n = 214) were collected from patients via an active surveillance system at four metropolitan hospitals in Michigan between 2011 and 2014. The minimum inhibitory concentration for nine antibiotics was determined using microbroth dilution, while demographic and clinical data were used for the univariate and multivariate analyses. Over the 4-year period, a significant increase in the recovery of C. jejuni was observed (p ≤ 0.0001). Differences in infection rates were observed by hospital and several factors were linked to more severe disease. Patients residing in urban areas, for instance, were significantly more likely to be hospitalized than rural residents as were patients over 40 years of age and those self-identifying as non-White, highlighting potential disparities in disease outcomes. Among the 214 C. jejuni isolates, 135 (63.1%) were resistant to at least one antibiotic. Resistance was observed for all nine antibiotics tested yielding 11 distinct resistance phenotypes. Tetracycline resistance predominated (n = 120; 56.1%) followed by resistance to ciprofloxacin (n = 49; 22.9%), which increased from 15.6% in 2011 to 25.0% in 2014. Resistance to two antibiotic classes was observed in 38 (17.8%) isolates, while multidrug resistance, or resistance to three or more classes, was observed in four (1.9%). Notably, patients with ciprofloxacin resistant infections were more likely to report traveling in the past month (Odds Ratio (OR): 3.0; 95% confidence interval (CI): 1.37, 6.68) and international travel (OR: 9.8; 95% CI: 3.69, 26.09). Relative to patients with only tetracycline resistant infections, those with ciprofloxacin resistance were more likely to travel internationally, be hospitalized and have an infection during the fall or summer. Together, these findings show increasing rates of infection and resistance and highlight specific factors that impact both outcomes. Enhancing understanding of factors linked to C. jejuni resistance and more severe infections is critical for disease prevention, particularly since many clinical laboratories have switched to the use of culture-independent tests for the detection of Campylobacter.

Acute Bacterial Gastroenteritis

Acute bacterial gastroenteritis is among the most common infections worldwide, with millions of infections annually in the United States. Much of the illness is foodborne, occurring as both sporadic cases and large multistate outbreaks. Pathogen evolution through genetic exchange of virulence traits and antibiotic resistance determinants poses challenges for empiric therapy. Culture-independent diagnostic tests in clinical laboratories afford rapid diagnosis and expanded identification of pathogens. However, cultures remain important to generate sensitivity data and strain archiving for outbreak investigations. Most infections are self-limited, permitting judicious selection of antibiotic use in more severe forms of illness.

Campylobacter jejuni Antimicrobial Resistance Profiles and Mechanisms Determined Using a Raman Spectroscopy-Based Metabolomic Approach

Rapid identification of antimicrobial resistance (AMR) profiles and mechanisms is critical for clinical management and drug development. However, the current AMR detection approaches take up to 48 h to obtain a result. Here, we demonstrate a Raman spectroscopy-based metabolomic approach to rapidly determine the AMR profile of Campylobacter jejuni, a major cause of foodborne gastroenteritis worldwide. C. jejuni isolates with susceptible and resistant traits to ampicillin and tetracycline were subjected to different antibiotic concentrations for 5 h, followed by Raman spectral collection and chemometric analysis (i.e., second-derivative transformation analysis, hierarchical clustering analysis [HCA], and principal-component analysis [PCA]). The MICs obtained by Raman-2nd derivative transformation agreed with the reference agar dilution method for all isolates. The AMR profile of C. jejuni was accurately classified by Raman-HCA after treating bacteria with antibiotics at clinical susceptible and resistant breakpoints. According to PCA loading plots, susceptible and resistant strains showed different Raman metabolomic patterns for antibiotics. Ampicillin-resistant isolates had distinctive Raman signatures of peptidoglycan, which is related to cell wall synthesis. The ratio of saturated to unsaturated fatty acids in the lipid membrane layer of ampicillin-resistant isolates was higher than in susceptible ones, indicating more rigid envelope structure under ampicillin treatment. In comparison, tetracycline-resistant isolates exhibited prominent Raman spectral features associated with proteins and nucleic acids, demonstrating more active protein synthesis than susceptible strains with the presence of tetracycline. Taken together, Raman spectroscopy is a powerful metabolic fingerprinting technique for simultaneously revealing the AMR profiles and mechanisms of foodborne pathogens. IMPORTANCE Metabolism plays the central role in bacteria to mediate the early response against antibiotics and demonstrate antimicrobial resistance (AMR). Understanding the whole-cell metabolite profiles gives rise to a more complete AMR mechanism insight. In this study, we have applied Raman spectroscopy and chemometrics to achieve a rapid, accurate, and easy-to-operate investigation of bacterial AMR profiles and mechanisms. Raman spectroscopy reduced the analysis time by an order of magnitude to obtain the same results achieved through traditional culture-based antimicrobial susceptibility approaches. It offers great benefits as a high-throughput screening method in food chain surveillance and clinical diagnostics. Meanwhile, the AMR mechanisms toward two representative antibiotic classes, namely, ampicillin and tetracycline, were revealed by Raman spectroscopy at the metabolome level. This approach is based on bacterial phenotypic responses to antibiotics, providing information complementary to that obtained by conventional genetic methods such as genome sequencing. The knowledge obtained from Raman metabolomic data can be used in drug discovery and pathogen intervention.

Abundance of Mobilized Colistin Resistance Gene (mcr-1) in Commensal Escherichia coli from Diverse Sources

Aims: Antimicrobial resistance (AMR) spreads not only by pathogenic but also by commensal bacteria, and the latter can become a reservoir for resistance genes. This study was aimed to investigate the AMR patterns along with the presence of mobilized colistin resistance (mcr) genes in commensal Escherichia coli circulating in chickens, farm environments, street foods, and human patients. Materials and Methods: By a cross-sectional survey, isolates obtained from 530 samples were tested for their AMR profiles against 9 antimicrobials. Minimum inhibitory concentration (MIC) of the phenotypically colistin-resistant isolates was determined and screened for a set of mcr genes followed by sequencing of mcr-1 gene in the multidrug-resistant (MDR) isolates. Results: A total of 313 E. coli strains were isolated and confirmed by polymerase chain reaction. Antimicrobial susceptibility testing revealed that about 98% (confidence interval [95% CI] 95-99) of the isolates were MDR, and 58% (95% CI 52-63) isolates exhibited resistance to colistin. MIC values of colistin against the isolates ranged from 4 to 64 mg/L. Except for human patients, 20.4% colistin-resistant isolates from other sources of isolation had mcr-1 gene. Conclusions: There is abundance of commensal MDR E. coli strains with the acquisition of mcr-1 gene circulating in chickens and farm environments in Bangladesh.

Possible reservoirs of thermotolerant Campylobacter at the farm between rearing periods and after the use of enrofloxacin as a therapeutic treatment

Campylobacteriosis is a zoonosis and the most frequent cause of food-borne bacterial enteritis in humans. C. jejuni and C. coli are the most common species implicated in campylobacteriosis. Broilers and their products are considered the most important food sources of human infections. The aim of the present study was to evaluate the presence of thermotolerant Campylobacter in different reservoirs at the farm, and the permanence of this pathogen during four consecutive rearing periods. The samples were taken from the same house farm in the downtime period and during the last week of broiler rearing, prior to their slaughter during four consecutive cycles. Different reservoirs as potential sources of Campylobacter were analysed. The prevalence of Campylobacter in vectors was 23% in A. diaperinus larvae, 20% in wild birds, 13% in A. diaperinus adults, and 9% in flies; as regards fomites, the prevalence was 50% in workers' boots, 27% in litter, and 21% in feed, while in broilers it was 80%. Campylobacter jejuni was the most detected species (51%) in the samples analysed. In addition, some Campylobacter genotypes persisted in the house farm throughout consecutive rearing periods, indicating that those strains remain during downtime periods. However, our study could not identify the Campylobacter sources in the downtime periods because all the samples were negative for Campylobacter isolation. In addition, a remarkable finding was the effect of the use of enrofloxacin (as a necessary clinical intervention for flock health) in cycle 3 on the Campylobacter population. No Campylobacter could be isolated after that clinic treatment. Afterwards, we found a greater proportion of C. coli isolates, and the genotypes of those isolates were different from the genotypes found in the previous rearing periods. In conclusion, the effect of the use of enrofloxacin during the rearing period changed the Campylobacter species proportion, and this finding is particularly interesting for further evaluation. Furthermore, more studies should be conducted with the aim of detecting the Campylobacter sources between rearing periods.

Effect of antimicrobial use and production system on Campylobacter spp., Staphylococcus spp. and Salmonella spp. resistance in Spanish swine: A cross-sectional study

Antimicrobial resistance is a worldwide public health threat; hence, current trends tend to reduce antimicrobial use in food-producing animals and to monitor resistance in primary production. This study aimed at evaluating the impact of antimicrobial use and production system on swine farms in the antimicrobial resistance of Campylobacter, Salmonella and Staphylococcus, the main zoonotic pathogens in pig herds, in order to assess their potential value as sentinel microorganisms in antimicrobial resistance surveillance schemes. A total of 37 Spanish swine farms, 18 intensive and 19 organic/extensive farms, were included in the study. The antimicrobial resistance of 104 Campylobacter, 84 Staphylococcus and 17 Salmonella isolates was evaluated using Sensititre plates following the EUCAST guidelines. Mixed-effects logistic regression was used to evaluate the influence of production system and antimicrobial use in resistant and multidrug-resistant (MDR) phenotypes to the antimicrobials tested. The results showed that antimicrobial use was higher (p < .001) on intensive farms than on organic/extensive farms. MDR in Campylobacter and Staphylococcus was lower on organic/extensive farms (OR < .01p < .001). Antimicrobial resistance in Campylobacter and Staphylococcus isolates was, also for most of the antimicrobials studied, significantly higher in intensive than organic/extensive pig herds. Tetracycline resistance was associated with total antimicrobial consumption in both microbial species (p < .05), and some cross-associations between distinct antimicrobial substances were established, for instance resistance to erythromycin was associated with macrolide and phenicol consumption. No significant associations could be established for Salmonella isolates. The results demonstrate the link between antimicrobial consumption and resistance in zoonotic bacteria and evidence the potential value of using Campylobacter and Staphylococcus species in monitoring activities aimed at determining the impact of antimicrobials use/reduction on the occurrence and spread of antimicrobial resistance.

Multilocus Sequence Types and Antimicrobial Resistance of Campylobacter jejuni and C. coli Isolates of Human Patients From Beijing, China, 2017-2018

Campylobacter species are zoonotic pathogens and the leading cause of bacterial enteritis worldwide. With the increase of antimicrobial resistance to fluoroquinolones and macrolides, they have been identified by the World Health Organization (WHO) as high-priority antimicrobial-resistant pathogens. There is currently little known about the prevalence and antimicrobial resistance characteristics of Campylobacter species in Beijing. In this study, we performed a 2-year surveillance of Campylobacter in Beijing, China. We used multilocus sequence typing (MLST) and antimicrobial susceptibility testing to analyze 236 Campylobacter isolates recovered from 230 clinical infectious cases in Beijing between 2017 and 2018. The Campylobacter isolation rate in diarrhea patients was 7.81%, with higher isolation rates in male patients than female patients and in autumn compared with other seasons. We identified 125 sequence types (STs) of 23 cloning complexes (CCs) among the 236 isolates, including four new alleles and 19 new STs. The most commonly isolated STs of Campylobacter jejuni were ST-22 and ST-760 (4.50%), and the most commonly isolated ST of Campylobacter coli was ST-9227 (16.67%). We also compared our isolates with clinical Campylobacter isolates from other countries in Asia, CC-353 of Campylobacter coli was found in eight countries, CC-1034 and CC-1287 of Campylobacter coli were found only in China. All C. jejuni isolates were resistant to at least one antimicrobial. C. jejuni showed the highest rate of resistance toward ciprofloxacin (94.50%), followed by tetracycline (93.50%), and nalidixic acid (92.00%), while C. coli showed highest resistance toward ciprofloxacin (94.44%) and tetracycline (94.44%) followed by nalidixic acid (88.89%). The most commonly observed MDR combination of C. jejuni were quinolone, phenicol and tetracycline (11.50%), while the most commonly observed MDR combination of C. coli were macrolide, quinolone, phenicol, tetracycline and lincosamide (30.56%). Surveillance of molecular characterization will provide important information for prevention of Campylobacter infection. This study enhances insight into Campylobacter infections in diarrheal patients, with relevance for treatment regimens in Beijing.

Antibiotics in Food Chain: The Consequences for Antibiotic Resistance

Antibiotics have been used as essential therapeutics for nearly 100 years and, increasingly, as a preventive agent in the agricultural and animal industry. Continuous use and misuse of antibiotics have provoked the development of antibiotic resistant bacteria that progressively increased mortality from multidrug-resistant bacterial infections, thereby posing a tremendous threat to public health. The goal of our review is to advance the understanding of mechanisms of dissemination and the development of antibiotic resistance genes in the context of nutrition and related clinical, agricultural, veterinary, and environmental settings. We conclude with an overview of alternative strategies, including probiotics, essential oils, vaccines, and antibodies, as primary or adjunct preventive antimicrobial measures or therapies against multidrug-resistant bacterial infections. The solution for antibiotic resistance will require comprehensive and incessant efforts of policymakers in agriculture along with the development of alternative therapeutics by experts in diverse fields of microbiology, biochemistry, clinical research, genetic, and computational engineering.

Antimicrobial Resistance of Human Campylobacter Species Infections in Saskatchewan, Canada (1999-2006): A Historical Provincial Collection of All Reported Cases

To describe a historical baseline of antimicrobial resistance (AMR) profiles for human clinical Campylobacter species isolates obtained by laboratory surveillance in the province of Saskatchewan from 1999 to 2006; to determine if there were differences in resistance between Campylobacter jejuni and Campylobacter coli; and to determine if there were changes in the annual resistance levels in the two species. One thousand three hundred seventy-eight Campylobacter isolates were subjected to antimicrobial susceptibility testing using the E-test method. Annual resistance levels in C. jejuni and C. coli were compared using logistic regression models. One thousand two hundred (87.1%) isolates were C. jejuni and 129 (9.4%) were C. coli. Resistance in C. jejuni isolates included ciprofloxacin (CIP: 9.4%), erythromycin (ERY: 0.5%), and tetracycline (33.3%). CIP resistance in C. jejuni was higher in 1999 (15.5%, odds ratio [OR] = 3.96, p = 0.01), 2000 (12.7%, OR = 3.10, p = 0.01), 2005 (10.2%, OR = 2.47, p = 0.05), and 2006 (13.0%, OR = 3.22, p = 0.01) compared with 2004 (4.4%). C. coli had significantly higher CIP resistance (15.5%, OR = 1.78, p = 0.03), ERY resistance (13.2%, OR = 60.12, p < 0.01), multidrug resistance (2.3%, OR = 36.29, p < 0.01), and CIP-ERY resistance (3.1%, OR = 50.23, p < 0.01) compared with C. jejuni. This represents the first and most current report of AMR of the collective human Campylobacter isolates from a province in Canada and provides a baseline against which current and future resistance patterns can be compared. Fluoroquinolone resistance in C. jejuni isolates fluctuated from 1999 to 2006, including an increased prevalence in 2005-2006, while macrolide/lincosamide resistance remained very low. Human clinical C. jejuni isolates from Saskatchewan demonstrated resistance to multiple antimicrobials but had significantly less fluoroquinolone and macrolide resistance than C. coli isolates.

Prevalence, Antimicrobial Resistance, and Molecular Typing of Thermophilic Campylobacter Spp. in a Greek Poultry Slaughterhouse

Campylobacter species are one of the leading causes of foodborne disease. Poultry is a major reservoir and source of its transmission to humans. The aim of this study was to estimate the prevalence and antimicrobial resistance of Campylobacter spp. isolated from chicken carcasses, the environment, and processing equipment of a poultry slaughterhouse in Greece, to identify the dominant Campylobacter species and to determine if there are clonal relationships among the isolates. Fifty poultry samples and 25 environmental samples were examined using microbial cultures and PCR. Forty-nine of 50 poultry samples (98%) were found to be positive for Campylobacter spp. The environment of the slaughterhouse was also found to be significantly contaminated with Campylobacter spp. Thirty-seven isolates were found to be susceptible to all antimicrobials tested (56.1%) and 29 isolates showed resistance to at least two of the antimicrobials tested (43.9%). We observed 24 different PFGE-types among the 53 isolates with 14 of them isolated only once, while five PFGE-types were represented by two isolates. The remaining 29 isolates were represented by five PFGE-types each consisting of three to 12 isolates. Regarding the relationship of the PFGE types and corresponding resistance profiles, all strains of each PFGE-type shared the same antimicrobial resistance profile. This study reports evidence for Campylobacter spp. cross-contamination among broiler carcasses in a Greek slaughterhouse.

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

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

Differentiating Epidemic from Endemic or Sporadic Infectious Disease Occurrence

One important scope of work of epidemiology is the investigation of infectious diseases that cluster in time and place. Clusters of infectious disease may represent outbreaks or epidemics in which the cases share in common a point source exposure or an infectious agent in a chain of transmission pathways. Investigations of outbreaks of an illness can facilitate identification of a source, risk, or cause of the illness. However, most infectious disease episodes occur not as part of any apparent outbreaks but as sporadic infections. Multiple sporadic infections that occur steadily in time and place are referred to as endemic disease. How does one investigate sources and risk factors for sporadic or endemic infections? As part of the Microbiology Spectrum Curated Collection: Advances in Molecular Epidemiology of Infectious Diseases, this review discusses limitations of traditional approaches and advantages of molecular epidemiology approaches to investigate sporadic and endemic infections. Using specific examples, the discussions show that most sporadic infections are actually part of unrecognized outbreaks and that what appears to be endemic disease occurrence is actually comprised of multiple small outbreaks. These molecular epidemiologic investigations have unmasked modes of transmission of infectious agents not known to cause outbreaks. They have also raised questions about the traditional ways to measure incidence and assess sources of drug-resistant infections in community settings. The discoveries made by the application of molecular microbiology methods in epidemiologic investigations have led to creation of new public health intervention strategies that have not been previously considered. *This article is part of a curated collection.

Growth in the presence of specific antibiotics induces biofilm formation by a Campylobacter jejuni strain sensitive to them but not in resistant strains

OBJECTIVE

Campylobacter jejuni (C. jejuni) are among the most frequently identified bacteria associated with human gastroenteritis worldwide. Exposure to antibiotics may induce or inhibit biofilm formation in some bacterial species. Little work has been reported on the influence of antibiotics on biofilm formation by C. jejuni.

METHODS

This study investigated the effect of six different classes of antibiotics with different modes of action (ampicillin, ciprofloxacin, erythromycin, nalidixic acid, rifampicin and tetracycline) on biofilm formation in vitro by seven C. jejuni from poultry with different antibiotic resistance profiles.

RESULTS

The results indicated that in the presence of most of the tested antibiotics, biofilm formation by C. jejuni strains, which are resistant to them, was reduced but biofilm formation in sensitive strains was increased.

CONCLUSION

The ability of certain antibiotics to induce biofilm formation by a tested C. jejuni strain is of concern, with respect to the effective control of disease caused by this pathogen; however, further work is required to confirm how widespread this feature is.

History and Current Use of Antimicrobial Drugs in Veterinary Medicine

This chapter briefly reviews the history and current use of antimicrobials in animals, with a focus on food animals in the more economically developed countries. It identifies some of the differences between human medical and food animal use, particularly in growth promotional and "subtherapeutic" use of medically-important antibiotics in animals. The public health impact of the extensive use of antibiotics in food animals for these purposes, differences internationally in such usage, and the major changes in current practices now underway in agricultural use are summarized. The emerging framing of the dimensions of antimicrobial resistance within a "One Health" framework is focusing global efforts to address the antimicrobial resistance crisis in a collaborative manner. The rapidly evolving development and application of practices of antimicrobial stewardship in animal is a critical part of the huge global effort to address antimicrobial resistance. The outcome is still uncertain.

Comparison of Mismatch Amplification Mutation Assay PCR and PCR-Restriction Fragment Length Polymorphism for Detection of Major Mutations in gyrA and parC of Escherichia coli Associated with Fluoroquinolone Resistance

Fluoroquinolones are the drug of choice for most of the infections caused by Escherichia coli, and their indiscriminate use has resulted in increased selective pressure for antibiotic resistance. At present, sequencing is the only reliable and direct technique to detect mutations in the quinolone resistance determining region (QRDR). In this study, a rapid and reliable mismatch amplification mutation assay (MAMA) PCR to detect mutations in the QRDR was evaluated and compared to PCR-restriction fragment length polymorphism (PCR-RFLP). One hundred one clinical isolates of E. coli were subjected to MAMA-PCR and PCR-RFLP to detect QRDR mutations. Overall, 92 (91.08%) resistant isolates harbored a point mutation of S83L in gyrA. Double mutations in gyrA were also detected in 45 (44.55%) isolates. Similarly, 41 (40.59%) isolates possessed a point mutation at parC 80, and 25 (24.75%) isolates possessed a point mutation at parC 84. Additionally, MAMA-PCR-the first of its kind-was also standardized to detect mutations in regions gyrB 447 and parE 416, although no mutations were detected in these regions. The rapid and sensitive MAMA-PCR method evaluated in this study would be helpful in exploring the underlying mechanism of fluoroquinolone resistance to enhance control strategies.

Antimicrobial Resistance in the Food Chain in the European Union

Consumers require safety foods but without losing enough supply and low prices. Food concerns about antimicrobial residues and antimicrobial-resistant (AMR) bacteria are not usually appropriately separated and could be perceived as the same problem. The monitoring of residues of antimicrobials in animal food is well established at different levels (farm, slaughterhouse, and industry), and it is preceded by the legislation of veterinary medicines where maximum residues limits are required for medicines to be used in food animal. Following the strategy of the World Health Organization, one of the proposed measures consists in controlling the use of critical antibiotics. The European Union surveillance program currently includes the animal species with the highest meat production (pigs, chickens, turkeys, and cattle) and the food derived from them, investigating antimicrobial resistance of zoonotic (Salmonella and Campylobacter) and indicator (Escherichia coli and enterococci) bacteria. AMR mechanisms encoded by genes have a greater impact on transfer than mutations. Sometimes these genes are found in mobile genetic elements such as plasmids, transposons, or integrons, capable of passing from one bacterium to another by horizontal transfer. It is important to know that depending on how the resistance mechanism is transferred, the power of dissemination is different. By vertical transfer of the resistance gene, whatever its origin, will be transmitted to the following generations. In the case of horizontal transfer, the resistance gene moves to neighboring bacteria and therefore the range of resistance can be much greater.

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.

Acute Infectious Diarrhoea in Adults: Identifying Clinical Parameters Associated with Specific Pathogens

Introduction

Infectious diarrhoea may be caused by viral, bacterial or protozoan agents. The objective of this study was to explore the possibility of correlating presenting clinical and demographic features with the specific types of stool pathogens subsequently identified.

Materials & Methods

A retrospective study was performed in the setting of an Accident & Emergency (A&E) department of an urban acute-care hospital in Hong Kong. The inclusion criteria were adults (age ≥16); presentation with features of acute infectious diarrhoea; treated as out-patients with or without observation; and with stool cultures requested from A&E. All consecutive culture-positive cases (n=130) satisfying the above criteria were included. The control-group (n=119) consisted of a random sample of culture-negative cases during the same study period. For each of the six pathogens identified, statistical analyses were performed to compare differences in clinical features amongst three groups: (i) cases positive for the specific pathogen; (ii) cases positive for other pathogens; and (iii) cases with negative culture.

Results

Salmonella was associated with significantly higher body temperatures at presentation. Vibrio parahaemolyticus (VP) was associated with a significantly shorter duration of diarrhoea and of abdominal pain at presentation. Other variables were not helpful in predicting the type of stool pathogen.

Conclusion

In patients presenting with acute infectious diarrhoea in an A&E setting in Hong Kong, Salmonella and VP may be suspected according to the clinical features identified in this study.

National Antimicrobial Resistance Monitoring System: Two Decades of Advancing Public Health Through Integrated Surveillance of Antimicrobial Resistance

Drug-resistant bacterial infections pose a serious and growing public health threat globally. In this review, we describe the role of the National Antimicrobial Resistance Monitoring System (NARMS) in providing data that help address the resistance problem and show how such a program can have broad positive impacts on public health. NARMS was formed two decades ago to help assess the consequences to human health arising from the use of antimicrobial drugs in food animal production in the United States. A collaboration among the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, the United States Department of Agriculture, and state and local health departments, NARMS uses an integrated "One Health" approach to monitor antimicrobial resistance in enteric bacteria from humans, retail meat, and food animals. NARMS has adapted to changing needs and threats by expanding surveillance catchment areas, examining new isolate sources, adding bacteria, adjusting sampling schemes, and modifying antimicrobial agents tested. NARMS data are not only essential for ensuring that antimicrobial drugs approved for food animals are used in ways that are safe for human health but they also help address broader food safety priorities. NARMS surveillance, applied research studies, and outbreak isolate testing provide data on the emergence of drug-resistant enteric bacteria; genetic mechanisms underlying resistance; movement of bacterial populations among humans, food, and food animals; and sources and outcomes of resistant and susceptible infections. These data can be used to guide and evaluate the impact of science-based policies, regulatory actions, antimicrobial stewardship initiatives, and other public health efforts aimed at preserving drug effectiveness, improving patient outcomes, and preventing infections. Many improvements have been made to NARMS over time and the program will continue to adapt to address emerging resistance threats, changes in clinical diagnostic practices, and new technologies, such as whole genome sequencing.

Zoonotic Potential and Antibiotic Resistance of Escherichia coli in Neonatal Calves in Uruguay

Escherichia coli is one of the main etiological agents of neonatal calf diarrhea (NCD). The objective of this study was to assess the presence of virulence genes, genetic diversity, and antibiotic resistance mechanisms in E. coli associated with NCD in Uruguay. PCR was used to assess the presence of intimin, Shiga-like toxin, and stable and labile enterotoxin genes. Resistance to fluoroquinolones and oxyimino-cephalosporins was estimated on Müller-Hinton agar plates. Further antibiotic disc-diffusion tests were performed to assess bacterial multi-resistance. The presence of PMQR, ESBL, MCR-1, and integron genes was evaluated. Isolates were typed using ERIC-PCR, and 20 were selected for MLST, adhesion to Hep-2 cells, in vitro biofilm formation, and eukaryotic cytotoxicity. The prevalence of ETEC genes was lower than 3% in each case (estA and elt). Six isolates were EPEC (eae+) and 2 were EHEC/STEC (eae+/stx1+). The results of a diversity analysis showed high genetic heterogenicity among isolates. Additionally, different sequence types, including ST10, ST21, and ST69, were assigned to selected isolates. Thirty-six percent (96/264) of the isolates were fluoroquinolone-resistant, with 61/96 (63.5%) being multidrug-resistant. Additionally, 6 were oxyimino-cephalosporin-resistant. The qnrB, qnrS1, and bla_CTX-M-14 genes were detected, whereas no isolates carried the mcr-1 gene. Isolates had the ability to adhere to Hep-2 cells and form biofilms. Only 1 isolate expressed toxins in vitro. E. coli from NCD cases in Uruguay are very diverse, potentially virulent, and may interact with eukaryotic cells. Zoonotic potential, together with resistance traits and the presence of horizontal transfer mechanisms, may play a significant role in infections caused by these microorganisms.

Diversity of Antimicrobial Resistance Phenotypes in Salmonella Isolated from Commercial Poultry Farms

Salmonella remains the leading cause of foodborne illness in the United States, and the dissemination of drug-resistant Salmonellae through the food chain has important implications for treatment failure of salmonellosis. We investigated the ecology of Salmonella in integrated broiler production in order to understand the flow of antibiotic susceptible and resistant strains within this system. Data were analyzed from a retrospective study focused on antimicrobial resistant Salmonella recovered from commercial broiler chicken farms conducted during the initial years of the US FDA's foray into retail meat surveillance by the National Antimicrobial Resistance Monitoring System (NARMS). Sixty-three percentage of Salmonella were pan-susceptible to a panel of 19 antimicrobials used by the NARMS program. Twenty-five antimicrobial resistance phenotypes were observed in Salmonella isolated from two broiler chicken farms. However, Salmonella displaying resistance to streptomycin, alone, and in combination with other antibiotics was the most prevalent (36.3%) antimicrobial resistance phenotype observed. Resistance to streptomycin and sulfadimethoxine appeared to be linked to the transposon, Tn21. Combinations of resistance against streptomycin, gentamicin, sulfadimethoxine, trimethoprim, and tetracycline were observed for a variety of Salmonella enterica serovars and genetic types as defined by pulsed-field gel electrophoresis. There were within and between farm differences in the antibiotic susceptibilities of Salmonella and some of these differences were linked to specific serovars. However, farm differences were not linked to antibiotic usage. Analysis of the temporal and spatial distribution of the endemic Salmonella serovars on these farms suggests that preventing vertical transmission of antibiotic-resistant Salmonella would reduce carcass contamination with antibiotic-resistant Salmonella and subsequently human risk exposure.

The Food Production Environment and the Development of Antimicrobial Resistance in Human Pathogens of Animal Origin

Food-borne pathogens are a serious human health concern worldwide, and the emergence of antibiotic-resistant food pathogens has further confounded this problem. Once-highly-efficacious antibiotics are gradually becoming ineffective against many important pathogens, resulting in severe treatment crises. Among several reasons for the development and spread of antimicrobial resistance, their overuse in animal food production systems for purposes other than treatment of infections is prominent. Many pathogens of animals are zoonotic, and therefore any development of resistance in pathogens associated with food animals can spread to humans through the food chain. Human infections by antibiotic-resistant pathogens such as Campylobacter spp., Salmonella spp., Escherichia coli and Staphylococcus aureus are increasing. Considering the human health risk due to emerging antibiotic resistance in food animal-associated bacteria, many countries have banned the use of antibiotic growth promoters and the application in animals of antibiotics critically important in human medicine. Concerted global efforts are necessary to minimize the use of antimicrobials in food animals in order to control the development of antibiotic resistance in these systems and their spread to humans via food and water.

Epidemiological relationships of Campylobacter jejuni strains isolated from humans and chickens in South Korea

Thirty-nine human isolates of Campylobacter jejuni obtained from a national university hospital during 2007-2010 and 38 chicken isolates of C. jejuni were collected from poultry farms during 2009-2010 in South Korea were used in this study. Campylobacter genomic species and virulence-associated genes were identified by PCR. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to compare their genetic relationships. All isolates were highly resistant to ciprofloxacin, nalidixic acid, and tetracycline. Of all isolates tested, over 94% contained seven virulence associated genes (flaA, cadF, racR, dnaJ, cdtA, cdtB, and cdtC). All isolates were classified into 39 types by PFGE clustering with 90% similarity. Some chicken isolates were incorporated into some PFGE types of human isolates. MLST analysis for the 39 human isolates and 38 chicken isolates resulted in 14 and 23 sequence types (STs), respectively, of which 10 STs were new. STs overlapped in both chicken and human isolates included ST-21, ST-48, ST-50, ST-51, and ST-354, of which ST-21 was the predominant ST in both human and chicken isolates. Through combined analysis of PFGE types and STs, three chicken isolates were clonally related to the three human isolates associated with food poisoning (VII-ST-48, XXII-ST-354, and XXVIII-ST-51). They were derived from geographically same or distinct districts. Remarkably, clonal spread of food poisoning pathogens between animals and humans was confirmed by population genetic analysis. Consequently, contamination of campylobacters with quinolone resistance and potential virulence genes in poultry production and consumption may increase the risk of infections in humans.

Antibiotics: practice and opinions of Cambodian commercial farmers, animal feed retailers and veterinarians

BACKGROUND

Cambodia has reported multidrug resistant bacteria in poultry, similar to other countries in the region. We visited commercial food animal farms to explore opinions and antibiotic practices on the farms.

METHODS

We used individual in-depth qualitative interviews with 16 commercial farmers, four feed retailers and nine veterinarians from food animal industry and government offices from the southwestern region of Phnom Penh. Transcribed interviews were thematically analysed.

RESULTS

Widespread antibiotic use occurred on all farms and was driven by four facilitators: belief that antibiotics were necessary for animal raising, limited knowledge, unrestricted antibiotic access, and weak monitoring and control systems. "If we treat ducks for two days and they aren't cured we change to human drugs. We cocktail 10 tablets of this, 10 tablets of that and 20 tablets of this one. Altogether 200 tablets are mixed in 100 or 200 L of water for the ducks to drink. No one taught me, just my experiences." Antibiotics were believed to be necessary for disease prevention. "On the first day when we bring in the chicks, we let them drink Enro [enrofloxacin] and vitamins to make them resist to the weather. We place them in the house and there are some bacteria in the environment. When they are newly arrived, we have to give them feed. So we're afraid they get diarrhea when they eat feed, we have to use Enro." All farmers used pre-mixed feed that veterinarians and feed retailers acknowledged contained antibiotics but not all listed the antibiotics. Farmers viewed pre-mixed feed as a necessary 'feed supplement' for growth promotion. "….The fatten supplement is mixed in feed. Pigs aren't growing well unless I use the supplement." Farmers and veterinarians were concerned that 'antibiotic residuals' in animal meat could harm human health. But they did not link this with antibiotic resistance.

CONCLUSIONS

Antibiotic use in food animals was widespread and uncontrolled. Farmers focused on the benefits of food animal production rather than concerns about the consequences of antibiotic use. Therefore, education for prudent use of antibiotics in food animals and regulations are urgently needed in food animal farming in Cambodia.

Cultivation of an Adaptive Domestic Network for Surveillance and Evaluation of Emerging Infections

Accomplishments of this program have provided numerous dividends and might benefit areas outside infectious diseases.

Ecological Dynamics of Campylobacter in Integrated Mixed Crop-Livestock Farms and Its Prevalence and Survival Ability in Post-Harvest Products

This study investigated the ecological distribution of zoonotic bacterial pathogen, Campylobacter, in mixed crop-livestock (MCL) farms compared to conventional farms and their products at pre- and post-harvest levels. A total of 222 Campylobacter isolates were identified. At pre-harvest level, a total of 1287 samples from seven MCL farms, four conventional poultry farms, four organic produce-only and five conventional produce-only farms from Maryland and the DC metropolitan area were analysed from 2012 to 2014. Campylobacter was detected in 11.16% and 3.6% of MCL and conventional farm samples, respectively, but none from produce-only farm samples. Tetracycline resistance was observed in 51.02% of MCL farm isolates but none among conventional farm isolates. For post-harvest analysis, a total of 1281 food products from seven farmers markets, three organic retail supermarkets and three conventional retail supermarkets were collected from the same area. Campylobacter was isolated in 87.5%, 71.43% and 33.33% of whole chicken carcasses in farmers markets, organic and conventional retail supermarkets, respectively. No Campylobacter was detected in post-harvest produce samples due in part to the inability of Campylobacter to survive in absence of sufficient water activity. Overall, this study reveals public health concerns regarding the MCL farm environment and their products that are sold in retail and farmers markets.

Antimicrobial Susceptibility Profiles of Human Campylobacter jejuni Isolates and Association with Phylogenetic Lineages

Campylobacter jejuni is a zoonotic pathogen and the most common bacterial cause of human gastroenteritis worldwide. With the increase of antibiotic resistance to fluoroquinolones and macrolides, the drugs of choice for treatment, C. jejuni was recently classified as a serious antimicrobial resistant threat. Here, we characterized 94 C. jejuni isolates collected from patients at four Michigan hospitals in 2011 and 2012 to determine the frequency of resistance and association with phylogenetic lineages. The prevalence of resistance to fluoroquinolones (19.1%) and macrolides (2.1%) in this subset of C. jejuni isolates from Michigan was similar to national reports. High frequencies of fluoroquinolone-resistant C. jejuni isolates, however, were recovered from patients with a history of foreign travel. A high proportion of these resistant isolates were classified as multilocus sequence type (ST)-464, a fluoroquinolone-resistant lineage that recently emerged in Europe. A significantly higher prevalence of tetracycline-resistant C. jejuni was also found in Michigan and resistant isolates were more likely to represent ST-982, which has been previously recovered from ruminants and the environment in the U.S. Notably, patients with tetracycline-resistant C. jejuni infections were more likely to have contact with cattle. These outcomes prompt the need to monitor the dissemination and diversification of imported fluoroquinolone-resistant C. jejuni strains and to investigate the molecular epidemiology of C. jejuni recovered from cattle and farm environments to guide mitigation strategies.

Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance

Aquaculture uses hundreds of tonnes of antimicrobials annually to prevent and treat bacterial infection. The passage of these antimicrobials into the aquatic environment selects for resistant bacteria and resistance genes and stimulates bacterial mutation, recombination, and horizontal gene transfer. The potential bridging of aquatic and human pathogen resistomes leads to emergence of new antimicrobial-resistant bacteria and global dissemination of them and their antimicrobial resistance genes into animal and human populations. Efforts to prevent antimicrobial overuse in aquaculture must include education of all stakeholders about its detrimental effects on the health of fish, human beings, and the aquatic ecosystem (the notion of One Health), and encouragement of environmentally friendly measures of disease prevention, including vaccines, probiotics, and bacteriophages. Adoption of these measures is a crucial supplement to efforts dealing with antimicrobial resistance by developing new therapeutic agents, if headway is to be made against the increasing problem of antimicrobial resistance in human and veterinary medicine.

Clinical implications of reduced susceptibility to fluoroquinolones in paediatric Shigella sonnei and Shigella flexneri infections

Objectives

We aimed to quantify the impact of fluoroquinolone resistance on the clinical outcome of paediatric shigellosis patients treated with fluoroquinolones in southern Vietnam. Such information is important to inform therapeutic management for infections caused by this increasingly drug-resistant pathogen, responsible for high morbidity and mortality in young children globally.

Methods

Clinical information and bacterial isolates were derived from a randomized controlled trial comparing gatifloxacin with ciprofloxacin for the treatment of paediatric shigellosis. Time–kill experiments were performed to evaluate the impact of MIC on the in vitro growth of Shigella and Cox regression modelling was used to compare clinical outcome between treatments and Shigella species.

Results

Shigella flexneri patients treated with gatifloxacin had significantly worse outcomes than those treated with ciprofloxacin. However, the MICs of fluoroquinolones were not significantly associated with poorer outcome. The presence of S83L and A87T mutations in the gyrA gene significantly increased MICs of fluoroquinolones. Finally, elevated MICs and the presence of the qnrS gene allowed Shigella to replicate efficiently in vitro in high concentrations of ciprofloxacin.

Conclusions

We found that below the CLSI breakpoint, there was no association between MIC and clinical outcome in paediatric shigellosis infections. However, S. flexneri patients had worse clinical outcomes when treated with gatifloxacin in this study regardless of MIC. Additionally, Shigella harbouring the qnrS gene are able to replicate efficiently in high concentrations of ciprofloxacin and we hypothesize that such strains possess a competitive advantage against fluoroquinolone-susceptible strains due to enhanced shedding and transmission.

Nontherapeutic Use of Antimicrobial Agents in Animal Agriculture: Implications for Pediatrics

Antimicrobial resistance is one of the most serious threats to public health globally and threatens our ability to treat infectious diseases. Antimicrobial-resistant infections are associated with increased morbidity, mortality, and health care costs. Infants and children are affected by transmission of susceptible and resistant food zoonotic pathogens through the food supply, direct contact with animals, and environmental pathways. The overuse and misuse of antimicrobial agents in veterinary and human medicine is, in large part, responsible for the emergence of antibiotic resistance. Approximately 80% of the overall tonnage of antimicrobial agents sold in the United States in 2012 was for animal use, and approximately 60% of those agents are considered important for human medicine. Most of the use involves the addition of low doses of antimicrobial agents to the feed of healthy animals over prolonged periods to promote growth and increase feed efficiency or at a range of doses to prevent disease. These nontherapeutic uses contribute to resistance and create new health dangers for humans. This report describes how antimicrobial agents are used in animal agriculture, reviews the mechanisms of how such use contributes to development of resistance, and discusses US and global initiatives to curb the use of antimicrobial agents in agriculture.

Nonmedical Uses of Antibiotics: Time to Restrict Their Use?

The global crisis of antibiotic resistance has reached a point where, if action is not taken, human medicine will enter a postantibiotic world and simple injuries could once again be life threatening. New antibiotics are needed urgently, but better use of existing agents is just as important. More appropriate use of antibiotics in medicine is vital, but the extensive use of antibiotics outside medical settings is often overlooked. Antibiotics are commonly used in animal husbandry, bee-keeping, fish farming and other forms of aquaculture, ethanol production, horticulture, antifouling paints, food preservation, and domestically. This provides multiple opportunities for the selection and spread of antibiotic-resistant bacteria. Given the current crisis, it is vital that the nonmedical use of antibiotics is critically examined and that any nonessential use halted.