Control of fluoroquinolone resistance through successful regulation, Australia

Microwave-assisted preparation of yellow fluorescent graphitic carbon nitride quantum dots for trace tetracycline-specific detection

Tetracycline (TC) is extensively utilized in livestock breeding, aquaculture, and medical industry. TC residues seriously harm food security, the environment, and human health. There is an urgent need to exploit a highly efficient and sensitive testing method to monitor TC residue levels in aquatic environments. In this study, graphitic carbon nitride quantum dots (g-CNQDs) were successfully synthesized by a one-step microwave-assisted method using citric acid and urea as precursors. The as-prepared g-CNQDs with size of 1.25-3.75 nm exhibited bright yellow fluorescence at 523 nm when excited at 397 nm. Interestingly, this characteristic fluorescence emission of g-CNQDs could be selectively and efficiently quenched by TC. Based on this phenomenon, for TC detection was successfully explored and applied in real water samples. Wide linear scope of 7-100 μM, low detection limit (LOD) of 0.48 μM, satisfactory recovery of 97.77%-103.4%, and good relative standard deviation (RSD) of 1.05-5.87% were obtained. Mechanism investigations revealed that the static quenching and the inner filter effect (IFE) were responsible for this fluorescence quenching between g-CNQDs and TC. This work not only provided a facile approach for g-CNQDs synthesis but also constructed a g-CNQDs-based fluorescent sensor platform for the highly sensitive and selective detection of TC in aquatic environments.

The two faces of antibiotics: an overview of the effects of antibiotic residues in foodstuffs

Antibiotics, which have been used for many years to treat infections, also play an important role in food contamination with antibiotic residues. There is also unnecessary use of antibiotics, particularly to increase production efficiency. Non-compliance with withdrawal periods and maximum residue limits (MRLs) for antibiotics used in food-producing animals results in undesirable events, such as allergic reactions, teratogenicity, carcinogenicity, changes in the microbiota and, in particular, antibiotic resistance. Therefore, it may be useful to avoid unnecessary use of antibiotics, to limit the use of antibiotics and to turn to alternatives that can be used instead of antibiotics. The aim of this review is to provide information on the undesirable effects of antibiotic residues in food-producing organisms and in the environment, their determination, and the precautions that can be taken.

Genomic and clinical characteristics of campylobacteriosis in Australia

Campylobacter spp. are a common cause of bacterial gastroenteritis in Australia, primarily acquired from contaminated meat. We investigated the relationship between genomic virulence characteristics and the severity of campylobacteriosis, hospitalisation, and other host factors.We recruited 571 campylobacteriosis cases from three Australian states and territories (2018-2019). We collected demographic, health status, risk factors, and self-reported disease data. We whole genome sequenced 422 C. jejuni and 84 C. coli case isolates along with 616 retail meat isolates. We classified case illness severity using a modified Vesikari scoring system, performed phylogenomic analysis, and explored risk factors for hospitalisation and illness severity.On average, cases experienced a 7.5 day diarrhoeal illness with additional symptoms including stomach cramps (87.1 %), fever (75.6 %), and nausea (72.0 %). Cases aged ≥75 years had milder symptoms, lower Vesikari scores, and higher odds of hospitalisation compared to younger cases. Chronic gastrointestinal illnesses also increased odds of hospitalisation. We observed significant diversity among isolates, with 65 C. jejuni and 21 C. coli sequence types. Antimicrobial resistance genes were detected in 20.4 % of isolates, but multidrug resistance was rare (0.04 %). Key virulence genes such as cdtABC (C. jejuni) and cadF were prevalent (>90 % presence) but did not correlate with disease severity or hospitalisation. However, certain genes (e.g. fliK, Cj1136, and Cj1138) appeared to distinguish human C. jejuni cases from food source isolates.Campylobacteriosis generally presents similarly across cases, though some are more severe. Genotypic virulence factors identified in the literature to-date do not predict disease severity but may differentiate human C. jejuni cases from food source isolates. Host factors like age and comorbidities have a greater influence on health outcomes than virulence factors.

Assessment of Enrofloxacin Usage and Residue Levels of Enrofloxacin-Ciprofloxacin in Breast and Liver Tissues of Commercial Broilers Sold in Kampala-Uganda

Background

Human exposure to veterinary drugs like fluoroquinolones occurs due to the presence of their residues in foods from animal sources in varying concentrations. The existence of antibiotic residues in foodstuffs can pose great public health problems to consumers. This study aimed to assess enrofloxacin use patterns and assess residue levels of enrofloxacin/ciprofloxacin in breast muscle and liver tissues of broiler chickens sold for consumption in Kampala capital city.

Methods

This was a cross-sectional study that involved both field survey and laboratory-based methods. The field study involved the use of qualitative and semi-quantitative data collection tools to interview 34 broiler farmers and 10 veterinary drugs vendors. For the determination of enrofloxacin/ciprofloxacin levels, 68 chicken breast and liver tissue samples were collected from main markets in Kampala over one month and analyzed using HPLC-UV.

Results

Enrofloxacin was the most used antibiotic (100%) for the management of poultry diseases, majorly respiratory diseases (100%), salmonella infections (40%), and disease prevention (60%). Over 76% of the farmers knew the meat withdrawal time (WDT) for enrofloxacin, but none of them adhered to this. Over 70% of the farmers reported that the veterinary drugs vendors were not providing meat WDT information. Enrofloxacin/ciprofloxacin residues were identified in 35.3% (12/34) of the muscle and 38.2% (13/34) of the liver tissues analyzed. Of those muscle and liver tissue samples that tested positive, 25% (3/12) and 38.5% (5/13) respectively had drug concentrations higher than the recommended Maximum Residue Limits. The overall mean enrofloxacin/ciprofloxacin concentration in the chicken muscle and liver tissues was 83.6 (±34.5) µg/kg and 171.5 (±75.9) µg/kg.

Conclusion

This observed presence of enrofloxacin/ciprofloxacin levels above safety requirements is attributable to inadequate medicines use information provided by veterinary drugs vendors to farmers and also to the non-compliance of some farmers to meat WDT due to the economic implications.

Refractory Helicobacter pylori infection in Australia: updated multicentre antimicrobial resistance

BACKGROUND AND AIM

Helicobacter pylori infection is responsible for considerable morbidity and mortality worldwide and eradication rates are falling globally because of increasing antimicrobial resistance. However, there is a paucity of local data to guide the choice of eradication therapy in Australia. This study aimed to evaluate current Australian rates of H. pylori antibiotic resistance in patients who had failed prior eradication therapy.

METHODS

A retrospective analysis of routine culture and antibiotic susceptibility data from two pathology laboratories servicing multiple tertiary referral hospitals in Western Australia (WA) and South Australia (SA), between 2018 and 2022, was performed. Rates of antimicrobial resistance and prevalence of multiresistant isolates in both SA and WA were calculated and comparison of temporal trends and differences between the two states was conducted.

RESULTS

A total of 796 H. pylori isolates revealed a clarithromycin resistance rate of 82%, metronidazole 68%, amoxicillin 4.4% and tetracycline 0.5%. Resistance to levofloxacin was observed in 22% and rifampicin 14%. Rates of resistance to clarithromycin were lower in SA compared with WA (incidence rate ratio [IRR]: 0.69, P = 0.0001). Multiresistant isolates were discovered in 63% of patients, with lower rates in SA compared with WA (IRR: 0.74, P = 0.002).

CONCLUSION

This first multicentre, multistate study of H. pylori resistance in Australian patients exposed to prior therapy demonstrated high rates of antimicrobial resistance, including levofloxacin (>20%). This raises concern about recommending levofloxacin in empirical second-line therapies. Increased monitoring and awareness of current H. pylori resistance rates in Australia are needed to guide local eradication practices.

Assessing the mechanisms of multi-drug resistant non-typhoidal Salmonella (NTS) serovars isolated from layer chicken farms in Nigeria

BACKGROUND

In Nigeria, there have been reports of widespread multiple antimicrobial resistance (AMR) amongst Salmonella isolated from poultry. To mitigate the impact of mortality associated with Salmonella on their farms, farmers resort to the use of antimicrobials without sound diagnostic advice. We conducted this study to describe the AMR patterns, mechanisms and genetic similarities within some Salmonella serovars isolated from different layer farms.

METHOD

We determine the AMR profiles of two hundred Salmonella isolates, selected based on frequency, serovar, and geographical and sample type distribution. We also assessed the mechanisms of multi-drug resistance for specific genetic determinants by using PCR protocols and gene sequence analysis. Pulsed-field gel electrophoresis (PFGE) was conducted on seven selected serovars to determine their genetic relatedness.

RESULTS

Of 200 isolates, 97 (48.5%) revealed various AMR profiles, with the multiple antibiotic resistance (MAR) index ranging from 0.07-0.5. Resistance to ciprofloxacin was common in all the multi-drug resistant isolates, while all the isolates were susceptible to cefotaxime, ceftazidime, and meropenem. Genotypic characterization showed the presence of resistance genes as well as mutations in the nucleotide genes with subsequent amino acid substitutions. Fifteen isolates (43%) of S. Kentucky were indistinguishable, but were isolated from four different states in Nigeria (Ogun, n = 9; Kaduna, n = 6; Plateau, n = 3, and: Bauchi, n = 2). PFGE revealed 40 pulsotype patterns (Kentucky, n = 12; Larochelle, n = 9; Virchow, n = 5; Saintpaul, n = 4; Poona, n = 3; Isangi, n = 2, and; Nigeria, n = 2).

CONCLUSION

This study recorded strictly related but diversely distributed Salmonella serovars with high AMR rates in poultry. We recommend strict regulation on antimicrobial use and regular monitoring of AMR trends among bacteria isolated from animals and humans to inform public policy.

The Silent Threat: Antimicrobial-Resistant Pathogens in Food-Producing Animals and Their Impact on Public Health

The emergence of antimicrobial resistance (AMR) is a global health problem without geographic boundaries. This increases the risk of complications and, thus, makes it harder to treat infections, which can result in higher healthcare costs and a greater number of deaths. Antimicrobials are often used to treat infections from pathogens in food-producing animals, making them a potential source of AMR. Overuse and misuse of these drugs in animal agriculture can lead to the development of AMR bacteria, which can then be transmitted to humans through contaminated food or direct contact. It is therefore essential to take multifaceted, comprehensive, and integrated measures, following the One Health approach. To address this issue, many countries have implemented regulations to limit antimicrobial use. To our knowledge, there are previous studies based on AMR in food-producing animals; however, this paper adds novelty related to the AMR pathogens in livestock, as we include the recent publications of this field worldwide. In this work, we aim to describe the most critical and high-risk AMR pathogens among food-producing animals, as a worldwide health problem. We also focus on the dissemination of AMR genes in livestock, as well as its consequences in animals and humans, and future strategies to tackle this threat.

A national study confirms that Escherichia coli from Australian commercial layer hens remain susceptible to critically important antimicrobials

Controlling the use of the most critically important antimicrobials (CIAs) in food animals has been identified as one of the key measures required to curb the transmission of antimicrobial resistant bacteria from animals to humans. Expanding the evidence demonstrating the effectiveness of restricting CIA usage for preventing the emergence of resistance to key drugs amongst commensal organisms in animal production would do much to strengthen international efforts to control antimicrobial resistance (AMR). As Australia has strict controls on antimicrobial use in layer hens, and internationally comparatively low levels of poultry disease due to strict national biosecurity measures, we investigated whether these circumstances have resulted in curtailing development of critical forms of AMR. The work comprised a cross-sectional national survey of 62 commercial layer farms with each assessed for AMR in Escherichia coli isolates recovered from faeces. Minimum inhibitory concentration analysis using a panel of 13 antimicrobials was performed on 296 isolates, with those exhibiting phenotypic resistance to fluoroquinolones (a CIA) or multi-class drug resistance (MCR) subjected to whole genome sequencing. Overall, 53.0% of isolates were susceptible to all antimicrobials tested, and all isolates were susceptible to cefoxitin, ceftiofur, ceftriaxone, chloramphenicol and colistin. Resistance was observed for amoxicillin-clavulanate (9.1%), ampicillin (16.2%), ciprofloxacin (2.7%), florfenicol (2.4%), gentamicin (1.0%), streptomycin (4.7%), tetracycline (37.8%) and trimethoprim/sulfamethoxazole (9.5%). MCR was observed in 21 isolates (7.0%), with two isolates exhibiting resistance to four antimicrobial classes. Whole genome sequencing revealed that ciprofloxacin-resistant (fluoroquinolone) isolates were devoid of both known chromosomal mutations in the quinolone resistance determinant regions and plasmid-mediated quinolone resistance genes (qnr)-other than in one isolate (ST155) which carried the qnrS gene. Two MCR E. coli isolates with ciprofloxacin-resistance were found to be carrying known resistance genes including aadA1, dfrA1, strA, strB, sul1, sul2, tet(A), blaTEM-1B, qnrS1 and tet(A). Overall, this study found that E. coli from layer hens in Australia have low rates of AMR, likely due to strict control on antimicrobial usage achieved by the sum of regulation and voluntary measures.

Development of antisense peptide-peptide nucleic acids against fluoroquinolone-resistant Escherichia coli

BACKGROUND

Fluoroquinolones (FQs) are potent and broad-spectrum antibiotics commonly used to treat MDR bacterial infections, but bacterial resistance to FQs has emerged and spread rapidly around the world. The mechanisms for FQ resistance have been revealed, including one or more mutations in FQ target genes such as DNA gyrase (gyrA) and topoisomerase IV (parC). Because therapeutic treatments for FQ-resistant bacterial infections are limited, it is necessary to develop novel antibiotic alternatives to minimize or inhibit FQ-resistant bacteria.

OBJECTIVES

To examine the bactericidal effect of antisense peptide-peptide nucleic acids (P-PNAs) that can block the expression of DNA gyrase or topoisomerase IV in FQ-resistant Escherichia coli (FRE).

METHODS

A set of antisense P-PNA conjugates with a bacterial penetration peptide were designed to inhibit the expression of gyrA and parC and were evaluated for their antibacterial activities.

RESULTS

Antisense P-PNAs, ASP-gyrA1 and ASP-parC1, targeting the translational initiation sites of their respective target genes significantly inhibited the growth of the FRE isolates. In addition, ASP-gyrA3 and ASP-parC2, which bind to the FRE-specific coding sequence within the gyrA and parC structural genes, respectively, showed selective bactericidal effects against FRE isolates.

CONCLUSIONS

Our results demonstrate the potential of targeted antisense P-PNAs as antibiotic alternatives against FQ-resistance bacteria.

Antibiotic Resistance among Gastrointestinal Bacteria in Broilers: A Review Focused on Enterococcus spp. and Escherichia coli

Chickens can acquire bacteria at different stages, and bacterial diversity can occur due to production practices, diet, and environment. The changes in consumer trends have led to increased animal production, and chicken meat is one of the most consumed meats. To ensure high levels of production, antimicrobials have been used in livestock for therapeutic purposes, disease prevention, and growth promotion, contributing to the development of antimicrobial resistance across the resident microbiota. Enterococcus spp. and Escherichia coli are normal inhabitants of the gastrointestinal microbiota of chickens that can develop strains capable of causing a wide range of diseases, i.e., opportunistic pathogens. Enterococcus spp. isolated from broilers have shown resistance to at least seven classes of antibiotics, while E. coli have shown resistance to at least four. Furthermore, some clonal lineages, such as ST16, ST194, and ST195 in Enterococcus spp. and ST117 in E. coli, have been identified in humans and animals. These data suggest that consuming contaminated animal-source food, direct contact with animals, or environmental exposure can lead to the transmission of antimicrobial-resistant bacteria. Therefore, this review focused on Enterococcus spp. and E. coli from the broiler industry to better understand how antibiotic-resistant strains have emerged, which antibiotic-resistant genes are most common, what clonal lineages are shared between broilers and humans, and their impact through a One Health perspective.

Justifying the More Restrictive Alternative: Ethical Justifications for One Health AMR Policies Rely on Empirical Evidence

Global consumption of antibiotics has accelerated the evolution of bacterial antimicrobial resistance. Yet, the risks from increasing bacterial antimicrobial resistance are not restricted to human populations: transmission of antimicrobial resistant bacteria occurs between humans, farms, the environment and other reservoirs. Policies that take a 'One Health' approach deal with this cross-reservoir spread, but are often more restrictive concerning human actions than policies that focus on a single reservoir. As such, the burden of justification lies with these more restrictive policies. We argue that an ethical justification for preferring One Health policies over less restrictive alternatives relies on empirical evidence as well as theory. The ethical justification for these policies is based on two arguments: (i) comparatively greater effectiveness, and (ii) comparatively better tracking of moral responsibility. Yet the empirical assumptions on which these claims rest are limited by existing empirical knowledge. Using livestock farming as an example, we suggest that scientific research into characterising antimicrobial resistance and linking practices to outcomes ought to be guided (at least in part) by the imperative to supply the context-specific data needed to ethically justify preferring a One Health policy over less restrictive alternatives.

Swine Colibacillosis: Global Epidemiologic and Antimicrobial Scenario

Swine pathogenic infection caused by Escherichia coli, known as swine colibacillosis, represents an epidemiological challenge not only for animal husbandry but also for health authorities. To note, virulent E. coli strains might be transmitted, and also cause disease, in humans. In the last decades, diverse successful multidrug-resistant strains have been detected, mainly due to the growing selective pressure of antibiotic use, in which animal practices have played a relevant role. In fact, according to the different features and particular virulence factor combination, there are four different pathotypes of E. coli that can cause illness in swine: enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC) that comprises edema disease E. coli (EDEC) and enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), and extraintestinal pathogenic E. coli (ExPEC). Nevertheless, the most relevant pathotype in a colibacillosis scenario is ETEC, responsible for neonatal and postweaning diarrhea (PWD), in which some ETEC strains present enhanced fitness and pathogenicity. To explore the distribution of pathogenic ETEC in swine farms and their diversity, resistance, and virulence profiles, this review summarizes the most relevant works on these subjects over the past 10 years and discusses the importance of these bacteria as zoonotic agents.

Comparison of Antimicrobial Resistance among Commensal Escherichia coli Isolated from Retail Table Eggs Produced by Laying Hens from the Cage and Non-Cage Housing Systems in Western Australia

Antimicrobial resistance (AMR) has become a global public health concern in recent decades. Although several investigations evaluated AMR in commensal and pathogenic bacteria from different foods of animal origin in Australia, there is a lack of studies that compared AMR in commensal E. coli isolated from retail table eggs obtained from different laying hen housing systems. This study aimed to determine AMR and differences in AMR patterns among E. coli isolates recovered from retail table eggs sourced from caged and non-caged housing systems in Western Australia. Commensal E. coli isolates were tested for susceptibility to 14 antimicrobials using a broth microdilution method. Clustering analyses and logistic regression models were applied to identify patterns and differences in AMR. Overall, there were moderate to high frequencies of resistance to the antimicrobials of lower importance used in Australian human medicine (tetracycline, ampicillin, trimethoprim, and sulfamethoxazole) in the isolates sourced from the eggs of two production systems. All E. coli isolates were susceptible to all critically important antimicrobials except the very low level of resistance to ciprofloxacin. E. coli isolates from eggs of non-caged systems had higher odds of resistance to tetracycline (OR = 5.76, p < 0.001) and ampicillin (OR = 3.42, p ≤ 0.01) compared to the isolates from eggs of caged systems. Moreover, the number of antimicrobials to which an E. coli isolate was resistant was significantly higher in table eggs from non-caged systems than isolates from caged systems’ eggs. Considering the conservative approach in using antimicrobials in the Australian layer flocks, our findings highlight the potential role of the environment or human-related factors in the dissemination and emergence of AMR in commensal E. coli, particularly in retail table eggs of non-cage system origin. Further comprehensive epidemiological studies are required to better understand the role of different egg production systems in the emergence and dissemination of AMR in commensal E. coli.

Epidemiology and Economic Cost Analysis of Microbial Keratitis from a Tertiary Referral Hospital in Australia

Microbial keratitis is the most common cause of infective vision loss. The causative organism varies by region, and most cases require intensive antimicrobial therapy. The purpose of this study was to analyse the causative organisms of microbial keratitis, its presentation and economic burden from a tertiary referral hospital in Australia. A retrospective review of 160 cases of microbial keratitis was performed, over a 5-year period from 2015–2020. A wide variety of costs were considered to determine the economic burden, using standardized data from the Independent Hospital Pricing Authority and the cost of personal income loss. Our study showed the most commonly occurring pathogens were Herpes Simplex (16%), Staphylococcus aureus (15.1%) and Pseudomonas aeruginosa (14.3%). A total of 59.3% of patients were admitted, with a median length of admission of 7 days. Median cost for all presentations of microbial keratitis was AUD 8013 (USD 5447), with costs significantly increasing with admission. The total annual cost of microbial keratitis within Australia is estimated to be AUD 13.58 million (USD 9.23 million). Our findings demonstrate that microbial keratitis represents a significant economic burden for eye-related diseases and the key driving factor for the cost is the length of admission. Minimizing the duration of admission, or opting for outpatient management where appropriate, would significantly reduce the cost of treatment for microbial keratitis.

Overview of Side-Effects of Antibacterial Fluoroquinolones: New Drugs versus Old Drugs, a Step Forward in the Safety Profile?

Antibacterial fluoroquinolones (FQs) are frequently used in treating infections. However, the value of FQs is debatable due to their association with severe adverse effects (AEs). The Food and Drug Administration (FDA) issued safety warnings concerning their side-effects in 2008, followed by the European Medicine Agency (EMA) and regulatory authorities from other countries. Severe AEs associated with some FQs have been reported, leading to their withdrawal from the market. New systemic FQs have been recently approved. The FDA and EMA approved delafloxacin. Additionally, lascufloxacin, levonadifloxacin, nemonoxacin, sitafloxacin, and zabofloxacin were approved in their origin countries. The relevant AEs of FQs and their mechanisms of occurrence have been approached. New systemic FQs present potent antibacterial activity against many resistant bacteria (including resistance to FQs). Generally, in clinical studies, the new FQs were well-tolerated with mild or moderate AEs. All the new FQs approved in the origin countries require more clinical studies to meet FDA or EMA requirements. Post-marketing surveillance will confirm or infirm the known safety profile of these new antibacterial drugs. The main AEs of the FQs class were addressed, highlighting the existing data for the recently approved ones. In addition, the general management of AEs when they occur and the rational use and caution of modern FQs were outlined.

Antibiotic treatment durations for common infectious diseases in Switzerland: comparison between real-life and local and international guideline recommendations

OBJECTIVES

Shortening the duration of antibiotic therapy (DAT) for common infectious diseases may be an effective strategy to tackle antimicrobial resistance. Shorter DAT has been proven safe and effective for community-acquired pneumonia (CAP), cellulitis, and cholangitis.

METHODS

In a retrospective multicentre quality-control study, medical records of 770 patients hospitalized with CAP, cellulitis, and cholangitis at three tertiary care hospitals in Switzerland during 2017-2018 were randomly selected. Appropriateness of antibiotic treatment duration was assessed according to international and local guidelines.

RESULTS

Records of 271, 260, and 239 patients with CAP, cellulitis, and cholangitis were included, respectively. Median DAT was seven days (interquartile range [IQR] 6-9), ten days (IQR 8-13), and nine days (IQR 6-13) in CAP, cellulitis, and cholangitis, respectively. DAT longer than recommended by local and international guidelines was observed in 32% and 37% of CAP patients, 23% and 70% of cellulitis patients, and 33% and 37% of cholangitis patients, respectively. Positive blood cultures (odds ratio [OR] = 2.42 (95% confidence interval [CI] 1.33-4.34]), infectious diseases consultation (OR = 1.79 [95% CI 1.05-2.78]), impaired renal function (OR = 0.99 [95% CI 0.98-1.00] per 1 ml/min / 1.73 m² increase in estimated glomerular filtration rate) and a higher degree of inflammation on admission (OR = 1.0 [95% CI 1.001-1.005] per 10 mg/L increase in C-reactive protein) were independently associated with a DAT longer than recommended in international guidelines.

CONCLUSIONS

DAT exceeded recommendations in a significant proportion of patients with mostly community-acquired infections.

[Antibiotic resistance - what can be done? A review]

Serious work is being carried out in the world in the field of combating antibiotic resistance: reducing the prescribing of antibiotics, banning the use of antibiotics as stimulators of animal growth, improving infection control. Antimicrobial resistance is systematically monitored not only in every medical center, but also at the national level. The collected data is successfully used to implement local and national recommendations on the optimal use of antibiotics.

The Mechanisms Involved in the Fluoroquinolone Resistance of Salmonella enterica Strains Isolated from Humans in Poland, 2018-2019: The Prediction of Antimicrobial Genes by In Silico Whole-Genome Sequencing

Salmonellosis remains the second most common zoonosis in Europe. Resistance to fluoroquinolones (FQs) in Salmonella has been increasing worldwide, with WHO considering FQ-resistant Salmonella spp. as high-priority pathogens. The aim of this study was a retrospective analysis of the molecular mechanisms of FQ resistance, detected among clinical ciprofloxacin-resistant Salmonella enterica belonging to the most common serotypes. The whole genome sequences (WGS) of tested isolates were also analysed for the occurrence of other antimicrobial resistance determinants. Out of a total of 1051 Salmonella collected in the years 2018-2019, 447 strains belonging to the most common serotypes in Poland were selected were screened for FQ resistance using the pefloxacin disc test according to EUCAST recommendations. All pefloxacin-resistant isolates were confirmed as ciprofloxacin-resistant using the E-test. A total of 168 (37.6%) Salmonella enterica, which belonged to seven serotypes, were resistant to ciprofloxacin (mostly Hadar, Virchow and Newport). A hundred randomly selected Salmonella were investigated by WGS. A total of 127 QRDR mutations in GyrA and ParC were identified in 93 isolates. The qnr genes were the only PMQR determinants detected and were found in 19% of the sequenced isolates. Moreover, 19 additional resistance genes (including: bla,_,tet, sul, aad, aac-, ant-, aph-, floR, cmlA) were identified among the FQ-resistant Salmonella tested that confer resistance to clinically important antibiotics such as β-lactams, tetracyclines, sulphonamides, aminoglycosides and phenicol, respectively). In conclusion, FQ resistance of human Salmonella in Poland is rising towards a critical level and needs to be tightly monitored.

Growth kinetics and fitness of fluoroquinolone resistant and susceptible Campylobacter jejuni strains of cattle origin

Human enterocolitis is frequently caused by the Gram-negative microaerobic bacterium Campylobacter jejuni. Macrolides (e.g., erythromycin) and fluoroquinolones (FQs) (e.g., ciprofloxacin) are the preferred antibiotics for the treatment of human campylobacteriosis. Rapid emergence of FQ-resistant (FQ-R) Campylobacter during treatment with FQ antimicrobials is well known to occur in poultry. Cattle is also an important reservoir of Campylobacter for humans, and FQ-R Campylobacter from cattle has become highly prevalent in recent years. Even though the selection pressure may have contributed to the expansion of FQ-R Campylobacter, the actual impact of this factor appears to be rather low. In this study, we examined the hypothesis that the fitness of FQ-R Campylobacter may have also played a role in the rise seen in FQ-R Campylobacter isolates by employing a series of in vitro experiments in MH broth and bovine fecal extract. First, it was shown that FQ-R and FQ-susceptible (FQ-S) C. jejuni strains of cattle origin had comparable growth rates when individually cultured in both MH broth and the fecal extract with no antibiotic present. Interestingly, FQ-R strains had small but statistically significant increases over FQ-S strains in growth in competition experiments performed in mixed cultures with no antibiotic present. Lastly, it was observed that FQ-S C. jejuni strains developed resistance to ciprofloxacin more readily at high initial bacterial cell density (10⁷ CFU/mL) and when exposed to low levels of the antibiotic (2-4 μg/mL) compared with that at a low level of initial bacterial cell density (10⁵ CFU/mL) and exposure to a high level of ciprofloxacin (20 μg/mL) in both MH broth and the fecal extract. Altogether, these findings indicate that even though FQ-R C. jejuni of cattle origin may have a slightly higher fitness advantage over the FQ-S population, the emergence of FQ-R mutants from susceptible strains is primarily dictated by the bacterial cell density and the antibiotic concentration exposed under in vitro condition. These observation may also provide plausible explanations for the high prevalence of FQ-R C. jejuni in cattle production due to its overall fit nature in the absence of antibiotic selection pressure and for the paucity of development of FQ-R C. jejuni in the cattle intestine in response to FQ-treatment, as observed in our recent studies.

Current and Emerging Treatment Options for Multidrug Resistant Escherichia coli Urosepsis: A Review

Escherichia coli is a versatile commensal and pathogenic member of the human microflora. As the primary causative pathogen in urosepsis, E. coli places an immense burden on healthcare systems worldwide. To further exacerbate the issue, multi drug resistance (MDR) has spread rapidly through E. coli populations, making infections more troublesome and costlier to treat. This paper aimed to review the literature concerning the development of MDR in uropathogenic E. coli (UPEC) and explore the existing evidence of current and emerging treatment strategies. While some MDR strains maybe treated with β-lactam-β-lactamase inhibitor combinations as well as cephalosporins, cephamycin, temocillin and fosfomycin, current treatment strategies for many MDR UPEC strains are reliant on carbapenems. Carbapenem overreliance may contribute to the alarming dissemination of carbapenem-resistance amongst some UPEC communities, which has ushered in a new age of difficult to treat infections. Alternative treatment options for carbapenem resistant UPEC may include novel β-lactam-β-lactamase or carbapenemase inhibitor combinations, cefiderocol, polymyxins, tigecycline, aminoglycosides or fosfomycin. For metallo-β-lactamase producing strains (e.g., NDM, IMP-4), combinations of cefazidime-avibacam with aztreonam have been used. Additionally, the emergence of new antimicrobials brings new hope to the treatment of such infections. However, continued research is required to successfully bring these into the clinic for the treatment of MDR E. coli urosepsis.

Governing Antibiotic Risks in Australian Agriculture: Sustaining Conflicting Common Goods Through Competing Compliance Mechanisms

The One Health approach to antimicrobial resistance (AMR) requires stakeholders to contribute to cross-sectoral efforts to improve antimicrobial stewardship (AMS). One Health AMR policy implementation is challenging in livestock farming because of the infrastructural role of antibiotics in production systems. Mitigating AMR may require the development of more stringent stewardship obligations and the future limitation of established entitlements. Drawing on Amatai Etzioni’s compliance theory, regulatory analyses and qualitative studies with stakeholder groups we examine the structural and socio-cultural dimension of antibiotic use and AMS compliance in Australian beef and dairy production. We found a disconnect between how antibiotic use is conceptualised by farmers and the way in which AMS policies construe agricultural AMR risks. Under the umbrella of food safety standards and national-level prescribing restrictions, farmers and veterinarians interact around antibiotic use with different operating logics and compliance mechanisms. These parallel regimes service distinct and sometimes competing common goods of food security and antibiotic preservation. Further reforms to mitigate AMR need to account for the value orientations of different groups and the embeddedness of the constraints imposed by existing systems. Advocacy for greater AMR precaution in agriculture should acknowledge and compensate for erosions in competing common goods and the cost of proposed interventions.

Attitudes towards Use of High-Importance Antimicrobials—A Cross-Sectional Study of Australian Veterinarians

The timely implementation of antimicrobial stewardship interventions could delay or prevent the development of higher levels of antimicrobial resistance in the future. In food-producing animals in Australia, high-importance antimicrobials, as rated by the Australian Strategic and Technical Advisory Group (ASTAG), include virginiamycin and third-generation cephalosporins (in individual pigs or cattle). The use of high-importance antimicrobials in companion animals is more widespread and less regulated. There is no national antimicrobial use surveillance system for animals in Australia. Consequently, there is a gap in the knowledge about reasonable use across all sectors of veterinary practice. This study explored attitudes towards the use in veterinary medicine of antimicrobials with high importance to human health, and determined levels of agreement about the introduction of restrictions or other conditions on this use. An online survey was distributed via social media and email from June to December 2020 to veterinarians working in Australia. Of the 278 respondents working in clinical practice, 49% had heard of the ASTAG rating system, and 22% used a traffic light system for antimicrobial importance in their practice. Overall, 61% of participants disagreed that veterinarians should be able to prescribe high-importance antimicrobials without restrictions. If there were to be restrictions, there was most agreement amongst all respondents for only restricting high-importance antimicrobials (73%). There is a need for education, guidance, and practical support for veterinarians for prescribing high-importance antimicrobials alongside any restrictions.

Sodium Dodecyl Sulfate-Mediated Graphene Sensor for Electrochemical Detection of the Antibiotic Drug: Ciprofloxacin

The present study involves detecting and determining CIP by a new electrochemical sensor based on graphene (Gr) in the presence of sodium dodecyl sulfate (SDS) employing voltammetric techniques. Surface morphology studies of the sensing material were analyzed using a scanning electron microscope (SEM) and atomic force microscope (AFM). In the electroanalysis of CIP at the developed electrode, an enhanced anodic peak response was recorded, suggesting the electro-oxidation of CIP at the electrode surface. Furthermore, we evaluated the impact of the electrolytic solution, scan rate, accumulation time, and concentration variation on the electrochemical behavior of CIP. The possible electrode mechanism was proposed based on the acquired experimental information. A concentration variation study was performed using differential pulse voltammetry (DPV) in the lower concentration range, and the fabricated electrode achieved a detection limit of 2.9 × 10^-8 M. The proposed sensor detected CIP in pharmaceutical and biological samples. The findings displayed good recovery, with 93.8% for tablet analysis and 93.3% to 98.7% for urine analysis. The stability of a developed electrode was tested by inter- and intraday analysis.

E. coli bacteraemia and antimicrobial resistance following antimicrobial prescribing for urinary tract infection in the community

Background

Urinary tract infections are one of the most common infections in primary and secondary care, with the majority of antimicrobial therapy initiated empirically before culture results are available. In some cases, however, over 40% of the bacteria that cause UTIs are resistant to some of the antimicrobials used, yet we do not know how the patient outcome is affected in terms of relapse, treatment failure, progression to more serious illness (bacteraemia) requiring hospitalization, and ultimately death. This study analyzed the current patterns of antimicrobial use for UTI in the community in Scotland, and factors for poor outcomes.

Objectives

To explore antimicrobial use for UTI in the community in Scotland, and the relationship with patient characteristics and antimicrobial resistance in E. coli bloodstream infections and subsequent mortality.

Methods

We included all adult patients in Scotland with a positive blood culture with E. coli growth, receiving at least one UTI-related antimicrobial (amoxicillin, amoxicillin/clavulanic acid, ciprofloxacin, trimethoprim, and nitrofurantoin) between 1st January 2009 and 31st December 2012. Univariate and multivariate logistic regression analysis was performed to understand the impact of age, gender, socioeconomic status, previous community antimicrobial exposure (including long-term use), prior treatment failure, and multi-morbidity, on the occurrence of E. coli bacteraemia, trimethoprim and nitrofurantoin resistance, and mortality.

Results

There were 1,093,227 patients aged 16 to 100 years old identified as receiving at least one prescription for the 5 UTI-related antimicrobials during the study period. Antimicrobial use was particularly prevalent in the female elderly population, and 10% study population was on long-term antimicrobials. The greatest predictor for trimethoprim resistance in E. coli bacteraemia was increasing age (OR 7.18, 95% CI 5.70 to 9.04 for the 65 years old and over group), followed by multi-morbidity (OR 5.42, 95% CI 4.82 to 6.09 for Charlson Index 3+). Prior antimicrobial use, along with prior treatment failure, male gender, and higher deprivation were also associated with a greater likelihood of a resistant E. coli bacteraemia. Mortality was significantly associated with both having an E. coli bloodstream infection, and those with resistant growth.

Conclusion

Increasing age, increasing co-morbidity, lower socioeconomic status, and prior community antibiotic exposure were significantly associated with a resistant E. coli bacteraemia, which leads to increased mortality.

Application of Plant-Derived Nanoparticles (PDNP) in Food-Producing Animals as a Bio-Control Agent against Antimicrobial-Resistant Pathogens

Antibiotics are regularly used in animal husbandry to treat diseases. This practice is beneficial to animals’ health and helps ensure food security. However, the misuse of antibiotics, especially in food-producing animals, has resulted in the advent of antimicrobial resistance (AMR) and its dissemination among foodborne pathogens. The occurrence of AMR in bacteria pathogens that cause infections in animals and those associated with food spoilage is now considered a global health concern affecting humans, animals and the environment. The search for alternative antimicrobial agents has kindled the interest of many researchers. Among the alternatives, using plant-derived nanoparticles (PDNPs) for treating microbial dysfunctions in food-producing animals has gained significant attention. In traditional medicine, plant extracts are considered as safe, efficient and natural antibacterial agents for various animal diseases. Given the complexity of the AMR and concerns about issues at the interface of human health, animal health and the environment, it is important to emphasize the role of a One Health approach in addressing this problem. This review examines the potential of PDNPs as bio-control agents in food-producing animals, intending to provide consumers with microbiologically safe food while ensuring food safety and security, better health for animals and humans and a safe environment.

Studying Factors Affecting Success of Antimicrobial Resistance Interventions through the Lens of Experience: A Thematic Analysis

Antimicrobial resistance (AMR) affects the environment, and animal and human health. Institutions worldwide have applied various measures, some of which have reduced antimicrobial use and AMR. However, little is known about factors influencing the success of AMR interventions. To address this gap, we engaged health professionals, designers, and implementers of AMR interventions in an exploratory study to learn about their experience and factors that challenged or facilitated interventions and the context in which interventions were implemented. Based on participant input, our thematic analysis identified behaviour; institutional governance and management; and sharing and enhancing information as key factors influencing success. Important sub-themes included: correct behaviour reinforcement, financial resources, training, assessment, and awareness of AMR. Overall, interventions were located in high-income countries, the human sector, and were publicly funded and implemented. In these contexts, behaviour patterns strongly influenced success, yet are often underrated or overlooked when designing AMR interventions. Improving our understanding of what contributes to successful interventions would allow for better designs of policies that are tailored to specific contexts. Exploratory approaches can provide encouraging results in complex challenges, as made evident in our study. Remaining challenges include more engagement in this type of study by professionals and characterisation of themes that influence intervention outcomes by context.

Characterisation of plasmids harbouring qnrA1, qnrS1, and qnrB4 in E. coli isolated in the Philippines from food-producing animals and their products

OBJECTIVES

Determinants showing plasmid-mediated quinolone resistance, which usually leads to antimicrobial ineffectiveness, have become an emerging clinical problem. In our previous study in the Philippines, a high prevalence of Qnr determinants was found in clinical samples and food-producing animals and their food products. However, no qnr-carrying plasmids have been investigated in animals or animal-derived foods. Hence, in the present, we aimed to characterise qnr-carrying plasmids in Escherichia coli isolated from the food supply chain.

METHODS

Plasmids from 44 qnr-positive isolates were assigned to incompatibility groups by PCR-based replicon typing, and the presence of β-lactamase-encoding genes were investigated by PCR. Localisation of qnr in plasmids was determined by S1-PFGE and Southern blot hybridisation. The transferability of qnr-carrying plasmids was examined by conjugation analysis.

RESULTS

Overall, 77.3% (95%CI = 62.2 - 88.5) of the isolates harbouring qnr determinants were positive for seven plasmid types, and 56.8% concurrently harboured bla_TEM-1. Plasmid IncF_repB was prevalent (65.9%, 95%CI = 50.1 - 79.5) among qnr determinants. Localisation of qnr determinants in IncF_repB and transferability of plasmids was further confirmed.

CONCLUSIONS

The current study proved that qnr in E. coli isolated from food-producing animals and their food products could spread via plasmid IncF_repB upon selective pressure with quinolones or other antimicrobials. Therefore, to curb the emergence and spread of qnr-harbouring bacteria in the Philippines, prudent use of antimicrobials in animal production and stricter hygiene and food handling are recommended.

Implications of Veterinary Medicine in the comprehension and stewardship of antimicrobial resistance phenomenon. From the origin till nowadays

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Antibiotic resistance is a well-known phenomenon with several implications

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The contribution of Veterinary Medicine is underestimated.

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It was believed that only livestock was responsible for antibiotic resistance.

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Companion animals, wild animals and environment are more involved than estimated.

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Educational tools for public and more veterinary specialists are needed.

Antimicrobial resistance (AMR) is defined by the entire scientific community as the major threat for human health and it is responsible for an increase in morbidity and mortality rates. The reasons behind this phenomenon are complex and the solution is achievable only considering the One Health approach, that encompasses the integration and implementation of human health, veterinary medicine and environmental status. Authors aimed to write this review to summarize to readers the three milestones of One-Health, underlying the most important topics in which veterinary medicine is mostly involved. Therefore, a short introduction about the history of AMR in veterinary medicine is provided, then more detailed aspects about the impact of AMR related to pets, food producing animals, wild animals and environment are discussed. Finally, some critical aspects about current and future issues are considered.

Antibiotic Resistance: One Health One World Outlook

Antibiotic resistance (ABR) is a growing public health concern worldwide, and it is now regarded as a critical One Health issue. One Health’s interconnected domains contribute to the emergence, evolution, and spread of antibiotic-resistant microorganisms on a local and global scale, which is a significant risk factor for global health. The persistence and spread of resistant microbial species, and the association of determinants at the human-animal-environment interface can alter microbial genomes, resulting in resistant superbugs in various niches. ABR is motivated by a well-established link between three domains: human, animal, and environmental health. As a result, addressing ABR through the One Health approach makes sense. Several countries have implemented national action plans based on the One Health approach to combat antibiotic-resistant microbes, following the Tripartite’s Commitment Food and Agriculture Organization (FAO)-World Organization for Animal Health (OIE)-World Health Organization (WHO) guidelines. The ABR has been identified as a global health concern, and efforts are being made to mitigate this global health threat. To summarize, global interdisciplinary and unified approaches based on One Health principles are required to limit the ABR dissemination cycle, raise awareness and education about antibiotic use, and promote policy, advocacy, and antimicrobial stewardship.

Prescribing Patterns for Upper Respiratory Tract Infections: A Prescription-Review of Primary Care Practice in Quetta, Pakistan and the Implications

Background: To identify and address the potential overuse of antibiotics, it is important to ascertain the prescribing practices of physicians. We, therefore, conducted this prescription analysis to document URTI-specific antibiotic prescription frequency in a public primary healthcare setting of Quetta city, Pakistan.

Methods: A retrospective record review was conducted of all prescriptions for URTIs in Combined Military Hospital, Quetta from 1 March to 31st May 2021. The Mann-Whitney U and Jonckheere–Terpstra test was used to evaluate the association between the tendencies of a different group of prescribers. p-value of <0.05 was of statistical significance.

Results: Over the 3 months, 50,705 prescriptions were screened and analyzed according to the established inclusion and exclusion criteria. A total of 4,126 (8.13%) URTI prescriptions met the inclusion criteria, of which 2,880 (69.80%) prescriptions contained antibiotics. Among all antibiotics, penicillins (Amoxicillin + Clavulanate) were the most prescribed antibiotic, constituting 1,323 (45.9%) of total antibiotics prescribed for all cases, followed by the Macrolide group 527 (18.2%). The Jonckheere–Terpstra test revealed a statistically significant association between the status of the prescriber and the diagnosis (p = 0.002). Furthermore, a moderate positive trend was reported with specialists being more competent in antibiotic prescribing based on their diagnosis, followed by postgraduates and house officers (τ = 0.322).

Conclusion: The prescribing patterns for the management of URTIs in the hospital were inconsistent with current guidelines. Strict adherence to guidelines must be ensured and antibiotic prescribing for URTIs should be discouraged.

Prevalence and outcomes of Clostridioides difficile infection in liver transplant recipients

BACKGROUND AND AIM

Data are limited on whether Clostridioides difficile infection (CDI) in the first year after liver transplantation (LT) is associated with increased mortality. In an Australian setting without hypervirulent strain of C. difficile we investigated the prevalence, risk factors, and patient survival associated with CDI in LT.

METHODS

Consecutive patients who underwent deceased-donor LT from 2007 to 2017 were studied retrospectively. Prevalence and long-term outcomes of LT recipients with and without CDI were examined in the entire LT cohort. A case-control study was performed to investigate risk factors associated with CDI.

RESULTS

Six hundred and forty-nine patients underwent LT, of which 32 (4.9%) were diagnosed with CDI within the first 12 months post-LT. There was no difference in patient survival in the overall LT cohort on Kaplan-Meier analysis when stratified by CDI status (log-rank test, p = .08). Furthermore, age was the only predictor of mortality on Cox regression (hazard ratio (HR) 1.06, 95% confidence interval (CI) 1.00-1.13, p = .03). On multivariable logistic regression, rifaximin pre-LT reduced risk (odds ratio (OR) 0.22, 95% CI 0.65-0.74, p = .01) whereas antibiotics pre-LT (OR 7.02, 95% CI 1.26-39.01, p = .03) and length of hospital stay after LT (OR 1.03, 95% CI 1.01-1.06, p = .02) were associated with increased risk of CDI.

CONCLUSIONS

Within the local setting of our study, CDI within 12 months post-LT is of low severity, associated with pre-LT antibiotic exposure and longer hospital stay but no survival impact after LT. Rifaximin use pre-LT reduced the risk of CDI post-LT.

Fluoroquinolone antibiotics and adverse events

Fluoroquinolones are broad-spectrum antibiotics with good oral bioavailability. They are used for the treatment of a wide variety of infections, but there are restrictions on prescribing these drugs.

Epidemiological studies have reported an increased risk of rare adverse effects. These include tendinopathy and tendon rupture, peripheral neuropathy and aortic aneurysm.

Safe prescribing of fluroquinolones requires recognition of patients with risk factors for toxicity. Prompt drug discontinuation is recommended in the event of an adverse reaction.

Practising antimicrobial stewardship by prescribing fluoroquinolones only when alternative drugs are unavailable is also key to limiting adverse events and antibiotic resistance.

Antibiotic resistance in uropathogens across northern Australia 2007-20 and impact on treatment guidelines

BACKGROUND

Urinary tract infections are common and are increasingly resistant to antibiotic therapy. Northern Australia is a sparsely populated region with limited access to healthcare, a relatively high burden of disease, a substantial regional and remote population, and high rates of antibiotic resistance in skin pathogens.

OBJECTIVES

To explore trends in antibiotic resistance for common uropathogens Escherichia coli and Klebsiella pneumoniae in northern Australia, and how these relate to current treatment guidelines in the community and hospital settings.

METHODS

We used data from an antibiotic resistance surveillance system. We calculated the monthly and yearly percentage of isolates that were resistant in each antibiotic class, by bacterium. We analysed resistance proportions geographically and temporally, stratifying by healthcare setting. Using simple linear regression, we investigated longitudinal trends in monthly resistance proportions and correlation between community and hospital isolates.

RESULTS

Our analysis included 177 223 urinary isolates from four pathology providers between 2007 and 2020. Resistance to most studied antibiotics remained <20% (for E. coli and K. pneumoniae, respectively, in 2019: amoxicillin/clavulanate 16%, 5%; cefazolin 17%, 8%; nitrofurantoin 1%, 31%; trimethoprim 36%, 17%; gentamicin 7%, 2%; extended-spectrum cephalosporins 8%, 5%), but many are increasing by 1%-3% (absolute) per year. Patterns of resistance were similar between isolates from community and hospital patients.

CONCLUSIONS

Antibiotic resistance in uropathogens is increasing in northern Australia, but treatment guidelines generally remain appropriate for empirical therapy of patients with suspected infection (except trimethoprim in some settings). Our findings demonstrate the importance of local surveillance data (HOTspots) to inform clinical decision making and guidelines.

Bacteraemia, antimicrobial susceptibility and treatment among Campylobacter-associated hospitalisations in the Australian Capital Territory: a review

BACKGROUND

Campylobacter spp. cause mostly self-limiting enterocolitis, although a significant proportion of cases require hospitalisation highlighting potential for severe disease. Among people admitted, blood culture specimens are frequently collected and antibiotic treatment is initiated. We sought to understand clinical and host factors associated with bacteraemia, antibiotic treatment and isolate non-susceptibility among Campylobacter-associated hospitalisations.

METHODS

Using linked hospital microbiology and administrative data we identified and reviewed Campylobacter-associated hospitalisations between 2004 and 2013. We calculated population-level incidence for Campylobacter bacteraemia and used logistic regression to examine factors associated with bacteraemia, antibiotic treatment and isolate non-susceptibility among Campylobacter-associated hospitalisations.

RESULTS

Among 685 Campylobacter-associated hospitalisations, we identified 25 admissions for bacteraemia, an estimated incidence of 0.71 cases per 100,000 population per year. Around half of hospitalisations (333/685) had blood culturing performed. Factors associated with bacteraemia included underlying liver disease (aOR 48.89, 95% CI 7.03-340.22, p < 0.001), Haematology unit admission (aOR 14.67, 95% CI 2.99-72.07, p = 0.001) and age 70-79 years (aOR 4.93, 95% CI 1.57-15.49). Approximately one-third (219/685) of admissions received antibiotics with treatment rates increasing significantly over time (p < 0.05). Factors associated with antibiotic treatment included Gastroenterology unit admission (aOR 3.75, 95% CI 1.95-7.20, p < 0.001), having blood cultures taken (aOR 2.76, 95% CI 1.79-4.26, p < 0.001) and age 40-49 years (aOR 2.34, 95% CI 1.14-4.79, p = 0.02). Non-susceptibility of isolates to standard antimicrobials increased significantly over time (p = 0.01) and was associated with overseas travel (aOR 11.80 95% CI 3.18-43.83, p < 0.001) and negatively associated with tachycardia (aOR 0.48, 95%CI 0.26-0.88, p = 0.02), suggesting a healthy traveller effect.

CONCLUSIONS

Campylobacter infections result in considerable hospital burden. Among those admitted to hospital, an interplay of factors involving clinical presentation, presence of underlying comorbidities, complications and increasing age influence how a case is investigated and managed.

Impact of changing reimbursement criteria on the use of fluoroquinolones in Belgium

Objectives

The criteria for the reimbursement of fluoroquinolones changed in Belgium on 1 May 2018. This study aims to quantify the difference in fluoroquinolone use after this change, and to assess the timing and persistence of this effect, both in terms of total reimbursed fluoroquinolone use and its relative proportion.

Methods

Longitudinal reimbursement data on fluoroquinolone use in the Belgian community from January 2017 to November 2018 were analysed to identify a change in reimbursed fluoroquinolone use expressed in DDD per 1000 inhabitants per day (DID), using a set of non-linear mixed models including change-points. In addition, longitudinal data on the relative proportion of prescribed fluoroquinolones from January 2017 to December 2018 were analysed to identify a change in the relative proportion of prescribed fluoroquinolones using generalized estimation equations including change-points.

Results

Fluoroquinolone use dropped significantly immediately after the change in reimbursement criteria, from 2.21 DID (95% CI: 2.03–2.38) to 0.52 DID (95% CI: 0.48–0.56) and from 9.14% (95% CI: 8.75%–9.56%) to 6.52% (95% CI: 6.04%–7.04%). The observed decrease in fluoroquinolone use persisted over time.

Conclusions

While fluoroquinolone use was still above the target of 5% after the change in reimbursement criteria, its implementation helped to lower fluoroquinolone use in Belgium.

Antibiotic use and resistance in Belgium: the impact of two decades of multi-faceted campaigning

Objective: To present an overview of almost two decades of multi-faceted campaigning by the Belgian Antibiotic Policy Coordination Committee (BAPCOC) and partners, and its impact on public and prescribers' awareness, outpatient antibiotic use, its cost and antimicrobial resistance in Belgium.Methods: Awareness of both public and prescribers was assessed through pre- and post-campaign interviews and surveys. Outpatient antibiotic use was evaluated using national reimbursement data expressed in number of defined daily doses and packages (a good proxy for treatments) per 1000 inhabitants per day (DID and PID, respectively) from July 1997 to June 2018. Its cost was studied using the same data expressed in number of euros per 1000 inhabitants per day. Antimicrobial resistance was evaluated between 1986 and 2017 using national data on the proportion of Streptococcus pneumoniae isolates not susceptible to penicillins, macrolides and tetracyclines.Results: Antibiotic awareness improved significantly, with general practitioners preferred by 87.5% of respondents as source of information. The Belgian outpatient antibiotic use has decreased by 12.8% in DID and by 42.8% in PID in the 2017-2018 winter compared to the winter before the start of its public awareness campaigns (1999-2000). This evolution coincided with decreasing costs for antibiotics and decreasing antimicrobial resistance. Despite multi-faceted campaigning, outpatient antibiotic use and use of broad-spectrum antibiotics, especially fluoroquinolones and amoxicillin with clavulanic acid, are still high in Belgium.Conclusion: Almost two decades of multi-faceted campaigning coincide with improvements in antibiotic awareness among the public and prescribers, outpatient antibiotic use and resistance. Nevertheless, additional efforts are needed to reach the targets set in BAPCOC's national action plan 2014-2019. Therefore, a new national action plan was developed for 2020-2024 using a One Health approach.

First Emergence of Resistance to Macrolides and Tetracycline Identified in Mannheimia haemolytica and Pasteurella multocida Isolates from Beef Feedlots in Australia

Bovine respiratory disease (BRD) causes high morbidity and mortality in beef cattle worldwide. Antimicrobial resistance (AMR) monitoring of BRD pathogens is critical to promote appropriate antimicrobial stewardship in veterinary medicine for optimal treatment and control. Here, the susceptibility of Mannheimia haemolytica and Pasteurella multicoda isolates obtained from BRD clinical cases (deep lung swabs at post-mortem) among feedlots in four Australian states (2014-2019) was determined for 19 antimicrobial agents. The M. haemolytica isolates were pan-susceptible to all tested agents apart from a single macrolide-resistant isolate (1/88; 1.1%) from New South Wales (NSW). Much higher frequencies of P. multocida isolates were resistant to tetracycline (18/140; 12.9%), tilmicosin (19/140; 13.6%), tulathromycin/gamithromycin (17/140; 12.1%), and ampicillin/penicillin (6/140; 4.6%). Five P. multocida isolates (3.6%), all obtained from NSW in 2019, exhibited dual resistance to macrolides and tetracycline, and a further two Queensland isolates from 2019 (1.4%) exhibited a multidrug-resistant phenotype to ampicillin/penicillin, tetracycline, and tilmicosin. Random-amplified polymorphic DNA (RAPD) typing identified a high degree of genetic homogeneity among the M. haemolytica isolates, whereas P. multocida isolates were more heterogeneous. Illumina whole genome sequencing identified the genes msr(E) and mph(E)encoding macrolide resistance, tet(R)-tet(H) or tet(Y) encoding tetracycline resistance, and blaROB-1 encoding ampicillin/penicillin resistance in all isolates exhibiting a corresponding resistant phenotype. The exception was the tilmicosin-resistant, tulathromycin/gamithromycin-susceptible phenotype identified in two Queensland isolates, the genetic basis of which could not be determined. These results confirm the first emergence of AMR in M. haemolytica and P. multocida from BRD cases in Australia, which should be closely monitored.

Molecular Characterization of, and Antimicrobial Resistance in, Clostridioides difficile from Thailand, 2017-2018

Antimicrobial resistance (AMR) plays an important role in the pathogenesis and spread of Clostridioides difficile infection (CDI). Many antimicrobials, such as fluoroquinolones, have been associated with outbreaks of CDI globally. This study characterized AMR among clinical C. difficile strains in Thailand, where antimicrobial use remains inadequately regulated. Stool samples were screened for tcdB and positives were cultured. C. difficile isolates were characterized by toxin profiling and PCR ribotyping. Antimicrobial susceptibility testing was performed by agar incorporation, and whole-genome sequencing and AMR genotyping were performed on a subset of strains. There were 321 C. difficile strains isolated from 326 stool samples. The most common toxigenic ribotype (RT) was RT 017 (18%), followed by RTs 014 (12%) and 020 (7%). Resistance to clindamycin, erythromycin, moxifloxacin, and rifaximin was common, especially among RT 017 strains. AMR genotyping revealed a strong correlation between resistance genotype and phenotype for moxifloxacin and rifaximin. The presence of erm-class genes was associated with high-level clindamycin and erythromycin resistance. Point substitutions in the penicillin-binding proteins were not sufficient to confer meropenem resistance, but a Y721S substitution in PBP3 was associated with a 4.37-fold increase in meropenem minimal inhibitory concentration. No resistance to metronidazole, vancomycin, or fidaxomicin was observed.

Multiresidue determination of antibiotics in ready-to-eat duck eggs marketed through e-commerce stores in China and subsequent assessment of dietary risks to consumers

In this work, the occurrence of 34 common antibiotic (15 sulfonamides and 19 quinolones) residues were evaluated in 236 ready-to-eat duck eggs (salted and preserved duck eggs) marketed through e-commerce stores by ultra-performance liquid chromatography coupled to tandem mass spectrometry, and subsequent dietary risk assessments for Chinese consumers were conducted. Among violated positives in duck egg samples, 11 analytes were found including sulfamethazine, sulfaquinoxaline, sulfamethoxazole, sulfadiazine, sulfamonomethoxine, ciprofloxacin, enrofloxacin, ofloxacin, flumequine, sarafloxacin, and nalidixic acid. A higher number of antibiotics were detected in salted duck eggs (five sulfonamides and six quinolones) than in preserved duck eggs (one sulfonamide and two quinolones). The maximum contamination of sulfonamides and quniolones was 448.0 µg/kg (sulfaquinoxaline) and 563.7 µg/kg (enrofloxacin) in salted duck eggs, respectively. Dietary exposure was evaluated through the estimated daily intake (EDI) of risky antibiotics (sulfamethazine, ciprofloxacin, and enrofloxacin) and hazard quotients (HQs). The results showed that EDIs and HQs were in the range of 0.0004 to 0.0099 µg/kg bw/day and 0.0009 to 0.1594%, respectively. The risk was low since HQs obtained were less than 100%. However, a special attention should be paid to ready-to-eat duck egg products high percentile consumers with the prosperity of e-commerce market in China. PRACTICAL APPLICATION: The present analytical method could be used for multiresidue determination of antibiotics in ready-to-eat duck eggs, and dietary risk assessments of risky antibiotics provided a support for the work of regulatory bodies to conduct surveillance programs regarding food safety evaluation of ready-to-eat foods.

Prevalence and Characterization of Quinolone-Resistance Determinants in Escherichia coli Isolated from Food-Producing Animals and Animal-Derived Food in the Philippines

Antimicrobial resistance to quinolones, which constitutes a threat to public health, has been increasing worldwide. In this study, we investigated the prevalence of quinolone-resistant determinants in Escherichia coli not susceptible to quinolones and isolated from food-producing animals and food derived from them, in the Philippines. A total of 791 E. coli strains were isolated in 56.4% of 601 beef, chicken, pork, egg, and milk samples, as well as environmental, cloacal, and rectal swab-collected samples from supermarkets, open markets, abattoirs, and poultry, swine, and buffalo farms. Using the disc diffusion method, it was determined that 78.6% and 55.4% of the isolates were resistant to at least one antimicrobial and multiple drugs, respectively. In 141 isolates not susceptible to quinolones, 115 (81.6%) harbored quinolone-resistant determinants and had mutations predominantly in the quinolone-resistance determining regions (QRDRs) of gyrA and parC. Plasmid-mediated, quinolone resistance (PMQR) and Qnr family (qnrA1, qnrB4, and qnrS1) genes were detected in all isolates. Forty-eight sequence types were identified in isolates harboring mutations in QRDR and/or PMQR genes by multilocus sequence typing analysis. Moreover, 26 isolates harboring mutations in QRDR and/or PMQR genes belonged mostly to phylogroup B1 and Enteroaggregative E. coli. In conclusion, a high prevalence of E. coli was found in food-producing animals and products derived from them, which could potentially spread high-risk clones harboring quinolone-resistance determinants.

Increase and Change in the Pattern of Antibiotic Use in Serbia (2010-2019)

The aim of this study was to determine and describe trends in antibiotics utilization in Serbia over a ten-year period. Data were retrieved from publicly available annual reports (2010-2019). The results were expressed as Defined Daily Dose (DDD) per 1000 inhabitants per day (DID). All calculations were performed using the DDD values for the 2020 Anatomical Therapeutic Chemical/Defined Daily Dose (ATC/DDD) version for each year of the study, to account for the DDD changes during the study period. Antibiotics were classified using the WHO Access, Watch, Reserve (AWaRe) classification. Total utilization of antibacterials for systemic use increased from 17.25 DID in 2010 to 28.65 DID in 2019. A statistically significant increasing trend in the use of the Watch category antibiotics was observed. A tendency towards use of broad-spectrum antibiotics, apparent by a statistically significant increase in the rate of utilization of broad-spectrum macrolides, quinolones and third-generation cephalosporins vs. narrow-spectrum ones, as well as a significant increasing trend in the use of quinolones was identified. Total antibiotic utilization was found to be well above the European average. Several specific problem areas were identified, which requires further efforts to improve antibiotic prescribing. The present study provides the information needed to facilitate antibiotic stewardship in Serbia further and proposes specific interventions to optimize antibiotic use in Serbia.

Comparison of Phenotypical Antimicrobial Resistance between Clinical and Non-Clinical E. coli Isolates from Broilers, Turkeys and Calves in Four European Countries

Livestock data on antimicrobial resistance (AMR) are commonly collected from bacterial populations of clinical and non-clinical isolates. In contrast to data on non-clinical isolates from livestock, data on clinical isolates are not harmonized in Europe. The Normalized Resistance Interpretation (NRI) method was applied to overcome the lack of harmonization of laboratory methods and interpretation rules between monitoring systems. Statistical analyses were performed to identify associations between the isolate type (clinical vs. non-clinical) and resistance to four antimicrobials (ampicillin, tetracycline, gentamicin, and nalidixic acid) per animal category in Germany and France. Additional statistical analyses comparing clinical and non-clinical isolates were performed with the available data on the same antimicrobial panel and animal categories from the UK and Norway. Higher resistance prevalence was found in clinical isolates compared to non-clinical isolates from calves to all antimicrobials included in Germany and France. It was also found for gentamicin in broilers from France. In contrast, in broilers and turkeys from Germany and France and in broilers from the UK, a higher resistance level to ampicillin and tetracycline in non-clinical isolates was encountered. This was also found in resistance to gentamicin in isolates from turkeys in Germany. Resistance differed within countries and across years, which was partially in line with differences in antimicrobial use patterns. Differences in AMR between clinical and non-clinical isolates of Escherichia coli are associated with animal category (broiler, calf, and turkey) and specific antimicrobials. The NRI method allowed comparing results of non-harmonized AMR systems and might be useful until international harmonization is achieved.

A history of antimicrobial drugs in animals: Evolution and revolution

The evolutionary process of antimicrobial drug (AMD) uses in animals over a mere eight decades (1940-2020) has led to a revolutionary outcome, and both evolution and revolution are ongoing, with reports on a range of uses, misuses and abuses escalating logarithmically. As well as veterinary therapeutic perspectives (efficacy, safety, host toxicity, residues, selection of drug, determination of dose and measurement of outcome in treating animal diseases), there are also broader, nontherapeutic uses, some of which have been abandoned, whilst others hopefully will soon be discontinued, at least in more developed countries. Although AMD uses for treatment of animal diseases will continue, it must: (a) be sustainable within the One Health paradigm; and (b) devolve into more prudent, rationally based therapeutic uses. As this review on AMDs is published in a Journal of Pharmacology and Therapeutics, its scope has been made broader than most recent reviews in this field. Many reviews have focused on negative aspects of AMD actions and uses, especially on the question of antimicrobial resistance. This review recognizes these concerns but also emphasizes the many positive aspects deriving from the use of AMDs, including the major research-based advances underlying both the prudent and rational use of AMDs. It is structured in seven sections: (1) Introduction; (2) Sulfonamide history; (3) Nontherapeutic and empirical uses of AMDs (roles of agronomists and veterinarians); (4) Rational uses of AMDs (roles of pharmacologists, clinicians, industry and regulatory controls); (5) Prudent use (residue monitoring, antimicrobial resistance); (6) International and inter-disciplinary actions; and (7) Conclusions.

Antimicrobial resistance and genomic characterisation of Escherichia coli isolated from caged and non-caged retail table eggs in Western Australia

Foodborne exposure to antimicrobial-resistant bacteria is a growing global health concern. Escherichia coli (E. coli) is well recognised as an indicator of food contamination with faecal materials. In the present study, we investigated the occurrence of E. coli in table eggs sold at retail supermarkets in Western Australia (WA). A total of 2172 visually clean and intact retail eggs were purchased between October 2017 and June 2018. A single carton containing a dozen eggs was considered as a single sample resulting a total of 181 samples. The shells and contents of each sample were separately pooled and tested using standard culture-based methods. Overall, generic E. coli was detected in 36 (19.8%; 95% confidence interval: 14.3; 26.4) of the 181 tested retail egg samples. We characterised 100 of the recovered E. coli isolates for their phenotypic antimicrobial resistance using minimum inhibitory concentration (MIC). A subset of E. coli isolates (n = 14) were selected on the basis of their MIC patterns, and were further characterised using whole genome sequencing (WGS). Fifty-seven (57%) of the recovered generic E. coli isolates (n = 100) were resistant to at least one of the 14 antimicrobials included in the MIC testing panel, of which 22 isolates (22%) showed multi-class resistance. The highest frequencies of non-susceptibility of E. coli isolated from WA retailed eggs were against tetracycline (49%) and ampicillin (36%). WGS revealed that tet(A) and bla_TEM-1B genes were present in most of the isolates exhibiting phenotypic resistance to tetracycline and ampicillin, respectively. The majority (98%) of the characterised E. coli isolates were susceptible to ciprofloxacin and azithromycin, and none were resistant to the cephalosporin antimicrobials included in the MIC panel. Two isolates demonstrated reduced susceptibility to ciprofloxacin, with MICs of 0.125 and 0.25 mg/L, and WGS revealed the presence of plasmid mediated qnrs1 gene in both isolates. This is the first report on detection of non-wild-type resistance to fluoroquinolones in supermarket eggs in Australia; one of the two isolates was from a cage-laid eggs sample while the other was from a barn-laid retail eggs sample. Fluoroquinolones have never been permitted for use in poultry farms in Australia. Thus, the detection of low-level ciprofloxacin-resistant E. coli in the absence of local antimicrobial selection pressure at the Australian layer farms warrants further research on the potential role of the environment or human-related factors in the transmission of antimicrobial resistance. The results of this study add to the local and global understanding of antimicrobial resistance spread in foods of animal origin.

Absence of high priority critically important antimicrobial resistance in Salmonella sp. isolated from Australian commercial egg layer environments

The development of antimicrobial resistance in foodborne pathogens is a growing public health concern. This study was undertaken to determine the antimicrobial susceptibility of Salmonella enterica subspecies enterica isolated from the Australian commercial egg layer industry. S. enterica subspecies enterica (n=307) isolated from Australian commercial layer flock environments (2015-2018) were obtained from reference, research and State Government laboratories from six Australian states. All Salmonella isolates were serotyped. Antimicrobial susceptibility testing (AST) for 16 antimicrobial agents was performed by broth microdilution. Antimicrobial resistance genes and sequence types (STs) were identified in significant isolates by whole genome sequencing (WGS). Three main serotypes were detected, S. Typhimurium (n=61, 19.9%), S. Senftenburg (n=45, 14.7%) and S. Agona (n=37, 12.1%). AST showed 293/307 (95.4%) isolates were susceptible to all tested antimicrobial agents and all isolates were susceptible to amoxicillin-clavulanate, azithromycin, ceftiofur, ceftriaxone, ciprofloxacin, colistin, florfenicol, gentamicin, kanamycin and trimethoprim-sulfamethoxazole. Low levels of non-susceptibility were observed to streptomycin (2.3%, n=7), sulfisoxazole (2.0%, n=6), chloramphenicol (1.3%, n=4) and tetracycline (1.0%, n=3). Very low levels of non-susceptibility were observed to ampicillin (2/307; 0.7%) and cefoxitin (2/307; 0.7%). Two isolates (S. Havana and S. Montevideo), exhibited multidrug-resistant phenotypes to streptomycin, sulfisoxazole and tetracycline and possessed corresponding antimicrobial resistance genes (aadA4, aac(6')-Iaa, sul1, tetB). One S. Typhimurium isolate was resistant to ampicillin and tetracycline, and possessed both tetA and bla_TEM-1B. WGS also identified these isolates as belonging to ST4 (S. Montevideo), ST578 (S. Havana) and ST19 (S. Typhimurium). The absence of resistance to highest priority critically important antimicrobials as well as the extremely low level of AMR generally among Australian commercial egg layer Salmonella isolates likely reflect Australia's conservative antimicrobial registration policy in food-producing animals and low rates of antimicrobial use within the industry.

Higher prevalence of multidrug-resistant extended-spectrum β-lactamases producing Escherichia coli in unorganized pig farms compared to organized pig farms in Mizoram, India

Aim

The present study was conducted to record the prevalence of multidrug-resistant (MDR), extended-spectrum β-lactamases (ESBLs) producing Escherichia coli from pig population of organized and unorganized farms of Mizoram and to record the presence of ESBLs, non-ESBLs, and integrons.

Materials and Methods

Fecal samples were collected from pigs under organized (n=40) and unorganized (n=58) farms of Mizoram. Samples were processed for isolation and identification of E. coli by conventional techniques, BD Phoenix™ automated bacterial system, and polymerase chain reaction (PCR) based confirmatory test. All the isolates were subjected to antimicrobial sensitivity test by disk diffusion assay and ESBLs production by double-disk synergy test (DDST). The ESBLs producing isolates were subjected to PCR for determination of ESBLs genes and all the isolates were screened for non-ESBLs genes and integrons by PCR.

Results

A total of 258 E. coli was isolated and identified from organized (n=120) and unorganized farms (n=138). Majority of the E. coli isolates exhibited high level of resistance against amoxicillin (Ax) (81.78%), cefalexin (85.42%), co-trimoxazole (50.78%), sulfafurazole (69.38%), tetracycline (65.89%), and trimethoprim (TR) (51.94%). Statistically highly significant (p<0.01) variations in resistance among the isolates from organized and unorganized farms were recorded in case of Ax, ampicillin, cephalexin, ciprofloxacin, co-trimoxazole, gentamicin, piperacillin, and TR. By DDST, 65.89% isolates were recorded as ESBLs producer, of which 82/120 (68.33%) and 88/138 (63.77%) were from organized and unorganized farms, respectively. A total of 29/258 (11.24%) isolates were positive for at least one ESBLs gene. bla_TEM was most frequently (9.69%) gene, followed by bla_CTX -M (5.04%) and bla_CMY (0.78%). Altogether, 6 (5.00%), 4 (3.33%), and 2 (1.67%) isolates from the organized farms were positive for bla_CTX-M , bla_TEM , and bla_CMY genes, respectively. Similarly, 21 (15.22%) and 7 (5.07%) isolates from the unorganized farms were positive for bla_TEM and bla_CTX-M genes, respectively. None of them were positive for bla_SHV genes. Altogether 57 (22.09%), 9 (3.49%), 66 (25.58%), 78 (30.23%), 21 (8.14%), and 18 (6.98%) isolates were positive for tetA, tetB, sul1, sul2, aadA, and dfrla genes, respectively. The prevalence of non-ESBLs genes was higher in the E. coli isolates from the unorganized farms than organized farms.

Conclusion

MDR and ESBLs producing E. coli are circulating among the pigs and their environment in Mizoram. Pigs under unorganized farms exhibited higher level of resistance against majority of the antimicrobials, including third-generation cephalosporins, which might be an indication of overuse or misuse of antibiotics under the unorganized piggery sectors in Mizoram.

Phenotypical antimicrobial resistance data of clinical and non-clinical Escherichia coli from poultry in Germany between 2014 and 2017

Antimicrobial resistance (AMR) is a global threat in humans and animals, and antimicrobial usage (AMU) has been identified as a main trigger of AMR. The purpose of this work was to compare data on AMR in clinical and non-clinical isolates of Escherichia coli in German broilers and turkeys between 2014 and 2017. Furthermore, we investigated AMR changes over time and the association of changes in AMU with changes in AMR. Data on clinical and non-clinical isolates together with data on therapy frequency of broilers and turkeys were collected from German monitoring systems. Logistic regression analyses were performed to assess the association between the explanatory factors (AMU, year and isolate type) and the dependent variable (AMR). In broilers, the analysis showed lower resistance proportions of clinical isolates of E. coli to ampicillin and colistin (ampicillin: Odds ratio (OR) and 95% confidence interval (CI) = 0.44 (0.3-0.64), p<0.001; colistin: OR and 95% CI = 0.75 (0.73-0.76), p<0.001) but higher proportions for cefotaxime (OR and 95% CI = 4.58 (1.56-15.1), p = 0.007). Resistance to ampicillin, gentamicin and tetracycline was less frequent in clinical isolates in turkeys (ampicillin: OR and 95% CI = 0.4 (0.29-0.53), p<0.001; gentamicin: OR and 95% CI = 0.5 (0.26-0.94), p = 0.035; tetracycline: OR and 95% CI = 0.4 (0.29-0.55), p<0.001). The analysis found decreasing associations of AMU with resistance to tetracycline in turkeys and to colistin in broilers. Year was associated with a decrease in resistance to colistin in broilers and to tetracycline in turkeys. Differences in resistance found in this study between clinical and non-clinical isolates might play an important role in resistance prevalence. This study indicated that further data analyses over longer time intervals are required to clarify the differences found between clinical and non-clinical isolates and to assess the long-term effects of changes in AMU on the prevalence of AMR.