Antimicrobial Susceptibility Profiles of Commensal Staphylococcus spp. Isolates from Chickens in Hungarian Poultry Farms Between 2022 and 2023

BACKGROUND

Antimicrobial resistance is one of the greatest challenges of our time, urging researchers in both veterinary and public health to engage in collaborative efforts, thereby fostering the One Health approach. Infections caused by Staphylococcus species can not only lead to significant diseases in poultry but also pose serious threats to human life, particularly in hospital (nosocomial) infections; therefore, it is crucial to identify their antimicrobial resistance.

METHODS

Our objective was to assess the susceptibility profile of commensal Staphylococcus aureus strains (n = 227) found in commercial chicken flocks in Hungary through the determination of minimum inhibitory concentration (MIC) values.

RESULTS

Based on our findings, resistance to tiamulin (82.8%; 95% CI: 77.4-87.2%) and doxycycline (74.4%; 95% CI: 68.5-79.7%) is the most critical. The 55.1% (95% CI: 48.8-61.3%) resistance rate to enrofloxacin, a critically important antimicrobial, is also concerning. The fact that 58.6% (95% CI: 52.4-64.5%) of the strains were resistant to amoxicillin and 35.7% (95% CI: 29.7-42.1) were resistant to amoxicillin-clavulanic acid suggests that a proportion of the strains produce β-lactamase. Comparing our results with the available human hospital data, it was found that resistance to macrolide antibiotics is similarly high in both cases.

CONCLUSIONS

Our findings highlight the necessity of conducting regular surveillance studies, which would allow the monitoring of future temporal trends. This information could benefit practitioners making clinical decisions to successfully treat infections. To uncover the underlying causes of multidrug resistance, next-generation sequencing can be employed to elucidate the genetic basis of phenotypic resistance.

Exploring the Interplay of the CRISPR-CAS System with Antibiotic Resistance in Staphylococcus aureus: A Poultry Meat Study from Lahore, Pakistan

Staphylococcus aureus is one of the major pathogens responsible for causing food poisoning worldwide. The emergence of antibiotic resistance in this bacterium is influenced by various factors. Among them, bacterial acquired defense systems described as clustered regularly interspaced short palindromic repeats (CRISPR)-cas system might be involved in antibiotic resistance development in bacteria. The current study was designed to assess the prevalence of S. aureus and its antibiotic resistance profile and identify the relationship of the CRISPR-cas system with antimicrobial resistance, followed by phylogenetic analysis. Total samples (n = 188) of poultry meat were collected from the poultry bird market of Lahore, Punjab, Pakistan. We used both phenotypic (antibiotic disc diffusion) and genotypic methods (PCR) to identify multi-drug resistant (MDR) strains of S. aureus. Additionally, the role of the CRISPR-Cas system in the isolated MDR S. aureus was also assessed. In addition, real-time quantitative PCR (qRT-PCR) was used to evaluate the association of the CRISPR-cas system with antimicrobial resistance. All of the S. aureus isolates showed 100% resistance against erythromycin, 97.5% were resistant to tetracycline, and 75% were resistant to methicillin. Eleven isolates were MDR in the current study. The CRISPR system was found in all MDR isolates, and fifteen spacers were identified within the CRISPR locus. Furthermore, MDR S. aureus isolates and the standard strain showed higher expression levels of CRISPR-associated genes. The correlation of said system with MDR isolates points to foreign gene acquisition by horizontal transfer. Current knowledge could be utilized to tackle antibiotic-resistant bacteria, mainly S. aureus.

Species Profiles and Antimicrobial Resistance of Non-aureus Staphylococci Isolated from Healthy Broilers, Farm Environments, and Farm Workers

Non-aureus staphylococci (NAS), particularly antimicrobial-resistant NAS, have a substantial impact on human and animal health. In the current study, we investigated (1) the species profiles of NAS isolates collected from healthy broilers, farm environments, and farm workers in Korea, (2) the occurrence of antimicrobial-resistant NAS isolates, especially methicillin resistance, and (3) the genetic factors involved in the methicillin and fluoroquinolone resistance. In total, 216 NAS isolates of 16 different species were collected from healthy broilers (n=178), broiler farm environments (n=18), and farm workers (n=20) of 20 different broiler farms. The two most dominant broiler-associated NAS species were Staphylococcus agnetis (23.6%) and Staphylococcus xylosus (22.9%). Six NAS isolates were mecA-positive carrying staphylococcal cassette chromosome mec (SCCmec) II (n=1), SCCmec IV (n=1), SCCmec V (n=2), or non-typeable SCCmec element (n=2). While two mecA-positive Staphylococcus epidermidis isolates from farm workers had SCCmec II and IV, a mecA-positive S. epidermidis isolate from broiler and a Staphylococcus haemolyticus isolate farm environment carried SCCmec V. The occurrence of multidrug resistance was observed in 48.1% (104/216 isolates) of NAS isolates with high resistance rates to β-lactams (>40%) and fusidic acid (59.7%). Fluoroquinolone resistance was confirmed in 59 NAS isolates (27.3%), and diverse mutations in the quinolone resistance determining regions of gyrA, gyrB, parC, and parE were identified. These findings suggest that NAS in broiler farms may have a potential role in the acquisition, amplification, and transmission of antimicrobial resistance.

Horizontal transfer of probable chicken-pathogenicity chromosomal islands between Staphylococcus aureus and Staphylococcus agnetis

Staphylococcus agnetis is an emerging pathogen in chickens but has been most commonly isolated from sub-clinical mastitis in bovines. Previous whole-genome analyses for known virulence genes failed to identify determinants for the switch from mild ductal infections in cattle to severe infections in poultry. We now report identification of a family of 15 kbp, 17-19 gene mobile genetic elements (MGEs) specific to chicken osteomyelitis and dermatitis isolates of S. agnetis. These MGEs can be present in multiple copies per genome. The MGE has been vectored on a Staphylococcus phage that separately lysogenized two S. agnetis osteomyelitis strains. The S. agnetis genome from a broiler breeder case of ulcerative dermatitis contains 2 orthologs of this MGE, not associated with a prophage. BLASTn and phylogenetic analyses show that there are closely related intact MGEs found in genomes of S. aureus. The genome from a 1980s isolate from chickens in Ireland contains 3 copies of this MGE. More recent chicken isolates descended from that genome (Poland 2009, Oklahoma 2010, and Arkansas 2018) contain 2 to 4 related copies. Many of the genes of this MGE can be identified in disparate regions of the genomes of other chicken isolates of S. aureus. BLAST searches of the NCBI databases detect no similar MGEs outside of S. aureus and S. agnetis. These MGEs encode no proteins related to those produced by Staphylococcus aureus Pathogenicity Islands, which have been associated with the transition of S. aureus from human to chicken hosts. Other than mobilization functions, most of the genes in these new MGEs annotate as hypothetical proteins. The MGEs we describe appear to represent a new family of Chromosomal Islands (CIs) shared amongst S. agnetis and S. aureus. Further work is needed to understand the role of these CIs/MGEs in pathogenesis. Analysis of horizontal transfer of genetic elements between isolates and species of Staphylococci provides clues to evolution of host-pathogen interactions as well as revealing critical determinants for animal welfare and human diseases.

Production systems and important antimicrobial resistant-pathogenic bacteria in poultry: a review

Economic losses and market constraints caused by bacterial diseases such as colibacillosis due to avian pathogenic Escherichia coli and necrotic enteritis due to Clostridium perfringens remain major problems for poultry producers, despite substantial efforts in prevention and control. Antibiotics have been used not only for the treatment and prevention of such diseases, but also for growth promotion. Consequently, these practices have been linked to the selection and spread of antimicrobial resistant bacteria which constitute a significant global threat to humans, animals, and the environment. To break down the antimicrobial resistance (AMR), poultry producers are restricting the antimicrobial use (AMU) while adopting the antibiotic-free (ABF) and organic production practices to satisfy consumers' demands. However, it is not well understood how ABF and organic poultry production practices influence AMR profiles in the poultry gut microbiome. Various Gram-negative (Salmonella enterica serovars, Campylobacter jejuni/coli, E. coli) and Gram-positive (Enterococcus spp., Staphylococcus spp. and C. perfringens) bacteria harboring multiple AMR determinants have been reported in poultry including organically- and ABF-raised chickens. In this review, we discussed major poultry production systems (conventional, ABF and organic) and their impacts on AMR in some potential pathogenic Gram-negative and Gram-positive bacteria which could allow identifying issues and opportunities to develop efficient and safe production practices in controlling pathogens.

Targeting therapy effects of composite hyaluronic acid/chitosan nanosystems containing inclusion complexes

In order to solve the difficulties in the treatment of Staphylococcus aureus infections, a novel enrofloxacin-cyclodextrin (β-CD) inclusion complexes (IC) containing hyaluronic acid/chitosan (HA/CS) self-assemble composite nanosystems covered by poloxamer 188 was designed in our previous study. In this study, the sustained release peforemance, targeting delivery, and therapy effects of the enrofloxacin-composite nanosystems were evaluated in vivo. The enrofloxacin-composite nanosystems had uniform size and smooth surface with drug loading capacity (LC) of 9.92 ± 0.3%. Thermogravimetric analysis (TGA) showed that the material used for the preparation of the enrofloxacin-composite nanosystems did not affect the thermal stability of enrofloxacin. Compared with enrofloxacin injection and enrofloxacin polymeric nanoparticles, the enrofloxacin-composite nanosystems had excellent sustained-release performance in vivo. The enrofloxacin-composite nanosystems have specific targeting to the infection site of Staphylococcus aureus. The excellent sustained release and targeting delivery properties ensure that the anti-infective treatment effect of the enrofloxacin-composite nanosystems in vivo was higher than that of enrofloxacin injection and enrofloxacin polymeric nanoparticles. It can more effectively promote the wound healing. These results suggest that our previous designed enrofloxacin-composite nanosystems will be a promising formulation for effective targeting therapy of Staphylococcus aureus infections.

Antimicrobial resistance in the globalized food chain: a One Health perspective applied to the poultry industry

Antimicrobial resistance (AMR) remains a major global public health crisis. The food animal industry will face escalating challenges to increase productivity while minimizing AMR, since the global demand for animal protein has been continuously increasing and food animals play a key role in the global food supply, particularly broiler chickens. As chicken products are sources of low-cost, high-quality protein, poultry production is an important economic driver for livelihood and survival in developed and developing regions. The globalization of the food supply, markedly in the poultry industry, is aligned to the globalization of the whole modern society, with an unprecedented exchange of goods and services, and transit of human populations among regions and countries. Considering the increasing threat posed by AMR, human civilization is faced with a complex, multifaceted problem compromising its future. Actions to mitigate antimicrobial resistance are needed in all sectors of the society at the human, animal, and environmental levels. This review discusses the problems associated with antimicrobial resistance in the globalized food chain, using the poultry sector as a model. We cover critical aspects of the emergence and dissemination of antimicrobial resistance in the poultry industry and their implications to public health in a global perspective. Finally, we provide current insights using the multidisciplinary One Health approach to mitigate AMR at the human-animal-environment interface.

Detection of microbial contamination in chicken meat from local markets in Surabaya, East Java, Indonesia

Background and Aim:

Chicken meat can be contaminated by microorganisms anywhere in the supply chain, from farm to market, and these microorganisms can be transmitted to humans through direct contact, contact with the environment, and food consumption. The microbial contamination has a serious impact on public health. This study aimed to analyze the microbial contamination of chicken meat sampled from local markets in Surabaya, East Java, Indonesia.

Materials and Methods:

A total of 60 samples of fresh chicken meat obtained from 10 traditional markets (six samples per market) were examined for the presence of bacteria. Staphylococcus aureus, Salmonella spp., and Escherichia coli were identified using Gram staining, culturing, and biochemical tests. The most probable number (MPN) method was used to identify E. coli.

Results:

Most chicken meat samples were positive for S. aureus (58.3%), Salmonella spp. (48.3%), and E. coli (40%). The samples were considered positive for E. coli if the MPN value was higher than 1×10¹ CFU/g.

Conclusion:

High microbial contamination was found in all the chicken meat sampled from local markets in Surabaya. Such contamination can lead to foodborne diseases so, proper hygiene and sanitation standards should be followed from slaughterhouses to the end-users.

Prevalence, main serovars and anti-microbial resistance profiles of non-typhoidal Salmonella in poultry samples from the Americas: A systematic review and meta-analysis

Poultry and poultry-derived products such as meat and eggs are among the main sources of non-typhoidal Salmonella (NTS) transmission to humans. Therefore, we performed a systematic review and used random-effects meta-analyses to (1) estimate the prevalence of NTS in poultry samples from birds, products and subproducts and environmental samples, (2) examine the diversity and frequency of their serovars and (3) estimate the prevalence and profiles of anti-microbial resistance (AMR) in NTS isolates reported in studies from the Americas. We included 157 studies from 15 countries comprising 261,408 poultry samples and estimated an overall pooled prevalence of 17.9% (95% Confidence Interval: 10.8-26.3) in birds, 21.8% (17.7-26.1) in products and subproducts and 29.5% (24.2-35.1) in environmental samples. At the national level, the prevalence of NTS was heterogeneous across countries with the highest values in Mexico, the United States and Canada. In total, 131 serovars were identified from 13,388 isolates; Heidelberg, Kentucky, Enteritidis and Typhimurium were the most prevalent in the overall top 10 ranking (range 6.5%-20.8%). At the national level, Enteritidis and Typhimurium were identified in most of the countries, though with national differences in their ranks. The prevalence of AMR increased from 24.1% for 1 antibiotic to 36.2% for 2-3 antibiotics and 49.6% for ≥ 4 antibiotics. Kentucky, Heidelberg, Typhimurium and Enteritidis were the serovars with the highest prevalence of AMR. Besides, tetracycline, ampicillin, streptomycin, ceftiofur and amoxicillin-clavulanic acid were the most frequent antibiotics to which NTS showed resistance. In conclusion, NTS was distributed through the avian production chain with high and heterogeneous values of prevalence in poultry samples. Besides, there were distinctive patterns of serovars distribution across countries and an alarming prevalence of AMR among zoonotic serovars.

Antibiotic Susceptibility of Staphylococcus Species Isolated in Raw Chicken Meat from Retail Stores

The study was aimed at evaluating the presence of antibiotic-resistant Staphylococcus aureus in retailed raw chicken meat from retail stores intended for human consumption. The presence, characterization, and antibiotic susceptibility of S. aureus from 38 retail raw chicken meat samples was performed using a standard microbiological method involving mannitol salt agar (MSA) and Mueller-Hinton agar (MHA). All the samples were positive for Staphylococcus species, of which 34 (89.5%) were positive for S. aureus. The S. aureus isolates were most resistant to tetracycline (88.24%), erythromycin (82.35%), and chloramphenicol (61.77%). Nevertheless, decreased resistance towards gentamycin (23.53%) and cotrimoxazole (38.24%) were recorded. All the S. aureus isolates in this study were resistant to cloxacillin, amoxicillin, and augmentin (amoxicillin + clavulanic acid). The present findings show how the raw chicken meat samples could be a potential source of multidrug-resistant S. aureus strains dissemination. Therefore, this study suggests high-level contamination of meat with multidrug-resistant S. aureus and highlights the public health consequences of consuming such products. Undoubtedly, uncontrolled drugs in food animal production as growth stimulators or medicinal treatment present a possible consequence to people’s health. Having the aforementioned in mind, there is a necessity to control the use of drugs and monitor any residues left in the food intended for human consumption.

Whole-Genome Sequencing and Machine Learning Analysis of Staphylococcus aureus from Multiple Heterogeneous Sources in China Reveals Common Genetic Traits of Antimicrobial Resistance

Staphylococcus aureus is a worldwide leading cause of numerous diseases ranging from food-poisoning to lethal infections. Methicillin-resistant S. aureus (MRSA) has been found capable of acquiring resistance to most antimicrobials. MRSA is ubiquitous and diverse even in terms of antimicrobial resistance (AMR) profiles, posing a challenge for treatment. Here, we present a comprehensive study of S. aureus in China, addressing epidemiology, phylogenetic reconstruction, genomic characterization, and identification of AMR profiles. The study analyzes 673 S. aureus isolates from food as well as from hospitalized and healthy individuals. The isolates have been collected over a 9-year period, between 2010 and 2018, from 27 provinces across China. By whole-genome sequencing, Bayesian divergence analysis, and supervised machine learning, we reconstructed the phylogeny of the isolates and compared them to references from other countries. We identified 72 sequence types (STs), of which, 29 were novel. We found 81 MRSA lineages by multilocus sequence type (MLST), spa, staphylococcal cassette chromosome mec element (SCCmec), and Panton-Valentine leukocidin (PVL) typing. In addition, novel variants of SCCmec type IV hosting extra metal and antimicrobial resistance genes, as well as a new SCCmec type, were found. New Bayesian dating of the split times of major clades showed that ST9, ST59, and ST239 in China and European countries fell in different branches, whereas this pattern was not observed for the ST398 clone. On the contrary, the clonal transmission of ST398 was more intermixed in regard to geographic origin. Finally, we identified genetic determinants of resistance to 10 antimicrobials, discriminating drug-resistant bacteria from susceptible strains in the cohort. Our results reveal the emergence of Chinese MRSA lineages enriched of AMR determinants that share similar genetic traits of antimicrobial resistance across human and food, hinting at a complex scenario of evolving transmission routes. IMPORTANCE Little information is available on the epidemiology and characterization of Staphylococcus aureus in China. The role of food is a cause of major concern: staphylococcal foodborne diseases affect thousands every year, and the presence of resistant Staphylococcus strains on raw retail meat products is well documented. We studied a large heterogeneous data set of S. aureus isolates from many provinces of China, isolated from food as well as from individuals. Our large whole-genome collection represents a unique catalogue that can be easily meta-analyzed and integrated with further studies and adds to the library of S. aureus sequences in the public domain in a currently underrepresented geographical region. The new Bayesian dating of the split times of major drug-resistant enriched clones is relevant in showing that Chinese and European methicillin-resistant S. aureus (MRSA) have evolved differently. Our machine learning approach, across a large number of antibiotics, shows novel determinants underlying resistance and reveals frequent resistant traits in specific clonal complexes, highlighting the importance of particular clonal complexes in China. Our findings substantially expand what is known of the evolution and genetic determinants of resistance in food-associated S. aureus in China and add crucial information for whole-genome sequencing (WGS)-based surveillance of S. aureus.

Efficacy of metal oxide nanoparticles as novel antimicrobial agents against multi-drug and multi-virulent Staphylococcus aureus isolates from retail raw chicken meat and giblets

Staphylococcus aureus is among the most common zoonotic pathogens originating from animals consumed as food, especially raw chicken meat (RCM). As far as we know, this might be the first report that explores the efficacy of metal oxide nanoparticles (MONPs), such as zinc peroxide nanoparticles (ZnO₂-NPs), zinc oxide nanoparticles (ZnO-NPs), and titanium dioxide nanoparticles (TiO₂-NPs) against multidrug resistant (MDR) and/or pandrug resistant (PDR) S. aureus strains with a strong biofilm-producing ability isolated from RCM and giblets. The overall prevalence of coagulase-positive staphylococci was 21%, with a contamination level range between 10² and 10⁴ CFU/g. The incidence of virulence genes See (21/36), pvl (16/36), clfA (15/36), sec (12/36), tst (12/36), and sea (11/36) among S. aureus strains were relatively higher those of seb, sed, fnbA, and fnbB. For antimicrobial resistance gene distribution, most strains harbored the blaZ gene (25/36), aacA-aphD gene (24/36), mecA gene (22/36), vanA gene (20/36), and apmA gene (20/36) confirmed the prevalence of MDR among S. aureus of RCM products. However, cfr (11/36), spc (9/36), and aadE (7/36) showed a relatively lower existence. The data of antibiogram resistance profiles was noticeably heterogeneous (25 patterns) with 32 MDR and four PDR S. aureus strains. All tested strains had a very high MAR index value (>0.2) except the P11 pattern (GEN, MXF, PMB), which showed a MAR index of 0.19. Among the strong biofilm-producing ability (BPA), 14 (70%) strains were isolated from wet markets, while only six strong BPA strains were isolated from supermarkets. The mean values of BPA ranged from 2.613 ± 0.04 to 11.013 ± 0.05. Clearly, ZnO₂-NPs show significant inhibitory activity against S. aureus strains compared with those produced by the action of ZnO-NPs and TiO₂-NPs. The results of anti-inflammatory activity suggest ZnO₂-NPs as a lead compound for designing an alternative antimicrobial agent against drug-resistant and strong biofilm-producing S. aureus isolates from retail RCM and giblets.

Large-Scale Staphylococcus aureus Foodborne Disease Poisoning Outbreak among Primary School Children

A large-scale food poisoning outbreak happened at a school canteen in Ninh Binh Province, Vietnam, in 2018, resulting in the hospitalization of 352 students with clinical symptoms indicative of a staphylococcal food poisoning. A subsequent laboratory investigation detected Staphylococcus aureus in two food items—deep-fried shrimp and chicken floss—at up to 103 CFU/mL, and staphylococcal enterotoxins (SEs) in chicken floss at ≥0.211 ng SEs/g. S. aureus was also isolated from patients’ vomit and stool samples, and kitchen workers’ stool samples, as well as in frozen chicken meat, but not on the kitchen workers’ hand surfaces, suggesting the cause of this food poisoning outbreak was S. aureus contamination of the chicken meat. Molecular characterization revealed the S. aureus strains isolated from all samples were closely related; all belonged to sequence type (ST) ST6 and spa type t701 and carried both sea and sec genes. This SE-producing strain was resistant to penicillin and tetracycline, while still susceptible to oxacillin, erythromycin, gentamicin, methicillin, and vancomycin. Since S. aureus food poisonings are often underreported, our investigation added to the sparse qualitative and quantitative data of pathogenic S. aureus monitoring and surveillance in Vietnam, providing needed knowledge to guide preventative measures for future outbreaks.

Staphylococci in poultry intestines: a comparison between farmed and household chickens

Both pathogenic as well as nonpathogenic species of staphylococci have been reported in poultry, but these studies have not compared staphylococcal flora of both farmed and household broiler chickens. Staphylococci from farmed (n = 51) and household chicken intestines (n = 43) were isolated and tested for resistance to antimicrobials, presence of resistance genes, and inhibitory activity against other bacteria; correlation of resistance phenotype and genotype was also evaluated. At least 12 staphylococcal species were identified; Staphylococcus carnosus subspecies carnosus was the predominant species from both sources. Most farmed chicken staphylococci were resistant to tigecycline (38/51; 74.8%) while the highest level of resistance among the household chicken staphylococci was to clindamycin (31/43; 72.1%). The mecA gene was only detected in staphylococci from household chickens, whereas ermC and tetK or tetM were found in staphylococci from both groups of birds. Multidrug resistance (resistance ≥ 2 antimicrobial classes) was observed in 88% of resistant staphylococci ranging from 2 to 8 classes and up to 10 antimicrobials. Isolates produced inhibitory activity against 7 clinical bacterial strains primarily Enterococcus faecalis (25/88; 28.4%) and Escherichia coli (22/88; 25%). This study demonstrated that the staphylococcal population among farmed and household chickens varies by species and resistance to antimicrobials. These results may reflect the influence of the environment or habitat of each bird type on the intestinal microflora. As resistance in the staphylococci to antimicrobials used to treat human infections was detected, further study is warranted to determine strategies to prevent transfer of these resistant populations to humans via contamination of the poultry meat.

Molecular and phenotypic characterization of Staphylococcus aureus strains isolated from carcass swabs and carcass drips of chickens slaughtered in the informal market in Gauteng Province, South Africa

The study was conducted to characterize Staphylococcus aureus strains from swabs and drips of dressed chicken carcasses sold at outlets in six townships in the informal market in Gauteng province, South Africa, using molecular and phenotypic methods. Seven genes (6 toxins and 1 antimicrobial resistance) comprising staphylococcal enterotoxin A (SEA), B (SEB), C (SEC), D (SED), exfoliative toxin A, toxic shock syndrome toxin, and MecA encoding methicillin resistance were assayed using polymerase chain reaction. The resistance of the S. aureus strains to 18 antimicrobial agents was determined using the disk diffusion method. The frequency of detection of the six toxin genes was sea (52.2%), followed by seb (10.9%), sec (6.5%), sed (2.2%), eta (93.5%), and tst (19.6%). The mecA gene was detected in 4.3% of the isolates. The predominant profiles of toxin genes detected were sea‐eta (37.0%). All 63 isolates of S. aureus were resistant to one or more antimicrobial agents. The frequency of resistance was high to spectinomycin (98.4%), nalidixic acid (85.7%), and penicillin (84.1%), but low to gentamycin (1.6%) and cefotaxime (1.6%). The high frequency of toxin genes and antimicrobial resistance gene observed in S. aureus isolates from chicken could pose a challenge to food safety and may have therapeutic and zoonotic implications.

Genetic characterization of high-level aminoglycoside-resistant Enterococcus faecalis and Enterococcus faecium isolated from retail chicken meat

Retail chicken meat can play a role in the transfer of drug resistance to humans through the handling or ingestion of improperly cooked meat contaminated with resistant enterococci. In fact, high-level aminoglycoside-resistance (HLAR) in enterococci identified in human cases. Therefore, the prevalence and genetic characterization of HLAR in enterococci in retail chicken meat were investigated in this study. Of the 345 enterococci strains, 29 (8.7%) showed HLAR. All HLAR in enterococci carried at least 1 of 2 aminoglycoside-modifying enzyme genes, aac(6')Ie-aph(2″)-Ia and ant(6)-Ia. Among the 13 isolates that carried aac(6')Ie-aph(2″)-Ia, 3 had pattern A, with IS256 at both ends, and the other 10 had pattern D, without IS256 at both ends. All HLAR in enterococci also showed multidrug resistance. Among the 24 erythromycin-resistant enterococci, 19 (79.2%) harbored the ermB gene, and one (4.2%) harbored both the ermB and ermA genes. A total of 21 enterococci were tetracycline-resistant and harbored one or more of the following tetracycline resistance genes tet(M), tet(L), and tet(O). The Int-Tn gene was detected in one isolate (3.4%) carrying the tet(M) and ermB genes. All 4 chloramphenicol-resistant isolates carried either the phenicol resistance gene cfr alone (one isolate), both cfr and fexA (one isolate), or both fexA and optrA (2 isolates). Four efflux pump genes, efr(A), efr(B), emeA, and lsa, were detected in all HLAR in Enterococcus faecalis isolates. These results improve our understanding of the transmission dynamics of HLAR in enterococci from non-hospital sources to humans.

Epidemiological study of sausage in Algeria: Prevalence, quality assessment, and antibiotic resistance of Staphylococcus aureus isolates and the risk factors associated with consumer habits affecting foodborne poisoning

Aim:

The first aim was to assess the quality and determine the prevalence and antibiotic susceptibility of Staphylococcus aureus contamination of raw sausage sold in ten municipalities in the Northeast of Algeria. Second, a consumer sausage purchasing survey was designed to investigate potential risk factors that have a significant association with the occurrence of foodborne poisoning among sausage consumers’ behavior and its relationship with independent variables.

Materials and Methods:

A total of 230 butcheries from ten departments (Daira) of Algiers with more than 40 municipalities were included randomly in these studies to collect raw sausage samples and to distribute 700 structured questionnaires to meat consumers. Our two studies were conducted at the same time, between June 2016 and April 2018. Sausage samples were taken once per butchery to estimate the prevalence of S. aureus contamination and therefore deduct the quality assessment of raw sausage (Merguez) sold in Algiers, Algeria. All isolated strains were tested for their antimicrobial resistance. Furthermore, questionnaires were distributed and used to collect information on various aspects of sausage consumption and foodborne disease. The data collected were analyzed with different statistical approaches, such as the Chi-square test and the odds ratio (OR) univariable logistic model. All the risk factors were analyzed by studying their association with the occurrence of consumers who claimed to have food poisoning after consuming sausage.

Results:

The overall prevalence of S. aureus contamination from sausages was 25.22% (n=58/230). Over 83.33% of strains showed resistance to at least one of the antibiotics tested. The most important was for tetracycline (58%) followed by fosfomycin (33%), penicillin G (25%), and oxacillin (36%). Moreover, the multiple antibiotic resistance (MAR) index include 20 profiles with MAR >0.2. Out of the 440 meat consumers, 22.16% revealed having food poisoning after sausage consumption. The risk factors recorded were: Consumption outside of home (24.30%, OR=1.769, p=0.040), during the summer season (24.30%, OR=1.159) and during lunch (26.50%, OR=1.421).

Conclusion:

Our study highlights a high prevalence of S. aureus contamination in Merguez, especially in some departments of Algiers, and the high multidrug resistance of S. aureus isolates against tetracycline and oxacillin; thus, S. aureus contamination in sausage is considered a potential risk to public health. Therefore, to reduce and prevent the spread of resistant strains, robust management and monitoring of antibiotic use should be established. Therefore, it is necessary to improve the sanitation conditions and education regarding personal hygiene and change certain consumption habits of Algerian consumers to ensure food safety. Finally, it can be concluded that the application of the HACCP system is essential either in butcheries producing sausage and/or slaughterhouses. From this perspective, studies might be performed to characterize Staphylococcus spp and S. aureus to investigate their virulence factors.