Prevalence and Antimicrobial Resistance of Enterobacteriaceae in Shell Eggs from Small-Scale Poultry Farms and Farmers' Markets

Preliminary snapshot reveals a relationship between multidrug-resistance and biofilm production among enterobacteriaceae isolated from fecal samples of farm-raised poultry in ceará, Brazil

Antimicrobial resistance and biofilm formation by microbial pathogens pose a significant challenge to poultry production systems due to the persistent risk of dissemination and compromise of bird health and productivity. In this context, the study aimed to investigate the occurrence of different multiresistance phenotypes and the biofilm-forming ability of Enterobacteriaceae isolated from broiler chicken excreta in poultry production units in Ceará, Brazil. Samples were collected from three distinct broiler breeding facilities and subjected to isolation, identification, antibiotic susceptibility testing, phenotypic screening for β-lactamases enzymes, and biofilm formation evaluation. Seventy-one strains were identified, being Escherichia coli (37 %) and Proteus mirabilis (32 %), followed by Klebsiella pneumoniae (11 %), Providencia stuartii (9 %), Klebsiella aerogenes (6 %), Alcaligenes faecalis (4 %), and Salmonella sp. (1 %). A significant proportion (87 %) of multiresistant strains were detected. For the phenotypic evaluation of β-lactamases production, strains with resistance to second and third-generation cephalosporins and carbapenems were tested. About 4 of 6 and 10 of 26 were positive for inducible chromosomal AmpC β-lactamase and extended-spectrum β-lactamase (ESBL), respectively. Regarding biofilm formation, it was observed that all MDR strains were capable of forming biofilm. In this sense the potential of these MDR bacteria to develop biofilms becomes a significant concern, representing a real threat to both human and animal health, as biofilms offer stability, antimicrobial protection, and facilitate genetic transfer.

Emergence of tet(X4)-positive Enterobacterales in retail eggs and the widespread of IncFIA(HI1)-HI1A-HI1B(R27) plasmids carrying tet(X4)

The proliferation of antimicrobial-resistant microbes and resistance genes in various foods poses a serious hazard to public health. The plasmid-mediated tigecycline resistance gene tet(X4) has been detected in Enterobacterales from various niches but has not yet been reported in eggs. This study aimed to investigate the occurrence and characteristics of tigecycline-resistant strains from retail eggs. A total of 144 eggs were purchased from farmers' markets in Guangdong province, China, and eggshell (n = 144) and egg content (n = 96) samples were used to screen for tigecycline-resistant strains. Eight Escherichia coli strains (two ST195, one ST48, ST8165, ST752, ST93, ST189, and ST224) and one Klebsiella pneumoniae strain (ST252) recovered from eight (5.56 %, 8/144) egg samples (eggshells, n = 6; egg content, n = 2) were positive for tet(X4). Notably, the two E. coli ST195 strains were closely (15-54 SNPs) related to all the tet(X4)-positive E. coli ST195 from various origins (food animals, foods, migratory birds, human, and environment) deposited in GenBank. The E. coli ST224 showed a close phylogenetic relationship (9-12 SNPs) with two tet(X4)-positive E. coli strains from chicken feces and retail chicken in Guangdong province. The hybrid plasmid IncFIA(HI1)-HI1A-HI1B(R27) constitutes the predominant tet(X4) vector both herein (7/9, 77.78 %) and in the GenBank database (32/160, 20 %). The tet(X4)-positive IncFIA(HI1)-HI1A-HI1B(R27) plasmids, sharing highly similar structures, have been widely disseminated across China. However, the IncFIA(HI1)-HI1A-HI1B(R27) plasmids exhibit poor stability and low conjugation frequency. The contamination of tet(X4)-positive bacteria internally and externally in retail eggs poses a prospective food safety threat. More attention should be paid to the spread of the tet(X4) gene via epidemic clone E. coli ST195 and the plasmid IncFIA(HI1)-HI1A-HI1B(R27).

Bacteria and antibiotic resistance detection in fractures of wild birds from wildlife rehabilitation centres in Spain

Anatomic adaptations make birds more prone to open fractures with exposed bone parts losing vascularization. As a result of this exposure, fractures are colonized by different microorganisms, including different types of bacteria, both aerobic and anaerobic, causing osteomyelitis in many cases. For this reason, antibiotic treatment is common. However, carrying out antibiotic treatment without carrying out a previous antibiogram may contribute to increased resistance against antibiotics, especially in migratory wild birds. In this paper, bacterial counts regarding fracture type, bacterial identification and antibiotic resistance have been analysed in wild birds from wildlife rehabilitation centres in Spain. The results obtained showed that open fractures had higher bacterial counts (CFU/mL) than closed ones. Bacteria in family Enterobacteriaceae, identified were Escherichia spp., Enterobacter spp., Shigella spp., Hafnia alvei, Proteus mirabilis, Leclercia adecarboxylata and Pantoea agglomerans. Other bacteria present in wild birds' fractures were Aeromonas spp., Enterococcus spp. Bacillus wiedmannii and Staphylococcus sciuri. All species found presented resistance to at least one of the antibiotics used. Wild birds can be implicated in the introduction, maintenance and global spreading of antibiotic resistant bacteria and represent an emerging public health concern. Results obtained in this paper support the idea that it is necessary to take this fact into account before antibiotic administration to wild animals, since it could increase the number of bacteria resistant to antibiotics.

Whole genome sequence comparison of avian pathogenic Escherichia coli from acute and chronic salpingitis of egg laying hens

BACKGROUND

Infection in the oviduct (salpingitis) is the most common bacterial infection in egg laying hens and is mainly caused by Escherichia coli. The disease is responsible for decreased animal welfare, considerable economic loss as well as a risk of horizontal and vertical transmission of pathogenic E. coli. The outcome of salpingitis may be either acute or chronic. It has not yet been clarified whether the pathological manifestation is a result of the characteristics of the E. coli or whether the manifestation is associated with host factors such as host immunity.

RESULTS

From the core- and accessory genome analysis and comparison of 62 E. coli no genetic markers were found to be associated to either acute or chronic infection. Twenty of the 62 genomes harboured at least one antimicrobial resistance gene with resistance against sulfonamides being the most common. The increased serum survival and iron chelating genes iss and iroN were highly prevalent in genomes from both acute and chronic salpingitis.

CONCLUSION

Our analysis revealed that no genetic markers could differentiate the E. coli isolated from acute versus chronic salpingitis in egg laying hens. The difference in pathological outcome may be related to other factors such as immunological status, genetics and health of the host. These data indicate that salpingitis is another manifestation of colibacillosis.

Comparison and assessment of necropsy lesions in end-of-lay laying hens from different housing systems in Denmark

Apperantly healthy laying hens at the end of production (60 to 91 wk) were investigated for the occurrence of pathology and bacterial infections. In total, 7,477 hens from 15 flocks representing the following production systems: Enriched cages, barn housed layers, and organic/free range layers were necropsied. Indications of bacterial infection were investigated by bacteriological cultivation. The overall prevalence of lesions was 16.60%, including lesions of both infectious and non-infectious origin. The most prevalent lesions were bursitis presternalis (6.65%), reproductive tract lesions (e.g., salpingitis and/or peritonitis and/or oophoritis) (3.50%), serosal scarification (e.g., fibrotic adhesive peritonitis) 1.55%, and neoplasm 1.73%. Significant differences were observed between different production systems and/or flocks in the prevalence of reproductive tract lesions, bursitis presternalis, serosal scarification, skin infections, juvenile hens, and traumas/fractures. No significant difference was observed between different production systems in the prevalence of neoplasia, infection of septicemic etiology, and pododermatitis. In total, 3.4% of the hens were out of lay, with significantly higher rate in organic flocks. Infections of the reproductive tract were the most prevalent lesions with bacterial etiology in all productions systems. In total, 40% of the hens with lesions associated to the oviduct were out of lay and significant difference between production systems were observed. Escherichia coli was the most commonly isolated bacteria and in 90% of the cases they were isolated from the reproductive tract lesions. The second most prevalent bacteria was Gallibacteruim anatis. Significant difference in the prevalence of E. coli positive hens was observed between production systems (P < 0.05). In conclusion, the prevalence of reproductive tract lesions in apparently healthy end-of-lay laying was higher than indicated in previous reports. These findings support the previous suggestions that E. coli and G. anatis are the major pathogens causing reproductive tract lesions.

Antimicrobial-resistant Staphylococcus aureus and MRSA prevalence among Korean families and household items

One-hundred-and-seventy-nine Staphylococcus aureus strains, collected from a total of 825 resident and household item samples in Korean homes nationwide, were tested, to survey the spread of antimicrobial-resistant S. aureus including the methicillin-resistant S. aureus (MRSA) strain. Antimicrobial resistance to sulfamethoxazole-trimethoprim (0.0%), teicoplanin (0.0%), tetracycline, vancomycin (0.0%,) chloramphenicol (0.0%), ciprofloxacin (1.1%), clindamycin (1.1%), amikacin (2.2%), gentamicin (8.4%), oxacillin (17.9%), erythromycin (21.8%), ampicillin (96.6%) and penicillin (96.6%), was detected by disk diffusion method and 7.3% (13/179) of the antimicrobial-resistant isolates, were multi-drug resistant (resistant to ≥3 antimicrobial classes). Nine of 32 oxacillin-resistant strains, were positive for the mecA gene and identified as MRSA, in 4 residents and 4 loofah samples, by polymerase chain reaction. These findings provide public health information and contribute to preventing circulation of antimicrobial-resistant strains in community settings including healthy homes.