Determination of antibiotic resistance patterns and genotypes of Escherichia coli isolated from wild birds.

BACKGROUND: Curbing the potential negative impact of antibiotic resistance, one of our era's growing global public health crises, requires regular monitoring of the resistance situations, including the reservoir of resistance genes. Wild birds, a possible bioindicator of antibiotic resistance, have been suggested to play a role in the dissemination of antibiotic-resistant bacteria. Therefore, this study was conducted with the objective of determining the phenotypic and genotypic antibiotic resistance profiles of 100 Escherichia coli isolates of gull and pigeon origin by using the Kirby-Bauer disk diffusion method and PCR. Furthermore, the genetic relationships of the isolates were determined by RAPD-PCR. RESULTS: Phenotypic antibiotic susceptibility testing revealed that 63% (63/100) and 29% (29/100) of E. coli isolates were resistant to at least one antibiotic and multidrug-resistant (MDR), respectively. With the exception of cephalothin, to which the E. coli isolates were 100% susceptible, tetracycline (52%), kanamycin (38%), streptomycin (37%), ampicillin (28%), chloramphenicol (21%), trimethoprim/sulfamethoxazole (19%), gentamicin (13%), enrofloxacin (12%) and ciprofloxacin (12%) resistances were detected at varying degrees. Among the investigated resistance genes, tet(B) (66%), tet(A) (63%), aphA1 (48%), sul3 (34%), sul2 (26%), strA/strB (24%) and sul1 (16%) were detected. Regarding the genetic diversity of the isolates, the RAPD-PCR-based dendrograms divided both pigeon and gull isolates into five different clusters based on a 70% similarity threshold. Dendrogram analysis revealed 47-100% similarities among pigeon-origin strains and 40-100% similarities among gull-origin E.coli strains. CONCLUSIONS: This study revealed that gulls and pigeons carry MDR E. coli isolates, which may pose a risk to animal and human health by contaminating the environment with their feces. However, a large-scale epidemiological study investigating the genetic relationship of the strains from a "one health" point of view is warranted to determine the possible transmission patterns of antibiotic-resistant bacteria between wild birds, the environment, humans, and other hosts. Video Abstract.

Campylobacter in Wild Birds: Is It an Animal and Public Health Concern?

Campylobacteriosis continues to be one of the leading causes of foodborne bacterial zoonotic infections worldwide. Despite its public health importance, the status of this disease in wild birds and the possibility of transmission from wild birds to domestic animals and humans have not been clearly elucidated yet. This article reviews the available literature with the aim of making a comprehensive manuscript on this disease status in wild birds and the possibility of interspecies transmission. Campylobacter has been isolated from various species of wild birds worldwide, with C. jejuni being the most commonly isolated species. The prevalence of Campylobacter in wild birds may vary depending on several factors like geographical location, season, the bird's health status, bird species, sample type, the method used, and ecological factors. Molecular studies over the past two to three decades have characterized Campylobacter strains isolated from wild birds and have come up with results that fall into two categories. The first are those that report overlapping strains among human, domestic animal, and wild bird isolates. The results of the studies under this category emphasize that wild birds carry strains of Campylobacter, which are indistinguishable from domestic animals and humans and are therefore an important public and animal health concern. In contrast, the studies under the second category highlight significant differences in Campylobacter population structure among these hosts. Despite the controversiality and the inadequacy of current research to draw a full conclusion, the role of wild birds in the epidemiology of Campylobacter should not be undermined as drug-resistant strains, especially resistance to tetracycline and fluoroquinolones, are increasingly documented. In addition, source attribution studies have linked human cases of Campylobacter infections to wild birds. Therefore, the role of wild birds in the epidemiology of Campylobacter infection should not be neglected. However, in order to determine disease status in wild birds and the precise role of wild birds in domestic animals and human health, detail-oriented epidemiological investigations characterizing the genetic relatedness of isolates from the respective species and environment through one health approach are warranted.

Classical enterotoxigenic characteristics of Staphylococcus aureus strains isolated from bovine subclinical mastitis in Van, Turkey.

The aim of the present study was to investigate classical enterotoxigenic properties of Staphylococcus aureus strains isolated from cows with subclinical mastitis. For this purpose, 480 milk samples from cows with subclinical mastitis raised in different villages neighbouring Van city Center were collected. A total of 106 S. aureus strains were isolated. Twenty seven isolates (25.5%) were found to be enterotoxigenic by reverse passive latex agglutination (RPLA). Of these, 25 (23.6%) were positive for staphylococcal enterotoxin A (SEA), 2 (1.9%) for SEB. None of the isolates was positive for SEC or SED. This study showed that most S. aureus strains isolated from bovine subclinical mastitis produced SEA compared to other SEs.

Evolution of slime production by coagulase-negative staphylococci and enterotoxigenic characteristics of Staphylococcus aureus strains isolated from various human clinical specimens.

The present study was designed to determine the slime production of coagulase-negative staphylococci (CoNS) and the enterotoxigenic properties of Staphylococcus aureus strains, and to evaluate the clinical importance of slime-producing CoNS and enterotoxigenic S. aureus strains isolated from various human clinical specimens. For this purpose, a total of 120 Staphylococcus strains were isolated and identified, and further characterized for their slime production and enterotoxigenicity. Of the clinical isolates, 55 (45.8 %) were found to be S. aureus, and the others (54.2 %) were identified as CoNS. Of the CoNS, 20 (16.7 %) were further identified as Staphylococcus hominis, 18 (15 %) as Staphylococcus epidermidis, six (5 %) as Staphylococcus xylosus, six (5 %) as Staphylococcus warneri, five (4.2 %) as Staphylococcus sciuri, four (3.3 %) as Staphylococcus haemolyticus, and two each (1.7 %) as Staphylococcus simulans, Staphylococcus capitis and Staphylococcus saprophyticus, respectively. Thirty-nine (60 %) of 65 CoNS were found to be slime producers. Slime production was observed in all CoNS, except S. capitis, mostly from blood (38.5 %), tracheal aspiration (20.5 %) and urine (12.8 %) specimens. In addition, of the 55 S. aureus isolates, 46 (83.6 %) were found to be enterotoxigenic, and of these S. aureus strains, 39 (84.7 %) were positive for staphylococcal enterotoxin (SE)A. The results of this study showed that the slime-producing CoNS were mostly found in clinical specimens of blood, tracheal aspirate and urine. SEA was the predominant enterotoxin type detected in S. aureus strains from human clinical specimens.