Free-Ranging Synanthropic Birds (Ardea alba and Columba livia domestica) as Carriers of Salmonella spp. and Diarrheagenic Escherichia coli in the Vicinity of an Urban Zoo

Abstract

The presence of free-ranging urban birds is a risk factor for transmitting pathogens to captive animals and humans alike, including Salmonella spp. and diarrheagenic Escherichia coli. Cloacal swabs from 156 synanthropic Great egrets (Ardea alba) and feral pigeons (Columba livia domestica) that inhabit the surroundings of an urban zoo were processed for the identification of Salmonella spp. and diarrheagenic E. coli pathotypes. Bacterial species identification and genotypic characterization employed the matrix-assisted laser desorption ionization-time of flight mass spectrometry and PCR techniques, respectively, comparing their phylogenetic profiles through amplified fragment length polymorphism (AFLP) analysis. A total of 11 birds were positive for Salmonella Typhimurium (7%) and 9 individuals (5.8%) for diarrheagenic E. coli (enteropathogenic E. coli/Shiga-toxin producing E. coli [EPEC/STEC]) strains. S. Typhimurium strains presented highly similar AFLP profiles (85-100%), whereas EPEC/STEC strains showed more polymorphism. The results show free-ranging birds as carriers for both microorganisms in a zoo environment in Brazil for the first time and suggest these species as possible sources of infection to other animals as well as exposing personnel and visitors to potential zoonotic microorganisms. The presence of carriers highlights the importance of a surveillance system and the need for preventive measures to avoid attracting growing number of synanthropic avian species.

CTX-M-producing Escherichia coli Isolated from urban pigeons (Columba livia domestica) in Brazil

“…Escherichia coli ATCC 25922 was used as a control. Production of ESBL was assessed by the double-disc synergism technique following the CLSI recommendations [8]. ESBL-producing strains and transconjugants were subjected to determination of minimum inhibitory concentrations (MIC) to cefotaxime, ceftazidime, cefepime, cefoxitin and ceftiofur, using agar dilution methods (mg/L) [11,12].…”

“…Pigeons are considered synanthropic birds due to their minimal feeding requirements and high prolific capacity, leading to overpopulation and conglomeration in urban areas, such as squares, parks, zoos, beaches, and places with food debris. Pigeons cohabit with humans, domestic and wildlife animals, and act as carriers of many emerging pathogens [8]. They have been associated with the occurrence of more than 60 species of bacteria, fungi, virus and protozoans [8,9].…”

“…Pigeons cohabit with humans, domestic and wildlife animals, and act as carriers of many emerging pathogens [8]. They have been associated with the occurrence of more than 60 species of bacteria, fungi, virus and protozoans [8,9]. Synanthropic birds also play an important role as a reservoir of multidrug resistant (MDR) strains.…”

Shiga toxin‐producingEscherichia coliin the animal reservoir and food in Brazil

“…Recently, Oliveira et al () described eae ‐positive STEC strains from pigeons close to a zoo where the stx2f subtype had been detected, which also indicate its increasing importance as a potential human pathogen, including in HUS cases. Additionally, Gioia‐Di Chiacchi et al (, ) reported the detection of tEPEC/STEC hybrid strains isolated from small‐size psittacine birds raised as pets, carrying the stx2f subtype and belonging to the serotype O137:H6, previously associated with HUS.…”

“…Despite low frequencies, ranging from 1·1 to 9·8%, STEC was detected in urban pigeons in MG (Silva et al ), psittacine pet birds in home environments in SP (Gioia‐Di Chiacchio et al ) and in free‐living wild birds and pigeons in SP (Borges et al ; Sanches et al ; Oliveira et al ).…”