Multidrug-Resistant Proteus mirabilis and Other Gram-Negative Species Isolated from Native Egyptian Chicken Carcasses

Abstract

Poultry carcasses may be reservoirs for the zoonotic transmission of antimicrobial-resistant bacteria to humans and pose a major public health hazard. During the isolation of Salmonella from poultry and other foods, many of the presumptive typical Salmonella colonies on xylose lysine deoxycholate (XLD) agar were found to lack the invA gene, which is the specific target gene for Salmonella spp. Therefore, the current study aimed to estimate the prevalence and antimicrobial resistance profiles of extensively drug-resistant invA-negative non-Salmonella isolates recovered from native Egyptian chicken carcasses as presumptive Salmonella colonies on XLD agar. The non-Salmonella isolates were detected in 84% (126/150) of the examined native Egyptian chicken carcasses and classified into five genera, with prevalence rates of 64% (96/150), 14% (21/150), 6.7% (10/150), 3.3% (5/150), and 1.3% (2/150) for Proteus, Citrobacter, Shigella, Pseudomonas, and Edwardsiella, respectively. One hundred and ninety-five invA-negative, non-verified presumptive Salmonella isolates were recovered and classified at the species level into Proteus mirabilis (132/195; 67.7%), Proteus vulgaris (11/195; 5.6%), Citrobacter freundii (26/195; 13.3%), Shigella flexneri (8/195; 4.1%), Shigella sonnei (6/195; 3.1%), Shigella dysenteriae (3/195; 1.5%), Pseudomonas fluorescens (6/195; 3.1%), and Edwardsiella tarda (3/195; 1.5%). All (195/195; 100%) of these isolates showed resistance against cefaclor and fosfomycin. Additionally, these isolates showed high resistance rates of 98%, 92.8%, 89.7%, 89.2%, 89.2%, 86.7%, 80%, 78.5%, 74.4%, and 73.9% against cephalothin, azithromycin, vancomycin, nalidixic acid, tetracycline, sulfamethoxazole/trimethoprim, cefepime, gentamicin, cefotaxime, and ciprofloxacin, respectively. Interestingly, all (195/195; 100%) of the identified isolates were resistant to at least five antibiotics and exhibited an average MAR (multiple antibiotic resistance) index of 0.783. Furthermore, 73.9% of the examined isolates were classified as extensively drug-resistant, with an MAR index equal to 0.830. The high prevalence of extensively drug-resistant foodborne Proteus, Citrobacter, Shigella, Pseudomonas, and Edwardsiella isolated from native chicken carcasses poses a great hazard to public health and necessitates more monitoring and concern about the overuse and misuse of antibiotics in humans and animals. This study also recommends the strict implementation of GHP (good hygienic practices) and GMP (good manufacturing practices) in the chicken meat supply chain to protect consumer health.

Keywords: Proteus vulgaris; Proteus mirabilis; Shigella; chicken meat; multidrug-resistant.

Figure 1

(A). Typical presumptive Salmonella colonies on xylose lysine deoxycholate (XLD) agar (in pink, with or without a black center) that were taken and subjected to PCR for the verification of Salmonella from non-Salmonella species. (B). Representative agarose gel electrophoresis image from the PCR assay for the detection of the invA (244 bp) gene specific for Salmonella in the genome prepared from the Salmonella presumptive colonies. M: DNA marker (100-bp gene ladder). Lanes 1–13: invA-gene-negative, indicating non-Salmonella isolates that were selected and subjected to further analysis. C+: positive control. C−: negative control. Eight microliters of the PCR product was separated via electrophoresis on 1.5% agarose gel and visualized under UV light.

Figure 2

Prevalence of Proteus mirabilis and other Gram-negative non-Salmonella species in native Egyptian chicken carcasses tested (n = 150).

Figure 3

Frequency distribution of Proteus mirabilis and other species among the Gram-negative non-Salmonella isolates (n = 195) recovered from Egyptian chicken carcasses.