Antibiotic Susceptibility and Molecular Screening of Class I Integron in Salmonella Isolates Recovered from Retail Raw Chicken Carcasses in China

Abstract

Salmonella is one of the leading causes for foodborne diseases. Foods, particularly those of animal origin, act as an important role for Salmonella transmission. In this study, the antibiotic susceptibility of 743 Salmonella isolates recovered from retail raw chicken carcasses in eight provinces was tested, and the isolates were also screened for the presence of class I integron and drug-resistant gene cassettes. One hundred thirteen (15.21%) isolates were harboring class I integron. A higher percentage of integron-positive Salmonella isolates were found in retail chicken in Sichuan Province (29.33%), followed by Beijing (22.14%), Shaanxi (19.15%), Guangxi (14.13%), Henan (12.50%), Shanghai (7.25%), Fujian (8.22%), and Guangdong (6.25%) Provinces. The respective prevalence of class I integron in Salmonella isolates recovered from retail chickens in large, free, and small markets was 16.31%, 14.04%, and 15.27%. Moreover, 20.13%, 14.02%, and 13.74% of Salmonella isolates recovered from retail chickens stored in frozen, chilled, and ambient conditions, respectively, were positive for class I integron. Subsequent sequencing of class I integron revealed the presence of 10 gene cassettes harboring resistance genes (dfrA17-aadA5, dfrA17-aadA5, dfrA1-aadA1, dfrA12-aadA2, dfrA17-aadA5-aadA4, dfrA1-aadA1-aadA2, dfrA1, dfrA5, aadA2, aacA4-catB8-aadA1-dfrA1-(aac6-II)-(bla-8), bla-bla). The most prevalent gene cassette was dfrA17-aadA5 (59.62%). Class I integron-positive isolates were significantly more resistant to multiple antibiotics, and they commonly exhibited corresponding antibiotic resistance profiles to the antibiotic resistance gene cassettes harbored in their class I integron. The results indicated that class I integron with different antibiotic resistance gene cassettes that were prevalent in Salmonella isolates differed from provinces, marketplaces, and chicken storage conditions.

Molecular Detection of Multidrug Resistant Salmonella Species Isolated from Broiler Farm in Bangladesh

“…Salmonella carrying class one integron int1 were found positive for multiple resistance genes. In this study, 20% isolates were found positive for the presence of the int1 gene, revealing the molecular basis of observed multidrug resistance [45]. These factors may facilitate the emergence of MDR pathogens.…”

“…These factors may facilitate the emergence of MDR pathogens. In many cases, resistance patterns are observed against those antimicrobials that are frequently used in veterinary practices [45,46].…”

Transmissible ST3-IncHI2 Plasmids Are Predominant Carriers of Diverse Complex IS26-Class 1 Integron Arrangements in Multidrug-Resistant Salmonella

“…Two such cassette arrays were embedded in simple integrons consisting of dfrA12 - orfF-aadA2 (1.9 kb, n = 4, Figure 3 I) and dfrA17-aadA5 (1.6 kb, n = 4, Figure 3 III), while the other two were embedded in complex integrons carrying the IS 26 element consisting of dfrA17-aadA5 -IS 26 (2.5 kb, n = 1, Figure 3 IV) and dfrA12-orfF- Δ aadA2 -IS 26 -Δ Tn3-orf (4 kb, n = 7, Figure 3 II). Array I and III in Figure 3 were popularly distributed in Salmonella (Li R. et al, 2013 ; Pérez-Moreno et al, 2013 ; Meng et al, 2017 ). Compared to Array I, aadA2 gene in Array II was truncated at the 578-bp from the 5′ CS by IS 26 , along with the insertion of a Δ Tn3-orf fragment and partial deletion of the qacE Δ 1 gene.…”

Horizontal Dissemination of Antimicrobial Resistance Determinants in Multiple Salmonella Serotypes following Isolation from the Commercial Swine Operation Environment after Manure Application

“…The integrons are able to locate on either a chromosome or a mobile genetic element such as a plasmid (60). Several studies have stated that the integrons harboring aadA or a variant of aadA genes are common among Salmonella species (10,(61)(62)(63). The variable parts of integrons might be composed of variants of aad, dfr, or bla genes that contribute to aminoglycoside, sulfonamide, and cephalosporin resistance, respectively (10,61).…”

“…Several studies have stated that the integrons harboring aadA or a variant of aadA genes are common among Salmonella species (10,(61)(62)(63). The variable parts of integrons might be composed of variants of aad, dfr, or bla genes that contribute to aminoglycoside, sulfonamide, and cephalosporin resistance, respectively (10,61). S. enterica serotype Worthington detected in our study is commonly found in poultry, poultry products, and the environment in several parts of the world and harbors integrons either on the chromosome or plasmids (62,(64)(65)(66).…”