Antibiotic resistance and molecular characterization of the hydrogen sulfide-negative phenotype among diverse Salmonella serovars in China

Abstract

BackgroundAmong 2179 Salmonella isolates obtained during national surveillance for salmonellosis in China from 2005 to 2013, we identified 46 non-H2S-producing strains originating from different sources.MethodsThe isolates were characterized in terms of antibiotic resistance and genetic variability by pulsed-field gel electrophoresis and multilocus sequence typing. Mutation in the phs operon, which may account for the non-H2S-producing phenotype of the isolated Salmonella strains, was performed in this study.ResultsAmong isolated non-H2S-producing Salmonella strains, more than 50% were recovered from diarrhea patients, of which H2S-negative S. Gallinarum, S. Typhimurium, S. Choleraesuis and S. Paratyphi A isolates constituted 76%. H2S-negative isolates exhibited a high rate of resistance to ticarcillin, ampicillin, and tetracycline, and eight of them had the multidrug resistance phenotype. Most H2S-negative Salmonella isolates had similar pulsed-field gel electrophoresis profiles and the same sequence type as H2S-positive strains, indicating a close origin, but carried mutations in the phsA gene, which may account for the non-H2S-producing phenotype.ConclusionsOur data indicate that multiple H2S-negative strains have emerged and persist in China, emphasizing the necessity to implement efficient surveillance measures for controlling dissemination of these atypical Salmonella strains.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3209-3) contains supplementary material, which is available to authorized users.

Salmonella in Retail Food and Wild Birds in Singapore—Prevalence, Antimicrobial Resistance, and Sequence Types

“…Animals, besides human, can be reservoirs of S. Paratyphi B [39]. In addition, S. Paratyphi B, in particular ST42, has been found in food, feed, fertilizer, and reptiles [40,41]. While, not all variants of S. Paratyphi B are capable of causing enteric fever, S. Paratyphi B primarily causes gastroenteritis [42], similar to the non-typhoidal strains.…”

Prevalence of Salmonella Isolated in Cattle, Inva Gene Detection and Antimicrobial Susceptibility Patterns of Isolates

“…Presumptive Salmonella colonies were then transferred to tubes of Triple Sugar Iron (TSI) (Oxoid, Basingstoke,UK) agar using sterile loops and incubated at 37 o C for 18-24 hrs. Salmonella produced alkaline slant over acid with or without Hydrogen Sulphide (H 2 S) and gas, similar to some strains of S. Cholerasuis S. Gallinarum, S. Typhimurium, S. Choleraesuis and S. Paratyphi A which do not produce H 2 S (Xie et al, 2018). Some isolates did not produce the typical Salmonella reactions.…”

Isolation of Non-Hydrogen Sulfide-Producing Salmonella enterica Serovar Infantis from a Clinical Sample: the First Case in Korea

“…Production of hydrogen sulfide (H2S) is a unique property of Salmonella, and it is commonly detected to differentiate Salmonella species from other bacterial pathogens using biochemical test media such as triple sugar iron (TSI) agar. However, several non-H2S-producing Salmonella species have been isolated in various countries (mainly China) from poultry meat [3] or clinical samples such as stool or sacral wound (Table 1) [4][5][6][7][8][9][10]. Enzymes encoded by the phs, cysJIH, and asr operons are essential for H2S production.…”

“…Direct sequencing of the phs and cysJIH operons of the isolate was performed, and the sequences aligned to those of strain Salmonella enterica serovar Infantis FSIS1502916 (NZ_CP016408.1) using DNAman 6.0 (Lynnon, Quebec, Canada). The primers were as follows: cysJ1 forward 5´-CGGCATCGGACAGTTTACCT-3´ and reverse 5´-CTGGATGCTCAGGCGCTAAT-3´, cysJ2 forward 5´-GATTAGCGCCTGAGCATCCA-3´ and reverse 5´-CGTGTCGAT-GCTGACGTTGA-3´, cysJ3 forward 5´-TTCAACGTCAGCATCGA-CAC-3´ and reverse 5´-CTGCGTTTACTCACCCCAGT-3´, cysI1 forward 5´-CTCGCGGTATACCTTGCCTG-3´ and reverse 5´-CT-GCTGGAGATCGCGAAGAT-3´, cysI2 forward 5´-GCACGCTGGC-AATAATCAGG-3´ and reverse 5´-TGCATGCTGAAGCCTACGAA-3´, cysI3 forward 5´-CGATATCATTTTGCGGCGGG-3´ and reverse 5´-CGGTATGGACCTCGAATCGG-3´, cysH forward 5´-GCCGGAT-TTTTCATAGCAGCA-3´ and reverse 5´-CAGGCAAGGTATACCGC-GAG-3´, and previously reported primers for phs [10]. Unlike previous cases [10], no point mutation was found in the coding region of the phs operon, whereas a nucleotide change (C to T) at the first base pair in the 3´-untranslated region of phsC was observed.…”