Serovars and antimicrobial resistance of non-typhoidal Salmonella from human patients in Shanghai, China, 2006–2010

Abstract

We conducted a retrospective study on non-typhoidal Salmonella isolates from patients with diarrhoea in Shanghai, China, 2006-2010. A total of 1484 isolates of 70 Salmonella serovars were recovered from about 18 000 stool specimens. Serovars Enteritidis and Typhimurium were the most prevalent with isolation rates of 27.6% and 25.5%, respectively. The majority (1151, 77.6%) of the isolates were resistant to at least one antimicrobial, and 598 (40.3%) to more than three antimicrobials. Approximately half (50.9%) of the isolates were resistant to nalidixic acid and other resistance rates were sulfisoxazole (47.9%), streptomycin (37.6%), ampicillin (31.3%) and tetracycline (30.5%). Co-resistance to fluoroquinolones and the third- and fourth-generation cephalosporins was also identified.

Antimicrobial Susceptibility and Molecular Typing ofSalmonellaAgona Isolated from Humans and Other Sources

“…Resistance to sulfonamides was very common among nontyphoidal Salmonella isolated in China. For example, sulfonamides resistance was found in 45.7% of Salmonella isolated from domestic animals in Eastern China (Pan et al, 2010), while there was 47.9% resistance to Salmonella from human patients in Shanghai (Zhang et al, 2014). A relatively high level of resistance to SUL in our study (28.4%) was consistent with data from these studies.…”

“…In addition, 7.37% of Salmonella Agona were resistant to two or more antimicrobials in Shanghai in the present study, whereas a much larger proportion (57%) were resistant in the United States (Douris et al, 2008). Of the serotypes identified in the previous study in Shanghai, 40.3% of clinical nontyphoidal Salmonella were resistant to three or more drugs, and these were predominantly the serotypes Enteritidis (34.4%) and Typhimurium (33.6%) (Zhang et al, 2014). However, only four multidrug-resistant (three or more) isolates were identified in our study, indicating a significantly lower level of drug resistance compared with these two dominating serotypes in Shanghai.…”

“…Historically, Salmonella Enteritidis and Salmonella Typhimurium have been the most important cause of nontyphoidal salmonellosis, although other serotypes have been reported to be more prevalent in certain regions (Herikstad et al, 2002;Galanis et al, 2006;Ran et al, 2011). Salmonella Agona has ranked among the five most common serotypes of clinical nontyphoidal Salmonella in Shanghai (Zhang et al, 2014). This study examined Salmonella Agona isolates from humans, animals, food of animal origins and the environment to assess the significance of Salmonella Agona as a foodborne pathogen in Shanghai, China.…”

“…From 1997 to 2009, the Salmonella Surveillance Annual Summary of the United States Centers for Disease Control and Prevention reported Salmonella Agona as one of the 20 most frequently identified serotypes from both human and nonhuman sources (CDC, 2011). Currently, Salmonella Agona has been among 10 most common serotypes of nontyphoidal Salmonella isolated from diarrheal patients in China (Ran et al, 2011), and has ranked fifth in Shanghai (Zhang et al, 2014). However, there are limited data on the antimicrobial resistance and molecular epidemiological characteristics of Salmonella Agona in China.…”

Serotypes and antimicrobial susceptibility of Salmonella spp. isolated from farm animals in China

“…For example, amikacin had showed low levels of resistance (0.67%); this may be due to cross-resistance among aztreonam, ciprofloxacin, and β-lactams (Livermore, 2002). Co-resistance to fluoroquinolones and third- and fourth-generation cephalosporins has also been identified in Salmonella isolated from humans (Zhang et al, 2014). Considering these results, the prudent use of antibacterial agents should be strongly recommended in clinical, veterinary, and agricultural settings in order to preserve antibiotic activity and avoid the development of cross-resistance.…”