Introduction Highly fluoroquinolone-resistant Salmonella enterica serovar Kentucky(S.Kentucky)of sequence type(ST)198 has emerged as a global multidrug-resistant(MDR)clone,posing a threat to public health.Methods Whole genome sequencing and antibiotic susceptibility testing was used to characterize the population structure and evolutionary history of 54 S.Kentucky isolates recovered from food and human clinical cases in Beijing from 2016 to 2023.Results All 54 S.Kentucky ST198 isolates exhibited resistance to quinolones,carrying point mutations in the quinolone resistance-determining regions(gyrA_S83F and parC_S80I).Resistance to other antibiotics(folate pathway inhibitors,cephems,aminoglycosides,phenicols,rifamycin,fosfomycin,macrolides,and tetracyclines),mediated by the sul1,sul2,dfrA14,blaCTX-M,blaTEM-1B,aac(3)-Id,aadA2,aadA7,aph(3')-I,aph(3'')-Ib,rmtB,floR,arr-2,fosA,mph(A),and tet(A)genes,was also observed in different combinations.The Beijing S.Kentucky ST198 evolutionary tree was divided into clades 198.2-1 and 198.2-2,which were further differentiated into three subclades:198.2-2A,198.2-2B,and 198.2-2C.Compared with the extended-spectrumβ-lactamase-encoding gene blaCTX-M-14b in 198.2-1,the co-existence of blaCTX-M-55 and blaTEM-1B,as well as chromosomally located qnrS1,was detected in most 198.2-2 isolates,which showed more complex MDR phenotypes.S.Kentucky ST198 outbreak isolates derived from two predominant clonal sources:198.2-1 with cgST236434 and 198.2-2A with cgST296405.Conclusions The S.Kentucky population in Beijing is genetically diverse,consisting of multiple co-circulating lineages that have persisted since 2016.Strengthening surveillance of food and humans will aid in implementing measures to prevent and control the spread of AMR.
Mei QuYing HuangBing LyuXin ZhangYi TianZhaomin FengZhiyong GaoDaitao Zhang
BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.
Background: Donated blood contaminated with S. Typhi can cause post-transfusion sepsis. This study aimed to determine the correlation between some risk factors of typhoid fever and seroprevalence of antibodies against S. Typhi among blood donors. Methodology: Following informed consent, socio-demographic and information on risk factors of typhoid infection was obtained using pre-structured questionnaires from 400 apparently healthy blood donors at the Tema General Hospital. Blood was also collected for serology and cultured for identification of pathogens by standard bacteriological method. Results: Blood culture did not reveal any S. Typhi isolate out of the tested 400 (348 males and 52 females) samples from apparently healthy blood donors. However, IgM and IgG antibody seroprevalence of 9.3% and 3.5% were detected. Age group of 17 - 24 years was the highest risk group, persons with a history of typhoid infection, and sources of drinking water were major risk factors for typhoid infection. It was also observed that prevalence of IgM was highest among new donors (62.2%), but lower in donors with a history of 1 to 3 blood donations (32.4%) and least among regular donors (>3 donations (5.4%)). In addition, typhoid prevention awareness and typhoid knowledge (knowledge about typhoid transmission) among the donors were poor (4.3% and 5.9% respectively). Conclusions: This study has shown an overall seroprevalence of 9% and 3.5% for IgM and IgG antibodies respectively among blood donors in the Tema area in Ghana. We advocate for the mandatory screening of donor units intended for transfusion for S. Typhi. Furthermore, there is an urgent need for the health education of all persons in Ghana on preventive measures and the spread of S. Typhi.
