The effect of distal locking mode on postoperative mechanical complications in intertrochanteric fractures: a retrospective cohort study of five hundred and seven patients.

PURPOSE: The optimal choice of distal locking modes remains a subject due to limited available data, and therefore, this study aims to investigate the relationship between distal locking mode and postoperative mechanical complications in an intertrochanteric fracture (ITF) population who underwent closed reduction and intramedullary fixation with a PFNA-II. METHODS: Patients aged 65 years or older who underwent surgery with PFNA-II fixation in a university teaching hospital between January 2020 and December 2021 were potentially eligible. Based on the distal locking mode, patients were classified into static, dynamic, and limited dynamic groups, among which the differences were tested using univariate analysis. Multivariate logistic regression was used to examine whether the distal locking mode was independently associated with the risk of postoperative one year mechanical complications, adjusting for covariates and potential confounders. Subgroup analyses were performed to evaluate the robustness of the findings. RESULT: Among 507 eligible patients, 33 (6.5%) developed postoperative mechanical complications. In the univariate analysis, sex (P = 0.007), fracture type (P = 0.020), LAT Parker ratio (P = 0.023), and lateral femoral (P = 0.003) wall showed that the differences were significant. Compared to the static group, the limited dynamic group and the dynamic group showed higher odds of postoperative mechanical complications (OR = 3.314, 95% CI: 1.215-9.041; and OR = 3.652, 95% CI: 1.451-9.191, respectively). These associations were robust across a series of analyses, including adjusting for confounders and subgroup analyses. CONCLUSION: Using a distal non-static locking mode significantly increases the risk of postoperative mechanical complications, and static locking could be a preferable option when treating an intertrochanteric fracture.

Comparison of outcomes after total hip arthroplasty between patients with osteonecrosis of the femoral head in Association Research Circulation Osseous stage III and stage IV: a five-year follow-up study.

BACKGROUND: No large cohort study has evaluated the surgical outcomes of THA between different stages of ONFH patients. This study aimed to compare the surgical outcomes of ONFH patients who underwent THA in ARCO stage III versus IV, in terms of operative parameters, one-year hip function assessments and postoperative at least five-year complications, to inform optimized management of ONFH. METHOD: From our prospectively collected database, 876 patients undergoing THA between October 2014 and April 2017 were analyzed and divided into ARCO stage III group (n = 383) and ARCO stage IV group(n = 493). Details of demographics, medical record information, adverse events and clinical scores of both groups were collected and compared. Proper univariate analysis was used for the analysis. RESULT: There were no statistically significant differences in baseline characteristics between the two groups. Compared to ARCO stage IV patients, ARCO stage III patients showed a shorter operative time (p < 0.01), less bleeding (p < 0.01), fewer one-year readmissions (p = 0.026) and complications (p = 0.040), and significantly higher HHS (p < 0.01) one year after THA. In addition, ARCO stage IV patients seem more likely to suffer prosthesis dislocation (p = 0.031). CONCLUSION: Although ARCO stage IV patients in the study cohorts appeared to suffer more one-year complications, no significant difference was observed at long-term follow-up. Enhanced clinical guidance on preventing early prosthesis dislocation may help improve the prognosis of final-stage ONFH patients.

The value of D-dimer to lymphocyte ratio in predicting clinical outcomes after percutaneous coronary intervention in ST-segment elevation myocardial infarction patients: A retrospective study.

BACKGROUND: D-dimer to lymphocyte ratio (DLR) is a novel composite metric. This study investigated the association between DLR and major adverse cardiovascular events (MACEs) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention. MATERIALS AND METHODS: This retrospective study included 683 STEMI cases treated between January 2018 and June 2021 at a single center. DLR was calculated for each patient. Receiver operating characteristic curves assessed the predictive value of in-hospital and long-term MACEs, with calculated AUC. Based on the optimal DLR cutoff value, the population was categorized into groups for clinical characteristic analysis. Multivariate logistic and COX regression analyses determined factors independently associated with MACEs. Kaplan-Meier estimation method and log-rank tests assessed event-free survival among different DLR groups. Spearman's test explored the correlation between DLR and Gensini score. RESULTS: DLR demonstrated an AUC of 0.792 for predicting in-hospital MACEs and 0.708 for long-term MACEs in patients with STEMI. Multivariate logistic regression analysis revealed that a high DLR (cutoff value, 0.47) independently increased the risk of MACEs during hospitalization in patients with STEMI (P = 0.003; odds ratio: 3.015; 95 % CI: 1.438-6.321). Multivariate COX regression showed that a high DLR (cutoff value, 0.34) independently predicted MACEs during long-term follow-up in patients with STEMI (P = 0.011; hazard ratio: 1.724; 95 % CI: 1.135-2.619). Furthermore, DLR exhibited a positive correlation with the Gensini score (P < 0.001). CONCLUSIONS: DLR is a valuable predictor for MACEs occurrence in patients with STEMI during hospitalization and long-term follow-up after PCI.

Risk Factors and Dynamic Nomogram Development for Surgical Site Infection Following Open Wedge High Tibial Osteotomy for Varus Knee Osteoarthritis: A Retrospective Cohort Study.

Background: As the worldwide population ages, the population receiving open wedge high tibial osteotomy (OWHTO) is growing, and surgical site infection (SSI) is a rare but fatal surgical complication. This study aimed to identify risk factors independently associated with SSI following OWHTO and develop a predictive nomogram. Methods: Clinical data of patients who received OWHTO and followed up for more than 12 months in our hospital were retrospectively reviewed. Multivariable logistic regression was performed to determine independent risk factors for SSI and to construct predictive nomograms. The study further illustrated the predictive performance of the model by using the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA). Results: A total of 1294 eligible patients were included in the study. Multivariate analysis revealed tobacco consumption (OR=3.44, p=0.010), osteotomy size ≥12 mm (OR=3.3, p=0.015), the use of allogeneic bone or artificial bone graft substitutes (allogeneic bone vs none, OR=4.08, p=0.037; artificial bone vs none, OR=5.16, p=0.047), Kellgren-Lawrence (K-L) grade IV (OR=2.5, p=0.046), systemic immune-inflammation index (SII) >423.62 (OR=6.2, p<0.001), high-sensitivity C-reactive protein (HCRP) >2.6 mg/L (OR=2.42, p=0.044), and a higher level of fasting blood glucose (FBG) (OR=1.32, p=0.022) were the independent predictors of SSI. The cutoff score of the model was 148, with a sensitivity of 76.0% and specificity of 81.0%. The concordance index (C-index) and Brier score of the nomogram were 0.856 and 0.017, and the corrected values after 1000 bootstrapping validations were 0.820 and 0.018, respectively. Furthermore, the ROC curve, calibration curve, and DCA exhibited excellent predictive accuracy and clinical applicability of the model. Conclusion: This study developed a dynamic nomogram based on seven predictors, which allowed surgeons to individualize risk stratification of patients and intervene promptly to reduce SSI rates.

One-year unplanned readmission after total hip arthroplasty in patients with osteonecrosis of the femoral head: rate, causes, and risk factors.

BACKGROUND: The primary objectives of this study were to focus on one - year unplanned readmissions after THA in ONFH patients and to investigate rates, causes, and independent risk factors. METHODS: Between October 2014 and April 2019, eligible patients undergoing THA were enrolled and divided into unplanned readmission within one year and no readmission in this study. All unplanned readmissions within 1 year of discharge were reviewed for causes and the rate of unplanned readmissions was calculated. Demographic information, ONFH characteristics, and treatment-related variables of both groups were compared and analysed. RESULTS: Finally, 41 out of 876 patients experienced unplanned readmission. The readmission rate was 1.83% in 30 days 2.63% in 90 days, and 4.68% in 1 year. Prosthesis dislocation was always the most common cause at all time points studied within a year. The final logistic regression model revealed that higher risks of unplanned readmission were associated with age > 60 years (P = 0.001), urban residence (P = 0.001), ARCO stage IV (P = 0.025), and smoking (P = 0.033). CONCLUSIONS: We recommend the introduction of a strict smoking cessation program prior to surgery and the development of comprehensive management strategies, especially for the elderly and end-stage ONFH patients, and pay more attention to preventing prosthesis dislocation in the early days after surgery.

Cronobacter spp. Isolated from Quick-Frozen Foods in China: Incidence, Genetic Characteristics, and Antibiotic Resistance.

Cronobacter spp. are emerging foodborne pathogens that cause severe diseases. However, information on Cronobacter contamination in quick-frozen foods in China is limited. Therefore, we studied the prevalence, molecular characterization, and antimicrobial susceptibility of Cronobacter in 576 quick-frozen food samples collected from 39 cities in China. Cronobacter spp. were found in 18.75% (108/576) of the samples, and the contamination degree of the total positive samples was 5.82 MPN/g. The contamination level of frozen flour product samples was high (44.34%). Among 154 isolates, 109 were C. sakazakii, and the main serotype was C. sakazakii O1 (44/154). Additionally, 11 serotypes existed among four species. Eighty-five sequence types (STs), including 22 novel ones, were assigned, indicating a relatively high genetic diversity of the Cronobacter in this food type. Pathogenic ST148, ST7, and ST1 were the main STs in this study. ST4, epidemiologically related to neonatal meningitis, was also identified. All strains were sensitive to cefepime, tobramycin, ciprofloxacin, and imipenem, in which the resistance to cephalothin was the highest (64.94%).Two isolates exhibited multidrug resistance to five and seven antimicrobial agents, respectively. In conclusion, these findings suggest that the comparatively high contamination level of Cronobacter spp. in quick-frozen foods is a potential risk warranting public attention.

Fatal Necrotizing Enterocolitis in Neonate Caused by Cronobacter sakazakii Sequence Type 64 Strain of CRISPR Sublineage b.

We report fatal neonatal necrotizing enterocolitis in China caused by Cronobacter sakazakii capsular profile K1:CA1, sequence type 64, and CRISPR type 197. Phylodynamic analyses indicated that the strain originated from the ancient, widespread, and antimicrobial drug-sensitive CRISPR sublineage b. Enhanced surveillance and pathogenesis research on this organism are required.

Occurrence, molecular characterization and antibiotic resistance of Cronobacter spp. isolated from wet rice and flour products in Guangdong, China.

This study explored the prevalence of Cronobacter spp. in wet rice and flour products from Guangdong province, China, the molecular characteristics and antimicrobial susceptibility profiles of the isolates were identified. Among 249 samples, 100 (40.16%) were positive for Cronobacter spp., including 77 wet rice and 23 wet flour products. Eleven serotypes were characterized among 136 isolates with C. sakazakii O2 (n = 32) predominating. Forty-nine MLST patterns were assigned, 15 of which were new. C. sakazakii ST4 (n = 17) was the dominant ST, which is previously reported to have caused three deaths; followed by C. malonaticus ST7 (n = 15), which is connected to adult infections. All strains presented susceptibility to ampicillin/sulbactam, imipenem, aztreonam and trimethoprim/sulfamethoxazole. The isolates showed maximum resistance to cephalothin, and the resistance and intermediate rates were 91.91% and 3.68%, each. Two strains, croM234A1 and croM283-1, displayed resistance to three antibiotics. High contamination level and predominant number of pathogenic STs of Cronobacter in wet rice and flour products implied a potential risk to public healthiness. This survey could provide comprehensive information for establishing more targeted control methods for Cronobacter spp.

Development and validation of a nomogram for predicting the risk of immediate postoperative deep vein thrombosis after open wedge high tibial osteotomy.

PURPOSE: This study aimed to identify independent risk factors for immediate postoperative deep vein thrombosis (DVT) in patients with open wedge high tibial osteotomy (OWHTO) and to develop and validate a predictive nomogram. METHODS: Patients who underwent OWHTO for knee osteoarthritis (KOA) from June 2017 to December 2021 were retrospectively analyzed. Baseline data and laboratory test results were collected, and the occurrence of DVT in the immediate postoperative period was regarded as the study outcome event. Multivariable logistic regression identified independent risk factors associated with a higher incidence of immediate postoperative DVT. The predictive nomogram was constructed based on the analysis results. The stability of the model was further assessed in this study using patients from January to September 2022 as an external validation set. RESULTS: 741 patients were enrolled in the study, of which 547 were used in the training cohort and the other 194 for the validation cohort. Multivariate analysis revealed a higher Kellgren-Lawrence (K-L) grade (III vs. I-II OR 3.09, 95% CI 0.93-10.23. IV vs. I-II OR 5.23, 95% CI 1.27-21.48.), platelet to hemoglobin ratio (PHR) > 2.25 (OR 6.10, 95% CI 2.43-15.33), Low levels of albumin (ALB) (OR 0.79, 95% CI 0.70-0.90), LDL-C > 3.40 (OR 3.06, 95% CI 1.22-7.65), D-dimer > 1.26 (OR 2.83, 95% CI 1.16-6.87) and BMI ≥ 28 (OR 2.57, 95% CI 1.02-6.50) were the independent risk factors of immediate postoperative DVT. The concordance index (C-index) and Brier score of the nomogram were 0.832 and 0.036 in the training set, and the corrected values after internal validation were 0.795 and 0.038, respectively. The receiver-operating characteristic (ROC) curve, the calibration curve, the Hosmer-Lemeshow test, and the decision curve analysis (DCA) performed well in both the training and validation cohorts. CONCLUSION: This study developed a personalized predictive nomogram with six predictors, which allows surgeons to stratify risk and recommended immediate ultrasound scans for patients with any of these factors. LEVEL OF EVIDENCE: III.

Association of preoperative nutritional status evaluated by the controlling nutritional status score with walking independence at 180 days postoperatively: a prospective cohort study in Chinese older patients with hip fracture.

BACKGROUND: Malnutrition is significantly associated with unfavorable outcomes, but there is little high-level evidence to elucidate the association of malnutrition with losing walking independence (LWI) after hip fracture surgery. This study aimed to assess the association between preoperative nutritional status evaluated by the Controlling Nutritional Status (CONUT) score and walking independence at 180 days postoperatively in Chinese older hip fracture patients. METHODS: This prospective cohort study included 1958 eligible cases from the SSIOS database. The restricted cubic spline was used to assess the dose-effect relationship between the CONUT score and the recovery of walking independence. Propensity score matching was performed to balance potential preoperative confounders, and multivariate logistic regression analysis was applied to assess the association between malnutrition and LWI with perioperative factors for further adjustment. Furthermore, inverse probability treatment weighting and sensitivity analyses were performed to test the robustness of the results and the Fine and Gray hazard model was applied to adjust the competing risk of death. Subgroup analyses were used to determine potential population heterogeneity. RESULTS: The authors found a negative relationship between the preoperative CONUT score and recovery of walking independence at 180 days postoperatively, and that moderate-to-severe malnutrition evaluated by the CONUT score was independently associated with a 1.42-fold (95% CI, 1.12-1.80; P =0.004) increased risk of LWI. The results were overall robust. And in the Fine and Gray hazard model, the result was still statistically significant despite the apparent decrease in the risk estimate from 1.42 to 1.21. Furthermore, significant heterogeneities were observed in the subgroups of age, BMI, American Society of Anesthesiologists score, Charlson's comorbidity index, and surgical delay ( P for interaction < 0.05). CONCLUSION: Preoperative malnutrition is a significant risk factor for LWI after hip fracture surgery, and nutrition screening on admission would generate potential health benefits.

Novel phage vB_CtuP_B1 for controlling Cronobacter malonaticus and Cronobacter turicensis in ready-to-eat lettuce and powered infant formula.

Cronobacter spp. are important foodborne pathogens that are a threat to people of all ages, but especially neonates and infants. Bacteriophages are biological agents that are potentially useful for the control of foodborne pathogens. However, there has been little research on the control of C. malonaticus and C. turicensis using bacteriophages. In the present study, a novel lytic phage vB_CtuP_B1 (hereafter referred to as B1)-which can simultaneously lyse C. malonaticus and C. turicensis- was isolated from river water in Guangzhou, China, and was used in the control of Cronobacter contaminated food. The phage has a short tail, and has been identified as a new species of Kayfunavirus based on genomic and phylogenetic analyses. One-step growth and stability assays revealed that phage B1 has a very short latent period (<5 min) and a large burst size (4006 pfu/cell), and is highly stable between 25 and 60 °C and between pH 5 and 11. Its genome encodes two lytic proteins, but does not contain any genes responsible for antibiotic resistance and virulence factors. In broth, the phage B1 completely inhibited the growth of C. malonaticus cro2475W and C. turicensis cro1541A1-1 for up to 6 h. On lettuce, phage B1 reduced the viable count of C. turicensis cro1541A1-1 to below the detection limit for bacteria on lettuce (<10 cfu/mL) after 6 h at 4 °C and 2 h at 25 °C, and also significantly reduced the viable count of C. malonaticus cro2475W at those temperatures. In powdered infant formula, the viable counts of both the phage-treated bacterial hosts were significantly reduced after 2 h of storage at 4 °C or 37 °C. Furthermore, phage B1 reduced the viable count of C. turicensis cro1541A1-1 to below the detection limit (<10 cfu/mL) from 4 h to 24 h at 37 °C. It significantly inhibited the growth of C. turicensis cro1541A1-1 than that of C. malonaticus cro2475W (P < 0.05). In conclusion, phage B1 with high stability and strong lytic ability is potentially useful for controlling C. malonaticus and C. turicensis.

Isolation and characterization of new phage vB_CtuP_A24 and application to control Cronobacter spp. in infant milk formula and lettuce.

Cronobacter spp. are opportunistic pathogenic bacteria that cause severe diseases in neonates and infants. Bacteriophages are novel antibacterial agents with a potential to control this pathogen. In the current study, a novel lytic Cronobacter phage, vB_CtuP_A24, was isolated from a river in Guangzhou, China. The phage was characterized by a short, non-contractile tail and a long head and identified as a new member of the family Podoviridae. Complete genome sequence analysis of this phage indicated that its genome contained 75,106 bp of DNA, an average GC content of 44.05%, and 108 predicted open reading frames (ORFs). The annotated ORFs were associated with phage structure, packaging, host lysis, DNA manipulation, transcription, and additional functions. Genes responsible for antibiotic resistance, virulence, and toxic effects were not present. Cronobacter phage vB_CtuP_A24 is a novel lytic phage that can lyse five Cronobacter spp. It was stable over a wide range of temperatures (25-60 °C) and pH values (pH 4-11) and displayed a short latent period (approximately 10 min) and a large burst size (500 plaque-forming units (PFUs)/cell). In Luria-Bertani (LB) broth, phage A24 effectively inhibited the growth of C. dublinensis cro280B, C. sakazakii 465G, and C. malonaticus cro695W up to 9, 10, and 12 h, respectively, while in infant milk formulas, it inhibited two strains, C. sakazakii 465G and C. malonaticus cro695W, up to 24 h at 37 °C, with maximum reduction levels of approximately 5.12 ± 3.95 and 7.38 ± 3.03 log10 colony-forming unit (CFU)/mL, respectively. In lettuce, the reduction of all three strains was highly significant at 25 °C. However, the growth of C. dublinensis cro280B and C. sakazakii 465G were not significantly inhibited at 4 °C. In conclusion, Cronobacter spp. phage vB_CtuP_A24, which has lytic ability against five Cronobacter species, stability under different environments, and shows potential as a promising biocontrol agent against Cronobacter spp. in food production.

Cronobacter spp. isolated from aquatic products in China: Incidence, antibiotic resistance, molecular characteristic and CRISPR diversity.

Cronobacter species (Cronobacter spp.) are important foodborne pathogens that can infect and cause serious life-threatening diseases in infants and immunocompromised elderly. This study aimed to acquire data on Cronobacter spp. contamination of aquatic products in China from 2011 to 2016. In total, 800 aquatic products were tested, and the overall contamination rate for Cronobacter spp. was 3.9% (31/800). The average contamination level of the positive samples was 2.05 MPN/g. Four species and nine serotypes were identified among 33 isolates, of which the C. sakazakii serogroup O1 (n = 9) was the primary serotype. The majority of Cronobacter spp. strains harbored highest resistance against cephalothin (84.8%), followed by tetracycline (6.1%), trimethoprim/sulfameth-oxazole (3.0%) and chloramphenicol (3.0%). Two isolates were resistant to three antibiotics. In total, 26 sequence types and 33 CRISPR types (including 6 new STs and 26 new CTs) were identified, which indicates the extremely high diversity of Cronobacter spp. in aquatic products. Pathogenic C. sakazakii ST4, ST1, and C. malonaticus ST7 were also observed. Overall, this large-scale study revealed the relatively low prevalence and high genetic diversity of Cronobacter spp. in aquatic products in China, and the findings provide valuable information that can guide the establishment of effective measures for the control and precaution of Cronobacter spp. in aquatic products during production processes.

Corrigendum: Cronobacter sakazakii, Cronobacter malonaticus, and Cronobacter dublinensis Genotyping Based on CRISPR Locus Diversity.

[This corrects the article DOI: 10.3389/fmicb.2019.01989.].

Prevalence, genetic analysis and CRISPR typing of Cronobacter spp. isolated from meat and meat products in China.

Cronobacter spp. are important foodborne pathogens that infections occur in all age groups, especially cause serious life-threatening diseases in infants. This study aimed to acquire data on Cronobacter spp. contamination of meat and meat products (n = 588) in China during 2011 to 2016, and investigated the use of CRISPR typing technology as an approach for characterizing the genetics of Cronobacter spp. The overall contamination rate for Cronobacter spp. was determined to be 9.18% (54/588). Of the positive samples, 90.74% (49/54) had <10 MPN/g, with duck samples had a relatively high contamination rate (15.69%, 8/51) and highest contamination level (28.90 MPN/g). Four species and nine serotypes were identified among 69 isolates, of which C. sakazakii was the major species (n = 50) and C. sakazakii serogroup O1 and O2 (n = 17) were the primary serotypes. The majority of Cronobacter spp. strains were found to be susceptible to most antibiotics except exhibited high resistance to cephalothin (76.81%, 53/69), and total two multi-drug resistant C. sakazakii strains were isolated from duck. The genetic diversity of Cronobacter spp. was remarkably high, as evidenced by the identification of 40 sequence types (STs) and 60 CRISPR types (CTs). C. sakazakii ST64 (n = 7) was the predominant genotype and was further divided into two sub-lineages based on CRISPR diversity, showing different antibiotic resistance profile. These results demonstrate that CRISPR typing results have a good correspondence with bacterial phenotypes, and it will be a tremendously useful approach for elucidating inter-subtyping during molecular epidemiological investigations while interpreting the divergent evolution of Cronobacter. The presence of Cronobacter spp. in meat and meat product is a potential threat to human public health.

Cronobacter sakazakii, Cronobacter malonaticus, and Cronobacter dublinensis Genotyping Based on CRISPR Locus Diversity.

Cronobacter strains harboring CRISPR-Cas systems are important foodborne pathogens that cause serious neonatal infections. CRISPR typing is a new molecular subtyping method to track the sources of pathogenic bacterial outbreaks and shows a promise in typing Cronobacter, however, this molecular typing procedure using routine PCR method has not been established. Therefore, the purpose of this study was to establish such methodology, 257 isolates of Cronobacter sakazakii, C. malonaticus, and C. dublinensis were used to verify the feasibility of the method. Results showed that 161 C. sakazakii strains could be divided into 129 CRISPR types (CTs), among which CT15 (n = 7) was the most prevalent CT followed by CT6 (n = 4). Further, 65 C. malonaticus strains were divided into 42 CTs and CT23 (n = 8) was the most prevalent followed by CT2, CT3, and CT13 (n = 4). Finally, 31 C. dublinensis strains belonged to 31 CTs. There was also a relationship among CT, sequence type (ST), food types, and serotype. Compared to multi-locus sequence typing (MLST), this new molecular method has greater power to distinguish similar strains and had better accordance with whole genome sequence typing (WGST). More importantly, some lineages were found to harbor conserved ancestral spacers ahead of their divergent specific spacer sequences; this can be exploited to infer the divergent evolution of Cronobacter and provide phylogenetic information reflecting common origins. Compared to WGST, CRISPR typing method is simpler and more affordable, it could be used to identify sources of Cronobacter food-borne outbreaks, from clinical cases to food sources and the production sites.

Prevalence, Antibiotic Susceptibility, and Molecular Characterization of Cronobacter spp. Isolated From Edible Mushrooms in China.

Cronobacter spp. are foodborne pathogens that can infect and cause life-threatening diseases in all age groups, particularly in infants and immunocompromised elderly. This study aimed to investigate the prevalence, antibiotic susceptibility, and molecular characteristics of Cronobacter spp. isolates in edible mushrooms collected from 44 cities in China. In total, 668 edible mushrooms were collected from traditional retail markets and supermarkets and were analyzed by quantitative methods, PCR-based serotyping, multilocus sequence typing (MLST), and antibiotic susceptibility testing. Among the 668 samples tested, 89 (13.32%) were positive for Cronobacter spp., and the contamination levels exceeded the 110 most probable number (MPN)/g in 13.48% (12/89) of the samples. Flammulina velutipes samples had the highest contamination rate of 17.54% (37/211), whereas Hypsizygus marmoreus samples had the lowest contamination rate of 3.28% (2/61). Ten serotypes were identified among 115 isolates, of which the C. sakazakii serogroup O1 (n = 32) was the primary serotype. MLST indicated that there was quite high genetic diversity in Cronobacter spp. and 72 sequence types were identified, 17 of which were new. Notably, C. sakazakii ST148 (n = 10) was the most prevalent, followed by C. malonaticus ST7 (n = 5). Antibiotic susceptibility testing revealed that the majority of Cronobacter spp. strains were susceptible to the 16 antibiotics tested. However, a portion of isolates exhibited relatively high resistance to cephalothin, with resistance and intermediate rates of 93.91 and 6.09%, respectively. One isolate (cro300A) was multidrug-resistant, with resistance to five antibiotics. Overall, this large-scale study revealed the relatively high prevalence and high genetic diversity of Cronobacter spp. on edible mushrooms in China, indicating a potential public health concern. To our knowledge, this is the first large-scale and systematic study on the prevalence of Cronobacter spp. on edible mushrooms in China, and the findings can provide valuable information that can guide the establishment of effective measures for the control and precaution of Cronobacter spp on edible mushrooms during production processes.

Complete genome analysis of a novel phage GW1 lysing Cronobacter.

A newly identified lytic Cronobacter phage, GW1, was isolated from the Pearl River of Guangzhou, China. GW1 had a double-stranded DNA genome of 39,695 nucleotides with an average GC content of 53.18 %. Among the 49 open reading frames (ORFs) identified, genes for rRNA, tRNA, antibiotic resistance, and virulence factors were not found in the phage genome. The morphology, genomic features, and phylogenetic position of GW1 revealed that it represents a new species in the genus T7virus. This novel lytic Cronobacter phage may provide an alternative for phage therapy and biocontrol against Cronobacter.

Novel Multidrug-Resistant Cronobacter sakazakii Causing Meningitis in Neonate, China, 2015.

We report a case of meningitis in a neonate in China, which was caused by a novel multidrug-resistant Cronobacter sakazakii strain, sequence type 256, capsular profile K1:CA1. We identified genetic factors associated with bacterial pathogenicity and antimicrobial drug resistance in the genome and plasmids. Enhanced surveillance of this organism is warranted.

Prevalence and Molecular and Antimicrobial Characteristics of Cronobacter spp. Isolated From Raw Vegetables in China.

Cronobacter spp. is a foodborne pathogen that causes life-threatening and invasive diseases, such as necrotizing enterocolitis, meningitis, and sepsis. In this study, we aimed to investigate the prevalence, molecular characteristics and antimicrobial resistance of Cronobacter spp. in raw vegetables marketed in China. Based on dietary habits in China, 403 raw vegetables that could be eaten without additional cooking were collected. Of the 403 samples tested, 122 (30.27%) were positive for Cronobacter spp., and the contamination levels exceeded 110 most probable number (MPN)/g for 16.39% (20/122) of the samples. Coriander samples had the highest contamination rate of 52.81%, and the MPN values of 19.15% of positive coriander samples exceeded 100 MPN/g. Eleven serotypes were identified among 171 isolates, with Cronobacter sakazakii serogroup O1 (41 isolates) being the dominant serotype. Molecular characterization indicated that there was quite high genetic diversity in Cronobacter spp., and multilocus sequence typing analyses yielded 106 sequence types (STs), 55 of which were newly identified. Notably, the most prevalent ST (eight isolates) was C. malonaticus ST60, which appeared in a recent clinical infectious disease study in China. Five C. sakazakii ST4, seven C. malonaticus ST7, and three C. sakazakii ST8 confirmed as pathogenic STs in other countries were also detected in this study. Furthermore, all isolates were susceptible to amikacin, amoxicillin-clavulanic, cefepime, ciprofloxacin, and imipenem, but some isolates exhibited a high ratio of resistance to cephalothin (59.65%). In this study, the high contamination rate and the detection of pathogenic and new STs in raw vegetables indicated potential hazards to customers. To the best of our knowledge, this is the first report to provide valuable information on the contamination status of Cronobacter spp. in vegetables that can be eaten raw in China.