Prevalence, serotype, and antimicrobial resistance profiles of children infected with Salmonella in Guangzhou, southern China, 2016-2021.

Purpose: Salmonella infection is a key global public health concern and has lead to an increased economic burden on society. We investigated the epidemiological characteristics and antimicrobial resistance profiles of clinically isolated Salmonella strains in Guangzhou Women and Children's Medical Center. Patients and methods: This was a retrospective study of 1,338 Salmonella strains collected from children in Guangzhou Women and Children's Medical Center during 2016 to 2021. Results: The results revealed that 1,338 cases of Salmonella were mainly isolated from feces and blood samples. The age distribution was dominated by infants under 3 years old. The seasonal distribution was high in summer and autumn. 48 serotypes were detected, and S. typhimurium (78.7%) was the predominant serogroup. The results of antimicrobial susceptibility showed that the highest resistance was observed in ampicillin (84.5%), while lower resistance was observed in piperacillin/tazobactam, cefoperazone/sulbactam and ciprofloxacin. The antimicrobial resistance rate of fecal isolates was higher than that of blood isolates. The five-year average detection rate of multi-drug resistant Salmonella was 8.5% (114/1338) and the MDR rate of S. typhimurium was the lowest (6.9%; 73/1053). Conclusion: We concluded that antibacterial treatment should be carefully selected according to serotype and antimicrobial sensitivity results in children. Antimicrobial resistance monitoring for multi-drug resistant Salmonella is still required.

Molecular Characterization and Epidemiology of Carbapenem-Resistant Enterobacteriaceae Isolated from Pediatric Patients in Guangzhou, Southern China.

Background: Carbapenem-resistant Enterobacteriaceae (CRE) are spreading worldwide, posing a serious public health concern. However, the data on CRE strains that cause infections in children in Guangzhou remain limited. Therefore, this study aimed to investigate the epidemiology of CRE, drug resistance, and resistance mechanisms in children in Guangzhou, Southern China. Methods: In total, 54 nonrepetitive CRE strains were collected in pediatric patients at three centers in Guangzhou, Southern China, from January 2016 to August 2018. CRE isolates were used for further studies on antimicrobial susceptibility, the modified Hodge test (MHT), the modified carbapenem inactivation method (mCIM), and drug resistance genes. Multilocus sequence typing (MLST) was used to elucidate the molecular epidemiology of K. pneumoniae. Results: The isolated CRE strains include 34 K. pneumoniae (63.0%), 10 E. coli (18.5%), 4 Enterobacter cloacae (7.4%), and 6 Proteus mirabilis (11.1%) strains. The strains were isolated mainly from the blood (31.5%, n = 17), sputum (31.5%, n = 17), and urine (16.7%, n = 9). All CRE isolates were highly resistant to the third- or fourth-generation cephalosporins, carbapenems, and ß-lactam + ß-lactamase inhibitors (94.4%-96.3%). In addition, the resistance rates to amikacin, ciprofloxacin, levofloxacin, tigecycline, and colistin were 5.6%, 14.8%, 16.7%, 9.3%, and 0%, respectively. Carbapenemase was detected in 35 (64.8%) of the CRE isolates. The most dominant carbapenemase gene was bla NDM (n = 17, 48.6%), followed by bla IMP (n = 13, 37.1%) and bla OXA-23 (n = 4, 11.4%). Other carbapenemase genes (bla KPC, bla sim, bla Aim, bla GES, bla Gim, bla OXA-2 , and bla OXA-48 ) and the mcr-1 gene were not detected. MLST analysis showed high diversity among the K. pneumoniae, and ST45 (11.7%, 4/34) was the dominant sequence type. Conclusion: This study revealed bla NDM was the most dominant carbapenemase gene in children in Guangzhou. Infection control measures need to be taken for the prevention and treatment of CRE infections.

Diagnostic Value of IGFBP-2 in Predicting Preeclampsia before 20 Weeks of Pregnancy: A Prospective Nested Case-Control Study.

Purpose: To identify novel biomarker insulin-like growth factor binding protein-2 (IGFBP-2) associated with preeclampsia (PE) before 20 weeks of gestation and to explore the predictive value of plasma IGFBP-2 in PE. Methods: A prospective nested case-control investigation involving 122 PE patients and 122 normal controls (NC) that were matched 1 : 1 in terms of age and week of pregnancy was carried out in Guangzhou Women and Children's Medical Center (Guangzhou, China, 2018030306) from April 2016 to December 2019. At 8 to 20 weeks, blood samples from the mother were taken. To calculate the correlations, univariate conditional logistic regression was employed. Results: Herein, 12 clinical indices were significantly different between the PE and NC groups (uric acid (UA), cystatin C (Cys C), aspartate aminotransferase (AST), glutamyl transpeptidase (γ-GT), total bilirubin (TB), prothrombin time (PT), red blood cell (RBC), hematocrit (HCT), red cell distribution width (RDW), platelets (PLT), mean platelet volume (MPV), and thrombocytocrit (PCT)). Compared with the NC group (36.79 ± 19.91 pg/mL), the expression level of IGFBP2 in the PE group (19.76 ± 19.40 pg/mL) before 20 weeks of pregnancy was significantly decreased (P < 0.01). Two high-risk factors were found to be significantly associated with PE independently of confounders: anemia 4.35 (2.20-8.45) (P < 0.01) and cesarean section history 8.25 (2.67-26.67) (P < 0.01). As a result of the univariate logistic regression analysis, the following three variables were included in the final logistic regression model.: Y = -18.841 - 0.085 × (IGFBP-2) + 0.630 × (RDW) + 0.165 × (AST) + 0.863 × (MPV). In comparison to IGFBP-2 alone as an independent predictor of PE (AUC = 0.897, 95% CI 0.830-0.964), the model's discriminatory power was considerably higher (AUC = 0.953, 95% CI 0.911-0.995). Conclusion: Plasma IGFBP-2 before 20 weeks of pregnancy combined with high-risk factors and routine blood indexes has a high early predictive value for PE.

Incidence, Bacterial Profiles, And Antimicrobial Resistance Of Culture-Proven Neonatal Sepsis In South China.

BACKGROUND: Neonatal sepsis (NS) is one of the leading causes of infant morbidity and mortality, but little is known about pathogen incidence and distribution in China. METHODS: In this retrospective study (January 2012 to December 2016), culture-proven cases aged less than 28 days with diagnosed NS in the Guangzhou Women and Children's Medical Center, South China, were analyzed for pathogen incidence and antimicrobial resistance. RESULTS: A total of 620 isolates were identified from 597 NS cases. Gram-negative bacteria (n=371, 59.8%) dominated over Gram-positive bacteria (n=218, 35.2%) and fungi (n=30, 4.8%). Klebsiella pneumoniae (21.9%), Escherichia coli (21.9%), group B Streptococcus (GBS, 13.2%), and Staphylococcus aureus (6.8%) were the four most predominant pathogens. In early-onset sepsis (EOS), GBS (30.0%) and E. coli (20.0%) were dominant, whereas in late-onset sepsis (LOS), K. pneumoniae (25.6%) and E. coli (22.4%) were dominant. E. coli (25.2%) and GBS (17.7%) were the most frequently isolated from term patients, whereas K. pneumoniae was the most frequently isolated from preterm patients (34.9%). Of the infected infants, 9.5% died from sepsis, most commonly by E. coli infection (16.2%). Among 91,215 live births (LBs) delivered in the study hospital (2012-2016), 252 infants developed sepsis infection (2.76 per 1000 LBs, 95% CI 2.4-3.1), including EOS (0.78 per 1000 LBs) and LOS (2.13 per 1000 LBs). All GBS isolates were susceptible to ß-lactam antibiotics, and S. aureus, including methicillin-resistant isolates, were susceptible to vancomycin. An extended-spectrum ß-lactamase producer was identified in 37.3% of E. coli and 50.4% of K. pneumoniae. CONCLUSION: K. pneumoniae was the most frequent pathogen in culture-proven NS in South China, primarily associated with LOS in preterm, whereas GBS was the dominant pathogen in EOS. E. coli was common in both episodes with the highest mortality.

An increasing trend of neonatal invasive multidrug-resistant group B streptococcus infections in southern China, 2011-2017.

BACKGROUND: A multidrug-resistant (MDR) RR2 gene cluster was identified by whole-genome sequencing in several highly virulent (ST-17) Group B streptococcus (GBS) isolates, which caused neonatal invasive infections in southern China in 2016. Tracing the transmission and distribution of MDR isolates in this area is important for the effective management of future infections. The aim of this study was to obtain longitudinal data of MDR isolates to monitor epidemiological trends of general common isolates in southern China, and provide evidence for future characterization of antimicrobial resistance mechanisms. METHODS: Clinical information and antimicrobial susceptibility of GBS isolates were acquired from electronic information management system databases of the hospital under study between January 2011 and December 2017. To confirm the presence of intact RR2, the tetO, ant6, lnuB, and ant9 genes located upstream, midstream, and downstream of RR2 were detected by PCR and DNA sequencing. RESULTS: A total of 149 cases of neonatal invasive GBS infection were identified during the period 2011-2017. Among them, 119 cases (79.9%) were caused by MDR isolates, with a general increasing trend over the past 7 years. Further characterization of 11 isolates showed that six isolates causing late-onset disease (LOD) carry the tetO, ant6, and lnuB genes, which are located on RR2. Moreover, lnuB and ant9 consistently co-occurred in GBS isolates, which suggests their close proximity to one another in the RR2 gene cluster. CONCLUSION: The MDR GBS is responsible for a large number of neonatal invasive infections and occurs with increasing frequency over time. Particularly, the MDR GBS isolates that cause LOD are more likely to carry the RR2 gene cluster, compared with those that cause early-onset disease. The rise in number of MDR GBS isolates emphasizes the pressing need for continuous surveillance to monitor their antibiotic susceptibility and epidemiology.

Rapamycin enhances HBV production by inducing cellular autophagy.

BACKGROUND: Some reports revealed that rapamycin could reactivate HBV infection. However, the mechanism has not been clearly explained. OBJECTIVES: In this report, we studied the mechanism by which rapamycin enhances HBV replication and expression by inducing cellular autophagy. MATERIALS AND METHODS: HepG2.2.15 cells were treated with rapamycin to induce autophagy. Autophagosomes were observed by fluorescence microscopy and transmission electron microscopy. Autophagy marker protein LC3-Ⅱ/LC3-Ⅰwas detected by Western blotting. HBV DNA and mRNA were determined by real time PCR and Southern blotting. HBsAg was evaluated by ELISA. RESULTS: In HepG2.2.15 cells, HBV DNA and HBsAg increased when host cells were treated with rapamycin and the effect was reversed by autophagy inhibitor, 3-methyladenine (3-MA). CONCLUSIONS: These results indicated a potential explanation for reactivation of HBV infection when patients with hepatitis receive rapamycin.