Crystal Structures of the Acinetobacter baumannii Macrolide Phosphotransferase E.

Acinetobacter baumannii (A. baumannii) challenges clinical infection treatment due to its resistance to various antibiotics. Multiple resistance genes in the core genome or mobile elements contribute to multidrug resistance in A. baumannii. Macrolide phosphotransferase gene mphE has been identified in A. baumannii, which is particularly relevant to macrolide antibiotics. Here, we determined the structure of MphE protein in three states: the apo state, the complex state with erythromycin and guanosine triphosphate (GTP), and the complex state with azithromycin and guanosine. Interestingly, GTP and two magnesium ions were observed in the erythromycin-bound MphE complex. This structure captured the active state of MphE, in which the magnesium ions stabilized the active site and assisted the transfer of phosphoryl groups. Based on these structures, we verified that the conserved residues Asp29, Asp194, His199, and Asp213 play an important role in the catalytic phosphorylation of MphE leading to drug resistance. Our work helps to understand the molecular basis of drug resistance and provides reference targets for optimizing macrolide antibiotics.

Isolate distribution and antifungal susceptibility of Saccharomyces cerevisiae in the national regional medical center of Southwest China for women and children during 2018-2023.

BACKGROUND: Saccharomyces cerevisiae has been considered a harmless yeast, but in recent years, increasing evidence has shown that it can cause disease in humans, especially invasive infections in infants/children and vulvovaginal infections in women. This study aimed to investigate the clinical information and antifungal susceptibility of clinical cases with S. cerevisiae and establish a foundation for the prevention and treatment of fungal infections. METHODS: This study was conducted from May 2018 to May 2023 at a national regional medical center in Southwest China for women and children. The demographic and clinical characteristics of patients isolated with S. cerevisiae were collected and analyzed. All the isolates were cultured on Sabouraud medium plates and identified by MALDI-TOF MS. The antifungal susceptibility of S. cerevisiae to 10 agents (amphotericin B, fluconazole, itraconazole, voriconazole, micafungin, caspofungin, terbinafine and 5-flucytosine) was determined via the microdilution broth method to determine the minimum inhibitory concentrations (MICs). RESULTS: A total of 75 cases of S. cerevisiae isolated from patients with vulvovaginal candidiasis (VVC, 44 cases), pneumonia (13 cases), or diarrhea (18 cases) were included after data review. The MICs of voriconazole and flucytosine for S. cerevisiae isolated from different body sites differed, with higher resistance in intestinal isolates. In this study, S. cerevisiae caused VVC, but there was no clear evidence that it was involved in pneumonia or diarrhea. Compared with those of Candida albicans, the primary pathogen of VVC, the MICs of fluconazole (11.96 ± 5.78 µg/mL vs. 67.64 ± 16.62 µg/mL, p = 0.002), itraconazole (0.77 ± 0.19 µg/mL vs. 2.31 ± 0.53 µg/mL, p = 0.008), voriconazole (0.22 ± 0.09 µg/mL vs. 5.02 ± 1.09 µg/mL, p < 0.001), and terbinafine (10.41 ± 0.84 µg/mL vs. 14.93 ± 4.77 µg/mL, p < 0.001) for S. cerevisiae (isolated from the genital tract) were significantly lower, while those of micafungin (0.14 ± 0.01 µg/mL vs. 0.06 ± 0.01 µg/mL, p < 0.001) and caspofungin (0.27 ± 0.04 µg/mL vs. 0.06 ± 0.01 µg/mL, p < 0.001) were significantly greater. CONCLUSION: Azoles remain the recommended regimen for S. cerevisiae-related VVC, and the use of amphotericin B vaginal effervescent tablets could be considered for the treatment of azole-resistant isolates. The antifungal susceptibility of S. cerevisiae varies according to the isolated source, and the pathogenicity trend of S. cerevisiae should be studied.

Integrating Molecular Biology and Network Pharmacology to Analyze the Antidepressant Mechanism of Glycyrrhizaglabra.

INTRODUCTION: Antidepressants have adverse effects and induce drug resistance when used excessively or frequently. Therefore, adjuvants are needed to reduce the use of antidepressants during treatment. Traditional Chinese medicine (TCM) is an important adjunctive approach to depression with safety, environmental protection, and low toxicity. Glycyrrhizaglabra (licorice, GG) is a plant commonly used in various herbal remedies. METHOD: We investigated the antidepressant activity of GG, its active constituents, and potential depression-related targets. We combined animal behavioral and molecular biological assays with network pharmacology to analyze the antidepressant mechanism of GG. GG extracts reversed lipopolysaccharide (LPS)-induced depression-like behavior in behavioral tests. We selected 56 active compounds and 695 target compounds of licorice from TCMSP. The PPI network screened 80 core targets for enrichment analysis. It shows that GG significantly affected neurodegeneration pathways, neuroactive ligand-receptor interaction, cAMP signaling pathway, serotonergic synapse, dopaminergic synapse, and MAPK signaling pathway. RESULT: Mechanistic studies showed that GG reduced IL-1ß, IL-6, and TNF-α levels, 5-HTRA1 expression, and GSK3ß phosphorylation in mouse hippocampus. It also increased BDNF and DRD1 expression and CREB and ERK1/2 phosphorylation. CONCLUSION: It shows that GG acted on these proteins to affect multiple pathways that mediate the pathogenesis of depression.

Invasive Fusarium solani infection diagnosed by traditional microbial detection methods and metagenomic next-generation sequencing in a pediatric patient: a case report and literature review.

Fusarium solani, as an opportunistic pathogen, can infect individuals with immunosuppression, neutropenia, hematopoietic stem cell transplantation (HSCT), or other high-risk factors, leading to invasive or localized infections. Particularly in patients following allogeneic HSCT, Fusarium solani is more likely to cause invasive or disseminated infections. This study focuses on a pediatric patient who underwent HSCT for severe aplastic anemia. Although initial blood cultures were negative, an abnormality was detected in the 1,3-ß-D-glucan test (G test) post-transplantation. To determine the causative agent, blood samples were subjected to metagenomic next-generation sequencing (mNGS) and blood cultures simultaneously. Surprisingly, the results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and mNGS differed slightly, with mNGS identifying Nectria haematonectria, while MALDI-TOF MS based on culture showed Fusarium solani. To clarify the results, Sanger sequencing was performed for further detection, and the results were consistent with those of MALDI-TOF MS. Since the accuracy of Sanger sequencing is higher than that of mNGS, the diagnosis was revised to invasive Fusarium solani infection. With advancements in technology, various detection methods for invasive fungi have been developed in recent years, such as mNGS, which has high sensitivity. While traditional methods may be time-consuming, they are important due to their high specificity. Therefore, in clinical practice, it is essential to utilize both traditional and novel detection methods in a complementary manner to enhance the diagnosis of invasive fungal infections.

Chloramphenicol Binding Sites of Acinetobacter baumannii Chloramphenicol Acetyltransferase CatB8.

Acinetobacter baumannii is a multidrug-resistant pathogen that has become one of the most challenging pathogens in global healthcare. Several antibiotic-resistant genes, including catB8, have been identified in the A. baumannii genome. CatB8 protein, one of the chloramphenicol acetyltransferases (Cats), is encoded by the catB8 gene. Cats can convert chloramphenicol (chl) to 3-acetyl-chl, leading to bacterial resistance to chl. Here, we present the high-resolution cocrystal structure of CatB8 with chl. The structure that we resolved showed that each monomer of CatB8 binds to four chl molecules, while its homologous protein only binds to one chl molecule. One of the newly discovered chl binding site overlaps with the site of another substrate, acetyl-CoA. Through structure-based biochemical analyses, we identified key residues for chl recruiting and acetylation of chl in CatB8. Our work is of significant importance for understanding the drug resistance of A. baumannii and the effectiveness of antibiotic treatment.

Serotype, antibiotic susceptibility and whole-genome characterization of Streptococcus pneumoniae in all age groups living in Southwest China during 2018-2022.

Background: Streptococcus pneumoniae is a common pathogen that colonizes the human upper respiratory tract, causing high morbidity and mortality worldwide. This study aimed to investigate the prevalence status of S. pneumoniae isolated from patients of all ages in Southwest China, including serotype, antibiotic susceptibility and other molecular characteristics, to provide a basis for clinical antibiotic usage and vaccine development. Methods: This study was conducted from January 2018 to March 2022 at West China Hospital, West China Second University Hospital, First People's Hospital of Longquanyi District (West China Longquan Hospital), Meishan Women and Children's Hospital (Alliance Hospital of West China Second University Hospital) and Chengdu Jinjiang Hospital for Women and Children Health. Demographic and clinical characteristics of 263 pneumococcal disease (PD) all-age patients were collected and analyzed. The serotypes, sequence types (STs), and antibiotic resistance of the strains were determined by next-generation sequencing, sequence analysis and the microdilution broth method. Results: The most common pneumococcal serotypes were 19F (17.87%), 19A (11.41%), 3 (8.75%), 23F (6.46%) and 6A (5.70%). Coverage rates for PCV10, PCV13, PCV15, PCV20 and PCV24 were 36.12, 61.98, 61.98, 63.12 and 64.26%, respectively. Prevalent STs were ST271 (12.55%), ST320 (11.79%), ST90 (4.18%), ST876 (4.18%) and ST11972 (3.42%). Penicillin-resistant S. pneumoniae (PRSP) accounted for 82.35 and 1.22% of meningitis and nonmeningitis PD cases, respectively. Resistance genes msrD (32.7%), mefA (32.7%), ermB (95.8%), tetM (97.3%) and catTC (7.6%) were found among 263 isolates. Most isolates showed high resistance to erythromycin (96.96%) and tetracycline (79.85%), with more than half being resistant to SXT (58.94%). A few isolates were resistant to AMX (9.89%), CTX (11.03%), MEN (9.13%), OFX (1.14%), LVX (1.14%) and MXF (0.38%). All isolates were susceptible to vancomycin and linezolid. Conclusion: Our study provides reliable information, including the prevalence, molecular characterization and antimicrobial resistance of S. pneumoniae isolates causing pneumococcal diseases in Southwest China. The findings contribute to informed and clinical policy decisions for prevention and treatment.

Genomic Characteristics of Carbapenem-Resistant Klebsiella pneumoniae Isolated from Neonatal Patients in Southwest China During 2017-2021.

Objective: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is spreading worldwide, becoming a serious threat to public health. The present study aimed to analyze the molecular epidemiology and drug resistance mechanism of CRKP isolated from neonatal patients in Sichuan, Southwest China. Methods: CRKP isolates were collected from neonatal patients of West China Second University Hospital from June 2017 to June 2021. Antimicrobial susceptibility testing was performed using broth microdilution. Whole-genome sequencing of all isolates were performed to determine the antimicrobial resistance genes, sequence typing, phylogenetic relationships. Results: In total, 41 nonduplicate CRKP isolates were collected. All isolates were highly resistant to the cephalosporins and carbapenems, however, they were all susceptible to amikacin, tigecycline, ciprofloxacin, and colistin. Various resistance genes were detected, blaNDM-5 (n = 35, 85.4%) was the predominant carbapenemase genes. The most common replicon type was IncX3, which was harbored by 36 (87.8%) isolates, followed by IncFIB (n = 34, 82.9%), and IncFII (n = 32, 78.0%). The 41 CRKP isolates belonged to 8 sequence types (STs) and ST789 (n = 29, all had blaNDM-5) was the dominant sequence type. Conclusion: The study revealed that blaNDM was the most dominant carbapenemase resistance gene. ST789 CRKP strains carrying blaNDM-5 were a tremendous menace to neonates in this hospital. Therefore, effectively implement prevention and control measures need to be taken for the prevention and treatment of CRKP infection in the neonatal ward.

Antibiotic Resistance of Hemophilus influenzae Isolated from Children in Southwest China.

BACKGROUND: Hemophilus influenzae (Hi) is one of the major pediatric bacterial pneumonia pathogens that heavily threatens children's lives and global health. With widespread usage as first-line treatment, the prevalence of ß-lactam-resistant strains is increasing sharply. In order to treat Hi more effectively, a systematic study on the antibiotic resistance profiles, ß-lactamase-negative ampicillin-resistant (BLNAR) strains isolation rate, and potential BLNAR resistance mechanism in our region is needed. METHODS: This study analyzed antimicrobial susceptibility of Hi, and clinical data of Hi-infected patients retrospectively. BLNAR and ß-lactamase-positive ampicillin-clavulanate resistant strains (BLPACR) were confirmed by the Kirby-Bauer method and ß-lactamase test. ftsI gene in BLNAR was sequenced to find out whether resistance was induced by penicillin-binding protein mutation. Ampicillin susceptibility test with or without efflux pump inhibitors were done to assess efflux pump contribution in BLNAR. RT-PCR was performed to evaluate the efflux pump genes' transcription levels. RESULTS: A total of 2,561 Hi strains were isolated in our hospital from January 2016 to December 2019. Male to female ratio was 1.52:1. Median age was 10 months. Infant (< 3 years old) infection accounted for 83.72%. Hi resistance rates to sulfamethoxazole-trimethoprim, ampicillin, cefathiamidine, cefaclor, cefuroxime, cephalothin, amoxicillin-clavulanate, tetracycline, chloramphenicol, ofloxacin, cefotaxime, and rifampin were 84.28%, 78.01%, 49.80%, 41.98%, 36.58%, 33.64%, 4.55%, 4.1%, 3.37%, 1.77%, 0.99%, and 0.12%, respectively, while 1.33% were BLNAR. BLNARs were classified into four groups by mutation patterns in ftsI gene and most strains were divided to Group Ⅲ/Ⅲ-like. EmrB, ydeA and norM transcription levels in some ampicillin-resistant strains were higher than their sensitive counterparts. CONCLUSIONS: Ampicillin is not sufficiently effective as a first-line Hi infection treatment. However, ampicillin-clavulanate and cefotaxime may be a better choice. Efflux pumps, emrB, ydeA and norM play roles in the high resistance to ampicillin.

ΔNp63α-mediated epigenetic regulation in keratinocyte senescence.

Keratinocyte senescence contributes to skin ageing and epidermal dysfunction. According to the existing knowledge, the transcription factor ΔNp63α plays pivotal roles in differentiation and proliferation of keratinocytes. It is traditionally accepted that ΔNp63α exerts its functions via binding to promoter regions to activate or repress gene transcription. However, accumulating evidence demonstrates that ΔNp63α can bind to elements away from promoter regions of its target genes, mediating epigenetic regulation. On the other hand, several epigenetic alterations, including DNA methylation, histone modification and variation, chromatin remodelling, as well as enhancer-promoter looping, are found to be related to cell senescence. To systematically elucidate how ΔNp63α affects keratinocyte senescence via epigenetic regulation, we comprehensively compiled the literatures on the roles of ΔNp63α in keratinocyte senescence, epigenetics in cellular senescence, and the relation between ΔNp63α-mediated epigenetic regulation and keratinocyte senescence. Based on the published data, we conclude that ΔNp63α mediates epigenetic regulation via multiple mechanisms: recruiting epigenetic enzymes to modify DNA or histones, coordinating chromatin remodelling complexes (CRCs) or regulating their expression, and mediating enhancer-promoter looping. Consequently, the expression of genes related to cell cycle is modulated, and proliferation of keratinocytes and renewal of stem cells are maintained, by ΔNp63α. During skin inflammaging, the decline of ΔNp63α may lead to epigenetic dysregulation, resultantly deteriorating keratinocyte senescence.

Analysis of listeriosis infection cases during pregnancy among 70 131 deliveries.

OBJECTIVE: To provide evidence for the diagnosis of listeriosis through a retrospective study of clinical features and results of pregnant women infected with listeriosis. METHODS: Twenty-nine pregnant women infected with listeriosis visiting West China Second University Hospital affiliated to Sichuan University from July 2010 to February 2019 were included in the retrospective analysis. Data like general information, clinical symptoms, laboratory results, and pathogen detection were analyzed to conclude clinical characteristics. RESULTS: The median age of 29 patients was 28 (18.0-42.0). Nine individuals visited in the second trimester, while 20 in the last trimester. The median course before visiting was 3.4 (0.1-19) days. The main symptoms of the first attendance were fever (21/29), increased white blood cells (26/29), abdominal pain (16/29), and decreased or vanished fetal movements (7/29). Samples where listeria were identified were maternal blood (14 cases), excreta from birth canal (24 cases), placenta (one case), newborn blood (seven cases), newborn sputum (eight cases), newborn excreta from auditory meatus (three cases), cerebrospinal fluid (two cases) and ocular discharge (one case). Inflammation was detected in pathological examination of placenta in all subjects. Among them, three were diagnosed with mild chorioamnionitis; five with moderate chorioamnionitis; nine with moderate-to-severe chorioamnionitis and 12 with severe chorioamnionitis. Among 33 fetuses carried by 29 subjects, fetal outcomes include six miscarriages, nine stillbirths, four newborn deaths immediately after birth and four after treatment discontinuation, nine discharges after successful treatment in hospital, and one death after treatment. As for maternal outcomes, 29 pregnant women all recovered after delivery. CONCLUSION: With the acute onset, high incidence of adverse pregnancy outcomes and low coverage of initial treatment, clinical physicians need to raise the awareness of listeriosis during pregnancy.

The first case of Ochrobactrum intermedium bacteremia in a pediatric patient with malignant tumor.

BACKGROUND: Ochrobactrum spp. are non-fermenting, Gram-negative bacilli that are regarded as emerging human pathogens of low virulence that can cause infections. The first identified case of Ochrobactrum intermedium was reported in 1998 in a liver transplantation patient with liver abcess. There are no reports of infections in pediatric patients. Here, we report the first case of O. intermedium bacteremia in a pediatric patient. CASE PRESENTATION: A two and a half years old male was admitted with fever, chills and nausea. He had been diagnosed as pineoblastoma and underwent surgical resection and chemotherapy. O. intermedium was isolated from his blood cultures and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), however, the Vitek II automated system failed to identify the organism. Then the pathogen was confirmed by 16S rDNA sequencing and average nucleotide identity result (ANI) confirmed the precise identification of O. intermedium at genomic level. In addition, the patient recovered well after antibiotic combined therapy. CONCLUSIONS: This, to our knowledge, is the first case of O. intermedium bacteremia in a pediatric patient with malignant tumor. Traditional biochemical identification methods such as API 20NE or VITEK2 system cannot differentiate O. anthropi and O. intermedium. MALDI-TOF may be a promising tool for rapid identification of microorganisms such as O. intermedium.

Association of small intestinal bacterial overgrowth with nonalcoholic fatty liver disease in children: A meta-analysis.

It has been suggested that small intestinal bacterial overgrowth (SIBO) could cause nonalcoholic fatty liver disease (NAFLD), but this association was not examined in children by meta-analysis. This meta-analysis aimed to determine the association between SIBO and NAFLD in children. The electronic databases PubMed, Embase, and Cochrane Library were searched for studies published before April 22, 2021. The outcome was the association between SIBO and NAFLD. Three studies and 205 children were included. All three studies reported the association between SIBO and NAFLD. Children with SIBO were more likely to have NAFLD (odds ratio = 5.27, 95% confidence interval (CI): 1.66-16.68, P<0.001; I2 = 63.5%, Pheterogeneity = 0.065). When directly pooling the reported relative risks (RR) from two studies, children with NAFLD had an over 2-fold increased relative risk of developing SIBO (RR = 2.17, 05%CI: 1.66-2.82, P<0.001; I2 = 0.0%, Pheterogeneity = 0.837). This meta-analysis reports a possible association between SIBO and NAFLD in children.

WW Domain-Containing E3 Ubiquitin Protein Ligase 1: A Self-Disciplined Oncoprotein.

WW domain-containing E3 ubiquitin protein ligase 1 (WWP1) is a member of C2-WW-HECT E3 ligase family. Although it may execute carcinostatic actions in some scenarios, WWP1 functions as an oncoprotein under most circumstances. Here, we comprehensively review reports on regulation of WWP1 and its roles in tumorigenesis. We summarize the WWP1-mediated ubiquitinations of diverse proteins and the signaling pathways they involved, as well as the mechanisms how they affect cancer formation and progression. According to our analysis of database, in combination with previous reports, we come to a conclusion that WWP1 expression is augmented in various cancers. Gene amplification, as well as expression regulation mediated by molecules such as non-coding RNAs, may account for the increased mRNA level of WWP1. Regulation of enzymatic activity is another important facet to upregulate WWP1-mediated ubiquitinations. Based on the published data, we conclude that WWP1 employs interactions between multiple domains to autoinhibit its polyubiquitination activity in a steady state. Association of some substrates can partially release certain autoinhibition-related domains and make WWP1 have a moderate activity of polyubiquitination. Some cancer-related mutations can fully disrupt the inhibitory interactions and make WWP1 hyperactive. High expression level or hyperactivation of WWP1 may abnormally enhance polyubiquitinations of some oncoproteins or tumor suppressors, such as ΔNp63α, PTEN and p27, and ultimately promote cell proliferation, survival, migration and invasion in tumorigenesis. Given the dysregulation and oncogenic functions of WWP1 in some cancer types, it is promising to explore some therapeutic inhibitors to tune down its activity.

Effect of probiotic supplementation in pregnant women: a meta-analysis of randomised controlled trials.

Probiotics are being used increasingly in pregnant women, whereas the efficiency on pregnancy outcomes is yet lacking. PubMed, Embase and the Cochrane Library were searched. Relative risks (RR) or weighted mean differences (WMD) with 95 % CI were employed to calculate the summary outcomes. A total of eighteen randomised controlled trials (RCT) including 4356 pregnant women were eligible. The summary RR indicated that probiotic supplementation was associated with a significant decrease in the risk of atopic eczema (RR 0·68; 95 % CI 0·58, 0·81; P < 0·001) and eczema (RR 0·79; 95 % CI 0·68, 0·91; P = 0·002) without significant heterogeneity. Probiotic supplementation was associated with a prolonged gestational age (WMD 0·09; 95 % CI 0·04, 0·15; P = 0·001) with insignificant heterogeneity, whereas no significant effect was exerted on birth weight (P = 0·851). The risks of death (RR 0·34; 95 % CI 0·13, 0·91; P = 0·031) and necrotising enterocolitis (NEC) (RR 0·38; 95 % CI 0·18, 0·81; P = 0·012) were significantly reduced in pregnant women receiving probiotics without evidence of heterogeneity. These findings suggested that probiotics in pregnant women were beneficial for atopic eczema, eczema, gestational age, death and NEC.

Invasive Fungal Infection Caused by Geotrichum clavatum in a Child with Acute Leukemia: First Documented Case from Mainland China.

Invasive fungal infections are one of the vital complications among acute leukemia patients undergoing induction chemotherapy. Among them, Geotrichum clavatum infections present extremely rarely with atypical clinical symptoms which make them difficult to diagnose. In this paper, we report a case of infection caused by Geotrichum clavatum in a 10-year old child with acute leukemia, which is the first documented case from mainland China. With underlying childhood leukemia, the child suffered from recurrent bacterial and fungal infection and even underwent abdominal surgery during the treatment. Fortunately, the therapeutic effect was finally achieved by adjusting the treatment program to dual anti-fungal treatment with micafungin and amphotericin B. Information regarding the epidemiological, clinical, and therapeutic features, in this case, shows significant perspectives for anti-fungal treatment for immunocompromised individuals, wherefore the rate of recovery and survival can be achieved.

A study of the correlation between obesity and intestinal flora in school-age children.

With the improvement of living standards and dietary changes, childhood obesity has increased worldwide. This study aimed to understand the differences of intestinal flora structure between obese and normal children at school-age. Using the next generation sequencing platform, Illumina Miseq, 16S rDNA high-throughput sequencing technology, we analyzed the diversity and relative abundance of intestinal flora in 39 obese and 38 normal control school-age children. First, we categorized gut bacteria on the basis of their Operational taxonomic units (OTUs) using the RDP 16s rRNA database in RDP classifier. The alpha (α) diversity was used to measure the diversity within a sample and is calculated as a value for each sample. The beta (ß) diversity was used to compare different samples and to measure the dissimilarity between each other sample. Our results indicated that intestinal flora in obese children showed lower diversity than normal controls. Significant differences of relative abundance of intestinal flora were detected at multiple levels of classifications. Identification of intestinal flora with significant difference between obese and normal children may provide important information to uncover the roles of these specific bacteria in the development of obesity and find new strategy to prevent and treat obesity through intervening the intestinal flora.

The Clinical Characteristics of Neonatal Sepsis Infection in Southwest China.

OBJECTIVE: To identify the pathogens responsible for neonatal sepsis in a high-volume women and children's hospital in Southwest China. METHODS: We retrospectively studied 133 neonates who were admitted to the West China Women and Children's Hospital between 2008 and 2012 for sepsis. The clinical characteristics of the patients were recorded, and the antibiotic sensitivities of the isolated bacteria were determined. RESULTS: All of the included patients had clinical symptoms of sepsis, and subsequent blood cultures confirmed the infection. Almost 80% of patients were infected with coagulase-negative staphylococci (52.8%), Escherichia coli (23.6%), Klebsiella pneumoniae (16.0%) or Staphylococcus aureus (7.5%). Neonates who were infected with gram-negative bacteria, particularly K. pneumoniae, had lower birth weights and were admitted to hospital within 24 hours of birth. Additionally, 87.5% of the isolated K. pneumoniae strains were resistant to third generation cephalosporins. CONCLUSION: Coagulase-negative staphylococci were the most common pathogens found in neonatal sepsis. Moreover, neonatal sepsis caused by gram-negative bacteria was more often observed in newborns of low birth weight. The isolated strains of gram-negative bacteria were highly resistant to cephalosporins. This observation highlights the issue of antibiotic-resistant pathogens in the clinical setting, which poses an added risk to infants presenting with sepsis.

[Preparing Bifidobacteria for Quantitative Detections].

OBJECTIVES: To compare different preparation methods for quantitative real-time PCR (qPCR) detection of Bifidobacteria. METHODS: Standard strains of Bifidobacteria were prepared with concentration gradients using strain DNA, PCR product amplification and purification, and plasmid DNA methods. The concentrations of Bifidobacteria were determined with ultraviolet spectrophotometer and real-time quantitative PCR. RESULTS: Greater than 0.99 R 2 in values of standard curves were achieved by all three preparation methods. The plasmid DNA method obtained a higher level of concentration and purity of Bifidobacteria than the other two methods ( P<0.01). CONCLUSIONS: The plasmid DNA method produces high quality preparations and is more suitable for real-time quantitative PCR, which can provide a reference for the molecular biological detection of Bifidobacteria.