Distributions of candidate vaccine Targets, virulence Factors, and resistance features of invasive group B Streptococcus using Whole-Genome Sequencing: A Multicenter, population-based surveillance study.

BACKGROUND: Group B Streptococcus (GBS) is a leading cause of morbidity and mortality in young infants worldwide. This study aimed to investigate candidate GBS vaccine targets, virulence factors, and antimicrobial resistance determinants. METHODS: We used whole-genome sequencing to characterize invasive GBS isolates from infants < 3 months of age obtained from a multicenter population-based study conducted from 2015 to 2021 in China. RESULTS: Overall, seven serotypes were detected from 278 GBS isolates, four (Ia, Ib, III, V) of which accounted for 97.8 %. We detected 30 sequence types (including 10 novel types) that were grouped into six clonal complexes (CCs: CC1, CC10, CC17, CC19, CC23 and CC651); three novel ST groups in CC17 were detected, and the rate of CC17, considered a hyperinvasive neonatal clone complex, was attached to 40.6 % (113/278). A total of 98.9 % (275/278) of isolates harbored at least one alpha-like protein gene. All GBS isolates contained at least one of three pilus backbone determinants and the pilus types PI-2b and PI-1 + PI-2a accounted for 79.8 % of the isolates. The 112 serotype III/CC17 GBS isolates were all positive for hvgA. Most of the isolates (75.2 %) were positive for serine-rich repeat glycoprotein determinants (srr1or srr2). Almost all isolates possessed cfb (99.6 %), c1IE (100 %), lmb (95.3 %) or pavA (100 %) gene. Seventy-seven percent of isolates harboured more than three antimicrobial resistance genes with 28.4 % (79/278) gyrA quinoloneresistancedeterminants mutation, 83.8 % (233/278) carrying tet cluster genes and 77.3 % (215/278) carrying erm genes which mediated fluoroquinolone, tetracycline and clindamycin resistance, respectively." CONCLUSIONS: The findings from this large whole-genome sequence of GBS isolates establish important baseline data required for further surveillance and evaluating the impact of future vaccine candidates.

Epidemiological and Clinical Characteristics of Neonatal Ureaplasma urealyticum Infection.

Purpose: To understand the epidemiology and clinical features of Ureaplasma urealyticum (UU) infection in hospitalized neonates due to vertical transmission from mother to child. Methods: Respiratory secretions were collected from neonates hospitalized in the neonatology department of the Maternal and Child Health Hospital of Hubei Province from July 2020 to June 2022, and PCR was used to detect UU-DNA in respiratory secretions. The neonates were divided into UU-positive and UU-negative groups, the epidemiological and clinical characteristics of two groups, were statistically analyzed. Results: A total of 7257 hospitalized neonates were included in this study, of whom 561 were UU positive and 6696 were UU negative, with a UU detection rate of 7.73%. The detection rate among female neonates was higher than male neonates, and the highest detection rate was found in the period from 1-7 days after birth; the detection rate was highest in spring and fall, and the lowest in winter, but the overall difference was not statistically significant (P>0.05). Compared with the UU-negative group, neonates in the UU-positive group were more likely to be preterm, have a lower birth weight, be delivered vaginally, and have maternal preterm rupture of membranes. In addition, neonates in the UU-positive group were more likely to be co-infected with pathogens and to have complications related to UU infections, which were all statistically significant (P<0.05). Conclusion: Neonatal UU infections are detected more frequently in female infants, with the highest detection rate occurring in 1-7 days after birth, and the most prevalent periods for infection being spring and fall. Vaginal delivery and premature rupture of membranes may lead to an increased risk of vertical UU transmission from mother to child, and UU infection is strongly associated with preterm labor, low birth weight, pathogen co-infection, and related complications.

Clinical Features and Antibiotic Treatment of Neonatal Listeriosis: A Hospital-Based Study.

Purpose: To determine the clinical features, laboratory findings, antibiotic treatment, and outcomes of neonatal listeriosis in a specialized tertiary hospital in Wuhan, China. Patients and Methods: We retrospectively analyzed the medical records of patients diagnosed with neonatal listeriosis at Maternal and Child Health Hospital of Hubei Province from January 2015 to December 2022. Listeriosis was indicated by positive culture for Listeria monocytogenes (LM). Results: A total of 11 cases were included in our study. The incidence rate of neonatal listeriosis was 2.06 per 100,000 live births. Seventy-three percent of the cases were born prematurely, caused early onset sepsis. Respiratory distress (100%) was the most common and earliest symptom, followed by fever (64%) and rashes (27%). The levels of C-reactive protein (CRP) and procalcitonin (PCT) were elevated in 100% of the cases. The median time-to-positivity (TTP) of the culture was 15 hours (range 9-28hours). Of the 11 neonates, 6 were cured, 2 showed improvement, and 3 died, with a mortality rate of 27%. There were statistically significant differences in Apgar score at 5 minutes (p=0.037) and CRP (p=0.025) between the survival group and fatality group. Ampicillin was sensitive to LM isolates and effective for therapy if initiated early. Conclusion: Neonatal listeriosis is a rare but severe infection with a high mortality rate. Early identification and appropriate use of effective antibiotics are particularly critical for achieving positive outcomes. Apgar score and CRP are relevant indices for prognosis. Ampicillin is the first-line therapy and can be empirically administered to neonates suspected of having listeriosis.

Serotype Distribution, Virulence Determinants and Antimicrobial Susceptibility of Streptococcus agalactiae Isolated from Young Infants

Background: Streptococcus agalactiae (Group B Streptococcus, GBS) is the most common cause of serious infections in the first 3 months of life worldwide. The pathogenicity of GBS is closely related to serotypes, surface proteins and virulence factors, and the distribution of them may vary temporally and geographically. However, data related to GBS surface proteins and virulence determinants in China are very few. The aim of this study is to investigate the genetic characteristics of clinical GBS isolates from infected infants. Methods: We recovered GBS isolates from infected infants younger than 3 months during 2017−2021 at Maternal and Child Health Hospital of Hubei Province in China. We assessed the GBS serotypes, surface proteins, virulence determinants and antibiotic resistance genes distribution, by Multilocus sequence typing (MLST) and whole-genome sequencing analysis. Results: Among 97 isolates (81 EOD and 16 LOD), 5 serotypes were detected. Serotype III was the most represented (49.5%), followed by type Ib (20.6%). The isolates belonged to 17 different sequence types (STs) that grouped into the 8 clonal complexes (CCs). The most frequently identified ST was ST17 (23.7%). The most predominant surface protein of alpha-protein-like (alp) family (one of the protein components of the GBS surface antigen, resistant to trypsin) present was Rib (41.2%), which was mainly detected in serotype III. The srr1, which encodes Srr1 protein, was identified in 54.6% of isolates. The hvgA encoding for hypervirulent GBS adhesin can be detected in all 24 serotype III GBS. Among the pilus islands genes, 50% and 58.8% of the isolates were positive for pi-1 and pi-2a genes, respectively. The presence of pi-2b was mainly associated with serotype III/CC17 strains; 56.7% of isolates carried tetM, tetO/tetL, ermB antibiotic resistant genes. Among all the virulence genes detected, the cfb-cylE-lmb-pavA pattern was the main virulence gene profile (81.4%), mainly in serotype III/CC17. Conclusions: The whole genomic sequencing data revealed the high variation in surface proteins, determining virulence and antibiotic resistance in clinical isolates from 97 GBS infected infants. These data provide insightful characteristics of genetic features of GBS. Constant epidemiological surveillance is warranted to provide information on the GBS pathogenic dynamics and antibiotic resistance profiles in the surveyed areas for improving therapeutic outcomes.

Trends and Correlation Between Antimicrobial Resistance and Antibiotics Consumption in a Specialist Children's Hospital from 2016 to 2021.

Purpose: To explore the trends and correlation between antibiotics consumption and antimicrobial resistance in children in a specialist hospital from 2016-2021 in China. Patients and Methods: This retrospective study investigated data on the consumption of antibiotics and antimicrobial resistance in children. Antibiotics consumption was expressed as defined daily doses (DDDs)/1000 patient-days based on the Guidelines for Anatomical Therapeutic Chemical. The trends in antibiotics consumption and antimicrobial resistance rates were analyzed by linear regression, while Spearman correlation analysis was employed to evaluate their correlations. Results: An increasing trend in the annual consumption of carbapenems and monobactams was detected (all P<0.05). A significant upward trend was detected in the annual resistance rates of Enterococcus faecium to ciprofloxacin, Streptococcus pneumonia to ceftriaxone, Acinetobacter baumannii to carbapenems, Enterobacter cloacae to carbapenems, Pseudomonas aeruginosa to ceftazidime, and Escherichia coli to cefepime, while the annual resistance rates of Escherichia coli to carbapenems had a significant downward trend (all P<0.05). The consumption of cephalosporin/ß-lactamase inhibitor (C/BLI) combinations and carbapenems had significant positive correlations with the resistance rates of Acinetobacter baumannii to carbapenems (r=0.763, P<0.001; r=0.806, P<0.001), Enterobacter cloacae to carbapenems (r=0.675, P<0.001; r=0.417, P=0.043), and Pseudomonas aeruginosa to ceftazidime (r=0.625, P=0.001; r=0.753, P<0.001), respectively. Also, increasing consumption of monobactams was related to the upward resistance rates of Acinetobacter baumannii to carbapenems (r=0.557, P=0.005) and Enterobacter cloacae to carbapenems (r=0.507, P= 0.011). Conclusion: This study demonstrated significant positive associations between antibiotics consumption and specific antimicrobial resistance rates. The current findings pointed out some directions to pursue in controlling the prevalence of certain resistant bacterial strains in children.

Highly Sensitive and Specific Detection of Mobilized Colistin Resistance Gene mcr-1 by CRISPR-Based Platform.

Mobilized colistin resistance (mcr-1) gene mediated by plasmid can cause the speediness dissemination of colistin-resistant strains, which have given rise to a great threat to the treatment of human infection. Hence, a rapid and accurate diagnosis technology for detecting mcr-1 is essential for the control of resistance gene. Here, a recombinase polymerase amplification (RPA) coupled with CRISPR/Cas12a platform was established for rapid, sensitive, and specific detection of mcr-1 gene. The analytical sensitivity of our assay is 420 fg per reaction in pure mcr-1-positive isolates, and the threshold of this method in spiked clinical samples was down to 1.6 × 103 ~ 6.2 × 103 CFU/mL (1.6 ~ 6.2 CFU/reaction). Moreover, the RPA-CRISPR/Cas12a system perspicuously demonstrated no cross-reactivity with other resistant genes. The entire experimental process included rapid DNA extraction (15 min), RPA reaction (30 min), CRISPR/Cas12a cleavage (5 min), and fluorescence testing (<10 min), which could be completed within 60 min. In summary, the RPA-CRISPR/Cas12a assay designed here provides a rapid diagnostic way for monitoring mcr-1 in clinic and livestock farm. IMPORTANCE This study promises a rapid and accurate assay (RPA-CRISPR/Cas12a) for the surveillance of mcr-1 gene, which causes the efficacy loss of colistin in clinical treatments. In addition, the established method is fit for "on-site" surveillance especially.

Molecular epidemiological characteristics of carbapenem-resistant Klebsiella pneumoniae among children in China.

Klebsiella pneumoniae infection and antimicrobial resistance among children are major concerns. The occurrence of hypervirulent K. pneumoniae (hvKp) infections is gradually increasing worldwide, and disinfectant resistance is also being reported. Carbapenem- and disinfectant-resistant hvKp infection has made clinical treatment and nosocomial infection control among children increasingly challenging. In this study, whole-genome sequencing was conducted among 34 Carba NP-positive carbapenem-resistant K. pneumoniae (CRKP) strains, and the distribution of antibiotic resistance genes, virulence genes and disinfectant resistance genes was determined. Eleven distinct STs were identified, and most of them were ST11 (58.8%). Among the carbapenem resistance genes, KPC-2 was predominant (61.8%), followed by NDM-1 (26.5%) and IPM-4 (11.8%), and no other carbapenemase genes were found. Twelve virulence genes were investigated. All 34 CRKP strains carried the following virulence genes: rcsA/B, entA, fimA/H and mrkA/D. The gene iucB was present in only 3 (8.9%) CRKP strains. The positive detection rates of the iroN and ybtA genes were 94.1% and 64.7%, respectively. None of the strains was found to carry the rmpA and iroB genes. Two disinfectant resistance genes were investigated in this study. Twenty-one (61.8%) strains carried both the qacE and cepA disinfectant resistance genes, 13 (38.2%) CRKP strains carried only the cepA gene, and no strains with only the qacE gene was detected. The correlations among virulence, drug resistance and disinfectant tolerance showed that the virulence and disinfectant resistance genes were distinct among several types of carbapenemase-producing CRKP strains.

Clinical Laboratory Features of Microbes That Cause Neonatal Sepsis: An 8-Year Retrospective Study.

Purpose: To determine the distribution and antibiotic resistance patterns among pathogens that cause neonatal sepsis (NS) and to assess trends in antibiotic resistance. Patients and methods: A total of 864 patients with sepsis admitted to a neonatal intensive care unit (NICU) between 2014 and 2021 were enrolled. Data on neonate age and sex, pathogenic microbes, and antimicrobial susceptibility were collected. Univariate and linear regression analyses were performed to determine the differences and trends in antibiotic resistance rates. Results: The overall incidence rate of NS was 4.59 cases per 1000 live births. Of these cases, 255 (29.5%) were early-onset neonatal sepsis (EONS) and 609 (70.5%) were late-onset neonatal sepsis (LONS). A total of 670 (70.5%) gram-positive cocci and 171 (19.8%) gram-negative bacilli were identified. Among the 552 coagulase-negative Staphylococcus (CoNS) strains, the rate of oxacillin resistance was 70.6%, but no strains were resistant to linezolid, vancomycin or tigecycline. Among the antibiotic resistance patterns of the top three gram-negative pathogens, K. pneumoniae showed the highest rates of resistance, with resistance rates of 37.9% and 39.4% to ertapenem and imipenem, respectively, while E. coli and Enterobacter cloacae showed high levels of susceptibility to both. With regard to the trends in resistance among important pathogens, the rates of resistance to rifampicin, ciprofloxacin, levofloxacin, moxifloxacin and clindamycin by Staphylococcus epidermidis significantly decreased (p<0.05) during the study period. E. coli strains exhibited a significant increase in ceftriaxone resistance during the study period (p<0.05). Conclusion: CoNS was the main microbe that caused NS, followed by E. coli. The bacterial isolates showed varying levels of resistance to the antimicrobial drugs tested. Thus, periodic surveillance in hospital settings to monitor changes in pathogens and antibiotic resistance is important.

Bacteriological Profile and Antibiotic Susceptibility Pattern of Neonatal Septicemia and Associated Factors of ICU Hospitalization Days.

PURPOSE: To evaluate the microorganisms involved in neonatal septicemia and its antibiotic susceptibility pattern and to further investigate the factors associated with the length of intensive care unit (ICU) stay in neonatal septicemia. PATIENTS AND METHODS: A total of 297 infants with septicemia at neonatal ICU (NICU), Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology from 2016 to 2020 were enrolled. Identification of bacterial species was done using the standard positive blood culture. Data included demographics, signs at time of septicemia, laboratory values, patient sources, complications, microbiologic characteristics, and the duration of ICU stay. Univariate and multivariate gamma regression analyses were applied to determine the variables associated with ICU stay. RESULTS: The result demonstrated that the main causative pathogens of neonatal septicemia in our hospital were Gram-positive bacteria, among which Staphylococcus epidermidis (100 isolates, 47.17%) was the main conditional pathogens; Escherichia coli (27 isolates, 49.09%) was most frequently isolated among Gram-negative pathogens. Gram-positive bacteria had higher susceptibility to vancomycin, tigecycline and linezolid. Escherichia coli was susceptive to piperacillin (27/27, 100.00%), cefotetan (27/27, 100.00%), meropenem and imipenem (27/27, 100.00%). Streptococcus agalactiae (95% CI: 0.140-0.539), for patients who were transferred from other hospital (95% CI: 0.016 to 0.354), septicemia during hospitalization (95% CI: 0.411 to 0.825), the use of antibacterial drug during pregnancy (95% CI: 0.362 to 2.136), feeding intolerance (95% CI: 0.127 to 0.437), bradycardia (95% CI: 0.196 to 0.838), septicemia newborns have complications (95% CI: 0.063 to 0.291), the onset age (95% CI: 0.006 to 0.023), TRIPS score (95% CI: 0.005 to 0.016), and CRP level (95% CI: 0.002 to 0.005) were related to prolonged ICU stay days. CONCLUSION: This study summarized common pathogens and associated drug sensitivity, and factors influencing ICU stay length. Prevention and control policy in the NICU should be strengthened.

Clinical and Molecular Epidemiology of Invasive Group B Streptococcus Disease among Infants, China.

Invasive group B Streptococcus (GBS) remains a leading cause of illness and death among infants globally. We conducted prospective and retrospective laboratory-based surveillance of GBS-positive cultures from infants <3 months of age in 18 hospitals across China during January 1, 2015-December 31, 2017. The overall incidence of GBS was 0.31 (95% CI 0.27-0.36) cases/1,000 live births; incidence was 0-0.76 cases/1,000 live births across participating hospitals. The case-fatality rate was 2.3%. We estimated 13,604 cases of GBS and 1,142 GBS-associated deaths in infants <90 days of age annually in China. GBS isolates were most commonly serotype III (61.5%) and clonal complex 17 (40.6%). Enhanced active surveillance and implementation of preventive strategies, such as maternal GBS vaccination, warrants further investigation in China to help prevent these infections.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometric identification and antifungal susceptibility analysis of Candida species isolated from patients with invasive yeast infections in five university hospitals.

In this multicenter study, we compared the performance of the Bruker Biotyper MS system and VITEK 2 YST systems for invasive yeast identification, investigated the distribution of isolated species, and evaluated the antifungal susceptibility profiles of Candida albicans, Candida parapsilosis, and Candida tropicalis. In cases of discrepant results lack of identification with either method, molecular identification techniques were employed. We tested 216 clinical isolates, and concordance between the two methods was observed for 192/216 isolates (88.9%). For five unidentified strains (2.3%), an internal transcribed spacer (ITS) sequencing approach was used. In brief, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) provided short turnaround times and more reliable results than those of Vitek 2 YST. In Wuhan, C. albicans, C. parapsilosis, Candida glabrata, and C. tropicalis were the most common pathogens (93.0%) in patients with candidemia. Cryptococcus neoformans was mainly detected in cerebrospinal fluid samples (88.9%). Trichosporon asahii were all isolated from drainage fluids in the Surgery. Candida albicans was clearly susceptible to azoles, while C. parapsilosis and C. tropicalis displayed differences in susceptibility to azoles. Our findings provide a basis for the practical application of MALDI-ToF MS for identification and for the use of ATB FUNGUS 3 to characterize the susceptibility of Candida spp., thereby providing significant data for therapeutic decisions.

Characterization of group B Streptococcus isolated from sterile and non-sterile specimens in China.

Group B streptococcus (GBS) is a leading cause of invasive neonatal infections and has increasingly been associated with invasive diseases in non-pregnant adults. We collected 113 GBS isolates recovered from sterile and non-sterile specimens from seven tertiary hospitals in China between October 2014 and September 2016. Medical records were retrospectively reviewed and the sequence types, serotypes, virulence, and antimicrobial resistance profiles of the isolates were characterized and correlated. Significantly higher C-reactive protein and procalcitonin levels and absolute neutrophil counts were observed in patients with invasive infections than in those with non-invasive infections (P < 0.05). The 113 isolates were grouped into 24 sequence types, 5 clonal complexes, and 6 serotypes. multivariate analysis revealed that clonal complex 17 isolates characterized by serotype iii, the surface protein gene rib, and the pilus island pi-2b were independently correlated with invasive infection (or: 6.79; 95% ci: 2.31-19.94, P < 0.001). These results suggest alternative molecular biomarkers for diagnosis and prognosis of GBS infections.

Disease burden and antimicrobial resistance of invasive group B streptococcus among infants in China: a protocol for a national prospective observational study.

BACKGROUND: Group B Streptococcus (GBS) is a cause of neonatal sepsis, pneumonia, and meningitis that can lead to neurological sequelae in infants less than 3 months of age. The GBS disease burden is not known in China, therefore it cannot receive major attention. The main objectives of this study are the evaluation of the incidence of neonatal GBS infection, GBS case-fatality ratio, its serotypes and genotypes, bacterial resistance, clinical treatment and outcomes in China. METHODS: We are conducting a nation-wide, population-based, multi-center, prospective, observational cohort study in China from May 2016 to December 2017. Eighteen large urban tertiary care hospitals from 16 provinces were selected that cover the eastern, southern, western, northern and central regions of China. Meanwhile, we retrospectively collected data and GBS strains from January 2015 to April 2016 from selected hospitals. The incidence rate per 1000 live births will be defined as the total number of confirmed GBS cases born in the selected hospitals divided by the number of live births in the hospitals during the study period. All GBS cases detected in selected hospitals will be used to calculate the case-fatality ratio and for the typing analysis. GBS isolates will be serotyped using the Strep-B-Latex® rapid latex agglutination test for serotyping of Group B streptococci. Multi-locus sequence typing (MLST) will be performed by sequencing the internal fragments of seven house-keeping genes. Antimicrobial susceptibility will be tested per interpretive standards established by the Clinical and Laboratory Standards Institute. The presence of the common resistance genes ermA, ermB, mefA, tetI, tetO and tetM will be tested by PCR. DISCUSSION: We are conducting the first national study to estimate the invasive GBS disease burden and antimicrobial resistance of GBS among infants in China. Study findings will provide important evidence for improving clinical practice to ensure timely diagnosis of GBS disease and decisions for preventive measures. Surveillance of antimicrobial resistance will promote the rational use of antimicrobials. TRIAL REGISTRATION: The study was retrospectively registered at http://clinicaltrials.gov on June 13, 2016. It was granted a registration number of "NCT02812576".

[A case-control study on the risk factors of nosocomial infection caused by imipenem-resistant Pseudomonas aeruginosa].

OBJECTIVE: To explore the risk factors for nosocomial infection caused by imipenem-resistant Pseudomonas aeruginosa (IRPA). METHODS: A case-control study was carried out for the comparison of 2 groups of 'case' patients with 'controlled' patients. The first group of 'case' patients had nosocomial isolation of IRPA, and the second group had imipenem-susceptible Pseudomonas aeruginosa (ISPA). 'Control' patients were selected from the same medical or surgical services from which 'case' patients were receiving care when isolation of IRPA or ISPA occurred. Risk factors analyzed included the use of antimicrobials, comorbid conditions, and demographic variables. IRPA was recovered from 67 patients, and ISPA from 150 patients while the control case were 200 and 159 respectively. All patients were from Renmin Hospital of Wuhan University during Jan 2002 to Dec 2003. Data were analyzed with unconditional logistic regression and principal component analysis. RESULTS: Data from multivariate unconditional logistic regression analysis showed that the independent risk factors for IRPA nosocomial infection were: time at risk (OR = 1.03, 95% CI: 1.01-1.04), imipenem (OR = 4.65, 95% CI: 1.35-11.52), PIP/TAZ (OR = 3.37, 95% CI 1.85-9.43) and quinolones (OR = 1.85, 95% CI: 1.25-5.34) while the third cephalosporins (OR = 2.54, 95% CI: 1.26-5.23) and aminoglycoside antibiotics (OR = 1.86, 95% CI 1.42-3.26) time at risk (OR = 1.05, 95% CI: 1.03-1.05) were associated with isolated ISPA. CONCLUSION: Nosocomial infection of IRPA could be caused by the use of imipenem and other antibiotics, suggesting that to limit the use of imipenem was not sufficient to contain the increasing incidence of IRPA.