[A retrospective cohort study on the correlation between early energy management and bronchopulmonary dysplasia in premature infants]

Objective: To investigate the correlation between early energy supplement and bronchopulmonary dysplasia (BPD) in very preterm and very low birth weight infants. Methods: A retrospective cohort study design was used. A total of 939 preterm infants who were admitted to the Department of Neonatology of the West China Second Hospital of Sichuan University within 24 h after birth from January 2019 to December 2021 were enrolled in the study. They were born with a gestational age of <32 weeks and (or) a birth weight of <1 500 g. Of them, 250 preterm infants who developed BPD were enrolled in the BPD group, and each of them was matched to a preterm infant who did not develop BPD (matched for gestational age and birth weight) in the order of priority after calculating propensity score. Their total energy, enteral energy, parenteral energy, total fluid intake and energy per unit of fluid per week were collected within the first 2 weeks of life. The independent sample t-test or Mann Whitney U test was used for continuous variables, and the χ2 test for between-group comparisons of categorical variables. Univariate and multivariate Logistic regression analyses were used to explore the association between total energy and total fluid and BPD incidence, respectively. The dose-response relationship between parenteral energy and BPD was investigated by a generalized additive model, and the threshold effect of parenteral energy on BPD used a two-piecewise linear regression model. Results: The gestational age was (28.4±1.9) weeks in the BPD group and (29.5±1.3) weeks in the control group; the birth weight was (1 107±258) g in the BPD group and (1 324±261) g in the control group; and there were 140 males (56.0%) and 131 males (52.4%) in each group, respectively. An increase in energy per unit of fluid in the second week of life was associated with a reduced risk of BPD (OR=0.32, 95%CI 0.12-0.84, P=0.021), and an increase in total energy in the second week of life was also associated with a reduced risk of BPD, with total energy of >418-502 kJ/(kg·d) was significantly lower than when total energy was ≤334 kJ/(kg·d) (OR=0.15, 95%CI 0.03-0.85, P=0.033). There was no association between the average total fluid intake and BPD incidence (both P>0.05) in the first and second week. The increase in the proportion of parenteral energy to total energy in the second week of life was associated with an increased incidence of BPD (OR=8.45, 95%CI 2.14-33.32, P=0.003); specifically, the risk of BPD significantly increased when the parenteral energy was ≥305 kJ/(kg·d) (OR=1.02, 95%CI 1.01-1.03, P=0.003). Conclusions: Maintaining a high total energy supply in the early postnatal period in preterm infants may reduce the risk of BPD, but continued reliance on high parenteral energy to meet total energy requirements increases the risk of BPD, so enteral feeds should be initiated as early as possible and maximized as tolerated.

[Characteristics of molecular typing and drug resistance of 67 Salmonella paratyphi A isolated in Zhengzhou from 2013 to 2015]

Objective: To investigate the antimicrobial resistance and pulsed field gel electrophoresis (PFGE) patterns of S.paratyphi A strains in Zhengzhou city isolated from sentinel hospitals in 2013-2015. Methods: According to Salmonella molecular typing and K-B drug susceptibility testing method published by international PulseNet bacterial infectious disease monitoring network and USA Clinical and Laboratory Standards Institute (CLSI2015), we analyzed drug sensitivity and PFGE molecular characteristics of 67 S.paratyphi A strains(11 strains in 2013, 7 strains in 2014, 49 strains in 2015) isolated from blood and stool samples in two sentinel hospitals of fever with rash syndrome surveillance system established in Zhengzhou city in 2013-2015. Results: The results showed 67 strains of S.paratyphi A had different levels of resistance to 13 kinds of antibiotics, 65 strains were multi-drug resistant strains (97.0%), 5 isolates were resistant to 2-3 kinds of antibiotics (7.5%), 41 isolates were resistant to 5-8 kinds of antibiotics (61.2%),11 isolates were resistant to 9-10 kinds of antibiotics(16.4%),8 isolates were resistant to 11-12 kinds of antibiotics(11.9%). 67 strains of S.paratyphi A were divided into 10 molecular patterns(PTYA1-PTYA10) by digestion with XbaⅠ restriction endonuclease and pulsed field gel electrophoresis, each pattern contains 1-48 strains with similarity ranged from 94.31%-100%. PTYA3 contained 48 strains, which was predominant band type; PTYA1, 9 contained 6 strains; PTYA 2, 4, 5, 6, 7, 8, 10 contained 1 strains among them. Conclusion: The status of drug resistance of clinical isolates of S.paratyphi A in Zhengzhou city was rather serious, PFGE patterns showed diversity and dominant characteristics. The PFGE patterns of partial strains and its corresponding anti-drug spectrum have certain relevance and cluster relationship.

[Distribution and molecular type of Salmonella from external environment in Henan province]

Objective: To understand the distribution of Salmonella in external environment in Henan province, and explore the distribution of different serotypes of the Salmonella and their homology. Methods: A total of 4 488 samples were collected form animal dung, meat products and kitchen utensils, and identified by biochemical tests and serotyped by serum agglutination reaction. The predominant serotypes were further typed by PFGE. Results: A total of 324 Salmonella strains were detected in these samples, the detection rate was 7.21%. The 324 Salmonella isolates belonged to 39 serotypes, S. enteritidis (24.07%, 78/324) and S. derby (20.37%, 66/324) were predominant. Forty six strains of S. enteritidis and 30 strains of S. derby were divided into 12 and 17 molecular patterns by digestion with Xba Ⅰ, while chicken and swine were the predominant animal hosts. Conclusions: Serotyping of external environment Salmonella were phenotypically diverse and the serotype of Salmonella from different sources were different. The same clone was prevalent in same area. It is necessary to strengthen supervision and surveillance to ensure food safety.

[Etiology and drug resistance of non-typhi Salmonella in Henan province, 2011-2015]

Objective: To analyze the serotypes and antibiotic resistance phenotypes of non-typhi Salmonella strains in Henan province from 2011 to 2015. Methods: The stool samples were collected from diarrhea patients, and enriched with SBG enrichment broth and the pathogen isolation was conducted with CHROMAgar selective culture medium at 37 ℃ for 18-24 hours using KIA/MIU biochemical action and API20E biochemical system slab to identify Salmonella strains. The serotypes of all the positive strains were detected with SSI Salmonella typing sera. According to K-B drug susceptibility testing method published by USA clinical and Laboratory Standards Institute (CLSI), the antibiotics resistant phenotype of the positive strains were analyzed. Results: A total of 1 351 strains of non-typhi Salmonella were isolated, in which 811 were from males, 540 were from females. The ratio of men to women was 1.5∶1. Children and young adults were mainly affected. The pathogen isolation was mainly in May-October during a year. The 1 351 strains of non-typhi Salmonlla were divided into 58 serotypes. S. enteritidis, S. typhimurium, S. agona, S. derby, S. indiana, S. senftenberg and S. thompson ranked 1^st-7^th. The drug-resistance rate of the 1 351 strains was 46.1% to synthetic broad-spectrum penicillin ampicillin (AMP), 19.5% and 21.2% to the three generation cephalosporin ceftazidime (CAZ) and cefotaxime (CTX), 8.8% to the four generation cephalosporins cefepime (FEP), 58.7% to the one generation of quinolones nalidixic acid (NAL), 14.7% to the three generation fluoroquinolone ciprofloxacin (CIP) and norfloxacin (NOR), 25.0% and 35.6% to aminoglycoside antibiotic gentamicin (GEN) and streptomycin (STR), 35.4% to amphenicols (CHL), 31.7% to sulfonamide trimethoprim (TMP) and 37.8% to tetracycline (TET). Totally 879 strains were multidrug resistant (65.1%): 350 strains were resistant to 3-4 kinds of antibiotics (25.9%), 309 strains were resistant to 5-7 kinds of antibiotics (22.9%), 174 strains were resistant to 8-10 kinds of antibiotics (12.9%) and 48 strains were resistant to 11-12 kinds of antibiotics (3.6%). Conclusion: The serotypes of non-typhi Salmonella strains isolated from Henan province varied, some strains were resistant to 12 kinds of antibiotics commonly used in clinical treatment and the multidrug resistance has become serious.

[The etiological and molecular typing research of diarrheagenic Escherichia coli in Henan province in 2013]

OBJECTIVE

To analyze the distribution and pulsed field gel electrophoresis (PFGE) patterns of five kinds of diarrheagenic Escherichia coli (DEC) in infected diarrhea population of Henan province in 2013.

METHODS

Gathering 1 037 strains of E. coli of 1 037 diarrhea patients from four sentinel hospitals of multi-pathogen monitoring system in Henan province in 2013. Stool samples were cultured with Mac agar plates and using KIA/MIU biochemical action as the preliminary method to identify E. coli strains; preparation of DNA template with thermal cracking method and using multiplex PCR to detect five kinds of DEC. According to molecular typing method published by the international PulseNet bacterial infectious disease monitoring network, the PFGE molecular characteristics of DEC strains were analyzed.

RESULTS

125 DEC positive strains were detected in 1 037 strains of E. coli, the total detection rate was 12.05%. 90 strains were enteroaggregative E.coli (EAEC), detection rate was 8.68% (n=90); 24 strains were enteropathogenic E.coli (EPEC), detection rate was 2.31%; 7 strains were enteroinvasive E.coli (EIEC), detection rate was 0.68%; 4 strains were enterotoxigenic E.coli (ETEC), detection rate was 0.39%; enterohemorrhagic E.coli (EHEC) was not detected. 639 cases of diarrhea samples were collected from male patients, 398 cases were from female patients, 94 positive cases were from male patients, the detection rate was 14.71%.The positive number of female cases were 31 cases, the detection rate was 7.79%. 97 positive cases were detected from 782 countryside cases and 28 positive cases were detected from 255 urban area cases, with detection rate 12.40% and 10.98% respectively. In 125 cases of DEC positive samples, children below 5 years old were 83 cases, accounting for 66.4%; 53 strains of EAEC were divided into 52 molecular patterns by digestion with XbaⅠ and pulsed field gel electrophoresis, each pattern contained 1-2 strains with similarity ranged from 66.3%-100%; 18 strains of EPEC were divided into 18 molecular patterns, each pattern contains 1 strain with similarity ranged from 72.6%-94.8%; 5 strains of EIEC were divided into 5 molecular patterns, each pattern contains 1 strain with similarity ranged from 71.9%-98.5%. 2 strains of ETEC were divided into 2 molecular patterns and similarity below 70%.

CONCLUSION

Through the research we could find that four kinds of DEC as a pathogenic bacteria took an important component in pathogenic spectrum of bacterial diarrhea of Henan province in 2013. Four kinds of DEC carrying different virulence genes and taking multiple PFGE patterns showed diversity and complexity characteristics.