Unveiling the Mutations and Conservation of InlA in Listeria monocytogenes.

Listeria monocytogenes (L. monocytogenes) is a pathogen that is transmitted through contaminated food and causes the illness known as listeriosis. The virulence factor InlA plays a crucial role in the invasion of L. monocytogenes into the human intestinal epithelium. In addition, InlA enhances the pathogenicity of host strains, and different strains of L. monocytogenes contain varying variations of InlA. Our study analyzed a total of 4393 published L. monocytogenes genomes from 511 sequence types (STs) of diverse origins. We identified 300 unique InlA protein sequence types (PSTs) and revealed 45 highly mutated amino acid sites. The leucine-rich repeat (LRR) region was found to be the most conserved among the InlA, while the protein A (PA) region experienced the highest mutation rate. Two new types of mutations were identified in the B-repeat region of InlA. Correspondence analysis (CA) was used to analyze correlations between the lineages or 10 most common sequence types (STs) and amino acid (aa) sites. ST8 was strongly correlated with site 192_F, 454_T. ST7 exhibited a strong correlation with site 51_A, 573_E, 648_S, and 664_A, and it was also associated with ST6 and site 544_N, 671_A, 738_B, 739_B, 740_B, and 774_Y. Additionally, a strong correlation between ST1 and site 142_S, 738_N, ST2 and site 2_K, 142_S, 738_N, as well as ST87 and site2_K, 738_N was demonstrated. Our findings contribute significantly to the understanding of the distribution, composition, and conservation of InlA in L. monocytogenes. These findings also suggest a potential role of InlA in supporting molecular epidemiological tracing efforts.

Large-scale genetic analysis and biological traits of two SigB factors in Listeria monocytogenes: lineage correlations and differential functions.

Introduction: Listeria monocytogenes is a globally distributed bacterium that exhibits genetic diversity and trait heterogeneity. The alternative sigma factor SigB serves as a crucial transcriptional regulator essential for responding to environmental stress conditions and facilitating host infection. Method: We employed a comprehensive genetic analysis of sigB in a dataset comprising 46,921 L. monocytogenes genomes. The functional attributes of SigB were evaluated by phenotypic experiments. Results: Our study revealed the presence of two predominant SigB factors (SigBT1 and SigBT2) in L. monocytogenes, with a robust correlation between SigBT1 and lineages I and III, as well as SigBT2 and lineage II. Furthermore, SigBT1 exhibits superior performance in promoting cellular invasion, cytotoxicity and enhancing biofilm formation and cold tolerance abilities under minimally defined media conditions compared to SigBT2. Discussion: The functional characteristics of SigBT1 suggest a potential association with the epidemiology of lineages I and III strains in both human hosts and the natural environment. Our findings highlight the important role of distinct SigB factors in influencing the biological traits of L. monocytogenes of different lineages, thus highlighting its distinct pathogenic and adaptive attributes.

The Isolation, Genetic Analysis and Biofilm Characteristics of Listeria spp. from the Marine Environment in China.

Listeria monocytogenes is an important pathogen that can cause listeriosis. Despite the growing recognition of Listeria spp. as a foodborne and environmental pathogen, the understanding of its prevalence and characteristics of Listeria spp. in the marine environment remains unknown. In this study, we first investigated the genetic and phenotypic characteristics of Listeria species isolated in a coastal city in China. The findings revealed that the sequence type 87 (ST87) L. monocytogenes, a prevalent clinical and seafood strain in China, dominates in recreational beach sands and possesses a notable biofilm-forming capacity in seawater. The presence of ST87 L. monocytogenes in coastal environments indicates the potential health risks for both recreational activities and seafood consumption. Moreover, the ST121 isolates from sand had a versatile plasmid encoding multifunctional genes, including uvrX for UV resistance, gbuC for salt resistance, and npx for oxidative resistance and multiple transposases, which potentially aid in survival under natural environments. Black-headed gulls potentially facilitate the spread of L. monocytogenes, with similar ST35 strains found in gulls and beach sand. As a reservoir of microbes from marine environments and human/animal excrement, coastal sand would play an important role in the spread of L. monocytogenes and is an environmental risk for human listeriosis.

Bacterial taxonomic and functional profiles from Bohai Sea to northern Yellow Sea.

Microbial distribution patterns are the result of a combination of biotic and abiotic factors, which are the core issues in microbial ecology research. To better understand the biogeographic pattern of bacteria in water environments from the Bohai Sea to the northern Yellow Sea, the effects of environmental factors, and spatial distance on the structure of bacterial communities in marine water were investigated using high-throughput sequencing technology based on 16S rRNA genes. The results showed that Proteobacteria, Bacteroidetes, Actinobacteri, Desulfobacterota, and Bdellovibrionota were the dominant phyla in the study area. A clear spatial pattern in the bacterial community was observed, and environmental factors, including salinity, nutrient concentration, carbon content, total phosphorus, dissolved oxygen, and seawater turbidity emerged as the central environmental factors regulating the variation in bacterial communities. In addition, the study provides direct evidence of the existence of dispersal limitation in this strongly connected marine ecological system. Therefore, these results revealed that the variation in bacterial community characteristics was attributed to environmental selection, accompanied by the regulation of stochastic diffusion. The network analysis demonstrated a nonrandom co-occurrence pattern in the microbial communities with distinct spatial distribution characteristics. It is implied that the biogeography patterns of bacterial community may also be associated with the characteristics of co-occurrence characterize among bacterial species. Furthermore, the PICRUSt analysis indicated a clear spatial distribution of functional characteristics in bacterial communities. This functional variation was significantly modulated by the environmental characteristics of seawater but uncoupled from the taxonomic characteristics of bacterial communities (e.g., diversity characteristics, community structure, and co-occurrence relationships). Together, this findings represent a significant advance in linking seawater to the mechanisms underlying bacterial biogeographic patterns and community assembly, co-occurrence patterns, and ecological functions, providing new insights for identifying the microbial ecology as well as the biogeochemical cycle in the marine environment.

Synergistic Immunity and Protection in Mice by Co-Immunization with DNA Vaccines Encoding the Spike Protein and Other Structural Proteins of SARS-CoV-2.

The emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has generated recurring worldwide infection outbreaks. These highly mutated variants reduce the effectiveness of current coronavirus disease 2019 (COVID-19) vaccines, which are designed to target only the spike (S) protein of the original virus. Except for the S of SARS-CoV-2, the immunoprotective potential of other structural proteins (nucleocapsid, N; envelope, E; membrane, M) as vaccine target antigens is still unclear and worthy of investigation. In this study, synthetic DNA vaccines encoding four SARS-CoV-2 structural proteins (pS, pN, pE, and pM) were developed, and mice were immunized with three doses via intramuscular injection and electroporation. Notably, co-immunization with two DNA vaccines that expressed the S and N proteins induced higher neutralizing antibodies and was more effective in reducing the SARS-CoV-2 viral load than the S protein alone in mice. In addition, pS co-immunization with either pN or pE + pM induced a higher S protein-specific cellular immunity after three immunizations and caused milder histopathological changes than pS alone post-challenge. The role of the conserved structural proteins of SARS-CoV-2, including the N/E/M proteins, should be investigated further for their applications in vaccine design, such as mRNA vaccines.

Role of Mitophagy-based TLR9 Signal Pathway in Neonatal Ventilator-induced Lung Injury.

The study focused on the role of mitophagy in neonatal ventilator-induced lung injury (VILI). Immunoassays were used to study the TLR9 signaling pathway of neonatal VILI, expected to provide a feasible solution for neonatal VILI. The mice were randomly divided into four groups, group A: spontaneous breathing group; group B: normal tidal volume (VT) group (VT=9mL/kg); group C: high VT group (VT=39mL/kg); and group D: ODN2088 (400µg/ Only) intervention + high VT group. The four groups were compared for the expression of inflammatory factors. It was found that as the culture time increased, the expression of TLR9, MyD88, and NF-κBp65 in the lung tissue of the large VT group was significantly higher than those in the spontaneous breathing group and normal VT group, and the differences were statistically significant; and TLR9 inhibitors could activate the TLR9-MyD88 signaling pathway to up-regulate the expression of NF-κB, mediating the release of inflammatory factors to cause VILI.

MiR-122-5p regulates the pathogenesis of childhood obesity by targeting CPEB1.

BACKGROUND: Childhood obesity is strongly associated with inflammation which contributes to the development of several obesity-related disorders. Accumulating evidence has suggested that microRNAs (miRNAs) are involved in the pathogenesis of multiple human diseases, including childhood obesity. MiR-122-5p was reported to be related to obesity in childhood, however, the detailed function and mechanism of miR-122-5p are still obscure. METHODS: Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were cocultured with macrophage cell line THP-1 or macrophage-conditioned medium (MacCM) to promote cytokine expression. Oil Red O staining was used to detect the accumulation of lipid droplets in SGBS cells. The expression of interleukin 6 (IL-6), IL-8, and monocyte chemoattractant protein 1 (MCP-1) at mRNA and protein levels was assessed by RT-qPCR and ELISA, respectively. Western blotting was used for measuring protein levels of target genes of miR-122-5p. The luciferase reporter assay was applied for detecting the binding relation between miR-122-5p and cytoplasmic polyadenylation element binding protein 1 (CPEB1). RESULTS: Coculture of SGBS adipocytes and THP-1 macrophages/MacCM promoted IL-6, IL-8, and MCP-1 expression at mRNA and protein levels. Overexpression of miR-122-5p inhibited IL-6, IL-8, and MCP-1 expression in SGBS adipocytes, and this inhibitory effect was rescued by CPEB1 upregulation. CPEB1 3'-untranslated region was directly targeted by miR-122-5p. CONCLUSION: MiR-122-5p suppresses cytokine expression in SGBS adipocytes by targeting CPEB1.

DNA Vaccines Expressing the Envelope and Membrane Proteins Provide Partial Protection Against SARS-CoV-2 in Mice.

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a public health emergency of international concern, and an effective vaccine is urgently needed to control the pandemic. Envelope (E) and membrane (M) proteins are highly conserved structural proteins among SARS-CoV-2 and SARS-CoV and have been proposed as potential targets for the development of cross-protective vaccines. Here, synthetic DNA vaccines encoding SARS-CoV-2 E/M proteins (called p-SARS-CoV-2-E/M) were developed, and mice were immunised with three doses via intramuscular injection and electroporation. Significant cellular immune responses were elicited, whereas no robust humoral immunity was detected. In addition, novel H-2d-restricted T-cell epitopes were identified. Notably, although no drop in lung tissue virus titre was detected in DNA-vaccinated mice post-challenge with SARS-CoV-2, immunisation with either p-SARS-CoV-2-E or p-SARS-CoV-2-M provided minor protection and co-immunisation with p-SARS-CoV-2-E+M increased protection. Therefore, E/M proteins should be considered as vaccine candidates as they may be valuable in the optimisation of vaccination strategies against COVID-19.

Oxcarbazepine was associated with risks of newly developed hypothyroxinaemia and impaired central set point of thyroid homeostasis in schizophrenia patients.

AIMS: Hypothyroxinaemia might be easily ignored, because attention is typically paid to individuals with elevated thyroid stimulating hormone (TSH). In this study, we aimed to evaluate the association of oxcarbazepine use as adjuvant for treatment of schizophrenia with hypothyroxinaemia and central set point of thyroid homeostasis. METHODS: This retrospective cohort study was conducted in the Second Affiliated Hospital of Xinxiang Medical University. Inpatients with a diagnosis of schizophrenia admitted between January 2016 and October 2019 with normal thyroid function at admission were included. Oxcarbazepine use was the exposure measure. Newly developed hypothyroxinaemia was the primary outcome measure and parameters of thyroid homeostasis central set point as measured by TSH index and thyroid feedback quantile-based index (TFQI) were the secondary outcome measures. RESULTS: In total, 1207 eligible patients were included. The occurrence of hypothyroxinaemia in patients who received oxcarbazepine was higher (35/107, 32.7%) than in those patients who did not (152/1099, 13.8%), with adjusted relative risk of 2.24 and 95% confidence interval of 1.57 and 3.17. Oxcarbazepine use was associated with greater reduction in TSH index (adjusted ß -0.33 and 95% confidence interval -0.48, -0.19) and TFQI (adjusted ß -0.24 and 95% confidence interval -0.31, -0.16). CONCLUSION: Oxcarbazepine use was independently associated with increased risk of developing hypothyroxinaemia, and greater reduction in TSH index and TFQI, suggesting that impaired central set point of thyroid homeostasis might be involved in the mechanism of oxcarbazepine-induced hypothyroxinaemia.

Association between early-onset affective disorders and hypothyroidism in a larger number of psychiatric drug-free patients.

AIMS: We aimed to assess the association between early onset of affective disorders and hypothyroidism in a larger number of psychiatric drug-free patients with bipolar disorder (BD) or major depressive disorder (MDD). METHODS: Early onset of affective disorders was defined as BD and MDD developed before the age of 22 years. The hypothyroidism hierarchy were diagnosed biochemically and included subclinical and overt hypothyroidism in this study. Demographic and clinical data including diagnosis, illness duration and thyroid function parameters (TSH, T4, FT4, T3 and FT3) at admission were collected from patients' records. Adjusted odds ratio (OR) and 95% confidence interval (CI), which were estimated by logistic regression model, were used to assess the association between early-onset affective disorder and hypothyroidism. RESULTS: The prevalence of hypothyroidism in early-onset affective disorders was higher than that in late-onset patients (in BD, 9.4% vs. 6.2%, χ2 = 6.020, P = 0.014; and in MDD 12.7% vs. 6.6%, χ2 = 13.295, P < 0.001). Early-onset affective disorders were 2.097 times (95% CI: 1.409-3.123) more likely to have hypothyroidism compared with late-onset patients, after adjustment for age, gender, duration of illness and mood episode (adjusted OR: 1.965, 95% CI: 1.198-3.221 in BD, and adjusted OR: 2.831, 95% CI: 1.378-5.817 in MDD, respectively). LIMITATION: Because of the cross-sectional design of this study, we were unable to sort out causality between early-onset affective disorders and hypothyroidism. CONCLUSION: Early-onset affective disorder may be associated with higher prevalence of hypothyroidism.

Mediastinal and subglottic hemangioma in an infant: a case report and literature review.

We performed a retrospective analysis of the clinical manifestations, laboratory and imaging examinations, treatment, and prognosis of a male infant who was diagnosed with mediastinal and subglottic hemangioma in our hospital. The clinical features of this patient were coughing, wheezing, and dyspnea. Enhanced computed tomography of the neck and chest showed a diffuse abnormality in the right-upper mediastinum. He was diagnosed with a hemangioma after a physical examination combined with bronchoscopy. The clinical symptoms were relieved by oral propranolol. We also investigated the clinical characteristics, treatment, and prognosis of mediastinal and subglottic hemangioma in infants in the previous literature, and searched for case reports of this disease in China and in other countries. We only identified three previous cases of mediastinal and subglottic hemangioma in infants, indicating that this condition is rare. In the proliferative stage, surrounding organs and tissues are compressed, which can be life-threatening. Most of these children develop wheezing, shortness of breath, dyspnea, cyanosis, and other symptoms within 2 months. Enhanced computed tomography and magnetic resonance imaging combined with soft bronchoscopy can confirm the diagnosis of this disease, and oral propranolol achieves a favorable effect.

Epidemiological investigation of a COVID-19 family cluster outbreak transmitted by a 3-month-old infant.

OBJECTIVE: To investigate the clinical characteristics, epidemiological characteristics, and transmissibility of coronavirus disease 2019 (COVID-19) in a family cluster outbreak transmitted by a 3-month-old confirmed positive infant. METHODS: Field-based epidemiological methods were used to investigate cases and their close contacts. Real-time fluorescent reverse transcription polymerase chain reaction (RT-PCR) was used to detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) for all collected specimens. Serum SARS-CoV-2 IgM and IgG antibodies were detected by Chemiluminescence and Gold immnnochromatography (GICA). RESULTS: The outbreak was a family cluster with an attack rate of 80% (4/5). The first case in this family was a 3-month-old infant. The transmission chain was confirmed from infant to adults (her father, mother and grandmother). Fecal tests for SARS-CoV-2 RNA remained positive for 37 days after the infant was discharged. The infant's grandmother was confirmed to be positive 2 days after the infant was discharged from hospital. Patients A (3-month-old female), B (patient A's father), C (patient A's grandmother), and D (patient A's mother) had positive serum IgG and negative IgM, but patients A's grandfather serum IgG and IgM were negative. CONCLUSION: SARS-CoV-2 has strong transmissibility within family settings and presence of viral RNA in stool raises concern for possible fecal-oral transmission. Hospital follow-up and close contact tracing are necessary for those diagnosed with COVID-19.

Regulation of the Coral-Associated Bacteria and Symbiodiniaceae in Acropora valida Under Ocean Acidification.

Ocean acidification is one of many stressors that coral reef ecosystems are currently contending with. Thus, understanding the response of key symbiotic microbes to ocean acidification is of great significance for understanding the adaptation mechanism and development trend of coral holobionts. Here, high-throughput sequencing technology was employed to investigate the coral-associated bacteria and Symbiodiniaceae of the ecologically important coral Acropora valida exposed to different pH gradients. After 30 days of acclimatization, we set four acidification gradients (pH 8.2, 7.8, 7.4, and 7.2, respectively), and each pH condition was applied for 10 days, with the whole experiment lasting for 70 days. Although the Symbiodiniaceae density decreased significantly, the coral did not appear to be bleached, and the real-time photosynthetic rate did not change significantly, indicating that A. valida has strong tolerance to acidification. Moreover, the Symbiodiniaceae community composition was hardly affected by ocean acidification, with the C1 subclade (Cladocopium goreaui) being dominant among the Symbiodiniaceae dominant types. The relative abundance of the Symbiodiniaceae background types was significantly higher at pH 7.2, indicating that ocean acidification might increase the stability of the community composition by regulating the Symbiodiniaceae rare biosphere. Furthermore, the stable symbiosis between the C1 subclade and coral host may contribute to the stability of the real-time photosynthetic efficiency. Finally, concerning the coral-associated bacteria, the stable symbiosis between Endozoicomonas and coral host is likely to help them adapt to ocean acidification. The significant increase in the relative abundance of Cyanobacteria at pH 7.2 may also compensate for the photosynthesis efficiency of a coral holobiont. In summary, this study suggests that the combined response of key symbiotic microbes helps the whole coral host resist the threats of ocean acidification.

Multi-Omics Revealing the Response Patterns of Symbiotic Microorganisms and Host Metabolism in Scleractinian Coral Pavona minuta to Temperature Stresses.

Global climate change has resulted in large-scale coral reef decline worldwide, for which the ocean warming has paid more attention. Coral is a typical mutually beneficial symbiotic organism with diverse symbiotic microorganisms, which maintain the stability of physiological functions. This study compared the responses of symbiotic microorganisms and host metabolism in a common coral species, Pavona minuta, under indoor simulated thermal and cold temperatures. The results showed that abnormal temperature stresses had unfavorable impact on the phenotypes of corals, resulting in bleaching and color change. The compositions of symbiotic bacteria and dinoflagellate communities only presented tiny changes under temperature stresses. However, some rare symbiotic members have been showed to be significantly influenced by water temperatures. Finally, by using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS) method, we found that different temperature stresses had very different impacts on the metabolism of coral holobiont. The thermal and cold stresses induced the decrease of anti-oxidation metabolites, several monogalactosyldiacylglycerols (MGDGs), and the increase of lipotoxic metabolite, 10-oxo-nonadecanoic acid, in the coral holobiont, respectively. Our study indicated the response patterns of symbiotic microorganisms and host metabolism in coral to the thermal and cold stresses, providing theoretical data for the adaptation and evolution of coral to a different climate in the future.

[Effects of drought on leaf growth and chlorophyll fluorescence kinetics parameters in Cyclobalanopsis glauca seedlings of Karst areas]. / å–€æ–¯ç‰¹å¹²æ—±çŽ¯å¢ƒå¯¹é’å†ˆæ Žå¶ç‰‡ç”Ÿé•¿åŠå¶ç»¿ç´ è§å ‰åŠ¨åŠ›å­¦å‚æ•°çš„å½±å“.

To uncover adaptation mechanism of Cyclobalanopsis glauca to the arid environment of Karst areas, current-year seedlings of C. glauca were potted and grown under four soil water conditions: Normal water supply (-0.1 MPa), light drought stress (-0.5 MPa), moderate drought stress (-0.9 MPa), and severe drought stress (-1.5 MPa). We measured leaf growth and parameters of fast chlorophyll fluorescence induction dynamics after treated by 15, 30, 45, 60 and 90 days. With the increase of drought stress intensity, leaf area, number of green leaves, leaf water content, the contents of chlorophyll a+b and carotenoids, the maximum fluorescence, maximum photochemical quantum yield and potential photochemical efficiency significantly decreased, while the number of dead leaves and the initial fluorescence significantly increased. There was no significant difference in these parameters between light drought and normal water treatments. There were no significant difference in the absorption flux per reaction center (ABS/RC), captured light energy used to restore qA (TRo/RC), number of active reaction centers per unit area (RC/CS), light energy captured per unit area (TRo/CS) and light energy used for electron transfer per unit area (ETo/CS) between light drought and normal water treatments. Among these parameters, RC/CS was slightly higher under light drought treatment than that of normal water treatment. TRo/CS and ETo/CS reached peaks at the 45th day, being 606.12 and 440.78, respectively. Leaf ABS/RC, TRo/RC, ETo/RC, DIRo/RC, RC/CS, TRo/CS and ETo/CS of C. glauca seedlings under mode-rate drought and severe drought treatment were lower than those of normal water treatment, and the parameters under severe drought stress decreased more significantly with the extension of drought stress time. With increasing intensity and duration of drought stress, the maximum quantum efficiency, probability of other electron acceptors, and quantum ratio of electron transfer decreased, but quantum yield for energy dissipation increased. These results demonstrated that C. glauca seedlings under light drought condition showed some degree of adaptability and resistance to drought. Mode-rate drought treatment caused a decline in chlorophyll fluorescence and photosynthetic pigments, leading to slow growth of seedlings. Severe drought had a serious impact on growth of C. glauca seedlings, but did not lead to seedling death. Therefore, C. glauca seedlings showed strong drought tolerance, which were suitable for the application of vegetation restoration and reforestation projects in Karst areas.

Research on pulse response characteristics of wireless ultraviolet communication in mobile scene.

Based on the Riemann sum method, we propose the idea of studying the pulse response width in a moving scene by using the non-line-of-sight (NLOS) wireless ultraviolet (UV) single-scatter communication model. We simulated the effect of the transmitter moving in eight directions from the origin on the pulse response width, when the receiver is fixed at point (100, 0, 0). Furthermore, the pulse response characteristics of the receiver were analyzed with varying elevation angle, beam angle, field-of-view (FOV) angle, and other geometric parameters. The results show that the pulse response width is widened under the condition of movement. In addition, the influence of the elevation angle of the transmitter on the pulse width is larger than that of the receiver. However, the effect of the FOV and beam angles on the pulse response width is not obvious when the FOV angle is large.

Perinatal exposure to di-(2-ethylhexyl) phthalate leads to restricted growth and delayed lung maturation in newborn rats.

BACKGROUND: Pregnant women and infants have significant exposures to the most commonly used plasticizer di-(2-ethylhexyl) phthalate (DEHP). OBJECTIVES: This study was designed to evaluate the effects of DEHP exposure on growth and lung maturation in rats and determine if DEHP regulation of 11beta-hydroxysteroid dehydrogenase type 1 gene (Hsd11b1) expression in the lung tissue plays a role in its effects on lung maturation. METHOD: Pregnant Sprague-Dawley rats were treated from gestational day 12 to postnatal day (PND) 21 with DEHP orally at dosages of 0, 10, 100 or 750 mg/kg/day, respectively (n=8 for each group). Two rat pups (one male and one female) from each litter were sacrificed at PND 1 and 21. Body weight was measured and the lung was processed for histology and calculation of lung interstitial tissue proportion as well as real-time PCR determination of the expressions of Hsd11b1, surfactant associated protein-A1 gene (Sftpa1) and B gene (Sftpb). RESULTS: The perinatal DEHP exposure led to a dose dependent intrauterine and postnatal growth restriction (P<0.001). High dose DEHP (750 mg/kg/day) exposure led to decreased gas-exchange space as evidenced by increased lung interstitial tissue proportion (P<0.001), but did not cause significant changes in Hsd11b1, Sftpa1 or Sftpb gene expression in the rat lung at PND 1. The DEHP-induced change in lung histology remained significant at PND 21 with improvement despite continual exposure to DEHP. CONCLUSION: Perinatal DEHP exposure leads to growth restriction and delayed lung maturation in newborn rats.

[Comparative analysis of the pathogens responsible for hospital acquired and community acquired late onset neonatal septicemia].

OBJECTIVE: Late onset neonatal septicemia (systemic infection after 72 hours of life) remains a major cause of neonatal morbidity and mortality. Early treatment with appropriate antibiotics is critical since infected infants can deteriorate rapidly. The aim of this study was to review the pathogens responsible for late onset neonatal septicemia (LONS) and their antimicrobial susceptibilities in order to guide the initial selection of appropriate antibiotics for infants with suspected LONS. METHODS: A retrospective chart review of all cases with LONS seen in the neonatal intensive care unit (NICU) of Yuying Children's Hospital of Wenzhou Medical College from January 1, 2002 to December 31, 2005 was conducted. All cases were selected based on the clinical presentation and at least one positive result of blood culture. The basic clinical characteristics and the results of blood culture and antimicrobial susceptibilities were analyzed. RESULTS: A total of 102 cases with LONS were identified. Among those 102 cases, 80 were community acquired (infants admitted from home and the blood culture was done on admission) and 22 were hospital acquired (infants became sick while in the NICU and the blood culture was done prior to use of antibiotics). The clinical presentations were non-specific. Compared to the infants with community acquired LONS, infants with hospital acquired LONS were usually born more prematurely (mean gestational age 33 +/- 3 vs 39 +/- 2 wks, t = 2.255, P < 0.01), with lower weight (mean weight 1.79 +/- 0.70 vs 3.23 +/- 0.67 kg, t = 8.818, P < 0.01) and with younger age (mean age 12 +/- 6 vs 16 +/- 7 days, t = 7.581, P < 0.05). Of the 102 cases, a total of 103 strains of bacteria were isolated. Among the pathogenic bacteria isolated, the most common were coagulase-negative Staphylococcus (CoNS) (50/103, 48.5%), followed by Klebsiella pneumoniae (16/103, 15.5%). The main pathogens for community acquired LONS were Staphylococcus species and Escherichia coli. The most important pathogen responsible for hospital acquired LONS was Klebsiella pneumoniae. Most (> 80%) of the Staphylococcus especially CoNS were resistant to common antibiotics such as penicillin, erythromycin and cefazolin. Significant numbers (6/9) of Staphylococcus aureus isolated were methicillin-resistant Staphylococcus aureus (MRSA). However, all of the Staphyloccus isolates were sensitive to vancomycin. Almost all (15/16) of the Klebsiella pneumoniae isolated were multi-drug resistant due to production of extended-spectrum beta-lactamases (ESBLs). They were sensitive only to a few antibiotics such as carbapenems, aminoglycosides and quinolones. There was also one strain of vancomycin-resistant Enterococcus (VRE). Furthermore, there was no a single case of late onset neonatal sepsis due to infection with group B Streptococcus (GBS). CONCLUSIONS: The clinical manifestations of late onset neonatal sepsis are usually non-specific. GBS is not a significant pathogen responsible for community acquired LONS in the Wenzhou area. There are increasing numbers of multi-drug resistant bacterial species isolated from the newborn infants with late onset neonatal septicemia, which is most likely due the non-restricted use of antibiotics in the hospitals as well as in the communities. A routine blood culture should be taken from any newborn infant who is suspected of LONS and empirical use of appropriate antibiotics should be initiated as soon as the blood specimen for culture has been drawn. To reduce the occurrence of multi-drug resistant bacteria, the use of antibiotics especially the third generation cephalosporins in neonates should be restricted as much as possible.