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.

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.

[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.

[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.