Clinical application of LAMP in rapid detection of pathogens in lower respiratory tract infections / 中国现代医生

@#Objective Loop mediated isothermal amplification(LAMP)was used to detect the distribution of pathogens in sputum samples,namely combined nucleic acid detection of respiratory pathogens(13 pairs),so as to provide provide reference for clinical accurate diagnosis and treatment.Methods A total of 1642 patients with lower respiratory tract infection admitted to Tongren City People's Hospital from January to December in 2022 were selected.Each patient collected sputum specimens/bronchoalveolar for detection by using LAMP(13 pairs).The detection of pathogenic bacteria in respiratory tract and the relationship with sex,age and season were analyzed.Results The overall detection rate of 13 respiratory pathogens was significantly higher in males than in females(P<0.01);In different age groups,the detection rates of Haemophilus influenzae and Streptococcus pneumoniae in patients aged 3-6,Mycoplasma pneumoniae in patients aged 6-18,and methicillin-resistant Staphylococcus aureus,Streptococcus maltophilus,and Klebsiella pneumoniae in patients aged over 60 were significantly higher than those in other groups(P<0.05);In different seasonal groups,Streptococcus pneumoniae and Chlamydia pneumoniae were more prevalent in spring,while Mycoplasma pneumoniae had the highest infection rate in autumn,and the differences were statistically significant(P<0.05).Conclusion LAMP can be used to detect the pathogen rapidly and provide the basis for clinical diagnosis and treatment.

The association of fibrinogen-albumin ratio and neutrophil-lymphocyte ratio with the severity of respiratory syncytial virus infection in children

ABSTRACT Respiratory syncytial virus (RSV) is a common cause of respiratory infections. It is responsible for more than half of lower respiratory tract infections in infants requiring hospitalization. This study aimed to investigate the correlation between the fibrinogen-albumin ratio (FAR) and the severity of RSV infection and to compare its effectiveness with the neutrophil-lymphocyte ratio (NLR). This was a retrospective cohort study with patients aged from 29 days to two years who had been admitted to the pediatric clinic of our hospital. Patients were divided into four groups: group 1 (mild disease), group 2 (moderate disease), group 3 (severe disease), and group 4 (control). FAR and NLR were measured in all groups. FAR was significantly higher in group 3 than in the other groups, in group 2 than in groups 1 and 4, and in group 1 than in group 4 (p<0.001 for all). NLR was significantly higher in group 4 than in the other groups and in group 3 than in groups 1 and 2 (p<0.001 for all). FAR totaled 0.078 ± 0.013 in patients with bronchiolitis; 0.099 ± 0.028, in patients with bronchopneumonia; and 0.126 ± 0.036, in patients with lobar pneumonia, all with statistically significant differences (p<0.001). NLR showed no significant statistical differences. This study found a statistically significant increase in FAR in the group receiving invasive support when compared to that receiving non-invasive support (0.189 ± 0.046 vs. 0.112 ± 0.030; p=0.003). Mechanical ventilation groups showed no differences for NLR. FAR was used to identify severe RSV-positive patients, with a sensitivity of 84.4%, a specificity of 82.2%, and a cutoff value of >0.068. This study determined a cutoff value of ≤1.49 for NLR, with a sensitivity of 62.2% and a specificity of 62.2% to find severe RSV-positive patients. Also, statistically significant associations were found between FAR and hospitalization and treatment length and time up to clinical improvement (p<0.001 for all). NLR and hospitalization and treatment length showed a weak association (p<0.001). In children with RSV infection, FAR could serve to determine disease severity and prognosis and average lengths of hospitalization, treatment, and clinical improvement. Additionally, FAR predicted disease severity more efficiently than NLR.

Distribution and drug resistance of pathogenic bacteria in lower respiratory tract of 276 hospitalized children / 公共卫生与预防医学

Objective To analyze the epidemiological characteristics and drug resistance of pathogenic bacteria in 276 hospitalized children with lower respiratory tract infection to facilitate prevention and treatment. Methods Among of 276 hospitalized children with lower respiratory tract infection from January 2019 to December 2021 were analyzed. Data on the distribution of pathogenic bacteria were collected and analyzed. At the same time, the information on drug resistance was collected, and the potential relationship between pathogen distribution and drug resistance was briefly analyzed and discussed. Results A total of 532 strains of pathogenic bacteria were detected in the blood samples from 276 patients in this study. There were 207 strains of Gram-positive bacteria, including 104 strains of Staphylococcus aureus, 96 strains of Staphylococcus epidermidis and 7 strains of others. Gram negative bacteria (325 strains) were 172 strains of Klebsiella and 153 strains of Escherichia coli. The distribution of pathogenic bacteria in different gender and age groups (under 5 years old, 5-10 years old, and over 10 -14 years old) was calculated separately. The results showed that the distribution of pathogenic bacteria in female children under 5 years old (n=49 cases) was different from the total population: the infection of Gram-positive bacteria was higher than that of Gram-negative bacteria, and the proportion of Staphylococcus epidermidis was the highest (P<0.05). The distribution characteristics of children of other ages and sexes were consistent with the total distribution characteristics. The resistance rate of Gram-positive bacteria to penicillin, erythromycin and clarithromycin was high, while the resistance rate of Gram-negative bacteria to ampicillin, cefazolin and cefuroxime was high. The distribution characteristics were the same in children of different sex and age. Conclusion The pathogenic bacteria in children with lower respiratory tract infection in pediatric ward are mainly Gram-negative bacteria, and the main pathogenic bacteria have a high resistance rate to common drugs. The distribution of pathogenic bacteria in female children under 5 years old is unique: the infection of Gram-positive bacteria is higher than that of Gram-negative bacteria, and the proportion of Staphylococcus epidermidis is the highest, which deserves attention. The clinical drug sensitivity test can be used as an important reference for the treatment of drugs to guide the rational selection of antibiotics.

Epidemiological characteristics and risk factors of rotavirus lower respiratory tract infection in preschool children / 公共卫生与预防医学

Objective To investigate and study epidemiological characteristics and risk factors of rotavirus lower respiratory tract infection in preschool children. Methods The preschool children with rotavirus enteritis and lower respiratory tract infection admitted to the hospital were retrospectively analyzed January 2021 and June 2022. The situations and risk factors of lower respiratory tract infection were evaluated by chest X-ray, serological examination and throat swab culture. Results In the 155 preschool children with rotavirus enteritis, there were 59 (38.06%) cases with lower respiratory tract infection. The results of pathogens culture showed that proportion of Haemophilus influenzae was the highest (28.81%), followed by Streptococcus pneumoniae and Klebsiella pneumoniae (18.64%, 15.25%). There were significant differences between infection group and non-infection group in age, histories of family members smoking, children's aggregated activities and family members' respiratory diseases, family members' and children' attention to hand hygiene, pregnancy outcomes, age at the first usage of antibiotics and onset seasons (P0.05). Logistic regression analysis showed that age <3 years (OR=2.962, P=0.031), history of family members' smoking (OR=2.869, P=0.035), history of family members' respiratory diseases (OR=2.354, P=0.039) and the age at the first usage of antibiotics <1 year (OR=2.622, P=0.033) were all independent risk factors of rotavirus lower respiratory tract infection in preschool children. Conclusion The preschool children with rotavirus are prone to lower respiratory tract infection. Clinically, more attentions should be payed to children with age <3 years, history of family members' smoking, history of family members' respiratory diseases and the age at the first usage of antibiotics <1 year. The targeted measures should be actively taken to prevent the risk of lower respiratory tract infection.

Distribution and antimicrobial resistance pattern of bacteria isolated from alveolar lavage fluid in pediatric patients with lower respiratory tract infection / 中华传染病杂志

Objective:To analyze the distribution and antimicrobial resistance pattern of bacteria isolated from alveolar lavage fluid in pediatric patients with lower respiratory tract infection from 2016 to 2018.Methods:The alveolar lavage fluid of pediatric patients aged <18 years old with lower respiratory tract infection in ten hospitals from January 2016 to December 2018 were collected, and the pathogenic bacteria were cultured and isolated. The paper diffusion method or minimum inhibitory concentration method was used to conduct drug susceptibility tests for the isolated strains.The distribution of pathogenic bacteria and the source department of the strains were analyzed.Chi-sqare test was used for statistical analysis.Results:Of 1 271 isolates, 606 strains (47.7%) were gram-negative bacteria, 628 strains (49.4%) were gram-positive bacteria, and 37 strains (2.9%) were fungi. The common pathogens were Streptococcus pneumoniae (36.7%, 466/1 271), Acinetobacter baumannii (16.8%, 214/1 271), Staphylococcus aureus (12.7%, 162/1 271), Klebsiella pneumoniae (8.3%, 105/1 271), Haemophilus influenzae (7.4%, 94/1 271), Pseudomonas aeruginosa (6.2%, 79/1 271), Burkholderia cepacia (5.3%, 67/1 271) and Escherichia coli (3.7%, 47/1 271). The main pathogens in the intensive care unit (ICU) were gram-negative bacteria (80.1%, 428/534), among which Acinetobacter baumannii was the most common (3.7%, 199/534). The main pathogens in the non-ICU were gram-positive bacteria (70.8%, 522/737). The detection rates of methicillin-resistant Staphylococcus aureus (MRSA) were 45.1%(23/51) in the ICU and 43.2% (48/111) in the non-ICU, respectively. The detection rates of penicillin-resistant Streptococcus pneumoniae (PRSP) were 10.9%(6/55) in the ICU and 18.5% (76/411) in the non-ICU, respectively. The detection rates of carbapenem-resistant Klebsiella pneumoniae (CRKP) were 57.3%(43/75) in the ICU and 33.3%(10/30) in the non-ICU, respectively. The detection rate of carbapenem-resistant Pseudomonas aeruginosa (CRPA) in the ICU was higher than that in the non-ICU (49.1%(27/55) vs 25.0%(6/24)), and the difference was statistically significant ( χ2=3.98, P=0.046). Eight strains (17.0%) of carbapenem-resistant Escherichia coli were detected, and 164 strains(76.6%) of carbapenem-resistant Acinetobacter baumannii were detected. Seventy-eight Haemophilus influenzae isolates were isolated from non-ICU, and the resistance rate to ampicillin was 57.4%(54/94). Burkholderia cepacia isolates were all isolated from ICU, and the resistance rates to piperacillin-tazobactam, levofloxacin, ciprofloxacin and compound sulfamethoxazole were 13.4%(9/67), 3.0%(2/67), 0(0/67) and 9.0%(6/67), respectively. Conclusions:Streptococcus pneumoniae is still the most common pathogen in pediatric patients with lower respiratory tract infection. Gram-negative bacilli are the main pathogens in pediatric patients with lower respiratory tract infection in the ICU. The dection rates of MRSA, PRSP and carbopenem-resistant gram-negative bacilli are high. And the resistance rate of Haemophilus influenzae to ampicillin is also high. The clinical empirical treatment should be determined according to different clinical background.

Epidemiological study of respiratory syncytial virus-associated acute lower respiratory tract infection in hospitalized children in Shanghai / 中华传染病杂志

Objective:To investigate the epidemiological characteristics of hospitalized children with respiratory syncytial virus (RSV)-associated acute lower respiratory tract infection (ALRTI), and to analyzed the risk factors for severe infection.Methods:The epidemiological and clinical data of hospitalized children with ALRTI and positive RSV test from Children′s Hospital of Fudan University from January 2013 to December 2018 were retrospectively analyzed.The hospitalized children from October 2016 to November 2017 were selected by random singular sequence and divided into severe infection group and non-severe infection group. The clinical data of the two groups were compared. Multivariate logistic regression analysis was used to analyze the risk factors of severe RSV-associated ALRTI.Results:A total of 34 192 hospitalized children were diagnosed with ALRTI, and 8 113(23.73%) children were positive for respiratory tract viruses, including 4 028(11.78%) children with RSV infection, which was higher than other common respiratory tract viruses. Among the 4 028 RSV-positive children, 2 550(63.31%) were under six months of age, 3 623(89.95%) were under two years of age. The detection rates of RSV in spring, summer, autumn and winter were 6.47%(553/8 551), 2.46%(176/7 161), 12.85%(1 042/8 111) and 21.77%(2 257/10 369), respectively. In 347 hospitalized children with RSV-associated ALRTI, 54 cases were severe cases. Multivariate logistic regression analysis showed that RSV-positive patients complicated with respiratory diseases ( Z=3.43), cardiovascular diseases ( Z=4.96), non-exclusive breast-feeding ( Z=-1.97) and premature birth ( Z=-1.98) were independent risk factors for severe RSV-associated ALRTI (all P<0.050). Conclusions:RSV is the most important and common viral pathogen in hospitalized children with ALRTI in Shanghai, and infants under six months of age are the most susceptible to RSV. RSV patients complicated with respiratory diseases, cardiovascular diseases, non-exclusive breast-feeding and premature birth are more likely to develope severe RSV-associated ALRTI.

Human bocavirus infection in children hospitalized with lower respiratory tract infections: Does viral load affect disease course?

Objective: To examine the effects of human bocavirus type 1 (HBoV1) on the course of lower respiratory tract infections in cases of monoinfection and coinfection, and the effects of HBoV1 viral load on the disease in children under six years old hospitalized with a diagnosis of HBoV1-associated lower respiratory tract infections. Methods: Children under six years of age, who were hospitalized with the diagnosis of lower respiratory tract infection due to HBoV1 between 1 January 2021 and 1 January 2022 were included in the study. Laboratory confirmation of the respiratory pathogens was performed using polymerase chain reaction (PCR). Results: Fifty-four (16.4%) children with HBoV1 among 329 children whose PCR was positive with bacterial/viral agent in nasopharyngeal swab samples were included in the study. There were 28 (51.9%) males and 26 (48.1%) females with a median age 23.4 months [interquartile range (IQR): 13.2, 30.0 months] (min-max:1 month-68 months). HBoV1 was detected as a monoinfecton in 26 (48.1%) children, and as a coinfection with other respiratory agents in 28 children (51.9%). In multiple regression analysis, coinfection (P=0.032) was associated with the length of hospitalization (P<0.001; R 2 =0.166). There was a negative correlation (r= 0.281, P=0.040) between cough and cycle threshold. Fever was found to be positively correlated with C-reactive protein (r=0.568, P<0.001) and procalcitonin (r=0.472; P=0.001). Conclusions: Although we found a higher HBoV1 viral load in children with more cough symptoms in our study, it had no effect on the severity of the disease, such as length of hospital stay and need for intensive care. Coinfection was found to affect the length of hospitalization.

The effect of recombinant human interferon α1b treatment of infants hospitalized with lower respiratory tract infection on subsequent wheezing

Abstract Objective: To investigate the impact of recombinant human interferon α1b (rhIFNα1b) treatment in infants hospitalized with lower respiratory tract infections on subsequent wheezing. Methods: The clinical data of infants (n = 540) with viral pneumonia, wheezy bronchitis, or bronchiolitis hospitalized in 19 Chinese hospitals from June 2009 to June 2015 were retrospectively analyzed. The parameters relevant to wheezing episodes within the last year were collected by telephone and questionnaires. The rhIFNα1b treatment group (n = 253) and control group (n = 287) were compared in terms of wheezing episodes within the last year. Moreover, the wheezing group (95 cases) and non-wheezing group (445 cases) were compared. Results: Out of 540 cases, 95 (17.6%) experienced wheezing episodes, 13.8% (35/253) cases treated with rhIFNα1b, and 20.9% (60/287) cases without rhIFNα1b experienced wheezing episodes within the last year. The rhIFNα1b treatment significantly improved wheezing episodes within the last year, compared with the control peers (p = 0.031). Single-factor regression showed statistically significant differences between the wheezing and non-wheezing groups in terms of age, rhIFNα1b use, childhood and family history of allergy, housing situation, and feeding history (p < 0.05). Binary logistic regression showed a childhood history of allergy (OR = 2.14, p = 0.004), no rhIFNα1b use (OR = 1.70, p = 0.028), and living in a crowded house (OR = 1.92, p = 0.012) might be risk factors of subsequent wheezing. Accordingly, breastfeeding (OR = 0.44, p = 0.008) and hospitalization age of 1-year-old (OR = 0.58, p = 0.024) were protective factors. Conclusions: Early use of rhIFNα1b in infants hospitalized with lower respiratory tract infections and breastfeeding could prevent subsequent wheezing. Living in a crowded house could promote subsequent wheezing.

Clinical study of acute lower respiratory tract infection caused by respiratory syncytial virus in neonates / 中华实用儿科临床杂志

Objective:To investigate the clinical characteristics of acute lower respiratory tract infection (ALRTI) in neonates caused by respiratory syncytial virus (RSV), and to analyze the factors associated with the severe infection.Methods:Clinical data of 399 ALRTI neonates with positive nucleic acids or antigen of RSV admitted to Shenzhen Children′s Hospital from January 2014 to December 2020 were retrospectively analyzed for their clinical cha-racteristics.They were divided into mild-to-moderate group and severe group according to the severity index (SI), and the clinical data of the 2 groups were compared.Relevant factors of severe ALRTI of RSV in neonates were analyzed by multivariate Logistic regression. Results:(1) A total of 399 ALRTI neonates with RSV infection were included, involving 239 males (59.9%) and 160 females (40.1%) with a male-to-female ratio of 1.49∶1.00.There were 349 cases (87.5%) and 50 cases (12.5%) in the mild-to-moderate group and severe group, respectively.The disease mainly occurred from March to October.(2) There were significant differences in the preterm delivery [15 cases (4.3%) vs.9 cases (18.0%)], low birth weight [11 cases (3.2%) vs.6 cases (12.0%)], previous hospitalization history [12 cases (3.4%) vs.5 cases (10.0%)], and breastfeeding [167 cases (47.9%) vs.16 cases (32.0%)] between the mild-to-moderate group and severe group ( χ2=14.524, 8.394, 4.616 and 4.426, respectively, all P<0.05). (3) There were significant differences in fever [78 cases (22.4%) vs.18 cases (36.0%)], shortness of breath [156 cases (44.7%) vs.36 cases (72.0%)], poor appetite [48 cases (13.8%) vs.15 cases (30.0%)], wheezing [20 cases (5.7%) vs.10 cases (20.0%)], cyanosis [30 cases (8.0%) vs.16 cases (32.0%)] and mental status (irritability/malaise) [20 cases (5.7%) vs.8 cases (16.0%)], and duration of cough[(8.1±2.6) days vs.(9.4±2.9) days ] between the mild-to-moderate group and severe group ( χ2=4.460, 13.057, 8.682, 12.806, 23.486 and 7.068, t=-3.054, all P<0.05). Moist rales in the lungs [29 cases (58.0%) vs.114 cases (32.7%)] and three concave signs [14 cases (28.0%) vs.20 cases (5.7%)] were commonly found in the severe group, while pulmonary phlegm sounds [168 cases (48.1%) vs.14 cases (28.0%)]was commonly found in the mild-to-moderate group, and the differences were statistically significant ( χ2=12.208, 27.823 and 7.149, respectively, all P<0.05). (4) Multifactorial analysis showed that premature delivery was an independent risk factor for the development of severe ALRTI caused by RSV in neonates ( OR=3.717, 95% CI: 1.257-10.987), and shortness of breath ( OR=2.216, 95% CI: 1.061-4.629), cyanosis ( OR=3.621, 95% CI: 1.638-8.004) and three concave signs ( OR=2.688, 95% CI: 1.077-6.711) may be early warning factors for the severe condition. Conclusions:Preterm infants with RSV infection are prone to develop into severe disease, and neonates with RSV infection with shortness of breath, cyanosis and three concave signs as symptoms of severe infection should be well concerned for a close monitoring.

Application of next-generation sequencing technology in pathogen detection of lower respiratory tract infection in children / 中华实用儿科临床杂志

Next-generation sequencing (NGS), also known as high-throughput sequencing, is more efficient compared with Sanger sequencing that has become the standard method of clinical DNA sequencing, and can obtain a large amount of information in a relatively short time at a lower cost.NGS has broad prospects in such aspects as diagnosing the pathogen of lower respiratory tract infection in children, identifying the pathogen of cross-infection in hospital, drug resistance research and vaccine development.It is still worth conducting further studies on the approach to improve the specificity and sensitivity of diagnosis and to optimize NGS.