Analysis of the Current Situation and Risk Factors of Lower Respiratory Tract Infection among ICU Patients in Guizhou,China During 2019-2022

Objective:This study aims to explore the prevalence,features,and risk factors of lower respiratory tract infections(LRTIs)in the intensive care unit(ICU)of a newly established hospital in Zunyi City.The goal is to devise strategies for preventing LRTIs in the ICU of new hospitals,thereby mitigating the incidence of nosocomial LRTIs in ICU patients.Methods:A case-control study was conducted from March 2019 to December 2022 to investigate the incidence rate of LRTIs in the ICU of a newly constructed hospital in Zunyi City.Patients with LRTIs constituted the case group,while those without LRTIs constituted the control group,where a 1:1 matching principle was adhered to.A single-factor chi-square(χ2)test was employed to analyze the risk factors,with independent risk factors being explored using a multivariate logistic regression analysis.Results:A total of 169 strains of pathogenic bacteria were isolated,comprising 66.28%gram-negative bacteria,17.75%gram-positive bacteria,and 15.97%fungi.The most prevalent pathogens included Acinetobacter baumannii(43.20%),Candida albicans(10.65%),and Pseudomonas aeruginosa(8.88%).Of the 82 strains infected by multidrug-resistant bacteria in patients with LRTIs,81.7%were carbapenem-resistant Acinetobacter baumannii,9.8%were multidrug-resistant Pseudomonas aeruginosa,and 6.1%were carbapenem-resistant Escherichia coli.Identified risk factors included smoking history,total hospitalization days,ICU stay length,hypoproteinemia,indwelling gastric tube,intubation type,duration of mechanical ventilation,usage of antibacterial drugs,and administration of protein drugs(P<0.05).Multivariate logistic regression analysis demonstrated that these factors were independent risk factors for nosocomial LRTIs in ICU patients(P<0.05).Conclusion:ICU patients in our hospital were mainly infected by carbapenem-resistant Acinetobacter baumannii.To prevent LRTIs in patients,tailored preventive measures should be developed and the rational use of antibacterial drugs should be promoted.

Respiratory Virus Multiplex RT-PCR Assay Sensitivities and Influence Factors in Hospitalized Children with Lower Respiratory Tract Infections

Multiplex RT-PCR assays have been widely used tools for detection and differentiation of a panel of respiratory viral pathogens. In this study, we evaluated the Qiagen ResPlex lI V2.0 kit and explored factors influencing its sensitivity. Nasopharyngeal swab （NPS） specimens were prospectively collected from pediatric inpatients with lower respiratory tract infections at the time of admission in the Shenzhen Children＇s Hospital from May 2009 to April 2010. Total nucleic acids were extracted using the EZ1 system （Qiagen, Germany） and 17 respiratory viruses and genotypes including influenza A virus （FluA）, FluB, parainfluenza virus 1 （PIV1）, PIV2, PIV3, PIV4, respiratory syncytial virus （RSV）, human metapneumovirus （hMPV）, rhinoviruses （RhV）, enteroviruses （EnV）, human bocaviruses （hBoV）, adenoviruses （AdV）, four coronaviruses （229E, OC43, NL63 and HKU1）, and FluA 2009 pandemic H1NI（H1NI-p） were detected and identified by the ResPlex II kit. In parallel, 16 real-time TaqMan quantitative RT-PCR assays were used to quantitatively detect each virus except for RhV. Influenza and parainfluenza viral cultures were also performed. Among the total 438 NPS specimens collected during the study period, one or more viral pathogens were detected in 274 （62.6%） and 201（45.9%） specimens by monoplex TaqMan RT-PCR and multiplex ResPlex, respectively. When results from monoplex PCR or cell culture were used as the reference standard, the multiplex PCR possessed specificities of 92.9-100.0%. The sensitivity of multiplex PCR for PIV3, hMPV, PIV1 and BoV were 73.1%, 70%, 66.7% and 55.6%, respectively, while low sensitivities （11.1%-40.0%） were observed for FluA, EnV, OC43, RSV and H1N1. Among the seven viruses/genotypes detected with higher frequencies, multiplex PCR sensitivities were correlated significantly with viral loads determined by the TaqMan RT-PCR in FluA, H 1N 1-p and RSV （p=0.011-0.000） The Qiagen ResPlex II multiplex RT-PCR kit possesses excellent specificity for simultaneous detection of 17 viral pathogens in NPS specimens in pediatric inpatients at the time of admission. The sensitivity of multiplex RT-PCR was influenced by viral loads, specimen process methods, primer and probe design and amplification condition.

Prevalence and antimicrobial susceptibility patterns of bacteria in ICU patients with lower respiratory tract infection: A cross-sectional study

Objective: To investigate the prevalence of isolated organisms in patients with lower respiratory tract infections and the antibiotic susceptibilities at a tertiary care center. Methods: In this observational and cross-sectional analysis, 114 patients admitted in the intensive care unit were enrolled. The endotracheal aspirates and bronchoalveolar lavage were collected. The bacteria were isolated and identified, and finally, antimicrobial sensitive pattern of the isolated bacteria was examined. Results: The prevalence of infection was 72.72% in male patients and 27.28% in females. The predominant bacteria were Klebsiella pneumoniae (37.50%) followed by Acinetobacter spp. (36.36%), Pseudomonas aeruginosa (7.95%),Escherichia coli (6.81%), Proteus mirabilis (2.27%), atypical Escherichia coli (1.13%), Enterococcus spp. (1.13%),Elizabethkingia meningoseptica (1.13%),Staphylococcus aureus (1.13%),Proteus vulgaris (1.13%), Citrobacter freundii (1.13%), and Citrobacter koseri (1.13%). High resistance to cephalosporins (82.18%) was demonstrated in all Gram-negative bacteria. Bacteria showed susceptibility to colistin (88.75%) followed by tigecycline (83.11%), gentamycin (36.18%), and amikacin (49.23%). Conclusions: As the most frequent respiratory organisms, Klebsiella pneumoniae and Acinetobacter spp. have increased resistance to cephalosporins and susceptibility to colistin followed by tigecycline.

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.

Association between early viral lower respiratory tract infections and subsequent asthma development

BACKGROUND The association between hospitalization for human respiratory syncytial virus(HRSV)bronchiolitis in early childhood and subsequent asthma is well established.The long-term prognosis for non-bronchiolitis lower respiratory tract infections(LRTI)caused by viruses different from HRSV and rhinovirus,on the other hand,has received less interest.AIM To investigate the relationship between infant LRTI and later asthma and examine the influence of confounding factors.METHODS The PubMed and Global Index Medicus bibliographic databases were used to search for articles published up to October 2021 for this systematic review.We included cohort studies comparing the incidence of asthma between patients with and without LRTI at≤2 years regardless of the virus responsible.The meta-analysis was performed using the random effects model.Sources of heterogeneity were assessed by stratified analyses.RESULTS This review included 15 articles(18 unique studies)that met the inclusion criteria.LRTIs at≤2 years were associated with an increased risk of subsequent asthma up to 20 years[odds ratio(OR)=5.0,95%CI:3.3-7.5],with doctor-diagnosed asthma(OR=5.3,95%CI:3.3-8.6),current asthma(OR=5.4,95%CI:2.7-10.6),and current medication for asthma(OR=1.2,95%CI:0.7-3.9).Our overall estimates were not affected by publication bias(P=0.671),but there was significant heterogeneity[I 2=58.8%(30.6-75.5)].Compared to studies with hospitalized controls without LRTI,those with ambulatory controls had a significantly higher strength of association between LRTIs and subsequent asthma.The strength of the association between LRTIs and later asthma varied significantly by country and age at the time of the interview.The sensitivity analyses including only studies with similar proportions of confounding factors(gender,age at LRTI development,age at interview,gestational age,birth weight,weight,height,smoking exposure,crowding,family history of atopy,and family history of asthma)between cases and controls did not alter the overall estimates.CONCLUSION Regardless of the causative virus and confounding factors,viral LRTIs in children<2 years are associated with an increased risk of developing a subsequent asthma.Parents and pediatricians should be informed of this risk.

Co-expression network analysis of virulence genes exoS and exoU of pseudomonas aeruginosa in lower respiratory tract based on histological data expression profiles

Objective:To use the gene chip of pseudomonas aeruginosa as a research sample and to explore it at an omics level,aiming at elucidating the co-expression network characteristics of the virulence genes exoS and exoU of pseudomonas aeruginosa in the lower respiratory tract from the perspective of molecular biology and identifying its key regulatory genes.Methods:From March 2016 to May 2018,312 patients infected with pseudomonas aeruginosa in the lower respiratory tract who were admitted to Department of Respiratory Medicine of Baogang Hospital and given follow-up treatments in the hospital were selected as subjects by use of cluster sampling.Alveolar lavage fluid and sputum collected from those patients were used as biological specimens.The genes of pseudomonas aeruginosa were detected with the help of oligonucleotide probes to make a pre-processing of chip data.A total of 8 common antibiotics(ceftazidime,gentamicin,piperacillin,amikacin,ciprofloxacin,levofloxacin,doripenem and ticarcillin)against Gram-negative bacteria were selected to determine the drug resistance of biological specimens.MCODE algorithm was used to construct a co-expression network model of the drug-resistance genes focused on exoS/exoU.Results:The expression level of exoS/exoU in the drug-resistance group was significantly higher than that in the non-resistance group(p<0.05).The top 5 differentially expressed genes in the alveolar lavage fluid specimens from the drug-resistance group were RAC1,ITGB1,ITGB5,CRK and IGF1R in the order from high to low.In the sputum specimens,the top 5 differentially expressed genes were RAC1,CRK,IGF1R,ITGB1 and ITGB5.In the alveolar lavage fluid specimens,only RAC1 had a positive correlation with the expression of exoS and exoU(p<0.05).In the sputum specimens,RAC1,ITGB1,ITGB5,CRK and IGF1R were positively correlated with the expression of exoS and exoU(p<0.05).The genes included in the co-expression network contained exoS,exoU,RAC1,ITGB1,ITGB5,CRK,CAMK2D,RHOA,FLNA,IGF1R,TGFBR2 and FOS.Among them,RAC1 had a highest score in the aspect of regulatory ability(72.00)and the largest number of regulatory genes(6);followed by ITGB1,ITGB5 and CRK genes.Conclusions:The high expression of exoS and exoU in the sputum specimens suggests that pseudomonas aeruginosa has a higher probability to get resistant to antibiotics;RAC1,ITGB1,ITGB5 and CRK genes may be the key genes that can regulate the expression of exoS and exoU.

Validation of a Risk-Based Biomarker-Enhanced Scoring System for Lower Respiratory Tract Infections (OPTIMA I Basel)—An Observational Survey

Background: Despiteits recommendation in management guide lines for community acquired pneumonia (CAP), the CURB65 score is frequently not followed for disposition decisions in clinical routine. We therefore proposed an improved CURB65 A score, supplemented by proadre nome dull in (ProADM) levels for patients with CAP and other lower respiratory tract infections (LRTIs). In this study, we vali dated this risk based biomarker enhanced disposition in patients with LRTIs presenting to the emergency department of the University Hospital of Basel. Methods: In this prospective observational cohort study of 85 patients presenting with LRTIs, site of care was decided by the physicians in charge according to their judgement. Retro spectively the CURB65 A score was calculated and a virtual disposition assigned. This was compared with the existing disposition in order to identify efficacy of the novel risk based biomarker enhanced disposition. Results: The novel disposition criteria considered 14 patients suitable for outpatient treatment compared to 11 in the current disposition (p = 0.5). It detected 7 patients to be best treated outside the hospital for nursing reasons, while the current disposition detected only 1 patient requiring geriatric care (p = 0.09). Further, it decreased regular hospitalizations considerably (32 vs. 64, p 0.001). Conclusions: The novel risk based biomarker enhanced disposition is an objective, safe and probably more efficient disposition system to identify outpatient treatment options than the current practice at the University Hospital of Basel.

Assessing the quality of the management skills required for lower respiratory tract infections in Kilimanjaro, Tanzania

Background: Lower respiratory tract infections (LRTI) are among the leading causes of morbidity and mortality. A severe form of atypical pneumonia, Q fever, has been found in Northern Tanzania. Assessment of the quality of health care for lower respiratory tract infection from the clinicians’ performance has rarely been performed. Methods: A cross sectional descriptive study using the qualitative and quantitative approaches for assessing clinicians and patient files from 11 health facilities of Kilimanjaro region. The facilities were of 4 different levels of public health care delivery and 1 private independent hospital. Results: Medications for LRTI were highly variable in 346 files and from attempts of treatment reported in 53 clinician’s interviews. No file showed attempts for assessing the severity of Pneumonia. Only 6 (11.1%) clinicians could mention causes of atypical pneumonia. Only 7 clinicians (13.0%) were aware of Q-fever and could mention the cause. The quality of clinical records for monitoring the progress was not the same in all levels of care and the difference in availability was statistically significant as level of mental state χ2 (4) = 139.4;P

Flu Vaccine Coupled to Vitamin D Decrease the Frequency of Lower Respiratory Tract Infections (Randomized Controlled Trial)

Introduction: Influenza disease is one of the major health concerns in pediatrics. One of the most recently suggested effects of vitamin D is preventing infectious diseases. The aim of our study was to compare flu vaccine effect to flu vaccine associated to vitamin D (100,000 UI per OS) in reducing respiratory tract infections in children. Patients and Methods: 347 healthy children aged 2 to 5 years randomly selected during fall 2012 and the following season fall 2013 were included;upper and lower respiratory tract infections following vaccination were noted. Our results were analyzed using SPSS program (Chi-square and T-test). Results: Out of a total of 347 children included, 150 received flu vaccine and 197 received flu vaccine plus vitamin D. 88 children from both groups manifested upper respiratory tract infections and 64 had lower respiratory tract infections. The statistical analysis revealed no significant difference between the two groups concerning the upper respiratory tract infection (p = 0.207) and a significant difference between groups for the lower respiratory tract infection (p = 0.001). Conclusion: Coupling vitamin D to flu vaccine provides no protection against upper respiratory infections but provides an effective strategy to decrease the rate of lower respiratory infections in children 2 - 5 years of age.

Lung Function in Wheezing Infants after Acute Lower Respiratory Tract Infection and Its Association with Respiratory Outcome

Background： Wheezing is common in early childhood and remains an important health concern. The aim of this study was to assess the lung function of wheezing infants and to investigate the relationship between lung function and respiratory outcome. Methods： Infants 〈2 years of age with acute lower respiratory tract infection （ALRTI） who had undergone lung function tests were included in the study. They were assigned to wheeze or no wheeze group based on physical examination. Infants without any respiratory diseases were enrolled as controls. Lung function was measured during the acute phase and 3 months after ALRTI. One-year follow-up for infants with ALRTI was achieved. Results： A total of 252 infants with ALRTI who had acceptable data regarding tidal breathing were included in the final analysis. Compared with the control and the no wheeze groups, infants in the wheeze group had significantly decreased time to peak tidal expiratory flow as a percentage of total expiratory time （TPTEF/TE） （20.1 1 6.4% vs. 34.4 ± 6.2% and 26.4 ±8.3%, respectively, P 〈 0.0001） and significantly increased peak tidal expiratory flow （PTEF） （90.7 ± 26.3 ml/s vs. 79.3 ± 18.4 ml/s and 86.1 ± 28.0 ml/s, respectively, P 〈 0.01）, sReff and Reff. The infants in the wheeze group still had lower TPTEF/TE and volume to peak tidal expiratory flow as a percentage of total expiratory volume （VPTEF/VE） than the no wheeze infants 3 months after the ALRT1. Moreover, there was a significant inverse relationship between TPTEF/TE, VPTEF/VE, and the recurrence of wheezing and pneumonia. Conclusions： Impaired lung function was present in wheezing infants with ALRTI and the deficits persisted. In addition, the lower level of TPTEF/TE and VPTEF/VE was a risk factor for poor respiratory outcome.

Diagnostic Value of Nasopharyngeal Aspirates in Children with Lower Respiratory Tract Infections

Background： The accuracy of nasopharyngeal aspirate （NPA） specimens in detecting lower respiratory pathogens remains controversial. The objective of this study was to evaluate the diagnostic accuracy of aspirates （NPAs） specimen in lower respiratory tract infections （LRTIs） in children. Methods： The prospective study was designed to collect the data of paired NPAs and bronchoalveolar lavage fluids from children with acute LRTIs from January 2013 to December 2015. All specimens were subjected to pathogen detection： bacterial detection by culture, Mvcoplasma pneumoniae （Mp） detection by polymerase chain reaction assay and virus （influenza A and B viruses, parainfluenza virus [PIV] Types 1 and 3, respiratory syncytial virus, and adenovirus） detection by immunofluorescence assay. The diagnostic accuracy analysis of NPAs was stratified by age ≤3 years （n = 194） and 〉3 years （n = 294）. Results： We collected paired specimens from 488 children. The positive rate of pathogen was 61.6%. For Streptococcus pneumoniae, NPA culture had the specificity of 89.9% and negative predictive value of 100% in age ≤3 years, the specificity of 97.2% and negative predictive value of 98.9% in age 〉3 years. For Mp, the positive predictive values of NPA was 77.4% in children ≤3 years, and 89.1% in children 〉3 years. For PIV III, NPA specimen had the specificity of 99.8% and negative predictive value of 96.5% in children ≤3 years. For adenovirus, NPA had the specificity of 97.8% and negative predictive value of 98.4% in age ≤3 years, the specificity of 98.9% and negative predictive value of 99.3% in age 〉3 years. Conclusions： NPAs are less invasive diagnostic respiratory specimens, a negative NPA result is helpful in ＂rule out＂ lower airway infection; however, a positive result does not reliably ＂rule in＂ the presence of pathogens.

Drug-resistant genes carried by Acinetobacter baumanii isolated from patients with lower respiratory tract infection

Background Acinetobacter baumanii （A. baumanii ） remains an important microbial pathogen resulting in nosocomialacquired infections with significant morbidity and mortality. The mechanism by which nosocomial bacteria, like A. baumanii, attain multidrug resistance to antibiotics is of considerable interest. The aim in this study was to investigate the spread status of antibiotic resistance genes, such as multiple 13-1actamase genes and aminoglycoside-modifying enzyme genes, from A. baumanii strains isolated from patients with lower respiratory tract infections （LRTIs）. Methods Two thousand six hundred and ninety-eight sputum or the bronchoalveolar lavage samples from inpatients with LRTIs were collected in 21 hospitals in the mainland of China from November 2007 to February 2009. All samples were routinely inoculated. The isolated bacterial strains and their susceptibility were analyzed via VITEK-2 expert system. Several kinds of antibiotic resistant genes were further differentiated via polymerase chain reaction and sequencing methods. Results Totally, 39 A. baumanii strains were isolated from 2698 sputum or bronchoalveolar lavage samples. There was not only a high resistant rate of the isolated A. baumanfi strains to ampicillin and first- and second-generation cephalosporins （94.87%, 100% and 97.44%, respectively）, but also to the third-generation cephalosporins （ceftriaxone at 92.31%, ceftazidine at 51.28%） and imipenem （43.59%） as well. The lowest antibiotic resistance rate of 20.51% was found to amikacin. The OXA-23 gene was identified in 17 strains of A. baumanii, and the AmpC gene in 23 strains. The TEM-1 gene was carried in 15 strains. PER-1 and SHV-2 genes were detected in two different strains. Aminoglycoside-modifying enzyme gene aac-3-1a was found in 23 strains, and the aac-6＂lb gene in 19 strains, aac-3-1a and aac-6＂lb genes hibernated in three A. baumanfi strains that showed no drug-resistant phenotype. Conclusions A. baumanii can carry multiple drug-resistant genes at the same time and result in multi-drug resistance. Aminoglycoside-modifying enzyme genes could be hibernating in aminoglycoside sensitive strains without expressing their phenotype.

Significance of Aspergillus spp. isolation from lower respiratory tract samples for the diagnosis and prognosis of invasive pulmonary aspergillosis in chronic obstructive pulmonary disease

Background Chronic obstructive pulmonary diseases （COPD） is an emerging population at risk for invasive infection of Aspergillus. Isolation of Aspergillus from lower respiratory tract （LRT） samples is important for the diagnosis of invasive pulmonary aspergillosis （IPA）. The purpose of this study was to investigate the value of Aspergillus isolation from LRT samples for the diagnosis and prognosis of IPA in COPD population. Methods Clinical record with Aspergillus spp. isolation in COPD and immunocompromised patients was reviewed in a retrospective study. Patients were categorized and compared according to their severity of illness （admitted to general ward or ICU） and immunological function （COPD or immunocompromised）. Results Multivariate statistical analysis showed that, combined with Aspergillus spp. isolation, APACHE II scores 〉18, high cumulative doses of corticosteroids （〉350 mg prednisone or equivalent dose） and more than four kinds of broad-spectrum antibiotics received in hospital may be predictors of IPA in COPD （0R=9.076, P=0.001; 0R=4.073, P=-0.026; OR=4.448, P=-0.021, respectively）. The incidence of IPA, overall mortality, mortality of patients with IPA and mortality of patients with Aspergillus spp. colonization were higher in COPD patients in ICU than in general ward, but were similar between COPD and immunocompromised patients. Conclusions Aspergillus spp. isolation from LRT in COPD may be of similar importance as in immunocompromised patients, and may indicate an increased diagnosis possibility of IPA and worse prognosis when these patients received corticosteroids, antibiotics, and need to admit to ICU. Aspergillus spp. isolation from LRT samples combined with certain risk factors mav be useful in differentiating colonization from IPA and evaluating the prognosis of IPA in COPD patients.

Clinical characteristics and molecular epidemiology of human metapneumovirus in children with acute lower respiratory tract infections in China, 2017 to 2019: A multicentre prospective observational study

Human metapneumovirus(HMPV) infection is one of the leading causes of hospitalization in young children with acute respiratory illness. In this study, we prospectively collected respiratory tract samples from children who were hospitalized with acute lower respiratory tract infection in six hospitals in China from 2017 to 2019. HMPV was detected in 145 out of 2733 samples(5.3%) from the hospitalized children. The majority of HMPV-positive children were under the age of two(67.6%), with a median age of one year. HMPV can independently cause acute lower respiratory tract infection in young children, while all patients showed mild clinical symptoms. Of all the co-infected patients, HMPV was most commonly detected with enterovirus(EV) or rhinovirus(RhV)(38.0%),followed by respiratory syncytial virus(RSV)(32.0%). The highest detection rate occurred from March to May in both northern and southern China. Out of 145 HMPV positive samples, 48 were successfully typed, of which 36strains were subgrouped into subtypes A2c(75%), eight strains were included in subtype B1(16.7%), and four strains were included in subtype B2(8.3%). Moreover, 16 A2c strains contained 111-nucleotide duplications in the G gene. Twenty-seven complete HMPV genomes were successfully obtained, and 25(92.6%) strains belonged to subtype A2c, whereas one strain was included in subgroup B1 and another was included in subgroup B2. A total of 277 mutations were observed in the complete genomes of 25 A2c strains. All results presented here improve our understanding of clinical characteristics and molecular epidemiology of HMPV infection in children.

A multi-center study on Molecular Epidemiology of Human Respiratory Syncytial Virus from Children with Acute Lower Respiratory Tract Infections in the Mainland of China between 2015 and 2019

Human respiratory syncytial virus(RSV) is a major pathogen of acute lower respiratory tract infection among young children. To investigate the prevalence and genetic characteristics of RSV in China, we performed a molecular epidemiological study during 2015–2019. A total of 964 RSV-positive specimens were identified from 5529 enrolled patients during a multi-center study. RSV subgroup A(RSV-A) was the predominant subgroup during this research period except in2016. Totally, 535 sequences of the second hypervariable region(HVR-2) of the G gene were obtained. Combined with182 Chinese sequences from GenBank, phylogenetic trees showed that 521 RSV-A sequences fell in genotypes ON1(512),NA1(6) and GA5(3), respectively;while 196 RSV-B sequences fell in BA9(193) and SAB4(3). ON1 and BA9 were the only genotypes after December 2015. Genotypes ON1 and BA9 can be separated into 10 and 7 lineages, respectively. The HVR-2 of genotype ON1 had six amino acid changes with a frequency more than 10%, while two substitutions H258 Q and H266 L were co-occurrences. The HVR-2 of genotype BA9 had nine amino acid substitutions with a frequency more than10%, while the sequences with T290 I and T312 I were all from 2018 to 2019. One N-glycosylation site at 237 was identified among ON1 sequences, while two N-glycosylation sites(296 and 310) were identified in the 60-nucleotide duplication region of BA9. To conclusion, ON1 and BA9 were the predominant genotypes in China during 2015–2019. For the genotypes ON1 and BA9, the G gene exhibited relatively high diversity and evolved continuously.

Distribution of respiratory viruses which cause lower respiratory tract infection in pediatric age group

Objective:To determine the appropriate treatment regimen and the clinical course of the lower respiratory tract infections(RTIs)and to detect the common viral causes of lower RTIs.Methods:The present study included a total of 255 pediatric patients aged less than 7 years old and admitted to the Department of Pediatrics of Rize Training and Research Hospital between January 2014 and January 2015 with clinical pre-diagnosis of lower RTI.Nasopharyngeal swab specimens collected from these patients were tested for viral pathogens by using multiplex RTPCR kit the ResPlex II plus Panel PRE(Qiagen,Germany).Results:A total of 212 out of 255(83.1%)specimens revealed positive for one or more viral pathogens.The most common detected pathogens were respiratory syncytial virus(RSV)A/B in 110 samples(43.1%),rhinovirus in 51 samples(20.0%),adenovirus in 36 samples(14.1%),influenzae virus A in 32 samples(12.5%),and coronavirus in 24 samples(9.4%).In 76 samples(29.8%),more than one viral pathogen were detected.RSV was seen in more than 50%patients in the first 2 years.RSV was the most common pathogen in each year of the first 5 years but rhinovirus,influenza A and adenovirus were seen more than RSV after the fifth year.A total of 95.8%of the viral detections were seen between November and April without a significant peak amongst these months.The distribution of the pathogens by months of the year showed no significance.Conclusions:These findings can contribute to epidemiological data of Turkey.Detection of the viral pathogens causing lower RTIs can be critical in management of the disease,decrease inappropriate antibiotic treatment,and lower the morbidity and mortality rates in such diseases.

Gene typing and antibiotic resistance of methicillin- resistant Staphylococcus aureus isolated from lower respiratory tract at two hospitals in Shanghai

Objective To study the genotyping characteristics and antibiotic resistance of methicillin-resistant Staphylococcus aureus(MRSA)isolated from lower respiratory tract at 2 different level hospitals in Shanghai.Methods The subjects included 155 patients at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014,including 108 males and 47 females,with a mean age

Pharmacokinetic-pharmacodynamic analysis of ciprofloxacin in elderly Chinese patients with lower respiratory tract infections caused by Gram-negative bacteria

Background: Ciprofloxacin is usually used in the treatment of lower respiratory tract infections (LRTIs). Recent studies abroad shown ciprofloxacin is inadequately dosed and might lead to worse outcomes. The aim of this study was to perform pharmacokinetic and pharmacodynamic analyses of ciprofloxacin in elderly Chinese patients with severe LRTIs caused by Gramnegative bacteria. Methods: From September 2012 to June 2014, as many as 33 patients were empirically administered beta-lactam and ciprofloxacin combination therapy. Patients were infused with 200 or 400 mg of ciprofloxacin every 12 h, which was determined empirically by the attending physician based on the severity of the LRTI and the patienfs renal condition. Ciprofloxacin serum concentrations were determined by high-performance liquid chromatography. Bacterial culture was performed from sputum samples and/or endotracheal aspirates, and the minimum inhibitory concentrations (MICs) of ciprofloxacin were determined. The ratios of the area under the serum concentration-time curve to the MIC (AUC/MIC) and of the maximum serum concentration of the drug to the MIC (Cmax/MIC) were calculated. The baseline data and pharmacokinetic parameters were compared between clinical success group and clinical failure group, bacteriologic success group and bacteriologic failure group. Results: Among the 33 patients enrolled in the study, 17 were infected with Pseudomonas aeruginosa, 14 were infected with Acinetobacter baumannii^ and two were infected with Klebsiella pneumoniae. The mean age of the patients was 76.9 土 6.7 years. Thirty-one patients (93.4%) did not reach the target AUC/MIC value of >125, and 29 patients (87.9%) did not reach the target Cmax/MIC value of >8. The AUC/MIC and Cniax/MIC ratios in the clinical success group were significantly higher than those in the clinical failure group (61.1 [31.7-214.9] vs. 10.4 [3.8-66.1], Z =-4.157;9.6 [4.2-17.8] vs, 1.3 [0.4-4.7], Z =-4.018;both P< 0.001). The AUC/MIC and Cmax/MIC ratios in the patients for whom the pathogens were eradicated were significantly higher than those in the patients without the pathogens eradicated (75.3 [31.7-214.9] vs. 10.5 [3.8-66.1], Z =—3.938;11.4 [4.2-17.8] vs. 1.4 [0.4-5.4], Z =—3.793;P < 0.001 for both). Receiver operating characteristic curve analysis showed that the AUC/MIC and Cmax/ MIC values were closely associated with clinical and bacteriologic efficacies (P<0.001 in both). Conclusions: Ciprofloxacin is inadequately dosed against Gram-negative bacteria, especially for those with relatively high MIC values. Consequently, the target values, AUC/MIC > 125 and Cmax/MIC> 8, cannot be reached.

肺泡灌洗液mNGS检测神经外科重症下呼吸道感染病原的应用

目的分析宏基因二代测序(mNGS)技术对神经外科重症下呼吸道感染患者肺泡灌洗液中病原体和肺炎克雷伯菌耐药基因检测。方法选取2020年6月至2022年6月河南省人民医院收治的196例神经外科重症下呼吸道感染患者作为研究对象。采集患者的肺泡灌洗液标本进行常规病原学与mNGS技术检测,对病原体进行分离鉴定,并计算2种检测方法的差异性;并检测肺炎克雷伯菌的耐药基因与药敏试验结果。结果常规病原学检测的阳性率为62.42%(122/196),mNGS技术检测阳性率为88.27%(173/196),mNGS技术检测高于常规病原学检测(χ^(2)=35.631,P<0.05);肺炎克雷伯菌经mNGS技术检出耐药基因包括超广谱β-内酰胺酶基因(SHV、TEM)与碳青霉烯酶基因(KPC);药敏试验结果显示,肺炎克雷伯菌对头孢唑林、头孢呋辛及头孢曲松的耐药率较高,分别为75.00%、66.67%及54.17%,对比阿培南及美罗培南的耐药率较低,分别为16.67%及12.50%。结论mNGS技术能够有效提高神经外科重症下呼吸道感染阳性检出率,可辅助评估肺炎克雷伯菌抗菌药物耐药性基因。

呼出气一氧化氮、肺泡一氧化氮和嗜酸性粒细胞对3~6岁儿童呼吸系统疾病的鉴别诊断价值

目的探讨呼出气一氧化氮(FeNO)、肺泡一氧化氮(CaNO)和嗜酸性粒细胞(EOS)在甘肃省兰州市3~6岁儿童呼吸系统疾病鉴别诊断中的应用价值。方法选取确诊哮喘或过敏性鼻炎或下呼吸道感染的360例3~6岁儿童作为研究对象,采用斯皮尔曼秩相关系数评估FeNO、CaNO、EOS的相关性,通过随机森林模型、受试者工作特征(ROC)曲线、多因素逻辑回归分析评估FeNO、CaNO和EOS对3种疾病的鉴别诊断价值。结果哮喘患儿的FeNO、CaNO中位数高于其他疾病患儿,过敏性鼻炎患儿的EOS中位数最低,下呼吸道感染患儿的FeNO、CaNO中位数最低。相关性分析结果显示,FeNO与CaNO呈正相关(r=0.59,P<0.05),FeNO与EOS呈负相关(r=-0.61,P<0.05),CaNO与EOS呈负相关(r=-0.63,P<0.05)。随机森林模型显示,FeNO在疾病分类中的重要性最高。ROC曲线分析结果显示,3种疾病中,FeNO、CaNO、EOS对下呼吸道感染的诊断效能均最高(曲线下面积分别为0.86、0.91、1.00)。多因素逻辑回归模型诊断哮喘的曲线下面积为0.96,灵敏度为0.902,特异度为0.881。结论FeNO、CaNO和EOS在鉴别诊断兰州地区3~6岁儿童哮喘、过敏性鼻炎、下呼吸道感染方面展现出较好的潜力,且基于三者构建的多因素逻辑回归模型可有效提升对哮喘的诊断准确性。