Community-acquired Lower Respiratory Infections Research Articles

Syndromic testing for respiratory pathogens but not National Early Warning Score can be used to identify viral cause in hospitalised adults with lower respiratory tract infections

Background Community-acquired lower respiratory tract infection (LRTI) is a common reason for hospitalisation. Antibiotics are frequently used while diagnostic microbiological methods are underutilised in the acute setting. Objectives We aimed to investigate the relative proportion of viral and bacterial infections in this patient group and explore methods for proper targeting of antimicrobial therapy. Methods We collected nasopharyngeal samples prospectively from adults hospitalised with LRTIs during three consecutive winter seasons (2016–2019). Syndromic nasopharyngeal testing was performed using a multiplex PCR panel including 16 viruses and four bacteria. Medical records were reviewed for clinical data. Results Out of 220 included patients, a viral pathogen was detected in 74 (34%), a bacterial pathogen in 63 (39%), both viral and bacterial pathogens in 49 (22%), while the aetiology remained unknown in 34 (15%) cases. The proportion of infections with an identified pathogen increased from 38% to 85% when syndromic testing was added to standard-of-care testing. Viral infections were associated with a low CRP level and absence of pulmonary infiltrates. A high National Early Warning Score did not predict bacterial infections. Conclusions Syndromic testing by a multiplex PCR panel identified a viral infection or viral/bacterial coinfection in a majority of hospitalised adult patients with community-acquired LRTIs.

Study protocol: infectious diseases consortium (I3D) for study on integrated and innovative approaches for management of respiratory infections: respiratory infections research and outcome study (RESPIRO)

BackgroundCommunity-acquired respiratory infections are a leading cause of illness and death globally. The aetiologies of community-acquired pneumonia remain poorly defined. The RESPIRO study is an ongoing prospective observational cohort study aimed at developing pragmatic logistical and analytic platforms to accurately identify the causes of moderate-to-severe community-acquired pneumonia in adults and understand the factors influencing disease caused by individual pathogens. The study is currently underway in Singapore and has plans for expansion into the broader region.MethodsRESPIRO is being conducted at three major tertiary hospitals in Singapore. Adults hospitalised with acute community-acquired pneumonia or lower respiratory tract infections, based on established clinical, laboratory and radiological criteria, will be recruited. Over the course of the illness, clinical data and biological samples will be collected longitudinally and stored in a biorepository for future analysis.DiscussionThe RESPIRO study is designed to be hypothesis generating, complementary to and easily integrated with other research projects and clinical trials. The detailed clinical database and biorepository will yield insights into the epidemiology and outcomes of community-acquired lower respiratory tract infections in Singapore and the surrounding region and offers the opportunity to deeply characterise the microbiology and immunopathology of community-acquired pneumonia.

Mycoplasma Pneumoniae as a Causative Agent of Community-Acquired Lower Respiratory Tract Infections in Children

Mycoplasma pneumoniae (M. pneumoniae) causes respiratory tract infections in all age groups but older children and young adults are more affected than other age groups.

Changes in the levels of WBC count, PCT, CRP and ESR in Patients with acute Community-acquired Lower Respiratory tract infections and their diagnostic value.

To investigate the levels of white blood cell count (WBC), procalcitonin (PCT), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in patients with acute community-acquired lower respiratory tract infections and the value of their combined detection in predicting the occurrence of complications. A retrospective analysis was conducted on the clinical data of 218 patients with acute community-acquired lower respiratory tract infections admitted to Baoding No.1 Central Hospital from January 2021 to December 2021. All patients were divided into two groups according to the presence of complications during treatment: the group with complications (observation group) and the group without complications (control group). The treatment situation of the two groups was compared, and their levels of WBC, PCT, CRP and ESR were quantitatively detected and compared. Patients in the observation group were hospitalized for significantly longer days than those in the control group (P<0.05), and their combined pleural effusion percentage and oxygen uptake rate were higher than those in the control group (P<0.05). The levels of WBC, PCT, CRP and ESR in the observation group were significantly higher than those in the control group at admission, with statistically significant differences (P<0.05). Moreover, the positive rates of WBC, PCT, CRP and ESR in the observation group were higher than those in the control group in the single detection and the combined detection (P<0.05). The combined detection of WBC, PCT, CRP and ESR has substantial predictive value in predicting the occurrence of complications in patients with community-acquired lower respiratory tract infections.

Predicting adverse outcomes in adults with a community-acquired lower respiratory tract infection: a protocol for the development and validation of two prediction models for (i) all-cause hospitalisation and mortality and (ii) cardiovascular outcomes

BackgroundCommunity-acquired lower respiratory tract infections (LRTI) are common in primary care and patients at particular risk of adverse outcomes, e.g., hospitalisation and mortality, are challenging to identify. LRTIs are also linked to an increased incidence of cardiovascular diseases (CVD) following the initial infection, whereas concurrent CVD might negatively impact overall prognosis in LRTI patients. Accurate risk prediction of adverse outcomes in LRTI patients, while considering the interplay with CVD, can aid general practitioners (GP) in the clinical decision-making process, and may allow for early detection of deterioration. This paper therefore presents the design of the development and external validation of two models for predicting individual risk of all-cause hospitalisation or mortality (model 1) and short-term incidence of CVD (model 2) in adults presenting to primary care with LRTI.MethodsBoth models will be developed using linked routine electronic health records (EHR) data from Dutch primary and secondary care, and the mortality registry. Adults aged ≥ 40 years with a GP-diagnosis of LRTI between 2016 and 2019 are eligible for inclusion. Relevant patient demographics, medical history, medication use, presenting signs and symptoms, and vital and laboratory measurements will be considered as candidate predictors. Outcomes of interest include 30-day all-cause hospitalisation or mortality (model 1) and 90-day CVD (model 2). Multivariable elastic net regression techniques will be used for model development. During the modelling process, the incremental predictive value of CVD for hospitalisation or all-cause mortality (model 1) will also be assessed. The models will be validated through internal-external cross-validation and external validation in an equivalent cohort of primary care LRTI patients.DiscussionImplementation of currently available prediction models for primary care LRTI patients is hampered by limited assessment of model performance. While considering the role of CVD in LRTI prognosis, we aim to develop and externally validate two models that predict clinically relevant outcomes to aid GPs in clinical decision-making. Challenges that we anticipate include the possibility of low event rates and common problems related to the use of EHR data, such as candidate predictor measurement and missingness, how best to retrieve information from free text fields, and potential misclassification of outcome events.

Routine Metagenomics Service for ICU Patients with Respiratory Infection.

Rationale: Respiratory metagenomics (RMg) needs evaluation in a pilot service setting to determine utility and inform implementation into routine clinical practice. Objectives: Feasibility, performance, and clinical impacts on antimicrobial prescribing and infection control were recorded during a pilot RMg service. Methods: RMg was performed on 128 samples from 87 patients with suspected lower respiratory tract infection (LRTI) on two general and one specialist respiratory ICUs at Guy's and St Thomas' NHS Foundation Trust, London. Measurements and Main Results: During the first 15 weeks, RMg provided same-day results for 110 samples (86%), with a median turnaround time of 6.7 hours (interquartile range = 6.1-7.5 h). RMg was 93% sensitive and 81% specific for clinically relevant pathogens compared with routine testing. Forty-eight percent of RMg results informed antimicrobial prescribing changes (22% escalation; 26% deescalation) with escalation based on speciation in 20 out of 24 cases and detection of acquired-resistance genes in 4 out of 24 cases. Fastidious or unexpected organisms were reported in 21 samples, including anaerobes (n = 12), Mycobacterium tuberculosis, Tropheryma whipplei, cytomegalovirus, and Legionella pneumophila ST1326, which was subsequently isolated from the bedside water outlet. Application to consecutive severe community-acquired LRTI cases identified Staphylococcus aureus (two with SCCmec and three with luk F/S virulence determinants), Streptococcus pyogenes (emm1-M1uk clone), S. dysgalactiae subspecies equisimilis (STG62647A), and Aspergillus fumigatus with multiple treatments and public health impacts. Conclusions: This pilot study illustrates the potential of RMg testing to provide benefits for antimicrobial treatment, infection control, and public health when provided in a real-world critical care setting. Multicenter studies are now required to inform future translation into routine service.

Detection of Macrolide Resistant Mycoplasma pneumoniae in Children with Lower Respiratory Tract Infection by Sanger Sequencing Targeting Domain V Region of 23S rRNA Gene

Mycoplasma pneumoniae is recognized as the leading cause of community-acquired lower respiratory tract infection in children, accounting for a significant proportion of pediatric mortality. Macrolides are the first-line treatment for M. pneumoniae infections. However, the extensive use of macrolides in clinical practice resulted in the emergence of macrolide-resistant M. pneumoniae (MRMP), which has a negative impact on treatment outcomes. Hence, in the present study, MRMP was determined in hospitalized children with community-acquired pneumonia (CAP). Real-time PCR detected M. pneumoniae in 41 of 348 clinical samples. Sanger sequencing revealed that none of the isolates were associated with the A2063G or A2064G base mutation, which confers macrolide resistance, in domain V of the 23S rRNA gene. Although MRMP was not observed in children with CAP in our study, healthcare practitioners should be vigilant about the potential risk of MRMP infections.

Gram Stain and Culture of Sputum Samples Detect Only Few Pathogens in Community-Acquired Lower Respiratory Tract Infections: Secondary Analysis of a Randomized Controlled Trial.

Identification of the bacterial etiology of lower respiratory tract infections (LRTI) is crucial to ensure a narrow-spectrum, targeted antibiotic treatment. However, Gram stain and culture results are often difficult to interpret as they depend strongly on sputum sample quality. We aimed to investigate the diagnostic yield of Gram stain and culture from respiratory samples collected by tracheal suction and expiratory technique from adults admitted with suspected community-acquired LRTI (CA-LRTI). In this secondary analysis of a randomized controlled trial, 177 (62%) samples were collected by tracheal suction, and 108 (38%) by expiratory technique. We detected few pathogenic microorganisms, and regardless of sputum quality, there were no significant differences between the sample types. Common pathogens of CA-LRTI were identified by culture in 19 (7%) samples, with a significant difference between patients with or without prior antibiotic treatment (p = 0.007). The clinical value of sputum Gram stain and culture in CA-LRTI is therefore questionable, especially in patients treated with antibiotics.

Retrospective Analysis of the Safety of Antibacterial Medicinal Products for Elderly Patients with Community-Acquired Lower Respiratory Tract Infections

Cephalosporins are the empirical antibiotic therapy (ABT) of choice for patients with community-acquired pneumonia (CAP). When treated with antibiotics, elderly patients, especially those with comorbidities, are at higher risk of developing adverse drug reactions (ADRs). The aim of the study was to analyse data on the safety and efficacy of initial empirical ABT with cephalosporins in elderly patients over 75 years old with CAP admitted to multidisciplinary hospitals in Moscow. Materials and methods . The retrospective study included 305 medical records of patients with CAP admitted to three multidisciplinary hospitals in Moscow in 2017–2019 and prescribed initial mono- and/or combination ABT including a cephalosporin. Initial ABT was considered effective if the body temperature normalised within 48–72 h from the start of treatment. It was considered safe if there were no ADRs during hospital stay. Results . Mostly, patients were prescribed ceftriaxone monotherapy or ceftriaxone and azithromycin combination therapy. These ABT regimens were effective in 69.07% and 78.10% of the cases, respectively. Patients with severe CAP needed their initial ABT adjusted significantly more often than those with non-severe CAP. The initial ABT was changed for a number of reasons, including ineffectiveness, ADRs, abscesses formed as a complication of CAP, sputum culture results enabling causal ABT, secondary hospital-acquired infections, and exacerbated chronic infections. All patients had comorbidities, and the most prevalent were arterial hypertension (83.9%), coronary heart disease (45.6%), chronic heart failure (44.9%), cerebrovascular disease (40.9%), atrial fibrillation (26.9%), diabetes mellitus (21.3%), and chronic obstructive pulmonary disease (19.0%). Initial ABT was significantly more often considered ineffective in patients with chronic heart failure and cerebrovascular disease. The most common causative agent of CAP in the study population was Streptococcus pneumoniae (31.9%). In 16% of patients, the authors identified ADRs associated with the antibiotics used as initial therapy. The most common were diarrhoea, anaemia, leucopenia, and hepatopathy. Ceftriaxone was associated with ADRs in 11% of patients. Conclusions . The study results suggest that initial mono- and/or combination ABT including a cephalosporin is effective and relatively safe; therefore, this treatment option is expedient for elderly patients with CAP. For this population, the safety of ABT may be improved through the wider use of existing markers of ADRs and the identification of new ones.

Role of procalcitonin in diagnosis of community acquired pneumonia in Children

BackgroundThe role of serum Procalcitonin (PCT) in adults in diagnosis of Community acquired pneumonia (CAP) is well established, however, role in pediatric CAP remains controversial.ObjectivesThe objective of this study was to investigate the utility of serum procalcitonin in differentiating bacterial community-acquired lower respiratory tract infection from non-bacterial respiratory infection in children; radiologically confirmed pneumonia was used as the reference. In addition, we assessed the utility of adding the PCT assay to the clinical criteria for diagnosis of pneumonia.Study designSubanalysis of a larger prospective,multicentriccohort study.ParticipantsChildren, 2 months to 59 months of age, attending paediatric OPD of 5 urban tertiary care hospitals, suffering from acute respiratory infection (ARI).InterventionDetailed clinical history and examination findings of enrolled children were recorded on predesigned case record form. Samples for PCT were obtained at admission and were measured centrally at the end of the study except for one site using VIDAS® B.R.A.H.M.S PCT kit (Biomerieux SA, France).OutcomesSensitivity and specificity of procalcitonin for diagnosis of radiologically confirmed pneumonia.ResultsSerum Procalcitonin was measured in 370 patients; median (IQR) age of these children being 12 (7, 22) months, 235 (63.5%) were boys. The median (IQR) serum procalcitonin concentration was 0.1(0.05, 0.4) ng/mL.Sensitivity and specificity of raised PCT (> 0.5 ng/mL) for pneumonia as per any CXR abnormalities were 29.7% and87.5%,(P < 0.001) respectively. Raised PCT was also significantly associated with consolidation (34.5%,79.2%,P < 0.02)and pleural effusion(54.6%,79%,P < 001). Adding PCT to the existing clinical criteria of WHO did not improve the sensitivity for diagnosis of pneumonia. PCT was significantly higher in children with severe pneumonia.ConclusionPositive PCT (> 0.5 ng/mL) is significantly associated with radiographic pneumonia but not with pneumonia based on WHO criteria.However, it can act as a surrogate marker for severe pneumonia.

Detection of Mycoplasma pneumoniae by two polymerase chain reactions and role of Mycoplasma pneumoniae in pediatric community–acquired lower respiratory tract infections

PurposeThe study was conducted to evaluate the role of Mycoplasma pneumoniae (M. pneumoniae) in children with community-acquired lower respiratory tract infections (LRTIs). MethodsSeventy five children aged 2 months −12 years with community-acquired LRTIs were investigated for M. pneumoniae etiology employing paired serum samples to assay M. pneumoniae antibodies. Nasopharyngeal aspirates were obtained for the detection of M. pneumoniae by using polymerase chain reaction(PCR) and nested PCR. ResultsM. pneumoniae infection was positive in 24(85.71%) children aged <5 years and 4 (14.29%) ​≥ ​5–12 years and the difference was statistically insignificant (P ​= ​0.18). Difference in prevalence of M. pneumoniae infection across male and female groups was statistically insignificant (P ​= ​0.69). Clinical and radiological profiles across M. pneumoniae positive and negative cases were comparable except bronchopneumonia which was statistically significant (P ​= ​0.04). Serological evidence of M. pneumoniae infection was observed in 26(33%); PCR was positive in 9 (12%) and nested PCR in 10 (13.33%) children. Together, serology, PCR and nested PCR diagnosed M. pneumoniae infection in 28(37.33%) patients. Sensitivity of serology was 77.78%: specificity 68.18%; positive predictive value 25.00% and negative predictive value at 95.74%. ConclusionsSerological and molecular methods in combination is useful for detection of M. pneumoniae. Our data underline the role of M. pneumoniae in community-acquired LRTIs in children of all ages.

155. In Vitro Evaluation of Delafloxacin Activity Against Contemporary US Isolates from Community-Acquired Pneumonia and Community-Acquired Lower Respiratory Tract Infections: Results from the SENTRY Antimicrobial Surveillance Program (2014-2020)

155. <i>In Vitro</i> Evaluation of Delafloxacin Activity Against Contemporary US Isolates from Community-Acquired Pneumonia and Community-Acquired Lower Respiratory Tract Infections: Results from the SENTRY Antimicrobial Surveillance Program (2014-2020)

Community-acquired lower respiratory tract infections in an adult population with HIV infection in a Nigerian tertiary hospital

Objective: Lower respiratory tract infections (LRTI) are 25-fold more common in people with HIV than in the general population. This study aimed to determine the prevalence of community-acquired LRTI and its associated factors in an adult population of people living with HIV (PLWH) in a Nigerian tertiary Hospital.Methodology: This was a prospective study done at the HIV clinic of Ladoke Akintola University of Technology (LAUTECH) Teaching Hospital Osogbo, Nigeria. It involved 130 randomly selected adult participants with a confirmed HIV-positive serology. The participants were followed up for a period of one year while looking out for symptoms and signs suggestive of LRTI.Results: The participants had a mean age of 41.9±10.02 years and a male to female ratio of 0.4:1. Seventeen (13.9%) of the participants developed LRTI during the study period and this was significantly associated with CD4 count and cigarette smoking history.Conclusion: LRTI is common among PLWH in Osogbo, and it occurs more commonly in those with low CD4 Tcell count and those with a history of cigarette smoking.&#x0D; Keywords: Lower respiratory tract infection, HIV, pneumonia.

СУЧАСНІ МЕТОДИ ЕТІОЛОГІЧНОЇ ДІАГНОСТИКИ ГОСТРИХ НЕГОСПІТАЛЬНИХ ІНФЕКЦІЙ НИЖНІХ ДИХАЛЬНИХ ШЛЯХІВ

MODERN METHODS OF ETIOLOGICAL DIAGNOSING OF ACUTE COMMUNITY-ACQUIRED LOWER RESPIRATORY TRACT INFECTIONS O. L. Bororova, Y. O. Dziublyk, V.A. Iachnyk Abstract The review presents the possibilities presented by various methods of etiological diagnostics used in pulmonology. The main method of diagnosing acute community-aquired lower respiratory tract infections is the microbiological approach which includes microscopy of patient’s material with Gram staining, cultures on nutrient media, isolation of culture, identification and determination of susceptibility of a microorganism to antibiotics. But unfortunately the etiologocal factor cannot be detected in about half of patients. Recently, the popularity of molecular methods of etiological diagnosis has grown. They are characterized by greater sensitivity to microbiological methods and allow to get results faster. Molecular diagnostic tests are divided into four categories depending on the mechanism based on them: immunoassay, hybridization methods, amplification and sequencing methods. Among the tests based on the principles of immunoassay, noteworthy are rapid tests, which are most consistent with the idea of an ideal diagnostic tool in the field of laboratory medicine. They are fast, simple, cheap, highly sensitive and highly specific. However, as the appearance of specific antibodies in the body takes some time, the results of tests based on immunoassay remain positive for several weeks after the delayed episode of acute community-acquired lower respiratory tract infection, so they have diagnostic value only in the presence of clinical manifestations of the disease. The genetic approach allows the detection of infectious agents in the early stages of the disease, when serological and immunological methods are ineffective. Tests based on nucleic acid amplification, including PCR, have also become increasingly common recently. These methods should be used for the diagnosis of atypical pathogens and respiratory viruses, because their cultivation in culture is difficult. Sequencing and mass spectrometry methods are being actively developed, but there are limitations that prevent their use in everyday clinical practice. So the combination of microbiological approach with molecular diagnostic methods is the most optimal for the identification of the causative agent of acute community-acquired lower respiratory tract infections and the use of targeted etiotropic treatment. Key words: acute community-acquired lower respiratory tract infections, etiological diagnosis, microbiological, serological, immunological, molecular genetic methods, ICA, PCR, sequencing, mass spectrometry. Ukr. Pulmonol. J. 2021;29(3):58–65

Левофлоксацин в лечении внебольничных инфекций нижних дыхательных путей: взгляд через четверть века

This review is devoted to the 25th anniversary of the beginning of the widespread use of the prototype of “respiratory” fluoroquinolones levofloxacin in clinical practice. The article presents the evidence of clinical and microbiological efficacy, as well as good tolerability of levofloxacin obtained during numerous clinical studies, as well as evidence of long-term successful use of the antibiotic in real clinical practice, which determines its unique place in modern schemes of antibacterial therapy of adult patients with community-acquired lower respiratory tract infections.

Pharmacokinetics and pharmacodynamics of levofloxacin in bronchial mucosa and lung tissue of patients undergoing pulmonary operation.

Levofloxacin is a major antimicrobial agent that is used for the treatment of community-acquired lower respiratory tract infections (LRTIs). The present study was designed to investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of levofloxacin in bronchial mucosa and lung tissue. A total of 32 patients undergoing pulmonary surgery were randomly assigned to one of four groups (8 subjects/group). All patients received a single dose of 500 mg levofloxacin orally prior to the operation. Blood, lung tissue and bronchial mucosa samples were collected prior to treatment and at 1.5, 4, 8, 12 and 24 h following treatment. The drug concentration was determined and PK and PD profiles were calculated using MATLAB software. The peak concentration of levofloxacin was 7.0±1.2 µg/g in lung tissues and 9.4±2.1 µg/g in bronchial mucosa. The corresponding area under the curve between 0 and 24 h (AUC0-24) was 85.7±8.5 and 137.3±19.4 µg h/g. The mean permeability of levofloxacin (ratio of concentration in tissue to that in plasma) was 2.4 in lung tissue and 4.4 in the bronchial mucosa. The PK profiles of levofloxacin in the plasma, lung and bronchial mucosa were described using an integrated one-compartment model. The probability of fAUC0-24/minimal inhibitory concentration (MIC) target attainment of levofloxacin against Streptococcus pneumoniae in the lung and bronchial mucosa was maintained at 100% when MIC ≤1 mg/l, while the cumulative fraction of fAUC0-24/MIC in the corresponding tissues was 94.4 and 98.1%, respectively. The present study demonstrated the high permeability of levofloxacin in the lung and bronchial mucosa of patients undergoing pulmonary surgery. In conclusion, treatment using 500 mg levofloxacin exhibits good clinical and microbiological efficacy for use in LRTIs that are caused by S. pneumoniae. This trial was registered retrospectively in the Chinese Clinical Trial Registry on January 13, 2020 (registration no. ChiCTR2000029096).

Diagnostic Utility of Serology and Polymerase Chain Reaction for Detection of Mycoplasma pneumoniae and Chlamydophila pneumoniae in Paediatric Community-acquired Lower Respiratory Tract Infections

AbstractPurpose:Mycoplasma pneumoniae (M. pneumoniae) and Chlamydophila pneumoniae (C. pneumoniae) play a significant role in children of all ages with lower respiratory tract infections (LRTIs). This study was conducted to detect M. pneumoniae and C. pneumoniae in children with community-acquired LRTIs employing serology, polymerase chain reaction (PCR) and nested PCR analysis. Material and Methods: This study included 75 children with acute LRTIs for detection of M. pneumoniae and C. pneumoniae. Blood was obtained for M. pneumoniae and C. pneumoniae antibodies and nasopharyngeal aspirates for M. pneumoniae PCR and C. pneumoniae nested PCR. Results:M. pneumoniae infection was positive in 9 (64.21%) children aged 2–6 months and in 5 (35.79%) aged 7 months–12 years, and this difference was statistically significant (P = 0.002). C. pneumoniae infection was comparable within the age group and statistically insignificant (P = 0.43). Clinical and radiological profiles of M. pneumoniae- and C. pneumoniae-positive and negative patients were numerically comparable. Serology and PCR together detected M. pneumoniae infection in 14 (18.6%) children. The sensitivity, specificity and positive and negative predictive values of serology were 77.78%, 92.42%, 58.33% and 96.83%, respectively. C. pneumoniae infection was positive in 11 (14.6%) children by serology and nested PCR with 50% sensitivity, 87.67% specificity, 10% positive predictive value and 98.46% negative predictive value. Conclusions: Our study confirms that M. pneumoniae and C. pneumoniae play a significant role in community-acquired LRTIs and a combination of serology and nested PCR is useful for its diagnosis.

Immunoglobulin M profile of viral and atypical pathogens among children with community acquired lower respiratory tract infections in Luzhou, China

BackgroundCommunity-acquired lower respiratory tract infections (CA-LRTIs) are the primary cause of hospitalization among children globally. A better understanding of the role of atypical pathogen infections in native conditions is essential to improve clinical management and preventive measures. The main objective of this study was to detect the presence of 7 respiratory viruses and 2 atypical pathogens among hospitalized infants and children with community-acquired lower respiratory tract infections in Luzhou via an IgM test.MethodsOverall, 6623 cases of local hospitalized children with 9 pathogen-IgM results from 1st July 2013 to 31st Dec 2016 were included; multidimensional analysis was performed.Results1) Out of 19,467 hospitalized children with lower respiratory tract infections, 6623 samples were collected, for a submission ratio of 33.96% (6623 /19467). Of the total 6623 serum samples tested, 5784 IgM stains were positive, for a ratio of 87.33% (5784 /6623). Mycoplasma pneumoniae (MP) was the dominant pathogen (2548 /6623, 38.47%), with influenza B (INFB) (1606 /6623, 24.25%), Legionella pneumophila serogroup 1 (LP1) (485 /6623, 7.32%) and parainfluenza 1, 2 and 3(PIVs) (416 /6623, 6.28%) ranking second, third and fourth, respectively.2) The distribution of various pathogen-IgM by age group was significantly different (χ2 = 455.039, P < 0.05).3) Some pathogens were found to be associated with a certain age of children and seasons statistically.ConclusionsThe dominant positive IgM in the area was MP, followed by INFB, either of which prefers to infect children between 2 years and 5 years in autumn. The presence of atypical pathogens should not be underestimated clinically as they were common infections in the respiratory tract of children in the hospital.

β2 microglobulin and lactate dehydrogenase are indices of different features of Mycoplasma pneumoniae-associated community-acquired lower respiratory tract infection for severity evaluation in children

Using the hospital records, we retrospectively assessed whether urinary β2 microglobulin/creatinine ratio (UBCR) and lactate dehydrogenase (LD) values could be used to estimate the severity of Mycoplasma pneumoniae-associated lower respiratory tract infection (MP-LRTI). We studied 48 patients with MP-LRTI (median age, 7.5 years; range, 3–14 years) admitted to Kagoshima City Hospital and examined the relationships of the UBCR or LD values with fever and pulmonary tissue damage (hypoxemia and severity assessments on chest radiographs). Patients were assigned to four groups based on whether they had fever and/or hypoxemia. Patients with high fever showed significantly higher UBCR values than those without (P < 0.05), whereas those with hypoxemia showed higher LD values than those without (P = 0.001). The maximum body temperature on admission was closely associated with the UBCR but not with LD levels. In chest radiography assessments, LD levels were significantly higher in patients with severe than mild or moderate MP-LRTI. A cut-off LD level of 530 IU/L showed a very high sensitivity (100%) and specificity (93%). Although UBCR values were higher in patients with severe MP-LRTI, the differences were not statistically significant. Our study shows that the UBCR is associated with body temperature, whereas LD levels may serve as an index of pulmonary tissue damage in children with MP-LRTI.

Serological and molecular detection of Mycoplasma pneumoniae in children with community-acquired lower respiratory tract infections

This study was designed to evaluate the incidence of Mycoplasma pneumoniae infection in children with community-acquired lower respiratory tract infections (LRTIs). A total of 245 patients 6 months to 12 years of age were investigated for M. pneumoniae employing serological tests, polymerase chain reaction (PCR), nested PCR, and reverse transcription PCR (RT-PCR) on throat swab samples. Forty five (59.2%) children <5 years and 31 (40.7%) children ≥5 years age group were positive for M. pneumoniae infection, and this difference was statistically significant (P ≤ 0.01).Clinical and radiological findings across M.pneumoniae–positive and –negative cases were comparable. Serology, PCR, nested PCR, and RT-PCR together detected M. pneumoniae infection in 76 (31%) patients. Sensitivity, specificity, and positive and negative predictive values of PCR were 16.18%, 95.48%, 57.89%, and 74.78%, respectively, and those of serology were 57.89%, 74.78%, 16.18%, and 95.48%, respectively. Serological and molecular detection in combination is useful for rapid and reliable diagnosis of M. pneumoniae infections in children with LRTIs.