Etiological diagnosis of suppurative bacterial meningitis today

As the result of laboratory examination of 2165 patients with virulent bacterial meningitides, including cases of meningococcal infection, the etiological diagnosis was confirmed in 1407 patients (65.0%), the number of cases confirmed by the laboratory examination being significantly greater among adults than among children: 67.5 +/- 1.37% and 63.1 +/- 1.53%, respectively, (t = 2.1). Meningococcal infection was confirmed in 1111 (70.6%) out of 1572 patients under examination. Of the patients with purulent meningitides, pneumococcal etiology was determined in 27.4%, type b of Haemophilus influenzae in 13.5%, other infective agents in 10.0%. The comparison of the results obtained in the examination, carried out by different methods, of 946 children and 770 adults with meningococcal infection revealed a considerable difference in the number of positive results yielded by the bacteriological method and countercurrent immunoelectrophoresis (CIE). Among adults meningococci were isolated twice as frequently (41.1 +/- 2.5% - 19.4 +/- 1.6%), and the results yielded by CIE were predominantly positive (55.1 +/- 2.5% and 40.1 +/- 2.5%). CIE and the immunoenzyme assay were shown to have advantages in the diagnosis of the disease. Under the conditions of intensive antibiotic therapy the methods based on the detection of specific antigens in body fluids can greatly assist in diagnosis.     

Early detection and rapid identification of Streptococcus pneumoniae and Haemophilus influenzae in acute pneumonias

The comparative study of the diagnostic value of the enzyme immunoassay (EIA), indirect immunofluorescence (IF) and countercurrent immunoelectrophoresis (CIE) was made. The serological identification of the isolated and reference pneumococci (19) and H. influenzae (38) strains revealed the possibility of using all three microanalytical methods for this purpose. The study of pneumococcal and H. influenzae antigens in native sputum obtained from 74 patients with acute pneumonia showed that EIA and indirect IF were highly sensitive, their sensitivity considerably exceeding that of the bacteriological analysis. Pneumococcal antigens were detected in 66.2% of patients by EIA and in 54.0% of patients by indirect IF, while H. influenzae antigens were detected in 58.1% of patients by EIA and in 67.6% of patients by indirect IF. The sensitivity of CIE proved to be considerably lower; in the detection of pneumococcal antigens it was level with the sensitivity of the bacteriological analysis (23.0%) and H. influenzae antigens could be detected only in 27.0% of patients.     

Genome Sequence of Multidrug-Resistant Escherichia coli EC302/04, Isolated from a Human Tracheal Aspirate

Escherichia coli is an important etiologic agent of lower respiratory tract infections (LRTI). Multidrug-resistant E. coli EC302/04 was isolated from a tracheal aspirate, and its genome sequence is expected to provide insights into antimicrobial resistance as well as adaptive and virulence mechanisms of E. coli involved in LRTI.     

Accelerated laboratory diagnosis of bacterial pneumonia

The effectiveness of countercurrent immunoelectrophoresis (CIE) used for the accelerated differential diagnosis of pneumococcal, staphylococcal, mycoplasmal and Legionella infections in cases of pneumonia has been shown. The presence of correlation between the results obtained in the bacterial study of sputa and bronchial washings and in CIE has been revealed, which gives grounds for recommending CIE for the accelerated diagnosis of pneumococcal pneumonia on the basis of the analysis of sputa, bronchial washings and blood sera obtained from patients. In Legionella infection the passive hemagglutination test with antigenic diagnostica has proved to be more effective for accelerated diagnosis than CIE.     

The Diagnosis of Pneumococcal Chest Infection by Counter-Current-Immunoelectrophoresis

A simple, inexpensive method of counter-current-immunoelectrophoresis was used to detect pneumococcal antigens in sputum, serum and pleural fluid. Antigens were detected in sputa from 69% of subjects with pneumococcal pneumonia and there was a good correlation with the certainty of the clinical diagnosis. Serum antigens were found in 12.5% of subjects with either a definite or a presumed diagnosis and in one case from a patient who was not thought to have pneumococcal pneumonia. The pathogenic importance of antigens in the sputa of patients with a history of chronic respiratory disease was uncertain. Counter-current-immunoelectrophoresis was more sensitive than routine bacteriological methods for demonstrating the presence of pneumococci in pleural fluids.     

Evaluation of the Uro4 HB&L™ system for the rapid diagnosis of lower respiratory tract infections in intensive care units

Respiratory tract infection is a common and important problem in the intensive care unit (ICU) setting. It has been demonstrated that an appropriate initial regimen or its early modification (within 6-12 h from diagnosis) based on microbiological results leads to a higher survival rate. Here we evaluated the Uro4 HB&L™ automated system for the rapid diagnosis of respiratory tract infections in ICU patients. A total of 644 lower respiratory tract specimens collected from 400 inpatients from nine ICUs at the Padova University hospital were collected during a 12-month period. All samples were processed both with the Uro4 HB&L™ system and with the reference culture method. Out of 322 samples, 312 were concordant positive, 276 out of 276 were concordant negative, 66 samples were declared uncertain and discarded because of an excess in turbidity. The diagnostic accuracy was good, compared with standard cultures from BAL specimens, in terms of sensitivity (0.972), specificity (1.00), likelihood ratios and diagnostic odds ratio. Ten discordant samples, resulted positive with the reference culture and not detectable with the Uro4 HB&L™, were confirmed positive by Gram-stain smear analysis performed after incubation. The Uro4 HB&L™ system, compared to the standard culture method, revealed a very high sensitivity and a full specificity in identifying clinically relevant microorganisms from lower respiratory tract samples after merely 6 h. Overall our results indicate that Uro4 HB&L™ is a reliable system for the surveillance of the respiratory tract infections in ICUs; it could speed up the laboratory procedures and provide fast, reliable results for clinicians.     

Long-Term Shedding of Influenza Virus,Parainfluenza Virus,Respiratory Syncytial Virus and Nosocomial Epidemiology in Patients with Hematological Disorders

Respiratory viruses are a cause of upper respiratory tract infections (URTI), but can be associated with severe lower respiratory tract infections (LRTI) in immunocompromised patients. The objective of this study was to investigate the genetic variability of influenza virus, parainfluenza virus and respiratory syncytial virus (RSV) and the duration of viral shedding in hematological patients. Nasopharyngeal swabs from hematological patients were screened for influenza, parainfluenza and RSV on admission as well as on development of respiratory symptoms. Consecutive swabs were collected until viral clearance. Out of 672 tested patients, a total of 111 patients (17%) were infected with one of the investigated viral agents: 40 with influenza, 13 with parainfluenza and 64 with RSV; six patients had influenza/RSV or parainfluenza/RSV co-infections. The majority of infected patients (n = 75/111) underwent stem cell transplantation (42 autologous, 48 allogeneic, 15 autologous and allogeneic). LRTI was observed in 48 patients, of whom 15 patients developed severe LRTI, and 13 patients with respiratory tract infection died. Phylogenetic analysis revealed a variety of influenza A(H1N1)pdm09, A(H3N2), influenza B, parainfluenza 3 and RSV A, B viruses. RSV A was detected in 54 patients, RSV B in ten patients. The newly emerging RSV A genotype ON1 predominated in the study cohort and was found in 48 (75%) of 64 RSV-infected patients. Furthermore, two distinct clusters were detected for RSV A genotype ON1, identical RSV G gene sequences in these patients are consistent with nosocomial transmission. Long-term viral shedding for more than 30 days was significantly associated with prior allogeneic transplantation (p = 0.01) and was most pronounced in patients with RSV infection (n = 16) with a median duration of viral shedding for 80 days (range 35–334 days). Long-term shedding of respiratory viruses might be a catalyzer of nosocomial transmission and must be considered for efficient infection control in immunocompromised patients.     

Etiology of acute pneumonia occurring against a background of influenza and other acute respiratory viral infections

The etiology of acute pneumonia (AP) was studied in 229 patients who had the disease simultaneously with influenza (106 patients), other viral and mycoplasmal infections (48 patients), and without concomitant acute viral infections (75 patients). The use of the quantitative microbiological method and the indirect immunofluorescence test with autostrains or Streptococcus pneumoniae strains of serotypes 2, 3, and 6, prevailing in Leningrad in patients with acute inflammatory diseases of the lungs, made it possible to find out the pneumococcal etiology of AP in 95% of patients irrespective of the presence of acute respiratory viral infections. The etiological role of opportunistic bacteria was revealed in 13 AP patients (5.7%); in 2 of them the causative agent of AP was Staphylococcus aureus and in 11, various species of Gram-negative enterobacteria. The latter were the cause of complications in 8 cases of pneumococcal pneumonia.     

ELISA间接法检测呼吸道合胞病毒和副流感病毒血清IgM和IgA抗体

建立了检测呼吸道合胞病毒(RSV)和副流感病毒(PFV)血清特异性IgM和IgA抗体的间接ELISA方法。在方法统一的基础上比较了检测IgG、IgM和IgA抗体的结果,证明检测血清IgM和IgA可以作为RSV和PFV感染的早期诊断指标。检测了120份临床急性下呼吸道感染患儿的血清,RSV-IgM检出率为33.3％,RSV-IgA为36.7％;PFV-IgM为27.5％,PFV-IgA为31.6％。提出了对RSV和PFV感染以检测特异性IgA替代IgM或两者互补的设想。     

High viral load of human bocavirus correlates with duration of wheezing in children with severe lower respiratory tract infection

Background

Human bocavirus (HBoV) is a newly discovered parvovirus and increasing evidences are available to support its role as an etiologic agent in lower respiratory tract infection (LRTI). The objective of this study is to assess the impact of HBoV viral load on clinical characteristics in children who were HBoV positive and suffered severe LRTI.

Methods

Lower respiratory tract aspirates from 186 hospitalized children with severe LRTI were obtained by bronchoscopy. HBoVs were detected by real-time PCR and other 10 infectious agents were examined using PCR and/or direct fluorescent assay.

Results

Thirty-one patients (24.6%) were tested positive for HBoV in the respiratory tract aspirates. Fifteen samples had a high viral load (>10⁴ copies/mL) and the other sixteen samples had a low viral load (<10⁴ copies/mL). The duration of presented wheezing and hospitalization was longer in children with high viral load of HBoV than that in children with low viral load. The days of wheezing showed a correlation with viral load of HBoV.

Conclusion

We confirmed that HBoV was frequently detected in patients with severe LRTI. Wheezing was one of the most common symptoms presented by patients with positive HBoV. A high HBoV viral load could be an etiologic agent for LRTI, which led to more severe lower respiratory tract symptom, longer duration of wheezing and hospitalization.     

280例呼吸道感染儿童呼吸道病毒病原学检出情况及流行规律分析

目的:了解呼吸道感染儿童呼吸道病毒病原学检出情况及其流行规律,为儿童呼吸道感染的预防、诊断及治疗提供病原学依据。方法:选取2016年1月-2017年12月期间中国人民解放军中部战区总医院收治的280例呼吸道感染患儿为研究对象,分析患儿呼吸道分泌物中呼吸道病毒的检出情况,并分析呼吸道感染儿童呼吸道病毒感染与年龄、季节、疾病类型的关系。结果:280例呼吸道感染患儿中共检出98份阳性标本,阳性率为35.00%,其中有2份标本中检出2种病毒感染,混合感染阳性率为0.71%;在所有病毒类型中,呼吸道合胞病毒(RSV)病毒感染阳性率最高。1岁患儿的病毒感染阳性率最高,与其他年龄段病毒感染阳性率比较差异有统计学意义(P0.05)。呼吸道感染患儿春季、冬季的病毒感染阳性率明显高于夏季、秋季(P0.05)。不同呼吸道感染疾病类型患儿病毒感染阳性率比较差异有统计学意义(P0.05),以喘息性肺炎、毛细支气管炎、肺炎患儿病毒感染阳性率较高。结论:RSV是呼吸道感染儿童呼吸道病毒感染的主要致病病原体,1岁的婴幼儿较易感染,春季、冬季为其高发季节,且以肺炎、毛细支气管炎、喘息性肺炎患儿的病毒感染阳性率较高。     

Lower Respiratory Tract Infections Associated with Rhinovirus during Infancy and Increased Risk of Wheezing during Childhood. A Cohort Study

Background and Objectives

Although association between respiratory syncytial virus infection and later asthma development has been established, little is known about the role of other respiratory viruses. Rhinovirus was considered a mild pathogen of the upper respiratory tract but current evidence suggests that rhinovirus is highly prevalent among children with lower respiratory tract infections (LRTI). The aim of the study was to evaluate whether LRTI hospitalization associated with rhinovirus during infancy was associated with an increased risk of wheezing – a proxy measure of asthma – during childhood.

Methods

During a 12 months period, all infants <1 year admitted to Manhiça District Hospital with symptoms of LRTI who survived the LRTI episode, were enrolled in the study cohort. Nasopharyngeal aspirates were collected on admission for viral determination and study infants were classified according to presence or not of rhinovirus. The study cohort was passively followed-up at the Manhiça District Hospital for up to 4 years and 9 months to evaluate the association between LRTI associated with rhinovirus in infancy and wheezing during childhood.

Findings and Conclusions

A total of 220 infants entered the cohort; 25% of them had rhinovirus detected during the LRTI episode as opposed to 75% who tested negative for rhinovirus. After adjusting for sex and age and HIV infection at recruitment, infants hospitalized with LRTI associated with rhinovirus had higher incidence of subsequent visits with wheezing within the year following hospitalization [Rate ratio=1.68, (95% confidence interval=1.02-2.75); Wald test p-value = 0.039]. No evidence of increased incidence rate of visits with wheezing was observed for the remaining follow-up period. Our data suggest a short term increased risk of wheezing after an initial episode of LRTI with RV.     

Pathogen-specific circulating plasmablasts in patients with pneumonia

Lower respiratory tract infections (LRTI) are the leading cause of death world-wide, with Streptococcus pneumoniae (Pnc) as the most prevalent pathogen. Local immune mechanisms appear central to protection against the disease, yet they are poorly characterized. Infections at other, non-respiratory mucosal sites are associated with a transient circulation of mucosa-originating lymphocytes from the mucosal site to blood and back to the mucosa. The present study explored whether pathogen-specific plasmablasts appear in the circulation also in patients with infection of the lower respiratory tract. 16 patients with bacteremic Pnc pneumonia and 14 healthy volunteers were explored for circulating plasmablasts secreting antibodies against their own pathogenic Pnc strain isolated in blood cultures (patients) or against several pathogenic strains from pneumonia patients (14 controls) or a mixture of nine different purified pneumococcal polysaccharides (8 controls). Both patients and volunteers were studied for all plasmablasts. The cells were identified with ELISPOT as Pnc-specific antibody-secreting cells (ASC) and as all immunoglobulin-secreting cells (ISC). High numbers of circulating Pnc-specific ASC were found in the acute phase of the disease in all patients with pneumonia (median 97 ASC/10(6) PBMC), but in none of the controls. IgG isotype predominated in 9/16 patients. The numbers of ISC were significantly higher in the patients than in the healthy controls, yet Pnc-specific ASC only accounted for 0.7% of all the patients' ISC.The present study is the first to show that antigen-specific plasmablasts appear in the circulation in pneumonia, suggesting that pulmonary lypmhocytes recirculate in humans. Assessing these cells provides a novel tool for studying immune response to antigens encountered at the LRT.     

呼吸重症监护病房2008年至2011年医院感染病原菌分布及危险因素分析

目的：对我院呼吸重症监护病房（RICU）临床分离的非重复性感染病原菌的耐药性进行调查,分析RICU院内感染的危险因素。方法：收集RICU 2008年-2011年临床分离的非重复性感染病原菌及相关临床资料分析医院感染的危险因素。结果：（1）2008-2011年RICU院内感染发生率为34.15%,每年分离的前3位病原菌均为鲍曼不动杆菌、金黄色葡萄球菌及铜绿假单胞菌;（2）大肠杆菌连续4年ESBLs检出率为100%,四年间肺炎克雷伯菌ESBLs检出率最高达95.5%,葡萄球菌中MRSA检出率较高（〉89.6%）;（3）RICU院内感染以下呼吸道感染最为常见,其次为泌尿道感染,血液感染位于第3位;（4）多因素非条件logistic回归分析发现机械通气、住院时间〉15天及联合应用抗菌药物是RICU医院感染的危险因素。结论：（1）连续4年RICU感染病原菌以革兰阴性杆菌为主;（2）ESBLs和MRSA检出率较高,给临床抗感染治疗带来巨大的挑战;（3）机械通气、住院时间〉15天及联合应用抗菌药物是RICU医院感染的危险因素。     

Two cases of severe invasive infections in children caused by <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> serotype 14 — <Emphasis Type="Italic">case report</Emphasis>

Two cases are presented of severe pneumococcal infections in infants caused by serotype 14 Streptococcus pneumoniae. The first case — meningitis — caused by S. pneumoniae (pneumococcus) with lowlevel penicillin susceptibility has developed from acute otitis media and resulted in fatal outcome. The second one — an immunocompromised child presenting recurrent otitis and chronic mastoiditis developed into pneumococcal pneumonia. Both cases demonstrate the extreme importance of a relevant initial treatment of localized pneumococcal infections, preventing the development of generalized infection. Amoxicillin (an oral treatment option in both upper and lower respiratory tract infections caused also by Pneumococcus strains with low-level penicillin susceptibility due to its beneficial pharmacokinetics and pharmacodynamics) was not used in either case.     

Aetiology of Acute Respiratory Tract Infections in Hospitalised Children in Cyprus

In order to improve clinical management and prevention of viral infections in hospitalised children improved etiological insight is needed. The aim of the present study was to assess the spectrum of respiratory viral pathogens in children admitted to hospital with acute respiratory tract infections in Cyprus. For this purpose nasopharyngeal swab samples from 424 children less than 12 years of age with acute respiratory tract infections were collected over three epidemic seasons and were analysed for the presence of the most common 15 respiratory viruses. A viral pathogen was identified in 86% of the samples, with multiple infections being observed in almost 20% of the samples. The most frequently detected viruses were RSV (30.4%) and Rhinovirus (27.4%). RSV exhibited a clear seasonality with marked peaks in January/February, while rhinovirus infections did not exhibit a pronounced seasonality being detected almost throughout the year. While RSV and PIV3 incidence decreased significantly with age, the opposite was observed for influenza A and B as well as adenovirus infections. The data presented expand our understanding of the epidemiology of viral respiratory tract infections in Cypriot children and will be helpful to the clinicians and researchers interested in the treatment and control of viral respiratory tract infections.     

Rational antimicrobial pharmacotherapy of secondary infections in patients with pulmonary tuberculosis]

The results of 3-year (2002-2004) local microbiological monitoring of secondary infections due to opportunistic microflora that complicated the treatment of the main disease in patients of a regional (Moscow) tuberculosis hospital are presented. The monitoring revealed the leading microorganisms, the etiological agents of the secondary lower respiratory tract infection in the patients with pulmonary tuberculosis. The level of their resistance to the up-to-date antimicrobials was determined. Recommendations for optimization of antibacterial therapy of patients with pulmonary tuberculosis complicated by secondary lower respiratory tract infection due to opportunistic microorganisms were developed and validated.     

Streptococcus pneumoniae Enhances Human Respiratory Syncytial Virus Infection In Vitro and In Vivo

Human respiratory syncytial virus (HRSV) and Streptococcus pneumoniae are important causative agents of respiratory tract infections. Both pathogens are associated with seasonal disease outbreaks in the pediatric population, and can often be detected simultaneously in infants hospitalized with bronchiolitis or pneumonia. It has been described that respiratory virus infections may predispose for bacterial superinfections, resulting in severe disease. However, studies on the influence of bacterial colonization of the upper respiratory tract on the pathogenesis of subsequent respiratory virus infections are scarce. Here, we have investigated whether pneumococcal colonization enhances subsequent HRSV infection. We used a newly generated recombinant subgroup B HRSV strain that expresses enhanced green fluorescent protein and pneumococcal isolates obtained from healthy children in disease-relevant in vitro and in vivo model systems. Three pneumococcal strains specifically enhanced in vitro HRSV infection of primary well-differentiated normal human bronchial epithelial cells grown at air-liquid interface, whereas two other strains did not. Since previous studies reported that bacterial neuraminidase enhanced HRSV infection in vitro, we measured pneumococcal neuraminidase activity in these cultures but found no correlation with the observed infection enhancement in our model. Subsequently, a selection of pneumococcal strains was used to induce nasal colonization of cotton rats, the best available small animal model for HRSV. Intranasal HRSV infection three days later resulted in strain-specific enhancement of HRSV replication in vivo. One S. pneumoniae strain enhanced HRSV both in vitro and in vivo, and was also associated with enhanced syncytium formation in vivo. However, neither pneumococci nor HRSV were found to spread from the upper to the lower respiratory tract, and neither pathogen was transmitted to naive cage mates by direct contact. These results demonstrate that pneumococcal colonization can enhance subsequent HRSV infection, and provide tools for additional mechanistic and intervention studies.     

Etiological structure of pneumonias in children and adults

The bacteriological study of sputa, nasopharyngeal smears and bronchial washings taken from pneumonia patients has shown that the leading etiological agent was Streptococcus pneumoniae isolated in the diagnostic titre (10(7) bacteria per ml) in 78.1% of the cases. Staphylococcus aureus, Haemophilus influenzae, enterobacteria and yeast-like fungi have been found to play an insignificant role in the etiology of acute pneumonia (2.5 +/- +/- 0.9%). The results of the serological diagnosis by means of the complement fixation test have revealed that, alongside S. pneumoniae, the following infective agents are of etiological importance in cases of acute pneumonia: respiratory viruses (more than 50%), Mycoplasma pneumonia (10%), Chlamydia psittaci (6.4%) and Legionella pneumophila (3.8%). The study has first revealed that, under the conditions of Alma-Ata, serotypes 19, 23, 8 and 4 prevail among circulating pneumococci. This study has also shown that the use of M. pneumoniae antibody erythrocyte diagnosticum enhances the detection rate of mycoplasma infections in pneumonia patients.