Nasopharyngeal Swab Culture Research Articles

Long-term outcomes and risk factors for early bacterial infection after pediatric liver transplantation: a prospective cohort study.

Liver transplantation (LT) is the most efficient treatment for pediatric patients with end-stage liver diseases, while bacterial infection is the leading reason for post-transplant mortality. The present study is to explore the outcomes and risk factors of early bacterial infection (within 1 months) after pediatric LT. In this prospective cohort study, 1316 pediatric recipients [median (IQR) age: 9.1 (6.3-28.0) months; male: 48.0%; median (IQR) follow-up time: 40.6 (29.1-51.4) months] who received LT from September 2018 to April 2022 were included. Bacterial culture samples such as sputum, abdominal drainage, blood, and so on were collected when recipients were presented with infective symptoms. Kaplan-Meier analysis was applied to estimate the long-term survival rates and logistic regression was used to identify independent risk factors. To explore the role of pretransplant rectal swab culture (RSC) in reducing post-transplant bacterial infection rate, 188 infant LT recipients [median (IQR) age: 6.8 (5.5-8.1) months; male: 50.5%] from May 2022 to September 2023 were included. Log-binomial regression was used to measure the association of pretransplant RSC screening and post-transplant bacterial infection. The 'Expectation Maximization' algorithm was used to impute the missing data. Bacterial infection was the primary cause for early (38.9%) and overall mortality (35.6%) after pediatric LT. Kaplan-Meier analysis revealed inferior 1-year and 5-year survival rates for recipients with post-transplant bacterial infection (92.6 vs. 97.1%, 91.8 vs. 96.4%, respectively; P <0.001). Among all detected bacteria, Staphylococcus spp. (34.3%) and methicillin-resistant coagulase-negative Staphylococci (43.2%) were the dominant species and multidrug resistant organisms, respectively. Multivariable analysis revealed that infant recipients [adjusted odds ratio (aOR) 1.49; 95% CI: 1.01-2.20], male recipients (aOR, 1.43; 95% CI: 1.08-1.89), high graft-to-recipient weight ratio (aOR, 1.64; 95% CI: 1.17-2.30), positive post-transplant RSC (aOR, 1.45; 95% CI: 1.04-2.02) and nasopharyngeal swab culture (aOR 2.46; 95% CI: 1.72-3.52) were independent risk factors for early bacterial infection. Furthermore, RSC screening and antibiotic prophylaxis before transplantation could result in a relatively lower post-transplant infection rate, albeit without statistical significance (adjusted RR, 0.53; 95% CI: 0.25-1.16). In this cohort study, post-transplant bacterial infection resulted in an inferior long-term patient survival rate. The five identified independent risk factors for post-transplant bacterial infection could guide the prophylaxis strategy of post-transplant bacterial infection in the future. Additionally, pretransplant RSC might decrease post-transplant bacterial infection rate.

Evaluation of antibody responses in healthcare workers before & after meningococcal vaccine and determination of meningococcal carriage rates

The rates of nasopharyngeal meningococcal carriage in healthcare workers are unknown. Meningococcal vaccine is recommended for risk groups but healthcare workers are not included in risk groups for many countries. Herein, we aimed to investigate the nasopharyngeal meningococcal carriage rates, basal and after one dose of Men-ACWY-DT vaccine response on the 30th day by evaluating meningococcus IgG antibody levels and decolonization at month six after vaccination among the detected carriers. Nasopharyngeal swab samples were taken before vaccination to evaluate meningococcal carriage in healthcare workers. All participants received a single dose of Men-ACWY-DT vaccine. Serum samples were collected immediately before vaccination and again on day 30 post-vaccination. Antibodies in the stored sera were analyzed using the ELISA method. Participants who were determined to carry meningococci at the initial visit underwent another round of nasopharyngeal swab tests six months post-vaccination to check for decolonization. Between November 2020 and May 2021, we evaluated samples from 100 physicians [52 % females, 28.28 ± 4.45 (min: 24, max: 49)]. The majority of the physicians worked in the emergency department (45 %), followed by the infectious diseases clinic (14 %). Fifty-eight physicians had a history of at least one contact with a meningococcus-infected patient, and 53 (91.4 %) had used prophylactic antibiotics at least once due to this exposure. None of the study group nasopharyngeal swab cultures were positive for Neisseria meningitidis. Before the Men-ACWY-DT vaccine, anti-meningococcus IgG positivity was detected in the serum samples of only 3 (3 %) participants. By day 30 after vaccination, 48 % of participants showed positive for antibodies. As we didn’t detect nasopharyngeal carriage in any participants, we didn’t evaluate decolonization among carriers six months post-vaccination. Notably, detection of antibodies was evident in about half of the participants on day 30 after receiving a single dose of the Men-ACWY-DT vaccine.

Etiology of bacterial community-acquired pneumonia among hospitalized children in Hai Phong Children’s Hospital

The objectives of this study were to determine the etiology of bacterial community-acquired pneumonia (CAP) in children hospitalized at Hai Phong Children’s Hospital (HCH) in 2019 and these bacteria’s antibiotic resistance properties. The subjects were the qualified medical records of all inpatients at the Respiratory Department of Hai Phong Children’s Hospital aging from 1 month to 15 years old diagnosed with CAP according to the diagnostic criteria of the World Health Organization with positive nasopharyngeal swab culture results from January 1st, 2019, to December 31st, 2019. The sample size included all medical records of patients who met the inclusion criteria of this research during the study period. The success rate of nasopharyngeal swab culture test of CAP patients was 638/1605 (39.7%). The most common pathogens of CAP in children at HCH were S. aureus, S. pneumoniae, H. influenzae and M. catarrhalis. Antibiogram revealed that each of them showed high resistance to a various type of antibiotics. Our study also provided valuable data on the antibiotic sensitivity and raised alarm over presence of multidrug-resistant bacteria inducing CAP in children.

Diagnostic Accuracy of Nasopharyngeal Swab Cultures in Children Less Than Five Years with Chronic Wet Cough.

Background: It is necessary to find a non-invasive and accurate procedure to predict persistent bacterial bronchitis (PBB) causative organisms and guide antibiotic therapy. The study objective was to compare the diagnostic accuracy of nasopharyngeal swab cultures with bronchoalveolar lavage (BAL) cultures in children with PBB. Methods: Nasopharyngeal swab and BAL fluid specimens were collected and cultured for bacterial pathogens prospectively from less than five-year-old children undergoing flexible bronchoscopy for chronic wet cough. Results: Of the 59 children included in the study, 26 (44.1%) patients had a positive BAL bacterial culture with neutrophilic inflammation. Prevalence of positive cultures for any of the four common respiratory pathogens implicated in PBB (Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae) was significantly higher (p = 0.001) in NP swabs compared to BAL fluids (86.4% and 44.1% of PBB cases, respectively). NP swab cultures for any of the four main bacterial pathogens had 85% (95% CI: 65–96%) and 48% (95% CI: 31–66%) sensitivity and specificity of detecting PBB, respectively. Positive and negative predictive values were 56% (95% CI: 47–65%) and 80% (95% CI: 60–91%), respectively. In conclusion, in children less than 5 years of age with chronic wet cough (PBB-clinical), a negative NP swab result reduces the likelihood of lower airway infection; however, a positive NP swab does not accurately predict the presence of lower airway pathogens. Flexible bronchoscopy should be considered in those with recurrent PBB-clinical or with clinical pointers of central airway anomalies.

Clinico- bacteriological profile of Community Acquired Pneumonia (CAP) in children aged 3-59 months: A cross sectional study

Background: Worldwide community-acquired pneumonia (CAP) is the major cause of high mortality among under five children in India. After introduction of Pneumococcal and H. influenzae vaccination there is paucity of data regarding etiological profile of pneumonia.&#x0D; Aims and Objective: To evaluate the Clinico- epidemiological profile and etiology of community acquired pneumonia in children.&#x0D; Materials and Methods: We enrolled children aged 3-59 months with CAP (based on WHO criteria of tachypnea with cough or breathing difficulty) over 18 months and recorded presenting symptoms, clinical signs and chest radiography. We performed blood and nasopharyngeal swab (NPS) bacterial culture simultaneously to detect etiological agent of community acquired pneumonia in children.&#x0D; Results: Out of 150 cases of CAP, 90 % of caeses had cough and fever and nearly 80-90% cases had tachypnea and crackles on examination. Radiological findings suggestive of pneumonia was seen in 86% cases . Most common organism isolated was S aureus in both NPS culture (18.7 %) and blood culture (14.7 %). Other common organisms detected in NPS culture were S pneumoniae (6%), E Coli (4.7%), Klebsiella (4.7%), CONS (3.3%), and Pseudomonas (2.7%). In blood culture the common organism detected after S aureus was E coli (5.3%), S pneumoniae (3.3%), Klebsiella (3.3%), CONS( 3.8%), and Pseudomonas (2.5%).&#x0D; Conclusions: We observed that S aureus was the predominant etiological organism isolated in both blood and nasopharyngeal swab bacterial culture in patients suffering from community-acquired pneumonia.

Nasopharyngeal Carriage of Methicillin-Resistant Staphylococcus aureus (MRSA) among Sickle Cell Disease (SCD) Children in the Pneumococcal Conjugate Vaccine Era.

The aim of this cross-sectional study was to investigate Staphylococcus aureus nasopharyngeal carriage epidemiology in relation to other nasopharyngeal bacterial colonizers among sickle cell disease (SCD) children about five years into pneumococcal conjugate vaccine 13 (PCV-13) introduction in Ghana. The study involved bacteriological culture of nasopharyngeal swabs obtained from 202 SCD children recruited from the Princess Marie Louise Children’s Hospital. S. aureus isolates were identified using standard methods and subjected to antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method. Cefoxitin-resistant S. aureus isolates were screened for carriage of the mecA, pvl, and tsst-1 genes using multiplex polymerase chain reaction. The carriage prevalence of S. aureus was 57.9% (n = 117), and that of methicillin-resistant S. aureus (MRSA) was 3.5% (n = 7). Carriage of the mecA, pvl, and tsst-1 genes were respectively demonstrated in 20.0% (n = 7), 85.7% (n = 30), and 11.4% (n = 4) of the cefoxitin-resistant S. aureus isolates. PCV-13 vaccination (OR = 0.356, p = 0.004) and colonization with coagulase-negative staphylococci (CoNS) (OR = 0.044, p < 0.0001) each protected against S. aureus carriage. However, none of these and other features of the participants emerged as a determinant of MRSA carriage. The following antimicrobial resistance rates were observed in MRSA compared to methicillin-sensitive S. aureus: clindamycin (28.6% vs. 4.3%), erythromycin (42.9% vs. 19.1%), tetracycline (100% vs. 42.6%), teicoplanin (14.3% vs. 2.6%), penicillin (100% vs. 99.1%), amoxiclav (28.6% vs. 3.5%), linezolid (14.3% vs. 0.0%), ciprofloxacin (42.9% vs. 13.9%), and gentamicin (42.9% vs. 13.0%). The proportion of S. aureus isolates that were multidrug resistant was 37.7% (n = 46). We conclude that S. aureus was the predominant colonizer of the nasopharynx of the SCD children, warranting the continuous monitoring of this risk group for invasive S. aureus infections.

Clinical and microbial spectrum of community-acquired pneumonia in children of north India.

We compared the clinical, radiological and microbial profile in children suffering from community-acquired pneumonia in rural populations of north India. A total of 125 such children were divided into two age groups of 2-12 months (Group A) and 13-60 months (Group B). After taking a history and clinical examination, routine investigations including full blood count, blood, urine, and nasopharyngeal swab culture and radiology were performed. Multiplex polymerase chain reaction for Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae and Haemophilus influenzae was carried out. Failure to eat or drink was more common (40.9%) in Group A, than Group B (18.7%). Lung consolidation was more common in Group B. Blood and urine culture were found to be more positive in Group A while combined nasopharyngeal culture and multiplex polymerase chain reaction favoured more bacterial growth in Group B.

Nasopharyngeal colonization at birth and the development of early-onset neonatal sepsis

Background Neonatal sepsis is one of the major causes of morbidity and mortality in neonates. Exposure to maternal bacteria during pregnancy or delivery allows for colonization of the normal upper airway. Such bacteria become the major ecological species in the infant. If the colonizing bacteria invade the bloodstream, early-onset neonatal sepsis (EONS) could occur.&#x0D; Objective To evaluate for an association between colonization of the newborn nasopharynx and EONS, as well as for agreement between nasopharyngeal swab culture and blood culture isolate results.&#x0D; Methods This prospective cohort study was conducted in Dr. Wahidin Sudirohusodo General Hospital and Ibnu Sina Hospital, Makassar, South Sulawesi. Nasopharyngeal swab culture was taken within 2 hours of life from newborns who met the inclusion criteria, then they were followed up for signs of EONS. Blood culture was taken from subject with EONS.&#x0D; Results Of the 100 newborns, 69 (69%) had nasopharyngeal bacterial colonization, of whom 5.8% (4/69) experienced EONS. Of the remaining 31 (31%) without colonization, 9.7% (3/31) experienced EONS. There was no significant difference in frequency of EONS between newborns with and without nasopharyngeal colonization. Although Gram-negative bacteria were predominant among colonized newborns, there was no significant difference to numbers of Gram-positive bacteria as a causative agent of EONS. Only one patient with EONS had the same bacterial species in both the nasopharynx and blood culture isolate.&#x0D; Conclusion Newborn nasopharyngeal colonization at birth is not associated with EONS.

What is the role of Ewingella americana in humans? A case report in a healthy 4-year-old girl

BackgroundEwingella americana (Ea) is a Gram-negative, lactose-fermenting, oxidase-negative and catalase-positive bacterium that was first described in 1983 as a new genus and species in the family Enterobacteriaceae. It is not known whether Ea is a true pathogen or simply an opportunistic infectious agent, as most of the cases have been described in patients at risk.Case presentationA 4-year-old girl described here was hospitalized due to a productive cough over the previous 3 weeks and a fever > 38 °C associated with tachypnea over the previous 2 days. Her familial and personal medical histories were negative for relevant diseases, including respiratory infections. At admission, she was febrile (axillary temperature 39.2 °C) and had dyspnea with retractions, grunting and nasal flaring. A chest examination revealed fine crackling rales in the left upper field associated with bilateral wheezing. A chest X-ray revealed segmental consolidation of the lingula of the left lung. Laboratory tests revealed leukocytosis (15.,800 white blood cells/mm3 with 50.3% neutrophils), a slight increase in serum C-reactive protein (11.9 mg/L) and normal procalcitonin values (< 0.12 ng/mL). A nasopharyngeal swab culture did not reveal viral or bacterial respiratory pathogens, including atypical bacteria. A blood culture revealed the presence of a Gram-negative, lactose-fermenting rod that was oxidase negative and catalase positive. The isolate was identified by means of the VITEK®2 identification system (bioMérieux, Firenze, Italy) as Ea. This identification was confirmed by sequencing the 16 s ribosomal deoxyribonucleic acid (rDNA). The pathogen was sensitive to aminoglycoside, fluoroquinolones, carbapenems, cefotaxime, and ceftazidime but was intermediate against sulfametoxazole/trimethoprim and resistant to amoxicillin-clavulanic acid, fosfomycin, and oxacillin. The child was immediately treated orally with amoxicillin-clavulanic acid and erythromycin. Based on the results of a blood culture and sensitivity tests, the amoxicillin-clavulanic acid medication was stopped after 3 days. Erythromycin was continued for a total of 10 days, and the child was discharged after 3 days in the hospital. Follow-up visit 1 month later did not reveal any respiratory problems.ConclusionThis case shows that Ea infections in healthy subjects are mild even in pediatric age, and the need for antibiotic therapy is debated. Cases occurring in subjects with underlying chronic disease can be significantly more complicated and require appropriate antibiotic therapy.

Nasopharyngeal carriage of neisseria meningitidis among medical school students in Turkey.

Objective: Neisseria meningitidis can colonise healthy human nasopharynx and is one of the most important etiologic agent of epidemic meningitis. The purpose of this study is to investigate the carriage rate, serogroup distribution and antibiotic resistance of Neisseria meningitidis in medical faculty students. Methods: Nasopharyngeal swab cultures were evaluated. Identification is made by convensional and semi-otomatised system. Serogroup analysis was performed with slide agglutination method. Minimum inhibitor concentration results were evaluated by gradient test. Risk factors for carriage were investigated. Results: Neisseria meningitidis was isolated from 3 out of 475 (0.6%) students. Two of them were serogroup A and one was serogroup C. All strains were susceptible to penicillin and ceftriaxone. Living in a dormitory and sharing the room with three other students and smoking were found as risk factors. None of the students reported upper respiratory tract infection or antibiotic usage. Other potential pathogenic microorganisms colonising nasopharynx were also identified and most detected of them is methicillin susceptible Staphylococcus aureus (n: 87). Conclusion: Neisseria meningitidis is one of the leading pathogen in our country as it’s in the world. Since serogroups of isolated strains differ from region to region, it’s important that every country should conduct regular surveillance in order to utilize an effective vaccine for prevention and outbreak management against this infection.

167. A Bordetella pertussis Human Challenge Model Induces Immunizing Colonization in the Absence of Symptoms

Background Bordetella pertussis is one of the leading causes of vaccine preventable death and morbidity globally. Over the last 20 years, pertussis has resurged worldwide, even in territories with high immunization coverage. To improve vaccine strategies, a greater understanding of human B. pertussis infection and immunity is required. This study aims to develop a safe controlled human B. pertussis infection model and to define natural immune responses against wild-type B. pertussis in order to facilitate the development of bioassays and next-generation pertussis vaccines.MethodsIn this first-in-human controlled infection model, healthy volunteers aged 18–45 years with an anti-pertussis toxin (PT) IgG level of <20 IU/mL were inoculated intranasally with B. pertussis strain B1917. Safety, colonization, and shedding were monitored over a 17-day inpatient period. Colonization was assessed by culture and qPCR of nasal washes and nasopharyngeal swabs. Azithromycin eradication therapy was commenced on day 14. The dose of inoculum was escalated to optimize colonization rate, expressed as the percentage of volunteers colonized at any sampling point between day 3 and 14. The immunological response is being assessed at various time points over 1 year.Results24 volunteers were challenged in groups of 4–5. The dose was gradually escalated from 103 colony forming units (cfu) to 105 cfu. Colonization rate ranged from 0% (dose 103 cfu) to 80% (105 cfu). Amongst this initial cohort, no significant safety concerns or symptoms attributed to B. pertussis disease were reported. Eradication was achieved by 48 hours in 100% of colonized volunteers. At least 4-fold rise in anti-PT IgG by day 28 in comparison to baseline was observed in 5 out of 8 volunteers who had >1,000 cfu/mL viable B. pertussis in the nasal wash and in one volunteer without detectable colonization. Nasal wash cultures were more sensitive in detecting colonization than nasopharyngeal swab cultures. No shedding of B. pertussis was detected in systematically collected environmental samples.ConclusionThis is the first study to demonstrate safe deliberate induction of B. pertussis colonization. It shows that asymptomatic B. pertussis colonization occurs and causes a systemic immune response. The model that we have developed will be a valuable tool to further investigate B. pertussis colonization and vaccine development.Disclosures K. Kester, Sanofi: Employee, Salary. S. Faust, Pfizer, Merck, Sanofi, AstraZeneca/Medimmune: Scientific Advisor, all honoraria paid to institution with no personal payments of any kind.

Increased carriage of non-vaccine serotypes with low invasive disease potential four years after switching to the 10-valent pneumococcal conjugate vaccine in The Netherlands.

The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in The Netherlands in 2006 and was replaced by PHiD-CV10 in 2011. Data on carriage prevalence of S. pneumoniae serotypes in children and invasive pneumococcal disease (IPD) in children and older adults were collected to examine the impact of PCVs on carriage and IPD in The Netherlands. Pneumococcal carriage prevalence was determined by conventional culture of nasopharyngeal swabs in 24-month-old children in 2015/2016. Data were compared to similar carriage studies in 2005 (pre-PCV7 introduction), 2009, 2010/2011 and 2012/2013. Invasive pneumococcal disease isolates from hospitalized children <5 years and adults >65 years (2004–2016) were obtained by sentinel surveillance. All isolates were serotyped by Quellung. Serotype invasive disease potential was calculated using carriage and nationwide IPD data in children. The overall pneumococcal carriage rate was 48% in 2015/2016, lower than in 2010/2011 (64%) and pre-vaccination in 2005 (66%). Carriage of the previously dominant non-vaccine serotypes 19A and 11A has declined since 2010/2011, from 14.2% to 4.6% and 4.2% to 2.7%, respectively, whereas carriage of serotypes 6C and 23B has increased (4.2% to 6.7% and 3.9% to 7.3%), making serotypes 6C and 23B the most prevalent carriage serotypes. IPD incidence declined in children (20/100,000 cases in 2004/2006 to 6/100,000 cases in 2015/2016) as well as in older adults (63/100,000 cases to 51/100,000 cases). Serotypes 6C, 23B and 11A have high carriage prevalence in children, but show low invasive disease potential. Serotype 8 is the main causative agent for IPD in older adults (11.3%). In conclusion, 10 years after the introduction of pneumococcal vaccination in children in The Netherlands shifts in carriage and disease serotypes are still ongoing. Surveillance of both carriage and IPD is important to assess PCV impact and to predict necessary future vaccination strategies in both children and older adults.

Etiology and Risk Factors Determining Poor Outcome of Severe Pneumonia in Under-Five Children.

To determine the etiology of severe pneumonia (pneumonia with chest indrawing) in under-five children, and to study the risk factors for poor outcomes viz., 'treatment failure', 'need for change in antibiotics', 'prolonged hospital stay', 'need for mechanical ventilation' and 'mortality.' Children (age 2 mo to 5 y) with pneumonia and chest drawing were enrolled prospectively from October 2012 through September 2013. Clinical history was recorded, and examination, anthropometry and investigations (including chest X-ray, blood culture and nasopharyngeal swab culture) were performed. Children were managed as per standard guidelines, and recovery outcomes were recorded in form of 'treatment failure' (defined as persistence of features of severe pneumonia after 72h or worsening of clinical condition before 72h), need for change of antibiotics and prolonged (>5 d) hospital stay. The associations between the clinical, anthropometric and diagnostic risk factors and the recovery outcomes were evaluated by univariate and multivariate logistic regression analysis. Out of 120 children enrolled in the study, 36 (42%) were culture positive (nasopharyngeal/blood); most common bacteria isolated were Streptococcal pneumoniae and Staphylococcal aureus, respectively. Treatment failure was seen in 15 (12.5%), 34 (28.3%) needed change of antibiotics, and 50 (41.6%) children required prolonged hospitalization. Low birth weight, overcrowding, general danger signs (lethargy/unable to drink), clinical rickets, crepitation, leukocytosis and positive blood culture were significant risk factors for treatment failure, prolonged hospital stay and antibiotics change. On multivariate logistic regression analysis, respiratory rate of >70/min (OR 19.94, 95%CI 1.42-280.29), lethargy/unconsciousness (OR 114.2, 95%CI 3.14-4147.92), and positive blood culture (OR 15.24, 95%CI 2.53-91.67) had more chances of treatment failure. Duration of hospital stay was prolonged in those who had inability to drink (OR 3.89, CI 1.37-10.99) or abnormal chest X-ray (OR 8.45, CI 3.56-20.04). Children with rickets (OR 3.69, CI 1.14-11.96), and those with abnormal chest X-ray (OR 9.66, CI 2.62-35.53) had a higher odds of change in antibiotics. Presence of wheeze was a protective factor for treatment failure (OR 0.03, CI 0.00-0.37) and change of antibiotics (OR 0.24, CI 0.07-0.74). Staphylococcus aureus and Streptococcus pneumoniae are the predominant organisms causing severe pneumonia in our setting. Children with risk factors such as respiratory rate>70/min, rickets, lethargy/unconsciousness, not able to drink, abnormal chest X-ray or positive blood culture are likely to have a delayed recovery or need of change of antibiotics, whereas those with wheeze are likely to recover faster with less chances of treatment failure.

Efficacy of Recombinant Influenza Vaccine in Adults 50 Years of Age or Older

BackgroundImproved influenza vaccines are needed to control seasonal epidemics. This trial compared the protective efficacy in older adults of a quadrivalent, recombinant influenza vaccine (RIV4) with a standard-dose, egg-grown, quadrivalent, inactivated influenza vaccine (IIV4) during the A/H3N2-predominant 2014–2015 influenza season, when antigenic mismatch between circulating and vaccine influenza strains resulted in the reduced effectiveness of many licensed vaccines.MethodsWe conducted a randomized, double-blind, multicenter trial of RIV4 (45 μg of recombinant hemagglutinin [HA] per strain, 180 μg of protein per dose) versus standard-dose IIV4 (15 μg of HA per strain, 60 μg of protein per dose) to compare the relative vaccine efficacy against reverse-transcriptase polymerase-chain-reaction (RT-PCR)–confirmed, protocol-defined, influenza-like illness caused by any influenza strain starting 14 days or more after vaccination in adults who were 50 years of age or older. The diagnosis of influenza infection was confirmed by means of RT-PCR assay and culture of nasopharyngeal swabs obtained from participants with symptoms of an influenza-like illness. The primary end point was RT-PCR–confirmed, protocol defined, influenza-like illness between 14 days or more after vaccination and the end of the influenza season.ResultsA total of 9003 participants were enrolled and underwent randomization; 8855 (98.4%) received a trial vaccine and underwent an efficacy follow-up (the modified intention-to-treat population), and 8604 (95.6%) completed the per-protocol follow-up (the modified per-protocol population). Among RIV4 recipients, the RT-PCR–confirmed influenza attack rate was 2.2% (96 cases among 4303 participants) in the modified per-protocol population and 2.2% (96 cases among 4427 participants) in the modified intention-to-treat population. Among IIV4 recipients, the attack rate was 3.2% (138 cases among 4301 participants) in the modified per-protocol population and 3.1% (138 cases among 4428 participants) in the modified intention-to-treat population. A total of 181 cases of influenza A/H3N2, 47 cases of influenza B, and 6 cases of nonsubtypeable influenza A were detected. The probability of influenza-like illness was 30% lower with RIV4 than with IIV4 (95% confidence interval, 10 to 47; P=0.006) and satisfied prespecified criteria for the primary noninferiority analysis and an exploratory superiority analysis of RIV4 over IIV4. The safety profiles of the vaccines were similar.ConclusionsRIV4 provided better protection than standard-dose IIV4 against confirmed influenza-like illness among older adults. (Funded by Protein Sciences; ClinicalTrials.gov number, NCT02285998.)

(491) - Community Acquired Respiratory Viral Infection after Lung Transplantation: BOS Risk and Risks of Specific Viruses

Community acquired respiratory viral (CARV) infections are a reported risk factor for bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx) but the risk of specific viral infections is unknown. We assessed the risk of specific CARV for BOS and death after LTx. Retrospective, single-centre analysis of 380 LTx recipients 01/2003- 01/2013, (BLTx 318, SLTx 18, HLTx 11),(CF 81, IPF 61, COPD 107, A1AT 29, PAH 12, CHD 9, ILD 21, B 21, OB 6). 33 were excluded for insufficient data, survival < 90 days, or retransplantation. Data were collected through 07/2013 with a mean +/- SD (range) follow up of 1473±1029 (107-3776) days. 225/347 had 487 symptomatic CARV infections confirmed by direct fluorescence antigen, PCR or viral culture of nasopharyngeal swabs and/or bronchoalveolar lavage. Standard therapeutic protocols were followed for specific viruses. Univariate and multivariate time-dependent Cox models were used. CARV included 76 Parainfluenza virus (PIV), 82 Respiratory Syncytial virus (RSV), 5 Adenovirus (AV), 25 Human metapneumovirus (HMPV), 46 Influenza A (FluA), 12 Influenza B (FluB), and 241 Picornavirus (PRNA). Analysed as a time dependent variable initial CARV (PIV =37, RSV=47, AV=3, HMPV=6, FluA=24, FluB=7,PRNA=101) were a significant risk factor for BOS (HR 1.46 95%CI 1.06-2.01, p=0.02) but not death (HR 1.39 95%CI 0.94-2.03, p=0.10). Risk was not dependent on type of CARV (p=0.56, log rank) or stratification by antecedent rejection history (p=0.16, log rank). Biopsy proven rejection remained a significant independent risk factor for BOS (HR 1.23 95%CI 1.03-1.48, p=0.02) and BOS was the major risk for death (HR 7.73 95%CI 5.05-11.84, p<0.001). Symptomatic CARV infection is a significant risk factor for BOS but not death and the risk is independent of viral species or prior rejection episodes. Modification of natural history by antiviral therapy may explain in part the similarity of outcomes shown for specific viruses.

Isolation Of Potential Pathogenic Bacteria From Nasopharynx From Patients Having Cough For More Than Two Weeks.

This cross sectional study was done from January 2009 to June 2010 in Microbiology department of Dhaka Medical College on isolation of potential pathogenic bacteria from nasopharynx from patients having cough for more than two weeks. The nasopharyngeal swabs were collected from 290 patients for culture and 101 blood samples were collected for slide agglutination test against anti- Bordetella antibody. In case of culture of nasopharyngeal swabs, 117 (73.12%) samples yielded growth of single organism, 16 (10%) yielded mixed growth and 27 (16.88%) samples yielded no growth in children. In adults, 85 (65.39%) samples yielded growth of single organism, 1 (0.77%) yielded mixed growth and 44 (33.84%) samples yielded no growth. Highest incidence (33.33%) of S. pneumoniae was found in age group of 1-5 years, highest incidence (32.20%) of N. meningitidis was found in age group of 18-25 years and highest incidence (32%) of Staph. aureus was found in age group of 25-50 years. One (0.63%) B. pertussis was isolated from a child and 5 (3.84%) B. parapertussis were isolated from adults. In this study, 116 (83.45%) samples yielded growth in lower socioeconomic group and 101 (70.62%) yielded growth in the samples of middle socioeconomic group. Among the study participants, 31(30.70%) were positive and 70 (69.30%) were negative for antibody against B. pertussis. In anti-Bordetella antibody positive cases, 14 (93.33%) children had duration of cough for 2-3 weeks, 7 (43.75%) adults had duration of cough for 3-4 weeks and 1 (6.25%) adults had more than 6 weeks.DOI: http://dx.doi.org/10.3329/bjmm.v4i2.10826

Clinical and Microbiological Evaluation of Travel-Associated Respiratory Tract Infections in Travelers Returning From Countries Affected by Pandemic A(H1N1) 2009 Influenza

BackgroundAlthough acute respiratory tract infections (RTI) have been recognized as a significant cause of illness in returning travelers, few studies have specifically evaluated the etiologies of RTI in this population.MethodsThis prospective investigation evaluated travelers returning from countries with endemic influenza A(H1N1) 2009, and who were seen in our department at the onset of the outbreak (April–July 2009). Patients were included if they presented with signs of RTI that occurred during travel or less than 7 days after return from overseas travel. Patients were evaluated for microbial agents with RespiFinder plus assay, and throat culture according to clinical presentation.ResultsA total of 113 travelers (M/F ratio 1.2:1; mean age 39 y) were included. They were mainly tourists (n = 50; 44.2%) mostly returning from North America (n = 65; 58%) and Mexico (n = 21; 18.5%). The median duration of travel was 23 days (range 2–540 d). The median lag time between return and onset of illness was 0.2 days (range 10 d prior to 7 d after). The main clinical presentation of RTI was influenza‐like illness (n = 76; 67.3%). Among the 99 microbiologically evaluated patients, a pathogen was found by polymerase chain reaction (PCR) or throat culture in 65 patients (65.6%). The main etiological agents were influenza A(H1N1) 2009 (18%), influenza viruses (14%), and rhinovirus (20%). A univariate analysis was unable to show variables associated with influenza A(H1N1) 2009, whereas rhinorrhea was associated with viruses other than influenza (p = 0.04).ConclusionDespite the A(H1N1) 2009 influenza pandemic, rhinovirus and other influenza viruses were also frequent causes of RTI in overseas travelers. Real‐time reverse transcription‐PCR and nasopharyngeal swab cultures are useful diagnostic tools for evaluating travelers with RTI.

Absence of fetal transmission of H1N1 despite severe maternal infection

To the editor: Influenza infection displays a spectrum of clinical severity dependent upon host immune status and viral strain. The outbreak of H5N1 in humans has been accompanied by both severe pneumonia and viral spread beyond the lung. In 2007, a postmortem study of two adults and one fetus infected with H5N1 1 demonstrated infection of lung, liver, small intestine, brain, and placenta indicating transmission across the placenta. The recent H1N1 pandemic 2 has been notable for the involvement of young, healthy adults. We recently observed an H1N1 infection in a pregnant 26‐year‐old female that led to severe maternal disease and spontaneous abortion. The patient presented to the emergency room (ER) with acute onset of upper respiratory infection (URI). She had been in a state of good health without significant past medical history except for a pregnancy of approximately 16 weeks. The patient and her significant other had developed nasal congestion, cough, and fever the previous day. Medical evaluation confirmed the URI but a chest X‐ray showed no evidence of bacterial infection. Given the severity of infection and systemic signs and symptoms, there was concern for possible influenza infection. Nasopharyngeal swabs were sent for viral culture, Tamiflu was prescribed, acetaminophen was administered, and the patient was discharged. Two days later the patient returned to the ER with complaints of worsening URI, now accompanied by more severe myalgias, headaches, diarrhea, and elevated heart rate (pulse 175). On questioning, the patient indicated she had not been able to afford the Tamiflu prescription so she had only taken acetaminophen at home. The patient was placed on nasal oxygen. Despite aggressive therapy, receiving 4 l of intravenous fluids, her pulse rate decreased only minimally. The patient was started on antibiotics and Tamiflu, but within 3 hours she spontaneously aborted her fetus. Four days after her initial ER visit the patient’s nasopharyngeal swab culture grew Influenza A, swine origin 2009 A (H1N1). The patient continued to do poorly and developed adult respiratory distress syndrome (ARDS) requiring aggressive intervention. After 2 weeks, evaluation of acute neurological deterioration demonstrated multifocal hypoattenuated lesions on head CT scan. She was diagnosed with “influenza encephalitis” but no CSF tap was performed because of suspected increased intracranial pressure for which she was treated with steroids, mannitol, and Lasix. Her neurological condition stabilized, and after 1 month of hospitalization she was discharged to a chronic care facility. Pathological examination demonstrated a 470 g second trimester placenta with severe acute deciduitis. By weights and measures, the abortus was estimated to be 15‐week gestation. No systemic or CNS histopathology was observed. Extensive immunohistochemical and in situ hybridization with S35 labeled probes for influenza demonstrated no evidence of infection in any systemic organ or the CNS. Nucleic acids were extracted from paraffin blocks of H1N1 (A/Mexico/4108/09) infected mouse lung and the human placenta, umbilical cord, and fetal organs (cerebral cortex, cerebellum, lung, liver, heart, and spleen) then assessed with PCR for H1N1 sequences. H1N1 sequences were detected in the positive mouse control but not the human tissues. In summary, this 26‐year‐old female suffered severe H1N1 infection with CNS complications. Three to 4 days after symptom onset, she spontaneously aborted a 15‐week fetus that showed no evidence of influenza infection. Therefore despite severe maternal infection, H1N1 did not transmit across the human placenta during acute infection as has been reported with H5N1 infection.

The Clinical Significance of Nasopharyngeal Carriages in Immunocompromised Children as Assessed

Background: The aim of this study was to determine the prevalence of asymptomatic nasopharyngeal carriages in immunocompromized children by using a multiplex reverse transcriptase-polymerase chain reaction (mRT-PCR) assay kit. Methods: We obtained clinical samples by nasopharyngeal swabs from 42 patients with underlying immune deficiency from May 20, 2008 to May 22, 2008. The children were free from signs of respiratory tract infections at the time of sampling. Isolated cDNA was extracted and after this the DNA was examined using a multiplex primer set for pneumonial bacteria detection (SeeplexR PneumoBacter ACE Detection, Seegene, Seoul, Korea). The amplified PCR products were separated on 2% agarose gels and stained with ethidium bromide and a screentape system (Lab901, Scottland, UK) and then they were compared. The nasopharyngeal swab culture was done simultaneously and this was compared with the results of mRT-PCR. Results: A total of 42 patients (males: 24, females: 18) aged between 1.2 and 16.3 years (median: 9.2 years) were included in this study. The mRT-PCR detected bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Chlamydia pneumoniae, and Bordetella pertussis) in 28 patients (66.6%). Of these 28 patients, 4 patients (14.3%) showed more than 2 bacteria: 2 patients were positive for two bacteria (S. pneumoniae and H. influenzae, H.influenzae and B. pertussis) and 2 patients were positive for three bacteria (S. pneumoniae, B. pertussis and C. pneumoniae, C. Pneumoniae, H. influenzae and B. pertussis). S. pneumoniae was cultured in one patient (2.4%). Conclusions: The mRT-PCR is a sensitive tool for the detection of the asymptomatic nasopharyngeal carriages. The clinical significance of the bacteria detected in immunocompromized patients by mRT-PCR will need further evaluation. (Korean J Hematol 2009;44:220-226) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

Microbiological etiology in clinically diagnosed community-acquired pneumonia in primary care in Örebro, Sweden

To study the etiology of clinically diagnosed community-acquired pneumonia (CAP) in antibiotically naive patients attending a primary care center and treated at their homes. A three-year prospective study was carried out, and 177 patients presenting with clinical signs of CAP were included. All patients had chest X-rays after inclusion, and 82 (46%) showed infiltrates. Nasopharyngeal swab culture was performed on all patients, and 51% produced a representative sputum sample. Paired sera were obtained from 176 patients. Among the 82 patients with radiographically proven CAP, Streptococcus pneumoniae was detected in 26 patients (32%), Haemophilus influenzae in 23 (28%), Mycoplasma pneumoniae in 15 (18%), and Chlamydia pneumoniae in four (5%). Serologic evidence of a viral infection was found in 13 patients (16%). Among the 95 patients without infiltrates, S. pneumoniae was found in 21 (22%), H. influenzae in 14 (15%), M. pneumoniae in two (2%), and C. pneumoniae in five (5%). Viral infection was detected in 19 (20%) of these 95 patients. In primary care in Sweden, the initial antibiotic treatment in any patient with pneumonia should be effective against S. pneumonia and H. influenzae. In addition, M. pneumoniae should be targeted during recurrent epidemics. C. pneumoniae, and especially Legionella, seem to be uncommon in primary care.