Role of procalcitonin and C-reactive protein in differentiation of mixed bacterial infection from 2009 H1N1 viral pneumonia

Please cite this paper as: Ahn et al. (2011) Role of procalcitonin and C‐reactive protein in differentiation of mixed bacterial infection from 2009 H1N1 viral pneumonia. Influenza and Other Respiratory Viruses 5(6), 398–403. Background Mixed bacterial infection is an important contributor to morbidity and mortality during influenza pandemics. We evaluated procalcitonin (PCT) and C‐reactive protein (CRP) in differentiating pneumonia caused by mixed bacterial and 2009 H1N1 influenza infection from 2009 H1N1 influenza infection alone. Methods Data were collected retrospectively over a 7‐month period during the 2009 H1N1 influenza pandemic. Patients visiting emergency department and diagnosed as community‐acquired pneumonia caused by 2009 H1N1 infection were included (n = 60). Results Mixed bacterial and viral infection pneumonia (n = 16) had significantly higher PCT and CRP levels than pneumonia caused by 2009 H1N1 influenza alone (n = 44, P = 0·019, 0·022 respectively). The sensitivity and specificity for detection of mixed bacterial infection pneumonia was 56% and 84% for PCT > 1·5 ng/ml, and 69% and 63% for CRP > 10 mg/dl. Using PCT and CRP in combination, the sensitivity and specificity were 50% and 93%, respectively. Conclusion Procalcitonin and CRP alone and their combination had a moderate ability to detect pneumonia of mixed bacterial infection during the 2009 H1N1 pandemic. Considering high specificity, combination of low CRP and PCT result may suggest that pneumonia is unlikely to be caused by mixed bacterial infection.     

Clinical, laboratory and radiologic characteristics of 2009 pandemic influenza A/H1N1 pneumonia: primary influenza pneumonia versus concomitant/secondary bacterial pneumonia

Please cite this paper as: Song et al. (2011). Clinical, laboratory and radiologic characteristics of 2009 pandemic influenza A/H1N1 pneumonia: primary influenza pneumonia versus concomitant/secondary bacterial pneumonia. Influenza and Other Respiratory Viruses 5(6), e535–e543. Background Although influenza virus usually involves the upper respiratory tract, pneumonia was seen more frequently with the 2009 pandemic influenza A/H1N1 than with seasonal influenza. Methods From September 1, 2009, to January 31, 2010, a specialized clinic for patients (aged ≥15 years) with ILI was operated in Korea University Guro Hospital. RT‐PCR assay was performed to diagnose 2009 pandemic influenza A/H1N1. A retrospective case–case–control study was performed to determine the predictive factors for influenza pneumonia and to discriminate concomitant/secondary bacterial pneumonia from primary influenza pneumonia during the 2009–2010 pandemic. Results During the study period, the proportions of fatal cases and pneumonia development were 0·12% and 1·59%, respectively. Patients with pneumonic influenza were less likely to have nasal symptoms and extra‐pulmonary symptoms (myalgia, headache, and diarrhea) compared to patients with non‐pneumonic influenza. Crackle was audible in just about half of the patients with pneumonic influenza (38·5% of patients with primary influenza pneumonia and 53·3% of patients with concomitant/secondary bacterial pneumonia). Procalcitonin, C‐reactive protein (CRP), and lactate dehydrogenase were markedly increased in patients with influenza pneumonia. Furthermore, procalcitonin (cutoff value 0·35 ng/ml, sensitivity 81·8%, and specificity 66·7%) and CRP (cutoff value 86·5 mg/IU, sensitivity 81·8%, and specificity 59·3%) were discriminative between patients with concomitant/secondary bacterial pneumonia and patients with primary influenza pneumonia. Conclusions Considering the subtle manifestations of 2009 pandemic influenza A/H1N1 pneumonia in the early stage, high clinical suspicion is required to detect this condition. Both procalcitonin and CRP would be helpful to differentiate primary influenza pneumonia from concomitant/secondary bacterial pneumonia.     

Clinical epidemiology comparison of H1N1 RT-PCR-positive and RT-PCR-negative pneumonia during the 2009-2010 pandemic in Mansoura University hospitals, Egypt

Please cite this paper as: Ahmed et al. (2011) Clinical epidemiology comparison of H1N1 RT‐PCR‐positive and RT‐PCR‐negative pneumonia during the 2009–2010 pandemic in Mansoura University hospitals, Egypt. Influenza and Other Respiratory Viruses 5(4), 241–246 Background Worldwide, the infectivity and disease burden of the H1N1 pandemic were overestimated because of limited clinical experience concerning patient presentation and outcome of those infected with the novel H1N1 virus. Objective This study aimed to compare the epidemiologic clinical data among H1N1 RT‐PCR‐positive and RT‐PCR‐negative pneumonic patients during the 2009–2010 pandemic in Mansoura University Hospitals, Egypt. Methods A record‐based, case–control study was conducted for 43 adult patients admitted to the chest department isolation unit with community‐acquired pneumonia during the 2009–2010 H1N1 pandemic after reviewing of 198 suspected and confirmed H1N1 hospitalized cases. Of these patients, 20 cases were confirmed to be H1N1‐positive using an RT‐PCR detection technique. The remaining 23 patients were RT‐PCR‐negative. Demographic, clinical, laboratory and radiological data were collected and analyzed using spss version 11. Results A review of 198 hospital case records for revealed one main peak of H1N1 influenza during the last week of December 2009. Pneumonic patients who were H1N1‐positive were more likely to present with sore throat (P = 0·005), dyspnea (P = 0·002), and gastrointestinal (GIT) complaints (vomiting and diarrhea P = 0·02) when compared to the H1N1‐negative group. Also, complications were significantly more frequent (P = 0·01) in the H1N1‐confirmed group than in the non‐confirmed group. However, no significant differences were found between the groups regarding length of hospital stay, intensive care unit (ICU), and admission or mortality. Conclusion Sore throat, dyspnea, and presence of GIT complaints increase the suspicion of H1N1 positivity in pneumonia acquired during an H1N1 pandemic. However, H1N1 did not worsen the disease burden of pneumonia.     

Bronchoscopic findings in a child with pandemic novel H1N1 influenza A and methicillin-resistant Staphylococcus aureus

The spectrum of disease with pandemic novel H1N1 influenza A (2009) virus ranges from non-febrile, mild upper respiratory tract infection to severe or fatal pneumonia. We report the bronchoscopic findings associated with a fatal case of H1N1 influenza A associated with co-infection with methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy child, which were more severe than those previously described as associated with seasonal influenza infection alone. The severity of the airway pathology seen on bronchoscopy in this patient may be due to a unique effect of the H1N1 influenza A virus or may be as a result of a destructive synergism between this virus and bacteria such as MRSA.     

The first cases of 2009 pandemic influenza A (H1N1) virus infection in the United States: a serologic investigation demonstrating early transmission

Please cite this paper as: Fry et al. (2012) The first cases of 2009 pandemic influenza A (H1N1) virus infection in the United States: a serologic investigation demonstrating early transmission. Influenza and Other Respiratory Viruses 6(3), e48–e53. Background The first two laboratory‐confirmed cases of 2009 pandemic influenza A (H1N1) virus (H1N1pdm09) infection were detected in San Diego (SD) and Imperial County (IC) in southern California, April 2009. Objectives To describe H1N1pdm09 infections and transmission early in the 2009 H1N1 pandemic. Patients/Methods We identified index case‐patients from SD and IC with polymerase chain reaction (PCR)‐confirmed H1N1pdm09 infections and investigated close contacts for a subset of case‐patients from April 17–May 6, 2009. Acute and convalescent serum was collected. Serologic evidence for H1N1pdm09 infection was determined by microneutralization and hemagglutination inhibition assays. Results Among 75 close contacts of seven index case‐patients, three reported illness onset prior to patient A or B, including two patient B contacts and a third with no links to patient A or B. Among the 69 close contacts with serum collected >14 days after the onset of index case symptoms, 23 (33%) were seropositive for H1N1pdm09, and 8 (35%) had no fever, cough, or sore throat. Among 15 household contacts, 8 (53%) were seropositive for H1N1pdm09. The proportion of contacts seropositive for H1N1pdm09 was highest in persons aged 5–24 years (50%) and lowest in persons aged ≥50 years (13%) (P = 0·07). Conclusions By the end of April 2009, before H1N1pdm09 was circulating widely in the community, a third of persons with close contact to confirmed H1N1pdm09 cases had H1N1pdm09 infection in SD and IC. Three unrelated clusters during March 21–30 suggest that transmission of H1N1pdm09 had begun earlier in southern California.     

Emergence of 2009A/H1N1 cases in a tertiary care hospital in New Delhi, India

Please cite this paper as: Broor et al. (2011) Emergence of 2009A/H1N1 cases in a tertiary care hospital in New Delhi, India. Influenza and Other Respiratory Viruses 5(6), e552–e557. Objective To determine virologic and epidemiologic characteristics of pandemic (H1N1) 2009 at All India Institute of Medical Sciences (AIIMS) a tertiary care hospital in New Delhi, India. Methods Nasal and throat swabs from patients with febrile acute respiratory illness (FARI) from August to December 2009 (n = 1401) were tested for 2009A/H1N1 and seasonal influenza A viruses by real‐time RT‐PCR. Results Of 1401 samples tested, 475 (33·9%) were positive for influenza A, of these majority (412; 87%) were 2009A/H1N1, whereas the remaining 63 (13%) were seasonal influenza A (49 were A/H3 and 14 were A/H1). While co‐circulation of 2009A/H1N1 and A/H3 was observed in August–September, subsequent months had exclusive pandemic influenza activity (October–December 2009). Pandemic 2009A/H1N1 emergence did not follow typical seasonal influenza seasonality in New Delhi, which normally peaks in July–August, but instead showed bimodal peaks in weeks 39 and 48 in 2009. The percent of specimens testing positive for 2009A/H1N1 influenza virus was found to be highest in >5‐ to 18‐year age group (41·2%; OR = 2·3; CI = 1·6–3·2; P = 0·00). Conclusions Taken together, our data provide high prevalence of pandemic 2009A/H1N1 in urban New Delhi with bimodal peaks in weeks 39 and 48 and highest risk group being the children of school‐going age (aged >5–18).     

Influenza A/H1N1 2009 pneumonia in kidney transplant recipients: characteristics and outcomes following high‐dose oseltamivir exposure

S.P. Watcharananan, T. Suwatanapongched, P. Wacharawanichkul, W. Chantratitaya, V. Mavichak, S.B. Mossad. Influenza A/H1N1 2009 pneumonia in kidney transplant recipients: characteristics and outcomes following high‐dose oseltamivir exposure.
Transpl Infect Dis 2010: 12: 127–131. All rights reserved Abstract: We report 2 cases of severe pneumonia due to the novel pandemic influenza A/H1N1 2009 in kidney transplant recipients. Our patients initially experienced influenza‐like illness that rapidly progressed to severe pneumonia within 48 h. The patients became hypoxic and required non‐invasive ventilation. The novel influenza A/H1N1 2009 was identified from their nasal swabs. These cases were treated successfully with a relatively high dose of oseltamivir, adjusted for their renal function. Clinical improvement was documented only after a week of antiviral therapy. Despite early antiviral treatment, we showed that morbidity following novel pandemic influenza A/H1N1 2009 infection is high among kidney transplant recipients.     

H1N1 infection in a cohort of hematopoietic stem cell transplant recipients: prompt antiviral therapy might be life saving

E. Suyani, Z. Aki, Ö. Güzel, ?. Altindal, E. ?enol, G. Sucak. H1N1 infection in a cohort of hematopoietic stem cell transplant recipients: prompt antiviral therapy might be life saving.
Transpl Infect Dis 2011: 13: 208–212. All rights reserved Abstract: Influenza A H1N1 virus, causing a pandemic since spring 2009, has been an important cause of morbidity and mortality worldwide. Patients with hematological malignancies and hematopoietic stem cell transplant (HCT) recipients are in a high‐risk group and might require hospitalization more commonly because of H1N1 infection. Early demonstration of H1N1 influenza virus and commencing antiviral therapy promptly can be life saving particularly in immunosuppressed patients. We retrospectively reviewed the data of 10 HCT recipients who were diagnosed with influenza H1N1 infection at the Stem Cell Transplantation Unit of Gazi University Hospital in Turkey, from October through December 2009. All patients, except 1, were started empirically on oseltamivir on admission, after nasopharyngeal and oropharyngeal sampling for H1N1 virus. Four of the patients, 2 of whom developed pneumonia, required hospitalization. One of the patients with pneumonia died of respiratory failure caused by bacterial co‐infection. The course of the remaining patients was uneventful. In conclusion, HCT recipients infected with H1N1 during the influenza H1N1 pandemic did not necessarily have an adverse prognosis, particularly with prompt administration of the appropriate antiviral therapy.     

Community‐acquired,methicillin‐resistant Staphylococcus aureus isolated from children with community‐onset pneumonia in China

Community‐acquired, methicillin‐resistant Staphylococcus aureus (CA‐MRSA) has been associated with morbidity and mortality in various countries. In this study, we characterized the molecular and clinical features of pediatric CA‐MRSA pneumonia in China. Between June 2006 and February 2008, 55 previously healthy children confined in eight hospitals countrywide were found to be afflicted with CA‐MRSA pneumonia. A total of 55 strains collected from these children were analyzed by multilocus sequence typing (MLST), Staphylococcus cassette chromosome mec (SCCmec) typing, and spa typing. The Panton–Valentine leukocidin (PVL) gene was also detected. Overall, nine STs were obtained, with ST59 (40.4%) established to be the most prevalent type. We first registered the new ST1409 from a child with necrotizing pneumonia. SCCmecIVa was the most predominant type, followed by SCCmec type V. Twelve spa types were identified, of which one new spa type, t5348, was first detected and registered. One typical livestock‐associated spa type, t034, was found in a 4‐month‐old girl living in the countryside. We also found that 40% of those isolates were PVL‐positive. In addition, the median age of the children in this study was 10 months. A total of 69% (38/55) of the children with community‐acquired pneumonia (CAP) had preceding influenza or influenza‐like illness, and three ST910‐MRSA‐IV strains (PVL gene‐positive) were associated with severe necrosis. The results indicated that the recent CA‐MRSA found in Chinese children with CAP was largely associated with the spread of the ST59‐MRSA‐IV clone, and most of the PVL‐positive strains in this study did not cause necrotic cases. Pediatr Pulmonol. 2010; 45:387–394. © 2010 Wiley‐Liss, Inc.     

Influenza A H1N1 in HIV-infected adults

Objectives

HIV‐infected adults are considered to be at higher risk for influenza A H1N1 complications but data supporting this belief are lacking. We aimed to compare epidemiological data, clinical characteristics, and outcomes of influenza A H1N1 infection between HIV‐infected and ‐uninfected adults.

Methods

From 26 April to 6 December 2009, each adult presenting with acute respiratory illness at the emergency department of our institution was considered for an influenza A H1N1 diagnosis by specific multiplex real‐time polymerase chain reaction. For every HIV‐infected adult diagnosed, three consecutive adults not known to be HIV‐infected diagnosed in the same calendar week were randomly chosen as controls.

Results

Among 2106 adults tested, 623 (30%) had influenza A H1N1 infection confirmed. Fifty‐six (9%) were HIV‐positive and were compared with 168 HIV‐negative controls. Relative to HIV‐negative controls, HIV‐positive patients were older, more frequently male, and more frequently smokers (P≤0.02). In the HIV‐positive group, prior or current AIDS‐defining events were reported for 30% of patients, 9% and 30% had CD4 counts of <200 and 200–500 cells/μL, respectively, and 95% had HIV‐1 RNA <50 copies/mL. Pneumonia (9%vs. 25%, respectively, in the HIV‐positive and HIV‐negative groups; P=0.01) and respiratory failure (9%vs. 21%, respectively; P=0.04) were less common in the HIV‐positive group. Oseltamivir (95%vs. 71% in the HIV‐positive and HIV‐negative groups, respectively; P=0.003) was administered more often in HIV‐positive patients. Three patients (all HIV‐negative) died. In the HIV‐positive group, CD4 cell count and plasma HIV‐1 RNA did not differ before and 4–6 weeks after influenza A H1N1 diagnosis (P>0.05).

Conclusions

HIV infection did not increase the severity of influenza A H1N1 infection, and influenza A H1N1 infection did not have a major effect on HIV infection.     

Clinical factors predictive of PCR positive in pandemic H1N1 2009 influenza virus infection

Please cite this paper as: Phungoen et al. (2011) Clinical factors predictive of PCR positive in pandemic H1N1 2009 influenza virus infection. Influenza and Other Respiratory Viruses 5(6), e558–e562. Objective Pandemic H1N1 2009 influenza virus (H1N1) has been spreading globally. Clinical features might be predictive and may be different among countries. Even though the PCR test is a confirmatory test for this viral infection, it is expensive and limited in most Thai health care facilities. We studied predictive factors of PCR positive in H1N1 suspected patients. Methods Consecutive patients who had influenza‐like illness less than seven days and had been tested for H1N1 by the real‐time PCR method between May and July 2009 were enrolled. Clinical data was collected and compared between those who had positive and negative PCR tests. Results There were 6494 patients had flu‐like symptoms. Of those, 166 patients were done PCR test and 75 patients (45·18%) had positive PCR test. There were four predictors for positive PCR test including history of contact with confirmed H1N1 patients, headache, body temperature, and coryza with the adjusted odds ratio (95% confidence interval) of 2·84 (1·09–7·40), 6·25 (1·42–27·49), 1·69 (1·08–2·66), and 0·31 (0·12–0·79), respectively. Conclusions Clinical factors can be both suggestive and protective factors for H1N1 infection. These factors may be helpful in clinical practice to assess the possibility of the H1N1 infection in people who are at risk; particularly in resource‐limited health care facilities.     

Swine influenza (H1N1) pneumonia in hospitalized adults: chest film findings

In patients with swine influenza (H1N1) pneumonia, the admission chest film is critical to rapidly detect simultaneous bacterial pneumonia due to Staphylococcus aureus or subsequent bacterial pneumonia due to Streptococcus pneumoniae or Haemophilus influenzae by the presence of focal infiltrates. Our objective was to characterize the chest film findings in 25 adults hospitalized with H1N1 pneumonia during the pandemic and detect focal infiltrates indicative of bacterial coinfection, that is, bacterial pneumonia. Chest films were obtained on admission, after 48 hours, and thereafter as indicated throughout hospitalization. Chest film findings were classified as no infiltrates, clear with accentuated bibasilar lung markings, or focal segmental/lobar infiltrates. The presence or absence of pleural effusion and cavitation was also noted. Admitted adults with H1N1 pneumonia had negative chest films or accentuated basilar lung markings. After 48 hours, 13% of patients developed patchy bilateral interstitial infiltrates. No patients had or subsequently developed focal segmental/lobar infiltrates indicative of bacterial community-acquired pneumonia during hospitalization. The most common chest film finding was no infiltrates or an accentuation of bibasilar lung markings in hospitalized adults with H1N1 pneumonia. No patients had focal segmental/lobar infiltrates indicative of superimposed bacterial community-acquired pneumonia.     

Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine

Please cite this paper as: Deng et al. (2012). Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine. Influenza and Other Respiratory Viruses 6(3), e42–e47. Background Swine have receptors for both human and avian influenza viruses and are a natural host for influenza A viruses. The 2009 influenza A(H1N1) pandemic (H1N1pdm) virus that was derived from avian, human and swine influenza viruses has infected pigs in various countries. Objectives To investigate the relationship between the H1N1pdm viruses isolated from piggery outbreaks in Australia and human samples associated with one of the outbreaks by phylogenetic analysis, and to determine whether there was any reassortment event occurring during the human‐pig interspecies transmission. Methods Real‐time RT‐PCR and full genome sequencing were carried out on RNA isolated from nasal swabs and/or virus cultures. Phylogenetic analysis was performed using the Geneious package. Results The influenza H1N1pdm outbreaks were detected in three pig farms located in three different states in Australia. Further analysis of the Queensland outbreak led to the identification of two distinct virus strains in the pigs. Two staff working in the same piggery were also infected with the same two strains found in the pigs. Full genome sequence analysis on the viruses isolated from pigs and humans did not identify any reassortment of these H1N1pdm viruses with seasonal or avian influenza A viruses. Conclusions This is the first report of swine infected with influenza in Australia and marked the end of the influenza‐free era for the Australian swine industry. Although no reassortment was detected in these cases, the ability of these viruses to cross between pigs and humans highlights the importance of monitoring swine for novel influenza infections.     

Clinical features of the hospitalized patients with 2009 pandemic influenza A (H1N1) in Santa Fe,Argentina

Background During 2009 occurred the emergence and global spread of a novel influenza A (H1N1) virus. We describe the clinical and epidemiologic features of hospitalized patients who survived and patients who died because of pandemic 2009 influenza A (H1N1) infection reported in Santa Fe, Argentina, from May to July 2009. Methods Using medical charts, we collected data on 242 patients who were hospitalized with confirmed laboratory results (defined as positive by specific PCR for pandemic 2009 influenza A H1N1). Results During the study period, there were 242 cases of hospitalization or death. Of the 242, 46% were admitted to an intensive care unit (ICU) and 33·5% died. The mean age was 27·8 years for surviving and 39·6 for those who died. Twenty‐eight percent of hospitalizations involved persons under the age of 15 years; 33% of the patients were between the age of 15 and 44 years; and only 3·3% were 65 years of age or older. Sixty‐seven percent had an underlying medical conditions, including diabetes, obesity, heart and lung diseases, and pregnancy. Of the 242 patients, 68% had findings consistent with pneumonia. Treatment with oseltamivir was administered to 227 (93 · 8%) patients from which 38 received oseltamivir within 48 hours after the onset of symptoms. Conclusions The pandemic strain caused severe illness, including pneumonia and acute respiratory distress syndrome, and resulted in ICU admissions in 46% of patients and death in 33·5%. The mean age of hospitalized infected cases was lower than is common with seasonal influenza. Underlying medical conditions were common in the 67% the evaluated patients. Patients who died had a higher prevalence of comorbidities (86·4%) than those who survived (57%), suggesting that the presence of chronic illness may increase the likelihood of death. However, the severe illness was also identified among young, healthy persons.     

Asthma and severity of the 2009 novel H1N1 influenza: a case-control study

Objective: Previous studies reported that the most common chronic condition found among hospitalized patients due to the novel 2009 H1N1 influenza was asthma. However, these studies did not include a concurrent control group. Thus, we investigated the association of asthma status and severity of H1N1 influenza in adults. Methods: The study was designed as a multi-site case-control study. Cases were patients who had positive PCR for H1N1 influenza and were admitted to the ICU or general ward with a diagnosis of H1N1 influenza from 1 January 2009 to 31 December 2009. Controls were patients who had positive PCR for H1N1 influenza, but were not admitted to hospitals. Results: There were 91 H1N1 cases admitted to either ICU (n?=?41) or general hospital ward (n?=?50), and 56 controls who met the matching criteria were available. Of the 91 cases, the mean age was 47.3 years, 59% were female, and 38% had comorbid conditions. Of the 91 cases, 12 (13%) had asthma. Stratified analysis by comorbid conditions showed that among those without any comorbid conditions, 8 of 56 cases (14%) and 2 of 49 controls (4%) had asthma, (OR: 3.92, 95% CI: 0.79–19.42, p?=?0.095) whereas, among the 39 subjects with one or more comorbid conditions, one of 7 controls (14%) had asthma and 4 of 35 (11%) cases had asthma (p?=?0.83). Conclusions: Asthma may be associated with severity of H1N1 influenza among those without any non-asthma comorbid conditions. However, the limited sample size did not allow this study to fully establish statistical significance. We still recommend asthmatics as a priority group for influenza vaccination and treatment.     

Lack of evidence for pre-symptomatic transmission of pandemic influenza virus A(H1N1) 2009 in an outbreak among teenagers; Germany, 2009

Please cite this paper as: Hermes et al. (2011) Lack of evidence for pre‐symptomatic transmission of pandemic influenza virus A(H1N1) 2009 in an outbreak among teenagers; Germany, 2009. Influenza and Other Respiratory Viruses 5(6), e499–e503. Background Observations on the role of pre‐symptomatic transmission in the spread of influenza virus are scanty. In June 2009, an outbreak of pandemic A(H1N1) 2009 infection occurred at a teenager’s party in Germany. The objective of this study was to identify risk factors for pandemic A(H1N1) 2009 infection. Methods We performed a retrospective cohort study among party guests. A case was defined as pandemic A(H1N1) 2009 infection confirmed by rRT‐PCR who developed influenza‐like illness between 1 and 5 June 2009. Contact patterns among party guests were evaluated. Results In eight (36%) of 27 party guests, the outcome was ascertained. A travel returnee from a country with endemic pandemic A(H1N1) 2009 who fell ill toward the end of the party was identified as the source case. Party guests with pandemic A(H1N1) 2009 infection had talked significantly longer to the source case than non‐infected persons (P‐value: 0·001). Importantly, none (0/9) of those who had left the party prior to the source case’s symptom onset became infected compared to 7 (41%) of 17 who stayed overnight (P = 0·06), and these persons all had transmission‐prone contacts to the source case. Conclusions In this outbreak with one index case, there was no evidence to support pre‐symptomatic transmission of pandemic A(H1N1) 2009. Further evidence is required, ideally from larger studies with multiple index cases, to more accurately characterize the potential for pre‐symptomatic transmission of influenza virus.     

Fatal co-infection with swine origin influenza virus A/H1N1 and community-acquired methicillin-resistant Staphylococcus aureus

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) co-infection has been described previously in association with respiratory tract infection caused by seasonal influenza A viruses, but not with swine origin influenza A (H1N1) virus (S-OIV). We report the clinical and pathological findings of the first death with fulminant co-infection by CA-MRSA. Since early empirical treatment with beta-lactam plus fluoroquinolone or macrolides is often initiated before specimen collections, bacterial co-infection in S-OIV may have been under-reported.     

Detection of 2009 pandemic influenza A(H1N1) virus Infection in different age groups by using rapid influenza diagnostic tests

Please cite this paper as: Gao et al. (2011) Detection of 2009 pandemic influenza A(H1N1) virus Infection in different age groups by using rapid influenza diagnostic tests. Influenza and Other Respiratory Viruses 6(3), e30–e34. Background The performance of rapid influenza diagnostic tests (RIDTs) in detecting influenza A(H1N1) 2009 has varied widely. Evaluations of RIDTs among infected individuals across all age groups have not been described in depth. Objectives Determine RIDT clinical sensitivity in comparison with influenza detection using real‐time RT‐PCR among patients infected with influenza A(H1N1) 2009 across all age groups. Study design This study analyzed respiratory specimens received by the New Hampshire Public Health Laboratories (NHPHL) from September 1, 2009, through December 31, 2009. RIDT performance was evaluated among different age groups of patients determined to be infected with influenza A (H1N1) 2009, and the association between age and RIDT sensitivity was determined. Results Of 1373 specimens examined, 269 tested positive for influenza A(H1N1) 2009 by real‐time RT‐PCR (rRT‐PCR) and had RIDT results available. Overall clinical sensitivity and specificity of RIDTs were 53·9 and 98·5%, respectively. By age group, clinical sensitivity was 85·7% in patients <2 years old, 60·3% in patients between 2‐ and 39 years old, and 33·3% in patients aged 40 and older. Logistic regression analysis indicated that increasing age was negatively associated with RIDT performance. Conclusion Rapid influenza diagnostic test sensitivity decreased significantly with increasing age. Findings from this study may impact a clinician’s interpretation of RIDT test results and ultimately have implications in clinical decision‐making.     

Community-acquired methicillin-resistant Staphylococcus aureus pneumonia: a clinical audit

Background and objective: Community‐associated methicillin‐resistant Staphylococcus aureus (CA‐MRSA) strains are primarily associated with skin and soft tissue infections; however, they are increasingly causing more invasive infections including severe community‐acquired pneumonia. The objective of this study was to describe the clinico‐pathological characteristics of community‐acquired MRSA pneumonia. Methods: A retrospective analysis of case records from January 2002 to August 2008 was performed on patients admitted with community‐acquired MRSA pneumonia to two large teaching hospitals. Results: Sixteen patients with community‐acquired MRSA pneumonia were identified. Their age ranged from 11 months to 86 years (median age; 30 years). Duration of symptoms before hospital presentation ranged from one to 21 days. Most patients had productive cough, fever and dyspnoea. The most common radiological presentation included multilobar consolidation (8/16), necrotizing consolidation (7/16) and empyema (5/16). Seven patients required intensive care support; four required ionotropic support and five required mechanical ventilation for a mean duration of 53 h and 6.6 days, respectively. Six patients underwent surgery (VATS or open thoracotomy). There was a mean delay of approximately 69 h (range; 18 h to 11 days) after presentation before appropriate MRSA antimicrobial treatment was initiated. Three patients died of complications from pneumonia, all within 72 h of presentation. Among survivors, the average length of hospital stay was 23.8 days (range; 10–49 days). Majority of survivors were left with mild residual radiological changes. Conclusions: Community‐acquired MRSA pneumonia is increasing and should be suspected in patients with severe community‐acquired pneumonia. There was a delay in initiation of appropriate antimicrobial treatment that could have lead to increased morbidity.     

Epidemiological and clinical features of respiratory viral infections in hospitalized children during the circulation of influenza virus A(H1N1) 2009

Please cite this paper as: Zuccotti et al. (2011) Epidemiological and clinical features of respiratory viral infections in hospitalized children during the circulation of influenza virus A(H1N1) 2009. Influenza and Other Respiratory Viruses 5(6), e528–e534. Background Seasonal influenza viruses and respiratory syncytial virus (RSV) are primary causes of acute respiratory tract infections (ARTIs) in children. New respiratory viruses including human metapneumovirus (hMPV), human bocavirus (hBoV), and influenza 2009 A(H1N1) virus have a strong impact on the pediatric population. Objectives To evaluate epidemiological and clinical features of ARTIs in hospitalized children. Methods From December 1, 2008, to December 31, 2009, all children under age fifteen (n = 575) hospitalized for ARTIs were investigated for influenza A (subtype H1N1, H3N2, and 2009 H1N1) and B, RSV A and B, hMPV, and hBoV by PCR. Results Fifty‐one percent of samples were positive for these respiratory viruses. The frequencies of virus detection were RSV 34·1%, hBoV 6·8%, hMPV 5%, seasonal influenza A 5%, and seasonal influenza B 0%. From April 2009, 11·6% of collected samples were influenza 2009 A(H1N1) positive. Respiratory syncytial virus activity peaked in January, hBoV in February, and hMPV in April. Seasonal influenza A was detected only between January and April 2009, while influenza 2009 A(H1N1) peaked in November. Respiratory syncytial virus and hMPV were mainly associated with lower respiratory tract infections (LRTIs) and with necessity of O₂ administration. The 2009 pandemic influenza was more frequently detected in elder children (P < 0·001) and was associated with higher, longer‐lasting fevers compared with other viral infections (P < 0·05). Conclusions All considered viruses were involved in LRTIs. The primary clinical relevance of RSV and a similar involvement of both seasonal influenza and emerging viruses investigated were observed on the pediatric population.