Prevalence of respiratory viruses and Mycoplasma pneumoniae in sputum samples from unselected adult patients

The burden of influenza B: a structured literature review

We reviewed the epidemiology, clinical characteristics, disease severity, and economic burden of influenza B as reported in the peer-reviewed published literature. We used MEDLINE to perform a systematic literature review of peer-reviewed, English-language literature published between 1995 and 2010. Widely variable frequency data were reported. Clinical presentation of influenza B was similar to that of influenza A, although we observed conflicting reports. Influenza B-specific data on hospitalization rates, length of stay, and economic outcomes were limited but demonstrated that the burden of influenza B can be significant. The medical literature demonstrates that influenza B can pose a significant burden to the global population. The comprehensiveness and quality of reporting on influenza B, however, could be substantially improved. Few articles described complications. Additional data regarding the incidence, clinical burden, and economic impact of influenza B would augment our understanding of the disease and assist in vaccine development.

Delay in diagnosis of influenza virus in an elderly hospitalized patient: a fatal outcome

Influenza is a well established cause of seasonal hospitalizations and deaths among older persons. However, influenza is frequently underdiagnosed by physicians, because its clinical presentations are often complex, particularly in elderly patients. We report the case of a 78-year-old woman admitted to the emergency department in January 2008 with fever, vomiting, and a history of asthenia and falls in the preceding three days. Diagnosis of influenza at admission was missed. Influenza was diagnosed by direct fluorescent antibody in a sputum specimen four days later, but the evolution was rapidly unfavorable with fatal respiratory distress syndrome. This case illustrates that, during the influenza season, influenza should be suspected in elderly patients admitted to hospital even if they do not present with classical symptoms. Immunofluorescence testing on sputum specimens can provide a rapid diagnosis and merits further evaluation.

[Epidemiology and diagnosis of respiratory syncitial virus in adults]

Introduction

Le virus respiratoire syncytial (VRS) est rarement recherché dans les infections respiratoires de l’adulte. Ce travail en étudie la fréquence et le diagnostic.

Méthodes

Trois enquêtes distinctes ont été menées chez des adultes atteints soit d’un syndrome pseudo-grippal, d’une infection respiratoire basse communautaire ou hospitalisés pour une pneumopathie infectieuse grave. La recherche du VRS a été faite par PCR dans tous les cas et comparée à la détection antigénique et la culture dans deux enquêtes.

Résultats

Le VRS est identifié chez 20 (11,7 %) des 170 adultes vaccinés contre la grippe atteints d’un syndrome pseudo-grippal. Dans 270 infections respiratoires basses communautaires sans signes de gravité on trouve un virus dans 86 (31,8 %) cas, dont 13 VRS (4,8 %) ; un virus est détecté dans 64 (36,7 %) des 164 bronchites aiguës : 11 VRS (6,3 %), 37 rhinovirus (21,3 %), 5 virus influenza A et B, et 12 autres virus ; dans les 60 bronchites chroniques surinfectées, il y a 9 rhinovirus (15 %), 2 virus parainfluenza 3 et aucun VRS ; dans les 21 pneumopathies infectieuses aiguës, on trouve 1 VRS, 1 virus influenza A et 2 rhinovirus, et dans les 11 cas d’infections respiratoires basses sur poumon pathologique, 1 VRS, 1 virus parainfluenza 3 et 4 rhinovirus ; il y a au total 19 infections bactériennes et virales associées. Enfin, dans les 51 pneumopathies infectieuses avec détresse respiratoire hospitalisées en réanimation, un virus est isolé dans 17 (33,3 %) cas : 3 VRS (5,8 %), 6 virus influenza A, 3 rhinovirus, 2 adénovirus, 2 herpes simplex et un CMV ; il y a 6 infections bactériennes associées dont 4 d’origine nosocomiale. Tous les patients infectés par le VRS sont âgés et présentent un facteur de risque respiratoire ou cardiaque.

Conclusions

Chez l’adulte le VRS est responsable de fréquents syndromes pseudo-grippaux et parfois d’infections respiratoires basses, qui peuvent être graves et qu’il faut penser à rechercher. La technique PCR est particulièrement efficace mais non disponible en routine.

Multiple co-infections (Mycoplasma, Chlamydia, human herpes virus-6) in blood of chronic fatigue syndrome patients: association with signs and symptoms

Previously we and others found that a majority of chronic fatigue syndrome (CFS) patients showed evidence of systemic mycoplasmal infections, and their blood tested positive using a polymerase chain reaction assay for at least one of the four following Mycoplasma species: M. fermentans, M. hominis, M. pneumoniae or M. penetrans. Consistent with previous results, patients in the current study (n=200) showed a high prevalence (overall 52%) of mycoplasmal infections. Using forensic polymerase chain reaction we also examined whether these same patients showed evidence of infections with Chlamydia pneumoniae (overall 7.5% positive) and/or active human herpes virus-6 (HHV-6, overall 30.5% positive). Since the presence of one or more infections may predispose patients to other infections, we examined the prevalence of C. pneumoniae and HHV-6 active infections in mycoplasma-positive and -negative patients. Unexpectedly, we found that the incidence of C. pneumoniae or HHV-6 was similar in Mycoplasma-positive and -negative patients, and the converse was also found in active HHV-6-positive and -negative patients. Control subjects (n=100) had low rates of mycoplasmal (6%), active HHV-6 (9%) or chlamydial (1%) infections, and there were no co-infections in control subjects. Differences in bacterial and/or viral infections in CFS patients compared to control subjects were significant. Severity and incidence of patients' signs and symptoms were compared within the above groups. Although there was a tendency for patients with multiple infections to have more severe signs and symptoms (p<0.01), the only significant differences found were in the incidence and severity of certain signs and symptoms in patients with multiple co-infections of any type compared to the other groups (p<0.01). There was no correlation between the type of co-infection and severity of signs and symptoms. The results indicate that a large subset of CFS patients show evidence of bacterial and/or viral infection(s), and these infections may contribute to the severity of signs and symptoms found in these patients.

Comparison of four clinical specimen types for detection of influenza A and B viruses by optical immunoassay (FLU OIA test) and cell culture methods

Although laboratory diagnosis of respiratory viruses has been widely studied, there is a relative insufficiency of literature examining the impact of specimen type on the laboratory diagnosis of influenza A and B. In a clinical study comparing the FLU OIA test with 14-day cell culture, clinical specimens from nasopharyngeal swabs, throat swabs, nasal aspirates, and sputum were obtained from patients experiencing influenza-like symptoms. A total of 404 clinical specimens were collected from 184 patients. Patients were defined as influenza positive if the viral culture of a specimen from any sample site was positive. Patients were defined as influenza negative if the viral cultures of specimens from all sample sites were negative. By this gold standard, culture and FLU OIA test results for each sample type were compared. For each of the four specimen types, the viral culture and FLU OIA test demonstrated equal abilities to detect the presence of influenza A or B virus or viral antigen. Sputum and nasal aspirate samples were the most predictive of influenza virus infection. Throat swabs were the least predictive of influenza virus infection, with both tests failing to detect influenza virus in nearly 50% of the throat samples studied.

Incidence of upper respiratory tract Mycoplasma pneumoniae infections among outpatients in Rhône-Alpes, France, during five successive winter periods

In this prospective study, nasal swab samples from patients with acute respiratory infections were evaluated for the presence of Mycoplasma pneumoniae. This PCR-plus-hybridization-based detection was associated with the detection of other viral agents. During the five winter surveillance periods, 3,897 samples were collected by 75 medical practitioners participating in the Groupe Régional d'Observation de la Grippe surveillance network in Rhône-Alpes (France). M. pneumoniae was detected in 283 samples (7.3%); its rate of detection ranged from 10.1 to 2.0% over the five periods, and it was the second most frequently isolated pathogen during the survey, after influenza A. Three high-prevalence winters were observed, yielding an early winter peak of M. pneumoniae infection which was observed in all age groups. No statistically significant difference was detected between rates of infections in the different age groups, but M. pneumoniae infection was significantly related to lower respiratory tract infection during periods of high prevalence. This study defined the frequency of M. pneumoniae detection from nasal swab specimens in patients with acute respiratory infections, confirming its high prevalence and the presence of large outbreaks due to this pathogen.