Prolonged Mycoplasma pneumoniae infection in an elderly patient with community-acquired pneumonia

Exploratory studies of oral and fecal microbiome in healthy human aging

Growing evidence has linked an altered host fecal microbiome composition with health status, common chronic diseases, and institutionalization in vulnerable older adults. However, fewer studies have described microbiome changes in healthy older adults without major confounding diseases or conditions, and the impact of aging on the microbiome across different body sites remains unknown. Using 16S ribosomal RNA gene sequencing, we reconstructed the composition of oral and fecal microbiomes in young (23-32; mean = 25 years old) and older (69-94; mean = 77 years old) healthy community-dwelling research subjects. In both body sites, we identified changes in minor bacterial operational taxonomic units (OTUs) between young and older subjects. However, the composition of the predominant bacterial species of the healthy older group in both microbiomes was not significantly different from that of the young cohort, which suggests that dominant bacterial species are relatively stable with healthy aging. In addition, the relative abundance of potentially pathogenic genera, such as Rothia and Mycoplasma, was enriched in the oral microbiome of the healthy older group relative to the young cohort. We also identified several OTUs with a prevalence above 40% and some were more common in young and others in healthy older adults. Differences with aging varied for oral and fecal samples, which suggests that members of the microbiome may be differentially affected by aging in a tissue-specific fashion. This is the first study to investigate both oral and fecal microbiomes in the context of human aging, and provides new insights into interactions between aging and the microbiome within two different clinically relevant sites.

A Compendium for Mycoplasma pneumoniae

Historically, atypical pneumonia was a term used to describe an unusual presentation of pneumonia. Currently, it is used to describe the multitude of symptoms juxtaposing the classic symptoms found in cases of pneumococcal pneumonia. Specifically, atypical pneumonia is a syndrome resulting from a relatively common group of pathogens including Chlamydophila sp., and Mycoplasma pneumoniae. The incidence of M. pneumoniae pneumonia in adults is less than the burden experienced by children. Transmission rates among families indicate children may act as a reservoir and maintain contagiousness over a long period of time ranging from months to years. In adults, M. pneumoniae typically produces a mild, “walking” pneumonia and is considered to be one of the causes of persistent cough in patients. M. pneumoniae has also been shown to trigger the exacerbation of other lung diseases. It has been repeatedly detected in patients with bronchitis, asthma, chronic obstructive pulmonary disorder, and cystic fibrosis. Recent advances in technology allow for the rapid diagnosis of M. pneumoniae through the use of polymerase chain reaction or rapid antigen tests. With this, more effort has been afforded to identify the causative etiologic agent in all cases of pneumonia. However, previous practices, including the overprescribing of macrolide treatment in China and Japan, have created increased incidence of macrolide-resistant M. pneumoniae. Reports from these countries indicate that >85% of M. pneumoniae pneumonia pediatric cases are macrolide-resistant. Despite its extensively studied past, the smallest bacterial species still inspires some of the largest questions. The developments in microbiology, diagnostic features and techniques, epidemiology, treatment and vaccines, and upper respiratory conditions associated with M. pneumoniae in adult populations are included within this review.

Minocycline as A Substitute for Doxycycline in Targeted Scenarios: A Systematic Review

Doxycycline remains on intermittent shortage. Evidence supports the substitution of minocycline in skin and soft-tissue infections and carefully selected cases of pneumonia. Minocycline may be carefully considered in Lyme disease prophylaxis and Rickettsial disease in the complete absence of doxycycline.

Doxycycline, a commonly prescribed tetracycline, remains on intermittent shortage. We systematically reviewed the literature to assess minocycline as an alternative to doxycycline in select conditions, given doxycycline's continued shortage. We identified 19 studies, 10 of which were published before 2000. Thirteen of the studies were prospective, but only 1 of these studies was randomized. Based on the available data, we found minocycline to be a reasonable substitute for doxycycline in the following scenarios: skin and soft-tissue infections and outpatient treatment of community-acquired pneumonia in young, otherwise healthy patients or in patients with macrolide-resistant Mycoplasma pneumoniae, as well as Lyme disease prophylaxis and select rickettsial disease should doxycycline be unavailable.

Serologic prevalence of amoeba-associated microorganisms in intensive care unit pneumonia patients

BACKGROUND

Patients admitted to intensive care units are frequently exposed to pathogenic microorganisms present in their environment. Exposure to these microbes may lead to the development of hospital-acquired infections that complicate the illness and may be fatal. Amoeba-associated microorganisms (AAMs) are frequently isolated from hospital water networks and are reported to be associated to cases of community and hospital-acquired pneumonia.

METHODOLOGY/PRINCIPAL FINDINGS

We used a multiplexed immunofluorescence assay to test for the presence of antibodies against AAMs in sera of intensive care unit (ICU) pneumonia patients and compared to patients at the admission to the ICU (controls). Our results show that some AAMs may be more frequently detected in patients who had hospital-acquired pneumonia than in controls, whereas other AAMs are ubiquitously detected. However, ICU patients seem to exhibit increasing immune response to AAMs when the ICU stay is prolonged. Moreover, concomitant antibodies responses against seven different microorganisms (5 Rhizobiales, Balneatrix alpica, and Mimivirus) were observed in the serum of patients that had a prolonged ICU stay.

CONCLUSIONS/SIGNIFICANCE

Our work partially confirms the results of previous studies, which show that ICU patients would be exposed to water amoeba-associated microorganisms, and provides information about the magnitude of AAM infection in ICU patients, especially patients that have a prolonged ICU stay. However, the incidence of this exposure on the development of pneumonia remains to assess.

Two cases of Mycoplasma pneumoniae pneumonia with A2063G mutation in the 23S rRNA gene in siblings

We describe 2 cases of pneumonia caused by the same macrolide-resistant Mycoplasma pneumoniae in siblings. M. pneumoniae was identified using real-time PCR. Direct sequence analysis of the 23S rRNA gene revealed a point mutation in V domain (A2063G) of the 23S rRNA gene.

Macrolide-resistant Mycoplasma pneumoniae: characteristics of isolates and clinical aspects of community-acquired pneumonia

Mycoplasma pneumoniae is one of the main pathogens causing community-acquired respiratory tract infections in children and adults. Macrolide (ML) antibiotics are recognized generally as first-choice agents for M. pneumoniae infections, and these antibiotics were thought to have excellent effectiveness against M. pneumoniae for many years. In 2000, however, M. pneumoniae showing resistance to macrolides was isolated from clinical samples obtained from Japanese pediatric patients with community-acquired pneumonia (CAP). Since then, prevalence of ML-resistant M. pneumoniae isolates in pediatric patients has increased rapidly. In 2007, ML-resistant M. pneumoniae isolates were obtained from Japanese adults with CAP; numbers of such isolates also have gradually increased in Japan. Recently, similar antimicrobial resistance in M. pneumoniae has begun to emerge worldwide. In this review, we focus on changes of ML-resistant M. pneumoniae from year to year and consider resistance mechanisms as well as clinical features of patients with resistant M. pneumoniae infection.