Child ; Community-Acquired Infections ; microbiology ; Humans ; Pneumonia, Bacterial ; microbiology

Pneumocystis, an important opportunistic fungal pathogen that parasitizes in multiple mammalian lungs, may cause life-threatening Pneumocystis pneumonia (PCP) and even death among immunocompromised individuals. With the rapid development of high-throughput sequencing and multi-omics technologies, systematic comparative analyses of genome, transcriptome, and whole-genome sequencing results demonstrate that Pneumocystis is a type of obligate biotrophic fungi, and requires obtaining nutrition from hosts. In addition, sexual reproduction is an essential process for Pneumocystis survival, production and transmission, and asexual reproduction facilitates Pneumocystis survival, which provides new insights into understanding of the whole developmental process of Pneumocystis in the host lung and inter-host transmission of Pneumocystis. This review summarizes the advances in the reproduction mode of Pneumocystis and underlying mechanisms, which provides insights into prevention and treatment of PCP, notably for the prophylaxis against nosocomial transmission of PCP.
Humans ; Lung/microbiology* ; Pneumocystis/genetics* ; Pneumonia, Pneumocystis/microbiology*

Bronchoalveolar Lavage ; Child ; Humans ; Pneumonia ; diagnosis ; microbiology

Humans ; Mycoplasma pneumoniae ; pathogenicity ; Pneumonia, Mycoplasma ; microbiology

Humans ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma ; microbiology

Humans ; Papua New Guinea/epidemiology ; Pneumonia/*epidemiology/microbiology/prevention & control

OBJECTIVE: To investigate the characteristics of gut microbiota dysbosis in patients with severe pneumonia using 16SrDNA sequencing. METHODS: A prospective observational research was conducted. The stool samples retained by natural defecation or enema within 2 days after hospital were collected from 16 patients with severe pneumonia admitted to department of intensive care unit (ICU) of General Hospital of Ningxia Medical University from June to December in 2018 and 10 persons for physical exam were enrolled as the healthy control group. The 16SrDNA sequencing technology was used to detect fecal flora and analyze biological information. RESULTS: (1) 1 015 475 effective sequences were obtained from the stool samples from the severe pneumonia group and the healthy control group. Using 16SrDNA method, it was found that the average effective length of the sample sequence was 458.35 bp and the average sequence number of the total samples was 39 056.73. (2) Analysis of α diversity of gut microbiota showed that, compared with the healthy control group, the Ace index, Chao index and the Shannon index of gut microbiota diversity in the severe pneumonia group were significantly decreased [Ace index: 167.23 (143.14, 211.26) vs. 227.71 (214.53, 247.05), Chao index: 152.38 (138.09, 182.54) vs. 228.25 (215.49, 248.95), Shannon index: 2.37 (1.68, 2.89) vs. 3.39 (3.03, 3.63), all P < 0.01], and the Simpson index was significantly increased [0.21 (0.11, 0.33) vs. 0.07 (0.06, 0.12), P < 0.01], which indicated the gut microbiota diversity of the severe pneumonia group was decreased. (3) Analysis of β diversity of gut microbiota, principal coordinate analysis (PCoA) showed that gut microbiota structural with the healthy control group was similar, while that in the severe pneumonia group was different. Adonis analysis showed that the structural of the gut microflora revealing significant differences between the severe pneumonia group and the healthy control group (R² = 0.061, P = 0.05). (4) Analysis of phylum difference gut microflora showed that, compared with the healthy control group, the proportion of Firmicutes in severe pneumonia group was decreased [27.36 (18.12, 39.28)% vs. 52.25 (38.36, 63.82)%, P = 0.02], the proportions of Actinobacterias, Synergistetes and Fusobacterias were increased [2.30 (0.30, 4.80)% vs. 0.02 (0.00, 0.06)%, 0.36 (< 0.01, 0.57)% vs. < 0.01 (< 0.01, < 0.01)%, 0.01 (< 0.01, 0.08)% vs. < 0.01 (< 0.01, < 0.01)%, all P < 0.05]. (5) Analysis of genus difference gut microflora showed that, the proportions of Bifidobacterium, Ruminococcus, Pseudobutyrivibrio, Coprococcus, Lachnospira and Prevotella in the severe pneumonia group were significantly lower than those in healthy control group [0.18 (0.01, 0.25)% vs. 3.40 (0.46, 5.78)%, 0.01 (< 0.01, 0.29)% vs. 2.26 (0.84, 4.86)%, 0.01 (< 0.01, 0.02)% vs. 2.73 (1.87, 5.74)%, 0.02 (< 0.01, 0.07)% vs. 0.80 (0.50, 2.32)%, < 0.01 (< 0.01, < 0.01)% vs. 0.88 (0.33, 2.08)%, 0.02 (< 0.01, 0.31)% vs. 7.74 (0.07, 36.27)%, all P < 0.05]; the proportions of Escherichia and Enterococcus in the severe pneumonia group were higher than those in healthy control group, but there was no difference between the two groups [2.00 (0.57, 10.23)% vs. 1.16 (0.23, 2.68)%, 0.02 (< 0.01, 0.42)% vs. < 0.01 (< 0.01, 0.04)%, both P > 0.05]; the proportions of Fusobacterium and Staphylococcus in severe pneumonia group were significantly higher than those in healthy control group [0.01 (< 0.01, 0.08)% vs. < 0.01 (< 0.01, < 0.01)%, 0.01 (< 0.01, 0.02)% vs. < 0.01 (< 0.01, < 0.01)%, both P < 0.05]. CONCLUSIONS Gut microbiota dysbiosis in patients with severe pneumonia shows that the abundance and diversity decrease, structure of intestinal flora changes, and beneficial symbiotic bacteria decrease and pathogenic bacteria increase, which may be associated with the occurrence and development of severe pneumonia.
Dysbiosis ; Feces ; Gastrointestinal Microbiome ; Humans ; Pneumonia/microbiology* ; Prospective Studies

Bacteria ; isolation & purification ; Community-Acquired Infections ; etiology ; microbiology ; virology ; Humans ; Pneumonia ; etiology ; microbiology ; virology

Adult ; Drug Resistance, Microbial ; Female ; Humans ; Male ; Middle Aged ; Pneumonia ; complications ; microbiology ; Silicotuberculosis ; complications ; microbiology

OBJECTIVETo investigate the spectrum of pathogens for community-acquired pneumonia (CAP) in children, and to provide a basis for the diagnosis and treatment of CAP.

METHODSRespiratory secretions and venous blood samples were collected from 1560 children with CAP aged from one month to 9 years within 2 hours after admission, for detection of multiple pathogens. Respiratory virus antigens in nasopharyngeal swab specimens were detected by immunofluorescence. Sputum was used for bacterial culture. Levels of Mycoplasma pneumoniae (MP)-IgM and Chlamydia pneumoniae (CP)-IgM in venous blood were measured by enzyme-linked immunosorbent assay.

RESULTSA total of 579 strains of bacteria were isolated from all respiratory secretions, including 213 (36.8%) Gram-positive strains and 366 (63.2%) Gram-negative strains. The five most common strains were Haemophilus influenzae (7.50%), Streptococcus pneumoniae (6.73%), Staphylococcus aureus (6.35%), Moraxella catarrhalis (5.19%), and Escherichia coli (3.46%), wherein the beta-lactamase-producing strains accounted for 3.3% of all strains. The non-bacterial pathogens mainly included respiratory syncytial virus (12.88%), MP (7.88%), and CP (8.91%). Mixed infection of pathogens was serious, and the mixed infection of respiratory syncytial virus with Haemophilus influenzae infections were the most common. For most pathogens, the infection rate was higher in children aged under one year than in those aged over one year.

CONCLUSIONSHaemophilus influenzae, respiratory syncytial virus, MP and CP are the main pathogens for children with CAP. For most pathogens, the infection rate is higher in children aged under one year than in those aged over one year. Mixed infection rate of pathogens is high.

Child ; Child, Preschool ; Coinfection ; etiology ; microbiology ; Community-Acquired Infections ; etiology ; microbiology ; Female ; Humans ; Infant ; Male ; Pneumonia ; etiology ; microbiology