Risk factors and drug resistance in early-onset neonatal group B streptococcal disease

Truncating PICK1 Variant Identified in Azoospermia Affected Mitochondrial Dysfunction in Knockout Mice

OBJECTIVE

The protein interacting with C kinase 1 (PICK1) plays a critical role in vesicle trafficking, and its deficiency in sperm cells results in abnormal vesicle trafficking from Golgi to acrosome, which eventually disrupts acrosome formation and leads to male infertility.

METHODS

An azoospermia sample was filtered, and the laboratory detection and clinical phenotype indicated typical azoospermia in the patient. We sequenced all of the exons in the PICK1 gene and found that there was a novel homozygous variant in the PICK1 gene, c.364delA (p.Lys122SerfsX8), and this protein structure truncating variant seriously affected the biological function. Then we constructed a PICK1 knockout mouse model using clustered regularly interspaced short palindromic repeat cutting technology (CRISPRc).

RESULTS

The sperm from PICK1 knockout mice showed acrosome and nucleus abnormalities, as well as dysfunctional mitochondrial sheath formation. Both the total sperm and motility sperm counts were decreased in the PICK1 knockout mice compared to wild-type mice. Moreover, the mitochondrial dysfunction was verified in the mice. These defects in the male PICK1 knockout mice may have eventually led to complete infertility.

CONCLUSION

The c.364delA novel variant in the PICK1 gene associated with clinical infertility, and pathogenic variants in the PICK1 may cause azoospermia or asthenospermia by impairing mitochondrial function in both mice and humans.

Gut microbiome analysis as a predictive marker for the gastric cancer patients

Gut microbiota have been implicated in the development of cancer. Colorectal and gastric cancers, the major gastrointestinal tract cancers, are closely connected with the gut microbiome. Nevertheless, the characteristics of gut microbiota composition that correlate with gastric cancer are unclear. In this study, we investigated gut microbiota alterations during the progression of gastric cancer to identify the most relevant taxa associated with gastric cancer and evaluated the potential of the microbiome as an indicator for the diagnosis of gastric cancer. Compared with the healthy group, gut microbiota composition and diversity shifted in patients with gastric cancer. Different bacteria were used to design a random forest model, which provided an area under the curve value of 0.91. Verification samples achieved a true positive rate of 0.83 in gastric cancer. Principal component analysis showed that gastritis shares some microbiome characteristics of gastric cancer. Chemotherapy reduced the elevated bacteria levels in gastric cancer by more than half. More importantly, we found that the genera Lactobacillus and Megasphaera were associated with gastric cancer.Key Points• Gut microbiota has high sensitivity and specificity in distinguishing patients with gastric cancer from healthy individuals, indicating that gut microbiota is a potential noninvasive tool for the diagnosis of gastric cancer.• Gastritis shares some microbiota features with gastric cancer, and chemotherapy reduces the microbial abundance and diversity in gastric cancer patients.• Two bacterial taxa, namely, Lactobacillus and Megasphaera, are predictive markers for gastric cancer.

Meningitis vaccines in children: what have we achieved and where next?

PURPOSE OF REVIEW

This review highlights the recent impacts of vaccines against the major bacterial causes of meningitis in children, and the challenges for further prevention of bacterial meningitis, with a focus on Streptococcus pneumoniae, Neisseria meningitidis and group B Streptococcus.

RECENT FINDINGS

Conjugate vaccines against S. pneumoniae and N. meningitidis have resulted in dramatic reductions in bacterial meningitis globally where they have been used. Recent licensure and use of capsular group B meningococcal protein vaccines have further reduced meningococcal meningitis in infants, young children and adolescents for countries with endemic disease and during outbreaks.

SUMMARY

Existing vaccines to prevent bacterial meningitis in children should be utilized in countries with significant numbers of cases of pneumococcal and/or meningococcal meningitis. Vaccines, which are able to protect against more than 13 serotypes of S. pneumoniae are in clinical trials and should be able to further reduce pneumococcal meningitis cases. Cost effective meningococcal vaccines against non-A capsular groups are needed for low-resource countries. There remains an urgent need for a vaccine against group B Streptococcus, which is a major cause of neonatal meningitis globally and for which no vaccine currently exists.