Intestinal carriage of Staphylococcus aureus: How does its frequency compare with that of nasal carriage and what is its clinical impact?

The bacterial species Staphylococcus aureus, including its methicillin-resistant variant (MRSA), finds its primary ecological niche in the human nose, but is also able to colonize the intestines and the perineal region. Intestinal carriage has not been widely investigated despite its potential clinical impact. This review summarizes literature on the topic and sketches the current state of affairs from a microbiological and infectious diseases' perspective. Major findings are that the average reported detection rate of intestinal carriage in healthy individuals and patients is 20% for S. aureus and 9% for MRSA, which is approximately half of that for nasal carriage. Nasal carriage seems to predispose to intestinal carriage, but sole intestinal carriage occurs relatively frequently and is observed in 1 out of 3 intestinal carriers, which provides a rationale to include intestinal screening for surveillance or in outbreak settings. Colonization of the intestinal tract with S. aureus at a young age occurs at a high frequency and may affect the host's immune system. The frequency of intestinal carriage is generally underestimated and may significantly contribute to bacterial dissemination and subsequent risk of infections. Whether intestinal rather than nasal S. aureus carriage is a primary predictor for infections is still ill-defined

Genome-wide association study of 398,238 women unveils seven loci associated with high-grade serous ovarian cancer

Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We meta-analyzed >22 million variants for 398,238 women from the Ovarian Cancer Association Consortium (OCAC), UK Biobank (UKBB) and Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA) to identify novel HGSOC susceptibility loci. Eight novel variants were associated with HGSOC risk. An interesting discovery biologically was TP53 3’-UTR SNP rs78378222-T’s association with HGSOC (per-T-allele relative risk (RR) = 1.44, 95% CI:1.28–1.62, P = 1.76 × 10−9). Polygenic scores (PGS) were developed using OCAC and CIMBA data and trained on FinnGen data. The optimal PGS included 64,518 variants and was associated with an odds ratio of 1.46 (95% CI:1.37–1.54) per standard deviation when validated in the UKBB. This study represents the largest HGSOC GWAS to date – demonstrating that improvements in imputation reference panels and increased sample sizes help to identify HGSOC associated variants that previously went undetected, ultimately improving PGS which can improve personalized HGSOC risk prediction

Methicillin-resistant-Staphylococcus aureus colonization and infection in a rehabilitation facility

Methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in a rehabilitation hospital (Rancho Los Amigos Hospital [RLAH]) were studied from October 1977 to May 1980. Eighty-four episodes of MRSA colonization or infection were observed in 81 patients (attack rate, 0.44 per 100 admissions). The MRSA was considered to have been acquired at RLAH in 65% of the episodes and from transferring hospitals in 34%. The infection rate was 35% among MRSA-colonized patients, and only one death was attributed to MRSA infection. Colonization for more than 100 days occurred most frequently in wounds and anterior nares. All but two of the MRSA isolates were resistant to aminoglycosides, and 80% of those typed belonged to phage type 83A. The patients were allowed to continue participation in rehabilitation programs. Spread of the MRSA occurred in wards where intensive medical and nursing care was being practiced. There was no evidence of MRSA spread in the services with less intense medical and nursing care and where physical and occupational therapy was continued. Patients in a rehabilitation hospital with MRSA colonization may receive intensive physical and occupational therapy as long as special precautions are observed to prevent MRSA spread.</jats:p

Effects of bathing on Pseudomonas and Klebsiella colonization in patients with spinal cord injuries

This study of Pseudomonas aeruginosa and Klebsiella pneumoniae colonization in humans with spinal cord injuries who were using the external urinary collection system showed that meticulous bathing with the bar soap issued by the hospital did not eliminated colonization and was frequently associated with the shifting of these bacteria to adjacent sites on the body. Bacterial counts of the skin showed that bathing did reduce the numbers of P. aeruginosa and K. pneumoniae found on the skin surface and temporarily eliminated these bacteria from some sites. The persistence of these organisms for long periods, even when patients were meticulously bathed, indicates that P. aeruginosa and K. pneumoniae may become part of the resident flora in these patients.</jats:p