Within-host evolution of Staphylococcus aureus during asymptomatic carriage

Background Staphylococcus aureus is a major cause of healthcare associated mortality, but like many important bacterial pathogens, it is a common constituent of the normal human body flora. Around a third of healthy adults are carriers. Recent evidence suggests that evolution of S. aureus during nasal carriage may be associated with progression to invasive disease. However, a more detailed understanding of within-host evolution under natural conditions is required to appreciate the evolutionary and mechanistic reasons why commensal bacteria such as S. aureus cause disease. Therefore we examined in detail the evolutionary dynamics of normal, asymptomatic carriage. Sequencing a total of 131 genomes across 13 singly colonized hosts using the Illumina platform, we investigated diversity, selection, population dynamics and transmission during the short-term evolution of S. aureus. Principal Findings We characterized the processes by which the raw material for evolution is generated: micro-mutation (point mutation and small insertions/deletions), macro-mutation (large insertions/deletions) and the loss or acquisition of mobile elements (plasmids and bacteriophages). Through an analysis of synonymous, non-synonymous and intergenic mutations we discovered a fitness landscape dominated by purifying selection, with rare examples of adaptive change in genes encoding surface-anchored proteins and an enterotoxin. We found evidence for dramatic, hundred-fold fluctuations in the size of the within-host population over time, which we related to the cycle of colonization and clearance. Using a newly-developed population genetics approach to detect recent transmission among hosts, we revealed evidence for recent transmission between some of our subjects, including a husband and wife both carrying populations of methicillin-resistant S. aureus (MRSA). Significance This investigation begins to paint a picture of the within-host evolution of an important bacterial pathogen during its prevailing natural state, asymptomatic carriage. These results also have wider significance as a benchmark for future systematic studies of evolution during invasive S. aureus disease

Variant adrenal venous anatomy in 546 laparoscopic adrenalectomies

Importance: Knowing the types and frequency of adrenal vein variants would help surgeons identify and control the adrenal vein during laparoscopic adrenalectomy. Objectives: To establish the surgical anatomy of the main vein and its variants for laparoscopic adrenalectomy and to analyze the relationship between variant adrenal venous anatomy and tumor size, pathologic diagnosis, and operative outcomes. Design, Setting, and Patients: In a retrospective review of patients at a tertiary referral hospital, 506 patients underwent 546 consecutive laparoscopic adrenalectomies between April 22, 1993, and October 21, 2011. Patients with variant adrenal venous anatomy were compared with patients with normal adrenal venous anatomy regarding preoperative variables (patient and tumor characteristics [size and location] and clinical diagnosis), intraoperative variables (details on the main adrenal venous drainage, any variant venous anatomy, duration of operation, rate of conversion to hand-assisted or open procedure, and estimated blood loss), and postoperative variables (transfusion requirement, reoperation for bleeding, duration of hospital stay, and histologic diagnosis). Intervention: Laparoscopic adrenalectomy. Main Outcomes and Measures: Prevalence of variant adrenal venous anatomy and its relationship to tumor characteristics, pathologic diagnosis, and operative outcomes. Results: Variant venous anatomy was encountered in 70 of 546 adrenalectomies (13%). Variants included no main adrenal vein identifiable (n=18), 1 main adrenal vein with additional small veins (n=11), 2 adrenal veins (n=20), more than 2 adrenal veins (n=14), and variants of the adrenal vein drainage to the inferior vena cava and hepatic vein or of the inferior phrenic vein (n=7). Variants occurred more often on the right side than on the left side (42 of 250 glands [17%] vs 28 of 296 glands [9%], respectively; P=.02). Patients with variant anatomy compared with those with normal anatomy had larger tumors (mean, 5.1 vs 3.3 cm, respectively; P>.001), more pheochromocytomas (24 of 70 [35%] vs 100 of 476 [21%], respectively; P=.02), and more estimated blood loss (mean, 134 vs 67 mL, respectively; P=.01). For patients with variant anatomy vs those with normal anatomy, the rates of transfusion requirement (2 of 70 [3%] vs 10 of 476 [2%], respectively; P=.69) and reoperation for bleeding (1 of 70 [1%] vs 3 of 476 [1%]; P=.46) were similar between groups. Conclusions and Relevance: Understanding variant adrenal venous anatomy is important to avoid bleeding during laparoscopic adrenalectomy, particularly in patients with large tumors or pheochromocytomas. Surgeons should anticipate a higher probability of adrenal vein variants when operating on pheochromocytomas and larger adrenal tumors. © 2013 American Medical Association

Variant adrenal venous anatomy in 546 laparoscopic adrenalectomies

Importance: Knowing the types and frequency of adrenal vein variants would help surgeons identify and control the adrenal vein during laparoscopic adrenalectomy. Objectives: To establish the surgical anatomy of the main vein and its variants for laparoscopic adrenalectomy and to analyze the relationship between variant adrenal venous anatomy and tumor size, pathologic diagnosis, and operative outcomes. Design, Setting, and Patients: In a retrospective review of patients at a tertiary referral hospital, 506 patients underwent 546 consecutive laparoscopic adrenalectomies between April 22, 1993, and October 21, 2011. Patients with variant adrenal venous anatomy were compared with patients with normal adrenal venous anatomy regarding preoperative variables (patient and tumor characteristics [size and location] and clinical diagnosis), intraoperative variables (details on the main adrenal venous drainage, any variant venous anatomy, duration of operation, rate of conversion to hand-assisted or open procedure, and estimated blood loss), and postoperative variables (transfusion requirement, reoperation for bleeding, duration of hospital stay, and histologic diagnosis). Intervention: Laparoscopic adrenalectomy. Main Outcomes and Measures: Prevalence of variant adrenal venous anatomy and its relationship to tumor characteristics, pathologic diagnosis, and operative outcomes. Results: Variant venous anatomy was encountered in 70 of 546 adrenalectomies (13%). Variants included no main adrenal vein identifiable (n=18), 1 main adrenal vein with additional small veins (n=11), 2 adrenal veins (n=20), more than 2 adrenal veins (n=14), and variants of the adrenal vein drainage to the inferior vena cava and hepatic vein or of the inferior phrenic vein (n=7). Variants occurred more often on the right side than on the left side (42 of 250 glands [17%] vs 28 of 296 glands [9%], respectively; P=.02). Patients with variant anatomy compared with those with normal anatomy had larger tumors (mean, 5.1 vs 3.3 cm, respectively; P>.001), more pheochromocytomas (24 of 70 [35%] vs 100 of 476 [21%], respectively; P=.02), and more estimated blood loss (mean, 134 vs 67 mL, respectively; P=.01). For patients with variant anatomy vs those with normal anatomy, the rates of transfusion requirement (2 of 70 [3%] vs 10 of 476 [2%], respectively; P=.69) and reoperation for bleeding (1 of 70 [1%] vs 3 of 476 [1%]; P=.46) were similar between groups. Conclusions and Relevance: Understanding variant adrenal venous anatomy is important to avoid bleeding during laparoscopic adrenalectomy, particularly in patients with large tumors or pheochromocytomas. Surgeons should anticipate a higher probability of adrenal vein variants when operating on pheochromocytomas and larger adrenal tumors. © 2013 American Medical Association

Socioeconomic status significantly contributes to the likelihood of immediate postmastectomy breast reconstruction in the Netherlands: A nationwide study

Background: Previous studies have shown that breast cancer patients with a low socioeconomic status (SES) are less likely to undergo postmastectomy immediate breast reconstruction (IBR). However, these studies were performed in countries with unequal access to healthcare. Therefore, the aim of this study was to investigate whether SES also contributes to the likelihood of receiving IBR in a country with equal access to healthcare. Materials and methods: Patients with stage I or II breast cancer diagnosed between 2011 and 2018 who underwent mastectomy were selected from the Netherlands Cancer Registry. SES was calculated from the average incomes of each postal code which were divided into 10-deciles. Primary outcome was the effect of SES on the likelihood of receiving IBR, controlled for patient, tumour and hospital characteristics expressed as Odds Ratio (OR) with 95% confidence interval (CI). Results: Higher SES significantly increased the probability of undergoing postmastectomy IBR (OR 1.05 per 10% SES stratum), just as larger hospital volume (average volume OR 1.89 and large volume 2.58), oestrogen positive tumours (OR 1.19) and neo-adjuvant therapy (OR 1.42). In contrast, factors significantly reducing the likelihood of receiving IBR were older age (OR 0.92 per year), stage II (OR 0.61 compared to stage I) and adjuvant therapy (OR 0.56). Conclusion: Women with lower SES undergoing mastectomy were less likely to receive postmastectomy IBR. More research is warranted to study whether lifestyle factors associated with lower SES such as smoking and higher BMI, language barrier, illiteracy and less access to internet explain these differences

Colonization with multiple Staphylococcus aureus strains among patients in European intensive care units.

Patients and healthy individuals intermittently and inconsistently carry different methicillin-resistant Staphylococcus aureus (MRSA) subtypes. In the present study, we assessed the clonality of methicillin-susceptible S. aureus (MSSA) and MRSA strains in patients admitted to 1 of 6 intensive care units (ICUs), using spa typing and multilocus variable number of tandem repeats analysis (MLVA).Ye