Prevalence of precursor lesions (P53 signature, SCOUT, STIL, STIC) in fallopian tubes resected for non-neoplastic causes

BACKGROUND

High-grade pelvic serous carcinoma is a common cause of death in women worldwide and India. Recent evidence has clearly implicated the changes in the mucosa of the fimbrial end of the fallopian tube in its pathogenesis.

OBJECTIVE

1) To study histopathology features of surgically resected specimens of fallopian tubes received with non-neoplastic lesions of the uterus and ovary for the presence of any precursor lesions [secretory cell outgrowth (SCOUT), serous tubal intraepithelial lesion (STIL), p53 signatures, and serous tubal intraepithelial carcinoma (STIC)]. 2) To confirm the findings with immunohistochemistry. 3) To correlate the prevalence of precursor lesions with clinical parameters and benign lesions of the uterus and ovaries.

MATERIALS AND METHODS

Assessment of histopathological changes in 100 specimens of distal fallopian tubes was done using the sectioning and extensive examination of the fimbrial end (SEE-FIM) protocol. H and E stain followed by immunohistochemistry for Bcl-2, p53, and Ki-67. The statistical significance of the difference in the mean values of precursor areas was evaluated by an unpaired t-test.

RESULTS

Among 100 specimens taken on H and E, precursor lesions were suspected in 49% of the cases. SCOUT, suspicious for STIC, suspicious for STIC with areas of SCOUT, and unequivocal for STIC with areas of SCOUT were seen in 8%, 4%, 33%, and 4% of the cases, respectively. However, on IHC, SCOUTS were confirmed in 45% of the cases, p53 signature in 2%, STIL in 9%, and STIC in 4% of the cases.

CONCLUSION

Sectioning and extensive examination of the fimbrial end (SEE-FIM) should be routinely done as it provides the opportunity to detect the early malignant changes. It may help in evolving the strategies for early detection, management, and reducing mortality.

Plasmids shape the diverse accessory resistomes of Escherichia coli ST131

The human gut microbiome includes beneficial, commensal and pathogenic bacteria that possess antimicrobial resistance (AMR) genes and exchange these predominantly through conjugative plasmids. Escherichia coli is a significant component of the gastrointestinal microbiome and is typically non-pathogenic in this niche. In contrast, extra-intestinal pathogenic E. coli (ExPEC) including ST131 may occupy other environments like the urinary tract or bloodstream where they express genes enabling AMR and host cell adhesion like type 1 fimbriae. The extent to which commensal E. coli and uropathogenic ExPEC ST131 share AMR genes remains understudied at a genomic level, and we examined this here using a preterm infant resistome. We found that individual ST131 had small differences in AMR gene content relative to a larger shared resistome. Comparisons with a range of plasmids common in ST131 showed that AMR gene composition was driven by conjugation, recombination and mobile genetic elements. Plasmid pEK499 had extended regions in most ST131 Clade C isolates, and it had evidence of a co-evolutionary signal based on protein-level interactions with chromosomal gene products, as did pEK204 that had a type IV fimbrial pil operon. ST131 possessed extensive diversity of selective type 1, type IV, P and F17-like fimbriae genes that was highest in subclade C2. The structure and composition of AMR genes, plasmids and fimbriae vary widely in ST131 Clade C and this may mediate pathogenicity and infection outcomes.

Vaccines for preventing enterotoxigenic Escherichia coli infections in farm animals

Fimbrial vaccines are routinely given parenterally to pregnant cattle, sheep and swine to protect suckling newborn calves, lambs and pigs against enterotoxigenic Escherichia coli (ETEC) infections. Such vaccines are practical and effective because (1) most fatal ETEC infections in farm animals occur in the early neonatal period when the antibody titres in colostrum and milk are highest; (2) more than 90% of the ETEC in farm animals belong to a small family of fimbrial antigen types; (3) fimbriae consist of good protein antigens on the bacterial surface where they are readily accessible to antibody; (4) fimbriae are required for a critical step (adhesion-colonization) early in the pathogenesis of the disease. ETEC infections continue to be a significant clinical problem in farm animals in spite of extensive use of fimbriae-based vaccines. Definitive data on the efficacy of the commercial vaccines in field use are not available. The prevailing perception among animal health professionals is that the vaccines are effective, that the problem occurs chiefly among non-vaccinated animals, and that in some herds vaccination moves peak prevalence of disease from the first to the second or third week after birth, when mortality is lower. It has been suggested that extensive use of vaccines will rapidly select for the emergence of novel or previously low prevalence fimbrial antigen types. There is no evidence that this has happened after a decade of routine vaccine use in the United States. However, there is no active direct surveillance for such emergence.(ABSTRACT TRUNCATED AT 250 WORDS)