Current alternative therapies for treating drug-resistant Neisseria gonorrhoeae causing ophthalmia neonatorum

Ophthalmia neonatorum is a microbial contraction, damaging eyesight, occurring largely among neonates. Infants are particularly vulnerable to bacterial infections acquired during birth from infected mothers, especially from Neisseria gonorrhoeae and Chlamydia trachomatis. Over the decades, N. gonorrhoeae is alarmingly developing a resistance to most antibiotics currently prescribed. To counter this challenge, it is imperative to find potent and cost-effective therapeutic agents for prophylaxis and treatment, to which the N. gonorrhoeae cannot easily develop resistance. This review showcases alternate therapies such as antimicrobial-fatty acids, -peptides, -nano-formulations etc., currently evident against N. gonorrhoeae-mediated ophthalmia neonatorum, which remains a major cause of ocular morbidity, blindness and even death among neonates in developing countries.

Novel Vaccine Strategies and Factors to Consider in Addressing Health Disparities of HPV Infection and Cervical Cancer Development among Native American Women

Cervical cancer is the 4th most common type of cancer in women world-wide. Many factors play a role in cervical cancer development/progression that include genetics, social behaviors, social determinants of health, and even the microbiome. The prevalence of HPV infections and cervical cancer is high and often understudied among Native American communities. While effective HPV vaccines exist, less than 60% of 13- to 17-year-olds in the general population are up to date on their HPV vaccination as of 2020. Vaccination rates are higher among Native American adolescents, approximately 85% for females and 60% for males in the same age group. Unfortunately, the burden of cervical cancer remains high in many Native American populations. In this paper, we will discuss HPV infection, vaccination and the cervicovaginal microbiome with a Native American perspective. We will also provide insight into new strategies for developing novel methods and therapeutics to prevent HPV infections and limit HPV persistence and progression to cervical cancer in all populations.

Novel Selective Inhibition of Lactobacillus iners by Lactobacillus-Derived Bacteriocins

Lactobacillus iners is often associated with vaginal dysbiosis and bacterial vaginosis (BV), which are risk factors for adverse gynecological and obstetric outcomes. To discover natural inhibitors of L. iners, cell-free culture supernatants (CFSs) from 77 vaginal human Lactobacillus strains and 1 human intestinal strain were screened for inhibitory activity. Three active strains were identified, and Lactobacillus paragasseri K7 (K7), a human intestinal strain, produced the most potent L. iners-inhibitory activity. The active material was purified from the K7 CFS and yielded three active peptides, identified as components of two different class IIb, two-peptide bacteriocins, gassericin K7A (GasK7A) and gassericin K7B (GasK7B). The peptides corresponded to the GasK7A α peptide and the GasK7B α and β peptides. While all three peptides exhibited individual activity against L. iners, GasK7B α was the most potent, with an MIC of 23 ng/ml (4 nM). When combined in equal amounts, the GasK7B α and β peptides showed synergistic inhibition, with an MIC of 2 ng/ml (each peptide at 0.4 nM). Among the four major vaginal Lactobacillus species, the K7 bacteriocins selectively inhibited L. iners All 21 strains of L. iners tested (100%) were inhibited by the K7 bacteriocins, whereas <20% of the vaginal Lactobacillus crispatus, L. jensenii, and L. gasseri strains were inhibited. The combination of the BV treatment metronidazole and K7 bacteriocins completely killed both L. iners and Gardnerella vaginalis in a coculture experiment to mimic BV conditions. In contrast, this treatment did not inhibit L. crispatus cultures.IMPORTANCELactobacillus iners is a prevalent species of the vaginal microbiome, but unlike other major vaginal Lactobacillus species, it is not considered protective against BV and can coexist with BV-associated bacteria. L. iners is generally the first Lactobacillus species to emerge following the treatment of BV with metronidazole, and mounting evidence suggests that it may contribute to the onset and maintenance of vaginal dysbiosis. The discovery of highly potent bacteriocins that selectively kill L. iners while sparing protective vaginal lactobacilli may provide novel pharmacological tools to better understand the roles of this enigmatic bacterium in vaginal ecology and potentially lead to new and improved therapies for dysbiosis-related conditions such as BV.

The vaginal microbiota, host defence and reproductive physiology

The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture-independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive-aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic-acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non-Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine-tuned interaction is key to maintaining women's reproductive health.

Antimicrobial peptides in the female reproductive tract: a critical component of the mucosal immune barrier with physiological and clinical implications

BACKGROUND

At the interface of the external environment and the mucosal surface of the female reproductive tract (FRT) lies a first-line defense against pathogen invasion that includes antimicrobial peptides (AMP). Comprised of a unique class of multifunctional, amphipathic molecules, AMP employ a wide range of functions to limit microbial invasion and replication within host cells as well as independently modulate the immune system, dampen inflammation and maintain tissue homeostasis. The role of AMP in barrier defense at the level of the skin and gut has received much attention as of late. Given the far reaching implications for women's health, maternal and fetal morbidity and mortality, and sexually transmissible and polymicrobial diseases, we herein review the distribution and function of key AMP throughout the female reproductive mucosa and assess their role as an essential immunological barrier to microbial invasion throughout the reproductive cycle of a woman's lifetime.

METHODS

A comprehensive search in PubMed/Medline was conducted related to AMP general structure, function, signaling, expression, distribution and barrier function of AMP in the FRT, hormone regulation of AMP, the microbiome of the FRT, and AMP in relation to implantation, pregnancy, fertility, pelvic inflammatory disease, complications of pregnancy and assisted reproductive technology.

RESULTS

AMP are amphipathic peptides that target microbes for destruction and have been conserved throughout all living organisms. In the FRT, several major classes of AMP are expressed constitutively and others are inducible at the mucosal epithelium and by immune cells. AMP expression is also under the influence of sex hormones, varying throughout the menstrual cycle, and dependent on the vaginal microbiome. AMP can prevent infection with sexually transmissible and opportunistic pathogens of the female reproductive tissues, although emerging understanding of vaginal dysbiosis suggests induction of a unique AMP profile with increased susceptibility to these pathogens. During pregnancy, AMP are key immune effectors of the fetal membranes and placenta and are dysregulated in states of intrauterine infection and other complications of pregnancy.

CONCLUSIONS

At the level of the FRT, AMP serve to inhibit infection by sexually and vertically transmissible as well as by opportunistic bacteria, fungi, viruses, and protozoa and must do so throughout the hormone flux of menses and pregnancy. Guarding the exclusive site of reproduction, AMP modulate the vaginal microbiome of the lower FRT to aid in preventing ascending microbes into the upper FRT. Evolving in parallel with, and in response to, pathogenic insults, AMP are relatively immune to the resistance mechanisms employed by rapidly evolving pathogens and play a key role in barrier function and host defense throughout the FRT.