The CRISPR-Cas system in clinical strains of Acinetobacter baumannii: an in-silico analysis.

Acinetobacter baumannii is a relevant bacterium due to its high-resistance profile. It is well known that antimicrobial resistance is primarily linked to mutations and the acquisition of external genomic material, such as plasmids or phages, to which the Clustered Regularly Interspaced Short Palindromic Repeats associated with Cas proteins, or CRISPR-Cas, system is related. It is known that the system can influence the acquisition of foreign genetic material and play a role in various physiological pathways. In this study, we conducted an in-silico analysis using 91 fully assembled genomes of clinical strains obtained from the NCBI database. Among the analyzed genomes, the I-F1 subtype of the CRISPR-Cas system was detected showcasing variations in architecture and phylogeny. Using bioinformatic tools, we determined the presence, distribution, and specific characteristics of the CRISPR-Cas system. We found a possible association of the system with resistance genes but not with virulence determinants. Analysis of the system's components, including spacer sequences, suggests its potential role in protecting against phage infections, highlighting its protective function.

Analysis of Rocky Mountain spotted fever cases in Northern Mexico reveals genetic variability of Rickettsia rickettsii and the different distribution of genotypes.

Rickettsioses have been reported in parts of Mexico since the last century, with Rocky Mountain spotted fever (RMSF) being one of the most prevalent in northern states. Unfortunately, fatality rates for RMSF in Mexico are higher than in other countries, like the USA. The reason for this difference in fatality rates is currently unknown and could be associated with a genotype of the bacterium, but no comparative molecular typing has been conducted in Mexico to date. The purpose of this study was to analyze 47 RMSF samples with different outcomes from several states in northern Mexico to know the genetic variability of Rickettsia rickettsii, as well as to reconstruct its phylogeny, for which the following intergenic regions were sequenced: RR0155-rpmB, cspA-ksgA, RR1240-tlc5, and Spo0J-abc T1, as well as the following partial genes: ompA, ompB, and gltA. We identified 8 genotypes with different distribution and prevalence among the states analyzed, as well as a different association with case outcome; these genotypes were clustered in 2 clades and 5 lineages were revealed, some of them probably exclusive from Mexico.

ESKAPE and Beyond: The Burden of Coinfections in the COVID-19 Pandemic.

The ESKAPE group constitute a threat to public health, since these microorganisms are associated with severe infections in hospitals and have a direct relationship with high mortality rates. The presence of these bacteria in hospitals had a direct impact on the incidence of healthcare-associated coinfections in the SARS-CoV-2 pandemic. In recent years, these pathogens have shown resistance to multiple antibiotic families. The presence of high-risk clones within this group of bacteria contributes to the spread of resistance mechanisms worldwide. In the pandemic, these pathogens were implicated in coinfections in severely ill COVID-19 patients. The aim of this review is to describe the main microorganisms of the ESKAPE group involved in coinfections in COVID-19 patients, addressing mainly antimicrobial resistance mechanisms, epidemiology, and high-risk clones.

Evasion of Antimicrobial Activity in Acinetobacter baumannii by Target Site Modifications: An Effective Resistance Mechanism.

Acinetobacter baumannii is a Gram-negative bacillus that causes multiple infections that can become severe, mainly in hospitalized patients. Its high ability to persist on abiotic surfaces and to resist stressors, together with its high genomic plasticity, make it a remarkable pathogen. Currently, the isolation of strains with high antimicrobial resistance profiles has gained relevance, which complicates patient treatment and prognosis. This resistance capacity is generated by various mechanisms, including the modification of the target site where antimicrobial action is directed. This mechanism is mainly generated by genetic mutations and contributes to resistance against a wide variety of antimicrobials, such as ß-lactams, macrolides, fluoroquinolones, aminoglycosides, among others, including polymyxin resistance, which includes colistin, a rescue antimicrobial used in the treatment of multidrug-resistant strains of A. baumannii and other Gram-negative bacteria. Therefore, the aim of this review is to provide a detailed and up-to-date description of antimicrobial resistance mediated by the target site modification in A. baumannii, as well as to detail the therapeutic options available to fight infections caused by this bacterium.

Colistin Resistance in Aeromonas spp.

The increase in the use of antimicrobials such as colistin for the treatment of infectious diseases has led to the appearance of Aeromonas strains resistant to this drug. However, resistance to colistin not only occurs in the clinical area but has also been determined in Aeromonas isolates from the environment or animals, which has been determined by the detection of mcr genes that confer a resistance mechanism to colistin. The variants mcr-1, mcr-3, and mcr-5 have been detected in the genus Aeromonas in animal, environmental, and human fluids samples. In this article, an overview of the resistance to colistin in Aeromonas is shown, as well as the generalities of this molecule and the recommended methods to determine colistin resistance to be used in some of the genus Aeromonas.

The Challenge of CRISPR-Cas Toward Bioethics.

Since determining the structure of the DNA double helix, the study of genes and genomes has revolutionized contemporary science; with the decoding of the human genome, new findings have been achieved, including the ability that humans have developed to modify genetic sequences in vitro. The discovery of gene modification mechanisms, such as the CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats) and Cas (CRISPR associated). Derived from the latest discoveries in genetics, the idea that science has no limits has exploded. However, improvements in genetic engineering allowed access to new possibilities to save lives or generate new treatment options for diseases that are not treatable by using genes and their modification in the genome. With this greater knowledge, the immediate question is who governs the limits of genetic science? The first answer would be the intervention of a legislative branch, with adequate scientific advice, from which the logical answer, bioethics, should result. This term was introduced for the first time by Van Rensselaer Potter, who in 1970 combined the Greek words bios and ethos, Bio-Ethik, which determined the study of the morality of human behavior in science. The approach to this term was introduced to avoid the natural tension that results from the scientific technical development and the ethics of limits. Therefore, associating the use of biotechnology through the CRISPR-Cas system and the regulation through bioethics, aims to monitor the use of techniques and technology, with benefits for humanity, without altering fundamental rights, acting with moral and ethical principles.

Bacterial Vaginosis and Sexually Transmitted Infections in an HIV-Positive Cohort.

The World Health Organization (WHO) and the Joint United Nations Programme on HIV and AIDS (UNAIDS) suggest that sexually transmitted infection (STI) surveillance should include other genital infections and not only human immunodeficiency virus (HIV). To monitor the concomitance of bacterial vaginosis (BV) and STIs in HIV-seropositive (HIV+) and HIV-seronegative (HIV-) patients, a prospective study was conducted in a cohort of 349 volunteers at a clinic specializing in treating STIs in Mexico City. Microbiological and molecular methods were used to detect STIs and dysbiosis in HIV+ and HIV- individuals. The prevalence of infection was higher in HIV+ (69.28%) than in HIV- (54.87%) individuals. BV was the most frequent infection in HIV+ individuals, and polymicrobial infections were 3 times more common in HIV+ individuals than in HIV- individuals (31.48 vs. 10.98%). Behaviors documented in a self-administered questionnaire included low condom use frequency in HIV+ individuals co-infected with BV or a STI. This finding highlights the importance of surveillance using routine microbiological evaluations for the correct management of genital infections in HIV+ patients because in the presence of HIV, the clinical presentations, courses, and therapeutic responses of some STIs can differ from those in patients without HIV infection.

Patient knowledge of fecal calprotectin in inflammatory bowel disease (IBD): An observational study in Mexico.

Background: Fecal calprotectin (FC) can be a valuable tool to optimize health care for patients with inflammatory bowel disease (IBD). The objective of this observational study was to determine the level of knowledge of the FC test in Mexican patients with IBD. Methods: A self-report questionnaire was distributed via Facebook to patients with IBD. The survey consisted of 15 questions in two categories: the first category assessed knowledge of IBD diagnosis, and the second category assessed knowledge of the FC test. Results: In total, 460 patients with IBD participated, of which 83.9% (386) had ulcerative colitis (UC) and 16.0% (74) had Crohn's disease (CD). Regarding IBD diagnosis, 41.9% of participants stated that they did not know of a non-invasive test for fecal matter to identify inflammation of the colon. Regarding the FC test, 57.5% (UC) and 58.1% (CD) stated that they did not know about the test. Additionally, 65.8% (UC) and 51.3% (CD) of participants stated that they had never received the FC test and 82.6% (UC) and 77.0% (CD) recognized that the FC test was difficult to access in their medical practice. Furthermore, 66% (UC) and 52.7% (CD) of participants noted that their specialist doctor had never suggested the FC test to them, yet 89.1% (UC) and 87.8% (CD) stated that they would prefer FC analysis for their IBD follow-up assessments. Conclusions: There is little knowledge of the FC biomarker among Mexican patients with IBD. This suggests the need for greater dissemination of its use and scope as a biomarker in IBD.

Horizontal Gene Transfer and Its Association with Antibiotic Resistance in the Genus Aeromonas spp.

The evolution of multidrug resistant bacteria to the most diverse antimicrobials known so far pose a serious problem to global public health. Currently, microorganisms that develop resistant phenotypes to multiple drugs are associated with high morbidity and mortality. This resistance is encoded by a group of genes termed 'bacterial resistome', divided in intrinsic and extrinsic resistome. The first one refers to the resistance displayed on an organism without previous exposure to an antibiotic not involving horizontal genetic transfer, and it can be acquired via mutations. The latter, on the contrary, is acquired exclusively via horizontal genetic transfer involving mobile genetic elements that constitute the 'bacterial mobilome'. This transfer is mediated by three different mechanisms: transduction, transformation, and conjugation. Recently, a problem of public health due to implications in the emergence of multi-drug resistance in Aeromonas spp. strains in water environments has been described. This is derived from the genetic material transfer via conjugation events. This is important, since bacteria that have acquired antibiotic resistance in natural environments can cause infections derived from their ingestion or direct contact with open wounds or mucosal tissue, which in turn, by their resistant nature, makes their eradication complex. Implications of the emergence of resistance in Aeromonas spp. by horizontal gene transfer on public health are discussed.

Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City.

Shiga-like toxins (Stx) represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii, and Aeromonas spp.; Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS). The aim of this study was to identify the stx1/stx2 genes in clinical strains and outer membrane vesicles (OMVs) of Aeromonas spp., 66 strains were isolated from children who live in Mexico City, and Stx effects were evaluated in Vero cell cultures. The capacity to express active Stx1 and Stx2 toxins was determined in Vero cell cultures and the concentration of Stx was evaluated by 50% lethal dose (LD50) assays, observing inhibition of damaged cells by specific monoclonal antibodies. The results obtained in this study support the hypothesis that the stx gene is another putative virulence factor of Aeromonas, and since this gene can be transferred horizontally through OMVs this genus should be included as a possible causal agents of gastroenteritis and it should be reported as part of standard health surveillance procedures. Furthermore, these results indicate that the Aeromonas genus might be a potential causative agent of HUS.