A Change in Conservation Status of Pachyphytum caesium (Crassulaceae), a Threatened Species from Central Mexico Based on Genetic Studies.

Genetic studies in rare species are important to determine their patterns of genetic diversity among populations and implement conservation plans aimed to reduce extinction risks. Pachyphytum caesium is an endemic species with extremely small populations in central Mexico. This work analyzes the diversity and genetic structure of Pachyphytum cesium (Crassulaceae) to change the conservation status and propose conservation strategies. Twelve dominant ISSR markers were used to describe the genetic diversity of all known populations. Additionally, we carried out two simulations to explore how the loss of individuals or the local populations extinction affect the genetics parameters of the species. The average results indicated moderate levels of genetic diversity (number of alleles = 89.7 ± 3.9, expected heterozygosity = 0.212 ± 0.0, and percentage of polymorphic loci = 56.1 ± 3.9), parameters that decreased significantly when simulations were performed in P. caesium. Additionally, a genetic structure of the populations was found with low gene flow (Nm = 0.92). Genetic parameters are negatively affected by the loss of individuals and the local extinction of populations. Based on our results, we propose to reclassify the conservation status of the species in danger of extinction, hence a series of conservation strategies are provided to prevent its disappearance.

Drug resistance and phylogenetic grouping of bacteria isolated from visitors' hands in a secondary-care hospital.

INTRODUCTION: Dynamic movement in the hospital environment promotes the transmission of nosocomial pathogens and multidrug resistance mechanisms through the dissemination of organisms that carry genetic determinants. Healthcare workers play an important role in the spread of pathogens; however, the role of visitors in this environment is poorly understood. OBJECTIVE: This study aimed to molecularly identify and examine the antibiotic resistance of the palmar microbiota of patients' companions in a hospital waiting room. METHODOLOGY: Twenty-five palmar surface and interdigital space sample swabs were randomly collected and cultured on blood agar plates, and 19 colonies with different macro- and microscopic characteristics were isolated. The V4 and V6 hypervariable regions of the 16S rRNA gene from each isolate were amplified by PCR and sequenced. Maximum likelihood- and Bayesian inference-based phylogenetic analyses were performed to determine taxonomic relationships. Antibiotic resistance was evaluated by disk diffusion and broth microdilution. RESULTS: Among the isolates, 52.6% were related to Bacillus, 36.8% to Staphylococcus, 5.3% to Enterococcus and 5.3% to Atlantibacter. All of the isolates exhibited ampicillin and penicillin resistance, while 94.7% also exhibited dicloxacillin resistance. Staphylococcus aureus was resistant to penicillins but sensitive to the remaining drugs. Bacteria identified as Bacillus subtilis (MLM14B99), Bacillus pumilus (MLM23B07 and MLM25B06), Staphylococcus epidermidis (MLM24S31 and MLM29S04), and Enterococcus (MLM22E08) showed resistance to at least 46.7% of the antibiotics. CONCLUSIONS: To decrease the transmission of pathogenic bacteria with an antibiotic resistance profile, re-evaluation of hand cleaning measures and their application by people who visit hospital centres is needed.

Determination of drug-resistant bacteria in palmar surface and touchscreen cell phones from bystanders in an urban community.

The dynamic microbiota of the human palmar surface (PS) is related to the various hygienic habits of humans and can be transmitted or exchanged upon contact with objects of daily use, such as the indispensable touchscreen cell phone (TCP); this interaction could allow the development of drug-resistant bacteria. The objective was to determine the drug-resistant bacterial contamination between PSs and TCPs in an urban community. Among the total bacterial colonies isolated and molecular and phylogenetically characterized based on the V4-V6 regions of the 16S rRNA gene from PSs and TCPs, the genera present in both types of samples were Staphylococcus (53.3 and 43.5 %, respectively), Bacillus (37.8, 37 %), Atlantibacter (2.2, 10.8 %) and Microbacterium (2.2, 4.3 %). The genera present in only one type of sample were Rothia, Paenibacillus, Escherichia and Micrococcus (2.2 % each). Resistance to penicillins (35.6-93.5 %) and nonsusceptibility to cephalosporins (8.9-37 %) and nitrofurantoin (13.3 and 15.2 %) were observed. The percentage of multidrug antibiotic resistance was 15.4 %. The prevalence of drug-resistant and multidrug-resistant bacteria in PSs and TCPs in the community could give rise to human health problems, and hygiene measures are recommended.

Evaluation of nest management phases for Lepidochelys olivacea at two beaches in Northwest Mexico.

The olive ridley turtle, Lepidochelys olivacea, is a vulnerable and endangered species according to the IUCN and Mexican Official Standard NOM-059, respectively. On most solitary nesting beaches of olive ridley turtles, the eggs are removed from the in situ nest to hatcheries due to the high incidence of predation, human poaching, and beach erosion; therefore, it is necessary to collect and analyze information on the protection activities conducted for this species from egg laying to hatchling release. In general, protection activities during nest management can be divided into 5 phases: nest logging (F1), egg collection (F2), egg transfer (F3), egg incubation and hatching (F4), and hatchling release (F5). This work was carried out on two Pacific beaches in northwestern Mexico, Ceuta Beach Sanctuary (CBS) during 2013-2019 and Caimanero Beach (CB) during the 2013-2018 nesting seasons, with the objective of quantitatively evaluating the management phases of the protection program for olive ridley turtles by assessing the nest, egg, and hatchling losses in each of the phases using the model of Godínez-Domínguez et al. (1991). The results of the statistical analyses indicate that the greatest losses occurred during the incubation phase (F4) at both beaches, with a 41.99% loss at CBS and a 33.09% loss at CB, followed by the F2 (with 15.56 and 27.27% losses, respectively) and F1 (21.28 and 25.56% losses, respectively) phases. Significant differences between the beaches were observed in F4, F5 and F3, with greater losses at CBS than at CB, indicating that the success of the management phases may vary among beaches. The results obtained show that it is necessary to focus on strategies for improving the success of mainly phase F4 and phases F1 and F2 at both beaches.

Isolation of Gram-Positive, Antibiotic-Resistant Bacteria from Tactile Mobile Phones in a Northwestern Mexican City.

The widespread use of touch-screen mobile devices renders them potential fomites for the transmission of bacterial pathogens among users of different ages. The objectives of the present research were to isolate bacteria from mobile phones, perform molecular and phylogenetic identification, and determine the antibiotic resistance profiles. The surfaces of 50 touch-screen mobile devices owned by bystanders were sampled in the city center of Culiacan, Sinaloa, Mexico. The samples were cultured on nutritive agar; 13 bacterial colonies were isolated and characterized based on their macroscopic and microscopic characteristics and then identified using PCR amplification and sequencing of the 16S rRNA gene V4 and V6 regions. Their taxonomic relationships were determined via a Bayesian inference approach. Antimicrobial resistance was evaluated via disc diffusion and broth microdilution assays. Species of the genera Staphylococcus, Bacillus, and Enterococcus were identified on 84.6, 7.7, and 7.7% of the mobile phones, respectively. A unique subgroup of Staphylococcus epidermidis was identified in strains FBOPL-23, CAEPL-28, and FREPL-28. Staphylococcus hominis novobiosepticus was also identified on mobile phones for the first time. Of the isolated bacteria, 92.3% were resistant to erythromycin, 76.9% to ampicillin and penicillin, 61.5% to dicloxacillin, 38.5% to cephalothin and 7.7% to cefotaxime and ceftriaxone. The presence of antibiotic-resistant bacteria of clinical relevance poses potential risks to users' health and the dissemination of antibiotic resistance mechanisms throughout the community; thus, we recommend regular cleaning to prevent cross-infection by multidrug-resistant bacteria when using touch-screen mobile devices.