Foldy: An open-source web application for interactive protein structure analysis.

Foldy is a cloud-based application that allows non-computational biologists to easily utilize advanced AI-based structural biology tools, including AlphaFold and DiffDock. With many deployment options, it can be employed by individuals, labs, universities, and companies in the cloud without requiring hardware resources, but it can also be configured to utilize locally available computers. Foldy enables scientists to predict the structure of proteins and complexes up to 6000 amino acids with AlphaFold, visualize Pfam annotations, and dock ligands with AutoDock Vina and DiffDock. In our manuscript, we detail Foldy's interface design, deployment strategies, and optimization for various user scenarios. We demonstrate its application through case studies including rational enzyme design and analyzing proteins with domains of unknown function. Furthermore, we compare Foldy's interface and management capabilities with other open and closed source tools in the field, illustrating its practicality in managing complex data and computation tasks. Our manuscript underlines the benefits of Foldy as a day-to-day tool for life science researchers, and shows how Foldy can make modern tools more accessible and efficient.

Development of Corynebacterium glutamicum as a monoterpene production platform.

Monoterpenes are commonly known for their role in the flavors and fragrances industry and are also gaining attention for other uses like insect repellant and as potential renewable fuels for aviation. Corynebacterium glutamicum, a Generally Recognized as Safe microbe, has been a choice organism in industry for the annual million ton-scale bioproduction of amino acids for more than 50 years; however, efforts to produce monoterpenes in C. glutamicum have remained relatively limited. In this study, we report a further expansion of the C. glutamicum biosynthetic repertoire through the development and optimization of a mevalonate-based monoterpene platform. In the course of our plasmid design iterations, we increased flux through the mevalonate-based bypass pathway, measuring isoprenol production as a proxy for monoterpene precursor abundance and demonstrating the highest reported titers in C. glutamicum to date at 1504.6 mg/L. Our designs also evaluated the effects of backbone, promoter, and GPP synthase homolog origin on monoterpene product titers. Monoterpene production was further improved by disrupting competing pathways for isoprenoid precursor supply and by implementing a biphasic production system to prevent volatilization. With this platform, we achieved 321.1 mg/L of geranoids, 723.6 mg/L of 1,8-cineole, and 227.8 mg/L of linalool. Furthermore, we determined that C. glutamicum first oxidizes geraniol through an aldehyde intermediate before it is asymmetrically reduced to citronellol. Additionally, we demonstrate that the aldehyde reductase, AdhC, possesses additional substrate promiscuity for acyclic monoterpene aldehydes.

The AMIGO1 adhesion protein activates Kv2.1 voltage sensors.

Kv2 voltage-gated potassium channels are modulated by amphoterin-induced gene and open reading frame (AMIGO) neuronal adhesion proteins. Here, we identify steps in the conductance activation pathway of Kv2.1 channels that are modulated by AMIGO1 using voltage-clamp recordings and spectroscopy of heterologously expressed Kv2.1 and AMIGO1 in mammalian cell lines. AMIGO1 speeds early voltage-sensor movements and shifts the gating charge-voltage relationship to more negative voltages. The gating charge-voltage relationship indicates that AMIGO1 exerts a larger energetic effect on voltage-sensor movement than is apparent from the midpoint of the conductance-voltage relationship. When voltage sensors are detained at rest by voltage-sensor toxins, AMIGO1 has a greater impact on the conductance-voltage relationship. Fluorescence measurements from voltage-sensor toxins bound to Kv2.1 indicate that with AMIGO1, the voltage sensors enter their earliest resting conformation, yet this conformation is less stable upon voltage stimulation. We conclude that AMIGO1 modulates the Kv2.1 conductance activation pathway by destabilizing the earliest resting state of the voltage sensors.

Controlled (Co)Polymerization of Methacrylates Using a Novel Symmetrical Trithiocarbonate RAFT Agent Bearing Diphenylmethyl Groups.

Herein, we report a novel type of symmetrical trithiocarbonate chain transfer agent (CTA) based diphenylmethyl as R groups. The utilization of this CTA in the Reversible Addition-Fragmentation chain Transfer (RAFT) process reveals an efficient control in the polymerization of methacrylic monomers and the preparation of block copolymers. The latter are obtained by the (co)polymerization of styrene or butyl acrylate using a functionalized macro-CTA polymethyl methacrylate (PMMA) previously synthesized. Data show low molecular weight dispersity values (D < 1.5) particularly in the polymerization of methacrylic monomers. Considering a typical RAFT mechanism, the leaving groups (R) from the fragmentation of CTA should be able to re-initiate the polymerization (formation of growth chains) allowing an efficient control of the process. Nevertheless, in the case of the polymerization of MMA in the presence of this symmetrical CTA, the polymerization process displays an atypical behavior that requires high [initiator]/[CTA] molar ratios for accessing predictable molecular weights without affecting the D. Some evidence suggests that this does not completely behave as a common RAFT agent as it is not completely consumed during the polymerization reaction, and it needs atypical high molar ratios [initiator]/[CTA] to be closer to the predicted molecular weight without affecting the D. This work demonstrates that MMA and other methacrylic monomers can be polymerized in a controlled way, and with "living" characteristics, using certain symmetrical trithiocarbonates.

Chemoinformatic-Guided Engineering of Polyketide Synthases.

Polyketide synthase (PKS) engineering is an attractive method to generate new molecules such as commodity, fine and specialty chemicals. A significant challenge is re-engineering a partially reductive PKS module to produce a saturated ß-carbon through a reductive loop (RL) exchange. In this work, we sought to establish that chemoinformatics, a field traditionally used in drug discovery, offers a viable strategy for RL exchanges. We first introduced a set of donor RLs of diverse genetic origin and chemical substrates  into the first extension module of the lipomycin PKS (LipPKS1). Product titers of these engineered unimodular PKSs correlated with chemical structure similarity between the substrate of the donor RLs and recipient LipPKS1, reaching a titer of 165 mg/L of short-chain fatty acids produced by the host Streptomyces albus J1074. Expanding this method to larger intermediates that require bimodular communication, we introduced RLs of divergent chemosimilarity into LipPKS2 and determined triketide lactone production. Collectively, we observed a statistically significant correlation between atom pair chemosimilarity and production, establishing a new chemoinformatic method that may aid in the engineering of PKSs to produce desired, unnatural products.

A bimodular PKS platform that expands the biological design space.

Traditionally engineered to produce novel bioactive molecules, Type I modular polyketide synthases (PKSs) could be engineered as a new biosynthetic platform for the production of de novo fuels, commodity chemicals, and specialty chemicals. Previously, our investigations manipulated the first module of the lipomycin PKS to produce short chain ketones, 3-hydroxy acids, and saturated, branched carboxylic acids. Building upon this work, we have expanded to multi-modular systems by engineering the first two modules of lipomycin to generate unnatural polyketides as potential biofuels and specialty chemicals in Streptomyces albus. First, we produce 20.6 mg/L of the ethyl ketone, 4,6 dimethylheptanone through a reductive loop exchange in LipPKS1 and a ketoreductase knockouts in LipPKS2. We then show that an AT swap in LipPKS1 and a reductive loop exchange in LipPKS2 can produce the potential fragrance 3-isopropyl-6-methyltetrahydropyranone. Highlighting the challenge of maintaining product fidelity, in both bimodular systems we observed side products from premature hydrolysis in the engineered first module and stalled dehydration in reductive loop exchanges. Collectively, our work expands the biological design space and moves the field closer to the production of "designer" biomolecules.

Improving laccase production from Trametes versicolor using lignocellulosic residues as cosubstrates and evaluation of enzymes for blue wastewater biodegradation.

Biocatalytic degradation of recalcitrant pollutants employing ligninolytic enzymes is a promising approach for wastewater treatment. However, enzymes production must be improved to make biodegradation a more cost-effective treatment. In this research, laccase production from Trametes versicolor using lignocellulosic residues (agave bagasse, coconut fibers and wheat bran) as cosubstrates was improved using a central composite face-centered design, and the application of the enzymes-rich culture supernatant was evaluated for blue wastewater biodegradation. Findings revealed that the optimal conditions for laccase production were found at 35 °C and 5 g/L of wheat bran as cosubstrate, reaching about 200 U/mL in 11 days in a batch submerged fermentation. These conditions were scaled up for a submerged fermentation using an airlift reactor, and a maximum enzymatic activity of 1200 U/mL was achieved in 9 days at 30 °C. This enzymes-rich culture supernatant was tested for the degradation of blue wastewater from aircraft in an airlift reactor. Results showed a COD removal efficiency of 43% and an increase of the biodegradability index from 0.64 to 1.36, both results applying an enzymatic activity of supernatant of 300 U/mL. In conclusion, the enzymatic biodegradation becomes a viable strategy for the pretreatment of a real effluent such as the blue wastewater collected in public transportation.

Impact of the caregiver burden on the effectiveness of a home-based palliative care program: A mediation analysis.

OBJECTIVE: The growing aging population and the high prevalence of several concomitant chronic diseases have contributed to the elevated rates of caregiver burden and suffering in patients. In turn, intending to relieve unnecessary pain in patients, there has been a rapid growth of outpatient palliative care programs. However, little has been studied about caregiver burden as a relevant factor potentially affecting the effectiveness of these programs. This study aimed to determine the extent of caregiver burden as a possible mediator on the effectiveness of a home-based palliative care program. METHOD: Sixty-six palliative patients (56% women; mean age + SD = 71, 6 ± 17.7) and their caregivers were assessed with measures for physical, emotional, and psychological symptoms before and 1 month after the start of a home-based palliative care program. RESULTS: The association between caregiver burden and palliative outcomes was corroborated with a categorical regression model (p < 0.01). Caregiver burden was found to be a significant mediator in the relationship between outcome measures for palliative care at baseline and after 1 month of enrollment in the program. SIGNIFICANCE OF RESULTS: To our knowledge, this is the first study to assess the role of caregiver burden in the effectiveness of a home-based palliative care program. Although further work is required, the results indicate that a patient-focused intervention does not have the same beneficial effect if the caregiver burden is not addressed. Future home-based palliative care programs should focus on caregivers as well as patients, with particular attention to psychosocial intervention on caregivers.

Seven-enzyme in vitro cascade to (3R)-3-hydroxybutyryl-CoA.

Economical and environmentally-friendly routes to convert feedstock chemicals like acetate into valuable chiral products such as (R)-3-hydroxybutyrate are in demand. Here, seven enzymes (CoaA, CoaD, CoaE, ACS, BktB, PhaB, and GDH) are employed in a one-pot, in vitro, biocatalytic synthesis of (3R)-3-hydroxybutyryl-CoA, which was readily isolated. This platform generates not only chiral diketide building blocks but also desirable CoA derivatives.

Buccal Fat Pad Excision: Hydrodissection Technique.

BACKGROUND: Buccal fat pad (BFP) excision is a procedure in which the fat pad is extracted in order to achieve a more youthful appearance. OBJECTIVES: The aim of this study was to describe an alternative technique that utilizes hydrodissection to extract the BFP. METHODS: This is a controlled, prospective, randomized clinical study involving 2 groups. Group A (n = 27) underwent BFP excision with hydrodissection, during which 15 mL of a vasoconstricting anesthetic solution was injected into the BFP. Group B (n = 27) underwent BFP excision, during which 3 mL of lidocaine 2% with epinephrine was injected. All procedures were performed by the same surgeon. Variables analyzed were surgical time, intraoperative bleeding, and postoperative pain directly following surgery 2 hours after the procedure, as well as maximum pain within 72 hours of surgery and complications. Postoperative care was standardized, and patient follow-up extended over a 6-month period. RESULTS: Pain scores for 54 patients were recorded on a visual analog scale (0-10). Mean ± standard deviation transoperative pain scores were 0.5 ± 0.8 for Group A and 1.3 ± 1.3 for Group B (P = 0.01); 2 hours postoperation the scores were 1.2 ± 0.7 for Group A and 2.6 ± 1 for Group B (P < 0.0001). Maximum pain occurred within 72 hours, and scored 1.6 ± 0.6 for Group A and 3.1 ± 1 for Group B (P < 0.0001). Mean operative time was 8:18 ± 0:47 minutes for Group A and 14:08 ± 2:28 minutes for Group B (P < 0.0001). There was a positive correlation between operative time and pain. Overall, 5.5% of patients suffered postoperative complications. CONCLUSIONS: BFP excision by hydrodissection is an effective procedure that decreases surgical times by facilitating extraction of the BFP with less manipulation, thereby resulting in decreased postoperative pain and a more tolerable recovery.

[Supervivencia en cáncer de mama por subtipo mediante inmunohistoquímica: Un estudio retrospectivo].

BACKGROUND: Breast cancer subtype classification according to hormone receptors (HR) and human epidermal growth factor receptor 2 (HER2) using immunohistochemistry is the standard practice for therapeutic decision making. OBJECTIVE: To design future studies information on characteristics and survival of each subtype is essential. METHOD: We conducted a retrospective study to analyze clinical and pathologic features as well as survival data according to breast cancer immunohistochemistry subtype. RESULTS: There were 211 women with a RH(+)/HER2(-) breast cancer subtype, 53 HR(+)/HER2(+), 16 HER2(+) and 23 HR(-)/HER2(-), with a median overall survival in months of 39 (20.5-62.7), 42 (25.5-65), 42 (13.7-67.7) and 26 (11-78), respectively, for a 3.7 hazard ratio of death (95% Confidence Interval [CI]: 1.3-10.3) for the triple negative group as compared to the HR(+)/HER2(-) group (p = 0.01). CONCLUSIONS: HR positive subtypes by immunohistochemistry where most frequent and showed a greater overall survival compared to the triple negative subtype.

ANTECEDENTES: La clasificación del cáncer de mama en subtipos mediante la expresión de receptores hormonales (RH) y del receptor 2 del factor de crecimiento epidérmico humano (HER2) por inmunohistoquímica (IHQ) es una práctica estándar para la toma de decisiones terapéuticas. OBJETIVO: Conocer las características y supervivencia de cada subtipo de pacientes, que es indispensable para poder diseñar futuros estudios. MÉTODO: Realizamos un estudio retrospectivo evaluando las características clinicopatológicas y la supervivencia por subtipo mediante IHQ en mujeres con cáncer de mama. RESULTADOS: 211 mujeres con cáncer de mama RH(+)/HER2(­), 53 con RH(+)/HER2(+), 16 con HER2(+) y 23 con RH(­)/HER2(­), con una mediana de supervivencia global en meses de 39 (20.5-62.7), 42 (25.5-65), 42 (13.7-67.7) y 26 (11-78), respectivamente, para un cociente de riesgo (HR por sus siglas en inglés, Hazard Ratio): 3.7 (IC 95%: 1.3-10.3) en el grupo triple negativo comparado con RH(+)/HER2(­) (p = 0.01). CONCLUSIÓN: Los subtipos con RH positivos por IHQ son los más frecuentes y este grupo de pacientes tienen una mejor supervivencia global comparada con las pacientes triple negativo.

Breast cancer survival by immunohistochemistry-determined subtype: A retrospective study.

BACKGROUND: Breast cancer subtype classification according to hormone receptors (HR) and human epidermal growth factor receptor 2 (HER2) using immunohistochemistry is the standard practice for therapeutic decision making. OBJECTIVE: To design future studies information on characteristics and survival of each subtype is essential. METHOD: We conducted a retrospective study to analyze clinical and pathologic features as well as survival data according to breast cancer immunohistochemistry subtype. RESULTS: There were 211 women with a RH(+)/HER2(-) breast cancer subtype, 53 HR(+)/HER2(+), 16 HER2(+) and 23 HR(-)/HER2(-), with a median overall survival in months of 39 (20.5-62.7), 42 (25.5-65), 42 (13.7-67.7) and 26 (11-78), respectively, for a 3.7 hazard ratio of death (95% Confidence Interval [CI]: 1.3-10.3) for the triple negative group as compared to the HR(+)/HER2(-) group (p = 0.01). CONCLUSIONS: HR positive subtypes by immunohistochemistry where most frequent and showed a greater overall survival compared to the triple negative subtype.

Quantitative microbial risk assessment of Cryptosporidium and Giardia in well water from a native community of Mexico.

Cryptosporidium and Giardia are gastrointestinal disease-causing organisms transmitted by the fecal-oral route, zoonotic and prevalent in all socioeconomic segments with greater emphasis in rural communities. The goal of this study was to assess the risk of cryptosporidiosis and giardiasis of Potam dwellers consuming drinking water from communal well water. To achieve the goal, quantitative microbial risk assessment (QMRA) was carried out as follows: (a) identification of Cryptosporidium oocysts and Giardia cysts in well water samples by information collection rule method, (b) assessment of exposure to healthy Potam residents, (c) dose-response modelling, and (d) risk characterization using an exponential model. All well water samples tested were positive for Cryptosporidium and Giardia. The QMRA results indicate a mean of annual risks of 99:100 (0.99) for cryptosporidiosis and 1:1 (1.0) for giardiasis. The outcome of the present study may drive decision-makers to establish an educational and treatment program to reduce the incidence of parasite-borne intestinal infection in the Potam community, and to conduct risk analysis programs in other similar rural communities in Mexico.

[Laparoscopic hysterectomy assisted with robot. Report of first case in Mexico ]. / Histerectomía laparoscópica asistida con robot. Reporte del primer caso en Mexico.

UNLABELLED: Some 15 years ago since the DaVinci system is launched in the market and since then has been gaining ground in the field of surgery. There have been published case series and large casuisticals comparing the benefits from robotic surgery versus laparoscopic. In 2005 the Food & Drug Administration (FDA) approves its use for gynecological surgery. In Mexico, we have no experience in the use of this technology in this field of medicine. To describe the first laparoscopic hysterectomy case assisted with a robot (LHAR) intervened in Mexico, the results and review of the literature reported at the global level. CLINICAL CASE: this is a 47 year-old patient with clinical and ultrasonographic diagnosis of uterine fibroids of large items, who is scheduled for laparoscopic hysterectomy assisted with robot at Hospital Angeles del Pedregal in May of 2014. It examines the parameters of surgical time, transoperative bleeding, surgical complications, postoperative pain and hospital stay. It is also a review of the literature and compared the results obtained with what is reported in the literature world. The surgery had a duration of 2 hours 35 minutes. Blood loss was less than 50 mL. There were no complications and the patient had an EVA test of 2 at 24 hours after surgery. Hospital stay was 2 days. Laparoscopic hysterectomy assisted with a robot is a reliable procedure according to what is reported at the global level, offering benefits to both the surgeon and the patient.

Plasma membrane curvature regulates the formation of contacts with the endoplasmic reticulum.

Contact sites between the endoplasmic reticulum (ER) and plasma membrane (PM) play a crucial role in governing calcium regulation and lipid homeostasis. Despite their significance, the factors regulating their spatial distribution on the PM remain elusive. Inspired by observations in cardiomyocytes, where ER-PM contact sites concentrate on tubular PM invaginations known as transverse tubules, we hypothesize that PM curvature plays a role in ER-PM contact formation. Through precise control of PM invaginations, we show that PM curvatures locally induce the formation of ER-PM contacts in cardiomyocytes. Intriguingly, the junctophilin family of ER-PM tethering proteins, specifically expressed in excitable cells, is the key player in this process, whereas the ubiquitously expressed extended synaptotagmin-2 does not show a preference for PM curvature. At the mechanistic level, we find that the low-complexity region (LCR) and membrane occupation and recognition nexus (MORN) motifs of junctophilins can bind independently to the PM, but both the LCR and MORN motifs are required for targeting PM curvatures. By examining the junctophilin interactome, we identify a family of curvature-sensing proteins-Eps15 homology domain-containing proteins-that interact with the MORN_LCR motifs and facilitate the preferential tethering of junctophilins to curved PM. These findings highlight the pivotal role of PM curvature in the formation of ER-PM contacts in cardiomyocytes and unveil a mechanism for the spatial regulation of ER-PM contacts through PM curvature modulation.

Membrane Curvature Promotes ER-PM Contact Formation via Junctophilin-EHD Interactions.

Contact sites between the endoplasmic reticulum (ER) and the plasma membrane (PM) play a crucial role in governing calcium regulation and lipid homeostasis. Despite their significance, the factors regulating their spatial distribution on the PM remain elusive. Inspired by observations in cardiomyocytes, where ER-PM contact sites concentrate on tubular PM invaginations known as transverse tubules (T-tubules), we hypothesize that the PM curvature plays a role in ER-PM contact formation. Through precise control of PM invaginations, we show that PM curvatures locally induce the formation of ER-PM contacts in cardiomyocytes. Intriguingly, the junctophilin family of ER-PM tethering proteins, specifically expressed in excitable cells, is the key player in this process, while the ubiquitously expressed extended synaptotagmin 2 does not show a preference for PM curvature. At the mechanistic level, we find that the low complexity region (LCR) and the MORN motifs of junctophilins can independently bind to the PM, but both the LCR and MORN motifs are required for targeting PM curvatures. By examining the junctophilin interactome, we identify a family of curvature-sensing proteins, Eps15-homology domain containing proteins (EHDs), that interact with the MORN_LCR motifs and facilitate junctophilins' preferential tethering to curved PM. These findings highlight the pivotal role of PM curvature in the formation of ER-PM contacts in cardiomyocytes and unveil a novel mechanism for the spatial regulation of ER-PM contacts through PM curvature modulation.

Risk factors associated with suicide attempt as predictors of suicide, Colombia, 2016-2017.

BACKGROUND: Suicidal behaviour is the cause of half of all violent deaths. It is considered to be a public health problem with one million victims a year. Suicide attempt is the most important risk factor. In Colombia, in 2017 the suicide attempt rate was 51.8/100,000 inhabitants, and the fatality rate reached 10.0/100,000. The objective is to identify suicide attempt factors associated with death and determine survival after the attempt for 2 years. MATERIAL AND METHODS: Retrospective cohort study and survival analysis. A total of 42,594 records of the suicide attempt surveillance system databases and 325 records of death by suicide in 2016 and 2017 were analysed. The risk factors were examined and a χ2-test and multivariate analysis and logistic regression were performed. Cumulative survival probability was calculated using the Kaplan-Meier method. A Cox regression model was applied to determine the proportional relationship of the suicide attempt variables that are related to suicide. RESULTS: Men die by suicide 4.5 times more often than women. One in four suicide victims had made at least one prior suicide attempt. The attempt factors related with death by suicide were: male gender (HR = 2.99; 95% CI, 2.27-3.92), adulthood (over 29 years, HR = 2.38; 95% CI, 1.90-2.99), living in a rural area (HR = 2.56; 95% CI, 2.04-3.20), chronic disease history (HR = 2.43; 95% CI, 1.66-3.57) and depression disorder (HR = 1.94; 95% CI, 1.55-2.41). Some 50% of suicide deaths occur up to 560 days after the suicide attempt. CONCLUSIONS: The risk of suicide is highest in male patients, with a history of depression, chronic illness and exposure to heavy workloads.

REC protein family expansion by the emergence of a new signaling pathway.

IMPORTANCE: We explore when and why large classes of proteins expand into new sequence space. We used an unsupervised machine learning approach to observe the sequence landscape of REC domains of bacterial response regulator proteins. We find that within-gene recombination can switch effector domains and, consequently, change the regulatory context of the duplicated protein.

Improved polyketide production in C. glutamicum by preventing propionate-induced growth inhibition.

Corynebacterium glutamicum is a promising host for production of valuable polyketides. Propionate addition, a strategy known to increase polyketide production by increasing intracellular methylmalonyl-CoA availability, causes growth inhibition in C. glutamicum. The mechanism of this inhibition was unclear before our work. Here we provide evidence that accumulation of propionyl-CoA and methylmalonyl-CoA induces growth inhibition in C. glutamicum. We then show that growth inhibition can be relieved by introducing methylmalonyl-CoA-dependent polyketide synthases. With germicidin as an example, we used adaptive laboratory evolution to leverage the fitness advantage of polyketide production in the presence of propionate to evolve improved germicidin production. Whole-genome sequencing revealed mutations in germicidin synthase, which improved germicidin titer, as well as mutations in citrate synthase, which effectively evolved the native glyoxylate pathway to a new methylcitrate pathway. Together, our results show that C. glutamicum is a capable host for polyketide production and we can take advantage of propionate growth inhibition to drive titers higher using laboratory evolution or to screen for production of polyketides.

Staphylococcus haemolyticus and Providencia vermicola Infections Occurring in Farmed Tilapia: Two Potentially Emerging Pathogens.

This work aimed to determine the presence of bacterial pathogens in fish with a clinical picture suggestive of infectious disease in Nile tilapia reared in Chiapas, Mexico. Blood and viscera samples were taken from healthy and diseased animals from commercial farms. Clinical and pathological examinations of each individual were performed and samples were collected for bacteriological studies. The bacterial isolates were identified and characterized by culture, biochemical tests, antibiogram, challenge tests and 16S rRNA sequencing. Staphylococcus haemolyticus and Providencia vermicola were isolated from various diseased organisms. The clinical picture caused by Staphylococcus haemolyticus was characterized by appetite disorders, neurological signs, nodulation or ulceration in different areas and congestion or enlargement of internal organs. Providenciosis in juvenile specimens caused a characteristic picture of hemorrhagic septicemia. Challenge tests performed in healthy organisms revealed that both infections caused higher mortality rates in fish (p < 0.05) compared with non-infected specimens, with 100% survival. There was 100% mortality for animals infected with P. vermicola after three days post infection and 45% for those infected with S. haemolyticus. The isolation and identification of two pathogens involved in an infection process were achieved and cataloged as potential causal agents of disease outbreaks in tilapia farming in Mexico. This is the first report of possible bacterial infection caused by S. haemolyticus and P. vermicola in tilapia farms, which are two uncommon but potentially emerging pathogens for the species.