Prediction model for lower limb amputation in hospitalized diabetic foot patients using classification and regression trees

BACKGROUND

The decision to perform amputation of a limb in a patient with diabetic foot ulcer (DFU) is not an easy task. Prediction models aim to help the surgeon in decision making scenarios. Currently there are no prediction model to determine lower limb amputation during the first 30 days of hospitalization for patients with DFU.

METHODS

Classification And Regression Tree analysis was applied on data from a retrospective cohort of patients hospitalized for the management of diabetic foot ulcer, using an existing database from two Orthopaedics and Traumatology departments. The secondary analysis identified independent variables that can predict lower limb amputation (mayor or minor) during the first 30 days of hospitalization.

RESULTS

Of the 573 patients in the database, 290 feet underwent a lower limb amputation during the first 30 days of hospitalization. Six different models were developed using a loss matrix to evaluate the error of not detecting false negatives. The selected tree produced 13 terminal nodes and after the pruning process, only one division remained in the optimal tree (Sensitivity: 69%, Specificity: 75%, Area Under the Curve: 0.76, Complexity Parameter: 0.01, Error: 0.85). Among the studied variables, the Wagner classification with a cut-off grade of 3 exceeded others in its predicting capacity.

CONCLUSIONS

Wagner classification was the variable with the best capacity for predicting amputation within 30 days. Infectious state and vascular occlusion described indirectly by this classification reflects the importance of taking quick decisions in those patients with a higher compromise of these two conditions. Finally, an external validation of the model is still required.

LEVEL OF EVIDENCE

III.

Cost Effectiveness of Tofacitinib for the Treatment of Moderate to Severe Active Ulcerative Colitis in Colombia

OBJECTIVE

The aim of this study was to evaluate the cost effectiveness of tofacitinib versus other treatment options currently available in Colombia in naïve to biologics (first-line) and exposed to biologics (second-line) patients with moderate to severe active ulcerative colitis (UC).

METHODS

A Markov model was constructed with 8-week cycles, simulating a cohort of patients in a 5-year time horizon. The health states included remission, treatment response, active UC, and colectomy. The transition probabilities for the induction and maintenance phase were obtained from a network meta-analysis, and effectiveness was measured using quality-adjusted life-years (QALYs). Unit costs were derived from official national sources.

RESULTS

For first line, the incremental cost-effectiveness ratio (ICER) per QALY was $883 for tofacitinib and $3619 for infliximab, compared with adalimumab. Sensitivity analysis showed that tofacitinib is cost effective in 45% of the iterations, adalimumab in 5%, and infliximab in 50%. Meanwhile, the ICER of adalimumab was $14,927 compared with tofacitinib in second-line treatment. In the sensitivity analysis, tofacitinib was cost effective in 64% of the iterations, followed by adalimumab in 36%. Infliximab and golimumab were not included due to data limitations in the network meta-analysis of second-line treatment.

CONCLUSION

The analysis suggests that in Colombia, treatment with tofacitinib for patients with moderate-to-severe UC is a cost-effective option in both lines compared with other treatment options.

Selenium and impaired physical function in US and Spanish older adults

Background

Selenium (Se) is a trace element with a narrow safety margin.

Objectives

To evaluate the cross-sectional and longitudinal dose-response association between Se exposure and measures of impaired physical function and disability in older adults.

Design

NHANES 2011–2014 cross-sectional (US, n = 1733, age ≥60 years) and Seniors-ENRICA-2 2017–2019 cross-sectional and longitudinal (Spain, n = 2548 and 1741, respectively, age ≥65 years) data were analyzed. Whole blood and serum Se levels were measured using inductively coupled plasma-mass spectrometry. Lower-extremity performance was assessed with the Short Physical Performance Battery, and muscle weakness with a dynamometer. Incident mobility and agility limitations, and disability in instrumental activities of daily living (IADL) were ascertained with standardized questionnaires. Analyses were adjusted for relevant confounders, including physical activity. Results across studies were pooled using random-effects meta-analysis.

Results

Meta-analyzed odds ratios (95% confidence interval) per log2 increase in whole blood Se were 0.54 (0.32; 0.76) for weakness, 0.59 (0.34; 0.83) for impaired lower-extremity performance, 0.48 (0.31; 0.68) for mobility limitations, 0.71 (0.45; 0.97) for agility limitations, and 0.34 (0.12; 0.56) for disability in at least one IADL. Analyses for serum Se in NHANES showed similar results. Findings suggest the inverse association with grip strength is progressive below 140 μg/L (p-value for non-linear trend in the Seniors-ENRICA-2 study = 0.13), and above 140 μg/L (p-value for non-linear trend in NHANES = 0.11). In the Seniors-ENRICA-2 cohort, with a 2.2 year follow-up period, a doubling in baseline Se levels were associated with a lower incidence of weakness [odds ratio (95% confidence interval): 0.45 (0.22; 0.91)], impaired lower-extremity performance [0.63 (0.32; 1.23)], mobility [0.43 (0.21; 0.91)] and agility [0.38 (0.18; 0.78)] limitations.

Discussion

In US and Spanish older adults, Se concentrations were inversely associated with physical function limitations. Further studies are needed to elucidate underlying mechanisms.

Characterization of inflammatory bowel disease in Colombia: Results of a national register

AIM

To determine the clinical, sociodemographic, and treatment characteristics of inflammatory bowel disease (IBD) in a Colombian population register.

METHODS

A descriptive, analytic, observational, cross-sectional, multicenter study on patients with IBD from 17 hospital centers in 9 Colombian cities was conducted.

RESULTS

A total of 2,291 patients with IBD were documented, 1,813 (79.1%) of whom presented with ulcerative colitis (UC), 456 (19.9%) with Crohn's disease (CD), and 22 with IBD unclassified (0.9%). The UC/CD ratio was 3.9:1. A total of 18.5% of the patients with UC and 47.3% with CD received biologic therapy. Patients with extensive UC had greater biologic therapy use (OR = 2.78, 95% CI: 2.10-3.65, p = 0.000), a higher surgery rate (OR = 5.4, 95% CI: 3.5-8.3, p = 0.000), and greater frequency of hospitalization (OR = 4.34, 95% CI: 3.47-5.44, p = 0.000). Patients with severe UC had greater biologic therapy use (OR = 5.04, 95% CI: 3.75-6.78, p = 0.000), a higher surgery rate (OR = 8.64, 95% CI: 5.4-13.78, p = 0.000), and greater frequency of hospitalization (OR = 28.45, 95% CI: 19.9-40.7, p = 0.000). CD patients with inflammatory disease behavior (B1) presented with a lower frequency of hospitalization (OR = 0.12, 95% CI: 0.07-0.19, p = 0.000), a lower surgery rate (OR = 0.08, 95% CI: 0.043-0.15, p = 0.000), and less biologic therapy use (OR = 0.26, 95% CI: 0.17-0.41, p = 0.000).

CONCLUSION

In Colombia, there is a predominance of UC over CD (3.9:1), as occurs in other Latin American countries. Patients with extensive UC, severe UC, or CD with noninflammatory disease behavior (B2, B3) have a worse prognosis.

Evaluation of functionality of type II toxin-antitoxin systems of Clostridioides difficile R20291

Clostridioides difficile is a nosocomial, Gram-positive, strictly anaerobic, spore-forming pathogen capable of colonizing and proliferating in the human intestine. In bacteria, it has been shown that the Toxin-Antitoxin systems mediate the cellular response to external stress by initiating processes such as biofilm formation and programmed cell death. This work aims to evaluate the functionality of four type II TA modules of Clostridioides difficile R20291. We performed bioinformatic analysis to search for putative TA systems using the TADB platform. Then we performed a heterologous expression assay to evaluate the functionality of these systems. Our results showed that the MazEF and RelBE systems were functional, suggesting that their corresponding toxins possess an endoribonuclease activity. In conclusion, MazEF and RelBE systems of C. difficile R20291 are functional in a heterologous expression system.

Perceived changes in psychological and physical symptoms after hospital clown performances in a cancer setting

Background: The therapeutic role of humor and hospital clowns has become a focus of interest in recent decades. Most of the research in the area has focused on children; here, we explore the influence of clown performances on adult cancer patients, their companions, and health-care staff.Methods: Ninety-nine cancer patients and 113 companions were assessed pre- and post-interventions performed by professional clowns; 31 health professionals were asked about the possible influence of the presence of clowns in hospital on their work.Results: Patients felt that clowning performances helped to reduce their level of psychological symptoms, but not their physical symptoms. Companions reported improvements in all the psychological symptoms explored. Health professionals reported that the presence of clowns in the workplace improved their well-being.Conclusions: Clowning performances helped to improve psychological functioning in all the populations studied, especially in companions. Adult hospitals should consider promoting clowning interventions to improve general well-being.

Keratoacanthoma-like nodules as first manifestation of metastatic epithelioid trophoblastic tumor

Cutaneous metastases are rarely the initial manifestation of a previously undiagnosed malignancy and keratoacanthoma-like lesions are a notoriously unusual presentation pattern of cutaneous dissemination of a primary tumor. Herein, we report a 40-year-old woman presenting to our dermatology department with multiple keratoacanthoma-like scalp nodules. Subsequent investigation determined it to be the first manifestation of a disseminated endometrial epithelioid trophoblastic tumor, eventually causing the patient's death. Epithelioid trophoblastic tumor, a rare form of gestational trophoblastic disease, is a recently described neoplasm whose cutaneous metastasis has not been previously reported in the literature.

Manganese levels in newborns' hair by maternal sociodemographic, dietary and environmental factors

Exposure to manganese (Mn) has been associated with neurodevelopmental problems in children. Mn exposure begins in utero, and maternal sociodemographic, dietary and environmental factors may affect Mn levels in newborns' hair. This study aimed to characterize in utero Mn exposure using Mn levels in newborns' hair as a biomarker of prenatal exposure, and to analyze its relationship with sociodemographic, dietary and environmental factors in the Spanish INMA-Gipuzkoa cohort. Overall, 638 pregnant women were recruited in the first trimester of pregnancy and a hair sample was obtained from 473 newborns. Sociodemographic, dietary and environmental data were recorded through two questionnaires administered in the first and third trimesters of pregnancy. The median Mn concentration in newborns´ hair was 0.31 µg/g (P5 = 0.02; P95 = 1.23). Mn levels in newborns´ hair were associated with smoking during pregnancy (β = 0.222; 95% CI = 0.065-0.379) and with maternal PM_2.5 exposure (β = 0.025; 95% CI = 0.004; 0.047), as well as with cereal and pasta intake in the first trimester of pregnancy (β = 0.002; 95% CI = 0.0004; 0.003). In conclusion, fetal exposure to Mn was associated with smoking and exposure to atmospheric pollution during pregnancy.

Effect of antibiotic treatment on the formation of non-spore Clostridium difficile persister-like cells

Background

The spore is the virulence factor identified to be involved in the recurrence of the disease caused by Clostridium difficile.

Objectives

To demonstrate that lethal antibiotic concentrations induce the appearance of C. difficile persister-like non-spore cells.

Methods

C. difficile and derivative spo0A mutant strains were tested for their susceptibility to antibiotics, as determined using an agar dilution method. Persister-cell generation was determined for all strains using up to 10 × the MIC of every antibiotic for up to 6 days.

Results

Using up to 10 × the MIC of every antibiotic, we were able to induce the appearance of persister-like behaviour since biphasic killing curves could be observed in response to treatment antibiotics.

Conclusions

To the best of our knowledge, this work provides, for the first time, experimental evidence of the appearance of C. difficile persister-like cells, opening a new research avenue in the pathogenesis of this nosocomial pathogen.

Religiöse und spirituelle Einstellungen in Bezug auf bindungstheoretische Aspekte bei Somatoformen Störungen

Die Religiosität bzw. Spiritualität können als bedeutsame Elemente in der Bewältigung lebensbedrohlicher oder anderer Erkrankungen angesehen werden. Bei Patienten mit „Somatoformen Störungen” (SFD) wurde der Zusammenhang zwischen Religiosität und den einzelnen vorgefundenen Bindungsstile im Sinne der Bindungstheorie näher untersucht. 76 Patienten im Alter von 42,2 Jahre (± 9,9) wurden für die Interviews und Fragebögen rekrutiert. Das Ausmaß der religiösen Einstellungen und Praktiken wurde mittels der deutschen Version des „Systems of Belief Inventory” (SBI-15R-D) erhoben, zusätzlich die BFKE-Skala (Bielefelder Fragebogen zu Klientenerwartung-Skala) zur Erfassung des Bindungsstiles. Die überwiegende Zahl der Patienten mit SFD ist „unsicher” gebunden (88,18%), der Rest ist „sicher” gebunden (11,96%). Die Gruppe der „vermeidend-kooperativ” gebundenen Patienten ist religiöser als die übrigen Bindungsgruppen und je „ambivalent-anklammernder” der Bindungsstil ist, desto religiöser sind die Patienten. Es gibt also Hinweise für eine Beziehung zwischen der Religiosität und dem Bindungsstil bei Patienten mit SFD.

Interstitial granulomatous dermatitis in a patient with chronic hepatitis C and mixed cryoglobulinemia

A 55-year-old man presented with a history of asymptomatic, bilateral, figurate dermatosis consisting of erythematous, annular, linear, andarciform, indurated nodules and plaques on the lateral walls of thorax, flanks, and hypogastrium. His medical history was positive for chronic hepatitis C. Skin biopsy was compatible with the diagnosisof interstitial granulomatous dermatitis. Additionalinvestigation revealed positive rheumatoid factor, antinuclear antibodies, and cryoglobulins. Thepatient started treatment with high-potency topical corticosteroid. After 12 weeks of treatment there was a partial clinical improvement of thedermatosis. Interstitial granulomatous dermatitis exhibits a distinct histopathological pattern with a diverse clinical appearance, which can be associated with autoimmune systemic diseases, neoplasms, several drugs, and infections. Optimal therapy for this condition is yet to be established, but topical corticosteroids have been a mainstay of treatment.

Prevalence and Penetrance of BRCA1 and BRCA2 Germline Mutations in Colombian Breast Cancer Patients

Pathogenic BRCA1/2 germline mutations confer high risks of breast and ovarian cancer to women of European ancestry. Characterization of BRCA1/2 mutations in other ethnic groups is also medically important. We comprehensively screened 68 Colombian breast/ovarian cancer families for small-range mutations, 221 families for large-genomic rearrangements, and 1,022 unselected breast cancer cases for Colombian founder mutations in BRCA1/2. The risk of cancer among relatives of mutation carriers and the mutation penetrance were estimated by survival analysis. Identified BRCA2 mutations included 6310delGA and the recurrent 1991del4 mutations. A novel large BRCA2 deletion was found in 0.9% of the screened families. Among unselected breast cancer cases, 3.3% tested positive for BRCA1/3450del4, 2.2% for BRCA1/A1708E, 1.1% for BRCA2/3034del4, and 0.4% for BRCA2/1991del4. Female relatives of carriers of BRCA1/2 founder mutations showed a 5.90 times higher risk of breast cancer, when the woman herself carried a BRCA1 mutation compared to a non-carrier (95% CI 2.01–17.3). The estimated cumulative risk of breast cancer by age 70 years for BRCA1 mutations carriers was 14% (95% CI 5–38) compared to 3% for the general Colombian population (relative risk of breast cancer 4.05). Together with known founder mutations, reported novel variants may ease a cost-effective BRCA1/2 screening in women with Colombian ancestry.

Molecular Assessment of Microcirculation Injury in Formalin-Fixed Human Cardiac Allograft Biopsies With Antibody-Mediated Rejection

Precise diagnosis of antibody-mediated rejection (AMR) in cardiac allograft endomyocardial biopsies (EMBs) remains challenging. This study assessed molecular diagnostics in human EMBs with AMR. A set of 34 endothelial, natural killer cell and inflammatory genes was quantified in 106 formalin-fixed, paraffin-embedded EMBs classified according to 2013 International Society for Heart and Lung Transplantation (ISHLT) criteria. The gene set expression was compared between ISHLT diagnoses and correlated with donor-specific antibody (DSA), endothelial injury by electron microscopy (EM) and prognosis. Findings were validated in an independent set of 57 EMBs. In the training set (n = 106), AMR cases (n = 70) showed higher gene set expression than acute cellular rejection (ACR; n = 21, p < 0.001) and controls (n = 15, p < 0.0001). Anti-HLA DSA positivity was associated with higher gene set expression (p = 0.01). Endothelial injury by electron microscopy strongly correlated with gene set expression, specifically in AMR cases (r = 0.62, p = 0.002). Receiver operating characteristic curve analysis for diagnosing AMR showed greater accuracy with gene set expression (area under the curve [AUC] = 79.88) than with DSA (AUC = 70.47) and C4d (AUC = 70.71). In AMR patients (n = 17) with sequential biopsies, increasing gene set expression was associated with inferior prognosis (p = 0.034). These findings were confirmed in the validation set. In conclusion, biopsy-based molecular assessment of antibody-mediated microcirculation injury has the potential to improve diagnosis of AMR in human cardiac transplants.

Characterization and expression analysis of Toll-like receptor 3 cDNA from Atlantic salmon (Salmo salar)

Innate pathway activation is fundamental for early anti-viral defense in fish, but currently there is insufficient understanding of how salmonid fish identify viral molecules and activate these pathways. The Toll-like receptor (TLR) is believed to play a crucial role in host defense of pathogenic microbes in the innate immune system. In the present study, the full-length cDNA of Salmo salar TLR3 (ssTLR3) was cloned. The ssTLR3 cDNA sequence was 6071 bp long, containing an open reading frame of 2754 bp and encoding 971 amino acids. The TLR group motifs, such as leucine-rich repeat (LRR) domains and Toll-interleukin-1 receptor (TIR) domains, were maintained in ssTLR3, with sixteen LRR domains and one TIR domain. In contrast to descriptions of the TLR3 in rainbow trout and the murine (TATA-less), we found a putative TATA box in the proximal promoter region 29 bp upstream of the transcription start point of ssTLR3. Multiple-sequence alignment analysis of the ssTLR3 protein-coding sequence with other known TLR3 sequences showed the sequence to be conserved among all species analyzed, implying that the function of the TLR3 had been sustained throughout evolution. The ssTLR3 mRNA expression patterns were measured using real-time PCR. The results revealed that TLR3 is widely expressed in various healthy tissues. Individuals challenged with infectious pancreatic necrosis virus and immunostimulated with polyinosinic:polycytidylic acid exhibited increased expression of TLR3 at the mRNA level, indicating that ssTLR3 may be involved in pathogen recognition in the early innate immune system.

Toxicological importance of human biomonitoring of metallic and metalloid elements in different biological samples

Human biomonitoring has become an important tool for the assessment of internal doses of metallic and metalloid elements. These elements are of great significance because of their toxic properties and wide distribution in environmental compartments. Although blood and urine are the most used and accepted matrices for human biomonitoring, other non-conventional samples (saliva, placenta, meconium, hair, nails, teeth, breast milk) may have practical advantages and would provide additional information on health risk. Nevertheless, the analysis of these compounds in biological matrices other than blood and urine has not yet been accepted as a useful tool for biomonitoring. The validation of analytical procedures is absolutely necessary for a proper implementation of non-conventional samples in biomonitoring programs. However, the lack of reliable and useful analytical methodologies to assess exposure to metallic elements, and the potential interference of external contamination and variation in biological features of non-conventional samples are important limitations for setting health-based reference values. The influence of potential confounding factors on metallic concentration should always be considered. More research is needed to ascertain whether or not non-conventional matrices offer definitive advantages over the traditional samples and to broaden the available database for establishing worldwide accepted reference values in non-exposed populations.

Determination of toxic elements (mercury, cadmium, lead, tin and arsenic) in fish and shellfish samples. Risk assessment for the consumers

Although fish intake has potential health benefits, the presence of metal contamination in seafood has raised public health concerns. In this study, levels of mercury, cadmium, lead, tin and arsenic have been determined in fresh, canned and frozen fish and shellfish products and compared with the maximum levels currently in force. In a further step, potential human health risks for the consumers were assessed. A total of 485 samples of the 43 most frequently consumed fish and shellfish species in Andalusia (Southern Spain) were analyzed for their toxic elements content. High mercury concentrations were found in some predatory species (blue shark, cat shark, swordfish and tuna), although they were below the regulatory maximum levels. In the case of cadmium, bivalve mollusks such as canned clams and mussels presented higher concentrations than fish, but almost none of the samples analyzed exceeded the maximum levels. Lead concentrations were almost negligible with the exception of frozen common sole, which showed median levels above the legal limit. Tin levels in canned products were far below the maximum regulatory limit, indicating that no significant tin was transferred from the can. Arsenic concentrations were higher in crustaceans such as fresh and frozen shrimps. The risk assessment performed indicated that fish and shellfish products were safe for the average consumer, although a potential risk cannot be dismissed for regular or excessive consumers of particular fish species, such as tuna, swordfish, blue shark and cat shark (for mercury) and common sole (for lead).

Salmonella enterica serovar Typhimurium BaeSR two-component system positively regulates sodA in response to ciprofloxacin

In response to antibiotics, bacteria activate regulatory systems that control the expression of genes that participate in detoxifying these compounds, like multidrug efflux systems. We previously demonstrated that the BaeSR two-component system from Salmonella enterica serovar Typhimurium (S. Typhimurium) participates in the detection of ciprofloxacin, a bactericidal antibiotic, and in the positive regulation of mdtA, an efflux pump implicated in antibiotic resistance. In the present work, we provide further evidence for a role of the S. Typhimurium BaeSR two-component system in response to ciprofloxacin treatment and show that it regulates sodA expression. We demonstrate that, in the absence of BaeSR, the transcript levels of sodA and the activity of its gene product are lower. Using electrophoretic mobility shift assays and transcriptional fusions, we demonstrate that BaeR regulates sodA by a direct interaction with the promoter region.

ompW is cooperatively upregulated by MarA and SoxS in response to menadione

OmpW is a minor porin whose biological function has not been clearly defined. Evidence obtained in our laboratory indicates that in Salmonella enterica serovar Typhimurium the expression of OmpW is activated by SoxS upon exposure to paraquat and it is required for resistance. SoxS belongs to the AraC family of transcriptional regulators, like MarA and Rob. Due to their high structural similarity, the genes under their control have been grouped in the mar/sox/rob regulon, which presents a DNA-binding consensus sequence denominated the marsox box. In this work, we evaluated the role of the transcription factors MarA, SoxS and Rob of S. enterica serovar Typhimurium in regulating ompW expression in response to menadione. We determined the transcript and protein levels of OmpW in different genetic backgrounds; in the wild-type and Δrob strains ompW was upregulated in response to menadione, while in the ΔmarA and ΔsoxS strains the induction was abolished. In a double marA soxS mutant, ompW transcript levels were lowered after exposure to menadione, and only complementation in trans with both genes restored the positive regulation. Using transcriptional fusions and electrophoretic mobility shift assays with mutant versions of the promoter region we demonstrated that two of the predicted sites were functional. Additionally, we demonstrated that MarA increases the affinity of SoxS for the ompW promoter region. In conclusion, our study shows that ompW is upregulated in response to menadione in a cooperative manner by MarA and SoxS through a direct interaction with the promoter region.

Placental concentrations of heavy metals in a mother-child cohort

Heavy metals are environmental contaminants with properties known to be toxic for wildlife and humans. Despite strong concerns about their harmful effects, little information is available on intrauterine exposure in humans. The aim of this study was to evaluate prenatal exposure to As, Cd, Cr, Hg, Mn, and Pb and its association with maternal factors in a population-based mother-child cohort in Southern Spain. Between 2000 and 2002, 700 pregnant women were recruited and 137 placentas from the cohort were randomly selected and analyzed for the selected metals by atomic absorption. Maternal sociodemographic and lifestyle factors were obtained by questionnaire after delivery. Bivariate analysis and multivariate linear regression were performed. Cd and Mn concentrations were detected in all placentas, while Cr, Pb, and Hg were found in 98.5%, 35.0%, and 30.7% of samples, respectively. The highest concentrations were observed for Pb (mean: 94.80 ng/g wet weight of placenta), followed by Mn (63.80 ng/g), Cr (63.70 ng/g), Cd (3.45 ng/g), and Hg (0.024 ng/g). Arsenic was not detected in any sample. Gestational age and smoking during pregnancy were associated with placental Cd concentrations, while no factor appeared to influence concentrations of Cr, Hg, Mn, or Pb. In comparison to results of European studies, these concentrations are in a low-intermediate position. Studies are required to investigate the factors contributing to early exposure to heavy metals and to determine how placental transfer of these toxic compounds may affect children's health.

cAMP receptor protein (CRP) positively regulates the yihU-yshA operon in Salmonella enterica serovar Typhi

Salmonella enterica serovar Typhi (S. Typhi) is the aetiological agent of typhoid fever in humans. This bacterium is also able to persist in its host, causing a chronic disease by colonizing the spleen, liver and gallbladder, in the last of which the pathogen forms biofilms in order to survive the bile. Several genetic components, including the yihU-yshA genes, have been suggested to be involved in the survival of Salmonella in the gallbladder. In this work we describe how the yihU-yshA gene cluster forms a transcriptional unit regulated positively by the cAMP receptor global regulator CRP (cAMP receptor protein). The results obtained show that two CRP-binding sites on the regulatory region of the yihU-yshA operon are required to promote transcriptional activation. In this work we also demonstrate that the yihU-yshA transcriptional unit is carbon catabolite-repressed in Salmonella, indicating that it forms part of the CRP regulon in enteric bacteria.