Methicillin-resistant (MR) Staphylococcus aureus (SA) and others, except for Staphylococcus aureus (SOSA), are common in healthcare-associated infections. SOSA encompass largely coagulase-negative staphylococci, including coagulase-positive staphylococcal species. Biofilm formation is encoded by the icaADBC operon and is involved in virulence. mecA encodes an additional penicillin-binding protein (PBP), PBP2a, that avoids the arrival of β-lactams at the target, found in the staphylococcal cassette chromosome mec (SCCmec). This work aims to detect mecA, the bap gene, the icaADBC operon, and types of SCCmec associated to biofilm in MRSA and SOSA strains. A total of 46% (37/80) of the strains were S. aureus, 44% (35/80) S. epidermidis, 5% (4/80) S. haemolyticus, 2.5% (2/80) S. hominis, 1.25% (1/80) S. intermedius, and 1.25% (1/80) S. saprophyticus. A total of 85% were MR, of which 95.5% showed mecA and 86.7% β-lactamase producers; thus, Staphylococcus may have more than one resistance mechanism. Healthcare-associated infection strains codified type I-III genes of SCCmec; types IV and V were associated to community-acquired strains (CA). Type II prevailed in MRSA mecA strains and type II and III in MRSOSA (methicillin-resistant staphylococci other than Staphylococcus aureus). The operon icaADBC was found in 24% of SA and 14% of SOSA; probably the arrangement of the operon, fork formation, and mutations influenced the variation. Methicillin resistance was mainly mediated by the mecA gene; however, there may be other mechanisms that also participate, since biofilm production is related to genes of the icaADBC operon and methicillin resistance was not associated with biofilm production. Therefore, it is necessary to strengthen surveillance to prevent the spread of these outbreaks both in the nosocomial environment and in the community.

Early and accurate diagnoses of pathogenic microorganisms is essential to correctly identify diseases, treating infections, and tracking disease outbreaks associated with microbial infections, to develop precautionary measures that allow a fast and effective response in epidemics and pandemics, thus improving public health. Aptamers are a class of synthetic nucleic acid molecules with the potential to be used for medical purposes, since they can be directed towards any target molecule. Currently, the use of aptamers has increased because they are a useful tool in the detection of specific targets. We present a brief review of the use of aptamers to detect and identify bacteria or even some toxins with clinical importance. This work describes the advances in the technology of aptamers, with the purpose of providing knowledge to develop new aptamers for diagnoses and treatment of different diseases caused by infectious microorganisms.

Stenotrophomonas maltophilia is a multidrug-resistant Gram-negative bacillus associated with nosocomial infections in intensive care units, and nowadays, its acquired resistance to trimethoprim–sulfamethoxazole (SXT) by sul genes within class 1 integrons is a worldwide health problem. Biofilm and motility are two of the major virulence factors in this bacterium and are auto-induced by the diffusible signal factor (DSF). In recent studies, retinoids have been used to inhibit (Quorum Quenching) these virulence factors and for their antimicrobial effect. The aim was to reduce biofilm formation and motility with retinoic acid (RA) in S. maltophilia SXT-resistant strains. Eleven SXT-resistant strains and two SXT-susceptible strains were tested for biofilm formation/reduction and planktonic/sessile cell viability with RA and SXT-MIC₅₀/RA; motility (twitching, swimming, swarming) was measured with/without RA; and MLST typing was determined. The biofilm formation of the strains was classified as follows: 15.38% (2/13) as low, 61.54% (8/13) as moderate, and 23.08% (3/13) as high. It was significantly reduced with RA and SXT-MIC₅₀/RA (p < 0.05); cell viability was not significantly reduced with RA (p > 0.05), but it was with SXT-MIC₅₀/RA (p < 0.05); and swimming (p < 0.05) and swarming (p < 0.05) decreased significantly. MLST typing showed the first and novel strains of Mexican S. maltophilia registered in PubMLST (ST479-485, ST497, ST23, ST122, ST175, ST212, and ST300). In conclusion, RA reduced biofilm formation and motility without affecting cell viability; furthermore, antimicrobial synergism with SXT-MIC₅₀/RA in different and novel STs of S. maltophilia was observed.

Introduction: Successful pulp treatment is achieved with proper disinfection of root canals, which is difficult to achieve completely in primary teeth due to the complex anatomy. Antimicrobial pastes can be an effective treatment alternative, reducing work time and material use. Methods: Reference strain Enterococcus faecalis ATCC 51299 was used. Bacterial suspensions adjusted to 0.5 McFarland standard were incubated for 24 h at 37°C with both pastes. Serial dilutions (10-1-10⁻¹²) were done, and colony-forming units (CFU/ml) were determined. Results: Both pastes inhibited bacterial growth, with statistically significant differences (p<0.0001). The CTZ (LAB) paste demonstrated greater antimicrobial effectiveness compared to the CTZ(UNAM) paste and the Ultrapex® paste. Conclusions: CTZ and Ultrapex® pastes demonstrated antimicrobial activity against E. faecalis, with CTZ being more effective. CTZ represents a promising alternative for pulpal treatment in primary teeth.

The trematode Clinostomum marginatum, secretes excretory-secretory products (ESPs) which have the potential to increase the viability and antioxidant activity of probiotic strains. The aim of this study was to identify the ESP profile of C. marginatum and to evaluate its anti-inflammatory activity in RAW 264.7 macrophages, as well as its effect on the viability and antioxidant activity of a consortium of bacteria comprising Lactobacillus and/or Bifidobacterium. C. marginatum was maintained in RPMI-1640 medium for ESP collection. Anti-inflammatory activity was assessed in LPS-stimulated RAW264.7 cells treated with 800 µg/mL of ESPs, measuring cell viability, nitric oxide production, and the relative expression of pro-inflammatory cytokines (IL-6, TNF-α, INF-γ) and the COX-2 gene by qPCR. The influence of ESPs (800–1600 µg/mL) on probiotic viability and antioxidant activity was determined using MTT, DPPH, hydroxyl, and superoxide radical scavenging assays. C. marginatum showed 74% survival in vitro, and SDS-PAGE analysis revealed three major protein bands in the ESPs (47, 54, and 58 kDa). ESP treatment significantly reduced nitric oxide and the mRNA expression of pro-inflammatory markers in LPS-activated macrophages. ESPs supplemented at 1200 µg/mL optimized the growth kinetics of Lactobacillus (specific growth rate μ_L = 1.12 h⁻¹, doubling time t_d = 0.62 h) and Bifidobacterium (μ_B = 1.09 h⁻¹, t_d = 0.63 h) compared to control conditions. In conclusion, ESPs from C. marginatum exhibited significant anti-inflammatory and antioxidant effects while enhancing bacterial viability, which positions them as promising candidates for biotherapeutics agents in the management of inflammatory control and gut microbiota modulation.