China
Africa
Explore chapters and articles related to this topic
Approaches for Identification and Validation of Antimicrobial Compounds of Plant Origin: A Long Way from the Field to the Market
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Lívia Maria Batista Vilela, Carlos André dos Santos-Silva, Ricardo Salas Roldan-Filho, Pollyanna Michelle da Silva, Marx de Oliveira Lima, José Rafael da Silva Araújo, Wilson Dias de Oliveira, Suyane de Deus e Melo, Madson Allan de Luna Aragão, Thiago Henrique Napoleão, Patrícia Maria Guedes Paiva, Ana Christina Brasileiro-Vidal, Ana Maria Benko-Iseppon
As described above, it is necessary to determine the IMC values in many cases, which can be done through macrodilution and microdilution tests. In both cases, the inoculum can be prepared in a similar way. For bacteria, the inoculum must be prepared from colonies grown on agar plates. These colonies are transferred to the appropriate liquid culture medium and are incubated until the turbidity of a 0.5 solution on the McFarland scale is reached or exceeded, equivalent to approximately 1 to 2 × 108 Colony-Forming Units (CFU)/mL. The turbidity of the active growth culture can be adjusted with sterile saline solution (NaCl 0.9%) or culture medium. For fastidious organisms, it is recommended to prepare the inoculum by making a direct suspension, in saline or culture medium, of colonies grown on an agar plate for 18–24 hours (CLSI 2016; 2018). In the case of yeast fungus, the microorganisms must be subcultured in sterile tubes containing, for example, Sabouraud Dextrose Agar or Potato Dextrose Agar for 24 to 48 hours at 30°C. As with bacteria, colonies must be suspended in sterile saline and the cell density adjusted to 0.5 on the McFarland scale. The working suspension is produced by a 1:100 dilution, providing a standard yeast suspension containing from 1 to 5 × 106 CFU/mL (CLSI 2017a).
Antimicrobial Preservative Efficacy and Microbial Content Testing*
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Scott V.W. Sutton, Philip A. Geis
A number of factors can influence the results of assays of preservation efficacy. Russell provides a review of some of these factors (66,67), correctly noting that the condition of the challenge microorganism and the conditions of the assays can play large roles in the measured activity of an antimicrobial. While directing their discussion to antibiotic test methodologies, Gilbert et al. presented an excellent discussion of preservation issues in 1991 (68). The central theme of their discussion is that the treatment received by an inoculum will affect a microorganism’s susceptibility to antimicrobial agents, particularly the manner in which it was harvested and the medium in which it was suspended.
Helicobacter pylori
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
Factors affecting treatment effectiveness: Development of resistance during treatment.Inoculum effect.Protective effect gastric mucus layer.Intracellular location bacteria.Subpopulation of resistant strains.Compliance to treatment.Age <60 years, type of gastritis, presence of non-ulcer dyspepsia, CYP 2C19 polymorphisms (affecting proton pump inhibitor [PPI] metabolism), smoking and increased body mass index.But most importantly, compliance, high gastric acidity, high bacterial load and bacterial strains, but the most important is the increase in H. pylori resistance to clarithromycin.
Antibacterial activity and physicochemical properties of a sealer containing copaiba oil
Published in Biofouling, 2023
Lara Rodrigues Schneider, Andressa da Silva Barboza, Juliana Silva Ribeiro de Andrade, Daniela Coelho dos Santos, Carlos Enrique Cuevas-Suárez, Evandro Piva, Angela Diniz Campos, Rafael Guerra Lund
This test used strains of E. faecalis (ATCC 4083) and S. aureus (ATCC 19095). E. faecalis was cultured overnight at 37 °C in tryptic soy agar (TSA) plates in an anaerobic atmosphere and then inoculated in tryptic soy broth (TSB). S. aureus was cultured overnight at 37 °C in tryptic soy agar (TSA) plates in an aerobic atmosphere and then inoculated in tryptic soy broth (TSB). For both microorganisms, culture suspensions were prepared for inoculum standardization. The suspensions were diluted in 0.9% saline solution on a 0.5 MacFarland scale to obtain approximately 1.5 × 108 Colony Forming Units (CFU/mL) for bacteria and 2.0 × 106 CFU/mL for yeast and, the bacterial turbidity was adjusted to an optical density of 0.5 at 600 nm.
Antimicrobial effectiveness of root canal sealers against Enterococcus faecalis
Published in Biomaterial Investigations in Dentistry, 2022
Paola Castillo-Villagomez, Elizabeth Madla-Cruz, Fanny Lopez-Martinez, Idalia Rodriguez-Delgado, Jorge Jaime Flores-Treviño, Guadalupe Ismael Malagon-Santiago, Myriam Angelica de La Garza-Ramos
The root canal sealers were prepared according to the manufacturers' recommendations. Endosequence, Bioroot, and AH Plus were mixed and a coating was applied to the sidewall of the agar plates used for the experiments. E. faecalis ATCC 29212, which has been used to test the activity of antimicrobial endodontic materials, was used [14,15]. This isolate was obtained from the UANL Center for Research and Development in Health Sciences. Bacteria were grown aerobically from frozen stored cultures in brain heart infusion (BHI) broth at 37 °C. Laboratory prepared broths were used according to the manufacturer's specifications. Cells were harvested by centrifugation and resuspended in fresh medium. The inoculum was prepared by resuspending washed cells at predetermined optical densities related to known concentrations.
Methicillin Resistant Staphylococcus aureus and public fomites: a review
Published in Pathogens and Global Health, 2020
Ziad W Jaradat, Qutaiba O Ababneh, Sherin T Sha’aban, Ayesha A Alkofahi, Duaa Assaleh, Anan Al Shara
A critical factor that allows the transmission of MRSA from a person to the environment and then to other people, is the pathogen’s ability to survive on different types of surfaces under low humidity conditions, and its persistence on these surfaces for extended periods [39,183]. It is noteworthy that the antibiotic-resistance trait of MRSA does not affect the length of the survival period on fomites compared to, for example, Methicillin-sensitive S. aureus (MSSA). Rather, MRSA survival time on fomites is affected by inoculum concentration [184]. This is consistent with the phenomenon of cryptic growth; where cells in a nutrient-limited environment will live on the remains of surrounding dying cells, and thus, an increased inoculum concentration will provide more dying cells for longer periods of time to sustain the lives of the remaining bacteria [185]. However, others reported contradictory data on the differences in the survival ability/length of MRSA vs MSSA. For instance, Wagenvoort and Penders (1997) reported the survival of an MRSA linage for 175 days in hospital dust while an MSSA linage survived only for 4 weeks under the same conditions [186]. Zarpellon et al. (2015) reported the survival of MRSA and vancomycin-resistant S. aureus (VRSA) on vinyl floors and formica for 40–45 days while on latex for only 2 days while MSSA survived on latex for only one day (Table 5) [187].