Inglês para Microbiologia: Vocabulário e Frases Essenciais

"gram-positive"

describes bacteria that retain the crystal violet dye during Gram staining, indicating a thick peptidoglycan cell wall

"Staphylococcus aureus is a gram-positive coccus commonly isolated from skin and soft-tissue infections."

"gram-negative"

describes bacteria that lose the crystal violet stain and appear pink after counterstaining, indicating a thin peptidoglycan layer with an outer membrane

"Escherichia coli is a gram-negative rod that forms part of the normal intestinal flora but can cause urinary tract infections."

"obligate anaerobe"

a microorganism that cannot survive in the presence of oxygen and obtains energy through anaerobic metabolism

"Clostridium perfringens is an obligate anaerobe responsible for gas gangrene in deep wound infections."

"bacterial endospore"

a highly resistant, dormant structure produced by certain bacteria, enabling survival under extreme environmental conditions

"Bacillus anthracis forms bacterial endospores that remain viable in soil for decades."

"peptidoglycan"

the rigid polymer layer that forms the structural backbone of most bacterial cell walls, composed of sugars cross-linked by short peptide chains

"Beta-lactam antibiotics inhibit the enzymes that cross-link peptidoglycan, weakening the cell wall and leading to lysis."

"binary fission"

the primary method of bacterial reproduction, in which a cell grows to twice its size and divides into two identical daughter cells

"Under optimal conditions, E. coli undergoes binary fission approximately every 20 minutes."

"biofilm"

a structured community of microorganisms encased in a self-produced matrix of polysaccharides, proteins, and DNA, attached to a surface

"Chronic catheter-associated infections are often caused by biofilm-forming bacteria that are resistant to antibiotic treatment."

"flagellum"

a whip-like appendage extending from the bacterial cell body that rotates to propel the organism through liquid environments

"The peritrichous flagella of Salmonella enable rapid chemotaxis towards nutrient sources."

"capsid"

the protein shell that surrounds and protects the genetic material of a virus

"The icosahedral capsid of the adenovirus consists of 252 protein subunits called capsomeres."

"lytic cycle"

the viral replication pathway in which the virus takes over host cell machinery, replicates, and causes the cell to burst, releasing new virions

"Bacteriophage T4 follows the lytic cycle, producing hundreds of new phage particles before lysing the host bacterium."

"lysogenic cycle"

a viral replication strategy in which the viral genome integrates into the host chromosome and replicates passively with the host cell

"During the lysogenic cycle, phage lambda inserts its DNA into the E. coli chromosome as a prophage."

"viral tropism"

the preference of a virus for specific host cells or tissues, determined by the compatibility of viral surface proteins with host cell receptors

"HIV exhibits viral tropism for CD4+ T cells because its gp120 protein binds specifically to the CD4 receptor."

"reverse transcriptase"

an enzyme used by retroviruses to synthesise double-stranded DNA from an RNA template, reversing the usual flow of genetic information

"HIV relies on reverse transcriptase to convert its RNA genome into DNA that integrates into the host cell nucleus."

"plaque assay"

a method for quantifying the number of infectious virus particles in a sample by counting clear zones of cell death on a cell monolayer

"The plaque assay revealed a viral titre of 1.2 × 10⁸ plaque-forming units per millilitre."

"viral envelope"

the lipid bilayer membrane derived from the host cell that surrounds some viruses, often studded with viral glycoproteins

"Enveloped viruses such as influenza are more susceptible to alcohol-based disinfectants than non-enveloped viruses."

"haemagglutinin"

a glycoprotein on the surface of influenza viruses that binds to sialic acid receptors on host cells and facilitates viral entry

"Annual influenza vaccines are reformulated to match the prevailing haemagglutinin subtypes circulating in the population."

"dimorphic fungus"

a fungus capable of growing in two distinct morphological forms — typically yeast at body temperature and mould in the environment

"Histoplasma capsulatum is a dimorphic fungus that causes pulmonary histoplasmosis in immunocompromised individuals."

"hypha"

a long, branching filamentous structure that constitutes the main mode of vegetative growth in filamentous fungi

"The interwoven network of hyphae forms the mycelium that you see on the surface of mouldy bread."

"sporulation"

the process by which a microorganism forms spores as a mechanism for dispersal, dormancy, or resistance to environmental stress

"Fungal sporulation is triggered by nutrient depletion and is a critical step in airborne transmission of Aspergillus species."

"protozoa"

a diverse group of single-celled eukaryotic microorganisms, many of which are parasitic and cause significant human diseases

"Plasmodium falciparum is a protozoan parasite transmitted by Anopheles mosquitoes that causes severe malaria."

"obligate intracellular parasite"

an organism that can only reproduce and complete its life cycle inside a living host cell

"Toxoplasma gondii is an obligate intracellular parasite that can cause serious neurological disease in immunocompromised patients."

"dermatophyte"

a group of parasitic fungi that infect keratinised tissues such as skin, hair, and nails, causing superficial mycoses known as tinea infections

"Trichophyton rubrum is the most common dermatophyte responsible for tinea pedis, commonly known as athlete's foot."

"trophozoite"

the active, feeding, and reproductive form of a protozoan parasite, as opposed to the dormant cyst stage

"Giardia lamblia trophozoites attach to the intestinal epithelium and cause malabsorption by disrupting villus architecture."

"ergosterol"

the primary sterol found in fungal cell membranes, analogous to cholesterol in human cells, and the key target of many antifungal drugs

"Amphotericin B binds to ergosterol in the fungal cell membrane, forming pores that disrupt osmotic balance."

"minimum inhibitory concentration (MIC)"

the lowest concentration of an antimicrobial agent that inhibits visible bacterial growth in a standardised in vitro test

"A MIC of 0.5 µg/mL for vancomycin indicates that the isolate is susceptible according to current EUCAST breakpoints."

"susceptibility testing"

laboratory procedures that determine whether a pathogen is inhibited by specific antimicrobial agents at clinically achievable concentrations

"Susceptibility testing guided the clinician to switch from empirical broad-spectrum therapy to targeted amoxicillin treatment."

"virulence factor"

a molecule produced by a pathogen that contributes to its ability to cause disease by promoting colonisation, evasion of host defences, or tissue damage

"The Panton-Valentine leukocidin is a virulence factor of Staphylococcus aureus that destroys white blood cells."

"septicaemia"

the presence and multiplication of bacteria or their toxins in the bloodstream, causing systemic illness

"The patient developed septicaemia following an untreated urinary tract infection with Klebsiella pneumoniae."

"nosocomial infection"

an infection acquired during a stay in a healthcare setting, not present at the time of admission

"Healthcare-associated MRSA remains one of the most significant nosocomial infections in surgical wards worldwide."

"culture and sensitivity"

a standard microbiological test in which a clinical specimen is cultured to identify the causative organism and determine its antibiotic susceptibilities

"The wound swab was sent for culture and sensitivity, which confirmed heavy growth of Pseudomonas aeruginosa resistant to ciprofloxacin."

"aseptic technique"

a set of practices used to prevent contamination of sterile items or clinical specimens by pathogenic microorganisms

"Strict aseptic technique during lumbar puncture significantly reduces the risk of introducing infection into the subarachnoid space."

"pathogenicity island"

a distinct genetic element within a bacterial genome that encodes clusters of virulence genes typically acquired by horizontal gene transfer

"The locus of enterocyte effacement is a well-characterised pathogenicity island found in enteropathogenic E. coli strains."

"beta-lactam antibiotic"

a class of broad-spectrum antibiotics containing a beta-lactam ring that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins

"Amoxicillin is a widely prescribed beta-lactam antibiotic effective against many common community-acquired infections."

"antimicrobial resistance (AMR)"

the ability of a microorganism to withstand the effects of an antimicrobial agent to which it was previously sensitive

"The WHO has declared antimicrobial resistance one of the greatest global public health threats of the 21st century."

"plasmid-mediated resistance"

antimicrobial resistance encoded on extrachromosomal plasmid DNA that can be transferred between bacteria through horizontal gene transfer

"Plasmid-mediated resistance to carbapenems has spread rapidly among Enterobacteriaceae in healthcare settings worldwide."

"efflux pump"

a transport protein in the bacterial cell membrane that actively expels antimicrobial agents from the cell, contributing to intrinsic or acquired resistance

"Overexpression of the MexAB-OprM efflux pump is a key mechanism of multidrug resistance in Pseudomonas aeruginosa."

"bactericidal"

describing an antimicrobial agent that kills bacteria directly, as opposed to merely inhibiting their growth

"Fluoroquinolones are bactericidal antibiotics that kill bacteria by inhibiting DNA gyrase and topoisomerase IV."

"bacteriostatic"

describing an antimicrobial agent that inhibits bacterial growth and reproduction without directly killing the bacteria

"Tetracyclines are bacteriostatic agents that work by blocking ribosomal protein synthesis, allowing the immune system to clear the infection."

"multidrug-resistant organism (MDRO)"

a microorganism that is resistant to three or more classes of antibiotics, significantly limiting treatment options

"Carbapenem-resistant Acinetobacter baumannii is an emerging multidrug-resistant organism associated with high mortality in intensive care units."

"post-antibiotic effect (PAE)"

the continued suppression of bacterial growth that persists after antibiotic concentrations fall below the MIC

"Aminoglycosides exhibit a prolonged post-antibiotic effect against gram-negative bacteria, supporting once-daily dosing regimens."

"serial dilution"

the stepwise dilution of a substance in solution, typically used to determine bacterial cell counts or the titre of a virus or antibody

"A serial dilution of the urine sample was plated onto blood agar to quantify the bacterial load as colony-forming units per millilitre."

"streak plate method"

a microbiological technique for isolating pure cultures by progressively diluting a mixed sample across the surface of an agar plate

"The streak plate method successfully isolated individual colonies of the unknown pathogen from the contaminated swab."

"PCR (polymerase chain reaction)"

a molecular technique that amplifies specific DNA sequences exponentially through repeated cycles of denaturation, primer annealing, and extension

"Real-time PCR was used to detect and quantify Mycobacterium tuberculosis DNA directly from sputum samples within four hours."

"MALDI-TOF MS"

matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry; a rapid technique used to identify microorganisms from their unique protein fingerprints

"MALDI-TOF MS identified the blood culture isolate as Candida glabrata within minutes, enabling timely antifungal therapy."

"flow cytometry"

a laser-based technique that measures the physical and chemical characteristics of cells or particles as they flow through a detector, used for rapid enumeration and characterisation of microorganisms

"Flow cytometry allowed researchers to quantify the proportion of antibiotic-tolerant persister cells within the biofilm population."

"selective medium"

a microbiological growth medium that contains agents to inhibit the growth of some organisms while allowing others to grow, facilitating isolation of target species

"MacConkey agar is a selective medium that supports the growth of gram-negative bacteria and differentiates lactose fermenters from non-fermenters."

"Gram stain"

a differential staining technique that classifies bacteria as gram-positive or gram-negative based on properties of their cell walls

"The Gram stain of the sputum showed gram-positive diplococci in pairs, suggesting Streptococcus pneumoniae as the likely causative agent."

"whole genome sequencing (WGS)"

the process of determining the complete DNA sequence of an organism's genome, used in microbiology for outbreak investigation, resistance gene detection, and phylogenetic analysis

"Whole genome sequencing of the outbreak isolates confirmed that all seven cases were linked to a single contaminated source in the food processing plant."