Microbiology - MCQ Practice Questions

A patient presents with severe respiratory infection. Gram-staining reveals gram-negative rods that are oxidase-positive and motile. Which organism is most likely responsible?

Which of the following bacterial structures is responsible for horizontal gene transfer through direct cell-to-cell contact?

A laboratory identifies a virus with positive-sense, single-stranded RNA genome. Which process can this virus directly initiate without viral RNA-dependent RNA polymerase?

Which bacterial genus produces endospores as a survival mechanism under nutrient-depleted conditions?

A researcher observes that a bacterial strain previously sensitive to penicillin now survives treatment. Analysis shows increased production of beta-lactamase. This exemplifies which mechanism of antibiotic resistance?

In a clinical sample, Mycobacterium tuberculosis appears as acid-fast positive. This property is due to which cell wall component?

Which virus possesses a segmented genome and is responsible for causing influenza pandemics?

A viral infection shows symptoms of hemorrhagic fever with high mortality. Laboratory tests reveal negative-sense RNA and a helical capsid. Which family of viruses is most likely?

Which bacterial flagellar protein is the primary target of monoclonal antibodies used in serological identification?

A gram-positive coccus forms grape-like clusters and produces alpha-toxin. Which pathogen is being described?

In viral replication, which process involves the insertion of viral DNA into host chromosomes, as seen in retroviruses?

A bacterium isolated from contaminated water shows resistance to multiple antibiotics and possesses a plasmid. Which method would effectively identify if the plasmid carries resistance genes?

Which viral protein is responsible for recognizing and binding to host cell receptors during viral attachment?

A patient with chronic Pseudomonas aeruginosa lung infection shows biofilm formation. Which virulence factor primarily enables this?

Which of the following accurately describes the replication cycle of a negative-sense RNA virus?

A bacterial colony on blood agar shows beta-hemolysis and is catalase-positive, coagulase-positive. Which species is confirmed?

In SARS-CoV-2, which structural protein is responsible for membrane fusion and is the primary target of neutralizing antibodies?

Which bacterial genus requires X factor (hemin) and V factor (NAD) for growth, making it fastidious?

A virus exhibits tropism exclusively for liver hepatocytes. Which viral component determines this tissue-specific infectivity?

In 2024, which antimicrobial stewardship approach has been emphasized to combat carbapenem-resistant Enterobacteriaceae (CRE)?