Bactriology Lecture 3 Wk7 Flashcards

Question

Actinobacteria/Firmicutes

Answer 1

Firmicutes : lactic acid bacteria Lactobacillus delbruekii

Answer 2

Glucose —> 2pyruvate —> 2lactate Glycolysis Lactate fermentation

Answer 3

Firmicutes : endoscope forming bacteria (clostridium, Bacillus)

Answer 4

Exosporium nap (BcIA) Exosporium basal layer

Answer 5

|| aureus = purple circles in clumps Staphyloxanthin = beige rounds blobs

Answer 6

1. Alpha hemolysis 2. Bete hemolysis 3. Gamma hemolysis

Answer 7

Incomplete / partial hemolysis, green hemolysis Caused by hydrogen peroxide produced by bacteria Oxidising hemoglobin to green methemoglobin

Answer 8

Complete hemolysis Caused by enzyme (streptomycin or exotoxin) Produced by bacteria

Answer 9

Non-haemolytic

Answer 10

6 VRE phenotype

Answer 11

Mycoplasma : ~0.6 Mb Bifidobacteria : ~2 Mb staphylococci : 2.8-3 Mb Escherichia : 4.5 - 5 Mb Actinomycetes : 8-9 Mb Yesterday : ~14 Mb

Answer 12

Mycobacterium tuberculosis Complex cell envelope of Mycobacterium

Answer 13

-bovis -israelii

Answer 14

Free spore - germination + growth of substrate mycelium - development of aerial mycelium - growth of an apical aerial hypha - coiling of apical hyphal cell - sporulation-specific septum formation - completion of septation- maturation of spores - dispersal of spores

Answer 15

Spore germination Vegetative growth Substrate mycelium Antibiotic production Formation of reproductive aerial hyphae Aerial hypha Chromosome segregation and separation Spore mutation Spore dispersal

Answer 16

8,667,507bp

Answer 17

Streptococcus pneumoniae, Mycobacterium tuberculosis

Answer 18

Camphylobacter jejuni, salmonella species, Shigella species, Escherichia coli 0157:H7, Helicobacter pylori

Answer 19

Enterobacter species, Pseudomonas aeruginosa, Enterococcus species, Staphylococcus species.

Answer 20

Lower respiratory tract Trachea Primary bronchi Lungs Pneumonia Tuberculosis

Answer 21

Lung inflammation Streptococcus pneumoniae Symp- cough, chest pain, fever, diff breathing Vaccination, various antibiotics

Answer 22

Normal inhabitant of human respiratory tract, causes pneumonia Common cause of bacterial meningitis, ear infections Gram-positive 0.5-1.25 µm in diameter doesn’t form spores, non-motile, alpha hemolytic when cultured on blood agar Encapsulated coccoid bacteria Polysaccharide capsule (virulence factor) 1 cirlcular chromosome = 2 base pairs, GC content of ~40%

Answer 23

1. Commonly used antibiotics : β-lactams (penicillin, amoxicillin, ampicillin) : Cephalosporins (cefotaxime, ceftriaxone) : Macrolides (erythromycin, azithromycin) : Fluroquinolones : Glycopeptides (vancomycin) 2. Antibiotic resistance : Penicillin and Cephalosporins – resistance is common, mediated by altered PBP, transmissible to other pneumococcal strains : Macrolides – efflux pump or ribosomal mutations : Quinolones – efflux pump or DNA gyrase mutations : Vancomycin – no resistance yet

Answer 24

1. Pneumococcal polysaccharide vaccine (PPV or PPSV) : contains long chains of polysaccharide (sugar) molecules that make up the surface capsule of the bacteria : a pure polysaccharide vaccine induces only short-term immunity and doesn’t work as well in children younger than 2 years : PPSV (Pnuemovax 23 = PPV-23 is known as the latest version) is the first vaccine derived from a capsular polysaccharide : widely used in high-risk adults 2. Pneumococcal conjugate vaccine (PCV) : purified capsular polysaccharides from the bacteria that are "conjugated" (or joined) to a harmless variety of diphtheria toxin : produces an immune response in infants and antibody booster response to multiple doses of vaccine : the British immunisation schedule for infants, with the first dose given at two months old, and is now licensed to protect against invasive disease caused by Streptococcus pneumoniae in adults aged 50 years and older : PCV7, PCV13

Answer 25

Attacks lungs Lethal infectious disease caused by mycobacteria Spread through air 1/3 infected 1.3 M deaths 2022 Treatment long course of multiple antibiotics Chronic cough, blood-tinged sputum, fever, night sweats, weight loss

Answer 26

-rod-shaped, non-motile, related to actinomycetes -Acid-fast gram-positive or gram-resistant bacteria - waxy coating on cell surface (mycolic acid) = impervious to gram staining -slow growth: divides 15-20 hours -strain variation: significant phenotypic differences between clinical isolates -circular chromosome, GC content 65%: H37Rv strain (4 mega base with 3959 genes) -multi drug-resistant TB (MDR-TB) extensively drug-resistant TB (XDR-TB) major problem

Answer 27

Isoniazid Rifampin Pyrazinamide Ethambutol Isoniazid Rifampin

Answer 28

Food borne illness: gastroenteritis, typhoid fever, paratyphoid fever -two species, salmonella enterica + salmonella bongori -zoonotic -gram-negative, rod-shaped, non-spore-forming, anaerobic, motile with flagella -0.7-1.5 µm in diameter, 2 - 5 µm in length- chemoorganotrophes : obtaining energy from oxidation and reduction reactions using organic sources - produce hydrogen sulfide

Answer 29

Salmonella enterica, serotype Typhi -infects humans only, causes enteric bacterial infection, typhoid fever -symptoms High fever, sweating, diarrhoea, inflammation of stomach /+ intestines. Enlargement of liver + spleen “rose spotted” skin rash on chest + abdomen - 2 million cases, 500,000 deaths -treatment Drug resistance (MDR) -prevention Hygienic life style Vaccines- the live, oral vaccine (Ty21a) + injectable tyhpoid polysaccharide vaccine - 1st genome sequence S. typhi CT18 (MDR) strain 4.8 Mb circular chromosome, 2 plasmids pHCM1 (MRC) + pHCM2

Answer 30

- Gram-negative, rod shaped bacteria - “O" refers to the cell envelope (LPS) antigen number, "H" refers to the flagella antigen - Enterohemorrhagic E. coli (EHEC) - Shiga-like toxin producing E. coli (STEC) - symptoms of E. coli 0157:H7 infection : a low fever, nausea, vomiting, stomach cramps, and bloody diarrhoea - fatal condition : hemolytic uremic syndrome (HUS) - treatment : non-specific supportive therapy, including hydration, is important : no evidence that treatment with antibiotics is helpful, and taking antibiotics may increase the risk of HUS : antidiarrheal agents such as Imodium should be avoided as it may prolong the duration of the infection

Answer 31

Causes gastritis, gastric ulcers + stomach cancer Helix-shaped, motile, gram-negative, 3 3 µm long with 0.5 µm diameter - genome : 1.6 Mb with 1590 coding genes, 29% of genome is involved in the pathogenesis - virulence of Helicobacter pylori : measured by the ability to produce cotoxin-associated protein (CagA) and active vacuolating cytotoxin (VacA) : Cag pathogenicity island : about 40 Kb long, responsible for pathogenesis, usually absent from H. pylori strains isolated from humans : other important virulent factors - surface-exposed lipopolysaccharide - iron-scavenging system - urease - motility for colonization - type IV secretion system

Answer 32

- therapy one week ‘triple therapy’ 1 proton pump inhibitor 2 antibiotics - clarithromycin + amoxicillin, || + metronidazole - additional rounds of antibiotic therapy after failure ^ “Quadruple therapy” + bismuth colloid drug Treatment of clarithromycin-resistant H.pylori vaccine levofloxacin -prevention Vaccination Probiotic diet

Answer 33

50% mortality, 4th commonly-isolated nosocomial pathogen -gram-negative, rod-shaped, motile + long monoflagellum -Single cell size 1-5 µm long and 0.5-1.0 µm wide - P. aeruginosa often identified by the production of pyocyanin and fluorescein and ability to grow at 42°C. - pollution control - break down aromatic hydrocarbons - intrinsic resistance to antibiotics P. aeruginosa genome (PA01 strain) : circular form, 6.2 Mb size with ~65% GC content

Answer 34

reversible attachment irreversible attachment microcolony formation development of 3-dimensional structure Dispersal

Answer 35

Swarming Swimming Twitching

Answer 36

N-acyl homoserine lactone

Answer 37

-low permeability to antibiotics = resistant - biofilm -s ome antibiotics have shown to be active against P. aeruginosa : aminoglycosides (gentamicin, amikacin, tobramycin) : quinolones (ciprofloxacin, levofloxacin, moxifloxacin) : carbapenems (meropenem, imipenem, doripenem) : polymyxins (polymyxinB, colistin) : monobactams (aztreonam) : cephalosporines (ceftazidime, cefepime, cefoperazone, cefpirome) : antipseudomonal penicillins (ureidopenicillins, carboxypenicillins) - phage therapy combined with antibiotics

Answer 38

- nosocomial infections - UTI -genus of lactic acid bacteria -tolerant of wide range of environmental conditions 10-45 °C), pH (4.5-10) and high sodium chloride concentrations -common in intestines : Enterococcus faecalis (90-95%), Enterococcus faecium (5-10%) - pathogenicity : cytolysin, a toxin causes rupture of a variety of target membranes, including bacterial cells, erythrocytes, and other mammalian cells - vancomycin resistant enterococcus (VRE)

Answer 39

-1st VRE genome sequence from VanB-type Enterococcus faecalis V583 strain : 1 circular chromosome with 3.2 Mb long (3337 genes), 3 plasmids : more than 25% of total genes are exogenously acquired - 7 integrated phage regions - 38 insertion elements - conjugative and composite transposons - pathogenicity island - vancomycin resistance genes encoded within a previously unknown mobile element in genomic DNA (similar to Tn1549 in other VanB-type E. faecalis) - some other VanA-type VRE carry van resistance allele in plasmid : pIP816 in E. faecium BM4147 - 11 kb long, 9 encoding vancomycin resistance cluster - orf1, orf2, vanR, vanS, vanHAX, vanY, vanZ

Answer 40

Greek = bunch of grapes + granule -gram-positive (thicker peptidoglycan cell wall)+ immotile - 40 species -yellow colonies - S. aureus White colonies - S. epidermidis -first genome sequence S. aureus strain NCTC8325 : circular genomic DNA with 2.8 Mb long with 2900 genes. : 33% GC content

Answer 41

Most common -nosocomial infections, post surgical wound infections -successsful pathogen - immunodeficiency-evasive strategies -emergence of MRSA (Methicillin-Resistant S. aureus) : resistant to almost all clinically available β-lactam antibiotics including penicilins and cephalosporins : vancomycin became the primary antibiotic used to combat MRSA : due to mecA encodes a modified PBP

Answer 42

Drug resistance in six pathogens 929,000 (direct) + 3.57 million (associated) Escherichia coli Staphylococcus aureus Klebsiella pneumoniae Streptococcus pneumoniae Acinetobacter baumannii Pseudomonas aeruginosa MRSA itself > 100,000

Answer 43

Resistant to vancomycin + teicoplanin -acquired VanA type vancomycin resistance genes from VanA-type VRE via horizontal gene - transfer mediated by transposon -antibiotics Trimethoprim/sulfamethoxazole, quinuprisitin/dalfopristin, tigecycline, linezolid and daptomycin - novel antibiotics against VRSA is urgently required