36 Matching Annotations
  1. Jun 2017
    1. The Lassa virus genome contains two single-stranded RNA segments, one large one that is responsible for encoding the viral polymerase and zinc binding proteins and a smaller one that encodes the structural proteins.

      Both the Lassa virus and the Respiratory syncytial virus contain a negative sense genome. However, the Lassa virus genome has two RNA strands, while the RSV genome has only one.

    1. RSV is a medium-sized (120-200nm) enveloped virus with a negative-sense, single-stranded RNA genome

      Both the Lassa virus and the Respiratory syncytial virus contain a negative sense genome. However, the Lassa virus genome has two RNA strands, while the RSV genome has only one.

  2. May 2017
  3. onlinelibrary.wiley.com onlinelibrary.wiley.com
    1. S. pneumoniae, H. influenzae, M. catarrhalis, group A beta-hemolytic streptococci and S. aureus (12, 18, 21–24, 63) (Table 1). The introduction of vaccination of children with the 7-valent pneumococcal vaccine in 2000 in the USA brought about a decline in the incidence of S. pneumoniae and an increase in H. influenzae in sinusitis

      Common bacterial causes

    1. Resistance to beta-lactam antibiotics has become a particular problem in recent decades, as strains of bacteria that produce extended-spectrum beta-lactamases have become more common.[55] These beta-lactamase enzymes make many, if not all, of the penicillins and cephalosporins ineffective as therapy

      Antibiotic resistence

    2. In stool samples, microscopy will show gram-negative rods, with no particular cell arrangement. Then, either MacConkey agar or EMB agar (or both) are inoculated with the stool. On MacConkey agar, deep red colonies are produced, as the organism is lactose-positive, and fermentation of this sugar will cause the medium's pH to drop, leading to darkening of the medium. Growth on EMB agar produces black colonies with a greenish-black metallic sheen. This is diagnostic of E. coli. The organism is also lysine positive, and grows on TSI slant with a (A/A/g+/H2S-) profile. Also, IMViC is {+ + – -} for E. coli; as it is indole-positive (red ring) and methyl red-positive (bright red), but VP-negative (no change-colourless) and citrate-negative (no change-green colour).

      Lab tests

    1. E. coli O157:H7 infection often causes severe, acute hemorrhagic diarrhea (although nonhemorrhagic diarrhea is also possible) and abdominal cramps. Usually little or no fever is present, and the illness resolves in five to 10 days. It can also be asymptomatic.

      Symptoms

    1. The multiple resistance pattern most often observed was that of streptomycin, sulfisoxazole, and tetracycline

      Common antibiotic resistance in group of 3

    1. Identification[edit] Test Results Gram Stain - Oxidase + Indole Production - Methyl Red - Voges-Proskaeur - Citrate + Hydrogen Sulfide Production - Urea Hydrolysis + Phenylalanine Deaminase - Lysine Decarboxylase - Motility + Gelatin Hydrolysis + Acid from lactose - acid from glucose - acid from maltose - acid from mannitol + acid from sucrose - nitrate reduction + DNAse - Lipase + Pigment + (bluish green pigmentation) Catalase +

      All important lab tests

    1. In order to establish infection, the bacteria need to escape the host immune response, and in streptococci, a varied arsenal of bacterial strategies have been described. The M-protein aids in immune evasion by inhibiting phagocytosis and inactivating the complement system.[1] Furthermore, Streptococcus dysgalactiae possesses Protein G, a virulence factor binding circulating immunoglobulins, and thus interfering with the host antibody response.[49] DrsG, a virulence protein abrogating the effect of antimicrobial peptides secreted by human immune cells, is also harboured by a subset of SDSE-strains.[50][51]

      Virulence factors

    1. All isolates were susceptible to penicillin and levofloxacin, 6 (26.1%) showed resistance or reduced susceptibility to erythromycin [1 mef(A), 3 erm(TR), 1 mef(A)+erm(TR) and 1 erm(TR)+erm(B)] and 7 (30.4%) were resistant or exhibited reduced susceptibility to tetracycline [2 tet(M), 5 tet(M)+tet(O)]. The prevalence in Argentina was of at least 23 invasive infections by SDSE. A wide genetic diversity was observed. All isolates carried speJ and ssa genes. Similarly to other studies, macrolide resistance (26.1%) was mainly associated to the MLSB phenotype.

      Antibiotic resistance info

  4. Apr 2017
    1. For presumptive identification of S. pyogenes, cultures should be tested for bacitracin susceptibility and PYR activity (as described below). A definitive diagnosis should include a positive Lancefield group A antigen test. Negative results can be confirmed after a total culture time of 48 hours.

      IMPORTANT!!! Include under Question 12 (Other tests):

      1. Increased bacitracin sensitivity (bacitracin = antibiotic) 2.PYR activity (tests for enzyme that produces red color under test conditions and is specific to S. pyogenes)
      2. Lancefield group A antigen test (Definitive diagnosis)
    1. The ability of bacterial species to hydrolyze the compound hippurate was classically tested using ferric chloride indicator to detect benzoic acid, the first byproduct in the hippurate hydrolysis pathway. However, a 2½ hour rapid method as opposed to the 48 hour classical method for detecting hippurate hydrolysis has since been developed. The rapid test employs ninhydrin as the indicator, which detects glycine, the second byproduct of hippurate hydrolysis. The rapid hippurate hydrolysis test has been shown to be as specific and as sensitive as the classical method that detects the benzoic acid byproduct. (4,5,8,9)

      Hippurate test

    1. Superantigens are potent immunostimulators that cause clonal proliferation of T cells and watershed production of pro-inflammatory cytokines that mediate shock and organ failure.

      Superantigens cause STSS by inducing T-cell proliferation and production of proinflammatory cytokines.