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69 Cards in this Set
- Front
- Back
Names of BACTERIA
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01. Staphylococci
02. Clostridia 03. Aerobic Gram-negative bacilli 04. Bacteroide 05. Streptococci |
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Most imp sterptococcus
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The most important is the β-haemolytic
Streptococcus, which resides in the pharynx of 5–10 per cent of the population |
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Most pathogenic
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In the Lancefield A–G carbohydrate antigens
classification, it is the group A Streptococcus, also called Streptococcus pyogenes, that is the most pathogenic |
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Why strep pyogens most pathogenic?
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t has the
ability to spread, causing cellulitis, and to cause tissue destruction through the release of enzymes such as streptolysin, streptokinase and streptodornase |
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Streptococcus faecalisis Classification
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Streptococcus faecalisis an enterococcus in Lancefield group
D |
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Synergy of Strep fecalis with other organisms
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It is often found in synergy with other organisms, as is the
g-haemolytic Streptococcus and Peptostreptococcus, which is an anaerobe |
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Imp of strep pyogens and strep fecalis in surgery
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Both Streptococcus pyogenes and Streptococcus faecalis may be
involved in wound infection after large bowel surgery |
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a-haemolytic Streptococcus viridans imp in surgery
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a-haemolytic Streptococcus viridans is not associated with wound infections
|
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Medicine to be used
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All the streptococci remain sensitive to
01. penicillin and 02. erythromycin |
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When are cephalosporins used?
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The cephalosporins are a suitable alternative in
patients who are allergic to penicillin. |
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Staphylococci properties
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Staphylococci form clumps and are Gram positive
|
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Imp streptococci in surgery
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Streptococcus pyogenes
Streptococcus faecalis Streptococcus viridans |
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Imp Staphylococci in Surgery
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Staphylococcus aureusi
Staphylococcus epidermidis(previously Staphylococcus albus), also known as coagulase-negative staphylococci (CNS |
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Most imo Staphylococcus
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Staphylococcus aureusis the most important pathogen in this
group |
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Normal occurence
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and is found in the nasopharynx of up to 15 per cent of
the population |
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What it can cause in wounds
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It can cause exogenous suppuration in wounds
(and implanted prostheses) |
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Strain Resistant to ab
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Strains resistant to antibiotics (e.g.
MRSA) can cause epidemics and more severe infection. |
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What should be done in hospital?
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It is
controversial but, if MRSA infection is found in a hospital, all doctors, nurses and patients may need to be swabbed so that carriers can be identified and treated |
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How kept low in Europe?
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In parts of northern Europe,
the prevalence of MRSA infections has been kept at very low levels using ‘search and destroy’ methods, which use these screening techniques and the isolation or treatment of carriers. |
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Patient Access
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Patients found to be positive on screening may be denied access to hospital
|
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MRSA Resistence
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Some MRSAstrains are now also resistant to vancomycin
|
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Local Policies dependence on mam=ngmt
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Local policies on the management of MRSAdepend
on the prevalence of MRSA, the type of hospital or clinical specialty and the availability of facilities |
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Necessary Optionns
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Widespread swabbing,
ward closures, isolation of patients and disinfection of wards all have to be carefully considered and involve all groups of practitioners. They may be expensive but necessary options. |
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Infection types by staph aureus
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Infections are usually suppurative and localised (see above
under Abscess) |
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AB used?
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Most hospital Staphylococcus aureusstrains are
now β-lactamase producers and are resistant to penicillin |
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MRSA Treatment
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but
most strains (MRSA) remain sensitive to flucloxacillin, vancomycin, aminoglycosides, some cephalosporins and fusidic acid (used in osteomyelitis) |
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Available Ab
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There are several novel and innovative
antibiotics becoming available that have high activity against resistant strains |
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Good oral activity
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Some have the advantage of good oral activity
(linezolid |
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Wide Spectrum
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, some have a wide spectrum (tigecycline
|
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Have good act in bacteremia
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have good
activity in bacteraemia (daptomycin |
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Side effects
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And some have side effects involving marrow, hepatic and
renal toxicity |
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Can they be used?
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Their use is justified but needs to be controlled by
tight local policies and guidelines that involve clinical microbiologists |
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Staphylococcus epidermidis Other names
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Staphylococcus epidermidis(previously Staphylococcus albus),
also known as coagulase-negative staphylococci (CNS |
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Imp in surgery
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was
regarded as a commensal but is now recognised as a major threat in prosthetic (vascular and orthopaedic) surgery and in indwelling vascular catheters |
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Resistence
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They can be multiply resistant
(MRCNS) to many antibiotics and represent an important cause of HAI |
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What are clostridial organisms?
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Clostridial organisms are Gram-positive, obligate anaerobes,
which produce resistant spores |
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Clostridium SP
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C. perfringens
C. tetani C. difficile |
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C. perfringens is cause?
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C. perfringens is
the cause of gas gangrene |
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C. Tetani?
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C. tetani causes tetanus after
implantation into tissues or a wound |
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C. Difficile
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C. difficile is the cause of pseudomembranous colitis
|
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Onset of Pseudomemb Colitis
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This is
another HAI, now more common than the incidence of MRSA bacteraemia, which is caused by the overuse of antibiotics |
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Causative drug to PC
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The quinolones, such as ciprofloxacin, seem to be most implicated, but the inappropriate sequential use of several antibiotics puts
patients most at risk, |
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Population Affected?
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particularly in elderly or immunocompromised patients
|
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Symptom
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The key symptom of bloody diarrhoea can
occur in small epidemics through poor hygiene |
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Prognosis
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In its most
severe form, colitis may lead to perforation and the need for emergency colectomy, with an associated high mortality |
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Treatmnt C. difficile
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Treatment involves resuscitation and antibiotic therapy with
metronidazole or vancomycin |
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Investigations
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01. The fibrinous exudate is typical
and differentiates the colitis from other inflammatory diseases; 02. the laboratory recognition of the toxin is an early accurate diagnostic test |
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Aerobic Gram-negative bacilli
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These bacilli are normal inhabitants of the large bowel
|
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Anaerobic gm negative bacilli
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01. E. coli
02. Klebsiella; 03. Proteus. |
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Ecoli Klebsilla Lactose fermentation
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E. coli
and Klebsiellaspp. are lactose fermenting |
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Proteus lactose fermentation
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Proteusis non-lactose
fermenting |
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Imp in Surgery
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Most organisms in this group act in synergy with
Bacteroides to cause SSIs after bowel operations (in particular, appendicitis, diverticulitis and peritonitis). |
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E coli imp
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E. coli is a major
cause of the HAI of urinary tract infection |
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UTIs other org
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although most aerobic Gram-negative bacilli (AGNB) may be involved
|
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Procedure?
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particularly in relation to urinary catheterisation
|
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ESBL development Extended spectrum B lactamase
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There is increasing
concern about the development of ESBLs in many of this group of bacteria |
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Resistence
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which confer resistance to many antibiotics, particularly cephalosporins
|
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Pseudomonas imp in surgical procedures
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Pseudomonas spp. tend to colonise burns and tracheostomy
wounds, as well as the urinary tract. |
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Eradication in hospital easy?
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Once Pseudomonashas colonised wards and intensive care units, it may be difficult to eradicate.
|
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What should be done in outbreaks?
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Surveillance of cross-infection is important in outbreaks.
|
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Resistence?
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Hospital strains become resistant to β-lactamase as resistance
can be transferred by plasmids |
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When Ab therapy to be given?
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Wound infections need antibiotic therapy only when there is progressive or spreading infection with systemic signs.
|
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Ab to be used
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01. The aminoglycosides are effective, but
some cephalosporins and penicillin may not be. 02. Carbazepam |
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Carbazepams
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Many of the
carbapenems (e.g. meropenem) are useful in severe infections, |
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Quinolones
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whereas the quinolones have been made ineffective through
their overuse and the development of ESBLs. |
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Ab not to be used
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Cephalosporins
Penicillins Quinolones |
|
Bacteroides?
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Bacteroides
Bacteroidesare non-spore-bearing, strict anaerobes that colonise the large bowel, vagina and oropharynx. |
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Imp in sugery
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Bacteroides fragilisis
the principal organism that acts in synergy with AGNB to cause SSIs, including intra-abdominal abscesses, after colorectal or gynaecological surgery. |
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Ab to used
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They are sensitive to the
imidazoles (e.g. metronidazole) and some cephalosporins (e.g. cefotaxime). |