PowerPoint Presentation

Antibiotics part IIDr. Nabila HassanTropical medicine MDZagazig university

Medical important bacteriaLack cell wallmycoplasmaureaoplasma

flexiable spirochetesBorrelialeptospirallisTreponema

rigid cell wallfilamentousactinomycesmycobacterinocardiasimple unicellular

obligate intra cellularChylamadiaCoxillaEhrlichiaRickettsiafree living gram positivegram negative

Gram positiveStaphStreptenterococcipeptostreptococcus

BacillibacillusClostradiumcoyrneubacteriumEriseplothirixLactobacillusListeriapropnionibacterium

cocci

Gram negative organismscocciNiesseriamorexalleacinobacterBacillinon enteric bacilli

HaemophilusBordetellaLegionella BrucellaFrancisella tularensisPasteurellaYersinia PestisBartonella

pseudmonsenteric rodsenterobacilliEcherechiafuseobacteriumhelicobacterkleibacilliprevotellaproteusProvendeicaPseudomonossallemonellaserratiashigelliaVibrioYersinia

This difference is relative, as bacteriostatic drugs are often bactericidal at high concentrations and in the presence of host defence mechanisms.

In clinical practice, the distinction is seldom important unless the bodys defence mechanisms are depressed.BacteriostaticBactericidalErythromycinTetracyclinesChloramphenicolSulphonamidesTrimethoprimPenicillinsCephalosporinsAminoglycosidesCo-trimoxazole

Antibacterial agentMechanism of actionPenicillinsCephalosporinsMonobactamsVancomycinPolypeptide AntibioticsInhibition of cell wall synthesis

Cell wall and cell membraneQuinolonesInhibition of DNA gyraseRifampicinInhibition of RNA polymeraseAminoglycosidesTetracyclinesErythromycinChloramphenicolInhibition of protein synthesis TrimethoprimSulphonamidesInhibition of folic acid metabolism

New Classes of AntibioticsFour new classes of antibiotics have been brought into clinical use in the late 2000s and early 2010s:

Cyclic lipopeptides (such as daptomycin), Glycylcyclines (such as tigecycline), Oxazolidinones (such as linezolid),Lipiarmycins (such as fidaxomicin)

CASE STUDY

A45-year-old woman is undergoing chemotherapy for breast cancer. She presents 10 days after her last chemotherapy with fever (temperature >38.5C),

but no other symptoms except a sore throat and mouth. On examination, she looks well, there is oral mucositis, ears are normal, lungs are clear, and the central line site is clean.

The CXR, urinalysis, and biochemistry are normal. Her WBC is 800/mL and the absolute neutrophil count is low (90 mL/min and 30 mL/min: Dose adjustment not necessaryCrCl 15-30 mL/min: Decrease dose by 50%CrCl