1Dolly [email protected] Medical Tourism Agency Health Options Worldwide (HOW) Discusses India's Resistant Medical Travel "Super Bug“NDM-1 (New Delhi metallo-beta-lactamase bacteria) was found in British patients returning from Bangladesh, India, and Pakistan after medical treatment The NDM1 is also being carried over bytreatment. The NDM-1,, is also being carried over by patients in the United States and South Asia, who also have received surgical care in India. "Scientists say it is highly resistant to antibiotics and is nearly impossible to treat," said David Goldstein, President of Health Options WorldwidePenicillins (PCN or PEN)CephalosporinsClavulanateCarbapenemsBacterial cell wallCarbapenemsVancomycincell wallProteoglycan (PG) (15-50 nm thick)Plasma membraneGram positive bacterial cell wallPG (2 nm thick)Plasma membraneLipopolysacharides (LPS) periplasmGram negative bacterial cell wall LPS: lipid A + core polysaccharides, O antigen Gram negative bacterial cell wall PeptidoglycanMN acetylmuramic acid (NAMA) GN acetylglucosamine (NAG)GN acetylglucosamine (NAG)Penta peptide Glycine2M G M G M GM G M G M GMM G M G M GBiosynthesis of Peptidoglycan30 enzymes1) Precursor formation: Cytoplasm2) Binding with phospho-C55 lipid carrier to form long polymer: Cell membraneThree stages: to form long polymer: Cell membrane 3) Cross-linking in cell wallMUDPUDPMUMPGUDPUDPCYTOsynthetaseL-alanineD-alanineracemaseP-C55 lipidP-P-C55MP-P-C55MGMEMBWALLP-P-C55MGGMM G M G M GP-P-C55 lipidtransglycolasePtranspeptidaseGPenicillin: -Lactam antibioticsDrug of choice for a large number of diseasesDiscovered by Alexander Flemming 1928. Produced by penicilliumProduced by penicilliumCCH COOHCH3CH3SCHNCHC=ONHCR=O-lactum ring Thiazolidine ringPenicillinase/-lactamase6APA6-aminopenicillanic acidamidaseR decides:stability for stomach acidsAntibacterial activityPenicillin subtyperesistance to -lactamasepi.e. penicillin nucleus (requiredfor biological activities)Classification Spectrum Natural Penicillins Gram (+) cocci, hydrolyzed by penicillinase so ineffective against most strains of S. aureus-lacatamse resistant PenicillinLess active agnst bacteria sensitive to Penicillin G First choice for S aureus and S epidermidisAminopenicillins/ Gram (-) e.g Hemophillus influenzae, OCH2-CH2-OCH3 OCH3 modern spectrum E.Coli, Neissaria sp.Administered with -lactamse inhibitor such as clavanate to prevent hydrolysisCarboxypenicillin Gram (-) e.g. pseudomonas sp, enterobacter sp. Inferior to ampicillinagainst Gram + cocciUreidopenicillins/extended penicillinPseudomonas sp, 10 times more effective than carboxypenicillinCH2-R1NH2CH-COOR3Mechanism of InhibitionAll -Lactam antibiotics binds penicillin binding proteins (PBP) belong to acyl serine transferasesPBPs: required for final stages of cell wall synthesisi.e. peptidoglycan (bind covalently)-lactum antibodiesCell lysisAcylation of PBPsInhibition of PBPs Structural irregularitieslactum antibodiesTransglycolase (TG) (insensitive to penicilin) formation of linear glycan strands SerNCTG TPPBP domain structureTranspeptidase (TP) (sensitive to penicillin)cross-link the peptide subunits) serine residue (required for covalent bond formation) at the active site is conserved in all members of the PBP family . M G M G M GM G M G M GMM G M G M Ghigh-molecular-weight (HMW) PBPs include transpeptidaselow-molecular-weight (LMW) PBPsmay maintain shape of bacteriaypPBP’s (40kD-91kD):Number of PBPs varies within bacterial strain. i.e. S aureus has 4 PBPs whereas E coli has 7ProteinApparent molecular weightBinding of penicillin( % total )Molecules/cell1910008.12301910008.12302 66000 0.7 203 60000 1.9 504 49000 4.0 1105 42000 64.7 18006 40000 20.6 570Affinity of PBPs to antibiotics is variablePenicillinLytic PBP1 (leads to deathNon-lytic (PBP2/3) (affect holin-like proteins in (leads to death of bacterial cell) bacterial cell memb which alter membrane potential)4Mechanisms of Penicilin ResistanceA. Elaboration of normal PBPs B. Inability of agent to penetrate to site of actionC. Increased expression of efflux pumps i.e E. coliD. Production of -lactamaseA. Elaboration of PBPs a) decreased affinity for -lactamsa2 by transposans from unknown orga1. formed by homologous recombination between PBPs of different bacterial speciesa2. by transposans from unknown orgb) structural differences in PBPsB. Inability of agent to penetrate to site of actionb1. Gram (-) bact outer layer of LPSSmall hydrophilic antibiotics can pass through channels porinsi.e. amoxicillin, ampicillin>Penicillin GPaeruginosaresistant to most antibiotics lacksP aeruginosaresistant to most antibiotics lacks porinsC. Increased expression of efflux pumps i.e E. coliMajor facilitator superfamily (MFS)Adenosine triphosphate binding cassette (ABC)Small multidrug resistance (SMR)Resistance nodulation cell division (RND)Gram (-) Multidrug and toxic compound extrusion (MATE)D. Production of -lactamased1. -lactamases class A-D:Class A, C and D works by hydrolyzing serine ester Class B (Zn-dependent) Class Aextended spectrumlactamase; degradeHydrolyse  lactam ring of penicillin's Class Aextended spectrum -lactamase; degrade penicillin, some cephalosporin's and carbapenemsClass B destroy all -lactums except aztreonamClass C cephalosporin'sClass D cloxacillin5Gram (+),  lactamase is secreted extracellularly in large amountsGram (-),  lactamase is located in the periplasmic space, small amounts. d2. Site of liberationPrimary mechanism of acquired resistance!d3. Other factors: surviving bacterial cell, biofilms produce bacteria in prostheticsDistributionwidely distributed; concentration varies in diff tissues. therapeutic concentrations is achieved readily in joint fluid, pleural fluid, pericardial fluid, and bile Do not penetrate phagocytic cells, very low conc in prostatic fluids brain tissue and intracular fluidGeneral features of the Penicillinsprostatic fluids, brain tissue, and intracular fluid<1% in CSF when meninges are normal; ~5% when inflamed meningisActive transport process pumps penicillin's from CSF to the bloodstream. This mechanism is blocked by ProbenecidExcretionEliminated by glomerular filtration. Higher urine concentrations. CCH COOHCH3CH3SCHNCHC=ONHCR=OBAamidaseCHNCHC=OOH HPenicilloic acidNH2+CHR=OCH6-APAPenicillanaseamidaseNatural PenicillinPenicillin GPenicillin VPen V is superior to Pen G because of