scholarly journals PATTERNS OF BACTERIAL RESISTANCE TO PENICILLIN, AUREOMYCIN, AND STREPTOMYCIN 1

1949 ◽  
Vol 28 (5 Pt 1) ◽  
pp. 891-893 ◽  
Author(s):  
M. Demerec
Keyword(s):  
Bacterial Resistance ◽  
Resistance To Penicillin

scholarly journals On the origin of bacterial resistance to penicillin: comparison of a beta-lactamase and a penicillin target

Science ◽  
1986 ◽  
Vol 231 (4744) ◽  
pp. 1429-1431 ◽  
Author(s):  
J. Kelly ◽  
O Dideberg ◽  
P Charlier ◽  
J. Wery ◽  
M Libert ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Beta Lactamase ◽  
Resistance To Penicillin

scholarly journals CUTANEOUS BACTERIAL INFECTIONS

2006 ◽  
Vol 13 (04) ◽  
pp. 591-595
Author(s):  
AJMAL RASHID ◽  
MOHAMMAD A. NAEEM
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Systemic Disease ◽  
Skin Lesions ◽  
Military Hospital ◽  
Tissue Fluid ◽  
Pattern Design ◽  
Resistance To Penicillin ◽  
Antibacterial Susceptibility

Objective: To find out causative pathogens and their frequency in study group in common cutaneousbacterial infection and determine antibacterial susceptibility pattern. Design: Samples were collected either by swabsfrom skin lesions or where required aspiration of tissue fluid followed by examination in the laboratory for identificationof organisms through culture on appropriate media and antimicrobial susceptibility testing. Setting: Department ofDermatology Military Hospital Rawalpindi. Subjects: Hundred patients irrespective of age and sex who had notreceived antibiotic in last 72 hours, with a clinical diagnosis of any common cutaneous bacterial infection were selectedirrespective of any coexisting cutaneous or systemic disease. Results: The data was compiled and statistical analysiswas done by using SPSS version 10. Isolated colonies of Staphylococcus aureus were found in 52% of the cases whileStreptococcus pyogenes was found as a pure growth in 18% of the cases. Mixed cultures of both these organisms werefound in 30% of the cases. Staphylococcus aureus resistance to Penicillin (97.5%), Erythromycin (37.8%),Cotrimoxazole (31.7%), Cephradine (30.4%) and Tetracycline (34.1%). Resistance against Cloxacillin (3.6%) andGentamicin (2.4%) was much less. Among 82 isolated Staphylococcus aureus three isolated (3.6%) were found to beMRSA (Methicillin Resistant Staphylococcus Aureus). Streptococcus pyogenes although found completely sensitiveto penicillins, showed resistance to Tetracycline (39.5%), Cotrimoxazole (31.2%) Erythromycin (27%) and Gentamicin(10.5%) Vancomycin sensitivity was shown by 100% of isolates. Conclusion: The comparison of this study withprevious studies indicates that problem of bacterial resistance amongst common cutaneous pathogens is increasing.The situation calls for creating awareness regarding dangers of indiscriminate use of antibiotics.

scholarly journals β-Lactam synthetase: A new biosynthetic enzyme

1998 ◽  
Vol 95 (16) ◽  
pp. 9082-9086 ◽  
Author(s):  
Brian O. Bachmann ◽  
Rongfeng Li ◽  
Craig A. Townsend
Keyword(s):  
Clavulanic Acid ◽  
Bacterial Resistance ◽  
Streptomyces Clavuligerus ◽  
Acid Synthesis ◽  
Oxidative Cyclization ◽  
Sequence Comparisons ◽  
Insertional Inactivation ◽  
Lactam Ring ◽  
Resistance To Penicillin ◽  
Primary Amino

The principal cause of bacterial resistance to penicillin and other β-lactam antibiotics is the acquisition of plasmid-encoded β-lactamases, enzymes that catalyze hydrolysis of the β-lactam bond and render these antibiotics inactive. Clavulanic acid is a potent inhibitor of β-lactamases and has proven clinically effective in combating resistant infections. Although clavulanic acid and penicillin share marked structural similarities, the biosyntheses of their bicyclic nuclei are wholly dissimilar. In contrast to the efficient iron-mediated oxidative cyclization of a tripeptide to isopenicillin N, the critical β-lactam ring of clavulanic acid is demonstrated to form by intramolecular closure catalyzed by a new type of ATP/Mg2+-dependent enzyme, a β-lactam synthetase (β-LS). Insertional inactivation of its encoding gene in wild-type Streptomyces clavuligerus resulted in complete loss of clavulanic acid production and the accumulation of N2-(carboxyethyl)-l-arginine (CEA). Chemical complementation of this blocked mutant with authentic deoxyguanidinoproclavaminic acid (DGPC), the expected product of the β-LS, restored clavulanic acid synthesis. Finally, overexpression of this gene gave the β-LS, which was shown to mediate the conversion of CEA to DGPC in the presence of ATP/Mg2+. Primary amino acid sequence comparisons suggest that this mode of β-lactam formation could be more widely spread in nature and mechanistically related to asparagine synthesis.

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