Penicillin

About: Penicillin is a research topic. Over the lifetime, 17916 publications have been published within this topic receiving 368480 citations. The topic is also known as: penicillin antibiotic & PCN.

Iodometric Detection of Haemophilus influenzae Beta-Lactamase: Rapid Presumptive Test for Ampicillin Resistance

Abstract: Strains of Haemophilus influenzae type b sporadically isolated from clinical specimens are ampicillin resistant due to production of a beta-lactamase. This enzyme which inactivates ampicillin and penicillin G is not produced by ampicillin-susceptible strains. Various characteristics of beta-lactamase production and ampicillin resistance of three H. influenzae type b isolates were investigated. A sensitive iodometric test was employed to detect beta-lactamase; positive results were obtained in 5 min with 10(9) bacteria taken from cultures on a nutritionally adequate agar medium. This simple chemical test will enable the hospital laboratory to obtain presumptive evidence of ampicillin resistance on the same day that H. influenzae is isolated.

T cell recognition of penicillin G: Structural features determining antigenic specificity

Abstract: Penicillin G (Pen G) and other beta-lactam antibiotics frequently induce allergic reactions constituting typical examples of human immune responses to haptens. In fact, penicillins represent a unique set of haptens with outstanding structural variability on the basis of an identical protein-reactive beta-lactam containing backbone. Although both cellular and humoral responses are involved in drug-induced allergies, little is known about the T cell reactivity to penicillins. To understand which structural features determine antigenic specificity, we isolated a panel of MHC-restricted, Pen G-reactive T cell clones from different penicillin-allergic patients and tested them for their capacity to proliferate in the presence of other penicillin derivatives. We found that the antigenic epitope consists of both the amide-linked side chain, which is different in every member of the penicillin family, as well as the thiazolidine ring common to all penicillin derivatives. We also demonstrated the presence of two different types of penicillin-specific T cells, one dependent, and the other independent of antigen processing by autologous antigen-presenting cells. Our data strongly suggest that penicillins form part of the epitopes contacting the antigen receptors of T cells.

Carriage of Antibiotic-Resistant Pneumococci among Asian Children: A Multinational Surveillance by the Asian Network for Surveillance of Resistant Pathogens (ANSORP)

Abstract: To investigate the nasal carriage of antibiotic-resistant pneumococci by children, anterior nasal swabs were done for 4963 children <5 years old in 11 countries in Asia and the Middle East. In total, 1105 pneumococci isolates (carriage rate, 22.3%) were collected, 35.8% of which were found to be nonsusceptible to penicillin. Prevalence of penicillin nonsusceptibility was highest in Taiwan (91.3%), followed by Korea (85.8%), Sri Lanka (76.5%), and Vietnam (70.4%). Penicillin resistance was related to residence in urban areas, enrollment in day care, and a history of otitis media. The most common serogroups were 6 (21.5%), 23 (16.5%), and 19 (15.7%). The most common clone, as assessed by pulsed-field gel electrophoresis, was identical to the Spanish 23F clone and to strains of invasive isolates from adult patients. Data in this study documented the high rate of penicillin or multidrug resistance among isolates of pneumococci carried nasally in children in Asia and the Middle East and showed that this is due to the spread of a few predominant clones in the region.