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.

Resistant pneumococci: protecting patients through judicious use of antibiotics.

Abstract: Increasing resistance to antimicrobial agents has occurred among many pathogens, but the emergence of resistant Streptococcus pneumoniae will have the greatest impact on the practice of outpatient medicine. Consequences of resistance include complicated management of acute otitis media and meningitis treatment failures. Pneumococci have acquired resistance to penicillin, third-generation cephalosporins and other antibiotics at an alarming rate; in some areas, 25 percent of isolates are nonsusceptible to penicillin. In areas with high resistance rates, the addition of vancomycin to cefotaxime or ceftriaxone is warranted for empiric treatment of bacterial meningitis. Changes in empiric therapy for pneumonia, bacteremia and otitis media may eventually be necessary. Previous antibiotic use is a risk factor for invasive disease with resistant pneumococci. Patients may be best protected by avoiding unnecessary use of antibiotics. Patient education materials as well as recommendations for avoiding the use of antibiotics for some upper respiratory tract infections are currently being developed to help physicians achieve this goal.

Infection due to Actinobacillus actinomycetemcomitans: 15 cases and review.

Abstract: Actinobacillus actinomycetemcomitans is a small fastidious gram-negative coccobacillus that fails to grow on MacConkey's agar. Slow growth in broth may lead to delays in diagnosis. First described in 1912, A. actinomycetemcomitans has been recognized since 1962 as capable of causing serious infections in humans. Such infections include periodontal infection, soft tissue abscess (often in association with Actinomyces species), and systemic infection, most commonly endocarditis. Fifteen cases and a review of the English-language literature are presented to define the epidemiology and clinical features of infection due to A. actinomycetemcomitans. Therapy for infection due to A. actinomycetemcomitans has most commonly involved ampicillin or penicillin, often in conjunction with an aminoglycoside. However, resistance to penicillin or ampicillin is common. Antimicrobial agents with a high degree of in vitro activity included cefazolin, cefotaxime, cetriaxone, aminoglycosides, and chloramphenicol. Therapy should be guided by clinical response and in vitro susceptibility testing.

Pneumonia Acquired in the Community Through Drug-Resistant Streptococcus pneumoniae

Abstract: The aim of the study was to determine the incidence of and risk factors for drug resistance of Streptococcus pneumoniae, and its impact on the outcome among hospitalized patients of pneumococcal pneumonia acquired in the community. Consecutive patients with culture-proven pneumococcal pneumonia were prospectively studied with regard to the incidence of pneumococcal drug resistance, potential risk factors, and in-hospital outcome variables. A total of 101 patients were studied. Drug resistance to penicillin, cephalosporin, or a macrolide drug was found in pneumococci from 52 of the 101 (52%) patients; 49% of these isolates were resistant to penicillin (16% intermediate resistance, 33% high resistance), 31% to cephalosporin (22% intermediate and 9% high resistance), and 27% to a macrolide drug. In immunocompetent patients, age > 65 yr was significantly associated with resistance to cephalosporin (odds ratio [OR]: 5.0; 95% confidence interval [CI]: 1.3 to 18.8, p = 0.01), and with the presence of > 2 comorbi...

Antimicrobial Susceptibility and Selection of Resistance Among Staphylococcus epidermidis Isolates Recovered from Patients with Infections of Indwelling Foreign Devices

Abstract: Twenty-seven isolates of Staphylococcus epidermidis from patients with prosthetic valve endocarditis or infected cerebrospinal fluid shunts were examined for susceptibility to antimicrobial agents Subpopulations resistant to 20 and 100 mug of methicillin per ml were present in 63% of the isolates (methicillin-resistant isolates) Subpopulations resistant to 20 mug of nafcillin and cephalothin per ml were found in every methicillin-resistant isolate but with frequencies (10(-50 +/- 05) and 10(-64 +/- 09), respectively) which were not always detectable by susceptibility testing Resistance to >/=16 mug of penicillin per ml was found in 80% of isolates Cephalothin, cefazolin, and cefamandole were more active than cefoxitin or cephradine, and gentamicin was more active than tobramycin or amikacin; rifampin was the single most active agent against all isolates There was no difference in susceptibility between prosthetic valve endocarditis and cerebrospinal fluid shunt infection isolates Among methicillin-resistant isolates, the phenotypic expression of resistance to methicillin or nafcillin but not to cephalothin could be enhanced by 48 h of incubation with each drug Isolates containing no methicillin-resistant subpopulations were killed by incubation with methicillin, nafcillin, or cephalothin High-level resistance to rifampin emerged in both methicillin-resistant and methicillin-sensitive isolates after 8 to 24 h of incubation with this drug The presence or absence of antibiotic-resistant subpopulations among S epidermidis isolates and their selection during treatment should be considered when therapy is devised

Antimicrobial profiles of periodontal pathogens isolated from periodontitis patients in the Netherlands and Spain

Abstract: Background and Aim: Antimicrobial resistance of periodontal pathogens towards currently used antibiotics in periodontics has been investigated in a previous study. Microbial resistance in the periodontal microflora was more frequently observed in Spanish patients in comparison with Dutch patients. The aim of the present study was to compare antimicrobial susceptibility profiles of five periodontal bacteria isolated from periodontitis patients in Spain and in the Netherlands. Material and Methods: Subgingival plaque samples from adult patients with periodontitis were collected and cultured on selective and non-selective plates. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Micromonas micros were isolated and used for minimal inhibitory concentration tests using the Epsilometer (E-test) technique. Eight different antibiotics were tested on all bacterial isolates. MIC50 and MIC90 values for each antibiotic and each species were determined and the percentage of resistant strains was calculated. Results: Significantly higher MIC values were noted in Spanish strains of F. nucleatum for penicillin, ciprofloxacin, of P. intermedia for penicillin, amoxicillin and tetracycline, of M. micros for tetracycline, amoxicillin and azithromycin, and of P. gingivalis for tetracycline and ciprofloxacin. Based on breakpoint concentrations, a higher number of resistant strains in Spain were found in F. nucleatum for penicillin, amoxicillin and metronidazole, in Prevotella intermedia for tetracycline and amoxicillin, and in A. actinomycetemcomitans for amoxicillin and azithromycin. Resistance of P. gingivalis strains was not observed for any of the antibiotics tested both in Spain and the Netherlands. Conclusions: Differences exist in the susceptibility profiles of periodontal pathogens isolated from periodontitis patients in Spain and in the Netherlands. This implicates that antibiotic susceptibility testing is necessary to determine efficacy of antimicrobial agents. Also, clinical studies with antibiotics should take these differences into account. The information from the present study indicates that it may not be possible to develop uniform protocols for usage of antibiotics in the treatment of severe periodontitis in the European Union.