Showing papers on "Penicillin published in 2007"

Antimicrobial susceptibilities of Lactobacillus, Pediococcus and Lactococcus human isolates and cultures intended for probiotic or nutritional use

Abstract: Results: Tentative ECOFF values of 13 antibiotics were determined for up to 12 LAB species. Generally, LAB were susceptible to penicillin, ampicillin, ampicillin/sulbactam, quinupristin/dalfopristin, chloramphenicol and linezolid. LAB exhibited broad or partly species-dependent MIC profiles of trimethoprim, trimethoprim/sulfamethoxazole, vancomycin, teicoplanin and fusidic acid. Three probiotic Lactobacillus strains were highly resistant to streptomycin. Although erythromycin, clindamycin and oxytetracycline possessed high antimicrobial activities, 17 Lactobacillus isolates were resistant to one or more of these antibiotics. Eight of them, including six probiotic and nutritional cultures, possessed erm(B) and/or tet(W), tet(M) or unidentified members of the tet(M) group. In vitro intra- and interspecies filter-mating experiments failed to show transfer of resistance determinants.

Brief Communication: Treatment of Enterococcus faecalis Endocarditis with Ampicillin plus Ceftriaxone

Abstract: A 4- to 6-week course of penicillin or ampicillin plus an aminoglycoside is currently recommended for treating enterococcal endocarditis. However, this regimen is ineffective against Enterococcus f...

Impact of the pneumococcal conjugate vaccine on serotype distribution and antimicrobial resistance of invasive Streptococcus pneumoniae isolates in Dallas, TX, children from 1999 through 2005

Abstract: Background: Because the heptavalent pneumococcal conjugate vaccine has reduced vaccine-type invasive pneumococcal disease (IPD) in children, a greater proportion of IPD is now caused by nonvaccine (NVT) serotypes We analyzed the serotypes, antimicrobial resistance profiles and genetic relatedness of Streptococcus pneumoniae responsible for IPD at Children's Medical Center of Dallas Methods: S pneumoniae isolates were collected from January 1, 1999 through December 31, 2005 Incidence of IPD was calculated using inpatient and emergency center admissions to Children's Medical Center of Dallas as the denominator Isolates were serotyped, and their penicillin and cefotaxime susceptibility determined The 19A isolates were further characterized by pulsed-field gel electrophoresis, multilocus sequence typing and determination of penicillin-binding proteins and mef and erm genes Results: The incidence of IPD decreased from 936 cases/100,000 patients in 1999 to a nadir of 41 cases/100,000 patients in 2003 (P < 0001) The number of IPD cases caused by serotype 19A increased, accounting for 40% of the cases of IPD in 2005 Penicillin and cefotaxime susceptibility of IPD isolates did not change from 1999 through 2005 (P = 0687) There was a decrease in penicillin (P < 0001) and cefotaxime (P = 0034) susceptibility in NVT serotypes from 1999 to 2005 Molecular characterization of 19A isolates revealed a predominance of ST-199 (62%) Several highly penicillin-resistant and intermediately cefotaxime-resistant strains emerged in 2004 and 2005 Conclusions: In Dallas, heptavalent pneumococcal conjugate vaccine reduced the incidence of IPD from 1999 to 2005 by reducing the incidence of vaccine-type disease NVT serotypes, particularly 19A, were prevalent and more resistant to antimicrobials in 2004 and 2005

Penicillin: Triumph and Tragedy

Abstract: Introduction 1. Illness, drugs and wonder drugs before penicillin 2. Penicillin from organised science 3. Creating the brand in the era of propaganda 4. Making penicillin across the world 5. The carefree culture and the third industrial revolution 6. Fighting resistance with technology 7. Doctors, patients and the brand 8. Animals, resistance and committees 9. In face of catastrophe Conclusion

Safe use of selected cephalosporins in penicillin-allergic patients: a meta-analysis.

Abstract: Background Recent analysis of clinical data and a clearer understanding of the role of chemical structure in the development of cross-reactivity indicate that the increased risk of an allergic reaction to a cephalosporin in penicillin-allergic patients is smaller than previously postulated. Method Medline and EMBASE databases were searched with the keywords: cephalosporin, penicillin, allergy, and cross-sensitivity for the years 1960 through 2005. Among 219 articles retrieved, 9 served as source material for this evidence-based meta-analysis. Results A significant increase in allergic reactions to cephalothin (odds ratio [OR] = 2.5; 95% confidence interval [CI] = 1.1 to 5.5), cephaloridine (OR = 8.7; CI = 5.9 to 12.8), and cephalexin (OR = 5.8; CI = 3.6 to 9.2), and all first generation cephalosporins plus cefamandole (OR = 4.8; CI = 3.7 to 6.2) were observed in penicillin allergic patients; no increase was observed with second generation cephalosporins (OR = 1.1; CI, 0.6 to 2.1) or third generation cephalosporins (OR = 0.5; CI = 0.2 to 1.1). Clinical challenges, skin testing, and monoclonal antibody studies point to the paramount importance of similarities in side chain structure to predict cross-allergy between cephalosporins and penicillins. Conclusion First-generation cephalosporins have cross-allergy with penicillins, but cross-allergy is negligible with second- and third-generation cephalosporins. Particular emphasis should be placed on the role of chemical structure in determining the risk of cross-reactivity between specific agents.

Occurrence of antimicrobial resistance in bacteria from diagnostic samples from dogs

Abstract: Results: The majority of the antimicrobials prescribed for dogs were broad-spectrum compounds, and extended-spectrum penicillins, cephalosporins and sulphonamides 1 trimethoprim together accounted for 81% of the total amount used for companion animals. Resistance to cephalosporins and amoxicillin with clavulanic acid was very low for all bacterial species examined, except for P. aeruginosa, and resistance to sulphonamides and trimethoprim was low for most species. Among the S. intermedius isolates, 60.2% were resistant to penicillin, 30.2% to fusidic acid and 27.9% to macrolides. Among E. coli isolates, the highest level of resistance was recorded for ampicillin, sulphonamides, trimethoprim, tetracyclines and streptomycin. Certain differences in resistance patterns between isolates from different sites or organs were noticed for E. coli, S. intermedius and Proteus isolates. Conclusions: This investigation provided data on occurrence of antimicrobial resistance in important pathogenic bacteria from dogs, which may be useful for the small animal practitioner. Resistance was low to the compounds that were most often used, but unfortunately, these compounds were broadspectrum. Data on resistance and usage may form a background for the establishment of a set of recommendations for prudent use of antimicrobials for companion animals.

Comparison of BACTEC PLUS Blood Culture Media to BacT/Alert FA Blood Culture Media for Detection of Bacterial Pathogens in Samples Containing Therapeutic Levels of Antibiotics

Abstract: Blood culture bottles with antimicrobial removal systems are recommended for patients who develop fever while on antibiotics. This study compared the ability of Becton Dickinson (Sparks, MD) BACTEC PLUS bottles and bioMerieux (Durham, NC) BacT/Alert FA bottles to effectively remove vancomycin, cefoxitin, ceftriaxone, cefepime, piperacillin-tazobactam, ampicillin, oxacillin, gentamicin, and a combination of gentamicin/penicillin, thus allowing bacterial pathogens to grow. Each bottle was spiked with 10 ml of human blood, antibiotic, and strains of organisms susceptible to the antibiotic evaluated. The organisms used were type strains and clinical isolates of Staphylococcus aureus (methicillin susceptible and resistant), Streptococcus pneumoniae, a viridans streptococcus, Enterococcus faecalis, Enterococcus faecium, Streptococcus agalactiae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Testing was completed in triplicate, using 10 to 100 CFU/ml of organisms with various concentrations of each antibiotic. Two rounds of testing were completed per antibiotic/organism combination. Bottles were mixed and loaded onto their respective instruments as per the manufacturer's instructions. Antimicrobial removal was evaluated on the basis of time to detection of organism growth, for up to 5 days of incubation. Overall, the BacT/Alert FA system recovered 25.1% of strains from test bottles and 96.9% of strains from growth control bottles (no antibiotic added), and the BACTEC PLUS system recovered 95.1% of strains from test bottles and 100% of strains from growth control bottles. Both systems performed well in the detection of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa in the presence of gentamicin. In the presence of ceftriaxone, neither system was able to recover Streptococcus pneumoniae. The ability to remove vancomycin and cefoxitin was also determined by measuring antibiotic levels remaining in bottles after 1 h of incubation. The results demonstrated remaining levels of 72 to 90% of vancomycin and 71 to 72% of cefoxitin in the BacT/Alert system. For the BACTEC system, remaining levels were 0 to 30% of vancomycin and 0% of cefoxitin. Under these simulated conditions, the BACTEC PLUS system was superior to the BacT/Alert FA system in recovering gram-positive and gram-negative bacterial pathogens in the presence of beta-lactam antibiotics, gentamicin/penicillin, and vancomycin.

Brief Communication: Tolerability of Meropenem in Patients with IgE-Mediated Hypersensitivity to Penicillins

Abstract: The authors performed skin tests with penicillin and meropenem in 104 patients with a history of immediate reaction to penicillin. Every patient had a positive skin test result with penicillin, but...

Target Gene Sequencing To Characterize the Penicillin G Susceptibility of Neisseria meningitidis

Abstract: Clinical isolates of Neisseria meningitidis with reduced susceptibility to penicillin G (intermediate isolates, Pen I ) harbor alterations in the penA gene encoding the penicillin binding protein 2 (PBP2). A 402-bp DNA fragment in the 3′ half of penA was sequenced from a collection of 1,670 meningococcal clinical isolates from 22 countries that spanned 60 years. Phenotyping, genotyping, and the determination of MICs of penicillin G were also performed. A total of 139 different penA alleles were detected with 38 alleles that were highly related, clustered together in maximum-likelihood analysis and corresponded to the penicillin G-susceptible isolates. The remaining 101 penA alleles were highly diverse, corresponded to different genotypes or phenotypes, and accounted for 38% of isolates, but no clonal expansion was detected. Analysis of the altered alleles that were represented by at least five isolates showed high correlation with the Pen I phenotype. The deduced amino acid sequence of the corresponding PBP2 comprised five amino acid residues that were always altered. This correlation was not complete for rare alleles, suggesting that other mechanisms may also be involved in conferring reduced susceptibility to penicillin. Evidence of mosaic structures through events of interspecies recombination was also detected in altered alleles. A new website was created based on the data from this work (http://neisseria.org/nm/typing/penA). These data argue for the use of penA sequencing to identify isolates with reduced susceptibility to penicillin G and as a tool to improve typing of meningococcal isolates, as well as to analyze DNA exchange among Neisseria species.

Clinical and bacteriological response to treatment of clinical mastitis with one of three intramammary antibiotics.

Abstract: AIM: To compare the proportions of clinical and bacteriological cure of glands of dairy cows diagnosed with clinical mastitis, following treatment with one of three different intramammary antibiotic preparations. METHODS: Cows from dairy cow herds (n=28) across New Zealand which were diagnosed with clinical mastitis in one or more glands at any stage of lactation were randomly assigned at the cow level within sequentially presented groups of three animals to be treated with one of three intramammary antibiotics. The treatments were 1 g procaine penicillin, 0.25 g cefuroxime, and a combination of 1 g procaine penicillin and 0.5 g dihydrostreptomycin (DHS). All treatments were infused on three occasions at 12-hourly intervals. Duplicate milk samples were collected for bacteriology before initial treatment, and 21–42 days later. Logistic regression or generalised linear mixed models were used to analyse the proportion of cows or quarters retreated for mastitis within 30 days of initial treatment (‘e...

Penicillin skin testing in patients with a history of β-lactam allergy

Abstract: Background Vancomycin and fluoroquinolones are commonly used in patients with a history of penicillin allergy. Objective To determine the safety and utility of penicillin skin testing (PST). Methods Retrospective study of patients with a history of penicillin allergy between April 1, 1999, and September 30, 2004. Penicillin skin testing was performed by means of standard methods using benzylpenicilloyl-polysine, penicillin G, and histamine and saline controls. Results Of 596 patients studied, 25.3% were outpatients, 50.3% were inpatients, and 24.3% were intensive care unit patients. The most common antibiotics used during the time of PST were vancomycin and fluoroquinolones. Results of PST were negative in 88.4% of patients, positive in 8.2%, and indeterminate in 3.4%. One patient (0.17%) developed urticaria immediately after PST. Fifty-five percent of patients with negative PST results were changed to a β-lactam drug, more frequently in the intensive care unit vs the outpatient setting (70.3% vs 8.6%; P P Conclusions Patients with a history of penicillin allergy can safely use β-lactam drugs if negative PST results.

Systematic review of factors contributing to penicillin treatment failure in Streptococcus pyogenes pharyngitis.

Abstract: Objective Review the evidence for various explanations for microbiologic treatment failure following use of penicillin in group A streptococcal (GAS) tonsillopharyngitis. Data Source Systematic review of the literature based on Medline and EMBASE searches, and review of reference lists of included studies. Results The explanations for penicillin treatment failure in GAS tonsillopharyngitis include 1) carrier state, 2) lack of compliance, 3) recurrent exposure, 4) in vivo copathogenicity of β-lactamase–producing normal pharyngeal flora, 5) in vivo bacterial coaggregation, 6) poor antibiotic penetration to tonsillopharyngeal tissue, 7) in vivo eradication of normal protective flora, 8) early initiation of antibiotic therapy resulting in suppression of an adequate host immune response, 9) intracellular localization of GAS, 10) GAS tolerance to penicillin, 11) contaminated toothbrushes or orthodontic appliances, and 12) transmission from the family pet. There is very little type I or II evidence to support any of the above-cited explanations for treatment failure in GAS tonsillopharyngitis; available studies are mostly observational (in patients) or laboratory-based without clinical confirmation. Conclusion Multiple explanations have been offered by investigators to explain penicillin treatment failures in GAS tonsillopharyngitis, but the evidence base to support the proposed explanations is generally weak by current standards. Further research is needed to better understand the mechanism(s) of penicillin treatment failure in GAS tonsillopharyngitis.

Gene expression profiling of the response of Streptococcus pneumoniae to penicillin

Abstract: Objectives: The aim of this study was to identify changes in the gene expression profile of Streptococcus pneumoniae in response to a subinhibitory concentration of penicillin in an effort to better understand mechanisms by which this organism copes with this stress. Methods: S. pneumoniae serotype 2 strain D39 was grown for 1 h in the presence or absence of penicillin at a concentration equivalent to half the MIC (0.03 mg/L). RNA was isolated and gene expression profiles were compared using DNA microarrays. Differential expression of select genes was confirmed by real-time RT‐PCR. Results: A total of 386 genes were found to be responsive to penicillin. Up-regulated genes included those of the ciaR‐ciaH operon, luxS, genes encoding cell envelope proteins and genes of the pst locus. Down-regulated genes included genes involved in competence, genes encoding capsular polysaccharide biosynthesis proteins, genes involved in fatty acid chain elongation and genes of the polyamine transporter operon. Conclusions: Altered expression of these genes reflects a protective response to perturbation of the bacterial cell wall by penicillin. Such genes may represent potential therapeutic targets for enhancing the activity of penicillin against this organism and provide insight into novel mechanisms of penicillin resistance.

Antibiotics for the eradication of Propionibacterium acnes biofilms in surgical infection

Abstract: Objectives: Propionibacterium acnes is increasingly recognized as a cause of delayed infection after spinal instrumentation or shunting for hydrocephalus. Biofilm development by this organism has recently been demonstrated. We therefore investigated the effect of two different courses of three antibiotics (penicillin, rifampicin and linezolid) on mature P. acnes biofilms in vitro. Outcomes were eradication or regrowth after withdrawal of antibiotics, simulating successful treatment and relapse. Methods: P. acnes biofilms were grown on titanium discs for 6 days until mature, then exposed to the antibiotics for either 7 or 14 days before sonication and culture. Further, discs were similarly exposed, but after each course, they were reincubated for a further 9 days to check for regrowth. Results: Penicillin, linezolid and linezolid plus rifampicin eradicated P. acnes biofilms after 14 days, but only penicillin had this effect after 7 days. ‘Relapse’ was prevented only by 14 day courses of penicillin or linezolid plus rifampicin, but not by linezolid alone. Conclusions :F orP. acnes spinal instrumentation infections, either penicillin or linezolid plus rifampicin might be equally effective. For shunt infections, as penicillin does not give therapeutic cerebrospinal fluid concentrations, rifampicin plus linezolid might be the treatment of choice. Linezolid alone appears not to be as effective as penicillin against P. acnes biofilms.

National and Regional Assessment of Antimicrobial Resistance among Community-Acquired Respiratory Tract Pathogens Identified in a 2005-2006 U.S. Faropenem Surveillance Study

Abstract: Surveillance studies conducted in the United States over the last decade have revealed increasing resistance among community-acquired respiratory pathogens, especially Streptococcus pneumoniae, that may limit future options for empirical therapy. The objective of this study was to assess the scope and magnitude of the problem at the national and regional levels during the 2005-2006 respiratory season (the season when community-acquired respiratory pathogens are prevalent) in the United States. Also, since faropenem is an oral penem being developed for the treatment of community-acquired respiratory tract infections, another study objective was to provide baseline data to benchmark changes in the susceptibility of U.S. respiratory pathogens to the drug in the future. The in vitro activities of faropenem and other agents were determined against 1,543 S. pneumoniae isolates, 978 Haemophilus influenzae isolates, and 489 Moraxella catarrhalis isolates collected from 104 U.S. laboratories across six geographic regions during the 2005-2006 respiratory season. Among S. pneumoniae isolates, the rates of resistance to penicillin, amoxicillin-clavulanate, and cefdinir were 16, 6.4, and 19.2%, respectively. The least effective agents were trimethoprim-sulfamethoxazole (SXT) and azithromycin, with resistance rates of 23.5 and 34%, respectively. Penicillin resistance rates for S. pneumoniae varied by region (from 8.7 to 22.5%), as did multidrug resistance rates for S. pneumoniae (from 8.8 to 24.9%). Resistance to beta-lactams, azithromycin, and SXT was higher among S. pneumoniae isolates from children than those from adults. beta-Lactamase production rates among H. influenzae and M. catarrhalis isolates were 27.4 and 91.6%, respectively. Faropenem MICs at which 90% of isolates are inhibited were 0.5 mug/ml for S. pneumoniae, 1 mug/ml for H. influenzae, and 0.5 mug/ml for M. catarrhalis, suggesting that faropenem shows promise as a treatment option for respiratory infections caused by contemporary resistant phenotypes.

Female sex as a risk factor for penicillin allergy.

Abstract: Background Identification of risk factors is an integral part of a physician's evaluation of a patient. Objective To determine whether female sex is an independent risk factor for penicillin allergy. Methods Rates of positive penicillin skin test (PST) results, according to sex, were determined in patients with a history of penicillin allergy undergoing penicillin allergy evaluation with major and minor determinants of penicillin between June 1, 2002, and June 30, 2004. Univariate and multivariate logistic regression analyses were used to calculate unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for sex differences in the rates of positive PST results. Results Of the 1,921 patients, 1,759 underwent PST and 157 did not; 5 medical records were not available for review. The mean patient age was 60 years. Sixty-four patients (4%) had a positive PST reaction; of these, 53 (83%) were females and 11 (17%) were males (OR, 3.6; 95% CI, 1.9–7.2; P P = .001). Conclusion A greater risk of penicillin allergy exists in association with female sex in patients with a history of penicillin allergy.

Galbanic acid from Ferula szowitsiana enhanced the antibacterial activity of penicillin G and cephalexin against Staphylococcus aureus

Abstract: In this study the enhancement effect of Ferula szowitsiana roots' acetone extract on the antibacterial activity of penicillin G and cephalexin was evaluated against Staphylococcus aureus. Disk diffusion and broth dilution methods were used to determine the antibacterial activity of these antibiotics in the absence and presence of plant extract and its various fractions separated by TLC plate. The active component of plant extract involved in enhancement of penicillin G's and cephalexin's activities had Rf=0.336 on a TLC plate. The spectral data (1H-, 13C-NMR) of this compound revealed that this compound was 7-[6-(β-carboxyethyl)-5-isopropylidene-1,2-dimethylcyclo-hexylmethoxy]coumarin (galbanic acid), previously isolated from Ferula assa-foetida. In the presence of sub-inhibitory concentration of galbanic acid (100 μg/ml) the MIC of penicillin G for S. aureus decreased from 64 to 1 (a sixteen four-fold decrease) and for cephalexin from 128 to 1 μg/ml (a one hundred twenty eight-fold decrease). The highest fold decrease in MIC was observed for cephalexin in combination of galbanic acid against test strain. These results signify that the low concentration of galbanic acid (100 μg/ml) potentiates the antimicrobial action of penicillin G and cephalexin suggesting a possible utilization of these compounds in combination therapy against S. aureus.

Use of a DNA Microarray for Simultaneous Detection of Antibiotic Resistance Genes among Staphylococcal Clinical Isolates

Abstract: We developed a multiplex asymmetric PCR (MAPCR)-based DNA microarray assay for characterization of the clinically relevant antibiotic resistance genes leading to penicillin, methicillin, aminoglycoside, macrolide, lincosamide, and streptogramin B (MLS(B)) resistance in staphylococci. The DNA-based assay involves detection of specific conserved regions of the mecA, blaZ (methicillin and penicillin resistance), aac(6')-Ie-aph(2'') (aminoglycoside resistance), ermA and ermC genes (MLS(B) resistance), and the msrA gene (macrolide and streptogramin B resistance). The microarray uses a variable sequence region of the 16S rRNA gene to broadly differentiate between Staphylococcus aureus and other coagulase-negative staphylococci (CoNS). The performance of the microarray was validated with a total of 178 clinically important S. aureus and 237 CoNS isolates, with correlations of 100% for S. aureus to CoNS discrimination and more than 90% for antibiotic resistance between the genotypic analysis determined by the microarray and the phenotype determined by standard methods of species identification and susceptibility testing. The major discrepant results were 17 mecA-positive CoNS and 60 aac(6')-Ie-aph(2'')-positive CoNS isolates measured by microarray that were susceptible to the corresponding antibiotics based on disk diffusion assay. Overall, this microarray-based assay offers a simultaneous, fast (< or =5 h), and accurate identification of antibiotic resistance genes from a single colony, as well as species classification. Our extensive validation of the microarray suggests that it may be a useful tool to complement phenotypic susceptibility testing in clinical laboratories and to survey the spread of antibiotic resistance determinants in epidemiological studies.

Heteroresistance to penicillin in Streptococcus pneumoniae

Abstract: Heteroresistance to beta-lactam antibiotics has been mainly described for staphylococci, for which it complicates diagnostic procedures and therapeutic success. This study investigated whether heteroresistance to penicillin exists in Streptococcus pneumoniae. Population analysis profile (PAP) showed the presence of subpopulations with higher penicillin resistance in four of nine clinical pneumococcal strains obtained from a local surveillance program (representing the multiresistant clones ST179, ST276, and ST344) and in seven of 16 reference strains (representing the international clones Spain(23F)-1, Spain(9V)-3, Spain(14)-5, Hungary(19A)-6, South Africa(19A)-13, Taiwan(23F)-15, and Finland(6B)-12). Heteroresistant strains had penicillin minimal inhibitory concentrations (MICs) (for the majority of cells) in the intermediate- to high-level range (0.19-2.0 mug/ml). PAP curves suggested the presence of subpopulations also for the highly penicillin-resistant strains Taiwan(19F)-14, Poland(23F)-16, CSR(19A)-11, and CSR(14)-10. PAP of bacterial subpopulations with higher penicillin resistance showed a shift toward higher penicillin-resistance levels, which reverted upon multiple passages on antibiotic-free media. Convergence to a homotypic resistance phenotype did not occur. Comparison of two strains of clone ST179 showed a correlation between the heteroresistant phenotype and a higher-penicillin MIC and a greater number of altered penicillin-binding proteins (PBP1a, -2b, and -2x), respectively. Therefore, heteroresistance to penicillin occurs in international multiresistant clones of S. pneumoniae. Pneumococci may use heteroresistance to penicillin as a tool during their evolution to high penicillin resistance, because it gives the bacteria an opportunity to explore growth in the presence of antibiotics before acquisition of resistance genes.

Aminopenicillin-induced exanthema allows treatment with certain cephalosporins or phenoxymethyl penicillin

Abstract: Received 3 December 2006; returned 26 February 2007; revised 20 March 2007; accepted 18 April 2007Objectives: Aminopenicillin-induced exanthema poses a problem in the management of infectious dis-eases. Due to theoretically possible immunological cross-reactivity, all b-lactam drugs, i.e. penicillins,penicillin derivatives and cephalosporins, are usually avoided. The available alternative antibiotics(macrolides, quinolones and glycopeptides) may be less effective, have more side effects, and theiruse increases medical costs. Moreover, their use contributes to the increasing bacterial resistance toantibiotics. The aim of the study is to demonstrate that patients with aminopenicillin-inducedexanthema may receive specific b-lactams for future antibiotic therapy.Methods: Skin testing followed by oral challenges to identify b-lactams that are tolerated by patientsdespite confirmed delayed-type non-immunoglobulin E (IgE)-mediated allergic hypersensitivity to ami-nopenicillins.Results: Sixty-nine out of 71 patients (97.2%) with non-IgE-mediated allergic hypersensitivity to amino-penicillins tolerate cephalosporins without an aminobenzyl side chain such as cefpodoxime or cefix-ime and 51 patients (71.8%) also tolerate phenoxymethyl penicillin.Conclusions: The majority of patients with non-IgE-mediated allergic hypersensitivity to aminopenicil-lins do not cross-react to certain cephalosporins or phenoxymethyl penicillin. Skin and drug challengetests can be helpful to determine individual cross-reactivity.Keywords: drug challenge, drug provocation, non-IgE-mediated allergic hypersensitivity, skin tests

Swedish guidelines for diagnosis and treatment of infective endocarditis

Abstract: Swedish guidelines for diagnosis and treatment of infective endocarditis (IE) by consensus of experts are based on clinical experience and reports from the literature. Recommendations are evidence based. For diagnosis 3 blood cultures should be drawn; chest X-ray, electrocardiogram, and echocardiography preferably transoesophageal should be carried out. Blood cultures should be kept for 5 d and precede intravenous antibiotic therapy. In patients with native valves and suspicion of staphylococcal aetiology, cloxacillin and gentamicin should be given as empirical treatment. If non-staphylococcal etiology is most probable, penicillin G and gentamicin treatment should be started. In patients with prosthetic valves treatment with vancomycin, gentamicin and rifampicin is recommended. Patients with blood culture negative IE are recommended penicillin G (changed to cefuroxime in treatment failure) and gentamicin for native valve IE and vancomycin, gentamicin and rifampicin for prosthetic valve IE, respectively. Isolates of viridans group streptococci and enterococci should be subtyped and MIC should be determined for penicillin G and aminoglycosides. Antibiotic treatment should be chosen according to sensitivity pattern given 2-6 weeks intravenously. Cardiac valve surgery should be considered early, especially in patients with left-sided IE and/or prosthetic heart valves. Absolute indications for surgery are severe heart failure, paravalvular abscess, lack of response to antibiotic therapy, unstable prosthesis and multiple embolies. Follow-up echocardiography should be performed on clinical indications.

Infective Endocarditis Due to Penicillin-Resistant Viridans Group Streptococci

Abstract: Background The emergence of viridans group streptococci that are relatively or fully resistant to penicillin is increasingly being recognized worldwide, but only a scant number of penicillin-resistant isolates have been described as a cause of infective endocarditis. Because of the paucity of data, it has been difficult to define optimal treatment regimens for this syndrome. Thus, recommendations for therapy have largely been made on the basis of consensus opinion. Methods We retrospectively identified a cohort of patients with infective endocarditis due to penicillin-resistant viridans group streptococci who were seen at the Mayo Clinic (Rochester, MN) between January 1967 and April 2006. Demographic characteristics, clinical features, treatment regimens, and outcomes were analyzed. Mean values are shown with standard deviations. Results Twenty-nine patients were identified over the 38.5-year study period. Nineteen patients with native valve endocarditis were cured; 9 of these 19 patients received a 2.3+/-0.4-week antibiotic regimen consisting of penicillin and an aminoglycoside, and 8 of these 19 patients received treatment courses of 5.1+/-1.4 weeks' duration that consisted of either a bimodal combination regimen with a penicillin or ceftriaxone and an aminoglycoside or ceftriaxone monotherapy. Nine of 10 patients with prosthetic valve infection were cured with 4.1+/-0.6-week regimens that consisted of either a combination regimen or monotherapy with vancomycin or ceftriaxone. Mean duration of follow-up after hospital discharge was 9.1 years. Conclusions Outcomes of this relatively large population of patients with endocarditis with a prolonged duration of follow-up indicate that the application of current treatment guidelines should be successful in most patients.