Showing papers on "Penicillin published in 2016"

Mechanistic Study of the Synergistic Antibacterial Activity of Combined Silver Nanoparticles and Common Antibiotics

Abstract: A combination of silver nanoparticles (AgNPs) and an antibiotic can synergistically inhibit bacterial growth, especially against the drug-resistant bacteria Salmonella typhimurium. However, the mechanism for the synergistic activity is not known. This study chooses four classes of antibiotics, β-lactam (ampicillin and penicillin), quinolone (enoxacin), aminoglycoside (kanamycin and neomycin), and polykeptide (tetracycline) to explore their synergistic mechanism when combined with AgNPs against the multidrug-resistant bacterium Salmonella typhimurium DT 104. Enoxacin, kanamycin, neomycin, and tetracycline show synergistic growth inhibition against the Salmonella bacteria when combined with AgNPs, while ampicillin and penicillin do not. UV–vis and Raman spectroscopy studies reveal that all these four synergistic antibiotics can form complexes with AgNPs, while ampicillin and penicillin do not. The presence of tetracycline enhances the binding of Ag to Salmonella by 21% and Ag+ release by 26% in comparison t...

Prophylaxis against group a streptococcal infections in rheumatic fever patients

Abstract: There are two effective methods now available for the prevention of rheumatic fever or its recurrences. Prompt and vigorous treatment of the initiating streptococcal infection with one of the antibiotic drugs may prevent the complication of rheumatic fever, or the maintenance of continuous antibiotic therapy in the rheumatic subject may prevent recurrences by affording protection against infection by group A streptococci.1 Penicillin promises to be the antibiotic of choice for the prevention of rheumatic fever by either of the above methods for several reasons: its action is bactericidal rather than bacteriostatic 2; the streptococcal pharyngeal carrier state is eliminated most effectively by treatment with adequate doses of penicillin 3; strains of group A streptococci resistant to penicillin have not emerged, despite the widespread use of this drug 4; and fatal or serious toxic reactions are relatively rare. The problem of employing penicillin as a prophylactic agent is largely a practical one. Current methods for maintaining continuous prophylaxis with penicillin in¬ volve oral administration of relatively large doses, once to three times daily, with the patient in the fasting state.le The success of such treatment depends largely on the pa¬ tient's strict adherence to this regimen without interrup¬ tion. In addition, only a fraction (about one-fifth) of the dose of penicillin administered is absorbed and the oral route is, consequently, costly and wasteful. Parenteral administration of available repository procaine penicillin preparations has not been employed for continuous pro¬ phylaxis because of the frequency with which injections would be required. If, however, penicillin could be main¬ tained in the tissues for protracted periods by means of single injections given at infrequent intervals, parenteral administration should prove economical and practical. Treatment of the initiating streptococcal pharyngitis with penicillin to prevent the subsequent development of rheumatic fever usually requires repeated intramuscular injections or large orally administered doses of penicillin for about 10 days." In routine medical practice, bacterio¬ logical confirmation of the streptococcal etiology of pharyngitis is rarely obtained, and penicillin often is not administered for an adequate period. There would, there¬ fore, be considerable practical advantage in a prepara¬ tion with which successful treatment of streptococcal respiratory infection could be obtained by a single intra¬ muscular injection. Recently, a new repository penicillin compound was synthesized that provides detectable levels of penicillin in the blood of humans for prolonged periods following single intramuscular injections.7 N,N' dibenzylethylenediamine dipenicillin G ("bicillin") is a sparingly soluble

Penicillin skin testing in hospitalized patients with β-lactam allergies: Effect on antibiotic selection and cost

Abstract: Background A history of a penicillin allergy generally leads to the use of broad-spectrum antibiotics that may increase complications and cost Objective To determine the cost-effectiveness of performing penicillin skin testing (PST) Methods A retrospective analysis was conducted on adult inpatients with a β-lactam allergy who underwent PST and oral challenge performed by an allergist The primary outcome was overall antibiotic cost savings for patients switched to a β-lactam antibiotic (BLA) Secondary outcomes included subsequent admissions that required antibiotics and total number of days a BLA was prescribed Results Fifty patients had PST performed (mean age, 62 years) The most common β-lactam allergy reported was penicillin (92%) Cutaneous reactions were reported in 54% of patients, and 56% had a reaction more than 20 years ago Fifty percent of patients had aztreonam prescribed before PST The results of PST were negative in all patients, and 1 patient had anaphylactic symptoms during the oral amoxicillin challenge (98% skin test or oral challenge negative) Thirty-seven patients (755%) were changed to a BLA Overall cost savings were $11,005 ($297 per patient switched to a BLA) There were 31 subsequent admissions that required antibiotics for patients who tested negative on skin test and oral challenge A BLA was prescribed in 22 of 31 readmissions, totaling 147 days of BLA therapy Conclusion After the implementation of a PST protocol, we observed a decrease in non-BLA use in patients with previously documented β-lactam allergy PST is a safe and cost-effective procedure to serve as a negative predictor test for penicillin hypersensitivity mediated by IgE

Different antibiotic treatments for group A streptococcal pharyngitis

Abstract: Background Antibiotics provide only modest benefit in treating sore throat, although effectiveness increases in participants with positive throat swabs for group A beta-haemolytic streptococci (GABHS). It is unclear which antibiotic is the best choice if antibiotics are indicated. Objectives To assess the evidence on the comparative efficacy of different antibiotics in: (a) alleviating symptoms (pain, fever); (b) shortening the duration of the illness; (c) preventing relapse; and (d) preventing complications (suppurative complications, acute rheumatic fever, post-streptococcal glomerulonephritis). To assess the evidence on the comparative incidence of adverse effects and the risk-benefit of antibiotic treatment for streptococcal pharyngitis. Search methods We searched CENTRAL (2016, Issue 3), MEDLINE Ovid (1946 to March week 3, 2016), Embase Elsevier (1974 to March 2016), and Web of Science Thomson Reuters (2010 to March 2016). We also searched clinical trials registers. Selection criteria Randomised, double-blind trials comparing different antibiotics and reporting at least one of the following: clinical cure, clinical relapse, or complications or adverse events, or both. Data collection and analysis Two review authors independently screened trials for inclusion, and extracted data using standard methodological procedures as recommended by Cochrane. We assessed risk of bias of included studies according to the methods outlined in the Cochrane Handbook for Systematic Reviews of Interventions and used the GRADE tool to assess the overall quality of evidence for the outcomes. Main results We included 19 trials (5839 randomised participants); seven compared penicillin with cephalosporins, six compared penicillin with macrolides, three compared penicillin with carbacephem, one trial compared penicillin with sulphonamides, one trial compared clindamycin with ampicillin, and one trial compared azithromycin with amoxicillin in children. All included trials reported clinical outcomes. Reporting of randomisation, allocation concealment, and blinding was poor in all trials. The overall quality of the evidence assessed using the GRADE tool was low for the outcome 'resolution of symptoms' in the intention-to-treat (ITT) analysis and very low for the outcomes 'resolution of symptoms' of evaluable participants and for adverse events. We downgraded the quality of evidence mainly due to lack of (or poor reporting of) randomisation or blinding, or both, heterogeneity, and wide confidence intervals (CIs). There was a difference in symptom resolution in favour of cephalosporins compared with penicillin (evaluable patients analysis odds ratio (OR) for absence of resolution of symptoms 0.51, 95% CI 0.27 to 0.97; number needed to treat to benefit (NNTB) 20, N = 5, n = 1660; very low quality evidence). However, this was not statistically significant in the ITT analysis (OR 0.79, 95% CI 0.55 to 1.12; N = 5, n = 2018; low quality evidence). Clinical relapse was lower for cephalosporins compared with penicillin (OR 0.55, 95% CI 0.30 to 0.99; NNTB 50, N = 4, n = 1386; low quality evidence), but this was found only in adults (OR 0.42, 95% CI 0.20 to 0.88; NNTB 33, N = 2, n = 770). There were no differences between macrolides and penicillin for any of the outcomes. One unpublished trial in children found a better cure rate for azithromycin in a single dose compared to amoxicillin for 10 days (OR 0.29, 95% CI 0.11 to 0.73; NNTB 18, N = 1, n = 482), but there was no difference between the groups in ITT analysis (OR 0.76, 95% CI 0.55 to 1.05; N = 1, n = 673) or at long-term follow-up (evaluable patients analysis OR 0.88, 95% CI 0.43 to 1.82; N = 1, n = 422). Children experienced more adverse events with azithromycin compared to amoxicillin (OR 2.67, 95% CI 1.78 to 3.99; N = 1, n = 673). Compared with penicillin carbacephem showed better symptom resolution post-treatment in adults and children combined (ITT analysis OR 0.70, 95% CI 0.49 to 0.99; NNTB 14, N = 3, n = 795), and in the subgroup analysis of children (OR 0.57, 95% CI 0.33 to 0.99; NNTB 8, N = 1, n = 233), but not in the subgroup analysis of adults (OR 0.75, 95% CI 0.46 to 1.22, N = 2, n = 562). Children experienced more adverse events with macrolides compared with penicillin (OR 2.33, 95% CI 1.06 to 5.15; N = 1, n = 489). Studies did not report on long-term complications so it was unclear if any class of antibiotics was better in preventing serious but rare complications. Authors' conclusions There were no clinically relevant differences in symptom resolution when comparing cephalosporins and macrolides with penicillin in the treatment of GABHS tonsillopharyngitis. Limited evidence in adults suggests cephalosporins are more effective than penicillin for relapse, but the NNTB is high. Limited evidence in children suggests carbacephem is more effective than penicillin for symptom resolution. Data on complications are too scarce to draw conclusions. Based on these results and considering the low cost and absence of resistance, penicillin can still be regarded as a first choice treatment for both adults and children. All studies were in high-income countries with low risk of streptococcal complications, so there is need for trials in low-income countries and Aboriginal communities where risk of complications remains high.

The synergy and mode of action of quercetin plus amoxicillin against amoxicillin-resistant Staphylococcus epidermidis.

Abstract: Staphylococcus epidermidis is one of the most multiple resistances to antibiotics in the recent years. Therefore, practically-prescribed antibiotics in the treatment of these strains are not effective. Plant-derived antibacterial is one of the most interesting sources of new therapeutics. The present study was to investigate antibacterial, synergy and modes of action of quercetin and amoxicillin against amoxicillin-resistant Staphylococcus epidermidis (ARSE). The MICs, checkerboard assay, viability curves, cytoplasmic membrane (CM) permeability, enzyme assay, transmission electron microscopy, confocal microscopy and FT-IR microspectroscopy measurement was performed. The MICs of amoxicillin, penicillin, quercetin and kaempferol against all ARSE strains were 16, 200, 256-384 and >1024 μg/mL respectively. Synergistic effects were exhibited on amoxicillin plus quercetin and penicillin plus kaempferol against these strains at FIC index 0.50 and <0.38 respectively. The synergistic activity of quercetin plus amoxicillin was confirmed by the viable count. This combination increased CM permeability, caused marked morphological, peptidoglycan and cytoplasmic membrane damage, increased protein amide I and II, but decreased fatty acid in bacterial cells. The quercetin had an inhibitory activity against β-lactamase. So, these findings are the first report that quercetin has the synergistic effect with amoxicillin against ARSE via four modes of actions, inhibit peptidoglycan synthesis and β-lactamases activity, increase CM permeability and protein amide I and II but decrease fatty acid in bacterial cells. Of course, this flavonol has the dominant potential to develop a brand-new collateral phytochemical agent plus amoxicillin to treat ARSE. Future work should focus on the bioavailability, efficacy and toxicity in animal and human studies, as well as, the synergistic effect on blood and tissue should be evaluated and achieved.

Aeromonas spp.: An Emerging Nosocomial Pathogen.

Abstract: Aeromonads are hallophillic, nonacid fast, nonspore forming, Gram-negative rods which are widely distributed in the soil, foodstuffs, and aquatic environment. Since times immemorial, they are important zoonotic pathogens of poikilotherms but are now emerging as important human pathogens. These emerging enteric pathogens flourish in the water distribution system by forming biofilms. They possess large number of virulence factors including inherent resistance to various antibiotics and ability to form biofilms using quorum sensing. These properties make them easy pathogens for human infections. Aeromonads are important enteric pathogens, but, with the growing level of immunosuppression in the population, they have been associated with various extraintestinal infections, such as skin and soft-tissue infections, traumatic wound infections, and lower respiratory tract/urinary tract infections. The average annual incidence of bacteremia in Southern Taiwan due to Aeromonas spp. was 76 cases/million inhabitants between 2008 and 2010. However, the incidence reported from Western countries is much lower. The case fatality rate among patients with Aeromonas bacteremia ranges from 27.5 to 46%. Aeromonads are universally resistant to the narrow-spectrum penicillin group of antibiotics such as penicillin, ampicillin, carbenicillin, and ticarcillin. They are however susceptible to piperacillin, azlocillin, second and third generation cephalosporins, and carbapenems. Most of the Aeromonas species are susceptible to aminoglycosides, tetracycline, chloramphenicol, trimethoprim-sulfamethoxazole, quinolones, and monobactams. This manuscript is a comprehensive systematic review of the literature available on Aeromonas spp.

The Impact of Reporting a Prior Penicillin Allergy on the Treatment of Methicillin-Sensitive Staphylococcus aureus Bacteremia

Abstract: Background Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia is a morbid infection with mortality benefit from receipt of parenteral β-lactam therapy. A substantial portion of MSSA bacteremia patients report penicillin allergy, but infrequently have true allergy. Objective To determine the frequency and predictors of optimal and adequate therapy in patients with MSSA bacteremia. Design Retrospective cohort. Participants Adult inpatients with MSSA bacteremia, January 2009 through October 2013. Main Measures The primary measure was a trial of optimal therapy (OT), defined as ≥3 inpatient days or discharge on any first-line agents (nafcillin, oxacillin, cefazolin, or penicillin G, if susceptible). The secondary measure was completion of adequate therapy (AT), defined as ≥10 inpatient days or discharge on an agent appropriate for MSSA bacteremia. Data were electronically gathered with key variables manually validated through chart review. Log-binomial regression models were used to determine the frequency and predictors of outcomes. Key Results Of 456 patients, 346 (76%) received a trial of OT. Patients reporting penicillin allergy (13%) were less likely to receive OT trial than those without penicillin allergy (47% vs. 80%, p <0.001). Adjusting for other factors, penicillin allergy was the largest negative predictor of OT trial (RR 0.64 [0.49, 0.83]). Infectious Disease (ID) consultation was the largest positive predictor of OT trial across all patients (RR 1.34 [1.14, 1.57]). Allergy/Immunology consultation was the single most important predictor of OT trial among patients reporting penicillin allergy (RR 2.33 [1.44, 3.77]). Of 440 patients, 391 (89%) completed AT, with ID consultation the largest positive predictor of the outcome (RR 1.28 [1.15, 1.43]). Conclusions Nearly 25% of patients with MSSA bacteremia did not receive OT trial and about 10% did not receive AT completion. Reported penicillin allergy reduced, and ID consult increased, the likelihood of OT. Allergy evaluation, coupled with ID consultation, may improve outcomes in MSSA bacteremic patients.

Cross-reactivity and tolerability of aztreonam and cephalosporins in subjects with a T cell-mediated hypersensitivity to penicillins

Abstract: Background The few studies performed in adults with T cell–mediated hypersensitivity to penicillins have found a rate of cross-reactivity with cephalosporins ranging from 2.8% to 31.2% and an absence of cross-reactivity with aztreonam. Objective We sought to evaluate the possibility of using cephalosporins and aztreonam in subjects with documented delayed hypersensitivity to penicillins who especially require them. Methods We conducted a prospective study of 214 consecutive subjects who had 307 nonimmediate reactions to penicillins (almost exclusively aminopenicillins) and had positive patch test and/or delayed-reading skin test responses to at least 1 penicillin reagent. To assess cross-reactivity with cephalosporins and aztreonam and the tolerability of such alternative β-lactams, all subjects underwent skin tests with cephalexin, cefaclor, cefadroxil, cefuroxime, ceftriaxone, and aztreonam. Subjects with negative responses were challenged with the alternative β-lactams concerned. Results All subjects had negative skin test results to cefuroxime, ceftriaxone, and aztreonam and tolerated challenges. Forty (18.7%) of the 214 subjects had positive skin test responses to at least 1 aminocephalosporin. Of the 174 subjects with negative responses, 170 underwent challenges; 1 reacted to cefaclor. Conclusions These data demonstrate a rate of cross-reactivity between aminopenicillins and aminocephalosporins (ie, cephalexin, cefaclor, and cefadroxil) of around 20%, as well as the absence of cross-reactivity between penicillins and cefuroxime, ceftriaxone, and aztreonam in all subjects with T cell–mediated hypersensitivity to penicillins, almost exclusively aminopenicillins. Therefore these subjects could be treated with cefuroxime, ceftriaxone, and aztreonam. In those who especially require cephalosporin or aztreonam treatment, however, we recommend pretreatment skin tests because negative responses indicate tolerability.

Is Vancomycin-only Prophylaxis for Patients With Penicillin Allergy Associated With Increased Risk of Infection After Arthroplasty?

Abstract: Preoperative antibiotic prophylaxis remains one of the most important strategies for prevention of postoperative infection. In patients with penicillin allergy, alternative medications such as vancomycin are often used despite reduced antimicrobial coverage and recent literature questioning the efficacy of vancomycin monotherapy. (1) Are patients who receive vancomycin alone for penicillin allergy at greater odds of developing surgical site infection (SSI) as compared with patients who receive cefazolin for prophylaxis before total joint arthroplasty (TJA) without a patient-reported allergy? (2) What organism profile is associated with vancomycin monotherapy? We performed a retrospective study of 10,391 primary TJAs performed between 2005 and 2014 at two institutions with a minimum of 1-year followup. Patients reporting penicillin or cephalosporin allergy were electronically queried from the anesthesia note. The odds of deep SSI and causative organisms were compared using multivariate analysis between β-lactam-allergic patients receiving vancomycin and nonallergic patients receiving cefazolin. After controlling for potential confounders, including comorbidities, we found that vancomycin alone did not affect the odds of deep SSI development (adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.67–1.43; p = 0.907). Although the overall odds of deep SSI were not different for patients receiving vancomycin versus cefazolin, we found that vancomycin was associated with a reduced risk of infection with Gram-positive organisms (adjusted OR, 0.25 [CI, 0.10–0.62]; p = 0.003) and antibiotic-resistant organisms (adjusted OR, 0.10 [CI, 0.01–0.88]; p = 0.038). Vancomycin also demonstrated an increased risk of Gram-negative infection in bivariate analysis (OR, 2.42 [CI, 1.01–5.82]; p = 0.049) compared to cefazolin. With the numbers available, vancomycin alone during elective primary TJA does not seem to result in a higher rate of subsequent deep SSI. However, patients who received vancomycin alone demonstrated reduced odds of Gram-positive organisms and methicillin-resistant Staphylococcus aureus. Vancomycin monotherapy can be used without increasing the risk of deep SSI; however, it should only be used in patients who require vancomycin, eg, anaphylactic reactions to penicillin resulting from the potential for the emergence of organism resistance and nephrotoxicity. Future studies are needed that use registry and large database studies to refute or confirm the preliminary findings of this study and determine if vancomycin monotherapy influences the risk of periprosthetic joint infection. Level III, therapeutic study.

Multidrug-Resistant Corynebacterium striatum Associated with Increased Use of Parenteral Antimicrobial Drugs.

Abstract: Corynebacterium striatum is an emerging multidrug-resistant bacteria. We retrospectively identified 179 isolates in a clinical database. Clinical relevance, in vitro susceptibility, and length of parenteral antimicrobial drug use were obtained from patient records. For patients with hardware- or device-associated infections, those with C. striatum infections were matched with patients infected with coagulase-negative staphylococci for case–control analysis. A total of 87 (71%) of 121 isolates were resistant to all oral antimicrobial drugs tested, including penicillin, tetracycline, clindamycin, erythromycin, and ciprofloxacin. When isolated from hardware or devices, C. striatum was pathogenic in 38 (87%) of 44 cases. Patients with hardware-associated C. striatum infections received parenteral antimicrobial drugs longer than patients with hardware-associated coagulase-negative staphylococci infections (mean ± SD 69 ± 5 days vs. 25 ± 4 days; p<0.001). C. striatum commonly shows resistance to antimicrobial drugs with oral bioavailability and is associated with increased use of parenteral antimicrobial drugs.

Resistance to β-Lactams in Neisseria ssp Due to Chromosomally Encoded Penicillin-Binding Proteins.

Abstract: Neisseria meningitidis and Neisseria gonorrhoeae are human pathogens that cause a variety of life-threatening systemic and local infections, such as meningitis or gonorrhoea. The treatment of such infection is becoming more difficult due to antibiotic resistance. The focus of this review is on the mechanism of reduced susceptibility to penicillin and other β-lactams due to the modification of chromosomally encoded penicillin-binding proteins (PBP), in particular PBP2 encoded by the penA gene. The variety of penA alleles and resulting variant PBP2 enzymes is described and the important amino acid substitutions are presented and discussed in a structural context.

Methicillin resistant Staphylococcus aureus in Ethiopia: a meta-analysis

Abstract: The burden of methicillin resistant Staphylococcus aureus is a major public health concern worldwide; however the overall epidemiology of multidrug resistant strains is neither coordinated nor harmonized, particularly in developing countries including Ethiopia. Therefore, the aim of this meta-analysis was to assess the burden of methicillin resistant Staphylococcos aureus and its antibiotic resistance pattern in Ethiopia at large. PubMed, Google Scholar, and lancet databases were searched and a total of 20 studies have been selected for meta-analysis. Six authors have independently extracts data on the prevalence of methicillin resistant Staphylococcus aureus among clinical isolates of Staphylococcus aureus. Statistical analysis was achieved by using Open meta-analyst (version 3.13) and Comprehensive meta-analysis (version 3.3) softwares. The overall prevalence of methicillin resistant Staphylococcus aureus and its antibiotic resistance pattern were pooled by using the forest plot, table and figure with 95% CI. The pooled prevalence of methicillin resistant Staphylococcus aureus was 32.5% (95% CI, 24.1 to 40.9%). Moreover, methicillin resistant Staphylococcus aureus strains were found to be highly resistant to penicillin, ampicillin, erythromycin, and amoxicillin, with a pooled resistance ratio of 99.1, 98.1, 97.2 and 97.1%, respectively. On the other hand, comparably low levels of resistance ratio were noted to vancomycin, 5.3%. The overall burden of methicillin resistant Staphylococcus aureus is considerably high, besides these strains showed extreme resistance to penicillin, ampicillin, erythromycin and amoxicillin. In principle, appropriate use of antibiotics, applying safety precautions are the key to reduce the spread of multidrug resistant strains, methicillin resistant Staphylococcus aureus in particular.

Changing Epidemiology of Group B Streptococcus Susceptibility to Fluoroquinolones and Aminoglycosides in France

Abstract: Group B Streptococcus (GBS) is the leading cause of neonatal invasive infections and an emerging pathogen in the elderly. Our objectives were to describe the evolution of GBS resistance to antibiotics in France and to investigate the emergence of fluoroquinolone (FQ)-resistant isolates. A total of 8,757 unrelated GBS isolates were collected and tested for antibiotic susceptibility from 2007 to 2014 according to EUCAST recommendations. All isolates were susceptible to penicillin G, amoxicillin, and vancomycin. Resistance to macrolides decreased from 47.0% to 30.0%, whereas high-level resistance to aminoglycosides, especially amikacin, increased from 6.4% to 8.8% and 24 isolates (0.3%) were highly resistant to gentamicin. FQ resistance gradually increased from 0.2% in 2007 (n = 1) to 1.5% in 2014 (n = 18, P < 0.01). Capsular polysaccharide (CPS) genotyping, multilocus sequence typing, and sequencing of the quinolone resistance-determining region (QRDR) showed that GBS isolates of sequence type 19 (ST-19) CPS type V were largely overrepresented in FQ-resistant isolates (n = 30, 45.5%). All 30 strains displayed the same QRDR mutations and were often associated with cross-resistance to macrolides (93.3%) and gentamicin (30%). In conclusion, we report the rise of FQ- and aminoglycoside-resistant GBS in France over an 8-year study period, an evolution likely linked to the clonal expansion of ST-19 CPS V-resistant isolates. This study emphasizes the need for a continuous surveillance of GBS epidemiology and antibiotic susceptibility.

Positive penicillin allergy testing results: a systematic review and meta-analysis of papers published from 2010 through 2015.

Abstract: β-lactam antibiotics are the most widely used group of antibiotics, given their effectiveness for the most common bacterial pathogens and their relatively low price. Adverse reactions, mainly cutaneous, are often reported to be associated with their use and hence, less effective and usually more costly alternative antibiotics are prescribed. However, it is not clear what is the risk of immediate immune-mediated (i.e. developing within one hour of administration) and potentially life-threatening reactions among those using β-lactam antibiotic. We conducted a systematic review to assess the prevalence of immediate adverse reactions to β-lactam antibiotics, specifically penicillin derivatives, in patients with a reported adverse reaction to β-lactam antibiotics. In addition, we determined the effect of age on the prevalence of immediate reactions. Assessing the true risk of using β-lactam antibiotics in patients with a reported allergy could prevent physicians from unnecessarily discouraging the use of β-lactam antibiotics. We conducted a systematic review and a meta-analysis using the PubMed, OVID, and Embase databases of work published in English and in French in the last 5 years. Studies were only eligible if they established the prevalence of immediate penicillin reactions with skin testing or challenges in case of negative skin tests. The meta-analysis was conducted using Stata version 12.0. The prevalence of immediate reactions to penicillin derivatives in patients reporting a β-lactam hypersensitivity is 1.98% (95%CI; 1.35%, 2.60%) in the pediatric (under 18 years old) group, 7.78% (95%CI; 6.53%, 9.04%) in the adult group, and 2.84% (95%CI; 1.77%, 3.91%) in the combined group, as tested in various studies, using skin tests and oral challenges. The I(2) value ranged between 87.2% and 97.0%. Our results indicate that the prevalence of immediate reactions is higher in adults than in children. However, wide confidence intervals and a large study heterogeneity preclude conclusive estimates.

Evaluation of Antimicrobial Resistance in Staphylococcus aureus Isolates by Years

Abstract: Objective. Recently, community and hospital-acquired infections with Staphylococcus aureus have increased and raised antibiotic resistant isolates. In this study, we aimed to evaluate the antibiotic resistance profile of S. aureus isolates over several years in various clinical specimens from our hospital. Materials and Methods. S. aureus strains from 2009 to 2014 were isolated from various clinical samples at Yuzuncu Yil University, Dursun Odabas Medical Center, Microbiology Laboratory, and their antibiotic susceptibility test results were retrospectively investigated. The isolates were identified by conventional methods, and antibiotic susceptibility tests were performed by the Phoenix (Becton Dickinson, USA) automated system method according to Clinical and Laboratory Standards Institute (CLSI) standards. Results. A total of 1,116 S. aureus isolates were produced and methicillin-resistant S. aureus (MRSA) to 21% of all S. aureus isolates between 2009 and 2014. According to the results of susceptibility tests of all isolates of S. aureus, they have been identified as sensitive to vancomycin, daptomycin, linezolid, and levofloxacin. While the resistance rates to nitrofurantoin, quinupristin-dalfopristin, and trimethoprim-sulfamethoxazole were determined as 0.3%, 2.4%, and 6%, respectively, resistance rates to penicillin, erythromycin, rifampicin, gentamicin, and clindamycin were determined as 100%, 18%, 14%, 14%, and 11%, respectively. The highest percentage of methicillin resistance was determined as 30% in 2009, and the resistance was determined to have decreased in subsequent years (20%, 16%, 13%, 19%, and 21%) (p < 0.001). Conclusion. Currently, retrospective evaluations of causes of nosocomial infection should be done periodically. We think that any alteration of resistance over the years has to be identified, and all centers must determine their own resistance profiles, in order to guide empirical therapies. Reducing the rate of antibiotic resistance will contribute to reducing the cost of treatment.

Antimicrobial susceptibility monitoring of dermatological bacterial pathogens isolated from diseased dogs and cats across Europe (ComPath results)

Abstract: Aims The ComPath project is a pan-European programme dedicated to the monitoring of antimicrobial susceptibility of pathogens from diseased dogs and cats using standardized methods and centralized minimum inhibitory concentration (MIC) determination. Here, the susceptibility of major pathogens is reported from antimicrobial nontreated animals with acute clinical signs of skin, wound or ear infections in 2008–2010. Methods and Results MICs were determined by agar dilution for commonly used antibiotics and interpreted using CLSI breakpoints, if available. Of the 1408 strains recovered, the main canine species was Staphylococcus pseudintermedius, followed by Pseudomonas and Streptococcus. In cats, Pasteurella multocida and Staph. pseudintermedius were most prevalent. For Staph. pseudintermedius, resistance was 18·4–25·2% for penicillin, clindamycin and chloramphenicol, but below 11% for ampicillin, amoxi/clav and fluoroquinolones. For Staphylococcus aureus, beta-lactam resistance was high (26·7–62·1%) but low (0·0–4·4%) for other antibiotics. 6·3% of Staph. pseudintermedius and 5·4% of Staph. aureus were confirmed mecA-positive. Gentamicin and fluoroquinolones exhibited moderate activity against Pseudomonas aeruginosa. For streptococci, resistance was absent/very low for penicillin, ampicillin, chloramphenicol and fluoroquinolones. For Escherichia coli, resistance was low to fluoroquinolones, chloramphenicol and gentamicin. No resistance was observed in Past. multocida. Conclusions Overall, antimicrobial resistance was low in skin and soft tissue infections in dogs and cats. The results show the need for ongoing monitoring. Significance and Impact of the Study The results are a reference baseline for future surveillance. The paucity of clinical breakpoints underlines the need to set breakpoints for relevant antibiotics.

Antimicrobial Susceptibility Patterns of Environmental Streptococci Recovered from Bovine Milk Samples in the Maritime Provinces of Canada

Abstract: Determination of antimicrobial susceptibility of bovine mastitis pathogens is important for guiding antimicrobial treatment decisions and for the detection of emerging resistance. Environmental streptococci are ubiquitous in the farm environment and are a frequent cause of mastitis in dairy cows. The aim of the study was to determine patterns of antimicrobial susceptibility among species of environmental streptococci isolated from dairy cows in the Maritime Provinces of Canada. The collection consisted of 192 isolates identified in milk samples collected from 177 cows originating from 18 dairy herds. Results were aggregated into: 1) Streptococcus uberis (n = 70), 2) Streptococcus dysgalactiae (n = 28), 3) other Streptococci spp. (n = 35), 4), Lactococcus spp. (n = 32), and 5) Enterococcus spp. (n = 27). Minimum inhibitory concentrations (MIC) were determined using the Sensititre microdilution system and mastitis plate format. Multilevel logistic regression models were used to analyze the data, with antimicrobial susceptibility as the outcome. The proportion of susceptible Streptococcus uberis ranged from 23% (for penicillin) to 99% (for penicillin/novobiocin), with a median of 82%. All Streptococcus dysgalactiae were susceptible to all antimicrobials except for penicillin (93% susceptible) and tetracycline (18% susceptible). The range of susceptibility for other Streptococcus spp. was 43% (for tetracycline) to 100%, with a median percent susceptibility of 92%. Lactococcus spp. isolates displayed percent susceptibilities ranging from 0% (for penicillin) to 97% (for erythromycin), median 75%. For the antimicrobials tested, the MIC were higher for Enterococcus spp. than for the other species. According to the multilevel models, there was a significant interaction between antimicrobial and bacterial species, indicating that susceptibility against a particular antimicrobial varied among the species of environmental streptococci and vice versa. Generally, susceptibility decreased with increasing within-herd average somatic cell count, isolates recovered in mid-lactation were more susceptible that isolates recovered in early lactation, and isolates recovered in samples collected post-clinical mastitis were more susceptible than isolates recovered from non-clinical lactating quarters. The results of this research support continued susceptibility of environmental streptococci to beta-lactam antimicrobials. A departure from the expected susceptibility to beta-lactams was the apparent reduced susceptibility of Streptococcus uberis to penicillin.

Identification of Penicillin G Metabolites under Various Environmental Conditions Using UHPLC-MS/MS.

Abstract: In this work, we investigate the stability of penicillin G in various conditions including acidic, alkaline, natural acidic matrices and after treatment of citrus trees that are infected with citrus greening disease. The identification, confirmation, and quantitation of penicillin G and its various metabolites were evaluated using two UHPLC-MS/MS systems with variable capabilities (i.e., Thermo Q Exactive Orbitrap and Sciex 6500 QTrap). Our data show that under acidic and alkaline conditions, penicillin G at 100 ng/mL degrades quickly, with a determined half-life time of approximately 2 h. Penillic acid, penicilloic acid, and penilloic acid are found to be the most abundant metabolites of penicillin G. These major metabolites, along with isopenillic acid, are found when penicillin G is used for treatment of citrus greening infected trees. The findings of this study will provide insight regarding penicillin G residues in agricultural and biological applications.

Antibacterial Activity and Antibiotic-Enhancing Effects of Honeybee Venom against Methicillin-Resistant Staphylococcus aureus

Abstract: Methicillin-resistant Staphylococcus aureus (MRSA), along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in vitro activities of bee venom (BV), alone or in combination with ampicillin, penicillin, gentamicin or vancomycin, on growth of MRSA strains. The antimicrobial activity of BV against MRSA strains was investigated using minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and a time-kill assay. Expression of atl which encodes murein hydrolase, a peptidoglycan-degrading enzyme involved in cell separation, was measured by reverse transcription-polymerase chain reaction. The MICs of BV were 0.085 µg/mL and 0.11 µg/mL against MRSA CCARM 3366 and MRSA CCARM 3708, respectively. The MBC of BV against MRSA 3366 was 0.106 µg/mL and that against MRSA 3708 was 0.14 µg/mL. The bactericidal activity of BV corresponded to a decrease of at least 3 log CFU/g cells. The combination of BV with ampicillin or penicillin yielded an inhibitory concentration index ranging from 0.631 to 1.002, indicating a partial and indifferent synergistic effect. Compared to ampicillin or penicillin, both MRSA strains were more susceptible to the combination of BV with gentamicin or vancomycin. The expression of atl gene was increased in MRSA 3366 treated with BV. These results suggest that BV exhibited antibacterial activity and antibiotic-enhancing effects against MRSA strains. The atl gene was increased in MRSA exposed to BV, suggesting that cell division was interrupted. BV warrants further investigation as a natural antimicrobial agent and synergist of antibiotic activity.

Spa Typing of Staphylococcus aureus Strains Isolated From Clinical Specimens of Patients With Nosocomial Infections in Tehran, Iran.

Abstract: Background: The incidence of nosocomial Staphylococcus aureus infection is increasing annually and becoming a true global challenge. The pattern of Staphylococcus aureus protein A (spa) types in different geographic regions is diverse. Objectives: This study determined the prevalence of methicillin-resistant S. aureus and different spa types in S. aureus clinical isolates. Materials and Methods: During a six-month period, 90 S. aureus isolates were recovered from 320 clinical specimens. The in vitro susceptibility of various S. aureus isolates to 16 antibiotic discs was assessed using the Kirby-Bauer disk diffusion method. Molecular typing was carried out with S. aureus protein A typing via polymerase chain reaction. Results: The frequency of methicillin-resistant S. aureus in our study was 88.9%. Twenty-three (25.5%) isolates were positive for panton-valentine leukocidin encoding genes. S. aureus presented a high resistance rate to ampicillin (100%) and penicillin (100%). No resistance was observed to vancomycin, teicoplanin, or linezolid. The rates of resistance to the majority of antibiotics tested varied between 23.3% and 82.2%. The rate of multidrug resistance among these clinical isolates was 93.3%. The 90 S. aureus isolates were classified into five S. aureus protein A types: t037 (33.3%), t030 (22.2%), t790 (16.7%), t969 (11.1%), and t044 (7.7%). Eight (8.9%) isolates were not typable using the S. aureus protein A typing method. Conclusions: We report a high methicillin-resistant S. aureus rate in our hospital. Additionally, t030 and t037 were the predominant spa-types among hospital-associated S. aureus. Our findings emphasize the need for continuous surveillance to prevent the dissemination of multidrug resistance among different S. aureus protein A types in Iran.

Carriage rate and antibiotic susceptibility of coagulase-positive staphylococci isolated from healthy dogs in Victoria, Australia.

Abstract: Background Studies in Australia and elsewhere have shown high levels of antibiotic resistance in coagulase-positive staphylococci in dogs visiting veterinary clinics with pyoderma and related conditions. Although important, such studies tend to overestimate the burden of resistance. The aim of the current study was to investigate the prevalence of coagulase-positive staphylococci in healthy dogs in Central Victoria to assess the level of antibiotic resistance among these isolates. Methods We recruited 117 healthy dogs into the study. Swabs were taken at four sites (ear, mouth, nose, perineum) and staphylococcal species identified and isolated using culture and biochemical techniques. Results Staphylococcus pseudintermedius and S. aureus were recovered from 100 and 17 dogs, respectively; 15 dogs were simultaneously co-colonised with both organisms. The mouth and perineum were the most sensitive sites for recovery of these organisms. The most commonly encountered resistances were penicillin (95.2% and 72.4% in S. aureus and S. pseudintermedius, respectively) and doxycycline/tetracycline (19.7% in S. pseudintermedius). No methicillin-resistant S. aureus were recovered, but two phenotypically methicillin-resistant S. pseudintermedius (MRSP) isolates were recovered, although only one was PCR-positive for the mecA gene. Notably the MRSP isolate was multidrug resistant, as it also exhibited resistance to mupirocin and erythromycin. Conclusion With the exception of penicillin, doxycycline and tetracycline, the level of resistance to the antimicrobial agents tested was minimal. Prudent antibiotic use in treating companion animals with skin infections will reduce the selection of MRSP and other multidrug-resistant bacteria.

Community Acquired Enterococcal Urinary Tract Infections and Antibiotic Resistance Profile in North India.

Abstract: Background: Urinary tract infections (UTIs) remain a major problem both in hospitalized and outdoor patients. Multidrug-resistant enterococci are emerging as a major nosocomial pathogen with increasing frequency. However, the incidence of community-acquired enterococcal infections and species prevalent in India is not thoroughly investigated. Objectives: This study aims to estimate the burden of community-acquired UTIs seen at a tertiary care hospital and to identify the Enterococcus species isolated from these patients. The study also aims to determine the antibiotic susceptibility pattern with reference to high-level aminoglycosides and vancomycin. Materials and Methods: Semi-quantitative cultures from a total of 22,810 urine samples obtained from patients seen at various Outpatient Departments were analyzed. From them 115 nonduplicate isolates of enterococci were obtained as significant pure growth (>105 cfu/ml) and speciated. Antibiotic susceptibility was performed by Kirby–Bauer disc diffusion method. Vancomycin resistance screening was performed by the vancomycin screen agar method recommended by Clinical and Laboratory Standards Institute and confirmed by determination of minimum inhibitory concentration by agar dilution method. Results: Of 115 enterococcal isolates, 61 were identified as Enterococcus faecalis, 42 as Enterococcus faecium, 3 each as Enterococcus dispar, and Enterococcus pseudoavium. High-level gentamicin resistance (HLGR) was higher in E. faecium (47.6%) than E. faecalis (32.7%) and HLSR also showed the same pattern with 47.6% and 27.9% resistance, respectively. Vancomycin resistant enterococci accounted for 11.3% of the isolates, and out of them 53.8% were E. faecium by agar dilution method. Conclusion: High rate of resistance to antibiotics of penicillin group and aminoglycosides was observed in our tertiary care hospital even in community acquired UTIs. Hence, there is an urgent need for more rational and restricted use of antimicrobials.

Antimicrobial resistance genes in Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida isolated from Australian pigs.

Abstract: Objective To identify genes associated with the observed antimicrobial resistance in Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida isolated from Australian pigs. Design Isolates with known phenotypic resistance to β-lactams, macrolides and tetracycline were screened for the presence of antimicrobial resistance genes. Procedure A total of 68 A. pleuropneumoniae, 62 H. parasuis and 20 P. multocida isolates exhibiting phenotypic antimicrobial resistance (A. pleuropneumoniae and P. multocida) or elevated minimal inhibitory concentrations (MICs) (H. parasuis) to any of the following antimicrobial agents − ampicillin, erythromycin, penicillin, tetracycline, tilmicosin and tulathromycin − were screened for a total of 19 associated antimicrobial resistance genes (ARGs) by PCR. Results The gene bla ROB-1 was found in all ampicillin- and penicillin-resistant isolates, but none harboured the bla TEM-1 gene. The tetB gene was found in 76% (74/97) of tetracycline-resistant isolates, 49/53 A. pleuropneumoniae, 17/30 H. parasuis and 8/14 P. multocida. One A. pleuropneumoniae isolate harboured the tetH gene, but none of the 97 isolates had tetA, tetC, tetD, tetE, tetL, tetM or tetO. A total of 92 isolates were screened for the presence of macrolide resistance genes. None was found to have ermA, ermB, ermC, erm42, mphE, mefA, msrA or msrE. Conclusion The current study has provided a genetic explanation for the resistance or elevated MIC of the majority of isolates of Australian porcine respiratory pathogens to ampicillin, penicillin and tetracycline. However, the macrolide resistance observed by phenotypic testing remains genetically unexplained and further studies are required.