Concentrations of phenoxymethylpenicillin and cefadroxil in tonsillar tissue and tonsillar surface fluid

Next-Generation Digital Biomarkers for Tuberculosis and Antibiotic Stewardship: Perspective on Novel Molecular Digital Biomarkers in Sweat, Saliva, and Exhaled Breath

The internet of health care things enables a remote connection between health care professionals and patients wearing smart biosensors. Wearable smart devices are potentially affordable, sensitive, specific, user-friendly, rapid, robust, lab-independent, and deliverable to the end user for point-of-care testing. The datasets derived from these devices are known as digital biomarkers. They represent a novel patient-centered approach to collecting longitudinal, context-derived health insights. Adding automated, analytical smartphone applications will enable their use in high-, middle-, and low-income countries. So far, digital biomarkers have been focused primarily on accelerometer data and heart rate due to well-established sensors originating from the consumer market. Novel emerging smart biosensors will detect biomarkers (or compounds) independent of a lab and noninvasively in sweat, saliva, and exhaled breath. These molecular digital biomarkers are a promising novel approach to reduce the burden from 2 major infectious diseases with urgent unmet needs: tuberculosis and infections with multidrug resistant pathogens. Active tuberculosis (aTbc) is one of the deadliest diseases from an infectious agent. However, a simple and reliable test for its detection is still missing. Furthermore, inappropriate antimicrobial use leads to the development of antimicrobial resistance, which is associated with high mortality and health care costs. From this perspective, we discuss the innovative approach of a noninvasive and lab-independent collection of novel biomarkers to detect aTbc, which at the same time may additionally serve as a scalable therapeutic drug monitoring approach for antibiotics. These molecular digital biomarkers are next-generation digital biomarkers and have the potential to shape the future of infectious diseases.

Presence, distribution and molecular epidemiology of multi-drug-resistant Gram-negative bacilli from medical personnel of intensive care units in Tianjin, China, 2007-2015

BACKGROUND

Multi-drug-resistant Gram-negative bacteria (MDRGNB) have become an important cause of nosocomial infection in intensive care units (ICUs).

AIMS

To investigate the molecular epidemiology of MDRGNB isolated from medical personnel (MP) and non-medical personnel (NMP) at 69 ICUs in Tianjin, China.

METHODS

From April 2007 to October 2015, 2636 nasal and hand swab samples from 1185 MP and 133 NMP were cultured for GNB (including MDRGNB), meticillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The susceptibilities of GNB to 14 antimicrobial agents were determined, and 80 MDRGNB were characterized using pulsed-field gel electrophoresis (PFGE) and dendrogram analysis.

FINDINGS

In total, 301 GNB were identified in 269 MP, including 109 MDRGNB isolates in 104 MP. Forty-two GNB were isolated from 39 NMP, which included 20 NMP with MDRGNB. Overall, 8.8% of MP were colonized with MDRGNB, which greatly exceeded colonization rates with MRSA (0.9%) and VRE (0.1%). Three pairs of Klebsiella pneumoniae and one pair of Enterobacter aerogenes were indistinguishable from each other, but the majority of isolate tests had distinct PFGE profiles.

CONCLUSIONS

The prevalence of MDRGNB was high among ICU MP in Tianjin, and greatly exceeded that of VRE and MRSA. There was no difference in the rates of nasal carriage of MDRGNB between MP and NMP, but NMP were significantly more likely to have hand colonization with MDRGNB. PFGE profiles showed that there was only limited sharing of strains of MDR E. aerogenes and K. pneumoniae between personnel.

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

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.

Unravelling the ecology of antibiotic resistant bacteria in the nasopharynx

To study the dynamics and diversity of pneumococcal carriage and antibiotic resistance, a more thorough and systematic approach has been employed compared with routine surveillance of serotype and anti-biotic resistance. Up to ten pneumococcal isolates from pernasal (nose) and oropharyngeal (throat) sites are isolated and characterised. Our carriage studies have revealed a diverse community of pneumococci with multiple strains colonising the nasopharynx of children. In Tanzanian children less than 6 years of age, up to six serotypes and up to six different antibiotic sensitivities (as distinguished by at least a fourfold difference in the minimum inhibitory concentration) have been found. Serotyping by the Quelling reaction is prone to inaccuracy and requires expensive serological reagents. To improve the accuracy and reduce the costs, an alternative capsular typing DNA-based method has been developed. This chapter will describe the methods we have employed with emphasis on the capsular typing method.

Penicillin V, loracarbef and clindamycin in tonsillar surface fluid during acute group A streptococcal pharyngotonsillitis

A previously healthy 37-y-old male presented with community-acquired pneumonia and extensive upper limb deep vein thrombosis. The diagnosis of Legionella pneumonia was made based on a positive direct immunofluorescence of the bronchial wash. An extensive investigation for hypercoagulable states was negative. The possible association between Legionella infection and deep vein thrombosis is highlighted.

Frequency of symptomatic relapses of group A beta-hemolytic streptococcal tonsillopharyngitis in children from 4 pediatric practices following penicillin, amoxicillin, and cephalosporin antibiotic treatment

The objective was to determine the frequency of early symptomatic relapses following antibiotic treatment for group A beta-hemolytic streptococcal (GABHS) tonsillopharyngitis in children from Rochester, New York; Houston, Texas; Spokane, Washington; and Los Angeles, California (2004--2006). The study included 4278 patients. The proportion with a bacteriologic relapse of GABHS tonsillopharyngitis within 1 to 5 days of completing a 10-day treatment course was 8% (penicillin and bicillin), 6% (amoxicillin), 2% (first-generation cephalosporin), and 1% (second-generation and third-generation cephalosporin; P = .0001); symptomatic relapses occurred within 6 to 20 days after completion of therapy in 16%, 14%, 9%, and 7% of cases (P = .0001). Cases from New York and Washington had higher penicillin or amoxicillin failure rates than cases from Texas and California. The frequency of symptomatic relapses of GABHS tonsillopharyngitis, therefore, differs according to the antibiotic treatment selected; the trend for such relapses being penicillin or amoxicillin > cephalosporins although geographic differences may occur.

Bacterial eradication rates with shortened courses of 2nd- and 3rd-generation cephalosporins versus 10 days of penicillin for treatment of group A streptococcal tonsillopharyngitis in adults

In a meta-analysis of 5 randomized controlled trials involving 1030 adults, the likelihood of bacteriologic eradication in the treatment of group A beta-hemolytic streptococcal (GAS) tonsillopharyngitis with 5 days of select cephalosporins (cefpodoxime, cefuroxime, cefotiam, and cefdinir) was noninferior to 10 days of penicillin (odds ratio, 1.46; 95% confidence interval, 0.96-2.22, P = 0.08).

Meta-analysis of Cephalosporins versus Penicillin for Treatment of Group A Streptococcal Tonsillopharyngitis in Adults

We conducted a meta-analysis of 9 randomized controlled trials (involving 2113 patients) comparing cephalosporins with penicillin for treatment of group A beta -hemolytic streptococcal (GABHS) tonsillopharyngitis in adults. The summary odds ratio (OR) for bacteriologic cure rate significantly favored cephalosporins, compared with penicillin (OR,1.83; 95% confidence interval [CI], 1.37-2.44); the bacteriologic failure rate was nearly 2 times higher for penicillin therapy than it was for cephalosporin therapy (P=.00004). The summary OR for clinical cure rate was 2.29 (95% CI, 1.61-3.28), significantly favoring cephalosporins (P<.00001). Sensitivity analyses for bacterial cure significantly favored cephalosporins over penicillin in trials that were double-blinded and of high quality, trials that had a well-defined clinical status, trials that performed GABHS serotyping, trials that eliminated carriers from analysis, and trials that had a test-of-cure culture performed 3-14 days after treatment. This meta-analysis indicates that the likelihood of bacteriologic and clinical failure in the treatment of GABHS tonsillopharyngitis is 2 times higher for oral penicillin than for oral cephalosporins.

Meta-analysis of cephalosporin versus penicillin treatment of group A streptococcal tonsillopharyngitis in children

OBJECTIVE

To conduct a meta-analysis of randomized, controlled trials of cephalosporin versus penicillin treatment of group A beta-hemolytic streptococcal (GABHS) tonsillopharyngitis in children.

METHODOLOGY

Medline, Embase, reference lists, and abstract searches were conducted to identify randomized, controlled trials of cephalosporin versus penicillin treatment of GABHS tonsillopharyngitis in children. Trials were included if they met the following criteria: patients <18 years old, bacteriologic confirmation of GABHS tonsillopharyngitis, random assignment to antibiotic therapy of an orally administered cephalosporin or penicillin for 10 days of treatment, and assessment of bacteriologic outcome using a throat culture after therapy. Primary outcomes of interest were bacteriologic and clinical cure rates. Sensitivity analyses were performed to assess the impact of careful clinical illness descriptions, compliance monitoring, GABHS serotyping, exclusion of GABHS carriers, and timing of the test-of-cure visit.

RESULTS

Thirty-five trials involving 7125 patients were included in the meta-analysis. The overall summary odds ratio (OR) for the bacteriologic cure rate significantly favored cephalosporins compared with penicillin (OR: 3.02; 95% confidence interval [CI]: 2.49-3.67, with the individual cephalosporins [cephalexin, cefadroxil, cefuroxime, cefpodoxime, cefprozil, cefixime, ceftibuten, and cefdinir] showing superior bacteriologic cure rates). The overall summary OR for clinical cure rate was 2.33 (95% CI: 1.84-2.97), significantly favoring the same individual cephalosporins. There was a trend for diminishing bacterial cure with penicillin over time, comparing the trials published in the 1970s, 1980s, and 1990s. Sensitivity analyses for bacterial cure significantly favored cephalosporin treatment over penicillin treatment when trials were grouped as double-blind (OR: 2.31; 95% CI: 1.39-3.85), high-quality (OR: 2.50; 95% CI: 1.85-3.36) trials with well-defined clinical status (OR: 2.12; 95% CI: 1.54-2.90), with detailed compliance monitoring (OR: 2.85; 95% CI: 2.33-3.47), with GABHS serotyping (OR: 3.10; 95% CI: 2.42-3.98), with carriers eliminated (OR: 2.51; 95% CI: 1.55-4.08), and with test of cure 3 to 14 days posttreatment (OR: 3.53; 95% CI: 2.75-4.54). Analysis of comparative bacteriologic cure rates for the 3 generations of cephalosporins did not show a difference.

CONCLUSIONS

This meta-analysis indicates that the likelihood of bacteriologic and clinical failure of GABHS tonsillopharyngitis is significantly less if an oral cephalosporin is prescribed, compared with oral penicillin.

Intracellular reservoir of Streptococcus pyogenes in vivo: a possible explanation for recurrent pharyngotonsillitis

Numerous theories have been presented that attempt to explain the frequent recurrences of pharyngotonsillitis caused by Streptococcus pyogenes; these recurrences occur after seemingly adequate antibiotic treatment. We previously have demonstrated that Spyogenes can survive for up to 7 days intracellularly in immortalized human respiratory epithelial cells grown in an antibiotic supplemented medium. Viable S pyogenes were externalized and established an extracellular infection, whenever the extracellular antibiotic was removed. We have investigated the presence of intracellular S pyogenes in two in vivo studies using respiratory epithelial cells collected from patients with tonsillitis and the tonsils of asymptomatic carriers. Electron microscopy and immunohistochemistry demonstrated intracellular S pyogenes in pharyngeal epithelial cells in 13 of 14 patients with tonsillitis (93%). Furthermore, intracellular S pyogenes were found in macrophage-like cells in eight (73%) and in epithelial cells in four (36%) tonsils from 11 asymptomatic S pyogenes carriers. These in vivo data strongly support the hypothesis that intracellular S pyogenes can constitute a reservoir of bacteria with the potential to cause reinfections.

Characterization of peripheral-compartment kinetics of antibiotics by in vivo microdialysis in humans

The calculation of pharmacokinetic/pharmacodynamic surrogates from concentrations in serum has been shown to yield important information for the evaluation of antibiotic regimens. Calculations based on concentrations in serum, however, may not necessarily be appropriate for peripheral-compartment infections. The aim of the present study was to apply the microdialysis technique for the study of the peripheral-compartment pharmacokinetics of select antibiotics in humans. Microdialysis probes were inserted into the skeletal muscle and adipose tissue of healthy volunteers and into inflamed and noninflamed dermis of patients with cellulitis. Thereafter, volunteers received either cefodizime (2,000 mg as an intravenous bolus; n = 6), cefpirome (2,000 mg as an intravenous bolus; n = 6), fleroxacin (400 mg orally n = 6), or dirithromycin (250 mg orally; n = 4); the patients received phenoxymethylpenicillin (4.5 x 10(6) U orally; n = 3). Complete concentration-versus-time profiles for serum and tissues could be obtained for all compounds. Major pharmacokinetic parameters (elimination half-life, peak concentration in serum, time to peak concentration, area under the concentration-time curve [AUC], and AUC/MIC ratio) were calculated for tissues. For cefodizime and cefpirome, the AUCtissue/AUCserum ratios were 0.12 to 0.35 and 1.20 to 1.79, respectively. The AUCtissue/AUCserum ratios were 0.34 to 0.38 for fleroxacin and 0.42 to 0.49 for dirithromycin. There was no visible difference in the time course of phenoxymethylpenicillin in inflamed and noninflamed dermis. We demonstrated, by means of microdialysis, that the concept of pharmacokinetic/pharmacodynamic surrogate markers for evaluation of antibiotic regimens originally developed for serum pharmacokinetics can be extended to peripheral-tissue pharmacokinetics. This novel information may be useful for the rational development of dosage schedules and may improve predictions regarding therapeutic outcome.

Randomized evaluation of benzathine penicillin V twice daily versus potassium penicillin V three times daily in the treatment of group A streptococcal pharyngitis. Pharyngitis Study Group

In a randomized, prospective, multicenter study the clinical and bacteriological efficacies of three dosage schedules with two different salts of oral penicillin V suspensions (regimen 1: potassium salt of penicillin V, 50,000 U/kg of body weight per day in three divided doses; regimen 2: benzathine salt of penicillin V, 50,000 U/kg of body weight per day in two divided doses; and regimen 3: benzathine salt of penicillin V, 100,000 U/kg of body weight in two divided doses) for the treatment of streptococcal pharyngitis were evaluated. Children with clinical signs of acute pharyngitis and a positive throat culture for group A beta-hemolytic streptococci (GABHS) were eligible. There was no difference between the treatment groups with respect to the overall clinical success rate. Eradication of the original serotype of GABHS from throat cultures was achieved in 87.1% (regimen 1), 85.5% (regimen 2) and 87.7% (regimen 3) of patients. The incidence of potential drug-related adverse events was significantly higher in patients treated with regimen 3. The results of this and earlier studies strongly suggest that oral penicillin given twice daily should be the recommended treatment for the initial treatment of pharyngitis due to GABHS. Doubling the total daily dose is not beneficial in the usual clinical setting. Because of its favorable pharmacokinetics, the benzathine salt of penicillin V appears to be well suited for a twice-a-day dosage schedule.

Clindamycin in persisting streptococcal pharyngotonsillitis after penicillin treatment

239 patients with streptococcal pharyngotonsillitis completed treatment with phenoxymethyl penicillin 12.5 mg per kg body weight b.i.d. for 10 days. At examination after completing therapy, throat specimens from 53 patients (22%) yielded growth of group A streptococci of the same. T-type as the initial culture (bacterial treatment failure). 20 of these 53 (38%) had symptoms and signs of tonsillitis (clinical and bacterial treatment failure). 48 of the patients with bacterial failure were randomly allocated to phenoxymethyl penicillin or clindamycin in an open design; 22 of them received a second course of phenoxymethyl penicillin for 10 days and 26 were given clindamycin, 6.5 mg per kg body weight b.i.d. (children) or 300 mg t.i.d. (adults) for 10 days. After completing their treatment, 14 of 22 patients (64%) given phenoxymethyl penicillin harboured the same T-type as in the previous two cultures, while group A streptococci were not recovered from any of the 26 patients receiving clindamycin. In patients with clinical failure after phenoxymethyl penicillin treatment, a new course with this drug is not motivated. In that situation clindamycin seems to be an efficient choice.

Penetration of penicillin V to tonsillar surface fluid in healthy individuals and in patients with acute tonsillitis

In the treatment of group A streptococcal tonsillitis, as the bacteria are located on the epithelial surface, an important determinant of outcome is the concentration of penicillin in extracellular tonsillar surface fluid. Accordingly, we investigated the concentration of penicillin in serum, and penetration to tonsillar surface fluid and saliva in nine patients with acute group A streptococcal tonsillitis and in nine healthy controls. Among the healthy subjects, despite high serum penicillin concentrations (mean, 2.04 micrograms/ml), there was no penetration to tonsillar surface fluid or to saliva, whereas erythromycin penetrated to tonsillar surface fluid in 3/6 cases. Of the nine patients with acute tonsillitis, on the first day of treatment eight manifested high concentrations of penicillin in tonsillar surface fluid (mean, 0.34 micrograms/ml--i.e. well above the minimal inhibitory concentration (MIC) for group A streptococci), but penetration to saliva was found in only two patients. On the tenth day of treatment, penicillin was not present in the saliva of any of the patients and was present in the tonsillar surface fluid of only one. The results suggest that measurable concentrations of penicillin in tonsillar surface fluid can only be obtained in the presence of inflammation with fluid exudation through the tonsillar epithelium.

Concentration of phenoxymethylpenicillin in tonsillar tissue

Seventeen patients underwent tonsillectomy 55-120 min after receiving oral phenoxymethylpenicillin 12.5 mg/kg bodyweight. The penicillin concentration in serum and tonsillar tissue in each patient was determined by a microbial assay. In 9 patients with tonsillar hyperplasia, but with no prior history of tonsillitis, the mean penicillin concentration in serum and in tonsillar tissue was 5.0 mg.l-1 and 1.32 mg.g-1, respectively, and in 8 patients with manifest tonsillitis the corresponding values were 3.01 mg.l-1 and 0.67 mg.g-1. It appears that the penicillin concentration in tonsillar tissue is about 1/5 to 1/4 of that in serum, regardless of whether the tonsils are inflamed or hypertrophied.

Five versus ten days treatment of group A streptococcal pharyngotonsillitis: a randomized controlled clinical trial with phenoxymethylpenicillin and cefadroxil

216 patients aged greater than or equal to 7 years with febrile group A streptococcal pharyngotonsillitis were randomly assigned to 3 treatment groups receiving either phenoxymethylpenicillin for 5 days followed by placebo for 5 days, phenoxymethylpenicillin for 10 days, or cefadroxil for 10 days. 209 patients completed treatment, 70 subjects in each phenoxymethylpenicillin group and 69 in the cefadroxil group. Within 1 week after completion of the antibiotic treatment significantly more recurrences with the same T-type as the initial streptococcal strain occurred in the 5-day treatment group (27%) as compared with the two 10-day groups (6% and 3%, respectively). The cumulative rate of recurrences (irrespective of T-type) within 2 months from the start of therapy was 55% among patients treated with phenoxymethylpenicillin for 5 days, 24% among those treated for 10 days with this drug and 19% among patients receiving cefadroxil. Obviously, one important factor to avoid recurrence of group A streptococcal pharyngotonsillitis is the length of antibiotic treatment and, in our opinion, it is not advisable to change the current recommendation of 10 days treatment.