1
|
Andretta E, Longo R, Balladelli M, Sgarabotto C, Sgarabotto D. Intravesical Gentamicin: An Option for Therapy and Prophylaxis against Recurrent UTIs and Resistant Bacteria in Neurogenic Bladder Patients on Intermittent Catheterization. Antibiotics (Basel) 2022; 11:1335. [PMID: 36289993 PMCID: PMC9598998 DOI: 10.3390/antibiotics11101335] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/14/2022] [Accepted: 08/10/2022] [Indexed: 08/01/2023] Open
Abstract
This is a retrospective study of our experience with Gentamicin intravesical instillation as therapy and prophylaxis in patients with lower urinary tract infections (UTIs) undergoing clean intermittent catheterization because of a neurogenic bladder. It is an alternative therapy when all other systemic treatments have failed as it is still an off-label prescription.
Collapse
Affiliation(s)
| | | | | | | | - Dino Sgarabotto
- Abano Infectious Diseases Outpatient Clinic, 35031 Padova, Italy
| |
Collapse
|
2
|
A Major Facilitator Superfamily (MFS) Efflux Pump, SCO4121, from Streptomyces coelicolor with Roles in Multidrug Resistance and Oxidative Stress Tolerance and Its Regulation by a MarR Regulator. Appl Environ Microbiol 2021; 87:AEM.02238-20. [PMID: 33483304 DOI: 10.1128/aem.02238-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
Overexpression of efflux pumps is one of the major determinants of resistance in bacteria. Streptomyces species harbor a large array of efflux pumps that are transcriptionally silenced under laboratory conditions. However, their dissemination results in multidrug resistance in different clinical pathogens. In this study, we have identified an efflux pump from Streptomyces coelicolor, SCO4121, belonging to the major facilitator superfamily (MFS) family of transporters and characterized its role in antibiotic resistance. SCO4121 provided resistance to multiple dissimilar drugs upon overexpression in both native and heterologous hosts. Further, deletion of SCO4121 resulted in increased sensitivity toward ciprofloxacin and chloramphenicol, suggesting the pump to be a major transporter of these substrates. Apart from providing multidrug resistance, SCO4121 imparted increased tolerance against the strong oxidant HOCl. In wild-type Streptomyces coelicolor cells, these drugs were found to transcriptionally regulate the pump in a concentration-dependent manner. Additionally, we identified SCO4122, a MarR regulator that positively regulates SCO4121 in response to various drugs and the oxidant HOCl. Thus, through these studies we present the multiple roles of SCO4121 in S. coelicolor and highlight the intricate mechanisms via which it is regulated in response to antibiotics and oxidative stress.IMPORTANCE One of the key mechanisms of drug resistance in bacteria is overexpression of efflux pumps. Streptomyces species are a reservoir of a large number of efflux pumps, potentially to provide resistance to both endogenous and nonendogenous antibiotics. While many of these pumps are not expressed under standard laboratory conditions, they result in resistance to multiple drugs when spread to other bacterial pathogens through horizontal gene transfer. In this study, we have identified a widely conserved efflux pump SCO4121 from Streptomyces coelicolor with roles in both multidrug resistance and oxidative stress tolerance. We also report the presence of an adjacent MarR regulator, SCO4122, which positively regulates SCO4121 in the presence of diverse substrates in a redox-responsive manner. This study highlights that soil bacteria such as Streptomyces can reveal novel mechanisms of antibiotic resistance that may potentially emerge in clinically important bacteria.
Collapse
|
3
|
Clark JA, Burgess DS. Plazomicin: a new aminoglycoside in the fight against antimicrobial resistance. Ther Adv Infect Dis 2020; 7:2049936120952604. [PMID: 32953108 PMCID: PMC7475792 DOI: 10.1177/2049936120952604] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Objective To review the mechanism of action, mechanisms of resistance, in vitro activity, pharmacokinetics, pharmacodynamics, and clinical data for a novel aminoglycoside. Data sources A PubMed search was performed from January 2006 to August 2019 using the following search terms: plazomicin and ACHN-490. Another search was conducted on clinicaltrials.gov for published clinical data. References from selected studies were also used to find additional literature. Study selection and data extraction All English-language studies presenting original research (in vitro, in vivo, pharmacokinetic, and clinical) were evaluated. Data synthesis Plazomicin has in vitro activity against several multi-drug-resistant organisms, including carbapenem-resistant Enterobacteriaceae. It was Food and Drug Administration (FDA) approved to treat complicated urinary tract infections (cUTIs), including acute pyelonephritis, following phase II and III trials compared with levofloxacin and meropenem, respectively. Despite the FDA Black Box Warning for aminoglycoside class effects (nephrotoxicity, ototoxicity, neuromuscular blockade, and pregnancy risk), it exhibited a favorable safety profile with the most common adverse effects being decreased renal function (3.7%), diarrhea (2.3%), hypertension (2.3%), headache (1.3%), nausea (1.3%), vomiting (1.3%), and hypotension (1.0%) in the largest in-human trial. Relevance to patient care and clinical practice Plazomicin will likely be used in the treatment of multi-drug-resistant cUTIs or in combination to treat serious carbapenem-resistant Enterobacteriaceae infections. Conclusions Plazomicin appears poised to help fill the need for new agents to treat infections caused by multi-drug-resistant Enterobacteriaceae.
Collapse
Affiliation(s)
- Justin A Clark
- University of Kentucky College of Pharmacy, Lexington, KY, USA
| | - David S Burgess
- University of Kentucky College of Pharmacy, 292K TODD Building, 789 South Limestone St., Lexington, KY 40536-0596, USA
| |
Collapse
|
4
|
Oda K, Fujii S, Yamamoto T, Mayumi T, Takesue Y. Evaluation of once-daily dosing and target concentrations in therapeutic drug monitoring for arbekacin: A meta-analysis. J Infect Chemother 2020; 27:26-31. [PMID: 32828677 DOI: 10.1016/j.jiac.2020.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/17/2020] [Accepted: 08/03/2020] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Arbekacin is the first aminoglycoside antibacterial agent approved for treating methicillin-resistant Staphylococcus aureus infection in Japan. Although therapeutic drug monitoring (TDM) is recommended during arbekacin treatment, little evidence for the target exposure and once-daily dosing has been reported. This study aimed to clarify the target peak/trough concentrations and the effectiveness of once-daily dosing of arbekacin against nephrotoxicity or treatment failure via meta-analysis. METHODS A literature search was performed using MEDLINE, Cochrane Library, and Ichushi-Web. RESULTS Nine observational cohort studies met the inclusion criteria. A peak arbekacin concentration of ≥15-16 μg/mL did not exhibit a statistically significant lower risk of treatment failure (risk ratio [RR] = 0.61, 95% confidence interval [CI] = 0.30-1.24). A trough arbekacin concentration of <2 μg/mL resulted in a significantly lower risk of nephrotoxicity (RR = 0.30, 95% CI = 0.15-0.61). Once-daily dosing significantly reduced the risk of treatment failure (RR = 0.61, 95% CI = 0.39-0.97) but not nephrotoxicity (RR = 0.54, 95% CI = 0.16-1.75). CONCLUSIONS Once-daily dosing can improve the therapeutic efficacy of arbekacin, and a trough arbekacin concentration of <2 μg/mL can reduce the risk of nephrotoxicity. A peak arbekacin concentration of ≥15-16 μg/mL did not exhibit the significant lower risk of treatment failure. Additional clinical trials are required to confirm these findings.
Collapse
Affiliation(s)
- Kazutaka Oda
- Department of Pharmacy, Kumamoto University Hospital, 1-1-1, Honjo, Chuo-ku, Kumamoto, 860-8556, Japan; Department of Infection Control, Kumamoto University Hospital, 1-1-1, Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
| | - Satoshi Fujii
- Department of Pharmacy, Sapporo Medical University Hospital, S1 W16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.
| | - Takehito Yamamoto
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
| | - Toshihiko Mayumi
- Department of Emergency Medicine, School of Medicine, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku Kitakyushu, Fukuoka, 807-8555, Japan.
| | - Yoshio Takesue
- Department of Infection Control and Prevention, Hyogo College of Medicine, 1-1, Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan.
| |
Collapse
|
5
|
Cies JJ, Habib T, Bains V, Young M, Menkiti OR. Population Pharmacokinetics of Gentamicin in Neonates with Hypoxemic-Ischemic Encephalopathy Receiving Controlled Hypothermia. Pharmacotherapy 2018; 38:1120-1129. [PMID: 30300445 DOI: 10.1002/phar.2186] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Identify population pharmacokinetics and pharmacodynamic target attainment of gentamicin in neonates with hypoxic-ischemic encephalopathy (HIE) undergoing controlled hypothermia (CH). DESIGN Prospective open-label pharmacokinetic study. Gentamicin concentrations were modeled and dosing regimens simulated for a 5000-patient neonatal population with HIE receiving CH using PMetrics, a nonparametric, pharmacometric modeling, and simulation package for R. SETTING A 189-bed children's tertiary care teaching hospital. RESULTS Twelve patients, 5 (42%) females and 7 (58%) males, met inclusion criteria with a median gestation age of 39.9 weeks (interquartile range [IQR] 38.5-40.2 wks) and a median birthweight (BW) of 3.3 kg (IQR 3.1-3.7 kg). Gentamicin concentrations were best described by a two-compartment model with first-order elimination with BW as a covariate on volume of distribution (Vd). The mean total body population clearance (CL) was 2.2 ± 0.7 ml/minute/kg, and the volume of the central compartment was 0.44 ± 0.06 L/kg. The R2 , bias, and precision for the observed versus population predicted model were 0.917, 1.15, and 10.9 μg/ml; the R2 , bias, and precision for the observed versus individual predicted model were 0.982, -0.132, and 0.932 μg/ml, respectively. The calculated mean population estimate for the total Vd was 0.96 ± 0.4 L/kg. The dosing regimen that most consistently produced a maximum concentration (Cmax ) in the range of 10-12 mg/L with a minimum concentration (Cmin ) level less than 2 mg/L was 5 mg/kg/dose given every 36 hours. CONCLUSION These data suggest the population pharmacokinetics of gentamicin in neonates with HIE receiving CH have an increase in gentamicin CL and are different from previous reports in neonates with HIE not receiving CH and/or neonates without HIE. This analysis suggests a dosing regimen of 5 mg/kg/dose every 36 hours results in a gentamicin Cmax within the range of 10-12 mg/L with a Cmin lower than 2 mg/L, which is appropriate for treating susceptible gram-negative organisms with minimum inhibitory concentrations of 1 mg/L or lower.
Collapse
Affiliation(s)
- Jeffrey J Cies
- The Center for Pediatric Pharmacotherapy, LLC, Pottstown, Pennsylvania.,St. Christopher's Hospital for Children, Philadelphia, Pennsylvania.,Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Thomas Habib
- St. Christopher's Hospital for Children, Philadelphia, Pennsylvania.,Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Vidhy Bains
- St. Christopher's Hospital for Children, Philadelphia, Pennsylvania
| | - Megan Young
- St. Christopher's Hospital for Children, Philadelphia, Pennsylvania
| | - Ogechukwu R Menkiti
- St. Christopher's Hospital for Children, Philadelphia, Pennsylvania.,Drexel University College of Medicine, Philadelphia, Pennsylvania
| |
Collapse
|
6
|
Spencer S, Ipema H, Hartke P, Krueger C, Rodriguez R, Gross AE, Gabay M. Intravenous Push Administration of Antibiotics: Literature and Considerations. Hosp Pharm 2018; 53:157-169. [PMID: 30147136 PMCID: PMC6102793 DOI: 10.1177/0018578718760257] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Intravenous (IV) push administration can provide clinical and practical advantages over longer IV infusions in multiple clinical scenarios, including in the emergency department, in fluid-restricted patients, and when supplies of diluents are limited. In these settings, conversion to IV push administration may provide a solution. This review compiles available data on IV push administration of antibiotics in adults, including preparation, stability, and administration instructions. Prescribing information, multiple tertiary drug resources, and primary literature were consulted to compile relevant data. Several antibiotics are Food and Drug Administration-approved for IV push administration, including many beta-lactams. In addition, cefepime, ceftriaxone, ertapenem, gentamicin, and tobramycin have primary literature data to support IV push administration. While amikacin, ciprofloxacin, imipenem/cilastatin, and metronidazole have limited primary literature data on IV push administration, available data do not support that route. In addition, a discussion on practical considerations, such as IV push best practices and pharmacodynamic considerations, is provided.
Collapse
Affiliation(s)
| | - Heather Ipema
- College of Pharmacy, University of Illinois at
Chicago, USA
| | | | | | - Ryan Rodriguez
- College of Pharmacy, University of Illinois at
Chicago, USA
| | - Alan E. Gross
- College of Pharmacy, University of Illinois at
Chicago, USA
| | - Michael Gabay
- College of Pharmacy, University of Illinois at
Chicago, USA
| |
Collapse
|
7
|
Population Pharmacokinetics and Dosing Considerations for Gentamicin in Newborns with Suspected or Proven Sepsis Caused by Gram-Negative Bacteria. Antimicrob Agents Chemother 2016; 61:AAC.01304-16. [PMID: 27795373 DOI: 10.1128/aac.01304-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/09/2016] [Indexed: 12/13/2022] Open
Abstract
The aim of this study was to describe the population pharmacokinetics (PK) of gentamicin in neonates with suspected or proven Gram-negative sepsis and determine the optimal dosage regimen in relation to the bacterial MICs found in this population. Data were prospectively collected between October 2012 and January 2013 in the Neonatal Intensive Care Unit (NICU) at the Academic Medical Center (AMC), Amsterdam, The Netherlands. A single nonlinear mixed-effects regression analysis (NONMEM) was performed to describe the population PK of gentamicin. Dosage regimens based upon gestational age (GA) were generated using Monte Carlo simulations with the final model. Target values were based on the MIC distribution in our patient population. In total, 136 gentamicin concentrations from 65 (pre)term neonates were included. The PK was best described by an allometric 2-compartment model with postmenstrual age (PMA) as a covariate on clearance (Cl). The MIC distribution (median, 0.75 [range, 0.5 to 1.5] mg/liter) justified a gentamicin target peak concentration of 8 to 12 mg/liter. This study describes the PK of gentamicin in (pre)term neonates. Dosage regimens of 5 mg/kg of body weight every 48 h, 5 mg/kg every 36 h, and 5 mg/kg every 24 h for patients with GAs of <37 weeks, 37 to 40 weeks, and ≥40 weeks, respectively, are recommended.
Collapse
|
8
|
Bijleveld YA, de Haan TR, van der Lee HJH, Groenendaal F, Dijk PH, van Heijst A, de Jonge RCJ, Dijkman KP, van Straaten HLM, Rijken M, Zonnenberg IA, Cools F, Zecic A, Nuytemans DHGM, van Kaam AH, Mathot RAA. Altered gentamicin pharmacokinetics in term neonates undergoing controlled hypothermia. Br J Clin Pharmacol 2016; 81:1067-77. [PMID: 26763684 PMCID: PMC4876193 DOI: 10.1111/bcp.12883] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 01/05/2016] [Accepted: 01/10/2016] [Indexed: 11/29/2022] Open
Abstract
AIM(S) Little is known about the pharmacokinetic (PK) properties of gentamicin in newborns undergoing controlled hypothermia after suffering from hypoxic−ischaemic encephalopathy due to perinatal asphyxia. This study prospectively evaluates and describes the population PK of gentamicin in these patients METHODS Demographic, clinical and laboratory data of patients included in a multicentre prospective observational cohort study (the ‘PharmaCool Study’) were collected. A non-linear mixed-effects regression analysis (nonmem®) was performed to describe the population PK of gentamicin. The most optimal dosing regimen was evaluated based on simulations of the final model. RESULTS A total of 47 patients receiving gentamicin were included in the analysis. The PK were best described by an allometric two compartment model with gestational age (GA) as a covariate on clearance (CL). During hypothermia the CL of a typical patient (3 kg, GA 40 weeks, 2 days post-natal age (PNA)) was 0.06 l kg−1 h−1 (inter-individual variability (IIV) 26.6%) and volume of distribution of the central compartment (Vc) was 0.46 l kg−1 (IIV 40.8%). CL was constant during hypothermia and rewarming, but increased by 29% after reaching normothermia (>96 h PNA). CONCLUSIONS This study describes the PK of gentamicin in neonates undergoing controlled hypothermia. The 29% higher CL in the normothermic phase compared with the preceding phases suggests a delay in normalization of CL after rewarming has occurred. Based on simulations we recommend an empiric dose of 5 mg kg−1 every 36 h or every 24 h for patients with GA 36–40 weeks and GA 42 weeks, respectively.
Collapse
Affiliation(s)
| | - Timo R de Haan
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam
| | - Hanneke J H van der Lee
- Pediatric Clinical Research Office, Division Woman-Child, Academic Medical Center, University of Amsterdam, Amsterdam
| | - Floris Groenendaal
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht
| | - Peter H Dijk
- Department of Neonatology, University Medical Center Groningen, Groningen
| | - Arno van Heijst
- Department of Neonatology, Radboud University Medical Center, Nijmegen
| | - Rogier C J de Jonge
- Department of Pediatrics, Division of Neonatology, Erasmus MC-Sophia Children's Hospital, Rotterdam
| | - Koen P Dijkman
- Department of Neonatology, Máxima Medical Center Veldhoven, Veldhoven
| | | | - Monique Rijken
- Department of Neonatology, Leiden University Medical Center, Leiden
| | - Inge A Zonnenberg
- Department of Neonatology, VU University Medical Center, Amsterdam, The Netherlands
| | - Filip Cools
- Department of Neonatology, Vrije Universiteit Brussel, Brussels
| | - Alexandra Zecic
- Department of Neonatology, Academic Medical Center, Gent, Belgium
| | | | - Anton H van Kaam
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam
| | - Ron A A Mathot
- Department of Pharmacy, Academic Medical Center, Amsterdam
| |
Collapse
|
9
|
Eschenauer GA, Lam SW, Mueller BA. Dose Timing of Aminoglycosides in Hemodialysis Patients: A Pharmacology View. Semin Dial 2016; 29:204-13. [PMID: 26756428 DOI: 10.1111/sdi.12458] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aminoglycosides for patients undergoing intermittent hemodialysis (IHD) have traditionally been dosed at half the normal dose administered at the end of a hemodialysis session. Several investigations have suggested that administering higher doses preceding or with the initiation of dialysis would more readily optimize pharmacodynamic parameters. However, the selection of an optimal aminoglycoside dosing strategy in patients receiving IHD is complex and requires consideration of numerous factors, precluding a singular approach. By reviewing aminoglycoside pharmacokinetics, pharmacodynamics, risks for toxicity and resistance development, and practical considerations, we derive indication- and setting- specific recommendations. We identify some areas (definitive therapy of gram-negative infections in patients receiving predictable hemodialysis sessions, for example) where dosing preceding or with the initiation of dialysis is optimal and feasible, and others (gram-positive synergy, unstable patients with poor/unpredictable vascular access) where postdialysis dosing remains preferred. Finally, given the dearth of data exploring the pharmacodynamics and clinical outcomes of IHD patients receiving aminoglycoside therapy, we identify several key questions in need of investigation.
Collapse
Affiliation(s)
- Gregory A Eschenauer
- Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, Michigan
| | - Simon W Lam
- Department of Pharmacy, Cleveland Clinic, Cleveland, Ohio
| | - Bruce A Mueller
- Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, Michigan
| |
Collapse
|
10
|
Roberts GW, Harbi GA, Khalessi-Rad M. Immediate Post-Administration Safety of Bolus Gentamicin. JOURNAL OF PHARMACY PRACTICE AND RESEARCH 2012. [DOI: 10.1002/j.2055-2335.2012.tb00170.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
11
|
Pharmacokinetics and safety of single and multiple doses of ACHN-490 injection administered intravenously in healthy subjects. Antimicrob Agents Chemother 2011; 55:5874-80. [PMID: 21911572 DOI: 10.1128/aac.00624-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ACHN-490 is an aminoglycoside with activity against multidrug-resistant pathogens, including those resistant to currently used aminoglycosides. Two randomized, double-blind, placebo-controlled clinical studies investigated the pharmacokinetics (PK), safety, and tolerability of ACHN-490 injection in healthy subjects. Study 1 used a parallel-group design with escalating single (SD) and multiple doses (MD). Study 2 explored a longer duration of the highest dose tolerated in the first study. Subjects were randomly assigned to receive either ACHN-490 injection or a placebo administered by a 10-min intravenous infusion. Study 1 enrolled 39 subjects (30 active and 9 placebo) and consisted of a single dose of 1 mg/kg body weight followed by ascending SD and MD cohorts of 4, 7, 11, and 15 mg/kg for 10, 10, 5, and 3 days, respectively. Study 2 enrolled 8 subjects (6 active and 2 placebo) who received 15 mg/kg for 5 days. Safety was assessed from adverse event (AE) reporting, standard clinical laboratory procedures, and testing for renal, cochlear, and vestibular function. ACHN-490 exhibited linear and dose-proportional PK, with agreement between the studies for PK parameters assessed. The 15-mg/kg dose did not accumulate with repeated dosing over 5 days. Mean steady-state (±standard deviation) area under the concentration-time curve from 0 to 24 h (AUC(0-24)), maximum concentration of drug in serum (C(max)), half-life (t(1/2)), clearance, and volume of distribution at steady state (V(ss)) for the 15-mg/kg, day 5 dose were 239 ± 45 h·mg/liter, 113 ± 17 mg/liter, 3 ± 0.3 h, 1.1 ± 0.1 ml/min/kg, and 0.24 ± 0.04 liters/kg, respectively. AEs were mild to moderate and rapidly resolved. No evidence of nephrotoxicity or ototoxicity was observed.
Collapse
|
12
|
Nielsen EI, Sandström M, Honoré PH, Ewald U, Friberg LE. Developmental pharmacokinetics of gentamicin in preterm and term neonates: population modelling of a prospective study. Clin Pharmacokinet 2009; 48:253-63. [PMID: 19492870 DOI: 10.2165/00003088-200948040-00003] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND OBJECTIVE Preterm and term newborn infants show wide interindividual variability (IIV) in pharmacokinetic parameters of gentamicin. More extensive knowledge and use of predictive covariates could lead to faster attainment of therapeutic concentrations and a reduced need for concentration monitoring. This study was performed to characterize the population pharmacokinetics of gentamicin in preterm and term neonates and to identify and quantify relationships between patient characteristics and IIV. A secondary aim was to evaluate cystatin C as a marker for gentamicin clearance in this patient population. METHODS Data were collected in a prospective study performed in the Neonatal Intensive Care Unit at the University Children's Hospital, Uppsala, Sweden. Population pharmacokinetic modelling was performed using nonlinear mixed-effects modelling (NONMEM) software. Bodyweight was included as the primary covariate according to an allometric power model. Other evaluated covariates were age (postmenstrual age, gestational age [GA], postnatal age [PNA]), markers for renal function (serum creatinine, serum cystatin C) and concomitant medication with cefuroxime, vancomycin or indometacin. Covariate-parameter relationships were explored using a stepwise covariate model building procedure. The predictive performance of the developed model was evaluated using an independent external dataset for a similar patient population. RESULTS Sixty-one newborn infants (GA range 23.3-42.1 weeks, PNA range 0-45 days) were enrolled in the study. In total, 894 serum gentamicin samples were included in the analysis. The concentration-time profile was described using a three-compartment model. Gentamicin clearance increased with the GA and PNA (included in a nonlinear fashion). The GA was also identified as having a significant influence on the central volume of distribution, with a preterm neonate having a larger central volume of distribution per kilogram of bodyweight than a term neonate. Cystatin C and creatinine were not correlated with gentamicin clearance in this study population. The external dataset was well predicted by the developed model. CONCLUSION Bodyweight and age (GA and PNA) were found to be major factors contributing to IIV in gentamicin clearance in neonates. Based on these data, cystatin C and serum creatinine were not correlated with gentamicin clearance and therefore not likely to be predictive markers of renal function in this patient population. Based on predictions from the developed model, preterm neonates do not reach targeted peak and trough gentamicin concentrations after a standard dosage regimen of 4 mg/kg given once daily, suggesting a need for higher loading doses and prolonged dosing intervals in this patient population.
Collapse
Affiliation(s)
- Elisabet I Nielsen
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | | | | | | | | |
Collapse
|
13
|
Moriarty TF, McElnay JC, Elborn JS, Tunney MM. Sputum antibiotic concentrations: implications for treatment of cystic fibrosis lung infection. Pediatr Pulmonol 2007; 42:1008-17. [PMID: 17902147 DOI: 10.1002/ppul.20671] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The success of antibiotic therapy may be predicted based on the achievement of pharmacodynamic indices (PDIs), which are determined by the susceptibility of the infecting bacteria and the concentrations of antibiotics achieved at the site of infection. The aim of this study was to determine whether PDIs associated with clinical effectiveness for ceftazidime and tobramycin were achieved at the site of infection in the lungs of cystic fibrosis (CF) patients following intravenous administration during treatment of an acute exacerbation. METHODS Serum and sputum samples were collected from 14 CF patients and the concentration of both antibiotics in the samples determined. The susceptibility of bacteria cultured from sputum samples to both antibiotics alone and in combination was also determined. RESULTS A total of 22 Pseudomonas aeruginosa isolates and 4 Burkholderia cepacia complex isolates were cultured from sputum samples with 55% and 4% of isolates susceptible to ceftazidime and tobramycin, respectively. Target PDIs for ceftazidime and tobramycin, an AUC/MIC ratio of 100 and a C(max)/MIC ratio of 10, respectively, were not achieved in serum or sputum simultaneously or even individually for any patient. Although the combination of ceftazidime and tobramycin was synergistic against 20 of the 26 isolates cultured, the concentrations of both antibiotics required for synergy were achieved simultaneously in only 38% of serum and 14% of sputum samples. CONCLUSION Key PDIs associated with clinical effectiveness for ceftazidime and tobramycin were not achieved at the site of infection in the lungs of CF patients.
Collapse
Affiliation(s)
- T F Moriarty
- The Clinical and Practice Research Group, School of Pharmacy, Queen's University Belfast, Belfast, UK
| | | | | | | |
Collapse
|
14
|
Dahl NV. Method of Administering Aminoglycosides during Hemodialysis. Semin Dial 2007. [DOI: 10.1111/j.1525-139x.1997.tb00516.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
15
|
Mouton JW, Jacobs N, Tiddens H, Horrevorts AM. Pharmacodynamics of tobramycin in patients with cystic fibrosis. Diagn Microbiol Infect Dis 2005; 52:123-7. [PMID: 15964500 DOI: 10.1016/j.diagmicrobio.2005.02.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 02/24/2005] [Indexed: 10/25/2022]
Abstract
Relationships between pharmacodynamic indices (PI), such as the area under the concentration-time curve (AUC)/MIC ratio and time > MIC (T(>MIC)), and efficacy have been described for antimicrobial drugs. The use of these quantitative relationships may increase the power to demonstrate significant effects of drugs, obviating the need to include large numbers in comparative trials. Patients with cystic fibrosis (CF) hospitalized for treatment of an infectious exacerbation due to Pseudomonas aeruginosa were eligible for the study. They received tobramycin 3.3 mg/kg tid as initial therapy in combination with ticarcillin 125 mg/kg qid. Blood samples were drawn at t = 0-8 h after infusion. Pharmocokinetic parameters and PI were calculated for every individual and correlated to the relative improvement in forced expiratory volume during the first second (FEV1) and forced vital capacity (FVC) between pretreatment and days 9-11 as a measure of efficacy. The 3 PI fAUC/MIC, f Peak/MIC, and T(>MIC) of tobramycin showed a significant correlation with effect and was the highest for the fAUC/MIC relationships with FEV1 and FVC as determined both by the Emax model as well as Spearman correlations (r = 0.77, P = 0.002 and 0.58, P = 0.036 for FEV1 and FVC). Pharmacokinetic parameters AUC and Peak as such showed no significant correlation with effect, nor did the MIC values. There is a significant relationship between PI of aminoglycosides and efficacy parameter (increase in FEV1 and FVC) in patients with CF. This study demonstrates the applicability of pharmacodynamic relationships in determining efficacy of antimicrobial therapy, by demonstrating a strong PI-effect relationship in a group of only 13 patients.
Collapse
Affiliation(s)
- Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Ziekenhuis Nijmegen, 6532 SZ Nijmegen, The Netherlands.
| | | | | | | |
Collapse
|
16
|
Czock D, Giehl M, Keller F. A concept for pharmacokinetic-pharmacodynamic dosage adjustment in renal impairment: the case of aminoglycosides. Clin Pharmacokinet 2000; 38:367-75. [PMID: 10803457 DOI: 10.2165/00003088-200038040-00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND For patients with impaired renal function, dosage adjustment is necessary for many drugs. Adjustment with respect only to pharmacokinetic parameters may be insufficient. OBJECTIVE To apply the theory of pharmacokinetics and pharmacodynamics to derive a mathematical model that links the concentration-time course and the clinical response by means of the pharmacokinetic-pharmacodynamic parameter 'area under the effect-time curve' (AUETC), and to use this analysis and clinical data for aminoglycosides to calculate dosage adjustments in renal impairment. METHODS Model parameters were estimated for the antimicrobial and nephrotoxic effects of aminoglycosides on the basis of data from the literature. Effect parameters were calculated for various degrees of impaired renal function. RESULTS Use of the model parameters gave a high correlation between the predicted and the observed (literature) values for antimicrobial efficacy and nephrotoxicity. When calculating dosage adjustments in renal impairment, it was possible to hold only one effect (antimicrobial or nephrotoxic) constant by dosage adjustment, whereas the other changed unfavourably. This was explained by differences between the pharmacodynamic parameters for each effect. For high antimicrobial efficacy, a target peak concentration of 9 mg/L (for gentamicin) should be obtained every 48 hours in advanced renal impairment. For low nephrotoxicity, the peak concentration should not exceed 3 mg/L. CONCLUSIONS The parameter AUETC could be a useful pharmacokinetic-pharmacodynamic surrogate marker for dosage adjustment in renal impairment. Using the AUETC method, the beneficial effect can be balanced against the adverse effect.
Collapse
Affiliation(s)
- D Czock
- Medical Department II, University Hospital, Ulm, Germany
| | | | | |
Collapse
|
17
|
Cholewka KA, Ioannides-Demos LL, Liolios L, Paull P, Spicer WJ, McLean AJ. Cephalosporin clinical concentration-time profile modelling and in-vitro bactericidal effects on Escherichia coli. J Antimicrob Chemother 1999; 44:471-6. [PMID: 10588308 DOI: 10.1093/jac/44.4.471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We assessed the cephalosporin concentration-time curve area (AUC), peak concentration, maintained concentration and duration of exposure on in-vitro bactericidal effects on Escherichia coli NCTC 10418, using exposures modelling cephazolin clinical profiles after 1 g and 2 g i.m. injection, equal AUC exposures (288 mg x h/L, 576 mg x h/L; 48 h) and constant exposures to 6, 12 and 24 mg/L. Cephalosporin dosage exposures based on maintenance of concentrations at multiples (6-24 times) of the MIC were not as effective in early or sustained (24 h) bactericidal effect as exposures modelling im injection profiles with equal or lower AUC (P<0.05, ANOVA). Similar results applied to i.m. comparisons with equal AUC exposures modelling extremes of concentration and time exposures. These results indicate a need for intermittent dosage to produce optimally effective profiles, and raise the possibility that these optimum dosing profiles may allow an extension of minimum interdose intervals beyond 8 h.
Collapse
Affiliation(s)
- K A Cholewka
- Department of Clinical Pharmacology, Alfred Hospital, Prahran, Australia
| | | | | | | | | | | |
Collapse
|
18
|
Bromiker R, Adelman C, Arad I, Shapiro M, Levi H. Safety of gentamicin administered by intravenous bolus in the nursery. Clin Pediatr (Phila) 1999; 38:433-5. [PMID: 10416102 DOI: 10.1177/000992289903800711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- R Bromiker
- Department of Neonatology, Hebrew University-Hadassah Medical Center, Jerusalem, Israel
| | | | | | | | | |
Collapse
|
19
|
Murphey ED, Santschi EM, Papich MG. Regional intravenous perfusion of the distal limb of horses with amikacin sulfate. J Vet Pharmacol Ther 1999; 22:68-71. [PMID: 10211721 DOI: 10.1046/j.1365-2885.1999.00180.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- E D Murphey
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | | | | |
Collapse
|
20
|
Ioannides-Demos LL, Liolios L, Wood P, Spicer WJ, McLean AJ. Changes in MIC alter responses of Pseudomonas aeruginosa to tobramycin exposure. Antimicrob Agents Chemother 1998; 42:1365-9. [PMID: 9624477 PMCID: PMC105605 DOI: 10.1128/aac.42.6.1365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pharmacokinetic parameters determining antibiotic efficacy are peak concentrations (Cmax), minimum (trough) concentrations (Cmin), and area under the concentration-time curve (AUC). There is general agreement about the importance of Cmax and AUC for aminoglycosides, but this is not so for maintenance of Cmin. With in vitro exposures modelling in vivo administration, Pseudomonas aeruginosa reference strain ATCC 27853 (MIC, 1 mg/liter) and a higher-MIC (relatively resistant) clinical isolate (MIC, 4 mg/liter) were used to explore bacteriostatic and bactericidal outcomes. With P. aeruginosa ATCC 27853, kill followed a complete bolus profile with a 30-min postdistribution peak (Cpeak30) of 10 mg/liter. The clinical isolate required a Cpeak30 bolus profile of 20 mg/liter for kill, and there was no difference between the efficacies of the bolus and infusion exposures. Bolus profiles that were truncated at 8.5 h and producing sublethal effects were then combined with a wide range of Cmins. With a Cpeak30 profile of 8 mg/liter, P. aeruginosa ATCC 27853 showed a graded bacteriostatic response until a Cmin of > or = 0.8 mg/liter, when complete kill resulted. In contrast, bactericidal effects on the clinical isolate required a Cpeak30 profile of 18 mg/liter with a Cmin of > or = 1.0 mg/liter. Therefore, Cmin also contributes to the bactericidal effect of tobramycin, with requirements showing minor variation with change in MIC. Dosing principles for relatively resistant (higher-MIC) organisms are suggested from the data. Relatively higher aminoglycoside doses via infusion regimens are likely to be needed to generate higher peak concentrations and higher AUC values necessary for bactericidal effect in resistant organisms. Maintenance of trough concentrations on the order of 1.0 mg/liter during the interdose interval will tend to guard against the possibility of inadequate peak and AUC exposures for kill.
Collapse
|
21
|
Rayner CR, Ioannides-Demos LL, Brien JA, Liolios LL, Spicer WJ. Initial concentration-time profile of gentamicin determines efficacy against Enterobacter cloacae ATCC 13047. Antimicrob Agents Chemother 1998; 42:1370-4. [PMID: 9624478 PMCID: PMC105606 DOI: 10.1128/aac.42.6.1370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In vitro studies were designed to investigate the influence of peak drug concentration (Cmax), the area under the concentration-time curve (AUC), and, consequently, the trough concentration on the bactericidal effects of gentamicin against Enterobacter cloacae (MIC, 0.5 mg/liter) by simulating bolus versus infusion administration and bolus dosing with altered drug clearance. Bacteria in the lag phase were exposed to gentamicin concentration-time profiles modelling either bolus or infusion dosing (AUC constant, Cmax changing) with 30-min postdose peak concentrations (Cpeak30) of 4, 6, 8, and 10 mg/liter or bolus dosing with normal and double drug clearance (Cmax constant, AUC changing) corresponding to normal clearance profiles with Cpeak30 of 6 and 8 mg/liter. Exposure to gentamicin caused early bactericidal effects apparent by 2 h, followed by variable bacteriostatic and recovery phases. Exposure to bolus profiles resulted in greater bactericidal activity than the corresponding infusion profile up to a Cpeak30 of 8 mg/liter. At a Cpeak30 of 10 mg/liter, there were no differences in bactericidal effect. Double clearance profiles had a reduced bactericidal effect at 6 mg/liter compared to the corresponding normal clearance profile, but no differences in bactericidal effect were observed for 8-mg/liter double and normal clearance profiles. These results suggest that the initial exposure (i.e., 0 to 30 min) is a more important determinant for bacterial killing than the AUC or trough concentration for this bacterium. Subject to confirmation of these findings with other gram-negative bacteria, to optimize aminoglycoside efficacy the initial exposure (Cmax) should be maximized by giving higher doses or bolus administration at intervals which may not produce detectable trough concentrations. Clinical trials with a broad range of patients, especially those with higher clearance, would confirm these in vitro observations and define optimal dosing recommendations.
Collapse
Affiliation(s)
- C R Rayner
- Department of Pharmacy, Alfred Healthcare Group, Prahran, Victoria, Australia
| | | | | | | | | |
Collapse
|
22
|
Fang W. A novel fluorometric method for evaluation of the postantibiotic effect of antibacterial drugs on mastitis-causing Staphylococcus aureus and Escherichia coli. J Microbiol Methods 1996. [DOI: 10.1016/0167-7012(96)00907-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
23
|
Wood PJ, Ioannides-Demos LL, Bastone EB, Spicer WJ, McLean AJ. Kill kinetics and regrowth patterns of Pseudomonas aeruginosa exposed to concentration-time profiles of tobramycin simulating in vivo infusion and bolus dosing. Antimicrob Agents Chemother 1996; 40:1321-4. [PMID: 8723496 PMCID: PMC163321 DOI: 10.1128/aac.40.5.1321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Pseudomonas aeruginosa ATCC 27853 was exposed to tobramycin concentration-time profiles modelling in vivo bolus and infusion dosing. Dependence of bactericidal and bacteriostatic activity on the initial profile of peak concentration (bolus effect > infusion) and area under the antibiotic concentration-time curve was observed at peak concentration/MIC ratios of 10 or below.
Collapse
Affiliation(s)
- P J Wood
- Department of Clinical Pharmacology, Monash University Department of Microbiology, Prahran, Victoria, Australia
| | | | | | | | | |
Collapse
|
24
|
Firsov AA, Saverino D, Savarino D, Ruble M, Gilbert D, Manzano B, Medeiros AA, Zinner SH. Predictors of effect of ampicillin-sulbactam against TEM-1 beta-lactamase-producing Escherichia coli in an in vitro dynamic model: enzyme activity versus MIC. Antimicrob Agents Chemother 1996; 40:734-8. [PMID: 8851602 PMCID: PMC163189 DOI: 10.1128/aac.40.3.734] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The clinical outcome in patients treated with ampicillin-sulbactam may not always be predictable by disc susceptibility testing or with the MIC as determined with a constant level (4 micrograms/ml) of the beta-lactamase inhibitor (MIC1). The enzyme activities (EA) and the MICs estimated at a constant ratio of ampicillin to sulbactam of 2:1 (MIC2) for 15 TEM-1 beta-lactamase-producing strains of Escherichia coli were examined as alternatives to MIC1 as predictors of the antibacterial effects of this combined drug as studied in an in vitro model which simulates ampicillin-sulbactam pharmacokinetic profiles observed in human peripheral tissues. Integral parameters describing the area under the bacterial count-time curve (AUBC), the area between the normal growth curve, and the killing curve of bacteria exposed to antibiotic (ABBC), and the second parameter expressed as a percentage of its maximal hypothetical value (ABBC/ABBCmax) were calculated. All three parameters correlated well with EA (AUBC, r = 0.93; ABBC, r = -0.88; ABBC/ABBCmax, r = -0.91) and with MIC2 (r = 0.94, -0.94, and -0.95, respectively) but not with MIC1. Both EA and MIC2 can be considered reliable predictors of the antibacterial effect of ampicillin-sulbactam in an in vitro model. These correlations suggest that in vitro kinetic-dynamic models might be useful to reexamine established susceptibility breakpoints obtained with data based on the MIC1 (MICs obtained with constant levels of beta-lactamase inhibitors). These data also suggest that quantitative determinations of bacterial beta-lactamase production and MICs based on the component concentration ratio observed in vivo might be useful predictors of the effect of ampicillin-sulbactam and other beta-lactam-inhibitor combinations.
Collapse
Affiliation(s)
- A A Firsov
- Department of Medicine, Brown University, Providence, Rhode Island 02908, USA
| | | | | | | | | | | | | | | |
Collapse
|
25
|
McLean AJ, Ioannides-Demos LL, Spicer WJ, Christophidis N. Aminoglycoside dosing: one, two or three times a day? Med J Aust 1996; 164:39-42. [PMID: 8559095 DOI: 10.5694/j.1326-5377.1996.tb94111.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The safety and efficacy of conventional aminoglycoside dosing regimens have been proven in clinical trials. Higher doses at longer intervals may be more effective if they result in higher peak serum levels of the drug, but few trials of "once-a-day" dosing have shown improved clinical outcome. The clinical safety of allowing trough serum levels to fall below the minimum inhibitory concentration is not established. Literal "once-a-day" dosing will result in drug accumulation and toxicity in patients with reduced renal clearance, and in potential lack of efficacy and the emergence of antibiotic-resistant organisms in those with increased renal clearance. However, modified "once-a-day" dosing, with the interval determined by the individual's renal clearance rate (hence avoiding subtherapeutic trough levels), will avoid these problems.
Collapse
Affiliation(s)
- A J McLean
- Alfred Group of Hospitals, Melbourne, VIC
| | | | | | | |
Collapse
|
26
|
Ghooi RB, Thatte SM. Inhibition of cell wall synthesis--is this the mechanism of action of penicillins? Med Hypotheses 1995; 44:127-31. [PMID: 7596307 DOI: 10.1016/0306-9877(95)90085-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Penicillins have been shown to inhibit bacterial cell wall synthesis, and interact with penicillin binding proteins, leading to bacterial lysis. These two mechanisms, the former more than the latter are believed to be responsible for their therapeutic potential. It has further been demonstrated that only actively multiplying cells are susceptible to bactericidal effects of the antibiotic, which is in accordance with the suggested mechanism of action. Bacterial growth takes place in terms of size and number, both requiring additional cell wall. An increase in bacterial size is due to an increase in the volume of cytosol and area of the cell wall. Presently there is no proof that the former is the cause of the latter or vice versa. Penicillin by inhibiting cell wall synthesis would inhibit both growth and multiplication. Since the antibiotic is bactericidal to rapidly multiplying cells, its effect on cell wall would interfere with its bactericidal action. As per the present understanding penicillin acts principally by inhibiting cell wall synthesis. There is however a discrepancy between its observed effects and what should logically be expected, which forces us to reexamine the mechanism of action of penicillin. We believe that the present understanding of the action of penicillin is incomplete if not outright faulty. It would be expedient to radically modify the same in view of its implication, for example on drug development.
Collapse
Affiliation(s)
- R B Ghooi
- Medical Division, Unichem Laboratories Ltd., Jogeshwari, (West) Bombay, India
| | | |
Collapse
|