Cefotaxime. A review of its antibacterial activity, pharmacological properties and therapeutic use

Physiologically-based pharmacokinetic modeling and dosing optimization of cefotaxime in preterm and term neonates

BACKGROUND

Cefotaxime is commonly used in treating bacterial infections in neonates. To characterize the pharmacokinetic process in neonates and evaluate different recommended dosing schedules of cefotaxime, a physiologically-based pharmacokinetic (PBPK) model of cefotaxime was established in adults and scaled to neonates.

METHODS

A whole-body PBPK model was built in PK-SIM® software. Three elimination pathways are composed of enzymatic metabolism in the liver, passive filtration through glomerulus, and active tubular secretion mediated by renal transporters. The ontogeny information was applied to account for age-related changes in cefotaxime pharmacokinetics. The established models were verified with realistic clinical data in adults and pediatric populations. Simulations in neonates were conducted and 100% of the dosing interval where the unbound concentration in plasma was above the minimum inhibitory concentration (fT>MIC) was selected as the target index for dosing regimen evaluation.

RESULTS

The developed PBPK models successfully described the pharmacokinetic process of cefotaxime in adults and were scaled to the pediatric population. Good verification results were achieved in both adults' and neonates' PBPK models, indicating a good predictive performance. The optimal dosage regimen of cefotaxime was proposed according to the postnatal age (PNA) and gestational age (GA) of neonates. For preterm neonates (GA < 36 weeks), dosages of 25 mg/kg every 8 hours in PNA 0-6 days and 25 mg/kg every 6 hours in PNA 7-28 days were suggested. For term neonates (GA ≥ 36 weeks), dosages of 33 mg/kg every 8 hours in PNA 0-6 days and 33 mg/kg every 6 hours in PNA 7-28 days were recommended.

CONCLUSIONS

Our study may provide useful experience in practicing PBPK model-informed precision dosing in the pediatric population.

Therapeutic Effects of IL-1RA against Acute Bacterial Infections, including Antibiotic-Resistant Strains

Innate immunity is essential for the anti-microbial defense, but excessive immune activation may cause severe disease. In this study, immunotherapy was shown to prevent excessive innate immune activation and restore the anti-bacterial defense. E. coli-infected Asc-/- mice develop severe acute cystitis, defined by IL-1 hyper-activation, high bacterial counts, and extensive tissue pathology. Here, the interleukin-1 receptor antagonist (IL-1RA), which inhibits IL-1 hyper-activation in acute cystitis, was identified as a more potent inhibitor of inflammation and NK1R- and substance P-dependent pain than cefotaxime. Furthermore, IL-1RA treatment inhibited the excessive innate immune activation in the kidneys of infected Irf3-/- mice and restored tissue integrity. Unexpectedly, IL-1RA also accelerated bacterial clearance from infected bladders and kidneys, including antibiotic-resistant E. coli, where cefotaxime treatment was inefficient. The results suggest that by targeting the IL-1 response, control of the innate immune response to infection may be regained, with highly favorable treatment outcomes, including infections caused by antibiotic-resistant strains.

Phenotypic and genotypic characterization of antibiotic-resistant Salmonella isolated from humans, aquaculture, and poultry in Sri Lanka: A retrospective study

BACKGROUND

In Sri Lanka, foodborne diseases caused by nontyphoidal Salmonella are of increasing concern. We therefore aimed to characterize the dominant Salmonella serovars in humans, poultry, and aquaculture through a One Health approach.

METHODS

We collected isolates from different sectors, confirmed their identities using PCR, screened their antibiotic resistance profiles, and determined their antibiotic resistance genes based on whole-genome sequencing.

RESULTS

Of the 75 Salmonella isolates identified, the majority of serotypes were unidentified. Both Salmonella enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterica serovar Typhimurium (S. Typhimurium) could be isolated from human sources and were also found prevalent in the poultry sector. ST36, ST11 and ST1541 were the dominant serotypes of S. Typhimurium and S. Enteritidis, respectively. Alarmingly, 4% (1/25) of poultry Salmonella isolates were resistant to ciprofloxacin, suggesting an emergence of this phenotype. Moreover, virulence genes were very diverse among S. Enteritidis and S. Typhimurium isolates.

CONCLUSIONS

With the diversity of unidentified serotypes found and the detection of emerging resistances, our study highlights the importance of a One Health approach to monitoring antibiotic resistance. For public health initiatives in Sri Lanka to be successful in mitigating salmonellosis, all three sectors - humans, aquaculture, and poultry - must be tackled concomitantly in a coordinated manner under the One Health approach because antibiotic resistance genes, and even specific sequence types, may be able to spread across the aforementioned sectors. We anticipate that our results will inform public health policies in Sri Lanka to tackle foodborne illnesses.

Culture-directed antibiotics in peritoneal dialysis solutions: a systematic review focused on stability and compatibility

BACKGROUND

This systematic review summarises the stability of less commonly prescribed antibiotics in different peritoneal dialysis solutions that could be used for culture-directed therapy of peritonitis, which would be especially useful in regions with a high prevalence of multidrug antibiotic-resistant strains.

METHODS

A literature search of Medline, Scopus, Embase and Google Scholar for articles published from inception to 25 January, 2023 was conducted. Only antibiotic stability studies conducted in vitro and not recently reviewed by So et al. were included. The main outcomes were chemical, physical, antimicrobial and microbial stability. This protocol was registered in PROSPERO (registration number CRD42023393366).

RESULTS

We screened 1254 abstracts, and 28 articles were included in the study. In addition to those discussed in a recent systematic review (So et al., Clin Kidney J 15(6):1071-1078, 2022), we identified 18 antimicrobial agents. Of these, 9 have intraperitoneal dosing recommendations in the recent International Society for Peritoneal Dialysis (ISPD) peritonitis guidelines, and 7 of the 9 had stability data applicable to clinical practice. They were cefotaxime, ceftriaxone, daptomycin, ofloxacin, and teicoplanin in glucose-based solutions, tobramycin in Extraneal solution only and fosfomycin in Extraneal, Nutrineal, Physioneal 1.36% and 2.27% glucose solutions.

CONCLUSIONS

Physicochemical stability has not been demonstrated for all antibiotics with intraperitoneal dosing recommendations in the ISPD peritonitis guidelines. Further studies are required to determine the stability of antibiotics, especially in icodextrin-based and low-glucose degradation products, pH-neutral solutions.

Hazard and health risk assessment of exposure to pharmaceutical active compounds via toxicological evaluation by zebrafish

The uncontrolled or continuous release of effluents from wastewater treatment plants leads to the omnipresence of pharmaceutical active compounds (PhACs) in the aquatic media. Today, this is a confirmed problem becoming a main subject of twin public and scientific concerns. However, still little information is available about the long-term impacts of these PhACs on aquatic organisms. In this review, efforts were made to reveal correlation between the occurrence in the environment, ecotoxicological and health risks of different PhACs via toxicological evaluation by zebrafish (Danio rerio). This animal model served as a bioindicator for any health impacts after the exposure to these contaminants and to better understand the responses in relation to human diseases. This review paper focused on the calculation of Risk Quotients (RQs) of 34 PhACs based on environmental and ecotoxicological data available in the literature and prediction from the ECOSAR V2.2 software. To the best of the authors' knowledge, this is the first report on the risk assessment of PhACs by the two different methods as mentioned above. RQs showed greater difference in potential environmental risks of the PhACs. These differences in risk values underline the importance of environmental and experimental factors in exposure conditions and the interpretation of RQ values. While the results showed high risk to Danio rerio of the majority of PhACs, risk qualification of the others varied between moderate to insignifiant. Further research is needed to assess pharmaceutical hazards when present in wastewater before discharge and monitor the effectiveness of treatment processes. The recent new advances in the morphological assessment of toxicant-exposed zebrafish larvae for the determination of test compounds effects on the developmental endpoints were also discussed. This review emphasizes the need for strict regulations on the release of PhACs into environmental media in order to minimize their toxicity to aquatic organisms.

An In Vitro Susceptibility Study of Cefotaxime-Sulbactam on Clinical Bacterial Isolates From Various Regions in India: A Comparison With Ceftriaxone-Sulbactam

Background and objective Combining sulbactam with cefotaxime/ceftriaxone augments its antimicrobial activity against β-lactamase-producing bacteria. They are widely used as empirical treatment for many clinical infections. However, there is a scarcity of data on the susceptibility of various organisms to these antibiotics in the Indian region. In light of this, the present in vitro study evaluated the susceptibility of bacterial isolates to cefotaxime-sulbactam and compared it with ceftriaxone-sulbactam. Methodology Clinical samples with positive bacterial cultures from various laboratories in India were subjected to antibiotic sensitivity testing using in vitro E-test strips and disk diffusion methods to determine the minimum inhibitory concentration (MIC) and zone of inhibition (ZOI), respectively. MIC₅₀ and MIC₉₀ values were determined along with the measurement of the ZOI for the effectiveness of antibiotics. Interpretations of MIC and ZOI values were made as per the criteria set by the Clinical and Laboratory Standards Institute (CLSI) guidelines to estimate the proportion of sensitive organisms. Results Among 400 clinical isolates evaluated, Escherichia coli (E. coli) (47.75%) was the most common organism isolated followed by Klebsiella (26%), Salmonella (7.75%), Proteus (3.8%), and Acinetobacter (2.8%). The mean ZOI was found significantly higher for E. coli, Klebsiella, and Salmonella in the cefotaxime-sulbactam group than in the ceftriaxone-sulbactam group. MIC₅₀ values for E. coli and Klebsiella were 0.25 and 0.19 µg/ml, respectively in the cefotaxime-sulbactam group as compared to 0.38 and 0.25 µg/ml, respectively for ceftriaxone-sulbactam. The proportion of sensitive isolates was also higher in the cefotaxime-sulbactam group for E. coli, Klebsiella, and Salmonella. Conclusions The in vitro effect of cefotaxime-sulbactam on organisms is similar to that of ceftriaxone-sulbactam in terms of MIC, ZOI, and proportion of sensitivity based on our study involving clinical isolates from various parts of India. Cefotaxime-sulbactam may be preferred in the empirical management of various clinical infections.

Towards Antibiotic Synthesis in Continuous-Flow Processes

Continuous-flow chemistry has become a mainstream process and a notable trend among emerging technologies for drug synthesis. It is routinely used in academic and industrial laboratories to generate a wide variety of molecules and building blocks. The advantages it provides, in terms of safety, speed, cost efficiency and small-equipment footprint compared to analog batch processes, have been known for some time. What has become even more important in recent years is its compliance with the quality objectives that are required by drug-development protocols that integrate inline analysis and purification tools. There can be no doubt that worldwide government agencies have strongly encouraged the study and implementation of this innovative, sustainable and environmentally friendly technology. In this brief review, we list and evaluate the development and applications of continuous-flow processes for antibiotic synthesis. This work spans the period of 2012-2022 and highlights the main cases in which either active ingredients or their intermediates were produced under continuous flow. We hope that this manuscript will provide an overview of the field and a starting point for a deeper understanding of the impact of flow chemistry on the broad panorama of antibiotic synthesis.

Searching glycolate oxidase inhibitors based on QSAR, molecular docking, and molecular dynamic simulation approaches

Primary hyperoxaluria type 1 (PHT1) treatment is mainly focused on inhibiting the enzyme glycolate oxidase, which plays a pivotal role in the production of glyoxylate, which undergoes oxidation to produce oxalate. When the renal secretion capacity exceeds, calcium oxalate forms stones that accumulate in the kidneys. In this respect, detailed QSAR analysis, molecular docking, and dynamics simulations of a series of inhibitors containing glycolic, glyoxylic, and salicylic acid groups have been performed employing different regression machine learning techniques. Three robust models with less than 9 descriptors-based on a tenfold cross (Q² _CV) and external (Q² _EXT) validation-were found i.e., MLR1 (Q² _CV = 0.893, Q² _EXT = 0.897), RF1 (Q² _CV = 0.889, Q² _EXT = 0.907), and IBK1 (Q² _CV = 0.891, Q² _EXT = 0.907). An ensemble model was built by averaging the predicted pIC₅₀ of the three models, obtaining a Q² _EXT = 0.933. Physicochemical properties such as charge, electronegativity, hardness, softness, van der Waals volume, and polarizability were considered as attributes to build the models. To get more insight into the potential biological activity of the compouds studied herein, docking and dynamic analysis were carried out, finding the hydrophobic and polar residues show important interactions with the ligands. A screening of the DrugBank database V.5.1.7 was performed, leading to the proposal of seven commercial drugs within the applicability domain of the models, that can be suggested as possible PHT1 treatment.

Sustained Release In Situ Thermogelling Hydrogel of Cerebrolysin for Treatment of Facial Nerve Axotomy in Rats

PURPOSE

The most essential principle in managing facial nerve (FN) injury is proper diagnosis and early treatment. This study evaluated local application of different concentrations and injection intervals of Cerebrolysin hydrogel (CBLH) for facial nerve axotomy (FNA) treatment. We hypothesized that local application of CBLH may provide a sustained release of Cerebrolysin and enhance neural regeneration.

METHODS

The authors implemented a randomized, controlled, blinded animal study. The sample was composed of the right FN. Functionally, eye-blink reflex was evaluated 2 and 4 weeks postoperatively. All rats were euthanized after 4 weeks, and nerve regeneration was evaluated histopathologically and immunohistochemically (IHC) with antibody against neurofilament (anti-NF) and S100 proteins. Descriptive and correlation statistics were computed, and the P value was set at .05.

RESULTS

The sample was composed of 72 adult male rats equally allocated into 8 groups. Groups I and V served as control groups and were injected with phosphate buffered saline once and four times, respectively. Rest of the groups were injected with 5%, 10%, and 15% CBLH once in groups II, III, IV and weekly in groups VI, VII, and VIII. CBLH showed statistically significant FN regeneration by enhancing Schwann and axonal growth compared to control group especially with single injection of 10%, 15%, and 5% 4-time injections, where the P value was less than .001. Significant improvement of eye-blink reflex was correlated with structural improvement associated with CBLH.

CONCLUSION

Finally, CBLH enhanced nerve regeneration and rehabilitation after FNA in rats. Therefore, it could be considered as an alternative treatment of FNA. More experimental and clinical trials should be considered to detect the effectiveness of CBLH in neural regeneration.

Discovery and Development of Antibacterial Agents: Fortuitous and Designed

Today, antibacterial drug resistance has turned into a significant public health issue. Repeated intake, suboptimal and/or unnecessary use of antibiotics, and, additionally, the transfer of resistance genes are the critical elements that make microorganisms resistant to conventional antibiotics. A substantial number of antibacterials that were successfully utilized earlier for prophylaxis and therapeutic purposes have been rendered inadequate due to this phenomenon. Therefore, the exploration of new molecules has become a continuous endeavour. Many such molecules are at various stages of investigation. A surprisingly high number of new molecules are currently in the stage of phase 3 clinical trials. A few new agents have been commercialized in the last decade. These include solithromycin, plazomicin, lefamulin, omadacycline, eravacycline, delafloxacin, zabofloxacin, finafloxacin, nemonoxacin, gepotidacin, zoliflodacin, cefiderocol, BAL30072, avycaz, zerbaxa, vabomere, relebactam, tedizolid, cadazolid, sutezolid, triclosan and afabiacin. This article aims to review the investigational and recently approved antibacterials with a focus on their structure, mechanisms of action/resistance, and spectrum of activity. Delving deep, their success or otherwise in various phases of clinical trials is also discussed while attributing the same to various causal factors.

Comparison of Enterococcus faecalis Biofilm Removal Efficiency among Bacteriophage PBEF129, Its Endolysin, and Cefotaxime

Enterococcus faecalis is a Gram-positive pathogen which colonizes human intestinal surfaces, forming biofilms, and demonstrates a high resistance to many antibiotics. Especially, antibiotics are less effective for eradicating biofilms and better alternatives are needed. In this study, we have isolated and characterized a bacteriophage, PBEF129, infecting E. faecalis. PBEF129 infected a variety of strains of E. faecalis, including those exhibiting antibiotic resistance. Its genome is a linear double-stranded DNA, 144,230 base pairs in length. Its GC content is 35.9%. The closest genomic DNA sequence was found in Enterococcus phage vB_EfaM_Ef2.3, with a sequence identity of 99.06% over 95% query coverage. Furthermore, 75 open reading frames (ORFs) were functionally annotated and five tRNA-encoding genes were found. ORF 6 was annotated as a phage endolysin having an L-acetylmuramoyl-l-alanine amidase activity. We purified the enzyme as a recombinant protein and confirmed its enzymatic activity. The endolysin’s host range was observed to be wider than its parent phage PBEF129. When applied to bacterial biofilm on the surface of in vitro cultured human intestinal cells, it demonstrated a removal efficacy of the same degree as cefotaxime, but much lower than its parent bacteriophage.

Interaction of small molecules with the SARS-CoV-2 papain-like protease: In silico studies and in vitro validation of protease activity inhibition using an enzymatic inhibition assay

The SARS-CoV-2 virus is causing COVID-19, an ongoing pandemic, with extraordinary global health, social, and political implications. Currently, extensive research and development efforts are aimed at producing a safe and effective vaccine. In the interim, small molecules are being widely investigated for antiviral effects. With respect to viral replication, the papain-like (PL^pro) and main proteases (M^pro), are critical for processing viral replicase polypeptides. Further, the PL^pro possesses deubiquitinating activity affecting key signalling pathways, including inhibition of interferon and innate immune antagonism. Therefore, inhibition of PL^pro activity with small molecules is an important research direction. Our aim was to focus on identification of potential inhibitors of the protease activity of SARS-CoV-2 PL^pro. We investigated 300 small compounds derived predominantly from our OliveNet™ library (222 phenolics) and supplemented with synthetic and dietary compounds with reported antiviral activities. An initial docking screen, using the potent and selective noncovalent PL^pro inhibitor, GRL-0617 as a control, enabled a selection of 30 compounds for further analyses. From further in silico analyses, including docking to scenes derived from a publicly available molecular dynamics simulation trajectory (100 μs PDB 6WX4; DESRES-ANTON-11441075), we identified lead compounds for further in vitro evaluation using an enzymatic inhibition assay measuring SARS-CoV-2 PL^pro protease activity. Our findings indicate that hypericin possessed inhibition activity, and both rutin and cyanidin-3-O-glucoside resulted in a concentration-dependent inhibition of the PL^pro, with activity in the micromolar range. Overall, hypericin, rutin, and cyanidin-3-O-glucoside can be considered lead compounds requiring further characterisation for potential antiviral effects in appropriate model systems.

Natural variants modify Klebsiella pneumoniae carbapenemase (KPC) acyl-enzyme conformational dynamics to extend antibiotic resistance

Class A serine β-lactamases (SBLs) are key antibiotic resistance determinants in Gram-negative bacteria. SBLs neutralize β-lactams via a hydrolytically labile covalent acyl-enzyme intermediate. Klebsiella pneumoniae carbapenemase (KPC) is a widespread SBL that hydrolyzes carbapenems, the most potent β-lactams; known KPC variants differ in turnover of expanded-spectrum oxyimino-cephalosporins (ESOCs), for example, cefotaxime and ceftazidime. Here, we compare ESOC hydrolysis by the parent enzyme KPC-2 and its clinically observed double variant (P104R/V240G) KPC-4. Kinetic analyses show that KPC-2 hydrolyzes cefotaxime more efficiently than the bulkier ceftazidime, with improved ESOC turnover by KPC-4 resulting from enhanced turnover (kcat), rather than altered KM values. High-resolution crystal structures of ESOC acyl-enzyme complexes with deacylation-deficient (E166Q) KPC-2 and KPC-4 mutants show that ceftazidime acylation causes rearrangement of three loops; the Ω, 240, and 270 loops, which border the active site. However, these rearrangements are less pronounced in the KPC-4 than the KPC-2 ceftazidime acyl-enzyme and are not observed in the KPC-2:cefotaxime acyl-enzyme. Molecular dynamics simulations of KPC:ceftazidime acyl-enyzmes reveal that the deacylation general base E166, located on the Ω loop, adopts two distinct conformations in KPC-2, either pointing "in" or "out" of the active site; with only the "in" form compatible with deacylation. The "out" conformation was not sampled in the KPC-4 acyl-enzyme, indicating that efficient ESOC breakdown is dependent upon the ordering and conformation of the KPC Ω loop. The results explain how point mutations expand the activity spectrum of the clinically important KPC SBLs to include ESOCs through their effects on the conformational dynamics of the acyl-enzyme intermediate.

Biotechnological Interventions for Ginsenosides Production

Ginsenosides are secondary metabolites that belong to the triterpenoid or saponin group. These occupy a unique place in the pharmaceutical sector, associated with the manufacturing of medicines and dietary supplements. These valuable secondary metabolites are predominantly used for the treatment of nervous and cardiac ailments. The conventional approaches for ginsenoside extraction are time-consuming and not feasible, and thus it has paved the way for the development of various biotechnological approaches, which would ameliorate the production and extraction process. This review delineates the biotechnological tools, such as conventional tissue culture, cell suspension culture, protoplast culture, polyploidy, in vitro mutagenesis, hairy root culture, that have been largely implemented for the enhanced production of ginsenosides. The use of bioreactors to scale up ginsenoside yield is also presented. The main aim of this review is to address the unexplored aspects and limitations of these biotechnological tools, so that a platform for the utilization of novel approaches can be established to further increase the production of ginsenosides in the near future.

Exploring metabolic adaptation of Streptococcus pneumoniae to antibiotics

The Gram-positive bacterium Streptococcus pneumoniae is one of the common causes of community acquired pneumonia, meningitis, and otitis media. Analyzing the metabolic adaptation toward environmental stress conditions improves our understanding of its pathophysiology and its dependency on host-derived nutrients. In this study, extra- and intracellular metabolic profiles were evaluated to investigate the impact of antimicrobial compounds targeting different pathways of the metabolome of S. pneumoniae TIGR4Δcps. For the metabolomics approach, we analyzed the complex variety of metabolites by using ¹H NMR, HPLC-MS, and GC–MS as different analytical techniques. Through this combination, we detected nearly 120 metabolites. For each antimicrobial compound, individual metabolic effects were detected that often comprised global biosynthetic pathways. Cefotaxime altered amino acids metabolism and carbon metabolism. The purine and pyrimidine metabolic pathways were mostly affected by moxifloxacin treatment. The combination of cefotaxime and azithromycin intensified the stress response compared with the use of the single antibiotic. However, we observed that three cell wall metabolites were altered only by treatment with the combination of the two antibiotics. Only moxifloxacin stress-induced alternation in CDP-ribitol concentration. Teixobactin-Arg10 resulted in global changes of pneumococcal metabolism. To meet the growing requirements for new antibiotics, our metabolomics approach has shown to be a promising complement to other OMICs investigations allowing insights into the mode of action of novel antimicrobial compounds.

Binding properties of a peptide derived from beta-lactamase inhibitory protein

To overcome the antibiotic resistance mechanism mediated by beta-lactamases, small-molecule beta-lactamase inhibitors, such as clavulanic acid, have been used. This approach, however, has applied selective pressure for mutations that result in beta-lactamases no longer sensitive to beta-lactamase inhibitors. On the basis of the structure of beta-lactamase inhibitor protein (BLIP), novel peptide inhibitors of beta-lactamase have been constructed. BLIP is a 165-amino-acid protein that is a potent inhibitor of TEM-1 beta-lactamase (K(i) = 0.3 nM). The cocrystal structure of TEM-1 beta-lactamase and BLIP indicates that residues 46 to 51 of BLIP make critical interactions with the active site of TEM-1 beta-lactamase. A peptide containing this six-residue region of BLIP was found to retain sufficient binding energy to interact with TEM-1 beta-lactamase. Inhibition assays with the BLIP peptide reveal that, in addition to inhibiting TEM-1 beta-lactamase, the peptide also inhibits a class A beta-lactamase and a class C beta-lactamase that are not inhibited by BLIP. The crystal structures of class A and C beta-lactamases and two penicillin-binding proteins (PBPs) reveal that the enzymes have similar three-dimensional structures in the vicinity of the active site. This similarity suggests that the BLIP peptide inhibitor may have a broad range of activity that can be used to develop novel small-molecule inhibitors of various classes of beta-lactamases and PBPs.

A comparison of prophylactic antibiotic regimens against airborne orthopaedic wound contamination

Deep infection remains a major complication of joint replacement surgery despite advances in theatre design, surgical technique and antibiotic prophylaxis. Major randomized controlled trials to determine the most effective antibiotic prophylaxis are difficult to construct and interpret. In a conventional theatre, most orthopaedic intra-operative wound contamination arrives by the airborne route. This paper describes a unique method used to compare antibiotics against airborne bacteria. Seven antibiotics were incorporated into blood agar at concentrations equivalent to serum levels. Plates were then exposed to airborne theatre bacteria using a multiple synchronous collection technique. After incubation, the percentage kill was calculated for each antibiotic. At concentrations equivalent to serum level 1h post i.v. dose, all the antibiotics proved highly effective, with kill rates > 95%. Imipenem and co-amoxiclav significantly outperformed the other antibiotics with kill rates of 99.6% and 99.4%, respectively. At trough levels, the antibiotics achieved kill rates from 61% to 97.6%. Future randomized controlled trials comparing large numbers of antibiotics in the setting of an already low infection rate are inappropriate. This technique for comparing antibiotic prophylaxis in quick, inexpensive and repeatable. The superiority of imipenem is not unexpected, but of more interest is the effectiveness of co-amoxiclav over the presently favoured cefuroxime.

Cefotaxime. A reappraisal of its antibacterial activity and pharmacokinetic properties, and a review of its therapeutic efficacy when administered twice daily for the treatment of mild to moderate infections

Cefotaxime is well established as an effective and well tolerated antibacterial drug for 3 times daily parenteral treatment of a variety of moderate to severe infections in hospitalised patients. Its frequency of administration has recently been reassessed with a 12-hourly regimen. Comparative studies in hospitalised patients with nosocomial or community-acquired lower respiratory tract infections, demonstrate the similar clinical and bacteriological efficacy of twice daily cefotaxime 1 or 2 g and the same daily dose of ceftriaxone, usually administered once daily. Cefotaxime 2 g twice daily was also similar in efficacy to ceftriaxone 2 g once daily. Retrospective and post-marketing studies also reveal the similar efficacy of cefotaxime administered twice and 3 times daily, and pharmacoeconomic studies suggest that total direct costs of treatment with cefotaxime compared is similar to that with other third generation cephalosporins in currently used dosage regimens. When administered twice daily, cefotaxime is, thus, an effective antibacterial agent for the treatment of hospitalised patients outside the intensive care unit with a variety of mild to moderate non-CNS infections caused by susceptible organisms. When appropriately administered twice daily there is potential to lower the cost of antibacterial treatment without compromising efficacy.

Comparative serum bactericidal activities of ceftizoxime and cefotaxime against intermediately penicillin-resistant Streptococcus pneumoniae

In a randomized crossover study involving 12 healthy volunteers, 1 g of ceftizoxime or cefotaxime was administered intravenously every 12 h for a total of three doses on two separate weekends. The duration of serum bactericidal titers (SBTs) greater than 1:2 and the time serum drug concentrations remained above the MIC (T > MIC) were determined against three clinical isolates of Streptococcus pneumoniae with intermediate resistance to penicillin. The duration of SBTs and T > MIC for both antimicrobial agents exceeded 50% of the dosing interval for all isolates. Ceftizoxime's T > MIC was statistically greater than that of cefotaxime, indicating that its longer half-life in serum (1.7 h) compared with that of cefotaxime (approximately 1 h) compensates for its slightly lower microbiologic activity against the penicillin-resistant pneumococci tested in this study.

The effect of induced fever on the biokinetics of norfloxacin and its interaction with probenecid in goats

The kinetic profiles of norfloxacin were evaluated in afebrile, febrile and probenecid pre-treated (70 mg/kg orally) febrile goats after a single intravenous (i.v.) dose (5 mg/kg). Fever was induced and maintained for 12 h by injecting Escherichia coli endotoxin (0.2 microgram/kg, i.v.) and repeating it in half the dose (0.1 microgram/kg) 5 h later. The plasma pharmacokinetic values for norfloxacin were best represented using a two-compartment open model. The peak norfloxacin plasma level of 90.52 +/- 3.18 micrograms/ml attained in the probenecid pre-treated febrile goats was higher than that in the febrile (75.46 +/- 0.72 micrograms/ml) or afebrile goats (62.25 +/- 1.23 micrograms/ml). ClB and Kel values were significantly (p < 0.01) decreased in febrile compared with afebrile goats. These values were further reduced in febrile goats after probenecid pre-treatment. However, t1/2 beta was not affected by the fever-probenecid interaction. Norfloxacin may be used as an infusion with probenecid in caprine diseases where very high plasma levels are required to combat resistant organisms such as Bacteroides.

Pharmacokinetics of cefotaxime in dialysis patients

A literature review was carried out to assess the effect of hemodialysis, hemofiltration, and continuous ambulatory peritoneal dialysis on the pharmacokinetics of cefotaxime, particularly in patients with severe renal impairment. It was concluded that the dosage of cefotaxime, adjusted for renal function, would require no further adjustment during peritoneal dialysis or hemofiltration.

Pharmacokinetics of cefotaxime and desacetylcefotaxime in the young

Available information on the pharmacokinetics of cefotaxime (CTX) and desacetylcefotaxime (dCTX) indicates that their disposition depends on development, with the greatest changes occurring during the 1st year of life. To a great extent, these changes reside with the acquisition of renal function (e.g., both glomerular filtration and active tubular secretion) during the 1st year of life. When the impact of development on CTX and dCTX disposition is considered, it is apparent that age-appropriate pharmacokinetic data can be used to individualize CTX dosing regimens according to age. Also, alternative dosing regimens that have been proven to be both safe and effective can be justified.

Experience with cefotaxime in the treatment of spontaneous bacterial peritonitis in cirrhosis

Spontaneous bacterial peritonitis (SBP) is a severe infectious complication in cirrhotic patients, and initial antibiotic therapy must be empirical. An initial study published in 1985 found that cefotaxime administered at a dose of 2 g every 4 h was more effective and safer than the combination of tobramycin-ampicillin. Since then, cefotaxime has been considered the agent of choice in the empiric therapy of SBP. Subsequent publications showed that a dosage of 2 g every 6 h was also adequate in this infection. More recent studies have demonstrated that the high efficacy of cefotaxime in SBP can be maintained by using lower dosages than those used in initial investigations. In one of these studies, a dose of 2 g every 8 h for 5 days was found to be as effective as the same dose for 10 days. Finally, a prospective, randomized multicenter trial aimed at comparing the efficacy of two different dosages of cefotaxime, 2 g every 6 h versus 2 g every 12 in a large series of cirrhotic patients with SBP, showed that both dosages resulted in similar rates of resolution of infection and survival. Despite the reasonably adequate rate of infection resolution in SBP patients, the in-hospital mortality rate remains high as a result of complications such as renal failure. Further studies should therefore be addressed to reducing the incidence of these complications and thus improving survival.

Two different dosages of cefotaxime in the treatment of spontaneous bacterial peritonitis in cirrhosis: results of a prospective, randomized, multicenter study

Cefotaxime (CTX) is considered one of the first-choice antibiotics in the therapy of spontaneous bacterial peritonitis (SBP) in cirrhosis. Because CTX is largely metabolized in the liver, this drug may also be effective in SBP by administering lower doses than those habitually used. To investigate this possibility, a prospective, randomized, multicenter study was performed to compare the therapeutic efficacy of two different dosages of CTX in 143 patients with SBP: 71 (group I) were allocated to receive a high dose (2 g every 6 hours, which is one of the most frequently recommended doses in this infection), and 72 (group II) were allocated to receive a low dose (2 g every 12 hours). At inclusion, both groups were similar in relation to clinical and laboratory data, with the exception of a higher incidence of positive ascitic fluid culture in group I than in group II (59% vs. 40%; P = .029). The rate of infection resolution was similar for both groups (77% vs. 79%). Hospital survival was also similar in both groups (69% vs. 79%). No difference was observed between patients with positive or negative ascitic fluid cultures with regard to infection resolution and patient survival. The duration of antibiotic therapy was similar in both groups (9.0 +/- 3.3 days in group I vs. 8.8 +/- 3.1 days in group II). In a subset of 13 patients from group I and 11 patients from group II CTX levels were determined in serum (peak and trough) and ascitic fluid (concomitantly with trough serum). Peak serum levels were similar in patients from both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of selective decontamination of the digestive tract on microbial biofilm formation on endotracheal tubes from artificially ventilated patients

The effect of selective decontamination of the digestive tract on the nature and incidence of microbial biofilm formation on endotracheal tubes was assessed. Thirty endotracheal tubes were obtained post-extubation from patients in the intensive care unit who had been ventilated for a 1 to 15 day period and who did or did not receive the antibiotic regimen. Extensive biofilm formation was identified by scanning electron microscopy on 97% of tubes examined. Endotracheal tube biofilm in tubes obtained from patients who received selective decontamination of the digestive tract showed a high prevalence of colonization with yeast (4 of 15 tubes) and gram-positive bacteria (streptococci, staphylococci and diphtheroids) (14 of 15 tubes). Staphylococcus aureus was isolated only from this group. Pseudomonas spp. were isolated from 2 of 15 tubes in both patient groups. Enteric gram-negative organisms (coliforms, Klebsiella and Proteus spp.) were isolated only from tubes of patients who did not receive the antibiotic regimen (4 of 15 tubes). Yeasts, however, were not isolated from these tubes. Group D streptococcal isolates were resistant to tobramycin as were half of the Staphylococcus aureus isolates. For gram-negative bacteria, the MIC of tobramycin was in the range 1-64 micrograms/ml and the MIC of polymyxin in the range 0.5-16 micrograms/ml. Although a reduction was observed in the incidence of gram-negative microorganisms, this antibiotic regimen does not inhibit biofilm formation on the endotracheal tube by other pathogens associated with pneumonia in ventilated patients. This persistent nidus may be a factor in the pathogenesis of nosocomial pneumonia.

Infections in the surgical setting: epidemiology and effect of treatment with cefotaxime in a multicenter trial including 3,032 patients

Hospital-acquired infections still represent a serious threat to the surgical patient. A nationwide survey of 259 Italian surgical wards involving 11,343 patients was conducted in October 1988. Hospital-acquired infections were recorded in 565 (5%) patients: the microorganisms most commonly involved were gram-negative rods (60% of all isolates), 41% of the infected patients presented one or more intrinsic predisposing factor, and 65% had undergone some invasive procedure. The studied group represented 23% of all surgical patients in the country on the days of the survey. Following the epidemiologic survey, an open multicenter study was conducted in the same wards to evaluate the efficacy and tolerability of cefotaxime (1 g, 2 or 3 times per day) in the treatment of nosocomial surgical infections. Among 3,032 evaluable patients, 1,295 intra-abdominal, 610 wound and soft tissue, 554 urinary, and 367 respiratory infections were observed. Treatment was judged to be clinically effective in 94% of patients, and side effects, mostly involving the gastrointestinal tract, were observed in 1.4% of patients; but interruption of the treatment was required only in 19 patients (0.6%). This study confirms that cefotaxime, after over a decade of use, retains high efficacy in the treatment for nosocomial infections and induces a low rate of side effects.

Considerations in dosage selection for third generation cephalosporins

Pharmacokinetic parameters of third generation cephalosporins vary widely, requiring different dosage regimens and adjustment methods for each agent. Although their antibacterial spectrum favours their usage in infections caused by aerobic Gram-negative organisms, due to their limited post-antibiotic effect against these organisms, dosage regimens should ensure that free drug concentrations at the site of infection remain above the minimum inhibitory concentration for as much of the dosage interval as possible in patients with normal host defence mechanisms and for the entire dosage interval in immunocompromised patients. Altered protein binding encountered in various disease states can affect both microbiological and pharmacokinetic properties especially for drugs with high protein binding. Since the concentrations at the site of action are often different from those in serum, a higher or lower range of dosages needs to be selected depending on the target site. Decreased renal function affects the elimination of most third generation cephalosporins, whereas the presence of hepatic disease does not generally necessitate dosage adjustment. Because of the complex age-related physiological changes in paediatric and elderly patients, dosage should be adjusted on the basis of the reported pharmacokinetic data in these populations. The usual recommended dose may or may not be optimal in a given condition depending on the complex interactions between pharmacokinetic, microbiological and other host factors.

Comparative study of pharmacokinetics and serum bactericidal activity of ceftizoxime and cefotaxime

Single 2-g intravenous doses of ceftizoxime (CZX) and cefotaxime (CTX) were given over 30 min to 10 adult volunteers in a crossover manner on two separate occasions. Concentrations of CZX, CTX, and the primary metabolite of CTX, desacetylcefotaxime (dCTX), in serum, suction-induced-blister fluid, and urine were determined by high-pressure liquid chromatography. Pharmacokinetic parameters were estimated by using an extended least-squares modeling program (MKMODEL). CZX exhibited a half-life in serum (2.05 h) longer than that of CTX (1.43 h) but comparable to that of dCTX (2.02 h). The percentage of penetration in blister fluid, estimated by area under the curve ratios, was significantly higher for CZX (164.4%) than for CTX (60.8%). Serum bactericidal activity, determined for volunteer samples at 1, 6, 8, and 12 h after patients were dosed, against clinical isolates of the Bacteroides fragilis group, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, and Morganella morganii were significantly higher for CZX than those for CTX against members of the family Enterobacteriaceae at all times. Serum bactericidal titers against B. fragilis were also higher for CZX than for CTX at 1 h postinfusion. Neither CZX nor CTX exhibited any bactericidal activity at any other time against the B. fragilis group. In conclusion, the serum bactericidal activity of CZX was greater and more-prolonged than that of CTX against tested strains in spite of the in vitro synergistic contribution of dCTX to CTX, equal serum elimination half-lives of dCTX and CZX, and similar antibacterial activity and similar instability under microbiological testing for CZX and CTX.

Antibiotic prophylaxis of respiratory tract infection in mechanically ventilated patients. A prospective, blinded, randomized trial of the effect of a novel regimen

The objective of this study was to assess the effect of a novel regimen of antibiotic prophylaxis on the incidence of lower respiratory tract infection in patients requiring prolonged (at least five days) mechanical ventilation. The design was a controlled, prospective, randomized trial, with blinded comparison of the groups regarding the incidence of respiratory tract infection in an intensive care unit of a university hospital. After determination of the APACHE II score for severity of disease, 88 patients were randomly divided in three groups. Twenty-four of these patients did not complete five days of mechanical ventilation, and eight were withdrawn for other reasons. Fifty-six patients (18 in group 1, 21 in group 2, 17 in group 3) completed the study. Patients in both control groups 1 and 2 did not receive antibiotic prophylaxis, but the two groups differed in the antibiotic policy in case of infection. Patients in group 3 received antibiotic prophylaxis consisting of norfloxacin, polymyxin E, and amphotericin B, applied topically in oropharynx and stomach from time of ICU admission until extubation, and intravenous cefotaxime 500 mg three times a day during the first five days of admission. In both control groups, about 90 percent of the patients acquired microbial colonization of oropharynx or stomach. In group 3, only 12 percent and 24 percent of the patients acquired colonization of oropharynx and stomach, respectively (p less than 0.001). This resulted in a reduction of the incidence of lower respiratory tract infection (78 percent in group 1, 62 percent in group 2, 6 percent in group 3 [p = 0.0001]). The regimen of antibiotic prophylaxis studied prevented respiratory tract infection in mechanically ventilated patients. Antibiotic prophylaxis should be considered in all patients expected to require prolonged mechanical ventilation.

Pharmacological properties of cephalosporins

The cephalosporins differ in the substituents attached at the 3 and/or 7 positions of the molecule. Very schematically, substitution at C3 mainly modifies the overall pharmacokinetic properties whereas substitution at position 7 influences the antibacterial characteristics. When using the more common "generation" system for classification, three generations can be distinguished on the basis of their antibacterial spectrum, potency, and their stability to beta-lactamases. The first generation cephalosporins have similar antibacterial and pharmacokinetic characteristics. C3-esterified cephalosporins (e.g. cephalothin and cephapirin) are significantly metabolized. The so-called second generation cephalosporins exhibit only minor differences with respect to the pharmacokinetic properties in contrast to the third generation cephalosporins. The apparent volumes of distribution of most cephalosporins range between seven and 20 1, indicating that they mainly stay in the extracellular space. Plasma protein binding is variable from compound to compound. Generally, the major route of elimination of most cephalosporins is via the kidney except for cefoperazone and ceftriaxone which are both excreted to a large extent by the biliary route. With the exception of cefonicid, cefotetan and cefriaxone, which have longer elimination half-lives (i.e. 4.5, 3.5 and around eight hours), all other cephalosporins have a half-life ranging from 0.5 to 2.5 hours. The pattern of adverse reactions is comparable for all the cephalosporins although there are slight differences in both the incidence and the type of reactions. The major categories of adverse reactions are gastrointestinal, dermatologic, hypersensitivity, haematologic, hepatic, renal as well as CNS effects. Alcohol intolerance (antabus-like effect) can occur when cephalosporins containing the NMTT moiety are administered concomitantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of cefotaxime and desacetylcefotaxime in patients with liver disease

The dispositions of cefotaxime and its metabolite desacetylcefotaxime were investigated in patients with different forms of chronic parenchymal liver disease (CPLD). A total of 31 subjects (27 patients and 4 controls) received a single 2-g dose of cefotaxime by infusion, and serial blood samples were drawn. The area under the concentration-time curve ranged from 176 to 241 micrograms.h/ml, the apparent half-life ranged from 1.49 to 2.42 h, and clearance ranged from 2.06 to 3.10 ml/min/kg in patients with four different forms of CPLD. The area under the concentration-time curve and the apparent half-life of desacetylcefotaxime ranged from 72 to 128 micrograms.h/ml and 7.1 to 13.4 h, respectively. Pharmacokinetic parameters were significantly different in patients with CPLD compared with those in control subjects and were related to clinical indices of hepatic impairment. Modest accumulation of cefotaxime in patients with severe hepatic impairment is unlikely to produce toxicity because of its high therapeutic index, and dosing modifications may not be required.

Nosocomial pneumonia: comparative multicentre trial between monotherapy with cefotaxime and treatment with antibiotic combinations

In a multicentre clinical trial involving 32 hospitals, 588 adult patients diagnosed with nosocomial pneumonia and not receiving mechanical ventilation were treated randomly with monotherapy with cefotaxime or the antibiotic combination routinely used in each particular hospital. Both groups of patients were similar regarding demographic data, concurrent diseases, additional therapies and causative organism. Protocol violations were recorded in 40 patients, and these patients were excluded from the evaluation of treatment efficacy. The cure rate was 79% in the cefotaxime group and 71% in the group receiving antibiotic combinations; this difference is statistically significant (p = 0.03, Fisher's two-tailed test). In the patients receiving combinations of cephalosporins having activity predominantly against gram-positive organisms plus aminoglycosides, the cure rate obtained was very low. The frequency of serious adverse reactions was significantly higher in the group treated with antibiotic combinations. It is concluded that monotherapy with cefotaxime is the regimen that offers better results for the empirical treatment of nosocomial pneumonia.

Antibiotic prophylaxis with cefotaxime in gastroduodenal and biliary surgery

In a multicenter prospective, randomized study, the efficacy of a single preoperative dose of 1 g of cefotaxime for avoiding wound infections was compared with four 2-g doses of cefoxitin. In the study, 1,451 patients with infection risk factors who underwent gastroduodenal or biliary surgery were included, of whom 722 received cefotaxime and 729 cefoxitin. The characteristics of both groups were comparable. The frequency of wound infections in the cefotaxime group was 3.3 percent and in the cefoxitin group, 7.6 percent. The difference was statistically significant. The lowest rate of wound infection (0.63 percent) was achieved when cefotaxime was administered during the last hour before surgery. In both groups, the frequency of infections was directly related to the duration of operation. Hospital stay was, on average, 3 days longer in patients with wound infections. After cost-benefit analysis, we have concluded that cefotaxime treatment results in substantial reduction of costs derived from antibiotic prophylaxis.

The pharmacokinetics of ceftriaxone and cefotaxime in cirrhotic patients with ascites

We have compared in two separate studies the kinetics of ceftriaxone and cefotaxime in 8 cirrhotic patients with ascites and 8 control subjects after a single 20 min intravenous infusion of 1 g of each drug. The apparent volumes of distribution (Vz) were found to be significantly higher in cirrhotics than in control subjects (0.87, versus 0.49, l.kg-1, for cefotaxime and 0.23 versus 0.13 for ceftriaxone). The elimination kinetics of ceftriaxone were similar in the two groups. In contrast, the total and non-renal clearances of cefotaxime were reduced in cirrhotic patients. The two drugs rapidly entered the ascitic fluid. Peritoneal concentrations of ceftriaxone were higher than 7 micrograms.ml-1 from the second hour after the infusion and were 8.9 micrograms.ml-1 at 24 h. Peritoneal concentrations of cefotaxime were higher than 4 micrograms.ml-1 from 0.5 to 8 h after the infusion.

Antibacterial activity of cefotaxime, desacetylcefotaxime, and the combination of the two

Cefotaxime (CTX) is metabolized to desacetylcefotaxime (dCTX), which is antibacterially active. The combination of CTX and dCTX is synergistic in a 1:1 ratio, but in this study, a combination of CTX:dCTX in a fixed ratio of 5:1 was not found synergistic when tested on 120 recently isolated clinical strains. Zone diameters of disks containing pure CTX or dCTX 30 micrograms or the combination of CTX/dCTX in micrograms: 25/5, 20/10, 15/15, and 10/20, were compared. The correlation between the zone size of the pure CTX disk and the 25/5, 20/10, and 15/15 disks were high with correlation coefficients (r) 0.98 to 0.96. Regardless of the metabolism and the potential synergy, no differences were found in the zone sizes comparing the pure CTX disk with the combination with a ratio from 5:1 to 1:1. The clinical microbiological laboratory can go on using the pure 30 micrograms CTX disk for routine susceptibility testing.

Urinary alanine-aminopeptidase (AAP) excretion in patients with urinary tract infection treated with ceftazidime (CAZ) or cefotaxime (CTX) plus tobramycin (TOB)

It is well known that some antibiotics are particularly nephrotoxic. In the present study we investigated kidney function and AAP excretion (as an index of nephrotoxicity) in patients with urinary tract infection treated with CAZ or CTX plus TOB. The main cause of infection was E. coli in both treated groups. After 10 days of treatment similar beneficial effects were stated in both groups. At the end of treatment urinary AAP excretion in both groups was higher than before treatment. Despite a significant increase in urinary AAP in only one patient of each group, the serum creatinine level rose by more than 45 mumol/l. Monitoring of urinary AAP may be useful in early detection of nephrotoxicity caused by antibiotics.

An epidemic of pseudomembranous colitis: importance of person to person spread

Twenty three cases of pseudomembranous colitis (PMC) occurred in three hospitals in 10 months. Retrospective analysis shows that they represented a single epidemic with a readily traceable chain of person-to-person contact within and between hospitals. Most patients had severe pre-existing illness and all had broad spectrum antibiotics, including either ampicillin/amoxycillin, a broad spectrum cephalosporin (particularly cefotaxime), or both. All patients had severe diarrhoea and all responded to vancomycin, but relapse occurred in five. Ten patients eventually died, principally because of underlying disease rather than from PMC. Failure to find fibrin thrombi in blood vessels in biopsies and the scanty distribution of non-invasive bacteria supports the concept of mucosal damage by bacterial toxin, rather than by direct infection, or ischaemia. Although environmental colonisation cannot be excluded, the observed pattern of spread suggests a major role for direct person-to-person crossinfection in the spread of disease in this outbreak.

Cephalosporin, carbapenem, and monobactam antibiotics

Cephalosporin and related antibiotics are highly effective bactericidal agents of relatively low toxicity. The spectrum of activity varies with the drug but is usually broad. The first-generation cephalosporins, and especially cefazolin, are most active against sensitive staphylococci and streptococci. Most second-generation (except cefoxitin) and third-generation cephalosporins show substantial activity against Haemophilus influenzae. All cephalosporins (except cefsulodin) are active against Klebsiella, Escherichia coli, and Proteus mirabilis, whereas only the third-generation agents have pronounced activity against the other Enterobacteriaceae. Imipenem (a carbapenem) is active against essentially all pathogenic organisms, but aztreonam (a monobactam) is active against only aerobic gram-negative bacilli. Advantages associated with some of the new cephalosporins are once-daily administration and high cerebrospinal fluid levels. With the development of new cephalosporins, however, new toxicities have become apparent, and superinfections and induction of resistance have become greater problems. The cephalosporins are among the most expensive antibiotics in use today; thus, use of these expensive agents must be justified by lower toxicity, greater efficacy, or both in comparison with drugs of more reasonable cost.

Perioperative prophylaxis with sulbactam and ampicillin compared with metronidazole and cefotaxime in the prevention of wound infection in children undergoing appendectomy

Sulbactam is a beta-lactamase inhibitor, which when administered with ampicillin, increases the latter agents antibacterial activity against beta-lactamase producing organisms. One hundred children between the ages of 5 and 14 undergoing emergency appendectomy were entered into a prospective randomized trial comparing sulbactam and ampicillin (SA) with metronidazole and cefotaxime (MC) as prophylaxis against postoperative wound infection. Patients in whom the appendix was perforated or gangrenous received a 72-hour course of antibiotics, others received a single dose only. The overall wound infection rate was 8% (14% in patients with perforation or gangrene and 4% in those without). There was no difference in infection rate between the two antibiotic groups; there were three wound infections and one subphrenic abscess in patients receiving SA and four wound infections in patients receiving MC. SA, therefore, appears to be a suitable antibiotic combination for use as prophylaxis in appendicitis in children.