LAST UPDATED: June 2017
INSTRUCTIONS TO AUTHORS
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ASM strongly recommends that for clarity you use the past tense to narrate particular events in the past, including the procedures, observations, and data of the study that you are reporting. Use the present tense for your own general conclusions, the conclusions of previous researchers, and generally accepted facts. Thus, most of the abstract, Materials and Methods, and Results will be in the past tense, and most of the introduction and some of the Discussion will be in the present tense. Be aware that it may be necessary to vary the tense in a single sentence. For example, it is correct to say "White (30) demonstrated that XYZ cells grow at pH 6.8," "Figure 2 shows that ABC cells failed to grow at room temperature," and "Air was removed from the chamber and the mice died, which proves that mice require air." In reporting statistics and calculations, it is correct to say "The values for the ABC cells are statistically significant, indicating that the drug inhibited...." For an in-depth discussion of tense in scientific writing, see How To Write and Publish a Scientific Paper, 7th ed. General. Abbreviations should be used as an aid to the reader, rather than as a convenience to the author, and therefore their use should be limited. Abbreviations other than those recommended by the IUPAC-IUB (Biochemical Nomenclature and Related Documents, 1992) should be used only when a case can be made for necessity, such as in tables and figures. It is often possible to use pronouns or to paraphrase a long word after its first use (e.g., "the drug" or "the substrate"). Standard chemical symbols and trivial names or their symbols (folate, Ala, and Leu, etc.) may also be used. Define each abbreviation and introduce it in parentheses the first time it is used; e.g., "cultures were grown in Eagle minimal essential medium (MEM)." Generally, eliminate abbreviations that are not used at least three times in the text (including tables and figure legends). Not requiring introduction. In addition to abbreviations for Système International d'Unités (SI) units of measurement, other common units (e.g., bp, kb, and Da), and chemical symbols for the elements, the following should be used without definition in the title, abstract, text, figure legends, and tables:
Abbreviations for cell lines (e.g., HeLa) also need not be defined. The following abbreviations should be used without definition in tables:
Drugs and pharmaceutical agents. Should an author decide to abbreviate the names of antimicrobial agents in a manuscript, the following standard abbreviations are strongly recommended. (i) Antibacterial agents. Use the indicated abbreviations for the following antibacterial agents.
(ii) β-Lactamase inhibitors. Use the indicated abbreviations for the following β-lactamase inhibitors.
(iii) Antifungal agents. Use the indicated abbreviations for the following antifungal agents.
(iv) Antiviral agents. Use the indicated abbreviations for the following antiviral agents (for additional agents, refer to Table 2 in De Clercq and Li, Clin Microbiol Rev 29:695-747, 2016 [https://doi.org/10.1128/CMR.00102-15]).
(v) Antimycobacterial agents. Use the indicated abbreviations for the following antimycobacterial agents.
The use of "nonstandard" abbreviations to designate names of antibiotics and other pharmaceutical agents generally will not be accepted, because the use of different abbreviations for a single agent has often caused confusion. If, on occasion, a nonstandardized abbreviation for a drug or pharmaceutical substance is used, it will be accepted under the following conditions: (i) it must be defined at the first use in the text, (ii) it must be unambiguous in meaning, and (iii) it must contribute to ease of assimilation by readers. Chemical or generic names of drugs should be used; the use of trade names is not permitted. Avoid the ambiguous term “generation” when classes of drugs are described. When code names or corporate proprietary numbers are to be used, either the chemical structure of the compound or a published literature reference illustrating the chemical structure, if known, must be provided at the first occurrence of the code name or number. For compounds not identified by generic nomenclature, all previous or concurrent identification numbers or appellations should be listed in the manuscript. Pharmacodynamic terminology. Pharmacodynamic indices (PDIs) must be introduced at their first occurrence in the text and follow guidelines set forth by Mouton et al. (J Antimicrob Chemother 55:601-607, 2005). In Materials and Methods, it should be clearly stated how the PDIs were derived. The most common indices used are the following: AUC/MIC ratio (the area under the concentration-time curve over 24 h in steady state divided by the MIC), AUIC (the area under the inhibitory curve; note that the AUC/MIC ratio is not equal to the AUIC), %TMIC (the cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions), Cmax/MIC ratio (the peak level divided by the MIC), PTA (probability of target attainment), and CFR (cumulative fraction of response). Clear distinction should be made between %TMIC, which is expressed as a percentage of the dosing interval, and TMIC, expressed in hours. It is strongly recommended that the prefix f be used with an index (e.g., fAUC) if the free, unbound fraction of the drug is meant. Studies performed to characterize a β-lactamase or the interaction of a compound with a β-lactamase (i.e., as a substrate, inhibitor, or inducer) should follow the guidelines set forth by Bush and Sykes (Antimicrob Agents Chemother 30:6-10, 1986). Assays that measure the hydrolysis of β-lactam antibiotics must be appropriate for the substrate examined (e.g., iodometric methods are not appropriate quantitative assays for substrates whose products are unknown). Reproducibility of results must be shown. When referring to β-lactamases, please use the functional designations defined by Bush and Jacoby (Antimicrob Agents Chemother 54:969-976, 2010). Alternatively, if the amino acid sequence for the enzyme is known, the β-lactamases may be described by molecular class as initiated by Ambler (Philos Trans R Soc Lond B Biol Sci 289:321-331, 1980). A database of defining amino acid alterations for many β-lactamases is maintained at https://www.ncbi.nlm.nih.gov/projects/pathogens/submit_beta_lactamase/. The managers of that site should be consulted about the name of a potentially novel β-lactamase sequence before a new designation or number is proposed for publication. Tabulate results of determinations of minimal inhibitory and bactericidal concentrations according to the range of concentrations of each antimicrobial agent required to inhibit or kill the members of a species or of each group of microorganisms tested, as well as the corresponding concentrations required to inhibit 50 and 90% of the strains (MIC50 and MIC90, respectively) and those required to kill 50 and 90% of the strains (MBC50 and MBC90, respectively). Geometric mean MICs may also be reported when relevant. The MIC50 and MIC90 reported should be the actual concentrations tested that inhibited 50 and 90%, respectively, of the strains. They should not be values calculated from the actual data obtained. When only six to nine isolates of a species are tested, tabulate only the MIC range of each antimicrobial agent tested. If more than a single drug is studied, insert a column labeled "Test agent" between the columns listing the organisms and the columns containing the numerical data and record data for each agent in the same isolate order. Cumulative displays of MICs or MBCs in tables or figures are acceptable only under unusual circumstances. The percentage of strains susceptible and/or resistant to an antibiotic at its breakpoint concentration may be given only if an appropriate breakpoint has been approved, as by the Clinical and Laboratory Standards Institute (http://clsi.org/). In the absence of approved breakpoints, authors cannot assign breakpoints or use breakpoints from related antibiotics. An exploratory analysis tabulating the percentage of strains inhibited over a range of concentrations is acceptable. Bactericidal tests must be performed with a sufficient inoculum (>5 x 105 CFU/ml) and subculture volume (0.01 ml) to ensure accurate determination of the 99.9% killing endpoint, as described by Pearson et al. (Antimicrob Agents Chemother 18:699-708, 1980) and Taylor et al. (Antimicrob Agents Chemother 23:142-150, 1983). Inoculum size and subculture volume are also critical to studies of combinations of antimicrobial agents. Synergy is defined in two-dimensional or checkerboard tests when the fractional inhibitory concentration (FIC) or fractional
bactericidal concentration (FBC) index ( When standard twofold-dilution schemes are used to determine checkerboard interactions, the inherent variability of the method
casts doubt on the significance of interactions represented by For killing curve tests, the minimal, accurately countable number of CFU per milliliter must be stated and the method used for determining this number must be described. In the absence of any drug and with a sample size of 1 ml, this number is 30 (1.5 in log10) CFU. If procedures for drug inactivation or removal have not been performed, the author must state how drug carryover effects were eliminated or quantified. For drugs showing an inoculum effect, mere dilution below the MIC obtained in standard tests is not sufficient. (i) Registration. AAC requires the prospective registration (i.e., before the first patient is enrolled) of a clinical trial in a public trials registry in accordance with guidelines established by the International Committee of Medical Journal Editors (ICMJE) (http://www.icmje.org/recommendations/browse/publishing-and-editorial-issues/clinical-trial-registration.html). The ICMJE defines a clinical trial as “any research project that prospectively assigns people or a group of people to an intervention, with or without concurrent comparison or control groups, to study the cause-and-effect relationship between a health-related intervention and a health outcome.” AAC does not require registration in a particular registry, but the registry chosen must meet the following criteria, in agreement with ICMJE recommendations. It must be (a) accessible to the public free of charge, (b) open to all registrants, (c) managed by a not-for-profit organization, (d) monitored by a mechanism to ensure validity of registration data, and (e) searchable electronically. A registration with missing fields or uninformative terminology will be deemed inadequate. The registry and the trial registration number must be included at the end of the abstract. If a registration number is available, the authors should state this number the first time a trial acronym is used to refer to the trial being reported or to other trials mentioned in the manuscript. (ii) Criteria for enrollment. The methods used to find and enroll patients and the criteria for enrollment in a clinical trial should be stated. In addition, the time period (month/year to month/year) of the enrollment should be specified. It should be indicated, if appropriate, that written informed consent was obtained and that the trial was approved by the pertinent committee on human subjects. (iii) Method of randomization. Randomized, double-blind studies are preferred. Comparisons using historical controls are usually regarded as questionable unless the differences in outcome between the groups are dramatic and almost certainly the result of the new intervention. The rationale for the choice of the control group should be explained. The sample size should be justified, and the method of randomization should be stated. (vi) Criteria for determining whether a case is evaluable. The minimum criteria for evaluability should be stated explicitly. For example, it should be stated that the minimum criterion for evaluability was a or the combination of b and c rather than a, b, and c without designating which were the minimum criteria. The criteria for evaluability are usually different from those for enrollment. (v) Reasons for nonevaluability. State the number of patients in each group who were excluded from evaluation and the reason(s) for each exclusion. (vi) Criteria for assessment. Define each outcome for each category of assessment (e.g., "clinical outcomes were classified as cure, improvement, and failure; microbiological outcomes were classified as eradication, persistence, and relapse"). The frequency and timing of such assessments in relation to treatment should be stated. Specify any changes made in the study regimen(s) during the trial; the results for regimens with and without such modification generally should be stated separately. The criteria (questionnaires, results of specific laboratory tests) for evaluation of adverse effects should be stated, as should the period encompassed in the assessment and the time of assessment in relation to the time of treatment (e.g., daily during treatment). Some authors prefer to consider superinfections as failures of treatment, whereas others prefer to consider them separately or even as adverse effects. In any event, the manuscript should state the number of superinfections with each regimen and should differentiate between superinfections and colonization. The duration of follow-up should be mentioned. (vii) Statistical analyses. The type of statistical test should be stated, and when appropriate, the reason for the choice of test should be given. References should be given for statistical procedures other than the t test, chi-square test, and Wilcoxon rank sum test. The comparability of the treatment groups at the baseline should be evaluated statistically. For a review of some common errors associated with statistical analyses and reports, plus guidelines on how to avoid them, see the articles by Olsen (Infect Immun 71:6689-6692, 2003; Infect Immun 82:916–920, 2014). For a review of basic statistical considerations for virology experiments, see the article by Richardson and Overbaugh (J Virol 79:669-676, 2005). (viii) Beta error. For trials which show no statistically significant difference between regimens, calculate the probability (β) of a type II error and the power of the study (1 – β) to detect a specified clinically meaningful difference in efficacy between the regimens. For further details, see the article by Freiman et al. (N Engl J Med 299:690-694, 1978). Alternatively, or in addition, indicate the magnitude of difference between the regimens that could have been detected at a statistically significant level with the number of evaluable patients studied. For further details, see the editorial on guidelines for clinical trials (Antimicrob Agents Chemother 33:1829-1830, 1989). Standard metric units are used for reporting length, weight, and volume. For these units and for molarity, use the prefixes m, µ, n, and p for 10–3, 10–6, 10–9, and 10–12, respectively. Likewise, use the prefix k for 103. Avoid compound prefixes such as mµ or µµ. Use µg/ml or µg/g in place of the ambiguous ppm. Units of temperature are presented as follows: 37°C or 324 K. When fractions are used to express units such as enzymatic activities, it is preferable to use whole units, such as g or min, in the denominator instead of fractional or multiple units, such as µg or 10 min. For example, “pmol/min” is preferable to “nmol/10 min,” and “µmol/g” is preferable to “nmol/µg.” It is also preferable that an unambiguous form, such as exponential notation, be used; for example, “µmol g–1 min–1” is preferable to “µmol/g/min.” Always report numerical data in the appropriate SI units. Representation of data as accurate to more than two significant figures must be justified by presentation of appropriate statistical analyses. For a review of some common errors associated with statistical analyses and reports, plus guidelines on how to avoid them, see the articles by Olsen (Infect Immun 71:6689-6692, 2003; Infect Immun 82:916-920, 2014). For a review of basic statistical considerations for virology experiments, see the article by Richardson and Overbaugh (J Virol 79:669-676, 2005). Isotopically Labeled Compounds For simple molecules, labeling is indicated in the chemical formula (e.g., 14CO2, 3H2O, and H235SO4). Brackets are not used when the isotopic symbol is attached to the name of a compound that in its natural state does not contain the element (e.g., 32S-ATP) or to a word that is not a specific chemical name (e.g., 131I-labeled protein, 14C-amino acids, and 3H-ligands). For specific chemicals, the symbol for the isotope introduced is placed in square brackets directly preceding the part of the name that describes the labeled entity. Note that configuration symbols and modifiers precede the isotopic symbol. The following examples illustrate correct usage: [14C]urea L-[methyl-14C]methionine [2,3-3H]serine [ [ UDP-[U-14C]glucose E. coli [32P]DNA fructose 1,6-[1-32P]bisphosphate |
) is 
0.5. In killing curves, synergy is defined as a 
2-log
FIC or 
FBC of >4.0.
FICs or 
FBCs of >0.5 but 
4. Therefore, such interactions, if labeled at all, should be termed “indifferent.” Alternatively, indices in this range may
be described as “nonsynergistic” or “nonantagonistic,” as appropriate. The technically imprecise term “additive” should be
avoided, as it is too easily misunderstood. See reports by W. R. Greco et al. (Pharmacol Rev 47:331-385, 1995), F. C. Odds
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