"Early withdrawal from mental health treatment: Implications for psychotherapy practice": Correction to Barrett et al (2008).

Reports an error in "Early withdrawal from mental health treatment: Implications for psychotherapy practice" by Marna S. Barrett, Wee-Jhong Chua, Paul Crits-Christoph, Mary Beth Gibbons and Don Thompson (Psychotherapy: Theory, Research, Practice, Training, 2008[Jun], Vol 45[2], 247-267). The fourth author's name was mistakenly left out of the author byline and table of contents. The correct author listing for this article is presented in the erratum. (The following abstract of the original article appeared in record 2008-07317-011.) Despite more than 50 years of research on client attrition from therapy, obstacles to the delivery and success of treatments remain poorly understood, and effective methods to engage and retain clients in therapy are lacking. This article offers a review of the literature on attrition, highlighting the methodological challenges in effectively addressing the complex nature of this problem. Current interventions for reducing attrition are reviewed, and recommendations for implementing these interventions into psychotherapy practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Heating and humidifying of carbon dioxide during pneumoperitoneum is not indicated: a prospective randomized trial.

BACKGROUND: Carbon dioxide (CO2) pneumoperitoneum usually is created by a compressed gas source. This exposes the patient to cool dry gas delivered at room temperature (21 degrees C) with 0% relative humidity. Various delivery methods are available for humidifying and heating CO2 gas. This study was designed to determine the effects of heating and humidifying gas for the intraabdominal environment. METHODS: For this study, 44 patients undergoing laparoscopic Roux-en-Y gastric bypass were randomly assigned to one of four arms in a prospective, randomized, single-blinded fashion: raw CO2 (group 1), heated CO2 (group 2), humidified CO2 (group 3), and heated and humidified CO2 (group 4). A commercially available CO2 heater-humidifier was used. Core temperatures, intraabdominal humidity, perioperative data, and postoperative outcomes were monitored. Peritoneal biopsies were taken in each group at the beginning and end of the case. Biopsies were subjected staining protocols designed to identify structural damage and macrophage activity. Postoperative narcotic use, pain scale scores, recovery room time, and length of hospital stay were recorded. One-way analysis of variance (ANOVA) and the nonparametric Kruskal-Wallis test were used to compare the groups. RESULTS: Demographics, volume of CO2 used, intraabdominal humidity, bladder temperatures, lens fogging, and operative times were not significantly different between the groups. Core temperatures were stable, and intraabdominal humidity measurements approached 100% for all the patients over the entire procedure. Total narcotic dosage and pain scale scores were not statistically different. Recovery room times and length of hospital stay were similar in all the groups. Only one biopsy in the heated-humidified group showed an increase in macrophage activity. CONCLUSIONS: The intraabdominal environment in terms of temperature and humidity was similar in all the groups. There was no significant difference in the intraoperative body temperatures or the postoperative variable measured. No histologic changes were identified. Heating or humidifying of CO2 is not justified for patients undergoing laparoscopic bariatric surgery.

Is psychotherapy more effective when therapists disclose information about themselves?

Theorists have long debated the wisdom of therapists disclosing personal information during psychotherapy. Some observers have argued that such therapist self-disclosure impedes treatment, whereas others have suggested that it enhances the effectiveness of therapy. To test these competing positions, therapists at a university counseling center were instructed to increase the number of self-disclosures they made during treatment of one client and refrain from making self-disclosures during treatment of another client. Analyses revealed that clients receiving psychotherapy under conditions of heightened therapist disclosure not only reported lower levels of symptom distress but also liked their therapist more. Such findings suggest that self-disclosure by the therapist may improve both the quality of the therapeutic relationship and the outcome of treatment.

Anti-gonococcal activity of gemifloxacin against fluoroquinolone-resistant strains and a comparison of agar dilution and Etest methods.

Gemifloxacin is a novel quinolone with excellent activity against Gram-positive and some Gram-negative pathogens. Its activity was tested against 150 Neisseria gonorrhoeae strains, including 50 ciprofloxacin-resistant isolates, using reference agar dilution and Etest methods. Gemifloxacin was found to be highly potent against ciprofloxacin-susceptible strains (MIC(90) 0.008 mg/L), but was 16-fold less potent against ciprofloxacin-resistant gonococci. The order of quinolone potency against these fluoroquinolone-resistant mutants was: gemifloxacin (MIC(90) 0.12 mg/L) > trovafloxacin (0.25 mg/L) > moxifloxacin = grepafloxacin (0.5 mg/L) > ciprofloxacin (1 mg/L). Etest and reference agar dilution MIC results showed excellent correlation (r = 0.96) and >98% of MICs were within +/-1 log(2) dilution step (essential agreement). The excellent potency of gemifloxacin indicates its potential for the treatment of infections with quinolone-resistant N. gonorrhoeae.

Comparative antimicrobial activity of gatifloxacin tested against Campylobacter jejuni including fluoroquinolone-resistant clinical isolates.

Campylobacter jejuni is an important pathogen that causes gastroenteritis, as well as other disease states such as meningitis and septic arthritis. In this study, the Etest (AB BIODISK, Solna, Sweden) results were compared to a reference agar dilution method using gatifloxacin, a new 8-methoxyfluoroquinolone. A total of 53 strains of C. jejuni initially isolated from patients in California and Mexico were tested. Results demonstrated a high correlation (r = 0.88) between the two utilized in vitro dilution methods. In addition, gatifloxacin activity was compared to that of ciprofloxacin, metronidazole, amoxicillin, erythromycin, chloramphenicol, gentamicin, tetracycline, and trimethoprim/sulfamethoxazole using the Etest. Gatifloxacin (MIC90, 4 micrograms/ml) was approximately eight- to 16-fold more potent than ciprofloxacin (Mic90, > 32 micrograms/ml), a commonly used fluoroquinolone for Campylobacter infections. Eight strains highly resistant to ciprofloxacin (MIC90, > 32 micrograms/ml) were tested for cross resistance against the newer fluoroquinolones (gatifloxacin, levofloxacin, trovafloxacin) and the rank order of potency was: gatifloxacin (MIC50, 16 micrograms/ml) > trovafloxacin = levofloxacin (MIC50, > 32 micrograms/mL). However, only 25% ciprofloxacin-resistant strains were inhibited by < or = 1 microgram/mL of gatifloxacin or trovafloxacin. These results for gatifloxacin against C. jejuni strains must be further assessed in the context of in vivo trials before the clinical role of this new fluoroquinolone can be determined. The Etest appears to be a simple and precise susceptibility test method for testing C. jejuni isolates against fluoroquinolones and other alternative therapeutic agents.

Comparative in vitro evaluation of dirithromycin tested against recent clinical isolates of Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae, including effects of medium supplements and test conditions on MIC results.

The use of macrolides for treatment of respiratory complaints has been complicated by susceptibility test conditions that adversely effect the in vitro test results and perceived potencies of these compounds. Dirithromycin was studied as to its in vitro activity compared to other macrolides as well as the effects that environmental incubation variations and inoculum concentrations may have on susceptibility results. Dirithromycin was less active than other macrolides tested (azithromycin clarithromycin, erythromycin) against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis with MIC90 values of 16, 32, and 1 microgram/ml, respectively; an activity that was most similar to roxithromycin. This reduced activity may be compensated by the superior pharmacokinetic properties that dirithromycin possesses compared to other members in its class. Method variation studies show that incubation in CO2 environments increase the MIC values for all macrolide compounds and dirithromycin was most effected by pH changes in three in vitro methods tested (Etest [AB BIODISK, Solna, Sweden] broth microdilution, and disk diffusion). Variations in inoculum concentration had minimal effect on dirithromycin potency. In addition the variability (lack of reproducibility) of the test results with dirithromycin were not significant. Dirithromycin is an alternative therapeutic choice among macrolide compounds for treatment of community-acquired respiratory infections caused by various streptococci, Legionella pneumophilia, Mycoplasma pneumoniae and M. catarrhalis, and also possesses a modest in vitro potency versus H. influenzae coupled with excellent pharmacokinetic properties. In vitro tests with dirithromycin will continue to be problematic for H. influenzae because of the adverse effects of recommended CO2 incubation for some standardized methods or commercial products (Etest).

BAY 12-8039, a novel fluoroquinolone. Activity against important respiratory tract pathogens.

BAY 12-8039 or moxifloxacin is a new 8-methoxyquinolone with documented, improved activity against Gram-positive cocci and anaerobic bacteria. This study tested 1250 commonly isolated respiratory tract pathogens (251 Moraxella catarrhalis, 499 Haemophilus influenzae, 500 Streptococcus pneumoniae) from 1996-1997 clinical infections at more than 30 medical centers. Among the M. catarrhalis strains (81% beta-lactamase-positive) the BAY 12-8039 MIC90 was 0.06 microgram/mL, a potency equal to ofloxacin but less than all other tested fluoroquinolones (ciprofloxacin, clinafloxacin, levofloxacin, sparfloxacin, trovafloxacin). The H. influenzae strains were generally less susceptible to BAY 12-8039 (MIC90, 0.03 microgram/mL) than the tested fluoroquinolones, and the other comparison compounds were less active overall. All S. pneumoniae strains were susceptible to BAY 12-8039 at < or = 0.25 microgram/mL (MIC90, 0.06-0.12 microgram/mL), a value equal-potent to trovafloxacin. This new fluoroquinolone, BAY 12-8039, appears promising for the treatment of community-acquired respiratory tract infections caused by common bacterial species.

In vitro evaluation of a novel orally administered cephalosporin (Cefditoren) tested against 1249 recent clinical isolates of Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae.

Cefditoren (formerly ME-1206), a new orally administered cephalosporin, was evaluated in vitro against 1249 recently isolated strains of Streptococcus pneumoniae (500 strains), Moraxella catarrhalis (250 strains), and Haemophilus influenzae (499 strains). Reference National Committee for Clinical Laboratory Standards methods were used and the strains were representative for the current rates of beta-lactamase production or penicillin resistance. Cefditoren had MIC50/MIC90 results for Moraxella catarrhalis and Haemophilus influenzae of 0.12/0.5 and < or = 0.008/0.015 microgram/mL, respectively. The pneumococci were consistently twofold to eightfold more susceptible to cefditoren than other oral cephalosporins or penicillins. The MIC90 for penicillin-resistant S. pneumoniae was only 2 micrograms cefditoren/mL, and the highest recorded MIC was 4 micrograms/mL. Cefditoren appears to be a very promising beta-lactam possessing the greatest potency and potential spectrum versus contemporary (1997) respiratory tract pathogens.

Comparative antimicrobial activity and kill-curve investigations of novel ketolide antimicrobial agents (HMR 3004 and HMR 3647) tested against Haemophilus influenzae and Moraxella catarrhalis strains.

The activity of two ketolide compounds, HMR 3004 and 3647, were compared to those of five macrolides, quinupristin/dalfopristin, ciprofloxacin, and ampicillin. The rate of killing for the ketolides was also assessed against Haemophilus influenzae and Moraxella catarrhalis. One hundred H. influenzae and 148 M. catarrhalis isolates were tested using broth microdilution and appropriate growth media. The killing rates of HMR 3004 and 3647 were analyzed using the time-kill method against five strains from each of the two species. Against H. influenzae, the activity of the ketolides (MIC90, 2 or 4 microg/mL) resembled that of azithromycin and quinupristin/dalfopristin and was more active than any tested macrolide. Against M. catarrhalis, HMR 3004 and 3647 were equally potent as azithromycin and clarithromycin (MIC50, 0.06 microg/mL and MIC90, 0.12 microg/mL) and more potent than all other macrolides or quinupristin/dalfopristin. Time-kill kinetic studies revealed that like the macrolide compounds, the ketolides are bacteristatic at or near the MIC for both H. influenzae and M. catarrhalis. This activity can be increased to a bactericidal level if the concentration is increased four- or eightfold the MIC for H. influenzae. In conclusion, HMR 3004 and 3647 have bacteristatic activity against tested respiratory pathogens and may prove to have an important role against macrolide-resistant isolates.

Timed kill kinetic studies of levofloxacin, ofloxacin, and ciprofloxacin against Moraxella catarrhalis.

Levofloxacin bactericidal activity was compared to ciprofloxacin and ofloxacin against 10 strains of Moraxella catarrhalis. The cidal action (by kill-curve analysis) was slightly more rapid for levofloxacin, but all tested fluoroquinolones were considered bactericidal for all strains tested, including those producing BRO-1 and 2 beta-lactamases.

Application of the Etest to the antimicrobial susceptibility testing of Mycobacterium marinum clinical isolates.

Mycobacterium marinum, a well-recognized cutaneous pathogen, is usually treated by chemotherapy without available standardized in vitro susceptibility testing information. In this study, we have attempted to apply the stable-gradient method (Etest; AB Biodisk, Solna, Sweden) to susceptibility testing of M. marinum in order to assess the activities of eight antimicrobial agents against 60 recent clinical strains of M. marinum collected from 10 geographic sites within the United States. Two plated media (5% sheep blood Mueller-Hinton agar and Middlebrook 7H11 agar) were compared, and 7H11 agar was found to be superior in supporting the growth of all strains. Four reference strains of M. marinum were tested on five occasions with eight drugs (160 tests) in order to evaluate Etest reproducibility. Results were observed to be within 1 log2 dilution of the all-test median MIC for 97.5% of the Etests. Our MIC results for the 60 strains clearly demonstrate the best in vitro potency against M. marinum isolates to be as follows (rank order): trimethoprim-sulfamethoxazole (MIC at which 90% of the isolates are inhibited [MIC90], 0.25 and 4.25 microg/ml, respectively) = ethambutol > clarithromycin (MIC90, 1 microg/ml) > minocycline = doycycline (MIC90, 4 microg/ml) > amikacin (MIC90, 8 microg/ml). Rifampin was only marginally active against the M. marinum strains tested (MIC90, at the National Committee for Clinical Laboratory Standards) breakpoint of 1 microg/ml), and ciprofloxacin was not active (MIC90, 8 microg/ml). These data should enhance the empiric drug selection for contemporary M. marinum infections and also provide evidence that the Etest can be utilized to guide chemotherapy with alternative agents.

Antimicrobial activity of trovafloxacin tested against ciprofloxacin-susceptible and -resistant Neisseria gonorrhoeae. Interpretive criteria and comparisons with Etest results.

Trovafloxacin, a new fluorinated naphthyridine, has enhanced activity against Gram-positive cocci, while retaining an excellent spectrum against Gram-negative pathogens. It has been used successfully in clinical trials for therapy of gonorrhea, and this investigation proposes in vitro susceptibility testing criteria for trovafloxacin. A total of 150 Neisseria gonorrhoeae clinical isolates (50 resistant to ciprofloxacin; MICs > or = 0.12 microgram/mL) were tested by methods recommended by the National Committee for Clinical Laboratory Standards (NCCLS) and the Etest (AB BIODISK, Solna, Sweden). Trovafloxacin was very active against gonococci (MIC90, 0.008 to 0.015 microgram/mL), but was generally eightfold less potent versus ciprofloxacin-resistant strains. Etest results correlated well (r = 0.96; 98% of MICs +/- one log2 dilution) compared to the reference agar dilution test. Reference agar dilution and Etest MICs were compared to disk-diffusion test zones (10-micrograms trovafloxacin disk), and excellent categorical agreement (89.4 to 99.3%) was achieved without significant false-susceptible or -resistant error (< or = 1.3%). Tentative breakpoints were suggested initially to outline the ciprofloxacin-susceptible and trovafloxacin-susceptible as susceptible (MIC, < or = 0.015 microgram/mL; zones > or = 47 mm), and strains with various well-characterized mutations of the gyr A and par C genes as either intermediate or resistant to trovafloxacin. When the results of clinical studies treating ciprofloxacin-resistant N. gonorrhoeae with trovafloxacin become available, the alternative breakpoints could be utilized for resistant MIC breakpoints of > or = 0.06 microgram/mL or > or = 0.5 microgram/mL. Trovafloxacin was stable in supplemented GC agar for 21 days stored at refrigerated temperatures. These in vitro results indicate that trovafloxacin should be a very acceptable agent for therapy of gonorrhea and other common sexually transmitted pathogens.

Antimicrobial characteristics of quinupristin/dalfopristin (Synercid at 30:70 ratio) compared to alternative ratios for in vitro testing.

Quinupristin/dalfopristin is a new streptogramin combination that occurs at a natural ratio and formulation of 30:70. Rapid metabolism of the dalfopristin component to RP 12536 in vivo puts in question the validity of in vitro test of spectrum with the parent combination. In studies of quinupristin with both dalfopristin and RP 12536, a wide range of ratios (30:70, 50:50, 70:30) were tested by reference MIC and MBC tests. No significant potency differences were observed between combination ratios or metabolic components when testing 256 bacterial strains. Quinupristin/dalfopristin or quinupristin/RP 12536 remained active, by bactericidal action against many staphylococci and Streptococcus ssp. Enterococcus faecium strains were susceptible (MIC90, 2 micrograms/ml; static effect only) to the streptogramin, but E. faecalis, Pasteurella multocida, Pediococcus ssp., Haemophilus influenzae, and Bacteroides fragilis were generally less susceptible (MIC90, > or = 8 micrograms/ml). The log phase inoculum was preferred for MBC and kill-curve tests with this combination. The 30:70 ratio in vitro susceptibility test of quinupristin/dalfopristin as used to date, seems to predict the potency and spectrum of this streptogramin accurately and all clinically important in vivo ratios of the injectable form or its major metabolites. Quinupristin/dalfopristin should be further investigated for clinical use against emerging resistant Gram-positive infections, especially penicillin-resistant streptococci and glycopeptide-resistant E. faecium that exhibit susceptibility in this investigation.

In vitro activity and spectrum of LY333328, a novel glycopeptide derivative.

Reference methods were used to determine the potency of LY333328, a semisynthetic glycopeptide derivative with a key N-alkylation substitution, against 833 strains (393 gram-positive strains and representative gram-negative bacilli) with various defined resistance mechanisms. The MICs at which 90% of the isolates are inhibited (MIC90S) (in micrograms per milliliter) of LY333328 and the percentages of strains at < or = 8 micrograms/ml were as follows: for oxacillin-susceptible Staphylococcus aureus, 2 and 100%, and for oxacillin-resistant Staphylococcus aureus, 4 and 100%; for oxacillin-susceptible Staphylococcus epidermis, 4 and 100%, and for oxacillin-resistant Staphylococcus aureus, 8 and 96%; for Streptococcus serogroups A, B, C, and G, 0.25 to 1 and 100%; for Streptococcus pneumoniae < or = 0.015 to 0.06 and 100%; for Enterococcus faecalis, 2 and 100%; and for vancomycin-susceptible Enterococcus faecium, 0.25 and 100%, and for vancomycin-resistant Enterococcus faecium, 4 and 100%. LY333328 was not active (MIC50, > or = 16 micrograms/ml) against more than 400 representative strains of Enterobacteriaceae, pseudomonads, Acinetobacter spp., Stenotrophomonas maltophilia, Haemophilus influenzae, Moraxella catarrhalis, pathogenic Neisseria spp., and anaerobic gram-negative bacilli. Gram-positive anaerobes were LY333328 susceptible (MICs, < or = 2 micrograms/ml). Test methods and conditions may have affected MICs of LY333328, with most (species variation) agar dilution MICs being greater than the broth microdilution MICs.

Phenotypic detection of mec A-positive staphylococcal blood stream isolates: high accuracy of simple disk diffusion tests.

Detection of oxacillin-resistance in staphylococci by phenotypic methods remains problematic. Although standardized susceptibility test methods are adequate for Staphylococcus aureus, many are less satisfactory for the coagulase-negative staphylococci (CNS). We have studied 108 consecutive blood culture isolates of staphylococci. The mec A gene was detected by PCR in one S. aureus and 55 CNS isolates. Susceptibility testing was performed as follows: oxacillin (1-microgram), ceftizoxime (30-microgram), and cephalothin (30-microgram) by disk diffusion; oxacillin, ceftizoxime, cephalothin, methicillin, ampicillin, ampicillin/ sulbactam, penicillin, cefazolin, imipenem, and meropenem by the broth microdilution method. In addition, isolates were tested by the oxacillin agar screen plate method. The single oxacillin-resistant S. aureus strain was detected by all oxacillin susceptibility test methods and by the ceftizoxime disk and MIC methods. Two oxacillin-susceptible S. aureus were intermediate (minor error) by ceftizoxime broth microdilution (MIC, 16 micrograms/mL). The most sensitive, simple phenotypic methods for detection of oxacillin-resistant CNS (mec A positive) were as follows: oxacillin disk diffusion at 98%, oxacillin screen plate at 91%, oxacillin broth microdilution at 87%, ceftizoxime disk diffusion at 100%, ceftizoxime broth microdilution at 87%, and methicillin broth microdilution at 83%. These results indicate that oxacillin and ceftizoxime disk diffusion tests are the most accurate phenotypic methods in routine clinical use for detection of oxacillin-resistant CNS. Oxacillin broth microdilution MIC testing (2% NaCl supplement) would perform more satisfactorily (100% sensitivity) with an adjusted interpretive breakpoint at < or = 0.5 microgram/mL, in contrast to the lower accuracy of the "so-called" reference agar screen test.

In vitro activity of quinupristin/dalfopristin (RP 59500) against a large collection of infrequently isolated or tested species.

Quinupristin/dalfopristin (RP 59500, Synercid) is a parenteral streptogramin combination antimicrobial that possesses a synergistic and often bactericidal action against many Grampositive species. In this study, a collection of 1270 uncommonly isolated or tested strains were evaluated for susceptibility to quinupristin/dalfopristin using agar dilution minimum inhibitory concentration (MIC) methods described in the National Committe for Clinical Laboratory Standards. The greatest antimicrobial activity observed for quinupristin/dalfopristin was against staphylococci, streptococci, the pathogenic neisseria, Legionella spp., Lactobacillus spp., and Peptostreptococcus spp. (MIC90 range, 0.5-2 micrograms/ml). Marginal activity (MIC90s, 4 to 8 micrograms/ml) was identified for the rarer enterococci, Leuconostoc spp., Pediococcus spp., and Streptococcus bovis. Against Haemophilus parainfluenzae, Bacteroides thetaiotaomicron, Fusobacterium spp., and Prevotella spp., the streptogramin was inactive. Although no susceptible breakpoint has been approved for quinupristin/dalfopristin, three possible breakpoints (< or = 1, < or = 2, or < or = 4 micrograms/mL) were evaluated. Acceptance of the lower breakpoints (< or = 1 or < or = 2 micrograms/mL) would limit quinupristin/dalfopristin use to staphylococci, streptococci, gonococci, meningococci, and Legionella spp. These results markedly expand the understanding of the usable spectrum of quinupristin/dalfopristin.

Unilateral pudendal neuropathy. Significance and implications.

PURPOSE: Obstetric trauma and excessive defecatory straining with perineal descent may lead to pudendal neuropathy with bilateral increase in pudendal nerve terminal motor latencies (PNTML). We have frequently observed unilateral prolongation of PNTML. Diagnostic and therapeutic implications of unilateral pudendal neuropathy are discussed. METHODS: Records of 174 patients referred to pelvic floor laboratory for anorectal manometry and PNTML testing were reviewed. Computerized and manometry was performed using dynamic pressure analysis, and PNTML was determined using a pudendal (St. Mark's) electrode. RESULTS: No response was elicited from pudendal nerves to electric stimulation from both sides in 14 patients (8 percent) and from one side in 24 patients (13.8 percent). Bilateral PNTML determination was possible in only 136 patients (78 percent), of whom 83 patients (61 percent) had no evidence of neuropathy, revealing normal PNTML on both sides. Of 53 patients (39 percent) with delayed conduction in pudendal nerves, in 15 patients (28 percent), PNTML was abnormally prolonged on both sides, with an abnormal mean value for PNTML. In the remaining 38 patients (72 percent), PNTML was abnormal on one side; in 27 patients with an abnormal mean PNTML and in 11 patients with a normal mean PNTML. CONCLUSIONS: A significant number of patients with pelvic floor disorders have only unilateral pudendal neuropathy. Patients with unilaterally prolonged PNTML should be considered to have pudendal neuropathy, despite normal value for mean PNTML. This fact may be relevant in planning surgical treatment and in predicting prognosis of patients with sphincter injuries.

Evaluation of in vitro spectra of activity of azithromycin, clarithromycin, and erythromycin tested against strains of Neisseria gonorrhoeae by reference agar dilution, disk diffusion, and Etest methods.

The macrolide-azilide susceptibility testing (agar dilution, disk diffusion, Etest) criteria for 105 Neisseria gonorrhoeae strains were evaluated. In addition, the potencies of azithromycin, clarithromycin, and erythromycin were studied. The most active macrolide-azilide agent was azithromycin (MIC at which 90% of the isolates are inhibited [MIC90], 0.5 microgram/ml) compared with clarithromycin (MIC90, 1.5 to 2 micrograms/ml) and erythromycin (MIC90, 2 to 4 micrograms/ml). The Etest (AB Biodisk, Solna, Sweden) was observed to produce MIC results very similar to those of the reference agar dilution test (GC agar base), with 100% of the results within 1 log2 dilution step of the reference MICs. The disk diffusion test zone diameters for all three drugs correlated at an acceptable level (r = -0.81 to -0.92) with the reference agar dilution MICs. Interpretive criteria for susceptibility were proposed for azithromycin at a MIC of < or = 2 micrograms/ml and a disk diffusion test zone of > or = 25 mm. No category for resistance was proposed because of the paucity of strains for which MICs were > 2 micrograms/ml. These tentative criteria should be further validated by correlations with clinical trial data for gonococcal strains (as they emerge) that have azithromycin MICs above the proposed susceptible category range.

Antimicrobial activity and spectrum of sparfloxacin tested against erythromycin-resistant Streptococcus pneumoniae isolates.

Recognition of a worldwide increase of penicillin-resistant Streptococcus pneumoniae and cross-resistance to other classes of antimicrobials have placed a great urgency on the need for new antimicrobial agents. Sparfloxacin, a novel pyridone carboxylic acid fluoroquinolone derivative was evaluated and compared to six other compounds for antimicrobial activity against erythromycin-resistant pneumococci (50 strains). The Etest susceptibility testing method was used to inoculate Mueller-Hinton agar supplemented with 5% sheep blood. There was extensive cross-resistance between erythromycin, clarithromycin (94%), and azithromycin (100%), but no cross-resistance was detected between macrolides/azalides and sparfloxacin (all strains susceptible at < or = 1.0 mu g/ml). Sparfloxacin (MIC90, 1 mu g/ml) was four-fold more active than ciprofloxacin and ofloxacin (MIC90, 4 mu g/ml). Sparfloxacin appears to possess excellent in vitro activity against erythromycin-resistant S. pneumoniae that were often highly resistant to beta-lactams, and further studies are recommended to investigate its in vivo efficacy against these multi-resistant organisms.