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PubMed1993

Identification of Pasteurella haemolytica A1 isolates from market-stressed feeder calves by use of enzyme and antimicrobial susceptibility profiles.

An epidemiologic study of Pasteurella haemolytica serovar 1 (Ph1) in market-stressed feeder calves from 7 farms in eastern Tennessee was conducted. The nasal mucus of each calf was cultured sequentially at the farm of origin (day 0), at an auction market (day 133), and at a feedyard in Texas (days 141, 148, 155, and 169). Of the 103 calves tested, 77 were culture-positive, including 1 on day 0, 1 on day 133, 20 on day 141, 57 on day 148, 50 on day 155, and 14 on day 169. From the 143 Ph1 isolates, 20 enzyme profiles were determined by use of a commercial enzyme system that detects 19 enzymatic reactions; 4 antimicrobial susceptibility profiles were obtained, using the disk-diffusion method, which evaluated susceptibility to 11 antibacterial drugs. All isolates were positive for acid phosphatase and alkaline phosphatase, but were negative for alpha-galactosidase, alpha-mannosidase, beta-glucosidase, beta-glucuronidase, cystine aminopeptidase, N-acetyl-beta-glucosaminidase, and trypsin. Other positive enzyme reactions included: leucine aminopeptidase, 140 Ph1 isolates; phosphohydrolase, 90 isolates; alpha-fucosidase, 63 isolates; esterase (C4), 59 isolates; valine aminopeptidase, 30 isolates; esterase lipase (C8), 24 isolates; beta-galactosidase, 2 isolates; and alpha-glucosidase, chymotrypsin and lipase (C14), 1 isolate each. Thirty-four Ph1 profiles were identified, using combined enzyme and antimicrobial susceptibility profiles. The data indicate that the strains isolated during the feedyard period may have been determined more by farm of origin (P < or = 0.001) than by habitation with calves from other farms while in the feedyard.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Proposed quality control guidelines for antimicrobial susceptibility tests using tilmicosin.

Quality control guidelines for tilmicosin, a novel veterinary-use-only macrolide, were developed in a multi-laboratory study according to established National Committee for Clinical Laboratory Standards (NCCLS) procedures (M23-T2). Tilmicosin was incorporated into Sensititre plates for broth microdilution endpoint testing and into two lots of 15-micrograms disks for Kirby-Bauer agar disk diffusion testing. One common lot and five unique lots of Mueller-Hinton media were used. (Broth was cation adjusted, and agar was supplemented with 5% defibrinated sheep blood.) Bacteria used for reference strains included Pasteurella haemolytica 128K, Pasteurella multocida ATCC 43137, and Staphylococcus aureus ATCC 29213 (microdilution) and ATCC 25923 (disk). Replicate tests were conducted. Disk diffusion and broth microdilution quality control ranges are proposed.

Animals↗
PubMed2003

Antimicrobial effect of 2% sodium hypochlorite and 2% chlorhexidine tested by different methods.

The objective of this study was to analyze the antimicrobial effect of 2% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) by agar diffusion test and by direct exposure test. Five microorganisms: Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aernginosa, Bacillus subtilis, Candida albicans, and one mixture of these were used. These strains were inoculated in brain heart infusion (BHI) and incubated at 37 degrees C for 24 h. For the agar diffusion test (ADT), 18 Petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the microbial suspensions, using sterile swabs that were spread on the medium, obtaining growth injunction. Fifty-four paper disks (9 mm in diameter) were immersed in the experimental solutions for 1 min. Subsequently, three papers disks containing one of the substances were placed on the BHI agar surface in each agar plate. The plates were maintained for 1 h at room temperature, and then incubated at 37 degrees C for 48 h. The diameter of microbial inhibition was measured around the papers disks containing the substances. For the direct exposure test, 162#50 sterile absorbent paper points were immersed in the experimental suspensions for 5 min, and were then placed on Petri plates and covered with one of the irrigant solutions, or with sterile distilled water (control group). After intervals of 5, 1 0 and 30 min, the paper points were removed from contact with the solutions and individually immersed in 7 ml of Letheen Broth, followed by incubation at 37 degrees C for 48 h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1 ml inoculum obtained from the Letheen Broth was transferred to 7 ml of BHI, and incubated at 37 degrees C for 48 h. Bacterial growth was again evaluated by turbidity of the culture medium. Gram stain of BHI cultures was used for verification of contamination and growth was determined by macroscopic and microscopic examination. The best performance of antimicrobial effectiveness of NaOCI was observed in the direct exposure test, and of CHX was observed in the agar diffusion test. The magnitude of antimicrobial effect was influenced by the experimental methods, biological indicators and exposure time.

Agar↗
PubMed2006

The release of bovine serum albumin from polyurethane based hydrophilic and hydrophobic disks and microbiological interactions.

Polyurethane (PU) based hydrophobic and hydrophilic disks were prepared by graft copolymerization of PU with vinyl monomers, acryl amid (AAm), itaconic acid (IA), acrylic acid (AA) and crotonic acid (CA). Grafting reactions were performed in PU-dioxane solution using benzoyl peroxide as initiator. Air-water and cyclohexan-water contact angle values of the disks (thetaair and thetacy) were measured via "Captive Bubble Method". Surface free energy values of the disks were determined by using thetaair and thetacy via "Two Liquid Method" and those were compared with the swelling percentage values of the disks. The release of Bovine Serum Albumin (BSA) from protein added hydrophilic and hydrophobic PU disks were defined by spectrophotometric measurements at lambda=278 nm in phosphate buffer saline (PBS). BSA releasing is completed around 48 h for all disks. The disks were also characterized by FTIR spectra and SEM micrographs. In vitro attachment of Candida albicans (C. albicans) and Lactobacillus plantarum (L. plantarum) on PU based hydrophilic and hydrophobic disks was studied at 37 degrees C. While C. albicans attached on to all disks, L. plantarum only selectively attached. The attachment percentage values of C. albicans (25%) and L. plantarum (20%) on hydrophobic PU disk were higher than hydrophilic PU disks. The antimicrobial activity of disks was also tested against C. albicans and L. plantarum. IA and AAm grafted PU disks showed inhibitory effect for the both test bacteria.

Absorption↗
PubMed1980

[Automated direct antimicrobial susceptibility testing of urine specimens].

Two microscopical screening methods have been used to assay the suitability of urine samples for automated direct antimicrobial susceptibility testing by the means of a "MS-2 Microbiology System" apparatus. Gram stained smears showed if specimens were monomicrobic and fresh-mount bacterioscopy gave information about presumptive counts to establish inoculum size. The results obtained by the automated method have been compared with those of the direct disk diffusion method and the classical Stokes method on a single isolated colony. The three systems were reliable and only 7% of specimens gave major discrepancies and 15% minor errors. The influence of each antibiotic drug and of each bacterial species on the discrepancies has been discussed. Direct susceptibility testing by MS-2 seems to be accurate and in the same time so fast (5-6 h vs. 18-24 h) to appear very useful in the rational guide of chemotherapy in the more severe UTI.

Anti-Bacterial Agents↗
PubMed1997

Antimicrobial susceptibility testing in Sweden. II. Species-related zone diameter breakpoints to avoid interpretive errors and guard against unrecognized evolution of resistance.

The Swedish Reference Group for Antibiotics appointed a subcommittee on methodology (SRGA-M) in 1987 to investigate ways of defining interpretive breakpoints for antimicrobial susceptibility testing. The minimum inhibitory concentration (MIC) breakpoints for susceptibility categories are mainly based on pharmacological properties of the antibiotic, and they are, with few exceptions, valid for all species. However, for several species the MIC breakpoints have failed to distinguish strains with reduced susceptibility from normal susceptible strains. Disk diffusion is the routine method for susceptibility testing in Sweden. Studies of distribution of MICs and zone diameters for clinically important bacterial species have resulted in an emphasis on resistance rather than on susceptibility. The SRGA-M chose to place the zone diameter breakpoints close to the native (often susceptible) population of each species or group of related species. Such species-related zone diameter breakpoints used for susceptibility categories no longer correspond to the pharmacological MIC breakpoints, but divide each species into the fully susceptible (native) population and into those isolates/populations that have acquired a resistance mechanism, resulting in high- or low-grade resistance. By this method the risk of reports of false susceptibility is minimized and early detection of the emergence of antibiotic resistance is ensured.

Anti-Bacterial Agents↗
PubMed1982

Rapid method for determining antimicrobial susceptibility of Haemophilus influenzae.

A method was developed to determine the susceptibility of Haemophilus influenzae to ampicillin, cefamandole, and chloramphenicol by using the MS-2 system (Abbott Laboratories) for determining minimum inhibitory concentrations (MIC). The MS-2 results for 132 strains of H. influenzae were compared with the results of agar disk diffusion, agar dilution, and beta-lactamase tests. Twenty-four strains (18.2%) of H. influenzae were resistant to ampicillin by the agar dilution method, as opposed to 25 strains by the MS-2 method. For a beta-lactamase-negative strain, the agar dilution MIC was 4 micrograms/ml, and the MS-2 MIC was 16 micrograms/ml. Twenty-one strains produced beta-lactamase; two beta-lactamase-negative strains were resistant by MS-2, agar dilution, and agar disk diffusion. In addition, one beta-lactamase-negative strain, for which the agar dilution MIC was 32 micrograms/ml and the MS-2 MIC was 16 micrograms/ml, was sensitive by agar disk diffusion. Overall, the MS-2 method compared favorably with the agar dilution method for determining the MIC of ampicillin, cefamandole, and chloramphenicol for H. influenzae.

Ampicillin↗
PubMed1998

Evaluation of the E test for antimicrobial susceptibility testing of Pseudomonas aeruginosa isolates from patients with long-term bladder catheterization.

The E test was evaluated in comparison with reference agar methods (National Committee for Clinical Laboratory Standards) for the susceptibility testing of 248 Pseudomonas aeruginosa isolates from bladder-catheterized patients against nine antibiotics. The E-test MICs correlated well with those determined by the agar dilution and disk diffusion reference methods (88 and 92.5% within 1 log2 dilution step, respectively), confirming that the E test is a reliable method for the determination of MICs of antibiotics for catheterization-associated P. aeruginosa isolates.

Anti-Bacterial Agents↗
PubMed2005

Antimicrobial resistance in food and clinical Aeromonas isolates.

This study highlights the incidence of resistance and the presence of plasmids in human and food isolates of Aeromonas in Brazil. A total of 83 Aeromonas spp. strains (28 isolated from human and 55 from fresh lettuce) were studied. Thirty-five were identified as A. hydrophila complex and 48 as A. caviae complex. All strains were shown to be susceptible to imipenem, amikacin, gentamicin, tobramycin and ciprofloxacin by the disk diffusion method. Resistance to antimicrobial agents was observed in strains of both food and clinical origin. The food strains were resistant to ampicillin/sulbactam, cefoxitin and tetracycline, while the clinical strains presented resistance to ampicillin/sulbactam, cefotaxime, ceftazidime, cefoxitin, sulfamethoxazole/trimethoprim, chloramphenicol and tetracycline. The minimal inhibitory concentrations of chloramphenicol, tetracycline and sulfamethoxazole/trimethoprim were tested by agar dilution. Thirteen strains isolated from vegetables were resistant to tetracycline (MIC 16 microg ml-1). Two A. hydrophila strains and one A. caviae strain presented extracromosomal DNA (3 and 15 kb plasmids, respectively). The tetracycline resistance phenotype determinant was related to the 15 kb plasmid according to cure and transformation experiments.

Aeromonas↗
PubMed1980

Antimicrobial susceptibility of Campylobacter jejuni and Campylobacter fetus subsp. fetus to eight cephalosporins with special reference to species differentiation.

Agar dilution antimicrobial susceptibility testing showed that Campylobacter jejuni was significantly more resistant than Campylobacter fetus subsp. fetus (intestinalis) to cephalosporin C, cephaloridine, cephalothin, cefazolin, and cefamandole. No species differences in susceptibility were noted with cephalexin, cefotaxime, and cefoxitin. Rapid species differentiation on the basis of an antibiogram could be achieved with the disk diffusion method. C jejuni failed to produce a zone of inhibition around a 30-microgram cephalothin disk but produced a significant zone around a 30-microgram nalidixic acid disk. C. fetus subsp. fetus (intestinalis) produced exactly the reverse pattern.

Campylobacter↗
PubMedDate not supplied

In vitro susceptibility of Stenotrophomonas maltophilia to various antimicrobial combinations.

Stenotrophomonas maltophilia has emerged as a significant pathogen in compromised patients, causing infections which are difficult to treat. Clinical isolates from patients in the Tucson area were tested against single and combination antibiotics using three testing methods. Ticarcillin/clavulanate, trimethoprim/sulfamethoxazole and trovafloxacin provided comparable inhibitory activity, in vitro. Ciprofloxacin, imipenem and ticarcillin were active less often. Agreements between disk diffusion and broth microdilution results were poor for ciprofloxacin and trimethoprim/sulfamethoxazole; however, agreement was > or = 90% for the other drugs tested. Major or very major errors were observed with ticarcillin, ticarcillin/clavulanate, and trovafloxacin. The addition of aztreonam to ticarcillin/clavulanate enhanced the activity compared to ticarcillin/clavulanate alone using the double-disk diffusion, broth microdilution (checkerboard), and time-kill testing methods. Trovafloxacin exhibited good activity by all three methods, with bactericidal activity at > or = 2x MIC. These results indicate that the newer fluoroquinolones or the triple combination of ticarcillin/clavulanate plus aztreonam may be potential options for treatment of infection caused by S. maltophilia in patients who are intolerant to or fail trimethoprim/sulfamethoxazole therapy.

Anti-Infective Agents↗
PubMed1999

Susceptibility of Streptococcus pneumoniae isolated from the respiratory tract of hospitalized children with respiratory tract infections.

The most frequent nasopharyngeal carriers of Streptococcus pneumoniae are young children. Frequent use of antimicrobial therapy in children facilitates the selection of penicillin-resistant strains in this population. These strains, especially if highly resistant, may cause serious therapeutic problems. Aim of the study was to monitor penicillin- and multidrug-resistant S. pneumoniae strains in hospitalized children with respiratory tract infections. Hospitalized children up to five years were examined for S. pneumoniae presence in their upper respiratory tract. Susceptibility to penicillin, erythromycin, trimethoprim/sulfamethoxazole, tetracycline, and chloramphenicol was determined by the disk-diffusion method. The minimal inhibitory concentrations (MIC) of penicillin, erythromycin and trimethoprim/sulfamethoxazole were measured by the E-test. S. pneumoniae strain was isolated from 60 (34.7%) out of 173 microbiologically examined children; 2 different strains were isolated in 9 cases. Nine strains (13.0%) were penicillin resistant with MICs ranging from 1.5 to 8 mg/L, and 17 strains (24.6%) had intermediate susceptibility. Seventeen (24.6%) strains were erythromycin resistant (MIC > or = 1 mg/L). Eighteen strains (26.1%) were resistant and 7 strains (10.1%) were intermediately susceptible to trimethoprim/sulfamethoxazole. Ten strains (14.5%) were not susceptible to tetracycline, and 11 (15.9%) to chloramphenicol. Non-susceptibility (resistance or intermediate susceptibility) to the tested antimicrobials was more prevalent in penicillin-nonsusceptible strains. The current level of S. pneumoniae resistant to antimicrobial drugs in children with respiratory tract infections in the hospital department monitored in our study do not cause problems in the choice of antibacterial therapy. Penicillins still can remain the drug of choice in cases when typical bacterial causing agents of respiratory tract infections are suspected. (Tab. 3, Fig. 2, Ref. 31.)

Child, Preschool↗
PubMedDate not supplied

Susceptibility of Moraxella catarrhalis to 21 antimicrobial drugs: validity of current NCCLS criteria for the interpretation of agar disk diffusion antibiograms.

Ninety-four clinical isolates of Moraxella catarrhalis were examined for susceptibility to 21 antimicrobial drugs; 67 isolates (= 71.3%) produced beta-lactamase(s). In terms of antibiotic resistance, the number of isolates resistant to penicillin G, ampicillin, and cotrimoxazole were 56, 32, and 1, respectively. The number of isolates with intermediate susceptibility to penicillin G, ampicillin, ciprofloxacin, ofloxacin, cotrimoxazole, and fosfomycin were 11, 34, 1, 2, 2, and 47, respectively. All 94 isolates proved susceptible to ampicillin + 10 micrograms/ml of sulbactam, amoxicillin + 4 micrograms/ml of clavulanic acid, cefuroxime, cefotaxime, cefepime, cefepime, cefixime, imipenem, meropenem, chloramphenicol, doxycycline, tetracycline, fusidic acid, erythromycin, clarithromycin, and rifampin, as based on currently valid NCCLS criteria, where applicable. There were no very major or major discrepancies between agar dilution and agar disk diffusion test results. There were only a few minor discrepancies between test results, specifically: penicillin G (category IV = 4, category VI = 1); ampicillin (category IV = 4, category V = 1, category VI = 7), amoxicillin + clavulanic acid (category III = 11), cotrimoxazole (category IV = 1, category V = 1, category VI = 1), ciprofloxacin (category V = 1), and ofloxacin (category VI = 2). The sole exception was fosfomycin, with a total of 25 minor discrepancies encountered (category III = 14, category V = 9, category VI = 2). Wilkins-Chalgren agar compared favorably with Mueller-Hinton agar following examination with 11 selected antimicrobial drugs against 31 representative isolates of M. catarrhalis.

Anti-Bacterial Agents↗
PubMed2002

Multicentre assessment of linezolid antimicrobial activity and spectrum in Europe: report from the Zyvox antimicrobial potency study (ZAPS-Europe).

OBJECTIVE: To evaluate the in vitro spectrum and activity of linezolid, a recent oxazolidinone, according to well-controlled surveillance data from 42 medical centers in 13 countries throughout Europe. METHODS: Participants tested the susceptibility of 125 clinical strains of enterococcal and staphylococcal species against 13 drugs using reference broth microdilution trays or the standardized disk diffusion method of the National Committee for Clinical Laboratory Standards (NCCLS). Streptococcal species (n = 25 at each center) were tested against six drugs using E test (AB BIODISK, Solna, Sweden). Quality assurance testing was conducted using NCCLS-recommended strains and verification of resistance to linezolid and other selected agents was performed by retesting strains at the regional (Europe) and international (USA) monitor sites. RESULTS: A total of 5598 strains from throughout Europe (91% compliance) were tested. Vancomycin resistance was reported in only 0.6 and 3.0% of Enterococcus faecalis and E. faecium, respectively. Penicillin resistance occurred in 25.1% of Streptococcus pneumoniae; 4.9% at the high-level (> or =2 mg/L). The MIC90 for linezolid was 1 mg/L for streptococci and 2 mg/L for enterococci and staphylococci. Using the US FDA- and EUCAST-recommended susceptible breakpoints for linezolid, there were no confirmed reports of linezolid resistance [minimum inhibitory concentration (MIC), > or =8 mg/L]. The distribution of linezolid MIC values was unimodal and varied between 0.25 and 1 mg/L for streptococci (>90% of isolates), and between 1 and 2 mg/L for staphylococci (>90%) and enterococci (>95%). There were no differences in linezolid susceptibility in the vancomycin-, oxacillin-, or penicillin-resistant subsets of strains when compared to susceptible organism populations. CONCLUSIONS: Compared to the North American component of this study, there was substantially less vancomycin resistance among E. faecium isolates (Europe 3.0% vs. North America 63.4%). While the occurrence of penicillin-resistant S. pneumoniae in Europe and North America was similar (25.1% vs. 29.7%), the recovery of high-level penicillin-resistant strains was nearly three-fold higher in North America (4.9% vs. 13.2%). Only linezolid was universally active against all the tested Gram-positive isolates at </=4 mg/L.

Acetamides↗
PubMed1993

[A nationwide survey of antimicrobial susceptibilities of clinical isolates to antibiotics in Japan (1988-1990)].

This study was conducted to investigate susceptibilities of clinical isolates to antibacterial agents at 149 hospitals throughout Japan from September to December in both 1989 and 1990. In this study, identifications and susceptibility testings were carried out at each hospital laboratory. The susceptibility testings were performed according to the disk diffusion method recommended by NCCLS. Staphylococcus aureus and coagulase-negative staphylococci showed high or moderate resistance rates to beta-lactam antibiotics, but Streptococcus pyogenes and Streptococcus pneumoniae were highly susceptible to them. Enterococcus faecalis was susceptible to imipenem (IPM) and piperacillin but resistant to beta-lactam antibiotics and aminoglycosides. Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were susceptible to beta-lactam drugs and aminoglycosides. Enterobacter cloacae, Serratia marcescens, Proteus vulgaris, Morganella morganii and Pseudomonas aeruginosa had a good susceptibility to IPM and aminoglycosides. Bacteroides fragilis was highly susceptible to IPM. IPM had strong antibacterial activity to many species of clinical isolates, including strains which were resistant to commonly used antibiotics.

Aminoglycosides↗
PubMed1997

[Usefulness of the disk diffusion method for evaluating the sensitivity of Neisseria meningitidis to penicillin and cefotaxime].

BACKGROUND: Routine susceptibility testing of Neisseria meningitidis to penicillin and other beta lactams is recommended after the isolation of N. meningitidis of moderately resistant to penicillin (MRP). We have evaluated the disk-diffusion method to determine susceptibility of N. meningitidis to penicillin (using disks of either penicillin or oxacillin) and to cefotaxime. METHODS: Fifty-four strains of N. meningitidis isolated from clinical samples were studied. MICs of penicillin and cefotaxime were determined by microdilution. Disks of 2 U of penicillin, 1 microgram of oxacillin and 30 micrograms of cefotaxime and two culture media, Mueller-Hinton agar (MHA) and MHA supplemented with 5% sheep blood (MHS) were used in the disk-diffusion assay. RESULTS: For disk of 2 U of penicillin assayed in MHA, 86.4% of the susceptible strains and 20% of MRP strains were considered susceptible when a breakpoint of 28 mm was considered. None of the MRP strains was considered susceptible when using MHS, but only 38.6% of susceptible strains appeared as such on this medium. When a 1 microgram oxacillin disk was used all MRP strains presented an inhibition zone < or = 10 mm on both MHA and MHS, but 54.4 and 4.5% of susceptible strains presented an inhibition zone > or = 11 mm on MHA and MHS, respectively. All strains were susceptible to cefotaxime, showing inhibition zones around a 30 micrograms disk on MHA and MHS of > or = 35 mm and > or = 25 mm, respectively. CONCLUSION: Disk diffusion with cefotaxime (30 micrograms) allows to determine susceptibility of N. meningitidis to this antimicrobial agent. Discs of penicillin (2 U) and oxacillin (1 microgram) are not useful for screening of MRP N. meningitidis.

Cefotaxime↗
PubMed1999

Use of an oxacillin disk screening test for detection of penicillin- and ceftriaxone-resistant pneumococci.

In a context of worldwide emergence of resistance among Streptococcus pneumoniae strains, early detection of strains with decreased susceptibility to beta-lactam antibiotics is important for clinicians. If the 1-microgram oxacillin disk diffusion test is used as described by the National Committee for Clinical Laboratory Standards, no interpretation is available for strains showing zone sizes of </=19 mm, and there is presently no disk diffusion test available for screening cephalosporin resistance. The zones obtained by the diffusion method by using the 1-microgram oxacillin disk were compared with penicillin MICs for 1,116 clinical strains and with ceftriaxone MICs for 695 of these strains. Among the 342 strains with growth up to the 1-microgram oxacillin disk margin, none were susceptible (MIC, </=0.06 microgram/ml), 62 had intermediate resistance (MIC, 0.12 to 1.0 microgram/ml), and 280 were resistant (MIC, >/=2.0 microgram/ml) to penicillin. For ceftriaxone, among 98 strains with no zone of inhibition in response to oxacillin, 68 had intermediate resistance (MIC, 1.0 microgram/ml), and 22 were resistant (MIC, >/=2.0 microgram/ml). To optimize the use of the disk diffusion method, we propose that the absence of a zone of inhibition around the 1-microgram oxacillin disk be regarded as an indicator of nonsusceptibility to penicillin and ceftriaxone and recommend that such strains be reported as nonsusceptible to these antimicrobial agents, pending the results of a MIC quantitation method.

Ceftriaxone↗
PubMed2002

Prevalence of antimicrobial resistance in Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and Streptococcus pyogenes: results of a multicentre study in Turkey.

The in vitro activities of several antimicrobial agents against clinical isolates of Streptococcus pneumoniae (283), Haemophilus influenzae (272), Moraxella catarrhalis (179) and Streptococcus pyogenes (256) were determined in a multicentre study with the participation of five hospitals from four cities in Turkey. Penicillin resistance in S. pneumoniae was evaluated using the E-test and the remaining agents by disk diffusion. For S. pneumoniae overall 25.8% of the isolates were intermediately and 3.9% were highly resistant to penicillin and resistance to chloramphenicol, azithromycin and trimethoprim/sulphamethoxazole (TMP/SMX) was 3.8, 2.1 and 55.4%, respectively. Seven percent of H. influenzae produced beta-lactamase and all were susceptible to cefotaxime and azithromycin; the highest rate of resistance, 23.5%, was for TMP/SMX. Eighty-one percent of M. catarrhalis isolates produced beta-lactamase, 18.4% were resistant to TMP/SMX and all were susceptible to sulbactam/ampicillin combination. Resistance to chloramphenicol and azithromycin of S. pyogenes was 2.2 and 1.9%, respectively.

Anti-Bacterial Agents↗