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PubMed2006

Update on antimicrobial susceptibilities of bacterial isolates from canine and feline otitis externa.

The in vitro susceptibility of a total of 1819 bacterial isolates from canine and 103 isolates from feline otitis externa cases to 13 antimicrobial drugs over a 5-year period was evaluated. Among topically used drugs, 90% of isolates were susceptible to gentamicin. Susceptibility of Pseudomonas aeruginosa to gentamicin was 85%, and to polymyxin B 100%. For isolates other than the Pseudomonas sp., susceptibility was highest to amoxicillin-clavulanic acid.

Animals↗

PubMed1997

Influence of intraocular lens haptic material on bacterial isolates from anterior chamber aspirate.

PURPOSE: To determine whether intraocular lens (IOL) type affects the bacterial count in anterior chamber aspirates obtained immediately after cataract surgery. SETTING: L.V. Prasad Eye Institute, Hyderabad, India. METHODS: This in vivo study evaluated two groups of eyes that had uneventful cataract extraction and implantation of one of two types of IOLs: all poly(methyl methacrylate) (PMMA) (n = 73) or polypropylene haptic (n = 83). Anterior chamber fluid aspirates (0.1 mL) were obtained with a 30 gauge cannula at the end of surgery and inoculated onto chocolate agar and in thioglycolate broth. Microbiology evaluation was performed using standard methods. RESULTS: Seven eyes (9.5%) with all-PMMA IOLs and 21 (25.3%) with polypropylene haptic IOLs were positive for bacterial isolates (P = .0322; chi-square test). Mean colony count (+/-SD) was 11.43 +/- 3.78 and 13.16 +/- 4.78 colony-forming units/ milliliter in the PMMA and polypropylene haptic IOL groups, respectively. No eye developed endophthalmitis. CONCLUSION: Polypropylene haptic IOLs were associated with a significant increase in bacteria in the anterior chamber.

Aged↗

PubMedDate not supplied

Ticarcillin: a collaborative in vitro comparison with carbenicillin against over 9,000 clinical bacterial isolates.

The minimal inhibitory concentrations of ticarcillin and carbenicillin were determined for 9,236 clinical bacterial isolates by the broth microdilution method at four participating laboratories. Ticarcillin showed significantly increased activity against Klebsiella pneumoniae (P less than .001), Pseudomonas aeruginosa (P less than .001) and Aeromonas hydrophilia (P less than .005) when compared to carbenicillin, but no signifcant differences were observed against other gram-negative organisms. Ticarcillin was consistently less active against the gram-positive cocci, and these differences were significant for Staphylococcus aureus (P less than .001), Streptococcus agalactiae (P less than .001), Staphylococcus epidermidis (P less than .001) and Streptococcus viridans (P less than .005). Significant regional and institutional differences in susceptibility to the two drugs were observed for several species, including common nosocomial pathogens such as S. aureus, P. aeruginosa, K. pneumoniae and Escherichia coli.

Bacillus↗

PubMed1989

In vitro activity of AT-4140 against clinical bacterial isolates.

The activity of AT-4140, a new fluoroquinolone, was evaluated against a wide range of clinical bacterial isolates and compared with those of existing analogs. AT-4140 had a broad spectrum and a potent activity against gram-positive and -negative bacteria, including Legionella spp. and Bacteroides fragilis. The activity of AT-4140 against gram-positive and -negative cocci, including Acinetobacter calcoaceticus, was higher than those of ciprofloxacin, ofloxacin, and norfloxacin. Its activity against gram-negative rods was generally comparable to that of ciprofloxacin. Some isolates of methicillin-resistant Staphylococcus aureus (MIC of methicillin, greater than or equal to 12.5 micrograms/ml) were resistant to existing quinolones, but many of them were still susceptible to AT-4140 at concentrations below 0.39 micrograms/ml. The MICs of AT-4140, ciprofloxacin, ofloxacin, and norfloxacin for 90% of clinical isolates of methicillin-resistant S. aureus were 0.2, 12.5, 6.25, and 100 micrograms/ml, respectively. AT-4140 was bactericidal for each of 20 clinical isolates of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, and Pseudomonas aeruginosa at concentrations near the MICs. AT-4140 inhibited the supercoiling activity of DNA gyrase from E. coli.

4-Quinolones↗

PubMed1969

Sensitivity of freshly isolated bacterial pathogens to certain antibiotics and nitrofurazone.

The results of antibiotic tests on bacterial pathogens freshly isolated from avian tissues and bovine milk are presented. Coliform isolates from the avian species showed an increased resistance to antibiotics while those which produced bovine mastitis had remained generally more sensitive. The staphyloccoci and streptococci isolated from bovine milk showed an increase in resistance to most of the antibiotics tested. The indiscriminate administration of antibiotics to livestock and poultry has no doubt encouraged the development of resistant forms of bacteria and has made treatment with such products less effective.

Animals↗

PubMed2002

Fluorescent amplified fragment length polymorphism probabilistic database for identification of bacterial isolates from urinary tract infections.

The ability of the fluorescent amplified fragment length polymorphism (FAFLP) technique to identify bacterial isolates from urinary tract infections (UTIs) was investigated. FAFLP was carried out using the single primer combination MseI plus CT and EcoRI plus 0, and information-rich FAFLP profiles were generated from all 69 UTI isolates studied, which comprised both gram-negative and gram-positive bacteria encompassing eight genera. The genetic relatedness of these 69 bacteria was determined by cluster analysis, and this revealed eight main groups corresponding to the eight bacterial genera. Finer discrimination on the same dendrogram showed species and subspecies differentiations, thus demonstrating the potential of FAFLP for describing a wide diversity range within microbial populations. The interpretation of FAFLP profiles is often complicated because it relies upon the investigator interpreting dendrograms; this process may be subjective if the tree is complicated, particularly if it includes polytomies (unresolved nodes). Therefore, we have developed a method based on Bayes' theorem for the identification of bacteria against an FAFLP probabilistic identification matrix. Thus, FAFLP is suitable for the objective identification of causal agents of UTI, and the procedure offers great potential in the clinical laboratory.

Bacterial Infections↗

PubMed2000

Trends of antimicrobial resistance in bacterial isolates from a small animal referral hospital.

A longitudinal, retrospective investigation was made of antimicrobial resistance in bacterial isolates obtained from clinical cases in a small animal hospital between 1989 and 1997. Isolates of Escherichia coli and Staphylococcus species were used as Gram-negative and Gram-positive indicator organisms, respectively, and the annual prevalence of antimicrobial resistance was calculated for each organism to each of nine (for E coli) and 11 (for Staphylococcus species) appropriate antimicrobials, including enrofloxacin. Using a chi-square test for trend, statistically significant, rising trends were identified in the resistance of E coli to amoxycillin (P=0.04), clavulanate-amoxycillin (P<0.01) and streptomycin (P<0.01), and in the resistance of Staphylococcus species to erythromycin (P<0.01). There was an equivocal, rising trend for the resistance of Staphylococcus species to cephalexin. No significant trends were apparent for any of the other 15 organism/drug interactions. The annual prevalence of multiple drug resistance was calculated for E coli, Proteus species, Pseudomonas species, staphylococci and streptococci, but no statistically significant trends were identified.

Animals↗

PubMed1991

In vitro activity of cefpodoxime against bacterial isolates obtained from patients with cancer.

The in vitro activity of cefpodoxime, an oral cephalosporin ester, against 792 bacterial isolates representing 36 species was evaluated in comparison to that of ciprofloxacin and trimethoprim/sulfamethoxazole (TMP/SMX). Cefpodoxime inhibited the majority of Streptococcus spp., Haemophilus influenzae and Proteus mirabilis at a concentration of less than or equal to 0.12 microgram/ml. It was also active against Citrobacter diversus, Escherichia coli, Klebsiella spp., Proteus vulgaris, Serratia marcescens and methicillin-susceptible Staphylococcus aureus isolates. Overall, cefpodoxime appeared to be less active than ciprofloxacin and TMP/SMX against many pathogens common in cancer patients.

Bacteria↗

PubMed1988

Comparative in vitro activity of the new difluoro-quinolone temafloxacin (A-62254) against bacterial isolates from cancer patients.

The in vitro activity of temafloxacin, a new difluoro quinolone agent, against 725 bacterial isolates representing 32 species was evaluated in comparison with that of ciprofloxacin. Temafloxacin inhibited the majority of Enterobacteriaceae isolates at a concentration of less than or equal to 0.5 microgram/ml. It was also extremely active against Acinetobacter spp. and Aeromonas hydrophila. Its activity was 2-8 fold less than that of ciprofloxacin against most gram-negative isolates. Methicillin-susceptible and methicillin-resistant Staphylococcus aureus, coagulase-negative Staphylococcus spp., Streptococcus spp., Listeria monocytogenes, Bacillus spp. and group JK corynebacteria were inhibited at concentrations equal to that of ciprofloxacin.

Anti-Infective Agents↗

PubMed1994

Antimicrobial susceptibility patterns of bacterial isolates at the American University Medical Center in Lebanon.

In Lebanon, knowledge of the prevailing pattern of bacterial resistance to antimicrobial agents has been limited, particularly because of 15 years of civil strife. Thus, the current study was conducted to determine the antimicrobial susceptibility patterns of nonselected bacterial isolates recovered from recent clinical specimens, using the standardized disk agar diffusion technique. A total of 5216 isolates (1443 Gram positive and 3773 Gram negative) were examined. Over 92% of Staphylococcus aureus and coagulase-negative staphylococci (CNS) were resistant to penicillins. Methicillin resistance was more frequently noted among CNS (28%) compared with S. aureus (18%). For the pneumococci, 27% of the isolates were resistant to penicillin G. High but variable rates of multidrug resistance were encountered among Acinetobacter spp., Pseudomonas spp., Serratia spp., Citrobacter spp., and Enterobacter spp. Ampicillin resistance was detected in 65% of Escherichia coli and in 20% of Haemophilus influenzae isolates. Although one resistant Salmonella typhi strain was observed, 17% of other Salmonella spp. and 60% of Shigella spp. proved to be resistant to ampicillin, chloramphenicol, and cotrimoxazole. Among Vibrio cholerae isolates, high resistance to tetracycline (71%) and trimethoprim-sulfamethoxazole (94%) was observed. The overall antimicrobial resistance rates in Lebanon seem to fall between figures reported from the Arabian Gulf countries (higher) and those from medical centers in the United States (lower).

Drug Resistance, Microbial↗

PubMedDate not supplied

Inhibitory effect of different enterocins against fecal bacterial isolates.

Anti-microbial activity of five different enterocins produced by ruminal and environmental enterococci against fecal bacterial isolates was tested. The majority of all 61 strains (80.4%) were inhibited by all enterocins used. The remaining strains were inhibited at least by one enterocin. The highest activity, 51,200 arbitrary units per ml-1 (AU ml-1) was measured when crude extracts of enterocin V24 (CE V24) were used against enterococci. CE AL41 and EK13 showed an activity of 25,600 AU ml-1. The lowest activity was obtained with Enterocin CE EC24 (100-400 AU ml-1). Crude extract of enterocin CCM4231 inhibited the indicator strains with an activity ranging from 100 up to 6400 AU ml-1, which is in accordance with our previous results. It further indicates the probable use of enterocins or its producers in environmental biotechnology with the aim to increase the effectiveness of sanitation of animal excrements after standard treatment.

Animals↗

PubMedDate not supplied

Ceftriaxone: in vitro activity against 410 bacterial isolates compared with cefotaxime.

The in vitro activity of the two new cephalosporins, cefotaxime and ceftriaxone, against 410 bacterial isolates was compared using an agar dilution method. Both compounds were highly active against Enterobacteriaceae, including indole-positive Proteus and Providencia; the great majority of the isolates were inhibited by 0.06 mg/l of either drug. Activity against Pseudomonas aeruginosa and Staphylococcus aureus was moderate, and enterococci were resistant. All Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae isolates were susceptible to 0.03 mg/l of either drug. The isolates belonging to the Bacteroides fragilis group were inhibited over a wide range of concentrations and some were highly resistant (MIC greater than or equal to 64 mg/l). There were no significant differences in the antibacterial activity of the two drugs against our isolates. Both drugs may be of potential use in the treatment of serious infections caused by Enterobacteriaceae; they may prove to be a useful alternative to the aminoglycosides.

Bacteria↗

PubMed1990

Susceptibility pattern of bacterial isolates to lomefloxacin.

The in vitro susceptibility pattern with respect to lomefloxacin was determined in case of 1009 bacterial isolates from clinical specimens with varying susceptibility to commonly used antimicrobial agents. The MIC50 and MIC90 values of lomefloxacin for the Gram negative bacilli showed susceptibility value ranging between 0.12 to 4.0 micrograms/ml, while 90 per cent of the streptococci tested were inhibited only at 16 micrograms/ml. Lomefloxacin was comparable in activity to enoxacin and ciprofloxacin but it was more active than norfloxacin and nalidixic acid.

Anti-Infective Agents↗

PubMed1989

The comparative in vitro activity of ofloxacin and selected ophthalmic antimicrobial agents against ocular bacterial isolates.

The in vitro activity of ofloxacin, a new fluoroquinolone anti-infective agent, was evaluated against 419 ocular bacterial isolates of 55 species to determine its potential as a topical agent for the treatment of ocular infections. Other agents tested in this study, in which a modified tube-dilution procedure was used, include norfloxacin, gentamicin, tobramycin, chloramphenicol, and polymyxin B. Ofloxacin demonstrated good to excellent activity against a variety of gram-positive and gram-negative pathogens. The minimum inhibitory concentration against 90% of all bacterial strains tested (MIC90) of ofloxacin was 0.5 microgram/ml for Staphylococcus aureus and S. epidermidis, 2 micrograms/ml for Streptococcus pneumoniae, and 4 micrograms/ml for Pseudomonas aeruginosa. These species were more susceptible to ofloxacin than to any of the nonquinolones tested. The MIC90 of ofloxacin was lower than that of norfloxacin, another quinolone, against S. aureus, S. epidermidis, and St. pneumoniae and equal to that of norfloxacin against P. aeruginosa. Because of its broad spectrum of activity and excellent in vitro activity, we concluded that ofloxacin has the potential for development into a superior topical treatment for ocular infection.

Anti-Bacterial Agents↗

PubMed1978

Antibiotic resistance factors and other plasmids in bacterial isolates from hospitalized patients.

Among 186 arbitrarily selected gram-negative as well as gram-positive bacterial strains isolated from hospitalized patients, 63% were found to harbour plasmids, 42% of the strains with extrachromosomal DNA showed more than one plasmid DNA band in the agarose gel electrophoresis. The highest plasmid frequency was found in the enteric gram-negative microorganisms: 95% to 76% of the analyzed Enterobacter species, Klebsiella pneumoniae and E. coli isolates harboured plasmids. The plasmid frequency in the Staphylococci and group D Streptococci ranged between 36% and 75%. The examined Pneumococci strains were sensitive to all antibiotics and were found to be free of plasmids. In 45% of the enteric strains studied, the resistance markers were found to be transferable to a sensitive E. coli recipient by conjugation. Some of the resistance genes had not formed a stable complex with a plasmid and were lost during in vitro passage of their bacterial host. The loss of R-factors in vitro causes false diagnostic findings in regard to the in vivo antibiotic sensitivity of such strains. With purified plasmid DNA, individually isolated from E. coli strains, transformants were obtained carrying ampicillin resistance specifying plasmids of different molecular size. This result indicates that plasmids of different molecular size in a single bacterial cell can simultaneously carry ampicillin resistance genes. All findings indicated that the plasmids play an important role for the transfer and the maintenance of antibiotic resistance specifying genes in the bacterial isolates from clinical patients. However, most of the functions coded for by the numerous plasmids in the bacterial isolates remained unknown.

Anti-Bacterial Agents↗

PubMed2005

Spectrum and antibiotic susceptibility pattern of bacterial isolates from conjunctival swabs.

Conjunctivitis is the most common disease of conjunctiva which occurs by exogenous or endogenous source. Bacterial conjunctivitis is the most common type of this infection for which emperical treatment is started without knowing the etiological agents because prior cultures are generally not taken. We conducted this survey to study the etiological agents of conjunctivitis in a total of 6763 swabs obtained over a period of four years (2001 to 2004). The prevalence of bacterial conjunctivitis was found to be 20.4% with a predominance of Staphylococcus aureus (87.2%) followed by Streptococcus pneumoniae (4.7%) and gram negative rods (E.coli + Klebsiella spp. + Pseudomonas spp.) in 8.1% swabs. For S. aureus, amikacin showed maximum sensitivity (73.2%) while for S. pneumoniae, cefotaxime (90.6%) and cefazolin (89%) were found to be highly sensitive drugs. For gram negative rods, ceftazidime (74.1%) and cefotaxime (67%) were found to be preferred options. Thus it is concluded that bacterial conjunctivitis in our hospital is predominated by S. aureus. The bacterial isolates obtained from conjunctiva have not yet attained a high level of antibiotic resistance and hence averts the need to unnecessarily start new/latest generations of antibiotic eyedrops or antibiotic combination which may lead to acquisition of resistance by these bacteria.

Bacteria↗

PubMed1988

In vitro activity of FCE 22101, imipenem, and ceftazidime against over 6,000 bacterial isolates and MIC quality control limits of FCE 22101.

Six geographically separate laboratories within the USA tested 6,198 bacterial isolates against FCE 22101 (a penem), imipenem (a carbapenem) and ceftazidime (a third-generation cephalosporin). Ninety-three percent of 2,749 Enterobacteriaceae were inhibited by FCE 22101, while 95% were susceptible to ceftazidime and 99% were susceptible to imipenem. FCE 22101 had little activity against Pseudomonas spp. but was active against most gram-positive pathogens, including enterococci. FCE 22101 MICs for standard quality control strains were defined as 0.5-2.0 micrograms/ml for Escherichia coli ATCC 25922, 2-8 micrograms/ml for Enterococcus faecalis ATCC 29212 and 0.06-0.25 microgram/ml for Staphylococcus aureus ATCC 29213.

Anti-Bacterial Agents↗

PubMed2000

[Profile of bacterial isolates and antimicrobial susceptibility: Multicenter study using a one-day cut-off].

The frequency and antimicrobial susceptibility of bacterial isolates from the largest clinical samples collected in 19 Spanish hospitals were studied. A total of 523 strains were identified and grouped by sample. Blood stream: Staphylococcus coagulase-negative (41%) and Escherichia coli (19.7%); oxacillin resistance occurred in 44% of coagulase-negative strains, strains which were also resistant to nonbetalactam agents. All antimicrobial agents tested had good activity against E. coli, with the exception of penicillins (25 to 33% susceptible). Urine: E. coli (59.1%) and Enterococcus faecalis (15%); aminoglycosides and third generation cephalosporins were the most active compounds against E. coli, whereas penicillins and cotrimoxazole were the least active. E. faecalis isolates showed low rates of resistance to the antibiotics tested and no glycopeptide-resistant strains were detected. Skin and soft tissues: Staphylococcus aureus (24.1%), Pseudomonas aeruginosa (17.7.%); oxacillin resistance occurred in 15.8% of S. aureus strains and co-resistance to nonbetalactam agents was frequently observed among these strains. Ceftazidime susceptibility was elevated among P. aeruginosa (76.9%) and the most active agents were aminoglycosides (100% susceptibility). Lower respiratory tract: P. aeruginosa (21.4%) and Haemophilus influenzae (15.5%). Aminoglycosides (88.8 to 94.4%) and ceftazidime (72%) presented the highest susceptibility rates in P. aeruginosa. All the agents tested were very active against H. influenzae (89% susceptibility). Among Gram-positive cocci, no vancomycin and/or teicoplanin-resistant strains were detected.

Bacterial Infections↗