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PubMed2026

Comparative genomic analysis of Streptococcus parasuis and Streptococcus suis reveals mobile element-associated enrichment of antimicrobial resistance and lack of detectable same-MGE colocalization with virulence-associated genes within stable species boundaries.

Streptococcus suis is a major porcine pathogen and a zoonotic agent that causes meningitis and septicemia in humans. Streptococcus parasuis, a recently recognized close relative, remains poorly characterized with regard to its clinical significance and genomic features. In this study, we generated a single-contig closed genome assembly with genome-wide DNA methylation profiles for S. parasuis strain A1, isolated from a diseased pig in Xinjiang, China, and complemented in silico genomic predictions with isolate-level experimental validation of antimicrobial resistance (AMR) genotypes, virulence genotypes, and phenotypic susceptibility for this reference strain. Using this high-quality genome as a reference anchor, we performed comparative genomic analyses across 195 streptococcal genomes, comprising 15 S. parasuis and 180 S. suis strains, to distinguish genome-level co-occurrence of resistance and virulence determinants from their physical colocalization on the same mobile genetic element (MGE).Species boundaries remained clearly delineated at the genomic level, with a median interspecies average nucleotide identity (ANI) of approximately 86.0%, compared with intraspecies ANI medians of 97.5% for S. parasuis and 96.2% for S. suis. Pangenome analysis identified 12,693 gene clusters, of which 1086 were core clusters, and functional annotation revealed significant differences in accessory gene repertoires between the two species. Within this stable genomic framework, S. parasuis genomes carried a higher AMR gene burden; strain A1 harbored 10 AMR genes, multiple virulence-associated genes, three genomic islands, and eight prophage regions. For strain A1, PCR validation confirmed six AMR genes and six virulence genes, and disk diffusion testing demonstrated a multidrug-resistant phenotype consistent with the genotypic profile.Among 235 predicted mobile elements, 19 harbored AMR genes and seven carried Virulence Factor Database (VFDB) homologs, but none carried both categories simultaneously. This finding reflects a lack of detectable same-MGE colocalization under the applied annotation and assembly framework; it should not be interpreted as evidence of biological physical decoupling. Under a random-placement model, the expected number of co-carrying regions was only 0.57, and the probability of observing zero co-carrying regions was P = 0.55. This negative result should be interpreted with caution, given the limited number of cargo-bearing regions and the predominantly draft status of most genomes. Furthermore, the A1 genome contained multiple restriction-modification systems, showed depletion of several methylation motif families in mobile regions, and had limited CRISPR spacer matching evidence, suggesting prior exposure to the relevant sequence space. None of the genomes met our predefined criteria for whole-genome convergence.Collectively, our results support a model in which S. parasuis accumulates AMR-related genes in a modular fashion via mobile elements within stable species boundaries, with no detectable same-MGE colocalization of AMR and virulence determinants under our analytical pipeline. These findings imply that AMR surveillance strategies for this species should prioritize tracking mobile genetic elements rather than inferring wholesale genomic convergence toward S. suis.

Streptococcus suis↗
PubMed1990

Studies on heterocyclic compounds: spiro [indole-3,2'-thiazolidine] derivatives. II. Antimicrobial activity of halogenated 3'-phenylspiro 3H-indole-3,2'-thiazolidine -2,4 (1H)-diones.

The following polyhalogenated 3'-phenyl 3H-indole-3,2'-thiazolidine -2,4' (1H)-dione of general formula (A) were synthesized and screened for antimicrobial activity. (formula: see text) where: X = H (I, III, V, VII, IX, XI), CH3 (II, IV, VI, VIII, X, XII); Y = H (I, II), 2,4-F2 (III, IV), 2,4-Cl2 (V, VI), 3,4-Cl2 (VII, VIII), 2,6-Cl2 (IX, X), 2,4,6-Cl3 (XI, XII). The general synthetic route involves the preparation of variously substituted isatin-3-imines, which are subjected to cyclocondensation with thioglycolic acid to give compounds I, III, V, VII, IX, XI, or thiolactic acid to give compounds II, IV, VI, VII, X, XII. The prepared compounds were screened against S. aureus, B. cereus, M. paratuberculosis, E. coli, Pr. mirabilis, Ps. aeruginosa, C. albicans, S. cerevisiae, A. niger by a disk-diffusion assay (Kirby-Bauer modified). The results of the antimicrobial screening showed that the polyhalogenated derivatives of type (A) exhibited varying degrees of activity against Gram-positive, Gram-negative bacteria, and fungi. Compound (III) showed a significant activity toward A. niger, moreover compound (IV) was active toward C. albicans. Compound (IX) was very active toward S. typhi and Ps. aeruginosa. Compounds (VII), (IX) and (XII) were very active toward M. paratuberculosis.

Anti-Bacterial Agents↗
PubMed2002

Shifting serotypes, plasmid profile analysis and antimicrobial resistance pattern of shigellae strains isolated from Kolkata, India during 1995-2000.

One hundred and sixty-six shigellae strains, isolated from stool samples of paediatric patients (< 5 years old) at a Childrens' Hospital in Kolkata, India during the period of 1995-2000 were examined for serotyping, drug resistance pattern and plasmid profiles. Sh. flexneri (58 %) was found to be commonest isolate of total shigellae, followed by Sh. sonnei (28 %), Sh. boydii (9%) and Sh. dysenteriae (5%). This profile of species was in sharp contrast to the picture obtained before 1995, when Sh. dysenteriae 1 predominated over Sh. flexneri. In Sh. flexneri strains, Sh. flexneri 2a (35%) was the most prevalent serotype, following Sh. flexneri 3a (31%), Sh. flexneri 6 (14%), Sh. flexneri 2b (11%) and Sh. flexneri 4 (9%). Resistance patterns of the strains to 12 commonly used antimicrobial agents and minimum inhibitory concentrations (MICs) of the antibiotics were also tested. All strains were found uniformly susceptible to norfloxacin, but more than 90% strains were resistant to tetracycline, co-trimoxazole and 67% strains were resistant to ampicillin. Resistance to amoxicillin, chloramphenicol and nalidixic acid was found in 55% (range 45-74%), 46% (range 40-60%) and 29% (range 15-40%) strains respectively. Overall, shigellae strains showed statistically significant increase in resistance against tetracycline, nalidixic acid and furazolidone (P < 0.05) over the years of this study. This indicates decreased efficacy of furazolidone, cotrimoxazole and nalidixic acid for the empirical treatment of shigellosis in Kolkata. Although a few strains showed intermediate susceptibility to ciprofloxacin (4%) and cefotaxime (10%) by disk diffusion test, but the MICs of those antibiotics were within the normal limits. Almost 57% of the strains were resistant to four or more drugs with high MICs of the antibiotics. Plasmid profile analysis revealed presence of large plasmid of 220 kb in majority of the strains except in Sh. sonnei and a correlation between presence of smaller plasmids and shigellae serotypes. Hence this study reports epidemiological change of shigellae species in Kolkata, India with regard to serotypes and antibiotic resistance patterns.

Anti-Bacterial Agents↗
PubMed2003

The impact of Helicobacter pylori resistance on the efficacy of a short course pantoprazole based triple therapy.

BACKGROUND: Many of the currently used Helicobacter pylori eradication regimens fail to cure the infection due to either antimicrobial resistance or poor patient compliance. Those patients will remain at risk of developing potentially severe complications of peptic ulcer disease. AIM: We studied the impact of the antimicrobial resistance on the efficacy of a short course pantoprazole based triple therapy in a single-center pilot study. METHODS: Forty previously untreated adult patients (age range 20 to 75 years, 14 males) infected with Helicobacter pylori and with inactive or healing duodenal ulcer disease were assigned in this open cohort study to 1 week twice daily treatment with pantoprazole 40 mg, plus clarithromycin 250 mg and metronidazole 400 mg. Helicobacter pylori was assessed at entry and 50 3 days after the end of treatment by rapid urease test, culture and histology of gastric biopsies. The criteria for eradication was a negative result in the tests. Susceptibility of Helicobacter pylori to clarithromycin and metronidazole was determined before treatment with the disk diffusion test. RESULTS: One week treatment and follow up were complete in all patients. Eradication of Helicobacter pylori was achieved in 35/40 patients (87.5%) and was higher in patients with nitroimidazole-susceptible strains [susceptible: 20/20 (100%), resistant: 10/15 (67%)]. There were six (15%) mild adverse events reports. CONCLUSIONS: A short course of pantoprazole-based triple therapy is well tolerated and effective in eradicating Helicobacter pylori. The baseline metronidazole resistance may be a significant limiting factor in treatment success.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMedDate not supplied

Effect of two balanced salt solutions on the bioavailability of ofloxacin and ciprofloxacin.

Metal ions, which are present in ocular fluids, can significantly decrease the bioavailability of fluoroquinolones. This in vitro study investigated the bioavailability of ofloxacin and ciprofloxacin in the presence of two balanced salt solutions, BSS-Plus and AMO Endosol, commonly used as irrigants in cataract surgery. Minimum inhibitory concentrations (MICs) and antibiotic susceptibility were determined through broth dilution methods and a standard disk diffusion bioassay with Escherichia coli. Although neither solution affected the in vitro antimicrobial activity of ofloxacin, both markedly decreased that of ciprofloxacin. In BSS-Plus and AMO Endosol, the MICs of ciprofloxacin for several ocular isolates were increased, indicating decreased susceptibility to that drug; the activity of ciprofloxacin against E. coli was also decreased. Because the composition of BSS-Plus is similar to that of human aqueous humor, the clinical efficacy of ofloxacin may be unaffected by the ionic composition of the aqueous humor. In contrast, because the antimicrobial activity of ciprofloxacin was diminished in BSS-Plus, the clinical efficacy of this fluoroquinolone against deep ocular infections may not be as great as indicated by standard laboratory antibiotic susceptibility testing.

Anti-Infective Agents↗
PubMed2001

[Antimicrobial activities and mechanisms of carbapenem resistance in clinical isolates of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter spp].

We tested the antimicrobial activities of meropenem (MEPM), imipenem (IPM), panipenem (PAPM), piperacillin (PIPC), cefepime (CFPM), aztreonam (AZT), amikacin (AMK), and levofloxacin (LVFX) against 106 clinical Pseudomonas aeruginosa isolates and 64 clinical Acinetobacter spp. isolates with reduced susceptibility to carbapenems. Using NCCLS breakpoints, the percentages of P. aeruginosa strains susceptible to AMK and Acinetobacter spp. strains susceptible to LVFX were found to be 51.1% and 55.6%, respectively, which represented the highest activity among 8 antimicrobial agents in each organism. Referring to the correlations among MICs of carbapenems, MEPM showed a higher activity than IPM and PAPM in both organisms; 29 of the 94 strains (30.9%) of IPM-resistant P. aeruginosa were susceptible to MEPM. Further study for resistance mechanisms to carbapenems by the disk diffusion method using 2-mercaptopropionic acid revealed that 8 of the 64 Acinetobacter spp. isolates (12.5%) were metallo-beta-lactamase producers, while none of 106 P. aeruginosa isolates were metallo-beta-lactamase producers. PCR analysis using blaIMP-specific primers confirmed that 4 of the 8 metallo-beta-lactamase-producing Acinetobacter spp. isolates detected by the disk diffusion method were carrying the blaIMP gene. The identification of metallo-beta-lactamase-producing Acinetobacter spp. isolates implies that metallo-beta-lactamase genes have been disseminated among various gram-negative pathogens.

Acinetobacter↗
PubMedDate not supplied

Spectrum and antibiotic resistance of uropathogens isolated from hospital and community patients with urinary tract infections in two large hospitals in Kuwait.

OBJECTIVES: To determine the spectrum of microbial etiology and antibiotic resistance pattern of the uropathogens that cause urinary tract infections in 2 large teaching hospitals in Kuwait over a period of 1 year. MATERIALS AND METHODS: The Vitek identification card system was used to identify the uropathogens. Susceptibility of the isolates against 18 antibiotics was performed by the microbroth dilution method using the Vitek automated system. In addition, gram-positive bacteria were tested in parallel by the disk diffusion technique. RESULTS: The six overall most common isolates were: Escherichia coli, accounting for 47% of isolates in both hospitals, followed by Candida spp. (10.8%), Klebsiella pneumoniae (9.6%), Streptococcus agalactiae (GBS; 9.5%), Enterococcus faecalis (4.2%) and Pseudomonas aeruginosa (4.1%). Amikacin provided the widest coverage amongst all the antibiotics tested followed by ciprofloxacin, gentamicin and piperacillin-tazobactam. For the gram-negatives, high resistance (26-63%) to the beta-lactam antibiotics was noted, especially to ampicillin, amoxicillin-clavulanic acid, cephalothin and cefuroxime. Resistance to trimethoprim-sulfamethoxazole was also high. None of the enterococci was resistant to the glycopeptides, but 38-60% of the Staphylococcus haemolyticus were resistant to vancomycin or teicoplanin. CONCLUSION: These data show the high level of antimicrobial resistance amongst the uropathogens causing urinary tract infection in the two hospitals studied.

Drug Resistance, Bacterial↗
PubMed1993

[Antimicrobial sensitivity of some gram-negative bacterial strains causing hospital or community-acquired infections].

The susceptibility to various antimicrobics of E. coli, Klebsiella, S. typhimurium, Pseudomonas, Proteus and Edwardsiella strains causing hospital or community acquired infections were investigated by Kirby-Bauer's disk diffusion method. It was found that ampicillin was the least and quinolones were the most effective antimicrobics for the both hospital and community acquired infections. In general, the antimicrobic resistance was significantly increased for the hospital isolates.

Anti-Bacterial Agents↗
PubMed1978

Cefamandole in treatment of peritonitis.

Cefamandole was evaluated as the sole antimicrobial agent used to treat bacterial peritonitis in 113 patients. Dosage varied between 1 and 2 g given intravenously every 6 hr. Laparotomy for excision of infected or gangrenous tissues, closure of gastrointestinal perforations, or drainage of an established abscess was required in 99 of the cases. A good clinical response was obtained in 107 patients, or 95% of the total group. Of the six deaths only one could be attributed to infection. No evidence of renal, hepatic, or hematopoietic toxicity was noted. There were no allergic reactions, although 13 patients (12%) developed phlebitis in a vein used for antibiotic administration. Bacteriological studies revealed aerobic peritonitis in 99% of the patients, with anaerobe participation in 60% of these cases. Sensitivity testing by the disk diffusion and tube dilution methods confirmed the appropriateness of cefamandole therapy; 91% of the gram-negative rods and 61% of the anaerobes were susceptible. From results of this study, it would appear that cefamandole is a reliably effective antibiotic for use in treatment of most forms of acute peritonitis. Its role in surgical prophylaxis may be even more promising.

Adult↗
PubMed1990

Studies on heterocyclic compounds: spiro [indole-3,2'-thiazolidine] derivatives. Antimicrobial activity of monohalogenated 3'-phenylspiro 3H-indole-3,2'-thiazolidine-2,4' (1H)-diones.

The following halogenated 3'-phenyl [3H-indole-3,2'-thiazolidine]-2,4'(1H)-dione of general formula (A) were synthesized and screened for antimicrobial activity. (formula: see text) where: X = H (I, III, V, VII, IX, XI, XIII, XV), CH3 (II, IV, VI, VIII, X, XII, XIV, XVI); Y = H (I, II), 3-F (III, IV), 2-Cl (V, VI), 3-Cl (VII, VIII), 4-Cl (IX, X), 2-Br (XI, XII), 3-Br (XIII, XIV), 4-Br (XV, XVI). The synthetic approach involves the preparation of variously substituted Schiff-bases of indol-2,3-dione, which then are subjected to cyclocondensation with alpha-mercaptoalkanoic acids, to give spirothiazolidinones of type (A). The prepared compounds were screened against S. aureus, B. cereus, M. paratuberculosis, E. coli, S. typhi, Pr. mirabilis, Ps. aeruginosa, C. albicans, S. cerevisiae, A. niger by a disk-diffusion assay (Kirby-Bauer modified. The results of the antimicrobial screening showed that the prepared compounds exhibited varying degrees of activity against Gram-positive, Gram-negative bacteria, and fungi. 3-Fluoro-derivative (III) showed inhibitory activity especially toward S. aureus and C. albicans. Chloroderivatives (VII) and (VIII) showed broad-spectrum "in vitro" antimicrobial activity, and were especially inhibitory toward S. aureus, E. coli, and S. Typhi. Fluoro-derivative (IV) and bromo-derivatives (XIII) and (XIV) possessed marked antimicrobial activity against M. paratuberculosis.

Anti-Bacterial Agents↗
PubMed1997

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.

Agar↗
PubMed2006

Heliconols A-C: antimicrobial hemiketals from the freshwater aquatic fungus Helicodendron giganteum.

[Structure: see text] Cultures of the freshwater aquatic fungus Helicodendron giganteum afforded three new compounds, heliconols A-C (1-3), that contain an unusual reduced furanocyclopentane unit. The structures of these metabolites were assigned by analysis of 1D and 2D NMR data. The absolute configuration of heliconol A (1) was assigned by single-crystal X-ray crystallographic analysis of its dibromobenzoate derivative. Heliconol A showed antifungal and antibacterial activities in disk diffusion assays.

Anti-Bacterial Agents↗
PubMed1998

Toxin production and antimicrobial resistance of Escherichia coli river water isolates.

OBJECTIVES: To establish the types of E. coli isolates that are found in river water around Nairobi and to assess the potential risk of use of this water to human health. DESIGN: Multiple stratified sampling was carried out. Surface sampling was used in the entire study. SETTING: The study was carried out on river waters surrounding Nairobi, Kenya. SUBJECTS: Forty Escherichia coli strains isolated from river water. MAIN OUTCOME MEASURES: Serotyping, toxin gene tests and susceptibility to tetracyclines, ampicillin, chloramphenicol and kanamycin were analysed. RESULTS: None of the isolates could be specifically serotyped using the available antisera. Toxin gene production tests using the colony hybridisation technique revealed that nine (22.5%) of the strains were positive for heat stable (ST) toxin, seven (17.5%) to the heat labile (LT) toxin and two (5%) to both. Using the Agar Disk Diffusion technique, eighty per cent of the strains were susceptible to all four antibiotics, while twenty per cent of the strains showed multiple resistance. None of the strains was resistant to all four antibiotics while no strain showed resistance to kanamycin. CONCLUSION: None of the E. coli isolates was serotypable and it was therefore not possible to determine whether serologically identical strains of ETEC were haboured by man or animals. Toxin gene tests results showed that there is some risk of infection by diarrhoea causing ETEC to man and animals. Toxin gene tests results showed that there is some risk of infection by diarrhoea causing ETEC to man and animals if they consume this water untreated and there is evidence to show resistance of bacteria to antibiotics, hence appropriate health measures should be adhered to.

Bacterial Toxins↗
PubMed2002

Comparative antimicrobial spectrum and activity of the desfluoroquinolone BMS284756 (T-3811) tested against non-fermentative Gram-negative bacilli.

OBJECTIVE: To compare the in vitro activity of BMS284756, a desfluoroquinolone, with four fluoroquinolones against 129 Pseudomonas aeruginosa strains, 97 Stenotrophomonas/Burkholderia group strains and 43 Acinetobacter spp. strains by three in vitro test methods. METHODS: The activity of BMS284756 was determined using the NCCLS reference broth microdilution method and E test (AB Biodisk, Solna, Sweden). These methods were compared for test accuracy, and 5-microg disk zone diameters were compared for interpretative accuracy using the susceptible breakpoint of < or =4 mg/L recommended by the manufacturer. All strains tested were derived from the 1999-2000 SENTRY Antimicrobial Surveillance Program organism collection. RESULTS: Comparative quinolone potency against P. aeruginosa was as follows: ciprofloxacin (MIC50, 0.25 mg/L) > gemifloxacin (MIC50, 0.5 mg/L) > levofloxacin = gatifloxacin (MIC50, 1 mg/L) > BMS284756 (MIC50, 4 mg/L). The MIC50 value for BMS284756 versus Stenotrophomonas/Burkholderia group was 2 mg/L. This potency was similar to that of other quinolones reported previously. The MIC50 results for the Acinetobacter spp. were ciprofloxacin at >2 mg/L, levofloxacin, gatifloxacin and gemifloxacin at 4 mg/L, and BMS284756 at >4 mg/L, all intermediate or resistant concentrations. The E test results compared favorably with the reference dilution test results for P. aeruginosa, Stenotrophomonas/Burkholderia group, and Acinetobacter spp., with an overall essential agreement of 97.0% +/- 2 log2 dilution steps. E test MIC results tended to be slightly lower when testing Stenotrophomonas/Burkholderia group strains. The disk diffusion method correlated well for P. aeruginosa (r = 0.94), Stenotrophomonas/Burkholderia group (r = 0.84) and Acinetobacter spp. (r = 0.99) strains. CONCLUSIONS: BMS284756 was generally less active than other comparison quinolones when tested against non-fermentative Gram-negative bacilli. Its spectrum remains equivalent only if dosing schedules substantiate a proposed susceptible breakpoint of < or =4 mg/L.

Anti-Infective Agents↗
PubMed1997

[Laboratory-evaluation of antimicrobial susceptibility testings to detect vancomycin-resistant enterococci].

The emergence and dissemination of vancomycin-resistant enterococci (VRE) emphasizes the need for laboratories to be able to correctly detect them. The study described was conducted to evaluate the test methods presently available in Japan to discriminate between the isolates of VRE and those susceptible (VSE). Among the phenotypic test methods evaluated, an agar screening method which utilized 8 micrograms per ml of vancomycin in Mueller-Hinton agar plate appeared to have a sufficient accuracy. When 23 isolates of vanA positive, 31 of vanB positive, 4 of both positive and 60 of both negative were tested, the sensitivity and specificity to detect VRE were estimated to be 98.3% and 100%, respectively. Also, all the VRE isolates were interpreted as being resistant or intermediate by the E test recently approved in Japan, when the results were read after 48 hr-incubation. Whereas, two disk diffusion tests, Showa disk and NCCLS-based Sensi-disc, were evaluated, but both methods failed to discriminate between VRE and VSE, in particular, between the isolates with vanB positive and negative. The automated system, Vitek GPS-TA produced high frequencies of very major errors; 8.7% for vanA positives and 58% for vanB positives. A total of 1,214 enterococcal isolates from multisite laboratories in Japan, comprising 7 different species, were first tested onto agar screening test plates, but none of isolates represented phenotypic vancomycin resistance. With these results, it can be recommended to detect VRE in clinical microbiology laboratories as follows: First, all the enterococcal isolates will be tested onto the agar screening plates or by the E test. Then, if the isolate is interpreted as being resistant or intermediate, the laboratory should confirm whether it is positive for vanA or vanB by polymerase chain reaction (PCR) specified.

Anti-Bacterial Agents↗
PubMed1999

Drug-resistant Streptococcus pneumoniae in the Lebanon: implications for presumptive therapy.

A total of 50 consecutive clinical isolates of Streptococcus pneumoniae, collected between 1996 and 1998, were tested against six antimicrobial agents using the E-test. The percentages of fully resistant (R) and intermediately-R strains, respectively, were: benzyl penicillin 18 and 38%, amoxycillin-clavulanate 6 and 12%, cefuroxime 22 and 16%, ceftriaxone 2 and 16%, and clarithromycin 10%. Fully and or intermediately multidrug-resistance (two or more drugs) was seen in 44% of the isolates, 18% being fully resistant. The MIC breakpoint for cefaclor is not defined by the National Committee for Clinical Laboratory Standards (NCCLS) but MICs showed that: 76% of the isolates had an MIC of < or = 8 mg/l, 4% had an MIC of 16 mg/l and 20% had an MIC of > or = 32 mg/l. There was agreement between the E-test Pen MIC results and the 1 microg oxacillin (oxa) disk diffusion screen test for the 22 susceptible and the nine fully R strains but not for the 19 strains with Pen MICs between 0.1 and 1 mg/l; this shows the importance of MIC determination in such isolates. Penicillin and multiply antibiotic-resistant pneumococci are spreading in Lebanon, emphasizing the necessity to reconsider current treatment regimens in this country.

Anti-Bacterial Agents↗
PubMed2003

Microbial contamination of disinfectants and antiseptics in four major hospitals in Trinidad.

OBJECTIVE: To assess the microbial contamination of disinfectants and antiseptics in major hospitals on the Caribbean island of Trinidad. METHODS: For this cross-sectional study, disinfectants and antiseptics were sampled from the pharmacy departments, the pediatric/neonatal wards, and the surgical wards of four hospitals. The samples were cultured for aerobic bacteria on nutrient agar using the surface plating method. The antibiotic sensitivity of bacterial isolates was determined by the disk diffusion method, using 14 antimicrobial agents. We studied a total of 180 disinfectant/antiseptic samples: 60 of chlorhexidine gluconate (Hibitane), 60 of chlorhexidine gluconate and cetrimonium bromide (Savlon), and 60 of methylated spirit. RESULTS: Of the 180 samples studied, 11 of them (6.1%) were contaminated by aerobic bacteria. All bacteria isolated were Pseudomonas spp. Of the 11 contaminated samples, 6 of them (54.5%) occurred at the pharmacy level while 5 (45.5%) were from diluted pre-use or in-use samples in the pediatric/neonatal wards or the surgical wards. Chlorhexidine gluconate and cetrimonium bromide accounted for 9 of the 11 contaminated disinfectants/antiseptics (81.8%), and chlorhexidine gluconate accounted for the remaining 2 (18.2%). Only two of the four hospitals had contaminated disinfectant/antiseptic samples. All 24 isolates of Pseudomonas spp. tested were resistant to one or more of the 14 antimicrobial agents tested, with the prevalence of resistance to ciprofloxacin, norfloxacin, tobramycin, and gentamicin being 58.3%, 50.0%, 45.8%, and 41.7%, respectively. CONCLUSIONS: Our results show that contaminated disinfectants/antiseptics pose a health risk to patients, particularly in the pediatric and surgical wards. The high prevalence of resistance to antimicrobial agents exhibited by the Pseudomonas spp. that were isolated is of special therapeutic concern.

Anti-Infective Agents, Local↗
PubMed2002

Antibiotic susceptibility patterns for environmental streptococci isolated from bovine mastitis in central California dairies.

Environmental streptococci are frequently isolated from bovine mastitis in dairy cows with only limited information available on the antimicrobial susceptibility of these organisms. A total of 362 environmental streptococci isolated from cases of bovine mastitis from the central San Joaquin Valley of California over a 3-yr period were used in the study. Overall, 39.9% of the strains tested were Streptococcus uberis, 42.2% were Streptococcus dysgalactiae, and 11.1% were Enterococcus spp. The antimicrobial susceptibility for these organisms was determined for the following antimicrobial agents: penicillin, ampicillin, cephalothin, ceftiofur, penicillin + novobiocin, erythromycin, pirlimycin, tetracycline, and sulfadimethoxine. Results demonstrate substantial differences in the susceptibility patterns for the various organisms collectively referred to as the environmental streptococci. The MIC90 for penicillin was 0.06 microg/ml for 152 strains of S. dysgalactiae compared with 0.25 microg/ml for 133 strains of S. uberis. However, the Enterococcus spp. were the most resistant organisms tested. These data also indicate that the use of interpretive criteria based on human data may provide misleading results. In conclusion, these data confirm that the environmental streptococci are a diverse group of organisms comprised of several different genera and species and that identification of environmental streptococci to the species level is needed to appropriately modify control methods. Moreover, the use of the agar disk diffusion (Kirby-Bauer) susceptibility test for agents with human-based interpretive criteria is contraindicated, and these tests should only be performed with agents with mastitis specific interpretive criteria.

Animals↗