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Applied and Environmental Microbiology Jul 2016This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana. To optimize...
UNLABELLED
This study aimed to isolate nontuberculous mycobacterial species from environmental samples obtained from some selected communities in Ghana. To optimize decontamination, spiked environmental samples were used to evaluate four decontamination solutions and supplemented media, after which the best decontamination solution and media were used for the actual analysis. The isolates obtained were identified on the basis of specific genetic sequences, including heat shock protein 65, IS2404, IS2606, rpoB, and the ketoreductase gene, as needed. Among the methods evaluated, decontamination with 1 M NaOH followed by 5% oxalic acid gave the highest rate of recovery of mycobacteria (50.0%) and the lowest rate of contamination (15.6%). The cultivation medium that supported the highest rate of recovery of mycobacteria was polymyxin B-amphotericin B-nalidixic acid-trimethoprim-azlocillin-supplemented medium (34.4%), followed by isoniazid-supplemented medium (28.1%). Among the 139 samples cultivated in the main analysis, 58 (41.7%) yielded mycobacterial growth, 70 (50.4%) had no growth, and 11 (7.9%) had all inoculated tubes contaminated. A total of 25 different mycobacterial species were identified. Fifteen species (60%) were slowly growing (e.g., Mycobacterium ulcerans, Mycobacterium avium, Mycobacterium mantenii, and Mycobacterium malmoense), and 10 (40%) were rapidly growing (e.g., Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium abscessus). The occurrence of mycobacterial species in the various environmental samples analyzed was as follows: soil, 16 species (43.2%); vegetation, 14 species (38.0%); water, 3 species (8.0%); moss, 2 species (5.4%); snail, 1 species (2.7%); fungi, 1 species (2.7%). This study is the first to report on the isolation of M. ulcerans and other medically relevant nontuberculous mycobacteria from different environmental sources in Ghana.
IMPORTANCE
Diseases caused by mycobacterial species other than those that cause tuberculosis and leprosy are increasing. Control is difficult because the current understanding of how the organisms are spread and where they live in the environment is limited, although this information is needed to design preventive measures. Growing these organisms from the environment is also difficult, because the culture medium becomes overgrown with other bacteria that also live in the environment, such as in soil and water. We aimed to improve the methods for growing these organisms from environmental sources, such as soil and water samples, for better understanding of important mycobacterial ecology.
Topics: Bacterial Proteins; Bacteriological Techniques; Buruli Ulcer; Culture Media; DNA Transposable Elements; Decontamination; Endemic Diseases; Environmental Microbiology; Ghana; Humans; Nontuberculous Mycobacteria; Specimen Handling
PubMed: 27208141
DOI: 10.1128/AEM.01002-16 -
Journal of Laboratory Physicians 2016Aeromonads are hallophillic, nonacid fast, nonspore forming, Gram-negative rods which are widely distributed in the soil, foodstuffs, and aquatic environment. Since... (Review)
Review
Aeromonads are hallophillic, nonacid fast, nonspore forming, Gram-negative rods which are widely distributed in the soil, foodstuffs, and aquatic environment. Since times immemorial, they are important zoonotic pathogens of poikilotherms but are now emerging as important human pathogens. These emerging enteric pathogens flourish in the water distribution system by forming biofilms. They possess large number of virulence factors including inherent resistance to various antibiotics and ability to form biofilms using quorum sensing. These properties make them easy pathogens for human infections. Aeromonads are important enteric pathogens, but, with the growing level of immunosuppression in the population, they have been associated with various extraintestinal infections, such as skin and soft-tissue infections, traumatic wound infections, and lower respiratory tract/urinary tract infections. The average annual incidence of bacteremia in Southern Taiwan due to Aeromonas spp. was 76 cases/million inhabitants between 2008 and 2010. However, the incidence reported from Western countries is much lower. The case fatality rate among patients with Aeromonas bacteremia ranges from 27.5 to 46%. Aeromonads are universally resistant to the narrow-spectrum penicillin group of antibiotics such as penicillin, ampicillin, carbenicillin, and ticarcillin. They are however susceptible to piperacillin, azlocillin, second and third generation cephalosporins, and carbapenems. Most of the Aeromonas species are susceptible to aminoglycosides, tetracycline, chloramphenicol, trimethoprim-sulfamethoxazole, quinolones, and monobactams. This manuscript is a comprehensive systematic review of the literature available on Aeromonas spp.
PubMed: 27013806
DOI: 10.4103/0974-2727.176234 -
FEBS Letters Jan 2016Penicillin-binding protein 3 (PBP3) from Pseudomonas aeruginosa is the molecular target of β-lactam-based antibiotics. Structures of PBP3 in complexes with azlocillin...
Penicillin-binding protein 3 (PBP3) from Pseudomonas aeruginosa is the molecular target of β-lactam-based antibiotics. Structures of PBP3 in complexes with azlocillin and cefoperazone, which are in clinical use for the treatment of pseudomonad infections, have been determined to 2.0 Å resolution. Together with data from other complexes, these structures identify a common set of residues involved in the binding of β-lactams to PBP3. Comparison of wild-type and an active site mutant (S294A) showed that increased thermal stability of PBP3 following azlocillin binding was entirely due to covalent binding to S294, whereas cefoperazone binding produces some increase in stability without the covalent link. Consistent with this, a third crystal structure was determined in which the hydrolysis product of cefoperazone was noncovalently bound in the active site of PBP3. This is the first structure of a complex between a penicillin-binding protein and cephalosporic acid and may be important in the design of new noncovalent PBP3 inhibitors.
Topics: Acylation; Azlocillin; Cefoperazone; Crystallography, X-Ray; Models, Molecular; Molecular Structure; Penicillin-Binding Proteins
PubMed: 26823174
DOI: 10.1002/1873-3468.12054 -
Journal of Biomolecular Structure &... 2015Adverse side effects of drugs are often caused by the interaction of drug molecules to targets other than the intended ones. In this study, we investigated the...
Adverse side effects of drugs are often caused by the interaction of drug molecules to targets other than the intended ones. In this study, we investigated the off-target interactions of some commercially available drugs with human α-thrombin. The drugs used in the study were selected from Super Drug Database based on the structural similarity to a known thrombin inhibitor argatroban. Interactions of these drugs with thrombin were initially checked by in silico docking studies and then confirmed by thrombin inhibition assay using a fluorescence microplate-based method. Results show that the three commonly used drugs piperacillin (anti-bacterial), azlocillin (anti-bacterial), and metolazone (anti-hypertensive and diuretic) have thrombin inhibitory activity almost similar to that of argatroban. The Ki values of piperacillin, azlocillin, and metolazone with thrombin are .55, .95, and .62 nM, respectively. The IC50 values of piperacillin, azlocillin, and metolazone with thrombin are 1.7, 2.9, and 1.92 nM, respectively. This thrombin inhibitory activity might be a reason for the observed side effects of these drugs related to blood coagulation and other thrombin activities. Furthermore, these compounds (drugs) may be used as anti-coagulants as such or with structural modifications.
Topics: Antithrombins; Arginine; Azlocillin; Humans; Kinetics; Metolazone; Molecular Docking Simulation; Molecular Structure; Pipecolic Acids; Piperacillin; Protein Binding; Protein Structure, Tertiary; Sulfonamides; Thrombin
PubMed: 24819365
DOI: 10.1080/07391102.2014.923329 -
Journal of Clinical Microbiology Feb 2012Conventional indirect drug susceptibility testing of Mycobacterium tuberculosis with liquid medium is well established and offers time-saving and reliable results. This... (Comparative Study)
Comparative Study
Conventional indirect drug susceptibility testing of Mycobacterium tuberculosis with liquid medium is well established and offers time-saving and reliable results. This multicenter study was carried out to evaluate if drug susceptibility testing (DST) can be successfully carried out directly from processed smear-positive specimens (direct DST) and if this approach could offer substantial time savings. Sputum specimens were digested, decontaminated, and concentrated by the laboratory routine procedure and were inoculated in Bactec MGIT 960 as well as Lowenstein-Jensen (LJ) medium for primary isolation. All the processed specimens which were acid-fast bacterium (AFB) smear positive were used for setting up direct DST for isoniazid (INH) and rifampin (RIF). After the antimicrobial mixture of polymyxin B, amphotericin B, nalidixic acid, trimethoprim, and azlocillin (PANTA) was added, the tubes were entered in the MGIT 960 instrument using the 21-day protocol (Bactec 960 pyrazinamide [PZA] protocol). Results obtained by direct DST were compared with those obtained by indirect DST to establish accuracy and time savings by this approach. Of a total of 360 AFB smear-positive sputum specimens set up for direct DST at four sites in three different countries, 307 (85%) specimens yielded reportable results. Average reporting time for direct DST was 11 days (range, 10 to 12 days). The average time savings by direct DST compared to indirect DST, which included time to isolate a culture and perform DST, was 8 days (range, 6 to 9 days). When results of direct DST were compared with those of indirect DST, there was 95.1% concordance with INH and 96.1% with rifampin. These findings indicate that direct DST with the Bactec MGIT 960 system offers further time savings and is a quick method to reliably detect multidrug resistance (MDR) cases.
Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Specimen Handling; Sputum; Time Factors; Tuberculosis, Multidrug-Resistant
PubMed: 22162558
DOI: 10.1128/JCM.05188-11 -
Clinical Microbiology and Infection :... May 2012Phage lysin was evaluated as a substitute for antibiotics in sputum samples processed by a modified Petroff's method for the detection of Mycobacterium tuberculosis with...
Phage lysin was evaluated as a substitute for antibiotics in sputum samples processed by a modified Petroff's method for the detection of Mycobacterium tuberculosis with the MGIT 960 system. One hundred and fifty sputum samples were processed, inoculated onto two slopes of Lowenstein-Jensen medium, and divided in to two aliquots of 0.5 mL each. One aliquot was added to 7 mL of MGIT medium containing polymyxin B, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) (MGIT-PANTA) and the other was added to 7 mL of MGIT medium containing 0.8 mL of lysin (MGIT-Lysin). The samples were randomized and incubated at 37°C in the MGIT 960 system. The sensitivity and specificity of MGIT-Lysin were 97% and 88%, respectively, as compared with MGIT-PANTA. The average times to detection with MGIT-Lysin and MGIT-PANTA were 9.3 and 8.6 days, respectively. The rate of contamination with MGIT-PANTA and MGIT-Lysin were 16% and 7.3%, respectively. Phage lysin can be substituted for antibiotics in processed sputum samples for the detection of M. tuberculosis.
Topics: Anti-Bacterial Agents; Bacteria; Bacteriological Techniques; Bacteriophages; Culture Media; Decontamination; Humans; Lysogeny; Mycobacterium tuberculosis; Sensitivity and Specificity; Sputum; Tuberculosis, Pulmonary
PubMed: 21883661
DOI: 10.1111/j.1469-0691.2011.03601.x -
Journal of Molecular Recognition : JMR 2011Single-nanopores have recently been used to electrically detect a wide range of analytes. Similarly, using electrophysiology, we demonstrate how a system comprised of an...
Single-nanopores have recently been used to electrically detect a wide range of analytes. Similarly, using electrophysiology, we demonstrate how a system comprised of an ion channel formed by α-hemolysin (α-HL) and single-cyclic γ-cyclodextrin (γ-CD) molecule permits the detection of, and differentiation between three different antibiotics from the β-lactam family. Specifically, histograms of the time between the successive binding events, and the residence time distributions of the antibiotic in the γ-CD molecular adapter vary with the antibiotic type. The results show that the association times of amoxicillin, azlocillin, and ampicillin are τ(on) = 2.1 ± 0.2, 2.2 ± 0.3, and 3.1 ± 0.4 ms, respectively. Interestingly, we found that the residence time of the bulkier and negatively charged azlocillin (τ(off) = 0.008 ± 0.0005 ms) is much less than that of ampicillin (τ(off) = 0.07 ± 0.005 ms) and amoxicillin (τ(off) = 0.1 ± 0.02 ms), even though the γ-CD-α-HL complex is anionic selective. The data were also used to estimate the standard free energy of binding between ampicillin to γ-CDs binding (-12 kJ mol(-1) [corrected]). The difference in association times might be due to γ-CDs-imposed steric hindrance or an energetically more expensive desolvation step for the antibiotics to gain access to the binding site in the CD. We suggest that this technique may be used to detect other analytes used in pharmaceutical applications.
Topics: Amoxicillin; Ampicillin; Anti-Bacterial Agents; Azlocillin; Electricity; Hemolysin Proteins; Ion Channel Gating; Kinetics; Molecular Probe Techniques; Nanopores; Recombinant Proteins; Stochastic Processes; Time Factors; beta-Lactams; gamma-Cyclodextrins
PubMed: 21360610
DOI: 10.1002/jmr.1038 -
The International Journal of... Feb 2011We assessed the effect of a double concentration of supplemental polymyxin B, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) added to the...
We assessed the effect of a double concentration of supplemental polymyxin B, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) added to the Mycobacterial Growth Indicator Tube (MGIT) on contamination and positivity rates in 216 sputum cultures. Contamination rates were respectively 12.9% and 5.5% for samples processed using standard and double PANTA concentrations (P = 0.0001, McNemar's test). Thirty-five per cent of cultures performed using standard PANTA and 36.5% of those performed using two-fold PANTA concentrations were positive for Mycobacterium tuberculosis, compared to 25.9% of cultures inoculated on Ogawa medium. These results suggest that the use of MGIT with 2× PANTA may be useful in reducing culture contamination without reducing the diagnostic yield.
Topics: Amphotericin B; Anti-Bacterial Agents; Azlocillin; Bacteriological Techniques; Culture Media; Disposable Equipment; Dose-Response Relationship, Drug; Equipment Contamination; Humans; Mycobacterium tuberculosis; Nalidixic Acid; Polymyxin B; Predictive Value of Tests; Prospective Studies; Sputum; Trimethoprim; Tuberculosis, Pulmonary
PubMed: 21219695
DOI: No ID Found -
BMC Evolutionary Biology Jun 2010Comparative phylogeography of sympatric sibling species provides an opportunity to isolate the effects of geography and demographics on the evolutionary history of two...
BACKGROUND
Comparative phylogeography of sympatric sibling species provides an opportunity to isolate the effects of geography and demographics on the evolutionary history of two lineages over the same, known time scale. In the current study, we investigated the phylogeographic structure of two zopherid beetle species, Phloeodes diabolicus and P. plicatus, where their ranges overlap in California's Transverse Ranges.
RESULTS
Although P. diabolicus and P. plicatus share similar habitats with largely overlapping distributions, the results of this study revealed different evolutionary histories for each species since divergence from their most recent common ancestor. In general, P. plicatus had higher genetic diversity, and more among population isolation than P. diabolicus. The mismatch distributions indicated that one major difference between the two species was the timing of population expansion. This result was consistent with genetic patterns revealed by the Phist values and genetic diversity. Lastly, there were no parallel genetic breaks at similar geographic barriers between the species.
CONCLUSIONS
Our data revealed that differential demographics rather than geography were responsible for the genetic patterns of the two species.
Topics: Animals; Azlocillin; California; Coleoptera; Ecosystem; Evolution, Molecular; Genetic Variation; Genetics, Population; Geography; Models, Genetic; Phylogeny; Sequence Analysis, DNA
PubMed: 20573263
DOI: 10.1186/1471-2148-10-195 -
Molecular Ecology Jul 2010The repeated formation and loss of land-bridges during the Pleistocene have had lasting impacts on population genetic structure. In the tropics, where island populations...
The repeated formation and loss of land-bridges during the Pleistocene have had lasting impacts on population genetic structure. In the tropics, where island populations persisted through multiple glacial cycles, alternating periods of isolation and contact are expected to have driven population and taxonomic divergence. Here, we combine mitochondrial and nuclear sequence data with microsatellites to dissect the impact of Pleistocene climate change on intra-specific diversification in the horseshoe bat Rhinolophus affinis. This taxon shows considerable morphological and acoustic variation: two parapatric subspecies (himalayanus and macrurus) occur on mainland China and a third (hainanus) on Hainan Island. Our phylogeographic reconstruction and coalescent analyses suggest the island subspecies formed from an ancestral population of himalayanus via two colonization events c. 800,000 years before present. R. a. hainanus then recolonized the mainland, forming macrurus and thus a secondary contact zone with himalayanus. Finally, macrurus recolonized Hainan following the LGM. We found that all three biological events corresponded to known periods of land-bridge formation. Evidence of introgression was detected between macrurus and both its sister taxa, with geographical proximity rather than length of separation appearing to be the biggest determinant of subsequent genetic exchange. Our study highlights the important role of climate-mediated sea level changes have had in shaping current processes and patterns of population structure and taxonomic diversification.
Topics: Animals; Azlocillin; Cell Nucleus; China; Chiroptera; Climate; Cluster Analysis; DNA, Mitochondrial; Evolution, Molecular; Female; Gene Flow; Genetic Speciation; Genetic Variation; Genetics, Population; Genotype; Geography; Microsatellite Repeats; Phylogeny; Sequence Analysis, DNA
PubMed: 20561192
DOI: 10.1111/j.1365-294X.2010.04704.x