MOSP - Macao Scientific Publishers

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Antimicrobial susceptibility of Clostridium difficile isolated from different sources of Imam Reza Hospital, Tabriz

Mohammad Taghi Akhi, * Tahere Pirzade, Behruz Naghili, and Mortaza Gojazade

Abstract: The aim of this study was to determine antibiotic susceptibility of Clostridium difficile isolated from different sources. Two hundred stool samples of staff, patients (at admission to the wards and the same patients after seven days of hospitalization), and 135 samples of hospital environment were collected. Three standard methods including direct plating onto cycloserine-cefoxitin fructose agar, alcohol shock and enrichment culture with 0.1% sodium taurocholate were used to isolate C. difficile. All C. difficile isolates identified by biochemical tests and were tested by disk diffusion agar using 15 antibiotic disks. MIC of isolates was determined for vancomycin and metronidazol by Etest. Seventy C. difficile were isolated from different sources. No resistant isolates to vancomicin and metronidazol were detected by disk diffusion or Etest. The rate of recovery by 0.1% sodium taurocholate enrichment method and alcohol shock was significantly higher than those by CCFA (pv 0.02, pv 0.04).[...] Read More.

Keywords: Clostridium difficile, antibiotic resistance, vancomycin, metronidazol.

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Detection of inducible clindamycin resistance by an automated system in a tertiary care hospital

Jethwani Urmi N.*, Mulla Summaiya A., Shah Latika N. and Panwala Tanvi R.

Abstract: Clindamycin is commonly used in treatment of erythromycin resistant Staphylococcus aureus causing skin and soft tissue infections. In vitro routine tests for clindamycin susceptibility may fail to detect inducible clindamycin resistance due to ‘erm’ genes resulting in treatment failure thus necessitating the need to detect such resistance by a rapid method. In the era of automation, vitek-2 system provides a panel for detection of inducible clindamycin resistance with conjunction of other antimicrobial susceptibility testing. The present study evaluated the performance of a vitek-2 card for detection of inducible clindamycin resistance in a tertiary care hospital. Non-duplicate clinical isolates of hundred S. aureus were obtained from various clinical samples. Antimicrobial susceptibility testing was carried out, including detection of clindamycin resistance and methicillin resistance pattern by vitek-2 identification and antimicrobial susceptibility testing (ID/AST) system by using AST-GP67 card. The results were compared to those of D-test as per CLSI guidelines on erythromycin resistant isolates. EPI INFO software, Licensed by CDC Atlanta was used for analysis of data. The sensitivity and specificity for the vitek-2 card was 95.4 and 100%, respectively in comparism to disk approximation test (D-test),. The performance of vitek-2 card was 100% specific and rapid for detection of inducible clindamycin resistance with other antimicrobial susceptibility results.[...] Read More.

Keywords: Automated system, constitutive macrolide-lincosamide-streptogramin B (MLS B) phenotype, inducible MLSB phenotype, methicillin resistance Staphylococcus aureus (MRSA), msrA gene (MS phenotype).

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Seasonal variation in the diversity and abundance of phytoplankton in a small African tropical reservoir

ADON Marie Paulette*, OUATTARA Allassane and GOURENE Germain

Abstract: Phytoplankton species composition and seasonal changes were investigated in the shallow reservoir of Adzopé. Taxonomic composition, diversity and abundance of phytoplankton were studied at 4 stations from May 2008 to February 2009, in relation to physical and chemical factors (temperature, conductivity, dissolved oxygen, transparency, pH, nutrients) and climatic factor (rainfall). The phytoplankton comprised 144 taxa, mainly Chlorophyta (29.45% of taxa), Euglenophyta (29.45%) Bacillariophyta (23.97%) and Cyanobacteria (10.27%). Phytoplankton density values were greatest during the transition season (short rainy season), lower during the dry seasons, and extremely lower during the long rainy season (mean value 356 105 cells/l, 44 105 cells/l and 35 105 cells/l respectively). Abundance was dominated by Anabaena constricta Szafer (Geitler) and Microcystis aeruginosa (Kütz.) Kütz. The diversity index varied between 2.1 bits/cells in long rainy season and 4.6 bits/cells in short dry season. The redundancy analysis (RDA) demonstrated a separation between the long rainy season and the other seasons due to the influence of the flood pulse.[...] Read More.

Keywords: Phytoplankton, shallow reservoir, species dominance, West Africa.

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Treatment guidelines and nosocomial infections: The South African experience

Essack, S. Y. and Connolly, C.

Abstract: Nationally-devised standard treatment guidelines (STGs) for nosocomial infections were evaluated in the context of antibiotic resistance within the public health care system in Kwazulu-Natal. A multi-centre surveillance study instituted in 3 hospitals at 3 progressive levels of health care (district, regional and tertiary) collected consecutive, non-repetitive isolates commonly implicated in nosocomial infections as cited by the STGs, viz., Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. Isolates were subjected to susceptibility testing against antibiotics recommended in the treatment guidelines as empirical treatment for nosocomial infections using the Kirby Bauer disc diffusion method advocated by the CLSI. Percentage susceptibility across (1) bacterial species, (2) antibiotics and (3) hospital levels was compared. Susceptibility to antibiotics recommended in the treatment guidelines and hence potentially successful empiric therapy ranged from 5 to 95% with multi-resistance evident in all isolates. Statistically significant differences in overall susceptibility were observed (1) across bacterial species, (2) within 2 of the 3 bacterial species for different antibiotics and; (3) across hospital levels for 2 antibiotics with p values[...] Read More.

Keywords: Treatment guidelines, nosocomial infections, antibiotic resistance.

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IN VIVO and IN VITRO protein profiling in ACACIA NILOTICA (L.): A nitrogen fixing tree

Full Length Research Paper

Abstract: Present investigation was the first attempt which deals with the IN VIVO and IN VITRO comparative study of protein level in ACACIA NILOTICA L., a nitrogen fixing tree. Protein was investigated in callus, seed, leaf and stem by means of SDS-PAGE. For obtaining the IN VITRO explant, the seeds were cultured on ½ MS medium under the IN VITRO condition. The cotyledonary nodal explants were taken from the IN VITRO seedlings and cultured in the MS medium supplemented in combination of 2, 4-D (0.4 mg/l) with BAP (0.25 mg/l). Though some differences were observed in the protein contents of IN VIVO and IN VITRO samples, the data proved that protein content in callus was higher than the seed following leaf and stem. In this study it was found that A. NILOTICA contained several protein bands of molecular weight 54.3, 44.1, 42.7, 40.1, 35.6, 31.2, 28.6, 24.7 and 19.5 kDa. These results indicate that the intensity of protein bands was high in IN VITRO sample compared to IN VIVO samples.[...] Read More.

Keywords: SDS-PAGE, in vitro, in vivo

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Cloning and expression of Corynebacterium diphtheriae toxin gene

Full Length Research Paper

Abstract: Diphtheria is an acute bacterial disease caused by oxygenic strains of Corynebacteria. Fatality rate of this disease, between 5 and 10%. In children under 5 years and adults, the fatality rate may be as much as 20%. Outbreaks, although very rare, still occur worldwide, even in developed nations. Diphtheria toxin (DT) is the major virulence factor for these organisms. The aim of this study was cloning and expression diphtheria toxin gene to produce recombinant protein and application in next investigations. The bacterial DNA was extracted and amplification of diphtheria toxin gene was carried out with specific primers. This gene was cloned in pTZ57R/T vector and sub cloned into pETDuet-1 expression vector then recombinant plasmid was transformed into BL21 of Escherichia coli strain and induced by IPTG. Diphtheria toxin gene was amplified successfully and cloned in pTZ57R. Recombinant plasmid was digested by restriction enzymes and released fragment (diphtheria toxin gene) sub cloned in pETDuet-1 expression vector and expressed protein was analysed in serological assay. In this study, the diphtheria toxin gene was cloned in pETDuet-1 expression vector and confirmed by sequencing and restriction analysis then recombinant plasmid was transformed in BL21 expression cell.[...] Read More.

Keywords: Diphteria, Corynebacterium diphtheriae toxin gene, recombinant protein, pETDuet-1.

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Molecular characteristic of Staphylococcus aureus isolates in a Chinese teaching hospital

Xiao-Ling Ma, Fei-Hu Chen*, Xin Zhou, Wen-Jiao Chang and Yuan-Yuan Dai

Abstract: The aim of this study is to investigate the genetic backgrounds of methicillin susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA) and heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) isolates isolated from clinical specimens of the patients with verified infections in a Chinese teaching hospital. Macro E test (MET) was used to detect hVISA and multilocus sequence typing (MLST) was used to determine the STs of the selected isolates. The genotypes of SCCmec were determined by multiplex polymerase chain reaction (PCR) in MRSA isolates. Panton-valentine leucocidin (PVL) genes were also detected by PCR. Among 273 S. aureus isolates, hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA), community-associated methicillin-resistant S. aureus (CA-MRSA), hospital-acquired methicillin susceptible Staphylococcus aureus (HA-MSSA) and community-associated methicillin susceptible Staphylococcus aureus (CA-MSSA) isolates accounted for 55.6, 1.5, 36.3, and 6.6%, respectively. Nine isolates were confirmed as hVISA by MET. Among 60 HA-MRSA isolates, ST239-MRSA-III was the most prevalent clone accounting for 51.7%, followed by ST5-MRSA-II clone. Fifty percentage and 22.2% of CA-MSSA isolates were found to be ST121 and ST88. ST239-MRSA-III was the predominant clone in hVISA isolates. However, no predominant ST type was found in HA-MSSA isolates. Of 9 PVL-positive strains, ST88 was the most prevalent ST (50.0%; 4/8), followed by ST121 (33.3%; 3/9), ST5 (4.5%; 1/22) and ST239 (2.6%; 1/39). In conclusion, ST239- III was the major pandemic clone in hVISA and HA-MRSA and spread in China. ST5- emerging rapidly in China had remained stable viability.[...] Read More.

Keywords: Staphylococcus aureus, heterogeneous vancomycin-intermediate Staphylococcus aureus, molecular characteristic.

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Characterization of pathogenic or non-pathogenic Enterococcus faecalis isolated from lambs from Xinjiang, a remove North-west province of China

ZHOU Xia*, WANG Dong and WANG Xiao-lan

Abstract: The majority of the 11 pathogenic Enterococcus faecalis from lambs developed encephalitis and 45 non-pathogenic E. faecalis from intestinal and respiratory microbiota of healthy lambs were belonged to Streptococcus serotype D. Haemolytic study revealed that 8 of 11 pathogenic stains had stable haemolyticus; 8/30 strains of intestinal normal microbita and 3 of 15 strains from respiratory system showed unstable haemolyticus. Of 11 pathogenics E. faecalis, 8 of 9 virulence factor genes were detected in all the strains; 5 of 11 expressed Esp, CylA, Asa1, Ace, efa, EF0591 and EF3314 simultaneously and 1 of 11 expressed GelE; Two of 11 did not express any of the 9 virulence factor genes. Among 30 strains isolated from the intestinal microbita, only one had 2 (GelE, EF3314) and one had 3 (GelE, EF3314 and Asa1) of the 9 virulence factor genes. The homology of these 3 common virulence gene fragments (GelE, EF3314 and Asa1) was more than 95% between E. faecalis from GenBank and intestinal microbita and 96% when comparing the E. faecalis isolated from intestinal microbita and from those of pathogenic strains. Antibiotic sensitivity study indicated that all of the 11 pathogenic strains were resistance to a variety of antibiotics in various degrees. In comparison, Only 2 strains from normal flora were resistance to individual antibiotics. In vivo challenge study showed that all of the 11 the pathogenic strains could lead to the death of mice, whereas none of the isolates from normal flora could cause the death of the experimental animals.[...] Read More.

Keywords: Biochemical characteristic, Enterococcus faecalis, lamb,virulence factor gene.

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Screening of Saccharomyces cerevisiae for high tolerance of ethanol concentration and temperature

Parviz Mehdikhani*, Mahmoud Rezazadeh Bari and Hrachya Hovsepyan

Abstract: The fermentation process of sugar feedstock materials at industrial scale requires the utilization of microorganisms capable of working at high ethanol concentration and high temperatures. The selection of Saccharomyces cerevisiae strains, able to ferment sugars obtained from different material at temperatures above 35°C with high ethanol yield, has become a necessity. Three yeast strains were irradiated with gamma ray and screened for their ability to grow and ferment molasses in a temperature range of 35-45°C. The yeasts were placed in a liquid medium, and irradiated at different doses (0.1, 1, 2, 3, 4, 5 and 10 KGy/h). Although all the isolated strains had growth (in agar plates) at 35 and 40°C, but just two strains showed growth at 42°C, and there was no growth at 45°C. Two pure yeast strains were isolated (PTCC5269 M3 and Areni M7). The efficiency of temperature and high concentrations of ethanol tolerant strains were more than double of ethanol production compared with using the initial strains of yeast. All resistant strains were tested on liquid medium of molasses, and nutrients with 30% (v/v) ethanol had significant difference (P>0.01) for growth intensity at same condition with initial strains.[...] Read More.

Keywords: Bioethanol, gamma radiation, Saccharomyces cerevisiae, thermotolerant.

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Primary resistance rates of Mycobacterium tuberculosis complex strains isolated from new tuberculosis cases

Servet Kayhan*, Alper Akgüne , Hikmet Tereci and Ümit Tutar

Abstract: The aim of the study was to evaluate the automated mycobacteria growth ındicator tube (MGIT) for drug susceptibility testing of Mycobacterium tuberculosis and to determine resistance patterns. We used BACTEC MGIT 960 System to determine the susceptibility of M. tuberculosis complex isolates to major anti tuberculous agents. Patients with single and first positive isolates were enrolled in the study. We have performed our drug susceptibility study between January 2005 and December 2010 for monitoring of drug resistance patterns in six years. A total of 1240 (77.16%) of the 1607 isolates were susceptible to all four of the antimycobacterial agents while 369 (22.96%) were found to be resistant to one or more of the drugs. The rate of isolates resistant to streptomycin (SM) was 6.84%, the other rates were 17.17% to isoniazid (INH), 5.28% to rifampicin (RIF) and 4.10% to ethambutol (ETM). Single drug resistance rates were found to be 12.13% for INH, 0.99% for RIF, 5.6% for SM, and 1.74% for ETM. The ratio of resistant isolates to all four drugs was 0.74% (n=12) and the prevalence of multidrug resistant isolates was 3.92% (n=63) . It was concluded that resistance to INH and RIF continues almost in a straight line in the present study. Monitoring of drug resistance patterns is essential for accurate drug regimen in management of tuberculosis.[...] Read More.

Keywords: Mycobacterium tuberculosis complex, primary resistance, ısoniazid, rifampicin.

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