None Of Isolates Research Articles

Prevalence and characterization of methicillin susceptible Staphylococcus aureus ST398 isolates from retail foods

In this study, we explored the prevalence of Staphylococcus aureus (S. aureus) ST398 in retail foods and then investigated for their virulence and antimicrobial resistance genetic background. Fourteen out of 5103 (0.27%) samples were positive for methicillin susceptible S. aureus (MSSA) ST398. Resistance was most frequently observed to penicillin (PEN) (100%), followed by trimethoprim (TMP), erythromycin (ERY) and ampicillin (AMP) (each 86.7%), clindamycin (CLD, 80.0%), and tetracycline (TET, 26.7%). All ST398 isolates were susceptible to amikacin, chloramphenicol, cefoxitin, gentamicin, oxacillin, and vancomycin. Two predominant resistance patterns including TMP-ERY-CLD-PEN-AMP (60.0%) and TMP-ERY-TET-CLD-PEN-AMP (20.0%) were identified. Isolates harbored blaZ (86.7%) gene, followed by tet(L) and linA/linA′ (each 46.7%), ermB and msrA (each 33.3%), aph(3′)-IIIa and dfrK (each 26.7%), tet(K) (20.0%), ant(4′)-Ia, ermA and emrC (each 13.3%) and cat::pC221 (6.7%). No isolate carried mecA, tet(M), tet(O), fexA, aac(6′)/aph(2″), cfr, ermT, msrB, cat::pC194, cat::pC223, catpIp-501, dfrD, dfrG and dfrS1 genes. For virulence genes, hld (73.3%), seb and sed (each 66.7%), hla (60.0%), lukPV (33.3%), sej (26.7%), lukED and seg (each 3.3%) were detected. None of isolates contained sea, sec, see, seh, sei, tst, eta, etb, sek-ser, seu, lukM, hlg, and hlgv genes. Four spa types were found, including t571 (6/15), t034 (4/15), t2876 (3/15) and t1250 (2/15). All strains were non-typeable for agr locus. Our findings indicated that MSSA ST398 isolates had a low prevalence rate in retail foods, and these isolates harbored multiple virulence and antimicrobial resistance genes, and exhibited multiple antimicrobial resistance. Further studies are required to elucidate the possible role of MSSA ST398 as a source of human infection.

Molecular Identification Virulence Genes Of Escherichia coli Isolated From Bovine Clinical Mastitis

The aims of this study were molecular identification some of virulence genes in Escherichia coli isolated from milk of bovines with clinical mastitis. (n = 60) E. coli isolates from acute clinical mastitis were examined for detect the presence of the genes encodingshigatoxin1 (stx1), intimin (eaeA), cytotoxicnecrotizingfactor 2 (cnf2), aerobactin (iucD) and P fimberiae (pap). The majors finding in the PCR assays were: 8 isolates (13.33%) had at least one virulence gene, None of isolates contained the genes for stx1, eaeA , the most common gene in the examined isolate was iucD which was positive in 6 isolates (10%). One isolate (1.66%) was positive for both iucD and pap genes and one isolate (1.66%) for cnf2 gene. In this study similar to previous investigations indicated that prevalence virulence genes in E. coli isolated of bovine mastitis is deferent. The results of this investigate similar to previous studies indicated none of the potential virulence genes or specific pathotype was observed in E. coli isolates from bovine clinical mastitis. DOI: http://dx.doi.org/10.3126/ijls.v8i2.10219 International Journal of Life Sciences Vol.8(2): 2014; 1-3

Single-Institute Surveillance of Blood-Stream Infections by Stenotrophomas Maltophilia Among Patients with Hematological Diseases

Abstract 4694 Introduction:Patients with hematological disease are often immunocompromised due to intensive chemotherapy, including hematopoietic stem cell transplantation (HSCT), and immunosuppressive therapy. Broad-spectrum anti-bacterial drugs were frequently given to those patients as an empiric therapy during a chemotherapy-induced myelosuppressive phase, which causes problematic emergence of drug-resistant strain and microbial substitution. Chemotherapy-induced disturbance of mucosa membrane barrier and skin barrier damage by central venous catheter (CVC) insertion gives pathogens an easy access to blood stream and a chance to develop blood-stream infections (BSIs).Stenotrophomonas maltophilia (S. maltophilia) has been reported to emerge as frequent offenders of immunocompromised patients, especially those with hematological diseases and prolonged neutropenia. S. maltophiliais known to possess a high-level intrinsic resistance to variety of anti-bacterial drugs, including higher-generation cephalosporins and carbapenemes. Objective:The aim of this study is to identify clinical characteristics of S. maltophilia BSIs such as drug sensitivity to properly treat immunocompromised patients with BSIs due to S. maltophilia. Materials and Methods:This retrospective cohort study included all patients who admitted at department of hematology in our institute and from whose blood culuture (BC) or CVC culture (CC) S. maltophilia was isolated during 8 years from September 2003. Samples with positivity within two weeks are counted as a single case. Results:Among 5478 samples of BC and 258 samples of CC submitted to the laboratory, pathogens were isolated from 645 samples (11.8%) of BC and 74 samples (29.8%) of CC. Among positive samples, S. maltophilia was isolated from 52 samples (8.1%) of BC and 9 samples (11.7%) of CC. S. maltophilia was the third most frequent pathogens, next to Staphylococcus epidermidis (23.6% in BC, 29.9% in CC) and Candida (23.6% in BC, 29.9% in CC). This samples occupied 75.8% of 69 BC samples and 52.9% of CC samples among all S. maltophilia positive samples within our institute during the same period. Among these 61 samples, 60 samples (40 cases) were during treatment for hematological malignancies (25 cases AML, 8 cases ALL, 5 cases malignant lymphoma, one case MDS and multiple myeloma). 21 cases were in CR and 6 cases were after allogenic HSCT. Treatment before fever onset was; 6 cases allogenic HSCT, 14 cases AML type, 8 cases ALL type, 3 cases CHOP-like and 3 cases oral agents.CVC was inserted to all patients except a MM patient. CVC culture was submitted in 18 cases of all BC cases and 7 cases (38.9%) were positive. Either BC or CC was positive in 31 cases and 3 cases, respectively. In 7 patients, repeated BC positivity was observed with interval from 22 days to one year 9 months (median 128 days).Most cases were given higher-generation cepharosporins and carbapenems before fever onset, 12 case and 6 cases respectively. Before obtaining samples, cephalosporins and carbapenems were given to 25 cases and 20 cases, respectively. Treatment against S. maltophilia was; 17 cases drawal of CVC, 17 cases minomycline (MINO), 16 cases ceftazidime (CAZ), 10 cases quinolones, 6 cases SMX/TMP (ST) and 6 cases borad-spectrum drugs. Senvitivities of isolated S. maltophilia were; ST 61/61, MINO 61/61, quinolone (levofloxacin:LVFX) 60/61, CAZ 44/61. Only 2 cases (2 patients) died due to S. maltophilia BSIs. Discussion:Our data also shows that patients with hematological malignancies, especially AML and ALL, or after allogenic HSCT, are highly immunocompromised and predisposed to S. maltophilia. Althought high mortality rates around 20% among cancer patients with S. maltophilia infection are reported recently, our series shows only 5% of mortality. Recent resistance to those antbiotics, including ST, was reported but sensitivity test showed our series held high sensitivity to MINO/CAZ/LVFX. Our lower mortality rate could be due to treatment with CAZ/ LVFX. It is reasonable that those patients were still in neutropenic phase and needed be treated aganist other bacterium simultaneously. Although ST was given in only limited cases, none of isolates were resistant to ST. It might be important to identify sensitivities of S. maltophilia isolated in own institutes and choose sensitive agents when S. maltophilia might be a presumable pathogen. Disclosures:No relevant conflicts of interest to declare.

Diversity of rhizobia associated with leguminous trees growing in South Korea

This study was carried out to examine the diversity of 34 isolates collected from 11 species of leguminous trees growing in South Korea. Phylogenetic relationships between these 34 isolates and reference strains of the Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium and Ensifer/Sinorhizobium were analysed by using 16S rRNA gene sequences. Twenty-one isolates were related to Mesorhizobium, four isolates to Rhizobium, and nine isolates to Bradyrhizobium. But none of isolates were related to Sinorhizobium/Ensifer and Azorhizobium. Robinia pseudoacacia and Amorpha fruticosa were nodulated by various genotypes of rhizobia out of them, most of the isolates belonged to the genus Mesorhizobium. The isolates from Lespedeza bicolar belonged to diverse genera of Mesorhizobium, Rhizobium, and Bradyrhizobium. The isolates from Maackia amurensis and Lespedeza maximowiezii var. tomentella were phylogenetically related to the genera of Bradyrhizobium. PCR-based RAPD method and phylogenetic analysis of the 16S rRNA results revealed a high phylogenetic diversity of rhizobial strains nodulating leguminous trees in South Korea. Also, the relationships between host and bacterial phylogenies showed that only Robinia pseudoacacia, and Wisteria floribunda have significantly unique branch length than expected by chance based on phylogenetic tree.

The use of PCR assay for quality testing of grain of winter wheat cultivated in organic, integrated, conventional system and monoculture in phytopathological aspect

The aim of experiments was to evaluate the occurrence of fungi on grain of winter wheat cv. Roma cultivated in four systems on the experimental fields owned by the Institute of Soil Science and Plant Cultivation. Among pathogenic species, fungi from genus <i>Fusarium</i> dominated. Their number was the lowest on grain harvested in organic system and the highest in integrated one. Saprotrophic species were represented mainly by <i>Alternaria alternata</i>, which occurred the most often in organic system. Determination of <i>F. avenaceum</i>, <i>F. culmorum</i> and <i>F. poae</i> with microscope was confirmed with a PCR assay. All isolates of <i>F. culmorum</i> and <i>F. poae</i> gave an amplification product of <i>Tri 5</i> gene coding the possibility of trichocene production, while none of isolates of <i>F. avenaceum</i>.

Evaluation of Biological Control Traits in Some Isolates of Fluorescent Pseudomonads and flavobacterium

Plant growth promoting rhizobacteria (PGPR) consisting a wide range of beneficial soil bacteria inhabiting rhizosphere of plant. Fluorescent pseudomondas are the most important plant growth promoting rhizosphere bacteria in different crop plants. In this research, twenty-five isolates of fluorescent pseudomonads isolated from forty soil samples of wheat rhizosphere and forty four isolates of Flavobacterium selected from the bacterial strains collection were employed. The ability of these isolates for production of chitinase, Salicylic acid, siderophore and hydrogen cyanide and antifungal activity against Rhizoctonia solani were determined. Results revealed that all the fluorescent pseudomonads isolates were able to produce siderophore on Chrome Azurol S (CAS) agar plates and siderophore is an important secondary metabolite in plant growth promotion and antifungal activity. In CAS agar method, the range of siderophore production was 0.34-1.21 halo diameter per colony diameter. None of these isolates were capable for chitinase production. Salicylic acid (SA) production by the isolates ranging from 0-10.91 g.ml-1 (average 2.48 g.ml-1). Bacterial ability for production of hydrogen cyanide had a great variation and based on this ability they were qualitatively classified in to high, relatively high, moderate and no production. Productions of studied metabolites were not detected in Flavobacterium isolates. Three isolates (PA24, PA1 and PA18) of fluorescent pseudomonads showed in vitro antifungal activity against Rhizoctonia solani. In contrast none of Flavobacterium isolates showed growth inhibition against the tested fungus. Results of this study showed that fluorescent pseudomonads which are native to soils of Iran had the potential to be used for promotion of plant growth and suppression of soil-borne plant pathogens. In contrast, Flavobacterium seem to be an inefficient rhizobacterium against plant pathogens because of incapability to production of some important secondary metabolites in plant growth promotion and antifungal activity. There is a need to study their effects on different agricultural crops.

IDENTIFICATION TARGETED ON toxR GENE AND DETECTION OF VIRULENT FACTOR ENCODING GENES ON Vibrio parahaemolyticus ISOLATED FROM RAW CHICKEN MEAT

A number of V. parahaemolyticus isolates has been isolated from raw chicken meat samples collected in Pasar raya Padang. Isolation was done using ChromagarTM Vibrio media. Identification of toxR gene was then done to these isolates. toxR is a very specific gene in V. parahaemolyticus species. Detection for the presence of genes encoding virulence factors, in this case were the gene encoding thermostable direct hemolysin (tdh) and TDH related hemolysin (trh) was performed on toxR positive V. parahaemolyticus isolates. Identification of toxR gene and detection of tdh and trh genes were done trough amplification using polymerase chain reaction PCR (method). The results showed that all of the tested V. parahaemolyticus isolates (22 isolates) had toxR gene, but none of isolates has gene encoding the production of virulence factors both tdh and trh.

Genetic Diversity of Fusarium proliferatum Populations from Maize, Onion, Rice and Sugarcane in Iran Based on Vegetative Compatibility Grouping

Fusarium proliferatum is the causal agent of stalk and root rot disease of maize, foot rot disease of rice, basal and root rot disease of onion and knife cut disease of sugarcane in Iran. In recent years, incidence and severity of these diseases have been increased in Iran. Fifty seven F. proliferatum single-spore isolates collected from diseased maize, rice, onion and sugarcane plants at different areas were used to study genetic diversity by determination of vegetative compatibility groups (VCGs). Chlorate-resistant nitrate non-utilizing (nit) mutants were recovered from selected isolates of F. proliferatum and used in complementation tests. All isolates in which both nit1 and NitM (or nit3) mutants were recovered, demonstrated self-compatibility. Vegetative compatibility tests by pairing nit mutants identified 30 VCGs among 57 isolates. Twenty-three isolates belonged to singlemember VCGs and the remaining 34 isolates, belonged to other seven multimember VCGs. Segregation of F. proliferatum isolates obtained from various area and host plants into different VCGs in Iran is reported for the first time. In this study, none of isolates obtained from rice complemented with any other isolates from onion and sugarcane and, non complementation occurred between onion and sugarcane isolates. Also, only one complementation occurred between one isolate of maize and one isolate of sugarcane and rice. Thus, a correlation between VCGs grouping and host preferences was founded. It is concluded that natural populations of F. proliferatum in Iran are probably genetically divergent and include isolates representing a potential risk for disease development.

Isolation and identification of Enterococcus faecium from seafoods: Antimicrobial resistance and production of bacteriocin-like substances

A collection of isolates from uncooked seafoods (molluscs, fish, and fish fillets) were identified as Enterococcus faecium species and studied in further detail. Isolates were clustered in well-defined genomic groups according to food origin after ERIC-PCR analysis. Four isolates (FR 1-2, FB 1-3-B, FB 3-1, FTA 1-2) decarboxylated lysine, ornithine, and tyrosine. Isolate FR 1-2 also decarboxylated histidine. Most isolates were sensitive to antibiotics of clinical use, but resistance was detected more frequently towards nitrofurantoin (50%), erythromycin (33.33%) or rifampicin (33.33%) to quinupristin/dalfopristin (12.5%). Resistance to β-lactams or vancomycin was not detected. The enterococcal antigen A was the presumed virulence trait detected most frequently. None of isolates carried haemolysin/cytolysin genes. Twelve isolates produced anti-listerial activity. Among them, seven isolates also produced bacteriocin-like inhibitory substances against other enterococci, and one isolate was also able to inhibit Staphylococcus aureus. Three isolates only were active against Listeria monocytogenes, and two only were active against enterococci. One bacteriocinogenic isolate carried the enterocin A structural gene, but genes corresponding to other enterocins (EntB, EntP, EntQ, Ent1071, EntL50A/EntL50B, and Ent31) were not detected. Bacteriocin-producing enterococci lacking undesirable traits (such as antibiotic resistance or biogenic amine production) or their produced bacteriocins could be potential candidates to aid in preservation of seafoods and other food products as well.

In vitro susceptibility of Plasmodium falciparum to monodesethylamodiaquine, quinine, mefloquine and halofantrine in Abidjan (Côte d'Ivoire).

Malaria is the primary cause of hospitalization in Côte d'Ivoire. Early treatment is one of the strategies to control this illness. However, the spread of resistance of Plasmodium falciparum to antimalarial drugs can seriously compromise this strategy. The aim of this study was to assess the in vitro susceptibility of P. falciparum to monodesethylamodiaquine and aminoalcohols in Abidjan (Côte d'Ivoire). We assessed the in vitro susceptibility of isolates collected from patients with uncomplicated malaria by using the WHO optical microtest technique. The proportions of resistance to monodesethylamodiaquine, méfloquine and halofantrine were 12.5%, 15.6% and 25.9%, respectively. For quinine, none of isolates showed evidence of in vitro resistance. However, two isolates (6.1%) had IC(50) values above 300 nM. The IC(50) of each drug was positively and significantly correlated to that of the other three drugs, and the correlation was higher between halofantrine and mefloquine. Our results showed that the in vitro chloroquine resistance reported in previous studies has been extended to other antimalarial drugs investigated in this study except for quinine. Therefore, it is necessary to implement a long-term monitoring system of antimalarial drug resistance.

The Evaluation of Usefulness of Potentially Probiotic <i>Lactobacillus</i> Strains as Components of Industrial Starter Cultures

The aim of the study was to investigate the possible use of nine Lactobacillus strains, previously isolated from infants faeces, as components of industrial starter cultures for yoghurt, soft white cheese and hard cheese production. There were no strong antagonistic interactions between isolates and commercial probiotics and yoghurt strains. None of isolates was able to grow at 3 o C, seven grew at 7 o C, all of them at 12 o C and 37 o C and only three at 45 o C. In the culture media containing 10.4% NaCl at pH 6.5 growth of four isolates was detected at 12 o

Evaluation of Imipenem/Imipenem+EDTA Disk Method for Detection of Metallo-β-Lactamase-producingKlebsiella pneumoniaeIsolated from Blood Cultures

The objective of this study was to evaluate the imipenem (IMP) and IMP+EDTA (IMP/IMP+EDTA) disk method for the detection of metallo-beta-lactamases (MBLs) in clinical isolates of Klebsiella pneumoniae with various MIC levels to IMP. Forty-one blood isolates of K. pneumoniae with MIC to IMP ranging from < or =0.5 to > or =16 microg/ml were examined. The MICs were determined by VITEK-2 (bioMerieux Vitek two, France). Disks of 10 microg IMP with and without the addition of 0.5 M EDTA were used for the IMP/IMP+EDTA disk method. The E-test (AB Biodisk, Solna, Sweden) for MBL detection was also used. All isolates were examined for the bla (VIM-1) gene by PCR and for clonality of VIM-1-producing isolates by pulsed-field gel electrophoresis (PFGE). All isolates with MIC values of IMP < or =0.5 microg/ml exhibited no differences in inhibition zone diameters (IZD) produced by IMP and IMP+EDTA disks, whereas the isolates with MICs > or =1 microg/ml showed an increase in IZD, ranging from 8 to 26 mm. All isolates with MIC values of > or =1 microg/ml were found positive for the bla (VIM-1) gene by PCR and for MBL production by the E-test, whereas none of isolates with MICs <0.5 microg/ml was found positive by any of the tests. DNA restriction fragments generated by PFGE of VIM-1-producing isolates were classified in four main types. The IMP/IMP+EDTA disk method is simple to perform, sensitive, and specific for detection of MBL-producing K. pneumoniae clinical isolates. K. pneumoniae isolates with MICs of IMP > or =1 microg/ml and/or IZD produced by IMP disk <19 mm should be tested for MBL production.

Epidemiology of antimicrobial resistance in enterococci of animal origin

We evaluated the epidemiology of antimicrobial resistance in enterococci from animal farms and the potential relation of resistance to antimicrobial use. Enterococci from faecal samples from 18 beef cattle, 18 dairy cattle, 18 swine, 13 chicken, and eight turkey farms were prospectively evaluated over a 6 year period from 1998 to 2003. We evaluated 1256 isolates of Enterococcus faecium and 656 isolates of Enterococcus faecalis. None was vancomycin resistant. Quinupristin/dalfopristin, gentamicin and ciprofloxacin resistance rates in E. faecium were 2%, 0% and 55% in beef cattle, 8%, 7% and 47% in dairy cattle, 21%, 1% and 47% in swine, 85%, 12% and 23% in chicken, and 52%, 13% and 24% in turkey isolates, respectively. For E. faecalis, gentamicin resistance rates were 0% in beef cattle, 24% in dairy cattle, 37% in swine, 32% in chicken, and 29% in turkey isolates, whereas 12%, 9%, 21%, 64% and none of isolates from beef, dairy, swine, chicken, and turkey farms, respectively, were resistant to ciprofloxacin. Quinupristin/dalfopristin resistance in E. faecium was more common on chicken and turkey farms using virginiamycin (P<0.0001 for both) compared with farms not using a streptogramin, gentamicin resistance was more common on dairy farms using gentamicin (P<0.0001) compared with farms not using this antibiotic, and ciprofloxacin resistance was more common on turkey and dairy farms using enrofloxacin compared with those with no enrofloxacin use (P=0.02 and P=0.04, respectively). For E. faecalis, gentamicin resistance was more frequently detected on dairy and swine farms using gentamicin (P<0.0001 and P=0.0052, respectively) and ciprofloxacin resistance was more common on beef farms using enrofloxacin (P<0.0001) compared with farms not using these antimicrobials. PFGE showed multiple strain types with some clones common between animals of the same animal species. This study shows the presence of a significant reservoir of antibiotic-resistant enterococci among farm animals. Resistance was more common on farms using antimicrobial agents.

Mutations in the rpoB gene of multidrug-resistant Mycobacterium tuberculosis isolates from China.

Mutations in the 81-bp rifampin resistance determining region (RRDR) and mutation V176F locating at the beginning of the ropB gene were analyzed by DNA sequencing of 86 Mycobacterium tuberculosis clinical isolates (72 resistant and 14 sensitive) from different parts of China. Sixty-five mutations of 22 distinct kinds, 21 point mutations, and 1 insertion were found in 65 of 72 resistant isolates. The most common mutations were in codons 531 (41%), 526 (40%), and 516 (4%). Mutations were not found in seven (10%) of the resistant isolates. Six new alleles within the RRDR, along with five novel mutations outside the RRDR, are reported. None of isolates contained the V176 mutation.