Synergistic effects of combinatorial chitosan and polyphenol biomolecules on enhanced antibacterial activity of biofunctionalaized silver nanoparticles

The present study reports the synergistic antibacterial activity of biosynthesized silver nanoparticles (AgNPs) with the aid of a combination of chitosan and seaweed-derived polyphenols as a green synthetic route. Under optimum synthesis conditions, the rapid color change from yellowish to dark brown and UV-visible absorption peak at 425 confirmed the initial formation of AgNPs. DLS, TEM, XRD, and EDX analyses revealed the spherical shape of pure biogenic AgNPs with a mean diameter size of 12 nm ± 1.5 nm, and a face-centered cubic crystal structure, respectively. FTIR and TGA results indicated the significant contribution of chitosan and polyphenol components into silver ions bioreduction and thermal stability of freshly formed AgNPs. Long-term colloidal stability of AgNPs was obtained after 6-month storage at room temperature. The bio-prepared AgNPs possessed a negative surface charge with a zeta potential value of - 27 mV. In contrast to naked chemical silver nanoparticles, the green Ag nanosamples demonstrated the distinct synergistic antibacterial in vitro toward all selected human pathogens presumably due to the presence of high content of biomolecules on their surface. The results show that synergy between chitosan and polyphenol results in the enhancement of bactericidal properties of biogenic AgNPs. We also highlighted the underlying mechanism involved in AgNPs formation based on nucleophile-electrophile interaction.

Clinical pharmacokinetics of flomoxef in prostate tissue and dosing considerations for prostatitis based on site-specific pharmacodynamic target attainment

Flomoxef is used to treat bacterial prostatitis; however, its prostatic pharmacokinetics have not been fully clarified. Flomoxef (500 or 1000 mg) was administered to patients with benign prostatic hypertrophy (n = 54). After a 0.5-h infusion, venous blood samples were drawn at time points of 0.5-5 h, and prostate tissue samples were collected at time points of 0.5-1.5 h during transurethral resection of the prostate. The drug concentrations in plasma and prostate tissue were analyzed pharmacokinetically and used for a stochastic simulation to predict the probability of attaining pharmacodynamic target in prostate tissue. Showing dose linearity in the prostatic pharmacokinetics, flomoxef rapidly penetrated into prostate tissue, with a prostate/plasma ratio of 0.48-0.50 (maximum drug concentration) and 0.42-0.55 (area under the drug concentration-time curve). Against the tested populations of Escherichia coli, Klebsiella and Proteus species isolates, 0.5-h infusion of 1000 mg three times daily achieved a ≥90% expected probability of attaining the bactericidal target (70% of the time above the minimum inhibitory concentration [MIC]) in prostate tissue. The site-specific pharmacodynamic-based breakpoint (the highest MIC at which the target-attainment probability in prostate tissue was >90%) values were 0.25 mg/L (MIC for 90th percentile of E. coli and Klebsiella species) for 500 mg four times daily and 0.5 mg/L (MIC₉₀ of Proteus species) for 1000 mg four times daily. These results help to fully characterize the prostatic pharmacokinetics of flomoxef, while also helping to rationalize and optimize the dosing regimens for prostatitis based on site-specific pharmacodynamic target attainment.

Analogues of Disulfides from Allium stipitatum Demonstrate Potent Anti-tubercular Activities through Drug Efflux Pump and Biofilm Inhibition

Disulfides from Allium stipitatum, commonly known as Persian shallot, were previously reported to possess antibacterial properties. Analogues of these compounds, produced by S-methylthiolation of appropriate thiols using S-methyl methanethiosulfonate, exhibited antimicrobial activity, with one compound inhibiting the growth of Mycobacterium tuberculosis at 17 µM (4 mg L-1) and other compounds inhibiting Escherichia coli and multi-drug-resistant (MDR) Staphylococcus aureus at concentrations ranging between 32-138 µM (8-32 mg L-1). These compounds also displayed moderate inhibitory effects on Klebsiella and Proteus species. Whole-cell phenotypic bioassays such as the spot-culture growth inhibition assay (SPOTi), drug efflux inhibition, biofilm inhibition and cytotoxicity assays were used to evaluate these compounds. Of particular note was their ability to inhibit mycobacterial drug efflux and biofilm formation, while maintaining a high selectivity towards M. tuberculosis H37Rv. These results suggest that methyl disulfides are novel scaffolds which could lead to the development of new drugs against tuberculosis (TB).

Urinary pathogenic bacterial profile, antibiogram of isolates and associated risk factors among pregnant women in Ambo town, Central Ethiopia: a cross-sectional study

Background

Urinary tract infection (UTI) is a well-known bacterial infection posing serious health problem in pregnant women. A study was conducted in pregnant women with the objectives of estimating prevalence of UTI, determining antibiogram of the bacterial isolates and assessment of the potential risk factors associated with UTI.

Methods

A cross-sectional study design was used to collect 300 mid-stream urine samples from pregnant women from March 2016 to December, 2016. Samples were inoculated into Cysteine Lactose Electrolyte Deficient medium (CLED). Colonies from CLED were subcultured onto MacConkey and Blood agar plates. A standard agar disc diffusion method was used to determine antimicrobial susceptibility. Chi-square (X2) test & logistic regression were used to show associations between UTI and explanatory variables & identify the predictors of UTI, respectively.

Results

The age of pregnant women enrolled in this study ranges from 16 to 46 years (mean ± standard deviation = 25 ± 4.7 years).The overall prevalence of UTI in pregnant women was 18.7% (95% confidence interval [CI]: 14.4-23.54%).The prevalence of symptomatic and asymptomatic UTI was 20.4% (95% CI: 13.09-29.46%) and 17.8% (95% CI: 12.70-23.83%) respectively. The predominant bacteria identified were E. coli (46.4%), S. aureus (14.3%), coagulase negative Staphylococci [CoNS] (14.3%) and Proteus species (10.6%). Majority of Gram-negative bacteria isolates were resistant to ampicillin (70%), ceftriaxon (66%), gentamicin (68%) and nitrofurantoin (64%) while 75-100% of the Gram positive isolates were resistance to ampicillin. Multiple drug resistance was observed in all of the isolates. Multivariable logistic regression revealed that the odds of acquiring UTI was 4.78 times higher in pregnant women earning monthly income of ≤500 Ethiopian Birr (21.18 USD) as compared to those earning monthly income >2001 Ethiopian Birr [84.79 USD] (P = 0.046). Similarly, the risk of UTI was higher in those who eat raw meat (OR = 2.04, 95% CI: 1.09, 3.83, P = 0.026) and had previous UTI history (OR = 2.29, 95% CI = 1.15-4.56, P = 0.019) as compared to those who eat cooked meat and had no previous history of UTI.

Conclusions

The prevalence & antimicrobial resistance of uropathogens was high. Health education, continuous surveillance of UTI and their antimicrobial resistance pattern are essential to reduce the consequence of symptomatic and asymptomatic bacteriuria and multi-drug resistant bacteria in pregnant women.

Bacterial resistance in urinary tract infections in patients with diabetes matched with patients without diabetes

BACKGROUND

With bacterial resistances having increased, patients with diabetes who are at higher risk of urinary tract infection (UTI) need to be studied. The study aim was to compare bacterial resistances to ofloxacin, cefixim, co-trimoxazole, nitrofurantoin and fosfomycin in UTI between patients with and without diabetes.

METHODS

A cross-sectional study was conducted in ambulatory laboratories, including patients over 18 coming for urinalyses. Patients with diabetes were matched with two patients without diabetes based on risk factors for UTI using a propensity score.

RESULTS

Among 1119 patients with UTI, 124 patients with diabetes were matched with 246 patients without diabetes. In patients with diabetes, the bacteria identified were: Escherichia coli (71%), Klebsiella (6%), Staphylococcus (5%), Enterococcus (4%), Proteus (2%) and Pseudomonas (1%); these findings were similar to those found in patients without diabetes. Resistances to ofloxacin and cefixim regardless of the bacteria were increased in patients with diabetes after matching on age, sex and history of UTI (respectively: OR=2.09; p=0.04 and OR=3.67; p=0.05). Regarding E. coli resistance, there was no difference whatever the antibiotic.

CONCLUSION

The increased ofloxacin and cefixim resistance in patients with diabetes should be considered when prescribing probabilistic antibiotics, and could lead to changes in first-line treatments in UTI.

[ANTIMICROBIAL ACTION OF NOCARDIA VACCINII IMV B-7405 SURFACTANTS]

AIM

To study the effect of Nocardia vaccinii IMV B-7405 surfactants on some bacteria (including pathogens of genera Proteus, Staphylococcus, Enterobacter), yeast of Candida species and fungi (Aspergillus niger R-3, Fusarium culmorum T-7).

METHODS

The antimi- crobial properties of surfactant were determined in suspension culture by Koch method and also by index of the minimum inhibitory concentration. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1).

RESULTS

It is shown that the antimicrobial properties of N. vaccinii IMV B-7405 surfactant depended on the degree of purification (supernatant, solution of surfactant), concentration and exposure. Survival of Escherichia coli IEM-1 and Bacillus subtilis BT-2 (both vegetative cells and spores) after treatment for 1-2 hours with surfactants solution and the supernatant (the surfactant concentration 21 µg/ml) was 3-28%. Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants on studied bacteria, yeast and micromycetes were 11.5-85.0; 11.5-22.5 and 165.0-325.0 µ/ml respectively.

CONCLUSIONS

Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants are comparable to those of the known microbial surfactants. The possibility of using the supernatant of culture liquid as an effective antimicrobial agent noticeably simplifies and reduces the cost of the technology of its obtaining.

In vitro bactericidal activity of cefepime and cefpirome against clinical isolates at Karachi

Antibiotics not only support to alleviate the infections but also facilitate to avert the multiplication of microbes. Due to the irrational use of antibiotics, the resistance of antibiotics has been augmented which results may increase in morbidity and mortality with the span of time. World renowned regulatory bodies like Food and Drug Administration (FDA), Center of Disease Control and Prevention (CDC), and World Health Organization (WHO) vigorously advocate the surveillance of the resistance of antibiotics. During the present study by Kirby-Bauer disk diffusion method 141 clinical isolates of Staphylococcus aureus (n=47, 33.34%), Escherichia coli (n=54, 38.3%), Proteus species (n=26, 18.4%), and Klebsiella pneumoniae (n=14, 9.92%) are evaluated against cefepime and cefpirome which comes of fourth generation cephalosporin. It has been found that cefpirome has better bactericidal activity than cefepime against E. coli and K. pneumoniae while cefepime has been possessed better antibacterial activity against S. aureus and Proteus species which were isolated from respiratory tract infections, blood stream infection, intra-abdominal and urinary tract infections, and skin and soft tissue infections. K. pneumoniae, E. coli, Proteus species, and S. aureus were 34.8%, 26.3%, 11.3%, and 37.7% resistance against cefepime respectively. S. aureus, E. coli, K. pneumoniae, Proteus species has shown 41.4%, 21.7%, 17.6%, and 8.9% resistance against cefpirome correspondingly.

[THE USE OF PROBIOTICS IN PATIENTS WITH RHEUMATOID ARTHRITIS]

The results of biological research of colon microbiota of patients with rheumatoid arthritis (RA) is in article presented. The signs of III degree dysbiosis, by reducing the concentration of Bacteroides spp., Bifidobacterium spp., Lactobacillus spp. populations, typical strain E. coli. But over growth of populations Klebsiella spp., Proteus spp., Staphylococcus spp., atypical forms of E. coli, Candida spp. The scheme for the correction of the colon microflora of patients with (RA) by was proposed bifiform. Increasing of populations concentration of Bifidobacterium spp., Bacteroides spp., Lactobacillus spp., typical E. coli, Enterococcus spp. and selective decontamination of Enterococcus (Hly+), Klebsiella spp., Proteus spp., Staphylococcus spp., lactosonegative and E.coli (Hly+) confirmed after using of this eubiotics.

Spectroscopic analysis, DNA binding and antimicrobial activities of metal complexes with phendione and its derivative

A novel ligand (E)-2-styryl-1H-imidazo [4, 5-f] [1, 10] phenanthroline(L) has been synthesized from 1,10-phenanthroline-5,6-dione. Its transition metal complexes, [FeLCl4][L-H] and [CuL2](NO3)2 have also been synthesized. Besides, three mixed ligand lanthanide metal complexes of Phendione and β-diketones have been synthesized, namely [Eu(TFN)3(Phendione)] (TFN = 4,4,4-trifluoro-1(2-napthyl)-1,3-butanedione), [Eu(HFT)3(Phendione)] (HFT = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione), [Yb(HFA)3(Phendione)] (hfa = hexafluoroacetylacetonate). The synthesized ligands and metal complexes have been characterized by FTIR, UV-Visible spectroscopy and PL spectra. DNA binding activities of the complexes and the ligands have been studied by DNA gel electrophoresis. DNA binding studies showed that Fe complex of the synthesized ligand is more potent DNA binding and damaging agent compare to others under study. The synthesized compounds were also screened for their antimicrobial activities by disc diffusion method against three microbes, namely Escherichia coli, Staphylococcus aureus, Proteus penneri. The lanthanide complexes of phendione showed great antibacterial activities.

Efficacy of some colloidal silver preparations and silver salts against Proteus bacteria, one possible cause of rheumatoid arthritis

There has been increased interest in the role of anti-Proteus antibodies in the aetiology of rheumatoid arthritis (RA) and whether chemotherapeutic agents active against Proteus species might reduce the risk and/or exacerbations of RA. We examined the in vitro antibacterial effects of ten different silver preparations which were either ionic silver [Ag(I)] solutions or nanoparticulate silver (NPS) (Ag(0)) suspensions against ATCC and two wild (clinical) strains of Proteus. The data establish the low minimum inhibitory concentration and minimum bactericidal concentration of all the silver formulations tested against these four Proteus strains. In a pilot study, a potent NPS preparation ex vivo showed long-lasting anti-Proteus activity in a normal human volunteer.

[Oflomelid ointment: activity against hospital microbial strains]

Ofloxacin susceptibility was tested with the use of 100 hospital isolates by the disk diffusion method vs. the activity of Oflomelid ointment tested by the cavity method. It was shown that the hospital isolates of all the species were susceptible to the Oflomelid ointment, while susceptibility to ofloxacin was preserved in S. epidermidis, the susceptibility of Acinetobacter spp., E. coli, Proteus spp. being intermediate. Such a difference in the susceptibility of the isolates was evidently due to the properties of polyethylene glycols in the ointment composition.

Resistance pattern of clinical isolates involved in surgical site infections

Wound infections due to the incursion of microbes need to be averted or to heal the wounds by antibiotics. Antibiotics are not only aid in cure of infections but also help to prevent the flourishing and production of one or more species of microorganism, resultant in purulent discharge. This current study was carried out to evaluate the resistance pattern of clinical isolates from surgical site infections by the Kirby Bauer disc diffusion method. A total of 257 clinical isolates were collected from different hospitals in Karachi and evaluated by using fifteen antibiotics belonging to different groups. Staphylococcus aureus (n=87), Escherichia coli (n=76), Pseudomonas aeruginosa (n=56), Proteus (n=21) and Klebsiella (n=17) species are the most common clinical isolates of surgical site infections. Among the semi-synthetic penicillins, ampicillin was found to be resistant to nearly all clinical isolates but amoxicillin was moderately sensitive to S. aureus. Combinations of semi-synthetic penicillins are more sensitive than the penicillin alone. Co-amoxiclave exhibits superior sensitivity to all the surgical infection isolates except Pseudomonas aeruginosa which showed 68.75% resistance. Pseudomonas aeruginosa was highly resistant to cephalosporin except ceftraixone which showed 21.88% resistance. S. aureus was slightly responsive to cefazolin, cephradine, cefaclor, ceftizoxime, cefuroxime and ceftriaxone. E. coli, Gram-negative clinical isolate was showed 25% and 31.25% resistance to ceftriaxone and cefuroxime. In the Klebsiella species, 71.42% and 64.29% resistance to cefazolin and cefuroxime respectively, was observed. Aminoglycosides such as gentamycin and tobramycin were found to be more susceptible to all the clinical isolates. Quinolones like ofloxacin and enoxacin were showed good sensitivity to nearly all the clinical isolates.On the basis of the present study, it is recommended to adopt a rational use of antibiotics in prophylaxis and the utilization of a coordinated scheme of surgical wound inspections.

Surface plasmon resonance optical sensor and antibacterial activities of biosynthesized silver nanoparticles

Silver nanoparticles were prepared using aqueous fruit extract of Ananas comosus as reducing agent. These silver nanoparticles showed surface plasmon peak at 439 nm. They were monodispersed and spherical in shape with an average particle size of 10 nm. The crystallinity of these nanoparticles was evident from clear lattice fringes in the HRTEM images and bright circular spots in the SAED pattern. The antibacterial activities of prepared nanoparticles were found to be size-dependent, the smaller nanoparticles showing more bactericidal effect. Aqueous Zn(2+) and Cu(4+) selectivity and sensitivity study of this green synthesized nanoparticle was performed by optical sensor based surface plasmon resonance (SPR) at room temperature.

Comparative evaluations on bio-treatment of hexavalent chromate by resting cells of Pseudochrobactrum sp. and Proteus sp. in wastewater

Two marine bacterial strains, B5 and H24, were isolated from long-term Cr(VI) contaminated seawater and identified as Pseudochrobactrum and Proteus, respectively, based on 16S rRNA gene sequence analyses. Both strains were examined for their tolerance to Cr(VI) and other metal salts and their abilities to reduce Cr(VI) to trivalent chromium [Cr(III)]. Growing cells of Pseudochrobactrum sp. B5 and Proteus sp. H24 could tolerate Cr(VI) at a concentration of 2000 and 1500 mg/l and completely reduce 1000 mg/l Cr(VI) in LB medium within 96 and 144 h, respectively. Resting cells of the two strains were able to reduce 200mg/l Cr(VI) in Tris-HCl buffer within 16 and 24h, respectively. Furthermore, resting cells of both strains were able to reduce Cr(VI) in industrial wastewaters three times consecutively. Overall, this study provides evidence of the potential for application of chromate-reducing bacteria to direct Cr(VI) decontamination of industrial effluents.

Anti-Proteus activity of some South African medicinal plants: their potential for the prevention of rheumatoid arthritis

A wide variety of herbal remedies are used in traditional African medicine to treat rheumatoid arthritis (RA) and inflammation. Thirty-four extracts from 13 South African plant species with a history of ethnobotanical usage in the treatment of inflammation were investigated for their ability to control two microbial triggers for RA (Proteus mirabilis and Proteus vulgaris). Twenty-nine of the extracts (85.3 %) inhibited the growth of P. mirabilis and 23 of them tested (67.7 %) inhibited the growth of P. vulgaris. Methanol and water extracts of Carpobrotus edulis, Lippia javanica, Pelargonium viridflorum, Ptaeroxylon obliquum, Syzygium cordatum leaf and bark, Terminalia pruinoides, Terminalia sericea, Warburgia salutaris bark and an aqueous extract of W. salutaris leaf were effective Proteus inhibitors, with MIC values <2,000 μg/ml. The most potent extracts were examined by Reverse phase high performance liquid chromatography and UV-Vis spectroscopy for the presence of resveratrol. Only extracts from T. pruinoides and T. sericea contained resveratrol, indicating that it was not responsible for the anti-Proteus properties reported here. All extracts with Proteus inhibitory activity were also either non-toxic, or of low toxicity in the Artemia nauplii bioassay. The low toxicity of these extracts and their inhibitory bioactivity against Proteus spp. indicate their potential for blocking the onset of rheumatoid arthritis.

The co-selection of fluoroquinolone resistance genes in the gut flora of Vietnamese children

Antimicrobial consumption is one of the major contributing factors facilitating the development and maintenance of bacteria exhibiting antimicrobial resistance. Plasmid-mediated quinolone resistance (PMQR) genes, such as the qnr family, can be horizontally transferred and contribute to reduced susceptibility to fluoroquinolones. We performed an observational study, investigating the copy number of PMQR after antimicrobial therapy. We enrolled 300 children resident in Ho Chi Minh City receiving antimicrobial therapy for acute respiratory tract infections (ARIs). Rectal swabs were taken on enrollment and seven days subsequently, counts for Enterobacteriaceae were performed and qnrA, qnrB and qnrS were quantified by using real-time PCR on metagenomic stool DNA. On enrollment, we found no association between age, gender or location of the participants and the prevalence of qnrA, qnrB or qnrS. Yet, all three loci demonstrated a proportional increase in the number of samples testing positive between day 0 and day 7. Furthermore, qnrB demonstrated a significant increase in copy number between paired samples (p<0.001; Wilcoxon rank-sum), associated with non-fluoroquinolone combination antimicrobial therapy. To our knowledge, this is the first study describing an association between the use of non-fluoroquinolone antimicrobials and the increasing relative prevalence and quantity of qnr genes. Our work outlines a potential mechanism for the selection and maintenance of PMQR genes and predicts a strong effect of co-selection of these resistance determinants through the use of unrelated and potentially unnecessary antimicrobial regimes.

Bacteriological agents of chronic discharging ears and their antibiotic sensitivity pattern in Ido - Ekiti, Nigeria

AIMS AND OBJECTIVES

To identify bacterial agents of chronic discharging ear and determine their antibiotic sensitivities pattern in Ido - Ekiti, Nigeria.

PATIENTS AND METHODS

Swab specimens of each chronically (>8 weeks) discharging ears of patients with chronic suppurative otitis media (CSOM) presenting to the Ear, Nose and Throat (ENT) clinic of the Federal Medical Centre, Ido Ekiti were bacteriologically cultured aerobically and the antibiotic sensitivity pattern of the recovered organisms determined by the modified Kirby-Bauer disc-diffusion method over a three year period starting from January 2005.

RESULTS

Seventy eight patients with CSOM whose age ranged between 3 months and 85 years were seen during the study period with 73.1% of them having unilateral disease and majority were children < 15 years (71.8%). Out of 99 ear swabs that were examined, 87.9% were culture positive with 90.8% yielding a single isolate. Coliforms (34.7%) were the most frequent isolated group of organisms. Other isolates included Staphylococcus aureus (26.3%), Proteus spp (24.2%), Pseudomonas spp (9.5%) and Klebsiella spp (5.3%). Sparfloxacin and ciprofloxacin showed highest activity on all the isolates unlike cefuroxime and ceftiaxone to which all isolates were resistant.

CONCLUSION

Chronic discharging ear is caused by bacteria agents most sensitive to quinolones but resistant to cefuroxime and ceftiaxone. Treatment of patients with CSOM in Ido-Ekiti with the quinolones is recommended except where contraindicated.

[Clinical and molecular characterization of ESBL-producing enterobacteria isolated from bacteremia in a university hospital]

INTRODUCTION

Extended-spectrum-β-lactamases (ESBL) are plasmid-encoded enzymes that confer resistance to multiple antimicrobials. ESBL-producing enterobacteria that cause bacteremia limit therapeutic options and increase mortality.

OBJECTIVE

To perform a clinical and molecular description of bacteremia caused by ESBL-producing enterobacteria.

METHOD

We retrospectively studied the cases of bacteremia due to ESBL-producing Escherichia coli, Klebsiella pneumoniae and Proteus spp in adults admitted to a university hospital during the years 2004-2007. We reviewed the clinical records and antimicrobial susceptibility patterns. Molecular typing was performed by polymerase chain reaction and study of clonality by pulsed-field electrophoresis.

RESULTS

We found a prevalence of 9.8% ESBL in enterobacteria causing bacteremia. Decreased susceptibility to quinolones and aminoglycosides was observed, without resistance to carbapenems. The predominant ESBL types were CTX-M (96%), TEM (62%) and GES (28%). 79% of the strains presented more than one type of ESBL. Clinical analysis revealed high prevalence of risk factors, previous use of antimicrobials and of invasive devices. There was no significant clonality.

CONCLUSION

The presence of ESBLs in bloodstream infections is a clinical problem that must be considered when choosing empiric therapy.

Antimicrobial activity of erythromycin and clarithromycin against clinical isolates of Escherichia coli, Staphylococcus aureus, Klebsiella and Proteus by disc diffusion method

Fifty clinical isolates comprising of Escherichia coli, Staphylococcus aureus, Klebsiella and Proteus were collected from different local pathological laboratories and their resistant pattern against two well known macrolides; erythromycin and clarithromycin were studied using disc diffusion method. Klebsiella (41.67% against erythromycin and 58.34% against clarithromycin) and Proteus (66.67% against erythromycin and clarithromycin) species were found to be more resistant against the studied macrolides as compared to the rest of organisms. In case of Staphylococcus aureus and Escherichia.coli, resistant found were 27.78% and 23.54% against erythromycin and 22.23% and 35.30% against clarithromycin respectively. It is concluded from these figures that microbial resistance against these macrolides are increasing in our population which is alarming and therefore it is recommended to physicians to prescribe these antibiotics unless no other substitute is available in clinical practices.

Detection and PFGE analysis of ESBL-producing isolates of Proteus species isolated from patients at Tehran hospitals

BACKGROUND

The production of extended-spectrum β-lactamases (ESBLs), in particular TEM and CTX-M type, by the strains of Proteus spp. is a contributing factor to the emergence of bacterial drug resistance. The aim of this study was to screen and determine of ESBLs genes among strains of Proteus spp. at Tehran hospitals.

MATERIAL/METHODS

A total of 100 clinical isolates of Proteus species and 1 isolate of Morganella morganii were collected from hospitals in Tehran. Susceptibility of these isolates to various antibiotics was tested by disk diffusion method. Microbroth dilution assay was then used to determine the minimum inhibitory concentration (MIC) of ceftazidime. The phenotypic confirmatory test (PCT) was used for detection of ESBLs. Isolates showing MIC ≥4 µg/ml for ceftazidime were screened for detection of ESBLs genes by PCR. The genomic DNA from ESBL-producing isolates was extracted and analyzed by PFGE.

RESULTS

During the study, 11.8% of the isolates were positive for ESBLs genes. The MICs of ceftazidime-resistant isolates were in the range of 4 to 8 µg/ml. The Frequencies of different genes encoding the ESBLs were as follows: blaCTX-M (n=13), blaTEM (n=10), blaVEB (n=7), blaSHV (n=1), and blaPER (n=0). Analysis of 12 ESBL-producing isolates by PFGE produced 5 distinct clusters designated as I-V.

CONCLUSIONS

The Detection of ESBL-producing isolates of Proteus spp. with similar PFGE pattern is alarming and suggests the clonal outbreaks with these strains at Tehran hospitals is likely, necessitating control over prescription of new generation cephalosporins.

In-vitro activity of three brands of ceftriaxone against different clinical isolates

INTRODUCTION

Ceftriaxone is an extended spectrum cephalosporin that has been used for decades for combating infections caused by wide array of pathogens and prescription of antibiotic is in favor of specific brands without realizing the potency of the brand. The in-vitro activity of three brands of ceftriaxone and various antibiotics against clinical isolates is studied.

METHODS

This comparative study was carried in Kathmandu Medical College Teaching Hospital (KMCTH), Basic Science Complex, Duwakot, Bhaktapur in 2009. Thirteen clinical isolates isolated from the specimens processed in the Microbiology Laboratory at KMCTH were used. Minimum inhibitory concentration (MIC) of three brands of ceftriaxone (A, B, and C) was determined by agar dilution and antibiotic resistance patterns were deduced by disc diffusion test.

RESULTS

MIC for three brands of ceftriaxone ranged from < 0.25 to > 256 mg/L. The MIC for brands A and C of ceftriaxone were consistent for all isolates while for brand B, MIC was higher by at least two fold suggesting this brand had less in-vitro activity against isolates tested. All isolates were multi-drug resistant. Ceftriaxone resistant isolates (n = 6) were simultaneously resistant to various antibiotics tested. Imipenem and amino glycosides were sensitive to the isolates studied.

CONCLUSIONS

Different brands of ceftriaxone are available in Nepal and imprudent use of less potent antibiotics should be controlled to stop the emergence and spread of multi-drug resistant pathogens and to prevent undue economic burden to the patient and the country.

Antimicrobial resistance patterns of Staphylococcus aureus and Proteus spp. isolated from otitis media at Bahir Dar Regional Laboratory, North West Ethiopia

OBJECTIVES

Otitis media is a major health problem of children in low income countries like Ethiopia. Thus, this study was aimed at determining the predominant bacterial isolates from discharging ear and their antimicrobial susceptibility patterns.

METHODS

A retrospective study was conducted on records of 777 patients for whom ear discharge swabs were processed for culture and susceptibility tests at Bahir Dar Regional Health Research Laboratory from September 2000 to December 2008.

RESULTS

From 777 ear discharges, male patients with discharging ear constituted 459 (59%) with overall male to female ratio of 1.4:1. Their age was ranging from 2 months to 85 years. Six hundred eight (78.3%) ear discharge swabs were culture positive for bacteria. The isolation rates of S. aureus and Proteus spp. were 260 (42.7%) and 227 (37.3%) respectively. Proteus spp. was the predominant isolate in children whereas S aureus in adults (p = 0.0001). S. aureus and Proteus spp. exhibited high rates of resistance to most antimicrobial agents tested. However, they showed lower resistance rate to gentamicin and norfloxacillin.

CONCLUSION

Otitis media was a common health problem of all age groups. S. aureus and Proteus spp. were the predominant pathogens of discharging ear. Gentamicin and norfloxacillin would be the drug of choice for the empirical therapy of otitis media.

Effective strategies for prevention and control of Gram-negative infections

Infections caused by Gram-negative bacteria such as Pseudomonas, Klebsiella, Proteus and Acinetobacter have been a major problem in healthcare settings for many years. Overlooked in government targets and unknown to patients, these infections present considerable challenges for effective infection prevention and control. Key strategies for prevention and control focus on contact precautions, the management of invasive devices and maintaining a clean, dry environment to prevent the build-up of environmental reservoirs and cross-infection.

Hospital and community isolates of uropathogens at a tertiary hospital in South Africa

AIM

To investigate the profile of common uropathogens isolated from urine specimens submitted to the diagnostic microbiology laboratory at a tertiary teaching hospital and assess their antimicrobial susceptibility patterns to commonly used antimicrobial agents.

METHODS

We conducted a retrospective analysis of laboratory reports for all urine specimens submitted for investigations over a 1-year period. Isolates were tested by means of the Kirby-Bauer disc diffusion method for susceptibility to amoxicillin, ciprofloxacin, gentamicin, co-trimoxazole and nitrofurantoin, and for extended-spectrum beta-lactamase (ESBL) production.

RESULTS

Out of the total specimens (N=2,203) received over the 1-year study period, 51.1% (1,126) of the urine samples were culture-positive, the majority (65.4%) having come from females. The most common isolate was Escherichia coli (39.0%) followed by Klebsiella species (20.8%) and Enterococcus faecalis (8.2%). The Gram-negative isolates displayed a very high level of resistance to amoxicillin (range 43 - 100%) and co-trimoxazole (range 29 - 90%), whereas resistance to gentamicin (range 0 - 50%) and ciprofloxacin (range 0 - 33%) was lower. E. coli isolates were susceptible to nitrofurantoin (94%), and ESBL production was significantly higher (p=0.01) in the hospital isolates, compared with those from the community referral sites.

CONCLUSIONS

The culture-positive rate for uropathogens was high, with a greater incidence among females. E. coli was the most common aetiological agent identified, and remained susceptible to nitrofurantoin. Resistance levels to amoxicillin and co-trimoxazole were very high for all Gram-negative isolates, and it is recommended that these antibiotics should not be used for the empiric treatment of urinary tract infections.

Incidence of multiple antibiotic resistant Gram-negative bacteria isolated from surface and underground water sources in south western region of Nigeria

In most rural and urban settlements, particularly in Nigeria, wells, spring, streams or rivers and lakes serves as major sources of water supply for drinking and other domestic purposes. Unfortunately, many of the available water sources are not potable without some form of treatment which is seldom available in most settings. The use of untreated surface water sources for drinking and for domestic purposes remains a major threat to public health as these could serve as reservoirs the for transfer of antibiotic resistant pathogens. The incidence of resistant bacteria isolated from surface and underground water in six rural settlements in Ekiti State Nigeria was thus investigated. Gram-negative bacteria were isolated from wells, streams and boreholes in six rural settlements in Ekiti State Nigeria between January and April, 2006 and the prevalence of organisms exhibiting multiple antibiotic resistance to tetracycline, amoxicillin, cotrimoxazole, nitofurantoin, gentamicin, nalidixic acid and ofloxacin was observed. Gram-negative bacterial isolates comprised Escherichia coli (22.7%), Enterobacter aerogenes (2.5%), Salmonella spp. (13.3%), Shigella spp. (19.3%), Proteus spp. (18.5%), Klebsiella spp. (19.3%) and Pseudomonas aeruginosa (4.2%). Over 10% of the bacteria were resistant to four or more antibiotic. Antibiotic resistance was highest in members of the genera Enterobacter, Pseudomonas, and Proteus. Given the prevalence of appalling sanitary facilities and inappropriate public antibiotic use, the possibility of antibiotic resistance selection, faecal dissemination and subsequent contamination of local water sources available for rural residents of the developing world is highlighted. The implication for clinical practice of infections caused by antibiotic resistant strains especially among immunodeficient individuals is also discussed.

Antimicrobial resistance and prevalence of canine uropathogens at the Western College of Veterinary Medicine Veterinary Teaching Hospital, 2002-2007

Between January 2002 and June 2007, uropathogens were isolated from 473 of 1557 canine urine samples submitted to Prairie Diagnostic Services from the Western College of Veterinary Medicine Veterinary Teaching Hospital. Culture and susceptibility results were analyzed, retrospectively, to estimate the prevalence of common bacterial uropathogens in dogs with urinary tract infections and to identify changes in antimicrobial resistance. The most common pathogens identified were Escherichia coli, Staphylococcus intermedius, Enterococcus spp., and Proteus spp. Antimicrobial resistance increased during the study period, particularly among recurrent E. coli isolates. Using the formula to help select rational antimicrobial therapy (FRAT), bacterial isolates were most likely to be susceptible to gentamicin, fluoroquinolones, amoxicillin-clavulanic acid, and groups 4 and 5 (third generation) cephalosporins.

Antibacterial activity of halogenated sesquiterpenes from Malaysian Laurencia spp

During our studies on Malaysian Laurencia species, brominated metabolites, tiomanene, acetylmajapolene B, and acetylmajapolene A were isolated from an unrecorded species collected at Pulau Tioman, Pahang along with known majapolene B and majapolene A. Acetylmajapolene A was a mixture of diastereomers as in the case of majapolene A. Tiomanene may be a plausible precursor for acetylmajapolenes B and A. In addition, three known halogenated sesquiterpenes and two known halogenated C(15) acetogenins were found from other two unrecorded species collected at Pulau Karah, Terengganu and Pulau Nyireh, Terengganu, respectively. Some of these halogenated metabolites showed moderate antibacterial activity against some marine bacteria.

[Quinolone resistance in Gram negative rods in Iceland and association with antibiotic use]

OBJECTIVE

Fluoroquinolones are bacteriocidal drugs that are widely used to treat severe urinary and respiratory tract infections. Studies show that resistance to fluoroquinolones is continuously increasing both in Europe and the United States. The purpose of this study was to measure the frequency of fluoroquinolone resistance in the most prevalent Gram negative rods and look at the correlation with fluoroquinolone use over the last 8 years.

MATERIALS AND METHODS

All strains of Escherichia coli, Klebsiella sp., Proteus sp. and Pseudomonas aeruginosa identified from clinical specimens at the Department of Clinical Microbiology at the Landspitali University Hospital (LUH) during the time period 1.11.2006 to 31.1.2007. Antibiotic susceptibility testing was performed by disc diffusion tests and all strains were tested for ciprofloxacin susceptibility. Antibiotic resistance data for the last years were collected from the reports of the Department of Clinical Microbiology, but ciprofloxacin susceptibility was usually only tested for specimens from hospitalised patients and when there was resistance to two or more antimicrobial agents. Data on antibiotic use/sales was obtained from the State Epidemiologist at the Directorate of Health.

RESULTS

Of the 1861 strains tested, 104 fluoroquinolone resistant strains were identified during the study period, including 91 E. coli (87%), 8 Klebsiella sp. (8%) and 5 P. aeruginosa (5%). No fluoroquinolone resistant Proteus sp. was identified. There was a significant positive correlation between fluoroquinolone use and the frequency of resistant strains of E. coli and Enterobacteriaceae. The frequency of resistant E. coli strains was 6% and it differed significantly between age groups (p >0.001) and sex, 6% for females and 11% for males (p = 0.015). The ratio of fluoroquinolone resistant E. coli was highest in the LUH and homes for the elderly.

CONCLUSION

The frequency of fluoroquinolone resistance is increasing fast in Iceland but is still one of the lowest compared to the other European countries. The frequency is highest in the oldest age groups where the use of the quinolones is the greatest and there was a significant correlation between the quinolone use and the frequency of resistance in E. coli and Enterobacteriaceae. The results highlight the importance of prudent fluoroquinolone use and the need to monitor fluoroquinolone use and resistance.

Antimicrobial susceptibility of Klebsiella spp. and Proteus spp. from various organ systems of horses, dogs and cats as determined in the BfT-GermVet monitoring program 2004-2006

A total of 120 isolates of Klebsiella spp. and Proteus spp. collected from horses and small animals (dogs and cats) were screened for their susceptibility to 24 different antimicrobial agents. Klebsiella spp. were included from infections of the genital tract (GT) of horses (36 isolates) and the urinary/genital tract (UGT) from dogs and cats (17 isolates), while Proteus spp. were from small animal (dogs and cats) infections of the UGT (37 strains) and the skin (incl. ear/mouth) (30 isolates). In Klebsiella spp. resistance appeared most frequently to ampicillin (53-67%), sulfamethoxazole (19-29%) and potentiated sulfonamides (trimethoprim/sulfamethoxazole 1/19 combination) (19-24%). A further 29% of enrofloxacin resistant Klebsiella isolates were observed for the UGT of small animals. From the GT of horses for this antimicrobial agent there was no isolate detected with a comparably high minimum inhibitory concentration (MIC) value. In Proteus spp. highest percentages of resistance occurred against tetracycline (90-92%). Due to drug efflux proteins, high MIC values against this antimicrobial agent have been frequently reported in literature. In Proteus spp. relevant resistance percentages also occurred for potentiated sulfonamides (27-37%), sulfamethoxazole (24-37%) and chloramphenicol (24-37%).

Susceptibility of Human Pathogenic Bacteria to Antimicrobial Peptides from Sesame Kernels

Hospital infection caused by Gram-negative bacteria is a serious and common problem, especially in developing countries. Aiming to reduce these infections, this report focuses on the identification and characterization of novel antimicrobial peptides from sesame (Sesamum indicum) kernel meals. Thus, sesame flour was extracted and precipitated with ammonium sulfate (100%). After dialysis, a rich fraction was applied to affinity red-Sepharose CL-6B chromatography, followed by reversed-phase high-performance liquid chromatography. Mass spectrometry analysis indicated the presence of a major peptide with molecular mass of approximately 5.8 kDa in both cultivars. The bactericidal activities of antimicrobial peptides were evaluated against several human pathogens that had been effective only against Klebsiella sp., a Gram-negative bacterium responsible for human urinary infection. These data indicate the biotechnological potential of sesame peptides as an alternative method for hospital infection control and also the decrease of bacterial resistance to synthetic antibiotics.

Population-based laboratory surveillance for tribe Proteeae isolates in a large Canadian health region

The tribe Proteeae comprises the genera Proteus, Morganella and Providencia. Few studies have specifically investigated the epidemiology of infections caused by the Proteeae, and none has been conducted in a large non-selected population. The present study was a population-based laboratory surveillance in the Calgary Health Region (population 1.2 million), Canada during 2000-2005 that aimed to define the incidence, demographical risk-factors for acquisition and antimicrobial susceptibilities of Proteeae isolates. In total, 5047 patients were identified from whom Proteeae isolates were obtained (an annual incidence of 75.9/100 000), with females and the elderly being at highest risk. Incidence rates were 64.8, 7.7 and 3.4/100,000/year for the genera Proteus, Morganella and Providencia, respectively. Overall, 85% of infections were community-onset, and the overall rate of bacteraemic disease was 2.0/100,000. Compared with other species, Proteus mirabilis occurred at a much higher frequency, especially among females, and was less likely to be isolated from hospital-onset infections or to be part of a polymicrobial infection. Among isolates from community-onset infections, Providencia spp. were less likely to be from outpatients and more likely to be from nursing home residents. There were low overall rates of resistance to ciprofloxacin (4%) and gentamicin (5%), with Prot. mirabilis generally being the most susceptible. Members of the Proteeae were isolated frequently in both the community and hospital settings, but were infrequent causes of invasive disease. The occurrence, demographical risk-factors and microbiology of Proteeae isolates varied according to the individual species.

Detection of extended-spectrum beta-lactamases among Enterobacteriaceae by use of semiautomated microbiology systems and manual detection procedures

Three commercially available microbiology identification and susceptibility testing systems were compared with regard to their ability to detect extended-spectrum beta-lactamase (ESBL) production in Enterobacteriaceae, i.e., the Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, MD), the VITEK 2 System (bioMérieux, Marcy l'Etoile, France), and the MicroScan WalkAway-96 System (Dade Behring, Inc., West Sacramento, CA), using routine testing panels. One hundred fifty putative ESBL producers were distributed blindly to three participating laboratories. Conventional phenotypic confirmatory tests such as the disk approximation method, the CLSI double-disk synergy test, and the Etest ESBL were also evaluated. Biochemical and molecular characterization of beta-lactamases performed at an independent laboratory was used as the reference method. One hundred forty-seven isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, Serratia marcescens, Proteus mirabilis, Proteus vulgaris, and Morganella morganii were investigated. Of these isolates, 85 were identified as ESBL producers by the reference method. The remaining isolates were identified as non-ESBL producers; they were either hyperproducers of their chromosomal AmpC, Koxy, or SHV enzymes or lacked any detectable beta-lactamase activity. The system with the highest sensitivity for the detection of ESBLs was the Phoenix (99%), followed by the VITEK 2 (86%) and the MicroScan (84%); however, specificity was more variable, ranging from 52% (Phoenix) to 78% (VITEK 2). The performance of the semiautomated systems differed widely with the species investigated. The sensitivities of the conventional test methods ranged from 93 to 94%. The double-disk synergy test showed the highest specificity and positive predictive value among all test methods, i.e., 97% and 98%, respectively.

In vitro activities of three carbapenems against recent bacterial isolates from severely ill patients at Swedish hospitals

To study the in vitro activity of imipenem, meropenem and ertapenem against common pathogens isolated from patients in intensive care, haematology and dialysis/nephrology units at 7 Swedish university hospitals, a total of 788 isolates were collected during 2002-2003. The distribution of the isolates was as follows: Escherichia coli (n = 140), Klebsiella spp. (n = 132), Proteus spp. (n = 97), Enterobacter spp. (n = 113), Pseudomonas aeruginosa (n = 126), Acinetobacter spp. (n = 53) and Enterococcus faecalis (n = 127). The susceptibility to the 3 carbapenems was determined by E-test, and the MICs were interpreted according to SRGA criteria. All 3 carbapenems were highly active against Enterobacteriaceae. The overall susceptibility to imipenem, meropenem and ertapenem was 90%, 98% and 93%, respectively. Against Enterobacteriaceae, Enterobacter spp. excluded, ertapenem had an equal or lower MIC(90) than meropenem. Apart from being the most active carbapenem against Enterobacteriaceae, meropenem was also the most active carbapenem against P. aeruginosa, whereas imipenem was the most active drug against Acinetobacter spp. The carbapenems are still potent antibiotics. With the introduction of ertapenem, and an expected increase in the carbapenem consumption due to an increased prevalence of strains with extended-spectrum beta-lactamases, continuous surveillance of carbapenem resistance appears to be warranted, with special attention to P. aeruginosa, Enterobacter and Proteus spp.

Choice of antibiotic for empirical therapy of acute cystitis in a setting of high antimicrobial resistance

BACKGROUND

A high prevalence of antimicrobial resistance among urinary isolates in the Garhwal region of Uttaranchal.

AIMS

To identify the most appropriate antibiotic for empirical treatment of community-acquired acute cystitis on the basis of local antimicrobial sensitivity profile.

SETTINGS AND DESIGN

A prospective clinico-microbiological study including all clinically diagnosed patients with community acquired acute cystitis attending a tertiary care teaching hospital over a period of three years.

METHODS AND MATERIAL

Clean-catch midstream urine specimens, from 524 non-pregnant women with community-acquired acute cystitis, were subjected to semi-quantitative culture and antibiotic susceptibility by the Kirby- Bauer disc diffusion method. A survey was also conducted on 30 randomly selected local practitioners, to know the prevalent prescribing habits in this condition.

STATISTICAL ANALYSIS

The difference between the susceptibility rates of E. coli isolates to Nitrofurantoin and the other commonly prescribed antibiotics was analysed by applying the z test for proportion.

RESULTS

354 (67.5%) specimens yielded significant growth of E. coli.> 35% of the urinary E.coli isolates were resistant to the fluoroquinolones, which were found to be the most commonly used empirical antibiotics in acute cystitis. Resistance was minimum against Nitrofurantoin (9.3%, 33) and Amikacin (11.0%,39).> 80% of the fluoroquinolone-resistant strains were found to be sensitive to Nitrofurantoin.

CONCLUSION

The best in vitro susceptibility profile in our study has been shown by Nitrofurantoin and a significantly high proportion of the urinary E. coli isolates have already developed resistance to the currently prescribed empirical antibiotics, viz. the fluoroquinolones. In view of these in vitro susceptibility patterns, a transition in empirical therapy appears imminent.

[Microorganisms isolated from middle ear cultures and their antibacterial susceptibility in patients with chronic suppurative otitis media]

OBJECTIVES

This study sought to determine causative microorganisms of chronic suppurative otitis media and their antibacterial susceptibility.

PATIENTS AND METHODS

Bacteriologic results of middle ear swabs, agent microorganisms, and their susceptibility to antibiotics were evaluated in 70 patients (65 males, 5 females; mean age 21.1+/-1.3 years; range 19 to 25 years) with chronic suppurative otitis media.

RESULTS

No bacteria were isolated in 14% of the patients. Of 60 patients in whom bacteria were isolated, the most common bacteria was Pseudomonas aeruginosa (23%), followed by Staphylococcus aureus (18%), and Proteus spp. (17%). P. aeruginosa strains were susceptible to ceftazidime and imipenem (100%), ciprofloxacin (92%), and amikacin and gentamycin (85%); S. aureus strains were susceptible to methicillin and vancomycin (100%), ciprofloxacin (91%), sulbactam-ampicillin (73%), and gentamycin and trimethoprim-sulfamethoxazole (63%). Proteus strains were susceptible to ciprofloxacin (100%), ceftazidime (90%), and imipenem and gentamycin (70%).

CONCLUSION

Appropriate knowledge of antibacterial susceptibility of microorganisms will contribute to rational antibiotic usage and the success of treatment for chronic suppurative otitis media.

Quantitative bacterial micro-assay for rapid detection of serum phenylalanine on dry blood-spots: application in phenylketonuria screening

Phenylketonuria is an inherited metabolic disease, which is characterized by an increased level of serum phenylalanine. Quantitative measurement of phenylalanine in the serum of phenylketonuria patients is necessary to confirm the disease, and to distinguish phenylketonuria from other forms of hyperphenylalaninemia. In this study, we report a rapid and inexpensive micro-assay for simultaneous detection and quantitative measurement of serum phenylalanine on dry blood-spots. Analysis of the standard curve showed a broad linear range for phenylalanine from 120 to 1800μmol/L. Application of this method, the standard Guthrie bacterial inhibition assay and a high-performance liquid chromatography (HPLC) method for analysis of 34 samples from phenylketonuria patients and control samples produced comparable results, with the regression equation Y=0.994X+0.996. The advantage of this method over the Guthrie bacterial inhibition assay is its ability to measure serum phenylalanine quantitatively without false positive results. The method was successfully applied to dried blood-spots, serum and whole blood. The cost per sample is approximately 20–50 US cents, which is much less than for HPLC and commercial enzyme kits. The method can be automated, and is thus suitable for neonatal and mass screening for phenylketonuria, especially in developing countries where funding is a limiting factor.

Antimicrobial activity of flavonoids from Pelargonium radula (Cav.) L'Hérit

Flavonoids from Pelargonium radula (Cav.) L'Hérit were purified by column chromatography. Two fractions were obtained: F1 (main flavonoid isoquercitrin) and F2 (main flavonoid rutin). In vitro antimicrobial activity of F1 and F2 were tested against eleven species of bacteria and eleven species of fungi. Both fractions demonstrated strong inhibitory activity against Staphylococcus aureus, Proteus rettgeri, Candida tropicalis and Microsporum gypseum. Staphylococcus sp. (coagulase-negative) and Candida lusitaniae were strongly inhibited only by fraction F1 and Fusarium graminearum only by fraction F2.

Characterization and biological activities of two copper(II) complexes with diethylenetriamine and 2,2'-bipyridine or 1,10-phenanthroline as ligands

Two new mixed ligand copper(II) complexes with diethylenetriamine, 2,2'-bipyridine and 1,10-phenanthroline have been synthesized. The crystal and molecular structures of [Cu(dien)(phen)](ClO(4))(2) and [Cu(dien)(bipy)](BF(4))(2) (dien=diethylenetriamine, phen=1,10-phenanthroline, bipy=2,2'-bipyridine) were determined by X-ray crystallography from single crystal data. These two complexes have similar structures. The EPR spectral data also suggest that these complexes have distorted square pyramidal geometry about copper(II). Anti-microbial and superoxide dismutase activities of these complexes have also been measured. They show the higher SOD activity than the corresponding simple Cu(II)-dien/Cu(II)-PMDT (PMDT=N,N,N',N',N''-pentamethyldiethylenetriamine) complexes because of a strong axial bond of one of the nitrogen atoms of the alpha-diimine. Both the complexes have been found to cleave plasmid DNA in the presence of co-reductants such as ascorbic acid and glutathione.

Straightforward representation of antimicrobial chemotherapeutics susceptibility profiles in a private tertiary care hospital

Culture-based values for antimicrobial susceptibility of 28 antimicrobials against different bacteria isolated from clinical material in a tertiary care hospital were used to pick the most promising antimicrobials. Isolates originating from urinary tract, blood and pyogenic foci, enteric fever and enteritis were grouped. Antimicrobials, systemic or oral, exhibiting a 75% or more susceptibility were compartmentalized in relation to divergent clinical disorders. Retrospective categorized culture-based susceptibility values should help a rational prospective chemotherapeutic intervention against infectious syndromes encountered in hospital practice.

[Enzymatic resistance to beta lactam antibiotics within the genus Proteus and evaluation of Proteus mirabilis phenotypes and genotypes for resistance to third- and fourth-generation cephalosporins]

INTRODUCTION

The aim of this study was to evaluate betalactam resistance within the genus Proteus and characterize the betalactamases responsible for this resistance.

METHODS

We analyzed 99 strains (87, P. mirabilis; 10 P. vulgaris, and 2, P. penneri) isolated from patients at one University Hospital. Antibiotic susceptibility tests were performed according to NCCLS recommendations. Presence of extended spectrum betalactamases (ESBL) was inferred by both double disk diffusion tests and minimum inhibitory concentration (MIC) of third and fourth generation cephalosporins alone and in the presence of clavulanic acid. Isoelectric points (pI) of the enzymes were estimated by isoelectrofocusing and the presence of the encoding genes was confirmed by polymerase chain reaction (PCR).

RESULTS

A broad spectrum betalactamase could be detected in those isolates (28%) resistant to penicillin and first generation cephalosporins while CTX-M-2 enzyme could be detected in P. mirabilis isolates resistant to third and fourth generation cephalosporins (18%). One of the P. vulgaris displayed reduced susceptibility to cefotaxime due to an enzyme of pI 7.4, while resistance to cefotaxime in one P. penneri was related to an enzyme of pI 6.8. Both enzymes were active on cefotaxime (1,000 mg/l) in the iodometric assay.

CONCLUSION

The broad extended spectrum betalactamase within genus Proteus was TEM-1, while CTX-M-2 was the ESBL responsible for the third and fourth generation cephalosporins in P. mirabilis. In P. vulgaris and P. penneri this resistance was associated with the hyperproduction of the chromosomal encoded betalactamase.

Synergy between cephalosporin and aminoglycoside antibiotics against Providencia and Proteus

Clinical isolates of Providencia and Proteus with relative aminoglycoside resistance were tested for susceptibility to combinations of gentamicin or tobramycin with cephalothin or cefazolin. The minimal bactericidal concentration of aminoglycoside for one-third of the strains was reduced by fourfold or more in the presence of one-fourth of the minimal bactericidal concentration of either cephalosporin. This effect was achieved by clinically attainable concentrations of cephalothin or cefazolin.

A potent sperm motility-inhibiting activity of bioflavonoids from an ethnomedicine of Onge, Alstonia macrophylla Wall ex A. DC, leaf extract

The methanol extract (ME) and the n-butanol fractions of methanolic extract of Alstonia macrophylla Wall ex A. DC leaves were investigated on the forward motility (FM) of mammalian (goat and human) spermatozoa. The ME at 600 microg mL-1 as well as fraction B at 100 microg mL-1 concentrations showed marked inhibition of sperm FM in both goat and human species when tested by microscopic and spectrophotometric methods. Approximately 60-80% of the goat spermatozoa lost their FM when treated with 600 microg mL-1 of ME and 100 microg mL-1 of fraction B. At 100 microg mL-1 concentration, fraction B showed 90% loss of FM in human spermatozoa, while fraction B at 400 microg mL-1 concentration showed complete inhibition of sperm FM at 0 min. The inhibitory activity of fraction B increases with increasing concentration in a dose-dependent manner. Phytochemical study of the extract revealed that the leaf contains tannins, flavonoids, sterols, triterpenes, alkaloids and reducing sugars. Further fractionation and purification of the bioactive n-butanol part of ME showed the presence of ursolic acid (fraction B), beta-sitosterol (fraction A), beta-sitosterol glucoside and a mixture of minor compounds (fraction C, detected on thin-layer chromatography). The results reveal that fraction B (ursolic acid), a pentacyclic triterpene, has the potential of sperm motility inhibition and can serve as a topical vaginal contraceptive.