Open Access Short communication

Molecular Characterization, Multiple Drug Resistance, and Virulence Determinants of Pseudomonas aeruginosa Isolated from Lebanon

Sima Tokajian, Rola Timani, Nahla Issa, George Araj

Microbiology Research Journal International, Page 243-250
DOI: 10.9734/BMRJ/2012/2217

Aims: Typing and characterization of 100 P. aeruginosa clinical isolates by pulse field gel electrophoresis (PFGE) to detect changes in the clonal composition of local strains and to correlate banding patterns with site of infection, drug resistance and Type III secretion system effectors.
Methodology: A total of 100 P. aeruginosa isolates obtained from clinical specimens were used to study resistance profiles, PFGE banding patterns and virulence determinants.
Results: Results from antimicrobial susceptibility testing yielded showed that 77 of the strains were multi drug resistant (MDR). Grouping isolates as non-susceptible when tested intermediate and resistant according showed showed that resistance was 25% each for imipenem and piperacillin-tazobactam, while it was 29% for ceftazidime these drugs are among the ones most commonly used in treating infections caused by P. aeruginosa. Studying effectors released by the type III secretion system including exoU and exoS revealed that 48% of the isolates harbored exoS toxin gene and 46% the exoU, with 3% having both and 8% having none. When the different pulsotypes were compared on a dendogram, 45 groups emerged showing vast differences among the isolates.
Conclusion: This study showed the emergence of drug resistance in P. aeruginosa against the antimicrobial agents being routinely used for treatment and revealed the likely presence of co-selected traits that result in highly virulent and resistant strains. Further clinical investigations are warranted to combat infections caused by this important human pathogen in Lebanon.

Open Access Original Research Article

Antimicrobial Resistance in Pathogens Causing Pediatrics Bloodstream Infections in a Saudi Hospital

Maha A. Abo-Shadi, Aisha A. Al-Johani, Ahmad A. Bahashwan

Microbiology Research Journal International, Page 212-227
DOI: 10.9734/BMRJ/2012/2033

Background: Bloodstream infection (BSI) is one of the most common life-threatening conditions in hospitalized pediatrics especially if associated with resistant microbes.
Aims: To determine the incidence, predisposing factors, microbiological and antimicrobial resistance patterns in suspected BSI pediatric patients in a Saudi hospital.
Place and Duration of Study: Different wards of Madinah Maternity and Children's Hospital, Saudi Arabia, during one year period from July 1, 2009 to June 30, 2010.
Methodology: Blood cultures were performed to all cases (n= 11968) using Bactec 9240 instrument Blood Culture Systems. Microorganisms were identified by colony morphology, Gram stain and biochemical profiles. BD Phoenix™ was used in confirmation of identification of all BSI Gram-negative isolates. Antibiotic susceptibility pattern of isolates was further done by using disk diffusion method.
Results: 728 cases (6.1%) were diagnosed with BSI after having a one positive blood culture. The overall mortality rate was 11%. Gram-positive, Gram-negative and yeast accounted for 63.8%, 31.6% and 4.6% of the total isolates, respectively. Coagulase-negative staphylococci were the most prevalent Gram-positive isolates (44%); while Serratia marcescens and Klebsiella pneumoniae were the most common Gram-negatives. Gram-positive bacteria were mostly sensitive to cephalothin (82.3%) and vancomycin (72.2%), while Gram-negative bacteria were mostly sensitive to ciprofloxacin (93%), piperacillin/tazobactam (92.9%), and meropenem (89.8%).
Conclusion: The incidence rate of BSI is highest in ICU neonates. Therefore, special attention should be given to the quality of care provided for them to improve safety. There was appreciable resistance to commonly used antibiotics; and continued monitoring of antibiotic resistance is of great importance to ensure the proper use of antibiotics and to detect any increasing trends in resistance.

Open Access Original Research Article

Use of a Steam Generator for Disinfection of Hospital Ward Room Surfaces

Sonia De Lorenzi, Germano Salvatorelli, Gianfranco Finzi, Paola Cugini

Microbiology Research Journal International, Page 228-232
DOI: 10.9734/BMRJ/2012/1959

Objectives: The present work examines the ability of a method — based on saturated overheated dry steam — to decontaminate surfaces in patient rooms in a surgery ward.
Study Design: An experimental study.
Place and Duration of Study: The investigation was carried out in two rooms of a surgical ward at the Villa Erbosa health care facility in Bologna (Italy) over a period of three weeks.
Methodology: Samples, using 24 cm diameter contact plates containing an agar-base medium, were taken before and after steam decontamination obtained using a professional steam generator.
Results: After steam treatment, the number of CFU (colony forming unit) present on the surfaces analyzed was reduced by 88.41%.
Conclusion: These results are significant and indicate that the use of steam provides good results in terms of decontamination of the surfaces in ward rooms.
Furthermore steam not leaves residues that could be the source of subsequent chemical contamination of the surfaces.

Open Access Original Research Article

Optimization of Cultural Conditions for Cochliobolus heterostrophus Isolates from Infected Maize Plants from Different Agricultural Zones of Pakistan

Iffat Naz, Shama Sehar, Irum Perveen, Abdul Rehman, Amber Hameed, Yasmin Ahmad, Safia Ahmed

Microbiology Research Journal International, Page 233-242
DOI: 10.9734/BMRJ/2012/2019

Southern corn leaf blight caused by Cochliobolus heterostrophus is a major foliar disease of maize crop in Pakistan. The disease affects leaves, leaf sheaths, ears and maize grains. Suitable physiological conditions which include different nutrient media, temperature, pH, carbon and nitrogen sources were determined for growth and reproduction of the pathogen. Among all media used viz, the best supporting medium was found to be Richard’s agar for the growth of pathogen after 7 days of incubation. Different temperatures (20, 25, 30 and 35ºC) were selected for mycelia growth of the pathogen, among which maximum growth was found to be at 30ºC (80 mm colony size) and minimum at 35ºC (35 mm). Maximum radial colony growth of the pathogen was observed at neutral pH (80 mm). Sucrose and potassium nitrate (KNO3) were found to be the most appropriate sources of carbon and nitrogen respectively.

Open Access Original Research Article

Antimicrobial Profile of Selected Snake Venoms and Their Associated Enzymatic Activities

R. I. Shebl, A. F. Mohamed, A. E. Ali, M. A. Amin

Microbiology Research Journal International, Page 251-263
DOI: 10.9734/BMRJ/2012/2091

Aims: To investigate the antiviral and antibacterial profile of several crude snake venoms and to assess some of their enzymatic activities.
Methodology: The antiviral activities of Naja haje, Bitis arietans, Naja nigricollis and Echis carinatus snake venoms were investigated against Herpes simplex virus type1, Rift valley fever virus and Vesicular stomatitis virus using the end point of cytopathic effect method. Antibacterial activities of Bitis arietans, Cerastes cerastes, Echis carinatus, Vipera lebetina, Naja naja, Pseudechis australis, Naja nigricollis and Naja haje venoms were examined against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa using disc diffusion method. Microdilution method was used to determine the venom's minimum inhibitory concentration. L-amino acid oxidase and phospholipase A2 activities of crude venoms were evaluated using enzymatic assays.
Results: Naja nigricollis, Bitis arietans and Echis carinatus snake venoms exhibited significant antiviral activities against all test viruses, except for N. haje treated cells. The mean depletion of viral infectivity titer of venom pretreated cells was higher than its depletion post viral infection for all three venoms showing antiviral activities. Naja nigricollis exhibited the highest antiviral activity against test viruses and recorded a mean depletion of viral infectivity titer in venom pretreated cells of 3.8 log (10) / ml , 3.2 log (10) / ml and 2.5 log (10) / ml for HSV-1, RVFV and VSV, respectively. Pseudechis australis, followed by Naja naja and Naja nigricollis venoms, showed the highest inhibitory activity against test bacteria with inhibition zones ranging from 11-17 mm, 8-14 mm and 8-13 mm, respectively. Minimum inhibitory concentrations of test venoms against different bacterial strains ranged from 156 μg / ml to 1.25 mg / ml. Maximum L- amino oxidase activity was detected in Naja naja, Cerastes cerastes and Pseudechis australis. The highest Phospholipase A2 activity was identified in Bitis arietans, Pseudechis australis, Naja naja and Naja nigricollis.
Conclusion: It can be concluded that snake venoms or their bioactive derivatives can be promising therapeutic agents against some microbial infections. Further investigations will be carried out for purification and more characterization of the biologically active components in snake venoms.

Open Access Original Research Article

Detection of Mutation in gyrA and parC Gene on Resistant Salmonella enterica Serovars. Isolated from Two Hospitals in South East Nigeria

N. E. Onyenwe, O. E. Adeleke, T. I. Mbata, G. N. Udeji, J.C. Okoro

Microbiology Research Journal International, Page 264-276
DOI: 10.9734/BMRJ/2012/1595

Aim: To detect the resistant pattern and existence of the genes responsible for floroquinolone-resistant in the quinolone-resistant determining regions (QRDR’s) of S. enterica serovars.Typhi.
Study Design: The Stool samples from Patients with symptoms of enteric fever, from different units and wards from two hospitals in Southeast region of Nigeria, were used for the surveillance.
Place and Duration of Study: The study was carried out in the Department of Microbiology and Biotechnology, Nigerian Institute for Medical Research, Lagos, between July and December, 2011.
Methodology: 50 isolates of Salmonella enterica serovar.Typhi were screened for the antibiotics susceptibility pattern, using multidisc agar diffusion and E-test. Double disc synergy Test (DDST) reported the presence of ESBL’s strains. The DNA amplification was performed by PCR using HOT FIREPol ® DNA polymerase with 25mMMgcl2. DNA –sequencing of the (QRDR’S) of gyrA (n= 32) and parC (n=3), was performed using sanger sequencing ABI 3730 x l, Applied Biosystems.
Results: A total of 39(78%) of the S. enterica produced β-lactamase. ESBL’s positive strains were 17(34%) and 46(92%) isolates were Multi-Drug Resistant S. typhi (MDRST). Sequencing of the mutations in gyrA gene of the (QRDR’s) was at Asp-87- Gly and Asp-87- Asn or at Ser-83- Tyr, while mutations in parC 3(6%), were at Asp-87- Gly.
Conclusion: Chromosomal encoded ESBL’s and mutations were found to be responsible for the MDRST. Ceftriazone and levofloxacine were found to be significant alternatives in treating S. enterica serovar.Typhi. This is the first report of mutation in both gyrA and parC genes in S. enterica serovar.Typhi in Southeast Nigeria.

Open Access Original Research Article

Prevalence of Vaginal Pathogens Associated with Genital Tract Infections in Ogun State, Nigeria

O. O. Bello, O. O. Mabekoje, M. O. Efuntoye, T. K. Bello

Microbiology Research Journal International, Page 277-289
DOI: 10.9734/BMRJ/2012/1481

Aims: The occurrence of vaginal pathogens associated with genital tract infections [GTIs] was investigated in this study.
Study Design: Over a three-month period, 106 High Vaginal Swab [HVS] samples were obtained from women with genital tract infections [GTIs] within the ages of 15 – 50 years attending In- and Out- patients clinic at General Hospital, Ijebu-Ode, Ogun State, Nigeria and percentage frequencies of isolates were determined comparatively.
Place and Duration of Study: Collections of samples were made at General Hospital, Ijebu-Ode, Ogun State while microbiological analyses on samples were carried out at the Department of Microbiology and Parasitology, Olabisi Onabanjo University Teaching Hospital [OOUTH], Sagamu, Ogun State, between August and November, 2011.
Methodology: Samples were screened for the presence of vaginal pathogens using conventional microbiological techniques. Potato dextrose agar [PDA] was employed to isolate and enumerate Candida species. Chocolate agar was used for the isolation of Neisseria gonorrheae, while Columbia agar base in 10% CO2-enriched atmosphere was employed for the isolation of Gardnerella vaginalis. Microscopic examinations of smears were carried out to determine the presence of Trichomonas vaginalis. Paired sample t-test was employed to analyze results statistically.
Results: Candida species recorded the highest prevalence of 58 [54.7%], followed by Trichomonas vaginalis 27 [25.5%], Gardneralla vaginalis 12 [11.3%], while Neisseria gonorrhea recorded the least prevalence of 09 [8.5%]. Among the Candida isolates obtained, Candida albicans had the highest prevalence of 39 [67.2%], followed by 11 [19%] Candida tropicalis, 6 [10.3%] Candida parapsilosis while the least occurred was Candida krusei with 2 [3.5%]. Results also showed that the incidence of Candida species was highest within the age group of between 21 and 30 years except Candida tropicalis which recorded highest incidence within the age range of 15 – 20 years. Statistical analyses established that there was no significant difference between the incidence of Candida sp and other vaginal pathogens.
Conclusion: Vaginal pathogens are directly associated with genital tract infections and this is on the high side among women in the developing world like Nigeria. This calls for commitment to routine evaluation and appropriate intervention in antenatal clinics.