Quorum Sensing Interfering Strategies and Their Implications in the Management of Biofilm-Associated Bacterial Infections

Abstract The bacterial species employ various types of molecular communication systems recognized as quorum sensing for the synchronization of differential gene expression to regulate virulence traits and biofilm formation. A variety of quorum sensing inhibitors; molecules that interfere with quorum sensing among bacteria have been examined which can block the action of autoinducers. Moreover, the studies have scrutinized various enzymes for their quorum quenching activity resulting in the degradation of signaling molecules or blocking of gene expression. So far, the studies have found that these approaches are not only capable to reduce the pathogenicity and biofilm formation but also resulted in increased bacterial susceptibility to antibiotics and bacteriophages. The effectiveness of these strategies has been validated in different animal models and it seems that these practices will be transformed in near future to develop the medical devices including catheters, implants, and dressings for the prevention of bacterial infections. Although many of these approaches are still in the research stage, the increasing library of quorum quenching molecules and enzymes will open innovative perspectives for the development of antibacterial approaches which will extend the therapeutic arsenal against the pathogenic bacterial species.

Molecular Detection of Giardia lamblia and Cryptosporidium parvum in Different Water Sources of District Bannu, Khyber Pakhtunkhwa, Province of Pakistan.

Background: Cryptosporidium parvum and Giardia lamblia are intestinal parasites that predominantly causes "waterborne" infections that are transmitted through consumption of contaminated water. Both parasites typically cause an acute short-term infections with selflimiting diarrhea as the main symptom in people with intact immune systems. However, in immunocompromised individuals, the symptoms are particularly severe and might be fatal. Methods: The study was carried out in District Bannu Khyber Pukhtunkhwa, Pakistan for the detection of G. lamblia and C. parvum parasites in drinking water in different villages/localities (Kakki, Jamon Road, Kotka Juma Khan, Sokari, Mandan and Bannu City). Water samples n=75 were collected from different water sources between 1st August 2011 to 30th January 2012. These samples included tap, pond, borewell and hand pump water that were filtrated and residue was subjected to amplify by PCR. Results: Overall prevalence of parasites was 36% (25/75), containing tap 17.64% (9/51) and pond water 75% (6/8), bore well water 41.66% (5/12) and hand pump water 50% (2/4). Similarly over all prevalence rate of tap water for C. parvum was 7.84% (4/51) while for G. lamblia was 9.80% (5/51) positive. The present study revealed that the people of the area should use the cleaned and filtered water. Conclusion: Contamination of water with G. lamblia and C. parvum was found in water sources especially the drinking ones, of District Bannu which need proper water treatment to decontaminate and large scale studies are needed.

Malaria: Still a Health Problem in the General Population of Bannu District, Khyber Pakhtunkhwa, Pakistan.

Aims: This study was aimed to know the burden of malaria infection and to re-evaluate its high prevalence in general population of Bannu District. Study Design: The current study was designed to re-evaluate the high prevalence of malaria and its demography in the human population of Bannu District. Place and Duration of the Study: This study was conducted during the months of May to September 2011 in local population of the Bannu District. Methodology: A total of 823 blood samples were randomly collected from both sexes; 513 males and 310 females of varying age groups <1 up to 50< years (mean 26.3± 9.1). Blood was drawn by pricking a left hand finger by using a sterilized lancet. Both thick and thin smears were prepared and examined through microscope for the detection of malarial parasites along with their impact on the general hematology. Results: Out of 823 blood samples, 223(27.1%) subjects were found positive for Plasmodiasis, while the distribution of species prevalence was observed as 186 (22.6%) and 25 (3.04%) for Plasmodium vivax, and Plasmodium falciparum, respectively along with a mixed infection of 12(1.46%). Variation with high incidence (42.65%) was found in the age group of 21-30 years. Moreover, males were found to be more malaria infected (30.64%) than females (24.95%). In addition, the prevalence of Plasmodiasis was found more frequent in rural population (33.42%) as compared to urban (21.00%) population. Conclusion: The present study revealed that the burden of malaria was high in rural areas of Bannu District and more attention is needed to overcome and control the high prevalence of malaria in this region.

Investigations of heavy metals in different medicinal plants.

The present study was conducted to determine the concentration of heavy metals in some selected medicinal plants taken from District Karak, Khyber Pakhtunkhwa, Pakistan. Essential and non essential heavy metals such as Zn, Fe, Mn, Cu, Ni, Cr, Pb and Cd were investigated in Rhyzia stricta, Withania coagolans, Conyza canadensis, Steleria media, Medicago denticulata, Parthenium hysterophorous, Malvastrum tricuspidatum and Launaea nodicaulis by using Atomic Absorption Spectrometry. Plants showed different metal concentration in the range of: 10.11-55.98mg/kg for Zn, 40.47-101.87mg/kg for Fe, 29.11-105.46mg/kg for Mn, 15.06- 34.52mg/kg for Cu, 1.02-10mg/kg for Ni, 0.01-0.76mg/kg for Cr, 0.99-15.46mg/kg for Pb and 0.10-1.41mg/kg for Cd. High contents of Fe and Mn were found in all eight plants. Other heavy metals were present in low quantity. The purpose of this study was to identify each type of metal associated with a given plants contaminated by environmental pollution and also to highlight the toxic heavy metals present in these plants.

Pollution Based Study of Heavy Metals in Medicinal plants Aloe vera and Tamarix aphylla.

The main objective of this study was to generate perception in community regarding pollution of heavy metals contained in Aloe vera and Tamarix aphylla plants which have wide range of medicinal use but having toxic concentration of heavy metals. The plant samples were collected at three different areas referred as spots i.e. polluted (spot 1), less polluted (spot 2) and non- polluted (spot 3) from District Kohat, Khyber Pakhtunkhwa, Pakistan. In the present study, essential heavy metals such as Cobalt (Co), Nickel (Ni), Chromium (Cr), Copper (Cu), Iron (Fe) and Zinc (Zn) and non-essential heavy metals Cadmium (Cd), Lead (Pb) were analyzed in Aloe vera leaves and Tamarix aphylla by using Flame atomic absorption spectrophotometer. Heavy metals concentration in different spots were found to be in order as Spot 1> Spot 2>Spot 3 with the concentration range of found heavy metals., Cd 0.25-0.51 mg/kg, Pb BDL-15.23, Co 1.90-3.31mg/kg, Ni 2.98-4.01 mg/kg, Cr 4.86- 6.01 mg/kg, Cu 2.32-3.01 mg/kg, Fe 12.42-22.47 mg/kg, Zn 34.53-53.08 mg/kg for Aloe vera leaves and concentrations of the same heavy metals like Cd 0.13-0.31 mg/kg, Pb 1.00-18.01 mg/kg, Co 0.25-2.90 mg/kg , Ni 3.75-5.93 mg/kg , Cr 3.83-5.32 mg/kg , Cu 1.01-1.90 mg/kg, Fe 23.65-30.10 mg/kg , Zn 13.70-25.63 mg/kg were observed in the bark of Tamarix aphylla. Thus it was concluded from the present study that the samples collected from polluted area were found more contaminated with heavy metals as compared to less polluted and nonpolluted area.