Microbiol. Res., Volume 3, Issue 1 (January 2012) – 14 articles

Casein glycomacropeptide (GMP) is known to promote the in vitro growth of Bifidobacteria and Lactobacilli. In this paper, we used conventional culture techniques and fluorescent in situ hybridization (FISH) techniques to investigate the effect of casein GMP on mice fecal microbiota. The population structure of the intestinal microbiota, including Lactobacillus, Bifidobacteria, Enterococcus, coliforms and Enterobacteriaceae, was tested and compared. After consecutive administration of casein GMP for 15 days, numbers of Lactobacillus and Bifidobacteria increased significantly (P < 0.01), numbers of Enterobacteriaceae and Coliforms decreased significantly (P < 0.05) while no significant changes were observed for Enterococcus. The detection limits of FISH technique were significantly lower (P < 0.01) than the traditional culture method. These results suggested that consumption of casein GMP had a prebiotic effect on male BALB/c mice. Casein GMP helped establish a healthier intestinal microbiota. Additionally, FISH was proved to be a rapid and relatively low-cost detection method that can be used to further our understanding of human intestinal microbiota. Full article

The aim of the present study was to evaluate the use of different analytical units and the influence of storage under refrigeration on the detection of Salmonella sp. in naturally contaminated poultry carcasses. One hundred and thirty samples were collected during the production process soon after chilling (postchiller phase). Fifty-five samples were analyzed in up to 2 h after collection and 65 samples were analyzed after 72 h of storage. Pathogen screening was based on three different analytical units and a comparison was made between them. Carcasses were initially rinsed with 400 mL of diluent, and three different analytical units were incubated: total rinsing volume (TRV), a single 30 mL aliquot of the rinsing volume, and 25 g of skin from different areas of the carcass. Of all samples analyzed, 60% were positive for Salmonella sp. From the samples collected at the post-chiller phase, 57% were positive for the pathogen and 52.31% of these were detected by TRV; a better statistical performance (P < 0.05) when compared to the other analytical units. Of the refrigerated samples, 63% were contaminated, but there were no significant differences between analytical units (P > 0.05). There were no significant differences between the number of positive samples from the post-chiller phase and after 72 h of refrigeration. It was also seen that the use of different analytical units (one for the post-chiller phase and another for the refrigerated samples) in samples coming from the same production lot may give different results. Full article

Diagnosis of HIV in children younger than 18 months can be challenging in developing countries because requires the use of HIV virological tests. In this study we describe the experience with three commercial assays, HIV-1 DNA polymerase chain reaction (PCR) (Roche Amplicor 1.5) with dried blood spot, HIV-1 RNA PCR (Roche COBAS TaqMan) with plasma and reverse transcriptase activity assay (Cavidi Exavir Load 3) with plasma in a rural setting of India. Sensitivity and specificity were 98.1% (95% confidence interval [CI] 90-100) and 99.3% (95% CI 97.9-99.9) for the HIV-1 RNA PCR assay, 66.7% (95% CI 29.9-92.5) and 100% (95% CI 96.8-100) for the HIV-1 DNA PCR assay, and 100% (95% CI 48-100) and 98.7% (95% CI 92.8-100) for the reverse transcriptase activity assay respectively. The low sensitivity of the HIV-1 DNA PCR assay in this setting is worrisome and warrants further investigations. Full article

The Dengue virus is the main arbovirus that affects man in terms of morbidity and mortality. The detection of the virus is very important for epidemiological surveillance, so here we propose to standardize and compare the immunodot blot (IDB) and multiplex reverse transcriptase-polymerase chain reaction (M-RT-PCR) techniques to detect and characterize the dengue virus (DENV) serotypes in samples of Aedes aegypti larvae. Thus, the IDB and M-RT-PCR techniques were standardized using macerated samples of larvae collected in nature. The use of monoclonal antibodies in IDB has not shown great results, but DENV detection through this method was possible using polyclonal antibodies. The distinction of serotypes 1, 2 and 3 was carried out by M-RT-PCR. Full article

The aim of this study was to evaluate the in vitro antimicrobial activity of a methanolic extract of Salvadora persica solution on Helicobacter pylori isolated from duodenal ulcer. Over 22 strains of H. pylori were isolated from duodenal ulcer from August 2010 to June 2011. The S. persica stem was purchased from a local herb market and finely powdered. Extraction was performed with 60% methanol using a soxhlet extractor for 48 h until the solvent turned colorless while being incubated in an oven at 40 °C for 48 h till dried. Dry powder was used to determine antimicrobial activity by the agar ditch method. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extract were determined by the agar dilution method. At concentrations of 10, 100, 200, 500 µg/mL, no zone of inhibition around the ditches was observed while a clear zone of inhibition (12 mm) was detected at 1000 µg/mL concentration for all the isolates. The best antimicrobial activity was observed at MIC 1000 µg/mL (P ≤ 0.05). Furthermore, 10 out of 22 isolates were inhibited at 750 µg/mL of the extract. The MBC results showed that at a concentration of 1000 µg/mL all cells were dead while at a concentration of 750 µg/mL of S. persica a few H. pylori cells were still able to form colonies on Brucella agar supplemented with sheep red blood cells and antibiotics. From the above results it can be concluded that high concentration of S.persica could inhibit the growth of H. pylori and MIC and MBC were similar at that concentration. Full article

Hepatitis B virus (HBV) continues to cause serious health problems in developing countries. Neonatal infection with HBV, which is often acquired during delivery, carries a high risk resulting in persistent infection. This research aims to detect the prevalence of Hepatitis B surface Antigen (HBsAg) among pregnant women in our location of study. One hundred and eighty (180) sera samples were screened among pregnant women aged 13-49, using standard enzyme-linked immunosorbent assay (ELISA) method. Structured questionnaire were administered to the subjects to obtain demographic and other relevant data. Overall result showed that 31 (17.2%) were found to be positive for HBsAg among the total subjects screened. The highest prevalence was found among those aged 20-29 with 11 (6.1%) seropositivity (χ² = 7.902; P = 0.048). Considering occupational distribution of volunteer subjects, a high prevalence of 12 (6.7%); P < 0.05 was recorded among house wives, which shows a measure of significance compared to other women screened. Furthermore, based on various risk factors subjects with history of surgery and use of unsterilized sharp instruments recorded 15 (8.3%) prevalence (P = 0.233; P > 0.05). How ever, women in their second trimester of pregnancy recorded a higher prevalence of 23 (12.8%):(P = 0.080; P < 0.05). This study therefore emphasizes the public health importance of HBV among pregnant women and equally suggests that children born to women with Hepatitis B Virus, be closely monitored for infection beyond the one and the half years of age, this also calls for a proper enlightenment on the dangers posed by the virus, while a well designed vaccination schedule is advocated among the general population. Full article

Consumption of contaminated drinking water heavily contributes to the burden of gastrointestinal waterborne diseases. Conventional detection methodologies present several shortcomings, such as indirect measure of indicator species, low throughput and time consume. DNA chips have the potential to serve as surveillance systems for the simultaneous detection of pathogens overcoming these limitations. We have developed a DNA chip for simultaneous detection of multiple waterborne pathogens. Species specific DNA probes were implemented on a microarray, for microorganism detection. Present study reports the results of one untreated water sample analyzed by conventional methods and by the DNA chip. The results were concordant for the mandatory organisms (total coliforms, Escherichia coli, fecal enterococci) using both methods, reinforcing the utility and proof-ofconcept of the DNA chip. However, it is necessary a prior enrichment in a culture medium in order to obtain a positive signal using the DNA chip. The DNA chip may be a valuable distinctive tool for waterborne pathogens detection Full article

Chlamydia trachomatis is the most common cause of sexually transmitted infection. In 75% of women and 50% of men infection is asymptomatic. According to World Health Organization reports, the number of new genital infections with Chlamydia trachomatis reaches 100 million annually. The sensitivity and specificity of nacid amplification tests are 95% and 99%, respectively. Urine samples can provide a non-invasive method of testing for the detection of Chlamydia trachomatis by polymerase chain reaction (PCR). The aim of this study was to evaluate the prevalence of Chlamydia trachomatis infection in pregnant women referred to a teaching hospital affiliated to Shiraz University of Medical Sciences. Urine samples were obtained from 210 pregnant women and investigated microscopically and macroscopically by urinalysis. Precipitants were also used for DNA extraction and PCR test for detecting Chlamydia trachomatis. Among 210 urine specimens from women aged 15–39 years, none were positive for Chlamydia trachomatis by PCR. In spite of the high sensitivity and specificity of PCR, and the elimination of inhibitory effects on PCR test, no pregnant woman was positive for Chlamydia trachomatis. Here, we suggest that a larger sample should be studied and other sensitive methods could also be used in the future. Full article

In Marocco, many aspects of human asymptomatic visceral leishmaniasis (VL) still have to be clarified and little information is available about the factors that predispose individuals to asymptomatic infection. A prospective study was carried out in 889 healthy children under the age of 15 years living in two provinces in the endemic area in northern Morocco (the provinces of Taounate and My Yacoub) from April to May 2010. The aim of the study was to evaluate the prevalence and the socio-economic and environmental characteristics associated with infection by Leishmania infantum. The Montenegro skin test (MST) was used to detect asymptomatic infection. The prevalence of transmission of infection was 11.4% and approximately 2 times higher in Taounate than in My Yacoub, as measured by MST. Asymptomatic infection was associated with gender, age, presence of familial links, proximity to chickens, and the number of people in the house and locality, but it was not associated to education status, presence of dogs, livestock waste, sewage disposal, water supply system or use of insecticides Full article

The parks of Mumbai are frequently visited by local residents every morning and evening. However, there are no reports on the occurrence of keratinophilic fungi in these areas. The purpose of this research was to study the occurrence of keratinophilic fungi in the public parks of Mumbai. One hundred soil samples were collected from five public parks: Kamla Nehru Park, Powai Garden, CD Deshmukh Garden, Five Gardens and Chota Kashmir. Keratinophilic fungi were isolated by the hair baiting technique using human hair as keratin bait. The cultures were identified using macroand micro-morphological features. Identification was also confirmed by the BLAST search of sequences of the ITS1-5.8S-ITS2 rDNA region against the NCBI/Genbank data and compared with deposited sequences. The ability of these fungi to use human hair was also evaluated by release of protein in liquid media. A total of 75 strains of keratinophilic fungi were recovered from 100 (75.0%) soil samples. The isolated fungi were composed of eleven species of eight genera: Arthrographis kalrae, Auxarthron conjugatum, Chrysosporium indicum, C. queenslandicum, C. zonatum, Gymnascella dankaliensis, G. hyalinospora, Microsporum gypseum (15.0%), Myriodontium keratinophilum, Trichophyton mentagrophytes and Uncinocarpus reesii. These fungi can release 148.8-307.6 μg/mL protein in liquid media when grown on human hair in shake flask culture and also decompose 16.2-38.6% of human hair after four weeks of incubation. Our study indicates that keratinophilic fungi are to be found in the soils of various public parks in Mumbai and that human hair can be a source of pathogenic fungi. Full article

Use of empirical antibiotics in neonates with risk factors of early-onset neonatal sepsis (EOS) is a common practice. A laboratory parameter is needed to help in the accurate diagnosis of EOS to avoid unnecessary use of antibiotics. The aim of this prospective observational cohort study was to compare the statistical validity of cord blood interleukin-6 (IL-6) with conventional sepsis screening as an early diagnostic marker for EOS. Eighty-seven neonates with antenatal risk factors for sepsis were followed up for 72 h for the development of EOS. Cord blood was collected for measurement of IL-6 concentrations. Blood culture and conventional sepsis screening (total leukocyte count, absolute neutrophil count, C-reactive protein and micro-erythrocyte sedimentation rate) were sent for analysis soon after delivery. The study group comprised of symptomatic neonates with positive blood culture (n = 36). An equal number of gestational-age matched asymptomatic neonates without risk factor of sepsis served as controls. Statistical validity of IL-6 was compared with sepsis screening parameters as the diagnostic marker for EOS. Gram negative organisms were the predominant cause of EOS. The most commonly isolated organism was Acinetobacter baumanii. The sensitivity and specificity of IL-6 with a cut-off value of 40.5 pg/mL and area under curve of 0.959 were 92.3 and 90.48%, respectively. In contrast, the sensitivity and specificity of different parameters of sepsis screening ranged from 37.5–68.75% and 47.95–57.35%, respectively. In conclusion, cord blood IL-6 can be used as a highly sensitive and specific early diagnostic marker of EOS at a cut-off concentration of 40.5 pg/mL. Full article

Biological activity of water can be apparently judged by the colonization of bacteria (microbes). In order to find out the extent of pollution and the relationship between inorganic matters and microbiota, a quantitative and qualitative analysis of bacteria in various types of sewage waters, namely sewage water by the residential colonies (group I), industrial waste water (group II), sewage treatment hub (group III), unorganized collected waste water (group IV) and old residential waste collection center (group V), of Bikaner city (Rajasthan, India) was carried out from February, 2010 to May, 2010. Water samples were taken from surface only owing to low depth and investigated for various abiotic factors (viz. transparency, pH, carbonate, bicarbonate, total alkalinity, total hardness, salinity, chloride, calcium, magnesium, sulphate, nitrate, silica, and inorganic phosphorous) and biotic factors (viz. number and diversity of bacteria). The domestic sewage water causes major water borne diseases basing upon Total Bacterial Count (TBC) and coliform Count (CC). The coliform count in the present study ranged from 2.5 to 5.12 MPN/mL. Comparision of microbial population in sewage water from all different Groups was done and the higher values of TBC and CC were recorded only in Sewage treatement hub (Group III). Full article

Species composition and abundance of the phytoplankton community in Acapulco Bay, Mexico, were studied from May to December 2009. Samples were collected at 5 stations (4 coastal and one oceanic) at 3 depths (1, 5 and 10 m). Eighty-seven species were identified: 54 dinoflagellates, 32 diatoms and one silicoflagellate. The community was structured mainly by adiaphoric species, that is species adapted to both neritic and oceanic environments. Species abundance and composition varied significantly during the sampling period due to increased nutrient concentrations in the rainy season. Dinoflagellate species were more abundant during the dry season, and diatom species dominated numerically during the rainy season. Full article

The study of the prevalence of asymptomatic Plasmodium falciparum in humans infected with immunodeficiency virus (HIV) was carried out in Ile-Ife, Osun State Nigeria. The aim of the study is to determine the prevalence of asymptomatic infection P. falciparum in HIV positive individuals and correlate it to age Parasitaemia and CD4 T cell count. Out of ninety three (93) HIV positive patients that participated in the study, 53 (58.8%) were females while 40 (41.4%) were males; 48 (52.4%) females and 35 (33.8%) males were positive for asymptomatic P. falciparum given a total number of 83 (86.6%). Twenty non-HIV patients were used as control samples: 9 (45%) were males and 11 (55%) were females. With 3.0 (33.3%) males and 5 (45.45%) females were positive with insignificant value of mean Parasitaemia of 125.0 µl of blood. Age group 31-40 had the highest positive rate of 26 (32.2%) and age group 11-20 and above 60 had the least of positive rate. The correlation between age and both CD4 T cell count and Parasitaemia showed levels of significance less than 0.01 (P < 0.01) while the correlation between CD4 T cell and count and Parasitaemia showed no significant correlation, having P-value of P > 0.05. Comparing the males mean age, CD4 T cell count and Parasitaemia with that of females there was no level of significance P-value being greater than 0.05 (P > 0.05) each. In conclusion, the study showed that in asymptomatic Plasmodium falciparum, almost all the tested samples were positive which could be as a result of depletion in the immune level, hence there is need to always screen for Plasmodium falciparum whether in asymptomatic or symptomatic patients. The CD4 T cells count from the study can not be used for the detection or determination of the presence of malaria infection in HIV positive patients. The best method for malaria identification so far is still the staining method. There should not be discrimination when sampling the patient when investigations on HIV and malaria are to be carried out when both are infected. Full article