Journal of Medical Microbiology and Infectious Diseases
Volume:2 Issue: 1, Winter 2014

Rabies is a disease that has been known since antiquity. It is a highly fatal acute disease of the central nervous system caused by a lyssavirus. Prior to the discovery of the rabies vaccine, rabies-infected individuals fell victim to the delusions and superstitions associated with this disease. Though it has been neglected in many regions of the world, rabies remains one of the most feared diseases in many developing countries, where it takes the majority of its victims. The virus circulates mainly in domestic and wild carnivores, taking 60,000 human lives worldwide every year and inflicting significant financial damage. It can, however, be well controlled due to the availability of effective Post-Exposure Prophylaxis (PEP) protocols. Pasteur Institute of Iran has had a significant role in the establishment of current PEP protocols in the world. In spite of the availability of effective PEP protocols, preventive vaccination would be preferable in endemic regions. Annually, a considerable number of exposures to animal bites occur in Iran. The current situation in the country is well-controlled by virtue of a robust surveillance system and efficient PEP treatments, resulting in considerably low death incidences from rabies. High quality vaccines recommended by the World Health Organization (WHO) are expensive and unaffordable in developing countries, where the need for rabies vaccination is greatest. Therefore, there is an increasing need to develop new cost-effective and efficient vaccines requiring fewer injections and providing longer-lasting immunity.

The features of Helicobacter pylori adhesins, their interactions with their host counterparts, regulated and selective gene expressions are amongst the many clever strategies this microorganism undertakes to survive the otherwise sterile gastric milieu. The ingenious crafting of these interactions and the respective host reactions govern, in part, an array of consequences ranging from asymptomatic infections to varying degrees of gastric inflammation, ulcer formation, atrophic, metaplastic and dysplastic changes and ultimately gastric cancer. The most well studied H. pylori adhesins include those which bind host blood group antigens; namely BabA and SabA. In this review, I attempt to tell the historical tale of how these moieties and their respective interactions with the host were discovered and characterized. The details of the subsequent applications of these findings in further genotyping studies will be later reviewed to avoid disruption of this crafty tale.

Toxoplasmosis, caused by Toxoplasma gondii, is a protozoan parasitic infection distributed worldwide. Early infection by this protozoa can lead to abortion and congenital toxoplasmosis in pregnant women. This study was conducted to determine the seroprevalence of T. gondii infection among pregnant women referring to Shahid Akbar Abadi Hospital, Tehran, Iran during 2010-2013. This descriptive study carried-out from October 2010 to March 2013. The blood samples from 785 pregnant women were collected and examined for specific IgG and IgM antibodies to T. gondii by ELISA method. From 785 sera samples tested 541 (68.9%) were negative for any anti- T. gondii antibody. The women with anti- T. gondii positive and borderline IgG titers comprised 31.1% of the population study. T. gondii specific IgM was negative for all the pregnant women examined, and only for 6 women the titer showed to be at borderline. The rate of infection increased with age, as the highest rate of seropositivity (42.2%) was observed in 35-50 age group. However, no significant difference in the seroprevalence of T. gondii infection was observed between different age groups (P = 0.139). As a considerable number of the pregnant women were negative for T. gondii antibodies and are prone to acquisition of acute T. gondii infection over the course of pregnancy, primary prevention measures and serological monitoring of seronegative pregnant women are important for preventing congenital toxoplasmosis.

The decreased level of immunity in Human Immunodeficiency Virus (HIV) infected patients increases their vulnerability to various opportunistic fungal infections. Oral candidiasis has been found to be the most common fungal infection among HIV infected patients. The present study was conducted to evaluate the spectrum of various opportunistic fungal infections and their correlation with CD4+ counts. A total of 163 clinically suspected cases of fungal infections with HIV seropositive status were studied. The most common infections observed were oropharyngeal candidiasis (39.26%) followed by cryptococcal meningitis (6.74%). The study showed opportunistic fungal infections in 46.6% of HIV infected patients with CD4+ counts ≤200 cell/ µl. Early diagnosis and prompt antifungal treatment is necessary to decrease the morbidity and mortality associated with the infections to increase the survival of HIV infected patients.

Haemophilus influenzae is a gram-negative bacterium causing a variety of respiratory infections in developing countries, especially in children. Nasopharynx carriers of H. influenzae are the prominent source and transitional vectors of invasive diseases. As very limited information on H. influenzae carriage rate in Iran was available, an evaluation on prevalence of this bacterium in children ≤ 6 years old seems crucial. Totally 533 mucus samples were collected using nasopharyngeal swabs from children ≤ 6 years old who lived in 4 nursery centers in Tehran or refereed to the Children''s Medical Center of Tehran, Iran, from August 2011 to October 2012. The samples were transported in Stuart transport medium to the Microbiology Laboratory of Pasteur Institute Tehran, Iran, and were cultured on chocolate agar containing bacitracin antibiotic. The initial diagnosis for detection of H. influenzae was performed by standard biochemical tests, and confirmation was achieved by PCR assay targeting outer membrane protein (omp) P6 gene. Based on primary cultures and biochemical tests, out of 533 samples, 182 (33%) showed to be H. influenzae positive, but PCR assay confirmed presence of H. influenzae in 153 (28%) isolates; 56(37%) belonged to girls and 97 (63%) to boys. The prevalence of H. influenzae in three different age groups: ≤ 24, 25-48, and 49-72 month-old children were 31 (20%), 69 (45%), and 53 (35%), respectively. Our results showed a high rate of H. influenzae carriers among children ≤ 6 years old, which is similar to those of other unvaccinated countries. H. influenzae carriage rate was associated to age and respiratory infection diseases. The children aged 25-48 months showed a higher rate and the rate reduced with increase in age. Further investigation including molecular studies is required to obtain the carriage rate throughout the country.

This study was aimed to investigate the effects of risk factors, and environmental and climatic factors a ffecting the occurrence of Crimean-Congo hemorrhagic fever (CCHF) in Iran. We used temporal modeling to predict the future occurrence of the disease in the country. We analyzed the data of 165 CCHF patients from all over Iran (e xcept the districts Zabol and Zahedan in Eastern Iran) during 2000 to 2006. In this study, 130 districts with at least one reported case patient, and 780 districts with no reported case patient, as the control group, were included in the model. Logistic regression was used to design the temporal model of the disease at the district-month level nationwide with the purpose of predicting the occurrence of CCHF disease with in one month in a district. The designed model indicated that the history of previous reports of the disease in a district increased the risk of further reports of the disease (odds ratio: 2.53 (95% CI: 1.61, 3.97), (P <0.001)). Moreover, w ith each one-million increase in the urban population, the odds of a report of the disease increased 20% (P =0.003). The odds of the occurrence of the disease were reduced by 9% w ith the increase in e ach degree of latitude (P =0.028). The odds of the occurrence of the disease increased 6.25 times w ith the increase in e ach kilometer of altitude (P <0.001). T he disease had a decreasing s ecular trend so that the occurrence of the disease was reduced by 10 % each year (P =0.008). Our findings showed that based on the history of CCHF in districts, and population and geographical features, hot zones may be defined with some acceptable accuracy.

The innate immune system as the first line of defense against the pathogens recognizes pathogen-associated molecular patterns (PAMPs) by Toll-Like Receptors (TLRs). Interaction of bacterial PAMPs by TLRs results in activation of innate and acquired immunity. FimH adhesin, a minor component of type 1 fimbriae encoded by Uropathogenic Escherichia coli (UPEC) is a PAMP of TLR4 that stimulates the innate immunity against infections. The FimH involves N-terminal and C-terminal domains. Detailed information about the TLR4 interaction with FimH is lacking. In this study, we evaluated interaction between TLR4 and whole FimH and two domains of FimH using computational methods. Two truncated forms of FimH that included N- terminal and C- terminal truncated forms were selected from PDB. Molecular docking analysis of TLR4 against FimH was done using HEX docking tool. The molecular interaction plot between TLR4 and FimH was generated Dimplot in LIGPLOT software (v. 4.5.3). Based on the total free energy, C- terminal truncated form had the best interaction tendency to the receptor. Dimplot analysis showed that there are 11 intermolecular hydrogen bonds in the TLR4 and C- terminal truncated form of FimH complex. The high affinity of C- terminal truncated form to TLR4 suggests that this portion of FimH has important effect on the adjuvant activity and innate immune response and could utilize as adjuvant for vaccine application against microbial infections and cancers.

Toxoplasmosis is a parasitic infection caused by the protozoan Toxoplasma gondii; it leads to serious medical problems in congenitally-infected and immunocompromised individuals, while it is quite harmless in immunocompetent individuals. Toxoplasma tissue cyst matrix protein (MAG1) induces early humoral and cell-mediated immune responses. Previous studies suggested recombinant MAG1 as a promising antigen for serodiagnosis of Toxoplasma infection. A DNA fragment encoding mag1, comprising amino acids 50 to 207, was amplified from T. gondii RH strain and cloned in prokaryotic expression plasmid pET-15b(+). The cloned DNA fragment was sequenced and showed 100% similarity with the published sequences available in GenBank Database. Recombinant MAG1 was expressed in Escherichia coli, and was highly purified in a single step by immobilized metal ion affinity chromatography. In Western blot analysis, purified protein showed a much stronger reactivity with sera from patients with acute Toxoplasma infection, compared to those with chronic infection. MAG1 protein, in combination with other acute-phase markers might be useful in discriminating acute/reactivated Toxoplasma infections from chronic forms.