Medical Microbiology & Diagnosis

Introduction: In malaria diagnosis, a highly sensitive and specific test will ensure appropriate administration of antimalarial treatment, hence promoting a parasite-based diagnosis as recommended by the World Health Organization (WHO). The Global Malaria Program recommends that suspected clinical malaria could be confirmed using the quality assured Rapid Diagnostic Test (RDT) and microscopy diagnostic tools. This study was designed to assess the performance of Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP2-RDT), with respect to age and parasite density.
Methodology: This study was carried out in the Bamenda Regional Hospital Laboratory, with 381 patients enrolled into the study by convenient sampling technique. A simple questionnaire, microscopy and PfHRP2-RDT techniques were used to collect data on sex, age, and malaria status of the study participants. Both descriptive statistics and analysis of variance were used for data analysis.
Results: Results by microscopy show that up to 68.55% (109/159) of the males and 41.89% (93/222) of the females were infected. About 55.44% of those infected were younger children (≤ 5 yrs) and young adults (˃18 yrs to ≤ 35 yrs), with up to 68.81% of the infections being mild parasitemia. Results by microscopy and PfHRP2-RDT were not the same, and the difference between the daily variation in test results was significant at P=0.0012. With microscopy as the standard, the sensitivity, specificity, positive predictive value and negative predictive value of PfHRP2-RDT were; 100%, 92.75%, 94.26% and 100% respectively.
Conclusion: The microscopy technique indicated low specificity and positive predictive values. Hence, in order to ensure an effective parasite-based malaria diagnosis, a microscopy confirmatory test is recommended for every PfHRP2-RDT positive result.

Background: Scientists and Manufactures are working closely in order to develop new tools and strategies that can fight resistant malaria vectors more efficiently. Sumitomo chemicals of Japan a company with a long history of production of long-lasting insecticides treated nets (LLINs); Olyset® nets have developed Olyset® Plus, which has synergy- piperonyl butoxide (PBO). It is anticipated while PBO is not an insecticide; it will enhance the knockdown effect of permethrin on olyset net thus killing mosquitoes with metabolic resistance mechanism. The study aimed at evaluating efficacy trial of new pest control product: Olyset® Plus-long lasting insecticide treated net with added synergist (piperonyl butoxide) for malaria vector control in Kenya.
Methodology: We evaluated the knockdown and killing effect of Olyset® Plus net compared to Olyset® net which is within the Kenyan market using field collected mosquitoes.
Results: The Olyset® Plus nets showed 100% mosquito knockdown indicating good performance compared to Olyset® a locally marketed LLINs which had 95%. Permethrin-treated net with PBO was found to be more effective against mosquitoes, retains acceptable mosquito killing effect after several washes.
Conclusion: Olyset® Plus nets are recommended for registration and use in Kenya as an LLINs against mosquito vectors of malaria if it meets all other requirements of Pest Control Products Board.

Background: Malaria interventions particularly malaria vector control has gained popularity within the last twenty years. Sumitomo Chemical Company has developed a larvicide, Sumilarv 0.5G, based on the insect growth regulator -pyriproxyfen. SumiLarv 0.5G, unlike other larvicides, it has a novel mode of action and does not kill the larvae but prevents the emergence of adults by affecting the development of the larval and pupal stages. The study aimed at evaluating efficacy of Sumilarv 0.5G, an insect growth regulator - pyriproxyfen, against mosquito larvae in Kenya.
Methodology: Laboratory and field trials were carried out to determine the efficacy and residue effect of Sumilarv 0.5G against all mosquito species for the purpose of registration and use of this product in Kenya.
Results: Dosage of 2 g per 1000 liters of water was found to be effective in preventing adult mosquito emergence. The concentration of 2 g per 1000 liters measured as one teaspoonful was found to prevent re-infestation of the water by mosquitoes for a period of three months.
Conclusion: Sumilarv is recommended as a larvicide for the control of mosquito larvae and pupa if applied at above concentrations.

In this era of instrumentation, and lab automation, there is great improvement in the isolation and identification of microbes associated with various infectious diseases. The cause of concern is the fact that, not all microorganisms isolated from the human clinical specimens are the pathogens. Also, there are areas in human body which are normally colonized by bacteria, which are commonly termed as commensals. Isolation of such organisms from the patients with signs of infections, and to confirm their role as a pathogen appears be difficult. Therefore, it is important to understand the normal microbial flora and its changes before and after the signs of infection. Vaginal environment is known to be colonized with Lactobacilli, which is responsible for the acidic nature, and the reason for resistance against other infections. But several studies have demonstrated the presence of other bacterial flora that include Gardnerella vaginalis (G. vaginalis), both in the absence as well as during infection/inflammation. Several other reports have noted the presence of G. vaginalis associated with infections including the urinary tract infections. This review attempts to evaluate the potential role of G. vaginalis in human infections, and its clinical significance when isolated from human clinical samples.

Objective: To compare the performance of Caspofungin with the conventional antifungal drugs on the Candida albicans isolates.
Materials and methods: Cases and Samples: The present study was carried out in the Department of Microbiology J. N. Medical College, AMU. Total of 6000 patients included in the study. Samples were collected according to their clinical presentation.
Materials and methods: Cases and Samples: The present study was carried out in the Department of Microbiology J. N. Medical College, AMU. Total of 6000 patients included in the study. Samples were collected according to their clinical presentation.
Evaluation and comparision of antifungal activity of Caspofungin: a. Disc diffusion, and b. Broth mico dilution method.
Results: The susceptibility testing of Caspofungin and other conventional antifungal agents by broth dilution method revealed very low MIC of Caspofungin (0.062-1 μg/ml) as compared to fluconazole (1-64 μg/ml). Thus, Caspofungin proved to be more potent than other antifungals in vitro.
Conclusion: We found Caspofungin to be more potent on the resistant isolates of Candida albicans in vitro.

Aspergillus is a mould which may lead to a variety of infectious, allergic diseases depending on the immune status or pulmonary structure of the host. Invasive pulmonary aspergillosis occurs primarily in patients with severe immunodeficiency. Early and rapid diagnosis of systemic fungal infections remain limited, despite intensive efforts by many investigators. Few clinical guidelines have been previously proposed for either diagnosis or management of Pulmonary Aspergillosis. The current study was undertaken for comparing various detection methods like conventional direct microscopy or histopathology, culture methods, immunological (GM ELISA) and molecular methods (PCR). To identify carcinoma cell types and to categorize Aspergillosis types histopathology was done. For direct fungal examination, culture, Aspergillus polymerase chain reaction (PCR), and galactomannan (GM) detection, bronchoalveolar lavage (BAL) fluids were collected. In this study microscopy was found to have low sensitivity of (70.5%) while culture had highest specificity (97.6%). GM assay showed a sensitivity of 100% and a specificity of 86.4% whereas PCR has an overall sensitivity of 100% and a specificity of 81.3%. Thus, we suggest that both BAL PCR and GM ELISA may be beneficial for use in early diagnosis of Aspergillosis, especially those patients who do not demonstrate radiological signs.

Immunodominant antigens represent a potential tool to develop serological diagnosis in bovine tuberculosis (bTB). Novel antigens from natural acquired Mycobacterium bovis from aerosol infected animals have been identified. However, still it is necessary to define antigen recognition directly from the cattle. Herein, we are reporting an evaluation of M. bovis strains isolated from cattle in Mexico using tubercle bacilli cell growth for serum reactivity and antigen production kinetics (7-21 days). During early, middle and longtime cell growth, we found that there are a set of proteins that in comparison with BCG antigens, mostly reacted toward either pooled or individual serum positive samples obtained directly from animals infected with M. bovis. Interestingly, we found that antigens of 45, 48, 75 and 90 KDa produced at 7 or 21 days are mostly recognized by the serum of infected cattle TST(+) vs. uninfected (TST-). Altogether, the data reported here indicate that in addition to the cell wall factor virulence factors; the antigens mostly recognized and produced during the growth of tubercle bacilli could strengthen diagnostic tests in cattle while discarding BCG cross reactivity.

Objective: The aim of this study is to find if Viral Lower Respiratory Tract Infections (V-LRTI) occurs more common on top of existing Chronic Lung Diseases (CLD) or has no relation. The study also aimed to learn about the clinical presentation V-LRTI in young children in Jeddah.
Materials and methods: This was a retrospective study of 136 young patients of 5 years or less who were presented to the department of pediatrics at doctor Soliman Fakeeh hospital, Jeddah. The children diagnosed primarily as LRTI were enrolled in the acute phase and through the chronic stage of the disease. Dr. Soliman Fakeeh Hospital is a private (tertiary care) hospital uniquely located to serve a wide catch population from South and North Districts of Jeddah. A database was developed to provide the information about preliminary diagnosis, clinical examination, laboratory investigations, treatment and final diagnosis. Among the 136 patients, seven patients were lost to follow up and hence, excluded from analysis. Nasopharyngeal Aspirate (NPA) test type was done to identify causative viral infection. End-point was calculated as per protocol on 129 patients.
Results: A total number of 34 patients out of 129 had positive NPA Viral Test (26%); 19 patients out of the 34 (56%) had CLD and 15 patients (44%) had no CLD. On the other side, 95 patients out of 129 had negative NPA Viral Test (74%); 59 patients out of the 95 (62%) had CLD and 36 patients (38%) had no CLD. The results are not significant (p-value=0.524). We concluded that there is no significant difference between occurrences of V-LRTI on top of existing CLD. Results show that there is significant difference between V-LRTI and non-V-LRTI presence in the following variables (p-value<0.05): In V-RTIs; Age at time of diagnosis is less (0.36+0.31 vs 0.79+0.07), admission to hospital is more (91.2% vs 55.8%), oxygen saturation is less (92.50+3.72 vs 95.96+0.57), Crackles is more (65.6% vs 40%.0%) Wheezing is more (71.9% vs 43.2%), Dyspnea is more (44.1% vs 9.5%) and Diarrhea is more (5.9% Vs 0.0%).
Conclusion: The study shows that V-LRTI constitutes (27%) with RSV being the commonest causative virus (79.4%). V-LRTI statistically occurs in younger age with more hospitalization. Dyspnea, crackles and wheezing are statistically more frequent in V-LRTI with less Oxygen saturation than Non-V-LRTI. CLD is not a predisposing factor in V-LRTI in preschool age.

Background: Intestinal parasitic Infections (IPI’S) are major health problem in most parts of the world; especially in the under developed and developing countries. Giardia lamblia, Entamoeba histolytica, Ascaris lumbricoides and hookworm are commonly encountered parasites. The study was planned to estimate the proportion of IPI’s in patients of pediatric age group and do a comparative evaluation of ELISA and Microscopy for Giardia.
Materials and methods: Stool samples were taken from 200 patients of pediatric age group with the given inclusion criteria, during August 2017 to July 2018. Microscopy, formalin ethyl acetate concentration method and ELISA for Giardia was performed.
Results: The prevalence of intestinal parasitic infections in our study was found to be 28%. The most common pathogenic parasite was found to be Giardia lamblia (19.5%) followed by Entamoeba histolytica (4.5%). In our study, stool samples positive by Microscopy and formalin ethyl acetate concentration were 8% and 15%. ELISA and Rapid kit test were found to detect higher proportion of Giardia as compared to Formalin ethyl acetate concentration method and Microscopy (Saline and Iodine mount).
Conclusion: The prevalence of intestinal parasitic infections in our study was 28%. The most common parasite was Giardia lamblia followed by Entamoeba histolytica. The study showed that parasitic infections were common in patients of uneducated families. Patients who did not wash their hands with soap and water before meals and after using toilet were at increased risk.

Vibrio alginolyticus is rarely reported as a human pathogen. However, we report two cases from Spain. The first case involved a 69-year-old male with a rectum adenocarcinoma that developed enterocolitis and septic shock. The second case was associated with a previously healthy 37-year-old male patient with a pretibial ulcer exposed to the Mediterranean Sea. The isolates were identified as V. alginolyticus by MALDI-TOF MS and rpoD gene sequencing. The strain from the first patient was incorrectly attributed to Aeromonas sp. in the preliminary identification by API 20E and API 20NE. The antibiotic susceptibility against 13 antibiotics was tested and both strains were resistant to penicillin and ampicillin. This study is intended to raise awareness about the increasing incidence of V. alginolyticus and to that aim a review of the previous cases is also provided. Additionally, this study alerts that V. alginolyticus can be confused with Aeromonas based on the used identification method.