Microbiología Médica y Diagnóstico

Metal pollution in the environment and human diet represents a perennial problem and is detrimental to human health. Developed countries are seeking ways to find a solution for this problem. However, in developing countries such as Iran largely due to the lack of appropriate infrastructures, all people are exposed to the risk of heavy metals and nobody pays due attention to this problem. Bioremediation projects, in which bacteria are used, are currently an active field to solve the problem. The present study aimed to identify bacteria that might be used for disintegration of heavy metals in foods (cow's milk) in the intestines of humans. First, the amount of mercury and lead in cow's milk was determined by atomic absorption spectrophotometry and then 25 bacterial strains from the human intestine were purified and identified. After that, MIC test was conducted on the basis of resistance against heavy metals for 25 samples. To confirm the disintegration of heavy metals, bacterial biomass was isolated, and the atomic absorptions were assessed. Finally, bacterial DNAs were extracted and sequenced. The collected milk samples were contaminated with mercury and lead and 2 out of 25 collected samples were able to disintegrate heavy metals. The DNAs for the two bacteria were isolated, sequenced, and compared with other sequences in the GeneBank. The results revealed that the two isolated bacteria were new strains of E. coli. Finally, the resulting species were labeled and registered with the name of the authors in the NCBI website. Our findings indicated that two strains of E. coli were able to disintegrate heavy metals (mercury and lead) from foodstuffs (cow milk) in the intestinal tract of humans.

Catheter-associated urinary tract infections (CAUTI) constitute about 40% of health-care associated infections in the United States. It is estimated that about 15% to 25% of hospitalized patients receive a urethral catheter at some point during hospitalization predisposing them to the development of CAUTI. Pathogenic bacteria colonize the surface of the catheter and develop highly resistant structures termed biofilms which protect them from the effects of diverse antibiotics. Escherichia coli are among the main causative agents of CAUTI. Due to the emergence of antibiotic resistant strains, it is critical to develop new novel antimicrobial agents. We recently showed that a novel anti-biofilm agent, Next Science, inhibited biofilm development by wound pathogens. In this study, we tried to determine if treating urinary tract catheters (UTC) with NS prevents the development if E. coli biofilms.

Three types of UTCs were cut into small pieces that were treated with NS. Biofilm development by an E. coli laboratory strain and several E. coli clinical isolates on treated and untreated pieces was accomplished using the microtiter plate assay. Biofilms developed on inner and outer surfaces of the catheters were quantified by determining the number of microorganisms (colony forming units) on each piece and visualized using confocal laser scanning microscopy (CLSM).

In comparison with untreated catheters, all three types of NS-treated catheters prevented biofilm development by tested E. coli strains. In addition, CLSM demonstrated the presence of E. coli biofilms on the inner and outer surfaces of the untreated but not treated catheters. Our results suggest that NS is a novel antimicrobial treatment to prevent biofilm development by pathogenic E. coli strains on UTCs.

In Argentina, conventional culture methods for the isolation of diarrheal bacteria continue to be the most widely used form of diagnosis in many clinical laboratories. In this work we validated 11 in-house real-time polymerase chain reactions (PCRs) assays for the specific and rapid detection of Salmonella spp., Shigella spp., enteroinvasive E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, Shiga toxin-producing E. coli, E. coli O157, Cronobacter sakazakii, Campylobacter jejuni, Campylobacter coli, Vibrio cholera and Clostridium difficile. The sensitivity of the assays was less than 102 CFU/ml for all the studied pathogens; selectivity and specificity were 100% in all cases and robustness was optimal. These PCR methods could be used to accurately detect the main bacterial causes of infant gastroenteritis.

An amino acid position with maximum Shannon information entropy and maximum cumulative mutual information is identified in Zika virus polyprotein. This amino acid position is used to sort the subset of Zika virus polyprotein mutations found exclusively in viruses isolated from human hosts but not from vector Aedes mosquitos. The identified mutational amino acid position is a component of a 20-mer peptide in the NS1 protein that has been reported with putative epitopic activity by Freire et al. It is suggested that the observed dual maxima bioinformatic parameters reported here for an exclusively human mutational site support the proposed function of that site in immunological activity.

Objective: Assess varying levels of leukocyte esterase presence on urine dipstick as a risk factor for positive urine culture.

Materials and methods: Retrospective evaluation of outpatient laboratory data from Beloit Memorial Hospital obtained randomly from samples in outpatient settings in the year 2016. 2000 urine results obtained from automated urine dipstick and microscopy analysis. From the 2000 samples, 1123 patients randomly selected and grouped into controls and case participants based on positive urine cultures. Information gathered included age and gender.

Conclusion: Leukocyte esterase on dipstick analysis at “large” or “moderate” levels are both independent positive predictors of positive urine culture. “Small” level of leukocyte esterase has no predictive value for positive urine culture and “trace” leukocyte level has a negative predictive value for a positive urine culture.

Background: Rabies is acute fatal encephalitis that affects all mammals and is a worldwide zoonotic disease caused by rabies virus. Knowledge, Attitudes and Practice (KAP) of the community on rabies is vital to prevent the neglected deadly disease. The aim of the study was to assess the KAP of the community on rabies in and around Ambo town, Ethiopia.

Methods: A cross sectional and retrospective studies were conducted from November 2015-April 2016 in and around Ambo town to assess knowledge, attitude and practice (KAP) of community on rabies; and to know a oneyear status of human rabies suspected case in Ambo hospital. The study participants were enrolled consecutively, and data was collected using questionnaires. Data was cleaned, coded and entered for analysis by SPSS version 20 software. KAP were defined based on mean scores.

Results: The questioners survey indicated that the communities had poor knowledge, good attitude and good practice with (46.1%), (50.5%) and (63.5%), respectively. Hence the overall KAP scores were good (53.4%) implying that the communities had good awareness about rabies. There was no statically significant association between sex and age of respondents with knowledge, attitude and practice scores (p>0.05). There was statistically significant association between educational level with knowledge and attitude scores (p<0.05). The retrospective review showed that the majority of suspected cases were males (52.4%). Almost all suspected cases were bitten by dog (94.2%) followed by human bites (3.8%). Majority of suspected case were recorded in autumn and winter (35.6%).

Conclusion: This study showed that there was terrestrial rabies (human, canine, sylvatic) that leads to human rabies suspected case and awareness of respondents on rabies were good although poor about wound management for bitten individuals in the study areas. Further public awareness creation is still essential on multidimensional impacts of rabies, responsible pet ownership, managements of bitten animals, first aid treatment and on the use of traditional remedy.

Mastitis is an inflammation of the mammary gland caused by pathogenic microorganism, occurs in all mammalian species but particularly important in dairy cattle. A cross sectional study design was conducted from June 2015 to September 2015 to screening bovine mastitis in randomly selected dairy farms in and around D/Tsige town. About 384 (118 cross, 153 Exotic, 113 local breed) of lactating cows were included in the study. Prevalence of the clinical mastitis was determined through examination of abnormalities of milk and udder of cows; and California mastitis test to diagnose sub-clinical mastitis. The overall prevalence of clinical mastitis was 9.64% and 9.63% at cow and quarter level respectively. Of the 1536 quarters examined, prevalence of clinical mastitis, sub clinical mastitis and blind quarters (non-functional teats) were found to be 9.63%, 33.85% and 1.2%, respectively. On cow basis, out of 384 lactating cows, 167 (43.49%) cows had abnormalities in their udder, teats and milk as evidence of clinical mastitis. The prevalence of mastitis at cow level was higher in exotic breeds (39.8%) and those were found in late lactation stage (42.2%), parity number was found to be statistically significant (P<0.05). In the present study, there was high prevalence of sub clinical mastitis that result losing of milk production and cause economic lose to the dairy farm. In view of this, the routine test of dairy cows, and preventive and control measures are recommended to reduce the prevalence of clinical and sub clinical mastitis in dairy farms in and around D/Tsige town.

Identifying the causative pathogens in patients with pyogenic vertebral osteomyelitis is important for optimizing antibiotic therapy. Thus, we examined patient characteristics and investigated the efficacy of the combined use of blood culture and image-guided biopsy culture for identifying the causative pathogens of pyogenic vertebral osteomyelitis. A case series study was conducted in hospitalized patients who were diagnosed with pyogenic vertebral osteomyelitis using electronic medical records. Twenty-three patients who had undergone both blood culture and image-guided biopsy to determine the causative pathogens were identified. Detailed patient characteristics were identified, and the detection rate of a causative pathogen was 57% using either blood or biopsy specimen culture. By combining the results of each culture, the detection rate was increased to 83%. We described the detailed characteristics of patients with pyogenic vertebral osteomyelitis from whom both blood and biopsy specimen cultures were obtained. We found that the combined use of blood culture and biopsy specimen culture is useful for enhancing the detection of causative pathogens in patients with pyogenic vertebral osteomyelitis.