Biocontrol of fungal phytopathogens by Bacillus pumilus

Plant growth-promoting bacteria are one of the most interesting methods of controlling fungal phytopathogens. These bacteria can participate in biocontrol via a variety of mechanisms including lipopeptide production, hydrolytic enzymes (e.g., chitinase, cellulases, glucanase) production, microbial volatile organic compounds (mVOCs) production, and induced systemic resistance (ISR) triggering. Among the bacterial genera most frequently studied in this aspect are Bacillus spp. including Bacillus pumilus. Due to the range of biocontrol traits, B. pumilus is one of the most interesting members of Bacillus spp. that can be used in the biocontrol of fungal phytopathogens. So far, a number of B. pumilus strains that exhibit biocontrol properties against fungal phytopathogens have been described, e.g., B. pumilus HR10, PTB180, B. pumilus SS-10.7, B. pumilus MCB-7, B. pumilus INR7, B. pumilus SE52, SE34, SE49, B. pumilus RST25, B. pumilus JK-SX001, and B. pumilus KUDC1732. B. pumilus strains are capable of suppressing phytopathogens such as Arthrobotrys conoides, Fusarium solani, Fusarium oxysporum, Sclerotinia sclerotiorum, Rhizoctonia solani, and Fagopyrum esculentum. Importantly, B. pumilus can promote plant growth regardless of whether it alters the native microbiota or not. However, in order to increase its efficacy, research is still needed to clarify the relationship between the native microbiota and B. pumilus. Despite that, it can already be concluded that B. pumilus strains are good candidates to be environmentally friendly and commercially effective biocontrol agents.

Problems associated with vermicomposting of dog excrement in practice using Eisenia andrei

One 25-kg dog produces about 500 g of excrement per day. Excrement is a potentially hazardous material, as it may contain pathogenic microorganisms. Our samples were tested for the presence of thermotolerant coliform bacteria, Enterococcus spp., Escherichia coli and Salmonella spp., which are indicators of faecal contamination, as well as for the presence of helminths and their eggs. During the experiment, it was observed whether these microorganisms could be eliminated by vermicomposting. There were two variants of vermicomposting piles: one test pile (with continuous feeding) and one control pile (with a single feeding). The vermicomposting process was run in outdoor conditions in park for 51 weeks using Eisenia andrei earthworms. The vermicomposting of dog excrement with waste from park maintenance (1:2) can produce a good quality fertiliser. During the process of vermicomposting, there was a gradual decrease in the content of pathogenic bacteria. At the end of the vermicomposting process, there were no eggs or adult helminths. The vermicompost was very rich in microorganisms and enzymatic activity. The pH value was slightly alkaline, and the C:N ratio corresponded to value of mature vermicompost.

Safety and Accuracy of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Identification of Highly Pathogenic Organisms

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) sample preparation methods, including the direct, on-plate formic acid, and ethanol/formic acid tube extraction methods, were evaluated for their ability to render highly pathogenic organisms nonviable and safe for handling in a biosafety level 2 laboratory. Of these, the tube extraction procedure was the most successful, with none of the tested strains surviving this sample preparation method. Tube extracts from several agents of bioterrorism and their near neighbors were analyzed in an eight-laboratory study to examine the utility of the Bruker Biotyper and Vitek MS MALDI-TOF MS systems and their in vitro diagnostic (IVD), research-use-only, and Security-Relevant databases, as applicable, to accurately identify these agents. Forty-six distinct strains of Bacillus anthracis, Yersinia pestis, Francisella tularensis, Burkholderia mallei, Burkholderia pseudomallei, Clostridium botulinum, Brucella melitensis, Brucella abortus, Brucella suis, and Brucella canis were extracted and distributed to participating laboratories for analysis. A total of 35 near-neighbor isolates were also analyzed.

Bacteriological assessment of some vegetables and ready-to-eat salads in Alexandria, Egypt

BACKGROUND

Fresh vegetables and ready-to-eat salads (RTES) are essential components of human diet. Despite their benefits, they remain a major public health concern, because they have been implicated in foodborne illness outbreaks in numerous countries.

AIM

The present study aimed to assess the bacteriological quality of some fresh vegetables and RTES in Alexandria, Egypt.

MATERIALS AND METHODS

This cross-sectional study included 121 samples of vegetables and RTES that were randomly purchased from different markets, restaurants, and street vendors in three districts in Alexandria. All samples were subjected to heterotrophic plate count using pour plate method; detection and enumeration of total coliforms, fecal coliforms and Escherichia coli by multiple tube dilution method; and isolation and detection of Salmonella spp. using standard microbiological methods.

RESULTS

The aerobic colony count (ACC) for the 71 tested fresh vegetable samples ranged from 2.0 to 10.4 log CFU/g. Green pepper had the highest ACC mean value (8.4 log CFU/g), whereas lettuce showed the lowest ACC mean (5.1 log CFU/g). Fecal coliforms were detected in 90.1% of tested vegetable samples and 66% of the examined RTES samples. Of the 22 street-vended RTES samples, 18.2% were significantly unsatisfactory regarding E. coli. Salmonella spp. was not detected in any of the examined samples.

CONCLUSION

All examined samples were contaminated and yielded growth of aerobic mesophilic bacteria with varying densities. According to the Public Health Laboratories guidelines, only street-vended RTES samples yielded unsatisfactory levels of E. coli, which indicates the need for close supervision and regular inspection of hygienic practices and preparation methods of street-vended salads.

Biosafety Recommendations on the Handling of Animal Cell Cultures

The first steps in tissue culture are dating back to the beginning of the nineteenth century when biosafety measures did not yet exist. Later on, animal cell culture became essential for scientific research, diagnosis and biotechnological activities. Along with this development, biosafety concerns have emerged pointing to the risks for human health and in a lesser extent for the environment associated to the handling of animal cell cultures. The management of these risks requires a thorough risk assessment of both the cell cultures and the type of manipulation prior the start of any activity. It involves a case-by-case evaluation of both the intrinsic properties of the cell culture genetically modified or not and the probability that it may inadvertently or intentionally become infected with pathogenic micro-organisms. The latter hazard is predominant when adventitious contaminants are pathogenic or have a better capacity to persist in unfavourable conditions. Consequently, most of the containment measures primarily aim at protecting cells from adventitious contamination. Cell cultures known to harbour an infectious etiologic agent should be manipulated in compliance with containment measures recommended for the etiologic agent itself. The manipulation of cell cultures from human or primate origin necessitates the use of a type II biosafety cabinet. The scope of this chapter is to highlight aspects relevant for the risk assessment and to summarize the main biosafety recommendations and the recent technological advances allowing a mitigation of the risk for the handling of animal cell cultures.

Patterns of resistance to antibiotics at king fahd hospital of the university

INTRODUCTION AND AIM

A sharp worldwide rise in bacterial resistance to antimicrobial agents in both nosocomial and community acquired pathogens has recently been observed. This may complicate treatment of infectious disease or increase the cost of its management. It is, therefore, important to regularly investigate the patterns of resistance to antimicrobial agents at both local and national levels.

METHODS

The antibiograms of organisms isolated over a one-year period in King Fahd Hospital of the University were analyzed.

RESULTS

Of the 3679 microbial isolates of 35 types of organisms identified, the most common were Streptococcous spp (25.5%), S. aureus (16.1%), E. Coli (12.7%), Psueudomonas spp (9.3%) and Klebsiella spp (7%) High resistance rates (>50%) to ampicillin and to amoxycillin + clavulanate (AMX+CLV) were encountered in Enterobacter spp., and H. influenzae while in E. coli, the resistance was higher to ampicillin (60.0%) than to AMX+CLV (38.1%). With regard to S. aureus, 98.3%, 91.1% and 25.5% of isolates were resistant to penicillin, AMX+CLV and methicillin respectively but all were sensitive to vancomycin. High resistance (53% of 2830 isolates) to tetracycline was also observed especially in H. influenzae (80.5%), Streptococcous spp (72.9%) and E. Coli (54.5%). The same organisms were also highly resistant to trimethoprim/sulphamethoxazole with rates of 75.5%, 80.4% and 48.1% respectively. Moderate resistance (26% of 1567 isolates) to gentamicin was noted but the drug remained very effective against most tested gram-negative organisms. In addition, multiple resistance to gentamicin and AMX+CLV was also detected in 24.3% of 839 isolates.

CONCLUSIONS AND RECOMMENDATIONS

It is concluded that the alarmingly high pattern of bacterial resistance to antibiotics may reflect the extent of use of each antibiotic in the eastern province of Saudi Arabia. It is recommended that hospital antibiotic policies (purchasing, prescribing and dispensing) be based on, and regularly reviewed in accordance with hospital antibiogram results. A center for infectious disease control should also be established in each region of the Kingdom to disseminate information and coordinate antibiotic policies among hospitals.