Bacteriological profile of wound infections and antimicrobial resistance in selected gram-negative bacteria

Background: Managing wound infections is a challenging task. Understanding their resistance pattern is an essential step at reducing its burden in hospital settings. Objective: To determine the bacteriological diversity of wound infections and the antimicrobial resistance exhibited by a selected Gram-negative bacterium in the Aljouf region of Saudi Arabia. Methods: The study retrospectively analysed the antibiograms of wound infections from hospitalized patients for the year 2019. The European Centre for Disease Control guidelines were adopted for the classification of resistant bacteria. Multidrug-, extensive drug-, and carbapenem-resistant isolates are presented as frequencies and percentages. Results: A total of 295 non-duplicate wound swab antibiograms were retrieved, 64.4% (190) and 35.6% (105) isolates were Gram-negative and Gram-positive bacterial infections respectively. Predominant pathogens included Staphylococcus species 21.0% (62), E. coli 16.3% (48) and K. pneumoniae 13.5% (40). 148 (77.9%), 42 (22.1%) and 43 (22.6%) of the Gram-negative isolates were multidrug-, extensively drug- and carbapenem-resistant. The antibiotic resistance exhibited by gram-negative bacteria was 43.4% (234/539), 59.1% (224/379) and 53.7% (101/188) towards carbapenems, 3rd - and 4th – generation cephalosporins. Conclusions: The majority of wound infections are caused by multidrug-, extensively drug- and carbapenem-resistant Gram-negative bacteria. Further studies should focus on the molecular basis of this resistance. Keywords: Wound infections; hospital; Gram-negative bacteria; antibiograms; multidrug-resistance; E. coli

ISOLATION AND PHENOTYPIC CHARACTERIZATION OF MODERATE HALOPHILIC BACTERIA FROM ATHALOSALINE LAKE, DUMAT AL-JANDAL, IN EXTREME NORTH OF AL JOUF (KSA)

Introduction: Hypersaline intra-continental (athalassohaline) salt lakes represent an extreme type of habitat where halophilic prokaryotes are a dominant form of life. Bacteria are commonly found in natural environments containing significant concentration of NaCl. Dumat Al Jandal artificial Lake is a man-made water body located in Dumat Al Jandal, Al-Jouf province. This lake features numerous ecosystems including hypersaline environments in which microbial diversity has never yet been studied. Objective: We evaluate the presence of moderately halophilic microbial population in the lake extreme environments based on Physiochemical and Microbiological characterization. Methodology: Water samples were collected from the lake from different sites. Sample salinity was determined using a conductivity meter. Samples were diluted and cultured on a chemically defined medium (CDM) to grow halophilic bacteria. The density of halophiles was estimated by viable plate counts. A collection of isolates was selected, gram-stained, tested for catalase, and characterized using standard microbiological methods. Result: Growth occurred at 3-15%(W/V), NaCl (optimum 8%), pH 5– 9(optimum 7.5) and temperature 35-40oC(optimum 38oC). The density of halophilic bacteria in water samples ranged from 2.2×102 - 42×102 colony forming units per ml (cfu ml-1). Phenotypic results revealed members of the domain Bacteria only and the predominant genus were Halomonas and Bacillus followed by others. The majority of bacteria isolated were gramnegative, catalase-positive, and rods. Conclusion: Our trials paved an effective avenue of isolating moderate halophilic bacteria from this lake in order to promote saline-alkali soil-based agriculture, and it also serves as a source for halostable enzymes which offers potential applications in various pharmacochemical industries