BackgroundThe selection of an appropriate antimicrobial is a challenging task for clinicians. The Kirby-Bauer disk diffusion method is one of the most widely practiced antimicrobial susceptibility tests (AST). It is affected by many factors among which are the media used. Mueller-Hinton agar (MHA) is the standard medium recommended in guidelines. However, these guidelines are not strictly adhered to in some developing countries.ObjectivesValidation of AST results on nutrient agar (NA) medium used as a substitute for MHA by some microbiology laboratories in Alexandria, Egypt.MethodsA total of 149 clinical bacterial isolates and 3 reference strains: Staphylococcus aureus (S. aureus) ATCC® 25923, Escherichia coli (E. coli) ATCC®25922, and Pseudomonas aeruginosa (P. aeruginosa) ATCC®27853 were comparatively challenged to antibiotics employing MHA and NA.ResultsAll antibiotics-reference bacterial strain challenges on NA compared to MHA were unacceptable (> 3 out of limit zones in 30 consecutive days). Considering clinical isolates, the frequency of very major, major, and minor errors on NA was highest in the case of P. aeruginosa (8.98%, 4.08%, and 14.7% respectively) followed by S. aureus (7.6%, 6%, and 8.8% respectively). On the other hand, the least frequency of errors was in the case of Enterobacteriaceae (0%, 0.4%, and 3.2% respectively).Conclusions and recommendationsUsing NA in AST resulted in multiple errors and the high discrepancy in results compared to MHA making it unreliable for susceptibility testing. MHA should not be replaced by NA in AST. Following guidelines and QC measures for AST must be neither bypassed nor underestimated.

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The distribution of Toxoplasma gondii genotypes varies from one geographic area to another. The present study aimed to determine T. gondii genotypes associated with human infection in Egypt. Individuals seropositive for anti-toxoplasma IgG and IgM (group I, n = 50) or for specific IgG only (group II, n = 50) were enrolled. Of the participants, 75 % were asymptomatic pregnant women. The others presented with lymphadenitis (n = 21), chorioretinitis (n = 3), and unexplained hepatomegaly (n = 1). Using nested PCR, T. gondii GRA6-coding fragment was amplified from DNA extracted from blood samples of participants. Amplification was successful in 12 samples with nonsignificant difference between both groups but with a significant association with the presence of toxoplasmosis-related manifestations. Restriction fragment length polymorphism analysis of these samples revealed the presence of type I in seven samples and atypical types in five samples. Both typical and atypical strains were detected in individuals of both groups with no bias towards specific clinical presentation.

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Long-term endotoxin challenge may promote frequent complications in dialysis patients, namely malnutrition, chronic inflammation, and atherosclerosis, which are recognized as the so-called MIA syndrome. Circulating soluble vascular cell adhesion molecule-1 (sVCAM-1) levels may be used to determine the stage of atherosclerosis. This study aimed to assess endotoxin level in hemodialysis (HD) patients and its role in inducing inflammation. The study was conducted on 50 HD patients, chosen from four dialysis centers in Alexandria. Serum blood samples were collected for the determination of albumin and C-reactive protein (CRP), and whole blood samples were used for the measurement of hemoglobin level. A heparinized whole blood sample was taken postdialysis for endotoxin assay by limulus amebocyte lysate test, and in addition to sVCAM-1 was estimated using enzyme-linked immunosorbent assay. The mean endotoxin level was 76.30 pg/mL;80% exhibited values higher than 60 pg/mL. Half the studied patients had CRP values that exceeded the upper limit of the laboratory reference range (<6.0 mg/L). A statistically significant correlation was found between endotoxin and CRP levels (r = 0.47, P = 0.001). The mean pre-HD level of VCAM was 1851.00 ng/mL, while the mean post-HD level was 2829.00 ng/mL with statistically significant correlation (r = 0.354, P = 0.012) and it also correlated significantly with endotoxin as well as CRP levels. Endotoxemia may play an important role in the aggravation of endothelial dysfunction in HD patients as indicated by the post-HD rise in sVCAM-1.

Swimming pools have been identified as posing some public health risks to users due to either bacterial or chemical contamination. As a result, maintaining good swimming pool water quality is an important issue in preventing health risks for bathers. This study aimed to evaluate the bacteriological quality of some swimming pools in Alexandria and to investigate the prevalence of Staphylococcus aureus (S. aureus) in water samples. A total of 120 water samples from 10 swimming pools were collected. Bacteriological analysis included heterotrophic plate count (HPC) using pour plate method; enumeration of total coliforms (TC), Escherichia coli (E. coli) and S. aureus by membrane filtration technique. Antimicrobial susceptibility testing was performed on isolated S. aureus. Residual chlorine and pH were measured at swimming pools side. HPC was the least complying microbial parameter, followed by TC. S. aureus was recovered from 18 samples; 9 isolates were methicillin resistant S.aureus (MRSA), compared to E. coli that was detected in 7 samples. HPC and TC showed statistically significant correlations with all investigated parameters. In conclusion, the examined pools showed poor quality regarding all examined parameters collectively according to the Egyptian guidelines, which necessitates implementation of proper measures to ensure safer environment in swimming pools.

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Acinetobacter baumannii (A. baumannii) is recognized as a major pathogen causing nosocomial infections, particularly in patients admitted to intensive care units (ICU), and many widespread strains are resistant to almost all antibiotics currently in use. Carbapenemases belonging to molecular class D (OXA enzymes) have emerged globally as the main mechanism responsible for this resistance. This work aimed at detecting the spread of OXA carbapenemases in A. baumannii in ICU patients and to identify the susceptibility patterns of strains to polymyxin E (colistin), polymyxin B, and tigecycline as a promising option for treatment. Twenty seven clinical isolates of A. baumannii, collected from Alexandria Main University Hospital, were included in this study. A. baumannii was isolated from different clinical samples from ICU patients. All 27 isolates were subjected to complete identification and antimicrobial susceptibility testing. The identified carbapenem resistant A. baumannii strains were tested for the presence of bla OXA-23, blaOXA-24, blaOXA-58 and blaOXA-51 genes using multiplex PCR assay. Colistin and polymyxin B were found to be active upon the majority of identified resistant A. baumannii strains, where around 70% of the strains were sensitive to both of them, while tigecycline was found to be more effective as 92.5% of strains were sensitive to it. Resistance to carbapenems was mediated by both OXA-51 (100%) and OXA-23 (92.5%) for the tested A. baumannii strains.