Rapid detection of methicillin resistant staphylococcus aureus bacteraemia in bactec blood culture bottles of ICU patients

Methicillin resistance and infections caused by methicillin-resistant Staphylococcus aureus [MRSA] represent a growing problem and a challenge for health-care institutions. Resistance to methicillin is primarily associated with acquisition of mecA gene. The aim of the current study was to find out the incidence of MRSA bacteraemia among ICU bacteraemic patients and evaluate direct mecA gene detection from blood culture bottles and the oxacillin [methicillin] disk diffusion method commonly used in hospitals to identify MRSA using PCR for mecA detection in isolates as the golden. The study was conducted on 300 ICU patients with pyrexia of unknown origin. Blood samples were collected under complete aseptic precautions for blood culture onto BACTEC blood culture bottles. Detection of mecA gene by Polymerase Chain Reaction [PCR] was carried directly on any bottle showing Gram-positive cocci in clusters in film. Isolates of all positive blood culture bottles were identified. For Staph aureus isolates oxacillin disk diffusion and mecA gene detection was carried. Out of 300 samples included in the study, 190 [63.3%] yielded growth. Methicillin resistant Staph aureus was isolated from 88/190 patients [46.3%]. The agreement between the results of mecA gene detection among isolates and those among blood culture bottles was found to be 100% [Kappa = 1] and the sensitivity 100%. Disk diffusion method detected 79 cases out of the 88 MRSA strains The agreement between the results of oxacillin disk diffusion sensitivity method and mecA detection either in isolates or blood culture bottles was found to be 94% [Kappa= 0.87] and the sensitivity was 89. 8%.Methicillin resistant Staph. aureus bacteraemia is a major problem in ICU. Detection of mecA gene by PCR from blood culture bottles is a good tool for rapid detection of methicillin resistance in staph aureus bacteremia. To confirm the specificity of this test, more samples from patients with Enterococcus and Streptococcus species bacteraemias need to be studied

Multi-drug resistant pseudomonas aeruginosa as a cause of chronicity in ear infections

Pseudomonas aeruginosa is the most commonly recovered organism from chronic suppurative otitis media [CSOM]. P. aeruginosa has high intrinsic resistance to many antibiotics, and this situation is worsened in infections caused by strains acquiring additional multi-resistance. The aim of this work was to assess the role of P. aeruginosa in the chronicity of ear infection. Routine basic and enriched media [nutrient agar and blood agar] were used as well as P. aeruginosa selective agar [PASA] for isolation. Two pigment enhancer media were used for differentiation: Kings A agar and Kings B agar. The anti-microbial resistance patterns of isolated P. aeruginosa were studied with specific regards to new beta-lactamases, including extended spectrum beta-lactamase [ESBL] and metallo-beta-lactamase [MBL]. Seventy six samples were collected from chronic discharging ear, 61 P. aeruginosa isolates were recovered [80.26%] on all media used. Gram positive bacteria were 100% inhibited on PASA, Kings A and Kings B, while Gram negative isolates were 100% inhibited on PASA only and not on other used media. The demarcation of P. aeruginosa colonies was detected in 100% on PASA, 19.67% on Kings A, 36.07% on Kings B, while nutrient and blood agar media could not demarcate colonies at all. ESBL was positive in 54.1%, negative in 24.59%, and indeterminate in 21.31% of pseudomonas isolates. The results of MBL test were 9.84% positive, 65.57% negative, 24.59% indeterminate. This reflects the serious problem of impending resistance of P. aeruginosa to all known sensitive drugs which increases the risk of chronicity of infections caused by these aggressive strains. Careful and experienced interpretation of the routinely done susceptibility testing of P. aeruginosa should be performed so as to predict the production of the new beta lactamases and to correctly formulate the susceptibility results in order not to mislead the clinicians. Special tests for confirmation of such resistance mechanisms are sometimes needed

Susceptibility testing of candida for fluconazole by Etest, fungitest and Broth Micro-dilution method

Three methods for fluconazole susceptibility testing of 120 isolates of Candida [54 C. albicans, 36 C. tropicalis, 12 C. krusei, 12 C. glabrata and 6 C. parapsilosis] were compared; namely the Broth Micro-dilution adaptation of the NCCLS method, the Pluconazole Etest, and the Fungitest system. The results of both Etest [read at 24 hours of incubation] and Fungitest were not statistically different and were found to be comparable to the standardized Broth-Micro dilution method. The agreement between the 24-hour Etest reading and the standard broth Micro-dilution method used for fluconazole susceptibility testing of Candida spp. as a whole was excellent [81%] and it ranged between fair to good [66%] for C. krusie and excellent 83%, 86%, and 100% for Candida albicans, C. tropicalis and C. glabrata respectively. The 48-hour Etest reading agreement with the reference Micro-dilution method was fair to good [55%] for all Candida spp. collectively as well as for C. albicans, but poor for C. tropicalis [30%] and C. glabrata [38%]. Major discrepancy was found only in one case [0.83%] and minor discrepancies were found in 9 cases [7.5%] by 24-hour Etest, while by 48-hour Etest, major discrepancies were found in 9 [7.5%] cases and minor discrepancies in 15 [12.5%] cases. Fungitest agreement studies with the standard test showed excellent agreement for C spp. as a whole and for C. albicans [79% and 76%] and fair to good agreement for C. tropicalis [73%]. Regarding Fungitest, major discrepancies were found in 4 cases [3.33%] and minor discrepancies were found in 11 cases [9.16%]. Etest and Fungitest are promising alternatives to the NCCLS reference methods for fluconazole susceptibility testing of Candida yet, further development is necessary to standardize their media, incubation conditions, and test procedures before their introduction as routine methods in the clinical microbiology laboratory

C-reactive protein in the evaluation of febrile illness in children suffering from respiratory tract infection

Thirty two children [18 males and 14 females] of 2-6 years old were included in this study. They were choosen from inpatient pediatric department of El-Zaharaa University Hospital. They were complaining from upper respiratory tract [URTI] or lower respiratory tract infection [LRTI] or both associated with fever since 2-4 days before admission. Full histories together with through clinical examination were carried out. No therapeutic treatment was given until blood sample was taken for routine laboratory tests which includes total white blood cell count [WBC] differential and erythrocyte sedimentation rate [ESR]. C-reactive protein was done to determine the diagnostic value of its serum estimation before and after effective therapeutic treatment for 7 days. We found that WBC, differential counts and ESR were of limited help and not conclusive for the diagnosis of RTI. Serum CRP was positive in all cases [p<0.001]. One week after treatment ten cases [31.25%] became CRP nrgative [p>0.05]. Two patients died, one from group E. and other from F. The rest of patients [20 i.e. 66.67%] CRP decreases [p<0.01]. The sensitivity, specificity and predictive accuracy of this test were 93.75%, 100%, 100% respectively

Systematic tolerance to the conventional and high copper dental amalgam implants

Freshly mixed, unset amalgam of four different types have been implanted in rats tibias for the purpose of evaluation of the effect of their corrosive products on some vital organs; the liver the kidney and blood. The animals were sacrificed after taking the blood samples at 1, 2, 4 and 6 week intervals. Liver and kidney function tests were done. The amount of copper and Zinc in the serum were measured using an Atomic Absorption spectrophotometer-. No significant differences were observed between the control group and the other different between the control group and the other different groups; the corrosive products of the different types of amalgam alloys did not affect the liver and kidney functions, the normal concentration of Cupper and Zinc in blood was not altered