Diffusion based methods versus automated mic in detecting drug resistance among nosocomial pathogens

The incidences ofnosocomial infections are varied in different studies, and the crude mortality is high, particularly for intensive-care unit [ICU] patients. The rates of antimicrobial resistance among pathogens causing health care-associated infections are increasing, and the main mechanisms that must be submitted to surveillance and accurate diagnosis are ESBL, AmpC and carbapenem resistance in gram negative bacilli, and MRSA and VRE in gram positive cocci. The aim of this study was to determine the incidence of the gram negative and gram positive resistance among nosocomial pathogens, to assess the abilities of diffusion based methods to detect different resistant patterns in relation to MIC profiles tested by the Sensititre automated system and to guide antimicrobial therapy policy in Benha locality. The study included total of 205 nosocomial specimens that were cultured and yielded 89 gram negative and 35 gram positive isolates. In our study we only included the nosocomial gram negative isolates resistant to 3rd generation cephalosporins [54] and the gram positive isolates resistant to vancomycin +/- methicillin [20] to be tested by Sensititre for identification and susceptibility testing. Diffusion based techniques used for confirmation of resistance of gram negative bacilli included ESBL screening by double disc diffusion test, imipenem [IMP]-EDTA combined disc test and ESBL and AmpC Detection Set [D68C system]

The incidence ofnosocomial MRSA among collected Staphylococcus aureus was 24.4%. According to diffusion based techniques, the rate of resistance to the 3rd generation cephalosporins among the 89 nosocomial gram negative isolates was as follows: for extended spectrum beta-lactamases 50 isolates [56.1%], for AmpC resistance 25 isolates [28.1%], and for carbapenem resistance 11 isolates [12.3%]

There was a suitable agreement between the results of Sensititre and diffusion based detection regarding ESBL and carbapenem resistance. However, results of Sensititre showed much higher number of AmpC in comparison with diffusion based detection

The reliance on only cefoxitin resistance by MIC testing is not a guarantee of establishing a diagnosis of AmpC. The highest resistance mechanisms were ESBL, followed by AmpC and carbapenem resistance, especially among Klebsiella pneumoniae isolates. Also, from our results, it was highly evident that there was a high endemicity of MRSA and VRE among our Gram positive cocci nosocomial isolates. It's recommended to confirm AmpC resistance by at least on phenotypic method, without complete reliance on the automated MIC results regarding this pattern of resistance

Serum non-protein bound Iron:a useful prognostic marker of neonatal asphyxia

Four million infants suffer from birth asphyxia allover the world each year; of them, one million dies and a similar number will develop serious sequelae; including hypoxic ischemia encephalopathy [HIE]. A better understanding of the pathogenesis of this event and its early identification is highly required. The role of non-protein bound iron [NPBI], lactate, and other laboratory and clinical criteria as diagnostic and prognostic markers were studied. This study included 25 asphyxiated neonates and 25 healthy matched neonates as a control group. Both groups were subjected to clinical assessment, routine laboratory tests, serum lactate and NPBI measurements. Clinical follow-up was done every three months till the age of 1 year. Developmental screening test was done every six months using Denver Developmental Screening Test [DDST]. Serum lactate levels were found to be significantly higher in the HIE group compared to the control group [t = 15.13, P < 0.001].HIE group [were divided into mild [10], moderate [7] and severe [8]] according to sarnat classification and there was a significant elevation in serum lactate levels in severe HIE in comparison to mild cases [P< 0.05]. Statistical analysis of serum NPBI levels in control group and HIE group revealed that there was a significant increase of NPBI in HIE group in comparison to control group [t= 7.02 P < 0.001, t= 9.89 P < 0.001, t= 13.3 P < 0.001 for mild, moderate, and severe subgroups respectively]. One way anova test revealed a significant elevation of the level of NPBI with the increase of severity in the studied subgroups [mild, moderate and severe] indicating that there is a correlation between the level of NPBI and the severity of the clinical presentation of HIE [F= 52.37, P < 0.001]. ROC curve was used to test the performance and clinical value of NPBI for predicting neurodevelopment outcome, and it indicated reliable performance for NPBI [ROC area under curve was 0.95]. We found a significant negative correlation coefficient between the level of NPBI and pH [r = -0.5794, P< 0.001], Na[+][r = -0.06084, P< 0.05], Ca[++[r = -0.7511, P < 0.001], Apgar score at 1 minute [r = -0.5766, P < 0.001], Apgar score at 5 minute,[r = -0.5248, P < 0.001] and pO-2[--] [r = -0.2668, P < 0.05]. A positive correlation coefficient was found between the level NPBI and HCO3 [r = 0.3568, P < 0.05], urea [r = 0.2681, P < 0.05], creatinine [r = 0.5552, P < 0.001], p[co][2] [r = 0.6053, P < 0.001], lactate [r = 0.5927, P < 0.001], and K[+] [r = 0.0855, P < 0.05]. All HIE cases devoid of neurological complications [manifested by seizures] had a normal development m contrast to HIE cases which complained from seizures [75%, 9 of 12 cases] after 6 months, and [81.8%, 9 of 11 cases] after 12 months had developmental delay tested by DDST. All of neurologically complicated cases [presented with seizures] had a significant elevation of the serum level of NPBI [P < 0.001. Serum NPBI assay may be a reliable early indicator of infra and extra-uterine oxidative stress and brain injury, with a prognostic value regarding HIE. use of free iron scavengers may be indicated of those cases with increased NPBI and eventual threat of HIE occurrence with its catastrophic complications

Serum soluble intracellular adhesion molecules-1 [sICAM-1] and AST/ALT ratio in chronic hepatitis C are significant predictors of the disease severity judged by liver biopsy

This study was conducted to investigate the serum levels of soluble Fas [sFas] antigen, soluble intracellular adhesion molecules-1 [sICAM-1] and interleukin-18 [IL-18] in patients with chronic hepatitis C and to correlate their levels with the severity of pathological findings judged by liver biopsy interpreted as Scheuer score. The study included 30 patients with chronic hepatitis C [Study group] infection persisting for longer than 6 months with HCV antibody positive and increased serum alanine aminotransferase [ALT] values and 10 volunteers to donate blood samples as control group. After complete history taking and full clinical examination, all patients and controls gave a fasting blood sample for colorimetric estimation of serum aspartate transaminase [AST], ALT and total [TB] and direct [DB] bilirubin and for ELISA assays of serum sICAM-1, sFas and IL- 18 levels. Blind liver biopsies were done and histopathological inflammatory activity [grading, 0-4 scale] and fibrosis stage [0-4 scale] were assessed according to Scheuer classification. Pathological examination of Liver biopsy detected 21 chronic hepatitis specimens and 9 cirrhosis specimens with a significant [p<0.05] increase of Scheuer scores in patients with cirrhosis compared to patients with chronic hepatitis. Serum levels of AST and ALT were significantly [p<0.05] elevated in study compared to control group, with a non-significant [p>0.05] increase of AST/ALT ratio; however, serum AST levels and AST/ALT ratio were significantly [p<0.05] higher and serum ALT levels were non-significantly [p>0.05] higher in cirrhotic patients compared to those with chronic hepatitis. Serum sFas, sICAM-1 and IL-18 levels in study group were significantly [p<0.05] higher compared to controls levels with a significant [p<0.05] increase of sICAM-1 levels and non-significant [p>0.05] increase of sFas and IL-18 levels in cirrhotic patients compared to patients with chronic hepatitis. There was a positive significant correlation between the mean Scheuer necroinflammatory score and serum levels of ALT, sICAM-1 and AST/ALT ratio and between the mean Scheuer fibrosis score and serum levels of ALT, sFas, sICAM-1 and IL-18 and AST/ALT ratio. Logistic regression analysis showed that AST/ALT ratio [beta=0.679, p<0.001] and serum levels of sICAM-1, [beta=0.327, p=0.005] are the most significant predictors of disease severity. It could be concluded that serum levels of sICAM-1, sFas and IL- 18 and AST/ ALT ratio are closely correlated with histopathological results of liver biopsy and thus their elevated levels could be considered pathognomonic markers suggesting the severity of chronic hepatitis C