Major hydrophilic region in genomic HBV extending from aa99 to aa169, clustered with a highly conformational epitope, is critical to the antigenicity of hepatitis B surface antigen (HBsAg) and may affect the diagnosis of HBV in HBV screening test. So, this study aimed to characterize variants of S gene product of hepatitis B virus (HBV) isolated from patients with overt or occult HBV infection in north-eastern Egypt. The study included sera of two different groups of volunteer blood donors (VBDs), 82 with overt HBV that were positive for HBsAg and anti-HBc and 343 donors negative for HBsAg eligible for donation. Of the latter group, only 44 were positive for anti-HBc. All anti-HBc positive sera were subjected to HBV DNA detection and partial sequence analysis targeting the HBV S gene. HBV DNA was detected in 22.7 % of HBsAg-/anti-HBc + (10/44 patients) and in 90 % of HBsAg + donors (74/82 patients) with significant statistical difference (P = 0.0001). Phylogenetic analysis showed that HBV strains retrieved from both groups were of genotype D. Amino acid escape mutation T125M was detected in only 2 samples of the occult infection group and in none of the overt group (P = 0.01). Different amino acid substitutions were identified in overt infection group: S143L/T (16.2 %, 12/74) and P120T/S (2.7 %, 2/74). Q129R was significantly more frequent in cases with occult HBV infection (40 %, 4/10) than overt group (6.8 %, 5/74) (P = 0.01). HBV genotype D predominated both in patients with overt and occult HBV infection. Different profiles of amino acid substitutions in the major hydrophilic region were seen in these two groups in Egypt.

One of the serious and growing challenges for infection control programs worldwide is hospital acquired infections. Klebsiella pneumoniae is considered the second most common cause of hospital-acquired Gram-negative blood stream infections. Chlorhexidine is a topical antiseptic agent, widely used in different applications in hospitals. Healthcare associated infection rates were lower after chlorhexidine-containing detergent hand washing when compared with using plain soap or an alcohol-based hand rinse. Intensive exposure of hospital pathogens to biocides may result in the emergence of resistance not just to the biocides but also to antibiotics. We aimed to investigate the susceptibility of multi-drug resistant K. pneumoniae isolates to chlorhexidine and to correlate chlorhexidine susceptibility and its association with both the efflux pump genes (cepA, qacDE, qacE), and resistance to later-generation anti-Gram negative antibiotics. Fifty-six strains of K. pneumoniae were isolated from blood specimens in intensive care units, Suez Canal University Hospital, Ismailia, Egypt. Antibiotic sensitivity profiles were determined by disc diffusion method. Minimal inhibitory concentration (MICs) of 1% chlorhexidine was assessed by the agar dilution method. The effect of efflux pumps was determined by repeating the susceptibility in the presence of the efflux pump inhibitor carbonyl cyanide m-chlorophenyl hydrazone (CCCP) (10 mg/L). Polymerase chain reaction (PCR) was used for identifying efflux pump genes. The MICs of chlorhexidine ranged from 4 - 256 mg/L. Most isolates carried the cepA gene. The MICs of chlorhexidine was significantly reduced on addition of CCCP. Carriage of efflux pump gene cepA affect chlorhexidine susceptibility in ICU related K. pneumoniae infections. Key words: Klebsiella pneumoniae, chlorhexidine, efflux pump, ICU.