Analysis of a new phage, KZag1, infecting biofilm of Klebsiella pneumoniae: genome sequence and characterization.

BACKGROUND: This study investigates the effectiveness of the bacteriophage KZag1 against drug-resistant Klebsiella pneumoniae, aiming to assess its potential as a therapeutic agent. The novelty lies in the characterization of KZag1, a Myovirus with specific efficacy against multidrug-resistant K. pneumoniae strains. This highlights the significance of exploring alternative strategies, particularly phage therapy, in addressing biofilm-associated infections. METHODS: KZag1, characterized by a typical Myovirus structure with a 75 ± 5 nm diameter icosahedral head and a 15 ± 5 nm short tail, was evaluated in experimental trials against 15 strains of K. pneumoniae. The infection cycle duration was determined to be 50 min, resulting in an estimated burst size of approximately 83 plaque-forming units per colony-forming unit (PFU/CFU). Stability assessments were conducted within a pH range of 4 to 12 and temperatures ranging from 45°C to 60°C. Biofilm biomass reduction was observed, particularly at a multiplicity of infection (MOI) of 10. RESULTS: KZag1 demonstrated infection efficacy against 12 out of 15 tested K. pneumoniae strains. The phage exhibited stability across a broad pH range and at elevated temperatures. Notably, treatment with KZag1 significantly reduced K. pneumoniae biofilm biomass, emphasizing its potential in combating biofilm formation. Genomic analysis revealed a complete genome of 157,089 base pairs with a GC content of 46.38%, encompassing 203 open reading frames (ORFs) and a cysteine-specific tRNA sequence. Comparison with phage GP4 highlighted similarities, with KZag1 having a longer genome by approximately 4829 base pairs and a higher GC content by approximately 0.93%. Phylogenetic analysis classified KZag1 within the Myoviridae family. CONCLUSION: The efficacy of KZag1 against K. pneumoniae biofilm suggests its potential as a therapeutic candidate, especially for drug-resistant infections. Further clinical research is warranted to explore its synergy with other treatments, elucidate genomic traits, compare with Myoviridae phages, and understand its host interactions. These findings underscore the promising role of KZag1 in addressing drug-resistant bacterial infections.

Alpha-sitosterol: a new antiviral agent produced by Streptomyces misakiensis and its potential activity against Newcastle disease virus.

BACKGROUND: Newcastle Disease Virus (NDV) causes severe economic losses in the poultry industry worldwide. Hence, this study aimed to discover a novel bioactive antiviral agent for controlling NDV. Streptomyces misakiensis was isolated from Egyptian soil and its secondary metabolites were identified using infrared spectroscopy (IR), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. The inhibitory activity of bioactive metabolite against NDV were examined. Three experimental groups of 10-day-old specific pathogen-free embryonated chicken eggs (SPF-ECEs), including the bioactive metabolite control group, NDV control positive group, and α-sitosterol and NDV mixture-treated group were inoculated. RESULTS: α-sitosterol (Ethyl-6-methylheptan-2-yl]-10,13-dimethyl-dodecahydro-1H-cyclopenta[a]phenanthren-3-ol), a secondary metabolite of S. misakiensis, completely inhibited hemagglutination (HA) activity of the NDV strain. The HA activity of the NDV strain was 8 log2 and 9 log2 for 0.5 and 0.75% RBCs, respectively. The NDV HA activity for the two concentrations of RBCs was significantly (P < 0.0001) inhibited after α-sitosterol treatment. There was a significant (P < 0.0001) decrease in the log 2 of HA activity, with values of - 0.500 (75%, chicken RBCs) before inoculation in SPF-ECEs and - 1.161 (50%, RBCs) and - 1.403 (75%, RBCs) following SPF-ECE inoculation. Compared to ECEs inoculated with NDV alone, the α-sitosterol-treated group showed improvement in histological lesion ratings for chorioallantoic membranes (CAM) and hepatic tissues. The CAM of the α-sitosterol- inoculated SPF-ECEs was preserved. The epithelial and stromal layers were noticeably thicker with extensive hemorrhages, clogged vasculatures, and certain inflammatory cells in the stroma layer in the NDV group. However, mild edema and inflammatory cell infiltration were observed in the CAM of the treated group. ECEs inoculated with α-sitosterol alone showed normal histology of the hepatic acini, central veins, and portal triads. Severe degenerative alterations, including steatosis, clogged sinusoids, and central veins, were observed in ECEs inoculated with NDV. Mild hepatic degenerative alterations, with perivascular round cell infiltration, were observed in the treated group. CONCLUSION: To the best of our knowledge, this is the first study to highlight that the potentially bioactive secondary metabolite, α-sitosterol, belonging to the terpene family, has the potential to be a biological weapon against virulent NDV. It could be used for the development of innovative antiviral drugs to control NDV after further clinical investigation.

Detection of multidrug-resistant Shiga toxin-producing Escherichia coli in some food products and cattle faeces in Al-Sharkia, Egypt: one health menace.

BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen, that is transmitted from a variety of animals, especially cattle to humans via contaminated food, water, feaces or contact with infected environment or animals. The ability of STEC strains to cause gastrointestinal complications in human is due to the production of Shiga toxins (sxt). However, the transmission of multidrug-resistance STEC strains are linked with a severity of disease outcomes and horizontal spread of resistance genes in other pathogens. The result of this has emerged as a significant threat to public health, animal health, food safety, and the environment. Therefore, the purpose of this study is to investigate the antibiogram profile of enteric E. coli O157 isolated from food products and cattle faeces samples in Zagazig City, Al-Sharkia, Egypt, and to reveal the presence of Shiga toxin genes stx1 and stx2 as virulence factors in multidrug-resistant isolates. In addition to this, the partial 16S rRNA sequencing was used for the identification and genetic recoding of the obtained STEC isolates. RESULTS: There was a total of sixty-five samples collected from different geographical regions at Zagazig City, Al-Sharkia-Egypt, which were divided into: 15 chicken meat (C), 10 luncheon (L), 10 hamburgers (H), and 30 cattle faeces (CF). From the sixty-five samples, only 10 samples (one from H, and 9 from CF) were identified as suspicious E. coli O157 with colourless colonies on sorbitol MacConkey agar media with Cefixime- Telurite supplement at the last step of most probable number (MPN) technique. Eight isolates (all from CF) were identified as multidrug-resistant (MDR) as they showed resistance to three antibiotics with multiple antibiotic resistance (MAR) index ≥ 0.23, which were assessed by standard Kirby-Bauer disc diffusion method. These eight isolates demonstrated complete resistance (100%) against amoxicillin/clavulanic acid, and high frequencies of resistance (90%, 70%, 60%,60%, and 40%) against cefoxitin, polymixin, erythromycin, ceftazidime, and piperacillin, respectively. Those eight MDR E. coli O157 underwent serological assay to confirm their serotype. Only two isolates (CF8, and CF13), both from CF, were showed strong agglutination with antisera O157 and H7, as well as resistance against 8 out of 13 of the used antibiotics with the highest MAR index (0.62). The presence of virulence genes Shiga toxins (stx1 and stx2) was assessed by PCR technique. CF8 was confirmed for carrying stx2, while CF13 was carrying both genes stx1, and stx2. Both isolates were identified by partial molecular 16S rRNA sequencing and have an accession number (Acc. No.) of LC666912, and LC666913 on gene bank. Phylogenetic analysis showed that CF8, and CF13 were highly homologous (98%) to E. coli H7 strain, and (100%) to E. coli DH7, respectively. CONCLUSION: The results of this study provides evidence for the occurrence of E. coli O157:H7 that carries Shiga toxins stx1 and/or stx2, with a high frequency of resistance to antibiotics commonly used in human and veterinary medicine, in Zagazig City, Al-Sharkia, Egypt. This has a high extent of public health risk posed by animal reservoirs and food products with respect to easy transmission causing outbreaks and transfer resistance genes to other pathogens in animal, human, and plants. Therefore, environmental, animal husbandry, and food product surveillance, as well as, clinical infection control, must be strengthened to avoid the extra spread of MDR pathogens, especially MDR STEC strains.

Streptomyces coeruleorubidus as a potential biocontrol agent for Newcastle disease virus.

BACKGROUND: Newcastle disease virus (NDV) is a severe disease that affects domestic and wild birds. Controlled antibiotics derived from probiotics have been examined as prospective solutions for preserving seroconversion in NDV-vaccinated fowl. In this study, the secondary metabolite "telomycin" was extracted from Streptomyces coeruleorubidus (S. coeruleorubidus) isolated from Egypt's cultivated soil. The structure of telomycin was determined by the elucidation of spectroscopic analysis, including nuclear magnetic resonance (NMR) and mass spectrometry (MS) spectra, and comparison with the literature. The antiviral activity of the secondary metabolite was tested by checking its effect on NDV hemagglutination activity (HA). Moreover, HA of NDV was tested after inoculation of NDV (control) and a combination of telomycin and NDV in 10- days- specific pathogen-free embryonated chicken eggs (SPF-ECE) daily candling. Histopathological examination was performed for chorioallantoic membranes and liver of SPF-ECE. RESULTS: S. coeruleorubidus secondary metabolite "telomycin" showed complete hemagglutination inhibition (HI) activity of NDV strain (MN635617) with log106 infectivity titers (EID50/mL). The HA of NDV strain was 8 log2 and 9 log2 with 0.5% and 0.75% of chicken RBCs, respectively. Preserved structures of chorioallantoic-membranes (CAM) with dilated capillary networks were observed in the treated group inoculated with telomycin and NDV. Histological changes in SPF-ECE liver were examined after inoculation in ova to further characterize the telomycin effect. Telomycin and NDV mixture inoculated group showed preserved cytoarchitecture of hepatocytes with the presence of perivascular foci of lymphocytes. The group that was inoculated with telomycin alone showed normal histology of hepatic acini, central veins, and portal triads. CONCLUSION: S. coeruleorubidus telomycin is a promising bioactive agent that might be a biological weapon against a deadly chicken NDV that costs farmers a lot of money.

The Healing Capability of Clove Flower Extract (CFE) in Streptozotocin-Induced (STZ-Induced) Diabetic Rat Wounds Infected with Multidrug Resistant Bacteria.

Treatment of diabetic foot ulcer (DFU) is of great challenge as it is shown to be infected by multidrug resistant bacteria (MDR bacteria). Sixty four bacterial isolates were isolated from DFU cases; antibiotic susceptibility tests were carried out for all of them. One bacterial isolate (number 11) was shown to resist the action of 8 out of 12 antibiotics used and was identified by both a Vitek-2 system and 16S rRNA fingerprints as belonging to Proteus mirabilis, and was designated Proteus mirabilis LC587231 (P. mirabilis). Clove flower extract (CFE) inhibited distinctively the P. mirabilis bacterium obtained. GC-MS spectroscopy showed that this CFE contained nine bioactive compounds. The effect of CFE on wound healing of Type 1 diabetic albino rats (Rattus norvegicus) was studied. The results indicated that topical application of CFE hydrogel improved wound size, wound index, mRNA expression of the wound healing markers (Coli1, MMP9, Fibronectin, PCNA, and TGFß), growth factor signaling pathways (PPAR-α, PGC1-α, GLP-1, GLPr-1, EGF-ß, EGF-ßr, VEGF-ß, and FGF-ß), inflammatory cytokine expression (IL8, TNFα, NFKß, IL1ß, and MCP1), as well as anti-inflammatory cytokines (IL4 & IL10), pro-apoptotic markers (FAS, FAS-L, BAX, BAX/BCL-2, Caspase-3, P53, P38), as well as an antiapoptotic one (BCL2). Furthermore, it improved the wound oxidative state and reduced the wound microbial load, as the cefepime therapy improved the wound healing parameters. Based on the previous notions, it could be concluded that CFE represents a valid antibiotics alternative for DFU therapy since it improves diabetic wound healing and exerts antibacterial activity either in vitro or in vivo.

Adjuvant effect of saponin in an oil-based monovalent (serotype O) foot-and-mouth disease virus vaccine on the antibody response in guinea pigs and cattle.

To enhance the potency of a foot-and-mouth disease (FMD) vaccine, saponin was included in the vaccine formula. In this study, the combined effect of Montanide ISA 50 and saponin was evaluated. Two experiments were performed in guinea pigs and one in cattle to determine the optimal antigen and saponin doses. Only serotype O of foot-and-mouth disease virus (O/PanAsia-2 of ME-SA topotype) was employed in preparation of the monovalent vaccine. All animals were immunized twice with a four-week interval, except for the negative controls. Blood was collected 10 days after the second booster, and the immune response was evaluated using a serum neutralization test. Oil-based FMD vaccines containing saponin induced higher neutralizing antibody levels than formulations lacking saponin. The addition of saponin to formulations with low antigen payload (2.5 µg of inactivated whole virus particles [146S particles] per dose) gave significantly higher neutralizing antibody levels (p < 0.005) than 5 µg of 146S without saponin, suggesting that it can be used to improve FMD vaccine potency in susceptible animals. No adverse effects were observed in vaccinated cattle or guinea pigs.

Occult hepatitis B infection in Egyptian health care workers.

We tested the frequency of occult hepatitis B infection (OBI) among Egyptian healthcare workers (HCWs). We tested 132 HCWs for hepatitis B virus (HBV) DNA by nested polymerase chain reaction (PCR), and hepatitis C virus antibody (anti-HCV) by ELISA. HCV RNA was measured by nested PCR in anti-HCV-positive HCWs. HBV-DNA-positive HCWs were subjected to HBV genotyping. We included 132 HCWs who were negative for hepatitis B surface antigen and positive for hepatitis B core antibody (anti-HBc). OBI was detected in 7 male HCWs, and HBV E genotype was detected in 3, HBV D in 2 and HBV D and E in 2. Two OBI-positive HCWs had a history of neonatal hepatitis B vaccination. Anti-HCV seropositivity was detected in 17 HCWs who were positive for anti-HBc; 15 of whom were positive for HCV RNA by nested PCR. HCV infection was confirmed by anti-HCV and HCV RNA in 1 of 7 HCWs with OBI. In conclusion, Egyptian HCWs have a significant rate of OBI and HBV E genotype is prevalent.

Isolation and characterization of T7-like lytic bacteriophages infecting multidrug resistant Pseudomonas aeruginosa isolated from Egypt.

In this study, two lytic phages designated as ϕPSZ1 and ϕPSZ2 infecting multidrug resistant Pseudomonas aeruginosa were isolated from sewage samples collected in Zagazig, Egypt. Morphological analysis by transmission electron microscopy revealed that both phages belong to the podoviridae family and resembles typical T7-like phages. ϕPSZ1 has a head of about 60 ± 5 nm in diameter with a short tail of 19 ± 2 nm in length, while ϕPSZ2 has a head of about 57 ± 5 nm in diameter with a short tail of 14 ± 2 nm in length. Both phages were shown to be able to infect 13 different P. aeruginosa strains and has no effect on other tested bacteria. In spite of morphological similarity, these phages showed diverged genomic sequences revealed by restriction enzyme digestion analysis. One-step growth curves of bacteriophages revealed eclipse and latent periods of 12 min for ϕPSZ1 and 15 min for ϕPSZ2, respectively, with burst sizes of about 100 per infected cell. Phage treatment prevented the growth of P. aeruginosa for up to 18 h with multiplicity of infection ratios of 1. These results suggest that both phages have a high potential for phage application to control P. aeruginosa.

Pseudomonas Phage ZCPS1 Endolysin as a Potential Therapeutic Agent.

The challenge of antibiotic resistance has gained much attention in recent years due to the rapid emergence of resistant bacteria infecting humans and risking industries. Thus, alternatives to antibiotics are being actively searched for. In this regard, bacteriophages and their enzymes, such as endolysins, are a very attractive alternative. Endolysins are the lytic enzymes, which are produced during the late phase of the lytic bacteriophage replication cycle to target the bacterial cell walls for progeny release. Here, we cloned, expressed, and purified LysZC1 endolysin from Pseudomonas phage ZCPS1. The structural alignment, molecular dynamic simulation, and CD studies suggested LysZC1 to be majorly helical, which is highly similar to various phage-encoded lysozymes with glycoside hydrolase activity. Our endpoint turbidity reduction assay displayed the lytic activity against various Gram-positive and Gram-negative pathogens. Although in synergism with EDTA, LysZC1 demonstrated significant activity against Gram-negative pathogens, it demonstrated the highest activity against Bacillus cereus. Moreover, LysZC1 was able to reduce the numbers of logarithmic-phase B. cereus by more than 2 log10 CFU/mL in 1 h and also acted on the stationary-phase culture. Remarkably, LysZC1 presented exceptional thermal stability, pH tolerance, and storage conditions, as it maintained the antibacterial activity against its host after nearly one year of storage at 4 °C and after being heated at temperatures as high as 100 °C for 10 min. Our data suggest that LysZC1 is a potential candidate as a therapeutic agent against bacterial infection and an antibacterial bio-control tool in food preservation technology.

Bioactive metabolites of Streptomyces misakiensis display broad-spectrum antimicrobial activity against multidrug-resistant bacteria and fungi.

Background: Antimicrobial resistance is a serious threat to public health globally. It is a slower-moving pandemic than COVID-19, so we are fast running out of treatment options. Purpose: Thus, this study was designed to search for an alternative biomaterial with broad-spectrum activity for the treatment of multidrug-resistant (MDR) bacterial and fungal pathogen-related infections. Methods: We isolated Streptomyces species from soil samples and identified the most active strains with antimicrobial activity. The culture filtrates of active species were purified, and the bioactive metabolite extracts were identified by thin-layer chromatography (TLC), preparative high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS). The minimum inhibitory concentrations (MICs) of the bioactive metabolites against MDR bacteria and fungi were determined using the broth microdilution method. Results: Preliminary screening revealed that Streptomyces misakiensis and S. coeruleorubidus exhibited antimicrobial potential. The MIC50 and MIC90 of S. misakiensis antibacterial bioactive metabolite (ursolic acid methyl ester) and antifungal metabolite (tetradecamethylcycloheptasiloxane) against all tested bacteria and fungi were 0.5 µg/ml and 1 µg/mL, respectively, versus S. coeruleorubidus metabolites: thiocarbamic acid, N,N-dimethyl, S-1,3-diphenyl-2-butenyl ester against bacteria (MIC50: 2 µg/ml and MIC90: 4 µg/mL) and fungi (MIC50: 4 µg/ml and MIC90: 8 µg/mL). Ursolic acid methyl ester was active against ciprofloxacin-resistant strains of Streptococcus pyogenes, S. agalactiae, Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica serovars, colistin-resistant Aeromonas hydrophila and K. pneumoniae, and vancomycin-resistant Staphylococcus aureus. Tetradecamethylcycloheptasiloxane was active against azole- and amphotericin B-resistant Candida albicans, Cryptococcus neoformans, C. gattii, Aspergillus flavus, A. niger, and A. fumigatus. Ursolic acid methyl ester was applied in vivo for treating S. aureus septicemia and K. pneumoniae pneumonia models in mice. In the septicemia model, the ursolic acid methyl ester-treated group had a significant 4.00 and 3.98 log CFU/g decrease (P < 0.05) in liver and spleen tissue compared to the infected, untreated control group. Lung tissue in the pneumonia model showed a 2.20 log CFU/g significant decrease in the ursolic acid methyl ester-treated group in comparison to the control group. The haematological and biochemical markers in the ursolic acid methyl ester-treated group did not change in a statistically significant way. Moreover, no abnormalities were found in the histopathology of the liver, kidneys, lungs, and spleen of ursolic acid methyl ester-treated mice in comparison with the control group. Conclusion: S. misakiensis metabolite extracts are broad-spectrum antimicrobial biomaterials that can be further investigated for the potential against MDR pathogen infections. Hence, it opens up new horizons for exploring alternative drugs for current and reemerging diseases.

Bacteriophages to Control Multi-Drug Resistant Enterococcus faecalis Infection of Dental Root Canals.

Phage therapy is an alternative treatment to antibiotics that can overcome multi-drug resistant bacteria. In this study, we aimed to isolate and characterize lytic bacteriophages targeted against Enterococcus faecalis isolated from root canal infections obtained from clinics at the Faculty of Dentistry, Ismalia, Egypt. Bacteriophage, vB_ZEFP, was isolated from concentrated wastewater collected from hospital sewage. Morphological and genomic analysis revealed that the phage belongs to the Podoviridae family with a linear double-stranded DNA genome, consisting of 18,454, with a G + C content of 32.8%. Host range analysis revealed the phage could infect 10 of 13 E. faecalis isolates exhibiting a range of antibiotic resistances recovered from infected root canals with efficiency of plating values above 0.5. One-step growth curves of this phage showed that it has a burst size of 110 PFU per infected cell, with a latent period of 10 min. The lytic activity of this phage against E. faecalis biofilms showed that the phage was able to control the growth of E. faecalis in vitro. Phage vB_ZEFP could also prevent ex-vivo E. faecalis root canal infection. These results suggest that phage vB_ZEFP has potential for application in phage therapy and specifically in the prevention of infection after root canal treatment.

Predictors of the Therapeutic Response to Intralesional Bivalent HPV Vaccine in Wart Immunotherapy.

Variable intralesional immunotherapies have recently been proposed as a means of achieving a successful eradication of recurrent and recalcitrant human papillomavirus (HPV)-induced cutaneous and anogenital warts. The bivalent HPV vaccine is one of the newly proposed immunotherapeutic agents. We investigated the role of interleukin-4 (IL-4) and interferon-gamma (IFN-γ) as ex vivo immunologic predictors to estimate the response to the bivalent HPV vaccine as a potential immunotherapy for cutaneous and anogenital warts. Heparinized blood samples were withdrawn from forty patients with multiple recurrent recalcitrant cutaneous and anogenital warts and forty matched healthy control subjects. Whole blood cultures were prepared with and without bivalent HPV vaccine stimulation. Culture supernatants were harvested and stored for IL-4 and IFN-γ measurements using an enzyme-linked immunosorbent assay. A comparative analysis of IL-4 and IFN-γ levels in culture supernatants revealed a non-significant change between the patient and control groups. The bivalent HPV vaccine stimulated cultures exhibited a non-significant reduction in IL-4 levels within both groups. IFN-γ was markedly induced in both groups in response to bivalent HPV vaccine stimulation. The bivalent HPV vaccine can give a sensitive IFN-γ immune response ex vivo, superior to IL-4 and sufficient to predict both the successful eradication of HPV infection and the ultimate clearance of cutaneous and anogenital warts when the bivalent HPV vaccine immunotherapy is applied.

Characterization of φEf-vB1 prophage infecting oral Enterococcus faecalis and enhancing bacterial biofilm formation.

Introduction. Enterococcus faecalis is a facultative, anaerobic, opportunistic pathogen associated with medical and dental diseases. Bacterial phenotypic traits and pathogenesis are often influenced by lysogeny.Aim. The aim of this study was to characterize both the morphology and complete genome sequences of induced prophages purified from E. faecalis clinical isolates.Methodology. E. faecalis isolates were recovered from the roots of teeth of patients attending an endodontic clinic. The morphological features of isolated phage were characterized using transmission electron microscopy (TEM). DNA sequencing was performed using the Illumina MiSeq platform.Results. TEM indicated that the isolated φEf-vB1 prophage belongs to the family Siphoviridae. The φEf-vB1 prophage was stable over a wide range of temperatures and pH. Sequencing of φEf-vB1 DNA revealed that the phage genome is 37 561 bp in length with a G+C content of 37.6mol% and contained 53 ORFs. Comparison with previously predicted prophage genomes using blast revealed that φEf-vB1 has a high sequence similarity to previously characterized phage genomes. The lysogenic E. faecalis strain exhibited a higher biofilm formation capacity relative to the non-lysogenic strain.Conclusion. The current findings highlight the role of lysogeny in modification of E. faecalis properties and reveal the potential importance of prophages in E. faecalis biology and pathogenesis.

Occurrence of Bacillus thuringiensis and their phages in Yemen soil.

Bacillus thuringiensis (Bt) isolates were found in all samples of soil in nine Governorates of Yemen. From 384 isolates of Bacillus recovered from these soil samples after acetate selection, 104 isolates (27.1 %) were Bt. Five isolates of Bt were selected and insecticidal activity was tested against Culex pipiens, Callosobruchus maculatus and Spodoptera littoralis. The Bt isolate YH18 gave toxicity to all tested insects larvae. This study extended to isolate phages active against the selected Bt isolates. Five phages were isolated and classified into two groups of tailed phages. Four phages with long non-contractile tails and hexagonal heads (Siphoviridae) and one phage with very short tail and isometric head (Podoviridae). Susceptibility of selected Bt to infect by these phages was studied by spot-test technique. Also the Bt isolate no YH18 was resistant to all tested phages. This is the first report illustrates the diversity and the abundance of Bt and Bt phage in Yemen soil.

Absence of occult hepatitis B virus infection in sera of diabetic children and adolescents following hepatitis B vaccination.

BACKGROUND: The prevalence of occult hepatitis B (HB) infection (OBI) in HB-vaccinated diabetic children has not yet been tested. Here, we aimed to determine the prevalence of OBI among HB-vaccinated children and adolescents with insulin-dependent diabetes mellitus (IDDM). RESULTS: Eighty-seven (51.2%) children had a titer for antibodies to HB surface antigen (anti-HBs) of <10 IU/L. These included 44 (70%) IDDM children and 43 (40.2%) healthy children. Eighty-three (48.8%) children had an anti-HBs titer of ≥10 IU/L; they included 19 (30%) with IDDM and 64 (59.8%) healthy children. None of the enrolled children (n = 170) were reactive for total antibody to HB core antigen (anti-HBc) as determined by enzyme-linked immunosorbent assay. HB virus DNA was not detected in HB-vaccinated IDDM or healthy children and adolescents. METHOD: An amount of 170 HBsAg-negative sera samples from HB-vaccinated children and adolescents was included. They were classified into the IDDM group (n = 63) and the healthy control group (n = 107). HBsAg, anti-HBc, and anti-HBs were tested by enzyme-linked immunosorbent assay, and HB virus DNA was tested by nested polymerase chain reaction using 3 pairs of surface, core, and X genes. IN CONCLUSION: Primary HB vaccination confers long-term protection against OBI in Egyptian diabetic children and adolescents. However, the number of cases tested in this study was relatively low, and further studies and long-term follow-up of large populations are needed to draw solid and convincing conclusions.

Antibody levels against hepatitis B virus after hepatitis B vaccination in Egyptian diabetic children and adolescents.

BACKGROUND: The remarkable effectiveness of universal infantile hepatitis B (HB) vaccination is well documented in many countries. Nevertheless, the influence of insulin-dependent diabetes mellitus (IDDM) on the sero-protective level of antibody to hepatitis B surface antigen (anti-HBs) after HB vaccination has not been investigated in Egyptian children. The aim of this study was to investigate long-term anti-HBs sero-protective levels after infantile HB vaccination in Egyptian IDDM children. RESULTS: The mean age of the healthy children was 10.86 ± 1.21 y (range, 5.5-15 y); 49 (45.8%) were boys and 58 (54.2%) were girls. The mean age of the IDDM children was 10.29 ± 3.04 y (range, 4-17 y); 32 (50.8%) were boys and 31 (49.2%) were girls. There were no significant differences between the healthy and IDDM children with respect to age and sex (p>0.05). Among the 107 healthy children, 43 (40%) did not have a protective anti-HBs level (anti-HBs<10 IU/L) and 64 (60%) had a protective level (anti-HBs ≥ 10 IU/L). In contrast, among the IDDM children, 44 (69.8%) and 19 (30.2%) did not and did have protective anti-HBs levels, respectively. This difference in anti-HBs concentration between healthy and diabetic children was highly significant (p<0.001). None of the vaccinated healthy or IDDM children was reactive to HBsAg or total anti-HBc. PATIENTS AND METHODS: A total of 170 children (81 boys, 89 girls) who had been routinely vaccinated against HB were included. Their mean age was 10 ± 2.1 y. The enrolled children were divided into healthy (n = 107) and IDDM (n = 63) cohorts. Body Mass Index and levels of hepatitis B surface antigen (HBsAg), total antibody to hepatitis B core antigen (anti-HBc), and anti-HBs were evaluated in all children. In addition, the duration of diabetes mellitus (DM) and levels of glycated hemoglobin (HbA1c) were measured in IDDM children. CONCLUSION: Our results are alarming. It appears that the majority of Egyptian diabetic children vaccinated against HB may not have sufficient anti-HBs levels to protect them from HB. Moreover, this study emphasizes the need for a population-based strategy for the management of patients without an anti-HBs protective level after HB vaccination and justifies the need to elucidate the heritability of those children.

Occult hepatitis B infection in Egyptian health care workers

We tested the frequency of occult hepatitis B infection [OBI] among Egyptian healthcare workers [HCWs]. We tested 132 HCWs for hepatitis B virus [HBV] DNA by nested polymerase chain reaction [PCR], and hepatitis C virus antibody [anti-HCV] by ELISA. HCV RNA was measured by nested PCR in anti-HCV-positive HCWs. HBV-DNA-positive HCWs were subjected to HBV genotyping. We included 132 HCWs who were negative for hepatitis B surface antigen and positive for hepatitis B core antibody [anti-HBc]. OBI was detected in 7 male HCWs, and HBV E genotype was detected in 3, HBV D in 2 and HBV D and E in 2. Two OBI-positive HCWs had a history of neonatal hepatitis B vaccination. Anti-HCV seropositivity was detected in 17 HCWs who were positive for anti-HBc; 15 of whom were positive for HCV RNA by nested PCR. HCV infection was confirmed by anti-HCV and HCV RNA in 1 of 7 HCWs with OBI. In conclusion, Egyptian HCWs have a significant rate of OBI and HBV E genotype is prevalent

Nous avons étudié la fréquence de l'hépatite B occulte chez des agents de soins de santé égyptiens. Nous avons examiné 132 agents de santé à la recherche d'ADN du virus de l'hépatite B [VHB] au moyen de l'amplification en chaîne par polymérase [PCR] nichée et de l'anticorps du virus de l'hépatite C [anti-VHC] par la méthode ELISA. L'ARN du VHC a été mesurée par PCR nichée chez des agents de santé positifs pour l'anticorps anti-VHC. Les agents de santé positifs pour l'ADN du VHB ont été soumis au génotypage du VHB. Nous avons inclus 132 agents de soins qui étaient négatifs pour l'antigène de surface de l'hépatite B et positifs pour l'anticorps antinucléaire de l'hépatite B [Anti-HBc]. Une hépatite B occulte a été détectée chez 7 agents de santé de sexe masculin, et le VHB de génotype E a été détecté chez trois agents, le VHB de génotype D chez 2 agents, et le VHB de génotype D et E chez 2 agents. Deux des agents positifs pour l'hépatite B occulte avaient été vaccinés durant la période néonatale. Une séropositivité anti-VHC a été détectée chez 17 agents de santé qui étaient positifs pour l'anticorps anti-HBc, dont 15 étaient positifs pour l'ARN du VHC par PCR nichée. L'infection à VHC a été confirmée par l'anti-VHC et par l'ARN du VHC chez 1 agent sur 7 atteints d'hépatite B occulte. En conclusion, les agents de santé égyptiens ont un taux d'hépatite B occulte significatif et le génotype E du VHB est prevalent