Occult hepatitis C virus infection in Iranian hemodialysis patients.

BACKGROUND: Occult hepatitis C virus (HCV) infection is defined as the presence of HCV-RNA in liver or peripheral blood mononuclear cells (PBMCs) in the absence of detectable hepatitis C antibody (anti-HCV) or HCV-RNA in the serum. Low concentrations of HCV-RNA may be detected in PBMCs of hemodialysis (HD) patients and this could have a great impact on the management of HD patients. OBJECTIVES: The aim of this study was to detect the occult HCV infection in Iranian HD patients. PATIENTS AND METHODS: A total of 70 anti-HCV negative HD patients from three dialysis units in Tehran, Iran were included in this study. In these cases, presence of HCV-RNA in plasma samples was tested by reverse transcriptase-nested polymerase chain reaction (RT-nested PCR). In cases with negative anti-HCV and plasma HCV-RNA, genomic HCV-RNA was checked in PBMC specimens by RT-nested PCR. RESULTS: Seventy anti-HCV negative HD patients were enrolled in the study. 32.85% and 1.43% of cases had elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) respectively. 7.14% of patients had elevated levels of both ALT and AST. HCV-RNA was negative in plasma samples of all anti-HCV negative HD subjects. The genomic HCV-RNA was not detected in any PBMC samples of HD cases with negative anti-HCV and plasma HCV-RNA. CONCLUSIONS: Occult HCV infection was not detected in our HD patients despite of elevated levels of liver enzymes in some participants. Further studies involving larger number of HD patients are required to elucidate the rate of occult HCV infection in HD cases.

Seroepidemiology of hepatitis A virus in children of different age groups in Tehran, Iran: implications for health policy.

BACKGROUND: Hepatitis A is one of the most frequently reported vaccine-preventable diseases throughout the world and remains endemic in many areas. Studies in various communities have shown that Hepatitis A virus (HAV) prevalence rises with age. The current data regarding hepatitis A epidemiology in Iran is limited. The aim of this study was to determine the seroepidemiology of hepatitis A in children of different age groups in Tehran, Iran. METHODS: Plasma samples of 1065 children between ages of 6 months and 20 years were tested for the presence of total anti-HAV. The study population was stratified according to age. RESULTS: The prevalence of total anti-HAV was 61.6%. HAV prevalence rates according to age groups were as follows: 61.5% between 6 months and 1.9 years, 51.7% between 2 and 5.9 years, 52.9% between 6 and 10.9 years, 65.2% between 11 and 15.9 years, 85% between 16 and 20 years. Total anti-HAV seroprevalence was significantly different between age groups. CONCLUSION: The study findings indicate that hepatitis A is prevalent in children in Tehran, Iran and HAV infection is an important public health problem in this region.

Antibiotic-resistance patterns and frequency of extended-spectrum beta-lactamase-producing isolates of Klebsiella pneumoniae in Tehran.

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing strains of Klebsiella pneumoniae have caused major therapeutic problems worldwide since the majority are resistant to various antibiotics. In this study, an investigation was conducted regarding antibiotic-resistant patterns of 128 isolates of K pneumonile cultured from Iranian patients at two teaching hospitals during 2004-2005. MATERIAL/METHODS: The susceptibility of isolates to 21 antimicrobial agents was determined using the disk diffusion method. Disks containing ceftazidime, cefotaxime, ceftazidime/clavulanic acid, and cefotaxime/clavulanic acid were used in the phenotypic confirmatory (PCT) method to detect ESBL isolates. A comparison between the confirmatory method and double-disk synergy test (aztreonam, ceftazidime, ceftriaxone, cefotaxime, and amoxicillin/clavulanic acid) was also made to assign the appropriate method of detection for ESBLs. The E-test was used to determine the susceptibility of isolates to cefepime. RESULTS: All strains were susceptible to imipenem and meropenem. Resistance to ciprofloxacin and gentamicin were found in 37% (n=47) and 33% (n=42) of isolates, respectively. Production of ESBL was detected in 44.5% of isolates. Resistance to cefepime was found in 40% of isolates. CONCLUSIONS: The prevalence of ESBL strains in the study hospitals is high. The double-disk synergy method is not preferable in successfully detecting ESBL strains. More importantly, 33% of ESBL strains were also resistant to ciprofloxacin and aminoglycosides. Based on the laboratory results, it is recommended that prescription of cephalosporins be restricted to susceptible isolates and that the usage of other effective antibiotics be considered.

Genetic characterization of high-level gentamicin-resistant strains of Enterococcus faecalis in Iran.

The prevalence of resistance to high levels of gentamicin among 182 isolates of Enterococcus faecalis from 2 Iranian hospitals was 42%. Gentamicin resistance was associated with conjugative plasmids (>70 kb) in most strains. Fingerprinting using EcoRI and HindIII showed genetic variation among these plasmids and gave evidence of nosocomial outbreaks and persistence of infection in different wards of the study hospitals, as well as transfer of plasmids between genetically diverse isolates. Using EcoRI, hospital-based specific plasmid fingerprints were detected for the isolates that had previously proved to be unrelated by multilocus enzyme electrophoresis, suggesting the persistence of related plasmids at each hospital, though minor changes in these related plasmids could be detected with HindIII.

Phenotypic characteristics and population genetics of Enterococcus faecalis cultured from patients in Tehran during 2000-2001.

Conventional bacteriology techniques were used to identify enterococci isolates cultured from patients at different hospitals in Tehran during 2000-2001. The identification was confirmed using species-specific PCR targeting the D-alanyl-D-alanine ligase gene. A total of 59 isolates of Enterococcus faecalis were identified. The rates of resistance to different antibiotics were in the following order: penicillin 84%, ciprofloxacin 42%, high-level gentamicin 30%, nitrofurantoin 14%, imipenem 4%, and chloramphenicol 2%. Resistance to ampicillin was found to be rare among the Iranian isolates of E. faecalis. Multi-locus enzyme electrophoresis was then used to analyze the strains. Forty-five electrophoretic types were obtained when 10 enzyme loci were screened. Although the collection of bacterial isolates was limited in time and location, considerable heterogeneity was found. Analysis of strains for linkage disequilibrium demonstrated that the studied population is not clonal, since the index of association was not significantly different from zero (Ia = 0.0296). Enterococcus faecalis isolates recovered from patients in Tehran were genetically diverse and seemed to possess a high potential for genetic recombinations, though none were resistant to vancomycin.