Human immunodeficiency virus type 1 (HIV-1) is a causative agent of acquired immunodeficiency syndrome (AIDS) in humans. In the last decade, the functions of HIV-1-encoded genes have been intensively studied. These studies have contributed to the development of the effective anti-AIDS drugs directing against the HIV-1-encoded enzymes, namely reverse transcriptase and protease. However, even the combination of these drugs is not sufficient enough to stop the progression of AIDS partly due to the emergence of drug-resistant HIV-1 mutants as well as the severe side effects. Understanding the molecular mechanisms by which cellular factors support the efficient replication of HIV-1 should contribute to develop means to control the progression of AIDS. This field is now expanding rapidly. Here we review the host factors involved in the replication of HIV-1 and highlight some findings that have a substantial impact on the retroviral research.

Sphingolipids are ubiquitous constituents of membrane lipids in eukaryotes. Sphingolipid metabolites modulate various cellular events including proliferation, differentiation, and apoptosis. In addition, sphingolipids, along with cholesterol, form detergent-resistant membrane microdomains, so called ‘lipid-rafts’, which are implicated in signal transduction and membrane trafficking. Sphingolipids are also relevant to infectious diseases. Various types of pathogens exploit the sphingolipids of host cells as membrane receptors. Sphingolipid metabolites regulate pathogen infection and host defense: for instance, a specific glycosphingolipid acts as an endogenous ligand for activation of natural killer T cells. Lipid-rafts of host cells serve as platforms also for infection signaling and entry of intracellular parasites. Moreover, some post-infectious autoimmune diseases result from production of antibodies cross-reacting with mammalian sphingolipids. Differences in the pathways of sphingolipid metabolism between mammals and non-mammals are good clues for rational development of new anti-infectious disease drugs. This review summarizes recent advances in sphingolipid biology related to infectious diseases.

A 10-year-old male with a brain abscess developed pancytopenia, liver dysfunction, disseminated intravascular coagulation (DIC) and decrease of immunoglobulin A (IgA) level during postoperative antibiotic and anticonvulsant therapy. A bone marrow examination revealed hemophagocytosis. Real-time PCR revealed parvovirus B19 infection. The hemophagocytic syndrome resolved without specific treatment. To our knowledge, this is the first report of a spontaneous resolution of parvovirus B19-associated hemophagocytic syndrome and DIC.

The purpose of this study was to investigate various factors, including demographical, socio-economical, clinical and radiological features, of adherent and nonadherent patients with tuberculosis (TB) who were admitted to a university hospital between 1998 and 2003. One hundred and one patients (65.5%) and 53 patients (34.5%) met the criteria of adherence and nonadherence, respectively. A higher rate of adherence was observed among females than males (79.2 versus 58.4%, respectively, P = 0.012). Older patients were more nonadherent (P = 0.008). The adherence rate in non-smokers was significantly higher than that of smokers (81.4 and 52.4%, respectively, P = 0.000). Patients who underwent “family screening” were more adherent (75.7%) than those (39.5%) who did not (P = 0.000). Patients with pleurisy had higher adherence rates (81.3%), followed by patients with pulmonary TB (65.0%), while patients with extrarespiratory TB had the lowest adherence rates (45.5%) (P = 0.024). The presence of cough was significantly associated with adherence (P = 0.049). A significantly higher adherence rate was observed in patients without hemoptysis (P = 0.001). A univariate logistic regression confirmed that age, smoking, family screening, type of TB, cough and hemoptysis had significant independent effects on the adherence to treatment of TB. High-risk patients may be identified and interventions tailored to promote adherence before concluding that the patient is willfully refusing treatment.

Urinary tract infections are among the most common infections with an increasing resistance to antimicrobials. The aim of this study was to determine the change in antimicrobial susceptibility of Escherichia coli isolates from patients with community-acquired urinary tract infection (UTI) for the years 1998 through 2003 and to suggest that the current empirical antibiotic therapy used for these patients is inappropriate. During the study period, 7,335 community urine samples of which 1,203 (16.4%) grew bacterial isolates were analyzed. Among the total of 1,203 isolates, 880 (73.2%) were E. coli. The range of resistance of E. coli to ampicillin was 47.8 to 64.6% and that to trimethoprim-sulfamethoxazole was 37.1 to 44.6% during the study period. The susceptibility pattern of E. coli to nitrofurantoin and cefuroxime did not vary significantly over the 6-year period. There was a significant increase in the susceptibility of E. coli to ciprofloxacin (11.3 - 26.7%), amoxicillin-clavulanate (18.4 - 29.2%) and gentamicin (7.0 - 25.6%) (P < 0.05). Empirical initial treatment with ampicillin and trimethoprim-sulfamethoxazole was thus inadequate in approximately half of UTI cases in our region.

TEM- and SHV-derived extended-spectrum β-lactamases (ESBLs) producing Enterobacteriaceae have been reported from throughout the world, but there has been limited data for the molecular characterization of these enzymes in Turkey. The aim of this study was to investigate and to type the TEM- and SHV-derived ESBLs in 63 ESBL-producing clinical isolates of Enterobacteriaceae, and it included further analysis; transfer experiments, isoelectric focusing, PCR, PCR-restriction fragment length polymorphism, and DNA sequencing. According to PCR results the transconjugant strains included 52.7% TEM, 74.3% SHV, and 32.4% of both the TEM and SHV genes. Using PCR/NheI restriction analysis, 45 of the 46 ESBL detected in transconjugants were determined to be SHV-derived. DNA sequencing was performed for the identification of TEM- and SHV-derived ESBLs for 18 selected transconjugants. SHV-2, SHV-5, and SHV-12 were detected in five, seven, and five samples, respectively. This is the first description of SHV-12 in Turkey.

The clinical characteristics and therapeutic outcomes of adult meningitis due to Escherichia coli alone have not been examined adequately. In this study, we analyzed the clinical and laboratory data of 15 adult patients with monomicrobial E. coli meningitis. The 15 patients, collected over a period of 18 years (January 1986 - December 2003), included 7 men and 8 women, aged 45 - 77 years. They accounted for 5% (15/306) of our cases of adult bacterial meningitis with single pathogen infection. This study also revealed that a post-neurosurgical state is the most important factor predisposing adult patients to develop E. coli meningitis. In this study, all of the tested E. coli strains showed susceptibility to imipenem and/or meropenem, however, E. coli strains that are not susceptible to third-generation cephalosporin have emerged since 2001. As to the therapeutic results of these 15 cases, all 4 patients without appropriate antibiotic treatment died and the other 11 patients with appropriate antibiotic treatment showed a mortality rate of 27%. The emergence of third-generation cephalosporin non-susceptible E. coli strains in adult bacterial meningitis, as shown in this study, has created a therapeutic challenge in choosing initial empirical antibiotics for treating adult patients with post-neurosurgical meningitis. Our results emphasize that the timely use of appropriate antibiotics is essential for the management of this potentially fatal central nervous system infection. However, it should be noted that the number of cases examined in this study is too small to reach a therapeutic conclusion regarding adult E. coli meningitis, and further large-scale studies will be needed for this purpose.

In this prospective pilot study we evaluated the efficacy of blood cultures (BC) in detecting bacteremia and fungemia prior to the occurrence of infectious signs. Between February 2003 and July 2003, BC were performed twice weekly in neutropenic hematological patients using blood drawn from central venous catheters. Microbial growth prior to the onset of infectious symptoms was detected in 3 of 45 neutropenic episodes in 39 patients and led to modifications in patient management. These results suggest that further prospective studies are warranted to determine the clinical usefulness of surveillance with BC in neutropenic patients.

Bloodstream infections are associated with significant patient morbidity and mortality worldwide. In this study, we examined antimicrobial susceptibility patterns by reviewing the data on 5,704 blood samples that were collected from patients with fever/sepsis admitted to Government Medical College and Hospital, Chandigarh, India, over a period of 1 year from August 2003 to July 2004. Among the 567 qualifying samples, Pseudomonas aeruginosa (19.75%), Escherichia coli (15.17%), Klebsiella pneumoniae (14.99%), and Salmonella enterica serovar Typhi (12.87%) were the most frequently isolated Gram-negative bacteria other than Citrobacter, Acinetobacter, Proteus, and Enterobacter spp. collectively accounting for 80.96% of the isolates. Staphylococus aureus (13.86%) and Enterococcus feacalis (2.35%) were most frequently isolated Gram-positive bacteria other than other Streptococcus and Staphylococcus spp. collectively accounting for 18% of the isolates. Among the antibiotics used for susceptibility testing of Gram-negative isolates, amikacin showed higher activity (76.61%) against Enterobacteriaceae and ciprofloxacin (65.17%) against non-fermenters. However, cefoperazone + sulbactum showed the highest activity (82.66%) among all Gram-negative isolates. For Gram-positive isolates, vancomycin (100%), ciprofloxacin (89.74%) showed the highest activity against Staphylococcus spp. Combinations of antibiotics are often prescribed as emperic therapy for bacteremia, especially for Gram-negative pathogens. Hence the antibiotic susceptibility patterns of blood isolates reported here may be a useful guide for physicians initiating emperic therapy with antibiotics.

Because spinal epidural abscess is usually ignored in the preliminary differential diagnosis of low back pain, appropriate treatment may be delayed. Adult spinal epidural abscess is sparsely caused by the pathogen known as group B Streptococcus. In this paper, we report the case of a diabetic woman with lumbar epidural abscess and vertebral osteomyelitis caused by group B Streptococcus. Owing to the main manifestations of fever, pyuria and low back pain, which originally led us to suspect acute pyelonephritis, empirical antibiotics were applied. When the symptoms and signs persisted, other focal infections were considered. Magnetic resonance imaging led to the correct diagnosis. Group B Streptococcus was isolated from the blood but not from the abscess itself, probably due to the prior antibiotic treatment. The patient recovered well after surgical debridement followed by prolonged intravenous penicillin therapy. Therefore, despite the potential for fatality, our results suggest that epidural abscess can be successfully treated with surgery and antibiotic therapy provided that it is detected early enough.

In order to evaluate the reliability of pulsed-field gel electrophoresis (PFGE) analysis performed at different prefectural public health institutes (PHIs) for use in the PulseNet Japan surveillance system to detect enterohemorrhagic Escherichia coli O157, we compared the results of PFGE-typing of 14 selected strains of O157 performed at 8 selected PHIs to evaluate the reliability of different experimental protocols used in these PHIs. PFGE was performed for 14 strains for which there were 14 PFGE types in 3 PHIs, and 13 PFGE types in 5 PHIs by using their own protocols and/or those of the National Institute of Infectious Diseases (NIID). PFGE fingerprints from 5 out of the 8 PHIs were successfully genotyped for all of the 14 strains. A PFGE fingerprint from one PHI was successfully genotyped when the NIID pulsing protocol was used, but was not genotyped when the PHI’s own protocols were used. PFGE fingerprints from 2 PHIs failed to be genotyped for one each of the strains. The cause of this genotyping failure was considered to be inappropriate PFGE pulsing protocols or inadequate digestion of chromosomal DNA. These results suggest that PFGE protocols should be standardized for the establishment of PulseNet Japan.

Based on specific sequencing, we found that a Borrelia garinii strain from a rodent in Fukui Prefecture, Japan was highly similar to the unique Borrelia strains (pattern R´/R) isolated in northeastern China and Korea, and to strains from ticks feeding on migratory birds in Fukui Prefecture. These findings indicate that the Borrelia with this unique pattern may be locally naturalized to the epizootic transmission cycle in Japan, and that Borrelia is dispersed from the Asian Continent to Japan via migratory birds.