Mice recovered from influenza A virus infection have been shown to be cross-protected against challenge infection with either drift viruses within a subtype (subtype-specific immunity) or different subtype viruses (heterosubtypic immunity). The mechanisms of broad-spectrum cross-protection could be explained as follows. (i) Pre-existing S-IgA and IgG antibodies (Abs) induced by infection are involved in the elimination of challenge viruses by forming virus–Ig complexes shortly after re-infection. Due to their polymeric nature, the S-IgA Abs, existing more abundant on the mucosa than are IgG Abs, are strongly cross-reactive with challenge viruses, whereas the IgG Abs are weakly cross-reactive with challenge viruses, due to their monomeric nature. The specificity of Abs is directed mainly at hemagglutinin and neuraminidase. (ii) CD8⁺ memory T cells induced by infection are involved in the elimination of challenge viruses by the accelerated killing of host cells infected with different subtype viruses from day 3 onwards after re-infection. The specificity of memory T cells is directed against viral internal proteins. (iii) The accelerated IgA and IgG Ab responses, produced by B memory cells after a challenge, are also involved in cross-protection from day 4 onwards after re-infection. (iv) In the epithelial cells of infected mice, dimeric IgA that is trafficked through the epithelial cells can contribute to the prevention of viral assembly by binding to newly synthesized viral proteins. Natural infection is well known to be superior to parenteral inactivated vaccines in inducing the broad-spectrum cross-protection. To improve the efficacy of current inactivated vaccines, many trials have been conducted to mimic natural infection, including intranasal or epidermal administration of inactivated vaccine with or without an adjuvant; such studies are still ongoing. In the near future, some of these trials may provide new, safer and more effective broad-spectrum vaccines than those currently available.

In Indira Gandhi Medical College, Himachal Pradesh, India, during autumn of 2003 (September-November), more than 100 cases of fever of unknown origin (FUO) were reported with 15 ensuing deaths. In addition to all routine investigations and cultures, the Weil-Felix test was incorporated for the investigation of these cases. Antigen was procured from the Central Research Institute, Kasauli. Forty-six percent (45/96) of the cases demonstrated a ≥1:80 titer of agglutinins against OXK antigen. A team from the National Institute of Communicable Diseases, New Delhi, confirmed the antibodies for scrub typhus in some of the serum samples tested for leptospirosis, dengue fever, and rickettsial infections. Twelve blood samples positive for OXK antigen were sent to the Defense Research Development Establishment, Gwalior, for polymerase chain reaction studies, but none of the samples were positive, as all of the patients were already on broad-spectrum antibiotics and had reported to our hospital after 7 - 10 days of fever. At our institute, the Weil-Felix test has now been rountinely introduced for the investigation of cases of FUO, and the results until April 2004 (150 cases) revealed the presence of other rickettsial infections prevalent in the region. To evaluate the epidemiology and magnitude of the problem, further prospective studies are required.

The distribution of Chlamydia trachomatis serovars in Thailand and Japan during the same period of the mid-90s was determined. Seventy-one C. trachomatis specimens isolated from female patients who visited the Venereal Diseases Center at Bangkok, Thailand in 1994 were used in this study. Of these, 56 patients were prostitutes. Forty-seven specimens obtained from female non-prostitutes who attended the Department of Obstetrics and Gynecology, Saitama Medical School, Japan during the period from 1993 to 1995 were also used in this study. DNA was extracted from these specimens and typing of C. trachomatis serovars was performed by the polymerase chain reaction-restriction fragment length polymorphism method. The identified serovars among prostitutes of Thailand (n = 56) /non-prostitutes of Thailand (n = 15) /non-prostitutes of Japan (n = 47) were as follows: Ba 1/0/2, D 8/1/15, E 11/2/8, F 16/9/8, G 4/0/7, H 3/2/3, I 1/0/1, J 3/0/0, and K 10/1/4. Serovar F was most prevalent (35.2%) in both prostitutes and non-prostitutes from Thailand, followed by serovar E (18.3%). On the other hand, serovar D was the most frequent serovar in non-prostitutes in Japan (31.9%) followed by serovars F (17.0%) and E (17.0%). A difference in the distribution of C. trachomatis serovars of Thailand and Japan was noted.

The full-length cDNA sequence for metalloprotease (MEP) of Arthroderma gypseum (one of the teleomorphs of the Microsporum gypseum complex) was determined by the 5´-rapid amplification of cDNA ends (RACE) and 3´-RACE methods using cDNA as a template. The full-length cDNA sequence of the MEP (2,670 bp) gene was proved to encode 677 amino acids. The amino acid sequence of the A. gypseum MEP gene shared about 89 and 66% sequence similarity with the conserved region of the Microsporum canis MEP gene and Aspergillus fumigatus, respectively. Southern hybridization analysis of genomic DNA with an MEP probe gave many distinct bands in BamHI, EcoRI and HindIII digests of genomic DNA from A. gypseum. Reverse transcriptase-PCR analysis suggested that keratin might stimulate the expression of MEP mRNA in A. gypseum.

Candida spp. are recognized as a leading contributor to mortality and morbidity in patients with onco-hematological malignancies. The rates and risk factors for mycotic infections in pediatric oncology patients are undetermined, particularly for those treated at centers in developing countries. The objective of the present study was to prospectively evaluate the species stratification and antifungal susceptibility profile of Candida spp. associated with superficial and systemic infection in children with onco-hematological diseases. Acute lymphoblastic leukemia was the most common underlying disease (71.4%) among the 91 children under study. Candida albicans was the predominant species, with 17/29 isolates (58.6%); followed by C. tropicalis, with 10/29 isolates (34.5%). The drug susceptibility data analysis for the clinical isolates of Candida revealed 17.2% (5/29) resistance to fluconazole. This study reinforces the need for the systematic surveillance of candidosis for the correct management of such life-threatening infections.

We investigated the prevalence and genotypic distribution of GBvirus-C/hepatitis G virus (GBV-C/HGV) and TT virus (TTV) in blood donors, mentally retarded children and four groups of patients living in Eastern Anatolia, Turkey. The prevalence and genetic analysis of TTV were determined by using the primers of the UTR and ORF1 regions of TTV, respectively. Reverse transcription nested (RT-n)-PCR was used to amplify 5´ UTR of GBV-C/HGV. Genotyping of HGV was carried out by PCR-based genotyping assay while RFLP was conducted to determine the genotypes of TTV. TTV DNA was detected in 118 of 410 sera tested, giving an overall prevalence of 28.7%; GBV-C/HGV-RNA was detected in only 17 cases, giving an overall prevalence of 4.1%. No significant differences were observed in the number of positive or negative tests for GBV-C/HGV and TTV according to duration of illness or mean duration of institutionalization in any of the groups studied. Although all samples from the study population belonged to genotypes 1 and 4, the most common TTV genotype is G2. In conclusion, our results indicate a low endemicity of GBV-C/HGV and TTV infection in Eastern Anatolia, Turkey. The presence of G2 strains reveals the limited genetic diversity of the GBV-C/HGV circulating in Turkey. We suggest that TTV infection of genotypes 1 and 4 is prevalent in the same region.

Antibiotic resistance among Gram-negative rods (GNRs) causing hospital-acquired infections poses a threat, particularly to intensive care unit (ICU) patients. This study was undertaken in order to achieve the following: to detect the frequency of GNRs isolated from coronary and surgical ICUs at the Institute of Cardiology, Istanbul University, between January 2000 - December 2002; to compare the resistance of these GNRs to selected antibiotics; and to determine the prevalence of extended-spectrum beta-lactamases (ESBLs). A total of 367 isolates were obtained from 171 patients. Susceptibility testing and detection of ESBLs were performed using the E-test method. Ceftazidime-clavulanate was used for the detection of ESBLs. The majority of microorganisms were isolated from the respiratory tract (45.5%) and blood (36.7%). Acinetobacter baumannii was the most frequently isolated GNR (24.5%), followed by Pseudomonas aeruginosa (22%). ESBL positivity was found to be 21.1%. High rates of the ESBLs of Escherichia coli and Klebsiella pneumoniae were observed, i.e., 27.7 and 57.5%, respectively. High rates of resistance to all antibiotics studied were observed. The most active agent against the majority of the isolates was imipenem (79.2%), followed by levofloxacin (77%) and ciprofloxacin (71%).

Shigella spp. isolated from diarrheal patients and non-diarrheal carriers were examined by PCR for the presence of two pathogenic genes, chromosomal ipaH and invasive plasmid encoded ial. Shigella spp. were detected in 7 of 72 diarrheal cases examined (9.7%), and 9 of 145 non-diarrheal cases (6.2%). All isolates from diarrheal cases harbored both ipaH and ial, while all isolates from non-diarrheal cases were positive for ipaH but not ial. These results suggested that Shigella spp. in healthy carriers were basically non-pathogenic.

Candida dubliniensis is a novel Candida spp. that is similar to Candida albicans with respect to several phenotypic characteristics. However, they differ from each other with respect to epidemiology, pathogenesis, and the rapid development of resistance to fluconazole. In the present study, we used a single-enzyme PCR-restriction fragment length polymorphism (RFLP) technique to differentiate C. dubliniensis from C. albicans. The amplified ITS region of C. dubliniensis was digested once using the enzyme B1nI, whereas that of C. albicans remained intact. All standard strains tested were identified successfully by this method. None of 140 clinical isolates identified morphologically as C. albicans were recognized as C. dubliniensis based on their PCR-RFLP pattern. Our PCR-RFLP method easily differentiated C. dubliniensis from C. albicans, and this result was also demonstrated with standard strains.

All cases of cholera that have occurred at our center in north India have been due to Vibrio cholerae O1 serotype Ogawa, including the outbreaks in 2002 and 2004. Here we report the emergence of V. cholerae O1 biotype El Tor serotype Inaba for the first time in this region since July 2004. Fifteen Inaba isolates were obtained from 32 patients suffering from cholera-like illness. The patients lived in Chandigarh and the neighboring states of Punjab, Haryana, and Himachal Pradesh. All strains were resistant to nalidixic acid and trimethoprim, and showed moderate sensitivity to amoxycillin. All were sensitive to ciprofloxacin, tetracycline, cefotaxime, amikacin, and gentamicin. All strains were found to be toxigenic when tested with a commercial reverse passive latex agglutination kit. The last reported Inaba isolate dominance in India was observed in Calcutta in 1989. There is a need to closely watch the spread of serotype Inaba, as it may cause outbreaks in other parts of India; molecular studies are warranted to understand the widespread emergence of Inaba in north India.

We have developed a surveillance system that can detect a severe acute respiratory syndrome (SARS) outbreak in a hospital as quickly as possible using the “SARS alert” strategy proposed by the World Health Organization (WHO). Our research examined hospital staff and in-patients during the winter of 2003/2004. We defined patients with a fever of over 38°C and respiratory symptoms as “cases with acute respiratory symptoms.”During the study period, 215 such cases (78% in-patients; 22% hospital staff members) were reported. A rapid diagnostic test for influenza was performed on 131 individuals, with 52 having positive results. There were no cases fulfilling the definition of SARS provided by the WHO in their SARS alert. The present surveillance system will be of use in the early detection of a SARS epidemic in a hospital as well as in early detection of similar illnesses accompanied by acute respiratory symptoms, such as influenza.

We have isolated and cloned the full-length nucleotide sequence of the hepatitis B virus (HBV) genome (denoted HBV-IM806-2) recovered from a Japanese patient with chronic hepatitis. This patient had a history of travel to Bangkok, Thailand, and then suffered the onset of acute hepatitis B 3 months after his return to Japan. The HBV-IM806-2 isolate was composed of 3,215 nucleotides and showed the highest similarity to genotype H of HBV. Interestingly, 24 amino acid residues specific for genotype H were identified throughout the full genome sequence. Furthermore, phylogenetic analysis based on the full genome sequence confirmed that IM806-2 belonged to genotype H and was more closely related to the prototype of the Los Angeles strain than to the Nicaragua strain.

Actinomycosis is an uncommon disease in children and most cases are cervicofacial infections. To date, there have been only a few reports on children with chest wall involvement due to actinomycosis. Here we report a 9-year-old girl with a mass lesion in the chest wall mimicking Ewing’s sarcoma of the rib. Thoracic actinomycosis without typical features of the disease is often evaluated with the suspicion of neoplasia. This rare entity should be considered in the differential diagnosis of mass lesions of the chest wall in children. The disease responds well to penicillin treatment.

A new convenient molecular typing method, simultaneous polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis, for three different genes of methicillin-resistant Staphylococcus aureus (MRSA) was evaluated using 35 isolates of MRSA and comparing results with those previously reported for sequencing-based spa typing. Twenty-nine isolates of the most frequent protein A (spa) type were discriminated into 6 different types by PCR-RFLP. In contrast, spa typing could discriminate only 1 of the 19 most frequent PCR-RFLP-type isolates. The discriminatory powers of the two methods were equal for the other isolates. These results suggest that PCR-RFLP has the advantages of both relative easiness and greater discriminatory power than spa typing. We also report the case of a suspected outbreak in which PCR-RFLP was sufficient for ruling out the possibility of an outbreak. Thus, PCR-RFLP is preferable as a preliminary screening method for epidemiological studies of nosocomial infection caused by MRSA.