Serotypes and antimicrobial resistance of Salmonella enterica ssp in central Thailand, 2001-2006

This study was carried out to elucidate the epidemiological trends and antimicrobial susceptibilities against Salmonella serovars among Thai patients and asymptomatic carriers during 2001-2006 in central Thailand. A total of 1,401 human and 260 non-human isolates from various sources were included. The isolates were characterized using serotyping and antimicrobial susceptibility testing. The most common serovars in patients submitting stool samples were S. Weltevreden, S. Stanley, S. Anatum, and S. Rissen. Significantly higher odds ratios were observed in blood samples versus stool sample for S. Choleraesuis, S. Enteritidis, S. Typhimurium, and S. Typhi. Children under five years old suffered the most frequently from gastroenteritis. The patients most commonly infected with an invasive serovar were children and people from 26 to 55 years of age. Antimicrobial susceptibility data revealed that S. Schwarzengrund, S. Choleraesuis, S. Anatum, S. Stanley, S. Rissen, and S. Typhimurium were the most resistant serovars observed. The invasive serovar, S. Choleraesuis was resistant to cefotaxime and norfloxacin. Antimicrobial resistance to cefotaxime, was observed in S. Agona, S. Rissen, S. Typhimurium, S. Anatum, and S. Weltevreden. An alarmingly high frequency of resistance to third generation cephalosporins was observed. We recommend Thai authorities take action in order to prevent spread of resistant S. Choleraesuis and other serovars among animals and humans by enforcing a more strict policy on the use of antimicrobials in food animals.     

Lectin switching during dengue virus infection

Dengue virus receptors are relatively poorly characterized, but there has been recent interest in 2 C-type lectin molecules, dendritic cell-specific intercellular adhesion molecule 3 (ICAM-3)-grabbing nonintegrin (DC-SIGN) and its close homologue liver/lymph node-specific ICAM-3-grabbing integrin (L-SIGN), which can both bind dengue and promote infection. In this report we have studied the interaction of dengue viruses produced in insect cells, tumor cell lines, and primary human dendritic cells (DCs) with DC-SIGN and L-SIGN. Virus produced in primary DCs is unable to interact with DC-SIGN but remains infectious for L-SIGN-expressing cells. Skin-resident DCs may thus be a site of initial infection by insect-produced virus, but DCs will likely not participate in large-scale virus replication during dengue infection. These results reveal that differential glycosylation of dengue virus envelope protein is highly dependent on cell state and suggest that studies of virus tropism using virus prepared in insect cells or tumor cell lines should be interpreted with caution.     

Associations of MICB with cervical cancer in north-eastern Thais: identification of major histocompatibility complex class I chain-related gene B motifs influencing natural killer cell activation

The expression of MICB, a member of the major histocompatibility complex class I chain-related gene B family, is induced in response to cellular stress. It is one of the ligands to the NKG2D receptor. MICB is polymorphic, but the distribution of MICB polymorphism in north-eastern Thais and their potential associations with cancer have not yet been elucidated. In this study, polymerase chain reaction-sequence-specific primers were developed to identify 15 MICB alleles and one group of alleles. We performed MICB typing in 100 healthy north-eastern Thai females (NETF) and 99 cervical cancer patients to evaluate the association of MICB polymorphisms and the risk of developing cervical cancer. Eight and nine alleles were detected in the NETF and cervical cancer respectively. MICB*00502 was associated negatively with a corrected P-value of 0.0009, suggesting the existence of a protective allele in cervical cancer. Amino acid substitutions carried by this allele were investigated for their potential involvement in natural killer (NK) cell activation. Although lysine at amino acid position 80 (Lys80) and aspartic acid at position 136 (Asp136) were associated negatively with cervical cancer, only MICB carrying Asp136 could induce NK cell killing more efficiently than MICB-Lys80 when the NK cells were blocked by anti-NKG2D. This result suggested that aspartic acid at position 136 may affect NKG2D binding, leading to different degrees of immune cell activation.     

Effect of acupuncture on heart rate variability during prolonged high-intensity training in soccer players

Objective

To investigate the effects of acupuncture therapy compared with sham acupuncture on heart rate variability (HRV) in 24 elite soccer players during 4-week, high-intensity training sessions.

Association of polymorphic extracellular domains of MICA with cervical cancer in northeastern Thai population

Cancer of the cervix is one of the common cancers among women worldwide. The primary risk factor of cervical cancer is the high-risk group human papillomavirus infection. Host genetic factors should also be involved. Major histocompatibility complex class I chain related A (MICA), a ligand to the natural killer cell receptor group (NKG)2D receptor relevant to immune surveillance, was investigated as a potential candidate. MICA is highly polymorphic. Although the data were limited regarding functional polymorphism, it is conceivable that polymorphism of MICA may contribute to different degree of immune activation caused by different NKG2D-binding affinity, acting as a susceptible factor for development of cervical cancer. In this study, we have developed a polymerase chain reaction-sequence-specific primer technique defining most of MICA alleles with a total of 41 primer mixes. This set of primers could especially discriminate MICA*045 (formerly 052), a common allele in northeastern Thai population, from MICA*00701, a common allele in Caucasian population. Based on the distribution of MICA in northeastern Thai population, only 27 primer mixes were required to screen the MICA polymorphisms in this population. This set of primers was used for MICA typing of 100 samples of cervical cancer compared with 94 samples of healthy northeastern Thai females (NETF). Thirteen alleles or groups of alleles were identified in these samples. Common alleles in our population were MICA*00801(027,048)/0803, MICA*010 and MICA*00201(020, 023, 050)/30/41. Statistically significant differences were not observed in the distributions of MICA alleles between different stages of patients and the control group. However, there were particular residues that were negatively associated with cervical cancer, suggesting active MICA motifs in immune activation.