Banu Asima, Hassan Mir Mohammed Noorul, Anand Mridu, Srinivasa Sathyabheemarao
Bangalore Medical College and Research Institute.
Australas Med J. 2013 Jul 31;6(7):354-7. doi: 10.4066/AMJ.2013.1691. Print 2013.
Enteric fever is common in tropical regions and is caused by Salmonella enterica serotype typhi (S typhi ). For diagnosis of enteric fever, the Widal test is the most widely used test after blood culture. In HIV infected individuals false positive and false negative Widal reactions are common. The result is variable titres and baseline titres that are unusual in this patient population.
This study was done to determine the baseline antibody titres for S typhi among HIV infected individuals.
Average baseline antibody titres against O and H antigens of S typhi were measured by standard Widal test in 200 HIV positive asymptomatic individuals, as well as 200 age and sex-matched controls. The results were compiled and statistically analysed.
A total of 84 (42%) of the cases had an H antibody titre of >1:20 and 105 (52.5%) had a titre of >1:20 against O antigen. This implies that positive titre of H and O antigen is significantly associated with HIV positive cases with P<0.001. Correlation of CD4 count with antibody titres shows that there is no significant association between CD4 counts and antibody titres against either H (P=0.634) or O antigen (P=0.765).
This study shows that HIV infected individuals had increased titres of antibodies against S typhi from the baseline. This indicates a need for evaluation of current cut-off values of diagnostic titres for this group. We also suggest that it is best to perform baseline titres against S t yphi for each patient at the time of diagnosis of HIV status, and to use this for future reference.
肠热症在热带地区很常见，由伤寒沙门氏菌（伤寒杆菌）引起。对于肠热症的诊断，维达试验是血培养后使用最广泛的检测方法。在艾滋病毒感染者中，维达反应出现假阳性和假阴性很常见。其结果是滴度变化以及在该患者群体中不常见的基线滴度。
本研究旨在确定艾滋病毒感染者中伤寒杆菌的基线抗体滴度。
通过标准维达试验测量了200名艾滋病毒阳性无症状个体以及200名年龄和性别匹配的对照者针对伤寒杆菌O和H抗原的平均基线抗体滴度。对结果进行了汇总和统计分析。
共有84例（42%）的H抗体滴度>1:20，105例（52.5%）针对O抗原的滴度>1:20。这意味着H和O抗原的阳性滴度与艾滋病毒阳性病例显著相关，P<0.001。CD4细胞计数与抗体滴度的相关性表明，CD4细胞计数与针对H抗原（P=0.634）或O抗原（P=0.765）的抗体滴度之间无显著关联。
本研究表明，艾滋病毒感染者相对于基线水平，针对伤寒杆菌的抗体滴度有所升高。这表明需要评估该群体当前诊断滴度的临界值。我们还建议，在诊断艾滋病毒感染状态时，最好为每位患者检测针对伤寒杆菌的基线滴度，并将其用于未来参考。
