Comparative multi-assay evaluation of Determine™ HIV-1/2 Ag/Ab Combo rapid diagnostic tests in acute and chronic HIV infection.

In resource-limited or point-of-care settings, rapid diagnostic tests (RDTs), that aim to simultaneously detect HIV antibodies and p24 capsid (p24CA) antigen with high sensitivity, can pose important alternatives to screen for early infections. We evaluated the performance of the antibody and antigen components of the old and novel version of the Determine™ HIV-1/2 Ag/Ab Combo RDTs in parallel to quantifications in a fourth-generation antigen/antibody immunoassay (4G-EIA), p24CA antigen immunoassay (p24CA-EIA), immunoblots, and nucleic acid quantification. We included plasma samples of acute, treatment-naïve HIV-1 infections (Fiebig stages I-VI, subtypes A1, B, C, F, CRF02_AG, CRF02_AE, URF) or chronic HIV-1 and HIV-2 infections. The tests' antigen component was evaluated also for a panel of subtype B HIV-1 transmitted/founder (T/F) viruses, HIV-2 strains and HIV-2 primary isolates. Furthermore, we assessed the analytical sensitivity of the RDTs to detect p24CA using a highly purified HIV-1NL4-3 p24CA standard. We found that 77% of plasma samples from acutely infected, immunoblot-negative HIV-1 patients in Fiebig stages II-III were identified by the new RDT, while only 25% scored positive in the old RDT. Both RDTs reacted to all samples from chronically HIV-1-infected and acutely HIV-1-infected patients with positive immunoblots. All specimens from chronically infected HIV-2 patients scored positive in the new RDT. Of note, the sensitivity of the RDTs to detect recombinant p24CA from a subtype B virus ranged between 50 and 200 pg/mL, mirrored also by the detection of HIV-1 T/F viruses only at antigen concentrations tenfold higher than suggested by the manufacturer. The RTD failed to recognize any of the HIV-2 viruses tested. Our results indicate that the new version of the Determine™ HIV-1/2 Ag/Ab Combo displays an increased sensitivity to detect HIV-1 p24CA-positive, immunoblot-negative plasma samples compared to the precursor version. The sensitivity of 4G-EIA and p24CA-EIA to detect the major structural HIV antigen, and thus to diagnose acute infections prior to seroconversion, is still superior.

Elevated prevalence of multidrug-resistant gram-negative organisms in HIV positive men.

BACKGROUND: Routes of transmission of multidrug-resistant gram-negative organisms (MDRGN) are not completely understood. Since sexual transmission of MDRGN might represent a potential mode that has not been noticed so far, this study evaluated transmission of MDRGN in HIV positive men. METHODS: Between November 2014 and March 2016, we retrospectively investigated the MDRGN prevalence in rectal swabs of n = 109 males tested positive for HIV (HP). These findings were compared to the MDRGN prevalence in n = 109 rectal swabs in age-matched males tested negative for HIV (HN) within the same period. According to the infection control protocol of University Hospital Frankfurt, Germany (UHF), patients admitted to intensive/intermediate care units have to be screened for MDRGN on day of admittance. Patients without HIV testing or MDRGN screening were excluded. RESULTS: MDRGN prevalence in rectal swabs was significantly higher (p = 0.002) in male HP (23.9%; 95% confidence interval 16.2-32.9%) than in age-matched male HN (8.3%; 3.8-15.1%). In total, 35 MDRGN species were detected. The most frequent MDRGN species was Escherichia coli with resistance due to ESBL expression and additional resistance to fluoroquinolones with n = 25/35 (71.4%; 53.7-85.4%). Thereof, n = 19/26 (73.1%; 52.2-88.4%) were detected in HP and n = 6/9 (66.7%; 29.9-92.5%) in HN, respectively. CONCLUSIONS: Prevalence of MDRGN is significantly higher in male HIV positive than in male HIV negative individuals. This might indicate sexual transmission of MDRGN within the male HIV positive population. As treatment options in case of MRGN infections are limited, prevention of MDRGN transmission is strongly emphasized.

Deficiency of immunity to poliovirus type 3: a lurking danger?

BACKGROUND: Europe was certified to be polio-free in 2002 by the WHO. However, wild polioviruses remain endemic in India, Pakistan, Afghanistan, and Nigeria, occasionally causing polio outbreaks, as in Tajikistan in 2010. Therefore, effective surveillance measures and vaccination campaigns remain important. To determine the poliovirus immune status of a German study population, we retrospectively evaluated the seroprevalence of neutralizing antibodies (NA) to the poliovirus types 1, 2 and 3 (PV1, 2, 3) in serum samples collected from 1,632 patients admitted the University Hospital of Frankfurt am Main, Germany, in 2001, 2005 and 2010. METHODS: Testing was done by using a standardized microneutralization assay. RESULTS: Level of immunity to PV1 ranged between 84.2% (95%CI: 80.3-87.5), 90.4% (88.3-92.3) and 87.5% (85.4-88.8) in 2001, 2005 and 2010. For PV2, we found 90.8% (87.5-90.6), 91.3% (89.3-93.1) and 89.8% (88.7-90.9), in the same period. Seroprevalence to PV3 was 76.6% (72.2-80.6), 69.8% (66.6-72.8) and 72.9% (67.8-77.5) in 2001 and 2005 and 2010, respectively. In 2005 and 2010 significant lower levels of immunity to PV3 in comparison to PV1 and 2 were observed. Since 2001, immunity to PV3 is gradually, but not significantly decreasing. CONCLUSION: Immunity to PV3 is insufficient in our cohort. Due to increasing globalization and worldwide tourism, the danger of polio-outbreaks is not averted - even not in developed countries, such as Germany. Therefore, vaccination remains necessary.