The association between mucosal microbiota and HIV-1 infection has garnered great attention in the field of HIV-1 research. Previously, we reported a receptor-independent HIV-1 entry into epithelial cells mediated by a Gram-negative invasive bacterium, Porphyromonas gingivalis. Here, we present evidence showing that P. gingivalis outer membrane vesicles (OMVs) promote mucosal transmission of HIV-1. We demonstrated, using the Dynabeads technology, a specific interaction between HIV-1 and P. gingivalis OMVs which led to an OMV-dependent viral entry into oral epithelial cells. HIV-1 was detected in human oral keratinocytes (HOKs) after a 20 minute exposure to the HIV-vesicle complexes. After entry, most of the complexes appeared to dissociate, HIV-1 was reverse-transcribed, and viral DNA was integrated into the genome of HOKs. Meanwhile, some of the complexes exited the original host and re-entered neighboring HOKs and permissive cells of HIV-1. Moreover, P. gingivalis vesicles enhanced HIV-1 infection of MT4 cells at low infecting doses that are not able to establish an efficient infection alone. These findings suggest that invasive bacteria and their OMVs with ability to interact with HIV-1 may serve as a vehicle to translocate HIV through the mucosa, establish mucosal transmission of HIV-1, and enhance HIV-1 infectivity.

Pathogenic bacteria and inflammatory factors in neonatal purulent meningitis (PM) were investigated to explore the diagnostic value of inflammatory factors in PM, to clarify the etiology, and to provide evidence for rational clinical treatment. Seventy-four neonates who were diagnosed with PM and were bacteriogically positive in Daqing Longnan Hospital from January 2012 to December 2015 were retrospectively analyzed and used as observation group. Another 74 neonates simultaneously hospitalized with non-PM factors were selected as control group. The levels of C-reactive protein (CRP) and β 2 microglobulin (β2MG) in cerebrospinal fluid in pediatric patients were measured, and the separation culture and identification of pathogenic bacteria were carried out at the same time. The results showed that i) neonatal PM often lacked specific clinical manifestations; ii) high risk factors of neonatal PM included gestational age, body weight <2,500 g, neonatal asphyxia, premature rupture of membranes, and umbilical or pulmonary infection; iii) the levels of CRP and β2MG in the cerebrospinal fluid in the neonatal PM group were significantly higher than those in the control group (P<0.05), and the neonatal PM group had obviously decreased levels of CRP and β2MG in the cerebrospinal fluid after treatment compared with those before treatment (P<0.05); iv) the positive rate of Gram-negative bacilli (G-bacilli) showed an increasing trend year by year in the past 4 years. Seventy-four strains of bacteria were isolated from the cerebrospinal fluid in neonatal PM group, including 45 strains of Gram-positive cocci (G+cocci, accounting for 60.81%) and 29 strains of G-bacilli (accounting for 39.19%). Among them, the top three were Escherichia coli, coagulase-negative staphylococci (CNS) and Streptococcus. These findings indicated that for suspected PM pediatric patients with high risk factors, the inflammatory factors in cerebrospinal fluid and the etiology should be investigated via lumbar puncture as early as possible to confirm the diagnosis. Pathogenic bacteria of meningitis mainly are Escherichia coli, CNS and Streptococcus, and the characteristics of pathogenic bacteria should be considered during experiential medication. The incidence rate of PM due to Streptococcus has an upward tendency and great damage, needing to arouse high attention in clinic.