Whole-cell vaccine candidates induce a protective response against virulent Acinetobacter baumannii
Stephen J. Dollery, Daniel V. Zurawski, Ruth V. Bushnell, John K. Tobin, Taralyn J. Wiggins, David MacLeod, Naomi J. P. E. R. Tasker, Yonas A. Alamneh, Rania Abu-Taleb, Christine Czintos, Wanwen Su, Mariel G. Escatte, Heather N. Meeks, Michael J. Daly, Gregory J. Tobin
Abstract
Acinetobacter baumannii causes multi-system diseases in both nosocomial settings and a pre-disposed general population. The bacterium is not only desiccation-resistant but also notoriously resistant to multiple antibiotics and drugs of last resort including carbapenem, colistin, and sulbactam. The World Health Organization has categorized carbapenem-resistant A. baumannii at the top of its critical pathogen list in a bid to direct urgent countermeasure development. Several early-stage vaccines have shown a range of efficacies in healthy mice, but no vaccine candidates have advanced into clinical trials. Herein, we report our findings that both an ionizing γ-radiation-inactivated and a non-ionizing ultraviolet C-inactivated whole-cell vaccine candidate protects neutropenic mice from pulmonary challenge with virulent AB5075, a particularly pathogenic isolate. In addition, we demonstrate that a humoral response is sufficient for this protection via the passive immunization of neutropenic mice.