Background Mechanical ventilation (MV) is often applied in critically ill patients in intensive care unit (ICU) to protect the airway from aspiration, and supplement more oxygen. MV may result in ventilator-associated pneumonia (VAP) in ICU patients. This study was to estimate the 90-day and 180-day mortalities of ICU patients with VAP, and to explore the influence of VAP on the outcomes of ICU patients. Methods Totally, 8182 patients who aged ≥18 years and received mechanical ventilation (MV) in ICU from Medical Information Mart for Intensive Care III (MIMIC III) database were involved in this study. All subjects were divided into the VAP group (n = 537) and the non-VAP group (n = 7626) based on the occurrence of VAP. Clinical data of all participants were collected. The effect of VAP on the prognosis of ICU patients was explored by binary logistic regression analysis. Results The results delineated that the 90-day mortality of VAP patients in ICU was 33.33% and 180-day mortality was 37.62%. The 90-day and 180-day mortality rates were higher in the VAP group than in the non-VAP group. After adjusting the confounders including age, ethnicity, heart failure, septicemia, simplified acute physiology score II (SAPSII) score, sequential organ failure assessment (SOFA) score, serum lactate, white blood cell (WBC), length of ICU stay, length of hospital stay, length of ventilation, antibiotic treatment, Pseudomonas aeruginosa (P.aeruginosa), methicillin-resistant Staphylococcus aureus (MRSA), other pathogens, the risk of 90-day and 180-day mortalities in VAP patients were 1.465 times (OR = 1.465, 95%CI: 1.188–1.807, P < 0.001) and 1.635 times (OR = 1.635, 95%CI: 1.333–2.005, P < 0.001) higher than those in non-VAP patients, respectively. Conclusions Our study revealed that ICU patients with VAP had poorer prognosis than those without VAP. The results of this study might offer a deeper insight into preventing the occurrence of VAP.

R-CHOP chemotherapy has been established as the first-line standard treatment for elderly patients diagnosed with diffuse large B-cell lymphoma. However, an increased risk of Pneumocystis jirovecii pneumonia in diffuse large B-cell lymphoma patients after the rituximab-based chemotherapy has been reported. We describe a case who developed intermittent cough, fever and shortness of breath after five cycles of R-CHOP treatment for diffuse large B-cell lymphoma. A rapid deterioration in patient’s respiratory condition prompted us to adopt an aggressive anti- Pneumocystis jirovecii pneumonia strategy that combined the conventional trimethoprim/sulfamethoxazole and another two antimicrobials, caspofungin and clindamycin. This is the first report mentioning the successful treatment of severe Pneumocystis jirovecii pneumonia with a triple-drug regimen in a HIV-uninfected patient. The aim of our report is also to emphasize that early and correct diagnosis of Pneumocystis jirovecii pneumonia in immunocompromised HIV-uninfected patients is very important. Relevant oncologists should be alert to the risk of Pneumocystis jirovecii pneumonia in patients receiving R-CHOP chemotherapy.