Discussion

In this study, we compared the incidence of HAI during the first 2 years of the COVID-19 pandemic with the 2 previous years. HAIs are a quality-of-care marker in different settings with well-established preventive measures. During the pandemic, many hospitals faced overburdened healthcare services, and conversions led to suboptimal care of non–COVID-19 patients in ambulatory and in-hospital settings. Hospitals faced an enormous challenge trying to accomplish preventive policies for HAI, partly due to the lack of medical supplies in some settings, understaffing, and overworked healthcare personnel, which together probably had a substantial impact on the increase of HAIs. ^{Reference Gaspar, Ferreira and Feliciano7}

The clinical and demographic characteristics of cases described in this cohort during the pandemic included those described repeatedly in multiple studies: older age, diabetes mellitus, hypertension, and overweight. We analyzed specific cancer-related characteristics and found that active cancer was more common during the pandemic. This difference has been linked to multiple factors, such as fear of patients going to the hospital, reduced medical attention in many in-hospital and outpatient services, and some hospitals converted exclusively for COVID-19 attention. ^{Reference Onesti, Tagliamento and Curigliano8–Reference Sud, Jones and Broggio10}

In this study, for the whole group, nosocomial pneumonia increased in patients during the pandemic period. When we analyzed this period, the nosocomial pneumonia rate was higher in non–COVID-19 patients; contrary to what occurred in patients with COVID-19, in whom VAP was significantly more frequent, as has been reported in multiple studies. ^{Reference Grasselli, Scaravilli and Mangioni11} VAP in COVID-19 patients was not only related to prolonged stays in the ICU and mechanical ventilation. Still, it was also associated with microaspirations, partly caused by prone positioning and acute respiratory distress syndrome, more steroid use, higher cumulative dosages, and more frequent use of JAK inhibitors. ^{Reference Grasselli, Scaravilli and Mangioni11} These factors favor impairment of immune cell function, damage to the alveolar membrane, and dysbiosis of the respiratory and digestive microbiota. ^{Reference Baccolini, Migliara and Isonne12,Reference Rouzé, Saura and Nseir13} In addition, several infection control measures for nosocomial pneumonia and VAP were not consistently followed in patients requiring intubation and pronation, in addition to overcrowding the ICU and converting different hospital wards into critical care units. ^{Reference Baccolini, Migliara and Isonne12}

In contrast, higher compliance with hand hygiene, environmental cleaning, patient isolation, and PPE during the pandemic probably helped maintain similar CDI and CLABSI rates in both periods. ^{Reference Baccolini, Migliara and Isonne12,Reference McMullen, Smith and Rebmann14} These findings also were observed in our series, in which CDI was not different between study periods; in fact, secondary BSI was lower during the pandemic periods (14.8%) in comparison to the prepandemic period (32.3%; P = .01).

In the first months of the COVID-19 pandemic, there was an excessive prescription of antimicrobials, particularly fluoroquinolones and third-generation cephalosporins. These were reported in 70%–74% of cases, mainly in those patients who developed the severe form of the disease, even in the absence of microbiologic isolation or strong suspicion of bacterial infection. ^{4,Reference Langford, So and Raybardhan15–Reference Rodríguez-Baño, Rossolini and Schultsz17} Approximately 8% of COVID-19 patients were diagnosed with secondary infections, which were more frequent in the ICU (8%–14%) compared with patients from other wards (4%–6%). ^{Reference Rodríguez-Baño, Rossolini and Schultsz17} In our study, we found elevated use of antibiotics, with no difference between periods (89% in the prepandemic period and 87.6% in the pandemic period), probably related to the type of patients treated at our hospital, with different levels of immunosuppression and neutropenia, in whom antibiotics are started empirically.

Gram-negative isolates are the microorganisms most frequently isolated in COVID-19 patients with secondary infections. ^{Reference Nasir, Rehman and Omair16,Reference Kumar, Adams and Hererra18,Reference Sang, Xi and Lin19} Other reports have described Acinetobacter baumannii and MRSA as frequent pathogens. ^{Reference Sang, Xi and Lin19,Reference Bentivegna, Luciani, Arcari, Santino, Simmaco and Martelletti20} We identified an increase in the isolation of E. coli, S. maltophilia, and S. aureus.

Increases in MDROs has been described in several reports during the COVID-19 pandemic as pathogens associated with HAIs: 75.5% in CR–K. pneumoniae, 91.2% in CR–A. baumannii, and 50% in MDR- S. maltophilia,. ^{Reference Lai, Chen, Ko and Hsueh21} In this study, we found no essential change in bacterial resistance between the 2 periods, except for ESBL–E. coli (60.9% in the pandemic period versus 58.5% in the prepandemic period; P = .05). Also, bacteria that had never been isolated in our hospital as a cause of VAP were identified, including Chryseobacterium indologenes and C. gleum, which were isolated only in patients with COVID-19.

Fungal infections, especially Aspergillus spp and Candida spp, have been associated with COVID-19. ^{Reference Lai, Chen, Ko and Hsueh21,Reference Bardi, Pintado and Gomez-Rojo22} In this study, the isolation of Aspergillus spp was documented in 4.8% of patients, without differences in the 2 periods; This rate was lower than those of other reports in Mexico during the first months of the pandemic, with prevalences between 9.7% and 19.3%. ^{Reference Roman-Montes, Martinez-Gamboa and Diaz-Lomelí23,Reference Vélez Pintado, Camiro-Zúñiga and Aguilar Soto24} Candida spp were also less frequent as a cause of infection (3.1%) than in other reports (14.4%). ^{Reference Segrelles-Calvo, de S Araújo and Llopis-Pastor25}

The overall 30-day mortality was 34.6%, similar to that described in other studies during the pandemic (30%–40%). ^{Reference Nasir, Rehman and Omair16,Reference Bardi, Pintado and Gomez-Rojo22} But when we divided the patients seen during the pandemic with or without COVID-19, the mortality rate was significantly higher among patients with COVID-19 infection (62.9%). This could have been related to neoplasm; 39.2% of patients were in cancer progression or relapse and 46% had recently been diagnosed and were starting the cancer treatment.

This study had several limitations. Data were collected only in a single institution. Because it is an oncological center, the general mortality may have been higher than that reported in other series. Due to its retrospective nature and the emergency of COVID-19, some information bias probably occurred. Nevertheless, this series has provided a local view of conditions before the COVID-19 pandemic and throughout the first 2 years of the pandemic at an oncological hospital that functioned hybrid from the beginning of the pandemic.

In this study, we showed that although hospital functioning was significantly disrupted by the need to care for COVID-19 patients, the number of patients with newly diagnosed cancer did not decrease.

In summary, in patients with cancer, nosocomial pneumonia was more frequent during the pandemic, and VAP was more frequent in patients with COVID-19. We detected an increase in the isolation of unusual bacteria during the pandemic, but the only significant MDR increase was documented for ESBL–E. coli. A regular review of surveillance data, continuous observation, and analysis of infection control policies and practices are critical for hospitals to identify gaps in prevention to address any increase in HAIs during emergencies like that posed by the ongoing COVID-19 pandemic.