Epidemiology of Hospital Acquired Pneumonia
Epidemiology of Hospital Acquired Pneumonia
This project aimed at analyzing and assessing of the early and late Hospital-Acquired
 Pneumonia(HAP) bacterial pathogens and their resistance to antimicrobial agents. The
 incidence of their resistance to antimicrobial agent is assessed. Included are patients
 hospitalized in the Intensive Care Departments of cooperated University hospitals, who
 developed early or late HAP. Bacterial pathogens and their resistance to antibiotics are
 identified using standard microbiological methods. The patient's mortality with respect to
 their initial antibiotic therapy is statistically analyzed.
Introduction. Hospital-acquired pneumonia is one of the most frequent and most severe medical
 complications in patients hospitalized in intensive care units. It develops mainly in
 association with invasive airway management and mechanical ventilation. It is an important
 factor affecting health care economy and often related to bacterial resistance. Understanding
 the etiology of pathogens and their potential resistance to antimicrobial agents has a major
 impact on both patients' morbidity and mortality and the economic aspect of their treatment.
 Pneumonia is diagnosed by assessing clinical signs and detecting etiologic agents. Clinical
 signs are assessed especially by finding fresh or progressive infiltrates on chest
 radiographs, together with at least two other signs of respiratory tract infection. From the
 epidemiological point of view, pneumonia may be either community-acquired (CAP) or
 hospital-acquired (HAP). CAP is defined by developing in the community outside health care
 facilities and, if the patient is hospitalized, clinical manifestations within 48 h of
 hospital admission. HAP may be characterized as pneumonia developing 48 h or more after
 admission to a health care facility or within 14 days after discharge. More precise
 classification according to the time of the onset of clinical signs distinguishes early-onset
 (from 2 to 4 days after admission) from late-onset (from day 5 after admission) HAP. The most
 common pathogens causing CAP are Streptococcus pneumoniae, Chlamydophila pneumoniae and
 Mycoplasma pneumoniae. HAP is mostly caused by endogenous bacterial strains, originating from
 primary microflora or secondary colonizing bacteria with a higher level of resistance in the
 early- and late-onset forms, respectively. This knowledge is used to select the proper
 therapy since the proportion of individual pathogens determines the strategy of initial
 antibiotic treatment. Adequate antibiotic therapy is an important factor influencing the
 effectiveness of therapy and, of course, the patient's survival. The prospective study aimed
 at identifying etiologic agents of pulmonary inflammation in patients with the most severe
 forms of respiratory insufficiency requiring mechanical ventilation. The objectives were to
 describe the prevalence of respiratory tract pathogens, to determine their susceptibility to
 a range of tested antibiotic agents, and to acquire information on the proportion of
 resistant strains in the population of these pathogens. The impact of adequate antibiotic
 therapy was assessed, with respect to patient mortality and morbidity rates.

 Hypothesis. Most sever types of nosocomial bacterial pneumonias, required artificial lung
 ventilation are often exogenous. The infection source is transferred to patient´s airways
 from outsider during hospitalisation. The object of the research is bacterial agent direct
 recognition, its originality identification based on genome restrict fragment analysis.

 Material and Methods. The group comprised patients hospitalized in the Intensive Care
 Departments of cooperating hospitals between 1 May 2013 and 30 April 2015 who developed signs
 of HAP. Also included are patients with positive findings in their tracheal secretion on
 admission to the department if transferred from another ward of the hospital. In intubated
 patients, secretion samples for microbiology culture tests are obtained by aspiration from
 the lower airway. Mortality is statistically analyzed by Fisher's exact test. The clinical
 signs of pneumonia are defined as the presence of newly developed or progressive infiltrates
 on chest radiographs plus at least two other signs of respiratory tract infection:
 temperature >38 °C, purulent sputum, leukocytosis >10x103/mm3 or leukopenia <4x103/mm3, signs
 of inflammation on auscultation, cough and/or respiratory insufficiency with oxygenation
 index≤300 mm Hg. Each sample is processed by semiquantitative method based on the
 four-quadrant streak technique using a calibrated loop. The etiologic agent is considered
 relevant if cultured in the tracheal secretion at a enough quantity. Tracheal secretion
 samples are processed by traditional microbiological methods. The microorganisms are
 identified by biochemical dentification tests, and automated systems. The yeasts are
 identified using commercial kit. If an identical culture, determined as the etiologic agent,
 is repeatedly isolated from multiple samples obtained from the same patient, only the first
 isolated culture is included in the study. Susceptibility to antibiotics is determined by the
 standard microdilution method. Adequate initial therapy is defined as administrative of at
 least one antibiotic (suitable for treating pneumonia) shown in vitro to be effective against
 the isolated causative agent.

 Progress chart. The collection and processing of the patient´s microbiological samples at
 cooperatived clinic departments between 1 May 2013 and 30 April 2015 will be performed. The
 co-operative centers sent the samples to microbiological departments of their own hospitals
 and there the samples will processed and safed. Collected data will continuously to the
 central database be stored. The microbiological samples collection will finish 30 April 2015
 and between 1 May 2015 and 31 december 2015 the data will be analysed and assessed. The
 processing of the data allows express conclusions and prepare proposals to event. hygienical
 arrangement changes.

 Way of data acquiring. In intubated patients, secretion samples for microbiology culture
 tests were obtained by aspiration from the lower airway. The group comprise patients
 hospitalized in the Intensive Care Department of Hospitals, cooperated in study, between 1
 May 2013 and 30April 2015 who developed signs of HAP. Also included are patients with
 positive findings in their tracheal secretion on admission to the department if transferred
 from another ward of the hospital. Predicted number of patients is 300 (400 - 500 positive
 isolates). Considerate number is estimated according the pilot study. Predicted number of
 patients in all cooperated centers is about 15 per month. There the data analysis will be
 made with statistic normality test Shapiro-Wilk and Mann-Whitney U test. Computer program
 SPSS version 15 to statistic assessment will be used.

 Cooperation. The project is multicentric. There are cooperating Departments of Anesthesiology
 and Intensive Care Medicine in Olomouc, Brno, Hradec Kralove and Thomayer's Hospital Praha.
 The assessing of microbiological samples, collected from patients in this hospitals will be
 in microbiologic departments of this hospitals made.

 Discussion. Given the incidence of 51 cases out of a total of 508 patients hospitalized in
 the Department of Anesthesiology and Intensive Care Medicine Olomouc, Czech Republic, in
 2011, the prevalence (10%) was at the lower limit of the commonly reported range (9-24%). In
 agreement with the literature, most cases (86%) were late-onset HAP. Bacterial pathogens
 associated with the majority of deaths were strains of Klebsiella pneumoniae, Pseudomonas
 aeruginosa, Burgholderia cepacia komplex and Escherichia coli, more than 50% of which were
 multiresistant. In late-onset HAP, multiresistant strains accounted for as many as 58% of
 strains. In early onset HAP, the proportion of multiresistant strains could not been reliably
 assessed due to the small number of cases. The mortality rates in patients receiving adequate
 initial antibiotic therapy were 13% lower than in those treated with antibiotics to which
 isolated bacterial pathogens were later found to be resistant. According to Fiser's two-sided
 exact test, the resulting difference in mortality rates between the two studied groups is not
 significant (P=0.385), because of small set of data. Given the fact that despite adequate
 initial antibiotic therapy, the mortality rates were relatively high (9 out of 30 dead
 patients) and mortality is also likely to be influenced by the time of initiation of
 antibiotic therapy. In case of the mortality rates in patients with adequate therapy, our
 results (30%) are in agreement with those by Luna et al. who reported 38%. The same authors
 also found 91% mortality associated with inadequate therapy, a much higher rate than our
 results (43%). The difference, however, might be explained by a different epidemiological
 situation at bacterial resistance levels. HAP may be characterized as endogenous. Despite the
 high proportion of multiresistant strains, clonal spread was not confirmed, with the
 exception of Burgholderia cepacia komplex. Thus, secondary colonization of patient's
 microflora during hospitalization is likely.
Inclusion Criteria:

 -  The clinical signs of pneumonia are defined as the presence of newly developed or
 progressive infiltrates on chest radiographs plus at least two other signs of
 respiratory tract infection: temperature >38 °C, purulent sputum, leukocytosis
 >10x103/mm3 or leukopenia <4x103/mm3, signs of inflammation on auscultation, cough
 and/or respiratory insufficiency with oxygenation index PaO2/FiO2 ≤300 mm Hg.

 Exclusion Criteria:

 -  Pregnancy.

 -  The etiologic agent is considered relevant if cultured in the tracheal secretion at a
 quantity of >105 CFU/ml.

 -  Patients agreement absence.