Profile of infective microorganisms causing ventilator-associated pneumonia: A clinical study from resource limited intensive care unit

The biofilm formation and antibiotic resistance of bacterial profile from endotracheal tube of patients admitted to intensive care unit in southwest of Iran

Ventilator-associated pneumonia (VAP) is a prevalent nosocomial illness in mechanically ventilated patients. Hence, the aim of this study was to investigate the pattern of antibiotic resistance and biofilm formation of bacterial profiles from Endotracheal Tubes of patients hospitalized in an intensive care unit in southwest Iran. According to the standard operating method, the microbiological laboratory conducts bacteria culture and susceptibility testing on endotracheal Tube samples suspected of carrying a bacterial infection. The Clinical and laboratory standards institute (CLSI) techniques are used to determine the Antimicrobial resistance (AMR) of bacterial isolates to antibiotics using the disk diffusion method. The crystal violet staining method was used to assess the biofilm-forming potential of isolates in a 96-well microtiter plate. In total, (51%) GPBs were included in this study. The isolated GPB were coagulase-negative Staphylococcus (16%), S. aureus (14%). In total, (40%) of GNB were included in this study. The isolated GNB were Klebsiella spp. (36%), A. baumannii (22%), P. aeruginosa (35%). (32%) bacterial strains were MDR and (29%) strains were XDR. The results of biofilm formation showed (72%) were biofilm producers. VAP is a common and severe nosocomial infection in mechanically ventilated patients. Controlling biofilm formation, whether on the ET or in the oropharyngeal cavity, is thus an important technique for treating VAP. Colistin and linezolid are antibiotics that are effective against practically all resistant GNB and GPB isolates.

Oral Microbes in Hospital-Acquired Pneumonia: Practice and Research Implications

BACKGROUND

Hospital-acquired pneumonia accounts for 25% of all health care-associated infections and is classified as either ventilator-associated or non-ventilator-associated pneumonia. Hospital-acquired pneumonia most frequently results from aspiration of oropharyngeal secretions into the lungs. Although preventive measures for ventilator-associated pneumonia are well established, few preventive measures exist for the nonventilator type.

OBJECTIVE

To (1) explore oral microbes associated with ventilator-associated and non-ventilator-associated pneumonia in acutely ill, adult hospitalized patients, and (2) provide evidence-based recommendations for measures to prevent pneumonia in hospitalized patients.

METHODS

A literature search was conducted using CINAHL, Academic Search Premier, Medline, and the Cochrane Library.

RESULTS

Ten studies were found that identified common oral microbes in ventilator-associated and non-ventilator-associated pneumonia, including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, S aureus, and Streptococcus pneumoniae. Collectively, oral colonization with E coli, P aeruginosa, methicillin-resistant S aureus, and S aureus increased the risk of nonventilator pneumonia. Findings also suggested microaspiration of colonized oral microbes into the lungs. Non-ventilator-associated pneumonia had similar colonization rates of gram-positive and gram-negative bacteria, whereas ventilator-associated pneumonia had greater colonization with gram-negative bacteria. The literature did not indicate a standard of oral care effective in all patient populations.

DISCUSSION

Oral care is an effective intervention to prevent hospital-acquired pneumonia by reducing pathogenic oral microbial colonization. The impact of different methods and timing of oral care on oral microbes should be further explored, particularly in patients not receiving mechanical ventilation.

CONCLUSIONS

Findings reaffirm the importance of consistent oral care in hospitalized patients. In addition, practices should be different in patients receiving mechanical ventilation versus patients not receiving ventilation. Results may also provide knowledge to inform future preventive measures for pneumonia, particularly for nonventilator pneumonia.

The effect of different concentrations of chlorhexidine on microbial colonization: A double-blinded randomized controlled study

AIM

Study aims were to determine the most effective chlorhexidine concentration to be used in reducing microbial colonization in patients under mechanical ventilation and to examine the effect of oral care using different concentrations on the integrity of the oral mucous membranes.

DESIGN

This research was a randomized controlled double-blinded experimental study.

METHOD

The sample of study consisted of the 116 adult patients who remained intubated. Oral care was given to patients 4 times/day as per nurse protocol. Every morning during for 4 days, the intraoral mucosa of all groups of patients was assessed. Microbial colonization samples from oral mucosa were taken in the morning before oral care. A determination of the species of microorganisms in these samples was made.

RESULTS

A statistically significant difference was found with regard to the reproduction of microorganisms between the oral mucosa samples taken from patients using 2% and 1% chlorhexidine solutions (P < 0.001). In the cultures taken from patients on the first and fourth days of intubation, a total of 36 different microorganisms were seen to be reproducing.

CONCLUSION

It was concluded that the most effective oral solution for the prevention of microbial colonization in patients under mechanical ventilation was chlorhexidine 1%.

Severe COVID-19 Lung Infection in Older People and Periodontitis

Periodontal bacteria dissemination into the lower respiratory tract may create favorable conditions for severe COVID-19 lung infection. Once lung tissues are colonized, cells that survive persistent bacterial infection can undergo permanent damage and accelerated cellular senescence. Consequently, several morphological and functional features of senescent lung cells facilitate SARS-CoV-2 replication. The higher risk for severe SARS-CoV-2 infection, the virus that causes COVID-19, and death in older patients has generated the question whether basic aging mechanisms could be implicated in such susceptibility. Mounting evidence indicates that cellular senescence, a manifestation of aging at the cellular level, contributes to the development of age-related lung pathologies and facilitates respiratory infections. Apparently, a relationship between life-threatening COVID-19 lung infection and pre-existing periodontal disease seems improbable. However, periodontal pathogens can be inoculated during endotracheal intubation and/or aspirated into the lower respiratory tract. This review focuses on how the dissemination of periodontal bacteria into the lungs could aggravate age-related senescent cell accumulation and facilitate more efficient SARS-CoV-2 cell attachment and replication. We also consider how periodontal bacteria-induced premature senescence could influence the course of COVID-19 lung infection. Finally, we highlight the role of saliva as a reservoir for both pathogenic bacteria and SARS-CoV-2. Therefore, the identification of active severe periodontitis can be an opportune and valid clinical parameter for risk stratification of old patients with COVID-19.

Ventilator-associated pneumonia in patients with cancer: Impact of multidrug resistant bacteria

BACKGROUND

Patients with cancer have several risk factors for developing respiratory failure requiring mechanical ventilation (MV). The emergence of multidrug resistant bacteria (MDRB) has become a public health problem, creating a new burden on medical care in hospitals, particularly for patients admitted to the intensive care unit (ICU).

AIM

To describe risk factors for ventilator-acquired pneumonia (VAP) in patients with cancer and to evaluate the impact of MDRB.

METHODS

A retrospective study was performed from January 2016 to December 2018 at a cancer referral center in Mexico City, which included all patients who were admitted to the ICU and required MV ≥ 48 h. They were classified as those who developed VAP versus those who did not; pathogens isolated, including MDRB. Clinical evolution at 60-d was assessed. Descriptive analysis was carried out; comparison was performed between VAP vs non-VAP and MDRB vs non-MDRB.

RESULTS

Two hundred sixty-three patients were included in the study; mean age was 51.9 years; 52.1% were male; 68.4% had solid tumors. There were 32 episodes of VAP with a rate of 12.2%; 11.5 episodes/1000 ventilation-days. The most frequent bacteria isolated were the following: Klebsiella spp. [n = 9, four were Extended-Spectrum Beta-Lactamase (ESBL) producers, one was Carbapenem-resistant (CR)]; Escherichia coli (n = 5, one was ESBL), and Pseudomonas aeruginosa (n = 8, two were CR). One Methicillin-susceptible Staphylococcus aureus was identified. In multivariate analysis, the sole risk factor associated for VAP was length of ICU stay (OR = 1.1; 95%CI: 1.03-1.17; P = 0.003). Sixty-day mortality was 53% in VAP and 43% without VAP (P = 0.342). There was not higher mortality in those patients with MDRB.

CONCLUSION

This study highlights the high percentage of Gram-negative bacteria, which allows the initiation of empiric antibiotic coverage for these pathogens. In this retrospective, single center, observational study, MDRB VAP was not directly linked to increased mortality at 60 days.

Help, hinder, hide and harm: what can we learn from the interactions between Pseudomonas aeruginosa and Staphylococcus aureus during respiratory infections?

Recent studies of human respiratory secretions using culture-independent techniques have found a surprisingly diverse array of microbes. Interactions among these community members can profoundly impact microbial survival, persistence and antibiotic susceptibility and, consequently, disease progression. Studies of polymicrobial interactions in the human microbiota have shown that the taxonomic and structural compositions, and resulting behaviours, of microbial communities differ substantially from those of the individual constituent species and in ways of clinical importance. These studies primarily involved oral and gastrointestinal microbiomes. While the field of polymicrobial respiratory disease is relatively young, early findings suggest that respiratory tract microbiota members also compete and cooperate in ways that may influence disease outcomes. Ongoing efforts therefore focus on how these findings can inform more 'enlightened', rational approaches to combat respiratory infections. Among the most common respiratory diseases involving polymicrobial infections are cystic fibrosis (CF), non-CF bronchiectasis, COPD and ventilator-associated pneumonia. While respiratory microbiota can be diverse, two of the most common and best-studied members are Staphylococcus aureus and Pseudomonas aeruginosa, which exhibit a range of competitive and cooperative interactions. Here, we review the state of research on pulmonary coinfection with these pathogens, including their prevalence, combined and independent associations with patient outcomes, and mechanisms of those interactions that could influence lung health. Because P. aeruginosa-S. aureus coinfection is common and well studied in CF, this disease serves as the paradigm for our discussions on these two organisms and inform our recommendations for future studies of polymicrobial interactions in pulmonary disease.

Mechanical ventilator as a major cause of infection and drug resistance in intensive care unit

Ventilator-associated pneumonia (VAP) is the most frequent infection in intensive care units (ICU). It is associated with high rates of long morbidity and mortality. Management of a case of VAP is often said to add $40,000 to hospital costs USA. All these data directed our interest to study the etiology, risk factors, and antibiotic susceptibility patterns of VAP in ICU of Tanta University Hospital. This study included 36 cases of VAP. Endotracheal aspirates were obtained from all cases and microbiologically analyzed. Samples were collected over 1 year. Forty-two strains were isolated from 28 cases, while eight cases showed no bacterial growth. The most frequent organism was Staphylococcus aureus (30.95%), followed by Acinetobacter baumannii and Pseudomonas aeruginosa (21.43% for each), and the least common was Staphylococcus epidermidis (2.38%). Multi-drug resistance was detected in (50%) of the isolated bacteria in this study. Imipenem, amikacin, linezolid, vancomycin, and levofloxacin are recommended to be the most effective drugs in management of VAP. VAP is a serious problem in ICU carrying many risks for the patient live. Regimens of empirical treatment should take in consideration the update in the bacterial etiology and antibiotic susceptibility patterns of VAP.

Guidelines for the Evaluation and Treatment of Pneumonia

Pneumonia is a common cause of respiratory infection, accounting for more than 800,000 hospitalizations in the United States annually. Presenting symptoms of pneumonia are typically cough, pleuritic chest pain, fever, fatigue, and loss of appetite. Children and the elderly have different presenting features of pneumonia, which include headache, nausea, abdominal pain, and absence of one or more of the prototypical symptoms. Knowledge of local bacterial pathogens and their antibiotic susceptibility and resistance profiles is the key for effective pharmacologic selection and treatment of pneumonia.

Community analysis of dental plaque and endotracheal tube biofilms from mechanically ventilated patients

PURPOSE

Mechanically ventilated patients are at risk for developing ventilator-associated pneumonia, and it has been reported that dental plaque provides a reservoir of respiratory pathogens that may aspirate to the lungs and endotracheal tube (ETT) biofilms. For the first time, metataxonomics was used to simultaneously characterize the microbiome of dental plaque, ETTs, and non-directed bronchial lavages (NBLs) in mechanically ventilated patients to determine similarities in respective microbial communities and therefore likely associations.

MATERIAL AND METHODS

Bacterial 16S rRNA gene sequences from 34 samples of dental plaque, NBLs, and ETTs from 12 adult mechanically ventilated patients were analyzed.

RESULTS

No significant differences in the microbial communities of these samples were evident. Detected bacteria were primarily oral species (e.g., Fusobacterium nucleatum, Streptococcus salivarius, Prevotella melaninogenica) with respiratory pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcuspneumoniae, and Haemophilus influenzae) also in high abundance.

CONCLUSION

The high similarity between the microbiomes of dental plaque, NBLs, and ETTs suggests that the oral cavity is indeed an important site involved in microbial aspiration to the lower airway and ETT. As such, maintenance of good oral hygiene is likely to be highly important in limiting aspiration of bacteria in this vulnerable patient group.