Is methicillin-resistant Staphylococcus aureus a common pathogen in ventilation-associated pneumonia?: The experience of a tertiary teaching hospital in Jordan

Bacteriological Profile of Nosocomial Pneumonia and Current State of Antibiotic Resistance in the Military Hospital of Avicenne

This retrospective study, conducted over five years, aimed to assess the bacteriological profile of nosocomial pneumonia, the antibiotic resistance of isolated bacteria, and changes in these parameters over time. The analysis reviewed 660 samples from the microbiology department at the Military Hospital of Avicenne in Marrakech, Morocco, covering the period from January 1, 2017, to December 31, 2021. Among these samples, 303 microorganisms were identified from 251 specimens, confirming diagnoses of nosocomial pneumonia. Microorganism identification and antibiograms were performed using the Phoenix100 automated system from Becton Dickinson. The results revealed that 73% of the isolated microorganisms were Gram-negative bacilli, with Acinetobacter baumannii (29.4%) being the most common, followed by Enterobacteriaceae (28%), particularly Klebsiella pneumoniae (15.5%) and Pseudomonas aeruginosa (10.9%). Gram-positive cocci made up 22.5% of isolates, with Staphylococcus aureus (15.2%) being the most prevalent, while yeasts were present in 3.6% of cases. A polymicrobial nature was observed in 19.12% of samples. A. baumannii strains showed high resistance to most antibiotics, with an imipenem resistance rate of 88.5%; colistin was the only effective agent against these strains. In contrast, P. aeruginosa exhibited broad sensitivity to antibiotics, with only an 11.1% resistance rate to ceftazidime and good sensitivity to imipenem (80%). Extended-spectrum beta-lactamase production was noted in 11.5% of Enterobacteriaceae, mainly K. pneumoniae. Methicillin-resistant S. aureus prevalence was low at 11.6%, and all S. aureus strains were vancomycin-sensitive. The study highlights the importance of prudent antibiotic use, enhanced hospital hygiene practices, and ongoing monitoring of bacterial resistance. These measures are vital for developing therapeutic strategies suited to local epidemiology and reducing infections caused by multidrug-resistant microorganisms.

Staphylococcus aureus epidemiology, pathophysiology, clinical manifestations and application of nano-therapeutics as a promising approach to combat methicillin resistant Staphylococcus aureus

Staphylococcus aureus is a Gram-positive bacterium and one of the most prevalent infectious disease-related causes of morbidity and mortality in adults. This pathogen can trigger a broad spectrum of diseases, from sepsis and pneumonia to severe skin infections that can be fatal. In this review, we will provide an overview of S. aureus and discuss the extensive literature on epidemiology, transmission, genetic diversity, evolution and antibiotic resistance strains, particularly methicillin resistant S. aureus (MRSA). While many different virulence factors that S. aureus produces have been investigated as therapeutic targets, this review examines recent nanotechnology approaches, which employ materials with atomic or molecular dimensions and are being used to diagnose, treat, or eliminate the activity of S. aureus. Finally, having a deeper understanding and clearer grasp of the roles and contributions of S. aureus determinants, antibiotic resistance, and nanotechnology will aid us in developing anti-virulence strategies to combat the growing scarcity of effective antibiotics against S. aureus.

Effects of low-frequency ultrasound combined with anti-MRSA agents on the mouse model of pulmonary infection

The treatment of methicillin-resistant Staphylococcus aureus (MRSA)-induced pneumonia with antibiotics alone poses considerable challenges. To address these challenges, low-frequency ultrasound (LFU) emerges as a promising approach. In this study, a mouse pneumonia model was established through intratracheal injection of MRSA to investigate the therapeutic efficacy of LFU in combination with antibiotics. Minimal inhibitory concentration was assessed, and the distribution of antibiotics in the lung and plasma was determined using liquid chromatography coupled with mass spectrometry. Various parameters, including the survival rate, histopathology, lung bacterial clearance, and the expressions of cytokines and inflammation-related genes, were evaluated before and after treatment. Compared with the infection group, both the antibiotic-alone groups [vancomycin (VCM), linezolid, and contezolid (CZD)] and the groups in combination with LFU demonstrated an improvement in the survival status of mice. The average colony-forming units of lung tissue in the LFU combination groups were lower compared with the antibiotic-alone groups. While no significant changes in C-reactive protein and procalcitonin in plasma and bronchoalveolar lavage fluid were observed, histopathological results revealed reduced inflammatory damage in LFU combination groups. The secretion of interleukin-6 and tumor necrosis factor-alpha was decreased by the combination treatment, particularly in the VCM + LFU group. Furthermore, the expressions of MRSA virulence factors (hla and agrA) and inflammation-related genes (Saa3, Cxcl9, and Orm1) were further reduced by the combinations of LFU and antibiotics. Additionally, LFU treatment facilitated the distribution of VCM and CZD in mouse lung tissue at 30 and 45 min, respectively, after dosage.IMPORTANCETreating pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) with antibiotics alone poses significant challenges. In this in vivo study, we present compelling evidence supporting the efficacy of low-frequency ultrasound (LFU) as a promising approach to overcome these obstacles. Our findings demonstrated that LFU enhanced the effectiveness of vancomycin, linezolid, and contezolid in an MRSA pneumonia model. The combination of LFU with anti-MRSA agents markedly improved the survival rate of mice, accelerated the clearance of pulmonary bacteria, reduced inflammatory injury, inhibited the production of MRSA endotoxin, and enhanced the distribution of antibiotics in lung tissue. The application of LFU in the treatment of pulmonary infections held substantial significance. We believe that readers of your journal will find this topic of considerable interest.

Risk factors of multidrug-resistant bacteria infection in patients with ventilator-associated pneumonia: A systematic review and meta-analysis

BACKGROUND

Multidrug-resistant (MDR) bacteria-induced VAP often has high lethality. We present this systematic review and meta-analysis to assess the risk factors for MDR bacterial infection in patients with VAP.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Library were searched for studies regarding MDR bacterial infection in VAP patients, from Jan 1996 to Aug 2022. Study selection, data extraction, and quality assessment of included studies were conducted by two reviewers independently, and potential risk factors for MDR bacterial infection were identified.

RESULTS

Meta-analysis showed that the score of the Acute Physiology and Chronic Health Evaluation II (APACHE-II) [OR = 1.009, 95% (CI 0.732, 1.287)], Simplified Acute Physiology Score II (SAPS-II) [OR = 2.805, 95%CI (0.854, 4.755)], length of hospital-stay before VAP onset (days) [OR = 2.639, 95%CI (0.387, 4.892)], in-ICU duration [OR = 3.958, 95%CI (0.894, 7.021)], Charlson index [OR = 1.000, 95%CI (0.889, 1.111)], overall hospital-stay [OR = 20.742, 95%CI (18.894, 22.591)], Medication of Quinolones [OR = 2.017, 95%CI (1.339, 3.038)], medication of carbapenems [OR = 3.527, 95%CI (2.476, 5.024)], combination of more than 2 prior antibiotics [OR = 3.181, 95%CI (2.102, 4.812)], and prior use of antibiotics [OR 2.971, 95%CI (2.001, 4.412)] were independent risk factors of MDR bacterial infection in VAP patients. Diabetes and mechanical ventilation duration before VAP onset showed no association with risk for MDR bacterial infection.

CONCLUSIONS

This study has identified 10 risk factors associated with MDR bacterial infection in VAP patients. Identification of these factors would be able to facilitate the treatment and prevention of MDR bacterial infection in clinical practice.

The impact of COVID-19 pandemic on healthcare associated infections: A teaching hospital experience

Coronavirus disease-19 (COVID-19) is a global pandemic, with a high capability of contagious distribution, where national secondary and co-infections characterization are lacking. The objective of this study was to assess the impact of the COVID-19 pandemic on infection rates among patients admitted to the intensive care units at King Abdullah University Hospital, profiling the drug resistance rates nationally. This is a cross-sectional study of COVID-19 associated infections that was conducted at a teaching hospital, in the north of Jordan. It included all COVID-19 patients who were admitted to intensive care units during the first and second pandemic waves. Data on age, gender, length of stay, co-morbidities, co-infections and sensitivity to antibiotics were retrospectively collected from the hospital information database. Statistical analyses were performed using SPSS software. A total of 589 COVID-19 patients were included, of whom 20% developed bacterial associated infections. The ratio of bacterial co-infection to secondary infections was 1:8. Gram-negative bacteria, Acinetobacter baumannii (40.1%), Eschericia coli (17.5%), Klebsiella pneumonia (6.8%), and Pseudomonas aeruginosa (5.1%) were the most abundant isolated species. The detection rates of E coli (ESBL), K pneumonia (ESBL), A baumannii (CRO), P aeruginosa (CRO), S aureus (MRSA) were 52%, 67%, 97%, 44%, and 67%, respectively.