Quantitative Culture Research Articles

Characterizing the urobiome in geriatric males with chronic indwelling urinary catheters: an exploratory longitudinal study.

The impact of chronic indwelling urinary catheters (IUCs) on the composition and stability of the urinary microbiota remains unknown. The primary aim of this study was to describe the urinary microbiomes of geriatric males with chronic IUCs. A secondary aim was to explore clinical catheter-associated urinary tract infection (CAUTI) courses of the participants. Geriatric male patients with chronic IUCs were followed longitudinally. Catheterized urine, catheter tips, and both urethral and periurethral swabs were collected from participants at monthly intervals. Microbes were isolated and identified from each specimen using an enhanced culture method called expanded quantitative urine culture (EQUC) and targeted 16S rRNA gene DNA sequencing. Microbial outcomes were examined both in the absence of urinary symptoms and in the context of clinical diagnosis of CAUTI. Ten male participants (mean age 86 years) were enrolled. Urinary microbiomes differed for each participant. However, within each individual, microbiomes were similar over time and across niches (bladder, catheter, urethra, and periurethra). Within-niche microbiomes differed across individuals, and this was observed over time. The most abundant bacteria isolated from all niches were known uropathogens. Six of 10 individuals met diagnostic criteria for CAUTI at least once during the 12-month observation period, but no evidence of this or antibiotic treatment/response was discernable in our monthly samples. The microbiomes of each participant were unique and remained similar over time and across niches. Longitudinal EQUC or 16S rRNA gene sequencing data could be useful to clinicians when diagnosing or treating possible CAUTI.IMPORTANCECatheter-associated urinary tract infections (CAUTIs) are serious but preventable nosocomial infections. The most common risk factor for developing CAUTI is prolonged use of indwelling urinary catheters (IUCs). This study provides the first longitudinal description of the urinary microbiomes of geriatric males with chronic IUCs, in the absence of urinary signs and symptoms, as a first step toward enhancing our knowledge of the impact of chronic IUCs on the composition and stability of the urinary microbiota. This is an understudied area, particularly for males.

Next generation sequencing identifies an increased diversity of microbes in post lavage specimens in infected TKA using a biofilm disrupting irrigant

BackgroundPeriprosthetic joint infection (PJI) is a devastating complication of joint arthroplasty. In chronic PJI, a biofilm envelops the surface of implants, which contains microbiota within an extra-microbial polymeric matrix (EMPM). Microbial identification is paramount for effective treatment. In this study, we use a multi-modal, EMPM disrupting, neoadjuvant irrigant and compare the microbiota detected pre-lavage to post-lavage by two techniques: culture and Next Generation Sequencing (NGS). We suspect more organisms to be identified after applying an EMPM disrupting irrigant. MethodsA multicenter, prospective study was conducted on 38 patients with known Total Knee Arthroplasty PJI. At initial arthrotomy, synovial fluid was obtained and analyzed for quantitative cultures and microbial NGS. Joint was then irrigated with Bactisure Lavage followed by Normal Saline. Post-lavage samples were similarly obtained and analyzed. ResultsIn pre-lavage samples for cultures, 55.3% of samples were positive, identifying 11 unique organisms. In post-lavage samples for cultures, 13.2% of samples were positive, identifying 5 unique organisms. In pre-lavage samples for NGS, 79% were DNA signal positive, identifying 126 unique organisms. In post-lavage samples for NGS, 74% of samples were DNA signal positive, identifying 177 unique organisms. Moreover, 135/177 of these organisms were not identified pre-lavage. ConclusionIn this pre-to-post irrigant study, culture showed a decrease in the number of identifiable organisms post-lavage. In contrast NGS revealed an increase in the number of identifiable organisms post-lavage. Furthermore, NGS identified 135 additional organisms, not detected pre-lavage. This suggests an increased diversity of microbes may exist within EMPM, which are not cultivable.

Comparison of Decontamination-Preservation Protocols for Delayed Surgical Re-implantation of Osteoarticular Fracture Fragments

Background: To avoid discarding contaminated, devascularized osteoarticular fragments required for joint reconstruction, fragments need to be decontaminated while preserving chondrocyte viability. We hypothesized that disinfection with povidone-iodine or chlorhexidine followed by preservation using the Missouri Osteochondral Preservation System (MOPS) would allow for effective decontamination while retaining essential chondrocyte viability in osteoarticular fracture fragments for up to 14 days of shelf-stable point-of-care storage. Methods: With IACUC approval, purpose-bred hounds (n=16) were humanely euthanized for unrelated purposes and subjected to captive bolt trauma to create open distal humeral fractures. For each elbow (n=32), humerus, radius and ulna tissues were recovered such that 96 contaminated, devascularized osteoarticular fragments were randomly allocated to one treatment: Betadine (n=42): saline irrigation (1L), immersion in 10% povidone-iodine (20 min), saline irrigation; Chlorhexidine (n=42): saline irrigation, immersion in 0.002% chlorhexidine gluconate (20 min), saline irrigation; Injured Control (n=12): no decontamination treatment. After 7 or 14 days in MOPS, tissues were assessed by quantitative microbial culture and Viable Chondrocyte Density (VCD) measures. Results: Captive bolt trauma consistently resulted in type 3 open articular fractures. Injured Control osteoarticular fragments produced high polymicrobial counts at days 7 and 14. Chlorhexidine treatment was effective for decontaminating fragments such that no CFUs for clinically relevant bacteria were produced, while Betadine treatment was not fully effective at decontamination. Chlorhexidine decontamination followed by MOPS preservation maintained VCD in osteoarticular tissues over the desired 70% mean for 14 days, whereas the Injured Control group was associated with significant loss of VCD (Day-7=59%, Day-14=13%), which was further exacerbated by Betadine treatment (Day-7=29%, Day-14=6%). Conclusion: Contaminated, devascularized osteoarticular fracture fragments can be effectively decontaminated while maintaining essential chondrocyte viability for 14 days after type 3 open articular fractures using a decontamination-preservation protocol that combines saline irrigation with 0.002% chlorhexidine immersion followed by shelf-stable point-of-care storage in MOPS.

A preclinical model for osteoarticular fracture fragment preservation for delayed re-implantation

BackgroundOpen articular fractures often include contaminated, devascularized osteoarticular fragments that are critical for joint reconstruction. Definitive treatment is often delayed such that decontamination and preservation of critical fragments for joint reconstruction is highly desirable. To validate decontamination and preservation protocols for safe and effective preservation of osteoarticular fragments for re-implantation, a preclinical animal model for inducing type 3 open articular fractures with contaminated, devascularized osteoarticular fragments was developed and validated. Materials and methodsWith IACUC approval, purpose-bred hounds (n = 5) were humanely euthanized. Immediately following euthanasia, a penetrating captive bolt pistol with 1.25 grain cartridge centered on the cranial aspect of each distal humerus was discharged to create open fractures in 3 dogs (6 elbows). In 2 dogs, matched osteoarticular tissues from non-injured elbows (controls) were retrieved for comparison. Distal humerus, proximal radius, and proximal ulna osteoarticular fragments (n = 27) were immediately placed in Missouri Osteochondral Preservation System (MOPS) solution and stored at room temperature. Radiographic, chondrocyte viability, and quantitative microbial culture assessments were performed immediately (time-0) and at 7 and 14 days of storage. ResultsThis preclinical canine model reliably produced type 3 open distal humeral fractures characterized by devascularized and contaminated osteoarticular fracture fragments. All fragments produced extensive microbial growth through 14 days of storage. Without decontamination, viable chondrocyte density in the fragments decreased significantly within 7 days, likely attributable to the profound contamination. ConclusionThese data highlight the importance of developing a reliable method for point-of-care decontamination and preservation of osteoarticular fracture fragments for safe and effective reimplantation of articular fracture fragments for joint reconstruction.

Transitions in lung microbiota landscape associate with distinct patterns of pneumonia progression.

The precise microbial determinants driving clinical outcomes in severe pneumonia are unknown. Competing ecological forces produce dynamic microbiota states in health; infection and treatment effects on microbiota state must be defined to improve pneumonia therapy. Here, we leverage our unique clinical setting, which includes systematic and serial bronchoscopic sampling in patients with suspected pneumonia, to determine lung microbial ecosystem dynamics throughout pneumonia therapy. We combine 16S rRNA gene amplicon, metagenomic, and transcriptomic sequencing with bacterial load quantification to reveal clinically-relevant pneumonia progression drivers. Microbiota states are predictive of pneumonia category and exhibit differential stability and pneumonia therapy response. Disruptive forces, like aspiration, associate with cohesive changes in gene expression and microbial community structure. In summary, we show that host and microbiota landscapes change in unison with clinical phenotypes and that microbiota state dynamics reflect pneumonia progression. We suggest that distinct pathways of lung microbial community succession mediate pneumonia progression.

Droplet Digital PCR for Acinetobacter baumannii Diagnosis in Bronchoalveolar Lavage Samples from Patients with Ventilator-Associated Pneumonia.

Advanced diagnostic technologies have made accurate and precise diagnosis of pathogens easy. Herein, we present a new diagnostic method, droplet digital PCR (ddPCR), to detect and quantify Acinetobacter baumannii in mini bronchoalveolar lavage (mini-BAL) samples. A. baumannii causes ventilator-associated pneumonia (VAP), a severe healthcare infection affecting patients' lungs. VAP carries a high risk of morbidity and mortality, making its timely diagnosis crucial for prompt and effective management. Methodology. The assay performance was evaluated by comparing colonization data, quantitative culture results, and different generations of PCR (traditional PCR and Real-Time PCR-qPCR Taqman® and SYBR® Green). The ddPCR and qPCR Taqman® prove to be more sensitive than other molecular techniques. Reasonable analytical specificity was obtained with ddPCR, qPCR TaqMan®, and conventional PCR. However, qPCR SYBR® Green technology presented a low specificity, making the results questionable in clinical samples. DdPCR detected/quantified A. baumanni in more clinical samples than other methods (38.64% of the total samples). This emerging ddPCR technology offers promising advantages such as detection by more patients and direct quantification of pathogens without calibration curves.

Antibiotic De-escalation Patterns and Outcomes in Critically Ill Patients with Suspected Pneumonia as Informed by Bronchoalveolar Lavage Results.

Antibiotic stewardship in critically ill pneumonia patients is crucial yet challenging, partly due to the limited diagnostic yield of noninvasive infectious tests. In this study, we report an antibiotic prescription pattern informed by bronchoalveolar lavage (BAL) results, where clinicians de-escalate antibiotics based on the combination of quantitative cultures and multiplex PCR rapid diagnostic tests. We analyzed data from SCRIPT, a single-center prospective cohort study of mechanically ventilated patients who underwent a BAL for suspected pneumonia. We used the novel Narrow Antibiotic Therapy (NAT) score to quantify day-by-day antibiotic prescription pattern for each suspected pneumonia episode etiology (bacterial, viral, mixed bacterial/viral, microbiology-negative, and non-pneumonia control). We also analyzed and compared clinical outcomes for each pneumonia etiology, including unfavorable outcomes (a composite of in-hospital mortality, discharge to hospice, or requiring lung transplantation during hospitalization), duration of ICU stay, and duration of intubation. Clinical outcomes were compared with the Mann-Whitney U test and Fisher's exact test. We included 686 patients with 927 pneumonia episodes. NAT score analysis indicated that an antibiotic de-escalation pattern was evident in all pneumonia etiologies except resistant bacterial pneumonia. Microbiology-negative pneumonia was treated similarly to susceptible bacterial pneumonia in terms of antibiotic spectrum. Over a quarter of the time in viral pneumonia episodes, antibiotics were completely discontinued. Unfavorable outcomes were comparable across all pneumonia etiologies. Patients with viral and mixed bacterial/viral pneumonia had longer durations of ICU stay and intubation. BAL quantitative cultures and multiplex PCR rapid diagnostic tests resulted in prompt antibiotic de-escalation in critically ill pneumonia patients. There was no evidence of increased incidence of unfavorable outcomes.

Nosocomial pneumonia

Nosocomial pneumonia is defined as pneumonia occurring ≥ 48 h after hospital admission in apatient without severe immunosuppression. It can occur in spontaneously breathing patients or with noninvasive ventilation (NIV) and mechanically ventilated patients. In patients with suspected ventilator-associated pneumonia (VAP) (semi)quantitative cultures of tracheobronchial aspirates or bronchoalveolar lavage fluid should be perfomed. The initial empirical antimicrobial treatment is determined by the risk for multidrug-resistant pathogens (MDRP). The advantage of combination treatment increases with the prevalence of MDRPs. The antibiotic treatment should be adapted when the microbiological results are available. After 72 h astandardized re-evaluation including the response to treatment and also checking of the suspected diagnosis of pneumonia in astructured form is mandatory. Treatment failure can occur as aprimary or secondary failure and in the case of primary progression necessitates another comprehensive diagnostic work-up before any further antibiotic treatment.

Synthetic antimicrobial peptides Bac-5, BMAP-28, and Syn-1 can inhibit bovine respiratory disease pathogens in vitro.

Mass treatment with antibiotics at arrival has been the mainstay for bovine respiratory disease (BRD) control but there is an increase in antimicrobial-resistant bacteria being shed from treated cattle. BRD is a disease complex that results from the interaction of viruses or bacteria and susceptible animals with inappropriate immunity. With bacteria being the only feasibly treatable agent and the emergence of antimicrobial resistance, decreased efficacy of commonly used antibiotics could threaten livestock health. There is a need for new antimicrobial alternatives that could be used to control disease. Naturally occurring antimicrobial peptides (AMP) have been proposed to address this need. Here we tested the effect of bovine myeloid antimicrobial peptide-28 (BMAP-28), a synthetic BMAP-28 analog Syn-1, and bactenecin 5 (Bac-5) on Mannheimia haemolytica (Mh) using a quantitative culture method and the broth microdilution method to determine minimum inhibitory and bactericidal concentrations (MIC and MBC). We also tested the antiviral effect of these AMP against bovine herpes-1 (BHV-1) and bovine respiratory syncytial virus (BRSV) using the Reed and Muench method to calculate the viral titers after treatment. We demonstrated that BMAP-28 and Syn-1 can inhibit Mh growth and BMAP-28 can inhibit replication of BHV-1 and BRSV. Moreover, we showed that BMAP-28 and Bac-5 can be used together to inhibit Mh growth. When used alone, the MIC of BMAP-28 and Bac-5 was 64 and 128 μg/mL respectively, but when applied together, their MIC ranged from 0.25-16 for BMAP-28 and 8-64 μg/mL for Bac-5, resulting in a decrease in concentration of up to 256 and 16-fold, respectively. The synergistic interaction between those peptides resulted in concentrations that could be well tolerated by cells. Our results demonstrate that bovine cathelicidins could be used as alternatives to antimicrobials against BRD pathogens. These findings introduce a path to discovering new antimicrobials and determining how these peptides could be tailored to improve cattle health.

Epidemiology and antimicrobial resistance trends of pathogens causing urinary tract infections in Mwanza, Tanzania: A comparative study during and after the implementation of the National Action Plan on Antimicrobial Resistance (2017-2022)

ObjectivesTo delineate the epidemiology and antimicrobial resistance (AMR) trends of pathogens causing urinary tract infections (UTIs) during (June 2019-June 2020) and after (March-July 2023) the implementation of the National Action Plan on AMR 2017-2022 in Mwanza, Tanzania. MethodsThis cross-sectional study was conducted among 2097 patients with clinical symptoms of UTIs during (n = 1144) and after (n = 953) the National Action Plan on AMR 2017-2022. Quantitative urine culture was done to isolate significant bacteria causing UTI, which were then identified to the species level and tested for antimicrobial susceptibility. Tabulations, descriptive, and logistic regression analyses were used to analyze categorical and continuous variables, as well as the association between outcome and independent variables. Statistical significance was defined as P ≤0.05 at a 95% confidence interval (CI). ResultsThe overall prevalence of culture-positive UTIs was 22.8% (479 of 2097; 95% CI: 21.1-24.7%), with no significant difference between the study periods (21.8% [249 of 1144; 95% CI: 19.5-24.3%]) vs 24.1% (230 of 953; 95% CI: 21.5-26.9%), P = 0.274). We observed a significant increase in resistance to ciprofloxacin (32.0% vs 45.8%, P = 0.0481) and third-generation cephalosporins (marked by extended-spectrum β-lactamase–producing Enterobacterales [ESBL-PE], 38.7% vs 56.9%, P = 0.0307). Additionally, UTIs caused by ESBL-PE is significantly common among patients in higher-tier hospitals (58.4% vs 34.0%; OR [95% CI]: 2.51 [1.41-4.48], P = 0.002). ConclusionsThere was a significant increase in bacterial resistance to ciprofloxacin and third-generation cephalosporins, as well as ESBL-PE. These results emphasize the critical need to enhance AMR surveillance, improve infection prevention and control measures, and strengthen antimicrobial stewardship programs.

Repetitive combined doses of bacteriophages and gentamicin protect against Staphylococcus aureus implant-related infections in Galleria mellonella.

Bacteriophages infect, replicate inside bacteria, and are released from the host through lysis. Here, we evaluate the effects of repetitive doses of the Staphylococcus aureus phage 191219 and gentamicin against haematogenous and early-stage biofilm implant-related infections in Galleria mellonella. For the haematogenous infection, G. mellonella larvae were implanted with a Kirschner wire (K-wire), infected with S. aureus, and subsequently phages and/or gentamicin were administered. For the early-stage biofilm implant infection, the K-wires were pre-incubated with S. aureus suspension before implantation. After 24 hours, the larvae received phages and/or gentamicin. In both models, the larvae also received daily doses of phages and/or gentamicin for up to five days. The effect was determined by survival analysis for five days and quantitative culture of bacteria after two days of repetitive doses. In the haematogenous infection, a single combined dose of phages and gentamicin, and repetitive injections with gentamicin or in combination with phages, resulted in significantly improved survival rates. In the early-stage biofilm infection, only repetitive combined administration of phages and gentamicin led to a significantly increased survival. Additionally, a significant reduction in number of bacteria was observed in the larvae after receiving repetitive doses of phages and/or gentamicin in both infection models. Based on our results, a single dose of the combination of phages and gentamicin is sufficient to prevent a haematogenous S. aureus implant-related infection, whereas gentamicin needs to be administered daily for the same effect. To treat early-stage S. aureus implant-related infection, repetitive doses of the combination of phages and gentamicin are required.

Predictors of treatment failure following early antibiotic discontinuation in culture-negative, ventilator-associated pneumonia: an observational study.

Early antibiotic discontinuation in clinically suspected ventilator-associated pneumonia (VAP) may lead to infection relapse/recurrence and increase mortality. This study aimed to evaluate the incidence and potential predictors of treatment failure with this approach. A retrospective observational study was conducted between September 2014 and November 2016 in a mixed intensive care unit. We included clinically suspected VAP patients whose quantitative sputum cultures from endotracheal aspirate were negative, allowing antibiotic discontinuation within 24 hours. Patients were monitored for signs and symptoms of recurrent VAP. Incidence and risk factors for treatment failure, defined as pneumonia recurrence, were determined using univariate logistic regression analysis and receiver operating characteristic (ROC) curves. Forty-three patients met the inclusion criteria. The incidence of treatment failure among culture-negative VAP following early antibiotic discontinuation was 27.9% (12 patients). There were no significant differences in procalcitonin levels, leukocyte counts or body temperature between the two groups, except for the modified clinical pulmonary infection score (mCPIS) (5.42 ± 2.19 versus 3.9 ± 1.54, p = 0.014). Procalcitonin levels at VAP diagnosis and antibiotic cessation both showed low predictive capacity for treatment failure (AUC 0.56, CI 95% 0.36-0.76 and AUC 0.57, CI 95% 0.37-0.76, respectively). However, combining mCPIS with procalcitonin improved the predictive value for treatment failure (AUC 0.765, CI 95% 0.56-0.96). Early antibiotic discontinuation may lead to a high incidence of treatment failure among culture-negative VAP patients. Procalcitonin alone should not guide antibiotic discontinuation decisions while combining mCPIS and procalcitonin enhances predictive accuracy for treatment failure.

Antibiotic Efficacy against Methicillin-Susceptible Staphylococcus aureus Biofilms on Synthetic and Biological Vascular Grafts

Biofilm formation is one of the greatest challenges encountered in vascular graft infections. Our aim is to compare the efficacy of 5 antibiotics against methicillin-susceptible Staphylococcus aureus (MSSA) biofilms on the surface of 4 vascular grafts. Invitro study of 2 clinical MSSA strains (MSSA2 and MSSA6) and 4 vascular grafts (Dacron, Dacron-silver-triclosan (DST), Omniflow-II, and bovine pericardium). After a 24-hr incubation period, the graft samples were divided into 6 groups: growth control (no treatment), ciprofloxacin 4.5mg/L, cloxacillin 100mg/L, dalbavancin 300mg/L, daptomycin 140mg/L, and linezolid 20mg/L. Quantitative cultures were obtained and results expressed as log10colony-forming units per milliliter (CFU/mL). Analysis of variance was performed to compare biofilm formation between the different groups. The mean±standard deviation MSSA2 count on the growth control Dacron graft was 10.05±0.31CFU/mL. Antibiotic treatment achieved a mean reduction of 45%; ciprofloxacin was the most effective antibiotic (64%). Baseline MSSA2 counts were very low on the DST (0.50±1.03CFU/mL) and Omniflow-II (0.33±0.78CFU/mL) grafts. On the bovine pericardium patch, the count was 9.87±0.50CFU/mL, but this was reduced by a mean of 45% after antibiotic treatment (61% for ciprofloxacin). The mean MSSA6 count on the growth control Dacron graft was 9.63±0.53CFU/mL. Antibiotics achieved a mean reduction of 48%, with ciprofloxacin performing best (67% reduction). The baseline MSSA6 count on the DST graft was 8.54±0.73CFU/mL. Antibiotics reduced biofilm formation by 72%; cloxacillin was the most effective treatment (86%). The MSSA6 count on the untreated Omniflow-II graft was 1.17±1.52CFU/mL. For the bovine pericardium patch, it was 8.98±0.67CFU/mL. The mean reduction after antibiotic treatment was 46%, with cloxacillin achieving the greatest reduction (68%). In this invitro study, ciprofloxacin and cloxacillin performed best at reducing biofilms formed by clinical MSSA strains on the surface of biological and synthetic vascular grafts.

The impact of Boric Acid tubes on quantitative urinary bacterial cultures in hospitalized patients

IntroductionThe accuracy of urine culture results can be affected by pre-analytical factors such as transport delays and storage conditions. The objectives of this study were to analyze urine collection practices and assess the impact of introducing boric acid tubes for urine collection on quantitative urinary bacterial cultures of hospitalized patients in medical wards.MethodsA quasi-experimental pre-post study conducted in an acute care facility. In the pre-intervention phase (2020–2021), urine samples were transported without preservatives at room temperature. In 2022 (post-intervention), we transitioned to boric acid transport tubes, evaluating its effect on significant bacterial growth (≥ 105 CFU/ml). Bivariate and multivariate analyses identified predictors of culture positivity.ResultsThroughout the duration of the study, a total of 12,660 urine cultures were analyzed. Date and time documentation was complete for 38.3% of specimens. Culture positivity was higher with longer processing times: positivity was 21.3% (220/1034) when specimens were processed within 4 h, 28.4% (955/3364) when processed in 4–24 h, and 32.9% (137/417) when processed after 24 h (p < 0.0001). For 4-24-hour processing, positivity decreased from 30.4% (704/2317) pre-intervention to 24.0% (251/1047) post-intervention (p < 0.001), with no significant changes in < 4 or ≥ 24-hour specimens. Stratified analysis by processing time revealed that the intervention was associated with reduced positivity only in cultures processed within 4–24 h (OR 0.80, 95% CI 0.67–0.94; p = 0.008).ConclusionThe introduction of boric acid transport tubes predominantly influenced cultures transported within a 4–24-hour window. This presents an opportunity to improve urine tract infection diagnostic practices in healthcare settings.

A Bibliometric Analysis of the Role and Research Trending of Bronchoalveolar Lavage in the Diagnosis and Treatment of Ventilator-Associated Pneumonia.

Ventilator-associated pneumonia (VAP) is one of the most common complications in intensive care units (ICUs) and negatively affects patient outcomes. Despite its widespread use as a diagnostic and therapeutic measure, the application and effectiveness of bronchoalveolar lavage (BAL) in the management of VAP require further exploration. This study aimed to evaluate the research dynamics, major trends, and scientific networks of BAL in the diagnosis and treatment of VAP using bibliometric analysis. Literature from the Web of Science database on BAL for the diagnosis and treatment of VAP from 1990 to 2024 was screened and analyzed. Keyword co-occurrence, trend analysis, and citation burst analyses were conducted using CiteSpace to identify research hotspots, core authors, institutions, and countries, as well as the evolution of research domains. The bibliometric analysis included 968 publications. Trend analysis indicated growing interest in BAL techniques, particularly in the categories of RESPIRATORY SYSTEM (burst score: 27.82) and MEDICINE, RESEARCH, and EXPERIMENTAL (burst score: 7.41). The co-citation analysis highlighted influential authors in the field, such as Torres(burst score: 9.35), Croce (burst score: 5.86), and Meduri(burst score: 5.71). Keyword analysis results revealed core clusters in the treatment of VAP with BAL, including "nonbronchoscopic lavage" (silhouette value: 0.703), "ICU-acquired infection" (silhouette value: 0.7), and "ventilator-associated tracheobronchitis" (silhouette value: 0.637). Additionally, geographic analysis showed that North America and Europe dominated the research in this field. Recently, research trends regarding protected specimen brushes and quantitative culture techniques have emerged. This study found broad applications of BAL in VAP management, especially in improving diagnostic accuracy and treatment outcomes. Optimized strategies such as improvement of lavage techniques and multidisciplinary collaboration may emerge as potential research hotspots in the future.

Efficacy of Novel Antimicrobial Therapies for Treating Staphylococcus Infections in Wistar Rats

The novel semisynthetic lipoglycopeptide dalbavancin has enhanced antibacterial action against a wide range of gram-positive bacteria. This study was conducted to evaluate the efficacy of dalbavancin in treating Staphylococcus Infections in Wistar Rats. Anaesthetized wistar rats had a Kirschner-wire and a clinical MRSA isolate placed into their proximal tibia. Twenty animals were given dalbavancin (20 mg/kg loading dose) throughout the course of four weeks after infection, or they were left untreated. Microbiological analysis was performed on tibial bones and Kirschner-wires twenty-four hours after the last treatment dosage. As opposed to control group, dalbavancin treated group showed improvement in quantitative bacterial cultures of osseous tissue. After four weeks of treatment with dalbavancin, there was no sign of an induced glycopeptide-/lipoglycopeptide-resistant strain. In conclusion, in a rat study, dalbavancin effectively treated experimental implant-related MRSA osteomyelitis. The therapeutic effectiveness of dalbavancin in treating S. aureus infections needs more investigation; ideally, it should be studied in conjunction with biofilm active medicines.

Spectrum of Lower Respiratory Bacterial Pathogens and their Antimicrobial Susceptibility in a Tertiary Care Hospital at Rawalpindi

Objective: To study the spectrum of bacterial etiological agents causing lower respiratory tract infections and their antimicrobial susceptibility pattern in a tertiary care hospital at Rawalpindi. Methodology: A descriptive, cross-sectional study was conducted in the department of Microbiology, Armed Forces Institute of Pathology (AFIP), Rawalpindi from June to December 2021. Total 130 patients with lower respiratory tract infections (LRTIs) irrespective of age and gender were included in the study while patients of pulmonary tuberculosis, fungal diseases and patients having prior antibiotic therapy before sample collection were excluded. Non quantitative cultures were performed for sputum, non- directed bronchial lavage (NBL), pleural fluid and quantitative cultures for bronchoalveolar lavage (BAL) and endobronchial (EB) washings specimens. Antibiotic susceptibility was performed using Clinical and Laboratory Standards Institute (CLSI) 2021 guidelines. Results: Pseudomonas aeruginosa (26.9%) was found to be the most prevalent bacterial pathogen followed by Klebsiella pneumoniae (23%). Both Gram negative and Gram-positive bacteria showed highest antimicrobial resistance to flouroquinolones. Gram negative bacteria were more susceptible to aminoglycosides and carbapenems. Gram positive bacteria were most susceptible to linezolid and vancomycin. Staphylococcus aureus was isolated from 8 samples, of which 5(62.5%) were Methicillin-resistant Staphylococcus aureus (MRSA). Conclusion: This study concluded that the most frequent bacterial pathogen causing lower respiratory tract infections was Pseudomonas aeruginosa and both Gram negative and Gram-positive bacteria showed highest antimicrobial resistance to flouroquinolones.

Insertion site and risk of peripheral intravenous catheter colonization and/or local infection: a post hoc analysis of the CLEAN 3 study including more than 800 catheters

AimAlthough uncommon, infections associated with peripheral intravenous catheters (PIVCs) may be responsible for severe life-threatening complications and increase healthcare costs. Few data are available on the relationship between PIVC insertion site and risk of infectious complications.MethodsWe performed a post hoc analysis of the CLEAN 3 database, a randomized 2 × 2 factorial study comparing two skin disinfection procedures (2% chlorhexidine-alcohol or 5% povidone iodine-alcohol) and two types of medical devices (innovative or standard) in 989 adults patients requiring PIVC insertion before admission to a medical ward. Insertion sites were grouped into five areas: hand, wrist, forearm, cubital fossa and upper arm. We evaluated the risk of risk of PIVC colonization (i.e., tip culture eluate in broth showing at least one microorganism in a concentration of at least 1000 Colony Forming Units per mL) and/or local infection (i.e., organisms growing from purulent discharge at PIVC insertion site with no evidence of associated bloodstream infection), and the risk of positive PIVC tip culture (i.e., PIVC-tip culture eluate in broth showing at least one microorganism regardless of its amount) using multivariate Cox models.ResultsEight hundred twenty three PIVCs with known insertion site and sent to the laboratory for quantitative culture were included. After adjustment for confounding factors, PIVC insertion at the cubital fossa or wrist was associated with increased risk of PIVC colonization and/or local infection (HR [95% CI], 1.64 [0.92—2.93] and 2.11 [1.08—4.13]) and of positive PIVC tip culture (HR [95% CI], 1.49 [1.02—2.18] and 1.59 [0.98—2.59]).ConclusionPIVC insertion at the wrist or cubital fossa should be avoided whenever possible to reduce the risk of catheter colonization and/or local infection and of positive PIVC tip culture.

Viral load in hospitalized infants with respiratory syncytial virus bronchiolitis: a three-way comparative analysis.

Viral load measurement ofRespiratory syncytial virus (RSV) in acute bronchiolitis depends on specimen collection, viral load quantification, and transport media.The aim of this study wasto investigate viral load in three-way-comparative analyses; nasal swab versus nasal wash, quantitative real-time polymerase chain reaction (RT-PCR) versus cell tissue culture, and various transport media.A prospective cohort study of infants aged < 12 months, admitted to the Soroka Medical Center, due to acute bronchiolitis, was conducted. Two nasal swabs and two nasal wash samples (in UTM and VCM) were collected from each infant upon admission and after 48h. Samples were immediately stored at -80 °C and tested at Viroclinics DDL (Rotterdam, Netherlands). Quantitative RT-PCR and quantitative virus culture were performed using tissue culture infective dose (TCID50). Spearman's correlation coefficient test assessed the correlation between the different methods, viral load, and clinical severity score. One hundred samples were collected from 13 infants (mean age 5.7 ± 3.8 months, 46% males). Twelve patients were RSV-A positive, and one was RSV-B positive. A high correlation was found between transport media- UTM and VCM (0.92, P < 0.001) and between nasal swabs and nasal wash samples (0.62, P = 0.02). RSV signals were higher in nasal wash than in swabs. PCR signals were lower in the second collection compared to the first. No correlation was found between viral load and clinical severity. Conclusion: RSV viral load is comparable across nasal wash, nasal swabs, and various transport media. However, it did not correlate with clinical severity, probably due to the limited sample size. Broader analyses are warranted. What is Known: • Viral load measurement in Respiratory Syncytial Virus (RSV) bronchiolitis depends on specimen collection, viral load quantification, and transport media. • The COVID-19 pandemic underscored the paramount significance of proper specimen collection, notably through nasal swabs. What is New: • RSV viral load was investigated in three-way-comparative analyses. • RSV viral load correlated well across PCR and tissue culture, nasal wash and swabs, and various transport media.RSV viral load did not correlate with clinical severity.

Quantitative stool culture in hospitalized neonates: Microbiological analysis, antibiotic resistance patterns, and clinical management implications

Quantitative stool culture in hospitalized neonates: Microbiological analysis, antibiotic resistance patterns, and clinical management implications