Non-fermenting Gram-negative Bacilli Research Articles

Association of antibiotic duration and all-cause mortality in a prospective study of patients with ventilator-associated pneumonia in a tertiary-level critical care unit in Southern India

ObjectivesTo estimate all-cause mortality in ventilator-associated pneumonia (VAP) and determine whether antibiotic duration beyond 8 days is associated with reduction in all-cause mortality in patients admitted with VAP in the...

Uncommon pathogen misidentification of Herbaspirillum huttiense as Burkholderia cepacia in bacteremia: a case report.

Herbaspirillum huttiense is an opportunistic pathogen associated with rare cases of bacteremia. In this case report, H huttiense was isolated from blood samples collected from an intravenous catheter (incubated for 20.8 hours) and a peripheral vein (incubated for 14.16 hours) of a lung adenocarcinoma patient. Positive blood culture bottles were subjected to smear preparation, and Gram staining and microscopic examination revealed the presence of gram-negative rods in both aerobic bottles. We used the VITEK MS automatic microbial mass spectrometry system, VITEK 2 Compact automatic microbial analysis system, and high-throughput nucleic acid sequencing for accurate identification of the isolate. It is noteworthy that although the VITEK 2 Compact identified the isolate as Burkholderia cepacia, confirmation through VITEK MS mass spectrometry and 16S ribosomal DNA (rDNA) sequencing identified it as H huttiense. Subsequently, antimicrobial susceptibility testing was performed using the broth microdilution method, following the guidelines for nonfermenting gram-negative bacilli provided by the Clinical and Laboratory Standards Institute. This case highlights the possibility of misidentification of H huttiense as B cepacia by VITEK 2 Compact in certain situations, emphasizing the importance of considering uncommon pathogens, such as H huttiense, in the context of bacteremia in cancer patients.

Twelve-Year Dynamics of Leading Pathogens Spectrum Causing Orthopedic Infection: A Retrospective Study

Background. The number of surgeries on the musculoskeletal system is increasing every year. Along with the increasing access to orthopedic care, the number of patients with orthopedic infection, the etiological agents of which can be from various taxonomic groups, is also increasing. Staphylococcus aureus and different types of coagulase-negative staphylococci (CoNS), including S. epidermidis and S. lugdunensis, together are the causative agents in 70% of cases.
 Aim of the study — to analyze the dynamics of the microbial spectrum isolated from patients of the septic surgery department for the period from 2011 to 2022.
 Methods. We performed a retrospective analysis of the microbial spectrum isolated from patients who were treated in the septic surgery department from January 1, 2011 to December 31, 2022. The leading pathogens were microorganisms whose share in the spectrum exceeded 3.5%. Of the isolated pathogens, 48.8% were the only etiological agents, and microbial associations were detected in 51.2% of the isolated pathogens.
 Results. A total of 10,327 bacteria strains were identified over the 12-year period. The leading microorganisms causing orthopedic infection were Staphylococcus spp., Enterococcus spp., Propionibacterium spp., Pseudomonas aeruginosa, Corynebacterium spp., Streptococcus spp., Klebsiella spp. and Acinetobacter spp. In the dynamics of isolated pathogens during the analyzed period, several trends were determined: a decrease in the shares of S. aureus, Enterococcus spp., P. aeruginosa, Acinetobacter spp. and an increase in the shares of CoNS and Corynebacterium spp.
 Conclusion. During 12 years, in the microbial spectrum of orthopedic infection in patients of the septic surgery department of our Center, Gram-positive bacteria, in the majority representatives of the genus Staphylococcus, prevailed. At the same time, a significant decrease in the share of S. aureus strains and an increase in the frequency of isolation of various species of CoNS were registered. A significant decrease in the number of non-fermenting Gram-negative bacteria was also revealed.

Healthcare-associated infections in patients with severe COVID-19 supported with extracorporeal membrane oxygenation: a nationwide cohort study

BackgroundBoth critically ill patients with coronavirus disease 2019 (COVID-19) and patients receiving extracorporeal membrane oxygenation (ECMO) support exhibit a high incidence of healthcare-associated infections (HAI). However, data on incidence, microbiology, resistance patterns, and the impact of HAI on outcomes in patients receiving ECMO for severe COVID-19 remain limited. We aimed to report HAI incidence and microbiology in patients receiving ECMO for severe COVID-19 and to evaluate the impact of ECMO-associated infections (ECMO-AI) on in-hospital mortality.MethodsFor this study, we analyzed data from 701 patients included in the ECMOSARS registry which included COVID-19 patients supported by ECMO in France.ResultsAmong 602 analyzed patients for whom HAI and hospital mortality data were available, 214 (36%) had ECMO-AI, resulting in an incidence rate of 27 ECMO-AI per 1000 ECMO days at risk. Of these, 154 patients had bloodstream infection (BSI) and 117 patients had ventilator-associated pneumonia (VAP). The responsible microorganisms were Enterobacteriaceae (34% for BSI and 48% for VAP), Enterococcus species (25% and 6%, respectively) and non-fermenting Gram-negative bacilli (13% and 20%, respectively). Fungal infections were also observed (10% for BSI and 3% for VAP), as were multidrug-resistant organisms (21% and 15%, respectively). Using a Cox multistate model, ECMO-AI were not found associated with hospital death (HR = 1.00 95% CI [0.79–1.26], p = 0.986).ConclusionsIn a nationwide cohort of COVID-19 patients receiving ECMO support, we observed a high incidence of ECMO-AI. ECMO-AI were not found associated with hospital death.Trial registration number NCT04397588 (May 21, 2020).

Reduce susceptibility to cefiderocol in gram negative bacteria in children: Is hope already lost before it’s even arrived?

BackgroundIn last years the diffusion of carbapenem resistance in Gram-negative bacteria (CR-GNB) is increasing worldwide, mainly due to the expression of carbapenemases. Cefiderocol has molecular characteristics that ideally confers activity against all CR-GNB, but resistant strains have already been identified. We describe cefiderocol susceptibility profile among multi-drug resistant Gram-negative isolated from pediatric patients. MethodsProspective, single pediatric center study, 1st January 2020–15th June 2023. All GNB carbapenemases producers or phenotypically carbapenem-resistant isolated in the study period were tested for cefiderocol susceptibility. Clinical and microbiological data were collected. A descriptive analysis was performed, comparing the groups of cefiderocol-resistant vs. cefiderocol-susceptible Enterobacterales and non-fermenting Gram-negative bacteria (NF-GNB). ResultsForty-seven GNB were tested for cefiderocol susceptibility; 38% were cefiderocol-resistant: 16/30 (52%) among Enterobacterales and 2/17 (12%) among NF-GNB. None of the patients were previously exposed to cefiderocol. Looking at Enterobacterales, resistance to ceftazidime/avibactam was higher among cefiderocol-resistant vs. cefiderocol-susceptible strains (62% vs 36%, respectively), as MBL expression (67% vs. 36%, respectively). Too few NF-GNB were cefiderocol-resistance to draw any conclusion. No difference in ICU admission and mortality was identified comparing cefiderocol-resistant vs. susceptible strains. Patients colonized/infected by cefiderocol-resistant strains had been previously hospitalized more frequently. ConclusionIn our cohort cefiderocol resistance was mostly registered among Enterobacterales, and especially among MBL producers’ strains (that were alongside resistant to ceftazidime/avibactam). This could be explained by the known possible cross resistance mechanism among ceftazidime/avibactam and cefiderocol. Also, correlation of cefiderocol-resistance with previous hospitalization could be associated with horizontal resistance transmission. Looking at our data, we believe that cefiderocol should be use cautiously, especially empirically and in monotherapy, due to the high resistance rate.

The Role of Matrix-Assisted Laser Desorption Ionization-Time of Flight- Mass Spectrometry (MALDI-TOF-MS) in the Identification of Non-fermenting Gram-Negative Bacilli from Clinical Isolates in a Tertiary Care Hospital

Non-fermenting Gram-negative bacilli (NFGNB) are a heterogeneous group of aerobic non-spore forming bacilli. Matrix-Assisted Laser Desorption Ionization-Time of Flight- Mass Spectrometry (MALDI-TOF-MS) is a quick, precise diagnostic method that could identify the isolates at the species level. The aim of the study is to identify the non-fermenters isolated from various clinical infections by MALDI-TOF analysis and to detect the antibiogram of these isolates. The non-fermenters were isolated from various clinical specimens, plated on Blood agar and MacConkey agar and incubated at 37⁰C for 24 hours. Identification was done on the basis of colony morphology, Gram stain, and MALDI-TOF Analysis. Antimicrobial Susceptibility Testing was done by Kirby- Bauer Disc Diffusion Technique using commercially available antibiotics on Muller-Hinton Agar. A total of 360 samples were studied. The majority of the non-fermenters were from Blood/ Body fluids (39.72%). Acinetobacter spp (31.67%) was the most common isolate, followed by Pseudomonas spp (22.50%). Other non-fermenters like Stenotrophomonas maltophilia, Burkholderia spp, Elizabethkingia spp, Achromobacter spp, Chryseobacterium spp, Ralstonia spp, Pandoraea spp, Rhizobium radiobacter, Sphingomonas spp, Ochrobactrum spp, Myroides odoratimimus and Brevundimonas spp were rarely isolated non-fermenters. Most of the strains were multi drug resistant to commonly used antibiotics like Cephalosporins, Aminoglycosides and Carbapenems. Our results showed that identifying non-fermenters using MALDI-TOF MS is a reliable and rapid technique that shortens the time to initiate appropriate therapy and even the length of the hospital stay.

Central venous catheter-related bloodstream infections: Epidemiology and risk factors for hematogenous complications

BackgroundCentral catheter-related bloodstream infections (CRBIs) can lead to severe complications, including suppurative thrombophlebitis, endocarditis, and metastatic infections. While complications due to CRBIs caused by Staphylococcus aureus (SA) are well-known, there are limited data regarding CRBIs caused by other bacteria. MethodsThis 2-year retrospective single-center study of patients with CRBIs from a tertiary care hospital examined the hematogenous complications associated with CRBIs according to patient characteristics, central venous catheter (CVC) types, and causative bacteria. ResultsAll in all, 254 patients with confirmed CRBIs were included; 285 bacteria types were isolated, mainly Enterobacteriaceae (n = 94), coagulase-negative Staphylococci (CNS, n = 82), SA (n = 45), and non-fermenting Gram-negative bacteria (NGB, n = 45). Among the patients, 35 developed at least one hematogenous complication (14 %), including suppurative thrombophlebitis (n = 15), endocarditis (n = 7) and metastatic infections (n = 16). In multivariate analysis, hemodialysis, persistent bacteremia for at least 3 days, and CRBIs caused by SA were associated with increased risk for hematogenous complications, while previous curative anticoagulant treatment was associated with reduced risk. Diabetes, CVC maintenance, and hematogenous complications were associated with increased 3-month mortality. ConclusionA thorough investigation of hematogenous complications should be envisioned in patients with persistent bacteremia, particularly those with SA infections and those on hemodialysis.

Preliminary reading of antibiogram by microdilution for clinical isolates in urine culture.

We evaluated a modification of automated antibiograms in urine cultures designed to facilitate the early interpretation of minimum inhibitory concentrations (MICs) and accelerate the targeted treatment of urinary tract infections (UTIs), METHODS: A prospective study was conducted of 309 isolates (219 Enterobacteriaceae, 75 Enterococcus spp., and 15 non-fermenting Gram-negative bacilli (NFGNB), and a retrospective study of 9 carbapenemase-producing clinical isolates from urine cultures. Colonies grown on conventional isolation plates were inoculated in MicroScan Walkaway system panels and incubated for 7 h, using a MicroScan AutoScan-4 plate reader for preliminary MIC determination by turbidimetry. Resulting antibiograms were compared with definitive antibiograms obtained after incubation for 17 h. Preliminary and definitive readings were concordant for 86.7% of Gram-positive cocci isolates (65/75), 61.6% of Enterobacteriaceae (135/219), and 53.3% of NFGNB. The agreementrate was greater than 90% for most antimicrobials against Gram-positive cocci (94.7% or more) and Enterobacteriaceae, (97.2% or more for 10 of 17 antibiotics) except with nitrofurantoin (89%). The agreement rate was 86.7% or more for most antibiotics against NFGNB apart from piperacillin/tazobactam, aztreonam, amikacin, and ciprofloxacin. Gram-negative bacilli showed the highest differences in MIC values between preliminary and definitive readings. A preliminary antibiogram reading may be useful in urine cultures to reduce the delay before targeted antibiotherapy, especially against Enterobacteriaceae and Gram-positive cocci, but not in cases of carbapenemase-producing NFGNB. Further local studies are warranted to evaluate the usefulness of this approach in relation to resistance rates.

Single-drug versus combination antimicrobial therapy in critically ill patients with hospital-acquired pneumonia and ventilator-associated pneumonia due to Gram-negative pathogens: a multicenter retrospective cohort study

Key messagesIn this study including 391 critically ill patients with nosocomial pneumonia due to Gram-negative pathogens, combination therapy was not associated with a reduced hazard of death at Day 28 or a greater likelihood of clinical cure at Day 14. No over-risk of AKI was observed in patients receiving combination therapy.BackgroundThe benefits and harms of combination antimicrobial therapy remain controversial in critically ill patients with hospital-acquired pneumonia (HAP), ventilated HAP (vHAP) or ventilator-associated pneumonia (VAP) involving Gram-negative bacteria.MethodsWe included all patients in the prospective multicenter OutcomeRea database with a first HAP, vHAP or VAP due to a single Gram-negative bacterium and treated with initial adequate single-drug or combination therapy. The primary endpoint was Day-28 all-cause mortality. Secondary endpoints were clinical cure rate at Day 14 and a composite outcome of death or treatment-emergent acute kidney injury (AKI) at Day 7. The average effects of combination therapy on the study endpoints were investigated through inverse probability of treatment-weighted regression and multivariable regression models. Subgroups analyses were performed according to the resistance phenotype of the causative pathogens (multidrug-resistant or not), the pivotal (carbapenems or others) and companion (aminoglycosides/polymyxins or others) drug classes, the duration of combination therapy (< 3 or ≥ 3 days), the SOFA score value at pneumonia onset (< 7 or ≥ 7 points), and in patients with pneumonia due to non-fermenting Gram-negative bacteria, pneumonia-related bloodstream infection, or septic shock.ResultsAmong the 391 included patients, 151 (38.6%) received single-drug therapy and 240 (61.4%) received combination therapy. VAP (overall, 67.3%), vHAP (16.4%) and HAP (16.4%) were equally distributed in the two groups. All-cause mortality rates at Day 28 (overall, 31.2%), clinical cure rate at Day 14 (43.7%) and the rate of death or AKI at Day 7 (41.2%) did not significantly differ between the groups. In inverse probability of treatment-weighted analyses, combination therapy was not independently associated with the likelihood of all-cause death at Day 28 (adjusted odd ratio [aOR], 1.14; 95% confidence interval [CI] 0.73–1.77; P = 0.56), clinical cure at Day 14 (aOR, 0.79; 95% CI 0.53–1.20; P = 0.27) or death or AKI at Day 7 (aOR, 1.07; 95% CI 0.71–1.63; P = 0.73). Multivariable regression models and subgroup analyses provided similar results.ConclusionsInitial combination therapy exerts no independent impact on Day-28 mortality, clinical cure rate at Day 14, and the hazard of death or AKI at Day 7 in critically ill patients with mono-bacterial HAP, vHAP or VAP due to Gram-negative bacteria.

Microbiological profile and antibiotic resistance of urinary tract infections in Maternity and Children Hospital, Hafr Al Batin, Saudi Arabia within 2022

Objective: This study aimed to characterize the antibiotic sensitivity, microbial resistance, and prevalence of the bacteria responsible for urinary tract infections (UTIs) at Maternity and Children Hospital (MCH), Hafr Al Batin, Saudi Arabia. Methods: Analysis was done on 1273 culture samples that were processed in the microbiology lab between January and December of 2022. Results: In all, 1273 urine culture (UC) samples were gathered. Gram-negative bacteria accounted for 46.9% of the 1273 positive UC, followed by Gram-positive bacteria with 28.8%, fungal pathogens with 13.1%, and Gram-negative non-fermenting bacteria with 11.2%. The most common uropathogenic organism (76.8%) was Pseudomonas aeruginosa, which was followed by Escherichia coli (55.6%), Staphylococcus epidermidis (22.9%), and Klebsiella pneumonia (24.3%). Candida albicans (69.5%) was determined to be the most frequent agent in terms of fungus, followed by C. glabrata (19.2%). The study revealed that the bacterial isolates exhibited effective resistance to antimicrobial drugs such as Amikacin, Cefepime, Ciprofloxacin, Gentamicin, imipenem, Levofloxacin, and Piperacillin/Tazobactam when administered against Gram-negative bacteria. Furthermore, the most effective antibiotics against Gram‑positive was Erythromycin but were sensitive to Vancomycin. Conclusions: One of the most typical infections that affect women is bacterial urinary tract infection. Using antibiotics for a very long time, and their misuse will result in the widespread growth of resistant bacteria.

The Challenges of The Diagnostic and Therapeutic Approach of Patients with Infectious Pathology in Emergency Medicine.

A retrospective observational study was performed on 657 patients, from whom clinical samples (urine, purulent secretions, blood cultures, etc.) were collected for microbiological diagnosis in the first 3 days after presentation in the ED. The identification of pathogens and the antimicrobial susceptibility testing with minimum inhibitory concentration determination were carried out according to the laboratory protocols. From the 767 biological samples analyzed, 903 microbial isolates were identified. E. coli was most frequently isolated (24.25%), followed by Klebsiella spp., S. aureus (SA), and non-fermentative Gram-negative bacilli. E. coli strains maintained their natural susceptibility to most antibiotics tested. In the case of Pseudomonas spp. and Acinetobacter spp., increased rates of AMR were identified. Also, 32.3% of SA strains were community-acquired MRSA. The introduction of rapid microbiological diagnostic methods in emergency medicine is imperative in order to timely identify AMR strains and improve therapeutic protocols.

In vitro activity of cefiderocol and comparator antibiotics against multidrug-resistant non-fermenting Gram-negative bacilli.

This study evaluated the in vitro activity of cefiderocol, ceftazidime/avibactam, and aztreonam/avibactam against clinically important multidrug-resistant non-fermenting Gram-negative bacilli. Bacteraemic isolates of 126 multidrug-resistant Acinetobacter baumannii (MDRAB), 110 imipenem-resistant Pseudamoas aeruginosa [including 14 difficult-to-treat resistant P. aeruginosa (DTRPA)], 45 beta-lactam-non-susceptible Burkholderia cepacia complex (BCC), 47 levofloxacin or trimethoprim/sulfamethoxazole-non-susceptible Stenotrophomonas maltophilia and 22 ciprofloxacin-non-susceptible Elizabethkingia spp. collected between 2019 and 2021 were subjected to MIC determination for cefiderocol, ceftazidime/avibactam and aztreonam/avibactam. The MIC50/90s of cefiderocol for drug-resistant A. baumannii, P. aeruginosa, BCC, S. maltophilia and Elizabethkingia spp. were 0.25/2, 0.25/1, ≤0.06/≤0.06, ≤0.06/0.25 and >32/>32 mg/L, respectively. Cefiderocol inhibited 94.4% (119/126) of MDRAB, 100% of imipenem-resistant P. aeruginosa, 100% of DTRPA and 100% of BCC at an MIC ≤4 mg/L, and 97.9% (46/47) of S. maltophilia at ≤1 mg/L. Ceftazidime/avibactam inhibited 76.4% (84/110) of imipenem-resistant P. aeruginosa, 21.4% (3/14) of DTRPA and 68.9% (31/45) of BCC at an MIC ≤8 mg/L. Aztreonam/avibactam had MIC50/90s of 16/>32, 8/16 and 4/8 mg/L for imipenem-resistant P. aeruginosa, BCC and S. maltophilia, respectively. At ≤8 mg/L, aztreonam/avibactam inhibited 7.1% (1/14) of DTRPA and 93.6% (44/47) of S. maltophilia isolates. Elizabethkingia spp. demonstrated high MICs for cefiderocol, ceftazidime/avibactam and aztreonam/avibactam, with all MIC50s and MIC90s > 32 mg/L. Cefiderocol may serve as an alternative treatment for multidrug-resistant A. baumannii, P. aeruginosa, BCC and S. maltophilia when other antibiotics have been ineffective or intolerable. The role of ceftazidime/avibactam and aztreonam/avibactam in the management of BCC or S. maltophilia infections warrants further investigation.

Assessing changes in the pattern of healthcare-associated infectious agents in intensive care units during a novel coronavirus infection pandemic (COVID-19)

   Introduction. The novel coronavirus infection (COVID-19) pandemic has been a major challenge to the global healthcare system, affecting more than 32 million patients worldwide. Unprecedented anti-epidemic measures carried out in hospitals allowed clinicians to hope for a decrease of hospital infection, however, the pandemic exacerbated the problem of the spread and circulation of multidrug-resistant bacteria in hospitals.   The goal of study to conduct a comparative assessment of changes in the microbial landscape and the level of antibiotic resistance of the main pathogens of lower respiratory tract infections in ICU patients who were in different epidemiological conditions during the COVID-19 pandemic in comparison with the “pre-Covid” period.   Materials and methods. A multicenter retrospective observational cohort study was conducted, which included the ICU of 4 hospitals in Yekaterinburg, which were in different epidemiological situations during the COVID-19 pandemic, as well as a comparative analysis of the length of stay of patients in the ICU, the frequency and duration of mechanical ventilation, the resuscitation mortality rate, and also the results of microbiological examination of sputum with an assessment of the structure of pathogens and the level of their antibiotic resistance.   Results. The structure of pathogens in sputum in ICU patients of the “green zone” has not fundamentally changed. In the “red zone” there was an increase in the number of documented infections of the lower respiratory tract and blood flow, while hospitals showed differences in changes in the microbial landscape. The microbiological situation in the ICU of the “red zone” was characterized by a decrease in the number of isolated strains of Enterobacterales and non-fermenting Gram-negative bacteria by the end of the pandemic, as well as a significant increase fungi in sputum. In hospitals, where there was an alternation of periods of work in the “red” and “green” zones, there was a decrease of Enterobacterales, an increase in non-fermenting Gram-negative bacteria and a fungi. Among the microflora isolated by bacteriological methods in patients with COVID-19, gram-negative bacteria and fungi predominated, mainly Klebsiella pneumonia, Acinetobacter baumanii and fungi of the Candida spp. A significant increase in the proportion of fungi in sputum was noted in ICU patients in infectious diseases hospitals during the pandemic period. An increase in the level of antibiotic resistance of the main pathogens of lower respiratory tract infections was revealed with the appearance of multi-resistant and extremely resistant strains of Klebsiella pneumoniae and Acinetobacter baumanii. Discussion. Changes in the microbial landscape may indirectly reflect the features of immune damage in patients with a new coronavirus infection COVID-19, which, combined with the severity of the disease and the characteristics of its therapy, led to an increase in complications in the form of a secondary bacterial infection. The reasons for the increase in HAI cases include: an increase in the number of patients with severe comorbidities in an artificial closed ecosystem - the “red zone”; features of the methods of treatment (glucocorticosteroids, genetically engineered biological products - IL-6 inhibitors, etc.); high frequency of unreasonable use of antibacterial drugs; increase in the duration ofuse of various invasive devices and mechanical ventilation; changing the structure and practice of staffing hospitals, increasing the number of inexperienced medical workers and volunteers; inadequate hand hygiene, use of unsuitable individual protection means with a lack of developed methods for their processing in the new conditions.   Conclusion. The results obtained indicate the importance of the work of a multidisciplinary with a microbiologist, epidemiologist, clinical pharmacologist in order to improve the quality of care for patients, especially in a difficult epidemiological situation. Surveillance over the spread of HAI pathogens should be attributed to the most progressive form of anti-epidemic activity. Microbiological monitoring and its results can serve as the basis for making managerial decisions to combat and prevent hospital infections. It is the main method for assessing the etiology, phenotype, mechanisms of resistance to antimicrobial drugs, allows you to identify epidemiological relationships between diseases, reasonably prescribe antibiotic therapy, and conduct targeted purchases of drugs (antibiotics) for the needs of this hospital.

Phenotypic characteristics of environmental Pseudomonas aeruginosa: an in vitro study on epidemiological aspects

Pseudomonas aeruginosa is one of the most commonly isolated species among non-fermenting Gram-negative bacteria, both from clinical samples and from environmental sources. The survival of the species in harsh conditions is ensured by the production of a protective biofilm; assessment of biofilm-forming capacity aids future pathogen eradication strategies. The aim of our present study was to assess the relationship between antibiotic resistance, biofilm-forming capacity and other phenotypic virulence factors in environmental P. aeruginosa isolates. One hundred and fourteen (n = 114) isolates were included in the study, which were obtained from various geographical regions and environmental origins. Antimicrobial susceptibility testing was carried out using standard protocols. Biofilm-forming capacity and pyocyanin pigment production were tested using microtiter plate-based methods. Swarming, swimming and twitching motility, and siderophore-production were assessed using agar-plate based methodologies. Resistance in environmental isolates were highest for levofloxacin/ciprofloxacin 49.12% (n = 56), ceftazidime 42.98% (n = 49) and cefepime 35.96% (n = 41), while lowest for colistin 0% (n = 0); overexpression of RND-type efflux pumps was seen in 33.33% (n = 33) of isolates. 21.93% (n = 25) met the criteria to be classified as multidrug resistant (MDR). 17.54% (n = 20) of isolates were weak/non-biofilm producers, while (25.45%, n = 29) and (57.01%, n = 65) were moderate and strong biofilm producers, respectively. No significant differences were noted in biofilm-formation (OD570 values non-MDR [mean ± SD]: 0.396 ± 0.138 vs. MDR: 0.348 ± 0.181; p &gt; 0.05) or pyocyanin pigment production (OD686 values non-MDR: 0.403 ± 0.169 vs. MDR: 0.484 ± 0.125; p &gt; 0.05) between MDR and non-MDR environmental P. aeruginosa. Highest motility values were observed for swarming motility, followed by swimming and twitching motility; no relevant differences (p &gt; 0.05) in motility were noted in the context of MDR status or biofilm-formation in the tested isolates. P. aeruginosa is an opportunistic pathogen with high medical importance, being a causative agent of recalcitrant infections, which are becoming difficult to treat with the onset of MDR. Further studies are warranted to assess biofilm-forming capacity, and to provide insights into the mechanisms underlying biofilm-formation both in isolates of clinical and environmental origins.

Outcome and Predictors of Treatment Failure in Chronic Osteomyelitis Using Bioactive Glass Granules and Putty Formulations.

The aim of this study is to evaluate the outcome of patients with cavitary chronic osteomyelitis undergoing adjuvant treatment with bioactive glass (BAG) S53P4 and identify the independent risk factors (RFs) for recurrence in 6- and 12-month patient follow-up. A retrospective, multicentre observational study conducted in tertiary specialised hospitals among patients undergoing the surgical treatment of chronic cavitary osteomyelitis using BAG-S53P4 in a granule and/or putty formulation to assess the clinical outcome and RFs for failure in 6- and 12-month patient follow-up. Of the 92 and 78 patients with 6-month and 12-month follow-ups, infection was eradicated in 85.9% and 87.2%, respectively. In the 6-month follow-up, BAG-S53P4 in the granule formulation presented a greater risk of recurrence compared to the bioactive glass putty formulation or combined granules and putty (prevalence ratio (PR) = 3.04; confidence interval 95% [CI95%]: 1.13-10.52) and neoplasia (PR = 5.26; CI95%: 1.17-15.52). In the 12-month follow-up cohort of 78 patients, smoking (PR = 4.0; 95% CI: 1.03-15.52) and nonfermenting GNB infection (PR = 3.87; CI95%: 1.09-13.73) presented a greater risk of recurrence. BAG-S53P4 is a viable option for bone-void filling and the treatment of chronic cavitary osteomyelitis. Formulations of BAG with putty or in combination with granules showed better results.

Luteibacter jiangsuensis blood stream infection: a first case report

BackgroundLuteibacter jiangsuensis is a gram-negative aerobic bacillus that was first isolated from soil samples at a pesticide factory in China and reported in 2011. Here, we describe the first case of L. jiangsuensis infection in human.Case presentationA 59-year-old Japanese woman undergoing treatment for Crohn’s disease was admitted to our hospital with fever. Clinical examination indicated catheter-related bloodstream infection. The catheter was removed and meropenem was initiated. Morphologically identical glucose non-fermentative gram-negative bacilli were detected from two sets of aerobic blood culture and catheter-tip cultures. MALDI-TOF mass spectrometry failed to identify the bacterium, which was later identified as L. jiangsuensis by 16 S rRNA gene sequencing. Antimicrobial susceptibility test revealed that the isolate was resistant to carbapenem, therefore meropenem was switched to intravenous levofloxacin (500 mg/day). After 14 days of treatment with levofloxacin, the patient was discharged.ConclusionsThis is the first case of L. jiangsuensis infection in human. The strain was identified by 16 S rRNA gene sequence analysis.

Evolving trends among Pseudomonas aeruginosa: a 12-year retrospective study from the United Arab Emirates.

Pseudomonas is a group of ubiquitous non-fermenting Gram-negative bacteria (NFGNB). Of the several species associated with humans, Pseudomonas aeruginosa (PA) can acclimate to diverse environments. The global frequency of PA infections is rising and is complicated by this organism's high intrinsic and acquired resistance to several clinically relevant antibiotics. Data on the epidemiology, levels, and trends of antimicrobial resistance of PA in clinical settings in the MENA/GCC region is scarce. A retrospective 12-year analysis of 56,618 non-duplicate diagnostic Pseudomonas spp. from the United Arab Emirates (UAE) was conducted. Data was generated at 317 surveillance sites by routine patient care during 2010-2021, collected by trained personnel and reported by participating surveillance sites to the UAE National antimicrobial resistance (AMR) Surveillance program. Data analysis was conducted with WHONET (https://whonet.org/). Among the total isolates (N = 56,618), the majority were PA (95.6%). Data on nationality revealed 44.1% were UAE nationals. Most isolates were from soft tissue (55.7%), followed by respiratory tract (26.7%). PA was more commonly found among inpatients than among outpatients, followed by ICUs. PA showed a horizontal trend for resistance to fluoroquinolones, 3rd- and 4th-generation cephalosporins, and decreasing trends of resistance for aminoglycosides and meropenem. The highest percentage of multidrug resistant (MDR) isolates was reported in 2011 at 35.6%. As an overall trend, the percentage of MDR, extensively drug-resistant (XDR), and possible pandrug-resistant (PDR) isolates generally declined over the study period. Carbapenem-resistant PA (CRPA) were associated with a higher mortality (RR: 2.7), increased admission to ICU (RR: 2.3), and increased length of stay (LOS) (12 excess inpatient days per case), as compared to carbapenem-susceptible PA (CSPA). The resistance trends in Pseudomonas species in the UAE indicated a decline in AMR and in percentages of Pseudomonas isolates with MDR and XDR profiles. The sustained Pseudomonas spp. circulation particularly in the hospital settings highlights the importance of surveillance techniques, infection control strategies, and stewardship to limit the continued dissemination. This data also shows that CRPA are associated with higher mortality, increased ICU admission rates, and a longer hospitalization, thus higher costs due to increased number of in-hospital and ICU days.

Non-fermenter Gram-negative bacilli at a tertiary hospital, South Africa.

Non-fermenting Gram-negative bacilli (NFGNB) are a significant cause of healthcare-associated infections and are often implicated in nosocomial outbreaks. Non- fermenting Gram-negative bacilli tend to have variable susceptibility patterns that make the choice of empiric therapy difficult and thus treatment must be based on in vitro susceptibility testing of each antimicrobial agent. To describe the epidemiology of the NFGNB isolated from adult patients at Chris Hani Baragwanath Hospital (CHBAH) and to assess their antimicrobial susceptibility patterns in order to guide empiric therapy and inform infection prevention and control practices. Organisms isolated from sterile sites of adult in-patients between 01 January 2016 to 31 December 2018 were retrospectively analysed. A total of 2005 NFGNB isolated. Blood cultures were the most common specimen type (91.4%). Acinetobacter species were the most commonly isolated organisms (65.1%), followed by Pseudomonas species (26.5%). The majority of NFGNB were isolated from patients in surgical wards (38.9%) followed by medical wards (35.2%). Most (60%) of the Acinetobacter species were extremely drug resistant. Pseudomonas species were more susceptible than the Acinetobacter species with an overall susceptibility rate of 86% for Pseudomonas species. The rates of antimicrobial resistance demonstrated among Acinetobacter and Pseudomonas species were high, which illustrates the threat of antimicrobial resistance also seen worldwide. An emergence of NFGNB with intrinsic multidrug resistance (Stenotrophomonas maltophilia and Burkholderia cepacia) was noted. We suggest empiric therapy with a carbapenem sparing regimen of piperacillin-tazobactam in combination with amikacin and that empiric therapy be reviewed annually when cumulative antibiograms are done. Understanding of the distribution and antimicrobial susceptibility patterns of NFGNB at CHBAH.

Soil-specific responses in the antibiotic resistome of culturable Acinetobacter spp. and other non-fermentative Gram-negative bacteria following experimental manure application.

Acinetobacter spp. and other non-fermenting Gram-negative bacteria (NFGNB) represent an important group of opportunistic pathogens due to their propensity for multiple, intrinsic, or acquired antimicrobial resistance (AMR). Antimicrobial resistant bacteria and their genes can spread to the environment through livestock manure. This study investigated the effects of fresh manure from dairy cows under antibiotic prophylaxis on the antibiotic resistome and AMR hosts in microcosms using pasture soil. We specifically focused on culturable Acinetobacter spp. and other NFGNB using CHROMagar Acinetobacter. We conducted two 28-days incubation experiments to simulate natural deposition of fresh manure on pasture soil and evaluated the effects on antibiotic resistance genes (ARGs) and bacterial hosts through shotgun metagenomics. We found that manure application altered the abundance and composition of ARGs and their bacterial hosts, and that the effects depended on the soil source. Manure enriched the antibiotic resistome of bacteria only in the soil where native bacteria had a low abundance of ARGs. Our study highlights the role of native soil bacteria in modulating the consequences of manure deposition on soil and confirms the potential of culturable Acinetobacter spp. and other NFGNB to accumulate AMR in pasture soil receiving fresh manure.

Multidrug-resistant among Non-Fermenting Gram-negative Bacteria Isolated in the Department of Microbiology of a Tertiary Care Centre.

Infection caused by Non-fermenting Gram-negative bacteria (NFGNB) like Pseudomonas aeruginosa and Acinetobacter baumannii leads to life-threatening conditions. These bacteria are often multidrug-resistant which leads to limited therapeutic options leading to treatment failure. Little information is available regarding the prevalence and resistance pattern of such bacteria in our country. The aim of the study was to find out the prevalence of multidrug-resistant among non-fermenting Gram-negative bacteria isolated in the Department of Microbiology of a tertiary care centre. A descriptive cross-sectional study was conducted in the Department of Microbiology of a tertiary care centre from 1 September 2021 to 30 August 2022 after obtaining ethical approval from the Institutional Review Committee. All samples received in the Microbiology laboratory for diagnostic purposes were included. A convenience sampling method was used. The point estimated was calculated at a 95% Confidence Interval. Among 412 non-fermenting Gram-negative bacteria, multidrug resistance was observed in 373 (90.53%) (87.70-93.36, 95% Confidence Interval) isolates. Among 373 isolates, Acinetobacter baumannii was 253 (67.83%) and Pseudomonas aeruginosa was 120 (32.17%). The prevalence of multidrug-resistant non-fermenting Gram-negative bacteria was found to be higher than in the study conducted in similar settings. Acinetobacter baumannii; antibiotic; Pseudomonas aeruginosa; prevalence.