Antimicrobial Susceptibility Testing Results Research Articles

Using the CLSI rAST breakpoints of Enterobacterales in positive blood cultures

ObjectivesThe objective of this study was to provide the clinic with rapid and accurate results of antimicrobial susceptibility testing for the treatment of patients with bloodstream infections. To achieve this, we applied the Clinical and Laboratory Standards Institute (CLSI) blood culture direct rapid antimicrobial susceptibility test (rAST) to assess the susceptibility of the most common Enterobacterales found in blood cultures. MethodsIn this study, we utilized the CLSI blood culture direct rapid antimicrobial susceptibility test to assess the susceptibility (rAST) of the most common Enterobacterales present in blood cultures. We chose this method for its simplicity in analysis, and our aim was to predict minimum inhibitory concentrations (MICs) using the rAST. As a benchmark, we assumed that Broth Macrodilution method (BMD) results were 100% accurate. For data evaluation, we employed the terms categorical agreement (CA), very major errors (VME), and major errors (ME). ResultsOur findings demonstrate that the CLSI rAST method is reliable for rapidly determining the in vitro susceptibility of Enterobacterales to common antimicrobial drugs in bloodstream infections. We achieved a concordance rate of 90% in classification within a 10-hour timeframe. We identified a total of 112 carbapenem-resistant Enterobacterales (CRE) strains, and there was no significant difference in the detection rate of CRE at 6, 10, and 16 hours. This suggests that CRE can be identified as early as 6 hours. ConclusionThe CLSI rAST is a valuable tool that can be utilized in clinical practice to quickly determine the susceptibility of Enterobacterales to antimicrobial drugs within 10 hours. This capability can greatly assist in the clinical management of patients with bloodstream infections.

Meta-analysis of antimicrobial activity of Allium, Ocimum, and Thymus spp. confirms their promising application for increasing food safety

Biopreservation strategies such as the use of Mediterranean plant extracts to ensure food safety are promising to deal with the emergence of antimicrobial resistances and the overreliance on food chemical additives. In the last few decades, antimicrobial susceptibility testing (AST) for evaluating the in vitro antibacterial potential of plant extracts against the most relevant foodborne pathogens has been widely reported in the literature. The current meta-analysis aimed to summarise and analyse the extensive evidence available in the literature regarding the in vitro antimicrobial capability of Allium, Ocimum and Thymus spp. extracts against foodborne pathogens. A systematic review was carried out to gather data on AST results of these extracts against Listeria monocytogenes, Staphylococcus aureus, Salmonella spp., Escherichia coli and Bacillus cereus, including inhibition diameters (ID) and minimum inhibitory concentrations (MIC). A total of 742 records were gathered from a raw collection of 2,065 articles. Weighted mixed-effect linear models were adjusted to data to obtain pooled ID, pooled MIC and the relationship between both model estimations and observations. The pooled results revealed B. cereus as the most susceptible bacteria to Allium sativum (pooled ID = 20.64 ± 0.61 mm) by diffusion methods and S. aureus (pooled MIC = 0.146 mg/mL) by dilution methods. Diffusion methods did not yield conclusive results for Ocimum spp. extracts; however, the lowest pooled MIC was obtained for S. aureus (0.263 mg/mL). Among the foodborne pathogens evaluated, B. cereus showed the highest sensitivity to Thymus spp. extracts by both diffusion and dilution methods (pooled ID = 28.90 ± 2.34 mm and MIC = 0.075 mg/mL). The methodology used for plant extraction was found to not significantly affect MIC values (p > 0.05). Overall, the antimicrobial effectiveness of the studied extracts against Gram-positive and Gram-negative bacteria was demonstrated. Finally, the robustness of the meta-regression model was confirmed, also revealing an inversely proportional correlation between the ID and MIC measurements (p < 0.0001). These results provide a robust scientific basis on the factors affecting the in vitro antimicrobial efficacy of extracts from Mediterranean plants. They also provide valuable information for stakeholders involved in their industrial application in food, including producers, regulatory agencies and consumers which demand green-labelled foods.

Diagnostic Accuracy of Blind Bronchial Sample Testing by BioFire Pneumonia plus Panel in Pediatric Intensive Care Unit Patients and Its Impact in Early Adaptation of Antimicrobial Therapy: A Prospective Observational Study.

Community-acquired and nosocomial lower-respiratory-tract infections in critically ill pediatric patients require early appropriate antibiotic therapy to optimize outcomes. Using blind bronchial samples, we assessed the diagnostic performance of the rapid-multiplex polymerase chain reaction (PCR) assay BioFire Pneumonia plus Panel vs. reference standard culturing with antimicrobial susceptibility testing. For this prospective observational study in a single pediatric intensive care unit, we included consecutive patients younger than 18 years admitted for suspected community-, hospital- or ventilator-associated pneumonia in 2021-2022. Sensitivity, specificity, positive predictive value and negative predictive value of the multiplex PCR assay were determined. The kappa coefficient was computed to assess agreement, and univariate analyses were done to identify factors associated with discrepancies between the 2 diagnostic methods. Of the 36 included patients (median age, 1.4 years; interquartile range, 0.2-9.2), 41.7%, 27.8%, and 30.5% had community-, hospital- and ventilator-associated pneumonia, respectively. The overall κ was 0.74, indicating good agreement. Overall, the sensitivity of the multiplex PCR assay was 92% (95% CI: 77%-98%) and specificity 95% (95% CI: 92%-97%), with variations across microorganisms. The median time from sample collection to antimicrobial susceptibility test results was 3.9 (2.5-15) hours with the multiplex PCR assay and 60.5 (47.6-72.2) hours with the reference technique. The BioFire Pneumonia plus Panel used to test blind bronchial samples had satisfactory diagnostic performance in critically ill pediatric patients. The rapid results provided by this test may improve the appropriateness of antimicrobial therapy and help minimize the use of antibiotics.

469 Diverse Role of blaCTX-M and Porins in Mediating Ertapenem Resistance Among Carbapenem Resistant Enterobacterales

OBJECTIVES/GOALS: In this study, we aim to report the role of porins and blaCTX-M β-lactamases among Escherichia coli and Klebsiella pneumoniae, focusing on emerging carbapenem resistant Enterobacterales (CRE) subtypes, including non-carbapenemase producing Enterobacterales (NCPE) and ertapenem-resistant but meropenem-susceptible (ErMs) strains. METHODS/STUDY POPULATION: Whole genome sequencing was conducted on 76 carbapenem-resistant isolates across 5 hospitals in San Antonio, U.S. Among these, NCP isolates accounted for the majority of CRE (41/76). Identification and antimicrobial susceptibility testing (AST) results were collected from the clinical charts. Repeat speciation was determined through whole genome sequencing (WGS) analysis and repeat AST, performed with microdilution or ETEST®. Minimum inhibitory concentrations (MIC) were consistent with Clinical and Laboratory Standards Institute (CLSI M100, ED33). WGS and qPCR were used to characterize the resistome of all clinical CRE subtypes, while western blotting and liquid chromatography with tandem mass spectrometry (LC-MS-MS) were used to determine porin expression and carbapenem hydrolysis, respectively. RESULTS/ANTICIPATED RESULTS: blaCTX-Mwas found to be most prevalent among NCP isolates (p = 0.02). LC-MS/MS analysis of carbapenem hydrolysis revealed that blaCTX-M-mediated carbapenem hydrolysis, indicating the need to reappraise the term, “non-carbapenemase (NCP)®” for quantitatively uncharacterized CRE strains harboring blaCTX-M. Susceptibility results showed that 56% of all NCPE isolates had an ErMs phenotype (NCPE vs. CPE, p &lt; 0.001), with E. coli driving the phenotype (E. coli vs. K. pneumoniae, p &lt; 0.001). ErMs strains carrying blaCTX-M, had 4-fold more copies of blaCTX-M than ceftriaxone-resistant but ertapenem-susceptible isolates (3.7 v. 0.9, p &lt; 0.001). Immunoblot analysis demonstrated the absence of OmpC expression in NCP-ErMs E. coli, with 92% of strains lacking full contig coverage ofompC. DISCUSSION/SIGNIFICANCE: Overall, this work provides evidence of a collaborative effort between blaCTX-M and OmpC in NCP strains that confer resistance to ertapenem but not meropenem. Clinically, CRE subtypes are not readily appreciated, potentially leading to mismanagement of CRE infected patients. A greater focus on optimal treatments for CRE subtypes is needed.

Molecular characterization of Aeromonas hydrophila detected in Channa marulius and Sperata sarwari sampled from rivers of Punjab in Pakistan.

Aeromonas hydrophila is one of the major pathogenic bacteria responsible for causing severe outbreaks at fish farms and is also a major global public health concern. This bacterium harbors many virulence genes. The current study was designed to evaluate the antidrug and virulence potential of A. hydrophila by amplifying its antimicrobial resistance and virulence genes using PCR and examining their effects on fish tissues and organs. A total of 960 fish samples of Channa marulius and Sperata sarwari were collected from four sites of the rivers of the Punjab, Pakistan. A. hydrophila isolates were subjected to biochemical identification and detection of virulence and antimicrobial resistance (AMR) genes by PCR. We retrieved 181 (6.46%) A. hydrophila isolates from C. marulius and 177 (6.25%) isolates from S. sarwari. Amplification through PCR revealed the incidence of virulence genes in 95.7% of isolates in C. marulius and 94.4% in S. sarwari. Similarly, amplification through PCR also revealed occurrence of AMR genes in 87.1% of isolates in C. marulius and 83.9% in S. sarwari. Histopathological examination revealed congestion (5.2%) and hepatocyte necrosis (4.6%) in liver, lamellar fusion (3.3%) and the presence of bacterial colonies (3.7%) in gills, fin erosion (6%), and the presence of biofilms (3.5%) in tail fins of infected fish. Phylogenetic tree analysis of 16S rRNA and gyrB gene of A. hydrophila revealed 100% and 97% similarity, respectively, with 16S rRNA gene and gyrB of A. hydrophila isolated in previous studies. The results of antimicrobial susceptibility testing showed that all isolates demonstrated resistance to sulfamethoxazole, ampicillin, neomycin, and norfloxacin, while susceptibility to gentamicin, chloramphenicol, and tetracycline, and intermediate resistance was observed against cefotaxime. The results concluded that examined fish samples were markedly contaminated with virulent and multidrug strains of A. hydrophila which may be of a potential health risk. The study emphasizes the responsible antimicrobial use in aquaculture and the urgent need for effective strategies to control the spread of virulence and antimicrobial resistance genes in A. hydrophila.

In vitro activity of selected antimicrobials against methicillin-resistant Staphylococcus pseudintermedius of canine origin in Poland.

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an important veterinary pathogen. In general, only a few antimicrobials show in vitro activity against MRSP isolates. The objective of this study was to determine the in vitro activity of selected antimicrobials, including last-choice drugs, against clinical MRSP isolates of canine origin. The activity of 10 selected agents was evaluated against 41 clinical MRSP isolates. The disk diffusion method and minimal inhibitory concentration values were used for antimicrobial susceptibility testing (AST). The guidelines for staphylococci of canine or human origin were employed for the interpretation of the results. Among the examined MRSP isolates, resistance to enrofloxacin and clindamycin was the most prevalent (n=40; 97.6%). Resistance to doxycycline and gentamicin was observed in 83.0% (n=34) and 68.3% (n=28) of the isolates, respectively. Single isolates were resistant to chloramphenicol (n=5; 12.2%) and rifampicin (n=3; 7.3%), whereas all showed susceptibility to amikacin, vancomycin, mupirocin and linezolid. Predominantly, the results of AST obtained by both methods were consistent. Some discrepancies were observed for gentamicin; however, clinical breakpoints for staphylococci of human origin were used. Amikacin and chloramphenicol constitute potential treatment options in infections caused by MRSP and may be included in extended susceptibility testing in our geographical region. The determination of clinical breakpoints for some antimicrobials not incorporated in the recommendations should be a high priority in the veterinary diagnostics.

Antimicrobial resistance trends in clinical Escherichia coli and Klebsiella pneumoniae in Ethiopia.

Clinicians rely on local antimicrobial resistance pattern data to guide empiric treatment for seriously ill patients when culture and antimicrobial susceptibility testing results are not immediately available. This study aimed to analyse 5-year trends in antimicrobial resistance profiles of Escherichia coli and Klebsiella pneumoniae isolates. Bacteriology reports from 2017 to 2021 at the Ethiopian Public Health Institute were analysed retrospectively. Isolates were identified using either the VITEK 2 Compact system, the BD Phoenix M50 instrument, or conventional biochemical tests. Antimicrobial susceptibility testing was conducted using either the Kirby-Bauer disk diffusion method or the VITEK 2 Compact system and BD Phoenix M50 systems available at the time of testing. The Cochran Armitage trend test was employed to test the significance of antimicrobial resistance trends over time. P-values less than 0.05 were considered statistically significant. Of the 5382 bacteriology reports examined, 458 (9%) were on E. coli and 266 (5%) were on K. pneumoniae. Both K. pneumoniae (88%) and E. coli (65%) demonstrated high resistance to extended-spectrum cephalosporins. However, both K. pneumoniae (14%) and E. coli (5%) showed lower rates of resistance to carbapenems compared to other antimicrobials. In K. pneumoniae, resistance to carbapenems (from 0% to 38%; p < 0.001) and ciprofloxacin (from 41% to 90%; p < 0.001) increased significantly between 2017 and 2021. Both organisms showed very high resistance to broad-spectrum antibiotics. Additionally, K. pneumoniae demonstrated a statistically significant rise in ciprofloxacin and carbapenem resistance. This study emphasises the significance of regular reporting of local antimicrobial resistance patterns as this information can guide appropriate empiric therapy and efforts to address antimicrobial resistance issues.

The exceptions that prove the rule—a historical view of bedaquiline susceptibility

In the accompanying study, Nimmo and colleagues estimated the dates of emergence of mutations in mmpR5 (Rv0678), the most important resistance gene to the anti-tuberculosis drug bedaquiline, in over 3500 geographically diverse Mycobacterium tuberculosis genomes. This provided important insights to improve the design and analysis of clinical trials, as well as the World Health Organization catalogue of resistance mutations, the global reference for interpreting genotypic antimicrobial susceptibility testing results.

Five-year species distribution and antimicrobial susceptibility of non-tuberculous mycobacteria in Malaysia, 2018-2022.

Introduction. Non-tuberculous Mycobacteria (NTM) is a group of mycobacteria distinct from the Mycobacterium tuberculosis complex. They can cause opportunistic infections, especially in immunocompromised individuals.Gap Statement. Over the last few years, there has been a growing concern regarding the distribution and antimicrobial resistance of NTM in Malaysia. however, a comprehensive study to fully grasp the NTM situation has yet to be conducted.Aim. This study aimed to investigate the species distribution and antimicrobial susceptibility patterns of NTM isolated from clinical samples in Malaysia from 2018 to 2022.Methodology. A retrospective analysis was conducted on NTM isolates obtained from various clinical specimens over a span of five years. The isolates were identified using phenotypic and molecular techniques, and antimicrobial susceptibility profiles for clinically significant isolates were determined using minimum inhibitory concentration.Results. The study revealed a diverse distribution of NTM species in Malaysia, with Mycobacteroides abscessus complex and Mycobacterium avium complex emerging as the most predominant. Furthermore, the antimicrobial susceptibility patterns showed varying degrees of resistance to commonly used antibiotics, highlighting the significance of treatment tailored to susceptibility testing results.Conclusion. This study provides valuable perspective into the epidemiology of NTM in Malaysia. The information gained from this study should prove useful for empirically treating serious NTM infections prior to species identification and the availability of antimicrobial susceptibility testing results.

Outbreaks of bovine mastitis caused by specific Mycoplasma bovis strains recurring at multi-year intervals.

Mycoplasma bovis is a major cause of bovine mastitis. Intermittent shedding of the organism for many months is a feature of cows with intramammary infection. A dairy farm in Japan experienced a mastitis outbreak caused by M. bovis in 2016, as well as 2 additional outbreaks and 1 case in 2020-2021. The causative strains in the 3 outbreaks shared a common and identical genetic feature, the insertion of a transposase gene at the same site within the phosphate acetyltransferase-2 gene. Additionally, all isolates were genotyped to closely related sequence types (ST21 and ST141) by multilocus sequence typing, and had similar pulsopatterns by pulsed-field gel electrophoresis. Our results indicate that infection with the same causative strain remained in this herd and environment for 4 y. Treatment with fluoroquinolones, guided by antimicrobial susceptibility test results, eliminated M. bovis from 16 of 20 M. bovis-infected cows, as confirmed by culture and somatic cell counts. However, mastitis caused by other bacteria occurred in 9 M. bovis-free cows within 2 mo of the last treatment.

Disseminated Nocardia nova in a child with relapsed acute lymphoblastic leukemia: a case report

BackgroundNocardiosis is a rare infection that typically results from inhalation of or inoculation with Nocardia organisms. It may cause invasive disease in immunocompromised patients. This case describes nocardiosis with bacteremia and pulmonary involvement in a child with a hematologic malignancy.Case presentationA boy with testicular relapsed acute lymphoblastic leukemia with marrow involvement presented with sudden onset of fever, body aches, headaches, chills, and moderate respiratory distress during continuation 2 chemotherapy. Radiographic imaging demonstrated consolidation and ground glass opacities in bilateral lower lungs. Central line blood cultures grew Nocardia nova complex, prompting removal of the central line and initiation of triple therapy with imipenem-cilastatin, linezolid, and trimethoprim-sulfamethoxazole with rapid improvement of symptoms. Antibiotic susceptibilities showed a multidrug-susceptible isolate. The patient is anticipated to remain on trimethoprim-sulfamethoxazole for at least 12 months.ConclusionsIn an immunocompromised child, blood cultures, chest imaging, and head imaging can aid in the diagnosis of disseminated nocardiosis. Long-term antibiotic therapy is necessary, guided by the organism and simplified with the results of antimicrobial susceptibility testing.

Identification of Diverse Multiple Drugs Resistant Bacterial Pathogens using Microscan Panel

Bacterial isolates from clinical sources have increased resistance to antimicrobial agents available and routinely used in developing countries like Ethiopia. One of the control measures of antimicrobial resistance is to know the susceptibility of pathogenic bacteria from clinical specimens and treat patients accordingly. Therefore the objective of the present study is to isolate bacterial pathogens from different clinical specimens and determine their antimicrobial susceptibility patterns. Clinical samples (urine, blood, pus and discharges from different body sites were cultured and isolation of bacterial pathogens were done following standard bacteriological methods using media recommended by Cheesbrough. Identification of bacterial pathogens and antimicrobial susceptibility tests were done using Micro Scan Identification Panel method. The Panels were read by Micro Scan Auto Scan 4 reader after incubating for 18 to 24 hours at 35o c aerobically. The retrospective data of microbiological culture and antimicrobial susceptibility test results were analysed. A total of 995 clinical specimens were cultured at Bethzatha Bacteriology Lab., Bethzatha Hospital, from May 2021 to February 2022. The most frequent specimens were, urine 87 (32%), blood 77(28%), pus and discharges from different body sites 65(24%). Out of these, 273(27%) yielded different bacterial pathogens. The most dominant gram negative bacterial isolates from urine samples 43/87(49%), 6/87(7%), 7/87(8%) were E. coli, Acinetobacter and Klebsiella spp, respectively in that order. Klebsiella pneumoniae 12/77 (16%) were most frequently isolated from blood culture followed by diverse coagulase negative Staphylococci (CoNS) 26/77 (33.7%) and S. aureus 15/77(19.5%). The most frequent 20/65(31%) isolates from pus and discharges were S. aureus followed by 12/65(18.5%) CoNS. In the present study, most bacterial isolates from different clinical samples were multiply resistant to ampicillin, amoxicillin, trimethoprim sulphametoaxzole, levofloxacillin and ampicillin-sulbactam. On the other hand the most frequent Gram negative bacteria, E.coli and Klebsiella pneumonia were most susceptible to amikacin and ertapenem, and the gram positive isolates, S. aureus were most susceptible to levofloxacillin and gentamicin; whereas coagulase negative staphylococci (CoNS) were most susceptible to gentamicin, tecioplanin, rifampicin, vancomycin, daptomycin. Therefore clinicians should be guided by antimicrobial susceptibility test. In the absence of antimicrobial susceptibility test we suggest that the above mentioned drugs to be most appropriate for empirical treatment in the study hospitals and health settings in Addis Ababa. Furthermore critical measures need to be taken to curb the increasing spread of AMR bacteria.

Virulence genes detection and antibiotic resistant &lt;i&gt;Salmonella&lt;/i&gt; in raw and ready-to-eat snails (&lt;i&gt;Arachatina marginata&lt;/i&gt;) sold in selected markets in Port Harcourt

This study investigated the presence of virulence genes and antibiotic resistant Salmonella spp. in raw and ready-to-eat snails (Archachatina marginata) vended in selected markets within Port Harcourt, Rivers State, Nigeria. Proximate composition, isolation, identification and presence of virulent genes were done using standard methods. Raw snails from Choba had Salmonella counts ranging from 3.32 to 5.04 log10CFU/g. Salmonella was not detected in ready-to-eat samples from Choba. Raw snails from Rumuokoro had Salmonella counts ranging from 4.04 to 6.04 log10CFU/g while three of the ten ready-to-eat samples had counts ranging from 3.53 to 3.63 log10CFU/g. Raw snails from Oyigbo had Salmonella counts ranging from 4.71 to 6.67 log10CFU/g with two of the five ready-to-eat samples having Salmonella counts of 3.69 and 3.51 log10CFU/g. Antimicrobial susceptibility test results showed that all the isolates were resistant to augmentin, cefuroxi and cetazidime. Ten Salmonella representing 5% possessed the antibiotics resistance genes, fliC and invA, but not sefA. The presence of Salmonella in some of the ready-to-eat samples makes it objectionable for human consumption. But more worrisome is that some possess fliC and invA genes and resistant to common antibiotics used for their management. Therefore, proper processing and maintenance of quality of processed snail meat is very essential for public health safety.

Treatment of Mycobacterium abscessus complex pulmonary disease

Background: In South Korea, bacteria in the &lt;i&gt;Mycobacterium abscessus&lt;/i&gt; complex (MABC), a group of rapidly growing mycobacteria, are second to those in the &lt;i&gt;Mycobacterium avium&lt;/i&gt; complex as a cause of non-tuberculous mycobacterial pulmonary disease. The MABC includes several subspecies, including &lt;i&gt;M. abscessus&lt;/i&gt; subsp. &lt;i&gt;abscessus&lt;/i&gt; (&lt;i&gt;M. abscessus&lt;/i&gt;) and &lt;i&gt;M. abscessus&lt;/i&gt; subsp. &lt;i&gt;massiliense&lt;/i&gt; (&lt;i&gt;M. massiliense&lt;/i&gt;), the former of which is difficult to treat owing to its antibiotic resistance.Current Concepts: &lt;i&gt;M. abscessus&lt;/i&gt; encodes a functional erythromycin ribosomal methylase gene, &lt;i&gt;erm&lt;/i&gt;(41), that causes inducible macrolide resistance. Contrastingly, &lt;i&gt;M. massiliense&lt;/i&gt; lacks a functional &lt;i&gt;erm&lt;/i&gt;(41) gene owing to a partial deletion. Accordingly, culture conversion rates using currently recommended macrolide-based antibiotic treatments are considerably higher among patients with &lt;i&gt;M. massiliense&lt;/i&gt; infection than in those infected with &lt;i&gt;M. abscessus&lt;/i&gt;. Phase therapy (intensive and continuous) is recommended for MABC pulmonary disease and, depending on the subspecies and antimicrobial susceptibility test results, should include an initial treatment of ≥3 to 4 injectable and oral antibiotics, followed by inhaled or intravenous amikacin and ≥1 to 2 oral antibiotics. Recommended injectable antibiotics include amikacin, imipenem or cefoxitin, and tigecycline, and oral antibiotics include macrolides (azithromycin or clarithromycin), clofazimine, linezolid, and rifabutin. For some patients, surgery should be considered as an adjunctive treatment option.Discussion and Conclusion: Given that &lt;i&gt;M. abscessus&lt;/i&gt; expresses the inducible resistance gene &lt;i&gt;erm&lt;/i&gt;(41) associated with macrolide resistance, the identification of MABC subspecies is important for disease management. However, despite the combined application of several injectable/oral antibiotics, the treatment outcomes for &lt;i&gt;M. abscessus&lt;/i&gt; pulmonary disease remain unsatisfactory.

Sequencing and multiple antimicrobial resistance of Pseudomonas fluorescens isolated from Nile tilapia fish in Egypt.

Pseudomonas fluorescens is one of the main causes of septicemic diseases among freshwater fish, causing severe economic losses and decreasing farm efficiency. Thus, this research was aimed to investigate the occurrence of P. fluorescens in Nile Tilapia (O. niloticus) fish in Egypt, gene sequencing of 16SrDNA gene, and antimicrobial susceptibility. P. fluorescens strains were detected in 32% (128\400) of apparently healthy (9%; 36\400) and diseased (23%; 92\400) Nile tilapia fish. The highest prevalence was observed in gills of fish, 31.3% followed by intestine 26.9%, liver 24.2%, and kidneys 17.6%. The PCR results for the 16SrDNA gene of P. fluorescens showed 16SrDNA gene in 30% of examined isolates. Moreover, Homogeny and a strong relationship between strains of P. fluorescens was confirmed using 16SrDNA sequences. Beside the responsibility of 16SrDNA gene on the virulence of P. fluorescens. The results of antimicrobial susceptibility tests revealed that all strains were resistant to piperacillin (100%), followed by ceftazidime (29.7%), and cefepime (25.8%). The strains of P. fluorescence were highly sensitive to cefotaxime (74.2%), followed by ceftriaxone and levofloxacin (70.3% each). Interestingly, 29.7% of strains of P. fluorescens were multiple antimicrobial-resistant (MAR).

Microbiology and Antimicrobial Resistance Profile of Infectious Peritonitis: A Cohort Study with 10-year Follow-up

Abstract Objectives: Peritoneal dialysis (PD) is a feasible option for patients with renal failure, but infectious peritonitis has long been a common complication in PD. The purpose of the current study was to provide epidemiological data about the rate, microbiology profile, and antimicrobial susceptibility pattern of infectious peritonitis in adult PD patients in Saudi Arabia. Materials and Methods: A descriptive study was performed. Demographics and diagnostic data of adult PD patients between 2009 and 2019 were collected. The infectious peritonitis episodes were explained per patient and the microbiology profile along with antimicrobial susceptibility testing results were analyzed. Results: One hundred renal failure adult patients underwent PD during 2009–2019, with 55.0% were female. Ninety-three infectious peritonitis episodes were identified in 52 patients and the overall peritonitis rate was 0.56 episodes per patient-year. Gram-positive bacteria were more responsible (61.3%) for infectious peritonitis than Gram-negative bacteria (37.6%) and expressed more antimicrobial resistance patterns. Coagulase-negative Staphylococci were the most frequently isolated Gram-positive bacteria from the PD fluid culture (27.9%). Acinetobacter baumannii, followed by Pseudomonas luteola, Pseudomonas aeruginosa, and Klebsiella pneumoniae were the most common Gram-negative bacteria identified at 6.5%, 5.4%, 5.4%, and 5.4%, respectively, with susceptibility patterns detected against most of the antimicrobials tested. Conclusions: The overall rate of infectious peritonitis was 0.56 episodes per patient-year, which is higher than the reported target published by the International Society for PD. More intense training programs and establishment of a national infectious peritonitis registry are recommended to minimize infection risk and improve patients’ quality of life.

Antibiogram of Pseudomonas aeruginosa Clinical Isolates Tested for Pan, Extensive and Multidrug Resistances

Background: Pseudomonas aeruginosa usually cause nosocomial infections with concurrent morbidity and mortality and is generally resistant to many antibiotics.&#x0D; Aim: This study was aimed to determine the proportion of pan-drug-resistant (PDR), extensively drug-resistant (XDR), and multidrug-resistant (MDR) P. aeruginosa strains recovered from human samples.&#x0D; Methodology: The retrospective study was conducted in the University of Nigeria Teaching Hospital Enugu in 2023. Clinical samples obtained from patients between October 2022 and April 2023 were analysed. A total of 100 Pseudomonas aeruginosa isolates recovered from 780 clinical samples were used. Standard microbiological techniques were used to identify and categorize the isolates. Antibiotic susceptibility pattern was determined using the Kirby Bauer disc diffusion method.&#x0D; Results: Isolates recovered from wound was 38%, voided urine, catheter tip urine, ear swab, and high vaginal swab samples recorded 29%, 11%, 10% and 4%, respectively. Ceftazidime recorded the highest level of resistance (70.0%) and the least was Colistin (20%). Resistance patterns showed that 32(32.0%) bacterial strains were MDR, 68(68.0%) were XDR and no PDR was recorded.&#x0D; Conclusions: For the best selection of empirical therapy, P. aeruginosa susceptibility monitoring is essential due to the high prevalence of antibiotic resistance. The resistance pattern raises the possibility of misuse of broad-spectrum antibiotics. Treatment for bacterial infections should be directed by the results of antimicrobial susceptibility tests.

Effective Stakeholder Engagement for Collation, Analysis and Expansion of Antimicrobial Resistance (AMR) Data: A CAPTURA Experience.

An effective implementation of antimicrobial resistance (AMR) surveillance projects requires sustainable and multidisciplinary engagement with stakeholders from various backgrounds, interests and aims. The "Capturing Data on Antimicrobial resistance Patterns and Trends in Use in Regions of Asia" (CAPTURA) project, funded by the Fleming Fund, initially targeted 12 countries in South Asia (SA) and Southeast Asia (SEA) to "expand the volume of historical and current data on AMR and antimicrobial usage" and support local agencies through capacity building activities. In this article, we focus on early stakeholder engagement activities and present overall statistics on AMR data collated from 72 laboratories across seven countries. This included 2.3 million records of antimicrobial susceptibility testing (AST) data, which were curated, analyzed, and shared back to the facilities for informed decision making. Approximately 98% of the data collated by CAPTURA originated from laboratories based in SA countries. Furthermore, country-wide data were analyzed to identify commonly reported pathogens in each country, followed by descriptions of AST practices and multidrug-resistant (MDR) pathogens. Overall, we found meager adherence to standard guidelines to perform and record AST results, and a significant number of MDR pathogens were reported. We conclude that close collaboration with the existing national mechanisms for identifying AMR data sources was crucial for the project's success. Although we show a vast retrospective dataset on AMR is available for data sharing in Asia, there remain critical gaps in data generation/management practice and analysis capacity for AMR data at most facilities.

Impact of a hospital sepsis management protocol on the selection of empirical antibiotics in infectious disease consultations

It is well-established that Infectious Diseases consultation (IDC) enhances the prognosis of bloodstream infections. However, it is unclear if adoption of an institutional sepsis protocol would lead to any further improvement in a setting where IDC and infectious diseases approval (IDA) - available throughout 7 days/24 hours -are mandatory for administering broad spectrum antibiotics. We aimed to evaluate the influence of the institutional sepsis protocol developed by Department of Infectious Diseases and Clinical Microbiology on the selection of appropriate empirical antibiotics by IDC through focusing on patients who had bloodstream infections caused by Extended-spectrum β-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae, which poses a therapeutic challenge. One hundred and fifty-three adult patients (58 patients in the pre-protocol period and 95 patients in the post-protocol period), who received empirical antibiotic treatment for ESBL-producing E. coli and K. pneumoniae, in whom at least one systemic antibiotic was started either on the day blood cultures were drawn or not later than 24 hours were included in the study, retrospectively. The primary outcome was whether the empirical treatment regimen included a carbapenem that was accepted as the appropriate treatment based on the results of the MERINO trial. Secondary outcomes included empirical treatment based on pre-defined risk factors suggesting multidrug resistance (MDR), 30-day inpatient mortality, and appropriate antibacterial treatment according to antimicrobial susceptibility test (AST) results. The median age (Interquartile range) was 61 (48-70.5) years and 76 (49.7%) out of 153 patients were male. The patients in the post-protocol period were older compared to the pre-protocol period (54 years vs 64 years, p = 0.045). The Charlson Comorbidity Index was higher during the post-protocol period compared to the pre-protocol period (4 vs 5, p=0.038). At least one risk factor for MDR bacteria infection was present in 147 (96.1%) of the 153 patients. While the rate of risk factors for MDR bacteria infections did not differ significantly between the pre-protocol and post-protocol periods, the post-protocol period showed a significantly higher level of appropriate antibiotic treatment according to the presence of MDR risk factors compared to the pre-protocol period (44.8% vs 64.2%, p=0.019). There was a significant increase in the use of carbapenems in the post-protocol period compared to the pre-protocol period (34.5% vs. 56.8%, p=0.007). When the subgroup of patients who were likely to have infection caused by ESBL-producing bacteria is taken into consideration, the carbapenem use was more frequent in the post-protocol period (37.8% vs 68.9%, p=0.002). The rate of appropriate empirical treatment according to AST was not statistically different between pre-protocol and post-protocol period. The 30-day mortality rates were similar in both periods (24.1% vs 31.5, p=0.33). However, the rate of susceptibility to piperacillin-tazobactam was statistically higher in the pre-protocol period (82.6% vs 46.2%, p=0.016) when 39.7% of the patients received piperacillin-tazobactam as the empirical treatment. This study highlights the significance of using a structured protocol to attain appropriate empirical treatment for patients suspected of sepsis, even in a setting where IDC is readily available.

Evaluation of the LifeScale system for rapid phenotypic antimicrobial susceptibility testing from positive blood cultures

Abstract Objective The spread of antimicrobial resistance is a growing threat to public health, thus there is a critical need for prompt and reliable antimicrobial susceptibility testing (AST). Rapid AST may improve patient outcomes by allowing for quicker start of optimal therapy and reducing hospital length of stay, therefore decreasing overall healthcare costs. However, rapid results may not improve patient care if they are not considered equivalent to standard AST. Several platforms are under development that can provide rapid AST results; the objective of this work is to assess the performance of the new LifeScale rapid AST platform (Affinity Biosensors) that uses resonant mass measurements for calculation of antimicrobial susceptibility results. Methods Positive BACTEC blood-cultures collected from patients were included if the gram stain revealed only Gram-negative rods. Standard of care (SOC) AST results, as determined by a combination of BD Phoenix automated, Sensititre broth microdilution, and/or standard disk diffusion methods, were compared to results from direct positive blood culture testing on the LifeScale system. Minimum inhibitory concentrations (MICs) and categorical interpretations based on CLSI and/or FDA AST breakpoints were compared by microorganism and drug to calculate essential and categorical agreement for five species with pending claims on the LifeScale system: Escherichia coli (N=33), Klebsiella pneumoniae (N=10), K. oxytoca (N=5), Pseudomonas aeruginosa (N=11) and Acinetobacter sp. (N=1); tested against 13 relevant antibiotics: Amikacin, ampicillin, aztreonam, cefazolin, cefepime, ceftazidime, ceftazidime/avibactam ertapenem, gentamicin, levofloxacin, meropenem, piperacillin/tazobactam, and trimethoprim/sulfamethoxazole. Results LifeScale had 95.3% essential agreement with the SOC results, and a 93.1% categorical agreement based on CLSI M52 criteria. Of the 665 organism-drug combinations evaluated, agreement was high, with only 1 very major discrepancy, 8 major discrepancies and 37 minor discrepancies, of which 22 (47.8%) were within ±1 doubling dilution. Among these discrepancies, LifeScale MICs averaged 1 dilution higher than SOC MICs, which may reduce the risk of false-susceptible interpretations. Conclusion s: The accuracy and reliability of results from rapid AST is of utmost importance. The LifeScale technology is unique among AST platforms as it measures bacterial cell mass and counts to determine MICs for up to 14 antibiotics in ~4 h. These results suggest this platform is able to deliver rapid, actionable results to guide antimicrobial therapy for patients with bacteremia.