Semiquantitative Culture Research Articles

Fungal dysbiosis following antibacterial monotherapy in canine otitis externa.

To evaluate evidence of Malassezia overgrowth following successful topical antibacterial monotherapy of refractory canine bacterial otitis using semi-quantitative cultures. Twenty-nine dogs with bacterial otitis were treated topically with either fluoro-quinolone [0.5% enrofloxacin (18 dogs, 19 treatment events, 25 ears) or 0.1% marbofloxacin (1 ear), with 0.1% dexamethasone] ("FQ") SID, or 143 mg/mL piperacillin/18 mg/mL tazobactam ("PT") BID (11 dogs, 14 treatment events, 19 ears) for 8 to 36 days (mean 20 days). At visits 1 (V1) and 2 (V2), ear swab tips were washed in PBS + Triton X-100 and serial dilutions spread-plated onto blood, MacConkey (37°C, 48 hours) and modified Dixon's agar (32°C, 14 days) to generate semiquantitative counts. Microbes were identified by phenotype and MALDI-TOF. Prior to treatment, Pseudomonas aeruginosa was isolated alone or in combination with other bacteria in 14 FQ-treated ears and 18 PT-treated ears; the next most frequent bacteria were Streptococcus canis (8 FQ, 2 PT) and Staphylococcus pseudintermedius (8 FQ, 1 PT). The proportions of dogs' ears (excluding cross-over treatments and contra-lateral affected ears) from which bacteria were isolated were significantly reduced by treatment with both FQ (V1, 13/15; V2, 5/15) and PT (V1, 14/14; V2, 2/14). The proportions of dogs' ears from which yeasts (Malassezia pachydermatis, Candida spp.) were isolated were significantly increased by treatment in dogs treated with PT (V1, 1/14; V2, 14/14) but not FQ (V1, 3/15; V2, 6/15). Otitis cases that receive potent antibacterial monotherapy must be monitored for yeast overgrowth.

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.

Prevalence, Determinants, and Antibiotic Resistance Patterns of Urinary Tract Infections in Antenatal Women in an Urban Resettlement Colony and Slum in Delhi, India: A Cross-sectional Study

Abstract Background: Urinary tract infection (UTI) is the most common bacterial infection occurring in pregnant women with untreated, recurrent, and inadequately treated bacteriuria accentuating the risk of multiple adverse fetal and maternal health outcomes. The study objective was to determine the proportion of UTIs and their predictors along with antibiotic resistance patterns of causative organisms in pregnant women. Materials and Methods: This cross-sectional study was conducted among 348 pregnant women in an urban resettlement and slum colony. Urine samples were examined through semi-quantitative culture on plated Mac Conkey and blood agar. Antibiotic susceptibility testing was done on Muller Hinton agar using the modified Stokes’ disc diffusion method. Results: At least one symptom related to UTI was reported by 35.7% (95% CI: 30.7-41.1) of the participants. The proportion of pregnant women detected having UTI on urine culture was 7.4% (n = 24, 95% CI: 5.1-10.8) with 13 (54.2%) asymptomatic and 11 (45.8%) symptomatic cases. Overcrowding was a significant predictor of UTI. The most common organisms detected were Escherichia coli (n = 12), Klebsiella pneumoniae (n = 7), Staphylococcus aureus (n = 3), and Acinetobacter species (n = 2). Conclusions: The use of individual toilets and active screening for UTI through culture and sensitivity testing in pregnant women should be promoted in low-resource settings irrespective of symptoms. The initiation of presumptive antibiotic therapy for UTI cases in pregnant women should be restricted to painful micturition due to high false positivity of other symptoms with Nitrofurantoin being a likely preferred drug for empirical administration due to its low resistance pattern among isolated organisms.

Pediatric Urinary Tract Infections at a Tertiary Care Center: Microbial Diversity and Antibiotic Resistance Patterns

Abstract Introduction: Urinary tract infection (UTI) remains a prevalent bacterial infection among the pediatric age group, ranking as the third-most common bacterial infection in children in developing countries, following gastrointestinal and respiratory tract infections. It continues to pose a significant health challenge. Materials and Methods: The urine samples underwent gross examination, wet mount, and Gram stain. Semiquantitative cultures were conducted on conventional media (MacConkey agar, blood agar, and CLED agar) and UTI chromogenic media. Uropathogen identification employed standard microbiological techniques. Antibiotic susceptibility was determined using the Kirby–Bauer disk diffusion method, with interpretation based on CLSI guidelines. Plates were incubated overnight, and clear zone diameters around antibiotic discs were measured for sensitivity or resistance determination. Results: The study comprised 64.75% male children and 35.25% female children. Analyzing the age distribution, the majority of participants fell within the age range of 1–5 years (35%), followed by those <1 year (33.75%), and the age group of 5–12 years, accounting for 31.25% of the total 400 participants. The findings from our investigation revealed a UTI prevalence of 17.25%, with Escherichia coli and Klebsiella emerging as the predominant uropathogens. Notably, these pathogens exhibited a significant susceptibility to carbapenems, nitrofurantoin, and amikacin. Conclusion: Our study identified a male predominance and various age distributions among UTI patients. Antibiotic susceptibility patterns revealed E. coli and Klebsiella pneumoniae’s high sensitivity to key antibiotics, whereas Enterococcus spp. exhibited significant high-level aminoglycoside resistance. This study underscores the importance of tailored antibiotic strategies based on local resistance profiles to combat UTIs effectively.

Phenotypic characterization of ESBL-producing urinary isolates of E. coli and Klebsiella spp. in a tertiary care children's hospital in Nepal

BackgroundThe production of extended-spectrum beta-lactamases (ESBLs) among uropathogens, particularly E. coli and Klebsiella spp., poses a severe public health concern. This study explored the epidemiology of ESBL-producing E. coli and Klebsiella spp. isolated from urine samples obtained at a tertiary care children's hospital in Nepal.MethodsA cross-sectional study was conducted from August 2016 to February 2017. A total of 745 clean catch urine samples were obtained from pediatric patients under the age of 13 and subjected to semiquantitative culture. E. coli and Klebsiella spp. were identified using standard laboratory protocols. Antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method, and ESBL producers were phenotypically identified using the combined disk method.ResultsAmong the bacterial isolates, E. coli predominated, accounting for 139 (81.8%) positive cases. Notably, E. coli showed high susceptibility to nitrofurantoin, with 117 (84.2%) isolates being susceptible. Meanwhile, K. pneumoniae showed high susceptibility to gentamicin, with 21 (91.3%) isolates being susceptible. Of the 163 isolates of E. coli and Klebsiella spp., 62 (38.0%) were identified as multidrug-resistant (MDR), with 42 (25.8%) confirmed as phenotypic ESBL producers. Remarkably, all 41 (100%) ESBL-producing E. coli isolates were susceptible to imipenem.ConclusionsThe prevalence of ESBL producers among E. coli and K. pneumoniae isolates from pediatric patients underscores the importance of antimicrobial stewardship. Nitrofurantoin and gentamicin emerge as effective empirical treatment choices against these pathogens in children. However, the high rates of multidrug resistance and ESBL production highlight the necessity for routine surveillance, and early detection strategies to manage such infections effectively.

Microbiology of Severe Community-Acquired Pneumonia and the Role of Rapid Molecular Techniques.

The microbiology of severe community acquired pneumonia (SCAP) has implications on management, clinical outcomes and public health policy. Therefore, knowledge of the etiologies of SCAP and methods to identify these microorganisms is key. Bacteria including Streptococcus pneumoniae, Staphylococcus aureus and Enterobacteriaceae continue to be important causes of SCAP. Viruses remain the most commonly identified etiology of SCAP. Atypical organisms are also important etiologies of SCAP and are critical to identify for public health. With the increased number of immunocompromised individuals, less common pathogens may also be found as the causative agent of SCAP. Traditional diagnostic tests, including semi-quantitative respiratory cultures, blood cultures and urinary antigens continue to hold an important role in the evaluation of patients with SCAP. Many of the limitations of the aforementioned tests are addressed by rapid, molecular diagnostic tests. Molecular diagnostics utilize culture-independent technology to identify species-specific genetic sequences. These tests are often semi-automated and provide results within hours, which provides an opportunity for expedient antibiotic stewardship. The existing literature suggests molecular diagnostic techniques may improve antibiotic stewardship in CAP, and future research should investigate optimal methods for implementation of these assays into clinical practice.

A Comparative Evaluation of ESBL Production and Carbapenem Resistance in UTIs Before and During COVID-19

Background: The COVID-19 pandemic has heightened the urgency to address antibiotic resistance, particularly ESBL and carbapenem-resistant UTIs. Our study seeks to assess the pandemic's effect on the prevalence of these resistances, comparing data from before and during COVID-19. By identifying trends in resistance patterns, we aim to enhance antibiotic stewardship and inform healthcare policies. Understanding the pandemic's impact on ESBL and carbapenem resistance is vital for guiding clinical practices and public health initiatives in tackling antibiotic resistance. Methods: This retrospective study, conducted at King Fahad Medical City in Riyadh, Saudi Arabia, analyzed positive urine cultures from January 2018 to December 2022 to assess the prevalence of antibiotic resistance among UTIs. Using WHO-recommended semiquantitative culturing methods on CLED and blood agar, bacterial isolates were identified via the BD Phoenix system and antimicrobial susceptibility was assessed following CLSI guidelines. ESBL detection employed the Double-Disc Synergy Test. Data analysis involved SPSS for statistical evaluation, utilizing chi-square and t-tests for categorical and continuous variables, respectively, and logistic regression to explore associations between variables and antibiotic resistance, with significance set at p

691. Association between Clostridioides difficile Colonization, Rectal Swab NAAT Positivity, and Environmental Contamination

Abstract Background Clostridioides difficile (CD) colonization is common among hospitalized patients. Screening for toxigenic CD (TCD) colonization with rectal swab nucleic acid amplification tests (NAAT) may identify people at risk for CDI and help prevent onward TCD transmission, especially in immunocompromised patients with long hospitalizations. The study objective was to test whether rectal swab NAAT could detect TCD colonized patients and whether NAAT results identify patients that contribute to environmental contamination. Methods This was a prospective cohort study on two BMT/Leukemia units. Stool specimens, rectal swabs, and environmental swabs (bedrail, room sink, keyboard) were collected from patients at admission and weekly and cultured semi-quantitatively for TCD. NAAT (Cepheid) was performed on rectal swabs (eSwabs; Copan Diagnostics). The relationship between stool TCD concentration, NAAT Ct, and a positive environmental culture was evaluated using univariate logistic regression. Bleach was used for daily and terminal discharge cleaning of all rooms. Toxigenicity was determined by detection of tcdA or tcdB by whole genome sequencing (WGS). Results From January 2019 - July 2019, 659 stool specimens and 495 rectal swabs were collected from 384 patients. Specimens from 554 patient-days were cultured and 126 (23%) were positive. Of those, 88 (70%) were TCD. 21 of 987 (2%) environmental swabs were TCD positive; 18 (86%) were from bedrails. Among 61 unique patient calendar days with paired rectal swab NAAT and stool culture results (paired samples), overall sensitivity of rectal swab NAAT to detect toxigenic CD colonization compared to culture was 44%, with 4/16 (25%) of people colonized with > 0 - < 10,000 CFU/g of TCD and 7/9 (78%) with ≥ 10,000 CFU/g TCD (Figure 1). There was no relationship between stool culture or rectal swab NAAT result and risk of a positive environmental swab (Figure 2). Figure 1. Toxigenic C. difficile semi-quantitative culture and rectal swab NAAT on paired patient-day of specimen collection (N=61 patient-days) Figure 2. Toxigenic C. difficile semi-quantitative stool and rectal swab NAAT results and environmental contamination by paired patient-day of specimen collection Conclusion Rectal swab NAAT may not be sufficiently sensitive to screen for TCD colonization that contributes to environmental contamination. Disclosures Erik R. Dubberke, MD, MSPH, Abbott: Advisor/Consultant|AstraZeneca: Advisor/Consultant|Ferring Pharmaceuticals: Advisor/Consultant|Ferring Pharmaceuticals: Grant/Research Support|Merck and Co.: Advisor/Consultant|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Seres Therapeutics: Advisor/Consultant|Summit: Advisor/Consultant|Theriva Biologics: Grant/Research Support

Microbial Etiology and Resistance Patterns of Urinary Tract Infection at a Tertiary Care Centre – A Hospital based Study

Urinary tract infections (UTIs) are among the most common infections diagnosed in clinical practice. Treatment is often initiated before microbiological confirmation and anti-microbial susceptibility testing. With the rapidly rising antibiotic resistance treatment failures are not uncommon. Beta-lactamase production by gram-negative bacteria causing UTI is the commonest mode of drug resistance. The aim of current study was to detect and determine the hospital based prevalence of UTI, causative uropathogens and their antimicrobial susceptibility patterns. A total of 9,518 clean catch, mid stream urine samples were processed over 2 years. Semi-quantitative urine cultures and AST were performed. Diverse underlying resistance mechanisms were determined by detecting ESBLs, Carbapenemases, AmpC β-Lactamases, and Metallo-β-Lactamases through various standardized phenotypic methods. Out of the 9,518 samples tested 1171 (12.3%) were culture positive. Majority (66.7%) were from female patients. Highest prevalence (60%) was seen in patients > 40 years of age. E. coli (48%) was the predominant causative organism, followed by Enterococcus spp. (23%). Among GNB high resistance rates were observed against Beta-lactams, Beta-lactam/β-lactamase inhibitor combinations, and fluoroquinolones. 34.5% of GNB were confirmed as ESBL, 40% as carbapenemase, 36.5% as AmpC β-Lactamase, and 41.5% as MBL producers. We found very high levels of resistance against a broad range of antibiotics including the most widely used β-lactam group. With the resistance slopes getting steeper and steeper empirical treatment of UTIs might be fraught with the danger of many failures. Culturing and performing AST for all patients with UTI might be a prudent step for their rationale treatment and a step forward in halting the emergence of further resistance.

The impact of quantitative and semi-quantitative culture of respiratory tract secretions on clinical decisions in a patient with suspected pneumonia – case study

Pneumonia is one of the most common disease entities treated in the Intensive Care Unit. The standard diagnostic procedure for patients with suspected pneumonia is to evaluate the presence of symptoms of infection, physical examination, imaging, laboratory and microbiological tests, arterial blood gasometry and culture of respiratory tract secretions. In many Intensive Care Units, the preferred method of collecting material from the lower respiratory tract is an endotracheal aspirate. However, its semi-quantitative culture does not distinguish respiratory tract colonization from infection. Samples obtained by bronchoscopy are believed to be more representative of the presence of true pathogens in the lungs.
 An 87-year-old patient with myasthenia gravis was admitted to the Intensive Care Unit for suspected pneumonia. Laboratory tests showed elevated inflammatory markers and a chest X-ray showed interstitial densities in the left lower lobe. The result of semi-quantitative culture of tracheal aspirate was heavy growth of Staphylococcus aureus and heavy growth of Pseudomonas aeruginosa. The result of the quantitative BAL culture was S.aureus MSSA 105 colony-forming unit (CFU) per ml, Pseudomonas aeruginosa 102 CFU/ml. To consider a microorganism responsible for infection, the number of bacteria cells must exceed a designated threshold. For BAL it is ≥104 CFU/ml, for TA it is ≥106 CFU/ml, for PSB it is ≥ 103/ml. In this case, the cutoff point for identifying the pathogen responsible for the infection was reached only by Staphylococcus aureus (105 CFU/ml), not by Pseudomonas aeruginosa (102 CFU/ml).
 The final diagnosis was left-sided PN1 pneumonia of S.aureus etiology. A cloxacillin was used for the treatment. Clinical improvement was achieved.
 The described case proves the advantage of quantitative culture over semi-quantitative culture of respiratory tract secretions. The advantage of bronchoalveolar lavage over tracheal aspirate is also noticeable.

Comparison of microbial colonization rates between central venous catheters and peripherally inserted central catheters

BackgroundCentral venous catheters (CVCs) and peripherally inserted central catheters (PICCs), have been widely used as intravascular devices in critically ill patients. However, they might evoke complications, such as catheter colonization that has been considered as predisposing factor for central line-associated bloodstream infections (CLABSIs). Although numerous studies have compared the risk of bloodstream infections between PICCs and CVCs, comparative studies on their colonization rates are limited.ObjectivesThe episodes of catheter colonization in critically ill patients with CVCs or PICCs were retrospectively analysed during a two-year period in a Greek tertiary care hospital and colonization rates, microbial profiles and antimicrobial susceptibility patterns were compared.MethodsClinical and laboratory data of consecutive hospitalized critically-ill patients who underwent PICC and CVC placement between May 2017–May 2019 were analysed. All catheters were examined by the semiquantitative culture technique for bacterial pathogens, either as a routine process after catheter removal or after suspicion of infection. Species identification and antimicrobial resistance patterns were determined by the Vitek2 automated system.ResultsDuring the survey period a total of 122/1187 (10.28%) catheter colonization cases were identified among CVCs and 19/639 (2.97%) cases among PICCs (p = 0.001). The colonization rate was 12.48/1000 catheter-days for the CVC group and 1.71/1000 catheter-days for the PICC group (p < 0.001). The colonization rate per 1000 catheter-days due to multidrug-resistant organisms (MDROs) was 3.85 in all study cases, 7.26 (71/122) in the CVC group and 0.63 (7/19) in the PICC group (p < 0.001). Within the CVC group, the most common microorganism isolated was MDR Acinetobacter baumannii (n = 38, 31.1%) followed by MDR Klebsiella pneumoniae (n = 20, 16.4%). In the PICC group, the predominant microorganism isolated was Candida spp. (n = 5, 23.8%) followed by MDR K. pneumoniae and MDR A. baumannii in equal numbers (n = 3, 14.2%).ConclusionPICC lines were associated with significantly lower colonization rates comparing to the CVC ones. In addition, patterns of microbial colonization revealed a trend over the predominance of MDR gram-negatives in CVCs suggesting that PICCs might be a safer alternative for prolonged inpatient intravascular access. Prevention programs directed by local microbial ecology may diminish catheter colonization rates and CLABSIs.

Molecular Epidemiology of Streptococcus pneumoniae Detected in Hospitalized Pediatric Acute Respiratory Infection Cases in Central Vietnam.

Streptococcus pneumoniae is the major bacterial pathogen causing high pneumonia morbidity and mortality in children <5 years of age. This study aimed to determine the molecular epidemiology of S. pneumoniae detected among hospitalized pediatric ARI cases at Khanh Hoa General Hospital, Nha Trang, Vietnam, from October 2015 to September 2016 (pre-PCV). We performed semi-quantitative culture to isolate S. pneumoniae. Serotyping, antimicrobial susceptibility testing, resistance gene detection and multi-locus sequence typing were also performed. During the study period, 1300 cases were enrolled and 413 (31.8%) S. pneumoniae were isolated. School attendance, age <3 years old and prior antibiotic use before admission were positively associated with S. pneumoniae isolation. Major serotypes were 6A/B (35.9%), 19F (23.7%) and 23F (12.7%), which accounted for 80.3% of vaccine-type pneumococci. High resistance to Clarithromycin, Erythromycin and Clindamycin (86.7%, 85%, 78.2%) and the mutant drug-resistant genes pbp1A (98.1%), pbp2b (98.8%), pbp2x (99.6%) ermB (96.6%) and mefA (30.3%) were detected. MLST data showed high genetic diversity among the isolates with dominant ST 320 (21.2%) and ST 13223 (19.3%), which were mainly found in Vietnam. Non-typeables accounted for most of the new STs found in the study. Vaccine-type pneumococcus and macrolide resistance were commonly detected among hospitalized pediatric ARI cases.

Bacterial findings in patients referred to hospital for the treatment of acute tonsillitis with or without peritonsillar phlegmon

BackgroundThe vast majority of patients with acute tonsillitis (AT) are managed in general practice. However, occasionally patients are referred to hospital for specialized management because of aggravated symptoms and/or findings suggestive of peritonsillar involvement. No prospective studies have been conducted aiming to investigate the prevalent and significant microorganisms in this highly selected group of patients. We aimed to describe the microbiological findings of acute tonsillitis with or without peritonsillar phlegmon (PP) in patients referred for hospital treatment and to point out potential pathogens using the following principles to suggest pathogenic significance: (1) higher prevalence in patients compared to healthy controls, (2) higher abundance in patients compared to controls, and (3) higher prevalence at time of infection compared to time of follow up.MethodsMeticulous and comprehensive cultures were performed on tonsillar swabs from 64 patients with AT with (n = 25) or without (n = 39) PP and 55 healthy controls, who were prospectively enrolled at two Danish Ear-Nose-Throat Departments between June 2016 and December 2019.ResultsStreptococcus pyogenes was significantly more prevalent in patients (27%) compared to controls (4%) (p < 0.001). Higher abundance was found in patients compared to controls for Fusobacterium necrophorum (mean 2.4 vs. 1.4, p = 0.017) and S. pyogenes (mean 3.1 vs. 2.0, p = 0.045) in semi-quantitative cultures. S. pyogenes, Streptococcus dysgalactiae, and Prevotella species were significantly more prevalent at time of infection compared to follow up (p = 0.016, p = 0.016, and p = 0.039, respectively). A number of species were detected significantly less frequently in patients compared to controls and the mean number of species was significantly lower in patients compared to controls (6.5 vs. 8.3, p < 0.001).ConclusionsDisregarding Prevotella spp. because of the prevalence in healthy controls (100%), our findings suggest that S. pyogenes, F. necrophorum, and S. dysgalactiae are significant pathogens in severe AT with or without PP. In addition, infections were associated with reduced diversity (dysbacteriosis).Trial registrationThe study is registered in the ClinicalTrials.gov protocol database (# 52,683). The study was approved by the Ethical Committee at Aarhus County (# 1-10-72-71-16) and by the Danish Data Protection Agency (# 1-16-02-65-16).

Antibacterial effect of ethanolic fraction of Medicago sativa extract on Escherichia coli in urinary tract infection

Introduction and Aim: Uropathogenic E. coli infections of the urinary system have grown to be a serious global public health issue. Medicago Sativa has been reported to have antibacterial effects against a variety of harmful microorganisms. Hence, the aim of this study was to investigate M. sativa's potential antibacterial effectiveness against Escherichia coli isolated from urine samples in urinary tract infection patients visiting Medical city hospitals in Iraq/Baghdad. Material and Methods: During this study, urine samples were collected from 85 patients visiting various hospitals in Iraq, from December 2021 to May 2022. A semi-quantitative culture technique and a conventional microbiological approach was used to identify Escherichia coli in the urine samples. E.coli isolates were assessed for their antibiotic susceptibility using the Kirby-Bauer Disk diffusion method. The crude Medicago sativa plant extract was screened for its phytochemical constituents. Various ethanol fraction concentrations (25 mg/ml, 50 mg/ml, and 75 mg/ml) were tested for their inhibitory activity of uropathogenic E. coli. Results: Only 30 out of the 85 urine samples tested positive for uropathogenic E. coli. Among patients, UTI infection with E.coli was seen to be more prevalent in females than in males. The Medicago sativa extracts demonstrated considerable antibiotic activity against E. coli with a MIC of 25 mg/ml for ethanolic fraction. Conclusion: Based on this present study we conclude that Medicago sativa extracts have great potential as an antimicrobial agent against uropathogenic E. coli.

Antibacterial effect of ethyl acetate fraction of Medicago Sativa on Escherichia Coli in urinary tract infections

Background: One of the most dominant bacterial infections is urinary tract infection (UTI), both in the community and in the hospital settings Since drug resistance become one of the predominant problems of health worldwide, it is necessary to use new methods to overcome drug-resistant bacteria. In this regard, medicinal plants (Medicago sativa ) are considered one of the richest sources to produce antibiotics.&#x0D; Aim of the study: evaluate the antibacterial effect of the fraction of ethyl acetate of Medicago Sativa extract against Escherichia Coli isolated from urine samples of patients with urinary tract infections.&#x0D; Material and methods: throughout this study 85 urine samples were taken from patients attending one of the hospitals in Iraq's Medical City complex, the study was conducted between December 2021 and May 2022, Semi-quantitative culture techniques were used to culture the urine samples, and conventional microbiological methods were used to identify the bacteria. the Kirby-Bauer Disk diffusion method was used for testing antibiotic susceptibility. The antibacterial effect of Medicago Sativa was tested by preparing Medicago sativa crude extract in 85 percent ethanol in the soxhlet apparatus. The extract is then fractionated into ethyl acetate fraction, then the effectiveness against uropathogenic E. coli was tested at various concentrations (25 mg/ml, 50 mg/ml, and 75 mg/ml).&#x0D; Result: 60% of the population was female compared to 40% of the male in UTI patients with E.coli. Concerning age, the majority of study participants (20–39 years) were under 40 years old (56.7%), and all isolates show complete meropenem sensitivity. The extracts from Medicago Sativa showed significant antibacterial activity against E.Coli.&#x0D; Conclusion: Medicago sativa extracts have excellent potential as an antibacterial agent against uropathogenic E. coli, according to the current investigation findings.&#x0D; Keywords: Escherichia coli, Ethyl acetate fraction, Medicago sativa extract, UTIs

A BACTERIOLOGICAL STUDY OF URINARY TRACT INFECTION INVOLVING CULTURAL ANALYSIS

Background: Urinary Tract Infections are a common occurrence in the community and hospital and are associated with profound morbidity and decreased productivity at work. Timely diagnosis of UTI by cultural analysis is imperative in order to identify the offending agent and to initiate appropriate antimicrobial therapy. Objectives: The present study aimed at evaluating the bacteriological prole of UTI employing semiquantitative culture and to determine the antibiogram pattern of the bacteria isolated. Methods: The study was conducted on 200 urine samples, collected from clinically suspected cases of UTI. Semiquantitative analysis was done and antimicrobial sensitivity testing undertaken, as per CLSI guidelines. Results: Signicant bacteriuria was observed in 66.5% cases. Gram negative bacilli were predominant pathogens (71.3%), amongst which, Escherichia coli and Klebsiella pneumoniae were the main agents (37.2% and 24.5 % respectively). Gram positive organisms accounted for 28.7% of the total; Enterococcus species being the predominant isolate type (78.04%; 32 out of 41 gram positive pathogens). Overall, Escherichia coli predominated (26.6%), followed by Enterococcus species (22.4%). Gram negative bacilli showed good sensitivity to Imipenem and Aminoglycosides. Gram positive cocci were all sensitive to Vancomycin and Linezolid. A large number of cases were 50 years and above (51%), followed by age groups 21-30 years (17.5%) and 31 to 40 years (16.5%). The Male: Female ratio was 1.2:1, males accounting for 53.5% of the total. Conclusion: Early cultural analysis of UTI cases with identication of the etiological agent and its antibiogram pattern will help in early treatment and use of appropriate antibiotics. This will reduce the use of empirical treatment, morbidity and chronicity

Evaluation of an automated rapid urine culture method for urinary tract infection: Comparison with gold standard conventional culture method.

Urinary tract infection is one of the most prevalent disease affecting people from all age groups. For its diagnosis, conventional culture and antibiotic susceptibility is the gold standard. However, its major limitation is that the results take minimum of 24​h and antibiotic susceptibility is available after 48​h. Automated culture methods having comparable sensitivity and specificity as compared to conventional culture should be evaluated for routine diagnostics. With this aim we evaluated the diagnostic accuracy of automated urine culture method HB&L uroquattro by comparing with the gold standard conventional culture method. A total of 1220 urine samples were included in the study. Semi-quantitative urine culture was performed using standard methods on cysteine lactose electrolyte deficient medium. For the automated culture, HB&L Uroquattro (Alifax, Polverara, PD, Italy), standard guidelines given in the manual of the instrument were followed. Diagnostic performance in terms of sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values were calculated. Based on the final interpretation of conventional culture for the total 1220 samples, 26 samples (2.1%) showed major non-concordance as they were identified as sterile by HB&L but had significant growth by conventional culture and 19.9% showed minor non-concordance. At 100-999 colony forming unit/ml, HB&L has high negative predictive value i.e. 96.6% with 95% CI (95.2%-97.6%) and sensitivity i.e. 92.66% with 95% CI of (89.42%-95.15%). The HB&L Uroquattro seems to be a reliable instrument to obtain urine microbiological results in a timely manner. This technique can give presumptive report to the clinician within 5​h only for initiation of empirical antibiotics in cases of positive results.

Nitrite-negative results in urinary tract infection by Enterobacterales: does the nitrite dipstick test have low sensitivity?

Urinary tract infection (UTI) is one of the most common bacterial infections among humans. Urine culture is the gold standard diagnostic method for UTI; however, the dipstick test for nitrite is a widely used method signalling the presence of urinary nitrate-reducing bacteria. Unlike the gold standard, the dipstick test is easy to perform, while it is also less time-consuming and less expensive, and produces a result in a few minutes. This study investigates the sensitivity of the dipstick test for nitrite compared with the Griess test in urine samples from UTI caused by Enterobacterales species. We used the Griess test, which is the gold standard in nitrite measurement, to determine the sensitivity of the nitrite dipstick test. Semiquantitative urine culture was performed using standard procedures, and Enterobacterales identification was performed by manual conventional biochemical tests. In the first sample selection, 3 % (8/267) of urine samples suspected of UTI, analysed from March to April 2016, were nitrite-negative by dipstick test but positive for Enterobacterales in the urine culture. In the second sample selection, 5 % (2/44) of urine samples from October to December 2022 were also nitrite-negative but showed urine Enterobacterales isolation. All nitrite-negative dipstick results were consistent with the Griess test. Escherichia coli was the most prevalent bacterium, followed by Klebsiella pneumoniae, independent of sample selection. The dipstick test is a safe alternative for investigating nitrite in urine samples. We believe that the cause of nitrite-negative results is a lack of dietary nitrate, dilution of urine and exogenous interference (e.g. ascorbic acid). These findings support the idea that standard urine culture is necessary to rule out UTI.

Experience with the use of an automated system for diagnosis of urinary tract infections

Objective. To compare results of microbiological examination obtained on rapid automated system with semiquantitative plate culture to assess possibility and necessity of using the system in urine examination. Materials and Methods. The study included 231 urine samples collected from February to July 2023 from patients at Lomonosov Moscow State University Medical Research and Educational Center. The samples were cultured according to the standards of urine microbiological examination using chromogenic media and using an automatic HB&amp;L system (Alifax, Italy) for 4 h. 30 min. to detect bacteriuria of 102 CFU/ ml or more and residual antimicrobial activity. When microbial growth was detected in the analyzer, extraction of microorganisms was performed on the same day for accelerated identification. Identification was performed by MALDI-TOF mass spectrometry. Results. According to the plate culture method, 160 positive samples were obtained. A total of 273 isolates were isolated, the predominant microorganisms were E. faecalis (22.3%) and E. coli (19.8%), a significant part was composed of atypical pathogens for UTI and normobiota (33.7%). According to the rapid automated system, only in 100 samples the growth of microorganisms was detected, in 4 cases the positive result obtained by the automatic system was not confirmed by growth on chromogenic media. Thus, 64 of the 160 positive cultures were not detected using the automated system, and 14 of those ones was E. coli. Residual antimicrobial activity was detected in 104 samples, including 43 of 64 false-negative culture results using the automated system. Rapid identification was performed on 57 samples, a microbial identification result was obtained in 49 of them. Complete or partial match between the results of rapid identification and classical methods was obtained for 48 samples. In all cases, when rapid identification was performed for a sample with monoculture, the results of two methods were identical. Conclusions. An overall sensitivity and specificity of the culture method using an automatic system were 60% and 94.4%, respectively. Sensitivity for samples containing E. coli was 74.1%, and for their isolation in monoculture – 87.5%.

Culturing explants for Cutibacterium at revision shoulder arthroplasty: an analysis of explant and tissue samples at corresponding anatomic sites.

Culturing of deep tissues obtained at revision arthroplasty for Cutibacterium is a key component of diagnosing a periprosthetic infection. The value of culturing explanted components has not been well described. This study sought to answer the following questions: (1) How does the culture positivity of explant cultures compare with that of deep tissue cultures? (2) How often are explant cultures positive when tissue cultures are not, and vice versa? (3) How does the bacterial density in explant cultures compare with that in tissue cultures? A total of 106 anatomic arthroplasties revised over a 7-year period were included. Explant (humeral head, humeral stem, and glenoid) and tissue (collar membrane, humeral canal tissue, and periglenoid tissue) specimens were sent for semiquantitative Cutibacterium culture. We compared culture positivity and bacterial density when cultures of an explant and tissue adjacent to the implant were both available. Explants had positive cultures at a higher rate than adjacent tissue specimens for most anatomic sites. Of the shoulders that had Cutibacterium growth, a higher proportion of explants were culture positive when tissue samples were negative (23%-43%) than vice versa (0%-21%). The Cutibacterium density was higher in explants than in tissues. Considering only the results of tissue samples, 16% of the shoulders met our threshold for infection treatment (≥2 positive cultures); however, with the inclusion of the results for explant cultures, additional 14% of cases-a total of 30%-met the criteria for infection treatment. In this group of patients, culturing explants in addition to tissue cultures increased the sensitivity for detecting Cutibacterium in revision shoulder arthroplasty.