Quantitative Bacterial Cultures Research Articles

Comparative analysis of different loop types for urine culture collection: Implications for quantitative bacterial growth and culture results

We hypothesized that the loop material and size could affect the results of the culture when compared to the calibrated pipette. A total of 484 urine samples were included in the study, and each sample was plated by using different loop types and the calibrated pipette. The bacterial counts per milliliter were calculated and compared, with a focus on the important cutoff values of 10³ and 10⁴ CFU/ml for further identification. When considering the 10³ CFU/ml as cutoff value, 1 µl and 10 µl plastic loops gave the highest sensitivity (86.8 %), whereas the 10 µl metal loop had the lowest sensitivity (64.2 %). For the 10⁴ CFU/ml cutoff value, 1 µl plastic loop inoculation demonstrated the highest sensitivity (75.9 %), while the 10 µl metal loop provided the lowest sensitivity (26.5 %). These results suggest that the single use plastic loops are functional, sensitive, useful especially for critical sample.

Prevention of legionella infections from toilet flushing cisterns

INTRODUCTIONImmunocompromised patients are at an increased risk of severe Legionella infections. We present the results of an outbreak investigation initiated following a fatal case of hospital-acquired legionellosis linked to contaminated water from a toilet-flushing cistern. Additionally, we provide experimental data on the growth of Legionella spp. in flushing cisterns and propose a straightforward protocol for prevention. METHODSWe monitored the growth of Legionella spp. in the building's hot and cold-water systems using quantitative bacterial culture on selective agar. Molecular typing of L. pneumophila isolates from the infected patient and the water system was conducted through core-genome multilocus sequence typing (cgMLST). RESULTSLegionella contamination in the hospital building’s cold-water system was significantly higher than in the hot water system and significantly higher in toilet flushing cistern’s water compared to cold water from bathroom sinks and showers. Isolates from the patient and from the flushing cistern of the patient’s bathroom were identical by cgMLST. In an experimental setting, daily toilet flushing for a period of 21 days resulted in a 67 percent reduction in the growth of Legionella spp. in the water of toilet flushing cisterns. Moreover, a one-time disinfection of cisterns with peracetic acid, followed by daily flushing, decreased Legionella growth to less than 1% over a period of at least 7 weeks in these setting. CONCLUSIONSOne-time disinfection of highly contaminated cisterns with peracetic acid and daily toilet flushing as short-term measure can significantly reduce Legionella contamination in flushing cisterns. These measures may aid in preventing Legionella infection among immunocompromised patients.

Utility of dipstick urinalysis in the diagnosis of urinary tract infections among outpatients in Mwanza and Dar es Salaam regions in Tanzania

Abstract Background Globally, urinary tract infections (UTIs) are the leading cause of hospital visits, especially among women. In many developing countries, especially in lower health facilities, the dipstick urinalysis is the most commonly requested test, as urine culture is not routinely performed. The dipstick test can potentially reduce the number of patients who could be treated with empirical antibiotics and reduce the burden of antibiotic resistance. The current study determined the utility of dipstick urinalysis in diagnosing UTIs using urine culture as a gold standard method. Methods A cross-sectional study was conducted between July and November 2021. The study involved 1327 outpatients attending lower health centres in Mwanza (n = 678) and Dar es Salaam (n = 649) regions. The samples were subjected to dipstick urinalysis (nitrite and leucocytes) and quantitative bacterial culture. Results Of all 1326 patient samples, 808(60.9%) and 48(3.6%) were positive for urinary leucocyte and nitrite, respectively, while significant urine culture was found in 364(27.4%). leucocyte test correctly diagnosed UTI in 283 (77.75%) and nitrite test in 36 (9.89%). The leucocytes and nitrites, in combination, exhibited a sensitivity of 79.40% and NPV of 85.24% but a lower specificity of 44.96% and a lower PPV of 35.29%. Urinary leucocyte test had a higher discrimination ability to detect urinary tract infection than urinary nitrite test (AUC = 0.073, 95% CI 0.043–0.103, p < 0.001); likewise, combined results of urinary nitrite and leucocytes tests had higher discrimination ability to detect UTI than nitrite only (AUC = − 0.079, 95% CI − 0.107–0.050, p < 0.001). Conclusions In settings where culture is available, dipstick urinalysis can be a helpful screening method for reducing unnecessary urine cultures and related expenses because of its higher negative predictive value. In most low-resource settings where patients' diagnosis solely depends on clinical diagnosis and culture is not easily available, urine dipstick can decrease the risk of overuse of antibiotics. However, the combined (leucocytes and nitrites) dipstick urinalysis has a rather low positive predictive value, with approximately one-third of cases giving positive test results being truly UTI, subjecting over 65% of cases to unnecessary antibiotic treatment.

Impact of surface receptors TLR2, CR3, and FcγRIII on Rhodococcus equi phagocytosis and intracellular survival in macrophages.

The virulence-associated protein A (VapA) produced by virulent Rhodococcus equi allows it to replicate in macrophages and cause pneumonia in foals. It is unknown how VapA interacts with mammalian cell receptors, but intracellular replication of avirulent R. equi lacking vapA can be restored by supplementation with recombinant VapA (rVapA). Our objectives were to determine whether the absence of the surface receptors Toll-like receptor 2 (TLR2), complement receptor 3 (CR3), or Fc gamma receptor III (FcγRIII) impacts R. equi phagocytosis and intracellular replication in macrophages, and whether rVapA restoration of virulence in R. equi is dependent upon these receptors. Wild-type (WT) murine macrophages with TLR2, CR3, or FcγRIII blocked or knocked out (KO) were infected with virulent or avirulent R. equi, with or without rVapA supplementation. Quantitative bacterial culture and immunofluorescence imaging were performed. Phagocytosis of R. equi was not affected by blockade or KO of TLR2 or CR3. Intracellular replication of virulent R. equi was not affected by TLR2, CR3, or FcγRIII blockade or KO; however, avirulent R. equi replicated in TLR2-/- and CR3-/- macrophages but not in WT and FcγRIII-/-. rVapA supplementation did not affect avirulent R. equi phagocytosis but promoted intracellular replication in WT and all KO cells. By demonstrating that TLR2 and CR3 limit replication of avirulent but not virulent R. equi and that VapA-mediated virulence is independent of TLR2, CR3, or FcγRIII, our study provides novel insights into the role of these specific surface receptors in determining the entry and intracellular fate of R. equi.

The impact ofurine storage methods onthe results ofquantitative bacterial culture indog and cat.

Quantitative bacterial culture (QBC) isthe gold standard for determining urinary tract infections. However, the majority ofurine samples were sent toalab for further bacterial culture. Therefore, the storage condition was vital tomaintain the quality and accuracy ofthe urine samples. The main objective ofour study was toexamine the urine QBC outcomes of(1) immediate culture, (2) culture after urine sample storage atambient temperature for 24 h, and (3) culture after urine sample storage at4°C for 24hours. There were 49 feline samples and 30 canine samples included inthis study. All QBC samples kept atambient temperature and refrigerator were consistent with immediate QBC incats. Eight positive results from immediate QBC were inaccordance with refrigerated results indogs. There were ten positive results inthe room-temperature sample with two false-positive results. Our study showed that storing conditions atroom temperature orrefrigeration for 24 h does not impact the results ofQBC incat urine samples. For dog samples, chilled samples have ahigher accuracy rate than room temperature samples, although the overall agreement was still satisfactory.

Clinical impact of a multiplex rapid diagnostic pneumonia panel in critically ill patients.

To evaluate the clinical impact of the BioFire FilmArray Pneumonia Panel (PNA panel) in critically ill patients. Single-center, preintervention and postintervention retrospective cohort study. Tertiary-care academic medical center. Adult ICU patients. Patients with quantitative bacterial cultures obtained by bronchoalveolar lavage or tracheal aspirate either before (January-March 2021, preintervention period) or after (January-March 2022, postintervention period) implementation of the PNA panel were randomly screened until 25 patients per study month (75 in each cohort) who met the study criteria were included. Antibiotic use from the day of culture collection through day 5 was compared. The primary outcome of median time to first antibiotic change based on microbiologic data was 50 hours before the intervention versus 21 hours after the intervention (P = .0006). Also, 56 postintervention regimens (75%) were eligible for change based on PNA panel results; actual change occurred in 30 regimens (54%). Median antibiotic days of therapy (DOTs) were 8 before the intervention versus 6 after the intervention (P = .07). For the patients with antibiotic changes made based on PNA panel results, the median time to first antibiotic change was 10 hours. For patients who were initially on inadequate therapy, time to adequate therapy was 67 hours before the intervention versus 37 hours after the intervention (P = .27). The PNA panel was associated with decreased time to first antibiotic change and fewer antibiotic DOTs. Its impact may have been larger if a higher percentage of potential antibiotic changes had been implemented. The PNA panel is a promising tool to enhance antibiotic stewardship.

Bacteriological Analysis of Bronchoalveolar Lavage Fluid in Patients with Respiratory Tract Infections

Background and Aim: Bacterial respiratory infections are most commonly causes of illness for all age group patientsin ICU. Most of the patients suffer from urosepsis, postoperative disease and lower respiratory infection whenadmitted in ICU’s. Broncho alveolar lavage (BAL) is an ideal sample that allows the recovery of pathogens cellularand noncellular components from the epithelial surface of lower respiratory tract. This study was performed todetect pathogenic organisms by microscopy of BAL fluid and isolate and identify various bacteria and fungi fromBAL fluid in culture and analyze their antibiogram.Material and Methods: The cross-sectional prospective study was conducted in the Department of Microbiology,tertiary care teaching hospital, India. The study included 200 BAL samples taken from all consecutive patientsreferred with suspicion of pneumonia. Bronchial wash was done with the help of fibreoptic bronchoscope underlocal anaesthesia. All BAL samples were cultured on three bacteriological media agar plates using a sterile 4mmnichrome loop (0.01ml), and incubated at 37 C for 72 hours for quantitative bacterial culture using standardlaboratory techniques. Bacterial isolates were identified by performing standard microbiological procedures suchas study of colony morphology, Gram staining and standard biochemical tests.Results: Out of the total 200 samples, 120 (60%) were from males, and 80 (40%) were female patients. Thepredominant GNB was Klebsiella pneumoniae 45 (61%), followed by Pseudomonas aeruginosa 22(30%), Esch.coli 6(8%) and the fungal isolate was Aspergillus niger 5(1%). Klebsiella & Pseudomonas were highly sensitive toamikacin, piperacillin-tazobactam, imipenem, gentamycin, followed by tobramycin.Conclusion: Results of the present study demonstrate the high incidence of gram-negative isolates. The study alsosuggests that regular antimicrobial sensitivity monitoring should be done as most isolates are highly resistant tocephalosporin and other commonly used antimicrobials

Bacteriological Profile of Clinical Isolates from Urinary Samples and Prevalence of CAUTI at a Tertiary Care Hospital

Background: Urinary tract infections (UTIs) attributed to the use of an indwelling catheter is one of the most common infections acquired by patients in health care facilities. This infection is associated with varied microbiological etiology. Catheter-associated urinary tract infection (CAUTI) is an important cause of morbidity and mortality in India. The objective of this study was to find the prevalence of CAUTI infection and to determine their antibiotic profile. Aims and Objectives: The aim of the study was to provide a baseline information in the context of culture positivity rate of urinary isolates and prevalence of catheter associated urinary tract infections (CAUTI), to identify the associated microbial, and to determine their susceptibility pattern to commonly used antimicrobial agents for prophylactic and empiric therapy. Materials and Methods: This prospective study was done on nonrepetitive urine samples from all age group patients of both inpatient and outpatient department. Semi quantitative bacterial culture was performed, and isolates were identified and antimicrobial sensitivity tests were carried out by Vitek-2 compact automated method. Results: Significant bacteriuria was observed among 257/1543 (16.65%) urine samples. Among bacterial isolates, Gram negative bacilli predominate. Escherichia coli 7/17 (44%) being the most common isolate followed by Klebsiella (35%). The incidence of CAUTI/1000 catheter days observed in our study was 2.77. Total 3 CAUTI were identified from July 2021 to June 2022, out of which 2 were Klebsiella pneumoniae and 1 isolate was Enterococcus faecium. Conclusions: Uropathogens from CAUTI patients exhibit significantly higher resistance to most antibiotics than non- CAUTI isolates. This is an important factor to take into consideration when choosing correct treatment options for patients with urinary tract infection. Klebsiella pneumoniae is one of the important notable pathogens causing nosocomial infections.............

Association between quantitative bacterial culture of bronchoalveolar lavage fluid and antibiotic requirement in dogs with lower respiratory tract signs.

BackgroundHistorically, positive bacterial cultures from the lower respiratory tract (LRT) have been considered clinically relevant when quantitative bacterial cultures of bronchoalveolar lavage fluid (BALF) were >1700 colony forming units (cfu)/mL. However, this threshold might not accurately predict a requirement for antibiotics.ObjectivesTo study whether quantitative BALF bacterial culture results were predictive of antibiotic requirement in dogs with LRT signs.AnimalsThirty‐three client‐owned dogs.MethodsCross‐sectional study. Dogs with positive quantitative bacterial culture of BALF were included. Dogs were divided into 2 groups, depending on whether they had a LRT infection requiring antibiotics (LRTI‐RA) or LRT disease not requiring antibiotics (LRTD‐NRA), based on thoracic imaging features, presence of intracellular bacteria on BALF cytology, and response to treatment. Predictive effect of cfu/mL and BALF total nucleated cell count (TNCC) on antibiotic requirement, adjusting for ongoing or prior antibiotic therapy and age, were studied using logistic regression.ResultsTwenty‐two and 11 dogs were included in the LRTI‐RA and LRTD‐NRA groups, respectively. The cfu/mL was not significantly predictive of antibiotic requirement, independent of ongoing or prior antibiotic treatment and age (LRTI‐RA: median, 10 000 cfu/mL; range, 10‐3 × 108; LRTD‐NRA: median, 10 000 cfu/mL; range, 250‐1.3 × 109; P = .27). The TNCC was not significantly predictive of antibiotic requirement when only dogs with bronchial disease were considered (LRTI‐RA: median, 470 cells/μL; range, 240‐2260; LRTD‐NRA: median, 455 cells/μL; range, 80‐4990; P = .57).Conclusion and Clinical ImportanceThe cfu/mL is an inappropriate measure for determining whether antibiotics are of benefit in dogs with LRT signs.

Bacterial biogram in COVID-19 patients in Menoufia University isolation hospitals

Background The evaluation of coronavirus disease 2019 (COVID-19) patients with respiratory secondary bacterial infection, and the causative pathogens, is crucial for the treatment plan of those patients and to ensure the effective needed treatment with antibiotics and to decrease its abuse. Aim To clarify the incidence of bacterial infection in patients with COVID-19 and sensitivity to antibiotics. Patients and methods Samples of sputum were collected from 120 patients with confirmed COVID-19 by clinical, laboratory, radiological signs of pneumonia, or PCR, the severity of COVID-19 was classified as moderate and severe. The moderate type included patients with pneumonia without hypoxemia. The severe type was characterized by (a) dyspnea (respiratory rate ≥30/min), (b) blood oxygen saturation less than or equal to 93%, and (c) PaO2/FiO2 ratio less than 300 or lung infiltrates more than 50%. If one of the above items was met, it was classified as severe. Then, all cases were sent for screening of the presence of secondary bacterial infections by quantitative sputum bacterial culture and sensitivity. Positive cases of bacterial infection were classified into patients with early bacterial infection less than 15 days from COVID-19 infection and patients with late bacterial infections after more than 15 days of COVID-19 infection. Results In total, 40 (33.3%) cases out of 120 cases of COVID-19 showed bacterial growth, while 80 (66.7%) cases were negative for bacterial secondary infection. The most common organisms isolated were Klebsiella pneumoniae 12 cases, streptococci 10 cases, MERSA eight cases, Escherichia coli five cases and mixed infection by E. coli, Klebsiella, and Candida in five cases, Staphylococcus aureus was the same rate in early and late infections, all streptococci were early infection, and more cases of K. pneumoniae were late infection nine cases out of 13, where E. coli was early infection four cases out of five. All mixed infections were late. Conclusion Hidden secondary bacterial infection should be screened in COVID-19 patients. Early bacterial infections and moderate COVID-19 pneumonia are mainly caused by Gram-positive bacteria, but late bacterial infections and severe COVID-19 pneumonia are mainly caused by Gram-negative bacteria.

Outcomes of Mechanically Ventilated Patients With Nosocomial Tracheobronchitis.

IntroductionVentilator-associated tracheobronchitis is a condition that occurs prior to the development of ventilator-associated pneumonia among patients who have been intubated. This study aimed to determine the impact of nosocomial tracheobronchitis (NTB) related to new bacteria on the outcome in patients with chronic obstructive pulmonary disease (COPD).MethodologyA prospective, observational study was conducted in the department of surgical ICU of a tertiary care hospital between May 2019 and December 2019. All patients ventilated, irrespective of age and gender, were enrolled in the study. Individuals who had nosocomial pneumonia, before or followed by NTB, were excluded. Throughout the study, endotracheal aspirates for quantitative bacterial cultures were obtained routinely on admission, weekly thereafter, and whenever NTB or nosocomial pneumonia was suspected. All data were prospectively collected by the researchers from admission day till discharge or death of the patient. The outcomes of NTB patients were compared with those without NTB.ResultsA total of 24 patients with NTB and 214 patients without NTB were evaluated. There were a total of 24 patients who were diagnosed with NTB and 214 patients were NTB negative. There was a dominance of the male gender in the NTB group; however, the difference was not significant. The most common complication in patients was renal failure. During hospitalization, the Aspergillus tracheobronchitis (ATB) rate was significantly higher in patients with NTB as compared to patients with no NTB, i.e., 18 (75%) vs. 80 (37.4%) (p < 0.001). The mean length of stay in patients with NTB was significantly greater than the NTB negative group (p < 0.0001). The mortality in the case group was significantly greater than in the NTB negative group, i.e., 66.67% vs. 48.50% (p = 0.03).ConclusionNTB is associated with an increased duration of mechanical ventilation and hospitalization in intensive care units. The mortality rate in the NTB group was considerably higher than in the patients who did not have NTB. Future studies can explore the interventional and management aspect of the disease, such as determining whether early administration of broad-spectrum antibiotics can help improve the prognostic outcome of patients with NTB on mechanical ventilation.

The effect of urine storage temperature and boric acid preservation on quantitative bacterial culture for diagnosing canine urinary tract infection

BackgroundQuantitative bacterial culture (QBC) is the gold standard for diagnosing canine urinary tract infection. Current guidelines recommend QBC within 24 h of urine collection and that unpreserved urine is refrigerated until culture. However, temperature-controlled transport is rarely feasible, indicating a need for alternative storage during transport of urine from primary veterinary practices to the microbiology laboratory.The objective was to investigate the effect of storage temperature and boric acid sponge-preservation on quantitative bacterial culture of canine urine.ResultsSignificant bacteriuria was detected in 72 out of 179 samples (40%) collected from 141 dogs. Overall accuracy was 94–98% for both storage conditions and time points. Non-inferiority (15% margin) to reference quantitative bacterial culture was evident for sensitivity, specificity and predictive values for both storage methods and time points, except for the negative predictive value for 48 h boric acid preservation (NPV: 89, 95% CI [79;95]). There was no significant difference between the sensitivity and specificity for either of the time-points (p-value = 0.07–1).ConclusionsBoric acid sponge-preservation using Uriswab™ is a useful alternative to refrigeration of urine samples during transport. Reliable quantitative bacterial culture results can be obtained from canine urine up to 48 h after collection if urine is refrigerated, and for at least 24 h if urine is stored using a boric acid-containing urine transport system.

Pathogen distribution and bacterial resistance in children with severe pneumonia: A single-center retrospective study.

To examine the etiological distribution of pathogens in pediatric patients with severe pneumonia and analyze the drug resistance of major pathogen species.Nasopharyngeal secretion specimens were collected for bacterial culture from pediatric patients admitted to the Xiamen children's hospital who were diagnosed with severe pneumonia from January 2016 to December 2019. Pathogen species were detected by quantitative polymerase chain reaction, direct immunofluorescence, and bacterial culture and we examined the drug susceptibility of the bacterial pathogens.At least 1 species of the pathogen was detected in 576 of 734 patients and a total of 444 bacterial samples were isolated, of which 284 were gram-negative and 160 were gram-positive. The most frequently detected bacteria were Haemophilus influenzae, Streptococcus pneumonia, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. In addition, we isolated 186 viral samples, of which the majority were respiratory syncytial virus (n = 90) and adenovirus (n = 70) as well as 142 Mycoplasma pneumonia samples.Gram-negative bacteria are dominant among the pathogens causing severe pneumonia in pediatric patients and the major pathogen species are resistant to a variety of antibiotics. Appropriate antibiotic use has an important role in preventing the emergence of resistant strains.

NeoCLEAN: a multimodal strategy to enhance environmental cleaning in a resource-limited neonatal unit

BackgroundContamination of the hospital environment contributes to neonatal bacterial colonization and infection. Cleaning of hospital surfaces and equipment is seldom audited in resource-limited settings.MethodsA quasi-experimental study was conducted to assess the impact of a multimodal cleaning intervention for surfaces and equipment in a 30-bed neonatal ward. The intervention included cleaning audits with feedback, cleaning checklists, in-room cleaning wipes and training of staff and mothers in cleaning methods. Cleaning adequacy was evaluated for 100 items (58 surfaces, 42 equipment) using quantitative bacterial surface cultures, adenosine triphosphate bioluminescence assays and fluorescent ultraviolet markers, performed at baseline (P1, October 2019), early intervention (P2, November 2019) and late intervention (P3, February 2020).ResultsEnvironmental swabs (55/300; 18.3%) yielded growth of 78 potential neonatal pathogens with Enterococci, S. marcescens, K. pneumoniae, S. aureus and A. baumannii predominating. Highest aerobic colony counts were noted from moist surfaces such as sinks, milk kitchen surfaces, humidifiers and suction tubing. The proportion of surfaces and equipment exhibiting no bacterial growth increased between phases (P1 = 49%, P2 = 66%, P3 = 69%; p = 0.007). The proportion of surfaces and equipment meeting the ATP “cleanliness” threshold (< 200 relative light units) increased over time (P1 = 40%, P2 = 54%, P3 = 65%; p = 0.002), as did the UV marker removal rate (P1 = 23%, P2 = 71%, P3 = 74%; p < 0.001).ConclusionRoutine environmental cleaning of this neonatal ward was sub-optimal at baseline but improved significantly following a multimodal cleaning intervention. Involving mothers and nursing staff was key to achieving improved environmental and equipment cleaning in this resource-limited neonatal unit.

Detection of Mycobacterium avium subspecies paratuberculosis in environmental samples from infected Czech dairy herds

The objective of the present study was to evaluate the suitability of environmental sampling to screen Czech dairy herds to detect Mycobacterium avium ssp. paratuberculosis (MAP) and to find the most convenient location for the MAP detection in the lactating cow area. Environmental samples (ES, n = 72) from milking parlour holding pens (n = 19), milking alleyways (n = 19) and free-stall alleyways (n = 34) from 19 herds were simultaneously tested to detect MAP by a quantitative PCR (qPCR) and bacterial culture. Eight and thirteen samples from the milking parlour holding pens, twelve and eleven samples from the milking alleyways and eleven and eighteen samples from the free-stall alleyways were qPCR and culture positive, respectively. A 4.6 times higher probability of being culture positive than qPCR positive was detected for the assessable MAP detection results from the free-stall alleyways [P = 0.008 6, odds ration (OR) = 4.572 8)] and no association was found between the results from the milking parlour holding pens (P = 0.191 4) and the milking alleyways (P &amp;gt; 0.999 9) and the diagnostic method used. The percentage of qPCR-positive samples in the tested locations was detected for the milking alleyways (63.2%), free-stall alleyways and milking parlour holding pens. The herd infectious status was in agreement with 16 (84.2%), 14 (73.7%) and 12 (63.2%) qPCR results from the milking alleyways, free-stall alleyways (32.4%) and milking parlour holding pens (42.1%), respectively. No statistically significant differences were detected for these results (P = 0.396 1). MAP was detected by the qPCR and bacterial culture in all three locations where the ES were collected. We suggest an environmental sampling followed by MAP detection by qPCR as an easy-to-perform time-saving protocol for MAP screening in Czech dairy herds. Although the milking alleyways seem to be the most convenient location for the environmental sampling, this assumption was not statistically supported.

Antimicrobial Efficacy of Aqueous Ozone and Ozone-Lactic Acid Blend on Salmonella-Contaminated Chicken Drumsticks Using Multiple Sequential Soaking and Spraying Approaches.

Ozone (O3) is an attractive alternative antimicrobial in the poultry processing industry. The optimal operational conditions of O3 for improving food safety concerns are poorly understood. The main objective of this study was therefore to characterize the microbial killing capacity of aqueous O3 and O3–lactic acid blend (O3–LA) at different operational conditions on chicken drumsticks contaminated with high Salmonella load using sequential soaking and spraying approaches. Four hundred forty-eight chicken drumsticks (280–310 g) were soaked into two-strain Salmonella cocktail, and the initial load on the surface of the skin was 6.9-log10 cell forming unit (CFU)/cm2 [95% confidence interval (CI), 6.8–7.0]. The contaminated drumsticks were then sequentially (10×) soaked and sprayed with aqueous O3 (8 ppm) and O3–LA. Following O3 exposure, quantitative bacterial cultures were performed on the post-soaking and post-spraying water, skin surface, and subcutaneous (SC) of each drumstick using 3MTM PetrifilmTM Rapid Aerobic Count Plate (RAC) and plate reader. The average killing capacity of aqueous O3/cycle on the skin surface was 1.6-log10/cm2 (95% CI, 1.5–1.8-log10/cm2) and 1.2-log10/cm2 (95% CI, 1.0–1.4-log10/cm2), and it was 1.1-log10/cm2 (95% CI, 0.9–1.3-log10/cm2) and 0.9-log10/cm2 (95% CI, 0.7–1.1-log10/cm2) in SC for soaking and spraying approaches, respectively. Six sequential soaking and seven sequential spraying cycles with ozonated water of 8 ppm reduced the heavy Salmonella load below the detectable limit on the skin surface and SC of drumsticks, respectively. Addition of LA seems to increase the microbial killing capacity of aqueous O3 with average differences of 0.3-log10/cm2 (P = 0.08) and 0.2-log10/cm2 (P = 0.12) on the skin surface using soaking and spraying approaches, respectively. Aqueous O3 did not cause any significant changes in the drumstick skin color. The Salmonella load of < 4.5-log10/cm2 was a strong predictor for the reduction rate (P < 0.001, R2 = 0.64). These results provide important information that helps the poultry processing facilities for selecting the optimal operational strategy of O3 as an effective antimicrobial.

The utility of Amies charcoal bacteriology swabs for storage of canine urine prior to culture.

To determine the usefulness of bacteriology swabs as a storage method of canine urine samples and the effect on quantitative bacterial culture. Two hundred fourteen canine urine samples were collected by cystocentesis. The reference aliquot was placed in a sterile tube and processed for quantitative bacterial culture within 6hours. A bacteriology swab was then immersed in the urine for 5seconds and returned to the charcoal Amies media container. The urine samples in the sterile tube and bacteriology swab were stored at room temperature for 48 hours and processed for quantitative bacterial culture. Thirty-seven of the samples were positive on reference culture with a total of 42 bacterial isolates. Samples stored in sterile tube and bacteriology swab had identical sensitivity and specificity for detection of bacteriuria (94.7% and 100%, respectively) with very good agreement (κ=0.92; 95% CI 0.81 to 1.00). Agreement between the bacterial species of the reference sample and the bacteriology swab was higher (κ=0.85; 95% CI 0.71 to 0.99) than compared to the sterile tube (κ=0.78; 95% CI 0.62 to 0.94), but the overlapping confidence intervals mean improved agreement cannot be inferred. Bacteriology swabs stored in Amies charcoal transport media should be considered an alternative method to preserve canine urine sample when immediate processing for quantitative bacterial culture is not possible. The sensitivity of culturing plain urine, stored for 48 hours in a sterile tube, for detection of bacteriuria, was higher than previously reported.

S0507 SIBO Diagnosis: Clinical Survey of Practice Patterns, Unmet Needs, and Perception of a Novel Ingestible Diagnostic Capsule

INTRODUCTION: Small intestinal bacterial overgrowth (SIBO) has clinical overlap with irritable bowel syndrome (IBS) and is diagnosed either by endoscopic small bowel aspiration (SBA) with quantitative bacterial culture or hydrogen breath testing (BT). SBA is invasive and lacks standardization and BT has questionable accuracy and unreliable performance. METHODS: Qualitative phone interviews with 7 GIs/3 IBS experts explored unmet needs in SIBO diagnosis and gathered feedback on a novel smart capsule bacterial detection system (SCBDS)—an ingestible capsule with an integrated assay for wirelessly determining small intestinal total bacterial count based on an FDA-approved threshold of ≥105 CFU/ml. A quantitative online survey of 28 academic and 62 community GIs assessed practice patterns and preferred clinical characteristics of SCBDS. RESULTS: GIs saw 77 IBS and 22 SIBO patients on average per month. Suspected SIBO patients (36%) were formally diagnosed by BT with academic GIs placing a greater importance on a formal diagnosis rather than empiric antibiotic therapy. 10% of practices performed SBA for SIBO diagnosis (Figure 1). SIBO diagnosis was evaluated by BT in 47% of patients with only a fraction of GIs giving high ratings for BT accuracy. Empiric antibiotic therapy was performed in ∼50% of suspected SIBO patients across both settings, but 91% were at least somewhat concerned with this practice and 60% were unsatisfied with all current diagnostic options (Figure 2). Insufficient accuracy was the most frequently selected diagnostic unmet need, with 58% of GIs selecting it as one of the greatest unmet needs, followed by difficulty in interpreting results (48%) (Figure 3). Over 70% of GIs indicated that SCBDS would be more accurate than BT and would recommend it to almost two-thirds of patients evaluated for SIBO and to one-third for IBS. Two-thirds of GIs also anticipated using SCBDS first over empiric antibiotic therapy alone. In addition, 59% of BT users and 66% performing SBA would replace these methods with SCBDS. CONCLUSION: GIs in both community and academic settings expressed a significant unmet need in SIBO diagnosis driven by BT performance limitations, and only a small minority of GIs were performing SBA to diagnose SIBO. A perceived strength of an FDA-approved SCBDS would be improved accuracy, interpretation and precision as compared to BT, with the majority of GIs suggesting they would replace conventional SIBO diagnostics with such a technology.Figure 1.: Patient workup for suspected of SIBO vs IBS.Figure 2.: Gastroenterologists satisfaction with currently available options to diagnose SIBO.Figure 3.: Gastroenterologists current perception of unmet medical need for diagnosing SIBO.

Room for Improvement: Results of a Baseline Evaluation of Environmental Cleaning in a Resource-Limited Neonatal Unit

Background: Contamination of the near-patient hospital environment including work surfaces and equipment, contributes to skin colonization and subsequent invasive bacterial infections in hospitalized neonates. In resource-limited settings, cleaning of the neonatal ward environment and equipment is seldom standardized and infrequently audited. Methods: A baseline multimodal assessment of surface and equipment cleaning was performed in a 30-bed high-care neonatal ward in Cape Town, South Africa, October 7–9, 2019. Adequacy of routine cleaning was evaluated using ATP bioluminescence assays, fluorescent ultraviolet (UV) markers, and quantitative bacterial surface cultures. For flat surfaces (eg, tables, incubators, trolleys), a 10×10-cm template was used to standardize the swab inoculum; for small equipment and devices with complex surfaces (eg, humidifiers, suction apparatus, stethoscopes), a standard swabbing protocol was developed for each item. Swabs in liquid transport medium were processed in the laboratory by vortexing for 30 seconds, plating onto blood and MacConkey agars, and incubating at 37°C for 48 hours. Manual counting of bacterial colony forming units was performed, followed by conventional biochemical testing and/or VITEK automated identification. Results: Of 100 swabs (58 from surfaces and 42 from equipment), 11 yielded growth of known neonatal pathogens (Enterobacteriaceae, A. baumannii, P. aeruginosa, S. aureus, S. agalactiae, and enterococci), 36 isolated potential neonatal pathogens (mostly coagulase-negative staphylococci). In addition, 4 grew environmental organisms and 49 showed no growth. The highest aerobic colony counts (ACCs) were obtained from swabs of suction tubing, milk kitchen surfaces, humidifiers, and sinks; the median ACC from swabs with any bacterial growth (n = 51) was 3 (IQR, 1–22). Only 40% of the 100 surface and equipment swabs had ATP values &lt;200 relative light units (RLU) threshold for cleanliness. Median ATP values were 301 (IQ range, 179–732) RLUs for surface swabs versus 230 (IQ range, 78–699) RLUs for equipment swabs (P = .233). Of the 100 fluorescent UV markers placed on near-patient surfaces and high-touch equipment, only 23% had been removed after 2 staff shift changes (24 hours later). Surfaces had a higher proportion of UV marker removal than equipment (19 of 58 [32.8%] vs 4 of 42 [9.5%]; P = .008). Conclusions: Environmental cleaning of this neonatal ward was suboptimal, especially for equipment. Improvement of environmental cleaning practices is an important intervention for neonatal infection prevention in resource-limited settings. Future studies should evaluate the impact of staff training, environmental cleaning tools and repeated audit with feedback, on the adequacy of cleaning in neonatal wards.Funding: Funding: for the laboratory work was provided by The Society for Healthcare Epidemiology of America (SHEA) International Ambassador Alumni Research Award and a South African Medical Research Council Self-initiated Research (SIR) Grant to Angela Dramowski, who is supported by a NIH Fogarty Emerging Global Leader Award K43 TW010682.Disclosures: None

The effect of continuous diffusion of oxygen treatment on cytokines, perfusion, bacterial load, and healing in patients with diabetic foot ulcers

To evaluate continuous diffusion of oxygen therapy (CDO) on cytokines, perfusion, and bacterial load in diabetic foot ulcers we evaluated 23 patients for 3 weeks. Tissues biopsies were obtained at each visit to evaluate cytokines and quantitative bacterial cultures. Perfusion was measured with hyperspectral imaging and transcutaneous oxygen. We used paired T tests to compare continuous variables and independent T tests to compare healers and nonhealers. There was an increase from baseline to week 1 in TGF‐β (P = .008), TNF‐α (P = .014), VEGF (P = .008), PDGF (P = .087), and IGF‐1 (P = .058); baseline to week 2 in TGF‐β (P = .010), VEGF (P = .051), and IL‐6 (P = .031); and baseline to week 3 with TGF‐β (P = .055) and IL‐6 (P = .054). There was a significant increase in transcutaneous oxygen after 1 week of treatment on both medial and lateral foot (P = .086 and .025). Fifty‐three percent of the patients had at least a 50% wound area reduction (healers). At baseline, there were no differences in cytokines between healers and nonhealers. However, there was an increase in CXCL8 after 1 week of treatment (P = .080) and IL‐6 after 3 weeks of treatment in nonhealers (P = .099). There were no differences in quantitative cultures in healers and nonhealers.