Performance evaluation of machine-assisted interpretation of Gram stains from positive blood cultures.

Manual microscopy of Gram stains from positive blood cultures (PBCs) is crucial for diagnosing bloodstream infections but remains labor intensive, time consuming, and subjective. This study aimed to evaluate a scan and analysis system that combines fully automated digital microscopy with deep convolutional neural networks (CNNs) to assist the interpretation of Gram stains from PBCs for routine laboratory use. The CNN was trained to classify images of Gram stains based on staining and morphology into seven different classes: background/false-positive, Gram-positive cocci in clusters (GPCCL), Gram-positive cocci in pairs (GPCP), Gram-positive cocci in chains (GPCC), rod-shaped bacilli (RSB), yeasts, and polymicrobial specimens. A total of 1,555 Gram-stained slides of PBCs were scanned, pre-classified, and reviewed by medical professionals. The results of assisted Gram stain interpretation were compared to those of manual microscopy and cultural species identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The comparison of assisted Gram stain interpretation and manual microscopy yielded positive/negative percent agreement values of 95.8%/98.0% (GPCCL), 87.6%/99.3% (GPCP/GPCC), 97.4%/97.8% (RSB), 83.3%/99.3% (yeasts), and 87.0%/98.5% (negative/false positive). The assisted Gram stain interpretation, when compared to MALDI-TOF MS species identification, also yielded similar results. During the analytical performance study, assisted interpretation showed excellent reproducibility and repeatability. Any microorganism in PBCs should be detectable at the determined limit of detection of 105 CFU/mL. Although the CNN-based interpretation of Gram stains from PBCs is not yet ready for clinical implementation, it has potential for future integration and advancement.

Nocardioides agri sp. nov., isolated from garden soil.

A novel bacterial strain, designated as MAH-18T, was isolated from soil sampled in a flower garden. Cells of strain MAH-18T were Gram-stain-positive, aerobic, motile, and rod-shaped. The colonies were beige in colour, smooth, and spherical when grown on Reasoner's 2A agar medium. Strain MAH-18T grew at 20-40 °C, pH 6.0-8.0, and 0-1.0 % NaCl. Cells were able to hydrolyse aesculin, gelatin, and Tween 20. According to the 16S rRNA gene sequence comparisons, the isolate was determined to be a member of the genus Nocardioides and most closely related to Nocardioides pyridinolyticus OS4T (97.9 %), Nocardioides hankookensis DS-30T (97.9 %), Nocardioides aquiterrae GW-9T (97.6 %), Nocardioides soli mbc-2T (97.5 %), Nocardioides conyzicola HWE 2-02T (97.4 %), and Nocardioides mangrovi GBK3QG-3T (96.3 %). Strain MAH-18T has a draft genome size of 4 788 325 bp (eight contigs), 4572 protein-coding genes, 46 tRNA, and three rRNA genes. The average nucleotide identity and digital DNA-DNA hybridization values between strain MAH-18T and the closest type strains were 81.5-83.4 % and 24.4-25.8 %, respectively. In silico genome mining revealed several biosynthetic gene clusters in the genome of the novel strain MAH-18T. The G+C content of the genomic DNA of strain was 72.2 mol% and the predominant isoprenoid quinone was MK-8 (H4). The main polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and unknown phospholipids. The major cellular fatty acids were determined to be C16:0 iso and C17 : 1 ω6c. The DNA-DNA hybridization results and phenotypic, genotypic, and chemotaxonomic data demonstrated that strain MAH-18T represents a novel species, for which the name Nocardioides agri sp. nov. is proposed, with MAH-18T as the type strain (=KACC 19744T=CGMCC 1.13656T).

The diagnostic accuracy of Gram stain on formalin-fixed paraffin-embedded sections of skin tissue in the diagnosis of bacterial skin infection.

BACKGROUND AND OBJECTIVE: To evaluate the sensitivity, specificity, and likelihood ratios of Gram stain on formalin-fixed, paraffin-embedded (GS-FFPE) sections of skin in diagnosing bacterial skin infection. METHODS: We reviewed a retrospective series of skin specimens reported at our institution wherein histopathological assessment included Gram stain and fresh tissue was concurrently submitted for microscopy and culture. The clinicopathological correlation was the reference standard, whereby the presence of infection was deduced from the final diagnosis in each patient's case notes. RESULTS: Our sample included 168 cases (105 positive for infection). GS-FFPE showed a sensitivity of 0.43 (95% confidence interval 0.29, 0.57), a specificity of 0.98 (0.95, 1.01), a positive likelihood ratio of 21.50 (19.76, 23.24), and a negative likelihood ratio of 0.58 (0.41, 0.75). CONCLUSIONS: GS-FFPE has poor sensitivity, and a negative result should not be used as evidence to exclude infection. In contrast, it has excellent specificity and, unless the pretest probability of infection is very low, a positive result would make infection much more likely. The value of the GS-FFPE lies in cases where sterile tissue was not submitted for microbiological studies, or sterile tissue culture was negative, and there is at least a low-to-moderate pretest probability of infection.

Evaluation of Gram Stain-Guided Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus Pneumonia in Intensive Care Unit Patients.

Background: Despite high negative predictive values (NPVs) seen with methicillin-resistant Staphylococcus aureus (MRSA) nares polymerase chain reaction (PCR) assays, utilization of both respiratory sample Gram stain and MRSA nares PCR in patients with pneumonia may contribute to overuse of laboratory resources. The purpose of this study was to evaluate if a Gram stain demonstrating no Gram-positive organisms from a respiratory sample is sufficient to allow for de-escalation of vancomycin therapy. Methods: This single center study retrospectively identified intensive care unit (ICU) patients started on vancomycin for presumed pneumonia at University of Wisconsin (UW) Health in Madison, WI between August 2022 and March 2023. Patients with respiratory sample demonstrating no Gram-positives on Gram stain met inclusion criteria if the sample was ordered within 24 h of vancomycin initiation. The primary outcome was NPV of respiratory sample Gram stain demonstrating no Gram-positive organisms with respect to MRSA detection of the respiratory culture. Secondary outcomes included the NPV of combined MRSA nares PCR plus respiratory sample Gram stain, and difference in time to event in patients that had both a respiratory sample and MRSA nares PCR ordered. Results: A total of 370 patients were screened for study eligibility; of which 99 patients met inclusion criteria. NPV of respiratory sample Gram stain was 99% for MRSA culture. The combined NPV of respiratory sample Gram stain plus MRSA nares PCR was 98.9% for MRSA culture (n = 88). Respiratory sample was ordered 2.3 h faster compared to MRSA nares PCR (4.3 vs 6.6 h, P = .036). Respiratory sample Gram stain resulted 4.5 h faster compared to MRSA nares PCR (10.7 vs 15.2 h, P = .002). Conclusion: Respiratory sample Gram stains demonstrating no Gram-positive organisms may be used to de-escalate vancomycin and deprioritize the use of MRSA nares PCR.

Reviving Sternheimer stain: A single-center retrospective study to detect the diagnostic utility of urinary tract infections in the emergency department.

INTRODUCTION: Qualitative urinalysis using the Sternheimer stain is a common method in Japan for identifying bacteriuria, but there is a lack of studies examining its test characteristics. In this study, we aimed to investigate the sensitivity and specificity of the Sternheimer stain for urine culture results and compare it with the sensitivity and specificity of the Gram stain. Our goal was to determine the usefulness of the Sternheimer stain in identifying bacteriuria. PATIENTS AND METHODS: Among 986 patients aged 16 years or older from whom samples for both urinalysis and urine culture were obtained at the emergency room of Tenri Hospital from January 2019 to December 2019, 342 patients with pyuria, defined as the presence of 10 or more white cells per cubic millimeter in a urine specimen, who had not received prior antimicrobial therapy were included. Urine cultures were used for comparison to determine the sensitivity and specificity of Sternheimer and Gram stain in this patient group. A positive Sternheimer stain result was defined as bacteriuria ≥ (1+), and that of Gram stain was defined as ≥ 1/1 field of high-power ( × 1000) oil immersion. RESULTS: Using urine culture results for comparison, the sensitivity of Sternheimer stain was 92.2%, the specificity was 48.5%, the positive likelihood ratio was 1.79, and the negative likelihood ratio was 0.16. DISCUSSION: Sternheimer stain is a rapid and useful method to exclude bacteriuria in a group of patients with pyuria in the emergency department.

Q-Scoring System for the Evaluation of the Superficial Wound Swab Samples: A Clinical Microbiological Aspect.

Purpose: Wound swab cultures are frequently requested from patients suspected of having a wound infection. The quality of the sample should also be evaluated by performing a Gram-stained microscopic examination. "Q-scoring system" is not widely used and the literature on the subject is limited. Methods: A total of 4648 wound swab samples were evaluated. Samples with a Q-score of "0" were considered as "poor quality samples", and those with a score of " ≥ 1" were classified as "good quality samples". Microorganisms grown in the culture of samples that scored above one were identified by mass spectrometry, and antimicrobial susceptibility testing was performed. Results: Gram stain results were found to be consistent with the culture result in 57.10% (n = 1078) of and inconsistent with the culture result in 42.90% (n = 813) of the samples. The number of samples with Q-scores one, two, and three among the 813 samples was 62, 29, and 722, respectively. The value observed in Q3 was found to be statistically significantly higher than the values observed in Q1 and Q2 (p < 0.05). Samples sent from surgical departments (61.92%) with a Q-score of ≥ 1, were statistically significant compared to internal medicine departments (p < 0.0001). There was no significant difference between samples sent from intensive care units and those sent from other inpatient services. For both groups with Q-scores ≥ 1 and "0" similar microorganisms were identified. Conclusion: As a conclusion, the Q-scoring system will provide a common language between the laboratory and the clinic, especially by standardizing the evaluation of wound swab samples.

Is it meaningful to apply midstream urine culture to urine specimens with negative Gram stain results?

INTRODUCTION: Gram staining is a convenient method for bacterial estimation. Urine culture is typically used to diagnose urinary tract infections. Therefore, urine culture is also performed on Gram stain-negative urine specimens. However, the frequency of uropathogen identification in these samples remains unclear. METHODS: From 2016 to 2019, we retrospectively compared the results of Gram staining and urine culture tests on midstream urine specimens submitted for the diagnosis of urinary tract infections to confirm the significance of urine culture on Gram stain-negative specimens. Analysis was performed according to the patients' sex and age, and the frequency of uropathogen identification in the culture was examined. RESULTS: A total of 1763 urine specimens (women, 931; men, 832) were collected. Of these, 448 (25.4%) were not positive on Gram staining but were positive on culture. In specimens without bacteria on Gram staining, the frequencies of specimens with uropathogens detected on culture were 20.8% (22/106) in women aged <50 years, 21.4% (71/332) in women aged ≥50 years, 2.0% (2/99) in men aged <50 years, and 7.8% (39/499) in men aged ≥50 years. CONCLUSIONS: In men aged <50 years, the frequency of uropathogenic bacteria identification by urine culture was low in Gram stain-negative specimens. Therefore, urine cultures may be excluded from this group. In contrast, in women, a small number of Gram stain-negative specimens showed significant culture results for the diagnosis of urinary tract infection. Therefore, urine culture should not be omitted in women without careful consideration.

Agriterribacter soli sp. nov., isolated from herbicide-contaminated soil.

A Gram-stain-negative, non-spore-forming and rod-shaped bacterium, designated strain NS-102T, was isolated from herbicide-contaminated soil sampled in Nanjing, PR China, and its taxonomic status was investigated by a polyphasic approach. Cell growth of strain NS-102T occurred at 16-42 °C (optimum, 30 °C), at pH 5.0-8.0 (optimum, pH 6.0) and in the presence of 0-3.5 % (w/v) NaCl (optimum, without addition of NaCl). The 16S rRNA gene sequence of strain NS-102T shows high similarity to that of Agriterribacter humi YJ03T (96.9 % similarity), followed by Terrimonas terrae T16R-129T (93.8 %) and Terrimonas pekingensis QHT (93.6 %). Average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between the draft genomes of strain NS-102T and A. humi YJ03T were 72.5, 69.4 and 18.6%, respectively. The only respiratory quinone was MK-7, and phosphatidylethanolamine and unidentified lipids were the major polar lipids. The major cellular fatty acids of strain NS-102T contained high amounts of iso-C15 : 0 (24.6 %), iso-C17 : 03-OH (24.1 %), iso-C15 : 0 G (16.6 %) and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) (15.6 %). The G+C content of the total DNA was determined to be 40.0 mol%. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain NS-102T represents a novel species of the genus Agriterribacter, for which the name Agriterribacter soli sp. nov. is proposed. The type strain is NS-102T (=CCTCC AB 2017249T=KCTC 62322T).

A case of recurrent acute cholecystitis caused by Actinomyces odontolyticus, rare actinomycosis.

BACKGROUNDS: Actinomyces species are gram-positive, obligate anaerobic rods and are rare causes of cholecystitis. Because Actinomyces species are anaerobic bacteria, it is difficult for Actinomyces to survive in bile apart from A. naeslundii. We experienced a case of recurrent acute cholecystitis caused by A. odontolyticus. CASE PRESENTATION: A patient had been diagnosed with acute cholecystitis and treated one month before and after that, admitted to our hospital because of recurrent cholecystitis. Gram stain of the bile revealed gram-positive rods and gram-positive cocci. We found A. odontolyticus and MRSA in bile culture and MRSA in blood culture. We administered piperacillin-tazobactam and then changed it to ampicillin-sulbactam and vancomycin. The patient underwent laparoscopic cholecystectomy and was discharged safely. CONCLUSIONS: To our knowledge, this is the first case of cholecystitis caused by A. odontolyticus. Cholecystitis caused by Actinomyces species is rare. In addition, we may overlook it with the low positivity of bile cultures of Actinomyces. Whenever the cholecystitis recurs without any obstruction of the biliary tract, we should search for the gram-positive rods hidden in the bile, such as A. odontolyticus, as the causative organism, even if the bile culture is negative.

Point-of-care urine Gram stain led to narrower-spectrum antimicrobial selection for febrile urinary tract infection in adolescents and adults.

BACKGROUND: Febrile urinary tract infections (fUTIs), which include pyelonephritis, prostatitis, and urosepsis, are the most common cause of sepsis. However, the treatment has become more complex because of the worldwide increase in antimicrobial resistance (AMR). The objective of this study was to clarify whether point-of-care Gram stain (PCGS) of urine contributed to fUTI diagnosis and treatment in adults. METHODS: This hospital-based observational study was undertaken between January 2013 and March 2015 in Okinawa, Japan. All enrolled patients were adults who had been admitted to the Division of Infectious Diseases with suspected fUTI. The usefulness of PCGS results were compared for urinalysis (U/A) and urine cultures (U/Cs). The targeted therapy type and its susceptibility based on PCGS were analyzed, and each was investigated in two groups: the uncomplicated pyelonephritis group and the complicated pyelonephritis/prostatitis group. RESULTS: Two hundred and sixty-six patients were enrolled. The results of PCGS were closely correlated with those of U/A for pyuria and bacteriuria, and moderately correlated with the results of U/C for bacterial types. In the uncomplicated group, narrow-spectrum antimicrobials such as cefotiam were initially selected in 97.9% (47/48) of patients, and their susceptibility was 97.9% (47/48). In the complicated group, the susceptibility was 84.2% (186/221) (p = 0.009) despite frequent AMRs (14.7%; 32/218) and low use of broad-spectrum antimicrobials such as carbapenems (7.7%; 17/221). CONCLUSION: Urine PCGS led to a more precise fUTI diagnosis and prompted clinicians to select narrower-spectrum antibiotics with high susceptibility.

The 24-h reporting of Gram stains from positive blood cultures contributes to physician's use of appropriate antimicrobials: Experience at a university hospital.

Although recent technological advances for the diagnosis of bloodstream infection (BSI) provide rapid and accurate results, blood culture maintains a key role in the diagnosis of BSI. The objective of this study was to determine whether 24-h reporting by telephone to disclose the suspected microorganism based on the Gram stain morphology from positive blood cultures (first laboratory report) affects a physician's use of appropriate antimicrobials. A total of 627 (14%) out of 4413 blood samples, excluding duplicate samples from the same patient on the same day, were positive for blood cultures between January and December 2016. The contamination rate of blood cultures during the study period was 2.3%. Among 627 patients with positive blood cultures, 538 (86%) were receiving antibiotics at the time of the first laboratory report, of which 502 (80%) thereafter continued the same antimicrobials, and the remaining 36 (6%) were changed to appropriate antimicrobials after the first laboratory report. An additional 25 (4%) were newly administered appropriate antimicrobials after the first laboratory report, whereas an additional 21 (3%) were newly administered appropriate antimicrobials after infection control team (ICT)-intervention. The median time lag (interquartile ranges) from flagging culture bottles as positive to a physician's use of appropriate antimicrobials after the first laboratory report (4 h, 2-7) was significantly (p < 0.001) shorter than that after ICT-intervention (12 h, 10-17). During the study period, no cases of discrepancy between the Gram stain morphology in the first laboratory report and definitive identification of microorganisms in the final laboratory report were observed. Because the timing of flagging culture bottles as positive tends to fall outside normal working hours, immediate 24-h reporting by telephone to disclose the suspected microorganism based on the Gram stain morphology from positive blood cultures may contribute to an early recognition of bacteremia and the physician's use of appropriate antimicrobials.

Value of sputum Gram stain, sputum culture, and bronchoalveolar lavage fluid Gram stain in predicting single bacterial pathogen among children with community-acquired pneumonia.

BACKGROUND: Currently, the microbial etiology of community-acquired pneumonia in children remains challenging. While Gram stain and sputum culture are commonly used to detect bacterial pathogens, it is unclear whether these approaches can predict single pathogen from bronchoalveolar lavage fluid (BALF) culture. METHODS: A retrospective study involving 287 children hospitalized for pneumonia was conducted. Sputum specimens were collected on admission; and BALF specimens were collected within 24 h after admission. Taking BALF culture as the reference standard, the sensitivity and specificity of Sputum Gram stain (SGS), sputum culture, and BALF Gram stain (BGS) were calculated. The agreement between these approaches and BALF culture was compared using kappa statistics. RESULTS: For SGS, the specificity was 23%. The overall sensitivity was 70%, including 87% for Gram-positive (G+) cocci, 56% for Gram-negative (G-) cocci, and 50% for G-bacilli. For sputum culture, the specificity was 70%. The overall sensitivity was 64%, including 71% for Streptococcus pneumoniae, 71% for Moraxella catarrhalis, and 64% for Haemophilus influenzae. For BGS, the specificity was 71%. The overall sensitivity was 60%, including 77% for G+cocci, 38% for G-cocci, and 44% for G-bacilli. While SGS had poor agreement with BALF culture, both sputum culture and BGS had moderate agreement with BALF culture. CONCLUSIONS: Both sputum culture and BGS are helpful in predicting single bacterial pathogen from BALF culture among children with community-acquired pneumonia. Sputum cultures and BGS can provide early clues for BALF pathogen when BALF culture results are pending or bronchoscopy is not performed.

Fc-MBL-modified Fe3O4 magnetic bead enrichment and fixation in Gram stain for rapid detection of low-concentration bacteria.

Functional bacterial enrichment magnetic beads (Fe3O4@SiO2@Fc-MBL) and Gram staining were combined for the fast diagnosis of infecting bacteria in meningitis. Fe3O4@SiO2@Fc-MBL has excellent microbial binding ability and can be used for bacterial enrichment from cerebrospinal fluid (CSF). The enriched bacteria are recognized by Gram stain at very low concentrations (10 CFU·mL-1). The feasibility of this method was verified by five common bacteria in meningitis infection (Gram-positive: Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus capitis; Gram-negative: Klebsiella pneumoniae and Escherichia coli). The extraction efficiency of Fc-MBL-modified Fe3O4 magnetic beads was approximately 90% in artificial CSF for the selected bacteria, with the exception of E. coli (~ 60%). The bacteria were successfully recognized by Gram staining and microscopic observation. Fe3O4@SiO2@Fc-MBL acts by capturing and fixing the bacteria in a magnetic field throughout the experiment. Compared with traditional CSF Gram staining, this new method avoids interference by inflammatory cells and red blood cells during microscopic examination. Furthermore, the sensitivity of this method is much better than the centrifugation smear method. The whole process can be accomplished within 30 min. This novel method may have potential as a clinical tool for analysis of bacteria in the CSF.

Gram stain and addition of amphotericin B to improve the microbial safety of human donor corneas.

To determine the effectiveness of two methods to improve the microbial safety of human corneas preserved in organ culture. We compared the number of positive preservation solutions of corneas in organ culture in which the initial short-term hypothermic corneal maintenance solution was supplemented with amphotericin B 2.5 µg/mL and the historical data of microbial test results (2015-2019). In addition, we appraised the efficacy of Gram stain to detect bacterial or fungal contamination in the organ culture solutions of corneas from at-risk donors compared to the culture tests of corneas from not-at-risk donors. Statistical analysis was performed using STATA and statistical significance set at p < 0.05. The number of positive culture tests after preservation was 15 (0.5%) in 2020 compared to a mean of 37 (1.2%) in the period 2015-2019 (p < 0.01), with 10 (1.0%) positive samples in the cohort of 998 corneas from at-risk donors and 5 (0.2%) in the 2046 corneas from not-at-risk donors (p < 0.01). All corneas from at-risk donors tested positive at Gram stain and the results were available 1-3 days before those of the conventional culture tests. Amphotericin B supplementation in the short-term maintenance solution markedly reduced the number of positive microbial tests after organ culture and the early detection of contaminants, including slow-growing microorganisms, by Gram stain before the standard culture results. This meant fewer corneas being discarded and a greater likelihood of preventing post-graft infections.

Development of a Machine learning image segmentation-based algorithm for the determination of the adequacy of Gram-stained sputum smear images.

Background: Machine learning (ML) prepares and trains a model through supervised or unsupervised learning methods. Sputum, a respiratory tract secretion, is a common laboratory specimen that aids in diagnosing respiratory diseases, including pulmonary tuberculosis (TB). Gram stain is an easy, cost-effective stain, which may be applied to sputum smears to screen out an unsatisfactory sample. ML model may help in screening sputum smears. Methods: This collaborative project was carried out from June 2020-July 2021. In this study, a color-based segmentation ML algorithm using K-Means clustering was developed. A library of stained sputum smears was built. The Bartletts criteria (based on neutrophil and squamous cell count) for screening and selecting satisfactory sputum smears were used. A smartphone camera was used to take several photographs of satisfactory, as well as unsatisfactory, smears. The image segmentation algorithm was applied to medical image analysis, color-segmentation of sputum images was done. The hue saturation value (HSV) color ranges were defined on a prototype image. Then, all connected pixels were identified as a single object, and morphological operations were applied. Results: Usage of AI-driven model on the slide-image revealed the slide adequacy as the cell count was acceptable based on Bartlett's criteria. Both the manual cell counts (Range: 126-203 neutrophils, 14-47 squamous cells) and the model counts (Range: 117-242 neutrophils, 14-37 squamous cells) are within acceptable limits. Conclusion: The use of a model to screen a large number of sputum slides may be a boon in resource-limited settings where trained microscopists may not be easily available.

Renal pelvis urine Gram stain as a traditional, but new marker in predicting postoperative fever and stone culture positivity in percutaneous nephrolithotomy: an observational, prospective, non-randomized cohort study.

PURPOSE: The aim of this study was to evaluate the diagnostic value of renal pelvis urine Gram staining (RPUGS) in predicting postoperative fever and renal stone culture (RSC) positivity in percutaneous nephrolithotomy (PCNL). METHODS: Totally 141 consecutive patients undergoing PCNL for renal stone were included between January 2018 and December 2019. The RPUGS and renal pelvis urine culture (RPUC) were performed using urine sample from renal collecting system, while RSC was performed using stone fragments. Patients were divided into two groups as Group 1 (n = 119) without postoperative fever (< 38 °C) and Group 2 (n = 22) with postoperative fever (≥ 38 °C). Stone culture and Gram staining models were created for predicting postoperative fever using constant covariates of the presence of residual stone, hydronephrosis, and stone burden. RESULTS: A significantly higher number of patients in Group 2 had RPUGS, RSC, and RPUC positivity (p < 0.001, for each). The sensitivity, specificity, positive predictive value, and negative predictive value of RPUGS in predicting postoperative fever were 72.7%, 89.9%, 57.1%, and 94.7%, respectively. It was observed that both models had similar predictive values and diagnostic performances. Although RSC and RPUGS had a similar diagnostic value in predicting postoperative fever in univariable analysis, both were found to be independent predictors in multivariable analysis (OR: 10.6, 95% CI 4.07-27.9, p < 0.001 and OR: 15.0, 95% CI 5.4-41.2, p < 0.001, respectively). CONCLUSIONS: In conclusion, RPUGS is as effective as RSC in predicting fever after PCNL. We recommend RPUGS during PCNL to manage post-PCNL infectious complications.

Xanthobacter dioxanivorans sp. nov., a 1,4-dioxane-degrading bacterium.

A Gram-stain-negative bacterium, designated as YN2T, that is capable of degrading 1,4-dioxane, was isolated from active sludge collected from a wastewater treatment plant in Harbin, PR China. Cells of strain YN2T were aerobic, motile, pleomorphic rods, mostly twisted, and contained the water-insoluble yellow zeaxanthin dirhamnoside. Strain YN2T grew at 10-40 °C (optimum, 30 °C), pH 5.0-8.0 (pH 7.0) and with 0-1 % (w/v) NaCl (0.1 %). It also could grow chemolithoautotrophically and fix N2 when no ammonium or nitrate was supplied. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YN2T belongs to the genus Xanthobacter and shares the highest pairwise identity with Xanthobacter autotrophicus 7cT (98.6 %) and Xanthobacter flavus 301T (98.4 %). The major respiratory quinone was ubiquinone-10. Chemotaxonomic analysis revealed that the strain possesses C16 : 0, C19 : 0 cyclo ω8c and C18 : 1 ω7c as the major fatty acids. The DNA G+C content was 67.95 mol%. Based on genome sequences, the DNA-DNA hybridization estimate values between strain YN2T and X. autotrophicus 7cT, X. flavus 301T and X. tagetidis TagT2CT (the only three species of Xanthobacter with currently available genomes) were 31.70, 31.30 and 28.50 %; average nucleotide identity values were 85.23, 84.84 and 83.59 %; average amino acid identity values were 81.24, 80.23 and 73.57 %. Based on its phylogenetic, phenotypic, and physiological characteristics, strain YN2T is considered to represent a novel species of the genus Xanthobacter, for which the name Xanthobacter dioxanivorans sp. nov. is proposed. The type strain is YN2T (=CGMCC 1.19031T=JCM 34666T).

Performances of automated digital imaging of Gram-stained slides with on-screen reading against manual microscopy.

The objective of this study was to evaluate the performances of the automated digital imaging of Gram-stained slides against manual microscopy. Four hundred forty-three identified Gram-stained slides were included in this study. When both methods agreed, we considered the results as correct, and no further examination was carried out. Whenever the methods gave discrepant results, we reviewed the digital images and the glass slides by manual microscopy to avoid incorrectly read smears. The final result was a consensus of multiple independent reader interpretations. Among the 443 slides analyzed in this study, 101 (22.8%) showed discrepant results between the compared methods. The rates of discrepant results according to the specimen types were 5.7% (9/157) for positive blood cultures, 42% (60/142) for respiratory tract specimens, and 22% (32/144) for sterile site specimens. After a subsequent review of the discrepant slides, the final rate of discrepancies dropped to 7.0% (31/443). The overall agreement between the compared methods and the culture results reached 78% (345/443) and 79% (349/443) for manual microscopy and automated digital imaging, respectively. According to culture results, the specificity for automated digital imaging and manual microscopy were 90.8% and 87.7% respectively. In contrast, sensitivity was 84.1% for the two compared methods. The discrepant results were mostly encountered with microorganism morphologies of rare occurrence. The results reported in this study emphasize that on-screen reading is challenging, since the recognition of morphologies on-screen can appear different as compared to routine manual microscopy. Monitoring of Gram stain errors, which is facilitated by automated digital imaging, remains crucial for the quality control of reported Gram stain results.

The Significance of Age and Causative Bacterial Morphology in the Choice of an Antimicrobial Agent to Treat Acute Uncomplicated Cystitis.

Differentiating patients by age and causative bacterial morphology might aid in making the appropriate choice of antimicrobial agent when treating acute uncomplicated cystitis. In this retrospective analysis, the non-susceptibility rates of the causative bacteria to cefcapene-pivoxil (CFPN-PI) and levofloxacin (LVFX) were determined after dividing patients with acute uncomplicated cystitis by age group (15-54 and 55-74 years old) and by bacterial morphology: gram-positive cocci (GPC) or gram-negative rod (GNR). The overall non-susceptibility rates for CFPN-PI and LVFX were 19.4% and 15.3%, respectively. When the subjects were divided by age, only the non-susceptibility rate for LVFX in the younger group significantly decreased (to 8.7%). When the groups were divided by both age and bacterial morphology, the younger GNR group had non-susceptibility rates of 6.9% to CFPN-PI and 7.8% to LVFX, whereas the younger GPC group showed 10.2% non-susceptibility to LVFX. The older GNR group showed 9.8% non-susceptibility to CFPN-PI, while the older GPC group showed 7.2% non-susceptibility to LVFX. All the non-susceptibility rates were lower than 10.2% in the sub-divided groups. Differentiating patients by age and the morphology of causative bacteria can aid in making the appropriate choice of antimicrobial agent and may improve treatment outcomes in patients with acute uncomplicated cystitis.

The use of vaginal wet smear: can we predict Mycoplasmas/Ureaplasmas?

PURPOSE: To evaluate the agreement of wet smear microscopy with Gram stain microscopy and to assess whether it is possible to predict Mycoplasmas/Ureaplasmas when analysing vaginal secretion with Gram stain and wet smear microscopy. METHODS: Women with complaints of the abnormal vaginal discharge were invited to participate. A sample of vaginal secretion was taken for wet smear microscopy and for Gram staining analysis. A sample from the endocervical canal was taken for DNA detection of seven infections: Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma parvum, Ureaplasma urealyticum, Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis. The percentage agreement between wet smear and Gram stain was determined and the Cohen's Kappa values were calculated. RESULTS: Of 158 consecutive women included, one (or a few) of the infections were detected in 54% of them and the most frequent infection was Ureaplasma parvum (79% of all the cases with infections). The percentage agreement between vaginal wet smear and Gram stain was 73% (Cohen's Kappa value 0.63). A statistically significant association between the DNA detected Mycoplasmas/Ureaplasmas and bacterial vaginosis was found (positive amine test p = 0.046, wet smear p = 0.005 and Gram stain p = 0.03). CONCLUSIONS: There was a statistically significant association between bacterial vaginosis and the DNA detected Mycoplasmas/Ureaplasmas. The agreement of vaginal wet smear with Gram stain was good.