Clinical Microbiological Culture Research Articles

Semi-quantitative analysis with 99mTc-Besilesomab in musculoskeletal system infections

ObjectivesTo evaluate the usefulness of 99mTc-Besilesomab to diagnose infectious processes by using monoclonal antibodies BW 250/183 in a semi-quantitative analysis, and to determine the effect on diagnostic capacity of different thresholds for the difference between counts in early versus delayed images. MethodsThe study included 77 patients with suspected osteomyelitis who underwent scintigraphy with 99mTc-Besilesomab. After confirming the absence of human anti-mouse antibodies in all patients, early and delayed static images were acquired at 4 and 24 h post-injection, respectively. Visual and semi-quantitative analyses were conducted of regions of interest (ROIs) in areas suspected of infection on early and delayed images. Findings were considered positive when the ratio between counts in delayed and early images exceeded a given threshold after correction for decay. The definitive diagnosis was obtained by clinical follow-up, microbiological culture, or response to medical and/or surgical treatment. ResultsThe optimal threshold was 1.02 (i.e., positive result = count increase of >2 % in delayed image), obtaining a sensitivity of 0.864, specificity of 0.858, positive predictive value of 0.708, negative predictive value of 0.940, and accuracy of 0.860. Application of the usual threshold of 1.10 (10 %) reduced the sensitivity to 0.734. ConclusionSemi-quantitative analysis of studies with 99mTc-Besilesomab is a useful technique for the diagnosis of musculoskeletal system infections and contributes to the definitive diagnosis when visual assessments are doubtful or non-conclusive.

Deep mycosis mimicking cutaneous squamous cell carcinoma.

Deep cutaneous mycoses (DCMs) and skin fungal infections can cause significant morbidity until diagnosed and treated. In immunocompromised people, Candida spp., Aspergillus spp., and Fusarium spp. fungi can cause these infections, but dermatophytes, especially Trichophyton rubrum and T. mentagrophytes, are the most common. Superficial erythematous lesions become firm subcutaneous nodules, ulcers, abscesses, or sinus tracts. In advanced cases, DCMs can cause osteomyelitis and bone loss. DCM included mycetoma, a chronic infectious disease of the skin, subcutaneous tissues, and bones. In some areas, it is endemic and can mimic cutaneous tuberculosis or cancerous lesions, making diagnosis difficult. Clinical presentation, radiological findings, and microbiological culture are used to diagnose with molecular methods helping in culture-negative cases. An immunocompetent farmer with a wrist lesion initially suspected as cutaneous squamous cell carcinoma was histologically diagnosed as eumycetoma, emphasizing the importance of considering deep mycoses in high-risk individuals and their heterogeneous clinical presentation.

Characterization of cerebrospinal fluid (CSF) microbiota at the time of initial surgical intervention for children with hydrocephalus.

To characterize the microbiota of the cerebrospinal fluid (CSF) from children with hydrocephalus at the time of initial surgical intervention. CSF was obtained at initial surgical intervention. One aliquot was stored in skim milk-tryptone-glucose-glycerol (STGG) medium and the second was unprocessed; both were then stored at -70°C. Bacterial growth for CSF samples stored in STGG were subsequently characterized using aerobic and anaerobic culture on blood agar and MALDI-TOF sequencing. All unprocessed CSF samples underwent 16S quantitative polymerase chain reaction (qPCR) sequencing, and a subset underwent standard clinical microbiological culture. CSF with culture growth (either after storage in STGG or standard clinical) were further analyzed using whole-genome amplification sequencing (WGAS). 11/66 (17%) samples stored in STGG and 1/36 (3%) that underwent standard clinical microbiological culture demonstrated bacterial growth. Of the organisms present, 8 were common skin flora and 4 were potential pathogens; only 1 was also qPCR positive. WGAS findings and STGG culture findings were concordant for only 1 sample, identifying Staphylococcus epidermidis. No significant difference in time to second surgical intervention was observed between the STGG culture-positive and negative groups. Using high sensitivity methods, we detected the presence of bacteria in a subset of CSF samples at the time of first surgery. Therefore, the true presence of bacteria in CSF of children with hydrocephalus cannot be ruled out, though our findings may suggest these bacteria are contaminants or false positives of the detection methods. Regardless of origin, the detection of microbiota in the CSF of these children may not have any clinical significance.

Elevated Rates of Ventilator-Associated Pneumonia and COVID-19 Associated Pulmonary Aspergillosis in Critically Ill Patients with SARS-CoV2 Infection in the Second Wave: A Retrospective Chart Review.

Due to multiple risk factors, the rate of ventilator-associated pneumonia in critically ill COVID-19 patients has been reported in a range of 7.6% to 86%. The rate of invasive pulmonary aspergillosis in this cohort has been reported at 4% to 30%. We undertook a retrospective chart review of 276 patients who were admitted to intensive care in a large university hospital. The period studied included patients from 23 February 2014 to 12 May 2021. Four groups were collected: COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia. Clinical characteristics, outcomes, and microbiological cultures were recorded. The incidence of ventilator-associated pneumonia in COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia was 5.45%, 27.40%, 16.67%, and 3.41%, respectively (p < 0.001). The rate of invasive pulmonary aspergillosis was 0%, 9.59%, 13.33%, and 6.82%, respectively (p < 0.001). A significantly elevated rate of ventilator-associated pneumonia and invasive pulmonary aspergillosis was noted in the second wave of COVID-19 when compared to the first. This was accompanied by an increase in the mortality rate. Increased steroid use was an independent risk factor for ventilator-associated pneumonia and invasive pulmonary aspergillosis across all four groups. Despite an increased understanding of this disease, no clinical trials have shown any promising therapeutic options at present.

Is Previous Postoperative Infection an Independent Risk Factor for Postoperative Infection after Second Unrelated Abdominal Operation?

Infections after abdominal surgery remain a significant problem. Although preoperative antibiotic prophylaxis is a primary strategy used to reduce postoperative infections, it is typically prescribed based on standardized protocols, without attention to previous infection or antibiotic history. Patients with a previous infection after surgery may be at higher risk for infectious complications after subsequent operations owing to antibiotic resistance. We hypothesized that a previous postoperative infection is a significant risk factor for the development of infection after a second unrelated surgery. We performed a retrospective study of patients who had undergone 2 unrelated abdominal operations at a tertiary care center from 2012 to 2018. Clinical variables and microbiological culture results were abstracted. Univariate and multivariable regression models were constructed. Of 758 patients, 15.0% (n = 114) developed an infection after the first operation. After the second operation, 22.8% (n = 26) of those with a previous infection developed another infection, whereas the incidence of an infection after the second operation was only 9.5% (n = 61) in patients who did not develop an infection after the first operation. Multivariable analysis demonstrated that previous infection (odds ratio 2.49, 95% CI 1.46 to 4.25) was associated with future infection risk. Microbiological analysis found that infections after the second surgery were significantly more likely to be antibiotic resistant than infections after the first surgery (82.3% vs 64.1%; p = 0.036). Strikingly, 49% of infections after the second surgery were resistant to the antibiotic prophylaxis given at the time of incision. Previous postoperative infection is an independent risk factor for a subsequent postoperative infection and is associated with resistance to standard prophylaxis. Individualization of antibiotic prophylaxis in patients with a previous postoperative infection is warranted.

Detection of mecA and 16S rRNA Genes Using Real-Time PCR Can Be Useful in Diagnosing Iliopsoas Abscess, Especially in Culture-Negative Cases: RT-PCR for Iliopsoas Abscess.

The rapid detection of etiological agents is important for the successful treatment of iliopsoas abscess (IPA). The purpose of this study was to investigate the clinical utility of a real-time polymerase chain reaction (PCR) that targets the mecA gene for methicillin-resistant staphylococci (MRS) and the 16S rRNA gene for pan-bacteria. Our retrospective diagnostic study included 22 patients exhibiting IPAs and four patients with noninfectious iliopsoas mass regions who underwent computerized tomography or ultrasonography-guided biopsy and/or surgical treatment. Clinical symptoms, serum data, imaging analysis, and tissue microbiological culture were utilized for the diagnosis of IPA. The diagnostic accuracy of real-time PCR was determined based on the diagnosis of IPA and microbiological culture results. The microbiological culture was positive for 12 IPA cases that included 2 MRSA infections. Among 12 culture-positive IPA cases, 16S rRNA-PCR was positive in 12 and MRS-PCR in two. Among 10 culture-negative IPA cases, including 3 TB cases, 16S rRNA-PCR was positive in 8 and MRS-PCR in 2. In noninfectious iliopsoas mass patients, neither 16S rRNA nor MRS-PCR detected bacterial DNA. The sensitivity, specificity, positive predictive, and negative predictive values of 16S rRNA-PCR for diagnosing IPA were 0.91, 1.00, 1.00, and 0.67, respectively, while those for the diagnosis of MRS infection with MRS-PCR were 1.00, 0.92, 1.00, and 0.50, respectively. Real-time PCR targeting bacterial DNA can detect bacterial DNA in culture-negative cases and offer improved detectability of MRS infection in IPA patients.

Abstract 11119: Real-Time Nanopore Sequencing for Bacterial Pneumonia After Out-of-Hospital Cardiac Arrest, a Pilot Proof-of-Concept Study

Introduction: Pneumonia is common after OHCA but is difficult to diagnose in the first 72 hours following ROSC, this results in early untargeted antibiotic administration based on non-specific imaging and laboratory findings. Antibiotic resistance is rising, is influenced by untargeted antibiotic administration, and can increase patient morbidity and mortality as well as healthcare costs. Precision methods of bacterial pathogen detection in OHCA patients are needed to improve patient care. This proof-of-concept pilot study aimed to assess feasibility of bacterial pathogen sequencing and comparability of sequencing results to clinical culture after OHCA. Methods: Blood and bronchoalveolar lavage (BAL) were obtained from residual clinical specimens collected within 12 hours of ROSC. Bacterial DNA was extracted using the Qiagen PowerLyzer PowerSoil DNA kit, sequenced using the MinION nanopore sequencer, and analyzed with Oxford Nanopore Technologies’ EPI2ME bioinformatics software. Sequencing results were compared to culture results using McNemar’s chi-square statistic. Study-defined pneumonia was based on presence of at least two characteristics within 72 hours of ROSC: fever (temperature ≥38°C); persistent leukocytosis &gt;15,000 or leukopenia &lt;3,500 for 48 hours; persistent chest radiography infiltrates for 48 hours per clinical radiology read; bacterial pathogen cultured. Results: We enrolled 38 consecutive OHCA subjects: mean age 61.8 years (18.0); 16 (42%) female; 25 (66%) White, 7 (18%) Black, 6 (16%) “Other” race; 7 subjects (18%) survived and 31 (82%) died; 16 (42%) subjects had pneumonia. Sequencing results were available in 12 hours while culture results were available in 48-72 hours after collection. There was a non-significant difference in the proportion of the same pathogens identified for each method per McNemar’s chi-square: p = 0.38, difference of 0.095 (-0.095, 0.286). Conclusions: Nanopore sequencing detects pathogenic bacteria comparable to clinical microbiologic culture and in less time. This technology can produce a paradigm shift in early bacterial pathogen detection in OHCA survivors, which can improve patient care. The technology is applicable to other patient populations and for viral and fungal pathogens.

Differentiating between active and latent tuberculosis with chest computed tomography

PurposeThe purpose of this study was to evaluate the capabilities of chest computed tomography (CT) in distinguishing between active and latent tuberculosis in patients positive for interferon-gamma release assay (IGRA) testing, and to compare the performance of CT with that of quantitative IGRA testing in a low incidence setting. Materials and methodsPatients with latent or active tuberculosis define by an IGRA positive test were retrospectively recruited. Sensitivity, specificity and accuracy were determined for CT variables and quantitative IGRA results. Final diagnosis of active tuberculosis was based on clinical data and microbiological culture. Univariable and multivariable analyses were performed using logistic regression model to identify CT variables associated with the diagnosis of active tuberculosis. ResultsA total of 92 patients with positive IGRA results who underwent CT examination were included. There were 54 men and 38 women with a mean age of 53.5±18 (SD) years (range: 40–68 years). Of them, 22 patients (24%) had positive Mycobacterium tuberculosis culture and 70 (76%) had latent tuberculosis. Among CT variables, consolidation had the greatest sensitivity (77%; 95%CI: 60–95%) and “tree-in-bud” the greatest specificity (97%; 95% CI: 93–100%) for the diagnosis of active tuberculosis. At univariable analysis “tree-in-bud”, splenic calcification and non-calcified lung nodules were the significant variables independently associated with active tuberculosis. At multivariable analysis, the adjusted odds ratio of “tree-in-bud” was 42.91 (95% CI: 5.62–327.42). Using an optimal threshold of 51 spots, quantitative IGRA yielded 64% sensitivity (95% CI: 44–84%) and 61% specificity (95% CI: 50–73%) for the diagnosis of active tuberculosis. ConclusionsIn a low incidence setting, chest CT, especially when “tree-in-bud” pattern is present, is superior to quantitative IGRA testing to identify patients with active tuberculosis among those with positive IGRA testing.

Osteomyelitis and Septic Arthritis Due to Burkholderia pseudomallei: A 10-Year Retrospective Melioidosis Study From South China.

Burkholderia pseudomallei is the causative agent of melioidosis, endemic mainly in tropical and subtropical areas. Its clinical manifestation is broad ranging from a localized skin lesion to a life-threatening systemic disease. Osteomyelitis and septic arthritis caused by B. pseudomallei are a rare, fatal illness, whose clinical features have not been illustrated in mainland China. Over 10 years (2010 to 2019), of 334 culture-confirmed melioidosis in Hainan province, China, 44 patients (13.2%) were confirmed to have osteomyelitis and septic arthritis through the combination of clinical features, imaging examination and microbiological culture. Herein, we summarized these 44 patients’ clinical manifestations, demographical features, antibiotic treatment, and outcomes. Of them, osteomyelitis and septic arthritis accounted for 25 (56.8%) and 15 (34.1%), respectively, and 4 patients (9.1%) had both. The gender ratio of male/female was approximately 13.7:1; diabetes mellitus was the most common risk factor (38/44, 86.4%); imipenem and trimethoprim/sulfamethoxazole were the most frequently used antibiotics. Most B. pseudomallei strains were isolated from blood samples (41/44, 93.2%). After surgical handling, antibiotic treatment, or both, 9 patients died, with a mortality rate of 20.5%. In summary, in melioidosis endemic areas, for patients with both localized manifestations of joint and bone and a positive B. pseudomallei blood culture, increased awareness is required for melioidotic osteomyelitis and septic arthritis.

EPIDEMIOLOGY OF NOSOCOMIAL INFECTION COMPLICATIONS IN A SURGICAL CLINIC

The analysis of the data of literary sources of domestic and foreign researchers on the problem of the occurrence and development of nosocomial infections in general and in the surgical departments in particular is carried out. The relevance of the study is confirmed by the following data: the spread of nosocomial infections in the Russian Federation is 2.5 million annually; the minimum damage inflicted by them in Russia alone is approximately 6-7 million rubles. The data of foreign scientists have been studied, suggesting that infections in the field of hirirurgic intervention were recorded in 13% of cases after performing clean operations, in 16% after and in 29% after . In St. Petersburg, with selective studies, the frequency of infections in the field of surgical intervention revealed 9% of patients among 1,500 operated It was revealed that the number of potential causative agents of nosocomial infections increases every year due to opportunistic bacteria that differ in biological characteristics from hospital strains and have multiple drug antibiotic resistance. A retrospective and prospective analysis of the frequency of occurrence of microorganisms in patients of the surgical department of 2008-2019 was carried out. The microbial spectrum and prevalence of nosocomial infection pathogens in the surgical department were investigated. An epidemiological analysis of the causative agents of nosocomial infection in patients with pneumonia, infections in the surgical field and urinary tract, as well as with generalized infections, was carried out. The analysis of the bacterial flora of the clinical microbiological culture of the wound discharge, sputum, urine and blood was carried out. The following microorganisms were most prevalent in these samples: Staphylococcus aureus, Acinetobacter baumannii, Candida albicans, Klebsiella pneumonia. A tendency to increase the proportion of Candida albicans in patients of the surgical department, as well as a high prevalence of Staphylococcus epidermidis in blood cultures, was revealed.

Rapid detection of biofilm with modified alcian blue staining: In-vitro protocol improvement and validation with clinical cases.

For chronic wounds, biofilm infection is a critical issue because it can tip the scales toward an unhealing state. Biofilm-based wound therapy has been extensively advocated. However, point-of-care biofilm diagnosis still largely relies on clinical judgment. In this study, we aimed to develop a rapid tool for diagnosing wound biofilm presence by alcian blue staining. First, we sought to optimize alcian blue staining using a colorimetric-based approach to detect the biofilm, specifically targeting polysaccharides in the extracellular polymeric substances. Among examined transfer membranes and cationic detergents at various concentrations, we selected a positively charged nylon transfer membrane for sample loading, and 1% cetyl trimethyl ammonium chloride (CTAC) as the blocking solution. After sample loading and blocking, the membrane was immersed in alcian blue solution for staining, followed by immersion in 1% CTAC to decrease background noise. Each step required only 30 seconds, and the whole procedure was completed within a few minutes. In the second part of this study, we enrolled 31 patients with chronic wounds to investigate the predictive validity of biofilm detection for unhealed wounds at a 1-month follow-up visit. Among the 18 cases with positive wound biofilm staining, 15 wounds (83.3%) were not healed at the 1-month follow-up visit. Only three unhealed wounds (30%) produced in negative staining cases. This finding indicates that biofilm infection is associated with poor healing outcome for chronic wounds. Moreover, our staining results correlated well with the clinical microbiological culture assessment (83.9% consistency; 95.2% sensitivity, and 60% specificity). In conclusion, the modified alcian blue staining protocol used here represents a rapid and sensitive procedure for detecting biofilm in chronic wounds. This technique provides a practical point-of-care approach for detection of wound biofilm, the implementation of which may improve clinical outcomes for chronic wound patients. Additional studies are required to validate this method.

Metagenomic identification of severe pneumonia pathogens in mechanically-ventilated patients: a feasibility and clinical validity study

BackgroundMetagenomic sequencing of respiratory microbial communities for pathogen identification in pneumonia may help overcome the limitations of culture-based methods. We examined the feasibility and clinical validity of rapid-turnaround metagenomics with Nanopore™ sequencing of clinical respiratory specimens.MethodsWe conducted a case-control study of mechanically-ventilated patients with pneumonia (nine culture-positive and five culture-negative) and without pneumonia (eight controls). We collected endotracheal aspirates and applied a microbial DNA enrichment method prior to metagenomic sequencing with the Oxford Nanopore MinION device. For reference, we compared Nanopore results against clinical microbiologic cultures and bacterial 16S rRNA gene sequencing.ResultsHuman DNA depletion enabled in depth sequencing of microbial communities. In culture-positive cases, Nanopore revealed communities with high abundance of the bacterial or fungal species isolated by cultures. In four cases with resistant clinical isolates, Nanopore detected antibiotic resistance genes corresponding to the phenotypic resistance in antibiograms. In culture-negative pneumonia, Nanopore revealed probable bacterial pathogens in 1/5 cases and Candida colonization in 3/5 cases. In controls, Nanopore showed high abundance of oral bacteria in 5/8 subjects, and identified colonizing respiratory pathogens in other subjects. Nanopore and 16S sequencing showed excellent concordance for the most abundant bacterial taxa.ConclusionsWe demonstrated technical feasibility and proof-of-concept clinical validity of Nanopore metagenomics for severe pneumonia diagnosis, with striking concordance with positive microbiologic cultures, and clinically actionable information obtained from sequencing in culture-negative samples. Prospective studies with real-time metagenomics are warranted to examine the impact on antimicrobial decision-making and clinical outcomes.

245. Plasma and Respiratory Specimen Metagenomic Sequencing for the Diagnosis of Severe Pneumonia in Mechanically-Ventilated Patients

BackgroundMetagenomic sequencing of respiratory microbial communities may overcome the limitations of culture-based pneumonia diagnostics. Nonetheless, respiratory metagenomics requires high-quality specimens, may miss deep-seated infections and cannot distinguish colonization from infection. Plasma microbial cell-free DNA (mcfDNA) sequencing may offer a noninvasive alternative for culture-independent diagnosis and help refine interpretations of respiratory metagenomics.MethodsWe obtained concurrent plasma and endo-tracheal aspirate (ETA) samples from 29 mechanically-ventilated patients (15 culture-positive, 11 culture-negative pneumonia, 3 uninfected control patients). We performed plasma mcfDNA sequencing (Karius®Test, Redwood City, CA) and ETA metagenomics (MiNION, Oxford Nanopore Technologies). We compared sequencing results with clinical microbiologic cultures for identified DNA pathogens.ResultsUninfected control patients had a negative signal for mcfDNA in plasma and oral bacteria in ETA specimens. In culture-positive pneumonia samples, Karius testing identified a median of 2 pathogens per sample (range 0–10), which were concordant with clinical isolates in 11/15 (73%) cases (figure). In 5/11 (45%) of concordant cases, Karius and MiNION suggested polymicrobial infections with additional pathogens not identified by cultures. In culture-negative cases, Karius detected potential pathogens in 8/11 (73% cases), which matched the species identified in ETA specimens by MiNION. In cases of clinical aspiration, Karius detected more organisms (median 8, range 0–14) per sample mainly consisting of oral origin bacteria compared with cases without history of aspiration (median 1, range 0–6, P = 0.04).ConclusionMetagenomic sequencing in plasma and ETA samples showed good concordance between the blood and lung compartments as well as with culture results in pneumonia patients. Metagenomics revealed potential pathogens missed by cultures in ~75% of culture-negative pneumonias and suggested polymicrobial infections especially in cases with aspiration. Further research is needed to evaluate the clinical utility of real-time metagenomics for pneumonia diagnosis in mechanically ventilated patients. Disclosures All authors: No reported disclosures.

Differentiation between infected and non-infected wounds using an electronic nose

ObjectivesThe aim of this study was to explore whether an electronic nose, Aetholab, is able to discriminate between infected versus non-infected wounds, based on headspace analyses from wound swabs. MethodsA total of 77 patients participated in this pilot study. Each wound was assessed for infection based on clinical judgment. Additionally, two wound swabs were taken, one for microbiological culture and one for measurement with Aetholab. Diagnostic properties with 95% confidence intervals (95%CIs) of Aetholab were calculated with clinical judgment and microbiological culture results as reference standards. ResultsWith clinical judgment as reference standard, Aetholab had a sensitivity of 91% (95%CI 76–98) and a specificity of 71% (95%CI 55–84). Diagnostic properties were somewhat lower when microbiological culture results were used as reference standard: sensitivity 81% (95%CI 64–91), specificity 63% (95%CI 46–77). ConclusionsAetholab seems a promising diagnostic tool for wound infection given the diagnostic properties presented in this pilot study. A larger study is needed to confirm our results.

Emergency Department Environmental Contamination With Methicillin-Resistant Staphylococcus aureus After Care of Colonized Patients

Methicillin-resistant Staphylococcus aureus (MRSA) transmission dynamics in the emergency department (ED) are not well defined; environmental surfaces may serve as reservoirs for transmission. This study investigates the effectof patients with a history of MRSA colonization or infection on subsequent MRSA contamination of the ED environment. Adult ED patients with evidence of an MRSA-positive surveillance result or clinical microbiologic culture in the year preceding their current ED visit were enrolled. Cultures from 5 anatomic sites were obtained to detect active MRSA colonization. After patients' discharge and before environmental disinfection, up to 16 prespecified surfaces in their ED rooms were cultured. Strain typing was performed by repetitive-sequence polymerase chain reaction on all recovered MRSA isolates to determine concordance with the corresponding patient strain. Of 42 patients enrolled, 25 (60%) remained colonized with MRSA. Nineteen of the 25 ED rooms (76%) occupied by MRSA-colonized patients contained greater than or equal to 1 MRSA-contaminated environmental surface on patient discharge. Surfaces were more likely to be contaminated when rooms were occupied by patients colonized with MRSA at 1 body site (odds ratio 11.7; 95% confidence interval 1.5 to 91.5) and greater than or equal to 2 body sites (odds ratio 16.3; 95% confidence interval 3.1 to 86.8) compared with noncolonized patients. In 16 of the 19 ED rooms (84%) where MRSA was recovered, all environmental strains were concordant with the corresponding patient strain. Contamination of the ED environment with MRSA from actively colonized patients is common. Improved environmental surface disinfection may help reduce transmission of MRSA to ED health care professionals and patients during emergency care.

Association between rectal colonization with Highly Resistant Gram-negative Rods (HR-GNRs) and subsequent infection with HR-GNRs in clinical patients: A one year historical cohort study

ObjectiveRectal colonization with Highly Resistant Gram-negative Rods (HR-GNRs) probably precedes infection. We aimed to assess the association between rectal HR-GNR colonization and subsequent HR-GNR infection in clinical patients during a follow-up period of one year in a historical cohort study design.MethodsRectal HR-GNR colonization was assessed by culturing. Subsequent development of infection was determined by assessing all clinical microbiological culture results extracted from the laboratory information system including clinical data regarding HR-GNR infections. A multivariable logistic regression model was constructed with HR-GNR rectal colonization as independent variable and HR-GNR infection as dependent variable. Gender, age, antibiotic use, historic clinical admission and previous (HR-GNR) infections were included as possible confounders.Results1133 patients were included of whom 68 patients (6.1%) were colonized with a HR-GNR. In total 22 patients with HR-GNR infections were detected. Urinary tract infections were most common (n = 14, 63.6%), followed by bloodstream infections (n = 5, 22.7%) and other infections (n = 8, 36.4%). Eight out of 68 HR-GNR colonized patients (11.8%) developed a subsequent HR-GNR infection compared to 14 out of 1065 HR-GNR negative patients (1.3%), resulting in an odds ratio (95% CI) of 7.1 (2.8–18.1) in the multivariable logistic regression analyses.ConclusionsRectal colonization with a HR-GNR was a significant risk factor for a subsequent HR-GNR infection.This implies that historical colonization culture results should be considered in the choice of empirical antibiotic therapy to include coverage of the cultured HR-GNR, at least in critically ill patients.

Occurrence of acid erosion of the teeth, actinomycosis and polioencephalomalacia in flock of sheep fed wet low pectin citrus pulp

ABSTRACT: The citrus pulp can be used as a substitute in ruminant feed reducing costs and maintaining the nutritional quality of food. However, this compound should be used carefully so as not to cause harm to the animals. The present report aims to describe the occurrence of dental erosion, actinomycosis and polioencephalomalacia in sheep raised and kept with a wet low pectin citrus pulp based diet, composing 50% of roughage. Actinomycosis was diagnosed in five animals through clinical and radiographic examinations and microbiological culture, and, after treatment, three animals were cured. Polioencephalomalacia was confirmed in ten animals by clinical diagnostics, in nine out of ten animals by therapeutic diagnosis, and in one animal by post-mortem anatomopathological examination. According to the observed, we recommend caution when large amounts of citrus pulp are used as bulky food.

Non-tuberculous Mycobacterium Disease: Radiologic Manifestation in an Infant presenting with Respiratory Distress

Non-tuberculous mycobacterium (NTM) comprises distinct group of organisms with lymphadenitis and pulmonary infection as the common manifestation. The diagnosis of pulmonary disease is based on clinical manifestations, radiologic findings and microbiologic culture. The classic NTM infection may be indistinguishable from pulmonary TB. Non-classic infection has predilection to the middle lobe and lingula unlike tuberculosis which is commonly seen in the upper lobes. The disease may also present as hypersensitivity pneumonitis with ground glass like opacities, centrilobular nodules and air trapping on imaging. The knowledge of imaging manifestations of NTM will aid in timely diagnosis and treatment of the disease.Nepal Journal of Radiology Vol.5(1-2) 2015: 13-20

Prevalence and risk factors of chorioamnionitis in Dhaka, Bangladesh.

To estimate the association between chorioamnionitis, maternal risk factors and birth outcomes. A cross-sectional study of 600 pregnant women was conducted at a maternity center in Dhaka from January to October 2011. Outcomes included histologic, microbiologic and clinical chorioamnionitis. Log-binomial models assessed the association between risk factors and histologic chorioamnionitis (HC). Of the 552 women with placental specimens, 70 (12.7%) were classified with HC: 46 (65.7%) with and 24 (34.3%) without fetal involvement. HC was associated with non-physician care (relative risk [RR] 2.04, 95% confidence interval [CI] 1.04 to 4.00), home slab or hanging latrine (RR 1.69, 95% CI 1.10 to 2.62), and lack of tetanus toxoid (RR 1.80, 95% CI 1.03 to 3.14). Women with fever (RR 2.30, 95% CI 1.18 to 4.50) or discolored amniotic fluid (RR 1.74, 95% CI 1.08 to 2.81) had a higher risk of HC. Microbiologic and clinical chorioamnionitis were unreliable HC measures. Prevalence of HC is high; many cases are not captured by clinical diagnosis or microbiologic cultures.

When is pneumonia not pneumonia: a clinicopathologic study of the utility of lung tissue biopsies in determining the suitability of cadaveric tissue for donation.

Healthcare-associated pneumonia (HCAP) represents a major diagnostic challenge because of the relatively low sensitivity and specificity of clinical criteria, radiological findings, and microbiologic culture results. It is often difficult to distinguish between pneumonia, underlying pulmonary disease, or conditions with pulmonary complications; this is compounded by the often-subjective clinical diagnosis of pneumonia. We conducted this study to determine the utility of post-mortem lung biopsies for diagnosing pneumonia in tissue donors diagnosed with pneumonia prior to death. Subjects were deceased patients who had been hospitalized at death and diagnosed with pneumonia. Post-mortem lung biopsies were obtained from the anatomic portion of the cadaveric lung corresponding to chest radiograph abnormalities. Specimens were fixed, stained with hematoxylin and eosin, and read by a single board-certified pathologist. Histological criteria for acute pneumonia included intense neutrophilic infiltration, fibrinous exudates, cellular debris, necrosis, or bacteria in the interstitium and intra-alveolar spaces. Of 143 subjects with a diagnosis of pneumonia at time of death, 14 (9.8%) had histological evidence consistent with acute pneumonia. The most common histological diagnoses were emphysema (53%), interstitial fibrosis (40%), chronic atelectasis (36%), acute and chronic passive congestion consistent with underlying cardiomyopathy (25%), fibro-bullous disease (12%), and acute bronchitis (11%). HCAP represents a major diagnostic challenge because of the relatively low sensitivity and specificity of clinical criteria, radiological findings, and microbiologic testing. We found that attending physician-diagnosed pneumonia did not correlate with post-mortem pathological diagnosis. We conclude that histological examination of cadaveric lung tissue biopsies enables ascertainment or rule out of underlying pneumonia and prevents erroneous donor deferrals.