599 MEDIASTINITIS SECONDARY TO ESOPHAGEAL PERFORATION: IT’S TOO LATE?

Mediastinitis secondary to esophageal perforation is a rare, progressive, and destructive disease that may often lead to an imminent risk of death. We describe a single center experience showing how early diagnosis and prompt intervention can reduce mortality and complications. Methods From February 2016 to December 2019, 15 consecutive patients were referred to the Emergency Unit of The AORN Cardarelli (Naples) with clinical and radiological (CT scan) diagnosis of acute mediastinitis secondary to oesophageal perforation (post endoscopy or after foreign body ingestion) and furthermore, referred to the Thoracic Surgery Unit, they underwent to early surgical treatment (cervicotomy and\or thoracotomy and chest drainage. Results For early detected case (occurred within 24 hours) an emergency thoracotomy/cervicotomy was performed with surgical repair. For late detected (referred from other hospitals) a Surgical esclusion (abdominal plus cervical) and toilette thoracotomy was performed in emergency. Reconstruction occurred in 5 cases with a median of 46 days after firts care. All patient were admitted to ICU unit and susbsequentily to the thoracic surgery ward. 30 days mortality occurred in two cases. Median hospital staying was 28 days, in six cases a redo surgery was necessary. Empiric antibiotic treatment was started before operation and reviewed under Infectivologist. Conclusion Mediastinitis secondary to esophageal perforation has a fulminating course with a potential risk of sepsis, pericarditis, and multiple organ failure. A prompt identification and an invasive treatment is the best and most successful option to reduce mortality and improve patient’s recovery.

Prevention and Management of Infectious Complications of Retrograde Intrarenal Surgery

Kidney stone disease (KSD) is a commonly encountered ailment in urologic practice. Urinary tract infection (UTI) is commonly associated with KSD, both as an etiology (e.g., struvite and carbonate apatite stones), and as a complication (i.e., obstructive pyelonephritis and post-operative UTI). Indeed, a significant portion of the economic burden of KSD is skewed toward stones associated with infection. UTI is the most common post-operative complication related to stone intervention with progression to urosepsis as a rare but serious consequence. Risk for infection is influenced by a variety of factors including co-morbid conditions, anatomic abnormalities, prior surgical procedures, and local anti-microbial susceptibility. Understanding these risks and the proper steps to mitigate them is an essential component in reducing post-operative morbidity and mortality. Retrograde intrarenal surgery is routinely used for the treatment of KSD. The objective of this review article is to examine the current literature and guidelines for the prevention and management of stone-related infectious complications associated with retrograde intrarenal surgery. Special attention will be given to the incidence, etiology, and antibiotic prophylaxis choice in the management of stone-related infections. Intraoperative risk mitigation techniques will be discussed in conjunction with the management of post-operative infections. Antibiotic stewardship and the potential benefits of reduced empiric antibiotic treatment will also be discussed.

Detection of β-lactamase genes (blaTEM, bla CTX-M and bla SHV) in uropathogens isolated from patients with UTI

Background: The problem of antibiotic resistance has become worldwide health issue among hospitalized patients in developing countries, where the inappropriate usage of antibiotics is common. The widespread occurrence of multidrug resistant strains (MDRS) of Escherichia coli (E. coli) and klebsiella pneumoniae (K. pneumoniae) is currently considered avital medical challenge. The identification of ESβL genes and their MDRS in widely isolated uropathogens may provide a helpful tool for choosing effective antibiotic therapy and clinical improvement. Objective: The aim of this study is to determine the prevalence of (bla.TEM, bla.CTX-M, and bla.SHV) β-lactamase DNAs in E. coli and K. pneumoniae, and MDRS of uropathogens E. coli and k. pneumoniae isolated from patients urine UTI diagnosed who were admitted to the Urology & Nephrology Center. Methodology: Clinical E. coli and K. pneumoniae isolates were isolated from urine specimens of UTI diagnosed patients. Microbiological techniques were utilised to identify the isolates. Antibiotics susceptibility analysis was done utilising the Vitek2 system (bioMérieux, Marcy l’Etoile, France). The double disc diffusion technique (DDDT) was used for detecting phenotypic ESBL in isolates. Using the traditional PCR technique, the ESBL genes were identified. Results: Antibiotic resistance of E. coli’s isolates to commonly used antibiotics was high (88.2% resistant to Amoxicillin/clavulanate, 83.5 % were resistant to Trimethoprim-sulfamethoxazole) while minimum resistance appeared against Amikacin (AK) 10.5% and Imipenem (IP) 14%. For isolates of K. pneumoniae, the resistance was higher for nitrofurantoin, ceftazidime, cefotaxime, ciprofloxacin 96.6%, 83.3 %,83.3%, 80% respectively .In our study, out of 115 isolates, E. coli and K. pneumoniae isolates, 81 (70.43%) were phenotypically positive for ESβL by Combination Disc Test (CDT). The most commonly molecularly detected ESBL genes were TEM 80% of K. pneumoniae isolates and 77.6% of E. coli isolates .followed by SHV 70% of K. pneumoniae isolates and 34.1% of E. coli isolates and finally, CTXM 67% of isolates of E. coli and 63.3% of isolates of K. pneumoniae. Conclusions: The current study concluded that a high rate of resistance has been developed in uropathogens with empiric antibiotic treatment. It emphasized the alarming role of β-lactamases, especially ESßLs in antibiotic

Antimicrobial Resistance Patterns and Antibiotic Use during Hospital Conversion in the COVID-19 Pandemic

Objective: To describe empirical antimicrobial prescription on admission in patients with severe COVID-19, the prevalence of Hospital-Acquired Infections, and the susceptibility patterns of the causing organisms. Methods: In this prospective cohort study in a tertiary care center in Mexico City, we included consecutive patients admitted with severe COVID-19 between March 20th and June 10th and evaluated empirical antimicrobial prescription and the occurrence of HAI. Results: 794 patients with severe COVID-19 were admitted during the study period. Empiric antibiotic treatment was started in 92% of patients (731/794); the most frequent regimes were amoxicillin-clavulanate plus atypical coverage in 341 (46.6%) and ceftriaxone plus atypical coverage in 213 (29.1%). We identified 110 HAI episodes in 74/656 patients (11.3%). Ventilator-associated pneumonia (VAP) was the most frequent HAI, in 56/110 (50.9%), followed by bloodstream infections (BSI), in 32/110 (29.1%). The most frequent cause of VAP were Enterobacteriaceae in 48/69 (69.6%), followed by non-fermenter gram-negative bacilli in 18/69 (26.1%). The most frequent cause of BSI was coagulase negative staphylococci, in 14/35 (40.0%), followed by Enterobacter complex in 7/35 (20%). Death occurred in 30/74 (40.5%) patients with one or more HAI episodes and in 193/584 (33.0%) patients without any HAI episode (p < 0.05). Conclusion: A high frequency of empiric antibiotic treatment in patients admitted with COVID-19 was seen. VAP and BSI were the most frequent hospital-acquired infections, due to Enterobacteriaceae and coagulase negative staphylococci, respectively.

Acute Hematogenous Escherichia coli Osteomyelitis of the Fibula in an Adolescent Girl

Introduction: Acute hematogenous osteomyelitis (AHO) usually occurs in the first two decades of life. Evidence shows that 50% of patients with AHO are younger than five years. This infection typically affects the metaphyseal region of long tubular bones, whereas the fibula is rarely involved. Staphylococcus aureus is the causative agent of AHO in the majority of cases, while Escherichia coli is isolated rather uncommonly beyond the neonatal period. Case Presentation: Herein, we describe the case of an adolescent girl who was treated medically and surgically for AHO with an unusual location in the proximal fibula, caused by E. coli. The source of the causative agent remained unknown after the patient had been evaluated for possible urinary tract infection and underlying immune system defect. Conclusions: The fibula is a rare anatomic location for AHO, and such cases may pose a diagnostic challenge. Lack of response to empiric antibiotic treatment in patients with AHO may indicate the involvement of an uncommon pathogen, which is not susceptible to standard empiric antimicrobials aimed to target S. aureus as the most likely pathogen. In such instances, prompt surgical intervention can help determine the causative pathogen and optimize antimicrobial treatment.

Etiology of community-acquired pneumonia in adults: a systematic review

Background The etiology of community-acquired pneumonia (CAP) has evolved since the beginning of the antibiotic era. Recent guidelines encourage immediate empiric antibiotic treatment once a diagnosis of CAP is made. Concerns about treatment recommendations, on the one hand, and antibiotic stewardship, on the other, motivated this review of the medical literature on the etiology of CAP. Methods We conducted a systematic review of English-language literature on the etiology of CAP using methods defined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed using a combination of the keywords ‘pneumonia’, ‘CAP’, ‘etiology’, ‘microbiology’, ‘bacteriology’, and ‘pathogen’. We examined articles on antibiotics that were develop to treat pneumonia. We reviewed all ‘related articles’ as well as studies referenced by those that came up in the search. After we excluded articles that did not give sufficient microbiological data or failed to meet other predetermined criteria, 146 studies remained. Data were stratified into diagnostic categories according to the microbiologic studies that were done; results are presented as the percentage in each category of all cases in which an etiology was established. Results Streptococcus pneumoniae remains the most common cause of CAP although declining in incidence; this decline has been greater in the US than elsewhere. Haemophilus influenzae is the second most common cause of CAP, followed by Staphylococcus aureus and Gram negative bacilli. The incidence of all bacteria as causes of CAP has declined because, with routine use of PCR for viruses, the denominator, cases with an established etiology, has increased. Viruses were reported on average in about 10% of cases, but recent PCR-based studies identified a respiratory virus in about 30% of cases of CAP, with substantial rates of viral/bacterial coinfection. Conclusion The results of this study justify current guidelines for initial empiric treatment of CAP. With pneumococcus and Haemophilus continuing to predominate, efforts at antibiotic stewardship might be enhanced by greater attention to the routine use of sputum Gram stain and culture. Because viral/bacterial coinfection is relatively common, the identification of a virus by PCR does not, by itself, allow for discontinuation of the antibiotic therapy.

Fever in the Young Infant

Fever is the most common complaint of children who present to the emergency department. Approximately 12% of febrile neonates (aged 0–28 days) and young infants (aged 29—56 days) have serious bacterial infections (bacteremia, meningitis, urinary tract infections, pneumonia, bacterial gastroenteritis, and osteomyelitis). The evaluation and management of the febrile neonate and febrile young infant can be confusing. All febrile neonates require diagnostic testing, treatment with antibiotics, and hospital admission. The workup of the febrile young infant is more controversial. These patients should undergo blood and urine testing, but the need for lumbar puncture is controversial, as is the need for empiric antibiotic treatment. The disposition of these patients will depend on the results of these screening tests.

103. Empiric Antibiotic Susceptibility Using a Traditional vs. Syndromic Antibiogram-Implications for Antimicrobial Stewardship Programs

Background A primary tenet of antimicrobial stewardship programs (ASPs) is to establish empiric antibiotic treatment recommendations. While traditional antibiograms are useful, intrinsic variability in susceptibility exists when stratifying by source and/or location. In contrast, a syndromic antibiogram displays the likelihood of adequate coverage for a specific infection syndrome, considering the weighted incidence of pathogens causing that syndrome. The aim of the study was to compare antibiotic susceptibilities using a traditional versus syndromic antibiogram. Methods Between 2016–2019, 20 US institutions per year submitted up to 250 consecutive targeted gram-negative pathogens from hospitalized patients as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART). MICs were determined by broth microdilution and interpreted using 2020 CLSI breakpoints, except for imipenem/relebactam (I/R) for which FDA breakpoints were used. The traditional antibiogram included the 3 most common Gram-negative pathogens from all sources and represented critical organisms considered for empiric antibiotic coverage; the syndromic antibiogram included the 3 most commonly isolated Gram-negative pathogens from a respiratory source based on patient location. Results 17,561 Gram-negative isolates, including 6,654 lower respiratory isolates were evaluated. The top 3 most common Gram-negative organisms included: E. coli (n=6095, 44%), Klebsiella spp. (n=4097, 30%), P. aeruginosa (n=3649, 26%). Cumulative susceptibilities were comparable using a traditional vs. syndromic antibiogram (Figure 1); however, cefepime (FEP), piperacillin/tazobactam (TZP), and meropenem (MEM) susceptibilities were 5 – 8% lower when stratified by patient location (Figure 2) and ≥10% for P. aeruginosa (Figure 3). Ceftolozane/tazobactam (C/T) and I/R demonstrated ≥90% susceptibility regardless of respiratory source or patient location. Figure 1. Cumulative susceptibility of E. coli, Klebsiella spp, and P. aeruginosa for traditional vs. syndromic antibiogram Figure 2. Syndromic antibiogram evaluating cumulative susceptibility of E. coli (n = 637), Klebsiella spp. (n = 1190) and P. aeruginosa (n = 1997) respiratory isolates stratified by patient location Figure 3. Syndromic antibiogram evaluating susceptibility of P. aeruginosa (n = 1997) respiratory isolates stratified by patient location Conclusion Our analysis demonstrated that susceptibilities were lower for first-line agents when stratified by ICU and P. aeruginosa. ASPs should consider syndromic antibiograms based on source and patient location to optimize empiric antibiotic therapy recommendations. Disclosures Kenneth Klinker, PharmD, Merck & Co, Inc (Employee) Karri A. Bauer, PharmD, Merck Research Laboratories (Employee) C. Andrew DeRyke, PharmD, Merck & Co., Inc. (Employee, Shareholder) Levita K. Hidayat, PharmD BCIDP, Merck & Co (Employee)