Piperacillin/Tazobactam Use vs Cefepime May Be Associated With Acute Decompensated Heart Failure.

Background: Piperacillin/tazobactam (PTZ) has been cautiously used or avoided in patients with a history of heart disease due to concern for heart failure (HF) exacerbation given its relatively high sodium content. However, no prior studies have established this association. Methods: The Antimicrobial Stewardship Team at the James H. Quillen Veterans Affairs Medical Center reviewed the use of PTZ vs the comparator antibiotic, cefepime, in 2 consecutive years to determine whether the use of PTZ was more likely to be associated with acute decompensation of HF. Records of 389 veterans hospitalized in 2018 and 2019 were reviewed and included in this study. Results: Acute decompensation of HF was significantly associated with the use of PTZ (n = 25; 12.3%) compared with cefepime (n = 4; 2.2%) (P < .001). Additionally, hospital readmissions due to HF were higher in the PTZ group compared with the cefepime group (11 vs 1, P = .02). There were no significant differences identified in the length of stay or overall mortality between 204 patients who received PTZ compared with 185 patients who received cefepime (P = .54 and P = .63, respectively). Conclusions: PTZ use was significantly associated with a higher incidence of acute decompensation of HF and hospital readmission with HF exacerbation compared with cefepime. PTZ use among hospitalized patients with a history of HF should be carefully monitored or avoided.

Mycobacterium chimaera infection masquerading as a lung mass in a healthcare worker.

Mycobacterium chimaera, a nontuberculous mycobacterium, is a member of the Mycobacterium avium complex (MAC). This microorganism has recently gained significant notoriety for its association with outbreaks in patients exposed to contaminated heater -cooler devices used during open heart surgeries. We report a case of Mycobacterium chimaera pulmonary infection in a healthcare worker who presented with cough, low grade fever and weight loss with evidence of a lung mass that was initially thought to be a tumor on CT scan imaging. The patient underwent partial left lung lobectomy and pathology revealed necrotizing granulomas with acid fast bacilli and a culture grew M. chimaera. The patient received combination antimycobacterial therapy according to susceptibility results for twelve months with complete resolution of his symptoms and radiographic findings. Infection Control investigation could not find a source of infection in the hospital where he worked during the last ten years. However, the patient rotated in different hospitals before coming to work at this facility and assisted in surgeries in several operating rooms where the heater-cooler devices in question were used.

Peritoneal lavage using chlorhexidine gluconate at the end of colon surgery reduces postoperative intra-abdominal infection in mice.

BACKGROUND: The use of peritoneal lavage with antiseptic solutions after bowel surgery remains controversial. This study compared peritoneal lavage using chlorhexidine gluconate at low concentrations and normal saline in mice with cecal ligation and perforation. METHODS: A total of 180 mice were randomized to six groups. Groups A, B, and C received one-time intraperitoneal injections of normal saline, chlorhexidine gluconate 0.05%, and chlorhexidine gluconate 0.025%, respectively. Groups D, E, and F were all subject to cecal ligation and perforation, then underwent partial cecectomy and peritoneal lavage with normal saline only, chlorhexidine gluconate 0.05% followed by normal saline, and chlorhexidine gluconate 0.025% followed by normal saline, respectively. Animals were followed postoperatively then sacrificed and examined at necropsy for occurrence of intra-abdominal abscesses, adhesions, or other pathology. RESULTS: A total of 48 mice (26.7%) developed postoperative intra-abdominal abscesses. Group E mice that had chlorhexidine gluconate 0.05% lavage had significantly lower incidence of postoperative intra-abdominal abscesses compared with that of group D mice that had saline lavage only (P = 0.0113). There was no significant difference in occurrence of macroscopic adhesions among mice groups that had or did not have surgery. (P = 1 and P = 0.3728). Microscopic peritoneal fibrosis occurred significantly more among group E mice that had chlorhexidine gluconate 0.05% lavage compared with group D mice that had saline lavage only (P = <0.005). There was no significant difference in postoperative mortality between surgical groups (P = 0.8714). CONCLUSIONS: Chlorhexidine gluconate 0.05% peritoneal lavage after partial colectomy (cecectomy) in mice reduces postoperative intra-abdominal infection without significant macroscopic adhesion formation.

Pulmonary infection with caseating mediastinal lymphadenitis caused by Mycobacterium gordonae.

It is often difficult to discern true mycobacterial infection from colonization due to Mycobacterium gordonae (M. gordonae) since this organism is ubiquitous and is commonly an innocuous saprophyte. This study reports a rare case of caseating hilar adenopathy and pulmonary disease caused by M. gordonae in a patient with chronic obstructive pulmonary disease (COPD) and rheumatoid arthritis (RA) on maintenance steroids and methotrexate. Pathologic exam and cultures of lymph node excision biopsy and bronchoalveolar lavage (BAL) confirmed the diagnosis. Triple antimycobacterial therapy with azithromycin, ethambutol and rifabutin was administered. The patient had significant clinical and radiologic improvement and follow-up cultures confirmed microbiologic cure. Mycobacterium gordonae can be a rare cause of significant pulmonary infection, and positive sputum or BAL cultures for M. gordonae should not be automatically discarded and considered as nonpathogenic contaminants or colonizing organisms, especially in immunocompromised hosts with comorbidities. A detailed review of the case and relevant literature is provided.

Combining cytomorphology and serology for the diagnosis of cat scratch disease.

Cat scratch disease (CSD) is a self limited zoonotic disease that presents most commonly as a regional lymphadenopathy. We are reporting a case of a 25-year-old male patient who presented with fever and large right inguinal lymphadenopathy. The diagnosis of cat scratch disease was confirmed based on the characteristic cytopathological features on aspirate smears from the lymph node and the serological titers for Bartonella henselae. This case report emphasizes the importance of combining Bartonella serology, and cytopathology in the diagnostic work-up of febrile lymphadenopathy and suspected CSD since the culture of this organism is arduous.

Guide to selection of fluoroquinolones in patients with lower respiratory tract infections.

Newer fluoroquinolones such as levofloxacin, moxifloxacin, gatifloxacin and gemifloxacin have several attributes that make them excellent choices for the therapy of lower respiratory tract infections. In particular, they have excellent intrinsic activity against Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and the atypical respiratory pathogens. Fluoroquinolones may be used as monotherapy to treat high-risk patients with acute exacerbation of chronic bronchitis, and for patients with community-acquired pneumonia requiring hospitalisation, but not admission to intensive care. Overall, the newer fluoroquinolones often achieve clinical cure rates in > or =90% of these patients. However, rates may be lower in hospital-acquired pneumonia, and this infection should be treated on the basis of anticipated organisms and evaluation of risk factors for specific pathogens such as Pseudomonas aeruginosa. In this setting, an antipseudomonal fluoroquinolone may be used in combination with an antipseudomonalbeta-lactam. Concerns are now being raised about the widespread use, and possibly misuse, of fluoroquinolones and the emergence of resistance among S. pneumoniae, Enterobacteriaceae and P. aeruginosa. A number of pharmacokinetic parameters such as the peak concentration of the antibacterial after a dose (C(max)), and the 24-hour area under the concentration-time curve (AUC24) and their relationship to pharmacodynamic parameters such as the minimum inhibitory and the mutant prevention concentrations (MIC and MPC, respectively) have been proposed to predict the effect of fluoroquinolones on bacterial killing and the emergence of resistance. Higher C(max)/MIC or AUC24/MIC and C(max)/MPC or AUC24/MPC ratios, either as a result of dose administration or the susceptibility of the organism, may lead to a better clinical outcome and decrease the emergence of resistance, respectively. Pharmacokinetic profiles that are optimised to target low-level resistant minor subpopulations of bacteria that often exist in infections may help preserve fluoroquinolones as a class. To this end, optimising the AUC24/MPC or C(max)/MPC ratios is important, particularly against S. pneumoniae, in the setting of lower respiratory tract infections. Agents such as moxifloxacin and gemifloxacin with high ratios against this organism are preferred, and agents such as ciprofloxacin with low ratios should be avoided. For agents such as levofloxacin and gatifloxacin, with intermediate ratios against S. pneumoniae, it may be worthwhile considering alternative dose administration strategies, such as using higher dosages, to eradicate low-level resistant variants. This must, of course, be balanced against the potential of toxicity. Innovative approaches to the use of fluoroquinolones are worth testing in further in vitro experiments as well as in clinical trials.

Methicillin-resistant staphylococcal infections: an important consideration for orthopedic surgeons.

Postoperative infections in joint prostheses and fracture-fixation devices commonly involve both MRSA and methicillin resistant coagulase-negative staphylococcus. In addition, community-acquired MRSA has also become an important consideration when infected patients are admitted to the hospital from the community. Preoperative colonization with MRSA and methicillin resistant coagulase-negative staphylococcus increases the risk of postoperative surgical site infections in orthopedic patients. Up to 5.3% of orthopedic patients are colonized with these organisms on hospital admission. Screening and decolonization of methicillin resistant staphylococci decrease the incidence of postoperative surgical site infections in the orthopedic patient. This may be particularly important in orthopedic implants given the difficulty encountered in treating infected prosthesis. Current US guidelines advocate screening for methicillin resistant staphylococci only when risk factors are present. Growing evidence suggests that screening and decolinization of all patients having elective orthopedic procedures, especially those including prosthetic implants, will decrease the incidence of postoperative infections. The infected prosthesis may be potentially salvaged if the clinical manifestations of infection have been present for < or = 10 days, the implant is stable, and the etiologic organisms are susceptible to oral antibiotics.