cefoxitin and Pneumonia--Bacterial

The lack of reliable predictors for the treatment response complicates decisions to initiate treatment in patients with Mycobacterium abscessus complex pulmonary disease (MABC-PD). We aimed to investigate whether baseline radiographic disease severity is associated with treatment outcome in MABC-PD.. We retrospectively analyzed 101 patients with MABC-PD (54 with M. abscessus-PD and 47 with M. massiliense-PD) treated in a tertiary referral hospital between January 2006 and December 2019. Using chest computed tomography images, baseline radiographic disease severity was quantitatively scored according to five categories of radiographic lesions (bronchiectasis, bronchiolitis, cavities, nodules, and consolidation).. Treatment success was achieved in 53.7% of patients with M. abscessus-PD and 85.1% of patients with M. massiliense-PD. Higher overall scores for baseline radiographic disease severity were associated with treatment failure in patients with M. massiliense-PD (aOR 1.35, 95% CI 1.02-1.79 for each 1-point increase in severity score), as well as in patients with M. abscessus-PD (aOR 1.15, 95% CI 1.00-1.33). This was particularly prominent in patients with overall severity score of ≥14 (aOR 31.16, 95% CI 1.12-868.95 for M. massiliense-PD and aOR 3.55, 95% CI 1.01-12.45 for M. abscessus-PD). Among variable radiographic abnormalities, the score for cavitary lesion severity was associated with treatment failure in patients with M. abscessus-PD (aOR 1.26, 95% CI 1.01-1.56), but not in patients with M. massiliense-PD.. Given the association between baseline radiographic disease severity and treatment outcome, initiating treatment should be actively considered before significant progression of radiographic lesions in patients with MABC-PD.

Topics: Aged; Amikacin; Anti-Bacterial Agents; Cefoxitin; Drug Therapy, Combination; Female; Humans; Imipenem; Infusions, Intravenous; Male; Middle Aged; Mycobacterium abscessus; Mycobacterium Infections, Nontuberculous; Pneumonia, Bacterial; Radiography, Thoracic; Retrospective Studies; Severity of Illness Index; Tomography, X-Ray Computed; Treatment Outcome

Topics: Aged; Anti-Bacterial Agents; Bacteremia; Bacterial Proteins; beta-Lactam Resistance; beta-Lactamases; Catheter-Related Infections; Cefoxitin; Cross Infection; Diarrhea; Drug Resistance, Multiple, Bacterial; Drug Therapy, Combination; Enterococcus faecalis; Glycopeptides; Humans; Klebsiella Infections; Klebsiella pneumoniae; Male; Pancreatic Neoplasms; Pneumonia, Bacterial; Postoperative Complications; Prostatitis; Substrate Specificity; Urinary Catheterization

The algorithms included in most automated systems used for antimicrobial susceptibility testing (e.g., Vitek 2) consider that Escherichia coli isolates resistant to cefoxitin are AmpC-hyperproducers and, consequently, resistant also to amoxycillin-clavulanate. However, a recent study revealed that 30% of E. coli clinical isolates resistant to cefoxitin remained susceptible in vitro to amoxycillin-clavulanate. The aim of the present study was to evaluate the in-vivo efficacy of amoxycillin-clavulanate in the treatment of an experimental model of pneumonia, using two clonally related isolates (with identical repetitive extragenic palindromic sequence (REP)-PCR patterns) of AmpC-non-hyperproducing and OmpF-lacking E. coli (Ec985 and Ec571) that were resistant to cefoxitin and susceptible to cefotaxime and amoxycillin-clavulanate. MICs were determined using a microdilution technique, and in-vitro bactericidal activity was tested using time-kill assays. The in-vivo efficacy of amoxycillin, amoxycillin-clavulanate and cefotaxime against both isolates was tested in a murine pneumonia model using immunocompetent C57BL/6 mice. Ec571 (a TEM-1/2 producer) was resistant to amoxycillin, whereas Ec985 (a TEM-1/2 non-producer) was susceptible. Amoxycillin, amoxycillin-clavulanate and cefotaxime were bactericidal for Ec985, and amoxycillin-clavulanate and cefotaxime were bactericidal for Ec571 at different concentrations and time-points, as determined using time-kill assays. Treatment with amoxycillin, amoxycillin-clavulanate and cefotaxime reduced the bacterial lung concentration of Ec985 compared with non-treated controls (p <0.05), whereas amoxycillin-clavulanate and cefotaxime showed efficacy against Ec571 when compared with the control and amoxycillin groups (p <0.05). Regardless of the exact underlying mechanism(s) of resistance, amoxycillin-clavulanate was effective in the experimental murine model in the treatment of pneumonia caused by AmpC-non-hyperproducing strains of E. coli resistant to cefoxitin.

Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Animals; Anti-Bacterial Agents; Bacterial Proteins; beta-Lactam Resistance; beta-Lactamase Inhibitors; beta-Lactamases; Cefotaxime; Cefoxitin; Drug Therapy, Combination; Escherichia coli; Escherichia coli Infections; Female; Lung; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Pneumonia, Bacterial; Specific Pathogen-Free Organisms

This work identifies an ISCR1-related bla(CTX-M-14) gene, which has never been reported before, from a clinical isolate of Escherichia coli. The bla(CTX-M-14) gene was preceded by an ISCR1 element that was followed by a class 1 integron containing three different insert gene cassettes, i.e., dfrA12, orfF, and aadA2.

Topics: Adult; Anti-Bacterial Agents; Base Sequence; beta-Lactamases; DNA Transposable Elements; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Humans; Integrons; Male; Microbial Sensitivity Tests; Molecular Sequence Data; Pneumonia, Bacterial; Sequence Analysis, DNA

A 14-year-old girl had progressive dyspnea and right lower chest pain for about 1 1/2 months and a weight loss of 3 kg in 2 months. Chest X-ray revealed right pleural effusion and a round infiltration over the right lower chest, initially suspected to be malignant. Image study revealed consolidation in the right middle and lower lobes with abscess-like lesions around the right lower pleura and transdiaphrenic involvement to the subphrenic region. The lesion had also invaded the intercostal muscle. The pleural abscess was obtained by fiberoptic thoracoscopy, and culture of the pus grew typical colonies of Actinobacillus actinomycetemcomitans. After the causative microorganism had been identified, cefoxitin was given for 2 weeks followed by oral amoxicillin (250 mg/6 h) for a total period of 3 months. Follow-up chest X-ray revealed resolution of the lung lesions and the patient recovered gradually without any sequelae.

Topics: Abscess; Actinobacillus Infections; Adolescent; Aggregatibacter actinomycetemcomitans; Amoxicillin; Cefoxitin; Cephamycins; Female; Humans; Penicillins; Pneumonia, Bacterial; Radiography, Thoracic; Subphrenic Abscess; Thoracic Diseases