Cephalosporin Hypersensitivity: Descriptive Analysis, Cross-Reactivity, and Risk Factors.

BACKGROUND: Cephalosporins, which belong to the beta-lactam therapeutic class, are increasingly used throughout the world. Few large studies on this issue have been conducted, and most of them have been performed as part of penicillin hypersensitivity studies. OBJECTIVE: We described our 26-year experience exploring cephalosporin drug hypersensitivity, from which we identified epidemiological and cross-reactivity data. METHODS: We included 476 patients who reported drug hypersensitivity reaction (DHR) to cephalosporin and underwent an allergy workup between January 1992 and July 2018 in the Allergy Unit of the University Hospital of Montpellier (France). According to their structural side chain R1 homology, we worked with 4 classes of cephalosporins. Logistic regression analysis was used to search for risk factors for hypersensitivity to cephalosporin (positive skin test [ST] or drug provocation test [DPT] results). RESULTS: Cephalosporin hypersensitivity was proven in 22.3% of the patients referred in our Unit, according to positive ST (51.9%) or DPT to the culprit drug (48.1%). One in 5 patients were children, and cephalosporin hypersensitivity was confirmed in 15% (47.6% of them by means of ST). In the cephalosporin hypersensitive population, initial reactions were mostly immediate (68.9%) and anaphylactic (72.7%). Cross-reactivity with aminopenicillins was the most frequent pattern of cross-reactivity. In multivariate analysis, immediate reactions (odds ratio [OR] = 3, 95% confidence interval [CI] [1.6-5.5], P < .001), anaphylactic shock (OR = 6.5, 95% CI [3.3-13.1], P < .001) and anaphylaxis (OR = 3.1, 95% CI [1.6-6.1], P < .001), and multiple reactions to the same or several cephalosporins (OR = 2.0, 95% CI [1-3.5], P = .04) were statistically associated with confirmed DHR. DPT was generally safe, but elicited anaphylaxis in 20% of patients. Systemic reactions during skin testing occurred in 9.1% of positive patients, almost always related to anaphylactic index reactions. Nonimmediate confirmed DHR to cephalosporins were rare and occurred in less than 10% of the positive patients. CONCLUSION: Almost a quarter of the tested patients were confirmed as hypersensitive to cephalosporins; sensitivity of skin testing was 51.9%, and thus, half of the positive patients needed a DPT to prove the diagnosis.

Emergence of Mycobacterium simiae: A retrospective study from a tertiary care center in Lebanon.

OBJECTIVE: The objective of this study is to describe the clinical significance of Mycobacterium simiae at a major tertiary care center in Lebanon. METHODS: This is a retrospective study of patients with positive cultures for M. simiae isolated between 2004 and 2016 at the American University of Beirut Medical Center. RESULTS: This study included 103 M. simiae isolates recovered from 51 patients. Their mean age was 62.7 years. The majority were males and smokers. Specimens were mostly from respiratory sources (97%). Common comorbidities included chronic lung disease (such as chronic obstructive pulmonary disease), solid tumor, systemic disease, and diabetes mellitus. Productive cough and dyspnea were the most common symptoms. Frequent radiographic findings were infiltrates and nodules on chest X-ray and nodules, infiltrates, and bronchiectasis on chest computed tomography scan. Among 18 tested isolates, 5.8% were resistant to clarithromycin, 11.7% to amikacin, and 70-100% to other antimicrobials. Out of 13 patients receiving early treatment, 5 noted improvement, one had recurrence of symptoms, two received alternative diagnosis, and five died. Two of those deaths were related to M. simiae. Common treatment regimens included clarithromycin in different combinations with trimethoprim-sulfamethoxazole, moxifloxacin, and amikacin. Moreover, clofazimine was used in only two patients whose isolates were resistant to all but one agent. Duration of treatment ranged from 6-24 months. CONCLUSION: In Lebanon, M. simiae is increasingly encountered with true infection rates of at least 47%. Furthermore, the prevalence of multidrug resistance among the Lebanese M. simiae isolates is very high limiting the treatment options.