Effect of ß-lactamase production and ß-lactam instability on MIC testing results for Mycobacterium abscessus.

OBJECTIVES: Limited treatment options available for Mycobacterium abscessus infections include the parenteral ß-lactam antibiotics cefoxitin and imipenem, which show moderate in vitro activity. Other ß-lactam antibiotics (except meropenem) have no considerable in vitro activity, due to their rapid hydrolysis by a broad-spectrum ß-lactamase (Bla_Mab). We here addressed the impact of ß-lactamase production and ß-lactam in vitro stability on M. abscessus MIC results and determined the epidemiological cut-off (ECOFF) values of cefoxitin, imipenem and meropenem. METHODS: By LC high-resolution MS (LC-HRMS), we assessed the in vitro stability of cefoxitin, imipenem and meropenem. M. abscessus ATCC 19977 strain and its isogenic blaMab deletion mutant were used for MIC testing. Based on MIC distributions for M. abscessus clinical strains, we determined ECOFFs of cefoxitin, imipenem and meropenem. RESULTS: A functional Bla_Mab increased MICs of penicillins, ceftriaxone and meropenem. LC-HRMS data showed significant degradation of cefoxitin, imipenem and meropenem during standard antibiotic susceptibility testing procedures. MIC, MIC50 and ECOFF values of cefoxitin, imipenem and meropenem are influenced by incubation time. CONCLUSIONS: The results of our study support administration of imipenem, meropenem and cefoxitin, for treatment of patients infected with M. abscessus. Our findings on in vitro instability of imipenem, meropenem and cefoxitin explain the problematic correlation between in vitro susceptibility and in vivo activity of these antibiotics and question the clinical utility of susceptibility testing of these chemotherapeutic agents.

Acute Toxicity Associated With the Recreational Use of the Novel Psychoactive Benzofuran N-methyl-5-(2 aminopropyl)benzofuran.

N-methyl-5-(2 aminopropyl)benzofuran (5-MAPB) is a novel psychoactive benzofuran, created by N-methylation of 5-(2-aminopropyl)benzofuran (5-APB), which shares structural features with methylenedioxymethamphetamine (MDMA). To our knowledge, no case of 5-MAPB-related toxicity has been published in the scientific literature. We report a case of oral 5-MAPB exposure confirmed by liquid chromatography-tandem mass spectrometry in a 24-year-old previously healthy white man. Observed symptoms and signs such as paleness, cold and clammy skin, hypertension, elevated high-sensitive troponin T level, tachycardia, ECG change, diaphoresis, mild hyperthermia, mydriasis, tremor, hyperreflexia, clonus, agitation, disorientation, hallucinations, convulsions, reduced level of consciousness, and creatine kinase level elevation (305 IU/L) were compatible with undesired effects related to 5-APB or MDMA exposure. Signs and symptoms resolved substantially within 14 hours with aggressive symptomatic treatment, including sedation with benzodiazepines, external cooling, analgesia and sedation with fentanyl-propofol, and treatment with urapidil, an α-receptor-blocking agent. 5-MAPB showed first-order elimination kinetics with a half-life of 6.5 hours, comparable to the half-life of MDMA. According to the chemical structure, this case report, and users' Web reports, 5-MAPB appears to have an acute toxicity profile similar to that of 5-APB and MDMA, with marked vasoconstrictor effect.

Topical Timolol for Infantile Hemangiomas: Evidence for Efficacy and Degree of Systemic Absorption.

BACKGROUND: Topical use of timolol for infantile hemangiomas has recently emerged with promising results. It is unknown whether topical ß-blockers act locally or if their effect is partly due to systemic absorption. This study investigates whether topically applied timolol is absorbed and reports on the efficacy of this treatment. METHODS: We treated 40 infants with small proliferating hemangiomas with topical timolol gel 0.5% twice daily and assessed urinary excretion and serum levels in a proportion of patients. Clinical response was evaluated on a visual analog scale of standardized photographs after 1, 2, 3, and 5 months. RESULTS: Forty infants with a median age of 18 weeks (range 2-35 wks) were included; 23 (58%) had superficial and 17 (42%) mixed-type hemangiomas. The median size was 3 cm(2) (range 0.1-15 cm(2) ) and nine hemangiomas were ulcerated. The hemangiomas improved significantly during treatment, with a median increase in visual analog scale of 7 points after 5 months (p < 0.001). Urinalysis for timolol was performed in 24 patients and was positive in 20 patients (83%). In three infants, serum levels of timolol were also measured and were all positive (median 0.16 ng/mL [range 0.1-0.18 ng/mL]). No significant side effects were recorded. CONCLUSION: Topical therapy with timolol is effective for infantile hemangiomas, but systemic absorption occurs. Serum levels in our patients were low, suggesting that using timolol for small hemangiomas is safe, but caution is advised when treating ulcerated or large hemangiomas, very young infants, or concomitantly using systemic propranolol.

Acute toxicity associated with the recreational use of the novel dissociative psychoactive substance methoxphenidine.

INTRODUCTION: Methoxphenidine is a novel dissociative designer drug of the diarylethylamine class which shares structural features with phencyclidine (PCP), and is not at present subject to restrictive regulations. There is very limited information about the acute toxicity profile of methoxphenidine and the only sources are anonymous internet sites and a 1989 patent of the Searle Company. We report a case of analytically confirmed oral methoxphenidine toxicity. CASE DETAILS: A 53-year-old man was found on the street in a somnolent and confusional state. Observed signs and symptoms such as tachycardia (112 bpm), hypertension (220/125 mmHg), echolalia, confusion, agitation, opisthotonus, nystagmus and amnesia were consistent with phencyclidine-induced adverse effects. Temperature (99.1°F (37.3°C)) and peripheral oxygen saturation while breathing room air (99%) were normal. Laboratory analysis revealed an increase of creatine kinase (max 865 U/L), alanine aminotransferase (72 U/L) and gamma-glutamyl transpeptidase (123 U/L). Methoxphenidine was identified by a liquid chromatography tandem mass spectrometry toxicological screening method using turbulent flow online extraction in plasma and urine samples collected on admission. The clinical course was favourable and signs and symptoms resolved with symptomatic treatment. CONCLUSION: Based on this case report and users' web reports, and compatible with the chemical structure, methoxphenidine produces effects similar to those of the arylcyclohexylamines, as PCP.

Ketamine-like effects after recreational use of methoxetamine.

Methoxetamine, the N-ethyl derivative of ketamine, is a novel recreational drug that is not at present subject to restrictive regulations in most countries. To our knowledge, no case of methoxetamine abuse has been published to date in the scientific literature, and the only sources of information are illegal drug users' Web discussion forums. We report the first case of analytically confirmed intravenous methoxetamine abuse in a 19-year-old man. Observed signs and symptoms such as tachycardia, hypertension, confusion, agitation, stupor, ataxia, mydriasis, and nystagmus were consistent with ketamine-induced adverse effects and resolved with symptomatic treatment. According to this case report, user Web reports, and the chemical structure, methoxetamine produces ketamine-like effects. Complete recovery can be expected with supportive care.

Therapeutic drug monitoring by LC-MS-MS with special focus on anti-infective drugs.

Liquid chromatography coupled to mass spectrometry nowadays plays an important role in the field of therapeutic drug monitoring (TDM), especially of new compounds for which no immunoassays are available. This paper reviews LC-MS(-MS) methods published recently for anti-infective drugs: antiretroviral drugs, other antiviral drugs, antibacterial drugs, antihelmintic drugs, antimalarial drugs, and other antiprotozoal drugs. An overview of the different methods is given, with special focus on selection of the internal standard and validation procedures.