Azithromycin (AZ) is a broad-spectrum antibiotic with anti-inflammatory and anti-quorum sensing activity against biofilm forming bacteria such as Pseudomonas aeruginosa (Pa). AZ administered by oral or parenteral routes however, neither efficiently access nor remain in therapeutic doses inside pulmonary biofilm depths. Instead, inhaled nanocarriers loaded with AZ may revert the problem of low accessibility and permanence of AZ into biofilms, enhancing its antimicrobial activity. The first inhalable nanovesicle formulation of AZ: nanoarchaeosome-AZ (nanoARC-AZ) is here presented. NanoARC prepared with total polar archaeolipids (TPA, rich in 2,3-di-O-phytanyl-sn-glycero-1-phospho-(3'-sn-glycerol-1'-methylphosphate) (PGP-Me) from Halorubrum tebenquichense archaebacteria, consisted of ∽ 180 nm diameter nanovesicles, loaded with 0.28 w:w AZ:TPA. NanoARC-AZ displayed lower MIC and MBC, higher preformed biofilm disruptive and anti-PAO1 activity in biofilm than AZ. NanoARC penetrated and disrupted the structure of PAO1 biofilm within only 1 h. 2 mL of 15 μg/mL AZ nanoARC-AZ nebulized along 5 min rendered AZ doses compatible with in vitro antibacterial activity. The strong association between AZ and nanoARC bilayer, combined electrostatic attraction and trapping into perpendicular methyl groups of archaeolipids, as determined by Laurdan fluorescence anisotropy, generalized polarization and SAXS, was critical to stabilize during storage and endure shear forces of nebulization. NanoARC-AZ was non-cytotoxic on A549 cells and human THP-1 derived macrophages, deserving further preclinical exploration as enhancers of AZ anti-PAO1 activity.

We evaluated the efficacy of intermittent azithromycin and ethambutol therapy for non-cavitary Mycobacterium avium complex pulmonary disease (MAC-PD). Twenty-nine of 38 patients (76%) achieved sputum culture conversion after 12 months of treatment, and sputum smear positivity was an independent factor for failure to achieve culture conversion (adjusted odds ratio: 26.7; 95% confidence interval: 2.1-339.9; p = 0.011). Intermittent azithromycin and ethambutol could be an optional treatment regimen for non-cavitary MAC-PD.

Mycobacterium abscessus is an extensively drug-resistant opportunistic pathogen that can cause chronic otomastoiditis. There are no evidence-based treatment regimens for this severe infection. We treated four children with M. abscessus otomastoiditis with a structured regimen of topical imipenem and tigecycline, intravenous imipenem and tigecycline and oral clofazimine and azithromycin and adjunctive surgery. This structured approach led to cure, with one year of follow-up after treatment. Adverse events were frequent, mostly caused by tigecycline.

Enteric fever (formerly typhoid fever) is a bacterial illness caused by fecal-oral transmission of Salmonella typhi or paratyphi. In early 2018, an outbreak of Salmonella typhi resistant to third-generation cephalosporins, ampicillin, ciprofloxacin, trimethroprim-sulfamethoxazole, and chloramphenicol was reported in Pakistan. This strain, termed "extensively resistant typhi," has infected more than 5000 patients in endemic areas of South Asia, as well as travelers to and from these areas, including 5 cases in the United States. We present the case of one such child who developed extensively resistant enteric fever during a recent visit to Pakistan and required broader antimicrobial treatment than typically required. Clinicians should be aware that incoming cases of enteric fever may be nonsusceptible to commonly recommended antibiotics and that extensively resistant typhi requires treatment with carbapenems such as meropenem or azithromycin.

In the present study, antibiotic residues were detected in milk samples collected from the dairy herds located in Karnataka, India, by microbiological assay. Subsequently, the detected antibiotics were identified as azithromycin and tetracycline, by high-performance liquid chromatography, further both the antibiotics detected in the cow milk samples were found to be at high concentration (9708.7 and 5460 μg kg-1, respectively). We then investigated the effects of temperature and pH on the stabilities of azithromycin and tetracycline to determine the degradation rate constant k using first-order kinetic equation. Results indicated that significant reduction in stability and antibacterial activity of azithromycin solution when subjected to 70 and 100°C for 24 h. While stability of tetracycline was significantly reduced when subjected to 70 and 100°C for 24 h. However no significant reduction in antibacterial activity of tetracycline was observed at respective temperatures when compared with that of control. In addition, the stabilities of azithromycin and tetracycline were found to be decreased in acidic pH 4-5. The results of the present study revealed the high risk of contamination of milk sample with veterinary antibiotics and also demonstrated the effect of temperature and pH on stability of antibiotics. Therefore the study suggest that the qualitative and quantitative screening of milk for the presence of antibiotics need to be strictly performed to ensure safe drinking milk for consumers.

The effectiveness of azithromycin combined with full-mouth scaling procedures was compared to quadrant-wise scaling combined with the same dosage of azithromycin when treating periodontitis patients over a 6-month period. In this randomized clinical trial study, thirty-four individuals diagnosed with generalized stage III and IV periodontitis underwent baseline, 3-month, and 6-month post-treatment examinations. The study population was randomly assigned to either full-mouth scaling (FMS) or quadrant-wise scaling and root planning (QSRP) in addition to their taking of systemic azithromycin (500 mg/day) for three consecutive days. Periodontal probing depth (PD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI) were monitored along with the quantification of total bacterial load and red complex bacterial species (Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) in subgingival samples by real time polymerase chain reaction. The volume of gingival crevicular fluid (GCF) was also monitored over time. The primary outcomes included improvements of PD and CAL. Data was statistically analyzed through a repeated-measures analysis of variance (ANOVA) test, multiple least significant difference (LSD) comparisons, Kruskal-Wallis, Friedman, and paired Student t-tests (p<0.05). FMS and QSRP provided similar PD, CAL, GI, PI, and GCF improvements. After treatment, the FMS group displayed lower mean values of total bacterial load and red complex bacterial species in comparison to the QSRP group. FMS and QSRP in conjunction with systemic azithromycin appeared to be an effective and reliable short-term therapeutic approach for the treatment of generalized stage III and IV periodontitis. However, FMD demonstrated superiority in regard to the 6-month antibacterial effects when compared to QSRP.