Secondary bacterial infections and antibiotic resistance among tungiasis patients in Western, Kenya

Tungiasis or jigger infestation is a parasitic disease caused by the female sand flea Tunga penetrans. Secondary infection of the lesions caused by this flea is common in endemic communities. This study sought to shed light on the bacterial pathogens causing secondary infections in tungiasis lesions and their susceptibility profiles to commonly prescribed antibiotics. Participants were recruited with the help of Community Health Workers. Swabs were taken from lesions which showed signs of secondary infection. Identification of suspected bacteria colonies was done by colony morphology, Gram staining, and biochemical tests. The Kirby Bauer disc diffusion test was used to determine the drug susceptibility profiles. Out of 37 participants, from whom swabs were collected, specimen were positive in 29 and 8 had no growth. From these, 10 different strains of bacteria were isolated. Two were Gram positive bacteria and they were, Staphylococcus epidermidis (38.3%) and Staphylococcus aureus (21.3%). Eight were Gram negative namely Enterobacter cloacae (8.5%), Proteus species (8.5%), Klebsiellla species (6.4%), Aeromonas sobria (4.3%), Citrobacter species (4.3%), Proteus mirabillis(4.3%), Enterobacter amnigenus (2.1%) and Klebsiella pneumoniae (2.1%). The methicillin resistant S. aureus (MRSA) isolated were also resistant to clindamycin, kanamycin, erythromycin, nalidixic acid, trimethorprim sulfamethoxazole and tetracycline. All the Gram negative and Gram positive bacteria isolates were sensitive to gentamicin and norfloxacin drugs. Results from this study confirms the presence of resistant bacteria in tungiasis lesions hence highlighting the significance of secondary infection of the lesions in endemic communties. This therefore suggests that antimicrobial susceptibility testing may be considered to guide in identification of appropriate antibiotics and treatment therapy among tungiasis patients

Combined Use of In Vitro Phototoxic Assessments and Cassette Dosing Pharmacokinetic Study for Phototoxicity Characterization of Fluoroquinolones

The present study aimed to develop an effective screening strategy to predict in vivo phototoxicity of multiple compounds by combined use of in vitro phototoxicity assessments and cassette dosing pharmacokinetic (PK) studies. Photochemical properties of six fluoroquinolones (FQs) were evaluated by UV spectral and reactive oxygen species (ROS) assays, and phototoxic potentials of FQs were also assessed using 3T3 neutral red uptake phototoxicity test (3T3 NRU PT) and intercalator-based photogenotoxicity (IBP) assay. Cassette dosing pharmacokinetics on FQs was conducted for calculating PK parameters and dermal distribution. All the FQs exhibited potent UV/VIS absorption and ROS generation under light exposure, suggesting potent photosensitivity of FQs. In vitro phototoxic risks of some FQs were also elucidated by 3T3 NRU PT and IBP assay. Decision matrix for phototoxicity prediction was built upon these in vitro data, taken together with outcomes from cassette dosing PK studies. According to the decision matrix, most FQs were deduced to be phototoxic, although gatifloxacin was found to be less phototoxic. These findings were in agreement with clinical observations. Combined use of in vitro photobiochemical and cassette dosing PK data will be useful for predicting in vivo phototoxic potentials of drug candidates with high productivity and reliability

Development of Persister-FACSeq: a method to massively parallelize quantification of persister physiology and its heterogeneity

Bacterial persisters are thought to underlie the relapse of chronic infections. Knowledge of persister physiology would illuminate avenues for therapeutic intervention; however, such knowledge has remained elusive because persisters have yet to be segregated from other cell types to sufficient purity. This technical hurdle has stymied progress toward understanding persistence. Here we developed Persister-FACSeq, which is a method that uses fluorescence-activated cell sorting, antibiotic tolerance assays, and next generation sequencing to interrogate persister physiology and its heterogeneity. As a proof-of-concept, we used Persister-FACSeq on a library of reporters to study gene expression distributions in non-growing Escherichia coli, and found that persistence to ofloxacin is inversely correlated with the capacity of non-growing cells to synthesize protein. Since Persister-FACSeq can be applied to study persistence to any antibiotic in any environment for any bacteria that can harbor a fluorescent reporter, we anticipate that it will yield unprecedented knowledge of this detrimental phenotype