A method for rapid species identification of ticks may help clinicians predict the disease outcomes of patients with tick bites and may inform the decision as to whether to administer postexposure prophylactic antibiotic treatment. We aimed to establish a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) spectrum database based on the analysis of the legs of six tick vectors: Amblyomma variegatum , Rhipicephalus sanguineus , Hyalomma marginatum rufipes , Ixodes ricinus , Dermacentor marginatus , and Dermacentor reticulatus . A blind test was performed on a trial set of ticks to identify specimens of each species. Subsequently, we used MALDI-TOF MS to identify ticks obtained from the wild or removed from patients. The latter tick samples were also identified by 12S ribosomal DNA (rDNA) sequencing and were tested for bacterial infections. Ticks obtained from the wild or removed from patients ( R. sanguineus , I. ricinus , and D. marginatus ) were accurately identified using MALDI-TOF MS, with the exception of those ticks for which no spectra were available in the database. Furthermore, one damaged specimen was correctly identified as I. ricinus , a vector of Lyme disease, using MALDI-TOF MS only. Six of the 14 ticks removed from patients were found to be infected by pathogens that included Rickettsia , Anaplasma , and Borrelia spp. MALDI-TOF MS appears to be an effective tool for the rapid identification of tick vectors that requires no previous expertise in tick identification. The benefits for clinicians include the more targeted surveillance of patients for symptoms of potentially transmitted diseases and the ability to make more informed decisions as to whether to administer postexposure prophylactic treatment.

Colistin is currently regarded as one of the 'last-resort' antibiotics used for the treatment of critical infections caused by multidrug-resistant Gram-negative pathogens. Recently, there have been numerous reports of the emergence of a transferable plasmid-mediated colistin resistance gene, mcr-1 in patients, animals, food, and environment. Here, we characterize the support of colistin resistance among environmental isolates collected from seawater of Algiers coast. Our study was carried out on 246 isolates resistant to colistin (MIC > 2 μg/L). The mcr-1 gene was identified in only two isolates; M49 and M78. The two strains were identified as Escherichia coli and were non-susceptible to amoxicillin, ticarcillin, piperacillin, gentamicin, nalidixic acid, tigecycline, tetracycline, trimethoprim-sulfamethoxazole and colistin. For the latter, isolates M49 and M78 showed MIC values of 4 μg/mL and 8 μg/mL, respectively. Only the strain M78 was intermediary resistant to tobramycin. The two E. coli strains belonged to two different sequence types (STs): ST23 for M49 and ST115 for M78. The mcr-1 gene was present on a non-conjugative plasmid in the two strains.

The human body louse is known as a vector for the transmission of three serious diseases—specifically, epidemic typhus, trench fever, and relapsing fever caused by Rickettsia prowazekii, Bartonella quintana, and Borrelia recurrentis, respectively—that have killed millions of people. It is also suspected in the transmission of a fourth pathogen, Yersinia pestis, which is the etiologic agent of plague. To date, human lice belonging to the genus Pediculus have been classified into three mitochondrial clades: A, B, and C. Here, we describe a fourth mitochondrial clade, Clade D, comprising head and body lice. Clade D may be a vector of B. quintana and Y. pestis, which is prevalent in a highly plague-endemic area near the Rethy Health District, Orientale Province, Democratic Republic of the Congo.

Currently, the body louse is the only recognized vector of Bartonella quintana, an organism that causes trench fever. In this work, we investigated the prevalence of this bacterium in human lice in different African countries. We tested 616 head lice and 424 body lice from nine African countries using real-time polymerase chain reaction targeting intergenic spacer region 2 and specific B. quintana genes. Overall, B. quintana DNA was found in 54% and 2% of body and head lice, respectively. Our results also show that there are more body lice positive for B. quintana in poor countries, which was determined by the gross domestic product, than in wealthy areas (228/403 versus 0/21, P < 0.001). A similar finding was obtained for head lice (8/226 versus 2/390, P = 0.007). Our findings suggest that head lice in Africa may be infected by B. quintana when patients live in poor economic conditions and are also exposed to body lice.

Body louse or head louse? Once removed from their environment, body and head lice are indistinguishable. Neither the morphological criteria used since the mid-18th century nor the various genetic studies conducted since the advent of molecular biology tools have allowed body lice and head lice to be differentiated. In this work, using a portion of the Phum_PHUM540560 gene from the body louse, we aimed to develop a multiplex real-time polymerase chain reaction (PCR) assay to differentiate between body and head lice in a single reaction. A total of 142 human lice were collected from mono-infested hosts from 13 countries on five continents. We first identified the louse clade using a cytochrome b (CYTB) PCR sequence alignment. We then aligned a fragment of the Phum_PHUM540560 gene amplified from head and body lice to design-specific TaqMan^© FAM- and VIC-labeled probes. All the analyzed lice were Clade A lice. A total of 22 polymorphisms between the body and head lice were characterized. The multiplex real-time PCR analysis enabled the body and head lice to be distinguished in two hours. This method is simple, with 100% specificity and sensitivity. We confirmed that the Phum_PHUM540560 gene is a useful genetic marker for the study of lice.