Tularemia seroprevalence in humans in the region of the Hittite-Arzawa War (Inner Aegean Region), where the first biological weapon was used 3300 years ago

BACKGROUND

: According to Egyptian records, tularemia emerged in the Canaan region, where it was first identified and spread to Anatolia over the Euphrates. It was used as an active biological weapon for the first time in the Hittite-Arzawa War in 1320-1318 BC. This study aimed to investigate the seroprevalence of tularemia in the Inner Aegean Region, which is thought to be the region where this war was fought 3300 years ago.

METHODS

Tularemia seropositivity in humans was investigated in 27 villages/neighborhoods in 3 districts in each of Manisa, Kütahya, and Uşak provinces. Before the study, the participants were informed about the disease via posters, and their blood samples were taken following filling out the questionnaire. Microagglutination tests were performed using in-house tularemia antigen and V plate for serological experiments. Rose-Bengal test was also performed on seropositive sera.

RESULTS

Of the total of 410 people, 226 (55.12%) were male. The mean age of the volunteers was 43.72 years. The highest participation was from Kütahya Province. According to the results of the tularemia microagglutination test, seropositivity was detected in 6 cases. It was determined that all of the seropositive volunteers were in Kütahya. When the tularemia antibody titers were examined, seropositivity was determined at 1/20-1/160 titers. No positivity was detected in the Rose-Bengal test for cross-reaction.

DISCUSSION

Kütahya has been identified as a risky region in terms of tularemia in the Inner Aegean Region. In order to use the resources in the country economically, first of all, the risk areas in terms of tularemia should be determined by serological studies in all regions. In order to increase awareness about the disease, physicians and filiation teams should be trained in risky areas. Surveillance studies should be conducted to identify and monitor possible sources in areas identified as risky.

Recent Increase in the Prevalence of Fluconazole-Non-susceptible Candida tropicalis Blood Isolates in Turkey: Clinical Implication of Azole-Non-susceptible and Fluconazole Tolerant Phenotypes and Genotyping

Candida tropicalis is the fourth leading cause of candidemia in Turkey. Although C. tropicalis isolates from 1997 to 2017 were characterized as fully susceptible to antifungals, the increasing global prevalence of azole-non-susceptible (ANS) C. tropicalis and the association between high fluconazole tolerance (HFT) and fluconazole therapeutic failure (FTF) prompted us to re-evaluate azole susceptibility of C. tropicalis in Turkey. In this study, 161 C. tropicalis blood isolates from seven clinical centers were identified by ITS rDNA sequencing, genotyped by multilocus microsatellite typing, and tested for susceptibility to five azoles, two echinocandins, and amphotericin B (AMB); antifungal resistance mechanisms were assessed by sequencing of ERG11 and FKS1 genes. The results indicated that C. tropicalis isolates, which belonged to 125 genotypes grouped into 11 clusters, were fully susceptible to echinocandins and AMB; however, 18.6% of them had the ANS phenotype but only two carried the ANS-conferring mutation (Y132F). HFT was recorded in 52 isolates, 10 of which were also ANS. Large proportions of patients infected with ANS and HFT isolates (89 and 40.7%, respectively) showed FTF. Patients infected with azole-susceptible or ANS isolates did not differ in mortality, which, however, was significantly lower for those infected with HFT isolates (P = 0.007). There were significant differences in mortality (P = 0.02), ANS (P = 0.012), and HFT (P = 0.007) among genotype clusters. The alarming increase in the prevalence of C. tropicalis blood isolates with ANS and HFT in Turkey and the notable FTF rate should be a matter of public health concern.

[Microbiological approach to a possible infective endocarditis case caused by Aggregatibacter actinomycetemcomitans]

Aggregatibacter (Actinobacillus) actinomycetemcomitans, a small, gram-negative coccobacillus that grows slow and fastidious, is generally colonized in the oral cavity. It is a rarely seen bacterium because of the difficulty of isolation but it can be a causative agent for dental infections and infective endocarditis (IE) particularly in the persons having prosthetic heart valves. In this report, a possible IE case caused by A.actinomycetemcomitans in a patient with aortic valve replacement has been presented. A 36-year-old man has admitted to Trakya University Hospital, Health Center for Medical Research and Practice, with the complaints of chills, malaise, intermittent fever, severe arthralgia and weight loss (20 kg). During his follow-up period, the blood cultures that were obtained three week intervals yielded the identical gram-negative coccobacilli morphology. The patient was then diagnosed as possible IE on the basis of having one major (growth of the typical microorganisms that may cause IE in two different blood cultures) and two minor (presence of prosthetic valve and high fever) criterias. The isolate could not be identified with conventional methods, while it was identified as Francisella tularensis with VITEK 2 (bioMerieux, France) system. Hence this identification was not confirmed by real-time Taqman polymerase chain reaction, so MALDI-TOF mass spectrometry was used to identify this bacteria. In the first run of the study, the isolate was named as Shigella dysenteriae initially, however when it was retested the next day it was identified as A.actinomycetemcomitans. In order to enlighten these conflicting results, 16S and 23S ribosomal DNA sequence analysis was performed, and consequently the bacterium was identified as A.actinomycetemcomitans. Doxycycline (2 x 100 mg po, 20 days) and streptomycin (2 x 10 mg/kg im, 10 days) therapy were initiated, considering the initial suspicious identification (F.tularensis), and on the fifth day of therapy the blood culture was negative with the regression of patient's complaints. Therapy continued with the addition of rifampicin to doxycycline from the 21(st) day and the patient discharged with cure. As a result, the identification of an exceptional bacterium like A.actinomycetemcomitans may be difficult and time-consuming in certain laboratory facilities. So, the use of different identification methods in addition to classical methods are needed to overcome such a problem, especially for uncommon isolates and clinically discordant cases. This case was presented because A.actinomycetemcomitans is a rare etiological agent for IE patients and it could be a good example to draw attention to the problem when identifying the organism using automatized identification systems.

The antimicrobial susceptibility of Stenotrophomonas maltophilia isolates using three different methods and their genetic relatedness

Background

Stenotrophomonas maltophilia is inherently resistant to many antimicrobials. So far, antimicrobial susceptibility tests for S. maltophilia have not been fully standardized. The purpose of the study was to compare the susceptibility of S. maltophilia isolates against seven different antimicrobials using three different methods and to investigate their genetic relatedness.

Results

Although trimethoprim/sulfamethoxazole (SXT) and ciprofloxacin have the lowest MIC values, SXT (98.1%) and ticarcillin/clavulanate (TLc) (73.1%) were found to be the most effective antimicrobials by agar dilution method, which was in accordance with the breakpoints established by NCCLS. Disc diffusion and E-test was in agreement with agar dilution method for SXT. When the isolation dates, clinics, antibiotyping, and AP-PCR data were investigated, two small outbreaks consisting of five and three cases were determined.

Conclusion

By using the NCCLS criteria, disc diffusion and E-test were unreliable alternative methods for S. maltophilia, except for SXT. However, the significance of these data should be confirmed by further experimental and clinical studies.