Genomic analyses of Francisella tularensis strains confirm disease transmission from drinking water sources, Turkey, 2008, 2009 and 2012

Waterborne epidemics of tularaemia caused by Francisella tularensis are increasingly reported in Turkey. We have used whole genome sequencing to investigate if F. tularensis isolated from patients could be traced back to drinking water sources. Tonsil swabs from 33 patients diagnosed with oropharyngeal tularaemia in three outbreaks and 140 water specimens were analysed. F. tularensis subsp. holarctica was confirmed by microagglutination and PCR in 12 patients and five water specimens. Genomic analysis of three pairs of patient and water isolates from outbreaks in Sivas, Çorum, and Kocaeli showed the isolates to belong to two new clusters of the F. tularensis B.12 genetic clade. The clusters were defined by 19 and 15 single nucleotide polymorphisms (SNPs) in a multiple alignment based on 507 F. tularensis genomes. One synonymous SNP was chosen as a new canonical SNP (canSNP) for each cluster for future use in diagnostic assays. No SNP was identified between the genomes from the patient–water pair of isolates from Kocaeli, one SNP between the pair of isolates from Sivas, whereas the pair from Çorum differed at seven SNPs. These results illustrate the power of whole genome sequencing for tracing F. tularensis patient isolates back to their environmental source.

Evaluation of tularaemia courses: a multicentre study from Turkey

In this multicentre study, which is the largest case series ever reported, we aimed to describe the features of tularaemia to provide detailed information. We retrospectively included 1034 patients from 41 medical centres. Before the definite diagnosis of tularaemia, tonsillitis (n = 653, 63%) and/or pharyngitis (n = 146, 14%) were the most frequent preliminary diagnoses. The most frequent clinical presentations were oropharyngeal (n = 832, 85.3%), glandular (n = 136, 13.1%) and oculoglandular (n = 105, 10.1%) forms. In 987 patients (95.5%), the lymph nodes were reported to be enlarged, most frequently at the cervical chain jugular (n = 599, 58%), submandibular (n = 401, 39%), and periauricular (n = 55, 5%). Ultrasound imaging showed hyperechoic and hypoechoic patterns (59% and 25%, respectively). Granulomatous inflammation was the most frequent histological finding (56%). The patients were previously given antibiotics for 1176 episodes, mostly with β-lactam/β-lactamase inhibitors (n = 793, 76%). Antituberculosis medications were provided in seven (2%) cases. The patients were given rational antibiotics for tularaemia after the start of symptoms, with a mean of 26.8 ± 37.5 days. Treatment failure was considered to have occurred in 495 patients (48%). The most frequent reasons for failure were the production of suppuration in the lymph nodes after the start of treatment (n = 426, 86.1%), the formation of new lymphadenomegalies under treatment (n = 146, 29.5%), and persisting complaints despite 2 weeks of treatment (n = 77, 15.6%). Fine-needle aspiration was performed in 521 patients (50%) as the most frequent drainage method. In conclusion, tularaemia is a long-lasting but curable disease in this part of the world. However, the treatment strategy still needs optimization.

Cervical lymphadenitis: tuberculosis or tularaemia?

Both tuberculosis cervical lymphadenitis (TCL) and oropharyngeal tularaemia (OT) have similar signs, symptoms and pathological findings. We aimed to investigate the frequency of tularaemia antibodies in patients diagnosed with TCL. Using data from the Tuberculosis Control Dispensaries between the years of 2008 and 2011 in Turkey, all patients diagnosed with TCL were informed about and included in the study. Control group subjects were selected from healthy blood donors who lived in the same region. After informed consent was obtained, the sera obtained from volunteer TCL patients and the control group were tested with a microagglutination technique for Francisella tularensis. Antibodies to Brucella were also investigated with a tube agglutination test for cross-reactivity in sera that were seropositive for tularaemia. Sera were obtained from a total of 1170 individuals in the TCL group and 596 in the control group from 67 of 81 provinces in Turkey. Francisella tularensis-positive antibodies were found in 79 (6.75%) cases in the TCL group and two (0.33%) cases in the control group with a titre of ≥1:80 (p < 0.01). When the presence of antibody of any titre was considered, the ratio became 8.2% (96/1170) in the TCL group and 0.67% (4/596) in the control group (p < 0.001). For the first time, with this study, tularaemia serology was found to be positive in a significant portion (6.75%) of diagnosed cases of TCL. In tularaemia endemic regions, it was concluded that tularaemia serology should be investigated in patients suspected of having TCL.

Maternal colonisation with group B streptococcus and effectiveness of a culture-based protocol to prevent early-onset neonatal sepsis

This study was conducted to find out the group B streptococcus colonisation of pregnant women in Kocaeli, Turkey. A culture plus individualised high-risk-based antibiotic prophylaxis was compared with high-risk-based approach alone. The screening of women was performed via vaginal and anal cultures for group B streptococcus (GBS). The maternal GBS colonisation rate was found to be 6.5%. All colonised women or preterm labours with unavailable culture results until delivery received prophylactic antibiotics. Neonatal colonisation rate and early-onset neonatal sepsis due to GBS was 1/200. The unscreened 900 women received prophylactic antibiotics due to a risk factor-based approach. The neonatal colonisation rate was 17/900 (p = 0.1), and the rate of early-onset neonatal sepsis was 3/900 (p = 0.6). A culture plus individualised high-risk-based antibiotic prophylaxis provided an insignificant change in neonatal colonisation and early-onset neonatal sepsis with GBS when compared with high-risk-based approach alone.

Resistance emergence among P. aenrginosa in a rat thigh-abscess model. Comparison of imipenem and meropenem treatment

Resistance emergence to carbapenem antibiotics was studied in a rat-thigh abscess model. Abscesses were developed in three groups with a total of 15 P. aeruginosa strains (three rats per strain). Groups were assigned to imipenem or meropenem treatment while one was left antibiotic-free. Test strains were fully susceptible to these antibiotics and the "Mutant Preventing Concentrations" of imipenem and meropenem over these strains were comparable. Antibiotic serum levels, assessed by serum bioassay test, were similar among therats. After four days, rats (n=45) were sacrificed and carbapenem resistant mutants were selected on imipenem (4 mg/L) and meropenem (4 mg/L) supplemented agar plates. Resistant variants of three strains, from four abscesses, were detected; one in the meropenem group, two in the imipenem and one in the untreated group. The MICs of imipenem and meropenem for the mutants were increased fourfold times or even higher of their counterparts. Resistance emergence under antibiotic pressure in P. aeruginosa has been shown in various conditions. To our knowledge, however, resistance emergence in abscess and also the comparison of imipenem and meropenem in this regard has not been studied before.

Piperacillin with and without tazobactam against extended-spectrum beta-lactamase-producing Pseudomonas aeruginosa in a rat thigh abscess model

BACKGROUND

We compared the antibacterial effect of piperacillin, piperacillin-tazobactam and imipenem in a paired rat thigh abscess model.

METHODS

Two abscesses were provoked in the thighs of rats, one on the right with an extended-spectrum beta-lactamase (OXA-14)-producing Pseudomonas aeruginosa (Ps-162) and the other on the left thigh with a control strain.

RESULTS

The colony counts from the abscesses in log 10 colony-forming units per gram (mean +/- SD) in the imipenem group were 2.78 +/- 1.71 and 3.19 +/- 1.66, in the piperacillin-tazobactam group 4.36 +/- 0.23 and 2.44 +/- 1.97, and in the piperacillin group 4.44 +/- 0.21 and 3.71 +/- 0.99 for Ps-162 and the control strain, respectively. The mean colony counts were significantly different (p < 0.05) between Ps-162 and the control strain in the piperacillin and piperacillin-tazobactam groups.

CONCLUSION

These data showed that piperacillin and piperacillin-tazobactam were significantly less effective against extended-spectrum beta-lactamase-producing P. aeruginosa, while imipenem was equally effective against both Ps-162 and the control strain in this abscess model.

Transient increase in diarrheal diseases after the devastating earthquake in Kocaeli, Turkey: results of an infectious disease surveillance study

Immediately after the devastating earthquake in Turkey in August 1999, an infectious disease surveillance system was established in Kocaeli Province (the biggest area affected). This surveillance study was mainly focused on diarrheal diseases. During a 33-day period, 1,468 stool cultures were processed. Diarrheal diseases increased step-by-step and later decreased to the initial level by the end of this period. Cases were scattered throughout the entire region, and the identified causes were various, indicating a multifocal increase. Of the identified causes, Shigella species were the most common. Nevertheless, Shigella isolates also belonged to distinct serotypes and clones. This study indicated a multifocal, multiclonal increase in diarrheal diseases after this massive disaster, thus indicating the necessity to set up infectious disease surveillance systems after such events.