ACTA Microbiologica Hellenica (Volume 67, Issue 1)

Acute respiratory tract infections in SARS-CoV-2-negative children during the COVID-19 pandemic

Georgios Meletis1, Styliani Pappa1, Georgia Gioula1, Maria Exindari1, Katerina Haidopoulou2,
Emmanuel Roilides3, Efimia Papadopoulou-Alataki4, Maria Christoforidi1, Anna Papa1
1Department of Microbiology, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki,
National Influenza Laboratory for Northern Greece, Thessaloniki, Greece
22nd Department of Paediatrics, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki,
and AHEPA University General Hospital, Thessaloniki, Greece
33rd Department of Pediatrics, Faculty of Health Sciences, Aristotle University of Thessaloniki, and Hippokration
General Hospital, Thessaloniki, Greece
44th Department of Pediatrics, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki,
Papageorgiou General Hospital Thessaloniki, Greece

During the early stage of coronavirus disease 2019 (COVID-19) pandemic, detection of severe
acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was a priority; however, influenza
viruses and RSV continued to cause seasonal epidemics complicating the diagnostic strategies.
In the present study we estimated the proportion of SARS-CoV-2-negative pediatric
cases attributed to respiratory syncytial virus (RSV) and influenza viruses during a 3-month
period after the identification of the first COVID-19 case in Greece. Ninety SARS-CoV-2-negative
children hospitalized with acute respiratory tract infection were included in the study.
Following a SARS-CoV-2 negative result, the samples were tested by molecular methods for
detection of RSV and influenza viruses. The positive samples were further tested for identification
of the subtype of the viruses. We detected RSV or influenza viruses in 22 (24.4%) samples. Influenza virus was detected in
13 (14.4%) patients (two of type A and 11 of type B), and RSV (all RSV-A) was detected in 9
(10%) patients. In conclusion, a syndromic approach for simultaneous detection of at least influenza virus,
SARS-CoV-2 and RSV will be beneficial for the prompt implementation of appropriate hospital
management including antiviral treatment and isolation measures.

Screening of the antibacterial and anti-biofilm effect of multifloral honey against multidrug-resistant Pseudomonas aeruginosa

Mabrouka Bouacha1, Sana Besnaci
2, Ines Boudiar1, Mohammad Abdulraheem al-Kafaween3
1 Laboratory of Biochemistry and Environmental Toxicology, Department of Biochemistry, Faculty of Sciences,
University of Badji Mokhtar, Annaba, Algeria
2 Laboratory of Cellular Toxicology, Department of Biology, Faculty of Sciences, University of Badji Mokhtar,
Annaba, Algeria
3 Faculty of Pharmacy, Department of Pharmacy, Al-Zaytoonah University ofJordan, Amman,Jordan

In this study, seven Algerian honey samples were assessed for their antibacterial activity on
the growth, viability, and biofilm formation of clinical strains of Pseudomonas aeruginosa isolated from infected wounds. The evaluation of the antibacterial activity of honey samples was
determined by both well assay and micro-broth dilution assay. The effect of honey samples on
the viability of P. aeruginosa was evaluated by a time-kill assay. The anti-biofilm effect was performed by using 96-well plates.
The results revealed that Algerian honey exhibit an antibacterial effect against P. aeruginosa.
The inhibitory diametersranged from 14.97± 3.88mm to 27.98 ± 3.19mm. Minimum inhibitory concentration (MIC) values were in the range of 10 to 40% (w/v). The MIC50 varied from 7.88 %
(w/v) for honey sample 5 to 18.5% (w/v) for honey sample 7 and the MIC90 wassin the range of
18.78 to 38.35% (w/v). The minimum bactericidal concentration (MBC) values ranged from
22.43±6.62% (w/v) to 39.51±8.35% (w/v) and the MBC/MIC ratios were less than 2, indicating
that Algerian honey displayed bactericidal activity on P. aeruginosa strains. In the time-kill curve,
honey samples(1, 2, 3, 4, and 7) destroyed P. aeruginosa after 24 hours of incubation, with honey
samples 5 and 6 destroying the bacterium after 21 hours of incubation. The anti-biofilm effect
revealed that all tested honey samples effectively inhibited biofilm formation with percentages
varying from 54.32% to 97.48%. In conclusion, Algerian honey can be effective as an alternative antibacterial agent for the treatment of infected wounds, especially those caused by P. aeruginosa.

The effects of mammalian hormones in the regulation of growth and virulence in Campylobacter jejuni

Fatma Kalaycı-Yüksek1, Defne Gümüş1, Varol Güler2, Aysun Uyanık-Öcal
1, Mine Anğ-Küçüker1
Istanbul Yeni Yüzyıl University, Faculty of Medicine, Istanbul, TURKEY
1 Department of Medical Microbiology,
2 Department of Medical Biology and Genetics.

Campylobacter jejuni is the most common cause of bacterial food borne disease, but studies on
its pathogenesis are still limited. The effects of various mammalian hormones such as, norepinephrine, epinephrine,serotonin, corticosterone, cortisol and cortisone on growth and different
virulence mechanisms of Campylobacter were reported previously.
In this study, the possible effects of norepinephrine, melatonin, estradiol, progesterone and insulin on growth, adhesion and invasion of C. jejuni were investigated in human adenocarcinoma
colon cell (HT-29) line. Moreover, the alterations on biofilm formation on abiotic surfaces and response to stress conditions were investigated. We also aimed to analyze the effects of hormones
and C. jejuni, together or separately, on viability of human adenocarcinoma colon (HT-29) cells.
Growth alterations were determined spectrophotometrically. Adhesive/invasive bacterial counts were evaluated by colony counting method. Biofilm formation was analyzed using a microtiter
plate assay. The alterations of HT-29 cell viability were determined via methyl thiazolyl diphenyltetrazolium bromide assay.
According to ourresults, growth of C. jejuni was decreased in the presence of hormonesin a dose
and time-dependent manner (p<0.05). Each hormone at all concentrationsreduced the adhesion
of bacteria (p<0.0001). The invasion of C. jejuni was increased in the presence of progesterone
and insulin at all concentrations; which were statistically significant (p<0.0001). The effects of hormones on biofilm formation were variable. Hormones did not affect C. jejuni growth in oxidative and nitrosative conditions(p>0.05). Each hormone and C. jejuni infection have separately decreased the viability of cells after 24 hoursincubation (p<0.005). In 48 hours, viability of cells was
significantly increased in the presence of low-level estradiol (p<0.0001) and high-level progesterone (p<0.0005). The hormones were found to be significantly more effective on viability of infected HT-29 cells than non-infected cells.
In conclusions, these findings once more showed that hormones affect C. jejuni during infectious

Inactivation effect of ultraviolet-C (UVC) irradiation on different microorganisms: Staphylococcus aureus, Bacillus cereus, Escherichia coli and Klebsiella pneumoniae

Taner Bozkurt*1, Fatıma Masume Uslu2
1 Bozkurt Biotechnology R&D ServicesIndustry and Trade Limited Company, Adana, Turkey
2 Department of Biology, Faculty of Science and Letter Cukurova University, Balcali, 01330 Adana, Turkey

Problems caused by increasing multidrug resistance and contamination sources around the
world, as well as major infectious events such as the COVID-19 pandemic, affect the world on
a global scale. For this reason, there is a need to investigate sterilization and disinfection
methods and to develop new environmentally friendly methods with a wide range of implementation capacity. In this study, the effect of ultraviolet-C (UVC) irradiation on different microorganisms wasinvestigated with different application times. In addition,observations were
made about the presence of reactivation in microorganisms with dark and light applications.
Staphylococcus aureus, Bacillus cereus, Escherichia coli, Klebsiella pneumoniae were selected as
test organisms for in vitro experimental studies. When all results were evaluated, it was found that E.coli was most affected by UVC among microorganisms. A direct ratio was determined
between application duration and the lethal effect. These results provide information about
time required for UVC application, which is an environmentally friendly method for killing
these microorganismsresponsible for major infections. In addition, the reactivation properties
of microorganisms were also examined with varying results. It was determined that the number
of reactivated microorganisms were high in the light application compared to the dark application, but for some microorganisms, the reactivation was high at dark application.

Prevalence of acid-resistant Verotoxin-producing Escherichia coli associated with diarrhea

Shamsi S. Shamsi*1, Amira A. Al-Basheer2, Fatima S. Alfage2, Abdelkader A. Elzen2, Khadija M. Ahmad3,4
1 Department of Botany, Research Laboratory, Microbiology Program, Faculty of Science, Sebha University
Sebha, Libya
2 Department of Microbiology, Faculty of Science, Sebha University, Sebha, Libya
3 Department of Microbiology, Faculty of Medicine, Sebha University, Sebha, Libya
4 Department of Microbiology, Sebha Medical Centre, Sebha, Libya

Diarrhea is a significant health issue in many countries, where it is considered one of the prominent causes of morbidity. Escherichia coli is one of the many enteropathogenic bacteria which
causes seasonal diarrhea. This study aimed to look at the prevalence of Verotoxin–producing
E. coli (VTEC) in fecal samples taken from patients with acute diarrhea and their antibiotic resistance profile. A total of 75 strains of E. coli were isolated from fecal samples collected from
patients with acute diarrhea using phenotypic methods. The antibiotic susceptibility pattern of all isolates was determined by the disk agar diffusion method. 57 (90%) VTEC isolates were
confirmed; all VTEC isolates were acid-resistant (pH3). High antibiotic resistance was observed
for cefoxitin (100%), polymyxin B (90%), amoxicillin-clavulanic acid (86%), and tetracycline
(73%). Low resistance levels were observed for chloramphenicol C (18%) and gentamicin CN
(10%). Our results show that strains of E. coli, a major cause of diarrhea, need to be routinely
checked for prevalence of antibiotic resistance.

A case of keratomycosis caused by Curvularia spicifera (previously Bipolaris spicifera) and review of the literature

Eleni Petrou*1, Maria Orfanidou1, Georgios S. Dimtsas2, Maria Moutzouri-Sidiri1, Ioanna Voulgaridi3,Timoleon-Achilleas Vyzantiadis4, Eleni Vagiakou1, Konstantinos Droutsas2
1 Department of Microbiology, General Hospital of Athens “G. Gennimatas”, Mesogeion Av. 154, 11527 Athens, Greece.
2 Department of Ophthalmology, General Hospital of Athens “G. Gennimatas”, Mesogeion Av. 154, 11527 Athens,
3 Department of Microbiology, General Hospital of Trikala, Karditsis 56, 42100 Trikala, Greece.
4 First Department of Microbiology, Medical School, Aristotle University of Thessaloniki, University Campus, 54624
Thessaloniki, Greece.

Fungal keratitisis considered to be an important cause of visual impairment. We present a case
of a-post-injury keratitis in a 29-year old male. Upon admission he presented with decreased
visual acuity and a corneal ulcer. From the corneal tissue culture, Curvularia spicifera (formerly
Bipolaris spicifera) was isolated and the identification was confirmed by molecular methods.
To our knowledge this is the first case of Bipolaris keratomycosis reported in Greece and is indicative of the importance of early diagnosis for a favorable outcome.