2015, Cilt 45, Sayı 1, Sayfa(lar) 022-029 |
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Investigation of BK and JC Virus DNA Positivities by Real-Time Polymerase Chain Reaction in Immunosuppressive Patients |
İmran SAĞLIK1, Derya MUTLU1, Gözde ÖNGÜT1, Sevtap VELİPAŞAOĞLU GÜNEY2, Dilara ÖĞÜNÇ1, Dilek ÇOLAK |
1Akdeniz Üniversitesi Tıp Fakültesi, Tıbbi Mikrobiyoloji Anabilim Dalı, Antalya 2Akdeniz Üniversitesi Tıp Fakültesi, Çocuk Sağlığı ve Hastalıkları Anabilim Dalı, Antalya |
Keywords: Lower respiratory tract infections, direct fluorescent antibody test, cell culture, RSV |
Objective: Respiratory syncytial virus (RSV) is the most common cause of
lower respiratory tract infections (LRTI) in children. This study was aimed
to investigate the presence of RSV by cell culture and direct fluorescent
antibody (DFA) methods in children with LRTI and to evaluate the results in
association with the clinical findings of the patients.
Materials and Methods: The study included 162 children with LRTI. The
age group of the cases was 0-5 years old, of which 107 were outpatients and
55 were inpatients. Nasopharyngeal swab samples were obtained by flocked
swabs and transported to the laboratory within the viral transport medium
(Copan Diagnostics, Brescia, Italy). Samples were inoculated into the shell-vial
cell culture prepared with A549 cells and presence of RSV were investigated
in the fixed cells by fluorescence-labeled monoclonal antibodies (Anti-RSV
Group FITC, Argene, BioMérieux, France) after 48-72 hours of incubation.
For the DFA method, slides were prepared directly from the samples with
cytospin centrifuge method and RSV was investigated following staining
with fluorescent labeled monoclonal antibodies in a similar way. Samples
which yielded discordant results with cell culture and DFA test, RSV RNA
was investigated by a commercial real-time polymerase chain reaction
(RT-PCR) kit (RealStar RSV RT-PCR Kit, Altona Diagnostics, Germany). In
addition, symptoms, physical examination and laboratory findings together
with the treatment outcome of the patients were recorded.
Results: RSV was detected in 26.5% (43/162) of the samples by cell culture.
Both cell culture and DFA detected RSV in 24.3% (38/162) of the samples
while 71.0% (115/162) were negative with both tests. Five RSV cell culture
positive samples were negative with DFA, and four positive samples with
DFA were negative with cell culture. In these nine samples, the RSV PCR test
results were consistent with the cell culture test results. When the cell culture
method was considered as the reference method, sensitivity, specificity,
positive (PPV) and negative predictive values (NPV) for the DFA method
were 88.4%, 96.6%, 90.5% and 95.8%, respectively. The average age of the
RSV-positive patients (11.2±11.3 months) were significantly lower than that
of RSV-negative patients (21.7±18.6 months) (p=0.001). There were no
significant difference in terms of gender, symptoms, physical examination,
treatment outcome and other laboratory markers (CRP, leukocytosis, increase
in neutrophile count, lymphocytosis and thrombocytosis) between RSV
positive and negative patients (for all p>0.05). The analysis of the RSV test
requests revealed that 93.8% of the requests were in January, February and
March, and all positive cases were detected in these months.
Conclusion: In conclusion, RSV was detected in 26.5% of 0-5 years old
children with LRTI and this rate was significantly higher in early ages. DFA
method which has a high sensitivity and specificity in the diagnosis of RSV
infection, ensures rapid diagnosis and enables the evaluation of the quality
of respiratory samples.
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