COVID-19 Antibody Levels among Various Vaccination Groups, One-Year Antibody Follow-Up in Two University Hospitals from Western and Central Turkey

Various clinical outcomes, reinfections, vaccination programs, and antibody responses resulted from the COVID-19 pandemic. This study investigated the time-dependent changes in SARS-CoV-2 antibody responses in infected and/or vaccinated and unvaccinated individuals and to provide insights into spike and nucleocapsid antibodies, which fluctuate during infectious and non-infectious states. This cohort study was carried out at the Ege University Faculty of Medicine hospital in İzmir (western Turkey) and the Erciyes University Faculty of Medicine hospital in Kayseri (central Turkey) between December 2021 and January 2023, which coincided with the second half of COVID-19 pandemic. The study included 100 COVID-19 PCR-positive patients and 190 healthcare workers (HCWs). Antibody levels were followed up via quantitative anti-SARS-CoV-2 spike and qualitative anti-nucleocapsid immunoassays (Elecsys™). Antibody levels declined after infection but persisted for at least 6-8 months. Individuals who had received only CoronaVac had higher anti-nucleocapsid antibody levels in the early months than those who received mixed vaccination. However, anti-spike antibodies persisted longer and at higher levels in individuals who had received mixed vaccinations. This suggests that combining two different vaccine platforms may provide a synergistic effect, resulting in more durable and broad-spectrum immunity against SARS-CoV-2. The study provides information about the vaccination and antibody status of healthcare workers in the second half of the pandemic and provides valuable insights into the dynamics of antibody responses to COVID-19 infection and vaccination.

The efficacy of mesenchymal stem cell treatment and colistin-fosfomycin combination on colistin-resistant Acinetobacter baumannii sepsis model

INTRODUCTION

This study examines the role of mesenchymal stem cells (MSCs) in an experimental sepsis model developed with colistin-resistant Acinetobacter baumannii (CRAB).

MATERIALS AND METHODS

BALB-c mice were divided into treatment groups (MSC, MSC + colistin (C)-fosfomycin (F), and C-F and control groups (positive and negative)). CRAB was administered to mice through intraperitoneal injection. Three hours later, C, F, and MSC were given intraperitoneally to the treatment groups. Colistin administration was repeated every 12 h, F administration was done every 4 h, and the second dose of MSC was administered after 48 h. Mice were sacrificed at 24 and 72 h. The bacterial load was determined as colony-forming units per gram (cfu/g). Histopathological examination was conducted on the left lung, liver, and both kidneys. IL-6 and C-reactive protein (CRP) levels in mouse sera were determined by enzyme-linked immunosorbent assay.

RESULTS

Among the treatment groups, the C-F group had the lowest colony count in the lung (1.24 ± 1.66 cfu/g) and liver (1.03 ± 1.08 cfu/g). The highest bacterial clearance was observed at 72 h compared to 24 h in the MSC-treated groups (p = 0.008). The MSC + C-F group showed the lowest histopathological score in the liver and kidney (p = 0.009). In the negative control group, the IL-6 level at the 24th hour was the lowest (p < 0.001). Among the treatment groups, the CRP level was the lowest in the MSC + C-F group at 24 and 72 h.

CONCLUSION

In a CRAB sepsis model, adding MSCs to a colistin-fosfomycin treatment may be beneficial in terms of reducing bacterial loads and preventing histopathological damage.

[A Marginal Case of Malaria: An Interesting Malaria Story of Cameroon Origin]

Malaria is a serious, contagious infection caused by single-celled parasites. About 200 species of Plasmodium have been described that can cause infection in vertebrates. Five different species of Plasmodium are known to cause infection in humans to date. Infection with more than one type of pathogen is called coinfection. This type of infections can be caused by different species of the same genus, as well as by different species. Malaria coinfections are mostly caused by the combination of Plasmodium vivax and Plasmodium falciparum. In this study, a case of malaria admitted to the hospital and diagnosed was presented. Thin smear blood preparations were prepared from the peripheral blood of a 54 year-old Republic of Türkiye citizen male patient who applied to the emergency department with fever and chills. The preparations were stained with Giemsa and examined under a microscope with a x 100 objective, and trophozoite and gametocyte forms belonging to Plasmodium genus were determined. As a result of probe-based quantitative real-time polymerase chain reaction (qRt-PCR) study with primers specific to Plasmodium vivax, Plasmodium malariae, Plasmodium falciparum, Plasmodium ovale and Plasmodium knowlesi for definitive species identification, co-infection of P.vivax, P.falciparum, P.ovale and P.knowlesi was detected in the patient. In addition, it was proved that our patient was infected with four different species by conventional PCR study in which five species were studied and then by DNA sequence analysis. On the fourth day of artemether-lumefantrine treatment, the patient's fever response was observed and the trophozoite forms disappeared from the third day in the daily peripheral smear follow-up. Since P.vivax and P.ovale species were also detected after species determination by molecular methods, primaquine 1 x 30 mg tablet was added to the existing drugs for the treatment of hypnozoite forms of the parasite. In recent years, there has been an increase in malaria imported cases, especially after visits to African countries. Such rare cases of malaria coinfection may be encountered during visits to geographies located at the intersection of endemic regions. According to the data of the World Health Organization, maximum attention should be paid to the prevention and prophylaxis protocols from vectors, especially in travels to countries with the highest mortality and morbidity. In co-infection cases similar to our patient, for tertian malaria and tertiary ovale malaria, hypnozoid therapy should not be overlooked. When the insecticide-resistant vectors and drug-resistant Plasmodium strains encountered in recent years are evaluated as a whole, there is a need to develop more effective strategies in the fight against malaria. In addition to microscopic examination, which is accepted as the gold standard, we believe that evaluating molecular studies together in diagnosis is extremely important for the treatment process when hypnozoite periods are considered.

[Domestic Malaria Cases in Kayseri Province]

Malaria continues to be a global public health problem considering the number of cases and death rate worldwide. There were no domestic cases reported from our country in the World Health Organization 2021 malaria report. All the 200-250 annual cases reported from our country have a history of travel to the endemic region. In this report, three malaria cases caused by Plasmodium falciparum and Plasmodium vivax in Kayseri province without a history of travel to the endemic region were presented. The first case was an 18-year-old male patient with no known chronic disease. He admitted to the hospital with the complaint of high fever reaching 40°C, which continued for two days, increased with chills and decreased with sweating. Physical examination revealed hepatosplenomegaly and laboratory results revealed thrombocytopenia. Species identification was made by real-time polymerase chain reaction (Rt-PCR) method in the patient with ring-shaped trophozoites in the peripheral smear. Artemether-lumefantrine and primaquine treatments were given to the patient with mixed parasitemia of P.falciparum and P.vivax. One and two days after the admission, the second and third cases also admitted with similar complaints. Mixed parasitemia was observed in all three patients who did not have a history of traveling abroad. After the antiparasitic treatment, the patients improved clinically and laboratory, and no recurrent parasitemia was observed. With the occurrence of these cases, efforts to combat vectors were initiated throughout the province. In conclusion, the presence of anopheles mosquitoes and imported cases still poses a risk for domestic malaria cases. In patients who do not have a history of traveling abroad, malaria should be considered in the clinical preliminary diagnosis and species identification should be made by methods such as Rt-PCR in order to give appropriate treatments.

Real-World Data from Turkey: Is Sofosbuvir/Ledipasvir With or Without Ribavirin Treatment for Chronic Hepatitis C Really Effective?

BACKGROUND

In this study, we aimed to investigate the efficacy and safety of sofosbuvir-based therapies in the treatment of chronic hepatitis C in real-world clinical practice.

METHODS

Data from patients with chronic hepatitis C treated with SOF/LDV ± RBV or SOF/RBV in 31 centers across Turkey between April 1, 2017, and August 31, 2018, were recorded in a nationwide database among infectious disease specialists. Demographics, clinical, and virological outcomes were analyzed.

RESULTS

A total of 552 patients were included in the study. The mean age of the patients was 51.28 ± 14.2, and 293 (55.8%) were female. The majority had HCV genotype 1b infection (65%), 75.04% of the patients underwent treatment, and non-cirrhosis was present at baseline in 381 patients (72.6%). SOF/LDV ± RBV treatment was given to 477 patients and 48 patients received SOF/RBV according to HCV genotype. The total SVR12 rate was 99% in all patients. Five patients experienced disease relapse during the study and all of them were genotype 2. In patients infected with HCV GT2, SVR12 was 77.3%. SVR was 100% in all patients infected with other HCV genotypes. All treatments were well tolerated by patients without causing severe adverse events. Side effects and side effects-associated treatment discontinuation rates were 28.2% and 0.4%, respectively. Weakness (13.7%) was the common side effect.

CONCLUSION

The present real-world data of 525 patients with HCV genotypes 1, 1a, 1b, 3, 4, and 5 who underwent SOF/LDV ± RBV treatment in Turkey demonstrated a high efficacy and safety profile. HCV GT2 patients should be treated with more efficacious treatment.

The Effect of Chronic Diseases, Age and Gender on Morbidity and Mortality of COVID-19 Infection

Background

We aimed to reveal how chronic diseases, age and gender affected morbidity and mortality in patients with Coronavirus disease of 2019 (COVID-19).

Methods

Medical records of all reverse transcription polymerase chain reaction (RT-PCR) positive COVID-19 patients followed up in hospital and home isolation between 13^th of Mar 2020 and 12^th of May 2020 were retrospectively reviewed. The patients were from Kayseri Province, Turkey. Patients' demographic and clinical characteristics and the factors associated with morbidity and mortality were analyzed.

Results

Of all the patients, 773 (95.8%) were alive and 34 (4.24%) died. The fatality rate was 4.2%. There were differences between the age groups in terms of fatality rate (P<0.001). The fatality rate in patients above the age of 65 yr was significantly higher. The fatality rate in the male gender was 2.44 times higher (P<0.05). It was 1.104 times higher in advanced age (P<0.001) and 10.893 times higher in patients with at least one comorbid disease (P<0.05). Hypertension increased mortality by 3.635 times (P<0.05) and chronic pulmonary diseases by 2.926 times (P<0.05).

Conclusion

Advanced age, male gender and accompanying chronic diseases have adverse effects on the course and severity of the disease and hospitalization. They also increased the rate and risk of mortality.

Real-world efficacy, safety, and clinical outcomes of ombitasvir/paritaprevir/ritonavir ± dasabuvir ± ribavirin combination therapy in patients with hepatitis C virus genotype 1 or 4 infection: The Turkey experience experience

BACKGROUND/AIMS

mbitasvir/paritaprevir/ritonavir (OMV/PTV/r) ± dasabuvir (DSV) ± ribavirin (RBV) combination has demonstrated excellent rates of sustained virologic response (SVR) and a very good safety profile in patients with the chronic hepatitis C virus (HCV) genotype 1 or 4 infections. We aimed to investigate the effectiveness and safety of OMV/PTV/r ± DSV ± RBV combination regimen in a real-world clinical practice.

MATERIALS AND METHODS

Data from HCV genotype 1 and 4 patients treated with OMV/PTV/r ± DSV ± RBV (n=862) in 34 centers across Turkey between April 1, 2017 and August 31, 2018 were recorded in a large national database. Demographic, clinical, and virologic data were analyzed.

RESULTS

The mean age of the patients was 55.63, and 430 patients (49.9%) were male. The majority had HCV genotype 1b infection (77.3%), and 66.2% were treatment-naïve. Non-cirrhosis was present at baseline in 789 patients (91.5%). SVR12 rate was 99.1% in all patients. Seven patients had virologic failure. No significant differences were observed in SVR12 according to HCV genotypes. HCV RNA was undetectable at treatment week 4 in 90.9%, at treatment week 8 in 98.5%, and at the end of treatment (EOT) in 98.9%. SVR12 ratio was significantly higher in the non-cirrhotic patients compared to that in the compensated cirrhotic patients. Rates of adverse events (AEs) in the patients was 59.7%.

CONCLUSION

The present real-life data of Turkey for the OBV/PTV/r ± DSV ± RBV treatment of patients with HCV genotype 1b, 1a, or 4 infection from 862 patients demonstrated high efficacy and a safety profile.

[Plasmodium ovale malaria and molecular diagnosis: Could it be a relapse?]

Malaria caused by Plasmodium species continues to affect the half of the world population. According to the World Health Organization 2017 data, 445.000 cases of malaria and 219 million cases of new clinical malaria cases were reported during the year. African continent is the geographical region where the disease is most frequent. In recent years there has been an increase in the number of imported cases after travels to this continent. In this case report, relaps caused by Plasmodium ovale in a male Republic of Turkey citizen patient who has travelled to Uganda only and no other place a year and half ago was presented. Thin blood smear was prepared from the peripheral blood of the patient who admitted to our hospital with complaints of fever and chills. The smear was stained with Giemsa and examined with a x100 objective microscope and trophozoites belonging to Plasmodium genus were detected. Considering the size and locality of the trophozoites in the erythrocytes, it is thought that the parasite may be Plasmodium vivax. Nested PCR method was used for the species identification. Nested PCR studies were performed using Plasmodium genus and specific primers for P.vivax, Plasmodium falciparum, P.ovale and Plasmodium malariae. Nested PCR products were run on gel and P.ovale was visualized in 787 bp region. P.vivax, P.malariae, P.falciparum, P.ovale and Plasmodium knowlesi species specific primers and probe-based quantitative real-time PCR (qRt-PCR) study revealed that the patient was infected with P.ovale. The patient had no history of chronic illness but had a history of recovered malaria 7-8 years ago. The patient did not have any complaints other than these complaints. CMV IgM and IgG and Brucella aglutinisation tests were negative. It is clear that relapse cases can also be seen when P.ovale species are in hypnozoite stage in the liver. Although there are 18 reported cases of relapse in the last century, these phenomena do not provide sufficient evidence for the theory of relapse. A true relapse is thought to be mild symptoms and even subclinical disease. It is also known that it is difficult to distinguish a true recurrence in cases of relapses that can occur after a long time from primer infection. The best way to overcome this difficulty is to assume being in a malaria endemic area or not between primary infection and recurrence. We think that the applications that are carried out together with the microscope and molecular studies, especially in cases where there is relapses in which low parasitemia or travel story are insufficient, are extremely important both in terms of diagnosis and accurate identification of species and in the selection of treatment.

Evaluation of hepatitis B virus transmission and antiviral therapy among hepatitis B surface antigen-positive pregnant women

AIM

The aim of the present study was to assess the potential risk of hepatitis B virus (HBV) vertical transmission among Turkish parturient women and to evaluate the efficacy and safety of antiviral agents.

MATERIAL AND METHODS

Data were collected retrospectively from 114 HBV-infected pregnant women and their infants in eight health institutions in Turkey.

RESULTS

The baseline characteristics of the women were: mean age, 28.3 ± 5.2 years; alanine aminotransferase, 57.4 ± 139.0 U/L; aspartate aminotransferase, 56.6 ± 150.0 U/L; and HBV DNA, 8.3 × 10(7) ± 2.6 × 10(8) copies/mL. Family history of HBV infection was detected in 53.5% (n = 61). In total, 60 (52.6%) pregnant women received tenofovir (60.0%), lamivudine (33.3%) or telbivudine (6.7%) therapy at the median gestational age of 22.2 ± 8.5 (1-36) weeks. All infants were vaccinated and hepatitis B immune globulin was administered, with 81 of them (71.1%) available for follow-up. After completion of HBV vaccination course, 71 (87.7%) infants had protective anti-HBs levels, three (3.7%) were hepatitis B surface antigen-positive, and seven (8.6%) were hepatitis B surface antigen-negative with nonprotective anti-HBs levels. Five of the infants had low gestational birthweight but no other birth defects were observed.

CONCLUSION

According to our results, viral load may not be the only effecting factor for transmission of HBV to children of infected mothers. Pregnant women with high viral load should be followed-up closely during pregnancy. They should begin to take tenofovir or telbivudine, which are category B drugs for pregnancy, at the beginning of the third trimester at the latest. We need new treatment strategies; and close follow-up of mothers and children is another important issue.

Retreatment of Chronic Hepatitis C Infection with Telaprevir: Preliminary Results in Turkey

BACKGROUND

The use of pegylated interferon alpha and ribavirin (PegIFN/RBV) for the retreatment of chronic hepatitis C virus (HCV) infection without a sustained virological response (SVR) prior to PegIFN/RBV treatment has resulted in low success rates.

AIMS

To investigate the efficacy and safety of telaprevir (TVR) in combination with PegIFN/RBV in patients infected with HCV genotypes 1 and 4 who were previously treated with PegIFN/RBV and failed to achieve SVR.

STUDY DESIGN

Multi-center, retrospective, cross-sectional study.

METHODS

The study included 111 patients: 80 prior relapsers, 25 prior null responders, and six prior partial responders to PegIFN/RBV treatment. The patients were given TVR/PegIFN/RBV for 12 weeks, followed by a 12-week PegIFN/RBV treatment; virological response results were assessed at weeks 4, 12, and 24. Treatment was discontinued in patients with HCV RNA >1000 IU/mL at week 4 or with negative RNA results at week 4 but >1000 IU/mL at week 12. Rapid virological response (RVR), early virological response (EVR), extended rapid virological response (eRVR), and virological response at 24th week of treatment were evaluated. The side effects of combination therapy and the rates of treatment discontinuation were investigated.

RESULTS

The mean age of the patients was 56.02±9.96 years and 45.9% were male. Ninety-one percent of the patients were infected with viral genotype 1, 69.6% with the interleukin (IL) 28B genotype CT and 20.2% were cirrhotic. The RVR rate was 86.3% in prior relapsers, 56% in prior null responders, and 50% in prior partial responders (p=0.002). EVR rates in those groups were 91.3%, 56%, and 83.3%, respectively (p<0.001). eRVR rates were 83.8% in prior relapsers, 48% in prior null responders, and 50% in prior partial responders (<0.001). The virological response at the 24th week of treatment was found to be the highest in prior relapsers (88.8%); it was 56% in prior null responders and 66.7% in prior partial responders (p<0.001). Common side effects were fatigue, headache, anorexia, malaise, anemia, pruritus, dry skin, rash, dyspepsia, nausea, pyrexia, stomachache, and anorectal discomfort. All treatments were discontinued due to side effects in 9.9% of patients.

CONCLUSION

High virological response rates were obtained with TVR/PegIFN/RBV treatment. Although side effects were frequently observed, the discontinuation rate of combination therapy was low.

Characterization of the Interleukin-28B Gene rs12979860 C/T Polymorphism in Turkish Chronic Hepatitis C Patients and Healthy Individuals

BACKGROUND

Host genetic factors can affect the progress of hepatitis-C virus (HCV) infection. Interleukin-28B (IL28B) single nucleotide polymorphisms may play an important role in the clearance of HCV spontaneously or with treatment.

AIMS

The aim of our study was to evaluate the rate of IL28B genotypes in patients with Chronic Hepatitis-C (CHC) and healthy control subjects and to examine the characteristics of patients in each IL28B subgroup.

STUDY DESIGN

Case-control study.

METHODS

IL28B polymorphisms were genotyped by Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) in all subjects.

RESULTS

The mean age was 52.3±10.9 years (33% female) in the CHC patients and 52.5±11.5 years (39.1% female) in the healthy controls. The percentage of patients with a high baseline viral load (≥400,000 IU/mL) was higher in the CT group (69.8%) compared to the C/C (44.4%) and T/T (50%) groups (p=0.021). There was no significant difference in liver fibrosis and liver necroinflammation distribution among the CC, CT and TT genotypes with mild, moderate and severe groups (p=0.058 and p=0.791, respectively). Mean age, gender ratio, body mass index, viral load at baseline, rate of HCV genotypes, baseline ALT levels were not significantly different among the three IL28B subgroups (p>0.05). A significant increase was observed in the frequencies of IL28B rs12979860 TT genotypes in the CHC patients (20.6%) compared to the healthy control group (8.7%) (p=0.033).

CONCLUSION

In the patients with chronic HCV-genotype 1b and 4 infections, the IL28B rs12979860 (C>T) gene polymorphism frequency of the TT genotype and T allele was higher than in healthy control subjects. This result indicates that the TT genotype may be more effective in the progression of HCV infection than other genotypes.

Can low-dose preemptive valganciclovir replace standard intravenous ganciclovir treatment in recipients of allogeneic stem cell transplantation?

The aim of this retrospective study was to compare the efficacy and safety of standard intravenous ganciclovir (GCV) with low-dose oral valganciclovir (VGC) in preemptive treatment of cytomegalovirus (CMV) infection in patients who received allogeneic stem cell transplantation (ASCT). Fifty-nine adult ASCT patients with asymptomatic 68 CMV reactivations were included. For preemptive CMV treatment, VGC (900 mg/day) in 44 reactivations or GCV (5 mg/kg twice daily during the first week and once daily afterwards) in 24 CMV reactivations were administered for 21 days. Two consecutive negative results for PCR and/or CMV antigenemia were considered as treatment success. All patients with CMV reactivations were on immunosuppressive treatment. While no positivity was identified in any of the patients who received GCV on day 21, low-titer CMV positivity was noted in three of the patients in the VGC group (P = 0·264). In all three patients, VGC was continued at same dose and no positivity result was detected after 2-3 weeks. Low-grade neutropenia and high grade thrombocytopenia were significantly higher in the GCV group than in the VGC group (P = 0·018 and P = 0·04 respectively). Preemptive strategy of oral low-dose VGC appears preferable to the prevention of CMV disease in ASCT. These results require confirmation in prospective larger clinical studies.

Lamivudine resistance mutations in patients infected with hepatitis B virus genotype D

AIM: To determine the distribution of viral genotypes for primary or acquired lamivudine resistance.

METHODS: A total of 283 patients with chronic hepatitis B virus (HBV) infection (245 patients with chronic hepatitis B and 38 inactive hepatitis B surface antigen carriers) were included in the study. The HBV genotype was determined by using quantitative real-time polymerase chain reaction and sequence analysis, and tyrosine-methionine-aspartate-aspartate (YMDD) motif mutations were determined using the reverse transcriptase hybridization method.

RESULTS: Lamivudine resistance was determined in a total of 25 (10.7%) chronic hepatitis B patients. Eight subjects (4%) had primary resistance to lamivudine, and 17 (53.1%) had secondary resistance to lamivudine. Genotype D, which was isolated from 267 of the patients with chronic HBV infection, was the dominant genotype in Turkey.

CONCLUSION: Identification of YMDD motif mutations should have a positive impact on the selection of proper antiviral medication for patients, even for those who are nucleoside naïve.

Microbiologically documented infections following peripheral blood stem cell transplantation: single center experience

This study was performed to assess the incidence of infectious complications in patients undergoing autologous and allogeneic hematopoietic stem cell transplantation (HSCT). The characteristics of microbiologically documented infections in 114 consecutive patients undergoing HSCT (84 autologous, 30 allogeneic) were analyzed. Conditioning and the pre-engraftment period until one month was defined as the early period; the post-engraftment period until one year was defined as the late period. All patients received antibiotic prophylaxis and hematopoietic growth factors during neutropenia. Febrile patients received imipenem-cilastatin or cefepime plus amikacin or ceftazidime plus amikacin. A total of 117 episodes with microbiologically documented infections were seen 90 of 114 patients and 79% of the patients experienced at least one febrile episode during their post-transplant course. Of these episodes, 69 (59%) were in the early period and 48 (41%) were in the late period. In the early period, 38.8% of causative organisms were gram-positive, 51.5% were gramnegative and 7.7% were fungi. The most common pathogens were coagulase-negative Staphylococcus (CoNS) and E. coli in the early period. In the late period, 44.6% of causative organisms were gram-positive, 44.6% were gram-negative and 6.8% were fungi. CoNS and E. coli were also the most commonly isolated agents in this period. Resistance to methicillin was detected in 47.4% of S. aureus and 86.5% of CoNS isolates. The isolation rate was in accordance with previous reports; similar percentages of gram-positive and gram-negative isolates were found in patients undergoing HSCT in both periods. However, a remarkably low rate of viridans streptococci and fungi were observed. The spectrum of pathogens detected in these cases serves as the basis for recommendations on the choice of empiric antimicrobial treatment regimens. Therefore, studies reporting local microbiological findings are necessary. We suggest that local microbiologic surveillance should be known before empiric antimicrobial therapy is started in each institution.

Incidence, risk factors and mortality of nosocomial pneumonia in intensive care units: a prospective study

To determine the frequency, risk factors and mortality of nosocomial pneumonia a prospective study was conducted in the intensive care units. In the study period, 2402 patients were included. The nosocomial pneumonia was defined according to the Centers for Disease Control Criteria. Overall, 163 (6.8%) of the patients developed nosocomial pneumonia and 75.5% (n = 123) of all patients with nosocomial pneumonia were ventilator-associated pneumonia. 163 patients who were admitted to the intensive care unit during the same period but had no bacteriologic or histologic evidence of pneumonia were used as a control group. The APACHE II score, coma, hypoalbuminemia, mechanical ventilation, tracheotomy, presence of nasogastric tube were found as independent risk factors. Crude and attributable mortality were 65% and 52.6%, respectively. The mortality rate was five times greater in the cases (OR: 5.2; CI 95%: 3.2–8.3). The mean length of stay in the intensive care unit and hospital in the cases were longer than controls (p < 0.0001). Patients requiring mechanical ventilation have a high frequency of nosocomial pneumonia.