Molecular characterization and antimicrobial susceptibility of methicillin-resistant staphylococcus aureus isolates from clinical samples and asymptomatic nasal carriers in Istanbul (Turkey)

Background

Methicillin-resistant Staphylococcus aureus (MRSA) has been a widespread problem in Turkish hospitals.

Aims

The aim of this study was to investigate the staphylococcal toxin genes of the clinical and nasal MRSA isolates, and their antibiotic resistance profiles.

Materials and Methods

Isolation of nasal and clinical bacteria was done following standard microbiological methods. The presence of antimicrobial resistance genes (mec A, pvl, tsst-1, and SEs genes) was determined using the real-time polymerase chain reaction (PCR) assay.

Results

Among nasal MRSA isolates, 66.7% were toxigenic. The distribution of genes was as follows: pvl 26.7%, tsst-1 3.3%, and SEs 36.7%. Therefore, the nasal MRSA isolates had a rate of 23.3% multidrug resistance (MDR) pattern to the non-beta-lactams antibiotics. All (100%) clinical MRSA isolates were found to be toxigenic. The distribution of genes was as follows; pvl 10%, tsst-1 6.7%, and SEs 100%. The clinical MRSA isolates had a rate of 60% MDR.

Conclusions

Following detection of pvl, tsst-1, and SEs among nasal and clinical MRSA isolates, and the presence of high antimicrobial resistance, the spread of these strains may be an additional factor contributing to the emergence of community-acquired (CA)-MRSA and hospital-acquired (HA)-MRSA. This study is the first to determine the resistance to linezolid and tigecycline in both nasal and clinical MRSA isolates, for the first time in Turkey. All nasal and clinical MRSA isolates were uniformly susceptible to vancomycin and quinupristin-dalfopristin. Our findings show that MRSA infections in Turkey can be empirically treated with vancomycin and quinupristin-dalfopristin based on the lack of demonstrable resistance to these drugs.

Presence of vancomycin, aminoglycosides, and erythromycin resistance genes in enterococci isolated from clinical samples in Turkey

BACKGROUND

Emergence of high-level aminoglycoside and glycopeptide resistance causes more severe prognosis, higher mortality, and recurrence in enterococcal infections. The present study was conducted to investigate the antimicrobial resistance patterns, prevalence of AMEs, erm and van genes of enterococci isolated from various clinical samples at Istanbul University, Cerrahpasa Medical School hospital.

METHODS

During the period of 2012-2013, a total of 128 enterococcal isolates collected from various clinical samples were typed with the API 20 strep test, and antibiotic sensibilities were analysed with the disc diffusion and E-test methods. The detection of resistant genes was determined by a multiplex PCR method.

RESULTS

Forty-nine percent E. faecalis, 46% E. faecium, 4 E. avium and 2 E. durans were detected. E. faecium resistance rates were significantly higher than E. faecalis (p < 0.001). The resistant genes were analysed in 50 enterococcus strains. The vanA gene was found in 29 of the 30 VRE strains. The most prevalent AMEs genes were aac (6')-Ie-aph (2")-Ia gene (72%), followed by aph (3')-IIIa gene (30%). The ermB gene was found in 49 of a total of 50 strains.

CONCLUSIONS

This study shows that aac (6')-Ie-aph (2")-Ia, ermB, and vanA genes are common among enterococci isolates in our hospital and spread of VRE along with acquisition of resistance to most of the antibiotics used in therapy.

An in Vitro Experimental Study on the Antimicrobial Activity of Silicone Oil against Anaerobic Bacteria

PURPOSE

To investigate the in vitro antimicrobial activity of silicone oil against anaerobic agents, specifically Propionibacterium acnes, Peptostreptococcus spp., Peptostreptococcus anaerobius, Bacteroides fragilis, Fuobacterium spp., and Clostridium tertium.

METHOD

A 0.5 McFarland turbidity of Propionibacterium acnes, Peptostreptococcus spp., Peptostreptococcus anaerobius, Bacteroides fragilis, Fuobacterium spp., and Clostridium tertium was prepared, and 0.1 mL was inoculated into 0.9 mL of silicone oil. Control inoculations were performed in anaerobic blood agar and fluid thioglycollate medium without silicone oil.

RESULTS

Propionibacterium acnes retained their viability on the 3rd day in the presence of silicone oil. In total, 9.7 × 10(6) colonies were enumerated from 1 mL of silicone oil. After a prolonged incubation of 7 days, the number of colonies observed was 9.2 × 10(6). The other bacteria disappeared after the 3rd day of incubation in silicone oil.

CONCLUSIONS

Propionibacterium acnes, which is the most common chronic postoperative endophthalmitis agent, is thought to be resistant to silicone oil.

The relationship between bifidobacteria and allergic asthma and/or allergic dermatitis: a prospective study of 0-3 years-old children in Turkey

Bifidobacteria are beneficial bacteria for humans. These bacteria are particularly effective at protecting against infectious diseases and modulating the immune response. It was shown that in newborns, the fecal distribution of the colonizing Bifidobacterium species influences the prevalence of allergic diseases. This study aimed to compare the faecal Bifidobacterium species of allergic children to those of healthy children to detect species level differences in faecal distribution. Stool samples were obtained from 99 children between 0 and 3 years of age whose clinical symptoms and laboratory reports were compatible with atopic dermatitis and allergic asthma. Samples were also obtained from 102 healthy children who were similar to the case group with respect to age and sex. Bifidobacteria were isolated by culture and identified at the genus level by API 20 A. In addition, 7 unique species-specific primers were used for the molecular characterization of bifidobacteria. The McNemar test was used for statistical analyses, and p < 0.05 was accepted as significant. Bifidobacterium longum was detected in 11 (11.1%) of the allergic children and in 31 (30.3%) of the healthy children. Statistical analysis revealed a significant difference in the prevalence of B. longum between these two groups (X(2): 11.2, p < 0.001). However, no significant differences in the prevalence of other Bifidobacterium species were found between faecal samples from healthy and allergic children. (p > 0.05). The significant difference in the isolation of B. longum from our study groups suggests that this species favors the host by preventing the development of asthma and allergic dermatitis. Based on these results, we propose that the production of probiotics in accordance with country-specific Bifidobacterium species densities would improve public health. Thus, country-specific prospective case-control studies that collect broad data sets are needed.

The diagnostic value of Western blot method in patients with cystic echinococcosis

Cystic echinococcosis (CE) is the larval cystic stage (called echinococcal cysts) of a small taeniid-type tapeworm (Echinococcus granulosus). Carnivores such as dogs are usually definitive hosts. Intermediate hosts are typically herbivores such as sheep and cattle. CE can be detected using various imaging techniques such as ultrasonography or radiology. Moreover the primary diagnosis has to be confirmed by serological tests since the clinical signs of the disease are non-specific. This study examined the antigenic band patterns useful for serologic diagnosis of hydatidosis. We also report on the post-operative evolution of patients treated for this disease and also determined the diagnostic performance of Western blot IgG kit. Twenty-five (16 females and 9 males) non-operated patients with hydatid cysts (NOP) and 33 (21 females and 12 males) operated patients with hydatid cysts (OP) were included as study group and 22 healthy individuals (14 females and 8 males) with no known chronic diseases were included as a control group. The ages of the patients and control group individuals were between 16-83 years. Patient and control groups were matched for age and sex. Cyst hydatid IgG antibodies were detected in the sera from all patient groups but no antibodies were found in the sera from the control group using ELISA IgG method. Twenty-three (92%) non-operated patients and 18 (54.5%) operated patients exhibited positive results when Western blot IgG kit was used. The P7 band pattern was detected in the sera from all operated and non-operated patients. Twenty-seven of these positive cases had p7 and (p7+p16/18), (p7+p24/26) or (p7+p16/18+p24/26). No antibodies against p7, p16/18 ve p24/26 band patterns were seen in sera from the control group A statistically significant difference was detected between operated and nonoperated patients for Western blot positivity.(p<0.01). p: 0.018- X2=5,604- OR: 0.176- 95% CI: 0.037- 0.841. The sensitivity, specificity, positive prediction and negative prediction values of Echinococcus granulosus Western blot kit for 25 cases with CE and 22 healthy controls were calculated as 92%, 100%, 100% and 91.7%, respectively. In conclusion, we suggest that monitoring p7 in all non-operated patients may be useful to determine the efficiacy of medical treatment and that monitoring p7 antibodies using serological and Western blot methods in operated patients may be useful for the screening of post-operative evolution in patients with hydatid cyst.

The role of latent toxoplasmosis in the aetiopathogenesis of schizophrenia--the risk factor or an indication of a contact with cat?

We assessed IgG antibody to Toxoplasma gondii in 300 inpatients with schizophrenia (SG), 150 outpatients with anxiety and depressive disorders (PCG), and 150 healthy blood donors (HCG). Seropositivity rates were 60.7% for SG, 36.7% for PCG, and 45.3% for HCG (p<0.001). The seropositivity rate for anti-Toxoplasma IgG antibodies in SG was significantly higher that in PCG (chi2 = 23.11, OR = 2.66, p = 0.001) and HCG (chi2 = 9.52, OR = 1.86, p = 0.002). Among SG, 85% of those who reported close cat contact had IgG antibodies to T. gondii. Close cat contacts were reported by 59% of SG, 6% of PCG, and 9% of HCG (p<0.001). There was a nonsignificant positive association between toxoplasmosis and schizophrenia for people with a contact with a cat (OR = 2.221, p = 0.127, CI95 = 0.796-6.192), and significant negative association between toxoplasmosis and schizophrenia for people without contact with a cat (OR = 0.532, p = 0.009, CI95 = 0.332-0.854). Close cat contact (OR = 2.679, p<0.001), 51-65-year age group (OR = 1.703, p<0.001) and education [illiterate+primary (OR = 6.146, p<0.001) and high school (OR = 1.974, p = 0.023)] were detected as independent risk factors in multivariate logistic regression. The effect of toxoplasmosis on risk of schizophrenia disappeared in the complex model analyzed with multivariate logistic regression. In conclusion, our data suggest that the toxoplasmosis has no direct effect on the risk of schizophrenia in Turkey but is just an indication of previous contacts with a cat.

Aneurysm and Helicobacter pylori relationship: the seropositivity of CagA, VacA and other antigens of Helicobacter pylori in abdominal and ascending aortic aneurysms

Helicobacter pylori is thought to be related to atherosclerosis and aneurysm development. We aimed to detect virulance factors of H. pylori and examine the potential etiopathogenetic relationship between aortic aneurysm and H. pylori, 58 abdominal aortic aneurysm (AAA) and 38 ascending aortic aneurysm (AsAA) cases and 57 Healty control group (HCG) were included. We investigated H. pylori IgG by ELISA and virulance factors by Western-Blot (WB) method. No difference was found between AAA (67.24%), AsAA (73.68%) and HCG (57.89%) for H. pylori IgG (p > 0.05). A significant difference was found between AsAA (78.95%) and HCG (57.89%) for H.pylori IgG (p < 0.05) by ELISA and a significant difference was found only between AsAA (100%) and HCG (37.5%) for H. pylori IgG in the 45-55 age group by WB. A statistically significant difference was found between AAA and AsAA for VacA and CagA + VacA and CagA + VacA + UreA antigens and also a significant difference was found between AsAA and HCG for CagA + UreA antigens (p < 0.05). Finally, we suggest that H. pylori VacA has a more important role than CagA in the development of two aneurysms especially in ruptured AAA. New extended studies detecting H. pylori DNA are needed to detect the aetiopathogenesis between aneurysm types and H. pylori.

Oropharyngeal flora changes after tonsillectomy

Objective: We aimed to investigate the effect of tonsillectomy on oropharyngeal flora in children who underwent tonsillectomy for chronic recurrent tonsillitis.

Study Design and Setting: A prospective study was performed comprising patients with chronic recurrent tonsillitis who underwent tonsillectomy at the Department of Otolaryngology, Cerrahpasa Medical School. Incisional core biopsies of excised tonsils were also performed. Swabs and core biopsy specimens were transferred and maintained in Stuart's medium and sent to the Department of Microbiology and Clinical Microbiology at Cerrahpasa Medical School for microbiologic evaluation.

Subjects and Methods: Oropharyngeal swabs and tonsillar core biopsy specimens from 31 patients operated on for recurrent tonsillitis were cultured. Follow-up oropharyngeal swabs were cultured one month after tonsillectomy.

Results: There was no significant difference between the preoperative and postoperative isolation rate of the potentially pathogenic bacteria. Normal aerobic flora did not change significantly. However, the isolation rate of the Neisseria species dropped ( P = 0.097) but did not reach statistical significance. Among anaerobes, Bacteroides fragilis, one of the major anaerobic bacteria, dropped significantly ( P = 0.007). The Propionibacterium acnes isolation rate increased significantly ( P = 0.009).

Conclusion: Oropharyngeal anaerobic bacterial flora decreases after tonsillectomy in recurrent tonsillitis patients. The isolation rate for bacteria of the normal flora and potentially pathogenic bacteria does not change. Tonsils with recurrent infections may become a nidus for anaerobic bacteria. In patients with chronic recurrent tonsillitis, tonsillectomy may help change anaerobic bacterial oropharyngeal flora to the normal flora found in healthy individuals.

Microbial changes in conjunctival flora with 30-day continuous-wear silicone hydrogel contact lenses

PURPOSE

To determine the effect of 30-day continuous-wear silicone hydrogel contact lenses on the conjunctival flora in asymptomatic wearers.

METHODS

The authors studied 29 eyes of 15 patients wearing Focus NIGHT & DAY silicone hydrogel contact lenses for up to 30 nights of continuous wear. The average age of the patients was 25.54 +/- 8.98 years. Cultures of the inferior cul-de-sac were taken bilaterally from all eyes, before and after lens wear in asymptomatic patients. The isolation and identification of bacteria were made by standard clinical laboratory methods.

RESULTS

The number of eyes whose conjunctival cultures were sterile before using the lenses significantly decreased (P = 0.0005), and the number of eyes with a growth of coagulase-negative staphylococci and diphtheroid rods in their conjunctival cultures significantly increased after using these lenses (P = 0.001 and P = 0.031, respectively). Conversely, a statistically significant difference was not found in the number of eyes that carried Propionibacterium acnes and Fusobacterium nucleatum in their conjunctival cultures before and after using the 30-day continuous-wear silicone hydrogel lenses (P = 0.998 and P = 0.488, respectively).

CONCLUSIONS

The results suggest that the sterility of the conjunctiva significantly decreased after using 30-day continuous-wear silicone hydrogel contact lenses. In addition, the number of bacteria of the normal conjunctival flora significantly increased after the use of these lenses. Contamination by the bacteria of the eyelids may be a possible colonization factor in this study group. Therefore, it is appropriate to examine the patients who wear these lenses more frequently.

Antimicrobial resistance and beta-lactamase production of clinical isolates of prevotella and porphyromonas species

BACKGROUND

This study determined the beta-lactamase production and the antimicrobial resistance of 72 Prevotella species and 48 Porphyromonas species isolated from different clinical specimens.

METHODS

All strains were identified using API 32 ID. The beta-lactamase production was determined by nitrocefin disks. E test strips of benzylpenicillin, ampicillin + sulbactam, cefoxitin, clindamycin, metronidazole and imipenem were tested for each strain.

RESULTS

Nineteen Prevotella melaninogenica, 18 Prevotella intermedia, 16 Prevotella denticola, 11 Prevotella loescheii and 8 Prevotella bivia strains were identified. Four were clindamycin resistant. The highest beta-lactamase production was found at a rate of 68.4% in P. melaninogenica species. Additionally, 33 Porphyromonas asaccharolytica and 15 Porphyromonas gingivalis strains were identified. None of them produced beta-lactamase.

CONCLUSION

In view of the emerging antibiotic resistance among anaerobes, the current local susceptibility profile of our Prevotella and Porphyromonas species will establish the basis for additional surveys tracing significant changes in the antimicrobial resistance of our clinical isolates.

Microbiologic evaluation of frequent-replacement soft contact lenses

PURPOSE

This article reports a microbiologic study of two kinds of monthly frequent-replacement daily wear soft contact lenses, with different amounts of water content, in asymptomatic contact lens wearers.

METHOD

We studied 35 lenses of 18 patients who wear frequent-replacement soft contact lenses with a water content of 38% and 40 lenses of 20 patients using frequent-replacement contact lenses with a water content of 55%. The lenses worn by patients regularly for 1 month were removed from their eyes in a sterile manner on the 30th day and were studied microbiologically to isolate pathogenic agents.

RESULTS

In the group of monthly frequent-replacement soft contact lenses with a water content of 38%, microorganisms were isolated at a rate of 91%; and in the group of monthly frequent-replacement soft contact lenses with a water content of 55%, microorganisms were isolated at a rate of 85%. When the two groups were compared, there was no statistically significant difference (P=0.31). Although coagulase-negative staphylococci, Corynebacterium spp, and gram-negative rods were detected in both groups, Staphylococcus aureus, non-hemolytic streptococci, Neisseriae spp, and Penicillium spp also were isolated in the group with the higher water content.

CONCLUSION

Bacteria spreading from the environment or from skin flora to the eyes showed more diversity in the group of frequent-replacement soft contact lenses with a high water content. Additionally, Penicillium spp also was isolated in this group. Therefore scrupulous attention to daily lens care is crucial for people who wear frequent-replacement soft contact lenses.

Incidence of H. influenzae in a day-care center

In this study nasopharyngeal haemophilus influenzae flora of healthy children in a day-care center in istanbul were analyzed. Nasopharyngeal cultures of 168 children between two and five years of age were obtained between December 1, 1992 and April 1, 1993 and investigated. H. influenzae was isolated in 104 cultures. H. influenzae type b (Hib), type f and H. parainfluenzae were found 87 children (51.8%), 15 children (8.9%) and one child (0.6%), respectively, while non-typable H. influenzae was discovered in one child (0.6%). Hib, which is the cause of invasive H. influenzae infection in childhood, was evaluated with respect to age; its incidence was found to be highest in two and three-year-old children, and reduced in children older than four years of age. Although Hib was seen in 518 percent of normal children in the day-care center, invasive Hib disease was not seen in any of those children. Therefore, these children have considered carrier of Hib without clinical manifestations.