Marek Juda

A comparative analysis of phenotypic and genotypic methods for the determination of the biofilm-forming abilities of Staphylococcus epidermidis

The collection of 146 Staphylococcus epidermidis strains isolated from the nasopharynx of lung cancer patients has been studied for the ability of slime secretion and biofilm formation using the Congo red agar (CRA) test and the microtiter plate (MtP) method, respectively. The prevalence of the icaAD and the aap genes was also analyzed. Some isolates (35.6%) were biofilm positive by the MtP method, while 58.9% of isolates exhibited a slime-positive phenotype by the CRA test. The sensitivities of the CRA test evaluated using the MtP method as a gold standard of biofilm production were 73.1%, 97.3% and 13.3% for all the strains screened, ica-positive and ica-negative strains, respectively. The genotype ica(+)aap(+) was correlated with a strong biofilm-producer phenotype. Interestingly, some of the ica(-)aap(-) isolates could also form a biofilm. The correlation between the presence of icaAD genes and the biofilm-positive phenotype by the MtP method as well as slime production by the CRA test was statistically significant (P<0.0001). However, some S. epidermidis strains possess the potential ability of ica-independent biofilm formation; thus, further studies are needed to determine reliable, short-time criteria for an in vitro assessment of biofilm production by staphylococci.

The prevalence of genotypes that determine resistance to macrolides, lincosamides, and streptogramins B compared with spiramycin susceptibility among erythromycin-resistant Staphylococcus epidermidis

Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, can be regarded as potential reservoirs of resistance genes for pathogenic strains, e.g., Staphylococcus aureus. The aim of this study was to assess the prevalence of different resistance phenotypes to macrolide, lincosamide, and streptogramins B (MLSB) antibiotics among erythromycin-resistant S. epidermidis, together with the evaluation of genes promoting the following different types of MLSB resistance:ermA, ermB, ermC,msrA, mphC, and linA/A’. Susceptibility to spiramycin was also examined. Among 75 erythromycin-resistantS. epidermidis isolates, the most frequent phenotypes were macrolides and streptogramins B (MSB) and constitutive MLSB (cMLSB). Moreover, all strains with the cMLSB phenotype and the majority of inducible MLSB (iMLSB) isolates were resistant to spiramycin, whereas strains with the MSB phenotype were sensitive to this antibiotic. The D-shape zone of inhibition around the clindamycin disc near the spiramycin disc was found for some spiramycin-resistant strains with the iMLSB phenotype, suggesting an induction of resistance to clindamycin by this 16-membered macrolide. The most frequently isolated gene was ermC, irrespective of the MLSB resistance phenotype, whereas the most often noted gene combination wasermC, mphC, linA/A’. The results obtained showed that the genes responsible for different mechanisms of MLSB resistance in S. epidermidis generally coexist, often without the phenotypic expression of each of them.

Empirical validation of Polish guidelines for the management of acute streptococcal pharyngitis in children

OBJECTIVE Group A Streptococcus (GAS) pharyngitis is currently the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Polish guidelines advocate the use of modified Centor score (MCS) to assess the probability of GAS pharyngitis. They advise performing throat culture or rapid antigen detection test (RADT) in children with score 2-3 in MCS and treating with antibiotic only those in whom GAS was detected. Negative RADT results should be confirmed by culture. In children with score 4, the guidelines allow to introduce empiric antibiotic therapy. Phenoxymethyl penicillin is recommended as a drug of choice to treat GAS pharyngitis. The aim of our study was to evaluate the accuracy of strategy recommended by Polish guidelines in identifying those children with acute pharyngitis who require antibiotic treatment. Hence, diagnostic values of score 4 in MCS and RADT were assessed using throat culture as a reference standard. Phenoxymethyl penicillin efficacy in GAS eradication and prevention of post-streptococcal complications were estimated as well. METHODS Ninety children between 2 and 15 years of age with acute pharyngitis symptoms suggesting GAS etiology (MCS ≥ 2), participated in our study. At the initial visit MCS was evaluated and two throat swabs were collected to perform RADT and culture. In children with GAS pharyngitis treated with penicillin, microbiological cure was assessed by performing two control throat cultures. Next, children were under observation for 3 months. RESULTS Positive predictive value of score 4 in MCS turned out to be 48.05% (95% CI: 36.5-59.7%). RADT sensitivity, specificity and diagnostic accuracy proved to be 100%, 96%, and 98%, respectively. GAS eradication rate in children treated with penicillin turned out to be 92.5%. No post-streptococcal sequelae occurred in any child in 3-month observation. CONCLUSIONS Empiric antibiotic therapy in children with score 4 in MCS will result in significant overtreatment of those with nonstreptococcal pharyngitis. New generation RADT diagnostic value in GAS detection proved to be equivalent to that of culture, which obviates the need of backup culture in children with negative RADT results. Phenoxymethyl penicillin revealed high eradication efficacy and proved to prevent post-streptococcal sequelae in children with acute GAS pharyngitis.

The preliminary study of prebiotic potential of Polish wild mushroom polysaccharides: the stimulation effect on Lactobacillus strains growth

PurposeAccording to the vast body of evidence demonstrating that the intestinal microbiota is undoubtedly linked with overall health, including cancer risk, searching for functional foods and novel prebiotic influencing on beneficial bacteria is necessary. The present study aimed to investigate the potential of polysaccharides from 53 wild-growing mushrooms to stimulate the growth of Lactobacillus acidophilus and Lactobacillus rhamnosus and to determine the digestibility of polysaccharide fractions.MethodsMushroom polysaccharides were precipitated with ethanol from aqueous extracts. Determination of growth promoting activity of polysaccharides was performed in U-shaped 96-plates in an ELISA reader in relation to the reference strain of L. acidophilus and two clinical strains of L. rhamnosus. The digestibility of mushroom polysaccharides was investigated in vitro by exposing them to artificial human gastric juice.ResultsObtained results revealed that fungal polysaccharides stimulate the growth of Lactobacillus strains stronger than commercially available prebiotics like inulin or fructooligosaccharides. Moreover, selected polysaccharides were subjected to artificial human gastric juice and remain undigested in more than 90%.ConclusionObtained results indicate that mushroom polysaccharides are able to pass through the stomach unchanged, reaching the colon and stimulating the growth of beneficial bacteria. Majority of 53 polysaccharide fractions were analysed for the first time in our study. Overall, our findings suggest that polysaccharide fractions from edible mushrooms might be useful in producing functional foods and nutraceuticals.

Streptococcus pneumoniae as an agent of urinary tract infection

Introduction. Streptococcus pneumoniae is a Gram-positive coccus causing mainly otitis media, community-acquired pneumonia, or even an invasive infections as bacteraemia. Generally, it is not accepted as the agent responsible for urinary tract infection (UTI). The case report describes S. pneumoniae isolate from the urine of 63-year-old woman with clinical and bacteriological symptoms of UTI, isolated independently in two bacteriological urine analyses. Results. The urine analyses showed leucocyturia. No other infections or genitourinary disorders were found. The patient was treated with BISEPTOL (trimethoprim/sulfamethoxazole) at a dose of 160/800 mg, twice a day for five days. After the treatment, the urinalysis showed the absence of the microorganisms in bacteriological evaluation. Conclusion. S. pneumoniae is considered to be a rare pathogen of UTI in adults.

New biological activity of the polysaccharide fraction from Cantharellus cibarius and its structural characterization

One of the most commonly consumed mushrooms in Europe is Cantharellus cibarius, also known as chanterelles. Therefore, the investigation of the pro-health properties of crude polysaccharides from this species was performed. The obtained results indicate that the polysaccharide fraction from C. cibarius inhibits the activity of both COX-1 and COX-2. Moreover, the prebiotic potential was revealed in relation to Lactobacillus strains. Crude polysaccharides were found to inhibit the proliferation of colon cancer cells with the simultaneous absence of toxicity towards normal cells. The purification and structural characterization of the examined polysaccharide fraction from C. cibarius indicates that it consists of one monosaccharide in the repeating unit →6)-α-D-Manp-(1→. The presented activities indicate for the first time that this edible mushroom possesses interesting chemopreventive potential, especially against colon cancer.

First report of a Staphylococcus caprae isolated from middle ear fluid of an infant with recurrent acute otitis media

Staphylococcus caprae was originally isolated from goat milk. This uncommon coagulase-negative staphylococcus, usually associated with animals, has only infrequently been detected in human clinical specimens. Its association with acute otitis media has not been demonstrated so far. The study reports the first isolation of S. caprae from the middle ear fluid of a 12-month-old infant with recurrent, bilateral acute otitis media. Biochemical traits and susceptibility pattern of the isolated strain are also presented.

A preliminary report on the susceptibility to aminoglycosides of Escherichia coli isolated from the community-acquired urinary tract infections in adults in south-east Poland

Abstract World-wide, urinary tract infections (UTIs) are an important clinical problem. In such, the most frequently isolated uropathogen is Escherichia coli. In the treatment of uncomplicated UTIs, e.g. cystitis, the widely used antibiotics are nitrofurantoin, trimethoprim/sulfamethoxazole, fosfomycin trometamol or ciprofloxacin, while the treatment of pyelonephritis requires the usage of antibiotics with a broader spectrum of activity, such as cephalosporins of the 3rd and 4th generation, aminoglycosides or even carbapenems. The aim of this study was to assess the susceptibility to aminoglycosides (such as amikacin, gentamicin, netilmicin and tobramycin) of E. coli isolated from UTIs in adult community patients living in Lubelszczyzna. We found that all of the 86 strains of E. coli encountered were susceptible to amikacin. Moreover, the prevalence of susceptibility to tobramycin, gentamicin or netilmicin among the tested strains was found to be 89,5%, 90,7% or 94,2%, respectively. The data obtained in the present study shows the high susceptibility to aminoglycosides of E. coli isolated from the community-acquired UTIS in adults. These data, together with that derived from current literature, indicate that aminoglycosides, when employed in combination therapy with other antibiotics, may still be very useful group of antibacterial agents in the treatment of UTI’s in Poland.