Microbiologists fighting superbacteria and antimicrobial resistance

Antimikrobni lijekovi dostupni su za terapijsku uporabu 90-ak godina (računajući od otkrića penicilina 1928. god.), u vremenu tijekom kojeg smo se navikli na činjenicu da se bakterijske infekcije mogu liječiti i izliječiti. Nažalost, bakterije posjeduju savršene mehanizme genske prilagodbe, pa je neminovna posljedica uporabe antibiotika brži ili sporiji razvoj rezistencije. U siječnju 2017. američki Centar za kontrolu i prevenciju bolesti (CDC; engl. Center for Disease Control and Prevention) objavio je da je u Nevadi u Sjedinjenim Američkim Državama umrla žena od infekcije uzrokovane bakterijom otpornom na svaki trenutno dostupan antibiotik1 . Dakle, otpornost na antibiotike ubija. Godišnje najmanje 700 000 ljudi širom svijeta umre od infekcija uzrokovanih rezistentnim bakterijama. Predviđa se da će do 2050. taj broj porasti do 10 milijuna godišnje. Stoga ne čudi što je bakterijska otpornost na antibiotike danas prepoznata kao jedna od najozbiljnijih prijetnji ljudskom zdravlju, koja ne poznaje nacionalne granice

Mobile phones as a potential rezervoar of infection

Cilj: Mikroorganizmi preživljavaju na različitim površinama koje na taj način postaju potencijalni rezervoar infekcije. Cilj ovog istraživanja bio je utvrditi razinu i vrstu mikrobne kontaminacije na mobilnim uređajima studenata Medicinskog fakulteta i laboratorijskih djelatnika u Kliničkom bolničkom centru u Rijeci te utvrditi postoje li razlike s obzirom na spol ispitanika te vrstu tipkovnice mobilnog telefona. Ispitanici i metode: U istraživanju je sudjelovalo ukupno 154 ispitanika, 83 studenata medicine i 71 laboratorijski djelatnik. Uziman je otisak s površine njihovih mobilnih telefona CT3P agarom te se nakon inkubacije od 24 sata na 35±2°C odredio ukupan broj mezofilnih aerobnih bakterija po cm2 (CFU/cm2). Bakterije su identificirane na temelju makroskopskog i mikroskopskog izgleda te odgovarajućih biokemijskih testova. Rezultati: Ukupan broj bakterija, bio je značajno veći u skupini studenata te muških ispitanika. U obje skupine ispitanika na mobilnim uređajima dominiraju Staphylococcus. epidermidis i drugi koagulaza negativni stafilokoki. Međutim, u obje skupine ispitanika utvrđeno je prisustvo Staphylococcus aureus te enterokoka, dok je bakterija iz roda Proteus utvrđena samo u skupini laboratorijskih djelatnika. Nije bilo značajne razlike u mikrobnoj kontaminaciji mobilnih telefona s tipkovnicom u odnosu na one s ekranom osjetljivim na dodir. Zaključak: Razina i vrsta mikrobne kontaminacije na mobilnim uređajima može predstavljati potencijalni izvor infekcije. S obzirom na to da su izolirane bakterije, Staphylococcus aureus, enterokoki te enterobakterije poznati uzročnici bolničkih infekcija, smatramo opravdanim pripremu i uvođenje smjernica za provođenje i kontrolu higijene mobilnih telefona u zdravstvenim ustanovama.Objective: The microorganisms can survive on different surfaces which thus becomes a potential reservoir of infection. The aim of this study was to determine the level and type of microbial contamination on mobile phones from medical students in the Faculty of Medicine and laboratory staff in the Clinical Hospital Centre in Rijeka. Furthermore, the goal was to determine whether there are differences in the microbial contamination of mobile phones between these two groups, the differences based on sex subjects and types of mobile phone keypad. Patients and Methods: The study included a total of 154 participants, 83 medical students and 71 laboratory worker. Surface sapling of their mobile phones was conducted by contact application with CT3P agar and after an incubation of 24 hours at 35 ± 2 ° C the total number of bacteria per cm2 (CFU / cm2) were determined. The bacteria were futher identified based on the macroscopic and microscopic appearance, and various biochemical tests. Results: The total number of bacteria was significantly higher in the group of students and males of both groups. On mobile phones in both groups of participants, Staphylococcus epidermidis and other coagullase negative staphylococci. In addition, the presence of Staphylococcus aureus and pathogens belonging to the genus Enterococcus was found, whil Proteus genotype was found only in a group of laboratory workers. There were no significant differences in microbial contamination of mobile phones with a keyboard than in those with touchscreen. Conclusion: The level and type of microbial contamination on mobile phones can be a potential source of infection. As isolates of bacteria, Staphylococcus aureus, enterococci and enterobacteria are well known cause of hospital infections, further tests within the hospital environment, in order to confirm the validity of the introduction of guidelines for the implementation and control of hygiene of mobile phone in health care facilities are preferred

Global spread of carbapenemase-producing bacteria

Klinički značaj enzima karbapenemaza očituje se u njihovoj sposobnosti hidrolize karbapenema, zbog čega bakterije koje ih proizvode razvijaju otpornost na ovu podskupinu β-laktamskih antibiotika širokog spektra, kao i na većinu ostalih pripadnika iste skupine (penicilini, cefalosporini). Karbapenemaza producirajući sojevi gram-negativnih bakterija od velikog su epidemiološkog značaja, budući da trend širenja ovih β-laktamaza među bolničkim, ali i izvanbolničkim izolatima postaje ozbiljna globalna prijetnja. Često uzrokuju manje ili veće epidemije u zdravstvenim ustanovama. Geni koji kodiraju karbapenemaze obično se prenose na druge bakterije zajedno s genima koji su odgovorni za rezistenciju na ostale skupine antibiotika, kao što su kinoloni i aminoglikozidi. Među najproširenijim karbapenemazama nalaze se metalo-β-laktamaze IMP, VIM i NDM-tipa, a početkom trećeg milenija postali smo svjedoci globalne krize zbog eksplozivnog širenja višestruko otporne Klebsiella pneumoniae koja proizvodi KPC β-laktamazu. Zabrinjava činjenica da pojava i širenje enterobakterija, pseudomonasa i acinetobaktera otpornih na karbapeneme značajno pridonosi povećanom pobolu i smrtnosti pacijenata. Za probir karbapenemaza producirajućih sojeva u mikrobiološkom laboratoriju koriste se klasične fenotipske metode zasnovane na kultivaciji, nakon čega je neophodno potvrditi produkciju enzima primjenom potvrdnih (fenotipskih i/ili molekularnih) metoda. Identifikacija specifičnih gena koji kodiraju enzime temelji se na molekularnim tehnikama. Dijagnostiku i interpretaciju dobivenih laboratorijskih rezultata otežava neprepoznavanje rezistencije nižeg stupnja koja se može javiti u određenom postotku karbapenemaza producirajućih sojeva. Zbog vrlo ograničenog izbora djelotvornih antibiotika vrlo je značajno rano otkrivanje producirajućih sojeva te sprječavanje njihova prijenosa. Pravovremeno otkrivanje inficiranih pacijenata, ali i zdravih kliconoša ključan je korak u prevenciji širenja rezistentnih sojeva bakterija.Carbapenemases are clinically important enzymes because they hydrolyse and inactivate the broad-spectrum β-lactam antibiotics carbapenems. Carbapenemase-producing strains are resistant to carbapenems and to most of the other classes of β-lactams (penicillins, cephalosporins). The growing trend of the carbapenemase-producing strains between inpatient and outpatient isolates of gram-negative bacteria is becoming a global health threat. Infections caused by carbapenemase-producing strains often occur as outbreaks. In addition, carbapenemase- encoding genes are frequently transferred to other bacteria along with the genes responsible for resistance to other classes of antibiotics, such as quinolones and aminoglycosides. The most widespread carbapenemases are metallo-β-lactamase IMP, VIM and NDM-types. At the beginning of the third millennium we witnessed the global spread of KPC-producing, multidrugresistant Klebsiella pneumoniae. The emergence and spread of carbapenem-resistant Enterobacteriaceae, Pseudomonas and Acinetobacter strains leads to an increase in morbidity and mortality rates. Phenotypic methods based on cultivation are used for screening of carbapenemase- producing strains, however, enzyme production must be confirmed by phenotypic or molecular methods. Identification of specific carbapenemase-encoding genes is mainly based on molecular techniques. Low level resistance that can occur in a certain percentage of carbapenemase-producing strains complicates detection and laboratory tests interpretation. Due to the very limited choice of effective antibiotics early detection of carbapenemase-producing strains becomes of paramount importance. Strict infection control measures, including active surveillance for timely detection of colonised patients and prompt isolation of carriers are key steps for preventing the transmission of these bacteria in healthcare settings

The listeriosis triangle: Pathogen, host and the environment

Listeria monocytogenes is a foodborne pathogen well known for its adaptability to diverse environment and host niches and its high fatality rate among infected immunocompromised populations. Infection in the immunocompetent host occurs but risk factors for the disease primarily points to abnormalities in cell-mediated and innate immunity as major predispositions to listeriosis. After ingestion of contaminated food, this pathogen is able to cross the intestinal, blood-brain and placental barrier and leads to gastroenteritis, meningitis and maternofetal infections which may result in abortion and spontaneous stillbirth. Despite the extensive use of this bacterium in the study of cell-mediated immunity and intracellular growth, our understanding of the host, pathogen and environmental factors that impact the pathogenesis of listeriosis is still incomplete. This review will summarize current knowledge, including our own efforts, about pathogen, host and environmental factors that influence, and contribute to the pathogenesis of Listeria monocytogenes infection

MICROBIOLOGY OF RESPIRATORY SAMPLES FROM CHILDREN WITH CYSTIC FIBROSIS

SAŽETAK Analizirani su retrogradno dvogodišnji (2005. – 2006.) rezultati mikrobiološke obrade respiratornih uzoraka dobivenih od bolesnika s cističnom fibrozom, liječenih u Klinici za dječje bolesti KBC-a Rijeka. Od 114 obrađenih kliničkih uzoraka, u 95,6% slučajeva kultura je bila pozitivna, a najčešći izolat bio je Pseudomonas aeruginosa (77,8%). Staphylococcus aureus izoliran u 9,6% uzoraka, dominantan je izolat u mlađe djece. Burkholderia cepacia izolirana je u samo jednome slučaju (0,6%). Dok je među testiranim sojevima vrste Pseudomonas aeruginosa najveći postotak otpornosti uočen prema gentamicinu (49,4%), netilmicinu (47,2%) i ceftazidimu (44,9%), u dvama je izolatima (2,2%) zabilježena otpornost na kolistin.SUMMARY The aim of the study was to analyze the microorganisms cultured from respiratory samples of children with cystic fibrosis treated in the Clinic for children diseases, University Hospital Rijeka, during 2005 – 2006. In 95.6% of 114 clinical samples, microbiological examination yielded positive culture. The most frequently isolated microorganisms was Pseudomonas aeruginosa (77.8%). Staphylococcus aureus was isolated in 9.6% of samples and was dominant in younger CF children. Burkholderia cepacia was isolated just in one case (0.6%). A high resistance to gentamicin (49.4%), netilmicin (47.2%) and ceftazidime (44.9%) was observed in Pseudomonas aeruginosa strains, and two of them were colistin resistant (2.2%)

Systemic and Local CC Chemokines Production in a Murine Model of Listeria monocytogenes Infection

Repeated intragastric inoculation of Listeria monocytogenes into BALB/c mice resulted in prolonged bacteraemia and severe hepatic infection. Bacteria could also be isolated from the brain tissue of all experimental mice. During the inflammatory process, chemokine concentrations typically increased at the local site in comparison to the systemic level. The liver-to-serum ratio was more pronounced in the case of macrophage inflammatory protein 1α (MIP-1α), suggesting its role in the inflammatory response in the liver. The ratio of brain-to-serum concentration of monocyte chemoattractant protein 1 (MCP-1) remained the same as in the control animals, while it was lower in the infected mice, both in the case MIP-1α and in the case of regulated on activation, normal T cell expressed and secreted (RANTES). This is in correlation with slight inflammatory infiltrates found in the brain tissue early in infection

Non-canonical Structures in Promoter Modulate Gene Expression in Escherichia coli

Herein we show how sequences that can form different non-canonical structures affect gene expression levels when inserted in the core of σ70-dependent promoter, between the −35 and −10 elements recognized by RNA polymerase, in E. coli. We note that influence on level of GFP expression varies considerably depending on introduction of non-canonical structural elements in the antisense and sense strands as well as with their propensities to form G-triplex, G-hairpin, hairpin or G-quadruplex structures. Moreover, the extent of repression of expression does not relate to the in vitro thermal stability in a simple manner. Repression is most likely caused by steric interference rather than improper distance between the −35 and −10 elements. Although properties like thermal stability and topology can be somewhat different under in vivo and in vitro conditions, our results suggest that the extent of expression suppression cannot be dependent solely on thermal stabilities of G-rich structures alone. This work is licensed under a Creative Commons Attribution 4.0 International License

Bacteriemia caused by Actinomyces sp. (Microbacterium hydrocarbonoxydans) in a ten-year-old boy with carious dental - a case report

Cilj: Prikaz slučaja bakterijemije, uzrokovane bakterijom Actinomyces sp., kod desetogodišnjeg dječaka s karioznim zubalom. Prikaz bolesnika: Prikazali smo dječaka koji je višekratno hospitaliziran zbog ponavljajućih febriliteta i povišenih upalnih parametara. Tijekom pregleda uočeni su povećani limfni čvorovi smješteni uz stražnji rub sternokleidomastoideusa, palpatorno bezbolni i pomični. Unatrag mjesec dana, višekratno je dobivao peroralne antibiotike radi tonzilofaringitisa praćenog povišenom temperaturom. U uzorcima krvi za hemokulturu porasli su gram pozitivni štapići koji su, Api-Coryne sustavom za identifikaciju, identificirani kao Arcanobacterium haemolyticum. Zbog rijetkosti takvog izolata, soj smo poslali na dodatnu identifikaciju 16S rDNA metodom sekvencioniranja genoma kojom se izolira Actinomyces sp., a Microbacterium hydrocarbonoxydans naknadnom identifikacijom pomoću MALDI-TOF metode. Daljnjom hematološkom obradom pacijenta dokazan je Hodgkinov limfom. Zaključak: Obzirom da API sustavi identifikacije mogu biti nepouzdani, rijetke i neuobičajene izolate kod sistemskih infekcija i(li) bakterijemija potrebno je identificirati pouzdanijim i modernijim sustavima ili molekularnim metodama. Dostupnost molekularnih metoda i masene spektrometrije u rutinskoj laboratorijskoj dijagnostici omogućit će točniju i češću identifikaciju ovakvih izolata. Ako, kod sistemske aktinomikoze i(li) bakterijemije uzrokovane vrstama roda Actinomyces, nema dobrog odgovora na ciljanu terapiju, trebalo bi posumnjati na malignu bolest u pozadini.Objective: To present a case of bacteremia caused by Actinomyces sp. in a ten-year-old boy with carious teeth. Case report: We presented the case of a boy who was hospitalized several times due to recurrent fevers and elevated inflammatory parameters. During the examination, enlarged lymph nodes located along the posterior edge of the sternocleidomastoid, palpably painless and mobile, were observed. Over the past month, he had been receiving oral antibiotics for tonsilopharyngitis accompanied by fever. Gram-positive rods identified by the Api-Coryne identification system as Arcanobacterium haemolyticum were grown in blood samples for blood culture. Due to the rarity of such isolates, the strain was sent for additional identification with 16S rDNA by genome sequencing method to isolate Actinomyces sp., and subsequent identification of Microbacterium hydrocarbonoxydans by applying the MALDI-TOF method. Further haematological treatment of the patient proved Hodgkin\u27s lymphoma. Conclusion: Since API identification systems can be unreliable, rare and uncommon isolates in systemic infections and/or bacteremia should be identified by more reliable and modern systems or molecular methods. The availability of molecular methods and mass spectrometry in routine laboratory diagnostics shall allow more accurate and more frequent identification of such isolates. If there is no good response to targeted therapy in systemic actinomycosis and/or bacteremia caused by species of the Actinomyces genus, underlying malignancy should be suspected

Učestalost onihomikoze na području Zagreba - uloga Sabouraud agara bez cikloheksimida u dijagnostici i terapiji

Mycological analysis is considered the gold standard in the diagnosis of very common fungal diseases of nails. The purpose of the article is to present the prevalence of onychomycosis obtained by using direct microscopic examination (DME) and cultivation on Sabouraud media without cycloheximide. The quantitative retrospective research was conducted on 2706 patients of both sexes (mostly middle-aged to elderly) with various toenail lesions, who had undergone mycological analyses in the Mycological Laboratory of our Department of Dermatovenereology in 2013 and 2014. Analysis of the results obtained revealed that there were 35.4% of positive DME results; of these, there were 39.2% of dermatophytes, 59.1% of yeasts and 1.7% of molds. The percentage of dermatophytes (Trichophyton spp.) was twice as high in men as in women. A considerable percentage (12%) of mixed isolates was also observed. Particularly worrisome was the high percentage (one-third) of suppressed and insufficiently developed dermatophytes (a possible indicator of inappropriate preparation of patients for mycological analysis). Cultivation on culture media without cycloheximide requires frequent inspections because of the fast-growing molds while not allowing sporulation for a great number of dermatophytes. However, it has certain advantages, i.e. it offers an insight into the wide range of the present fungi. As part of the biofilm, they can be potentially pathogenic in dystrophic nails under certain circumstances because, according to our results, the percentage of dermatophytes does not change substantially with aging; however, what does change is the percentage of molds, yeasts and mixed isolates.Mikološka obrada smatra se zlatnim standardom pri dijagnosticiranju vrlo čestih gljivičnih bolesti noktiju i predstavlja temelj za propisivanje antimikotične terapije. Cilj ovoga rada bio je ispitati učestalost onihomikoza na temelju izrade izravnog mikroskopskog preparata i kultivacije uzoraka na Sabouraud podlogama bez cikloheksimida. Provedeno je kvantitativno retrospektivno istraživanje na 2706 ispitanika oba spola kojima je učinjena mikološka obrada zbog različitih vrsta oštećenja noktiju stopala tijekom 2013. i 2014. godine u Mikološkom laboratoriju Klinike za kožne i spolne bolesti Kliničkoga bolničkog centra Sestre milosrdnice u Zagrebu. Analizom dobivenih rezultata utvrđeno je 35,4% pozitivnih izravnih mikroskopskih preparata i izolirano 297 (39,2%) dermatofita, 447 (59,1%) kvasnica i 13 (1,7%) plijesni kao potencijalnih uzročnika onihomikoza. Dermatofiti (Trichophyton spp.) nađeni su u dvostruko većem postotku kod muškog spola. Primijećen je i visok postotak miješanih izolata (12%). Naročito zabrinjava visok postotak suprimiranih (jedna trećina) i nedovoljno razvijenih dermatofita, što se može tumačiti kao pokazatelj nedostatne pripremljenosti bolesnika za mikološku obradu. Iako kultivacija na hranjivim podlogama bez cikloheksimida zahtijeva učestalu inspekciju zbog brzorastućih plijesni, ona ipak nosi određene prednosti. Prvenstveno pruža uvid u širi spektar prisutnih gljiva koje, kao dio biofilma u oštećenim noktima, mogu biti potencijalno patogene u određenim okolnostima. Naime, prema našim rezultatima, sa starenjem populacije ne mijenja se značajno postotak dermatofita, nego se mijenja postotak plijesni, kvasnica i miješanih izolata