Serotypes and resistance to antibiotics of Pseudomonas aeruginosa from wound swabs - Stankovic Nedeljkovic, Natasa S (Vojnosanitetski pregled, 2015)
Abstract Background/Aim. Wound infections caused by Pseudomonas aeruginosa (P.aeruginosa) usually occur after the violation of the skin or mucous membranes integrity. Infections are common in burnes, ulcus cruris or after surgical intervention. The objectives of the examination are analyze the presence of P.aeruginosa in wound swabs, antibiotic susceptibility testing, determination of minimum inhibitory concentrations (MICs) of antibiotics, production of metallo b-lactamase (MBLs), serotyping of isolates and analysis of the resistance of the most common serotypes. Methods. Examination was performed us prospective study in the Microbiological departament ZC’’Aleksinac’’ in Aleksinac since 2012 year. 90 hospital wound swabs and 55 outpatients were cultivated. Wound swabs were taken from patiences, who had a sign of wound infections. Susceptibility testing was performed by disk diffusion method according to CLSI system standards to: meropenem, imipenem, piperacillin-tazobactam, ceftazidime, cefepime, amikacin, gentamicin, netilmicin, ofloxacin, ciprofloxacin and colistin (Himedia). Determination of MICs was performed by the manufacturer’s tape (Liofilchem). MBLs production was determined by disks of imipenem and imipenem with ethylene diamine tetraacetic acid. Polyvalent and monovalent antisera for agglutination (Biorad) were used in the agglutination. Result. P.aeruginosa was isolated from 36.55% wound swabs (36.66% of the nosocomial wounds and 36.36% of outpatients). The most of patiences from whose wounds P.aeruginosa was cultivated had diagnosis ulcus cruris (84%). Analyzed isolates showed the highest degree of sensitivity to colistin (100%), meropenem (93.44%) and imipenem (86.7%), and were the most resistant to cefepime (19.54%). The majority of nosocomial isolates had MICs for piperacillin-tazobactam 12µg/ml (28.57%), and ambulatory 16µg/ml (28.57%). The most common value of MICs for ciprofloxacin for hospital isolates was 0.19µg/ml (31.81%), and outpatient 0.25µg/ml (28.57%). The most common MICs for amikacin of isolates with hospital origin was 6µg/ml (40.9%), and outpatient 4µg/ml (33.33%). Five isolates (9.43%) produced a MBLs (10% of nosocomial isolates and 9.09% of ambulatory). Serotypes P1, P3, P4, P6, P10 and P11 were serologically identified. The most common serotypes were P11 (22.64%), P6 (15.09%) and O1 (11.32%). Conclusion. Analyzed isolates had the highest degree of sensitivity to colistin, meropenem and imipenem, and least to cefepime. Most often serotypes were P11, P6 and P1. Presence of P. aeruginosa in wound cultures and antibiotic resistance in nosocomial isolates compared to outpatient were the similar. This is explained by the specific organisation of the Surgeon’s department, spatially related surgical ward and surgical ambulant, for the same staff and bandaging material sterilizes in one place. Key words: Pseudomonas aeruginosa, wound, resistance, antibiotics, MICs, serotyping Apstrakt Uvod/Cilj. Infekcije rana izazvane Pseudomonas aeruginosa (P.aeruginosa) uglavnom nastaju nakon narušavanja integriteta kože ili sluzokoža. Česte su kod opekotina, ulcus cruris ili nakon hirurških intervencija. Ciljevi ispitivanja su analiza prisustva P.aeruginosa u brisevima rana, ispitivanje osetljivosti na antibiotike, određivanje minimalne inhibitorne koncentracije na antibiotike (MIK), ispitivanje produkcije metalo b-laktamaza (MBL), serotipizacija izolata i analiza rezistencije najčešćih serotipova. Metode. Ispitivanje je sprovedeno kao prospektivna studija u Mikrobiološkoj službi ZC’’Aleksinac’’ u Aleksincu tokom 2012.god. Kultivisana su 90 bolnički i 55 ambulantno uzorkovana brisa rana. Brisevi su uzimani kod bolesnika, koji su imali znake infekcije rana. Ispitivanje osetljivosti na antibiotike je vršeno disk difuzionom metodom po standardima CLSI sistema na: meropenem, imipenem, piperacillin-tazobactam, ceftazidim, cefepim, amikacin, gentamicin, netilmicin, ofloxacin, ciprofloxacin i kolistin (Himedia). Određivanje MIC-a je vršeno po uputstvu proizvođača traka (Liofilchem). Produkcija MBL je određivana diskovima imipenema i imipenema sa etilen diamin tetrasirćetnom kiselinom. U aglutinaciji P.aeruginosa su korišćeni polivalentni i monovalentni serumi za aglutinaciju (Biorad). Rezultat. P.aeruginosa je izolovan iz 36.55% briseva rana (36.66% rana bolničkog porekla i 36.36% ambulantnog). Najveći broj bolesnika kod kojih je kultivisan P.aeruginosa je imalo dijagnozu ulcus cruris (84%). Analizirani izolati pokazali su najveći stepen osetljivosti na kolistin (100%), meropenem (93.44%) i imipenem (86.7%), a najmanji na cefepim (19.54%). Najveći broj izolata bolničkog porekla je imao MIK za piperacilin-tazobaktam 12 µg/ml (28.57%), a ambulantnog 16 µg/ml (28.57%). Najčešća vrednost MIK za ciprofloksacin kod bolničkih izolata je 0.19 µg/ml (31.81%), a ambulantnih 0.25 µg/ml (28.57%). Najčešći MIK za amikacin kod izolata bolničkog porekla je 6 µg/ml (40.9%), a ambulantnog 4 µg/ml (33.33%). Pet izolata (9.43%) je produkovalo MBL (10% izolata bolničkog porekla i 9.09% ambulantnog). Serološki su identifiokvani serotipovi: P1, P3, P4, P6, P10 i P11. Najprisutniji su serotipovi P11 (22.64%), P6 (15.09%) i P1(11.32%). Zaključak. Analizirani izolati su pokazali najveći stepen osetljivosti na kolistin, meropenem i imipenem, a najmanji na cefepim. Najčešće izolovani serotipovi su P11, P1 i P6. Nije uočeno veće prisustvo P.aeruginosa u brisevima rana, niti rezistencija na antibiotike kod izolata bolničkog porekla u odnosu na ambulantne. Ovo se objašnjava specifičnom organizacijom Hirurškog odseka, jer su prostorno povezani Hirurško odeljenje i ambulanta, radi isto osoblje i zavojni materijal se steriliše na jednom mestu. Ključne reči: Pseudomonas aeruginosa, rana, rezistencija, antibiotici, MIK, serotipizacija