Susceptibility Of Gram-positive Cocci Research Articles

Bacterial Aetiology and Susceptibility of Pathogens Associated with Acne Vulgaris

Introduction: Acne vulgaris is a pilosebaceous disorder among youth during puberty and also in young adults. Hormonal imbalance, bacterial activity and inflammation can cause acne formation. Due to some anti-inflammatory effects and temporary self treatment of acne using some antibiotics, there is overuse/ improper use of antimicrobial agents which leads to resistance in bacterial strains. Aim: To provide an overview of bacteria that may cause acne and determine their susceptibility to antibiotics and reduce the overuse of antibiotics which leads to antibiotic resistance. Materials and Methods: This was a cross-sectional study done on samples from from 100 patients with chief complaints of acne, attending Dermatology Department at Konaseema Institute of Medical Sciences and Research Foundation (KIMS RF). This study was done between November 2019 to February 2021. Acne pustules were cultured on all the basic media like blood agar and Mac Conkey agar, under aerobic and anaerobic conditions. Bacterial identification was performed by gram staining and relevant biochemical tests. Antibiotic susceptibility was done based on the Clinical and Laboratory Standards Institute (CLSI) 2019. Data was calculated and analysed statistically by Statistical Package for Social Science (SPSS) version 21.0. Results: Total 100 participants were taken for the study. Females (63%) were more commonly affected as compared to males (37%) and the most commonly affected age group was teenage i.e., 10 to 20 years in both male and females. Among 100 subjects, 77 cases showed bacterial growth by aerobic and anaerobic culture and 23 cases showed negative for bacterial culture. All isolates were susceptible to rifampin (100%) (p<0.001). Propionibacterium acnes (P. acnes) was susceptible to doxycycline (88.8%) and minocycline (88.8%), while 22.3% was resistant to erythromycin, clindamycin, and tetracycline while 33.3% showed resistance to ofloxacin. Gram positive cocci like Staphylococcus epidermidis (S.epidermidis) was susceptible to the antibiotic minocycline and rifampin (100%); but resistant to quinolines like ofloxacin (52.5%) macrolides like erythromycin (62.5%), clindamycin (47.5%) and tetracycline (17.5%). The susceptibility of gram positive cocci like S. epidermidis to doxycycline was (87.5%), which was lower than that of P. acnes (88.8%). Staphylococcus aureus (S. aureus) was found to be sensitive to minocycline (90.9%), doxycycline (72.7%), clindamycin (63.6%), and tetracycline (63.6%); but it was resistant to macrolide like erythromycin (45.5%) and quinolines like ofloxacin (36.5%). Conclusion: This study suggested that bacterial culture and antibiotic sensitivity can be better suggested if the culture and sensitivity is available so that, sensitivity and resistant pattern is known. The use of clindamycin and macrolide (erythromycin) needs to be reduced as most gram positive cocci like S. epidermidis were resistant to both.

Tepecik Eğitim ve Araştırma Hastanesinde Klinik Örneklerden İzole Edilen Gram Pozitif Kokların Kinopristin/Dalfopristin Duyarlılığının İncelenmesi ve Diğer Antibiyotiklerle Karşılaştırılması

Amaç: Son yıllarda, çoklu ilaca dirençli Gram-pozitif kokların oluşturduğu enfeksiyonların sıklığı artmıştır. Bu mikroorganizmaların neden olduğu enfeksiyonların tedavisinde sorunlarla karşılaşılabilmektedir. Türkiye'de kullanıma girmemiş olan kinopristin/dalfopristin, streptogramin grubundan parenteral uygulanabilen ilk antibiyotiktir. Çalışmamızda, klinik örneklerden izole edilen Gram-pozitif kokların kinopristin/dalfopristin duyarlılığının saptanması ve Gram-pozitif koklara etkili diğer antibiyotiklere olan duyarlılık ile karşılaştırılması sonucunda bu antibiyotiğin klinik kullanabilirliğine ışık tutmak amaçlandı. Gereç ve Yöntemler: Haziran 2008-Haziran 2009 arasında klinik örneklerden izole edilen 279 Gram-pozitif kok çalışmaya alındı. Konvansiyonel yöntemler ve otomatize Vitek 2 (Biomerieux, Fransa) sistemi ile idantifikasyon yapıldı. Antibiyotik duyarlılıkları Kirby-Bauer disk difüzyon yöntemiyle incelendi. Stafilokok türlerinde metisilin direnci sefoksitin diski kullanılarak Clinical and Laboratory Standards Institute (CLSI) kriterlerine göre belirlendi. Penisilin, vankomisin, teikoplanin linezolit ve kinopristin/dalfopristine dirençli kökenlerin, minimal inhibitör konsantrasyonları (MİK) E-testi (AB, Biodisk, Solna, İsveç) yöntemiyle incelendi. Bulgular: Çalışmaya alınan Gram-pozitif koklar arasında koagülaz negatif stafilokok (KNS) (103), Staphylococcus aureus (94), enterokok türleri (50), Streptococcus pneumoniae (21) ve diğer streptokok türleri (11) bulunmaktadır. Kinopristin/dalfopristin duyarlılılığı, metisiline duyarlı stafilokok kökenlerinde %100, metisiline dirençli S. aureus kökenlerinde %93, metisiline dirençli koagülaz negatif stafilokok kökenlerinde %98,1, Enterococcus faecalis kökenlerinde %17,1, Enterococcus faecium kökenlerinde %80, S. pneumoniae kökenlerinde %85,7 ve diğer streptokok kökenlerinde %100 oranında saptanmıştır. Gram-pozitif bakteriler, iki E. faecium izolatı hariç glikopeptit antibiyotiklere duyarlı bulunmuştur. Sonuç: Çalışmaya alınan Gram-pozitif kokların kinopristin/dalfopristin ve diğer antibiyotiklere duyarlılıkları eş zamanlı saptanmıştır. Kinopristin/dalfopristinin Gram-pozitif koklara in vitro duyarlılığının yüksek olması nedeniyle, bu antibiyotiklerin, özellikle çoklu ilaç direnci gösteren ciddi enfeksiyonların tedavisinde diğer ilaçlara alternatif olabileceği, ancak bunun için klinik etkinliği değerlendiren çalışmalara gereksinim olduğu düşünülmüştür.

Susceptibility of gram-positive cocci from 25 UK hospitals to antimicrobial agents including linezolid. The Linezolid Study Group.

The prevalence of antibiotic resistance amongst Gram-positive cocci from 25 UK hospitals was studied over an 8 month period in 1999. A total of 3770 isolates were tested by the sentinel laboratories using the Etest; these bacteria comprised 1000 pneumococci, 1005 Staphylococcus aureus, 769 coagulase-negative staphylococci (CNS) and 996 enterococci. To ensure quality, 10% of the isolates were retested centrally, as were any found to express unusual resistance patterns. The prevalence of penicillin-resistant Streptococcus pneumoniae, vancomycin-resistant enterococci and methicillin-resistant S. aureus (MRSA) varied widely amongst the sentinel laboratories. The resistance rates to methicillin among S. aureus and CNS were 19.2 and 38.9%, respectively, with MRSA rates in individual sentinel sites ranging from 0 to 43%. No glycopeptide resistance was seen in S. aureus, but 6.5% of CNS isolates were teicoplanin resistant and 0.5% were vancomycin resistant. Vancomycin resistance was much more frequent among Enterococcus faecium (24.1%) than E. faecalis (0.5%) (P<0.05), with most resistant isolates carrying vanA. The rate of penicillin resistance in pneumococci was 8.9%, and this resistance was predominantly intermediate (7.9%), with only six hospitals reporting isolates with high level resistance. The prevalence of erythromycin resistance among pneumococci was 12.3%, with the majority of resistant isolates having the macrolide efflux mechanism mediated by mefE. All the organisms tested were susceptible to linezolid with MICs in the range 0.12-4 mg/L. The modal MICs of linezolid were 1 mg/L for CNS and pneumococci, and 2 mg/L for S. aureus and enterococci. Linezolid was the most potent agent tested against Gram-positive cocci, including multiresistant strains, and as such may prove a valuable therapeutic option for the management of Gram-positive infections in hospitals.

A multicentre study: Staphylococcus and Enterococcus susceptibility to antibiotics.

A multicentre study to evaluate the susceptibility of Gram-positive cocci isolated from clinical samples, was performed by six centres working in different areas of Italy. We examined 4,544 strains of Staphylococcus aureus, 4,381 strains of coagulase-negative staphylococci and 2,478 strains of enterococci. The following antibiotics were tested: penicillin G, ampicillin, amoxicillin, piperacillin, imipenem, oxacillin, ofloxacin, pefloxacin, ciprofloxacin, gentamicin, tobramycin, amikacin, netilmicin, rifampicin, clindamycin, tetracycline, cotrimoxazole, erythromycin, chloramphenicol, vancomycin and teicoplanin. Oxacillin-susceptible staphylococci confirmed their susceptibility to many other antimicrobial agents while oxacillin-resistant strains confirmed their multiple and frequent resistance to antibiotics. Resistance to oxacillin, cotrimoxazole and chloramphenicol was more frequent in coagulase-negative staphylococci than in Staphylococcus aureus. Aminoglycosides, rifampicin and quinolones were more active against coagulase-negative staphylococci than against Staphylococcus aureus. Enterococci were susceptible to penicillins and imipenem, and moderately susceptible to ciprofloxacin. Susceptibility of 70-79% was observed with high levels of aminoglycosides. Excellent results against staphylococci and enterococci were observed with vancomycin and teicoplanin.