Antibiotic Resistance Trends of Nasal Staphylococcal Isolates from Namibian School Children

Nasal colonization with Staphylococcus strains puts children at risk of developing difficult-to-treat staphylococcal infections. Antibiotic resistance data is limited in Namibia. Our study thus aimed to provide resistance trends for nasal staphylococci isolated from school children in the Mariental District. This is the first report on antibiotic resistance trends of staphylococci from Namibian school children. By Kirby-Bauer disk diffusion assay, 352 Staphylococcus aureus and 81 coagulase-negative staphylococci (CoNS) isolates from Namibian school children aged 6 - 14 years underwent susceptibility testing against seven antibiotics. Ninety-six percent S. aureus and 66.7% CoNS were resistant to ampicillin. Ampicillin resistance was significantly higher in S. aureus than in CoNS (P S. aureus. Ciprofloxacin was also the most effective drug against CoNS. Cefoxitin/methicillin resistance was seen in 14.5% S. aureus isolates and 8.6% of CoNS. Thirty-one antibiotic resistance patterns were observed, most frequently ampicillin (A), ampicillin-erythromycin (AP-E), and ampicillin-tetracycline (AP-T). Altogether 12.5% isolates (50 S. aureus and four CoNS) were multi-drug resistant. From the methicillin-resistant S. aureus (MRSA) isolates, 43.1% were multi-drug resistant. Methicillin-resistant CoNS were not multi-drug resistant, with the most common resistance pattern being ampicillin-rifampicin-cefoxitin (AP-RP-FOX). In conclusion, multi-drug resistance in our study was relatively low. However, some of the MRSA isolates were multi-drug resistant, which is of concern. Learners should be educated on the importance of handwashing and appropriate use of antibiotics to prevent spread of antibiotic-resistant bacteria within the community. Ciprofloxacin and gentamicin may effectively be used to treat staphylococcal infections in this study population.

Trends in Antimicrobial Resistance against Enterobacteriaceae Strains Isolated from Blood： A 10-year Epidemiological Study in China's Mainland （2004-2014）

Background：Antimicrobial resistance is a serious problem that compromises the empirical treatment of infections,resulting in a lack of effective antibiotics and high medical expenses.Here,we aimed to monitor the trends in antimicrobial resistance among Enterobacteriaceae isolated from blood samples in China's Mainland.Methods：A total of 2240 Enterobacteriaceae isolates from blood were collected from hospitalized patients at 19 tertiary hospitals between October 2004 and June 2014.The minimum inhibitory concentrations of all isolates were determined using the agar dilution method according to the Clinical and Laboratory Standards Institute 2016 guidelines.Results：The most commonly isolated bacteria were Escherichia coli,compromising 47.0% （1053/2240） of the total isolates,followed byKlebsiella spp.（26.3%）,Sahnonella spp.（10.4%）,and Enterobacter spp.（9.2%）.The detection rates of extended-spectrum β-lactamases （ESBLs） among E.coli were 68.9% （2004-2005）,73.2% （2007-2008）,67.9% （2009-2010）,72.6% （2011-2012）,and 58.4% （2013-2014）,whereas those in ESBL-producing Klebsiellapneumoniae were slightly decreased （75.9%,50.0%,41.4%,40.2%,and 43.0%,respectively）.Carbapenems were the most potent agents against the Enterobacteriaceae isolates,followed by moxalactam,tigecycline,and amikacin.However,there was a decrease in the susceptibility rates for carbapenems in all species,particularly K.pneumoniae （decreased by 10.6% for imipenem） and Enterobacter aerogenes （decreased by 2 l.1% for imipenem）.Reviving antibiotics （tigecycline and polymyxins） showed good in vitro activity against Enterobacteriaceae.Conclusions：The activity of antibiotics against Enterobacteriaceae isolated from blood was decreased overall.Large proportions of ESBL-producing isolates were identified among E.coli and Klebsiella spp.Carbapenem-resistant isolates have become a major challenge in the treatment of infections.

Antimicrobial susceptibility of Gram-negative bacteria causing intra-abdominal infections in China： SMART China 2011

Background The Study for Monitoring Antimicrobial Resistance Trends program monitors the activity of antibiotics against aerobic and facultative Gram-negative bacilli （GNBs） from intra-abdominal infections （IAIs） in patients worldwide.Methods In 2011,1 929 aerobic and facultative GNBs from 21 hospitals in 16 cities in China were collected.All isolates were tested using a panel of 12 antimicrobial agents,and susceptibility was determined following the Clinical Laboratory Standards Institute guidelines.Results Among the Gram-negative pathogens causing IAIs,Escherichia coli （47.3％） was the most commonly isolated,followed by Klebsiella pneumoniae （17.2％）,Pseudomonas aeruginosa （10.1％）,and Acinetobacter baumannii （8.3％）.Enterobacteriaceae comprised 78.8％ （1521/1929） of the total isolates.Among the antimicrobial agents tested,ertapenem and imipenem were the most active agents against Enterobacteriaceae,with susceptibility rates of 95.1％ and 94.4％,followed by amikacin （93.9％） and piperacillin/tazobactam （87.7％）.Susceptibility rates of ceftriaxone,cefotaxime,ceftazidime,and cefepime against Enterobacteriaceae were 38.3％,38.3％,61.1％,and 50.8％,respectively.The leastactive agent against Enterobacteriaceae was ampicillin/sulbactam （25.9％）.The extended-spectrum β-lactamase （ESBL） rates among E.coli,K.pneumoniae,Klebsiella oxytoca,and Proteus mirabilis were 68.8％,38.1％,41.2％,and 57.7％,respectively.Conclusions Enterobacteriaceae were the major pathogens causing IAIs,and the most active agents against the study isolates （including those producing ESBLs） were ertapenem,imipenem,and amikacin.Including the carbapenems,most agents exhibited reduced susceptibility against ESBL-positive and multidrug-resistant isolates.