Antibiotic resistance patterns in Pseudomonas aeruginosa: an 8-year surveillance study in a French hospital

The susceptibility to ticarcillin, piperacillin, ceftazidime, aztreonam, tobramycin, amikacin, ciprofloxacin and fosfomycin of 3876 strains of Pseudomonas aeruginosa isolated during the period 1989-1996 in a French hospital was investigated. The most frequently active agents were amikacin and ceftazidime to which 13.3% and 16.1% of the isolates were resistant. Analysis of beta-lactam susceptibility patterns suggested that cephalosporinase derepression and intrinsic resistance were the predominant underlying mechanisms. There was a trend towards a decline in susceptibility to beta-lactams, aminoglycosides and ciprofloxacin over time. Multiresistance was frequent, mainly in O11 and O12 isolates.     

Antibiotic susceptibility patterns of Pseudomonas aeruginosa at a tertiary care hospital in Gujarat, India

Objectives:

The present study was undertaken to assess the antibiotic susceptibility patterns of Pseudomonas aeruginosa at a tertiary care hospital in Gujarat, India. Due to significant changes in microbial genetic ecology, as a result of indiscriminate use of anti-microbials, the spread of anti-microbial resistance is now a global problem.

Materials and Methods:

Out of 276 culture positive samples, 56 samples of Pseudomonas aeruginosa were examined and 10 different types of specimen were collected. Microbial sensitivity testing was done using disk diffusion test with Pseudomonas species NCTC 10662, as per CLSI guidelines.

Results:

The highest number of Pseudomonas infections was found in urine, followed by pus and sputum. Pseudomonas species demonstrated marked resistance against monotherapy of penicillins, cephalosporins, fluoroquinolones, tetracyclines and macrolides. Only combination drugs like Ticarcillin + Clavulanic acid, Piperacillin + Tazobactum, Cefoperazone + Sulbactum, Cefotaxime + Sulbactum, Ceftriaxome + Sulbactum and monotherapy of amikacin showed higher sensitivity to Pseudomonas infections; however, the maximum sensitivity was shown by the Carbapenems.

Conclusion:

From the present study, we conclude that urinary tract infection was the most common hospital acquired infection. Also, co-administration of β -lactamase inhibitors markedly expanded the anti-microbial sensitivity of semi-synthetic penicillins and cephalosporins. The aminoglycoside group of antibiotics - amikacin - demonstrated maximum sensitivity against pseudomonas species. Therefore, use of amikacin should be restricted to severe nosocomial infections, in order to avoid rapid emergence of resistant strains. Periodic susceptibility testing should be carried out over a period of two to three years, to detect the resistance trends. Also, a rational strategy on the limited and prudent use of anti-Pseudomonal agents is urgently required.     

Pseudomonas aeruginosa susceptibility in a university hospital: recognition and treatment

Pseudomonas aeruginosa continues to be a leading cause of nosocomial bacteremia and other serious, often life-threatening infections. The incidence of P. aeruginosa infection appears to be increasing. The resilience of Pseudomonas in the hospital environment, its endogenous virulence factors, and its current level of resistance to antimicrobials make it a formidable pathogen, particularly in a compromised host. Despite the availability of several effective antipseudomonal antibiotics, infections caused by this pathogen are still associated with significant morbidity and mortality. Early recognition and prompt intervention with appropriate antimicrobial agents are vital to successful management. Combination therapy with an aminoglycoside and an extended-spectrum penicillin or cephalosporin is recommended in the initial management of suspected or documented P. aeruginosa infections.     

Characterization of a novel gene related to antibiotic susceptibility in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a human pathogen with increased intrinsic resistance to a large number of antibiotics used in clinical therapy. Therefore, understanding the mechanisms of resistance and developing therapy alternatives for P. aeruginosa are of profound importance. Previous work from our laboratory demonstrated that several mutants have isolated with altered expression of the phzA1B1C1D1E1F1G1 (phzA1) operon in the presence of sub-inhibitory concentrations (SICs) of tetracycline (TET). The present study investigates the roles of the PA0011 gene in mediating phzA1 expression at SIC of TET. The PA0011 gene encodes 2-OH-lauroytransferase by controlling the synthesis of the cell envelope and the outer membrane. We found that the PA0011 mutant strain was susceptible to several different antibiotics and environmental stresses. Complementation in the PA0011 mutant restored these phenotypes to wild-type levels. In addition, expression of the PA0011 gene, as monitored through a luciferase reporter, is increased at SICs of antibiotics. Indeed, the expression of the PA0011 gene increased about threefold in pqsR and pqsH mutants compared with the wild-type PAO1. However, the PA0011 gene negatively regulates the quorum sensing (QS) system. Taken together, these data suggest that PA0011 is involved in susceptibility to antimicrobial agents in P. aeruginosa, and that its susceptibility effect maybe partly dependent on increased QS expression.     

Comparison of antibiotic susceptibility and plasmid content, between biofilm producing and non-producing clinical isolates of Pseudomonas aeruginosa

Bacteria growing as biofilms are less susceptible to antimicrobial agents than free-living cells. Several infectious processes are now recognised to be related to biofilm formation. Pseudomonas aeruginosa is a known biofilm-producing organism and often resistant to several antibiotics. To assess the relationship between biofilm-forming capabilities and antibiotic resistance phenotypes in P. aeruginosa clinical isolates, we evaluated the ability of different phenotypes to form biofilms using 162 clinical isolates of P. aeruginosa. Only 14% of strains produced biofilm after an 8-h incubation and 8% after 24h; the latter group was slightly more multi-resistant, particularly to piperacillin-tazobactam and imipenem. The frequency of 8-h biofilm-formers was higher among isolates resistant to four agents, and that of 24-h biofilm-formers higher among isolates resistant to six antibiotics. Plasmid-content was not related to biofilm formation. In addition to the protection against antibiotics that bacteria gain by growing in a biofilm, clinical isolates forming biofilms seem to accumulate more resistance phenotypes. Bacteria in biofilms may survive antibiotic exposure not only because of the protective effect of biofilm itself, but also because of the increased frequency of resistance traits present.     

Antimicrobial use and Pseudomonas aeruginosa susceptibility profile in a cystic fibrosis centre

The susceptibility patterns of 1315 mucoid and non-mucoid Pseudomonas aeruginosa strains from 224 patients were determined along with antibiotic utilisation in a Cystic Fibrosis Centre from 1993 to 1997. Ceftazidime was the most active agent (86.0% sensitive isolates), followed by piperacillin-tazobactam (81.7%), aztreonam (80.3%), imipenem (80%), piperacillin (76.8%), tobramycin (76.5%), ciprofloxacin (73.7%), ticarcillin (72.4%), ticarcillin-clavulanic acid (70.2%), amikacin (69.5%), netilmicin (56.5%), meropenem (79%) and imipenem (75.5%). The most frequently used compounds were nebulized colistin (mean+/-S.D., 109+/-45 defined daily doses per 1000 patients per day), followed by ciprofloxacin (98+/-8), tobramycin (55+/-9), ceftazidime (31+/-8) and amikacin (55+/-9). The mean antibiotic consumption by our CF patients was 413+/-47 defined daily doses per 1000 patients per day. Trend testing showed a significant decline of susceptibility to aminoglycosides, imipenem and ciprofloxacin, while the susceptibility of P. aeruginosa to piperacillin and ceftazidime was stable.     

某三甲医院铜绿假单胞菌耐药性与抗菌药物使用强度的相关性研究

目的：分析铜绿假单胞菌（PA）耐药率及抗菌药物使用强度（AUD）相关性,结合相关性数据,为抗菌药物的合理使用提供参考依据。方法：调取某院2013年1月至2017年12月住院患者抗菌药物使用情况,并收集同期PA的耐药性数据,利用统计学软件分析其耐药情况与使用强度之间的相关性。结果：PA检出率在这5年内几乎没有波动,较稳定。而多重耐药铜绿假单胞菌（MDR-PA）检出率波动相对频繁,2017年MDR-PA检出率最高,2014年及2015年检出率相对较低;MDR-PA检出率与阿米卡星AUD呈正相关;PA对环丙沙星、阿米卡星耐药率与哌拉西林钠他唑巴坦钠AUD呈正相关;对亚胺培南耐药率与环丙沙星AUD呈正相关。结论：临床在进行抗PA治疗时,应在参照药敏试验结果的基础上,避免长期使用单一品种抗菌药物,及时降阶梯治疗,提高治愈率。     

Increase of imipenem resistance among Pseudomonas aeruginosa isolates from a Polish paediatric hospital (1993-2002)

Analysis of the in vitro activity of imipenem and 13 other antibiotics against 2485 Pseudomonas aeruginosa isolates obtained from clinical specimens from children hospitalized during 1993-2002 was performed. In 2002, the percentage of P. aeruginosa isolates susceptible to all tested antibiotics, with the exception of imipenem, increased or remained on nearly the same level as in 1993. An increase of resistance to imipenem from 4.3% to 18.3% was observed. The MIC(90) value of imipenem increased from 2mg/L to 16 mg/L. Simultaneously, a four-fold increase of the usage of carbapenems imipenem and meropenem in the hospital was noted. In 2000-2001, a high incidence of imipenem-resistant strains was observed. The imipenem-resistant P. aeruginosa strains of serotype O6 from the general surgery ward and serotype O11 from the intensive care unit were shown to be clonally related by the pulsed-field gel electrophoresis method.     

Correlation between the consumption of meropenem or doripenem and meropenem susceptibility of Pseudomonas aeruginosa in a university hospital in Japan

The appropriate use of carbapenems is essential in order to prevent resistance in Pseudomonas aeruginosa. We investigated the correlation between the consumption of meropenem or doripenem and the susceptibility of P. aeruginosa to meropenem in a Japanese university hospital from 2004 to 2009. The susceptibility data of P. aeruginosa and the annual consumption of meropenem or doripenem were analyzed. The consumption of meropenem or doripenem was calculated using the Anatomic Therapeutic Chemical classification and defined daily doses methodology. Meropenem consumption decreased and doripenem consumption increased and throughout the entire investigation period, total consumption of meropenem plus doripenem was stable. Although the annual number of isolated P. aeruginosa has not changed, the annual number of isolated multidrug resistant P. aeruginosa decreased by measures against nosocomial infection. The rate of meropenem resistant P. aeruginosa decreased in a time-dependent manner. Meropenem consumption was positively correlated with the meropenem resistance rate among P. aeruginosa (r = 0.9455, p<0.01). The total consumption of meropenem and doripenem was not correlated with the meropenem resistance rate (r = -0.6601, p>0.1). These results suggested that even if the total consumption of meropenem plus doripenem was not changed, meropenem susceptibility among P. aeruginosa improved by the decrease of meropenem consumption. Although meropenem and doripenem have been suggested to show cross-resistance with each other, the reduction of meropenem consumption might be effective for preventing an increase of meropenem-resistant P. aeruginosa.     

Evaluation of antibiotic use in a hospital with an antibiotic restriction policy

The study was designed to evaluate rational antibiotic use in relation to diagnosis and bacteriological findings. All hospitalized patients who received antibiotics were evaluated by a cross-sectional study. Of the 713 patients hospitalized, 281 (39.4%) patients received 377 antibiotics. Among 30 different antibiotics the most frequently requested were first generation cephalosporins (19.9%), ampicillin-sulbactam (19.1%) and aminoglycosides (11.7%). Antibiotic use was appropriate in 64.2% of antibiotic requests. In analysis of appropriate use, a request after an infectious diseases consultation was a frequent reason (OR=14, P<0.001, CI=0.02-0.24). Antibiotics requested in conjunction with susceptibility results were found to be more appropriate than those ordered empirically (OR=4.5, P=0.017, CI=0.06-0.76). Inappropriate antibiotic use was significantly higher among unrestricted antibiotics than restricted ones (P<0.001). Irrational antibiotic use was high for unrestricted antibiotics. Additional interventions such as postgraduate training programmes and elaboration of local guidelines could be beneficial.     

The effect of an antimicrobial restriction program on Pseudomonas aeruginosa resistance to beta-lactams in a large teaching hospital

STUDY OBJECTIVES: To compare the use of beta-lactams and subsequent Pseudomonas aeruginosa sensitivity patterns before and after implementation of a clinical pharmacist-facilitated antimicrobial restriction program in August 1997. DESIGN: Retrospective consecutive data collection. SETTING: Large university-affiliated medical center. INTERVENTION: The study results are the accumulation of the daily intervention activities of the antimicrobial restriction program. Data on antimicrobial grams purchased/1,000 patient-days and susceptibility patterns were collected and analyzed retrospectively. MEASURES AND MAIN RESULTS: Annual grams of ceftazidime, piperacillin, piperacillin-tazobactam, and other antipseudomonal beta-lactams purchased/1,000 patient-days were compared during the 2 full calendar years before the antimicrobial restriction program (1995-1996) with the 4 full calendar years after the program was implemented (1998-2001). Pseudomonas aeruginosa resistance trends for the antipseudomonal beta-lactams, ciprofloxacin, and tobramycin also were compared for the 2 years before the program (1995-1996) with the last 2 years of the program (2000-2001). A 44% reduction in ceftazidime use was documented; ostensibly, minimal changes occurred in the overall use of piperacillin and piperacillin-tazobactam. During the same time period, ceftazidime resistance fell from 24% to 11.8% (p<0.001), whereas piperacillin resistance fell from 32.5% to 18.5% (p<0.001). Imipenem resistance declined from 20.5% to 12.3% (p<0.001) with an 18% reduction in use. Aztreonam resistance declined from 29.5% to 16.5% (p<0.001) despite a 57% increase in use. No changes in resistance to either ciprofloxacin or tobramycin were found. CONCLUSION: Through an antimicrobial restriction program, a dramatic reduction in ceftazidime use was achieved with judicious use of other antipseudomonal antimicrobials, which resulted in reduced resistance of P aeruginosa to other beta-lactams.     

Serotyping clinical isolates of Pseudomonas aeruginosa in relation to infection site antibiotic susceptibility and beta-lactamase production

The present study investigates the association of O-serotype with isolation site, antibiotic resistance, and beta-lactamase production to determine the profiles of Pseudomonas aeruginosa clinical isolates circulating in a Canadian teaching hospital. The most frequently encountered serotypes of Pseudomonas aeruginosa strains isolated from inpatients at H?tel-Dieu de Montréal hospital during the period 1992-1993 were O1, O3, O5, O6, O10, and O11 (9-13%) isolated from pus, urine, sputa and other sources. Serotype O1 was the most sensitive in contrast to serotype O3 which was resistant to virtually all antibiotics tested except to imipenem and quinolone. Of the strains of Pseudomonas aeruginosa, more than 50% with the most encountered serotype produced a high level of beta-lactamase.     

医院耐碳青霉烯类铜绿假单胞菌的流行及相关因素分析

目的:分析耐碳青霉烯类铜绿假单胞菌(CRPA)发生的流行趋势及相关因素,为CRPA的防治提供临床依据。方法:回顾性分析某院2012年1月-2014年12月946株铜绿假单胞菌对碳青霉烯类的耐药情况,2014年1月-12月281例铜绿假单胞菌阳性患者的临床资料,采用χ²检验、秩和检验、Logistic回归等分析CRPA的发生率及危险因素。结果:CRPA检出率由2012年的41.5%升至2014年的46.9%,与抗菌药物使用强度明显相关(r=0.738,P=0.006)。高龄[相对比值比(OR)=1.028,95%可信区间(95%CI)1.012~1.045,P=0.001]、入住ICU(OR=3.849,95%CI 1.776~8.338,P=0.001)、机械通气(OR=3.313,95% CI 1.504~7.295,P=0.003)和经验性使用广谱抗菌药物(OR=2.352,95%CI 1.136~4.872,P=0.021)是CRPA检出的独立危险因素。在广谱抗菌药物中,使用碳青霉烯类(OR=13.326,95%CI 5.783~30.709,P=0.000)和β-内酰胺酶抑制剂复方制剂(OR=3.273,95%CI 1.403~7.633,P=0.006)与CRPA的检出有关。结论:医院CRPA检出率较高,应加强管理,以减少耐药株的播散和流行。     

我院2007-2011年铜绿假单胞菌分布及耐药性分析

目的:回顾分析我院2007-2011年铜绿假单胞茵(Pseudomonas aeruginosa,PAE)感染分布和耐药性变迁,为临床治疗提供参考.方法:对送检标本进行细菌培养鉴定及药物敏感试验,对病原菌科室分布、标本来源及药敏情况进行分析.结果:5年共分离出1279株PAE,呼吸道标本最多(82.25%),其次为伤口分泌物和尿液.PAE在全院主要科室均有分布,在综合科、ICU、呼吸內科及神经外科分布较多(共59.89%o PAE对氨基糖苷类、喹诺酮类耐药率相对较低,敏感率较高;β-內酰胺类抗生素中,PAE对哌拉西林、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦、头孢吡肟、亚胺培南/西司他丁敏感率均在60%以上,对哌拉西林、亚胺培南/西司他丁耐药率高于另外三种药物;对替卡西林、三代头孢菌素及氨曲南敏感率非常低.结论:近5年来我院PAE耐药严重且有上升趋势.     

2008-2011年我院儿科门诊抗菌药物应用分析

目的评价该院2008--2011年抗菌药物在儿科门诊中的应用情况,为临床合理应用提供参考。方法采用叫顾性办法,对该院2008_2011年儿科门诊中抗菌药物的销售金额、用药频度（DDDs）、限定日费用（DDC）等进行统计、分析。结果该院儿科门诊抗菌药物销售金额占儿科药品总销售金额的30％左右,处方量约占总处方量的20％,4年来比例变化小大,且以口服剂型为主,主要包括青霉素类、头孢菌素类以及大环内酯类抗生索。DDDs排名显示,阿莫西林及阿莫西林／克拉维酸用药频瞍减少,而以头孢克洛为代表的2代头孢以及以头孢地尼为代表的3代头孢的用药频度显著增加。结论该院儿科门诊抗菌药物使用基本合理。     

Isolation-frequency and antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolated in regional core hospitals in the Nagaoka district of Niigata Prefecture (changes for 3 years)

We measured MICs of various antimicrobial agents against Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolated in the Nagaoka district of Niigata Prefecture in 2000 (March-May), 2001 (January-May), and 2002 (March-May). S. pneumoniae: Fifty-six strains were isolated in 2000, 119 strains in 2001, and 88 strains in 2002. In 2000, 2001, and 2002, 24 strains (42.9%), 58 strains (48.7%), and 40 strains (45.5%), respectively, were penicillin-intermediate S. pneumoniae (PISP), and 4 strains (7.1%), 12 strains (10.1%), and 7 strains (8.0%), respectively, were penicillin-resistant S. pneumoniae (PRSP). Carbapenems had the most excellent antimicrobial activity, followed by penicillin G, against penicillin-susceptible S. pneumoniae (PSSP), PISP, and PRSP. H. influenzae: Seventy-six strains were isolated in 2000, 154 strains in 2001, and 91 strains in 2002. In 2000, 2001, and 2002, 6 strains (7.9%), 8 strains (5.2%), and 7 strains (7.7%), respectively, were beta-lactamase-producing ampicillin (ABPC)-resistant strains (MIC > or = 2 micrograms/ml), showing no increase, and 14 strains (18.4%), 70 strains (45.5%), and 31 strains (34.1%), respectively, were beta-lactamase-non-producing ABPC-resistant strains (MIC > or = 2 micrograms/ml), showing a slight increase. Ceftriaxon, meropenem (MEPM), and levofloxacin had excellent antimicrobial activity against these resistant strains. P. aeruginosa: In 2000, 2001, and 2002, 135, 74, and 91 strains, respectively, were isolated, and 14 strains (10.4%), 17 strains (23.0%), and 24 strains (26.4%), respectively, were imipenem-resistant (MIC > or = 16 micrograms/ml), showing a slight increase. MEPM, biapenem, and ciprofloxacin had excellent antimicrobial activity against P. aeruginosa.     

Audit of an antibiotic policy and microbiological investigations for treating bacteraemia in a large teaching hospital

An audit of different approaches to guide empirical therapy in 78 cases of bacteraemia revealed poor utilisation of the antibiotic policy with resulting inadequate (P=0.005) or excessive (P<0.00001) antibiotic treatment and a trend to increased mortality. Eighty-seven percent of blood cultures were positive on Gram-stain within 24 h but streamlined therapy was still judged excessive in 27%. The results show poor utilisation of an up-to-date antibiotic policy but confirm its potential benefits and the ability of traditional culture methods to guide antibiotic therapy in a useful time-scale.     

Staphylococci: frequency of isolation and antibiotic susceptibility patterns in Jimma Hospital, south-west Ethiopia

A total of 493 clinical and environmental specimens were collected from May 1997 to August 1998 from Jimma Hospital wards to determine the frequency of isolation and antimicrobial susceptibility patterns of staphylococci isolates. The specimens were obtained from pus and discharge (32%), blood (22%), urine (18%), nasal swabs (15%), and environmental samples (12%). Of the total 61 S. aureus isolates, 34 (55.7), 15 (24.6%), 8 (13.1%), and 4 (6.6%) were identified from pus and discharge, nasal swabs, blood, and environmental samples, respectively. Coagulase-negative staphylococci (CNS) were also isolated from nasal swabs (48.3%), pus and discharge (29.2%) and environmental samples (13.5%). Multiple antimicrobial resistance was commonly revealed by the S. aureus isolates (84%). Fifty eight (95%), 57 (93%), 43 (72%), and 30 (49%) of the S. aureus isolates were resistant to penicillin, ampicillin, tetracycline, and streptomycin, respectively. Methicillin resistance was also observed in 25 (43%) of the isolates. Similarly, coagulase-negative staphylococci isolates were multi-antimicrobial resistant (96%). The antimicrobial resistance profile of the CNS isolates observed was against penicillin (88%), ampicillin (87%), tetracycline (75%), and chloramphenicol (66%). By contrast, the S. aureus and CNS isolates appeared to be sensitive to gentamicin, kanamycin, and clindamycin. Options available to treat infections caused by multiple resistant staphylococci are limited especially in developing countries. Therefore, the ever growing emergence of antimicrobial resistance requires enhanced surveillance, prudent use of existing antimicrobial drugs, increased emphasis on infection control, and hygienic practices.