The Challenges of Antimicrobial Resistance in Brazil

Transcription

1 ANTIMICROBIAL RESISTANCE George M. Eliopoulos, Section Editor INVITED ARTICLE The Challenges of Antimicrobial Resistance in Brazil Flávia Rossi Pathology Department, DLC_LIM 03, Hospital das Clínicas da Universidade de São Paulo, São Paulo, Brazil Brazil is a country with continental proportions with high geographic and economic diversity. Despite its medical centers of excellence, antimicrobial resistance poses a major therapeutic challenge. Rates of methicillin-resistant Staphylococcus aureus are up to 60% and are related to an endemic Brazilian clone. Local resistance to vancomycin in Enterococci was first related to Enterococcus faecalis, which differs from European and American epidemiology. Also, local Klebsiella pneumoniae and Escherichia coli isolates producing extended-spectrum b-lactamases have a much higher prevalence (40% 50% and 10% 18%, respectively). Carbapenem resistance among the enterobacteriaceae group is becoming a major problem, and K. pneumoniae carbapenemase isolates have been reported in different states. Among nonfermenters, carbapenem resistance is strongly related to SPM-1 (Pseudomonasaeruginosa) and OXA-23 (Acinetobacter baumannii complex) enzymes, and a colistin-only susceptible phenotype has also emerged in these isolates, which is worrisome. Local actions without loosing the global resistance perspective will demand multidisciplinary actions, new policies, and political engagement. Brazil has continental proportions and is the biggest country in Latin America, characterized by many geographic and economic variations, with a population of 192 million inhabitants. São Paulo,inthe southeastern region of the country, is the largest city, with 20 million persons, and has major medical schools. Despite its medical centers of excellence, bacterial resistance in Brazilian hospitals poses a major problem and a treatment challenge [1]. The country does not have a central microbiology reference laboratory, and gathering national data on bacterial resistance is not an easy task because the lack of official publications. Resistance seems to be more relevant in the southern and southeastern states. Recently, local hospitals have had an increasing tendency to consolidate microbiology laboratory services and Received 2 September 2010; accepted 8 November Correspondence: Flávia Rossi, MD, PhD, Rua Eduardo Saigh Filho, 242, São Paulo-SP, Brazil, (frossi@hcnet.usp.br). Clinical Infectious Diseases 2011;52(9): Ó The Author Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please journals.permissions@oup.com /2011/ $37.00 DOI: /cid/cir120 move them off site, leading to a longer turnaround time for culture and antimicrobial susceptibility test results. Even though there are antimicrobial stewardship groups in the majority of the hospitals, delay of microbiology reports may impair specific antibiotic prescriptions, which may, in turn, contribute to a high selective pressure because of large use of broad-spectrum antibiotics [2]. The high consumption of last-resort drugs, such as colistin, is quite frequent in Brazilian intensive care units (ICUs), after many isolates are resistant to almost all currently available drugs [3]. There is evidence that the total consumption of antimicrobials is a critical factor in selecting resistance. Paradoxically, under-use through inadequate dosing, poor adherence, and substandard antimicrobials may play a role as important as over-use in causing resistance. In Brazil, antibiotics still can be bought over-the-counter, leading to self-medication, and this may be a contributing factor for antimicrobial resistance. The increasing prevalence of antimicrobial resistance is a global concern. Brazil and Latin American countries, in general, have higher levels of bacterial resistance among most of its key pathogens, compared with Europe and the United States, particularly among nonfermentative gram-negative bacilli and extended d CID 2011:52 (1 May) d ANTIMICROBIAL RESISTANCE

2 spectrum b-lactamase (ESBL) producing Enterobacteriaceae,but also among some gram-positive organisms (including Staphylococcus aureus) [4, 5]. A brief overview of bacterial resistance of the major pathogens in Brazil will be addressed here. Methicillin-Resistant S. aureus (MRSA) S. aureus is responsible for 20% of nosocomial primary bloodstream infections (BSIs), ranked first among pathogens causing skin and soft-tissue infections, and was the second most frequently isolated pathogen from patients with lower respiratory tract infection in a recent multicenter study [6]. MRSA Brazilian endemic clone (BEC), a hospital-acquired MRSA strain, is 1 of the 5 major global clones, isolates of which are typically resistant to multiple antibiotics. Clindamycin, sulfamethoxazole-trimethoprim, ciprofloxacin, and gentamycin are active against,10% of these MRSA isolates. MRSA-BEC strains also demonstrate reduced phagocytosis and killing by neutrophils and monocytes, compared with susceptible isolates [7]. Data from 2009, proceeding from Hospital das Clínicas of the University of São Paulo, one of the major university hospitals in the country, with 2000 beds, showed that S.aureus BSI was responsible for 15% of the positive blood culture results (counting only 1 isolate per patient); 60% of the cultured organisms were MRSA (author s unpublished data). In general, rates of MRSA infection are even higher in the ICU setting. Rates of MRSA infection from other Brazilian hospitals are 30% 60%. During the past few years, an increasing proportion of MRSA strains causing BSI that are not related to the BEC-MRSA emerged at Hospital das Clínicas of the University of São Paulo. These isolates were susceptible to non b-lactam antimicrobials, were highly susceptible to sulfamethoxazole-trimethoprim, and were designated as non multidrug-resistant and oxacillin-resistant S. aureus. Non multidrug-resistant and oxacillin-resistant S. aureus causing BSI were from hospitalized patients and contained an SCCmec type IV representing another predominant clone; however, these isolates were not of community origin [8] unlike other countries reports. Although MRSA clones bearing a SCCmec type IV have been present in Brazil for a while, the pattern of its dissemination remains to be elucidated [9]. Community-acquired MRSA isolates causing infection are rare, and they are not locally perceived as a prevalent etiological agent [10]. Glycopeptides are still very active against S. aureus despite a few reports of vancomycin-intermediate S. aureus isolates recovered from serious infections. Local microbiology methodology limitations may be masking the detection of hetero vancomycin-intermediate S. aureus and vancomycin MIC (minimum inhibitory concentration) creep. Linezolid appears to retain high activity against monitored gram-positive pathogens at a level of.99.8%. Recently, rare oxazolidinone-nonsusceptible isolates from a large international surveillance study were observed in Brazil, Ireland, Italy, and China. The detected resistance mechanism was a mutation at the G2576 target of ribosomal RNA, and no chloranphenicol forfenicol resitance-mediated (ribosomal methylase) patterns were observed [11]. Vancomycin-Resistant Enterococci (VRE) Previous studies have revealed some differences in the epidemiology of Enterococci in Brazil, the United States, and Europe. Enterococci are prevalent pathogens in the United States, contrasting with Latin America and Brazil, where the bacteria is the eighth or ninth cause of human infection. Resistance to vancomycin in Enterococci in Brazil has been acquired mostly in Enterococcus faecalis contrasting with Enterococcus faecium from United States and Europe. The lack of community reservoirs of VRE in Brazil also contrasts with epidemiological findings from Europe. Avoparcina was not used as a swine growth promoter in Brazil, and this may explain why animal-derived VRE has not spread to humans in the community in our country. Most of the Brazilian ST-17 vancomycin-resistant E. faecium strains do not share a common evolutionary history with isolates from other continents and did not demonstrate an epidemic threat at this time. How the local hospital environment and availability of virulence genes have affected the evolutionary history of ST-17 isolates and the different epidemiological outcome in Brazil remain to be investigate [12]. The first Brazilian VRE strain was isolated only in 1996, sixteen years after the first US report. The VanD-like phenotype of this first E. faecium blood isolate was later classified as VanD4, and multilocus sequence typing (MLST) showed a unique sequence type (ST 281) [12, 13]. There have been several reports of VRE outbreaks in Brazil, including reports of intra-and interhospital spread of strains; however, most of these have had the VanA phenotype and were related to E. faecalis isolates belonging to a major pulsed-field gel electrophoresis (PFGE) pattern [14]. Latin American VRE rates increased from 5.0% in 2003 to 15.5% in 2008, and the most significant increase occurred among isolates from Brazilian centers [6, 15]. Streptococcus pneumoniae In Brazil before 2000, penicillin resistance was lower than that found in other S. pneumoniae isolates from other Latin American countries and was gradually increasing at a lower rate through the years. The National Programme of Invasive S. pneumoniae Surveillance data ( ) analyzed 6470 S. pneumoniae isolates; most of these were from patients,5 years of age who had pneumonia. Serotype 14 was responsible for half of the nonsusceptible isolates in the country and appeared to be associated with the increase of the 7-valent vaccine coverage. A nationwide study of these strains by molecular typing in Brazil identified the emergence and rapid dissemination of 2 international clones, Spain and Tennessee, both expressing the ANTIMICROBIAL RESISTANCE d CID 2011:52 (1 May) d 1139

3 capsule belonging to serotype14. These clones became predominant after 1998, mainly in the southern and southeastern regions, accounting for the highest resistance rates in Brazil. The regional differences are probably related to socioeconomic factors. Penicillin resistance rates increased from 10.2% to 27.9% during that period [16, 17]. Percentages of isolates resistant to sulfamethoxazole-trimethoprim, tetracycline, erythromycin, chloramphenicol, and rifampim were 65%, 15%, 6.2%, 1.3%, and 0.7%, respectively. No levofloxacin resistance was observed. Meningitis isolates showed higher resistance rates to cefotaxime (2.6%), compared with nonmeningitis isolates (0.7%). Brazil isolates had the highest prevalence of sulfamethoxazoletrimethoprim resistance (71.9%) among Latin American countries [17]. Applying current respiratory Clinical Laboratory Standards Institute breakpoints for S. pneumoniae to this data set, the rate of resistance to penicillin is indeed,1%, with virtually no penicillin MICs.4 mg/l. Acinetobacter baumannii Complex (ABC) ABC isolates have emerged as important nosocomial pathogens, causing ventilator-associated pneumonia, bacteriemia, urinary tract infection, and other infections related to major outbreaks in Brazilian ICUs since 1996 [18]. ABC isolates display a prodigious capacity to acquire new determinants of resistance mechanisms, and an increasing recovery of multidrug resistance is becoming a frightening reality in many hospitals worldwide. ABC-carbapenem resistance isolates in Brazil are mostly related to b-lactamase OXA-23, with outbreak reports since 1983 [19, 20]. Recently, a novel carbapenem-hydrolyzing class D b-lactamase (CHDL) OXA-143 was detected among ABC blood isolates in a Brazilian ICU outbreak. This new enzyme showed 63% identity with OXA-23 and is the first member of a novel subgroup of CHDLs for which the prevalence remains to be determined. OXA-143 hydrolyzes penicillin, oxacillin, meropenem, and imipenem but not expanded-spectrum cephalosporins and remained susceptible to ampicillin-sulbactam, colistin, tigecycline, and netilmicin. It may, indeed, be quite prevalent, because resistance to carbapenens in ABC has not always been associated with known carbapenemases, and previously designed primers could not detect this novel gene [21]. The ability to treat serious infections related to ABC isolates is of great concern. The efficacy and safety of ampicillin-sulbactam and polymyxins for treating infection caused by carbapenemresistant ABC was evaluated in two major Brazilian hospitals. Diagnosis of infection was based on Centers for Diseases Control and Prevention criteria and the isolation of ABC from a usually sterile site or a bronchoalveolar lavage fluid specimen. Multiple logistic regression analysis revealed that independent predictors of mortality during treatment were treatment with polymyxins, higher APACHE II score, septic shock, delay in starting appropriate treatment, and renal failure. The most important finding of this study was that ampicillin-sulbactam appeared to be more efficacious than polymyxins [22]. In our institution, ampicillinsulbactam has been restricted for the treatment of ABC infection for.10 years. Brazilian ABC isolates have rates of resistance to carbapenem ranging from 25% to 45%, and as a consequence, polymyxins have been widely used [23]. Because of the lack of new drugs to treat carbapenem-resistant ABC infection, clinicians have considered tigecycline as an option. Currently, there are no Food and Drug Administration breakpoints for this microorganism and/or drug combination, and resistance emergence may occur during treatment. The pharmacological and microbiological profile of tigecycline for each specific patient condition should be carefully assessed, taking into account local ABC susceptibility data to support its use. Tigecycline Evaluation and Surveillance Trial (TEST) data ( ) from Latin America ABC isolates showed a MIC 90,2 mg/l for tigecycline [24]. Pseudomonas aeruginosa Multidrug-resistant P. aeruginosa is a leading cause of nosocomial infections in many Brazilian ICUs, ranking first as a cause of nosocomial pneumonia. High carbapenem resistance rates have been reported among these isolates, resulting from the dissemination of an epidemic clone designated clone SP and also related to the emergence of resistant strains under antimicrobial selective pressure [25]. Efflux systems (mainly MexXY- OprM and MexAB-OprM), porin down-regulation, AmpC overproduction, and b-lactamases including ESBL and Metallo enzymes, particularly SPM-1, interplay a diverse role among Brazilian MDR P. aeruginosa isolates [26]. Carbapenem resistance rates ranged from 40% to 59% in most Brazilian studies, and SPM-1 metallo b-lactamase were detected in almost half of these isolates. IMP and VIM have been eventually detected, but SPM-1 is by far the most prevalent Brazilian metallo b-lactamase [4, 27]. SPM-1 was originally described in São Paulo, and its gene was detected in plasmids and not carried out by integrons, allowing a more effective horizontal dissemination. SPM-1 clonal dissemination is present in distinct Brazilian regions but is still restricted to Brazil [28]. Recently, an SPM-1 isolate in Europe was described, but the patient had previously been in a Brazilian hospital for medical assistance [29]. Fonseca et al applied MLST scheme for determining the epidemiology of colistin-only-sensitive (COS) Brazilian P. aeruginosa clone SP harboring bla SPM-1, and it was demonstrated that this clone had already been circulating outside Brazil before the recent isolate identification in Europe [30]. Isolates presenting the COS phenotype were recovered from different inpatients during from Rio de Janeiro and São Luís, 2 Brazilian cities 3000 km apart. PFGE and MLST analysis showed that the COS P. aeruginosa strains harboring bla SPM-1 clustered together in clone SP and belonged to sequence type (ST) 277, whereas COS SPM-1 negative strains grouped in another clone, and they were 1140 d CID 2011:52 (1 May) d ANTIMICROBIAL RESISTANCE

4 assigned to ST 244. Because the Brazilian clone was previously named clone SP, the same nomenclature was used to define all strains from ST 277. Of interest, according to the P. aeruginosa MLST database, ST 277 had already been assigned to a strain isolated in Austria in 2006, showing the presence of clone SP in Europe before the description by Salabi et al [29]. Moreover, ST 277 was also assigned to isolates from China and Australia, showing its potential to be widespread, its high fitness, and its establishment as an international clone. Nevertheless, there are no data concerning the presence of bla SPM-1 in those isolates from clone SP/ST 277 identified outside Brazil. However, considering that the bla SPM-1 gene is a marker of clone SP in Brazil, it would be of interest to investigate its presence in ST 277 isolates from other countries. ST 244 was assigned to isolates from outbreaks in Poland ( ) and from surveillance studies in China (2006) and the United States ( ), as well as with an environmental isolate from the United Kingdom (1998), showing that this clone is also widespread. The present study associated ST 277 with Brazilian clone SP, which has been revealed as a public health problem, because it presents with a COS resistance profile, beyond its persistence and dissemination in hospitals from a country with continental dimensions, such as Brazil. This study showed that this clone has an epidemic and pandemic potential and that human beings can be vectors promoting its spread [30]. Recently, a bla GES-5 -carrying strain presenting the COS profile in a P. aeruginosa strain emerged in Brazil (Brazilian Amazon), probably as a consequence of point mutation events in the circulating bla GES-1, because the first description of this gene with a truncated attc wasinak. pneumoniae isolate from French Guiana, a country bordering Brazilian Amazon. This isolate imposes an immense limitation on therapy for treating P. aeruginosa infection, increasing the possibility of its persistence and spread in hospital environments. Polymyxin B and colistin have been frequently used in Brazil to treat serious P. aeruginosa infection after many strains demonstrate a COS profile [31]. Enterobacteriaceae Group In Brazilian hospitals, the frequency of ESBL-producing organisms has been higher than in the United States and European hospitals, accounting for 50% from K. pneumoniae isolates recovered from ICU isolates, although molecular characteristics of these ESBL isolates have been poorly described. Locally, ESBL-producing Enterobacteriaceae isolates have emerged in hospital and community settings as an important cause of infections. CTX-M enzymes are the most prevalent among these, with a high diversity of variants common to other Latin American countries (CTX-M2, M8, M9, M14, M15, and M16), and some unique variants, such as CTX-M74 and M75, are suggesting a local evolution [32 34]. According to the 2004 Study for Monitoring Antimicrobial Resistance Trends worldwide results, the ESBL prevalence distribution in the United States, Europe, Latin America, Middle East/Africa, and Asia/Pacific regions among E. coli was 2.8%, 6.4%, 12.0%, 10.0%, and 19.6%; among Klebsiella species was 5.3%, 8.8%, 27.6%, 27.4%, and 22.9%; and among Enterobacter species was 25.3%, 11.8%, 31.1%, 17.8%, and 36.4%. Brazil ESBL isolates from the same study were positive in 10% of E. coli, 17% of Klebsiella species, and 22% of Enterobacter species [35]. TEST results also showed that Latin America had the highest ESBL rates among world regions [5]. Recent surveillance data from 10 Brazilian hospitals (blood isolates only) showed that 54% of K.pneumoniae and 32.4% of E. coli were ESBL positive. Fluoroquinolone resistance was also very high among these isolates (81% and 41%, respectively) (author s unpublished data). The first KPC-producing K. pneumoniae strain was isolated in 2006 in Recife (Northeast of Brazil) and was found to harbor additional enzymes (TEM-1, CTX-M-2, and SHV-11) [36]. One retrospective study showed that KPC-producing K. pneumoniae was present in Brazilian hospitals since at least 2005, but they were not detected at that time [37]. Nowadays the clonal presence of KPC-2 isolates in many Brazilian regions, considering the continental dimensions of this country, is a current threat and highlights current infection control and microbiology laboratory difficulties. These isolates may become a real problem, similar to previous cases of multidrug-resistant organisms, such as SPM-1 producing P. aeruginosa, or epidemic organisms, such as OXA-23 producing A. baumannii [38]. In our institution, KPC first emerged in August 2009, in a urinary tract isolate, and since then, our microbiology laboratory reports at least 1 new case every week posing therapeutic and infection control challenges. Carbapenemase detection by routine clinical laboratories might be difficult when phenotypic standard antimicrobial methods are used [39]. Metallo enzymes in this group were reported in Brazil, but it seems to not be a major problem. New Dehli Metallo is still not present in our country. In summary, Brazil has major challenges to detect and control antimicrobial resistance. Accurate, timely microbiology data and reporting will be critical to the success of our efforts to tackle this problem. Pan-resistant microorganisms combined with the progressive shortage of new compounds are a worrisome situation and deserves local actions without loosing the global view of the problem, because there are no boundaries to this threat. Multidisciplinary action, new polices, and political engagement will be important to minimize the current situation. Acknowledgments Potential conflicts of interest. F.R. has served as a consultant to Astra- Zeneca, Bayer, GSK, MSD, Pfizer, and Sanofi-Aventis at local and international meetings. ANTIMICROBIAL RESISTANCE d CID 2011:52 (1 May) d 1141

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