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Objectives: The Dominican Republic lacks reliable information on antimicrobial resistance (AMR), which would allow physicians to prescribe the best treatment for common infectious diseases. This study aimed to define the antimicrobial resistance profiles of the more common pathogens from pediatric services, where data is even more important due to the vulnerability of the population. Methods: We collected data from patients admitted in the pediatric unit of three third level hospitals in the city of Santiago de los Caballeros, Dominican Republic, showing positive bacterial cultures, during a period of two years. Results: Half of the Gram negative pathogens exhibited third generation cephalosporins (3GC) resistance, 17% were resistant to carbapenems. Serratia marcescens presented an exceptionally high proportion of resistance to 3GC (95.9%). Staphylococcus aureus showed elevated resistance to methicillin (58.4%) and even to clindamycin (35.8%). Conclusion: There are elevated levels of antimicrobial resistance among the Enterobacteriaceae family and the Staphylococcus genus isolated from the pediatric population. Necessary measures should be taken to tackle AMR in the country.
Objetivos: La República Dominicana carece de información confiable sobre las resistencias antimicrobianas en el país, lo que permitiría al personal médico prescribir los mejores tratamientos para infecciones comunes. El objetivo de este estudio es definir los perfiles de resistencia antimicrobiana de los patógenos más comunes en servicios pediátricos, donde esta información es esencial, debido a la vulnerabilidad de la población. Métodos: Se tomaron los datos de reportes microbiológicos con cultivo bacteriano positivo procedentes de pacientes admitidos en la unidad pediátrica de tres hospitales de tercer nivel en la ciudad de Santiago de los Caballeros, República Dominicana, durante un periodo de dos años. Resultados: La mitad de los patógenos Gram negativos mostraron resistencia a cefalosporinas de tercera generación (3GC), 17% eran resistentes a carbapenémicos. Serratia marcescens presentó una resistencia excepcionalmente elevada a 3GC (95.9%). Staphylococcus aureus mostró alta resistencia a meticilina (58.4%) e incluso a clindamicina (35.8%). Conclusión: Existen elevados niveles de resistencia antimicrobiana entre las enterobacterias y los estafilococos en la población pediátrica dominicana. Es necesario tomar medidas para abordar este problema en el país.
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Humans , Male , Female , Child , Drug Resistance, Bacterial , Pediatrics , Tertiary Healthcare , Clindamycin , Carbapenems , Dominican Republic , MethicillinABSTRACT
Background: The increasing frequency of MRSA infections and rapidly changing patterns in antimicrobial resistance, led to renewed interest in the usage of Macrolides-Lincosamide-Streptogramin B (MLSB) antibiotics to treat Staphylococcus aureus infection. Clindamycin is an important drug used in the treatment of MRSA and MSSA infection. The aim of this study was to determine inducible and constitutive clindamycin resistance among clinical isolates of Staphylococcus aureus by D-test.Methods: During a period of 6 months from July 2018 to December 2018, a total of 100 Staphylococcus aureus isolated from different clinical samples were subjected to routine antibiotic sensitivity testing by Kirby Bauer’s disc diffusion method. Methicillin-resistance was determined by using the cefoxitin (30 µg) disc. Incidence of MLSBc and MLSBi in Staphylococcus aureus isolates by D-test as per CLSI guidelines.Results: Out of 100 isolates of Staphylococcus aureus obtained from 350 clinical samples, 70(70%) were found to be MRSA and 30(30%) were MSSA. Among 100 Staphylococcus aureus isolates, 40% isolates showed MLSBi resistance, 28% isolates showed MLSBc resistance, 6% isolates showed MS phenotype and 26% isolates showed Sensitive phenotype. MLSBc and MLSBi were found to be higher in MRSA as compared to MSSA (21%, 27% and 7%, 10% respectively). All clinical isolates showed 100% sensitivity to Vancomycin and Linezolid in routine antibiotic susceptibility testing.Conclusions: Continuous surveillance of the MLSB resistance is important and required before the prescription of clindamycin to treat MRSA infections.
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Introduction: Clindamycin has been used to treat pneumoniaand soft tissue and musculoskeletal infections due to MRSA.One important problem in Clindamycin treatment is the riskof clinical failure during therapy caused by MLSB inducibleresistance. The Clinical and Laboratory Standards Institute(CLSI) suggest D-test, which is a phenotypic showingtechnique for inducible Clindamycin resistance.Material and Methods: We analyzed antimicrobialsusceptibility testing by Kirby Bauer disk diffusion method.Methicillin resistance was detected with cefoxitin (30 µg) diskand inducible clindamycin resistance was unwavering in allerythromycin resistant isolate by using D-zone test.Results: 100 S. aureus isolate 37 (36.6%) were methicillinresistant (MRSA) and 63 (63.4%) were methicillin-sensitiveS. aureus (MSSA). Although, mainstream of the MRSAisolates were imitative from pus samples 15, however, the S.aureus isolates imitative from post-operative wound infectionwere mainly MRSA 7. A total of 21 S. aureus isolates withiMLSB phenotype shown that they were 100% susceptible tovancomycin and linezolid, with modest sensitivity (71.14%) togentamicin, cefuroxime and slightest sensitivity to (23.81%)doxycycline, (20.95%) ciprofloxacin.Conclusion: Outstanding to high happening of erythromycinresistance amongst S. aureus isolates, we recommend thatD-zone test have to be regularly done in all laboratories forsuitable recommendation of clindamycin and thus preventingappearance of inducible resistant strains and managementfailure.
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Background: Infections by Gram positive isolates are increasing due to which their antibiotic sensitivity pattern is changing. This has revived interest in Macrolide-Lincosamide Streptogramin Group B (MLSB) antibiotics. Misuse of MLSB antibiotics hasincreased resistance in Gram-positive organisms especially Staphylococcus species to these drugs. Clindamycin is an important drug for treatment of Gram-positive isolates. Hence detection of inducible clindamycin resistance in these clinical isolates is required to prevent therapeutic failure and avoid inadvertent use of this drug. Aim and Objectives: To detect inducible clindamycin resistance among Gram positive isolates obtained from clinical samples. Material and Methods: The study was carried out over a period of one year (Jan-Dec 2018). A total of 461 Gram positive isolates of Staphylococcus species, Streptococcus pneumoniae and Beta-haemolytic Streptococcus were identified from various clinical samples and antibiotic susceptibility done on Vitek2 Compact usi g GP ID, and 628 and ST01 cards respectively. According to CLSI 2017, D-zone test was performed for detection of inducible clindamycin resistance for strains resistant to erythromycin. Results: Staphylococcus aureus (SA) isolates were 59%, Staphylococcus epidermidis (SE) 21%, other Coagulase Negative Staphylococcus (CONS) 16%, Streptococcus pyogenes (Group A-beta haemolytic) 2%, Streptococcus agalactiae (Group B betahaemolytic) 1% and Streptococcus pneumoniae (alpha haemolytic) 1%. Isolates of Methicillin Sensitive Staphylococcus aureus (MSSA) were 58% and Methicillin Resistant Staphylococcus aureus (MRSA) were 42%. Frequencies of MS (clindamycin sensitive) phenotypes, inducible clindamycin resistance (MLSBi) phenotypes and phenotypes showing constitutive resistance (MLSBc) were 44%, 12% and 3% respectively among MSSA and 34%, 39% and 8% respectively among MRSA. Among SE, MS, MLSBc and MLSBi phenotypes were 39%, 24% and 12% respectively and 8%, 44% and 30% respectively among other CONS. One isolate of S. pyogenes was of MLSBi phenotype and none among S. agalactiae and S. pneumoniae. Conclusion: The study emphasizes the significance of conducting D-zone test along with routine antimicrobial susceptibility testing to guide in therapy and avoid treatment failures.
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One of the important factors contributing to emergence of resistant strains in diabetic foot ulcers (DFUs) is inappropriate and widespread use of antimicrobials, either by patients themselves or primary care providers. So routine testing of antibiotic sensitivity plays a crucial role. Also routine test fails to detect Methicillin resistance (MR) which is mediated by mecA, encoding the PBP 2a and inducible Clindamycin resistance (ICR) due to erm genes. Hence, it is advisable to perform MR testing and D test for detection of inducible Clindamycin resistance routinely during the primary antibiotic testing for the knowledge of their prevalence and measures to be taken to control their spread. The present study included 212 diabetic foot ulcer patients, from which 94 (31.33%) gram positive isolates were obtained, of which 75 (25.0%) were Staphylococcus aureus, 9 (3.0%) were Coagulase negative Staphylococci (CoNS) and 10 (3.33%) were Enteroccocus species. Among the Staphylococcal isolates, Methicillin resistance was seen in 25.33% S. aureus and 33.33% CoNS species. Inducible Clindamycin resistance was seen in 20.0% S. aureus and 33.33% CoNS isolates
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OBJECTIVES: Genetic determinants conferring resistance to macrolide, lincosamide, and streptogramin B (MLSB) via ribosomal modification such as, erm, msrA/B and ereA/B genes are distributed in bacteria. The main goals of this work were to evaluate the dissemination of MLSB resistance phenotypes and genotypes in methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from clinical samples. METHODS: A total of 106 MRSA isolates were studied. Isolates were recovered from 3 hospitals in Tehran between May 2016 to July 2017. The prevalence of MLSB-resistant strains were determined by D-test, and then M-PCR was performed to identify genes encoding resistance to macrolides, lincosamides, and streptogramins in the tested isolates. RESULTS: The frequency of constitutive resistance MLSB, inducible resistance MLSB and MSB resistance were 56.2%, 22.9%, and 16.6%, respectively. Of 11 isolates with the inducible resistance MLSB phenotype, ermC, ermB, ermA and ereA were positive in 81.8%, 63.6%, 54.5% and 18.2% of these isolates, respectively. In isolates with the constitutive resistance MLSB phenotype, the prevalence of ermA, ermB, ermC, msrA, msrB, ereA and ereB were 25.9%, 18.5%, 44.4%, 0.0%, 0.0%, 11.1% and 0.0%, respectively. CONCLUSION: Clindamycin is commonly administered in severe MRSA infections depending upon the antimicrobial susceptibility findings. This study showed that the D-test should be used as an obligatory method in routine disk diffusion assay to detect inducible clindamycin resistance in MRSA so that effective antibiotic treatment can be provided.
Subject(s)
Bacteria , Clindamycin , Diffusion , Drug Resistance , Genotype , Lincosamides , Macrolides , Methicillin-Resistant Staphylococcus aureus , Methods , Phenotype , Prevalence , Staphylococcus aureus , Staphylococcus , Streptogramin B , StreptograminsABSTRACT
Background & objectives: Methicillin resistant Staphylococcus aureus (MRSA) isolates with inducible clindamycin resistance (iCR) are resistant to erythromycin and sensitive to clindamycin on routine testing and inducible clindamycin resistance can only be identified by D-test. This study was aimed to detect methicillin resistance and iCR among S. aureus isolates, effectiveness of some commonly used antibiotics and correlation between methicillin resistance and iCR. Methods: The present cross-sectional study included 46 S. aureus isolates subjected to Kirby-Bauer’s disk diffusion method for antibiotic susceptibility testing (AST) to estimate MRSA and resistance to some commonly used antibiotics. D-test was employed to detect iCR. Results: Eleven of the 46 (23.9%) isolates tested were MRSA. Overall, 19 (41.3%) isolates showed of iCR. Vancomycin and linezolid were found to be 100 per cent effective. A positive Karl-Pearson’s coefficient of correlation (0.89) between methicillin resistance and iCR was obtained. Interpretation & conclusions: Detection of iCR is important for the use of clindamycin in MRSA infections. Methicillin resistance and iCR appear to be clinically unrelated.
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Background: The resistance to antimicrobial agents among staphylococci is an increasing problem. Clindamycin is commonly used for the treatment of skin and soft tissue infections produced by Staphylococcus aureus and its widespread use has led to its resistance by different mechanisms & hence it is important to detect this. In vitro, routine tests may fail to detect inducible clindamycin resistance due to erm genes resulting in treatment failure, thus necessitating the need to detect such resistance by a simple D-test on a routine basis. Objective: To find out the percentage of inducible clindamycin resistance in our hospital using D-test and their susceptibilities to other antimicrobial agents to guide therapy. Methods: One hundred and two S. aureus isolates from various clinical samples were evaluated and methicillin resistance was determined using cefoxitin (30 mcg) disc and inducible resistance to clindamycin was detected by D-test as per CLSI guidelines. Antibiotic susceptibility to other antimicrobial agents was done by Kirby Bauer’s disc diffusion method. Results: Nineteen (18%) isolates showed inducible clindamycin resistance, 12 (11%) showed constitutive resistance and 22 (21%) showed MS phenotype. All the three resistance patterns were higher in Methicillin Resistant Staphylococcus aureus (MRSA) as compared to Methicillin Sensitive Staphylococcus aureus (MSSA). Conclusion: Our study showed, that D-test should be used as a mandatory method in routine disc diffusion testing to detect inducible clindamycin resistance for optimum treatment of patients.
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The emergence of resistance to most antimicrobial agents in staphylococci indicates the need for new effective agents in the treatment of staphylococcal infections. Clindamycin is considered to be one safe, effective and less costly agent. We analysed 482 staphylococcal isolates. Detection of inducible clindamycin resistance was performed by the D-test, while the presence of methylases genes: erm (A), erm (B) and erm (C), as well as, macrolide effl ux gene mef was determined by polymerase chain reaction. Inducible clindamycin resistance phenotype was signifi cantly higher in Staphylococcus aureus (S. aureus) strains then in coagulase-negative staphylococci (CNS). Among analysed S. aureus isolates, the predominance of the erm (C) gene, followed by the erm (A) gene were detected. These results indicate that the D-test should be routinely performed on each staphylococcal isolates.
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<p><b>OBJECTIVE</b>To investigate the infection of hospital- and community-acquired "erythromycin-induced clindamycin resistant" strains or D-test positives of clinical isolates of Staphylococcus aureus (S. aureus) (with and without methicillin resistance) in a hospital.</p><p><b>METHODS</b>Strains of S. aureus isolated from clinical specimens were subjected to D-test and antibiotic profiling.</p><p><b>RESULTS</b>Of the total 278 isolates, 140 (50.35%) were D-test positives and the rest were D-test negatives. Further, of 140 (100%) positives, 87 (62.14%) and 53 (37.85%) strains were from males and females, respectively. Of 140 (100%) positives, 117 (83.57%) were methicillin resistant S. aureus and 23 (16.42%) were methicillin sensitive S. aureus; of 140 strains, 103 (73.57%) strains from persons with and 37 (26.42%) were without related infections; of 140 strains, 91 (65%) and 49 (35%) were from hospital- and community-acquired samples, respectively. In 140 strains, 118 (84.28%) with comorbidities and 22 (15.71%) without comorbidities cases were recorded; similarly, persons with prior antibiotic uses contributed 108 (77.14%) and without 32 (22.85%) positive strains. These binary data of surveillance were analyzed by a univariate analysis. It was evident that the prior antibiotic uses and comorbidities due to other ailments were the determinative factors in D-test positivity, corroborated by low P values, P=0.001 1 and 0.002 4, respectively. All isolates (278) were resistant to 17 antibiotics of nine groups, in varying degrees; the minimum of 28% resistance for vancomycin and the maximum of 97% resistance for gentamicin were recorded. Further, of 278 strains, only 42 (15.1%) strains were resistant constitutively to both antibiotics, erythromycin resistant and clindamycin resistant, while 45 (16.2%) strains were constitutively sensitive to both antibiotics (erythromycin sensitive and clindamycin sensitive). Further, of the rest 191 (68.7%) strains were with erythromycin resistant and clindamycin resistant, of which only 140 (50.35%) strains were D-test positives, while the rest 51 (18.34%) strains were D-test negatives.</p><p><b>CONCLUSIONS</b>In view of high prevalence of D-test positive S. aureus strains, and equally high prevalence of multidrug resistant strains both in community and hospital sectors, undertaking of D-test may be routinely conducted for suppurative infections.</p>
Subject(s)
Female , Humans , Male , Anti-Bacterial Agents , Pharmacology , Clindamycin , Pharmacology , Community-Acquired Infections , Epidemiology , Microbiology , Cross Infection , Epidemiology , Microbiology , Drug Resistance, Bacterial , Erythromycin , Pharmacology , Hospitals, Teaching , India , Epidemiology , Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Epidemiology , Microbiology , Staphylococcus aureusABSTRACT
Purpose: The macrolide lincosamide streptogramin B (MLS B ) family of antibiotics serves as an alternative for the treatment of skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA). However, resistance to clindamycin too has emerged, which is of two types, inducible and constitutive. Therapeutic failure is common with inducible type of clindamycin resistance. This study was done to determine the various clindamycin resistance patterns in MRSA isolates and to compare them with minimal inhibitory concentration (MIC) of clindamycin. Materials and Methods: Fifty MRSA isolates were studied by disc approximation test (D test) to detect inducible iMLS B resistance and MIC by agar dilution technique. Results: Of the 50 isolates, 34 were sensitive to both clindamycin and erythromycin. 16 isolates showed different sensitivity patterns; nine of these were positive for D zone indicating inducible iMLS B resistance, five were positive for constitutive MLS B resistance and two showed possible efflux mechanism for macrolide resistance. Out of the 34 sensitive isolates, 5 showed isolated colonies (subpopulation) inside the clindamycin-sensitive zone. When these sub-populations were tested further, two were constitutive MLS B phenotypes, two were inducible iMLS B and one was HD (hazy D zone), which is D + with growth up to clindamycin disc (which is also considered as constitutive MLS B phenotype). Seven isolates showed an MIC of ≥4 μg/ml to clindamycin in spite of being susceptible to both erythromycin and clindamycin by Kirby Bauer disc diffusion technique. Out of these seven isolates, five were those which grew as subpopulation inside the clindamycin-sensitive zone. Conclusion: Detection of iMLS B resistance among MRSA helps to avoid treatment failure with clindamycin. Studying the subpopulation inside the clindamycin-sensitive zone raises the question of existence of hetero-resistance or some other mechanism, which needs further study.
Subject(s)
Anti-Bacterial Agents/pharmacology , Clindamycin/pharmacology , Drug Resistance, Bacterial , Humans , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Microbial Sensitivity Tests/methods , Staphylococcal Infections/microbiologyABSTRACT
The study was conducted to determine the antibiotic susceptibility profile of community-associated methicillin resistant Staphylococcus aureus (CAMRSA) strains isolated from infections. S. aureus strains were isolated from clinical specimens using the standard procedures. CDC definition was used to classify CAMRSA. Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method. Double disk diffusion method (D-test) was used to detect inducible macrolide, lincosamide and streptogramin B resistance (inducible MLS B resistance ) . A total of 83 CAMRSA were isolated from abscesses and other skin infections in persons without known risk factors for MRSA infection. All CAMRSA were susceptible to vancomycin. Out of 83 CAMRSA, 13 (15.65%) were D-test positive (inducible MLS B positive) and 6 (7.23%) were positive for constitutive MLS B resistance. Eight strains (9.63%) were resistant to tetracycline and 26 (31.32%) strains were resistant to erythromycin. Increased rate of inducible clindamycin resistance among CAMRSA indicates the importance of identification of such strains by D test to avoid treatment failure when clindamycin is used.
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BACKGROUND: The Clinical and Laboratory Standards Institute (CLSI) recommends testing for inducible clindamycin resistance in clindamycin non-resistant and erythromycin resistant (CNR-ER) staphylococci by using a D-zone test. Recently, the VITEK2 system was developed to detect inducible clindamycin resistance in staphylococci. We evaluated the performance of the VITEK2 system by comparing it with a D-zone test. METHODS: In detecting inducible clindamycin resistance, a total of 142 clinical isolates of staphylococci were tested by using the VITEK2 Antimicrobial Susceptibility Test (AST)-P601 card (bioMerieux, Marcy l'Etoile, France) and the D-zone test. Of the 142 isolates of staphylococci tested, 114 were CNR-ER staphylococci [40 coagulase-negative staphylococci (CoNS), 74 Staphylococcus aureus] and 28 were staphylococci, either resistant or susceptible to clindamycin and erythromycin (1 CoNS and 27 S. aureus). RESULTS: Of the 114 CNR-ER staphylococci, 98.6% (73/74) of S. aureus and 32.5% (13/40) of CoNS were inducible clindamycin resistant according to the Dzone test. Overall sensitivity and specificity of the VITEK2 system were 98.8% (85/86) and 98.2% (55/56) respectively, and the agreement between the VITEK2 system and the D-zone test was 98.6% (140/142). CONCLUSION: The VITEK2 system shows high concordance with a D-zone test. The inducible clindamycin resistance in staphylococci can be detected easily and conveniently by the VITEK2 system.
Subject(s)
Clindamycin , Erythromycin , Sensitivity and Specificity , Staphylococcus , Staphylococcus aureusABSTRACT
BACKGROUND: While broth based antimicrobial susceptibility test methods work well for the detection of the majority of antimicrobial resistance mechanisms, antimicrobial resistance mechanism in some microorganisms may not be detected by these methods. The purpose of this study was to compare Vitek II system with a standard method for the ability to detect inducible clindamycin resistance in Staphylococcus aureus. METHODS: Of 200 clinical isolates of S. aureus tested, 183 were methicillin resistant (MRSA) and 17 were methicillin susceptible (MSSA). A disk approximation test (Clinical Laboratory Standards Institute; CLSI, Wayne, PA, USA) was performed as the standard method by placing standard erythromycin and clindamycin disks in adjacent positions. Vitek II ID-GPI (bioMerieux, Durham, NC, USA) was used for identification and Vitek AST-P536 (bioMerieux, Durham, NC, USA) for antimicrobial susceptibility tests. RESULTS: Clindamycin resistance rates of S. aureus tested by disk diffusion and Vitek II system were 89% and 56%, respectively. All but one inducible clindamycin resistant MRSA isolates were susceptible to clindamycin by Vitek II system. Five inducible clindmycin resistant MSSA isolates were all susceptible to clindamycin by Vitek II system. Vitek II system did not detect the inducible clindamycin resistance in S. aureus. CONCLUSIONS: Our results showed that Vitek II system was unacceptable for the detection of inducible clindamycin resistance in S. aureus. We suggests that the disk approximation test should be used to detect the inducible clindamycin resistance in S. aureus.