Methicillin-resistant coagulase-negative staphylococci in healthy dogs

The objective of this study was to evaluate the prevalence of coagulase-negative staphylococci in healthy dogs and to determine whether methicillin-resistant staphylococci expressed the mecA gene. Nasal and rectal swab samples were taken from 50 clinically healthy dogs. The prevalence of coagulase-negative staphylococci was evaluated according to phenotypic properties. The agar diffusion method was applied to evaluate antimicrobial resistance and the prevalence of methicillin resistance was determined using PCR analysing the mecA gene. A total of 59 coagulase-negative staphylococcus strains were isolated from the nostrils and rectums of 37 (74%) clinically healthy dogs. The prevalence of coagulase-negative staphylococci in female dogs was significantly higher compared with male dogs (P < 0.05). The results of antimicrobial susceptibility testing showed that 6.7% of the strains were resistant to oxacillin, 23.7% were resistant to penicillin, 22% to ampicillin and 16.9% to erythromycin. The mecA PCR revealed one oxacillin-sensitive and four oxacillin-resistant coagulase-negative staphylococci strains to be mecA carriers. Staphylococcus sciuri (60%) and Staphylococcus warneri (20%) were the most prevalent species among methicillin-resistant coagulase negative staphylococci. High antimicrobial resistance rates for these bacteria were observed against penicillin (100%), ampicillin (100%), oxacillin (80%), erythromycin (80%) and gentamicin (60%). All strains were susceptible to vancomycin and enrofloxacin. It is assumed that methicillin-resistance genes evolved in coagulase-negative staphylococcus and were then horizontally transferred among staphylococci.

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Determination of the frequency, species distribution and antimicrobial resistance of staphylococci isolated from dogs and their owners in Trinidad

PLoS ONE ◽

10.1371/journal.pone.0254048 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254048

Author(s):

Sharianne Suepaul ◽

Karla Georges ◽

Chandrashekhar Unakal ◽

Filip Boyen ◽

Jamie Sookhoo ◽

...

Keyword(s):

Multidrug Resistance ◽

Antimicrobial Resistance ◽

Species Distribution ◽

Antimicrobial Agents ◽

Methicillin Resistance ◽

Close Contact ◽

Common Species ◽

Diffusion Method ◽

Coagulase Negative Staphylococci ◽

Methicillin Resistant

The close contact between humans and their dogs can lead to the commingling of staphylococci and the exchange of mobile genetic elements encoding antimicrobial resistance. The objectives of this study were to determine the species distribution and antimicrobial resistance patterns of staphylococci colonizing canine pets and their owners in Trinidad. Staphylococci were isolated from canine pets and their owners and identified using MALDI-TOF mass spectrometry. Antimicrobial susceptibilities were determined using the Kirby-Bauer disc diffusion method against seven classes of antimicrobial agents. A total of 440 staphylococci were isolated from 112 canine pets and their owners, 53.4% were from canine pets and 46.6% were from owners. Twenty-four species were detected, of which, most isolates (32.5%) belonged to the Staphylococcus intermedius group (SIG). S. sciuri was the most common species of coagulase-negative staphylococci (CoNS) comprising 22.3% of all isolates. Antimicrobial resistance was highest against commonly used antimicrobials, such as penicillin (51.4%), tetracycline (26.1%) and trimethoprim/sulfamethoxazole (18.6%). These antimicrobials also comprised the most common multidrug resistance (MDR) combination. Overall, 19.1% of isolates displayed multidrug resistance. No methicillin-resistant Staphylococcus aureus (MRSA) isolates were detected. However, methicillin resistance was detected in 13.3% and 15.1% of coagulase-positive staphylococci (CoPS) and the CoNS+CoVS (combined CoNS and coagulase-variable staphylococci) group respectively. The presence of methicillin-resistant staphylococci is worrisome because there is the potential for the transfer of these strains between dogs and humans. These strains may act as a reservoir of resistance genes.

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Coagulase-positive methicillin-resistant Staphylococcus aureus circulating in clinical mastitic goats in Bangladesh

Veterinary World ◽

10.14202/vetworld.2020.1303-1310 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1303-1310

Author(s):

Eaftekhar Ahmed Rana ◽

Tridip Das ◽

Avijit Dutta ◽

Mizanur Rahman ◽

Mohammad Bayazid Bostami ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Meca Gene ◽

Diffusion Method ◽

Coagulase Negative Staphylococcus ◽

Clinical Parameters ◽

Coagulase Negative Staphylococci ◽

Disk Diffusion Method ◽

Methicillin Resistant ◽

Lactating Goats ◽

Staphylococcus Spp

Background and Aim: Staphylococcus aureus is argued as one of the principal organisms responsible for mammary gland infection in lactating goats, causing both clinical and subclinical mastitis. Being highly zoonotic potential, pathogen emergence of methicillin-resistant S. aureus (MRSA) has a significant clinical impact on treatment and management of clinical mastitis. We conducted a cross-sectional study to investigate the prevalence of coagulase-positive S. aureus (CoPS), antimicrobial resistance profile of Staphylococcus spp., prevalence of MRSA, and association between different clinical parameters with CoPS. Materials and Methods: A total of 67 clinical mastitic goats were sampled based on clinical examination and California mastitis test. Standard bacteriological methods were performed to isolate and identify Staphylococcus spp. CoPS were confirmed by nuc gene using polymerase chain reaction (PCR). All staphylococcal isolates were further examined for antimicrobial susceptibility testing by disk diffusion method. MRSA was confirmed based on mecA gene-based PCR. Results: Here, 49 (73.13%; 95% confidence interval [CI], 61.41-82.35) samples were positive for Staphylococcus spp., of which 17 (34.69%; 95% CI, 22.88-48.73) isolates were CoPS and rest of the isolates (32; 65.30%; 95% CI, 51.27-77.12) were identified as coagulase-negative Staphylococcus spp. (coagulase-negative staphylococci [CNS]). Both, CoPS and CNS isolates displayed the highest resistance against tetracycline (76.47% and 75%, respectively) and oxacillin (70.58% and 68.75%, respectively). Notably, all staphylococcal isolates were multidrug-resistant (showed resistance to ≥3 classes of antimicrobials). mecA gene was found in 6 (8.96%; 95% CI, 3.84-18.52) CoPS isolates indicating MRSA strains. Among different clinical parameters, presence of high body temperature (p<0.05), firm udder consistency (p<0.01), bloodstained milk (p<0.00), and pus in milk (p<0.00) were significantly associated with the presence of CoPS in mastitic caprine milk. Conclusion: To the best of our knowledge, this is the first report of MRSA isolated from clinical caprine mastitis cases in Bangladesh. The findings of this study would help in cautious selection as well as administration of antimicrobials for therapeutic management of mastitic goats.

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Occurrence and characteristics of methicillin resistant Staphylococcus aureus and methicillin resistant coagulase-negative staphylococci in raw milk manufacturing

Czech Journal of Food Sciences ◽

10.17221/4443-cjfs ◽

2012 ◽

Vol 29 (Special Issue) ◽

pp. S11-S16 ◽

Cited By ~ 11

Author(s):

M. Vyletělová ◽

H. Vlková ◽

I. Manga

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Methicillin Resistance ◽

Meca Gene ◽

Diffusion Method ◽

Biochemical Tests ◽

Coagulase Negative Staphylococci ◽

Disk Diffusion Method ◽

Methicillin Resistant ◽

Staphylococcal Cassette Chromosome

For monitoring the occurrence of MRSA (methicillin resistant Staphylococcus aureus) and MR-CNS (methicillin resistant coagulase-negative staphylococci), cow’s, goat’s, and sheep’s milks (bulk milks and individual samples) were investigated. Human nasal and throat swabs of the farm staff and nasal swabs of animals were also investigated as well. In total 1729 samples were examined and 634 strains were isolated by means of the cultivation method and used in this study. Generic identification of the staphylococci isolates was done performed by biochemical tests and all S. aureus and CNS isolates were checked by the PCR method for the presence of mecA gene which is responsible for methicillin resistance. The presence of the staphylococcal cassette chromosome mec (SCCmec), Panton-Valentine leukocidin (pvl) and genes encoding toxic shock syndrome toxin (tst) was detected in all strains confirmed as MRSA. The species were also examined for antimicrobial susceptibility by using disk diffusion method with antibiotic disks. S. aureus was the most frequently identified species from the samples tested (n = 557; 32.2%), followed by S. haemolyticus (n = 32; 1.9%), S. chromogenes (n = 24; 1.4%), S. epidermidis (n = 20; 1.2%), and S. caprae (n = 1; 0.16%). Among the resistant staphylococci (n = 49), S. aureus (n = 25; 51%) was found the most frequently, followed by S. epidermidis (n = 17; 34.7%), S. chromogenes (n = 6; 12.2%), and S. haemolyticus (n = 1; 2%). The resistant Staphyloccocus sp. occurred mainly in cow’s milk (MRSA, S. epidermidis, S. chromogenes, S. haemolyticus) and in animal’s swabs (S. epidermidis). One MRSA was also found in goat’s milk and one was isolated from human swab. No resistant strains were found in sheep’s milk. The negative results of the analysed genes presence (pvl, tst) were identical with all MRSA tested. The staphylococcal cassette chromosome mec (SCCmec) was classified as type IV or V.

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Isolation and antimicrobial resistance of coagulase-negative staphylococci recovered from healthy tortoises in Minas Gerais, Brazil

Ciência Rural ◽

10.1590/0103-8478cr20210354 ◽

2022 ◽

Vol 52 (7) ◽

Author(s):

Jordana Almeida Santana ◽

Brendhal Almeida Silva ◽

Nathalia Abreu Borges Trevizani ◽

Angélica Maria Araújo e Souza ◽

Grécia Mikhaela Nunes de Lima ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Antimicrobial Susceptibility ◽

Methicillin Resistance ◽

Meca Gene ◽

Companion Animals ◽

Minas Gerais ◽

Diffusion Method ◽

Coagulase Negative Staphylococci ◽

Mannitol Salt Agar ◽

Antimicrobial Resistance Genes

ABSTRACT: In the last few decades, there has been a global increase in the adoption of reptiles as companion animals, mainly turtles and tortoises. Considering the popularity of reptiles as pets in Brazil, and a notable lack of data about potentially pathogenic staphylococci in these animals, this study isolated and evaluate the antimicrobial susceptibility of staphylococcal species from healthy tortoises (Chelonoidis carbonaria) in Brazil. During a 12-month period (February 2019 to February 2020), cloacal swabs from 66 healthy tortoises were collected at the Wild Animals Screening Center in Belo Horizonte, Minas Gerais, Brazil. The swabs were plated onto mannitol salt agar for staphylococci isolation, and species identification was performed using MALDI-TOF MS. Antimicrobial susceptibility was investigated using the disk diffusion method, and the presence of the mecA gene was investigated by PCR to detect methicillin resistance. Of the tested animals, 72.7% were positive for staphylococcal isolation. All isolates were coagulase-negative staphylococci (CoNS), and Staphylococcus sciuri (81.3%), and S. xylosus (12.5%) were the most frequently isolated species. The majority of the isolates (56%) were resistant to at least one antimicrobial agent. A high frequency of resistance was observed for penicillin (35.5%) and tetracycline (29.1 %). All strains were susceptible to cefoxitin, chloramphenicol, ciprofloxacin, erythromycin, and gentamicin. All isolates were negative for the mecA gene. The present work suggests that healthy tortoises are mainly colonized by CoNS, especially S. sciuri. Half of the isolates were resistant to at least one antimicrobial, raising questions regarding the possible role of these animals as reservoirs of antimicrobial resistance genes.

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Staphylococci among Wild European Rabbits from the Azores: A Potential Zoonotic Issue?

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-423 ◽

2020 ◽

Vol 83 (7) ◽

pp. 1110-1114 ◽

Cited By ~ 1

Author(s):

MARGARIDA SOUSA ◽

VANESSA SILVA ◽

ADRIANA SILVA ◽

NUNO SILVA ◽

JESSICA RIBEIRO ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Resistance Genes ◽

Meca Gene ◽

Diffusion Method ◽

Coagulase Negative Staphylococci ◽

Spa Typing ◽

Disk Diffusion Method ◽

Genetic Lineages ◽

Antimicrobial Resistance Genes ◽

European Rabbits

ABSTRACT The prevalence and diversity of Staphylococcus species from wild European rabbits (Oryctolagus cuniculus) in the Azores were investigated, and the antibiotic resistance phenotype and genotype of the isolates were determined. Nasal samples from 77 wild European rabbits from São Jorge and São Miguel islands in Azores were examined. Antibiotic susceptibility of the isolates was determined using the Kirby-Bauer disk diffusion method, and the presence of antimicrobial resistance genes and virulence factors was determined by PCR. The genetic lineages of S. aureus isolates were characterized by spa typing and multilocus sequence typing. A total of 49 staphylococci were obtained from 35 of the 77 wild rabbits. Both coagulase-positive (8.2%) and coagulase-negative (91.8%) staphylococci were detected: 4 S. aureus, 17 S. fleurettii, 13 S. sciuri, 7 S. xylosus, 4 S. epidermidis, and 1 each of S. simulans, S. saprophyticus, S. succinus, and S. equorum. The four S. aureus isolates showed methicillin susceptibility and were characterized as spa type t272/CC121, Panton-Valentine leukocidin negative, and hlB positive. Most of the coagulase-negative staphylococci showed resistance to fusidic acid and beta-lactams, and multidrug resistance was identified especially among S. epidermidis isolates. The mecA gene was detected in 20 isolates of the species S. fleurettii and S. epidermidis, associated with the blaZ gene in one S. epidermidis isolate. Five antimicrobial resistance genes were detected in one S. epidermidis isolate (mecA,dfrA,dfrG,aac6′-aph2′′, and ant4). Our results highlight that wild rabbits are reservoirs or “temporary hosts” of Staphylococcus species with zoonotic potential, some of them carrying relevant antimicrobial resistances. HIGHLIGHTS

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1219. Increasing Methicillin Resistance of Staphylococcus lugdunensis in a Tertiary Care Community Hospital in Japan

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.1052 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S370-S370

Author(s):

Takahiro Ichikawa ◽

Fumihiro Kodama

Keyword(s):

Community Hospital ◽

Methicillin Resistance ◽

Tertiary Care ◽

Meca Gene ◽

Coagulase Negative Staphylococcus ◽

Staphylococcus Lugdunensis ◽

Methicillin Resistant ◽

Healthcare Facilities ◽

Care Community ◽

Resistant Strains

Abstract Background Staphylococcus lugdunensis, a coagulase-negative staphylococcus, has virulence and pathogenicity similar to that of Staphylococcus aureus. Methicillin resistance and presence of mecA gene are not common in S. lugdunensis in many parts of the world. Recently, higher prevalence of methicillin-resistant S. lugdunensis is reported from Taiwan and Japan. We describe the change in methicillin resistance of S. lugdunensis in a tertiary care community hospital in Sapporo, Japan. Methods We performed a retrospective study of S. lugdunensis, isolated from inpatients and outpatients at our hospital from 2008 to 2017. Rate of methicillin resistance of the first 5 years from 2008 to 2012, and that of the second 5 years from 2013 to 2017 were compared. Risk factors of methicillin resistance were also evaluated. Phenotypic detection of methicillin resistance was identified using broth microdilution by VITEK two system (bioMérieux). Results A total of 369 cases of S. lugdunensis were detected during the study period. Of all cases, 228 (61.8%) were men, and 177 (48.0%) were hospitalized. Twenty-one isolates (5.7%) were positive in blood culture, 216 (58.5%) were positive in cultures of skin and soft tissue. Methicillin-resistant strains were found in 43 (31.6%) of 136 isolates from 2008 to 2012, and in 108 (46.4%) of 233 from 2013 to 2017 (OR 1.87; 95% CI 1.20–2.91; P = 0.006). Of patients with methicillin-resistant S. lugdunensis, 105 cases (69.5%) were hospitalized (P < 0.001). Conclusion In our hospital, methicillin-resistant S. lugdunensis is increasing over the 10 years. Further research is needed to assess trend of methicillin resistance of S. lugdunensis in other healthcare facilities and countries. Disclosures All authors: No reported disclosures.

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Frequency and Characterization of Antimicrobial Resistance and Virulence Genes of Coagulase-Negative Staphylococci from Wild Birds in Spain. Detection of tst-Carrying S. sciuri Isolates

Microorganisms ◽

10.3390/microorganisms8091317 ◽

2020 ◽

Vol 8 (9) ◽

pp. 1317

Author(s):

Laura Ruiz-Ripa ◽

Paula Gómez ◽

Carla Andrea Alonso ◽

María Cruz Camacho ◽

Yolanda Ramiro ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Virulence Genes ◽

Meca Gene ◽

Virulence Gene ◽

Wild Birds ◽

Diffusion Method ◽

Coagulase Negative Staphylococci ◽

Disk Diffusion Method ◽

Resistance Phenotype ◽

Antimicrobial Resistance Genes

The objective of this study was to determine the prevalence and diversity of coagulase-negative staphylococci (CoNS) species from wild birds in Spain, as well as to analyze the antimicrobial resistance phenotype/genotype and the virulence gene content. During 2015–2016, tracheal samples of 242 wild birds were collected in different regions of Spain for staphylococci recovery. The species identification was performed using MALDI-TOF. The antimicrobial resistance phenotype and genotype was investigated by the disk diffusion method and by PCR, respectively. The presence of the virulence genes lukF/S-PV, tst, eta, etb, etd and scn was investigated by PCR. Moreover, CoNS carrying the mecA gene were subjected to SCCmec typing. Of the tested animals, 60% were CoNS-carriers, and 173 CoNS isolates were recovered from the 146 positive animals, which belonged to 11 species, with predominance of S. sciuri (n = 118) and S. lentus (n = 25). A total of 34% of CoNS isolates showed a multidrug resistance phenotype, and 42 mecA-positive methicillin-resistant CoNS (MRCoNS) were detected. The isolates showed resistance to the following antimicrobials (percentage of resistant isolates/antimicrobial resistance genes detected): penicillin (49/ blaZ, mecA), cefoxitin (24/ mecA), erythromycin and/or clindamycin (92/ erm(B), erm(C), erm(43), msr(A), mph(C), lnu(A), lsa(B), vga(A) and sal(A)), gentamicin and/or tobramycin (5/ aac(6′)-Ie-aph(2″)-Ia, ant(4′)-Ia), streptomycin (12/str), tetracycline (17/ tet(K), tet(L), tet(M)), ciprofloxacin (4), chloramphenicol (1/ fexA), fusidic acid (86/ fusB, fusD) and trimethoprim–sulfamethoxazole (1/ dfrK). None of the isolates harbored the lukF/S-PV, eta, etb, etd and scn genes, but two S. sciuri isolates (1%) carried the tst gene. Wild birds are frequently colonized by CoNS species, especially S. sciuri. We identified scavenging on intensively produced livestock and feeding on landfills as risk factors for CoNS carriage. High proportions of MRCoNS and multidrug resistant CoNS were detected, which coupled with the presence of important virulence genes is of concern.

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Virulence gene profile and antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis in Kashmir, India

Journal of Applied and Natural Science ◽

10.31018/jans.v9i2.1294 ◽

2017 ◽

Vol 9 (2) ◽

pp. 893-898 ◽

Cited By ~ 1

Author(s):

Nazima Nazir ◽

Shakil Ahmed Wani ◽

Qazi Nyrah ◽

Shaheen Farooq ◽

Mir Nadeem Hassan ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Meca Gene ◽

Bovine Mastitis ◽

Pcr Amplification ◽

Virulence Gene ◽

Gene Profile ◽

Methicillin Resistant ◽

Pathogenic Factors ◽

Mastitic Milk ◽

Resistance Rates

The Staphylococcus aureusis often responsible for a number of diseases in humans and animals, and it is considered as a main etiological agent of bovine mastitis. The pathogenicity of S. aureus is due to both its ability to resist antibiotics, and the production of toxins. This study investigated virulence genes, prevalence and antibiogram profile of S. aureus isolated from dairy cows suffering from mastitis in the Kashmir. A total of 70 S. aureus isolates were obtained from 250 mastitic milk samples collected from both organized (47/150) and unorganized (23/100) dairy farms. Five pathogenic factors including clfA, hld, seo, lukM, and coa and one resistance gene mecAgene were checked through PCR. Clumping factor gene (clfA) was found in most of the isolates with a percentage of 81.42 % whereas,hld, seo, lukM, and coa were present in 61.2, 54.28, 70, and 71 percent of isolates, respectively. However, amplification of coagene yielded DNA bands of two different sizes. A high percentage of antimicrobial resistance rates were observed, wherein, Ampicillin showed highest resistance with 85.7 %, followed by Kanamycin, Cefotaxime, Sulphadizine and Streptomicin showing 71.42 %, 54.28 %, 51.48 % and 42 %, respectively. A high frequency of Methicillin resistant S. aureus (MRSA 28.57 %) was observed in these isolates and all methicillin resistant isolates were found to be positive for mecA gene via PCR amplification. These results revealed that mastitis-associated S. aureus among bovines of Kashmir is able to accumulate different virulence factors and resistance to antimicrobials, making the treatment of infections difficult.

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Molecular characterization of methicillin-resistant staphylococci among apparently healthy students

Zinc supplementation improves heme biosynthesis in rats exposed to lead ◽

10.18051/univmed.2019.v38.25-32 ◽

2019 ◽

Vol 38 (1) ◽

pp. 25

Author(s):

Helen Oroboghae Ogefere ◽

Lawrence Ayodele Ogunleye

Keyword(s):

16S Rrna ◽

Methicillin Resistance ◽

Transmission Rate ◽

Meca Gene ◽

Performance Standards ◽

Control Measures ◽

Diffusion Method ◽

Methicillin Resistant ◽

Band Size ◽

Apparently Healthy

Background Staphylococcus aureus are widely considered a major factor of nosocomial and community-acquired infections. This work was aimed at determining the prevalence of methicillin-resistant S. aureus (MRSA) among apparently healthy students. Methods A cross-sectional study was conducted involving 400 nasal swab samples randomly collected from students using sterile swab sticks and processed to recover S. aureus using standard microbiological techniques. Conventional methods were used to identify the isolates and antibiotic susceptibility tests were performed using Kirby-Bauer disc diffusion method according to performance standards of Clinical and Laboratory Standard Institute guidelines. Methicillin-resistance was detected phenotypically using cefoxitin 30µg discs. Bacterial deoxyribonucleic acid (DNA) extraction was done on cefoxitin-resistant staphylococci isolates only using ZymoResearch (ZR) fungal/bacterial DNA MiniPrepTM kit. A polymerase chain reaction assay targeting the 16S rRNA, nuc, and mecA genes on 1.0% agarose gel electrophoresis stained with ethidium bromide was used to identify S.aureus and detect methicillin resistance. Results The overall prevalence of MRSA was 5.8% using phenotypic methods. PCR amplification of the 23 phenotypically confirmed MRSA using 16S rRNA and nuc genes identified staphylococci 23/23(100%) and S. aureus 23/23(100%) at band size 886bp and 225bp respectively. However, 16(69.6%) were positive for mecA gene at band size 532bp by PCR method. Poor level of susceptibility was recorded among the MRSA namely to erythromycin (26.6%), cloxacillin (0%), augmentin (0%), cefuroxime (0%), ceftriaxone (0%) and ceftazidime (0%). Ofloxacin was the most effective antibiotic (60.9%). Conclusion Active antimicrobial surveillance of pathogenic staphylococci is important to analyze the infections and transmission rate for possible control measures.

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A study of inducible clindamycin resistance in erythromycin resistant clinical isolates of Staphylococcus species

Asian Journal of Medical Sciences ◽

10.3126/ajms.v6i6.11811 ◽

2015 ◽

Vol 6 (6) ◽

pp. 48-52

Author(s):

Fatima Khan ◽

Sana Ali ◽

Asfia Sultan ◽

Meher Rizvi ◽

Abida Khatoon ◽

...

Keyword(s):

Methicillin Resistance ◽

Clinical Isolates ◽

Disk Diffusion ◽

Diffusion Method ◽

Clinical Failure ◽

Coagulase Negative Staphylococci ◽

Sensitivity Testing ◽

Disk Diffusion Method ◽

Methicillin Resistant ◽

Inducible Clindamycin Resistance

Introduction: Erythromycin resistant Staphylococcus isolates with inducible resistance appear sensitive to clindamycin in in?vitro sensitivity testing. If clindamycin is used for treatment of such isolates, selection for constitutive mutants may lead to clinical failure. Current study was conducted to detect the presence of inducible clindamycin resistance in erythromycin resistant Staphylococcus isolates by disk diffusion method (D test). To correlate clindamycin resistance phenotypes with minimum inhibitory concentrations (MICs) of clindamycin, erythromycin, oxacillin and vancomycin among the isolates. To correlate various resistance phenotypes with methicillin resistance. Material and Methods: 150 non duplicate isolates of Staphylococcus species were identified and antibiotic susceptibility testing was done using Kirby Bauer’s disc diffusion method. MICs were determined using E?test for oxacillin, vancomycin, clindamycin and erythromycin using E?test strips (Himedia) Results: Among 150 staphylococcus clinical isolates, 96 were of S. aureus and 54 were coagulase negative Staphylococci (CONS). About 81.2% of the S.aureus isolates and 72.2% of the CONS were found to be methicillin resistant. Inducible clindamycin resistance was found in 39.3% of the isolates, constitutive resistance phenotype in 48% while 12.7% demonstrated MS phenotype. 18% and 11.3% of all the isolates had MICs for clindamycin between 0.01?0.06 μg/ml and 0.06?0.1 respectively. 12.5% had MIC ranging from 4?8 μg/ml while 58% had MIC > 8 μg/ml. Constitutive resistant phenotype (cMLS) was the predominant phenotype in methicillin resistant isolates. MS phenotype was the predominant among MSSA (methicillin sensitive S. aureus) while MSCNS (methicillin sensitive CONS) cMLS (46.7%) predominated. MIC of all erythromycin resistant isolates were ≥ 240 μg/ml. Nearly 16.7% of the cMLS and 57.9% of MS isolates were found to be oxacillin sensitive and 83% of iMLS and 83.3% of MS phenotype isolates were oxacillin resistant on MIC testing. 47.2% of cMLS and 73.6% of MS isolates had MIC ≤ 2 μg/ml for vancomycin and 52.7% of cMLS and 26.3% of MS isolates had MICs in intermediate range for vancomycin. Conclusions: D?testing might help clinicians to decide whether to use clindamycin in Staphylococcal infections when erythromycin resistance is present. Determination of MICs help to identify exact sensitivity profile of isolates in cases where clinical failure occurs due to misleading disk diffusion tests.DOI: http://dx.doi.org/10.3126/ajms.v6i6.11811 Asian Journal of Medical Sciences Vol.6(6) 2015 48-52

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