Prevalence Of Methicillin-resistant Staphylococci Research Articles

Integrating multi-wet laboratory diagnostics to study staphylococci in animals in Uganda

BackgroundSeveral diagnostic environments in Uganda lack real-time, robust and high-throughput technologies for comprehensive typing of microbes, which is a setback to infectious disease surveillance. This study combined various wet laboratory diagnostics to understand the epidemiology of pathogenic staphylococci isolated from animals in Uganda and the implications for global health security priorities.MethodsA retrospective study was conducted employing records and pathogenic staphylococci (from animals) archived at the Central Diagnostic Laboratory (CDL), Makerere University, Uganda, between January 2012 and December 2019. The bacteria were speciated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and tested for virulence factors [beta lactamases, lecithinase, deoxyribonuclease (DNase), haemolysins] and resistance to ten antimicrobials of clinical and veterinary relevance. Tetracycline and methicillin resistance genes were also tested.ResultsThe prevalent diseases were mastitis in cattle and skin infections in dogs. Of the 111 staphylococci tested by MALDI-TOF MS, 79 (71.2%) were Staphylococcus aureus, 27 (24.3%) were Staphylococcus pseudintermedius and 5 (4.5%) were Staphylococcus schleiferi. All these strains expressed haemolysins. The prevalence of strains with lecithinase, penicillinase, cephalosporinase and DNase was 35.9% (14/39), 89.7% (35/39), 0.0% (0/39) and 87.2% (34/39), respectively. Staphylococci were primarily resistant to early penicillins (over 80%), tetracycline (57.7%), and chloramphenicol (46.2%). Minimal resistance was noted with cloxacillin (0.0%), ciprofloxacin (9.6%), and cefoxitin (3.8%). The prevalence of multidrug resistance (MDR) was 78.8% for general staphylococci, 82.2% for S. aureus, 73.1% for S. pseudintermedius, and 60.0% for S. schleiferi. Multidrug resistant staphylococci were significantly more prevalent in the cattle isolates than in the dog isolates (P < 0.05). The prevalence of methicillin-resistant staphylococci (MRS) tested by resistance to cefoxitin and mecA carriage was 3.8%. These four strains were all isolated from dog skin infections. The tetK gene was the most predominant (35.4%), followed by tetM (25.0%).ConclusionIn resource-constrained settings, the approach of integrated diagnostics promises sustainable disease surveillance and the addressing of current capacity gaps. The emergence of MRS (zoonotic bacteria) in companion animals creates a likelihood of reduced treatment options for related human infections, a threat to global health.

Microbiological characterization of neuropathic diabetic foot infection: a retrospective study at a Portuguese tertiary hospital

Diabetic foot infection imposes a significant burden and is the major cause of nontraumatic limb amputation. Adequate patient management with effective antibiotic therapy is crucial.This retrospective cohort study aimed to characterize the microbiology and resistance patterns of moderate to severe neuropathic diabetic foot infection in patients hospitalized at a tertiary referral hospital between January 2020 and June 2023. Deep tissue specimens from ulcers were collected for culture.Sixty inpatients were included (62% male, mean age 59.1 ± 11.5 years). Osteomyelitis was present in 90% of the patients. Among 102 microorganisms (average of 1.91 ± 1.25 pathogens per patient), 60.8% were gram-positive bacteria, 31.4% were gram-negative, 3.92% were anaerobic bacteria, and 3.92% were fungi. Staphylococcus aureus (19%) and Enterococcus faecium (17%) were the most common. Pseudomonas aeruginosa (8%) and bacteria of the Enterobacterales family (24%) accounted for all the isolated gram-negative bacteria. Sixteen percent of Staphylococcus aureus and 67% of coagulase-negative Staphylococci were resistant to methicillin. Resistance to ampicillin was found in 11% of Enterococci. All Pseudomonas aeruginosa isolates were sensitive to piperacillin-tazobactam, ceftazidime, or cefepime. Among the Enterobacterales, resistance rates were 35% for piperacillin-tazobactam, 38% for ceftazidime, 21% for cefepime, and 13% for carbapenems.Although the prevalence of methicillin-resistant staphylococci was lower than that in other studies, carbapenem resistance among gram-negative bacteria warrants attention. This study highlights the importance of understanding local epidemiology for effective diabetic foot infection management and resistance mitigation.

Studying Microbial Ecology of Diabetic Foot Infections: Significance of PCR Analysis for Prudent Antimicrobial Stewardship.

This study presents a comprehensive investigation into the microbial ecology of diabetic foot infections (DFIs), using molecular-polymerase chain reaction (PCR) analysis to accurately identify the causative agents. One hundred DFI patients were recruited and classified using the Depth Extent Phase and Associated Etiology (DEPA) score according to their severity. Results revealed polymicrobial infections in 75% of cases, predominantly featuring Staphylococcus epidermidis (83%) and Staphylococcus aureus (63%). Importantly, 20% of samples exhibited facultative anaerobes Bacteroides fragilis or Clostridium perfringens, exclusively in high DEPA score ulcers. Candida albicans coinfection was identified in 19.2% of cases, underscoring the need for mycological evaluation. Empirical antimicrobial therapy regimens were tailored to DEPA severity, yet our findings highlighted a potential gap in methicillin-resistant Staphylococcus aureus (MRSA) coverage. Despite an 88% prevalence of methicillin-resistant Staphylococci, vancomycin usage was suboptimal. This raises concerns about the underestimation of MRSA risk and the need for tailored antibiotic guidelines. Our study demonstrates the efficacy of molecular-PCR analysis in identifying diverse microbial communities in DFIs, influencing targeted antibiotic choices. The results advocate for refined antimicrobial guidelines, considering regional variations in microbial patterns and judiciously addressing multidrug-resistant strains. This research contributes crucial insights for optimizing DFIs management and helps the physicians to have a fast decision in selection the suitable antibiotic for each patient and to decrease the risk of bacterial resistance from the improper use of broad-spectrum empirical therapies.

Low prevalence of bacteria harbouring the main transferable genes coding for β-lactams resistance in ovine bulk tank milk produced in Central Italy

Sheep farming for milk production is an important sector of the Italian agricultural industry. Italy has a significant annual sheep milk production, which amounted to 477.000 ton in 2021 and almost exclusively employed for cheeses production. The aim of this work was to evaluate the prevalence of beta-lactams-resistant bacteria (methicillin-resistant staphylococci and Gram-negative bacteria) in bulk tank ovine milk collected from 97 farms located in central Italy (Tuscany and Lazio). Samples were screened for the presence of resistant microorganisms employing selective media, bacteria were identified by 16 S rRNA gene sequencing and tested for susceptibility for different beta-lactams (penicillins, carbapenems, cephalosporins, as well as beta lactams association with beta-lactamase inhibitors). Resistant microorganisms were subjected to PCR for the detection of the main transferable gene coding for beta-lactams resistance mechanisms spread among Gram-positive and Gram-negative bacteria. A low prevalence of methicillin resistant staphylococci (4%) and methicillin resistant Staphylococcus aureus (1%) in bulk tank milk from sheep herds raised in Central Italy was highlighted. This resistance was related to the presence of mecA gene in S. aureus and coagulase negative staphylococci. All the tested samples resulted negative for the presence of bacteria able to produce carbapenemases or ESBLs due to the presence of some of the main mobile genetic determinants in their genomes and targeted in this study. Most of the phenotypic resistance observed were instead related to the common presence of psychrotrophic bacteria in bulk tank milk belonging to Stenothrophomonas spp. which harboured L1 and L2 genes coding for inducible β-lactamases located on the bacterial chromosome. In conclusion, a low prevalence of bacteria resistant to β-lactams due to the presence of horizontally transferable genes was detected, suggesting a low selective pressure for resistant microrganisms whitin this farming system.

Methicillin-Resistant Staphyloccocus aureus Contamination in Hospital Door Handles of Pokhara, Nepal

The presence of contaminants on the door handles surfaces of hospitals may be a common means of transfer of potentially pathogenic bacteria among users and can act as vehicles of diseases transmission. The aim of this study was to isolate, identify and evaluate the presence of bacterial contaminants and Methicillin Resistant Staphylococci (MRSA) with their antimicrobial susceptibility pattern present on the door handles of selected hospitals of Pokhara Metropolitan City, Western Nepal to take the necessary remedial measures. Isolation, identification and antimicrobial susceptibility test of bacteria were done using standard microbiological procedures. Further screening and confirmation of MRSA were done according to Clinical Laboratory Standard Institutes (CLSI) guidelines. Out of the 100 swab samples cultured, 96 (96%) showed bacterial growth. 62.86% (88/140) of the isolates were found to be Gram positive. Percentage distribution of the isolates showed that the most prevalent Gram-positive bacteria identified was Staphylococcus aureus (43.18%), followed by Coagulase negative Staphylococci (15.91%), Bacillus spp (11.36%), Diptheroides (10.23%) but considerable number of Micrococci (7.95%), Streptococcus pneumoniae (6.82%), Enterococci (4.55%). Prevalence of MRSA in this study was 39.47%. Significant difference in antibiotic resistance pattern was found among MRSA and MSSA isolates (P&lt;0.05) reflecting increased ability of MRSA to develop resistance against various antimicrobials. Drugs like clindamycin, cefazoline and amikacin were found quite effective against MRSA in the present study would be better options for the management of such infections. MRSA strains’ contaminating on the door handles of hospitals may cause threat of infections to patients, hospital staffs, visitors to hospitals and people in the community. Thus, regular surveillance and disinfection with appropriate agent at regular interval would minimize the settlement and transmission of various pathogens including MRSA.Keywords: Contaminants; disinfection; door handles; hospital; MRSA; pathogen

Occurrence of methicillin-resistant staphylococci in the pig-production chain in Ibadan, Nigeria.

Staphylococcus species colonises humans and animals and is a major food contaminant with public health significance. Here, we assessed the occurrence of methicillin-resistant staphylococci (MRS) in the pig-production chain in Ibadan, Nigeria. Nares of 120 pigs and 10 farmers were sampled with sterile swabs whilst 54 pork samples were collected from a retail slaughterhouse. Staphylococcus species were isolated using enrichment, cefoxitin–aztreonam selective broth and Mannitol salt agar. Isolates were tested for susceptibility to cefoxitin (30 μg), oxacillin (1 μg) and vancomycin (30 μg). Methicillin-resistant staphylococci isolates were characterised using conventional biochemical tests. From 184 samples, 364 staphylococcal isolates were obtained. Amongst the 54 pork samples, 44.0% were contaminated with Staphylococcus species. Overall, 9 (2.5%) MRS were obtained and presumptively identified as Staphylococcus xylosus (n = 3), Staphylococcus sciuri (n = 3), Staphylococcus warneri (n = 2) and Staphylococcus cohnii (n = 1). There was no relationship between the prevalence of MRS between pigs and pig handlers in the farms, but Farm 2 had the highest frequency of 66.7% (p < 0.05). Piglets had the highest prevalence of 66.7% (p < 0.05) whilst MRS was absent in workers and pork samples. This study raises concerns about the cross-contamination of staphylococci in the food chain. Constant surveillance is imperative to ensure food safety.

Characterization of staphylococci sampled from diabetic foot ulcer of Jordanian patients.

The aim of this study was to isolate and characterize staphylococcal isolates from diabetic foot ulcers (DFU) in Jordanian patients. Selected aerobic pathogens recovered from DFU specimens and patients' nares with a focus on staphylococci were investigated. Antimicrobial susceptibilities and the prevalence of methicillin-resistant staphylococci (MRS) were determined. SCCmec types and toxigenic characteristics were analysed and spa typing was performed for methicillin-resistant Staphylococcus aureus (MRSA) isolates. The relationship between toxigenic characteristics of MRSA and the Wagner ulcer grading system was statistically analysed. A total number of 87 DFU patients were recruited for the study. The DFU cultures were polymicrobial. Members of the genus Staphylococcus were the most common among DFU-associated isolates found in 48·3% (n=42) of all patients enrolled. Coagulase-negative staphylococci (CoNS) comprised 63·3% of staphylococci isolated from DFUs predominated by Staphylococcus epidermidis in both DFU (7·6%) and nares (39·2%). Staphylococcus aureus was isolated from DFUs and nares in 14·2 and 9·8%, respectively, while 93 and 70% of these isolates were MRSA. Most of MRSA carried SCCmec type IV (76·2%) while SCCmec elements were non-typeable in most methicillin resistant coagulase negative staphylococci (MR-CoNS) (61·9%). The most frequent MRSA spa type was t386 (23·8%). Most MRSA and MR-CoNS exhibited resistance towards aminoglycosides, fluoroquinolones and macrolides and susceptibility towards vancomycin, mupirocin and linezolid. No association was found between the possession of pvl, tst, sea and hlg toxins and Wagner ulcer grading system (P value >0·05). This analysis of Jordanian DFU culture demonstrated its polymicrobial nature with predominance of Staphylococcus sp. This study is the first of its type to assess the microbiology of DFU among Jordanian patients. The results will help in the appropriate application of antimicrobial chemotherapy in the management of DFU.

Prevalence and antibiogram of coagulase negative Staphylococci in bioaerosols from different indoors of a university in India

BackgroundStaphylococci species are the major constituents of infectious bioaerosols, particularly methicillin-resistant Staphylococci (MRS) have serious health impacts. Here, the bacterial burden was quantified, especially prevalence of MRS in bioaerosols collected from indoors of Dr. B.R. Ambedkar Central Library (DBRACL) and Central Laboratory Animal Resources (CLAR) of Jawaharlal Nehru University, New Delhi, India. Air samplings from DBRACL and CLAR were done using the settle plate method and SKC biosampler, respectively.ResultsThis study showed a maximum 6757 CFU/m2/hr of bacterial load in the DBRACL reading room, while unacceptable bacterial loads (> 1000 CFU/m3 of air) at different sites of CLAR. Further, at both the sampling sites the predominance of coagulase negative Staphylococci (CNS) was observed. A total 22 and 35 Staphylococci isolates were isolated from DBRACL and CLAR bioaerosols, respectively. Majority (16/22) of the Staphylococcal isolates from DBRACL belonged to human-associated Staphylococci where S. haemolyticus (5/22) was the most dominating species. However, in CLAR facility centre, animal-associated Staphylococci (19/35) were dominating, where S. xylosus (12/35) was the most dominating species. Further, antibiotic sensitivity tests revealed 41% MRS and 73% multidrug resistant (MDR) among airborne Staphylococci from DBRACL indoor bioaerosols. Similarly, in CLAR facility, approximately, 66% Staphylococci isolates were methicillin resistant, out of which 2 isolates showed high MIC value ≥ 16 μg/mL. Further, we confirmed the presence of 49% multidrug resistant Staphylococci in the indoor air of CLAR facility.ConclusionsThis study suggested that the exposure of workers and students in CLAR to such a high concentration of drug-resistant Staphylococci should not be undermined, as these bacterial concentrations are the direct representative of inhalable particulate matter (PM2.5) as per collection procedure. Simultaneously, passive sampling from DBRACL assessed the risks due to microbial contamination in particle agglomerates, which may deposit on the crucial surfaces such as wounds/ cuts or on the frequently used items.

Prevalence Of Methicillin-Resistant Staphylococci Among Apparently Healthy Students Attending A Tertiary Institution In Benin City, Nigeria

This study was aimed at determining the prevalence of methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase negative staphylococci (MRCoNS) among apparently healthy students of a tertiary institution in Benin City, Nigeria. A total of 350 students were recruited for the study and nasal swabs were collected alongside demographic data. These swabs were processed microbiologically using standard techniques to recover staphylococci. Antimicrobial susceptibility and methicillin-resistance was determined using a phenotypic method (cefoxitin resistance). A total of 148 (42.3%) of 350 students were culture positive for S. aureus, while 72 (20.6%) were positive for CoNS. Students from Faculty of Dentistry showed the highest prevalence of nasal MRSA (40.0%) and MRCoNS (20.0%). Ofloxacin and gentamicin were the most active antibacterial agents against MRSA with 89.1% and 87.3% respectively been susceptible, while gentamicin was the most active antibiotic against MRCoNS (75.0%). Nasal colonization by MRSA and MRCoNS was unaffected by area of residence and gender (P &gt; 0.05). The nasal carriage rate of MRSA and MRCoNS was 37.2% and 33.3% respectively. The study recommends periodic review of nasal colonization rates among apparently healthy subjects. Regulated use of antimicrobial agents is imperative in order to stem the tide of resistance.&#x0D; Keywords: Methicillin-resistance, Staphylococci, Students, Antibiotics

Methicillin resistance gene diversity in staphylococci isolated from captive and free-ranging wallabies

BackgroundInfection with methicillin-resistant staphylococci (MRS) can be life-threatening in humans and its presence in animals is a cause for public health concern. The aim of this study was to measure the prevalence of MRS in captive and free-ranging wallabies over a 16-month period in South Australia, Australia.Materials and methodsEighty-nine purified staphylococcal isolates recovered from 98 captive and free-ranging wallabies' anterior nasal swabs were used in this study. All isolates were tested for the presence of the mecA, mecA1, and mecC genes. Multiplex PCR-directed SCCmec-typing, ccrB-typing, and determination of the minimal inhibitory concentration of oxacillin were performed on mec-positive isolates.Results and discussionIn total, 11 non-Staphylococcus aureus MRS were isolated from 7 out of 98 animals, corresponding to a 7.1% carriage rate. The SCCmec types I, III, and V were identified by multiplex PCR and sequencing of the ccrB gene. This is the first report of MRS carriage in both captive and free-ranging wallabies in Australia. These data demonstrate a low prevalence of MRS and no association between wallaby captivity status and MRS carriage could be assigned. These animals may act as a reservoir for the exchange of genetic elements between staphylococci. Furthermore, the mecA genes of animal isolates were identical to that found in human MRS strains and thus the possibility of zoonotic transfer must be considered.

Isolation and Characterisation of Multi-Drug Resistant Coagulase Negative S.schleiferiSubsp Schleferi from a Case of Recurrent Pyoderma in Canine

Recurrent pyoderma is a chronic-relapsing clinical condition which is mostly associated with inappropriate use of antibiotics. Methicillin-resistant staphylococci are most frequent microorganisms associated with canine pyoderma and other soft tissue infections. Prevalence of methicillin-resistant staphylococci has shown an increasing trend as a cause of canine pyoderma in recent years. Coagulase positive staphylococci were predominantly reported in canine pyoderma cases until recent times. The present study describes the isolation and characterisation of multi-drug resistant coagulase negative Staphylococcus from a case of recurrent pyoderma in canine. The isolate was confirmed by the growth on selective media and other biochemical tests. Antibiotic sensitivity assay confirmed the isolate to be multidrug resistant with multiple antibiotic resistance index (MARI) of >0.9. The molecular methods based on 16s rRNA, coagulase, Nuc and MecA genes further confirmed phenotypic observations. The multidrug resistance, including antibiotics, which are not commonly used in animal practice in this region, suggests the event of either new host adoption or acquiring antibiotic resistance through lateral transfer from human isolates.

Prevalence of Methicillin Resistant Staphylococcal Bioaerosols in and around Residential Houses in an Urban Area in Central India.

Methicillin resistant staphylococci (MRS) commonly found in clinical samples or associated environment pose a major health challenge globally. The carriage rate of MRS in human population is high, especially in India but research on airborne distribution of MRS is scanty. The present study aimed to evaluate the prevalence of MRS in indoor and outdoor environment of residential houses. Air samples were collected using impactor air sampler. The total counts of viable bacteria, staphylococci, and MRS along with the particles of various sizes were determined from indoor and outdoor environment of 14 residential houses. MRS bacteria were identified as methicillin resistant S. aureus (MRSA) or coagulase negative staphylococci (CNS) employing biochemical and PCR assays. The average concentration of MRS inside and outside of the houses was 5.9% and 4.6% of the total bacteria, respectively. The maximum correlation of total indoor and outdoor bacteria with particulate matter was 10 μm (r = 0.74) and 5 μm (r = 0.84), respectively. Statistically, significant positive correlation of staphylococci and MRS was found with particles of 10–25 μm inside the houses. Molecular surveillance, antibiotic stewardship programme, and infection control policies can help to manage increasing MRS burden in developing countries.

Antibiotic Susceptibility and Molecular Identification of Antibiotic Resistance Genes of Staphylococci Isolated from Bovine Mastitis in Algeria

The study aimed to investigate the phenotypic and genotypic identification of in vitro antimicrobial susceptibility of 21 Staphylococci (10 Staphylococcus aureus and 11 Coagulase Negative Staphylococci) isolated from bovine mastitis to 12 antimicrobial drugs frequently using in veterinary medicine in Algeria. Isolates of staphylococci from bovine mastitis were tested for antibiotics with disc-diffusion method according to the National Committee for Clinical Laboratory Standards guidelines in the Mueller-Hinton agar, and resistant genes mecA, blaZ, aac-aph, ermA, ermC, tetK and tetM were detected by PCR. Staphylococci isolates showed high resistance to penicillin (95.23%), oxacillin (80.95%), clindamycine (80.95%), and erythromycin (76.19%) but, no resistance in all these strains was detected for gentamicin. Among 21 isolates of Staphylococci, 20 were found to be methicillin and multidrug resistant. Multidrug resistant strains exhibited several antibiogram patterns (antibiotic I to XIII). The distribution of antibiotic-resistant genes was mecA (100%) and tetM (100) followed by blaZ (42.85%). In the present study, the significant determination was the high prevalence of methicillin-resistant Staphylococci, which were resistant to multiple antibiotics. The finding of methicillin-resistant staphylococci from bovine mastitis is the first report in Algeria and revealed the status of resistant isolates in herd that might be helpful in treatment, controlling of resistant strains and for deciding culling of cows.

PHENOTYPIC AND GENOTYPIC DETECTION OF METHICILLIN- RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) IN BROILER CHICKENS

Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly reported as emerging problem in veterinary medicine, particularly in small animals and poultry. In Egypt, there is limited information on MRSA carriage in poultry. So the aim of this study was to investigate the prevalence of methicillin resistant staphylococci specifically MRSA in commercial broilers using both phenotypic and genotypic methods. A total of 87 (72.5%) staphylococcal strains were isolated from 120 broiler chicken samples. Out of 87 isolates, 10 (11.5%) were isolated from healthy chickens while the rest 77 (88.5%) were recovered from diseased and dead chickens. Identification of these isolates was performed using combined phenotypic and genotypic methods. Phenotypic identification classified the Staphylococcal isolates into coagulase positive (CPS) and coagulase negative Staphylococci (CNS). Out of 87 staphylococcal strains 37(42 .5%) were coagulase positive Staphylococci (CPS) while 50 (57.5%) were coagulase negative Staphylococci (CNS). Studying the antibiotic Susceptibility profile of 37(CPS) staphylococcal strains against 12 antimicrobial agents revealed that the highest rate of resistant of staphylococcal species was observed to Ampicillin; Methicillin; Gentamicin and Trimethoprim-sulfamethoxazole (100%) while the highest rate of sensitivity was 59.5, 40.5, 29.7 and 21.6 % for Vancomycin; Doxycycline; Streptomycin and Ciprofloxacin, respectively. Genotypic identification of twenty representative coagulase positive Staphylococcus isolates was performed using multiplex PCR assay. All the twenty isolates were found to be Staphylococci by successful amplification of the 228 bp PCR product of the Staphylococcal specific 16S rRNA gene. Simultaneously, 12 out of them were confirmed to be S. aureus by successful amplification of 279 bp PCR product of the S. aureus specific thermonuclease gene while the rest of isolates were identified to be staphylococci other than S. aureus. All the confirmed S. aureus isolates in addition to 5 non S. aureus strains were confirmed to be methicillin resistant through successful amplification of 147 bp specific products. In Conclusion, this study shows high incidence of methicillin resistant among staphylococci and specifically MRSA in broiler chickens including both healthy and diseased ,dead birds in Assiut Governorate, Egypt.

Prevalence of methicillin-resistant staphylococci in northern Colorado shelter animals

Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus pseudintermedius (MRSP) have been recognized as significant pathogens in veterinary medicine. There have been documented cases of MRSA infection and colonization in veterinary critical care units, in veterinary personnel, and in equine and feline patients. To date, there have been no studies examining the prevalence of MRSA or MRSP colonization of cats and dogs in animal shelters in the United States. The purpose of the current study was to determine the prevalence of MRSA and MRSP in cats and dogs in a northern Colorado animal shelter. Samples were collected from 200 cats and 200 dogs in an open admission shelter. Each species was divided into 2 smaller groups: 100 dogs or cats housed in the stray ward and 100 dogs or cats housed in the adoption area. Samples were evaluated for the prevalence of MRSA or MRSP, which was verified through aerobic culture and Kirby-Bauer agar disc diffusion to confirm antimicrobial sensitivity. Results revealed MRSA in 0.5% of cat samples, MRSA in 0.5% of dog samples, and MRSP in 3% of dog samples. These results are consistent with previously published prevalence rates for these 2 organisms in non-shelter populations of dogs and cats, indicating that cats and dogs from this Colorado shelter do not appear to pose any greater risk to the public than do cats and dogs in the general pet population.

Antimicrobial resistance surveillance of gram-positive cocci isolated from 12 teaching hospitals in China in 2008

Objective To investigate antimicrobial resistance among gram-positive cocci in China in 2013. Methods Retrospective study. From June 2013 to December 2013, 1 663 consecutive and non-repetitive gram-positive cocci were collected from 15 teaching hospitals. The minimal inhibitory concentration (MIC) of antibacterial agents was determined by agar dilution method. A retrospective study was conducted on rates of resistance to antimicrobial agents. The prevalence of penicillin-resistant Streptococcus pneumoniae (PRSP) between children and adult patients and the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) between elder group and younger adult patients were compared using chi-square test. Results The prevalence of PRSP in children below 3 years old (72.9%, 51/70) was higher than adult patients (55.2%, 106/192) (χ2=6.653, P<0.05). About 94.9% (261/275) and (92.7%, 255/275) of S. pneumonia were resistant to erythromycin and clindamycin. All S. pneumoniae strains were susceptible to teicoplanin, vancomycin, linezolid, tigecycline and daptomycin. Penicillin still showed very high activity against Streptococcus spp. β-Hemolytic group. More than 60% of Streptococcus spp.β-Hemolytic group were resistant to erythromycin, clindamycin and tetracyclines. The prevalence of MRSA and methicillin-resistant coagulase-negative Staphylococci(MRCoNS) was 39.7%(229/576) and 80.6%(224/278), respectively. The MRSA prevalence ranged from 24.2% to 70.0% in different regions. About 52.6% (100/190) of Staphylococcus aureus from respiratory tract specimens, 38.5% (40/104) of Staphylococcus aureus from blood samples, and 29.7%(58/195)of Staphylococcus aureus from wound and pus were resistant to methicillin. The prevalence of MRSA in elder group (48.6%, 84/173) was higher than that in younger adult patients (35.7%, 144/403) (χ2=8.322, P<0.05). The susceptibility rates of MRSA to chloramphenicol and trimethoprim/sulfamethoxazole were 86.4% (244/228) and 94.7% (237/228), respectively. Susceptibility rates to gentamycin, erythromycin, clindamycin, tetracyclines, rifampicin and quinolones were ranged from 15.8% to 59.6%. All Staphylococci isolates were susceptible to teicoplanin, vancomycin, linezolid, daptomycin and tigecycline. All Enterococcus isolates were susceptible to daptomycin and tigecycline. All E. faecalis (158/158) and 96.4% (133/138) of E. faecium were susceptible to teicoplanin. About 98.0% (150/153) of E. faecalis and 97.1% (145/138) of E. faecium were susceptible to linezoild. About 45.8% (70/153) of E. faecalis and 60.9% (84/138) of E. faecium were resistant to gentamycin with a high concentration. The susceptibility of E. faecalis to all the antibiotics tested except chloramphenicol and tetracycline was higher than that of E. faecium. Conclusions Based on different age groups and regions, the resistance rates of Gram-positive cocci are different. Teicoplanin, vancomycin, tigecycline, daptomycin, linezolid and tedizolid showed very high activity against Gram-positive cocci.(Chin J Lab Med, 2015, 38: 373-381) Key words: Gram-positive cocci; Drug resistance, bacterial; Anti-bacterial agents; Microbial sensitivity tests; Multicenter study

The prevalence of methicillin-resistant staphylococci in healthy horses in the Netherlands

Two hundred healthy horses housed at 23 different farms and one clinic and 42 persons in close contact with these horses were screened for the presence of methicillin resistant staphylococci. Samples were taken from the nose and the pastern of the horses and from the nose and throat of the humans and incubated in selective media. Isolates were identified by standard techniques and their susceptibilities were tested using an agar diffusion method. Methicillin-resistant strains were tested for the presence of the mecA gene by PCR. In 45 horses (22.5%) and 15 humans (35.7%) mecA positive staphylococci were found. All isolates were coagulase negative staphylococci, except for one methicillin-resistant Staphylococcus aureus isolated from a veterinarian. Staphylococcus sciuri was the predominant species found among the methicillin resistant staphylococci (MRS) in the horses, whereas S. epidermidis predominated in the humans. From the horses, often more than one species of MRS could be isolated, resulting in a total of 175 mecA positive equine isolates. The equine isolates were predominantly susceptible to most antimicrobials tested, whereas the human isolates showed more resistance. In conclusion, no methicillin-resistant Staphylococcus aureus was found in healthy horses in the Netherlands, but methicillin-resistant coagulase negative staphylococci were found frequently. Further studies are needed in order to investigate whether horses can be a reservoir for MRS or the mecA gene for humans.

MRSA--past, present, future

Infections with methicillin-resistant staphylococci (MRSA) remain a major concern. A Medline search reveals 175 publications in the past eight weeks and the BMJ has produced two editorials in the space of a year.1,2 For the reason, readers need look no further than the article by Dr David Thompson on p. 521.3 In the intensive care unit (ICU) of his hospital, MRSA were present for 16.9% of available bed-days.

Methicillin-resistant staphylococci in clean surgery. Is there a role for prophylaxis?

The incidence of infection in clean surgery (i.e. surgery with no major contamination of the operative site) should be less than 2%, although the incidence of postoperative infections can be higher in patients with various risk factors (namely insertion of foreign bodies, a compromised immune status or prolonged duration of surgery). Although antibiotic prophylaxis has been shown to reduce the incidence of postoperative infections in clean surgery, there is still no consensus regarding its use in this area. However, for clean surgical procedures that involve implantation of foreign material, grafts or prosthetic devices, prophylaxis is well accepted and justifiable, since this practice is indicated when the benefits exceed the expected risks. Staphylococcus aureus and coagulase-negative staphylococci are responsible for 70 to 90% of wound infections in this type of surgery. First and second generation cephalosporins are considered the drugs of choice for surgical prophylaxis. Cefazolin and other cephalosporins have good tissue penetration but poor coverage against methicillin-resistant staphylococci. The frequency with which methicillin-resistant staphylococci have been recovered in nosocomial infections has increased steadily during recent years. This provides a rationale for the use of alternative antibiotics, such as the glycopeptides (vancomycin and teicoplanin), for prophylaxis in clean surgery in hospitals where the prevalence of methicillin-resistant staphylococci is high. The effectiveness and tolerability of teicoplanin as prophylaxis for orthopaedic surgery involving joint replacement were analysed in 4 randomised controlled trials. Two compared teicoplanin with cefamandole, while the others compared teicoplanin with either cefuroxime or cefazolin. The overall early wound infection rates (within 3 months) in these studies were 1.1% for teicoplanin and 1.7% for the comparator cephalosporin. The overall late infection rate was 0.2% for both treatment groups. Adverse events were attributed to the drug in 1% of patients in both treatment groups. Therefore, on the basis of these trials, single dose teicoplanin is as efficacious and as well tolerated as multiple dose cephalosporin regimens for prophylaxis in prosthetic joint surgery.

Prevalence of methicillin-resistant staphylococci and susceptibility to antimicrobial agents in Riyadh, Saudi Arabia

Surveillance data reported by hospitals participating in this study demonstrated that 5% of Staphylococcus aureus and 35% of Staphylococcus epidermidis isolates were resistant to methicillin. Two hundred clinical isolates of methicillin-resistant staphylococci (MRS) (100 each of S aureus and S epidermidis) were tested for susceptibility to 16 antimicrobial agents by the disk diffusion technique as recommended by the National Committee for Clinical Laboratory Standards. The isolates showed a high frequency of resistance to tetracycline and aminoglycosides. The incidence of resistance was higher in S aureus than in S epidermidis, especially for beta-lactam antibiotics and aminoglycosides. All isolates were susceptible to vancomycin, and only 3% of methicillin-resistant S aureus (MRSA) and 2% of methicillin-resistant S epidermidis (MRSE) were resistant to fucidin whereas 90% of MRSA and 82% of MRSE were resistant to gentamicin. Most of the MRSE isolates were susceptible to cefamandole and cephalothin but few were susceptible to ceftriaxon.