Distribution of pathogenic Leptospira in environmental water and soils of selected recreational forests in Perak, Malaysia.

Leptospirosis is an emerging zoonotic disease endemic in tropical regions. Aiming at assessing the potential infection risks via recreational exposure, the molecular prevalence of pathogenic Leptospira in 14 amenity forests in five selected districts of the state of Perak was determined. Water and soil samples along streams and waterfalls were subjected to culture of leptospires and the pathogenic Leptospira spp. was detected by lipL32-based polymerase chain reaction (PCR). Twenty out of 154 samples (13%) that tested positive for leptospires were mostly soils and still water recorded with tolerable temperatures (22.2- 26.5°C) and pHs (5.73-6.70). The localised prevalence was highly varied among eight positive forests (6.7-41.7%), particularly higher in Kampar and Kinta districts which are the more populated urban areas. The importance of public health surveillance should not be underrated given the high prevalence of Leptospira spp. in forests in close proximity to indigenous settlements, even where the places are clean. Overall, this study discovered a wide distribution of pathogenic Leptospira spp. in recreational areas.

Distribution of pathogenic Leptospira in environmental water and soils of selected recreational forests in Perak, Malaysia

@#Leptospirosis is an emerging zoonotic disease endemic in tropical regions. Aiming at assessing the potential infection risks via recreational exposure, the molecular prevalence of pathogenic Leptospira in 14 amenity forests in five selected districts of the state of Perak was determined. Water and soil samples along streams and waterfalls were subjected to culture of leptospires and the pathogenic Leptospira spp. was detected by lipL32-based polymerase chain reaction (PCR). Twenty out of 154 samples (13%) that tested positive for leptospires were mostly soils and still water recorded with tolerable temperatures (22.226.5°C) and pHs (5.73-6.70). The localised prevalence was highly varied among eight positive forests (6.7-41.7%), particularly higher in Kampar and Kinta districts which are the more populated urban areas. The importance of public health surveillance should not be underrated given the high prevalence of Leptospira spp. in forests in close proximity to indigenous settlements, even where the places are clean. Overall, this study discovered a wide distribution of pathogenic Leptospira spp. in recreational areas.

Leptospirosis: An insight into community structure of small mammal's host in urban environment.

Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira and most often acquired through contact with environments contaminated with leptospires shed in the urine of infected mammals. In urban environment, rodents are well-known as the main carriers of this bacteria, however there were no intensive study on the population structure of these animals, and how it associated with this disease. Hence, we use a case study from an outbreak in a residential area in Selangor, Malaysia, to investigate how community structure of small mammals, associated with the prevalence of Leptospira. One hundred cage traps were placed randomly in and around these houses in five phases with two months interval for a year. Community structures (species, sex, and age) were assigned for each individual, prior to screening for pathogenic Leptospira, using a partial lipL32 gene from the kidney samples. 185 small mammals from four species were captured, Rattus norvegicus (74.5%, N=138), R. rattus (20%, N=37), Tupaia glis (5%, N=9), and Suncus murinus (0.5%, N=1). From this number, 29 individuals were found PCR positive for pathogenic Leptospira (R. norvegicus, N=20; R. rattus, N=6; T. glis, N=2; S. murinus, N=1). The study shows that Leptospira occurrence in the small mammals were significantly correlated to age category and sampling phases, with Spearman Correlation (rs) p=0.02 and p=0.04 respectively. Adult individuals were significantly more prevalent with Leptospira infection, whereby March and June were found to associate with higher Leptospira prevalent among the small mammals, potentially coincide with low rainfall and relative humidity level. This information is important in designing a specific control method for rodents in Leptospira outbreak areas. In addition, intensive sampling and regular cleaning effort were found to significantly reduce the small mammal Leptospira reservoir, thus should be implemented in intervention strategies in the urban environment.

Time-kill and post-antibiotic effect of colistin at different static concentrations in in vitro Acinetobacter baumannii.

Nosocomial infection caused by Acinetobacter baumannii is common among immunocompromised patients. Treatment strategy is limited due to rapid resistance development and lack of novel antibiotic. Colistin has been the last line therapy with good in vitro activity against infections caused by multi-drug resistance A. baumannii. However, pharmacological updates are required to support dosing optimisation. This study aimed to determine the time-kill kinetic and resistance development after antibiotic exposure as well as post-antibiotic effect of colistin at different static concentrations in in vitro A. baumannii system. The static in vitro time-kill and post-antibiotic effect experiments were conducted against two clinical isolates as well as one reference isolate ATCC 19606. Time-kill and postantibiotic effect were studied at colistin concentrations ranging from 0.25MIC to 16.0MIC and 0.5MIC to 4.0MIC, respectively. Post-exposure resistance development was examined in time-kill study. Killing activity and post-antibiotic effect were in a concentration-dependent manner. However, delayed killing activity indicates colistin tolerance. Development of resistance after exposure was not detected except for the ATCC 19606 strain. Dosing suggestion based on the observations include administration of supplemental dose 3 MIU at 12 hours after loading dose, administration of maintenance dose 9 MIU in two divided doses and application of extended interval in renal adjustment dose. However, the information is applicable for non-colistin-heteroresistance A. baumannii with colistin MIC < 1.0 mg/L. As for heteroresistance and strain with colistin MIC > 1.0 mg/L, combination therapy would be the more appropriate treatment strategy.

Time-kill and post-antibiotic effect of colistin at different static concentrations in in vitro Acinetobacter baumannii

@# Nosocomial infection caused by Acinetobacter baumannii is common among immunocompromised patients. Treatment strategy is limited due to rapid resistance development and lack of novel antibiotic. Colistin has been the last line therapy with good in vitro activity against infections caused by multi-drug resistance A. baumannii. However, pharmacological updates are required to support dosing optimisation. This study aimed to determine the time-kill kinetic and resistance development after antibiotic exposure as well as post-antibiotic effect of colistin at different static concentrations in in vitro A. baumannii system. The static in vitro time-kill and post-antibiotic effect experiments were conducted against two clinical isolates as well as one reference isolate ATCC 19606. Time-kill and postantibiotic effect were studied at colistin concentrations ranging from 0.25MIC to 16.0MIC and 0.5MIC to 4.0MIC, respectively. Post-exposure resistance development was examined in time-kill study. Killing activity and post-antibiotic effect were in a concentration-dependent manner. However, delayed killing activity indicates colistin tolerance. Development of resistance after exposure was not detected except for the ATCC 19606 strain. Dosing suggestion based on the observations include administration of supplemental dose 3 MIU at 12 hours after loading dose, administration of maintenance dose 9 MIU in two divided doses and application of extended interval in renal adjustment dose. However, the information is applicable for non-colistin-heteroresistance A. baumannii with colistin MIC < 1.0 mg/L. As for heteroresistance and strain with colistin MIC > 1.0 mg/L, combination therapy would be the more appropriate treatment strategy.

Leptospirosis: An insight into community structure of small mammal’s host in urban environment

@#Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira and most often acquired through contact with environments contaminated with leptospires shed in the urine of infected mammals. In urban environment, rodents are well-known as the main carriers of this bacteria, however there were no intensive study on the population structure of these animals, and how it associated with this disease. Hence, we use a case study from an outbreak in a residential area in Selangor, Malaysia, to investigate how community structure of small mammals, associated with the prevalence of Leptospira. One hundred cage traps were placed randomly in and around these houses in five phases with two months interval for a year. Community structures (species, sex, and age) were assigned for each individual, prior to screening for pathogenic Leptospira, using a partial lipL32 gene from the kidney samples. 185 small mammals from four species were captured, Rattus norvegicus (74.5%, N=138), R. rattus (20%, N=37), Tupaia glis (5%, N=9), and Suncus murinus (0.5%, N=1). From this number, 29 individuals were found PCR positive for pathogenic Leptospira (R. norvegicus, N=20; R. rattus, N=6; T. glis, N=2; S. murinus, N=1). The study shows that Leptospira occurrence in the small mammals were significantly correlated to age category and sampling phases, with Spearman Correlation (rs) p=0.02 and p=0.04 respectively. Adult individuals were significantly more prevalent with Leptospira infection, whereby March and June were found to associate with higher Leptospira prevalent among the small mammals, potentially coincide with low rainfall and relative humidity level. This information is important in designing a specific control method for rodents in Leptospira outbreak areas. In addition, intensive sampling and regular cleaning effort were found to significantly reduce the small mammal Leptospira reservoir, thus should be implemented in intervention strategies in the urban environment.

Seroprevalence of leptospiral antibodies among market workers and food handlers in the central state of Malaysia.

OBJECTIVE: The high prevalence of leptospirosis in humans is of great public health concern, particularly in tropical and subtropical regions. This study aimed to determine the seroprevalence of leptospiral antibodies and distribution of serovars, and to assess the usefulness of enzyme-linked immunosorbent assay (ELISA) as a screening method for leptospiral antibodies in a high-risk healthy community. METHODS: Cross-sectional study of 231 market workers and food handlers in wet markets and food premises from two localities in central Malaysia. Respondents' background information was obtained using a questionnaire. Serum samples were tested for leptospiral antibodies using ELISA and microscopic agglutination test (MAT). RESULTS: Seroprevalence of leptospirosis among healthy workers was 46.3%. Detection of seropositivity was higher by MAT (46%) than ELISA (15%). We observed high seropositivity among local workers (49%), food handlers (49.5%), females (60.8%) and those aged 34 years and older (46.3%). Local strain LEP175 was the predominant serovar, followed by WHO strain Patoc. CONCLUSION: Overall seroprevalence among healthy food handlers and market workers was high in this study. The workplace places susceptible individuals at risk of leptospirosis.

Humoral immune consequences of Staphylococcus aureus ST239-associated bacteremia.

The humoral immune responses against 46 different staphylococcal antigens in 27 bacteremia patients infected by clonally related methicillin-resistant Staphylococcus aureus (MRSA) strains of a single sequence type (ST) 239 were investigated. A group of non-infected patients (n = 31) hospitalized for different reasons served as controls. All strains were confirmed as ST 239 by S. aureus and mecA-specific PCR, spa, and multi-locus sequence typing (MLST). In each bacteremia patient, a unique pattern of S. aureus antigen-specific immune responses after infection was observed. Antibody levels among bacteremia patients were significantly higher than controls for HlgB (P = 0.001), LukD (P = 0.009), LukF (P = 0.0001), SEA (P = 0.0001), SEB (P = 0.011), SEC (P = 0.010), SEQ (P = 0.049), IsaA (P = 0.043), IsdA (P = 0.038), IsdH (P = 0.01), SdrD (P = 0.001), SdrE (P = 0.046), EsxA (P = 0.0001), and SA0104 (P = 0.0001). On the other hand, the antibody levels were significantly higher among controls for SSL3 (P = 0.009), SSL9 (P = 0.002), and SSL10 (P = 0.007) when the IgG level on the day of infection was compared with that measured on the day of admission. Diversity was observed in the immune response against the antigens. However, a set of antigens (IsaA, IsdA, IsdH, SdrD, and HlgB) triggered a similar type of immune response in different individuals. We suggest that these antigens could be considered when developing a multi-component (passive) vaccine. SEA and/or its specific antibodies seem to play a critical role during ST239 MRSA bacteremia and SEA-targeted therapy may be a strategy to be considered.

Molecular typing and antibiotic resistance patterns of methicillin-resistant Staphylococcus aureus isolates from clinical samples in Malaysia: An update.

A total of 120 non-consecutive MRSA isolates were obtained from hospitalized patients at Hospital Kuala Lumpur, Malaysia. All isolates were subjected to antimicrobial susceptibility tests and genotyping based on staphylococcal cassette chromosome mec(SCCmec), Staphylococcus aureus protein A typing (spa) and multilocus sequence typing (MLST). Vast majority of MRSA isolates were resistant to more than three classes of antibiotics. Five antibiotic resistance profiles were observed among the MRSA isolates. All isolates tested were still susceptible to vancomycin. Genotyping revealed isolates are highly clonal, where all MRSA belonged to the predominant Asian clone ST239 comprising 4 spa types. Spa typing revealed four different spa types. Continuous monitoring and effective therapeutic options for Asian MRSA clone is recommended.

Differences in humoral immune response between patients with or without nasal carriage of Staphylococcus aureus.

The humoral immune response against 43 staphylococcal antigens was compared among hospitalized patients where none of them had any staphylococcal infection on the day of admission with or without nasal Staphylococcus aureus carriage. Fifty-nine carriers and 59 matched non-carriers were studied. The carriers harbored S. aureus of 35 different spa types, including three t037/ST239 methicillin-resistant S. aureus (MRSA) (5.1%). Among the 118 patients, 31 acquired S. aureus during hospitalization. In colonized and non-colonized patients, unique patterns of S. aureus-specific immune responses were observed. The mean fluorescence indices (MFIs) of antibodies against 36/43 (83.7%) antigens were seen to be elevated among carriers. The MFI among carriers with acquisition was significantly higher for staphylococcal superantigen-like protein 5 (SSL5, p = 0.028) when compared to carriers without acquisition. High antibody levels against staphylococcal enterotoxin A (SEA) among carriers illustrate its role as a superantigen in both infection and colonization. We also report a dynamic immune response in S. aureus-carrying patients against the recently reported formyl peptide receptor-like inhibitory (FLIPr)-like protein. In the current study, the dynamics of antibodies against staphylococcal antigens among carrier patients seem quite similar to non-carrier patients. To better understand the dynamic immunogenicity during S. aureus infection and colonization, artificial colonization studies and investigation of the changes in the levels of antibodies against other staphylococcal antigens are recommended.

Nasal carriers are more likely to acquire exogenous Staphylococcus aureus strains than non-carriers.

We performed a prospective observational study in a clinical setting to test the hypothesis that prior colonization by a Staphylococcus aureus strain would protect, by colonization interference or other processes, against de novo colonization and, hence, possible endo-infections by newly acquired S. aureus strains. Three hundred and six patients hospitalized for >7 days were enrolled. For every patient, four nasal swabs (days 1, 3, 5, and 7) were taken, and patients were identified as carriers when a positive nasal culture for S. aureus was obtained on day 1 of hospitalization. For all patients who acquired methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus via colonization and/or infection during hospitalization, strains were collected. We note that our study may suffer from false-negative cultures, local problems with infection control and hospital hygiene, or staphylococcal carriage at alternative anatomical sites. Among all patients, 22% were prior carriers of S. aureus, including 1.9% whom carried MRSA upon admission. The overall nasal staphylococcal carriage rate among dermatology patients was significantly higher than that among neurosurgery patients (n = 25 (55.5%) vs. n = 42 (16.1%), p 0.005). This conclusion held when the carriage definition included individuals who were nasal culture positive on day 1 and day 3 of hospitalization (p 0.0001). All MRSA carriers were dermatology patients. There was significantly less S. aureus acquisition among non-carriers than among carriers during hospitalization (p 0.005). The mean number of days spent in the hospital before experiencing MRSA acquisition in nasal carriers was 5.1, which was significantly lower than the score among non-carriers (22 days, p 0.012). In conclusion, we found that nasal carriage of S. aureus predisposes to rather than protects against staphylococcal acquisition in the nose, thereby refuting our null hypothesis.

Antimicrobial susceptibility profiles, serotype distribution and virulence determinants among invasive, non-invasive and colonizing Streptococcus agalactiae (group B streptococcus) from Malaysian patients.

A total of 103 group B streptococci (GBS) including 22 invasive, 21 non-invasive, and 60 colonizing isolates were collected in a Malaysian hospital (June 2010-October 2011). Isolates were characterized by conventional and molecular serotyping and analyzed for scpB, lmb, hylB, cylE, bac, bca and rib gene content. Antimicrobial susceptibility to penicillins, macrolides, lincosamides, quinolones and tetracyclines was determined using disk diffusion and the MICs for penicillin were determined by E-test. Molecular serotyping for all eight serotypes (Ia, Ib, II-VII) was in full accordance with conventional serotyping. Overall, taking CS and MS together, serotype VI was the most common capsular type (22.3 %) followed by VII (21.4 %), III (20.4 %), Ia (17.5 %), V (9.7 %), II (7.7 %) and IV (1 %). Susceptibility to beta-lactam antimicrobials was prevalent (100 %). Resistance rates for erythromycin, clindamycin and tetracycline were 23.3 %, 17.5 % and 71.8 %, respectively. PCR-virulence gene screening showed the presence of cylE, lmb, scpB and hylB in almost all the isolates while rib, bca, and bac genes were found in 29.1 %, 14.6 % and 9.7 % of the isolates. Certain genes were significantly associated with specific serotypes, namely, rib with serotypes Ia, II, III and VI; bca and bac with serotypes II and III. Furthermore, serotype Ia was significantly more common among patients with invasive infections (p < 0.01) and serotype VI isolates were significantly more common among carriers (p < 0.05). In summary, serotype distribution correlates with virulence gene content will be useful in epidemiological studies and design of vaccines.

Group B streptococcal bacteremia in a major teaching hospital in Malaysia: a case series of eighteen patients.

BACKGROUND: Group B Streptococcus (GBS) is a leading cause of infections such as meningitis and septicemia in neonates and pregnant women; however the significance of invasive GBS disease has not been clearly defined in non-pregnant adults. METHODS: We reviewed the hospital records of 18 cases with GBS bacteremia who attended the Universiti Kebangsaan Malaysia Medical Centre from June 2010 to October 2011. We analyzed the clinical findings of both bacteremic adults and neonates and compared them to previous studies of GBS bacteremia. Serotyping was done by latex agglutination test using 10 distinct antisera (Ia, Ib, and II-IX). RESULTS: During the period of 1 year and 4 months, there were 18 patients with GBS bacteremia. Five cases occurred in neonates, one in a parturient woman, and 12 in other adults. All neonates with bacteremia were males and two of them were premature. Septicemia was the most common clinical presentation in neonates. They were treated with intravenous (IV) penicillin G and gentamicin. The adults included nine men (69%) and four women (31%). Their mean age was 60 years and all patients had more than two underlying conditions. The most common clinical syndrome was pneumonia (n=6, 46.5%). The others were peritonitis (n=3, 23.1%), primary bacteremia (n=2, 15.5%), septic arthritis (n=2, 15.5%), skin and soft tissue infection (n=1, 7.7%), meningitis (n=1, 8%), urinary tract infection (n=1, 8%), and intravascular device infection (n=1, 7.7%). Cardiovascular diseases (n=7, 53.8%) were the most common underlying conditions, and diabetes mellitus (n=5, 38.5%) was second. The other co-morbid conditions were hyperlipidemia (n=3, 23.1%), renal disease (n=3, 23.1%), liver disease and/or alcohol abuse (n=3, 23.1%), autoimmune disease or immunosuppressive condition (n=2, 15.5%), malignancy (n=2, 15.5%), respiratory disease (n=1, 8%), and postpartum condition (n=1, 8%), as well as miscellaneous conditions including intravenous drug abuse, HIV infection, and trauma (n=2, 15.5%). Polymicrobial bacteremia was found in five (45.4%) cases and Staphylococcus aureus was the most common concurrent bacterial isolate. Of the 18 GBS isolates in both adults and neonates, serotype Ia was predominant (38.9%), followed by VI (27.8%), V (11.1%), and III (5.5%); the remaining 16.7% were non-typeable. CONCLUSIONS: GBS bacteremia is a significant problem and is associated with serious underlying disease, which may result in a high rate of mortality, not only in neonates and pregnant women, but also in non-pregnant adults.

Genetic variation among methicillin-resistant Staphylococcus aureus isolates from cancer patients in Saudi Arabia.

One hundred and twenty methicillin-resistant Staphylococcus aureus (MRSA) isolated from cancer and non-cancer patients in Saudi Arabia were investigated for antibiotic resistance, virulence determinants and genotypes. The majority of MRSA isolates from cancer (n = 44, 73.3 %) and non-cancer patients (n = 34, 56.7 %) were multi-resistant to more than four classes of antibiotics. Virulence gene profiling showed that all strains were commonly positive for adhesin genes, except ebps and bbp genes, which were not detected in any isolate. Although the presence of adhesin genes varied slightly among MRSA isolates from cancer and non-cancer patients, these variations were not found to be statistically significant. In contrast, the presence of the toxin genes seb, sec, seg and sei was significantly elevated in MRSA strains isolated from cancer patients. Multilocus sequence typing (MLST) detected six and nine sequence types (STs) among isolates from cancer and non-cancer patients, respectively. Using spa typing, 12 and 25 types were detected, including four new types. The ability of different MRSA clones to become multi-resistant and their ability to acquire different virulence factors may contribute to their success as pathogens in individual groups of patients.

Rapid detection and identification of pathogens in patients with continuous ambulatory peritoneal dialysis (CAPD) associated peritonitis by 16s rRNA gene sequencing.

Peritonitis still remains a serious complication with high rate of morbidity and mortality in patients on CAPD. Rapid and accurate identification of pathogens causing peritonitis in a CAPD patient is essential for early and optimal treatment. The aim of this study was to use 16S rRNA and ITS gene sequencing to identify common bacterial and fungal pathogens directly from the peritoneal fluid without culturing. Ninety one peritoneal fluids obtained from 91 different patients on CAPD suspected for peritonitis were investigated for etiological agents by 16S rRNA and ITS gene sequencing. Data obtained by molecular method was compared with the results obtained by culture method. Among the 45 patients confirmed for peritonitis based on international society of peritoneal dialysis (ISPD) guidelines, the etiological agents were identified in 37(82.2%) samples by culture method, while molecular method identified the etiological agents in 40(88.9%) samples. Despite the high potential application of the 16S rRNA and ITS gene sequencing in comparison to culture method to detect the vast majority of etiological agents directly from peritoneal fluids; it could not be used as a standalone test as it lacks sensitivity to identify some bacterial species due to high genetic similarity in some cases and inadequate database in Gene Bank. However, it could be used as a supplementary test to the culture method especially in the diagnosis of culture negative peritonitis.

Methicillin sensitive Staphylococcus aureus (MSSA) isolates as a potential source for the emergence of USA 300 methicillin resistant Staphylococcus aureus (MRSA) in Malaysia.

We investigated the potential of USA300 MRSA emergence in Malaysia by examining 268 MSSA isolates from both community (110) and healthcare (158) settings. Nine isolates from both the environments were similar to the USA300 MRSA background based on MLST, spa and PFGE type. These results underscore the importance of continued surveillance to monitor the emergence of USA300 MRSA in Malaysia.

Diversity in the antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus clones.

Methicillin-resistant Staphylococcus aureus (MRSA) is well known for its epidemicity, with the emergence of new clones on a daily basis. Diversity in the clonal types of MRSA challenges the success of treatment, as different clones respond to different sets of antibiotics. However, the antibiotic susceptibility among the isolates within the same clones is largely unexplored. In a previous study on MRSA epidemiology in Malaysia, we identified six major clonal complexes (ST-239-CC8, ST-1-CC1, ST-188-CC1, ST-22-CC22, ST-7-CC7 and ST-1283-CC8). In the present study, we investigated the antibiotic susceptibility patterns of isolates of different clones. Three hundred and eighty-nine MRSA isolates were subjected to the disc diffusion test, oxacillin minimum inhibitory concentration (MIC) determination and assessment of the distribution of macrolide, lincosamide and streptogramin B (MLS(B)) resistance genes. Thirty-six different antibiotic profiles were observed: 30 (83.3 %) among ST-239, 2 (5.6 %) among ST-1283 and 1 (2.8 %) each for ST-1, ST-7, ST-22 and ST-188. All ST-239 (362, 9 %) isolates were multiple drug-resistant (MDR; resistant to more than three classes of antibiotics) and had oxacillin MICs >256 mg/l. Among the 385 clindamycin-resistant isolates, 375 (96.4 %) illustrated inducible resistance (D-zone-positive), while 10 (2.6 %) showed constitutive resistance. The vast majority of the macrolide-resistant isolates carried the ermA gene (95.1 %), followed by ermC (12.9 %). Diversity in the antibiotic susceptibilities of isolates within the clones emphasises the need for continuous surveillance of MDR strains to prescribe the correct antibiotic rather than empirical treatment. This will likely reduce the emergence of new endemic or epidemic resistant MRSA clones.

Effect of tannin extract against Pseudomonas aeruginosa producing metallo beta-lactamase.

Carbapenems are the most potent beta-lactam agents with a broad-spectrum activity against Gram-negative and Gram-positive bacteria. They are stable in the presence of penicillinases and cephalosporinases. This study was focused on frequency of metallo beta- lactamase (MBL) among Pesudomonas aeruginosa strains isolated in patients with urinary tract infection, effect of tannin against PA positive strains which produced blaVIM or blaIMP and both of these genes (Species). Detection of MBL was performed by phonotypic and genotypic methods. Tannin extract was tested against P. aeruginosa producing MBL. During the study period, 240 P. aeruginosa isolates were identified. Among them 64 (26.6 percent) isolates were imipenem non-susceptible and confirmed by imipenem/EDTA. Our results revealed that the growth of blaVIM positive P. aeruginosa inhibited at 15 microg/ml concentration. The experiment repeated for blaIMP-positive P. aeruginosa and P. aeruginosa which harbored blaIMP and blaVIM, the results showed 35 microg/ml was the best concentration for inhibition of P. aeruginosa-positive blaIMP and also P. aeruginosa blaIMP and blaVIM. In conclusion, tannin was effective against P. aeruginosa producing blaVIM and blaIMP and both of them so it can be substituted with common antibiotics. The result showed significantly P. aeruginosa-harbored blaIMP was more responsible for imipenem resistance than P. aeruginosa-positive blaVIM. Interestingly, tannin was more effective against MBL-P. aeruginosa in comparison with current antibiotics.

High prevalence of qacA/B carriage among clinical isolates of meticillin-resistant Staphylococcus aureus in Malaysia.

The minimum inhibitory concentrations (MICs) of 60 meticillin-resistant Staphylococcus aureus (MRSA) isolates from Malaysia to three antiseptic agents - benzalkonium chloride (BZT), benzethonium chloride (BAC) and chlorhexidine digluconate (CHG) - were determined. All isolates had MICs ranging from 0.5 to 2 mg/L. Antiseptic resistance genes qacA/B and smr were detected in 83.3% and 1.6% of the isolates, respectively. Carriage of qacA/B correlated with reduced susceptibility to CHG and BAC. This is the first report of the prevalence of qacA/B and smr gene carriage in Malaysian MRSA isolates, with a high frequency of qacA/B carriage. The presence of these antiseptic resistance genes and associated reduced susceptibility to antiseptic agents may have clinical implications.