USA300 methicillin-resistant S. aureus (USA300 MRSA) colonization and the risk of MRSA infection in residents of extended-care facilities.

To examine the pathogenesis of USA300 MRSA infection in long-term care residents, we performed a retrospective cohort study of 1691 adult residents of two extended-care facilities from 2003 to 2007 to assess whether the risk of subsequent MRSA infection is higher in USA300 MRSA-colonized residents compared to non-colonized residents or non-USA300 MRSA colonized residents. Six per cent of residents were colonized with USA300 MRSA; 12% of residents were colonized with non-USA300 MRSA; and 101 residents developed MRSA infection. The risk of infection was twofold higher in residents colonized with USA300 MRSA compared to residents not colonized with MRSA [adjusted hazard ratio 2·3, 95% confidence interval (CI) 1·1-4·5]. The risk of infection in USA300 MRSA-colonized residents was similar to USA300 MRSA non-colonized residents (relative risk 1·1, 95% CI 0·5-2·3). Our findings show that colonization with USA300 MRSA increases the risk of MRSA infection suggesting a similar pathogenesis.

Susceptibility patterns and serotypes of non-typhoidal salmonella in Trinidad.

OBJECTIVE: To study the serotype distribution of non-typhoidal salmonella isolated from clinical specimens and to evaluate their susceptibility patterns to the most commonly prescribed antimicrobial agents used in this region. METHODS: A retrospective study during the period 1993 1999 was carried out at the Eric Williams Medical Sciences Complex Microbiology Laboratory, a teaching hospital in the northwestern part of Trinidad. Strains of non-typhoidal salmonella were serogrouped with polyvalent Salmonella O antiserum and sent to the local Public Health Laboratory for confirmation and further serotyping. RESULTS: A total of 412 strains of non-typhoidal salmonella were serotyped. Of the 13 serotypes, Salmonella enteritidis was the most prevalent 57%, followed by Salmonella typhimurium, 25%, Salmonella virchow 5% and Salmonella heidelberg, 4%. Three hundred and sixty-two (87.5%) non-typhoidal salmonella were isolated from stool, 38 (9%) from blood, 8 (2%) from urine and 4 about 1% from infected wounds. Of the 13 serotypes only Salmonella enteritidis, Salmonella typhimurium, Salmonella virchow and Salmonella heidelberg were simultaneously isolated from blood and stool. One serotype, Salmonella aberdeen, was encountered for the first time in 1993. All isolates were fully sensitive to chloramphenicol, gentamicin, cefuroxime and ceftrioxone. Resistance to ampicillin, augmentin and co-trimoxazole was less than 4%. One third of all non-typhoidal salmonella isolates were resistant to tetracyclines. CONCLUSION: The most prevalent serotypes were Salmonella enteritidis and Salmonella typhimurium which accounted for 82% of all isolates. The prevalence of resistance of non-typhoidal salmonella to antibiotics was very low (5%). Therefore, due to this low prevalence of resistance, we did not provide details of resistance in relation to serotype. However, it was observed that of the 137 non-typhoidal salmonella resistant to tetracycline, more than 80% were Salmonella enteritidis and Salmonella typhimurium strains. Of the 9 antibiotics, tetracycline was the only drug to which one-third of the non-typhoidal salmonella were resistant. Due to the risk of resistance continued surveillance of susceptibility patterns of non-typhoidal salmonella to antibiotics must be maintained and encouraged.

Bacteriuria in the elderly population in a developing country.

Among 1470 elderly hospitalized and nonhospitalized people, 566 cases of bacteriuria were identified. There were 663 men (41.5% with bacteriuria) and 807 women (36.0% with bacteriuria). The overall prevalence of bacteriuria was 38.5%. More than 90% of the isolates were gram-negative organisms with Proteus species being the predominant pathogen among men, with 68.1% seen among inpatients. Escherichia coli was the main pathogen in women, with 62.0% recovered from inpatients. Catheterization was seen most commonly among non-hospitalized males with outflow obstruction. Catheter care in this population is often performed at home by these men who either refuse prostate surgery, are not fit for surgery, or are awaiting surgery. Polymicrobic bacteriuria was identified more frequently (approximately 60%) among the catheterized group. Of the 440 gram-negative bacilli recovered as single organisms, 352 (80.0%) were resistant to ampicillin, cephalothin, and tetracycline, whereas 229 (52.0%) were resistant to co-trimoxazole. The most effective antibiotics (in increasing order of sensitivity; 80% - 100%) were augmentin, nalidixic acid, cefuroxime, gentomicin, and ciprofloxacin. No mortality due to bacteremia complicated by bacteriuria was observed during the study period.

Bacteriuria in the elderly population in a developing country

Among 1470 elderly hospitalized and nonhospitalized people, 566 cases of bacteriuria were identified. There were 663 men (41.5% with bacteriuria) and 807 women (36.0% with bacteriuria). The overall prevalence of bacteriuria was 38.5%. More than 90% of the isolates were gram-negative organisms with Proteus species being the predominant pathogen among men, with 68.1% seen among inpatients. Escherichia coli was the main pathogen in women, with 62.0% recovered from inpatients. Catheterization was seen most commonly among non-hospitalized males with outflow obstruction. Catheter care in this population is often performed at home by these men who either refuse prostate surgery, are not fit for surgery, or are awaiting surgery. Polymicrobic bacteriuria was identified more frequently (approximately 60%) among the catheterized group. Of the 440 gram-negative bacilli recovered as single organisms, 352 (80.0%) were resistant to ampicillin, cephalothin, and tetracycline, whereas 229 (52.0%) were resistant to co-trimoxazole. The most effective antibiotics (in increasing order of sensitivity; 80% - 100%) were augmentin, nalidixic acid, cefuroxime, gentomicin, and ciprofloxacin. No mortality due to bacteremia complicated by bacteriuria was observed during the study period.

Prevalence of resistance to antimicrobials of Escherichia coli isolates from clinical sources at a private hospital in Trinidad.

Antimicrobial susceptibility patterns of strains of Escherichia coli isolated between 1994 and 1998 were studied. Of the 1,283 strains examined, 75% were recovered from urine, 8.7% from wounds, 3.2% from blood, 2.6% from pus, and 10.5% from other sources. Isolates from inpatients and outpatients accounted for 46.1% and 53.9%, respectively. Gentamicin and nalidixic acid showed the greatest efficacy against isolates from both inpatients and outpatients, revealing a >90% sensitivity. Drugs with the lowest efficacies were ampicillin and amoxicillin-clavulanic acid, which showed a >45% resistance. Tetracycline showed a significant decline in resistance from 1994 to 1998 among strains from both inpatients and outpatients (P < 0.001). This decline may be related to a policy of restrictive antibiotic reporting by the Microbiology Laboratory and seminars for general practitioners, subsequent to an island-wide survey an antibiotic resistance. A similar pattern of declining resistance was also observed for cefuroxime. E. coli sensitivity to co-trimoxazole was relatively stable during the study period. Although the overall prevalence of resistance among E. coli strains is relatively low, on-going surveillance of bacterial resistance must continue. The microbial antibiogram can provide general practitioners and clinicians with data essential for optimum empiric choices. Further, the introduction of a policy of restrictive reporting may act "synergistically" with the education of doctors on resistance patterns, to effect island-wide reduction of antimicrobial resistance.

Neonatal sepsis and mortality in a regional hospital in Trinidad: aetiology and risk factors.

A total of 132 neonatal deaths among 627 infants admitted to the neonatal ward of the San Fernando General Hospital, Trinidad over a 2-year period were reviewed. The most common cause of death was prematurity (43.9%). Infection was the second most common cause (21.2%). Pseudomonas aeruginosa and Staphylococcus aureus were the most frequently isolated organisms (43%). The major drugs used empirically in suspected cases of sepsis were ampicillin or ceftazidime plus gentamicin. About 85% of S. aureus were resistant to ampicillin, and P. aeruginosa resistance to ceftazidime and gentamicin was 76.7% and 72.1%, respectively. Significant risk factors in maternal history were infrequent antenatal care and prolonged rupture of membranes. The incidence of infection among low birthweight infants was 85.6%. Early-onset sepsis (86.4%) seemed to have a nosocomial origin because of the type of pathogens seen. There is an urgent need to improve the staff-to-patient ratio in the neonatal unit and for staff to be constantly reminded to employ simple infection control practices such as proper hand-washing to reduce cross-infections.

Prevalence of resistance to antimicrobials of Escherichia coli isolates from clinical sources at a private hospital in Trinidad

Antimicrobial susceptibility patterns of strains of Escherichia coli isolated between 1994 and 1998 were studied. Of the 1,283 strains examined, 75% were recovered from urine, 8.7% from wounds, 3.2% from blood, 2.6% from pus, and 10.5% from other sources. Isolates from inpatients and outpatients accounted for 46.1% and 53.9%, respectively. Gentamicin and nalidixic acid showed the greatest efficacy against isolates from both inpatients and outpatients, revealing a >90% sensitivity. Drugs with the lowest efficacies were ampicillin and amoxicillin-clavulanic acid, which showed a >45% resistance. Tetracycline showed a significant decline in resistance from 1994 to 1998 among strains from both inpatients and outpatients (P < 0.001). This decline may be related to a policy of restrictive antibiotic reporting by the Microbiology Laboratory and seminars for general practitioners, subsequent to an island-wide survey an antibiotic resistance. A similar pattern of declining resistance was also observed for cefuroxime. E. coli sensitivity to co-trimoxazole was relatively stable during the study period. Although the overall prevalence of resistance among E. coli strains is relatively low, on-going surveillance of bacterial resistance must continue. The microbial antibiogram can provide general practitioners and clinicians with data essential for optimum empiric choices. Further, the introduction of a policy of restrictive reporting may act "synergistically" with the education of doctors on resistance patterns, to effect island-wide reduction of antimicrobial resistance.

Knowledge and awareness of tuberculosis among pre-university students in Trinidad.

The purpose of the study was to determine the level of knowledge and attitudes among pre-university students in Trinidad and Tobago on the pre-disposing factors and prevention of tuberculosis and the management of persons with the disease. More than 90% (542 of 600) of participating students from nine secondary schools duly completed the self-administered questionnaires. Two-thirds of the students were girls (336) and the rest were boys (206). The ages of the participants ranged from 16-19 years and more than 82% of them belonged to the 17-18 year old age group. The least represented was the 19 year olds. The study showed that although 92.8% had heard of tuberculosis, overall knowledge about the disease was generally poor. The majority of students (77.5%) believed the disease could be prevented, but 10.3% knew of the BCG vaccine and only 11.1% knew about the Mantoux skin test. The study also demonstrated the need for renewed efforts in health education for the public, clarifying areas of misunderstandings about important and common diseases like tuberculosis, in developing countries.

Prevalence of bacterial pathogens and susceptibility patterns from clinical sources in Trinidad.

During a 12-month period (January-December, 1997), bacterial isolates of specimens from in-patients and out-patients of the Eric Williams Medical Sciences Complex (EWMSC) were reviewed. A total of 3,513 specimens were processed, 43.1% from in-patients and 56.9% from out-patients. Of the 3,513 specimens, 1129 (32.1%) yielded positive cultures. Micro-organisms from wounds, sputum and genital tract accounted for 90.2%, 51.5% and 31.8%, respectively, of all isolates. E coli (17.4%) and Enterococci (12.2%) were the predominant isolates and were also the major pathogens from blood stream infections, 25.8% and 18.2%, respectively, followed by P aeruginosa, 15.2%. High levels of resistance were seen to ampicillin, augmentin (amoxicillin-clavulanic acid) and tetracycline. The most effective antibiotics were ceftazidime (no resistance in E coli Citrobacter spp, non-typhoidal Salmonella and Group B streptococci, 63.2% resistance in Acinetobacter spp, 15.2% in Enterobacter spp, 17.4% in Klebsiella spp.], gentamicin [no resistance in Enterobacter and Citrobacter spp, and 89.5% in Acinetobacter spp), erythromycin (no resistance in Groups A and B streptococci, 85.1% in S aureus and S pneumoniae). The spectrum of isolates will provide clinicians with data on which to base their "best guess" aetiologic agent and choice of antibiotics when faced with infectious diseases in areas where laboratory assistance is not readily available.

Prevalence of Bacterial Pathogens and Susceptibility Patterns from clinical sources in Trinidad

During a 12-month period (January-December, 1997), bacterial isolates of specimens from in-patients and out-patients of the Eric Wiliams Sciences Complex (EWMSC) were reviewed. A total of 3,513 specimens were processed, 43.1 percent from in-patients and 56.9 percent from out-patients. Of the 3,513 specimens, 1,129 (32.1 percent) yielded positive cultures. Micro-organisms from wounds, sputum and genital tract accounted for 90.2 percent, 51.5 percent and 31.8 percent, respectively, of all isolates. E coli (17.4 percent) and Enterococci (12.2percent) were the predominant isolates and were also the major pathogens from blood stream infections, 25.8 percent and 18.2 percent, respectively, followed by P aeruginosa, 15.2 percent. High levels of resistance were seen to ampicillin, augmentin (amoxicillin-clavulanic acid) and tetracycline. The most effective antibiotics were ceftazidime (no resistance in E coli Citrobacter spp, non-typhoidal Salmonella and Group B streptococci, 63.2 percent resistance in Acinetobacter spp, 15.2 percent in Enterobacter spp, 17.4 percent in Klebsiella spp.], erythromycin (no resistance in Enterobacter and Citrobacter spp, and 89.5 percent in Acinetobacter (spp), erythromycin (no resistance in Groups A and B streptococci, 85.1 percent in S aurens and S pneumoniae). The spectrum of isolates will provide clinicians with data on which to base their "best guess" aetiologic agent and choice of antibiotics when faced with infectious diseases in areas where laboratory assistance is not readily available.(Au)

Prevalence of Bacterial Pathogens and Susceptibility Patterns from clinical sources in Trinidad

During a 12-month period (January-December, 1997), bacterial isolates of specimens from in-patients and out-patients of the Eric Wiliams Sciences Complex (EWMSC) were reviewed. A total of 3,513 specimens were processed, 43.1 percent from in-patients and 56.9 percent from out-patients. Of the 3,513 specimens, 1,129 (32.1 percent) yielded positive cultures. Micro-organisms from wounds, sputum and genital tract accounted for 90.2 percent, 51.5 percent and 31.8 percent, respectively, of all isolates. E coli (17.4 percent) and Enterococci (12.2percent) were the predominant isolates and were also the major pathogens from blood stream infections, 25.8 percent and 18.2 percent, respectively, followed by P aeruginosa, 15.2 percent. High levels of resistance were seen to ampicillin, augmentin (amoxicillin-clavulanic acid) and tetracycline. The most effective antibiotics were ceftazidime (no resistance in E coli Citrobacter spp, non-typhoidal Salmonella and Group B streptococci, 63.2 percent resistance in Acinetobacter spp, 15.2 percent in Enterobacter spp, 17.4 percent in Klebsiella spp.], erythromycin (no resistance in Enterobacter and Citrobacter spp, and 89.5 percent in Acinetobacter (spp), erythromycin (no resistance in Groups A and B streptococci, 85.1 percent in S aurens and S pneumoniae). The spectrum of isolates will provide clinicians with data on which to base their "best guess" aetiologic agent and choice of antibiotics when faced with infectious diseases in areas where laboratory assistance is not readily available.

The changing patterns of antimicrobial susceptibility of urinary pathogens in Trinidad.

OBJECTIVE: The prevalence of antimicrobial resistance in urinary pathogens is increasing worldwide. Accurate bacteriologic records of culture results may provide guidance on empirical therapy before sensitivity patterns are available. We report the changing antibiograms of pathogens associated with urinary tract infections (UTI) over a 4-year period at a newly commissioned hospital complex diagnostic laboratory in Trinidad. METHODS: From January 1992 to December 1995, kept records of antibiograms of all urinary pathogens isolated were examined. Samples were derived from hospital sources (wards and out-patient clinics) and general practice sources (health centers and general practitioners). Quantitative bacteriologic cultures were performed according to standard laboratory procedures, and identification of isolates were based on Gram reaction, morphology and biochemical characteristics. Significant bacteriuria was defined as the presence of greater than 100,000 organisms per mL of a midstream urine specimen or more than 3000 bacteria per mL in a catheter specimen of a single specie. Antimicrobial sensitivities were done using the following antibiotics: norfloxacin, ampicillin, tetracycline, nitrofurantoin, gentamicin, co-trimoxazole (sulfamethoxazole-trimethoprim), trimethoprim, nalidixic acid, cephalexin and augmentin (amoxicillin-clavulanic acid). Control organism was E coli NCTC 10,418 strain. RESULTS: The total number of specimens for the 4-year period in hospital was 14,181 with an isolation rate of 17%, and a general practice isolation rate of 67% from a total of 5,088 specimens. E coli was the most frequent isolate in both hospital (40%) and general practice (30%). There was an increase isolation of P aeruginosa from community practice reflecting an increase in home care catheterised male patients. Resistance to tetracycline was most significant in hospital (99%) and general practice (81%). Similar trend was observed for trimethoprim in hospital, and co-trimoxazole in both practices. Resistance to ampicillin, augmentin and cephalexin was relatively stable over the 4-year period. CONCLUSION: We conclude that laboratories should encourage accurate bacteriologic record keeping of urinary isolates and their antibiograms to serve as guidance in empirical treatment in UTI. Also, urine microscopy may reduce the number of specimens sent for culture which are not cost-effective.

Significance of coagulase-negative staphylococci in urinary tract infections in a developing country.

The biotyping of 154 (3.8%) coagulase-negative staphylococci from 4,051 urinary specimens in males and females was performed. Their significance and antimicrobial susceptibility patterns were also evaluated. S. saprophyticus and S. epidermidis accounted for approximately 90% of isolates from females, while in males only 68.7% of isolates were S. epidermidis, S. hominis, S. xylosus, S. simulans, and S. hyicus, The mean age for females with infections due to S. saprophyticus was 23 years while for males with infections due to S. epidermidis it was 77 years. The mean age for infections due to other staphylococci was higher in males than in females. There was little variation in the antimicrobial susceptibility pattern in the various species. The results suggest that apart from S. saprophyticus and S. epidermidis, six other species of coagulase-negative staphylococci (S. hominis, S. xylosus, S. simulans, S. hyicus, S. hemolyticus, and S. cohnii) account for most urinary tract infections irrespective of gender.

The changing patterns of antimicrobial susceptibility of urinary pathogens in Trinidad

OBJECTIVE: The prevalence of antimicrobial resistance in urinary pathogens is increasing worldwide. Accurate bacteriologic records of culture results may provide guidance on empirical therapy before sensitivity patterns are available. We report the changing antibiograms of pathogens associate with urinary tract infections (UTI) over a 4-year period at a newly commissioned hospital complex diagnostic laboratory in Trinidad. METHODS: From January 1992 to December 1995, kept records of antibiograms of all urinary pathogens isolated were examined. Samples were derived from hospital sources (wards and out-patient clinics) and general practice sources (health centers and general practitioners). Quantitative bacteriologic cultures were performed according to standard laboratory procedures, identification of isolates were based on Gram reaction, morphology and biochemical characteristics. Significant bacteriuria was defined as the presence of greater than 100,000 organisms per mL of a midstream urine specimen or more than 3000 bacteria per mL in a catheter specimen of a single specie. Antimicrobial sensitivities were done using the following antibiotics: norfloxacin, ampicillin, tetracycline, nitrofurantoin, gentamicin, co-trimoxazole (sulfamethoxazole-trimethoprim), trimethoprim, nalidixic acid, cephalexin and augmentin (amoxicillin-clavulanic acid). Control organism was E coli NCTC 10,418 strain. RESULTS: The total number of specimens for the 4-year period in hospital was 14,181 with an isolation rate of 17 percent, and a general practice isolation rate of 67 percent from a total of 5,088 specimens. E coli was the most frequent isolate in both hospital (40 percent) and general practice (30 percent). There was an increase isolation of P aeruginosa from community practice reflecting an increase in home care catheterised male patients. Resistance to tetracycline was most significant in hospital (99 percent) and general practice (81 percent). Similar trend was observed for trimethorpim in hospital, and co-trimoxazole in both practices. Resistance to ampicillin, augmentin and cephalexin was relatively stable over the 4-year period. CONCLUSION: We conclude that laboratories should encourage accurate bacteriologic record keeping of urinary isolates and their antibiograms to serve as guidance to serve as guidance in empirical treatment in UTI. Also, urine microscopy may reduce the number of specimens sent for culture which are not cost-effective.(Au)

Significance of coagulase-negative staphylococci in urinary tract infections in a developing country

The biotyping of 154 (3.8 percent) coagulase-negative staphylococci from 4,051 urinary specimens in males and females was performed. Their significance and antimicrobial susceptibility patterns were also evaluated. S. saprophyticus and S. epidermidis accounted for approximately 90 percent of isolates from females, while in males only 68.7 percent of isolates were S. epidermidis, S. hominis, S. xylosus, S. simulans, and S. hyicus. The mean age for females with infection fue to S. saprophyticus was 23 years while for males with infections due to S. epidermidis it was 77 years. The mean age for infection due to other staphylococci was higher in males than females. There was little variation in the antimicrobial susceptibility pattern in the various species. The results suggest that apart from S. saprophyticus and S. epidermidis, six other species of coagulase-negative staphylococci (S. hominis, S. xylosus, S. simulans, S. hyicus, S. hemolyticus, and S. cohnii) account for most urinary tract infections irrespective of gender(AU)