Prevalence of Shigella serogroups and their antimicrobial resistance patterns in southern Trinidad.

The serogroup distribution and antimicrobial susceptibility patterns of Shigella isolates obtained from stool specimens of persons with acute diarrhoea in community-based studies from southern Trinidad during 1997-2006 were reviewed. Of the 5,187 stool specimens, 392 (8%) were positive for Shigella organisms. From these 392 isolates, 88.8% were recovered from children aged >0-10 year(s). Shigella sonnei was the most frequently-isolated serogroup (75%), followed by S. flexneri (19%), S. boydii (4.1%), and S. dysenteriae (1.8%). S. flexneri was the major isolate among the >20-30 years age-group. The most common drug resistance among all age-groups was to ampicillin. All strains of S. flexneri, S. boydii, and S. dysenteriae were fully susceptible to aztreonam, gentamicin, and ciprofloxacin. S. sonnei, the most common species isolated, showed resistance to all antibiotics tested. The data showed that, throughout the study period, the resistance to commonly-used drugs was relatively low. Since resistance to several drugs seems to be emerging, continuous monitoring of resistance patterns is mandatory for the appropriate selection of empiric antimicrobial drugs in the therapy of suspected cases of shigellosis.

The emergence of mupirocin resistance among clinical isolates of methicillin-resistant Staphylococcus aureus in Trinidad: a first report.

The objective of the study was to investigate the trend of mupirocin resistance among methicillin-resistant Staphylococcus aureus (MRSA) in Trinidad. No premarketing susceptibility surveillance was ever done following the introduction of mupirocin in 1986. A total of 188 MRSA strains recovered over a 2-year period from various body sites were tested for mupirocin resistance via the disc diffusion method. The major sources of MRSA were surgical site infections (74.0 per cent) and bloodstream infections (8.0 per cent). High-level and low-level mupirocin resistance were detected in 26.1 and 44.1 per cent of MRSA stains, respectively. Resistances to other non-beta-lactam antibiotics were also high. Ninety-eight percent of all MRSA were resistant to erythromycin. This was followed by resistance rates of 96.8, 95.2, 94.1, 93.6, and 93.1 per cent, for gentamicin, ciprofloxacin, amikacin and tobramycin, co-trimoxazole, and tetracycline, respectively. No MRSA strains were found to be resistant to vancomycin, linezolid, and quinupristin-dalfopristin. The study showed that mupirocin resistance among Trinidadian MRSA strains was relatively high compared to that seen in other countries. Because of the increasing prevalence of MRSA at the San Fernando General Hospital (SFGH) and the apparently increasing resistance to mupirocin, frequent monitoring of MRSA susceptibility patterns and infection control initiatives may be helpful in reducing the incidence of MRSA with a concomitant decrease in mupirocin resistance. This report is the first after 20 years of continuous use of the drug at the SFGH.

Prevalence of Shigella serogroups and their antimicrobial resistance patterns in southern Trinidad.

The serogroup distribution and antimicrobial susceptibility patterns of Shigella isolates obtained from stool specimens of persons with acute diarrhoea in community-based studies from southern Trinidad during 1997-2006 were reviewed. Of the 5,187 stool specimens, 392 (8 per cent) were positive for Shigella organisms. From these 392 isolates, 88.8 per cent were recovered from children aged >0-10 year(s). Shigella sonnei was the most frequently-isolated serogroup (75 per cent), followed by S. flexneri (19 per cent), S. boydii (4.1 per cent), and S. dysenteriae (1.8 per cent). S. flexneri was the major isolate among the >20-30 years age-group. The most common drug resistance among all age-groups was to ampicillin. All strains of S. flexneri, S. boydii, and S. dysenteriae were fully susceptible to aztreonam, gentamicin, and ciprofloxacin. S. sonnei, the most common species isolated, showed resistance to all antibiotics tested. The data showed that, throughout the study period, the resistance to commonly-used drugs was relatively low. Since resistance to several drugs seems to be emerging, continuous monitoring of resistance patterns is mandatory for the appropriate selection of empiric antimicrobial drugs in the therapy of suspected cases of shigellosis.

The emergence of mupirocin resistance among clinical isolates of methicillin-resistant Staphylococcus aureus in Trinidad: a first report.

The objective of the study was to investigate the trend of mupirocin resistance among methicillin-resistant Staphylococcus aureus (MRSA) in Trinidad. No premarketing susceptibility surveillance was ever done following the introduction of mupirocin in 1986. A total of 188 MRSA strains recovered over a 2-year period from various body sites were tested for mupirocin resistance via the disc diffusion method. The major sources of MRSA were surgical site infections (74.0%) and bloodstream infections (8.0%). High-level and low-level mupirocin resistance were detected in 26.1 and 44.1% of MRSA stains, respectively. Resistances to other non-beta-lactam antibiotics were also high. Ninety-eight percent of all MRSA were resistant to erythromycin. This was followed by resistance rates of 96.8, 95.2, 94.1, 93.6, and 93.1%, for gentamicin, ciprofloxacin, amikacin and tobramycin, co-trimoxazole, and tetracycline, respectively. No MRSA strains were found to be resistant to vancomycin, linezolid, and quinupristin-dalfopristin. The study showed that mupirocin resistance among Trinidadian MRSA strains was relatively high compared to that seen in other countries. Because of the increasing prevalence of MRSA at the San Fernando General Hospital (SFGH) and the apparently increasing resistance to mupirocin, frequent monitoring of MRSA susceptibility patterns and infection control initiatives may be helpful in reducing the incidence of MRSA with a concomitant decrease in mupirocin resistance. This report is the first after 20 years of continuous use of the drug at the SFGH.

Bacteremia in children at a regional hospital in Trinidad.

OBJECTIVE: The objective of this study was to provide a Trinidadian perspective on pediatric community-acquired and hospital-acquired bacteremia via the documentation of common etiologic agents, antimicrobial profiles of the isolated pathogens, and patient outcome. METHODS: This was a six-year retrospective study of children with bacteremia admitted to the pediatric wards of the San Fernando General Hospital, Trinidad. RESULTS: Seven hundred and four episodes of pediatric bacteremia were reviewed during the six-year study period. The predominant isolate was Staphylococcus aureus (23.9%), followed by Pseudomonas aeruginosa (15.5%), Klebsiella pneumoniae (12.5%), and Enterobacter spp (11.1%). The remaining isolates each accounted for less than 10% of total isolates. The mortality rate was highest for P. aeruginosa (39.4%), Streptococcus pneumoniae (22.5%), and Escherichia coli (19.2%). Of the six cases due to Neisseria meningitidis, only two survived. The overall mortality rate for the study period was 15.1%, but varied considerably according to age. All deaths due to P. aeruginosa and E. coli occurred in neonates. Almost 90% and about half of all S. aureus were resistant to ampicillin and erythromycin, respectively; nineteen (11.3%) were methicillin-resistant. More than 95% of K. pneumoniae and more than 87% of Haemophilus influenzae were resistant to ampicillin. Group B streptococci were fully susceptible to ampicillin and amoxicillin-clavulanic acid, but showed >90% and >70% resistance to tetracycline and trimethoprim-sulfamethoxazole, respectively. Of the 40 strains of S. pneumoniae isolated, 10.0% had a minimum inhibitory concentration (MIC) >or=4 microg/mL (resistance) and 12.5% had a MIC=2.0 microg/mL (intermediate resistance) to ceftriaxone, while 7.5% showed intermediate resistance (MIC between 0.12 and 1 microg/mL) and 25.0% showed resistance (MIC >or=2 microg/mL) to penicillin. CONCLUSION: The bacteremia rate was found to be 8.4% among hospitalized children suspected of having sepsis and from whom a blood culture was positive. Bacteremia was also associated with a high mortality rate of 15.1%. An unusually high level of bacteremia with Gram-negative enteric bacteria was seen, which might indicate cross infection and reflect a breakdown in infection control measures. Relatively high-level resistance of S. pneumoniae to penicillin and ceftriaxone was not seen, even though the overall prevalence of resistance to other antibiotics among other pathogens was relatively low. The drugs that showed the greatest efficacy were imipenem, gentamicin, ciprofloxacin, and the cephalosporins ceftazidime and ceftriaxone.

Methicillin-resistant Staphylococcus aureus prevalence: current susceptibility patterns in Trinidad.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most widespread causes of nosocomial infections worldwide. Recently, reports have emerged that S. aureus strains recovered from community-acquired infections are also methicillin-resistant. This study was undertaken to analyze the prevalence of methicillin resistance among isolates at a regional hospital in Trinidad, and document the current resistance profile of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) to the commonly used anti-staphylococcal agents. METHODS: Over a 6-year period we analyzed 2430 isolates of S. aureus strains recovered from various clinical sources, from hospital and community practices. Antimicrobial susceptibility testing was done according to guideline recommendations of the National Committee for Clinical Laboratory Standards. RESULTS: The prevalence of MRSA from surgical/burn wounds, urine and pus/abscess were 60.1%, 15.5% and 6.6%, respectively. The major sources of MSSA were surgical/burn wounds, pus/abscess and upper respiratory tract specimens with rates of 32.9%, 17.1% and 14.3%, respectively. The greatest prevalence of resistance of MRSA was seen for erythromycin (86.7%), and clindamycin (75.3%). Resistance rates among MSSA were highest for ampicillin (70%). Resistance rates for tetracycline were similar among both MRSA (78.7%) and MSSA (73.5%). The MRSA recovery rates from nosocomial sources (20.8%) was significantly higher than that of previous years (12.5%) (p < 0.001), whereas rates among community isolates were relatively similar for the same period (4.1% versus 8.1%). CONCLUSION: The prevalence of MRSA in the hospital increased from 12.5% in 1999 to 20.8% in 2004. Most isolates were associated with infected surgical/burn wounds which may have become infected via the hands of HCPs during dressing exercises. Infection control measures aimed at the proper hand hygiene procedures may interrupt the spread of MRSA. HCPs may also be carriers of MRSA in their anterior nares. Surveillance cultures of both patients and HCPs may help to identify carriers who would be offered antibiotics to eradicate the organisms. Most MRSA are resistant to several non-beta-lactam antibiotics. Frequent monitoring of susceptibility patterns of MRSA and the formulation of a definite antibiotic policy maybe helpful in decreasing the incidence of MRSA infection.

Clinical sources and prevalence of resistance to antimicrobials of Klebsiella pneumoniae strains in Trinidad.

OBJECTIVE: To assess the frequency of Klebsiella pneumoniae (K. pneumoniae) recovery from clinical specimens from hospital and community patients, their antibiotic profile, the extent of extended-spectrum beta lactamase (ESBL) production among such isolates, and the impact on patient management. METHODS: The study recovered 1,118 K. pneumoniae strains from various clinical specimens from hospital and community patients, from 1995 to 2004, at the Eric Williams Medical Sciences Complex. All 1,118 isolates underwent testing for multi-antibiotic resistance, of which 480 that fulfilled the criteria for possible ESBL production underwent further examination, according to guideline recommendations of the National Committee for Clinical Laboratory Standards. RESULTS: From 68,537 specimens processed, 62.9% were from hospital patients and 37.1% from community patients. Approximately 21% of the specimens yielded positive bacterial cultures from which, 1,118 were K. pneumoniae strains. Ciprofloxacin, imipenem, aztreonam, nalidixic acid and gentamicin showed the greatest efficacy (>95% sensitivity) against isolates from both hospital and community sources. Tetracycline and ampicillin showed almost 100% resistances. The other antibiotics displayed varying degrees of resistance. The prevalence of ESBL production was approximately 8.5% and most ESBL producers (51.2%) were from urine, followed by wounds (22.0%), blood (19.5%), and lower respiratory tract specimens (4.9%). Five K. pneumoniae isolates were resistant to the carbapenem, and imipenem. CONCLUSION: The study isolated K. pneumoniae from 8% of patients. All K. pneumoniae isolates were resistant to more than 2 antibiotics. The prevalence of ESBL production was 8.5%. Five (12.2%) strains of ESBL producers were resistant to imipenem. Continued infection control measures and prudent use of antibiotic agents are essential in reducing the spread of multi-resistant ESBL producing K. pneumoniae.

Pneumococcal infections in Trinidad: patterns of antimicrobial susceptibility: 1994-2002.

Antimicrobial susceptibilities of 156 Streptococcus pneumoniae strains isolated from 1994 through 2002 were studied. Of this total, 38.7, 26.3, 16.7, 8.9, and 9.6% were recovered from patients with bacteremia, pneumonia, otitis media, sinusitis, and meningitis, respectively. All S. pneumoniae strains were fully susceptible to amoxicillin-clavulanic acid and ampicillin, with 9.0 and 2.6% being resistant to penicillin and ceftriaxone, respectively. The ratios of resistant strains to tetracycline, co-trimoxazole, and chloramphenicol were 73.7, 69.3, and 63.5%, respectively. Approximately 90% of strains remain sensitive to erythromycin. A high prevalence of resistance to the penicillins and cephalosporins does not exist in Trinidad, although a trend toward such a pattern appears to be developing. The most frequent serotype was 14 (38.0%), followed by 6B (20%), 23F (10.3%), and 4 (6.4%), and all were recovered from children. The other serotypes accounted for <6% of the total isolates. All penicillin- and ceftriaxone-resistant strains belonged to serotype 14 (MIC > or = 2 microg/ml and > or = 4 microg/ml), respectively. Identifiable risk factors for resistant isolates included the prevalence of otitis media and sinusitis among children treated inadequately with oral cephalosporins; the ease of obtaining antibiotics without a prescription at many pharmacies; and the indiscriminate prescribing of antibiotics by general practitioners.

Antimicrobial susceptibility survey of Pseudomonas aeruginosa strains isolated from clinical sources.

A two-year prospective study of 554 Pseudomonas aeruginosa isolates was recovered from various clinical sources throughout Trinidad, and their resistance patterns to antipseudomonal antimicrobial agents were determined. Of the 554 P. aeruginosa isolates, 20.6% (114/554) were community isolates, 17.3% (96/554) from the intensive care unit (ICU), 10.1% (56/554) from the nursery, and the remaining 52% (288/554) were from other hospital inpatient services. Respiratory tract infections were the predominant source of P. aeruginosa isolates from the ICU--46.9% (45/96)--and nursery--21.4% (12/56), whereas wounds were the principal source of P. aeruginosa from the surgical services--77.0% (141/183). Community isolates of P. aeruginosa were predominantly from ear--100% (51/51)--and urinary tract infections--35.5%, (33/93). The overall prevalence of resistance was low for both hospital isolates (13.9%) and community isolates (3.8%). All community isolates were fully sensitive to four of the nine antimicrobials tested. Resistance rates among community strains ranged from 2.6% (ciprofloxacin and ceftazidime) to 12.3% for piperacillin. All isolates from hospital were fully sensitive to imipenem, but resistance rates for the other drugs ranged between 2.5% and 27.3%. The study showed that the overall resistance pattern of P. aeruginosa was relatively low. This is an encouraging observation but invites caution since resistance to the newly introduced drug, cefepime, has now emerged within the hospital environment and may present serious therapeutic problems within the near future. Policies governing the use of antimicrobials in many institutions are lacking. Such policies must be instituted in order to limit the spread of resistance and also to reduce the emergence of resistance to newly commissioned drugs within the country.

Antimicrobial susceptibility survey of Pseudomonas aeruginosa strains isolated from clinical sources

A two-year prospective study of 554 Pseudomonas aeruginosa isolates was recovered from various clinical sources throughout Trinidad, and their resistance patterns to antipseudomonal antimicrobial agents were determined. Of the 554 P. aeruginosa isolates, 20.6% (114/554) were community isolates, 17.3% (96/554) from the intensive care unit (ICU), 10.1% (56/554) from the nursery, and the remaining 52% (288/554) were from other hospital inpatient services. Respiratory tract infections were the predominant source of P. aeruginosa isolates from the ICU--46.9% (45/96)--and nursery--21.4% (12/56), whereas wounds were the principal source of P. aeruginosa from the surgical services--77.0% (141/183). Community isolates of P. aeruginosa were predominantly from ear--100% (51/51)--and urinary tract infections--35.5%, (33/93). The overall prevalence of resistance was low for both hospital isolates (13.9%) and community isolates (3.8%). All community isolates were fully sensitive to four of the nine antimicrobials tested. Resistance rates among community strains ranged from 2.6% (ciprofloxacin and ceftazidime) to 12.3% for piperacillin. All isolates from hospital were fully sensitive to imipenem, but resistance rates for the other drugs ranged between 2.5% and 27.3%. The study showed that the overall resistance pattern of P. aeruginosa was relatively low. This is an encouraging observation but invites caution since resistance to the newly introduced drug, cefepime, has now emerged within the hospital environment and may present serious therapeutic problems within the near future. Policies governing the use of antimicrobials in many institutions are lacking. Such policies must be instituted in order to limit the spread of resistance and also to reduce the emergence of resistance to newly commissioned drugs within the country.

Resistance patterns among selective Gram-negative bacilli from an intensive care unit in Trinidad, West Indies.

OBJECTIVE: To determine the prevalence of antimicrobial resistance among gram-negative aerobic bacteria isolated from infected patients on the intensive care unit (ICU) and the outcome of infected patients. METHODS: Over a 5-year period (January 1998 to December 2002), all gram-negative aerobic bacteria (GNB) consecutively isolated from infected ICU patients at General Hospital, San Fernando, Trinidad and Tobago, West Indies. were tested for susceptibility to 10 commonly prescribed antimicrobial agents. Bacterial strains were identified according to standard microbiological procedures. The antimicrobial agents used and the amounts consumed by patients on the ICU were obtained from the hospital pharmacy records. Hospital discharges and deaths due to infectious complications were obtained from the medical records office and the ICU. RESULTS: During the study period, there were 1160 admissions to the ICU. From this, 530 (45.7%) were suspected episodes of nosocomial infection and 445 (84%) were culture positive for GNB. Sputum, urine and blood accounted for approximately 85% of isolates. Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae), Citrobacter spp and Enterobacter spp were the predominant isolates from sputum, while from urine; it was P. aeruginosa and K. pneumoniae. The major isolate from bloodstream infection on the ICU was Citrobacter spp. Of the 10 antimicrobial agents, the least effective was ampicillin that showed 87.8% resistance, while the most effective against GNB were imipenem (94.2%), ciprofloxacin (93.9%) and piperacillin-tazobactam (88.5%). The most common isolate was P. aeruginosa which is sensitive to >82% of the antimicrobials. Antimicrobial consumption was 2282 grams and the most frequently prescribed drugs were ampicillin, cefuroxime and amoxicillin-clavulanic acid, with consumption of the beta-lactam antimicrobials being 87.3% of the total. There were 280 (24.1%) deaths on the ICU during the study period and 42.9% (120 of 280) were said to be due to, or associated with overall hospital-acquired infectious complications. Mortality associated with GNB infection was approximately 33%. All fatal cases were associated with pneumonia and bloodstream infections. The predominant organisms were Citrobacter spp, Enterobacter spp, Acinetobacter spp and P. aeruginosa, with Citrobacter spp associated with both pulmonary and bloodstream fatalities. CONCLUSION: In general, the isolates were relatively antimicrobial susceptible. Imipenem, ciprofloxacin and piperacillin-tazobactam were found good empiric choices for treatment of most GNB infection in the ICU. The study showed that resistance among ICU pathogens depended on the site of infection and that increased drug consumption of any antimicrobial agent may lead to increase resistance to those drugs. The need for policies governing the prudent use of antimicrobial agents cannot be overemphasized. Many endeavors aimed at introducing an antibiotic policy have encountered repeated failure and attempts at rational prescribing through educational programs have met with limited success. Hope is seen however, in proper implementation of infection control procedures aimed specifically to curtail lateral transmission of resistant organisms.

Colonization with Group B streptococci in pregnancy and outcome of infected neonates in Trinidad.

BACKGROUND: The present study took place at the antenatal clinics of the San Fernando General Hospital located in the south and the Mount Hope Maternity Hospital located in the north-west of the West Indies, respectively. Participants were from the lower socioeconomic group that included representatives from the two major ethnic groups, East Indians and people of African descent. METHODS: We prospectively analyzed data on 201 third trimester pregnant women. All had singleton pregnancies. Culture specimens for group B streptococcus (GBS) were obtained from the rectum and anterior one-third of the vagina, and inoculated directly onto selective media. Blood culture from neonates (born to GBS carrier mothers) suspected of sepsis was also screened for GBS. Group B streptococci were identified via colonial morphology, beta-hemolysis, and biochemical reactions, and confirmed via latex agglutination tests. Antimicrobial susceptibility testing was done. Data were computerized and statistically analyzed using the Statistical Package for the Social Sciences. Associations between age, ethnicity and gravidity were evaluated using Pearson's chi2 test. RESULTS: The prevalence of vaginal and rectal GBS colonization was 32.9%. Group B streptococci were isolated more frequently from women >24 years (36.6%) than those younger than 24 years (26.9%), and more so, from women of East Indian descent (37.3%) than women of African descent (27.2%). Colonization rates were significantly greater among multigravid women than primigravid women (P < 0.001). Of the 13 infants admitted after delivery, five were confirmed cases of sepsis. Group B streptococci were isolated from the blood of three of these infants, and one case was fatal. Although all GBS were fully sensitive to ampicillin and amoxicillin-clavulanic acid, 94% were resistant to tetracycline and approximately 88% to co-trimoxazole. Only approximately 8% were resistant to erythromycin. CONCLUSION: The carriage rate of GBS among pregnant women in the present and a previous study, remain high. Attempts to establish and implement a program aimed at GBS disease prevention have met with repeated failure. Data on the prevalence of GBS neonatal disease, preventative measures and outcome of infected infants are greatly needed.

Nosocomial infection in an Intensive Care Unit in a private hospital

The nosocomial infection rate in an Intensive care unit (ICU) of a private hospital was assessed during an 18-month survey. From 629 admissions to the ICU, 139 hospital-acquired infections were identified. The rate was 22.1 percent compared to the overall nosocomial infection rate of 15.3 percent for the entire hospital. In the ICU, the main infections occurred in the respiratory tract, 41 (29.5 percent), followed by surgical wounds, 35 (25.2 percent), urinary tract, 28 (20.1 percent) and the blood stream, 24 (17.3 percent). From 165 bacterial isolates, 80 percent of isolates were gram-negative rods, with P aeruginosa, 48 (36.6 percent), being the predominant gram-negative isolate followed by Klebsiella pneumoniae, 27 (20.6 percent), and Enterobacter sp, 22 (16.8 percent). The main gram-positive isolates were S aureus, 23 (41.8 percent), coagulase-negative Staphylococci, 17 (30.9 percent), and Enterococci, 11 (20.0 percent). Of the 23 S aureus strains, 15 (65.2 percent) were methicillin-resistant (MRSA), (8 MRSA were from surgical wounds, 5 from the respiratory tract and 2 from infected urine). Only 2 of the 17 (11.8 percent) coagulase-negative staphylococci were methicillin-resistant, and both were isolated from wounds. Resistance to ampicillin and augmentin (amoxicillin-clavulanic acid) was high, 81.9 percent and 55.4 percent, respectively. Gentamicin, azteronam, piperacillin-tazobactam showed resistance rates of less than 15 percent. Infection control measures aimed at reducing nosocomial infections at the hospital are often frustrated by apathy of hospital administrators who apparently are insensitive to the high nosocomial infection rate. Effort by the infection control team through seminars, lectures and newsletters have begun to show improvements in attitude and awareness of staff to infection control and preventative measures within the institution. (AU)

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 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.

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)

Methicillin resistance among Trinidadian isolates of community and hospital strains of Staphylococcus aureus and their patterns of resistance to non-beta-lactam antibiotics

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in Trinidad and the extent of their resistance to other antimicrobial agents in hospital-acquired infections were evaluated over a 2-year period. A total of 450 S. aureus strains were isolated from different patients. The prevalence of methicillin resistance among S. aureus strains was 9.8 percent (44/450). The proportion of MRSA isolated from hospital sources and community sources was 12.5 percent (38/305) and 4.1 percent (6/145) respectively (P<0.05). The resistant rates of MRSA to the non-beta-lactam antibodies were as follows: 93.2 percent resistance to tetracycline, 68.2 percent to erythromycin, 61.4 percent to gentamicin, 45.5 percent to co-trimoxazole, and 20.5 percent to ciprofloxacin. No MRSA resistant to vancomycin was observed in this study. Study results showed significant increases in MRSA in hospital, 2 percent in 1995 to 12.5 percent in 1998 (P<0.05), and community, 0 percent in 1995 to 4.1 percent in 1998 (P<0.05). It has become apparent that infection must be focussed now on the community in order to monitor and limit the spread of this new and expanding reservoir of MRSA. (AU)

Prevalence of Proteus species in urinary tract infections in a regional hospital in Trinidad

BACKGROUND: Proteus bacteria are a well-known cause of urinary tract infections (UTIs). The prevalence of UTIs is high among catheterized patients and those undergoing manipulation of the urinary tract. This study assessed the prevalence of UTIs due to Proteus species, the predisposing factors, complications and extent of antimicrobial resistance at a regional teaching hospital. METHODS: Urine samples in sterile containers from inpatients were inoculated onto cysteine lactose electrolyte deficient agar and sheep blood agar plates with calibrated (0.001 ml) platinum loops and incubated aerobically at 35 degrees C to 37 degrees C for 18 to 24 hours. A colony count of 10 (5) bacteria/ml or more was the criterion for significant bacteriuria. Proteus spp were identified and classifed into four groups. Susceptibility testing was performed via the Kirby-Bauer disc diffusion technique on Mueller-Hinton agar using ampicillin (10 micograms), tetracycline (30micrograms), nalidixic acid (30 micrograms), gentamicin (10 micrograms), nitrofurantoin (30 micrograms), co-trimoxazole (30 micrograms) and cefuroxime (30 micrograms). RESULTS: Of 1,397 urine specimens from hospital and community patients, 414 had one or more species of bacteria isolated, of which 74 (17.9 percent) were Proteus spp. Hospital-acquired UTIs accounted for more than two-thirds (51/74, 68.9 percent) of Proteus spp isolates, while community-acquired UTIs accounted for approximately one-third (3/74, 31.1 percent of all proteus isolates. The prevalence of proteus UTIs in male was 34 of 184 (18.5 percent) and was slightly higher than in females (40/230, 17.4 percent). P. mirabilis was the most frequently isolated proteus sp (55/74, 74.3 percent), followed by P vulgaris (9/74, 12.2 percent), Morganella morganii, (7/74, 9.5 percent) and Providencia rettgeri (3/74, 4.0 percent). Forty-nine of 55 (89 percent) P mirabilis isolates were biotype 2. Catheterization was the most common predisposing factor in 32.4 percent of hospital-acquired Proteus UTIs. More than 92 percent of Proteus isolates were sensitive to gentamicin and nalidixic acid, whereas, ampicillin (35 percent) and tetracycline (18 percent) were the least effective drugs. CONCLUSIONS: Proteus was isolated from about 18 percent of patients with significant bacteriuria. Most isolates occurred in hospitalized patients with indwelling urinary catheters and in patients with benign prostatic hypertrophy, diabetes and prostatectomy.(AU)

Paediatric nosocomial urinary tract infection at a regional hospital

From a total of 26,603 admissions to the paediatric wards, 1360 paediatric nosocomial urinary tract infections (PNUTI) were identified during a 5-year retrospective chart review at the SFGH. The ages ranged from 3 days to 13 years, with 46 percent boys and 54 percent girls. The highest rates of PNUTI per service per 100 admissions were seen in the nursery (11.28) followed by paediatric surgery (2.89) and paediatric medicine (2.86). Although the greatest number of PNUTI occurred in the nursery, comparison between the years was not statistically significant. About 90 percent (1218 of 1360) of PNUTI occurred in catheterized patients. No documentation was found specifying the type of catheterization (intermittent or continuous). About 90 percent (1210 of 1360) of isolates were single organisms with Escherichia coli, Proteus mirabilis, Klebsiellla spp. and group B streptococci accounting for a total of approximately 70 percent of all pathogens. However, the composition of the most common isolate in each service differed. The most common isolate in the nursery was E. coli, in the paediatric medical and surgical services the most common isolates were Klebsiella spp. and Proteus mirabilis, respectively. Proteus mirabilis was isolated predominantly from boys with structural abnormality of the urethral tract. No PNUTIs were complicated by bacteraemia. The antibiotics with least effectiveness (in increasing order) for UTIs were cephalexin, ampicillin, trimethoprim, co-trimoxazole and tetracycline. The most effective antibiotics were nalidixic acid, gentamicin and amoxicillin-clavulanic acid.(AU)